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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

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

2

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

DOE Green Energy (OSTI)

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

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

1994-11-18T23:59:59.000Z

3

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

4

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

SciTech Connect

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

5

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

SciTech Connect

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

6

VARIABLE TIME DELAY MEANS  

DOE Patents (OSTI)

An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

Clemensen, R.E.

1959-11-01T23:59:59.000Z

7

VARIABLE TIME-INTERVAL GENERATOR  

DOE Patents (OSTI)

This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

Gross, J.E.

1959-10-31T23:59:59.000Z

8

Parametric time?frequency estimation of prosthetic heart valve sounds  

Science Conference Proceedings (OSTI)

Prosthetic heart valves have been responsible for extending the life spans and improving the quality of life of many people with serious heart conditions. Even though the heart valves are extremely reliable

D. E. Perkins; G. H. Thomas; G. A. Clark

1998-01-01T23:59:59.000Z

9

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

E-Print Network (OSTI)

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

Miller, Justin (Justin Lee)

2011-01-01T23:59:59.000Z

10

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

11

Mesoscale Time and Space Wind Variability  

Science Conference Proceedings (OSTI)

The results of a program to study the time and space variability of the wind field below 5 km are presented. Wind data were collected using pilot balloons tracked with the METRAC positioning system. Balloons were launched at 10-30 min intervals ...

W. H. Jasperson

1982-06-01T23:59:59.000Z

12

Safety valve  

SciTech Connect

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

13

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

SciTech Connect

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

14

Simulating Random Natural Variability in Time-Varying Atmospheric...  

NLE Websites -- All DOE Office Websites (Extended Search)

Natural Variability in Time-Varying Atmospheric Concentrations of Toxic Gas from Pipeline Ruptures Speaker(s): David J. Wilson Date: February 4, 2004 - 12:00pm Location: Bldg....

15

Plug valve  

SciTech Connect

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

Wordin, J.J.

1989-11-07T23:59:59.000Z

16

Plug valve  

DOE Patents (OSTI)

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

Wordin, John J. (Shelley, ID)

1989-01-01T23:59:59.000Z

17

Simulating Random Natural Variability in Time-Varying Atmospheric  

NLE Websites -- All DOE Office Websites (Extended Search)

Simulating Random Natural Variability in Time-Varying Atmospheric Simulating Random Natural Variability in Time-Varying Atmospheric Concentrations of Toxic Gas from Pipeline Ruptures Speaker(s): David J. Wilson Date: February 4, 2004 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Jeiwon Deputy Random time series are found everywhere in nature. The Brownian motion of small particles; the price of assets (stocks) in financial markets; the diffusion of individual molecules through a membrane; the ballistic deposition of nano-particles onto a lattice substrate; and the time-varying concentration fluctuations at a point downwind from a pollution source all have a common dynamic description. All are stochastic processes where the local rate of change of the variable has a natural drift back to some equilibrium state, combined with a random fluctuating component. We will

18

Time Scale and Feedback of Zonal-Mean-Flow Variability  

Science Conference Proceedings (OSTI)

The physical processes that determine the time scale of zonal-mean-flow variability are examined with an idealized numerical model that has a zonally symmetric lower boundary. In the part of the parameter space where the time-mean zonal flow is ...

Seok-Woo Son; Sukyoung Lee; Steven B. Feldstein; John E. Ten Hoeve

2008-03-01T23:59:59.000Z

19

Non-flat time-variable dark energy cosmology  

E-Print Network (OSTI)

We generalize the time-variable dark energy scalar field $\\Phi$ model ($\\Phi$CDM) to non-flat space. We show that even in the space-curvature-dominated epoch the scalar field solution is a time-dependent fixed point or attractor, with scalar field energy density that grows relative to the energy density in spatial curvature. This is the first example of a physically consistent and complete model of dynamical dark energy in a non-flat geometry.

Pavlov, Anatoly; Saaidi, Khaled; Ratra, Bharat

2013-01-01T23:59:59.000Z

20

Fast valve  

DOE Patents (OSTI)

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

Van Dyke, W.J.

1992-04-07T23:59:59.000Z

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.


21

Fast valve  

DOE Patents (OSTI)

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

Van Dyke, William J. (Grafton, VA)

1992-01-01T23:59:59.000Z

22

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

23

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

24

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

25

Compile-time Derivation of Variable Dependency Using Abstract Interpretation  

E-Print Network (OSTI)

Traditional schemes for abstract interpretation-based global analysis of logic programs generally focus on obtaining procedure argument mode and type information. Variable sharing information is often given only the attention needed to preserve the correctness of the analysis. However, such sharing information can be very useful. In particular, it can be used for predicting runtime goal independence, which can eliminate costly run-time checks in and-parallel execution. In this paper, a new algorithm for doing abstract interpretation in logic programs is described which concentrates on inferring the dependencies of the terms bound to program variables with increased precision and at all points in the execution of the program, rather than just at a procedure level. Algorithms are presented for computing abstract entry and success substitutions which extensively domain independent fixpoint algorithm is presented and described in detail. The algorithms are illustrated with examples. Finally, results from an implementation of the abstract interpreter are presented. 1

K. Muthukumar; M. Hermenegildo

1992-01-01T23:59:59.000Z

26

An approach for modeling the valve train system to control the homogeneous combustion in a compression ignition engine  

Science Conference Proceedings (OSTI)

This paper presents an approach for modeling the valve train system to obtain a homogeneous charge compression ignition (HCCI) engine from a gasoline engine. The HCCI engines use different indirect strategies to control the start of the combustion. The ... Keywords: exhaust gas recirculation, homogeneous charge compression ignition, variable valve timing

Radu Cosgarea; Corneliu Cofaru; Mihai Aleonte; Maria Luminita Scutaru; Liviu Jelenschi; Gabriel Sandu

2011-04-01T23:59:59.000Z

27

Low noise control valve  

SciTech Connect

Noise is one of the problems associated with the use of any type of control valve in systems involving the flow of fluids. The advent of OSHA standards has prompted control valve manufacturers to design valves with special trim to lower the sound pressure level to meet these standards. However, these levels are in some cases too high, particularly when a valve must be located in or near an area where people are working at tasks requiring a high degree of concentration. Such locations are found around and near research devices and in laboratory-office areas. This paper describes a type of fluid control device presently being used at PPL as a bypass control valve in deionized water systems and designed to reduce sound pressure levels considerably below OSHA standards. Details of the design and construction of this constant pressure drop variable flow control valve are contained in the text and are shown in photographs and drawings. Test data taken are included. (auth)

Christie, R.S.

1975-01-01T23:59:59.000Z

28

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

29

DETECTING VARIABILITY IN MASSIVE ASTRONOMICAL TIME-SERIES DATA. II. VARIABLE CANDIDATES IN THE NORTHERN SKY VARIABILITY SURVEY  

SciTech Connect

We present variability analysis of data from the Northern Sky Variability Survey (NSVS). Using the clustering method, which defines variable candidates as outliers from large clusters, we cluster 16,189,040 light curves having data points at more than 15 epochs as variable and non-variable candidates in 638 NSVS fields. Variable candidates are selected depending on how strongly they are separated from the largest cluster and how rarely they are grouped together in eight-dimensional space spanned by variability indices. All NSVS light curves are also cross-correlated with IRAS, AKARI, Two Micron All Sky Survey, Sloan Digital Sky Survey (SDSS), and GALEX objects, as well as known objects in the SIMBAD database. The variability analysis and cross-correlation results are provided in a public online database, which can be used to select interesting objects for further investigation. Adopting conservative selection criteria for variable candidates, we find about 1.8 million light curves as possible variable candidates in the NSVS data, corresponding to about 10% of our entire NSVS sample. Multi-wavelength colors help us find specific types of variability among the variable candidates. Moreover, we also use morphological classification from other surveys such as SDSS to suppress spurious cases caused by blending objects or extended sources due to the low angular resolution of the NSVS.

Shin, Min-Su [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Yi, Hahn; Kim, Dae-Won; Chang, Seo-Won [Department of Astronomy, Yonsei University, Seoul 120-749 (Korea, Republic of); Byun, Yong-Ik, E-mail: msshin@umich.edu, E-mail: yihahn@galaxy.yonsei.ac.kr, E-mail: dakim@cfa.harvard.edu, E-mail: seowony@galaxy.yonsei.ac.kr, E-mail: ybyun@yonsei.ac.kr [Department of Astronomy and University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-03-15T23:59:59.000Z

30

The Discrete Variable Method for the Time Dependent and ...  

Science Conference Proceedings (OSTI)

... Abstract: The discrete variable representation (DVR) has been found to be a very effective approach for the numerical solution of the Schroedinger ...

2011-01-12T23:59:59.000Z

31

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

32

Plasma valve  

DOE Patents (OSTI)

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

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

2003-01-01T23:59:59.000Z

33

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

34

Variability of SpaceTime Mean Rain Rate  

Science Conference Proceedings (OSTI)

A mixed lognormal distribution is fit to rain-rate data for the purpose of estimating the spacetime mean. Using Fisher information, the large sample variance is obtained for grouped and ungrouped data estimates. The asymptotic variance results ...

B. Kedem; R. Pfeiffer; D. A. Short

1997-05-01T23:59:59.000Z

35

Multi-Scale Kernel Latent Variable Models for Nonlinear Time Series Pattern Matching  

Science Conference Proceedings (OSTI)

In this paper we propose a method for nonlinear time series pattern matching: "Multi-Scale Kernel Latent Variable (MSKLV) models". The pattern matching methodology includes multi-scale analysis using wavelet decomposition of time series and finding latent ...

B. Venkataramana Kini; C. Chandra Sekhar

2008-01-01T23:59:59.000Z

36

Real-Time Operational Forecasting on Shipboard of the Iceland-Faeroe Frontal Variability  

Science Conference Proceedings (OSTI)

Real-time operational shipboard forecasts of Iceland-Faeroe frontal variability were executed for the first time with a primitive equation mode. High quality, intensive hydrographic surveys during August 1993 were used for initialization, ...

A. R. Robinson; H. G. Arango; W. G. Leslie; A. J. Miller; A. Warn-Varnas; P-M. Poulain

1996-02-01T23:59:59.000Z

37

Modeling the Variability of Drop Size Distributions in Space and Time  

Science Conference Proceedings (OSTI)

The information on the time variability of drop size distributions (DSDs) as seen by a disdrometer is used to illustrate the structure of uncertainty in radar estimates of precipitation. Based on this, a method to generate the spacetime ...

Gyu Won Lee; Alan W. Seed; Isztar Zawadzki

2007-06-01T23:59:59.000Z

38

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

39

Time Series Photometry of Variable Stars in the Globular Cluster NGC 6397  

E-Print Network (OSTI)

Time series BVI photometry is presented for 16 short-period variables located in the central region of the globular cluster NGC 6397. The sample includes 9 newly detected variables. The light curve of cataclysmic variable CV6 shows variability with a period of 0.2356 days. We confirm an earlier reported period of 0.472 days for cataclysmic variable CV1. Phased light curves of both CVs exhibit sine-like light curves, with two minima occurring during each orbital cycle. The secondary component of CV1 has a low average density of 0.83 g/cm^{3} indicating that it cannot be a normal main sequence star. Variables among the cluster blue stragglers include a likely detached eclipsing binary with orbital period of 0.787 days, three new SX Phe stars (one of which has the extremely short period of 0.0215 days), and three low amplitude variables which are possible gamma Doradus variables.

Janusz Kaluzny; Ian B. Thompson

2002-10-29T23:59:59.000Z

40

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

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

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

42

Improved plug valve  

DOE Patents (OSTI)

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

Wordin, J.J.

1986-05-09T23:59:59.000Z

43

Rotary pneumatic valve  

DOE Patents (OSTI)

A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle. 4 figs.

Hardee, H.C.

1989-08-02T23:59:59.000Z

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.

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

1999-04-27T23:59:59.000Z

45

Vacuum breaker valve assembly  

Science Conference Proceedings (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

46

Medium Lead-Time Predictability of Intraseasonal Variability of Rainfall in West Africa  

Science Conference Proceedings (OSTI)

The variability of the West African monsoon on the intraseasonal time scale is a major issue for agricultural strategy, as the occurrence of dry spells can strongly impact yields of rain-fed crops. This study investigates this intraseasonal ...

Benjamin Sultan; Serge Janicot; Cyrille Correia

2009-06-01T23:59:59.000Z

47

Validation of the SpaceTime Variability of African Easterly Waves Simulated by the CNRM GCM  

Science Conference Proceedings (OSTI)

The ability of the Centre National de Recherches Mtorologiques (CNRM) general circulation model (GCM) to properly simulate the spacetime variability of the African easterly waves (AEWs) has been examined over the period 198288. The relative ...

J. P. Cron; J. F. Gurmy

1999-09-01T23:59:59.000Z

48

SpaceTime Variability of Rainfall and Extreme Flood Response in the Menomonee River Basin, Wisconsin  

Science Conference Proceedings (OSTI)

The hydrometeorological processes that control flash flooding are examined through analyses of spacetime rainfall variability and flood response in the Milwaukee metropolitan region. The analyses focus on four flood events in the Menomonee River ...

Yu Zhang; James A. Smith

2003-06-01T23:59:59.000Z

49

Real-Time Monitoring and Prediction of Modes of Coherent Synoptic to Intraseasonal Tropical Variability  

Science Conference Proceedings (OSTI)

A technique of near-real-time monitoring and prediction of various modes of coherent synoptic to intraseasonal zonally propagating tropical variability is developed. It involves Fourier filtering of a daily updated global dataset for the specific ...

Matthew Wheeler; Klaus M. Weickmann

2001-11-01T23:59:59.000Z

50

Acoustic classification of the state of artificial heart valves  

Science Conference Proceedings (OSTI)

Transthoracic acoustic signals from BSCC (BjrkShiley convexoconcave) mechanical heart valves implanted in human patients were processed to determine if the valves had separated outflow struts. For normal valves with intact outflow struts it is demonstrated that a time?windowed spectral analysis reveals the resonant frequency of the vibrating strut. The strut

Terry D. Plemons; Michael Hovenga

1995-01-01T23:59:59.000Z

51

Variable-delay feedback control of unstable steady states in retarded time-delayed systems  

E-Print Network (OSTI)

We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

Aleksandar Gjurchinovski; Viktor Urumov

2010-07-06T23:59:59.000Z

52

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

53

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

54

Equations Governing Space-Time Variability of Liquid Water Path in Stratus Clouds  

NLE Websites -- All DOE Office Websites (Extended Search)

Equations Governing Space-Time Variability of Equations Governing Space-Time Variability of Liquid Water Path in Stratus Clouds K. Ivanova Pennsylvania State University University Park, Pennsylvania T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington M. Ausloos University of Liège B-4000 Liège, Belgium Abstract We present a method on how to derive an underlying mathematical (statistical or model free) equation for a liquid water path (LWP) signal directly from empirical data. The evolution of the probability density functions (PDFs) from small to large time scales is explicitly derived in the framework of Fokker-Planck equation. A drift and a diffusion term describing the deterministic and stochastic influences on the non-Gaussian fat tails of the liquid water probability distributions are obtained from

55

By-pass valve  

Science Conference Proceedings (OSTI)

An improved by-pass valve (1) for use in an automobile exhaust system (Es) comprises an air inlet (7) connected to an air pump (Ap), first and second air outlets (15,23) respectively connected to first and second portions (P1,p2) of a catalytic converter (Cc) and a third outlet (33) through which air is dumped to atmosphere. Air is directed from the inlet to the first outlet when engine temperature is less than a predetermined value and from the inlet to the second outlet when engine temperature reaches the predetermined value. A first and normally closed valve (81) is intermediate the air inlet and the first and second outlets and a second and normally open valve (83) is intermediate the air inlet and the third outlet. The first valve is opened and the second valve closed when engine vacuum exceeds a predetermined level so air flows to either the first or second outlet. The second valve is reopened whenever the outlet to which air is directed is blocked so air is dumped to atmosphere. To accomplish this, the first valve is mounted on the first section (111) of a split shaft (109) and the second valve is mounted on a second shaft section (113). The sections are movable in unison to open the first valve, but the second section is movable relative to the first section when a blockage occurs to reopen the second valve.

Williamson, R.E.

1981-01-06T23:59:59.000Z

56

Solid handling valve  

DOE Patents (OSTI)

The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

Williams, William R. (Morgantown, WV)

1979-01-01T23:59:59.000Z

57

Compact gate valve  

DOE Patents (OSTI)

This invention relates to a double-disc gate valve which is compact, comparatively simple to construct, and capable of maintaining high closing pressures on the valve discs with low frictional forces. The valve casing includes axially aligned ports. Mounted in the casing is a sealed chamber which is pivotable transversely of the axis of the ports. The chamber contains the levers for moving the valve discs axially, and an actuator for the levers. When an external drive means pivots the chamber to a position where the discs are between the ports and axially aligned therewith, the actuator for the levers is energized to move the discs into sealing engagement with the ports.

Bobo, Gerald E. (Knoxville, TN)

1977-01-01T23:59:59.000Z

58

Tubing drain valve  

SciTech Connect

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

Soderberg, P.B.

1987-02-24T23:59:59.000Z

59

Modeling the Effect of Land Surface Evaporation Variability on Precipitation Variability. Part II: Time- and Space-Scale structure  

Science Conference Proceedings (OSTI)

This is the second of a two-part article investigating the impact of variations of land surface evaporability on the interannual variability of precipitation. The first goal of this part is to analyze the relationship between the atmospheric ...

Oreste Reale; Paul Dirmeyer; Adam Schlosser

2002-08-01T23:59:59.000Z

60

Multidimensional time-dependent discrete variable representations in multiconfiguration Hartree calculations  

SciTech Connect

In the multiconfiguration time-dependent Hartree (MCTDH) approach, the wave function is expanded in time-dependent basis functions, called single-particle functions, to increase the efficiency of the wave-packet propagation. The correlation discrete variable representation (CDVR) approach, which is based on a time-dependent discrete variable representation (DVR), can be employed to evaluate matrix elements of the potential energy. The efficiency of the MCTDH method can be further enhanced by using multidimensional single-particle functions. However, up to now the CDVR approach could not be used in MCTDH calculations employing multidimensional single-particle functions, since this would require a general multidimensional non-direct-product DVR scheme. Recently, Dawes and Carrington presented a practical scheme to implement general non-direct-product multidimensional DVRs [R. Dawes and T. Carrington, Jr., J. Chem. Phys. 121, 726 (2004)]. The present work utilizes their scheme in the MCTDH/CDVR approach. The accuracy is tested using the photodissociation of NOCl as example. The results show that the CDVR scheme based on multidimensional time-dependent DVRs allows for an accurate evaluation of the potential in MCTDH calculations with multidimensional single-particle functions.

Harrevelt, Rob van; Manthe, Uwe [Theoretische Chemie, Universitaet Bielefeld, Postfach 100131, D-33501 Bielefeld (Germany); Theoretische Chemie, Technische Universitaet Muenchen, Lichtenbergstrasse 4, D-85747 Garching (Germany)

2005-08-08T23:59:59.000Z

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.


61

Corrosion of valve metals  

DOE Green Energy (OSTI)

A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized. (FS)

Draley, J.E.

1976-01-01T23:59:59.000Z

62

Valve for abrasive material  

DOE Patents (OSTI)

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

Gardner, Harold S. (Turtle Creek, PA)

1982-01-01T23:59:59.000Z

63

A rotary-airlock valve resists abrasive mixtures  

SciTech Connect

Hill and Griffith (H and G, Cincinnati, Ohio) is a leading supplier of custom-blended additives to founderies. Thousands of tons of clay and carbon blends such as bentonite, gilsonite and pulverized coal, pass through the company's rotary-airlock feeding system each month. H and G's original rotary valves had cylinders lined with chrome, and closed-end rotors with tips made from nickel-chromium alloys. These valves remained in service for a maximum of only three months each. During that time, the abrasive mixtures passing through the valves virtually eroded them, increasing tolerances and causing significant air leakage. The leaks caused the pneumatic line to plug up, reducing the velocity of the line below the minimum level needed to carry any material. To overcome the leakage, a second blower was added to the system. This unit supplied an additional 40 brake hp to the pneumatic-conveying line. With constant maintenance of the valve and the continuous operation of both blowers, H and G was able to extend the valve's life by nine months. After 20 years of trying valves with various configuration, H and G installed a Smoot Type 6 rotary-airlock valve in September of 1985. The new valve's internals were made from abrasion-resistant grades of NiHard and Stellite. This combination of alloys prolonged the active life of the valve by improving its abrasion resistance. During its first year, the Smoot valve did not break down, leak air or require use of the secondary blower. After its first year of service no wear was found on the valve's internal surfaces. Another mechanical analysis was performed in 1991, after five additional years of valve operation. The valve, which had now handled more than 250,000 tons of product, showed minimal wear. H and G's capital costs had been reduced from 25[cents]/ton to 3[cents]/ton by the new valve.

Not Available

1993-03-01T23:59:59.000Z

64

Nuclear Data in Oklo and Time-Variability of Fundamental Coupling Constants  

E-Print Network (OSTI)

We re-examined Shlyakhter's analysis of the Sm data in Oklo. With a special care of minimizing contamination due to the inflow of the isotope after the end of the reactor activity, we confirmed that his result on the time-variability of the fine-structure constant, $|\\dot{\\alpha}/\\alpha |\\lsim 10^{-17}{\\rm y}^{-1}$, was basically correct. In addition to this upper bound, however, we obtained another result that indicates a different value of $\\alpha$ 2 billion years ago. We add comments on the recent result from QSO's.

Yasunori Fujii; Akira Iwamoto; Tokio Fukahori; Toshihiko Ohnuki; Masayuki Nakagawa; Hiroshi Hidaka; Yasuji Oura; Peter Moller

2002-05-19T23:59:59.000Z

65

Trend Change Detection in NDVI Time Series: Effects of Inter-Annual Variability and Methodology  

E-Print Network (OSTI)

Abstract: Changing trends in ecosystem productivity can be quantified using satellite observations of Normalized Difference Vegetation Index (NDVI). However, the estimation of trends from NDVI time series differs substantially depending on analyzed satellite dataset, the corresponding spatiotemporal resolution, and the applied statistical method. Here we compare the performance of a wide range of trend estimation methods and demonstrate that performance decreases with increasing inter-annual variability in the NDVI time series. Trend slope estimates based on annual aggregated time series or based on a seasonal-trend model show better performances than methods that remove the seasonal cycle of the time series. A breakpoint detection analysis reveals that an overestimation of breakpoints in NDVI trends can result in wrong or even opposite trend estimates. Based on our results, we give practical recommendations for the application of trend methods on long-term NDVI time series. Particularly, we apply and compare different methods on NDVI time series in Alaska, where both greening and browning trends have been previously observed. Here, the multi-method uncertainty of NDVI trendsRemote Sens. 2013, 5 2114

Matthias Forkel; Nuno Carvalhais; Jan Verbesselt; Miguel D. Mahecha; Christopher S. R. Neigh; Markus Reichstein

2013-01-01T23:59:59.000Z

66

Improve safety with pilot operated relief valves  

Science Conference Proceedings (OSTI)

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

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

1996-10-01T23:59:59.000Z

67

ANALYSIS OF CHECK VALVE DISC MOTION DURING A FLOW TRANSIENT  

SciTech Connect

An analysis of the dynamics of a check valve disc under the influence of a flow transient is presented. The impact velocities of the disc and the pressure surge resulting from extinguishing a fluid velocity are predicted. This analysis develops the equations of motion of a simple swing disc check valve from Newton's Second Law. Modifications of the analysis necessary for application to other types of valves are described. The developed equations are progiammed for the Philco-2000 digital computer in FORTRAN as the SLAM Code. The Code input consists of the characteristics of the valve and the flow transient. The output of the code includes the dynamics of the valve disc as a function of time and the pressure surge induced by valve closure. (H.G.G.)

Fuls, G.M.

1962-12-01T23:59:59.000Z

68

Dissolution Actuated Valve Sampler  

Engineers at the Savannah River National Laboratory (SRNL) have invented a new device for retrieving liquid samples. The dissolution actuated valve sampler was developed to obtain pristine samples while operating without the assistance of a mast or ...

69

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

70

Low-Frequency Variability in the Northern Hemisphere Winter: Geographical Distribution, Structure and Time-Scale Dependence  

Science Conference Proceedings (OSTI)

Low-frequency variability in wintertime 500 mb height is examined, with emphasis on its structure, geographical distribution, and frequency dependence. A 39-year record of 500 mb geopotential height fields from the NMC analyses is time filtered ...

Yochanan Kushnir; John M. Wallace

1989-10-01T23:59:59.000Z

71

Rainfall Variability at Decadal and Longer Time Scales: Signal or Noise?  

Science Conference Proceedings (OSTI)

Rainfall variability occurs over a wide range of temporal scales. Knowledge and understanding of such variability can lead to improved risk management practices in agricultural and other industries. Analyses of temporal patterns in 100 yr of ...

Holger Meinke; Peter deVoil; Graeme L. Hammer; Scott Power; Robert Allan; Roger C. Stone; Chris Folland; Andries Potgieter

2005-01-01T23:59:59.000Z

72

Analysis Methods for Characterizing Salinity Variability from Multivariate Time Series Applied to the Apalachicola Bay Estuary  

Science Conference Proceedings (OSTI)

Statistical analysis methods are developed to quantify the impacts of multiple forcing variables on the hydrographic variability within an estuary instrumented with an enduring observational system. The methods are applied to characterize the ...

Steven L. Morey; Dmitry S. Dukhovskoy

2012-04-01T23:59:59.000Z

73

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

74

REACTOR SYSTEM AND CONTROL VALVE  

DOE Patents (OSTI)

Valves have been developed for controlling the flow of gaseous fluid through a passage or conduit. The valves have particular application in the cooling systems of gas; cooled reactors. (R.J.S.)

Fortescue, P.; Rickard, C.; Rose, D.

1963-01-01T23:59:59.000Z

75

Hydrogen gas relief valve  

SciTech Connect

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

Whittlesey, Curtis C. (Birmingham, MI)

1985-01-01T23:59:59.000Z

76

Improved bellows sealed plug valve  

DOE Patents (OSTI)

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

Dukas, S.J. Jr.

1989-10-29T23:59:59.000Z

77

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, J.J.

1990-12-31T23:59:59.000Z

78

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

Science Conference Proceedings (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

79

Valve for cryogenic service  

DOE Patents (OSTI)

This patent relates to a valve for use with a liquefied gas at cryogenic temperatures in which a pair of joined knife edges are bellows controlled to contact an indium alloy seat in an annular slot when flow is to be stopped. The sealing alloy may be renewed by heating in situ. (auth)

Worwetz, H.A.

1975-09-02T23:59:59.000Z

80

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

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

Analysis of Short SpaceTime-Scale Variability of Oceanic Rain Using TOPEX/Jason  

Science Conference Proceedings (OSTI)

Information on the spatial and temporal variability of rain rate is important not only for meteorology and hydrology but also for the design of remote sensing and in situ measuring or of millimeter wave communication systems. The Ocean Topography ...

J. Tournadre; S. Bhandari

2009-01-01T23:59:59.000Z

82

Plenary lecture 3: variable structure control and time-delay systems: a survey  

Science Conference Proceedings (OSTI)

It is well known that the variable structure control is now recognized as one of the powerful robust tools for solving control problems of uncertain linear and nonlinear dynamical systems subject to parameter perturbations, unmodeled dynamics, external ...

