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Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

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

E-Print Network [OSTI]

ESTIMATION OF EXHAUST MANIFOLD PRESSURE IN TURBOCHARGED GASOLINE ENGINES WITH VARIABLE VALVE TIMING in turbocharged gasoline engines with variable valve timing requires knowledge of exhaust mani- fold pressure, Pe control systems for gasoline engines rely heavily on feedforward air-fuel ratio (A/F) control to meet

Grizzle, Jessy W.

2

Closed-loop, variable-valve-timing control of a controlled-auto-ignition engine  

E-Print Network [OSTI]

The objective of this study was to develop a closed-loop controller for use on a Controlled-Auto- Ignition (CAI) / Spark-Ignition (SI) mixed mode engine equipped with a variable-valve-timing (VVT) mechanism. The controller ...

Matthews, Jeffrey A., 1970-

2004-01-01T23:59:59.000Z

3

Variable valve timing in a homogenous charge compression ignition engine  

DOE Patents [OSTI]

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

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

2004-08-03T23:59:59.000Z

4

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

E-Print Network [OSTI]

to driveability problems) and on the fuel/air ratio (FAR) (leading to pollution peaks). To compensateMotion planning for experimental air path control of a variable-valve-timing spark ignition engine Syste´mes, Mines-ParisTech 60, bd St Michel, 75272 Paris, France a r t i c l e i n f o Article history

5

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

DOE Patents [OSTI]

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

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

1995-01-01T23:59:59.000Z

6

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

SciTech Connect (OSTI)

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

Bunting, Bruce G [ORNL

2006-01-01T23:59:59.000Z

7

Compact, electro-hydraulic, variable valve actuation system providing...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Compact, electro-hydraulic, variable valve actuation system providing variable lift, timing and duration to enable high efficiency engine combustion control Compact,...

8

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

DOE Patents [OSTI]

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

2013-07-02T23:59:59.000Z

9

Combustion Phasing Model for Control of a Gasoline-Ethanol Fueled SI Engine with Variable Valve Timing  

E-Print Network [OSTI]

Combustion Phasing Model for Control of a Gasoline-Ethanol Fueled SI Engine with Variable Valve engine efficiency. Fuel-flexible engines permit the increased use of ethanol-gasoline blends. Ethanol points across the engine operating range for four blends of gasoline and ethanol. I. INTRODUCTION Fuel

10

Diagnostic for two-mode variable valve activation device  

DOE Patents [OSTI]

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

Fedewa, Andrew M

2014-01-07T23:59:59.000Z

11

Turbo-generator control with variable valve actuation  

DOE Patents [OSTI]

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)

2011-02-22T23:59:59.000Z

12

Valve  

DOE Patents [OSTI]

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)

1980-01-01T23:59:59.000Z

13

Towards Real-Time and Memory Efficient Predictions of Valve States in Diesel Engines  

E-Print Network [OSTI]

Towards Real-Time and Memory Efficient Predictions of Valve States in Diesel Engines Philippe Komma T¨ubingen, Germany {philippe.komma, andreas.zell}@uni-tuebingen.de system for a diesel engine

Zell, Andreas

14

Variable residence time vortex combustor  

DOE Patents [OSTI]

A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.

Melconian, Jerry O. (76 Beaver Rd., Reading, MA 01867)

1987-01-01T23:59:59.000Z

15

Impact of Variable Valve Timing on Low Temperature Combustion...  

Broader source: Energy.gov (indexed) [DOE]

and Combustion Effects of VVA Ignition Temperature and Ignition Delay Soot Chemistry Combine effects with PCCI Extension of LTC Operation Summary Acknowledgements and...

16

Impact of Variable Valve Timing on Low Temperature Combustion | Department  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe U.S. Department-2023 Idaho4Fuel Consumption Solutionsof

17

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

E-Print Network [OSTI]

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

Qiu, Yihui

18

Depressurization valve  

DOE Patents [OSTI]

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.

Skoda, G.I.

1989-03-28T23:59:59.000Z

19

Safety valve  

DOE Patents [OSTI]

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)

1984-01-01T23:59:59.000Z

20

Mesofluidic two stage digital valve  

DOE Patents [OSTI]

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

2013-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

An electromechanical valve drive incorporating a nonlinear mechanical transformer  

E-Print Network [OSTI]

In traditional internal combustion engines, a camshaft acts on the valve stems to open and close the valves. Valve timing is fixed relative to piston position. On the other hand, if a valve is flexibly controlled by a ...

Chang, Woo Sok, 1964-

2003-01-01T23:59:59.000Z

22

ESTIMATED SIL LEVELS AND RISK COMPARISONS FOR RELIEF VALVES AS A FUNCTION OF TIME-IN-SERVICE  

SciTech Connect (OSTI)

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

Harris, S.

2012-03-26T23:59:59.000Z

23

Check valve  

DOE Patents [OSTI]

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); Garcia, Pablo (Stanford, CA)

1999-08-24T23:59:59.000Z

24

Check valve  

DOE Patents [OSTI]

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.

1999-08-24T23:59:59.000Z

25

Heart Valve Lesson Plan Biomedical Engineering  

E-Print Network [OSTI]

Heart Valve Lesson Plan Biomedical Engineering Objective · Introduce students to biomedical Learning Outcomes · Students will understand the role and function of heart valves. · Students will learn does a heart valve work? · Why do we need to replace heart valves? Time Required (Itemized) · Lecture

Provancher, William

26

Flow metering valve  

DOE Patents [OSTI]

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)

1985-01-01T23:59:59.000Z

27

Flow metering valve  

DOE Patents [OSTI]

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.

1983-11-03T23:59:59.000Z

28

Fast acting multiple element valve  

DOE Patents [OSTI]

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)

1991-01-01T23:59:59.000Z

29

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

E-Print Network [OSTI]

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

Qiu, Yihui

30

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

E-Print Network [OSTI]

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

Kassakian, John G.

31

Time resolved spectroscopy of the variable brown dwarf Kelu-1  

E-Print Network [OSTI]

We report the results of observations designed to investigate the spectroscopic signatures of dust clouds on the L2 brown dwarf Kelu-1. Time resolved medium resolution spectra show no significant evidence of variability in the dust sensitive TiO, CrH and FeH bandheads on the timescale of 1--24 hours. We do however report periodic variability in the psuedo-equivelent width of H-alpha consistent with the 1.8 hour rotation period previously reported for this object Clarke, Tinney & Tolley (2002). Near-contemporaneous I-band photometry shows evidence for non-periodic variability at the level of 2%.

F. J. Clarke; C. G. Tinney; S. T. Hodgkin

2003-01-09T23:59:59.000Z

32

Self-regulating valve  

DOE Patents [OSTI]

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.

1982-07-20T23:59:59.000Z

33

Nuclear radiation actuated valve  

DOE Patents [OSTI]

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); Schively, Dixon P. (Richland, WA)

1985-01-01T23:59:59.000Z

34

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

E-Print Network [OSTI]

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

Otten, James S. (James Stewart)

2006-01-01T23:59:59.000Z

35

Piezoelectric valve  

DOE Patents [OSTI]

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

2013-01-15T23:59:59.000Z

36

Thermostatic Radiator Valve Evaluation  

SciTech Connect (OSTI)

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

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

2015-01-01T23:59:59.000Z

37

Miniature piezo electric vacuum inlet valve  

DOE Patents [OSTI]

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.

1998-03-24T23:59:59.000Z

38

Miniature piezo electric vacuum inlet valve  

DOE Patents [OSTI]

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)

1998-03-24T23:59:59.000Z

39

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

DOE Patents [OSTI]

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

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

2012-04-17T23:59:59.000Z

40

Essays on Bayesian Time Series and Variable Selection  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 vi LIST OF FIGURES FIGURE Page 2.1 Dynamic Model. Given xt, yt is independent of y1:t?1, x1:t?1. . . . . . . 7 2.2 The figure shows estimated value of ? and ?2 from : (a)-(b) Stochastic Approximation approach; (c)-(d) Augmentation approach. In each... Sorenson (1970). 6 Let yt and xt be the p and q dimensional observation and hidden state variable at the time t. Let ? be set of unknown parameter. Figure (2.1) depicts the dynamic relation between yt and xt. The generalized version of state-space model can...

De, Debkumar

2014-05-08T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Artificial Heart Valve Design  

E-Print Network [OSTI]

Artificial Heart Valve Design Your Chance to be a Biomedical Engineer #12;Circulatory System Video #12;What is a Heart Valve? · Heart Valve Video #12;#12;What Does a Heart Valve Do? · Maintain the one direction flow of blood through the heart · Heart valves allow blood to flow through in a forward direction

Provancher, William

42

Valve for controlling solids flow  

DOE Patents [OSTI]

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)

1980-01-01T23:59:59.000Z

43

Remote actuated valve implant  

SciTech Connect (OSTI)

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

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

2014-02-25T23:59:59.000Z

44

Vacuum breaker valve assembly  

DOE Patents [OSTI]

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.

1999-04-27T23:59:59.000Z

45

Vacuum breaker valve assembly  

DOE Patents [OSTI]

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); Upton, Hubert Allen (Morgan Hill, CA)

1999-04-27T23:59:59.000Z

46

Valve for fluid control  

DOE Patents [OSTI]

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)

2001-01-01T23:59:59.000Z

47

Overflow control valve  

DOE Patents [OSTI]

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

1984-07-24T23:59:59.000Z

48

Managing transient behaviors of a dual mode spark ignition-- controlled auto ignition engine with a variable valve timing system  

E-Print Network [OSTI]

Gasoline Homogeneous Charge Compression Ignition (HCCI) engine has the potential of providing better fuel economy and emissions characteristics than current spark ignition engines. One implementation of this technology ...

Santoso, Halim G. (Halim Gustiono), 1975-

2005-01-01T23:59:59.000Z

49

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients  

E-Print Network [OSTI]

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period

Paris-Sud XI, Université de

50

Engine valve actuation for combustion enhancement  

DOE Patents [OSTI]

A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-strokes combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

Reitz, Rolf Deneys (Madison, WI); Rutland, Christopher J. (Madison, WI); Jhavar, Rahul (Madison, WI)

2008-03-04T23:59:59.000Z

51

Engine Valve Actuation For Combustion Enhancement  

DOE Patents [OSTI]

A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-stroke combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

Reitz, Rolf Deneys (Madison, WI); Rutland, Christopher J. (Madison, WI); Jhavar, Rahul (Madison, WI)

2004-05-18T23:59:59.000Z

52

Cycle time variability for a network under two queueing disciplines  

E-Print Network [OSTI]

the variance of those quantities. Conway (1965a and 1965b) and Rochette and Sadowski (1976) studied the FISFO dispatching rule. Conway studied a job shop that consisted of 9 machines and 8700 jobs per run in both studies. In the first article cited... in this thesis is a network comprised of three single-server queues. Two dispatching rules were implemented. The measures of performance were the mean and the variance of the cycle time. The following factors were used to analyze the performance of the FISFO...

Vasquez Pariente, Marta Irene

1996-01-01T23:59:59.000Z

53

VARIABILITY OF SOLAR RADIATION DATA OVER SHORT TIME INTERVALS Frank Vignola  

E-Print Network [OSTI]

VARIABILITY OF SOLAR RADIATION DATA OVER SHORT TIME INTERVALS Frank Vignola Department of Physics ra- diation. This article examines at the variability of beam and global solar radiation over short solar radiation values with ground-based data. 1. INTRODUCTION It is difficult to evaluate solar

Oregon, University of

54

Worstcase time bounds for MAXkSAT w.r.t. the number of variables  

E-Print Network [OSTI]

Worst­case time bounds for MAX­k­SAT w.r.t. the number of variables using local search #3; EDWARD A­trivial upper bounds w.r.t. the number of variables were known for MAX­SAT and MAX­2­SAT. An a for the exact solution of MAX­k­SAT / MAX­SAT. However, the exponential­time bounds obtained in this way are w.r

Hirsch, Edward A.

55

Energy Savings Potential of Process Control Valve Replacement  

E-Print Network [OSTI]

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

Holzenthal, L. Jr.

56

Multiscale simulations of the aortic heart valve : applications in disease and surgery  

E-Print Network [OSTI]

This thesis presents mathematical models describing the mechanical behavior of the human aortic heart valve over a range of length and time scales. In the human heart, the valves perform the vital function of controlling ...

Weinberg, Eli, 1979-

2008-01-01T23:59:59.000Z

57

Valve for gas centrifuges  

DOE Patents [OSTI]

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)

1984-01-01T23:59:59.000Z

58

Variable Camshaft Timing Engine Control A. G. Stefanopoulou, J. S. Freudenberg, J. W. Grizzle  

E-Print Network [OSTI]

| Multivariable Feedback Control, Air-to-Fuel Ratio, Emissions, Pollution Control, Internal Combustion Engines. I and Computer Science, University of Michigan an internal combustion engine to reduce feedgas emis- sions1 Variable Camshaft Timing Engine Control A. G. Stefanopoulou, J. S. Freudenberg, J. W. Grizzle

Stefanopoulou, Anna

59

Variable Camshaft Timing Engine Control A. G. Stefanopoulou, J. S. Freudenberg, J. W. Grizzle  

E-Print Network [OSTI]

| Multivariable Feedback Control, Air-to-Fuel Ratio, Emissions, Pollution Control, Internal Combustion Engines. I of Michigan an internal combustion engine to reduce feedgas emis- sions, regulate air-to-fuel ratio A. For the variable cam timing engine, issue i arises from the fact that minimization of feedgas emissions, smooth eng

Grizzle, Jessy W.

60

Fast closing valve  

DOE Patents [OSTI]

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)

1984-01-10T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Locking apparatus for gate valves  

DOE Patents [OSTI]

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)

1988-01-01T23:59:59.000Z

62

Valve stem and packing assembly  

DOE Patents [OSTI]

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.

1991-09-03T23:59:59.000Z

63

Valve stem and packing assembly  

DOE Patents [OSTI]

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)

1991-01-01T23:59:59.000Z

64

Reducing pressure loss of large diameter check valves  

SciTech Connect (OSTI)

Transcend Inc., a consulting firm that specializes in the use of computer simulation to optimize existing equipment and system designs, was approached by Mannesmann Demag AG, Moenchengladbach, Germany to optimize the design of its DRV-B check valve. In one of the first applications of Computational Fluid Dynamics (CFD) technology to valve design, the pressure loss coefficient (K) of the DRV-B valve was lowered to 0.40--0.50 for valve sizes NPS48--NPS12, the lowest possible level for this type of valve. The flow efficiency is three times better than that of the earlier design. As a result, the optimized Mannesmann Demag DRV-B check valve provides a dramatic reduction in operating cost, particularly in transmission service where natural gas is transported over long distances. The reduced pressure loss saves compressor fuel cost. For the optimized valve, the incremental compressor fuel cost is reduced to 1.5-times the capital cost of the valve calculated over a 20-year Life Cycle Cost (LCC) period.

NONE

1997-09-01T23:59:59.000Z

65

Long-Time Dynamics of Variable Coefficient mKdV Solitary Waves  

E-Print Network [OSTI]

We study the Korteweg-de Vries-type equation dt u=-dx(dx^2 u+f(u)-B(t,x)u), where B is a small and bounded, slowly varying function and f is a nonlinearity. Many variable coefficient KdV-type equations can be rescaled into this equation. We study the long time behaviour of solutions with initial conditions close to a stable, B=0 solitary wave. We prove that for long time intervals, such solutions have the form of the solitary wave, whose centre and scale evolve according to a certain dynamical law involving the function B(t,x), plus an H^1-small fluctuation.

S. I. Dejak; B. L. G. Jonsson

2005-03-08T23:59:59.000Z

66

Valve for gas centrifuges  

DOE Patents [OSTI]

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.

1982-03-17T23:59:59.000Z

67

Multi-port valve assembly  

DOE Patents [OSTI]

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)

1986-01-01T23:59:59.000Z

68

Micro-valve pump light valve display  

DOE Patents [OSTI]

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.

1993-01-19T23:59:59.000Z

69

Classification of heart valve condition using acoustic measurements  

SciTech Connect (OSTI)

Prosthetic heart valves and the many great strides in valve design have been responsible for extending the life spans of many people with serious heart conditions. Even though the prosthetic valves are extremely reliable, they are eventually susceptible to long-term fatigue and structural failure effects expected from mechanical devices operating over long periods of time. The purpose of our work is to classify the condition of in vivo Bjork-Shiley Convexo-Concave (BSCC) heart valves by processing acoustic measurements of heart valve sounds. The structural failures of interest for Bscc valves is called single leg separation (SLS). SLS can occur if the outlet strut cracks and separates from the main structure of the valve. We measure acoustic opening and closing sounds (waveforms) using high sensitivity contact microphones on the patient`s thorax. For our analysis, we focus our processing and classification efforts on the opening sounds because they yield direct information about outlet strut condition with minimal distortion caused by energy radiated from the valve disc.

Clark, G. [Lawrence Livermore National Lab., CA (United States)

1994-11-15T23:59:59.000Z

70

Fast-acting valve and uses thereof  

DOE Patents [OSTI]

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)

1982-01-01T23:59:59.000Z

71

Fast-acting valve and uses thereof  

DOE Patents [OSTI]

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.

1980-05-16T23:59:59.000Z

72

EVALUATION OF SPRING OPERATED RELIEF VALVE MAINTENANCE INTERVALS AND EXTENSION OF MAINTENANCE TIMES USING A WEIBULL ANALYSIS WITH MODIFIED BAYESIAN UPDATING  

SciTech Connect (OSTI)

The Savannah River Site (SRS) spring operated pressure relief valve (SORV) maintenance intervals were evaluated using an approach provided by the American Petroleum Institute (API RP 581) for risk-based inspection technology (RBI). In addition, the impact of extending the inspection schedule was evaluated using Monte Carlo Simulation (MCS). The API RP 581 approach is characterized as a Weibull analysis with modified Bayesian updating provided by SRS SORV proof testing experience. Initial Weibull parameter estimates were updated as per SRS's historical proof test records contained in the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD). The API RP 581 methodology was used to estimate the SORV's probability of failing on demand (PFD), and the annual expected risk. The API RP 581 methodology indicates that the current SRS maintenance plan is conservative. Cost savings may be attained in certain mild service applications that present low PFD and overall risk. Current practices are reviewed and recommendations are made for extending inspection intervals. The paper gives an illustration of the inspection costs versus the associated risks by using API RP 581 Risk Based Inspection (RBI) Technology. A cost effective maintenance frequency balancing both financial risk and inspection cost is demonstrated.

Harris, S.; Gross, R.; Mitchell, E.

2011-01-18T23:59:59.000Z

73

Operational experience using the novel FixCup collecting main valve  

SciTech Connect (OSTI)

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

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

1996-12-31T23:59:59.000Z

74

Semi-active compressor valve  

DOE Patents [OSTI]

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)

2010-07-27T23:59:59.000Z

75

Streamline coal slurry letdown valve  

DOE Patents [OSTI]

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.

1983-11-08T23:59:59.000Z

76

Internal combustion engine intake valve  

SciTech Connect (OSTI)

In a inlet valve for use in an internal combustion engine in which the valve has a stem and a head, the head having, when seated, a first side positioned within a combustion chamber of an engine block and a second, opposite, side attached to the stem, the second side including that piston of the head forming the seat with the engine block when the valve is in a seated position, and first side including that portion of the head from the seat toward the chamber when the valve is in the seated position, and the engine including means for moving the valve from the closed position to an open position to allow a fuel mixture to enter the chamber, the improvement in the valve comprising: an extension ridge from the first side, positioned in alignment with the periphery of the valve head, the ridge forming with the seat a single, continuous, smooth outer surface along the periphery thereof for reducing the coefficient of drag of the fuel entering the chamber around the valve head when the valve is in the open position.

Mosler, W.B.

1988-10-25T23:59:59.000Z

77

Running time variability and resource allocation : a data-driven analysis of high-frequency bus operations  

E-Print Network [OSTI]

Running time variability is one of the most important factors determining service quality and operating cost of high-frequency bus transit. This research aims to improve performance analysis tools currently used in the bus ...

Snchez-Martnez, Gabriel Eduardo

2013-01-01T23:59:59.000Z

78

Utility Accrual Real-Time Scheduling Under Variable Cost Functions Haisang Wu Umut Balli Binoy Ravindran E. Douglas Jensen  

E-Print Network [OSTI]

Utility Accrual Real-Time Scheduling Under Variable Cost Functions Haisang Wu Umut Balli Binoy,binoy}@vt.edu The MITRE Corporation Bedford, MA 01730, USA jensen@mitre.org Abstract We present a utility accrual real application activities that are subject to time/utility function time constraints, VCFs, and the multi

Ravindran, Binoy

79

All metal valve structure for gas systems  

DOE Patents [OSTI]

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

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

1984-11-13T23:59:59.000Z

80

The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature  

SciTech Connect (OSTI)

Natural nuclear reactors? Changes in the speed of light? If either of these concepts seem implausible to you now they certainly won't once Dr. Steve Lamoreaux (LANL) delivers his SLAC Colloquium lecture in the Panofsky Auditorium on November 7th at 4:15 pm entitled The Oklo Natural Reactor and the Time Variability of the Fundamental Constants of Nature. This lecture is a rare opportunity to learn not only about Oklo's incredible natural nuclear reactors but also to gain understanding about how the present-day study of these sites may alter our understanding of fundamental constants such as the speed of light. This event is a must-see for the curious!

Lamoreaux, Steve (LANL) [LANL

2005-11-07T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Surge-damping vacuum valve  

DOE Patents [OSTI]

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); Kelly, Benjamin E. (Tracy, CA)

1980-01-01T23:59:59.000Z

82

Software Enabled Virtually Variable Displacement Pumps -Theoretical and Experimental Studies  

E-Print Network [OSTI]

Software Enabled Virtually Variable Displacement Pumps - Theoretical and Experimental Studies the functional equivalent of a variable displacement pump. This approach combines a fixed displacement pump valve control, without many of the shortcomings of commercially available variable displacement pumps

Li, Perry Y.

83

Compact Radio Sources in Orion: New Detections, Time Variability, and Objects in OMC-1S  

E-Print Network [OSTI]

We present the analysis of four 3.6 cm radio continuum archival observations of Orion obtained using the Very Large Array in its A-configuration, with $0\\rlap.{''}3$ angular resolution. The observations were made during the period 1994-1997. In a region of $4' \\times 4'$, we detect a total of 77 compact radio sources. Of the total of detected sources, 54 are detected in one or more of the individual observations and 36 of these show time variability (by more than 30%) between the observed epochs. A deep image made from averaging all data shows an additional 23 faint sources, in the range of 0.1 to 0.3 mJy. Of the total of 77 sources, 39 are new centimeter detections. However, only 9 of the 77 sources do not have a previously reported counterpart at near-infrared, optical, or X-ray wavelengths. In particular, we detect three faint sources in the OMC-1S region that may be related to the sources that power the multiple outflows that emanate from this part of the Orion nebula. %We discuss the nature of these sources and its relation with the %near-infrared, optical, and X-ray objects in the region.

Luis A. Zapata; Luis F. Rodriguez; Stanley E. Kurtz; C. R. O'Dell

2004-03-15T23:59:59.000Z

84

Annular flow control safety valve  

SciTech Connect (OSTI)

A tubular housing having an inner tubular member forms an inner passageway inside of the inner member and an outer passageway between the inner member and the housing. The housing has valve openings leading from the outer passageway to the exterior of the housing and a tubular valve closure member telescopically moves on the interior of the housing. First means move the valve closure member in an upper direction for closing the openings and at least one actuating piston is telescopically movable within and has its longitudinal axis in the wall of the housing and engages the valve closure member. The piston is in communication with a hydraulic passageway adapted to extend to the well surface for actuating the closure member in a direction to open the valve openings. The closure member is positioned whereby upward flow through the outer passageway acts on the closure member to close the valve opening. At least one lockout piston telescopically moves within the housing and is actuated from the surface and is engageable with holding means in the housing for providing a hydraulic lockout for the valve. Shear means may be provided between the lockout piston and the housing for controlling the hydraulic lockout. A single seal is provided between the closure member and the housing and is positioned below the opening and exposed to the pressure on both sides when the valve is opened. Preferably the actuating pistons are connected to the valve closure member but the hydraulic lockout pistons engage but are unconnected to the valve closure member.

Black, P.W.; Pringle, R.E.

1981-06-16T23:59:59.000Z

85

Allocation of inventory to a variable, time-phased, on-line storage system under known demand  

E-Print Network [OSTI]

ALLOCATION OF INVENTORY TO A VARIABLE, TIME-PHASED, ON-LINE STORAGE SYSTEM UNDER KNOWN DEMAND A Thesis By CHARLES WESLEY WHITE Submitted to the Graduate College of the Texas ASM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE January, 1968 Major Subject: Industrial Engineering ALLOCATION OF INVENTORY TO A VARIABLE ~ T IME PHASED ~ ON L INE STORAGE SYSTEM UNDER KNOWN DEMAND A Thesis By CHARLES WESLEY WHITE Approved as to style...

White, Charles Wesley

1968-01-01T23:59:59.000Z

86

Cavitation guide for control valves  

SciTech Connect (OSTI)

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

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

1993-04-01T23:59:59.000Z

87

Heart valve tissue engineering Frank Baaijens  

E-Print Network [OSTI]

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

Stavroulakis, Georgios E.

88

CONTROL VALVE TESTING PROCEDURES AND EQUATIONS  

E-Print Network [OSTI]

a coefficient that is independent of valve size and constant for geometrically similar valves. However in the publication "Control Valve Flow Coefficients" by Rahmeyer and Driskell and published in the Pipeline Journal of ASCE. Testing Procedures The flow coefficient is experimentally determined for different valve openings

Rahmeyer, William J.

89

Multi-port valve  

DOE Patents [OSTI]

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.

1997-04-15T23:59:59.000Z

90

Multi-port valve  

DOE Patents [OSTI]

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)

1997-04-15T23:59:59.000Z

91

Valves - current operating experience of slurry valves (block and letdown) in coal liquefaction processes. Third quarter report  

SciTech Connect (OSTI)

This paper summarizes the recent letdown and block valve experience in the liquefaction pilot plants. Also included is a brief description of the research and development activities on valves which are conducted in supporting laboratories. The purpose of the summary is to concentrate on critical component problems common to all liquefaction plants, to avoid duplication of efforts, and to help provide timely solutions to the valve problems. The main source of information used in this paper is the Minutes of the Critical Component and Materials Meeting which is sponsored by the Office of Coal Processing, Fossil Energy, Department of Energy. Other sources of information such as the technical progress reports are also included based on availability and relevance to topics covered in this paper. It is intended that this report will be followed by updates as pertinent information concerning valves becomes available. In the subsequent sections of this paper a brief outline of past valve studies is given as background material followed by a summary of the most recent valve operating experience at the liquefaction plants.

NONE

1996-07-01T23:59:59.000Z

92

Annular flow diverter valve  

DOE Patents [OSTI]

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)

1980-01-01T23:59:59.000Z

93

Noninvasive valve monitor using alternating electromagnetic field  

DOE Patents [OSTI]

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); Haynes, Howard D. (Knoxville, TN); Casada, Donald A. (Knoxville, TN)

1993-01-01T23:59:59.000Z

94

Adaptive Robust Control of Programmable Valves with Manufacturer Supplied Flow Mapping Only  

E-Print Network [OSTI]

and final tracking accuracy. In addition, real-time adaptation is used to reduce the degree of modelling-in and meter-out orifices [2], [3], [4] through valves number 1,2 and 4,5; and ii) enabling the precise control is the significant modelling error. The cartridge valves are of fast response and low cost but low accuracy

Yao, Bin

95

Northern Hemisphere Modes of Variability and the Timing of Spring in Western North America  

E-Print Network [OSTI]

by controlling the number and intensity of warm days. There is also a regionwide trend in spring advancement to the atmosphere via carbon and water cycling (Schwartz 1992). Both phenoclimatic indicators (indices based in the biological world may be organized by certain modes of climate variability. If the state of these modes can

96

Active combustion flow modulation valve  

DOE Patents [OSTI]

A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

2013-09-24T23:59:59.000Z

97

American Valve: Order (2010-CW-1411)  

Broader source: Energy.gov [DOE]

DOE ordered American Valve, Inc. to pay a $5,000 civil penalty after finding American Valve had failed to certify that certain showerhead models comply with the applicable water conservation standards.

98

Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint  

SciTech Connect (OSTI)

This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.

Hodge, B. M.; Shedd, S.; Florita, A.

2012-08-01T23:59:59.000Z

99

Strategy for reducing the length and variability of aircraft lead time  

E-Print Network [OSTI]

Helicopter manufacturers typically build each aircraft to order, and the lead time for make or buy parts and assemblies can be several months or more. The manufacturers generally have a backlog of orders at any given time, ...

Bielat, Brendon (Brendon Michael)

2010-01-01T23:59:59.000Z

100

Fast-acting valve actuator  

DOE Patents [OSTI]

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)

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Lockout housing and sleeve for safety valve  

SciTech Connect (OSTI)

This patent describes apparatus for use in a subsurface valve. It comprises a lockout housing; and a lockout sleeve.

Dickson, R.L.; Davis, G.R.

1992-07-07T23:59:59.000Z

102

Pressure relief valve/safety relief valve testing  

SciTech Connect (OSTI)

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

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

1994-02-01T23:59:59.000Z

103

Valve for fuel pin loading system  

DOE Patents [OSTI]

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.

1984-01-01T23:59:59.000Z

104

Valve for fuel pin loading system  

DOE Patents [OSTI]

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)

1985-01-01T23:59:59.000Z

105

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

SciTech Connect (OSTI)

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.

1998-12-31T23:59:59.000Z

106

ON CONDITION MONITORING OF EXHAUST VALVES IN MARINE DIESEL ENGINES  

E-Print Network [OSTI]

with artificially in­ duced valve burn­through situations. The primary potential mon­ itoring measurements were engine performance. Further, during the expansion stroke at engine­builder specific timing, to lift its seat and thereby provide scavenge (from scavenge air system) of the polluted air in the cylinder

Mosegaard, Klaus

107

Valve assembly having remotely replaceable bearings  

DOE Patents [OSTI]

A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings.

Johnson, Evan R. (San Diego, CA); Tanner, David E. (Poway, CA)

1980-01-01T23:59:59.000Z

108

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

SciTech Connect (OSTI)

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

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

2014-01-01T23:59:59.000Z

109

First XMM-Newton observations of a Cataclysmic Variable I: Timing studies of OY Car  

E-Print Network [OSTI]

We present XMM-Newton observations of the eclipsing, disc accreting, cataclysmic variable OY Car which were obtained as part of the performance verification phase of the mission. The star was observed 4 days after an outburst and then again 5 weeks later when it was in a quiescent state. There is a quasi-stable modulation of the X-rays at ~2240 sec, which is most prominent at the lowest energies. We speculate that this may be related to the spin period of the white dwarf. The duration of the eclipse ingress and egress in X-rays is 20--30 sec. This indicates that the bulk of the X-ray emission originates from the boundary layer which has a negligible height above the surface of the white dwarf. The eclipse profile implies a white dwarf of mass M_{1}=0.9-1.1Msun and a secondary star of M_{2}=0.08-0.11Msun.

Gavin Ramsay; Tracey Poole; Keith Mason; France Cordova; William Priedhorsky; Alice Breeveld; Rudi Much; Julian Osborne; Dirk Pandel; Stephen Potter; Jennifer West; Peter Wheatley

2000-10-18T23:59:59.000Z

110

Sizing sliding gate valves for steam service  

SciTech Connect (OSTI)

Sliding gate valves have been used in thousands of applications during the past 40 yr. While steam control is a common application for these valves, thy are also used to control other gases and liquids. The sliding gate design provides straight-through flow, which minimizes turbulence, vibration, and noise. Seats are self-cleaning and self-lapping to provide a tight, long-lasting shutoff. A correctly sized valve is essential for accurate control. Valve size should be determined by service and system requirements, not by the size of the existing pipeline. Sizing a valve on the basis of pipeline size usually results in an oversized valve and poor control. Generally, regulator size is smaller than pipe size. Whenever complete information is known (inlet pressure, outlet pressure, or pressure drop, and required flow), determine the valve flow coefficient (C{sub v}) using the equations in ANSI/ISA S75.01 or a flow sizing chart. Tables of values for various types of valves are available from manufacturers. However, when complete system requirements are not known, valve oversizing is prevented by determining the design capacity of piping downstream from the valve. The valve should not be sized to pass more flow than the maximum amount the pipe can handle at a reasonable velocity. An example calculation is given.

Bollinger, R. [Jordan Value, Cincinnati, OH (United States)

1995-11-06T23:59:59.000Z

111

Evaluation of silicon-nitride ceramic valves.  

SciTech Connect (OSTI)

Silicon-nitride ceramic valves can improve the performance of both light- and heavy-duty automotive engines because of the superior material properties of silicon nitrides over current metal alloys. However, ceramics are brittle materials that may introduce uncertainties in the reliability and durability of ceramic valves. As a result, the lifetime of ceramic valves are difficult to predict theoretically due to wide variations in the type and distribution of microstructural flaws in the material. Nondestructive evaluation (NDE) methods are therefore required to assess the quality and reliability of these valves. Because ceramic materials are optically translucent and the strength-limiting flaws are normally located near the valve surface, a laser-scatter method can be used for NDE evaluation of ceramic valves. This paper reviews the progress in the development of this NDE method and its application to inspect silicon-nitride ceramic valves at various stages of manufacturing and bench and engine tests.

Sun, J. G.; Zhang, J. M.; Andrews, M. J.; Tretheway, J. S.; Phillips, N. S .L.; Jensen, J. A.; Nuclear Engineering Division; Univ. of Texas; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

112

Hydraulically actuated fuel injector including a pilot operated spool valve assembly and hydraulic system using same  

DOE Patents [OSTI]

The present invention relates to hydraulic systems including hydraulically actuated fuel injectors that have a pilot operated spool valve assembly. One class of hydraulically actuated fuel injectors includes a solenoid driven pilot valve that controls the initiation of the injection event. However, during cold start conditions, hydraulic fluid, typically engine lubricating oil, is particularly viscous and is often difficult to displace through the relatively small drain path that is defined past the pilot valve member. Because the spool valve typically responds slower than expected during cold start due to the difficulty in displacing the relatively viscous oil, accurate start of injection timing can be difficult to achieve. There also exists a greater difficulty in reaching the higher end of the cold operating speed range. Therefore, the present invention utilizes a fluid evacuation valve to aid in displacement of the relatively viscous oil during cold start conditions.

Shafer, Scott F. (Morton, IL)

2002-01-01T23:59:59.000Z

113

Dark Energy Model in Anisotropic Bianchi Type-III Space-Time with Variable EoS Parameter  

E-Print Network [OSTI]

A new dark energy model in anisotropic Bianchi type-III space-time with variable equation of state (EoS) parameter has been investigated in the present paper. To get the deterministic model, we consider that the expansion $\\theta$ in the model is proportional to the eigen value $\\sigma^{2}_{~2}$ of the shear tensor $\\sigma^{j}_~i$. The EoS parameter $\\omega$ is found to be time dependent and its existing range for this model is in good agreement with the recent observations of SNe Ia data (Knop et al. 2003) and SNe Ia data with CMBR anisotropy and galaxy clustering statistics (Tegmark et al. 2004). It has been suggested that the dark energy that explains the observed accelerating expansion of the universe may arise due to the contribution to the vacuum energy of the EoS in a time dependent background. Some physical aspects of dark energy model are also discussed.

Anirudh Pradhan; Hassan Amirhashchi

2010-10-12T23:59:59.000Z

114

E-Print Network 3.0 - absent pulmonary valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

assessment of leaflet deformation and mechanical properties Summary: has four heart valves; the aortic valve, the pulmonary valve, the mitral valve and the tricuspid...

