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


1

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

E-Print Network (OSTI)

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

Grizzle, Jessy W.

2

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

E-Print Network (OSTI)

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

Matthews, Jeffrey A., 1970-

2004-01-01T23:59:59.000Z

3

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

E-Print Network (OSTI)

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

4

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

E-Print Network (OSTI)

Airpath Control of a SI Engine with Variable Valve Timing Actuators Thomas Leroy, Jonathan Chauvin with Variable Valve Timing (VVT) actuators. VVT devices are used to produce internal exhaust gas recirculation actuators affect the fresh air charge in the cylinders. This has an impact on the torque output (leading

5

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

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

Discusses development of advanced variable valve actuation system to enable high efficiency combustion highlighting advances to improving system packaging while reducing cost

6

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

DOE Patents (OSTI)

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

Wiles, Matthew A.; Marriot, Craig D

2013-07-02T23:59:59.000Z

7

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

E-Print Network (OSTI)

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

8

Diagnostic for two-mode variable valve activation device  

DOE Patents (OSTI)

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

Fedewa, Andrew M

2014-01-07T23:59:59.000Z

9

Production-Intent Lost-Motion Variable Valve Actuation Systems  

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

Variable valve actuation with on/off IEGR pre-bump is an enabling technology for HCCI, PCCI, LTC and other advanced combustion techniques, and designs for production-intent equipment have been developed

10

Estimation and Control of Diesel Engine Processes Utilizing Variable Intake Valve Actuation  

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

Air handling system model for multi-cylinder variable geometry turbocharged diesel engine with cooled EGR and flexible intake valve actuation developed to capture dynamic effects of gas exchange actuators

11

Valve  

DOE Patents (OSTI)

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

Cho, Nakwon (Knoxville, TN)

1980-01-01T23:59:59.000Z

12

Variable Valve Actuation for Advanced Mode Diesel Combustion...  

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

More Documents & Publications E85 Optimized Engine through Boosting, Spray Optimized GDi, VCR and Variable Valvetrain Ignition Control for HCCI E85 Optimized Engine through...

13

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

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

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

14

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

E-Print Network (OSTI)

Towards Real-Time and Memory Efficient Predictions of Valve States in Diesel Engines Philippe Komma phase complexity while retaining good generalization performance. I. INTRODUCTION In automotive engines T¨ubingen, Germany {philippe.komma, andreas.zell}@uni-tuebingen.de system for a diesel engine

Zell, Andreas

15

Depressurization valve  

DOE Patents (OSTI)

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

Skoda, G.I.

1989-03-28T23:59:59.000Z

16

TimeVariable Photo-Evaporation of  

E-Print Network (OSTI)

TimeVariable Photo-Evaporation of Protoplanetary Disks Henry Throop (SwRI) John Bally (U. Colorado) #12;Takeaway: Photo-evaporation alters the disk structure in essentially unpredictable ways, because for disks formed at the same time in the same cluster. #12;30 Doradus: 100+ O/B stars Photo

Throop, Henry

17

Safety valve  

DOE Patents (OSTI)

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

Bergman, Ulf C. (Malmoe, SE)

1984-01-01T23:59:59.000Z

18

Time Variability of the "Quiet" Sun Observed  

Science Journals Connector (OSTI)

The Transition Region and Coronal Explorer (TRACE) observed a "quiet-Sun" region on 1999 February 17 from 02:15 UT to 3:00 UT with full resolution (05 pixel size), high cadence (125 s), and deep exposures (65 and 46 s) in the 171 and 195 wavelengths. We start our investigation of the time variability of "quiet-Sun" images with a detailed analysis of instrumental and nonsolar effects, such as orbital temperature variations, filtering of particle radiation spikes, spacecraft pointing drift, and solar rotation tracking. We quantify the magnitude of various noise components (photon Poisson statistics, data digitization, data compression, and readout noise) and establish an upper limit for the data noise level, above which temporal variability can safely be attributed to solar origin. We develop a pattern recognition code that extracts spatiotemporal events with significant variability, yielding a total of 3131 events in 171 and 904 events in 195 . We classify all 904 events detected in 195 according to flarelike characteristics and establish a numerical flare criterion based on temporal, spatial, and dynamic cross-correlation coefficients between the two observed temperatures (0.9 and 1.4 MK). This numerical criterion matches the visual flare classification in 83% of the cases and can be used for automated flare search. Using this flare discrimination criterion we find that only 35% (and 25%) of the events detected in 171 (and 195) represent flarelike events. The discrimination of flare events leads to a frequency distribution of peak fluxes, N(?F) ? ?F-1.830.07 at 195 , which is significantly flatter than the distribution of all events. A sensitive discrimination criterion of flare events is therefore important for microflare statistics and for conclusions on their occurrence rate and efficiency for coronal heating.

Markus J. Aschwanden; Richard W. Nightingale; Ted D. Tarbell; C. J. Wolfson

2000-01-01T23:59:59.000Z

19

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

E-Print Network (OSTI)

MOTION PLANNING CONTROL OF THE AIRPATH OF AN S.I. ENGINE WITH VALVE TIMING ACTUATORS T. Leroy , J, France Abstract: We address the control of the airpath of a turbocharged S.I. engine equipped with Variable Valve Timing actuators (VVT). Compared to standard configurations, the engine does not possess any

20

An electromechanical valve drive incorporating a nonlinear mechanical transformer  

E-Print Network (OSTI)

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

Chang, Woo Sok, 1964-

2003-01-01T23:59:59.000Z

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

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

22

Check valve  

DOE Patents (OSTI)

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

Upton, H.A.; Garcia, P.

1999-08-24T23:59:59.000Z

23

Check valve  

DOE Patents (OSTI)

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

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

1999-08-24T23:59:59.000Z

24

Time Variability of the "Quiet" Sun Observed  

Science Journals Connector (OSTI)

We present a detailed analysis of the geometric and physical parameters of 281 EUV nanoflares, simultaneously detected with the TRACE telescope in the 171 and 195 wavelengths. The detection and discrimination of these flarelike events is detailed in the first paper in this series. We determine the loop length l, loop width w, emission measure EM, the evolution of the electron density ne(t) and temperature Te(t), the flare decay time ?decay, and calculate the radiative loss time ?loss, the conductive loss time ?cond, and the thermal energy Eth. The findings are as follows: (1) EUV nanoflares in the energy range of 1024-1026 ergs represent miniature versions of larger flares observed in soft X-rays (SXR) and hard X-rays (HXR), scaled to lower temperatures (Te 2 MK), lower densities (ne 109 cm-3), and somewhat smaller spatial scales (l ? 2-20 Mm). (2) The cooling time ?decay is compatible with the radiative cooling time ?rad, but the conductive cooling timescale ?cond is about an order of magnitude shorter, suggesting repetitive heating cycles in time intervals of a few minutes. (3) The frequency distribution of thermal energies of EUV nanoflares, N(E) ? 10-46(E/1024)-1.8 (s-1 cm-2 ergs-1) matches that of SXR microflares in the energy range of 1026-1029, and exceeds that of nonthermal energies of larger flares observed in HXR by a factor of 3-10 (in the energy range of 1029-1032 ergs). Discrepancies of the power-law slope with other studies, which report higher values in the range of a = 2.0-2.6 (Krucker & Benz; Parnell & Jupp), are attributed to methodical differences in the detection and discrimination of EUV microflares, as well as to different model assumptions in the calculation of the electron density. Besides the insufficient power of nanoflares to heat the corona, we find also other physical limits for nanoflares at energies 1024 ergs, such as the area coverage limit, the heating temperature limit, the lower coronal density limit, and the chromospheric loop height limit. Based on these quantitative physical limitations, it appears that coronal heating requires other energy carriers that are not luminous in EUV, SXR, and HXR.

Markus J. Aschwanden; Ted D. Tarbell; Richard W. Nightingale; Carolus J. Schrijver; Alan Title; Charles C. Kankelborg; Piet Martens; Harry P. Warren

2000-01-01T23:59:59.000Z

25

A Multichannel, Variable?Threshold, Time?Sequence Recorder  

Science Journals Connector (OSTI)

The analysis and design of a ten?channel variable?threshold time?sequence recorder that uses TTL is presented. Channel?to?channel time resolution is ? 250 nsec and risetime is ? 6 usec for a 2?V p?p signal. Although the recorder is designed to examine the flux?jump phenomenon in large superconducting magnets it has application wherever variable?threshold time?sequencing is required.

Mark L. McKinstry

1973-01-01T23:59:59.000Z

26

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

27

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

28

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

29

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

30

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

31

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

32

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

E-Print Network (OSTI)

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

Kassakian, John G.

33

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

34

Time series data mining for the Gaia variability analysis  

E-Print Network (OSTI)

Gaia is an ESA cornerstone mission, which was successfully launched December 2013 and commenced operations in July 2014. Within the Gaia Data Processing and Analysis consortium, Coordination Unit 7 (CU7) is responsible for the variability analysis of over a billion celestial sources and nearly 4 billion associated time series (photometric, spectrophotometric, and spectroscopic), encoding information in over 800 billion observations during the 5 years of the mission, resulting in a petabyte scale analytical problem. In this article, we briefly describe the solutions we developed to address the challenges of time series variability analysis: from the structure for a distributed data-oriented scientific collaboration to architectural choices and specific components used. Our approach is based on Open Source components with a distributed, partitioned database as the core to handle incrementally: ingestion, distributed processing, analysis, results and export in a constrained time window.

Nienartowicz, Krzysztof; Guy, Leanne; Holl, Berry; Lecoeur-Tabi, Isabelle; Mowlavi, Nami; Rimoldini, Lorenzo; Ruiz, Idoia; Sveges, Maria; Eyer, Laurent

2014-01-01T23:59:59.000Z

35

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

36

Essays on Bayesian Time Series and Variable Selection  

E-Print Network (OSTI)

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

De, Debkumar

2014-05-08T23:59:59.000Z

37

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

DOE Patents (OSTI)

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

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

2012-04-17T23:59:59.000Z

38

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

39

Valve for controlling solids flow  

DOE Patents (OSTI)

A fluidized solids control valve is disclosed that is particularly well adapted for use with a flow of coal or char that includes both large particles and fines. The particles may or may not be fluidized at various times during the operation. The valve includes a tubular body that terminates in a valve seat covered by a normally closed closure plate. The valve body at the seat and the closure plate is provided with aligned longitudinal slots that receive a pivotally supported key plate. The key plate is positionable by an operator in inserted, intermediate and retracted positions respecting the longitudinal slot in the valve body. The key plate normally closes the slot within the closure plate but is shaped and aligned obliquely to the longitudinal slot within the valve body to provide progressively increasing slot openings between the inserted and retracted positions. Transfer members are provided between the operator, key plate and closure plate to move the closure plate into an open position only when the key plate is retracted from the longitudinal slot within the valve body.

Feldman, David K. (Fairlawn, NJ)

1980-01-01T23:59:59.000Z

40

Variable structure control of linear time-delay uncertain singular system  

Science Journals Connector (OSTI)

Synthesis and designing of variable structure controller for time-delay singular uncertain system are studied. Firstly, the system is decomposed into two low dimensional subsystems. Secondly, switching function and variable structure controller are ... Keywords: VSC, controller design, singular systems, switching function, time delay, uncertain systems, variable structure control

Jifeng Guo; Cunchen Gao

2009-04-01T23:59:59.000Z

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


41

Remote actuated valve implant  

SciTech Connect

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

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

2014-02-25T23:59:59.000Z

42

Bellows sealed plug valve  

DOE Patents (OSTI)

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

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

1990-01-01T23:59:59.000Z

43

Valves: Corrosion and maintenance  

SciTech Connect

A mill setting is without doubt a harsh, demanding environment for valves. In a polling of valve suppliers, several areas were identified as the most corrosive to valves, particularly chemical pulping, bleaching, chemical recovery, and waste-water treatment. In some uses, a valve may only last 12-18 months. Depending on the alloy and seat material used, the life expectancy can also exceed 10 years in some applications. This survey of valve manufacturers gives basic tips on selecting, protecting, and maintaining valves.

Meadows, D.G.

1993-08-01T23:59:59.000Z

44

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

45

Overflow control valve  

DOE Patents (OSTI)

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

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

1984-07-24T23:59:59.000Z

46

Cycle time variability for a network under two queueing disciplines  

E-Print Network (OSTI)

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

Vasquez Pariente, Marta Irene

1996-01-01T23:59:59.000Z

47

VARIABILITY OF SOLAR RADIATION DATA OVER SHORT TIME INTERVALS Frank Vignola  

E-Print Network (OSTI)

radiation values obtained from models utilizing satellite or cloud cover observation data with solarVARIABILITY OF SOLAR RADIATION DATA OVER SHORT TIME INTERVALS Frank Vignola Department of Physics to evaluate satellite and cloud cover models, it is useful to understand the short-term variability of solar

Oregon, University of

48

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

E-Print Network (OSTI)

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

Hirsch, Edward A.

49

Variable neighborhood search algorithm for heterogeneous traveling repairmen problem with time windows  

Science Journals Connector (OSTI)

The focus of this paper is generalized traveling repairman problem (TRP), a special case of the well known and well studied traveling salesman problem (TSP). Because of its specific objective function, that minimizes the sum of overall time all clients ... Keywords: Heterogeneous traveling repairmen problem with time windows, Operations planning, Variable neighborhood search

Nenad Bjeli?; Milorad Vidovi?; Draen Popovi?

2013-11-01T23:59:59.000Z

50

Energy Savings Potential of Process Control Valve Replacement  

E-Print Network (OSTI)

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

Holzenthal, L. Jr.

51

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

52

Mud saver valve  

SciTech Connect

This patent describes a mud saver valve for retaining drilling fluid in the kelly of a rotary drilling rig. It comprises: a kelly sub defining an open-ended elongated body having threaded ends for forming a connection between the kelly and a drill pipe string; an enlarged bore formed in said elongated body; a tubular body received within said enlarged bore of said elongated body, said tubular body including an enlarged portion defining a shoulder for engagement with a shoulder formed in said elongated body; hollow piston means axially disposed within said tubular body. The piston means being axially movable relative to said tubular body and defining a fluid passage therethrough; valve means removably mounted within said tubular body. The valve means cooperating with said piston means to normally close the fluid passage through said piston means, wherein said valve means is movable between a first and second position; a stop member removably connected to said tubular body. The stop member including a first internal circumferential tapered shoulder for limiting downward movement of said valve means; and means for urging said piston means into engagement with said valve means.

Baugh, B.F.

1990-02-13T23:59:59.000Z

53

Long-Time Dynamics of Variable Coefficient mKdV Solitary Waves  

E-Print Network (OSTI)

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

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

2005-03-08T23:59:59.000Z

54

Continuous-time random-walk model of transport in variably saturated heterogeneous porous media  

Science Journals Connector (OSTI)

We propose a unified physical framework for transport in variably saturated porous media. This approach allows fluid flow and solute migration to be treated as ensemble averages of fluid and solute particles, respectively. We consider the cases of homogeneous and heterogeneous porous materials. Within a fractal mobile-immobile continuous time random-walk framework, the heterogeneity will be characterized by algebraically decaying particle retention times. We derive the corresponding (nonlinear) continuum-limit partial differential equations and we compare their solutions to Monte Carlo simulation results. The proposed methodology is fairly general and can be used to track fluid and solutes particles trajectories for a variety of initial and boundary conditions.

Andrea Zoia; Marie-Christine Nel; Andrea Cortis

2010-03-04T23:59:59.000Z

55

THE GALEX TIME DOMAIN SURVEY. I. SELECTION AND CLASSIFICATION OF OVER A THOUSAND ULTRAVIOLET VARIABLE SOURCES  

SciTech Connect

We present the selection and classification of over a thousand ultraviolet (UV) variable sources discovered in {approx}40 deg{sup 2} of GALEX Time Domain Survey (TDS) NUV images observed with a cadence of 2 days and a baseline of observations of {approx}3 years. The GALEX TDS fields were designed to be in spatial and temporal coordination with the Pan-STARRS1 Medium Deep Survey, which provides deep optical imaging and simultaneous optical transient detections via image differencing. We characterize the GALEX photometric errors empirically as a function of mean magnitude, and select sources that vary at the 5{sigma} level in at least one epoch. We measure the statistical properties of the UV variability, including the structure function on timescales of days and years. We report classifications for the GALEX TDS sample using a combination of optical host colors and morphology, UV light curve characteristics, and matches to archival X-ray, and spectroscopy catalogs. We classify 62% of the sources as active galaxies (358 quasars and 305 active galactic nuclei), and 10% as variable stars (including 37 RR Lyrae, 53 M dwarf flare stars, and 2 cataclysmic variables). We detect a large-amplitude tail in the UV variability distribution for M-dwarf flare stars and RR Lyrae, reaching up to |{Delta}m| = 4.6 mag and 2.9 mag, respectively. The mean amplitude of the structure function for quasars on year timescales is five times larger than observed at optical wavelengths. The remaining unclassified sources include UV-bright extragalactic transients, two of which have been spectroscopically confirmed to be a young core-collapse supernova and a flare from the tidal disruption of a star by dormant supermassive black hole. We calculate a surface density for variable sources in the UV with NUV < 23 mag and |{Delta}m| > 0.2 mag of {approx}8.0, 7.7, and 1.8 deg{sup -2} for quasars, active galactic nuclei, and RR Lyrae stars, respectively. We also calculate a surface density rate in the UV for transient sources, using the effective survey time at the cadence appropriate to each class, of {approx}15 and 52 deg{sup -2} yr{sup -1} for M dwarfs and extragalactic transients, respectively.

Gezari, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)] [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Martin, D. C.; Forster, K.; Neill, J. D.; Morrissey, P.; Wyder, T. K. [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)] [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Huber, M.; Burgett, W. S.; Chambers, K. C.; Kaiser, N.; Magnier, E. A.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)] [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Heckman, T.; Bianchi, L. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)] [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Neff, S. G. [Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Seibert, M. [Observatories of the Carnegie Institute of Washington, Pasadena, CA 90095 (United States)] [Observatories of the Carnegie Institute of Washington, Pasadena, CA 90095 (United States); Schiminovich, D. [Department of Astronomy, Columbia University, New York, NY 10027 (United States)] [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Price, P. A., E-mail: suvi@astro.umd.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-03-20T23:59:59.000Z

56

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

57

Sizing safety valve vent pipes for saturated steam  

SciTech Connect

A generalized procedure based on pressure and entropy as independent variables is used to calculate choked flow conditions at the valve orifice, valve pipe outlet and vent pipe outlet. At the third location, the results are independent of whether flow in the vent pipe is supersonic or subsonic. An integral method is used to calculate the vent pipe length required to choke the flow. 16 refs.

Brandmaier, H.E.

1982-01-01T23:59:59.000Z

58

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

59

Valve stem and packing assembly  

DOE Patents (OSTI)

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

Wordin, John J. (Bingham County, ID)

1991-01-01T23:59:59.000Z

60

Reducing pressure loss of large diameter check valves  

SciTech Connect

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

NONE

1997-09-01T23:59:59.000Z

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

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

62

Classification of heart valve condition using acoustic measurements  

SciTech Connect

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

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

1994-11-15T23:59:59.000Z

63

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

E-Print Network (OSTI)

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

Snchez-Martnez, Gabriel Eduardo

2013-01-01T23:59:59.000Z

64

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

E-Print Network (OSTI)

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

Ravindran, Binoy

65

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

SciTech Connect

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

66

Variable interval time/temperature (VITT) defrost-control-system evaluation  

SciTech Connect

Two variable-interval-time/temperature (VITT) heat pump defrost control systems are analyzed to determine if systems manufactured by Honeywell and Ranco qualify for credit for heat pumps with demand defrost control. The operation of the systems is described. VITT controls are not demand defrost control systems but utilize demand defrost control as backup systems in most Ranco models and all Honeywell models. The evaluations and results, intended to provide DOE information in making its determinations regarding credits for the control systems are discussed. The evaluation methodology utilizes a modified version of the Heat Pump Seasonal Performance Model (HPSPM) and the important modifications are discussed in Appendix A. Appendix B contains a detailed listing and discussion of the HPSPM output. (MCW)

None

1980-08-12T23:59:59.000Z

67

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

SciTech Connect

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

Lamoreaux, Steve (LANL) [LANL

2005-11-07T23:59:59.000Z

68

Fast-acting valve and uses thereof  

DOE Patents (OSTI)

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

Meyer, James A. (Espanola, NM)

1982-01-01T23:59:59.000Z

69

Fast-acting valve and uses thereof  

DOE Patents (OSTI)

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

Meyer, J.A.

1980-05-16T23:59:59.000Z

70

Interannual Atmospheric Variability Affects Continental Ice Sheet Simulations on Millennial Time Scales  

Science Journals Connector (OSTI)

To inform the ongoing development of earth system models that aim to incorporate interactive ice, the potential impact of interannual variability associated with synoptic variability and El NioSouthern Oscillation (ENSO) at the Last Glacial ...

Michael S. Pritchard; Andrew B. G. Bush; Shawn J. Marshall

2008-11-01T23:59:59.000Z

71

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

72

Internal combustion engine intake valve  

SciTech Connect

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

Mosler, W.B.

1988-10-25T23:59:59.000Z

73

SOLAR CYCLE VARIABILITY AND SURFACE DIFFERENTIAL ROTATION FROM Ca II K-LINE TIME SERIES DATA  

SciTech Connect

Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period {approx} 11 yr), (b) quasi-periodic variations (periods {approx} 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range {approx}0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak{sub m}on/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters.

Scargle, Jeffrey D.; Worden, Simon P. [NASA Ames Research Center, Moffett Field, CA, 94035 (United States); Keil, Stephen L. [National Solar Observatory, P.O. Box 57, Sunspot, NM 88349 (United States)

2013-07-01T23:59:59.000Z

74

Software Enabled Virtually Variable Displacement Pumps -Theoretical and Experimental Studies  

E-Print Network (OSTI)

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

Li, Perry Y.

75

Fig. 1. Comparison of search times on original logistics problems. Fig 2. Number of variables in logistics formulas after simplification.  

E-Print Network (OSTI)

Fig. 1. Comparison of search times on original logistics problems. Fig 2. Number of variables in logistics formulas after simplification. Fig. 3. Number of clauses in logistics formulas after number of clauses log.a log.b log.c #12; Fig. 4: Solution times for walksat on logistics with different

Kautz, Henry

76

Redesigned recycle valves abate compressor vibration  

SciTech Connect

New recycle valves installed in 1994 on the compressors in the East Brae field in the North Sea corrected the noise and vibration problem that damaged the original valves shortly after commissioning the platform. The original recycle valves, especially on the second-stage compressors, showed severe damage. The paper describes the Brae field, the recycle system, recycle valves, operations, the new valve design, noise and vibration, and valve actuators.

