Sample records for variable valve train

  1. Variable orifice gas modulating valve

    Microsoft Academic Search

    1993-01-01

    An automatic gas modulating valve is described for regulating the flow of gaseous fuel from a fuel source to a gas burner, comprising a first valve body member; a second valve body member fixed to the first valve body member so as to define a relatively thin planar slide cavity between the first valve body member and the second valve

  2. 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.

  3. OPTIMIZATION OF AUTOMOTIVE VALVE TRAIN COMPONENTS WITH IMPLICT FILTERING \\Lambda

    E-print Network

    in this application. In x 3 we present the details of the valve train model and the optimization problems to be solvedOPTIMIZATION OF AUTOMOTIVE VALVE TRAIN COMPONENTS WITH IMPLICT FILTERING \\Lambda T. D. CHOI y , O identification and optimization in automotive valve train design. We extend our previous work by using a more

  4. 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.

  5. OPTIMIZATION OF AUTOMOTIVE VALVE TRAIN COMPONENTS WITH IMPLICT , O. J. ELSINGER

    E-print Network

    OPTIMIZATION OF AUTOMOTIVE VALVE TRAIN COMPONENTS WITH IMPLICT FILTERING T. D. CHOI ¡ , O. J and optimization in automotive valve train design. We extend our previous work by using a more refined model of the valve train and exploiting parallelism in a new way. We apply the parameter identification results

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

    E-print Network

    Developing a Training Tool for Intraoperative Mitral Valve Analysis Neil A. Tenenholtz, Robert D@seas.harvard.edu INTRODUCTION The mitral valve is one of the four valves of the human heart. Serving as a passive check valve transparency. To produce such a fast simulation, a mass-spring approximation of a finite element model

  7. Variable reluctance proximity sensors for cryogenic valve position indication

    NASA Technical Reports Server (NTRS)

    Cloyd, R. A.

    1982-01-01

    A test was conducted to determine the performance of a variable reluctance proximity sensor system when installed in a space shuttle external tank vent/relief valve. The sensors were used as position indicators. The valve and sensors were cycled through a series of thermal transients; while the valve was being opened and closed pneumatically, the sensor's performance was being monitored. During these thermal transients, the vent valve was cooled ten times by liquid nitrogen and two times by liquid hydrogen. It was concluded that the sensors were acceptable replacements for the existing mechanical switches. However, the sensors need a mechanical override for the target similar to what is presently used with the mechanical switches. This override could insure contact between sensor and target and eliminate any problems of actuation gap growth caused by thermal gradients.

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

    NASA Astrophysics Data System (ADS)

    Cross, Paul C.; Hansen, Craig N.

    1994-11-01

    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, and overhaul accessibility. Additionally, use of the variable valve timing capability to vary the effective compression ratio is expected to improve multifuel 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.

  9. Heart rate variability of children with mitral valve prolapse

    Microsoft Academic Search

    Lin Han; Ting Fei Ho; William CL Yip; Kit Yee Chan

    2000-01-01

    Studies have indicated that adult patients with mitral valve prolapse (MVP) may have autonomic dysfunction. The purpose of this study was to evaluate heart rate variability (HRV) in children with MVP. Sixty-seven children with MVP (ages 6 to 18 years; 30 boys and 37 girls) were consecutively studied and subdivided into those with or without symptoms. Thirty-seven normal age-matched children

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

    E-print Network

    Najjar, Walid A.

    VALVE: Variable Length Value Encoder for Off-Chip Data Buses. Dinesh C. Suresh, Banit Agrawal (VALVE) technique to reduce the power consumption in the off-chip data buses. While past research has proposed scheme is capable of detecting and encoding variable length bit patterns in the data values. VALVE

  11. 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.

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

    SciTech Connect

    Shibayama, T.; Sugano, K.

    1986-12-30

    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 regulator valve is described for regulating the output of the pump by draining off some of the fluid discharged by the pump and developing a control pressure, the regulator valve including a bore formed with: a first port which receives the output of the pump, a second port which fluidly communicates with the control chamber, and a drain port, the regulator valve further including a spool which is reciprocatively disposed in the bore and which is formed with first and second lands. The first land defines a first variable orifice between the first and second ports and the second land defining a second variable orifice between the second and drain ports; and a fixed flow restriction within the bore, for restricting fluid communication between the first and second ports and the second and drain ports. The fixed flow restriction is defined between the wall of the bore and a first portion of the spool which extends between the first and second lands. The portion has a diameter which is selected with respect to the diameter of that portion of the bore in which it is disposed so as to define a gap having a maximum width of 1.5 mm.

  13. 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

  14. 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.

  15. Valve

    DOEpatents

    Cho, Nakwon (Knoxville, TN)

    1980-01-01

    A positive acting valve suitable for operation in a corrosive environment is provided. The valve includes a hollow valve body defining an open-ended bore for receiving two, axially aligned, spaced-apart, cylindrical inserts. One insert, designated the seat insert, terminates inside the valve body in an annular face which lies within plane normal to the axis of the two inserts. An elastomeric O-ring seal is disposed in a groove extending about the annular face. The other insert, designated the wedge insert, terminates inside the valve body in at least two surfaces oppositely inclined with respect to each other and with respect to a plane normal to the axis of the two inserts. An elongated reciprocable gate, movable between the two inserts along a path normal to the axis of the two inserts, has a first flat face portion disposed adjacent and parallel to the annular face of the seat insert. The gate has a second face portion opposite to the first face portion provided with at least two oppositely inclined surfaces for mating with respective inclined surfaces of the wedge insert. An opening is provided through the gate which registers with a flow passage through the two inserts when the valve is open. Interaction of the respective inclined surfaces of the gate and wedge insert act to force the first flat face portion of the gate against the O-ring seal in the seat insert at the limits of gate displacement where it reaches its respective fully open and fully closed positions.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The paper discusses advantages provided by electronically controlled hydraulically activated valves (ECVs) when applied to low heat rejection (LHR) engines. The ECV concept provides additional engine control flexibility by allowing for a variable valve timing as a function of speed and load, or for a given transient condition. The results of a study carried out to assess the benefits that this flexibility can offer to an LHR engine indicated that, when judged on the benefits to BSFC, volumetric efficiency, and peak firing pressure, ECVs would provide only modest benefits in comparison to conventional valve profiles. It is noted, however, that once installed on the engine, the ECVs would permit a whole range of certain more sophisticated variable valve timing strategies not otherwise possible, such as high compression cranking, engine braking, cylinder cutouts, and volumetric efficiency timing with engine speed.

  17. Control valve system for a continuously variable belt driven transmission for motor vehicles

    Microsoft Academic Search

    U. Eggert; H. Staffel

    1988-01-01

    This patient describes a hydraulic valve system for controlling a continuously variable drive ratio automotive vehicle transmission adapted to shift continuously between different drive ratios and having first and second control pulleys driveably connected by an endless traction belt, a displacement cylinder associated with each pulley, the location of the belt on each pulley being radially variable in response to

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

    SciTech Connect

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

    1995-12-12

    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. 21 figs.

  19. 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.

  20. Output feedback Parametric Controllers for an Active Valve Train Actuation System

    Microsoft Academic Search

    V. Kosmidis; A. Panga; V. Sakizlis; G. Charles; S. Kenchington; N. Bozinis; E. N. Pistikopoulos

    2006-01-01

    The first commercial camless car engines featuring continuously variable valve timing are expected to be available by 2010 to meet the strict legislation on NOx and COx emissions. A key factor for the development of this technology is the design of controllers that can maintain accurate signal tracking in the presence of variations in engine parameters and running conditions. Towards

  1. Management of bronchopleural fistula with a variable-resistance valve and a single ventilator.

    PubMed

    Carvalho, P; Thompson, W H; Riggs, R; Carvalho, C; Charan, N B

    1997-05-01

    Independent lung ventilation with two ventilators is sometimes used in the management of bronchopleural fistula (BPF). We describe a patient in whom gas flow through a large BPF was initially reduced, and subsequently eliminated, during differential lung ventilation using a single ventilator and a variable-resistance valve attached to one lumen of a bifurcated endotracheal tube. PMID:9149613

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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…

  7. Fault diagnosis for diesel valve trains based on non-negative matrix factorization and neural network ensemble

    NASA Astrophysics Data System (ADS)

    Qinghua, Wang; Youyun, Zhang; Lei, Cai; Yongsheng, Zhu

    2009-07-01

    It is well known that the vibration signals are unstable when there is some failure in machinery. So in this paper, the cone-shaped kernel distributions (CKD) of vibration acceleration signals acquired from the cylinder head in eight different states of valve train were calculated and displayed in grey images. Meanwhile, non-negative matrix factorization (NMF) was used to decompose multivariate data, and neural network ensemble (NNE), which is of better generalization capability for classification than a single neural network, was used to perform intelligent diagnosis without further fault feature (such as eigenvalues or symptom parameters) extraction from time-frequency distributions. It is shown by the experimental results that the faults of diesel valve trains can be accurately classified by the proposed method.

  8. Variable resistance training promotes greater fatigue resistance but not hypertrophy versus constant resistance training.

    PubMed

    Walker, Simon; Hulmi, Juha J; Wernbom, Mathias; Nyman, Kai; Kraemer, William J; Ahtiainen, Juha P; Häkkinen, Keijo

    2013-09-01

    Loading using variable resistance devices, where the external resistance changes in line with the force:angle relationship, has been shown to cause greater acute neuromuscular fatigue and larger serum hormone responses. This may indicate a greater potential for adaptation during long-term training. Twelve (constant resistance group) and 11 (variable resistance group) men completed 20 weeks of resistance training with 10 men as non-training controls. Training-induced adaptations were assessed by bilateral leg press one repetition maximum, a repetition to failure test using 75 % 1RM, lower limb lean mass and vastus lateralis cross-sectional area. Only the variable resistance training group improved the total number of repetitions (41 ± 46 %) and volume load (52 ± 37 %) during the repetition to failure test (P < 0.05). Similar improvements in maximum strength and hypertrophy of the lower limbs were observed in both training groups. Also, constant and variable resistance 5 × 10RM leg press loadings were performed before and after training in a crossover design. Acute loading-induced responses were assessed by concentric and isometric force, serum hormone concentrations and phosphorylation of intramuscular signalling proteins (0-30 min post-loading). Greater acute decreases in force (P < 0.05-0.01), and greater increases in serum testosterone and cortisol concentration (P < 0.05) and ERK 1/2 phosphorylation (P < 0.05) were observed following variable resistance loadings before and after training. Greater training-induced improvements in fatigue resistance occurred in the variable resistance training group, which may be due to greater acute fatigue and physiological responses during variable versus constant resistance loadings. PMID:23636698

  9. 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

  10. 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.

  11. Heart rate variability is related to training load variables in interval running exercises

    Microsoft Academic Search

    Piia Kaikkonen; Esa Hynynen; Theresa Mann; Heikki Rusko; Ari Nummela

    Overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues,\\u000a organs and\\/or body. However, there is no “golden standard” for TL measurement. The aim of the present study was to investigate\\u000a if post-exercise heart rate variability (HRV) could be used to evaluate TL of interval running exercises with different intensities\\u000a and

  12. Aortic Valve

    MedlinePLUS

    ... Replacement of Artificial Valves? Are There Differences Between Mechanical and Biological Replacement Valves? Why is Surgery Necessary? ... are two types of artificial valves or prostheses: mechanical valves and biological valves . Examples of the valves ...

  13. Changes of Serum ?-Endorphin by Programmed Exercise Training Are Correlated with Improvement of Clinical Symptoms and Quality of Life in Female Mitral Valve Prolapse Syndrome

    Microsoft Academic Search

    Huei-Fong Hung; Pai-Feng Kao; Yu-Shuang Lin; Feng-Chia Chen; Fu-Chean Chen; Jen-Chen Tsai; Paul Chan

    2007-01-01

    Background: Mitral valve prolapse (MVP) is a common entity in female population. Although this is a minor disease, it may cause annoying symptoms that impair quality of life (QOL), and no established therapy for this problem. The aim of this study isto examine whether programmed exercise training by treadmill in female MVP syndrome would improve clinical symptoms and QOL. Methods:

  14. 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

  15. Exercise Training Improves Heart Rate Variability after Methamphetamine Dependency

    PubMed Central

    Dolezal, Brett A.; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A.; Garfinkel, Alan; Cooper, Christopher B.

    2014-01-01

    Purpose Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent MD participants with age-matched, drug free controls (DF) and also investigated whether HRV can be improved with exercise training in the MD participants. Methods In 50 participants (MD=28; DF=22) resting heart rate (R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time-domain (SDNN, RMSSD, pNN50) and frequency-domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice weekly exercise training (ME=14) or equal attention without training (MC=14) over 8 weeks. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P?0.05. Results Participant characteristics were matched between groups: age 33±6 years; body mass 82.7±12 kg, BMI 26.8±4.1 kg•min?2, mean±SD. Compared with DF, the MD group had significantly higher resting heart rate (P<0.05), LFnu, and LF/HF (P<0.001) as well as lower SDNN, RMSSD, pNN50 and HFnu (all P<0.001). At randomization, HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P<0.001) increased SDNN (+14.7±2.0 ms, +34%), RMSSD (+19.6±4.2 ms, +63%), pNN50 (+22.6±2.7%, +173%), HFnu (+14.2±1.9, +60%) and decreased HR (?5.2±1.1 beats·min?1, ?7%), LFnu (?9.6±1.5, ?16%) and LF/HF (?0.7±0.3, ?19%). These measures did not change from baseline in the MC group. Conclusion HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine dependent individuals. Moreover, physical training yielded a marked increase of HRV representing increased vagal modulation or improved autonomic balance. PMID:24162556

  16. 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…

  17. 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.

  18. 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

  19. Variable Effects of Physical Training of Heart Rate Variability, Heart Rate Recovery, and Heart Rate Turbulence in Chronic Heart Failure

    Microsoft Academic Search

    EWA PIOTROWICZ; RAFA? BARANOWSKI; MA?GORZATA PIOTROWSKA; TOMASZ ZIELI?SKI; RYSZARD PIOTROWICZ

    2009-01-01

    Background: Heart rate variability (HRV), heart rate turbulence (HRT), and heart rate recovery (HRR), indices that reflect autonomic nervous system (ANS) activity, are outcome predictors in patients with chronic heart failure (CHF). It is not clear, however, whether they reflect the same components of ANS activity. No study has examined the effects of physical training (PT) training on HRV, HRT,

  20. A novel power splitting drive train for variable speed wind power generators

    Microsoft Academic Search

    Xueyong Zhao; Peter Maißer

    2003-01-01

    In this paper a novel electrically controlled power splitting drive train for variable speed wind turbines is presented. A variable speed wind turbine has many advantages, mainly it can increase the power yield from the wind, alleviate the load peak in the electrical-mechanical drive train, and posses a long life time, also, it can offer the possibility to store the

  1. Safety valve

    DOEpatents

    Bergman, Ulf C. (Malmoe, SE)

    1984-01-01

    The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

  2. 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

  3. Training and Development: An Examination of Definitions and Dependent Variables

    ERIC Educational Resources Information Center

    Somasundaram, Usha Valli; Egan, Toby Marshall

    2004-01-01

    We explore training and development through the lenses of scholars and practitioners who have provided definitions and frameworks for exploring this area which is essential to human resource development (HRD). Thirty-five definitions of training and development are identified and analyzed. Themes from the analysis are explored, conclusions…

  4. 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

  5. Training and recovery behaviors of exchange bias in FeNi/Cu/Co/FeMn spin valves at high field sweep rates

    NASA Astrophysics Data System (ADS)

    Yang, D. Z.; Kapelrud, A.; Saxegaard, M.; Wahlström, E.

    2012-09-01

    Training and recovery of exchange bias in FeNi/Cu/Co/FeMn spin valves have been studied by magnetoresistance curves with field sweep rates from 1000 to 4800 Oe/s. It is found that training and recovery of exchange field are proportional to the logarithm of the training cycles and recovery time, respectively. These behaviors are explained within the model based on thermal activation. For the field sweep rates of 1000, 2000 and 4000 Oe/s, the relaxation time of antiferromagnet spins are 61.4, 27.6, and 11.5 in the unit of ms, respectively, much shorter than the long relaxation time (?102 s) in conventional magnetometry measurements.

  6. Low friction servo valve

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1968-01-01

    Valve was developed using air bearings which provide frictionless operation. The servo valve is of the flat plate type with rectangular meter openings. Fluid bearings support the metering plate. The overlap is adjustable by means of a variable hinge block support.

  7. Intelligent Flow Control Valve

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R (Inventor)

    2015-01-01

    The present invention is an intelligent flow control valve which may be inserted into the flow coming out of a pipe and activated to provide a method to stop, measure, and meter flow coming from the open or possibly broken pipe. The intelligent flow control valve may be used to stop the flow while repairs are made. Once repairs have been made, the valve may be removed or used as a control valve to meter the amount of flow from inside the pipe. With the addition of instrumentation, the valve may also be used as a variable area flow meter and flow controller programmed based upon flowing conditions. With robotic additions, the valve may be configured to crawl into a desired pipe location, anchor itself, and activate flow control or metering remotely.

  8. Percutaneous balloon dilatation of the mitral valve: an analysis of echocardiographic variables related to outcome and the mechanism of dilatation

    Microsoft Academic Search

    G T Wilkins; A E Weyman; V M Abascal; P C Block; I F Palacios

    1988-01-01

    Twenty two patients (four men, 18 women, mean age 56 years, range 21 to 88 years) with a history of rheumatic mitral stenosis were studied by cross sectional echocardiography before and after balloon dilatation of the mitral valve. The appearance of the mitral valve on the pre-dilatation echocardiogram was scored for leaflet mobility, leaflet thickening, subvalvar thickening, and calcification. Mitral

  9. 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

  10. Valve Disease

    MedlinePLUS

    ... a prosthetic valve. Prosthetic valves can either be mechanical (made from materials such as plastic, carbon, or ... or biological (made from human or animal tissue). Mechanical valves increase the risk of blood clots forming ...

  11. Training artificial neural networks using variable precision incremental communication

    Microsoft Academic Search

    Ali A. Ghorbani; Virendra C. Bhavsar

    1994-01-01

    We have earlier proposed incremental inter-node communication to reduce the communication cost as well as time of the learning process in artificial neural networks. In the incremental communication, instead of communicating the full magnitude of an input (output) variable of a neuron, only the increment\\/decrement to the previous value of the variable, using reduced precision, is sent on a communication

  12. 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…

  13. On the Spike Train Variability Characterized by Variance-to-Mean Power Relationship.

    PubMed

    Koyama, Shinsuke

    2015-07-01

    We propose a statistical method for modeling the non-Poisson variability of spike trains observed in a wide range of brain regions. Central to our approach is the assumption that the variance and the mean of interspike intervals are related by a power function characterized by two parameters: the scale factor and exponent. It is shown that this single assumption allows the variability of spike trains to have an arbitrary scale and various dependencies on the firing rate in the spike count statistics, as well as in the interval statistics, depending on the two parameters of the power function. We also propose a statistical model for spike trains that exhibits the variance-to-mean power relationship. Based on this, a maximum likelihood method is developed for inferring the parameters from rate-modulated spike trains. The proposed method is illustrated on simulated and experimental spike trains. PMID:25973546

  14. 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…

  15. Highly Variable Spike Trains Underlie Reproducible Sensorimotor Responses in the Medicinal Leech

    E-print Network

    Zoccolan, Davide

    Highly Variable Spike Trains Underlie Reproducible Sensorimotor Responses in the Medicinal Leech and Istituto Nazionale di Fisica della Materia, 34014 Trieste, Italy The nervous system of the leech mechanical stimulation of the leech skin. We analyzed variability at different levels of processing

  16. Effect of yogic training on physiological variables in working women.

    PubMed

    Kurwale, Manisha V; Gadkari, Jayeshree V

    2014-01-01

    Depression and anxiety in women sharply rising. Working women have high level of stress than non working women. Increasing amount of work stress at home and work place and its impact on family and home environment can be seen, which affect their emotional, psychological and physical health. The concept of yoga is helpful for reducing anxiety and improving cardiorespiratory parameters has created a great interest in the medical research field. The present study was conducted to assessing the effect of yogic exercises and meditation in working women. Yogic session was carried out for 16 weeks. Cardiorespiratory parameters (pulse rate, respiratory rate, blood pressure and breath holding time) were measured before and after yoga training. Stress was measured by anxiety score as an indicator of stress, also Visual reaction time as an indicator of cognitive function and finger dexterity score as an indicator of motor skills were measured before and after yoga training. Statistical analysis was done by paired 't' test. It was found that statistically significant improvement in cardiorespiratory parameters, anxiety score, visual reaction time and finger dexterity score (P < 0.05) after yogic training. Thus, a combined practice of asana, breathing exercises, and meditation & relaxation technique in a sequence is the best available resource to meet the.present day needs of society. PMID:25906618

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

    SciTech Connect

    Patterson, D.; Simko, A.; Reilly, D.

    1997-05-19

    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. As a base, a 4-valve, V-6 engine of 3.5 liters was used with a 3750 lb. passenger vehicle. The VVT system applied to that engine was a combination of the Atsugi cam phasing system, a modified Mitsubishi MIVEC long and short duration cam system and intake port throttle. The final VVT engine was presumed to have reduced idle speed (500 vs 640 rpm base) and an 8% lower displacement (3.22 liters).

  18. 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.…

  19. Prediction of space sickness in astronauts from preflight fluid, electrolyte, and cardiovascular variables and Weightless Environmental Training Facility (WETF) training

    NASA Technical Reports Server (NTRS)

    Simanonok, K.; Mosely, E.; Charles, J.

    1992-01-01

    Nine preflight variables related to fluid, electrolyte, and cardiovascular status from 64 first-time Shuttle crewmembers were differentially weighted by discrimination analysis to predict the incidence and severity of each crewmember's space sickness as rated by NASA flight surgeons. The nine variables are serum uric acid, red cell count, environmental temperature at the launch site, serum phosphate, urine osmolality, serum thyroxine, sitting systolic blood pressure, calculated blood volume, and serum chloride. Using two methods of cross-validation on the original samples (jackknife and a stratefied random subsample), these variables enable the prediction of space sickness incidence (NONE or SICK) with 80 percent sickness and space severity (NONE, MILD, MODERATE, of SEVERE) with 59 percent success by one method of cross-validation and 67 percent by another method. Addition of a tenth variable, hours spent in the Weightlessness Environment Training Facility (WETF) did not improve the prediction of space sickness incidences but did improve the prediction of space sickness severity to 66 percent success by the first method of cross-validation of original samples and to 71 percent by the second method. Results to date suggest the presence of predisposing physiologic factors to space sickness that implicate fluid shift etiology. The data also suggest that prior exposure to fluid shift during WETF training may produce some circulatory pre-adaption to fluid shifts in weightlessness that results in a reduction of space sickness severity.

  20. 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.

  1. Aortic Valve

    MedlinePLUS

    ... disease requiring surgery is called " senile aortic calcification ," meaning that the valve has worn out with age. ... valve of the left side of the heart, meaning that it opens during systole (when the ventricle ...

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

    PubMed Central

    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

  3. Neural Network-Based Noise Suppressor and Predictor for Quantifying Valve Stiction in Oscillatory Control Loops

    E-print Network

    Annan, Carl Ashie

    2014-12-18

    (fd) friction in a physical valve model. Each simulation generates controller output OP(t) and process variable PV(t) time series data. A feed-forward neural network (the predictor) is trained to model the relationship between a given OP and PV pattern...

  4. 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

  5. Instrumental Variables Estimates of the Effect of Subsidized Training on the Quantiles of Trainee Earnings

    Microsoft Academic Search

    Alberto Abadie; Joshua Angrist; Guido Imbens

    2002-01-01

    This paper reports estimates of the effects of JTPA training programs on the distribution of earnings. The estimation uses a new instrumental variable (IV) method that measures program impacts on quantiles. The quantile treatment effects (QTE) estimator reduces to quantile regression when selection for treatment is exogenously determined. QTE can be computed as the solution to a convex linear programming

  6. 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,

  7. Valves Module

    NSDL National Science Digital Library

    The Center for the Advancement of Process Technology presents this free sample module on valves in the process industries. The interactive resource includes 55 screens and will help learners with both the details of valve systems and the process technician's role in valve operation and maintenance.

  8. Heart valve surgery

    MedlinePLUS

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves, Prosthetic valves ... place. The main types of new valves are: Mechanical -- made of man-made materials, such as metal ( ...

  9. 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.

  10. 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),

  11. 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.

  12. 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.

  13. Earthquake relief valve

    Microsoft Academic Search

    1989-01-01

    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

  14. 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.

  15. 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.

  16. 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.

  17. Effect of endurance exercise training on heart rate variability at rest in healthy young and older men

    Microsoft Academic Search

    Wayne C. Levy; Manuel D. Cerqueira; George D. Harp; Karl-Arne Johannessen; Itamar B. Abrass; Robert S. Schwartz; John R. Stratton

    1998-01-01

    Heart rate variability (HRV) (SD of the RR interval), an index of parasympathetic tone, was measured at rest and during exercise in 13 healthy older men (age 60 to 82 years) and 11 healthy young men (age 24 to 32 years) before and after 6 months of aerobic exercise training. Before exercise training, the older subjects had a 47% lower

  18. 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.

  19. Variable structure pantograph mechanism with spring suspension system for comprehensive upper-limb haptic movement training.