115

Load Expansion of Stoichiometric HCCI Using Spark Assist and Hydraulic Valve Actuation  

SciTech Connect (OSTI)

A spark-assist homogeneous charge compression ignition (SA-HCCI) operating strategy is presented here that allows for stoichiometric combustion from 1000-3000 rpm, and at loads as high as 750 kPa net IMEP. A single cylinder gasoline engine equipped with direct fuel injection and fully variable hydraulic valve actuation (HVA) is used for this experimental study. The HVA system enables negative valve overlap (NVO) valve timing for hot internal EGR. Spark-assist stabilizes combustion over a wide range of engine speeds and loads, and allows for stoichiometric operation at all conditions. Characteristics of both spark-ignited combustion and HCCI are present, with combustion analysis showing a distinctive spark ignited phase of combustion, followed by a much more rapid HCCI combustion phase. At high load, the maximum pressure rise rate is controlled by a combination of spark timing and retarding the intake valve closing angle. The latter reduces the effective compression ratio, and therefore the compressive temperatures, allowing the high load limit of the operating range to be expanded. The SA-HCCI operating strategy exhibits improved thermal efficiency at most operating conditions, with fuel consumption improvements up to 9% realized at light engine loads. The SA-HCCI operating strategy presented here does not provide an efficiency advantage at all operating points compared to SI combustion; a decrease was observed at the highest speed and at loads above 500 kPa net IMEP. At light engine loads the majority of the heat release takes place during the HCCI phase of the heat release, and as such the NOx emissions are very low and are similar to levels observed in pure HCCI. At higher loads, a larger portion of the heat release takes place during the spark ignited phase of combustion, which produces NOx emissions that are much higher than is typically associated with HCCI, but still represent a decrease from conventional SI combustion. By limiting the fuel/air mixture to stoichiometric conditions, the higher NOx emissions do not represent an implementation barrier to this strategy because compatibility is maintained with very effective conventional 3-way catalysts.

Szybist, James P [ORNL; Nafziger, Eric J [ORNL

2010-01-01T23:59:59.000Z

116

FURTHER INVESTIGATION OF THE TIME DELAY, MAGNIFICATION RATIOS, AND VARIABILITY IN THE  

E-Print Network [OSTI]

with independent measurements carried out at the same epoch (Biggs et al. 1999), lending confidence in a confidence intervals that are somewhat larger than those of Biggs et al., probably because we adopt a more in relation to the lens mass model of Biggs et al., our best­fit time delay implies a Hubble constant of H o

Hewitt, Jacqueline H.

117

Model for inventory management in valve manufacturing cell at Waters Corporation  

E-Print Network [OSTI]

This thesis addresses the challenges of improving the on-time delivery performance of a high-volume critical part type in a high-product-mix manufacturing facility of valves. Preliminary analysis on the push-type production ...

Yao, Bingxin

2013-01-01T23:59:59.000Z

118

Observational constraints on models of the Universe with time variable Gravitational and Cosmological constants along MOG  

E-Print Network [OSTI]

The subject of this paper is to investigate the weak regime covariant scalar-tensor-vector gravity (STVG) theory, known as the MOdified gravity (MOG) theory of gravity. First, we show that the MOG in the absence of scalar fields is converted into $\\Lambda(t),G(t)$ models. Time evolution of the cosmological parameters for a family of viable models have been investigated. Numerical results with the cosmological data have been adjusted. We've introduced a model for dark energy (DE) density and cosmological constant which involves first order derivatives of Hubble parameter. To extend this model, correction terms including the gravitational constant are added. In our scenario, the cosmological constant is a function of time. To complete the model,interaction terms between dark energy and dark matter (DM) manually entered in phenomenological form. Instead of using the dust model for DM, we have proposed DM equivalent to a barotropic fluid. Time evolution of DM is a function of other cosmological parameters. Using sophisticated algorithms, the behavior of various quantities including the densities, Hubble parameter, etc. have been investigated graphically. The statefinder parameters have been used for the classification of DE models. Consistency of the numerical results with experimental data of $SneIa+BAO+CMB$ are studied by numerical analysis with high accuracy.

M. Khurshudyan; N. S. Mazhari; D. Momeni; R. Myrzakulov; M. Raza

2014-06-24T23:59:59.000Z

119

Miniature electrically operated diaphragm valve  

DOE Patents [OSTI]

The present invention provides a miniature electrically operated valve that can stand off significant pressures, that can be inexpensively produced, and that can be made to operate without continuous electrical power. A valve according to the present invention comprises a housing and a beam mounted with the housing. A diaphragm mounted with the housing forms a sealed fluid volume. An electromagnetic energy source, such as an electromagnetic coil, mounts with the housing and when energized urges the beam in one direction. The beam can be urged in the opposing direction by passive means or by reversing the polarity of the electromagnetic energy source or by a second electromagnetic energy source. Two fluid ports mount with the housing. A first fluid port mounts so that, as the beam is urged in one direction or the opposite, the beam urges the diaphragm to move between engaging and substantially sealing the fluid port and disengaging and not substantially sealing the fluid port. A seat can be mounted with the diaphragm to aid in sealing the fluid port. Latching mechanisms such as permanent magnets can be mounted so that the valve remains in the open or closed positions without continuous electrical power input. Fluid can flow through the housing between the two fluid ports when the diaphragm does not seal the first fluid port, but can be prevented from flowing by urging the beam so that the diaphragm seals the first fluid port. Various embodiments accommodate various latching mechanisms, electromagnetic energy sources, number of fluid ports, and diaphragm design considerations.

Adkins, Douglas R. (Albuquerque, NM); Spletzer, Barry L. (Albuquerque, NM); Wong, Chungnin C. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM); Fischer, Gary J. (Albuquerque, NM); Hesketh, Peter J. (Atlanta, GA)

2001-01-01T23:59:59.000Z

120

Valve assembly for use with high temperature and high pressure fluids  

DOE Patents [OSTI]

The valve assembly for use with high temperature and high pressure fluids has inner and outer spaced shells and a valve actuator support of inner and outer spaced members which are connected at their end portions to the inner and outer shells, respectively, to extend substantially normal to the longitudinal axis of the inner shell. A layer of resilient heat insulating material covers the outer surfaces of the inner shell and the inner actuator support member and is of a thickness to only occupy part of the spaces between the inner and outer shells and inner and outer actuator support members. The remaining portion of the space between the inner and outer shells and the space between the inner and outer members is substantially filled with a body of castable, rigid refractory material. A movable valve member is disposed in the inner shell. A valve actuator assembly is supported in the valve actuator support to extend into the inner shell for connection with the movable valve member for movement of the movable valve member to positions from a fully open to a fully closed position to control flow of fluid through the inner shell. An anchor mneans is disposed adjacent opposite sides of the axis of the valve actuator support and attached to the inner shell so that relative radial movement between the inner and outer shell is permitted by the layer of resilient heat insulating material and relative longitudinal movement of the inner shell to the outer shell is permitted in opposite directions from the anchor means to thereby maintain the functional integrity of the movable valve member by providing an area of the inner shell surrounding the movable valve member longitdinally stationary, but at the same time allowing radial movement.

De Feo, Angelo (Totowa, NY)

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Propellant actuated nuclear reactor steam depressurization valve  

DOE Patents [OSTI]

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

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

1992-01-01T23:59:59.000Z

122

Valve and dash-pot assembly  

DOE Patents [OSTI]

A dash-pot valve comprising a cylinder submerged in the fluid of a housing and having a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with tangentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

Chang, Shih-Chih (Richland, WA)

1986-01-01T23:59:59.000Z

123

Improved valve and dash-pot assembly  

DOE Patents [OSTI]

A dash-pot valve comprises a cylinder submerged in the fluid of a housing and have a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with targentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

Chang, S.C.

1985-04-23T23:59:59.000Z

124

Variability of a stellar corona on a time scale of days  

E-Print Network [OSTI]

Elemental abundance effects in active coronae have eluded our understanding for almost three decades, since the discovery of the First Ionization Potential (FIP) effect on the sun. The goal of this paper is to monitor the same coronal structures over a time interval of six days and resolve active regions on a stellar corona through rotational modulation. We report on four iso-phase X-ray spectroscopic observations of the RS CVn binary EI Eri with XMM-Newton, carried out approximately every two days, to match the rotation period of EI Eri. We present an analysis of the thermal and chemical structure of the Ei Eri corona as it evolves over the six days. Although the corona is rather steady in its temperature distribution, the emission measure and FIP bias both vary and seem to be correlated. An active region, predating the beginning of the campaign, repeatedly enters into our view at the same phase as it rotates from beyond the stellar limb. As a result, the abundances tend slightly, but consistently, to increa...

Nordon, Raanan; Drake, Stephen A

2012-01-01T23:59:59.000Z

125

ANALYSIS OF SAFETY RELIEF VALVE PROOF TEST DATA TO OPTIMIZE LIFECYCLE MAINTENANCE COSTS  

SciTech Connect (OSTI)

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

Gross, Robert; Harris, Stephen

2007-08-01T23:59:59.000Z

126

Michigan: General Motors Optimizes Engine Valve Technology |...  

Energy Savers [EERE]

has resulted in new engine valve technology on the 2014 Chevrolet Impala. EERE's Vehicle Technologies Office supported the research that led to this technical development...

127

Materials for Advanced Engine Valve Train  

Broader source: Energy.gov (indexed) [DOE]

275,000 * FY11 Funding - 225,000 Budget * Changes in internal combustion regimes * Materials properties of exhaust valves will need to change to accommodate higher temperatures...

128

American Valve: Proposed Penalty (2010-CW-1411)  

Broader source: Energy.gov [DOE]

DOE alleged in a Notice of Proposed Civil Penalty that American Valve, Inc. failed to certify a variety of showerheads as compliant with the applicable water conservation standards.

129

Hydraulic engine valve actuation system including independent feedback control  

DOE Patents [OSTI]

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

Marriott, Craig D

2013-06-04T23:59:59.000Z

130

D0 Silicon Upgrade: Control Dewar Valve Calculations  

SciTech Connect (OSTI)

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

Rucinski, Russ; /Fermilab

1995-10-20T23:59:59.000Z

131

THE COMPACT, TIME-VARIABLE RADIO SOURCE PROJECTED INSIDE W3(OH): EVIDENCE FOR A PHOTOEVAPORATED DISK?  

SciTech Connect (OSTI)

We present new Karl G. Jansky Very Large Array (VLA) observations of the compact ({approx}0.''05), time-variable radio source projected near the center of the ultracompact H II region W3(OH). The analysis of our new data as well as of VLA archival observations confirms the variability of the source on timescales of years and for a given epoch indicates a spectral index of {alpha} = 1.3 {+-} 0.3 (S{sub {nu}}{proportional_to}{nu}{sup {alpha}}). This spectral index and the brightness temperature of the source ({approx}6500 K) suggest that we are most likely detecting partially optically thick free-free radiation. The radio source is probably associated with the ionizing star of W3(OH), but an interpretation in terms of an ionized stellar wind fails because the detected flux densities are orders of magnitude larger than expected. We discuss several scenarios and tentatively propose that the radio emission could arise in a static ionized atmosphere around a fossil photoevaporated disk.

Dzib, Sergio A.; Rodriguez-Garza, Carolina B.; Rodriguez, Luis F.; Kurtz, Stan E.; Loinard, Laurent; Zapata, Luis A.; Lizano, Susana, E-mail: s.dzib@crya.unam.mx [Centro de Radiostronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia 58089 (Mexico)

2013-08-01T23:59:59.000Z

132

Cylinder valve packing nut studies  

SciTech Connect (OSTI)

The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31T23:59:59.000Z

133

Classification of heart valve sounds from experiments in an anechoic water tank  

SciTech Connect (OSTI)

In vivo studies in both sheep and humans were plagued by a number of problems including movement artifacts, biological noise, low signal-to-noise ratio (SNR), chest-wall reverberation, and limited bandwidth recordings as discussed by [1]. To overcome these problems it was decided to record heart valve sounds under controlled conditions deep in an anechoic water tank, free from reverberation noise. The main goal of this experiment was to obtain measurements of ''pure'' heart valve sounds free of the scattering effects of the body. Experiments were conducted at the Transdec facility in San Diego [2]. We used a high quality hydrophone together with a wide-band data acquisition system [2]. We recorded sounds from 100 repetitions of the opening-closing cycles on each of 50 different heart valves, including 21 SLS valves and 29 intact valves. The power spectrum of the opening and closing phases of each cycle were calculated and outlier spectra removed as described by Candy [2]. In this report, we discuss the results of our classification of the heart valve sound measurements. The goal of this classification task was to apply the fundamental classification algorithms developed for the clinical data in 1994 and 1996 to the measurements from the anechoic water tank. From the beginning of this project, LLNL's responsibility has been to process and classify the heart valve sounds. For this experiment, however, we processed both the opening sounds and closing sounds for comparison purposes. The results of this experiment show that the classifier did not perform well because of low signal-to-noise ratio and excessive variability in signal power from beat-to-beat for a given valve.

Axelrod, M C; Clark, G A; Scott, D

1999-06-01T23:59:59.000Z

134

Characterization of the mitral valve using accelerated wear testing.  

E-Print Network [OSTI]

??There is a fundamental need for a better kind of long-term testing for artificial heart valves along with a biologically equivalent artificial mitral valve. Accelerated (more)

Riggan, Courtney N.

2010-01-01T23:59:59.000Z

135

Requirements for the Valve Train and Technolgies for Enabling...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

for the Valve Train and Technolgies for Enabling HCCI over the Entire Operating Range Requirements for the Valve Train and Technolgies for Enabling HCCI over the Entire Operating...

136

High precision high flow range control valve  

DOE Patents [OSTI]

A fluid control valve is described having a valve housing having first and second valve housing openings for the ingress and egress of fluid through the control valve. Disposed within a void formed by the control valve is a sleeve having at least one sleeve opening to permit the flow of fluid therethrough. A flow restricter travels within the sleeve to progressively block off the sleeve opening and thereby control flow. A fluid passageway is formed between the first valve housing opening and the outer surface of the sleeve. A second fluid passageway is formed between the inside of the sleeve and the second valve housing opening. Neither fluid passageway contains more than one 90 [degree] turn. In the preferred embodiment only one of the two fluid passageways contains a 90[degree] turn. In another embodiment, the control valve housing is bifurcated by a control surface having control surface opening disposed therethrough. A flow restricter is in slidable contact with the control surface to restrict flow of fluid through the control surface openings. 12 figs.

McCray, J.A.

1999-07-13T23:59:59.000Z

137

High speed exhaust gas recirculation valve  

DOE Patents [OSTI]

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)

2005-01-18T23:59:59.000Z

138

Risk assessment of drain valve failure in the K-West basin south loadout pit  

SciTech Connect (OSTI)

The drain valve located in the bottom of the K-West Basin South Loadout Pit (SLOP) could provide an additional leak path from the K Basins if the drain valve were damaged during construction, installation, or operation of the cask loading system. For the K-West Basin SLOP the immersion pail support structure (IPSS) has already been installed, but the immersion pail has not been installed in the IPSS. The objective of this analysis is to evaluate the risk of damaging the drain valve during the remaining installation activities or operation of the cask loading system. Valve damage, as used in this analysis, does not necessarily imply large amounts of the water will be released quickly from the basin, rather valve damage implies that the valve's integrity has been compromised. The analysis process is a risk-based uncertainty analysis where best engineering judgement is used to represent each variable in the analysis. The uncertainty associated with each variable is represented by a probability distribution. The uncertainty is propagated through the analysis by Monte Carlo convolution techniques. The corresponding results are developed as a probability distribution and the risk is expressed in terms of the corresponding complementary cumulative distribution function (''risk curve''). The total risk is the area under the ''risk curve''. The risk of potentially dropping a cask into or on the IPSS and damaging the drain valve is approximately 1 x 10{sup -4} to 2 x 10{sup -5} per year. The risk of objects falling behind the IPSS and damaging the valve is 3 x 10{sup -2} to 6 x 10{sup -3} per year. Both risks are expressed as drain value failure frequencies. The risk of objects falling behind the IPSS and damaging the valve can be significantly reduced by an impact limiter and/or installing a gating or plate over the area bounded by the back of the IPSS and the wall of the SLOP. With either of these actions there is a 90 percent confidence that the frequency of drain valve failure would be less than 1 x 10{sup -6} per year.

MORGAN, R.G.

1999-06-23T23:59:59.000Z

139

Variable Speed Pumping for Level Control  

E-Print Network [OSTI]

The purpose of this paper is to describe an application of variable speed pumping to level control of an industrial process. Topics include a comparison of the process using control valves with a variable speed system, an energy savings and cost...

Vasel, M.

1982-01-01T23:59:59.000Z

140

Variable Cosmological Parameter and S-channel Quantum Matter Fields Hadamard renormalization in Spherically Symmetric Curved Space Times  

E-Print Network [OSTI]

Aim of the paper is to obtain 2d analogue of the backreaction equation which will be useful to study final state of quantum perturbed spherically symmetric curved space times. Thus we take Einstein-massless-scalar $\\psi$ tensor gravity model described on class of spherically symmetric curved space times. We rewrite the action functional in 2d analogue in terms of dimensionless dilaton-matter field $(\\chi=\\Phi\\psi)$ where dilaton field $\\Phi$ is conformal factor of 2-sphere. Then we seek renormalized expectation value of quantum dilaton-matter field stress tensor operator by applying Hadamard rennormalization prescription. Singularity of the Green function is assumed to be has logarithmic form. Covariantly conservation condition on the renormalized quantum dilaton-matter stress tensor demands to input a variable cosmological parameter $\\lambda(x)$. Energy conditions (weak, strong and null) is studied on the obtained renormalized stress tensor leading to dynamical equations for $\\lambda(x), \\Phi$ and quantum vacuum state $W_0(x)=_{ren}.$ In weak quantum field limits our obtained trace anomaly corresponds to one which obtained from zeta regularization. Setting null-like apparent horizon equation $\

Hossein Ghaffarnejad

2015-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

A systematic periodicity and time-variable modulation search in RXTE ASM data : methods, findings, and implications for astrophysical X-ray sources  

E-Print Network [OSTI]

In this work, we present the results of a general search for periodicities and for time-variable modulation strength in X-ray sources using data from the All-Sky Monitor onboard the Rossi X-ray Timing Explorer. New findings, ...

Harris, Robert J., S.M. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

142

Production-Intent Lost-Motion Variable Valve Actuation Systems...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

& Publications Expanding Robust HCCI Operation (Delphi CRADA) Rapid Compression Machine A Key Experimental Device to Effectively Collaborate with Basic Energy Sciences...

143

Compact, electro-hydraulic, variable valve actuation system providing  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartmentTieCelebrate Earth Codestheat Two AluminumWHAT:Energy1

144

Variable Valve Actuation for Advanced Mode Diesel Combustion | Department  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment of EnergyProgram2-26TheUtility-Scaleof Energy Stephen55of Energy

145

Pressure compensated flow control valve  

DOE Patents [OSTI]

The invention is an air flow control valve which is capable of maintaining a constant flow at the outlet despite changes in the inlet or outlet pressure. The device consists of a shell assembly with an inlet chamber and outlet chamber separated by a separation plate. The chambers are connected by an orifice. Also located within the inlet chamber is a port controller assembly. The port controller assembly consists of a differential pressure plate and port cap affixed thereon. The cap is able to slide in and out of the orifice separating the inlet and outlet chambers. When the pressure differential is sufficient, the differential pressure plate rises or falls to maintain a constant air flow. Movement of the port controller assembly does not require the use of seals, diaphragms, tight tolerances, bushings, bearings, hinges, guides, or lubricants.

Minteer, Daniel J. (West Richland, WA)

1999-01-01T23:59:59.000Z

146

Whitey SCHe Ball Valves Provide Test Port Isolation  

SciTech Connect (OSTI)

These valves are 1/4-inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as normally closed isolation valves for test ports in the SCHe System between the gage root valve and the pressure indicator.

MISKA, C.R.

2000-10-19T23:59:59.000Z

147

Valve Cap For An Electric Storage Cell  

DOE Patents [OSTI]

The valve cap for an electric storage cell includes a central annular valve seat (23) and a membrane (5) fixed by its peripheral edge and urged against the seat by a piston (10) bearing thereagainst by means of a spring (12), the rear end of said spring (12) bearing on the endwall (8) of a chamber (20) formed in the cap and containing the piston (10) and the spring. A vent (19) puts the chamber (20) into communication with the atmosphere. A central orifice (26, 28) through the piston (10) and the membrane (5), enables gas from within the cell to escape via the top vent (19) when the valve opens.

Verhoog, Roelof (Bordeaux, FR); Genton, Alain (Merignac, FR)

2000-04-18T23:59:59.000Z

148

Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating  

DOE Patents [OSTI]

A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization. 14 figs.

Casada, D.A.

1996-01-16T23:59:59.000Z

149

Method and apparatus for monitoring motor operated valve motor output torque and power at valve seating  

DOE Patents [OSTI]

A method and apparatus are provided for monitoring a motor operated valve during the brief period when the valve seats and the torque switch trips to deenergize the valve motor. The method uses voltage measurements on the load side of a deenergizing switch that opens to deenergize the motor to determine, among other things, final motor rotational speed and the decelerating torque at motor deenergization.

Casada, Donald A. (Oak Ridge, TN)

1996-01-01T23:59:59.000Z

150

Classification of heart valve sounds from experiments in an anechoic water tank  

SciTech Connect (OSTI)

In vivo studies in both sheep and humans were plagued by a number of problems including movement artifacts, biological noise, low signal-to-noise ratio (SNR), chest-wall reverberation, and limited bandwidth recordings as discussed by [1]. To overcome these problems it was decided to record heart valve sounds under controlled conditions deep in an anechoic water tank, free from reverberation noise, including surface reflections. Experiments were conducted in a deep water tank at the Transdec facility in San Diego, which satisfies these requirements. The Transdec measurements are free of reverberations, but not totally free of acoustic and electrical noise. We used a high quality hydrophone together with a wide-band data acquisition system [2]. We recorded sounds from 100 repetitions of the opening-closing cycles on each of 50 different heart valves, including 21 SLS valves and 29 intact valves. The power spectrum of the opening and closing phases of each cycle were calculated and outlier spectra removed as described by Candy [2]. In this report, we discuss the results of our classification of the heart valve sound measurements. The goal of this classification task was to apply the fundamental classification algorithms developed for the clinical data in 1994 and 1996 to the measurements from the anechoic water tank. From the beginning of this project, LLNL's responsibility has been to process and classify the heart valve opening sounds. For this experiment, however, we processed both the opening sounds and closing sounds for comparison purposes. The results of this experiment show that the classifier did not perform well. We believe this is because of low signal-to-noise ratio and excessive variability in signal power from beat-to-beat for a given valve.

Axelrod, M C; Clark, G A; Scott, D

1999-06-01T23:59:59.000Z

151

Valve studies: Hydrogen fluoride monitoring of UF{sub 6} cylinder valves  

SciTech Connect (OSTI)

Uranium hexafluoride (UF{sub 6}) cylinder valves have, like the cylinders, been in use and/or storage for periods ranging from 15 to 44 years. Visual inspection of the cylinders has shown that the extent of corrosion and the overall cylinder condition varies widely throughout the storage yards. One area of concern is the integrity of the cylinder valves. Visual inspection has found deposits which have been identified as radioactive material on or near the valves. These deposits suggest leakage of UF{sub 6} and may indicate valve degradation; however, these deposits may simply be residual material from cylinder filling operations.

Leedy, R.R.; Ellis, A.R.; Hoffmann, D.P.; Marsh, G.C. [and others

1996-08-01T23:59:59.000Z

152

Method for valve seating control for an electro-hydraulic engine valve  

DOE Patents [OSTI]

Valve lift in an internal combustion engine is controlled by an electro-hydraulic actuation mechanism including a selectively actuable hydraulic feedback circuit.

Sun, Zongxuan (Plymouth, MN)

2011-01-11T23:59:59.000Z

153

Frostless heat pump having thermal expansion valves  

DOE Patents [OSTI]

A heat pump system having an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant and further having a compressor, an interior heat exchanger, an exterior heat exchanger, a heat pump reversing valve, an accumulator, a thermal expansion valve having a remote sensing bulb disposed in heat transferable contact with the refrigerant piping section between said accumulator and said reversing valve, an outdoor temperature sensor, and a first means for heating said remote sensing bulb in response to said outdoor temperature sensor thereby opening said thermal expansion valve to raise suction pressure in order to mitigate defrosting of said exterior heat exchanger wherein said heat pump continues to operate in a heating mode.

Chen, Fang C. (Knoxville, TN); Mei, Viung C. (Oak Ridge, TN)

2002-10-22T23:59:59.000Z

154

Install Removable Insulation on Valves and Fittings  

SciTech Connect (OSTI)

This revised ITP tip sheet on installing removable insulation on valves and fittings provides how-to advice for improving the system using low-cost, proven practices and technologies.

Not Available

2006-01-01T23:59:59.000Z

155

The safety valve and climate policy  

E-Print Network [OSTI]

In discussions of a cap-and-trade system for implementation of Kyoto Protocol-type quantity targets, a "safety valve" was proposed where, by government sales of emissions permits at a fixed price, the marginal cost of the ...

Jacoby, Henry D.; Ellerman, A. Denny.

156

Project Development Specification for Valve Pit Manifold  

SciTech Connect (OSTI)

Establishes the performance, design development, and test requirements for the valve pit manifolds. The system engineering approach was used to develop this document in accordance with the guidelines laid out in the Systems Engineering Management Plan for Project W-314.

MCGREW, D.L.

2000-09-28T23:59:59.000Z

157

Self Contained Temperature Actuated Control Valves  

E-Print Network [OSTI]

There is a virtually unlimited potential for energy conservation by utilizing self contained temperature actuated valves. As steam costs soar it becomes more and more important to conserve feed stock dollars as well as the energy these dollars...

Pirkle, F.

1979-01-01T23:59:59.000Z

158

Well injection valve with retractable choke  

SciTech Connect (OSTI)

An injection valve is described for use in a well conduit consisting of: a housing having a bore, a valve closure member in the bore moving between open and closed positions, a flow tube telescopically movable in the housing for controlling the movement of the valve closure member, means for biasing the flow tube in a direction for allowing the valve closure member to move to the closed position, an expandable and contractible fluid restriction connected to the flow tube and extending into the bore for moving the flow tube to the open position in response to injection fluid, but allowing the passage of well tools through the valve, the restriction contractible in response to fluid flow, the restriction includes, segments movable into and out of the bore, and biasing means yieldably urging the segments into the bore, a no-go shoulder on the flow tube, and releasable lockout means between the flow tube and the housing for locking the flow tube and valve in the open position.

Pringle, R.E.

1986-07-22T23:59:59.000Z

159

Split Venturi, Axially-Rotated Valve  

DOE Patents [OSTI]

The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane.

Walrath, David E. (Laramie, WY); Lindberg, William R. (Laramie, WY); Burgess, Robert K. (Sheridan, WY)

2000-08-29T23:59:59.000Z

160

Flow Split Venturi, Axially-Rotated Valve  

SciTech Connect (OSTI)

The present invention provides an axially-rotated valve which permits increased flow rates and lower pressure drop (characterized by a lower loss coefficient) by using an axial eccentric split venturi with two portions where at least one portion is rotatable with respect to the other portion. The axially-rotated valve typically may be designed to avoid flow separation and/or cavitation at full flow under a variety of conditions. Similarly, the valve is designed, in some embodiments, to produce streamlined flow within the valve. An axially aligned outlet may also increase the flow efficiency. A typical cross section of the eccentric split venturi may be non-axisymmetric such as a semicircular cross section which may assist in both throttling capabilities and in maximum flow capacity using the design of the present invention. Such a design can include applications for freeze resistant axially-rotated valves and may be fully-opened and fully-closed in one-half of a complete rotation. An internal wide radius elbow typically connected to a rotatable portion of the eccentric venturi may assist in directing flow with lower friction losses. A valve actuator may actuate in an axial manner yet be uniquely located outside of the axial flow path to further reduce friction losses. A seal may be used between the two portions that may include a peripheral and diametrical seal in the same plane. A seal separator may increase the useful life of the seal between the fixed and rotatable portions.

Walrath, David E. (Laramie, WY); Lindberg, William R. (Laramie, WY); Burgess, Robert K. (Sheridan, WY); LaBelle, James (Murrieta, CA)

2000-02-22T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

E-Print Network 3.0 - adjustable gravitational valves Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

with a discussion of control valve calibration, optimization of control constants... valve recovery coefficient CG control valve gas sizing coefficient cV specific heat at...

162

A new measure of acceleration of heart rate: dependence on age and comparison with time domain conventional heart rate variability measures  

E-Print Network [OSTI]

A new measure of acceleration of heart rate: dependence on age and comparison with time domain conventional heart rate variability measures Giuseppe Germanò, M.D., Gianfranco Piccirillo, M.D., *Camillo We introduce a new index, Acceleration Ratio (AR), in order to investigate the dependence of Heart

Cammarota, Camillo

163

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES  

SciTech Connect (OSTI)

The work summarized here comprises the concluding effort of a multi-year project, funded by the U.S. Department of Energy, Office of Vehicle Technologies. It supports the development of a better understanding of advanced diesel engine designs in which enhanced power density, energy efficiency, and emissions control place increasing demands upon the durability of engine materials. Many kinds of metallic alloys are used in engines depending on the operating stresses, temperatures, and chemical environments. Exhaust valves, for example, are subjected to high temperatures and repetitive surface contacts that place demands on durability and frictional characteristics of the materials. Valves must continue to seal the combustion chamber properly for thousands of hours of cyclic engine operation and under varying operating conditions. It was the focus of this effort to understand the wear processes in the valve-seat area and to develop a model for the surface deformation and wear of that important interface. An annotated bibliography is provided to illustrate efforts to understand valve wear and to investigate the factors of engine operation that affect its severity and physical manifestation. The project for which this modeling effort was the final task, involved construction of a high-temperature repetitive impact test system as well as basic tribology studies of the combined processes of mechanical wear plus oxidation at elevated temperatures. Several publications resulted from this work, and are cited in this report. The materials selected for the experimental work were high-performance alloys based on nickel and cobalt. In some cases, engine-tested exhaust valves were made available for wear analysis and to ensure that the modes of surface damage produced in experiments were simulative of service. New, production-grade exhaust valves were also used to prepare test specimens for experimental work along with the other alloy samples. Wear analysis of valves and seats run for hundreds of hours in heavy-duty diesels provided insights into the kinds of complexity that the contact conditions in engines can produce, and suggested the physical basis for the current approach to modeling. The model presented here involves four terms, two representing the valve response and two for its mating seat material. The model's structure assumes that wear that takes place under a complex combination of plastic deformation, tangential shear, and oxidation. Tribolayers form, are removed, and may reform. Layer formation affects the friction forces in the interface, and in turn, the energy available to do work on the materials to cause wear. To provide friction data for the model at various temperatures, sliding contact experiments were conducted from 22 to 850 C in a pin-on-disk apparatus at ORNL. In order to account for the behavior of different materials and engine designs, parameters in all four terms of the model can be adjusted to account for wear-in and incubation periods before the dominant wear processes evolve to their steady-state rates. For example, the deformation rate is assumed to be maximum during the early stages of operation, and then, due to material work-hardening and the increase in nominal contact area (which reduces the load per unit area), decreases to a lower rate at long times. Conversely, the rate of abrasion increases with time or number of cycles due to the build-up of oxides and tribo-layers between contact surfaces. The competition between deformation and abrasion results in complex, non-linear behavior of material loss per cycle of operation. Furthermore, these factors are affected by valve design features, such as the angle of incline of the valve seat. Several modeling scenarios are presented to demonstrate how the wear profile versus number of cycles changes in response to: (a) different relative abrasion rates of the seat and valve materials, (b) the friction coefficient as a function of temperature, (c) the relative deformation contribution of valve and seat materials, and (d) an interruption in the dominant we

Blau, Peter Julian [ORNL

2009-11-01T23:59:59.000Z

164

Simulant Development for Hanford Tank Farms Double Valve Isolation (DVI) Valves Testing  

SciTech Connect (OSTI)

Leakage testing of a representative sample of the safety-significant isolation valves for Double Valve Isolation (DVI) in an environment that simulates the abrasive characteristics of the Hanford Tank Farms Waste Transfer System during waste feed delivery to the Waste Treatment and Immobilization Plant (WTP) is to be conducted. The testing will consist of periodic leak performed on the DVI valves after prescribed numbers of valve cycles (open and close) in a simulated environment representative of the abrasive properties of the waste and the Waste Transfer System. The valve operations include exposure to cycling conditions that include gravity drain and flush operation following slurry transfer. The simulant test will establish the performance characteristics and verify compliance with the Documented Safety Analysis. Proper simulant development is essential to ensure that the critical process streams characteristics are represented, National Research Council report Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges

Wells, Beric E.

2012-12-21T23:59:59.000Z

165

Effects of aging and service wear on main steam isolation valves and valve operators  

SciTech Connect (OSTI)

In recent years main steam isolation valve (MSIV operating problems have resulted in significant operational transients (e.g., spurious reactor trips, steam generator dry out, excessive valve seat leakage), increased cost, and decreased plant availability. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. A detailed review of historical failure data available through the Institute of Nuclear Power Operation`s Nuclear Plant Reliability Data System has been conducted for several types of MSIVs and valve operators for both boiling-water reactors and pressurized-water reactors. The focus of this review is on MSIV failures modes, actuator failure modes, consequences of failure on plant operations, method of failure detection, and major stressors affecting both valves and valve operators.

Clark, R.L. [Oak Ridge National Lab., TN (United States)

1996-03-01T23:59:59.000Z

166

High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback  

SciTech Connect (OSTI)

This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when they are opened. As a result of this effort, we have devised a new design and have filed for a patent on a method of control which is believed to overcome this problem. The engine we have been working with originally had a single camshaft which controlled both the intake and exhaust valves. Single cycle lift and timing control was demonstrated with this system. (3) Large eddy simulations and KIVA based simulations were used in conjunction with flow visualizations in an optical engine to study fuel air mixing. During this effort we have devised a metric for quantifying fuel distribution and it is described in several of our papers. (4) A control system has been developed to enable us to test the benefits of the various technologies. This system used is based on Opal-RT hardware and is being used in a current DOE sponsored program.

Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung

2007-12-31T23:59:59.000Z

167

Bypass valve and coolant flow controls for optimum temperatures in waste heat recovery systems  

DOE Patents [OSTI]

Implementing an optimized waste heat recovery system includes calculating a temperature and a rate of change in temperature of a heat exchanger of a waste heat recovery system, and predicting a temperature and a rate of change in temperature of a material flowing through a channel of the waste heat recovery system. Upon determining the rate of change in the temperature of the material is predicted to be higher than the rate of change in the temperature of the heat exchanger, the optimized waste heat recovery system calculates a valve position and timing for the channel that is configurable for achieving a rate of material flow that is determined to produce and maintain a defined threshold temperature of the heat exchanger, and actuates the valve according to the calculated valve position and calculated timing.

Meisner, Gregory P

2013-10-08T23:59:59.000Z

168

Novel design of a rotary valve using axiomatic design  

E-Print Network [OSTI]

Rotary valves have existed for millennia; and while they have developed tremendously since the first Roman valves, many of the same problems have persisted. The basic problems are caused by the coupling of functional ...

Peliks, Robert Bilgor

2005-01-01T23:59:59.000Z

169

Design and Implementation of Silicon Nitride Valves for Heavy...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

More Documents & Publications Durability of ACERT Engine Components Durability of ACERT Engine Components Advanced Materials for Lightweight Valve Train Components...