Laing, D.E. [Marathon Oil U.K. Ltd., Aberdeen (United Kingdom); Miller, H.L.; McCaskill, J.W. [Engineering Control Components Inc., Rancho Santa Margarita, CA (United States)

1995-06-05T23:59:59.000Z

77

Surge-damping vacuum valve  

DOE Patents (OSTI)

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

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

1980-01-01T23:59:59.000Z

78

Control valve for solar heating systems  

SciTech Connect

A control valve for a solar heating system is disclosed. The valve has a valve body which defines four chambers disposed end to end. A valve operating rod is movable axially through all four chambers under motor control and carries a valve member for directing liquid through the valve. In one position of the valve member, incoming liquid is directed to an outlet for connection to a solar collector and liquid returning from the collector can flow through the valve body and back to the swimming pool. In the other position of the valve member, the liquid bypasses the collector and is directed back to the pool while liquid in the collector drains back into the valve body through the outlet and is removed by suction from a drain-down chamber in the valve body.

Stewart, J.M.

1981-12-29T23:59:59.000Z

79

Annular flow control safety valve  

SciTech Connect

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

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

1981-06-16T23:59:59.000Z

80

Relevance of valve overlap for meeting Euro 5 soot emissions requirements during load transient process in heavy duty diesel engines  

Science Journals Connector (OSTI)

This work describes the influence on performance and soot emissions of using different valve overlap camshafts during load transient processes in a heavy duty (HD) diesel engine equipped with a variable geometry turbine (VGT) in its turbocharger and a selective catalyst reactor (SCR) in the exhaust line. Based on the results of experiments and calculations, in this paper a description is given of how the valve timing affects the instantaneous exhaust and intake pressure, the short-circuit of the air mass flow, the prejudicial backflows, the performance of the turbine and hence the general performance and pollutant emissions of a VGT equipped HD diesel engine during a transient process. The paper concludes that very low or no overlap is imperative if a VGT is used to meet forthcoming pollutant emissions restrictions and to improve the transient response of HD turbocharged diesel engines.

J. Galindo; J.R. Serrano; F. Vera; C. Cervello; M. Lejeune

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.


81

Controls on spatial and temporal variability in Northern Hemisphere terrestrial snow melt timing, 1979-2012  

Science Journals Connector (OSTI)

Spring snow melt onset has occurred earlier across much of Northern Hemisphere lands in the last four decades. Understanding the mechanisms driving spring melt has remained a challenge, particularly in its spatial and temporal variability. Here, ...

J. R. Mioduszewski; A. K. Rennermalm; D. A. Robinson; L. Wang

82

Cavitation guide for control valves  

SciTech Connect

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

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

1993-04-01T23:59:59.000Z

83

Steam Turbine Control Valve Noise  

Science Journals Connector (OSTI)

Although noise problems with steam turbine control valves have existed before they have become more prominent with nuclear turbines whose valves range to 20 in. in diameter. Our first?generation nuclear control valves were unacceptably noisy when operating under chocked conditions. These noise levels have been ameliorated by incorporation of a valve cage with numerous small holes. Rational design rules for this dispersive muffler have been developed from published multiple?jet noise data and improved through our own tests. However we are also evaluating other low?noise valve configurations which are consistent with turbine requirements. The approach we are developing is to investigate the internal aerodynamic noisegeneration in small air model tests and to combine this with measurements of pipe?wall transmission characteristics (being reported separately) to predict externally radiated noise. These predictions will be checked in a new steam test facility for complete scale?model valves. The small air tests show that acoustic efficiencies of throttling valve flows tend to vary with third power of Mach number when exhausting into space and with a lesser power when enclosed in a downstream pipe. At some pressure ratios narrow?band spikes appear in the spectrum and for some configurations step changes in sound power are associated with transitions in flow regimes.

Frank J. Heymann; Michael A. Staiano

1973-01-01T23:59:59.000Z

84

Heart valve tissue engineering Frank Baaijens  

E-Print Network (OSTI)

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

Stavroulakis, Georgios E.

85

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

86

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

SciTech Connect

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

87

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

E-Print Network (OSTI)

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

88

Variable rate spreader for real-time spot-application of granular fertilizer in wild blueberry  

Science Journals Connector (OSTI)

The commercial variable rate (VR) fertilizer spreader can change fertilizer rates in different management zones using global positioning system (GPS) guided prescription maps. The VR fertilizer spreader allows the independent control only on half of ... Keywords: Controller, Digital photography, Fertilizer, Sensing and control system, Spot-application, Wild blueberry

Hassan S. Chattha; Qamar U. Zaman; Young K. Chang; Scott Read; Arnold W. Schumann; Gordon R. Brewster; Aitazaz A. Farooque

2014-01-01T23:59:59.000Z

89

Friction and Wear Reduction in Diesel Engine Valve Trains | Department...  

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

More Documents & Publications Mechanisms of Oxidation-Enhanced Wear in Diesel Exhaust Valves Materials for Advanced Engine Valve Train Materials for Advanced Engine Valve Train...

90

Development of Lashless Valve Train Technology | Department of...  

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

Lashless Valve Train Technology Development of Lashless Valve Train Technology This poster covers Jacobs history of lashless valve train efforts, design, simulation, engine...

91

Noninvasive valve monitor using alternating electromagnetic field  

DOE Patents (OSTI)

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

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

1993-01-01T23:59:59.000Z

92

Annular flow diverter valve  

DOE Patents (OSTI)

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

Rider, Robert L. (Walkersville, MD)

1980-01-01T23:59:59.000Z

93

Strategy for reducing the length and variability of aircraft lead time  

E-Print Network (OSTI)

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

Bielat, Brendon (Brendon Michael)

2010-01-01T23:59:59.000Z

94

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

E-Print Network (OSTI)

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

Yao, Bin

95

Stellar variability on time-scales of minutes: results from the first 5 years of the Rapid Temporal Survey (RATS)  

E-Print Network (OSTI)

The Rapid Temporal Survey (RATS) explores the faint, variable sky. Our observations search a parameter space which, until now, has never been exploited from the ground. Our strategy involves observing the sky close to the Galactic plane with wide-field CCD cameras. An exposure is obtained approximately every minute with the total observation of each field lasting around 2 hours. In this paper we present the first 6 epochs of observations which were taken over 5 years from 2003--2008 and cover over 31 square degrees of which 16.2 is within 10{\\deg} of the Galactic plane. The number of stars contained in these data is over 3.0 x10^6. We have developed a method of combining the output of two variability tests in order to detect variability on time-scales ranging from a few minutes to a few hours. Using this technique we find 1.2 x 10^5 variables -- equal to 4.1 per cent of stars in our data. Follow-up spectroscopic observations have allowed us to identify the nature of a fraction of these sources. These include ...

Barclay, Thomas; Hakala, Pasi; Napiwotzki, Ralf; Nelemans, Gijs; Potter, Stephen; Todd, Ian

2011-01-01T23:59:59.000Z

96

Active combustion flow modulation valve  

DOE Patents (OSTI)

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

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

2013-09-24T23:59:59.000Z

97

American Valve: Order (2010-CW-1411)  

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

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

98

Self Contained Temperature Actuated Control Valves  

E-Print Network (OSTI)

Ogontz Controls Company, P.O. Box 479, Willow Grove, Pennsylvania, 19090. FREEZ AND SCALD PROTECTION OUTDOOR EMERGENCY SHOWER = t' ",. 362 ESL-IE-79-04-39 Proceedings from the First Industrial Energy Technology Conference Houston, TX, April 22... control valves and surface temperature control valves (to provide setqp and freeze protection), fluid sensing control valves, air fluid sensing control valves, safety shower val~es (to provide both freeze and scald protection) and condensate freeze...

Pirkle, F.

1979-01-01T23:59:59.000Z

99

Lockout housing and sleeve for safety valve  

SciTech Connect

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

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

1992-07-07T23:59:59.000Z

100

Fast-acting valve actuator  

DOE Patents (OSTI)

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

Cho, Nakwon (Knoxville, TN)

1980-01-01T23:59:59.000Z

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


101

CONTROL VALVE TESTING PROCEDURES AND EQUATIONS  

E-Print Network (OSTI)

APPENDIX A CONTROL VALVE TESTING PROCEDURES AND EQUATIONS FOR LIQUID FLOWS #12;APPENDIX A CONTROL VALVE TESTING PROCEDURES AND EQUATIONS FOR LIQUID FLOWS 2 Cv Q P Sg net gpm net = / Cv = Q P / Sg 75 in this report is per Instrument Society of America S39.2 testing specifications for control valves. The main

Rahmeyer, William J.

102

Dynamic Testing of Check Valves William Rahmeyer  

E-Print Network (OSTI)

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

Rahmeyer, William J.

103

Valve for fuel pin loading system  

DOE Patents (OSTI)

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

Christiansen, D.W.

1984-01-01T23:59:59.000Z

104

Valve for fuel pin loading system  

DOE Patents (OSTI)

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

Christiansen, David W. (Kennewick, WA)

1985-01-01T23:59:59.000Z

105

Rapid timing studies of black hole binaries in Optical and X-rays: correlated and non-linear variability  

SciTech Connect

In a fast multi-wavelength timing study of black hole X-ray binaries (BHBs), we have discovered correlated optical and X-ray variability in the low/hard state of two sources: GX 339-4 and SWIFT J1753.5-0127. After XTE J1118+480, these are the only BHBs currently known to show rapid (sub-second) aperiodic optical flickering. Our simultaneous VLT/Ultracam and RXTE data reveal intriguing patterns with characteristic peaks, dips and lags down to very short timescales. Simple linear reprocessing models can be ruled out as the origin of the rapid, aperiodic optical power in both sources. A magnetic energy release model with fast interactions between the disk, jet and corona can explain the complex correlation patterns. We also show that in both the optical and X-ray light curves, the absolute source variability r.m.s. amplitude linearly increases with flux, and that the flares have a log-normal distribution. The implication is that variability at both wavelengths is not due to local fluctuations alone, but rather arises as a result of coupling of perturbations over a wide range of radii and timescales. These 'optical and X-ray rms-flux relations' thus provide new constraints to connect the outer and inner parts of the accretion flow, and the jet.

Gandhi, P. [RIKEN Cosmic Radiation Laboratory, 2-1 Hirosawa, Wako, Saitama 351-0198 Japan (Japan); Dhillon, V. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Durant, M.; Shahbaz, T. [Instituto de Astrofisica de Canarias, La Laguna, E38205 Tenerife (Spain); Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Makishima, K. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Marsh, T. R. [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL (United Kingdom); Miller, J. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Spruit, H. C. [Max-Planck-Institut fuer Astrophysik, Postfach 1317, 85741 Garching (Germany)

2010-07-15T23:59:59.000Z

106

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

SciTech Connect

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

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

2014-01-01T23:59:59.000Z

107

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

108

Sizing sliding gate valves for steam service  

SciTech Connect

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

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

1995-11-06T23:59:59.000Z

109

Evaluation of silicon-nitride ceramic valves.  

SciTech Connect

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

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

2008-01-01T23:59:59.000Z

110

Variability of a stellar corona on a time scale of days  

E-Print Network (OSTI)

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

Nordon, Raanan; Drake, Stephen A

2012-01-01T23:59:59.000Z

111

Rapid 3D printing of anatomically accurate and mechanically heterogeneous aortic valve hydrogel scaffolds  

Science Journals Connector (OSTI)

The aortic valve exhibits complex three-dimensional (3D) anatomy and heterogeneity essential for the long-term efficient biomechanical function. These are, however, challenging to mimic in de novo engineered living tissue valve strategies. We present a novel simultaneous 3D printing/photocrosslinking technique for rapidly engineering complex, heterogeneous aortic valve scaffolds. Native anatomic and axisymmetric aortic valve geometries (root wall and tri-leaflets) with 1222mm inner diameters (ID) were 3D printed with poly-ethylene glycol-diacrylate (PEG-DA) hydrogels (700 or 8000 MW) supplemented with alginate. 3D printing geometric accuracy was quantified and compared using Micro-CT. Porcine aortic valve interstitial cells (PAVIC) seeded scaffolds were cultured for up to 21days. Results showed that blended PEG-DA scaffolds could achieve over tenfold range in elastic modulus (5.30.9 to 74.61.5 kPa). 3D printing times for valve conduits with mechanically contrasting hydrogels were optimized to 14 to 45min, increasing linearly with conduit diameter. Larger printed valves had greater shape fidelity (93.32.6, 85.12.0 and 73.35.2% for 22, 17 and 12mm ID porcine valves; 89.14.0, 84.15.6 and 66.65.2% for simplified valves). PAVIC seeded scaffolds maintained near 100% viability over 21days. These results demonstrate that 3D hydrogel printing with controlled photocrosslinking can rapidly fabricate anatomical heterogeneous valve conduits that support cell engraftment.

L A Hockaday; K H Kang; N W Colangelo; P Y C Cheung; B Duan; E Malone; J Wu; L N Girardi; L J Bonassar; H Lipson; C C Chu; J T Butcher

2012-01-01T23:59:59.000Z

112

Valve assembly for use with high temperature and high pressure fluids  

DOE Patents (OSTI)

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

De Feo, Angelo (Totowa, NY)

1982-01-01T23:59:59.000Z

113

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

114

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

SciTech Connect

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

Gross, Robert; Harris, Stephen

2007-08-01T23:59:59.000Z

115

Michigan: General Motors Optimizes Engine Valve Technology  

Office of Energy Efficiency and Renewable Energy (EERE)

An EERE-supported effort to increase energy efficiency, while maintaining low emissions, has resulted in new engine valve technology on the 2014 Chevrolet Impala.

116

Install Removable Insulation on Valves and Fittings  

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

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

117

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

Energy Savers (EERE)

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

118

Key valves prioritization study. Final report  

SciTech Connect

Key valves, installed in nuclear power plants, are those valves in which a malfunction can result in a shut down, in a reduction in power generation level, or in the extension of planned outages. Over two thousand Licensee Event Reports (LERs) are evaluated to identify the valve failure events which affected nuclear plant availability. Other data reporting systems are used to supplement the information collected for each event. A data base is established comprising 102 key valve failure events that are identified as the principal case of lost plant availability.

Riddington, J.W.

1984-10-01T23:59:59.000Z

119

D0 Silicon Upgrade: Control Dewar Valve Calculations  

SciTech Connect

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

Rucinski, Russ; /Fermilab

1995-10-20T23:59:59.000Z

120

Variable Circular Collimator in Robotic Radiosurgery: A Time-Efficient Alternative to a Mini-Multileaf Collimator?  

SciTech Connect

Purpose: Compared with many small circular beams used in CyberKnife treatments, beam's eye view-shaped fields are generally more time-efficient for dose delivery. However, beam's eye view-shaping devices, such as a mini-multileaf collimator (mMLC), are not presently available for CyberKnife, although a variable-aperture collimator (Iris, 12 field diameters; 5-60 mm) is available. We investigated whether the Iris can mimic noncoplanar mMLC treatments using a limited set of principal beam orientations (nodes) to produce time-efficient treatment plans. Methods and Materials: The data from 10 lung cancer patients and the beam-orientation optimization algorithm 'Cycle' were used to generate stereotactic treatment plans (3 x 20 Gy) for a CyberKnife virtually equipped with a mMLC. Typically, 10-16 favorable beam orientations were selected from 117 available robot node positions using beam's eye view-shaped fields with uniform fluence. Second, intensity-modulated Iris plans were generated by inverse optimization of nonisocentric circular candidate beams targeted from the same nodes selected in the mMLC plans. The plans were evaluated using the mean lung dose, lung volume receiving {>=}20 Gy, conformality index, number of nodes, beams, and monitor units, and estimated treatment time. Results: The mMLC plans contained an average of 12 nodes and 11,690 monitor units. For a comparable mean lung dose, the Iris plans contained 12 nodes, 64 beams, and 21,990 monitor units. The estimated fraction duration was 12.2 min (range, 10.8-13.5) for the mMLC plans and 18.4 min (range, 12.9-28.5) for the Iris plans. In contrast to the mMLC plans, the treatment time for the Iris plans increased with an increasing target volume. The Iris plans were, on average, 40% longer than the corresponding mMLC plans for small targets (<80 cm{sup 3}) and {<=}121% longer for larger targets. For a comparable conformality index, similar results were obtained. Conclusion: For stereotactic lung irradiation, time-efficient and high-quality plans were obtained for robotic-controlled noncoplanar treatments using a mMLC. Iris is a time-efficient alternative for small targets, with similar or better plan quality.

Water, Steven van de, E-mail: s.vandewater@erasmusmc.nl [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Hoogeman, Mischa S.; Breedveld, Sebastiaan; Nuyttens, Joost J.M.E. [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands); Schaart, Dennis R. [Department of Radiation Detection and Medical Imaging, Delft University of Technology, Delft (Netherlands); Heijmen, Ben J.M. [Department of Radiation Oncology, Erasmus Medical Center-Daniel den Hoed Cancer Center, Rotterdam (Netherlands)

2011-11-01T23:59:59.000Z

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

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

E-Print Network (OSTI)

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

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

2007-01-01T23:59:59.000Z

122

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

SciTech Connect

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

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

1999-06-01T23:59:59.000Z

123

Cylinder valve packing nut studies  

SciTech Connect

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

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

1991-12-31T23:59:59.000Z

124

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

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

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

125

Advanced Materials for Lightweight Valve Train Components | Department...  

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

for Lightweight Valve Train Components Advanced Materials for Lightweight Valve Train Components Presentation from the U.S. DOE Office of Vehicle Technologies "Mega" Merit Review...

126

Characterization of the mitral valve using accelerated wear testing.  

E-Print Network (OSTI)

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

Riggan, Courtney N.

2010-01-01T23:59:59.000Z

127

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

SciTech Connect

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

MORGAN, R.G.

1999-06-23T23:59:59.000Z

128

High speed exhaust gas recirculation valve  

DOE Patents (OSTI)

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

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

2005-01-18T23:59:59.000Z

129

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

130

Minimizing energy losses in control valves  

SciTech Connect

The pulp and paper industry uses massive amounts of energy, but it could reduce its electricity consumption by about 2,000 MW worldwide by simply optimizing the pumping of process liquids. Wasted pumping power can be significantly reduced by sizing pumps and control valves more accurately, and by using new methods of pump and valve selection. Combining the improved control valve's installed flow characteristic with state-of-the-art sizing and simulation programs ensures minimal pressure drop across the control valve without loss of accurate and reliable control in all process conditions. If accurate process condition information is available at the planning stage, even more significant pumping energy savings can be achieved. Moreover, reduced pressure drop across the control valve reduces the likelihood of valve cavitation. This, in turn, reduces the need for noise attenuation, preventing cavitation erosion, and repairing damage. To make the most of the advantages gained by using highly developed control valve sizing and selection programs, closer cooperation between process licensees, process users, and valve manufacturers is also required.

Niemela, I.; Pyotsia, J. (Neles-Jamesbury Oy, Helsinki (Finland))

1994-08-01T23:59:59.000Z

131

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

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

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

132

Whitey SCHe Ball Valves Provide Test Port Isolation  

SciTech Connect

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

MISKA, C.R.

2000-09-15T23:59:59.000Z

133

Whitey SCHe Ball Valves Provide Test Port Isolation  

SciTech Connect

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

MISKA, C.R.

2000-10-19T23:59:59.000Z

134

Pressure compensated flow control valve  

DOE Patents (OSTI)

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

Minteer, Daniel J. (West Richland, WA)

1999-01-01T23:59:59.000Z

135

Torque-Actuated Valves for Microfluidics  

Science Journals Connector (OSTI)

Torque-Actuated Valves for Microfluidics ... While these valves should be widely useful in the field of microfluidics, we demonstrate their use in portable, disposable microfluidic devices. ... Elastomeric polymersespecially poly(dimethylsiloxane) (PDMS)are used widely in microfluidics for several reasons:? (i) ease of fabrication using soft lithography and rapid prototyping;1-3 (ii) ability to incorporate seals, membranes, valves, and switches;4-7 (iii) transparency and compatibility with optical detection;8,9 and (iv) compatibility with water and biological molecules and cells. ...

Douglas B. Weibel; Maarten Kruithof; Scott Potenta; Samuel K. Sia; Andrew Lee; George M. Whitesides

2005-06-15T23:59:59.000Z

136

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

E-Print Network (OSTI)

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

Cammarota, Camillo

137

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

SciTech Connect

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

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

1999-06-01T23:59:59.000Z

138

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

139

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

140

The safety valve and climate policy  

E-Print Network (OSTI)

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

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

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

Project Development Specification for Valve Pit Manifold  

SciTech Connect

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

MCGREW, D.L.

2000-09-28T23:59:59.000Z

142

Analysis of an extremely fast valve opening camless system to improve transient performance in a turbocharged high speed direct injection diesel engine  

Science Journals Connector (OSTI)

This article describes a theoretical study on the performance optimisation of a high speed direct injection turbocharged diesel engine equipped with an electro-hydraulic variable valve actuation 'camless' system. This system provides extremely fast valve opening and closing slopes. Thus, its potential for recovering part of the energy lost in the valves by reducing gas flow sonic conditions in the valve throat has been investigated. This study has been mainly focused on the analysis of engine performance during a load transient evolution, but the full load steady state attained at the end of the load transient has been also discussed. The results of this investigation have confirmed important improvements in engine performance during the load transient owing to less energy being lost across the valves, which directly results in more energy being available in the turbine. This benefit has also been observed at full load steady state conditions.

J. Benajes; J.R. Serrano; V. Dolz; R. Novella

2009-01-01T23:59:59.000Z

143

Well injection valve with retractable choke  

SciTech Connect

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

Pringle, R.E.

