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1

Variable Orifice Ball Valve.  

National Technical Information Service (NTIS)

A variable orifice ball valve includes an external housing with a longitudinal fluid bore formed therethrough. A ball member is rotatably positioned within the external housing. The ball member can include first and second ball portions, with the longitud...

P. E. Moody

1996-01-01

2

Gasoline engine valve-train mechanism simulation  

Microsoft Academic Search

The paper describes the engine valve-train mechanism's dynamic analysis method, and introduces how to make dynamic simulation of it, and then makes the conclusions from the simulation results. In the process of simulation, first engine valve-train mechanism is modeled by CATIA software, and then models are imported into ADAMS software, so as to simulate the movement of engine valve-train mechanism.

Wang Xihui; Li Jing

2011-01-01

3

Valve Jump Prediction Using Dynamic Simulation on Direct Acting Valve Train  

Microsoft Academic Search

With regard to the direct acting valve train that has high stiffness in nature, it is generally believed that the valve spring surge is the sole and primary cause that induces valve jump. As Mitsubishi Motors Corporation (MMC) employs direct acting valve trains for its new model engines, clarifying the valve jump generating mechanism is essential for future improvement in

Akihiro FUJIMOTO; Hirofumi HIGASHI; Noritsugu OSAWA; Hideo NAKAI; Tokiichi MIZUKAMI

4

Heart rate variability in soccer players with mitral valve prolapse or benign arrhythmia  

Microsoft Academic Search

Numerous studies have reported increased cardiac vagal activity in well endurance-trained athletes. However, no clear data exist regarding the cardiac autonomic activity in athletes with common cardiovascular findings, such as mild mitral valve prolapse (MVP) and transient benign arrhythmias. Therefore, the purpose of this study was to investigate and compare the cardiac autonomic outflow by heart rate variability (HRV) analysis

N. Koutlianos; E. Kouidi; A. Deligiannis

2004-01-01

5

Turbo-generator control with variable valve actuation  

DOEpatents

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.

Vuk, Carl T. (Denver, IA)

2011-02-22

6

Study of fluid flow and combustion with variable valve timing.  

National Technical Information Service (NTIS)

The effects of variable valve timing (VVT) were examined by in-cylinder Laser Doppler Velocimetry flow measurements and heat-release calculations. A single-cylinder Volvo B5254 engine was used for all experiments and the valve timing was altered by phasin...

F. Soederberg

1998-01-01

7

Pressure variable orifice for hydraulic control valve  

NASA Technical Reports Server (NTRS)

Hydraulic valve absorbs impact energy generated in docking or joining of two large bodies by controlling energy release to avoid jarring shock. The area of exit porting presented to the hydraulic control fluid is directly proportional to the pressure acting on the fluid.

Ammerman, R. L.

1968-01-01

8

Engine having a variable valve actuation system  

DOEpatents

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

Hefler, Gregory W. (Chillicothe, IL)

2004-10-12

9

Engine having a variable valve actuation system  

DOEpatents

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

Hefler, Gregory W. (Chillicothe, IL)

2005-10-12

10

The lubrication of engine valve trains equipped with ceramicized followers  

Microsoft Academic Search

The valve train wear characteristics of motored 2.2l and 2.3l engines were examined using ceramic and conventional metal cam followers. Under regular wear conditions with fully formulated motor oils, minimal wear was observed on the metal cam lobes running with either the ceramicized or metal followers. Running under chemically accelerated wear conditions with low quality oil, however, cam lobe wear

A. G. Blahey; J. J. Habeeb

1990-01-01

11

Advanced Technology Training System on Motor-Operated Valves  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

12

Transcatheter heart valve with variable geometric configuration: in vitro evaluation.  

PubMed

Clinically, the current transcatheter aortic valve (TAV) technology has shown a propensity for paravalvular leakage; studies have correlated this flaw to increased calcification at the implantation site and with nonideal geometry of the stented valve. The present study evaluated the hydrodynamics of different geometric configurations, in particular the intravalvular considerations. Three TAV devices were made to create a representative, size 26 mm TAV. Hydrodynamics were assessed using a pulse duplicator. The geometries tested were composed of the nominal, elliptical, triangular, and undersized shapes; along with half-constriction, a conformation in which only a portion of the stent was constrained. The TAVs were assessed for transvalvular pressure gradient (TVG), effective orifice area (EOA), and regurgitant fraction. The nominal-sized shape posed a larger TVG (6.2 ± 0.3 mm Hg) than other configurations (P < 0.001) except the undersized valves. EOA of the nominal sized TAV (1.7 ± 0.1 cm(2) ) was smaller than that of the triangular and half-elliptical versions (P < 0.001). The half- and full-undersized geometries had EOAs smaller than the nominal type (P < 0.001). Nominal shape had smaller regurgitation (6.7 ± 1.4%) than all configurations (P < 0.001) except for the half-undersized (4.0 ± 0.7, P < 0.001) with no statistically significant difference from the full-undersized (6.8 ± 1.3, P = 0.724). The testing of variable geometries showed significant differences from the nominal geometry with respect to TVG, EOA, and regurgitant fraction. In particular, many of these nonideal configurations demonstrated an increased intravalvular regurgitation. PMID:21951229

Young, Ernest; Chen, Ji-Feng; Dong, Owen; Gao, Shengqiang; Massiello, Alex; Fukamachi, Kiyotaka

2011-12-01

13

Fault diagnosis for diesel valve trains based on time frequency images  

NASA Astrophysics Data System (ADS)

In this paper, the Wigner-Ville distributions (WVD) of vibration acceleration signals which were acquired from the cylinder head in eight different states of valve train were calculated and displayed in grey images; and the probabilistic neural networks (PNN) were directly used to classify the time-frequency images after the images were normalized. By this way, the fault diagnosis of valve train was transferred to the classification of time-frequency images. As there is no need to extract further fault features (such as eigenvalues or symptom parameters) from time-frequency distributions before classification, the fault diagnosis process is highly simplified. The experimental results show that the faults of diesel valve trains can be classified accurately by the proposed methods.

Wang, Chengdong; Zhang, Youyun; Zhong, Zhenyuan

2008-11-01

14

Non-reversible multiple-refrigeration-cycle solar apparatus including a variable directing valve mechanism  

SciTech Connect

A non-reversible multiple-refrigeration-cycle solar apparatus, including a variable directing valve mechanism for conditioning a medium, defrosting the apparatus, and absorbing, storing and using solar energy.

Cramer Sr., C. V.

1985-11-19

15

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

Microsoft Academic Search

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

Ryan R. Chladny; Charles R. Koch

2008-01-01

16

Effect analysis of design variables on the disc in a double-eccentric butterfly valve.  

PubMed

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

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

2014-01-01

17

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

PubMed Central

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

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

2014-01-01

18

Valve  

DOEpatents

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.

Cho, Nakwon (Knoxville, TN)

1980-01-01

19

Emulational simulation of valve train based on rigid-flexible coupling model  

Microsoft Academic Search

By adopting the idea of firstly building the entity model, then introducing it into ADAMS to build a multiple-rigid-body model, and at last replacing part of the components with the finite element model, the rigid-flexible coupling dynamic analysis model for the valve train of a certain type of diesel engine is set up. Meanwhile, the dynamic simulation analysis on the

Dongjie Zhao; Hongliang Guo; Zhenhua Qi

2011-01-01

20

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

SciTech Connect

An analytical study was made of advantages provided by electronically controlled hydraulically activated valves when applied to a low heat rejection engine with and without exhaust heat recovery devices. The valves, which could be designed to operate with variable timings and variable rates of opening and closing, would allow the use of certain sophisticated valve strategies not possible with conventional systems. Three individual investigations were carried out. The first concerned the optimization of the timing and rate of valve opening at several speeds and loads, to obtain maximum volumetric efficiency and lowest BSFC. A second investigated early intake valve closing (IVC before BDC), coupled with increased boost, a concept that had been suggested previously in the literature. The present results showed much lower benefits than those predicted by the earlier study. The final study addressed the use of an organic Rankine cycle bottomer (ORCB) to extract energy from the exhaust stream and directing the ORCB output power to the engine air compressor shaft rather than to the engine output shaft. At rated engine conditions, when not employing a power turbine, this concept was found to produce higher BSFC compared to the more standard configuration where the ORBC was directly coupled to the engine shaft. When a power turbine was used between the engine and the ORCB, nearly the same BSFC was achieved with the two configurations.

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

1987-10-01

21

Two-parameter power-variable-training STAP  

Microsoft Academic Search

Airborne ground moving target indicator (GMTI) radars must employ a method of radar clutter mitigation to separate moving objects from stationary ground clutter. Two-parameter, power variable training STAP effectively combines two distinct STAP methods to improve clutter suppression, target detection, and angle estimation. Power variable training STAP utilizes a clutter covariance scaling factor to prevent clutter overing and undering that

Gerald Benitz; Jacob D. Griesbach; Charles Rader

2004-01-01

22

Manipulating the Number and Type of Adaptive Variables in Training.  

National Technical Information Service (NTIS)

To investigate the effectiveness of various types and numbers of adaptive variables, 48 subjects performed a two-dimensional pursuit tracking task for five three-minute training sessions. In the factorial design resulting in eight experimental conditions,...

D. Gopher B. H. Williges R. C. Williges D. L. Damos

1974-01-01

23

Training models of anatomic shape variability.  

PubMed

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

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

2008-08-01

24

Safety and efficiency assessment of training Canadian cardiac surgery residents to perform aortic valve surgery  

PubMed Central

Background Research has demonstrated equivalent patient safety outcomes for various cardiac procedures when the primary surgeon was a supervised trainee. However, cardiac surgery cases have become more complex, and the Canadian cardiac surgery education model has undergone some changes. We sought to compare patient safety and efficiency of aortic valve replacement (AVR) between Canadian patients treated by senior cardiac trainees and those treated by certified cardiac surgeons. Methods We completed a single-centre, case-matched, prospectively collected and retrospectively analyzed study of AVR. Patients were matched between trainees and consultants for age, sex, New York Heart Association and Canadian Cardiovascular Society status, urgency of operation and diabetes status. Results We analyzed 1102 procedures: 624 isolated AVRs and 478 AVRs with coronary artery bypass graft (CABG). For isolated AVR, there was no significant difference in 30-d mortality (p = 0.13) or in major adverse events (p = 0.38) between the groups. In the AVR+CABG group, there was no significant difference in 30-day mortality (p = 0.10) or in the rates of major adverse events (p = 0.37) between the groups. Secondary outcomes (hospital and intensive care unit lengths of stay, valve size and type) did not differ significantly between the groups for isolated AVR or AVR+CABG. Conclusion Despite a higher-risk patient population and changes in the cardiac surgery training model, it appears that outcomes are not negatively affected when a senior trainee acts as the primary surgeon in cases of AVR.

Chen, Kuan-chin Jean; Adams, Corey; Stitt, Larry W.; Guo, L. Ray

2013-01-01

25

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

PubMed

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

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

2013-09-01

26

Individualised training to address variability of radiologists' performance  

NASA Astrophysics Data System (ADS)

Computer-based tools are increasingly used for training and the continuing professional development of radiologists. We propose an adaptive training system to support individualised learning in mammography, based on a set of real cases, which are annotated with educational content by experienced breast radiologists. The system has knowledge of the strengths and weakness of each radiologist's performance: each radiologist is assessed to compute a profile showing how they perform on different sets of cases, classified by type of abnormality, breast density, and perceptual difficulty. We also assess variability in cognitive aspects of image perception, classifying errors made by radiologists as errors of search, recognition or decision. This is a novel element in our approach. The profile is used to select cases to present to the radiologist. The intelligent and flexible presentation of these cases distinguishes our system from existing training tools. The training cases are organised and indexed by an ontology we have developed for breast radiologist training, which is consistent with the radiologists' profile. Hence, the training system is able to select appropriate cases to compose an individualised training path, addressing the variability of the radiologists' performance. A substantial part of the system, the ontology has been evaluated on a large number of cases, and the training system is under implementation for further evaluation.

Sun, Shanghua; Taylor, Paul; Wilkinson, Louise; Khoo, Lisanne

2008-04-01

27

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

28

Torque Control for Automotive Engines with Variable Valves via Air and Burned Gas Flow-Based Design  

NASA Astrophysics Data System (ADS)

This paper proposes a predictive control method for automotive engines with variable valves. The control purpose is to track not only the torque reference but also the pressure reference of the surge tank in consideration for the constraint of internal exhaust gas recirculation ratio. The control inputs are the throttle angle and the intake valve lift, however, the proposed control method is based on a flow model where the mass flows through the throttle and the intake valves are regarded as the virtual control inputs. The controller designed for the SICE benchmark engine is validated by numerical simulations.

Jimbo, Tomohiko; Hayakawa, Yoshikazu

29

Variable stiffness and damping suspension system for train  

NASA Astrophysics Data System (ADS)

As the vibration of high speed train becomes fierce when the train runs at high speed, it is crucial to develop a novel suspension system to negotiate train's vibration. This paper presents a novel suspension based on Magnetorheological fluid (MRF) damper and MRF based smart air spring. The MRF damper is used to generate variable damping while the smart air spring is used to generate field-dependent stiffness. In this paper, the two kind smart devices, MRF dampers and smart air spring, are developed firstly. Then the dynamic performances of these two devices are tested by MTS. Based on the testing results, the two devices are equipped to a high speed train which is built in ADAMS. The skyhook control algorithm is employed to control the novel suspension. In order to compare the vibration suppression capability of the novel suspension with other kind suspensions, three other different suspension systems are also considered and simulated in this paper. The other three kind suspensions are variable damping with fixed stiffness suspension, variable stiffness with fixed damping suspension and passive suspension. The simulation results indicate that the variable damping and stiffness suspension suppresses the vibration of high speed train better than the other three suspension systems.

Sun, Shuaishuai; Deng, Huaxia; Li, Weihua

2014-03-01

30

Statistical analysis of nuclear power plant valve failure-rate variability: some preliminary results  

Microsoft Academic Search

Valve failure data from the In-Plant Reliability Data System (IPRDS) are statistically analyzed using the Failure Rate Analysis Code (FRAC). Data from five failure modes, four of which are time related and the other demand related, are analyzed to determine which of the factors - operating system, valve size, valve type, operating type, and operating mode - most affect valve

R. J. Beckman; H. F. Martz

1985-01-01

31

Depression, heart rate variability, and exercise training in dialysis patients  

Microsoft Academic Search

Background Functional limitations, altered cardiac autonomic activity, and psychological distress are known disorders in chronic hemodialysis (HD) patients, relating to increased morbidity and mortality. The aim of this study was to examine the influence of an exercise training program on emotional parameters and heart rate variability (HRV) indices, as well as to determine whether emotional stress contributes to autonomic dysfunction

Evangelia Kouidi; Vassilis Karagiannis; Dimitrios Grekas; Apostolos Iakovides; George Kaprinis; Achilleas Tourkantonis; Asterios Deligiannis

2010-01-01

32

Effects of training period on haemorheological variables in regularly trained footballers  

PubMed Central

Objective: To investigate the effects of one football training period on haemorheological variables in regularly trained footballers. Method: Ten subjects were randomly selected from the reserve team of a football club in the Turkish Premier League. During the last week of the football season, one day before a standard training session and two days after the previous league match, venous blood samples were taken (pre-exercise). After 90 minutes of standard training, further blood samples were taken (post-exercise). Blood lactate, blood viscosity, plasma fibrinogen, blood clotting time, acid-base variables, and plasma Na+, K+, and Ca2+ were determined. Results: Haemoglobin, packed cell volume, and mean corpuscular volume were all significantly decreased, whereas white blood cells and platelets were both increased after training. Blood viscosity decreased but the reduction was not significant. Blood lactate, plasma glucose, and Na+ content were significantly increased, but standard bicarbonate, actual bicarbonate, and Ca2+ were significantly decreased. Blood clotting time had shortened significantly after training. Blood viscosity was inversely correlated with plasma glucose concentration (r = –0.48 and p = 0.032). Conclusions: The results show that blood viscosity tends to decrease as the result of this type of training. This is due to a reduction in packed cell volume and mean corpuscular volume. The increased blood lactate does not have an adverse effect on the blood viscosity of these subjects because protective mechanisms develop with regular training throughout the season.

Karakoc, Y; Duzova, H; Polat, A; Emre, M; Arabaci, I

2005-01-01

33

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

Microsoft Academic Search

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

Paul M. Lehrer; Evgeny Vaschillo; Bronya Vaschillo

2000-01-01

34

Heart rate variability in children with aortic valve stenosis - a pilot study  

PubMed Central

Introduction The aim of our prospective study was to evaluate heart rate variability (HRV) in children with aortic valve stenosis (AS) and its relationship with left ventricular mass and peak transaortic valve pressure gradient (PG). Material and methods Sixty children with AS divided into 3 groups according to their PG and 60 healthy controls were studied. Holter ECG monitoring with time domain HRV analysis was performed. Left ventricular mass was calculated by echocardiography. Results Mean values of all HRV parameters were statistically significantly lower (p < 0.001) in children with AS than in controls (respectively: SDNN 127.8 ±28.2 ms; 162.6 ±38.0 ms, SDNN day 99.7 ±26.6 ms; 134.1 ±36.1 ms, SDNN night 99.9 ±32.8 ms; 123.4 ±45.7 ms, SDANN 112.2 ±27.7 ms; 142.4 ±34.6, SDNNi 62.2 ±16.2 ms; 75.9 ±21.6, RMSSD 39.6 ±12.1 ms; 50.3 ±16.7 ms, rMSSD day 33.6 ±10.9 ms; 43.1 ±14.7 ms, rMSSD night 49.8 ±18.1 ms; 64.4 ±24.9 ms, pNN50 16.4 ±9.5%; 23.5 ±11.7%, pNN50 day 12.0 ±8.5%; 18.4 ±10.7%, pNN50 night; 26.5 ±14.8%; 36.4 ±17.4%. No significant differences between the mean values of HRV parameters in children with different PG and with and without myocardial hypertrophy were found. In children with AS and ventricular arrhythmia SDNN day was significantly lower (p < 0.05) compared to patients without arrhythmia (94.9 ±22.1 ms vs. 109.3 ±22.5 ms). Conclusions In children with AS the balance of the autonomic nervous systemic disturbed which manifests in an increase in sympathetic and decrease in parasympathetic activity. Transaortic valve pressure gradient and myocardial hypertrophy do not influence the HRV. The SDNN reduction during the day period may indicate the risk of ventricular arrhythmia in children with AS.

Piorecka-Makula, Anna; Bobkowski, Waldemar

2013-01-01

35

Endurance training guided individually by daily heart rate variability measurements.  

PubMed

Purpose of this study was to test utility of heart rate variability (HRV) in daily endurance exercise prescriptions. Twenty-six healthy, moderately fit males were randomized into predefined training group (TRA, n = 8), HRV-guided training group (HRV, n = 9), and control group (n = 9). Four-week training period consisted of running sessions lasting 40 min each at either low- or high-intensity level. TRA group trained on 6 days a week, with two sessions at low and four at high intensity. Individual training program for HRV group was based on individual changes in high-frequency R-R interval oscillations measured every morning. Increase or no change in HRV resulted in high-intensity training on that day. If there was significant decrease in HRV (below reference value [10-day mean-SD] or decreasing trend for 2 days), low-intensity training or rest was prescribed. Peak oxygen consumption (VO(2peak)) and maximal running velocity (Load(max)) were measured in maximal treadmill test before and after the training. In TRA group, Load(max) increased from 15.1 +/- 1.3 to 15.7 +/- 1.2 km h(-1) (P = 0.004), whereas VO(2peak) did not change significantly (54 +/- 4 pre and 55 +/- 3 ml kg(-1) min(-1) post, P = 0.224). In HRV group, significant increases were observed in both Load(max) (from 15.5 +/- 1.0 to 16.4 +/- 1.0 km h(-1), P < 0.001) and VO(2peak) (from 56 +/- 4 to 60 +/- 5 ml kg(-1) min(-1), P = 0.002). The change in Load(max) was significantly greater in HRV group compared to TRA group (0.5 +/- 0.4 vs. 0.9 +/- 0.2 km h(-1), P = 0.048, adjusted for baseline values). No significant differences were observed in the changes of VO(2peak) between the groups. We concluded that cardiorespiratory fitness can be improved effectively by using HRV for daily training prescription. PMID:17849143

Kiviniemi, Antti M; Hautala, Arto J; Kinnunen, Hannu; Tulppo, Mikko P

2007-12-01

36

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

DOEpatents

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.

Wiles, Matthew A.; Marriot, Craig D

2013-07-02

37

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

PubMed

Holliss, BA, Burden, RJ, Jones, AM, and Pedlar, CR. Eight weeks of intermittent hypoxic training improves submaximal physiological variables in highly trained runners. J Strength Cond Res 28(8): 2195-2203, 2014-It is unclear whether intermittent hypoxic training (IHT) results in improvements in physiological variables associated with endurance running. Twelve highly trained runners (V[Combining Dot Above]O2peak 70.0 ± 3.5 ml·kg·min) 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; p = 0.001) than after CONT ( -1 ± 5 b·min; 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·min; p = 0.001) and increasing in the CONT group in normoxia (+1.1 ± 2.1 ml·kg·min; p = 0.012). There were no V[Combining Dot Above]O2peak 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

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

2014-08-01

38

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

PubMed

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

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

1999-10-15

39

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

PubMed

Overload principle of training states that training load (TL) must be sufficient to threaten the homeostasis of cells, tissues, organs and/or body. However, there is no "golden standard" for TL measurement. The aim of the present study was to investigate if post-exercise heart rate variability (HRV) could be used to evaluate TL of interval running exercises with different intensities and durations. Thirteen endurance-trained men (35 ± 5 years) performed MO(250) [moderate intensity, 2 × 6 × 250 m/rec 30 s/5 min at 85% of the maximal velocity of the graded maximal test (V (max))], MO(500) (2 × 3 × 500 m/rec 1 min/5 min at 85% V (max)) and HI(250) (high intensity, 2 × 6 × 250 m/rec 30 s/5 min at 105% V (max)) interval exercises on a treadmill. HRV was analyzed during rest, exercise and immediate 15 min recovery. Fast recovery of LFP (P < 0.001), HFP (P < 0.01) and TP (P < 0.01) occurred during the first two recovery minutes after each exercise. Strong negative correlations (P < 0.01) were found between post-exercise HRV and perceived exertion as well as excess post-exercise oxygen consumption. Post-exercise HRV differentiated interval exercises of equal work, but varying intensity or distance of running bout. The results of the present study suggest that immediate post-exercise HRV may offer objective information on TL of interval exercises with different bout durations and intensities. PMID:21678140

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

2012-03-01

40

Resistance Training Increases the Variability of Strength Test Scores.  

National Technical Information Service (NTIS)

Informal observations made while conducting a meta-analysis of resistance training programs suggested that the between-person variation in strength test scores is greater after training than before. This study treated the informal observation as a hypothe...

A. C. Barnard J. R. Vickers L. K. Hervig

2009-01-01

41

Training of fuzzy inference systems by combining variable structure systems technique and Levenberg-Marquardt algorithm  

Microsoft Academic Search

This paper presents a novel training algorithm for fuzzy inference systems. The algorithm combines the Levenberg-Marquardt algorithm with variable structure systems approach. The combination is performed by expressing the parameter update rule in continuous time and application of sliding control method to the gradient based training procedure. In this paper, a fuzzy inference mechanism that can be trained such that

M. Onder Efe; Okyay Kaynak; Bogdan M. Wilamowski

1999-01-01

42

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

Microsoft Academic Search

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,

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

2009-01-01

43

Interference between concurrent resistance and endurance exercise: molecular bases and the role of individual training variables.  

PubMed

Concurrent training is defined as simultaneously incorporating both resistance and endurance exercise within a periodized training regime. Despite the potential additive benefits of combining these divergent exercise modes with regards to disease prevention and athletic performance, current evidence suggests that this approach may attenuate gains in muscle mass, strength, and power compared with undertaking resistance training alone. This has been variously described as the interference effect or concurrent training effect. In recent years, understanding of the molecular mechanisms mediating training adaptation in skeletal muscle has emerged and provided potential mechanistic insight into the concurrent training effect. Although it appears that various molecular signaling responses induced in skeletal muscle by endurance exercise can inhibit pathways regulating protein synthesis and stimulate protein breakdown, human studies to date have not observed such molecular 'interference' following acute concurrent exercise that might explain compromised muscle hypertrophy following concurrent training. However, given the multitude of potential concurrent training variables and the limitations of existing evidence, the potential roles of individual training variables in acute and chronic interference are not fully elucidated. The present review explores current evidence for the molecular basis of the specificity of training adaptation and the concurrent interference phenomenon. Additionally, insights provided by molecular and performance-based concurrent training studies regarding the role of individual training variables (i.e., within-session exercise order, between-mode recovery, endurance training volume, intensity, and modality) in the concurrent interference effect are discussed, along with the limitations of our current understanding of this complex paradigm. PMID:24728927

Fyfe, Jackson J; Bishop, David J; Stepto, Nigel K

2014-06-01

44

Emergent Literacy Skills and Training Time Uniquely Predict Variability in Responses to Phonemic Awareness Training in Disadvantaged Kindergartners.  

ERIC Educational Resources Information Center

Investigated factors that predicted variability in responses to analytic and synthetic phonemic awareness training with kindergartners living in poverty. Found that spelling skills were the most consistent predictor of variability in phonemic awareness in response to instruction. Amount of exposure children had to the intervention contributed to…

Hecht, Steven A.; Close, Linda

2002-01-01

45

Neuromuscular adaptations to constant vs. variable resistance training in older men.  