    PubMed

    Perry, Joel C; Oblak, Jakob; Jung, Je H; Cikajlo, Imre; Veneman, Jan F; Goljar, Nika; Bizovi?ar, Nataša; Matja?i?, Zlatko; Keller, Thierry

    2011-01-01

    Numerous haptic devices have been developed for upper-limb neurorehabilitation, but their widespread use has been largely impeded because of complexity and cost. Here, we describe a variable structure pantograph mechanism combined with a spring suspension system that produces a versatile rehabilitation robot, called Universal Haptic Pantograph, for movement training of the shoulder, elbow, and wrist. The variable structure is a 5-degree-of-freedom (DOF) mechanism composed of 7 joints, 11 joint axes, and 3 configurable joint locks that reduce the number of system DOFs to between 0 and 3. The resulting device has eight operational modes: Arm, Wrist, ISO (isometric) 1, ISO 2, Reach, Lift 1, Lift 2, and Steer. The combination of available work spaces (reachable areas) shows a high suitability for movement training of most upper-limb activities of daily living. The mechanism, driven by series elastic actuators, performs similarly in all operational modes, with a single control scheme and set of gains. Thus, a single device with minimal setup changes can be used to treat a variety of upper-limb impairments that commonly afflict veterans with stroke, traumatic brain injury, or other direct trauma to the arm. With appropriately selected design parameters, the developed multimode haptic device significantly reduces the costs of robotic hardware for full-arm rehabilitation while performing similarly to that of single-mode haptic devices. We conducted case studies with three patients with stroke who underwent clinical training using the developed mechanism in Arm, Wrist, and/or Reach operational modes. We assessed outcomes using Fugl-Meyer Motor Assessment and Wolf Motor Function Test scores showing that upper-limb ability improved significantly following training sessions. PMID:21674386

  20. Valve assembly

    SciTech Connect

    Marshala, D.L.

    1986-12-16

    This patent describes a subsurface pump actuated by a reciprocatable sucker rod for producing well liquids from a subsurface reservoir involving a piston adapted to reciprocate within a cylinder immersed in the reservoir, the piston being provided with a traveling valve. The improvement described here comprises valve means connected to the sucker tod for lifting a body of fluid during upstrokes of the sucker rod, the valve means comprising: a barrel assembly having an internal bore and comprising: a lower barrel member; and an upper barrel assembly connected to the lower barrel and having a beveled seating surface with at least one fluid port therethrough.

  1. 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 ...

  2. 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 ...

  3. Analysis of Complex Valve and Feed Systems

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  4. 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...

  5. 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 ...

  6. Problem: Heart Valve Stenosis

    MedlinePLUS

    ... Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Stenosis Updated:May 19,2015 About Valve Stenosis ... was last reviewed on 02/18/13. Heart Valve Problems and Disease • Home • About Heart Valves • Heart ...

  7. Problem: Heart Valve Regurgitation

    MedlinePLUS

    ... Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Regurgitation Updated:Apr 24,2015 What is valve ... was last reviewed on 02/18/13. Heart Valve Problems and Disease • Home • About Heart Valves • Heart ...

  8. 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 ...

  9. Mitral Valve Prolapse

    MedlinePLUS

    Problem: Mitral Valve Prolapse Updated:Apr 24,2015 What is mitral valve prolapse (MVP)? Mitral valve prolapse is a condition in which the two valve ... mitral valve do not close smoothly or evenly. Mitral valve prolapse is also known as click-murmur syndrome, Barlow's ...

  10. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Valve locks, valves, and valve magnets. 236.383 Section 236.383 Transportation...383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off...every three months, and valves and valve magnets shall be tested at least once every...

  11. 49 CFR 236.383 - Valve locks, valves, and valve magnets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Valve locks, valves, and valve magnets. 236.383 Section 236.383 Transportation...383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off...every three months, and valves and valve magnets shall be tested at least once every...

  12. Posterior Urethral Valves

    Microsoft Academic Search

    Divyesh Y. Desai; Peter M. Cuckow

    Posterior urethral valves (PUV) remains the most common cause of bladder outflow obstruction in male infants. The condition\\u000a has an estimated incidence of 1\\/4000 to 1\\/5000 live births. It is a panurinary tract disorder with a variable spectrum of\\u000a severity that can affect both the upper and lower urinary tract.1,2

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Earthquake safety valve

    SciTech Connect

    Morris, A.W.

    1990-10-02

    This patent describes a shock sensitive self-closing safety valve for a gas pipeline. It comprises: a valve body of a non-magnetic material having inlet and outlet flow passageways with an annular, generally horizontal valve seat between them; a valve element of a magnetic material above the valve seat; a permanent magnet in the shape of a valve stem in the valve body above the valve element and movable therein toward and away from the valve element to engage and suspend same above the valve seat; spring means biasing the magnet away from the valve element; and a spacer gap of a non-magnetic material secured to the bottom of the magnet to establish the magnetic gap between the magnet and the valve element with the valve element to enable horizontal movement of the valve element while suspended by the magnet.

  18. 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.

  19. 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.

  20. Training

    Cancer.gov

    NCI offers training at laboratories and clinics in Maryland and at universities and institutions nationwide. These cancer training and career development opportunities cover a broad spectrum of disciplines for individuals at career stages ranging from high school and graduate students to scientists, clinicians, and health care professionals.

  1. 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.

  2. Heart Valve Disease

    MedlinePLUS

    ... from the NHLBI on Twitter. What Is Heart Valve Disease? Heart valve disease occurs if one or ... ability to pump blood. Overview How the Heart Valves Work At the start of each heartbeat, blood ...

  3. Mitral Valve Prolapse

    MedlinePLUS

    Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of the ... Migraine headaches Chest discomfort Most people who have mitral valve prolapse (MVP) don't need treatment because they don' ...

  4. Mitral Valve Prolapse

    MedlinePLUS

    ... page from the NHLBI on Twitter. What Is Mitral Valve Prolapse? Mitral (MI-tral) valve prolapse (MVP) is a ... blood and how your heart's electrical system works. Mitral Valve Prolapse In MVP, when the left ventricle contracts, one ...

  5. Magnetically operated check valve

    NASA Technical Reports Server (NTRS)

    Morris, Brian G. (inventor); Bozeman, Richard J., Jr. (inventor)

    1994-01-01

    A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

  6. 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 ...

  7. 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.

  8. Relief valve testing study

    Microsoft Academic Search

    2001-01-01

    Reclosing pressure-actuated valves, commonly called relief valves, are designed to relieve system pressure once it reaches the set point of the valve. They generally operate either proportional to the differential between their set pressure and the system pressure (gradual lift) or by rapidly opening fully when the set pressure is reached (pop action). A pop action valve allows the maximum

  9. 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.

  10. Remote actuated valve implant

    DOEpatents

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

    2014-02-25

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

  11. Mitral Valve Prolapse

    MedlinePLUS

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

  12. Mitral Valve Prolapse

    MedlinePLUS

    ... back into the left atrium. Continue What Is Mitral Valve Prolapse? In someone who has mitral valve prolapse (MVP), one or both of the valve's flaps ... most valuable player) even if you have MVP (mitral valve prolapse)! Reviewed by: Rupal Christine Gupta, MD Date reviewed: ...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Stentless tricuspid valve replacement.

    PubMed

    Walther, T; Falk, V; Schneider, J; Walther, C; Mohr, F W

    1999-11-01

    Stentless tricuspid valve replacement was performed in a 21-year-old patient with severe destructive tricuspid valve endocarditis resistant to medical therapy. Postoperative recovery was uneventful. Stentless atrioventricular valves are considered an additional treatment option besides stented valves or homograft implantations for severe right-sided endocarditis. Transvalvular hemodynamics are excellent, and right ventricular function can be preserved by suspending the valve at the papillary muscles. PMID:10585080

  1. Correlation of heart rate variability with cardiac functional and metabolic variables in cyclists with training induced left ventricular hypertrophy

    Microsoft Academic Search

    B M Pluim; C A Swenne; A H Zwinderman; A C Maan; A van der Laarse; J Doornbos; E E Van der Wall

    1999-01-01

    OBJECTIVETo examine the correlation between heart rate variability and left ventricular mass in cyclists with an athlete’s heart.METHODSLeft ventricular mass and diastolic function were determined at rest and myocardial high energy phosphates were quantified at rest and during atropine–dobutamine stress in 12 male cyclists and 10 control subjects, using magnetic resonance techniques. Ambulatory 24 hour ECG recordings were obtained, and

  2. [The state of central hemodynamics and variability of hearty rate in sportsmen with various direction of training process].

    PubMed

    Mal'tsev, A Iu; Mel'nikov, A A; Vikulov, A D; Gromova, K S

    2010-01-01

    The state of the central hemodynamic and variability of heart rate (VHR) in high quality sportsmen with various direction of training processes in conditions of relative tranquility was investigated. Was discovered that in sportsmen during the endurance training (group "Endurance", n = 27) and in strength training (group "Strength", n = 17) was noted the decrease in total peripheral blood resistance (TPBR: -15%, p = 0.003 and -16%, p = 0.011 for groups "Endurance" and "Strength" accordingly). However, in group "Strength" the minute blood volume (MBV) was increased (p = 0.012), and temporal and spectral data ofVHR (RMSSD, PNN50, HF)--decreased (p < 0.05) in comparison with control group (n = 56). Part of this differences had to do with increase body mass index (p = 0.005) in the group "Strength". In "Endurance" group the VHR were increased (RMSSD, pNN50, HF, VLF, TP all p < 0.02), the mean arterial pressure was decreased (p < 0.003) without considerable differences in MVB in comparison with the control group. The received data allows to conclude, that in the state of tranquility, the hemodynamic maintenance of the organism of the sportsmen of the "Strength" group takes place on a higher level of MBV and the mechanisms of heart regulation tension. On the other hand, in sportsmen training in endurance, the low level of MBV is taken care of by less tension of the regulation mechanisms of the heart action (higher tonus of vagus). PMID:20196455

  3. 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.

  4. Variable-volume turbocharger

    SciTech Connect

    Nakazawa, N.; Matsura, Y.; Takemoto, T.; Kohketsu, S.

    1988-01-19

    A variable-volume turbocharger device is described comprising a turbine housing having at least first and second exhaust gas passages divided by a partition wall provided in the housing. The first exhaust gas passage has a large flow characteristic and the second exhaust gas passage has a small flow characteristic. A first valve means operable to open and shut the first exhaust gas passage, and a second valve means operative to open and shut the second exhaust gas passage independently from the first valve means, each of the valve means having a valve member which cooperates with a valve seat to open and shut the corresponding exhaust gas passage, the valve members being arranged so as to open toward the upstream side of the flowing direction of exhaust gas with respect to the valve seats.

  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. Heart valve surgery - series (image)

    MedlinePLUS

    ... heart valves are either natural (biologic) or artificial (mechanical). Natural valves are from human donors (cadavers), modified ... artificial valves will require anticoagulation. The advantage of mechanical valves is that they last longer-thus, the ...

  7. Muscle Strength and Damage Following Two Modes of Variable Resistance Training

    PubMed Central

    Aboodarda, Saied Jalal; George, John; Mokhtar, Abdul Halim; Thompson, Martin

    2011-01-01

    Nautilus Machine (NM) and Elastic Resistance (ER) have gained considerable popularity among athletes and recreational lifters seeking to increase muscle strength. However, there is controversy concerning the use of ER for increasing muscle hypertrophy and strength among healthy-trained individuals. The aim of the study was to compare the effect of repeated near maximal contractions by ER/NM on indicators of muscle damage including: maximal strength decrement (MVIC), rate of muscle soreness (DOMS), concentration of plasma creatine kinase (CK) and increased high muscle signal on T2 weighted images using magnetic resonance imaging (MRI). Nine healthy male subjects completed two modalities of exercise (5 sets × 10RM ER/NM) in a counterbalance cross-over study design with three weeks “wash-out” period between experiments. The MVIC was measured and DOMS rated and recorded for 4 consecutive days while blood samples were collected on day 1, 3, 5 and 7. Prior to and forty eight hours after completion of each mode of exercise, subjects underwent MRI scanning. The average of applied forces demonstrated significantly higher value for NM compared with ER (362 ± 34.2 N vs 266.73 ± 44.6 N respectively) throughout the 5 sets of dynamic exercise (all p < 0.05). However, the indicators of muscle damage (T2 relaxation time, DOMS, MVIC and serum CK) exhibited a very similar response across both modes of training. Plasma CK increased significantly following both modes of training with the peak value on Day 3 (p < 0.05). The time course of muscle soreness reached a significant level after both modes of exercise and showed a peak value on the 2nd day (p < 0.05). The T2 relaxation time demonstrated a statistically significant increase following ER and NM compared with the pre-test value (p < 0.05). The similarity of these responses following both the ER and NM exercise training session suggests that both modes of training provide a similar training stress; despite a considerably lower external force generation during ER. The importance of these findings is underlined by the fact that exercise-induced muscle damage has been shown to be the underlying mechanism of further muscle hypertrophy. Key points Exercise induced muscle soreness increased levels of plasma CK, increased MRI T2 signal and prolonged strength loss indicate the moderate to intense nature of the training protocol. The similarity of these responses following both the Elastic Resistance and Nautilus Machine exercise training session suggests that both modes of training provide a similar training stress; despite a considerably lower external force generation during ER. The data in the present study suggest elastic training is a viable mode of resistance exercise that can provide a training stimulus greater than that employed in rehabilitation settings. PMID:24149552

  8. 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

  9. Effects of practice on variability in an isochronous serial interval production task: asymptotical levels of tapping variability after training are similar to those of musicians.

    PubMed

    Madison, Guy; Karampela, Olympia; Ullén, Fredrik; Holm, Linus

    2013-05-01

    Timing permeates everyday activities such as walking, dancing and music, yet the effect of short-term practice in this ubiquitous activity is largely unknown. In two training experiments involving sessions spread across several days, we examined short-term practice effects on timing variability in a sequential interval production task. In Experiment 1, we varied the mode of response (e.g., drumstick and finger tapping) and the level of sensory feedback. In Experiment 2 we varied the interval in 18 levels ranging from 500 ms to 1624 ms. Both experiments showed a substantial decrease in variability within the first hour of practice, but little thereafter. This effect was similar across mode of response, amount of feedback, and interval duration, and was manifested as a reduction in both local variability (between neighboring intervals) and drift (fluctuation across multiple intervals). The results suggest mainly effects on motor implementation rather than on cognitive timing processes, and have methodological implications for timing studies that have not controlled for practice. PMID:23558155

  10. Aortic valve surgery - open

    MedlinePLUS

    ... There are two main types of new valves: Mechanical -- made of man-made materials, such as titanium ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood ...

  11. Mitral valve surgery - open

    MedlinePLUS

    ... place. There are two types of mitral valves: Mechanical -- made of man-made (synthetic) materials, such as ... Mechanical heart valves do not fail often. They last from 12-20 years. However, blood clots develop ...

  12. 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.

  13. Mitral Valve Prolapse

    MedlinePLUS

    ... the 2 flaps of the mitral valve swing open to let blood flow from the atrium to the ventricle. The flaps normally open only one way and the blood only flows one way. What is mitral valve prolapse? If ...

  14. Increasing stair climbing in a train station: The effects of contextual variables and visibility

    Microsoft Academic Search

    Frank F. Eves; Ellinor K. Olander; Gayle Nicoll; Anna Puig-Ribera; Carl Griffin

    2009-01-01

    Accumulation of physical activity during daily living is a current public health target that is influenced by the layout of the built environment. This study reports how the layout of the environment may influence responsiveness to an intervention. Pedestrian choices between stairs and the adjacent escalators were monitored for 7 weeks in a train station (Birmingham, UK). After a 3.5

  15. 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.

  16. Rotary valve shaft

    SciTech Connect

    Lynch, R.M.

    1992-07-07

    This patent describes a rotary valve shaft for use with an internal combustion engine having a combustion chamber port, the rotary valve shaft including at least one gas passage means. It comprises groove on the periphery of the rotary valve shaft and a means for connecting the groove with the port upon rotation of the rotary valve shaft, wherein the connecting means comprising notch adjacent to and leading into the groove.

  17. 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.

  18. [Clinical improvement after physical training in patient with severe postinfarction heart failure, who underwent prosthetic heart valve implantation and numerous coronary interventional procedures].

    PubMed

    Smolis B?k, Edyta; Rymuza, Hanna; Zera, Tymoteusz; Kraska, Alicja; D?browski, Rafa?

    2012-01-01

    The case of patient with advanced congestive heart failure, NYHA III, of ischaemic and valvular aetiology and concomitant diseases is presented. Introduction of 6-month, controlled physical training resulted in improvement of health status, exercise performance, ventilation and left ventricular function. Quality of life got significantly better. This aspect of treatment should be considered in majority of patients with heart failure. PMID:22623244

  19. 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

  20. Variable Venturi type carburetor

    SciTech Connect

    Tahata, M.; Okamoto, M.; Enomoto, H.

    1986-01-14

    This patent describes a variable venturi type carburetor composed of a number of interacting components. A crucial component is a slide valve slidably supported in a carburetor body for variable positioning across the intake passage of the carburetor body to function as a variable venturi. Also described is a butterfly throttle valve pivotably supported by the carburetor body in the intake passage downstream of the slide valve. Another component is a low-speed fuel passageway and a main fuel passageway which opens into the intake passage. The final component described is an interlocking means operatively connecting the slide valve and throttle valve for interlocked operation as well as a control means to apply external force to the valves for their operation.

  1. Thermally actuated valve

    NASA Technical Reports Server (NTRS)

    Silver, R. H.

    1973-01-01

    Effective seal in one-shot valve is made by shrink-fitting ball within cylinder; thermal expansion of cylinder, caused by contiguous source of heat, will release ball and open valve. Valve can also be adapted for repeated operation and made capable of being opened without pressurized fluid.

  2. 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.

  3. 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.

  4. 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 ...

  5. Dump valve assembly

    DOEpatents

    Owen, T.J.

    1984-01-01

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

  6. 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,

  7. Mitral Valve Prolapse

    PubMed Central

    Rosser, Walter W.

    1992-01-01

    The author discusses the pathophysiology of mitral valve prolapse and provides guidelines to identify and treat low-to high-risk mitral valve prolapse. An approach to diagnosing bacterial endocarditis and its prophylaxis are also discussed. The author reviews mitral valve prolapse syndrome and the risk of sudden death.

  8. 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.

  9. Hydraulically actuated downhole valve apparatus

    SciTech Connect

    Haugen, D.M.; Edwards, A.G.; Kinney, C.W.

    1992-10-20

    This patent describes well control apparatus including a valve device with an upper and lower marginal end connected to an elongated tubing means and positioned downhole in a borehole for conducting fluid flow from a lower part of the borehole to the surface of the ground, a packer device associated with the valve device which divides the borehole into an upper and a lower annulus, means placing the upper marginal end of the valve device in communication with the upper borehole annulus and the lower marginal end of the valve device is in communication with the lower borehole annulus. It comprises: an outer annular housing, an annular mandrel slidably received within the housing; a power chamber formed between the mandrel and the housing, a power piston attached to the mandrel and slidably received with the power chamber; means for effecting annulus pressure within the upper variable chamber; latch means by which the mandrel is latched into a plurality of different vertically spaced latch positions as the mandrel is moved respective to the housing, pressure responsive means by which the latch means is released when the upper annulus pressure is increased to a first magnitude of pressure.

  10. Effects of GUASHA on Heart Rate Variability in Healthy Male Volunteers under Normal Condition and Weightlifters after Weightlifting Training Sessions

    PubMed Central

    Wang, Xingze; Chatchawan, Uraiwan; Nakmareong, Saowanee; Silsirivanit, Atit; Wang, Yingying; Xie, Dongbei; Yang, Jinsheng; Eungpinichpong, Wichai

    2015-01-01

    Objectives. This paper aims at exploring the effects of GUASHA on heart rate variability between healthy volunteers under normal condition and weightlifters after training sessions. Methods. Ten healthy male volunteers under normal condition and 15 male weightlifters after weightlifting training sessions were recruited into two groups. Electrocardiography was recorded before and immediately after 20-minute GUASHA. HRV was calculated in both the time domain and the frequency domain. Results. Stress index was reduced, while standard deviation of N-N intervals (SDNN), proportion derived by dividing the number of interval differences of successive N-N intervals greater than 50?ms, and root mean square of successive differences (RMSSD) were enhanced after GUASHA therapy in the two groups. The changes in SDNN and RMSSD were higher in the healthy men group than in the weightlifters group. In addition, low frequency was decreased whereas high frequency was significantly increased in healthy men after the GUASHA session. Conclusions. GUASHA therapy facilitates the parasympathetic nervous activity and modulates the balance between parasympathetic and sympathetic activities in both healthy men under normal condition and weightlifters after training sessions as indicated. Although the changes of the HRV parameters were similar in both groups, the responsiveness was more pronounced in healthy men than in male weightlifters. PMID:26120346

  11. Changes in lipid profile variables in response to submaximal and maximal exercise in trained cyclists

    Microsoft Academic Search

    Mahmoud S. El-Sayed; Angelheart J. M. Rattu

    1996-01-01

    This study examined the effect of prolonged submaximal exercise followed by a self-paced maximal performance test on cholesterol (T-Chol), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC). Nine trained male athletes cycled at 70% of maximal oxygen consumption for 60 min, followed by a selfpaced maximal ride for 10 min. Venous blood samples were obtained at rest, at 30 and 60

  12. Effect of a Pessoa training aid on temporal, linear and angular variables of the working trot.

    PubMed

    Walker, V A; Dyson, S J; Murray, R C

    2013-11-01

    Development of core muscle strength is important for training and during rehabilitation following injury. A Pessoa training aid (PTA) is a system of ropes and pulleys which is commonly used during equine training and rehabilitation, but there is limited information on its effectiveness. The objective of the study was to determine the effect of the PTA on the temporal, linear and angular kinematics of the working trot. Influence of testing order on effect of a PTA was assessed in four horses. Twelve riding horses were lunged at working trot on a 16 m diameter circle without (WO) and with a PTA (WP) that was set level with the shoulder. Objective measurements were carried out using high-speed motion capture (125 Hz) and inertial measurement units. Subjective video assessment was also undertaken. When a PTA was applied there was a significant reduction in speed, stride length, head angle (P<0.0001 for all) and lumbosacral angle at maximal hindlimb retraction (P=0.0028), but no effect on limb joint angles. The highest point of the horse was significantly different between conditions (WO, poll; WP, crest) (P=0.0010). Dorsoventral displacement of the middle of the back (P?0.0001) and overall impression grade (P=0.0002) were significantly greater WP compared with WO. These findings indicated that a PTA may be beneficial for general training and rehabilitation as a method of improving posture, stimulating core muscle activation and improving overall way of going, without increasing the loading of forelimb and hindlimb structures. Further work is warranted to understand the mechanism which induces these changes. PMID:23911044

  13. 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.

  14. Effects of strength and power training on neuromuscular variables in older adults.

    PubMed

    Wallerstein, Lilian França; Tricoli, Valmor; Barroso, Renato; Rodacki A, L F; Russo, Luciano; Aihara, André Yui; da Rocha Correa Fernandes, Artur; de Mello, Marco Tulio; Ugrinowitsch, Carlos

    2012-04-01

    The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n = 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n = 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n = 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p < .05), (b) increasing quadriceps muscle CSA (p < .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p < .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass. PMID:22472578

  15. Redo mitral valve replacement using the valve-on-valve method.

    PubMed

    Miyairi, Satoshi; Koide, Masaaki; Kunii, Yoshifumi; Tsuda, Kazumasa; Ohashi, Yuko; Harada, Takashi

    2015-07-01

    Despite improvements in bioprosthetic valve function, increased human life-expectancy has led to a growing number of bioprosthetic valve deterioration cases requiring reoperation. We report 2 cases of primary tissue failure of a bioprosthetic valve, which were treated by mitral valve replacement using the valve-on-valve method. The reasons for the reoperations were a severely calcified valve annulus, and severe adhesion of a previous bioprosthetic valve. We removed only the leaflets of the bioprosthetic valve and sutured a Carbomedics OptiForm valve onto the sewing cuff of the previous bioprosthesis. No complications, including major cardiac events, were noted during the follow-up. PMID:24585313

  16. 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.

  17. Training Effects on Older Adults in Information and Communication Technologies Considering Psychosocial Variables

    ERIC Educational Resources Information Center

    Ferreira, Sónia; Torres, Ana; Mealha, Óscar; Veloso, Ana

    2015-01-01

    The main aim of this study is to contribute knowledge about the impact of the use of information and communication technologies (ICT) on the self-concept, mood, and quality of life of institutionalized older adults in retirement homes and day care centers (Portuguese institutions). It also studies the influence of independent variables such as…

  18. 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; Simão, Roberto

    2015-06-01

    Figueiredo, T, Rhea, MR, Peterson, M, Miranda, H, Bentes, CM, Machado de Ribeiro dos Reis, V, and Simão, R. Influence of number of sets on blood pressure and heart rate variability after a strength training session. J Strength Cond Res 29(6): 1556-1563, 2015-The purpose of this study was to compare the acute effects of 1, 3, and 5 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 6 months previous experience in ST participated in the study. After determining the 1 repetition maximum (1RM) load 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 3 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-minute 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, 2-minute rest interval between sets and exercises, but with 3 consecutive sets of each exercise. During the third sequence, the same protocol was followed but with 5 sets of each exercise. Before and after the training sessions, blood pressure and HRV were measured. The statistical analysis demonstrated a greater duration of postexercise hypotension after the 5-set program vs. 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 8-10 repetitions at 70% 1RM load may provide the ideal stimulus for a postexercise hypotensive response. Therefore, ST composed of upper- and lower-body exercises and performed with high volumes are capable of producing significant and extended postexercise hypotensive response. In conclusion, strength and conditioning professionals can prescribe 5 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

  19. 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.