170

Analysis of Flow in Pilot Operated Safety and Relief Valve of Nuclear Reactor Coolant System  

SciTech Connect (OSTI)

When the POSRV equipped in a nuclear power plant opens in instant by a failure in coolant system of PWR, a moving shock wave generates, and propagates downstream of the valve, inducing a complicated unsteadiness. The moving shock wave may exert severe load to the structure. In this connection, a method of gradual opening of the valve is used to reduce the load acting on the wall at the downstream of the POSRV. In the present study, experiments and calculations are performed to investigate the detail unsteady flow at the various pipe units and the effect of valve opening time on the flow downstream of the valve. In calculation by using of air as working fluid, 2-dimensional, unsteady compressible Navier-Stokes equations are solved by finite volume method. It was found that when the incident shock wave passes through the pipe unit, it may experience diffraction, reflection and interaction with a vortex. Furthermore, the geometry of the pipe unit affects the reflection type of shock wave and changes the load acting on the wall of pipe unit. It was also turned out that the maximum force acting on the wall of the pipe unit becomes in order of T-junction, 108 deg. elbow and branch in magnitude, respectively. And, the results obtained that show that the rapid pressure rise due to the moving shock wave by instant POSRV valve opening is attenuated by employing the gradual opening. (authors)

Kwon, Soon-Bum; Lee, Dong-Won [Department of Mechanical Engineering, Kyungpook National University, 1370, Sankyuk-dong, Daegu 702-701 (Korea, Republic of); Kim, In-Goo; Ahn, Hyung-Joon; Kim, Hho-Jung [Korea Institute of Nuclear Safety, 19, Kusungdong, Yousungku, Daejon 305-338 (Korea, Republic of)

2004-07-01T23:59:59.000Z

171

"Non-Reflective" Boundary Design via Remote Sensing and PID Control Valve  

SciTech Connect (OSTI)

This paper develops the concept of a nonreflective (or semireflective) boundary condition using the combination of a remote sensor and a control system to modulate a relief valve. The essential idea is to sense the pressure change at a remote location and then to use the measured data to adjust the opening of an active control valve at the end of the line to eliminate or attenuate the wave reflections at the valve, thus controlling system transient pressures. This novel idea is shown here through numerical simulation to have considerable potential for transient protection. Using this model, wave reflections and resonance can be effectively eliminated for frictionless pipelines or initial no-flow conditions and can be better controlled in more realistic pipelines for a range of transient disturbances. In addition, the features of even-order harmonics and nonreflective boundary conditions during steady oscillation, obtained through time domain transient analysis, are verified by hydraulic impedance analysis in the frequency domain.

Zhang, Qin Fen [ORNL] [ORNL; Karney, Professor Byran W. [University of Toronto, Canada] [University of Toronto, Canada; Pejovic, Dr. Stanislav [University of Toronto, Canada] [University of Toronto, Canada

2011-01-01T23:59:59.000Z

172

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

E-Print Network [OSTI]

to controlling the air mass aspirated in the cylinder. Besides, it is also desired to reduce engine pollutantMOTION PLANNING CONTROL OF THE AIRPATH OF AN S.I. ENGINE WITH VALVE TIMING ACTUATORS T. Leroy , J, France Abstract: We address the control of the airpath of a turbocharged S.I. engine equipped

Boyer, Edmond

173

Heart Valve Disease James S. Gammie, MD  

E-Print Network [OSTI]

Heart Valve Disease James S. Gammie, MD Professor and Chief Division of Cardiac Surgery University USA Source: CDC #12;#12;CARDIOTHORACIC SURGEON: A SURGEON THAT TREATS HEART AND LUNG DISEASE #12;Valvular Heart Disease: Common and Under-diagnosed 0 2 4 6 8 10 12 14 18 - 44 45 - 54 55 - 64 65 - 74 > 75

Weber, David J.

174

OPTIMAL LOCATION OF ISOLATION VALVES IN WATER  

E-Print Network [OSTI]

CHAPTER 7 OPTIMAL LOCATION OF ISOLATION VALVES IN WATER DISTRIBUTION SYSTEMS: A RELIABILITY systems to serve expanding population centers. Both the adaptation of existing technologies in water supply systems account for the largest cost item in future maintenance budgets. The aging

Mays, Larry W.

175

Dynamic Testing of Check Valves William Rahmeyer  

E-Print Network [OSTI]

the web site http://www.engineering.usu.edu/Departments/cee/Faculty/rahm/check.html INTRODUCTION The twoDynamic Testing of Check Valves William Rahmeyer Professor of Civil and Environmental Engineering rahmeyer@fs.uwrl.usu.edu http://www.engineering.usu.edu/Departments/cee/Faculty/rahm/check.html #12

Rahmeyer, William J.

176

Disc valve for sampling erosive process streams  

DOE Patents [OSTI]

This is a patent for a disc-type, four-port sampling valve for service with erosive high temperature process streams. Inserts and liners of ..cap alpha..-silicon carbide respectively, in the faceplates and in the sampling cavities, limit erosion while providing lubricity for a smooth and precise operation. 1 fig.

Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

1984-08-16T23:59:59.000Z

177

Microfluidic Cell Electroporation Using a Mechanical Valve  

E-Print Network [OSTI]

Microfluidic Cell Electroporation Using a Mechanical Valve Jun Wang, M. Jane Stine, and Chang Lu Center, and Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907 A microfluidic of integrating electroporation as a unit operation in large- scale microfluidic systems with the increasing

Lu, Chang

178

NONLINEAR MAGNETIC LEVITATION OF AUTOMOTIVE ENGINE VALVES  

E-Print Network [OSTI]

NONLINEAR MAGNETIC LEVITATION OF AUTOMOTIVE ENGINE VALVES K. Peterson, J.W. Grizzle, and A.G. Stefanopoulou University of Michigan, Ann Arbor Abstract: Position regulation of a magnetic levitation the region of attraction. The effects of magnetic saturation are included in the model, and accounted

Grizzle, Jessy W.

179

Valve supporting arrangement of an internal combustion engine  

SciTech Connect (OSTI)

A supporting arrangement is described for a valve of an internal combustion engine having a valve stem portion, comprising a rigid member for supporting the stem portion of the valve for axial movement of the valve, a stamped or press-formed upper retainer connected to the upper portion of the valve stem, a lower annular retainer disposed on the rigid member and surrounding the valve stem, and a coil spring compressed between the upper and lower retainers to bias the valve in a direction to close the associated valve opening. The upper retainer has a substantially constant thickness throughout and comprises an annular collar portion having an essentially constant diameter along the length thereof with the diameter at least substantially equal to the inner diameter of the coil spring. The collar portion is coaxially disposed within an upper portion of the coil spring, an annular flange portion extending radially outwardly from the upper end of the collar portion and engaging with the upper end of the coil spring, and means for achieving a spline connection between the central portion of the retainer and the upper portion of the valve stem, and wherein the upper retainer is divided along a diameter into two identical elements which are disposed about the upper portion of the valve stem such that the radial pressure exerted by the coil spring operates to bias the identical elements into their respective positions operative to connect the upper retainer to the valve stem.

Hayashi, Y.

1986-05-27T23:59:59.000Z

180

Statistical Performance Evaluation Of Soft Seat Pressure Relief Valves  

SciTech Connect (OSTI)

Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.

Harris, Stephen P.; Gross, Robert E.

2013-03-26T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

On the ""early-time"" evolution of variables relevant to turbulence models for Rayleigh-Taylor instability  

SciTech Connect (OSTI)

We present our progress toward setting initial conditions in variable density turbulence models. In particular, we concentrate our efforts on the BHR turbulence model for turbulent Rayleigh-Taylor instability. Our approach is to predict profiles of relevant parameters before the fully turbulent regime and use them as initial conditions for the turbulence model. We use an idealized model of the mixing between two interpenetrating fluids to define the initial profiles for the turbulence model parameters. Velocities and volume fractions used in the idealized mixing model are obtained respectively from a set of ordinary differential equations modeling the growth of the Rayleigh-Taylor instability and from an idealization of the density profile in the mixing layer. A comparison between predicted initial profiles for the turbulence model parameters and initial profiles of the parameters obtained from low Atwood number three dimensional simulations show reasonable agreement.

Rollin, Bertrand [Los Alamos National Laboratory; Andrews, Malcolm J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

182

Hydraulically actuated gas exchange valve assembly and engine using same  

DOE Patents [OSTI]

An engine comprises a housing that defines a hollow piston cavity that is separated from a gas passage by a valve seat. The housing further defines a biasing hydraulic cavity and a control hydraulic cavity. A gas valve member is also included in the engine and is movable relative to the valve seat between an open position at which the hollow piston cavity is open to the gas passage and a closed position in which the hollow piston cavity is blocked from the gas passage. The gas valve member includes a ring mounted on a valve piece and a retainer positioned between the ring and the valve piece. A closing hydraulic surface is included on the gas valve member and is exposed to liquid pressure in the biasing hydraulic cavity.

Carroll, Thomas S. (Peoria, IL); Taylor, Gregory O. (Hinsdale, IL)

2002-09-03T23:59:59.000Z

183

Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda Atlantic  

E-Print Network [OSTI]

Atlantic Time-Series Study (BATS) site David M. Glover,1 Scott C. Doney,2 Arthur J. Mariano,3 Robert H errors, and unresolved three-dimensional effects [Glover and Doney, 1996; Glover et al., 1998]. The appro

184

Technical evaluation: 300 Area steam line valve accident  

SciTech Connect (OSTI)

On June 7, 1993, a journeyman power operator (JPO) was severely burned and later died as a result of the failure of a 6-in. valve that occurred when he attempted to open main steam supply (MSS) valve MSS-25 in the U-3 valve pit. The pit is located northwest of Building 331 in the 300 Area of the Hanford Site. Figure 1-1 shows a layout of the 300 Area steam piping system including the U-3 steam valve pit. Figure 1-2 shows a cutaway view of the approximately 10- by 13- by 16-ft-high valve pit with its various steam valves and connecting piping. Valve MSS-25, an 8-in. valve, is located at the bottom of the pit. The failed 6-in. valve was located at the top of the pit where it branched from the upper portion of the 8-in. line at the 8- by 8- by 6-in. tee and was then ``blanked off`` with a blind flange. The purpose of this technical evaluation was to determine the cause of the accident that led to the failure of the 6-in. valve. The probable cause for the 6-in. valve failure was determined by visual, nondestructive, and destructive examination of the failed valve and by metallurgical analysis of the fractured region of the valve. The cause of the accident was ultimately identified by correlating the observed failure mode to the most probable physical phenomenon. Thermal-hydraulic analyses, component stress analyses, and tests were performed to verify that the probable physical phenomenon could be reasonably expected to produce the failure in the valve that was observed.

Not Available

1993-08-01T23:59:59.000Z

185

Analysis of HFIR pressurizer pump overspeed transients and relief valve performance  

SciTech Connect (OSTI)

The pressurizer pump overspeed transients at the High Flux Isotope Reactor (HFIR) fall in the category of {open_quotes}increase in coolant inventory transients.{close_quotes} They are among the accident transients to be performed for Chapter 15 of the HFIR safety analysis report (SAR). The pressurizer pump speed starting to increase inadvertently to reach its maximum speed of 3,560 rpm while the reactor operates under normal conditions is the cause of this transient. Increased primary coolant system pressure due to increased pressurizer pump flow into the primary coolant head tank challenges the relief valves to open. If the relief valves do not open, increased primary coolant system pressure will challenge the integrity of the high pressure boundary. Two sets of analyses were performed to analyze the pressurizer pump overspeed transients. The purpose of the first analysis is to estimate how long it will take for the relief valves to open under different conditions and whether or not they will chatter or flutter for a considerable amount of time. The analysis estimates relief valve performance and stability using four different relief valve subsystem models. The relief valve subsystem models are not attached to the primary coolant system model. Vigorous pressure oscillations were produced in all of the computations performed as part of the first analysis. The second analysis includes new simulations of the pressurizer pump overspeed transients that were previously simulated using the RELAP5 thermal-hydraulic computer code. The HFIRSYS, High Flux Isotope Reactor System Transient Analysis computer code, was utilized for these simulations providing referable results for comparisons. The increased pressurizer pump flow due to runaway pressurizer pump speed pressurizes the primary coolant system. The assumptions were made in such a way to form constraining conditions at initiation of and during the transients to generate as high an overpressure situation as possible.

Sozer, M.C.

1992-09-11T23:59:59.000Z

186

Micro-phytoplankton variability at the equatorial Pacific (140W?) during the JGOFS EQPAC Time Series Studies 1992  

E-Print Network [OSTI]

Micro-phytoplankton (>20 gm cell size) was sampled in the upper 200 m of the water column at the Pacific equator, 140'W, during two JGOFS EqPac Time Series Studies, in order to determine the changes in the micro-phytoplanlcton assemblage between...

Iriarte, Jose Luis

1994-01-01T23:59:59.000Z

187

Scoping Study on the Safety Impact of Valve Spacing in Natural Gas Pipelines  

SciTech Connect (OSTI)

The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is responsible for ensuring the safe, reliable, and environmentally sound operation of the nation's natural gas and hazardous liquid pipelines. Regulations adopted by PHMSA for gas pipelines are provided in 49 CFR 192, and spacing requirements for valves in gas transmission pipelines are presented in 49 CFR 192.179. The present report describes the findings of a scoping study conducted by Oak Ridge National Laboratory (ORNL) to assist PHMSA in assessing the safety impact of system valve spacing. Calculations of the pressures, temperatures, and flow velocities during a set of representative pipe depressurization transients were carried out using a one-dimensional numerical model with either ideal gas or real gas properties for the fluid. With both ideal gas and real gas properties, the high-consequence area radius for any resulting fire as defined by Stevens in GRI-00/0189 was evaluated as one measure of the pipeline safety. In the real gas case, a model for convective heat transfer from the pipe wall is included to assess the potential for shut-off valve failures due to excessively low temperatures resulting from depressurization cooling of the pipe. A discussion is also provided of some additional factors by which system valve spacing could affect overall pipeline safety. The following conclusions can be drawn from this work: (1) Using an adaptation of the Stephens hazard radius criteria, valve spacing has a negligible influence on natural gas pipeline safety for the pipeline diameter, pressure range, and valve spacings considered in this study. (2) Over the first 30 s of the transient, pipeline pressure has a far greater effect on the hazard radius calculated with the Stephens criteria than any variations in the transient flow decay profile and the average discharge rate. (3) Other factors besides the Stephens criteria, such as the longer burn time for an accidental fire, greater period of danger to emergency personnel, increased unavoidable loss of gas, and possible depressurization cooling of the shut-off valves may also be important when deciding whether a change in the required valve spacing would be beneficial from a safety standpoint. (4) The average normalized discharge rate of {lambda}{sub avg} = 0.33 assumed by Stephens in developing his safety criteria is an excellent conservative value for natural gas discharge at the pressures, valve spacings, and pipe diameter used in this study. This conclusion remains valid even when real rather than ideal gas properties are considered in the analysis. (5) Significant pipe wall cooling effects (T{sub w} < -50 F or 228 K) can extend for a mile or more upstream from the rupture point within 30 s of a break. These conditions are colder than the temperature range specifications for many valve lubricants. The length of the low-temperature zone due to this cooling effect is also essentially independent of the system shut-off valve spacing or the distance between the break and a compressor station. (6) Having more redundant shut-off valves available would reduce the probability that pipe cooling effects could interfere with isolating the broken area following a pipeline rupture accident.

Sulfredge, Charles David [ORNL

2007-07-01T23:59:59.000Z

188

Curved butterfly bileaflet prosthetic cardiac valve  

DOE Patents [OSTI]

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

McQueen, David M. (185 Hillside Ave., Chatham, NJ 07928); Peskin, Charles S. (186 Harrard Dr., Hartsdale, NY 10530)

1991-06-25T23:59:59.000Z

189

Are subsurface safety valves needed in deepwater?  

SciTech Connect (OSTI)

The object of this study was to evaluate SCSSV reliability and identify a preferred configuration for subsea completions in deepwater. A system design consisting of subsea, conventional, dual-bore tree, cluster wells was selected for evaluation. The study examined inherent risks associated with six tubing retrievable SCSSV configurations. Risks were evaluated for personnel and environmental safety, and operational and financial impact of: No SCSSV; Single SCSSV; Dual operating system single SCSSV; Tandem hot/hot (both valves active) SCSSVs without lockout features; Tandem hot/hot SCSSVs with lockout features; Tandem hot/cold (one valve active, the other dormant in open position) SCSSVs with lockout features. A ``fault tree`` identifying events that could lead to deleterious incidents was used to evaluate risks. Costs and consequences associated with potential events were determined using existing industry data, and resulting calculated risks were evaluated. Recommendations were developed and compared to current regulations, and potential regulatory conflicts were identified.

Verret, A.; Hey, C.

1995-11-01T23:59:59.000Z

190

Water cooling of HVDC thyristor valves  

SciTech Connect (OSTI)

It is generally accepted that water is a very effective medium to remove heat losses from any type of equipment. When used for HVDC thyristor valves, the fundamentals of electrolyte conduction and water chemistry need to be considered in the design of the cooling circuit. The characteristics of the materials used, in conjunction with high voltage stresses and circuit configuration, play an important role to assure longevity and corrosion-free performance.

Lips, H.P. (Siemens AG, Erlangen (Germany))

1994-10-01T23:59:59.000Z

191

Method and system for measuring gate valve clearances and seating force  

DOE Patents [OSTI]

Valve clearances and seating force, as well as other valve operational parameters, are determined by measuring valve stem rotation during opening and closing operations of a translatable gate valve. The magnitude of the stem rotation, and the relative difference between the stem rotation on opening and closing provides valuable data on the valve internals in a non-intrusive manner.

Casada, Donald A. (Knoxville, TN); Haynes, Howard D. (Knoxville, TN); Moyers, John C. (Oak Ridge, TN); Stewart, Brian K. (Burns, TN)

1996-01-01T23:59:59.000Z

192

Novel 4-Way Refrigerant Reversing Valve for Heat Pumps  

SciTech Connect (OSTI)

This project is nearing completion. Since the last progress report (November, 1999), all experimental tests have been completed. Preliminary analysis shows the refrigerant pressure drops through the reversing valve were reduced by an average of about 60{percent}, when compared to traditional reversing valves. Also, the prototype reversing valve reduced the overall coefficient of performance (COP) by an average of only 0.45{percent}.

Darin W. Nutter

2000-02-17T23:59:59.000Z

193

Design and production of a hermetic bayonet isolation valve  

SciTech Connect (OSTI)

Fermilab is upgrading the Tevatron for lower temperature/higher beam energy operation. Portions of the satellite refrigeration system will operate below atmospheric pressure after the upgrade is complete. Contamination must be prevented by hermetically sealing the subatmospheric helium to air interfaces. Bayonet connections in the low pressure flow path require a reliable, leak tight isolation valve instead of the standard quarter turn ball valve. Design, development, and production of a new valve are described.

Fuerst, J.

1993-05-01T23:59:59.000Z

194

Hydrodynamic injection with pneumatic valving for microchip electrophoresis with total analyte utilization  

SciTech Connect (OSTI)

A novel hydrodynamic injector that is directly controlled by a pneumatic valve has been developed for reproducible microchip capillary electrophoresis (CE) separations. The poly(dimethylsiloxane) (PDMS) devices used for evaluation comprise a separation channel, a side channel for sample introduction, and a pneumatic valve aligned at the intersection of the channels. A low pressure (? 3 psi) applied to the sample reservoir is sufficient to drive sample into the separation channel. The rapidly actuated pneumatic valve enables injection of discrete sample plugs as small as ~100 pL for CE separation. The injection volume can be easily controlled by adjusting the intersection geometry, the solution back pressure and the valve actuation time. Sample injection could be reliably operated at different frequencies (< 0.1 Hz to >2 Hz) with good reproducibility (peak height relative standard deviation ? 3.6%) and no sampling biases associated with the conventional electrokinetic injections. The separation channel was dynamically coated with a cationic polymer, and FITC-labeled amino acids were employed to evaluate the CE separation. Highly efficient (? 7.0 103 theoretical plates for the ~2.4 cm long channel) and reproducible CE separations were obtained. The demonstrated method has numerous advantages compared with the conventional techniques, including repeatable and unbiased injections, no sample waste, high duty cycle, controllable injected sample volume, and fewer electrodes with no need for voltage switching. The prospects of implementing this injection method for coupling multidimensional separations, for multiplexing CE separations and for sample-limited bioanalyses are discussed.

Sun, Xuefei; Kelly, Ryan T.; Danielson, William F.; Agrawal, Nitin; Tang, Keqi; Smith, Richard D.

2011-04-26T23:59:59.000Z

195

Subsurface safety valve with lock-open system  

SciTech Connect (OSTI)

A well safety valve is described comprising: a housing having a bore therethrough; a valve mounted in the housing to open and close to control the flow through the bore; an operator tube in the housing for opening the valve; means in the housing for moving the operator tube in a first direction to open and hold the valve open; means in the housing for moving the operator tube in a second direction to permit the valve to close; a temporary lockout sleeve in the housing in tandem with the operator tube for temporarily holding the valve open. The operator tube and the lockout sleeve are in end-to-end contact when the lockout sleeve is inoperative and the operator tube is holding the valve open, when the operator tube and the lockout sleeve are moving simultaneously in the housing between operating positions, and when the operator tube is inoperative and the lockout sleeve is holding the valve open; and the operator tube and the lockout sleeve each having means for coupling the operator tube and the lockout sleeve with a lockout tool for moving the operator tube and the lockout sleeve simultaneously when the lockout sleeve is moved from the inoperative to an operative position holding the valve open.

Dickson, R.L.; Smith, R.R.

1986-11-25T23:59:59.000Z

196

aortic valve leaflet: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diastolic diameter. The PDC Papaharilaou, Yannis 245 IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ONOFF VALVE ? CiteSeer Summary: A key enabling technology to...

197

aortic valve leaflets: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diastolic diameter. The PDC Papaharilaou, Yannis 245 IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ONOFF VALVE ? CiteSeer Summary: A key enabling technology to...

198

aortic valve stenosis: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

diastolic diameter. The PDC Papaharilaou, Yannis 233 IMECE2007-42559 HIGH SPEED ROTARY PULSE WIDTH MODULATED ONOFF VALVE ? CiteSeer Summary: A key enabling technology to...

199

ahmed valve device: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

increased control in the device. Some existing micro-pumps and valves utilized in microfluidics involve electrical, pneumatic, and thermal actuation. However, electrical...

200

Flexible semi-transparent organic spin valve based on bathocuproine  

SciTech Connect (OSTI)

Organic semiconductors are attractive materials for advanced spintronic applications due to their long spin lifetimes and, simultaneously, their mechanical flexibility. With the aim of combining these advantages in a single device, we report on the fabrication and properties of a mechanically flexible bathocuproine-based spin valve. This organic spin device shows great stability on both electrical and magneto-transport properties upon mechanical bending at different radius (up to r?=?5?mm), while featuring long-lasting endurance (on bending over 50 times). The room-temperature magnetoresistance ratio reaches up to 3.5%, and is notably preserved under air atmosphere. The observation of spin transport at room-temperature, combined with the outstanding mechanical properties and air stability, highlights the potential of bathocuproine-based spin devices towards applications.

Sun, Xiangnan; Bedoya-Pinto, Amilcar; Llopis, Roger [CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia San Sebastian (Spain); Casanova, Flix; Hueso, Luis E., E-mail: l.hueso@nanogune.eu [CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

2014-08-25T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

MS17AM LEAK CHECKER The MS17AM is a manual valve version of the MS17AB. Since it is a manual unit, some care must be  

E-Print Network [OSTI]

. A gurgling sound will be heard, caused by the high pressure air being exhausted from the pump. 5 minutes (time needed for diffusion pump to heat up), turn on the ELECTRONICS switch. Turning from a total shut down. a. Position of Valves and Control Switches Rough Pump.......Off Rough Valve

Massey, Thomas N.

202

Numerical Investigation of the Performance of Three Hinge Designs of Bileaflet Mechanical Heart Valves  

E-Print Network [OSTI]

parameters on bilea?et mechanical heart valve ?ow dynamics.J. Heart Valve Dis. 18:535545, 2009. Gross, J. M. , M. C.two bilea?et mechanical heart valves under aortic and mitral

Simon, Hlne A.; Ge, Liang; Sotiropoulos, Fotis; Yoganathan, Ajit P.

2010-01-01T23:59:59.000Z

203

E-Print Network 3.0 - air operated valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

.5 mm in dia- meter. To create an inlet for air into the pneumatic valve, we used polyethylene tubing... the pneumatic valve, we connected the tubing of the valve ... Source:...

204

System and method for controlling engine knock using electro-hydraulic valve actuation  

DOE Patents [OSTI]

A control system for an engine includes a knock control module and a valve control module. The knock control module adjusts a period that one or more of an intake valve and an exhaust valve of a cylinder are open based on engine knock corresponding to the cylinder. The valve control module, based on the adjusted period, controls the one or more of the intake valve and the exhaust valve using one or more hydraulic actuators.

Brennan, Daniel G

2013-12-10T23:59:59.000Z

205

Corrosion in HVDC valve cooling systems  

SciTech Connect (OSTI)

Stainless steel couplings in the main cooling water pipes of HVDC thyristor valves have been in use since 1983, with an overall satisfactory behavior. However, some water leakage due to corrosion below the sealing O-rings of the couplings was observed during 1992. An extensive investigation and follow-up worldwide showed a direct correlation between water quality and the corrosion rate of the stainless steel couplings. Recommendations are given about actions to be taken in order to maintain a long lifetime for the fine water systems.

Jackson, P.O.; Abrahamsson, B.; Gustavsson, D.; Igetoft, L.

1997-04-01T23:59:59.000Z

206

Nuclear-radiation-actuated valve. [Patent application; for increasing coolant flow to blanket  

DOE Patents [OSTI]

The present invention relates to a breeder reactor blanket fuel assembly coolant system valve which increases coolant flow to the blanket fuel assembly to minimize long-term temperature increases caused by fission of fissile fuel created from fertile fuel through operation of the breeder 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, D.W.; Schively, D.P.

1982-01-19T23:59:59.000Z

207

E-Print Network 3.0 - aortic valve bioprosthesis Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Biomechanics 34 (2001) 12791289 A nonlinear anisotropic model for porcine aortic heart valves Summary: of porcine aortic valve leaflet has potentially significant effects on...

208

E-Print Network 3.0 - aortic valve insufficiency Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

insufficiency Page: << < 1 2 3 4 5 > >> 1 Interaction between the mitral and aortic heart valve Summary: Interaction between the mitral and aortic heart valve an experimental...

209

E-Print Network 3.0 - aortic valve reconstruction Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

reconstruction Page: << < 1 2 3 4 5 > >> 1 Interaction between the mitral and aortic heart valve Summary: Interaction between the mitral and aortic heart valve an experimental...

210

E-Print Network 3.0 - aortic disc valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Hannover Collection: Biology and Medicine 2 Interaction between the mitral and aortic heart valve Summary: Interaction between the mitral and aortic heart valve an experimental...

211

E-Print Network 3.0 - aortic valve prostheses Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

... Source: Collection: Engineering 2 Interaction between the mitral and aortic heart valve Summary: and aortic valve prostheses as well as give directions for improvement...

212

E-Print Network 3.0 - aortic valve morphology Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Toronto Collection: Engineering ; Biology and Medicine 2 Mechanobiology of the Aortic Heart Valve Jonathan T. Butcher1 Summary: Review: Mechanobiology of the Aortic Heart Valve...

213

E-Print Network 3.0 - aortic valve interstitial Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Toronto Collection: Engineering ; Biology and Medicine 2 Mechanobiology of the Aortic Heart Valve Jonathan T. Butcher1 Summary: Review: Mechanobiology of the Aortic Heart Valve...

214

Nonlinear Control for Magnetic Levitation of Automotive Engine Valves  

E-Print Network [OSTI]

1 Nonlinear Control for Magnetic Levitation of Automotive Engine Valves Katherine Peterson, Member of a magnetic levitation device is achieved through a control Lyapunov function (CLF) feedback design for and implemented on an electromagnetic valve actuator for use in automotive engines, the control methodology

Grizzle, Jessy W.

215

Analysis of Cardiac Micro-Acceleration Signals for the Estimation of Systolic and Diastolic Time Intervals in Cardiac Resynchronization Therapy  

E-Print Network [OSTI]

error and coefficient stability. Models for mitral valve closing, aor- tic valve closing and opening, fitted between CMA features and echo timings, were eval- uated with their correlation coefficient, model instants showed satisfactory results, whereas the estimation of the opening instant of the mitral valve

Boyer, Edmond

216

Advanced modeling ,control, and design of an electromechanical engine value drive system with a limited-angle actuator  

E-Print Network [OSTI]

This thesis addresses a specific variable valve actuation (VVA) system ---- an electromechanical valvetrain ---- in order to provide variable valve timing (VVT) in internal combustion (IC) engines. This electromechanical ...

Qiu, Yihui, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

217

Negative Valve Overlap Reforming Chemistry in Low-Oxygen Environments  

SciTech Connect (OSTI)

Fuel injection into the negative valve overlap (NVO) period is a common method for controlling combustion phasing in homogeneous charge compression ignition (HCCI) and other forms of advanced combustion. When fuel is injected into O2-deficient NVO conditions, a portion of the fuel can be converted to products containing significant levels of H2 and CO. Additionally, other short chain hydrocarbons are produced by means of thermal cracking, water-gas shift, and partial oxidation reactions. The present study experimentally investigates the fuel reforming chemistry that occurs during NVO. To this end, two very different experimental facilities are utilized and their results are compared. One facility is located at Oak Ridge National Laboratory, which uses a custom research engine cycle developed to isolate the NVO event from main combustion, allowing a steady stream of NVO reformate to be exhausted from the engine and chemically analyzed. The other experimental facility, located at Sandia National Laboratories, uses a dump valve to capture the exhaust from a single NVO event for analysis. Results from the two experiments are in excellent trend-wise agreement and indicate that the reforming process under low-O2 conditions produces substantial concentrations of H2, CO, methane, and other short-chain hydrocarbon species. The concentration of these species is found to be strongly dependent on fuel injection timing and injected fuel type, with weaker dependencies on NVO duration and initial temperature, indicating that NVO reforming is kinetically slow. Further, NVO reforming does not require a large energy input from the engine, meaning that it is not thermodynamically expensive. The implications of these results on HCCI and other forms of combustion are discussed in detail.

Szybist, James P [ORNL] [ORNL; Steeper, Richard R. [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Splitter, Derek A [ORNL] [ORNL; Kalaskar, Vickey B [ORNL] [ORNL; Pihl, Josh A [ORNL] [ORNL; Daw, C Stuart [ORNL] [ORNL

2014-01-01T23:59:59.000Z

218

Processing of prosthetic heart valve sounds for classification. Revision 1  

SciTech Connect (OSTI)

People with serious heart conditions have had their expected life span extended considerably with the development of the prosthetic heart valve especially with the great strides made in valve design. Even though the designs are extremely reliable, the valves are mechanical and operating continuously over a long period, therefore, structural failures can occur due to fatigue. Measuring heart sounds non-invasively in a noisy environment puts more demands on the signal processing to extract the desired signals from the noise. In this paper the authors discuss acoustical signal processing techniques developed to process noisy heart valve sounds measured by a sensitive, surface contact microphone and used for the eventual classification of the valve.

Candy, J.V.; Jones, H.E.

1994-04-01T23:59:59.000Z

219

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements  

SciTech Connect (OSTI)

People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.

Candy, J V; Meyer, A W

2001-03-20T23:59:59.000Z

220

System for remotely servicing a top loading captive ball valve  

DOE Patents [OSTI]

An attachment for facilitating servicing of a valve, the valve including: an assembly composed of a valve seat defining a flow path, a flow control member movable relative to the valve seat for blocking or unblocking the valve seat, and a control device including a stem coupled to the flow control member and operable for moving the flow control member relative to the valve seat; a housing for receiving the assembly, the housing having an opening via which the assembly can be removed from, and installed in, the housing, and the housing having a plurality of threaded studs which surround the opening and project away from the housing; a valve housing cover for closing and sealing the opening in the housing, the cover having a first bore for passage of the stem of the control device when the assembly is installed in the housing and a plurality of second bores each located for passage of a respective stud when the cover closes the opening in the housing. A plurality of threaded nuts are engageable with the studs for securing the cover to the housing when the cover closes the opening in the housing, wherein the attachment comprises: a plurality of nut guide devices removable from the housing and each operatively associated with a respective stud for retaining a respective nut and guiding the respective nut into alignment with the respective stud to enable the respective nut to be rotated into engagement with the respective stud; and aligning the nut guide devices with the studs.

Berry, Stephen M. (Idaho Falls, ID); Porter, Matthew L. (North Potomac, MD)

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

In-line real time air monitor  

DOE Patents [OSTI]

An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds.

Wise, Marcus B. (Kingston, TN); Thompson, Cyril V. (Knoxville, TN)

1998-01-01T23:59:59.000Z

222

In-line real time air monitor  

DOE Patents [OSTI]

An in-line gas monitor capable of accurate gas composition analysis in a continuous real time manner even under strong applied vacuum conditions operates by mixing an air sample with helium forming a sample gas in two complementary sample loops embedded in a manifold which includes two pairs of 3-way solenoid valves. The sample gas is then analyzed in an ion trap mass spectrometer on a continuous basis. Two valve drivers actuate the two pairs of 3-way valves in a reciprocating fashion, so that there is always flow through the in-line gas monitor via one or the other of the sample loops. The duty cycle for the two pairs of 3-way valves is varied by tuning the two valve drivers to a duty cycle typically between 0.2 to 0.7 seconds. 3 figs.

Wise, M.B.; Thompson, C.V.

1998-07-14T23:59:59.000Z

223

Analysis of a Third-Generation Princeton Tri-leaflet Mechanical Heart Valve  

E-Print Network [OSTI]

Analysis of a Third-Generation Princeton Tri-leaflet Mechanical Heart Valve Michael Hsu Advisor heart valve · Static analysis of leaflet under uniform pressure of 10 MPa Summer Objectives · Find Heart valve disease · Over 5 million affected · Over 225,000 valve- replacement surgeries performed

Petta, Jason

224

PCV valve flutter : vibration characterization through pressure and flow  

E-Print Network [OSTI]

A Positive Crankcase Ventilation, or PCV, valve is required by internal combustion engines in order to regulate the flow of blow-by gases out of the crankcase and into the intake air stream. Fluctuations in the pressure ...

Gomez, Nicasio

2005-01-01T23:59:59.000Z

225

Design of an electronically-actuated gas lift safety valve  

E-Print Network [OSTI]

Gas lift valves are widely used in oil production fields to pump recycled gas and nitrogen into the production tubing, to sustain production by aerating the oil and lifting it to the ground or sea surface. Today's industry ...

Yu, Changkuan, S.M. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

226

Spin-valve photodiode Ian Appelbaum,a)  

E-Print Network [OSTI]

Spin-valve photodiode Ian Appelbaum,a) D. J. Monsma, K. J. Russell, V. Narayanamurti, and C. M using internal photoemission to generate hot electrons in magnetic multilayer Schottky photodiodes

Russell, Kasey

227

Failure Mode and Sensitivity Analysis of Gas Lift Valves  

E-Print Network [OSTI]

Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valves. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure ...

Gilbertson, Eric W.

228

Friction and Wear Reduction in Diesel Engine Valve Trains  

Broader source: Energy.gov (indexed) [DOE]

commercial exhaust valve * Surface damage from 20,000 impacts displays micro-welding, plastic deformation, and transfer. 9 Managed by UT-Battelle for the Department of Energy...

229

Mechanisms of Oxidation-Enhanced Wear in Diesel Exhaust Valves...  

Broader source: Energy.gov (indexed) [DOE]

of wear oxidation microstructures of alloys Fe-, Ni-, Co-alloys h T h i h v Combined plastic deformation, wear, and oxidation on both valve and seat surfaces 6 Managed by...

230

International Environmental Agreements: Emissions trade, safety valves and escape clauses  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5 Escape clauses versus safety valves 13 6 Review of "standard model" of IEAs 14 6.1 Dynamics The effect of emissions trade on IEA participation 17 7.1 Ex ante heterogenous countries

Karp, Larry S.

