Sample records for variable valve train

  1. Improvement of Diesel Engine Performance by Variable Valve Train System

    Microsoft Academic Search

    T Tomoda; T Ogawa; H Ohki; T Kogo; K Nakatani; E Hashimoto

    2010-01-01

    The effects of variable valve timing and lift are studied in order to improve the thermal efficiency of a diesel engine, while maintaining low emission levels. At high load conditions, early closing of one of the intake valves or early intake valve opening realizes an enhancement of swirl intensity without increased pumping losses, and retarded intake valve closing reduces the

  2. A new electro-hydraulic variable valve-train system for I.C engine

    Microsoft Academic Search

    Fafa Liu; Hua Li; Fengjun Gao; Yunkai Wang; Mangzhi Tan; Yingnan Guo; Yaping Peng

    2010-01-01

    Abstract-It has long been known that the internal combustion (IC) engine can be significantly improved by the use of variable valve timing (WT) technologies, and the engine designers have been investigating the potential of variable valve train technologies leading to the development of camless engines for many years. In recently years, the variable valve technologies have a great improvement and

  3. Modeling and simulation of a dual-mode electrohydraulic fully variable valve train for four-stroke engines

    Microsoft Academic Search

    P. K. Wong; L. M. Tam; K. Li

    2008-01-01

    In modern four-stroke automotive engine technology, variable valve timing and lift control offer potential benefits for making\\u000a a high-performance engine. In this paper, a novel design named dual-mode electrohydraulic fully variable valve train (EHFVVT)\\u000a for both engine intake and exhaust valves is introduced. The system is mainly controlled by either proportional flow control\\u000a valves or proportional pressure relief valves, and

  4. Variable valve lift\\/timing mechanism

    Microsoft Academic Search

    R. D. Giampa; D. K. Mehaffey

    1988-01-01

    This patent describes variable lift, valve train for an internal combustion engine of the type having a body means defining a cylinder with a port. The valve train includes a valve with an axially extending valve stem located for axial movement between a valve closed an a valve open position relative to the port and normally biased to a valve

  5. Variable valve lift\\/timing mechanism

    Microsoft Academic Search

    Bonvallet

    1987-01-01

    A valve train is described for an internal combustion engine of the type having a body means defining a cylinder with a port. The valve train includes a valve with an axial extending valve stem located for axial movement in the port and normally biased to a predetermined position. A valve actuator is spaced from the valve and is operable

  6. Variable valve lift\\/timing mechanism

    Microsoft Academic Search

    Bonvallet

    1988-01-01

    This patent describes a valve train for an internal combustion engine of the type having a body means defining a cylinder with a port. The valve train includes a valve with an axial extending valve stem located for axial movement in the port and normally biased to a predetermined position; a valve actuator spaced from the valve and operable to

  7. Engine valve train system

    SciTech Connect

    Derringer, J.G.

    1986-12-09

    This patent describes a reciprocating internal combustion engine of the type having an engine block means defining at least one cylinder with an associate pair of ports, a valve located for axial movement in each of the ports with each valve normally biased to a valve closed position relative to its associate port. A rocker shaft support means is fixed to the engine block means, and a valve actuator is spaced from the valves and operable to effect reciprocation of the valves. The improvement described here comprises a rocker shaft pivotably supported by the rocker shaft support means, the rocker shaft having an axial passage adapted to be in continuous flow communication with the pressurized lubricant supply of the engine. It also includes first rocker arm pivotably supported on the rocker shaft in position for engagement with the valve actuator and with one of the valves and actuated in rocking movement whereby it can operate to effect opening and closing movement of one of the valves, and a second rocker arm pivotably supported on the rocker shaft next adjacent to the first rocker arm and operatively engaging the other one of the valves, the second rocker arm having a hydraulic cylinder means therein. A piston is sealingly journaled in the hydraulic cylinder means and located so as to permit engagement of the piston with the first rocker arm, the second rocker arm having a supply/drain passage means therein to the hydraulic cylinder means, and a drain passage which extends to the exterior of the second rocker arm and which is located in circumferentially spaced apart relationship to the supply/drain passage means.

  8. Variable pressure regulating valve

    Microsoft Academic Search

    R. H. Perkinson; C. E. Reuter

    1989-01-01

    This patent describes an apparatus for metering the weight flow of fuel (WF) to a gas turbine engine characterized by: a metering valve for metering the weight flow; PRV means for providing a constant pressure drop across the fuel metering valve by comparing a supply pressure of the weight flow with a metered pressure of the weight flow, the PRV

  9. Diagnostic for two-mode variable valve activation device

    DOEpatents

    Fedewa, Andrew M

    2014-01-07

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  10. Valve mechanism having variable valve timing

    Microsoft Academic Search

    H. Oda; S. Masuda; Y. Morita

    1986-01-01

    This patent describes a valve mechanism for an internal combustion engine which consists of a camshaft rotatable about a longitudinal axis and having a cam formed thereon, a swingable member mounted for swinging movement about the longitudinal axis of the camshaft and formed with a tappet receiving hole. A valve tapper is received in the tappet receiving hole for a

  11. A new electromagnetic engine valve actuator with less energy consumption for variable valve timing

    Microsoft Academic Search

    Jinho Kim; Dennis K. Lieu

    2007-01-01

    A variable valve timing (VVT) can improve fuel efficiency, reduce CO2 emissions and increase torque output enabling optimization\\u000a of these outputs at different engine conditions. To achieve VVT in internal combustion engine, new devices such as mechanical,\\u000a hydraulic, motor-driven and electromagnetic actuators have been developed in past years to replace the conventional camshaft\\u000a valve train system used currently. Among these,

  12. Variable-Aperture Reciprocating Reed Valve

    NASA Technical Reports Server (NTRS)

    Lindner, Jeffrey L. (Inventor); Myers, W. Neill (Inventor); Kelley, Anthony R. (Inventor); Yang, Hong Q. (Inventor)

    2015-01-01

    A variable-aperture reciprocating reed valve includes a valve body defining a through hole region having a contoured-profile portion. A semi-rigid plate is affixed on one side thereof to the valve body to define a cantilever extending across the through hole region. At least one free edge of the cantilever opposes the contoured-profile portion of the through hole region in a non-contact relationship.

  13. Multi-mode variable valve timing engine

    SciTech Connect

    Not Available

    1994-02-01

    This article examines varying valve timing and lift as well as engine displacement for better performance of four-stroke spark-ignition engines. The topics of the article include system versatility, a description of the varying mechanism, valve mode shifting, control of changeover for variable engine displacement, and engine performance in fuel economy and power.

  14. Training effect in specular spin valves

    NASA Astrophysics Data System (ADS)

    Ventura, J.; Araujo, J. P.; Sousa, J. B.; Veloso, A.; Freitas, P. P.

    2008-05-01

    Specular spin valves show an enhanced giant magnetoresistive (GMR) ratio due to specular reflection in nano-oxide layers (NOLs) formed by the partial oxidation of CoFe pinned and free layers. The oxides that form the (pinned layer) NOL were recently shown to antiferromagnetically order at Ttilde 175K . Here, we study the training effect (TE) in MnIr/CoFe/NOL/CoFe/Cu/CoFe/NOL/Ta specular spin valves in the 300-15 K temperature range. The exchange bias direction between the MnIr and CoFe layers impressed during annealing is taken as the positive direction. The training effect is observed in antiferromagnetic (AFM)/ferromagnetic (FM) exchange systems and related to the rearrangement of interfacial AFM spin structure with the number of hysteretic cycles performed (n) , resulting in the decrease of the exchange field (Hexch) . Here, in the studied specular spin valve, TE was only observed for T<175K and is thus related to the pinned layer NOL-AFM ordering and to the evolution of the corresponding spin structure with n . We show that FM spins that are strongly coupled to AFM domains do not align with the applied positive magnetic field (H) , giving rise to a residual MR at H?0 . Such nonsaturating MR will be related with a spin-glass-like behavior of the interfacial magnetism induced by the nano-oxide layer. The observed dependence of the training effect on the field cooling procedure is also likely associated with the existence of different spin configurations available in the magnetically disordered oxide. Furthermore, anomalous magnetoresistance cycles measured after cooling runs under -500Oe are here related to induced NOL exchange bias/applied magnetic field misalignment. The temperature dependence of the training effect was obtained and fitted by using a recent theoretical model.

  15. Means for variable valve timing for engine

    Microsoft Academic Search

    Oyaizu

    1988-01-01

    A variable timing camshaft drive for an internal combustion engine is described having a first cylinder bank, a first camshaft rotating about a first axis for operating at least one valve associated with the first cylinder bank, a second cylinder bank disposed at an angle to the first cylinder bank, a second camshaft rotating about a second axis for operating

  16. Investigation of a rotary valving system with variable valve timing for internal combustion engines

    Microsoft Academic Search

    Paul C. Cross; Craig N. Hansen

    1994-01-01

    The objective of the program was to provide a functional demonstration of the Hansen Rotary Valving System with Variable Valve Timing (HRVS\\/VVT), capable of throttleless inlet charge control, as an alternative to conventional poppet-valves for use in spark ignited internal combustion engines. The goal of this new technology is to secure benefits in fuel economy, broadened torque band, vibration reduction,

  17. Variable valve actuation mechanisms and the potential for their application

    Microsoft Academic Search

    R. Stone; E. Kwan

    1989-01-01

    The numerous variable valve actuation mechanisms for poppet valves need to be classified, if sensible comparisons are to be made, and one possible taxonomy is presented here. Not all the mechanisms proposed have been tested, but where they have it is usually with gasoline engines. It is well established that controlling the valve events can raise and flatten the torque

  18. Control of Variable Valve Lift Engine by Nonlinear MPC

    Microsoft Academic Search

    Akihiro Murayama; Masaki Yamakita

    2010-01-01

    In this study, we purpose a control system of engine torque for a V6 spark ignition engine with a variable valve lift system. We apply a nonlinear receding horizon control to a benchmark problem where we assume that the control inputs are throttle angle, variable valve lift and ignition timing. Moreover, a fuel injection control is also developed by estimating

  19. Modeling and control of a variable valve timing engine

    Microsoft Academic Search

    Lawrence Mianzo; Huoi Peng

    2000-01-01

    A cylinder-by-cylinder model of an experimental variable valve timing 4-cylinder engine has been developed. The model includes the cylinder and manifold mass, temperature, burned gas residual, and pressure dynamics, including combustion effects, as well as the valve actuator dynamics. The cylinder-by-cylinder model is used to obtain a cycle-averaged mapping between torque at a given engine speed and intake valve timing,

  20. Turbo-generator control with variable valve actuation

    DOEpatents

    Vuk, Carl T. (Denver, IA)

    2011-02-22

    An internal combustion engine incorporating a turbo-generator and one or more variably activated exhaust valves. The exhaust valves are adapted to variably release exhaust gases from a combustion cylinder during a combustion cycle to an exhaust system. The turbo-generator is adapted to receive exhaust gases from the exhaust system and rotationally harness energy therefrom to produce electrical power. A controller is adapted to command the exhaust valve to variably open in response to a desired output for the turbo-generator.

  1. Modular position controller for variable valve timing

    Microsoft Academic Search

    1990-01-01

    This patent describes an improvement in an internal combustion engine that has pistons reciprocating within cylinders to drive a crankshaft and valves associated with the cylinders that are operated in timed relation to the crankshaft, an engine electronic control unit that control fuel and ignition functions of the engine, means for sensing engine TDC position, means for sensing the phasing

  2. Control of Variable Valve Lift Engine by Nonlinear MPC

    NASA Astrophysics Data System (ADS)

    Murayama, Akihiro; Yamakita, Masaki

    In this study, we purpose a control system of engine torque for a V6 spark ignition engine with a variable valve lift system. We apply a nonlinear receding horizon control to a benchmark problem where we assume that the control inputs are throttle angle, variable valve lift and ignition timing. Moreover, a fuel injection control is also developed by estimating the amount of air in the engine. We propose a vehicle speed tracking control by defining time derivative of input as new input and dealing with input constraint by transformation of input variables. Finally, we show some numerical simulation results to verify the proposed methods.

  3. Engine having a variable valve actuation system

    DOEpatents

    Hefler, Gregory W. (Chillicothe, IL)

    2005-10-12

    An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

  4. Engine having a variable valve actuation system

    DOEpatents

    Hefler, Gregory W. (Chillicothe, IL)

    2004-10-12

    An engine has a cylinder head having a first surface and a second surface spaced from the first surface. A valve is moveably connected to the cylinder head. A rocker arm is connected to the valve, and a rocker shaft having a first location spaced a maximum distance from the cylinder head is connected to the rocker arm. A support member has and an actuator fluid passage network. The actuator fluid passage network defines a volume. The support member is connected to the cylinder head and is positioned such that a majority of the volume of the actuator fluid passage network is between the first location of the rocker shaft and the second surface of the cylinder head.

  5. Investigation of a rotary valving system with variable valve timing for internal combustion engines: Final technical report

    Microsoft Academic Search

    P. C. Cross; C. N. Hansen

    1994-01-01

    The objective of the program was to provide a functional demonstration of the Hansen Rotary Valving System with Variable Valve timing (HRVS\\/VVT), capable of throttleless inlet charge control, as an alternative to conventional poppet-valves for use in spark ignited internal combustion engines. The goal of this new technology is to secure benefits in fuel economy, broadened torque band, vibration reduction,

  6. Physically based volumetric efficiency model for diesel engines utilizing variable intake valve actuation

    Microsoft Academic Search

    L Kocher; E Koeberlein; D G Van Alstine; K Stricker; G Shaver

    2012-01-01

    Advanced diesel engine architectures employing flexible valve trains enable emissions reductions and fuel economy improvements. Flexibility in the valve train allows engine designers to optimize the gas exchange process in a manner similar to how common rail fuel injection systems enable optimization of the fuel injection process. Modulating valve timings directly impacts the volumetric efficiency of the engine since it

  7. A review and classification of variable valve timing mechanisms

    Microsoft Academic Search

    T. Dresner; P. Barkan

    1989-01-01

    Mechanisms for internal combustion engine variable valve timing (VVT) have been the subject of almost 800 US patents since 1880. Over 110 of these patents were issued just in the three years 1985 through 1987. Also, many technical papers have been published on VVT mechanisms. The authors reviewed all of these patents and much of the literature. As a result,

  8. The Application of Delta-Sigma Modulation to A Continuously Variable Valve Lift Engine

    Microsoft Academic Search

    Yuji Yasui; Kanako Shimojo; Kosuke Higashitani

    2007-01-01

    A continuously variable valve timing and lift system (CVTL) can improve the fuel consumption of gasoline engines by reducing of pumping losses, and provide high torque and power by optimizing intake valve lift, valve opening and valve closing according to engine load and speed conditions. In general gasoline engines, engine load is controlled by throttling. On the other hand, CVTL

  9. Ceramic valve train materials investigation for advanced industrial natural gas engine

    Microsoft Academic Search

    M. Schreiner; W. Liang; R. Kamo; R. Walson

    1987-01-01

    Valve wear has been identified as a major durability problem in natural gas fueled reciprocating engines. Over the years, progress has been made to alleviate this problem through improved valve design and materials development. Recently high performance ceramics have shown promise for wear component applications. This paper presents the results of a valve train component materials investigation supported by the

  10. ADRC for variable valve timing system of gasoline engine

    Microsoft Academic Search

    Yu He; Ying Yan; Hui Xie; Zhiqiang Gao

    2011-01-01

    The response and disturbance rejection ability of the electro-hydraulic variable valve timing(VVT)system make great influence on the performance of gasoline engine. It is a challenge for the classical linear controller because of the nonlinear behavior of the system including the mechanical wear, oil pressure, oil temperature and engine speed. The feedforward controller and liner ADRC are proposed in this paper

  11. Application of several variable-valve-timing concepts to an LHR engine

    Microsoft Academic Search

    T. Morel; R. Keribar; M. Sawlivala; N. Hakim

    1987-01-01

    An analytical study was made of advantages provided by electronically controlled hydraulically activated valves when applied to a low heat rejection engine with and without exhaust heat recovery devices. The valves, which could be designed to operate with variable timings and variable rates of opening and closing, would allow the use of certain sophisticated valve strategies not possible with conventional

  12. Advanced Technology Training System on Motor-Operated Valves

    NASA Technical Reports Server (NTRS)

    Wiederholt, Bradley J.; Widjaja, T. Kiki; Yasutake, Joseph Y.; Isoda, Hachiro

    1993-01-01

    This paper describes how features from the field of Intelligent Tutoring Systems are applied to the Motor-Operated Valve (MOV) Advanced Technology Training System (ATTS). The MOV ATTS is a training system developed at Galaxy Scientific Corporation for the Central Research Institute of Electric Power Industry in Japan and the Electric Power Research Institute in the United States. The MOV ATTS combines traditional computer-based training approaches with system simulation, integrated expert systems, and student and expert modeling. The primary goal of the MOV ATTS is to reduce human errors that occur during MOV overhaul and repair. The MOV ATTS addresses this goal by providing basic operational information of the MOV, simulating MOV operation, providing troubleshooting practice of MOV failures, and tailoring this training to the needs of each individual student. The MOV ATTS integrates multiple expert models (functional and procedural) to provide advice and feedback to students. The integration also provides expert model validation support to developers. Student modeling is supported by two separate student models: one model registers and updates the student's current knowledge of basic MOV information, while another model logs the student's actions and errors during troubleshooting exercises. These two models are used to provide tailored feedback to the student during the MOV course.

  13. Development of a variable valve timed engine to eliminate the pumping losses associated with throttled operation

    Microsoft Academic Search

    A. C. Elrod; M. T. Nelson

    1986-01-01

    The primary objective of this research program was to reduce pumping losses associated with the standard air intake system for spark ignition engines. This was accomplished by controlling the induction of the air\\/fuel charge with variable valve timing applied to the intake valves. The intake manifold pressure was maintained at atmospheric pressure and the timing of the intake valves was

  14. Speed control of vehicles with variable valve lift engine by nonlinear MPC

    Microsoft Academic Search

    Akihiro Murayama; Masaki Yamakita

    2009-01-01

    In this study, we purpose a control system of engine torque for a V6 spark ignition engine with a variable valve lift system. We apply a nonlinear receding horizon control to the SICE benchmark problem where we assume that the control inputs are throttle angle, variable valve lift and ignition timing. Moreover, a fuel injection control is also developed by

  15. Motion planning for experimental air path control of a variable-valve-timing spark ignition engine

    E-print Network

    Motion planning for experimental air path control of a variable-valve-timing spark ignition engine Spark ignition engines Time-varying systems Nonlinear observers a b s t r a c t Air path control of a spark ignition engine without an EGR loop, equipped with variable-valve-timing (VVT) actuators

  16. Airpath Control of a SI Engine with Variable Valve Timing Actuators Thomas Leroy, Jonathan Chauvin and Nicolas Petit

    E-print Network

    Airpath Control of a SI Engine with Variable Valve Timing Actuators Thomas Leroy, Jonathan Chauvin with Variable Valve Timing (VVT) actuators. VVT devices are used to produce internal exhaust gas recirculation are supported by experimental results. I. INTRODUCTION AND MOTIVATIONS Lately, Variable Valve Timing (VVT

  17. A novel electromagnetic latching device for variable valve timing in automotive engine

    Microsoft Academic Search

    Jin-Ho Kim; Joung-Hwan Chang; Se-Myung Park; Ki-Il Hwang; Jae-Yong Lee

    2010-01-01

    One of the most promising ways to improve fuel economy, reduce CO2 emissions and increase torque output is to achieve variable valve timing (VVT). Some of the devices developed in the past years include mechanical, hydraulic, motor-driven and electromagnetic actuators. Existing most advanced system is an electromagnetic actuator using solenoids to activate engine valves. It, however, needs the current continuously

  18. Emissions suppression mechanism of premixed diesel combustion with variable valve timing

    Microsoft Academic Search

    Y Murata; J Kusaka; M Odaka; Y Daisho; D Kawano; H Suzuki; H Ishii; Y Goto

    2007-01-01

    A variable valve timing (VVT) mechanism is applied to achieve premixed diesel combustion at higher load for low emissions and high thermal efficiency in a light-duty diesel engine. By means of late intake valve closing (LIVC), compressed gas temperatures near the top dead centre are lowered, thereby preventing too early ignition and increasing ignition delay to enhance fuel-air mixing. The

  19. 13 Mode Fuel Benefit Investigation Using Variable Valve Timing in a Heavy Duty Diesel Engine

    Microsoft Academic Search

    Jiamei Deng; Richard Stobart

    2009-01-01

    Variable valve actuation in heavy duty diesel engines is not well documented, partly because of diesel engine nature, such as, unthrottled air handling, which gives little room to improve pumping loss; a very high compression ratio, which makes the clearance between the piston and valve is little when the piston reaches the top dead center. It is a long time

  20. Using hybrid automata to model four stroke engines with variable valve timing in Simulink\\/Stateflow

    Microsoft Academic Search

    Brian Wesley Williams

    2006-01-01

    In this paper, I describe a Hybrid Systems Model implementation in Matlab, using Simulink and Stateflow, modeling a four stroke internal combustion engine, adding variable valve timing to increase power output, keeping other factors constant.

  1. Investigation of a rotary valving system with variable valve timing for internal combustion engines: Final technical report

    SciTech Connect

    Cross, P.C.; Hansen, C.N.

    1994-11-18

    The objective of the program was to provide a functional demonstration of the Hansen Rotary Valving System with Variable Valve timing (HRVS/VVT), capable of throttleless inlet charge control, as an alternative to conventional poppet-valves for use in spark ignited internal combustion engines. The goal of this new technology is to secure benefits in fuel economy, broadened torque band, vibration reduction, and overhaul accessibility. Additionally, use of the variable valve timing capability to vary the effective compression ratio is expected to improve multi-fuel tolerance and efficiency. Efforts directed at the design of HRVS components proved to be far more extensive than had been anticipated, ultimately requiring that proof-trial design/development work be performed. Although both time and funds were exhausted before optical or ion-probe types of in-cylinder investigation could be undertaken, a great deal of laboratory data was acquired during the course of the design/development work. This laboratory data is the basis for the information presented in this Final Report.

  2. The application of a two-input cam-actuated mechanism to variable valve timing

    Microsoft Academic Search

    T. L. Dresner; P. Barkan

    1989-01-01

    Little of the long-recognized potential of variable valve timing (VVT) has yet been realized, mainly because of the many limitations that characterize virtually all the mechanisms that have been proposed for VVT application. These limitations include high cost and complexity, mechanism energy losses, limited range of variability, and high valve impact velocities. The authors have developed a two-degree-of-freedom mechanism, actuated

  3. A lost-motion, variable-valve-timing system for automotive piston engines

    Microsoft Academic Search

    R. J. Herrin; D. J. Pozniak

    1984-01-01

    A simple, passive, lost-motion mechanism for varying the timings of engine valve opening and closing events has been developed and evaluated. The mechanism was found to be durable and precise in its control. When applied to a high-specific-output engine, the mechanism allowed much lower idle speeds and reduced idle fuel consumption without compromising high-speed power. However, valve-train noise was increased

  4. Artificial neural-network based modeling of variable valve-timing in a spark-ignition engine

    Microsoft Academic Search

    Mustafa Gölcü; Yakup Sekmen; Perihan Erduranl?; M. Sahir Salman

    2005-01-01

    Variable valve-timing and lift are significant operating and design parameters affecting the performance and emissions in spark-ignition (SI) engines. Previous investigations have demonstrated that improvements in engine performance can be accomplished if the valve timing is variable. Traditionally, valve timing has been designed to optimize operation at high engine-speed and wide-open throttle conditions. Controlling valve timing can improve the torque

  5. VALVE: Variable Length Value Encoder for Off-Chip Data Buses. Dinesh C. Suresh, Banit Agrawal*

    E-print Network

    Najjar, Walid A.

    times more frequent than that of full match events. We propose VAriable Length Value Encoding (VALVEVALVE: Variable Length Value Encoder for Off-Chip Data Buses. Dinesh C. Suresh, Banit Agrawal proposed scheme is capable of detecting and encoding variable length bit patterns in the data values. VALVE

  6. Internal combustion engine with rotary valve assembly having variable intake valve timing

    Microsoft Academic Search

    C. N. Hansen; P. C. Cross

    1995-01-01

    An internal combustion engine has rotary valves associated with movable shutters operable to vary the closing of intake air\\/fuel port sections to obtain peak volumetric efficiency over the entire range of speed of the engine. The shutters are moved automatically by a control mechanism that is responsive to the RPM of the engine. A foot-operated lever associated with the control

  7. Internal combustion engine with rotary valve assembly having variable intake valve timing

    DOEpatents

    Hansen, Craig N. (Eden Prairie, MN); Cross, Paul C. (Shorewood, MN)

    1995-01-01

    An internal combustion engine has rotary valves associated with movable shutters operable to vary the closing of intake air/fuel port sections to obtain peak volumetric efficiency over the entire range of speed of the engine. The shutters are moved automatically by a control mechanism that is responsive to the RPM of the engine. A foot-operated lever associated with the control mechanism is also used to move the shutters between their open and closed positions.

  8. Flatness-Based Tracking of an Electromechanical Variable Valve Timing Actuator With Disturbance Observer Feedforward Compensation

    Microsoft Academic Search

    Ryan R. Chladny; Charles R. Koch

    2008-01-01

    A comprehensive control strategy for an automotive solenoid variable valve timing actuator is presented that addresses the issues of feedback sensors, soft seating or landing control, disturbance rejection and feedforward design. In particular, the motion control of the engine exhaust valve actuator subject to large cycle-to-cycle gas force variations is successfully demonstrated in simulation and on an experimental test-bench. Also

  9. Effect Analysis of Design Variables on the Disc in a Double-Eccentric Butterfly Valve

    PubMed Central

    Kim, Da-Eun; Kim, Kuk-Kyeom; Kim, Jun-Oh

    2014-01-01

    We have performed a shape optimization of the disc in an industrial double-eccentric butterfly valve using the effect analysis of design variables to enhance the valve performance. For the optimization, we select three performance quantities such as pressure drop, maximum stress, and mass (weight) as the responses and three dimensions regarding the disc shape as the design variables. Subsequently, we compose a layout of orthogonal array (L16) by performing numerical simulations on the flow and structure using a commercial package, ANSYS v13.0, and then make an effect analysis of the design variables on the responses using the design of experiments. Finally, we formulate a multiobjective function consisting of the three responses and then propose an optimal combination of the design variables to maximize the valve performance. Simulation results show that the disc thickness makes the most significant effect on the performance and the optimal design provides better performance than the initial design. PMID:24883380

  10. Dynamic feedback linearization of Diesel engines with intake variable valve actuation

    Microsoft Academic Search

    A. Plianos; Richard Stobart

    2007-01-01

    In this paper, a nonlinear control technique based on the property of flatness is proposed to control the air system of new generation diesel engines. The simulated engine is equipped with variable valve actuation (VVA), variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR). The control objective is to achieve tracking of suitable references of flat outputs with corresponding intake

  11. Variable valve timing for fuel economy improvement in a small spark-ignition engine

    Microsoft Academic Search

    G. Fontana; E. Galloni

    2009-01-01

    The potential of a simple variable valve timing (VVT) system has been investigated. This system has been designed to update a small displacement engine pursuing the objective of optimizing both engine performance and, particularly, fuel consumption at part load operation. A continuously variable cam phaser (CVCP), able to produce a reverse Miller cycle effect during the intake phase and a

  12. Working characteristics of variable intake valve in compressed air engine.

    PubMed

    Yu, Qihui; Shi, Yan; Cai, Maolin

    2014-01-01

    A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine. PMID:25379536

  13. Two-stroke-cycle engine with variable valve timing

    Microsoft Academic Search

    W. E. Richeson; F. L. Erickson

    1992-01-01

    This patent describes the method of operating a two-stroke-cycle internal combustion engine, having a two-stroke engine cycle, at a controllable fuel to air mixture ratio. It comprises varying the time in the cycle at which an exhaust valve is closed under varying load and engine speed conditions and correspondingly varying the quantity of fuel introduced into the engine combustion chamber

  14. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the...

  16. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the...

  17. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the...

  18. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Interlocking Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the...

  19. Variable valve timing in a homogenous charge compression ignition engine

    DOEpatents

    Lawrence, Keith E.; Faletti, James J.; Funke, Steven J.; Maloney, Ronald P.

    2004-08-03

    The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.

  20. ESTIMATION OF EXHAUST MANIFOLD PRESSURE IN TURBOCHARGED GASOLINE ENGINES WITH VARIABLE VALVE TIMING

    E-print Network

    Grizzle, Jessy W.

    and increasing cost. As such, strategies are highly #12;scrutinized prior to implementation and those with added of the feedforward controller. When variable valve timing is added, the significance of Pe rises dramatically, since to market pressures dictate a simple and efficient estimation algorithm. Online computing resources

  1. Homogeneous charge compression ignition of LPG and gasoline using variable valve timing in an engine

    Microsoft Academic Search

    Kitae Yeom; Jinyoung Jang; Choongsik Bae

    2007-01-01

    The combustion characteristics and exhaust emissions in an engine were investigated under homogeneous charge compression ignition (HCCI) operation fueled with liquefied petroleum gas (LPG) and gasoline with regard to variable valve timing (VVT) and the addition of di-methyl ether (DME). LPG is a low carbon, high octane number fuel. These two features lead to lower carbon dioxide (CO2) emission and

  2. Airpath control of a SI engine with Variable Valve Timing actuators

    Microsoft Academic Search

    Thomas Leroy; Jonathan Chauvin; Nicolas Petit

    2008-01-01

    We address the control of the airpath of a turbocharged SI engine equipped with variable valve timing (VVT) actuators. VVT devices are used to produce internal exhaust gas recirculation, providing beneficial effects in terms of consumption and pollutant emissions reduction. However, VVT actuators affect the fresh air charge in the cylinders. This has an impact on the torque output (leading

  3. Design and application of fuzzy control system of engine variable valve timing

    Microsoft Academic Search

    Chang Wenxiu; Li Liguang; Tao Jianwu; Xiao Min; Zeng Zhaoyang

    1999-01-01

    In this paper, a design method of fuzzy control system of engine variable valve timing (VVT) is proposed. In this system, the fuzzy controller is used. The VVT system adopted fuzzy controller eliminates shortcomings in traditional control method such as low accuracy and unsteadiness etc. It has been proved by vehicle road test that the system is effective to meet

  4. Study on Modeling of Electro-Hydraulic Variable Valve Mechanism Based on CATIA

    Microsoft Academic Search

    Yanhua Gu; Hua Li; Fafa Liu; Yunkai Wang; Yingnan Guo

    2010-01-01

    This paper describes a modeling method for electro-hydraulic variable valve mechanism based on CATIA. It focuses on the principle of the mechanism and the models of some parts with oil circuits in the hydraulic system and the moving principle of the actuation system. The additional damping cavity is used for pressure compensation. The actual mechanism based on the model precisely

  5. Variable valve closure timing for load control and the Otto Atkinson cycle engine

    Microsoft Academic Search

    R. J. Saunders; E. A. Abul-Wahab

    1989-01-01

    Two fundamental methods of improving the brake specific fuel consumption of a spark ignition engine at part load have been investigated. These comprise the reduction of pumping losses by variable intake valve timing and changes of clearance volume to increase the expansion ratio. The resulting Otto-Atkinson cycle engine competes with the Diesel cycle engine. Test bed results from a four

  6. Regulator valve for hydraulic control system including variable displacement pump

    Microsoft Academic Search

    T. Shibayama; K. Sugano

    1986-01-01

    A hydraulic control system is described for an automotive automatic transmission comprising: an automatic transmission actuated by hydraulic fluid; a variable capacity pump for supplying hydraulic fluid under pressure for actuating the automatic transmission. The pump has a control arrangement including a control chamber which varies the capacity of the pump in response to the pressure prevailing therein. A pressure

  7. Optimization of variable valve timing for maximizing performance of an unthrottled SI engine—a theoretical study

    Microsoft Academic Search

    E. Sher; T. Bar-Kohany

    2002-01-01

    Previous investigations have demonstrated that improvements in gasoline engine performance can be accomplished if the valve timing is variable. In this work valve timing strategies for maximizing engine torque and minimizing bsfc in terms of the exhaust opening (EO), intake opening (IO) and intake closing (IC) timings of a commercial SI engine are studied. The MICE (Modeling Internal Combustion Engines)

  8. What Variables Appear Important in Changing Traditional Inservice Training Procedures.

    ERIC Educational Resources Information Center

    Sobol, Francis Thomas

    Herein are discussed descriptive findings from the educational literature on the question of what variables appear important in changing traditional in-service training procedures. The question of the content versus the process of in-service training, important problems in in-service training programs, and implications of the important problems…

  9. Loop Heat Pipe with Thermal Control Valve as a Variable Thermal Link

    NASA Technical Reports Server (NTRS)

    Hartenstine, John; Anderson, William G.; Walker, Kara; Dussinger, Pete

    2012-01-01

    Future lunar landers and rovers will require variable thermal links that allow for heat rejection during the lunar daytime and passively prevent heat rejection during the lunar night. During the lunar day, the thermal management system must reject the waste heat from the electronics and batteries to maintain them below the maximum acceptable temperature. During the lunar night, the heat rejection system must either be shut down or significant amounts of guard heat must be added to keep the electronics and batteries above the minimum acceptable temperature. Since guard heater power is unfavorable because it adds to system size and complexity, a variable thermal link is preferred to limit heat removal from the electronics and batteries during the long lunar night. Conventional loop heat pipes (LHPs) can provide the required variable thermal conductance, but they still consume electrical power to shut down the heat transfer. This innovation adds a thermal control valve (TCV) and a bypass line to a conventional LHP that proportionally allows vapor to flow back into the compensation chamber of the LHP. The addition of this valve can achieve completely passive thermal control of the LHP, eliminating the need for guard heaters and complex controls.

  10. Training variability in the evaluation of automated classifiers

    NASA Astrophysics Data System (ADS)

    Chen, Weijie; Gallas, Brandon D.

    2010-03-01

    The evaluation of automated classifiers in computer-aided diagnosis of medical images often involves a training dataset for classifier design and a test dataset for performance estimation in terms of, e.g., area under the receiver operating characteristic (ROC) curve, or AUC. The traditional approach to assess the uncertainty of the estimated AUC only considers the finite testing set as the source of variability. However, a finite training set is also a random sample and the AUC varies with varying training sets. We categorize the assessment of classifiers into three levels and provide analytical expressions for the variance of the estimated AUC at each level: (1) training treated as a fixed effect, the estimated performance generalizable only to the population of testing sets; (2) training treated as a random effect, the estimated performance generalizable to both the population of training sets and the population of testing sets; (3) training treated as a random effect, performance averaged over training sets generalizable to both the population of training sets and the population of testing sets. The two sources of variability - training and testing - in automated classifiers are analogous to readers and cases in the multi-reader multi-case (MRMC) ROC paradigm in reader studies. We show the one-to-one analogy between the automated classifiers and human readers at these three levels as well as the practical difference in estimating their performance, especially regarding variance.

  11. Training models of anatomic shape variability

    PubMed Central

    Merck, Derek; Tracton, Gregg; Saboo, Rohit; Levy, Joshua; Chaney, Edward; Pizer, Stephen; Joshi, Sarang

    2008-01-01

    Learning probability distributions of the shape of anatomic structures requires fitting shape representations to human expert segmentations from training sets of medical images. The quality of statistical segmentation and registration methods is directly related to the quality of this initial shape fitting, yet the subject is largely overlooked or described in an ad hoc way. This article presents a set of general principles to guide such training. Our novel method is to jointly estimate both the best geometric model for any given image and the shape distribution for the entire population of training images by iteratively relaxing purely geometric constraints in favor of the converging shape probabilities as the fitted objects converge to their target segmentations. The geometric constraints are carefully crafted both to obtain legal, nonself-interpenetrating shapes and to impose the model-to-model correspondences required for useful statistical analysis. The paper closes with example applications of the method to synthetic and real patient CT image sets, including same patient male pelvis and head and neck images, and cross patient kidney and brain images. Finally, we outline how this shape training serves as the basis for our approach to IGRT?ART. PMID:18777919

  12. Combustion, Control, and Fuel Effects in a Spark Assisted HCCI Engine Equipped with Variable Valve Timing

    SciTech Connect

    Bunting, Bruce G [ORNL

    2006-01-01

    Widespread implementation of homogeneous charge compression ignition (HCCI) engines is presently hindered by stability, control, and load range issues. Although the operable HCCI speed/load range is expanding, it is likely that the initial HCCI engines will rely on conventional combustion for part of the operating cycle. In the present study, we have investigated the role of fuel properties and chemistry on the operation of a spark-assisted gasoline HCCI engine. The engine employed is a single cylinder, 500 cc, port fuel injected research engine, operating near lambda = 1.0 and equipped with hydraulic variable valve actuation. HCCI is initiated by early exhaust valve closing to retain exhaust in the cylinder, thereby increasing the cylinder gas temperature. This is also referred to as a 'negative overlap' strategy. A total of 10 custom blended gasolines and three different batches of indolene from two suppliers were run at 5 speed-load combinations and performance was characterized by timing sweeps. Within the quality of the data set, we can say the all fuels provided equivalent combustion and performance characteristics when compared at the same combustion phasing. The fuels did, however, require different degrees of retained exhaust as measured by exhaust valve closing angle to achieve the same combustion phasing. Fuels with higher octane sensitivity were found to ignite more easily or more quickly and to burn more quickly than fuels with lower octane sensitivity. This is an expected result since the engine is naturally aspirated and operates with high compression temperatures due to the high retained exhaust fraction and recompression.

  13. Blood Pressure Variability and Stress Management Training for Essential Hypertension

    ERIC Educational Resources Information Center

    Garcia-Vera, Maria Paz; Sanz, Jesus; Labrador, Francisco J.

    2004-01-01

    The purpose of this study was to determine whether stress management training reduces blood pressure (BP) variability in hypertensive patients. Previous literature suggests that cardiovascular risk is not only a function of BP levels, but also of BP variability, and this partially depends on changes induced by the stress of everyday life. The…

  14. A fault diagnosis approach for diesel engine valve train based on improved ITD and SDAG-RVM

    NASA Astrophysics Data System (ADS)

    Yu, Liu; Junhong, Zhang; Fengrong, Bi; Jiewei, Lin; Wenpeng, Ma

    2015-02-01

    Targeting the non-stationary characteristics of the vibration signals of a diesel engine valve train, and the limitation of the autoregressive (AR) model, a novel approach based on the improved intrinsic time-scale decomposition (ITD) and relevance vector machine (RVM) is proposed in this paper for the identification of diesel engine valve train faults. The approach mainly consists of three stages: First, prior to the feature extraction, non-uniform B-spline interpolation is introduced to the ITD method for the fitting of baseline signal, then the improved ITD is used to decompose the non-stationary signals into a set of stationary proper rotation components (PRCs). Second, the AR model is established for each PRC, and the first several AR coefficients together with the remnant variance of all PRCs are regarded as the fault feature vectors. Finally, a new separability based directed acyclic graph (SDAG) method is proposed to determine the structure of multi-class RVM, and the fault feature vectors are classified using the SDAG-RVM classifier to recognize the fault of the diesel engine valve train. The experimental results demonstrate that the proposed fault diagnosis approach can effectively extract the fault features and accurately identify the fault patterns.