Elbrous M. Jafarov

2010-05-01T23:59:59.000Z

83

Bayesian Rainfall Variability Analysis in West Africa along Cross Sections in SpaceTime Grid Boxes  

Science Conference Proceedings (OSTI)

This paper proposes an approach for analyzing rainfall variability over West Africa during the 195090 period. Three grid boxes, corresponding to three selected areas over West Africa, have been constructed. For each candidate area the set of ...

Dominique Tapsoba; Mario Hach; Luc Perreault; Bernard Bobe

2004-03-01T23:59:59.000Z

84

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

Science Conference Proceedings (OSTI)

Spatial and temporal patterns of variability in spring onset are identified across western North America using a spring index (SI) model based on weather station minimum and maximum temperatures (Tmin and Tmax, respectively). Principal component ...

Toby R. Ault; Alison K. Macalady; Gregory T. Pederson; Julio L. Betancourt; Mark D. Schwartz

2011-08-01T23:59:59.000Z

85

Valve selection handbook. Third edition  

Science Conference Proceedings (OSTI)

This book covers the fundamentals of value construction and application, and analyzes the different hazards and requirements of all types of industrial fluid flow situations. This book expands the coverage of pressure relief valves and rupture discs. It includes a new section on damping valve chatter, which is a serious problem in installations such as atomic power plants where valve chatter could have catastrophic consequences to the safety of the plant. There is also new information on performance of spring-loaded pressure relief valves and a closer examination of valve selection with respect to rupture discs and explosion venting.

Zappe, R.W. (ICI Australia Operations Pty. Ltd. (AU))

1991-01-01T23:59:59.000Z

86

Dual valve well pump installation  

SciTech Connect

A reciprocating electric motor-pump assembly for lifting well fluid on downstroke of the motor pump assembly, the pump including a barrel below the motor having dual combined inlet and outlet valve means at the lower end thereof, the pump piston moving in the barrel having annular grooves therearound to prevent differential pressure sticking, the electric cable supplying the electric motor being tubular to vent the pump and prevent vacuum or gas lock, there being a packer about the valve barrel separating the outlet valve means thereabove from the inlet valve means therebelow and a packer above the motor about a production tubing including an upper standing valve.

Holm, D. R.

1985-10-22T23:59:59.000Z

87

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

88

Throttled Valve Cavitation and Erosion  

E-Print Network (OSTI)

The submitted manuscipt has been authored by a contmrctor of the US. Government under contract No. DE-AC05-840R21400. Accordingly, the U. S. Government retains a nonexclusive royalty-free license to publish or reproduce the published form of the contribution, or aflow others to do so, for US. Government pupose & 1. Background In November of 1988, Brunswick plant maintenance personnel discovered significant localized erosion of the valve body of a Unit I Residual Heat Removal (RHR) valve, 1-El 1-F017B (the maintenance was being performed to repair the valve stem and back seat). 1 The F017B valv'e is a 20-inch Rockwell angle globe valve that has been historically used to throttle RHR flow. Excessive throttling of the valve had resulted in cavitation-induced erosion damage to areas immediately downstream of the seat. Subsequent investigation indicated that erosion of valve bodies was a generic concern for the other RHR valves used in the same service (FO17A on Unit I and F017A and F017B on Unit 2). Brunswick personnel expanded the investigation to include another set of RHR valves that had also been used in throttling service. The F024A and F024B valves (from both Units), which are used for Suppression Pool Cooling, were also found to have been damaged by

Don Casada; Don Casada

1991-01-01T23:59:59.000Z

89

Micro-valve pump light valve display  

DOE Patents (OSTI)

In this invention, 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 substrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

Lee, Yee-Chun

1991-01-15T23:59:59.000Z

90

Micro-valve pump light valve display  

DOE Patents (OSTI)

In this invention, 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 substrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

Lee, Yee-Chun.

1991-01-15T23:59:59.000Z

91

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

92

CMOS Open Defect Detection Based on Supply Current in Time-Variable Electric Field and Supply Voltage Application  

Science Conference Proceedings (OSTI)

In this paper, a new test method is proposed for detecting open defects in CMOS ICs. The method is based on supply current of ICs generated by applying time-variable supply voltage and electric field from the outside of the ICs. The feasibility of the ...

Masaki Hashizume; Masahiro Ichimiya; Hiroyuki Yotsuyanagi; Takeomi Tamesada

2001-11-01T23:59:59.000Z

93

Signal-dependent variable-resolution clockless A/D conversion with application to continuous-time digital signal processing  

Science Conference Proceedings (OSTI)

A variable-resolution (VR) quantizer with input-activity-dependent adjustable resolution is presented. Several potential schemes are discussed; the favored scheme achieves adjustable resolution by level skipping according to the speed of the input. The ... Keywords: analog-to-digital converter (ADC), continuous-time digital signal processing (CT DSP), level-crossing sampling, quantization

Mariya Kurchuk; Yannis Tsividis

2010-05-01T23:59:59.000Z

94

On Structure and History of Space-time with Variable Speed of Light  

E-Print Network (OSTI)

We apply the variable speed of light into general relativity in order to solve the problems we met in the standard cosmology. We're surprised to find that, the results from the general relativity in cosmology are exactly the same as those we got from Newtonian dynamics. The relation between the Newtonian dynamics and the relativistic dynamics can be demonstrated with the variable speed of light. With this approach, some problems in the standard cosmology such as the flatness problem and the horizon problem doesn't arise any more. All the cosmological results and the physical results are reasonable and natural. There are no any difficulties in the standard cosmology.

Guoyou Huang

2004-10-15T23:59:59.000Z

95

Time and Space Variability of Rainfall in Central-East Argentina  

Science Conference Proceedings (OSTI)

Climatic variability of monthly rainfall data over a period of 30 yr is analyzed. Twenty-three precipitation locations of the central pampa region of Argentina were used. They are spread over the transition zone between wet and dry pampa. The ...

Carlos M. Krepper; Beatriz V. Scian; Jorge O. Pierini

1989-01-01T23:59:59.000Z

96

The Hydroclimatology of Kuwait: Explaining the Variability of Rainfall at Seasonal and Interannual Time Scales  

Science Conference Proceedings (OSTI)

This paper presents an analysis of the spatial, seasonal, and interannual variabilities of Kuwaiti rainfall. Based on an analysis of rain gauge, as well as satellite, datasets, it is estimated that about 110190 mm of rainfall occurs annually in ...

Marc P. Marcella; Elfatih A. B. Eltahir

2008-10-01T23:59:59.000Z

97

Fast-acting valve and uses thereof  

SciTech Connect

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

98

Performance Characteristics of an Isothermal Freeze Valve  

Science Conference Proceedings (OSTI)

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

Hailey, A.E.

2001-08-22T23:59:59.000Z

99

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

DOE Green Energy (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

100

Semi-active compressor valve  

SciTech Connect

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

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

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

102

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.

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

1983-01-01T23:59:59.000Z

103

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

104

Valve stem and packing assembly  

SciTech Connect

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

105

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

106

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, J.J.

1990-01-01T23:59:59.000Z

107

DISCHARGE VALVE FOR GRANULAR MATERIAL  

DOE Patents (OSTI)

A gravity-red dispenser or valve is designed for discharging the fueled spherical elements used in a pebble bed reactor. The dispenser consists of an axially movable tube terminating under a hood having side walls with openings. When the tube is moved so that its top edge is above the tops of the side openings the elements will not flow. As the tube is moved downwardly, the elements flow into the hood through the side openings and over the top edge into the tube at an increasing rate as the tube is lowered further. The tube is spaced at all times from the hood and side walls a distance greater than the diameter of the largest element to prevent damaging of the elements when the dispenser is closed to flow. (AEC)

Stoughton, L.D.; Robinson, S.T.

1962-05-15T23:59:59.000Z

108

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

109

Model-based estimation of time-varying parameters and state variables in aerobic bioprocesses  

Science Conference Proceedings (OSTI)

Keywords: adaptive observer, aerobic bioprocess, biomass concentration, biomass growth rate, model-based estimation, observer stability, oxygen comsumption, time-varying parameters, yield coefficient

V. Lubenova

2000-08-01T23:59:59.000Z

110

Time Scales and Variability of Area-Averaged Tropical Oceanic Rainfall  

Science Conference Proceedings (OSTI)

A statistical analysis of time series of area-averaged rainfall over the oceans has been conducted around the diurnal time scale. The results of our analysis can be applied directly to the problem of establishing the magnitude of expected errors ...

Kyung-Sup Shin; Gerald R. North; Yoo-Shin Ahn; Phillip A. Arkin

1990-07-01T23:59:59.000Z

111

Large-Eddy Simulation of Air Parcels in Stratocumulus Clouds: Time Scales and Spatial Variability  

Science Conference Proceedings (OSTI)

Large ensembles of air parcel trajectories driven by the (large-eddy simulation) LES-generated velocity fields from simulations of stratocumulus clouds were analyzed, focusing on statistics of air parcel in-cloud time scales, as well as their ...

Yefim L. Kogan

2006-03-01T23:59:59.000Z

112

A new battery energy storage system control method based on SOC and variable filter time constant  

Science Conference Proceedings (OSTI)

Because of large fluctuations and strong randomness of active power generated by renewable energy resources, taking into account the constraints such as battery life cycle, a new battery energy storage system control method based on real-time state-of-charge ...

Li Guo; Ye Zhang; Cheng Shan Wang

2012-01-01T23:59:59.000Z

113

Generation of continuous variable squeezing and entanglement of trapped ions in time-varying potentials  

Science Conference Proceedings (OSTI)

We investigate the generation of squeezing and entanglement for the motional degrees of freedom of ions in linear traps, confined by time-varying and oscillating potentials, comprised of a DC and an AC component. We show that high degrees of squeezing ... Keywords: 03.67.Bg, 05.45.Xt, 37.10.Vz, 42.50.Dv, Control, Entanglement, Ion traps

Alessio Serafini; Alex Retzker; Martin B. Plenio

2009-12-01T23:59:59.000Z

114

Time dependent simulations of multiwavelength variability of the blazar Mrk 421 with a Monte Carlo multi-zone code  

E-Print Network (OSTI)

(abridged) We present a new time-dependent multi-zone radiative transfer code and its application to study the SSC emission of Mrk 421. The code couples Fokker-Planck and Monte Carlo methods, in a 2D geometry. For the first time all the light travel time effects (LCTE) are fully considered, along with a proper treatment of Compton cooling, which depends on them. We study a set of simple scenarios where the variability is produced by injection of relativistic electrons as a `shock front' crosses the emission region. We consider emission from two components, with the second one either being pre-existing and co-spatial and participating in the evolution of the active region, or spatially separated and independent, only diluting the observed variability. Temporal and spectral results of the simulation are compared to the multiwavelength observations of Mrk 421 in March 2001. We find parameters that can adequately fit the observed SEDs and multiwavelength light curves and correlations. There remain however a few o...

Chen, Xuhui; Liang, Edison; Boettcher, Markus

2011-01-01T23:59:59.000Z

115

Dark energy model with variable $q$ and $?$ in LRS Bianchi-II space-time  

E-Print Network (OSTI)

The present study deals with spatial homogeneous and anisotropic locally rotationally symmetric (LRS) Bianchi-II dark energy model in general relativity. The Einstein's field equations have been solved exactly by taking into account the proportionality relation between one of the components of shear scalar $(\\sigma^{1}_{1})$ and expansion scalar $(\\vartheta)$, which, for some suitable choices of problem parameters, yields time dependent equation of state (EoS) and deceleration parameter (DP), representing a model which generates a transition of universe from early decelerating phase to present accelerating phase. The physical and geometrical behavior of universe have been discussed in detail.

Bijan Saha; Anil Kumar Yadav

2011-10-21T23:59:59.000Z

116

VAST - a real-time pipeline for detecting radio transients and variables on the Australian SKA Pathfinder (ASKAP) telescope  

E-Print Network (OSTI)

The Australian SKA Pathfinder (ASKAP) is a next generation radio telescope currently under construction in Western Australia. The fast survey speed and wide field of view make it an ideal instrument for blind transients searches. The ASKAP Variable and Slow Transients (VAST) survey is a one of the major science programs planned for ASKAP. The scientific goals of VAST include the detection and characterisation of a wide range of transient and variable phenomena, from gamma-ray burst afterglows to extreme scattering events, on timescales of 5 seconds or longer. We describe the data and processing challenges involved in running the VAST real-time transient detection pipeline. ASKAP will produce 2.5 GB of visibility data per second, transformed into one 8GB image cube every 5 seconds. Each cube will contain approximately twenty 100 megapixel images with 100s of radio sources detected in each epoch. The VAST pipeline will measure and monitor all of these sources, detect variables and transients and generate alerts...

Banyer, Jay

2012-01-01T23:59:59.000Z

117

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

118

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

119

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

Science Conference Proceedings (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

120

Platelet thrombosis in cardiac-valve prostheses  

SciTech Connect

The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs.

Dewanjee, M.K.

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.


121

Retroactive Change in Unit Value There are times when a student has enrolled in a variable unit class for a unit value that needs to be either  

E-Print Network (OSTI)

Retroactive Change in Unit Value There are times when a student has enrolled in a variable unit class for a unit value that needs to be either increased or decreased retroactively. For stipulated reasons that are documented, a student may petition to retroactively change the unit value in a variable

de Lijser, Peter

122

Noninvasive valve monitor using alternating electromagnetic field  

SciTech Connect

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

123

Identifying Signatures of Natural Climate Variability in Time Series of Global-Mean Surface Temperature: Methodology and Insights  

Science Conference Proceedings (OSTI)

Global-mean surface temperature is affected by both natural variability and anthropogenic forcing. This study is concerned with identifying and removing from global-mean temperatures the signatures of natural climate variability over the period ...

David W. J. Thompson; John M. Wallace; Phil D. Jones; John J. Kennedy

2009-11-01T23:59:59.000Z

124

Development of a variable-temperature ion mobility/ time-of-flight mass spectrometer for separation of electronic isomers  

E-Print Network (OSTI)

The construction of a liquid nitrogen-cooled ion mobility spectrometer coupled with time-of-flight mass spectrometry was implemented to demonstrate the ability to discriminate between electronic isomers. Ion mobility allows for the separation of ions based on differing cross-sections-to-charge ratio. This allows for the possible discrimination of species with same mass if the ions differ by cross-section. Time-offlight mass spectrometry was added to mass identify the separated peak for proper identification. A liquid nitrogen-cooled mobility cell was employed for a two-fold purpose. First, the low temperatures increase the peak resolution to aid in resolving the separated ions. This is necessary when isomers may have similar cross-sections. Second, low temperature shortens the mean free path and decreases the neutral buffer gas speeds allowing for more interactions between the ions and the drift gas. Kr2+ study was performed to verify instrument performance. The variable-temperature ion mobility spectrometer was utilized to separate the distonic and conventional ion forms of CH3OH, CH3F, and CH3NH2 and to discriminate between the keto and enol forms of the acetone radical cation. Density functional theory and ab initio calculations were employed to aid in proper identification of separating isomers. Monte Carlo integration tools were also developed to predict ion cross-section and resolution within a buffer gas.

Verbeck, Guido Fridolin

2006-05-01T23:59:59.000Z

125

Lost-motion valve actuator  

SciTech Connect

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

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

1987-04-07T23:59:59.000Z

126

Variable-response model of electricity demand by time of day: Results of a Wisconsin pricing experiment: Final report  

Science Conference Proceedings (OSTI)

Observationally alike households may differ in demand parameters and thus in economic quantities that are functions of those parameters. We have proposed a methodology for dealing with this variation. Estimation of both translog and CES versions of the model with data from the Wisconsin Electricity Pricing Experiment revealed considerable variation among households in time-of-day electricity consumption demand parameters for both summer and winter seasons and for several different definitions of the peak period. Observed household characteristics explained only a small share of total household differences, but permanent household differences dominated month-to-month variation in either expenditure shares or log consumption ratios in most cases. Permanent differences among households are important relative to total variation, including transitory month-to-month variation. We calculated various economic variables from the demand parameters, including the partial elasticity of substitution, compensated and uncompensated elasticities, and a measure of electricity expenditure under peak load pricing required to maintain the utility level under flat rate pricing relative to the flat rate expenditure. Because these are nonlinear functions of the household demand parameters, the mean parameter value over households with different demand parameters may be substantially different from the value of the function at mean values, under the representative household paradigm. For time-of-day electricity demand, variation among households is significant but small relative to mean parameter values. Therefore, controlling for the effect of household variation makes little difference in these mean calculations, but it does imply substantial variation among households in the welfare implications (and elasticities of response) of the introduction of time-of-day pricing. 25 refs., 12 tabs.

Lillard, L.

1987-06-01T23:59:59.000Z

127

Valve for controlling flow of cryogenic fluid  

DOE Patents (OSTI)

A valve is provided for accurately controlling the flow of cryogenic fluids such as liquid nitrogen. The valve comprises a combination of disc and needle valves affixed to a valve stem in such a manner that the disc and needle are free to rotate about the stem, but are constrained in lateral and vertical movements. This arrangement provides accurate and precise fluid flow control and positive fluid isolation.

Knapp, P.A.

1995-12-31T23:59:59.000Z

128

Microfluidic Polymer Valves - Energy Innovation Portal  

No electrical power is dissipated into the fluid during valve operation. The microvalve dielectric strength is comparable to glass.

129

Experiences and Attributes of Successful Valve Teams  

Science Conference Proceedings (OSTI)

Recently, a number of utilities have found that an effective approach to improve valve performance and reliability is to develop specialized cross-disciplinary teams that have the responsibility for a specific valve or valve types throughout the plant or utility. This report describes the composition, size, and functions of the different types of valve teams studied and provides a myriad of success stories and lessons learned regarding their employment throughout the nuclear power industry.

2000-12-20T23:59:59.000Z

130

TWO-WAY FREEZE VALVE  

DOE Patents (OSTI)

A valve for closing off the flow of radioactive and corrosive gases and liquids or mixtures thereof and forming a leak tight barrier is described. This valve has no mechanical moving parts which would require design to close tolerances and retention of the usual seal tighthess. Instead, there is provided a cavity in which a fusible metal is contained. Heating and cooling are provided to exercise control over the state of the metal. Baffle chambers are utilized to separate the molten fusible metal from the gas or liquid which is being passed through and return the molten metal to its cavity.

Lantz, K.D.; Clark, P.M.

1960-01-01T23:59:59.000Z

131

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

132

Valve test program: response to TMI  

Science Conference Proceedings (OSTI)

The Electric Power Research Institute (EPRI) pressurized-water reactor (PWR) safety and relief valve test program was speedily organized to assess valve operability after a pressurizer relief valve malfunctioned at Three Mile Island (TMI). Comprehensive full-scale testing at several facilities validated the basic designs in use today. 2 figures.

Lihach, N.; Bilanin, W.; Carey, J.

1983-05-01T23:59:59.000Z

133

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

134

THE VALVE-ACTUATED PULSE COLUMN DESIGN AND OPERATION  

SciTech Connect

A countercurrent extraction column is described which employs timed solenoid valves and pressurized feeds to provide a pulsing action to disperse the phases. The steps in the pulsing cycle are independent and thus provide greater separation of the operating variables than is possible with conventional pulse columns. The column described is particularly useful as a resesrch tool for the study of extraction mechanism although a larger installation operating on the same principles should be quite workable. The 4-stage-cycle or mixersettler type column operation has an inherent advantage in that the rapid coalescence and redispersion of phases are believed to lead to greater extraction than simple movement of a dispersed phase through a continuous medium. In addition, the sharp pulse provided should produce greater turbulence than the more conventional pulsing arrangement. Some results of operation on the extraction and stripping of uranyl nitrate using tributyl phosphate as a solvent are included. These data correspond to Metal Recovery and Erex type systems. (auth)

Burger, L.L.; Clark, L.H.

1951-12-01T23:59:59.000Z

135

Hydraulic servo control spool valve  

DOE Patents (OSTI)

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

Miller, Donald M. (Sunnyside, WA)

1983-01-01T23:59:59.000Z

136

Valve assembly for inflatable packer  

Science Conference Proceedings (OSTI)

This patent describes a valve assembly for controlling the flow of fluid from within casing into a bladder element of an inflatable packer for use in a wellbore. The bladder element has bladder port means. The valve assembly is mountable within a single cavity in a body member in the wall of casing or a casing coupling. The body member has casing port means communicating with the cavity for communicating casing fluid to the bladder port means so that the casing fluid can flow through the bladder port means to inflate the bladder element and the body member having overpressure port means communicating with the cavity for communicating part of the fluid flowing into the bladder element back to the cavity and to the valve assembly. The valve assembly comprises: control piston means movably mounted within the cavity, restraint means for insuring that the control piston means initially moves only when the pressure of the casing fluid reaches a predetermined level, and closing piston means movably mounted within the cavity and responsive to the pressure of the fluid in the bladder element, and the control piston means and the closing piston movable about stem means disposed in the cavity.

Stringfellow, W.D.

1987-12-08T23:59:59.000Z

137

Valve Application, Maintenance, and Repair Guide  

Science Conference Proceedings (OSTI)

The Valve Application, Maintenance, and Repair Guide is a two-volume series that provides a generic overview of valve application, selection, maintenance, and repair. Volume 1 of the series is a comprehensive reference on the application and use of valves that provides guidance on the selection of specific types of valves on the basis of functional and system requirements. This document is based on an earlier EPRI document (NP-6516, Guide for the Application and Use of Valves in Power Plant Systems). Ext...

1999-05-07T23:59:59.000Z

138

Change-over valve for air suspension  

Science Conference Proceedings (OSTI)

A change-over valve is described for an air suspension interposed between a main air chamber formed to surround a shock absorber provided with a piston rod and an auxiliary air chamber, comprising: a valve base having a first hole through which the piston rod extends and a second hole into which a valve body is inserted; the valve body disposed in the second hole; a holder disposed in the second hole; and means removably fixed to the piston rod extending through the first hole to connect the piston rod with the valve base while preventing the holder from falling out.

Buma, S.

1987-04-28T23:59:59.000Z

139

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

140

A LARGE BAKEABLE VACUUM VALVE  

SciTech Connect

The development and design of a large bakeable valve based on a unique seat arrangement and a novel motion seal are described. The seat sealing is accomplished through the use of high pressure fluid actuation of an annular pinch gasket. Experimental data on seat closure performance, and the specific design features to achieve successful closures, are presented. The bakeable motion seal utilizes a stainless steel bellows sleeving over an inner concentric actuating shaft. This shaft is bent at 90 deg to the axis of rotation and is free to rotate relative to the bellows. There is no apparent size limitation to this type of actuation. The design of a 10-inch gate valve utilizing these principles is described. (auth)

Batzer, T.H.

1959-08-01T23:59:59.000Z

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.


141

Enhancement of spin-dependent scattering and improvement of microstructure in spin valves by delayed deposition  

Science Conference Proceedings (OSTI)

Si/Ta/Co/Cu/CoFeMn (or NiO) spin valves were prepared by a delayed sputtering procedure, in which depositions of Ta and followed layers were intervened by 1 h. The spin valves are found to have better coherent growth with stronger (111) preferred orientations in Co and Cu layers, compared with the traditional continuous method. At the same time, the giant magnetoresistance ratio and spin-dependent scattering are enhanced by a factor of 20%-30%. These results indicate that the coherent growth and the (111) preferred orientation can enhance the spin-dependent scattering of spin valves.

Yang, D.Z.; Wang, L.; Yang, X.J.; Zhou, S.M.; Wu, X.S.; Du, J.; Hu, A.; Zhang, X.X. [Surface Physics Laboratory (State Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433 (China) and Department of Physics, Southeast University, Nanjing 210096 (China); Surface Physics Laboratory (State Key Laboratory) and Department of Physics, Fudan University, Shanghai 200433 (China); National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Department of Physics, Hong Kong University of Science and Technology, Kowloon, Hong Kong (China)

2005-06-20T23:59:59.000Z

142

International Steam Turbine Valve Metallurgy Guide  

Science Conference Proceedings (OSTI)

This report reviews the state of the art in materials usage for steam turbine valves manufactured and used in Europe and looks at materials options for the higher-temperature applications now being considered for advanced high-efficiency power plants. The emphasis is on valves for extreme service conditions (high temperatures, pressures, and flow rates), of which bypass valves represent a good example. Some consideration is also given to degradation and failure mechanisms. In focusing on practices outsid...

2011-09-27T23:59:59.000Z

143

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

144

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

145

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

146

IMPROVEMENTS IN OR RELATING TO VALVED DUCTING  

SciTech Connect

A coaxial valved ducting is designed for fluid flow to and from a heat exchanger. The ducting comprises an inner pipe for flow of hot fluid, an outer pipe providing an annular passage for the countercurrent flow of cool fluid, a butterfly valve in the inner pipe, peripherally spaced longitudinal ribs joining the two pipes in the region of the valve, an extension of the outer pipe, and a butterfly or poppet valve associated with the extension. the inner pipe communicates with the heat exchanger by means of an extension through the outer pipe wall. (D.L.C.)

Blackburn, G.; Long, E.

1962-05-30T23:59:59.000Z

147

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, R.W.; Pawlak, D.A.; Ramey, A.J.

1982-06-10T23:59:59.000Z

148

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

149

Method and apparatus for monitoring motor operated valve motor ...  

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 ...

150

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.

McCray, John A. (Idaho Falls, ID)

1999-01-01T23:59:59.000Z

151

Vertical pump with free floating check valve  

DOE Patents (OSTI)

A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

Lindsay, Malcolm (O' Hara Township, Allegheny County, PA)

1980-01-01T23:59:59.000Z

152

Beyond long memory in heart rate variability: An approach based on fractionally integrated autoregressive moving average time series models with conditional heteroscedasticity  

Science Conference Proceedings (OSTI)

Heart Rate Variability (HRV) series exhibit long memory and time-varying conditional variance. This work considers the Fractionally Integrated AutoRegressive Moving Average (ARFIMA) models with Generalized AutoRegressive Conditional Heteroscedastic (GARCH) errors. ARFIMA-GARCH models may be used to capture and remove long memory and estimate the conditional volatility in 24 h HRV recordings. The ARFIMA-GARCH approach is applied to fifteen long term HRV series available at Physionet

2013-01-01T23:59:59.000Z

153

Hindcasting Ocean Climate Variability Using Time-Dependent Surface Data to Drive a Model: An Idealized Study  

Science Conference Proceedings (OSTI)

This paper investigates the hindcasting of interdecadal climate events using an ocean circulation model driven by different combinations of time-varying surface flux, sea surface temperature (SST), and sea surface salinity (SSS) data. Data are ...

Richard J. Greatbatch; Guoqing Li; Sheng Zhang

1995-11-01T23:59:59.000Z

154

Valve for controlling solids flow  

DOE Patents (OSTI)

A valve for controlling the flow of solids comprises a vessel having an overflow point, an inlet line for discharging solids into the vessel positioned within the vessel such that the inlet line's discharge point is lower than the vessel's overflow point, and apparatus for introducing a fluidizing fluid into the vessel. The fluidizing fluid fluidizes the solids within the vessel so that they overflow at the vessel's overflow point. For the removal of nuclear waste product the vessel may be placed within a sealed container having a bottom connected transport line for transporting the solids to storage or other sites. The rate of solids flow is controlled by the flow rate of the fluidizing fluid and by V-notch weirs of different sizes spaced about the top of the vessel.