PubMed

This study examined the effects of constant or variable external resistance training on neuromuscular adaptations in the lower limbs of older men. 37 subjects (age 65±4?year) were quasi-randomly assigned to the constant or variable training group, or a non-training control group. Training consisted of a 20-week medium-intensity, high volume resistance training program. Maximum bilateral concentric and isometric force production of the leg extensors as well as repetitions-to-failure test were performed pre-, mid- and post-training. Vastus lateralis muscle cross-sectional area was assessed by ultrasound and lean leg mass was assessed by dual-energy x-ray absorptiometry. Both training groups significantly increased force production of the leg extensors (variable: 26?kg, 95% CI=12-39, P<0.01; constant: 31?kg, 95% CI=19-43, P<0.01) and VL cross-sectional area (variable: 1.5?cm2, 95% CI=0.03-3.1, P=0.046; constant: 3?cm2, 95% CI=1.2-4.8, P=0.002). However, only the variable training group significantly improved repetitions to failure performance (704?kg, 95% CI=45-1?364, P=0.035). Only the variable resistance training group improved fatigue-resistance properties, which may be an important adaptation to maintain exercise and functional capacity in older individuals. PMID:23825004

Walker, S; Peltonen, H; Sautel, J; Scaramella, C; Kraemer, W J; Avela, J; Häkkinen, K

2014-01-01

46

Analysis of heart rate variability after a ranger training course.  

PubMed

We studied the effects of prolonged physical activities on resting heart rate variability (HRV) during a training session attended by 23 cadets of the French military academy. This course lasts 1 month and is concluded by a 5-day field exercise simulation with physical and psychological stress. Data collection took place before (B) and immediately at the end (E) of the course. It included HRV recordings during a stand test (5 minutes lying down and 5 minutes standing), with a Polar R-R monitor, followed by blood sampling to assay plasma testosterone. The results (B and E) showed that the testosterone level fell by approximately 28.6 +/- 7%, indicating a high level of fatigue. During the stand test, the total power (TP) of the HRV spectrum increased in a supine position. The TP of B was 5,515.7 ms2 (SE, 718.4) and of E was 13018.9 ms2 (SE, 2,539.2; p < 0.001). High-frequency (HF) normalized values increased and low-frequency (LF) normalized values fell, regardless of position (HF normalized values and LF normalized values: supine, p < 0.01, p < 0.05; standing, p < 0.05, p < 0.01, respectively). LF:HF ratio fell 66.2 (SE, 12.9%; p < 0.01) in a lying position. During the time-domain analysis of HRV, differences between adjacent normal R-R intervals more than 50 milliseconds, expressed as a percentage, and differences between the coupling intervals of adjacent normal RR intervals increased in the lying position (p < 0.001). These results as a whole suggest that parasympathetic nervous system activity increases with fatigue. PMID:15379067

Jouanin, Jean-Claude; Dussault, Caroline; Pérès, Michel; Satabin, Pascale; Piérard, Christophe; Guézennec, Charles Yannick

2004-08-01

47

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

SciTech Connect

A hydraulic damping unit is described for controlling the spring action of vehicle suspension springs comprising a cylinder tube having a hydraulic fluid therein, a valved piston having a generally cylindrical body mounted for linear stroking movement in the cylinder tube and hydraulically separating the cylinder tube into first and second chambers, valve means within the body of the piston for controlling the flow of hydraulic fluid between the chambers through the piston, a piston rod connected directly to the body of the piston and extending to the exterior of the damping unit, a rotatable actuator operatively mounted in the piston rod. The valve means consists of an orifice plate fixed within the body of the piston having a plurality of hydraulic fluid flow controlling orifices therethrough, first and second deflectable spring disk means mounted on opposite sides of the orifice plate operatively associated with the orifices providing primary control of the damping force of the unit, fastener means extending through the orifice plate and the first and second disk means within the body of the piston, separate and varying size fluid flow passages extended through the fastener means in parallel with the orifices. The fastener means a head portion within the body of the piston, a selector plate rotatably mounted on the head portion and having a selector opening therein selectively registrable with any of the passages, means operatively connecting the selector plate to the actuator for rotation thereby so that any of the fluid flow passages can be selected for varying the damping action of the unit.

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

1987-08-11

48

Perceptions of Training-Related Factors and Personal Variables as Predictors of Transfer Implementation Intentions  

Microsoft Academic Search

A number of factors influence the outcomes of computer skills training and the likelihood of successful transfer. The first empirical test of a conceptual model of training transfer sought to explain how trainees' perceptions of various in-training transfer-enhancing activities such as overlearning, fidelity, stimulus variability, principles-meaningfulness, self-management activities, relapse prevention, and goal setting would predict the self-efficacy and implementation intentions

M. Anthony Machin; Gerard J. Fogarty

2003-01-01

49

Quantitative Analysis of the Effect of Resistance Training on Strength Test Score Variability.  

National Technical Information Service (NTIS)

This report extended an initial qualitative demonstration that test score variability increases during resistance training. Quantitative methods were applied to individual strength test data from 46 published studies. Analyses were limited to the four str...

A. C. Barnard J. R. Vickers L. K. Hervig

2009-01-01

50

Response Variability and Timing Precision of Neuronal Spike Trains In Vivo  

Microsoft Academic Search

yoshi Ozaki, and Ehud Kaplan. Response variability and timing matically. This behavior was found in every cell examined precision of neuronal spike trains in vivo. J. Neurophysiol. 77: in our study. A simple theoretical model for neuronal fir- 2836 - 2841, 1977. We report that neuronal spike trains can exhibit ing — the leaky or ''forgetful'' integrator ( Knight 1972

DANIEL S. REICH; JONATHAN D. VICTOR; BRUCE W. KNIGHT; TSUYOSHI OZAKI; EHUD K APLAN

51

Training Effects and Generalization of the Ability to Control Variables in High School Biology Students  

ERIC Educational Resources Information Center

Three Piagetian tests of formal reasoning were administered to 65 high school biology students after half of this group had been exposed to a training session involving the control of variables. Among the results of this study was that the concrete operational students benefited more from the training session than did the formal operational…

Lawson, Anton E.; And Others

1975-01-01

52

Central hemodynamic and heart rate variability parameters in athletes during different training programs  

Microsoft Academic Search

Central hemodynamic and heart rate variability (HRV) parameters were assessed in highly qualified athletes differing in the\\u000a types of their training programs at relative rest. During endurance (the endurance group, n = 27) and strength (the strength group, n = 17) trainings, the total peripheral resistance (TPR) was decreased by 15% (p = 0.003) in the endurance group and by

A. Yu. Mal’tsev; A. A. Mel’nikov; A. D. Vikulov; K. S. Gromova

2010-01-01

53

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

Microsoft Academic Search

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

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

54

Plant Maintenance/Training Manual (RADL Item 2-37): Section 4. Valves, Book 1 of 2. 10-MWe Solar-Thermal Central-Receiver Pilot Plant.  

National Technical Information Service (NTIS)

The valves documented include the modulating control and its related solenoid valves, and air operated stop and its related solenoid valves. The valves are listed, and many are individually described, including parts lists and specifications. (ERA citatio...

1981-01-01

55

Increasing Response Variability of Mand Frames with Script Training and Extinction  

ERIC Educational Resources Information Center

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…

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

2011-01-01

56

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

Microsoft Academic Search

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

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

1999-01-01

57

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

58

Safety valve  

DOEpatents

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.

Bergman, Ulf C. (Malmoe, SE)

1984-01-01

59

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

PubMed

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

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

2014-01-01

60

Exercise Training in Athletes with Bicuspid Aortic Valve Does Not Result in Increased Dimensions and Impaired Performance of the Left Ventricle  

PubMed Central

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

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

2014-01-01

61

Differences in Acceleration Training and Exercise Training on Resting Cardiovascular Variables  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

62

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

Microsoft Academic Search

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

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

1988-01-01

63

Overall increase in heart rate variability after the Square-Wave Endurance Exercise Test training  

Microsoft Academic Search

Objectives. – We studied the influence of the “Square-Wave Endurance Exercise Test” (SWEET) training program on heart rate (HR) variability during supine rest, 60° upright position and submaximal constant exercise.Methods. – Beat-by-beat HR was recorded during 10 min in the three conditions in 14 healthy women. Before and after 6 weeks of training (45 min, three times a week; n = 7) or

L. Mourot; N. Tordi; S. Perrey; M. Bouhaddi; J.-D. Rouillon; J. Regnard

2005-01-01

64

Association between heart rate variability and training response in sedentary middle-aged men  

Microsoft Academic Search

The effect of exercise training on heart rate variability (HRV) and improvements in peak oxygen consumption (\\u000a$$\\\\dot V{\\\\text{O}}_{\\\\text{2}} $$\\u000a\\u000apeak) was examined in sedentary middle-aged men. The HRV and absolute and relative\\u000a$$\\\\dot V{\\\\text{O}}_{\\\\text{2}} $$\\u000a\\u000apeak of training (n = 19) and control (n = 15) subjects were assessed before and after a 24-session moderate intensity exercise training programme.

Stephen H. Boutcher; Phyllis Stein

1995-01-01

65

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

NASA Astrophysics Data System (ADS)

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

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

2007-02-01

66

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)

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.

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

1992-01-01

67

Low friction servo valve  

NASA Technical Reports Server (NTRS)

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.

Dustin, M. O.

1968-01-01

68

Engine air intake valve  

Microsoft Academic Search

This paper discusses, in combination with an internal combustion engine, a system for regulating engine speed by regulating the air flow across a throttle valve in an air intake passage. It comprises an engine air intake valve and means of sensing an operating variable representative of engine speed and sending an electrical signal representative of the engine speed to the

1990-01-01

69

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

PubMed

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

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

2013-01-01

70

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

PubMed Central

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.

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

2013-01-01

71

10 MWe Solar Thermal Central Receiver Pilot Plant: Solar Facilities Design Integration. Plant Maintenance/Training Manual (RADL Item 2-37). Section 4. Valves, Book 2 of 3.  

National Technical Information Service (NTIS)

The valves documented include modulating control and related solenoid valves, air operated stop and related solenoid valves, motor operated valves, safety relief valves, and other solenoid valves. The valves are individually described, including parts lis...

1982-01-01

72

Cultural Background Variables in Dance Talent Development: Findings from the UK Centres for Advanced Training  

ERIC Educational Resources Information Center

This study is a qualitative enquiry into cultural background variables--social support, values, race/ethnicity and economic means--in the process of dance talent development. Seven urban dance students in pre-vocational training, aged 15-19, participated in semi-structured interviews. Interviews were inductively analysed using QSR International…

Sanchez, Erin N.; Aujla, Imogen J.; Nordin-Bates, Sanna

2013-01-01

73

HEART RATE VARIABILITY DURING RECOVERY IN TWO GROUPS WITH DIFFERENT TRAINING LEVEL  

Microsoft Academic Search

Heart Rate Variability (HRV) study, beside having a clini- cal interest, it has also worried researchers in exercise re- sponse and training adaptation. Although heart rate recov- ery (HRR) has been used as a cardiovascular index in mul- tiple tests, there is little information about the physiological mechanisms that explain the process of heart recovery af- ter exercise (1). Objective.

Lorenzo Irma; Calderón Francisco Javier; Benito Pedro

74

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

Microsoft Academic Search

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,

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

2000-01-01

75

Variable speed wind turbine based on multiple generators drive-train configuration  

Microsoft Academic Search

A variable speed wind turbine is presented in this paper, where multiple permanent magnet synchronous generators (MPMSGs) drive-train configuration is employed in the wind turbine. A cascaded multilevel converter interface based on the MPMSGs is developed to synthesize a desired high ac sinusoidal output voltage, which could be directly connected to the grids. What is more, such arrangement has been

Fujin Deng; Zhe Chen

2010-01-01

76

Heart rate variability reflects training load and psychophysiological status in young elite gymnasts.  

PubMed

In gymnastics, monitoring of the training load and assessment of the psychophysiological status of elite athletes is important for training planning and to avoid overtraining, consequently reducing the risk of injures. The aim of this study was to examine whether heart rate variability (HRV) is a valuable tool to determine training load and psychophysiological status in young elite gymnasts. Six young male elite gymnasts took part in a 10-week observational study. During this period, beat-to-beat heart rate intervals were measured every training day in weeks 1, 3, 5, 7, and 9. Balance, agility, upper limb maximal strength, lower limb explosive, and elastic power were monitored during weeks 2, 4, 6, 8, and 10. Training load of each training session of all 10 weeks was assessed by session rating of perceived exertion (RPE) and psychophysiological status by Foster's index. Morning supine HRV (HF% and LF%/HF%) correlated with the training load of the previous day (r = 0.232, r = -0.279, p < 0.05 ). Morning supine to sitting HRV difference (mean R wave to R wave interval (RR), mean heart rate, HF%, SD1) correlated with session RPE of the previous day (r = -0.320, r = 0.301, p < 0.01; r = 0.265, r = -0.270, p < 0.05) but not with Foster's index. Training day/reference day HRV difference (mean RR, SD1) showed the best correlations with session RPE of the previous day (r = -0.384, r = -0.332, p < 0.01) and Foster's index (r = -0.227, r = -0.260, p < 0.05). In conclusion, HRV, and in particular training day/reference day mean RR difference or SD1 difference, could be useful in monitoring training load and psychophysiological status in young male elite gymnasts. PMID:23364293

Sartor, Francesco; Vailati, Emanuele; Valsecchi, Viola; Vailati, Fulvio; La Torre, Antonio

2013-10-01

77

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

PubMed

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

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

2013-03-01

78

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

NASA Technical Reports Server (NTRS)

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

Wiesen, Bernard (Inventor)

2008-01-01

79

Aortic Valve  

MedlinePLUS

... in this category include " xenograft " valves made from animal tissues (most often pig aortic valves), " homograft " or " allograft " valves retrieved from human cadavers, and " pulmonary autograft " valves moved from the patient's pulmonary artery on the right side of the heart to the aortic position ...

80

Plug valve  

DOEpatents

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

Wordin, John J. (Shelley, ID)

1989-01-01

81

Heart rate variability in myocardial infarction patients: effects of exercise training.  

PubMed

Heart rate variability (HRV) is a simple and noninvasive measure that estimates cardiac autonomic modulation, mainly the parasympathetic contribution. Increased sympathetic and/or decreased parasympathetic nervous activity is seen in post-myocardial infarction (MI) patients. Consequently, these patients present reduced HRV, which has been associated with increased risk of adverse events and mortality. Exercise training, recommended as a complementary therapy for patients with cardiovascular disease, has shown numerous beneficial effects. The main aim of the present manuscript was to provide a critical review of studies investigating the effects of exercise training on cardiac autonomic modulation, through HRV, in MI patients and the possible mechanisms involved. Despite conflicting evidence, exercise training appears to be a useful therapeutic intervention to improve the unbalanced autonomic function of MI patients. Finally, the mechanisms involved are not yet well understood, but nitric oxide bioavailability and angiotensin II levels seem to play an important role. PMID:23993292

Oliveira, Nórton Luís; Ribeiro, Fernando; Alves, Alberto Jorge; Teixeira, Madalena; Miranda, Fátima; Oliveira, José

2013-09-01

82

Prosthetic Valves  

Microsoft Academic Search

\\u000a Many challenges are faced by pediatric patients and their surgeons in finding acceptable replacement heart valves for diseased,\\u000a diminutive, or absent native valves. First of the challenges is valve size. Many prosthetic valves available in the market\\u000a today are applicable only to the largest of pediatric patients. Even the smallest of commercially available valves can have\\u000a unacceptable gradients. This can,

Peter D. Wearden

83

Variability of prefrontal neuronal discharges before and after training in a working memory task.  

PubMed

Variability of neural discharges can be revealing about the computations and network properties of neuronal populations during the performance of cognitive tasks. We sought to quantify neuronal variability in the prefrontal cortex of naïve monkeys that were only required to fixate, and to examine how this measure was altered by learning and execution of a working memory task. We therefore performed analysis of a large database of recordings in the same animals, using the same stimuli, before and after training. Our results indicate that the Fano Factor, a measure of variability, differs across neurons depending on their functional properties both before and after learning. Fano Factor generally decreased after learning the task. Variability was modulated by task events and displayed lowest values during the stimulus presentation. Nonetheless, the decrease in variability after training was present even prior to the presentation of any stimuli, in the fixation period. The greatest decreases were observed comparing populations of neurons that exhibited elevated firing rate during the trial events. Our results offer insights on how properties of the prefrontal network are affected by performance of a cognitive task. PMID:22848426

Qi, Xue-Lian; Constantinidis, Christos

2012-01-01

84

Plant Maintenance/Training Manual, (RADL Item 2-37): Section 4. Valves, Book 2 of 2. 10-MWe Solar-Thermal Central-Receiver Pilot Plant. Solar-Facilities Design Integration.  

National Technical Information Service (NTIS)

The valves include motor operated valves, other solenoid valves, safety-relief valves, check and stop check valves, pressure regulator rupture discs, and traps. The valves are listed, and many are individually described and specified. (ERA citation 07:042...

1981-01-01

85

Increased heart rate variability and executive performance after aerobic training in the elderly  

Microsoft Academic Search

This study examined the effects of two short physical training programs on various parameters of heart rate variability (HRV)\\u000a and on executive performance in older people. Twenty-four sedentary men and women aged 65–78 years were randomly assigned\\u000a to an aerobic exercise program or a stretching program three times a week for 12 weeks. Resting HRV was measured in time and\\u000a frequency domains

Cédric T. Albinet; Geoffroy Boucard; Cédric A. Bouquet; Michel Audiffren

2010-01-01

86

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

PubMed

Considerable variation exists between people in the muscle response to resistance training, but there are numerous ways muscle might adapt to overload that might explain this variable response. Therefore, the aim of this study was to quantify the range of responses concerning the training-induced change in maximum voluntary contraction (MVC) knee joint torque, quadriceps femoris (QF) maximum muscle force (F), physiological cross-sectional area (PCSA) and specific tension (F/PCSA). It was hypothesized that the variable change in QF specific tension between individuals would be less than that of MVC. Fifty-three untrained young men performed progressive leg-extension training three times a week for 9 weeks. F was determined from MVC torque, voluntary muscle activation level, antagonist muscle co-activation and patellar tendon moment arm. QF specific tension was established by dividing F by QF PCSA, which was calculated from the ratio of QF muscle volume to muscle fascicle length. MVC torque increased by 26 ± 11% (P < 0.0001; range -1 to 52%), while F increased by 22 ± 11% (P < 0.0001; range -1 to 44%). PCSA increased by 6 ± 4% (P < 0.001; range -3 to 18%) and specific tension increased by 17 ± 11% (P < 0.0001; range -5 to 39%). In conclusion, training-induced changes in F and PCSA varied substantially between individuals, giving rise to greater inter-individual variability in the specific tension response compared to that of MVC. Furthermore, it appears that the change in specific tension is responsible for the variable change in MVC. PMID:20703498

Erskine, Robert M; Jones, David A; Williams, Alun G; Stewart, Claire E; Degens, Hans

2010-12-01

87

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

ERIC Educational Resources Information Center

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

Alpkaya, Ufuk

2013-01-01

88

A Novel Framework and Training Algorithm for Variable-Parameter Hidden Markov Models  

Microsoft Academic Search

We propose a new framework and the associated maximum-likelihood and discriminative training algorithms for the variable-parameter hidden Markov model (VPHMM) whose mean and variance parameters vary as functions of additional environment-dependent conditioning parameters. Our framework differs from the VPHMM proposed by Cui and Gong (2007) in that piecewise spline interpolation instead of global polynomial regression is used to represent the

Dong Yu; Li Deng; Yifan Gong; Alex Acero

2009-01-01

89

The effects of variable speed and drive train component efficiencies on wind turbine energy capture  

SciTech Connect

A wind turbine rotor achieves optimal aerodynamic efficiency at a single tip-speed ratio (TSR). To maintain that optimal TSR and maximize energy capture in the stochastic wind environment, it is necessary to employ variable-speed operation. Conventional constant-speed wind turbines have, in the past, been converted into variable-speed turbines by attaching power electronics to the conventional induction generator and gearbox drive train. Such turbines have shown marginal, if any, improvement in energy capture over their constant-speed counterparts. These discrepancies have been shown to be the result of drive train components that are not optimized for variable-speed operation. Traditional drive trains and power electronic converters are designed to achieve maximum efficiency at full load and speed. However, the main energy producing winds operate the turbine at light load for long periods of time. Because of this, significant losses to efficiency occur. This investigation employs a quasi-static model to demonstrate the dramatic effect that component efficiency curves can have on overall annual energy capture.

Fingersh, L.J.; Robinson, M.C.

1998-05-01

90

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

PubMed

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

Miendlarzewska, Ewa A; Trost, Wiebke J

2013-01-01

91

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

PubMed

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

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

2013-09-01

92

Electromagnetic valve  

US Patent & Trademark Office Database

In an electromagnetic valve, a composite valve case has a cylindrical hollow and a composite valve body formed in spool shape is slidably housed in the cylindrical hollow. The composite valve body has not only an inherent valve function for changing fluid path area according to its movement in the cylindrical hollow but also an armature function for constituting a magnetic circuit. The composite valve case has not only a cylinder function for allowing the valve body to slidably move but also a stator function for constituting a magnetic circuit. The composite valve body and the composite valve case are made of soft magnetic material and are provided at their surfaces with thin hardened layers formed by surface or heat treatment.

2003-12-30

93

Check valve  

DOEpatents

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

Upton, H.A.; Garcia, P.

1999-08-24

94

Check valve  

DOEpatents

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

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

1999-08-24

95

Bypass valve  

Microsoft Academic Search

This patent describes a bypass\\/diverter valve for controlling the flow of fluid from a source to a fluid treatment device such as a water softener. The valve includes a valve housing defining a circular chamber having a cylindrical wall into which three spaced ports open into. Two of the ports form inlet\\/outlet ports communicating with connecting conduits. The third port

P. Halemba; G. S. Ellis; D. W. Crozier

1990-01-01

96

Venous Valves  

NSDL National Science Digital Library

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

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

2009-11-20

97

Fast valve  

DOEpatents

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

Van Dyke, W.J.

1992-04-07

98

Fast valve  

DOEpatents

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.

Van Dyke, William J. (Grafton, VA)

1992-01-01

99

Effect of Supervised, Periodized Exercise Training vs. Self-Directed Training on Lean Body Mass and Other Fitness Variables in Health Club Members.  

PubMed

Storer, TW, Dolezal, BA, Berenc, MN, Timmins, JE, and Cooper, CB. Effect of supervised, periodized exercise training vs. self-directed training on lean body mass and other fitness variables in health club members. J Strength Cond Res 28(7): 1995-2006, 2014-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

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

2014-07-01

100

Flow metering valve  

DOEpatents

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.

Blaedel, K.L.

1983-11-03

101

Flow metering valve  

DOEpatents

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.

Blaedel, Kenneth L. (Dublin, CA)

1985-01-01

102

Effect of a training week on heart rate variability in elite youth rugby league players.  

PubMed

The aim of this study was to examine the influence of weekly training including a competitive game on heart rate (HR) variability (HRV). Youth players (n=9, age 17-20 years) were monitored during daily supine rest (10?min) and standing (8?min), 5 times over 8 days. Heart rate recordings were analysed for time domain, frequency (e.?g. low frequency [LF], high frequency [HF]) domain and non-linear measures of HRV and compared using ANOVA or Friedman's tests. Relationships between HRV and training workloads were examined via Spearman rank rho (?) correlation coefficients. Prior to a game, mean HR was significantly increased and remained elevated until 2 days post-game while parasympathetic modulations (HF) were significantly reduced (p<0.05). The supine to standing change in HRV was significantly reduced for up to 4 days post-game (LF/HF ratio, -?1.0±2.9 vs. -?3.0±1.9, p<0.05). These results confirm that prior to a game, players exhibited reduced parasympathetic and/or predominant sympathetic modulation with the game significantly reducing autonomic responses to standing for up to the following 4 days. Identification of day to day fluctuations in HRV may provide a helpful tool for monitoring player workload to maximise training and game performance. PMID:23740341

Edmonds, R C; Sinclair, W H; Leicht, A S

2013-12-01

103

Variability of island-induced ocean vortex trains, in the Kuroshio region southeast of Taiwan Island  

NASA Astrophysics Data System (ADS)

This study examines the horizontal scale and spatial characteristics of island-induced ocean vortex trains (IOVTs) in the Kuroshio region southeast of Taiwan Island using European remote sensing satellite ERS-1 SAR imagery. US Aqua satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data are used to analyze the sea surface temperature (SST) features of the study area. Seasonal composites of SST images show that the IOVTs are current-induced vortexes rather than wind-induced ones. Furthermore, using the HYbrid Coordinate Ocean Model/Navy Coupled Ocean Data Assimilation (HYCOM/NCODA) system that generated current and sea surface height anomaly data, the temporal and spatial variability of the Green Island IOVTs is analyzed. The variability of IOVTs within this region shows a distinct seasonality. This seasonal variability of IOVTs is closely associated with the shoreward shift of Kuroshio mainstream driven by the winter northeasterly monsoon. This scenario is verified by vector empirical orthogonal function analysis focused on the weak IOVT period in 2012. In addition to meandering of the Kuroshio, westward-propagating mesoscale eddies and the arrival of typhoons play an important role in modifying the variability of IOVTs at intraseasonal timescale.

Zheng, Zhe-Wen; Zheng, Quanan

2014-06-01

104

Valve lock  

NASA Astrophysics Data System (ADS)

A valve security lock is provided which secures a double union ball valve. The lock is formed from a band inserted through slits in a tube, with that combination being positioned over the valve stem to be secured, and the ends of the band wrapped around the circumference of the double union ball valve. The apparatus is secured around the double union ball valve by insertion of the shank of a lock of known kind through holes in the ends of the band. In a fluid control system, the valve security lock provides a highly visible means to prevent accidental turn-ons or turn-offs during system maintenance, but which can be easily disengaged by persons having the key or combination to the shank type lock.

Burley, Richard K.; Guirguis, Kamal S.

1992-11-01

105

Analysis and modelling of variability and covariability of population spike trains across multiple time scales.  

