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1

High-Velocity Rocks Final Report  

DOE Green Energy (OSTI)

The objective of our research was to develop and demonstrate seismic data-acquisition and data-processing technologies that allow geothermal prospects below high-velocity rock outcrops to be evaluated. To do this, we acquired a 3-component seismic test line across an area of exposed high-velocity rocks in Brewster County, Texas, where there is high heat flow and surface conditions mimic those found at numerous geothermal prospects. Seismic contractors have not succeeded in creating good-quality seismic data in this area for companies who have acquired data for oil and gas exploitation purposes. Our test profile traversed an area where high-velocity rocks and low-velocity sediment were exposed on the surface in alternating patterns that repeated along the test line. We verified that these surface conditions cause non-ending reverberations of Love waves, Rayleigh waves, and shallow critical refractions to travel across the earth surface between the boundaries of the fast-velocity and slow-velocity material exposed on the surface. These reverberating surface waves form the high level of noise in this area that does not allow reflections from deep interfaces to be seen and utilized. Our data-acquisition method of deploying a box array of closely spaced geophones allowed us to recognize and evaluate these surface-wave noise modes regardless of the azimuth direction to the surface anomaly that backscattered the waves and caused them to return to the test-line profile. With this knowledge of the surface-wave noise, we were able to process these test-line data to create P-P and SH-SH images that were superior to those produced by a skilled seismic data-processing contractor. Compared to the P-P data acquired along the test line, the SH-SH data provided a better detection of faults and could be used to trace these faults upward to the boundaries of exposed surface rocks. We expanded our comparison of the relative value of S-wave and P-wave seismic data for geothermal applications by inserting into this report a small part of the interpretation we have done with 3C3D data across Wister geothermal field in the Imperial Valley of California. This interpretation shows that P-SV data reveal faults (and by inference, also fractures) that cannot be easily, or confidently, seen with P-P data, and that the combination of P-P and P-SV data allows VP/VS velocity ratios to be estimated across a targeted reservoir interval to show where an interval has more sandstone (the preferred reservoir facies). The conclusion reached from this investigation is that S-wave seismic technology can be invaluable to geothermal operators. Thus we developed a strong interest in understanding the direct-S modes produced by vertical-force sources, particularly vertical vibrators, because if it can be demonstrated that direct-S modes produced by vertical-force sources can be used as effectively as the direct-S modes produced by horizontal-force sources, geothermal operators can acquire direct-S data across many more prospect areas than can be done with horizontal-force sources, which presently are limited to horizontal vibrators. We include some of our preliminary work in evaluating direct-S modes produced by vertical-force sources.

Hardage, Bob A; DeAngelo, Michael V; Ermolaeva, Elena; Hardage, Bob A; Remington, Randy; Sava, Diana; Wagner, Donald; Wei, Shuijion

2013-02-28T23:59:59.000Z

2

Perturbations in high-velocity gas flow  

DOE Green Energy (OSTI)

High velocity explosive products or other low-density gases are often used to accelerate metal plates to high velocities. Perturbations in otherwise uniform flow configurations are sometimes sufficient to cause interactions that can rapidly destroy the integrity of the plates. In this study perturbations were introduced in uniform gas flows of detonated HE products and strongly shocked polyethylene, CH{sub 2}. The primary diagnostics were smear-camera records obtained when these gases impinged on layers of plexiglas separated by small argon-filled gaps. These records show shock-arrival times at various levels and thus determine not only the size of the perturbation but also its strength. Perturbations in HE gases running into H{sub 2} and in CH{sub 2} into H{sub 2} have been studied. Two-dimensional hydrodynamic calculations are in excellent agreement with the experiments, and enable one to study details of the flow not possible from experimental results. 1 ref., 5 figs.

Harvey, W.B.; McQueen, R.G. (Los Alamos National Lab., NM (USA))

1989-01-01T23:59:59.000Z

3

Velocity  

Science Conference Proceedings (OSTI)

... Delta t ffl \\Delta t = 1ns. Pulse-Dri ven Wall Motion ( ff = ... varies, can increase (!), eventually decays tozero. Pulse-Dri ven Domain Wall Velocity ( ff = ...

2004-01-16T23:59:59.000Z

4

High Velocity Laser Accelerated Deposition (HVLAD)  

... thus producing a very broad range of advanced high-temperature and corrosion ... from stress corrosion cracking, corrosion fatigue, hydrogen ...

5

Superconducting spoke cavities for high-velocity applications  

SciTech Connect

To date, superconducting spoke cavities have been designed, developed, and tested for particle velocities up to {beta}{sub 0}~0.6, but there is a growing interest in possible applications of multispoke cavities for high-velocity applications. We have explored the design parameter space for low-frequency, high-velocity, double-spoke superconducting cavities in order to determine how each design parameter affects the electromagnetic properties, in particular the surface electromagnetic fields and the shunt impedance. We present detailed design for cavities operating at 325 and 352 MHz and optimized for {beta}{sub 0}~=0.82 and 1.

Hopper, Christopher S. [Old Dominion U.; Delayen, Jean R. [Old Dominion U., JLAB

2013-10-01T23:59:59.000Z

6

The Case of Sharp Velocity Transitions in High Vertical Wind Shear When Measuring Doppler Velocities with Narrow Nyquist Intervals  

Science Conference Proceedings (OSTI)

An investigation was launched following unexpected observations of step-function transitions in Doppler velocities from scanning radars in regions of high vertical wind shear. It revealed that, if wind velocity transitions are sufficiently sharp ...

Frédéric Fabry; Clotilde Augros; Aldo Bellon

2013-03-01T23:59:59.000Z

7

Velocity distribution of high-energy particles and the solar neutrino problem  

E-Print Network (OSTI)

High energy infers high velocity and high velocity is a concept of special relativity. The Maxwellian velocity distribution is corrected to be consistent with special relativity. The corrected distribution reduces to the Maxwellian distribution for small velocities, contains a relatively depleted high-energy tail and vanishes at the velocity of light. This corrected distribution will lower solar neutrino fluxes and change solar neutrino energy spectra but keep solar sound speeds.

Jian-Miin Liu

2001-08-18T23:59:59.000Z

8

Velocity Mapping Capabilities of Present and Future Altimeter Missions: The Role of High-Frequency Signals  

Science Conference Proceedings (OSTI)

A detailed analysis of the velocity field mapping capabilities from existing and future multiple altimeter missions is carried out using the Los Alamos North Atlantic high-resolution model. The velocity mapping errors on the instantaneous fields ...

P. Y. Le Traon; G. Dibarboure

2002-12-01T23:59:59.000Z

9

Low inlet gas velocity high throughput biomass gasifier  

DOE Patents (OSTI)

The present invention discloses a novel method of operating a gasifier for production of fuel gas from carbonaceous fuels. The process disclosed enables operating in an entrained mode using inlet gas velocities of less than 7 feet per second, feedstock throughputs exceeding 4000 lbs/ft.sup.2 -hr, and pressures below 100 psia.

Feldmann, Herman F. (Worthington, OH); Paisley, Mark A. (Upper Arlington, OH)

1989-01-01T23:59:59.000Z

10

Force criterion prediction of damage for carbon/epoxy composite panels impacted by high velocity ice  

E-Print Network (OSTI)

H, Kedward, K. T. Modeling Hail Ice Impacts and PredictingInvestigation of High Velocity Ice Impacts on Woven Carbon/Analysis Correlation of Hail Ice Impacting Composite

Rhymer, Jennifer D.