  15. A hybrid disturbance rejection control solution for variable valve timing system of gasoline engines.

    PubMed

    Xie, Hui; Song, Kang; He, Yu

    2014-07-01

    A novel solution for electro-hydraulic variable valve timing (VVT) system of gasoline engines is proposed, based on the concept of active disturbance rejection control (ADRC). Disturbances, such as oil pressure and engine speed variations, are all estimated and mitigated in real-time. A feed-forward controller was added to enhance the performance of the system based on a simple and static first principle model, forming a hybrid disturbance rejection control (HDRC) strategy. HDRC was validated by experimentation and compared with an existing manually tuned proportional-integral (PI) controller. The results show that HDRC provided a faster response and better tolerance of engine speed and oil pressure variations. PMID:24238361

  16. Limit-push training reduces motor variability

    Microsoft Academic Search

    Ian Sharp; James L. Patton

    2011-01-01

    Variability in human motor control has been a long observed phenomenon, which has come to be known by some as repetition without repetition. There are several explanations for this. One such explanation asserts that many equally optimal solutions exist for accomplishing the same task that naturally allows choices in how it can be successfully executed. The aim of this study

  17. A high power, wide torque range, efficient engine with a newly developed variable-valve-lift and -timing mechanism

    Microsoft Academic Search

    K. Inoue; K. Nagahiro; Y. Ajiki; N. Kishi

    1989-01-01

    A variable valving system was developed. This system has two cam profiles, one for low speed and one for high speed. A 1.2-litre DOHC experimental engine using this system was made and mounted in the body of a 2-litre class passenger car. Test results of this car were compared to those of the same car with its original engine. The

  18. Impact of variable valve timing on power, emissions and backfire of a bi-fuel hydrogen\\/gasoline engine

    Microsoft Academic Search

    S. Verhelst; J. Demuynck; R. Sierens; P. Huyskens

    2010-01-01

    Hydrogen-fueled internal combustion engines are a possible solution to make transportation more ecological. Apart from difficulties in production and storage of hydrogen, there are three major bottlenecks in the operation of hydrogen-powered engines: reaching a high power output, reducing NOx emissions at high loads and avoiding backfire. This paper presents an experimental study of the influence of continuously variable valve

  19. A physics-based approach to the control of homogeneous charge compression ignition engines with variable valve actuation

    Microsoft Academic Search

    G M Shaver; M J Roelle; P A Caton; N B Kaahaaina; N Ravi; J-P Hathout; J Ahmed; A Kojic; C F Edwards; J C Gerdes

    2005-01-01

    Homogeneous charge compression ignition (HCCI) is a promising low-temperature combustion strategy for reducing NOx emissions and increasing efficiency in internal combustion engines. However, HCCI has no direct combustion initiator and, when achieved by reinducting or trapping residual exhaust gas with a variable valve actuation (VVA) system, becomes a dynamic process as the temperature of the residual gas couples one cycle

  20. Addressing Cultural Variables in Parent Training Programs with Latino Families

    ERIC Educational Resources Information Center

    Barker, Chikira H.; Cook, Katrina L.; Borrego, Joaquin, Jr.

    2010-01-01

    There has recently been increased attention given to understanding how cultural variables may have an impact on the efficacy of treatments with Latino families seeking psychological services. Within parent training programs, understanding the extent to which culture can affect parenting practices is vital to providing quality care. The focus of…

  1. The assessment of variable valve timing of internal combustion engines for fuel economy improvements and practicability. Final report Aug 79Mar 81

    Microsoft Academic Search

    T. Jr Taylor; R. L. Kallin

    1981-01-01

    This project studied the results of previous research on the potential effects of variable valve timing for improving automotive engine fuel economy. Methods of implementation of valve timing control and their practicality were also assessed. Some of the sources claim fuel economy improvements as high as 18 to 20% but conclusions suffer from insufficient test data as well as a

  2. System for detecting operating errors in a variable valve timing engine using pressure sensors

    DOEpatents

    Wiles, Matthew A.; Marriot, Craig D

    2013-07-02

    A method and control module includes a pressure sensor data comparison module that compares measured pressure volume signal segments to ideal pressure volume segments. A valve actuation hardware remedy module performs a hardware remedy in response to comparing the measured pressure volume signal segments to the ideal pressure volume segments when a valve actuation hardware failure is detected.

  3. Hydraulic damper for vehicles with variable orifice piston valving for varying damping force

    Microsoft Academic Search

    W. V. Fannin; H. C. Jr. Buchanan

    1987-01-01

    A hydraulic damping unit is described for controlling the spring action of vehicle suspension springs comprising a cylinder tube having a hydraulic fluid therein, a valved piston having a generally cylindrical body mounted for linear stroking movement in the cylinder tube and hydraulically separating the cylinder tube into first and second chambers, valve means within the body of the piston

  4. Zebra tape identification for the instantaneous angular speed computation and angular resampling of motorbike valve train measurements

    NASA Astrophysics Data System (ADS)

    Rivola, Alessandro; Troncossi, Marco

    2014-02-01

    An experimental test campaign was performed on the valve train of a racing motorbike engine in order to get insight into the dynamic of the system. In particular the valve motion was acquired in cold test conditions by means of a laser vibrometer able to acquire displacement and velocity signals. The valve time-dependent measurements needed to be referred to the camshaft angular position in order to analyse the data in the angular domain, as usually done for rotating machines. To this purpose the camshaft was fitted with a zebra tape whose dark and light stripes were tracked by means of an optical probe. Unfortunately, both manufacturing and mounting imperfections of the employed zebra tape, resulting in stripes with slightly different widths, precluded the possibility to directly obtain the correct relationship between camshaft angular position and time. In order to overcome this problem, the identification of the zebra tape was performed by means of the original and practical procedure that is the focus of the present paper. The method consists of three main steps: namely, an ad-hoc test corresponding to special operating conditions, the computation of the instantaneous angular speed, and the final association of the stripes with the corresponding shaft angular position. The results reported in the paper demonstrate the suitability of the simple procedure for the zebra tape identification performed with the final purpose to implement a computed order tracking technique for the data analysis.

  5. Multirate closed-loop system identification of a variable valve timing actuator for an internal combustion engine

    Microsoft Academic Search

    Zhen Ren; Guoming G. Zhu

    2010-01-01

    This paper applies the multi-rate closed-loop system identification (ID) technique to a continuously variable valve timing (VVT) actuator system. Limited by the sample rate of the crank-based cam position sensor, function of engine speed, the actuator control sample rate is different from that of cam position sensor. Multi-rate system identification is a necessity for this application. On the other hand,

  6. Bias and variability of diagnostic spectral parameters extracted from closing sounds produced by bioprosthetic valves implanted in the mitral position

    Microsoft Academic Search

    ROBERT GUARDO; HANI N. SABBAH; PAUL D. STEIN

    1989-01-01

    A method is proposed to estimate the bias and variability of eight diagnostic spectral parameters extracted from mitral closing sounds produced by bioprosthetic heart valves. These spectral param- eters are: the frequency of the dominant (Fl) and second dominant (F2) spectral peaks, the highest frequency of the spectrum found at -3 dB (F-3), -10 dB (F-10) and -20 dB (F-20)

  7. Resonant Frequency Biofeedback Training to Increase Cardiac Variability: Rationale and Manual for Training

    Microsoft Academic Search

    Paul M. Lehrer; Evgeny Vaschillo; Bronya Vaschillo

    2000-01-01

    Heart rate and blood pressure, as well as other physiological systems, among healthy peo- ple, show a complex pattern of variability, characterized by multifrequency oscillations. There is evidence that these oscillations reflect the activity of homeostatic reflexes. Biofeed- back training to increase the amplitude of respiratory sinus arrhythmia (RSA) maximally increases the amplitude of heart rate oscillations only at approximately

  8. INCREASING RESPONSE VARIABILITY OF MAND FRAMES WITH SCRIPT TRAINING AND EXTINCTION

    PubMed Central

    Betz, Alison M; Higbee, Thomas S; Kelley, Kristen N; Sellers, Tyra P; Pollard, Joy S

    2011-01-01

    We examined the effects of script training and extinction on response variability of mand frames used by children with autism. Results demonstrated that extinction following script training was effective for increasing variability for 2 of the 3 participants. PMID:21709793

  9. Increasing response variability of mand frames with script training and extinction.

    PubMed

    Betz, Alison M; Higbee, Thomas S; Kelley, Kristen N; Sellers, Tyra P; Pollard, Joy S

    2011-01-01

    We examined the effects of script training and extinction on response variability of mand frames used by children with autism. Results demonstrated that extinction following script training was effective for increasing variability for 2 of the 3 participants. PMID:21709793

  10. Variable-pulse switching circuit accurately controls solenoid-valve actuations

    NASA Technical Reports Server (NTRS)

    Gillett, J. D.

    1967-01-01

    Solid state circuit generating adjustable square wave pulses of sufficient power operates a 28 volt dc solenoid valve at precise time intervals. This circuit is used for precise time control of fluid flow in combustion experiments.

  11. Developing a Training Tool for Intraoperative Mitral Valve Analysis Neil A. Tenenholtz, Robert D. Howe

    E-print Network

    , a healthy mitral valve permits the flow of oxygenated blood from the left atrium to the left ventricle while with the Fig. 2 Subjects use the surgical simulator to analyze the mobility of leaflet segments. The blue the flow of oxygenated blood.

  12. Cycle-to-cycle variation analysis of in-cylinder flow in a gasoline engine with variable valve lift

    NASA Astrophysics Data System (ADS)

    Liu, Daming; Wang, Tianyou; Jia, Ming; Wang, Gangde

    2012-09-01

    In spark ignition engines, cycle-to-cycle variation (CCV) limits the expansion of the operating range because it induces the load variations and the occurrence of misfire and/or knock. Variable valve actuation (VVA) or variable valve lift (VVL) has been widely used in SI engines to improve the volumetric efficiency or to reduce the pumping losses. It is necessary to investigate the CCV of in-cylinder gas motion and mixing processes in SI engines with VVA/VVL system. This study is aimed to analyze the CCV of the tumble flow in a gasoline direct injection (GDI) engine when VVL is employed. Cycle-resolved digital particle image velocimetry (CRD-PIV) data were acquired for the in-cylinder flow field of a motored four-stroke multi-valve GDI optical engine. The CCV of in-cylinder gas motion with a series of valve profiles and different maximum valve lift (MVL) was analyzed, including cyclic variation characteristics of bulk flow (tumble centre and tumble ratio), large- and small-scale fluctuation, total kinetic energy, and circulation. The results show that the CCV of the in-cylinder flow is increased with reduced MVL. With lower MVLs, stable tumble flow cannot be formed in the cylinder, and the ensemble-averaged tumble ratio decreases to zero before the end of the compression stroke due to violent variation. In addition, the evolution of the circulation shows larger variation with lower MVLs that indicates the `spin' of the small-scale eddy in the flow field presents violent fluctuation from one cycle to another, especially at the end of the compression stroke. Moreover, the analyze of the kinetic energy indicates the total energy of the flow field with lower MVLs increases significantly comparing with higher MVL conditions due to the intake flow jet at the intake valve seat in the intake stroke. However, the CCV of the in-cylinder flow becomes more violent under lower MVL conditions, especially for the low-frequency fluctuation kinetic energy. Thus, present strong tumble flow can lower the CCV of the air motion. It is necessary to manage strong tumble or other bulk flow (such as swirl flow) in order to improve the stability of ignition and combustion for GDI engines with VVL, especially at the lower MVL conditions.

  13. Incidence and management of subdural hematoma/hygroma with variable- and fixed-pressure differential valves: a randomized, controlled study of programmable compared with conventional valves.

    PubMed

    Carmel, P W; Albright, A L; Adelson, P D; Canady, A; Black, P; Boydston, W; Kneirim, D; Kaufman, B; Walker, M; Luciano, M; Pollack, I F; Manwaring, K; Heilbrun, M P; Abbott, I R; Rekate, H

    1999-10-15

    Shunt systems with differential pressure valves are prone to the complications of overdrainage. A programmable valve permits adjustment of the opening pressure of the valve. In this paper the authors report the incidence of subdural fluid collections in a randomized trial of programmable compared with conventional valves, and they describe methodologies used in management of this complication. A multiinstitutional, prospective, randomized trial of the Codman Hakim programmable valve and conventional fixed-pressure valves was undertaken. Two classes were defined: "new" and "replacement" valves. Randomization of the type of valve in each group was performed at each study site. Clinical and radiological studies were required at fixed intervals over a 104-week period. All complications were reported. The experimental valves were required to be reprogrammed after magnetic resonance imaging studies, but all other decisions regarding pressure setting were left to each investigator. Three hundred seventy-seven patients were randomized; 194 were treated with a programmable valve and 183 with a fixed-pressure valve. The two groups were statistically similar in demographic composition, as were the "new" and "replacement" categories. The investigators made 540 valve pressure changes (five per patient; range one-41 changes). More than half of the reprogramming adjustments were made in the first 3 months postplacement; 70% were made within 6 months. More than half of all reprogramming adjustments were required in a group of 30 patients. Four treatment modalities were observed: 1) 30% of the fluid collections resolved spontaneously (25% in the patients with programmable valves and 36.3% in those with conventional valves) and were largely found to be hygromas in infants and children; 2) four subdural fluid collections were unresolved and under observation; 3) the subdural hematoma was drained and the shunt removed (in 8.3% of patients with the programmable valve and 36.3% of those with the control valve); 4) the pressure of programmable valve was raised in 58% of patients (seven of 12), and this increase in opening pressure was a feature used by investigators to affect treatment. There was no significant difference in the incidence of subdural fluid collections between the programmable and fixed-pressure valve treatment groups. The programmable feature provided a considerable advantage in treatment when subdural collections occurred. PMID:16918220

  14. Dynamic control of a SI engine with variable intake valve timing

    Microsoft Academic Search

    Jun-Mo Kang; J. W. Grizzle

    2003-01-01

    SUMMARY Engines equipped with a means to actuate air flow at the intake valve can achieve superior fuel economy performance in steady state. This paper shows how modern nonlinear design techniques can be used to control such an engine over a wide range of dynamic conditions. The problem is challenging due to the nonlinearities and delays inherent in the engine

  15. Burn angles and form factors for Wiebe function fits to mass fraction burned curves of a spark ignition engine with variable valve timing

    Microsoft Academic Search

    F Bonatesta; B Waters; P J Shayler

    2010-01-01

    The charge burn characteristics of a port-injected spark ignition engine with a pent-roof combustion chamber and variable valve timing have been investigated experimentally. The engine was run under stoichiometric mixture operating conditions over ranges of intake and exhaust valve timings, engine speed, and engine load. Empirical functions have been developed for the 0–90 per cent mass fraction burned angle and

  16. Eight weeks of intermittent hypoxic training improves submaximal physiological variables in highly trained runners.

    PubMed

    Holliss, Ben A; Burden, Richard J; Jones, Andrew M; Pedlar, Charles R

    2014-08-01

    It is unclear whether intermittent hypoxic training (IHT) results in improvements in physiological variables associated with endurance running. Twelve highly trained runners (VO2peak 70.0 ± 3.5 ml·kg-1·min-1) performed incremental treadmill tests to exhaustion in normobaric normoxia and hypoxia (16.0% FIO2) to assess submaximal and maximal physiological variables and the limit of tolerance (T-Lim). Participants then completed 8 weeks of moderate to heavy intensity normoxic training (control [CONT]) or IHT (twice weekly 40 minutes runs, in combination with habitual training), in a single blinded manner, before repeating the treadmill tests. Submaximal heart rate decreased significantly more after IHT (-5 ± 5 b·min-1; p = 0.001) than after CONT ( -1 ± 5 b·min-1; p = 0.021). Changes in submaximal V[Combining Dot Above]O2 were significantly different between groups (p ? 0.05); decreasing in the IHT group in hypoxia (-2.6 ± 1.7 ml·kg-1·min-1; p = 0.001) and increasing in the CONT group in normoxia (+1.1 ± 2.1 ml·kg-1·min-1; p = 0.012). There were no VO2peak changes within either group, and while T-Lim improved post-IHT in hypoxia (p = 0.031), there were no significant differences between groups. Intermittent hypoxic training resulted in a degree of enhanced cardiovascular fitness that was evident during submaximal, but not maximal intensity exercise. These results suggest that moderate to heavy intensity IHT provides a mean of improving the capacity for submaximal exercise and may be useful for pre-acclimatization for subsequent exercise in hypoxia, but additional research is required to establish its efficacy for athletic performance at sea level. PMID:24513622

  17. Valve Disease

    MedlinePLUS

    ... have had heart valve surgery and have a prosthetic valve made of synthetic material. Beta-blockers control ... defective valve and stitching in its place a prosthetic valve. Prosthetic valves can either be mechanical (made ...

  18. Pressure regulator valve by Bondgraph

    Microsoft Academic Search

    Katsuya Suzuki; Ikuo Nakamura; Jean Thoma

    1999-01-01

    The Bondgraph represents mechanical, hydraulic and electric components with their power flow in an unified manner and is used here for a three port regulator valve for pressure. It consists of a valve spool and a valve body or casing, and an electric solenoid. The valve assembly has three ports and two variable metering orifices, represented by modulated R-elements. They

  19. A modelling study into the effects of variable valve timing on the gas exchange process and performance of a 4-valve DI homogeneous charge compression ignition (HCCI) engine

    Microsoft Academic Search

    A. F. M. Mahrous; A. Potrzebowski; M. L. Wyszynski; H. M. Xu; A. Tsolakis; P. Luszcz

    2009-01-01

    Homogeneous charge compression ignition (HCCI) combustion mode is a relatively new combustion technology that can be achieved by using specially designed cams with reduced lift and duration. The auto-ignition in HCCI engine can be facilitated by adjusting the timing of the exhaust-valve-closing and, to some extent, the timing of the intake-valve-opening so as to capture a proportion of the hot

  20. Standing valve

    SciTech Connect

    Coleman, S.B.

    1990-08-28

    This patent discusses an apparatus for removing fluids from a wellbore. It comprises a valve housing fixedly secured to a wellbore tubing string, the housing having perforations and a valve seating surface; a valve stem alignment guide secured to the valve housing; a valve stem adapted for movement in the valve stem alignment guide; and a valve seating device attached to the valve stem and capable of contacting the valve seating surface, thereby preventing fluid flow through the valve housing and past the valve seating surface when the seating device and valve seating surface are in contact.

  1. Testing the Impact of Job-Related Variables on a Utility Judgment Training Criterion beyond Background and Affective Reaction Variables

    ERIC Educational Resources Information Center

    Blau, Gary; Gibson, Greg; Bentley, Melissa; Chapman, Susan

    2012-01-01

    We tested the incremental impact of a job-related set of variables for explaining a utility judgment training effectiveness variable, that is, course completion skill preparedness, beyond background and course-related variables. Our respondents were two different emergency medical service samples, 415 basics and 742 paramedics, from the 2008 US…

  2. Fuel economy effects and incremental cost, weight and lead time impacts of employing Variable Valve Timing (VVT) engine technology. Summary report

    SciTech Connect

    Spinney, B.

    1997-05-19

    The results of the summary report and the attached contractor study suggest that the incorporation of variable valve timing features into a modern V-6 engine will be fairly costly to the vehicle buyer. However, fuel economy gains will likely be significant over the life of the vehicle. The scope of the project did not include any estimates of the long term benefits that would accrue to vehicle owners through energy conservation. Most important, the cost and weight contained herein is based on a theoretical engine design for which the dimensions are approximate. Hence, the estimates provided below and throughout this report are preliminary only. The $392 retail price increase shown below represents a composite for Chrysler, Ford, and General Motors. The variable valve timing features selected for inclusion in the study are: variable camshaft phasing, long and short event follower cams, and divided air intake runners with a port throttle in one runner. Oil system and variable valve timing system controls plus miscellaneous wiring, clips, painting, plating and assembly labor complete the changes required to incorporate the variable valve timing system into the selected engine design. Estimated retail price and weight increases associated with these changes are presented.

  3. Thickness of the pinned layer as a controlling factor in domain wall formation during training in IrMn-based spin valves

    Microsoft Academic Search

    Jun Park; Shannon M. Watson; C. M. Furjanic; D. K. Draganova; S. D. Eisenberg; D. J. Tighe; P. A. Kienzle; M. J. Carey; J. A. Borchers; P. D. Sparks; J. C. Eckert

    2008-01-01

    Studies of CoFe-based spin valves with antiferromagnetic IrMn layers as thin as 1.6 nm have demonstrated that a domain wall parallel to the surface develops in the pinned layer after training at the magnetoresistance (MR) maximum. To investigate the effects of domain wall formation on the MR, we have studied the depth profile of the vector magnetization in comparable spin

  4. Spray characterization of flex-fuel gasoline DI injectors and spray interaction with charge motion in a variable valve actuation engine

    Microsoft Academic Search

    Atsushi Matsumoto

    2012-01-01

    The objective of this study is to understand the characteristics of GDI sprays and behavior of in-cylinder charge motion in a GDI engine which is equipped with variable valve actuation. High speed spray visualization in a spray chamber was conducted for a study of spray development. By Schlieren visualization technique, the effect of different conditions including ambient conditions (temperature, pressure)

  5. Spray characterization of flex-fuel gasoline di injectors and spray interaction with charge motion in a variable valve actuation engine

    Microsoft Academic Search

    Atsushi Matsumoto

    2012-01-01

    The objective of this study is to understand the characteristics of GDI sprays and behavior of in-cylinder charge motion in a GDI engine which is equipped with variable valve actuation. High speed spray visualization in a spray chamber was conducted for a study of spray development. By Schlieren visualization technique, the effect of different conditions including ambient conditions (temperature, pressure)

  6. Fuel economy effects and incremental cost, weight and lead time impacts of employing Variable Valve Timing (VVT) engine technology. Final report

    Microsoft Academic Search

    D. Patterson; A. Simko; D. Reilly

    1997-01-01

    In recent years, new mechanical inventions and electronic engine controls have made variable valve timing a production possibility. A few manufacturers have VVT systems in production. The report presents a paper study of the fuel economy benefits and the incremental manufacturing costs, tooling costs and engine weights as well as production leadtime for a VVT engine. Emission levels are considered.

  7. Fuel economy effects and incremental cost, weight and lead time impacts of employing Variable Valve Timing (VVT) engine technology. Summary report

    Microsoft Academic Search

    Spinney

    1997-01-01

    The results of the summary report and the attached contractor study suggest that the incorporation of variable valve timing features into a modern V-6 engine will be fairly costly to the vehicle buyer. However, fuel economy gains will likely be significant over the life of the vehicle. The scope of the project did not include any estimates of the long

  8. Variability between methods of calculating mitral valve area: Simultaneous Doppler echocardiographic and cardiac catheterization studies conducted before and after percutaneous mitral valvuloplasty

    Microsoft Academic Search

    Kyle W. Klarich; Charanjit S. Rihal; Rick A. Nishimura

    1996-01-01

    The purpose of this study was to assess the variability of measuring the mitral valve area (MVA) by the cardiac catheterization (Gorlin) method and two Doppler echocardiographic methods, the pressure half-time and continuity equation methods. The determinants of MVA were measured simultaneously before and after percutaneous mitral balloon valvuloplasty (PBMV). Thirty-three patients with severe mitral stenosis underwent simultaneous measurements of

  9. Continuously variable transmission hydraulic control system having two pressure regulating valves

    Microsoft Academic Search

    D. Sawada; M. Sugaya; Y. Soga; R. Imai

    1987-01-01

    A hydraulic control system is described for a continuously variable transmission having first and second variable-diameter pulleys provided on a first and a second shafts, a transmission belt connecting the first and second pulleys to transmit power from one of the first and second pulleys to the other, and a pair of hydraulic cylinders for changing an effective diameter of

  10. Investigation on the characteristics of a new high frequency three-way proportional pressure reducing valve in variable valve system of automobile engine

    Microsoft Academic Search

    Jin-rong Liu; Bo Jin; Ying-jun Xie; Ying Chen; Zhen-tao Weng

    In this study, a new high frequency three way proportional pressure-reducing valve has been developed. By reducing the turns of the coil and using a high speed current amplifier, the responding time of the proportional solenoid is reduced to less than 1 ms. The steady and dynamic analyses show that the output pressure is proportional to the coil current and

  11. The Association Between Vitamin K Antagonist Therapy and Site-specific Cancer Incidence Estimated by Using Heart Valve Replacement as an Instrumental Variable

    PubMed Central

    Ahern, Thomas P.; Pedersen, Lars; Sværke, Claus; Rothman, Kenneth J.; Sørensen, Henrik Toft; Lash, Timothy L.

    2011-01-01

    Earlier studies suggest a protective association between vitamin K antagonist (VKA) anticoagulants and the incidence of cancer. The authors examined the associations between VKA therapy and incidence of 24 site-specific cancers with a Danish population-based cohort study, using heart valve replacement as an instrumental variable. The authors enrolled 9,727 Danish residents who received a replacement heart valve between 1989 and 2006. The heart valve recipients were matched with 95,481 unexposed individuals on age and sex. The authors used the heart valve replacement instrument to estimate rate ratios associating VKA therapy with incidence of the 24 site-specific cancers using Poisson regression models. Direct associations between VKA therapy and incidence of the 24 cancers were estimated in a prescription validation subset. The instrumental variable associations were plotted according to the inverse normal of rank percentile and subjected to semi-Bayes shrinkage adjustment for multiple comparisons. The pattern of associations was consistent with a null-centered Gaussian distribution. No individual cancer site showed a substantial positive or negative association with VKA therapy in the prescription validation subset, the instrumental variable analysis, or the analysis with semi-Bayes adjustment. These results do not support the existing hypothesis that VKA therapy is associated with reduced cancer risk. PMID:22047822

  12. Exercise training in athletes with bicuspid aortic valve does not result in increased dimensions and impaired performance of the left ventricle.

    PubMed

    Stefani, Laura; Galanti, Giorgio; Innocenti, Gabriele; Mercuri, Roberto; Maffulli, Nicola

    2014-01-01

    Background. Bicuspid aortic valve (BAV) is one of the most common congenital heart disease (0.9%-2%) and is frequently found in the athletes and in the general population. BAV can lead to aortic valve dysfunction and to a progressive aortic dilatation. Trained BAV athletes exhibit a progressive enlargement of the left ventricle (LV) compared to athletes with normal aortic valve morphology. The present study investigates the possible relationship between different aortic valve morphology and LV dimensions. Methods. In the period from 2000 to 2011, we investigated a total of 292 BAV subjects, divided into three different groups (210 athletes, 59 sedentaries, and 23 ex-athletes). A 2D echocardiogram exam to classify BAV morphology and measure the standard LV systo-diastolic parameters was performed. The study was conducted as a 5-year follow-up echocardiographic longitudinal and as cross-sectional study. Results. Typical BAV was more frequent in all three groups (68% athletes, 67% sedentaries, and 63% ex-athletes) than atypical. In BAV athletes, the typical form was found in 51% (107/210) of soccer players, 10% (21/210) of basketball players, 10% track and field athletics (20/210), 8% (17/210) of cyclists, 6% (13/210) swimmers, and 15% (32/210) of rugby players and others sport. Despite a progressive enlargement of the LV (P < 0.001) observed during the follow-up study, no statistical differences of the LV morphology and function were evident among the diverse BAV patterns either in sedentary subjects or in athletes. Conclusion. In a large population of trained BAV athletes, with different prevalence of typical and atypical BAV type, there is a progressive nonstatistically significant enlargement of the LV. In any case, the dimensions of the LV remained within normal range. The metabolic requirements of the diverse sport examined in the present investigations do not seem to produce any negative impact in BAV athletes. PMID:24600528

  13. Anthropometric and training variables related to 10km running performance

    Microsoft Academic Search

    P Bale; D Bradbury; E Colley

    1986-01-01

    Sixty male distance athletes were divided into three equal groups according to their personal best time for the 10km run. The runners were measured anthropometrically and each runner completed a detailed questionnaire on his athletic status, training programme and performance. The runners in this study had similar anthropometric and training profiles to other distance runners of a similar standard. The

  14. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training

    PubMed Central

    Stöggl, Thomas; Sperlich, Billy

    2014-01-01

    Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT), “threshold-training” (THR), high-intensity interval training (HIIT) and a combination of these aforementioned concepts known as polarized training (POL). The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes, and cross-country skiers (peak oxygen uptake: (VO2peak): 62.6 ± 7.1 mL·min?1·kg?1) were randomly assigned to one of four groups performing over 9 weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml·min·kg?1 or 11.7%, P < 0.001), time to exhaustion during the ramp protocol (+17.4%, P < 0.001) and peak velocity/power (+5.1%, P < 0.01). Velocity/power at 4 mmol·L?1 increased after POL (+8.1%, P < 0.01) and HIIT (+5.6%, P < 0.05). No differences in pre- to post-changes of work economy were found between the groups. Body mass was reduced by 3.7% (P < 0.001) following HIIT, with no changes in the other groups. With the exception of slight improvements in work economy in THR, both HVT and THR had no further effects on measured variables of endurance performance (P > 0.05). Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables. PMID:24550842

  15. Method of operating a two-stroke-cycle engine with variable valve timing in a four-stroke-cycle mode

    Microsoft Academic Search

    Richeson

    1992-01-01

    This patent describes a method of operating an internal combustion engine of the type comprising a piston reciprocable in a cylinder, intake port means for admitting air into the cylinder, an exhaust valve that is opened and closed by valve actuator means independent of crankshaft position, spark ignition means, and fuel injection means. It comprises a first stroke wherein the

  16. Effects of dynamic resistance training on heart rate variability in healthy older women

    Microsoft Academic Search

    Roberta Forte; Giuseppe De Vito; Francesco Figura

    2003-01-01

      \\u000a Twenty healthy women aged between 65 and 74 years, trained three times a week, for 16 weeks, on a cycle ergometer, to determine\\u000a the effects of dynamic resistance training on heart rate variability (HRV). Subjects were allocated to two training groups,\\u000a high (HI, n=10) and low (LO, n=10) intensity. The HI group performed eight sets of 8 revolutions at 80% of the

  17. Continuously variable transmission hydraulic control system having two pressure regulating valves

    SciTech Connect

    Sawada, D.; Sugaya, M.; Soga, Y.; Imai, R.

    1987-08-11

    A hydraulic control system is described for a continuously variable transmission having first and second variable-diameter pulleys provided on a first and a second shafts, a transmission belt connecting the first and second pulleys to transmit power from one of the first and second pulleys to the other, and a pair of hydraulic cylinders for changing an effective diameter of the pulleys engaging the belt. The hydraulic control system consists of: a hydraulic source delivering a pressurized fluid; a first pressure regulating device for regulating the pressurized fluid to apply a first line pressure to one of the hydraulic cylinders for controlling a tension of the transmission belt; flow control means for controlling flow of the fluid into the other hydraulic cylinder and flow of the fluid from the other hydraulic cylinder, thereby changing the effective diameters of the pulleys to vary a speed ratio of the transmission; a second pressure regulating device provided between the hydraulic source and the first pressure regulating device, and regulating the pressurized fluid to apply a second line pressure to the flow control means, the second line pressure being higher than a pressure in the other hydraulic cylinder or the first line pressure by a predetermined value; and releasing means for releasing the second pressure regulating device from its pressure regulating operation while the speed ratio of the transmission is changed with the fluid discharged from the other hydraulic cylinder, or while the speed ratio is held constant.

  18. Manipulating Resistance Training Program Variables to Optimize Maximum Strength in Men: A Review

    Microsoft Academic Search

    TAN BENEDICT

    1999-01-01

    Maximum strength is the capacity to generate force within an isometric contraction. It is a valuable attribute to most athletes because it acts as a general base that supports spe- cific training in other spheres of conditioning. Resistance training program variables can be manipulated to specifi- cally optimize maximum strength. After deciding on the ex- ercises appropriate for the sport,

  19. Prediction of advanced level aviation performance criteria from early training and selection variables

    Microsoft Academic Search

    Ronald M. Bale; George M. Rickus; Rosalie K. Ambler

    1973-01-01

    Considers the prediction problem in the case of designated aviators who are not successful in the replacement air group (RAG), or postgraduate, phase of instruction. The sample group consisted of 592 naval jet aviators assigned to RAG training in East and West Coast squadrons. Employing multiple correlation analysis to examine RAG completion as a remote criterion variable, undergraduate training grades

  20. EFFECTS OF VARIABLE-PRIORITY TRAINING ON AUTOMATION-RELATED COMPLACENCY: PERFORMANCE AND EYE MOVEMENTS

    E-print Network

    Parasuraman, Raja

    2-346 EFFECTS OF VARIABLE-PRIORITY TRAINING ON AUTOMATION-RELATED COMPLACENCY: PERFORMANCE AND EYE in reducing automation-related complacency was examined. Participants were trained under one of three). They subsequently monitored an automated system while simultaneously performidg tracking and fuel management tasks

  1. Bias and variability of diagnostic spectral parameters extracted from closing sounds produced by bioprosthetic valves implanted in the mitral position.

    PubMed

    Cloutier, G; Durand, L G; Guardo, R; Sabbah, H N; Stein, P D

    1989-08-01

    A method is proposed to estimate the bias and variability of eight diagnostic spectral parameters extracted from mitral closing sounds produced by bioprosthetic heart valves. These spectral parameters are: the frequency of the dominant (F1) and second dominant (F2) spectral peaks, the highest frequency of the spectrum found at -3 dB (F-3), -10 dB (F-10) and -20 dB (F-20) below the highest peak, the relative integrated area above -20 dB of the dominant peak (RIA20), the bandwidth at -3 dB of the dominant spectral peak (BW3), and the ratio of F1 divided by BW3 (Q1). The bias and variability of four spectral techniques were obtained by comparing parameters extracted from each technique with the parameters of a spectral "standard." This "standard" consisted of 19 normal mitral sound spectra computed analytically by evaluating the Z transform of a sum of decaying sinusoids on the unit circle. Truncation of the synthesized mitral signals and addition of random noise were used to simulate the physiological characteristics of the closing sounds. Results show that the fast Fourier transform method with rectangular window provides the best estimates of F1 and Q1, that the Steiglitz-McBride method with maximum entropy (pole-zero modeling with four poles and four zeros) can best evaluate F2, F-20, RIA20 and BW3, and that the all-pole modeling with covariance method (16 poles) is best suited to compute F-3. It was also shown that both the all-pole modeling and the Steiglitz-McBride methods can be used to estimate F-10. It is concluded that a single algorithm would not provide the best estimates of all spectral parameters. PMID:2759640

  2. Physics-based closed-loop control of phasing, peak pressure and work output in HCCI engines utilizing variable valve actuation

    Microsoft Academic Search

    Gregory M. Shaver; J. Christian Gerdes; Matthew Roelle

    2004-01-01

    Homogeneous charge compression ignition (HCCI) represents a promising combustion strategy for future engines. However, HCCI lacks an easily identified combustion trigger and, when achieved via variable valve actuation (VVA), includes cycle-to-cycle coupling through the exhaust gas. This makes controlling the process decidedly non-trivial. To address these issues, the development of a closed-loop controller for HCCI combustion phasing and peak pressure

  3. Visuospatial Ability Factors and Performance Variables in Laparoscopic Simulator Training

    ERIC Educational Resources Information Center

    Luursema, Jan-Maarten; Verwey, Willem B.; Burie, Remke

    2012-01-01

    Visuospatial ability has been shown to be important to several aspects of laparoscopic performance, including simulator training. Only a limited subset of visuospatial ability factors however has been investigated in such studies. Tests for different visuospatial ability factors differ in stimulus complexity, in their emphasis on identifying…

  4. Flow control valve

    SciTech Connect

    Szlaga, E.

    1989-02-21

    This patent describes a flow-metering pressure-relief valve assembly for vehicle fuel tanks and the like, the assembly comprising a valve housing having an interior wall configured to define a chamber, inlet opening means for admitting fuel vapor into the chamber, and outlet opening means for exhausting fuel vapor from the chamber, the interior wall providing a first flow-metering surface situated in close proximity to the outlet opening means, a valve seat attached to the valve housing and situated in the chamber to surround the inlet opening means, a pressure-relief element in the chamber, the pressure-relief element including a valve member having an inner surface confronting the inlet means, and an upstanding skirt attached to the valve member and having a distal portion extending in an outward direction toward the outlet means in spaced relation to the interior wall of the valve housing, the distal portion providing a second flow-metering surface which cooperates with the first flow-metering surface to define a variable flow-metering orifice therebetween, and biasing means for yieldably biasing the valve member against the valve seat.

  5. Effect of exercise training on heart rate variability in healthy older adults

    Microsoft Academic Search

    Phyllis K. Stein; Ali A. Ehsani; Peter P. Domitrovich; Robert E. Kleiger; Jeffrey N. Rottman

    1999-01-01

    Objective To determine the effect of exercise training on cardiac autonomic modulation in normal older adults by using analysis of heart rate variability. Subjects The exercise group consisted of 7 men and 9 women aged 66 ± 4 years. The comparison group consisted of 7 men and 9 women also aged 66 ± 4 years. Method Heart rate variability was

  6. Increasing Response Variability of Mand Frames with Script Training and Extinction

    ERIC Educational Resources Information Center

    Betz, Alison M.; Higbee, Thomas S.; Kelley, Kristen N.; Sellers, Tyra P.; Pollard, Joy S.

    2011-01-01

    Children with autism often demonstrate less variable behavior than their typically developing peers and those with other cognitive disabilities. A possible reason for lack of response variability emitted by children with autism is that they do not have a variety of response forms in their repertoire. Multiple-exemplar training through the use of…

  7. Plug valve

    DOEpatents

    Wordin, John J. (Shelley, ID)

    1989-01-01

    An improved plug valve wherein a novel shape for the valve plug and valve chamber provide mating surfaces for improved wear characteristics. The novel shape of the valve plug is a frustum of a body of revolution of a curved known as a tractrix, a solid shape otherwise known as a peudosphere.

  8. A new type of electro-hydraulic control valve structure

    Microsoft Academic Search

    Minyong Tong

    2012-01-01

    The solution to eliminate the conflict between engine fuel economy and emissions performance has been the key to the development of engine technology, and engine variable valve timing technology is raised by one of the options. Development of variable valve technology in the world is introduced. According to variation of valve control parameters, variable valve technology is classified in detail.

  9. Space Vehicle Valve System

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R. (Inventor); Lindner, Jeffrey L. (Inventor)

    2014-01-01

    The present invention is a space vehicle valve system which controls the internal pressure of a space vehicle and the flow rate of purged gases at a given internal pressure and aperture site. A plurality of quasi-unique variable dimension peaked valve structures cover the purge apertures on a space vehicle. Interchangeable sheet guards configured to cover valve apertures on the peaked valve structure contain a pressure-activated surface on the inner surface. Sheet guards move outwardly from the peaked valve structure when in structural contact with a purge gas stream flowing through the apertures on the space vehicle. Changing the properties of the sheet guards changes the response of the sheet guards at a given internal pressure, providing control of the flow rate at a given aperture site.

  10. Promoting Response Variability and Stimulus Generalization in Martial Arts Training

    ERIC Educational Resources Information Center

    Harding, Jay W.; Wacker, David P.; Berg, Wendy K.; Rick, Gary; Lee, John F.

    2004-01-01

    The effects of reinforcement and extinction on response variability and stimulus generalization in the punching and kicking techniques of 2 martial arts students were evaluated across drill and sparring conditions. During both conditions, the students were asked to demonstrate different techniques in response to an instructor's punching attack.…

  11. Individual aptitude in Mandarin lexical tone perception predicts effectiveness of high-variability training

    PubMed Central

    Sadakata, Makiko; McQueen, James M.