PubMed

As multi-electrode and imaging technology begin to provide us with simultaneous recordings of large neuronal populations, new methods for modelling such data must also be developed. We present a model of responses to repeated trials of a sensory stimulus based on thresholded Gaussian processes that allows for analysis and modelling of variability and covariability of population spike trains across multiple time scales. The model framework can be used to specify the values of many different variability measures including spike timing precision across trials, coefficient of variation of the interspike interval distribution, and Fano factor of spike counts for individual neurons, as well as signal and noise correlations and correlations of spike counts across multiple neurons. Using both simulated data and data from different stages of the mammalian auditory pathway, we demonstrate the range of possible independent manipulations of different variability measures, and explore how this range depends on the sensory stimulus. The model provides a powerful framework for the study of experimental and surrogate data and for analyzing dependencies between different statistical properties of neuronal populations. PMID:22578115

Lyamzin, Dmitry R; Garcia-Lazaro, Jose A; Lesica, Nicholas A

2012-01-01

106

Flow valve  

SciTech Connect

A flow valve with a flow passage which exhibits a working flow path and a backflow path, having a pressure relief valve which consists of a spring-loaded closing device and a valve seat located to shut off the backflow path below a certain pressure limit, and with a back-pressure valve comprising a closing device and a valve seat, this closing device being removable from the valve seat by means of the working pressure, thus clearing the working flow path. In order to simplify the construction and to obtain a large cross-sectional passage area at a given external dimension of the valve housing, both flow paths are conducted via a common valve seat, and the closing device can be moved away from the valve seat by means of working pressure which moves the closing device in the working flow direction from its closing position, in which both flow paths are shut off, into a first open position, in which the closing device clears the working flow path, and furthermore, the closing device can be moved away from its closing position to the backflow direction by means of the backflow pressure, thus pushing it against the tension of a spring into a second open position in which it clears the back-flow path.

Brunner, R.

1985-03-12

107

training  

Microsoft Academic Search

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

LAWRENCE L. SPRIET; MARTIN J. GIBALA

108

Fast-Acting Valve.  

National Technical Information Service (NTIS)

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the a...

B. V. Wojciechowski R. J. Pegg

2003-01-01

109

Improved Merge Valve  

NASA Technical Reports Server (NTRS)

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.

George-Falvy, Dez

1992-01-01

110

Tensiometer Irrigation Valve.  

National Technical Information Service (NTIS)

A flow controller device includes a valve assembly connected with a tensiometer to provide automatic control of flow of water for irrigation, including variable control of the rate of flow according to the matric tension of the soil for water. The tensiom...

D. L. Peterson D. M. Glenn

1991-01-01

111

Depressurization valve  

DOEpatents

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.

Skoda, George I. (Santa Clara, CA)

1989-01-01

112

Self-regulating valve  

DOEpatents

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.

Humphreys, D.A.

1982-07-20

113

Generation of Picosecond Electron-Bunch Trains with Variable Spacing Using a Multi-Pulse Photocathode Laser  

SciTech Connect

We demonstrate the generation of a train of electron bunches with variable spacing at the Argonne Wakefield Accelerator. The photocathode ultraviolet laser pulse consists of a train of four pulses produced via polarization splitting using two alpha-BBO crystals. The photoemitted electron bunches are then manipulated in a horizontally-bending dogleg with variable longitudinal dispersion. A downstream vertically-deflecting cavity is then used to diagnose the temporal profile of the electron beam. The generation of a train composed of four bunches with tunable spacing is demonstrated. Such a train of bunch could have application to, e.g., the resonant excitation of wakefield in dielectric-lined structures. We have presented preliminary measurements on a simple technique to generate a train of electron bunches with variable separation. In the initial experiment appreciable density modulation down to wavelengths of {approx}1.8 mm (corresponding to a temporal separation of {approx}6 ps) were achieved for a total charge of 0.5 nC. Finding ways to reach smaller separations is being explored with the help of numerical simulations and will be presented elsewhere.

Conde, M.; Gai, W.; /Argonne; Jing, C.; /Euclid TechLabs /Argonne; Konecny, R.; Liu, W.; /Argonne; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Northern Illinois U. /Fermilab; Power, J.G.; /Argonne; Rihaoui, M.; /Northern Illinois U.; Yusof, Z.; /Argonne

2012-07-08

114

Nuclear radiation actuated valve  

DOEpatents

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.

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

1985-01-01

115

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

PubMed

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

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

2014-07-01

116

Atrioventricular Valves  

NSDL National Science Digital Library

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

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

2009-11-20

117

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

Microsoft Academic Search

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

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

2002-01-01

118

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

ERIC Educational Resources Information Center

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

Norman, D. A.; And Others

119

Bypass valve  

SciTech Connect

This patent describes a bypass/diverter valve for controlling the flow of fluid from a source to a fluid treatment device such as a water softener. The valve includes a valve housing defining a circular chamber having a cylindrical wall into which three spaced ports open into. Two of the ports form inlet/outlet ports communicating with connecting conduits. The third port forms an intermediate port that communicates with the input to the water softener. The valve housing also defines a second intermediate port communicating with the output of the water softener and which communicates with the valve chamber through a passive arrangement. A plug-like valving member is rotatable within the chamber and includes a recess which together with the chamber wall defines a passage for selectively communicating one of the inlet/outlet ports with the first intermediate port while concurrently communicating the other inlet/outlet port with the second intermediate port or alternately for communicating the first inlet/outlet port with the first intermediate port.

Halemba, P.; Ellis, G.S.; Crozier, D.W.

1990-11-27

120

Improvement of circadian rhythm of heart rate variability by eurythmy therapy training.  

PubMed

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

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

2013-01-01

121

Testing mediator variables in a resistance training intervention for obese adults with type 2 diabetes.  

PubMed

A poor understanding of behaviour change mechanisms has hindered the development of effective physical activity interventions. The aim of this study was to identify potential mediators of change in a home-based resistance training (RT) program for obese individuals with type 2 diabetes. Obese individuals with type 2 diabetes (N?=?48) were randomly allocated to either an RT intervention (n?=?27) or a control group (n?=?21) for the 16-week study period. The study sample included 16 men and 32 women and the mean age of participants was 54.4 (±11.7) years. Participants in the RT group received a multi-gym and dumbbells and home supervision from a certified personal trainer. RT behaviour was measured using a modified Godin Leisure Time Questionnaire. Social-cognitive constructs were measured and tested in a mediating variable framework using a product-of-coefficients test. The intervention had a significant effect on RT behaviour (p?

Lubans, David R; Plotnikoff, Ronald C; Jung, Mary; Eves, Neil; Sigal, Ron

2012-01-01

122

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

PubMed Central

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

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

2013-01-01

123

Comparing Methods for Multivariate Classifier Training Variable Selection using the Search for the Scalar Top Quark as a Case Study.  

NASA Astrophysics Data System (ADS)

We look for a way to automate the process of training variable selection when applying multivariate event classifiers to the search for new phenomenon in high energy physics experiments. The Dø collaboration recently completed a search for the Supersymmetric partner of the top quark in the two muons, two jets, and missing transverse energy final state. We use the Monte Carlo events representing the signal and the background from this search as the basis for our case study. We begin with the computationally expensive, O(2^n), method of testing the classifier for all variable combinations and then selecting the one combination which gives the best expected signal sensitivity. We then compare this ``best'' sensitivity to the sensitivities of the classifier when trained using variable combinations suggested by less expensive methods such as sequential forward selection, chi-squared and K-S testing, and physicist intuition. Even in this age of grid computing, the total number of variables which can be tested is limited. In our case, we were limited to considering eleven variables. A less expensive method of variable selection would not only free up computing resources, it would enable us to consider a much larger set of variables for use in the multivariate classifier.

Mackin, Dennis

2007-10-01

124

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

Microsoft Academic Search

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

A. Stahle; R. Nordlander; L. Bergfeldt

125

The effect of physical training on heart rate variability in healthy children: a systematic review with meta-analysis.  

PubMed

The positive effects of physical training on heart rate variability (HRV) in healthy adults are widely recognized; however, the responsiveness to training in healthy children has not yet been established. The aim of this study was to determine the influence of physical training on HRV in prepubertal healthy children. Systematic computerized searches were performed from 1950 to 2012 in the following databases: Medline, Embase, Cinahl, Lilacs, Scielo, SportDiscus, ProQuest; Web of Science; PEDro; Academic Search Premier and the Cochrane Library. The key words used were: heart rate variability, autonomic nervous system, exercise training, physical activity, continuous exercise, intermittent exercise, children, prepubescent, adolescents, and healthy. Although the database search initially identified 6,164 studies, after removing duplicates and excluding by title the number was 148, however, only 2 studies were included in this systematic review. The meta-analysis compared the experimental group (n = 29) with the control group (n = 28) for the HRV parameters: RR intervals, SDNN, RMSSD, pNN50, LF (log), HF (log), LF/HF and Total Power (log). The meta-analysis demonstrated similar HRV indices between both the experimental and control groups. In conclusion, the available results from randomized controlled trials do not support the hypothesis that physical training improves HRV in healthy children[AUQ2]. PMID:24722980

da Silva, Carla Cristiane; Pereira, Ligia Maxwell; Cardoso, Jefferson Rosa; Moore, Jonathan Patrick; Nakamura, Fábio Yuzo

2014-05-01

126

Titanium in Engine Valve Systems  

NASA Astrophysics Data System (ADS)

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

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

1987-03-01

127

Individual training-load and aerobic-fitness variables in premiership soccer players during the precompetitive season.  

PubMed

The aim of this study was to examine the association between individual measures of internal training load (training impulse [TRIMPi]) and aerobic-fitness and performance variables in premiership male soccer players. Eighteen Premiership soccer players (age 28.4 ± 3.2 years, height 182 ± 5.3 cm, body mass 79.9 ± 5.5 kg) performed treadmill tests for VO(2max) and ventilatory threshold (VT) and speed at blood-lactate concentration of 4 mmol·L(-1) (S4) on separate days pre and post 8 weeks of training (preseason). The Yo-Yo Intermittent recovery test (Yo-Yo IR1) performance was assessed pre and post preseason training as well. The TRIMPi was calculated using individual lactate and heart-rate profiles and assessed in each training session (n = 900). The results showed that TRIMPi was large to very-large associated with percentage changes in VO(2max) (r = 0.77, p = 0.002), VT (r = 0.78, p = 0.002), S4 (r = 0.64, p = 0.004), and Yo-Yo IR1 performance (r = 0.69, p = 0.009). Regression analyses showed that a weekly TRIMPi >500 AU was necessary to warrant improvements in aerobic fitness and performance in premiership male soccer players during the precompetitive season. It is concluded that TRIMPi is a valid and viable tool to guide training prescription in male premiership soccer players during the preseason. PMID:22648141

Manzi, Vincenzo; Bovenzi, Antonio; Franco Impellizzeri, Maria; Carminati, Ivan; Castagna, Carlo

2013-03-01

128

Problem: Heart Valve Regurgitation  

MedlinePLUS

... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Regurgitation Updated:Apr 26,2013 What ... last reviewed on 02/18/13. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

129

Problem: Heart Valve Stenosis  

MedlinePLUS

... Pressure High Blood Pressure Tools & Resources Stroke More Problem: Heart Valve Stenosis Updated:Mar 14,2014 About ... last reviewed on 02/18/13. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

130

TRAINING COMMUNITY VOLUTEERS IN PREVENTING ALCOHOLISM AND DRUG ADDICTION : A BASIC PROGRAMME AND ITS IMPACT ON CERTAIN VARIABLES  

PubMed Central

A study was conducted on 19 community volunteers and the training module they underwent is presented. The subjects were given 7 days in-training with the objectives of imparting knowledge ana skill to identify and motivate alcohol and drug dependent person, to motivate them and their family to seek treatment to provide social support to them and to organise prevention programmes in the community. Their knowledge, skills and attitudes have shown significant improvement and change as a result to training. Extraversion was found to be significantly related to change in all the above variables, psychoticism was related to attitude and self-esteem was related to improvement in skills. Need for under taking further research in this area is also emphasized.

Manickam, L.S.S.

1997-01-01

131

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

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

132

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

Code of Federal Regulations, 2010 CFR

...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...

2010-10-01

133

Piezoelectric valve  

DOEpatents

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.

Petrenko, Serhiy Fedorovich

2013-01-15

134

Management turnover expectations: a variable to explain company readiness to engage in continuous management training  

Microsoft Academic Search

What makes companies give their support to Continuous Management Training (CMT) and why, on occasion, do they block its progress? If a company thinks its managers might leave in the near future, would there be reasons for it to provide continuous training of these professionals? Do companies interpret all likely resignations in the same way? We attempt to provide an

Jon Landeta; Jon Barrutia; Jon Hoyos

2009-01-01

135

Influence of training and a maximal exercise test in analytical variability of muscular, hepatic, and cardiovascular biochemical variables.  

PubMed

Abstract Short, middle, and long-term exercise, as well as the relative intensity of the physical effort, may influence a broad array of laboratory results, and it is thereby of pivotal importance to appropriately differentiate the 'physiologic' from the 'pathological' effects of exercise. Therefore, the values of some biomarkers in physically active subjects may be cautiously interpreted since the results may fall outside the conventional reference ranges. It has been demonstrated that middle and long-term endurance and/or strenuous exercise triggers transient elevations of muscular and cardiac biomarkers. However, no data have been published about the effect of short-term maximal exercise test on the most useful muscular, hepatic and cardiovascular biomarkers. The aim of the present study was to assess the baseline concentrations of muscular, hepatic, and cardiovascular makers between trained and untrained subjects, along with changes induced by maximal exercise test. We measured C reactive protein (CRP), procalcitonin (PCT), gamma glutamyltransferase (GGT), creatine kinase-MB isoenzyme (CK-MB), Hs-TnT, NT-proBNP, CK, LDH, AST, and ALT in serum samples of physically active (trained) and physically inactive (sedentary) male collected before, immediately after a maximal exercise test and after a 30-min recovery period. Trained subjects tend to have significantly raised base concentrations of CK, CK-MB, ALT, and LDH compared to sedentary individuals, and this can be clearly interpreted as a mild injury of skeletal muscle. A single maximal exercise was also effective to transiently increase the concentrations of NT-proBNP, but not those of Hs-TnT, thus suggesting that the cardiac involvement is mostly benign in nature. PMID:24484196

Romagnoli, Marco; Alis, Rafael; Aloe, Rosalia; Salvagno, Gian Luca; Basterra, Javier; Pareja-Galeano, Helios; Sanchis-Gomar, Fabian; Lippi, Giuseppe

2014-04-01

136

Miniature piezo electric vacuum inlet valve  

DOEpatents

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

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

1998-03-24

137

Miniature piezo electric vacuum inlet valve  

DOEpatents

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.

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

1998-03-24

138

Plasma valve  

DOEpatents

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.

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

139

Servo Valve.  

National Technical Information Service (NTIS)

The development and characteristics of a servo valve for controlling the flow of gaseous or hydraulic fluids to servo motors are discussed. A venturi-shaped arrangement is used in which the pressure change to the servo is as great as twice the supply pres...

H. D. Garner

1974-01-01

140

Fluid valve with wide temperature range  

NASA Technical Reports Server (NTRS)

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

Kast, Howard Berdolt (Inventor)

1976-01-01

141

Analysis of the Impact of Early Surgery on In-hospital Mortality of Native Valve Endocarditis: Use of Propensity Score and Instrumental Variable Methods to Adjust for Treatment Selection Bias  

PubMed Central

Background The impact of early surgery on mortality in patients with native valve endocarditis (NVE) is unresolved. This study seeks to evaluate valve surgery compared to medical therapy for NVE, and to identify characteristics of patients who are most likely to benefit from early surgery. Methods and Results Using a prospective, multinational cohort of patients with definite NVE, the effect of early surgery on in-hospital mortality was assessed using propensity-based matching adjusting for survivor bias, and instrumental variable analysis. Patients were stratified by propensity quintile, paravalvular complications, valve perforation, systemic embolization, stroke, Staphylococcus aureus infection and congestive heart failure. Of the 1552 patients with NVE, 720 (46%) underwent early surgery and 832 (54%) were treated with medical therapy. Compared to medical therapy, early surgery was associated with a significant reduction in mortality in the overall cohort (12.1% [87/720] vs. 20.7% [172/832]) and after propensity-based matching and adjustment for survivor bias (absolute risk reduction (ARR) = -5.9 %; p<0.001). Using a combined instrument, the instrumental variable adjusted ARR in mortality associated with early surgery was -11.2% (p<0.001). In sub-group analysis, surgery was found to confer a survival benefit compared to medical therapy among patients with a higher propensity for surgery (ARR= -10.9% for quintiles 4 and 5; p=0.002); those with paravalvular complications (ARR= -17.3 %; p<0.001), systemic embolization (ARR= -12.9%; p=0.002), S aureus NVE (ARR= -20.1%; p<0.001) and stroke (ARR= -13%; p=0.02) but not with valve perforation or congestive heart failure. Conclusions Early surgery for NVE is associated with an in-hospital mortality benefit compared to medical therapy alone.

Lalani, Tahaniyat; Cabell, Christopher H; Benjamin, Daniel K; Lasca, Ovidiu; Naber, Christoph; Fowler, Vance G.; Corey, G Ralph; Chu, Vivian H; Fenely, Michael; Pachirat, Orathai; Tan, Ru-San; Watkin, Richard; Ionac, Adina; Moreno, Asuncion; Mestres, Carlos A; Casabe, Jose; Chipigina, Natalia; Eisen, Damon P; Spelman, Denis; Delahaye, Francois; Peterson, Gail; Olaison, Lars; Wang, Andrew

2013-01-01

142

Effects of Autogenic-Feedback Training on Motion Sickness Severity and Heart Rate Variability in Astronauts.  

National Technical Information Service (NTIS)

Space motion sickness (SMS) affects 50 percent of all people during early days of spaceflight. This study describes the results of two Shuttle flight experiments in which autogenic-feedback training (AFT), a physiological conditioning method, was tested a...

W. B. Toscano P. S. Cowings

1994-01-01

143

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

Microsoft Academic Search

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

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

144

Check all SCHE Supply Purge Check Valves to Prevent Back Flow from SCHE into Helium Supply  

SciTech Connect

These valves are 1/2-inch check valves used to prevent SCHe backflow into the Helium System if pressure in the Helium System drops below the pressure of the control valve downstream of the SCHe supply bottles. (14 psig in trains A and B and 2 psig in trains C and D).

MISKA, C.R.

2000-10-23

145

Free Field Vibrations during the Passage of a Thalys High-Speed Train at Variable Speed  

NASA Astrophysics Data System (ADS)

During homologation tests of the high-speed train (HST) track between Brussels and Paris, free field vibrations and track response have been measured during the passage of a Thalys HST at speeds varying between 223 and 314 km/h. These experimental data are complementary to the other, but scarce, data sets published in the literature. Apart from illustrating the physical phenomena involved, this data set can be used for the validation of numerical prediction models for train-induced vibrations.

DEGRANDE, G.; SCHILLEMANS, L.

2001-10-01

146

High speed exhaust gas recirculation valve  

SciTech Connect

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.

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

2005-01-18

147

Rubber valve seal with tough skin  

NASA Technical Reports Server (NTRS)

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

Martin, J. W.

1979-01-01

148

A novel optimization procedure for training of fuzzy inference systems by combining variable structure systems technique and Levenberg-Marquardt algorithm  

Microsoft Academic Search

This paper presents a novel training algorithm for fuzzy inference systems. The algorithm combines the Levenberg-Marquardt algorithm with variable structure systems approach. The combination is performed by expressing the parameter update rule in continuous time and application of sliding mode control method to the gradient based training procedure. The proposed combination therefore exhibits a degree of robustness to the unmodeled

Mehmet Önder Efe; Okyay Kaynak

2001-01-01

149

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

PubMed

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

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

2014-07-01

150

Magnetically operated check valve  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

151

Magnetically operated check valve  

NASA Astrophysics Data System (ADS)

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.

Morris, Brian G.; Bozeman, Richard J., Jr.

1994-06-01

152

Mechanical heart valves: Changes in patient survival and valve failure rates  

Microsoft Academic Search

The effect of patient related variables and mechanical heart valve substitutes on survival and valve failure rates was studied\\u000a in 2,778 patients operated between 1966 and 1986. Of these 48.2% were operated without cardioplegic protection (phase I) and\\u000a 51.8% thereafter (phase II). Mitral vlave replacement (MVR) was performed in 1,257 patients (phase I: 51.58%, phase II: 48.42%);\\u000a aortic valve replacement

T. K. Kaul; J. L. Mercer; D. R. Ramsdale

1992-01-01

153

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 ...

154

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

PubMed

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

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

2013-11-01

155

The Role of Aerobic and Anaerobic Training Programs on CD34+ Stem Cells and Chosen Physiological Variables  

PubMed Central

Exercise is one of the most powerful non-pharmacological strategies, which can affect nearly all cells and organs in the body. Changes in the behavior of adult stem cells have been shown to occur in response to exercise. Exercise may act on regenerative potential of tissues by altering the ability to generate new stem cells and differentiated cells that are able to carry out tissue specific functions. The purpose of this study was to reveal the role of aerobic and anaerobic training programs on CD34+ Stem Cells and chosen physiological variables. Twenty healthy male athletes aged 18–24 years were recruited for this study. Healthy low active males and BMI matched participants (n=10) aged 20–22 years were recruited as controls. Aerobic and anaerobic training programs for 12 weeks were conducted. VO2max pulse observation was carried out using the Astrand Rhyming protocol. RBCs, WBCs, HB and hematocrit were estimated using a coulter counter, lactate by the Accusport apparatus, CD34+ stem cells by flow cytometry. VO2max was increased significantly in case of the aerobic training program compared to anaerobic one (62±2.2 ml/kg/min vs. 54±2.1 ml/kg/min). Haemotological values increased significantly in the anaerobic program when compared to the aerobic one, RBCs (5.3±0.3 and 4.9±0.2 mln/ul), WBCs (6.6±0.5 and 6.1±0.4 thous/ul), HB (15.4±0.4 and 14.2±0.5 g/de), Hematocrit (4.6±1.2 and 4.4±1.1 %), CD34+ stem cells count increased significantly in case of the anaerobic program compared to the aerobic (251.6±21.64 and 130±14.61) and sedentary one (172±24.10). These findings suggest that anaerobic training programs provoke better adaptation to exercise and stem cell counts may differ between trained and sedentary subjects. Circulating immature cells are likely to be involved in angiogenesis and repair process, both mechanisms being associated with strenuous exercise. Knowledge of the physiological effects of training on stem cells might be of potential clinical use.

Shalaby, Mohammed Nader; Saad, Mohammed; Akar, Samy; Reda, Mubarak Abdelreda Ali; Shalgham, Ahmed

2012-01-01

156

Stage cementing valve  

SciTech Connect

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.

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

1989-11-14

157

Rotary pneumatic valve  

DOEpatents

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

Hardee, Harry C. (Albuquerque, NM)

1991-01-01

158

Improved plug valve  

DOEpatents

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

Wordin, J.J.

1986-05-09

159

Liquid rocket valve components  

NASA Technical Reports Server (NTRS)

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.

1973-01-01

160

Throttle valve controlling apparatus  

SciTech Connect

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.

Ejiri, Y.; Kamifuji, H.

1986-07-22

161

Vacuum breaker valve assembly  

DOEpatents

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.

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

1999-04-27

162

Vacuum breaker valve assembly  

DOEpatents

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.

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

1999-04-27

163

Bellows sealed plug valve  

DOEpatents

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

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

1990-01-01

164

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

PubMed Central

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.

2014-01-01

165

Valve for fluid control  

DOEpatents

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.

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

166

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

PubMed

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

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

2012-01-01

167

Changes in R–R variability before and after endurance training measured by power spectral analysis and by the effect of isometric muscle contraction  

Microsoft Academic Search

The long-term conditioning effects of physical training on cardiorespiratory interaction in 11 young healthy males were studied.\\u000a Significant increases in maximum oxygen uptake (V?O2max)(PP<0.05) were achieved in all subjects following a 6-week training programme consisting of cycling for 25min each day at a work\\u000a level that increased heart rate to 85% of maximum. Heart rate variability, measured as the differences

M. Al-Ani; S. M. Munir; M. White; J. Townend; J. H. Coote

1996-01-01

168

Effects of music tempo on performance, psychological, and physiological variables during 20 km cycling in well-trained cyclists.  

PubMed

Few studies have investigated the effects of music on trained athletes during high intensity endurance tasks. Therefore, this study investigated the effects of different music tempi on performance, psychological, and physiological responses of well-trained cyclists to time trial cycling. 10 male road cyclists (M age = 35 yr., SD = 7), with a minimum of three years racing experience, performed four 20-km time trials on a Computrainer Pro 3D indoor cycle trainer over a period of four weeks. The time-trials were spaced one week apart. The music conditions for each trial were randomised between fast-tempo (140 bpm), medium-tempo (120 bpm), slow-tempo (100 bpm), and no music. Performance (completion time, power output, average speed and cadence), physiological (heart rate, oxygen consumption, breathing frequency and respiratory exchange ratio), psychophysical (RPE), and psychological (mood states) data were collected for each trial. Results indicated no significant changes in performance, physiological, or psychophysical variables. Total mood disturbance and tension increased significantly in the fast-tempo trial when compared with medium and no-music conditions. PMID:24611252

2013-10-01

169

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

PubMed

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

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

2013-11-01

170

Well cementing valve  

SciTech Connect

A well cementing valve is described for a well tubing string, comprising: a tubular mandrel having at least one mandrel port communicating the interior of the mandrel with the exterior thereof, the mandrel being adapted to be made-up in the well tubing string; an axially movable sleeve valve initially covering the mandrel port on the mandrel exterior, the sleeve valve having a pressure responsive seal area subject to fluid pressure in the mandrel for moving the sleeve valve; an axially slidable protective sleeve initially surrounding the mandrel and the sleeve valve; and shear means connecting the protective sleeve to the sleeve valve to restrain the sleeve valve against axial displacement, the pressure responsive seal area on the sleeve valve being operable to apply a shearing load on the shear means, permitting an axial displacement of the protective sleeve and an opposite axial displacement of the sleeve valve to open the port.

VanWormer, R.A.; Baugh, J.L.