2012-01-01T23:59:59.000Z

11

Hohlraum Designs for High Velocity Implosions on NIF  

Science Conference Proceedings (OSTI)

In this paper, we compare experimental shock and capsule trajectories to design calculations using the radiation-hydrodynamics code HYDRA. The measured trajectories from surrogate ignition targets are consistent with reducing the x-ray flux on the capsule by about 85%. A new method of extracting the radiation temperature as seen by the capsule from x-ray intensity and image data shows that about half of the apparent 15% flux deficit in the data with respect to the simulations can be explained by HYDRA overestimating the x-ray flux on the capsule. The National Ignition Campaign (NIC) point-design target is designed to reach a peak fuel-layer velocity of 370 km/s by ablating 90% of its plastic (CH) ablator. The 192-beam National Ignition Facility laser drives a gold hohlraum to a radiation temperature (T{sub RAD}) of 300 eV with a 20 ns-long, 420 TW, 1.3 MJ laser pulse. The hohlraum x-rays couple to the CH ablator in order to apply the required pressure to the outside of the capsule. In this paper, we compare experimental measurements of the hohlraum T{sub RAD} and the implosion trajectory with design calculations using the code hydra. The measured radial positions of the leading shock wave and the unablated shell are consistent with simulations in which the x-ray flux on the capsule is artificially reduced by 85%. We describe a new method of inferring the T{sub RAD} seen by the capsule from time-dependent x-ray intensity data and static x-ray images. This analysis shows that hydra overestimates the x-ray flux incident on the capsule by {approx}8%.

Meezan, N B; Hicks, D G; Callahan, D A; Olson, R E; Schneider, M S; Thomas, C A; Robey, H F; Celliers, P M; Kline, J K; Dixit, S N; Michel, P A; Jones, O S; Clark, D S; Ralph, J E; Doeppner, T; MacKinnon, A J; Haan, S W; Landen, O L; Glenzer, S H; Suter, L J; Edwards, M J; Macgowan, B J; Lindl, J D; Atherton, L J

2011-10-19T23:59:59.000Z

12

APPARATUS FOR PRODUCING HIGH VELOCITY SHOCK WAVES IN GASES  

DOE Patents (OSTI)

>A device for producing a high-energy ionized gas region comprises an evacuated tapered insulating vessel and a substantially hemispherical insulating cap hermetically affixed to the large end of the vessel, an annular electrode having a diameter equal to and supported in the interior wall of the vessel at the large end and having a conductive portion inside the vessel, a second electrode supported at the small end of the vessel, means connected to the vessel for introducing a selected gas therein, a source of high potential having two poles. means for connecting one pole of the high potential source to the annular electrode, and means for connecting the other pole of the potential source to the second electrode.

Scott, F.R.; Josephson, V.

1960-02-01T23:59:59.000Z

13

MAGNETIC METHOD FOR PRODUCING HIGH VELOCITY SHOCK WAVES IN GASES  

DOE Patents (OSTI)

A device is described for producing high-energy plasmas comprising a tapered shock tube of dielectric material and having a closed small end, an exceedingly low-inductance coll supported about and axially aligned with the small end of the tapered tube. an elongated multiturn coil supported upon the remninder of the exterior wall of the shock tube. a potential source and switch connected in series with the low-inductance coil, a potential source and switch connected in series with the elongated coil, means for hermetically sealing the large end of the tube, means for purging the tube of gases, and means for admitting a selected gas into the shock tube.

Josephson, V.

1960-01-26T23:59:59.000Z

14

Field-effect transistor having a superlattice channel and high carrier velocities at high applied fields  

DOE Patents (OSTI)

In a field-effect transistor comprising a semiconductor having therein a source, a drain, a channel and a gate in operational relationship, there is provided an improvement wherein said semiconductor is a superlattice comprising alternating quantum well and barrier layers, the quantum well layers comprising a first direct gap semiconductor material which in bulk form has a certain bandgap and a curve of electron velocity versus applied electric field which has a maximum electron velocity at a certain electric field, the barrier layers comprising a second semiconductor material having a bandgap wider than that of said first semiconductor material, wherein the layer thicknesses of said quantum well and barrier layers are sufficiently thin that the alternating layers constitute a superlattice having a curve of electron velocity versus applied electric field which has a maximum electron velocity at a certain electric field, and wherein the thicknesses of said quantum well layers are selected to provide a superlattice curve of electron velocity versus applied electric field whereby, at applied electric fields higher than that at which the maximum electron velocity occurs in said first material when in bulk form, the electron velocities are higher in said superlattice than they are in said first semiconductor material in bulk form.

Chaffin, R.J.; Dawson, L.R.; Fritz, I.J.; Osbourn, G.C.; Zipperian, T.E.

1984-04-19T23:59:59.000Z

15

High velocity impact of metal sphere on thin metallic plates: a comparative smooth particle hydrodynamics study  

Science Conference Proceedings (OSTI)

Four different shock-capturing schemes used in smooth particle hydrodynamics are compared as applied to moderately high-velocity impacts (at 3 km/s) and hypervelocity impacts (at ?6 km/s) of metallic projectiles on thin metal plates. The target ... Keywords: Riemann problem, artificial viscosity, hydrocode, hypervelocity impact

Vishal Mehra; Shashank Chaturvedi

2006-02-01T23:59:59.000Z

16

High Energy Tail of the Velocity Distribution of Driven Inelastic Gases  

E-Print Network (OSTI)

A model of homogeneously driven dissipative system, consisting of a collection of $N$ particles that are characterized by only their velocities, is considered. Adopting a discrete time dynamics, at each time step, a pair of velocities is randomly selected. They undergo inelastic collision with probability $p$. With probability $(1-p)$, energy of the system is changed by changing the velocities of both the particles independently according to $v\\rightarrow -r_w v +\\eta$, where $\\eta$ is a Gaussian noise drawn independently for each particle as well as at each time steps. For the case $r_w=\\pm 1$, although the energy of the system seems to saturate (indicating a steady state) after time steps of O(N), it grows linearly with time after time steps of $O(N^2)$, indicating the absence of a eventual steady state. For $ -1 injection limit, the velocity distribution is shown to be a Gaussian. For the general case, the high energy tail of the velocity distribution is shown to be again a Gaussian, with a different variance.

V. V. Prasad; Sanjib Sabhapandit; Abhishek Dhar

2013-07-12T23:59:59.000Z

17

High-resolution seismic tomography of compressional wave velocity structure at Newberry Volcano, Oregon Cascade Range  

SciTech Connect

Compressional wave velocity structure is determined for the upper crust beneath Newberry Volcano, central Oregon, using a high-resolution active-source seismic-tomography method. Newberry Volcano is a bimodal shield volcano east of the axis of the Cascade Range. It is associated both with the Cascade Range and with northwest migrating silicic volcanism in southeast Oregon. High-frequency (approx.7 Hz) crustal phases, nominally Pg and a midcrustal reflected phase, travel upward through a target volume beneath Newberry Volcano to a dense array of 120 seismographs. This arrangement is limited by station spacing to 1- to 2-km resolution in the upper 5 to 6 km of the crust beneath the volcano's summit caldera. The experiment tests the hypothesis that Cascade Range volcanoes are underlain only by small magma chambers. A small low-velocity anomaly delineated abosut 3 km below the summit caldera supports this hypothesis for Newberry Volcano and is interpreted as a possible magma chamber of a few to a few tens of km/sup 3/ in volume. A ring-shaped high-velocity anomaly nearer the surface coincides with the inner mapped ring fractures of the caldera. It also coincides with a circular gravity high, and we interpret it as largely subsolidus silicic cone sheets. The presence of this anomaly and of silicic vents along the ring fractures suggests that the fractures are a likely eruption path between the small magma chamber and the surface.