  20. Pilot study employing heart rate variability biofeedback training to decrease anxiety in patients with eating disorders

    PubMed Central

    2014-01-01

    Heart rate variability (HRV) biofeedback, a technique which encourages slow meditative breathing, was offered to 25 in-patients with various eating disorder diagnoses-anorexia nervosa, bulimia nervosa and binge eating disorder. We found that this modality had no serious side effects, and was subjectively useful to most participants. An enhanced ability to generate highly coherent HRV patterns in patients with recent onset anorexia nervosa was observed. PMID:24917934

  1. Pilot study employing heart rate variability biofeedback training to decrease anxiety in patients with eating disorders.

    PubMed

    Scolnick, Barbara; Mostofsky, David I; Keane, Robert J

    2014-01-01

    Heart rate variability (HRV) biofeedback, a technique which encourages slow meditative breathing, was offered to 25 in-patients with various eating disorder diagnoses-anorexia nervosa, bulimia nervosa and binge eating disorder. We found that this modality had no serious side effects, and was subjectively useful to most participants. An enhanced ability to generate highly coherent HRV patterns in patients with recent onset anorexia nervosa was observed. PMID:24917934

  2. Diseases of the Tricuspid Valve

    MedlinePLUS

    Diseases of the heart valves are grouped according to which valve or valves are involved and the amount of blood flow that is disrupted by the problem. Diseases of the tricuspid and pulmonary valves are fairly rare. The tricuspid valve regulates the ...

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

    E-print Network

    Boyer, Edmond

    MOTION PLANNING CONTROL OF THE AIRPATH OF AN S.I. ENGINE WITH VALVE TIMING ACTUATORS T. Leroy , J with Variable Valve Timing actuators (VVT). Compared to standard configurations, the engine does not possess any as a disturbance by impacting on the air mass flow through the inlet valves. This impact can be estimated from real

  4. MODELING AND VALIDATION OF A HIGH SPEED ROTARY PWM ON/OFF VALVE Haink C. Tu

    E-print Network

    Li, Perry Y.

    MODELING AND VALIDATION OF A HIGH SPEED ROTARY PWM ON/OFF VALVE Haink C. Tu Center for Compact-speed on/off valves are a critical technology for enabling digital control of hydraulic systems via pulse-width- modulation (PWM). High-speed valves, when used in virtually variable displacement pumps (VVDP), increase

  5. 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

  6. Mitral replacement: clinical experience with a ball-valve prosthesis. Twenty-five years later.

    PubMed Central

    Cobanoglu, A; Grunkemeier, G L; Aru, G M; McKinley, C L; Starr, A

    1985-01-01

    The purpose of this report is to review the results of mitral valve replacement since a first report in the Annals of Surgery in 1961, in order to determine the relative importance of new valve designs versus other surgical variables. The continued use of the silastic ball valve in its 1966 configuration (Model 6120), by providing a comparative data base for other new prosthetic valves, allows this analysis. For a valid comparison with the tilting disc (Bjork-Shiley) and the porcine (Hancock and Carpentier-Edwards) valves, only results with the silastic ball valves implanted during comparable time frames should be used. (Formula: see text) Thus, there are no significant differences in the results obtained with the silastic ball valve in time frames comparable to other contemporary valves introduced in the early 1970s. Improved results, therefore, must be non-prosthetic valve related. Images FIG. 1. FIG. 2. FIG. 3. PMID:4037910

  7. Effect of supervised, periodized exercise training vs. self-directed training on lean body mass and other fitness variables in health club members.

    PubMed

    Storer, Thomas W; Dolezal, Brett A; Berenc, Matthew N; Timmins, John E; Cooper, Christopher B

    2014-07-01

    Conventional wisdom suggests that exercise training with a personal trainer (PTr) is more beneficial for improving health-related fitness than training alone. However, there are no published data that confirm whether fitness club members who exercise with a PTr in the fitness club setting obtain superior results compared with self-directed training. We hypothesized that club members randomized to receive an evidence-based training program would accrue greater improvements in lean body mass (LBM) and other fitness measures than members randomized to self-training. Men, aged 30-44 years, who were members of a single Southern California fitness club were randomized to exercise with a PTr administering a nonlinear periodized training program (TRAINED, N = 17) or to self-directed training (SELF, N = 17); both groups trained 3 days per week for 12 weeks. Lean body mass was determined by dual-energy x-ray absorptiometry. Secondary outcomes included muscle strength 1 repetition maximum (1RM), leg power (vertical jump), and aerobic capacity (V[Combining Dot Above]O2max). TRAINED individuals increased LBM by 1.3 (0.4) kg, mean (SEM) vs. no change in SELF, p = 0.029. Similarly, significantly greater improvements were seen for TRAINED vs. SELF in chest press strength (42 vs. 19%; p = 0.003), peak leg power (6 vs. 0.6%; p < 0.0001), and V[Combining Dot Above]O2max (7 vs. -0.3%; p = 0.01). Leg press strength improved 38 and 25% in TRAINED and SELF, respectively (p = 0.14). We have demonstrated for the first time in a fitness club setting that members whose training is directed by well-qualified PTrs administering evidence-based training regimens achieve significantly greater improvements in LBM and other dimensions of fitness than members who direct their own training. PMID:24276303

  8. 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.

  9. JenaValve.

    PubMed

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

    2012-09-01

    The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future. PMID:22995119

  10. Automatic rotary valve actuator

    SciTech Connect

    Cook, W.E.

    1985-03-28

    This report describes the design, construction, and operation of a microcomputer-controlled valve actuator for operating test valves requiring rotary motion of the valve stem. An AIM 65 microcomputer, using a FORTH language program, controls an air motor and air clutch mounted within an oven to accomplish testing at elevated temperatures. The valve actuator closes the test valve until a preset torque is reached and then opens the valve to its initial starting point. The number of cycles and extremes of rotation are tallied and printed as the test progresses. Provisions are made to accept remote signals to stop the test and to indicate to a remote device when the test has been stopped.

  11. Pneumatic Directional Control Valves

    NSDL National Science Digital Library

    Bartelt, Terry L. M.

    This learning object examines pneumatic directional control valves in two-way, three-way, and four-way valves. The presentation is interactive, as it allows the user to focus of certain valve types and cater their learning towards those. The site employs flash based animations, and also many other diagrams to address certain points. Overall, this site has nice presentation and allows presents a great deal of information.

  12. Valve stem oil deflector

    SciTech Connect

    Stritzke, B.G.

    1988-08-16

    This patent describes an oil deflector for attachment to a valve stem of an internal combustion engine or the like comprising a molded plastic cup having a generally cylindrical wall section and an enlarged transversely extending end wall defining a neck portion, having an opening for receiving a valve stem, a radially inwardly opening annular groove on an inner face of the opening in the neck portion, an O-ring in the groove, circumferentially spaced teeth on opposite sides of the groove each of which is engageable with a valve stem extending through the neck portion of the deflector to preclude tipping of the deflector relative to the valve stem.

  13. Tubing drain valve

    SciTech Connect

    Soderberg, P.B.

    1987-02-24

    A method is described for operating a valve means. The valve means comprises a tubular piston movable within a tubular member suitable for use in a borehole pipe string to open and close a port through the wall of the tubular member. The method comprises: biassing the valve means in its closed position; pressurizing the interior of the piston to a predetermined pressure to overcome the biassing closed force and to actuate the valve means to its open position; biassing the valve means to its open position; and actuating the valve means to its closed position by engaging a first arm of a dog pivotally mounted on the piston with an engaging means insertable through the interior of the tubular piston; moving the piston relative to the tubular member; rotating the dog about its pivot to bring a second arm of the dog into contact with a detent in the tubular member; and applying sufficient force to the first arm to continue rotating the dog about the pivot, while engaging the detent with the second arm of the dog, in order to overcome the biassing open force to actuate the valve means to its closed position. A tubing drain valve suitable for use in a borehole pipe string, comprising: a sub suitable for incorporating within a borehole pipe string; and a port between the interior and the exterior of the sub; and valve means for opening and closing the port.

  14. DISCONTINUED OR LITTLE USED LARGE GATE VALVE AND VALVE ASSEMBLY ...

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

    DISCONTINUED OR LITTLE USED LARGE GATE VALVE AND VALVE ASSEMBLY PATTERNS, PATTERN STORAGE BUILDING. - Stockham Pipe & Fittings Company, Pattern Storage, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  15. Preliminary characterization of active MEMS valves.

    SciTech Connect

    Barnard, Casey Anderson

    2010-08-01

    Partial characterization of a series of electrostatically actuated active microfluidic valves is to be performed. Tests are performed on a series of 24 valves from two different MEMS sets. Focus is on the physical deformation of the structures under variable pressure loadings, as well as voltage levels. Other issues that inhibit proper performance of the valves are observed, addressed and documented as well. Many microfluidic applications have need for the distribution of gases at finely specified pressures and times. To this end a series of electrostatically actuated active valves have been fabricated. Eight separate silicon die are discussed, each with a series of four active valves present. The devices are designed such that the valve boss is held at a ground, with a voltage applied to lower contacts. Resulting electrostatic forces pull the boss down against a series of stops, intended to create a seal as well as prevent accidental shorting of the device. They have been uniquely packaged atop a stack of material layers, which have inlaid channels for application of fluid flow to the backside of the valve. Electrical contact is supplied from the underlying printed circuit board, attached to external supplies and along traces on the silicon. Pressure is supplied from a reservoir of house compressed air, up to 100 Psig. This is routed through a Norgren R07-200-RGKA pressure regulator, rated to 150 Psig. From there flow passes a manually operated ball valve, and to a flow meter. Two flow meters were utilized; initially an Omega FMA1802 rated at 10 sccm, and followed by a Flocat model for higher flow rates up to 100 sccm. An Omega DPG4000-500 pressure gauge produced pressure measurements. Optical measurements were returned via a WYKO Interferometry probe station. This would allow for determination of physical deformations of the device under a variety of voltage and pressure loads. This knowledge could lead to insight as to the failure mechanisms of the device, yielding improvements for subsequent fabrications.

  16. Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data

    NASA Technical Reports Server (NTRS)

    Yuan, Jian; Houze, Robert A.

    2010-01-01

    Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-train satellite instruments: Moderate Resolution Imaging Spectroradiometer (MODIS) for cloud-top size and coldness, Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) for rain area size and intensity, and CloudSat for horizontal and vertical dimensions of anvils. The authors distinguish three types of MCSs: small and large separated MCSs and connected MCSs. The latter are MCSs sharing a contiguous rain area. Mapping of the objectively identified MCSs shows patterns of MCSs that are consistent with previous studies of tropical convection, with separated MCSs dominant over Africa and the Amazon regions and connected MCSs favored over the warm pool of the Indian and west Pacific Oceans. By separating the anvil from the raining regions of MCSs, this study leads to quantitative global maps of anvil coverage. These maps are consistent with the MCS analysis, and they lay the foundation for estimating the global radiative effects of anvil clouds. CloudSat radar data show that the modal thickness of MCS anvils is about 4-5 km. Anvils are mostly confined to within 1.5-2 times the equivalent radii of the primary rain areas of the MCSs. Over the warm pool, they may extend out to about 5 times the rain area radii. The warm ocean MCSs tend to have thicker non-raining and lightly raining anvils near the edges

  17. Transcatheter aortic valve-in-valve implantation for patients with degenerative surgical bioprosthetic valves.

    PubMed

    Dvir, Danny; Barbanti, Marco; Tan, John; Webb, John G

    2014-01-01

    Most surgical heart valves currently implanted are bioprosthetic tissue valves. Such valves deteriorate with time, eventually presenting with either stenosis or regurgitation. Reoperation, the current standard of care for failed valves, carries significant risk in terms of both morbidity and mortality. Implantation of a transcatheter valve inside a failed surgical valve (valve-in-valve procedure) has recently emerged as an alternative, less-invasive option. Although the procedure is similar in some aspects to transcatheter aortic valve implantation in the setting of native aortic valve stenosis, there are many differences that deserve special consideration. We review the potential and challenges of valve-in-valve implantation in patients with failing surgical aortic bioprostheses. PMID:24331437

  18. 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

  19. 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.

  20. 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. PMID:25861609

  1. Congenital vein valve aplasia

    Microsoft Academic Search

    Gunnar Plate; Lars Brudin; Bo Eklöf; Ragnar Jensen; Per Ohlin

    1986-01-01

    Congenital vein valve aplasia is often misdiagnosed and its symptoms misinterpreted as being caused by previous deep venous thrombosis. The present article reviews the literature providing data on etiology, symptomatology, and phlebographic appearance in congenital vein valve aplasia. A personal experience with 10 cases focuses on the clinico-physiological results with compression therapy and surgical treatment of superficial venous insufficiency. Compressive

  2. Temperature-Operated Valve

    NASA Technical Reports Server (NTRS)

    Morrison, Andrew D.

    1994-01-01

    Bimetallic valve stem positions orifice at end of inner pipe orifice so liquid flows to outlet when temperature lies within small range of preset value. If liquid too cold or too hot, orifices misaligned and liquid returned to source. Such as in shower, valve prevents outflow of dangerously hot or uncomfortably cold water.

  3. Valve for abrasive material

    DOEpatents

    Gardner, Harold S. (Turtle Creek, PA)

    1982-01-01

    A ball valve assembly for controlling the flow of abrasive particulates including an enlarged section at the bore inlet and an enlarged section at the bore outlet. A refractory ceramic annular deflector is positioned in each of the enlarged sections, substantially extending the useful life of the valve.

  4. Artificial neural networks in computer-assisted classification of heart sounds in patients with porcine bioprosthetic valves

    Microsoft Academic Search

    Z. Guo; L.-G. Durand; H. C. Lee; L. Allard; M.-C. Grenier; P. D. Stein

    1994-01-01

    The paper describes the design, training and testing of a three-layer feedforward back-propagation neural network for the\\u000a classification of bioprosthetic valve closure sounds. Forty-seven patients with a porcine bioprosthetic valve inserted in\\u000a the aortic position were involved in the study. Twenty-four of them had a normal bioprosthetic valve, and the other 23 had\\u000a a degenerated valve. Five features extracted from

  5. 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.

  6. 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

  7. Association between congenitally quadricuspid aortic valve and mitral valve prolapse

    PubMed Central

    George, Betsy Ann; O'Hayre, Tayler Ann

    2013-01-01

    We describe transthoracic echocardiograms in three patients with combined quadricuspid aortic valve and prolapsing mitral valve. None had symptoms of cardiac dysfunction. Two patients had precordial murmurs. A third patient was referred for evaluation of infective endocarditis. The fact that a quadricuspid aortic valve is clearly a congenital anomaly supports the view that mitral valve prolapse is a congenital anomaly that may be more strongly associated with quadricuspid aortic valves than once thought. PMID:23814388

  8. Association between congenitally quadricuspid aortic valve and mitral valve prolapse.

    PubMed

    George, Betsy Ann; O'Hayre, Tayler Ann; Schussler, Jeffrey M

    2013-07-01

    We describe transthoracic echocardiograms in three patients with combined quadricuspid aortic valve and prolapsing mitral valve. None had symptoms of cardiac dysfunction. Two patients had precordial murmurs. A third patient was referred for evaluation of infective endocarditis. The fact that a quadricuspid aortic valve is clearly a congenital anomaly supports the view that mitral valve prolapse is a congenital anomaly that may be more strongly associated with quadricuspid aortic valves than once thought. PMID:23814388

  9. Engineering the Heart: Heart Valves

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    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.

  10. 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.

  11. Simple, fast, puff valve

    NASA Astrophysics Data System (ADS)

    Kriesel, J.; Prohaska, R.; Fisher, A.

    1991-10-01

    A simple, fast, reliable diamagnetically driven gas puff valve is described. It offers an extremely quick rise time (˜100 ?s) and a large pressure rise rate (˜270 Pa/?s at a distance of 13.5 cm) with an input energy of only 90 J (600 V on a 500 ?F capacitor). Because the valve can be operated with such a small input energy, solid-state switching devices are adequate and the operation of the valve will not produce the amount of electrical noise that other valves needing higher energy often do. Our valve achieves high-density puffs at relatively low plenum pressure (380 kPa, 3.8 atm), permitting it to be extremely simple in design and easy to operate. The entire package (valve plus driving circuit) is small in size; it can fit in a volume 4 in. in diameter by 8 in. long. The valve holds about 60 cm3 of gas and has an outlet opening of 1/4 in. in diameter.

  12. 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.

  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. Percutaneous Pulmonary Valve Placement

    PubMed Central

    Prieto, Lourdes R.

    2015-01-01

    Patients with congenital heart disease and pulmonary valve disease need multiple procedures over their lifetimes to replace their pulmonary valves. Chronic pulmonary stenosis, regurgitation, or both have untoward effects on ventricular function and on the clinical status of these patients. To date, all right ventricle–pulmonary artery conduits have had relatively short lifespans. Percutaneous pulmonary valve implantation, although relatively new, will probably reduce the number of operative procedures that these patients will have to undergo over a lifetime. Refinement and further development of this procedure holds promise for the extension of this technology to other patient populations. PMID:26175629

  15. EXPERIMENTAL CONTROL OF VARIABLE CAM TIMING ACTUATORS

    E-print Network

    controlled hydraulic actuators to adjust the inlet and exhaust valve timings to the crankshaft position are exposed in Section 6. 2. MODELING OF THE VCT ACTUATOR 2.1 Physical modeling qi qo pi po xv Pe Pe Ps x Piston Spool valve Figure 1. Variable Valve Timing actuator scheme.

  16. Absent pulmonary valve

    MedlinePLUS

    ... ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 424. Brown JW, Ruzmetov M, Vijay P, Rodefeld MD, Turrentine MW. Surgical treatment of absent pulmonary valve syndrome associated with bronchial obstruction. Ann Thoracic Surg , 2006; ...

  17. Valve Sizing and Selection

    NSDL National Science Digital Library

    This website, from the Chemical Engineers' Resource Page, contains an article on how to properly size and select a control valve used in the process control industry. It also includes a list of additional resources related to process control.

  18. Get valves repaired properly

    SciTech Connect

    Robert, R.W.

    1988-02-01

    Valve users are generally unanimous in their dissatisfaction with valve reconditioning programs. Their dissatisfaction is expressed in three complaints: poor service, poor quality and total costs which often approach or exceed valve replacement costs. These complaints are clearly legitimate, and the providers of valve reconditioning services must shoulder a significant part of the blame. However, scrutiny of the reasons for dissatisfaction reveals that some portion of the blame must also be borne by the users. Since many of the practices that cause the user's complaints are rooted in the early development of this market, a review of that development is helpful in understanding how these problems arose, and leads to a better understanding of the steps necessary for improvement.

  19. Electronic transmission pressure modulation valve

    SciTech Connect

    Van Elslander, E.J.

    1984-01-01

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

  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. Valve bridge construction method

    SciTech Connect

    Greene, H.F.

    1987-07-07

    This patent describes an improved method of rebuilding a used valve bridge assembly of the type that actuates the exhaust valves in a cylinder of a diesel locomotive engine, the bridge including a cross-arm with distal ends and lash adjuster sockets adjacent to each of the distal ends. Each of the lash adjuster sockets has an opening adapted to receive a lash adjuster by being press-fit in order to provide smooth, efficient operation of the exhaust valves. The bridge has at least one lash adjuster socket with an inner diameter worn oversized so that a standard size lash adjuster can no longer be properly fitted. The improved method of: maintaining a stock of oversized lash adjusters which each include an outer cylindrical wall having a radially outwardly projecting rib member adapted to be in surface-to-surface contact with the inner surface of the lash adjuster sockets. An outer diameter dimension then is larger in diameter than the outer diameter dimension of the corresponding rib on the standard size lash adjuster; disassembling the used valve bridge, including removing the used lash adjusters from each of the lash adjuster sockets; cleaning the valve bridge, including the lash adjuster sockets formed without machining the lash adjuster sockets in the valve bridge; measuring the inner diameter dimension of each of the oversized lash adjuster sockets in the valve bridge; selecting an oversized lash adjuster from the stock of oversized lash adjusters an outer diameter dimension comparable to the measured inner diameter dimension of each of the oversized lash adjuster sockets; and reassembling the valve bridge, including press-fitting the selected oversized lash adjuster into the measured lash adjuster socket so that the radially outwardly projecting rib member is in surface to surface contact with the inner surface of the measured lash adjuster socket.

  2. Valve malfunction detection apparatus

    NASA Astrophysics Data System (ADS)

    Burley, Richard K.

    1993-07-01

    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. Application of diagnostics to determine motor-operated valve operational readiness

    Microsoft Academic Search

    Eissenberg

    1986-01-01

    ORNL has been carrying out an aging assessment of motor-operated valves (MOVs) with the primary objective of recommending diagnostic methods for detecting and trending aging. As a result of experimental investigations at ORNL, it was discovered that the motor current during a valve stroke was a very useful diagnostic parameter for detecting and trending many MOV drive train load variations.

  4. Neural network classifiers applied to condition monitoring of a pneumatic process valve actuator

    Microsoft Academic Search

    M Karpenko; N Sepehri

    2002-01-01

    As modern process plants become more complex, the ability to detect and identify the faulty operation of pneumatic control valves is becoming increasingly important. In this work, a neural network pattern classifier is employed to carry out fault diagnosis and identification upon the actuator of a Fisher–Rosemount 667 industrial process valve. The network is trained with experimental data obtained directly

  5. Actuator-valve interface optimization

    SciTech Connect

    Burchett, O.L.; Jones, R.L.

    1986-01-01

    A computer code, Actuator Valve Response (AVR), has been developed to optimize the explosive actuator-valve interface parameters so that the valve plunger velocity is at a maximum when the plunger reaches the valve tubes. The code considers three forces to act on the valve plunger before the plunger reaches the valve tubes. These are the pressure force produced by the actuator, the shear force necessary to shear the seal disks on the actuator and the valve plunger, and the friction force caused by friction between the plunger and the plunger bore. The three forces are modeled by expressions that are explicitly functions of the plunger displacement. A particular actuator-valve combination was analyzed with the computer code AVR with four different combinations of valve plunger seal disk shear strength and initial friction force. (LEW)

  6. Understanding Heart Valve Problems and Causes

    MedlinePLUS

    Understanding Heart Valve Problems and Causes Updated:May 19,2015 Many heart valve problems are first identified by the ... Congenital Heart Defect See all of our brochures Heart Valve Problems and Disease • Home • About Heart Valves • ...

  7. 39. TAINTER GATE VALVES, OPERATING MACHINERY, AND VALVE ASSEMBLED AUXILIARY ...

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

    39. TAINTER GATE VALVES, OPERATING MACHINERY, AND VALVE ASSEMBLED AUXILIARY LOCK. January 1932 - Mississippi River 9-Foot Channel Project, Lock & Dam No. 15, Upper Mississipi River (Arsenal Island), Rock Island, Rock Island County, IL

  8. 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

  9. 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

  10. 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). PMID:25870807

  11. Anterior urethral valve associated with posterior urethral valves: report of 2 cases and review of the literature.

    PubMed

    Tran, Christine N; Reichard, Chad A; McMahon, Daniel; Rhee, Audrey

    2014-08-01

    Anterior urethral valve (AUV) associated with posterior urethral valves (PUVs) is an extremely rare congenital urologic anomaly resulting in lower urinary tract obstruction. We present our experience with 2 children with concomitant AUV and PUV as well as a literature review. The clinical presentation of concomitant AUV and PUV is variable. Successful endoscopic management can result in improvement in renal function, reversal of obstructive changes, and improvement or resolution of voiding dysfunction. PMID:24958476

  12. 83. Interior of 42 valve house; the motor and valve ...

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

    83. Interior of 4-2 valve house; the motor and valve mechanism is identical to that in the 4-1 valve house. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  13. 81. View of 41 valve house (right) and 42 valve ...

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

    81. View of 4-1 valve house (right) and 4-2 valve house (left); in the foreground is penstock which extends from Penstock No. 1 to the 4-1 valve house; looking south. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  14. Assessing Technical Training Needs.

    ERIC Educational Resources Information Center

    Schwaller, Anthony E.; Slipy, Dave

    1985-01-01

    Describes the results of a joint project of St. Cloud State University (Minnesota) and DeZURIK Corporation (a manufacturer and distributor of industrial valves) which developed and implemented a technical training needs questionnaire for use with the company's employees. Student involvement in the process is noted. (MBR)

  15. Options for Heart Valve Replacement

    MedlinePLUS

    ... replacement. In this condition, the mitral valve allows oxygenated blood to flow backwards into the lungs instead ... step interactive guide explaining your valve issue and treatment options with helpful videos, text summaries and links ...

  16. Improved Artificial Heart Valve Approved

    MedlinePLUS

    ... medlineplus/news/fullstory_153138.html Improved Artificial Heart Valve Approved Changes designed to minimize leaks To use ... newest version of the Sapien 3 Transcatheter Heart Valve has been approved by the U.S. Food and ...