    2014-01-01

    Although the high-variability training method can enhance learning of non-native speech categories, this can depend on individuals’ aptitude. The current study asked how general the effects of perceptual aptitude are by testing whether they occur with training materials spoken by native speakers and whether they depend on the nature of the to-be-learned material. Forty-five native Dutch listeners took part in a 5-day training procedure in which they identified bisyllabic Mandarin pseudowords (e.g., asa) pronounced with different lexical tone combinations. The training materials were presented to different groups of listeners at three levels of variability: low (many repetitions of a limited set of words recorded by a single speaker), medium (fewer repetitions of a more variable set of words recorded by three speakers), and high (similar to medium but with five speakers). Overall, variability did not influence learning performance, but this was due to an interaction with individuals’ perceptual aptitude: increasing variability hindered improvements in performance for low-aptitude perceivers while it helped improvements in performance for high-aptitude perceivers. These results show that the previously observed interaction between individuals’ aptitude and effects of degree of variability extends to natural tokens of Mandarin speech. This interaction was not found, however, in a closely matched study in which native Dutch listeners were trained on the Japanese geminate/singleton consonant contrast. This may indicate that the effectiveness of high-variability training depends not only on individuals’ aptitude in speech perception but also on the nature of the categories being acquired. PMID:25505434

  12. Wellhead valve

    SciTech Connect

    Smith, J.D.

    1989-05-02

    A wellhead valve is described for use within a wellhead comprising a tubular body having a central passage therethrough with a downwardly facing valve seat surrounding a portion of the central passageway, internal threads, external threads and a cylindrical sealing surface above the valve seat, a valve member mounted within the central passage below the valve seat and adapted to more axially therein to close flow through the valve seat, means biasing the valve member into engagement with the valve seat, a plug threaded into the central passage internal threads and having sealing means for sealing against the cylindrical sealing surface in the passage; and a projection extending axially within the passage between the sealing means and the valve member, the plug adapted to be positioned in an upper position within the passage with its sealing means in sealing engagement with the cylindrical sealing surface to prevent flow through the passage, the plug being positionable lower than the upper position in a first lower position in the passage with the sealing means out of sealing engagement with the cylindrical sealing surface to allow the valve member to be operative as a back pressure valve, the plug being positionable lower than the first lower position in the passage with the sealing means out of sealing engagement with the cylindrical sealing surface and engaging the valve member to hold the valve member out engagement with its valve seat to allow flow through the passage.

  13. Check valve

    DOEpatents

    Upton, Hubert Allen (Morgan Hill, CA); Garcia, Pablo (Stanford, CA)

    1999-08-24

    A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion.

  14. Check valve

    DOEpatents

    Upton, H.A.; Garcia, P.

    1999-08-24

    A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs.

  15. Differences in Acceleration Training and Exercise Training on Resting Cardiovascular Variables

    NASA Technical Reports Server (NTRS)

    Evans, J. M.; Simonson, S. R.; Knapp, C. F.; Stocks, J. M.; Biagini, H. W.; Cowell, S. A.; Bailey, Kn. N.; Vener, J. M.; Evetts, S. N.; Dalton, Bonnie P. (Technical Monitor)

    2000-01-01

    The relative effects of alternating exercise vs. acclamation training an mean blood pressure (BP, Finapres), cardiac output (CO, BoMed) and peripheral resistance (PR, calculated) were evaluated. Six healthy men (33$\\pm$(SD)6 yr. 178$\\pm$4 cm, 86$\\pm$6 kg) underwent exercise training (ET, n=3): supine on a cycle ergometer (40 to 90\\% Vo$_{2}$ max) during exposure to constant+1G$_{z}$ for $\\sim$30 min/day for 14 days on NASA's 1.9m Human Powered Centrifuge (HPC). They also underwent oscillatory (between +1 G$ {z}$and$\\sim$2.5G$_{z}$) acceleration training (AT, n=3) for $\\sim$30 min/day for 14 days on the HPC. After four weeks of ambulatory deconditioning, training protocols were switched. AT increased resting CO by 9.MpmS(SE)3.2\\% (p$less than$0.05) with no effect on BF, and ET decreased BP by 9.2$\\pm$4.6\\% (p$less than$0.08) as well as spectral power of PR by 41$\\pm$9\\% (p$less than$0.05). The major effect of acceleration training was to increase resting cardiac output while that of exercise mining was to decrease resting blood pressure.

  16. Variable Valve Actuation

    Microsoft Academic Search

    Jeffrey Gutterman; A. J. Lasley

    2008-01-01

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release

  17. Supercharged two-cycle engines employing novel single element reciprocating shuttle inlet valve mechanisms and with a variable compression ratio

    NASA Technical Reports Server (NTRS)

    Wiesen, Bernard (Inventor)

    2008-01-01

    This invention relates to novel reciprocating shuttle inlet valves, effective with every type of two-cycle engine, from small high-speed single cylinder model engines, to large low-speed multiple cylinder engines, employing spark or compression ignition. Also permitting the elimination of out-of-phase piston arrangements to control scavenging and supercharging of opposed-piston engines. The reciprocating shuttle inlet valve (32) and its operating mechanism (34) is constructed as a single and simple uncomplicated member, in combination with the lost-motion abutments, (46) and (48), formed in a piston skirt, obviating the need for any complex mechanisms or auxiliary drives, unaffected by heat, friction, wear or inertial forces. The reciprocating shuttle inlet valve retains the simplicity and advantages of two-cycle engines, while permitting an increase in volumetric efficiency and performance, thereby increasing the range of usefulness of two-cycle engines into many areas that are now dominated by the four-cycle engine.

  18. Inter-individual variability in the adaptation of human muscle specific tension to progressive resistance training

    Microsoft Academic Search

    Robert M. ErskineDavid; David A. Jones; Alun G. Williams; Claire E. Stewart; Hans Degens

    2010-01-01

    Considerable variation exists between people in the muscle response to resistance training, but there are numerous ways muscle\\u000a might adapt to overload that might explain this variable response. Therefore, the aim of this study was to quantify the range\\u000a of responses concerning the training-induced change in maximum voluntary contraction (MVC) knee joint torque, quadriceps femoris\\u000a (QF) maximum muscle force (F),

  19. Method of operating a two-stroke-cycle engine with variable valve timing in a four-stroke-cycle mode

    SciTech Connect

    Richeson, W.E.

    1992-07-21

    This patent describes a method of operating an internal combustion engine of the type comprising a piston reciprocable in a cylinder, intake port means for admitting air into the cylinder, an exhaust valve that is opened and closed by valve actuator means independent of crankshaft position, spark ignition means, and fuel injection means. It comprises a first stroke wherein the piston moves from BDC to TDC, a second stroke wherein the piston moves from TDC to BDC, a third stroke wherein the piston moves from BDC to TDC, a fourth stroke wherein the piston moves from TDC to BDC.

  20. [Voluntary alpha-power increasing training impact on the heart rate variability].

    PubMed

    Bazanova, O M; Balioz, N V; Muravleva, K B; Skoraia, M V

    2013-01-01

    In order to study the effect of the alpha EEG power increasing training at heart rate variability (HRV) as the index of the autonomic regulation of cognitive functions there were follow tasks: (1) to figure out the impact of biofeedback in the voluntary increasing the power in the individual high-frequency alpha-band effect on heart rate variability and related characteristics of cognitive and emotional spheres, (2) to determine the nature of the relationship between alpha activity indices and heart rate variability, depending on the alpha-frequency EEG pattern at rest (3) to examine how the individual alpha frequency EEG pattern is reflected in changes HRV as a result of biofeedback training. Psychometric indicators of cognitive performance, the characteristics of the alpha-EEG activity and heart rate variability (HRV) as LF/HF and pNN50 were recorded in 27 healthy men aged 18-34 years, before, during, and after 10 sessions of training of voluntary increase in alpha power in the individual high-frequency alpha band with eyes closed. To determine the biofeedback effect on the alpha power increasing training, data subjects are compared in 2 groups: experimental (14) with the real and the control group (13 people)--with mock biofeedback. The follow up effect of trainings was studied through month over the 10 training sessions. Results showed that alpha biofeedback training enhanced the fluency and accuracy in cognitive performance, decreased anxiety and frontal EMG, increased resting frequency, width and power in individual upper alpha range only in participants with low baseline alpha frequency. While mock biofeedback increased resting alpha power only in participants with high baseline resting alpha frequency and did change neither cognitive performance, nor HRV indices. Biofeedback training eliminated the alpha power decrease in response to arithmetic task in both with high and low alpha frequency participants and this effect was followed up over the month. Mock biofeedback training has no such effect. The positive correlation between the alpha-peak frequency and pNN50 in patients with initially low, but negative--those with high baseline alpha frequency explains the multidirectional biofeedback effects on HRV in low and high alpha frequency subjects. The individual alpha-frequency EEG pattern determines the effectiveness of the alpha EEG biofeedback training in changing heart rate variability, which provides a basis for predicting the results and develop individual approaches to the biofeedback technology implementation that can be used in clinical practice for treatment and rehabilitation of psychosomatic syndromes and in educational training. PMID:23668077

  1. Gas lift valve

    SciTech Connect

    Decker, K.L.

    1991-11-19

    This patent describes a gas lift device for controlling the flow of gas between the exterior and the interior of a well tubing. It comprises body means, the body means having inlet means, an outlet, a flow course extending between the inlet means and the outlet, means on the body for attachment to means for securing the same to the well tubing; main valve means; a main chamber in the body means for containing a volume of compressible liquid; pilot valve means in the body means between the main chamber and the main valve means, the pilot valve means including a variable volume chamber for containing a compressible liquid, a restricted fluid passage for fluidly communicating the variable volume chamber with the main chamber, and pressure responsive means for moving the pilot valve means from a closed position to an open position responsive to a differential pressure across the pressure responsive means from a closed position to an open position responsive to a differential pressure across the pressure responsive means as a result of an increase in pressure exterior of the well tubing for controlling admission of fluid pressure from the exterior of the tubing to the pressure responsive area of the main valve member for moving the same to open position; and means for sealing between the main valve and the body.

  2. Independent factors associated with longevity of prosthetic pulmonary valves and valved conduits

    Microsoft Academic Search

    Christopher A Caldarone; Brian W McCrindle; Glen S Van Arsdell; John G Coles; Gary Webb; Robert M Freedom; William G Williams

    2000-01-01

    Objective: To evaluate the age dependence of variables predictive of pulmonary valve prosthesis replacement, we conducted the following analysis. Methods: Retrospective analysis of 945 operations in 726 patients undergoing placement of pulmonary valve prostheses was performed. Age was identified as a strong independent predictor of valve failure. The database was stratified into age-based subsets and predictors of valve replacement were

  3. Anthropometric and training variables related to half-marathon running performance in recreational female runners.

    PubMed

    Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rosemann, Thomas

    2011-05-01

    The relationship between skin-fold thickness and running has been investigated in distances ranging from 100 m to the marathon distance (42.195 km), with the exclusion of the half-marathon distance (21.0975 km). We investigated the association between anthropometric variables, prerace experience, and training variables with race time in 42 recreational, nonprofessional, female half-marathon runners using bi- and multivariate analysis. Body weight (r, 0.60); body mass index (r, 0.48); body fat percentage (r, 0.56); pectoral (r, 0.61), mid-axilla (r, 0.69), triceps (r, 0.49), subscapular (r, 0.61), abdominal (r, 0.59), suprailiac (r, 0.55), and medial calf (r, 0.53) skin-fold thickness; mean speed of the training sessions (r, -0.68); and personal best time in a half-marathon (r, 0.69) correlated with race time after bivariate analysis. Body weight (P = 0.0054), pectoral skin-fold thickness (P = 0.0068), and mean speed of the training sessions (P = 0.0041) remained significant after multivariate analysis. Mean running speed during training was related to mid-axilla (r, -0.31), subscapular (r, -0.38), abdominal (r, -0.44), and suprailiac (r, -0.41) skin-fold thickness, the sum of 8 skin-fold thicknesses (r, -0.36); and percent body fat (r, -0.31). It was determined that variables of both anthropometry and training were related to half-marathon race time, and that skin-fold thicknesses were associated with running speed during training. For practical applications, high running speed during training (as opposed to extensive training) may both reduce upper-body skin-fold thicknesses and improve race performance in recreational female half-marathon runners. PMID:21673497

  4. Rotary valve

    SciTech Connect

    Rohlfing, R.G.; Norwood, D.D.

    1988-09-27

    This patent describes a method of controlling the passage of material through a structure of the type which includes valve body means defining a valve chamber and having an inlet port and an outlet port each communicating between the valve chamber and the exterior of the valve body means; annular inlet seal means in the valve chamber and having an inlet passage therethrough communicating in seal engagement with the inlet port; annular outlet seal means in the valve chamber and having an outlet passage therethrough communicating in sealing engagement with the outlet port; valve member means for controlling the passage of material through the valve body means. The valve member means having a frustoconically shaped outer surface and being disposed within the valve chamber with the frustoconically shaped outer surface in close slidable sealing engagement with the annular outlet seal means and being adapted to rotate about its longitudinal axis within the valve chamber; the method comprising the steps of: (a) introducing fluid generally transversely into the inlet port at a point upstream of the annular inlet seal means; (b) supplying material to the inlet port upstream of the point of introduction of the fluid; and (c) rotating the valve member means relative to the valve body means to block flow of the material and the introduced fluid through the valve body means from the inlet port, and, alternately, to permit flow of the material and the introduced fluid into the valve body means via the inlet port and out of the valve body means via the outlet port.

  5. Venous Valves

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2009-11-20

    This simple FlashTM animation depicts the function of a venous valve. It is shown in the context of a transverse section. During systole corpuscles are shown flowing through the open valve. As the pressure reverses during diastole, the valve closes and back flow is blocked.

  6. Moderating variables of music training-induced neuroplasticity: a review and discussion.

    PubMed

    Merrett, Dawn L; Peretz, Isabelle; Wilson, Sarah J

    2013-01-01

    A large body of literature now exists to substantiate the long-held idea that musicians' brains differ structurally and functionally from non-musicians' brains. These differences include changes in volume, morphology, density, connectivity, and function across many regions of the brain. In addition to the extensive literature that investigates these differences cross-sectionally by comparing musicians and non-musicians, longitudinal studies have demonstrated the causal influence of music training on the brain across the lifespan. However, there is a large degree of inconsistency in the findings, with discordance between studies, laboratories, and techniques. A review of this literature highlights a number of variables that appear to moderate the relationship between music training and brain structure and function. These include age at commencement of training, sex, absolute pitch (AP), type of training, and instrument of training. These moderating variables may account for previously unexplained discrepancies in the existing literature, and we propose that future studies carefully consider research designs and methodologies that control for these variables. PMID:24058353

  7. Effect of Training on Physiological and Biochemical Variables of Soccer Players of Different Age Groups

    PubMed Central

    Manna, Indranil; Khanna, Gulshan Lal; Chandra Dhara, Prakash

    2010-01-01

    Purpose To find out the effect of training on selected physiological and biochemical variables of Indian soccer players of different age groups. Methods A total of 120 soccer players volunteered for the study, were divided (n = 30) into 4 groups: (i) under 16 years (U16), (ii) under 19 years (U19), (iii) under 23 years (U23), (iv) senior (SR). The training sessions were divided into 2 phases (a) Preparatory Phase (PP, 8 weeks) and (b) Competitive Phase (CP, 4 weeks). The training program consisted of aerobic, anaerobic and skill development, and were completed 4 hrs/day; 5 days/week. Selected physiological and biochemical variables were measured at zero level (baseline data, BD) and at the end of PP and CP. Results A significant increase (P < 0.05) in lean body mass (LBM), VO2max, anaerobic power, grip and back strength, urea, uric acid and high density lipoprotein cholesterol (HDL-C); and a significant decrease (P < 0.05) in body fat, hemoglobin (Hb), total cholesterol (TC), triglyceride (TG) and low density lipoprotein cholesterol (LDL-C) were detected in some groups in PP and CP phases of the training when compare to BD. However, no significant change was found in body mass and maximal heart rate of the players after the training program. Conclusion This study would provide useful information for training and selection of soccer players of different age groups. PMID:22375187

  8. Training the max-margin sequence model with the relaxed slack variables.

    PubMed

    Niu, Lingfeng; Wu, Jianmin; Shi, Yong

    2012-09-01

    Sequence models are widely used in many applications such as natural language processing, information extraction and optical character recognition, etc. We propose a new approach to train the max-margin based sequence model by relaxing the slack variables in this paper. With the canonical feature mapping definition, the relaxed problem is solved by training a multiclass Support Vector Machine (SVM). Compared with the state-of-the-art solutions for the sequence learning, the new method has the following advantages: firstly, the sequence training problem is transformed into a multiclassification problem, which is more widely studied and already has quite a few off-the-shelf training packages; secondly, this new approach reduces the complexity of training significantly and achieves comparable prediction performance compared with the existing sequence models; thirdly, when the size of training data is limited, by assigning different slack variables to different microlabel pairs, the new method can use the discriminative information more frugally and produces more reliable model; last but not least, by employing kernels in the intermediate multiclass SVM, nonlinear feature space can be easily explored. Experimental results on the task of named entity recognition, information extraction and handwritten letter recognition with the public datasets illustrate the efficiency and effectiveness of our method. PMID:22717449

  9. Relation between heart rate variability and training load in middle-distance runners

    Microsoft Academic Search

    Vincent PICHOT; Jean-Michel GASPOZ; Franck ENJOLRAS; Anestis ANTONIADIS; Pascal MININI; Thierry BUSSO

    2000-01-01

    V. PICHOT, F. ROCHE, J. M. GASPOZ, F. ENJOLRAS, A. ANTONIADIS, P. MININI, F. COSTES, T. BUSSO, J. R. LACOUR, and J. C. BARTHELEMY. Relation between heart rate variability and training load in middle-distance runners. Med. Sci. Sports Exerc., Vol. 32, No. 10, pp. 1729-1736, 2000. Purpose: Monitoring physical performance is of major importance in competitive sports. Indices commonly used,

  10. Fast valve

    DOEpatents

    Van Dyke, William J. (Grafton, VA)

    1992-01-01

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

  11. Fast valve

    DOEpatents

    Van Dyke, W.J.

    1992-04-07

    A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

  12. Model-based predictive control of an Electro-Pneumatic exhaust valve for Internal Combustion engines

    Microsoft Academic Search

    Jia Ma; Guoming Zhu; Andrew Hartsig; Harold Schock

    2008-01-01

    Variable valve actuation of internal combustion (IC) engines is capable of significantly improving their performance. Variable valve actuation can be divided into two main categories: variable valve timing with cam shaft(s) and camless valve actuation. For camless valve actuation, research has been centered in electro-magnetic, electro-hydraulic, and electro-pneumatic valve actuators. This research studies the control of the electro-pneumatic valve actuator.

  13. Airborne asbestos exposures associated with gasket and packing replacement: a simulation study of flange and valve repair work and an assessment of exposure variables.

    PubMed

    Madl, Amy K; Devlin, Kathryn D; Perez, Angela L; Hollins, Dana M; Cowan, Dallas M; Scott, Paul K; White, Katherine; Cheng, Thales J; Henshaw, John L

    2015-02-01

    A simulation study was conducted to evaluate worker and area exposure to airborne asbestos associated with the replacement of asbestos-containing gaskets and packing materials from flanges and valves and assess the influence of several variables previously not investigated. Additionally, potential of take home exposures from clothing worn during the study was characterized. Our data showed that product type, ventilation type, gasket location, flange or bonnet size, number of flanges involved, surface characteristics, gasket surface adherence, and even activity type did not have a significant effect on worker exposures. Average worker asbestos exposures during flange gasket work (PCME=0.166 f/cc, 12-59 min) were similar to average worker asbestos exposures during valve overhaul work (PCME=0.165 f/cc, 7-76 min). Average 8-h TWA asbestos exposures were estimated to range from 0.010 to 0.062 f/cc. Handling clothes worn during gasket and packing replacement activities demonstrated exposures that were 0.71% (0.0009 f/cc 40-h TWA) of the airborne asbestos concentration experienced during the 5 days of the study. Despite the many variables considered in this study, exposures during gasket and packing replacement occur within a relatively narrow range, are below current and historical occupational exposure limits for asbestos, and are consistent with previously published data. PMID:25445297

  14. Nonlinear Regulation of Electromagnetic Valves for Camless Engines

    Microsoft Academic Search

    S. Di Gennaro; B. Castillo Toledo; M. D. Di Benedetto

    2006-01-01

    Conventional internal combustion engines use mechanical camshafts to command the opening and closing phases of the intake and exhaust valves. The lift valve profile is designed to reach a good compromise among various requirements of the engine operating conditions. In principle, optimality in every engine condition can be attained by camless valve trains. In this context, electromagnetic valves offer an

  15. Heart valve surgery - discharge

    MedlinePLUS

    Aortic valve replacement - discharge; Aortic valvuloplasty - discharge; Aortic valve repair - discharge; Replacement - aortic valve - discharge; Repair - aortic valve - discharge; Ring annuloplasty - ...

  16. Interactive Effects of Environmental Variability and Military Training on Stream Biota of Three Headwater Drainages in Western Louisiana

    Microsoft Academic Search

    Lance R. Williams; Timothy H. Bonner; James D. Hudson III; Marsha G. Williams; Tracy R. Leavy; Casey S. Williams

    2005-01-01

    We collected fishes and macroinvertebrates seasonally from eight headwater streams in three different drainage basins (the Red, Calcasieu, and Sabine rivers) crossing Peason Ridge Training Area in west-central Louisiana. Peason Ridge is part of the Fort Polk military training facility. We used multivariate analyses to test the effects of physical variables (i.e., current velocity, depth, and substrate), time (seasonal variability),

  17. Flow metering valve

    DOEpatents

    Blaedel, K.L.

    1983-11-03

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  18. Flow metering valve

    DOEpatents

    Blaedel, Kenneth L. (Dublin, CA)

    1985-01-01

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  19. Drain valve

    SciTech Connect

    Koller, F.G.

    1989-11-14

    This patent describes a lightning-protected fuel drain valve. It comprises means forming a non-conductive plastic housing connectable to a fuel tank and having a port opening exteriorly of the housing and the fuel tank, a non-conductive plastic valve member guided for movement along an axis extending through the housing and the port between a first position wherein a lower end portion thereof closes the port and a second position wherein the lower end portion is raised to open the port. It has bias means operatively engaged with the valve member to bias the valve member in a direction along the axis that would extend the valve member downwardly of the port and the housing, cooperating stop means connected with the valve member for movement therewith and first abutment means fixed relative to the housing for preventing to the valve member from passing downwardly out of the port, second abutment means fixed to the housing in confronting relation to the first abutment means and cooperating with the stop means for preventing the valve member from moving upwardly along the axis by a distance sufficient that the outer end portion moves away from the port to open the same unless the valve member is first rotated about the axis to maintain the valve member in a port-closed position in the event of a lightning strike.

  20. Depressurization valve

    DOEpatents

    Skoda, G.I.

    1989-03-28

    A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring-preferably of the Belleville variety-acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion.

  1. Heart rate variability in elite triathletes, is variation in variability the key to effective training? A case comparison.

    PubMed

    Plews, Daniel J; Laursen, Paul B; Kilding, Andrew E; Buchheit, Martin

    2012-11-01

    Measures of an athlete's heart rate variability (HRV) have shown potential to be of use in the prescription of training. However, little data exists on elite athletes who are regularly exposed to high training loads. This case study monitored daily HRV in two elite triathletes (one male: 22 year, VO2max 72.5 ml kg min(-1); one female: 20 year, VO2max 68.2 ml kg min(-1)) training 23 ± 2 h per week, over a 77-day period. During this period, one athlete performed poorly in a key triathlon event, was diagnosed as non-functionally over-reached (NFOR) and subsequently reactivated the dormant virus herpes zoster (shingles). The 7-day rolling average of the log-transformed square root of the mean sum of the squared differences between R-R intervals (Ln rMSSD), declined towards the day of triathlon event (slope = -0.17 ms/week; r2 = -0.88) in the NFOR athlete, remaining stable in the control (slope = 0.01 ms/week; r2 = 0.12). Furthermore, in the NFOR athlete, coefficient of variation of HRV (CV of Ln rMSSD 7-day rolling average) revealed large linear reductions towards NFOR (i.e., linear regression of HRV variables versus day number towards NFOR: -0.65%/week and r2 = -0.48), while these variables remained stable for the control athlete (slope = 0.04%/week). These data suggest that trends in both absolute HRV values and day-to-day variations may be useful measurements indicative of the progression towards mal-adaptation or non-functional over-reaching. PMID:22367011

  2. Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners.

    PubMed

    Vesterinen, V; Häkkinen, K; Hynynen, E; Mikkola, J; Hokka, L; Nummela, A

    2013-03-01

    The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV, and serum hormone concentrations were measured before and after both training periods in 28 recreational endurance runners. During the study peak treadmill running speed (Vpeak ) improved by 7.5 ± 4.5%. No changes were observed in HRV indices after BTP, but after ITP, these indices increased significantly (HFP: 1.9%, P=0.026; TP: 1.7%, P=0.007). Significant correlations were observed between the change of Vpeak and HRV indices (TP: r=0.75, P<0.001; HFP: r=0.71, P<0.001; LFP: r=0.69, P=0.01) at baseline during ITP. In order to lead to significant changes in HRV among recreational endurance runners, it seems that moderate- and high-intensity training are needed. This study showed that recreational endurance runners with a high HRV at baseline improved their endurance running performance after ITP more than runners with low baseline HRV. PMID:21812828

  3. Flapper valve

    SciTech Connect

    Ross, M.S.

    1989-10-03

    In a fluid catalytic cracking unit including a cracking riser, a reactor vessel at the top of the cracking riser, a regenerator and at least one cyclone separator for separating cracking catalyst from gases. The separator having a dependent dipleg which has at its lower end a flapper valve for retaining catalyst in the dipleg. The improvement described in this patent comprising a flapper valve having a movable support member, a valve seat member, a valve body member, and an upstanding annular retaining ring.

  4. The Effects of Basic Gymnastics Training Integrated with Physical Education Courses on Selected Motor Performance Variables

    ERIC Educational Resources Information Center

    Alpkaya, Ufuk

    2013-01-01

    The purpose of this study is to determine the influence of gymnastics training integrated with physical education courses on selected motor performance variables in seven year old girls. Subjects were divided into two groups: (1) control group (N=15, X=7.56 plus or minus 0.46 year old); (2) gymnastics group (N=16, X=7.60 plus or minus 0.50 year…

  5. Extremum Seeking Control for Soft Landing of an Electromechanical Valve Actuator

    E-print Network

    Stefanopoulou, Anna

    is the electromechanical valve actuator, recently receiving attention for enabling variable valve timing in internal (EVA) for use in achieving variable valve timing (VVT) in automotive engines. By de-coupling the valveExtremum Seeking Control for Soft Landing of an Electromechanical Valve Actuator Katherine S

  6. Integrated control and power electronics for an electro-mechanical valve actuation system

    Microsoft Academic Search

    Lawrence A. Mianzo; Stephen J. Newton; Zeljko Popovic

    2005-01-01

    In an electro-mechanical valve actuated engine, computer-controlled solenoid actuators drive the valves that control airflow into the cylinders, allowing elimination of the camshaft and enabling fully variable valve timing. Control of individual valve timing optimized over all engine operating conditions allows the benefits of variable valve timing to be realized. This paper presents a power electronics and control electronics architecture

  7. How musical training affects cognitive development: rhythm, reward and other modulating variables

    PubMed Central

    Miendlarzewska, Ewa A.; Trost, Wiebke J.

    2014-01-01

    Musical training has recently gained additional interest in education as increasing neuroscientific research demonstrates its positive effects on brain development. Neuroimaging revealed plastic changes in the brains of adult musicians but it is still unclear to what extent they are the product of intensive music training rather than of other factors, such as preexisting biological markers of musicality. In this review, we synthesize a large body of studies demonstrating that benefits of musical training extend beyond the skills it directly aims to train and last well into adulthood. For example, children who undergo musical training have better verbal memory, second language pronunciation accuracy, reading ability and executive functions. Learning to play an instrument as a child may even predict academic performance and IQ in young adulthood. The degree of observed structural and functional adaptation in the brain correlates with intensity and duration of practice. Importantly, the effects on cognitive development depend on the timing of musical initiation due to sensitive periods during development, as well as on several other modulating variables. Notably, we point to motivation, reward and social context of musical education, which are important yet neglected factors affecting the long-term benefits of musical training. Further, we introduce the notion of rhythmic entrainment and suggest that it may represent a mechanism supporting learning and development of executive functions. It also hones temporal processing and orienting of attention in time that may underlie enhancements observed in reading and verbal memory. We conclude that musical training uniquely engenders near and far transfer effects, preparing a foundation for a range of skills, and thus fostering cognitive development. PMID:24672420

  8. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring.

    PubMed

    Plews, Daniel J; Laursen, Paul B; Stanley, Jamie; Kilding, Andrew E; Buchheit, Martin

    2013-09-01

    The measurement of heart rate variability (HRV) is often considered a convenient non-invasive assessment tool for monitoring individual adaptation to training. Decreases and increases in vagal-derived indices of HRV have been suggested to indicate negative and positive adaptations, respectively, to endurance training regimens. However, much of the research in this area has involved recreational and well-trained athletes, with the small number of studies conducted in elite athletes revealing equivocal outcomes. For example, in elite athletes, studies have revealed both increases and decreases in HRV to be associated with negative adaptation. Additionally, signs of positive adaptation, such as increases in cardiorespiratory fitness, have been observed with atypical concomitant decreases in HRV. As such, practical ways by which HRV can be used to monitor training status in elites are yet to be established. This article addresses the current literature that has assessed changes in HRV in response to training loads and the likely positive and negative adaptations shown. We reveal limitations with respect to how the measurement of HRV has been interpreted to assess positive and negative adaptation to endurance training regimens and subsequent physical performance. We offer solutions to some of the methodological issues associated with using HRV as a day-to-day monitoring tool. These include the use of appropriate averaging techniques, and the use of specific HRV indices to overcome the issue of HRV saturation in elite athletes (i.e., reductions in HRV despite decreases in resting heart rate). Finally, we provide examples in Olympic and World Champion athletes showing how these indices can be practically applied to assess training status and readiness to perform in the period leading up to a pinnacle event. The paper reveals how longitudinal HRV monitoring in elites is required to understand their unique individual HRV fingerprint. For the first time, we demonstrate how increases and decreases in HRV relate to changes in fitness and freshness, respectively, in elite athletes. PMID:23852425

  9. Safety Valves

    Microsoft Academic Search

    V. M. Krasil'shchikov

    2001-01-01

    This problem can be solved in several different ways. In some cases, by means of a spring of specified strength that interacts with a drive mechanism (controlled by the pressure in the outlet cavity of the valve body) and the medium in contact with the working member (interacting with the valve seat) [1] and in other cases, by means of

  10. Improved Merge Valve

    NASA Technical Reports Server (NTRS)

    George-Falvy, Dez

    1992-01-01

    Circumferential design combines compactness and efficiency. In remotely controlled valve, flow in tributary duct along circumference of primary duct merged with flow in primary duct. Flow in tributary duct regulated by variable throat nuzzle driven by worm gear. Design leak-proof, and most components easily fabricated on lathe.

  11. Self-regulating valve

    Microsoft Academic Search

    Humphreys

    1982-01-01

    A variable, self-regulating valve having a hydraulic loss coefficient proportional to a positive exponential power of the flow rate. The device includes two objects in a flow channel and structure which assures that the distance between the two objects is an increasing function of the flow rate. The range of spacing between the objects is such that the hydraulic resistance

  12. Anomalous temperature dependence of training effect in specular spin valve using ultrathin Cr2O3-nano-oxide layer with magnetoelectric effect

    NASA Astrophysics Data System (ADS)

    Sawada, Kazuya; Shimomura, Naoki; Doi, Masaaki; Sahashi, Masashi

    2010-05-01

    Exchange bias from antiferromagnetic (AFM) oxides with a magnetoelectric (ME) effect has been studied for controlling ferromagnetic (FM) magnetizations by an applying electric field. However, thick ME oxides are needed for realizing the electrically controlled exchange biasing. Therefore, in this study the temperature dependencies of the training effect for the Cr2O3-nano-oxide-layer (NOL) are investigated for confirming the ME effect of the Cr2O3-NOL. The anomalous temperature tendencies of system dependent constant for exchange bias and magnetoresistance (MR), ?Hex and ?MR, were observed, which are probably originated from the ME effect of the Cr2O3-NOL because (1) these anomalous temperature tendencies could not be obtained in the CoO-NOL spin valve and (2) the ?Hex and ?MR are defined as the strength of the coupling between FM and AFM spins. It is remarkable result for us to confirm the possibility of the ME effect from the ultrathin Cr2O3 layer (less than 1 nm) because the ME effect was observed in only thick ME materials.

  13. Depressurization valve

    DOEpatents

    Skoda, George I. (Santa Clara, CA)

    1989-01-01

    A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring--preferably of the Belleville variety--acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion. The latch plate in surrounding the stem is limited in its outward movement by a boss attached to the stem at the end of the stem remote from the disk. The latch plate is held normally closed by three radial latches spaced at 120.degree. around the periphery of the plate.

  14. Self-regulating valve

    DOEpatents

    Humphreys, D.A.

    1982-07-20

    A variable, self-regulating valve having a hydraulic loss coefficient proportional to a positive exponential power of the flow rate. The device includes two objects in a flow channel and structure which assures that the distance between the two objects is an increasing function of the flow rate. The range of spacing between the objects is such that the hydraulic resistance of the valve is an increasing function of the distance between the two objects so that the desired hydraulic loss coefficient as a function of flow rate is obtained without variation in the flow area.

  15. Nuclear radiation actuated valve

    DOEpatents

    Christiansen, David W. (Kennewick, WA); Schively, Dixon P. (Richland, WA)

    1985-01-01

    A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

  16. Atrioventricular Valves

    NSDL National Science Digital Library

    PhD Jack D Thatcher (West Virginia School of Osteopathic Medicine Structural Biology)

    2009-11-20

    This FlashTM animation depicts development of the atrioventricular canal into the bicuspid and tricuspid valves. For context it begins with a ventral view of the two chambered heart. Clicking causes the surface to open revealing a cross section through the primitive ventricle. Next the animation zooms in to show the atrioventricular canal developing endocardial cushions and separating into the right and left atrioventricular orifices. From there the perspective shifts to show a cross section through the left orifice and depicts a stylized view of the development of an AV valve. The animation then shifts back to show a ventral view of the bicuspid and tricuspid valves, and ends with corpuscles pouring through the valves as they open and close.

  17. Training

    Cancer.gov

    CCT provides funding to support training and career development for cancer researchers working at institutions nationwide and also manages intramural training programs offered at NCI laboratories and offices.

  18. Design of a gas force simulator for the MIT Electromechanical Valve Drive project

    E-print Network

    Otten, James S. (James Stewart)

    2006-01-01

    The MIT electromechanical Valve Drive (EMVD) is a continuously variable valve actuation device for an automotive internal combustion engine. Current experimentation of the EMVD has been limited to intake valve events. When ...

  19. Simulation of a novel electromechanical engine valve drive to quantify performance gains in fuel consumption

    E-print Network

    Miller, Justin (Justin Lee)

    2011-01-01

    This thesis describes the modeling and simulation of a novel electromechanical valve drive known as the MIT EMV. This valve drive allows an engine to achieve variable valve timing which has been shown to produce improvements ...

  20. PERFORMANCE OF AN AERIAL VARIABLE-RATE APPLICATION SYSTEM WITH A HYDRAULICALLY POWERED CHEMICAL PUMP AND SPRAY VALVE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The performance was evaluated for a variable-rate system that consisted of a SATLOC M3 with AirTrac software with WAAS corrected DGPS (5 Hz position update) and an AutoCal II automatic flow controller. This system was installed on an Air Tractor 402B equipped with an auxiliary hydraulic package tha...

  1. Mitral valve prolapse

    MedlinePLUS

    Mitral valve prolapse is a heart problem involving the mitral valve, which separates the upper and lower chambers of ... from moving backwards when the heart beats (contracts). Mitral valve prolapse is the term used when the valve does ...

  2. Nonlinear Control for Magnetic Levitation of Automotive Engine Valves

    E-print Network

    Grizzle, Jessy W.

    , and emissions [7]. In addition to providing variable valve timing (VVT), the EVA is capable of achieving variable valve lift (VVL) through magnetic levitation. With the exception of our previous work [111 Nonlinear Control for Magnetic Levitation of Automotive Engine Valves Katherine Peterson, Member

  3. Titanium in Engine Valve Systems

    NASA Astrophysics Data System (ADS)

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

    1987-03-01

    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.

  4. Design and Experimental Implementation of an Electromagnetic Engine Valve Drive

    E-print Network

    Parlikar, T.A.

    In conventional internal combustion engines, engine valve displacements are fixed relative to crankshaft position. If these valves were actuated as a variable function of crankshaft angle, significant improvements in fuel ...

  5. Piezoelectric valve

    DOEpatents

    Petrenko, Serhiy Fedorovich

    2013-01-15

    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.

  6. Aortic Valve

    MedlinePLUS

    ... way the extra work may cause symptoms of heart failure, such as shortness of breath. Early on the shortness of breath may be noticeable only with exercise. Later, with the progression of valve disease, a patient could experience shortness of breath with even light ...

  7. Plasma valve

    DOEpatents

    Hershcovitch, Ady (Mount Sinai, NY); Sharma, Sushil (Hinsdale, IL); Noonan, John (Naperville, IL); Rotela, Elbio (Clarendon Hills, IL); Khounsary, Ali (Hinsdale, IL)

    2003-01-01

    A plasma valve includes a confinement channel and primary anode and cathode disposed therein. An ignition cathode is disposed adjacent the primary cathode. Power supplies are joined to the cathodes and anode for rapidly igniting and maintaining a plasma in the channel for preventing leakage of atmospheric pressure through the channel.

  8. training

    Microsoft Academic Search

    LAWRENCE L. SPRIET; MARTIN J. GIBALA

    This article highlights new nutritional concerns or practices that may influence the adaptation to training. The discussion is based on the assumption that the adaptation to repeated bouts of training occurs during recovery periods and that if one can train harder, the adaptation will be greater. The goal is to maximize with nutrition the recovery\\/adaptation that occurs in all rest

  9. Miniature piezo electric vacuum inlet valve

    DOEpatents

    Keville, R.F.; Dietrich, D.D.

    1998-03-24

    A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability is disclosed. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional 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. 6 figs.

  10. Miniature piezo electric vacuum inlet valve

    DOEpatents

    Keville, Robert F. (Valley Springs, CA); Dietrich, Daniel D. (Livermore, CA)

    1998-03-24

    A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional 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.