Achauer, U.; Evans, J.R.; Stauber, D.A.

1988-09-10T23:59:59.000Z

18

Mapping Metal-Enriched High Velocity Clouds to Very Low HI Column Densities  

E-Print Network (OSTI)

Our galaxy is the nearest known quasar absorption line system, and it uniquely provides us with an opportunity to probe multiple lines of sight through the same galaxy. This is essential for our interpretations of the complex kinematic profiles seen in the MgII absorption due to lines of sight through intermediate redshift galaxies. The Milky Way halo has never been probed for high velocity clouds below the 21-cm detection threshold of N(HI)~10^18 cm-2. Through a survey of MgII absorption looking toward the brightest AGNs and quasars, it will be possible to reach down a few orders of magnitude in HI column density. The analogs to the high velocity components of the MgII absorption profiles due to intermediate redshift galaxies should be seen. We describe a program we are undertaking, and present some preliminary findings.

Chris Churchill; Jane Charlton; Joe Masiero

2001-08-13T23:59:59.000Z

19

Electrical method and apparatus for impelling the extruded ejection of high-velocity material jets  

DOE Patents (OSTI)

A method and apparatus for producing high-velocity material jets is provided. An electric current pulse generator is attached to an end of a coaxial two-conductor transmission line having an outer cylindrical conductor, an inner cylindrical conductor, and a solid plastic or ceramic insulator there between. A coaxial, thin-walled metal structure is conductively joined to the two conductors of the transmission line. An electrical current pulse applies magnetic pressure to and possibly explosively vaporizes metal structure, thereby collapsing it and impelling the extruded ejection of a high-velocity material jet therefrom. The jet is comprised of the metal of the structure, together with the material that comprises any covering layers disposed on the structure. An electric current pulse generator of the explosively driven magnetic flux compression type or variety may be advantageously used in the practice of this invention. 3 figs.

Weingart, R.C.

1988-04-27T23:59:59.000Z

20

Electrical method and apparatus for impelling the extruded ejection of high-velocity material jets  

DOE Patents (OSTI)

A method and apparatus (10, 40) for producing high-velocity material jets provided. An electric current pulse generator (14, 42) is attached to an end of a coaxial two-conductor transmission line (16, 44) having an outer cylindrical conductor (18), an inner cylindrical conductor (20), and a solid plastic or ceramic insulator (21) therebetween. A coxial, thin-walled metal structure (22, 30) is conductively joined to the two conductors (18, 20) of the transmission line (16, 44). An electrical current pulse applies magnetic pressure to and possibly explosively vaporizes metal structure (22), thereby collapsing it and impelling the extruded ejection of a high-velocity material jet therefrom. The jet is comprised of the metal of the structure (22), together with the material that comprises any covering layers (32, 34) disposed on the structure. An electric current pulse generator of the explosively driven magnetic flux compression type or variety (42) may be advantageously used in the practice of this invention.

Weingart, Richard C. (Livermore, CA)

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

WHAM Observations of H-alpha from High-Velocity Clouds Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H-alpha line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H-alpha emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

Tufte, S L; Madsen, G J; Haffner, L M; Reynolds, R J

2002-01-01T23:59:59.000Z

22

WHAM Observations of H-alpha from High-Velocity Clouds: Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H-alpha line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H-alpha emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

S. L. Tufte; J. D. Wilson; G. J. Madsen; L. M. Haffner; R. J. Reynolds

2002-06-12T23:59:59.000Z

23

The collisions of high-velocity clouds with the galactic halo  

E-Print Network (OSTI)

Spiral galaxies are surrounded by a widely distributed hot coronal gas and seem to be fed by infalling clouds of neutral hydrogen gas with low metallicity and high velocities. We numerically study plasma waves produced by the collisions of these high-velocity clouds (HVCs) with the hot halo gas and with the gaseous disk. In particular, we tackle two problems numerically: 1) collisions of HVCs with the galactic halo gas and 2) the dispersion relations to obtain the phase and group velocities of plasma waves from the equations of plasma motion as well as further important physical characteristics such as magnetic tension force, gas pressure, etc. The obtained results allow us to understand the nature of MHD waves produced during the collisions in galactic media and lead to the suggestion that these waves can heat the ambient halo gas. These calculations are aiming at leading to a better understanding of dynamics and interaction of HVCs with the galactic halo and of the importance of MHD waves as a heating proce...

Jelinek, Petr; 10.1016/j.cpc.2011.01.023

2011-01-01T23:59:59.000Z

24

The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars  

E-Print Network (OSTI)

Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for ~4700 K/M-giant stars in the Milky Way bulge. These high-resolution (R \\sim 22,500), high-S/N (>100 per resolution element), near-infrared (1.51-1.70 um; NIR) spectra provide accurate RVs (epsilon_v~0.2 km/s) for the sample of stars in 18 Galactic bulge fields spanning -1-32 deg. This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold (sigma_v~30 km/s), high-velocity peak (V_GSR \\sim +200 km/s) is found to comprise a significant fraction (~10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galac...

Nidever, David L; Majewski, Steven R; Bird, Jonathan; Robin, Annie C; Martinez-Valpuesta, Inma; Beaton, Rachael L; Schoenrich, Ralph; Schultheis, Mathias; Wilson, John C; Skrutskie, Michael F; O'Connell, Robert W; Shetrone, Matthew; Schiavon, Ricardo P; Johnson, Jennifer A; Weiner, Benjamin; Gerhard, Ortwin; Schneider, Donald P; Prieto, Carlos Allende; Sellgren, Kris; Bizyaev, Dmitry; Brewington, Howard; Brinkmann, Jon; Eisenstein, Daniel J; Frinchaboy, Peter M; Perez, Ana Elia Garcia; Holtzman, Jon; Hearty, Fred R; Malanushenko, Elena; Malanushenko, Viktor; Muna, Demitri; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie; Weaver, Benjamin A

2012-01-01T23:59:59.000Z

25

HIGH-RESOLUTION SEISMIC VELOCITY AND ATTENUATION MODELS OF THE CAUCASUS-CASPIAN REGION  

SciTech Connect

The southwest edge of Eurasia is a tectonically and structurally complex region that includes the Caspian and Black Sea basins, the Caucasus Mountains, and the high plateaus south of the Caucasus. Using data from 25 broadband stations located in the region, new estimates of crustal and upper mantle thickness, velocity structure, and attenuation are being developed. Receiver functions have been determined for all stations. Depth to Moho is estimated using slant stacking of the receiver functions, forward modeling, and inversion. Moho depths along the Caspian and in the Kura Depression are in general poorly constrained using only receiver functions due to thick sedimentary basin sediments. The best fitting models suggest a low velocity upper crust with Moho depths ranging from 30 to 40 km. Crustal thicknesses increase in the Greater Caucasus with Moho depths of 40 to 50 km. Pronounced variations with azimuth of source are observed indicating 3D structural complexity and upper crustal velocities are higher than in the Kura Depression to the south. In the Lesser Caucasus, south and west of the Kura Depression, the crust is thicker (40 to 50 km) and upper crustal velocities are higher. Work is underway to refine these models with the event based surface wave dispersion and ambient noise correlation measurements from continuous data. Regional phase (Lg and Pg) attenuation models as well as blockage maps for Pn and Sn are being developed. Two methods are used to estimate Q: the two-station method to estimate inter-station Q and the reversed, two-station, two event method. The results are then inverted to create Lg and Pg Q maps. Initial results suggest substantial variations in both Pg and Lg Q in the region. A zone of higher Pg Q extends west from the Caspian between the Lesser and Greater Caucasus and a narrow area of higher Lg Q is observed.