231

Electric actuation of a surface controlled subsea safety valve  

E-Print Network [OSTI]

to the conversion of many components from hydraulic operation to electric. Therefore, it is the purpose of this report to detail and propose an engineering solution to the electrical conversion of a surface controlled subsea safety valve (SCSSV). Preliminary...

Bartlett, Timothy Joseph

2013-02-22T23:59:59.000Z

232

Automated auscultation : using acoustic features to diagnose mitral valve prolapse  

E-Print Network [OSTI]

During annual physical examinations, a primary-care physician listens to the heart using a stethoscope to assess the condition of the heart muscle and valves. This process, termed cardiac auscultation, is the primary means ...

Jung, Marcia Yeojin, 1982-

2004-01-01T23:59:59.000Z

233

Nonlinear springs with applications to flow regulation valves and mechanisms  

E-Print Network [OSTI]

This thesis focuses on the application of nonlinear springs for fluid flow control valves where geometric constraints, or fabrication technologies, limit the use of available solutions. Types of existing nonlinear springs ...

Freeman, David Calvin

2008-01-01T23:59:59.000Z

234

Replace Pressure-Reducing Valves with Backpressure Turbogenerators  

SciTech Connect (OSTI)

This revised ITP steam tip sheet on replacing pressure-reducing valves provides how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.

Not Available

2006-01-01T23:59:59.000Z

235

Signal processing of Shiley heart valve data for fracture detection  

SciTech Connect (OSTI)

Given digital acoustic data emanating from the heart sounds of the beating heart measured from laboratory sheep with implanted Bjoerk-Shiley Convexo-Concave heart valves, it is possible to detect and extract the opening and closing heart beats from the data. Once extracted, spectral or other information can then obtained from the heartbeats and passed on to feature extraction algorithms, neutral networks, or pattern recognizers so that the valve condition, either fractured or intact, may be determined.

Mullenhoff, C.

1993-04-01T23:59:59.000Z

236

Signal processing of Shiley heart valve data for fracture detection  

SciTech Connect (OSTI)

Given digital acoustic data emanating from the heart sounds of the beating heart measured from laboratory sheep with implanted Bjoerk-Shiley Convexo-Concave heart valves, it is possible to detect and extract the opening and closing heart beats from the data. Once extracted, spectral or other information can then obtained from the heartbeats and passed on to feature extraction algorithms, neural networks, or pattern recognizers so that the valve condition, either fractured or intact, may be determined.

Mullenhoff, C.

1993-09-01T23:59:59.000Z

237

Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies  

SciTech Connect (OSTI)

Delphi Automotive Systems and ORNL established this CRADA to advance the commercialization potential of the homogeneous charge compression ignition (HCCI) advanced combustion strategy for gasoline engine platforms. HCCI combustion has been shown by others to produce high diesel-like efficiency on a gasoline engine platform while simultaneously producing low NOX and particulate matter emissions. However, the commercialization barriers that face HCCI combustion are significant, with requirements for a more active engine control system, likely with next-cycle closed-loop feedback control, and with advanced valve train technologies to enable negative valve overlap conditions. In the partnership between Delphi and ORNL, each organization brought a unique and complementary set of skills to the project. Delphi has made a number of breakthroughs with production-intent valve train technologies and controls in recent years to make a part time production-intent HCCI engine plausible. ORNL has extensive knowledge and expertise with HCCI combustion, and also has a versatile research engine with hydraulic valve actuation (HVA) that is useful for guiding production of a cam-based HCCI system. Partnering these knowledge bases and capabilities was essential towards making progress to better understand HCCI combustion and the commercialization barriers that it faces. ORNL and Delphi maintained strong collaboration throughout the project. Meetings were held regularly, with additional reports, presentations, and meetings as necessary to maintain progress. Delphi provided guidance to ORNL regarding operational strategies to investigate on their single-cylinder research engine with HVA and data from their experimental multi-cylinder engine for modeling. ORNL provided single-cylinder engine data and modeling results.

Szybist, J. P. [Oak Ridge National Lab., Oak Ridge, TN (United States); Confer, K. [Delphi Automotive Systems (United States)

2012-09-11T23:59:59.000Z

238

System for remotely servicing a top loading captive ball valve  

DOE Patents [OSTI]

An attachment for facilitating servicing of a valve is disclosed including: an assembly composed of a valve seat defining a flow path, a flow control member movable relative to the valve seat for blocking or unblocking the valve seat, and a control device including a stem coupled to the flow control member and operable for moving the flow control member relative to the valve seat; a housing for receiving the assembly, the housing having an opening via which the assembly can be removed from, and installed in, the housing, and the housing having a plurality of threaded studs which surround the opening and project away from the housing; a valve housing cover for closing and sealing the opening in the housing, the cover having a first bore for passage of the stem of the control device when the assembly is installed in the housing and a plurality of second bores each located for passage of a respective stud when the cover closes the opening in the housing. A plurality of threaded nuts are engageable with the studs for securing the cover to the housing when the cover closes the opening in the housing, wherein the attachment comprises: a plurality of nut guide devices removable from the housing and each operatively associated with a respective stud for retaining a respective nut and guiding the respective nut into alignment with the respective stud to enable the respective nut to be rotated into engagement with the respective stud; and aligning the nut guide devices with the studs. 7 figs.

Berry, S.M.; Porter, M.L.

1996-06-25T23:59:59.000Z

239

Valving for controlling a fluid-driven reciprocating apparatus  

DOE Patents [OSTI]

A pair of control valve assemblies for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump.

Whitehead, John C. (Davis, CA)

1995-01-01T23:59:59.000Z

240

Valving for controlling a fluid-driven reciprocating apparatus  

DOE Patents [OSTI]

A pair of control valve assemblies is described for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart`s piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump. 15 figs.

Whitehead, J.C.

1995-06-27T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Gas lift valve failure mode analysis and the design of a thermally-actuated positive-locking safety valve  

E-Print Network [OSTI]

Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valves. This is a growing concern as offshore wells are drilled thousands of meters below the ocean floor in extreme temperature and pressure ...

Gilbertson, Eric (Eric W.)

2010-01-01T23:59:59.000Z

242

Monovalve with integrated fuel injector and port control valve, and engine using same  

DOE Patents [OSTI]

An engine includes an engine casing that defines a hollow piston cavity separated from an exhaust passage and an intake passage by a valve seat. A gas exchange valve member is positioned adjacent the valve seat and is moveable between an open position and a closed position. The gas exchange valve member also defines an opening that opens into the hollow piston cavity. A needle valve member is positioned in the gas exchange valve member adjacent a nozzle outlet and is moveable between an inject position and a blocked position. A port control valve member, which has a hydraulic surface, is mounted around the gas exchange valve member and moveable between an intake position and an exhaust position. A pilot valve is moveable between a first position at which the port control hydraulic surface is exposed to a source of high pressure fluid, and a second position at which the port control hydraulic surface is exposed to a source of low pressure fluid.

Milam, David M. (Metamora, IL)

2001-11-06T23:59:59.000Z

243

Engine including hydraulically actuated valvetrain and method of valve overlap control  

DOE Patents [OSTI]

An exhaust valve control method may include displacing an exhaust valve in communication with the combustion chamber of an engine to an open position using a hydraulic exhaust valve actuation system and returning the exhaust valve to a closed position using the hydraulic exhaust valve actuation assembly. During closing, the exhaust valve may be displaced for a first duration from the open position to an intermediate closing position at a first velocity by operating the hydraulic exhaust valve actuation assembly in a first mode. The exhaust valve may be displaced for a second duration greater than the first duration from the intermediate closing position to a fully closed position at a second velocity at least eighty percent less than the first velocity by operating the hydraulic exhaust valve actuation assembly in a second mode.

Cowgill, Joel (White Lake, MI)

2012-05-08T23:59:59.000Z

244

HCCI in a Variable Compression Ratio Engine: Effects of Engine...  

Broader source: Energy.gov (indexed) [DOE]

Fuels Practical Full Time HCCI Operation Will Require Specific HCCI Fuel Low Octane gasoline Experimental Variables Experimental Variables Engine Variables Intake Manifold...

245

ISOLOK VALVE ACCEPTANCE TESTING FOR DWPF SME SAMPLING PROCESS  

SciTech Connect (OSTI)

Evaluation of the Defense Waste Processing Facility (DWPF) Chemical Process Cell (CPC) cycle time identified several opportunities to improve the CPC processing time. Of the opportunities, a focus area related to optimizing the equipment and efficiency of the sample turnaround time for DWPF Analytical Laboratory was identified. The Mechanical Systems & Custom Equipment Development (MS&CED) Section of the Savannah River National Laboratory (SRNL) evaluated the possibility of using an Isolok{reg_sign} sampling valve as an alternative to the Hydragard{reg_sign} valve for taking process samples. Previous viability testing was conducted with favorable results using the Isolok sampler and reported in SRNL-STI-2010-00749 (1). This task has the potential to improve operability, reduce maintenance time and decrease CPC cycle time. This report summarizes the results from acceptance testing which was requested in Task Technical Request (TTR) HLW-DWPF-TTR-2010-0036 (2) and which was conducted as outlined in Task Technical and Quality Assurance Plan (TTQAP) SRNL-RP-2011-00145 (3). The Isolok to be tested is the same model which was tested, qualified, and installed in the Sludge Receipt Adjustment Tank (SRAT) sample system. RW-0333P QA requirements apply to this task. This task was to qualify the Isolok sampler for use in the DWPF Slurry Mix Evaporator (SME) sampling process. The Hydragard, which is the current baseline sampling method, was used for comparison to the Isolok sampling data. The Isolok sampler is an air powered grab sampler used to 'pull' a sample volume from a process line. The operation of the sampler is shown in Figure 1. The image on the left shows the Isolok's spool extended into the process line and the image on the right shows the sampler retracted and then dispensing the liquid into the sampling container. To determine tank homogeneity, a Coliwasa sampler was used to grab samples at a high and low location within the mixing tank. Data from the two locations were compared to determine if the contents of the tank were well mixed. The Coliwasa sampler is a tube with a stopper at the bottom and is designed to obtain grab samples from specific locations within the drum contents. A position paper (4) was issued to address the prototypic flow loop issues and simulant selections. A statistically designed plan (5) was issued to address the total number of samples each sampler needed to pull, to provide the random order in which samples were pulled and to group samples for elemental analysis. The TTR required that the Isolok sampler perform as well as the Hydragard sampler during these tests to ensure the acceptability of the Isolok sampler for use in the DWPF sampling cells. Procedure No.L9.4-5015 was used to document the sample parameters and process steps. Completed procedures are located in R&D Engineering job folder 23269.

Edwards, T.; Hera, K.; Coleman, C.; Jones, M.; Wiedenman, B.

2011-12-05T23:59:59.000Z

246

System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems  

DOE Patents [OSTI]

A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

Brennan, Daniel G; Marriott, Craig D; Cowgill, Joel; Wiles, Matthew A; Patton, Kenneth James

2014-09-23T23:59:59.000Z

247

Reduced-impact sliding pressure control valve for pneumatic hammer drill  

DOE Patents [OSTI]

A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

Polsky, Yarom (Oak Ridge, TN); Grubelich, Mark C. (Albuquerque, NM); Vaughn, Mark R. (Albuquerque, NM)

2012-05-15T23:59:59.000Z

248

Engine control system having pressure-based timing  

DOE Patents [OSTI]

A control system for an engine having a first cylinder and a second cylinder is disclosed having a first engine valve movable to regulate a fluid flow of the first cylinder and a first actuator associated with the first engine valve. The control system also has a second engine valve movable to regulate a fluid flow of the second cylinder and a sensor configured to generate a signal indicative of a pressure within the first cylinder. The control system also has a controller that is in communication with the first actuator and the sensor. The controller is configured to compare the pressure within the first cylinder with a desired pressure and selectively regulate the first actuator to adjust a timing of the first engine valve independently of the timing of the second engine valve based on the comparison.

Willi, Martin L. (Dunlap, IL); Fiveland, Scott B. (Metamora, IL); Montgomery, David T. (Edelstein, IL); Gong, Weidong (Dunlap, IL)

2011-10-04T23:59:59.000Z

249

Classification of prosthetic heart valve sounds. A parametric approach  

SciTech Connect (OSTI)

People with heart problems have had their lives extended considerably with the development of the prosthetic heart valve. Great strides have been made in the development of the valves through the use of improved materials as well as efficient mechanical designs. However, since the valves operate continuously over a long period, structural failures can occur-even though they are relatively uncommon. Here the development of techniques to classify the valve either as having intact struts or as having a separated strut, commonly called single leg separation, is discussed. In this paper the signal processing techniques employed to extract the required signals/parameters are briefly reviewed and then it is shown how they can be used to simulate a synthetic heart valve database for eventual Monte Carlo testing. Next, the optimal classifier is developed under assumed conditions and its performance is compared to that of an adpative-type classifier implemented with a probabilistic neural network. Finally, the adaptive classifier is applied to a data set and its performance is analyzed. Based on synthetic data it is shown that excellent performance of the classifiers can be achieved implying a potentially robust solution to this classification problem. 21 refs., 11 figs., 1 tab.

Candy, J.V.; Jones, H.E. [Univ. of California, Livermore, CA (United States)]|[Lawrence Livermore National Lab., CA (United States)

1995-06-01T23:59:59.000Z

250

Measuring while drilling apparatus mud pressure signal valve  

SciTech Connect (OSTI)

This patent describes a measurement while drilling system for borehole drilling having a downhole instrument connectable in a drill string of a rotary drilling rig including apparatus to sense geological and geophysical parameters and a valve apparatus to pulse modulate drilling fluid flowing in the drill string. A surface apparatus is connected to a drilling fluid flow conductor for extracting intelligence carrying information from the modulated drilling fluid. An improved valve apparatus is described comprising: (a) a drilling fluid flow pulse modulating pressure pulse valve member longitudinally, movably mounted in a body member and movable from a retracted position substantially removed from the drilling fluid flow and an extended position disposed at least partially within the drilling fluid flow thereby temporarily restricting drilling fluid flow within the drill string; and (b) the pulse valve member is a tubular member having a lower end portion displaceable from the body member into the drilling fluid and an upper end portion with opposed fluid pressure force areas thereon being in fluid communication with the drilling fluid flow such that forces due to the drilling fluid acting on the pressure pulse valve member are balanced in a longitudinal direction.

Peppers, J.M.; Shaikh, F.A.

1986-12-09T23:59:59.000Z

251

High-resolution moisture fields retrieved for the first time from both operational and research radars illustrate the low-level moisture variability associated with boundary layer  

E-Print Network [OSTI]

radars illustrate the low-level moisture variability associated with boundary layer processes-Resolution, Low-Level Moisture Fields from Operational NexRad and Research Radars by Rita D. RobeRts, FRéDéRic Fab vapor measurements extracted from radar using an index of refraction (refractivity) technique developed

Reising, Steven C.

252

Low power integrated pumping and valving arrays for microfluidic systems  

DOE Patents [OSTI]

Low power integrated pumping and valving arrays which provide a revolutionary approach for performing pumping and valving approach for performing pumping and valving operations in microfabricated fluidic systems for applications such as medical diagnostic microchips. Traditional methods rely on external, large pressure sources that defeat the advantages of miniaturization. Previously demonstrated microfabrication devices are power and voltage intensive, only function at sufficient pressure to be broadly applicable. This approach integrates a lower power, high-pressure source with a polymer, ceramic, or metal plug enclosed within a microchannel, analogous to a microsyringe. When the pressure source is activated, the polymer plug slides within the microchannel, pumping the fluid on the opposite side of the plug without allowing fluid to leak around the plug. The plugs also can serve as microvalves.

Krulevitch, Peter A. (Pleasanton, CA); Benett, William J. (Livermore, CA); Rose, Klint A. (Livermore, CA); Hamilton, Julie (Tracy, CA); Maghribi, Mariam (Davis, CA)

2006-04-11T23:59:59.000Z

253

Drive piston assembly for a valve actuator assembly  

DOE Patents [OSTI]

A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

Sun, Zongxuan (Troy, MI)

2010-02-23T23:59:59.000Z

254

Design and fabrication of microfluidic valves using poly(N-isopropylacrylamide)  

E-Print Network [OSTI]

A compact printable microfluidic valve composed of poly(N-isopropylacrylamide) has been designed, fabricated, and tested. The design of the valve consists of filling microwells with poly(NIPAAm) and bonding PDMS channels ...

Reticker-Flynn, Nathan Edward

2008-01-01T23:59:59.000Z

255

E-Print Network 3.0 - aortic valve area Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

<< < 1 2 3 4 5 > >> 1 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: fluid velocity and aortic valve opening area (AVA) at each age. These...

256

E-Print Network 3.0 - aortic heart valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

heart valve Search Powered by Explorit Topic List Advanced Search Sample search results for: aortic heart valve Page: << < 1 2 3 4 5 > >> 1 Non-Invasive Evaluation of Opening and...

257

E-Print Network 3.0 - aortic valve regurgitation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

regurgitation Page: << < 1 2 3 4 5 > >> 1 Interaction between the mitral and aortic heart valve Summary: or regurgitation. In 2001, of all valve diseases in the left ventricle,...

258

E-Print Network 3.0 - aortic valve thickening Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

<< < 1 2 3 4 5 > >> 1 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: of a normal, healthy valve thicken and become less extensible over...

259

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

E-Print Network [OSTI]

Rendering the Electromechanical Valve Actuator Globally Asymptotically Stable Katherine S. Peterson to render the electromechanical valve actuator (EVA) globally asymptotically stable (GAS). Elec model. Here, we demonstrate and prove that our controller renders the system GAS without any assumption

Stefanopoulou, Anna

260

Eaton Throat-Valve Element prototype concept. Phase 1  

SciTech Connect (OSTI)

As part of an ongoing effort to improve techniques for simulating nuclear blasts, the US Army Research Laboratory has been studying the merits of computer-controlled valves. The valve studies have been aimed at providing the Department of Defense with the capacity to conduct nuclear blast and thermal survivability testing on full-scale tactical vehicles. This report documents the development and findings of a computer model that simulates the behavior of the Eaton-Throat Valve Element (ETVE) prototype, and describes a proposed modification concept for the ETVE. The computer model reveals three main findings: (1) the ETVE chatters during the open cycle, (2) the chatter is caused by the high gas forces on the sliding sleeve as the driver gas passes through its portholes, and (3) the chatter is aggravated because there is insufficient damping in the system. The INEL recommends opening the ETVE by sliding the sleeve toward the downstream end of the valve instead of toward the upstream end, as the ETVE is presently configured, and to provide additional damping to the system. However, neither of these configuration changes can be achieved easily, and a redesign and analysis f the ETVE must be completed prior to performing any work on the current ETVE prototype. The ETVE simulation model proved to be an extremely valuable tool in analyzing the qualitative nature of the valve`s operation. Further development of the model is recommended for quantitative analysis and design of the ETVE. This report explains the model and stress analysis findings, and proposes a redesign concept.

Stacey, M.R.; Arendts, J.G.; Berry, R.A.; Korth, G.E.; Schwieder, P.R.; Sekot, J.P.; Snow, S.D.

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Piping retrofit reduces valve-damaging flow vibration  

SciTech Connect (OSTI)

This article describes how excessive flow-induced vibration was escalating safety relief valve maintenance at an alarming pace until simple piping modifications eliminated the problem. Public Service Co. of Colorado's (PSCO) Cherokee Station Unit 4 had been experiencing excessive hot and cold reheat safety valve maintenance. From 1990 through 1993, expenditures exceeded $150,000, including a complete refurbishing in 1990. Furthermore, from 1990 to 1992 the incurred costs of contracting VR certificate repairs accumulated to more than $50,000. Such exorbitant maintenance costs were unique among PSCO's generating system.

Webb, M.; Ellenberger, P.

1995-01-01T23:59:59.000Z

262

Fuel Composition Effects at Constant RON and MON in an HCCI Engine Operated with Negative Valve Overlap  

SciTech Connect (OSTI)

The effects of fuel properties on gasoline HCCI operation have been investigated in a single cylinder, 500 cc, 11.3 CR port fuel injected research engine, operated at lambda=1 and equipped with hydraulic valve actuation. HCCI is promoted by early exhaust valve closing to retain hot exhaust in the cylinder, thereby increasing the cylinder gas temperature. Test fuels were formulated with pure components to have the same RON, MON, and octane sensitivity as an indolene reference fuel, but with a wide range of fuel composition differences. Experiments have been carried out to determine if fuel composition plays a role in HCCI combustion properties, independent of octane numbers. Fuel economy, emissions, and combustion parameters have been measured at several fixed speed/load conditions over a range of exhaust valve closing angles. When the data are compared at constant combustion phasing, fuel effects on emissions and other combustion properties are small. However, when compared at constant exhaust valve closing angle, fuel composition effects are more pronounced, specifically regarding ignition. Operability range differences are also related to fuel composition. An all-paraffinic (normal, iso, and cycloparaffins) fuel exhibited distinctly earlier combustion phasing, increased rate of cylinder pressure rise, and increased rate of maximum heat release compared to the indolene reference fuel. Conversely, olefin-containing fuels exhibited retarded combustion phasing. The fuels with the most advanced ignition showed a wider operating range in terms of engine speed and load, irrespective of exhaust closing angle. These ignition differences reflect contributions from both fuel and EGR kinetics, the effects of which are discussed. The fuel composition variables are somewhat inter-correlated, which makes the experimental separation their effects imprecise with this small set of fuels, though clear trends are evident. The overall effects of fuel composition on engine performance and emissions are small. However, the results suggest that the effects on combustion phasing and engine operability range may need to be considered in the practical implementation of HCCI for fuels with large compositional variations.

Bunting, Bruce G [ORNL; Farrell, John T [Exxon Mobil Research and Engineering

2006-01-01T23:59:59.000Z

263

Monovalve with integrated fuel injector and port control valve, and engine using same  

DOE Patents [OSTI]

Each cylinder of an internal combustion engine includes a combined gas exchange valve and fuel injector with a port control valve. The port control valve operates to open either an intake passage or an exhaust passage. The operation of the combined device is controlled by a pair of electrical actuators. The device is hydraulically actuated.

Milam, David M. (Metamora, IL)

2002-01-01T23:59:59.000Z

264

Wear and wear mechanism simulation of heavy-duty engine intake valve and seat inserts  

SciTech Connect (OSTI)

A silicon-chromium alloy frequently used for heavy-duty diesel engine intake valves was tested against eight different insert materials with a valve seat wear simulator. Wear resistance of these combinations was ranked. For each test, the valve seat temperature was controlled at approximately 510 C, the number of cycles was 864,000 (or 24 h), and the test load was 17,640 N. The combination of the silicon-chromium valve against a cast iron insert produced in the least valve seat wear, whereas a cobalt-base alloy insert produced the highest valve seat wear. In the overall valve seat recession ranking, however, the combination of the silicon-chromium valve and an iron-base chromium-nickel alloy insert had the least total seat recession, whereas the silicon-chromium valve against cobalt-base alloy, cast iron, and nickel-base alloy inserts had significant seat recession. Hardness and microstructure compatibility of valve and insert materials are believed to be significant factors in reducing valve and insert wear. The test results indicate that the mechanisms of valve seat and insert wear are a complex combination of adhesion and plastic deformation. Adhesion was confirmed by material transfer, while plastic deformation was verified by shear strain (or radial flow) and abrasion. The oxide films formed during testing also played a significant role. The prevented direct metal-to-metal contact and reduced the coefficient of friction on seat surfaces, thereby reducing adhesive and deformation-controlled wear.

Wang, Y.S.; Narasimhan, S.; Larson, J.M.; Schaefer, S.K. [Eaton Corp., Marshall, MI (United States). Engine Components Operations] [Eaton Corp., Marshall, MI (United States). Engine Components Operations

1998-02-01T23:59:59.000Z

265

APPLICATION OF BUTTERFLY VALVES FOR FREE DISCHARGE, MINIMUM PRESSURE DROP, AND FOR CHOKING CAVITATION  

E-Print Network [OSTI]

CAVITATION Butterfly valves are commonly used as control valves in applications where the pressure drops and the use of a butterfly valve for flashing or choking cavitation service. Free discharge typically produces high pipe velocities at moderate pressure drops, and choking cavitation typically produces high

Rahmeyer, William J.

266

Worcester 1 Inch Solenoid Actuated Gas Operated VPS System Ball Valve  

SciTech Connect (OSTI)

1 inch Gas-operated full-pod ball valve incorporates a solenoid and limit switches as integral park of the actuator. The valve is normally open and fails safe to the closed position. The associated valve position switch is class GS.

MISKA, C.R.

2000-11-13T23:59:59.000Z

267

Experimental study on the cause of insufficiency of a transcutaneous pulmonary valve replacement  

E-Print Network [OSTI]

Experimental study on the cause of insufficiency of a transcutaneous pulmonary valve replacement for the replacement of pulmonary heart valves. This technique is a minimally invasive alternative to the replacement on known causes for insufficiencies of transcutaneous heart valve replacements. Out of that information

Berlin,Technische Universität

268

Pumps, pipes and valves: The heart of a system  

SciTech Connect (OSTI)

This is a guide to suppliers of pumps, pipes and valves for construction or repair of hazardous materials. The article contains a compilation of the suppliers/manufacturers and how to contact them, the corrosion resistance of the component, whether double-secondary containment is available, and the material used to construct the component.

NONE

1996-05-01T23:59:59.000Z

269

Covered Product Category: Pre-Rinse Spray Valves  

Broader source: Energy.gov [DOE]

The Federal Energy Management Program (FEMP) provides acquisition guidance and Federal efficiency requirements across a variety of product categories, including pre-rinse spray valves, which are a FEMP-designated product category. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

270

Motor current signature analysis for determining operational readiness of motor-operated valves (MOVs)  

SciTech Connect (OSTI)

Motor current signature analysis (MCSA) is a novel diagnostic process for condition monitoring of electric-motor-driven mechanical equipment (e.g., pumps, motor-operated valves, compressors, and processing machinery). The MCSA process identifies, characterizes, and trends over time the instantaneous load variations of mechanical equipment in order to diagnose changes in the condition of the equipment (e.g., due to degradation or service wear), which, if allowed to continue, may lead to failure. It monitors the instantaneous variations (noise content) in the electric current flowing through the power leads to the electric motor that drives the equipment. The motor itself thereby acts as a transducer, sensing both large and small, long-term and rapid, mechanical load variations and converting them to variations in the induced current generated in the motor windings. This motor current noise signature is detected, amplified, and further processed as needed to examine its time domain and frequency domain (spectral) characteristics. The operational principles of MCSA and the nonintrusive data collection apparatus and procedure used with MOVs will be described. Data collected from MOVs in both laboratory and in-plant environments will also be shown to illustrate the ability of MCSA to ''see'' the detailed inner workings of the valve and operator and thus to detect degraded performance at an incipient stage. (Set of 18 vugraphs)

Kryter, R.C.; Haynes, H.D.

1987-01-01T23:59:59.000Z

271

Plastic-lined valves are virtually trouble-free in caustic, acid pipelines  

SciTech Connect (OSTI)

Chevron renovated the naphthenic acid plant, part of the Pascagoula, Mississippi Refinery of Chevron U.S.A. Inc., in mid-1979. They installed plastic-lined valves in the caustic and acid water piping systems. The valves combine the excellent sealing characteristics of a plug valve with the minimal rotary contact surface and low pressure drop of a butterfly valve. The valve has a molded-in-place PTFE liner resistant to abrasives and corrosives at temperatures of 450/sup 0/F, and is rated for pressures from full vacuum to 150 psi.

Not Available

1983-02-01T23:59:59.000Z

272

Aging and service wear of air-operated valves used in safety-related systems at nuclear power plants  

SciTech Connect (OSTI)

Air-operated valves (AOVs) are used in a variety of safety-related applications at nuclear power plants. They are often used where rapid stroke times are required or precise control of the valve obturator is required. They can be designed to operate automatically upon loss of power, which is often desirable when selecting components for response to design basis conditions. The purpose of this report is to examine the reported failures of AOVs and determine whether there are identifiable trends in the failures related to predictable causes. This report examines the specific components that comprise a typical AOV, how those components fail, when they fail, and how such failures are discovered. It also examines whether current testing frequencies and methods are effective in predicting such failures.

Cox, D.F.; McElhaney, K.L.; Staunton, R.H.

1995-05-01T23:59:59.000Z

273

Combustion engine with fuel injection system, and a spray valve for such an engine  

SciTech Connect (OSTI)

This paper describes a fuel system for a combustion engine have a cylinder with an air inlet passage. It comprises: a fuel spray valve having a fuel injection nozzle for spraying fuel into the cylinder air inlet passage and having a fuel spray valve passage leading to the nozzle, means for mounting the fuel spray valve to position the nozzle to open into the cylinder air inlet passage adjacent the cylinder, a fuel pump for providing fuel under pressure to the fuel spray valve passage to be sprayed from the fuel spray valve nozzle, and a fuel heating device connectable to an electrical power supply and disposed adjacent to the valve to be energized for heating the fuel to enhance finer spraying thereof by the fuel spray valve nozzle, the fuel heating device comprising means defining a spiral fuel flow path of selected length connected to and coaxial with the fuel spray valve passage to dispose the selected length of fuel flow path closely adjacent to the fuel spray valve passage, and a fuel heating element comprising a thermistor of a ceramic material of positive temperature coefficient of resistivity arranged to heat the selected length of the spiral fuel flow path to transfer heat to the fuel flowing in the spiral fuel flow path throughout the selected length of the spiral fuel flow path to substantially heat the fuel at a location closely adjacent to the fuel spray valve passage to enhance vaporizing of fuel being sprayed from the valve nozzle.

Wechem, G.V.; Beunk, G.; Van Den Elst, F.; Gerson, P.M.

1991-10-08T23:59:59.000Z

274

Nondestructive evaluation of silicon-nitride ceramic valves from engine duration test.  

SciTech Connect (OSTI)

In this study, we investigated impact and wear damage in silicon-nitride ceramic valves that were subjected to an engine duration test in a natural-gas engine. A high-speed automated laser-scattering system was developed for the nondestructive evaluation (NDE) of 10 SN235P silicon-nitride valves. The NDE system scans the entire valve surface and generates a two-dimensional scattering image that is used to identify location, size and relative severity of subsurface damage in the valves. NED imaging data were obtained at before and at 100 and 500 hours of the engine duration test. The NDE data were analyzed and compared with surface photomicrographs. Wear damage was found in the impact surface of all valves, expecially for exhaust valves. However, the NDE examination did not detect subsurface damage such as cracks or spalls in these engine-tested valves.

Sun, J. G.; Trethewey, J. S.; Vanderspiegle, N. N.; Jensen, J. A.; Nuclear Engineering Division; Caterpillar, Inc.

2008-01-01T23:59:59.000Z

275

Magnetism reflectometer study shows LiF layers improve efficiency in spin valve devices  

SciTech Connect (OSTI)

New, more efficient materials for spin valves - a device used in magnetic sensors, random access memories, and hard disk drives - may be on the way based on research using the magnetism reflectometer at Oak Ridge National Laboratory (ORNL). Spin valve devices work by means of two or more conducting magnetic material layers that alternate their electrical resistance depending on the layers alignment. Giant magnetoresistance is a quantum mechanical effect first observed in thin film structures about 20 years ago. The effect is observed as a significant change in electrical resistance, depending on whether the magnetization of adjacent ferromagnetic layers is in a parallel or an antiparallel magnetic alignment. 'What we are doing here is developing new materials. The search for new materials suitable for injecting and transferring carriers with a preferential spin orientation is most important for the development of spintronics,' said Valeria Lauter, lead instrument scientist on the magnetism reflectometer at the Spallation Neutron Source (SNS), who collaborated on the experiment. The researchers discovered that the conductivity of such materials is improved when an organic polymer semiconductor layer is placed between the magnetic materials. Organic semiconductors are now the material of choice for future spin valve devices because they preserve spin coherence over longer times and distances than conventional semiconductors. While research into spin valves has been ongoing, research into organic semiconductors is recent. Previous research has shown that a 'conductivity mismatch' exists in spin valve systems in which ferromagnetic metal electrodes interface with such organic semiconductors as Alq3 ({pi}-conjugated molecule tris(8-hydroxy-quinoline) aluminium). This mismatch limits the efficient injection of the electrons from the electrodes at the interface with the semiconductor material. However, lithium fluoride (LiF), commonly used in light-emitting diodes, has been found to enhance the injection of electrons through the semiconductor. Researchers from the University of Alabama and ORNL used polarized neutrons at the magnetism reflectometer at SNS to investigate the electronic, magnetic, and structural properties of the electrodes in a novel system. In this system, the magnetic layers cobalt and Ni{sub 80}Fe{sub 20} are interfaced with spacer layers composed of the organic semiconductor Alq3. A coupling layer of LiF is inserted to separate the magnetized layers from the semiconductor. 'ALQ3 is an organic semiconductor material,' said Lauter. 'Normally in these systems a first magnetic layer is grown on a hard substrate so that one can get the controlled magnetic parameters. Then you grow the organic semiconductor layer, followed by another magnetic material layer, such as cobalt.' In addition to determining the effect of the LiF layers on the efficiency of the electron injection, the researchers wanted to determine the magnetic properties of the cobalt and Ni{sub 80}Fe{sub 20} as well as the interfacial properties: whether there is interdiffusion of cobalt through the LiF layer to the semiconductor, for example. The researchers used polarized neutrons at beam line 4A to probe the entire, layer-by-layer assembly of the system. 'Reflectometry with polarized neutrons is a perfect method to study thin magnetic films,' Lauter said. 'These thin films - if you put one on a substrate, you see it just like a mirror. However, this mirror has a very complicated internal multilayer structure. The neutrons look inside this complicated structure and characterize each and every interface. Due to the depth sensitivity of the method, we measure the structural and magnetic properties of each layer with the resolution of 0.5 nm. The neutron scattering results found that inserting LiF as a barrier significantly improves the quality of the interface, increasing the injection of electrons from the magnetic layer through the organic semiconductor in the spin valve and enhancing the overall properties of the system. In related work the magneti

Bardoel, Agatha A [ORNL; Lauter, Valeria [ORNL; Szulczewski, Greg J [ORNL

2012-01-01T23:59:59.000Z

276

2012-01-1106 Understanding the dynamic evolution of cyclic variability at the  

E-Print Network [OSTI]

of HCCI engines with negative valve overlap Erik Hellström, Anna Stefanopoulou, Jiri Vavra, Aristotelis ignition (HCCI) combustion focusing on late phas- ing conditions with high cyclic variability (CV of HCCI. A combustion analysis method is developed for explaining the dynamic coupling in sequences

Stefanopoulou, Anna

277

Cataclysmic Variables  

E-Print Network [OSTI]

Cataclysmic variables are binary stars in which a relatively normal star is transferring mass to its compact companion. This interaction gives rise to a rich range of behaviour, of which the most noticeable are the outbursts that give the class its name. Novae belong to the class, as do the less well known dwarf novae and magnetic systems. Novae draw their energy from nuclear reactions, while dwarf novae rely on gravity to power their smaller eruptions. All the different classes of cataclysmic variable can be accommodated within a single framework and this article will describe the framework, review the properties of the main types of system and discuss models of the outbursts and of the long-term evolution.

Robert Connon Smith

2007-01-23T23:59:59.000Z

278

Production-Intent Lost-Motion Variable Valve Actuation Systems | Department  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion | Department ofT ib l L d FNEPA/309Department ofDepartment of Energy Production ofof

279

1999 Hazeleger, W., 1 February 1999. Variability in Mode Water Formation on the Decadal Time Scale. University of Utrecht, the Netherlands.  

E-Print Network [OSTI]

Time Scale. University of Utrecht, the Netherlands. Lipzig, N.P.M. van, 6 October 1999. The surfaceD-Thesis, University of Utrecht, the Netherlands. Veefkind, J.P., 11 October 1999. Aerosol Satellite Remote Sensing. PhD-Thesis, University of Utrecht, the Netherlands. Bosveld, F.C., 3 November 1999. Exchange processes between a Douglas

Haak, Hein

280

THE EFFECTS OF MAINTENANCE ACTIONS ON THE PFDavg OF SPRING OPERATED PRESSURE RELIEF VALVES  

SciTech Connect (OSTI)

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

Harris, S.; Gross, R.