1986-07-22T23:59:59.000Z

144

A WEAR MODEL FOR DIESEL ENGINE EXHAUST VALVES  

SciTech Connect

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

145

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

146

Fast valve and nozzle for gas-puff operation of dense plasma focus  

Science Journals Connector (OSTI)

A simple and reliable valve and nozzle system for a very fast injection of gas has been designed and constructed for its use in gas-puff mode of dense plasma focus experiments. It delivers a very quick rise time: 55 ? s . The pressure measured in our setup at a distance of 15 mm from the nozzle output is about 0.285 mbar with a plenum pressure of 3 bars (absolute). The time between the valve aperture and pressure front arrival is 360 ? s . This result comes up as an average of about a hundred measurements. The energy input is 95 J (270 V on a 3000 ? F capacitor bank). The typical dimensions of the valve are 52 mm in diameter and 80 mm in length. The entire volume of the valve is then very small. The relative low pressure and voltage operation are significant advantages of this development. The performance of the valve satisfactorily fulfills the objectives of gas-puff plasma focus operation.

Mara M. Milanese; Jorge O. Pouzo; Osvaldo D. Cortzar; Roberto L. Moroso

2006-01-01T23:59:59.000Z

147

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

DOE Patents (OSTI)

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

Meisner, Gregory P

2013-10-08T23:59:59.000Z

148

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

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

May 18-22, 2009 -- Washington D.C. pmp01blau.pdf More Documents & Publications Friction and Wear Reduction in Diesel Engine Valve Trains Materials for Advanced Engine Valve Train...

149

Novel design of a rotary valve using axiomatic design  

E-Print Network (OSTI)

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

Peliks, Robert Bilgor

2005-01-01T23:59:59.000Z

150

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

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

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

151

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

SciTech Connect

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

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

2010-01-01T23:59:59.000Z

152

The pipeline and valve location problem  

Science Journals Connector (OSTI)

This paper, proposes an exact algorithm for the problem of locating a pipeline between two points of a network, as well as a set of safety valves which help control the damage caused by possible spills along the pipeline. A labelling approach is developed to determine simultaneously the optimal pipeline and valve locations, with the objective of optimising an impact measure that depends on the average number of accidents and their cost. Computational experiments on grid and random instances are presented in order to evaluate the algorithm's performance and to compare its results to the solutions provided by sequential approaches. [Received 11 May 2010; Revised 10 October 2010; Accepted 21 November 2010

Gilbert Laporte; Marta M.B. Pascoal

2012-01-01T23:59:59.000Z

153

Control of Variable Geometry Turbocharged Diesel Engines for Reduced Emissions  

E-Print Network (OSTI)

in a Diesel engine equipped with a variable geometry tur- bocharger (VGT) and an external exhaust gas INJECTION EXHAUST MANIFOLD EGR VALVE EGR COOLER AIR EXHAUST Figure 1: Schematic representation of the DieselControl of Variable Geometry Turbocharged Diesel Engines for Reduced Emissions A.G. Stefanopoulouz

Stefanopoulou, Anna

154

Analyzing the impact of environmental variables on the repayment time for solar farms under feed-in tariff  

Science Journals Connector (OSTI)

Using a bootstrap analysis of solar irradiation time series, we model solar farms which sell their power output at ... one used in the province of Ontario, Canada. We show that the feed-in tariff ... remove the f...

Bin Lu; Matt Davison

2013-03-01T23:59:59.000Z

155

Modeling Cylinder Valve in Hydrogen Fuel Cell Car  

Science Journals Connector (OSTI)

We develop a fast alternative to a complex finite element analysis (FEA) model of cylinder valve in hydrogen fuel cell car based on support vector machine (SVM). The inputs of model are shape parameters of core and plunger of the valve, and the output ... Keywords: modeling, cylinder valve, SVM, uniform design

Liang Yu; Shengnian Cai; Wang Na

2011-03-01T23:59:59.000Z

156

Design for Control System of Wastegate Valve Actuator in Turbocharger  

Science Journals Connector (OSTI)

This paper has designed a set of control system of waste gate valve actuator in turbocharger, it enables the waste gate valve regulate the exhaust flow before turbo automatically according to the operating condition of engine, so it can lower the pressure ... Keywords: wastegate valve, electronic control, design, test

Liu Xinghua; Yu Lei; Liu Fushui; Wu Wenfeng; Wang Ruwei

2010-12-01T23:59:59.000Z

157

Variable geometry exhaust manifold turbocharging system for an 8-cylinder marine diesel engine  

Science Journals Connector (OSTI)

The variable geometry exhaust manifold (VGEM) turbocharging system can realize the switch between two charging modes by the switching valve, and it can give a good performance both at the high load operation and ...

Lei Shi; Shaoming Wang; Kangyao Deng; Yi Cui

2012-06-01T23:59:59.000Z

158

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

E-Print Network (OSTI)

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

Boyer, Edmond

159

Modeling the Variability of Single-Cell Lag Times for Listeria innocua Populations after Sublethal and Lethal Heat Treatments  

Science Journals Connector (OSTI)

...the shift of the distribution assumed to be...cell). After heat treatments in...resulted in a loss of viability...the preceding heat treatment. This...single-cell lag time distributions of Listeria cells exposed to heat treatments of...treatment in which no loss of viability occurred...

A. Mtris; S. M. George; B. M. Mackey; J. Baranyi

2008-09-26T23:59:59.000Z

160

Heart Valve Disease James S. Gammie, MD  

E-Print Network (OSTI)

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

Weber, David J.

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

New safety valve addresses environmental concerns  

SciTech Connect

This paper reports that Conoco Pipeline is using a unique relief valve to reduce costs while improving environmental protection at its facilities. Conoco Pipeline Co. Inc. began testing new relief valves in 1987 to present over-pressuring its pipelines while enhancing the safety, environmental integrity and profitability of its pipelines. Conoco worked jointly with Rupture Pin Technology Inc., Oklahoma City, to seek a solution to a series of safety, environmental, and operational risks in the transportation of crude oil and refined products through pipelines. Several of the identified problems were traced to a single equipment source: the reliability of rupture discs used at pipeline stations to relieve pressure by diverting flow to tanks during over-pressure conditions. Conoco's corporate safety and environmental policies requires solving problems that deal with exposure to hydrocarbon vapors, chemical spills or the atmospheric release of fugitive emissions, such as during rupture disc maintenance. The company had used rupture pin valves as vent relief devices in conjunction with development by Rick Austin of inert gas methods to protect the inner casing wall and outer carrier pipeline wall in pipeline road crossings. The design relies on rupture pin valves set at 5 psi to isolate vent openings from the atmosphere prior to purging the annular space between the pipeline and casing with inert gas to prevent corrosion. Speciality Pipeline Inspection and Engineering Inc., Houston, is licensed to distribute the equipment for the new cased-crossing procedure.

Taylor, J. (Rupture Pin Technology, Inc. Oklahoma City, OK (United States)); Austin, R. (Conoco Pipeline Co., Hennessey, OK (United States))

1992-10-01T23:59:59.000Z

162

Microfluidic Cell Electroporation Using a Mechanical Valve  

E-Print Network (OSTI)

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

Lu, Chang

163

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

164

Valve supporting arrangement of an internal combustion engine  

SciTech Connect

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

Hayashi, Y.

1986-05-27T23:59:59.000Z

165

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.

Harris, Stephen P.; Gross, Robert E.

2013-03-26T23:59:59.000Z

166

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

167

Analysis of HFIR pressurizer pump overspeed transients and relief valve performance  

SciTech Connect

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

Sozer, M.C.

1992-09-11T23:59:59.000Z

168

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

169

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

SciTech Connect

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

Sulfredge, Charles David [ORNL

2007-07-01T23:59:59.000Z

170

Curved butterfly bileaflet prosthetic cardiac valve  

DOE Patents (OSTI)

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

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

1991-06-25T23:59:59.000Z

171

Are subsurface safety valves needed in deepwater?  

SciTech Connect

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

Verret, A.; Hey, C.

1995-11-01T23:59:59.000Z

172

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

173

Quantum theory of optical temporal phase and instantaneous frequency. II. Continuous-time limit and state-variable approach to phase-locked loop design  

SciTech Connect

We consider the continuous-time version of our recently proposed quantum theory of optical temporal phase and instantaneous frequency [M. Tsang et al., Phys. Rev. A 78, 053820 (2008)]. Using a state-variable approach to estimation, we design homodyne phase-locked loops that can measure the temporal phase with quantum-limited accuracy. We show that postprocessing can further improve the estimation performance if delay is allowed in the estimation. We also investigate the fundamental uncertainties in the simultaneous estimation of harmonic-oscillator position and momentum via continuous optical phase measurements from the classical estimation theory perspective. In the case of delayed estimation, we find that the inferred uncertainty product can drop below that allowed by the Heisenberg uncertainty relation. Although this result seems counterintuitive, we argue that it does not violate any basic principle of quantum mechanics.

Tsang, Mankei; Shapiro, Jeffrey H. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Lloyd, Seth [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2009-05-15T23:59:59.000Z

174

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)

175

Novel 4-Way Refrigerant Reversing Valve for Heat Pumps  

SciTech Connect

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

Darin W. Nutter

2000-02-17T23:59:59.000Z

176

Subsurface safety valve with lock-open system  

SciTech Connect

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

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

1986-11-25T23:59:59.000Z

177

Soft robot actuators using energy-efficient valves controlled by electropermanent magnets  

E-Print Network (OSTI)

This paper presents the design, fabrication, and evaluation of a novel type of valve that uses an electropermanent magnet [1]. This valve is then used to build actuators for a soft robot. The developed EPM valves require ...

Marchese, Andrew Dominic

178

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

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

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

179

Second Peer Review for New MGI Valves for NSTX-U  

E-Print Network (OSTI)

Second Peer Review for New MGI Valves for NSTX-U (Update on Valve Tes · Characterize this valve upto 1000 Torr.L · Describe results in Peer Review (Jan, 2014

Princeton Plasma Physics Laboratory

180

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

E-Print Network (OSTI)

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

Boyer, Edmond

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

Corrosion in HVDC valve cooling systems  

SciTech Connect

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

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

1997-04-01T23:59:59.000Z

182

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

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

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

183

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

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

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

184

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

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

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

185

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

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

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

186

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

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

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

187

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

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

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

188

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

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

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

189

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

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

Science 3 Insertion of Heart Valves by Catheterization Design Team Summary: treatment (patch) results in degenerated pulmonary heart valves. Open-heart surgery is expensive,...

190

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

191

Processing of prosthetic heart valve sounds for classification. Revision 1  

SciTech Connect

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

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

1994-04-01T23:59:59.000Z

192

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

193

Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements  

SciTech Connect

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

Candy, J V; Meyer, A W

2001-03-20T23:59:59.000Z

194

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

195

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

196

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

197

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

198

Friction and Wear Reduction in Diesel Engine Valve Trains  

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

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

199

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

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

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

200

Spin-valve photodiode Ian Appelbaum,a)  

E-Print Network (OSTI)

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

Russell, Kasey

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

Thermal runaway of valve-regulated lead-acid batteries  

Science Journals Connector (OSTI)

Valve-regulated lead-acid (VRLA) batteries that have aged on a float charge at constant voltage occasionally suffer from thermal runaway. Operating conditions for a VRLA battery have been simulated by changing th...

Junmei Hu; Yonglang Guo; Xuechou Zhou

2006-10-01T23:59:59.000Z

202

Investigation of valve plate in water hydraulic axial piston motor  

Science Journals Connector (OSTI)

This paper has introduced the developments of water hydraulic axial piston equipments. According to the effects of physico-chemical properties of water on water hydraulic components, a novel valve plate for water

Song-Lin Nie Ph.D; Zhuang-Yun Li

2002-03-01T23:59:59.000Z

203

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

E-Print Network (OSTI)

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

Karp, Larry S.

204

Electric actuation of a surface controlled subsea safety valve  

E-Print Network (OSTI)

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

Bartlett, Timothy Joseph

2013-02-22T23:59:59.000Z

205

Signal processing of Shiley heart valve data for fracture detection  

SciTech Connect

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

Mullenhoff, C.

1993-04-01T23:59:59.000Z

206

Signal processing of Shiley heart valve data for fracture detection  

SciTech Connect

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

Mullenhoff, C.

1993-09-01T23:59:59.000Z

207

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

208

Valving for controlling a fluid-driven reciprocating apparatus  

DOE Patents (OSTI)

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

Whitehead, J.C.

1995-06-27T23:59:59.000Z

209

Original papers: Development of prototype automated variable rate sprayer for real-time spot-application of agrochemicals in wild blueberry fields  

Science Journals Connector (OSTI)

An automated prototype variable rate (VR) sprayer was developed for control of 8 individual nozzles on a 6.1m sprayer boom for in-season, site-specific application of agrochemicals on weeds. The sprayer boom was divided into 8 sections and mounted behind ... Keywords: Controllers, Herbicides, Precision agriculture, Sensors, Spot-application, Weeds

Qamar Uz Zaman; Travis J. Esau; Arnold W. Schumann; David C. Percival; Young Ki Chang; Scott M. Read; Aitazaz A. Farooque

2011-05-01T23:59:59.000Z

210

Externally heated valve engine -- An alternative to the Stirling engine  

SciTech Connect

A new concept of the Externally Heated Valve (EHV) engine is presented. The principle of the engine operation is described in the introduction to the paper. Heat delivered to the working medium (air) in the heater, or several heaters working commutatively, can come from a combustion chamber or other heat generator such as nuclear reactors or solar collectors. The engine construction is original entirely different from the well-known Stirling engine. New results of the EHV engine computer modeling are presented. This is connected with a new kind of the annular heater applied to the EHV engine. A whirl motion inside the heater is caused to ensure the proper condition of the heat exchanger during the whole engine cycle. Three heaters working commutatively have been considered in this model. Comparisons between the power and efficiency of the Stirling engine and EHV engine have been performed for the same engine capacity, rotational frequency, maximum and minimum temperatures of the working gas and for the same mean pressures of both the engine cycles. The power of the EHV engine is in this case over three times higher than the Stirling engine power, while the efficiency of both the engines is almost the same.

Kazimierski, Z. [Tohoku Gakuin Univ., Sendai, Miyagi (Japan). Research Div. in Mechanical Engineering; Brzeski, L. [Technical Univ. of Lodz (Poland). Dept. of Mechanical Engineering

1996-12-31T23:59:59.000Z

211

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

212

Engine control system having pressure-based timing  

DOE Patents (OSTI)

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

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

2011-10-04T23:59:59.000Z

213

ISOLOK VALVE ACCEPTANCE TESTING FOR DWPF SME SAMPLING PROCESS  

SciTech Connect

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

214

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

DOE Patents (OSTI)

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

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

2014-09-23T23:59:59.000Z

215

Classification of prosthetic heart valve sounds. A parametric approach  

SciTech Connect

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

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

1995-06-01T23:59:59.000Z

216

Measuring while drilling apparatus mud pressure signal valve  

SciTech Connect

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

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

1986-12-09T23:59:59.000Z

217

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

218

An iterative algorithm for model-based predictive control of an electro-pneumatic valve actuator  

Science Journals Connector (OSTI)

The benefits of utilizing camless valve actuations for internal combustion engines are primarily due to their ability of significantly improving engine performance. There are mainly three kinds of camless valve actuators: electro-magnetic, electro-hydraulic, ...

Guoming G. Zhu; Jia Ma; Harold Schock

2009-06-01T23:59:59.000Z

219

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

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

valve is the most common cause for aortic stenosis. Risk... without such risk factors (Peltier et al., 2003). Regardless of the etiology of the aortic valve stenosis... with an ......

220

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

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

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

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

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

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

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

222

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

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

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

223

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

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

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

224

Effect of respiration on Doppler parameters of normal tricuspid porcine bioprosthetic valves  

Science Journals Connector (OSTI)

The Doppler indexes of tricuspid porcine bioprosthetic valves were evaluated in twelve patients without clinical and two-dimensional echocardiographic evidence of valve dysfunction. Peak and mean pressure grad...

Bernard Cosyns; Guy van Camp; Alain Friart

1995-03-01T23:59:59.000Z

225

Development and introduction of wire for engine valve springs in VAZ  

Science Journals Connector (OSTI)

Valve springs (inner and outer) are critical parts of a car and therefore should meet stringent requirements with respect to their endurance and elastic properties. Results of work on introducing wire for valv...

V. G. Azizbekyan; R. M. Gaizullin; M. D. Kopyl

1996-11-01T23:59:59.000Z

226

Water Consumption from Freeze Protection Valves for Solar Water Heating Systems  

SciTech Connect

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

227

Piping retrofit reduces valve-damaging flow vibration  

SciTech Connect

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

Webb, M.; Ellenberger, P.

1995-01-01T23:59:59.000Z

228

Investigation of valve failure problems in LWR power plants  

SciTech Connect

An analysis of component failures from information in the computerized Nuclear Safety Information Center (NSIC) data bank shows that for both PWR and BWR plants the component category most responsible for approximately 19.3% of light water reactor (LWR) power plant shutdowns. This investigation by Burns and Roe, Inc. shows that the greatest cause of shutdowns in LWRs due to valve failures is leakage from valve stem packing. Both BWR plants and PWR plants have stem leakage problems (BWRs, 21% and PWRs, 34%).

None

1980-04-01T23:59:59.000Z

229

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

SciTech Connect

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

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

1998-02-01T23:59:59.000Z

230

Worcester 1 Inch Solenoid Actuated Gas Operated VPS System Ball Valve  

SciTech Connect

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

231

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

SciTech Connect

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

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

1987-01-01T23:59:59.000Z

232

Pumps, pipes and valves: The heart of a system  

SciTech Connect

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

NONE

1996-05-01T23:59:59.000Z

233

Covered Product Category: Pre-Rinse Spray Valves  

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

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

234

ON CONDITION MONITORING OF EXHAUST VALVES IN MARINE DIESEL ENGINES  

E-Print Network (OSTI)

is to seal during the compression stroke, thereby providing maximum #12; combustion pressure for maximum seat and thereby provide scavenge (from scavenge air system) of the polluted air in the cylinder and fresh air intake for the following compression and combustion. Valve burn­through, or leakage, can

Mosegaard, Klaus

235

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

SciTech Connect

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

Not Available

1983-02-01T23:59:59.000Z

236

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

E-Print Network (OSTI)

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

Haak, Hein

237

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

SciTech Connect

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

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

1991-10-08T23:59:59.000Z

238

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

SciTech Connect

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

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

2008-01-01T23:59:59.000Z

239

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

SciTech Connect

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

240

Engine control system having speed-based timing  

DOE Patents (OSTI)

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

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

2012-02-14T23:59:59.000Z

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

Engine control system having fuel-based timing  

DOE Patents (OSTI)

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

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

2012-04-03T23:59:59.000Z

242

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

SciTech Connect

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

Harris, S.; Gross, R.

2014-04-01T23:59:59.000Z

243

Monitoring variability of multivariate processes  

Science Journals Connector (OSTI)

The paper focuses on determining changes in process variability of multivariate processes. The problem is compounded by the fact that any of the elements in the variance-covariance matrix of variables could change, leading to a change in the process variability. While it may not be feasible to maintain individual control charts for each element of the variance-covariance matrix, some aggregate measure of the variability criteria could be monitored to initially determine if a change has occurred in the process variability. A couple of aggregate measures are proposed and the performance of these suggested measures is explored through a simulation procedure. Compared to the traditional method, which monitors the determinant of the variance-covariance matrix, these alternatives perform well. The performance measure used is the mean time to first detection of a change in the process variability.

Amitava Mitra; Mark Clark

2014-01-01T23:59:59.000Z

244

Removable check valve for use in a nuclear reactor  

DOE Patents (OSTI)

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

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

1988-01-01T23:59:59.000Z

245

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

SciTech Connect

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

J. Napoleon

1998-12-01T23:59:59.000Z

246

The selection and maintenance of valves for the control of fugitive emissions  

SciTech Connect

The pulp and paper industry has long needed valves that (a) have extremely low stem leakage when they are new and (b) need little or no maintenance to retain that low leakage over their service life. The EPA fugitive emission regulations provide additional impetus for the pulp and paper industry to buy such valves and for the valve and packing industry to produce such valves. Even if particular operations are not covered by the fugitive emissions regulations, it is--and always has been--in a mill's best interest to have valves whose stems don't leak and need little or no maintenance to prevent that leakage. The paper gives some recommendations on how to meet that objective: selection the right packing materials; apply the right amount of stress to the packing; install the packing correctly; and use rotary valves where practical.

Dresch, C. (NIBCO Inc., Elkhart, IN (United States))

1994-08-01T23:59:59.000Z

247

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

SciTech Connect

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

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

1999-07-01T23:59:59.000Z

248

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

SciTech Connect

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

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

1996-10-01T23:59:59.000Z

249

Failure Modes and Causes for Swing and Lift Type Check Valves  

Office of Scientific and Technical Information (OSTI)

Prior to the recent work performed by Oak Ridge National Laboratory (ORNL) relative to nuclear industry check valve performance, no information was readily available regarding the...

250

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

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

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

251

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

SciTech Connect

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

VAN KATWIJK, C.

1999-07-01T23:59:59.000Z

252

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

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

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

253

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

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

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

254

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

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

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

255

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

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

Collection: Engineering ; Materials Science ; Biology and Medicine 3 Insertion of Heart Valves by Catheterization Design Team Summary: procedure for surgeons to implant heart...

256

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

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

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

257

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

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

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

258

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

DOE Patents (OSTI)

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

Wright, K.E.

1994-08-23T23:59:59.000Z

259

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

DOE Patents (OSTI)

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

Wright, Kenneth E. (Yardley, PA)

1994-01-01T23:59:59.000Z

260

Andreas A. Malikopoulos e-mail: amaliko@umich.edu  

E-Print Network (OSTI)

, variable geometry turbocharging VGT , exhaust gas recirculation EGR , and variable valve actuation VVA, which learns the values of injection timing and variable geometry turbocharging vane position

Papalambros, Panos

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

Instantaneous Measurement of Nonlocal Variables Lev Vaidman  

E-Print Network (OSTI)

Instantaneous Measurement of Nonlocal Variables Lev Vaidman 1 School of Physics and Astronomy variables related to two or more separate sites can be measured instantaneously, except for a finite time of the measurement. It is a verification measurement: it yields reliably the eigenvalues of the nonlocal variables

Vaidman, Lev

262

Explosive transients: a time-variable sky  

Science Journals Connector (OSTI)

......Calculations of the amount of gas involved suggest around...least. The absorbing gas exists before the outburst...physics improves. What drives the explosion? Work on...objects, such as Supernova News, an early warning system...ambient medium provides a natural explanation for afterglow......