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

    E-print Network

    Paris-Sud XI, Université de

    . These structures have been studied in order to drive the valves of a car motor. According to general specifications, a description of the design and sizing of variable reluctance or permanent magnet devices is given. The main qualities of each structure are enhanced. Keywords: Linear motion actuator, variable reluctance, permanent

  18. Smart valves open window to process

    SciTech Connect

    Grumstrup, B. [Fisher Controls International, Marshalltown, IA (United States)

    1995-01-01

    Technology is driving the development of smart valve-mounted field devices and emerging fieldbus protocols. These devices will be able to perform advanced functions, which are not possible with traditional analog products. The communicating digital valve controller (DVC) will also store in memory detailed maintenance and identification information. Today`s analog field instrumentation provides very little information to the distributed control system (DCS) or the business systems that reside above the DCS. Essentially the only information the operator receives is contained in one variable, the process variable. Traditional final control systems are unable to provide operators with direct information. Implied valve position (IVP) and feedback of the process variable from the transmitter are the only information available. All other information about the process or the process connected devices must be determined from the process transmitter, directly or inferred. In this digital age, one variable of information is unacceptable because it will not be enough for users to maintain a competitive edge. Initially, users required smart final control systems to be compatible with 4-20 mA systems. This remains extremely important not only for existing installations, but also for maintenance and replacement markets. In new projects or major plant expansions where a new DCS is being installed, this requirement is not as important as integration with the DCS. Users also required that smart final controls operate on installed wiring. This means that communications and power for smart field equipment must continue to share the same pair of wires. It is critical that these digital devices control the valve position with the same speed and improved positioning accuracy. Furthermore, users wanted them in intrinsically safe or explosion-proof installations. High reliability is another requirement that is not open to compromise. 2 figs.

  19. The natural history of aortic valve disease after mitral valve surgery

    Microsoft Academic Search

    Mordehay Vaturi; Avital Porter; Yehuda Adler; Yaron Shapira; Gideon Sahar; Bernardo Vidne; Alex Sagie

    1999-01-01

    OBJECTIVESThe present study evaluates the long-term course of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery.BACKGROUNDLittle is known about the natural history of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition there is no firm policy regarding the

  20. 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

  1. What Is Heart Valve Surgery?

    MedlinePLUS

    (continued) What do heart valves do? The four valves in your heart are made of thin (but strong) flaps of tissue that open and close ... through your heart in the right direction. Your valves work hard as they stretch back and forth ...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Aging Heart Valves

    NSDL National Science Digital Library

    VU Bioengineering RET Program,

    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

  7. Minimally Invasive Valve Operations

    Microsoft Academic Search

    Delos M Cosgrove; Joseph F Sabik; José L Navia

    1998-01-01

    Background. To reduce the morbidity from valvular heart operations, a right parasternal approach was introduced. We report our initial experience with the procedure.Methods. From January 1996 through July 1996, 115 patients underwent primary isolated valve procedures. One hundred (85%) patients underwent the operation through a right parasternal incision.Results. There was one hospital death secondary to a stroke on the fifth

  8. Vent Relief Valve Test

    NASA Technical Reports Server (NTRS)

    2008-01-01

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

  9. Stennis tests shuttle valves

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Flames burst from the E-1 Test Stand as Stennis Space Center engineers perform one of dozens of shuttle flow valve tests in early February. Stennis engineers teamed with Innovative Partnership Program partners to perform the tests after NASA officials delayed the launch of the STS-119 mission because of concerns with the shuttle part.

  10. 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.

  11. 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.

  12. Valve-in-Valve-in-Valve Transcatheter Aortic Valve Implantation to Treat a Degenerated Surgical Bioprosthesis in a Subaortic Position

    PubMed Central

    Nuis, Rutger-Jan; Benitez, Luis M.; Nader, Carlos A.; Perez, Sergio; de Marchena, Eduardo J.; Dager, Antonio E.

    2013-01-01

    Transcatheter aortic valve implantation for aortic stenosis has evolved as an alternative treatment for patients who are at high or excessive surgical risk. We report the case of an 84-year-old man with a degenerated surgically implanted valve in a subaortic position (9 mm below the native annulus) who underwent “valve-in-valve” transcatheter aortic valve implantation with use of a Medtronic CoreValve system. We planned to deploy the CoreValve at a conventional depth in the left ventricular outflow tract; we realized that this might result in paravalvular regurgitation, but it would also afford a “deep” landing site for a second valve, if necessary. Ultimately, we implanted a second CoreValve deep in the left ventricular outflow tract to seal a paravalvular leak. The frame of the first valve—positioned at the conventional depth—enabled secure anchoring of the second valve in a deeper position, which in turn effected successful treatment of the failing subaortic surgical prosthesis without paravalvular regurgitation. PMID:23914032

  13. 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.

  14. Miniature Latching Valve

    NASA Technical Reports Server (NTRS)

    Johnson, A. David; Benson, Glendon M.

    2008-01-01

    A miniature latching valve has been invented to satisfy a need for an electrically controllable on/off pneumatic valve that is lightweight and compact and remains in the most recently commanded open or closed state when power is not supplied. The valve includes a poppet that is moved into or out of contact with a seat to effect closure or opening, respectively, of the flow path. Motion of the poppet is initiated by electrical heating of one of two opposing pairs of nickel/titanium shape-memory alloy (SMA) wires above their transition temperature: heated wires contract to their remembered length, applying tension to pull the poppet toward or away from the seat. A latch consisting mainly of a bistable Belleville washer (a conical spring) made of a hardened stainless steel operates between two stable positions corresponding to the fully closed or fully open state, holding the poppet in one of these positions when power is not applied to either pair of SMA wires. To obtain maximum actuation force and displacement, the SMA wires must be kept in tension. The mounting fixtures at the ends of the wires must support large tensile stresses without creating stress concentrations that would limit the fatigue lives of the wires. An earlier design provided for each wire to be crimped in a conical opening with a conical steel ferrule that was swaged into the opening to produce a large, uniformly distributed holding force. In a subsequent design, the conical ferrule was replaced with a larger crimped cylindrical ferrule depicted in the figure. A major problem in designing the valve was to protect the SMA wires from a bake-out temperature of 300 C. The problem was solved by incorporating the SMA wires into an actuator module that is inserted into a barrel of the valve body and is held in place by miniature clip rings.

  15. Left Ventricular Dynamics after Aortic Valve Replacement

    PubMed Central

    Masotti, Claudio S.; Bonfranceschi, Paola; Rusticali, Guido; Rusticali, Franco; Pierangeli, Angelo

    1992-01-01

    Between January 1985 and July 1990, we studied 71 patients at our institution who underwent aortic valve replacement for either aortic valve regurgitation (40 patients) or stenosis (31 patients). The following prostheses were implanted: 25 St. Jude Medical valves (bileaflet), 16 Björk-Shiley (monoleaflet, tilting disc, 60° convexo-concave), 16 Medtronic-Hall (monoleaflet, tilting disc), and 14 Starr-Edwards (caged ball). The patients were evaluated pre-and postoperatively by means of gated blood-pool scintigraphy and Doppler echocardiography. Postoperatively, each patient was studied at 6 months, 1 year, and then annually. The evaluations focused upon 1) scintigraphically assessed left ventricular performance indicators (end-diastolic and end-systolic volume, as well as resting and exercise ejection fraction) and 2) Doppler-derived hemodynamic indexes (peak and mean transvalvular pressure gradient, effective orifice area, regurgitant flow, and systolic wall stress). Early after aortic valve replacement, 55 (77.5%) of the patients had substantial symptomatic relief, with normal hemodynamic values both at rest and during exercise (New York Heart Association functional class I or II); another 6 patients (8.5%) maintained their preoperative status in those classes. Within a year after surgery, a majority of patients showed a significant reduction in left ventricular dimensions. The patients with preoperative aortic valve stenosis had a significantly reduced end-diastolic and end-systolic volume (p<0.05), a moderately reduced left ventricular mass index (p<0.01), and a significantly increased exercise ejection fraction (p<0.05); moreover, in all 31 of these cases, systolic wall stress returned to normal or lower-than-control values (p<0.005). The patients with preoperative aortic valve regurgitation had a significant reduction in end-diastolic and end-systolic volume (p<0.005), diastolic wall stress (p<0.005), and a significant increase in exercise ejection fraction (p<0.01); however, their left ventricular mass index was not significantly reduced. Optimal long-term survival was afforded by the St. Jude valve in the small size (21 mm) and the Starr-Edwards valve in the large size (27 mm). This study represents the first reported use of a serial, combined radionuclide and echocardiographic procedure for the follow-up of patients undergoing aortic valve replacement. During the 5½-year follow-up period, this combined technique proved highly accurate for collecting follow-up data, often complementing or correcting simple ultrasound results. This diagnostic approach enabled us to 1) obtain information comparable to or better than that provided by cardiac catheterization, 2) identify complications early, 3) differentiate between valvular and ventricular failure, and 4) suggest the valve of choice (not always that with the best hemodynamic performance) in patients with different cardiac variables. Further research is needed to confirm this study, the results of which could change many medical and surgical strategies for clinical management of the diseased aortic valve. (Texas Heart Institute Journal 1992; 19:97-106) Images PMID:15227421

  16. Effect of Chronic Training on Heart Rate Variability, Salivary IgA and Salivary Alpha-Amylase in Elite Swimmers with a Disability

    PubMed Central

    Edmonds, Rohan

    2015-01-01

    The purpose of this study was to a) determine the heart rate variability (HRV) and saliva markers of immunity (salivary immunoglobulin A; sIgA) and stress (salivary alpha-amylase; sAA) responses to chronic training in elite swimmers with a disability; and b) identify the relationships between HRV, sIgA, sAA and training volume. Eight members of a high performance Paralympic swimming program were monitored for their weekly resting HRV, sIgA and sAA levels in the 14 weeks leading up to a major international competition. The 14 week training program included aerobic, anaerobic, power and speed, and taper training phases, while also incorporating two swimming step tests and two swimming competitions. Specific time (root mean square of the successive differences; RMSSD) and frequency (high frequency normalized units [HFnu]) domain measures, along with non-linear indices (standard deviation of instantaneous RR variability; SD1 and short term fractal scaling exponent; ?1) of HRV were used for all analyses with effects examined using magnitude-based inferences. Relationships between HRV and saliva markers were identified by Spearman rank rho (?) correlation coefficients. Compared with week 1, SD1 was very likely lower (96/4/0, ES = -2.21), while sAA was very likely elevated (100/0/0, ES = 2.32) at the beginning of week 7 for all athletes. The training program did not alter HRV or saliva whereas competition did. There were also no apparent differences observed for HRV, sIgA and sAA between each of the training phases during the 14 week swimming program. Correlations were observed between sAA and SD1 (? = -0.212, p<0.05), along with sAA and mean HR (? = 0.309, p<0.05). These results show that high level national competition influences depresses HRV (SD1) and increases saliva biomarkers of stress (sAA). It appears that a well-managed and periodised swimming program can maintain these indices within normal baseline levels. The study also highlighted the parasympathetic nervous system influence on sAA. PMID:26043224

  17. Variable force solenoid pressure control for an automatic transmission

    SciTech Connect

    Lemieux, G.E.

    1989-05-30

    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 force solenoid connected to pressure regulating portions of the torque proportional pressure; a torque signal passage connecting to the variable force solenoid valve means with the pressure regulator valve means whereby the regulated pressure level maintained by the main regulator valve means is controlled in response to changes in the torque proportional pressure; and a variable force solenoid pressure relief valve means communicating with the torque signal passage and with the variable force solenoid valve means whereby the variable force solenoid valve means is adapted to regulate and to develop a pressure of reduced value relative to the regulated pressure of the main pressure regulator valve means as it establishes the torque proportional pressure, the solenoid pressure relief valve means comprising a pressure regulating valve spool, a valve chamber receiving the spool. The spool and the valve chamber having registering valve lands, a valve spring on one side of the spool urging the spool in one direction, a first pressure area on the pool being exposed to the torque proportional pressure, a second pressure area on the valve spool exposed to the pressure of reduced value whereby the spring, the pressure of reduced value and the torque proportional pressure establish a balanced force on the spool.

  18. Is meditation always relaxing? Investigating heart rate, heart rate variability, experienced effort and likeability during training of three types of meditation.

    PubMed

    Lumma, Anna-Lena; Kok, Bethany E; Singer, Tania

    2015-07-01

    Meditation is often associated with a relaxed state of the body. However, meditation can also be regarded as a type of mental task and training, associated with mental effort and physiological arousal. The cardiovascular effects of meditation may vary depending on the type of meditation, degree of mental effort, and amount of training. In the current study we assessed heart rate (HR), high-frequency heart rate variability (HF-HRV) and subjective ratings of effort and likeability during three types of meditation varying in their cognitive and attentional requirements, namely breathing meditation, loving-kindness meditation and observing-thoughts meditation. In the context of the ReSource project, a one-year longitudinal mental training study, participants practiced each meditation exercise on a daily basis for 3months. As expected HR and effort were higher during loving-kindness meditation and observing-thoughts meditation compared to breathing meditation. With training over time HR and likeability increased, while HF-HRV and the subjective experience of effort decreased. The increase in HR and decrease in HF-HRV over training was higher for loving-kindness meditation and observing-thoughts meditation compared to breathing meditation. In contrast to implicit beliefs that meditation is always relaxing and associated with low arousal, the current results show that core meditations aiming at improving compassion and meta-cognitive skills require effort and are associated with physiological arousal compared to breathing meditation. Overall these findings can be useful in making more specific suggestions about which type of meditation is most adaptive for a given context and population. PMID:25937346

  19. SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS - EXPERIMENTAL STUDIES

    Microsoft Academic Search

    Michael B. Rannow; Haink C. Tu; Perry Y. Li; Thomas R. Chase

    2006-01-01

    The majority of hydraulic systems are controlled using a me- tering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable d isplace- ment pumps are far more efficient as the pump only produces the required flow, but comes with the

  20. The Relationship among Counselor Demographic, Training, and Employment Variables and Self-Reported Multicultural and Gerontological Counseling Competence

    ERIC Educational Resources Information Center

    McBride, Rebecca G.

    2010-01-01

    As the "Baby Boom" population ages, the geriatric population will grow to be the largest cohort in history. Elders are considered to be members of a diverse population and, therefore, topics related to older adulthood should be addressed within multicultural training. The purpose of this study was to understand the relationship among counselor…

  1. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Inhalation and exhalation valves; check valves; minimum requirements. 84.137 Section 84...Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a)...

  2. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Inhalation and exhalation valves; check valves; minimum requirements. 84.137 Section 84...Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a)...

  3. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Alternative standards for valves-allowable percentage of valves leaking. 60.483-1 Section 60.483-1...2006 § 60.483-1 Alternative standards for valves—allowable percentage of valves leaking....

  4. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Alternative standards for valves-allowable percentage of valves leaking. 60.483-1 Section 60.483-1...2006 § 60.483-1 Alternative standards for valves—allowable percentage of valves leaking....

  5. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Alternative standards for valves-allowable percentage of valves leaking. 60.483-1 Section 60.483-1...2006 § 60.483-1 Alternative standards for valves—allowable percentage of valves leaking....

  6. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Inhalation and exhalation valves; check valves; minimum requirements. 84.137 Section 84...Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a)...

  7. 40 CFR 60.483-1 - Alternative standards for valves-allowable percentage of valves leaking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Alternative standards for valves-allowable percentage of valves leaking. 60.483-1 Section 60.483-1...2006 § 60.483-1 Alternative standards for valves—allowable percentage of valves leaking....

  8. Mechanical Prosthetic Valve Thrombosis: Case Report and Review of the Literature

    Microsoft Academic Search

    Bruce D. Klugherz; Howard C. Herrmann

    1998-01-01

    Mechanical prosthetic valve thrombosis is a life-threatening complication necessitating immediate intervention. The presenting signs and symptoms of this illness are somewhat variable, but physical examination and transesophageal echocardiography enable rapid diagnosis. To avoid catastrophic complications, valve replacement or debridement, or thrombolysis in the correct setting, must be performed without delay. It is not entirely clear which therapy is superior. For

  9. Characteristics of tracheostomy phonation valves.

    PubMed

    Prigent, H; Orlikowski, D; Blumen, M B; Leroux, K; Legrand, L; Lejaille, M; Falaize, L; Ruquet, M; Raphael, J-C; Lofaso, F

    2006-05-01

    Phonation valves are commonly used devices that allow the restoration of speech in tracheostomised patients. However, their use should not compromise the physiological benefit of tracheostomy. Six commercialised phonation valves were studied in a dynamic set-up simulating a respiratory frequency of 20 breaths.min(-1), a tidal volume of 0.5 L and a peak flow rate of 0.5 L.s(-1). Resistance and additional work of breathing (WOB) were calculated. In 10 tracheostomised patients, evaluations using no phonation valve (baseline), and the most and one of the least resistive valves were carried out. Respiratory patterns and gas exchanges were recorded. Inspiratory difficulty was evaluated using the modified Borg scale. Valves displayed a wide array of resistance ranging 1.3-5.9 cmH2O.L(-1).s(-1). Additional WOB varied with a ratio of 4.4 between the best and the worst valve. While the different clinical conditions did not modify respiratory patterns and gas exchanges, a significant effect on the Borg scale rating was observed using ANOVA and post hoc analysis of baseline versus worst valve and one of the best valves versus worst valve. In conclusion, the variety of aerodynamic characteristics of phonation valves should be considered when choosing the device, according to the underlying condition of the patients benefiting from their use. PMID:16707394

  10. 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.

  11. 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.

  12. Operational experience using the novel FixCup collecting main valve

    SciTech Connect

    Giertz, J.; Huhn, F. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). Inst. for Cokemaking and Fuel Technology; Spitz, J. [Thyssen Stahl AG, Duisburg (Germany)

    1996-12-31

    On the occasion of the 1995 AIME conference the new PROven (Pressure Regulated Oven) process to control the pressure in coke ovens individually was introduced. This process was made feasible with a new collecting main valve, termed FixCup, with the aid of this valve a variable flow resistance to the raw gas discharge can be realized using a water immersion system. However, just the application of the FixCup system alone--without any pressure regulation--is very advantageous and cost saving. Thyssen has equipped 30 ovens with the new valve. The special constructive features as well as the operational experience using the FixCup valve are treated.

  13. NONLINEAR MAGNETIC LEVITATION OF AUTOMOTIVE ENGINE VALVES

    E-print Network

    Grizzle, Jessy W.

    NONLINEAR MAGNETIC LEVITATION OF AUTOMOTIVE ENGINE VALVES K. Peterson, J.W. Grizzle, and A, the controller is designed for and implemented on an electromagnetic valve actuator for use in automotive engines on an electromagnetic valve actuator for use in the actuation of automotive engine valves. 2. ELECTROMAGNETIC VALVE

  14. Valve operating system for internal combustion engine

    Microsoft Academic Search

    M. Matsuura; M. Nakamori; M. Kuroki

    1988-01-01

    This patent describes a valve operating system for an internal combustion engine, comprising an intake rotary valve and an exhaust rotary valve separately disposed in an intake passage and an exhaust passage, respectively, which independently communicate with a combustion chamber defined between a piston and a cylinder head in an internal combustion engine, the valves including spherical valve bodies adapted

  15. Heart Valve Lesson Plan Biomedical Engineering

    E-print Network

    Provancher, William

    of a leaking heart valve include fatigue, dizziness, swollen feet or ankles, and shortness of breath. Leaking leaking human heart valves. Biomedical engineers must create a heart valve that can open and close human heart valves, or some engineers have designed artificial heart valves to work like some water

  16. CONTROL VALVE TESTING PROCEDURES AND EQUATIONS

    E-print Network

    Rahmeyer, William J.

    APPENDIX A CONTROL VALVE TESTING PROCEDURES AND EQUATIONS FOR LIQUID FLOWS #12;APPENDIX A CONTROL VALVE TESTING PROCEDURES AND EQUATIONS FOR LIQUID FLOWS 2 Cv Q P Sg net gpm net = / Cv = Q P / Sg 75 is used to relate the pressure loss of a valve to the discharge of the valve at a given valve opening

  17. Percutaneous pulmonary valve replacement.

    PubMed

    Frigiola, Alessandra; Nordmeyer, Johannes; Bonhoeffer, Philipp

    2009-05-01

    Percutaneous pulmonary valve implantation helps in prolonging the lifespan of surgically placed right ventricle-to-pulmonary artery (RV-PA) conduits, and represents a less invasive alternative to repeat open-heart surgery. The clinical indications for treatment match those of surgery. As far as the suitability is concerned, the current ideal substrate is a degenerated RV-PA conduit, because of the presence of a certain degree of calcification that offers a safe anchoring point. So far, patients have been treated with low morbidity and mortality that were further improved with increasing experience. After percutaneous pulmonary valve implantation, patients experience a subjective improvement, mirrored by an objective increase of measured exercise capacity parameters and by reduced RV-PA gradient, regurgitant fraction, and RV volumes. New developments in the experimental field should result in an extension of indications in the future. PMID:19322077

  18. Rotary multiposition valve

    DOEpatents

    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.

  19. 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.

  20. Evolution of mechanical heart valves.

    PubMed

    DeWall, R A; Qasim, N; Carr, L

    2000-05-01

    The need for prosthetic heart valves was long recognized but seemed an impossible dream before 1952 when Dr Charles Hufnagel clinically introduced a ball valve that he placed into the descending thoracic aorta for treatment of aortic valvular insufficiency. Fulfillment of that dream became a reality with the advent of extracorporeal circulation in the early 1950s. Development of prosthetic heart valves involved the search for biologically compatible materials and hemologically tolerant designs. Success could not be achieved without the union of these two factors. As there was no satisfactory mechanism to scientifically achieve this goal, trial and error was the method of choice. The development of prosthetic heart valves became the purview of the cardiovascular surgeon who often collaborated with engineers. To distinguish one valve from another each prosthesis often became identified with the surgeon developer. The development of bioprostheses occurred later in the development of artificial heart valves and constitutes a separate subject not covered in this presentation. PMID:10881865

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Transportation 3 2010-10-01 2010-10-01 false Valves. 195.116 Section 195.116 Transportation...LIQUIDS BY PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with...

  7. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Transportation 3 2011-10-01 2011-10-01 false Valves. 195.116 Section 195.116 Transportation...LIQUIDS BY PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with...

  8. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Transportation 3 2014-10-01 2014-10-01 false Valves. 195.116 Section 195.116 Transportation...LIQUIDS BY PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with...

  9. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Transportation 3 2013-10-01 2013-10-01 false Valves. 195.116 Section 195.116 Transportation...LIQUIDS BY PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with...

  10. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Valve maintenance. 195.420 Section 195...Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve that is necessary for the safe...

  11. 49 CFR 195.116 - Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Transportation 3 2012-10-01 2012-10-01 false Valves. 195.116 Section 195.116 Transportation...LIQUIDS BY PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with...

  12. 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.

  13. 49 CFR 195.260 - Valves: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Valves: Location. 195.260 ...PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT...TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF HAZARDOUS...Construction § 195.260 Valves: Location. A valve...

  14. 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.

  15. Continuous-flow gas-lift installation design utilizing production-pressure-operated valve performance

    SciTech Connect

    Winkler, H.W. [Texas Tech Univ., Lubbock, TX (United States)

    1995-12-31

    The variable-gradient design-line method is a widely accepted procedure for spacing gas-lift valves (GLVs) in a continuous-flow gas-lift (GL) installation. Injection-pressure-operated (IPO) and production-pressure-operated (PPO) GLVs can be used in a variable gradient designed installation. The primary purpose of GLVs is to unload a well to the desired depth of gas injection. If the installation design is based on a constant surface injection-gas pressure (p{sub io}), the GLVs must be opened by an increase in the flowing-production pressure at valve depth (p{sub pfD}) rather than an increase in injection-gas pressure at valve depth (p{sub ioD}). PPO, also called fluid-operated, valves are opened and closed by changes in p{sub pfD}. This paper outlines in detail the calculations for a variable-gradient continuous-flow installation design procedure based on a constant p{sub io} for spacing the unloading PPO valves. The valve spacing and port size selection includes performance characteristics of PPO GLVs. A simplified method for calculating the injection daily volumetric gas rate (q{sub gsc}) throughput of an unbalanced bellows type of PPO valve on the basis of a change in p{sub pfD} and the valve bellows-assembly load rate (B{sub lr}) is given in the Appendix.

  16. 241-AN-B valve pit manifold valves and position indication acceptance test procedure

    SciTech Connect

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for gear actuated ball valves installed in 241-AN-B Valve Pit located at 200E Tank Farms. The purpose of this procedure is to demonstrate the following: Equipment is properly installed, labeled, and documented on As-Built drawings; New Manifold Valves in the 241-AN-B Valve Pit are fully operable using the handwheel of the valve operators; New valve position indicators on the valve operators will show correct valve positions; New valve position switches will function properly; and New valve locking devices function properly.

  17. 241-AN-A valve pit manifold valves and position indication acceptance test procedure

    SciTech Connect

    VANDYKE, D.W.

    1999-08-25

    This document describes the method used to test design criteria for gear actuated ball valves installed in 241-AN-A Valve Pit located at 200E Tank Farms. The purpose of this procedure is to demonstrate the following: Equipment is properly installed, labeled, and documented on As-Built drawings; New Manifold Valves in the 241-AN-A Valve Pit are fully operable using the handwheel of the valve operators; New valve position indicators on the valve operators will show correct valve positions; New valve position switches will function properly; and New valve locking devices function properly.