  11. Heart rate variability in the assessment and biofeedback training of common mental health problems in children.

    PubMed

    Nada, Pop-Jordanova

    2009-01-01

    Heart rate variability (HRV) is a measure of the beat-to-beat variations in heart rate related to the work of autonomic nervous system. It may serve as a psychophysiological indicator for arousal, emotional state and stress level. We used this parameter in both the assessment and biofeedback training, for dealing with five groups of common mental health problem in school children (anxious-phobic, somatoform, obsessive-compulsive, attention deficit hyperactivity and conduct disorders). The obtained results were compared with healthy children at the same age. In order to define the four main characteristics of personality (extroversion/introversion, neuroticism/stability, psychopathological traits and honesty) Eysenck Personality Questionnaire was applied. Results showed significantly higher psychopathological traits in ADHD and somatoform group, lower extroversion in somatoform, higher neurotism in OCD and lower lie scores in ADHD and OCD groups. As HRV instrument we used Heart Math Freeze-Framer System. After 15 sessions of training, children from nearby all groups showed improved high and medium HRV which corresponded to the improved clinical outcome. Hereby, the best results were obtained for conduct and anxiety disorder, and the worst for ADHD. PMID:20380120

  12. Orthostatic influence on heart rate and blood pressure variability in trained persons with tetraplegia.

    PubMed

    Otsuka, Yasuko; Shima, Norihiro; Moritani, Toshio; Okuda, Kuniharu; Yabe, Kyonosuke

    2008-09-01

    To examine the orthostatic influence on heart rate and blood pressure variability in persons with tetraplegia playing wheelchair basketball, ten trained persons with tetraplegia, ten untrained persons with tetraplegia, and ten able-bodied participated in this study. Spectrum analysis of the ECG R-R interval and blood-pressure on a beat-by-beat basis during head-up tilt 60 degrees sitting were performed. The ratio of the high frequency to total frequency (HF/TF) in the R-R interval decreased from supine (0.5 +/- 0.2) to sitting (0.3 +/- 0.2), and the low frequency (LF) power in systolic blood pressure increased from 4.7 +/- 9.1 to 15.0 +/- 13.1 mmHg(2) only in the untrained persons with tetraplegia (P < 0.01). The decrease in the HF/TF ratio in the untrained persons with tetraplegia indicates attenuated parasympathetic activity to the orthostatic challenge and the similar increase in LF power indicate that parasympathetic activity was reduced and sympathetic activity increased only in these persons. These results suggest that training enhances cardiovascular stability in tetraplegic subjects. PMID:18542988

  13. Modular, self-contained hydraulic valve timing systems for internal combustion engines

    Microsoft Academic Search

    Wakeman

    1989-01-01

    A modular self-contained hydraulic variable valve timing system for use with an internal combustion engine of the type having an engine block which includes a rotatable cam shaft, and sets of intake and exhaust valves respectively operatively associated with combustion cylinders of the engine. The modular self-contained variable valve timing system comprising: a valve cover adapted to being coupled to

  14. Control of Charge Dilution in Turbocharged Diesel Engines via Exhaust Valve Timing

    E-print Network

    Stefanopoulou, Anna

    employ a Variable Valve Timing methodology that in steady-state achieves large levels of internal Exhaust the exhaust manifold to the intake manifold through an eEGR valve [8]. By employing Variable Valve Timing (VVTControl of Charge Dilution in Turbocharged Diesel Engines via Exhaust Valve Timing Hakan Yilmaz

  15. Fluid valve with wide temperature range

    NASA Technical Reports Server (NTRS)

    Kast, Howard Berdolt (Inventor)

    1976-01-01

    A fluid valve suitable for either metering or pressure regulating fluids at various temperatures is provided for a fuel system as may be utilized in an aircraft gas turbine engine. The valve includes a ceramic or carbon pad which cooperates with a window in a valve plate to provide a variable area orifice which remains operational during large and sometimes rapid variations in temperature incurred from the use of different fuels.

  16. Variability of serum markers of erythropoiesis during 6 days of racing in highly trained cyclists.

    PubMed

    Voss, S C; Alsayrafi, M; Bourdon, P C; Klodt, F; Nonis, D; Hopkins, W G; Schumacher, Y O

    2014-02-01

    The athlete biological passport for the fight against doping is currently based on longitudinal monitoring for abnormal changes in cellular blood parameters. Serum parameters related to altered erythropoiesis could be considered for inclusion in the passport. The aim of this study was to quantify the changes in such parameters in athletes during a period of intense exercise.12 highly trained cyclists tapered for 3 days before 6 days of simulated intense stage racing. Morning and afternoon blood samples were taken on most days and analysed for total protein, albumin, soluble transferrin receptor and ferritin concentrations. Plasma volume was determined via total haemoglobin mass measured by carbon-monoxide rebreathing. Percent changes in means from baseline and percent standard errors of measurement (analytical error plus intra-athlete variation) on each measurement occasion were estimated with mixed linear modelling of log-transformed measures. Means of all variables changed substantially in the days following the onset of racing, ranging from -13% (haemoglobin concentration) to +27% (ferritin). After the second day, errors of measurement were generally twice those at baseline. Plasma variables were affected by heavy exercise, either because of changes in plasma volume (total protein, albumin, haemoglobin), acute phase/inflammatory reactions (ferritin) or both (soluble transferrin receptor). These effects need to be taken into consideration when integrating a plasma parameter into the biological passport model for athletes. PMID:23868682

  17. Fluid actuated pipeline valve

    SciTech Connect

    Pringle, R.E.

    1986-03-25

    A pipeline valve is described consisting of: a vertically positioned body, a valve seat positioned coaxially in the body in a horizontal plane, a valve element positioned upstream of the seat and axially movable in the body for movement towards and away from the valve seat whereby the weight of the valve element acts to move the valve element towards the seat, the cross-sectional area of the valve element being substantially less than the cross-sectional area of the body thereby reducing the restriction of flow through the body by the valve element when the valve is opened, first and second hydraulic piston and cylinder assemblies positioned in the body and connected between the valve element and the valve body for moving the valve element away from the valve seat, the first and second assemblies being diametrically opposed to each other and parallel to the longitudinal axis of the body, sealing valve and seat means positioned upstream of the valve seat about each piston and cylinder assembly and adapted to close and seal off the assemblies when the valve is closed, the piston and cylinder assemblies being in communication with the exterior of the body at a location downstream of the valve seat for repairing the assemblies when the valve is closed, and guide means between the valve element and the body for axially guiding the valve element in the body.

  18. Well treatment valve

    SciTech Connect

    Elphick, J.

    1984-05-29

    A well treatment valve includes spring means within a spring chamber acting against an actuating rod movable against a valve body to open and close the valve. The spring means is sealed against pressure in an inlet to the valve while a passage communicates between the valve inlet and the spring chamber. The spring means is a gas spring.

  19. Dual flapper valve assembly

    Microsoft Academic Search

    S. R. Clary; F. Jr. Giusti; R. M. Sproul

    1989-01-01

    This patent describes a dual flapper valve assembly for limiting the loss of completion fluid in connection with a well service operation. The valve assembly consists of: tubular support means defining a flow passage; a first flapper valve assembly connected in series flow relation with the support means, the first flapper valve assembly having a valve closure member movable between

  20. Rubber valve seal with tough skin

    NASA Technical Reports Server (NTRS)

    Martin, J. W.

    1979-01-01

    Curing technique for producing variable viscosity seal has hard sealing surface supported by softer rubber. Valve seal is clamped between two jaws for curing with hotter jaw at temperature of approximately 350 F and lower at room temperature. Result is durable tight valve-seat.

  1. Effects of Exercise Training on Heart Rate Variability in Chagas Heart Disease

    PubMed Central

    Nascimento, Bruno Ramos; Lima, Márcia Maria Oliveira; Nunes, Maria do Carmo Pereira; de Alencar, Maria Clara Noman; Costa, Henrique Silveira; Pinto Filho, Marcelo Martins; Cota, Vitor Emanuel Serafim; Rocha, Manoel Otávio da Costa; Ribeiro, Antonio Luiz Pinho

    2014-01-01

    Background: Heart rate variability (HRV) is a marker of autonomic dysfunction severity. The effects of physical training on HRV indexes in Chagas heart disease (CHD) are not well established. Objective: To evaluate the changes in HRV indexes in response to physical training in CHD. Methods: Patients with CHD and left ventricular (LV) dysfunction, physically inactive, were randomized either to the intervention (IG, N = 18) or control group (CG, N = 19). The IG participated in a 12-week exercise program consisting of 3 sessions/week. Results: Mean age was 49.5 ± 8 years, 59% males, mean LVEF was 36.3 ± 7.8%. Baseline HRV indexes were similar between groups. From baseline to follow-up, total power (TP): 1653 (IQ 625 - 3418) to 2794 (1617 - 4452) ms, p = 0.02) and very low frequency power: 586 (290 - 1565) to 815 (610 - 1425) ms, p = 0.047) increased in the IG, but not in the CG. The delta (post - pre) HRV indexes were similar: SDNN 11.5 ± 30.0 vs. 3.7 ± 25.1 ms. p = 0.10; rMSSD 2 (6 - 17) vs. 1 (21 - 9) ms. p = 0.43; TP 943 (731 - 3130) vs. 1780 (921 - 2743) Hz. p = 0.46; low frequency power (LFP) 1.0 (150 - 197) vs. 60 (111 - 146) Hz. p = 0.85; except for high frequency power, which tended to increase in the IG: 42 (133 - 92) vs. 79 (61 - 328) Hz. p = 0.08). Conclusion: In the studied population, the variation of HRV indexes was similar between the active and inactive groups. Clinical improvement with physical activity seems to be independent from autonomic dysfunction markers in CHD. PMID:25098373

  2. Year-to-year variability in haemoglobin mass response to two altitude training camps

    PubMed Central

    McLean, Blake D; Buttifant, David; Gore, Christopher J; White, Kevin; Kemp, Justin

    2013-01-01

    Aim To quantify the year-to-year variability of altitude-induced changes in haemoglobin mass (Hbmass) in elite team-sport athletes. Methods 12 Australian-Footballers completed a 19-day (ALT1) and 18-day (ALT2) moderate altitude (?2100?m), training camp separated by 12?months. An additional 20 participants completed only one of the two training camps (ALT1 additional n=9, ALT2 additional n=11). Total Hbmass was assessed using carbon monoxide rebreathing before (PRE), after (POST1) and 4?weeks after each camp. The typical error of Hbmass for the pooled data of all 32 participants was 2.6%. A contemporary statistics analysis was used with the smallest worthwhile change set to 2% for Hbmass. Results POST1 Hbmass was very likely increased in ALT1 (3.6±1.6%, n=19; mean±?90 CL) as well as ALT2 (4.4±1.3%, n=23) with an individual responsiveness of 1.3% and 2.2%, respectively. There was a small correlation between ALT1 and ALT2 (R=0.21, p=0.59) for a change in Hbmass, but a moderately inverse relationship between the change in Hbmass and initial relative Hbmass (g/kg (R=?0.51, p=0.04)). Conclusions Two preseason moderate altitude camps 1?year apart yielded a similar (4%) mean increase in Hbmass of elite footballers, with an individual responsiveness of approximately half the group mean effect, indicating that most players gained benefit. Nevertheless, the same individuals generally did not change their Hbmass consistently from year to year. Thus, a ‘responder’ or ‘non-responder’ to altitude for Hbmass does not appear to be a fixed trait. PMID:24282208

  3. High speed exhaust gas recirculation valve

    DOEpatents

    Fensom, Rod (Peterborough, GB); Kidder, David J. (Peterborough, GB)

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  4. Application of alpha/theta neurofeedback and heart rate variability training to young contemporary dancers: state anxiety and creativity.

    PubMed

    Gruzelier, J H; Thompson, T; Redding, E; Brandt, R; Steffert, T

    2014-07-01

    As one in a series on the impact of EEG-neurofeedback in the performing arts, we set out to replicate a previous dance study in which alpha/theta (A/T) neurofeedback and heart rate variability (HRV) biofeedback enhanced performance in competitive ballroom dancers compared with controls. First year contemporary dance conservatoire students were randomised to the same two psychophysiological interventions or a choreology instruction comparison group or a no-training control group. While there was demonstrable neurofeedback learning, there was no impact of the three interventions on dance performance as assessed by four experts. However, HRV training reduced anxiety and the reduction correlated with improved technique and artistry in performance; the anxiety scale items focussed on autonomic functions, especially cardiovascular activity. In line with the putative impact of hypnogogic training on creativity A/T training increased cognitive creativity with the test of unusual uses, but not insight problems. Methodological and theoretical implications are considered. PMID:23684733

  5. Conical Seat Shut-Off Valve

    NASA Technical Reports Server (NTRS)

    Farner, Bruce

    2013-01-01

    A moveable valve for controlling flow of a pressurized working fluid was designed. This valve consists of a hollow, moveable floating piston pressed against a stationary solid seat, and can use the working fluid to seal the valve. This open/closed, novel valve is able to use metal-to-metal seats, without requiring seat sliding action; therefore there are no associated damaging effects. During use, existing standard high-pressure ball valve seats tend to become damaged during rotation of the ball. Additionally, forces acting on the ball and stem create large amounts of friction. The combination of these effects can lead to system failure. In an attempt to reduce damaging effects and seat failures, soft seats in the ball valve have been eliminated; however, the sliding action of the ball across the highly loaded seat still tends to scratch the seat, causing failure. Also, in order to operate, ball valves require the use of large actuators. Positioning the metal-to-metal seats requires more loading, which tends to increase the size of the required actuator, and can also lead to other failures in other areas such as the stem and bearing mechanisms, thus increasing cost and maintenance. This novel non-sliding seat surface valve allows metal-to-metal seats without the damaging effects that can lead to failure, and enables large seating forces without damaging the valve. Additionally, this valve design, even when used with large, high-pressure applications, does not require large conventional valve actuators and the valve stem itself is eliminated. Actuation is achieved with the use of a small, simple solenoid valve. This design also eliminates the need for many seals used with existing ball valve and globe valve designs, which commonly cause failure, too. This, coupled with the elimination of the valve stem and conventional valve actuator, improves valve reliability and seat life. Other mechanical liftoff seats have been designed; however, they have only resulted in increased cost, and incurred other reliability issues. With this novel design, the seat is lifted by simply removing the working fluid pressure that presses it against the seat and no external force is required. By eliminating variables associated with existing ball and globe configurations that can have damaging effects upon a valve, this novel design reduces downtime in rocket engine test schedules and maintenance costs.

  6. Isolation valve selections play important role in pipelining

    Microsoft Academic Search

    R. Hingoraney; D. N. Goto

    1995-01-01

    Isolation valves are an integral part of every pipeline and play an important role in safe and proper operation. For almost every project, pipeline designers wrestle with choosing between the through-conduit gate valves and ball valves and their associated actuating mechanisms. Complicating this selection process are variables such as individual preferences and the lack of broad-based operating experience. As expected,

  7. Earthquake relief valve

    SciTech Connect

    Diamond, H.E.

    1989-04-18

    A shock actuated shut-off valve is described, comprising: a valve, having an open position and a closed position, rotatably mounted within a valve body; a valve stem connected to the valve; an elongated handle having a valve stem engagement end and a ball detent engagement end, the valve stem engagement end connected to the valve stem; means for urging the valve to rotate into the closed position; means for stopping further rotation of the valve when the valve is in the closed position; a ball detent; and a pendulum having a ball detent engagement end and a plumb end, the ball detent engagement end supporting the second ball, the pendulum responding to a shock by freeing the second ball, thereby freeing the elongate handle and allowing the valve to move to the closed position.

  8. Heart valve surgery

    MedlinePLUS

    ... will remove your valve and put a new one in place. The main types of new valves are: Mechanical -- made of man-made materials, such as metal (stainless steel or titanium) or ceramic. These valves last the longest, but ...

  9. Mitral valve surgery - open

    MedlinePLUS

    ... remove your mitral valve and sew a new one into place. There are two types of mitral valves: Mechanical -- made of man-made (synthetic) materials, such as titanium. These valves last the longest. You will need ...

  10. Aortic valve surgery - open

    MedlinePLUS

    ... remove your aortic valve and sew a new one into place. There are two main types of new valves: Mechanical -- made of man-made materials, such as titanium or carbon. These valves last the longest. You ...

  11. Aerobic group training improves exercise capacity and heart rate variability in elderly patients with a recent coronary event A randomized controlled study

    Microsoft Academic Search

    A. Stahle; R. Nordlander; L. Bergfeldt

    Aims Reduced heart rate variability is associated with an unfavourable prognosis in patients with ischaemic heart disease. Whether physical training can modify this risk factor is not definitely proven. Our hypothesis was that training might increase both physical capacity and heart rate variability in elderly patients recovering from an acute coronary event, i.e. acute myocardial infarction (n=38) or an episode

  12. EXPERIMENTAL CONTROL OF VARIABLE CAM TIMING ACTUATORS

    E-print Network

    Piston Spool valve Figure 1. Variable Valve Timing actuator scheme.EXPERIMENTAL CONTROL OF VARIABLE CAM TIMING ACTUATORS Jonathan Chauvin Nicolas Petit Institut Abstract: In this paper, we propose a control scheme for the position of Variable Cam Timing (VCT

  13. Adaptive Training of Manual Control: 1. Comparison of Three Adaptive Variables and Two Logic Schemes.

    ERIC Educational Resources Information Center

    Norman, D. A.; And Others

    "Machine controlled adaptive training is a promising concept. In adaptive training the task presented to the trainee varies as a function of how well he performs. In machine controlled training, adaptive logic performs a function analogous to that performed by a skilled operator." This study looks at the ways in which gain-effective time constant…

  14. Detraining Produces Minimal Changes in Physical Performance and Hormonal Variables in Recreationally Strength-Trained Men

    Microsoft Academic Search

    WILLIAM J. KRAEMER; L. PERRY KOZIRIS; NICHOLAS A. RATAMESS; KEIJO HÄKKINEN; N. TRAVIS TRIPLETT-McBRIDE; ANDREW C. FRY; SCOTT E. GORDON; JEFF S. VOLEK; DUNCAN N. FRENCH; MARTYN R. RUBIN; ANA L. GÓMEZ; MATTHEW J. SHARMAN; J. MICHAEL LYNCH; MIKEL IZQUIERDO; ROBERT U. NEWTON; STEVEN J. FLECK

    2002-01-01

    The object of this study was to examine changes in muscular strength, power, and resting hormonal concentrations during 6 weeks of detraining (DTR) in recreationally strength- trained men. Each subject was randomly assigned to either a DTR (n 5 9) or resistance training (RT; n 5 7) group after being matched for strength, body size, and training experi- ence. Muscular

  15. Improvement of Circadian Rhythm of Heart Rate Variability by Eurythmy Therapy Training

    PubMed Central

    Seifert, Georg; Kanitz, Jenny-Lena; Pretzer, Kim; Henze, Günter; Witt, Katharina; Reulecke, Sina; Voss, Andreas

    2013-01-01

    Background. Impairment of circadian rhythm is associated with various clinical problems. It not only has a negative impact on quality of life but can also be associated with a significantly poorer prognosis. Eurythmy therapy (EYT) is an anthroposophic movement therapy aimed at reducing fatigue symptoms and stress levels. Objective. This analysis of healthy subjects was conducted to examine whether the improvement in fatigue symptoms was accompanied by improvements in the circadian rhythm of heart rate variability (HRV). Design. Twenty-three women performed 10 hours of EYT over six weeks. Electrocardiograms (ECGs) were recorded before and after the EYT trial. HRV was quantified by parameters of the frequency and time domains and the nonlinear parameters of symbolic dynamics. Results. The day-night contrast with predominance of vagal activity at night becomes more pronounced after the EYT training, and with decreased Ultralow and very low frequencies, the HRV shows evidence of calmer sleep. During the night, the complexity of the HRV is significantly increased indicated by nonlinear parameters. Conclusion. The analysis of the circadian patterns of cardiophysiological parameters before and after EYT shows significant improvements in HRV in terms of greater day-night contrast caused by an increase of vagal activity and calmer and more complex HRV patterns during sleep. PMID:23533496

  16. Fast-Acting Valve

    NASA Technical Reports Server (NTRS)

    Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

    2003-01-01

    A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

  17. Pulmonary valve stenosis

    MedlinePLUS

    ... valve pulmonary stenosis; Pulmonary stenosis; Stenosis - pulmonary valve; Balloon valvuloplasty - pulmonary ... water pills) Treat abnormal heartbeats and rhythms Percutaneous balloon pulmonary dilation (valvuloplasty) may be performed when no ...

  18. Subsurface well safety valve

    SciTech Connect

    Carmody, M.A.; Lembcke, J.L.

    1989-01-10

    This patent describes a valve for controlling the flow in a fluid transmission conduit in a subteranean well comprising a tubular valve housing defining an axial fluid passage, a valve closure member shiftably mounted in the valve housing for movement between an open and closed position relative to the fluid passage, resilient means biasing the valve closure member to the closed position, a valve-actuator sleeve concentrically mounted within the tubular valve housing for axial movements between two positions relative to the valve closure member, in one of the positions holding the valve closure member in the open position and in the other of the two positions permitting the valve closure member to close and fluid pressure operated means for axially shifting the valve actuator sleeve to the one position.

  19. Low-noise nozzle valve

    NASA Technical Reports Server (NTRS)

    Gwin, Hal S. (inventor); Aaron, James (inventor)

    1990-01-01

    A low noise, variable discharage area, valve is constructed having opposed recesses within which a pair of gates are slidably disposed. Each of the gates is provided with upstream edges having a radius thereon, the radius enabling smooth, accelerated, low noise flow therebetween. The gates are further provided with tracks along each side, which in turn slide along splines set in the side walls of the valve. A threaded rod which rotates in a threaded insert in a rear wall of each of the gates, serves to move the gates within their respective recesses.

  20. Stage cementing valve

    SciTech Connect

    Lindsey, H.E.; Adams, R.W.

    1989-11-14

    This patent describes a method for stage cementing a string of pipe in a well bore. The string of pipe includes a stage valve having a tubular valve collar intermediate of its length and has a tubular sleeve valve member slidably received in the stage collar for movement between first and second longitudinal positions relative to the stage collar and where the sleeve valve member has a flange in engagement with an engagement surface on the valve collar in the first longitudinal position. The sleeve valve member has a piston portion located in an annular chamber between the sleeve valve member and the valve collar and where the sleeve valve member has a sleeve valve port with access to one surface of the piston portion in the annular chamber for placing the one surface in fluid communication with the bore of the sleeve valve member. The valve collar has a valve collar port with access to the other surface of the of the piston portion in the annular chamber for placing the other surface in fluid communication with the exterior of the valve collar. The piston portion separates the sleeve valve port from the valve collar in a the first longitudinal position and permits the ports to be in fluid communication with one another in an the second longitudinal position.

  1. Mitral Valve Prolapse

    MedlinePLUS

    ... of the mitral valve What causes mitral valve prolapse? Mitral valve prolapse (MVP) is among the most common heart conditions, ... nlm.nih.gov/medlineplus/mitralvalveprolapse.html Mitral Valve Prolapse PubMed Health www.ncbi.nlm.nih.gov/pubmedhealth/ ...

  2. A practical thermopneumatic valve

    Microsoft Academic Search

    Charles Grosjean; Xing Yang; Yu-Chong Tai

    1999-01-01

    Previously, we reported a thermopneumatic silicone rubber membrane valve [1997]. This valve combined thermopneumatic actuation with a low modulus silicone rubber membrane. However, the leakage of the working fluid through the membrane rendered the valve unusable in a day or two. Here, we present extensive optimization and characterization of a redesigned valve structure. This new design has a suspended membrane

  3. Artificial Heart Valve Design

    E-print Network

    Provancher, William

    of the heart being overworked can cause the beginning of heart failure (i.e. shortness of breath, fatigueArtificial Heart Valve Design Your Chance to be a Biomedical Engineer #12;Circulatory System Video #12;What is a Heart Valve? · Heart Valve Video #12;#12;What Does a Heart Valve Do? · Maintain the one

  4. Liquid rocket valve components

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A monograph on valves for use with liquid rocket propellant engines is presented. The configurations of the various types of valves are described and illustrated. Design criteria and recommended practices for the various valves are explained. Tables of data are included to show the chief features of valve components in use on operational vehicles.

  5. Vapor management valve

    Microsoft Academic Search

    D. L. DeLand; C. A. Detweiler; G. V. Beneker

    1994-01-01

    A flow regulator for automotive vehicles of the type having a computer-controlled emission control system. The flow regulator has an electric vacuum regulator (EVR) valve that regulates the vacuum signal provided to a vacuum regulator valve in accordance with the current signal supplied to the EVR valve by the engine controller unit. The vacuum regulator valve includes a control chamber

  6. Rotary pneumatic valve

    DOEpatents

    Hardee, Harry C. (Albuquerque, NM)

    1991-01-01

    A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.

  7. Changes in inflammatory activity, heart rate variability, and biochemical indices in young athletes during the annual training cycle

    Microsoft Academic Search

    A. A. Kylosov; A. A. Mel’nikov; A. Yu. Mal’tsev; A. D. Vikulov; O. L. Borisova

    2009-01-01

    Inflammatory activity, heart rate variability (HRV), and biochemical and functional indices were assessed in young ski racers\\u000a during the preparation, competition, and recovery periods of an annual training cycle. During the preparation period, autohemodilution\\u000a (decreased red blood cell count (RBC) and hematocrit (Ht) levels) and a decrease in the systemic inflammatory activity (C-reactive\\u000a protein) occurred, without significant differences in the

  8. Dual stage check valve

    NASA Technical Reports Server (NTRS)

    Whitten, D. E. (inventors)

    1973-01-01

    A dual stage seat valve head arrangement is described which consists of a primary sealing point located between a fixed orifice seat and a valve poppet, and a secondary sealing point between an orifice poppet and a valve poppet. Upstream of the valve orifice is a flexible, convoluted metal diaphragm attached to the orifice poppet. Downstream of the valve orifice, a finger spring exerts a force against the valve poppet, tending to keep the valve in a closed position. The series arrangement of a double seat and poppet is able to tolerate small particle contamination while minimizing chatter by controlling throttling or metering across the secondary seat, thus preserving the primary sealing surface.

  9. Fluid valve assembly

    NASA Technical Reports Server (NTRS)

    Huber, W. C. (inventor)

    1978-01-01

    A valve assembly is reported for controlling the flow of fluids between the inlet and outlet of a fluid valve. The valve assembly contains a barrier element which is porous for providing fluid communication between the valve inlet and outlet. The valve assembly also includes a sealing element that is movable relative to the barrier element between a first position, in which fluid flow through the porous portion of the barrier element is blocked preventing fluid communication between the valve inlet and outlet, and a second position, in which the porous portion is unblocked, permitting fluid communication between the valve inlet and outlet.

  10. Bellows sealed plug valve

    DOEpatents

    Dukas, Jr., Stephen J. (Idaho Falls, ID)

    1990-01-01

    A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion.

  11. Throttle valve controlling apparatus

    SciTech Connect

    Ejiri, Y.; Kamifuji, H.

    1986-07-22

    An apparatus is described for controlling an open degree of a throttle valve fixed to a throttle valve shaft for swing movement around an axis of the throttle valve shaft so as to control an air-fuel mixture flow to be supplied to an engine. The apparatus consists of: a motor including a rotor portion which is associated with the throttle valve shaft to swing the throttle valve; means for detecting an amount of swing movement of the throttle valve and for producing a signal corresponding to the opening degree of the throttle valve; a control unit for receiving and judging the signal from the detecting means and for outputting a command to the motor so as to swing the throttle valve in a desired opening degree; a one piece throttle valve shaft on which the throttle valve and the rotor portion of the motor are separately disposed; and wherein the rotor portion and the one piece shaft are molded together.

  12. Vacuum breaker valve assembly

    DOEpatents

    Thompson, J.L.; Upton, H.A.

    1999-04-27

    Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening. 1 fig.

  13. Scissor thrust valve actuator

    DOEpatents

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

    2006-08-29

    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.

  14. Vacuum breaker valve assembly

    DOEpatents

    Thompson, Jeffrey L. (San Jose, CA); Upton, Hubert Allen (Morgan Hill, CA)

    1999-04-27

    Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening.

  15. Valve for fluid control

    DOEpatents

    Oborny, Michael C. (Albuquerque, NM); Paul, Phillip H. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Frye-Mason, Gregory C. (Cedar Crest, NM); Manginell, Ronald P. (Albuquerque, NM)

    2001-01-01

    A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.

  16. Transjugular approach in valve-in-valve transcatheter mitral valve replacement: direct route to the valve.

    PubMed

    Kaneko, Tsuyoshi; Swain, JaBaris D; Loberman, Dan; Welt, Frederick G P; Davidson, Michael J; Eisenhauer, Andrew C

    2014-06-01

    With the recent emergence of transcatheter valve replacement, high-risk cases of structural valve deterioration after mitral bioprosthesis can be treated with valve-in-valve transcatheter mitral valve replacement (TMVR). The transapical approach has become the principal access for TMVR, but we report an alternative direct access for TMVR--transjugular transseptal route--in an 81-year-old woman with a degenerated mitral bioprosthesis. PMID:24882333

  17. Valve for subterraneal wells

    SciTech Connect

    Akkerman, N. H.

    1984-10-09

    The invention relates to an improved subterranean well safety valve wherein an annular actuator is moved downwardly by applied fluid pressure to effect the opening movement of a valve head of a valve relative to an annular valve seat. The initial downward movement of the actuator effects the displacement of a valve stem which extends through a restricted aperture in the valve head, moving a ball valve segment on the valve stem from a seat in the aperture, thus permitting the bleeding of any fluid pressure differential existing on the lower side of the valve head relative to the upper side and reducing the amount of force required to move the valve to its open position. Additionally, in one embodiment, a locking sleeve is slidably mounted within the shiftable annular actuator and such sleeve is operable by an auxiliary tool to effect the radial shifting of locking elements carried by the actuator into locking engagement with the valve housing to achieve a temporary locking of the valve in an open position. The travel of the locking sleeve relative to the valve housing in a reverse direction is limited by a shearable pin so that reverse forcible movement of the locking sleeve will shear the pin and effect a permanent locking of the radially expansible locking segments carried by the actuating sleeve to the valve housing, thus permanently locking the valve in an open position.

  18. Continuous-camlobe phasing: An advanced valve-timing approach

    Microsoft Academic Search

    M. T. Nelson; A. C. Elrod

    1987-01-01

    Variable-valve timing allows for controlled scheduling of valve-timing events. When applied to spark-ignition engines, it yields improvements in emissions, economy, and performance. The benefits for diesel engines further include: improved starting, noise reduction, and the ability to vary compression ratios. A camlobe-phasing system which takes advantage of the merits of variable-valve timing has been developed. Some advantages of this advanced

  19. An Approach for Modeling the Effects of Gas Exchange Processes on HCCI Combustion and Its Application in Evaluating Variable Valve Timing Control Strategies

    Microsoft Academic Search

    Aristotelis Babajimopoulos; Dennis N. Assanis; Scott B. Fiveland

    The present study introduces a modeling approach for investigating the effects of valve events and gas exchange processes in the framework of a full-cycle HCCI engine simulation. A multi-dimensional fluid mechanics code, KIVA-3V, is used to simulate exhaust, intake and compression up to a transition point, before which chemical reactions become important. The results are then used to initialize the

  20. Modelling and multi-objective optimization of a variable valve-timing spark-ignition engine using polynomial neural networks and evolutionary algorithms

    Microsoft Academic Search

    K. Atashkari; N. Nariman-Zadeh; M. Gölcü; A. Khalkhali; A. Jamali

    2007-01-01

    The main reason for the efficiency decrease at part load conditions for four-stroke spark-ignition (SI) engines is the flow restriction at the cross-sectional area of the intake system. Traditionally, valve-timing has been designed to optimize operation at high engine-speed and wide open throttle conditions. Several investigations have demonstrated that improvements at part load conditions in engine performance can be accomplished

  1. Robotic mitral valve surgery.

    PubMed

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

    2003-12-01

    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 placement of an atrial retractor, as well as needle, tissue, and suture retrieval. With the development of specialized retractors and a delivery/retrieval port, a truly endoscopic approach will be consistently reproducible. New navigation systems and image guided surgery portend an improving future for robotic cardiac surgery. Recently, we have combined robotically guided microwave catheters for ablation of atrial fibrillation with robotic mitral valve repairs (Fig. 8). Thus, we are beginning to achieve the ideal operation, with a native valve repair and a return to normal sinus rhythm. Robotic cardiac surgery is an evolutionary process, and even the greatest skeptics must concede that progress has been made toward endoscopic cardiac valve operations. Surgical scientists must continue to critically evaluate this technology in this new era of cardiac surgery. Despite enthusiasm, caution cannot be overemphasized. Surgeons must be careful because indices of operative safety, speed of recovery, level of discomfort, procedural cost, and long-term operative quality have yet to be defined. Traditional valve operations still enjoy long-term success with ever-decreasing morbidity and mortality, and remain our measure for comparison. Surgeons must remember that we are seeking the most durable operation with the least human trauma and quickest return to normalcy, all done at the lowest cost with the least risks. Although we have moved more asymptotically to these goals, surgeons alone must map the path for the final ascent. PMID:14712874

  2. Spring and valve skirt

    SciTech Connect

    Moore, L.

    1986-07-29

    This patent describes an engine having a valve guide operatively mounting a valve stem and its associated valve spring and spring retainer for actuation of the valve stem by a valve actuator. An improvement is described comprising: a hollow, generally cylindrical shaped skirt means having a side portion forming an interior with one open end and having at its other end an end portion extending inwardly and formed with an axial opening therein communicating to the interior. The skirt means is mounted on and about the valve stem and spring retainer and about its spring so as to move with the valve stem and to cover the spring retainer and most of the portion of the valve spring and the valve stem extending outwardly from the valve guide except for an outermost end of the stem which extends through the opening in the end portion for actuation by the actuator , such that the inwardly extending end portion lies between the outermost end of the stem and an outermost end of the spring retainer to allow for retrofitting insertion of the skirt means over existing valve stems without removal of the spring and spring retainer. Excessive oil is presented from seeping between and valve guide and the valve stem thus preventing excessive carbon build-up in the combustion area, sticking valves, fouled plugs and high exhaust emissions.

  3. Oil drain valve

    SciTech Connect

    Laipply, R.A.; Fournier, P.J.E.

    1988-05-24

    An oil drain fitting for internal combustion engines is described comprising, in combination, an elongated tubular body having an inner end and an outer end, a passage axially extending through the body intersecting the ends, an external thread defined on the body adjacent the inner end for threading the body into an engine drain hole, valve operating attachment means defined on the body adjacent the outer end, a tubular valve axially reciprocally mounted within the passage having an open end adjacent the body outer end and a closed end adjacent the body inner end, a valve seat defined on the body adjacent the inner end, a valve head defined on the valve closed end engagable with the seat when the valve is axially positioned to a closed position, a port defined in the valve adjacent the head communicating with the interior of the valve whereby oil will flow into the valve when the valve is axially positioned to an open position when the head disengages the seat, spring means mounted on the body axially biasing the valve toward the closed position, and valve actuating means defined on the valve for axially displacing the valve from the closed position to the open position.

  4. Transcatheter aortic valve implantation

    PubMed Central

    Oliemy, Ahmed

    2014-01-01

    Transcatheter aortic valve implantation was developed to offer a therapeutic solution to patients with severe symptomatic aortic stenosis who are not candidates for conventional aortic valve replacement. The improvement in transcatheter aortic valve implantation outcomes is still of concern in the areas of stroke, vascular injury, heart block, paravalvular regurgitation and valve durability. Concomitantly, the progress, both technical and in terms of material advances of transcatheter valve systems, as well as in patient selection, renders transcatheter aortic valve implantation an increasingly viable treatment for more and more patients with structural heart disease. PMID:25374670

  5. Ball valve extractor

    DOEpatents

    Herndon, Charles (Walterboro, SC); Brown, Roger A. (North Augusta, SC)

    2002-01-01

    An apparatus and process for removing a ball valve is provided. The ball valve removal tool provides a handle sliding along the length of a shaft. One end of the shaft is secured within an interior cavity of a ball valve while the opposite end of the shaft defines a stop member. By providing a manual sliding force to the handle, the handle impacts the stop member and transmits the force to the ball valve. The direction of the force is along the shaft of the removal tool and disengages the ball valve from the ball valve housing.

  6. Quickly Removable Valve

    NASA Technical Reports Server (NTRS)

    Robbins, John S.

    1988-01-01

    Unit removed with minimal disturbance. Valve inlet and outlet ports adjacent to each other on same side of valve body. Ports inserted into special manifold on fluid line. Valve body attached to manifold by four bolts or, alternatively, by toggle clamps. Electromechanical actuator moves in direction parallel to fluid line to open and close valve. When necessary to clean valve, removed simply by opening bolts or toggle clamps. No need to move or separate ports of fluid line. Valve useful where disturbance of fluid line detrimental or where fast maintenance essential - in oil and chemical industries, automotive vehicles, aircraft, and powerplants.

  7. Transjugular tricuspid valve-in-valve implantation.

    PubMed

    Salizzoni, Stefano; La Torre, Michele; Barbero, Cristina; Marra, Walter Grosso; Moretti, Claudio; D'Amico, Maurizio; Rinaldi, Mauro

    2013-12-01

    A 60 year-old female underwent tricuspid valve replacement in 2002. Post-operative recovery was complicated by severe post-pericardiotomy-syndrome. Seven years later she underwent transcatheter valve-in-valve implantation through the right jugular vein because of early prosthesis deterioration. Moreover intra-operative transoesophageal echocardiography showed an important right-to-left shunt through the patent foramen ovale that immediately disappeared after the deployment of a 29-mm Sapien-XT. The patient had an immediate and dramatic improvement in day-by-day activities. This case shows that tricuspid valve deterioration can be safely and successfully treated through this approach. PMID:23726665

  8. Rendering the Electromechanical Valve Actuator Globally Asymptotically Stable Katherine S. Peterson*

    E-print Network

    Stefanopoulou, Anna

    of linearity. I. INTRODUCTION Variable valve timing (VVT) can significantly improve the performance of the internal combustion engine by de- coupling the engine valve timing from other engine events continuously variable lift, duration, and phasing of the valves. Unfortunately, the EVA suffers from large

  9. MOTION PLANNING CONTROL OF THE AIRPATH OF AN S.I. ENGINE WITH VALVE

    E-print Network

    with Variable Valve Timing actuators (VVT). Compared to standard configurations, the engine does not possess any losses, turbochargers are used. For such engines, Variable Valve Timing (VVT) devices are used to improveMOTION PLANNING CONTROL OF THE AIRPATH OF AN S.I. ENGINE WITH VALVE TIMING ACTUATORS T. Leroy , J

  10. Mitral valve prolapse.

    PubMed

    Schlant, R C; Felner, J M; Miklozek, C L; Lutz, J F; Hurst, J W

    1980-07-01

    Mitral valve prolapse (MVP) now is a commonly recognized syndrome with an apparent prevalence of approximately 4-6%. It appears to occur more frequently in females and occasionally it is familial. In most instances, the syndrome is idiopathic, although it occurs in association with many other conditions, particularly Marfan's syndrome, rheumatic heart disease, coronary heart disease, congestive cardiomyopathy, ostium secundum atrial septal defect, Ehlers-Danlos syndrome or abnormalities of the thoracic cage. The majority of patients with the syndrome have minimal, if any, symptoms and have a benign course. When symptoms do occur, more frequently they are palpitations, chest pain, dyspnea on exertion or fatigue. Neuropsychiatric symptoms or even transient ischemic episodes may occur rarely. Very rarely, complications such as severe mitral regurgitation, arrhythmias or infective endocarditis may occur. Characteristically, patients have a midsystolic click, occasionally followed by a systolic murmur. The timing of the click and the onset of the murmur usually is variable, depending on the ventricular volume. The electrocardiogram frequently shows ST-T wave changes. The diagnosis usually can be confirmed by echocardiography or left ventricular angiography. Most patients with MVP require no treatment other than reassurance. If a systolic murmur is present, prophylaxis against infective endocarditis during dental work probably is useful. Patients with palpitations or chest pain usually respond well to treatment with propranolol. Patients with progressive severe mitral regurgitation require mitral valve replacement. PMID:6993166

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

    NASA Astrophysics Data System (ADS)

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

    2008-10-01

    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.