David Bersier; Mike Bode; Shiho Kobayashi; Carole Mundell; Iain Steele

2011-02-01T23:59:59.000Z

263

Flexible, reusable fiberglass insulation tailored to fit valves, heat exchangers  

SciTech Connect

About 120,000 bbl/day of crude oil are refined into gasoline at the Marathon Petroleum refinery in Robinson, IL. Built in the early part of the century, the Robinson refinery has been continually updated and modernized in response to improving technology. To control heat loss on some of the unusually shaped and previously uninsulated process equipment, Marathon engineering personnel initiated a program to systematically evaluate and insulate these pieces of equipment. Primarily, over 500 valves and heat exchanger heads were losing heat which had been estimated to cost hundreds of thousands of dollars per year. The plant performed on-site evaluations of several types of removable insulation covers. The primary differences and deciding factors were in construction detail - particularly in the fasteners. Marathon chose lace-up fastening insulation covers because plant evaluation found them to be the best. Also the manufacturer agreed to provide tailor-made covers for all of the valves and heat exchanger heads. Service from the manufacturer through an insulation contractor located in Robinson was also a plus. The local contractor, working in conjunction with the manufacturer, conducted an in-plant survey that confirmed the already mentioned heat loss cost in the $100,000s range. It was also determined that an equipment temperature somewhere between 150 and 200/sup 0/F was the lowest temperature at which to economically install insulation. Marathon has been pleased with the performance of the insulation covers which reduce heat loss and, as an incidental benefit, provide personnel safety from hot surfaces. An important benefit has been the removability and reusability of the insulation, particularly advantageous on valves and heat exchangers the require frequent access.

Gockenbach, L.G.; Singleton, D.; Toy, D.A.

1986-06-01T23:59:59.000Z

264

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

E-Print Network (OSTI)

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

Texas at Arlington, University of

265

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

E-Print Network (OSTI)

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

Luo, Xiaoyu

266

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

E-Print Network (OSTI)

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

Quake, Stephen R.

267

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

E-Print Network (OSTI)

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

Fominov, Yakov

268

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

269

Memory effect and temperature behavior in spin valves with and without antiferromagnetic subsystems  

E-Print Network (OSTI)

Memory effect and temperature behavior in spin valves with and without antiferromagnetic subsystems Temperature behavior and memory effect in standard spin valves SV and SVs with synthetic antiferromagnetic Co/Ru/Co SV-SAF subsystems have been studied. SV-SAFs show much better temperature stability. Memory effect

Xiao, John Q.

270

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

271

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

272

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

E-Print Network (OSTI)

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

Laughlin, David E.

273

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

E-Print Network (OSTI)

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

Li, Perry Y.

274

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

SciTech Connect

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

275

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

276

Coal slurry letdown valve-concept test phase. Final report  

SciTech Connect

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

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

1984-01-01T23:59:59.000Z

277

Thermodynamic Characteristic Study of a High-temperature Flow-rate Control Valve for Fuel Supply of Scramjet Engines  

Science Journals Connector (OSTI)

Thermodynamic characteristics are of great importance for the performance of a high-temperature flow-rate control valve, as high-temperature environment may bring problems, such as blocking of spool and increasing of leakage, to the valve. In this paper, a high-temperature flow-rate control valve, pilot-controlled by a pneumatic servo system is developed to control the fuel supply for scramjet engines. After introducing the construction and working principle, the thermodynamic mathematical models of the valve are built based on the heat transfer methods inside the valve. By using different boundary conditions, different methods of simulations are carried out and compared. The steady-state and transient temperature field distribution inside the valve body are predicted and temperatures at five interested points are measured. By comparing the simulation and experimental results, a reasonable 3D finite element analysis method is suggested to predict the thermodynamic characteristics of the high-temperature flow-rate control valve.

Wen ZENG; Zhizhong TONG; Songjing LI; Hongzhou LI; Liang ZHANG

2012-01-01T23:59:59.000Z

278

Design and sizing of electromagnetic linear actuators for valve applications  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

279

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

280

Failure Modes and Causes for Swing and Lift Type Check Valves  

Office of Scientific and Technical Information (OSTI)

HPCI Mainsteam RCIC Suppression Isolation Air Pool Support Figure 2. Relative Failure Rate by System and Valve Type for Significant 191-1996 Failures for the Ten Systems with...

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

HIGH-FREQUENCY MAGNETOCAPACITANCE EFFECT IN ORGANIC SPIN VALVE WITH A  

E-Print Network (OSTI)

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

Lin, Minn-Tsong

282

Classification of heart valve single leg separations from acoustic clinical measurements  

SciTech Connect

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

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

1994-05-01T23:59:59.000Z

283

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

DOE Patents (OSTI)

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

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

2014-04-01T23:59:59.000Z

284

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

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

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

285

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

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

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

286

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

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

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

287

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

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

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

288

A PDMS membrane microvalve with one-dimensional line valve seat for robust microfluidics  

Science Journals Connector (OSTI)

We have developed a monolithic polydimethylsiloxane (PDMS) membrane microvalve with an isotropically etched valve seat for robust microfluidics. In order to avoid bonding or sticking of the PDMS membrane to the valve seat during the bonding process, the valve seat was wet-etched to be a one-dimensional line instead of a plane. The simple wet-etching technique allowed for the fabrication of an anti-bonding architecture in a scalable manner, and it intrinsically prevented contact between the PDMS membrane and valve seat when no external force was applied (i.e., normally open). This approach enables the permanent device assembly so that the microfluidic chip can be operable in a wide range of fluid pressures (e.g., over 200kPa) without any leakage and sticking problems.

Chin-Sung Park; Kyu-Youn Hwang; Wonjong Jung; Kak Namkoong; Wonseok Chung; Joon-Ho Kim; Nam Huh

2014-01-01T23:59:59.000Z

289

E-Print Network 3.0 - actuated ball valve Sample Search Results  

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

Xuan-Qi Wang, Howen Mak, and Yu-Chong Tai Summary: valve design to maximize flow rates. Pump 1st Generation The solenoid actuator produced a reciprocating... : Flow Rate vs....

290

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

291

Proximity effects in superconducting triplet spin-valve F2/F1/S  

Science Journals Connector (OSTI)

Abstract We investigate the critical temperature Tc of F2/F1/S trilayers (Fi is a ferromagnetic metal and S is a singlet superconductor), where the long-range triplet superconducting component is generated at noncollinear magnetizations of the F layers. In this paper we demonstrate a possibility of the spin-valve effect mode selection (standard switching effect, the triplet spin-valve effect or reentrant T c ( ? ) dependence) by the variation of the F2/F1 interface transparency.

R.G. Deminov; L.R. Tagirov; R.R. Gaifullin; T.Yu. Karminskaya; M.Yu. Kupriyanov; Ya.V. Fominov; A.A. Golubov

2015-01-01T23:59:59.000Z

292

The Galex Ultraviolet Variability (GUVV) Catalog  

E-Print Network (OSTI)

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

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

2005-04-21T23:59:59.000Z

293

Solar Dynamics Observatory/ Extreme Ultraviolet Variability Experiment  

E-Print Network (OSTI)

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

Mojzsis, Stephen J.

294

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

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

295

Surface damage on the mating interior and exterior pistons used in a marine exhaust valve  

Science Journals Connector (OSTI)

Abstract The wear damage occurred on the two mating pistons, interior piston and exterior piston used for a marine exhaust valve. Visual and SEM observations indicate that the heavy wear marks and wear strips with flaky spalling occurred on the contact surfaces of both pistons. The primary failure mode is the adhesive wear accompanied by little fatigue wear. Metallurgical observations reveal that a white etching layer (WEL) is presented beneath the seriously worn surfaces. XRD analysis indicates that the amount of austenite on the unworn or the lightly worn surfaces of both pistons is in a high level. During operation, the metastable austenite would transform to the martensite under the friction stress, which results in a volume expansion. The clearance between mating pistons would become small to make the friction force on the contact surfaces increase. And the increased friction force induced the concentrated frictional heating. Inadequate lubrication oil cannot bring frictional energy away in time so that the located surface temperature would exceed critical temperature (Ac3). This temperature rise is high enough for austenitization and under such high temperature, the instantaneous hardness of located contact surfaces is low to lead to the occurrence of adhesion wear. Subsequent ???? transformation would occur as the bulk of the piston rapidly conducts heat away from the piston surfaces to form a WEL on the seriously worn surface. The micro-crack formation inside the WEL and subsequent propagating would lead to the occurrence of spalling.

Zhi-wei Yu; Xiao-lei Xu; Xing-jun Niu; Tao Cai

2013-01-01T23:59:59.000Z

296

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

E-Print Network (OSTI)

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

Li, Perry Y.

297

Mechanisms for left ventricular systolic dysfunction in aortic regurgitation: Importance for predicting the functional response to aortic valve replacement  

Science Journals Connector (OSTI)

To test the hypothesis that the combined use of the time-varying distance concept and conventional circumferential stress-shortening relations would elucidate differential mechanisms for left ventricular systolic dysfunction in severe, chronic aortic regurgitation and therefore predict the functional responses to aortic valve replacement, 31 control patients and 37 patients with aortic regurgitation were studied. The studies included micromanometer left ventricular pressure determinations, biplane contrast cineangiograms under control conditions and radionuclide angiograms under control conditions and during methoxamine or nitroprusside infusions with right atrial pacing. The patients with aortic regurgitation were classified into three groups: Group I had normal Emax and stress-shortening relations, Group II had abnormal Emax but normal stress-shortening relations and Group III had abnormal Emax and stress-shortening relations. The left ventricular end-diastolic and end-systolic volumes showed a progressive increase and the ejection fraction showed a progressive decrease from Group I to III; these values differed from those in the control patients (p < 0.001). In Group I, then was a decrease in left ventricular volumes (p < 0.05) but no significant change in ejection fraction (61 7% versus 63 4%) after aortic valve replacement. In contrast, in Group II, reduction in left ventricular volumes (p < 0.01) was associated with an increase in ejection fraction from 50 8% to 64 11% (p < 0.01). Finally, in Group III, reduction in left ventricular volumes (p < 0.05) was associated with a further decrement in ejection fraction from 35 13% to 30 13%. Group I patients had compensated adequately for chronic volume overload. However, Group II had left ventricular dysfunction that was associated with an increase in the left ventricular volume/mass ratio compared with that in the control patients and Group I (p < 0.05 for both), suggesting inadequate hypertrophy and assumption of spherical geometry. Finally, irreversible myocardial dysfunction had supervened in Group III. In conclusion, a combined analysis of left ventricular chamber performance using the time-varying elastance concept and myocardial performance using conventional circumferential stress-shortening relations provides complementary information that elucidates differential mechanisms for left ventricular systolic dysfunction and therefore predicts the functional response to aortic valve replacement.

Mark R. Starling; Marvin M. Kirsh; Daniel G. Montgomery; Milton D. Gross

1991-01-01T23:59:59.000Z

298

Processing of prosthetic heart valve sounds for single leg separation classification  

SciTech Connect

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

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

1995-06-01T23:59:59.000Z

299

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

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

300

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

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

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

DOE Patents (OSTI)

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

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

1997-01-01T23:59:59.000Z

302

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

303

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

304

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

SciTech Connect

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

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

1994-12-31T23:59:59.000Z

305

Nano-oxide-layer insertion and specular effects in spin valves: Experiment and theory  

Science Journals Connector (OSTI)

We report a systematic study of NOL (nano-oxide-layer) insertion and specular effects on the giant magnetoresistance (GMR) of single, synthetic, and dual spin valves, using a semiclassical Boltzmann theory. It is confirmed that the GMR ratio is enhanced by NOL insertion inside the pinned layer or after the free layer. The enhancements are primarily due to the contribution of the majority carriers. The NOL insertions inside the inactive layers of spin valves such as the seed, under, and capping layers reduce the GMR ratio. Though introducing a NOL before or after the Cu spacer would, in principle, significantly suppress the GMR ratio due to the blocking effect or the average effect of different spin channels, large positive or negative (inverse) GMR is found by assuming spin-dependent NOL specular reflections. We have also demonstrated that specular reflection, even beyond a capping layer, may result in reduction of GMR. Upon appropriate NOL insertion, the amplitude of curve of GMR versus thickness of individual layer of spin valves may be generally enhanced, but the shape may change, depending on whether the distance of the NOL to the layer is small or large (distance effect). Finally, it is found that most results obtained for the single realistic spin valves are applicable to synthetic and dual spin valves.

L. Wang; J. J. Qiu; W. J. McMahon; K. B. Li; Y. H. Wu

2004-06-03T23:59:59.000Z

306

Variable Speed of Light Research Project Dave Schumann  

E-Print Network (OSTI)

Variable Speed of Light Research Project Dave Schumann Dr. Bharath Narayanan 21 September 2003 mathematics of the Variable Speed of Light (VSL) theory. In a paper titled, "A Time Varying Speed of Light of a variable speed of light in the early stages of the universe. They propose corrections to the cosmological

Zakharov, Vladimir

307

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

E-Print Network (OSTI)

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

Gao, Song

308

Fail save shut off valve for filtering systems employing candle filters  

DOE Patents (OSTI)

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

VanOsdol, John (Fairmont, WV)

2006-01-03T23:59:59.000Z

309

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

310

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

SciTech Connect

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

Candy, J V

1999-10-31T23:59:59.000Z

311

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

SciTech Connect

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

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

2014-05-07T23:59:59.000Z

312

Assessment of Concrete Repair Techniques for Radiologically Contaminated Tank Farm Pump and Valve Pits  

SciTech Connect

As part of the scope of Project W-314, ''Tank Farm Restoration and Safe Operations,'' the condition of pump and valve pit walls and floors is being assessed, and repairs made as needed, to support upgrading the infrastructure necessary to safely transfer tank waste for treatment. Flaws in the surfaces of the pits (e.g., concrete crack/faults, protective coating deterioration) must be repaired to ensure containment integrity and to facilitate future decontamination of the pits. This engineering study presents a cost/risk/benefit evaluation of concrete and protective coating repair methods in pump and valve pits using various manual and remote tool systems.

MINTEER, D.J.

2000-09-19T23:59:59.000Z

313

Continuously proportional variable geometry turbocharger system and method of control  

SciTech Connect

This patent describes a system for performing closed loop control of a variable geometry turbocharger (VGT) utilized in an internal combustion engine. It comprises VGT actuator means for changing the geometric configuration of the VGT in response to an actuator control signal; sensor means for detecting selected engine operating parameters including a VGT actuator parameter and an engine intake manifold parameter, and generating output signals representative thereof; means for outputting a target VGT actuator parameter value and a target intake manifold parameter valve based on the values of selected sensor means output signals; means for determining whether the engine is in a steady state or a transient state of operation based on the values of selected sensor means output signals; and means for developing an actuator control signal based on one of the target parameter values as a function of the determined engine operating state.

Younessi, R.; Rini, G.T.

1992-06-23T23:59:59.000Z

314

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

E-Print Network (OSTI)

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

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

2012-01-01T23:59:59.000Z

315

Variable Frequency Drives  

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

How BPA Supports VFDs Rebates are available from your utility for Variable Frequency Drives on pumps 20hp or greater and storage fans.. Energy savings from VFDs vary and can...

316

Real-Time, On-Line Characterization of Diesel Generator Air Toxic Emissions by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry  

Science Journals Connector (OSTI)

Real-Time, On-Line Characterization of Diesel Generator Air Toxic Emissions by Resonance-Enhanced Multiphoton Ionization Time-of-Flight Mass Spectrometry ... For the same reasons, the far more abundant exhaust gases such as nitrogen, water, and carbon dioxide cannot be ionized and, therefore, do not interfere with the potential detection of low (2?100 pptv) concentrations of organic molecules. ... The sample was introduced into the ionization chamber (Figure 1) through a modified pulsed valve (General Valve Series 99) that delivers 150-?s sample pulses at atmospheric back pressure through a 0.5-mm orifice at a repetition rate of 10 Hz. ...

Lukas Oudejans; Abderrahmane Touati; Brian K. Gullett

2004-03-24T23:59:59.000Z

317

A visualization study of mixture preparation mechanisms for port fuel injected spark ignition engines  

E-Print Network (OSTI)

An experimental study was carried out that examined qualitatively the mixture preparation process in port fuel injected spark ignition engines. The primary variables in this study were intake valve lift, intake valve timing, ...

Costanzo, Vincent S. (Vincent Stanley), 1979-

2004-01-01T23:59:59.000Z

318

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

319

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

SciTech Connect

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

HICKS, D.F.

1999-08-12T23:59:59.000Z

320

An Active Motion Compensation Instrument for Beating Heart Mitral Valve Surgery  

E-Print Network (OSTI)

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

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

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

E-Print Network (OSTI)

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

Zand, Robert

322

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

E-Print Network (OSTI)

Condition monitoring of motor-operated valves in nuclear power plants Pierre Granjon Gipsa of nuclear power plants. Unfortunately, today's policies present a major drawback. Indeed, these monitoring is illustrated through experimental data. 1. Introduction Nuclear power provides about 14% of the world

Boyer, Edmond

323

The Use of Coanda Wall Attachment Fluidic Switches as Gas Chromatographic Valves  

Science Journals Connector (OSTI)

......chromatographs operating in a process control application are quite...many research- ers since the commercialization of the chromatograph in the...is particularly evident in process chromatographs. Valves which...conditions are prone to fail in a process control environment where......

Raymond Annino; Jim Leone

1982-01-01T23:59:59.000Z

324

Low energy ion beam assisted deposition of a spin valve J. J. Quan,a  

E-Print Network (OSTI)

Low energy ion beam assisted deposition of a spin valve J. J. Quan,a S. A. Wolf, and H. N. G. Wadley Department of Materials Science and Engineering, School of Engineering and Applied Science interfacial structures can be created using low energy, ion assisted vapor deposition techniques with ion

Wadley, Haydn

325

CHAPTER XV - TIME SERIES  

Science Journals Connector (OSTI)

Publisher Summary This chapter provides an overview of time series. A time series is a set of observations of a variable made at different points of time and arranged in chronological order, each observation representing the value of the variable either at a given moment or during the interval of time between this observation and the preceding one. In general, the observations forming a time-series as made at equidistant intervals of time are considered. The factors affecting time-series may be recurring or nonrecurring, or evolutionary, periodic, or random. The method of moving averages consists in determining the average value for a certain number of terms of a time series and taking this average as the trend normal value for the middle of the period covered in the calculation of the average, that is, the period extent of the moving average.

ISAAC PAENSON

1970-01-01T23:59:59.000Z

326

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

327

Application of Modelica/MWorks on modeling, simulation and optimization for electro-hydraulic servo valve system  

Science Journals Connector (OSTI)

Electro-hydraulic servo valve is a typical complicated multi-domain system constituted by mechanical electric hydraulic and magnetic components which is widely used in electro-hydraulic servo systems such as construction machinery heavy equipment weapon and so forth. The traditional method of modeling and simulation of servo valve is based on block diagram or signal flow which cannot describe the servo valve system from components level nor be used in modeling and simulation of overall servo systems. In the procedure of traditional method computational causality must be involved in modeling of servo valve which is inconvenient to execute modification on components or parameters. Modelica is an object-oriented modeling language which is suited for large complex heterogeneous and multi-domain systems. The key features of Modelica are multi-domain object-oriented and non-causal which are suitable for modeling of servo valve and make the model readable reusable and easy to modify. The simulation results show similar curves with traditional method. This new servo valve modeling and simulation method can provide the engineers a more efficient way to design and optimize a servo valve and an overall servo system.

Ming Li; Guang Meng; Jianping Jing; Jinyang Liu; Zuoyang Zhong

2012-01-01T23:59:59.000Z

328

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

SciTech Connect

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

Fang, W.; Nutter, D.W.

1999-07-01T23:59:59.000Z

329

Variable Frequency Pump Drives  

E-Print Network (OSTI)

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

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

330

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

SciTech Connect

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

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

1993-07-16T23:59:59.000Z

331

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

SciTech Connect

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

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

1993-12-01T23:59:59.000Z

332

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

SciTech Connect

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

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

2010-10-15T23:59:59.000Z

333

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

SciTech Connect

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

334

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

E-Print Network (OSTI)

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

Dekany, I; Minniti, D

2011-01-01T23:59:59.000Z

335

A study on flow characteristics and discharge coefficients of safety valve used in LNG/LNG-FPSO ships  

Science Journals Connector (OSTI)

The safety valves used in liquefied natural gas floating production storage and offloading (LNG-FPSO) ships play an important role in ... controlling the release of liquefied natural gas (LNG) from pipes in an

Jun-Ho Bae; Sung-Jin Kim; Moon-Saeng Kim

2011-09-01T23:59:59.000Z

336

Fault Current Limit (FCL) Technology (Magnetic Valve Controlled Reactor-Type Fault Current Limiter Principle and Simulation)  

Science Journals Connector (OSTI)

Summarized the FCL practical research which faces to the key technical problems, briefly introduces the study of magnetic valve controllable reactor type fault current limiter principle, and the simulation result...

Chunzhe Shi

2012-01-01T23:59:59.000Z

337

A Four-Valve Pulse Tube Cryocooler with a Cooling Power over 30 W at 80 K  

Science Journals Connector (OSTI)

A single stage four-valve pulse tube cryocooler with a large cooling power at 80 K has been built and ... investigating the influence of pulse tube size on cooling performance. Initial test demonstrated that the ...

R. Li; K. Kanao; N. Watanabe; Y. Kanazawa

1998-01-01T23:59:59.000Z

338

Left ventricular incision midway between the mitral anulus and the stumps of the papillary muscles during mitral valve excision with or without rupture or aneurysmal formation: Analysis of 10 necropsy patients  

Science Journals Connector (OSTI)

Certain clinical and morphologic observations are described in 10 patients who had mitral valve replacement (MVR) and lacerations of the left ventricular (LV) free wall midway between the anulus of the mitral valve and the stumps of the LV papillary muscles. In five patients the lacerations led to LV free wall rupture, with immediate hemopericardium in two and delayed (2 to 4 days) rupture in the other three. Of the other five patients, three developed aneurysm of the LV free wall, the mouth of which was located midway between mitral anulus and papillary muscle stumps, the sites of the lacerations observed in the other seven patients. The remaining two patients had midway lacerations which produced neither rupture nor aneurysmal formation. The midway LV lacerations are considered the result of LV incisions made at the time of mitral valve excision, generally in a setting where the left-sided cardiac chambers were only mildly dilated or normal and the tips of the blades of the scissors may have been inadequately visualized during mitral excision. This complication can be prevented by leaving the posterior mitral leaflet and its attached chordae intact or by applying exquisite care during the mitral excision procedure, or both. LV midway rupture may be the most common cause of death early after MVR and operatively induced LV lacerations may lead to LV aneurysm late postoperatively.