  18. Stentless mitral valve replacement using the quattro valve.

    PubMed

    Walther, T; Walther, C; Falk, V; Krüger, M; Dagge, A; Diegeler, A; Autschbach, R; Mohr, F W

    1999-10-01

    This study analyzed early clinical results after stentless mitral valve (Quadrileaflet Mitral Valve (QMV)/Quattro) implantation. A total of 28 patients have received a Quattro valve since August 1997. Patient age was 69+/-8 years; the underlying disease was mitral incompetence (14) and stenosis (13). Preoperative New York Heart Association functional class was 3.2+/-0.4 and cardiac index was 1.8+/-0.6. Mean cross-clamp duration was 58+/-19 minutes. Twenty patients received a 28-mm prosthesis, and eight patients received a 30-mm prosthesis. Four patients had myocardial revascularization, two had tricuspid valve repair, and six had radiofrequency ablation therapy to restore sinus rhythm. Mortality (1) was nonvalve related. Reoperation was necessary in two patients for posterior paravalvular leakage (1) and for functional stenosis (1). Echocardiography showed satisfactory hemodynamic function. By stentless mitral valve implantation the annuloventricular continuity is preserved to stabilize left ventricular function. The Quattro valve resembles native mitral valve function and is well suited for mitral valve replacement. PMID:10660190

  19. 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.

  20. 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.

  1. Reed valve mechanism for engines

    Microsoft Academic Search

    Boyesen

    1989-01-01

    This patent describes a reed valve mechanism for use in a fuel\\/air supply passage of an internal combustion engine. It comprises: a V-shaped reed cage with its apex presented downstream of the direction of the flow through the supply passage, the reed cage having converging side walls with valve ports therein communicating with the supply passage, the side walls having

  2. Air flow through poppet valves

    NASA Technical Reports Server (NTRS)

    Lewis, G W; Nutting, E M

    1920-01-01

    Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.

  3. 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.

  4. 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.

  5. Standards for heart valve surgery in a ‘Heart Valve Centre of Excellence’

    PubMed Central

    Chambers, John; Ray, Simon; Prendergast, Bernard; Graham, Tim; Campbell, Brian; Greenhalgh, Donna; Petrou, Mario; Tinkler, Jeremy; Gohlke-Bärwolf, Christa; Mestres, Carlos A; Rosenhek, Raphael; Pibarot, Philippe; Otto, Catherine; Sundt, Thoralf

    2015-01-01

    Surgical centres of excellence should include multidisciplinary teams with specialist expertise in imaging, clinical assessment and surgery for patients with heart valve disease. There should be structured training programmes for the staff involved in the periprocedural care of the patient and these should be overseen by national or international professional societies. Good results are usually associated with high individual and centre volumes, but this relationship is complex. Results of surgery should be published by centre and should include rates of residual regurgitation for mitral repairs and reoperation rates matched to the preoperative pathology and risk. PMID:26180639

  6. Fuel injection valve

    SciTech Connect

    Ishibashi, T.; Taira, S.

    1986-09-23

    A fuel injection valve is described for an internal combustion engine, including a main body having injection holes formed in a tip thereof and a fuel intake passageway formed therein and communicating with the injection holes, a nozzle needle slidably fitted within the main body for alternately closing and opening the injection holes, a plunger chamber defined within the main body, a lift-limiting plunger slidably fitted in the plunger chamber and having an end face remote from the nozzle needle disposed as a pressure-receiving surface to receive fuel pressure for limiting the lifting amount of the nozzle needle and a back pressure chamber. The improvement described here consists of a pressure inlet chamber permanently communicating with the back pressure chamber and disposed to be selectively communicated with the fuel intake passageway and disconnected therefrom by the selector valve, in synchronism with the selective establishment and interruption of communication between the back pressure chamber and the fuel intake passageway; an accumulator chamber communicating with the pressure inlet chamber; an accumulator slidably fitted within the accumulator chamber and liftable in a direction away from the pressure inlet chamber with an increase in the pressure within the pressure inet chamber; and urging means urging the accumulator in a direction toward the pressure inlet chamber against lifting of the accumulator.

  7. Protocol for relative hydrodynamic assessment of tri-leaflet polymer valves.

    PubMed

    Ramaswamy, Sharan; Salinas, Manuel; Carrol, Rob; Landaburo, Karla; Ryans, Xavier; Crespo, Cynthia; Rivero, Ailyn; Al-Mousily, Faris; DeGroff, Curt; Bleiweis, Mark; Yamaguchi, Hitomi

    2013-01-01

    Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide insights on functional aspects of polymer valve design. PMID:24193435

  8. 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.

  9. Enhancement of nonlocal spin-valve signal using spin accumulation in local spin-valve configuration

    E-print Network

    Otani, Yoshichika

    Enhancement of nonlocal spin-valve signal using spin accumulation in local spin-valve configuration) We propose a nonlocal spin-valve measurement combined with a local spin-valve structure to enlarge spin signal. The probe configuration consists of a lateral spin valve with three Ni­Fe wires bridged

  10. Outcomes of primary valve ablation versus urinary tract diversion in patients with posterior urethral valves

    Microsoft Academic Search

    Walid Farhat; Gordon McLorie; Gianpaolo Capolicchio; Antoine Khoury; Darius Bägli; Paul A Merguerian

    2000-01-01

    Objectives. Although valve ablation is the treatment of choice for patients with posterior urethral valves, debate continues as to the role of urinary diversion. We sought to retrospectively compare the clinical and radiologic outcomes between valve ablation and urinary diversion for patients with posterior urethral valves.Methods. We retrospectively reviewed the records of 50 consecutive patients with posterior urethral valves since

  11. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Valves. 192.145 Section 192.145 Transportation...Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...

  12. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Valves. 192.145 Section 192.145 Transportation...Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...

  13. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 2010-10-01 false Valves. 192.145 Section 192.145 Transportation...Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...

  14. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 2012-10-01 false Valves. 192.145 Section 192.145 Transportation...Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...

  15. Heart valve tissue engineering Frank Baaijens

    E-print Network

    Stavroulakis, Georgios E.

    Heart valve tissue engineering Frank Baaijens Department of Biomedical Engineering Eindhoven University of Technology Netherlands Tissue engineered heart valves appear promising as autologous valvular functionality and durability of the heart valve relies on the strength and anisotropic properties of the valve

  16. 49 CFR 192.145 - Valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Valves. 192.145 Section 192.145 Transportation...Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum...

  17. Aortic valve rupture during isometric muscle contraction.

    PubMed

    Payne, Darrin M; Richards, Tammy; Hamilton, Andrew

    2015-05-01

    Aortic valve rupture has been previously reported in association with blunt chest trauma as well as spontaneously in the setting of abnormal valves. We present a case of a patient who required emergent aortic valve replacement following rupture of his aortic valve during an isometric muscle contraction. PMID:25728450

  18. Fast acting switching valves for servopneumatics

    Microsoft Academic Search

    Veit Zoppig; Karsten Feindt; Tom Strohla; E. Kallenbach

    2003-01-01

    The paper discusses the application of switching valves with electromagnetic actuators for servopneumatic drives. Fast acting (switching times of 1 ms or less) valves with nominal bores of 1 mm or more (at the industrial pressure of 6 bar) are needed in order to replace expensive 5\\/3-way proportional valves. Due to these requirements the electromagnetic valve has to be designed

  19. Oil well testing string bypass valve

    Microsoft Academic Search

    T. E. Mcgraw; J. C. Zimmerman

    1981-01-01

    An improved bypass valve for use with an oil well testing string is disclosed which includes a check valve means for allowing fluid flow from the interior of the test string to the well annulus when the interior pressure exceeds the well annulus pressure. The bypass valve further includes a blocking means which blocks interior communication with the check valve

  20. Outcome following isolated tricuspid valve replacement

    Microsoft Academic Search

    Arduino A Mangoni; Thomas G DiSalvo; Gus J Vlahakes; Carisi A Polanczyk; Michael A Fifer

    2001-01-01

    Objectives: The clinical outcome of isolated tricuspid valve replacement is not well defined because this procedure is usually performed concomitantly with other valve surgery. Methods: We retrospectively studied the short and long-term outcome of 15 consecutive patients (six men and nine women, aged 61±3 years) undergoing isolated tricuspid valve replacement from 1984 to 1996. The cause of valve dysfunction was

  1. 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.

  2. Effects of variable training, signaled and unsignaled delays, and d-amphetamine on delay-discounting functions.

    PubMed

    Slezak, Jonathan M; Anderson, Karen G

    2009-09-01

    One common procedure for obtaining delay-discounting functions consists of a choice between a larger reinforcer that is presented after an increasing delay and a smaller reinforcer that is always presented immediately within session. Repeating the same context of delay presentation (e.g. ascending delay order) in a discrete-choice paradigm, however, may lead to a perseverative response pattern when rats are used as subjects. The purpose of this study was to increase the variability in delay presentation (i.e. ascending and descending delays) in an attempt to reduce a perseverative response pattern and gain tighter control over choice by reinforcer amount and delay. For one group of rats (n = 8), delays to reinforcer presentation were differentially signaled by a flashing houselight and for one group of rats (n = 8) the delays were unsignaled. Effects of delay signal and d-amphetamine on choice were evaluated in both groups. Similar rates of delay discounting and area under the curve (AUC) were observed with both ascending and descending delay presentations and with signaled and unsignaled delays to reinforcement. Increasing the variability in delay order resulted in differences in the choice pattern during 0-s probe sessions. d-Amphetamine had little or no effect on AUC at low doses, but decreased AUC at the highest doses tested, that is, 1.0 and 1.7 mg/kg. Some of the changes in AUC after d-amphetamine administration may have been because of disruption in discrimination of the different food amounts. PMID:19730365

  3. 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

  4. 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.

  5. 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.

  6. A reversible molecular valve

    PubMed Central

    Nguyen, Thoi D.; Tseng, Hsian-Rong; Celestre, Paul C.; Flood, Amar H.; Liu, Yi; Stoddart, J. Fraser; Zink, Jeffrey I.

    2005-01-01

    In everyday life, a macroscopic valve is a device with a movable control element that regulates the flow of gases or liquids by blocking and opening passageways. Construction of such a device on the nanoscale level requires (i) suitably proportioned movable control elements, (ii) a method for operating them on demand, and (iii) appropriately sized passageways. These three conditions can be fulfilled by attaching organic, mechanically interlocked, linear motor molecules that can be operated under chemical, electrical, or optical stimuli to stable inorganic porous frameworks (i.e., by self-assembling organic machinery on top of an inorganic chassis). In this article, we demonstrate a reversibly operating nanovalve that can be turned on and off by redox chemistry. It traps and releases molecules from a maze of nanoscopic passageways in silica by controlling the operation of redox-activated bistable [2]rotaxane molecules tethered to the openings of nanopores leading out of a nanoscale reservoir. PMID:16006520

  7. 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.

  8. Saving a Life: Heart Valve Replacement

    NSDL National Science Digital Library

    2014-09-18

    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.

  9. Ischemic mitral valve prolapse: mechanisms and implications for valve repair

    Microsoft Academic Search

    Jérome Jouan; Michel Tapia; Richard C. Cook; Emmanuel Lansac; Christophe Acar

    2004-01-01

    Objective: The aim of this study was to assess the mechanisms of prolapse in ischemic mitral valve regurgitation (MR) and the techniques of valve repair. Methods: Out of 121 patients operated upon for ischemic MR, a prolapse was present in 44 patients (36.4%). The operation was performed emergently in four cases (9.1%) and electively in 40 patients (90.9%). Fifteen patients

  10. Variable Delay Multi-Pulse Train for Fast Chemical Exchange Saturation Transfer and Relayed-Nuclear Overhauser Enhancement MRI

    PubMed Central

    Xu, Jiadi; Yadav, Nirbhay N.; Bar-Shir, Amnon; Jones, Craig K.; Chan, Kannie W. Y.; Zhang, Jiangyang; Walczak, P.; McMahon, Michael T.; van Zijl, Peter C. M.

    2013-01-01

    Purpose Chemical exchange saturation transfer (CEST) imaging is a new MRI technology allowing the detection of low concentration endogenous cellular proteins and metabolites indirectly through their exchangeable protons. A new technique, variable delay multi-pulse CEST (VDMP-CEST), is proposed to eliminate the need for recording full Z-spectra and performing asymmetry analysis to obtain CEST contrast. Methods The VDMP-CEST scheme involves acquiring images with two (or more) delays between radiofrequency saturation pulses in pulsed CEST, producing a series of CEST images sensitive to the speed of saturation transfer. Subtracting two images or fitting a time series produces CEST and relayed-nuclear Overhauser enhancement CEST maps without effects of direct water saturation and, when using low radiofrequency power, minimal magnetization transfer contrast interference. Results When applied to several model systems (bovine serum albumin, crosslinked bovine serum albumin, l-glutamic acid) and in vivo on healthy rat brain, VDMP-CEST showed sensitivity to slow to intermediate range magnetization transfer processes (rate < 100–150 Hz), such as amide proton transfer and relayed nuclear Overhauser enhancement-CEST. Images for these contrasts could be acquired in short scan times by using a single radiofrequency frequency. Conclusions VDMP-CEST provides an approach to detect CEST effect by sensitizing saturation experiments to slower exchange processes without interference of direct water saturation and without need to acquire Z-spectra and perform asymmetry analysis. PMID:23813483

  11. Mitral valve surgery - minimally invasive

    MedlinePLUS

    ... rate will be slowed by medicine or a mechanical device. If your surgeon can repair your mitral ... There are two main types of new valves: Mechanical -- made of man-made materials, such as titanium ...

  12. Risks for Heart Valve Problems

    MedlinePLUS

    ... had rheumatic fever or a case of infective endocarditis are at greater risk for heart valve problems. ... needed before dental procedures to help protect against endocarditis . You should discuss your individual risk and the ...

  13. Annulus pressure controlled reversing valve

    SciTech Connect

    Upchurch, J. M.

    1984-10-02

    In accordance with an illustrative embodiment of the present invention, a pressure controlled reversing valve includes a housing defining a reversing port, a springloaded sleeve valve normally closing the reversing port, means for locking the sleeve valve in the closed position, an operator mandrel mounted for reciprocating movement within the housing, clutch means for shifting the locking means with the operator mandrel as it moves in one axial direction, means for urging the operator mandrel in the opposite axial direction, and means responsive to a series of excess annulus pressure changes for reciprocating the operator mandrel to causing shifting of the locking means by an amount sufficient to disable the same and permit the valve sleeve to open.

  14. Mitral Valve Prolapse (For Parents)

    MedlinePLUS

    ... Atrial Septal Defect Congenital Heart Defects Heart and Circulatory System Arrhythmias Getting an EKG (Video) Heart Murmurs Marfan Syndrome Mitral Valve Prolapse Your Heart & Circulatory System EKG (Video) Ventricular Septal Defect Marfan Syndrome Arrhythmias ...

  15. Living with Heart Valve Disease

    MedlinePLUS

    ... Endocarditis Heart Murmur How the Heart Works Mitral Valve Prolapse Send a link to NHLBI to someone by E-MAIL | PRINT | SHARE this page from the NHLBI BOOKMARK & SHARE X Share this page from the NHLBI on Blogger. ...

  16. Minimally Invasive Aortic Valve Replacement

    MedlinePLUS Videos and Cool Tools

    ... lot of turbulent flow, as represented by the red and the blue color. Typically, blood flowing through ... t supposed to happen, is bright blue and red. And so this valve has two problems. It's ...

  17. Aspects concerning posterior urethral valves

    Microsoft Academic Search

    M. D. Melekos; H. W. Asbach; S. Giannoulis; P. Perimenis; G. Barbalias

    1989-01-01

    Twenty-six boys were evaluated and treated for posterior urethral valves. At the time the valves were diagnosed unilateral\\u000a or bilateral vesicoureteral reflux was present in 58% of the ureters and 69% of the children, while dilatation of the upper\\u000a urinary tract was present in 88% and 92%, respectively. There was a variety of symptoms and signs, but the most prominent

  18. PERIOSTIN REGULATES ATRIOVENTRICULAR VALVE MATURATION

    PubMed Central

    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.

    2008-01-01

    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 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

  19. Elective valve-in-valve implantation for migration of a corevalve in a patient with bicuspid aortic valve stenosis.

    PubMed

    Tanaka, Yutaka; Tanaka, Masashi; Saito, Shigeru

    2015-08-01

    Transcatheter aortic valve implantation for bicuspid aortic valve stenosis (BAVS) is controversial, as its unfavorable anatomy may lead to device dislocation or malfunctioning. If device failure occurs, the bailout intervention can be more complex and technically challenging. We here report a unique case of late migration of a CoreValve (Medtronic, MN) implanted in a patient with BAVS, who was successfully treated with elective valve-in-valve implantation using the first valve as a firm scaffold after waiting for it to adhere at the migrated position. This new strategy may represent a useful salvage option for some patients with prosthesis migration. © 2015 Wiley Periodicals, Inc. PMID:25545068

  20. Acoustic monitoring of power-plant valves

    NASA Astrophysics Data System (ADS)

    Allen, J. W.; Hartman, W. F.; Robinson, J. C.

    1982-06-01

    Advanced surveillance diagnostics were applied to key nuclear power plant valves to improve the availability of the power plant. Two types of valves were monitored: BWR three-stage, pilot-operated safety/relief valves and PWR feedwater control valves. Excessive leakage across the pilot-disc seat in BWR safety/relief valves can cause the second-stage pressure to reach the critical value that activates the valve, even though the set pressure was not exceeded. Acoustic emissions created by the leak noise were monitored and calibrated to indicate incipient activation of the safety/relief valve. Hydrodynamic, vibration, control and process signals from PWR feedwater control valves were monitored by a mini-computer based surveillance system. On-line analysis of these signals coupled with earlier analytic modelling identified: (1) cavitation, (2) changes in steam packaging tightness, (3) valve stem torquing, (4) transducer oscillations, and (5) peak vibration levels during power transients.

  1. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, David M. (Oak Ridge, TN); Haynes, Howard D. (Knoxville, TN); Casada, Donald A. (Knoxville, TN)

    1993-01-01

    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.

  2. 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.

  3. Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses

    Microsoft Academic Search

    Alice Schmidt; Jörg Aurich; Erich Möstl; Jürgen Müller; Christine Aurich

    2010-01-01

    Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n=9) and mares (n=7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations,

  4. 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.

  5. 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.

  6. 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 ...

  7. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Loading and unloading valves. 179.500-11 Section 179.500-11... § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or...

  8. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Loading and unloading valves. 179.500-11 Section 179.500-11... § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or...

  9. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Loading and unloading valves. 179.500-11 Section 179.500-11... § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or...

  10. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Loading and unloading valves. 179.500-11 Section 179.500-11... § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or...

  11. 49 CFR 179.500-11 - Loading and unloading valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Loading and unloading valves. 179.500-11 Section 179.500-11... § 179.500-11 Loading and unloading valves. (a) Loading and unloading valve or valves shall be mounted on the cover or...

  12. BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE ...

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

    BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE VALVE PAINT BOOTH OF THE VALVE ASSEMBLY BUILDING. - Stockham Pipe & Fittings Company, Valve Assembly Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  13. Entake or exhaust valve actuator

    SciTech Connect

    Smietana, J.M.

    1993-08-03

    Intake or exhaust valve actuator assembly is described for an internal combustion engine for hydraulically opening and closing an intake or exhaust valve for admitting intake gases from an intake conduit into a combustion chamber or permitting exhaust gases to escape from the combustion chamber into an exhaust conduit, the engine including a piston which oscillates in the combustion chamber, a cylinder head which encloses the combustion chamber and contains the intake or exhaust valve and the intake or exhaust conduit, and timing means to detect phase of the piston as it oscillates in the combustion chamber; the intake or exhaust valve actuator assembly comprising a sleeve mounted in the cylinder head, a piston member slidably disposed in the sleeve cylindrical cavity, the piston member being affixed onto the stem of the associated intake or exhaust valve, and a rod bearing member mounted in the distal end of the sleeve for guiding the rod portion and forming a sliding seal therewith, and the sleeve having a distal port and a proximal port formed therein for communicating fluid pressure to the cylindrical cavity respectively distally and proximally of the piston member head portion; and hydraulic valve means actuated by the timing means and coupled to the distal and proximal ports to apply fluid pressure to at least one of the ports to move the piston member and open and close the associated intake or exhaust valve in accordance with the detected phase of the piston of the engine; and wherein the actuator assembly piston member is provided with a coating of titanium nitride on the cylindrical face of the head portion and on the rod portion, and wherein the mating surfaces of the sleeve cylindrical cavity and the rod bearing member are provided with a coating of a hard material of a lower hardness than the titanium nitride.

  14. Classification of heart valve single leg separations from acoustic clinical measurements

    SciTech Connect

    Clark, G.A.; Bowman, B.C.; Boruta, N.; Thomas, G.H.; Jones, H.E.; Buhl, M.R.

    1994-05-01

    Our system classifies the condition (intact or single leg separated) of in vivo Bjork-Shiley Convexo-Concave (BSCC) heart valves by processing acoustic measurements of clinical heart valve opening sounds. We use spectral features as inputs to a two-stage classifier, which first classifies individual heart beats, then classifies valves. Performance is measured by probability of detection and probability of false alarm, and by confidence intervals on the probability of correct classification. The novelty of the work lies in the application of advanced techniques to real heart valve data, and extensions of published algorithms that enhance their applicability. We show that even when given a very small number of training samples, the classifier can achieve a probability of correct classification of 100%.

  15. [Right heart failure resulting from pacemaker lead-induced tricuspid valve regurgitation].

    PubMed

    Schroeter, T; Strotdrees, E; Doll, N; Mohr, F W

    2011-06-01

    Pacemaker lead-induced tricuspid valve regurgitation is a severe and often underdiagnosed complication due to the widely variable time interval between implantation and the development of severe tricuspid valve insufficiency with ensuing right heart failure. Complete explantation of inactive pacemaker leads is necessary to avoid permanent damage to right heart structures. If performed in a timely fashion, regression of tricuspid insufficiency can be achieved without additional cardiac procedures. PMID:21547560

  16. Failure and Life Cycle Evaluation of Watering Valves

    PubMed Central

    Gonzalez, David M; Graciano, Sandy J; Karlstad, John; Leblanc, Mathias; Clark, Tom; Holmes, Scott; Reuter, Jon D

    2011-01-01

    Automated watering systems provide a reliable source of ad libitum water to animal cages. Our facility uses an automated water delivery system to support approximately 95% of the housed population (approximately 14,000 mouse cages). Drinking valve failure rates from 2002 through 2006 never exceeded the manufacturer standard of 0.1% total failure, based on monthly cage census and the number of floods. In 2007, we noted an increase in both flooding and cases of clinical dehydration in our mouse population. Using manufacturer's specifications for a water flow rate of 25 to 50 mL/min, we initiated a wide-scale screening of all valves used. During a 4-mo period, approximately 17,000 valves were assessed, of which 2200 failed according to scoring criteria (12.9% overall; 7.2% low flow; 1.6% no flow; 4.1% leaky). Factors leading to valve failures included residual metal shavings, silicone flash, introduced debris or bedding, and (most common) distortion of the autoclave-rated internal diaphragm and O-ring. Further evaluation revealed that despite normal autoclave conditions of heat, pressure, and steam, an extreme negative vacuum pull caused the valves’ internal silicone components (diaphragm and O-ring) to become distorted and water-permeable. Normal flow rate often returned after a ‘drying out’ period, but components then reabsorbed water while on the animal rack or during subsequent autoclave cycles to revert to a variable flow condition. On the basis of our findings, we recalibrated autoclaves and initiated a preventative maintenance program to mitigate the risk of future valve failure. PMID:22330720

  17. caret: Classification and Regression Training

    NASA Astrophysics Data System (ADS)

    Kuhn, Max

    2015-05-01

    caret (Classification And REgression Training) provides functions for training and plotting classification and regression models. It contains tools for data splitting, pre-processing, feature selection, model tuning using resampling, and variable importance estimation, as well as other functionality.

  18. A custom-designed limited-angle actuator for an electromechanical engine valve drive Part I: Conceptual design

    E-print Network

    Qiu, Yihui

    Research has shown that variable valve timing (VVT) can improve significantly the performance of internal combustion (IC) engines, including higher fuel efficiencies, lower emissions, and larger torque outputs at each point ...

  19. A custom-designed limited-angle actuator for an electromechanical engine valve drive Part II: Fabrication and evaluation

    E-print Network

    Kassakian, John G.

    Research has shown that variable valve timing (VVT) can improve significantly the performance of internal combustion (IC) engines, including higher fuel efficiencies, lower emissions, and larger torque outputs at each point ...

  20. Rotary valve internal combustion engine

    SciTech Connect

    Bunk, P.H.

    1989-03-28

    A rotary valve internal combustion engine is described, comprising: an engine block; at least one cylinder in the engine block; at least one cylinder having a top end; cylinder head means located adjacent the top end of at least one cylinder, the cylinder head means having a cylindrically shaped cavity therein, the cylindrically shaped cavity being oriented in perpendicular relation to at least one cylinder; a piston sealingly mounted in at least one cylinder for reciprocable movement therein, the reciprocable movement including an intake stroke and an exhaust stroke; engine shaft means rotatably mounted to the engine block; means within the engine block for converting the reciprocable movement of the piston into rotary motion of the engine shaft means; a cylinder port located at the top end of at least one cylinder; a rotary valve rotatably mounted in the cylindrically shaped cavity; means connected with the engine shaft means for rotating the rotary valve in a predetermined synchronization with the reciprocable movement of the piston; aspiration means in the rotary valve for selectively aspirating at least one cylinder during the intake an exhaust strokes; and a spark plug removably mounted within the rotary valve and rotatable therewith.