  12. Acute effect of nitric oxide supplement on blood nitrate/nitrite and hemodynamic variables in resistance trained men.

    PubMed

    Bloomer, Richard J; Williams, Sara A; Canale, Robert E; Farney, Tyler M; Kabir, Mohammad M

    2010-10-01

    Nitric oxide dietary supplements are extremely popular within the sport and bodybuilding community. Most products contain l-arginine, for which there is no direct evidence that oral L-arginine increases circulating nitric oxide or blood flow. A new molecule (2-[nitrooxy]thyl 2-amino-3-methylbutanoate) is being marketed as a sport supplement for purposes of delivering "real nitric oxide" to the circulation. In the present study, we measured the acute effects of this supplement on blood nitrate/nitrite and hemodynamic variables. Ten resistance trained men (26 ± 4 years old; 8 ± 6 years of resistance exercise training) reported to the laboratory in random order after a 10-hour overnight fast on 2 occasions separated by 1 week and were provided the supplement (2-[nitrooxy]ethyl 2-amino-3-methylbutanoate) or placebo. Heart rate and blood pressure were recorded, and venous blood samples were collected before and at 5, 15, 30, and 60 minutes after complete breakdown of the supplement (5 minutes post intake) or placebo. Blood samples were assayed for plasma nitrate/nitrite. No interaction (p = 0.99), condition (p = 0.18), or time (p = 0.98) effects were noted for plasma nitrate/nitrite, with values remaining nearly identical across time for placebo (?27 ?mol·L(-1)) and increasing a maximum of ?6.7% (from 32.9 to 35.1 ?mol·L(-1)) at the 15-minute collection period for the supplement. In regards to hemodynamic variables, no interaction, condition, or time effects were noted for heart rate, systolic, or diastolic blood pressure (p > 0.05), with values near identical between conditions and virtually unchanged across time. These findings indicate that 2-(nitrooxy)ethyl 2-amino-3-methylbutanoate has a small effect on increasing circulating nitrate/nitrite and does not cause any change in hemodynamic variables within the 1 hour postingestion period in a sample of resistance trained men. PMID:20885188

  13. Mitral Valve Prolapse

    MedlinePLUS

    ... and ventricle, separated by the tricuspid (tri-CUSS-pid) valve. With each heartbeat, the atria contract and ... heart pumps blood and how your heart's electrical system works. Mitral Valve Prolapse In MVP, when the ...

  14. Valve Health Monitor (VHM)

    NASA Technical Reports Server (NTRS)

    Perotti, Jose M.; Delgado, H. (Technical Monitor)

    2002-01-01

    This presentation reports on progress being made on developing a Valve Health Monitor (VHM) Smart Current Signature Sensor. Topics cover include: design needs, target valves, current signatures, VHM design approach and VHM status/conclusions.

  15. Problem: Heart Valve Regurgitation

    MedlinePLUS

    ... the same amount of blood. Regurgitation occurs when: Blood flows back through the valve as the leaflets are ... flow in two directions during the contraction. Some blood flows from the ventricle through the aortic valve – as ...

  16. Pump isolation valve

    DOEpatents

    Kinney, Calvin L. (Penn Hills, PA); Wetherill, Todd M. (Lower Burrell, PA)

    1983-08-02

    The pump isolation valve provides a means by which the pump may be selectively isolated from the remainder of the coolant system while being compatible with the internal hydraulic arrangement of the pump during normal operation of the pump. The valve comprises a valve cylinder disposed around the pump and adjacent to the last pump diffuser with a turning vane attached to the lower end of the valve cylinder in a manner so as to hydraulically match with the discharge diffuser. The valve cylinder is connected to a drive means for sliding the valve cylinder relative to the diffuser support cylinder so as to block flow in either direction through the discharge diffuser when the valve is in the closed position and to aid in the flow of the coolant from the discharge diffuser by means of the turning vane when the valve is in the open position.

  17. Exercise performance and cardiovascular health variables in 70-year-old male soccer players compared to endurance-trained, strength-trained and untrained age-matched men.

    PubMed

    Randers, Morten Bredsgaard; Andersen, Jesper L; Petersen, Jesper; Sundstrup, Emil; Jakobsen, Markus D; Bangsbo, Jens; Saltin, Bengt; Krustrup, Peter

    2014-01-01

    The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65-85 years underwent a testing protocol including measurements of cycle performance, maximal oxygen uptake (VO2max) and body composition, and muscle fibre types and capillarisation were determined from m. vastus lateralis biopsy. In SP, time to exhaustion was longer (16.3 ± 2.0 min; P < 0.01) than in UT (+48%) and ST (+41%), but similar to ET (+1%). Fat percentage was lower (P < 0.05) in SP (-6.5% points) than UT but not ET and ST. Heart rate reserve was higher (P < 0.05) in SP (104 ± 16 bpm) than UT (+21 bpm) and ST (+24 bpm), but similar to ET (+2 bpm), whereas VO2max was not significantly different in SP (30.2 ± 4.9 ml O2 · min(-1) · kg(-1)) compared to UT (+14%) and ST (+9%), but lower (P < 0.05) than ET (-22%). The number of capillaries per fibre was higher (P < 0.05) in SP than UT (53%) and ST (42%) but similar to ET. SP had less type IIx fibres than UT (-12% points). In conclusion, the exercise performance and cardiovascular health profile are markedly better for lifelong trained SP than for age-matched UT controls. Incremental exercise capacity and muscle aerobic capacity of SP are also superior to lifelong ST athletes and comparable to endurance athletes. PMID:24787613

  18. Nonlinear System Modeling, Optimal Cam Design, and Advanced System Control for an Electromechanical Engine Valve Drive

    E-print Network

    Qiu, Yihui

    A cam-based shear force-actuated electromechanical valve drive system offering variable valve timing in internal combustion engines was previously proposed and demonstrated. To transform this concept into a competitive ...

  19. Lightweight Motorized Valve

    NASA Technical Reports Server (NTRS)

    Gonzalez, R.; Vandewalle, J.

    1986-01-01

    Redesigned actuator assembly weighs 50 percent less. Isolator valve operated by ac motor instead of usual dc solenoid. Valve weighs only 3 lb (1.4 kg). New valve functions with either two-phase or three-phase power. Developed for isolating fluids in propellant tanks, manifolds, and interconnecting lines of Space Shuttle reaction control and orbital maneuvering subsystems, valve suited to applications in which leakage must be kept to minimum at high pressure differences - in petroleum and chemical processing.

  20. Overflow control valve

    DOEpatents

    Hundal, Rolv (Hempfield, PA); Kessinger, Boyd A. (Murrysville, PA); Parlak, Edward A. (North Huntingdon, PA)

    1984-07-24

    An overflow control valve for use in a liquid sodium coolant pump tank which valve can be extended to create a seal with the pump tank wall or retracted to break the seal thereby accommodating valve removal. An actuating shaft which controls valve disc position also has cams which bear on roller surfaces to force retraction of a sliding cylinder against spring tension to retract the cylinder from sealing contact with the pump tank.

  1. Valve technology: A compilation

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A technical compilation on the types, applications and modifications to certain valves is presented. Data cover the following: (1) valves that feature automatic response to stimuli (thermal, electrical, fluid pressure, etc.), (2) modified valves changed by redesign of components to increase initial design effectiveness or give the item versatility beyond its basic design capability, and (3) special purpose valves with limited application as presented, but lending themselves to other uses with minor changes.

  2. Aerodynamic Shutoff Valve

    NASA Technical Reports Server (NTRS)

    Horstman, Raymond H.

    1992-01-01

    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.

  3. Stemless Ball Valve

    NASA Technical Reports Server (NTRS)

    Burgess, Robert K.; Yakos, David; Walthall, Bryan

    2012-01-01

    This invention utilizes a new method of opening and closing a ball valve. Instead of rotating the ball with a perpendicular stem (as is the case with standard ball valves), the ball is rotated around a fixed axis by two guide pins. This innovation eliminates the leak point that is present in all standard ball valves due to the penetration of an actuation stem through the valve body. The VOST (Venturi Off-Set-Technology) valve has been developed for commercial applications. The standard version of the valve consists of an off-set venturi flow path through the valve. This path is split at the narrowest portion of the venturi, allowing the section upstream from the venturi to be rotated. As this rotation takes place, the venturi becomes restricted as one face rotates with respect to the other, eventually closing off the flow path. A spring-loaded seal made of resilient material is embedded in the upstream face of the valve, making a leak-proof seal between the faces; thus a valve is formed. The spring-loaded lip seal is the only seal that can provide a class six, or bubble-tight, seal against the opposite face of the valve. Tearing action of the seal by high-velocity gas on this early design required relocation of the seal to the downstream face of the valve. In the stemless embodiment of this valve, inner and outer magnetic cartridges are employed to transfer mechanical torque from the outside of the valve to the inside without the use of a stem. This eliminates the leak path caused by the valve stems in standard valves because the stems penetrate through the bodies of these valves.

  4. Gas lift valve

    SciTech Connect

    Hamm, E.J.

    1986-06-03

    A gas lift valve is described which consists of: a body, a main valve seat in the body, a main valve member cooperable with the seat to control flow through the body, a pressure dome including a depending bellows connected to the valve member, the bellows being exposed to pressure within the dome urging the valve member toward the seat and to pressure exterior of the body urging the valve member away from the seat, an internal valve seat between the bellows and the remainder of the dome, an internal valve member separate from and movable relative to and supported on the main valve member and cooperable with the internal valve seat to control flow therethrough, one of the internal valve member and seat constructed of polyimide material, hydraulic fluid in the dome extending to a level above the internal valve seat, and a sleeve of polyimide material having a sliding engagement with the interior of the bellows and supporting the bellows against distortion when subjected to a differential pressure thereacross.

  5. Dual flapper valve assembly

    SciTech Connect

    Clary, S.R.; Giusti, F. Jr.; Sproul, R.M.

    1989-07-11

    This patent describes a dual flapper valve assembly for limiting the loss of completion fluid in connection with a well service operation. The valve assembly consists of: tubular support means defining a flow passage; a first flapper valve assembly connected in series flow relation with the support means, the first flapper valve assembly having a valve closure member movable between first and second positions for closing and opening the flow passage; a second flapper valve assembly connected in series flow relation in the support means, the second flapper valve assembly having a valve closure member movable between open and closed passage positions for closing and opening the flow passage; a prop sleeve mounted within the support means, the prop sleeve being movable from an extended position in which it props the closure member of one flapper valve in the open passage position to a retracted position in which the closure member is disengaged and released for movement to the closed passage position, the valve closure member of one of the flapper valve assemblies being engageable by a wash pipe extending through the flow passage to prop the valve closure member in the open passage position, and being movable to the closed passage position upon retraction of the wash pipe out of the flow passage.

  6. Heart valve tissue engineering

    Microsoft Academic Search

    Stefan Neuenschwander; Simon P. Hoerstrup

    2004-01-01

    Valvular heart disease is a significant cause of morbidity and mortality world-wide. Classical replacement surgery involves the implantation of mechanical valves or biological valves (xeno- or homografts). Tissue engineering of heart valves represents a new experimental concept to improve current modes of therapy in valvular heart surgery. Various approaches have been developed differing either in the choice of scaffold (synthetic

  7. Microblower assisted barometric valve

    DOEpatents

    Rossabi, Joseph; Hyde, Warren K.; Riha, Brian D.; Jackson, Dennis G.; Sappington, Frank

    2005-12-06

    A gas exchange apparatus is provided which provides for both passive fluid flow and blower associated fluid flow through a barometric valve. A battery powered blower is provided which allows for operation of the barometric valve during times when the barometric valve would otherwise be closed, and provides for enhanced volume of gas exchange.

  8. Lock For Valve Stem

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Guirguis, Kamal S.

    1991-01-01

    Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

  9. Semiactive compressor valve

    Microsoft Academic Search

    Klaus Brun; Ryan S. Gernentz

    2010-01-01

    A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an

  10. Mitral Valve Prolapse

    MedlinePLUS

    Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of the valve are "floppy" and ... to run in families. Most of the time, MVP doesn't cause any problems. Rarely, blood can ...

  11. Heart Valve Diseases

    MedlinePLUS

    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 ...

  12. Liquid rocket valve assemblies

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The design and operating characteristics of valve assemblies used in liquid propellant rocket engines are discussed. The subjects considered are as follows: (1) valve selection parameters, (2) major design aspects, (3) design integration of valve subassemblies, and (4) assembly of components and functional tests. Information is provided on engine, stage, and spacecraft checkout procedures.

  13. Mitral Valve Repair

    MedlinePLUS

    ... heart procedure performed by cardiothoracic surgeons to treat stenosis (narrowing) or regurgitation (leakage) of the mitral valve. The mitral valve is the "inflow valve" for the left side of the heart. Blood flows from the lungs, where it picks up oxygen, ...

  14. Pressure regulating valve controller

    Microsoft Academic Search

    1988-01-01

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

  15. Heart Valve Disease

    MedlinePLUS

    ... and affect its ability to pump blood. Overview How the Heart Valves Work At the start of each heartbeat, blood returning ... and detailed animations, go to the Health Topics How the Heart Works article. Heart Valve Problems Heart valves can have ...

  16. An experimental method for validating compressor valve vibration theory

    NASA Astrophysics Data System (ADS)

    Habing, R. A.; Peters, M. C. A. M.

    2006-07-01

    This paper presents an experimental method for validating traditional compressor valve theory for unsteady flow conditions. Traditional valve theory considers the flow force acting on the plate and the flow rate as quasi-steady variables. These variables are related via semi-empirical coefficients which are determined by steady flow experiments. The new experimental methodology permitted the simultaneous measurement of instantaneous valve opening, instantaneous volume-flow rate and instantaneous pressure difference across the valve. Results for an oscillating valve (at 1.9 times the valve resonance frequency) show that the gas force is predicted reasonably accurately. However, the flow rate model should be improved in order to predict the observed hysteresis (30%) and fluctuations in the vena contracta factor.

  17. Surface controlled subsurface safety valve

    SciTech Connect

    Adams, J.B. Jr.

    1984-02-14

    A surface controlled subsurface safety valve is disclosed for deep well service. Communication of control fluid to the subsurface safety valve is controlled by a pilot valve at a subsurface location in close proximity to the safety valve. Responsiveness of the subsurface safety valve to decrease in control fluid pressure is thereby increased and the safety valve's closure speed is also increased. The pilot valve controllably communicates pressurized control fluid to open the safety valve and allows control fluid to be displaced into the flow path through the safety valve during valve closure.

  18. Model based Estimation of Aortic and Mitral valves Opening and Closing Timings in Developing Human Fetuses.

    PubMed

    Marzbanrad, Faezeh; Kimura, Yoshitaka; Endo, Miyuki; Oshio, Sayaka; Funamoto, Kiyoe; Sato, Naoaki; Palaniswami, Marimuthu; Khandoker, Ahsan

    2014-10-16

    Electromechanical coupling of the fetal heart can be evaluated non-invasively using Doppler Ultrasound (DUS) signal and fetal electrocardiography (fECG). In this study, an efficient model is proposed using K-means clustering and hybrid SVM-HMM modeling techniques. Opening and closing of the cardiac valves were detected from peaks in the high frequency component of the DUS signal decomposed by wavelet analysis. It was previously proposed to automatically identify the valve motion by hybrid Support Vector Machine- Hidden Markov Model (SVM-HMM) [1] based on the amplitude and timing of the peaks. However, in the present study, six patterns were identified for the DUS components which were actually variable on a beat to beat basis and found to be different for the early gestation (16- 32 weeks), compared to the late gestation fetuses (36-41 weeks). The amplitude of the peaks linked to the valve motion was different across the six patterns and this affected the precision of valve motion identification by the previous hybrid SVM-HMM method. Therefore in the present study, clustering of the DUS components based on K-means was proposed and the hybrid SVM-HMM was trained for each cluster separately. The valve motion events were consequently identified more efficiently by beat-to-beat attribution of the DUS component peaks. Applying this method, more than 98.6% of valve motion events were beatto- beat identified with average precision and recall of 83.4% and 84.2% respectively. It was an improvement compared to the hybrid method without clustering with average precision and recall of 79.0% and 79.8%. Therefore, this model would be useful for reliable screening of fetal wellbeing. PMID:25343774

  19. Well pipe float valve

    SciTech Connect

    Taylor, J.S.

    1986-11-18

    This patent describes a drill pipe float assembly comprising an elongated cylindrical cage having upper and lower rings joined by diametrically opposite vertical wall members. The upper ring has a downwardly facing valve seat on its inner perimeter. The assembly includes a valve stem guide member supported by the lower ring including a central vertical bearing sleeve slidable guiding the depending end portion of a valve stem. The valve stem has a valve on its upper end including an elastomer seal seating and unseating on the valve seat in response to the direction of fluid flow through the ring members, cylindrical spring retainer on the valve stem in contact with the valve seal, and a helical spring surrounding the valve stem and biasing the valve toward its seat, the improvement comprising: means secured to the respective confronting end surfaces of the spring retainer and the valve stem guide sleeve for interdigitated engagement in response to fluid flow in one direction through the float assembly.

  20. Differential fill valve assembly

    SciTech Connect

    Freeman, T. A.

    1984-10-02

    A differential fill valve assembly for application in float collars or shoes in well casing. The valve assembly comprises a back pressure flapper valve disposed within a substantially tubular upper housing, and a lower housing containing an activating sleeve slidably disposed therein above a double flapper valve assembly. The activating sleeve initially extends into the upper housing to a sufficient extent to maintain the flapper valve in an open position; the activating sleeve is maintained in this position through use of shear pins, by which it is secured to the lower housing. The double flapper valve comprises a first flapper responsive to pressure below the valve assembly, and a second flapper responsive to force applied from above. A tripping ball is dropped to seat in the activating sleeve when it is desired to release the back pressure flapper valve; pressure applied on the ball moves the activating sleeve downward, releasing the back pressure flapper valve and swinging the double flapper valve assembly out of the flow path through the differential fill assembly, after which the tripping ball exits the bottom of the assembly. A lock ring maintains the activating sleeve in its lower position, while a shear screw riding in a longitudinal channel in the lower housing prevents rotation of the activating sleeve during its longitudinal movement prior to its contacting the double flapper valve assembly.

  1. Simulation of a Hydraulic Pump Control Valve

    NASA Technical Reports Server (NTRS)

    Molen, G. Vander; Akers, A.

    1987-01-01

    This paper describes the mode of operation of a control valve assembly that is used with a hydraulic pump. The operating system of the valve is modelled in a simplified form, and an analogy for hydraulic resonance of the pressure sensing system is presented. For the control valve investigated, air entrainment, length and diameter of the resonator neck, and valve mass produced the greatest shift in resonant frequency. Experimental work was conducted on the hydraulic system so that the resonance levels and frequencies could be measured and the accuracy of the theory verified. The results obtained make it possible to evaluate what changes to any of the variables considered would be most effective in driving the second harmonic frequency above the operating range.

  2. The effects of concurrent training on performance variables in previously untrained males

    E-print Network

    Glowacki, Shawn Philip

    2005-02-17

    to this investigation. Similarly, Dudley and Djamil (14) showed that the concurrent and resistance only groups had similar maximum isokinetic knee-extension torque improvements at low velocities (0 - 96.3 deg/sec), but the groups differed at the higher velocities... and Djamil (14) showed slightly different results. This study showed that the concurrent and resistance training only groups had similar improvements in maximal-isokinetic knee extension torque at low velocities (0 - 96.3 deg/sec). However, the groups...

  3. Variable venturi type carburetor

    SciTech Connect

    Tahata, M.

    1986-09-02

    A variable venturi type carburetor is described comprising a carburetor body provided with a suction passage therein for flow of air through the passage, a slide valve supported by the body for slidable movement across the suction passage to serve as a variable venturi, a butterfly throttle valve pivotably supported by the carburetor body downstream of the slide valve, interlocking means connecting the slide valve and the butterfly throttle valve together for operating in correspondence with one another, operating means connected to one of the valves for operating the same by application of an external force thereto. A low-speed fuel nozzle opens into the suction passage in the vicinity of the butterfly throttle valve, an intermediate and a high speed main fuel nozzle opens into the suction passage opposite the slide valve, and a low and intermediate-speed primary fuel nozzle opens into the suction passage between the slide valve and the butterfly throttle valve. The slide valve includes a bottom portion having a front side surface facing upstream in the suction passage and a rear side surface facing downstream in the suction passage, the front and rear side surfaces having lower edges which are located in the same horizontal plane, the rear side surface being provided with an inverted cutaway.

  4. Dome pressure maintaining valve

    SciTech Connect

    Snyder, D.E.

    1990-12-04

    This patent describes a system for maintaining dome fluid pressure in a pilot operated relief valve. It comprises: a fluid pressure maintenance means having an inlet port for receiving pressurized fluid supply from a source requiring pressure relief maintenance and an outlet port for expelling the pressurized fluid from the fluid pressure maintenance means; the fluid pressure maintenance means being placed in a circuit between a sensor inlet and the pilot valve, means capable of being adapted with fixed or adjustable pressure setting functionality; the fluid pressure maintenance means outlet port in communication with a dome of the relief valve through the pilot; the fluid pressure maintenance means functioning through a poppet check valve for equalizing inlet and outlet pressure. The poppet check valve providing inlet flow and check for reverse flow; the poppet check valve and a piston valve integrated into one piston valve embodiment with the piston valve providing outlet flow in a backflow relief mode; and the fluid pressure maintenance means having a pressure storage chamber for providing a maintaining fluid pressure in the relief valve dome.

  5. CAM operated fuel valve

    SciTech Connect

    Kelly, S.T.; Katchka, J.R.

    1991-09-03

    This patent describes improvement in a fuel control valve construction comprising a housing means having an inlet means adapted to be interconnected to a fuel source and a main outlet means adapted to be interconnected to a main burner means, the housing means having a main valve seat for interconnecting the inlet means with the main outlet means, the housing means having a movable main valve member for opening and closing the main valve seat, the housing means having a movable lever operatively associated with the main valve member and having a manually operable actuator means for controlling the operating positions of the lever, the lever having an intermediate cam follower portion and opposed ends disposed on each side of the cam follower portion with one end of the opposed ends being pivotally mounted to the housing means and with the other end of the opposed ends for operating the main valve member, the housing means having biasing means operatively interconnected to the lever to tend to pivot the lever in one direction that opens the main valve member away from its the main valve seat. The improvement comprises; the housing means has a thermostatically controlled means that is operatively associated with the lever and is adapted to engage and hold the lever in a position wherein the main valve member is in a closed condition against its the main valve seat when the thermostatically controlled means is in one operating condition thereof and the actuator means is in the on condition thereof.

  6. Surface controlled subsurface safety valve

    SciTech Connect

    Rumbaugh, W.D.; Waters, F.A.

    1987-05-26

    A pilot valve is described for operating a subsurface safety valve installed in a well production string comprising: a pilot valve housing; locking assembly means connected with the housing for releasably locking the housing in a receptacle along the production string near the subsurface safety valve; first flow passage means in the housing for flow connection with a surface control fluid line extending to the subsurface safety valve; port means in the housing for communication with the production string above the subsurface safety valve; second flow passage means in the housing in communication with the port means; a flow control valve in the housing between the first and second flow passage means; an electrical valve operator in the housing connected with the flow control valve for opening and closing the flow control valve independently of the surface controlled fluid line to the subsurface valve; and electrical conducting means connected with the valve operator for supplying electrical power to the valve operator.

  7. Options for Heart Valve Replacement

    MedlinePLUS

    ... the damaged valve aortic valve TAVI/TAVR procedure — Transcatheter aortic valve replacement Newer surgery options The procedure chosen will depend ... on to live a full and healthy life. Mitral valve repair can often provide a ... replacements. Aortic valve replacement is more likely to require ...

  8. Heart Valve Disease

    Microsoft Academic Search

    Ranjit John; Kenneth K. Liao

    \\u000a This chapter was designed to provide the reader with a brief overview of the current surgical treatment options for heart\\u000a valve disease. Major topics of discussion are: (1) development of prosthetic valve replacements; (2) current issues with valve\\u000a replacement; (3) major valvular diseases that affect humans in the Western world; and (4) recent advances in therapeutic options\\u000a for valvular diseases.

  9. Standing and injection valve

    SciTech Connect

    Williamson, J.R. Jr.

    1988-08-30

    A standing valve is described operable as an injection valve comprising: (a) a housing having a longitudinal flow passage therethrough and at least one lateral flow passage through the housing wall communicating between the longitudinal flow passage and the housing exterior; (b) annular valve means in the housing for controlling flow through the lateral passage including an annular valve member mounted within the housing and a longitudinally movable annular seat member sealingly engageable with the valve member; (c) operator means connected to the seat member for moving the seat member between an open position, disengaging from the valve member and permitting flow between the housing passage and exterior, and a closed position, engaging with the valve member and preventing flow between the passage and the exterior; (d) control means for controlling operator means pressure required to move the seat member to open position; and (e) check valve means in the housing below the annular valve means permitting upward flow and preventing downward flow through the longitudinal passage.

  10. Lined 10'' butterfly valve outlasts competitive valves in brine filter system

    SciTech Connect

    Gaines, A.

    1982-03-01

    One of the world's largest chlorine production units located in the Gulf Coast area has an extensive brine piping system with a large number of valves. Some of the valves performed well but many failed to meet the service requirements, especially in the brine filtering system with the salt solution at ambient temperatures and pressures about 100 psi. One of these was a 10'' valve. Various types of gear-operated butterfly valves, with an elastomer lining to withstand the somewhat corrosive solution, had been tried but developed leaks and had to be repaired or replaced after 4 to 6 months. The valves became difficult or impossible to operate in some cases when brine leaking past the stem seal attacked the inner surface of the metal valve body and the liner was dislodged by the movement of the disc. In September 1980, a 10'' butterfly valve specifically designed for bubble-tight shut off and zero stem leakage was installed in the brine filter line on a trial basis. The valve has a 1-piece, epoxy-coated ductile iron body with a molded one-piece liner of Hypalon rubber, and a stainless steel stem and disc with splines instead of pins to provide a trouble-free connection. The stem is positively sealed against leakage by a patented spherical machining process on both the disc and the liner. The valve was furnished with a variable ratio gear actuator that has higher torque output when the disc begins to make contact with the seat to assure a bubble-tight shutoff with minimum input torque. The butterfly valve has provided leaktight performance since it was installed in September 1980 and is still easy to open and close by the geared actuator.

  11. A low power, on demand electrothermal valve for wireless drug delivery applications

    E-print Network

    Meng, Ellis

    limiter, was added into the valve circuit to provide variable current ramping. Wireless activation) coils for power. Activation of the valve occurs over a period referred to as the time constant9A low power, on demand electrothermal valve for wireless drug delivery applications Po-Ying Li

  12. NOTES ON EXPERIMENTAL TECHNIQUE AND APPARATUS: Capillary-type regulating valves for gas flows

    Microsoft Academic Search

    W. Snelleman

    1966-01-01

    A valve for the regulation of gas flows in the range of 1-50 l. min-1, combined with reliable shut-off, is described. The principle is the use of a capillary of variable length. The valve is more reliable than the usual needle valves.

  13. Recently patented transcatheter aortic valves in clinical trials.

    PubMed

    Neragi-Miandoab, Siyamek; Skripochnik, Edvard; Salemi, Arash; Girardi, Leonard

    2013-12-01

    The most widely used heart valve worldwide is the Edwards Sapien, which currently has 60% of the worldwide transcatheter aortic valve implantation (TAVI) market. The CoreValve is next in line in popularity, encompassing 35% of the worldwide TAVI market. Although these two valves dominate the TAVI market, a number of newer transcatheter valves have been introduced and others are in early clinical evaluation. The new valves are designed to reduce catheter delivery diameter, improve ease of positioning and sealing, and facilitate repositioning or removal. The most recent transcatheter valves for transapical use include Acurate TA (Symetis), Engager (Medtronic), and JenaValve the Portico (St Jude), Sadra Lotus Medical (Boston Scientific), and the Direct Flow Medical. These new inventions may introduce more effective treatment options for high-risk patients with severe aortic stenosis. Improvements in transcatheter valves and the developing variability among them may allow for more tailored approaches with respect to patient's anatomy, while giving operators the opportunity to choose devices they feel more comfortable with. Moreover, introducing new devices to the market will create a competitive environment among producers that will reduce high prices and expand availability. The present review article includes a discussion of recent patents related to Transcatheter Aortic Valves. PMID:24279506

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

    ClinicalTrials.gov

    2014-08-08

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

  15. Variability and information content in auditory cortex spike trains during an interval-discrimination task.

    PubMed

    Abolafia, Juan M; Martinez-Garcia, M; Deco, G; Sanchez-Vives, M V

    2013-11-01

    Processing of temporal information is key in auditory processing. In this study, we recorded single-unit activity from rat auditory cortex while they performed an interval-discrimination task. The animals had to decide whether two auditory stimuli were separated by either 150 or 300 ms and nose-poke to the left or to the right accordingly. The spike firing of single neurons in the auditory cortex was then compared in engaged vs. idle brain states. We found that spike firing variability measured with the Fano factor was markedly reduced, not only during stimulation, but also in between stimuli in engaged trials. We next explored if this decrease in variability was associated with an increased information encoding. Our information theory analysis revealed increased information content in auditory responses during engagement compared with idle states, in particular in the responses to task-relevant stimuli. Altogether, we demonstrate that task-engagement significantly modulates coding properties of auditory cortical neurons during an interval-discrimination task. PMID:23945780

  16. Use of a Melody Pulmonary Valve in Transcatheter Valve-in-Valve Replacement for Tricuspid Valve Bioprosthesis Degeneration

    PubMed Central

    Snipelisky, David F.; Shapiro, Brian P.

    2014-01-01

    Bioprosthetic heart valves can degenerate and fail over time. Repeat surgery as a means of replacement increases morbidity and mortality rates, and some patients are not candidates for reoperation. A newer treatment, percutaneous transcatheter valve-in-valve implantation, might delay or substitute for invasive procedures. We present the case of a 51-year-old woman, a poor candidate for surgery who had prosthetic tricuspid valve degeneration and stenosis. We successfully performed valve-in-valve placement of a Melody® valve, using a procedure originally intended to treat pulmonary valve conduit obstruction or regurgitation. To our knowledge, this is among the first case reports to describe the use of the Melody pulmonary valve in transcatheter valve-in-valve replacement for prosthetic tricuspid stenosis that was otherwise not correctable. Additional data and longer follow-up periods are necessary to gain an understanding of ideal indications and selection of patients for the percutaneous transcatheter treatment of tricuspid valve stenosis. PMID:25425984

  17. Mitral valve surgery - minimally invasive

    MedlinePLUS

    ... remove your mitral valve and sew a new one into place. There are two main types of new valves: Mechanical -- made of man-made materials, such as titanium and carbon. These valves last the longest. You ...

  18. Aortic valve surgery - minimally invasive

    MedlinePLUS

    ... remove your aortic valve and sew a new one into place. There are two main types of new valves: Mechanical -- made of man-made materials, such as titanium or carbon. These valves last the longest. You ...

  19. Correlation of Exhaust-Valve Temperatures with Engine Operating Conditions and Valve Design in an Air-Cooled Cylinder

    NASA Technical Reports Server (NTRS)

    Zipkin, M A; Sanders, J C

    1945-01-01

    A semiempirical equation correlating exhaust-valve temperatures with engine operating conditions and exhaust-valve design has been developed. The correlation is based on the theory correlating engine and cooling variables developed in a previous NACA report. In addition to the parameters ordinarily used in the correlating equation, a term is included in the equation that is a measure of the resistance of the complex heat-flow paths between the crown of the exhaust valve and a point on the outside surface of the cylinder head. A means for comparing exhaust valves of different designs with respect to cooling is consequently provided. The necessary empirical constants included in the equation were determined from engine investigations of a large air-cooled cylinder. Tests of several valve designs showed that the calculated and experimentally determined exhaust-valve temperatures were in good agreement.

  20. Non-plugging injection valve

    DOEpatents

    Carey, Jr., Henry S. (Wilsonville, AL)

    1985-01-01

    A valve for injecting fluid into a conduit carrying a slurry subject to separation to form deposits capable of plugging openings into the conduit. The valve comprises a valve body that is sealed to the conduit about an aperture formed through the wall of the conduit to receive the fluid to be injected and the valve member of the valve includes a punch portion that extends through the injection aperture to the flow passage, when the valve is closed, to provide a clear channel into the conduit, when the valve is opened, through deposits which might have formed on portions of the valve adjacent the conduit.

  1. Safety check valve

    Microsoft Academic Search

    Spears

    1992-01-01

    This patent describes a safety check valve, for use with a pumping unit for petroleum fluids, the pumping unit including a polished rod and a stuffing box. It comprises: a valve housing having upper and lower ends and a central bore extending between the upper and lower ends and adapted to have the polished rod pass through the central bore;

  2. Mud separator valve apparatus

    Microsoft Academic Search

    1981-01-01

    An automatic cleaning system is provided for a mud separator apparatus. Water and mud inputs to a mud pump feeding the separator are respectively controlled by two butterfly valves ganged for cooperation, and operated by a single valve actuator motor. When the mud separator is shut off, a time delay relay is actuated which keeps the mud separator rotor motor

  3. Linear motion valve

    NASA Technical Reports Server (NTRS)

    Chandler, J. A. (inventor)

    1985-01-01

    The linear motion valve is described. The valve spool employs magnetically permeable rings, spaced apart axially, which engage a sealing assembly having magnetically permeable pole pieces in magnetic relationship with a magnet. The gap between the ring and the pole pieces is sealed with a ferrofluid. Depletion of the ferrofluid is minimized.

  4. Well control valve apparatus

    Microsoft Academic Search

    Crowe

    1977-01-01

    A well control valve is disclosed which is installed in a tubing string for use in killing a well through use of fluid under pressure pumped down through the annulus surrounding the turing string. When the ammulus pressure exceeds a predetermined value, the valve is opened to permit the kill fluid to flow into and though the tubing string into

  5. Shutoff and throttling valve

    NASA Technical Reports Server (NTRS)

    Hays, L. G.

    1974-01-01

    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.

  6. Valve Repair or Replacement

    MedlinePLUS

    ... made from materials such as plastic, carbon, or metal. Mechanical valves are strong, and they last a long time. ... made of bovine (cow) pericardium supported by a metal stent. Also called TAVR (transcatheter aortic valve replacement), the FDA-approved TAVI procedure is only ...

  7. No Valve in Vain

    NSDL National Science Digital Library

    Techtronics Program,

    Acting as biomedical engineers, students design, build, test and redesign prototype heart valves using materials such as waterproof tape, plastic tubing, flexible plastic and foam sheets, clay, wire and pipe cleaners. They test them with flowing water, representing blood moving through the heart. As students creatively practice engineering problem solving, they demonstrate their understanding of how one-way heart valves work.

  8. Heimlich valve and pneumothorax

    PubMed Central

    Gogakos, Apostolos; Barbetakis, Nikolaos; Lazaridis, George; Papaiwannou, Antonis; Karavergou, Anastasia; Lampaki, Sofia; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Kioumis, Ioannis; Pitsiou, Georgia; Katsikogiannis, Nikolaos; Tsakiridis, Kosmas; Rapti, Aggeliki; Trakada, Georgia; Zissimopoulos, Athanasios; Tsirgogianni, Katerina; Zarogoulidis, Konstantinos

    2015-01-01

    The Heimlich valve is a small one-way valve used for chest drainage that empties into a flexible collection device and prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation. Currently there are several systems in the market. It can be used in many patients instead of a traditional water seal drainage system. The Heimlich chest drainage valve was developed so that the process of draining the pleural cavity could be accomplished in a safe, relatively simple, and efficient manner. This valve system has replaced the cumbersome underwater drainage bottle system. Moreover; the Heimlich valve system connects to chest tubing and allows fluid and air to pass in one direction only. This system functions in any position, and it does not ever need to be clamped, a regulated suction can be attached to it if necessary. The valve drains into a plastic bag that can be held at any level, allowing the patient undergoing chest drainage to be ambulatory simply by carrying the bag. In the current mini review we will present the Heimlich valve system and method of insertion.

  9. Heimlich valve and pneumothorax.

    PubMed

    Gogakos, Apostolos; Barbetakis, Nikolaos; Lazaridis, George; Papaiwannou, Antonis; Karavergou, Anastasia; Lampaki, Sofia; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Kioumis, Ioannis; Pitsiou, Georgia; Katsikogiannis, Nikolaos; Tsakiridis, Kosmas; Rapti, Aggeliki; Trakada, Georgia; Zissimopoulos, Athanasios; Tsirgogianni, Katerina; Zarogoulidis, Konstantinos; Zarogoulidis, Paul

    2015-03-01

    The Heimlich valve is a small one-way valve used for chest drainage that empties into a flexible collection device and prevents return of gases or fluids into the pleural space. The Heimlich valve is less than 13 cm (5 inches) long and facilitates patient ambulation. Currently there are several systems in the market. It can be used in many patients instead of a traditional water seal drainage system. The Heimlich chest drainage valve was developed so that the process of draining the pleural cavity could be accomplished in a safe, relatively simple, and efficient manner. This valve system has replaced the cumbersome underwater drainage bottle system. Moreover; the Heimlich valve system connects to chest tubing and allows fluid and air to pass in one direction only. This system functions in any position, and it does not ever need to be clamped, a regulated suction can be attached to it if necessary. The valve drains into a plastic bag that can be held at any level, allowing the patient undergoing chest drainage to be ambulatory simply by carrying the bag. In the current mini review we will present the Heimlich valve system and method of insertion. PMID:25861609

  10. Mitral Valve Prolapse

    MedlinePLUS

    ... to limit participation in competitive sports. If your mitral valve prolapse causes chest pain or other symptoms, your doctor might prescribe medicines such as beta blockers to make your symptoms better. ... valve prolapse, infection (called bacterial endocarditis) can occur in the ...

  11. Energy Savings Potential of Process Control Valve Replacement

    E-print Network

    Holzenthal, L. Jr.

    candidates for savings. A feasibility study of retrofitting a pipeline flow control system, currently operating with a constant speed pump and differential producing, modulating control valve, with a variable speed drive is presented. This case study...

  12. Multiple-port valve

    DOEpatents

    Doody, Thomas J. (Downers Grove, IL)

    1978-08-22

    A multiple-port valve assembly is designed to direct flow from a primary conduit into any one of a plurality of secondary conduits as well as to direct a reverse flow. The valve includes two mating hemispherical sockets that rotatably receive a spherical valve plug. The valve plug is attached to the primary conduit and includes diverging passageways from that conduit to a plurality of ports. Each of the ports is alignable wih one or more of a plurality of secondary conduits fitted into one of the hemispherical sockets. The other hemispherical socket includes a slot for the primary conduit such that the conduit's motion along that slot with rotation of the spherical plug about various axes will position the valve-plug ports in respect to the secondary conduits.

  13. Boston Scientific Lotus valve.

    PubMed

    Meredith, Ian T; Hood, Kristin L; Haratani, Nicole; Allocco, Dominic J; Dawkins, Keith D

    2012-09-01

    As a result of recent randomised controlled trials and registry observations, transcatheter aortic valve replacement (TAVR) enjoys growing appeal for the treatment of patients at high or extreme risk from surgical aortic valve replacement. However, the current technologies and techniques have important limitations, including risk of stroke, vascular complications and paravalvular aortic regurgitation, which may in turn influence survival. While careful patient selection and screening may improve outcomes, new valve designs and iterations are required. The Lotus aortic valve replacement system is a new fully repositionable device designed to facilitate more precise delivery and minimise paravalvular regurgitation. The safety and efficacy of the Lotus valve are being studied systematically in the REPRISE clinical trial programme. PMID:22995115

  14. Serial correlation in neural spike trains: Experimental evidence, stochastic modeling, and single neuron variability

    NASA Astrophysics Data System (ADS)

    Farkhooi, Farzad; Strube-Bloss, Martin F.; Nawrot, Martin P.