William C Roberts; Jeffrey M Isner; Renu Virmani

1982-01-01T23:59:59.000Z

339

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.

Not Available

2002-01-01T23:59:59.000Z

340

Variable depth core sampler  

DOE Patents (OSTI)

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

Bourgeois, Peter M. (Hamburg, NY); Reger, Robert J. (Grand Island, NY)

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.


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 depth core sampler  

DOE Patents (OSTI)

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

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

1996-02-20T23:59:59.000Z

343

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

344

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

SciTech Connect

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

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

2014-05-07T23:59:59.000Z

345

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

SciTech Connect

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

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

1991-12-31T23:59:59.000Z

346

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

SciTech Connect

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

Sine, G.C.

1980-11-01T23:59:59.000Z

347

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

SciTech Connect

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

HAMMERS, J.S.

1999-08-25T23:59:59.000Z

348

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

E-Print Network (OSTI)

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

Zand, Robert

349

Towards the understanding of cyclic variability in a spark ignited engine using multi-cycle LES  

SciTech Connect

Large-Eddy Simulation (LES) has been used to analyze the occurrence and the causes of cycle-to-cycle combustion variations in a spark ignited four-valve single cylinder engine fueled with a homogeneous propane-air mixture. The combustion modeling combines an Eulerian model derived from the RANS AKTIM model that mimics the spark ignition and the Extended Coherent Flame Model (ECFM-LES) that describes the flame propagation. The motion of piston and valves is accounted for using an Arbitrary Eulerian Lagrangian (ALE) technique with body-fitted meshes. The computation covers nine consecutive complete four-stroke cycles following an initialization cycle. The obtained LES results are compared with experimental measurements. Although the number of computed cycles is fairly low, LES is shown to be able to reproduce both quantitatively and qualitatively the cyclic variability observed experimentally. The investigation of the possible causes of variability illustrates the unprecedented possibility LES offers for understanding cycle-to-cycle variations. (author)

Vermorel, O.; Richard, S.; Colin, O.; Angelberger, C.; Benkenida, A. [IFP, 1 and 4 Avenue de Bois-Preau, 92852 Rueil-Malmaison Cedex (France); Veynante, D. [EM2C, CNRS and Ecole Centrale Paris, Grande Voie des Vignes, 92295 Chatenay-Malabry (France)

2009-08-15T23:59:59.000Z

350

Estimating climatological variability of solar energy production  

Science Journals Connector (OSTI)

Abstract A method is presented for estimating the climatological variability of yearly and monthly photovoltaic power production per 1kWp of installed power. This quantity is computed for a specified portfolio of sources on the basis of historical data. Its climatological variability is derived from a simulation of 33years of power production with hourly time step. Underlying meteorological variables are taken from the MERRA reanalysis for the years 19792011. Since the MERRA reanalysis is not a traditional data source for photovoltaic power modelling, various comparisons to available and more frequently used data sources are included. The method of estimation has the advantage of wide applicability due to the global coverage of the meteorological data.

Pavel Juru; Krytof Eben; Jaroslav Resler; Pavel Kr?; Ivan Kasanick; Emil Pelikn; Marek Brabec; Ji? Hoek

2013-01-01T23:59:59.000Z

351

Measuring spatial variability in soil characteristics  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

352

PHP: Constructs and Variables Introduction  

E-Print Network (OSTI)

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

Vander Zanden, Brad

353

The dynamics of variable-density turbulence  

SciTech Connect

The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field, is in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 128{sup 3} grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations. In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For the case of buoyancy-generated turbulence, variable-density departures from the Boussinesq approximation are studied. The results of the buoyancy-generated turbulence are compared with variable-density model predictions. Both a one-point (engineering) model and a two-point (spectral) model are tested against the numerical data. Some deficiencies in these variable-density models are discussed and modifications are suggested.

Sandoval, D.L.

1995-11-01T23:59:59.000Z

354

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

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

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

355

Light absorption cell combining variable path and length pump  

DOE Patents (OSTI)

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

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

1993-01-01T23:59:59.000Z

356

Light absorption cell combining variable path and length pump  

DOE Patents (OSTI)

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

Prather, W.S.

1993-12-07T23:59:59.000Z

357

A Search for Chaotic Behavior in Stratospheric Variability: Comparison between the Northern and Southern Hemispheres  

Science Journals Connector (OSTI)

Southern Hemisphere (SH) stratospheric variability is investigated with respect to chaotic behavior using time series from three different variables extracted from four different reanalysis products. The results are compared with the same analysis ...

Gualtiero Badin; Daniela I.V. Domeisen

2014-12-01T23:59:59.000Z

358

Stochastic Estimation of Multi-Variable Human Ankle Mechanical Impedance  

E-Print Network (OSTI)

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

Rastgaar Aagaah, Mohammad

359

Intrinsic Time Quantum Geometrodynamics  

E-Print Network (OSTI)

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

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

2015-01-26T23:59:59.000Z

360

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

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

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

362

Analysis of two basic variables of timeout  

E-Print Network (OSTI)

in reducing the rate of a designated behavior. Timeout from positive reinforcement is a behavior modification technique in which positive reinforcers are withdrawn for a period of time following a target response (White, Nielsen, and Johnson, 1972... variable (White, Nielsen, and Johnson, 1972) did not reach a decisive conclusion because of a sequencing problem in the method. The effects of three different timeout durations were investigated in a group of 20 retarded, institution- alized subjects...

Zella, William Francis

2012-06-07T23:59:59.000Z

363

Distributed digital real-time control system for TCV tokamak  

Science Journals Connector (OSTI)

Abstract A new digital feedback control system (named the SCD Systme de Contrle Distribu) has been developed, integrated and used successfully to control TCV (Tokamak Configuration Variable) plasmas. The system is designed to be modular, distributed, and scalable, accommodating hundreds of diagnostic inputs and actuator outputs. With many more inputs and outputs available than previously possible, it offers the possibility to design advanced control algorithms with better knowledge of the plasma state and to coherently control all TCV actuators, including poloidal field (PF) coils, gas valves, the gyrotron powers and launcher angles of the electron cyclotron heating and current drive system (ECRH/ECCD) together with diagnostic triggering signals. The system consists of multiple nodes; each is a customised Linux desktop or embedded PC which may have local ADC and DAC cards. Each node is also connected to a memory network (reflective memory) providing a reliable, deterministic method of sharing memory between all nodes. Control algorithms are programmed as block diagrams in Matlab-Simulink providing a powerful environment for modelling and control design. The C code is generated automatically from the Simulink block diagram and compiled, with the Simulink Embedded Coder (SEC, formerly Real-Time Workshop Embedded Coder), into a Linux shared library (.so file) and distributed to target nodes in the discharge preparation phase. During the TCV discharge, an application on each node is executed that dynamically loads the shared library at runtime. In order to obtain reliable and reproducible real time execution of the algorithm, all interrupts to the CPU on each node are suspended just before firing the shot and re-enabled afterwards. Since installation, the new digital control system has been used for a multitude of plasma control applications, ranging from basic experiments of coil current and density control to advanced experiments of MHD (magnetohydrodynamics) and plasma profile control, as well as real-time plasma transport simulations. Recently, a real-time version of a plasma equilibrium reconstruction code was developed and implemented, providing the future possibility to control the plasma shape and profiles directly during the discharge evolution. This paper presents the architecture of the new control system, its integration into the TCV plant and a sample of control applications used for TCV plasma discharges.

H.B. Le; F. Felici; J.I. Paley; B.P. Duval; J.-M. Moret; S. Coda; O. Sauter; D. Fasel; P. Marmillod

2014-01-01T23:59:59.000Z

364

VARIABLE FIRING RATE OIL BURNER USING PULSE FUEL FLOW CONTROL.  

SciTech Connect

The residential oil burner market is currently dominated by the pressure-atomized retention head burner, which has an excellent reputation for reliability and efficiency. In this burner, oil is delivered to a fuel nozzle at pressures from 100 to 150 psi. In addition, to atomizing the fuel, the small, carefully controlled size of the nozzle exit orifice serves to control the burner firing rate. Burners of this type are currently available at firing rates of more than 0.5 gallons-per-hour (70,000 Btu/hr). Nozzles have been made for lower firing rates, but experience has shown that such nozzles suffer rapid fouling of the necessarily small passages, leading to bad spray patterns and poor combustion performance. Also, traditionally burners and the nozzles are oversized to exceed the maximum demand. Typically, this is figured as follows. The heating load of the house on the coldest day for the location is considered to define the maximum heat load. The contractor or installer adds to this to provide a safety margin and for future expansion of the house. If the unit is a boiler that provides domestic hot water through the use of a tankless heating coil, the burner capacity is further increased. On the contrary, for a majority of the time, the heating system is satisfying a much smaller load, as only rarely do all these demands add up. Consequently, the average output of the heating system has to be much less than the design capacity and this is accomplished by start and stop cycling operation of the system so that the time-averaged output equals the demand. However, this has been demonstrated to lead to overall efficiencies lower than the steady-state efficiency. Therefore, the two main reasons for the current practice of using oil burners much larger than necessary for space heating are the unavailability of reliable low firing rate oil burners and the desire to assure adequate input rate for short duration, high draw domestic hot water loads. One approach to solve this problem is to develop a burner, which can operate at two firing rates, with the lower rate being significantly lower than 0.5 gallons per hour. This paper describes the initial results of adopting this approach through a pulsed flow nozzle. It has been shown that the concept of flow modulation with a small solenoid valve is feasible. Especially in the second configuration tested, where the Lee valve was integrated with the nozzle, reasonable modulation in flow of the order of 1.7 could be achieved. For this first prototype, the combustion performance is still not quite satisfactory. Improvements in operation, for example by providing a sharp and positive shut-off so that there is no flow under low pressures with consequent poor atomization could lead to better combustion performance. This could be achieved by using nozzles that have shut off or check valves for example. It is recommended that more work in cooperation with the valve manufacturer could produce a technically viable system. Marketability is of course a far more complex problem to be addressed once a technically viable product is available.

KRISHNA,C.R.; BUTCHER,T.A.; KAMATH,B.R.

2004-10-01T23:59:59.000Z

365

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

E-Print Network (OSTI)

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

Gusev, Guennady

366

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

E-Print Network (OSTI)

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

Presswood, James Columbus

1977-01-01T23:59:59.000Z

367

Helium ion beam milling to create a nano-structured domain wall magnetoresistance spin valve  

Science Journals Connector (OSTI)

We have fabricated and measured single domain wall magnetoresistance devices with sub-20nm gap widths using a novel combination of electron beam lithography and helium ion beam milling. The measurement wires and external profile of the spin valve are fabricated by electron beam lithography and lift-off. The critical bridge structure is created using helium ion beam milling, enabling the formation of a thinner gap (and so a narrower domain wall) than that which is possible with electron beam techniques alone. Four-point probe resistance measurements and scanning electron microscopy are used to characterize the milled structures and optimize the He ion dose. Successful operation of the device as a spin valve is demonstrated, with a 0.2% resistance change as the external magnetic field is cycled. The helium ion beam milling efficiency as extracted from electrical resistance measurements is 0.044atoms/ion, about half the theoretical value. The gap in the device is limited to a maximum of 20nm with this technique due to sub-surface swelling caused by injected ions which can induce catastrophic failure in the device. The fine patterning capabilities of the helium ion microscope milling technique indicate that sub-5nm constriction widths could be possible.

Yudong Wang; S A Boden; D M Bagnall; H N Rutt; C H de Groot

2012-01-01T23:59:59.000Z

368

Parental Time, Behaviors and Childhood Obesity  

E-Print Network (OSTI)

towards child health are modeled and analyzed using instrument variable (IV) methods. Results indicate that the effect of mother's time allocation reduces child weight status. Her decision to allocate time to the child is affected by unseen factors. Father...

Kuteesa, Annette

2012-02-14T23:59:59.000Z

369

Selection automatique de variables pertinentes  

E-Print Network (OSTI)

S´election automatique de variables pertinentes Vers la d´ecouverte de nouvelles modalit´es sensori-motrices corr´elations entre ses variables sensori-motrices afin d'apprendre `a r´esoudre sa t^ache d

Boyer, Edmond

370

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

371

Teleportation-Based Continuous Variable Quantum Cryptography  

E-Print Network (OSTI)

We show a continuous variable (CV) quantum key distribution (QKD) scheme based on the CV quantum teleportation of coherent states that yields a raw secret key made up of discrete variables for both Alice and Bob. This protocol preserves the efficient detection schemes of current CV technology (no single-photon detection techniques) and, at the same time, has efficient error correction and privacy amplification schemes due to its binary discrete key. In particular, it is secure for any value of the transmission efficiency of the optical line used by Alice to share entangled two-mode squeezed states with Bob (no 3 dB or 50% loss limitation characteristic of beam splitting attacks). The present CVQKD protocol works deterministically (no postselection needed) with efficient direct reconciliation techniques (no reverse reconciliation) in order to generate a secure key, even at the surprisingly 100% loss case.

F. S. Luiz; Gustavo Rigolin

2014-08-21T23:59:59.000Z

372

Long-term climate variability and abrupt climate change Instructor: Dr. Igor Kamenkovich, associate professor  

E-Print Network (OSTI)

Long-term climate variability and abrupt climate change Instructor: Dr. Igor Kamenkovich, associate students to learn about existing theories of abrupt climate changes and climate variability on time scales of long-term climate variability and abrupt climate change. This course compliments current MPO courses

Miami, University of

373

Energy-Saving Adaptive Robust Motion Control of Single-Rod Hydraulic Cylinders with Programmable Valves 1  

E-Print Network (OSTI)

- ety's need for energy conservation while without sacrificing the achievable motion control accuracy that the meter-in and meter-out orifices are mechanically linked together in a typical directional control valve of activities in industry on breaking the mechanical linkage between the meter-in and meter-out orifices

Yao, Bin

374

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

E-Print Network (OSTI)

Energy-Saving Control of Single-Rod Hydraulic Cylinders with Programmable Valves and Improved. ABSTRACT This paper studies the energy-saving adaptive robust precision motion control of a single and individual cylinder chamber pressure control for better energy saving. With a typical four-way directional

Yao, Bin

375

High-speed and bi-stable electrolysis-bubble actuated planar micro gate valves are demonstrated in this paper.  

E-Print Network (OSTI)

SUMMARY High-speed and bi-stable electrolysis-bubble actuated planar micro gate valves are demonstrated in this paper. The speed of previous low power planar microvalves was limited by the bubble collapse process. In addition bi-stability was unreliable. In this work, surface tension is used

Liepmann, Dorian

376

On-engine evaluation of emission characteristics of a variable geometry lean-premixed combustor  

SciTech Connect

The design and on-engine testing of a lean-premixed, low-NO{sub x} combustor for a simple-cycle, single-shaft, 250-kW gas turbine engine of a pressure ratio of eight are described. A variable-geometry system composed of butterfly air valves was used to control the combustor air split between combustion and dilution. Fuel was staged to a direct-injection pilot burner, and a lean-premixed main burner was fitted to the combustor liner. The NO{sub x} emissions with natural gas fueling were found to be less than 20 ppm (at 5% O{sub 2}) at and near full-load conditions with combustion efficiencies greater than 99.8%. Emissions data from early high-pressure rig tests of the combustor hardware are also presented.

Yamada, H.; Shimodaira, K.; Hayashi, S. [National Aerospace Lab., Tokyo (Japan). Thermofluid Dynamics Div.

1997-01-01T23:59:59.000Z

377

ENSEMBLE VARIABILITY OF NEAR-INFRARED-SELECTED ACTIVE GALACTIC NUCLEI  

SciTech Connect

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

378

Center-pivot automatization for agrochemical use  

Science Journals Connector (OSTI)

This paper presents an agrochemical application system that could be incorporated into existing irrigating center-pivots. The system consisted of a hydraulic circuit with emitters, where the dose was individually controlled with variable valve timing. ... Keywords: Agriculture, Center-pivot, Control applications, Variable valve timing control

J. Palacn; J. A. Salse; X. Clua; J. Arn; R. Blanco; C. Zanuy

2005-12-01T23:59:59.000Z

379

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

380

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.

Gross, Robert E. [Savannah River Site (SRS), Aiken, SC (United States); Bukowski, Julia V. [Villanova University, Villanova, PA (United States); Goble, William M. [exida, Sellersville, PA (United States)

2013-04-16T23:59:59.000Z

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

Electron-electron interaction, weak localization and spin valve effect in vertical-transport graphene devices  

SciTech Connect

We fabricated a vertical structure device, in which graphene is sandwiched between two asymmetric ferromagnetic electrodes. The measurements of electron and spin transport were performed across the combined channels containing the vertical and horizontal components. The presence of electron-electron interaction (EEI) was found not only at low temperatures but also at moderate temperatures up to ?120?K, and EEI dominates over weak localization (WL) with and without applying magnetic fields perpendicular to the sample plane. Moreover, spin valve effect was observed when magnetic filed is swept at the direction parallel to the sample surface. We attribute the EEI and WL surviving at a relatively high temperature to the effective suppress of phonon scattering in the vertical device structure. The findings open a way for studying quantum correlation at relatively high temperature.

Long, Mingsheng; Gong, Youpin; Wei, Xiangfei; Zhu, Chao; Xu, Jianbao; Liu, Ping; Guo, Yufen; Li, Weiwei; Liu, Liwei, E-mail: lwliu2007@sinano.ac.cn [Key Laboratory of Nanodevices and Applications-CAS and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Liu, Guangtong [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2014-04-14T23:59:59.000Z

382

Spin-dependent thermal and electrical transport in a spin-valve system  

SciTech Connect

Within the framework of Bu{close_quotes}ttiker{close_quote}s gauge invariant and charge conservation dc transport theory, the spin-dependent thermal and electrical transport in a ferromagnet-insulator-ferromagnet tunnel junction is investigated at finite bias voltage and finite temperature. It is observed that the relative orientations of magnetizations in the two ferromagnetic (FM) electrodes as well as temperature have remarkable effects on the differential conductance, thermopower, Peltier effect, and thermal conductivity. At low temperature the quantum resonant tunneling is predominant, leading to the deviation of classical transport theory, while the transport of electrons are crucially governed by thermal processes at high temperature. The so-called spin-valve phenomenon is clearly uncovered for both the differential conductance and the thermal conductivity at low temperature. The Wiedemann-Franz law is examined, and the inelastic tunneling spectroscopy is also discussed. Our findings are expected to be measured in the near future.

Wang, Zheng-Chuan; Su, Gang; Gao, Song

2001-06-01T23:59:59.000Z

383

Thermal engineering of non-local resistance in lateral spin valves  

SciTech Connect

We study the non-local spin transport in Permalloy/Cu lateral spin valves (LSVs) fabricated on thermally oxidized Si and MgO substrates. While these LSVs show the same magnitude of spin signals, significant substrate dependence of the baseline resistance was observed. The baseline resistance shows much weaker dependence on the inter-electrode distance than that of the spin transport observed in the Cu wires. A simple analysis of voltage-current characteristics in the baseline resistance indicates the observed result can be explained by a combination of the Peltier and Seebeck effects at the injector and detector junctions, suggesting the usage of high thermal conductivity substrate (or under-layer) is effective to reduce the baseline resistance.

Kasai, S., E-mail: KASAI.Shinya@nims.go.jp; Takahashi, Y. K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Hirayama, S.; Mitani, S.; Hono, K. [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-0006 (Japan); Adachi, H.; Ieda, J.; Maekawa, S. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); CREST, Japan Science and Technology Agency, Sanbancho, Tokyo 102-0075 (Japan)

2014-04-21T23:59:59.000Z

384

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Paulauskas, Felix L. (Oak Ridge, TN); Fathi, Zakaryae (Cary, NC); Wei, Jianghua (Raleigh, NC)

1998-01-01T23:59:59.000Z

385

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-09-08T23:59:59.000Z

386

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-08-25T23:59:59.000Z

387

The dynamics of variable-density turbulence  

SciTech Connect

The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field is, in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 128{sup 3} grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations (such that the Boussinesq approximation is not valid). In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For this case, the pdf of the density becomes asymmetric about its mean value during the early stages of its evolution. It is argued that these asymmetries in the pdf of the density field are due to different entrainment rates, into the mixing region, that favor the high speed fluid.

Sandoval, D.L.

1995-11-01T23:59:59.000Z

388

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

389

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.

Not Available

1994-08-01T23:59:59.000Z

390

Reading with fixed and variable character pitch  

Science Journals Connector (OSTI)

We compared the effects of fixed and variable (proportional) spacing on reading speeds and found variable pitch to yield better performance at medium and large character sizes and...

Arditi, Aries; Knoblauch, Kenneth; Grunwald, Ilana

1990-01-01T23:59:59.000Z

391

Dynamical dark energy or variable cosmological parameters?  

E-Print Network (OSTI)

One of the main aims in the next generation of precision cosmology experiments will be an accurate determination of the equation of state (EOS) for the dark energy (DE). If the latter is dynamical, the resulting barotropic index \\omega should exhibit a non-trivial evolution with the redshift. Usually this is interpreted as a sign that the mechanism responsible for the DE is related to some dynamical scalar field, and in some cases this field may behave non-canonically (phantom field). Present observations seem to favor an evolving DE with a potential phantom phase near our time. In the literature there is a plethora of dynamical models trying to describe this behavior. Here we show that the simplest option, namely a model with a variable cosmological term, \\Lambda=\\Lambda(t), leads in general to a non-trivial effective EOS, with index \\omega_e, which may naturally account for these data features. We prove that in this case there is always a ``crossing'' of the \\omega_e=-1 barrier near our time. We also show how this effect is modulated (or even completely controled) by a variable Newton's constant G=G(t).

Joan Sola; Hrvoje Stefancic

2005-12-21T23:59:59.000Z

392

Oxygen isotope analysis of multiple, single ostracod valves as a proxy for combined variability in seasonal temperature and lake water oxygen isotopes  

Science Journals Connector (OSTI)

Paleoclimate studies in lakes typically use oxygen isotopic ratios in samples that consist of multiple ostracod specimens, to obtain an average ?18O value that reflects the mean temperature and ?18O of lake water...