2014-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Removable check valve for use in a nuclear reactor  

DOE Patents [OSTI]

A removable check valve for interconnecting the discharge duct of a pump and an inlet coolant duct of a reactor core in a pool-type nuclear reactor. A manifold assembly is provided having an outer periphery affixed to and in fluid communication with the discharge duct of the pump and has an inner periphery having at least one opening therethrough. A housing containing a check valve is located within the inner periphery of the manifold. The upper end of the housing has an opening in alignment with the opening in the manifold assembly, and seals are provided above and below the openings. The lower end of the housing is adapted for fluid communication with the inlet duct of the reactor core.

Dunn, Charlton (Calabasas, CA); Gutzmann, Edward A. (Simi Valley, CA)

1988-01-01T23:59:59.000Z

282

Spin transport in benzofurane bithiophene based organic spin valves  

SciTech Connect (OSTI)

In this paper we present spin transport in organic spin-valves using benzofurane bithiophene (BF3) as spacer layer between NiFe and Co ferromagnetic electrodes. The use of an AlO{sub x} buffer layer between the top electrode and the organic layer is discussed in terms of improvements of stacking topology, electrical transport and oxygen contamination of the BF3 layer. A study of magnetic hysteresis cycles evidences spin-valve behaviour. Transport properties are indicative of unshorted devices with non-linear I-V characteristics. Finally we report a magnetoresistance of 3% at 40 K and 10 mV in a sample with a 50 nm thick spacer layer, using an AlO{sub x} buffer layer.

Palosse, Mathieu; Sguy, Isabelle; Bedel-Pereira, lena [CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse (France) [CNRS, LAAS, 7 avenue du Colonel Roche, F-31400 Toulouse (France); Universit de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France)] [France; Villeneuve-Faure, Christina [Universit de Toulouse (France) [Universit de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; LAPLACE, Universit Paul Sabatier, 118, route de Narbonne 31062 Toulouse Cedex 9 (France); Mallet, Charlotte; Frre, Pierre [MOLTECH-Anjou, UMR CNRS 6200, Universit dAngers, 2 Bd Lavoisier 49045 ANGERS Cedex (France)] [MOLTECH-Anjou, UMR CNRS 6200, Universit dAngers, 2 Bd Lavoisier 49045 ANGERS Cedex (France); Warot-Fonrose, Bndicte; Biziere, Nicolas [Universit de Toulouse (France) [Universit de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; CNRS, CEMES-CNRS UPR 8011, 29 rue Jeanne Marvig, BP 94347, FR-31055 Toulouse Cedex 4 (France); Bobo, Jean-Franois, E-mail: jfbobo@cemes.fr [Universit de Toulouse (France) [Universit de Toulouse (France); UPS, INSA, INP, ISAE (France); LAAS (France) [France; CEMES, F-31077 Toulouse (France) [France; CNRS, CEMES-ONERA, NMH, 2 avenue Edouard Belin, FR-31055 Toulouse Cedex 4 (France)

2014-01-15T23:59:59.000Z

283

Engine control system having speed-based timing  

DOE Patents [OSTI]

A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a controller in communication with the actuator. The controller is configured to receive a signal indicative of engine speed and compare the engine speed signal with a desired engine speed. The controller is also configured to selectively regulate the actuator to adjust a timing of the engine valve to control an amount of air/fuel mixture delivered to the cylinder based on the comparison.

Willi, Martin L. (Dunlap, IL); Fiveland, Scott B. (Metamora, IL); Montgomery, David T. (Edelstein, IL); Gong, Weidong (Dunlap, IL)

2012-02-14T23:59:59.000Z

284

Engine control system having fuel-based timing  

DOE Patents [OSTI]

A control system for an engine having a cylinder is disclosed having an engine valve movable to regulate a fluid flow of the cylinder and an actuator associated with the engine valve. The control system also has a sensor configured to generate a signal indicative of an amount of an air/fuel mixture remaining within the cylinder after completion of a first combustion event and a controller in communication with the actuator and the sensor. The controller may be configured to compare the amount with a desired amount, and to selectively regulate the actuator to adjust a timing of the engine valve associated with a subsequent combustion event based on the comparison.

Willi, Martin L. (Dunlap, IL); Fiveland, Scott B. (Metamora, IL); Montgomery, David T. (Edelstein, IL); Gong, Weidong (Dunlap, IL)

2012-04-03T23:59:59.000Z

285

Timeline Variability The Variability of Binding Time of Variation Points  

E-Print Network [OSTI]

Eelco Visser Technical Report UU-CS-2003-052 Institute of Information and Computing Sciences Utrecht-3275 Address: Eelco Dolstra Utrecht University, P.O. Box 80089, 3508 TB Utrecht, The Netherlands eelco@cs.uu.nl Gert Florijn SERC, P.O. Box 424, 3500 AK Utrecht, The Netherlands florijn@serc.nl Eelco Visser Utrecht

Utrecht, Universiteit

286

Technology Reinvestment Program/Advanced ``Zero Emission'' Control Valve (Phase II)  

SciTech Connect (OSTI)

The objectives of this effort are to determine, develop and demonstrate the feasibility of significantly reducing the cost and expanding the applications for a family of Advanced Zero Emissions Control Valves that meets the fugitive emissions requirements of the 1990 Amendments to the Clean Air Act. This program is a direct technology spin-off from the valve technology that is critical to the US Navy's Nuclear Powered Fleet. These zero emissions valves will allow the Hydrocarbon and Chemical Processing Industries, etc., to maintain their competitiveness and still meet environmental and safety requirements. Phase 2 is directed at refining the basic technologies developed during Phase 1 so that they can be more readily selected and utilized by the target market. In addition to various necessary certifications, the project will develop a full featured digital controller with ``smart valve'' growth capability, expanding valve sizes/applications and identifying valve materials to permit applications in severe operational environments.

J. Napoleon

1998-12-01T23:59:59.000Z

287

Development of a thyristor valve for next generation 500kV HVDC transmission systems  

SciTech Connect (OSTI)

A high voltage thyristor valve is the basic component of an HVDC transmission system. Development of a 500kV valve for next generation HVDC transmission systems is described. First, the power loss of the valve is analyzed to decide a reasonable wafer size for the light triggered thyristor. From these results, a six inch diameter wafer size is selected. The light triggered thyristor, with ratings of 8kV and 3.5kA, is developed using the six inch wafer. The designing of the valve employing the thyristor and test results with the prototype valve prove that a 500kV valve can be realized by the design method.

Hasegawa, T. [Kansai Electric Power Co., Inc., Osaka (Japan)] [Kansai Electric Power Co., Inc., Osaka (Japan); Yamaji, K. [Shikoku Electric Power Co., Inc., Takamatsu (Japan)] [Shikoku Electric Power Co., Inc., Takamatsu (Japan); Irokawa, H. [Electric Power Development Co., Ltd., Tokyo (Japan)] [Electric Power Development Co., Ltd., Tokyo (Japan); Shirahama, H.; Tanaka, C.; Akabane, K.

1996-10-01T23:59:59.000Z

288

Computations of high-pressure steam flow in the turbine bypass valve  

SciTech Connect (OSTI)

The objective of the present study is to investigate the steam flow behavior through the high-pressure turbine bypass valve. Efforts have mainly been directed at investigating the process of steam flow and property variations aforementioned bypass valve as well as to obtain correlations between the flow rate and the valve opening ratio. Modeling of the high-pressure turbulent steam flow was performed on a three-dimensional non-staggered grid system by employing the finite volume method and by solving the three-dimensional, turbulent, compressible Navier-Stokes, and energy equations. Through this research, numerous data have been acquired and analyzed. These efforts enable one to obtain a correlation data set for the valve opening versus flow rate coefficient of the valve. One of the significant accomplishments is to use the model presented here to further improve a design of a turbine bypass flow valve.

Amano, R.S.; Draxler, G.R.

1999-07-01T23:59:59.000Z

289

E-Print Network 3.0 - ahmed valve implantation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

delivery applications Summary: power, on demand valve. Previously, an implantable infusion pump system was inves- tigated... improved in order to power a series thermistor and...

290

E-Print Network 3.0 - aortic valve thickness Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

scaffold Summary: Tissue engineered aortic valves based on a knitted scaffold 12;CIP-DATA LIBRARY TECHNISCHE... UNIVERSITEIT EINDHOVEN Lieshout, Marjolein I. van Tissue...

291

E-Print Network 3.0 - aortic valve insertion Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

scaffold Summary: Tissue engineered aortic valves based on a knitted scaffold 12;CIP-DATA LIBRARY TECHNISCHE... UNIVERSITEIT EINDHOVEN Lieshout, Marjolein I. van Tissue...

292

E-Print Network 3.0 - aortic valve sclerosis Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

aortic valve disease... 21 ... Source: Simmons, Craig A. - Department of Mechanical and Industrial Engineering, University of Toronto Collection: Engineering ; Biology and...

293

NUPRO process vent/MCO check valve - prevent backflow from process vent into MCO  

SciTech Connect (OSTI)

NUPRO process vent/MCO check valve - prevent backflow from process vent into MCO CGI-SNF-D-30-3-P4-040.

VAN KATWIJK, C.

1999-07-01T23:59:59.000Z

294

E-Print Network 3.0 - aortic valve surgery Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Medicine ; Chemistry 2 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: A Computational Model of Aging and Calcification in the Aortic Heart...

295

E-Print Network 3.0 - aortic valve calcium Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

; Biology and Medicine 2 Inhibition of aortic wall calcification in bioprosthetic heart valves by ethanol pretreatment: Biochemical and Summary: Inhibition of aortic wall...

296

E-Print Network 3.0 - active infective valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: Non-invasive assessment of leaflet deformation and mechanical properties in heart valve tissue... -invasive assessment of leaflet deformation and mechanical properties...

297

E-Print Network 3.0 - autologous pulmonary valves Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ecole Polytechnique, Centre de mathmatiques Collection: Mathematics 2 Autologous Heart Valve Tissue Engineering CIP-DATA LIBRARY TECHNISCHE UNIVERSITEIT EINDHOVEN Summary:...

298

E-Print Network 3.0 - aortic valve implantation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Medicine ; Chemistry 3 Inhibition of aortic wall calcification in bioprosthetic heart valves by ethanol pretreatment: Biochemical and Summary: , Comparison of...

299

Means for positively seating a piezoceramic element in a piezoelectric valve during inlet gas injection  

DOE Patents [OSTI]

A piezoelectric valve in a gas delivery system includes a piezoceramic element bonded to a valve seal and disposed over a valve seat, and retained in position by an O-ring and a retainer; an insulating ball normally biased by a preload spring against the piezoceramic element; an inlet gas port positioned such that upon admission of inlet gas into the valve, the piezoceramic element is positively seated. The inlet gas port is located only on the side of the piezoceramic element opposite the seal. 3 figs.

Wright, K.E.

1994-08-23T23:59:59.000Z

300

Valve performance concept move from preventive to condition-oriented maintenance  

SciTech Connect (OSTI)

As a turnkey supplier of nuclear and fossil power plants, Siemens must pay attention in concentrating, maintaining, and developing the expertise in many areas such as system design, components, materials, quality assurance, and qualification testing within centralized organizations. In the company segment VALVES, Siemens/KWU is staffed with experienced professionals who have serviced the power plant industry for about 25 years. The valve engineers deal with all kinds of valve and actuator-related activities like design ratings, development, qualifications, and ongoing improvements. In this regard, the engineers are involved in nearly all actual problems and suggested solutions through continuing dialogues with utilities, authorities, and vendors of valves and actuators.

Zanner, G.; Kradepohl, P.

1996-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Means for positively seating a piezoceramic element in a piezoelectric valve during inlet gas injection  

DOE Patents [OSTI]

A piezoelectric valve in a gas delivery system includes a piezoceramic element bonded to a valve seal and disposed over a valve seat, and retained in position by an O-ring and a retainer; an insulating ball normally biased by a preload spring against the piezoceramic element; an inlet gas port positioned such that upon admission of inlet gas into the valve, the piezoceramic element is positively seated. The inlet gas port is located only on the side of the piezoceramic element opposite the seal.

Wright, Kenneth E. (Yardley, PA)

1994-01-01T23:59:59.000Z

302

E-Print Network 3.0 - activities addressing valve Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

recommendations for addressing cylinders which utilize these valves. The Problem Air Products and Chemicals, Inc... of potential hazards associated with two specific lots of...

303

Rotating drum variable depth sampler  

DOE Patents [OSTI]

A sampling device for collecting depth-specific samples in silt, sludge and granular media has three chambers separated by a pair of iris valves. Rotation of the middle chamber closes the valves and isolates a sample in a middle chamber.

Nance, Thomas A. (Aiken, SC); Steeper, Timothy J. (Trenton, SC)

2008-07-01T23:59:59.000Z

304

Use of duplex stainless steel castings in control valves  

SciTech Connect (OSTI)

Duplex stainless steels have enjoyed rapidly increasing popularity in recent years. For numerous reasons the availability of these alloys in the cast form has lagged behind the availability of the wrought form. Commercial demand for control valves in these alloys has driven development of needed information to move into production. A systematic approach was used to develop specifications, suppliers and weld procedures. Corrosion, stress corrosion cracking (SCC), sulfide stress cracking (SSC) and hardness results are also presented for several alloys including; CD3MN (UNS J92205), CD4MCu (UNS J93370) and CD7MCuN (cast UNS S32550).

Gossett, J.L. [Fisher Controls International, Inc., Marshalltown, IA (United States)

1996-07-01T23:59:59.000Z

305

Potential Viability of a Fast-Acting Micro-Solenoid Valve for Pulsed Detonation Fuel Injection  

E-Print Network [OSTI]

current (A) k spring constant (kg/s2 ) Ll flux leakage inductance (H) L(, x) non-linear coil inductance (H-load conditions, indicating the ability of spring- return micro-valves to function reliably at high frequencies) m mass of movable valve core and spring assembly (kg) n integer number of successive (positive

Texas at Arlington, University of

306

Journal of Biomechanics 34 (2001) 12791289 A nonlinear anisotropic model for porcine aortic heart valves  

E-Print Network [OSTI]

Journal of Biomechanics 34 (2001) 1279­1289 A nonlinear anisotropic model for porcine aortic heart finite element model for porcine heart valves. The model is based on the uniaxial experimental data of porcine aortic heart valve leaflet and the properties of nonlinear composite material. A finite element

Luo, Xiaoyu

307

Microfluidic very large scale integration (mVLSI) with integrated micromechanical valves{  

E-Print Network [OSTI]

Microfluidic very large scale integration (mVLSI) with integrated micromechanical valves{ Ismail40258k Microfluidic chips with a high density of control elements are required to improve device and accessible high-density microfluidic chips, we have fabricated a monolithic PDMS valve architecture

Quake, Stephen R.

308

Thermal Shock Effects Modeling on a Globe Valve Body-Bonnet Bolted Flange Joint  

E-Print Network [OSTI]

and are sources of issues to suppliers and users. This is also the case when it comes to valve reliability. In French nuclear industry, EDF used to work closely with valve suppliers to ensure the reliability. Thus of qualification was created in the beginning of the French nuclear Pressurized Water Reactors (PWR) industry

Paris-Sud XI, Université de

309

Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule  

E-Print Network [OSTI]

1 Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule M.Dohlus,H.-P.Wedekind,K.Zapfe DeutschesElektronenSynchrotron Notkestr.85,D-22603Hamburg,Germany Abstract The beam pipe of the TESLA valves with spring type rf-shield which are presently used in the linac of the TESLA Test Facility

310

Rendering the Electromechanical Valve Actuator Globally Asymptotically Stable Katherine S. Peterson and Anna G. Stefanopoulou*  

E-Print Network [OSTI]

Rendering the Electromechanical Valve Actuator Globally Asymptotically Stable Katherine S. Peterson on Sontag's feedback to render the electromechanical valve actuator (EVA) globally asymptotically stable on a linearized plant model. Here, we demonstrate and prove that our controller renders the system GAS without any

Sontag, Eduardo

311

The superconducting spin valve and triplet superconductivity I.A. Garifullin a,n  

E-Print Network [OSTI]

The superconducting spin valve and triplet superconductivity I.A. Garifullin a,n , P.V. Leksin s t r a c t A review of our recent results on the spin valve effect is presented. We have used coefficient DF and the exchange splitting I of the conduction band in the F layer [1]. For pure Fe the value

Fominov, Yakov

312

Measurement Of The Fluid Flow Load On A Globe Valve Stem Under Various Cavitation  

E-Print Network [OSTI]

Measurement Of The Fluid Flow Load On A Globe Valve Stem Under Various Cavitation Conditions)" #12;Measurement Of The Fluid Flow Load On A Globe Valve Stem Under Various Cavitation Conditions, cavitation, fluid flow load, CFD. Abstract: The evaluation of fluid forces on the stem is important for wear

Paris-Sud XI, Université de

313

Proceedings of the 2nd symposium on valves for coal conversion and utilization  

SciTech Connect (OSTI)

The 2nd symposium on valves for coal conversion and utilization was held October 15 to 17, 1980. It was sponsored by the US Department of Energy, Morgantown Energy Technology Center, in cooperation with the Valve Manufacturers Association. Seventeen papers have been entered individually into EDB and ERA. (LTN)

Maxfield, D.A. (ed.)

1981-01-01T23:59:59.000Z

314

Condition monitoring of motor-operated valves in nuclear power plants Pierre Granjon  

E-Print Network [OSTI]

Condition monitoring of motor-operated valves in nuclear power plants Pierre Granjon Gipsa of nuclear power plants. Unfortunately, today's policies present a major drawback. Indeed, these monitoring safety constraints: nuclear power plants. Key components of such systems are motor-operated valves (MOVs

Boyer, Edmond

315

Department of Mechanical and Nuclear Engineering Spring 2012 Electro-Mechanically Actuated Trip and Throttle Valve  

E-Print Network [OSTI]

a special type of fail-safe valve for steam turbines. This valve closes rapidly to stop steam flow into a turbine, during emergency situations, to prevent injury and damage to the turbine. Some steam turbine engineers from both Exlar and Dresser-Rand to complete component and material selection for the final design

Demirel, Melik C.

316

Percutaneous Valve Replacement: Significance of Different Delivery Systems In Vitro and In Vivo  

SciTech Connect (OSTI)

Background and purpose. Percutaneous heart valve replacement is an exciting growing field in cardiovascular medicine yet still with some major problems. Only sophisticated improvement of the instruments could make it a real alternative to conventional surgery. Therefore, the aim of this study was to evaluate different delivery devices for percutaneous heart valve replacement in vitro and in vivo. Methods. A catheter prototype designed by our group, and two commercially available devices for the delivery of esophageal stents and aortic endoprostheses, were tested. After in vitro experiments, an ovine animal model of transfemoral pulmonary valve implantation was established using biological valved self-expanding stents. Only the delivery device for aortic endografts (Medtronic, Talent, Santa Rosa, CA, USA) allowed fast in vitro procedures without material fatigue. This device was chosen for the in vivo tests. Results. Technical success was achieved in 9 of 10 animals (90%). One animal died after perforation of the ventricular wall. Orthotopic pulmonary placement was performed in 6 animals and intentional supravalvular valved stent placement in 3 animals. Conclusions. An adequate in vitro model for this evolving field of interventional heart valve replacement is presented. Furthermore, the present study pinpoints the key characteristics that are mandatory for a delivery system in percutaneous pulmonary valve implantation. With regard to the delivery device's ductility observed during this 'venous' study, an approach to transfemoral aortic valve implantation seems feasible.

Attmann, Tim; Lutter, Georg, E-mail: lutter@kielheart.uni-kiel.de; Quaden, Rene [Christian Albrechts University of Kiel, Department of Cardiovascular Surgery, School of Medicine (Germany); Jahnke, Thomas [Christian Albrechts University of Kiel, Department of Radiology, School of Medicine (Germany); Rumberg, Kristin; Cremer, Jochen [Christian Albrechts University of Kiel, Department of Cardiovascular Surgery, School of Medicine (Germany); Muller-Hulsbeck, Stefan [Christian Albrechts University of Kiel, Department of Radiology, School of Medicine (Germany)

2006-06-15T23:59:59.000Z

317

Valve characterization to implement feed-forward control of hydraulically actuated joints  

E-Print Network [OSTI]

This thesis characterizes the flow behavior of a Hydraforce SP08-47CL valve given a specific pulse-width modulation (pwm) duty cycle. With a description of valve behavior, a feed-forward term can be implemented in the ...

Carey, Abby (Abby M.)

2008-01-01T23:59:59.000Z

318

Fluid-driven reciprocating apparatus and valving for controlling same  

DOE Patents [OSTI]

A control valve assembly for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. One embodiment of the invention utilized two pairs of fluid-driven free-piston devices whereby a bipropellant liquid propulsion system may be operated, so as to provide continuous flow of both fuel and oxidizer liquids when used in rocket applications, for example.

Whitehead, John C. (Davis, CA); Toews, Hans G. (East Aurora, NY)

1993-01-01T23:59:59.000Z

319

Two-phase flow characteristics in multiple orifice valves  

SciTech Connect (OSTI)

This work presents an experimental investigation on the characteristics of two-phase flow through multiple orifice valve (MOV), including frictional pressure drop and void fraction. Experiments were carried out using an MOV with three different sets of discs with throat thickness-diameter ratios (s/d) of 1.41, 1.66 and 2.21. Tests were run with air and water flow rates ranging between 1.0 and 3.0 m{sup 3}/h, respectively. The two-phase flow patterns established for the experiment were bubbly and slug. Two-phase frictional multipliers, frictional pressure drop and void fraction were analyzed. The determined two-phase multipliers were compared against existing correlations for gas-liquid flows. None of the correlations tested proved capable of predicting the experimental results. The large discrepancy between predicted and measured values points at the role played by valve throat geometry and thickness-diameter ratio in the hydrodynamics of two-phase flow through MOVs. A modification to the constants in the two-phase multiplier equation used for pipe flow fitted the experimental data. A comparison between computed frictional pressure drop, calculated with the modified two-phase multiplier equation and measured pressure drop yielded better agreement, with less than 20% error. (author)

Alimonti, Claudio [Sapienza University of Rome, Department ICMA, Via Eudossiana 18, 00184 Roma (Italy); Falcone, Gioia; Bello, Oladele [The Harold Vance Department of Petroleum Engineering, Texas A and M University, 3116 TAMU, Richardson Building, College Station, TX 77843 (United States)

2010-11-15T23:59:59.000Z

320

Fueling U.S. Light Duty Diesel Vehicles  

Broader source: Energy.gov (indexed) [DOE]

- Cylinder deactivation - Variable valve timing & lift - Direct injectionlean burn - Turbo chargingdownsizing - Integrated starter generators - Low temperature combustion *...

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Interdiffusion in CoFeCu multilayers and its application to spin-valve structures for data storage  

E-Print Network [OSTI]

, the interdiffusion coefficients for all layers in the spin valve have to be determined. For diffusion drivenInterdiffusion in CoFe?Cu multilayers and its application to spin-valve structures for data storage, Pennsylvania 15213-3890 Received 13 February 2003; accepted 30 April 2003 Spin-valve structures might

Laughlin, David E.

322

IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 15, NO. 6, NOVEMBER 2007 1065 Robust Optimal Design of Unstable Valves  

E-Print Network [OSTI]

and outer radii of the valve chamber; and 3) the nonmetering orifice momentum flux coefficient which Design of Unstable Valves QingHui Yuan, Member, IEEE, and Perry Y. Li, Member, IEEE Abstract--This paper of electrohydraulic valves. Currently, limitations of solenoid actua- tors have prevented single stage

Li, Perry Y.

323

Percutaneous Transcatheter One-Step Mechanical Aortic Disc Valve Prosthesis Implantation: A Preliminary Feasibility Study in Swine  

SciTech Connect (OSTI)

Purpose. To evaluate the feasibility of one-step implantation of a new type of stent-based mechanical aortic disc valve prosthesis (MADVP) above and across the native aortic valve and its short-term function in swine with both functional and dysfunctional native valves. Methods. The MADVP consisted of a folding disc valve made of silicone elastomer attached to either a nitinol Z-stent (Z model) or a nitinol cross-braided stent (SX model). Implantation of 10 MADVPs (6 Z and 4 SX models) was attempted in 10 swine: 4 (2 Z and 2 SX models) with a functional native valve and 6 (4 Z and 2 SX models) with aortic regurgitation induced either by intentional valve injury or by MADVP placement across the native valve. MADVP function was observed for up to 3 hr after implantation. Results. MADVP implantation was successful in 9 swine. One animal died of induced massive regurgitation prior to implantation. Four MADVPs implanted above functioning native valves exhibited good function. In 5 swine with regurgitation, MADVP implantation corrected the induced native valve dysfunction and the device's continuous good function was observed in 4 animals. One MADVP (SX model) placed across native valve gradually migrated into the left ventricle. Conclusion. The tested MADVP can be implanted above and across the native valve in a one-step procedure and can replace the function of the regurgitating native valve. Further technical development and testing are warranted, preferably with a manufactured MADVP.

Sochman, Jan [Institute for Clinical and Experimental Medicine, Intensive Care Unit, Clinic of Cardiology (Czech Republic)], E-mail: jan.sochman@medicon.cz; Peregrin, Jan H.; Rocek, Miloslav [Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology (Czech Republic); Timmermans, Hans A.; Pavcnik, Dusan; Roesch, Josef [Oregon Health and Sciences University, Dotter Interventional Institute (United States)

2006-02-15T23:59:59.000Z

324

Flow Characteristics Analysis of Widows' Creek Type Control Valve for Steam Turbine Control  

SciTech Connect (OSTI)

The steam turbine converts the kinetic energy of steam to mechanical energy of rotor blades in the power conversion system of fossil and nuclear power plants. The electric output from the generator of which the rotor is coupled with that of the steam turbine depends on the rotation velocity of the steam turbine bucket. The rotation velocity is proportional to the mass flow rate of steam entering the steam turbine through valves and nozzles. Thus, it is very important to control the steam mass flow rate for the load following operation of power plants. Among various valves that control the steam turbine, the control valve is most significant. The steam flow rate is determined by the area formed by the stem disk and the seat of the control valve. While the ideal control valve linearly controls the steam mass flow rate with its stem lift, the real control valve has various flow characteristic curves pursuant to the stem lift type. Thus, flow characteristic curves are needed to precisely design the control valves manufactured for the operating conditions of nuclear power plants. OMEGA (Optimized Multidimensional Experiment Geometric Apparatus) was built to experimentally study the flow characteristics of steam flowing inside the control valve. The Widows' Creek type control valve was selected for reference. Air was selected as the working fluid in the OMEGA loop to exclude the condensation effect in this simplified approach. Flow characteristic curves were plotted by calculating the ratio of the measured mass flow rate versus the theoretical mass flow rate of the air. The flow characteristic curves are expected to be utilized to accurately design and operate the control valve for fossil as well as nuclear plants. (authors)

Yoo, Yong H.; Sohn, Myoung S.; Suh, Kune Y. [PHILOSOPHIA, Inc., Seoul National University, San 56-1 Sillim-dong, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)

2006-07-01T23:59:59.000Z

325

Coal slurry letdown valve-concept test phase. Final report  

SciTech Connect (OSTI)

The results of the concept test phase of a novel pressure letdown device indicate usefulness of the concept. The device, using staged letdown, was designed to minimize erosion damage by minimizing slurry velocities through the pressure restrictions. Tests were performed on air, steam/water and a coal slurry with a flashing component. Two valve sizes were used. Based on the results of these tests, the following conclusions were drawn: (1) the basic operating principle of designing for a constant velocity through the orifice restrictions is correct; (2) multiphase pressure letdown can be modeled; (3) temperature profiles are predictable; and (4) erosion in three-phase flow is a complex phenomenon. Recommendations for further work on the device include: (1) development of a controllable device; (2) correlation of further test data; and (3) study of flow regimes where erosion is minimized. 9 refs., 48 figs., 6 tabs.

Collins, E.R. Jr.; Suitor, J.W.

1984-01-01T23:59:59.000Z

326

Electromagnetic valve for controlling the flow of molten, magnetic material  

DOE Patents [OSTI]

An electromagnetic valve for controlling the flow of molten, magnetic material is provided, which comprises an induction coil for generating a magnetic field in response to an applied alternating electrical current, a housing, and a refractory composite nozzle. The nozzle is comprised of an inner sleeve composed of an erosion resistant refractory material (e.g., a zirconia ceramic) through which molten, magnetic metal flows, a refractory outer shell, and an intermediate compressible refractory material, e.g., unset, high alumina, thermosetting mortar. The compressible refractory material is sandwiched between the inner sleeve and outer shell, and absorbs differential expansion stresses that develop within the nozzle due to extreme thermal gradients. The sandwiched layer of compressible refractory material prevents destructive cracks from developing in the refractory outer shell. 5 figs.

Richter, T.

1998-06-16T23:59:59.000Z

327

Configuration and temperature dependence of magnetic damping in spin valves  

SciTech Connect (OSTI)

Using vector-analyzer ferromagnetic resonance, we have studied the microwave susceptibility of a Py/Co/Cu/Co/MnIr spin valve over a large temperature range (5-450 K) and as a function of the magnetic configuration. An effective magnetization and Gilbert damping constant of 1.1 T and 0.021, respectively, are found for the permalloy free layer, with no discernible variation in temperature observed for either quantities. In contrast, the pinned layer magnetization is reduced by heating, and the exchange bias collapses near a temperature of 450 K. The ferromagnetic resonance linewidth of the free layer increases by 500 MHz when the layer magnetizations are aligned in antiparallel, which is attributed to a configuration-dependent contribution to the damping from spin pumping effects.

Joyeux, X.; Devolder, T.; Kim, Joo-Von; Gomez de la Torre, Y.; Eimer, S.; Chappert, C. [Institut d'Electronique Fondamentale, University Paris-Sud, 91405 Orsay (France); UMR8622, CNRS, University Paris-Sud, 91405 Orsay (France)

2011-09-15T23:59:59.000Z

328

Strength and fatigue of NT551 silicon nitride and NT551 diesel exhaust valves  

SciTech Connect (OSTI)

The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOE/OTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. The motivations behind using silicon nitride (Si{sub 3}N{sub 4}) as an exhaust valve for a diesel engine are presented in this section. There are several economic factors that have encouraged the design and implementation of ceramic components for internal combustion (IC) engines. The reasons for selecting the diesel engine valve for this are also presented.

Andrews, M.J.; Werezczak, A.A.; Kirkland, T.P.; Breder, K.

2000-02-01T23:59:59.000Z

329

Jet-controlled freeze valve for use in a glass melter  

DOE Patents [OSTI]

A drain valve for use in furnace for the melting of thermoplastic material is disclosed. The furnace includes a drain cavity formed in its bottom for withdrawing a flow of thermoplastic material. The drain valve includes a flow member which include a flow tube having an inlet and outlet for the material, and coaxially disposed concentric tubular members defining annuli surrounding the flow tube. The tubular members include heating and cooling means for the flow tube. The drain valve can also be used in a furnace of glass melting that includes a drain cavity for withdrawing molten glass from the furnace.

Routt, K.R.

1985-07-29T23:59:59.000Z

330

Proceedings of the symposium on inservice testing of pumps and valves  

SciTech Connect (OSTI)

The 1990 Symposium on Inservice Testing of Pumps and Valves, jointly sponsored by the Board on Nuclear Codes and Standards of the American Society of Mechanical Engineers and by the Nuclear Regulatory Commission, provided a forum for the discussion of current programs and methods for inservice testing at nuclear power plants. The symposium also provided an opportunity to discuss the need to improve inservice testing in order to ensure the reliable performance of pumps and valves. The participation of industry representatives, regulators, and consultants resulted in the discussion of a broad spectrum of ideas and perspectives regarding the improvement of inservice testing of pumps and valves at nuclear power plants.

Not Available

1990-10-01T23:59:59.000Z

331

An analysis of the relationship of heart sound time intervals to respiratory sinus arrhythmia  

E-Print Network [OSTI]

to be close to the clinically significant left ventricular ejection time (LVET). These results were obtained in a laboratory setting. Recording heart sounds at the trachea was not easy. The heart sound signal was not very stable. In order for a useful... VALVE R - LEFT VENTRICLE Figure 1. Crossectional view of the heart showing the four chambers and the four valves. l20 X IOO E E 80 oI 60 In 40 Aornc volve opens PROTODIASTOLE EJECTION~ COIJTRACTION~ I, r Aortic valve closes r ISOMETRIC...

Schorsch, Eric Todd

1987-01-01T23:59:59.000Z

332

HIGH-FREQUENCY MAGNETOCAPACITANCE EFFECT IN ORGANIC SPIN VALVE WITH A  

E-Print Network [OSTI]

HIGH-FREQUENCY MAGNETOCAPACITANCE EFFECT IN ORGANIC SPIN VALVE WITH A 3,4,9,10-PERYLENE Institute of Atomic and Molecular Sciences Academia Sinica, 10617 Taipei, Taiwan *mtlin@phys.ntu

Lin, Minn-Tsong

333

Classification of heart valve single leg separations from acoustic clinical measurements  

SciTech Connect (OSTI)

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

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

1994-05-01T23:59:59.000Z

334

E-Print Network 3.0 - ahmed glaucoma valve Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Saati MD, Ronalee Lo PhD, Po-Ying Li PhD, Ellis Meng PhD, Rohit Varma MD MPH, AND Mark S. Humayun MD Summary: and morphology after Ahmed glaucoma valve implantation during...

335

Rankine cycle condenser pressure control using an energy conversion device bypass valve  

DOE Patents [OSTI]

The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

2014-04-01T23:59:59.000Z

336

Percutaneous aortic valve replacement in a re-animated postmortem heart  

E-Print Network [OSTI]

transcatheter implantation of heart valve prosthesis for thein apex of post-mortem heart (lower view). B C A Figure 5A.descending aorta in lambs. Eur Heart J. 2002;23:1045-49. 5.

White, Jennifer; Sun, Amy; Killien, Lauren; Evangelista, Dennis

2006-01-01T23:59:59.000Z

337

VALVE FUNNEL SPRING PIN PRESS PERFORMANCE AND FUNCTIONAL REQUIREMENTS EVALUATION FOR SPECIAL TOOLS AND EQUIPMENT  

SciTech Connect (OSTI)

This evaluation allows use of the valve funnel spring pin press and describes appropriate handling instructions for the tool. The engineering evaluation is required for operations and field use of special tools and equipment.

WITHERSPOON JT

2009-12-30T23:59:59.000Z

338

Volume 4 Issue 2 www.nasa.gov/centers/stennis February 2009 Stennis tests shuttle valves  

E-Print Network [OSTI]

hydrogen tubing. The call went out to three centers to begin testing aspects of the valve. Engineers the Stennis team faced during the original construction, or during the crossover to successfully execute

339

E-Print Network 3.0 - aortic valve substitution Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

<< < 1 2 3 4 5 > >> 1 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: A Computational Model of Aging and Calcification in the Aortic Heart...

340

E-Print Network 3.0 - aortic valve calcification Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

<< < 1 2 3 4 5 > >> 1 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: A Computational Model of Aging and Calcification in the Aortic Heart...

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

E-Print Network 3.0 - aortic valve replacement Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

<< < 1 2 3 4 5 > >> 1 A Computational Model of Aging and Calcification in the Aortic Heart Valve Summary: A Computational Model of Aging and Calcification in the Aortic Heart...

342

E-Print Network 3.0 - aortic valve endocarditis Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

are aortic valve disease, present in 12 to 30 percent of cases, and congenital heart disease... in detection of IE.24 TEE is especially important for patients with aortic...