    2009-02-01

    The activity of spiking neurons is frequently described by renewal point process models that assume the statistical independence and identical distribution of the intervals between action potentials. However, the assumption of independent intervals must be questioned for many different types of neurons. We review experimental studies that reported the feature of a negative serial correlation of neighboring intervals, commonly observed in neurons in the sensory periphery as well as in central neurons, notably in the mammalian cortex. In our experiments we observed the same short-lived negative serial dependence of intervals in the spontaneous activity of mushroom body extrinsic neurons in the honeybee. To model serial interval correlations of arbitrary lags, we suggest a family of autoregressive point processes. Its marginal interval distribution is described by the generalized gamma model, which includes as special cases the log-normal and gamma distributions, which have been widely used to characterize regular spiking neurons. In numeric simulations we investigated how serial correlation affects the variance of the neural spike count. We show that the experimentally confirmed negative correlation reduces single-neuron variability, as quantified by the Fano factor, by up to 50%, which favors the transmission of a rate code. We argue that the feature of a negative serial correlation is likely to be common to the class of spike-frequency-adapting neurons and that it might have been largely overlooked in extracellular single-unit recordings due to spike sorting errors.

  15. Effects of aerobic training intensity on resting, exercise and post-exercise blood pressure, heart rate and heart-rate variability

    Microsoft Academic Search

    V A Cornelissen; B Verheyden; A E Aubert; R H Fagard

    2010-01-01

    We aimed to investigate the effects of endurance training intensity (1) on systolic blood pressure (SBP) and heart rate (HR) at rest before exercise, and during and after a maximal exercise test; and (2) on measures of HR variability at rest before exercise and during recovery from the exercise test, in at least 55-year-old healthy sedentary men and women. A

  16. Transcatheter valve-in-valve implantation for degenerated mitral valve bioprosthesis under 3D echocardiographic guidance.

    PubMed

    Lerakis, Stamatios; Hayek, Salim S; Thourani, Vinod; Babaliaros, Vasilis

    2014-09-01

    Transcatheter mitral valve-in-valve replacement is increasingly being performed as operator and center experience in transcatheter valve replacement technology and techniques have accrued. Complications, such as valve embolization and paravalvular regurgitation, still occur and relate to valve deployment. The use of novel imaging techniques, such as 3D echocardiography, allows for better differentiation of cardiac structures and appropriate positioning of the transcatheter valve using well-visualized anatomical landmarks. Here the authors describe in images and video the use of 3D echocardiography for deployment of a mitral valve-in-valve. PMID:25134981

  17. Modular, self-contained hydraulic valve timing systems for internal combustion engines

    SciTech Connect

    Wakeman, R.J.

    1989-12-19

    A modular self-contained hydraulic variable valve timing system for use with an internal combustion engine of the type having an engine block which includes a rotatable cam shaft, and sets of intake and exhaust valves respectively operatively associated with combustion cylinders of the engine. The modular self-contained variable valve timing system comprising: a valve cover adapted to being coupled to the engine block in covering relationship to the intake and exhaust valves. The valve cover having an integral case. The case including a first open-ended bore in opposing relationship to a cam of the cam shaft, and a second open-ended bore in opposing relationship to a valve stem of one of the intake and exhaust valves, and means which fluid-connect the first and second bores so as to establish a hydraulic transfer path therebetween; cam follower piston means received within, and closing, the first bore for following a profile of the cam and being reciprocally displaced within the first bore in response thereto; valve actuating piston means received within, and closing, the second bore and being in opposing relationship to the stem associated with the one valve; a control passageway in fluid communication with the hydraulic transfer path; and solenoid valve means fluid-connected to the control passageway and having first and second operative states for variably controlling timing and duration of the one valve opening.

  18. Stentless aortic valves. Current aspects.

    PubMed

    Ennker, J; Albert, A; Ennker, I C

    2012-01-01

    The design of stentless valve prostheses is intended to achieve a more physiological flow pattern and superior hemodynamics in comparison to stented valves. First - generation stentless bioprosthesis were the Prima valve, the Freestyle valve and the Toronto stentless porcine valve. The second generation of stentless valves, as the Super stentless aortic porcine valve, need only one suture line. The Sorin Pericarbon Freedom and the Equine 3F heart Valve belong to the third generation of stentless valve pericardial bioprostheses. A stentless valve to replace a full root can be implanted by several surgical techniques: complete or modified subcoronary, root inclusion and full root. The full root technique is accompanied by the lowest incidence of patient-prothesis mismatch. Our own clinical experience reflects more than 3000 stentless valve implantations since April 1996. Randomized study trials showed a hemodynamic advantage for stentless valves, but several could not reach a significant level. Also reported was a significant advantage of stentless bioprostheses concerning transvalvular gradients, effective valve area and quicker regression of the left ventricular mass 6 months after the operation, but at 12 months. Advantages are obvious in patients with a decreased left ventricle ejection fraction of less than 50% and in smaller implanted valve size, concomitant aortic root pathology (e.g. dissection) and aortic valve endocarditis. A survival advantage for stentless bioprostheses in comparison to stented ones has been reported by all studies in the literature. Stentless valves enrich the surgical armamentarium. Time will define the place of stentless valves in the future. PMID:23439732

  19. Effects of additional repeated sprint training during preseason on performance, heart rate variability, and stress symptoms in futsal players: a randomized controlled trial.

    PubMed

    Soares-Caldeira, Lúcio F; de Souza, Eberton A; de Freitas, Victor H; de Moraes, Solange M F; Leicht, Anthony S; Nakamura, Fábio Y

    2014-10-01

    The aim of this study was to investigate whether supplementing regular preseason futsal training with weekly sessions of repeated sprints (RS) training would have positive effects on repeated sprint ability (RSA) and field test performance. Thirteen players from a professional futsal team (22.6 ± 6.7 years, 72.8 ± 8.7 kg, 173.2 ± 6.2 cm) were divided randomly into 2 groups (AddT: n = 6 and normal training group: n = 7). Both groups performed a RSA test, Yo-Yo intermittent recovery test level 1 (YoYo IR1), squat (SJ) and countermovement jumps (CMJ), body composition, and heart rate variability (HRV) measures at rest before and after 4 weeks of preseason training. Athletes weekly stress symptoms were recorded by psychometric responses using the Daily Analysis of Life Demands for Athletes questionnaire and subjective ratings of well-being scale, respectively. The daily training load (arbitrary units) was assessed using the session of rating perceived exertion method. After the preseason training, there were no significant changes for body composition, SJ, CMJ, and RSAbest. The YoYo IR1, RSAmean, RSAworst, and RSAdecreament were significantly improved for both groups (p ? 0.05). The HRV parameters improved significantly within both groups (p ? 0.05) except for high frequency (HF, absolute and normalized units, [n.u.]), low frequency (LF) (n.u.), and the LF/HF ratio. A moderate effect size for the AddT group was observed for resting heart rate and several HRV measures. Training load and psychometric responses were similar between both groups. Additional RS training resulted in slightly greater positive changes for vagal-related HRV with similar improvements in performance and training stress during the preseason training in futsal players. PMID:24662230

  20. INFLUENCE OF NUMBER OF SETS ON BLOOD PRESSURE AND HEART RATE VARIABILITY AFTER A STRENGTH TRAINING SESSION.

    PubMed

    Figueiredo, Tiago; Rhea, Matthew R; Peterson, Mark; Miranda, Humberto; Bentes, Claudio M; Machado de Ribeiro Dos Reis, Victor Manuel; Simão, Roberto

    2014-11-26

    The purpose of this study was to compare the acute effects of one, three and five sets of strength training (ST), on heart rate variability (HRV) and blood pressure. Eleven male volunteers (age: 26.1 ± 3.6 years; body mass: 74.1 ± 8.1 kg; height: 172 ± 4 cm) with at least six months prior experience in ST participated in the study. After determining the one repetition-maximum load (1RM) for the bench press (BP), lat pull down (LPD), shoulder press (SP), biceps curl (BC), triceps extension (TE), leg press (LP), leg extension (LE) and leg curl (LC), the participants performed three different exercise sequences in a random order and 72 hours apart. During the first sequence, subjects performed a single set of 8-10 repetitions, at 70% 1RM, and with 2 minutes rest interval between exercises. Exercises were performed in the following order: BP, LPD, SP, BC, TE, LP, LE, and LC. During the second sequence, subjects performed the same exercise sequence, with the same intensity, two minutes rest interval between sets and exercises, but with three consecutive sets of each exercise. During the third sequence, the same protocol was followed but with five sets of each exercise. Before and after the training sessions, blood pressure and HRV were measured. The statistical analysis demonstrated a greater duration of post exercise hypotension following the 5-set program versus the 1-set or 3-sets (p<0.05). However, the 5-set program promoted a substantial cardiac stress, as demonstrated by HRV (p<0.05). These results indicate that 5-sets of 8 to 10 repetitions at 70% 1-RM load may provide the ideal stimulus for a post-exercise hypotensive response. Therefore, ST composed of upper and lower body exercises and performed with high volumes are capable of producing significant and extended post-exercise hypotensive response. In conclusion, strength and conditioning professionals can prescribe five sets per exercises if the goal is to reduce blood pressure after training. In addition, these findings may have importance, specifically in the early phase of high blood pressure development, but more research is needed in hypertensive populations to validate this hypothesis. PMID:25436620

  1. Design and dynamic simulation of a fixed pitch 56 kW wind turbine drive train with a continuously variable transmission

    NASA Technical Reports Server (NTRS)

    Gallo, C.; Kasuba, R.; Pintz, A.; Spring, J.

    1986-01-01

    The dynamic analysis of a horizontal axis fixed pitch wind turbine generator (WTG) rated at 56 kW is discussed. A mechanical Continuously Variable Transmission (CVT) was incorporated in the drive train to provide variable speed operation capability. One goal of the dynamic analysis was to determine if variable speed operation, by means of a mechanical CVT, is capable of capturing the transient power in the WTG/wind environment. Another goal was to determine the extent of power regulation possible with CVT operation.

  2. Influence of Acute Normobaric Hypoxia on Physiological Variables and Lactate Turn Point Determination in Trained Men

    PubMed Central

    Ofner, Michael; Wonisch, Manfred; Frei, Mario; Tschakert, Gerhard; Domej, Wolfgang; Kröpfl, Julia M.; Hofmann, Peter

    2014-01-01

    The goal of this study is to evaluate the response of physiological variables to acute normobaric hypoxia compared to normoxia and its influence on the lactate turn point determination according to the three-phase model of energy supply (Phase I: metabolically balanced at muscular level; Phase II: metabolically balanced at systemic level; Phase III: not metabolically balanced) during maximal incremental exercise. Ten physically active (VO2max 3.9 [0.49] l·min-1), healthy men (mean age [SD]: 25.3 [4.6] yrs.), participated in the study. All participants performed two maximal cycle ergometric exercise tests under normoxic as well as hypoxic conditions (FiO2 = 14%). Blood lactate concentration, heart rate, gas exchange data, and power output at maximum and the first and the second lactate turn point (LTP1, LTP2), the heart rate turn point (HRTP) and the first and the second ventilatory turn point (VETP1, VETP2) were determined. Since in normobaric hypoxia absolute power output (P) was reduced at all reference points (max: 314 / 274 W; LTP2: 218 / 184 W; LTP1: 110 / 96 W), as well as VO2max (max: 3.90 / 3.23 l·min-1; LTP2: 2.90 / 2.43 l·min-1; LTP1: 1.66 / 1.52 l·min-1), percentages of Pmax at LTP1, LTP2, HRTP and VETP1, VETP2 were almost identical for hypoxic as well as normoxic conditions. Heart rate was significantly reduced at Pmax in hypoxia (max: 190 / 185 bpm), but no significant differences were found at submaximal control points. Blood lactate concentration was not different at maximum, and all reference points in both conditions. Respiratory exchange ratio (RER) (max: 1.28 / 1.08; LTP2: 1.13 / 0.98) and ventilatory equivalents for O2 (max: 43.4 / 34.0; LTP2: 32.1 / 25.4) and CO2 (max: 34.1 / 31.6; LTP2: 29.1 / 26.1) were significantly higher at some reference points in hypoxia. Significant correlations were found between LTP1 and VETP1 (r = 0.778; p < 0.01), LTP2 and HRTP (r = 0.828; p < 0.01) and VETP2 (r = 0.948; p < 0.01) for power output for both conditions. We conclude that the lactate turn point determination according to the three-phase-model of energy supply is valid in normobaric, normoxic as well as hypoxic conditions. The turn points for La, HR, and VE were reproducible among both conditions, but shifted left to lower workloads. The lactate turn point determination may therefore be used for the prescription of exercise performance in both environments. Key Points The lactate turn point concept can be used for performance testing in normoxic and hypoxic conditions The better the performance of the athletes the higher is the effect of hypoxia The HRTP and LTP2 are strongly correlated that allows a simple performance testing using heart rate measures only. PMID:25435769

  3. Pressure regulating valve controller

    SciTech Connect

    Goodman, R.B.

    1988-04-05

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

  4. Sliding-gate valve

    DOEpatents

    Usnick, George B. (Birmingham, AL); Ward, Gene T. (Sylacauga, AL); Blair, Henry O. (Sylacauga, AL); Roberts, James W. (Charlotte, NC); Warner, Terry N. (Wilsonville, AL)

    1979-01-01

    This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

  5. Valve body for oilfield applications

    SciTech Connect

    Bailey, T.F.; Campbell, J.E.

    1992-01-21

    This patent describes a valve to pump fluids, save valve sealingly cooperating with a valve set having a throughbore. It comprises a valve head having an axial cavity with an interior annular side wall; a valve body attached to the valve head, the valve body including an axial neck portion received within the cavity of the valve head and having an outer annular surface corresponding to the interior annular side wall of the cavity; and means to lockingly attach the valve body to the valve head, the valve head being made of a metal material and the valve body being made of an elastomer material, the locking means including at least one annular tongue formed on the outer annular surface of the neck portion of the valve body, the at least one tongue having a frusto-conical upper surface, a cylindrical intermediate surface and a curved lower surface the at least one annular tongue lockingly engaging at least one corresponding annular groove formed in the interior annular side wall of the internal cavity of the valve head thereby preventing inadvertent withdrawal of the neck portion from the cavity and separation of the valve body from the valve head.

  6. Face-Sealing Butterfly Valve

    NASA Technical Reports Server (NTRS)

    Tervo, John N.

    1992-01-01

    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.

  7. Transcatheter CoreValve valve-in-valve implantation in a stentless porcine aortic valve for severe aortic regurgitation

    PubMed Central

    Yong, Celina M; Buchbinder, Maurice; Giacomini, John C

    2014-01-01

    Key Clinical Message We describe the first valve-in-valve Corevalve transcatheter aortic valve replacement in the St. Jude Toronto stentless porcine aortic valve in the United States, which enabled this 59-year-old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction. PMID:25548631

  8. Engineering the Heart: Heart Valves

    NSDL National Science Digital Library

    2014-09-18

    Students learn how healthy human heart valves function and the different diseases that can affect heart valves. They also learn about devices and procedures that biomedical engineers have designed to help people with damaged or diseased heart valves. Students learn about the pros and cons of different materials and how doctors choose which engineered artificial heart valves are appropriate for certain people.

  9. Prosthetic valve endocarditis. A survey

    Microsoft Academic Search

    M Ben Ismail; N Hannachi; F Abid; Z Kaabar; J F Rougé

    1987-01-01

    Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in

  10. Cavitation Inception in Spool Valves

    Microsoft Academic Search

    C. Samuel Martin; H. Medlarz; D. C. Wiggert; C. Brennen

    1981-01-01

    Cavitation has been investigated in directional control valves in order to identify damage mechanisms characteristic of components of aircraft hydraulic systems. Tests have been conducted in a representative metal spool valve and in a model three times larger. Data taken under noncavitating conditions with both valves showed that the position of the high-velocity annular jet shifts orientation, depending upon valve

  11. The effect of a complex training and detraining programme on selected strength and power variables in early pubertal boys

    Microsoft Academic Search

    Lee Ingle; Mike Sleap; Keith Tolfrey

    2006-01-01

    Complex training, a combination of resistance training and plyometrics is growing in popularity, despite limited support for its efficacy. In pre- and early pubertal children, the study of complex training has been limited, and to our knowledge an examination of its effect on anaerobic performance characteristics of the upper and lower body has not been undertaken. Furthermore, the effect of

  12. Long life valve design concepts

    NASA Technical Reports Server (NTRS)

    Jones, J. R.; Hall, A. H., Jr.

    1975-01-01

    Valve concept evaluation, final candidate selection, design, manufacture, and demonstration testing of a pneumatically actuated 10-inch hybrid poppet butterfly shutoff valve are presented. Conclusions and recommendations regarding those valve characteristics and features which would serve to guide in the formulation of future valve procurements are discussed. The pertinent design goals were temperature range of plus 200 to minus 423 F, valve inlet pressure 35 psia, actuation pressure 750 psia, main seal leakage 3 x 0.00001 sccs at 35 psia valve inlet pressure, and a storage and operating life of 10 years. The valve was designed to be compatible with RP-1, propane, LH2, LO2, He, and N2.

  13. Mesofluidic two stage digital valve

    DOEpatents

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

    2013-12-31

    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.

  14. Improve safety with pilot operated relief valves

    SciTech Connect

    Emerson, G. [Anderson, Greenwood and Co., Stafford, TX (United States)

    1996-10-01

    A weakness inherent in balanced bellows pressure relief valves (PRVs) that can cause premature failure can be avoided by using pilot operated PRVs as an alternative. Now better able to handle adverse service conditions, pilot operated PRVs are suitable for a wide range of gas, liquid and mixed-phase services. Traditionally, however, balanced bellows PRVs have been applied as overpressure protection for three notable reasons: a constant PRV set pressure with the presence of variable, superimposed back pressure (at the PRV outlet prior to its opening); valve stability and adequate capacity when built-up back pressure (at the PRV outlet during its relief cycle) exceeds 10%; and spring and guided parts barriered from the process fluid. With these benefits in mind, balanced bellows PRVs have been generally adapted by many hydrocarbon processing companies that have experienced costly, and often dangerous, premature bellows failures. Corrosion, valve instability and/or bellows flutter are causes of these failures.

  15. Mitral Valve Prolapse.

    ERIC Educational Resources Information Center

    Bergy, Gordon G.

    1980-01-01

    Mitral valve prolapse is the most common heart disease seen in college and university health services. It underlies most arrhythmia and many chest complaints. Activity and exercise restrictions are usually unnecessary. (Author/CJ)

  16. Mitral Valve Repair Surgery

    MedlinePLUS

    ... the slide which demonstrates what he has just told you, in terms of placing these sutures, in this ... right before we began the mitral valve work, you were told that we excised the left atrial appendage. Why ...

  17. Micro regulating ball valve

    NASA Technical Reports Server (NTRS)

    Hawkins, J. W.

    1972-01-01

    Ball valve of simple, rugged configuration overcomes leakage because there are no critical wear areas. Design has stable and precise calibration. Device can be assembled or disassembled in seconds and needs no lubrication.

  18. Mitral valve regurgitation

    MedlinePLUS

    ... be done to look at the heart valve structure and function: CT scan of the chest Echocardiogram (an ultrasound examination of the heart) - transthoracic or transesophageal Magnetic resonance imaging (MRI) Cardiac catheterization may be done if ...

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

    PubMed

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

    2013-11-01

    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. PMID:23864579

  20. Valve for gas centrifuges

    DOEpatents

    Hahs, Charles A. (Oak Ridge, TN); Burbage, Charles H. (Oak Ridge, TN)

    1984-01-01

    The invention is a pneumatically operated valve assembly for simultaneously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two of the lines so closed. The valve assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

  1. Liquid blocking check valve

    DOEpatents

    Merrill, John T. (Pleasant Hill, CA)

    1984-01-01

    A liquid blocking check valve useful particularly in a pneumatic system utilizing a pressurized liquid fill chamber. The valve includes a floatable ball disposed within a housing defining a chamber. The housing is provided with an inlet aperture disposed in the top of said chamber, and an outlet aperture disposed in the bottom of said chamber in an offset relation to said inlet aperture and in communication with a cutaway side wall section of said housing.

  2. Valve malfunction detection apparatus

    NASA Technical Reports Server (NTRS)

    Burley, Richard K. (inventor)

    1993-01-01

    A detection system is provided for sensing a malfunction of a valve having an outlet connected to an end of a first pipe through which pressurized fluid may be flowed in a downstream direction away from the valve. The system includes a bypass pipe connected at its opposite ends to the first pipe and operative to bypass a portion of the fluid flow therethrough around a predetermined section thereof. A housing is interiorly divided by a flexible diaphragm into first and second opposite chambers which are respectively communicated with the first pipe section and the bypass pipe, the diaphragm being spring-biased toward the second chamber. The diaphragm housing cooperates with check valves and orifices connected in the two pipes to create and maintain a negative pressure in the first pipe section in response to closure of the valve during pressurized flow through the first pipe. A pressure switch senses the negative pressure and transmits a signal indicative thereof to a computer. Upon cessation of the signal while the valve is still closed, the computer responsively generates a signal indicating that the valve, or another portion of the detection system, is leaking.

  3. [Transcatheter aortic valve replacement].

    PubMed

    Sawa, Yoshiki

    2014-07-01

    While transcatheter aortic valve replacement( TAVR) has spread rapidly all over the world for highrisk patients with severe aortic stenosis (AS), SAPIEN XT was approved in Japan in October 2013. Since that, approximately 400 TAVR cases were performed in Japan. In our institute, we have performed 164 cases since first case in Japan in 2009 and have achieved satisfactory early results(30-day mortality:1.2%). At the same time, however, simultaneously various TAVR-related complications including a paravalvular leak, stroke, vascular complications, and coronary obstruction were observed. A reduction in the incidence and severity of these complications had led technical improvements in various new devices(2nd generation TAVR device such as the SAPIEN 3, ACURATE, and JenaValve) and in implantation techniques including repositioning/recapturing features, paravalvular sealing technologies, and prevention of coronary obstruction. Furthermore, there is also increasing experience with special indications for TAVR such as pure aortic valve insufficiency or valve-in-valve techniques. Currently, an increasing number of publications of midterm results demonstrate good prosthetic valve function and durability, with good quality of life and low morbidity after TAVR. There are also some randomized trials such as PARTNER 2 or SURTAVI to investigate potential benefits of TAVR for intermediate-risk patients. These improvements in the TAVR devices promises the expansion of TAVR towards the treatment of lower-risk patients in the near future. PMID:25138938

  4. Self closing equalizing valve for a subsurface well safety valve

    SciTech Connect

    Pringle, R.E.

    1988-02-02

    A subsurface well safety valve for controlling the fluid flow through a well conduit is described comprising, a housing having a bore and a first valve closure member in the bore moving between open and closed positions for controlling fluid flow through the bore, a tubular member telescopically movable in the housing for controlling the movement of the first valve closure member, biasing means for moving the tubular member in a direction to close the valve, a first piston and cylinder assembly in the housing contacting and moving the tubular member, a fluid control passageway positioned in the housing in communication with the first piston and cylinder assembly and adapted to be in communication with fluid pressure at the well surface, a valve seat and valve element positioned in the fluid control passageway and positioned to shut off flow from the fluid passageway to the first piston and cylinder assembly when the first valve closure member is opened, an equalizing line in communication with the bore of the housing between points below and above the first valve closure member, an equalizing valve in the equalizing line, a second piston and cylinder assembly in the housing connected to the equalizing valve, the second piston and cylinder assembly being in fluid communication with the fluid control passageway through a fluid communication line downstream of the valve seat and element for opening the equalizing valve prior to the opening of the first valve, second biasing means for moving the equalizing valve to a closed position, and a fluid bypass for bypassing the second piston and cylinder assembly for bleeding off opening pressure to the equalizing valve after the valve seat has seated on the valve element to allow the second biasing means to close the equalizing valve.

  5. Differential pressure energized circulating valve

    SciTech Connect

    O'Brien, T. B.; Thomas, E. W.

    1984-11-13

    A circulating valve is provided for connection into the tubing string of a well for establishing selective flow of fluid between the tubing string and the well casing. The circulating valve incorporates a valve body which is adapted for connection into the tubing string of the well, which body defines a flow passage in registry with the flow passage of the tubing string. A valve seat is provided on the valve body and an outlet opening is defined downstream of the valve seat which is of sufficiently restricted dimension to permit opening of the valve at a particular injection pressure and to permit maintenance of the valve open condition by means of a pressure lower than the valve opening injection pressure.

  6. Short and long-term effects of a single bout of exercise on heart rate variability: comparison between constant and interval training exercises

    Microsoft Academic Search

    Laurent Mourot; Malika Bouhaddi; Nicolas Tordi; Jean-Denis Rouillon; Jacques Regnard

    2004-01-01

    Heart rate variability (HRV) was assessed during the short- (within 1 h) and long- (within 48 h) term recovery following a single bout of either constant (CST) or interval training (SWEET) exercise performed at the same total physical work [9.4 (0.3) kJ kg ?1]. R-R intervals, systolic (SAP) and diastolic (DAP) arterial pressures were recorded in supine and upright positions before and 1, 24

  7. CFD Analysis of a Novel High Speed Rotary On/Off Valve 283 Proc. of 6th

    E-print Network

    Li, Perry Y.

    systems are either inefficient (using throttling valves) or expensive and bulky (variable displacement) fast transition to reduce the time when the valve is partially open, 3) ability to operate at high PWMCFD Analysis of a Novel High Speed Rotary On/Off Valve 283 Proc. of 6th FPNI-PhD Symp. West

  8. 9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY IN 1931, 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  9. Pressure valve for needle gate valve control. June 13, 1913. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Pressure valve for needle gate valve control. June 13, 1913. Photocopy of original drawing. Drawing on file at the Salt River Project Archives. Phoenix, Arizona - Cross Cut Hydro Plant, North Side of Salt River, Tempe, Maricopa County, AZ

  10. Inverse differential casing cementing float valve

    SciTech Connect

    Kuhlman, R.D. Jr.

    1986-10-07

    This patent describes an inverse differential fill-up casing cementing float valve having an inlet thereto and outlet therefrom characterized in that the float valve permits fluid flow therethrough in a first direction upon a predetermined fluid pressure level thereacross and continuously prevents fluid flow therethrough in a second direction. The float valve includes: an annular float valve housing; a back pressure valve assembly contained within the annular float valve housing; a first differential pressure check valve assembly connected to the back pressure valve assembly and contained within the annular float valve housing; a second differential pressure check valve assembly connected to the first differential pressure check valve assembly and contained within the annular float valve housing; and cementitious filter material retaining and securing the back pressure valve assembly, the first differential pressure check valve assembly and the second differential pressure check valve assembly within the annular float valve housing.

  11. Check valves aging assessment

    SciTech Connect

    Haynes, H.D.

    1991-01-01

    In support of the NRC Nuclear Plant Aging Research (NPAR) program, the Oak Ridge National Laboratory (ORNL) has carried out an assessment of several check value diagnostic monitoring methods, in particular, those based on measurements of acoustic emission, ultrasonics, and magnetic flux. The evaluations have focussed on the capabilities of each method to provide information useful in determining check valve aging and service wear effects, check valve failures, and undesirable operating modes. This paper describes the benefits and limitations associated with each method and includes recent laboratory and field test data, including data obtained from the vendors who recently participated in a comprehensive series of tests directed by a nuclear industry users group. In addition, as part of the ORNL Advanced Diagnostic Engineering Research and Development Center (ADEC), two novel nonintrusive monitoring methods were developed that provide several unique capabilities. These methods, based on external ac- an dc-magnetic monitoring are also described. None of the examined methods could, by themselves, monitor both the instantaneous position and motion of check valve internals and valve leakage; however, the combination of acoustic emission monitoring with one of the other methods provides the means to determine vital check valve operational information.

  12. Sutureless aortic valve replacement

    PubMed Central

    Phan, Kevin

    2015-01-01

    The increasing incidence of aortic stenosis and greater co-morbidities and risk profiles of the contemporary patient population has driven the development of minimally invasive aortic valve surgery and percutaneous transcatheter aortic valve implantation (TAVI) techniques to reduce surgical trauma. Recent technological developments have led to an alternative minimally invasive option which avoids the placement and tying of sutures, known as “sutureless” or rapid deployment aortic valves. Potential advantages for sutureless aortic prostheses include reducing cross-clamp and cardiopulmonary bypass (CPB) duration, facilitating minimally invasive surgery and complex cardiac interventions, whilst maintaining satisfactory hemodynamic outcomes and low paravalvular leak rates. However, given its recent developments, the majority of evidence regarding sutureless aortic valve replacement (SU-AVR) is limited to observational studies and there is a paucity of adequately-powered randomized studies. Recently, the International Valvular Surgery Study Group (IVSSG) has formulated to conduct the Sutureless Projects, set to be the largest international collaborative group to investigate this technology. This keynote lecture will overview the use, the potential advantages, the caveats, and current evidence of sutureless and rapid deployment aortic valve replacement (AVR).

  13. Fast closing valve

    DOEpatents

    Hanson, Clark L. (Livermore, CA)

    1984-01-10

    A valve is provided for protecting the high vacuum of a particle accelera in the event of air leakage, wherein the valve provides an axially symmetrical passage to avoid disturbance of the partical beam during normal operation, and yet enables very rapid and tight closure of the beam-carrying pipe in the event of air leakage. The valve includes a ball member (30) which can rotate between a first position wherein a bore (32) in the member is aligned with the beam pipe, and a second position out of line with the pipe. A seal member (38) is flexibly sealed to the pipe, and has a seal end which can move tightly against the ball member after the bore has rotated out of line with the pipe, to thereby assure that the seal member does not retard rapid rotation of the ball valve member. The ball valve member can be rapidly rotated by a conductive arm (40) fixed to it and which is rotated by the discharge of a capacitor bank through coils (44, 45) located adjacent to the arm.

  14. Heart valve replacement: Which valve for which patient?

    Microsoft Academic Search

    Joseph Huh; Faisal Bakaeen

    2006-01-01

    The ideal heart valve substitute would show no deterioration or thrombogenicity, offer no resistance to blood flow, and be\\u000a easy to implant. However, such a valve does not exist and we must accept compromises in some of these qualities based on our\\u000a patients' needs. In selection of cardiac valve prosthesis, valve-related factors such as durability, thrombogenicity, and\\u000a fluid dynamics should

  15. Computerized valve packing program

    SciTech Connect

    Taraszki, R. [Argo Packing Co., Aurora, IL (United States)

    1996-11-01

    The purpose of this paper is to present the advantages of a computerized valve packing program and demonstrate Valveman{trademark}, a windows based, completely automated valve packing program. With deregulation of the power industry, it is evident to be more competitive, utilities are decreasing maintenance staffs. This challenges the personnel to be more productive. One area that is usually duplicated by various groups on a site is valve packing. So it is evident that a way of simplifying this process is very beneficial, not only from an efficiency stand point but also to a greater consistency and higher quality level. By establishing a consistency, it is easier to change personnel with a minimum learning curve. Also, the administration can get a complete picture of each job for better evaluation or to measure performance.

  16. Well valve control system

    SciTech Connect

    Schwendemann, K.L.; McCracken, O.W.; Mondon, C.G.; Wortham, L.C.

    1987-01-13

    A system is described for controlling well testing through an upper and lower test string with a subsea test tree connected therebetween and latch means to release the upper test string from the subsea test tree comprising: a. first and second selectively programmable microprocessor means; b. means for storing system operating limits in each microprocessor means; c. means for changing the operating limits in response to changes in well conditions; d. means for communicating operating fluid pressure to the subsurface test tree and the latch means; e. solenoid pilot valves controlling the flow of the operating fluid pressure to the subsea test tree and the latch means; f. the first microprocessor means located at a central control console; g. the second microprocessor means located near the solenoid valves; h. means for transmitting signals between the first and second microprocessor means and validating the accuracy of the signals; and i. electronic circuits to control operation of the solenoid valves in response to validated signals.

  17. Josephson magnetic rotary valve

    NASA Astrophysics Data System (ADS)

    Soloviev, I. I.; Klenov, N. V.; Bakurskiy, S. V.; Bol'ginov, V. V.; Ryazanov, V. V.; Kupriyanov, M. Yu.; Golubov, A. A.

    2014-12-01

    We propose a control element for a Josephson spin valve. It is a complex Josephson device containing ferromagnetic (F) layer in the weak-link area consisting of two regions, representing 0 and ? Josephson junctions, respectively. The valve's state is defined by mutual orientations of the F-layer magnetization vector and boundary line between 0 and ? sections of the device. We consider possible implementation of the control element by introduction of a thin normal metal layer in a part of the device area. By means of theoretical simulations, we study properties of the valve's structure as well as its operation, revealing such advantages as simplicity of control, high characteristic frequency, and good legibility of the basic states.

  18. Hydrogen gas relief valve

    DOEpatents

    Whittlesey, Curtis C. (Birmingham, MI)

    1985-01-01

    An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

  19. Magnetostrictive valve assembly

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2008-01-01

    A magnetostrictive valve assembly includes a housing that defines a passage with a seat being formed therein. A magnetically-biased and axially-compressed magnetostrictive assembly slidingly fitted in the passage is configured as a hollow and open-ended conduit adapted to support a flow of a fluid therethrough. Current-carrying coil(s) disposed about the passage in the region of the magnetostrictive assembly generate a magnetic field in the passage when current flows through the coil(s). A hollow valve body with side ports is coupled on one end thereof to an axial end of the magnetostrictive assembly. The other end of the valve body is designed to seal with the seat formed in the housing's passage when brought into contact therewith.

  20. Valve-spring Surge

    NASA Technical Reports Server (NTRS)

    Marti, Willy

    1937-01-01

    Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

  1. Locking apparatus for gate valves

    DOEpatents

    Fabyan, Joseph (Livermore, CA); Williams, Carl W. (Manteca, CA)

    1988-01-01

    A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing futher movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

  2. Variable speed drives

    Microsoft Academic Search

    Spitzer

    1990-01-01

    Variable speed drives present many possibilities for real operating economy and production improvement. This book presents the electrical, hydraulic, chemical, and instrumental information necessary for sound judgment of the technology. Application of control valves and other final control elements are compared and contrasted with variable frequency and variable speed drive replacements. Prime utility costs and plant utilities are discussed, along

  3. Tide gate valve

    SciTech Connect

    Raftis, S. G.

    1985-01-08

    A tide gate check valve in which at least three converging sides are provided at a tapered region of a flexible sleeve, so that on reverse back pressure build-up of fluid, reverse fluid flow is prevented, while the valve sleeve does not invert or collapse. The present configuration features embedded reinforcing elements for resisting inversion or collapsing when the back pressure builds up. This feature is especially important for large-sized conduits of 36'' or 72'' diameter, or even larger, such as are common in storm sewer applications.

  4. Aging Heart Valves

    NSDL National Science Digital Library

    2014-09-18

    In this unit, students learn about the form and function of the human heart through lecture, research and dissection. Following the steps of the Legacy Cycle, students brainstorm, research, design and present viable solutions to various heart conditions as presented through a unit challenge. Additionally, students study how heart valves work and investigate how faulty valves can be replaced with new ones through advancements in engineering and technology. This unit demonstrates to students how and why the heart is such a powerful organ in our bodies

  5. Automatic monitoring of valve status

    SciTech Connect

    Prinz, F.B.; Chern, J.H.

    1989-06-01

    Authors propose establishing the relationship between valve leaking and thermal gradient to allow detection of valve leakage by observing the piping system`s temperature profile and using an expert system to infer the valve condition. They describe their work toward this and their January 1988 report thereon. The authors also suggest designing modem power plants to accommodate a remotely controlled or autonomous vehicle which would carry a device for thermal-gradient leak detection to examine valves in situ.

  6. Well safety and kill valve

    SciTech Connect

    Deaton, T.M.

    1986-12-30

    A valve device is described for use in tubing above a packer set in casing above a well formation comprising: (a) a housing connectable in well tubing and having a longitudinal flow passage therethrough and a flow passage through the housing wall intersecting the longitudinal flow passage; (b) lower ball valve means controlling flow through the longitudinal flow passage; (c) upper sleeve valve means controlling flow through the housing wall flow passages between the valve device exterior and the longitudinal flow passage. The valve means is cooperable such that when the upper valve means is in closed position, the lower valve means is in open position, and when the upper valve means is in open position, the lower valve means is in closed position; (d) locking means for holding the valve means at one position and releasing the valve means for movement to another position; (e) pressure responsive means for releasing the locking means; and (f) operator means for operating the valve means between positions including an operator tube having a shoulder thereon, mounted for longitudinal movement in the housing, an internal shoulder in the housing and a spring disposed around the operator tube between the housing and operator tube shoulders, biasing the operator tube upwardly.

  7. Valve stem and packing assembly

    DOEpatents

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    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.

  8. Valve stem and packing assembly

    DOEpatents

    Wordin, J.J.

    1991-09-03

    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.

  9. Improved bellows sealed plug valve

    SciTech Connect

    Dukas, S.J. Jr.

    1989-10-29

    It is an object of the present invention to provide a bellows sealed 1/4 turn valve wherein means are provided for translating linear motion to rotational motion between the bellows seal and the valve body. This paper details the features of the valve. 6 figs.

  10. Lightweight Valve Closes Duct Quickly

    NASA Technical Reports Server (NTRS)

    Fournier, Walter L.; Burgy, N. Frank

    1991-01-01

    Expanding balloon serves as lightweight emergency valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet valve capable of closing duct of equal diameter.

  11. Pilot-booster control valve

    NASA Technical Reports Server (NTRS)

    Marley, D.

    1970-01-01

    Two-stage, pressure-sensing control valve is designed for servocontrol of 10-inch main tank valve regulating pressure of liquid oxygen in tank and serving to vent tank during filling. Valve uses a negative-rate Belleville spring to cancel positive spring rates of bellows and coil springs.

  12. Risks for Heart Valve Problems

    MedlinePLUS

    ... increase a persons’ risk for sudden death or cause rapid development of problems in and around the heart that can become fatal without treatment. People who have been diagnosed with a heart murmur , a defect like a bicuspid aortic valve, mitral valve prolapse or a mild form of valve disease should ...

  13. Self-compassion training modulates alpha-amylase, heart rate variability, and subjective responses to social evaluative threat in women

    PubMed Central

    Arch, Joanna J.; Brown, Kirk Warren; Dean, Derek J.; Landy, Lauren N.; Brown, Kimberley; Laudenslager, Mark L.

    2014-01-01

    A growing body of research has revealed that social evaluative stressors trigger biological and psychological responses that in chronic forms have been linked to aging and disease. Recent research suggests that self-compassion may protect the self from typical defensive responses to evaluation. We investigated whether brief training in self-compassion moderated biopsychological responses to the Trier Social Stress Test (TSST) in women. Compared to attention (placebo) and no-training control conditions, brief self-compassion training diminished sympathetic (salivary alpha-amylase), cardiac parasympathetic, and subjective anxiety responses, though not HPA-axis (salivary cortisol) responses to the TSST. Self-compassion training also led to greater self-compassion under threat relative to the control groups. In that social stress pervades modern life, self-compassion represents a promising approach to diminishing its potentially negative psychological and biological effects. PMID:24636501

  14. Self-compassion training modulates alpha-amylase, heart rate variability, and subjective responses to social evaluative threat in women.