Staiger, M. Daniel (Idaho Falls, ID)

1985-01-01T23:59:59.000Z

155

Time-Frequency Analysis of GALLEX and GNO Solar Neutrino Data: Evidence Suggestive of Asymmetric and Variable Nuclear Burning  

E-Print Network (OSTI)

Time-frequency analysis of data from the GALLEX and GNO solar neutrino experiments shows that some features in power-spectrum analyses of those datasets are due to aliasing. We normalize data for each of the four experiments in the GALLEX series, concatenate the resulting normalized data, and then form time-frequency displays. We also form time-frequency displays of the two principal modulations found in the data, at 11.87 yr-1 and at 13.63 yr-1, and of the datasets formed by subtracting these modulations from the actual (normalized) data. The results suggest that the true modulation is that at 11.87 yr-1, consistent with the results of our earlier analysis of Homestake solar neutrino data. Comparison with helioseismology data indicates that modulation is occurring either in the radiative zone just below the tachocline, presumably by the RSFP (resonant spin-flavor precession) process, or in the core, presumably due to inhomogeneities and fluctuations in the nuclear-burning process.

P. A. Sturrock

2008-02-22T23:59:59.000Z

156

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

157

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

158

Engineering Technical Training Modules - Throttle Valves 1.0  

Science Conference Proceedings (OSTI)

The purpose of this training module is to provide an understanding of specifying throttle valves in a nuclear power plant. The module provides the student with an understanding of the different types of throttle valves, how to select a throttle valve, understand the flow characteristics of different throttle valves, and understanding negative characteristics that can occur when the wrong valve is chosen for different applications. Prior to using this module, the student should understand the fundamental...

2011-06-29T23:59:59.000Z

159

EPRI-Marshall Electric Motor-Operated Valve (Block Valve) Interim Test Data Report  

Science Conference Proceedings (OSTI)

At the request of participating PWR utilities, an overall program was developed at EPRI for the full-scale testing of a representative set of primary-system safety and relief valves. The program was to assist the PWR utilities in meeting NUREG 0737, Item II.D.1.A requirements. Although not a formal part of the program, some block valve operability data were also obtained during the relief valve testing performed at Marshall Steam Station in Terrell, North Carolina. A total of seven block valve designs we...

1982-07-01T23:59:59.000Z

160

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

Science Conference Proceedings (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

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

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

162

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

163

Install Removable Insulation on Valves and Fittings  

Science Conference Proceedings (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

164

Valve Application, Maintenance, and Repair Guide: In Situ State-of-the-Art Valve Welding Repair (Gate, Globe, & Check Valves), Volum e 2  

Science Conference Proceedings (OSTI)

The Valve Application, Maintenance and Repair Guide is a three volume series that provides a generic overview of valve application selection, maintenance, and repair. Volume 2 of this series is a comprehensive guide for in situ weld repair of gate, globe, and check valve components such as bodies, bonnets, discs, and seats. The information in this guide, though directed toward nuclear plant personnel, will assist all power plant engineers, planners, and maintenance personnel responsible for valve mainten...

1996-12-31T23:59:59.000Z

165

Diffusion bonding resistant valve development for sodium service  

SciTech Connect

Unanticipated functional failures occurred in valves undergoing containment integrity testing for liquid sodium service. The failures resulted from diffusion bonding of the Stellite 6B valve plug to the Type 316 stainless steel (SS) seat. As a result of these failures, a valve development program was undertaken. A modified valve incorporating a Tribaloy 800 plug showed significant improvement in resistance to diffusion bonding but still failed after long term exposure in a closed position. A second modified valve using Tribaloy 800 in both the valve plug and seat successfully resisted diffusion bonding failure. This paper reports the details of the testing and posttest valve examinations. The results of scanning electron microscopy, dispersive x-ray spectrometry, and metallography provide the characteristics of the valve failures. Limitations of the various valve designs are also discussed.

Crandall, D.L.; Low, J.O.; Chung, D.T.; Loop, R.B.

1984-04-16T23:59:59.000Z

166

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES  

DOE Green Energy (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

167

Subsea production test valve assembly  

SciTech Connect

In the subsea test assembly securable within a blowout preventer stack above a subterranean well and positionable between upper and lower portions of a tubular conduit in fluid communication with a production zone within the well, the test assembly is described including an upper subassembly carriable with the upper conduit portion, a lower subassembly carriable with the lower conduit portion, and valve means in the lower subassembly manipulatable between opened and closed positions to control fluid flow within the conduit. The improvement comprises: the upper subassembly including an upper housing and first rigid dog means fixedly secured to the upper housing; the lower subassembly including a lower housing and second rigid dog means fixedly secured to the lower housing; the first rigid dog means positionable between a latch position for latching the upper and lower subassemblies and an unlatch position for unlatching the upper and lower subassemblies upon rotational movement of the first dog means with respect to the second dog means; and lock means axially movable relative to the first and second dog means from a lock position for limiting rotational movement of the first dog means with respect to the second dog means to an unlock position for allowing the first dog means to rotate relative to the second dog means and unlatch the upper subassembly from the lower subassembly.

Yates, P.D.

1988-03-22T23:59:59.000Z

168

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

SciTech Connect

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

169

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  

DOE Green Energy (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

170

Performance Variability  

NLE Websites -- All DOE Office Websites (Extended Search)

Variability Variability of Highly Parallel Architectures William T.C. Kramer 1 and Clint Ryan 2 1 Department of Computing Sciences, University of California at Berkeley and the National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory 2 Department of Computing Sciences, University of California at Berkeley Abstract. The design and evaluation of high performance computers has concentrated on increasing computational speed for applications. This performance is often measured on a well configured dedicated sys- tem to show the best case. In the real environment, resources are not always dedicated to a single task, and systems run tasks that may influ- ence each other, so run times vary, sometimes to an unreasonably large extent. This paper explores the amount of variation seen across four large distributed memory systems in a systematic manner. It then

171

Design of a Thermally-Actuated Gas Lift Safety Valve  

E-Print Network (OSTI)

Gas-lifted oil wells are susceptible to failure through malfunction of gas lift valve assemblies (GLV). One failure mode occurs when the GLV check valve fails and product passes into the well annulus, potentially reaching ...

Gilbertson, Eric W.

172

Miniature Fluid Control Valve - Oak Ridge National Laboratory  

Summary: Technology Description A very small control valve that is used to control flow into and out of a finger prosthesis. The valve makes use of a spring loaded poppet

173

Exhaust gas bypass valve control for thermoelectric generator  

DOE Patents (OSTI)

A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter (Peter) Jacobus; Anderson, Todd Alan

2012-09-04T23:59:59.000Z

174

Worcester Solenoid Actuated Gas Operated MCO Isolation Valves  

SciTech Connect

These valves are 1 inch gas-operated full-port ball valves incorporating a solenoid and limit switches as Integral parts of the actuator that are used in different process streams within the CVDF hood. The valves fail closed (on loss of pressure or electrical) for MCO isolation to either reduce air in leakage or loss of He. All valves have coupling for transverse actuator mounting.

VAN KATWIJK, C.

2000-06-06T23:59:59.000Z

175

Worchester Solenoid Actuated Gas Operated MCO Isolation Valves  

Science Conference Proceedings (OSTI)

These valves are 1 inch gas-operated full-port ball valves incorporating a solenoid and limit switches as integral parts of the actuator that are used in process streams within the CWF hood. The valves fail closed (on loss of pressure or electrical) to prevent MCO vent drain to either reduce air In-leakage or loss of He. The valves have couplings for transverse actuator mounting.

MISKA, C.R.

2000-11-13T23:59:59.000Z

176

Worcester Solenoid Actuated Gas Operated MCO Isolation Valves  

Science Conference Proceedings (OSTI)

These valves are 1 inch gas-operated full-port ball valves incorporating a solenoid and limit switches as integral parts of the actuator that are used in different process streams within the CVDF hood. The valves fail closed (on loss of pressure or electrical) for MCO isolation to either reduce air leakage or loss of He. All valves have coupling for transverse actuator mounting.

MISKA, C.R.

2000-11-13T23:59:59.000Z

177

Worcester Solenoid Actuated Gas Operated MCO Isolation Valves  

Science Conference Proceedings (OSTI)

These valves are 1 inch gas-operated full-port ball valves incorporating a solenoid and limit switches as integral parts of the actuator that are used in different process streams within the CVDF hood. The valves fail closed (on loss of pressure or electrical) for MCO isolation to either reduce air in leakage or loss of He. All valves have coupling for transverse actuator mounting.

MISKA, C.R.

2000-09-03T23:59:59.000Z

178

Worchester Solenoid Actuated Gas Operated MCO Isolation Valves  

SciTech Connect

These valves are 1 inch gas-operated full-port ball valves incorporating a solenoid and limit switches as integral parts of the actuator that are used in process streams within the CVDF hood. The valves fail closed (on loss of pressure or electrical) to prevent MCO vent drain to either reduce air in-leakage or loss of He. The valves have couplings for transverse actuator mounting.

VAN KATWIJK, C.

2000-06-06T23:59:59.000Z

179

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

Science Conference Proceedings (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} pipeline rupture accident.

Sulfredge, Charles David [ORNL

2007-07-01T23:59:59.000Z

180

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

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

Separators for valve regulated lead acid batteries  

Science Conference Proceedings (OSTI)

This paper reviews some aspects of the past history of the valve regulated lead acid (VRLA) battery in relationship to microglass separators that have been used from the conception of VRLA technology. It also focuses on some aspects of compression properties of the separator.

Zguris, G.C. [Hollingsworth & Vose Co., West Groton, MT (United States)

1995-01-01T23:59:59.000Z

182

Statistical Performance Evaluation Of Soft Seat Pressure Relief Valves  

SciTech Connect

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.

2013-03-26T23:59:59.000Z

183

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

184

Technical evaluation: 300 Area steam line valve accident  

SciTech Connect

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

Subsurface safety valves: safety asset or safety liability  

SciTech Connect

This paper summarizes the methods used to compare the risk of a blowout for a well completed with a subsurface safety valve (SSSV) vs. a completion without an SSSV. These methods, which could be applied to any field, include a combination of SSSV reliability and conventional risk analyses. The Kuparuk River Unit Working Interest Owners recently formed a group to examine the risks associated with installing and maintaining SSSV's in the Kuparuk field. The group was charged with answering the question: ''Assuming Kuparuk field operating conditions, are SSSV's a safety asset, or do numerous operating and maintenance procedures make them a safety liability.'' The results indicate that for the Kuparuk River Unit, an SSSV becomes a safety liability when the mean time between SSSV failures is less than one year. Since current SSSV mean time to failure (MTTF) at Kuparuk is approximately 1000 days, they are considered a safety asset.

Busch, J.M.; Llewelyn, D.C.G.; Policky, B.J.

1983-10-01T23:59:59.000Z

186

Water cooling of HVDC thyristor valves  

SciTech Connect

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

187

The operation of LPG relief valves  

SciTech Connect

As stipulated by NFPA 58, all LPG storage containers must be equipped with one or more pressure relief devices. These devices are sized to prevent rupture of a normally charged container when exposed to fire. This paper describes in detail the functioning of the spring-loaded relief valve. The author discusses how the venting of LPGs can produce unacceptable risks and how training is a necessary part of controlling such a situation.

Stannard, J.H. Jr

1989-11-01T23:59:59.000Z

188

Novel sensorless generator control and grid fault ride-through strategies for variable-speed wind turbines and implementation on a new real-time simulation platform.  

E-Print Network (OSTI)

??The usage of MW-size variable-speed wind turbines as sources of energy has increased significantly during the last decade. Advantages over fixed-speed wind turbines include more (more)

Yang, Sheng

2010-01-01T23:59:59.000Z

189

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

190

American Valve: Proposed Penalty (2010-CW-1411) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

American Valve: Proposed Penalty (2010-CW-1411) American Valve: Proposed Penalty (2010-CW-1411) American Valve: Proposed Penalty (2010-CW-1411) September 8, 2010 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. DOE regulations require a manufacturer (which includes importers) to submit reports certifying that its products have been tested and meet the applicable water conservation standards. This civil penalty notice advises the company of the potential penalties and DOE's administrative process, including the company's right to a hearing. American Valve: Proposed Penalty (2010-CW-1411) More Documents & Publications American Valve: Order (2010-CW-1411) Afeel: Proposed Penalty (2010-CW-07/1414)

191

Spin as state variable for computation: prospects and perspectives  

Science Conference Proceedings (OSTI)

Recent experiments on spin devices like magnetic tunnel junctions (MTJ's), domain wall magnets (DWM) and spin valves have led to the possibility of having very high density on-chip memories and logic. While the possibility of having on-chip spin transfer ... Keywords: low power, spin device, state variable, ultra low voltage

Kaushik Roy

2012-07-01T23:59:59.000Z

192

Energy Savings of Variable Speed Motors  

E-Print Network (OSTI)

This paper investigates the energy savings available by utilizing variable speed motors on pump and fan applications. Conventional control of flow or pressure in process plants is normally accomplished by throttling the various streams with control valves. Depending on the system and the actual operating conditions, this throttling may consume a considerable amount of energy. The hydraulics of different systems are investigated to generalize high energy saving applications. Typical pump characteristics at varying speeds are investigated since most performance curves are only available at a constant speed. The various types of variable speed electric motors are discussed. However, the primary variable speed system recommended is a variable frequency speed system which utilizes standard induction motors. Specific cases of centrifugal pump applications and cooling tower fan service are presented. Turndown frequencies, stream factors, and electric rates are included in the evaluation. The energy savings of a variable speed system becomes significant when flow rates vary widely and the electrical rates are high.

Fishel, F. D.

1979-01-01T23:59:59.000Z

193

Predicted Effects of Tritium Exposures on Fast-Acting Piezoelectric Valves for Gas Fueling at TFTR  

SciTech Connect

The prospects for using piezoelectrically-driven valves with elastomeric or thermoplastic poppets in tritium gas service have been investigated. A modelling study of a typical valve incorporating ethylene-propylene rubber (EPR) or high density polyethylene (HDPE) was performed. Equations were developed linking applied voltage; ceramic bimorph preloading force, elastic deflection modulus, and specific deflection force (per volt applied); polymer elastic modulus, thickness, seal surface area, and compression (to make seal); elastomer compression set; thermoplastic creep modulus; and flow gap between seat and polymer tip. It was determined that, while EPR should seal the valve orifice more easily, HDPE should produce a valve flow rate vs. voltage curve less variant with time and exposure. Both should, however, be sealable and allow flow curves perturbed by less than or equal to 10% of full scale after ~100 days of exposure to 10{sup}5 Pa (1 atm) T{sub}2 gas (equivalent to ~7 x 10{sup}7 rad = 7 x 10{sup}5 Gy dosage).

Gill, J. T.; Pierce, C. W.

1985-04-01T23:59:59.000Z

194

U.S. Steam Turbine Valve Actuator Condition Assessment  

Science Conference Proceedings (OSTI)

This report provides nuclear and fossil plant personnel with current information on the inspection and assessment of steam turbine valve actuators.

2008-12-23T23:59:59.000Z

195

DEVELOPMENT OF FREEZE VALVE FOR USE IN THE MSRE  

SciTech Connect

Three types of frozen-seal valves'' were tested for possible use in the MSRE. The seal was melted by direct resistance heat, by induction heat, and by clamp-on Calrod heat. The frozen seal was made in a preformed restriction section of a standard piece of pipe by a cooling-gas jet stream directed at the restriction. All three valves performed satisfactorily through 100 test cycles. The Calrodheated valve was selected for MSRE use on the basis of simplicity of design and of operation. Two of the valves are successfully undergoing further tests on the MSRE Engineering Test Loop. (auth)

Richardson, M.

1962-02-28T23:59:59.000Z

196

American Valve: Order (2010-CW-1411) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Valve had failed to certify that certain showerhead models comply with the applicable water conservation standards. The Order adopted a Compromise Agreement, which reflected...

197

U.S. Steam Turbine Valve Metallurgy Guide  

Science Conference Proceedings (OSTI)

This report provides nuclear and fossil plant personnel with current information on the metallurgical aspects of the steam turbine valve components used in U.S. power plants.

2009-03-30T23:59:59.000Z

198

Computer Based Training: Check Valves 1.0  

Science Conference Proceedings (OSTI)

ETTM Check Valves is a computer based training module that allows users to access training when desired and review it at their own pace. It provides graphics and limited interactive features to enhance learning. The purpose of this module is to provide the user with a basis for selecting and sizing a check valve for nuclear station applications. While more than one valve type can be used for most applications, the intent is to point out the differences between check valve designs and to assist the user i...

2010-10-07T23:59:59.000Z

199

Meso-fluidic Control Valve - Oak Ridge National Laboratory  

Volume Systems Advantages: Small Size ... Meso-fluidic Control Valve-1974 Contact: Mark Reeves Oak Ridge National Laboratory P.O. Box 2008, Mail Stop ...

200

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

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

Stem control of a sliding-stem pneumatic control valve using a recurrent neural network  

Science Conference Proceedings (OSTI)

This paper presents a neural scheme for controlling an actuator of pneumatic control valve system. Bondgraph method has been used to model the actuator of control valve, in order to compare the response characteristics of valve. The proposed controller ...

Mohammad Heidari, Hadi Homaei

2013-01-01T23:59:59.000Z

202

EPRI/C-E PWR Safety Valve Test Report Volume 3: Test Results for Dresser Safety Valve Model 31739A  

Science Conference Proceedings (OSTI)

EPRI at the request of the PWR utilities developed an overall program for the testing of PWR primary system safety and relief valves. This program was in response to NUREG 0578 Item 2.1.2 and NUREG 0737 Item II.D.1.A requirements. This report documents the results of safety valve testing performed as part of the overall program at the EPRI/C-E Valve Test Facility located at Combustion Engineering's Kreisinger Development Laboratory, Windsor, Connecticut. Seven safety valves representative of those utiliz...

1983-02-01T23:59:59.000Z

203

Representing Twentieth-Century SpaceTime Climate Variability. Part I: Development of a 196190 Mean Monthly Terrestrial Climatology  

Science Conference Proceedings (OSTI)

The construction of a 0.5 lat 0.5 long surface climatology of global land areas, excluding Antarctica, is described. The climatology represents the period 196190 and comprises a suite of nine variables: precipitation, wet-day frequency, mean ...

Mark New; Mike Hulme; Phil Jones

1999-03-01T23:59:59.000Z

204

Electric actuation of a surface controlled subsea safety valve  

E-Print Network (OSTI)

The growing technology associated with petroleum equipment has lead to an increase in electrical components used to measure, adjust and control many aspects of the petroleum extraction process. This increase in electrical use has lead 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 analysis has resulted in the following important functional requirements that the SCSSV should operate within: Temperatures up to 350 F. Estimated operational life of 20 years. Peak available power of 4300 W (actual value will be much lower than this due to other power system drains). The three conceptual designs presented in this report are the following: Electric motor actuator with a solenoid latching detent. Linear actuation with a fluid reservoir locking valve. Rotational engagement with an electric locking clutch. After reviewing and comparing these concepts, the last concept was chosen to be further developed. This concept will have the least temperature sensitive components and fewer leak path problem areas. Upon completion of the detailed design phase an electric SCSSV solution has been proposed. The following is a brief list of the performance claims: Power requirement to open: 0.5 W. Time required to open valve: 10 minutes. Installable inline with 4-1/2 tubing. Operating temperature range: 20-350 F. H?S service certified. Hold open energy requirements 0~0.2 W. There are however practical issues that must be addressed to ensure reliable and satisfactory performance of the SCSSV. The actual efficiency of the cylindrical cam mechanism and reliability of the torque overload clutch must be empirically determined due to the number of theoretical assumptions used. Thus these items should be thoroughly tested in order to produce a reliable and satisfactory SCSSV. It is with these claims and working issue that this electrically converted SCSSV be fully developed and installed for electrical petroleum production systems.

Bartlett, Timothy Joseph

2002-01-01T23:59:59.000Z

205

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

206

Giant magnetoresistance in organic spin valves  

SciTech Connect

Interfacial diffusion between magnetic electrodes and organic spacer layers is a serious problem in the organic spintronics which complicates attempts to understand the spin-dependent transport mechanism and hurts the achievement of a desirably high magnetoresistance (MR). We deposit nanodots instead of atoms onto the organic layer using buffer layer assist growth. Spin valves using this method exhibit a sharper interface and a giant MR of up to {approx}300%. Analysis of the current-voltage characteristics indicates that the spin-dependent carrier injection correlates with the observed MR.

Sun, Da-Li [ORNL; Yin, Lifeng [ORNL; Sun, Chengjun [ORNL; Guo, Hangwen [ORNL; Gai, Zheng [ORNL; Zhang, Xiaoguang [ORNL; Ward, Thomas Z [ORNL; Cheng, Zhaohua [Chinese Academy of Sciences; Shen, Jian [ORNL

2010-01-01T23:59:59.000Z

207

Effect of reactor conditions on MSIV (main steam isolation valves)-ATWS power level  

SciTech Connect

In a boiling water reactor (BWR) when there is closure of the main steam isolation valves (MSIVs), the energy generated in the core will be transferred to the pressure suppression pool (PSP) via steam flows out of the relief valves. The pool has limited capacity as a heat sink and hence, if there is no reactor trip (an ATWS event), there is the possibility that the pool temperature may rise beyond acceptable limits. The present study was undertaken to determine how the initial reactor conditions affect the power during an MSIV-ATWS event. The time of interest is during the 20-30 minute period when it is assumed that the reactor is in a quasi-equilibrium condition with the water level and pressure fixed, natural circulation conditions and no control rod movement or significant boron in the core. The initial conditions of interest are the time during the cycle and the operating state. 4 refs., 2 tabs.

Diamond, D.J.

1987-01-01T23:59:59.000Z

208

Closed Loop Test Facility for hot dirty gas valves  

SciTech Connect

A design study of a closed loop test facility for eight-inch hot dirty gas valves is presented. The objective of the facility is to quality valves for use in coal gasifiers, combined cycle plants, and pressurized fluid bed combustors. Outline sketches and estimated costs are presented for the selected design.

Not Available

1980-02-06T23:59:59.000Z

209

Classification of prosthetic heart valve sounds: A parametric approach  

Science Conference Proceedings (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

J. V. Candy; H. E. Jones

1995-01-01T23:59:59.000Z

210

Cam-driven valve system for steam turbines  

SciTech Connect

This patent describes, in a steam turbine system including a source of motive steam and a turbine adapted to operate at less than a full load, the turbine including an improved cam-driven valve system for activating a varying number of steam control valves to permit transferring between a maximum arc-admission mode and a minimum arc-admission mode. It comprises: a steam chest for receiving the motive steam from the source, the steam chest including a plurality of valves connected to a corresponding turbine section and set for a minimum admission of motive steam into the turbine below 100 percent; a first cam lift means for actuating a portion of the valves and second cam lift means for actuating the remainder of the valves.

Silvestri, G.J. Jr.

1990-02-27T23:59:59.000Z

211

A characterization of check valve degradation and failure experience in the nuclear power industry: 1991 Failures, Volume 2  

SciTech Connect

Review and characterization of check valve failures taken from the Institute of Nuclear Power Operation`s Nuclear Plant Reliability Data System was performed in accordance with part two of a three-phase project sponsored by the US Nuclear Regulatory Commission. The analysis was performed for check valve failures occurring in 1991 and is intended to update the previous analysis performed for the time period 1984--1990. To maintain consistency and for ease of the 1991 analysis presents the same parameters and cross-correlations in essentially the same format as the 1984--1990 study. Additional data was obtained for the 1991 analysis, including information related to specific check valve type. This information is presented in a separate section of the report.

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

1995-07-01T23:59:59.000Z

212

Variable Screw Compressor, Variable Screw Compressor Suppliers ...  

U.S. Energy Information Administration (EIA)

Variable Screw Compressor Suppliers & air compressor Manufacturers Directory. Source Top Quality Variable Screw Compressor Suppliers, air ...

213

Engine valve and method of producing the same  

SciTech Connect

An engine valve of an internal combustion engine is described which consists of: a hollow tube member formed of a drawn steel tube, the hollow tube member having a central portion comprising a tubular body, and a first end part which is flared outwardly and includes an open end peripheral portion at the extreme end of the first end part, the hollow tube member tubular body constituting a valve stem section; a generally disc-shaped lid member made of metal and having a peripheral portion integrally connected with the open end peripheral portion of the hollow tube member, the lid member and the first end part of the hollow tube member constituting a valve head section; and a stem end member made of metal and integrally connected with a second part of the hollow tube member; a filler metal comprising stellite disposed in contact with the open end peripheral portion of the hollow tube member first end part and the peripheral portion of the disc-shaped lid member to secure together the hollow tube member and the lid member to thereby form the integral connection, the stellite filler metal being a wear and corrosion resistant nonferrous alloy, the filler metal being formed as a padding having a peripheral surface including a valve face for contacting a valve seat of an engine; and a filling comprising an aluminum alloy containing silicon, the filling being disposed in the valve head section to fill the valve head section.

Hayashi, Y.

1986-07-01T23:59:59.000Z

214

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

215

Control system for the turbomolecular pumping stations and sector valves of the CERN Intersecting Storage Rings  

E-Print Network (OSTI)

Control system for the turbomolecular pumping stations and sector valves of the CERN Intersecting Storage Rings

Grbner, Oswald

1971-01-01T23:59:59.000Z

216

Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field  

DOE Patents (OSTI)

One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.

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

1993-08-17T23:59:59.000Z

217

Noninvasive valve monitor using constant magnetic and/or DC electromagnetic field  

SciTech Connect

One or more sources of steady magnetic field are carefully located on the outside of a valve body. The constant magnetic field is transmitted into the valve body and valve internals. A magnetic field detector carefully located on the outside of the valve body detects the intensity of the magnetic field at its location. As the position of a valve internal part is changed, there is an alteration in the magnetic field in the valve, and a consequent change in the detected magnetic field. Changes in the detected signal provide an indication of the position and motion of the valve internals.

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

1993-01-01T23:59:59.000Z

218

Analog and digital control of an electronic throttle valve  

E-Print Network (OSTI)

Two electronic throttler controllers were designed and implemented for an automotive throttle valve on a four-cylinder, spark-ignition gasoline engine. The first controller was designed using operational amplifiers and ...

Martins, Toms V

2012-01-01T23:59:59.000Z

219

Replace Pressure-Reducing Valves with Backpressure Turbogenerators  

SciTech Connect

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

220

Technical Repair Guide for Rotork Valve Actuators "NA" Range Models  

Science Conference Proceedings (OSTI)

This guide provides comprehensive technical information on Rotork valve actuator operation, maintenance, testing, and troubleshooting. Its design provides the user with a uniform methodology to reduce human errors and increase actuator reliability.

1995-12-31T23:59:59.000Z

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.