Mellors, R; Gok, R; Pasyanos, M; Skobeltsyn, G; Teoman, U; Godoladze, T; Sandvol, E

2008-07-01T23:59:59.000Z

26

EPRI Environmental Control Technology Center: FGD Wet Scrubber Performance At High Flue Gas Velocities  

Science Conference Proceedings (OSTI)

This report summarizes the impact of operating a wet flue gas desulfurization scrubber system at high flue gas velocities up to 20ft/sec (6.1 m/sec). It includes results for countercurrent spray, tray, and packing designs a variety of nozzle types. The report also describes the effect of adding dibasic acid and the impact of operation of state-of-the-art mist elimination systems. These results will be useful for planning compliance with SO2 emission regulations whether a new system is planned or addition...

1997-01-28T23:59:59.000Z

27

Galactic fountains and their connection with high and intermediate velocity clouds  

E-Print Network (OSTI)

The aim of this paper is to calculate the expansion law and chemical enrichment of a supershell powered by the energetic feedback of a typical Galactic OB association at various galactocentric radii. We study then the orbits of the fragments created when the supershell breaks out and we compare their kinetic and chemical properties with the available observations of high - and intermediate - velocity clouds. We use the Kompaneets (1960) approximation for the evolution of the superbubble driven by sequential supernova explosions and we compute the abundances of oxygen and iron residing in the thin cold supershell. We assume that supershells are fragmented by means of Rayleigh-Taylor instabilities and we follow the orbit of the clouds either ballistically or by means of a hybrid model considering viscous interaction between the clouds and the extra-planar gas.Given the self-similarity of the Kompaneets solutions, clouds are always formed ~ 448 pc above the plane. If the initial metallicity is solar, the pollution from dying stars of the OB association has a negligible effect on the chemical composition of the clouds. The maximum height reached by the clouds above the plane seldom exceeds 2 kpc and when averaging over different throwing angles, the landing coordinate differs from the throwing coordinate ~ 1 kpc at most. The range of heights and [O/Fe] ratios spun by our clouds suggest us that the high velocity clouds cannot have a Galactic origin, whereas intermediate velocity clouds have kinematic properties similar to our modeled clouds but overabundance observed for the [O/Fe] ratios which can be reproduced only with initial metallicities which are too low compared for those of the Galaxy disk.

E. Spitoni; S. Recchi; F. Matteucci

2008-03-20T23:59:59.000Z

28

High velocity continuous-flow reactor for the production of solar grade silicon. Second quarterly report  

DOE Green Energy (OSTI)

The objective is to determine the feasibility of a high volume-high velocity continuous reduction reactor as an economical means for producing solar grade polycrystalline silicon. Preheated streams of hydrogen and bromosilanes are used as feed to the reduction reactor. Nucleation and deposition sites are provided by the additional feed of preheated silicon particles to the reactor. The effort has been directed at studying the chemistry taking place in the reactor, determining the factors which influence its course, and making necessary reactor modifications as dictated by observed results. The initial reactor design has been extensively changed. Energy losses due to gas expansion in the nozzle/mixer section of the reactor dictated these design changes. A ''Tee'' configuration, in which the two preheated gas streams are merged at right angles without any expansion, has replaced the nozzle/mixer. Results of the hydrogen reduction of tetrabromosilane with and without the use of silicon deposition substrate particles are analyzed.

Woerner, L.

1978-03-01T23:59:59.000Z

29

Modelling and Simulation of Tensile Fracture in High Velocity Compacted Metal Powder  

Science Conference Proceedings (OSTI)

In cold uniaxial powder compaction, powder is formed into a desired shape with rigid tools and a die. After pressing, but before sintering, the compacted powder is called green body. A critical property in the metal powder pressing process is the mechanical properties of the green body. Beyond a green body free from defects, desired properties are high strength and uniform density. High velocity compaction (HVC) using a hydraulic operated hammer is a production method to form powder utilizing a shock wave. Pre-alloyed water atomised iron powder has been HVC-formed into circular discs with high densities. The diametral compression test also called the Brazilian disc test is an established method to measure tensile strength in low strength material like e.g. rock, concrete, polymers and ceramics. During the test a thin disc is compressed across the diameter to failure. The compression induces a tensile stress perpendicular to the compressed diameter. In this study the test have been used to study crack initiation and the tensile fracture process of HVC-formed metal powder discs with a relative density of 99%. A fictitious crack model controlled by a stress versus crack-width relationship is utilized to model green body cracking. Tensile strength is used as a failure condition and limits the stress in the fracture interface. The softening rate of the model is obtained from the corresponding rate of the dissipated energy. The deformation of the powder material is modelled with an elastic-plastic Cap model. The characteristics of the tensile fracture development of the central crack in a diametrically loaded specimen is numerically studied with a three dimensional finite element simulation. Results from the finite element simulation of the diametral compression test shows that it is possible to simulate fracturing of HVC-formed powder. Results from the simulation agree reasonably with experiments.

Jonsen, P.; Haeggblad, H.-A. [Division of Solid Mechanics, Department of Applied Physics and Mechanical Engineering, Luleaa University of Technology, 971 87 Luleaa (Sweden)

2007-05-17T23:59:59.000Z

30

Are Gamma Ray Bursts due to Rotation Powered High Velocity Pulsars in the Halo ?  

E-Print Network (OSTI)

The BATSE experiment has now observed more than 1100 gamma-ray bursts. The observed angular distribution is isotropic, while the brightness distribution of bursts shows a reduced number of faint events. These observations favor a cosmological burst origin. Alternatively, very extended Galactic Halo (EGH) models have been considered. In the latter scenario, the currently favored source of gamma-ray bursts involves high velocity pulsars ejected from the Galactic disk. To be compatible with the observed isotropy, most models invoke a sampling distance of 300 kpc, a turn-on delay of 30 Myrs, and a source life time of about 1 Gyr. We consider the global energy requirements of such models and show that the largest known resource. rotational kinetic energy, is insufficient by orders of magnitude to provide the observed burst rate. More exotic energy sources or differently tuned pulsar models may be able to get around the global energy constraint but at the cost of becoming contrived. Thus, while extended halo models are not ruled out, our arguments place a severe obstacle for such models and we encourage proponents of EGH models to clearly address the issue of global energetics.

Dieter Hartmann; Ramesh Narayan

1995-11-25T23:59:59.000Z

31

Probing Primordial and Pre-Galactic Lithium with High Velocity Clouds  

E-Print Network (OSTI)

The pre-Galactic abundance of lithium offers a unique window into non-thermal cosmological processes. The primordial Li abundance is guaranteed to be present and probes big bang nucleosynthesis (BBN), while an additional Li component is likely to have been produced by cosmic rays accelerated in large scale structure formation. Pre-Galactic Li currently can only be observed in low metallicity Galactic halo stars, but abundance measurements are plagued with systematic uncertainties due to modeling of stellar atmospheres and convection. We propose a new site for measuring pre-Galactic Li: low-metallicity, high-velocity clouds (HVCs) which are likely to be extragalactic gas accreted onto the Milky Way, and which already have been found to have deuterium abundances consistent with primordial. A Li observation in such an HVC would provide the first extragalactic Li measurement, and could shed new light on the apparent discrepancy between BBN predictions and halo star Li abundance determinations. Furthermore, HVC Li could at the same time test for the presence of non-primordial Li due to cosmic rays. The observability of elemental and isotopic Li abundances is discussed, and candidate sites identified.