  1. 5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION ...

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

    5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION 1044. VALVE IN FOREGROUND IS A BUTTERFLY VALVE SIX FEET IN DIAMETER; VALVE TO THE REAR IS A JOHNSON-TYPE NEEDLE VALVE BOTH VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  2. Kamyr PD Series Full-Borne Ball Valve METC SOA Test Valve No. A-17 state-of-the-art lockhopper valve-testing and development project

    Microsoft Academic Search

    J. F. Gardner; R. C. Hall; R. G. Hornbeck; R. A. Griffith; T. M. Nutter; T. M. Yost; T. Vandergrift; T. R. Gayheart; D. L. Armstrong

    1981-01-01

    The Kamyr Ball Valve, METC SOA Test Valve No. A-17, accumulated 640 valve cycles in the Valve Static Test Unit and over 16,900 valve cycles in the Valve Dynamic Test Unit. During dynamic testing (with minus 8 mesh and 5\\/16'' x 1\\/8'' limestone), the stem packing was replaced twice and the valve was disassembled once to remove compacted fines from

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

    Microsoft Academic Search

    K. L McElhaney

    2000-01-01

    Although it had been theorized by nuclear industry valve experts that the two most significant factors in assessing check valve performance were valve type (or design) and operating conditions, until recently, no data was available to support their assumptions. In co-operation with the Nuclear Industry Check Valve Group (NIC), Oak Ridge National Laboratory (ORNL) undertook a review and analysis of

  4. Recurrent Ischemic Strokes in a Patient with Medtronic-Hall Prosthetic Aortic Valve and Valve Strands

    Microsoft Academic Search

    Kendra Hutchinson; Faizain Hafeez; Timothy D Woods; Paramjeet S Chopra; Thomas F Warner; Ross L Levine; Timothy J Kamp

    1998-01-01

    Fine strands associated with prosthetic heart valves have been demonstrated with transesophageal echocardiography, but the pathologic identity of these strands is unclear. A case of a man with a prosthetic aortic Medtronic-Hall valve with prominent valve strands and recurrent strokes is discussed. The patient underwent valve replacement surgery, and histopathologic examination of the strands identified them as Lambl's excrescences. (J

  5. Check valve installation in pilot operated relief valve prevents reverse pressurization

    NASA Technical Reports Server (NTRS)

    Oswalt, L.

    1966-01-01

    Two check valves prevent reverse flow through pilot-operated relief valves of differential area piston design. Title valves control pressure flow to ensure that the piston dome pressure is always at least as great as the main relief valve discharge pressure.

  6. Intro to Valve Guide Reconditioning. Automotive Mechanics. Valves. Instructor's Guide [and] Student Guide.

    ERIC Educational Resources Information Center

    Horner, W.

    This instructional package, one in a series of individualized instructional units on tools and techniques for repairing worn valve guides in motor vehicles, provides practical experience for students in working on cylinder heads. Covered in the module are reaming valve guides that are oversized to match a new oversized valve, reaming valve guides…

  7. SLM Produced Hermetically Sealed Isolation Valve

    NASA Technical Reports Server (NTRS)

    Richard, James A.

    2014-01-01

    Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic based valve.

  8. SLM Produced Hermetically Sealed Isolation Valve

    NASA Technical Reports Server (NTRS)

    Richard, James

    2014-01-01

    Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic-driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic-based valve.

  9. Percutaneous heart valves; past, present and future.

    PubMed

    Rozeik, M M; Wheatley, D J; Gourlay, T

    2014-09-01

    Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients. PMID:24637621

  10. Stem clutch for motor driven valve

    NASA Technical Reports Server (NTRS)

    Blum, D. E.; Wiltens, J. F.

    1972-01-01

    Development of mechanical device to reduce possibility of damage to motor driven needle valve is discussed. Mechanical clutch is employed to allow slippage when needle valve reaches limit of travel. Operation of system for various conditions is described.

  11. Aortic Valve Injury Following Blunt Chest Trauma

    PubMed Central

    Esmaeilzadeh, Maryam; Alimi, Hedieh; Maleki, Majid; Hosseini, Saeid

    2014-01-01

    Introduction: Heart valve injury following blunt chest trauma of car accidents is increasing. Although aortic valve involvement is rare, however, in survivors of blunt cardiac trauma it is the most commonly involved valve and the most frequent valve lesion is isolated injury of the noncoronary cusp of aortic valve. Case Presentation: A 31-year-old man with a history of car accident (five months before) was referred to our clinic because of shortness of breath. A holo-diastolic blowing murmur was heard on physical examination. Transesophageal echocardiography demonstrated severe aortic insufficiency secondary to rupture of the left coronary cusp associated with avulsion of aortic valve commissure. Conclusions: Since the aortic valve is rarely affected in blunt cardiac injury, it will be generally undiagnosed during the primary evaluation of a patient with blunt chest trauma. However, any patient presenting dyspnea after chest trauma should be examined for suspected aortic valve injury. PMID:25478541

  12. JAMA Patient Page: Heart Valve Infections

    MedlinePLUS

    ... by bacteria, though fungal infections can also occur. Prosthetic (replaced) or repaired heart valves are prone to ... of JAMA includes an article on infections of prosthetic heart valves. RISK FACTORS FOR MORE INFORMATION • American ...

  13. Geometry of aortic heart valves. [prosthetic design

    NASA Technical Reports Server (NTRS)

    Karara, H. M.

    1975-01-01

    Photogrammetric measurements of the surface topography of the aortic valves obtained from silicon rubber molds of freshly excised human aortic valves are presented. The data are part of an investigation into the design of a new prosthetic valve which will be a central-flow device, like the real valve and unlike previous central-occluding prostheses. Since the maximum stress on the heart valve is induced when the valve is closed and subject to diastolic back-pressure, it was decided to determine the valve geometry during diastole. That is, the molds were formed by pouring the rubber down the excised aortas, causing the valves to close. The molds were made under different pressures (20-120 torr); photogrammetry served as a vehicle for the assessment of the mold topography through the following outputs: digital models, surface profiles, and contour maps.

  14. Acoustic monitoring of power plant valves

    NASA Astrophysics Data System (ADS)

    Allen, J. W.; Hartman, W. F.; Robinson, J. C.

    1982-06-01

    Advanced surveillance diagnostics were applied to key nuclear power plant valves to improve the availability of the power plant. Two types of valves were monitored: boiling water reactor (BWR) three-stage, pilot-operated safety/relief valves and pressurized water reactor (PWR) feedwater control valves. Excessive leakage across the pilot-disc seat in BWR safety/relief valves can cause the second-stage pressure to reach the critical value that activates the valve, even though the set pressure was not exceeded. Acoustic emission created by the leak noise were monitored and calibrated to indicate incipient activation of the safety/relief valve. Hydrodynamic, vibration, control and process signals frm PWR feedwater control valves were monitored by a mini-computer based surveillance system.

  15. 14 CFR 27.995 - Fuel valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Fuel valves. 27.995 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...CATEGORY ROTORCRAFT Powerplant Fuel System Components § 27.995 Fuel valves. (a) There...

  16. 14 CFR 25.995 - Fuel valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Fuel valves. 25.995 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to...

  17. 14 CFR 29.995 - Fuel valves.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Fuel valves. 29.995 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...CATEGORY ROTORCRAFT Powerplant Fuel System Components § 29.995 Fuel valves. In addition to...

  18. Transapical transcatheter valve-in-valve replacement for deteriorated mitral valve bioprosthesis without radio-opaque indicators: the "invisible" mitral valve bioprosthesis.

    PubMed

    Rossi, Marco Luciano; Barbaro, Cristina; Pagnotta, Paolo; Cappai, Antioco; Ornaghi, Diego; Belli, Guido; Presbitero, Patrizia

    2015-02-01

    In view of the high number of bioprosthetic valves implanted during the past 30 years, an increasing number of patients are coming to medical attention because of degenerated bioprostheses. Transcatheter aortic valve-in-valve implantation has been described as a less invasive alternative to re-operation to treat severe structural valve deterioration. As far as degenerated mitral valve bioprostheses are concerned, transcatheter transapical mitral valve-in-valve replacement (TMVR) has been less commonly performed, but may also become a viable alternative to re-do replacement surgery. We describe treatment of a degenerated bioprosthetic mitral valve, characterised by complete absence of any radio-opaque landmarks making the TMVR procedure very challenging. PMID:25456504

  19. 49 CFR 195.420 - Valve maintenance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Valve maintenance. 195.420 Section... PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...Operation and Maintenance § 195.420 Valve maintenance. (a) Each...

  20. Non-collinear valve actuator

    NASA Technical Reports Server (NTRS)

    Richard, James A. (Inventor)

    2012-01-01

    A non-collinear valve actuator includes a primary actuating system and a return spring system with each applying forces to a linkage system in order to regulate the flow of a quarter-turn valve. The primary actuating system and return spring system are positioned non-collinearly, which simply means the primary actuating system and return spring system are not in line with each other. By positioning the primary actuating system and return spring system in this manner, the primary actuating system can undergo a larger stroke while the return spring system experiences significantly less displacement. This allows the length of the return spring to be reduced due to the minimization of displacement thereby reducing the weight of the return spring system. By allowing the primary actuating system to undergo longer strokes, the weight of the primary actuating system may also be reduced. Accordingly, the weight of the non-collinear valve actuator is reduced.

  1. Novel Active Combustion Control Valve

    NASA Technical Reports Server (NTRS)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  2. Fixed valve stem oil deflector

    SciTech Connect

    Stritzke, B.G.

    1988-09-27

    This patent describes an oil deflector for attachment to the valve guide of an internal combustion engine or the like comprising: a molded plastic cup having a generally cylindrical wall section and a transverse end wall, the end wall of the cup including an opening, a generally cylindrical seal element disposed in the opening in the cup. The seal element has an annular sealing lip on a radially inner surface thereof engageable with the stem of a valve of the engine in sliding relationship. The cylindrical wall portion of the deflector has axially extending circumferentially spaced fingers thereon with end portions, respectively, engageable with the valve guide to maintain the deflector in fixed relation thereto and sized so as to effect compression of the circular seal lip.

  3. Propellant isolation shutoff valve program

    NASA Technical Reports Server (NTRS)

    Merritt, F. L.

    1973-01-01

    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  4. Lost-motion valve actuator

    SciTech Connect

    Burris, W.J. III; Ringgenberg, P.D.

    1987-04-07

    A lost-motion valve actuator is described for a bore closure valve employed in a well bore, comprising: operating connector means adapted to move the bore closure valve between open and closed positions through longitudinal movement of the operating connector means. The operating connector means comprises an operating connector and a connector insert defining a recess therebetween; locking dog means comprising at least one locking dog received in the recess and spring biasing means adapted to urge at least one locking dog radially inwardly; and mandrel means slidably received within the operating connector means and including dog slot means associated therewith. The dog slot means comprises an annular slot on the exterior of the mandrel means adapted to lockingly receive at least one inwardly biased locking dog when proximate thereto, whereby longitudinal movement of the mandrel means is transmitted to the operating connector means.

  5. Recellularization of aortic valves in pigs

    Microsoft Academic Search

    Jesper Langhoff Honge; Jonas Funder; Erik Hansen; Pascal Maria Dohmen; Wolfgang Konertz; John Michael Hasenkam

    2011-01-01

    Objectives: Decellularized porcine heart valves treated with deoxycholic acid (DOA) have demonstrated complete recellularization and absence of calcification when implanted into the pulmonary position in sheep. We studied recellularization and calcification in stented DOA-treated heart valves compared with conventional stented glutaraldehyde-treated valves in the aortic position in juvenile pigs 6 months after implantation. Methods: DOA heart valves (n=12) and glutaraldehyde-treated

  6. Mechanics of the mitral valve

    PubMed Central

    Rausch, Manuel K.; Famaey, Nele; Shultz, Tyler O’Brien; Bothe, Wolfgang; Miller, D. Craig

    2013-01-01

    Alterations in mitral valve mechanics are classical indicators of valvular heart disease, such as mitral valve prolapse, mitral regurgitation, and mitral stenosis. Computational modeling is a powerful technique to quantify these alterations, to explore mitral valve physiology and pathology, and to classify the impact of novel treatment strategies. The selection of the appropriate constitutive model and the choice of its material parameters are paramount to the success of these models. However, the in vivo parameters values for these models are unknown. Here we identify the in vivo material parameters for three common hyperelastic models for mitral valve tissue, an isotropic one and two anisotropic ones, using an inverse finite element approach. We demonstrate that the two anisotropic models provide an excellent fit to the in vivo data, with local displacement errors in the sub-millimeter range. In a complementary sensitivity analysis, we show that the identified parameter values are highly sensitive to prestrain, with some parameters varying up to four orders of magnitude. For the coupled anisotropic model, the stiffness varied from 119,021kPa at 0% prestrain via 36kPa at 30% prestrain to 9kPa at 60% prestrain. These results may, at least in part, explain the discrepancy between previously reported ex vivo and in vivo measurements of mitral leaflet stiffness. We believe that our study provides valuable guidelines for modeling mitral valve mechanics, selecting appropriate constitutive models, and choosing physiologically meaningful parameter values. Future studies will be necessary to experimentally and computationally investigate prestrain, to verify its existence, to quantify its magnitude, and to clarify its role in mitral valve mechanics. PMID:23263365

  7. Tophaceous pseudogout of the mitral valve

    Microsoft Academic Search

    Marc R Moon; James I Fann; Prakash C Deedwania; Rollington Ferguson; Jon C Kosek; Thomas A Burdon

    1998-01-01

    This report describes a 61-year-old patient on chronic hemodialysis with multiple, left-sided, intracardiac masses causing intermittent coronary obstruction. Mitral valve replacement was performed. Massive deposition of calcium pyrophosphate crystals in and around the valve cusps led to the diagnosis of tophaceous pseudogout (tumoral calcinosis) of the mitral valve.

  8. Aspirator increases relief valve poppet stroke

    NASA Technical Reports Server (NTRS)

    Biddle, M. E.

    1967-01-01

    Addition of an aspirator to a relief valve increases the valve poppet stroke under dynamic flow conditions. The aspirator allows poppet inlet dynamic forces to overcome relief valve spring force. It reduces the fluid pressure in the skirt cavity by providing a low pressure sense probe.

  9. Dynamic Testing of Check Valves William Rahmeyer

    E-print Network

    Rahmeyer, William J.

    Dynamic Testing of Check Valves William Rahmeyer Professor of Civil and Environmental Engineering;1 DYNAMIC FLOW TESTING OF CHECK VALVES by William Rahmeyer, Professor of Civil and Environmental Engineering objectives of this paper are: (1) to present a test method by which check valves can be dynamically tested

  10. STATE OF CALIFORNIA VALVE LEAKAGE TEST

    E-print Network

    STATE OF CALIFORNIA VALVE LEAKAGE TEST CEC-MECH-8A (Revised 08/09) CALIFORNIA ENERGY COMMISSION CERTIFICATE OF ACCEPTANCE MECH-8A NA7.5.7 Valve Leakage Test (Page 1 of 3) Project Name/Address: System Name VALVE LEAKAGE TEST CEC-MECH-8A (Revised 08/09) CALIFORNIA ENERGY COMMISSION CERTIFICATE OF ACCEPTANCE

  11. 49 CFR 195.258 - Valves: General.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 3 2014-10-01 2014-10-01 false Valves: General. 195.258 Section 195.258 Transportation...LIQUIDS BY PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is...

  12. Automated Purge Valve Joseph Edward Farrell, III.

    E-print Network

    Wood, Stephen L.

    Automated Purge Valve by Joseph Edward Farrell, III. Bachelor of Science Marine Engineering the undersigned committee hereby approve the attached thesis Automated Purge Valve by Joseph Edward Farrell, III.D. Department Head Department of Marine and Environmental Systems #12;iii Abstract Title: Automated Purge Valve

  13. 14 CFR 27.995 - Fuel valves.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Fuel valves. 27.995 Section 27.995 Aeronautics...Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine...

  14. 49 CFR 229.109 - Safety valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Safety valves. 229.109 Section 229.109 ...Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity...

  15. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    ERIC Educational Resources Information Center

    Fornataro-Clerici, Lisa; Zajac, David J.

    1993-01-01

    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  16. Bone Formation and Inflammation in Cardiac Valves

    Microsoft Academic Search

    Emile R. Mohler III; Francis Gannon; Carol Reynolds; Robert Zimmerman; Martin G. Keane; Frederick S. Kaplan

    2010-01-01

    Background—For nearly a century, the mechanical failure of calcified heart valves was attributed to a passive degenerative process. Recently, several case reports described bone formation in surgically excised heart valves and suggested an unexpected process of tissue repair. Methods and Results—We studied the prevalence and pathology of heterotopic ossification in 347 surgically excised heart valves (256 aortic, 91 mitral) in

  17. 49 CFR 195.258 - Valves: General.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 3 2013-10-01 2013-10-01 false Valves: General. 195.258 Section 195.258 Transportation...LIQUIDS BY PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is...

  18. 49 CFR 229.109 - Safety valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Safety valves. 229.109 Section 229.109 ...Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity...

  19. 49 CFR 195.258 - Valves: General.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 3 2012-10-01 2012-10-01 false Valves: General. 195.258 Section 195.258 Transportation...LIQUIDS BY PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is...

  20. 49 CFR 195.258 - Valves: General.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 3 2011-10-01 2011-10-01 false Valves: General. 195.258 Section 195.258 Transportation...LIQUIDS BY PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is...

  1. 49 CFR 229.109 - Safety valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Safety valves. 229.109 Section 229.109 ...Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity...

  2. 14 CFR 27.995 - Fuel valves.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Fuel valves. 27.995 Section 27.995 Aeronautics...Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine...

  3. 14 CFR 27.995 - Fuel valves.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Fuel valves. 27.995 Section 27.995 Aeronautics...Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine...

  4. 49 CFR 229.109 - Safety valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Safety valves. 229.109 Section 229.109 ...Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity...

  5. 49 CFR 195.258 - Valves: General.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 3 2010-10-01 2010-10-01 false Valves: General. 195.258 Section 195.258 Transportation...LIQUIDS BY PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is...

  6. Compression release retarder with valve motion modifier

    SciTech Connect

    Meistrick, Z.S.; Quenneville, R.N.

    1987-11-17

    This patent describes an engine retarding system of a gas compression release type including an internal combustion engine having a pressurized lubricating oil system, intake valve means, exhaust valve means, and pushtube means associated with each of the intake valve means and exhaust valve means, hydraulically actuated slave piston means associated with the exhaust valve means to open the exhaust valve means at a predetermined time, control valve means and solenoid valve means communicating in series with the pressurized lubricating oil system and the hydraulically actuated slave piston means. The improvement comprises plenum means communicating with the slave piston means, first check valve means located between the slave piston means and the plenum, driving cylinder means communicating with the plenum, free piston means having first and second ends mounted for reciprocating motion in the driving cylinder means, spring means biasing the free piston means outwardly from the plenum. The free piston means communicate on the first end with the plenum means and first master cylinder means align with the exhaust valve pushtube means and communicate with the second end of the free piston means. First master piston means are mounted for reciprocatory motion in the first master cylinder means and adapted to be driven by the exhaust valve pushtube means, trigger check valve means aligned with the first master piston means and communicating between the slave piston means and the second side of the free piston means to permit flow of hydraulic fluid from the slave piston means toward the free piston means.

  7. Control Valves: International Site for Spirax Sarco

    NSDL National Science Digital Library

    This website contains a series of tutorials about flow control valve topics. The topics include capacity, sizing, valve types, characteristics, actuators, positioners, controllers and sensors. The website is broken down into five different sections covering everything from simply control valves themselves to the sensors which help to control these systems.

  8. Valve for fuel pin loading system

    DOEpatents

    Christiansen, D.W.

    1984-01-01

    A cyclone valve surrounds a wall opening through which cladding is projected. An axial valve inlet surrounds the cladding. Air is drawn through the inlet by a cyclone stream within the valve. An inflatable seal is included to physically engage a fuel pin subassembly during loading of fuel pellets.

  9. Improved fluid control valve extends diaphragm life

    NASA Technical Reports Server (NTRS)

    Mac Glashan, W. F.

    1965-01-01

    Wear resistance of flexible diaphragms in fluid control valves is increased by incorporating a soft rubber washer at the bottom of the piston, a flexible buffer between the diaphragm and the valve seat, and a fluid feedback arrangement. The stress and wear of components at the valve seat are minimized.

  10. How Is Heart Valve Disease Diagnosed?

    MedlinePLUS

    ... deposits are present in your heart. A chest x ray helps your doctor learn which type of valve defect you have, how severe it is, and ... and threaded to your heart. Your doctor uses x-ray images to guide the ... backflow is occurring through a valve and how fully the valve opens. You'll ...

  11. How Is Mitral Valve Prolapse Diagnosed?

    MedlinePLUS

    ... page from the NHLBI on Twitter. How Is Mitral Valve Prolapse Diagnosed? Mitral valve prolapse (MVP) most often is detected during a routine ... heart. Rate This Content: NEXT >> July 1, 2011 Mitral Valve Prolapse Clinical Trials Clinical trials are research studies that ...

  12. Cardiac valve replacement: Experience in 2400 patients

    PubMed Central

    Papo, Isidor; Albreht, Mis?a; Martinovi?, Nebojs?a; Sokoli?, Josip; Marenovi?, Tomislav

    1981-01-01

    In the series described here, 2400 patients over a 15-year period underwent surgery for correction of acquired valvular heart disease. Of these, 1586 patients had single valve replacement, 714 had double valve replacement, and 100 had triple valve replacement. Concomitant surgery for associated congenital and acquired lesions was done in 114 patients. The hospital mortality was 9.16%. PMID:15216220

  13. Probing the Effect of Structural Roughness on Domain Wall Formation in Spin Valves Using the Offspecular Reflectivity Technique

    Microsoft Academic Search

    Jun Park; Shannon M. Watson; Caitlin M. Furjanic; Dariya K. Draganova; Matthew J. Carey; Julie A. Borchers; Chih-Yung Chen; Patricia D. Sparks; James C. Eckert

    2008-01-01

    A previous polarized neutron reflectivity study of IrMn-based spin valves demonstrated that domain wall formation during training is influenced by the thickness of the ferromagnetic pinned layer. However, magnetoresistance measurements and x-ray reflectivity of spin valves with the same nominal structure revealed that sample roughness may also affect the characteristics of the exchange bias, and thus the type of domain

  14. Dynamic Simulations and an Adaptive Valve Timing Control for a Camless Engine Valve Actuator

    Microsoft Academic Search

    Kanghyun Nam

    Camless Engine Valve Actuation (CEVA) technologies have been known for improving fuel efficiency, enhancing power output, and reducing emissions of Internal Combustion(IC) engine. Electro-Hydraulic valve actuators are used to eliminate the camshaft of an existing Internal Combustion(IC) engine and to control the valve timing of intake and exhaust valves, valve duration independently. This paper presents a research activity like hydraulic

  15. Combined congenitally bicuspid aortic valve and mitral valve prolapse causing pure regurgitation

    PubMed Central

    Roberts, William C.; Zafar, Saleha; Ko, Jong Mi; Carry, Melissa M.; Hebeler, Robert F.

    2013-01-01

    Described herein is a patient with a purely regurgitant congenitally bicuspid aortic valve and a purely regurgitant prolapsing mitral valve. Although it is well established that the bicuspid aortic valve is a congenital anomaly, it is less well appreciated that mitral valve prolapse is almost certainly also a congenital anomaly. The two occurring in the same patient provides support that mitral valve prolapse is also a congenital anomaly. PMID:23382607

  16. Combined congenitally bicuspid aortic valve and mitral valve prolapse causing pure regurgitation.

    PubMed

    Roberts, William C; Zafar, Saleha; Ko, Jong Mi; Carry, Melissa M; Hebeler, Robert F

    2013-01-01

    Described herein is a patient with a purely regurgitant congenitally bicuspid aortic valve and a purely regurgitant prolapsing mitral valve. Although it is well established that the bicuspid aortic valve is a congenital anomaly, it is less well appreciated that mitral valve prolapse is almost certainly also a congenital anomaly. The two occurring in the same patient provides support that mitral valve prolapse is also a congenital anomaly. PMID:23382607

  17. Impact wear testing of diamond-like carbon films for engine valve-tappet surfaces

    Microsoft Academic Search

    S. D. A. Lawes; S. V. Hainsworth; M. E. Fitzpatrick

    2010-01-01

    There is a strong drive to reduce the energy losses from automotive engines in order to improve fuel economy and reduce emissions of pollutants. The demands of reducing engine losses are pushing engine manufacturers to consider using technologies such as diamond-like carbon (DLC) coatings to give enhanced wear protection of components and provide low friction operation. Valve-train component interactions are

  18. Extreme precipitation event over North China in August 2010: observations, monthly forecasting, and link to intra-seasonal variability of the Silk-Road wave-train across Eurasia

    NASA Astrophysics Data System (ADS)

    Orsolini, Yvan; Zhang, Ling; Peters, Dieter; Fraedrich, Klaus

    2014-05-01

    Forecast of regional precipitation events at the sub-seasonal timescale remains a big challenge for operational global prediction systems. Over the Far East in summer, climate and precipitation are strongly influenced by the fluctuating western Pacific subtropical high (WPSH) and strong precipitation is often associated with southeasterly low-level wind that brings moist-laden air from the southern China seas. The WPSH variability is partly influenced by quasi-stationary wave-trains propagating eastwards from Europe across Asia along the two westerly jets: the Silk-Road wave-train along the Asian jet at mid-latitudes and, on a more northern route, the polar wave-train along the sub-polar jet. While the Silk-Road wave-train appears as a robust, internal mode of variability in seasonal predictions models, its predictability is very low on the sub-seasonal to seasonal time scale. A case in point is the unusual summer of 2010, when China experienced its worst seasonal flooding for a decade, triggered by unusually prolonged and severe monsoonal rains. In addition that summer was also characterized by record-breaking heat wave over Eastern Europe and Russia as well as catastrophic monsoonal floods in Pakistan 2010. The impact of the latter circulation anomalies on the precipitation further east over China, has been little explored. Here, we examine the role and the actual predictability of the Silk-Road wave-train, and its impact on precipitation over Northeastern China throughout August 2010, using the high-resolution IFS forecast model of ECMWF, realistic initialized and run in an ensemble mode. We demonstrate that the forecast failure with regard to flooding and extreme precipitation over Northeastern China in August 2010 is linked to the failure to represent intra-seasonal variations of the Silk-Road wave-train and the associated intensification of the WPSH.