Yama Dixit; David A. Hodell; Rajiv Sinha; Cameron A. Petrie

2014-10-01T23:59:59.000Z

393

Temperature dependent nucleation, propagation, and annihilation of domain walls in all-perpendicular spin-valve nanopillars  

SciTech Connect

We present a study of the temperature dependence of the switching fields in Co/Ni-based perpendicularly magnetized spin-valves. While magnetization reversal of all-perpendicular Co/Ni spin valves at ambient temperatures is typically marked by a single sharp step change in resistance, low temperature measurements can reveal a series of resistance steps, consistent with non-uniform magnetization configurations. We propose a model that consists of domain nucleation, propagation, and annihilation to explain the temperature dependence of the switching fields. Interestingly, low temperature (<30?K) step changes in resistance that we associate with domain nucleation have a bimodal switching field and resistance step distribution, attributable to two competing nucleation pathways.

Gopman, D. B., E-mail: daniel.gopman@physics.nyu.edu; Kent, A. D. [Department of Physics, New York University, New York, New York 10003 (United States); Bedau, D. [Department of Physics, New York University, New York, New York 10003 (United States); HGST San Jose Research Center, San Jose, California 95135 (United States); Mangin, S. [Institut Jean Lamour, UMR CNRS 7198 Universit de Lorraine, Nancy, France 54506 (France); Fullerton, E. E. [CMRR, University of California at San Diego, La Jolla, California 92093 (United States); Katine, J. A. [HGST San Jose Research Center, San Jose, California 95135 (United States)

2014-03-21T23:59:59.000Z

394

Operating Reserves and Variable Generation  

SciTech Connect

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

395

Cosmological models with variable constants  

E-Print Network (OSTI)

The behavior of the constants, G,c,h,a,e,m and Lambda, considering them as variable, in the framework of a flat cosmological model with FRW symmetries described by a bulk viscous fluid and considering mechanisms of adiabatic matter creation are investigated. Within two models; one with radiation predominance and another of matter predominance, this behavior are studied.

J. A. Belinchon

1999-07-01T23:59:59.000Z

396

Variable trim compressor a new approach to variable compressor geometry  

Science Journals Connector (OSTI)

ABSTRACT Variable compressor geometry can be employed irrespective of the combustion process selected. It provides the capability of improving response behavior, reducing fuel consumption or cutting exhaust emissions from exhaust-gas turbocharged engines. Previous concepts on variable compressor geometries have been based on using inlet guide vanes to impart a swirl motion to the air that is fed to the compressor with the ultimate aim of enhancing the angle at which the flow of air enters the blade channel. This paper shows an inlet guide configuration that is based on a different operating principle. The inlet guide assembly shown here is designed in a way that minimizes any pressure losses even at high flow rates. Numerical studies were carried out using CFD to test the system's sensitivity. Based on these studies, a rigid conical element was then produced and the potential for increasing efficiency (up to 7% points) and shifting the surge line (up to 33%) verified on a turbocharger test bench. Finally, a design configuration is presented for a variable system.

P. Grigoriadis; S. Mller; A. Benz; M. Sens

2012-01-01T23:59:59.000Z

397

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

SciTech Connect

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

398

Energy saving dispatch with complex constraints: Prohibited zones, valve point effect and carbon tax  

Science Journals Connector (OSTI)

Abstract This paper presents an energy saving dispatch (ESD) strategy, based upon the optimal power flow (OPF) model, considering complex constraints, such as prohibited operating zones, the valve point effect of generation units and the carbon tax of a power grid. With these constraints, the OPF problem becomes more difficult to resolve, and it needs to be dealt with by a more accurate and reliable optimization algorithm. In this paper, an improved group search optimizer (GSO), namely the group search optimizer with intraspecific competition and lvy walk (GSOICLW), is adopted to tackle this problem. It is more biologically realistic than GSO, in which intraspecific competition (IC) and lvy walk (LW) are incorporated in the original GSO. IC and LW of GSOICLW are capable of achieving superior balance between global and local searching, i.e., GSOICLW maintains GSOs global searching ability to avoid entrapping in local optima while improves local searching near the global optima. The standard IEEE 30-bus power system is employed to carry out the simulation study to test GSOICLW, which is subsequently compared with other evolutionary algorithms (EAs). Simulation results show that GSOICLW outperforms other \\{EAs\\} used in this research and also provides accurate and reliable optimization results in dealing with the OPF problem for ESD.

Y.Z. Li; M.S. Li; Q.H. Wu

2014-01-01T23:59:59.000Z

399

Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner  

Science Journals Connector (OSTI)

An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is \\{HFC134a\\} and the maximum cooling capacity of experiment apparatus is 32.7kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio.

Soo-Yong Cho; Chong-Hyun Cho; Chaesil Kim

2008-01-01T23:59:59.000Z

400

Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner  

SciTech Connect

An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

Cho, Soo-Yong [Department of Mechanical and Aerospace Engineering (ReCAPT), Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Cho, Chong-Hyun [School of Mechanical and Aerospace Engineering, Gyeongsang National University, 900 Gajoa-dong, Jinju 660-701 (Korea); Kim, Chaesil [Department of Mechanical Engineering, Changwon National University, 9 Sarim-dong, Changwon 641-773 (Korea)

2008-09-15T23:59:59.000Z

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

Sub-daily Statistical Downscaling of Meteorological Variables Using Neural Networks  

SciTech Connect

A new open source neural network temporal downscaling model is described and tested using CRU-NCEP reanal ysis and CCSM3 climate model output. We downscaled multiple meteorological variables in tandem from monthly to sub-daily time steps while also retaining consistent correlations between variables. We found that our feed forward, error backpropagation approach produced synthetic 6 hourly meteorology with biases no greater than 0.6% across all variables and variance that was accurate within 1% for all variables except atmospheric pressure, wind speed, and precipitation. Correlations between downscaled output and the expected (original) monthly means exceeded 0.99 for all variables, which indicates that this approach would work well for generating atmospheric forcing data consistent with mass and energy conserved GCM output. Our neural network approach performed well for variables that had correlations to other variables of about 0.3 and better and its skill was increased by downscaling multiple correlated variables together. Poor replication of precipitation intensity however required further post-processing in order to obtain the expected probability distribution. The concurrence of precipitation events with expected changes in sub ordinate variables (e.g., less incident shortwave radiation during precipitation events) were nearly as consistent in the downscaled data as in the training data with probabilities that differed by no more than 6%. Our downscaling approach requires training data at the target time step and relies on a weak assumption that climate variability in the extrapolated data is similar to variability in the training data.

Kumar, Jitendra [ORNL] [ORNL; Brooks, Bjrn-Gustaf J. [University of Illinois, Urbana-Champaign] [University of Illinois, Urbana-Champaign; Thornton, Peter E [ORNL] [ORNL; Dietze, Michael [University of Illinois, Urbana-Champaign] [University of Illinois, Urbana-Champaign

2012-01-01T23:59:59.000Z

402

Characteristics of Arctic Sea-Ice Thickness Variability in GCMs  

Science Journals Connector (OSTI)

Skillful Arctic sea ice forecasts may be possible for lead times of months or even years owing to the persistence of thickness anomalies. In this study sea ice thickness variability is characterized in fully coupled GCMs and sea iceocean-only ...

Edward Blanchard-Wrigglesworth; Cecilia M. Bitz

2014-11-01T23:59:59.000Z

403

Fast Bayesian Variable Selection Algorithms for High Dimensional Genomics Data  

E-Print Network (OSTI)

Anderson Cancer Center, USA Abstract Large-scale molecular genomics assays such as gene and micro of many diseases, especially cancer. However, the solution to such a problem requires exploring a large predict survival times of patients with brain cancer. Our method finds small sets of variables

Ordonez, Carlos

404

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

405

Variable frequency microwave heating apparatus  

DOE Patents (OSTI)

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN); Johnson, Arvid C. (Lake in the Hills, IL); Thigpen, Larry T. (Angier, NC)

1999-01-01T23:59:59.000Z

406

Chapter Seven - Variable speed drives  

Science Journals Connector (OSTI)

Publisher Summary The electromechanical controllers are a kind of variable speed drives (VSDs) that are obsolete but are still in use because when a motor and a drive is combined, they become a power drive system (PDS). There are two ways of varying the speed of an induction motor, either by varying the motor slip or by varying the supply frequency. The preferred practice for electrical speed variation is to change the supply frequency with a variable frequency drive (VFD). Many other designs also have been developed. However, except the specialized applications, few are still in operation. A number of motor and drive manufacturers are now producing the integrated motor/VFD units. These units consist of a motor and a specially designed VFD, produced as a single package, with the VFD unit mounted variously on the top, side, or end of the motor.

Europump; Hydraulic Institute

2005-01-01T23:59:59.000Z

407

Review of Probability Random Variable  

E-Print Network (OSTI)

at close 4) Height of wheel going over a rocky road #12;3 Random Variable Non-examples 1) `Heads' or `Tails' on coin 2) Red or Black ball from urn But we can make these into RV's Basic Idea ­ don't know · Temperature · Wheel height #12;5 Given Continuous RV X... What is the probability that X = x0 ? Oddity : P

Fowler, Mark

408

On adaptive grid computations of variable stars  

SciTech Connect

We show that the use of an implicit adaptive-grid technique is an efficient and up-to-date approach for the calculations of radial oscillations in variable stars. We chose as an illustrative example the radiative envelope of an RR Lyrae variable. For the hydrostatic initial model we compare the Lagrangean ratioed zoning with an adaptive-grid rezoning. We show that the adaptive-grid yields an optimal distribution of the mesh points in the sense that the relevant physical features, the H{minus} and He 1{minus}, He 2{minus} ionization zones, are well resolved. For the hydrodynamical evolution we present the full-amplitude model for both the Lagrangean and adaptive-grid computations. We perform a detailed comparison and show that the adaptive-grid method yields limit cycle solutions that are substantially improved over the Lagrangean grid model. This is due to the fact that the Lagrangean mesh sweeps through the ionization zones twice during one oscillation period, whereas the adaptive-mesh resolves them and tracks them continuously. The results are, in particular, smooth radial velocity and light curves. Beyond a physically better defined solution we also observe larger time steps for the convergence towards the limit cycle and for the evolution during one period. 12 refs., 13 figs., 5 tabs.

Cox, A.N.; Deupree, R.G.; Gehmeyr, M.

1991-01-01T23:59:59.000Z

409

Improvements of the Variable Thermal Resistance  

E-Print Network (OSTI)

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

V. Szekely; S. Torok; E. Kollar

2008-01-07T23:59:59.000Z

410

Dark matter interacts with variable vacuum energy  

E-Print Network (OSTI)

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) scenario with two interacting components, dark matter and variable vacuum energy (VVE) densities, plus two decoupled components, one is a baryon term while the other behaves as a radiation component. We consider a linear interaction in the derivative dark component density. We apply the $\\chi^2$ method to the observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era for the model. It turns out that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)survey, the future constraints achievable by Euclid and CMBPol experiments, reported for the behavior of the dark energy at early times, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at $2\\sigma$ level in the big-bang nucleosynthesis epoch. We a...

G, Ivn E Snchez

2014-01-01T23:59:59.000Z

411

The fainter the better: cataclysmic variable stars from the SDSS  

E-Print Network (OSTI)

The Sloan Digital Sky Survey has identified a total of 212 cataclysmic variables, most of which are fainter than 18th magnitude. This is the deepest and most populous homogeneous sample of cataclysmic variables to date, and we are undertaking a project to characterise this population. We have found that the SDSS sample is dominated by a great ``silent majority'' of old and faint CVs. We detect, for the first time, a population spike at the minimum period of 80 minutes which has been predicted by theoretical studies for over a decade.

John Southworth; B T Gaensicke; T R Marsh

2008-10-27T23:59:59.000Z

412

2013 INTERNSHIP REPORT RICE MBA FULL TIME  

E-Print Network (OSTI)

Mackey Finance & Operations Intern Amazon Samarth Jain Sr.Product Manager Intern American Airlines Intern,Valves & Measurement Wolfgang von der Rosen Intern,Valves & Measurement CBM Enterprise Solutions Haldar Summer Associate Enterprise Products, LP Alex Weaver Commercial Analyst Ernst & Young Emily

Richards-Kortum, Rebecca

413

Variable pressure operation: An assessment  

SciTech Connect

This report summarizes the benefits, drawbacks, and technical issues of variable pressure operation (VPO) retrofit. Under VPO, turbine throttle pressure is reduced at low loads. This operating mode offers several significant advantages for units that cycle or operate at low loads for extended periods. Information used in the report was assembled from published sources, from major equipment manufacturers, and from utilities operating units under VPO in the US, Europe and Japan. The report also contains statistics of VPO use in this country and abroad. Design features of new units using VPO in Europe and Japan are presented to identify potential directions for future US designs incorporating VPO.

Kimel, E.; Kemeny, P.; Bierman, E.; Lagomarsino, J.; Clarke, D. (Burns and Roe, Inc., Oradell, NJ (USA))

1990-03-01T23:59:59.000Z

414

A group bridge approach for variable selection  

Science Journals Connector (OSTI)

......group bridge approach for variable...Actuarial Science, University...Department of Management Science, University...group bridge approach that is capable...group bridge approach for variable...Actuarial Science, University...Department of Management Science......

Jian Huang; Shuange Ma; Huiliang Xie; Cun-Hui Zhang

2009-06-01T23:59:59.000Z

415

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

SciTech Connect

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

416

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)

417

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

418

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

419

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.

420

Variable White Dwarf Data Tables  

SciTech Connect

Below, I give a brief explanation of the information in these tables. In all cases, I list the WD {number_sign}, either from the catalog of McCook {ampersand} Sion (1987) or determined by me from the epoch 1950 coordinates. Next, I list the most commonly used name (or alias), then I list the variable star designation if it is available. If not, I list the constellation name and a V** or?? depending on what the last designated variable star for that constellation is. I present epoch 2000 coordinates for all of the stars, which I precessed from the 1950 ones in most cases. I do not include proper motion effects; this is negligible for all except the largest proper motion DAV stars, such as L 19-2, BPM 37093, B 808, and G 29-38. Even in these cases, the error is no more than 30` in declination and 2 s in right ascension. I culled effective temperatures from the latest work (listed under each table); they are now much more homogeneous than before. I pulled the magnitude estimates from the appropriate paper, and they are mean values integrated over several cycles. The amplitude given is for the height of a typical pulse in the light curve. The periods correspond the dominant ones found in the light curve. In some cases, there is a band of power in a given period range, or the light curve is very complex, and I indicate this in the table. In the references, I generally list the paper with the most comprehensive pulsation analysis for the star in question. In some cases, there is more than one good reference, and I list them as well.

Bradley, P. A.

1997-12-31T23:59:59.000Z

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.


421

Retrieval of hourly records of surface hydrometeorological variables using satellite remote sensing data  

Science Journals Connector (OSTI)

A new algorithm is formulated for retrieving hourly time-series of surface hydrometeorological variables including net radiation, sensible heat flux, and near-surface air temperature aided by hourly visible images from the Geostationary ...

Sanaz Moghim; Andrew Jay Bowen; Sepideh Sarachi; Jingfeng Wang

422

Direct comparison of Neural Network, Fuzzy Logic and Model Prediction Variable Structure vortex flow controllers  

E-Print Network (OSTI)

Predictive Variable Structure and Fuzzy Logic based controllers for the same benchmark problem. Evaluation criteria consist of closed-loop system performance, activity level of the VFC nozzles, ease of controller synthesis, time required to synthesize...

Joshi, Praveen Sudhakar

2012-06-07T23:59:59.000Z

423

Testing, Model Simulations of the Thermocline Depth Variability in the Tropical Atlantic from 1982 through 1984  

Science Journals Connector (OSTI)

The multivariate model toning procedure of Frankignoul et al. has been extended to the general time-series case, thus allowing to test ocean model ability at simulating the interannual variability. The method aims at distinguishing between model ...

Pascale Braconnot; Claude Frankignoul

1993-04-01T23:59:59.000Z

424

New method to obtain the power spectra of hidden variables and its application to ocean data  

Science Journals Connector (OSTI)

A novel method is proposed to obtain the power spectra of hidden variables in a chaotic time series. By embedding the data in phase space, and recording the conditional probability density of points that the t...

Wei en-bo; Tian Ji-wei; Xu Jin-shan

2001-03-01T23:59:59.000Z

425

Invariant formulation for dispersed transverse isotropy in aortic heart valves: An efficient means for modeling fiber splay  

SciTech Connect

Most soft tissues possess an oriented architecture of collagen fiber bundles, conferring both anisotropy and nonlinearity to their elastic behavior. Transverse isotropy has often been assumed for a subset of these tissues that have a single macroscopically-identifiable preferred fiber direction. Micro-structural studies, however, suggest that, in some tissues, collagen fibers are approximately normally distributed about a mean preferred fiber direction. Structural constitutive equations that account for this dispersion of fibers have been shown to capture the mechanical complexity of these tissues quite well. Such descriptions, however, are computationally cumbersome for two-dimensional (2D) fiber distributions, let alone for fully three-dimensional (3D) fiber populations. In this paper, we develop a new constitutive law for such tissues, based on a novel invariant theory for dispersed transverse isotropy. The invariant theory is based on a novel closed-form ''splay invariant'' that can easily handle 3D fiber populations, and that only requires a single parameter in the 2D case. The model is polyconvex and fits biaxial data for aortic valve tissue as accurately as the standard structural model. Modification of the fiber stress-strain law requires no re-formulation of the constitutive tangent matrix, making the model flexible for different types of soft tissues. Most importantly, the model is computationally expedient in a finite-element analysis, demonstrated by modeling a bioprosthetic heart valve.

Freed, Alan D.; Einstein, Daniel R.; Vesely, Ivan

2005-11-01T23:59:59.000Z

426

Development and modification of a single overhead camshaft 4-valve 4-stroke 135 cc formula varsity race car engine  

Science Journals Connector (OSTI)

The engine that was chosen to be developed and modified is Yamaha LC 135 Single Overhead Camshaft (SOHC) 4-valve 4-stroke 135cc liquid-cooled engine. The engine selection is based on the specification, rule and regulation in UTeM Formula Varsity 2012 (FV 2012). The engine performance is determined by engine operating characteristics. The engine air flow affects the filtration, intake and exhaust systems. The heat from the engine rejected to the surrounding through the active cooling system which has radiator and fan. The selection of the engine is based on weighted decision matrix which consists of reliability, operating and maintenance cost, fuel consumption and weight. The score of the matrix is formulated based on relative weighted factor among the selections. It been compared between Yamaha LC 135 Single Overhead Camshaft (SOHC) 4-valve 4-stroke 135cc liquid-cooled engine, Honda Wave 125 X Air Cooled, 4 Cycle Engine Overhead Camshaft (OHC) and Suzuki Shogun RR 4 stroke air cooled Single Overhead Camshaft (SOHC). The modification is applied to the engine through the simulation and tuning of Capacitor Discharge Ignition (CDI).

M A Abdullah; N Tamaldin; H Rusnandi; T Manoharan; M A Samsir

2013-01-01T23:59:59.000Z

427

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time  

E-Print Network (OSTI)

Female Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Amy:56:27.6 Deborah Mc Eligot Deborah Storrings Male Team Overall Name Age Rank Time Rank Time Rank Time Pace Rank Time Rank Time Pace Time 1 Macon Fessenden 20 1 5:42.2 2 0:26.9 1 34:29.7 3:23 1 0:12.8 1 17:41.1 3

Suzuki, Masatsugu

428

Timing of operation for aortic regulation: Relation to postoperative contractile state  

Science Journals Connector (OSTI)

With angiography and pressure measurement, we determined left ventricular volume, wall stress, and systolic performance in 30 patients with aortic regurgitation before and after successful aortic valve replacement. End-systolic wall stress was greatly elevated preoperatively and decreased to normal postoperatively. Systolic pump performance assessed as ejection phase indexes was severely depressed preoperatively and improved to normal or near-normal postoperatively in most patients. The ratio of end-systolic wall stress to end-systolic volume index (ESS/ESVI), an index of myocardial contractility, was greatly decreased before operation. Postoperatively, the ratio increased in all patients, becoming normal in 12 of the 13 patients who had a preoperative ESS/ESVI of 2.9 or greater. However, 15 of 17 patients in whom the ESS/ESVI ratio was less than 2.9 still had subnormal ratios, which indicates the presence of irreversible contractile dysfunction. Stepwise multivariate analysis showed that preoperative ESS/ESVI was the only independent discriminator of postoperative normalization of the contractile function as assessed by ESS/ ESVI. After aortic valve replacement, myocardial contractile state does not return to normal in a considerable number of patients. It is important to offer aortic valve replacement for aortic regurgitation before the chance for a good functional result is lost. The ESS/ESVI ratio may be a useful index in determining the timing of operation in patients with aortic regurgitation.

Kazuhiro Taniguchi; Susumu Nakano; Hikaru Matsuda; Yasuhisa Shimazaki; Kei Sakai; Tomohide Kawamoto; Shigehiko Sakaki; Junjiro Kobayashi; Hideo Shintani; Masataka Mitsuno; Yasunaru Kawashima

1990-01-01T23:59:59.000Z

429

Long-Period Solar Variability  

SciTech Connect

Terrestrial climate records and historical observations of the Sun suggest that the Sun undergoes aperiodic oscillations in radiative output and size over time periods of centuries and millenia. Such behavior can be explained by the solar convective zone acting as a nonlinear oscillator, forced at the sunspot-cycle frequency by variations in heliomagnetic field strength. A forced variant of the Lorenz equations can generate a time series with the same characteristics as the solar and climate records. The timescales and magnitudes of oscillations that could be caused by this mechanism are consistent with what is known about the Sun and terrestrial climate.

GAUTHIER,JOHN H.

2000-07-20T23:59:59.000Z

430

Variable path length spectrophotometric probe  

DOE Patents (OSTI)

A compact, variable pathlength, fiber optic probe for spectrophotometric measurements of fluids in situ. The probe comprises a probe body with a shaft having a polished end penetrating one side of the probe, a pair of optic fibers, parallel and coterminous, entering the probe opposite the reflecting shaft, and a collimating lens to direct light from one of the fibers to the reflecting surface of the shaft and to direct the reflected light to the second optic fiber. The probe body has an inlet and an outlet port to allow the liquid to enter the probe body and pass between the lens and the reflecting surface of the shaft. A linear stepper motor is connected to the shaft to cause the shaft to advance toward or away from the lens in increments so that absorption measurements can be made at each of the incremental steps. The shaft is sealed to the probe body by a bellows seal to allow freedom of movement of the shaft and yet avoid leakage from the interior of the probe.