Tijana Prodanovic; Brian D. Fields

2004-12-09T23:59:59.000Z

32

Measurement of a Magnetic Field in a Leading Arm High Velocity Cloud  

E-Print Network (OSTI)

Using a recent catalogue of extragalactic Faraday rotation derived from the NRAO VLA Sky Survey we have found an agreement between Faraday rotation structure and the HI emission structure of a High Velocity Cloud (HVC) associated with the Leading Arm of the Magellanic System. We suggest that this morphological agreement is indicative of Faraday rotation through the HVC. Under this assumption we have used 48 rotation measures through the HVC, together with estimates of the electron column density from H-\\alpha\\ measurements and QSO absorption lines to estimate a strength for the line-of-sight component of the coherent magnetic field in the HVC of > 6 {\\rm \\mu G}$. A coherent magnetic field of this strength is more than sufficient to dynamically stabilize the cloud against ram pressure stripping by the Milky Way halo and may also provide thermal insulation for the cold cloud. We estimate an upper limit to the ratio of random to coherent magnetic field of $B_{r}/B_{||} < 0.8$, which suggests that the random ...

McClure-Griffiths, N M; Gaensler, B M; McConnell, D; Schnitzeler, D H F M

2010-01-01T23:59:59.000Z

33

Doping-Dependent Nodal Fermi Velocity in Bi-2212 Revealed by High-Resolution ARPES  

Science Conference Proceedings (OSTI)

The improved resolution of laser-based angle-resolved photoemission spectroscopy (ARPES) allows reliable access to fine structures in the spectrum. We present a systematic, doping-dependent study of a recently discovered low-energy kink in the nodal dispersion of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-2212), which demonstrates the ubiquity and robustness of this kink in underdoped Bi-2212. The renormalization of the nodal velocity due to this kink becomes stronger with underdoping, revealing that the nodal Fermi velocity is non-universal, in contrast to assumed phenomenology. This is used together with laser-ARPES measurements of the gap velocity, v{sub 2}, to resolve discrepancies with thermal conductivity measurements.

Vishik, I. M.

2011-08-19T23:59:59.000Z

34

Probing High-Velocity Transient-Field Strength Using Heavy-ions Traversing Fe and Gd  

SciTech Connect

The transient field strength for {sup 76}Ge ions, passing through iron and gadolinium layers at velocities approxZv{sub 0}, has been measured. Although a sizeable value has been obtained for Gd, a vanishing strength has been observed in Fe.

Fiori, E.; Georgiev, G.; Cabaret, S.; Lozeva, R. [CSNSM, CNRS/IN2P3, Universite Paris-Sud 11, UMR8609, F-91405 ORSAY-Campus (France); Stuchbery, A. E. [Department of Nuclear Physics, Australian National University, Canberra (Australia); Jungclaus, A.; Modamio, V.; Walker, J. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain); Balabanski, D. L. [INRNE-BAS, Sofia (Bulgaria); Blazhev, A. [IKP, Cologne (Germany); Clement, E.; Grevy, S.; Stodel, C.; Thomas, J. C. [GANIL, Caen (France); Danchev, M. [University of Sofia (Bulgaria); Daugas, J. M. [CEA, DAM, DIF, 91297 Arpajon cedex (France); Hass, M.; Kumar, V. [The Weizmann Institute, Rehovot (Israel); Leske, J.; Pietralla, N. [TU Darmstadt, Darmstadt (Germany)

2009-08-26T23:59:59.000Z

35

On the X-ray low- and high-velocity outflows in AGNs  

E-Print Network (OSTI)

An exploration of the relationship between bolometric luminosity and outflow velocity, for two classes of X-ray outflows in a large sample of active galactic nuclei has been performed. We find that line radiation pressure could be one physical mechanism that might accelerate the gas we observe in warm absorber, v~100-1000 km/s, and on comparable but less stringent grounds the ultra-fast outflows (UFOs), v~0.03-0.3c. If comparable with the escape velocity of the system; the first is naturally located at distances of the dusty torus, ~ 1 pc, and the second at sub-parsec scales, ~ 0.01 pc, in accordance with large set of observational evidence existing in the literature. The presentation of this relationship might give us key clues for our understanding of the different physical mechanisms acting in the center of galaxies, the feedback process and its impact on the evolution of the host galaxy.

Ramirez, J M

2011-01-01T23:59:59.000Z

36

accepted to The Astrophysical Journal Letters WHAM Observations of H? from High Velocity Clouds: Are They Galactic or Extragalactic?  

E-Print Network (OSTI)

It has been suggested that high velocity clouds may be distributed throughout the Local Group and are therefore not in general associated with the Milky Way galaxy. With the aim of testing this hypothesis, we have made observations in the H? line of high velocity clouds selected as the most likely candidates for being at larger than average distances. We have found H? emission from 4 out of 5 of the observed clouds, suggesting that the clouds under study are being illuminated by a Lyman continuum flux greater than that of the metagalactic ionizing radiation. Therefore, it appears likely that these clouds are in the Galactic halo and not distributed throughout the Local Group.

S. L. Tufte; J. D. Wilson; G. J. Madsen; L. M. Haffner; R. J. Reynolds

2002-01-01T23:59:59.000Z

37

WHAM Observations of H-alpha Emission from High Velocity Clouds in the M, A, and C Complexes  

E-Print Network (OSTI)

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present results including clear detections of H-alpha emission from all three complexes with intensities ranging from 0.06 R to 0.20 R. In every observed direction where there is significant high velocity H I gas seen in the 21 cm line we have found associated ionized hydrogen emitting the H-alpha line. The velocities of the H-alpha and 21 cm emission are well correlated in every case except one, but the intensities are not correlated. There is some evidence that the ionized gas producing the H-alpha emission envelopes the 21 cm emitting neutral gas but the H-alpha "halo", if present, is not large. If the H-alpha emission arises from the photoionization of the H I clouds, then the implied Lyman continuum flux F_{LC} at the location of the clouds ranges from 1.3 to 4.2 x 10^5 photons cm^{-2} s^{-1}. If, on the other hand, the ionization is due to a shock arising from the collision of the high-velocity gas with an ambient medium in the halo, then the density of the pre-shocked gas can be constrained. We have also detected the [S II] 6716 angstrom line from the M I cloud and have evidence that the [S II] to H-alpha ratio varies with location on the cloud.

S. L. Tufte; R. J. Reynolds; L. M. Haffner

1998-07-15T23:59:59.000Z

38

WHAM Observations of H$\\alpha$ Emission from High Velocity Clouds in the M, A, and C Complexes  

E-Print Network (OSTI)

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present results including clear detections of H-alpha emission from all three complexes with intensities ranging from 0.06 R to 0.20 R. In every observed direction where there is significant high velocity H I gas seen in the 21 cm line we have found associated ionized hydrogen emitting the H-alpha line. The velocities of the H-alpha and 21 cm emission are well correlated in every case except one, but the intensities are not correlated. There is some evidence that the ionized gas producing the H-alpha emission envelopes the 21 cm emitting neutral gas but the H-alpha "halo", if present, is not large. If the H-alpha emission arises from the photoionization of the H I clouds, then the implied Lyman continuum flux F_{LC} at the location of the clouds ranges from 1.3 to 4.2 x 10^5 photons...