1986-07-29

171

Circulating valve for wells  

SciTech Connect

A circulating (kill) valve for hot, high pressure wells includes a valve assembly to be positioned in an open-ended tubular-shaped side-pocket housing of a mandrel connected into a well tubing string. The valve assembly includes an open-ended cylindrical valve body provided with an interior sealing seat and spaced-apart side openings. A valve element is arranged within the valve body and is urged by unbalanced pressures to the open or closed position depending on the direction of the pressure imbalance. In the closed position, a sealing surface on the exterior of the valve element engages and seals with the lower interior sealing seat of the valve body. A ported access to the inner well string pressure permits that pressure to urge the valve element to the closed position. Such pressure may be overcome by pressure imbalance when fluid pressure exterior of the tubing string forces the valve element upward from its seat. A wiper seal is arranged on the interior of the valve body and engages the outer surface of the valve element. A pressure operated down-hole circulating (kill) valve is described which alleviates the primary causes of problems with previous valves. 10 claims.

O'Connor, J.A. III.; Holland, W.E.; Burley, J.D.; Rogers, R.D.; Watkins, F.E.

1982-11-23

172

Design and development of a novel balancer with variable difficulty for training and evaluation.  

PubMed

This paper presents a novel, portable and cost-effective balance trainer with the necessary important features to improve the reach of rehabilitation to the masses. There are three factors that contribute to a person's ability to maintain standing balance: Proprioceptive feedback (from the joints), vision, and the vestibular system. These systems can be affected by injury, infection, or brain damage caused by stroke. One example of such injuries is ankle injury. A large focus of the physiotherapy and sports medicine community is using postural-control tasks to prevent, assess and rehabilitate patients. Unfortunately, there are presently two extreme ends of balance training devices. On one end, there is high-end equipment which only large hospitals are capable of buying. On the other end are the simple balance boards which offer limited features. To develop the new balance trainer - the Pro.Balance - therapists at the Singapore General Hospital drafted a new 'wish list' of requirements. The prototype was built at the Nanyang Technological University, Singapore, and was commercialized by Lab Rehab Pte Ltd as the Pro.Balance. The device has a small footprint, incorporating only the most important and frequently used functions. These functions include being able to provide different levels of difficulty, setting different difficulties in different directions, the storing of a patient's performance, real-time visual feedback to aid the patient and different types of modes for different purposes. Springs are used to vary the amount of supporting moments, thus varying the difficulty levels. This paper describes the design and features of the Pro.Balance. PMID:19117193

Ang, W T; Tan, U-X; Tan, H G; Myo, T; Ng, C K; Koh, K L; Cheam, B S

2008-11-01

173

Quickly Removable Valve  

NASA Technical Reports Server (NTRS)

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

Robbins, John S.

1988-01-01

174

Quadricuspid semilunar valves.  

PubMed

Forty-seven cases of quadricuspid semilunar valves which were autopsied were reviewed. The ratio of quadricuspid pulmonic valve to quadricuspid aortic valve was 5:1. Among the 35 patients with quadricuspid pulmonic valves, there were ten patients with clinical and pathologic evidence of coexisting congenital cardiac defects, eight of which resulted in severe cyanotic heart disease in infancy. In the remaining 25 patients the quadricuspid pulmonic valve was an incidental finding at autopsy. Three of the seven patients with quadricuspid aortic valves had aortic insufficiency, while the remaining four had no other clinical or pathologic evidence of congenital heart disease. PMID:884980

Davia, J E; Fenoglio, J J; DeCastro, C M; McAllister, H A; Cheitlin, M D

1977-08-01

175

Optimization of Valve Disc Using Orthogonal Array and Kriging Model  

NASA Astrophysics Data System (ADS)

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.

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

2008-10-01

176

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

PubMed

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. PMID:19391776

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

2009-02-01

177

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

NASA Astrophysics Data System (ADS)

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.

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

2009-02-01

178

Rorschach Variables and Big Five Scales as Predictors of Military Training Completion: A Replication Study of the Selection of Candidates to the Naval Special Forces in Norway  

Microsoft Academic Search

We tested 140 male candidates at the Naval Special Forces (NFS) of Norway on the Rorschach (Exner, 2003; Rorschach, 1921\\/1942) and the Norwegian version of the Big Five personality dimensions (Engvik & Føllesdal, 2005). Rorschach variables significantly correlated with training completion (effect sizes of re = .14–.25), whereas none of the Big Five factors or facets did. The combination of

Ellen Hartmann; Cato Grønnerød

2009-01-01

179

Valve Health Monitor (VHM)  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

180

Mitral valve surgery - open  

MedlinePLUS

... the rest of your life. Biological -- made of human or animal tissue. These valves last 10-12 years. You ... occur, but this is rare. Valves made from human or animal tissue fail over time, but have a lower ...

181

Overflow control valve  

DOEpatents

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

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

1984-07-24

182

Aerodynamic Shutoff Valve  

NASA Technical Reports Server (NTRS)

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.

Horstman, Raymond H.

1992-01-01

183

Stemless Ball Valve  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

184

Lightweight Motorized Valve  

NASA Technical Reports Server (NTRS)

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

Gonzalez, R.; Vandewalle, J.

1986-01-01

185

High Vacuum Valve.  

National Technical Information Service (NTIS)

The metal-to-metal seal vacuum valve is provided with a bellows which aids in preventing leakage through the housing cover and about the stem. The inner surface of the valve housing is provided with a metal valve seat having a relatively sharp edge around...

J. M. Frame

1965-01-01

186

Stop Valve Mechanism.  

National Technical Information Service (NTIS)

The valve mechanism controls the flow of fluids and functions as a hydraulic fuse. The valve operates automatically to interrupt the flow of a fluid in response to a decrease of the fluid pressure in its outlet circuit. The valve is located in the main pa...

P. I. Evans

1964-01-01

187

Lock For Valve Stem  

NASA Technical Reports Server (NTRS)

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.

Burley, Richard K.; Guirguis, Kamal S.

1991-01-01

188

Dump valve assembly  

DOEpatents

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.

Owen, T.J.

1984-01-01

189

Liquid rocket valve assemblies  

NASA Technical Reports Server (NTRS)

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.

1973-01-01

190

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

NASA Astrophysics Data System (ADS)

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.

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

1986-03-01

191

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

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

192

An experimental method for validating compressor valve vibration theory  

NASA Astrophysics Data System (ADS)

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

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

2006-07-01

193

Ride Comfort Analysis based on Heart Rate and Blood Pressure Variability according to Changed Tilting Angle at Tilting Train Simulator  

Microsoft Academic Search

The Korea is consisted of 70% mountain terrain and at existing rail road, it is many of curve railroad segment naturally. If tilting train is applied, it is unnecessary that speed of tilting train is supposed to decelerating in the curve railroad segment. As you get a hunch as term 'tilting', the biggest feature of tilting train is the thing

Kwangsoo Shin; Youngbum Lee; Yongsoo Song; Sungho Han; Myoungho Lee

2008-01-01

194

Mitral valve replacement with ball valve prostheses  

PubMed Central

Our experience with ball valve replacement of the mitral valve during the past decade is presented in terms that allow comparison with other techniques. The use of such prostheses is characterized by ease of implantation, with an overall operative mortality of 11 per cent for isolated mitral replacement and 13 per cent for multiple valve replacement. The operative mortality for isolated mitral valve replacement during 1969 and thus far in 1970 has been nil. The late mortality was 13 per cent for isolated mitral replacement and 20 per cent for multiple valve replacement. Forty-three per cent of the total late deaths were clearly unrelated to the prosthetic device itself. The overall incidence of late infection and leak is less than 1 per cent and the immediate haemodynamic benefit is not altered by loss of structural integrity of the prosthesis. The most serious problem after mitral valve replacement with the ball valve prosthesis is that of thromboembolic complications. While thrombotic stenosis of the prosthesis is a rarity, embolic episodes, usually cerebral in type, have been noted in 63 per cent of the patients surviving mitral valve replacement with the earliest model ball valve from August 1960 to February 1966. Improvements in valve design have resulted in a remarkable decrease in this incidence as examined by actuarial techniques and taking into account the duration of follow-up. The extension of the cloth sewing margins to the orifice of the valve while maintaining a metallic orifice and metallic cage (Model 6120) resulted in a drop of the thromboembolic rate to 17 per cent from April 1965 to April 1969. The development of the totally cloth-covered prosthesis has further improved these results, with only one thromboembolic complication after isolated mitral valve replacement with the Model 6310 valve in a series of 66 consecutive patients. In clinical practice this has resulted in the avoidance of the use of anticoagulant therapy in patients in whom for a variety of reasons this carries an increased hazard. With further follow-up it may be possible to discontinue the routine use of anticoagulants. Images

Starr, Albert

1971-01-01

195

Heart Valve Prostheses  

Microsoft Academic Search

\\u000a Prosthetic heart valves may be mechanical or bioprosthetic. Mechanical valves, which are composed primarily of metal or carbon\\u000a alloys, are classified according to their design as ball-caged, single-tilting-disc, or bileaflet-tilting-disc valves (Fig.\\u000a 9.1). In ball-caged valves, the occluder is a sphere that is contained by a metal “cage” when the valve is in its open position,\\u000a and fills the orifice

Luigi P. Badano; Rosa Sicari

196

Compact valve actuation mechanism  

NASA Technical Reports Server (NTRS)

A valve actuation device. The device may include a free floating valve bridge movably supported within a cavity in the engine housing. The bridge may be provided with a cavity and an orifice arrangement for pumping gases entrained with lubricating fluid toward the piston stems as the bridge reciprocates back and forth. The device may also include a rocker arm that has a U-shaped cross-sectional shape for receiving at least a portion of the valve bridge, valve stem valve spring and spring retainer therein. The rocker arm may be provided with lubrication passages for directing lubrication to the point wherein it is pivotally affixed to the engine housing.

Brogdon, James William (Inventor); Gill, David Keith (Inventor)

2000-01-01

197

Finite element analysis of flow in a hydraulic pressure valve  

Microsoft Academic Search

The paper describes a finite element study of laminar flow of oil through a hydraulic pressure-relief valve of the differential-angle type used in a variable compression ratio piston of an internal combustion engine. The model simulates an experimental setup used to obtain the performance characteristics of the valve under steady-state conditions. The velocity and pressure distributions through the valve and

M. R. Mokhtarzadeh-Dehghan; N. Ladommatos; T. J. Brennan

1997-01-01

198

Simulation of a Hydraulic Pump Control Valve  

NASA Technical Reports Server (NTRS)

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.

Molen, G. Vander; Akers, A.

1987-01-01

199

Mitral valve operations at a high-volume pediatric heart center: Evolving techniques and improved survival with mitral valve repair versus replacement  

PubMed Central

Mitral valve disease is quite variable and can occur as an isolated defect or in association with other complex left sided lesions. These lesions are often best described with detailed pre-operative imaging studies to define the valve anatomy and to access associated left heart disease. Depending on the type of mitral valve disease, various surgical repair techniques have led to improved survival in the recent era. We describe lesion specific approach to mitral valve repair and results.

Baird, Christopher W; Myers, Patrick O; Marx, Gerald; del Nido, Pedro J

2012-01-01

200

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

PubMed

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 randomized crossover study comprising three 10-week periods was performed. In the first and third period, participants exercised at lower or higher intensity (33% or 66% of HR reserve) in random order, with a sedentary period in between. Training programmes were identical except for intensity, and were performed under supervision thrice for 1 h per week. The results show that in the three conditions, that is, at rest before exercise, during exercise and during recovery, we found endurance training at lower and higher intensity to reduce SBP significantly (P<0.05) and to a similar extent. Further, SBP during recovery was, on average, not lower than at rest before exercise, and chronic endurance training did not affect the response of SBP after an acute bout of exercise. The effect of training on HR at rest, during exercise and recovery was more pronounced (P<0.05) with higher intensity. Finally, endurance training had no significant effect on sympathovagal balance. In conclusion, in participants at higher age, both training programmes exert similar effects on SBP at rest, during exercise and during post-exercise recovery, whereas the effects on HR are more pronounced after higher intensity training. PMID:19554028

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

2010-03-01

201

A Simple Automated Valve  

NASA Astrophysics Data System (ADS)

We have developed a simple computer controlled valve based on the popular Nupro B-4HK bellows valve. The valve is controlled by a stepping motor (Donovan Micro-Tek Inc.) using a Motorola MC3479 driver. TTL level input signals to the driver actuate the motor. With this stepping motor/driver combination it is possible to independently set the CW and CCW torque of the motor, something needed to avoid having the valve stick in the closed position. In order to get reproducible performance in setting a leak rate through the valve it was necessary to replace the supplied threaded handle used to open and close the valve with a fixed housing through which a threaded rod passes that operates the valve. The rod is moved in or out by rotating with the stepping motor. Performance data on the flow rate through the valve as a function of the opening of the valve will be presented. Three of these valves are in use in the gas handling system for an automated adsorption isotherm machine. They have each been cycled open/close over 1000 times with no difficulties.

Rollefson, R. J.; Ellis, F. M.

2001-03-01

202

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

PubMed

We present a low power, on demand Parylene MEMS electrothermal valve. A novel Omega-shaped thermal resistive element requires low power (approximately mW) and enables rapid valve opening (approximately ms). Using both finite element analysis and valve opening experiments, a robust resistive element design for improved valve opening performance in water was obtained. In addition, a thermistor, as an inrush current limiter, was added into the valve circuit to provide variable current ramping. Wireless activation of the valve using RF inductive power transfer was demonstrated. PMID:20024057

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

2010-01-01

203

New structural details of dermal lymphatic valves and its functional interpretation.  

PubMed

Dermal lymphatics (rat and human) were studied electronmicroscopically and changes within the lymphatic wall including neoformation of intralymphatic valves were followed by serial sections. Two new forms of intralymphatic valves were observed-unicellular valve or single endothelial cell extension deep into the lymphatic lumen and bunch valve, or a connective tissue core with numerous tip-cells at its cuspidal edge. These structures functioned as "flap" or "helper" valves and like inlet (intramural) valves, they were variable structures appearing and disappearing with changes in the local interstitial environment. Lymphatic capillaries probably act as microscopic pistons to pump and suction lymph fluid in a centripetal direction. PMID:6471917

Daroczy, J

1984-06-01

204

Automatic rotary valve actuator  

SciTech Connect

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.

Cook, W.E.

1985-03-28

205

Pneumatic Directional Control Valves  

NSDL National Science Digital Library

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.

Bartelt, Terry L.; Tomlin, Bonnie

2008-11-24

206

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

PubMed

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. PMID:4037910

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

1985-09-01

207

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

PubMed Central

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.

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

1985-01-01

208

Recently patented transcatheter aortic valves in clinical trials.  

PubMed

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

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

2013-12-01

209

Tubing drain valve  

SciTech Connect

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.

Soderberg, P.B.

1987-02-24

210

Triple Starr Valve Replacement  

PubMed Central

Of nine patients who have had triple valve replacements for organic rheumatic triple valve disease two died in the postoperative period from inadequate myocardial reserve, and a third died four months later from cerebral embolism originating from clot on the left atrial wall. The remainder are well and, except for one, leading normal lives. Though cardiac transplantation has been recommended and used successfully for triple valve disease by Cooley, it is suggested that the long-term outlook today of triple valve replacement is likely to be better than that of transplantation. ImagesFig. 1Fig. 2Fig. 3

Braimbridge, M. V.; Clement, A. J.; Brown, A. Hedley; Sabar, E.; Mendel, D.

1969-01-01

211

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

212

Preliminary characterization of active MEMS valves.  

SciTech Connect

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.

Barnard, Casey Anderson

2010-08-01

213

Inter-observer variability in diagnosing radiological features of aneurysmal subarachnoid hemorrhage; a preliminary single centre study comparing observers from different specialties and levels of training  

PubMed Central

Background: A noncontrast computed tomography (CT) scan remains the initial radiological investigation of choice for a patient with suspected aneurysmal subarachnoid hemorrhage (aSAH). This initial scan may be used to derive key information about the underlying aneurysm which may aid in further management. The interpretation, however, is subject to the skill and experience of the interpreting individual. The authors here evaluate the interpretation of such CT scans by different individuals at different levels of training, and in two different specialties (Radiology and Neurosurgery). Methods: Initial nonontrast CT scan of 35 patients with aSAH was evaluated independently by four different observers. The observers selected for the study included two from Radiology and two from Neurosurgery at different levels of training; a resident currently in mid training and a resident who had recently graduated from training of each specialty. Measured variables included interpreter's suspicion of presence of subarachnoid blood, side of the subarachnoid hemorrhage, location of the aneurysm, the aneurysm's proximity to vessel bifurcation, number of aneurysm(s), contour of aneurysm(s), presence of intraventricular hemorrhage (IVH), intracerebral hemorrhage (ICH), infarction, hydrocephalus and midline shift. To determine the inter-observer variability (IOV), weighted kappa values were calculated. Results: There was moderate agreement on most of the CT scan findings among all observers. Substantial agreement was found amongst all observers for hydrocephalus, IVH, and ICH. Lowest agreement rates were seen in the location of aneurysm being supra or infra tentorial. There were, however, some noteworthy exceptions. There was substantial to almost perfect agreement between the radiology graduate and radiology resident on most CT findings. The lowest agreement was found between the neurosurgery graduate and the radiology graduate. Conclusion: Our study suggests that although agreements were seen in the interpretation of some of the radiological features of aSAH, there is still considerable IOV in the interpretation of most features among physicians belonging to different levels of training and different specialties. Whether these might affect management or outcome is unclear.

Siddiqui, Usman T.; Khan, Anjum F.; Shamim, Muhammad Shahzad; Hamid, Rana Shoaib; Alam, Muhammad Mehboob; Emaduddin, Muhammad

2014-01-01

214

Transseptal Mitral Valve Replacement after Transcatheter Aortic Valve Implantation  

PubMed Central

We report a case of mitral valve replacement in a patient who had previously undergone transcatheter aortic valve implantation. A transseptal approach was used to avoid displacing the aortic prosthesis. Because of the small mitral annulus, a bioprosthetic aortic valve was used in reverse position for mitral valve replacement. The procedure did not interfere with the existing prosthesis, and a follow-up echocardiogram showed that both prosthetic valves were functioning well. To the best of our knowledge, this is the first report of mitral valve replacement in a patient who had a preceding transcatheter aortic valve implantation. We believe that the transseptal approach is promising for mitral valve replacement in such patients. Moreover, using a bioprosthetic aortic valve in reverse position is an option for mitral valve replacement when the mitral annulus is too small for placement of a standard bioprosthetic mitral valve.

Flannery, Laura D.; Lowery, Robert C.; Sun, Xiumei; Satler, Lowell; Corso, Paul; Pichard, Augusto; Wang, Zuyue

2012-01-01

215

Non-plugging injection valve  

DOEpatents

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

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

1985-01-01

216

Prosthetic heart valves: a review.  

PubMed

There are a number of difficulties inherent in the analysis of such a large and diverse quantity of data. In a substantial number of clinical trials, there is no significant effort made to evaluate prosthetic performance as a function of preoperative cardiac anatomy. Hemodynamics have not been systematically studied in relation to preexisting left ventricular size, shape, or configuration, mitral annular orientation, or left atrial size. Postoperative anticoagulation protocols vary from one institution to another and occasionally within study groups themselves. Less tangible variables such as alteration in surgical technique over time and differential familiarity of cardiovascular surgeons with the prostheses employed are chronic problems in any study of this sort. Perhaps the greatest variable in evaluating the postoperative performance of valvular prostheses over the past 20 yr is the radical improvement in techniques of intraoperative myocardial preservation. Notwithstanding, comparisons are possible within the confines of certain criteria. The caged ball value remains in use after 20 years of clinical experience. It has sustained the greatest number of modifications, probably because it has been the most extensively studied. Hemodynamics are adequate although its centrally obstructed design is responsible for increased turbulence, hemolysis, and neointimal proliferation, particularly in the aortic position. The device has been shown to be durable with virtually no reports of ball variance since the alteration of the silicone curing procedure in 1965. Thromboembolic rates are acceptable in the anticoagulated patient while prosthetic thrombosis is not a grave threat in the non-close clearance device. Incidence of endocarditis is not particularly different from that associated with all nonbioprosthetic valves, although there is a much greater published volume of clinical experience concerning recognition and treatment of late prosthetic valve endocarditis in patients with caged ball valves than there is for any other replacement device. Perhaps the most serious disadvantage to caged ball design is its size. Its large spatial requirements have led to anatomic complications in patients with small aortic roots, isolated mitral stenosis, left ventricular hypertrophy, and double valve replacement, among others. Nevertheless, this is still the valve of choice in some centers.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6359270

McClung, J A; Stein, J H; Ambrose, J A; Herman, M V; Reed, G E

1983-01-01

217

Valve for abrasive material  

DOEpatents

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.

Gardner, Harold S. (Turtle Creek, PA) [Turtle Creek, PA

1982-01-01

218

Linear motion valve  

NASA Technical Reports Server (NTRS)

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

Chandler, J. A. (inventor)

1985-01-01

219

Air diverter valve  

Microsoft Academic Search

An air diverter valve is described for use with an internal combustion engine having an emission control system including an exhaust system, an air pump, and a passage connecting the pump to the exhaust system for secondary air flow. The air diverter valve consists of a housing forming a pump discharge pressure chamber having an inlet port and a discharge

D. J. Pozniak; R. N. Siewert

1974-01-01

220

Simple, Internally Adjustable Valve  

NASA Technical Reports Server (NTRS)

Valve containing simple in-line, adjustable, flow-control orifice made from ordinary plumbing fitting and two allen setscrews. Construction of valve requires only simple drilling, tapping, and grinding. Orifice installed in existing fitting, avoiding changes in rest of plumbing.

Burley, Richard K.

1990-01-01

221

Low Friction Servo Valve.  

National Technical Information Service (NTIS)

The low friction servo valve has a housing which contains therein an input shaft, a pair of slidably mounted valve spools, and an actuator. Mechanical input is received by the input shaft in order to provide rotational displacement thereof. This displacem...

R. F. Richter

1979-01-01

222

Servo Valve Driver.  

National Technical Information Service (NTIS)

The magnetic control circuit and transistor driver is for a hydraulic transfer valve of the type used in guided missile control systems. A binary control circuit is provided for such a valve in which control is accomplished through regulation of the satur...

R. A. Freiberg

1964-01-01

223

Transcatheter Valve-in-Valve Implantation for Early Prosthetic Valve Degeneration in Aortic and Mitral Positions.  

PubMed

Recently, transcatheter valve-in-valve implantation has emerged as a new alternative to surgical reoperation for degenerated bioprosthetic valves, either in the aortic or mitral position. The early experience and outcome of this strategy appears promising in highly selected patient groups. Here we report a case of early structural valve degeneration in the aortic and mitral position in a patient with chronic hemodialysis successfully treated with transthoracic transcatheter valve-in-valve implantation. PMID:24996712

Yamane, Kentaro; Nazif, Tamim M; Khalique, Omar; Hahn, Rebecca T; Leon, Martin B; Kodali, Susheel K; Williams, Mathew R; George, Isaac

2014-07-01

224

Posterior urethral valves.  

PubMed

Posterior urethral valves represent the most common post-vesical obstructive malformation. They affect the male gender and appear as intraluminal folds located immediately proximal to the verumontanum. One of the most credited pathogenetic theories considers them an anomalous insertion of mesonephric duct into the cloaca or an incomplete involution of plicae colliculi. At present, the diagnosis of posterior urethral valves is prenatal and the pattern is characterized by detrusor hypertrophy and more or less marked hydroureteronephrosis. Urinary tract disorders that accompany posterior urethral valves include moderate hydroureteronephrosis to severe functional impairment of the entire urinary tract with consequent renal failure. Treatment of posterior urethral valves consists in their resection. At present, with miniaturized endoscopes, valve fulguration is feasible also in newborn infants. In low-weight patients or in case of poor general condition, temporary external urinary bypass (e.g. cystostomy) is feasible. PMID:12696266

Manzoni, Carlo; Valentini, Anna Lia

2002-01-01

225

Valve disease in pregnancy.  

PubMed

Maternal cardiac disease is a major cause of non-obstetric morbidity and accounts for 10-25% of maternal mortality. Valvular heart disease may result from congenital abnormalities or acquired lesions, some of which may involve more than one valve. Maternal and fetal risks in pregnant patients with valve disease vary according to the type and severity of the valve lesion along with resulting abnormalities of functional capacity, left ventricular function, and pulmonary artery pressure. Certain high-risk conditions are considered contraindications to pregnancy, while others may be successfully managed with observation, medications, and, in refractory cases, surgical intervention. Communication between the patient?s obstetrician, maternal-fetal medicine specialist, obstetrical anesthesiologist, and cardiologist is critical in managing a pregnancy with underlying maternal cardiac disease. The management of the various types of valve diseases in pregnancy will be reviewed here, along with a discussion of related complications including mechanical prosthetic valves and infective endocarditis. PMID:25037517

Pessel, Cara; Bonanno, Clarissa

2014-08-01

226

Anticoagulation for Prosthetic Valves  

PubMed Central

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

Aranki, Sary F.

2013-01-01

227

Surgery of prosthetic valve thrombosis.  

PubMed

From January 1978 to August 1983, 41 prosthetic valve thromboses in 34 patients were operated upon in our service. They comprised 15 aortic, 25 mitral and one tricuspid valve thromboses. Seven patients had massive thrombus with dysfunction of the prosthesis; others had small and disseminated thrombi on their prosthesis (34 patients). In the aortic position, valve thrombosis occurred on 10 ball valves and 5 pivoting disc valves. In the mitral position, they occurred on 17 ball valves, 7 pivoting disc valves and one bioprosthesis. In 2 cases, aortic valve thrombectomy was successfully done. Others had valve replacement. Hospital mortality was high: 13 deaths. Survivors are free of recurrent valve thrombosis. One had a minor peripheral embolus. Prosthetic valve thrombosis is a serious condition. There are special problems related to diagnosis and treatment of these patients which we discuss, according to our experience of more than 4000 valvular replacements. PMID:6519100

Pavie, A; Bors, V; Baud, F; Gandjbakhch, I; Cabrol, C

1984-10-01

228

Central flow tilting disc valve for aortic valve replacement  

Microsoft Academic Search

A new central flow tilting disc valve has been introduced. The clinical experience from the first 50 patients treated with aortic valve replacement and followed up for 12 months is reported. The results obtained are so encouraging that the tilting disc valve is at present preferred for all aortic valve replacements in this institution.