O'Rourke, Patrick E. (157 Greenwood Dr., Martiney, GA 30907); McCarty, Jerry E. (104 Recreation Dr., Aiken, SC 29803); Haggard, Ricky A. (1144 Thornwood Drive, North Augusta, SC 29891)

1992-01-01T23:59:59.000Z

431

HERSCHEL OBSERVATIONS OF CATACLYSMIC VARIABLES  

SciTech Connect

We have used the PACS instrument on the Herschel Space Observatory to observe eight cataclysmic variables at 70 and 160 {mu}m. Of these eight objects, only AM Her was detected. We have combined the Herschel results with ground-based, Spitzer, and WISE observations to construct spectral energy distributions for all of the targets. For the two dwarf novae in the sample, SS Cyg and U Gem, we find that their infrared luminosities are completely dominated by their secondary stars. For the two highly magnetic 'polars' in our survey, AM Her and EF Eri, we find that their mid-infrared excesses, previously attributed to circumbinary dust emission, can be fully explained by cyclotron emission. The WISE light curves for both sources show large, orbitally modulated variations that are identically phased to their near-IR light curves. We propose that significant emission from the lowest cyclotron harmonics (n {<=} 3) is present in EF Eri and AM Her. Previously, such emission would have been presumed to be optically thick, and not provide significant orbitally modulated flux. This suggests that the accretion onto polars is more complicated than assumed in the simple models developed for these two sources. We develop a model for the near-/mid-IR light curves for WZ Sge with an L2 donor star that shows that the ellipsoidal variations from its secondary star are detected. We conclude that none of the targets surveyed have dusty circumbinary disks.

Harrison, Thomas E.; Hamilton, Ryan T. [Department of Astronomy, New Mexico State University, Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Tappert, Claus [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Valparaiso (Chile); Hoffman, Douglas I. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Campbell, Ryan K., E-mail: tharriso@nmsu.edu, E-mail: rthamilt@nmsu.edu, E-mail: claus.tappert@uv.cl, E-mail: dhoffman@ipac.caltech.edu, E-mail: Ryan.Campbell@humobldt.edu [Department of Physics and Astronomy, Humboldt State University, 1 Harpst St., Arcata, CA 95521 (United States)

2013-01-01T23:59:59.000Z

432

Variable-Period Undulators for Synchrotron Radiation  

SciTech Connect

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22T23:59:59.000Z

433

Multivector Functions of a Real Variable  

E-Print Network (OSTI)

This paper is an introduction to the theory of multivector functions of a real variable. The notions of limit, continuity and derivative for these objects are given. The theory of multivector functions of a real variable, even being similar to the usual theory of vector functions of a real variable, has some subtle issues which make its presentation worhtwhile.We refer in particular to the derivative rules involving exterior and Clifford products, and also to the rule for derivation of a composition of an ordinary scalar function with a multivector function of a real variable.

A. M. Moya; V. V. Fernndez; W. A. Rodrigues Jr

2002-12-17T23:59:59.000Z

434

Hybrid Bayesian Networks with Linear Deterministic Variables  

E-Print Network (OSTI)

Conference (UAI-05), 2005, AUAI Press, Arlington, VA. 136 Y X Z Figure 2: A Bayesian Network Representation of the Mixed Distribution for X. this example, Y is a discrete variable with state space ? Y = {1,2,3}, Z is a real-valued variable, and X is a... conditionally deterministic variable whose condi- tional distribution is described as follows: X |{y,z} = y if y =1,2 and X |{y,z} = z if y =3. Potentials of the type described above are used in this paper to represent distributions of variables in hy- brid...

Cobb, Barry R.; Shenoy, Prakash P.

2005-07-01T23:59:59.000Z

435

Integrating Variable Renewable Energy: Challenges and Solutions  

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

Integrating Variable Renewable Energy: Challenges and Solutions L. Bird, M. Milligan, and D. Lew National Renewable Energy Laboratory Technical Report NRELTP-6A20-60451 September...

436

Materials Science and Engineering B 117 (2005) 5361 Finite element analysis-based design of a fluid-flow control nano-valve  

E-Print Network (OSTI)

of a fluid-flow control nano-valve M. Grujicica,, G. Caoa, B. Pandurangana, W.N. Royb a Department A finite element method-based procedure is developed for the design of molecularly functionalized nano-size devices. The procedure is aimed at the single-walled carbon nano-tubes (SWCNTs) used in the construction

Grujicic, Mica

437

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

438

Dark matter interacts with variable vacuum energy  

E-Print Network (OSTI)

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) scenario with two interacting components, dark matter and variable vacuum energy (VVE) densities, plus two decoupled components, one is a baryon term while the other behaves as a radiation component. We consider a linear interaction in the derivative dark component density. We apply the $\\chi^2$ method to the observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era for the model. It turns out that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)measurements from Planck survey, the future constraints achievable by Euclid and CMBPol experiments, reported for the behavior of the dark energy at early times, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at $2\\sigma$ level in the big-bang nucleosynthesis epoch. We also examine the cosmic age problem at high redshift associated with the old quasar APM 08279+5255 and estimate the age of the universe today.

Ivn E. Snchez G

2014-05-06T23:59:59.000Z

439

Envera Variable Compression Ratio Engine  

SciTech Connect

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new technologies are packaged together to provide the greatest gains at the least cost. Aggressive engine downsiz

Charles Mendler

2011-03-15T23:59:59.000Z

440

Total Solar Irradiance Variability and the Solar Activity Cycle  

E-Print Network (OSTI)

It is suggested that the solar variability is due to the perturbed nature of the solar core and this variability is provided by the variability of the solar neutrino flux from the solar neutrino detectors i.e., Homestake, Superkamiokande, SAGE and GALLEX-GNO. The solar neutrino flux in the standard solar model (SSM) was calculated on the assumption of L_nu (neutrino luminosity) = L_gamma (optical luminosity) which implies that if there is a change in optical luminosity then solar neutrino flux data will also be changed. An internal dynamo due to the cyclic variation of nuclear energy generation inside the core of the sun is responsible for the solar activity cycle was suggested and thus the internal magnetic field is also variable. Again the changes in the nuclear energy generation induce structural changes that result in variations of the global solar parameters i.e., luminosity, radius and temperatures etc. From the analysis of total solar irradiance (TSI) data during the year from 1970 to 2003 we have found five phases within the solar activity cycle. The first phase (I) starts before two years from the sunspot minimum. The second phase (II) starts at the time of sunspot minimum and phase (III) starts before 2/3 years from sunspot maximum whereas phase (IV) starts at sunspot maximum and fifth phase (V) starts at after 2-3 years from sunspot maximum.

Probhas Raychaudhuri

2006-05-06T23:59:59.000Z

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441

Deutsch-Jozsa algorithm for continuous variables  

E-Print Network (OSTI)

We present an idealized quantum continuous variable analog of the Deutsch-Jozsa algorithm which can be implemented on a perfect continuous variable quantum computer. Using the Fourier transformation and XOR gate appropriate for continuous spectra we show that under ideal operation to infinite precision that there is an infinite reduction in number of query calls in this scheme.

Arun K. Pati; Samuel L. Braunstein

2002-07-18T23:59:59.000Z

442

Quantum Computing and Hidden Variables Scott Aaronson #  

E-Print Network (OSTI)

Quantum Computing and Hidden Variables Scott Aaronson # Institute for Advanced Study, Princeton of a hidden variable, then we could e#ciently solve problems that are believed to be intractable even powerful than the quantum computing model. PACS numbers: 03.65.Ta, 03.65.Ud, 03.67.Lx, 02.70.­c I

Aaronson, Scott

443

The Cosmological Constant Problem and Re-interpretation of Time  

E-Print Network (OSTI)

We abandon the interpretation that time is a global parameter in quantum mechanics, replace it by a quantum dynamical variable playing the role of time. This operational re-interpretation of time provides a solution to the cosmological constant problem. The expectation value of the zero-point energy under the new time variable vanishes. The fluctuation of the vacuum energy as the leading contribution to the gravitational effect gives a correct order to the observed "dark energy". The "dark energy" as a mirage is always seen comparable with the matter energy density by an observer using the internal clock time. Conceptual consequences of the re-interpretation of time are also discussed.

M. J. Luo

2013-12-10T23:59:59.000Z

444

Closed bore XMR (CBXMR) systems for aortic valve replacement: Investigation of rotating-anode x-ray tube heat loadability  

SciTech Connect

In order to improve the safety and efficacy of percutaneous aortic valve replacement procedures, a closed bore hybrid x-ray/MRI (CBXMR) system is proposed in which an x-ray C-arm will be positioned with its isocenter {approx_equal}1 m from the entrance of a clinical MRI scanner. This system will harness the complementary strengths of both modalities to improve clinical outcome. A key component of the CBXMR system will be a rotating anode x-ray tube to produce high-quality x-ray images. There are challenges in positioning an x-ray tube in the magnetic fringe field of the MRI magnet. Here, the effects of an external magnetic field on x-ray tube induction motors of radiography x-ray tubes and the corresponding reduction of x-ray tube heat loadability are investigated. Anode rotation frequency f{sub anode} was unaffected when the external magnetic field B{sub b} was parallel to the axis of rotation of the anode but decreased when B{sub b} was perpendicular to the axis of rotation. The experimental f{sub anode} values agreed with predicted values to within {+-}3% over a B{sub b} range of 0-30 mT. The MRI fringe field at the proposed location of the x-ray tube mounted on the C-arm ({approx_equal}4 mT) reduced f{sub anode} by only 1%, so x-ray tube heat loadability will not be compromised when using CBXMR systems for percutaneous aortic valve replacement procedures. Eddy current heating power in the rotor due to an MRI fringe field was found to be two orders of magnitude weaker than the heating power produced on the anode due to a fluoroscopic exposure, so eddy current heating had no effect on x-ray tube heat loadability.

Bracken, John A.; Lillaney, Prasheel V.; Fahrig, Rebecca; Rowlands, J. A. [Sunnybrook Health Sciences Center, Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada); Department of Radiology, Lucas MRS Center, Stanford University, 1201 Welch Road, Stanford, California 94305-5488 (United States); Sunnybrook Health Sciences Center, Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada)

2008-09-15T23:59:59.000Z

445

The Energy-Dependence of GRB Minimum Variability Timescales  

E-Print Network (OSTI)

We constrain the minimum variability timescales for 938 GRBs observed by the Fermi/GBM instrument prior to July 11, 2012. The tightest constraints on progenitor radii derived from these timescales are obtained from light curves in the hardest energy channel. In the softer bands -- or from measurements of the same GRBs in the hard X-rays from Swift -- we show that variability timescales tend to be a factor 2--3 longer. Applying a survival analysis to account for detections and upper limits, we find median minimum timescale in the rest frame for long-duration and short-duration GRBs of 45 ms and 10 ms, respectively. Fewer than 10% of GRBs show evidence for variability on timescales below 2 ms. These shortest timescales require Lorentz factors $\\gtrsim 400$ and imply typical emission radii $R \\approx 1 {\\times} 10^{14}$ cm for long-duration GRBs and $R \\approx 3 {\\times} 10^{13}$ cm for short-duration GRBs. We discuss implications for the GRB fireball model and investigate whether GRB minimum timescales evolve w...

Golkhou, V Zach; Littlejohns, Owen M

2015-01-01T23:59:59.000Z

446

SLUDGE BATCH 7B GLASS VARIABILITY STUDY  

SciTech Connect

The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 7b (SB7b). In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frits 418 with a 6% Na{sub 2}O addition (26 wt% Na{sub 2}O in sludge) and 702 with a 4% Na{sub 2}O addition (24 wt% Na{sub 2}O in sludge) to process SB7b. This recommendation was based on assessments of the compositional projections for SB7b available at the time from the Savannah River Remediation (SRR). To support qualification of SB7b, SRNL executed a variability study to assess the applicability of the current durability models for SB7b. The durability models were assessed over the expected composition range of SB7b, including potential caustic additions, combined with Frits 702 and 418 over a 32-40% waste loading (WL) range. Thirty four glasses were selected based on Frits 418 and 702 coupled with the sludge projections with an additional 4-6% Na{sub 2}O to reflect the potential caustic addition. Six of these glasses, based on average nominal sludge compositions including the appropriate caustic addition, were developed for both Frit 418 and Frit 702 at 32, 36 and 40% WL to provide coverage in the center of the anticipated SB7b glass region. All glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). To comply with the DWPF Glass Product Control Program, a total of thirty four glasses were fabricated to assess the applicability of the current DWPF PCCS durability models. Based on the measured PCT response, all of the glasses were acceptable with respect to the Environmental Assessment (EA) benchmark glass regardless of thermal history. The NL[B] values of the SB7b variability study glasses were less than 1.99 g/L as compared to 16.695 g/L for EA. A small number of the D-optimally selected 'outer layer' extreme vertices (EV) glasses were not predictable using the current Product Composition Control System (PCCS) models for durability, but were acceptable compared to the EA glass when tested. These glasses fell outside of the lower 95% confidence band, which demonstrates conservatism in the model. A few of the glasses fell outside of the upper 95% confidence band; however, these particular glasses have normalized release values that were much lower than the values of EA and should be of no practical concern. Per the requirements of the DWPF Glass Product Control Program, the PCCS durability models have been shown to be applicable to the SB7b sludge system with a range of Na{sub 2}O concentrations blended with Frits 418 or 702. PCT results from the glasses fabricated as part of the variability study were shown to be predictable by the current DWPF PCCS models and/or acceptable with respect to the EA benchmark glass regardless of thermal history or compositional view.

Johnson, F.; Edwards, T.

2011-10-25T23:59:59.000Z

447

Optical and X-ray Variability of AGNs  

E-Print Network (OSTI)

I present new comparisons of AGN optical, UV, and X-ray variations. These reveal complex relationships between the different passbands that can change with time in a given object. While there is evidence from several objects that X-ray and optical activity levels are correlated on long timescales, variations on shorter timescales can occur independently. It is proposed that the combination of correlated and uncorrelated short-timescale variability is a consequence of anisotropic high-energy emission. It is also argued that the correlation between X-ray and optical variability on long timescales must be due to a common underlying factor and not to reprocessing of X-ray radiation.

C. Martin Gaskell

2006-12-30T23:59:59.000Z

448

The Deep Lens Survey Transient Search. I. Short Timescale and Astrometric Variability  

Science Journals Connector (OSTI)

We report on the methodology and first results from the Deep Lens Survey (DLS) transient search. We utilize image subtraction on survey data to yield all sources of optical variability down to 24th magnitude. Images are analyzed immediately after acquisition, at the telescope, and in near-real time, to allow for follow-up in the case of time-critical events. All classes of transients are posted to the World Wide Web upon detection. Our observing strategy allows sensitivity to variability over several decades in timescale. The DLS is the first survey to classify and report all types of photometric and astrometric variability detected, including solar system objects, variable stars, supernovae, and short timescale phenomena. Three unusual optical transient (OT) events were detected, flaring on 1000 s timescales. All three events were seen in the B passband, suggesting blue color indices for the phenomena. One event (OT 20020115) is determined to be from a flaring Galactic dwarf star of spectral type dM4. From the remaining two events, we find an overall rate of ? = 1.4eventsdeg-2day-1 on 1000 s timescales, with a 95% confidence limit of ? R passband yields an upper 95% confidence limit on short-timescale astronomical variability in the range 19.5 R R -2day-1. We report also on our ensemble of astrometrically variable objects, as well as an example of photometric variability with an undetected precursor.

A. C. Becker; D. M. Wittman; P. C. Boeshaar; A. Clocchiatti; I. P. Dell'Antonio; D. A. Frail; J. Halpern; V. E. Margoniner; D. Norman; J. A. Tyson; R. A. Schommer

2004-01-01T23:59:59.000Z

449

The relationship of physical training and time components of the left ventricle  

E-Print Network (OSTI)

with the opening of the semilunar valves and simultaneous rise of the aortic pressure (11). The pre-ejection period (PEP), also designated as the total iso- metric period, is the time from onset of excitation to onset of e3ection. This is usually measured... relationship between heart rate and length of tension period has been denied by several investigators (17, 24, 25). However, Maher (16) could statistically demonstrate a definite shor ten- ing to TP with exercise. Shkhvatsabaya (21) found a decrease in TP...

Bradley, Patrick Walton

2012-06-07T23:59:59.000Z

450

Hybrid permanent magnet and variable reluctance generator  

SciTech Connect

This patent describes a hybrid electrical generator. It comprises: a permanent magnet generator having a permanent magnet rotor mounted on a shaft, the permanent magnet generator providing an output voltage over an operating range which falls in response to an increasing electrical load; a variable reluctance generator having a rotor mounted on the shaft with excitation of a stator of the variable reluctance generator being provided from the permanent magnet generator, the variable reluctance generator providing an output voltage which varies in response to an increasing electrical load over an operating range; and a voltage regulator, responsive to combined output voltages of the generators, for controlling the output voltage provided by the variable reluctance generator.

Vaidya, J.; Belanger, D.J.

1990-09-25T23:59:59.000Z

451

Variable Temperature Scanning Probe Microscope | EMSL  

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

EMSL's ultra-high vacuum, variable-temperature scanning probe microscope system, or UHV VT SPM, is a state-of-the-art surface science tool comprising multiple complementary...

452

Buoyancy-generated variable-density turbulence  

SciTech Connect

Both a one-point (engineering) and a two-point (spectral) model are tested against numerical data. Deficiencies in these variable-density models are disucssed and modifications are suggested. Attention is restricted to turbulent interactions of two miscible, incompressible Newtonian fluids of different densities. Departures from the limits of validity of the Boussinesq approximation are examined. Results of the buoyancy-generated turbulence are compared with variable-density model predictions. 3 figs, 6 refs.

Sandoval, D.L. [Los Alamos National Lab., NM (United States)]|[Washington Univ. (United States); Clark, T.T. [Los Alamos National Lab., NM (United States); Riley, J.J. [Washington Univ. (United States)

1996-06-01T23:59:59.000Z

453

Prctica 2. Anlisi descriptiva univariable: variables qualitatives  

E-Print Network (OSTI)

nominal SEXO. Codificada de tipus "numèrica" amb valors 1 i 2. Aquests valors s'etiqueten amb: 1 `Hombre": (1) Seleccionem la variable sexo i la col·loquem al requadre de "Variables". D'aquesta manera obtenim: Frecuencias [Conjunto_de_datos1] C:\\Archivos de programa\\SPSS\\GSS93 reducido.sav Estadísticos sexo Sexo del

Castellana, Natàlia

454

Prctica 2. Anlisi descriptiva univariable: variables qualitatives  

E-Print Network (OSTI)

nominal SEXO. Codificada de tipus "numèrica" amb valors 1 i 2. Aquests valors s'etiqueten amb: 1 `Hombre) Seleccionem la variable sexo i la col·loquem al requadre de "Variables". D'aquesta manera obtenim la taula de Estadísticos Sexo del entrevistado 1500 0 2 Válidos Perdidos N Moda sexo Sexo del entrevistado 641 42,7 42,7 42

Castellana, Natàlia

455

Property:Real-Time | Open Energy Information  

Open Energy Info (EERE)

Real-Time Real-Time Jump to: navigation, search Property Name Real-Time Property Type String Pages using the property "Real-Time" Showing 25 pages using this property. (previous 25) (next 25) 1 1.5-ft Wave Flume Facility + No + 10-ft Wave Flume Facility + No + 11-ft Wave Flume Facility + No + 2 2-ft Flume Facility + No + 3 3-ft Wave Flume Facility + No + 5 5-ft Wave Flume Facility + No + 6 6-ft Wave Flume Facility + No + A Alden Large Flume + Yes + Alden Small Flume + Yes + Alden Tow Tank + Yes + Alden Wave Basin + Yes + B Breakwater Research Facility + No + Bucknell Hydraulic Flume + No + C Carderock 2-ft Variable Pressure Cavitation Water Tunnel + No + Carderock 3-ft Variable Pressure Cavitation Water Tunnel + No + Carderock Circulating Water Channel + No +

456

Polynomial Time Algorithms for Stochastic Uncapacitated Lot-Sizing ...  

E-Print Network (OSTI)

V(j). 1. Figure 1: Multi-stage stochastic scenario tree formulation of the tree gives the state ... indicator variable for a production setup in time period t(i) for node i.

2007-07-13T23:59:59.000Z

457

Deconvolution of variability and uncertainty in the Cassini safety analysis  

SciTech Connect

The standard method for propagation of uncertainty in a risk analysis requires rerunning the risk calculation numerous times with model parameters chosen from their uncertainty distributions. This was not practical for the Cassini nuclear safety analysis, due to the computationally intense nature of the risk calculation. A less computationally intense procedure was developed which requires only two calculations for each accident case. The first of these is the standard 'best-estimate' calculation. In the second calculation, variables and parameters change simultaneously. The mathematical technique of deconvolution is then used to separate out an uncertainty multiplier distribution, which can be used to calculate distribution functions at various levels of confidence.

Kampas, Frank J.; Loughin, Stephen [Lockheed Martin Missiles and Space, P.O. Box 8555, Philadelphia, Pennsylvania 19101 (United States); WAM Systems, 650 Loraine Street, Ardmore, Pennsylvania 19003 (United States)

1998-01-15T23:59:59.000Z

458

CIP methods for hyperbolic system with variable and discontinuous coefficient  

E-Print Network (OSTI)

We propose a multi-moment method for one-dimensional hyperbolic equations with smooth coefficient and piecewise constant coefficient. The method is entirely based on the backward characteristic method and uses the solution and its derivative as unknowns and cubic Hermite interpolation for each computational cell. The exact update formula for solution and its derivative is derived and used for an efficient time integration. At points of discontinuity of wave speed we define a piecewise cubic Hermite interpolation based on immersed interface method. The method is extended to the one-dimensional Maxwell's equations with variable material properties.

Ito, Kazufumi

2011-01-01T23:59:59.000Z

459

Nonlinear time-fractional dispersive equations  

E-Print Network (OSTI)

In this paper we study some cases of time-fractional nonlinear dispersive equations (NDEs) involving Caputo derivatives, by means of the invariant subspace method. This method allows to find exact solutions to nonlinear time-fractional partial differential equations by separating variables. We first consider a third order time-fractional NDE that admits a four-dimensional invariant subspace and we find a similarity solution. We also study a fifth order NDE. In this last case we find a solution involving Mittag-Leffler functions. We finally observe that the invariant subspace method permits to find explicit solutions for a wide class of nonlinear dispersive time-fractional equations.