221

Efforts by the nuclear industry to evaluate check valve failures  

SciTech Connect

Recent studies identified approximately 4000 check valve failures that occurred from 1984-1991. Of these, approximately 1600 were determined to be significant enough to require further analysis. This is to be compared with the existing check valve population of nearly 21,000 valves. The strategy proposed in this paper is to establish a refined, centralized check valve failure/reliability database based in part on existing Institute of Nuclear Power Operations (INPO) Nuclear Plant Reliability Data System (NPRDS) data. Ideally the database would be maintained in a central location, augmented with specific component information, overall reliability information, and updated at least biannually. The data would be available to sort and search as desired. The conceptual plan is provided and possible uses of the database are given.

Hart, K.; McElhaney, K.L.; Casada, D.A.

1994-12-31T23:59:59.000Z

222

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.

223

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

224

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

225

Low-Frequency Variability in Shallow-Water Models of the Wind-Driven Ocean Circulation. Part II: Time-Dependent Solutions  

Science Conference Proceedings (OSTI)

The time-dependent wind-driven ocean circulation is investigated for both a rectangular and a North Atlanticshaped basin. Multiple steady states in a 2-layer shallow-water model and their dependence on various parameters and other model ...

Eric Simonnet; Michael Ghil; Kayo Ide; Roger Temam; Shouhong Wang

2003-04-01T23:59:59.000Z

226

Steam Turbine Casing and Valve Body Repair Guidelines  

Science Conference Proceedings (OSTI)

Todays flexible mode of operation can result in damage to heavy-section components, such as steam turbine and valve casings. Thus, owners and operators are often faced with repairing a critical component. This report is part of a set of documents that address the key areas in the asset management of steam turbine casings and valve bodiesnondestructive evaluation and damage detection, repair, and life ...

2013-12-14T23:59:59.000Z

227

Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves  

SciTech Connect

1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

MISKA, C.R.

2000-09-03T23:59:59.000Z

228

Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves  

SciTech Connect

1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fall closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

VAN KATWIJK, C.

2000-10-23T23:59:59.000Z

229

Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves  

SciTech Connect

1 inch gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

MISKA, C.R.

2000-11-13T23:59:59.000Z

230

Worcester 1 Inch Solenoid Actuated Gas Operated SCHe System Valves  

SciTech Connect

1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated.

VAN KATWIJK, C.

2000-06-06T23:59:59.000Z

231

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

232

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

233

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

234

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

235

Design and Testing of Vacuum Breaker Check Valve for Simplified Boiling Water Reactor  

Science Conference Proceedings (OSTI)

A new design of the vacuum breaker check valve was developed to replace the mechanical valve in a simplified boiling water reactor. Scaling and design calculations were performed to obtain the geometry of new passive hydraulic vacuum breaker check valve. In order to check the valve performance, a RELAP5 model of the simplified boiling water reactor system with the new valve was developed. The valve was implemented in an integral facility, PUMA and was tested for large break loss of coolant accident. (authors)

Ishii, M.; Xu, Y.; Revankar, S.T. [Purdue University, West Lafayette, IN 47907 (United States)

2002-07-01T23:59:59.000Z

236

ISOLOK VALVE ACCEPTANCE TESTING FOR DWPF SME SAMPLING PROCESS  

Science Conference Proceedings (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

237

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

J. Marvin Herndon

2005-10-04T23:59:59.000Z

238

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

Herndon, J M

2005-01-01T23:59:59.000Z

239

Important Variables  

Science Conference Proceedings (OSTI)

Table 4   Environmental data for the ISO CORRAG exposures...temperature and time of wetness (TOW) from weather station. (b) SO 2 from the hourly

240

Quasi-Static Hydraulic Control Systems and Energy Savings Potential Using Independent Metering Four-Valve Assembly Configuration .  

E-Print Network (OSTI)

??In this research, the four valve independent metering configuration is to be investigated. The Independent metering concept will be emphasized and compared to spool valve (more)

Shenouda, Amir

2006-01-01T23:59:59.000Z

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.


241

Performance simulation of R410A air conditioning system with variable speeds  

Science Conference Proceedings (OSTI)

With the implementation of "Montreal protocol on substances that deplete the ozone layer", HCFCs especially R22 will be phased out. R410A (R32/R125,50/50wt%), as one alternative of R22, is a promising refrigerant for air conditioning ... Keywords: R410A, air conditioning, electronic expansion valve, performance, refrigerants, system simulation, variable speeds

Zaoxiao Zhang; Yongzhang Yu; Leping Zhang

2004-12-01T23:59:59.000Z

242

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

243

Processing of prosthetic heart valve sounds for single leg separation classification  

Science Conference Proceedings (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

J. V. Candy; H. E. Jones

1995-01-01T23:59:59.000Z

244

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

245

Technical Repair Guidelines for the Limitorque Model SMB-00 Valve Actuator  

Science Conference Proceedings (OSTI)

This technical repair guideline (TRG) is the second in a series of documents devoted to comprehensive maintenance and repair of the motor-operated Limitorque SMB-00 valve actuator. The Limitorque SMB-00 valve actuator is mounted on a nonrotating rising stem valve and is applicable to other types of valves and installation arrangements. This report was written with the latest available information, however, changes to the actuator's design, parts availability, etc. may supersede this document but will not...

1995-06-30T23:59:59.000Z

246

Water Consumption from Freeze Protection Valves for Solar Water Heating Systems  

DOE Green Energy (OSTI)

Conference paper regarding research in the use of freeze protection valves for solar domestic water heating systems in cold climates.

Burch, J.; Salasovich, J.

2005-12-01T23:59:59.000Z

247

Surfacing of the parts of Christmas tree valves  

SciTech Connect

The authors discuss the strengthening of Christmas trees for service conditions, in particular, the method of plasma spraying of the sealing surfaces of the gates of the valves with hard corrosion resistant alloys. Most frequently, cobalt- (stellite), nickel- (colmonoy), and iron-base alloys are used for surfacing. A plan is shown of the area for plasma surfacing in one of the petroleum machinery plants. It is found that the hardening of the sealing surface of gate valve parts by plasma powder surfacing with self-fluxing nickel alloys increases the reliability and life of well-head equipment.

Mordynskii, V.B.; Barsukov, V.P.; Iskakhov, A.R.; Komarcheva, E.S.

1987-07-01T23:59:59.000Z

248

A study on the use of multiple surrogate models in valve design  

Science Conference Proceedings (OSTI)

Nowadays, the use of computational fluid dynamics (CFD) in the design of valves is very common. Despite the continuing growth of computing capability, the computational cost of complex three-dimensional CFD analysis of butterfly valve maintains high, ... Keywords: DOE, butterfly valve, error analysis, multiple surrogate models, optimization

Xue Guan Song; Jeong Ju Choi; Joon-Ho Lee; Young Chul Park

2011-09-01T23:59:59.000Z

249

Probability of Safety Valve Failure-to-Reseat Following Steam and Liquid Relief: Quantitative Expert Elicitation  

Science Conference Proceedings (OSTI)

This report describes a quantitative expert elicitation to assist in the determination of the failure probability of safety valves to reseat following steam and/or liquid relief. The expert elicitation process improves the estimation of the safety valve failure-to-reseat probability and is based on expert judgment, safety valve testing programs, and experience.

2004-08-31T23:59:59.000Z

250

Worcester 1 Inch Solenoid Actuated Gas Operated VPS System Ball Valve  

SciTech Connect

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

VAN KATWIJK, C.

2000-06-06T23:59:59.000Z

251

Worcester 1 Inch Solenoid Actuated Gas Operated VPS System Ball Valve  

Science Conference Proceedings (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

252

TIMING APPARATUS  

DOE Patents (OSTI)

The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

Bennett, A.E.; Geisow, J.C.H.

1956-04-17T23:59:59.000Z

253

Control of HCCI engine fueled with gasoline with electro-hydraulic variable valve system  

Science Conference Proceedings (OSTI)

The homogeneous charge compression ignition-HCCI (also to be known as controlled auto ignition-CAI) engine concept has the potential to be highly efficient and to produce low NOx emissions whilst conventional engine suffered from consumption and emission ... Keywords: HCCI, gasoline, trapped residual gas

Gao Fengjun; Guo Yingnan; Liu Fafa; Li Hua; Ji Honggang; Tan Manzhi

2010-03-01T23:59:59.000Z

254

Workshop on gate valve pressure locking and thermal binding  

SciTech Connect

The purpose of the Workshop on Gate Valve Pressure Locking and Thermal Binding was to discuss pressure locking and thermal binding issues that could lead to inoperable gate valves in both boiling water and pressurized water reactors. The goal was to foster exchange of information to develop the technical bases to understand the phenomena, identify the components that are susceptible, discuss actual events, discuss the safety significance, and illustrate known corrective actions that can prevent or limit the occurrence of pressure locking or thermal binding. The presentations were structured to cover U.S. Nuclear Regulatory Commission staff evaluation of operating experience and planned regulatory activity; industry discussions of specific events, including foreign experience, and efforts to determine causes and alleviate the affects; and valve vendor experience and recommended corrective action. The discussions indicated that identifying valves susceptible to pressure locking and thermal binding was a complex process involving knowledge of components, systems, and plant operations. The corrective action options are varied and straightforward.

Brown, E.J.

1995-07-01T23:59:59.000Z

255

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

SciTech Connect

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

256

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

Science Conference Proceedings (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

257

Reversible Record Breaking and Variability: Temperature Distributions across the Globe  

Science Conference Proceedings (OSTI)

Based on counts of record highs and lows, and employing reversibility in time, an approach to examining natural variability is proposed. The focus is on intrinsic variability; that is, variance separated from the trend in the mean. A variability ...

Amalia Anderson; Alexander Kostinski

2010-08-01T23:59:59.000Z

258

System for minimizing valve throttling losses in a steam turbine power plant  

SciTech Connect

A system which integrates the controls of a steam turbine power plant for minimizing power plant energy losses substantially caused by steam flow valve throttling is disclosed. The steam turbine power plant includes boiler pressure controls for controlling the boiler throttle pressure of a steam producing boiler and turbine-generator controls for positioning a plurality of turbine steam admission values to regulate the steam flow conducted through a steam turbine which governs the electrical energy generated by an electrical generator at a desired power generation level. The turbine-generator controls predetermine a plurality of valve position states to establish a predetermined valve grouping sequential positioning pattern for the steam admission valves to regulate steam flow through the steam turbine across the range of power generation, each predetermined state substantially corresponding to a minimum of valve throttling losses. The steam admission valves may be positioned at a present valve position state, which is other than one of the predetermined states, as a result of a change in desired power generation level. The disclosed system responds to this condition by governing the boiler pressure controls to adjust the boiler throttle pressure at a desired rate and in a direction to cause steam admission valves to be repositioned according to the sequential positioning pattern to a selected one of the predetermined efficient valve position states. The repositioning of the steam admission valves is performed by maintaining the generated energy substantially at the new desired power generation level.

Stern, L.P.; Johnson, S.J.

1979-12-18T23:59:59.000Z

259

System to inject steam and produce oil from the same wellbore through downhole valve switching. Final report  

SciTech Connect

Through direct contacts with many California Operators, the potential market for this technology and hardware was more closely defined. The largest market might be for re-entry into existing but shut-in wells, equipped with 7{double_prime}OD cemented casings, for which a suitable configuration was designed. For field-testing any prototype Downhole equipment, however, Operators and Service Companies prefer to start with a new well, for better control of the well characteristics. In the relatively shallow reservoirs where Steam injection is currently used with success, the additional drilling cost, in soft formations, is sufficiently small that this became the main design case. Substantial savings were obtained by reducing the number of Downhole valves from two to one and by replacing the twin hydraulically-controlled ball or flapper-type valves with a single sliding sleeve valve, operated by wireline. Laboratory tests conducted at UC-Berkeley confirmed the satisfactory operation of this type of valve with wet steam over extended periods. Low reservoir pressures dictated the use of artificial lift methods, with rod pumps considered the most economical. The availability of live steam downhole at all times is, however, a major advantage which led to the selection of a combined method of artificial lift: (1) steam-lift of the produced fluids up to the kick-off point of the medium curvature drainholes, (2) dumping of the produced fluids into a vertical separator/sump below the kick-off points, (3) vertical rod pumping of the liquid phases from the downhole separator/sump to the surface through a dedicated production tubing.

Not Available

1994-10-01T23:59:59.000Z

260

Application of a Plasma Powder Welding to engine valves  

SciTech Connect

In hardfacing of automobile engine valves made of heat resisting steel such as 21-4N, conventional oxy-acetylene gase welding has been currently conducted manually by well trained operators because of using cast Stellite rods as the filler. In accordance with the strong demands of automatic welding, the authors newly developed an automatically controlled Plasma Powder Welding (PPW) system. This system is characterized by the application of a high thermal density plasma arc as heat source and by using power filler which melts more easily than bar cast rods. Moreover, this PPW system has been applied to the automotive engine valve production line and resulted in the great contribution to manpower saving.

Takeuchi, Y.; Nagata, M.

1985-01-01T23:59:59.000Z

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.


261

Valve Regulated Lead Acid (VRLA) Battery Qualification Assessment  

Science Conference Proceedings (OSTI)

Valve-regulated lead acid (VRLA) batteries have been proposed as a prospective dc power source for Class 1E service in passive nuclear plants. However, they are not currently covered by IEEE Standard 535, which addresses qualification for this service. Furthermore, there are reports of significant failure modes or mechanisms beyond the predominant failure mode of grid corrosion of the positive plate associated with vented lead acid (VLA) batteries.

2009-11-06T23:59:59.000Z

262

Application of Nanocoatings for Erosion Protection of Valve Stems  

Science Conference Proceedings (OSTI)

Damage in steam turbine valve stems is attributed to erosion from the impingement of spalled oxides present in the high-temperature flowing steam environment. Utilities and turbine engineers are currently managing the erosion and damage issues through component replacement (in some extreme cases, with component lives shorter than one year). With limited success, numerous materials have been examined as alternatives to extend component life. Erosion-resistant nanocoatings have shown superior performance t...

2010-12-19T23:59:59.000Z

263

Diffusion based degradation mechanisms in giant magnetoresistive spin valves  

Science Conference Proceedings (OSTI)

Spin valve systems based on the giant magnetoresistive effect as used, for example, in hard disks and automotive applications consist of several functional metallic thin film layers. We have identified by secondary ion mass spectrometry two main degradation mechanisms: one is related to oxygen diffusion through a protective cap layer and the other one is interdiffusion directly at the functional layers of the giant magnetoresistive stack. By choosing a suitable material as cap layer (TaN), the oxidation effect can be suppressed.

Hawraneck, Matthias [Department of Sense and Control, Infineon Technologies AG, 85579 Neubiberg (Germany); Institute for Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany); Zimmer, Juergen; Raberg, Wolfgang; Pruegl, Klemens; Schmitt, Stephan; Bever, Thomas [Department of Sense and Control, Infineon Technologies AG, 85579 Neubiberg (Germany); Flege, Stefan; Alff, Lambert [Institute for Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

2008-07-07T23:59:59.000Z

264

Steam Turbine Valve Actuator Condition Assessment: 2013 Update  

Science Conference Proceedings (OSTI)

This report provides nuclear and fossil plant personnel with current information on the inspection and assessment of steam turbine valve actuators. It covers the actuators that are typically found on the turbines of the two major U.S. original equipment manufacturers (OEMs), as well as those of several non-U.S. OEMs. The scope encompasses both mechanical hydraulic control (MHC) and electronic hydraulic control (EHC) types of hydraulic ...

2013-07-25T23:59:59.000Z

265

Safety and Relief Valve Testing and Maintenance Guide  

Science Conference Proceedings (OSTI)

This guide gives a broad overview of self actuated and power operated pressure relief devices (PRDs) -- safety, relief, safety relief, and power-operated relief valves -- and their application and maintenance. The non-reclosing devices, like the rupture discs, are outside the scope of this guide. The information in this guide, though directed towards the nuclear power plant personnel, will assist all power plant personnel responsible for the maintenance of PRDs. This guide can also be used by training in...

1996-10-02T23:59:59.000Z

266

The lubrication of engine valve trains equipped with ceramicized followers  

Science Conference Proceedings (OSTI)

The valve train wear characteristics of motored 2.2l and 2.3l engines were examined using ceramic and conventional metal cam followers. Under regular wear conditions with fully formulated motor oils, minimal wear was observed on the metal cam lobes running with either the ceramicized or metal followers. Running under chemically accelerated wear conditions with low quality oil, however, cam lobe wear with ceramicized followers was observed to be significantly less than that with metal followers. The difference in wear was diminished when testing high quality oils under chemically accelerated conditions. Typical testing revealed that the metal follower pads quickly developed considerable wear in a characteristic pattern, while the ceramic followers pads quickly developed considerable were in a characteristic pattern, while the ceramic followers exhibited only slight polishing. Scanning electron photographs revealed details of the used ceramic surfaces, and that wear took place by polishing and by intergranular fracture with subsequent material removal. Engine wear is a major factor that limits the life of today's passenger cars. Particularly for the newer models that have smaller but higher speed and output engines incorporating current designs such as overhead camshafts, 4-valves per cylinder and turbochargers, the valve train represents one of the highest wear components within an engine. In light of the trend towards extended drivetrain warranties, there is a strong demand for lubricant suppliers to develop engine oils with improved antiwear performance. In a parallel effort, automotive engine and component manufacturers are enhancing valve train durability with technologies that include roller followers and the use of advanced ceramic materials.

Blahey, A.G.; Habeeb, J.J.; Rogers, W.N.< 110> The lubrication of engine valve trains equipped with ceramicized followers.

1990-01-01T23:59:59.000Z

267

Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies Pub ID 38707 Title Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies Status Distributed Communication Type ORNL report ORNL Review? Scientific communication that requires ORNL review Information Category Protected CRADA Information ORNL Report Classification Final Expanding Robust HCCI Operation with Advanced Valve and Fuel Control Technologies  

SciTech Connect

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.; Confer, K. (Delphi Automotive Systems)

2012-09-11T23:59:59.000Z

268

Sliding-gate valve for use with abrasive materials  

DOE Patents (OSTI)

The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

Ayers, Jr., William J. (Morgantown, WV); Carter, Charles R. (Fairmont, WV); Griffith, Richard A. (Morgantown, WV); Loomis, Richard B. (Bruceton Mills, WV); Notestein, John E. (Morgantown, WV)

1985-01-01T23:59:59.000Z

269

Double Shell Tank (DST) Transfer Valving Subsystem Specification  

Science Conference Proceedings (OSTI)

This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Valving Subsystem that supports the first phase of Waste Feed Delivery. This specification establishes the performance requirements and provides references to the requisite codes and standards to be applied during design of the Double-Shell Tank (DST) Transfer Valving Subsystem that supports the first phase of Waste Feed Delivery (WFD). The DST Transfer Valving Subsystem routes waste and other media (e.g., diluent, flush water, filtered raw water) among DSTs and from the low-activity waste (LAW) and high-level waste (HLW) feed staging tanks to the River Protection Project (RPP) Privatization Contractor facility, where it will be processed into an immobilized waste form. This specification is intended to be the basis for new projects/installations (W-521, etc.). This specification is not intended to retroactively affect previously established project design criteria without specific direction by the program.

GRAVES, C.E.

2000-03-22T23:59:59.000Z

270

A tritium-compatible piezoelectric valve for the tokamak fusion test reactor  

SciTech Connect

This work describes modifications made to a commercial piezoelectric valve to make it sufficiently tritium compatible for the TFTR trritium injection scenario. The results of testing the valve for leakage and performance following a series of progressively more severe tritium exposures are also presented. Finally, a proposal for a totally radiation-compatible piezoelectric valve, suitable for tritium-burning fusion machines of the future, is decribed. 9 refs., 2 figs., 1 tab.

Coffin, D.O.; Cole, S.P.; Wilhelm, R.C.

1988-02-01T23:59:59.000Z

271

Investigation of Main Steam Safety Valve Seat/Nozzle Surface Treatments  

Science Conference Proceedings (OSTI)

This report discusses continued research in evaluating the main steam safety valve (MSSV) high first lift phenomenon (seat sticking) experienced in some Dresser 3700 series steam safety valves. Previous EPRI research (Report TR-113560) concluded that the high first lift phenomenon is the result of adhesion of the valve disk to the nozzle seat resulting in additional opening force to separate the disk from the nozzle. Replacement of the disks with disks incorporating pre-oxidized Inconel X-750 material on...

2003-05-30T23:59:59.000Z

272

Computer Based Training: Engineering Technical Training Modules - Valve Actuator v1.0  

Science Conference Proceedings (OSTI)

Valve Actuator ETTM, Version 1.0 is a computer-based training module that allows users to access training when desired and review it at their own pace. The purpose of this training module is to provide a basic understanding of the various types of power valve actuators used in nuclear power plants and their characteristics. This module will also provide an understanding of valve actuator applications, selection, accessory requirements, and capabilities. This computer-based training (CBT) module is intend...

2009-12-04T23:59:59.000Z

273

Computer Based Training: Engineering Technical Training Module (ETTM) Relief and Safety Valves v1.0  

Science Conference Proceedings (OSTI)

Relief and Safety Valves ETTM, Version 1.0 is a computer45based training module that allows users to access training when desired and review it at their own pace. This module provides information about the types of valves, requirements surrounding their performance, characteristics and selection of these valves, as well as testing requirements. Additionally, it describes design considerations and system interactions. This training should be used for position specific and/or continuing training for indivi...

2009-11-02T23:59:59.000Z

274

Safety Valve Performance Considerations During High-Pressure Station Black-Out Severe Accidents  

Science Conference Proceedings (OSTI)

An assessment of the operating history and test performance of pressurizer safety valves (PSVs) and main steam safety valves (MSSVs) has led to new conclusions on their expected performance during high-pressure station blackout (SBO) severe accident conditions. This report updates conclusions documented in Volume I, focusing on thermal-hydraulic considerations surrounding the reactor coolant system response to an SBO and valve lifts during an SBO event. The report also reconsiders PSV and MSSV tests and ...

1998-01-02T23:59:59.000Z

275

EPRI/C-E PWR Safety Valve Test Report, Volume 10: Piping Structural Response Results  

Science Conference Proceedings (OSTI)

EPRI at the request of the PWR Utilities developed an overall program for the testing of PWR primary system safety and relief valves. This program was in response to NUREG 0578 Item 2.1.2 and NUREG 0737 Item II.D.l.A requirements.This report documents the results of safety valve testing performed as part of the overall program at the EPRI/C-E Valve Test Facility located at Combustion Engineering's Kreisinger Development Laboratory, Windsor, Connecticut. Seven safety valves ...

1983-04-01T23:59:59.000Z

276

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

DOE Patents (OSTI)

This invention is comprised of a piezoelectric valve in a gas delivery system which 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; and insulating ball normally biased by a preload spring against the piezoceramic element; and inlet gas port positioned such that upon admission of inlet gas into the valve. The piezoceramic element is positively seated. The inelt gas port is located only on the side of the piezoceramic element opposite the seal.

Wright, K.E.

1993-12-31T23:59:59.000Z

277

Definition: Variable Peak Pricing | Open Energy Information  

Open Energy Info (EERE)

Variable Peak Pricing Variable Peak Pricing Jump to: navigation, search Dictionary.png Variable Peak Pricing Variable Peak Pricing (VPP) is a hybrid of time-of-use and real-time pricing where the different periods for pricing are defined in advance (e.g., on-peak=6 hours for summer weekday afternoon; off-peak= all other hours in the summer months), but the price established for the on-peak period varies by utility and market conditions.[1] Related Terms real-time pricing References ↑ https://www.smartgrid.gov/category/technology/variable_peak_pricing [[C LikeLike UnlikeLike You like this.Sign Up to see what your friends like. ategory: Smart Grid Definitionssmart grid,off-peak,on-peak,smart grid, |Template:BASEPAGENAME]]smart grid,off-peak,on-peak,smart grid, Retrieved from "http://en.openei.org/w/index.php?title=Definition:Variable_Peak_Pricing&oldid=50262

278

Observation and implications of magnetic domains in lateral spin valves  

Science Conference Proceedings (OSTI)

Co/Cu/Co lateral spin valves (LSV), with Co being the topmost layer, are in situ prepared and measured under ultrahigh vacuum conditions. The clean process yields a non-local spin signal of 0.9 m{Omega}. Scanning electron microscopy with polarization analysis (SEMPA) reveals domain structures in both magnetic electrodes that depend on the LSV dimensions. The spin signal correlates to SEMPA images as well as the anisotropic magnetoresistance of both Co magnets, revealing a strong impact of multi-domain states on the spin signal.

Mennig, J.; Matthes, F.; Buergler, D. E.; Schneider, C. M. [Peter Gruenberg Institute, Electronic Properties (PGI-6) and Juelich-Aachen Research Alliance, Fundamentals of Future Information Technology (JARA-FIT), Forschungszentrum Juelich GmbH, Juelich D-52425 (Germany)

2012-04-01T23:59:59.000Z

279

Endothelial Progenitor Cells as a Sole Source for Ex Vivo Seeding of Tissue-Engineered Heart Valves  

E-Print Network (OSTI)

Purposes: We investigated whether circulating endothelial progenitor cells (EPCs) can be used as a cell source for the creation of a tissue-engineered heart valve (TEHV). Methods: Trileaflet valved conduits were fabricated ...

Sales, Virna L.

280

System and method for individually testing valves in a steam turbine trip control system  

SciTech Connect

This patent describes a steam turbine power plant. It comprises: a steam generator; a steam turbine adapted to receive steam form the steam generator; a throttle valve for regulating the flow of the steam received by the steam turbine; and an electro-hydraulic trip control system for causing the throttle valve to close when a predetermined condition has been reached.

Hurley, J.D.

1992-07-28T23:59:59.000Z

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

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

282

KIVA-3V: A block-structured KIVA program for engines with vertical or canted valves  

DOE Green Energy (OSTI)

This report describes an extended version of KIVA-3, known as KIVA-3V, that can model any number of vertical or canted valves in the cylinder head of an internal combustion (IC) engine. The valves are treated as solid objects that move through the mesh using the familiar snapper technique used for piston motion in KIVA-3. Because the valve motion is modeled exactly, and the valve shapes are as exact as the grid resolution will allow, the accuracy of the valve model is commensurate with that of the rest of the program. Other new features in KIVA-3V include a particle-based liquid wall film model, a new sorting subroutine that is linear in the number of nodes and preserves the original storage sequence, a mixing-controlled turbulent combustion model, and an optional RNG {kappa}-{epsilon} turbulence model. All features and capabilities of the original KIVA-3 have been retained. The grid generator, K3PREP, has been expanded to support the generation of grids with valves, along with the shaping of valve ports and runners. Graphics output options have also been expanded. The report discusses the new features, and includes four examples of grids with vertical and canted valves that are representative of IC engines in use today.

Amsden, A.A.

1997-07-01T23:59:59.000Z

283

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

SciTech Connect

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

284

A New Operational Tests Circuit for Testing 660kV UHVDC Thyristor Valves  

Science Conference Proceedings (OSTI)

Operational test is an important measure which can guarantee safe and stable operation of UHVDC thyristor valves. HVDC thyristor modules can be performed either in a six-pulse back-to-back test circuit or in a synthetic test circuit. UHVDC thyristor ... Keywords: HVDC thyristor valve, operational tests, synthetic test circuit

Ting Xie; Tang Guang-fu; Zha Kun-peng; Gao Chong

2010-06-01T23:59:59.000Z

285

Nuclear Maintenance Applications Center: Air-Operated Valve Diagnostic Testing Guide  

Science Conference Proceedings (OSTI)

This report provides information for personnel involved in the performance of air-operated valve (AOV) diagnostic testing, including the benefits of using diagnostics to understand valve health and to tie information into preventive maintenance programs. It provides insights for experienced personnel as well as basic information, guidance, and instructions for personnel assigned to perform, analyze, or purchase diagnostic test equipment.