343

Design and sizing of electromagnetic linear actuators for valve applications  

E-Print Network [OSTI]

, a description of the design and sizing of variable reluctance or permanent magnet devices is given. The main, concerning magnetic saturation, the section of this shaft will have to be greater than a minimal value. So qualities of each structure are enhanced. Keywords: Linear motion actuator, variable reluctance, permanent

Paris-Sud XI, Université de

344

Characteristics of cyclic heat release variability in the transition from spark ignition to HCCI in a gasoline engine  

SciTech Connect (OSTI)

We study selected examples of previously published cyclic heat-release measurements from a single-cylinder gasoline engine as stepwise valve timing adjustments were made to shift from spark ignited (SI) combustion to homogeneous charge compression ignition (HCCI). Wavelet analysis of the time series, combined with conventional statistics and multifractal analysis, revealed previously undocumented features in the combustion variability as the shift occurred. In the spark-ignition combustion mode, the heat-release variations were very small in amplitude and exhibited more persistent low-frequency oscillations with intermittent high-frequency bursts. In the HCCI combustion mode, the amplitude of the heat-release variations again was small and involved mainly low-frequency oscillations. At intermediate states between SI and HCCI, a wide range of very large-amplitude oscillations occurred, including both persistent low-frequency periodicities and intermittent high-frequency bursts. It appears from these results that real-time wavelet decomposition of engine cylinder pressure measurements may be useful for on-board tracking of SI HCCI combustion regime shifts.

Sen, Asok K [Indiana University; Litak, Grzegorz [Technical University of Lublin; Edwards, Kevin Dean [ORNL; FINNEY, Charles E A [ORNL; Daw, C Stuart [ORNL; Wagner, Robert M [ORNL

2011-01-01T23:59:59.000Z

345

Automated high-throughput flow-through real-time diagnostic system  

DOE Patents [OSTI]

An automated real-time flow-through system capable of processing multiple samples in an asynchronous, simultaneous, and parallel fashion for nucleic acid extraction and purification, followed by assay assembly, genetic amplification, multiplex detection, analysis, and decontamination. The system is able to hold and access an unlimited number of fluorescent reagents that may be used to screen samples for the presence of specific sequences. The apparatus works by associating extracted and purified sample with a series of reagent plugs that have been formed in a flow channel and delivered to a flow-through real-time amplification detector that has a multiplicity of optical windows, to which the sample-reagent plugs are placed in an operative position. The diagnostic apparatus includes sample multi-position valves, a master sample multi-position valve, a master reagent multi-position valve, reagent multi-position valves, and an optical amplification/detection system.

Regan, John Frederick

2012-10-30T23:59:59.000Z

346

A real time neural energy management strategy for a hybrid pneumatic engine  

E-Print Network [OSTI]

Minimization Strategy (ECMS) and equivalent to a Variable Penalty Coefficient Strategy with Driving Pattern to the combustion chamber by a supplemen- tary pipe and an additional charging valve (see Figure 1). This allows by Dynamic Programming, the basic Causal Strategy, the different Penalty Coefficient strategies, in- cluding

Paris-Sud XI, Université de

347

Optimal Design of a High-Speed On/Off Valve for a Hydraulic Hybrid Vehicle Application  

E-Print Network [OSTI]

Coefficient 0.6 same none eq Fluid Bulk Modulus 3.7 x 108 1.2 x 109 Pa Pc Check Valve Cracking Pressure 3.2 NOptimal Design of a High-Speed On/Off Valve for a Hydraulic Hybrid Vehicle Application Michael of Minnesota, Minneapolis, MN, USA ABSTRACT Control of hydraulic systems using high-speed on/off valves has

Li, Perry Y.

348

Solar Dynamics Observatory/ Extreme Ultraviolet Variability Experiment  

E-Print Network [OSTI]

Solar Dynamics Observatory/ EVE Extreme Ultraviolet Variability Experiment Frequently Asked and model solar extreme ultraviolet irradiance variations due to solar flares, solar rotation, and solar and structure of the Sun. What is solar variability? Solar radiation varies on all time scales ranging from

Mojzsis, Stephen J.

349

The Galex Ultraviolet Variability (GUVV) Catalog  

E-Print Network [OSTI]

We present Version 1.0 of the NASA Galaxy Evolution Explorer (GALEX) ultraviolet variability catalog (GUVV) that contains information on 84 time-variable and transient sources gained with simultaneous near and far ultraviolet photometric observations. These time-variable sources were serendipitously revealed in the various 1.2 degree star fields currently being surveyed by the GALEX satellite in two ultraviolet bands (NUV 1750-2750A, FUV 1350-1750A) with limiting AB magnitudes of 23-25. The largest-amplitude variable objects presently detected by GALEX are M-dwarf flare stars, which can brighten by 5-10 mag in both the NUV and FUV bands during short duration (< 500s) outbursts. Other types of large-amplitude ultraviolet variable objects include ab-type RR Lyrae stars, which can vary periodically by 2-5mag in the GALEX FUV band. This first GUVV catalog lists galactic positions and possible source identifications in order to provide the astronomical community with a list of time-variable objects that can now be repeatedly observed at other wavelengths. We expect the total number of time-variable source detections to increase as the GALEX mission progresses, such that later version numbers of the GUVV catalog will contain substantially more variable sources.

Barry Y. Welsh; Jonathan M. Wheatley; Kenneth Heafield; Mark Seibert; Stanley E. Browne; Samir Salim; R. Michael Rich; Tom A. Barlow; Luciana Bianchi; Yong-Ik Byun; Jose Donas; Karl Forster; Peter G. Friedman; Timothy M. Heckman; Patrick N. Jelinsky; Young-Wook Lee; Barry F. Madore; Roger F. Malina; D. Christopher Martin; Bruno Milliard; Patrick Morrissey; Susan G. Neff; David Schiminovich; Oswald H. W. Siegmund; Todd Small; Alex S. Szalay; Ted K. Wyder

2005-04-21T23:59:59.000Z

350

Processing of prosthetic heart valve sounds for single leg separation classification  

SciTech Connect (OSTI)

Efforts are concentrated on the sounds corresponding to the heart valve opening cycle. Valve opening and closing acoustics present additional information about the outlet strut condition---the structural component implicated in valve failure. The importance of the opening sound for single leg separation detection/classification is based on the fact that as the valve opens, the disk passively hits the outlet strut. The opening sounds thus yield direct information about outlet strut condition with minimal amount of disturbance caused by the energy radiated from the disk. Hence the opening sound is a very desirable acoustic signal to extract. Unfortunately, the opening sounds have much lower signal levels relative to the closing sounds and therefore noise plays a more significant role than during the closing event. Because of this it is necessary to screen the sounds for outliers in order to insure a high sensitivity of classification. Because of the sharp resonances appearing in the corresponding spectrum, a parametric processing approach is developed based on an autoregressive model which was selected to characterize the sounds emitted by the Bjork--Shiley convexo--concave (BSCC) valve during opening cycle. First the basic signals and the extraction process used to create an ensemble of heart valve sounds are briefly discussed. Next, a {ital beat} {ital monitor} capable of rejecting beats that fail to meet an acceptance criteria based on their spectral content is developed. Various approaches that have been utilized to enhance the screened data and produce a reliable {ital heart} {ital valve} {ital spectrogram} which displays the individual sounds (power) as a function of beat number and temporal frequency are discussed. Once estimated, the spectrogram and associated parameters are used to develop features supplied to the various classification schemes. Finally, future work aimed at even further signal enhancement and improved classifier performance is discussed.

Candy, J.V.; Jones, H.E. [University of California, Lawrence Livermore National Laboratory, P.O. Box 808, L-495, Livermore, California 94550 (United States)

1995-06-01T23:59:59.000Z

351

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

E-Print Network [OSTI]

Compression Ignition (HCCI) engines high level of EGR can be used to indirectly control combustion initiation and HCCI engines [7, 10]. Conventional external EGR (eEGR), relies on a pressure drop from exhaust manifold

Stefanopoulou, Anna

352

Multi objective optimisation of an electromagnetic valve actuator Nicolas BELLEGARDE, Jean-Claude VANNIER, Philippe DESSANTE, Pierre VIDAL  

E-Print Network [OSTI]

Multi objective optimisation of an electromagnetic valve actuator Nicolas BELLEGARDE, Jean, weight, volume. 1. Notations a Thickness of the mobile part (mm) Slot's coefficient of occupation b

Paris-Sud XI, Université de

353

Benchmarking Variable Cost Performance in an Industrial Power Plant  

E-Print Network [OSTI]

One of the most perplexing problems for industrial power plants committed to improving competitiveness is measuring variable cost performance over time. Because variable costs like fuel and electricity represent the overwhelming majority of power...

Kane, J. F.; Bailey, W. F.

354

HCCI Load Expansion Opportunities Using a Fully Variable HVA Research Engine to Guide Developments of a Production Intent Cam-Based VVA Engine: The Low Load Limit  

SciTech Connect (OSTI)

While the potential emissions and efficiency benefits of HCCI combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on identifying challenges and opportunities associated with a production intent cam-based variable valve actuation (VVA) system on a multi-cylinder engine in comparison to a fully flexible, naturally aspirated, hydraulic valve actuation (HVA) system on a single-cylinder engine, with both platforms sharing the same GDI fueling system and engine geometry. The multi-cylinder production intent VVA system uses a 2-step cam technology with wide authority cam phasing, allowing adjustments to be made to the negative valve overlap (NVO) duration but not the valve opening durations. On the single cylinder HVA engine, the valve opening duration and lift are variable in addition to the NVO duration. The content of this paper is limited to the low-medium operating load region at 2000rpm. Using different injection strategies, including the NVO pilot injection approach, the single-cylinder engine is operated over a load range from 160-390 kPa net IMEP at 2000 rpm. Changes to valve opening duration on the single-cylinder HVA engine illustrate opportunities for load expansion and efficiency improvement at certain conditions. For instance, the low load limit can be extended on the HVA engine by reducing breathing and operating closer to a stoichiometric air fuel ratio (AFR) by using valve deactivation. The naturally aspirated engine used here without external EGR confirmed that as operating load increases the emissions of NOx increases due to combustion temperature. NOx emissions are found to be one limitation to the maximum load limitation, the other being high pressure rise rate. It is found that the configuration of the production intent cam-based system represents a good compromise between valve lift and duration in the low to medium load region. Changing the extent of charge motion and breathing via valve deactivation prove beneficial at moderating the pressure rise rate and combustion stability and extending the low load limit at 2000rpm on the HVA engine. It also confirms that strategies using a pilot fuel injection are beneficial at low operating loads but that as operating load is increased, the benefits of multiple injection diminish to the point where a single injection offers the best performance.

Weall, Adam J [ORNL; Szybist, James P [ORNL; Edwards, Kevin Dean [ORNL; Foster, Matthew [Delphi; Confer, Keith [Delphi; Moore, Wayne [Delphi

2012-01-01T23:59:59.000Z

355

HCCI Load Expansion Opportunities using a Fully Variable HVA Research Engine to Guide Development of a Production Intent Cam-based VVA Engine: The Low Load Limit  

SciTech Connect (OSTI)

While the potential emissions and efficiency benefits of HCCI combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on identifying challenges and opportunities associated with a production intent cam-based variable valve actuation (VVA) system on a multi-cylinder engine in comparison to a fully flexible, naturally aspirated, hydraulic valve actuation (HVA) system on a single-cylinder engine, with both platforms sharing the same GDI fueling system and engine geometry. The multi-cylinder production intent VVA system uses a 2-step cam technology with wide authority cam phasing, allowing adjustments to be made to the negative valve overlap (NVO) duration but not the valve opening durations. On the single cylinder HVA engine, the valve opening duration and lift are variable in addition to the NVO duration. The content of this paper is limited to the low-medium operating load region at 2000rpm. Using different injection strategies, including the NVO pilot injection approach, the single-cylinder engine is operated over a load range from 160-390 kPa net IMEP at 2000 rpm. Changes to valve opening duration on the single-cylinder HVA engine illustrate opportunities for load expansion and efficiency improvement at certain conditions. For instance, the low load limit can be extended on the HVA engine by reducing breathing and operating closer to a stoichiometric air fuel ratio (AFR) by using valve deactivation. The naturally aspirated engine used here without external EGR confirmed that as operating load increases the emissions of NOx increases due to combustion temperature. NOx emissions are found to be one limitation to the maximum load limitation, the other being high pressure rise rate. It is found that the configuration of the production intent cam-based system represents a good compromise between valve lift and duration in the low to medium load region. Changing the extent of charge motion and breathing via valve deactivation prove beneficial at moderating the pressure rise rate and combustion stability and extending the low load limit at 2000rpm on the HVA engine. It also confirms that strategies using a pilot fuel injection are beneficial at low operating loads but that as operating load is increased, the benefits of multiple injection diminish to the point where a single injection offers the best performance.

Weall, Adam J [ORNL] [ORNL; Szybist, James P [ORNL] [ORNL; Edwards, Kevin Dean [ORNL] [ORNL; Foster, Matthew [Delphi] [Delphi; Confer, Keith [Delphi] [Delphi; Moore, Wayne [Delphi] [Delphi

2012-01-01T23:59:59.000Z

356

Uncertainty Analysis for a Virtual Flow Meter Using an Air-Handling Unit Chilled Water Valve  

SciTech Connect (OSTI)

A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the probability of error in the measurements is significantly greater than for conventionally manufactured flow meters. In this paper, mathematical models are developed and used to conduct uncertainty analysis for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46% with 95% confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded anuncertainty of 1.46% with 99% confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other, and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study.

Song, Li; Wang, Gang; Brambley, Michael R.

2013-04-28T23:59:59.000Z

357

Renovation and remaining life management techniques for the reliable operation of steam turbine valve casings  

SciTech Connect (OSTI)

Much attention has been focused on the renovation and remaining life management of steam turbine casings. Properly engineered casing repairs, design upgrades, and strategies such as thermal stress monitoring/control, have been successfully employed to keep older steam turbine casings operating reliably until projected plant decommissioning dates. These proven solutions have resulted in a much lower cost alternative to turbine casing replacement. Valve casings are also subject to the rigors of high pressure/temperature operating environments and have a significant replacement cost as well. The same techniques employed to renovate turbine casings can also be successfully applied to valve casings to ensure their reliable operation for the projected plant life. Of particular interest are design upgrades which can be introduced during the renovation. Advances in computer modeling and techniques such as Finite Element analysis have provided engineers with tools not available during the original casing design. This provides an opportunity to not only restore the casings to their original design, but to re-engineer the casings to exceed original design parameters. This paper will cover the engineering analysis of valve casing defects, restoration techniques, and design upgrades. Thermal stress monitoring will be introduced as a technique to manage remaining life. Typical failure modes in various valve casing designs as well as design improvements will be stressed. It will also use case studies to demonstrate the economic and technical advantages of valve and turbine casing renovation.

Rasmussen, D.M.; Otterlee, T.J. [Turbine Consultants, Inc., Milwaukee, WI (United States)

1994-12-31T23:59:59.000Z

358

Apparatus and method for non-invasive diagnosis and control of motor operated valve condition  

DOE Patents [OSTI]

An apparatus compares the torque from an MOV motor with the valve displacement, and from the comparison assesses MOV operating condition. A transducer measures the vibration of the housing of an MOV. The vibrations are due to the motions of the rotating elements within the housing, which motions are directly related to the motion of the valve relative to its seat. Signal processing apparatus analyzes the vibrations to recover the rotations of the rotating elements and thus the motion of the valve plug. Lost motion can also be determined (if a lost motion connection exists) by demodulating the vibration signal and thus taking into account also the lost motion. Simultaneously, the forces applied to the valve are estimated by estimating the torque between the stator and the rotor of the motor. Such torque can be estimated from measuring the input current and voltage alone, using a forgetting factor and a correction for the forgetting factor. A signature derived from relating the torque to the valve position can be used to assess the condition of the MOV, by comparing the signature to signatures for MOVs of known conditions. The vibration analysis components generate signals that relate to the position of elements in the operator. Similarly, the torque estimator estimates the torque output by any type of electric motor, whether or not part of an MOV analysis unit.

Lyon, Richard H. (Belmont, MA); Chai, Jangbom (Seoul, KR); Lang, Jeffrey H. (Sudbury, MA); Hagman, Wayne H. (Belmont, MA); Umans, Stephen D. (Belmont, MA); Saarela, Olli J. (Helsinki, FI)

1997-01-01T23:59:59.000Z

359

Heart valve cardiomyocytes of mouse embryos express the serotonin transporter SERT  

SciTech Connect (OSTI)

Multiple evidence demonstrate a role for serotonin and its transporter SERT in heart valve development and disease. By utilizing a Cre/loxP system driven by SERT gene expression, we recently demonstrated a regionally restricted distribution of SERT-expressing cells in developing mouse heart. In order to characterize the cell types exhibiting SERT expression within the mouse heart valves at early developmental stages, in this study we performed immunohistochemistry for Islet1 (Isl1) and connexin-43 (Cx-43) on heart sections from SERT{sup Cre/+};ROSA26R embryos previously stained with X-gal. We observed the co-localization of LacZ staining with Isl1 labelling in the outflow tract, the right ventricle and the conal region of E11.5 mouse heart. Cx-43 labelled cells co-localized with LacZ stained cells in the forming atrioventricular valves. These results demonstrate the cardiomyocyte phenotype of SERT-expressing cells in heart valves of the developing mouse heart, thus suggesting an active role of SERT in early heart valve development.

Pavone, Luigi Michele [Department of Biological Structures, Functions and Technologies, University of Naples Federico II, Via F. Delpino 1, 80137 Naples (Italy); Department of Biochemistry and Medical Biotechnologies, University of Naples Federico II, Naples (Italy)], E-mail: pavone@dbbm.unina.it; Spina, Anna; Lo Muto, Roberta; Santoro, Dionea [Department of Biological Structures, Functions and Technologies, University of Naples Federico II, Via F. Delpino 1, 80137 Naples (Italy); Department of Biochemistry and Medical Biotechnologies, University of Naples Federico II, Naples (Italy); Mastellone, Vincenzo [Department of Experimental Medicine 'G. Salvatore', University of Magna Graecia, Catanzaro (Italy); Avallone, Luigi [Department of Biological Structures, Functions and Technologies, University of Naples Federico II, Via F. Delpino 1, 80137 Naples (Italy)

2008-12-12T23:59:59.000Z

360

Steady-State Flow-Force Compensation in a Hydraulic Spool Valve  

E-Print Network [OSTI]

A high-speed jet flowing inside of a partially-open hydraulic valve is accompanied by a reaction force, also referred to as flow force. The nature of this force has remained a mystery despite an extensive research effort spanning many decades. The momentum theory on the flow force by Lee and Blackburn (1952) explains the origin of the flow force and offers a design solution to shape the valve spool as a turbine bucket. It provides a model to calculate the compensated flow force as well. This paper shows that the model applies to a different flow case due to incorrect assumptions made. A corrected equation is presented based on a detailed analysis of the static-pressure distribution in the valve cavity as well as on a literature review of pressure loss in diffusers and nozzles. The new equation is based on the compensation taking place upstream of the valve orifice, not downstream as assumed by the momentum theory. The new model can be applied to chamfers or notches on the valve spool without the need to machi...

Lugowski, Jan

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

In this research project I will design and build a demo model of Professor Sun's patented camless valve actuator device. Modern internal combustion engines rely on valves in each  

E-Print Network [OSTI]

valve actuator device. Modern internal combustion engines rely on valves in each cylinder to open, they can be programmed to allow much more efficiency in the combustion cycle at any engine speed, with any the engine and instead replaces it with electronic actuators that can be precisely controlled by the onboard

Minnesota, University of

362

Half-metallic magnetism and the search for better spin valves  

SciTech Connect (OSTI)

We use a previously proposed theory for the temperature dependence of tunneling magnetoresistance to shed light on ongoing efforts to optimize spin valves. First, we show that a mechanism in which spin valve performance at finite temperatures is limited by uncorrelated thermal fluctuations of magnetization orientations on opposite sides of a tunnel junction is in good agreement with recent studies of the temperature-dependent magnetoresistance of high quality tunnel junctions with MgO barriers. Using this insight, we propose a simple formula which captures the advantages for spin-valve optimization of using materials with a high spin polarization of Fermi-level tunneling electrons, and of using materials with high ferromagnetic transition temperatures. We conclude that half-metallic ferromagnets can yield better spin-value performance than current elemental transition metal ferromagnet/MgO systems only if their ferromagnetic transition temperatures exceed ?950?K.

Everschor-Sitte, Karin; Sitte, Matthias; MacDonald, Allan H. [Department of Physics, The University of Texas at Austin, 2515 Speedway, Austin, Texas 78712 (United States)

2014-08-28T23:59:59.000Z

363

Vehicle Technologies Office Merit Review 2014: High Efficiency VCR Engine with Variable Valve Actuation and new Supercharging Technology  

Broader source: Energy.gov [DOE]

Presentation given by Envera LLC at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high efficiency VCR engine...

364

Variable Mass Theories of Gravity  

E-Print Network [OSTI]

Several attempts to construct theories of gravity with variable mass are considered. The theoretical impacts of allowing the rest mass to vary with respect to time or an appropriate curve parameter are examined in the framework of Newtonian and Einsteinian gravity theories. In further steps, scalar-tensor theories are examined with respect to their relation to the variation of the mass and in an ultimate step, an additional coordinate is introduced and its possible relation to the mass is examined, yielding a five dimensional space-time-matter theory.

M. Leclerc

2002-12-03T23:59:59.000Z

365

Characterization of a Micro-Mixing, Pumping, and Valving System Ajay A. Deshmukh, Dorian Liepmann, and Albert P. Pisano  

E-Print Network [OSTI]

Characterization of a Micro-Mixing, Pumping, and Valving System Ajay A. Deshmukh, Dorian Liepmann the performance of a complete pulsatile-flow, continuous micromixing system which utilizes new technology pumps measurements. Keywords: Mixer, Pump, Valve INTRODUCTION A new MEMS pumping and mixing system has been developed

Liepmann, Dorian

366

Spin-dependent thermal and electrical transport in a spin-valve system Zheng-Chuan Wang,1  

E-Print Network [OSTI]

Spin-dependent thermal and electrical transport in a spin-valve system Zheng-Chuan Wang,1 Gang Su,1 governed by thermal processes at high temperature. The so-called spin-valve phenomenon is clearly uncovered, the quantum size effect on the thermal conduc- tance and the Peltier coefficient,2 the diffusive thermopower

Gao, Song

367

Risk assessment of K basin twelve-inch drain valve failure from a postulated seismic initiating event  

SciTech Connect (OSTI)

The Spent Nuclear Fuel (SNF) Project will transfer metallic SNF from the Hanford 105 K-East and 105 K-West Basins to safe interim storage in the Canister Storage Building in the 200 Area. The initial basis for design, fabrication, installation, and operation of the fuel removal systems was that the basin leak rates which could result from a postulated accident condition would not be excessive relative to reasonable recovery operations. However, an additional potential K Basin water leak path is through the K Basin drain valves. Three twelve-inch drain valves are located in the main basin bays along the north wall. The sumps containing the valves are filled with concrete which covers the drain valve body. Visual observations suggest that only the valve's bonnet and stem are exposed above the basin concrete floor. It was recognized, however, that damage of the drain valve bonnet or stem during a seismic initiating event could provide a potential K Basin water leak path. The objectives of this activity are to: (1) evaluate the risk of damaging the three twelve-inch drain valves located along the north wall of the main basin from a seismic initiating event, and (2) determine the associated potential leak rate from a damaged valve.

MORGAN, R.G.

1999-04-06T23:59:59.000Z

368

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

E-Print Network [OSTI]

section, and outlet turbine. A CFD model is created for each section, and then verified. The equations that predict the valve performance has been validated for the inlet rail with nozzles and the outlet turbine, valve design, throttle-less control 1 INTRODUCTION Hydraulic actuation systems have been widely used due

Li, Perry Y.

369

LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility  

SciTech Connect (OSTI)

This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.

Candy, J V

1999-10-31T23:59:59.000Z

370

Spin-transfer switching of orthogonal spin-valve devices at cryogenic temperatures  

SciTech Connect (OSTI)

We present the quasi-static and dynamic switching characteristics of orthogonal spin-transfer devices incorporating an out-of-plane magnetized polarizing layer and an in-plane magnetized spin valve device at cryogenic temperatures. Switching at 12?K between parallel and anti-parallel spin-valve states is investigated for slowly varied current as well as for current pulses with durations as short as 200 ps. We demonstrate 100% switching probability with current pulses 0.6?ns in duration. We also present a switching probability diagram that summarizes device switching operation under a variety of pulse durations, amplitudes, and polarities.

Ye, L., E-mail: ly17@nyu.edu; Gopman, D. B.; Rehm, L.; Backes, D.; Wolf, G.; Kent, A. D. [Department of Physics, New York University, New York, New York 10003 (United States); Ohki, T. [Raytheon BBN Technologies, Cambridge, Massachusetts 02138 (United States); Kirichenko, A. F.; Vernik, I. V.; Mukhanov, O. A. [HYPRES, 175 Clearbrook Road, Elmsford, New York 10523 (United States)

2014-05-07T23:59:59.000Z

371

Fail Save Shut Off Valve for Filtering Systems Employing Candle Filters  

DOE Patents [OSTI]

The invention relates to an apparatus that acts as a fail save shut off valve. More specifically, the invention relates to a fail save shut off valve that allows fluid flow during normal operational conditions, but prevents the flow of fluids in the event of system failure upstream that causes over-pressurization. The present invention is particularly well suited for use in conjunction with hot gas filtering systems, which utilize ceramic candle filters. Used in such a hot gas system the present invention stops the flow of hot gas and prevents any particulate laden gas from entering the clean side of the system.

VanOsdol, John

2006-01-03T23:59:59.000Z

372

In-situ magnetoresistance measurements during patterning of spin valve devices  

E-Print Network [OSTI]

. This dissertation does not exceed the limit of length. Some of the work in this thesis has been published as listed below. Publications Control of the switching properties of magnetic thin films and spin valve devices by patterning, D.Morecroft, C... .W. Leung, N.A. Stelmashenko, J.L. Prieto, D.B. Jardine and M.G. Blamire. IEEE Trans. Mag. 37 Issue: 4 Part: 1 (2001) pp. 2079 2081. In-situ magnetoresistance measurements during patterning of thin films and spin valve devices, D.Morecroft, C...

Morecroft, Deborah

373

Fail save shut off valve for filtering systems employing candle filters  

DOE Patents [OSTI]

The invention relates to an apparatus that acts as a fail save shut off valve. More specifically, the invention relates to a fail save shut off valve that allows fluid flow during normal operational conditions, but prevents the flow of fluids in the event of system failure upstream that causes over-pressurization. The present invention is particularly well suited for use in conjunction with hot gas filtering systems, which utilize ceramic candle filters. Used in such a hot gas system the present invention stops the flow of hot gas and prevents any particulate laden gas from entering the clean side of the system.

VanOsdol, John (Fairmont, WV)

2006-01-03T23:59:59.000Z

374

Sealing off a carbon nanotube with a self-assembled aqueous valve for the storage of hydrogen in GPa pressure  

E-Print Network [OSTI]

The end section of a carbon nanotube, cut by acid treatment, contains hydrophillic oxygen groups. Water molecules can self-assemble around these groups to seal off a carbon nanotube and form an "aqueous valve". Molecular dynamics simulations on single-wall (12,12) and (15,15) tubes with dangling carboxyl groups show that the formation of aqueous valves can be achieved both in the absence of and in the presence of high pressure hydrogen. Furthermore, significant diffusion barriers through aqueous valves are identified. It indicates that such valves could hold hydrogen inside the tube with GPa pressure. Releasing hydrogen is easily achieved by melting the "aqueous valve". Such a design provides a recyclable and non- destructive way to store hydrogen in GPa pressure. Under the storage conditions dictated by sealing off the container in liquid water, the hydrogen density inside the container is higher than that for solid hydrogen, which promises excellent weight storage efficiency.

Chen, H Y; Gong, X G; Liu, Zhi-Feng

2012-01-01T23:59:59.000Z

375

Construction integrity assessment report (ETN-98-0005) S-Farm overground transfer (OGT) system valve pit 241-S-B to valve pit 241-S-D  

SciTech Connect (OSTI)

The S-Farm overground transfer (OGT) line will bypass the existing line(s), between valve pits 241-S-B and 241-S-D that no longer meet system requirements. The new OGT line will provide a waste transfer pipeline between these valve pits in support of saltwell pumping activities. The length of the OGT line is approximately 180 ft from pit to pit. The primary pipe is nominal 1-in. diameter stainless steel (SST) braided Ethylene-propylene Diene Monomer (EPDM) hose. The encasement pipe is a nominal 3-in., flanged, SST pipe made up of several different length pipe spool pieces (drawing H-2-829564, sh. 1 and sh. 2). The OGT line slopes from valve pit 241-S-B toward valve pit 241-S-D. At each end, the primary and encasement pipe connect to a pit entry spool piece. The pit entry spool pieces are constructed of prefabricated SST materials. These spool pieces allow for the separation of the primary and encasement pipelines after the pipes have entered the valve pits (drawing H-2-818280, sh. 2). The pit entry spool pieces also allow for leak detection of the encasement pipe at each end (drawing H-2-829564, sh. 2). The OGT encasement pipeline is supported above ground by adjustable height unistrut brackets and precast concrete bases (drawing H-2-829654, sh. 1). The pipeline is heat-traced and insulated. The heat tracing and insulation supply and retain latent heat that prevents waste solidification during transfers and provides freeze protection. The total length of the pipeline is above ground, thereby negating the need for cathodic corrosion protection. This Construction Integrity Assessment Report (CIAR) is prepared by Fluor Daniel Northwest for Numatec Hanford Corporation/Lockheed Martin Hanford Corporation, the operations contractor, and the U. S. Department of Energy, the system owner. The CIAR is intended to verify that construction was performed in accordance with the provisions of Washington Administrative Code, WAC-173-303-640 (3) (c), (e), (f) and (h).

HICKS, D.F.

1999-08-12T23:59:59.000Z

376

Extremum Seeking Control for Soft Landing of an Electromechanical Valve Actuator  

E-Print Network [OSTI]

SPACE Controller Laser Vibrometer Eddy current Sensor Sensor Target Spring Upper Coil Lower Coil Armature Valve by inducing current in a coil of wire to give rise to a magnetic force. This force is then used to affect sets of springs and elec- tromagnets. The pre-load of each spring is set such that they are both always

Stefanopoulou, Anna

377

Evidence for spin selectivity of triplet pairs in superconducting spin valves  

E-Print Network [OSTI]

in spintronics to control the flow of electrons by ferromagnets in a ferromagnet (F1)/normal metal (N)/ferromagnet (F2) spin valve, where F1 acts as the polarizer and F2 the analyser. The feasibility of superconducting spintronics depends on the spin sensitivity...

Banerjee, N.; Smiet, C. B.; Smits, R. G. J.; Ozaeta, A.; Bergeret, F. S.; Blamire, M. G.; Robinson, J. W. A.

2014-01-09T23:59:59.000Z

378

Strength and Fatigue of NT551 Silicon Nitride and NT551 Diesel Exhaust Valves  

SciTech Connect (OSTI)

The content of this report is excerpted from Mark Andrew's Ph.D. Thesis (Andrews, 1999), which was funded by a DOEYOTT High Temperature Materials Laboratory Graduate Fellowship. It involves the characterization of NT551 and valves fabricated with it. Greater detail of the described issues may be found in that reference or through communications with Andrew Wereszczak.

Andrews, M.J.; Wereszczak, A.A.; Kirkland, T.P.; Breder, K.

2000-02-01T23:59:59.000Z

379

Cost effective combined axial fan and throttling valve control of ventilation rate  

E-Print Network [OSTI]

, the throttling valve is employed to restrict airflow at the outlet, so generating a higher static pressure differ levels of moisture, heat and internal gases are generated. For this reason, the lack of effective-based controller and a previously developed scheduled PIP design, yielding a re- duction in power consumption

Sengun, Mehmet Haluk

380

Inhibition of aortic wall calcification in bioprosthetic heart valves by ethanol pretreatment: Biochemical and  

E-Print Network [OSTI]

Inhibition of aortic wall calcification in bioprosthetic heart valves by ethanol pretreatment 16 September 1997; 20 February 1998 Abstract: The effectiveness of ethanol pretreatment on pre was previously demonstrated, and the mechanism of action of ethanol was attributed in part to both lipid removal

Zand, Robert

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Establishment of the mathematical model for diagnosing the engine valve faults by genetic  

E-Print Network [OSTI]

in a six- cylinders/four-stroke cycle diesel engine, i.e. normal condition, valve-tappet clearance and gas for diagnosing the faults occurring in rotor-bearing system, but current computer programs cannot easily distinguish the orbit shapes automatically. Likewise, when diagnosing the faults in a rolling-element bearing

Fernandez, Thomas

382

Thermocapillary valve for droplet production and sorting Charles N. Baroud,1,  

E-Print Network [OSTI]

for use as microfluidic reactors, if active control of their formation and transport can be achieved. We as a microfluidic valve for two-phase flows. A theoretical model is developed to explain the forces acting on a drop in complex droplet microfluidic systems. PACS numbers: 47.61.-k, 47.55.dm Microfluidic droplets have been

Boyer, Edmond

383

An Active Motion Compensation Instrument for Beating Heart Mitral Valve Surgery  

E-Print Network [OSTI]

An Active Motion Compensation Instrument for Beating Heart Mitral Valve Surgery Daniel T. Kettler) is described. The resulting instrument was tested in user trials under a series of positional error bandwidth, creating a wrist that can operate in the restricted workspace within the heart, and ensuring

384

Analysis of system performance losses due to the reversing valve for a heat pump using R-410a  

SciTech Connect (OSTI)

A traditional reversing valve enables a heat pump to operate in the heating mode or cooling mode by switching the refrigerant flow path through the indoor and outdoor coils, thereby changing the functions of the two heat exchangers. However, the presence of a reversing valve causes additional pressure drops and undesired heat exchange. The objective of this research was to measure the overall effects of a reversing valve on a 3-ton heat pump system using R-401a and make comparisons to the same valve's performance with R-22 as the refrigerant. The experiments included tests of under- and over-sized valves at the same test conditions. Also, the effects of pressure drops and of heat transfer combined with mass leakage on system and compressor performance were analyzed. It was found that the use of a larger (oversized) reversing valve to reduce pressure drops provided only limited performance gains. Also, changing refrigerant from R-22 to R-410a resulted in an increase in mass leakage but did not significantly change the effect that the reversing valve had on the system COP.

Fang, W.; Nutter, D.W.

1999-07-01T23:59:59.000Z

385

Unit commitment with valve-point loading effect  

E-Print Network [OSTI]

Apr 18, 2014 ... applied to a related problem: that of optimizing short-term hydro scheduling. ..... bounds is small enough (or the allowed CPU time is exceeded).

2014-04-18T23:59:59.000Z

386

Understanding Biomass Feedstock Variability  

SciTech Connect (OSTI)

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

2013-01-01T23:59:59.000Z

387

Understanding Biomass Feedstock Variability  

SciTech Connect (OSTI)

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per-ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that, due to inherent species variabilities, production conditions and differing harvest, collection and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; Garold L. Gresham; William A. Smith; Tyler L. Westover

2013-01-01T23:59:59.000Z

388

Detection of ``single-leg separated`` heart valves using statistical pattern recognition with the nearest neighbor classifier  

SciTech Connect (OSTI)

The goal of this work was to detect ``single-leg separated`` Bjoerk-Shiley Convexo-Concave heart valves which had been implanted in sheep. A ``single-leg separated`` heart valve contains a fracture in the outlet strut resulting in an increased risk of mechanical failure. The approach presented in this report detects such fractures by applying statistical pattern recognition with the nearest neighbor classifier to the acoustic signatures of the valve opening. This approach is discussed and results of applying it to real data are given.

Buhl, M.R.; Clark, G.A.; Candy, J.V.; Thomas, G.H.