Viking Olov Björk

1970-01-01

229

Leishmaniasis Direct Agglutination Test: Using Pictorials as Training Materials to Reduce Inter-Reader Variability and Improve Accuracy  

PubMed Central

Background The Direct Agglutination Test (DAT) has a high diagnostic accuracy and remains, in some geographical areas, part of the diagnostic algorithm for Visceral Leishmaniasis (VL). However, subjective interpretation of results introduces potential for inter-reader variation. We report an assessment of inter-laboratory agreement and propose a pictorial-based approach to standardize reading of the DAT. Methodology In preparation for a comparative evaluation of immunochromatographic diagnostics for VL, a proficiency panel of 15 well-characterized sera, DAT-antigen from a single batch and common protocol was sent to nine laboratories in Latin-America, East-Africa and Asia. Agreement (i.e., equal titre or within 1 titer) with the reading by the reference laboratory was computed. Due to significant inter-laboratory disagreement on-site refresher training was provided to all technicians performing DAT. Photos of training plates were made, and end-titres agreed upon by experienced users of DAT within the Visceral-Leishmaniasis Laboratory-Network (VL-LN). Results Pre-training, concordance in DAT results with reference laboratories was only 50%, although agreement on negative sera was high (94%). After refresher training concordance increased to 84%; agreement on negative controls increased to 98%. Variance in readings significantly decreased after training from 3.3 titres to an average of 1.0 titre (two-sample Wilcoxon rank-sum (Mann-Whitney) test (z?=??3,624 and p?=?0.0003)). Conclusion The most probable explanation for disagreement was subjective endpoint reading. Using pictorials as training materials may be a useful tool to reduce disparity in results and promote more standardized reading of DAT, without compromising diagnostic sensitivity.

Adams, Emily R.; Jacquet, Diane; Schoone, Gerard; Gidwani, Kamlesh; Boelaert, Marleen; Cunningham, Jane

2012-01-01

230

Assessing Technical Training Needs.  

ERIC Educational Resources Information Center

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)

Schwaller, Anthony E.; Slipy, Dave

1985-01-01

231

Pressure regulating valve controller  

SciTech Connect

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.

Goodman, R.B.

1988-04-05

232

Dual hydraulic safety valve  

SciTech Connect

This patent describes a subsurface well safety valve for controlling the fluid flow through a well conduit and including a housing having a bore and a valve closure member moving between open and closed positions for controlling the fluid flow through the bore, a tubular member telescopically moving in the housing for controlling the movement of the valve closure member. The improvement in fluid actuating means for actuating the valve closure member comprising, a first piston and cylinder assembly in the housing adapted to be connected to a hydraulic control line, the first assembly connected to the tubular member, a second piston and cylinder assembly in the housing adapted to be connected to a hydraulic control line, the second assembly disconnected from the tubular member, and means for disconnecting the first assembly from the tubular member and connecting the second assembly to the tubular member. The method of operating a subsurface well safety valve for controlling the fluid flow through a well conduit in which the valve includes a housing having a bore and a valve closure member moving between open and closed positions for controlling the fluid flow through the bore.

Leismer, D.D.; Blizzard, W.A. Jr.

1989-06-13

233

Aortic valve replacement in the elderly: bioprosthesis or mechanical valve?  

Microsoft Academic Search

Background. With increased life expectancy, valve operations are more and more common in elderly patients. The choice of valve substitute—mechanical valve or bioprosthesis—remains debated.Methods. Two groups of patients of the same age (69, 70, and 71 years) with isolated aortic valve replacement (mechanical 240, bioprostheses 289) were compared for mortality, morbidity, and valve-related complications.Results. No significant difference was found in

Yves Logeais; Thierry Langanay; Hervé Corbineau; Régine Roussin; Claude Rioux; Alain Leguerrier

1998-01-01

234

Actuator-Valve Interface Optimization.  

National Technical Information Service (NTIS)

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 t...

O. L. Burchett R. L. Jones

1986-01-01

235

Cavitation Inception in Spool Valves  

Microsoft Academic Search

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

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

1981-01-01

236

Face-Sealing Butterfly Valve  

NASA Technical Reports Server (NTRS)

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.

Tervo, John N.

1992-01-01

237

High Temperature Ultrahigh Vacuum Valves.  

National Technical Information Service (NTIS)

All-metal valves heatable up to 300 to 400 C in closed and open position were developed for handling aggressive gases such as UF6 in high vacuum technology. Sealing aspects of valves with large nominal width, such as transfer valve NW 150 and corner valve...

W. Baechler G. Jokisch H. P. Kabelitz K. Teutenberg

1976-01-01

238

Long life valve design concepts  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

239

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

ERIC Educational Resources Information Center

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

Chochard, Yves; Davoine, Eric

2011-01-01

240

Vibrations due to a test train at variable speeds in a deep bored tunnel embedded in London clay  

Microsoft Academic Search

This paper reports on the results of in situ vibration measur ements that have been performed within the frame of the CONVURT project at a site in Regent's Park on t he Bakerloo line of London Under- ground during 35 passages of a test train at a speed between 20 and 50 km\\/h. Vibration measurements have been performed on the

G. Degrande; P. Chatterjee; R. Klein; W. Van de Velde

241

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

ERIC Educational Resources Information Center

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…

McBride, Rebecca G.

2010-01-01

242

Pressure model of a four-way spool valve for simulating electrohydraulic control systems  

NASA Technical Reports Server (NTRS)

An equation that relates the pressure flow characteristics of hydraulic spool valves was developed. The dependent variable is valve output pressure, and the independent variables are spool position and flow. This causal form of equation is preferred in applications that simulate the effects of hydraulic line dynamics. Results from this equation are compared with those from the conventional valve equation, whose dependent variable is flow. A computer program of the valve equations includes spool stops, leakage spool clearances, and dead-zone characteristics of overlap spools.

Gebben, V. D.

1976-01-01

243

Improve safety with pilot operated relief valves  

SciTech Connect

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

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

1996-10-01

244

Mesofluidic two stage digital valve  

DOEpatents

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.

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

2013-12-31

245

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

PubMed

Transcatheter aortic valve implantation, as well as interventional mitral valve repair, offer reasonable therapeutic options for high-risk surgical patients. We report a rare case of early post-interventional aortic valve prosthesis migration to the left ventricular outflow tract, with paravalvular leakage and causing severe mitral valve regurgitation. Initial successful interventional mitral valve repair using a clipped edge-to-edge technique revealed, in a subsequent procedure, the recurrence of mitral valve regurgitation leading to progressive heart failure and necessitating subsequent surgical aortic and mitral valve replacement. PMID:23864579

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

2013-11-01

246

Heart valve surgery  

MedlinePLUS

... Methods include: Endoscopy Percutaneous surgery (through the skin) Robot-assisted surgery The surgeon may be able to ... to your doctor before having any type of medical procedure. The clicking of mechanical heart valves may ...

247

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.

2009-09-04

248

Mitral Valve Prolapse.  

ERIC Educational Resources Information Center

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

Bergy, Gordon G.

1980-01-01

249

Valve for gas centrifuges  

DOEpatents

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.

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

1984-01-01

250

Liquid blocking check valve  

DOEpatents

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

Merrill, John T. (Pleasant Hill, CA)

1984-01-01

251

AcidBase Variables During Incremental Exercise in Sprint-Trained Horses Fed a High-Fat Diet  

Microsoft Academic Search

Seven Arabian horses performed a standard incremental exercise test on a high-speed treadmill at 6% slope then were randomly assigned to two diets, a control diet of ground hay and concen- trates and a similar diet with 10% added fat (by weight). Horses were sprint-trained 4 dwk, and two additional exercise tests were performed at 5-wk intervals. Heart rates and

L. E. Taylor; P. L. Ferrante; D. S. Kronfeld; T. N. Meacham

252

Valve malfunction detection apparatus  

NASA Technical Reports Server (NTRS)

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.

Burley, Richard K. (inventor)

1993-01-01

253

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

Microsoft Academic Search

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

M Karpenko; N Sepehri

2002-01-01

254

BP neural network-based on fault diagnosis of hydraulic servo-valves  

Microsoft Academic Search

This paper presents a new approach for fault diagnosis of hydraulic servo-valves with the BP neural network based on genetic algorithm. The paper uses a known set of faults as the output to the valve-behavior model. An appropriate neural network is established to be the best solution to the problem. Adoption of this approach brings about advantages of shortening training

Hao Huang; Kui-Sheng Chen; Liang-Cai Zeng

2005-01-01

255

Ball valves solve turbine drain valve problem  

Microsoft Academic Search

Alabama Power's E.C. Gaston generating plant, a 1904-MW facility located 40 miles south of Birmingham, consists of four 250-MW units, one 884-MW unit, and a 20-MW combustion turbine. Over the years the utility has experienced recurring failure of turbine drain valves on Gaston Unit 5. Unit 5 uses a Combustion Engineering supercritical steam generator rated at 6,351,470 lb\\/hr main steam

McDaniel

1992-01-01

256

Mitral Valve Replacement with the SORIN Valve  

PubMed Central

From 1 March 1977 through 31 December 1987, 1,252 patients underwent mitral valve replacement with a SORIN-Biomedica 60° tilting-disc prosthesis at our institution. Hospital mortality was 7.3% (91 patients); prosthesis-related deaths, expressed as a percentage of hospital mortality, accounted for 12.1% of these early deaths. The 1,161 patients who survived hospitalization have been followed up for a total of 4,835 patient-years (range, 1 to 128 months; mean, 50.4 ± 27.3 months). Forty-three (3.7%) of these patients were lost to follow-up. The late mortality was 6.3% (1.5% ± 0.2% per patient-year), and the 10-year actuarial survival rate, excluding hospital mortality, was 89.1% ± 1.6%. The 10-year actuarial (and linearized) rates of freedom from valve-related complications were as follows: embolism, 94.4% ± 1.0% (0.93% ± 0.1% per patient-year); thrombosis of the prosthesis, 99.8% ± 0.1% (0.06% ± 0.03% per patient-year; hemorrhage, 93.7% ± 1.5% (0.95% ± 0.1% per patient-year); prosthetic valve endocarditis, 99.3% ± 0.3% (0.14% ± 0.05% per patient-year); reoperation, 90.6% ± 2.1% (1.1% ± 0.2% per patient-year); and overall complications, 76.6% ± 2.5% (2.9% ± 0.2% per patient-year). No structural deterioration was noted. These data not only confirm our previous reports concerning the reliability and durability of the SORIN prosthesis but also reveal a significant reduction, over the long term, in the overall incidence of valve-related complications. (Texas Heart Institute Journal 1991;18:16-23)

Pellegrini, Alessandro; Colombo, Tiziano; Quaini, Eugenio; Russo, Claudio; Vitali, Ettore; Donatelli, Francesco

1991-01-01

257

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

Code of Federal Regulations, 2010 CFR

...Inhalation and exhalation valves; check valves; minimum requirements. 84...Inhalation and exhalation valves; check valves; minimum requirements. (a...leakage of contaminated air. (c) Check valves designed and constructed to...

2010-10-01

258

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

Code of Federal Regulations, 2010 CFR

...Inhalation and exhalation valves; check valves; minimum requirements. 84...Inhalation and exhalation valves; check valves; minimum requirements. (a...leakage of contaminated air. (c) Check valves designed and constructed to...

2009-10-01

259

Actuator-valve interface optimization  

SciTech Connect

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)

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

1986-01-01

260

Transcatheter aortic valve implantation.  

PubMed

Transcatheter aortic valve implantation (TAVI) was introduced experimentally in 1989, based on a newly developed heart valve prosthesis - the stentvalve. The valve was invented by a Danish cardiologist named Henning Rud Andersen. The new valve was revolutionary. It was foldable and could be inserted via a catheter through an artery in the groin, without the need for heart lung machine. This allowed for a new valve implantation technique, much less invasive than conventional surgical aortic valve replacement (SAVR). Surgical aortic valve replacement is safe and improves symptoms along with survival. However, up to 1/3 of patients with aortic valve stenosis cannot complete the procedure due to frailty. The catheter technique was hoped to provide a new treatment option for these patients. The first human case was in 2002, but more widespread clinical use did not begin until 2006-2010. Today, in 2011, more than 40,000 valves have been implanted worldwide. Initially, because of the experimental character of the procedure, TAVI was reserved for patients who could not undergo SAVR due to high risk. The results in this group of patients were promising. The procedural safety was acceptable, and the patients experienced significant improvements in their symptoms. Three of the papers in this PhD-thesis are based on the outcome of TAVI at Skejby Hospital, in this high-risk population [I, II and IV]. Along with other international publications, they support TAVI as being superior to standard medical treatment, despite a high risk of prosthetic regurgitation. These results only apply to high-risk patients, who cannot undergo SAVR. The main purpose of this PhD study has been to investigate the quality of TAVI compared to SAVR, in order to define the indications for this new procedure. The article attached [V] describes a prospective clinical randomised controlled trial, between TAVI to SAVR in surgically amenable patients over 75 years of age with isolated aortic valve stenosis. The study was terminated prematurely, as patients undergoing TAVI showed a statistically non-significant trend towards more complications than SAVR patients. Although non-significant the study was closed for ethical reasons. At present, scientific evidence supports TAVI as being superior to standard medical treatment, in patients who cannot undergo SAVR due to high- predicted risk. However, in patients who are surgically amenable, current publications suggest that TAVI using presently available devices is not competitive to SAVR, with regards to procedural safety and outcome. PMID:23290293

Nielsen, Hans Henrik Møller

2012-12-01

261

Successful transcatheter valve-in-valve implantation in a small deteriorated aortic valve bioprosthesis.  

PubMed

Increased life expectancy and improvement in clinical outcome following surgery has led to an increasing number of elderly patients with a history of prior aortic valve replacement (AVR). As a consequence, a considerable number of patients may require reintervention due to a dysfunctional bioprosthesis with structural valve deterioration (SVD). Transcatheter aortic valve implantation (TAVI) has become an established surgical alternative in patients with aortic stenosis and severe comorbidities. For those patients requiring reoperation, the 'valve-in-valve' concept has been described. Here, the case is reported of a patient with a very small Sorin Soprano 18 bioprosthesis with SVD who underwent a reintervention with the transapical valve-in-valve technique. The implantation was uneventful, with no residual paravalvular leakage and a low mean transprosthetic gradient. The valve-in-valve procedure may represent a feasible alternative for redo AVR in patients with a very small, structurally deteriorated bioprosthesis. PMID:24151773

Bjursten, Henrik; Götberg, Matthias; Harnek, Jan; Nozohoor, Shahab

2013-05-01

262

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

ERIC Educational Resources Information Center

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

Romi, Shlomo; Leyser, Yona

2006-01-01

263

Exploring inclusion preservice training needs: a study of variables associated with attitudes and self?efficacy beliefs  

Microsoft Academic Search

The study examined attitudes towards inclusion and sense of efficacy of 1155 Israeli preservice teachers and variables related to these beliefs. Participants responded to an Options related to inclusion scale, and a Teacher efficacy scale. Findings revealed strong support for the principle of inclusion, yet also support for segregated special education placements. Several concerns regarding inclusion were expressed, which were

Shlomo Romi; Yona Leyser

2006-01-01

264

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

ERIC Educational Resources Information Center

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

Hatch, James Cordell

265

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

266

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

267

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

268

[Technologies for cardiac valve prostheses].  

PubMed

To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies. PMID:20715694

Nakano, Kiyoharu

2009-07-01

269

Check valves aging assessment  

SciTech Connect

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

Haynes, H.D.

1991-01-01

270

Valve tappet apparatus  

SciTech Connect

This patent describes a valve tappet apparatus for use with an internal combustion engine having a plurality of valve members and cam means for causing reciprocating movement of the valve members, the apparatus comprising: a first tappet body associated with one of the valve members and with the cam means, at least a portion of the first tappet body having a curved outer circumference; a second tappet body associated with another of the valve members and with the cam means, at least a portion of the second tappet body having a curved outer circumference; an elongated, rigid link bar having a first end and a second end; a first attachment means attaching the first end of the link bar to the fist tappet body, and a second attachment means attaching the second end of the link bar to the second tappet body, the second attachment means including a screw for extending through at least a portion of the second tappet body, the second attachment means including a nut member for attaching the second end of the link bar to the distal end of the screw of the second attachment means, the nut member having a face side for engaging the outer circumference of the second tappet body, the face surface of the nut member having a concaved portion for engaging a portion of the outer circumference of the second tappet body.

Gerchow, J.R.; Russell, D.K.

1989-03-07

271

Fast closing valve  

DOEpatents

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

Hanson, Clark L. (Livermore, CA) [Livermore, CA

1984-01-10

272

Transcatheter aortic valve replacement with CoreValve.  

PubMed

The treatment of aortic stenosis in high-risk surgical patients is now possible by transcatheter aortic valve replacement. The CoreValve is a new transcatheter valve with a unique design expanding its application in patients with aortic stenosis. The CoreValve is just completing clinical trial in the United States and not yet available for commercial use in the United States but is widely used in Europe. PMID:23931099

Matthews, Ray V; Shavelle, David M

2013-08-01

273

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

274

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

275

Sutureless aortic valve replacement using perceval s valve.  

PubMed

Surgical aortic valve replacement is the treatment of choice in patients with severe symptomatic aortic valve stenosis because it provides excellent early and long-term clinical outcomes in terms of hemodynamics, valve durability, and freedom from valve-related complications. In recent years, the number of high-risk patients being referred for surgical aortic valve replacement has increased. A considerable proportion of these patients are deemed operable despite the high risk. In order to modify the risk predominantly associated with duration of cardiopulmonary bypass and cross clamp time sutureless aortic valve technology has been developed. Sutureless aortic bioprosthetic valves, introduced in clinical practice in 2009, contrary to the conventional surgical technique for implantation (interrupted or continuous sutures, after thorough annular decalcification) are not hand sewn. This technological modification reduces the implantation time with potential translation into improved outcomes for high-risk patients undergoing surgical aortic valve replacement. Currently, three sutureless bioprostheses are available and amongst these the largest published experience is available for the patented and CE marked truly sutureless PERCEVAL S valve (Sorin Group, Saluggia, Italy). This article provides an overview of the published literature for Perceval S valve with an attempt to better define the role of sutureless aortic valve replacement in the treatment of critical aortic valve stenosis. PMID:23713960

Raja, Shahzad G

2013-08-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

277

Locking apparatus for gate valves  

DOEpatents

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

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

1988-01-01

278

Bovine colostrum supplementation's lack of effect on immune variables during short-term intense exercise in well-trained athletes.  

PubMed

The purpose of this study was to investigate the potential of bovine colostrum to attenuate postexercise decline in immune function. The authors evaluated the time course of a number of immune variables after short-term intense exercise in 9 male athletes after 10 d of supplementation with either colostrum or skim-milk powder. To increase the stress on the immune system subjects performed a glycogen-depletion trial the evening before the endurance trial (90 min at 50% Wmax). Blood samples were taken before the glycogen-depletion trial, before and after the endurance trial, and the next morning, ~22 hr after cessation of the exercise. Plasma cortisol levels increased over time, reaching the highest level directly after exercise, and were still elevated ~22 hr after exercise compared with baseline values (p < .001). Neutrophil cell count was increased after exercise and dropped below starting values 22 hr after exercise (time effect p < .001). Circulating immunoglobulins did not change over time. A significant time effect was seen for interleukin (IL)-6, IL-10, IL-1-receptor agonist, and C-reactive protein, with levels being higher directly after exercise (p < .05). Other cytokines (interferon-?, IL-1a, IL-8, tumor necrosis factor-a) did not show a time effect. No differences were seen between colostrum and skim-milk powder in any of the investigated variables. Our results are consistent with the hypothesis that intense exercise affects several variables of the immune system. Colostrum did not alter any of the postexercise immune variables compared with skim-milk powder, suggesting no role for bovine colostrum supplementation in preventing postexercise immune suppression after short-term intense exercise. PMID:21558575

Carol, Arnoud; Witkamp, Renger F; Wichers, Harry J; Mensink, Marco

2011-04-01

279

Mechanical properties of myxomatous mitral valves  

Microsoft Academic Search

Objective: We sought to characterize the mechanical properties of normal and myxomatous mitral valve tissues. Methods: We tested 113 mitral valve sections from patients undergoing mitral valve repair or replacement for myxomatous mitral valve prolapse and sections from 33 normal valves obtained at autopsy. Results: Myxomatous mitral valve leaflets were more extensible than normal leaflets when tested parallel to the

J. Edward Barber; F. Kurtis Kasper; Norman B. Ratliff; Delos M. Cosgrove; Brian P. Griffin; Ivan Vesely

2001-01-01

280

Hydrogen gas relief valve  

DOEpatents

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

Whittlesey, Curtis C. (Birmingham, MI)

1985-01-01

281

Magnetostrictive valve assembly  

NASA Technical Reports Server (NTRS)

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

Richard, James A. (Inventor)

2008-01-01

282

Valve-spring surge  

NASA Technical Reports Server (NTRS)

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

Marti, Willy

1937-01-01

283

Valve-spring Surge  

NASA Technical Reports Server (NTRS)

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

Marti, Willy

1937-01-01

284

Percutaneous mitral valve repair.  

PubMed

Nonsurgical treatment of clinically important mitral regurgitation (MR) has evolved tremendously over the past decade. Recent studies of percutaneous mitral valve repair procedures have shown that less invasive procedures are safe and can be effective in selected patients. MitraClip has been studied most extensively. The MitraClip is attached to the middle scallop of the mitral leaflets by a transseptal-transvascular approach. The device approximates the leaflets in an edge-to-edge percutaneous repair technique that diminishes MR, improves functional status, and improves left ventricular remodeling. The subgroup that has the most benefit includes patients with older age, poorer left ventricular function, and functional MR and is considered high risk for surgical valve replacement. Other novel percutaneous mitral valve therapies under investigation include indirect and direct annuloplasty, and ventricular remodeling devices. PMID:24281977

Young, Amelia; Feldman, Ted

2014-01-01

285

Flow characteristics and performance evaluation of butterfly valves using numerical analysis  

NASA Astrophysics Data System (ADS)

The industrial butterfly valves have been applied to various fields that transport fluid in volume, especially water supply and drainage pipeline for flow control. The butterfly valves in various shapes are manufactured, but a fitting performance comparison is not made up. For this reason, we carried out numerical analysis of some kind of butterfly valves for water supply and drainage pipeline using commercial CFD code FLUENT, and made a comparative study of these results. Also, the flow coefficient, the loss coefficient, and pressure distribution of valves according to valve opening rate were compared each other and the influence of these design variables on valve performance were checked over. Through flow around the valve disk, such as pressure distribution, flow pattern, velocity vectors, and form of vortex, we grasped flow characteristics.

Jeon, S. Y.; Yoon, J. Y.; Shin, M. S.

2010-08-01

286

Acoustic and ultrasonic signals as diagnostic tools for check valves  

SciTech Connect

A typical nuclear plant has between 60 and 115 safety-related check valves ranging from 2 to 30 in. The majority of these valves control water flow. Recent studies done by the Institute of Nuclear Power Operations (INPO), Electric Power Research Institute (EPRI) and the US Nuclear Regulatory Commission (NRC) found that many of these safety-related valves were not functioning properly. Typical problems found in these valves included disk flutter, backstop tapping, flow leakage, disk pin and hinge pin wear, or even missing disks. These findings led to INPO's Significant Operating Experience Report (SOER, 1986), and finally, NRC generic letter 8904, which requires that all safety-related check valves in a nuclear plant be regularly monitored. In response to this need, the industry has developed various diagnostic equipment to monitor and test check valves, using technologies ranging from acoustics and ultrasonics to magnetic - even radiography has been considered. Of these, systems that depend on a combination of acoustic and ultrasonic techniques are among the most promising for two reasons: these two technologies supplement each other, making diagnosis of the check valves much more certain than any single technology, and this approach can be made nonintrusive. The nonintrusive feature allows the check valves to be monitored and diagnosed without being disassembled or removed from the piping system. This paper shows that by carefully studying the acoustic and ultrasonic signatures acquired from a check value, either individually or in combination, an individual with the proper training and experience in acoustic and ultrasonic signature analyses can deduce the structural integrity of the check valve with good confidence. Most of the conclusions are derived from controlled experiments in the laboratory where the diagnosis can be verified. Other conclusions were based on test data obtained in the field.

Auyang, M.K. (B and W Nuclear Technologies, Lynchburg, VA (United States))

1993-05-01

287

Automatic monitoring of valve status  

SciTech Connect

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

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

1989-06-01

288

Tide gate valve  

SciTech Connect

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

Raftis, S. G.

1985-01-08

289

Pressure Relief Valve  

NASA Technical Reports Server (NTRS)

"Sputtering" is the process of applying film-like metal coatings onto a surface by bombarding the coating material with electrocharged ions. This causes the material to disintegrate and relocate on the substrate an atom layer at a time. The process allows a variety of coating materials to be deposited on various surfaces. Deposition Technology, Inc. (DTI) uses "sputtering" for window films, packaging materials, etc. Valves installed on two vacuum chambers which are part of DTI's system, were developed by Lewis Research Center and detailed in Tech Briefs. The valve protects the environment and frees the operator from monitoring the chamber venting.

1985-01-01

290

Heart rate recovery and heart rate variability are unchanged in patients with coronary artery disease following 12 weeks of high-intensity interval and moderate-intensity endurance exercise training.  