2011-12-23T23:59:59.000Z

286

Fault Detection, Diagnosis and Prediction in Electrical Valves Using Self-Organizing Maps  

Science Conference Proceedings (OSTI)

This paper presents a proactive maintenance scheme for fault detection, diagnosis and prediction in electrical valves. The proposed scheme is validated with a case study, considering a specific valve used for controlling the oil flow in a distribution ... Keywords: Fault prediction, Proactive maintenance, Self-organizing maps, Test of electromechanical systems

Luiz Fernando Gonalves; Jefferson Luiz Bosa; Tiago Roberto Balen; Marcelo Soares Lubaszewski; Eduardo Luis Schneider; Renato Ventura Henriques

2011-08-01T23:59:59.000Z

287

Endurance Tests of Valves With Cobalt-Free Hardfacing Alloys: PWR Phase Final Report  

Science Conference Proceedings (OSTI)

Gate valves hard-faced with three galling-resistant iron-base alloys and a cobalt-base standard were subjected to demanding cycling conditions in an environment simulating typical PWR primary chemistry conditions. Extensive nondestructive and destructive examinations showed that all valves with iron-base trim performed better than the cobalt-base standard after 1900 operating cycles.

1992-05-01T23:59:59.000Z

288

Evaluation of wear resistant ceramic valve seats in gas-fueled power generation engines. Topical report, December 1991-April 1994  

SciTech Connect

This project is directed at the reduction of valve recession in natural gas-fueled engines. Ceramic valve seat inserts have been procured, installed in a Caterpillar G3516 natural gas generator set, and tested for 1000 hours. Two different silicon nitride materials are being utilized for the valve seats in addition to stock Eatonite metallic inserts. Three valve face materials are being tested. These include stock Caterpillar stellite 1 faced, stellite 6 faced, and unfaced valves. A test matrix was used to allow comparison of all three valve face materials in combination with all three insert materials. The testing is scheduled to continue for an additional 7000 hours. No problems have been encountered with the test materials. In general, it has been shown that two types of silicon nitride materials have at least short term durability in engine operation. Neither material has exhibited any deficiencies thus far. An economic analysis spreadsheet has been created to calculate potential cost savings potential using ceramic valve seat inserts. Valve recession data for the first 1000 hours shows expected trends. Exhaust valve positions are wearing more than intake valve positions. If the intake positions and all positions with unfaced valve are ignored, then ceramic inserts paired with Stellite 1 valves show the most wear.

Burrahm, R.W.; Branecky, R.J.; Sui, P.C.; Latusek, J.P.; Hsu, S.M.

1994-12-01T23:59:59.000Z

289

Why Pressure Reducing Valves (PVR's) are costing you money  

E-Print Network (OSTI)

Throughout many manufacturing facilities, colleges, commercial sites or industrial complexes, pressure reducing valves (PRV's) provide a cheap, reliable method to produce low pressure steam from a high pressure source in order to meet a process requirement or heating load. This simple method of expanding steam in a PRV creates no work and supplies the same heat content available in the high pressure steam at a more manageable low pressure. What if you could produce the same low pressure steam while saving hundreds of thousands of dollars on your electric bill and taking only a minimal hit in the available heat content? Why let steam down and get no benefit from it, when putting it through a low pressure steam turbine coupled to a generator would produce the heat you need for process with the byproduct of onsite electrical generation. This paper analyzes the costs, concerns and benefits of replacing a pressure reducing valve with a Steam Turbine Generator set including illustrations of what the marginal fuel increase would be in order to take advantage of the added benefits of clean, cheap and reliable onsite power production.

Downing, A.

2012-01-01T23:59:59.000Z

290

Low energy ion beam assisted deposition of a spin valve  

Science Conference Proceedings (OSTI)

The spin dependent electron transport in giant magnetoresistive (GMR) multilayers is significantly affected by the atomic scale structure of their interfaces. Devices with atomically flat and chemically sharp interfaces are preferred for magnetic sensor and memory applications. Recent atomic simulations of the atom-by-atom assembly of these devices indicate that near optimal interfacial structures can be created using low energy, ion assisted vapor deposition techniques with ion energies in the 5-10 eV range. A recently developed biased target ion beam deposition system has been used to experimentally test this hypothesis. Prototypical Ta/NiFe/Co/Cu/Co/FeMn/Cu spin valve structures were first grown using (simultaneous) argon ion assistance during deposition of the Co/Cu/Co trilayer part of the spin valve multilayer. Assisting ion energies of around 10 eV resulted in structures with a 30% higher magnetoresistance ratio and significantly reduced coupling field compared to samples grown with no ion assistance or with ion energies above 15 eV. These results are consistent with the atomistic simulation predictions. Other promising ion assistance schemes identified by the simulations were then used to deposit the Ta, NiFe, FeMn, and the top copper layer. A near optimal strategy was identified that resulted in the further improvement of the GMR ratio.

Quan, J. J.; Wolf, S. A.; Wadley, H. N. G. [Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia 22903 (United States)

2007-04-01T23:59:59.000Z

291

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

292

Two-phase flow characteristics in multiple orifice valves  

SciTech Connect

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

293

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

Science Conference Proceedings (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

294

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

295

Hard X-ray Variability of AGN  

E-Print Network (OSTI)

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey are used to study the 14 - 195 keV variability of the 44 brightest AGN. The sources have been selected due to their detection significance of >10 sigma. We tested the variability using a maximum likelihood estimator and by analysing the structure function. Results: Probing different time scales, it appears that the absorbed AGN are more variable than the unabsorbed ones. The same applies for the comparison of Seyfert 2 and Seyfert 1 objects. As expected the blazars show stronger variability. 15% of the non-blazar AGN show variability of >20% compared to the average flux on time scales of 20 days, and 30% show at least 10% flux variation. All the non-blazar AGN which show strong variability are low-luminosity objects with L(14-195 keV) < 1E44 erg/sec. Conclusions: Concerning the variability pattern, there is a tendency of unabsorbed or type 1 galaxies being less variable than the absorbed or type 2 objects at hardest X-rays. A more solid anti-correlation is found between variability and luminosity, which has been previously observed in soft X-rays, in the UV, and in the optical domain.

V. Beckmann; S. D. Barthelmy; T. J. -L. Courvoisier; N. Gehrels; S. Soldi; J. Tueller; G. Wendt

2007-09-14T23:59:59.000Z

296

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

DOE Green Energy (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

297

Method of accounting for code safety valve setpoint drift in safety analyses  

Science Conference Proceedings (OSTI)

In performing the safety analyses for transients that result in a challenge to the reactor coolant system (RCS) pressure boundary, the general acceptance criterion is that the peak RCS pressure not exceed the American Society of Mechanical Engineers limit of 110% of the design pressure. Without crediting non-safety-grade pressure mitigating systems, protection from this limit is mainly provided by the primary and secondary code safety valves. In theory, the combination of relief capacity and setpoints for these valves is designed to provide this protection. Generally, banks of valves are set at varying setpoints staggered by 15- to 20-psid increments to minimize the number of valves that would open by an overpressure challenge. In practice, however, when these valves are removed and tested (typically during a refueling outage), setpoints are sometimes found to have drifted by >50 psid. This drift should be accounted for during the performance of the safety analysis. This paper describes analyses performed by Yankee Atomic Electric Company (YAEC) to account for setpoint drift in safety valves from testing. The results of these analyses are used to define safety valve operability or acceptance criteria.

Rousseau, K.R.; Bergeron, P.A.

1989-01-01T23:59:59.000Z

298

Passively operated spool valve for drain-down freeze protection of thermosyphon water heaters. Final technical report  

SciTech Connect

The work done to extend the existing drain-down valve technology to provide passive drain-down freeze protection for thermosyphon-based solar water heaters is described. The basic design of the existing valve model is that of a spool valve, employing a cylindrical spool which moves axially in a mating cartridge to open and close o-rings at the two operating extremes (drain and operate) to perform the valving function. Three passive actuators to drive the basic valving mechanism were designed, fabricated, and tested. Two piping configurations used to integrate the spool valve with the thermosyphon system are described, as are the passive actuators. The three actuator designs are: photovoltaic driven, refrigerant-based bellows, and heat motor cable-drive designs. Costs are compared for the alternative actuator designs, and operating characteristics were examined for the thermosyphon system, including field tests. The market for the valve for thermosyphon systems is then assessed. (LEW)

1982-04-30T23:59:59.000Z

299

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.

Richter, Tomas (State College, PA)

1998-01-01T23:59:59.000Z

300

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

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

Tropical Convective Variability as 1/f Noise  

Science Conference Proceedings (OSTI)

Evidence is presented that the tropical convective variability behaves as 1/f noise for a 130-day period. This behavior is shown by analyzing the time series of convective available potential energy, which measures the degree of convective ...

Jun-Ichi Yano; Klaus Fraedrich; Richard Blender

2001-09-01T23:59:59.000Z

302

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

DOE Green Energy (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

303

Proceedings of the symposium on inservice testing of pumps and valves  

Science Conference Proceedings (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

304

Endurance Tests of Valves With Cobalt-Free Hardfacing Alloys: BWR Phase Final Report  

Science Conference Proceedings (OSTI)

Valves hardfaced with three galling-resistant iron-base alloys (NOREM, EVERIT 50, and Deloro Stellite EB 5183) and a cobalt-base standard (Stellite 6) were subjected to stroke cycling in an environment simulating BWR chemistry conditions. Examination showed that the wear performance of valves with iron-base trim matched that of the cobalt-base standard. Yet, preferential corrosion of EB 5183 was found. Using cobalt-free alloys to replace or refurbish valves will significantly reduce released cobalt respo...

1993-03-01T23:59:59.000Z

305

Stochastic Forcing of Ocean Variability by the North Atlantic Oscillation  

Science Conference Proceedings (OSTI)

At middle and high latitudes, the magnitude of stochastic wind stress forcing of the ocean by atmospheric variability on synoptic time scales (i.e., weather related variability) is comparable to that of the seasonal cycle. Stochastic forcing ...

Kettyah C. Chhak; Andrew M. Moore; Ralph F. Milliff

2009-01-01T23:59:59.000Z

306

Modeling the Variability of Sydney Harbor Wind Measurements  

Science Conference Proceedings (OSTI)

The time-dependent behavior in the variability of wind measurements is investigated using bivariate generalized autoregressive conditional heteroscedastic models. These models express the current level of short-timescale wind variability in terms ...

Edward Cripps; William T. M. Dunsmuir

2003-08-01T23:59:59.000Z

307

A search for chaotic behavior in Northern Hemisphere stratospheric variability  

Science Conference Proceedings (OSTI)

Northern Hemisphere stratospheric variability is investigated with respect to chaotic behavior using time series from three different variables extracted from four different re-analysis products and two numerical model runs with different forcing. ...

Gualtiero Badin; Daniela I.V. Domeisen

308

Fail Save Shut Off Valve for Filtering Systems Employing Candle Filters  

NLE Websites -- All DOE Office Websites (Extended Search)

Fail Save Shut Off Fail Save Shut Off Valve for Filtering Systems Employing Candle Filters Opportunity The Department of Energy's National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implementing United States Patent Number 6,981,516 entitled "Fail save shut off valve for filtering systems employing candle filters." Disclosed in this patent is a novel fail save shut off valve system 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. It 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 fail save valve stops the flow

309

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

310

Dynamic simulation of heart mitral valve with transversely isotropic material model  

E-Print Network (OSTI)

This thesis develops two methods for simulating, in the finite element setting, the material behavior of heart mitral valve leaflet tissue. First, a mixed pressure-displacement formulation is used to implement the constitutive ...

Weinberg, Eli, 1979-

2005-01-01T23:59:59.000Z

311

Safety Evaluation Report, pump and valve inservice testing program, Maine Yankee Atomic Power Station  

Science Conference Proceedings (OSTI)

This EG and G, Inc., report presents the results of our evaluation of the Maine Yankee Atomic Power Station, Inservice Testing Program for pumps and valves whose function is important to safety.

Rockhold, H.C.; Stromberg, H.M.

1985-04-01T23:59:59.000Z

312

Electro-Hydraulic Servo-Valve and Motion and Control Loading of Full Flight Simulator.  

E-Print Network (OSTI)

??The present thesis is on the subject of electro-hydraulic servo-valve (EHV), and motion and control loading of a flight simulator with EHV. The fundamentals of (more)

Shi, Wei

2010-01-01T23:59:59.000Z

313

DOE specification: Valve-regulated type lead-acid storage batteries  

DOE Green Energy (OSTI)

This document contains a ``fill-in-the-blanks`` guide specification for procurement of sealed valve-regulated type lead-acid storage batteries, for uninterruptible power supply applications.

NONE

1996-08-01T23:59:59.000Z

314

Template for Submission of Risk-Informed Inservice Testing Program for Pumps and Valves  

Science Conference Proceedings (OSTI)

Nuclear power plants must update their inservice testing program for pumps and valves to the latest ASME code every ten years. This report provides a template for requesting an alternative to the technical requirements contained in that code.

1998-09-17T23:59:59.000Z

315

Giant magnetoresistance in ion beam deposited spin-valve films with specular enhancement  

Science Conference Proceedings (OSTI)

Three different techniques, natural oxidation, remote plasma oxidation and low energy ion beam oxidation, have been proved to be equally effective in forming nano-oxide layers (NOLs) in spin-valve films for specular enhancement of giant magnetoresistance (GMR) effect. GMR values over 12% have been routinely obtained in spin-valve films with NOL, corresponding to a 30% specular enhancement over those without NOL. The consistency and robustness of the oxidation processes has been demonstrated by a very large GMR value {similar_to}19% in a dual spin-valve film with the NOLs formed in both pinned layers, the oscillatory dependence of the interlayer coupling field on Cu layer thickness in specular enhanced spin-valve films and the uniform and repeatable film performance over 5 in. substrates. {copyright} 2001 American Institute of Physics.

Sant, S.; Mao, M.; Kools, J.; Koi, K.; Iwasaki, H.; Sahashi, M.

2001-06-01T23:59:59.000Z

316

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

SciTech Connect

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

317

Granular Attrition due to Rotary Valve in a Pneumatic Conveying System  

E-Print Network (OSTI)

The rotary valve is a widely used mechanical device in many solids-handling industrial processes. However, it may also be responsible for most of the attrition effects occurring in a typical process. In this study, the ...

Yao, Jun

318

Method and apparatus utilizing valve throttling and charge stratification in the operation of an internal combustion engine  

Science Conference Proceedings (OSTI)

In an internal combustion engine this patent describes means forming a combustion chamber, a spark plug in the chamber, a piston disposed in the chamber for reciprocable movement toward and away from the spark plug, a valve member, circular seat means for the valve member, means for varying the lift of the valve member, a generally cylindrical shroud corresponding generally to the size of the seat means. The cylindrical shroud is relieved only in the direction of the spark plug so that, when the valve member is moved relative to the shroud by the lift-varying means, a stratified mixture of air and fuel is directed toward the spark plug until the lift-varying means causes the valve member to pass beyond the shroud so that during the initial lift of the valve member the stratified air and fuel mixture is directed solely toward the spark plug until the valve member passes beyond the shroud and the air and fuel mixture is directed generally through a 360/sup 0/ arc after the valve member passes beyond the shroud, and means limiting the lift of the valve member so that it does not pass the shroud during lighter loads, whereby the air and fuel mixture is directed primarily toward the spark plug until the valve member passes beyond the shroud.

Burandt, C.O.

1988-02-16T23:59:59.000Z

319

Nanostructured Coatings for Improved Erosion Resistance of Valve Stem Materials 2013 Field Test Trials Update  

Science Conference Proceedings (OSTI)

The Electric Power Research Institute- (EPRI-) developed nanostructured coatings (nanocoatings), deposited by plasma- enhanced magnetron sputtering, show great promise for improved erosion and wear resistance in many power plant applications. EPRI laboratory research in 2010 developed the processing to apply these coatings over nitrided/malcomized (hardened) steam turbine valve stems, which is described in EPRI report 1019796, Application of Nanocoatings for Erosion Protection of Valve ...

2013-12-20T23:59:59.000Z

320

AECL Qualification of Greases for Motor-Operated Valve Stem/Stem Nut Lubrication  

Science Conference Proceedings (OSTI)

The frictional characteristics of lubricants used in the actuators of motor-operated valves are critical to ensuring adequate actuator output capability. As part of the EPRI Motor-Operated Valve (MOV) Performance Prediction Program, testing was conducted at ambient temperature conditions on over 20 stem-stem nut lubricants in use in United States nuclear plants as documented in EPRI report TR-103235. Additional research has been conducted on several MOV lubricants after thermal and radiation aging under ...

1998-11-24T23:59:59.000Z

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.


321

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  

DOE Green Energy (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

322

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

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

323

VARIABLE CHARGE MOTION FOR 2007-2010 DIESEL ENGINES  

DOE Green Energy (OSTI)

The use of direct injection diesel engines in US heavy duty pickup truck applications is becoming increasingly popular with over 250,000 produced in 2002. The high torque density and greatly improved fuel consumption offer distinct advantages to the end user. 2007 and 2010 emissions legislation will present another set of technical and product cost challenges to this type of powertrain. The introduction of efficient aftertreatment systems is mandatory to the success of these engines but optimization of engine-out emissions is also a critical element. Much has been written on the improvements in modern fuel systems which offer great flexibility for the direct introduction of fuel into the cylinder. This paper presents complementary technologies which allow improved air/fuel mixing processes by the additional flexibility of variable in-cylinder charge motion. This approach is particularly applicable to pick-up truck engines, which require high BMEP levels across a wide engine speed range to offer the driveability demanded by the consumer. Design solutions for 2 valve and 4 valve engines are presented along with the potential emissions and fuel consumption benefits.

Maier, J

2003-08-24T23:59:59.000Z

324

Estimated Global Hydrographic Variability  

Science Conference Proceedings (OSTI)

An estimate is made of the three-dimensional global oceanic temperature and salinity variability, omitting the seasonal cycle, both as a major descriptive element of the ocean circulation and for use in the error estimates of state estimation. ...

Gal Forget; Carl Wunsch

2007-08-01T23:59:59.000Z

325

Understanding Biomass Feedstock Variability  

SciTech Connect

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

326

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

327

Bond Graph Modeling Of Variable Structure Systems  

E-Print Network (OSTI)

The problem of describing variable structure models in a compact, object--oriented fashion is revisited and analyzed from the perspective of bond graph modeling. Traditionally, bond graphs have always been used to describe continuous-- time physical processes with a fixed structure. Yet, this paper shall demonstrate that bond graphs are equally suitable to describe variable structure models as fixed structure models. Moreover, a bond graph description of variable structure models can teach us a lot about the essential properties of variable structure models, properties that are not easily visible when other modeling approaches are taken. The paper discusses issues related to causality reassignment and conditional index changes as a consequence of switching in a physical system. Keywords: Bond graphs, variable structure system, computational causality, conditional index change, switching, object--oriented modeling, Dymola. INTRODUCTION When the causality strokes were added to the forme...

Franois E. Cellier; Martin Otter; Hilding Elmqvist

1995-01-01T23:59:59.000Z

328

Nuclear Maintenance Applications Center: Application Guide for Motor-Operated Valves in Nuclear Power Plants - Revision 2  

Science Conference Proceedings (OSTI)

Motor-operated gate and globe valves are widely used in both safety-related and non-safety-related systems in nuclear power plants. Their proper operation is essential for reliable plant performance and can help eliminate costly downtime. This second revision of the Application Guide for Motor-Operated Valves provides the latest in methods for conducting engineering evaluations in order to confirm that motor-operated gate, globe, and butterfly valves will perform their required function and offers sugges...

2007-08-22T23:59:59.000Z

329

Acceptance test report for the AN valve pit leak detection and low point drain assembly mock up test procedure  

SciTech Connect

This document describes The Performance Mock-up Test Procedure for the Valve Pit Leak Detection and Low Point Drain Assembly Performance Mock-Up Test Procedure.

EWER, K.L.

1999-07-20T23:59:59.000Z

330

Heart valve cardiomyocytes of mouse embryos express the serotonin transporter SERT  

SciTech Connect

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

331

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

SciTech Connect

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

332

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. 28 figs.

Lyon, R.H.; Chai, J.; Lang, J.H.; Hagman, W.H.; Umans, S.D.; Saarela, O.J.

1997-01-14T23:59:59.000Z

333

Modeling 18 Water Variability  

Science Conference Proceedings (OSTI)

Variability of 18 Water formation is investigated with an isopycnic-coordinate model of the North Atlantic. A 30-year spinup integration is used as a control experiment in which the upper water column in the Sargasso Sea is shown to be in ...

Robert Marsh; Adrian L. New

1996-06-01T23:59:59.000Z

334

Variable effect desorber-resorber absorption cycle  

DOE Patents (OSTI)

An absorption refrigeration system has an intermediate temperature desorber-resorber pair. A valve between the desorber-resorber pair is modulated to control the capacity for load matching.

Biermann, Wendell J. (Fayetteville, NY)

1985-01-01T23:59:59.000Z

335

English-Spanish glossary: offshore exploration and production, gas processing, and valves  

Science Conference Proceedings (OSTI)

This series of articles contains 3 different English-Spanish glossaries of related terms used in the oil industry. The glossary of the offshore exploration and production involves a summary of terms used in the offshore oil activity. It also includes names of singular equipment used in offshore drilling, as well as several navigation terms in relation to the floating oil structures. With the help of the Gas Processors Association it was possible to compile a glossary of gas processing with a concise selection of common terms of the industry of gas processing. The glossary of valves includes more than 200 terms of the industry of valves in a specialized glossary, and several explanations about the application and operation of valves.

Not Available

1981-12-01T23:59:59.000Z

336

Failure analyses of two ball valves used for coal-gasification applications  

SciTech Connect

Two ball valves which had failed by developing excess leakage were supplied for analyses. The 2'' (51 mm) valve had experienced 5000 cycles during 20 hrs usage in an unknown chemical environment. Wear on the ball and seats was a multi-stage process starting with breakdown of a hard chrome plating on the stainless steel ball. This eventually led to adhesive weld transfer of the stainless steel to the seat made of Stellite 6 alloy. The 6'' (152 mm) ball valve had experienced a cycling test sequence using compressed air up to 300 psig (2.07 MPa) at 850/sup 0/F (727/sup 0/K). Damage was characterized as abrasive wear caused either by particles deposited by the compressed air or by carbide particles present in the Stellite 6 alloy ball and seat hardfacing. The decrease in this alloy's compressive yield strength at the elevated test temperature contributed to increased wear rates.

Van Den Avyle, J.A.; Pope, L.E.

1982-07-01T23:59:59.000Z

337

Whitey Swagelok SCHe ball valves Provide Isolation between SCHe Purge Lines C and D and the Process Vent  

Science Conference Proceedings (OSTI)

These valves are 1/4 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They provide an isolation function betwen SCHe Purge Line C, (PV-V-*079), and Purge Line D, (PV-V-*080), and the Process Vent.

MISKA, C.R.

2000-09-03T23:59:59.000Z

338

Energy-Saving Control of Single-Rod Hydraulic Cylinders with Programmable Valves and Improved Working Mode Selection  

E-Print Network (OSTI)

tremendous flexibility to control the cylinder motion while decreasing the energy usage by utilizing and individual cylinder chamber pressure control for better energy saving. With a typical four-way directional energy usage. The programmable valve configuration used in this study is seen in Figure 1. Cylinder Valve

Yao, Bin

339

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

340

Variable percentage sampler  

DOE Patents (OSTI)

A remotely operable sampler is provided for obtaining variable percentage samples of nuclear fuel particles and the like for analyses. The sampler has a rotating cup for a sample collection chamber designed so that the effective size of the sample inlet opening to the cup varies with rotational speed. Samples of a desired size are withdrawn from a flowing stream of particles without a deterrent to the flow of remaining particles.

Miller, Jr., William H. (Knoxville, TN)

1976-01-01T23:59:59.000Z

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.


341

Variable laser attenuator  

DOE Patents (OSTI)

The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

342

Variable laser attenuator  

SciTech Connect

The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

Foltyn, Stephen R. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

343

Solar-type Variables  

E-Print Network (OSTI)

The rich acoustic oscillation spectrum in solar-type variables make these stars particularly interesting for studying fluid-dynamical aspects of the stellar interior. I present a summary of the properties of solar-like oscillations, how they are excited and damped and discuss some of the recent progress in using asteroseismic diagnostic techniques for analysing low-degree acoustic modes. Also the effects of stellar-cycle variations in low-mass main-sequence stars are addressed.

Houdek, Gunter

2009-01-01T23:59:59.000Z

344

Errors in all variables  

SciTech Connect

We present a thorough derivation of the posterior for the straight line fit employing the hyper-plane prior. For the example of the parabola we enlarge the scope to nonlinear problems, however simplify it to be solved resembling the straight line solution. Finally we come to the problem of determining the exponents of a scaling law, where in logarithmic form the scaling exponents are linear coefficients of logarithmic variables.

Preuss, R.; Dose, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2005-11-23T23:59:59.000Z

345

The Coordinated Control of a Central Air Conditioning System Based on Variable Chilled Water Temperature and Variable Chilled Water Flow  

E-Print Network (OSTI)

At present, regulation of water flow by means of pump frequency conversion is one of the major methods for power-saving in central air conditioning systems. In this article, optimization regulation for central air conditioning system on the basis of coordinative optimization control for variable chilled water temperature and variable chilled water flow to obtain better power savings is put forward. According to typical meteorological year data, hourly air conditioning load of whole year for every typical room has been calculated with the transmission function method. In order to guarantee each typical room, the highest cooling load rate is used as an input parameter for optimization calculation. Based on the surface cooler check model, the smallest energy consumption of chiller and chiller water pump was taken as the objective function of the optimization model. The performance characteristics of a chiller, water pump, regulation valve and pipeline are taken into account, and the optimization chilled water temperature and chilled water flow were carried out. The case study for a commercial building in Guangzhou showed that the annual power consumption of the chillers and pumps of the air conditioning system is lower by 17% only with employment of variable water flow regulation by pump frequency conversion. In the case of optimization control with coordinative control of variable chilled water temperature and variable chilled water flow, the annual power consumption of the chillers and pumps of the air conditioning system is reduced by 22% in presence of remarkable power saving effects. Increasing the chilled water temperature will reduce the dehumidified capability of the air cooler, and the indoor relative humidity will increase. The simulation showed that the adjustment optimized process meets the comfort of each typical room. The lower the cooling load rate is, the more obvious the effect of power-saving is. The highest power-saving rate appears in December, which is 36.7%. Meanwhile, the least rate appears in July, which is only 14.5%.

Liu, J.; Mai, Y.; Liu, X.

2006-01-01T23:59:59.000Z

346

Variable Stars in the Globular Cluster NGC 4590 (M68  

E-Print Network (OSTI)

We present results of time series photometry to search for variable stars in the field of metal-poor globular cluster NGC 4590 (M68). Periods have been revised for 40 known variables and no significant changes were found. A considerable change in Blazhko effect for V25 has been detected. Among nine newly discovered variable candidates, 5 stars are of RRc Bailey type variables while 4 stars are unclassified. The variable stars V10, V21, V50 and V51 are found to be cluster members based on the radial velocity data taken from literature.