1993-07-16T23:59:59.000Z

389

Detection of ``single-leg separated`` heart valves using statistical pattern recognition with the nearest neighbor classifier. Revision 1  

SciTech Connect (OSTI)

The goal of this work was to detect ``single-leg separated`` Bjoerk-Shiley Convexo-Concave heart valves which had been implanted in sheep. A ``single-leg separated`` heart valve contains a fracture in the outlet strut resulting in an increased risk of mechanical failure. The approach presented in this report detects such fractures by applying statistical pattern recognition with the nearest neighbor classifier to the acoustic signatures of the valve opening. This approach is discussed and results of applying it to real data are given.

Buhl, M.R.; Clark, G.A.; Candy, J.V.; Thomas, G.H.

1993-12-01T23:59:59.000Z

390

First-passage-time problems in time-aware networks  

E-Print Network [OSTI]

First passage time or the first time that a stochastic process crosses a boundary is a random variable whose probability distribution is sought in engineering, statistics, finance, and other disciplines. The probability ...

Suwansantisuk, Watcharapan, 1978-

2012-01-01T23:59:59.000Z

391

In-Cylinder Reaction Chemistry and Kinetics During Negative Valve Overlap Fuel Injection Under Low-Oxygen Conditions  

SciTech Connect (OSTI)

Fuel injection into the negative valve overlap (NVO) period is a common method for controlling combustion phasing in homogeneous charge compression ignition (HCCI) as well as other forms of advanced combustion. During this event, at least a portion of the fuel hydrocarbons can be converted to products containing significant levels of H2 and CO, as well as other short chain hydrocarbons by means of thermal cracking, water-gas shift, and partial oxidation reactions, depending on the availability of oxygen and the time-temperature-pressure history. The resulting products alter the autoignition properties of the combined fuel mixture for HCCI. Fuel-rich chemistry in a partial oxidation environment is also relevant to other high efficiency engine concepts (e.g., the dedicated EGR (D-EGR) concept from SWRI). In this study, we used a unique 6-stroke engine cycle to experimentally investigate the chemistry of a range of fuels injected during NVO under low oxygen conditions. Fuels investigated included iso-octane, iso-butanol, ethanol, and methanol. Products from NVO chemistry were highly dependent on fuel type and injection timing, with iso-octane producing less than 1.5% hydrogen and methanol producing more than 8%. We compare the experimental trends with CHEMKIN (single zone, 0-D model) predictions using multiple kinetic mechanisms available in the current literature. Our primary conclusion is that the kinetic mechanisms investigated are unable to accurately predict the magnitude and trends of major species we observed.

Kalaskar, Vickey B [ORNL] [ORNL; Szybist, James P [ORNL] [ORNL; Splitter, Derek A [ORNL] [ORNL; Pihl, Josh A [ORNL] [ORNL; Gao, Zhiming [ORNL] [ORNL; Daw, C Stuart [ORNL] [ORNL

2013-01-01T23:59:59.000Z

392

Replace Pressure-Reducing Valves with Backpressure Turbogenerators (International Fact Sheet), Energy Tips-Steam, Steam Tip Sheet #20c  

SciTech Connect (OSTI)

This English/Chinese ITP steam tip sheet on replacing pressure-reducing valves provides how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.

Not Available

2010-10-01T23:59:59.000Z

393

Variable Frequency Pump Drives  

E-Print Network [OSTI]

-frequency electric motor drive. What is happenin9 with variable frequency driven pun,ps is a classical illustration that evolution in technical products takes place not only because of changes in the processes served by these products, or because of innovations...-pole 3550 rpm squirrel caqe induction motor became available in the early 1930s that high pressure pumps operating at that speed could be buil t. And now, in the 1980s, the development of the solid-state, variable frequency electric motor drive...

Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

394

Replace Pressure-Reducing Valves with Backpressure Turbogenerators: Office of Industrial Technologies (OIT) Steam Tip Fact Sheet No. 20  

SciTech Connect (OSTI)

Many industrial facilities produce steam at a higher pressure than is demanded by process requirements. Steam passes through pressure-reducing valves (PRVs, also known as letdown valves) at various locations in the steam distribution system to let down or reduce its pressure. A non-condensing or backpressure steam turbine can perform the same pressure-reducing function as a PRV, while converting steam energy into electrical energy.

Not Available

2002-01-01T23:59:59.000Z

395

Bimodal switching field distributions in all-perpendicular spin-valve nanopillars  

SciTech Connect (OSTI)

Switching field measurements of the free layer element of 75?nm diameter spin-valve nanopillars reveal a bimodal distribution of switching fields at low temperatures (below 100?K). This result is inconsistent with a model of thermal activation over a single perpendicular anisotropy barrier. The correlation between antiparallel to parallel and parallel to antiparallel switching fields increases to nearly 50% at low temperatures. This reflects random fluctuation of the shift of the free layer hysteresis loop between two different magnitudes, which may originate from changes in the dipole field from the polarizing layer. The magnitude of the loop shift changes by 25% and is correlated to transitions of the spin-valve into an antiparallel configuration.

Gopman, D. B., E-mail: daniel.gopman@physics.nyu.edu; Kent, A. D. [Department of Physics, New York University, New York, New York 10003 (United States); Bedau, D.; Katine, J. A. [HGST San Jose Research Center, San Jose, California 95135 (United States); Mangin, S. [Institut Jean Lamour, UMR CNRS 7198 Universit de Lorraine, Nancy (France); Fullerton, E. E. [CMRR, University of California at San Diego, La Jolla, California 92093 (United States)

2014-05-07T23:59:59.000Z

396

Testing of one-inch UF{sub 6} cylinder valves under simulated fire conditions  

SciTech Connect (OSTI)

Accurate computational models which predict the behavior of UF{sub 6} cylinders exposed to fires are required to validate existing firefighting and emergency response procedures. Since the cylinder valve is a factor in the containment provided by the UF{sub 6} cylinder, its behavior under fire conditions has been a necessary assumption in the development of such models. Consequently, test data is needed to substantiate these assumptions. Several studies cited in this document provide data related to the behavior of a 1-inch UF{sub 6} cylinder valve in fire situations. To acquire additional data, a series of tests were conducted at the Paducah Gaseous Diffusion Plant (PGDP) under a unique set of test conditions. This document describes this testing and the resulting data.

Elliott, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31T23:59:59.000Z

397

Giant amplification of tunnel magnetoresistance in a molecular junction: Molecular spin-valve transistor  

SciTech Connect (OSTI)

Amplification of tunnel magnetoresistance by gate field in a molecular junction is the most important requirement for the development of a molecular spin valve transistor. Herein, we predict a giant amplification of tunnel magnetoresistance in a single molecular spin valve junction, which consists of Ru-bis-terpyridine molecule as a spacer between two ferromagnetic nickel contacts. Based on the first-principles quantum transport approach, we show that a modest change in the gate field that is experimentally accessible can lead to a substantial amplification (320%) of tunnel magnetoresistance. The origin of such large amplification is attributed to the spin dependent modification of orbitals at the molecule-lead interface and the resultant Stark effect induced shift in channel position with respect to the Fermi energy.

Dhungana, Kamal B.; Pati, Ranjit, E-mail: patir@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

2014-04-21T23:59:59.000Z

398

Solids throttling valves for coal conversion and utilization development. Final report  

SciTech Connect (OSTI)

A complete test system to test, evaluate, and develop control valves for slurry letdown service in coal liquefaction plants is needed. The site identified for the test system was the SRC II Pilot Plant located at Ft. Lewis, Washington. The US Department of Energy, Morgantown Energy Technology Center, requested a test system design that would enable testing of various configuration letdown valves that would be compatible with the existing facility and have minimum impact on Pilot Plant operations. Drawings and specifications for such a test system were prepared, coordinated with Ft. Lewis personnel, revised to reflect Ft. Lewis operating personnel comments, and approved for use by the Morgantown Energy Technology Center. These drawings and specifications will enable the test system to be built, installed, and integrated with the existing facility by a general contractor.

Sine, G.C.

1980-11-01T23:59:59.000Z

399

Simulation of relaxation times and energy spectra of the CdTe/Hg{sub 1-x}Cd{sub x}Te/CdTe quantum well for variable valence band offset, well width, and composition x  

SciTech Connect (OSTI)

The dependences of relaxation times and energy spectrum of the CdTe/Hg{sub 1-x}Cd{sub x}Te/CdTe quantum well (QW) on its parameters were simulated in the cadmium molar fraction range 0 < x < 0.16. It was found that the x increase from 0 to 0.16 changes electron wave function localization in the QW. A criterion for determining the number of interface levels of localized electrons depending on QW parameters was obtained. The effect of a sharp (by two orders of magnitude) increase in the relaxation time of localized electrons was detected at small QW widths and x close to 0.16.

Melezhik, E. O., E-mail: emelezhik@gmail.com; Gumenjuk-Sichevska, J. V.; Sizov, F. F. [National Academy of Sciences, Lashkariev Institute of Semiconductor Physics (Ukraine)

2010-10-15T23:59:59.000Z

400

Design, testing and use of a lockable flapper float valve for the Ocean Drilling Program  

E-Print Network [OSTI]

are used. The two most common and readily applicable techniques are application of hydraulic pressure and pulling with a wireline attached to a "shifting tool". These techniques and the associated tools were already employed in several other downhole..., but not into, the bottom of the pipe. Ordinarily this standard device works adequately. However, when electric logging tools or other wellbore measuring instruments are lowered on a wireline and ajlowed to pass out the end of the pipe the float valve...

Huey, David Philip

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Project W-314 Specific Test and Evaluation Plan 241-AN-A Valve Pit  

SciTech Connect (OSTI)

The purpose of this Specific Test and Evaluation Plan (STEP) is to provide a detailed written plan for the systematic testing of modifications made to the 241-AN-A Valve Pit by the W-314 Project. The STEP develops the outline for test procedures that verify the system's performance to the established Project design criteria. The STEP is a lower tier document based on the W-314 Test and Evaluation Plan (TEP).

HAMMERS, J.S.

1999-08-25T23:59:59.000Z

402

Mechanisms of bioprosthetic heart valve failure: Fatigue causes collagen denaturation and glycosaminoglycan loss  

E-Print Network [OSTI]

caused progressive damage to the molecular structure of type I collagen as assessed by Fourier transform aortic valve cusps were 65.2 ± 8.66 g uronic acid/10 mg of dry weight for control and 7.91 ± 1.1 g uronic acid/10 mg of dry weight for 10­300 million cycled cusps. Together, these molecular changes contribute

Zand, Robert

403

Operational Experience and Consolidations for the Current Lead Control Valves of the Large Hadron Collider  

E-Print Network [OSTI]

The Large Hadron Collider superconducting magnets are powered by more than 1400 gas cooled current leads ranging from 120 A to 13000 A. The gas flow required by the leads is controlled by solenoid proportional valves with dimensions from DN 1.8 mm to DN 10 mm. During the first months of operation, signs of premature wear were found in the active parts of the valves. This created major problems for the functioning of the current leads threatening the availability of the LHC. Following the detection of the problems, a series of measures were implemented to keep the LHC running, to launch a development program to solve the premature wear problem and to prepare for a global consolidation of the gas flow control system. This article describes first the difficulties encountered and the measures taken to ensure a continuous operation of the LHC during the first year of operation. The development of new friction free valves is then presented along with the consolidation program and the test equipment developed to val...

Perin, A; Pirotte, O; Krieger, B; Widmer, A

2012-01-01T23:59:59.000Z

404

The VISTA Variables in the Via Lactea survey: A first glance on stellar variability  

E-Print Network [OSTI]

VISTA Variables in the Via Lactea (VVV) is an ESO public near-infrared variability survey of the Galactic bulge and an adjacent area of the southern mid-plane. It will produce a deep atlas in the ZYJHKs filters, and a Ks-band time-series database of ~10^9 point sources, among which >~10^6 are expected to be variable. One of VVV's immediate scientific goals is to provide accurate light curves of primary distance indicators, such as RR Lyrae stars, and utilize these data to produce a 3-D map of the surveyed area and, ultimately, trace the structure of the inner Galaxy. We give, based on the first ~1.5 years of the 5-yr-long survey, an early assessment on the basic properties and the overall quality of the VVV photometric time-series, and use these data to put an estimate of the fraction of variable stellar sources.

Dekany, I; Minniti, D

2011-01-01T23:59:59.000Z

405

Results of the radiological survey at the former Chapman Valve Manufacturing Company, Indian Orchard, Massachusetts (CIO001)  

SciTech Connect (OSTI)

Radiological survey was conducted at Building 23 (Department No. 40) at the former Chapman Valve Manufacturing Company, Indian Orchard, Massachusetts. The survey was performed in August 1991. The purpose of the survey was to determine whether the property was contaminated with radioactive residues, principally {sup 238}U, as a result of work done for the Atomic Energy Commission (AEC) during the 1940s. The survey included a gamma scan, a beta-gamma scan, and measurement of alpha activity; measurement of direct and removable alpha and beta-gamma levels; and the collection of soil, dust, debris, and smear samples for radionuclide analyses. Survey emphasis was on interior floors, walls, and overhead beams. Radionuclide analysis of soil, dust, and debris, and analysis of smear samples indicate that residual {sup 238}U attributable to former AEC-supported operations is present at this site. Elevated levels of radioactivity were particularly evident on the floors and walls in the western part of the central area of the building (grid blocks Al through A6). Concentrations of {sup 238}U in dust samples collected from overhead beams exceeded DOE guidelines in grid blocks Al through A14 and remained elevated in grid blocks A15 through A19. Dust on a movable overhead crane in grid block A23 was well above the guideline, probably because the crane had at some time been located further west. Some contamination was evident in grid blocks B1 through B5, but clutter and debris in this area prevented a thorough survey.

Foley, R.D.; Uziel, M.S.

1992-07-01T23:59:59.000Z

406

Variable Crop Share Leases.  

E-Print Network [OSTI]

)OC lAL45.7 173 1. 1224 Texas Agricultural Extension Service The Texas A&M University System Daniel C. Pfannstiel,Director colleg e Station, Texas / f , ' '~ :';,; ,,: ''': ~ " k , -~. _Variable _Crop Share _Leases ... Marvin... Sartin and Ray Sammons* Renting or leasing farmland is part of many modern farming operations and increases average farm size in U. S. agriculture. Economies of size are vitally import ant to farm operations as they strive to cope with the continuous...

Sartin, Marvin; Sammons, Ray

1980-01-01T23:59:59.000Z

407

Variable depth core sampler  

DOE Patents [OSTI]

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Bourgeois, P.M.; Reger, R.J.

1996-02-20T23:59:59.000Z

408

Low Temperature Combustion and Diesel Emission Reduction Research  

Broader source: Energy.gov (indexed) [DOE]

Compression ratio control Enablers: Advanced controls Variable Valve Timing Two-stage turbo-charging CoolingEGR Two stage combustion Fuel CN reduction Vaporization too slow...

409

Estimation and Control of Diesel Engine Processes Utilizing Variable...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

diesel engine with cooled EGR and flexible intake valve actuation developed to capture dynamic effects of gas exchange actuators deer12kocher.pdf More Documents &...

410

Measuring spatial variability in soil characteristics  

DOE Patents [OSTI]

The present invention provides systems and methods for measuring a load force associated with pulling a farm implement through soil that is used to generate a spatially variable map that represents the spatial variability of the physical characteristics of the soil. An instrumented hitch pin configured to measure a load force is provided that measures the load force generated by a farm implement when the farm implement is connected with a tractor and pulled through or across soil. Each time a load force is measured, a global positioning system identifies the location of the measurement. This data is stored and analyzed to generate a spatially variable map of the soil. This map is representative of the physical characteristics of the soil, which are inferred from the magnitude of the load force.

Hoskinson, Reed L. (Rigby, ID); Svoboda, John M. (Idaho Falls, ID); Sawyer, J. Wayne (Hampton, VA); Hess, John R. (Ashton, ID); Hess, J. Richard (Idaho Falls, ID)

2002-01-01T23:59:59.000Z

411

Light absorption cell combining variable path and length pump  

DOE Patents [OSTI]

A device for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid therebetween and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data.

Prather, William S. (2419 Dickey Rd., Augusta, GA 30906)

1993-01-01T23:59:59.000Z

412

Light absorption cell combining variable path and length pump  

DOE Patents [OSTI]

A device is described for use in making spectrophotometric measurements of fluid samples. In particular, the device is a measurement cell containing a movable and a fixed lens with a sample of the fluid there between and through which light shines. The cell is connected to a source of light and a spectrophotometer via optic fibers. Movement of the lens varies the path length and also pumps the fluid into and out of the cell. Unidirectional inlet and exit valves cooperate with the movable lens to assure a one-way flow of fluid through the cell. A linear stepper motor controls the movement of the lens and cycles it from a first position closer to the fixed lens and a second position farther from the fixed lens, preferably at least 10 times per minute for a nearly continuous stream of absorption spectrum data. 2 figures.

Prather, W.S.

1993-12-07T23:59:59.000Z

413

Solar activity and earth rotation variability R. Abarca del Rioa,  

E-Print Network [OSTI]

to secular times scales, meteorological and climatic data are correlated with solar variability (see reviews changes in solar output could be amplified in the Earth's atmosphere. In fact, at wavelengths not visibleSolar activity and earth rotation variability R. Abarca del Rioa, *, D. Gambisb , D. Salsteinc , P

Dai, Aiguo

414

PHP: Constructs and Variables Introduction  

E-Print Network [OSTI]

PHP: Constructs and Variables Introduction This document describes: 1. the syntax and types of variables, 2. PHP control structures (i.e., conditionals and loops), 3. mixed-mode processing, 4. how to use one script from within another, 5. how to define and use functions, 6. global variables in PHP, 7

Vander Zanden, Brad

415

Imaging of lateral spin valves with soft x-ray microscopy  

SciTech Connect (OSTI)

We investigated Co/Cu lateral spin valves by means of high-resolution transmission soft x-ray microscopy with magnetic contrast that utilizes x-ray magnetic circular dichroism (XMCD). No magnetic XMCD contrast was observed at the Cu L{sub 3} absorption edge, which should directly image the spin accumulation in Cu. Although electrical transport measurements in a non-local geometry clearly detected the spin accumulation in Cu, which remained unchanged during illumination with circular polarized x-rays at the Co and Cu L{sub 3} absorption edges.

Mosendz, O.; Mihajlovic, G.; Pearson, J. E.; Fischer, P.; Im, M.-Y.; Bader, S. D.; Hoffmann, A.

2009-05-01T23:59:59.000Z

416

Imaging of lateral spin valves with soft x-ray microscopy.  

SciTech Connect (OSTI)

We investigated Co/Cu lateral spin valves by means of high-resolution transmission soft x-ray microscopy with magnetic contrast that utilizes x-ray magnetic circular dichroism (XMCD). No magnetic XMCD contrast was observed at the Cu L{sub 3} absorption edge, which should directly image the spin accumulation in Cu, although electrical transport measurements in a nonlocal geometry clearly detected the spin accumulation in Cu, which remained unchanged during illumination with circular polarized x rays at the Co and Cu L{sub 3} absorption edges.

Mosendz, O.; Mihajlovic, G.; Pearson, J. E.; Fischer, P.; Im, M.-Y.; Bader, S. D.; Hoffmann, A.; LBNL

2009-01-01T23:59:59.000Z

417

Motor-Operated Valve Importance Categorization Study Using Level 1 Internal Event PSA  

SciTech Connect (OSTI)

Recently GL 89-10 static and dynamic Motor-Operated Valve (MOV) tests are being performed in Korean nuclear power plants to ensure MOV operability in design basis condition. And GL 96-05 MOV periodic verification testing will be followed after GL 89-10 testing. MOV risk importance categorization will be incorporated in Korean MOV periodic testing program for effective MOV test. In this study, MOVs were preliminarily categorized based on risk importance measures FV and RAW using level 1 internal event PSA. Configuration effect and importance uncertainty effect to risk importance of MOVs were also investigated. (authors)

Yong Suk Lee; Chang Hyun Chung [Seoul National University (Korea, Republic of); Key Yong Sung [Korea Institute of Nuclear Safety - KINS, 19 Kusong-dong, Yousong-gu, Teajon (Korea, Republic of)

2002-07-01T23:59:59.000Z

418

Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source  

SciTech Connect (OSTI)

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a soft photoionization source for gas-phase mass spectrometry.

Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)] [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)

2013-12-15T23:59:59.000Z

419

Cyclic Variability During the Transition Between Spark-ignited Combustion and HCCI  

SciTech Connect (OSTI)

Experimental observations of cyclic variability are described for the transition between conventional spark-ignited (SI) propagating-flame combustion and homogeneous charge compression ignition (HCCI) combustion in a single-cylinder, stoichiometrically fueled, gasoline engine. The engine under study is equipped with a fully variable valve actuation (VVA) system which was used to control the levels of internal exhaust gas recirculation (EGR) to achieve the transition from conventional SI to HCCI. Engine operation in both SI and HCCI modes was observed to be very stable with only minor, stochastic cyclic variability. However, during transitions between these modes, operation was observed to be highly unstable with high levels of cyclic variability and occasionally the engine could not sustain combustion. Analysis of the observed cyclic variability suggests that the transition between SI and HCCI can be described as a sequence of bifurcations in a low-dimensional dynamic map. The deterministic nature of the instabilities observed during the transition suggest that it is possible to make accurate, short-term predictions of combustion performance allowing for the possibility of developing on-line diagnostics and proactive control algorithms for expanding stable HCCI operation and improving transitions between conventional combustion modes and HCCI.

Edwards, Kevin Dean [ORNL; Daw, C Stuart [ORNL; Wagner, Robert M [ORNL; Green Jr, Johney Boyd [ORNL

2006-01-01T23:59:59.000Z

420

488 Brazilian Journal of Physics, vol. 36, no. 2A, June, 2006 Spin Valve Effect and Hall Resistance in a Wide Parabolic Well  

E-Print Network [OSTI]

488 Brazilian Journal of Physics, vol. 36, no. 2A, June, 2006 Spin Valve Effect and Hall Resistance: Spin valve; Hall resistance; AlcGa1-cAs parabolic wells I. INTRODUCTION The Hall effect is very known by the formula Rxy = R0B+RSM, where B is ap- plied magnetic field, R0 is the ordinary Hall coefficient, and RS

Gusev, Guennady

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Stochastic Estimation of Multi-Variable Human Ankle Mechanical Impedance  

E-Print Network [OSTI]

This article presents preliminary stochastic estimates of the multi-variable human ankle mechanical impedance. We employed Anklebot, a rehabilitation robot for the ankle, to provide torque perturbations. Time histories of ...

Rastgaar Aagaah, Mohammad

422

A study to determine the most effective actuation valve and water distribution head combination for emergency showers  

E-Print Network [OSTI]

for corrosion and wear. Pressure test to determine strength. (5) Remove shower head and dismantle. Clean scale and rust, from the head inlet and from the slots or orifices in the baffle plate. (6) Reassemble. (7) Open OSBY valve and replace seal..., and orifice sprinkler water distribution heads to determine which valve/head combination produced the greatest flow rate at varying static water pressures. Flow rates were measured at static pressures of 20, 30. 40, 50, and 60 pounds per square inch gauge...

Presswood, James Columbus

1977-01-01T23:59:59.000Z

423

Intrinsic Time Quantum Geometrodynamics  

E-Print Network [OSTI]

Quantum Geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together with its ground state and primordial quantum fluctuations. Cotton-York potential dominates at early times when the universe was small; the ground state naturally resolves Penrose's Weyl Curvature Hypothesis, and thermodynamic and gravitational `arrows of time' point in the same direction. Ricci scalar potential corresponding to Einstein's General Relativity emerges as a zero-point energy contribution. A new set of fundamental commutation relations without Planck's constant emerges from the unification of Gravitation and Quantum Mechanics.

Eyo Eyo Ita III; Chopin Soo; Hoi-Lai Yu

2015-02-06T23:59:59.000Z

424

Intrinsic Time Quantum Geometrodynamics  

E-Print Network [OSTI]

Quantum Geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together with its ground state and primordial quantum fluctuations. Cotton-York potential dominates at early times when the universe was small; the ground state naturally resolves Penrose's Weyl Curvature Hypothesis, and thermodynamic and gravitational `arrows of time' point in the same direction. Ricci scalar potential corresponding to Einstein's General Relativity emerges as a zero-point energy contribution. A new set of fundamental canonical commutation relations without Planck's constant emerges from the unification of Gravitation and Quantum Mechanics.

Eyo Eyo Ita III; Chopin Soo; Hoi-Lai Yu

2015-01-26T23:59:59.000Z

425

Conductance valve and pressure-to-conductance transducer method and apparatus  

DOE Patents [OSTI]

A device for interrupting or throttling undesired ionic transport through a fluid network is disclosed. The device acts as a fluid valve by reversibly generating a fixed "bubble" in the conducting solvent solution carried by the network. The device comprises a porous hydrophobic structure filling a portion of a connecting channel within the network and optionally incorporates flow restrictor elements at either end of the porous structure that function as pressure isolation barriers, and a fluid reservoir connected to the region of the channel containing the porous structure. Also included is a pressure pump connected to the fluid reservoir. The device operates by causing the pump to vary the hydraulic pressure to a quantity of solvent solution held within the reservoir and porous structure. At high pressures, most or all of the pores of the structure are filled with conducting liquid so the ionic conductance is high. At lower pressures, only a fraction of the pores are filled with liquid, so ionic conductivity is lower. Below a threshold pressure, the porous structure contains only vapor, so there is no liquid conduction path. The device therefore effectively throttles ionic transport through the porous structure and acts as a "conductance valve" or "pressure-to-conductance" transducer within the network.

Schoeniger, Joseph S.; Cummings, Eric B.; Brennan, James S.

2005-01-18T23:59:59.000Z

426

A nonintrusive method for measuring the operating temperature of a solenoid-operated valve  

SciTech Connect (OSTI)

Experimental data are presented to show that the in-service operating temperature of a solenoid-operated valve (SOV) can be interred simply and nondisruptively by using the copper winding of the solenoid coil as a self-indicating, permanently available resistance thermometer. The principal merits of this approach include (a) there is no need for an add-on temperature sensor, (b) the true temperature of a critical --- and likely the hottest --- part of the SOV (namely, the electrical coil) is measured directly, (c) temperature readout can be provided at any location at which the SOV electrical lead wires are accessible (even though remote from the valve), (d) the SOV need not be disturbed (whether normally energized or deenergized) to measure its temperature in situ, and (e) the method is applicable to all types of SOVs, large and small, ac- and dc-powered. Laboratory tests comparing temperatures measured both by coil resistance and by a conventional thermometer placed in contact with the external surface of the potted solenoid coil indicate that temperature within the coil may be on the order of 40{degree}C higher than that measured externally, a fact that is important to life-expectancy calculations made on the basis of Arrhenius theory. Field practicality is illustrated with temperature measurements made using this method on a SOV controlling the flow of refrigerant in a large chilled-water air-conditioning system. 5 refs., 7 figs.

Kryter, R.C.

1990-01-01T23:59:59.000Z

427

Thermodynamics in variable speed of light theories  

E-Print Network [OSTI]

The perfect fluid in the context of a covariant variable speed of light theory proposed by J. Magueijo is studied. On the one hand the modified first law of thermodynamics together with a recipe to obtain equations of state are obtained. On the other hand the Newtonian limit is performed to obtain the nonrelativistic hydrostatic equilibrium equation for the theory. The results obtained are used to determine the time variation of the radius of Mercury induced by the variability of the speed of light ($c$), and the scalar contribution to the luminosity of white dwarfs. Using a bound for the change of that radius and combining it with an upper limit for the variation of the fine structure constant, a bound on the time variation of $c$ is set. An independent bound is obtained from luminosity estimates for Stein 2015B.

Juan Racker; Pablo Sisterna; Hector Vucetich

2009-11-30T23:59:59.000Z

428

Thermodynamics in variable speed of light theories  

SciTech Connect (OSTI)

The perfect fluid in the context of a covariant variable speed of light theory proposed by J. Magueijo is studied. On the one hand the modified first law of thermodynamics together with a recipe to obtain equations of state are obtained. On the other hand the Newtonian limit is performed to obtain the nonrelativistic hydrostatic equilibrium equation for the theory. The results obtained are used to determine the time variation of the radius of Mercury induced by the variability of the speed of light (c), and the scalar contribution to the luminosity of white dwarfs. Using a bound for the change of that radius and combining it with an upper limit for the variation of the fine structure constant, a bound on the time variation of c is set. An independent bound is obtained from luminosity estimates for Stein 2015B.

Racker, Juan [CONICET, Centro Atomico Bariloche, Avenida Bustillo 9500 (8400), San Carlos De Bariloche (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900), La Plata (Argentina); Sisterna, Pablo [Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600), Mar del Plata (Argentina); Vucetich, Hector [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900), La Plata (Argentina)

2009-10-15T23:59:59.000Z

429

VARIABLE FIRING RATE OIL BURNER USING PULSE FUEL FLOW CONTROL.  

SciTech Connect (OSTI)

The residential oil burner market is currently dominated by the pressure-atomized retention head burner, which has an excellent reputation for reliability and efficiency. In this burner, oil is delivered to a fuel nozzle at pressures from 100 to 150 psi. In addition, to atomizing the fuel, the small, carefully controlled size of the nozzle exit orifice serves to control the burner firing rate. Burners of this type are currently available at firing rates of more than 0.5 gallons-per-hour (70,000 Btu/hr). Nozzles have been made for lower firing rates, but experience has shown that such nozzles suffer rapid fouling of the necessarily small passages, leading to bad spray patterns and poor combustion performance. Also, traditionally burners and the nozzles are oversized to exceed the maximum demand. Typically, this is figured as follows. The heating load of the house on the coldest day for the location is considered to define the maximum heat load. The contractor or installer adds to this to provide a safety margin and for future expansion of the house. If the unit is a boiler that provides domestic hot water through the use of a tankless heating coil, the burner capacity is further increased. On the contrary, for a majority of the time, the heating system is satisfying a much smaller load, as only rarely do all these demands add up. Consequently, the average output of the heating system has to be much less than the design capacity and this is accomplished by start and stop cycling operation of the system so that the time-averaged output equals the demand. However, this has been demonstrated to lead to overall efficiencies lower than the steady-state efficiency. Therefore, the two main reasons for the current practice of using oil burners much larger than necessary for space heating are the unavailability of reliable low firing rate oil burners and the desire to assure adequate input rate for short duration, high draw domestic hot water loads. One approach to solve this problem is to develop a burner, which can operate at two firing rates, with the lower rate being significantly lower than 0.5 gallons per hour. This paper describes the initial results of adopting this approach through a pulsed flow nozzle. It has been shown that the concept of flow modulation with a small solenoid valve is feasible. Especially in the second configuration tested, where the Lee valve was integrated with the nozzle, reasonable modulation in flow of the order of 1.7 could be achieved. For this first prototype, the combustion performance is still not quite satisfactory. Improvements in operation, for example by providing a sharp and positive shut-off so that there is no flow under low pressures with consequent poor atomization could lead to better combustion performance. This could be achieved by using nozzles that have shut off or check valves for example. It is recommended that more work in cooperation with the valve manufacturer could produce a technically viable system. Marketability is of course a far more complex problem to be addressed once a technically viable product is available.

KRISHNA,C.R.; BUTCHER,T.A.; KAMATH,B.R.

2004-10-01T23:59:59.000Z

430

Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study  

E-Print Network [OSTI]

Southwest Power Pool Time of Use Pricing Variable Generationresultant costs. Time of use pricing (TOU) rates provide8). For example, time of use (TOU) pricing sends a DR signal

Cappers, Peter

2012-01-01T23:59:59.000Z

431

Energy-Saving Control of Single-Rod Hydraulic Cylinders with Programmable Valves and Improved Working Mode Selection  

E-Print Network [OSTI]

such as the bulk modulus change drastically with changing oil temperature and component wear. In the case-in and meter-out orifices are mechanically linked together in a typical directional control valve-out orifices is well known and has been used in heavy industrial applications for several ye

Yao, Bin

432

Relationship between valve activity, microalgae concentration in the water1 and toxin accumulation in the digestive gland2  

E-Print Network [OSTI]

1 Relationship between valve activity, microalgae concentration in the water1 and toxin harmful microalgae Heterocapsa triquetra (H.t.) were26 exposed to 4 microalgae mixtures at constant total of harmful microalgae on bivalve physiology and ecology; to test the45 putative interest of behavioral change

Brest, Universit de

433

Energy-Saving Adaptive Robust Motion Control of Single-Rod Hydraulic Cylinders with Programmable Valves 1  

E-Print Network [OSTI]

- ety's need for energy conservation while without sacrificing the achievable motion control accuracy that the meter-in and meter-out orifices are mechanically linked together in a typical directional control valve of activities in industry on breaking the mechanical linkage between the meter-in and meter-out orifices

Yao, Bin

434

Selection automatique de variables pertinentes  

E-Print Network [OSTI]

S´election automatique de variables pertinentes Vers la d´ecouverte de nouvelles modalit´es sensori-motrices corr´elations entre ses variables sensori-motrices afin d'apprendre `a r´esoudre sa t^ache d

Boyer, Edmond

435

Parental Time, Behaviors and Childhood Obesity  

E-Print Network [OSTI]

towards child health are modeled and analyzed using instrument variable (IV) methods. Results indicate that the effect of mother's time allocation reduces child weight status. Her decision to allocate time to the child is affected by unseen factors. Father...

Kuteesa, Annette

2012-02-14T23:59:59.000Z

436

Electron-electron interaction, weak localization and spin valve effect in vertical-transport graphene devices  

SciTech Connect (OSTI)

We fabricated a vertical structure device, in which graphene is sandwiched between two asymmetric ferromagnetic electrodes. The measurements of electron and spin transport were performed across the combined channels containing the vertical and horizontal components. The presence of electron-electron interaction (EEI) was found not only at low temperatures but also at moderate temperatures up to ?120?K, and EEI dominates over weak localization (WL) with and without applying magnetic fields perpendicular to the sample plane. Moreover, spin valve effect was observed when magnetic filed is swept at the direction parallel to the sample surface. We attribute the EEI and WL surviving at a relatively high temperature to the effective suppress of phonon scattering in the vertical device structure. The findings open a way for studying quantum correlation at relatively high temperature.

Long, Mingsheng; Gong, Youpin; Wei, Xiangfei; Zhu, Chao; Xu, Jianbao; Liu, Ping; Guo, Yufen; Li, Weiwei; Liu, Liwei, E-mail: lwliu2007@sinano.ac.cn [Key Laboratory of Nanodevices and Applications-CAS and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Liu, Guangtong [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-04-14T23:59:59.000Z

437

Enhanced Component Performance Study: Motor-Operated Valves 19982012  

SciTech Connect (OSTI)

This report presents an enhanced performance evaluation of motor-operated valves (MOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). The MOV failure modes considered are failure to open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the MOV results. Statistically significant decreasing trends were identified for failure to open/close and operation demands.

T. E. Wierman

2013-10-01T23:59:59.000Z

438

Thermal engineering of non-local resistance in lateral spin valves  

SciTech Connect (OSTI)

We study the non-local spin transport in Permalloy/Cu lateral spin valves (LSVs) fabricated on thermally oxidized Si and MgO substrates. While these LSVs show the same magnitude of spin signals, significant substrate dependence of the baseline resistance was observed. The baseline resistance shows much weaker dependence on the inter-electrode distance than that of the spin transport observed in the Cu wires. A simple analysis of voltage-current characteristics in the baseline resistance indicates the observed result can be explained by a combination of the Peltier and Seebeck effects at the injector and detector junctions, suggesting the usage of high thermal conductivity substrate (or under-layer) is effective to reduce the baseline resistance.