PubMed

Decreased heart rate variability and attenuated heart rate recovery following exercise are associated with an increased risk of mortality in cardiac patients. This study investigated the effects of 12 weeks of moderate-intensity endurance exercise (END) and a novel low-volume high-intensity interval exercise protocol (HIT) on measures of heart rate recovery and heart rate variability in patients with coronary artery disease (CAD). Fourteen males with CAD participated in 12 weeks of END or HIT training, each consisting of 2 supervised exercise sessions per week. END consisted of 30-50 min of continuous cycling at 60% peak power output (PPO). HIT involved ten 1-min intervals at 88% PPO separated by 1-min intervals at 10% PPO. Heart rate recovery at 1 min and 2 min was measured before and after training (pre- and post-training, respectively) using a submaximal exercise bout. Resting time and spectral and nonlinear domain measures of heart rate variability were calculated. Following 12 weeks of END and HIT, there was no change in heart rate recovery at 1 min (END, 40 ± 12 beats·min(-1) vs. 37 ± 19 beats·min(-1); HIT, 31 ± 8 beats·min(-1) vs. 35 ± 8 beats·min(-1); p ? 0.05 for pre- vs. post-training) or 2 min (END, 44 ± 18 beats·min(-1) vs. 43 ± 19 beats·min(-1); HIT, 42 ± 10 beats·min(-1) vs. 50 ± 6 beats·min(-1); p ? 0.05 for pre- vs. post-training). All heart rate variability indices were unchanged following END and HIT training. In conclusion, neither END nor HIT exercise programs elicited training-induced improvements in cardiac autonomic function in patients with CAD. The absence of improvements with training may be attributed to the optimal medical management and normative pretraining state of our sample. PMID:23724882

Currie, Katharine D; Rosen, Lee M; Millar, Philip J; McKelvie, Robert S; Macdonald, Maureen J

2013-06-01

291

Lightweight Valve Closes Duct Quickly  

NASA Technical Reports Server (NTRS)

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.

Fournier, Walter L.; Burgy, N. Frank

1991-01-01

292

Kelly mud saver valve sub  

Microsoft Academic Search

A mud saver valve is described for preventing drilling mud from escaping from a kelly when a drill string is broken below the kelly, the valve comprising: a tubular valve body having first and second ends, the first end being provided with means for attachment in fluid communicating relationship with the kelly, the second end being provided with means for

Reddoch

1986-01-01

293

Valve stem and packing assembly  

DOEpatents

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.

Wordin, J.J.

1991-09-03

294

Valve stem and packing assembly  

DOEpatents

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.

Wordin, John J. (Bingham County, ID)

1991-01-01

295

Living with Mitral Valve Prolapse  

MedlinePLUS

... from the NHLBI on Twitter. Living With Mitral Valve Prolapse Most people who have mitral valve prolapse (MVP) have no symptoms or related problems, ... them with medicine. Some people may need heart valve surgery to relieve their symptoms and prevent complications. ...

296

Pilot-booster control valve  

NASA Technical Reports Server (NTRS)

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.

Marley, D.

1970-01-01

297

Variable force solenoid pressure control for an automatic transmission  

SciTech Connect

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.

Lemieux, G.E.

1989-05-30

298

The effects of autogenic-feedback training on motion sickness severity and heart rate variability in astronauts  

NASA Technical Reports Server (NTRS)

Space motion sickness (SMS) affects 50 percent of all people during early days of spaceflight. This study describes the results of two Shuttle flight experiments in which autogenic-feedback training (AFT), a physiological conditioning method, was tested as a treatment for this disorder. Of the six who were designated as flight subjects (two women and four men), three were given treatment and three served as controls (i.e., no AFT). Treatment subjects were given 6 hours of preflight AFT. Preflight results showed that AFT produced a significant increase in tolerance to rotating chair motion sickness tests. Further, this increased tolerance was associated with changes in specific physiological responses and reports of reduced malaise. Flight results showed that two of the three control subjects experienced repeated vomiting on the first mission day, while one subject experienced only moderate malaise. Of the three treatment subjects, one experienced mild discomfort, one moderate discomfort, and one severe motion sickness. Only the three control subjects took medication for symptom suppression. Measures of cardiac function reflective of vagal control were shown to be affected especially strongly on the first day of space flight. AFT given for control of heart rate, respiration, and other autonomic activity influenced both the vagal control measures and SMS. These data suggest that AFT may be an effective treatment for space motion sickness; however, this cannot be demonstrated conclusively with the small number of subjects described.

Toscano, William B.; Cowings, Patricia S.

1994-01-01

299

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

PubMed

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

Hoffmann, Rainer; Möllmann, Helge; Lotfi, Shahram

2013-12-01

300

Valve for gas centrifuges  

DOEpatents

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.

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

1982-03-17

301

Torpedo Tube Slide Valve.  

National Technical Information Service (NTIS)

A torpedo tube and slide valve assembly includes a torpedo tube having a plurality of circumferentially spaced slots therein and an impulse tank surrounding the torpedo tube wherein the slots provide a flow path between the impulse tank and the interior o...

P. E. Moody

1994-01-01

302

Minimally Invasive Valve Operations  

Microsoft Academic Search

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

Delos M Cosgrove; Joseph F Sabik; José L Navia

1998-01-01

303

Vent Relief Valve Test  

NASA Technical Reports Server (NTRS)

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.

2008-01-01

304

Valve Repair or Replacement  

MedlinePLUS

... works harder than the right. They control the flow of oxygen-rich blood from the lungs to the rest ... valve repair or replacement surgeries. This will keep oxygen-rich blood flowing ... or blood-flow specialist operates the heart-lung machine. Before you ...

305

Model Heart Valves  

NSDL National Science Digital Library

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

Vu Bioengineering Ret Program

306

Tricuspid and Pulmonic Valve Disease  

Microsoft Academic Search

\\u000a In the adult, the tricuspid and pulmonic valves are in general less affected by disease states compared to left-sided cardiac\\u000a valves. While right-sided valves are essential in maintaining hemodynamic balance and in dictating long-term prognosis, valvular\\u000a disease is better tolerated compared to left-sided valves. With the common occurrence of trivial regurgitation in right-sided\\u000a valves in normal individuals, noninvasive determination of

Meeney Dhir; William A. Zoghbi

307

A child with Beckwith-Wiedemann syndrome and posterior urethral valves.  

PubMed

Beckwith-Wiedemann syndrome is a somatic overgrowth syndrome characterized by a variable incidence of congenital anomalies, including hemihypertrophy, omphalocele, macroglossia and renal malformations. We report a child with Beckwith-Wiedemann syndrome and posterior urethral valves. Urethral valve resection was successfully performed under general anesthesia after voiding cystourethrography. This is the first report of Beckwith-Wiedemann syndrome associated with posterior urethral valves. PMID:15844777

Buyukcelik, M; Satar, N; Dursun, H; Bayazit, Y; Bayazit, A K; Soran, M; Noyan, A; Anarat, A

2005-01-01

308

Sex-specific responses to self-paced, high-intensity interval training with variable recovery periods.  

PubMed

This study examined sex-specific responses during self-paced, high-intensity interval training (HIIT). Sixteen (8 men and 8 women) individuals completed a peak oxygen uptake test and 3 treadmill HIIT sessions on separate days. The HIIT sessions consisted of six 4-minute intervals performed at the highest self-selected intensity individuals felt they could maintain. Recovery between intervals was counterbalanced and consisted of 1-, 2-, or 4-minute recovery during each trial. Relative measures of intensity, including percentage of velocity at VO2peak (vVO2peak), %VO2peak, %HRmax, and blood lactate concentration ([La]), were observed during the trials. Perceived readiness was recorded immediately before and ratings of perceived exertion (RPE) were recorded at the end of each interval with session RPE recorded after each trial. Results revealed a significant effect of sex on %vVO2peak (p < 0.01) and %HRmax (p < 0.01). Data show that across trials, men self-select higher %vVO2peak (84.5 vs. 80.7%), whereas women produce higher %HRmax (96.9 vs. 92.1%) and %VO2peak (89.6 vs. 86.1%) with no difference in [La] or perceptual responses. These findings support the notion that women may demonstrate improved recovery during high-intensity exercise, as they will self-select intensities resulting in greater cardiovascular strain. Moreover, results confirm previous findings suggesting that a 2:1 work-to-rest ratio is optimal during HIIT for both men and women. PMID:23838976

Laurent, C Matthew; Vervaecke, Lauren S; Kutz, Matthew R; Green, J Matthew

2014-04-01

309

Miniature Latching Valve  

NASA Technical Reports Server (NTRS)

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.

Johnson, A. David; Benson, Glendon M.

2008-01-01

310

Multi-port valve assembly  

DOEpatents

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.

Guggenheim, S. Frederic (Teaneck, NJ)

1986-01-01

311

Micro-valve pump light valve display  

DOEpatents

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

Yeechun Lee.

1993-01-19

312

Micro-valve pump light valve display  

DOEpatents

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

Lee, Yee-Chun (Cabin John, MD)

1993-01-01

313

Delineation in thoracic oncology: a prospective study of the effect of training on contour variability and dosimetric consequences  

PubMed Central

Introduction As part of French residents' radiotherapy training, delineation workstations were available at a national teaching course. We report a prospective comparative study of a non small cell lung cancer (NSCLC) case delineated by 120 residents before and after a radioanatomy/radiotherapy lecture. Materials and methods The case of a patient with right upper lobe non small cell lung cancer (NSCLC) was provided for delineation to 32 groups of residents before and after a radiation therapy lecture about thoracic delineation. GTV, CTV and PTV was asked to each group. In a second step, the GTV, CTV and PTV were compared with those of 9 groups of senior physicians. Finally the consequences for treatment planning between each group before and after the course were explored. Results The expert's average GTV, CTV and PTV were 89.1 cm3, 242.3 cm3 and 293.9 cm3 respectively. For residents, those volumes were 103.4 cm3, 242.3 cm3 and 457.9 cm3 before teaching, compared to 99.5 cm3, 224.2 cm3 and 412.5 cm3 after teaching. The overlap (OV) and kappa (KI) indices before and after education were respectively 0.58 and 0.73. Compared to senior physicians, OV and KI indices were lower in the residents group (p = 0.039 and p = 0.043). An increased dose to the lung is noted for the residents' dosimetry compared to the experts' (V20: 23.2% versus 36.5%) due to the larger PTV delineated. No significant difference was observed for other organs at risk. Conclusion There were no significant differences for the delineation of the GTV and CTV before and after the course, although the differences tended to decrease after the course. The good initial quality of the contours could explain the lack of difference. V20 for lung was higher in the residents group compared to the experts group (23.2% vs 36.5%). No other treatment planning consequences were observed for other critical organs.

2011-01-01

314

Interrelationships between different loads in resisted sprints, half-squat 1 RM and kinematic variables in trained athletes.  

PubMed

Resisted sprint running is a common training method for improving sprint-specific strength. It is well-known that an athlete's time to complete a sled-towing sprint increases linearly with increasing sled load. However, to our knowledge, the relationship between the maximum load in sled-towing sprint and the sprint time is unknown, The main purpose of this research was to analyze the relationship between the maximum load in sled-towing sprint, half-squat maximal dynamic strength and the velocity in the acceleration phase in 20-m sprint. A second aim was to compare sprint performance when athletes ran under different conditions: un-resisted and towing sleds. Twenty-one participants (17.86 ± 2.27 years; 1.77 ± 0.06 m and 69.24 ± 7.20 kg) completed a one repetition maximum test (1 RM) from a half-squat position (159.68 ± 22.61 kg) and a series of sled-towing sprints with loads of 0, 5, 10, 15, 20, 25, 30% body mass (Bm) and the maximum resisted sprint load. No significant correlation (P<0.05) was found between half-squat 1 RM and the sprint time in different loaded conditions. Conversely, significant correlations (P<0.05) were found between maximum load in resisted sprint and sprint time (20-m sprint time, r=-0.71; 5% Bm, r=-0.73; 10% Bm, r=-0.53; 15% Bm, r=-0.55; 20% Bm, r=-0.65; 25% Bm, r=-0.44; 30% Bm, r=-0.63; MaxLoad, r= 0.93). The sprinting velocity significantly decreased by 4-22% with all load increases. Stride length (SL) also decreased (17%) significantly across all resisted conditions. In addition, there were significant differences in stride frequency (SF) with loads over 15% Bm. It could be concluded that the knowledge of the individual maximal load in resisted sprint and the effects on the sprinting kinematic with different loads, could be interesting to determinate the optimal load to improve the acceleration phase at sprint running. PMID:24444204

Martínez-Valencia, María Asunción; González-Ravé, José M; Santos-García, Daniel Juárez; Alcaraz Ramón, Pedro E; Navarro-Valdivielso, Fernando

2014-01-01

315

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

PubMed Central

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.

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

316

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

Code of Federal Regulations, 2013 CFR

...PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum...distortion. (b) Exhalation valves shall be: (1) Protected...leakage of contaminated air. (c) Check valves designed and...

2013-10-01

317

Fast acting multiple element valve  

DOEpatents

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

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

1991-01-01

318

Fast-acting valve and uses thereof  

DOEpatents

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.

Meyer, J.A.

1980-05-16

319

Fast-acting valve and uses thereof  

DOEpatents

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.

Meyer, James A. (Espanola, NM)

1982-01-01

320

Stemless ball valve  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

321

Percutaneous Pulmonary Valve Implantation  

PubMed Central

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

Lee, Hyoung-Doo

2012-01-01

322

Aspergillus prosthetic valve endocarditis.  

PubMed Central

The clinical, laboratory, and histopathological features of seven cases of Aspergillus fumigatus prosthetic valve endocarditis are presented. The exact nature of the lesion, a combination of infective fungal endocarditis and thrombosis on the prosthetic valve, is discussed and the difficulties in clinical diagnosis are emphasized. Helpful indications were sudden unexplained heart failure with the appearance of new murmurs, and emboli to large or medium-sized systemic arteries. Fever and anaemia were inconstant, and in no case was blood culture or precipitin investigation helpful. Spore contamination of operating theatre air was the likely source of infection, and measures taken to overcome this and other predisposing factors are discussed. Since medical diagnosis is usually late and the few reported cures in this condition have included replacement of the prosthesis, early surgical intervention combined with antifungal chemotherapy is advised. Images

Petheram, I S; Seal, R M

1976-01-01

323

Mycobacterial Prosthetic Valve Endocarditis  

Microsoft Academic Search

Prosthetic valve endocarditis (PVE) due to mycobacteria is a rare but frequently fatal complication that may occur early after\\u000a the surgical procedure, or even years later. Infection has been described with both mechanical and biologic valvular prosthesis.\\u000a The most commonly implicated mycobacterial species belong to the rapid-grower group (M. chelonei, M. fortuitum, and M. abscessus) of nontuberculous mycobacteria (NTM). The

Larry M. Bush; Anil Paturi; Fredy Chaparro-Rojas; Maria T. Perez

2010-01-01

324

Performance Characteristics of an Isothermal Freeze Valve  

SciTech Connect

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

Hailey, A.E.

2001-08-22

325

Valve operating system for internal combustion engine  

Microsoft Academic Search

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

M. Matsuura; M. Nakamori; M. Kuroki

1988-01-01

326

Noninvasive valve monitor using alternating electromagnetic field  

Microsoft Academic Search

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

D. M. Eissenberg; H. D. Haynes; D. A. Casada

1993-01-01

327

Supramolecular spin valves  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

328

Primary cardiac valve tumors.  

PubMed

To assess the prevalence, characteristics, and outcome of surgical treatment of primary cardiac valve tumors in a single center, we reviewed our experience in 6 women and 1 man, aged 49 to 76 years (mean, 64.7 years) who presented between 1999 and 2006. In one patient, the diagnosis of cardiac valve tumor was made incidentally on transesophageal echocardiography during aortocoronary bypass surgery. The others had clinical symptoms: angina or myocardial infarction in 3, congestive heart failure in 2, dyspnea and cerebrovascular ischemia in 1 patient each. Four of the 7 tumors were benign, and 3 were malignant. All patients survived the operation and recovered uneventfully. Midterm follow-up was available in all patients. Two patients with malignant tumors were considered unsuitable for adjuvant therapy by the oncologist; both died during follow-up from local tumor recurrence. All 5 survivors were categorized at the last follow-up as functional class I, with normal exercise tolerance. Excellent early and midterm surgical results can be obtained in patients with benign cardiac valve tumors, but the prognosis for those with a malignant tumor is poor. PMID:20519288

Georghiou, Georgios P; Vidne, Bernardo A; Sahar, Gideon; Sharoni, Erez; Fuks, Avi; Porat, Eyal

2010-06-01

329

Electromagnetic fuel injection valve  

SciTech Connect

An electromagnetic fuel injection valve is described comprising: (a) a housing made of a magnetic material; (b) a valve which opens and closes a fuel injection port that is hydraulically connected to the interior of the housing; (c) a moving core which drives the valve; (d) a fuel guide member which consists of a large diameter portion that is secured to the housing on the side opposite to the fuel injection port. A stationary core extends from the large diameter portion to protrude into the housing. A connection portion extends from the large diameter portion to protrude toward the outer side of the housing, and a penetration path extends from the protruding end of the stationary core to the protruding end of the connection portion; (e) an electromagnetic coil disposed in an annular space defined by the outer periphery of the stationary core and the inner periphery of the housing; (f) a tubular member which is disposed in the penetration path and which has openings at its both ends; and (g) sealing means which hydraulically seals the area between the outer periphery of the tubular member and the inner periphery of the penetration path at an end portion on the side of the fuel injection port of the tubular member.

Soma, M.; Atago, T.; Kido, T.

1986-12-02

330

Characterization of micromachined cantilever valves  

NASA Astrophysics Data System (ADS)

This paper reports the fabrication and simulation of micromachined cantilever valves. For quasi-static fluid - structural simulations, the FEM package ANSYS and the CFD package Flow3D are coupled with a control programme to yield the flow rate for the cantilever valve. The results are compared with micromachined cantilever valves. The fabrication of these valves can be subdivided into the generation of cantilevers and ducts via KOH etching and a final fusion bonding step to join them. For the release of the cantilever, toluene is used to avoid stiction while drying the chips. Agreement between measured and simulated flow rates is shown to be good and gives confidence in the use of this simulator for valve development. Dynamic simulations are established with an impact model of the cantilever sitting on top of the duct. This allows the prediction of the dynamic behaviour of cantilever valves.

Koch, M.; Evans, A. G. R.; Brunnschweiler, A.

1997-09-01

331

Update of transcatheter valve treatment  

PubMed Central

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.

Liu, Xian-bao; Wang, Jian-an

2013-01-01

332

Streamline coal slurry letdown valve  

DOEpatents

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.

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

1983-01-01

333

Semi-active compressor valve  

DOEpatents

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

Brun, Klaus (Helotes, TX); Gernentz, Ryan S. (San Antonio, TX)

2010-07-27

334

Streamline coal slurry letdown valve  

DOEpatents

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.

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

1983-11-08

335

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

Microsoft Academic Search

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,

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

2010-01-01

336

Innovative Stemless Valve Eliminates Emissions  

NASA Technical Reports Server (NTRS)

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

2008-01-01

337

49 CFR 192.145 - Valves.  

Code of Federal Regulations, 2013 CFR

... Valves. (a) Except for cast iron and plastic valves...conditions that exceed the applicable pressure-temperature ratings contained...requirements. (b) Each cast iron and plastic valve must...must have a maximum service pressure rating for temperatures...

2013-10-01

338

Ultrathin gate valve for high vacuum operation  

NASA Technical Reports Server (NTRS)

Thin, compact, high-vacuum gate valve used to join two vacuum systems together demonstrates multiple operation reliability. Valve measurements and non-protruding handle make valve usable in confined areas.

Ugiansky, R. J.

1971-01-01

339

Whitey Gauge and Root Valves (VPS)  

SciTech Connect

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.

MISKA, C.

2000-09-03

340

Low energy high pressure miniature screw valve  

DOEpatents

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

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

2006-12-12

341

49 CFR 195.420 - Valve maintenance.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 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...

2013-10-01

342

How Is Mitral Valve Prolapse Diagnosed?  

MedlinePLUS

... from the NHLBI on Twitter. How Is Mitral Valve Prolapse Diagnosed? Mitral valve prolapse (MVP) most often is detected during a ... listen to your heart with a stethoscope. Stretched valve flaps can make a clicking sound as they ...

343

Laboratory Testing of Prosthetic Heart Valves  

Microsoft Academic Search

A whole range of laboratory testing methods for prosthetic heart valves, such as steady flow testing, pulsatile flow testing, and fatigue testing, are presented. Comparative test results for various valve types are given and relative valve performance is discussed.

H Reul; M Giersiepen; E Knott

1987-01-01

344

Whitey Gauge and Root Valves (VPS)  

SciTech Connect

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.

MISKA, C.

2000-10-17

345

Perceval sutureless valve in freestyle root: new surgical valve-in-valve therapy.  

PubMed

Aortic root replacement with biological conduit (homograft, autograft, or xenograft) is a valuable tool, but biological valves are often prone to degeneration. Reoperations usually require root removal and repetition of the Bentall procedure to maintain the same orifice area. A less radical option is to limit replacement to the valve. In cases of calcified or very small roots, standard valve implantation cannot be performed, and bailout with a sutureless valve may be a particularly useful option. Here we have described a case of leaflet rupture in a calcified small Freestyle root (Medtronic Inc, Minneapolis, MN) in which we performed a valve-in-valve (V-in-V) procedure with a Perceval-S prosthesis (Sorin Group, Saluggia, Italy). PMID:24296228

Villa, Emmanuel; Messina, Antonio; Cirillo, Marco; Brunelli, Federico; Mhagna, Zean; Dalla Tomba, Margherita; Troise, Giovanni

2013-12-01

346

Surgery for fulminant prosthetic valve endocarditis after transapical transcatheter aortic valve-in-valve implantation.  

PubMed

We report the clinical course of a patient with a history of transapical aortic "valve-in-valve" transcatheter aortic valve implantation (TAVI), actually suffering from prosthetic valve endocarditis. The patient now underwent cardiac surgery as a salvage procedure. The procedure itself was uneventful, but the patient died several days postoperative due to persisting sepsis. The present case raises the question, how to deal with high-risk patients, once considered unsuitable for cardiac surgery in presence of prosthetic valve infection? Up to now, there exists only insufficient knowledge about incidence, clinical course, and effectiveness of treatment strategies for prosthetic valve endocarditis after TAVI. A review of the available literature is given. PMID:23344757

Wilbring, Manuel; Tugtekin, Sems Malte; Matschke, Klaus; Kappert, Utz

2014-02-01

347

Dual Valve Plate Two-Way Pressure Relief Valve.  

National Technical Information Service (NTIS)

This patent application discloses a two-way valve which includes dual valve plates to be positioned between first and second chambers having varying pressure therein, to relieve excess pressure in either chamber by permitting fluid flow from one chamber t...

R. J. Angeli

1993-01-01

348

High temperature ultrahigh vacuum valves. Final report  

Microsoft Academic Search

All-metal valves heatable up to 300 to 400°C in closed and open position were developed for handling aggressive gases such as UFâ in high vacuum technology. Sealing aspects of valves with large nominal width, such as transfer valve NW 150 and corner valve 150, and of valves with small nominal width, such as corner valves NW 6, 16, 35, and

W. Baechler; G. Jokisch; H. P. Kabelitz; K. Teutenberg

1976-01-01

349

Internal Acoustics of a Pintle Valve with Supercritical Helium Flow  

NASA Technical Reports Server (NTRS)

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

Fishbach, Sean R.; Davis, R. Benjamin

2010-01-01

350

Surge-damping vacuum valve  

DOEpatents

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

Bullock, Jack C. (Pleasanton, CA) [Pleasanton, CA; Kelly, Benjamin E. (Tracy, CA) [Tracy, CA

1980-01-01

351

Valve-"Health"-Monitoring System  

NASA Technical Reports Server (NTRS)

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.

Jensen, Scott L.; Drouant, George J.

2009-01-01

352

Gas\\/air mixing valve  

Microsoft Academic Search

This patent describes a gas\\/air mixing valve for connection to an air plenum to regulate the flow of combustion reactants to a burner. It comprises: a valve body defining a gas inlet for receiving a supply of combustion gas, a combustion air inlet orifice in communication with the air plenum for receiving a supply of air for combustion, a bleed

M. Nunes; M. P. Grimanis; J. R. Hurley; K. C. Shukla

1990-01-01

353

Mitral valve prolapse in children.  

PubMed

Mitral valve prolapse is extremely common in children. It is diagnosed by the presence of a nonejection click with or without an associated murmur. In isolated mitral valve prolapse, the prognosis is excellent, but regular office visits are necessary for cardiac status review and infective endocarditis prophylaxis. Patients with significant dysrhythmias represent a small subset with an unknown long-term prognosis. PMID:3825853

Greenwood, R D

1987-03-01

354

Method for Valve Height Measurements.  

National Technical Information Service (NTIS)

The research report concerns a method (developed earlier) to determine the position of a valve in a single action piston pump. The method uses a transducer with three magnetoresistive sensors (which detect magnetic field variations) and a valve with a bui...

F. Couweleers

1988-01-01

355

Air flow through poppet valves  

NASA Technical Reports Server (NTRS)

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.

Lewis, G W; Nutting, E M

1920-01-01

356

Automatic monitoring of valve status  

SciTech Connect

Authors note that acoustic emissions from valves and adjacent pipe, used to investigate the problem of valve leakage in power plants, cannot be separated so as to distinguish leakage processes from other causes of ultrasound emissions. They propose establishing the relationship between valve leaking and thermal gradient to allow detection of valve leakage by observing the piping system`s temperature profile. Authors note that their mathematical and experimental models of a typical power-plant piping section were found inconsistent, report known and suspected reasons for this, and suggest specific further studies to supply missing data. They also suggest designing modern power plants to accommodate a remotely controlled or autonomous vehicle which would carry a device for thermal-gradient leak detection to examine valves in situ.

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

1988-01-01

357

A Parylene MEMS Electrothermal Valve  

PubMed Central

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

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

2011-01-01

358

A Parylene MEMS Electrothermal Valve.  