P. Artale Harris; R. Garra

2014-10-29T23:59:59.000Z

460

Technical evaluation report, TMI action NUREG-0737 (II.D.1), relief and safety valve testing, Comanche Peak, Unit 2, Docket No. 50-446  

SciTech Connect

In the past, safety and relief valves installed in the primary coolant system of light water reactors have performed improperly. As a result, the authors of NUREG-0578 (TMI-2 Lessons Learned Task Force Status Report and Short-Term Recommendations) and, subsequently, NUREG-0737 (Clarification of TMI Action Plan Requirements) recommended development and completion of programs to do two things. First, the programs should reevaluate the functional performance capabilities of pressurized water reactor safety, relief, and block valves. Second, they should verify the integrity of the pressurizer safety and relief valve piping systems for normal, transient, and accident conditions. This report documents the review of those programs by EG&G Idaho, Inc. Specifically, this report documents the review of the Comanche Peak, Unit 2, Applicant response to the requirements of NUREG-0578 and NUREG-0737. This review found the Applicant provided an acceptable response reconfirming they met General Design Criteria 14, 15, and 30 of Appendix A to 10 CFR 50 for the subject equipment.

Fineman, C.P.

1993-01-01T23:59:59.000Z

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


461

Cloud speed impact on solar variability scaling ?? Application to the wavelet variability model  

E-Print Network (OSTI)

Kleissl, J. , 2013. Deriving cloud velocity from an array ofCloud Speed Impact on Solar Variability Scaling -this work, we determine from cloud speeds. Cloud simulator

Lave, Matthew; Kleissl, Jan

2013-01-01T23:59:59.000Z

462

Control of Decadal and Bidecadal Climate Variability in the Tropical Pacific by the Off-Equatorial South Pacific Ocean  

Science Journals Connector (OSTI)

Delayed negative feedback processes determining intrinsic decadal and bidecadal time scales for the tropical variability in the Pacific are investigated based on climate model experiments. By comparing a control run driven by preindustrial forcing ...

Hiroaki Tatebe; Yukiko Imada; Masato Mori; Masahide Kimoto; Hiroyasu Hasumi

2013-09-01T23:59:59.000Z

463

On the practice of dichotomization of quantitative variables  

E-Print Network (OSTI)

The authors examine the practice of dichotomization of quantitative measures, wherein relationships among variables are examined after 1 or more variables have been converted to dichotomous variables by splitting the sample ...

MacCallum, R. C.; Zhang, S.; Preacher, K. J.; Rucker, D. D.

2002-01-01T23:59:59.000Z

464

The use of 'race' as a variable in biomedical research  

E-Print Network (OSTI)

be used as a variable in biomedical research but mainly toRace as a Variable in Biomedical Research A dissertationRace as a Variable in Biomedical Research. Manifest,

Efstathiou, Sophia

2009-01-01T23:59:59.000Z

465

Mass Market Demand Response and Variable Generation Integration Issues: A  

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

Mass Market Demand Response and Variable Generation Integration Issues: A Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study Title Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study Publication Type Report Refereed Designation Unknown Year of Publication 2011 Authors Cappers, Peter, Andrew D. Mills, Charles A. Goldman, Ryan H. Wiser, and Joseph H. Eto Pagination 76 Date Published 10/2011 Publisher LBNL City Berkeley Keywords demand response, electricity markets and policy group, energy analysis and environmental impacts department, renewable generation integration, smart grid Abstract The penetration of renewable generation technology (e.g., wind, solar) is expected to dramatically increase in the United States during the coming years as many states are implementing policies to expand this sector through regulation and/or legislation. It is widely understood, though, that large scale deployment of certain renewable energy sources, namely wind and solar, poses system integration challenges because of its variable and often times unpredictable production characteristics (NERC, 2009). Strategies that rely on existing thermal generation resources and improved wind and solar energy production forecasts to manage this variability are currently employed by bulk power system operators, although a host of additional options are envisioned for the near future. Demand response (DR), when properly designed, could be a viable resource for managing many of the system balancing issues associated with integrating large-scale variable generation (VG) resources (NERC, 2009). However, demand-side options would need to compete against strategies already in use or contemplated for the future to integrate larger volumes of wind and solar generation resources. Proponents of smart grid (of which Advanced Metering Infrastructure or AMI is an integral component) assert that the technologies associated with this new investment can facilitate synergies and linkages between demand-side management and bulk power system needs. For example, smart grid proponents assert that system-wide implementation of advanced metering to mass market customers (i.e., residential and small commercial customers) as part of a smart grid deployment enables a significant increase in demand response capability.1 Specifically, the implementation of AMI allows electricity consumption information to be captured, stored and utilized at a highly granular level (e.g., 15-60 minute intervals in most cases) and provides an opportunity for utilities and public policymakers to more fully engage electricity customers in better managing their own usage through time-based rates and near-real time feedback to customers on their usage patterns while also potentially improving the management of the bulk power system. At present, development of time-based rates and demand response programs and the installation of variable generation resources are moving forward largely independent of each other in state and regional regulatory and policy forums and without much regard to the complementary nature of their operational characteristics.2 By 2020, the electric power sector is expected to add ~65 million advanced meters3 (which would reach ~47% of U.S. households) as part of smart grid and AMI4 deployments (IEE, 2010) and add ~40-80 GW of wind and solar capacity (EIA, 2010). Thus, in this scoping study, we focus on a key question posed by policymakers: what role can the smart grid (and its associated enabling technology) play over the next 5-10 years in helping to integrate greater penetration of variable generation resources by providing mass market customers with greater access to demand response opportunities? There is a well-established body of research that examines variable generation integration issues as well as demand response potential, but the nexus between the two has been somewhat neglected by the industry. The studies that have been conducted are informative concerning what could be accomplished with strong broad-based support for the expansion of demand response opportunities, but typically do not discuss the many barriers that stand in the way of reaching this potential. This study examines how demand side resources could be used to integrate wind and solar resources in the bulk power system, identifies barriers that currently limit the use of demand side strategies, and suggests several factors that should be considered in assessing alternative strategies that can be employed to integrate wind and solar resources in the bulk power system. It is difficult to properly gauge the role that DR could play in managing VG integration issues in the near future without acknowledging and understanding the entities and institutions that govern the interactions between variable generation and mass market customers (see Figure ES-1). Retail entities, like load-serving entities (LSE) and aggregators of retail customers (ARC), harness the demand response opportunities of mass market customers through tariffs (and DR programs) that are approved by state regulatory agencies or local governing entities (in the case of public power). The changes in electricity consumption induced by DR as well as the changes in electricity production due to the variable nature of wind and solar generation technologies is jointly managed by bulk power system operators. Bulk power system operators function under tariffs approved by the Federal Energy Regulatory Commission (FERC) and must operate their systems in accordance with rules set by regional reliability councils. These reliability rules are derived from enforceable standards that are set by the North American Electric Reliability Corporation (NERC) and approved by federal regulators. Thus, the role that DR can play in managing VG integration issues is contingent on what opportunities state and local regulators are willing to approve and how customers' response to the DR opportunities can be integrated into the bulk power system both electrically (due to reliability rules) and financially (due to market rules).

466

Preventing Quantum Hacking in Continuous Variable Quantum Key Distribution  

Science Journals Connector (OSTI)

Security loopholes have been shown for discrete-variable Quantum Key Distribution (QKD). Here, we propose and provide experimental evidence of an attack targeting a continuous-variable...

Jouguet, Paul; Diamanti, Eleni; Kunz-Jacques, Sbastien

467

Impact of Real Field Diesel Quality Variability on Engine Emissions...  

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

Real Field Diesel Quality Variability on Engine Emissions and Fuel Consumption Solutions for Onboard Optimisation Impact of Real Field Diesel Quality Variability on Engine...

468

Adaptation to Climate Variability and Change: A Guidance Manual...  

Open Energy Info (EERE)

to Climate Variability and Change: A Guidance Manual for Development Planning Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Adaptation to Climate Variability and...

469

Microstructural Response of Variably Hydrated Ca-Rich Montmorillonite...  

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

Microstructural Response of Variably Hydrated Ca-Rich Montmorillonite to Supercritical CO2. Microstructural Response of Variably Hydrated Ca-Rich Montmorillonite to Supercritical...

470

Pitch-variable blazed grating consisting of freestanding silicon beams  

Science Journals Connector (OSTI)

Theoretical analysis is presented for a pitch-variable blazed grating which consists of freestanding silicon beams. The pitch-variable blazed grating is implemented by combining...

Wang, Yongjin; Kanamori, Yoshiaki; Hane, Kazuhiro

2009-01-01T23:59:59.000Z

471

Advanced Variable Speed Air-Source Integrated Heat Pump 2013...  

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

Advanced Variable Speed Air-Source Integrated Heat Pump 2013 Peer Review Advanced Variable Speed Air-Source Integrated Heat Pump 2013 Peer Review Emerging Technologies Project for...

472

Nonmonotone line search methods with variable sample size  

E-Print Network (OSTI)

The nonmonotone line search framework is embedded with a variable sample size ... the line search combines well with the variable sample size scheme as.

2014-02-17T23:59:59.000Z

473

Solutions for Interharmonics in Variable Speed Drives for LNG Plants:.  

E-Print Network (OSTI)

??Variable speed drives can cause components of any frequency known as interharmonics. Large variable speed drives in the order of tens of megawatts can replace (more)

Verhulst, M.P.A.

2011-01-01T23:59:59.000Z

474

INSTALLATION, COMMISSIONING AND TROUBLE SHOOTING OF VARIABLE FREQUENCY DRIVE.  

E-Print Network (OSTI)

??In this thesis, the installation of variable frequency drive on board a ship is introduced briefly. In this particular study the variable frequency drive was (more)

Kuituniemi, Santtu

2013-01-01T23:59:59.000Z

475

Control Strategies for Centrifugal Pumps with Variable Flow Rate...  

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

Control Strategies for Centrifugal Pumps with Variable Flow Rate Requirements Control Strategies for Centrifugal Pumps with Variable Flow Rate Requirements This tip sheet discusses...

476

Variable Renewable Energy: a Regulatory Roadmap (Fact Sheet)...  

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

Variable Renewable Energy: a Regulatory Roadmap Research Highlights There is not a one-size-fits-all approach to the regulation of variable renewable energy (VRE), but...

477

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

E-Print Network (OSTI)

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01T23:59:59.000Z

478

Dynamics and variability of the plasmasphere observed from synchronous orbit  

SciTech Connect

The behavior of the cold ions in the outer plasmasphere is studied using data obtained with the magnetospheric plasma analyzers from multiple geosynchronous satellites. Dense (10-100 cm{sup {minus}3}), cold ({approx}1 eV) regions of plasma are often observed at geosynchronous orbit; in this study the authors refer to these as plasmaspheric intervals. The duration, local time of observation, density variability, and temperature behavior within these regions often depend in a systematic way on geomagnetic and substorm activity. With increasing geomagnetic activity (as indicated by Kp) the plasmaspheric regions are generally observed over shorter durations and at earlier local times. With increasing substorm activity (as indicated by geosynchronous energetic electron injections) the density becomes increasingly variable in these regions. Occasionally, up to order-of-magnitude density variations are observed over several minute timescales corresponding to regions with physical dimensions on the order of 1000 km or less. The appearance of these short-duration, cold-plasma intervals is strongly correlated with energetic ion and electron signatures both at the spacecraft making the plasmaspheric observations and at other spacecraft observing simultaneously in the midnight region. Such energetic particle signatures are indicative of the growth and expansive phase of geomagnetic substorms. The authors conclude that the appearance of these short-duration, plasmaspheric intervals is due to a reconfiguration of the duskside magnetosphere during geomagnetic substorms.

Moldwin, M.B.; Thomsen, M.F.; McComas, D.J.; Reeves, G.D.

1994-11-01T23:59:59.000Z

479

Exploring inequality violations by classical hidden variables numerically  

SciTech Connect

There are increasingly suggestions for computer simulations of quantum statistics which try to violate Bell type inequalities via classical, common cause correlations. The ClauserHorneShimonyHolt (CHSH) inequality is very robust. However, we argue that with the EinsteinPodolskyRosen setup, the CHSH is inferior to the Bell inequality, although and because the latter must assume anti-correlation of entangled photon singlet states. We simulate how often quantum behavior violates both inequalities, depending on the number of photons. Violating Bell 99% of the time is argued to be an ideal benchmark. We present hidden variables that violate the Bell and CHSH inequalities with 50% probability, and ones which violate Bell 85% of the time when missing 13% anti-correlation. We discuss how to present the quantum correlations to a wide audience and conclude that, when defending against claims of hidden classicality, one should demand numerical simulations and insist on anti-correlation and the full amount of Bell violation. -- Highlights: The widely assumed superiority of the CHSH fails in the EPR problem. We simulate Bell type inequalities behavior depending on the number of photons. The core of Bells theorem in the EPR setup is introduced in a simple way understandable to a wide audience. We present hidden variables that violate both inequalities with 50% probability. Algorithms have been supplied in form of Mathematica programs.

Vongehr, Sascha, E-mail: vongehr@usc.edu

2013-12-15T23:59:59.000Z

480

Integrating Variable Renewable Energy: Challenges and Solutions  

SciTech Connect

In the U.S., a number of utilities are adopting higher penetrations of renewables, driven in part by state policies. While power systems have been designed to handle the variable nature of loads, the additional supply-side variability and uncertainty can pose new challenges for utilities and system operators. However, a variety of operational and technical solutions exist to help integrate higher penetrations of wind and solar generation. This paper explores renewable energy integration challenges and mitigation strategies that have been implemented in the U.S. and internationally, including forecasting, demand response, flexible generation, larger balancing areas or balancing area cooperation, and operational practices such as fast scheduling and dispatch.

Bird, L.; Milligan, M.; Lew, D.

2013-09-01T23:59:59.000Z

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


481

Variable pressure power cycle and control system  

DOE Patents (OSTI)

A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.

Goldsberry, Fred L. (Spring, TX)

1984-11-27T23:59:59.000Z

482

An Exploratory Study of Variability in Safety  

E-Print Network (OSTI)

An Exploratory Study of Variability in Safety Culture among Clinician types and Patient Care of the current study was to (a) examine how different types of care providers viewed the safety culture of their unit, and (b) examine the relationship between hospital safety culture and patient satisfaction

von der Heydt, Rüdiger

483

SYNTHESIS: MODELING VARIABILITY AND CONSTRAINTS Rolf Carlson  

E-Print Network (OSTI)

SYNTHESIS: MODELING VARIABILITY AND CONSTRAINTS Rolf Carlson This is a modified version. Abstract This paper discusses some important topics in current speech synthesis research. Modeling of speaker characteristics and emotions are used as a examples of new trends in the speech synthesis field

Carlson, Rolf

484

Galactic Variable Sky with EGRET and GLAST  

SciTech Connect

The characteristics of the largely-unidentified Galactic sources of gamma rays that were detected by EGRET are reviewed. Proposed source populations that may have the correct spatial, spectral, luminosity, and variability properties to be the origins of the EGRET sources are also presented. Finally, the prospects for studying Galactic gamma-ray sources with the GLAST LAT are reviewed.

Digel, S.W.; /SLAC

2006-11-28T23:59:59.000Z

485

Heart Rate Variability Malvin Carl Teich  

E-Print Network (OSTI)

Heart Rate Variability Malvin Carl Teich Boston University and Columbia University http, Grasmere, UK, 2005 #12;CONGESTIVE HEART FAILURE INABILITY OF HEART TO INCREASE CARDIAC OUTPUT IN PROPORTION of breath Swelling in legs General fatigue and weakness Clinical diagnostics: Ascultate heart Carotid pulse

Teich, Malvin C.

486

The QSO variability-luminosity-redshift relation  

Science Journals Connector (OSTI)

......to test Poissonian (or 'Christmas-tree') models for QSO variability...mean B-band luminosity in the light curve and a(LB) is its standard...comparison of the UV and optical light curves of NGC 4151 and 5548...spanning 16 yr. The rest-frame light curves are between 3.2 and......

Roberto Cid Fernandes; Jr; Itziar Aretxaga; Roberto Terlevich

1996-10-11T23:59:59.000Z

487

The Sun is an active, variable,  

E-Print Network (OSTI)

The Sun is an active, variable, magnetic star with oscillations on its surface and deep within its the physical processes of the Sun-Earth connection. Visit Us on the Web: Solar Terrestrial Probes Program: http://stp.gsfc.nasa.gov For More Information, See: Sun-Earth Connection: http://sec.gsfc.nasa.gov Living With a Star: http

Christian, Eric

488

Chapter 18: Variable Frequency Drive Evaluation Protocol  

SciTech Connect

An adjustable-speed drive (ASD) includes all devices that vary the speed of a rotating load, including those that vary the motor speed and linkage devices that allow constant motor speed while varying the load speed. The Variable Frequency Drive Evaluation Protocol presented here addresses evaluation issues for variable-frequency drives (VFDs) installed on commercial and industrial motor-driven centrifugal fans and pumps for which torque varies with speed. Constant torque load applications, such as those for positive displacement pumps, are not covered by this protocol. Other ASD devices, such as magnetic drive, eddy current drives, variable belt sheave drives, or direct current motor variable voltage drives, are also not addressed. The VFD is by far the most common type of ASD hardware. With VFD speed control on a centrifugal fan or pump motor, energy use follows the affinity laws, which state that the motor electricity demand is a cubic relationship to speed under ideal conditions. Therefore, if the motor runs at 75% speed, the motor demand will ideally be reduced to 42% of full load power; however, with other losses it is about 49% of full load power.

Romberger, J.

2014-11-01T23:59:59.000Z

489

Variable Light-Cone Theory of Gravity  

E-Print Network (OSTI)

We show how to reformulate Variable Speed of Light Theories (VSLT) in a covariant fashion as Variable Light-Cone Theories (VLCT) by introducing two vierbein bundles each associated with a distinct metric. The basic gravitational action relates to one bundle while matter propagates relative to the other in a conventional way. The variability of the speed of light is represented by the variability of the matter light-cone relative to the gravitational light-cone. The two bundles are related locally by an element M, of SL(4,R). The dynamics of the field M is that of a SL(4,R)-sigma model gauged with respect to local (orthochronous) Lorentz transformations on each of the bundles. Only the ``massless'' version of the model with a single new coupling, F, that has the same dimensions as Newton's constant $G_N$, is considered in this paper. When F vanishes the theory reduces to standard General Relativity. We verify that the modified Bianchi identities of the model are consistent with the standard conservation law for the matter energy-momentum tensor in its own background metric. The implications of the model for some simple applications are examined, the Newtonian limit, the flat FRW universe and the spherically symmetric static solution.

I. T. Drummond

1999-08-20T23:59:59.000Z

490

Variability viewpoint to describe reference architectures  

Science Journals Connector (OSTI)

Reference architectures have emerged as a special type of software architecture that achieves well-recognized understanding of specific domains. Their purpose is therefore to be a guidance for the development, standardization, and evolution of systems ... Keywords: architecture description, reference architecture, variability

Milena Guessi; Flavio Oquendo; Elisa Yumi Nakagawa

2014-04-01T23:59:59.000Z

491

E85 Optimized Engine through Boosting, Spray-Optimized DIG, VCR and Variable Valvetrain  

SciTech Connect

The use of biofuels for internal combustion engines has several well published advantages. The biofuels, made from biological sources such as corn or sugar cane, are renewable resources that reduce the dependence on fossil fuels. Fuels from agricultural sources can therefore reduce a countries energy dependency on other nations. Biofuels also have been shown to reduce CO2 emissions into the atmosphere compared to traditional fossil based fuels. Because of these benefits several countries have set targets for the use of biofuels, especially ethanol, in their transportation fuels. Small percentages of ethanol are common place in gasoline but are typically limited to 5 to 8% by volume. Greater benefits are possible from higher concentrations and some countries such as the US and Sweden have encouraged the production of vehicles capable of operating on E85 (85% denatured ethanol and 15% gasoline). E85 capable vehicles are normally equipped to run the higher levels of ethanol by employing modified fuel delivery systems that can withstand the highly corrosive nature of the alcohol. These vehicles are not however equipped to take full advantage of ethanol's properties during the combustion process. Ethanol has a much higher blend research octane number than gasoline. This allows the use of higher engine compression ratios and spark advance which result in more efficient engine operation. Ethanol's latent heat of vaporization is also much higher that gasoline. This higher heat of vaporization cools the engine intake charge which also allows the engine compression ratio to be increased even further. An engine that is optimized for operation on high concentrations of ethanol therefore will have compression ratios that are too high to avoid spark knock (pre-ignition) if run on gasoline or a gasoline/ethanol blend that has a low percentage alcohol. An engine was developed during this project to leverage the improved evaporative cooling and high octane of E85 to improve fuel economy and offset E85's lower energy content. A 2.0 L production Direct Injection gasoline, (DIg) engine employing Dual Independent Cam Phasing, (DICP) and turbo charging was used as the base engine. Modified pistons were used to increase the geometric compression ratio from 9.2:1 to 11.85:1 by modifying the pistons and adding advanced valvetrain to proved control of displacement and effective compression ratio through valve timing control. The advanced valvetrain utilized Delphi's two step valvetrain hardware and intake cam phaser with increased phasing authority of 80 crank angle degrees. Using this hardware the engine was capable of operating knock free on all fuels tested from E0-E85 by controlling effective compression ratio using a Late Intake Valve Closing, (LIVC) strategy. The LIVC strategy results in changes in the trapped displacement such that knock limited torque for gasoline is significantly lower than E85. The use of spark retard to control knock enables higher peak torque for knock limited fuels, however a loss in efficiency results. For gasoline and E10 fuels, full effective displacement could not be reached before spark retard produced a net loss in torque. The use of an Early Intake Valve Closing, (EIVC) strategy resulted in an improvement of engine efficiency at low to mid loads for all fuels tested from E0- E85. Further the use of valve deactivation, to a single intake valve, improved combustion stability and enabled throttle-less operation down to less than 2 bar BMEP. Slight throttling to trap internal residual provided additional reductions in fuel consumption. To fully leverage the benefits of E85, or ethanol blends above E10, would require a vehicle level approach that would take advantage of the improved low end torque that is possible with E85. Operating the engine at reduced speeds and using advanced transmissions (6 speeds or higher) would provide a responsive efficient driving experience to the customer. The vehicle shift and torque converter lockup points for high ethanol blends could take advantage of the significant efficiency ad

Keith Confer; Harry Husted