Tufte, S L; Haffner, L M

1998-01-01T23:59:59.000Z

39

THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT: FIRST DETECTION OF HIGH-VELOCITY MILKY WAY BAR STARS  

Science Conference Proceedings (OSTI)

Commissioning observations with the Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, have produced radial velocities (RVs) for {approx}4700 K/M-giant stars in the Milky Way (MW) bulge. These high-resolution (R {approx} 22, 500), high-S/N (>100 per resolution element), near-infrared (NIR; 1.51-1.70 {mu}m) spectra provide accurate RVs ({epsilon}{sub V} {approx} 0.2 km s{sup -1}) for the sample of stars in 18 Galactic bulge fields spanning -1 Degree-Sign -32 Degree-Sign . This represents the largest NIR high-resolution spectroscopic sample of giant stars ever assembled in this region of the Galaxy. A cold ({sigma}{sub V} {approx} 30 km s{sup -1}), high-velocity peak (V{sub GSR} Almost-Equal-To +200 km s{sup -1}) is found to comprise a significant fraction ({approx}10%) of stars in many of these fields. These high RVs have not been detected in previous MW surveys and are not expected for a simple, circularly rotating disk. Preliminary distance estimates rule out an origin from the background Sagittarius tidal stream or a new stream in the MW disk. Comparison to various Galactic models suggests that these high RVs are best explained by stars in orbits of the Galactic bar potential, although some observational features remain unexplained.

Nidever, David L.; Zasowski, Gail; Majewski, Steven R.; Beaton, Rachael L.; Wilson, John C.; Skrutskie, Michael F.; O'Connell, Robert W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Bird, Jonathan; Schoenrich, Ralph; Johnson, Jennifer A.; Sellgren, Kris [Department of Astronomy and the Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Robin, Annie C.; Schultheis, Mathias [Institut Utinam, CNRS UMR 6213, OSU THETA, Universite de Franche-Comte, 41bis avenue de l'Observatoire, F-25000 Besancon (France); Martinez-Valpuesta, Inma; Gerhard, Ortwin [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Shetrone, Matthew [McDonald Observatory, University of Texas at Austin, Fort Davis, TX 79734 (United States); Schiavon, Ricardo P. [Gemini Observatory, 670 North A'Ohoku Place, Hilo, HI 96720 (United States); Weiner, Benjamin [Steward Observatory, 933 North Cherry Street, University of Arizona, Tucson, AZ 85721 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Allende Prieto, Carlos, E-mail: dln5q@virginia.edu [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); and others

2012-08-20T23:59:59.000Z

40

Seismic Technology Adapted to Analyzing and Developing Geothermal Systems Below Surface-Exposed High-Velocity Rocks Final Report  

Science Conference Proceedings (OSTI)

The objective of our research was to develop and demonstrate seismic data-acquisition and data-processing technologies that allow geothermal prospects below high-velocity rock outcrops to be evaluated. To do this, we acquired a 3-component seismic test line across an area of exposed high-velocity rocks in Brewster County, Texas, where there is high heat flow and surface conditions mimic those found at numerous geothermal prospects. Seismic contractors have not succeeded in creating good-quality seismic data in this area for companies who have acquired data for oil and gas exploitation purposes. Our test profile traversed an area where high-velocity rocks and low-velocity sediment were exposed on the surface in alternating patterns that repeated along the test line. We verified that these surface conditions cause non-ending reverberations of Love waves, Rayleigh waves, and shallow critical refractions to travel across the earth surface between the boundaries of the fast-velocity and slow-velocity material exposed on the surface. These reverberating surface waves form the high level of noise in this area that does not allow reflections from deep interfaces to be seen and utilized. Our data-acquisition method of deploying a box array of closely spaced geophones allowed us to recognize and evaluate these surface-wave noise modes regardless of the azimuth direction to the surface anomaly that backscattered the waves and caused them to return to the test-line profile. With this knowledge of the surface-wave noise, we were able to process these test-line data to create P-P and SH-SH images that were superior to those produced by a skilled seismic data-processing contractor. Compared to the P-P data acquired along the test line, the SH-SH data provided a better detection of faults and could be used to trace these faults upward to the boundaries of exposed surface rocks. We expanded our comparison of the relative value of S-wave and P-wave seismic data for geothermal applications by inserting into this report a small part of the interpretation we have done with 3C3D data across Wister geothermal field in the Imperial Valley of California. This interpretation shows that P-SV data reveal faults (and by inference, also fractures) that cannot be easily, or confidently, seen with P-P data, and that the combination of P-P and P-SV data allows VP/VS velocity ratios to be estimated across a targeted reservoir interval to show where an interval has more sandstone (the preferred reservoir facies). The conclusion reached from this investigation is that S-wave seismic technology can be invaluable to geothermal operators. Thus we developed a strong interest in understanding the direct-S modes produced by vertical-force sources, particularly vertical vibrators, because if it can be demonstrated that direct-S modes produced by vertical-force sources can be used as effectively as the direct-S modes produced by horizontal-force sources, geothermal operators can acquire direct-S data across many more prospect areas than can be done with horizontal-force sources, which presently are limited to horizontal vibrators. We include some of our preliminary work in evaluating direct-S modes produced by vertical-force sources.

Hardage, Bob A; DeAngelo, Michael V; Ermolaeva, Elena; Hardage, Bob A; Remington, Randy; Sava, Diana; Wagner, Donald; Wei, Shuijion

2013-02-28T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

THE 21 cm 'OUTER ARM' AND THE OUTER-GALAXY HIGH-VELOCITY CLOUDS: CONNECTED BY KINEMATICS, METALLICITY, AND DISTANCE  

Science Conference Proceedings (OSTI)

Using high-resolution ultraviolet spectra obtained with the Hubble Space Telescope Space Telescope Imaging Spectrograph and the Far Ultraviolet Spectroscopic Explorer, we study the metallicity, kinematics, and distance of the gaseous 'outer arm' (OA) and the high-velocity clouds (HVCs) in the outer Galaxy. We detect the OA in a variety of absorption lines toward two QSOs, H1821+643 and HS0624+6907. We search for OA absorption toward eight Galactic stars and detect it in one case, which constrains the OA Galactocentric radius to 9 kpc absorption toward two stars; Complex G is therefore in the same region at R{sub G} = 8-10 kpc. HVC Complex C is known to be at a similar Galactocentric radius. Toward H1821+643, the low-ionization absorption lines are composed of multiple narrow components, indicating the presence of several cold clouds and rapid cooling and fragmentation. Some of the highly ionized gas is also surprisingly cool. Accounting for ionization corrections, we find that the OA metallicity is Z = 0.2-0.5 Z{sub Sun }, but nitrogen is underabundant and some species are possibly mildly depleted by dust. The similarity of the OA metallicity, Galactocentric location, and kinematics to those of the adjacent outer-Galaxy HVCs, including high velocities that are not consistent with Galactic rotation, suggests that the OA and outer-Galaxy HVCs could have a common origin.