PubMed

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

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

2009-12-01

359

FLUID MECHANICS OF ARTIFICIAL HEART VALVES  

PubMed Central

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

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

2009-01-01

360

[Surgical management of valve replacement in children].  

PubMed

From 1965 to 1990, 49 valve replacements were performed on 43 patients under the age of 15. Mitral valve replacements were performed on 21 patients, and re-replacements were done on 4 of them afterwards. In the first 9 mitral valve replacements before 1974, Starr-Edwards (S-E) ball valves were used. Five of these patients died in the hospital (early mortality rate was 56%). Since 1975, bioprosthetic valves were used in three cases, but all of these valves ceased to function due to primary tissue failure (PTF) within 3 years. Consequently, SJM valves are now used as a first choice. Ten aortic valve replacements were performed on 9 patients with the results of one early death, two late deaths, and one late re-operation. Tricuspid valve replacements were performed on 11 patients, 5 of whom utilized S-E ball valves. Three of the five patients died in the hospital. One patient was re-operated on, swapping the S-E ball valve for the SJM valve. SJM valves were used primarily in 2 patients, and bioprosthetic valves in 4. Two patients died, one with a SJM valve, and the other with a bioprosthetic valve. Two pulmonary valve replacements were performed, one employing a SJM valve, the other a bioprosthetic valve. Two adult patients with SJM valve in the right side of the heart had thrombotic complications, though the patients with bioprosthetic valves had none. Atrioventricular valve replacements were performed on 5 patients under the age of 3, but all of them died.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1942678

Kanazawa, H; Miyamura, H; Watanabe, H; Sugawara, M; Takahashi, Y; Shinonaga, M; Tatebe, S; Hayashi, J; Eguchi, S

1991-10-01

361

Two-dimensional spin diffusion in multiterminal lateral spin valves  

NASA Astrophysics Data System (ADS)

The effects of two-dimensional spin diffusion on spin extraction in lateral semiconductor spin valves have been investigated experimentally and theoretically. A ferromagnetic collector terminal of variable size is placed between the ferromagnetic electron spin injector and detector of a conventional lateral spin valve for spin extraction. It is observed that transverse spin diffusion beneath the collector terminal plays an important role along with the conventional longitudinal spin diffusion in describing the overall transport of spin carriers. Two-dimensional spin diffusion reduces the perturbation of the channel electrochemical potentials and improves spin extraction.

Saha, D.; Basu, D.; Holub, M.; Bhattacharya, P.

2008-01-01

362

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)

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.

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

2014-05-01

363

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

PubMed

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

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

364

Valve for controlling solids flow  

DOEpatents

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.

Feldman, David K. (Fairlawn, NJ)

1980-01-01

365

Vacuum valves for synchrotrons and storage rings  

Microsoft Academic Search

Key issues in selecting valves for synchrotrons, the sealing technologies used in the valves, and the types of valves commonly chosen are reviewed. Valves with metal static seals and viton plate seals are often used for isolating vacuum pumps or used on experimental lines when the environment permits them. Other elastomers can extend radiation resistance or bake limits. For radiation

John A. Freeman

1991-01-01

366

Outcome following isolated tricuspid valve replacement  

Microsoft Academic Search

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

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

2001-01-01

367

Diver's Suit Excess Gas Exhaust Valve.  

National Technical Information Service (NTIS)

A valve for controlling venting of excess gas from a diving suit includes a valve body housing first and second rubber check valves arranged in series. A control knob is rotatable on the valve body to selectively open or close outlet ports for venting gas...

C. H. Dickson

1979-01-01

368

2D PNEUMATIC DIGITAL SERVO VALVE  

Microsoft Academic Search

The digital servo valve is composed of 2-stage pneumatic servo valve developed with rotary and linear motions of a single spool, and stepper motor under continual control. To sustain the stability of the 2-stage pneumatic servo valve, an air damper is incorporated into the valve which is intended to increase both the stiffness of \\

Pei Xiang; Zheng Jiajin; Yang Jilong; Ruan Jian; R. Burton; P. Ukrainetz

369

Variable force solenoid pressure control for an automatic transmission  

Microsoft Academic Search

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

Lemieux

1989-01-01

370

Stemless ball valve  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

371

A reversible molecular valve.  

PubMed

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

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

2005-07-19

372

Multi-port valve  

DOEpatents

A multi-port valve for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO.sub.2) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets therethrough disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending therethrough disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind.

Lewin, Keith F. (Calverton, NY) [Calverton, NY

1997-04-15

373

Multi-port valve  

DOEpatents

A multi-port valve is described for regulating, as a function of ambient air having varying wind velocity and wind direction in an open-field control area, the distribution of a fluid, particularly carbon dioxide (CO{sub 2}) gas, in a fluid distribution system so that the control area remains generally at an elevated fluid concentration or level of said fluid. The multi-port valve generally includes a multi-port housing having a plurality of outlets there through disposed in a first pattern of outlets and at least one second pattern of outlets, and a movable plate having a plurality of apertures extending there through disposed in a first pattern of apertures and at least one second pattern of apertures. The first pattern of apertures being alignable with the first pattern of outlets and the at least one second pattern of apertures being alignable with the second pattern of outlets. The first pattern of apertures has a predetermined orientation with the at least one second pattern of apertures. For an open-field control area subject to ambient wind having a low velocity from any direction, the movable plate is positioned to equally distribute the supply of fluid in a fluid distribution system to the open-field control area. For an open-field control area subject to ambient wind having a high velocity from a given direction, the movable plate is positioned to generally distribute a supply of fluid in a fluid distribution system to that portion of the open-field control area located upwind. 7 figs.

Lewin, K.F.

1997-04-15

374

Check valve with poppet damping mechanism  

NASA Astrophysics Data System (ADS)

An inline check valve for a flow line is presented where the valve element is guided for inline travel forward and rearward of a valve sealing member and is spring biased to a closed sealing condition. One of the guides for the valve element includes a dashpot bore and plunger member to control the rate of travel of the valve element in either direction as well as provided a guiding function. The dashpot is not anchored to the valve body so that the valve can be functional even if the plunger member becomes jammed in the dashpot.

Morris, Brian G.

1993-08-01

375

Check valve with poppet damping mechanism  

NASA Technical Reports Server (NTRS)

An inline check valve for a flow line is presented where the valve element is guided for inline travel forward and rearward of a valve sealing member and is spring biased to a closed sealing condition. One of the guides for the valve element includes a dashpot bore and plunger member to control the rate of travel of the valve element in either direction as well as provided a guiding function. The dashpot is not anchored to the valve body so that the valve can be functional even if the plunger member becomes jammed in the dashpot.

Morris, Brian G. (inventor)

1993-01-01

376

Flow coefficients of monosleeve valves  

NASA Technical Reports Server (NTRS)

The flow coefficients of the intake and the exhaust ports of a sleeve-valve cylinder were measured by attaching the cylinder to a large tank and measuring the changes in pressure and temperature in the tank that were caused by short periods of air flow through the valve ports. The derivation of the equations on which the flow coefficients are based is given. The distribution of total pressure in the arms of the sleeve-valve intake manifold was measured. The arms are found to have as little as 75 percent of the total pressure within the manifold entrance.

Waldron, C D

1941-01-01

377

Is there a ten-year valve?  

PubMed

Since the start of the era of exclusive use of valve replacement in 1960, the only valve that has received continuous use [since 1962] has been the aortic homograft. Results with this valve indicate about a 60- to 70-percent 10-year survival rate. The next most continuously used designs have been the Smeloff-Cutter and the 1200-1260 series Starr-Edwards ball valves. Both of these valves have survival rates after 8 years of about 70%, and are, therefore, comparable to the homografts. More recently started series of homografts valves, tissue valves and prosthetic valves of various types appear to confer a better chance of 10-year survival than older valves in older series. Not all the improvements in survival rates can be ascribed to changes in valve design. Better selection of patients, improved intraoperative myocardial protection and better postoperative care all contribute to what appears to be progressive improvement in surgical results. PMID:944995

Paton, B C

1976-01-01

378

Bicarbon valve - European multicenter clinical evaluation  

Microsoft Academic Search

Objective: Fifteen collaborating centers in eight countries present their pooled experience with the new Bicarbon y bileaflet valve. Methods: Between 4\\/90 and 4\\/96, 1351 patients, 806 males and 545 females, aged 10 to 83, mean 58.4 ? 12.4, underwent valve implantation. Operations: aortic valve replacement (AVR), 726; mitral valve replacement (MVR), 475; double valve replacement (DVR), 150. Additional procedures: CABG,

J. B. Bormana; W. G. B. Brandsc; L. Camilleri; M. Cotrufoe; I. Gandjbakhch; C. Infantes; A. Khayati; F. Laborde; A. Pellegrini; A. Piwnica; B. Reichart; R. Sharony; R. Walesby; H. Warembourg; Clermond Ferrand; Grosshadern Klinikum

2010-01-01

379

Development of a fast valve for mitigating disruptions in tokamaks  

NASA Astrophysics Data System (ADS)

In support of our disruption mitigation profram, a fast gas valve has been constructed and tested on TEXTOR at FZJ Juelich. Its main features have been shown to be: (1) rapid response time: 0.5 ms; (2) amount of injected gas: variable, 2-1000 mbar×l (3) linear dependence of the number of injected particles on the gas pressure; (4) capability of working in a strong magnetic field; (5) sort of gas: any. The valve has the standard CF 35 flange, commonly used in vacuum engineering. All the components that have contact with vacuum were made of stainless steel, except for the closing aluminum piston. To prevent gas leaking directly from the bottles to the experimental vessel there are also two safety valves, closing the bottles before the shot. The required control equipment includes a high power supply and the combined controller for the safety valves and baratrons, both being able to work with TTL control signals. During tests and experiments on TEXTOR and ASDEX-Upgrade, the valve showed successful operation with three gas types: He, Ne, Ar.

Savtchkov, A.; Finken, K. H.; Mank, G.

2002-10-01

380

[Current status of cardiac valve prosthesis].  

PubMed

Cardiac valve replacement has been clinically applied for the final therapeutic management of valvular heart disease for the last over 20 years. Cardiac valve prostheses are mainly divided into mechanical and biological valves. As mechanical valve, tilting disc valve or bi-leaflet center opening valve made of antithrombogenic and durable pyrolytic carbon are now widely used. As biological valve, porcine aortic valve or bovine pericardial valve treated with glutaraldehyde-tanning for maintenance of cusp durability and pliability are exclusively used at the present time. However, valve related complications such as thrombus formation, embolic event, infection, hemolysis and valve sound in mechanical valve and valve failure and infection in biological valve are unavoidable clinical problems. Therefore, the cardiac valve prostheses should be selected on the basis of patients medical, social and geographical conditions. It is still necessary to develop the ideal prosthesis without the late complications in connection with decision of optimum surgical timing, and technological improvement of materials and structural design. PMID:4088196

Komatsu, S

1985-09-01

381

Simpler valve for reciprocating engines  

NASA Technical Reports Server (NTRS)

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

Akkerman, J. W.

1978-01-01

382

Living with Heart Valve Disease  

MedlinePLUS

... doctor if you have symptoms of infective endocarditis (IE). Symptoms of this heart infection include fever, chills, ... man-made valve or if you've had IE before. They may give you antibiotics before dental ...

383

Trileaflet valve hydrodynamic resistance assessment.  

PubMed

Valve hydrodynamic performance is usually assessed by effective orifice area, transvalvular resistance, regurgitation and blood damage effect. Some studies suggest effects in effective orifice area due to cardiovascular resistance, compliance and angle position of the valve. We suppose that silicone rubber valves under study have a good performance under different cardiovascular resistance conditions. Two in vitro experiments were made to test this hypothesis under constant and pulsatile flow rate. Transvalvular gradient pressure, transvalvular resistance, Gorling effective orifice area, effective orifice area in the ascending aorta and Reynolds numbers were estimated in both flow rates. Results suggest that cardiovascular resistance has no significant effect for this kind of valves, however resistance effect is observed in pumping pressure. Small transvalvular resistance and transvalvular pressure gradients were found. Gorlin effective orifice areas greater than 0.3 cm(2) have not viscosity effect. P-value 0.001 was found between Gorlin effective orifice area under constant and pulsatile flow rate. PMID:19162928

Garcia, J; Sacristan, E

2008-01-01

384

Models of aortic valve calcification.  

PubMed

Aortic valve stenosis is a complex inflammatory process, akin to arterial atherosclerosis, involving lymphocytic infiltrates, macrophages, foam cells, endothelial activation and dysfunction, increased cellularity and extracellular matrix deposition, and lipoprotein accumulation. A clonal population of aortic valve myofibroblasts spontaneously undergoes phenotypic transdifferentiation into osteoblast-like cells and forms calcific nodules in cell culture. Animal models complement these cell culture models by providing in vivo systems in which to study the complex molecular and cellular interactions that cause aortic valve disease in the native hemodynamic and biochemical environment. Whereas some species, such as swine, can develop spontaneous vascular and valvular atherosclerotic lesions, others, such as rabbits and mice, have not been shown to develop lesions naturally and require an inciting factor, such as hypercholesterolemia. In this article, we review the published cell culture and animal models available to study calcific aortic valve disease. PMID:17963676

Guerraty, Marie; Mohler Iii, Emile R

2007-09-01

385

A novel low-fidelity simulator for both mitral valve and tricuspid valve surgery: the surgical skills trainer for classic open and minimally invasive techniques†  

PubMed Central

OBJECTIVES Simulators have been proven to equip trainee surgeons with better skills than the traditional, standard approach to skill development. The purpose of this study was to develop a low-fidelity, low-cost, reusable and portable simulation device, which could provide training in nearly the full range of mitral valve surgery techniques, in both the classic, open approach as well as the minimally invasive approach. METHODS This novel simulator is made up of commonly available components. The basic elements are a classic baby bottle, with the associated feeding teat and screw ring, in combination with a sheet of dental dam. The detailed process for making this simulator is outlined in this article. Maximum suture tensile strength on the different components was tested with a digital force gauge. Reusability and the rate of wear as a result of suturing were documented. Total cost was calculated in euros (€). RESULTS This study resulted in a simulation model very similar in size to the actual anatomical dimensions of the mitral valve. Various pathological conditions, according to Carpentier's Functional Classification, could be simulated. This led to the possibility of providing training in several mitral valve surgical techniques. As the model developed, it became clear that it could also be used to practice tricuspid valve surgery techniques. Maximum mean suture tensions on the silicone teat and dental dam were 42.11 and 11.15 N/m2, respectively. The feeding teat started wearing after approximately 45 suture placements. Total cost of the study model was €5.14. CONCLUSIONS This relatively simple, low-cost, low-fidelity model can provide simulation training in nearly the full range of mitral valve and tricuspid valve surgical techniques, in both the classic open approach and the minimally invasive approach—and do so almost anywhere. Especially when used by young cardiothoracic surgeons in training, this model may contribute to the development of technical skills and procedural knowledge required for adequate performance in the operating room.

Verberkmoes, Niels J.; Verberkmoes-Broeders, Elizabeth M.P.C.

2013-01-01

386

Management of bicuspid aortic valve with or without involvement of ascending aorta and aortic root.  

PubMed

Patients with a bicuspid aortic valve (BAV) constitute a heterogeneous population with variable clinical presentation and complications. More than 50% of the patients who require aortic valve replacement have a BAV, a condition that may be associated with dilation of ascending aorta and aortic insufficiency caused by cusp disease or aortic root pathology. Of the potential BAV-related complications, dilation of the aortic root and ascending aorta are among the most serious. The dilation of ascending aorta and aortic root have been the subject of controversy. Whereas some surgeons believe that the dilation of the aorta is caused by the hemodynamic properties of the BAV, others believe that the dilation of the aortic root is secondary to genetic defects associated with the BAV. Management of a BAV should be tailored to each patient's clinical condition. The surgical approach varies from aortic valve replacement to combined aortic valve and root replacement to aortic-valve-sparing root replacement. PMID:23138607

Neragi-Miandoab, S

2014-06-01

387

Solid-state light valve  

Microsoft Academic Search

Recent developments in the solid-state light valve promise a high-quality projection display. The heart of the solid-state light valve is a cathode-ray tube which operates with a modulated and scanning write beam depositing charge on an electrooptic crystal target. The charge pattern on the target causes optical changes which result in modulation of an external light source. The tube incorporates

C. J. Salvo

1971-01-01

388

Kytococcus schroeteri prosthetic valve endocarditis.  

PubMed

We report the case of a 64-year-old male patient with a prosthetic aortic valve who presented with clinical features of endocarditis confirmed by transoesophageal echocardiography. His blood cultures were positive for a very rare and newly described organism-Kytococcus schroeteri. The patient underwent aortic valve replacement and a 6-week course of intravenous antibiotics. This is the fifth reported case of endocarditis associated with this organism. PMID:22778375

Yousri, Taher; Hawari, Mohammad; Saad, Rasheed; Langley, Steve

2010-01-01

389

Kytococcus schroeteri prosthetic valve endocarditis  

PubMed Central

We report the case of a 64-year-old male patient with a prosthetic aortic valve who presented with clinical features of endocarditis confirmed by transoesophageal echocardiography. His blood cultures were positive for a very rare and newly described organism—Kytococcus schroeteri. The patient underwent aortic valve replacement and a 6-week course of intravenous antibiotics. This is the fifth reported case of endocarditis associated with this organism.

Yousri, Taher; Hawari, Mohammad; Saad, Rasheed; Langley, Steve

2010-01-01

390

Liquid-blocking check valve  

DOEpatents

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

Merrill, J.T.

1982-09-27

391

A Parylene MEMS Electrothermal Valve  

Microsoft Academic Search

The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current)

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

2009-01-01

392

Failsafe gas closed safety valve  

SciTech Connect

A subsurface well safety valve is described for controlling the fluid flow through a well conduit comprising: a housing having a bore; a valve closure member moving between open and closed positions for controlling the fluid flow through the bore; a flow tube telescopically moving in the housing for controlling the movement of the valve closure member; a piston and cylinder assembly positioned in the housing and one of the piston and cylinder engages the flow tube, a first side of the assembly adapted to be in communication with a fluid control passageway to the well surface; a gas chamber in the housing in communication with the second side of the assembly acting on the assembly in a direction to close the valve; spring means between the housing and the flow tube acting on the flow tube in a direction to close the valve; seal means between the piston and cylinder; and openable and closable equalizing means for equalizing fluid pressure on opposite sides of the piston and cylinder assembly in the event of a failure in the seal means thereby allowing the spring means to close the valve.

Blizzard, W.A.

1987-04-28

393

Venular valves and retrograde perfusion.  

PubMed

Forced retrograde perfusion through the venous system with arterial blood can provide adequate oxygen to peripheral tissues at rest through veno-capillary networks which is the basis for surgical restoration of blood flow by distal vein arterialization (DVA). To be successful such surgery requires disruption of valve leaflets in the veins, which can be accomplished easily in the larger vessels. However, the smallest veins (venules) of less than 100 ?m in diameter, also possess valves, are distributed widely throughout all tissues and are too fine for any effective surgical interference. Thus venular valves cannot be disrupted or dissected with presently available technology. Nevertheless, clinical observations suggest that retrograde peripheral blood flow is rapidly established after DVA surgery. There is as yet no rational explanation for this phenomenon. In the present study, using Laplace's law, we attempt to elucidate the mechanical properties of venules and their valves. We speculate that the remarkably thin venular walls (and especially those of the smaller vessels which have the thinnest walls), are capable of considerable, rapid distension when subjected to increased hemostatic pressure. The increase in diameter of venules in response to the increased blood pressure renders their valve leaflets incompetent, so that the valves themselves cannot close the vessel lumen. In addition, the thin bicuspid leaflets may also be forced open retrogradely by the increased blood pressure. PMID:24729249

Koyama, Tomiyasu; Sugihara-Seki, Masako; Sasajima, Tadahiro; Kikuchi, Sinsuke

2014-01-01

394

Prediction of late results following valve replacement in aortic valve stenosis. Seventeen years of follow-up examined with the Cox regression analysis.  

PubMed

A total of 122 patients (mean age: 55 years, range 20-75 years) were alive 30 days after isolated aortic valve replacement (AVR) performed in 1965-73 for aortic valve stenosis (AS). Cold chemical Bretschneider cardioplegia was used in all operations. The maximum follow-up was 17 years, mean 9 years. The 10-year cumulative survival +/- SE was 63 +/- 4%. Twenty-one preoperative clinical, invasive and valve-related variables were entered into a Cox regression analysis. Variables with independent predictive value regarding long-term survival were: Left ventricular failure (regression coefficient: b = 1.078, p less than 0.0002), age (b = 0.749, p less than 0.009), pulse pressure (b = -0.663, p less than 0.02) and cardio-thoracic index (CTI) (b = 0.603, p less than 0.04). Based on these variables, a prognostic index with 16 different risk groups was made. In the "best" group (n = 8), the observed 10-year survival +/- SE was 88 +/- 11%, compared to 13 +/- 12% for the "worst" group (n = 8). Multivariate analysis of complication-free survival showed that the total valve-related complication-rate (VRC) (4.2/100 pat.-yrs) was influenced by valve type (Starr-Edwards ball valves, n = 118, versus Lillehei-Kaster and Smeelof-Cutter valves, n = 4) and CTI. The valve- and heart-related events (VRC together with late myocardial infarctions and pacemaker implantations, 6.5/100 pat.-yrs) depended on CTI and previous myocardial infarction. No predictors of thromboembolism (1.6/100 pat.-yrs) or coumarin-related hemorrhage (1.8/100 pat.-yrs) could be identified.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2447672

Lund, O; Vaeth, M

1987-10-01

395

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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.

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

1993-01-01

396

Abrasion resistant valves cut platform maintenance cost  

SciTech Connect

Shell Exploration and Production, operator of Brent field in the UK North Sea, turned to Anglo-US valve maker Serck Audco Valves for help in solving persistent valve maintenance problems. Brent Charlie platform was selected as a test site for the supplier`s new line of abrasion-resistant valves. The most common failure cause is abrasion by solids in the line fluid, particularly sand, which damages even stainless steel and Duplex valve seats, creating leak paths which prevent valve sealing. Serck Audco manufacturers the Super-H all-metal pressure-balanced plug valve, which has proved particularly resistant to erosion in some of the world`s harshest operating environments. The paper describes the valve`s extra abrasion resistance and the Brent Charlie test.

NONE

1997-02-01

397

Pressure control valve. [inflating flexible bladders  

NASA Technical Reports Server (NTRS)

A control valve is provided which is adapted to be connected between a pressure source, such as a vacuum pump, and a pressure vessel so as to control the pressure in the vessel. The valve comprises a housing having a longitudinal bore which is connected between the pump and vessel, and a transversely movable valve body which controls the air flow through an air inlet in the housing. The valve body includes cylindrical and conical shaped portions which cooperate with reciprocally shaped portions of the housing to provide flow control. A filter in the air inlet removes foreign matter from the air. The bottom end of the valve body is screwed into the valve housing control knob formed integrally with the valve body and controls translation of the valve body, and the opening and closing of the valve.

Lambson, K. H. (inventor)

1980-01-01

398

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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.

Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

1993-03-16

399

[Historical evolution of prosthetic heart valves].  

PubMed

The historical evolution of the prosthetic heart valves is resumed, quoting the first experimental steps, the conditions that a prosthesis has to fulfil, and the first clinical attempts with the Hufnagel's valve in the treatment of the aortic insufficiency (September 11, 1952) and with the Chesterman's in the pathology of the mitral valve (July 22, 1955) till the Starr Edwards' ball valve (Agoust 12, 1960). The characteristics of the different types of ball valve are described (Harken, Smeloff, etc), disc valves (Kay-Shiley, Beall, Lillehei-Nakib etc.), tilting disc valves (Bjork-Shiley, Hall-Kaster, Omniscience etc), bileaflet valves ( St. Jude and others) and biological valves, using autologous tisues (diaphragm, fascia lata, pericardium) homologous (aortic and mitral valves, duramater) and heterologous (porcine and bovine valves, Carpentier-Edwards, Hancock, Ionescu's valve of bovine pericardium), to conclude with the new trends with valves made from autologous cells, the valves made with polymers, those based on the concept of flexible tubes and finally with those used by percutaneous transcatheter implantation (Boudjemline y Bonhoeffer. Cribier.). PMID:17451095

Tamames Escobar, Santiago

2006-01-01

400

Pressure operated circulation valve  

SciTech Connect

This patent describes a circulating valve for use in a tubing string in a wellbore traversing earth formations where the annulus between the tubing string and the well bore contains a liquid. It comprises a tubular mandrel assembly having an annular recess; a tubular sleeve assembly slidably mounted in the annular recess, the sleeve assembly including first and second sleeve member; a circulating port in the tubular mandrel assembly intermediate of the length of the annular recess; the sleeve members having overlapped portions and seal means cooperating with the sleeve member and the mandrel assembly for defining an annular chamber in fluid communication with the circular port in a first position on the mandrel assembly, the sleeve members being independently movable longitudinally of the mandrel assembly; first and second release means for respectively releasably connecting the first sleeve member and the second sleeve member to the tubular assembly and for releasably maintaining the annular chamber in fluid communication with the port in the first position; and one of the sleeve members being responsive to a pressure applied in the annular chamber for releasing one of the first and second releasable means so that the one sleeve member moves longitudinally to a second position for placing the interior of the tubular mandrel assembly in fluid communication through the port with the exterior about the sleeve member.

Cochran, C.B.

1991-09-17

401

Annular flow diverter valve  

DOEpatents

A valve for diverting flow from the center of two concentric tubes to the annulus between the tubes or, operating in the reverse direction, for mixing fluids from concentric tubes into a common tube and for controlling the volume ratio of said flow consists of a toroidal baffle disposed in sliding engagement with the interior of the inner tube downstream of a plurality of ports in the inner tube, a plurality of gates in sliding engagement with the interior of the inner tube attached to the baffle for movement therewith, a servomotor having a bullet-shaped plug on the downstream end thereof, and drive rods connecting the servomotor to the toroidal baffle, the servomotor thereby being adapted to move the baffle into mating engagement with the bullet-shaped plug and simultaneously move the gates away from the ports in the inner tube and to move the baffle away from the bullet-shaped plug and simultaneously move the gates to cover the ports in the inner tube.