Kasai, S., E-mail: KASAI.Shinya@nims.go.jp; Takahashi, Y. K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Hirayama, S.; Mitani, S.; Hono, K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-0006 (Japan); Adachi, H.; Ieda, J.; Maekawa, S. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075 (Japan)

2014-04-21T23:59:59.000Z

439

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

SciTech Connect (OSTI)

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

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

2013-04-16T23:59:59.000Z

440

Preliminary design for hot dirty-gas control-valve test facility. Final report  

SciTech Connect (OSTI)

This report presents the results of a preliminary design and cost estimating effort for a facility for the testing of control valves in Hot Dirty Gas (HDGCV) service. This design was performed by Mittelhauser Corporation for the United States Department of Energy's Morgantown Energy Technology Center (METC). The objective of this effort was to provide METC with a feasible preliminary design for a test facility which could be used to evaluate valve designs under simulated service conditions and provide a technology data base for DOE and industry. In addition to the actual preliminary design of the test facility, final design/construction/operating schedules and a facility cost estimate were prepared to provide METC sufficient information with which to evaluate this design. The bases, assumptions, and limitations of this study effort are given. The tasks carried out were as follows: METC Facility Review, Environmental Control Study, Gas Generation Study, Metallurgy Review, Safety Review, Facility Process Design, Facility Conceptual Layout, Instrumentation Design, Cost Estimates, and Schedules. The report provides information regarding the methods of approach used in the various tasks involved in the completion of this study. Section 5.0 of this report presents the results of the study effort. The results obtained from the above-defined tasks are described briefly. The turnkey cost of the test facility is estimated to be $9,774,700 in fourth quarter 1979 dollars, and the annual operating cost is estimated to be $960,000 plus utilities costs which are not included because unit costs per utility were not available from METC.

Not Available

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure  

SciTech Connect (OSTI)

A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is {approx}37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

Liaw, C.J.; Than, Y.; Tuozzolo, J.

2011-03-28T23:59:59.000Z

442

Enhanced spin signals due to native oxide formation in Ni{sub 80}Fe{sub 20}/Ag lateral spin valves.  

SciTech Connect (OSTI)

Large nonlocal spin valve signals are reported in mesoscopic Ni{sub 80}Fe{sub 20}/Ag lateral spin valves upon exposing them to air. Magnetotransport measurements combined with transmission electron microscopy show that the formation of a native oxide layer at the Ni{sub 80}Fe{sub 20}/Ag interface is responsible for the large signals. The results indicate that lateral spin valves with superior performance to those based on high-resistance tunnel barriers can be achieved via controllable growth of native permalloy oxides.

Mihajlovic, G.; Schreiber, D. K.; Liu, Y.; Pearson, J. E.; Bader, S. D.; Petford-Long, A. K.; Hoffmann, A.; Northwestern Univ.

2010-01-01T23:59:59.000Z

443

Long-term climate variability and abrupt climate change Instructor: Dr. Igor Kamenkovich, associate professor  

E-Print Network [OSTI]

Long-term climate variability and abrupt climate change Instructor: Dr. Igor Kamenkovich, associate students to learn about existing theories of abrupt climate changes and climate variability on time scales of long-term climate variability and abrupt climate change. This course compliments current MPO courses

Miami, University of

444

Quantum information with modular variables  

E-Print Network [OSTI]

We introduce a novel strategy, based on the use of modular variables, to encode and deterministically process quantum information using states described by continuous variables. Our formalism leads to a general recipe to adapt existing quantum information protocols, originally formulated for finite dimensional quantum systems, to infinite dimensional systems described by continuous variables. This is achieved by using non unitary and non-gaussian operators, obtained from the superposition of gaussian gates, together with adaptative manipulations in qubit systems defined in infinite dimensional Hilbert spaces. We describe in details the realization of single and two qubit gates and briefly discuss their implementation in a quantum optical set-up.

A. Ketterer; S. P. Walborn; A. Keller; T. Coudreau; P. Milman

2014-06-24T23:59:59.000Z

445

Calorimeter Process Variable Archiving  

SciTech Connect (OSTI)

These steps were taken to maintain weekly archives: (1) Friday morning you stop the archiver and wait for it to finish writing data (the lock file will be removed from the directory); (2) move the current archive information to a PC via FTP; (3) remove all previous archive information in the previous directory; (4) move the current archive into the previous directory; (5) start a new archive; (6) burn a CDROM of the archive; and (7) copy the current archive to a specific directory. There are 2 ways to check if the Calorimeter Archiver is running, either through the WEB based front end or directly from a command line. Once the archiver is running it can be monitored from a WEB page. This only works with a browser launched from the online machine running the archiver. Each time the browser is reloaded there should be an update reported in the last write check field. You might have to wait a few minutes to see the update. Calorimetry currently takes readings every (300 sec.) 5 minutes. The second method to verify the archiver is running is to issue a command from a Linux cluster machine.

Huffman, David; /Fermilab

2002-01-14T23:59:59.000Z

446

VARIABLE SPEED WIND TURBINE  

E-Print Network [OSTI]

Wind energy is currently the fastest-growing renewable source of energy in India; India is a key market for the wind industry, presenting substantial opportunities for both the international and domestic players. In India the research is carried out on wind energy utilization on big ways.There are still many unsolved challenges in expanding wind power, and there are numerous problems of interest to systems and control researchers. In this paper we study the pitch control mechanism of wind turbine. The pitch control system is one of the most widely used control techniques to regulate the output power of a wind turbine generator. The pitch angle is controlled to keep the generator power at rated power by reducing the angle of the blades. By regulating, the angle of stalling, fast torque changes from the wind will be reutilized. It also describes the design of the pitch controller and discusses the response of the pitch-controlled system to wind velocity variations. The pitch control system is found to have a large output power variation and a large settling time.

Chatinderpal Singh

447

ENSEMBLE VARIABILITY OF NEAR-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI  

SciTech Connect (OSTI)

We present the properties of the ensemble variability V for nearly 5000 near-infrared active galactic nuclei (AGNs) selected from the catalog of Quasars and Active Galactic Nuclei (13th Edition) and the SDSS-DR7 quasar catalog. From three near-infrared point source catalogs, namely, Two Micron All Sky Survey (2MASS), Deep Near Infrared Survey (DENIS), and UKIDSS/LAS catalogs, we extract 2MASS-DENIS and 2MASS-UKIDSS counterparts for cataloged AGNs by cross-identification between catalogs. We further select variable AGNs based on an optimal criterion for selecting the variable sources. The sample objects are divided into subsets according to whether near-infrared light originates by optical emission or by near-infrared emission in the rest frame; and we examine the correlations of the ensemble variability with the rest-frame wavelength, redshift, luminosity, and rest-frame time lag. In addition, we also examine the correlations of variability amplitude with optical variability, radio intensity, and radio-to-optical flux ratio. The rest-frame optical variability of our samples shows negative correlations with luminosity and positive correlations with rest-frame time lag (i.e., the structure function, SF), and this result is consistent with previous analyses. However, no well-known negative correlation exists between the rest-frame wavelength and optical variability. This inconsistency might be due to a biased sampling of high-redshift AGNs. Near-infrared variability in the rest frame is anticorrelated with the rest-frame wavelength, which is consistent with previous suggestions. However, correlations of near-infrared variability with luminosity and rest-frame time lag are the opposite of these correlations of the optical variability; that is, the near-infrared variability is positively correlated with luminosity but negatively correlated with the rest-frame time lag. Because these trends are qualitatively consistent with the properties of radio-loud quasars reported by some previous studies, most of our sample objects are probably radio-loud quasars. Finally, we also discuss the negative correlations seen in the near-infrared SFs.

Kouzuma, S. [School of International Liberal Studies, Chukyo University, Toyota 470-0393 (Japan); Yamaoka, H., E-mail: skouzuma@lets.chukyo-u.ac.jp, E-mail: yamaoka@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

2012-03-01T23:59:59.000Z

448

Automatic flush valve performance (gallons per flush) measured from fixtures in a mixed-use classroom/office building at Texas A&M University  

E-Print Network [OSTI]

flush valve performance (gpf) of fixtures in a mixed use classroom building at Texas A&M University. Water consumption (gpf) among three types of fixtures; low-consumption manual, old optic automatic and improved optic automatic systems are measured...

Lertbannaphong, Salilla

2005-08-29T23:59:59.000Z

449

Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing. Session 1A--Session 2C: Volume 1  

SciTech Connect (OSTI)

The 1994 Symposium on Valve and Pump Testing, jointly sponsored by the Board of Nuclear Codes and Standards of the American Society of Mechanical Engineers and by the Nuclear Regulatory Commission, provides a forum for the discussion of current programs and methods for inservice testing and motor-operated valve testing at nuclear power plants. The symposium also provides an opportunity to discuss the need to improve that testing in order to help ensure the reliable performance of pumps and valves. The participation of industry representatives, regulators, and consultants results in the discussion of a broad spectrum of ideas and perspectives regarding the improvement of inservice testing of pumps and valves at nuclear power plants. This document, Volume 1, covers sessions 1A through session 2C. The individual papers have been cataloged separately.

Not Available

1994-07-01T23:59:59.000Z

450

Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing. Volume 2, Session 3A--Session 4B  

SciTech Connect (OSTI)

The 1994 Symposium on Valve and Pump Testing, jointly sponsored by the Board of Nuclear Codes and Standards of the American Society of Mechanical Engineers and by the Nuclear Regulatory Commission, provides a forum for the discussion of current programs and methods for inservice testing and motor-operated valve testing at nuclear power plants. The symposium also provides an opportunity to discuss the need to improve that testing in order to help ensure the reliable performance of pumps and valves. The participation of industry representatives, regulators, and consultants results in the discussion of a broad spectrum of ideas and perspectives regarding the improvement of inservice testing of pumps and valves at nuclear power plants. Individual papers have been cataloged separately.

Not Available

1994-07-01T23:59:59.000Z

451

Variable metric conjugate gradient methods  

SciTech Connect (OSTI)

1.1 Motivation. In this paper we present a framework that includes many well known iterative methods for the solution of nonsymmetric linear systems of equations, Ax = b. Section 2 begins with a brief review of the conjugate gradient method. Next, we describe a broader class of methods, known as projection methods, to which the conjugate gradient (CG) method and most conjugate gradient-like methods belong. The concept of a method having either a fixed or a variable metric is introduced. Methods that have a metric are referred to as either fixed or variable metric methods. Some relationships between projection methods and fixed (variable) metric methods are discussed. The main emphasis of the remainder of this paper is on variable metric methods. In Section 3 we show how the biconjugate gradient (BCG), and the quasi-minimal residual (QMR) methods fit into this framework as variable metric methods. By modifying the underlying Lanczos biorthogonalization process used in the implementation of BCG and QMR, we obtain other variable metric methods. These, we refer to as generalizations of BCG and QMR.

Barth, T.; Manteuffel, T.

1994-07-01T23:59:59.000Z

452

IS ACTIVE REGION CORE VARIABILITY AGE DEPENDENT?  

SciTech Connect (OSTI)

The presence of both steady and transient loops in active region cores has been reported from soft X-ray and extreme-ultraviolet observations of the solar corona. The relationship between the different loop populations, however, remains an open question. We present an investigation of the short-term variability of loops in the core of two active regions in the context of their long-term evolution. We take advantage of the nearly full Sun observations of STEREO and Solar Dynamics Observatory spacecraft to track these active regions as they rotate around the Sun multiple times. We then diagnose the variability of the active region cores at several instances of their lifetime using EIS/Hinode spectral capabilities. We inspect a broad range of temperatures, including for the first time spatially and temporally resolved images of Ca XIV and Ca XV lines. We find that the active region cores become fainter and steadier with time. The significant emission measure at high temperatures that is not correlated with a comparable increase at low temperatures suggests that high-frequency heating is viable. The presence, however, during the early stages, of an enhanced emission measure in the ''hot'' (3.0-4.5 MK) and ''cool'' (0.6-0.9 MK) components suggests that low-frequency heating also plays a significant role. Our results explain why there have been recent studies supporting both heating scenarios.

Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2012-12-10T23:59:59.000Z

453

Control methods and valve arrangement for start-up and shutdown of pressurized combustion and gasification systems integrated with a gas turbine  

DOE Patents [OSTI]

A power plant having a system for converting coal to power in a gas turbine comprises a coal fed pressurized circulating bed for converting coal to pressurized gases, a gas turbine having a compressor for pressurizing air for the pressurized circulating bed and expander for receiving and expanding hot combustion gases for powering a generator, a first fast acting valve for controlling the pressurized air, a second fast acting valve means for controlling pressurized gas from the compressor to the expander.

Provol, Steve J. (Carlsbad, CA); Russell, David B. (San Diego, CA); Isaksson, Matti J. (Karhula, FI)

1994-01-01T23:59:59.000Z

454

Adhesive bonding using variable frequency microwave energy  

DOE Patents [OSTI]

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Paulauskas, Felix L. (Oak Ridge, TN); Fathi, Zakaryae (Cary, NC); Wei, Jianghua (Raleigh, NC)

1998-01-01T23:59:59.000Z

455

Plasma heating in a variable magnetic field  

SciTech Connect (OSTI)

The problem of particle acceleration in a periodically variable magnetic field that either takes a zero value or passes through zero is considered. It is shown that, each time the field [0]passes through zero, the particle energy increases abruptly. This process can be regarded as heating in the course of which plasma particles acquire significant energy within one field period. This mechanism of plasma heating takes place in the absence of collisions between plasma particles and is analogous to the mechanism of magnetic pumping in collisional plasma considered by Alfven.

Kichigin, G. N., E-mail: king@iszf.irk.ru [Russian Academy of Sciences, Institute of Solar-Terrestrial Physics (Russian Federation)

2013-05-15T23:59:59.000Z

456

Adhesive bonding using variable frequency microwave energy  

DOE Patents [OSTI]

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-09-08T23:59:59.000Z

457

Adhesive bonding using variable frequency microwave energy  

DOE Patents [OSTI]

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-08-25T23:59:59.000Z

458

Temperature dependent nucleation, propagation, and annihilation of domain walls in all-perpendicular spin-valve nanopillars  

SciTech Connect (OSTI)

We present a study of the temperature dependence of the switching fields in Co/Ni-based perpendicularly magnetized spin-valves. While magnetization reversal of all-perpendicular Co/Ni spin valves at ambient temperatures is typically marked by a single sharp step change in resistance, low temperature measurements can reveal a series of resistance steps, consistent with non-uniform magnetization configurations. We propose a model that consists of domain nucleation, propagation, and annihilation to explain the temperature dependence of the switching fields. Interestingly, low temperature (<30?K) step changes in resistance that we associate with domain nucleation have a bimodal switching field and resistance step distribution, attributable to two competing nucleation pathways.

Gopman, D. B., E-mail: daniel.gopman@physics.nyu.edu; Kent, A. D. [Department of Physics, New York University, New York, New York 10003 (United States); Bedau, D. [Department of Physics, New York University, New York, New York 10003 (United States); HGST San Jose Research Center, San Jose, California 95135 (United States); Mangin, S. [Institut Jean Lamour, UMR CNRS 7198 Universit de Lorraine, Nancy, France 54506 (France); Fullerton, E. E. [CMRR, University of California at San Diego, La Jolla, California 92093 (United States); Katine, J. A. [HGST San Jose Research Center, San Jose, California 95135 (United States)

2014-03-21T23:59:59.000Z

459

Dual function armchair graphene nanoribbon-based spin-photodetector: Optical spin-valve and light helicity detector  

SciTech Connect (OSTI)

We show an armchair graphene nanoribbon channel connected between asymmetric ferromagnetic source-drain structurei.e., p-type Co/Au/graphene source and n-type Co/Cu/graphene draincan operate as dual function spin-photodetector, under zero external biases at room temperature. It can function as an optical spin-valve with magnetoresistance of greater than 60% and responsivity as high as 25.12?A/mW, when irradiated by an un-polarized light of energy ?3.03?eV. Under a circularly polarized illumination, this optical spin-valve can also operate as a light helicity detector. The calculated magnetoresistances for right and left circularly polarized lights are both greater than 60%.

Ostovari, Fatemeh [Department of Physics, Tarbiat Modares University, P.O. Box 14115-335, Tehran 1411713116 (Iran, Islamic Republic of); Moravvej-Farshi, Mohammad Kazem, E-mail: Farshi-k@modares.ac.ir [Department of Physics, Tarbiat Modares University, P.O. Box 14115-335, Tehran 1411713116 (Iran, Islamic Republic of); Faculty of Electrical and Computer Engineering, Advanced Devices Simulation Lab (ADSL), Tarbiat Modares University, P.O. Box 14115-194, Tehran 1411713116 (Iran, Islamic Republic of)

2014-08-18T23:59:59.000Z

460

Magnetic field enhancement of non-local spin signal in Ni{<_80}Fe{<_20}/Ag lateral spin valves.  

SciTech Connect (OSTI)

We observe a magnetic-field-induced enhancement of the nonlocal spin signal in Ni{sub 80}Fe{sub 20}/Ag lateral spin valves. The enhancement depends on the bias current polarity but not on the field direction. We present a theoretical model that explains our experimental results, taking into account the electron-spin relaxation of magnetic impurities. We find that the relaxation is about an order of magnitude weaker than Elliott-Yafet relaxation.

Mihajlovic, G.; Erlingsson, S. I.; Vyborny, K.; Pearson, J. E.; Bader, S. D.; Hoffmann, A. (Center for Nanoscale Materials); ( MSD); (Hitachi Global Storage Tech.); (Reykjavik Univ.); (Acad. Sci. Czech Republic)

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

NREL Variability and Reserves Analysis for the Western Interconnect (Presentation)  

SciTech Connect (OSTI)

Additional variability and uncertainty increase reserve requirements. In this light, this presentation discusses how use of generation reserves can be optimized for managing variability and uncertainty. Conclusions of this presentation are: (1) Provided a method for calculating additional reserve requirements due to wind and solar production; (2) Method is based on statistical analysis of historical time series data; (3) Reserves are dynamic, produced for each hour; (4) Reserve time series are calculated from and synchronized to simulation data; (5) PROMOD can not model directly, but workarounds exist for regulation and spin; and (6) Other production modeling packages have varying capability for reserves modeling.

Milligan, M.; King, J.

2011-10-01T23:59:59.000Z

462

Enhanced Component Performance Study: Air-Operated Valves 19982012  

SciTech Connect (OSTI)

This report presents an enhanced performance evaluation of air-operated valves (AOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). Results (beta distributions for failure probabilities upon demand and gamma distributions for rates) are used as inputs to the U.S. Nuclear Regulatory Commission standardized plant analysis risk models of U.S. commercial nuclear power plants. The AOV failure modes considered are failure-to-open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the AOV results. Statistically significant decreasing trends were identified in two areas: AOV operation demands less than or equal to 20 demands per year and greater than 20 demands.

T. E. Wierman

2013-10-01T23:59:59.000Z

463

Heat generation by electronic current in a quantum dot spin-valve  

SciTech Connect (OSTI)

Electric-current-induced heat generation in an interacting single-level quantum dot connected to ferromagnetic leads with noncollinear magnetizations is theoretically investigated. We find that when the two leads' spin polarization rates are identical and much smaller than unit, the magnitude of the heat generation is almost monotonously enhanced as the angle between the leads' magnetic moments is varied from zero to ?, while the magnitude of the electric current is continuously suppressed. Moreover, the properties of the heat generation depend on the lead's spin polarization rate in different ways when the angle is varied. If at least one of the leads' spin polarization rate approaches to unit, the spin-valve effect of the heat generation is identical to that of the electric current. Now the previously found negative differential of the heat generation disappears when the angle approaches to ?. As compared to the current, the heat generation is more sensitive to the system's asymmetry when one of the electrodes is half-metallic in noncollinear configurations.

Chi, Feng [School of Physical Science and Technology, Inner Mongolia University, Huhehaote 010023 (China); College of Engineering, Bohai University, Jinzhou 121013 (China); Sun, Lian-Liang [College of Science, North China University of Technology, Beijing 100041 (China); Guo, Yu [College of Engineering, Bohai University, Jinzhou 121013 (China)

2014-10-28T23:59:59.000Z

464

Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner  

SciTech Connect (OSTI)

An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

Cho, Soo-Yong [Department of Mechanical and Aerospace Engineering (ReCAPT), Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Cho, Chong-Hyun [School of Mechanical and Aerospace Engineering, Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Kim, Chaesil [Department of Mechanical Engineering, Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea)

2008-09-15T23:59:59.000Z

465

Variable Interactions in Query-Driven Visualization  

SciTech Connect (OSTI)

One fundamental element of scientific inquiry is discoveringrelationships, particularly the interactions between different variablesin observed or simulated phenomena. Building upon our prior work in thefield of Query-Driven Visualization, where visual data analysisprocessing is focused on subsets of large data deemed to be"scientifically interesting," this new work focuses on a novel knowledgediscovery capability suitable for use with petascale class datasets. Itenables visual presentation of the presence or absence of relationships(correlations) between variables in data subsets produced by Query-Drivenmethodologies. This technique holds great potential for enablingknowledge discovery from large and complex datasets currently emergingfrom SciDAC and INCITE projects. It is sufficiently generally to beapplicable to any time of complex, time-varying, multivariate data fromstructured, unstructured or adaptive grids.

Bethel, E. Wes; Gosink, Luke J.; Anderson, John C.; Joy, Kenneth I.

2007-10-25T23:59:59.000Z

466

Dynamical dark energy or variable cosmological parameters?  

E-Print Network [OSTI]

One of the main aims in the next generation of precision cosmology experiments will be an accurate determination of the equation of state (EOS) for the dark energy (DE). If the latter is dynamical, the resulting barotropic index \\omega should exhibit a non-trivial evolution with the redshift. Usually this is interpreted as a sign that the mechanism responsible for the DE is related to some dynamical scalar field, and in some cases this field may behave non-canonically (phantom field). Present observations seem to favor an evolving DE with a potential phantom phase near our time. In the literature there is a plethora of dynamical models trying to describe this behavior. Here we show that the simplest option, namely a model with a variable cosmological term, \\Lambda=\\Lambda(t), leads in general to a non-trivial effective EOS, with index \\omega_e, which may naturally account for these data features. We prove that in this case there is always a ``crossing'' of the \\omega_e=-1 barrier near our time. We also show how this effect is modulated (or even completely controled) by a variable Newton's constant G=G(t).

Joan Sola; Hrvoje Stefancic

2005-12-21T23:59:59.000Z

467

Blazar Variability and Evolution in the GeV Regime  

E-Print Network [OSTI]

One of the most important problem of the blazar astrophysics is to understand the physical origin of the blazar sequence. In this study, we focus on the GeV gamma-ray variability of blazars and evolution perspective we search the relation between the redshift and the variability amplitude of blazars for each blazar subclass. We analyzed the Fermi-LAT data of the TeV blazars and the bright AGNs (flux $\\geq$ 4$\\times10^{-9}$ cm$^{-2}$s$^{-1}$) selected from the 2LAC (the 2nd LAT AGN catalog) data base. As a result, we found a hint of the correlation between the redshift and the variability amplitude in the FSRQs. Furthermore the BL Lacs which have relatively lower peak frequency of the synchrotron radiation and relatively lower redshift, have a tendency to have a smaller variability amplitude.

Tsujimoto, S; Nishijima, K; Kodani, K

2015-01-01T23:59:59.000Z

468

Operating Reserves and Variable Generation  

SciTech Connect (OSTI)

This report tries to first generalize the requirements of the power system as it relates to the needs of operating reserves. It also includes a survey of operating reserves and how they are managed internationally in system operations today and then how new studies and research are proposing they may be managed in the future with higher penetrations of variable generation.

Ela, E.; Milligan, M.; Kirby, B.

2011-08-01T23:59:59.000Z

469

Entropic Time  

SciTech Connect (OSTI)

The formulation of quantum mechanics within the framework of entropic dynamics includes several new elements. In this paper we concentrate on one of them: the implications for the theory of time. Entropic time is introduced as a book-keeping device to keep track of the accumulation of changes. One new feature is that, unlike other concepts of time appearing in the so-called fundamental laws of physics, entropic time incorporates a natural distinction between past and future.

Caticha, Ariel [Department of Physics, University at Albany-SUNY, Albany, NY 12222 (United States)

2011-03-14T23:59:59.000Z

470

Fast Bayesian Variable Selection Algorithms for High Dimensional Genomics Data  

E-Print Network [OSTI]

Anderson Cancer Center, USA Abstract Large-scale molecular genomics assays such as gene and micro of many diseases, especially cancer. However, the solution to such a problem requires exploring a large predict survival times of patients with brain cancer. Our method finds small sets of variables

Ordonez, Carlos

471

Variable frequency microwave heating apparatus  

DOE Patents [OSTI]

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN); Johnson, Arvid C. (Lake in the Hills, IL); Thigpen, Larry T. (Angier, NC)

1999-01-01T23:59:59.000Z

472

Massive Variability Surveys from Venezuela  

E-Print Network [OSTI]

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Cesar Briceno

2003-04-03T23:59:59.000Z

473

Review of Probability Random Variable  

E-Print Network [OSTI]

at close 4) Height of wheel going over a rocky road #12;3 Random Variable Non-examples 1) `Heads' or `Tails' on coin 2) Red or Black ball from urn But we can make these into RV's Basic Idea ­ don't know · Temperature · Wheel height #12;5 Given Continuous RV X... What is the probability that X = x0 ? Oddity : P

Fowler, Mark

474

Blasthole timing control vibration, airblast and flyrock  

SciTech Connect (OSTI)

The authors say there is more to proper blasthole design than sequencing holes. Timing is one of the most important blast design variables. Timing controls the fragmentation size, piling of the broken material, maximum vibration level, airblast, flyrock, backbreak, endbreak and general overbreak. The authors explain how each of these items is controlled by timing.

Konya, C.J.; Walter, E.J.

1988-01-01T23:59:59.000Z

475

A PHOTOMETRICALLY AND MORPHOLOGICALLY VARIABLE INFRARED NEBULA IN L483  

SciTech Connect (OSTI)

We present narrow and broad K-band observations of the Class 0/I source IRAS 18148-0440 that span 17 years. The infrared nebula associated with this protostar in the L483 dark cloud is both morphologically and photometrically variable on a timescale of only a few months. This nebula appears to be an infrared analog to other well known optically visible variable nebulae associated with young stars, such as Hubble's Variable Nebula. Along with Cepheus A, this is one of the first large variable nebulae to be found that is only visible in the infrared. The variability of this nebula is most likely due to changing illumination of the cloud rather than any motion of the structure in the nebula. Both morphological and photometric changes are observed on a timescale only a few times longer than the light crossing time of the nebula, suggesting very rapid intrinsic changes in the illumination of the nebula. Our narrowband observations also found that H{sub 2} knots are found nearly twice as far to the east of the source as to its west, and that H{sub 2} emission extends farther east of the source than the previously known CO outflow.

Connelley, Michael S. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Hodapp, Klaus W. [University of Hawaii Institute for Astronomy, 640 N. Aohoku Pl., Hilo, HI 96720 (United States); Fuller, Gary A. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester, Manchester, M13 9PL (United Kingdom)

2009-03-15T23:59:59.000Z

476

WECC Variable Generation Planning Reference Book  

SciTech Connect (OSTI)

This planning reference book is a document reflecting a Western Electricity Coordination Council (WECC) effort to put together multiple sources of information and provide a clear, systemic, comprehensive outline of the problems, both existing and anticipated; their impacts on the system; currently used and proposed solutions by the industry and research community; planning practices; new technologies, equipment, and standards; and expected future trends. This living (periodically updated) document could help WECC and other practicing engineers, especially the younger generation of engineers joining the workforce, to get familiar with a large variety of information related to the integration of variable resources into the WECC system, bypassing in part the need for time-consuming information gathering and learning processes from more experienced engineers or from the literature.

Makarov, Yuri V.; Du, Pengwei; Etingov, Pavel V.; Ma, Jian; Vyakaranam, Bharat

2013-05-14T23:59:59.000Z

477

Improvements of the Variable Thermal Resistance  

E-Print Network [OSTI]

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

Szkely, V; Kollar, E

2008-01-01T23:59:59.000Z

478

Improvements of the Variable Thermal Resistance  

E-Print Network [OSTI]

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

V. Szekely; S. Torok; E. Kollar

2008-01-07T23:59:59.000Z

479

Continuous variable entanglement dynamics in structured reservoirs  

E-Print Network [OSTI]

We address the evolution of entanglement in bimodal continuous variable quantum systems interacting with two independent structured reservoirs. We derive an analytic expression for the entanglement of formation without performing the Markov and the secular approximations and study in details the entanglement dynamics for various types of structured reservoirs and for different reservoir temperatures, assuming the two modes initially excited in a twin-beam state. Our analytic solution allows us to identify three dynamical regimes characterized by different behaviors of the entanglement: the entanglement sudden death, the non-Markovian revival and the non-secular revival regimes. Remarkably, we find that, contrarily to the Markovian case, the short-time system-reservoir correlations in some cases destroy quickly the initial entanglement even at zero temperature.

R. Vasile; S. Olivares; M. G. A. Paris; S. Maniscalco

2009-10-13T23:59:59.000Z

480

The effects of compressor speed and electronic expansion valve opening on the optimum design of inverter heat pump at various heating loads  

SciTech Connect (OSTI)

The experiments to design the optimum operation point of an inverter heat pump were performed by varying compressor speed and expansion valve opening for various heating loads. At the indoor temperatures of {minus}5 {approximately} 15C and outdoor temperatures of {minus}10 {approximately} 25 C, the compressor driving frequencies were varied 10 {approximately} 120 Hz and 80 {approximately} 200 pulse for the expansion valve opening while the speed of the indoor and outdoor fans were fixed. From the results of this study, the optimum combination of compressor driving frequency and expansion valve opening were found to exist if indoor and outdoor temperatures are settled though the operation point is changed by the preferable factor among capacity, comfort and power saving.

Hwang, Y.; Kim, Y.; Park, J.; Kim, C.

1999-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable valve timing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Variable flexure-based fluid filter  

DOE Patents [OSTI]

An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.

Brown, Steve B.; Colston Jr., Billy W.; Marshall, Graham; Wolcott, Duane

2007-03-13T23:59:59.000Z

482

Principal Components Instrumental Variable Estimation  

E-Print Network [OSTI]

of the main results are displayed in two appendices. 2 Econometric Framework Consider the simultaneous equations model y = X? + u and X = Z?+ V , (1) 1 An advantage of such general structure is that the large-sample condition used in previous studies Kn/ p n... ? 0, where Kn is the number of instruments and n is the sample size, is not required in our asymptotic approximations. 4 where y is the n 1 vector containing n observations of the dependent variable; X is the n G matrix with observations...

Winkelried, Diego; Smith, Richard J.

2011-01-31T23:59:59.000Z

483

Variable Average Absolute Percent Differences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism inS-4500II FieldVacancy-InducedCloudPoissonVampire Power1 -Variable

484

Interannual variability in tropospheric nitrous oxide  

E-Print Network [OSTI]

Observations of tropospheric N2O mixing ratio show significant variability on interannual timescales (0.2?ppb, 1 standard deviation). We found that interannual variability in N2O is weakly correlated with that in CFC-12 ...

Thompson, R. L.

485

Utility Variable Generation Integration Group Fall Technical...  

Broader source: Energy.gov (indexed) [DOE]

Technical Workshop Utility Variable Generation Integration Group Fall Technical Workshop October 15, 2014 9:00AM CDT to October 17, 2014 3:00PM CDT The Utility Variable Generation...

486

Invariant formulation for dispersed transverse isotropy in aortic heart valves: An efficient means for modeling fiber splay  

SciTech Connect (OSTI)

Most soft tissues possess an oriented architecture of collagen fiber bundles, conferring both anisotropy and nonlinearity to their elastic behavior. Transverse isotropy has often been assumed for a subset of these tissues that have a single macroscopically-identifiable preferred fiber direction. Micro-structural studies, however, suggest that, in some tissues, collagen fibers are approximately normally distributed about a mean preferred fiber direction. Structural constitutive equations that account for this dispersion of fibers have been shown to capture the mechanical complexity of these tissues quite well. Such descriptions, however, are computationally cumbersome for two-dimensional (2D) fiber distributions, let alone for fully three-dimensional (3D) fiber populations. In this paper, we develop a new constitutive law for such tissues, based on a novel invariant theory for dispersed transverse isotropy. The invariant theory is based on a novel closed-form ''splay invariant'' that can easily handle 3D fiber populations, and that only requires a single parameter in the 2D case. The model is polyconvex and fits biaxial data for aortic valve tissue as accurately as the standard structural model. Modification of the fiber stress-strain law requires no re-formulation of the constitutive tangent matrix, making the model flexible for different types of soft tissues. Most importantly, the model is computationally expedient in a finite-element analysis, demonstrated by modeling a bioprosthetic heart valve.

Freed, Alan D.; Einstein, Daniel R.; Vesely, Ivan

2005-11-01T23:59:59.000Z

487

Variable frequency microwave furnace system  

DOE Patents [OSTI]

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

488

Variable frequency microwave furnace system  

DOE Patents [OSTI]

A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

Bible, D.W.; Lauf, R.J.

1994-06-14T23:59:59.000Z

489

Integration of Variable Generation and Cost-Causation (Fact Sheet)  

SciTech Connect (OSTI)

Variable renewable energy generation sources, such as wind and solar energy, provide benefits such as reduced environmental impact, zero fuel consumption, and low and stable costs. Advances in both technologies can reduce capital costs and provide significant control capabilities. However, their variability and uncertainty - which change with weather conditions, time of day, and season - can cause an increase in power system operating costs compared to a fully controllable power plant. Although a number of studies have assessed integration costs, calculating them correctly is challenging because it is difficult to accurately develop a baseline scenario without variable generation that properly accounts for the energy value. It is also difficult to appropriately allocate costs given the complex, nonlinear interactions between resources and loads.

Not Available

2012-09-01T23:59:59.000Z

490

The role of an accretion disk in AGN variability  

E-Print Network [OSTI]

Optically thick accretion disks are considered to be important ingredients of luminous AGN. The claim of their existence is well supported by observations and recent years brought some progress in understanding of their dynamics. However, the role of accretion disks in optical/UV/X-ray variability of AGN is not quite clear. Most probably, in short timescales the disk reprocesses the variable X-ray flux but at longer timescales the variations of the disk structure lead directly to optical/UV variations as well as affect, or even create, the X-ray variability pattern. We urgently need a considerable progress in time-dependent disk models to close the gap between the theory and the stream of data coming from the AGN monitoring.

B. Czerny

2004-09-10T23:59:59.000Z

491

Wind Power Variability, Its Cost, and Effect on Power Plant Emissions  

E-Print Network [OSTI]

Wind Power Variability, Its Cost, and Effect on Power Plant Emissions A Dissertation Submitted The recent growth in wind power is transforming the operation of electricity systems by introducing. As a result, system operators are learning in real-time how to incorporate wind power and its variability

492

Increased network efficiency for variable rate video streams in an Integrated Services Packet Network environment  

E-Print Network [OSTI]

with a way to reserve a fixed quantity of network resources for their exclusive use. Most video encoders, however, are variable rate. This research describes a mechanism by which variable bit-rate, real-time video streams can be sent over a fixed rate...

Schroeder, Charles Grant

1996-01-01T23:59:59.000Z

493

Optimization of time-based rates in forward energy markets  

E-Print Network [OSTI]

This paper presents a new two-step design approach of Time-Based Rate (TBR) programs for markets with a high penetration of variable energy sources such as wind power. First, an optimal market time horizon must be determined ...

Wang, J.

494

Optimal adaptive routing and traffic assignment in stochastic time-dependent networks  

E-Print Network [OSTI]

A stochastic time-dependent (STD) network is defined by treating all link travel times at all time periods as random variables, with possible time-wise and link-wise stochastic dependency. A routing policy is a decision ...

Gao, Song, 1976-

2005-01-01T23:59:59.000Z

495

Variable ratio regenerative braking device  

DOE Patents [OSTI]

Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.

Hoppie, Lyle O. (Birmingham, MI)

1981-12-15T23:59:59.000Z

496