    PubMed

    Arch, Joanna J; Brown, Kirk Warren; Dean, Derek J; Landy, Lauren N; Brown, Kimberley D; Laudenslager, Mark L

    2014-04-01

    A growing body of research has revealed that social evaluative stressors trigger biological and psychological responses that in chronic forms have been linked to aging and disease. Recent research suggests that self-compassion may protect the self from typical defensive responses to evaluation. We investigated whether brief training in self-compassion moderated biopsychological responses to the Trier Social Stress Test (TSST) in women. Compared to attention (placebo) and no-training control conditions, brief self-compassion training diminished sympathetic (salivary alpha-amylase), cardiac parasympathetic, and subjective anxiety responses, though not HPA-axis (salivary cortisol) responses to the TSST. Self-compassion training also led to greater self-compassion under threat relative to the control groups. In that social stress pervades modern life, self-compassion represents a promising approach to diminishing its potentially negative psychological and biological effects. PMID:24636501

  15. Valve thrombosis 7 months after transcatheter aortic valve implantation.

    PubMed

    Pingpoh, Clarence; Pache, Gregor; Nawras, Diab; Guenkel, Ludwig; Sami, Kueri; Zeh, Wolfgang; Zimmer, Emmanuel; Jander, Nikolaus; Siepe, Matthias; Beyersdorf, Friedhelm

    2014-09-01

    A 77-year old man underwent transcatheter aortic valve implantation for severe aortic stenosis with a 29-mm Edwards-Sapien XT aortic valve bioprosthesis. Periprocedural transesophageal echocardiography and computed tomography showed good positioning and expansion of the prosthesis with only minor transvalvular insufficiency. On a routine checkup 7 months later, echocardiography and computed tomography showed a high transvalvular gradient suggestive of valve thrombosis, which could not be treated with warfarin. Because of rapid deterioration of the patient's clinical condition, an urgent surgical valve replacement was performed 4 weeks after initial notice of the valve thrombosis. The patient's postoperative stay was uneventful. PMID:25193189

  16. Design and sizing of electromagnetic linear actuators for valve applications

    E-print Network

    Paris-Sud XI, Université de

    , a description of the design and sizing of variable reluctance or permanent magnet devices is given. The mainPage 1/9 Design and sizing of electromagnetic linear actuators for valve applications J.C Vannier1 qualities of each structure are enhanced. Keywords: Linear motion actuator, variable reluctance, permanent

  17. Transcatheter aortic valve-in-valve implantation of a CoreValve in a degenerated stenotic Sapien heart valve prosthesis.

    PubMed

    Hoffmann, Rainer; Möllmann, Helge; Lotfi, Shahram

    2013-12-01

    Treatment options for re-stenotic aortic valve prosthesis implanted by transcatheter technique have not been evaluated systematically. We describe the case of a 75-year-old dialysis patient who was treated by transcatheter aortic valve implantation 3.5 years ago and now presented with severe stenosis of the percutaneous heart valve. The patient was initially treated with a trans-apical implantation of an Edwards Sapien 26 mm balloon expandable valve. The patient remained asymptomatic for 3 years when he presented with increasing shortness of breath and significant calcification of the valve prosthesis on transesophageal echocardiography. Valve-in-valve percutaneous heart valve implantation using a 26-mm CoreValve prosthesis was performed under local anesthesia. The prosthesis was implanted without prior valvuloplasty. Pacing with a frequency of 140/min was applied during placement of the valve prosthesis. Positioning was done with great care using only fluoroscopic guidance with the aim to have the ventricular strut end of the CoreValve prosthesis 5 mm higher than the ventricular strut end of the Edwards Sapien prosthesis. After placement of the CoreValve prosthesis within the Edwards Sapien valve additional valvuloplasty with rapid pacing was performed in order to further expand the CoreValve prosthesis. The final result was associated with a remaining mean gradient of 5 mm Hg and no aortic regurgitation. In conclusion, implantation of a CoreValve prosthesis for treatment of a restenotic Edwards Sapien prosthesis is feasible and is associated with a good functional result. PMID:22707435

  18. Thermostatic Radiator Valve Evaluation

    SciTech Connect

    Dentz, Jordan [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States); Ansanelli, Eric [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States)

    2015-01-01

    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.

  19. Model Heart Valves

    NSDL National Science Digital Library

    2014-09-18

    Students use provided materials to design and build prototype artificial heart valves. Their functioning is demonstrated using water to simulate the flow of blood through the heart. Upon completion, teams demonstrate their fully functional prototypes to the rest of the class, along with a pamphlet that describes the device and how it works.

  20. Valve for gas centrifuges

    DOEpatents

    Hahs, C.A.; Rurbage, C.H.

    1982-03-17

    The invention is pneumatically operated valve assembly for simulatenously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two on the lines so closed. The value assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

  1. Compensated throttle valve

    Microsoft Academic Search

    1986-01-01

    An improvement in automatic transmission controls is described for use with motor vehicles having cyclic engine loads caused by electically activated accessory operation, and wherein the transmission has a throttle pressure regulator valve responsive to the vehicle throttle position to generate a pressure signal used by the transmission control to in part determine at least a ratio change shift points.

  2. Fuel pressure regulator valve

    Microsoft Academic Search

    Hornby

    1990-01-01

    This patent describes a fuel pressure regulator valve. It comprises: a housing containing a diaphragm assembly that divides the housing into two chambers, one chamber being a fuel chamber, and the other chamber being a control chamber, the fuel chamber having an inlet adapted to be communicated to a supply of pressurized fluid whose pressure is to be regulated and

  3. Pressure regulating valve

    Microsoft Academic Search

    Hayashi

    1988-01-01

    This patent describes a pressure regulating valve for regulating a pressure of fuel to be supplied to a fuel injection device, comprising: a diaphragm chamber having a connecting portion for inducing an intake manifold vacuum in the vicinity of a nozzle hold of the fuel injection device; a fuel chamber having a connecting portion for inducing a fuel and located

  4. Float valve control

    SciTech Connect

    Tchitdjian, J.K.

    1986-08-12

    This patent describes a liquid level control device for monitoring the level of water in a steam generating tank between predetermined upper, intermediate and lower levels, the tank equipped with a valve for introducing water into the tank and valve means for introducing heat energy to the water to generate steam. The device consists of: (a) a glass gauge tube adapted to be vertically mounted exteriorally of the tank; (b) a top and bottom cover covering the ends of the glass gauge tube, the bottom cover including an opening for communicating with the liquid in the tank and the top cover including an opening for communicating with the steam generated in the tank; (c) upper and lower magnetic float means mounted co-axially within the glass guage tube; (d) the upper magnetic float means including means to activate the water valve when the water is in the region of the predetermined intermediate level so as to introduce water into the tank until the water is in the region of the predetermined upper level, and to deactivate the water valve and stop the introduction of water into the tank when the water is in the region of the predetermined upper level; (e) the lower magnetic float means is adapted to continuously maintain the application of heat energy during the introduction of water at the intermediate level, and the lower magnetic float means is adapted to activate the heat energy valve means to stop the application of heat energy in the steam generating tank when the water is in the region of the predetermined lower level.

  5. Well reverse flow check valve

    SciTech Connect

    Pringle, R.E.; Morris, A.J.

    1987-08-25

    A well reverse flow check valve is described for use in a well tubing comprising, a housing having a bore and adapted to be placed in a well production tubing above an electrical submersible pump, flapper valve element in the bore moving between open and closed positions for allowing upward flow through the bore but preventing downward flow through the bore, a flow tube telescopically movable in the housing upwardly for opening the flapper valve element, and downwardly for actuating the closing of the flapper valve element, means connected to the flow tube for biasing the flow tube downwardly for closing the flapper valve element, pressure responsive means connected to the flow tube for moving the flow tube upwardly in response to an upward flow rate pressure drop for opening the flapper valve element open, the housing having a port between the bore and the outside of the housing, valve closure means releasably connected to the housing and initially blocking the port, the pressure responsive means is an expandable and contractible restriction connected to the flow tube and extending into the bore, the port in uncovered when the valve closure means is moved downwardly, and the valve closure means includes the flapper valve element and a valve seat connected to a support which is releasably connected to the housing.

  6. Multi-port valve assembly

    DOEpatents

    Guggenheim, S. Frederic (Teaneck, NJ)

    1986-01-01

    A multi-port fluid valve apparatus is used to control the flow of fluids through a plurality of valves and includes a web, which preferably is a stainless steel endless belt. The belt has an aperture therethrough and is progressed, under motor drive and control, so that its aperture is moved from one valve mechanism to another. Each of the valve mechanisms comprises a pair of valve blocks which are held in fluid-tight relationship against the belt. Each valve block consists of a block having a bore through which the fluid flows, a first seal surrounding the bore and a second seal surrounding the first seal, with the distance between the first and second seals being greater than the size of the belt aperture. In order to open a valve, the motor progresses the belt aperture to where it is aligned with the two bores of a pair of valve blocks, such alignment permitting a flow of the fluid through the valve. The valve is closed by movement of the belt aperture and its replacement, within the pair of valve blocks, by a solid portion of the belt.

  7. Mathematical modeling of aortic valve dynamics during systole.

    PubMed

    Aboelkassem, Yasser; Savic, Dragana; Campbell, Stuart G

    2015-01-21

    We have derived a mathematical model describing aortic valve dynamics and blood flow during systole. The model presents a realistic coupling between aortic valve dynamics, sinus vortex local pressure, and variations in the systemic vascular resistance. The coupling is introduced by using Hill?s classical semi-spherical vortex model and an aortic pressure-area compliance constitutive relationship. The effects of introducing aortic sinus eddy vortices and variable systemic vascular resistance on overall valve opening-closing dynamics, left ventricular pressure, aortic pressure, blood flow rate, and aortic orifice area are examined. In addition, the strength of the sinus vortex is coupled explicitly to the valve opening angle, and implicitly to the aortic orifice area in order to predict how vortex strength varies during the four descriptive phases of aortic valve motion (fast-opening, fully-opening, slow-closing, and fast-closing). Our results compare favorably with experimental observations and the model reproduces well-known phenomena corresponding to aortic valve function such as the dicrotic notch and retrograde flow at end systole. By invoking a more complete set of physical phenomena, this new model will enable representation of pathophysiological conditions such as aortic valve stenosis or insufficiency, making it possible to predict their integrated effects on cardiac load and systemic hemodynamics. PMID:25451522

  8. In the era of the valve-in-valve: is transcatheter aortic valve implantation (TAVI) in sutureless valves feasible?

    PubMed Central

    Saia, Francesco; Pellicciari, Giovanni; Phan, Kevin; Ferlito, Marinella; Dall’Ara, Gianni; Di Bartolomeo, Roberto; Marzocchi, Antonio

    2015-01-01

    Sutureless aortic valve implantation has emerged as an innovative alternative for treatment of aortic stenosis. By avoiding the placement of sutures, this approach aims to improve surgical outcomes by facilitating less traumatic minimally invasive approaches and reducing cross-clamp and cardiopulmonary bypass duration. However, the absence of sutures may have detrimental effects after sutureless interventions, including paravalvular leakages, valve dislocation, and stent-infolding. Transcatheter aortic valve-in-valve implantation (A-ViV) is emerging as a valuable procedure in patients with dysfunctioning biological aortic valves who are deemed inoperable with conventional surgery. Here we present the first-in-man case of trans-femoral implant of a balloon expandable aortic valve in a leaking sutureless self-expandable valve.

  9. Micro-valve pump light valve display

    DOEpatents

    Yeechun Lee.

    1993-01-19

    A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

  10. Micro-valve pump light valve display

    DOEpatents

    Lee, Yee-Chun (Cabin John, MD)

    1993-01-01

    A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

  11. Oil and gas well safety valve

    SciTech Connect

    Sukup, R.A.; Shoaf, J.

    1987-11-17

    An oil or gas well safety valve is described comprising: a valve body having a valve seat therein, a flapper valve, hinge means for supporting the valve from the valve body, control means, positioned within the valve body and to side of the valve to which the valve opens, for engaging the valve at a point removed from the hinge means from selectively applying a force to the valve to pivot the valve between its closed and opened position. The control means comprises a cylinder having upper, intermediate and lower chambers, a control piston moveable in the upper chamber, a control link attached between the control piston and the valve for transmitting the movement of the control piston to the valve and a primary piston moveable in the intermediate chamber.

  12. Valve assembly for internal combustion engine

    SciTech Connect

    Wakeman, R.J.; Shea, S.F.

    1989-09-05

    This patent describes an improvement in a valve assembly for an internal combustion engine of the type including a valve having a valve stem, a valve guideway for mounting this valve for reciprocal strokes between opened and seated position, and spring means for biasing the valve into the seated position. The improvement comprising a valve spool of greater cross-sectional diameter as compared to the valve stem, and a valve spool guideway within which the valve spool is movable during the strokes of the valve, an upper surface of the valve spool and a portion of the spool guideway collectively establishing a damper chamber which varies in volume during the valve strokes. a feed passage for introducing oil into the damper chamber, and a bleed passage for discharging oil from the damper chamber. The bleed passages each laterally opening into the valve spool guideway.

  13. Foot valve for pumping wells

    SciTech Connect

    Dollison, W.W.

    1988-10-11

    This patent describes an apparatus for plugging a well conduit below a rod-type well pump upon withdrawal thereof from the well, the apparatus including: (a) foot valve nipple means having a bore extending therethrough and having attachment means at its upper end for attachment to a well conduit, the foot valve nipple means further including: (i) lateral port means, (ii) an annular seat surface in the foot valve nipple surrounding the bore above the lateral port means, and (iii) support means below the lateral port means and a spaced distance below the annular seat surface providing an upwardly facing stop shoulder; (b) foot valve means in the foot valve nipple means and supportable in its lower, open position by the upwardly facing stop shoulder and movable to an upper, closed position engagement with the annular seat means to plug the same, the foot valve means including: (i) foot valve body means formed with downwardly facing shoulder means engageable with the upwardly facing stop shoulder means in the housing, and a seat surface spaced above the downwardly facing shoulder, and (ii) a fishing neck stem on the foot valve body projecting upwardly therefrom and being engageable by means for lifting the foot valve to a position of engagement with the annular seat surface of the foot valve nipple means, and (c) foot valve operator means attachable to the lower end of a well pump for lifting and lowering the foot valve means between its open and closed positions in the foot valve nipple means, the foot valve operator means.

  14. Transvenous Transcatheter Valve-in-Valve Implantation after Bioprosthetic Tricuspid Valve Failure

    PubMed Central

    Reul, Ross M.; Cannizzaro, Leon; Dougherty, Kathryn G.

    2014-01-01

    We describe the case of a 38-year-old man with a history of metastatic testicular cancer who had undergone multiple thoracic surgical procedures, including tricuspid valve replacement with a bioprosthetic valve as a result of tricuspid involvement of his malignancy. He presented at our outpatient cardiology clinic with worsening fatigue, shortness of breath, and peripheral edema, investigation of which revealed severe tricuspid bioprosthesis stenosis with central regurgitation. Because of the patient's medical history, he was considered to be a high-risk surgical candidate. Therefore, transcatheter tricuspid valve-in-valve implantation of a 26-mm Edwards Sapien® valve was attempted through a transjugular approach. The procedure restored tricuspid valvar competence and substantially improved the patient's symptoms. We discuss the technical aspects of this case and briefly review the usefulness of the valve-in-valve technique in the tricuspid position. PMID:25425983

  15. Variables Influencing the Return on Investment in Management Training Programs: A Utility Analysis of 10 Swiss Cases

    ERIC Educational Resources Information Center

    Chochard, Yves; Davoine, Eric

    2011-01-01

    In this article, we present the utility analysis approach as an alternative and promising approach to measure the return on investment in managerial training programs. This approach, linking economic value with competencies developed by trainees, enables researchers and decision-makers to compare the return on investment from different programs in…

  16. Classroom Management Training, Teaching Experience and Gender: Do These Variables Impact Teachers' Attitudes and Beliefs toward Classroom Management Style?

    ERIC Educational Resources Information Center

    Martin, Nancy K.; Yin, Zenong; Mayall, Hayley

    2006-01-01

    This study represents a continuation of research efforts to further refine the Attitudes and Beliefs on Classroom Control (ABCC) Inventory. The purposes of this study were to investigate the: (1) impact of classroom management training on classroom management style; (2) differences in attitudes toward classroom management between novice and…

  17. Virtual Airport Simulation Technology: Perceptions of Airport Operations Initial Training Program Variables and Effectiveness for Airside Professional Competence

    ERIC Educational Resources Information Center

    DeCarlo, Jeffrey

    2010-01-01

    Air travel is expected to grow by a factor of 2 to 3 times by 2025 and people working in the aviation system, including airport personnel, pilots, and air traffic controllers, must be able to safely and efficiently operate in this arena ("NextGen"). In response to the personnel training and education requirements concomitant with "NextGen,"…

  18. Super seal valve with mechanically retained seal

    SciTech Connect

    Baldridge, M.G.; Sullaway, B.L.

    1986-11-25

    This patent describes an improved valve assembly used in a well cementing tool in a well cementing operation or the like, the valve assembly comprising: an annular valve body housing retained within the cementing tool or the like, the annular valve body housing comprising: a valve seat portion having a bore therethrough; and a valve spring retainer portion secured to the valve seat portion and having a bore therethrough, the valve spring retainer portion comprising: an annular outer cylindrical member having a valve body guide retained therein by means of a plurality of supports extending from the outer cylindrical member to the valve body guide; and a valve body retained within the valve body housing, the valve body including; a valve body head adapted to engage a portion of the interior of the valve body housing, the valve body head comprising: a cylindrical member having a spherical end, frusto-conical outer surface and end surface having, in turn, a blind threaded bore therein; a valve body stem having one end secured to the valve body head, the valve body stem comprising: an elongated cylindrical member having a first threaded surface which releasably threadedly engages the blind threaded bore in the end surface of the valve body head, a first cylindrical surface, a second threaded surface which is slidably received and retained within the valve spring retainer portion of the annular valve body housing; and an elastomeric valve seal retained on the valve body stem in constant, uninterrupted, abutting relationship with the valve body head and adapted to sealingly engage a portion of the interior of the valve body housing, the eleastomeric valve seal comprising.

  19. Fast acting multiple element valve

    DOEpatents

    Yang, Jefferson Y. S. (Orange, CA); Wada, James M. (Torrance, CA)

    1991-01-01

    A plurality of slide valve elements having plural axial-spaced annular parts and an internal slide are inserted into a bulkhead in a fluid conduit from a downstream side of the bulkhead, locked in place by a bayonet coupling and set screw, and project through the bulkhead into the upstream conduit. Pneumatic lines connecting the slide valve element actuator to pilot valves are brought out the throat of the valve element to the downstream side. Pilot valves are radially spaced around the exterior of the valve to permit the pneumatic lines to be made identical, thereby to minimize adverse timing tolerances in operation due to pressure variations. Ring manifolds surround the valve adjacent respective pilot valve arrangements to further reduce adverse timing tolerances due to pressure variations, the manifolds being directly connected to the respective pilot valves. Position sensors are provided the valve element slides to signal the precise time at which a slide reaches or passes through a particular point in its stroke to initiate a calibrated timing function.

  20. Percutaneous Pulmonary Valve Implantation

    PubMed Central

    Lee, Hyoung-Doo

    2012-01-01

    Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs. PMID:23170091

  1. Rotary multiposition valve

    SciTech Connect

    Barclay, J. A.; Dyson, J. E.

    1985-11-19

    The disclosure is directed to a rotary multiposition valve for selectively directing the flow of a fluid through a plurality of paths. The valve comprises an inner member and a hollow housing with a row of ducts on its outer surface. The ducts are in fluid communication with the housing. An engaging section of the inner member is received in the housing. A seal divides the engaging section into a hollow inlet segment and a hollow outlet segment. A plurality of inlet apertures are disposed in the inlet segment and a plurality of outlet apertures are disposed in the outlet segment. The inlet apertures are disposed in a longitudinally and radially spaced-apart pattern that can be a helix. The outlet apertures are disposed in a corresponding pattern. As the inner member is rotated, whenever an inlet aperture overlaps one of the ducts, the corresponding outlet aperture overlaps a different duct, thus forming a fluid pathway.

  2. Rotary multiposition valve

    SciTech Connect

    Barclay, John A. (Los Alamos, NM); Dyson, Jack E. (Los Alamos, NM)

    1985-01-01

    The disclosure is directed to a rotary multiposition valve for selectively directing the flow of a fluid through a plurality of paths. The valve comprises an inner member and a hollow housing with a row of ducts on its outer surface. The ducts are in fluid communication with the housing. An engaging section of the inner member is received in the housing. A seal divides the engaging section into a hollow inlet segment and a hollow outlet segment. A plurality of inlet apertures are disposed in the inlet segment and a plurality of outlet apertures are disposed in the outlet segment. The inlet apertures are disposed in a longitudinally and radially spaced-apart pattern that can be a helix. The outlet apertures are disposed in a corresponding pattern. As the inner member is rotated, whenever an inlet aperture overlaps one of the ducts, the corresponding outlet aperture overlaps a different duct, thus forming a fluid pathway.

  3. Rotary multiposition valve

    SciTech Connect

    Barclay, J.A.; Dyson, J.E.

    1984-04-06

    The disclosure is directed to a rotary multiposition valve for selectively directing the flow of a fluid through a plurality of paths. The valve comprises an inner member and a hollow housing with a row of ducts on its outer surface. The ducts are in fluid communication with the housing. An engaging section of the inner member is received in the housing. A seal divides the engaging section into a hollow inlet segment and a hollow outlet segment. A plurality of inlet apertures are disposed in the inlet sgegment and a plurality of outlet apertures are disposed in the outlet segment. The inlet apertures are disposed in a longitudinally and radially spaced-apart pattern that can be a helix. The outlet apertures are disposed in a corresponding pattern. As the inner member is rotated, whenever an inlet aperture overlaps one of the ducts, the corresponding outlet aperture overlaps a different duct, thus forming a fluid pathway.

  4. Stemless ball valve

    NASA Technical Reports Server (NTRS)

    Burgess, Kevin (Inventor); Yakos, David (Inventor); Walthall, Bryan (Inventor)

    2011-01-01

    A stemless ball valve comprising two flanges and a ball with a channel, two axis pins and two travel pins. One end of each axis and travel pin is fixedly attached to the ball, and the other end of each axis pin is lodged into a notch in the first or second flange such that the axis pin is allowed to rotate in the notch. The guide sleeve comprises two channels, and one end of each travel pin is situated within one of the two channels in the guide sleeve. An outer magnetic cartridge causes the inner magnetic cartridge and guide sleeve to rotate, and when the guide sleeve rotates, the travel pins move up and down within the channels in the guide sleeve. The movement of the travel pins within the channels in the guide sleeve causes the ball to rotate, thereby opening and closing the ball valve.

  5. Fast-acting valve and uses thereof

    DOEpatents

    Meyer, James A. (Espanola, NM)

    1982-01-01

    A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

  6. Fast-acting valve and uses thereof

    DOEpatents

    Meyer, J.A.

    1980-05-16

    A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

  7. Solenoid Valve With Self-Compensation

    NASA Technical Reports Server (NTRS)

    Woeller, Fritz H.; Matsumoto, Yutaka

    1987-01-01

    New solenoid-operated miniature shutoff valve provides self-compensation of differential pressure forces that cause jamming or insufficient valve closure as in single-seal valves. Dual-seal valve is bidirectional. Valve simultaneously seals both inlet and outlet tubes by pressing single disk of silicone rubber against ends of both.

  8. Performance Characteristics of an Isothermal Freeze Valve

    SciTech Connect

    Hailey, A.E.

    2001-08-22

    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.

  9. Modeling and simulation of the proportional valve control system for the turbocharger

    Microsoft Academic Search

    Sheng-Guan Qu; Yi-Hua Zhang; Zi-Guo Ye; Ming Shao; Wei Xia

    2010-01-01

    The key technology of the advanced variable nozzle turbocharger is the proportional valve control system. In this article, the fundamental dynamic equations of the proportional valve control system for the turbocharger are deduced by analyzing the principle of operation, the mathematical model of the control system is established, and the control system is simulated by using the MATLAB\\/Simulink. The static

  10. Self-compensating solenoid valve

    NASA Technical Reports Server (NTRS)

    Woeller, Fritz H. (inventor); Matsumoto, Yutaka (inventor)

    1987-01-01

    A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug.

  11. Update of transcatheter valve treatment

    PubMed Central

    Liu, Xian-bao; Wang, Jian-an

    2013-01-01

    Transcatheter valve implantation or repair has been a very promising approach for the treatment of valvular heart diseases since transcatheter aortic valve implantation (TAVI) was successfully performed in 2002. Great achievements have been made in this field (especially TAVI and transcatheter mitral valve repair—MitraClip system) in recent years. Evidence from clinical trials or registry studies has proved that transcatheter valve treatment for valvular heart diseases is safe and effective in surgical high-risk or inoperable patients. As the evidence accumulates, transcatheter valve treatment might be an alterative surgery for younger patients with surgically low or intermediate risk valvular heart diseases in the near future. In this paper, the updates on transcatheter valve treatment are reviewed. PMID:23897785

  12. Streamline coal slurry letdown valve

    DOEpatents

    Platt, Robert J. (Dover, NJ); Shadbolt, Edward A. (Basking Ridge, NJ)

    1983-01-01

    A streamlined coal slurry letdown valve is featured which has a two-piece throat comprised of a seat and seat retainer. The two-piece design allows for easy assembly and disassembly of the valve. A novel cage holds the two-piece throat together during the high pressure letdown. The coal slurry letdown valve has long operating life as a result of its streamlined and erosion-resistance surfaces.

  13. Streamline coal slurry letdown valve

    DOEpatents

    Platt, R.J.; Shadbolt, E.A.

    1983-11-08

    A streamlined coal slurry letdown valve is featured which has a two-piece throat comprised of a seat and seat retainer. The two-piece design allows for easy assembly and disassembly of the valve. A novel cage holds the two-piece throat together during the high pressure letdown. The coal slurry letdown valve has long operating life as a result of its streamlined and erosion-resistance surfaces. 5 figs.

  14. Sequenced drive for rotary valves

    DOEpatents

    Mittell, Larry C. (Palos Verdes Estates, CA)

    1981-01-01

    A sequenced drive for rotary valves which provides the benefits of applying rotary and linear motions to the movable sealing element of the valve. The sequenced drive provides a close approximation of linear motion while engaging or disengaging the movable element with the seat minimizing wear and damage due to scrubbing action. The rotary motion of the drive swings the movable element out of the flowpath thus eliminating obstruction to flow through the valve.

  15. Mitral Valve Prolapse (For Parents)

    MedlinePLUS

    ... a Heart Defect Atrial Septal Defect Heart and Circulatory System Congenital Heart Defects Arrhythmias Heart Murmurs Your Heart & Circulatory System Mitral Valve Prolapse Marfan Syndrome Ventricular Septal Defect ...

  16. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J. (Oak Ridge, TN)

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separtion of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve.

  17. Potential flow in engine valves

    NASA Technical Reports Server (NTRS)

    Eck, Bruno

    1925-01-01

    The extensive applicability of the hydrodynamic theory to the problems of engine construction is clearly shown in the following attempt to determine by exact methods the nature of the flow in valves under variously restricted conditions. Observation shows that two principal kinds of flow occur in simple flat-seated valves. For small valve lifts, the flow is along the horizontal wall and is therefore deflected 90 degrees, but for greater valve lifts the flow separates and forms a free stream, whose angle of deflection naturally increases with increasing lift. Both these kinds of flow can, in fact, be theoretically explained

  18. Innovative Stemless Valve Eliminates Emissions

    NASA Technical Reports Server (NTRS)

    2008-01-01

    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.

  19. Transfemoral and transseptal valve-in-valve implantation into a failing mitral xenograft with a balloon-expandable biological valve.

    PubMed

    Schaefer, Ulrich; Frerker, Christian; Schewel, Dimitry; Thielsen, Thomas; Meincke, Felix; Kreidel, Felix; Kuck, Karl-Heinz

    2012-12-01

    Valve-in-valve implantation for degenerated surgical bioprosthetic valves is becoming an increasingly accepted approach in selected high-risk patients. In the past, valve-in-valve implantations have been mainly performed in aortic position and only rarely in mitral position. We describe the case of an 81-year-old female patient with severe mitral regurgitation of a degenerated Carpentier-Edwards biological prosthesis treated by transfemoral and transseptal implantation of a SAPIEN-XT valve. PMID:23176928

  20. Whitey Gauge and Root Valves (VPS)

    SciTech Connect

    MISKA, C.

    2000-10-17

    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.

  1. All metal valve structure for gas systems

    DOEpatents

    Baker, Ray W. (Hamilton, OH); Pawlak, Donald A. (Centerville, OH); Ramey, Alford J. (Miamisburg, OH)

    1984-11-13

    A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

  2. IADC mud equipment manual. Handbook 10: Valves

    SciTech Connect

    Not Available

    1985-01-01

    Contents include: Terminology, Application of valve types: gate, ball, butterfly, check, plug, safety relief, and choke. Codes of the valve industry. End connections. Safety precautions. Fittings. Automatic actuators and control consoles. Internal forces affecting operating torque and valve life expectancy.

  3. Low energy high pressure miniature screw valve

    DOEpatents

    Fischer, Gary J. (Sandia Park, NM); Spletzer, Barry L. (Albuquerque, NM)

    2006-12-12

    A low energy high pressure screw valve having a valve body having an upper portion and a lower portion, said lower portion of said valve body defining an inlet flow passage and an outlet flow passage traversing said valve body to a valve seat, said upper portion of said valve body defining a cavity at said valve seat, a diaphragm restricting flow between said upper portion of said valve body and said lower portion, said diaphragm capable of engaging said valve seat to restrict fluid communication between said inlet passage and said outlet passage, a plunger within said cavity supporting said diaphragm, said plunger being capable of engaging said diaphragm with said valve seat at said inlet and outlet fluid passages, said plunger being in point contact with a drive screw having threads engaged with opposing threads within said upper portion of said valve body such engagement allowing motion of said drive screw within said valve body.

  4. Assessing the risk of aortic valve replacement for severe aortic stenosis in the transcatheter valve era.

    PubMed

    Mathew, Verghese; Greason, Kevin L; Suri, Rakesh M; Leon, Martin B; Nkomo, Vuyisile T; Mack, Michael J; Rihal, Charanjit S; Holmes, David R

    2014-10-01

    Surgical aortic valve replacement had been the only definitive treatment of severe aortic stenosis before the availability of transcatheter valve technology. Historically, many patients with severe aortic stenosis had not been offered surgery, largely related to professional and patient perception regarding the risks of operation relative to anticipated benefits. Such patients have been labeled as "high risk" or "inoperable" with respect to their suitability for surgery. The availability of transcatheter aortic valve replacement affords a new treatment option for patients previously not felt to be optimal candidates for surgical valve replacement and allows for the opportunity to reexamine the methods for assessing operative risk in the context of more than 1 available treatment. Standardized risk assessment can be challenging because of both the imprecision of current risk scoring methods and the variability in ascertaining risk related to operator experience as well as local factors and practice patterns at treating facilities. Operative risk in actuality is not an absolute but represents a spectrum from very low to extreme, and the conventional labels of high risk and inoperable are incomplete with respect to their utility in clinical decision making. Moving forward, the emphasis should be on developing an individual assessment that takes into account procedure risk as well as long-term outcomes evaluated in a multidisciplinary fashion, and incorporating patient preferences and goals in a model of shared decision making. PMID:24958696

  5. Cardiac Valve Interstitial Cells: Regulator of Valve Structure and Function

    Microsoft Academic Search

    1997-01-01

    Cardiac valve interstitial cell tissue is present throughout the valve. The molecular biology of this cell type is not well known. The purpose of this review is to present our current understanding of the structure and function of valvular interstitial cells and to describe experimental approaches available to study the structure and regulation of interstitial cell function and the interaction

  6. Exploring Inclusion Preservice Training Needs: A Study of Variables Associated with Attitudes and Self-Efficacy Beliefs

    ERIC Educational Resources Information Center

    Romi, Shlomo; Leyser, Yona

    2006-01-01

    The study examined attitudes towards inclusion and sense of efficacy of 1155 Israeli preservice teachers and variables related to these beliefs. Participants responded to an "Options related to inclusion scale", and a "Teacher efficacy scale". Findings revealed strong support for the principle of inclusion, yet also support for segregated special…

  7. Television Performance Effectiveness: A Study of Related Variables and the Effects of Inservice Training and Evaluative Feedback.

    ERIC Educational Resources Information Center

    Hatch, James Cordell

    Theoretically, a number of demographic, personality, attitudinal, cognitive, and performance variables were selected for examining television performance effectiveness. The experiment, conducted within the workshop context, was replicated in 1965 with a total of 62 participants. Each year subjects were placed into three random groups, stratified…

  8. Heart Valve Replacement

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program reviews the symptoms and treatments of heart valve defects, in particular, the benefits and risks of surgery. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

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

    NASA Technical Reports Server (NTRS)

    Fishbach, Sean R.; Davis, R. Benjamin

    2010-01-01

    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.

  10. Gasoline-like Fuel Effects on High-load, Boosted HCCI Combustion Employing Negative Valve Overlap Strategy

    SciTech Connect

    Kalaskar, Vickey B [ORNL] [ORNL; Szybist, James P [ORNL] [ORNL; Splitter, Derek A [ORNL] [ORNL

    2014-01-01

    In recent years a number of studies have demonstrated that boosted operation combined with external EGR is a path forward for expanding the high load limit of homogeneous charge compression ignition (HCCI) operation with the negative valve overlap (NVO) valve strategy. However, the effects of fuel composition with this strategy have not been fully explored. In this study boosted HCCI combustion is investigated in a single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), laboratory pressurized intake air, and a fully-variable hydraulic valve actuation (HVA) valve train. Three fuels with significant compositional differences are investigated: regular grade gasoline (RON = 90.2), 30% ethanol-gasoline blend (E30, RON = 100.3), and 24% iso-butanol-gasoline blend (IB24, RON = 96.6). Results include engine loads from 350 to 800 kPa IMEPg for all fuels at three engine speeds 1600, 2000, and 2500 rpm. All operating conditions achieved thermal efficiency (gross indicated efficiency) between 38 and 47%, low NOX emissions ( 0.1 g/kWh), and high combustion efficiency ( 96.5%). Detailed sweeps of intake manifold pressure (atmospheric to 250 kPaa), EGR (0 25% EGR), and injection timing are conducted to identify fuel-specific effects. The major finding of this study is that while significant fuel compositional differences exist, in boosted HCCI operation only minor changes in operational conditions are required to achieve comparable operation for all fuels. In boosted HCCI operation all fuels were able to achieve matched load-speed operation, whereas in conventional SI operation the fuel-specific knock differences resulted in significant differences in the operable load-speed space. Although all fuels were operable in boosted HCCI, the respective air handling requirements are also discussed, including an analysis of the demanded turbocharger efficiency.

  11. Transcatheter valves: a brave New World.

    PubMed

    Vesely, Ivan

    2010-09-01

    Over the past five years, transcatheter valves have stimulated the attention of physicians, engineers, and investors. Transcatheter valve design and implantation techniques depart from the time-proven features of surgical valves, and this has an important impact on the safety and efficacy of prosthetic valve therapy. Herein is reviewed the performance of transcatheter valve procedures in comparison to surgical valves, together with a summary of the specific design features of several emerging transcatheter valves. How the current and future generation transcatheter valves are likely to impact on patient treatment is also explored. PMID:21053731

  12. Chrysophyte cyst-inferred variability of warm season lake water chemistry and climate in northern Poland: training set and downcore reconstruction

    NASA Astrophysics Data System (ADS)

    Hernández-Almeida, Iván; Grosjean, Martin; Tylmann, Wojciech; Bonk, Alicja

    2014-05-01

    Transfer Functions based on modern training sets are well established and powerful tools in quantitative paleolimnology and environmental/climate reconstructions. Lake sediments are excellent natural archive to reconstruct long-term climate and environmental fluctuations. In this sense, the project 'Climate of northern Poland during the last 1000 years: Constraining the future with the past' (CLIMPOL) aims to develop quantitative climate reconstruction in northern Poland during the last millennium using lake sediments. The Polish training set consists of Chrysophyte cyst (golden brown algae, class Chrysophyceae) sediment trap and surface sediment samples, and data for 19 environmental variables collected from 50 lakes in northern Poland. Canonical correspondence analyses (CCA) revealed that water electric conductivity, total nitrogen, total phosphorous, turbidity, cation and anion compositions (Ca2+, HCO3-) contributed significantly to explaining chrysophytes distribution in the lakes of the training set. A quantitative transfer function was then developed to estimate Ca2+ (log10 transformed) from modern chrysophyte cysts assemblages using weighted-averaging regression (WA) with classical deshrinking. The bootstrapped regression coefficient (R2boot) was 0.68, with a root-mean square error of prediction (RMSEP) of 0.143 (log10 units). The calibration model was applied to a varved sedimentary sequence (AD 1898-2010) from Lake ?abi?skie, Masurian Lakeland (NE Poland). Cyst-inferred lake water Ca2+ concentrations were significantly correlated with zonal wind speed (m•s-1) (R=0.50; padj<0.001; AD 1898-2010; 3-yr filtered). We suggest that these changes in calcite precipitation in Lake ?abi?skie depend on the lake mixing regime, driven by westerly winds. Observational data from this lake show that the Ca2+ variability in the epilimnion depends on the efficiency of Ca2+ scavenging by CaCO3 precipitation in early summer which, in turn, is a function of water column stratification, temperature and the wind regime from late spring to early fall. This study demonstrates that chrysophyte cysts assemblages in Polish lakes respond to hydrochemical factors driven by climate variability.

  13. Mitral valve disease: a cardiologic-surgical interaction.

    PubMed

    Barlow, J B

    1996-10-01

    The respective roles of cardiologist and cardiac surgeon in the operative management of any specific case of mitral valve disease are variable. The range from the prevalent complete predominance of the surgeon through meaningful interaction between the two, concerning the timing and type of surgery, to predominance of the cardiologist when the surgeon accepts a role of technician. There are a number of scenarios in mitral valve surgery in which a reduced risk of postoperative hospital mortality and morbidity, by performing the simplest and shortest procedure, have to be balanced against enhanced peri-operative problems when other aspects are addressed that improve, sometimes markedly, the long-term prognosis. It is argued that a mildly stenotic aortic valve should often be replaced at the time of mitral valve surgery; that despite technical difficulties and a variable long-term postoperative course, surgeons should continue to repair rather than replace the mitral valves of young patients with severe mitral regurgitation despite the invariable presence of active rheumatic carditis; and that excess leaflet tissue and lax chordae in cases of degenerative mitral regurgitation are casually related to multifocal and potentially fatal ventricular ectopy. The crucial but neglected role of an organically abnormal tricuspid anulus in allowing dilatation and hence tricuspid regurgitation in patients with rheumatic mitral valve disease is considered in some detail. Such dilatation may occur late after mitral valve surgery for rheumatic disease, has generally and incorrectly been regarded as "functional" tricuspid regurgitation, contributes importantly to the postoperative "restriction-dilatation syndrome" and can be effectively prevented, or when once established then surgically managed, by a modified De Vega anuloplasty. Finally it is believed that, unlike mitral balloon valvuloplasty in selected instances, successful tricuspid balloon valvuloplasty can never be accomplished without causing significant tricuspid regurgitation and the procedure should be abandoned. PMID:8950247

  14. Valve designed with elastic seat

    NASA Technical Reports Server (NTRS)

    Mac Glashan, W. F., Jr.