Sariya, Devesh Path; Yadav, R K S

2013-01-01T23:59:59.000Z

347

Reuse and variability in large software applications  

Science Conference Proceedings (OSTI)

Reuse has always been a major goal in software engineering, since it promises large gains in productivity, quality and time to market reduction. Practical experience has shown that substantial reuse has only successfully happened in two cases: libraries, ... Keywords: AOP, COTS, EAI, MDA, interoperability, model driven software engineering, process driven application, product families, product line, reuse, variability, workflow

Jacky Estublier; German Vega

2005-09-01T23:59:59.000Z

348

Investigation of determinism in heart rate variability  

Science Conference Proceedings (OSTI)

The article searches for the possible presence of determinism in heart rate variability (HRV) signals by using a new approach based on NARMA (nonlinear autoregressive moving average) modeling and free-run prediction. Thirty-three 256-point HRV time series obtained from Wistar rats submitted to different autonomic blockade protocols are considered

M. E. D. Gomes; A. V. P. Souza; H. N. Guimares; L. A. Aguirre

2000-01-01T23:59:59.000Z

349

Numerical analysis of the heat transfer for packing design of cryogenic gate valve  

Science Conference Proceedings (OSTI)

The packing, among the components comprising the gate valve, is used to sustain the airtightness and the study on change of shape or pattern has been carried out to maximize the functions, but the study on changing the location or the size of the packing ... Keywords: cryogenic, heat transfer, liquefied natural gas, numerical analysis, packing

Si Pom Kim; Rock Won Jeon; Il Ju Hwang; Jae Hoon Lee; Won Heaop Shin

2012-04-01T23:59:59.000Z

350

Analysis on Modulation Principle of Mechanical Spring Valve Block-Type Pulse Jet  

Science Conference Proceedings (OSTI)

To take full advantage of the bottom-hole hydraulic energy to improve the drilling rate, it is proposed the technique assumption that using mechanical spring valve periodically is to block the fluid pathway, and modulating pulse jet is to increase the ... Keywords: block type, pulse jet, drilling rate, water hammer, experimental study

Ni Hongjian; Zhu Lihong; Huo Hongjun; Tang Zhiwen

2011-08-01T23:59:59.000Z

351

New electromagnetic methods for the evaluation of prosthetic heart valves (invited)  

Science Conference Proceedings (OSTI)

Prosthetic devices are being implanted at record levels as the nation ages and advances in prosthetic science are made. Devices that are implanted range from artificial limbs and hips to devices such as heart valves. Periodic evaluation of the state of the devices is of significant interest particularly in the case of prosthetics whose failure can be fatal. An example of such a device is the artificial heart valve. Heart valves are usually replaced when stenosis or incompetence is indicated. This article presents a selection of some new techniques that are being developed for the detection of outlet strut failures in Bjork-Shiley heart valves. Methods that show particular promise include a noninvasive electromagnetic method that relies on the excitation and measurement of the resonant vibration modes of the strut. An alternate approach involves the induction of currents in the outlet strut using a pair of external excitation coils. The field generated by the current induced in the strut perturbs the field generated by the excitation coils. The field perturbations are measured using a catheter-mounted gradiometer. Test results obtained using an experimental rig designed to demonstrate the proof-of-concept are presented.

Satish Udpa

2002-01-01T23:59:59.000Z

352

Mathematical Modeling of Current-Interrupt and Pulse Operation of Valve-Regulated Lead Acid Cells  

E-Print Network (OSTI)

are resolved. Of the two candidate battery systems, the low cost and ease of operation of the VRLA battery the last decade, advanced batteries have re- ceived much attention. At present, only the valve-regulated lead acid VRLA and the nickel-metal hydride Ni-MH battery are being actively considered

353

A valve with seat?slope proportional to flow area at all poppet positions  

Science Conference Proceedings (OSTI)

An adjustable gas?blending apparatus is hypothesized that would maintain a consistent mixture over a broad range of flowrates. The design equations for the unique valve seat required for such an apparatus are developed and solved numerically. An example seat is calculated and illustrated in table form. For preliminary study

D. W. Guillaume; D. DeVries

1991-01-01T23:59:59.000Z

354

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

DOE Green Energy (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

355

Endurance tests of valves with cobalt-free hardfacing alloys: PWR phase  

SciTech Connect

Atomic Energy of Canada Limited (AECL) is conducting endurance tests on valves hard-faced with four cobalt-free alloys. The first phase of the program, in which PWR primary heat transport conditions were simulated in AECL's valve test loop, has been completed. The candidate alloys are NOREM 01, NOREM 04, EB 5183 and EVERIT 50. One valve with Stellite 6 trim served as the standard. Prior to loop testing, a baseline inaugural inspection was performed. During testing the loop was shutdown at approximately 500 cycle intervals, and the valves were disassembled for examination. The examinations included seat leak tests, profilometry, nondestructive inspection and finally destructive examination. Corrosion coupons in the loop were used to monitor any material loss due solely to corrosion mechanisms. This report summarizes the final examination results and discusses the relative performance of the candidate alloys. The results indicate that, based upon the sliding wear damage assessment and seat leakage test results, all the candidate alloys perform better than the Stellite 6 control sample. On the same basis, NOREM 04 and EB 5183 are the best of the candidate alloys, although there are only minor differences in performance among the four alloys.

Murphy, E.V.; Inglis, I. (Atomic Energy of Canada Ltd., Mississauga, ON (Canada))

1992-05-01T23:59:59.000Z

356

Temperature impacts on the set pressure of soft seated pressure relief valves  

SciTech Connect

From a safety standpoint, regardless of plant or facility type, the most important pieces of equipment are the pressure relief devices. The most critical characteristics of a pressure relief device are its set pressure and the related relieving capacity. The Set Pressure of a pressure relief device is defined as that value of increasing inlet static pressure at which the discharge becomes continuous (ASME PTC 25-1994, Performance Test Codes). To preclude an unsafe overpressure situation, the set pressure of the pressure relief device must not exceed the maximum allowable working pressure of the equipment or system being protected. Because of testing facility limitations, size or pressure, pressure relief valves intended for elevated temperature service are often set using ambient temperature air. Adjustments are made to the ambient valve opening pressures to compensate for the temperature differences. The extent of the adjustments to the pressure relief valve set pressure is important to ensure the valve will provide the required overpressure protection at the elevated in-service temperature.

Engel, J.J.; Zirps, G.T.; Gleason, R.B. [and others

1995-11-01T23:59:59.000Z

357

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

E-Print Network (OSTI)

to the valve and increases radiation exposure of operators, leading to long overhaul outage and high techniques rely on the measurement of an internal mechanical quantity and require the presence of human of any internal MOV quantity. In this article, the instantaneous active power absorbed by the induction

Paris-Sud XI, Université de

358

Technical Repair Guidelines for Limitorque Models SMB 0 Through 4 Valve Actuators  

Science Conference Proceedings (OSTI)

This technical repair guide for Limitorque motor-operated valve (MOV) actuator models SMB 0 through 4 represents the third in a series of documents devoted to the comprehensive maintenance and repair of Limitorque actuators. This guide provides instructions for engineering, operations, and maintenance personnel on MOV actuator repair, maintenance, adjustment, and troubleshooting methods.

1993-02-28T23:59:59.000Z

359

Time and Space Variability of Tropical Pacific Wind Stress  

Science Conference Proceedings (OSTI)

The results of a spectral analysis of a new, subjectively analyzed data set of tropical Pacific wind stress are presented. The monthly data for the 10-year period, 196170, allow a detailed inspection of the distributions of frequency and zonal ...

Stanley B. Goldenberg; James J. O'Brien

1981-06-01T23:59:59.000Z

360

Microstructural Variables Controlling Time-Dependent Crack Growth ...  

Science Conference Proceedings (OSTI)

Quantitative image analysis was performed to analyze the microstructural features produced by ..... scenario provided that it can be shown that the precipitate.

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

Bayesian Variable Selection for Nowcasting Economic Time Series  

E-Print Network (OSTI)

motivation Want to use Google Trends data to nowcast economic series unemployment may be predicted by "job;Avoid spurious regression How to control for trend and seasonality? Build a model for the predictable-chosen contemporaneous regressors from Google Trends non-seasonal AR1: yt = a1yt-1 + bxt + et seasonal AR1: yt = a1yt-1

Varian, Hal R.

362

Time and Space Variability of Spectral Estimates of Atmospheric Pressure  

Science Conference Proceedings (OSTI)

The purpose of this paper is to analyze the temporal and spatial behavior of atmospheric pressure spectra. The literature shows many examples of pressure, wind and temperature spectra whose shapes display a remarkable degree of universality. ...

Flavio G. Canavero; Franco Einaudi

1987-06-01T23:59:59.000Z

363

Rapid Oscillations in Cataclysmic Variables  

E-Print Network (OSTI)

I give an overview of the rich phenomenology of dwarf nova oscillations (DNOs) and Quasi-periodic Oscillations (QPOs) observed in cataclysmic variable stars (CVs). The favoured interpretation of these rapid brightness modulations (3 - >1000 s time scales) is that they are magnetic in nature - magnetically channelled accretion from the inner accretion disc for DNOs and possible magnetically excited travelling waves in the disc for QPOs. There is increasing evidence for the magnetic aspects, which extend to lower field the well known properties of strong field (polars) and intermediate strength field (intermediate polars) CVs. The result is that almost all CVs show the presence of magnetic fields on their white dwarf primaries - though for many the intrinsic field may be locally enhanced by the accretion process itself. There are many parallel behaviours with the QPOs seen in X-Ray binaries, with high and low frequency X-Ray QPOs resembling respectively the DNOs and QPOs in CVs.

Brian Warner

2003-12-06T23:59:59.000Z

364

Jets with Variable R  

E-Print Network (OSTI)

We introduce a new class of jet algorithms designed to return conical jets with a variable Delta R radius. A specific example, in which Delta R scales as 1/pT, proves particularly useful in capturing the kinematic features of a wide variety of hard scattering processes. We implement this Delta R scaling in a sequential recombination algorithm and test it by reconstructing resonance masses and kinematic endpoints. These test cases show 10-20% improvements in signal efficiency compared to fixed Delta R algorithms. We also comment on cuts useful in reducing continuum jet backgrounds.

David Krohn; Jesse Thaler; Lian-Tao Wang

2009-03-02T23:59:59.000Z

365

A characterization of check valve degradation and failure experience in the nuclear power industry: 1984-1990. Volume 1  

SciTech Connect

Check valve operating problems in recent years have resulted in significant operating transients, increased cost and decreased system availability. As a result, additional attention has beau given to check valves by utilities (resulting in the formation of the Nuclear Industry Check Valve Group), as well as the US Nuclear Regulatory Commission and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. 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. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are considered, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions.

Casada, D.A.; Todd, M.D. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States)

1993-09-01T23:59:59.000Z

366

Solar Irradiance Variability  

E-Print Network (OSTI)

The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation and the solar cycle. A part of the difficulty is that there are no other constant natural daytime sources to which the Sun's brightness can be compared. The discovery of solar irradiance variability rekindled a long-running discussion on how strongly the Sun affects our climate. A non-negligible influence is suggested by correlation studies between solar variability and climate indicators. The mechanism for solar irradiance variations that fits the observations best is that magnetic features at the solar surface, i.e. sunspots, faculae and the magnetic network, are responsible for almost all variations (although on short timescales convection and p-mode oscillations also contribute). In spite of significant progress important questions are still open. Thus there is a debat...

Solanki, Sami K

2012-01-01T23:59:59.000Z

367

CHARACTERIZING THE OPTICAL VARIABILITY OF BRIGHT BLAZARS: VARIABILITY-BASED SELECTION OF FERMI ACTIVE GALACTIC NUCLEI  

SciTech Connect

We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the {approx}30% of {gamma}-ray sources in the Fermi 2FGL catalog still lacking reliable associations. Using data from the optical LINEAR asteroid survey, we characterize the optical variability of blazars by fitting a damped random walk model to individual light curves with two main model parameters, the characteristic timescales of variability {tau}, and driving amplitudes on short timescales {sigma}-circumflex. Imposing cuts on minimum {tau} and {sigma}-circumflex allows for blazar selection with high efficiency E and completeness C. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of {gamma}-ray sources in the Fermi 2FGL catalog. Despite the extreme stellar contamination at the shallow depth of the LINEAR survey, we are able to recover previously associated optical counterparts to Fermi active galactic nuclei with E {>=} 88% and C = 88% in Fermi 95% confidence error ellipses having semimajor axis r < 8'. We find that the suggested radio counterpart to Fermi source 2FGL J1649.6+5238 has optical variability consistent with other {gamma}-ray blazars and is likely to be the {gamma}-ray source. Our results suggest that the variability of the non-thermal jet emission in blazars is stochastic in nature, with unique variability properties due to the effects of relativistic beaming. After correcting for beaming, we estimate that the characteristic timescale of blazar variability is {approx}3 years in the rest frame of the jet, in contrast with the {approx}320 day disk flux timescale observed in quasars. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.

Ruan, John J.; Anderson, Scott F.; MacLeod, Chelsea L.; Becker, Andrew C.; Davenport, James R. A.; Ivezic, Zeljko [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Burnett, T. H. [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States); Kochanek, Christopher S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Plotkin, Richard M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Stuart, J. Scott, E-mail: jruan@astro.washington.edu [Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, MA 02420-9108 (United States)

2012-11-20T23:59:59.000Z

368

Logarithmic time parallel Bayesian inference  

Science Conference Proceedings (OSTI)

I present a parallel algorithm for exact probabilistic inference in Bayesian networks. For polytree networks with n variables, the worstcase time complexity is O(logn) on a CREW PRAM (concurrent-read, exclusive-write parallel random-access ...

David M. Pennock

1998-07-01T23:59:59.000Z

369

Climate Variability, Fish, and Fisheries  

Science Conference Proceedings (OSTI)

Fish population variability and fisheries activities are closely linked to weather and climate dynamics. While weather at sea directly affects fishing, environmental variability determines the distribution, migration, and abundance of fish. ...

P. Lehodey; J. Alheit; M. Barange; T. Baumgartner; G. Beaugrand; K. Drinkwater; J.-M. Fromentin; S. R. Hare; G. Ottersen; R. I. Perry; C. Roy; C. D. van der Lingen; F. Werner

2006-10-01T23:59:59.000Z

370

Colorado River Basin Hydroclimatic Variability  

Science Conference Proceedings (OSTI)

An analysis of annual hydroclimatic variability in the Upper Colorado River basin (UCRB) for the period of 19062006 was performed to understand the dominant modes of multidecadal variability. First, wavelet-based spectral analysis was employed ...

Kenneth Nowak; Martin Hoerling; Balaji Rajagopalan; Edith Zagona

2012-06-01T23:59:59.000Z

371

Scalable analysis of variable software  

Science Conference Proceedings (OSTI)

The advent of variability management and generator technology enables users to derive individual variants from a variable code base based on a selection of desired configuration options. This approach gives rise to the generation of possibly billions ... Keywords: C Preprocessor, Liveness Analysis, Software Product Lines, Type Checking, Variability-aware Analysis

Jrg Liebig; Alexander von Rhein; Christian Kstner; Sven Apel; Jens Drre; Christian Lengauer

2013-08-01T23:59:59.000Z

372

Variability within Modeling Language Definitions  

Science Conference Proceedings (OSTI)

We present a taxonomy of the variability mechanisms offered by modeling languages. The definition of a formal language encompasses a syntax and a semantic domain as well as the mapping that relates them, thus language variabilities are classified according ... Keywords: Modeling languages, UML, formal semantics, variability

Mara Victoria Cengarle; Hans Grnniger; Bernhard Rumpe

2009-10-01T23:59:59.000Z

373

Symmetrization Of Binary Random Variables  

E-Print Network (OSTI)

A random variable Y is called an independent symmetrizer of a given random variable X if (a) it is independent of X and (b) the distribution of X Y is symmetric about 0. In cases where the distribution of X is symmetric about its mean, it is easy to see that the constant random variable Y is a minimum-variance independent symmetrizer. Taking

Abram Kagan; Colin Mallows; Larry Shepp; Robert J. Vanderbei; Yehuda Vardi

1999-01-01T23:59:59.000Z

374

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

DOE Green Energy (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

375

Simulation of Atmospheric Variability  

Science Conference Proceedings (OSTI)

A spectral atmospheric circulation model is time-integrated for approximately 18 years. The model has a global computational domain and realistic geography and topography. The model undergoes an annual cycle as daily values of seasonally varying ...

Syukuro Manabe; Douglas G. Hahn

1981-11-01T23:59:59.000Z

376

Dirac equation in terms of hydrodynamic variables  

E-Print Network (OSTI)

The distributed system $\\mathcal{S}_D$ described by the Dirac equation is investigated simply as a dynamic system, i.e. without usage of quantum principles. The Dirac equation is described in terms of hydrodynamic variables: 4-flux $j^{i}$, pseudo-vector of the spin $S^{i}$, an action $\\hbar \\phi $ and a pseudo-scalar $\\kappa $. In the quasi-uniform approximation, when all transversal derivatives (orthogonal to the flux vector $j^i$) are small, the system $\\mathcal{S}_D$ turns to a statistical ensemble of classical concentrated systems $\\mathcal{S}_{dc}$. Under some conditions the classical system $\\mathcal{S}_{dc}$ describes a classical pointlike particle moving in a given electromagnetic field. In general, the world line of the particle is a helix, even if the electromagnetic field is absent. Both dynamic systems $\\mathcal{S}_D$ and $\\mathcal{S}_{dc}$ appear to be non-relativistic in the sense that the dynamic equations written in terms of hydrodynamic variables are not relativistically covariant with respect to them, although all dynamic variables are tensors or pseudo-tensors. They becomes relativistically covariant only after addition of a constant unit timelike vector $f^{i}$ which should be considered as a dynamic variable describing a space-time property. This "constant" variable arises instead of $\\gamma $-matrices which are removed by means of zero divizors in the course of the transformation to hydrodynamic variables. It is possible to separate out dynamic variables $\\kappa $, $\\kappa ^i$ responsible for quantum effects. It means that, setting $\\kappa ,\\kappa ^i\\equiv 0$, the dynamic system $\\mathcal{S}_D$ described by the Dirac equation turns to a statistical ensemble $\\mathcal{E}_{Dqu}$ of classical dynamic systems $\\mathcal{S}_{dc}$.

Yuri A. Rylov

2011-01-31T23:59:59.000Z

377

Minimising the delta test for variable selection in regression problems  

Science Conference Proceedings (OSTI)

The problem of selecting an adequate set of variables from a given data set of a sampled function becomes crucial by the time of designing the model that will approximate it. Several approaches have been presented in the literature although recent studies ... Keywords: FBS, GAs, delta test, forward-backward search, genetic algorithms, hybrid algorithms, parallel architectures, regression problems, tabu search, variable selection

Alberto Guillen; Dusan Sovilj; Amaury Lendasse; Fernando Mateo; Ignacio Rojas

2008-03-01T23:59:59.000Z

378

Problems of Cosmological Variability of Fundamental Physical Constants  

E-Print Network (OSTI)

of the fundamental constants which govern most of the common phenomena and are usually given in the handbooks. NoteProblems of Cosmological Variability of Fundamental Physical Constants #3; D. A. Varshalovich, A. Y and astronomical observations aimed at testing the possible space-time variability of fundamental physical

379

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

SciTech Connect

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

380

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

SciTech Connect

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.

2002-01-01T23:59:59.000Z

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.


381

Light absorption cell combining variable path and length pump  

DOE Patents (OSTI)

This invention is comprised of 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, W.S.

1992-12-31T23:59:59.000Z

382

Post-Remedial Action Report the Chapman Valve Site E I P I I  

Office of Legacy Management (LM)

for for Post-Remedial Action Report the Chapman Valve Site E I P I I I t I 1 I I I 1 I li I I Pnnted on recycledkecyclable paper 24 19 0186 1 DOE/OW21949-408 Formerly Utilized Sites Remed Contr: al Action Program (FUSRAP) L C t NO. DE-AC05-91 OR21 949 Indian Orchard, assac h.usetts November 1996 DOE/OR/2 1949-408 POST-REMEDIAL ACTION REPORT FOR THE CHAPMAN VALVE SITE INDIAN ORCHARD, MASSACHUSETTS NOVEMBER 1996 Prepared for United States Department of Energy Oak Ridge Operations Office Under Contract No. DE-AC05-91 OR2 1949 Bechtel National, Inc. Oak Ridge, Tennessee . . Bechtel Job No. 14501 CONTENTS Page . FIGURES ................................................................................... 1 .............................................................. iv

383

Valve Packing Performance Improvement: Sealing Technology and Plant Leakage Reduction Series  

Science Conference Proceedings (OSTI)

"Valve Packing Performance Improvement" is the seventh in a series of training modules addressing leakage at nuclear power plants. The first six modules in this series address: o Leakage management programs o Assembling bolted joints with spiral-wound gaskets o Preload requirements for bolted joints with spiral-wound gaskets o Lube oil system leakage mitigation o Leakage reduction from threaded joints o Leakage reduction from bolted joints with sheet gaskets

2002-03-28T23:59:59.000Z

384

Use of MCC-Based Motor Torque Measurements for Periodic Verification of Motor-Operated Valves  

Science Conference Proceedings (OSTI)

This report develops, justifies, and validates a motor control center- (MCC-) based motor torque periodic verification (MTPV) method for torque-switch-controlled closing strokes of rising stem motor-operated valves (MOVs) with ac motors. The report details the evaluation of motor torque data obtained from electrical measurements at the MCC and covers the use of these (and other) measurements in MOV periodic verification (PV) testing.

2006-03-30T23:59:59.000Z

385

Nuclear Maintenance Applications Center: Air-Operated Valve Maintenance Guide: Revision 2  

Science Conference Proceedings (OSTI)

An increased awareness of the importance of air-operated valves (AOVs) has led to progressively more sophisticated maintenance practices within the nuclear industry. Nonnuclear plants are also heavily dependent on reliable AOV operation. The dynamic method used by fossil power plants to satisfy transient electrical demands places additional stress on plant components, including AOVs. Therefore, there is a growing need for standardized technical guidance related to AOVs. The Electric Power Research Instit...

2008-12-18T23:59:59.000Z

386

Valve-Regulated Lead Acid (VRLA) Battery Seismic Testing: Initial Investigation  

Science Conference Proceedings (OSTI)

This report describes the results obtained when subjecting naturally aged valve-regulated lead acid (VRLA) batteries from two manufacturers to the capacity test, seismic test, and final capacity test described in IEEE Standard 535- 2006, Standard for Qualification of Class 1E Lead Storage Batteries for Nuclear Power Generating Stations. The project that is the subject of this report was not intended to be a formal qualification program or process. Instead, it was a test of the seismic ruggedness of ...

2013-04-12T23:59:59.000Z

387

Technical Repair Guidelines for Limitorque Model SMB-000 Valve Actuators: Revision 1  

Science Conference Proceedings (OSTI)

This technical repair guide (TRG) for Limitorque motor-operated valve (MOV) actuator model SMB-000 is the first in a series of documents devoted to the comprehensive maintenance and repair of Limitorque actuators. This guide provides instructions for engineering, operations, and maintenance personnel on MOV actuator repair, maintenance, adjustment, and troubleshooting methods. Originally published in 1989, this document has now been thoroughly revised (Revision 1) to incorporate new information and techn...

1994-10-02T23:59:59.000Z

388

Global Characteristics of Stream Flow Seasonality and Variability  

Science Conference Proceedings (OSTI)

Monthly stream flow series from 1345 sites around the world are used to characterize geographic differences in the seasonality and year-to-year variability of stream flow. Stream flow seasonality varies regionally, depending on the timing of ...

Michael D. Dettinger; Henry F. Diaz

2000-08-01T23:59:59.000Z

389

Pacific Decadal Variability: Paced by Rossby Basin Modes?  

Science Conference Proceedings (OSTI)

A systematic study is presented of decadal climate variability in the North Pacific. In particular, the hypothesis is addressed that oceanic Rossby basin modes are responsible for enhanced energy at decadal and bidecadal time scales. To this end, ...

Wilbert Weijer; Ernesto Muoz; Niklas Schneider; Franois Primeau

2013-02-01T23:59:59.000Z

390

Biennial Variability in an Atmospheric General Circulation Model  

Science Conference Proceedings (OSTI)

Recent observational analyses have indicated that tropospheric quasi-biennial oscillations (QBs) may play a fundamental role in regulating the timing and strength of El Nio and the Southern Oscillation. The biennial variability is examined in ...

Michael A. Alexander; Klaus M. Weickmann

1995-03-01T23:59:59.000Z

391

Decadal Climate Variability: Is There a Tidal Connection?  

Science Conference Proceedings (OSTI)

A possible connection between oceanic tides and climate variability arises from modulations in tidally induced vertical mixing. The idea is reexamined here with emphasis on near-decadal time scales. Occasional extreme tides caused by unusually ...

Richard D. Ray

2007-07-01T23:59:59.000Z

392

Thermodynamics in variable speed of light theories  

SciTech Connect

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

393

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

2007-11-06T23:59:59.000Z

394

CDIAC Climate Data: Available Variables  

NLE Websites -- All DOE Office Websites (Extended Search)

Climate Variables Available in CDIAC Data Products Temperature Precipitation Cloudiness Sunshine Duration Snowfall and Snow Depth Atmospheric Pressure Atmospheric Moisture Surface...

395

Approximate k-NN delta test minimization method using genetic algorithms: Application to time series  

Science Conference Proceedings (OSTI)

In many real world problems, the existence of irrelevant input variables (features) hinders the predictive quality of the models used to estimate the output variables. In particular, time series prediction often involves building large regressors of ... Keywords: Approximate k-nearest neighbors, Delta test, Genetic algorithm, Time series, Variable projection, Variable scaling, Variable selection

Fernando Mateo; Duan Sovilj; Rafael Gadea

2010-06-01T23:59:59.000Z

396

Statistical Timing Analysis using Levelized Covariance Propagation  

Science Conference Proceedings (OSTI)

Variability in process parameters is making accurate timing analysis of nano-scale integrated circuits an extremely challenging task. In this paper, we propose a new algorithm for statistical timing analysis using Levelized Covariance Propagation (LCP). ...

Kunhyuk Kang; Bipul C. Paul; Kaushik Roy

2005-03-01T23:59:59.000Z

397

Statistical characterization of library timing performance  

Science Conference Proceedings (OSTI)

With the scaling of technology, the variability of timing performances of digital circuits is increasing. In this paper, we propose a first order analytical modeling of the standard deviations of basic CMOS cell timings. The proposed model is then used ...

V. Migairou; R. Wilson; S. Engels; N. Azemard; P. Maurine

2006-09-01T23:59:59.000Z

398

Managing time  

Science Conference Proceedings (OSTI)

Professionals overwhelmed with information glut can find hope from new insights about time management.

Peter J. Denning

2011-03-01T23:59:59.000Z

399

Going with the wind: The time for time-of-use tariffs.  