Tripp, Todd M.; Song Limin, E-mail: tripp@astro.umass.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

2012-02-20T23:59:59.000Z

42

Evaluation of Fish-Injury Mechanisms During Exposure to a High-Velocity Jet  

DOE Green Energy (OSTI)

As part of the research supported by U.S. Department of Energy (DOE) Advanced Hydropower Turbine System (AHTS) Program, the Pacific Northwest National Laboratory (PNNL) conducted a study where age-0 and age-1 chinook salmon, as well as several other types of fish, were released into a submerged water jet to quantify injuries caused by shear stresses and turbulence (Neitzel et al. 2000). The fish releases were videotaped. These videotape records were digitized and analyzed using new methods to identify the injury mechanisms and the stresses involved. Visible external injuries sustained by fish in this study generally occurred during the initial contact with the jet and not during the tumbling that occurred after the fish fully entered the turbulent flow. The inertial stresses of tumbling, however, may cause temporary or even permanent vestibular and neurological injuries. Such injuries can result in disorientation and loss of equilibrium, which are life threatening in the ''natural'' environment. Operculum injuries predominated at moderate water jet speeds (12 and 15 m {center_dot} s{sup -1}). At the highest speed, eye, operculum, isthmus, and gill injuries were equally common, and disorientation was most common. Bruising and descaling were relatively rare, especially for age-0 fish. Age-0 fish were less susceptible than the larger age-1 fish to all visible injury types, especially at lower speeds. This is presumably because age-0 fish have less mass and inertia, and therefore sustain smaller forces on exposed organs during acceleration. Alternatively, age-0 fish were substantially more susceptible to behavioral impairments such as disorientation. This may also relate to the smaller mass of the age-0 fish. The less massive age-0 fish sustain larger accelerations and jerks, which may be important sources of the internal injuries to the vestibular and neurological systems. All the dynamic parameters computed from the bulk motion of the fish (velocity, jerk, and force) were positively correlated with injury level, based on the results of this study. Multinomial response model results further suggested that force is most predictive of injury.

Guensch, Greg R.; Mueller, Robert P.; McKinstry, Craig A.; Dauble, Dennis D.

2003-01-24T23:59:59.000Z

43

High Resolution Measurements of Turbulence, Velocity and Stress Using a Pulse-to-Pulse Coherent Sonar  

Science Conference Proceedings (OSTI)

Considered are the capabilities of a recently developed pulse-to-pulse coherent sonar called the High Resolution Current Profiler (HRCP). Special emphasis is placed on methods whereby reliable and accurate vertical profiles of turbulence ...

Atle Lohrmann; Bruce Hackett; Lars Petter Røed

1990-02-01T23:59:59.000Z

44

Program on Technology Innovation: Liquid Precursor High-Velocity Oxy-Fuel Spray Process for Making Fine Structured and Highly Bonded Alloy Coatings  

Science Conference Proceedings (OSTI)

High velocity oxygen-fuel (HVOF) thermal spray processes are used in applications requiring the highest density and adhesion strength, which is not achievable in most other thermal spray processes. Like other thermal spray processes, however, a normal HVOF process is not able to apply fine powders less than 10m via a conventional powder feeder like other thermal spray processes. The advantages of using smaller nano-sized particles in a HVOF process include uniform coating, uniform microstructure, higher ...

2007-03-28T23:59:59.000Z

45

Application of railgun principle to high-velocity hydrogen pellet injection for magnetic fusion reactor fueling  

DOE Green Energy (OSTI)

Three separate papers are included which report research progress during this period: (1) A new railgun configuration with perforated sidewalls, (2) development of a fuseless small-bore railgun for injection of high-speed hydrogen pellets into magnetically confined plasmas, and (3) controls and diagnostics on a fuseless railgun for solid hydrogen pellet injection.

Kim, K.; Zhang, J.

1992-01-01T23:59:59.000Z

46

Multi-point, high-speed passive ion velocity distribution diagnostic on the Pegasus Toroidal Experiment  

Science Conference Proceedings (OSTI)

A passive ion temperature polychromator has been deployed on Pegasus to study power balance and non-thermal ion distributions that arise during point source helicity injection. Spectra are recorded from a 1 m F/8.6 Czerny-Turner polychromator whose output is recorded by an intensified high-speed camera. The use of high orders allows for a dispersion of 0.02 A/mm in 4th order and a bandpass of 0.14 A ({approx}13 km/s) at 3131 A in 4th order with 100 {mu}m entrance slit. The instrument temperature of the spectrometer is 15 eV. Light from the output of an image intensifier in the spectrometer focal plane is coupled to a high-speed CMOS camera. The system can accommodate up to 20 spatial points recorded at 0.5 ms time resolution. During helicity injection, stochastic magnetic fields keep T{sub e} low ({approx}100 eV) and thus low ionization impurities penetrate to the core. Under these conditions, high core ion temperatures are measured (T{sub i} Almost-Equal-To 1.2 keV, T{sub e} Almost-Equal-To 0.1 keV) using spectral lines from carbon III, nitrogen III, and boron IV.

Burke, M. G.; Fonck, R. J.; Bongard, M. W.; Schlossberg, D. J.; Winz, G. R. [Department of Engineering Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States)

2012-10-15T23:59:59.000Z

47

Laser-based diagnostics for density, temperature, velocity, and dissociation fraction in high temperature hydrogen flows  

DOE Green Energy (OSTI)

This paper is essentially a review of the current state of the art in hydrogen atom and hydrogen molecule diagnostics. This paper contains some of our own results and ideas along with results from many other laboratories. This is not intended to be an exhaustive review; instead it summarizes some techniques which we believe are ideally suited as diagnostics for high temperature hydrogen which are of paramount importance for the Space Exploration Initiative (SEI). 31 refs., 1 fig.

Sappey, A.D.; Funk, D.J.

1991-01-01T23:59:59.000Z

48

The effect of load thickness on Rayleigh-Taylor mitigation in high velocity, annular z pinch implosion  

SciTech Connect

Numerical calculations have been performed to investigate the role that load thickness may play in the performance of fast annular z pinch implosions. In particular, the effects of load thickness on the mitigation of the magnetically-driven Rayleigh-Taylor (RT) instability and energy coupling between the load and generator are addressed. using parameters representative of the Z accelerator [R.B.Spielman et al., Phys.Plasmas, 5, 2105 (1998)] at Sandia National Laboratories, two dimensional magnetohydrodynamic (MHD) simulations show that increased shell thickness results in lower amplitude, slightly longer wavelength RT modes. In addition, there appears to be an optimum in load velocity which is directly associated with the thickness of the sheath and subsequent RT growth. Thin, annular loads, which should couple efficiently to the accelerator, show a large reduction in implosion velocity due to extreme RT development and increased load inductance. As a consequence, thicker loads on the order of 5 mm, couple almost as efficiently to the generator since the RT growth is reduced. This suggests that z-pinch loads can be tailored for different applications, depending on the need for uniformity or high powers.

DOUGLAS,MELISSA R.; DEENEY,CHRISTOPHER; RODERICK,NORMAN F.

2000-05-16T23:59:59.000Z

49

High velocity impact fracture  

E-Print Network (OSTI)

An in-depth understanding of dynamic ductile fracture is one of the most important steps to improve the survivability of critical structures such as the lost Twin Towers. In the present thesis, the macroscopic fracture ...

Teng, Xiaoqing

2005-01-01T23:59:59.000Z

50

The Far Ultraviolet Spectroscopic Explorer: Mission Overview and Prospects for Studies of the Interstellar Medium and High Velocity Clouds  

E-Print Network (OSTI)

The Far Ultraviolet Spectroscopic Explorer (FUSE) is a NASA astronomy mission that will explore the 905-1187 A wavelength region at high spectral resolution. Funded by NASA's Explorer Program, this Origins mission is scheduled for a 1999 launch and at least three years of operations. The development of FUSE is being led by the Johns Hopkins University, with major contributions to the program from the University of Colorado, the University of California-Berkeley, the space agencies of Canada and France, and corporate partners. FUSE will have approximately 10,000 times the sensitivity of its pioneering predecessor, Copernicus, which operated in the 1970s. Much of the FUSE Science Team observing time will be dedicated to studying the interstellar medium of the Milky Way and Magellanic Clouds. Observations of high velocity clouds play an important role in the FUSE program. In this paper, I outline some of the FUSE Science Team plans for observing HVCs. Simple absorption line models are also provided for investigators seeking to identify atomic and molecular species in this wavelength region.