  19. Pressure relief valve/safety relief valve testing

    SciTech Connect

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

    1994-02-01

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

  20. Dynamic shape modeling of the mitral valve from real-time 3D ultrasound images using continuous medial representation

    NASA Astrophysics Data System (ADS)

    Pouch, Alison M.; Yushkevich, Paul A.; Jackson, Benjamin M.; Gorman, Joseph H., III; Gorman, Robert C.; Sehgal, Chandra M.

    2012-03-01

    Purpose: Patient-specific shape analysis of the mitral valve from real-time 3D ultrasound (rt-3DUS) has broad application to the assessment and surgical treatment of mitral valve disease. Our goal is to demonstrate that continuous medial representation (cm-rep) is an accurate valve shape representation that can be used for statistical shape modeling over the cardiac cycle from rt-3DUS images. Methods: Transesophageal rt-3DUS data acquired from 15 subjects with a range of mitral valve pathology were analyzed. User-initialized segmentation with level sets and symmetric diffeomorphic normalization delineated the mitral leaflets at each time point in the rt-3DUS data series. A deformable cm-rep was fitted to each segmented image of the mitral leaflets in the time series, producing a 4D parametric representation of valve shape in a single cardiac cycle. Model fitting accuracy was evaluated by the Dice overlap, and shape interpolation and principal component analysis (PCA) of 4D valve shape were performed. Results: Of the 289 3D images analyzed, the average Dice overlap between each fitted cm-rep and its target segmentation was 0.880+/-0.018 (max=0.912, min=0.819). The results of PCA represented variability in valve morphology and localized leaflet thickness across subjects. Conclusion: Deformable medial modeling accurately captures valve geometry in rt-3DUS images over the entire cardiac cycle and enables statistical shape analysis of the mitral valve.

  1. Available transcatheter aortic valve replacement technology.

    PubMed

    Weiss, Dillon; Ruiz, Carlos E; Pirelli, Luigi; Jelnin, Vladimir; Fontana, Gregory P; Kliger, Chad

    2015-03-01

    Transcatheter aortic valve replacement (TAVR) is an alternative and now recommended therapy for patients who meet indications for surgical valve replacement and are high or prohibitive surgical risk. Available TAVR technologies are rapidly emerging to treat this complex patient population. This review discusses the specific valve designs of the transcatheter heart valves currently used, newer generation modifications to overcome limitations of earlier valve designs, and novel imaging modalities, such as computed tomographic angiography-fluoroscopy and echocardiography-fluoroscopy fusion imaging, available for pre-procedural planning and intra-procedural guidance. PMID:25651785

  2. Dual rate pressure relief valve

    NASA Technical Reports Server (NTRS)

    Steeneken, J.

    1968-01-01

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

  3. Inlet Flow Valve Engine Analyses

    NASA Technical Reports Server (NTRS)

    Champagne, G. A.

    2004-01-01

    Pratt&Whitney, under Task Order 13 of the NASA Large Engine Technology (LET) Contract, conducted a study to determine the operating characteristics, performance and weights of Inlet Flow Valve (IFV) propulsion concepts for a Mach 2.4 High Speed Civil Transport (HSCT).

  4. Hydraulic servo control spool valve

    DOEpatents

    Miller, Donald M. (Sunnyside, WA)

    1983-01-01

    A servo operated spool valve having a fixed sleeve and axially movable spool. The sleeve is machined in two halves to form a long, narrow tapered orifice slot across which a transverse wall of the spool is positioned. The axial position of the spool wall along the slot regulates the open orifice area with extreme precision.

  5. Living with Mitral Valve Prolapse

    MedlinePLUS

    ... Clinical Trials Links Related Topics Arrhythmia Endocarditis Heart Valve Disease How the Heart Works Marfan Syndrome Send a link to NHLBI to someone by E-MAIL | PRINT | SHARE this page from the NHLBI BOOKMARK & SHARE X Share this page from the NHLBI on Blogger. ...

  6. Bicuspid aortic valve is heritable

    Microsoft Academic Search

    Linda Cripe; Gregor Andelfinger; Lisa J. Martin; Kerry Shooner; D. Woodrow Benson

    2004-01-01

    ObjectivesPrevious studies have established familial clustering of bicuspid aortic valve (BAV), presumably indicating genetic inheritance. Our objective was to statistically test whether the segregation pattern of BAV is consistent with genetic inheritance and to obtain an estimate of the size of the genetic effect (heritability).

  7. Microprocessor-Based Valved Controller

    NASA Technical Reports Server (NTRS)

    Norman, Arnold M., Jr.

    1987-01-01

    New controller simpler, more precise, and lighter than predecessors. Mass-flow controller compensates for changing supply pressure and temperature such as occurs when gas-supply tank becomes depleted. By periodically updating calculation of mass-flow rate, controller determines correct new position for valve and keeps mass-flow rate nearly constant.

  8. Manufacturable plastic microfluidic valves using thermal actuation.

    PubMed

    Pitchaimani, Karthik; Sapp, Brian C; Winter, Adam; Gispanski, Austin; Nishida, Toshikazu; Hugh Fan, Z

    2009-11-01

    A low-cost, manufacturable, thermally actuated, plastic microfluidic valve has been developed. The valve contains an encapsulated, temperature-sensitive fluid, which expands, deflecting a thin elastomeric film into a fluidic channel to control fluid flow. The power input for thermal expansion of each microfluidic valve can be controlled using a printed circuit board (PCB)-based controller, which is suitable for mass production and large-scale integration. A plastic microfluidic device with such valves was fabricated using compression molding and thermal lamination. The operation of the valves was investigated by measuring a change in the microchannel's ionic conduction current mediated by the resistance variation corresponding to the deflection of the microvalve. Valve closing was also confirmed by the disappearance of fluorescence when a fluorescent solution was displaced in the valve region. Valve operation was characterized for heater power ranging from 36 mW to 80 mW. When the valve was actuating, the local channel temperature was 10 to 19 degrees C above the ambient temperature depending on the heater power used. Repetitive valve operations (up to 50 times) have been demonstrated with a flow resulting from a hydrostatic head. Valve operation was tested for a flow rate of 0.33-4.7 microL/min. PMID:19823723

  9. Solar energy operated irrigation surge valve

    SciTech Connect

    Spain, R. L.

    1985-08-20

    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 slowly shift the valve disc from one seat toward engagement with the other seat. The drive mechanism includes a reversible electric motor, a timer, a storage battery and a solar panel for recharging the storage battery. The timer alternately operates the motor in opposite directions whereby the valve disc is shifted back and forth between seated engagement with the axially spaced valve seats.

  10. Dual motion valve with single motion input

    NASA Technical Reports Server (NTRS)

    Belew, Robert (inventor)

    1987-01-01

    A dual motion valve includes two dual motion valve assemblies with a rotary input which allows the benefits of applying both rotary and axial motion to a rotary sealing element with a plurality of ports. The motion of the rotary sealing element during actuation provides axial engagement of the rotary sealing element with a stationary valve plate which also has ports. Fluid passages are created through the valve when the ports of the rotary sealing element are aligned with the ports of the stationary valve plate. Alignment is achieved through rotation of the rotary sealing element with respect to the stationary valve plate. The fluid passages provide direct paths which minimize fluid turbulence created in the fluid as it passes through the valve.

  11. Emerging trends in heart valve engineering: Part II. Novel and standard technologies for aortic valve replacement.

    PubMed

    Kheradvar, Arash; Groves, Elliott M; Goergen, Craig J; Alavi, S Hamed; Tranquillo, Robert; Simmons, Craig A; Dasi, Lakshmi P; Grande-Allen, K Jane; Mofrad, Mohammad R K; Falahatpisheh, Ahmad; Griffith, Boyce; Baaijens, Frank; Little, Stephen H; Canic, Suncica

    2015-04-01

    The engineering of technologies for heart valve replacement (i.e., heart valve engineering) is an exciting and evolving field. Since the first valve replacement, technology has progressed by leaps and bounds. Innovations emerge frequently and supply patients and physicians with new, increasingly efficacious and less invasive treatment options. As much as any other field in medicine the treatment of heart valve disease has experienced a renaissance in the last 10 years. Here we review the currently available technologies and future options in the surgical and transcatheter treatment of aortic valve disease. Different valves from major manufacturers are described in details with their applications. PMID:25449148

  12. Everlasting sliding-disc valve. METC SOA test valve No. B3, State-of-the-art lockhopper valve testing and development project. Summary test report

    Microsoft Academic Search

    J. F. Gardner; R. C. Hall; R. G. Hornbeck; R. A. Griffith; T. M. Yost; D. M. Harvey; W. E. Galvin; T. R. Gayheart; S. K. Kapur

    1980-01-01

    The Everlasting Sliding-Disc Valve (METC SOA Test Valve No. B-3) accumulated 740 valve cycles in the Valve Static Test Unit and over 16,000 valve cycles in the Valve Dynamic Test Unit. Only minor operating problems, primarily erratic motion and some scoring of the seating surface, where encountered with coarse limestone (5\\/16'' x 1\\/8'') particles. Operation with fine solids (100-mesh limestone)

  13. Living-Engineered Valves for Transcatheter Venous Valve Repair

    PubMed Central

    Weber, Benedikt; Robert, Jérôme; Ksiazek, Agnieszka; Wyss, Yves; Frese, Laura; Slamecka, Jaroslav; Kehl, Debora; Modregger, Peter; Peter, Silvia; Stampanoni, Marco; Proulx, Steven; Falk, Volkmar

    2014-01-01

    Background: Chronic venous insufficiency (CVI) represents a major global health problem with increasing prevalence and morbidity. CVI is due to an incompetence of the venous valves, which causes venous reflux and distal venous hypertension. Several studies have focused on the replacement of diseased venous valves using xeno- and allogenic transplants, so far with moderate success due to immunologic and thromboembolic complications. Autologous cell-derived tissue-engineered venous valves (TEVVs) based on fully biodegradable scaffolds could overcome these limitations by providing non-immunogenic, non-thrombogenic constructs with remodeling and growth potential. Methods: Tri- and bicuspid venous valves (n=27) based on polyglycolic acid–poly-4-hydroxybutyrate composite scaffolds, integrated into self-expandable nitinol stents, were engineered from autologous ovine bone-marrow-derived mesenchymal stem cells (BM-MSCs) and endothelialized. After in vitro conditioning in a (flow) pulse duplicator system, the TEVVs were crimped (n=18) and experimentally delivered (n=7). The effects of crimping on the tissue-engineered constructs were investigated using histology, immunohistochemistry, scanning electron microscopy, grating interferometry (GI), and planar fluorescence reflectance imaging. Results: The generated TEVVs showed layered tissue formation with increasing collagen and glycosaminoglycan levels dependent on the duration of in vitro conditioning. After crimping no effects were found on the MSC level in scanning electron microscopy analysis, GI, histology, and extracellular matrix analysis. However, substantial endothelial cell loss was detected after the crimping procedure, which could be reduced by increasing the static conditioning phase. Conclusions: Autologous living small-diameter TEVVs can be successfully fabricated from ovine BM-MSCs using a (flow) pulse duplicator conditioning approach. These constructs hold the potential to overcome the limitations of currently used non-autologous replacement materials and may open new therapeutic concepts for the treatment of CVI in the future. PMID:24156382

  14. SU-C-18C-02: Specifcation of X-Ray Projection Angles Which Are Aligned with the Aortic Valve Plane From a Planar Image of a Valvuloplasty Balloon Inflated Across the Aortic Valve

    SciTech Connect

    Fetterly, K; Mathew, V [Mayo Clinic, Rochester, MN (United States)

    2014-06-01

    Purpose: Transcatheter aortic valve replacement (TAVR) procedures provide a method to implant a prosthetic aortic valve via a minimallyinvasive, catheter-based procedure. TAVR procedures require use of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane to minimize prosthetic valve positioning error due to x-ray imaging parallax. The purpose of this work is to calculate the continuous range of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane from a single planar image of a valvuloplasty balloon inflated across the aortic valve. Methods: Computational methods to measure the 3D angular orientation of the aortic valve were developed. Required inputs include a planar x-ray image of a known valvuloplasty balloon inflated across the aortic valve and specifications of x-ray imaging geometry from the DICOM header of the image. A-priori knowledge of the species-specific typical range of aortic orientation is required to specify the sign of the angle of the long axis of the balloon with respect to the x-ray beam. The methods were validated ex-vivo and in a live pig. Results: Ex-vivo experiments demonstrated that the angular orientation of a stationary inflated valvuloplasty balloon can be measured with precision less than 1 degree. In-vivo pig experiments demonstrated that cardiac motion contributed to measurement variability, with precision less than 3 degrees. Error in specification of x-ray geometry directly influences measurement accuracy. Conclusion: This work demonstrates that the 3D angular orientation of the aortic valve can be calculated precisely from a planar image of a valvuloplasty balloon inflated across the aortic valve and known x-ray geometry. This method could be used to determine appropriate c-arm angular projections during TAVR procedures to minimize x-ray imaging parallax and thereby minimize prosthetic valve positioning errors.

  15. Aerosol penetration through respirator exhalation valves.

    PubMed

    Bellin, P; Hinds, W C

    1990-10-01

    Exhalation valves are a critical component of industrial respirators. They are designed to permit minimal inward leakage of air contaminants during inhalation and provide low resistance during exhalation. Under normal conditions, penetration of aerosol through exhalation valves is minimal. The exhalation valve is, however, a vulnerable component of a respirator and under actual working conditions may become dirty or damaged to the point of causing significant leakage. Aerosol penetration was measured for normal exhalation valves and valves compromised by paint or fine copper wires on the valve seat. Penetration increased with increasing wire diameter. A wire 250 microns in diameter allowed greater than 1% penetration into the mask cavity. Dirt or paint accumulated on the exhalation valve allowed a similar level of penetration. Work rate had little effect on observed penetration. Penetration decreased significantly with increasing aerosol particle size. The amount of material on the valve or valve seat necessary for significant (greater than 0.5%) inward leakage in a half-mask respirator could be readily observed by careful inspection of the exhalation valve and its seat in good lighting conditions. PMID:2147535

  16. Leakage test during mitral valve repair.

    PubMed

    Watanabe, Taiju; Arai, Hirokuni

    2014-11-01

    Mitral valve repair is the preferred surgical treatment for mitral regurgitation. Cardiac surgeons must increasingly pursue high-quality mitral valve repair, which ensures excellent long-term outcomes. Intraoperative assessment of a competency of the repaired mitral valve before closure of the atrium is an important step in accomplishing successful mitral valve repair. Saline test is the most simple and popular method to evaluate the repaired valve. In addition, an "Ink test" can provide confirmation of the surface of coaptation, which is often insufficient in the assessment of saline test. There are sometimes differences between the findings of the leakage test in an arrested heart and the echocardiographic findings after surgery. Assessment of the mitral valve in an arrested heart may not accurately reflect its function in a contractile heart. Assessment of the valve on the beating heart induced by antegrade or retrograde coronary artery perfusion can provide a more physiological assessment of the repaired valve. Perfusion techniques during beating heart surgery mainly include antegrade coronary artery perfusion without aortic cross-clamping, and retrograde coronary artery perfusion via the coronary sinus with aortic cross-clamping. It is the most important point for the former approach to avoid air embolism with such precaution as CO2 insufflation, left ventricular venting, and transesophageal echocardiography, and for the latter approach to maintain high perfusion flow rate of coronary sinus and adequate venting. Leakage test during mitral valve repair increasingly takes an important role in successful mitral valve reconstruction. PMID:25156036

  17. Factors associated with moderate or severe left atrioventricular valve regurgitation within 30 days of repair of incomplete atrioventricular septal defect

    PubMed Central

    Kozak, Marcelo Felipe; Kozak, Ana Carolina Leiroz Ferreira Botelho Maisano; Marchi, Carlos Henrique De; de Godoy, Moacyr Fernandes; Croti, Ulisses Alexandre; Moscardini, Airton Camacho

    2015-01-01

    Introduction Left atrioventricular valve regurgitation is the most concerning residual lesion after surgical correction of atrioventricular septal defect. Objective To determine factors associated with moderate or greater left atrioventricular valve regurgitation within 30 days of surgical repair of incomplete atrioventricular septal defect. Methods We assessed the results of 51 consecutive patients 14 years-old and younger presenting with incomplete atrioventricular septal defect that were operated on at our practice between 2002 and 2010. The following variables were considered: age, weight, absence of Down syndrome, grade of preoperative left atrioventricular valve regurgitation, abnormalities on the left atrioventricular valve and the use of annuloplasty. The median age was 4.1 years; the median weight was 13.4 Kg; 37.2% had Down syndrome. At the time of preoperative evaluation, there were 23 cases with moderate or greater left atrioventricular valve regurgitation (45.1%). Abnormalities on the left atrioventricular valve were found in 17.6%; annuloplasty was performed in 21.6%. Results At the time of postoperative evaluation, there were 12 cases with moderate or greater left atrioventricular valve regurgitation (23.5%). The variation between pre- and postoperative grades of left atrioventricular valve regurgitation of patients with atrioventricular valve malformation did not reach significance (P=0.26), unlike patients without such abnormalities (P=0.016). During univariate analysis, only absence of Down syndrome was statistically significant (P=0.02). However, after a multivariate analysis, none of the factors reached significance. Conclusion None of the factors studied was determinant of a moderate or greater left atrioventricular valve regurgitation within the first 30 days of repair of incomplete atrioventricular septal defect in the sample. Patients without abnormalities on the left atrioventricular valve benefit more of the operation.

  18. Mathematical multi-scale model of the cardiovascular system including mitral valve dynamics. Application to ischemic mitral insufficiency

    PubMed Central

    2011-01-01

    Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS) model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV) loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves. PMID:21942971

  19. Trilogy Pericardial Valve: Hemodynamic Performance and Calcification in Adolescent Sheep

    Microsoft Academic Search

    Willem Flameng; Bart Meuris; Crystal Cunanan; Erik Verbeken; Paul Herijgers; Marie-Christine Herregods

    2010-01-01

    Background. We assessed the hemodynamic perfor- mance and calcification potential of a new design o f bovine pericardial valve, the Trilogy valve (Arbor Surgi - cal Technologies Inc, Irvine, CA). We compared this new valve with the Perimount valve (Edwards Lifesciences , Irvine, CA) in a randomized prospective study in adoles - cent sheep . Methods. Nine Trilogy valves (size

  20. Cryogenic leak testing of tube fittings/valves

    NASA Technical Reports Server (NTRS)

    Jia, L. X.; Moslemian, D.; Chow, W. L.

    1992-01-01

    A high pressure and variable temperature cryogenic leak testing system was conceived and designed in order to conduct leakage testing of pipe fittings/valves in liquid hydrogen supply lines of the Space Shuttle. The system can create a continuous testing environment of variable temperature, 5.5 to about 300 K, and variable pressure, 0.01 to about 70 x 10 exp 5 Pa, with a large sample space, 90 mm diameter x 228 mm length, and at low operating cost. In terms of cryogenic leak testing the system has a special capability for extensive applications. The system comprised a variable temperature cryostat, a high pressure sample chamber, a vacuum pumping station, gas flow control system, pressure and temperature control systems, and leak detecting and measuring systems. A general discussion of cryogenic leak testing methods is also presented.

  1. Variable-capacity turbocharger

    SciTech Connect

    Houkita, A.; Hokari, T.

    1987-09-01

    A variable-capacity turbocharger is described comprising: (a) a turbine casing having a turbine inlet portion, a turbine outlet portion and a scroll chamber; (b) a turbine impeller located in the scroll chamber and having a multiplicity of blades; (c) a partition wall extending to the vicinity of the turbine inlet portion to partition the scroll chamber into a first scroll chamber and a second scroll chamber and to define a first exhaust introducing passageway and a second exhaust introducing passageway for introducing exhaust gases separately into the first scroll chamber and second chamber respectively; (d) exhaust flow control valve means located at least in the second exhaust introducing passageway and opening in the direction of flow of the exhaust gases; and (e) valve set means formed separately from the turbine casing and located in the turbine inlet portion, the valve seat means cooperating with the exhaust flow control valve means to control the flowrate of exhaust gases flowing into the second exhaust introducing passageway.

  2. Mechanical Prosthetic Valves and Pregnancy

    PubMed Central

    Panduranga, Prashanth; El-Deeb, Mohammed; Jha, Chitra

    2014-01-01

    Choosing the best anticoagulant therapy for a pregnant patient with a mechanical prosthetic valve is controversial and the published international guidelines contain no clear-cut consensus on the best approach. This is due to the fact that there is presently no anticoagulant which can reliably decrease thromboembolic events while avoiding damage to the fetus. Current treatments include either continuing oral warfarin or substituting warfarin for subcutaneous unfractionated heparin or low-molecular-weight heparin (LMWH) in the first trimester (6–12 weeks) or at any point throughout the pregnancy. However, LMWH, while widely-prescribed, requires close monitoring of the blood anti-factor Xa levels. Unfortunately, facilities for such monitoring are not universally available, such as within hospitals in developing countries. This review evaluates the leading international guidelines concerning anticoagulant therapy in pregnant patients with mechanical prosthetic valves as well as proposing a simplified guideline which may be more relevant to hospitals in this region. PMID:25364545

  3. Electronically Variable Pressure Regulator (EVPR)

    Microsoft Academic Search

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

    1989-01-01

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

  4. Miniaturized double latching solenoid valve

    NASA Technical Reports Server (NTRS)

    Smith, James T. (Inventor)

    2010-01-01

    A valve includes a generally elongate pintle; a spacer having a rounded surface that bears against the pintle; a bulbous tip fixed to the spacer; and a hollow, generally cylindrical collar fixed to the pintle, the collar enclosing the spacer and the tip and including an opening through which a portion of the tip extends, the opening in the collar and interior of the collar being of a size such that the tip floats therein.

  5. Force measuring valve assemblies, systems including such valve assemblies and related methods

    DOEpatents

    DeWall, Kevin George (Pocatello, ID); Garcia, Humberto Enrique (Idaho Falls, ID); McKellar, Michael George (Idaho Falls, ID)

    2012-04-17

    Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

  6. 100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE ...

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

    100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE FOR RAPID-LOAD LIQUID OXYGEN TANK - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  7. Oil well pump traveling valve

    SciTech Connect

    Blassingame, D.L.

    1988-05-03

    A traveling valve for a sucker rod operated oil well pump having a standing valve and a working barrel is described comprising: pump head means vertically reciprocated by the depending end of the sucker rod and having a depending tubular end portion provided with fluid outlet ports; first sleeve means depending from the tubular end portion for forming a fluid passageway therewith; second sleeve means surrounding the first sleeve means for connecting the pump head to the working barrel, crosshead means including a generally rectangular crosshead extending transversely through the first sleeve means and connecting the first sleeve means to the second sleeve means by its respective end surfaces confronting the inner wall surface of the second sleeve means through the respective first sleeve slot; an outstanding pin on each end of the crosshead and projecting through the wall of the second sleeve means; and, valve means tethered in the first sleeve means for opening and closing the fluid passageway in response to and in cooperative sequence with the reciprocating fluid pumping movement of the first sleeve means.

  8. In vitro balloon dilatation of mitral valve stenosis: the importance of subvalvar involvement as a cause of mitral valve insufficiency

    Microsoft Academic Search

    A S Sadee; A E Becker

    1991-01-01

    To investigate the mechanism that increases the orifice area of the mitral valve during balloon dilatation 43 surgically excised intact rheumatic mitral valves were studied. The main pathological features were (a) fibrosis of mitral valve leaflets and commissures (10 valves); (b) fibrosis with calcification of one commissure (eight anterolateral, seven posteromedial); (c) fibrosis with calcification of both commissures (seven valves);

  9. Wavelet analysis of valve closing sound detects malfunction of bileaflet mechanical valve

    Microsoft Academic Search

    Hiroshi Sugiki; Toshifumi Murashita; Norihiko Shiiya; Yoshiro Matsui; Kenji Sugiki

    2008-01-01

    Several studies have reported the asynchronous closure of normal bileaflet valves (NBVs), resulting in a split in its closing\\u000a sound; however, the clinical significance of this split has never been studied in malfunctioning bileaflet valves (MBVs).\\u000a The study comprised 218 valves in 184 patients, including normal monoleaflet valves (n = 10), NBVs (n = 198), and MBVs (n = 10).