E-Print Network (OSTI)

??This work project consists on the proposal of a product/service Variable Time of Use Tariff to enhance the innovativeness of the portfolio of (more)

Soares, Henrique de Brito Aranha Machado

2012-01-01T23:59:59.000Z

400

Entropic Time  

Science Conference Proceedings (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

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

On Sub-ENSO Variability  

Science Conference Proceedings (OSTI)

Multichannel singular spectrum analysis (MSSA) of surface zonal wind, sea surface temperature (SST), 20 isotherm depth, and surface zonal current observations (between 1990 and 2004) identifies three coupled oceanatmosphere modes of variability ...

Noel S. Keenlyside; Mojib Latif; Anke Drkop

2007-07-01T23:59:59.000Z

402

Imaging of lateral spin valves with soft x-ray microscopy  

SciTech Connect

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

403

Reviews of ASME Section 11 pump and valve relief requests: Post Generic Letter 89-04  

SciTech Connect

This paper presents a discussion of ASME Section 11 Pump and Valve Inservice Testing relief request reviews by the NRC and their contractors. Topics that will be discussed include the scope of USNRC reviews in Technical Evaluation Reports (TERs) (and Safety Evaluation, SEs); including the basis for granting relief requests, the status of relief requests in IST Program updates, and the Generic Letter 89-04 approval process; and the level of technical detail required in submitted programs. This presentation is based on the experiences of Brookhaven National Laboratory in reviewing IST Programs for the Mechanical Engineering Branch of the US Nuclear Regulatory Commission.

DiBiasio, A.

1992-07-01T23:59:59.000Z

404

Reviews of ASME Section 11 pump and valve relief requests: Post Generic Letter 89-04  

SciTech Connect

This paper presents a discussion of ASME Section 11 Pump and Valve Inservice Testing relief request reviews by the NRC and their contractors. Topics that will be discussed include the scope of USNRC reviews in Technical Evaluation Reports (TERs) (and Safety Evaluation, SEs); including the basis for granting relief requests, the status of relief requests in IST Program updates, and the Generic Letter 89-04 approval process; and the level of technical detail required in submitted programs. This presentation is based on the experiences of Brookhaven National Laboratory in reviewing IST Programs for the Mechanical Engineering Branch of the US Nuclear Regulatory Commission.

DiBiasio, A.

1992-01-01T23:59:59.000Z

405

Combined cycle electric power plant with a steam turbine having a sliding pressure main bypass and control valve system  

SciTech Connect

A combined cycle electric power plant includes two gas turbines, a steam turbine, and a digital control system with an operator analog or manual backup. Each of the gas turbines has an exhaust heat recovery steam generator connected to a common header from which the steam is supplied by one or both of the steam generators for operating the steam turbine. The control system is of the sliding pressure type and maintains a predetermined steam pressure as a function of steam flow according to a predetermined characterization depending on the number of steam generators in service to limit the maximum steam velocity through the steam generators, and reduce the probability of water carryover into the steam turbine. Such control is always maintained by the bypass valve. The turbine control valve responds to the speed/load demand only, except when the bypass valve is closed and the rate of steam generation is insufficient to maintain a predetermined pressure flow relationship.

Uram, R.

1980-05-06T23:59:59.000Z

406

A visual inspection system for evaluating the interior surface of valve stems on material storage container tops  

SciTech Connect

A nondestructive inspection for evaluating the interior surface of the small diameter valve stems on material storage container tops was mandated. The specifications required that the interior surface of the valve stem have a surface finish of {number sign}16 or better. Conventional methods which utilizes mechanical stylus-type''surface analyzing equipment could not extend into the narrow 0.312 inch diameter by 1.5 inch deep hole (of the valve stem). A visual inspection system which exploits the capabilities of a high resolution fiberoptic borescope was designed and assembled to resolve this requirement. This paper discusses the design and inspection features of the aforementioned system and includes several illustrations of inspection results. 6 figs.

Pickett, C.A.

1990-12-01T23:59:59.000Z

407

Energy Storage on the Grid and the Short-term Variability of Wind.  

E-Print Network (OSTI)

??Wind generation presents variability on every time scale, which must be accommodated by the electric grid. Limited quantities of wind power can be successfully integrated (more)

Hittinger, Eric Stephen

2012-01-01T23:59:59.000Z

408

Heart Rate Variability in Mice with Coronary Heart Disease  

E-Print Network (OSTI)

Heart rate variability (HRV), the beat-to-beat fluctuation of the heart rate, is a noninvasive test that measures the autonomic regulation of the heart. Assessment of HRV has been shown to predict the risk of mortality in patients after an acute myocardial infarction. Recently, the Krieger lab at MIT developed genetically engineered double knockout (dKO) mice that develop coronary artery disease accompanied by spontaneous myocardial infarctions and die at a very young age. This thesis investigated whether HRV could function as a prognostic indicator in the dKO mouse. A novel method for estimating physiological state of the mouse from the electrocardiogram using an innovative activity index was developed in order to compare HRV variables at different times while controlling for physiologic state. Traditional time and frequency domain variables were used to assess the prognostic power of HRV. Results have shown that none of the HRV variables were helpful in predicting

Laurence Zapanta; Roger G. Mark

2005-01-01T23:59:59.000Z

409

IS ACTIVE REGION CORE VARIABILITY AGE DEPENDENT?  

Science Conference Proceedings (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

410

ENSEMBLE VARIABILITY OF NEAR-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI  

Science Conference Proceedings (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

411

Motor-operated valve reliability programs: Lessons learned to meet new NRC (Nuclear Regulatory Commission) requirements  

Science Conference Proceedings (OSTI)

In recent years, reliability problems have surfaced with power plant motor-operated valves (MOVs) that (a) fail to perform as designed, and/or (b) require excessive maintenance to perform their intended function. As a result, the US Nuclear Regulatory Commission (NRC) mandated certain testing and reporting requirements in inspection and enforcement bulletin 85-03 (85-03). The NRC's generic letter 89-10 (89-10) significantly expands these requirements, to include all safety-related and position-changeable MOVs. The MOV program experience at the Sacramento Municipal Utility District (SMUD) Rancho Seco plant is particularly valuable since the NRC, to a large extent, utilized this program as the prototype for 89-10's requirements. The MOV inspection, overhaul, and testing began in September 1986, with completion scheduled for December 1986. The paper discusses problems encountered, recovery plant, results of recovery planning, and lessons learned. Experience at Rancho Seco has shown that comprehensive valve programs incorporating appropriate design practices, preventive maintenance practices, and operational constraints can improve plant availability.

Anderson, M.W.; Fadel, D.P.; Fraser, P.J.

1990-06-01T23:59:59.000Z

412

Engine cooling system air venting arrangement with buoyant air purge valve  

Science Conference Proceedings (OSTI)

An air vent arrangement is described for the cooling system of an automotive type engine having a radiator with a coolant inlet. The engine has coolant passages communicating with the radiator through an outlet essentially horizontally disposed, tubing connecting the radiator inlet and coolant outlet, and a thermostat in the outlet horizontally movable to open and closed positions. A horizontally disposed air bleed bypass passage is located vertically above the thermostat connecting the coolant outlet to a portion of the tubing downstream of the thermostat bypassing the same when the thermostat is in a closed position for bleeding air from the cooling system. The bypass passage has a valve therein moveable between a position blocking flow of coolant through the same and a second position opening the passage permitting the bleed of air therethrough. The valve is buoyant and constructed and arranged to pivot from a non flowblocking air bleed position into a flow blocking position in response to flow of coolant into the bypass passage acting thereagainst.

Schnizlein, M.E.

1987-02-17T23:59:59.000Z

413

Sealing of process valves for the HEU downblending verification experiment at Portsmouth  

SciTech Connect

At the Portsmouth Gaseous Diffusion Plant in Piketon, Ohio, USA, excess inventory of highly-enriched uranium (HEU) from US defense programs is being diluted to low-enriched uranium (LEU) for commercial use. The conversion is subject to a Verification Experiment overseen by the International Atomic Energy Agency (IAEA). The Verification Experiment is making use of monitoring technologies developed and installed by several DOE laboratories. One of the measures is a system for sealing valves in the process piping, which secures the path followed by uranium hexafluoride gas (UF{sub 6}) from cylinders at the feed stations to the blend point, where the HEU is diluted with LEU. The Authenticated Item Monitoring System (AIMS) was the alternative proposed by Sandia National Laboratories that was selected by the IAEA. Approximately 30 valves were sealed by the IAEA using AIMS fiber-optic seals (AFOS). The seals employ single-core plastic fiber rated to 125 C to withstand the high-temperature conditions of the heated piping enclosures at Portsmouth. Each AFOS broadcasts authenticated seal status and state-of-health messages via a tamper-protected radio-frequency transmitter mounted outside of the heated enclosure. The messages are received by two collection stations, operated redundantly.

Baldwin, G.T.; Bartberger, J.C.; Jenkins, C.D.; Perlinski, A.W.; Schoeneman, J.L. [Sandia National Labs., Albuquerque, NM (United States); Gordon, D.M. [Brookhaven National Lab., Upton, NY (United States); Whiting, N.E. [International Atomic Energy Agency (IAEA); Bonner, T.N.; Castle, J.M. [Lockheed Martin Utility Services, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant

1998-07-01T23:59:59.000Z

414

Interannual Variability of the Global Radiation Budget  

Science Conference Proceedings (OSTI)

Interannual variability of the global radiation budget, regions that contribute to its variability, and what limits albedo variability are investigated using Clouds and the Earths Radiant Energy System (CERES) data taken from March 2000 through ...

Seiji Kato

2009-09-01T23:59:59.000Z

415

Variable focal length deformable mirror  

DOE Patents (OSTI)

A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)

2007-06-12T23:59:59.000Z

416

4-80 Two rigid tanks connected by a valve to each other contain air at specified conditions. The volume of the second tank and the final equilibrium pressure when the valve is opened are to be determined.  

E-Print Network (OSTI)

. Treating air as an ideal gas, the volume of the second tank and the mass of air in the first tank temperatures and pressures in ideal gas calculations. Using gage pressures would result in pressure drop of 04-40 4-80 Two rigid tanks connected by a valve to each other contain air at specified conditions

Bahrami, Majid

417

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 plant expenses, it is imperative to develop and deploy a tool that can help plants benchmark operating performance. This paper introduces a benchmarking methodology designed to meet this need. The "Energy Conversion Index" (ECI) ratios the "value" of utilities exported from the power plant to the actual cost of the fuel and electricity required to produce them, generating a single number or "index." Variable cost performance is benchmarked by comparing the index from one period of time to the index of another comparable period of time. Savings (or costs) attributable to excellent (or poor) performance can easily be calculated by using the former period's index to project the current period's cost.

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

1998-04-01T23:59:59.000Z

418

Multiport solid-state imager characterization at variable pixel rates  

SciTech Connect

The imaging performance of an 8-port Full Frame Transfer Charge Coupled Device (FFT CCD) as a function of several parameters including pixel clock rate is presented. The device, model CCD- 13, manufactured by English Electric Valve (EEV) is a 512 {times} 512 pixel array designed with four individual programmable bidirectional serial registers and eight output amplifiers permitting simultaneous readout of eight segments (128 horizontal {times} 256 vertical pixels) of the array. The imager was evaluated in Los Alamos National Laboratory`s High-Speed Solid-State Imager Test Station at true pixel rates as high as 50 MHz for effective imager pixel rates approaching 400 MHz from multiporting. Key response characteristics measured include absolute responsivity, Charge-Transfer-Efficiency (CTE), dynamic range, resolution, signal-to-noise ratio, and electronic and optical crosstalk among the eight video channels. Preliminary test results and data obtained from the CCD-13 will be presented and the versatility/capabilities of the test station will be reviewed.

Yates, G.J.; Albright, K.A. [Los Alamos National Lab., NM (United States); Turko, B.T. [Lawrence Berkeley Lab., CA (United States)

1993-08-01T23:59:59.000Z

419

The TAOS Project Stellar Variability II. Detection of 15 Variable Stars  

SciTech Connect

The Taiwanese-American Occultation Survey (TAOS) project has collected more than a billion photometric measurements since 2005 January. These sky survey data - covering timescales from a fraction of a second to a few hundred days - are a useful source to study stellar variability. A total of 167 star fields, mostly along the ecliptic plane, have been selected for photometric monitoring with the TAOS telescopes. This paper presents our initial analysis of a search for periodic variable stars from the time-series TAOS data on one particular TAOS field, No. 151 (RA = 17{sup h} 30{sup m} 6.67{sup s}, Dec = 27 degrees, 17 minutes, 30 seconds, J2000), which had been observed over 47 epochs in 2005. A total of 81 candidate variables are identified in the 3 square degree field, with magnitudes in the range 8 < R < 16. On the basis of the periodicity and shape of the lightcurves, 32 variables, 18 of which were previously unknown, are classified as RR Lyrae, Cepheid, {delta} Scuti, SX Phonencis, semi-regular and eclipsing binaries.

Mondal, S; Lin, C C; Zhang, Z W; Alcock, C; Axelrod, T; Bianco, F B; Byun, Y I; Coehlo, N K; Cook, K H; Dave, R; Kim, D W; King, S K; Lee, T; Lehner, M J; Lin, H C; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, J H; Wang, S Y; Wen, C Y

2010-01-28T23:59:59.000Z

420

Variable Interactions in Query-Driven Visualization  

SciTech Connect

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

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
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421

Modeling and optimizing passive valve designs for the implantable Gold Micro-Shunt used in glaucoma treatment  

Science Conference Proceedings (OSTI)

Glaucoma is an age-related eye disease that causes ocular nerve damage, typically characterized by elevated intraocular pressure (IOP). Studies have shown that IOP can vary significantly on the order of days or even hours. Failure to control IOP spikes ... Keywords: Check-valve, Drainage device, Finite element analysis, Glaucoma, Intraocular pressure, MEMS

Judy L. Lin; Jason M. Clevenger

2009-06-01T23:59:59.000Z

422

Operating Reserves and Variable Generation  

DOE Green Energy (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

423

NREL Variability and Reserves Analysis for the Western Interconnect (Presentation)  

DOE Green Energy (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

424

Exploring the Interplay between Natural Decadal Variability and Anthropogenic Climate Change in Summer Rainfall over China. Part I: Observational Evidence  

Science Conference Proceedings (OSTI)

Summer rainfall over China has experienced substantial variability on longer time scales during the last century, and the question remains whether this is due to natural, internal variability or is part of the emerging signal of anthropogenic ...

Yonghui Lei; Brian Hoskins; Julia Slingo

2011-09-01T23:59:59.000Z

425

Digestion time  

NLE Websites -- All DOE Office Websites (Extended Search)

Digestion time Digestion time Name: Don Mancosh Location: N/A Country: N/A Date: N/A Question: I have always given the rule of thumb in class that material we eat is with us for about 24 hours before exiting the body. The question arises about the time value of liquids. Getting a big coke prior to a 3 hour drive generally means that there will be a stop along the way. Is there a generalization made about liquids in the body similar to the one for solid food? Replies: A physician would give a better answer, but I hazard this: the only liquids which people consume (deliberately) in significant quantities are water, ethyl alcohol and various oils. Water and alcohol are absorbed on a time scale of seconds to minutes through the mouth, stomach and digestive tract. The oils are huge molecules, so I'd guess like any other greasy food they get absorbed in the upper digestive tract. Some of them, perhaps the longest and most nonpolar, are not absorbed at all --- cf. the old-time remedy of mineral oil for constipation --- so there should be some average time-before-what's-left-is-excreted such as you're looking for, and my (wild) guess is that it would not differ substantially from that for food. You can define an average lifetime in the body for alcohol, since the natural level is zero. Rough guidelines are widespread in the context of drunk driving laws. But this is not really possible for water. One's body is normally full up to the brim with water, and there's no way for the body to distinguish between water molecules recently absorbed and molecules that've been moping around since the Beatles split up. Thus the water entering the toilet bowl after the pit stop is not in general the same water as was in the big coke. If you were to consider for water just the average time between drinking and peeing, it would seem to depend strongly on how well hydrated the body was before the drink, and how much was drunk. During sustained heavy exertion in the sun and dry air one can easily drink a pint of water an hour without peeing at all. On the other hand, if one is willing to drink enough water fast enough, so as to establish a high excess of body water one can pee 8 ounces 15 minutes or less after drinking 8 ounces.

426

DOE-SPEC-3019-96; Valve-Regulated Type Lead-Acid Storage Batteries  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

9-96 9-96 August 1996 DOE SPECIFICATION VALVE-REGULATED TYPE LEAD-ACID STORAGE BATTERIES U.S. Department of Energy FSC 6140 Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; (423) 576-8401. Available to the public from the U.S. Department of Commerce, Technology Administration, National Technical Information Service, Springfield, VA 22161; (703) 487-4650. Order No. DE96009470 DOE-SPEC-3019-96 THIS PAGE INTENTIONALLY LEFT BLANK DOE-SPEC-3019-96 iii FOREWORD 1. Use of this purchase specification is not mandatory. User should review the document and

427

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

SciTech Connect

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.

Savannah River Site (SRS), Aiken, SC (United States); Villanova University, Villanova, PA (United States); exida, Sellersville, PA (United States)

2013-04-16T23:59:59.000Z

428

Performance Evaluation of Hot Water Efficiency Plumbing System Using Thermal Valve  

E-Print Network (OSTI)

In Korea two popular water distribution systemsthe branch type and the separate type systemshave serious drawbacks. The branch type suffers from temperature instability while the separate type suffers from excessive piping. Neither of them re-circulates water. The system proposed in this paper utilizes a water-conserving piping system with a thermostat valve. This paper compares the proposed system with that of the separate type. Our findings show that the proposed system wastes less water. After re-circulating for 78-87 seconds, water is available at set point temperature (40C). Also, when multiple water taps are in use, the average temperature deviation is less than 0.6C. Moreover, the proposed system has 50% less flow rate than the separate type system.

Cha, K. S.; Park, M. S.; Seo, H. Y.

2010-08-01T23:59:59.000Z

429

Irradiation-controlled giant magnetoresistance of PtMn-based spin valve  

Science Conference Proceedings (OSTI)

He{sup +}-ion irradiation resulted in the direct ordering of PtMn without postannealing. Samples were irradiated with 2 MeV He{sup +} ions and a beam current of 1.08 {mu}A/cm{sup 2} such that the corresponding surface temperature was 190 deg. C. The exchange bias direction was set in situ during irradiation in a field of 900 Oe. A high giant magnetoresistance (GMR) ratio of 11% was obtained in PtMn-based spin valves after He{sup +} irradiation. The GMR is completely eliminated after it is irradiated with oxygen ions at 42 keV. Combining He{sup +} with oxygen-ion irradiation can provide magnetic patterning for GMR sensors.

Huang, S.-H.; Lai, C.-H.; Chiang, C. C.; Yang, C.-H. [Department of Materials Science and Engineering, National Tsing Huang University, 101, Section 2, Kuang Fu Road, Hsinchu, Taiwan 30013 (China)

2006-04-15T23:59:59.000Z

430

Preliminary design for hot dirty-gas control-valve test facility. Final report  

SciTech Connect

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

431

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. 1.

C. D. Impey; C. E. Petry; Csar Briceo

2003-01-01T23:59:59.000Z

432

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.

Briceo, C

2003-01-01T23:59:59.000Z

433

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

434

Lecture 2227 Continuous Random Variables  

E-Print Network (OSTI)

-x/100 dx = -e-x/100 100 0 = 1 - e-1 = .632 text typo Example 3 (Light Bulb): The lifetime X, in hours, of a certain kind of light bulb is a continuous random variable with density f(x) = 1500 x2 I(1500,) Check = 1 4 = p Let B denote the number of failures before 2000 hours among 5 light bulbs. Then P(B 1) = P

Scholz, Fritz

435

Lecture 2227 Continuous Random Variables  

E-Print Network (OSTI)

) = 100 0 1 100 e-x/100 dx = -e-x/100 100 0 = 1 - e-1 = .632 text typo Example 3 (Light Bulb): The lifetime X, in hours, of a certain kind of light bulb is a continuous random variable with density f 2000 1500 = 1 - 3 4 = 1 4 = p Let B denote the number of failures before 2000 hours among 5 light bulbs

Scholz, Fritz

436

Determination of variable dependence information through abstract interpretation  

E-Print Network (OSTI)

Traditional schemes for abstract interpretation-based global analysis of logic programs generally focus on obtaining procedure argument mode and type information. Variable sharing information is often given only the attention needed to preserve the correctness of the analysis. However, such sharing information can be very useful. In particular, it can be used for predicting run-time goal independence, which can eliminate costly run-time checks in interpretation in logic programs is described which infers the dependencies of the terms bound to program variables with increased precision and at all points in the execution of the program, rather than just at a procedure level. Algorithms are presented for computing abstract entry and success substitutions which extensively keep track of variable aliasing and term dependence information. The algorithms are illustrated with examples. 1

K. Muthukumar; M. Hermenegildo

1989-01-01T23:59:59.000Z

437

Climatic variability within an equilibrium greenhouse simulation  

SciTech Connect

A simulation of the possible consequences of a doubling of the CO{sub 2} content of the atmosphere has been performed with a low resolution global climatic model. The model included the diurnal and seasonal computed sea ice amount and cloud cover, and used implied oceanic heat fluxes to represent transport processes in the oceans. A highly responsive 2-layer soil moisture formulation was also incorporated. Twenty year equilibrated simulations for control (1xCO{sub 2}) and greenhouse (2xCO{sub 2}) conditions were generated. The major emphasis of the analysis presented here is on the intra-annual and interannual variability of the greenhouse run with respect to the control run. This revealed considerable differences from the time-averaged results with occasions of marked positive and negative temperature deviations. Of particular interest were the periods of negative temperature departures compared to the control run which were identified, especially over the Northern Hemisphere continents. Temporal and spatial precipitation and soil moisture anomalies also occurred, some of which were related to the surface temperature changes. Substantial sea surface temperature anomalies were apparent in the greenhouse run, indicating that a source of climatic forcing existed in addition to that due to doubling of the CO{sub 2}. Comparison of the intra-annual and interannual variability of the control run with that of the greenhouse run suggests that, in many situations, it will be difficult to identify a greenhouse signal against the intrinsic natural variability of the climatic system. 35 refs., 20 figs., 1 tab.

Gordon, H.B.; Hunt, B.G. [CSIRO Division of Atmospheric Research, Victoria (Austria)

1994-01-01T23:59:59.000Z

438

Changes in the Economic Value of Variable Generation at High Penetration Levels: A Pilot Case Study of California  

E-Print Network (OSTI)

difference between the real-time price and the actual real-2008) used historic real-time prices and simulated long-runin the real-time (RT) market at the RT price. Variable

Mills, Andrew

2013-01-01T23:59:59.000Z

439

Limited Temporal Variability of Arsenic Concentrations in 20 Wells  

E-Print Network (OSTI)

Limited Temporal Variability of Arsenic Concentrations in 20 Wells Monitored for 3 Years switched their water consumption to wells that meet the local standard for As in drinking water of 50 µg if As concentrations in those wells could change over time. To address this issue, we report here precise groundwater

van Geen, Alexander

440

A Simulation of Variability of ENSO Forecast Skill  

Science Conference Proceedings (OSTI)

In many prediction schemes, the skill of long-range forecasts of ENSO events depends on the time of year. Such variability could be directly due to seasonal changes in the basic ocean-atmosphere system or due to the state of ENSO itself.

M. K. Davey; D. L. T. Anderson; S. Lawrence

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.


441

Modeling the Variability of the Greater Agulhas Current System  

Science Conference Proceedings (OSTI)

An eddy-permitting, regional ocean model has been used to examine the variability in the source regions of the Agulhas Current on a range of time scales. These source regions are the East Madagascar Current, the flow through the Mozambique ...

J. C. Hermes; C. J. C. Reason; J. R. E. Lutjeharms

2007-07-01T23:59:59.000Z

442

Decadal Variability in a Simplified Wind-Driven Ocean Model  

Science Conference Proceedings (OSTI)

The impact of an unsteady wind forcing on oceanic low-frequency variability is conceptually studied using a reduced-gravity shallow-water model. A time-averaged wind forcing and a simple oceanatmosphere coupling is completed by a stochastic ...

Philip Sura; Frank Lunkeit; Klaus Fraedrich

2000-08-01T23:59:59.000Z

443

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

E-Print Network (OSTI)

Solar activity and earth rotation variability R. Abarca del Rioa, *, D. Gambisb , D. Salsteinc , P to investigate a possible connection with solar activity fluctuations from interannual to secular time scales in AAM and LOD agrees with that in solar activity with regard to the decadal cycle in the stratospheric

Dai, Aiguo

444

Variability of Load and Net Load in Case of Large Scale Distributed Wind Power  

Science Conference Proceedings (OSTI)

Large scale wind power production and its variability is one of the major inputs to wind integration studies. This paper analyses measured data from large scale wind power production. Comparisons of variability are made across several variables: time scale (10-60 minute ramp rates), number of wind farms, and simulated vs. modeled data. Ramp rates for Wind power production, Load (total system load) and Net load (load minus wind power production) demonstrate how wind power increases the net load variability. Wind power will also change the timing of daily ramps.

Holttinen, H.; Kiviluoma, J.; Estanqueiro, A.; Gomez-Lazaro, E.; Rawn, B.; Dobschinski, J.; Meibom, P.; Lannoye, E.; Aigner, T.; Wan, Y. H.; Milligan, M.

2011-01-01T23:59:59.000Z

445

Time-independent and time-dependent contributions to the unavailability of standby safety system components  

Science Conference Proceedings (OSTI)

The unavailability of standby safety system components due to failures in nuclear power plants is considered to involve a time independent and a time dependent part. The former relates to the component`s unavailability from demand stresses due to usage, and the latter represents the component`s unavailability due to standby time stresses related to the environment. In this paper, data from the nuclear plant reliability data system (NPRDS) were used to partition the component`s unavailability into the contributions from standby time stress (i.e., due to environmental factors) and demand stress (i.e., due to usage). Analyses are presented of motor operated valves (MOVs), motor driven pumps (MDPs), and turbine driven pumps (FDPs). MOVs fail predominantly (approx. 78%) from environmental factors (standby time stress failures). MDPs fail slightly more frequently from demand stresses (approx. 63%) than standby time stresses, while TDPs fail predominantly from standby time stresses (approx. 78%). Such partitions of component unavailability have many uses in risk informed and performance based regulation relating to modifications to Technical Specification, in-service testing, precise determination of dominant accident sequences, and implementation of maintenance rules.

Lofgren, E.V. [Science Applications International Corp., Fairfax Station, VA (United States); Uryasev, S.; Samanta, P. [Brookhaven National Lab., Upton, NY (United States)

1997-03-01T23:59:59.000Z

446

Searching for Variability in the Globular Cluster Messier 4  

E-Print Network (OSTI)

Time-series data taken with the Hubble Space Telescope of a field six core radii (~5') from the center of the globular cluster Messier 4, and covering a period of about 10 weeks in early 2001, have been analyzed in search of variable objects. Various criteria were employed to select candidate variable stars. Period searches were performed on the selected candidates using phase dispersion minimization (PDM). The reliability of the PDM search results was tested using synthetic light curves of eclipsing binary stars and sinusoidal light curves of different periods. Results from this analysis showed that there are probably no eclipsing binary stars or periodic variables in our field with periods on the order of a few hours to a few days, down to limiting magnitudes of V~25 and I~24, which is consistent with the absence of contact binaries such as W Ursae Majoris systems. However, one candidate variable star does show an increase in brightness of ~0.1 magnitudes in both bandpasses, which seems to last for a few days. Possible explanations concerning the nature of this object include a binary system with a white dwarf primary and a low-mass main sequence secondary, or a BY Draconis variable star. We are able to set an upper limit to the observed fraction of photometric variability in this dataset of 0.05%.