Rider, Robert L. (Walkersville, MD)

1980-01-01

402

Valve operating system for internal combustion engine  

SciTech Connect

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 to open and close the intake and exhaust passages, respectively, and a valve operating mechanism having an intermittent operating function of rotatively driving the valve bodies of the intake and exhaust rotary valves in response to movement of the piston to provide an opening and closing control for the intake and exhaust rotary valves, and holding the rotary valve bodies in valve-opening and closing positions for respective predetermined periods of time, wherein the valve operating mechanism includes cam means adapted to be continuously rotated in one direction in response to the movement of the piston, rocker arms abutting the cam means and adapted to swing within a predetermined angle in accordance with the rotation of the cams, and rotary shafts each having one of the spherical valve bodies secured to one of the opposite ends thereof and adapted to reciprocally rotate between the valve-opening and closing positions of the valve body around an axis of the rotary shaft in accordance with the swinging movement of the rocker arm upon receiving a driving force from the rocker arm on the other end thereof, and the spherical valve bodies being each supported within the cylinder head through a valve seat member, and a seal spring being interposed between the valve seat member and the cylinder head.

Matsuura, M.; Nakamori, M.; Kuroki, M.

1988-10-11

403

Spring-Loaded Joule-Thomson Valve  

NASA Technical Reports Server (NTRS)

Improved design reduces clogging and maintains constant pressure drop as flow rate varies. Spring-Loaded Joule-Thomson Valve pressure drop regulated by spring pushing stainless-steel ball against soft brass seat. Pressure drop remains nearly constant, regardless of helium flow rate and of any gas contaminants frozen on valve seat. Because springloaded J-T valve maintains constant pressure drop, upstream roomtemperature throttle valve adjusts flow rate precisely for any given upstream pressure. In addition, new valve relatively invulnerable to frozen gas contaminants, which clog fixed-orifice J-T valves.

Jones, J. A.; Britcliffe, M. J.

1986-01-01

404

Automatic control apparatus for engine throttle valve  

SciTech Connect

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.

Ejiri, Y.; Ito, T.

1988-04-05

405

Scaffolds for tissue engineering of cardiac valves.  

PubMed

Tissue engineered heart valves offer a promising alternative for the replacement of diseased heart valves avoiding the limitations faced with currently available bioprosthetic and mechanical heart valves. In the paradigm of tissue engineering, a three-dimensional platform - the so-called scaffold - is essential for cell proliferation, growth and differentiation, as well as the ultimate generation of a functional tissue. A foundation for success in heart valve tissue engineering is a recapitulation of the complex design and diverse mechanical properties of a native valve. This article reviews technological details of the scaffolds that have been applied to date in heart valve tissue engineering research. PMID:24675108

Jana, S; Tefft, B J; Spoon, D B; Simari, R D

2014-07-01

406

Aortic valve replacement in elderly patients.  

PubMed

During the years 1965--75, 98 patients more than 65 years of age had aortic valve replacement in our hospital, 24 ball valves and 74 disc valves inserted in their aortic orifice. Actuarial analysis of survival in these patients shows that the operative risk is slightly higher in elder than in younger patients. The survival curve for the following years for those who had disc valve implantation runs parallel to that of younger patients, while those who had ball valve implantation showed a more rapid fall in survival after 3 years. After 10 years, only 30% of patients with ball valve transplantation were alive. PMID:495221

Storstein, O; Efskind, L

1979-01-01

407

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

408

21 CFR 870.3925 - Replacement heart valve.  

Code of Federal Regulations, 2010 CFR

...Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any of the heart's natural valves. This device includes valves...

2009-04-01

409

21 CFR 870.3925 - Replacement heart valve.  

Code of Federal Regulations, 2010 CFR

...Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any of the heart's natural valves. This device includes valves...

2010-04-01

410

42 CFR 84.158 - Exhalation valve leakage test.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Exhalation valve leakage test. 84.158 Section...RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...

2013-10-01

411

42 CFR 84.158 - Exhalation valve leakage test.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Exhalation valve leakage test. 84.158 Section...RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.158 Exhalation valve leakage test. (a) Dry exhalation valves and valve seats will be...

2010-10-01

412

Failure and life cycle evaluation of watering valves.  

PubMed

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

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

2011-09-01

413

MODELING AND VALIDATION OF A HIGH SPEED ROTARY PWM ON\\/OFF VALVE  

Microsoft Academic Search

Efficient high-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 system band- width and reduce output pressure ripple by enabling higher PWM frequencies. Our approach to achieving high speed and large flow area with low actuation power is a unidirectional

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

2009-01-01

414

Annulus sliding sleeve valve  

SciTech Connect

This patent describes, in a well having a tubing hanger for supporting a string of tubing within casing, the tubing hanger having a lower exterior cylindrical portion, a passage extending from an upper end of the tubing hanger to a port on the cylindrical portion in communication with an annulus between the tubing and casing, an improved valve for selectively opening and closing the port. It comprises in combination: a closure sleeve slidingly mounted to the exterior of the cylindrical portion and having a lower edge; means for moving the closure sleeve between a lower position in which the lower edge is below the port for blocking the port and an upper position in which the lower edge is above the port; a protector sleeve slidingly mounted to the exterior of the cylindrical portion below the closure sleeve and having an upper edge. The upper edge of the protector sleeve being engaged by the lower edge of the closure sleeve to push the protector sleeve downward with the closure sleeve as the closure sleeve moves to the lower position; means for urging the protector sleeve upward for causing the protector sleeve to move upward as the closure sleeve moves toward the upper position; and means for stopping upward movement of the protector sleeve before the upper edge of the protector sleeve passes the port and before the closure sleeve reaches the upper position, causing the lower edge of the closure sleeve to separate from the upper edge of the protector sleeve to expose the port to the annulus.

Lilley, R.O.

1989-07-18

415

Quadricuspid Aortic Valve Diagnosed by Cardiac CT  

PubMed Central

Quadricuspid aortic valves are rare congenital anomalies which can be diagnosed by various imaging modalities. Described is the case of a 77 year old female with a quadricuspid aortic valve diagnosed by cardiac CT.

D'Mello, Nisha; Tandon, Vikas; Chow, Benjamin J. W.

2011-01-01

416

Stem clutch for motor driven valve  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

417

Flow Characteristics and Accuracy of Control Valve.  

National Technical Information Service (NTIS)

The purpose of this work was to examine the flow characteristics and accuracy of control valve. The research was divided into three different parts. At first, flow characteristics of control valve were studied, and general solution was determined for the ...

J. Pyoetsiae

1989-01-01

418

49 CFR 229.109 - Safety valves.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined...

2010-10-01

419

Aortic valve repair: indications and outcomes.  

PubMed

Aortic valve replacement has traditionally been the treatment of choice for patients with aortic valve insufficiency with or without aortic root pathology. Aortic valve repair is emerging as an attractive treatment alternative that avoids the long-term risks associated with prosthetic valve implantation including thromboembolism, endocarditis, prosthetic valve deterioration, and anticoagulation related hemorrhage. Important achievements in this discipline have occurred over the past decade including development and refinement of valve preserving aortic root replacement techniques, development of a classification system for aortic insufficiency, surgical approaches to cusp disease with varying cusp anatomy. As surgical techniques for aortic valve repair continue to evolve, clinical outcomes up to and beyond the first decade are promising with excellent survival and low risk of valve related events. PMID:24743899

Boodhwani, Munir; El Khoury, Gebrine

2014-06-01

420

46 CFR 64.67 - Shutoff valve.  

Code of Federal Regulations, 2013 CFR

...SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff valve may not be locatedâ (a) Between the tank...

2013-10-01

421

How Is Heart Valve Disease Diagnosed?  

MedlinePLUS

... the severity of your heart valve disease. Cardiac MRI Cardiac MRI uses a powerful magnet and radio waves to make detailed images of your heart. A cardiac MRI image can confirm information about valve defects or ...

422

Bistable (Latching) Solenoid Actuated Propellant Isolation Valve.  

National Technical Information Service (NTIS)

The design, fabrication, assembly and test of a development configuration bistable (latching) solenoid actuated propellant isolation valve suitable for the control hydrazine and liquid fluorine to an 800 pound thrust rocket engine is described. The valve ...

H. Wichmann H. H. Deboi

1979-01-01

423

Parachute tricuspid valve in an asymptomatic adult.  

PubMed

Parachute tricuspid valve is a rare anomaly usually reported in small children. This report describes transthoracic and trans-oesophageal echocardiographic (TEE) features of parachute mitral valve in an adult patient. PMID:22572436

Mohan, Jagdish C; Shekhar, Chandra; Mohan, Vipul; Kaur, Bimalpreet; Singh, Shivesh Kumar

2012-01-01

424

Intra-Urethral Valve with Integral Spring.  

National Technical Information Service (NTIS)

The invention relates to prosthetic urethral valves for controlling urinary continence. More particularly, the invention relates to a prosthetic urethral valve having an integral spring member which may be installed totally within a patient's urethra with...

S. Leighton

1990-01-01

425

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

426

The influence of laser hardening on wear in the valve and valve seat contact  

Microsoft Academic Search

In internal combustion engines it is important to manage the wear in the valve and valve seat contact in order to minimise emissions and maximise economy. Traditionally wear in this contact has been controlled by the use of a valve seat insert and the careful selection of materials for both the valve and the insert. More recently, due to the

T. Slatter; H. Taylor; R. Lewis; P. King

2009-01-01

427

Check valve installation in pilot operated relief valve prevents reverse pressurization  

NASA Technical Reports Server (NTRS)

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.

Oswalt, L.

1966-01-01

428

Hydrodynamic function of tilting disc prostheses and bileaflet valves in double valve replacement  

Microsoft Academic Search

Objective.To determine the energy loss attributable to prosthetic valve size and design in double valve replacement, energy consumption of mitral valves (size #25 to #29), of two different designs (Bjork Shiley tilting disc and Carbomedics bileaflet valves), in combination with a small (#21) and large sized (#27) aortic prosthesis, were analyzed in a flow simulator.

J. Laas; A. Campbell; G. Richard

1996-01-01

429

Mechanical Hemolysis Associated with a Bioprosthetic Mitral Valve Combined with a Calcified Aortic Valve Stenosis  

Microsoft Academic Search

We report a case of severe mechanical hemolysis occurring 8 years after insertion of a bioprosthetic mitral valve in a patient who also suffered from aortic valve stenosis. It is suggested that the coexistence of two malfunctioning valves may lead to hemolysis via hemodynamic and turbulence alteration and that this condition is more frequent than expected for isolated valve involvement.Copyright

Kostas Konstantopoulos; Tasos Kasparian; John Sideris; Ersi Voskaridou; Dimitris Loukopoulos

1994-01-01

430

Prosthetic Mitral Valve Leaflet Escape  

PubMed Central

Leaflet escape of prosthetic valve is rare but potentially life threatening. It is essential to make timely diagnosis in order to avoid mortality. Transesophageal echocardiography and cinefluoroscopy is usually diagnostic and the location of the missing leaflet can be identified by computed tomography (CT). Emergent surgical correction is mandatory. We report a case of fractured escape of Edward-Duromedics mitral valve 27 years after the surgery. The patient presented with symptoms of acute decompensated heart failure and cardiogenic shock. She was instantly intubated and mechanically ventilated. After prompt evaluation including transthoracic echocardiography and CT, the escape of the leaflet was confirmed. The patient underwent emergent surgery for replacement of the damaged prosthetic valves immediately. Eleven days after the surgery, the dislodged leaflet in iliac artery was removed safely and the patient recovered well.

Kim, Darae; Hun, Sin Sang; Cho, In-Jeong; Shim, Chi-Young; Ha, Jong-Won; Chung, Namsik; Ju, Hyun Chul; Sohn, Jang Won

2013-01-01

431

Bistable diverter valve in microfluidics  

NASA Astrophysics Data System (ADS)

Bistable diverter valves are useful for a large number of no-moving-part flow control applications, and there is a considerable interest in using them also in microfluidics, especially for handling small pressure-driven flows. However, with decreasing Reynolds number, the Coanda effect—on which the flow diverting effect depends—becomes less effective. Authors performed a study, involving flow visualisation, PIV experiments, measurements of the flow rates, and numerical flowfield computations, aimed at clarifying behaviour of a typical fluidic valve at low Reynolds numbers. A typical fluidic valve originally developed for high Re operation was demonstrated to be useful, though with progressively limited efficiency, down to surprisingly low Re values as small as Re = 800. Also observed was a previously not reported discontinuation in the otherwise monotonic decrease in performance at Re between 1,500 and 2,000.

Tesa?, V.; Bandalusena, H. C. H.

2011-05-01

432

Propellant isolation shutoff valve program  

NASA Technical Reports Server (NTRS)

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.

Merritt, F. L.

1973-01-01

433

Lost-motion valve actuator  

SciTech Connect

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.

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

1987-04-07

434

Problems associated with mechanical heart valve sounds  

Microsoft Academic Search

A cross-sectional study of 50 randomly selected patients 12-36 months following mechanical heart valve replacement with Bjork-Shiley tilting disc valves was undertaken to investigate the factors which affect perception of, and reaction to, sounds generated by mechanical heart valves implanted in patients. Numerous problems were generated by the valves, including annoyance (68%), sleep disturbance (52% in patients; and 46% in

D. Limb; P. H. Kay; A. J. Murday

1992-01-01

435

Computer-controlled Teflon flow control valve  

NASA Astrophysics Data System (ADS)

A butterfly vane valve is described for the servo control of a gas or liquid flow. The valve is suitable for reactive species since nearly all wetted parts are Teflon. The valve is operated by a servo motor that is controlled by a dedicated microprocessor programmed in BASIC. The valve offers many other desirable features, including constant and relatively small surface area, low dead volume, high conductance in the full-open position, vacuum compatibility, firmware control, and scalability.

Gao, R. S.; McLaughlin, R. J.; Schein, M. E.; Neuman, J. A.; Ciciora, S. J.; Holecek, J. C.; Fahey, D. W.

1999-12-01

436

The use of MAVIS II to integrate the modeling and analysis of explosive valve interactions  

SciTech Connect

The MAVIS II computer program provides for the modeling and analysis of explosive valve interactions. This report describes the individual components of the program and how MAVIS II is used with other available tools to integrate the design and understanding of explosive valves. The rationale and model used for each valve interaction is described. Comparisons of the calculated results with available data have demonstrated the feasibility and accuracy of using MAVIS II for analytical studies of explosive valve interactions. The model used for the explosive or pyrotechnic used as the driving force in explosive valves is the most critical to be understood and modeled. MAVIS II is an advanced version that incorporates a plastic, as well as elastic, modeling of the deformations experienced when plungers are forced into a bore. The inclusion of a plastic model has greatly expanded the use of MAVIS for all categories (opening, closure, or combined) of valves, especially for the closure valves in which the sealing operation requires the plastic deformation of either a plunger or bore over a relatively large area. In order to increase its effectiveness, the use of MAVIS II should be integrated with the results from available experimental hardware. Test hardware such as the Velocity Interferometer System for Any Reflector (VISAR) and Velocity Generator test provide experimental data for accurate comparison of the actual valve functions. Variable Explosive Chamber (VEC) and Constant Explosive Volume (CEV) tests are used to provide the proper explosive equation-of-state for the MAVIS calculations of the explosive driving forces. The rationale and logistics of this integration is demonstrated through an example. A recent valve design is used to demonstrate how MAVIS II can be integrated with experimental tools to provide an understanding of the interactions in this valve.

Ng, R.; Kwon, D.M.

1998-12-31

437

Organic Evaporator steam valve failure  

SciTech Connect

DWPF Technical has requested an analysis of the capacity of the organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS).

Jacobs, R. A.

1992-09-29

438

[Early bioprosthetic mitral valve thrombosis].  

PubMed

We present a case of a 70 year-old woman operated due to severe mitral regurgitation. Early after surgery transthoracic echocardiography revealed the decreased effective orifice area of the implanted bioprosthetic valve and the stenotic features of transvalvular flow. Transesophageal echocardiography (TEE) disclosed a thrombotic cause of heterograft dysfunction. Due to the clinical deterioration and the unclear cause of prosthesis stenosis, the patient was reoperated. Intra-operatively bioprosthetic mitral valve thrombosis was confirmed. Precipitating factors of this rare complication including cardiac device related infective endocarditis (CDRIE) and the diagnostic applicability of TEE in this clinical scenario are discussed. PMID:22427084

Tkaczyszyn, Micha?; Olbrycht, Tomasz; Kustrzycka Kratochwil, Dorota; Sokolski, Mateusz; Sukiennik Kujawa, Ma?gorzata; Skiba, Jacek; Gemel, Marek; Banasiak, Waldemar; Jankowska, Ewa A; Ponikowski, Piotr

2012-01-01

439

Fast-acting valve actuator  

DOEpatents

A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

Cho, Nakwon (Knoxville, TN)

1980-01-01

440

Balloon valuloplasty prior to transcatheter valve-in-valve implantation in a degenerated Mitroflow aortic bioprosthesis.  

PubMed

Transcatheter valve-in-valve implantation is an emerging treatment option for high-risk patients with failing aortic bioprostheses. The presence of the prosthesis stents is thought to prevent coronary artery obstruction, a known complication of transcatheter aortic valve implantation in the native aortic valve. The Sorin Mitroflow aortic bioprosthesis (Sorin Group, Saluggia, Italy) has a particular design in that the pericardial leaflets are mounted outside the valve stent. As a consequence, the pericardial leaflets of this prosthesis may be displaced well away from the stents during the deployment of transcatheter valves. This might explain why both the cases of coronary occlusion following valve-in-valve implantation reported to date occurred in patients with a malfunctioning Mitroflow bioprosthesis. We describe a patient with a malfunctioning 25 mm Mitroflow bioprosthesis successfully treated by percutaneous transcatheter valve-in-valve implantation, and discuss the role that balloon aortic valvuloplasty plays in the performance of this delicate procedure. PMID:22744728

Cerillo, Alfredo Giuseppe; Berti, Sergio; Glauber, Mattia

2013-05-01

441

Compression release retarder with valve motion modifier  

SciTech Connect

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.

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

1987-11-17

442

Pentacuspid aortic valve diagnosed by transoesophageal echocardiography  

PubMed Central

Congenital aortic valve anomalies are quite a rare finding in echocardiographic examinations. A case of a 19 year old man with a pentacuspid aortic valve without aortic stenosis and regurgitation, detected by transoesophageal echocardiography, is presented.???Keywords: pentacuspid aortic valve; echocardiography

Cemri, M; Cengel, A; Timurkaynak, T

2000-01-01

443

Whitey SCHE Gauge and Root Valves  

SciTech Connect

These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHa System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHa supply line.

MISKA, C.R.

2000-09-11

444

Whitey SCHE Gauge and Root Valves  

SciTech Connect

These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHe System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHe supply line.

MISKA, C.R.

2000-09-03

445

Whitey SCHE Gauge and Root Valves  

SciTech Connect

These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHe System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHe supply line.

VAN KATWIJK, C.

2000-06-21

446

49 CFR 195.258 - Valves: General.  

Code of Federal Regulations, 2013 CFR

... 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...

2013-10-01

447

49 CFR 195.116 - Valves.  

Code of Federal Regulations, 2013 CFR

...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...

2013-10-01

448

49 CFR 195.260 - Valves: Location.  

Code of Federal Regulations, 2013 CFR

...Transportation 3 2013-10-01 2013-10-01 false Valves: Location. 195.260 Section 195.260 Transportation...LIQUIDS BY PIPELINE Construction § 195.260 Valves: Location. A valve must be installed at each of the following...

2013-10-01

449

Dynamic Analysis of the Bioprosthetic Heart Valve  

Microsoft Academic Search

This paper establishes parametric model of the bioprosthetic heart valve via computer aided design. Dynamic finite element analysis is used along with a geometrically accurate model of the bioprosthetic heart valve. The stress distribution of cylindrical and paraboloidal valve leaflets under the same load is analyzed as the leaflets are closed. The finite element analysis results show that the stress

Quan Yuan; Xin Ye; Hua Cong

2010-01-01

450

Valve for fuel pin loading system  

DOEpatents

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.

Christiansen, David W. (Kennewick, WA)

1985-01-01

451

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.

2008-11-04

452

Air-cooled overhead-valve engine  

Microsoft Academic Search

This patent describes an air-cooled overhead-valve internal combustion engine. The engine is composed of a crankcase with a crankshaft, a cylinder block with a cylinder head and a combustion chamber mounted in the crankcase. At least a pair of intake and exhaust valves installed in intake and exhaust ports are formed in the cylinder head. A valve drive system mounted

Shirai

1987-01-01

453

Supplemental air valve for internal combustion engine  

Microsoft Academic Search

A valve for attachment in the PCV system of an internal combustion engine for regulating the admission of supplemental air to the crank case blow-by return, comprising: (a) a valve body defining a bore, the body having an inlet and an outlet connection defining a passageway through the valve for the blow-by return, the body further defining a port for

Pankow

1987-01-01

454

LVAD support in patients with bioprosthetic valves  

Microsoft Academic Search

The presence of mechanical or bioprosthetic valves has traditionally excluded patients from mechanical circulatory support. However, several centers have now developed algorithms for the surgical management of native or prosthetic valve disease in patients requiring left ventricular assist device insertion. We report adverse events associated with bioprosthetic valves in the mitral and tricuspid positions in 2 patients who received long-term

Alessandro Barbone; Vivek Rao; Mehmet C. Oz; Yoshifumi Naka

2002-01-01

455

Valve for fuel pin loading system  

DOEpatents

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.

Christiansen, D.W.

1984-01-01

456

Research on performance of slide-valve in water hydraulic servo-valve with hydrostatic bearing  

Microsoft Academic Search

In order to optimize the motion characteristics of slide-valve in water hydraulic servo-valve. Hydrostatic bearing technology has been used between valve core and sleeve. The research on performance about the static characteristics of slide-valve in water hydraulic servo-valve with hydrostatic bearing structure and traditional throttle with fixed orifice has been carried. The mathematical model of the pressure-flow characteristics, the pressure

Wang Xinhua; Zheng Jian; Sun Shuwen; Li Wei; Chang Jiaqing

2010-01-01

457

Terminal warm blood cardioplegia in mitral valve replacement: prospective study.  

PubMed

Terminal warm blood cardioplegia has had a profound impact on cardiac surgery, especially in coronary artery bypass surgery, but there have been few studies on its use in mitral valve replacement. The purpose of this study was to determine whether terminal warm blood cardioplegia offers any advantages in mitral valve replacement. Forty patients with mitral valve disease were prospectively randomized to one of two groups of 20 with different techniques of myocardial protection: group A had cold blood cardioplegia, and group B had cold blood cardioplegia with terminal warm blood cardioplegia. Intraoperative and postoperative variables were used to assess primary outcomes. Postoperative troponin T release was measured as a secondary outcome. Improved spontaneous recovery of sinus rhythm was observed in group B, but the difference was not significant. The maximum doses of inotropics, duration of inotropic support, intensive care unit stay, and postoperative left ventricular ejection fraction were similar in both groups. Troponin T release at 0 and 6 h postoperatively was not different between the two groups. This study did not find any benefit of terminal warm blood cardioplegia in either clinical outcome or troponin T release after mitral valve replacement. PMID:16551821

Rergkliang, Chareonkiat; Chetpaophan, Apirak; Chittithavorn, Voravit; Vasinanukorn, Prasert; Chowchuvech, Vorapong

2006-04-01

458

Control system for a continuously variable transmission  

SciTech Connect

This patent describes a control system for a continuously variable belt-drive transmission having a selector device including a drive range position, a drive pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc, a driven pulley having a hydraulically shiftable disc and a servo chamber for shifting the disc, and a belt engaged with both the pulleys, an hydraulic control circuit for supplying oil to the servo chambers and for draining the servo chambers, the hydraulic control circuit being provided with a pressure regulator valve for providing a line pressure and a transmission ratio control valve for applying the line pressure to the servo chamber of the drive pulley. The improvement comprises: a first drain passage from the pressure regulator valve; a second drain passage from the transmission ratio control valve; a first check valve provided in the first drain passage and a second check valve provided in the second drain passage for building up supplementary low pressure in both drain passages at upstream of both the check valves; a supplementary oil passage communicating both the first and second drain passages at upstream of the check valves for supplying a part of drain oil to the servo chamber of the drive pulley.

Sakai, Y.

1987-11-03

459

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

460

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS  

Microsoft Academic Search

Direct pump control of hydraulic systems is more energy efficient than throttle valve based methods to control hydra ulic systems. This requires variable displacement pumps that are responsive and capable of electronic control. Such Electronic Displacement Controlled (EDC) pumps tend to be significantl y larger, heavier and more expensive than fixed displacement c oun- terparts. In addition, achievable control bandwidths

Perry Y. Li; Cassie Y. Li; Thomas R. Chase

461

Clinical Use of a New Mitral Disc Valve  

PubMed Central

A disc valve of new design was used successfully for the replacement of the mitral valve in patients with rheumatic mitral valve disease. This valve would appear to have the following advantages over the mitral ball valve prosthesis: • Lower left atrial pressure after replacement. • Elimination of the hazard of left ventricular outflow tract obstruction with mitral valve replacement. • Decreased incidence of thromboembolization. • Abolition of possibility of ventricular septal irritation. Despite the better outlook for this valve compared with the ball valve for mitral valve substitution, the mitral valve should always be repaired whenever feasible. Repair is possible in the majority of patients. ImagesFigure 1.

Kay, Jerome Harold; Tsuji, Harold K.; Redington, John V.; Kawashima, Yasunaru; Kagawa, Yuzuru; Yamada, Takashi; Caponegro, Peter; Mendez, Adolfo

1967-01-01

462

Hydraulic servo control spool valve  

DOEpatents

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.

Miller, Donald M. (Sunnyside, WA)

1983-01-01