  10. Venous Hypertension, Inflammation and Valve Remodeling

    Microsoft Academic Search

    S. Takase; L. Pascarella; L. Lerond; J. J. Bergan; G. W. Schmid-Schönbein

    2004-01-01

    Objectives. To identify possible mechanisms for destruction of valves in chronic venous hypertension and the results of treatment with an anti-inflammatory micronized purified flavonoid fraction.Material and methods. The saphenous vein valves in a rat model of venous hypertension caused by a femoral arterial-venous fistula were studied. Studies included femoral venous pressure, valve morphology, femoral venous reflux and selected molecular inflammatory

  11. Transcriptional Regulation of Heart Valve Progenitor Cells

    Microsoft Academic Search

    Santanu Chakraborty; Michelle D. Combs; Katherine E. Yutzey

    2010-01-01

    The development and normal function of the heart valves requires complex interactions among signaling molecules, transcription\\u000a factors and structural proteins that are tightly regulated in time and space. Here we review the roles of critical transcription\\u000a factors that are required for specific aspects of normal valve development. The early progenitors of the heart valves are\\u000a localized in endocardial cushions that

  12. Prosthetic heart valves: catering for the few.

    PubMed

    Zilla, Peter; Brink, Johan; Human, Paul; Bezuidenhout, Deon

    2008-02-01

    Prosthetic heart valves epitomize both the triumphant advance of cardiac surgery in its early days and its stagnation into a retrospective, exclusive first world discipline of late. Fifty-two years after the first diseased heart valve was replaced in a patient, prostheses largely represent the concepts of the 1960s with many of their design-inherent complications. While the sophisticated medical systems of the developed world may be able to cope with sub-optimal replacements, these valves are poorly suited to the developing world (where the overwhelming majority of potential valve recipients reside), due to differences in age profiles and socio-economic circumstances. Therefore, it is the latter group which suffered most from the sluggish pace of developments. While it previously took less than 7 years for mechanical heart valves to develop from the first commercially available ball-in-cage valve to the tilting pyrolytic-carbon disc valve, and another 10 years to arrive at the all-carbon bi-leaflet design, only small incremental improvements have been achieved since 1977. Similarly, bioprosthetic valves saw their last major break-through development in the late 1960s when formalin fixation was replaced by glutaraldehyde cross linking. Since then, poorly understood so-called 'anti-calcification' treatments were added and the homograft concept rediscovered under the catch-phrase 'stentless'. Still, tissue valves continue to degenerate fast in younger patients, making them unsuitable for developing countries. Yet, catheter-delivered prostheses almost exclusively use bioprosthetic tissue, thereby reducing one of the most promising developments for patients of the developing world into a fringe product for the few first world recipients. With tissue-engineered valves aiming at the narrow niche of congenital malformations and synthetic flexible leaflet valves being in their fifth decade of low-key development, heart valve prostheses seem to be destined to remain an unsatisfying and exclusive first world solution for a long time to come. PMID:17950840

  13. Propellant actuated nuclear reactor steam depressurization valve

    DOEpatents

    Ehrke, Alan C. (San Jose, CA); Knepp, John B. (San Jose, CA); Skoda, George I. (Santa Clara, CA)

    1992-01-01

    A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

  14. The Long-Term Outcome of Posterior Urethral Valves Treated with Primary Valve Ablation and Observation

    Microsoft Academic Search

    Grahame H. H. Smith; Douglas A. Canning; Seth L. Schulman; Howard M. Snyder; John W. Duckett

    1996-01-01

    PurposeWe believe that primary valve ablation with observation is the preferred management for posterior urethral valves. However, debate continues as to the role of high diversion. We examined the long-term outcome of a large series of patients treated with primary valve ablation, and compared it to the outcome of high diversion and vesicostomy.

  15. Mechanical heart valves, specifically bileaflet valves, are widely used to replace diseased native

    E-print Network

    Manning, Keefe B.

    studied in vitro using flow visualization, ultrasound techniques, and laser Doppler velocimetry under840 Mechanical heart valves, specifically bileaflet valves, are widely used to replace diseased or regurgitant flow must be particularly scrutinized to assess its impact on mechanical heart valve function

  16. Mitral Valve Prolapse with Rigid Annular Calcifications: A New Technique for Mitral Valve Replacement

    PubMed Central

    Wallsh, Eugene; Franzone, Andrew; Weinstein, Gerald; Bruno, Peter; Rossi, Peter

    1985-01-01

    Severe calcification of the mitral annulus presents a technical challenge in valve replacement, and in the case reported here, we replaced the valve with a new technique. Employing a rim of tissue created from the supra-annular left atrium imbricated to the edge of the posterior mitral leaflet, we created a substitute “annulus” for prosthetic valve fixation. Images PMID:15226981

  17. Transcatheter aortic valve implantation in Jehovah's Witness patients with symptomatic severe aortic valve stenosis

    PubMed Central

    Buz, Semih; Pasic, Miralem; Unbehaun, Axel; Hetzer, Roland

    2012-01-01

    Transcatheter aortic valve implantation (TAVI) is currently reserved for high or prohibitive surgical-risk patients with aortic valve stenosis. We report on successful TAVI in two Jehovah's witness patients. It offers a simple and effective treatment of severe aortic valve stenosis in high-risk patients who refuse the use of allogeneic blood and blood products. PMID:22753437

  18. A FAST OPENING TOROIDAL GAS VALVE

    SciTech Connect

    Myers, B.R.; Levine, M.A.; Shaw, R.S.

    1980-02-01

    A pulsed toroidal gas valve is described. The valve, which has a 10-cm aperture through the center, is designed to be used in toroidal plasma experiments where current-carrying conductors must pass through the axis of symmetry. The valve uses a coil and magnetic flux concentrator to displace an aluminum diaphragm by magnetic forces. Upon energizing the coil, the diaphragm opens in a few tens of microseconds and releases the gas (hydrogen) contained in a toroidal plenum. The resulting gas distribution outside the valve contains up to 10{sup 19}H{sub 2} molecules and has a high degree of toroidal symmetry.

  19. Current Status of Prosthetic Cardiac Valves

    PubMed Central

    Huse, Wilfred M.; Wareham, Ellsworth E.

    1967-01-01

    The majority of patients with acquired valvular heart disease have severe damage to valves which is not amenable to repair but can now be treated by valve replacement with an acceptable mortality and morbidity. The caged ball or disc valve is widely used and is proving clinically satisfactory for cardiac valve replacement. Thromboembolism is the significant complication. With improvement in technique the incidence of infection, detachment and other complications has been reduced. ImagesFigure 1.Figure 2.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9.Figure 10. PMID:6039188

  20. A Quantitative Approach to the Intraoperative Echocardiographic Assessment of the Mitral Valve for Repair.

    PubMed

    Mahmood, Feroze; Matyal, Robina

    2015-07-01

    Intraoperative echocardiography of the mitral valve has evolved from a qualitative assessment of flow-dependent variables to quantitative geometric analyses before and after repair. In addition, 3-dimensional echocardiographic data now allow for a precise assessment of mitral valve apparatus. Complex structures, such as the mitral annulus, can be interrogated comprehensively without geometric assumptions. Quantitative analyses of mitral valve apparatus are particularly valuable for identifying indices of left ventricular and mitral remodeling to establish the chronicity and severity of mitral regurgitation. This can help identify patients who may be unsuitable candidates for repair as the result of irreversible remodeling of the mitral valve apparatus. Principles of geometric analyses also have been extended to the assessment of repaired mitral valves. Changes in mitral annular shape and size determine the stress exerted on the mitral leaflets and, therefore, the durability of repair. Given this context, echocardiographers may be expected to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success and failure of the repair procedure. As a result, anesthesiologists have progressed from being mere service providers to participants in the decision-making process. It is therefore prudent for them to acquaint themselves with the principles of intraoperative quantitative mitral valve analysis to assist in rational and objective decision making. PMID:26086507

  1. 49 CFR 179.400-19 - Valves and gages.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Valves and gages. 179.400-19...TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless...107A) § 179.400-19 Valves and gages. (a) Valves. Manually operated...

  2. D0 Silicon Upgrade: Control Dewar Valve Calculations

    SciTech Connect

    Rucinski, Russ; /Fermilab

    1995-10-20

    This engineering note documents the calculations that were done to support the valve size selection for the magnet flow control valve, EVMF in the solenoid control dewar. The size selected was a control valve with a Cv = 0.32.

  3. Incidental necropsy finding of a quadricuspid aortic valve.

    PubMed

    van Rijswijk, Jan Willem; Willemink, Martin J; Kluin, Jolanda; Vink, Aryan

    2015-01-01

    Quadricuspid aortic valve is a rare congenital cardiac malformation often associated with abnormal valve function. In this article, we present a case of quadricuspid aortic valve only diagnosed at the time of post-mortem examination. PMID:25754175

  4. 49 CFR 192.747 - Valve maintenance: Distribution systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Valve maintenance: Distribution systems. 192.747 Section 192...747 Valve maintenance: Distribution systems. (a) Each valve, the...for the safe operation of a distribution system, must be checked and...

  5. 49 CFR 192.181 - Distribution line valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Pipeline Components § 192.181 Distribution line valves. (a) Each high-pressure distribution system must have valves spaced so as...the flow or pressure of gas in a distribution system must have a valve installed...

  6. 49 CFR 192.363 - Service lines: Valve requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Service lines: Valve requirements. 192.363 Section 192...Lines § 192.363 Service lines: Valve requirements. (a) Each service line must have a service-line valve that meets the applicable...

  7. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125 Shipping...Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray system must meet Part...

  8. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... false Inlets and discharge piping: Valves. 45.155 Section 45.155 Shipping...155 Inlets and discharge piping: Valves. (a) Except as provided in paragraphs...have— (1) An automatic nonreturn valve with a positive means for closing;...

  9. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Valve maintenance: Transmission lines. 192...STANDARDS Maintenance § 192.745 Valve maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  10. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125 Shipping...Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray system must meet Part...

  11. 49 CFR 192.747 - Valve maintenance: Distribution systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Valve maintenance: Distribution systems. 192...SAFETY STANDARDS Maintenance § 192.747 Valve maintenance: Distribution systems. (a) Each valve, the use of which may be necessary...

  12. 46 CFR 153.980 - Isolation of automatic closing valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Isolation of automatic closing valves. 153.980 Section 153.980...980 Isolation of automatic closing valves. The person in charge of cargo transfer may isolate automatic closing valves described in § 153.408(b)...

  13. 46 CFR 153.980 - Isolation of automatic closing valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Isolation of automatic closing valves. 153.980 Section 153.980...980 Isolation of automatic closing valves. The person in charge of cargo transfer may isolate automatic closing valves described in § 153.408(b)...

  14. 49 CFR 192.193 - Valve installation in plastic pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...3 2010-10-01 2010-10-01 false Valve installation in plastic pipe. 192.193 ...Design of Pipeline Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be...

  15. 46 CFR 153.980 - Isolation of automatic closing valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...false Isolation of automatic closing valves. 153.980 Section 153.980...980 Isolation of automatic closing valves. The person in charge of cargo transfer may isolate automatic closing valves described in § 153.408(b)...

  16. 46 CFR 153.980 - Isolation of automatic closing valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Isolation of automatic closing valves. 153.980 Section 153.980...980 Isolation of automatic closing valves. The person in charge of cargo transfer may isolate automatic closing valves described in § 153.408(b)...

  17. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Valve maintenance: Transmission lines. 192...STANDARDS Maintenance § 192.745 Valve maintenance: Transmission lines. (a) Each transmission line valve that might be required during any...

  18. 49 CFR 192.365 - Service lines: Location of valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... false Service lines: Location of valves. 192.365 Section 192.365 Transportation...192.365 Service lines: Location of valves. (a) Relation to regulator or meter. Each service-line valve must be installed upstream of the...

  19. 49 CFR 192.193 - Valve installation in plastic pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...3 2011-10-01 2011-10-01 false Valve installation in plastic pipe. 192.193 ...Design of Pipeline Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be...

  20. 49 CFR 192.363 - Service lines: Valve requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Service lines: Valve requirements. 192.363 Section 192...Lines § 192.363 Service lines: Valve requirements. (a) Each service line must have a service-line valve that meets the applicable...

  1. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Inlets and discharge piping: Valves. 45.155 Section 45.155 Shipping...155 Inlets and discharge piping: Valves. (a) Except as provided in paragraphs...have— (1) An automatic nonreturn valve with a positive means for closing;...

  2. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125 Shipping...Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray system must meet Part...

  3. 49 CFR 192.365 - Service lines: Location of valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... false Service lines: Location of valves. 192.365 Section 192.365 Transportation...192.365 Service lines: Location of valves. (a) Relation to regulator or meter. Each service-line valve must be installed upstream of the...

  4. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Inlets and discharge piping: Valves. 45.155 Section 45.155 Shipping...155 Inlets and discharge piping: Valves. (a) Except as provided in paragraphs...have— (1) An automatic nonreturn valve with a positive means for closing;...

  5. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Inlets and discharge piping: Valves. 45.155 Section 45.155 Shipping...155 Inlets and discharge piping: Valves. (a) Except as provided in paragraphs...have— (1) An automatic nonreturn valve with a positive means for closing;...

  6. 46 CFR 45.155 - Inlets and discharge piping: Valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... false Inlets and discharge piping: Valves. 45.155 Section 45.155 Shipping...155 Inlets and discharge piping: Valves. (a) Except as provided in paragraphs...have— (1) An automatic nonreturn valve with a positive means for closing;...

  7. 49 CFR 192.193 - Valve installation in plastic pipe.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...3 2012-10-01 2012-10-01 false Valve installation in plastic pipe. 192.193 ...Design of Pipeline Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be...

  8. 46 CFR 153.980 - Isolation of automatic closing valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...false Isolation of automatic closing valves. 153.980 Section 153.980...980 Isolation of automatic closing valves. The person in charge of cargo transfer may isolate automatic closing valves described in § 153.408(b)...

  9. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125 Shipping...Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray system must meet Part...

  10. 49 CFR 192.365 - Service lines: Location of valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... false Service lines: Location of valves. 192.365 Section 192.365 Transportation...192.365 Service lines: Location of valves. (a) Relation to regulator or meter. Each service-line valve must be installed upstream of the...

  11. 49 CFR 192.193 - Valve installation in plastic pipe.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...3 2014-10-01 2014-10-01 false Valve installation in plastic pipe. 192.193 ...Design of Pipeline Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be...

  12. 49 CFR 192.363 - Service lines: Valve requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Service lines: Valve requirements. 192.363 Section 192...Lines § 192.363 Service lines: Valve requirements. (a) Each service line must have a service-line valve that meets the applicable...

  13. 49 CFR 192.363 - Service lines: Valve requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Service lines: Valve requirements. 192.363 Section 192...Lines § 192.363 Service lines: Valve requirements. (a) Each service line must have a service-line valve that meets the applicable...

  14. 49 CFR 192.365 - Service lines: Location of valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Service lines: Location of valves. 192.365 Section 192.365 Transportation...192.365 Service lines: Location of valves. (a) Relation to regulator or meter. Each service-line valve must be installed upstream of the...

  15. 49 CFR 192.365 - Service lines: Location of valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... false Service lines: Location of valves. 192.365 Section 192.365 Transportation...192.365 Service lines: Location of valves. (a) Relation to regulator or meter. Each service-line valve must be installed upstream of the...

  16. 49 CFR 192.363 - Service lines: Valve requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Service lines: Valve requirements. 192.363 Section 192...Lines § 192.363 Service lines: Valve requirements. (a) Each service line must have a service-line valve that meets the applicable...

  17. 49 CFR 192.747 - Valve maintenance: Distribution systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 2011-10-01 false Valve maintenance: Distribution systems. 192...SAFETY STANDARDS Maintenance § 192.747 Valve maintenance: Distribution systems. (a) Each valve, the use of which may be necessary...

  18. 46 CFR 154.1125 - Pipes, fittings, and valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Pipes, fittings, and valves. 154.1125 Section 154.1125 Shipping...Firefighting § 154.1125 Pipes, fittings, and valves. (a) Each pipe, fitting, and valve for each water spray system must meet Part...

  19. Scopulariopsis brevicaulis infection of prosthetic valve resembling aspergilloma on histopathology.

    PubMed

    Jain, Deepali; Oberoi, Jaswinder Kaur; Shahi, Sudhir Kumar; Shivnani, Ganesh; Wattal, Chand

    2011-01-01

    Fungal prosthetic valve endocarditis is an infrequent but serious complication of valve replacement surgery. Approximately 75% of patients are affected with Candida species. Scopulariopsis species affecting prosthetic valve is rarely reported in the literature. PMID:21185746

  20. APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN ...

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

    APPROACH BRIDGE PORTION OF VALVE TOWER FOOT BRIDGE, AS SEEN FROM BELOW, SHOWING VALVE TOWER TO RIGHT. VIEW FACING NORTH - Schofield Barracks Military Reservation, Ku Tree Reservoir, Valve Tower Foot Bridge, Kalakoa Stream, East Range, Wahiawa, Honolulu County, HI

  1. 30 CFR 56.16006 - Protection of gas cylinder valves.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Protection of gas cylinder valves. 56.16006 Section...Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE...Protection of gas cylinder valves. Valves on...

  2. 46 CFR 154.519 - Piping relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Piping relief valves. 154.519 Section 154...CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED... § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo...

  3. 46 CFR 109.333 - Fire main cutoff valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Fire main cutoff valves. 109.333 Section 109... Operation and Stowage of Safety Equipment § 109.333 Fire main cutoff valves. The master or person...insure that each fire main cutoff valve is open and sealed to...

  4. 30 CFR 57.16006 - Protection of gas cylinder valves.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Protection of gas cylinder valves. 57.16006 Section...Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND...Protection of gas cylinder valves. Valves on...

  5. Hydraulic engine valve actuation system including independent feedback control

    DOEpatents

    Marriott, Craig D

    2013-06-04

    A hydraulic valve actuation assembly may include a housing, a piston, a supply control valve, a closing control valve, and an opening control valve. The housing may define a first fluid chamber, a second fluid chamber, and a third fluid chamber. The piston may be axially secured to an engine valve and located within the first, second and third fluid chambers. The supply control valve may control a hydraulic fluid supply to the piston. The closing control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the second fluid chamber to the supply control valve. The opening control valve may be located between the supply control valve and the second fluid chamber and may control fluid flow from the supply control valve to the second fluid chamber.

  6. Prevalence of mitral valve prolapse and congenital bicuspid aortic valves in black and white patients undergoing cardiac valve operations.

    PubMed

    Novaro, Gian M; Houghtaling, Penny L; Gillinov, A Marc; Blackstone, Eugene H; Asher, Craig R

    2013-03-15

    The risk factors for aortic and mitral valve diseases that require surgical repair such as congenital bicuspid aortic valve (BAV) and mitral valve prolapse include acquired clinical factors and genetic influences. Whether race affects the prevalence of certain valvular diseases has not been sufficiently investigated. Through the Cleveland Clinic's Cardiovascular Information Registry, we evaluated the data from 40,419 patients who had undergone aortic valve surgery, mitral valve surgery, and/or coronary artery bypass grafting from 1993 to 2007. Of these patients, 38,366 were white and 2,053 were black. The prospective evaluation of valvular disease was coded, identifying the etiology and morphology by echocardiographic, surgical, and pathologic inspection. At baseline, compared to white patients, the black patients were younger, more often women, had a greater body mass index, and a greater prevalence of hypertension, diabetes, tobacco use, and renal disease. The prevalence of congenital BAV and mitral valve prolapse was considerably lower in blacks than in whites (9% vs 25%, p <0.001, and 27% vs 52%, p <0.001, respectively), as was the presence of calcific aortic stenosis (14% vs 28%; p <0.001), pathologically determined aortic valve calcium (50% vs 67%; p <0.001), and mitral valve chordal rupture (13% vs 31%; p <0.001). In conclusion, in the present large surgical series, the valve etiologies and morphology differed among blacks and whites. Despite an adverse cardiovascular risk profile, blacks had a significantly lower prevalence of valvular calcium and degeneration than did the whites and a lower prevalence of congenital BAV and mitral valve prolapse. Our findings offer insight into the influence of race on the development of mitral valve disease and congenital BAV. PMID:23276473

  7. Project W-314 241-AN-B valve pit upgrade acceptance for beneficial use

    SciTech Connect

    HAMMERS, J.S.

    1999-07-21

    This report identifies the responsibilities and requirements, applicable to the 241-AN-B Valve Pit Upgrades portion of Project W-314, for Acceptance for Beneficial Use in accordance with HNF-IP-0842, Vol IV, Sec 3.12. At project turnover, the end user accepts the affected Structures, Systems, and Components (SSCs) for beneficial use. This checklist is used to help the end user ensure that all documentation, training, and testing requirements are met prior to turnover. This checklist specifically identifies those items related to the upgrading of the 241-AN-B valve pit. The upgrades include: the installation of jumper/valve manifolds with position sensors, replacement pit leak detection systems, construction of replacement cover blocks, and electrical upgrades to support the instrumentation upgrades.

  8. Project W-314 241-AN-A valve pit upgrade acceptance for beneficial use

    SciTech Connect

    HAMMERS, J.S.

    1999-07-21

    This report identifies the responsibilities and requirements, applicable to the 241-AN-A Valve Pit Upgrades portion of Project W-314, for Acceptance for Beneficial Use in accordance with HNF-IP-0842, Vol IV, Sec 3.12. At project turnover, the end user accepts the affected Structures, Systems, and Components (SSCs) for beneficial use. This checklist is used to help the end user ensure that all documentation, training, and testing requirements are met prior to turnover. This checklist specifically identifies those items related to the upgrading of the 241-AN-A valve pit. The upgrades include: the installation of jumper/valve manifolds with position sensors, replacement pit leak detection systems, construction of replacement cover blocks, and electrical upgrades to support the instrumentation upgrades.

  9. A randomized controlled trial in a training institution comparing a pediatric variable stiffness colonoscope, a pediatric colonoscope, and an adult colonoscope

    Microsoft Academic Search

    Douglas A. Shumaker; Atif Zaman; Ronald M. Katon

    2002-01-01

    Background: There are few comparative data on the efficacy of different colonoscopes. This study compared the efficacy of a new pediatric variable stiffness colonoscope with that of standard pediatric and adult colonoscopes in the performance of routine colonoscopy. Methods: Three hundred sixty-three consecutive patients were randomized to undergo colonoscopy with a pediatric variable stiffness (n = 122), pediatric (n =

  10. 40 CFR 61.243-1 - Alternative standards for valves in VHAP service-allowable percentage of valves leaking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Alternative standards for valves in VHAP service-allowable percentage of valves leaking. 61.243-1 Section 61.243-1...61.243-1 Alternative standards for valves in VHAP service—allowable percentage...

  11. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Arrangements for removal of valves from venting systems having multiple relief valves. 153.361 Section 153.361 Shipping... § 153.361 Arrangements for removal of valves from venting systems having multiple...

  12. 40 CFR 61.243-1 - Alternative standards for valves in VHAP service-allowable percentage of valves leaking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Alternative standards for valves in VHAP service-allowable percentage of valves leaking. 61.243-1 Section 61.243-1...61.243-1 Alternative standards for valves in VHAP service—allowable percentage...

  13. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Arrangements for removal of valves from venting systems having multiple relief valves. 153.361 Section 153.361 Shipping... § 153.361 Arrangements for removal of valves from venting systems having multiple...

  14. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Arrangements for removal of valves from venting systems having multiple relief valves. 153.361 Section 153.361 Shipping... § 153.361 Arrangements for removal of valves from venting systems having multiple...

  15. 40 CFR 61.243-1 - Alternative standards for valves in VHAP service-allowable percentage of valves leaking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Alternative standards for valves in VHAP service-allowable percentage of valves leaking. 61.243-1 Section 61.243-1...61.243-1 Alternative standards for valves in VHAP service—allowable percentage...

  16. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Arrangements for removal of valves from venting systems having multiple relief valves. 153.361 Section 153.361 Shipping... § 153.361 Arrangements for removal of valves from venting systems having multiple...

  17. 40 CFR 61.243-1 - Alternative standards for valves in VHAP service-allowable percentage of valves leaking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Alternative standards for valves in VHAP service-allowable percentage of valves leaking. 61.243-1 Section 61.243-1...61.243-1 Alternative standards for valves in VHAP service—allowable percentage...

  18. 40 CFR 61.243-1 - Alternative standards for valves in VHAP service-allowable percentage of valves leaking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Alternative standards for valves in VHAP service-allowable percentage of valves leaking. 61.243-1 Section 61.243-1...61.243-1 Alternative standards for valves in VHAP service—allowable percentage...

  19. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Arrangements for removal of valves from venting systems having multiple relief valves. 153.361 Section 153.361 Shipping... § 153.361 Arrangements for removal of valves from venting systems having multiple...

  20. Bladder Function Associated With Posterior Urethral Valves After Primary Valve Ablation or Proximal Urinary Diversion in Children and Adolescents

    Microsoft Academic Search

    M. Podestá; A. C. Ruarte; C. Gargiulo; R. Medel; R. Castera; M. Herrera

    2002-01-01

    PurposeWe retrospectively reviewed 2 series of patients with posterior urethral valves treated initially with valve ablation preceded by bilateral cutaneous ureterostomies or valve ablation alone to evaluate and compare bladder function behavior of each treatment group.