Robert D. Ferdman; Harvey B. Richer; James Brewer; Greg G. Fahlman; Brad K. Gibson; Brad M. S. Hansen; Mark E. Huber; Rodrigo A. Ibata; Jasonjot S. Kalirai; Jaymie M. Matthews; R. Michael Rich; Jason F. Rowe; Michael M. Shara; Peter B. Stetson

2003-04-25T23:59:59.000Z

447

Time Brightness  

NLE Websites -- All DOE Office Websites (Extended Search)

Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Perlmutter, et al., in Thermonuclear Supernovae, NATO ASI, v. 486 (1997) Cosmology from . . . Time Brightness ... . . . 50-100 Fields Lunar Calendar Scheduled Follow-Up Imaging at Hubble, Cerro Tololo, WIYN, Isaac Newton Scheduled Follow-Up Spectroscopy at Keck Almost 1000 Galaxies per Field RESULT: ~24 Type Ia supernovae discovered while still brightening, at new moon Berkeley Lab Keck WIYN Cerro Tololo Isaac Newton Hubble Strategy We developed a strategy to guarantee a group of supernova discoveries on a certain date. Just after a new moon, we observe some 50 to 100 high-galactic lattitute fields-each containing almost a thousand high-redshift galaxies-in two nights on the Cerro Tololo 4-meter telescope with Tyson & Bernstein's wide-field camera. We return three weeks later to observe the same

448

The analysis and specification of large high-pressure, high-temperature valves for combustion turbine protection in second-generation PFB power plants: Topical report  

SciTech Connect

The purpose of this study was to provide a specification for the high-pressure/high-temperature valves for turbine overspeed protection in a commercial-scale second-generation pressurized fluidized bed combustion (PFBC) power plant. In the event of a loss of external (generator) load, the gas turbine rapidly accelerates from its normal operating speed. Protection from excessive overspeed can be maintained by actuation of fuel isolation and air bypass valves. A design specification for these valves was developed by analyses of the turbine/compressor interaction during a loss of load and analyses of pressure and flow transients during operation of the overspeed protection valves. The basis for these analyses was the Phase 1 plant conceptual design prepared in 1987.

1994-08-01T23:59:59.000Z

449

Proceedings of the Third NRC/ASME Symposium on Valve and Pump Testing. Session 1A--Session 2C: Volume 1  

Science Conference Proceedings (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

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

Quantum computation and hidden variables  

E-Print Network (OSTI)

Many physicists limit oneself to an instrumentalist description of quantum phenomena and ignore the problems of foundation and interpretation of quantum mechanics. This instrumentalist approach results to "specialization barbarism" and mass delusion concerning the problem, how a quantum computer can be made. The idea of quantum computation can be described within the limits of quantum formalism. But in order to understand how this idea can be put into practice one should realize the question: "What could the quantum formalism describe?", in spite of the absence of an universally recognized answer. Only a realization of this question and the undecided problem of quantum foundations allows to see in which quantum systems the superposition and EPR correlation could be expected. Because of the "specialization barbarism" many authors are sure that Bell proved full impossibility of any hidden-variables interpretation. Therefore it is important to emphasize that in reality Bell has restricted to validity limits of the no- hidden-variables proof and has shown that two-state quantum system can be described by hidden variables. The later means that no experimental result obtained on two-state quantum system can prove the existence of superposition and violation of the realism. One should not assume before unambiguous experimental evidence that any two-state quantum system is quantum bit. No experimental evidence of superposition of macroscopically distinct quantum states and of a quantum bit on base of superconductor structure was obtained for the present. Moreover same experimental results can not be described in the limits of the quantum formalism.

V. V. Aristov; A. V. Nikulov

2010-07-12T23:59:59.000Z

452

Nonferromagnetic linear variable differential transformer  

DOE Patents (OSTI)

A nonferromagnetic linear variable differential transformer for accurately measuring mechanical displacements in the presence of high magnetic fields is provided. The device utilizes a movable primary coil inside a fixed secondary coil that consists of two series-opposed windings. Operation is such that the secondary output voltage is maintained in phase (depending on polarity) with the primary voltage. The transducer is well-suited to long cable runs and is useful for measuring small displacements in the presence of high or alternating magnetic fields.

Ellis, James F. (Powell, TN); Walstrom, Peter L. (Oak Ridge, TN)

1977-06-14T23:59:59.000Z

453

Structure Function Analysis of Long Term Quasar Variability  

E-Print Network (OSTI)

In our second paper on long-term quasar variability, we employ a much larger database of quasars than in de Vries, Becker & White. This expanded sample, containing 35165 quasars from the Sloan Digital Sky Survey Data Release 2, and 6413 additional quasars in the same area of the sky taken from the 2dF QSO Redshift Survey, allows us to significantly improve on our earlier conclusions. As before, all the historic quasar photometry has been calibrated onto the SDSS scale by using large numbers of calibration stars around each quasar position. We find the following: (1) the outbursts have an asymmetric light-curve profile, with a fast-rise, slow-decline shape; this argues against a scenario in which micro-lensing events along the line-of-sight to the quasars are dominating the long-term variations in quasars; (2) there is no turnover in the Structure Function of the quasars up to time-scales of ~40 years, and the increase in variability with increasing time-lags is monotonic and constant; and consequently, (3) there is not a single preferred characteristic outburst time-scale for the quasars, but most likely a continuum of outburst time-scales, (4) the magnitude of the quasar variability is a function of wavelength: variability increases toward the blue part of the spectrum, (5) high-luminosity quasars vary less than low-luminosity quasars, consistent with a scenario in which variations have limited absolute magnitude. Based on this, we conclude that quasar variability is intrinsic to the Active Galactic Nucleus, is caused by chromatic outbursts / flares with a limited luminosity range and varying time-scales, and which have an overall asymmetric light-curve shape. Currently the model that has the most promise of fitting the observations is based on accretion disk instabilities.

W. H. de Vries; R. H. Becker; R. L. White; C. Loomis

2004-11-12T23:59:59.000Z

454

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

455

Compilation and Evaluation of NOREM (TM) Test Results: Implications for Valve Applications: Generic Background Information for 10 CF R 50.59 Evaluations  

Science Conference Proceedings (OSTI)

EPRI's iron-base NOREM(TM) hardfacing alloy represents a viable generic substitute for cobalt-base Stellite(TM) hardfacing alloys in nuclear valve applications. Based on a wide array of evaluations, this report identifies an acceptable range of conditions for using NOREM in nuclear plant valves to replace cobalt-base hardfacing alloys. The report should prove valuable to utility personnel responsible for performing 10 CFR 50.59 evaluations of NOREM replacements.

1999-06-30T23:59:59.000Z

456

Modeling the Effect of Land Surface Evaporation Variability on Precipitation Variability. Part I: General Response  

Science Conference Proceedings (OSTI)

This is the first of a two-part article that investigates the impact of land surface evaporation variability on the interannual variability of precipitation and compares it with the impact caused by sea surface temperature variability. Previous ...

Oreste Reale; Paul Dirmeyer

2002-08-01T23:59:59.000Z

457

Variable Iron K-alpha Lines in Seyfert 1 Galaxies  

E-Print Network (OSTI)

We find that variability of the iron K-alpha line is common in Seyfert 1 galaxies. Using data from the ASCA archive for objects that have been observed more than once during the mission, we study the time-averaged spectra from individual observations, thereby probing variability on timescales that range from days to years. Since the statistics of the data do not warrant searches for line variability in terms of a complex physical model, we use a a simple Gaussian to model the gross shape of the line, and then use the centroid energy, intensity and equivalent width as robust indicators of changes in the line profile. We find that ~70% of Seyfert 1s (ten out of fifteen) show variability in at least one of these parameters: the centroid energy, intensity, and equivalent width vary in six, four, and eight sources respectively. Due to the low S/N, limited sampling and time averaging, we consider these results to represent lower limits to the rate of incidence of variability. In most cases changes in the line do not appear to track changes in the continuum. In particular, we find no evidence for variability of the line intensity in NGC 4151, suggesting an origin in a region larger than the putative accretion disk, where most of the iron line has been thought to originate. Mkn 279 is investigated on short timescales. The time-averaged effective line energy is 6.5 keV in the galaxy rest frame. As the continuum flux increases by 20% in a few hours, the Fe K line responds with the effective line energy increasing by 0.22 keV (~10,500 km s^-1). Problems with the ASCA and Rosat calibration that affect simultaneous spectral fits are discussed in an appendix.

K. A. Weaver; J. Gelbord; T. Yaqoob

2000-08-31T23:59:59.000Z

458

A Main Steam Safety Valve (MSSV) With Fixed Blowdown According to ASME Section III,Part NC-7512  

Science Conference Proceedings (OSTI)

In 1986, the NRC issued the Information Notice (IN) 86-05 'Main Steam Safety Valve test failures and ring setting adjustments'. Shortly after this IN was issued, the Code was revised to require that a full flow test has to be performed on each CL.2 MSSV by the manufacturer to verify that the valve was adjusted so that it would reach full lift and thus full relieving capacity and would re-close at a pressure as specified in the valve Design Specification. In response to the concern discussed in the IN, the Westinghouse Owners Group (WOG) performed extensive full flow testing on PWR MSSVs and found that each valve required a unique setting of a combination of two rings in order to achieve full lift at accumulation of 3% and re-closing at a blowdown of 5%. The Bopp and Reuther MSSV type SiZ 2507 has a 'fixed blowdown' i.e. without any adjusting rings to adjust the 'blowdown' so that the blowdown is 'fixed'. More than 1000 pieces of this type are successfully in nuclear power plants in operation. Many of them since about 25 years. Therefore it can be considered as a proven design. It is new that an optimization of this MSSV type SiZ 2507 fulfill the requirements of part NC-7512 of the ASME Section III although there are still no adjusting rings in the flow part. In 2000, for the Qinshan Candu unit 1 and 2 full flow tests were performed with 32 MSSV type SiZ 2507 size 8'' x 12'' at 51 bar saturated steam in only 6 days. In all tests the functional performance was very stable. It was demonstrated by recording the signals lift and system pressure that all valves had acceptable results to achieve full lift at accumulation of 3% and to re-close at blowdown of 5%. This is an advantage which gives a reduction in cost for flow tests and which gives more reliability after maintenance work during outage compared to the common MSSV design with an individual required setting of the combination of the two rings. The design of the type SiZ 2507 without any adjusting rings in the flow path is presented. The stable performance depends on the interaction of flow force and spring force. The optimization of the flow path to create a suitable flow-force-curve was managed by Computational Fluid Dynamics (CFD) and flow-force-characteristic-measurements at a model 1: 2.5. The method of the flow-force-characteristic-measurement permits systematic dimensioning of valve spring forces by means of measurement of the fluid mechanical forces occurring on the valve spindle during flow. A special procedure was established to verify a spring force versus lift curve with an accuracy of 1% for each production valve. This gives high reliability at required stable performance and this can not be influenced by wrong setting of any adjusting ring during maintenance work. (authors)

Follmer, Bernhard; Schnettler, Armin [Bopp and Reuther Sicherheitsund Regelarmaturen, GmbH, Mannheim (Germany)

2002-07-01T23:59:59.000Z

459

Variable Average Absolute Percent Differences  

U.S. Energy Information Administration (EIA) Indexed Site

Variable Variable Average Absolute Percent Differences Percent of Projections Over- Estimated Gross Domestic Product Real Gross Domestic Product (Average Cumulative Growth)* (Table 2) 1.0 42.6 Petroleum Imported Refiner Acquisition Cost of Crude Oil (Constant $) (Table 3a) 35.2 18.6 Imported Refiner Acquisition Cost of Crude Oil (Nominal $) (Table 3b) 34.7 19.7 Total Petroleum Consumption (Table 4) 6.2 66.5 Crude Oil Production (Table 5) 6.0 59.6 Petroleum Net Imports (Table 6) 13.3 67.0 Natural Gas Natural Gas Wellhead Prices (Constant $) (Table 7a) 30.7 26.1 Natural Gas Wellhead Prices (Nominal $) (Table 7b) 30.0 27.1 Total Natural Gas Consumption (Table 8) 7.8 70.2 Natural Gas Production (Table 9) 7.1 66.0 Natural Gas Net Imports (Table 10) 29.3 69.7 Coal Coal Prices to Electric Generating Plants (Constant $)** (Table 11a)

460

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

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461

Sources of Variability of Evapotranspiration in California  

Science Conference Proceedings (OSTI)

The variability (19902002) of potential evapotranspiration estimates (ETo) and related meteorological variables from a set of stations from the California Irrigation Management System (CIMIS) is studied. Data from the National Climatic Data ...

Hugo G. Hidalgo; Daniel R. Cayan; Michael D. Dettinger

2005-02-01T23:59:59.000Z

462

Incremental Closure of Free Variable Tableaux  

Science Conference Proceedings (OSTI)

This paper presents a technique for automated theorem proving with free variable tableaux that does not require backtracking. Most existing automated proof procedures using free variable tableaux require iterative deepening and backtracking over applied ...

Martin Giese

2001-06-01T23:59:59.000Z

463

Thermocline Variability in Different Dynamic Regions  

Science Conference Proceedings (OSTI)

The response of thermocline circulation to a variable wind forcing is investigated with quasigeostrophic models. The physical mechanism responsible for the different variability features in various dynamic regions has been highlighted. Special ...

Zhengye Liu

1996-08-01T23:59:59.000Z

464

QUEST1 VARIABILITY SURVEY. III. LIGHT CURVE CATALOG UPDATE  

Science Conference Proceedings (OSTI)

This paper reports an update to the QUEST1 (QUasar Equatorial Survey Team, Phase 1) Variability Survey (QVS) light curve catalog, which links QVS instrumental magnitude light curves to Sloan Digital Sky Survey (SDSS) objects and photometry. In the time since the original QVS catalog release, the overlap between publicly available SDSS data and QVS data has increased by 8% in sky coverage and 16,728 in number of matched objects. The astrometric matching and the treatment of SDSS masks have been refined for the updated catalog. We report on these improvements and present multiple bandpass light curves, global variability information, and matched SDSS photometry for 214,941 QUEST1 objects.

Rengstorf, A. W.; Thompson, D. L. [Purdue University Calumet, Department of Chemistry and Physics, 2200 169th St., Hammond, IN 46323 (United States); Mufson, S. L.; Honeycutt, R. K.; Adams, B.; Baltay, C.; Gebhard, M. [Indiana University, 727 E. 3rd St., Bloomington, IN 47405 (United States); Andrews, P.; Coppi, P.; Emmet, W. [Yale University, Department of Physics, P.O. Box 208121, New Haven, CT 06250-8121 (United States); Vivas, A. K.; Abad, C.; Bongiovanni, A.; Briceno, C.; Bruzual, G.; Prugna, F. Della; Hernandez, J. [Centro de Investigaciones de AstronomIa, Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of); Bailyn, C. [Yale University, Department of Astronomy, P.O. Box 208101, New Haven, CT 06250-8101 (United States); Ferrin, I.; Fuenmayor, F. [Universidad de Los Andes, Apartado Postal 26, Merida 5251 (Venezuela, Bolivarian Republic of)], E-mail: adamwr@calumet.purdue.edu (and others)

2009-03-15T23:59:59.000Z

465

Changes toward Earlier Streamflow Timing across Western North America  

Science Conference Proceedings (OSTI)

The highly variable timing of streamflow in snowmelt-dominated basins across western North America is an important consequence, and indicator, of climate fluctuations. Changes in the timing of snowmelt-derived streamflow from 1948 to 2002 were ...

Iris T. Stewart; Daniel R. Cayan; Michael D. Dettinger

2005-04-01T23:59:59.000Z

466

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.

467

Studies on selection of controlled variables  

E-Print Network (OSTI)

Studies on selection of controlled variables by Vidar Alstad A Thesis Submitted for the Degree. Thus, the selection of controlled variables integrates the optimization and the control layer. Selecting the right controlled variables can be of paramount importance. Many chem­ ical processes

Skogestad, Sigurd

468

Studies on selection of controlled variables  

E-Print Network (OSTI)

Studies on selection of controlled variables by Vidar Alstad A Thesis Submitted for the Degree. Thus, the selection of controlled variables integrates the optimization and the control layer. Selecting the right controlled variables can be of paramount importance. Many chem- ical processes

Skogestad, Sigurd

469

Adaptive sampling for Bayesian variable selection  

E-Print Network (OSTI)

Adaptive sampling for Bayesian variable selection DAVID J. NOTT Department of Statistics for variable selection and for dealing with model un- certainty have become increasingly popular in recent consider adaptive Markov chain Monte Carlo schemes for Bayesian variable selection in Gaussian linear

Blennerhassett, Peter

470

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

471

SLUDGE BATCH VARIABILITY STUDY WITH FRIT 418  

SciTech Connect

The Defense Waste Processing Facility (DWPF) initiated processing Sludge Batch 6 (SB6) in the summer of 2010. In support of processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frit 418 to process SB6. This recommendation was based on assessments of the compositional projections for SB6 available at the time from the Liquid Waste Organization (LWO) and SRNL (using a model-based approach). To support qualification of SB6, SRNL executed a variability study to assess the applicability of the current durability models for SB6. The durability models were assessed over the expected Frit 418-SB6 composition range. Seventeen glasses were selected for the variability study based on the sludge projections used in the frit recommendation. Five of the glasses are based on the centroid of the compositional region, spanning a waste loading (WL) range of 32 to 40%. The remaining twelve glasses are extreme vertices (EVs) of the sludge region of interest for SB6 combined with Frit 418 and are all at 36% WL. These glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). After initiating the SB6 variability study, the measured composition of the SB6 Tank 51 qualification glass produced at the SRNL Shielded Cells Facility indicated that thorium was present in the glass at an appreciable concentration (1.03 wt%), which made it a reportable element for SB6. This concentration of ThO{sub 2} resulted in a second phase of experimental studies. Five glasses were formulated that were based on the centroid of the new sludge compositional region combined with Frit 418, spanning a WL range of 32 to 40%. These glasses were fabricated and characterized using chemical composition analysis and the PCT. Based on the measured PCT response, all of the glasses (with and without thorium) were acceptable with respect to the Environmental Assessment (EA) reference glass regardless of thermal history. All of the normalized boron releases were less than 1 g/L. While all of the targeted glass compositions were predictable with respect to the Product Composition Control System (PCCS) models for durability, a small number of the measured glass compositions were located outside of the lower prediction limit indicating poorer durability than what was actually measured. These unpredictable glasses were in the same lithium metaborate (LM) preparation block during the chemical analyses, which resulted in measured compositions that were not representative of the target compositions. A review of the data did not indicate a clear cause for the problem. Re-digestion and re-measurement of three glasses from this preparation block yielded glass compositions closer to the target values and predicted PCT responses within the PCCS model uncertainty. Therefore, it is believed that the glasses were correctly fabricated and the targeted compositions are closer representations of the true compositions. Per the requirements of the DWPF Glass Product Control Program, the PCCS durability models have been shown to be applicable for the SB6/Frit 418 glass system. PCT results from the glasses fabricated as part of the variability study were shown to be predictable and/or acceptable with respect to the DWPF PCCS models. In addition, the inclusion of ThO{sub 2} was shown to have minimal impact on the acceptability and predictability of the variability study glasses.

Johnson, F.; Edwards, T.

2010-11-29T23:59:59.000Z

472

Integration of Variable Generation and Cost-Causation (Fact Sheet)  

DOE Green Energy (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

473

Biquadratic coupling effect on magnetoresistance response curves of spin valves with a synthetic antiferromagnet  

SciTech Connect

Both normal and inverse magnetoresistance (MR) response curves were observed for synthetic spin valves with the structure of Si(100)/Ru/Co(t{sub 1})/Ru(0.7nm)/Co(t{sub 2})/Cu(3nm)/Co(t{sub 3})/Ru. Under the assumption of a coherent rotation of the magnetization in the three Co layers, the hysteresis loops, magnetization response, and MR response curves were calculated as a function of the parameters of the system. The parameters include antiferromagnetic coupling of Co(t{sub 1}) and Co(t{sub 2}) through Ru layer, a weak ferromagnetic coupling of Co(t{sub 2}) and Co(t{sub 3}) through Cu spacer, giant magnetoresistance of the Co/Cu/Co and Co/Ru/Co systems, and AMR contribution of each Co layer. The uniaxial anisotropy of each Co layer and a distribution of the coupling strength of Co(t{sub 1})/Ru/Co(t{sub 2}) were also included. To fit the experimental data well, it was necessary to include a biquadratic coupling in the Co(t{sub 1})/Ru/Co(t{sub 2}) trilayer. {copyright} 2001 American Institute of Physics.

Zhang, K.; Kai, T.; Zhao, T.; Fujiwara, H.; Mankey, G. J.

2001-06-01T23:59:59.000Z

474

Pulsating Variable Stars in the Coma Berenices dwarf spheroidal galaxy  

E-Print Network (OSTI)

We present B, V, I time-series photometry of the Coma Berenices dwarf spheroidal galaxy, a faint Milky Way satellite, recently discovered by the Sloan Digital Sky Survey. We have obtained V, B-V and V, V-I color-magnitude diagrams that reach V~23.0-23.2 mag showing the galaxy turnoff at V~21.7 mag, and have performed the first study of the variable star population of this new Milky Way companion. Two RR Lyrae stars (a fundamental-mode -RRab- and a first overtone -RRc- pulsator) and a short period variable with period P=0.12468 days were identified in the galaxy. The RRab star has a rather long period of P_ab=0.66971 days and is about 0.2 mag brighter than the RRc variable and other non-variable stars on the galaxy horizontal branch. In the period-amplitude diagram the RRab variable falls closer to the loci of Oosterhoff type-II systems and evolved fundamental-mode RR Lyrae stars in the Galactic globular cluster M3. The average apparent magnitude of the galaxy horizontal branch, =18.64+-0.04 mag, leads to a di...

Musella, I; Clementini, G; Dall'Ora, M; Kinemuchi, K; Di Fabrizio, L; Greco, C; Marconi, M; Smith, H; Radovich, M; Beers, T

2009-01-01T23:59:59.000Z

475

The Relation between Decadal Variability of Subtropical Mode Water and the North Atlantic Oscillation  

Science Conference Proceedings (OSTI)

The Bermuda station S time series has been used to define the variability of subtropical mode water (STMW) from 1954 to 1995. This record, which shows decadal variability at a nominal period of about 1214 yr, has been used as a baseline for ...

Terrence M. Joyce; Clara Deser; Michael A. Spall

2000-07-01T23:59:59.000Z

476

Extrinsic Radio Variability of JVAS/CLASS Gravitational Lenses  

E-Print Network (OSTI)

We present flux-ratio curves of the fold and cusp (i.e. close multiple) images of six JVAS/CLASS gravitational lens systems. The data were obtained over a period of 8.5 months in 2001 with the Multi-Element Radio-Linked Interferometer Network (MERLIN) at 5-GHz with 50 mas resolution, as part of a MERLIN Key-Project. Even though the time delays between the fold and cusp images are small (<~1 day) compared to the time-scale of intrinsic source variability, all six lens systems show evidence that suggests the presence of extrinsic variability. In particular, the cusp images of B2045+265 -- regarded as the strongest case of the violation of the cusp relation (i.e. the sum of the magnifications of the three cusp images add to zero) -- show extrinsic variations in their flux-ratios up to ~40 percent peak-to-peak on time scales of several months. Its low Galactic latitude of b=-10 degree and a line-of-sight toward the Cygnus superbubble region suggest that Galactic scintillation is the most likely cause. The cusp images of B1422+231 at b=+69 degree do not show strong extrinsic variability. Galactic scintillation can therefore cause significant scatter in the cusp and fold relations of some radio lens systems (up to 10 percent rms), even though these relations remain violated when averaged over a <~1 year time baseline.

L. V. E. Koopmans; A. Biggs; R. D. Blandford; I. W. A. Browne; N. J. Jackson; S. Mao; P. N. Wilkinson; A. G. de Bruyn; J. Wambsganss

2003-02-11T23:59:59.000Z

477

Implications of Wide-Area Geographic Diversity for Short- Term Variability of Solar Power  

SciTech Connect

Worldwide interest in the deployment of photovoltaic generation (PV) is rapidly increasing. Operating experience with large PV plants, however, demonstrates that large, rapid changes in the output of PV plants are possible. Early studies of PV grid impacts suggested that short-term variability could be a potential limiting factor in deploying PV. Many of these early studies, however, lacked high-quality data from multiple sites to assess the costs and impacts of increasing PV penetration. As is well known for wind, accounting for the potential for geographic diversity can significantly reduce the magnitude of extreme changes in aggregated PV output, the resources required to accommodate that variability, and the potential costs of managing variability. We use measured 1-min solar insolation for 23 time-synchronized sites in the Southern Great Plains network of the Atmospheric Radiation Measurement program and wind speed data from 10 sites in the same network to characterize the variability of PV with different degrees of geographic diversity and to compare the variability of PV to the variability of similarly sited wind. The relative aggregate variability of PV plants sited in a dense 10 x 10 array with 20 km spacing is six times less than the variability of a single site for variability on time scales less than 15-min. We find in our analysis of wind and PV plants similarly sited in a 5 x 5 grid with 50 km spacing that the variability of PV is only slightly more than the variability of wind on time scales of 5-15 min. Over shorter and longer time scales the level of variability is nearly identical. Finally, we use a simple approximation method to estimate the cost of carrying additional reserves to manage sub-hourly variability. We conclude that the costs of managing the short-term variability of PV are dramatically reduced by geographic diversity and are not substantially different from the costs for managing the short-term variability of similarly sited wind in this region.

Mills, Andrew; Wiser, Ryan

2010-08-23T23:59:59.000Z

478

Variability of Raindrop Size Distributions in a Squall Line and Implications for Radar Rainfall Estimation  

Science Conference Proceedings (OSTI)

The intrastorm variability of raindrop size distributions as a source of uncertainty in single-parameter and dual-parameter radar rainfall estimates is studied using time series analyses of disdrometer observations. Two rain-rate (R) estimators ...

Remko Uijlenhoet; Matthias Steiner; James A. Smith

2003-02-01T23:59:59.000Z

479

Recent Climate Variability in Antarctica from Satellite-Derived Temperature Data  

Science Conference Proceedings (OSTI)

Recent Antarctic climate variability on month-to-month to interannual time scales is assessed through joint analysis of surface temperatures from satellite thermal infrared observations (TIR) and passive microwave brightness temperatures (TB). ...

David P. Schneider; Eric J. Steig; Josefino C. Comiso

2004-04-01T23:59:59.000Z

480

Changes in Interannual Variability and Decadal Potential Predictability under Global Warming  

Science Conference Proceedings (OSTI)

Global warming will result in changes in mean temperature and precipitation distributions and is also expected to affect interannual and longer time-scale internally generated variability as a consequence of changes in climate processes and ...

G. J. Boer

2009-06-01T23:59:59.000Z

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