    1965-01-01

    Absolute valve closure is accomplished by a machined valve with an axially annular channel which changes the outlet passage into a thin tubular elastic seat member with a retainer backup ring. The elasticity of the seat provides tight conformity to ball irregularity.

  15. Valve-"Health"-Monitoring System

    NASA Technical Reports Server (NTRS)

    Jensen, Scott L.; Drouant, George J.

    2009-01-01

    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.

  16. Surface treatment for valve seats

    NASA Technical Reports Server (NTRS)

    Macglashan, W. F., Jr.

    1970-01-01

    Valve with embedded fine particles of diamond in the metal surface of the valve seat resists galling, corrosion, erosion, and cold welding. Diamond powder has an average particle diameter of 0.01 micron and is used with a standard fine diamond polishing compound.

  17. Periostin regulates atrioventricular valve maturation

    Microsoft Academic Search

    Russell A. Norris; Ricardo A. Moreno-Rodriguez; Yukiko Sugi; Stanley Hoffman; Jenny Amos; Mary M. Hart; Jay D. Potts; Richard L. Goodwin; Roger R. Markwald

    2008-01-01

    Cardiac valve leaflets develop from rudimentary structures termed endocardial cushions. These pre-valve tissues arise from a complex interplay of signals between the myocardium and endocardium whereby secreted cues induce the endothelial cells to transform into migratory mesenchyme through an endothelial to mesenchymal transformation (EMT). Even though much is currently known regarding the initial EMT process, the mechanisms by which these

  18. Living with Heart Valve Disease

    MedlinePLUS

    ... Explore Heart Valve Disease What Is... Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical Trials Links Related Topics Congenital Heart Defects Endocarditis Heart Murmur How the Heart Works Mitral Valve Prolapse Send a link to NHLBI to someone by ...

  19. Electro-Mechanical Coaxial Valve

    NASA Technical Reports Server (NTRS)

    Patterson, Paul R (Inventor)

    2004-01-01

    Coaxial valves usually contain only one moving part. It has not been easy, then, to provide for electric motor actuation. Many actuators being proposed involve designs which lead to bulky packages. The key facing those improving coaxial valves is the provision of suitable linear actuation. The valve herein indudes a valve housing with a flow channel there-through. Arranged in the flow channel is a closing body. In alignment with the closing body is a ball screw actuator which includes a ball nut and a cylindrical screw. The ball nut sounds a threaded portion of the cylindrical screw. The cylindrical screw is provided with a passageway there-through through which fluid flows. The cylindrical screw is disposed in the flow channel to become a control tube adapted to move toward and away from the valve seat. To rotate the ball nut an actuating drive is employed driven by a stepper motor.

  20. A Parylene MEMS Electrothermal Valve

    PubMed Central

    Li, Po-Ying; Givrad, Tina K.; Holschneider, Daniel P.; Maarek, Jean-Michel I.; Meng, Ellis

    2011-01-01

    The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbolus infusion pump, and the in vivo functionality for the appropriateness of use of this pump for future brain mapping applications in small animals was demonstrated. PMID:21350679

  1. Impact of Aerobic Exercise Training on Heart Rate Variability and Functional Capacity in Obese Women After Gastric Bypass Surgery

    Microsoft Academic Search

    Viviane Castello; Rodrigo Polaquini Simões; Daniela Bassi; Aparecida Maria Catai; Ross Arena; Audrey Borghi-Silva

    Background  Obesity is a major public health concern on a global scale. Bariatric surgery is among the treatment options, resulting in\\u000a significant and sustainable weight loss as well as amelioration of comorbidities. The purpose of this study was to evaluate\\u000a whether a 12-week aerobic exercise program positively impacts heart rate variability (HRV) and functional capacity after gastric\\u000a bypass surgery (GBS) in

  2. Intensifier pump with integrated check valve

    SciTech Connect

    Laborde, R.G.; Jendrzejek, G.S.

    1983-11-01

    A high pressure check valve is described for a pressure multiplier cylinder. It is secured in the end of the cylinder so as to reduce the stress on the check valve due to cyclic loading. The check valve can deliver high pressure fluid on the order of 60,000 psi from the cylinder of a reciprocating pressure multiplier pump. A check valve assembly which contains the high pressure check valve also contains a low pressure check valve for the admission of low pressure fluid to the cylinder. The check valve has a coaxial bore for delivery of high pressure fluid which up to the valve seat subjects the valve to cyclic loading, and beyond the valve seat subjects the valve to a substantially constant high pressure. 2 claims.

  3. Dump valve for use with downhole motor

    SciTech Connect

    Poston, J.B.

    1981-03-31

    A dump valve having a valve seat and a valve member is located in a string of drill pipe above a downhole motor. The dump valve connects the inside of the drill string with the annulus and allows drilling mud to flow freely therebetween when drilling mud is not being pumped through the drill string to operate the downhole motor. The valve member is made of a deformable resilient material such as rubber. It is held away from the valve seat by spacers until the pressure drop across the valve member is sufficient to deform the valve member and move it past the spacers into engagement with the valve seat. When the pressure differential is relieved, the valve member will return to its normal, unstressed shape opening the valve.

  4. Downhole surge valve for earth boring apparatus

    SciTech Connect

    Lee, D.W.

    1990-05-29

    This patent describes a boring tool assembly having an underground percussion mole boring tool powered by a working fluid, the tool being driven through the earth by a rigid drill string pushed by a drilling frame, and a downhole valve assembly fixed between the downhole end of the drill string and the too, the improved downhole valve assembly. It comprises: a valve spool having an open first end, a closed second end and a peripheral sidewall, an axial bore extending partly through the valve spool from the open first end; a radial passage adjacent the closed second and of the valve spool, the radial passage extending radially from the valve spool axial bore through the valve spool peripheral sidewall; an axial groove in the peripheral sidewall of the valve spool; a valve body having a first end, a second end and a peripheral sidewall, an axial bore extending through the valve body, the valve spool extending through the valve body axial bore so that the second end of the valve body is adjacent the closed second end of the valve spool, the valve spool being axially moveable within the valve body axial bore; an axial slot; a free-floating key element; a valve housing; and seal means.

  5. Variable venturi type carburetor and associated method

    SciTech Connect

    Tahata, M.

    1986-10-07

    A variable venturi type carburetor is described which consists of a carburetor body provided with a suction passage therein, a slide valve supported by the body for movement across the suction passage to function as a variable venturi, a butterfly throttle valve pivotably supported by the carburetor body downstream of the slide valve, an interlocking means connecting the slide valve and the butterfly throttle valve for operation in correspondence with one another. The carburetor body comprises a side portion including a wall defining a housing recess, and a cover member fixed to the carburetor body to close the housing recess and form a housing chamber in which the interlocking means is arranged. The cover member includes an integral loosening-preventing portion, the interlocking means including a setting nut associated with the slide valve. The loosening-preventing portion engages the setting nut for preventing turning thereof, thereby to prevent the setting nut from being loosened.

  6. Self-Rupturing Hermetic Valve

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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-energizing and requires low force compared to current pyrotechnic-based burst disk hermetic valves. This is a novel design for producing a single-use, self-rupturing, hermetically sealed valve for isolation of pressurized gas and/or liquids. This design can also be applied for single-use disposable valves for chemical instruments. A welded foil diaphragm is fully supported by two mated surfaces that are machined to micron accuracies using EDM. To open the valve, one of the surfaces is moved relative to the other to (a) remove the support creating an unsupported diaphragm that ruptures due to over pressure, and/or (b) produce tension in the diaphragm and rupture it.

  7. Valve for controlling solids flow

    DOEpatents

    Feldman, David K. (Fairlawn, NJ)

    1980-01-01

    A fluidized solids control valve is disclosed that is particularly well adapted for use with a flow of coal or char that includes both large particles and fines. The particles may or may not be fluidized at various times during the operation. The valve includes a tubular body that terminates in a valve seat covered by a normally closed closure plate. The valve body at the seat and the closure plate is provided with aligned longitudinal slots that receive a pivotally supported key plate. The key plate is positionable by an operator in inserted, intermediate and retracted positions respecting the longitudinal slot in the valve body. The key plate normally closes the slot within the closure plate but is shaped and aligned obliquely to the longitudinal slot within the valve body to provide progressively increasing slot openings between the inserted and retracted positions. Transfer members are provided between the operator, key plate and closure plate to move the closure plate into an open position only when the key plate is retracted from the longitudinal slot within the valve body.

  8. Cavitation guide for control valves

    SciTech Connect

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

    1993-04-01

    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.

  9. Mechanical aortic valve-on-valve replacement in previous Bentall procedure: an alternate technique.

    PubMed

    Manoly, Imthiaz; Krishnan, Monica; Hoschtitzky, J Andreas; Hasan, Ragheb

    2014-09-01

    Acute aortic valve regurgitation due to thrombosed prosthetic valve can present as a surgical emergency. This article reports a successful and unusual management of a young pregnant female patient who presented with acute aortic valve regurgitation due to a thrombosed mechanical aortic valve. As the patient had previous multiple cardiac surgeries, the options were limited for repeat aortic valve or aortic root replacement. The patient had caesarean section followed by implantation of a mechanical valve-on-valve in a previously placed composite valved conduit. This technique may be useful for reoperative valve replacement in the setting of a prior mechanical Bentall patient. PMID:25193228

  10. The effects of autogenic-feedback training on motion sickness severity and heart rate variability in astronauts

    NASA Technical Reports Server (NTRS)

    Toscano, William B.; Cowings, Patricia S.

    1994-01-01

    Space motion sickness (SMS) affects 50 percent of all people during early days of spaceflight. This study describes the results of two Shuttle flight experiments in which autogenic-feedback training (AFT), a physiological conditioning method, was tested as a treatment for this disorder. Of the six who were designated as flight subjects (two women and four men), three were given treatment and three served as controls (i.e., no AFT). Treatment subjects were given 6 hours of preflight AFT. Preflight results showed that AFT produced a significant increase in tolerance to rotating chair motion sickness tests. Further, this increased tolerance was associated with changes in specific physiological responses and reports of reduced malaise. Flight results showed that two of the three control subjects experienced repeated vomiting on the first mission day, while one subject experienced only moderate malaise. Of the three treatment subjects, one experienced mild discomfort, one moderate discomfort, and one severe motion sickness. Only the three control subjects took medication for symptom suppression. Measures of cardiac function reflective of vagal control were shown to be affected especially strongly on the first day of space flight. AFT given for control of heart rate, respiration, and other autonomic activity influenced both the vagal control measures and SMS. These data suggest that AFT may be an effective treatment for space motion sickness; however, this cannot be demonstrated conclusively with the small number of subjects described.

  11. Designing and commissioning variable flow hydronic systems

    Microsoft Academic Search

    1993-01-01

    Direct return variable flow hydronic systems (VFHS) must (in this author's opinion) be designed to be self-balancing. However, in practice, many design engineers will use customary pipe sizing routines, piping detail drawings and specifications that apply to more familiar constant flow systems. Substituting a two-way valve in place of a three-way valve and bypass pipe, while retaining the balancing valve

  12. Stemless ball valve

    NASA Technical Reports Server (NTRS)

    Burgess, Kevin (Inventor); Yakos, David (Inventor); Walthall, Bryan (Inventor)

    2012-01-01

    A stemless ball valve comprising: a right flange; left flange; ball with an axis pin and two travel pins; ball seal on either side of the ball; guide sleeve with inner walls comprising two channels; cartridge guide holder; inner magnetic cartridge; and outer magnetic cartridge. The ball is situated inside of the guide sleeve, and a travel pin is located in each of the two channels. The guide sleeve is situated inside of the cartridge guide holder, which is located adjacent to and outside of the inner magnetic cartridge and secured to the inner magnetic cartridge such that when the inner magnetic cartridge rotates, the cartridge guide holder also rotates. The cartridge guide holder is secured to the guide sleeve such that when the cartridge guide holder rotates, the travel pins move within the channels in the inner walls of the guide sleeve, thereby causing the ball to rotate.

  13. Performance testing of subsurface safety valves

    Microsoft Academic Search

    J. L. Holster; R. L. Bass; E. C. Schroeder

    1975-01-01

    A test facility for performance testing of oil and gas well subsurface safety valves in accordance with the American Petroleum Institute's Spec. 14A, Specification for Subsurface Safety Valves is described. The facility is designed to ensure that the valves meet minimum specifications concerning leak rates, opening and closing operations, erosion resistance, and pressure ratings. Four separate valves up to 4-in

  14. GAS VALVES FOR NUCLEAR POWER STATIONS

    Microsoft Academic Search

    Blakeborough

    1960-01-01

    A review is presented for gas valves for nuclear power stations, both ; gas-cooled and liquid-cooled. Such valves are generally of cast construction and ; hence more susceptible to leakage than fabricated valves. In many valves, ; gaskets are used to reduce casting weight. The most troublesome source of ; leakage is the spindle, but graphited asbestos packing can give

  15. Dump valve for use with downhole motor

    Microsoft Academic Search

    1981-01-01

    A dump valve having a valve seat and a valve member is located in a string of drill pipe above a downhole motor. The dump valve connects the inside of the drill string with the annulus and allows drilling mud to flow freely therebetween when drilling mud is not being pumped through the drill string to operate the downhole motor.

  16. Heart Valve Lesson Plan Biomedical Engineering

    E-print Network

    Provancher, William

    Heart Valve Lesson Plan Biomedical Engineering Objective · Introduce students to biomedical Learning Outcomes · Students will understand the role and function of heart valves. · Students will learn does a heart valve work? · Why do we need to replace heart valves? Time Required (Itemized) · Lecture

  17. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...requirements. (b) Each cast iron and plastic valve must comply with the following...s.i. (7 Mpa) gage; and (2) Welding is not used on any ductile iron...

  18. Flapper mount for well safety valve

    Microsoft Academic Search

    E. D. Lueders; B. A. Roth

    1991-01-01

    This patent describes a subsurface well safety valve for controlling the fluid flow through a well conduit. It comprises a housing having an axial bore, the housing including a one-piece flapper mount, a flapper valve closure member movable between open and closed positions relative to the valve seat and supported from the mount, the valve closure member being a sector

  19. Pressure regulating and relief valve assembly

    Microsoft Academic Search

    W. J. Nicholl; J. H. Leggett; J. R. Shychick

    1984-01-01

    A pressure regulating and relief valve assembly, such as an assembly positionable in a lower portion of a well casing are disclosed. The valve assembly has a main relief valve assembly or back pressure regulator that is designed to open when the steam pressure exceeds a first predetermined value. A secondary relief valve assembly is provided to vent excess pressure

  20. The Delta Valve: a physiologic shunt system

    Microsoft Academic Search

    David A. Watson

    1994-01-01

    PS Medical has advanced the state-of-the-art in hydrocephalus valve technology with the introduction of the Delta Valve. The Delta Valve is designed upon the premise that the shunted patient should have intracranial pressure (ICP) maintenance within a normal range regardless of cerebrospinal fluid (CSF) flow rate or body position. All previous valves have performance characteristics that are greatly influenced by

  1. Solar energy operated irrigation surge valve

    Microsoft Academic Search

    1985-01-01

    A valve body is provided having axially spaced annular valve seats defining fluid outlets for the body. The body includes an inlet opening into the interior thereof between the seats and a disc valve is supported within the body for axial shifting between the seats. A drive mechanism for the valve disc is drivingly connected thereto and is operative to

  2. Valve mechanism of internal combustion engine

    Microsoft Academic Search

    S. Morita; K. Sato; Y. Asaoka; I. Harada; T. Hirano

    1987-01-01

    This patent describes a valve mechanism of an internal combustion engine, the valve mechanism comprising: a hydraulic valve lifter assembled in a recess of a rocker arm pivotably connected to a rocker shaft, the shaft extending through a hole in the rocker arm. The hydraulic valve lifter has a lifter body slidably inserted in the recess, a plunger slidably inserted

  3. Multi-port valve

    DOEpatents

    Lewin, Keith F. (Calverton, NY)

    1997-04-15

    A multi-port valve for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO.sub.2) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets therethrough disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending therethrough disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind.

  4. Multi-port valve

    DOEpatents

    Lewin, K.F.

    1997-04-15

    A multi-port valve is described for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO{sub 2}) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets there through disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending there through disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind. 7 figs.

  5. TRAINING IN INDUSTRY.

    ERIC Educational Resources Information Center

    GLASER, ROBERT

    THIS CHAPTER IN A LARGER WORK ON INDUSTRIAL PSYCHOLOGY DEALS LARGELY WITH THE NEED TO SPECIFY TRAINING OBJECTIVES THROUGH JOB ANALYSIS, USES OF TESTING IN TRAINEE SELECTION, TRAINING VARIABLES AND LEARNING PROCESSES, TRAINING TECHNOLOGY (MAINLY THE CHARACTERISTICS OF PROGRAMED INSTRUCTION), THE EVALUATION OF PROFICIENCY, THE VALUE OF…

  6. Transaortic transcatheter aortic valve implantation using the Edwards Sapien valve.

    PubMed

    Bapat, Vinnie Vinayak; Attia, Rizwan

    2012-01-01

    Transcatheter aortic valve implantation using Edwards Sapien Valve can be carried out through the ascending aorta. In the majority of patients, the ascending aorta is approached through a partial upper J-sternotomy. The sternotomy extends into the right second or third right intercostal space. The pericardium is opened in midline and the top of the ascending aorta is exposed. Two purse-string sutures are then placed on the ascending aorta and Sapien valve implantation is carried out using the Ascendra delivery system with the valve mounted in a reverse fashion to that of a transapical approach. Owing to the familiarity of the surgeons with exposing the aorta and placing purse-strings for cannulation, this procedure is within the comfort zone of surgeons compared with the transapical approach. Advantages, contra--indications, surgical technique and results are also discussed. PMID:24414720

  7. Ferroelectric Fluid Flow Control Valve

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    An active valve is controlled and driven by external electrical actuation of a ferroelectric actuator to provide for improved passage of the fluid during certain time periods and to provide positive closure of the valve during other time periods. The valve provides improved passage in the direction of flow and positive closure in the direction against the flow. The actuator is a dome shaped internally prestressed ferroelectric actuator having a curvature, said dome shaped actuator having a rim and an apex. and a dome height measured from a plane through said rim said apex that varies with an electric voltage applied between an inside and an outside surface of said dome shaped actuator.

  8. Fluid relief and check valve

    DOEpatents

    Blaedel, K.L.; Lord, S.C.; Murray, I.

    1986-07-17

    A passive fluid pressure relief and check valve allows the relief pressure to be slaved to a reference pressure independently of the exhaust pressure. The pressure relief valve is embodied by a submerged vent line in a sealing fluid, the relief pressure being a function of the submerged depth. A check valve is embodied by a vertical column of fluid (the maximum back pressure being a function of the height of the column of fluid). The pressure is vented into an exhaust system which keeps the exhaust out of the area providing the reference pressure.

  9. Electrically actuated well annulus safety valve

    SciTech Connect

    Pringle, R.E.; Morris, A.J.

    1993-07-27

    An electrically actuated well annulus safety valve is described for controlling fluid flow between a production string and a casing comprising, a housing having an inner bore and an outer passageway there through, passageway valve means connected to the housing for opening and closing the passageway, biasing means in the housing for biasing the valve means to the closed position, an armature secured to the valve means, a solenoid coil in the housing for attracting the armature for opening the passageway, an equalizing valve in the housing bypassing the passageway valve means, and electrically operated means in the housing for opening and closing the equalizing valve.

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

    PubMed

    Ramakrishna, Harish; DeValeria, Patrick A; Sweeney, John P; Mookaram, Farouk

    2015-01-01

    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. PMID:25849702

  11. Saving a Life: Heart Valve Replacement

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students use their knowledge about how healthy heart valves function to design, construct and implant prototype replacement mitral valves for hypothetical patients' hearts. Building on what they learned in the associated lesson about artificial heart valves, combined with the testing and scoring of their prototype heart valve designs in this activity, students discover the pros and cons of different types of artificial heart valves based on materials, surgery requirements, and lifespan.

  12. The effect of respiratory static volumes on heart valve sounds

    E-print Network

    Im, Jae Joong

    1988-01-01

    comparatively long, vibrating sound. It is the sound vena cava aorta pulmonary valve left atrium right atrium rtic valve tricuspid valve (AV valve) in s ~ 'L 4 D O a bicuspid valve (AV valve, mitral valve) right ventricle left ventricle Fig I...

  13. Delineation in thoracic oncology: a prospective study of the effect of training on contour variability and dosimetric consequences

    PubMed Central

    2011-01-01

    Introduction As part of French residents' radiotherapy training, delineation workstations were available at a national teaching course. We report a prospective comparative study of a non small cell lung cancer (NSCLC) case delineated by 120 residents before and after a radioanatomy/radiotherapy lecture. Materials and methods The case of a patient with right upper lobe non small cell lung cancer (NSCLC) was provided for delineation to 32 groups of residents before and after a radiation therapy lecture about thoracic delineation. GTV, CTV and PTV was asked to each group. In a second step, the GTV, CTV and PTV were compared with those of 9 groups of senior physicians. Finally the consequences for treatment planning between each group before and after the course were explored. Results The expert's average GTV, CTV and PTV were 89.1 cm3, 242.3 cm3 and 293.9 cm3 respectively. For residents, those volumes were 103.4 cm3, 242.3 cm3 and 457.9 cm3 before teaching, compared to 99.5 cm3, 224.2 cm3 and 412.5 cm3 after teaching. The overlap (OV) and kappa (KI) indices before and after education were respectively 0.58 and 0.73. Compared to senior physicians, OV and KI indices were lower in the residents group (p = 0.039 and p = 0.043). An increased dose to the lung is noted for the residents' dosimetry compared to the experts' (V20: 23.2% versus 36.5%) due to the larger PTV delineated. No significant difference was observed for other organs at risk. Conclusion There were no significant differences for the delineation of the GTV and CTV before and after the course, although the differences tended to decrease after the course. The good initial quality of the contours could explain the lack of difference. V20 for lung was higher in the residents group compared to the experts group (23.2% vs 36.5%). No other treatment planning consequences were observed for other critical organs. PMID:21929770

  14. Bipropellant shut-off valve

    NASA Technical Reports Server (NTRS)

    Smith, J. V.

    1971-01-01

    An advanced design of an all metal, fast response, bipropellant, shut-off valve for use on long duration space missions is reported. The valve provides the flow control capability for a 1,000 lb thrust, bipropellant engine using oxygen difluoride and diborane as propellants. The shutoff seal selection is a soft-on-hard metal concept. The soft seal is a spherical shell that seats against a hard conical seat. Beryllium copper and beryllium nickel seals were selected to seal against an electrolyzed Inconel 718 seat. Poppet shaft sealing is achieved by use of hydroformed, Inconel 718 bellows. Two valve assemblies were fabricated and subjected to a series of tests including leak, response time, flow capacity, dry cycles, water cycles, liquid nitrogen cycles, liquid fluorine cycles, and lead-lag operation cycles. These tests demonstrated the ability of the valve to meet design goals.

  15. Living with Mitral Valve Prolapse

    MedlinePLUS

    ... are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To ... Media Availability: Mitral valve repair following heart attack may offer ...

  16. Development of a fast valve for mitigating disruptions in tokamaks

    NASA Astrophysics Data System (ADS)

    Savtchkov, A.; Finken, K. H.; Mank, G.

    2002-10-01

    In support of our disruption mitigation profram, a fast gas valve has been constructed and tested on TEXTOR at FZJ Juelich. Its main features have been shown to be: (1) rapid response time: 0.5 ms; (2) amount of injected gas: variable, 2-1000 mbar×l; (3) linear dependence of the number of injected particles on the gas pressure; (4) capability of working in a strong magnetic field; (5) sort of gas: any. The valve has the standard CF 35 flange, commonly used in vacuum engineering. All the components that have contact with vacuum were made of stainless steel, except for the closing aluminum piston. To prevent gas leaking directly from the bottles to the experimental vessel there are also two safety valves, closing the bottles before the shot. The required control equipment includes a high power supply and the combined controller for the safety valves and baratrons, both being able to work with TTL control signals. During tests and experiments on TEXTOR and ASDEX-Upgrade, the valve showed successful operation with three gas types: He, Ne, Ar.

  17. Echocardiographic and phonocardiographic confirmation of suspected caged mitral valve malfunction.

    PubMed

    Berndt, T B; Goodman, D J; Popp, R L

    1976-08-01

    Seven patients studied by echocardiography with and without simultaneous phonocardiography for suspected malfunction of a caged mitral valve prosthesis are presented. In case 1, with inaudible prosthetic clicks, thrombosis of the cage and immobility of the ball were suggested by echocardiographic studies and confirmed at surgery. In case 2, simultaneous echocardiographic and phonocardiographic studies demonstrated wide and variable intervals between the aortic second sound the the opening click and also "sticking" of the ball. In case 3 a thrombus prevented full motion of the ball to the apex of the cage, which was seen on the echocardiogram, while in case 4, with a thrombus within the ventricle and prosthesis, the prosthetic opening click was present intermittently and was associated with only subtle echocardiographic changes. In case 5, echocardiographic studies demonstrated abnormal rocking of the cage secondary to severe prosthetic dehiscence. In case 6, dul prosthetic clicks were to be secondary to a low cardiac-output state. In case 7, with multiple valve prostheses, simultaneous echocardiographic and phonocardiographic studies allowed identification of individual valve sounds and abnormal timing of valve opening. Based on these studies, we believe that echocardiography and simultaneous phonocardiography can yield very useful information in the evaluation of patients with suspected malfunction of a caged mitral valve prosthesis. PMID:947687

  18. Midterm results of aortic valve repair with the pericardial cusp extension technique in rheumatic valve disease

    Microsoft Academic Search

    Nilgün Bozbuga; Vedat Erentug; Kaan Kirali; Esat Akinci; Ömer Isik; Cevat Yakut

    2004-01-01

    BackgroundThe encouraging results of valve repair in the atrioventricular valves have influenced a decision about aortic valve (AV) reconstruction. We report our experience with pericardial cusp extension to repair rheumatic AV disease.

  19. Petroleum well tubing safety valve

    Microsoft Academic Search

    Holbert; M. L. Jr

    1973-01-01

    Preferably installed in a socket in the wellhead, this flapper-type check valve incorporates a differential pressure-operated piston as an opening and closing sleeve. The valve may be economically installed in existing wells, e.g., offshore dual wells on multiple well platforms to provide internal blowout and anti-fire protection for wells which presently have no other positive closure than, e.g., a storm

  20. Reoperation on prosthetic heart valves

    Microsoft Academic Search

    Jeffrey M. Piehler; Eugene H. Blackstone; Kent R. Bailey; Michael E. Sullivan; James R. Pluth; Noel S. Weiss; Ron S. Brookmeyer; James G. Chandler

    1995-01-01

    Reoperation on prosthetic heart valves is increasingly under consideration for both clinical and prophylactic indications. To determine the correlates of hospital events, including in-hospital mortality, new persisting neurologic deficit, and length of postoperative stay, a three-institution study of 2246 consecutive prosthetic valve reoperations performed on 1984 patients between 1963 and 1992 was undertaken. The combined experience ranged from high-risk patients

  1. Prosthetic valve endocarditis. A survey.

    PubMed

    Ben Ismail, M; Hannachi, N; Abid, F; Kaabar, Z; Rougé, J F

    1987-07-01

    Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in four with both aortic and mitral prosthetic valves. Streptococci were the most commonly isolated microorganisms, followed by staphylococci, Gram negative bacteria, and fungi. A surgical (34 cases) or a necropsy specimen (10 cases) from 44 cases was examined. Eighty two per cent of the patients had congestive heart failure. Twenty four of the 58 patients were medically treated and 17 died (70% mortality). Combined medical and surgical treatment was used in 34 patients; the main indication for surgery was congestive heart failure. Fourteen patients on combined treatment died (40% mortality). Persistent sepsis and prosthetic valve dehiscence were the most common early and late operative complications. The most important influences on outcome were congestive heart failure, the type of micro-organism, the severity and extent of anatomical lesions, the time of onset of prosthetic valve endocarditis, and the type of treatment. This survey indicates that only patients without congestive heart failure or embolic complications and with sensitive micro-organism should be treated medically. In view of the poor prognosis patients with prosthetic valve endocarditis associated with congestive heart failure, persistent sepsis, and repeat arterial emboli should be treated by early surgical intervention. PMID:3620246

  2. Prosthetic valve endocarditis. A survey.

    PubMed Central

    Ben Ismail, M; Hannachi, N; Abid, F; Kaabar, Z; Rougé, J F

    1987-01-01

    Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in four with both aortic and mitral prosthetic valves. Streptococci were the most commonly isolated microorganisms, followed by staphylococci, Gram negative bacteria, and fungi. A surgical (34 cases) or a necropsy specimen (10 cases) from 44 cases was examined. Eighty two per cent of the patients had congestive heart failure. Twenty four of the 58 patients were medically treated and 17 died (70% mortality). Combined medical and surgical treatment was used in 34 patients; the main indication for surgery was congestive heart failure. Fourteen patients on combined treatment died (40% mortality). Persistent sepsis and prosthetic valve dehiscence were the most common early and late operative complications. The most important influences on outcome were congestive heart failure, the type of micro-organism, the severity and extent of anatomical lesions, the time of onset of prosthetic valve endocarditis, and the type of treatment. This survey indicates that only patients without congestive heart failure or embolic complications and with sensitive micro-organism should be treated medically. In view of the poor prognosis patients with prosthetic valve endocarditis associated with congestive heart failure, persistent sepsis, and repeat arterial emboli should be treated by early surgical intervention. PMID:3620246

  3. Liquid-blocking check valve

    DOEpatents

    Merrill, J.T.

    1982-09-27

    A liquid blocking check valve useful particularly in a pneumatic system utilizing a pressurized liquid fill chamber. The valve includes a floatable ball disposed within a housing defining a chamber. The housing is provided with an inlet aperture disposed in the top of said chamber, and an outlet aperture disposed in the bottom of said chamber in an offset relation to said inlet aperture and in communication with a cutaway side wall section of said housing.

  4. Periostin regulates atrioventricular valve maturation.

    PubMed

    Norris, Russell A; Moreno-Rodriguez, Ricardo A; Sugi, Yukiko; Hoffman, Stanley; Amos, Jenny; Hart, Mary M; Potts, Jay D; Goodwin, Richard L; Markwald, Roger R

    2008-04-15

    Cardiac valve leaflets develop from rudimentary structures termed endocardial cushions. These pre-valve tissues arise from a complex interplay of signals between the myocardium and endocardium whereby secreted cues induce the endothelial cells to transform into migratory mesenchyme through an endothelial to mesenchymal transformation (EMT). Even though much is currently known regarding the initial EMT process, the mechanisms by which these undifferentiated cushion mesenchymal tissues are remodeled "post-EMT" into mature fibrous valve leaflets remains one of the major, unsolved questions in heart development. Expression analyses, presented in this report, demonstrate that periostin, a component of the extracellular matrix, is predominantly expressed in post-EMT valve tissues and their supporting apparatus from embryonic to adult life. Analyses of periostin gene targeted mice demonstrate that it is within these regions that significant defects are observed. Periostin null mice exhibit atrial septal defects, structural abnormalities of the AV valves and their supporting tensile apparatus, and aberrant differentiation of AV cushion mesenchyme. Rescue experiments further demonstrate that periostin functions as a hierarchical molecular switch that can promote the differentiation of mesenchymal cells into a fibroblastic lineage while repressing their transformation into other mesodermal cell lineages (e.g. myocytes). This is the first report of an extracellular matrix protein directly regulating post-EMT AV valve differentiation, a process foundational and indispensable for the morphogenesis of a cushion into a leaflet. PMID:18313657

  5. Effects of aerobic exercise training and irbesartan on blood pressure and heart rate variability in patients with chronic obstructive pulmonary disease

    PubMed Central

    Marquis, Karine; Maltais, François; Lacasse, Yves; Lacourcière, Yves; Fortin, Claudette; Poirier, Paul

    2008-01-01

    BACKGROUND AND OBJECTIVES: The present pilot study was undertaken to evaluate the efficacy of an aerobic exercise training (AET) program alone or combined with an antihypertensive agent (irbesartan) to reduce blood pressure (BP) and enhance heart rate variability (HRV) in chronic obstructive pulmonary disease patients. METHODS: Twenty-one patients were randomly assigned to a double-blind treatment with exercise and placebo (n=11) or exercise and irbesartan (n=10). Subjects underwent 24 h BP monitoring and 24 h electrocardiographic recording before and after the 12-week AET. HRV was investigated using three indexes from the power spectral analysis and three indexes calculated from the time domain. The AET program consisted of exercising on a calibrated ergocycle for 30 min three times per week. Five patients in the placebo group were excluded during follow-up because they were not compliant. RESULTS: There was no change in 24 h systolic and diastolic BP before (130±14 mmHg and 70±3 mmHg, respectively) and after (128±8 mmHg and 70±8 mmHg, respectively) exercise training in the placebo group, whereas in the irbesartan group systolic and diastolic BP decreased from 135±9 mmHg and 76±9 mmHg to 126±12 mmHg and 72±8 mmHg, respectively (P<0.02). There were no changes in HRV parameters in either group. CONCLUSIONS: The present study suggests that a 12-week AET program is not associated with a significant reduction in BP or enhancement in HRV, whereas an AET program combined with irbe-sartan is associated with a reduction in 24 h BP. PMID:18949104

  6. 46 CFR 160.151-39 - Training of servicing technicians.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...certification of servicing technicians must include— (1) Training and practice in packing an inflatable liferaft, repairing buoyancy tubes, repairing inflation-system valves, and other inspections and operations described in the approved servicing...

  7. 46 CFR 160.151-39 - Training of servicing technicians.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...certification of servicing technicians must include— (1) Training and practice in packing an inflatable liferaft, repairing buoyancy tubes, repairing inflation-system valves, and other inspections and operations described in the approved servicing...

  8. 46 CFR 160.151-39 - Training of servicing technicians.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...certification of servicing technicians must include— (1) Training and practice in packing an inflatable liferaft, repairing buoyancy tubes, repairing inflation-system valves, and other inspections and operations described in the approved servicing...

  9. Extension of Robust Design of Unstable Valve: Diagonally Structured Uncertainty QingHui Yuan , Perry Y. Li

    E-print Network

    Li, Perry Y.

    a useful strategy: among multiple scalars, each time we just treat one of them as a variable requiringExtension of Robust Design of Unstable Valve: Diagonally Structured Uncertainty QingHui Yuan , Perry Y. Li Abstract-- A robust design of an unstable valve with diag- onally structured uncertainty

  10. Annular flow diverter valve

    DOEpatents

    Rider, Robert L. (Walkersville, MD)

    1980-01-01

    A valve for diverting flow from the center of two concentric tubes to the annulus between the tubes or, operating in the reverse direction, for mixing fluids from concentric tubes into a common tube and for controlling the volume ratio of said flow consists of a toroidal baffle disposed in sliding engagement with the interior of the inner tube downstream of a plurality of ports in the inner tube, a plurality of gates in sliding engagement with the interior of the inner tube attached to the baffle for movement therewith, a servomotor having a bullet-shaped plug on the downstream end thereof, and drive rods connecting the servomotor to the toroidal baffle, the servomotor thereby being adapted to move the baffle into mating engagement with the bullet-shaped plug and simultaneously move the gates away from the ports in the inner tube and to move the baffle away from the bullet-shaped plug and simultaneously move the gates to cover the ports in the inner tube.

  11. Abrasion resistant valves cut platform maintenance cost

    SciTech Connect

    NONE

    1997-02-01

    Shell Exploration and Production, operator of Brent field in the UK North Sea, turned to Anglo-US valve maker Serck Audco Valves for help in solving persistent valve maintenance problems. Brent Charlie platform was selected as a test site for the supplier`s new line of abrasion-resistant valves. The most common failure cause is abrasion by solids in the line fluid, particularly sand, which damages even stainless steel and Duplex valve seats, creating leak paths which prevent valve sealing. Serck Audco manufacturers the Super-H all-metal pressure-balanced plug valve, which has proved particularly resistant to erosion in some of the world`s harshest operating environments. The paper describes the valve`s extra abrasion resistance and the Brent Charlie test.

  12. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

    1993-03-16

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  13. Automatic control apparatus for engine throttle valve

    SciTech Connect

    Ejiri, Y.; Ito, T.

    1988-04-05

    An automatic control apparatus for an engine throttle valve is described, consisting of a throttle valve and a motor for driving the throttle valve. The improvement comprises means for opening the throttle valve forcedly from a full-close position at the time of engine shutdown so as not to allow a tar component in the fuel for driving the engine to stick on the throttle valve at an outer peripheral portion. The situation on whether or not the engine is shut down is detected according to rotations of an engine output shaft, thereby driving the means for opening the valve forcedly.

  14. Valve system incorporating single failure protection logic

    DOEpatents

    Ryan, Rodger (San Jose, CA); Timmerman, Walter J. H. (Saratoga, CA)

    1980-01-01

    A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

  15. Variable force solenoid pressure control for an automatic transmission

    Microsoft Academic Search

    Lemieux

    1989-01-01

    This patent describes a hydraulic pressure control circuit for an automatic transmission having fluid pressure operated clutch and brake servo. The controlling transmission consists of: a pump and a main pressure regulator valve means for establishing a regulated pressure in the control circuit; a variable force solenoid valve means for developing a pressure proportional to engine torque including a variable

  16. Light valve based on nonimaging optics with potential application in cold climate greenhouses

    NASA Astrophysics Data System (ADS)

    Valerio, Angel A.; Mossman, Michele A.; Whitehead, Lorne A.

    2014-09-01

    We have evaluated a new concept for a variable light valve and thermal insulation system based on nonimaging optics. The system incorporates compound parabolic concentrators and can readily be switched between an open highly light transmissive state and a closed highly thermally insulating state. This variable light valve makes the transition between high thermal insulation and efficient light transmittance practical and may be useful in plant growth environments to provide both adequate sunlight illumination and thermal insulation as needed. We have measured light transmittance values exceeding 80% for the light valve design and achieved thermal insulation values substantially exceeding those of traditional energy efficient windows. The light valve system presented in this paper represents a potential solution for greenhouse food production in locations where greenhouses are not feasible economically due to high heating cost.

  17. An electromechanical valve drive incorporating a nonlinear mechanical transformer

    E-print Network

    Chang, Woo Sok, 1964-

    2003-01-01

    In traditional internal combustion engines, a camshaft acts on the valve stems to open and close the valves. Valve timing is fixed relative to piston position. On the other hand, if a valve is flexibly controlled by a ...

  18. 21 CFR 868.1965 - Switching valve (ploss).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Switching valve (ploss). (a) Identification. A switching valve (ploss) is a three-way valve located between a stethoscope placed over the heart, a blood pressure cuff, and an earpiece. The valve allows the user to eliminate one sound...

  19. 21 CFR 868.1965 - Switching valve (ploss).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Switching valve (ploss). (a) Identification. A switching valve (ploss) is a three-way valve located between a stethoscope placed over the heart, a blood pressure cuff, and an earpiece. The valve allows the user to eliminate one sound...

  20. 21 CFR 868.1965 - Switching valve (ploss).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Switching valve (ploss). (a) Identification. A switching valve (ploss) is a three-way valve located between a stethoscope placed over the heart, a blood pressure cuff, and an earpiece. The valve allows the user to eliminate one sound...