Kenneth R. Sembach

1998-11-19T23:59:59.000Z

51

A compact single-camera system for high-speed, simultaneous 3-D velocity and temperature measurements.  

SciTech Connect

The University of Michigan and Sandia National Laboratories collaborated on the initial development of a compact single-camera approach for simultaneously measuring 3-D gasphase velocity and temperature fields at high frame rates. A compact diagnostic tool is desired to enable investigations of flows with limited optical access, such as near-wall flows in an internal combustion engine. These in-cylinder flows play a crucial role in improving engine performance. Thermographic phosphors were proposed as flow and temperature tracers to extend the capabilities of a novel, compact 3D velocimetry diagnostic to include high-speed thermometry. Ratiometric measurements were performed using two spectral bands of laser-induced phosphorescence emission from BaMg2Al10O17:Eu (BAM) phosphors in a heated air flow to determine the optimal optical configuration for accurate temperature measurements. The originally planned multi-year research project ended prematurely after the first year due to the Sandia-sponsored student leaving the research group at the University of Michigan.

Lu, Louise [University of Michigan, Ann Arbor, MI; Sick, Volker [University of Michigan, Ann Arbor, MI; Frank, Jonathan H.

2013-09-01T23:59:59.000Z

52

X-ray polarization spectroscopy to study anisotropic velocity distribution of hot electrons produced by an ultra-high-intensity laser  

SciTech Connect

The anisotropy of the hot-electron velocity distribution in ultra-high-intensity laser produced plasma was studied with x-ray polarization spectroscopy using multilayer planar targets including x-ray emission tracer in the middle layer. This measurement serves as a diagnostic for hot-electron transport from the laser-plasma interaction region to the overdense region where drastic changes in the isotropy of the electron velocity distribution are observed. These polarization degrees are consistent with analysis of a three-dimensional polarization spectroscopy model coupled with particle-in-cell simulations. Electron velocity distribution in the underdense region is affected by the electric field of the laser and that in the overdense region becomes wider with increase in the tracer depth. A full-angular spread in the overdense region of 22.4 deg.{sub -2.4}{sup +5.4} was obtained from the measured polarization degree.

Inubushi, Y. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Graduate School of Engineering, Osaka University, Suita, Osaka (Japan); Okano, Y.; Nishimura, H.; Cai, H.; Nagatomo, H.; Kai, T.; Fujioka, S.; Nakamura, T.; Johzaki, T.; Mima, K. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Kawamura, T. [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Batani, D.; Morace, A.; Redaelli, R. [Dipartmento di Fisica 'G. Occhialini', University of Milano-Bicocca, Milan (Italy); Fourment, C.; Santos, J. J.; Malka, G. [CELIA, Universite de Bordeaux/CNRS/CEA, Talence (France); Boscheron, A.; Bonville, O.; Grenier, J. [CEA/CESTA, Le Barp (France)

2010-03-15T23:59:59.000Z

53

Imaging Molecular Gas in the Luminous Merger NGC 3256 : Detection of High-Velocity Gas and Twin Gas Peaks in the Double Nucleus  

E-Print Network (OSTI)

Molecular gas in the merging starburst galaxy NGC 3256 has been imaged with the Submillimeter Array at a resolution of 1'' x 2'' (170 x 340 pc at 35 Mpc). This is the first interferometric imaging of molecular gas in the most luminous galaxy within z=0.01. There is a large disk of molecular gas (r > 3 kpc) in the center of the merger with a strong gas concentration toward the double nucleus. The gas disk having a mass of ~3*10^9 Msun in the central 3 kpc rotates around a point between the two nuclei that are 850 pc apart on the sky. The molecular gas is warm and turbulent and shows spatial variation of the intensity ratio between CO isotopomers. High-velocity molecular gas is discovered at the galactic center. Its velocity in our line of sight is up to 420 km/s offset from the systemic velocity of the galaxy; the terminal velocity is twice as large as that due to the rotation of the main gas disk. The high-velocity gas is most likely due to a molecular outflow from the gas disk, entrained by the starburst-driven superwind in the galaxy. The molecular outflow is estimated to have a rate of ~10 Msun/yr and to play a significant role in the dispersal or depletion of molecular gas from the galactic center. A compact gas concentration and steep velocity gradient are also found around each of the twin nuclei. They are suggestive of a small gas disk rotating around each nucleus. If these are indeed mini-disks, their dynamical masses are ~10^9 Msun within a radius of 170 pc.

Kazushi Sakamoto; Paul T. P. Ho; Alison B. Peck

2006-03-03T23:59:59.000Z

54

Detection of high-velocity material from the wind-wind collision zone of Eta Carinae across the 2009.0 periastron passage  

E-Print Network (OSTI)

We report near-IR spectroscopic observations of the Eta Carinae massive binary system during 2008-2009 using VLT/CRIRES. We detect a strong, broad absorption wing in He I 10833 extending up to -1900 km/s across the 2009.0 spectroscopic event. Archival HST/STIS ultraviolet and optical data shows a similar high-velocity absorption (up to -2100 km/s) in the UV resonance lines of Si IV 1394, 1403 across the 2003.5 event. UV lines from low-ionization species, such as Si II 1527, 1533 and C II 1334, 1335, show absorption up to -1200 km/s, indicating that the absorption with v from -1200 to -2100 km/s originates in a region markedly faster and more ionized than the nominal wind of the primary star. Observations obtained at the OPD/LNA during the last 4 spectroscopic cycles (1989-2009) also display high-velocity absorption in He I 10833 during periastron. Based on the OPD/LNA dataset, we determine that material with v 1.049. Therefore, we constrain the duration of the high-velocity absorption to be 95 to 206 days (o...

Groh, Jose H; Damineli, Augusto; Gull, Theodore R; Madura, Thomas I; Hillier, D J; Teodoro, Mairan; Driebe, Thomas; Weigelt, Gerd; Hartman, Henrik; Kerber, Florian; Okazaki, Atsuo T; Owocki, Stan P; Millour, Florentin; Murakawa, Koji; Kraus, Stefan; Hofmann, Karl-Heinz; Schertl, Dieter

2010-01-01T23:59:59.000Z

55

Experimental research of temperature and velocity fields in high-temperature flow of liquid heavy metal coolant  

Science Conference Proceedings (OSTI)

Presented are the results of experimental research of temperature and velocity fields for lead and lead-bismuth coolant flows in channels having circular and annular cross sections under varying oxygen content in the coolant and varying characteristics of insulating coatings. Tests are performed under the following operating conditions: (1) lead-bismuth eutectic-temperature T = 400-520 Degree-Sign C, thermodynamic oxygen activity a = 10{sup -5}-10{sup 0}, average flow velocity of the coolant w = 0.12-1.84 m/s, value of magnetic induction B = 0-0.85 T, Reynolds number Re = (0.24-3.5) Multiplication-Sign 10{sup 5}, Hartmann number Ha = 0-500, and Peclet number Pe = 320-4600; (2) lead coolant-T = 400-550 Degree-Sign C, a = 10{sup -5}-10{sup 0}, w = 0.1-1.5 m/s, Re = (2.36-2.99) Multiplication-Sign 10{sup 5}, and Pe = 500-7000.

Besnosov, A. V., E-mail: ats@nntu.nnov.ru; Savinov, S. Yu., E-mail: Savinov.S@mail.ru; Novozhilova, O. O.; Antonenkov, M. A. [Nizhni Novgorod State Technical University (Russian Federation)

2011-12-15T23:59:59.000Z

56

STELLAR VELOCITY DISPERSION MEASUREMENTS IN HIGH-LUMINOSITY QUASAR HOSTS AND IMPLICATIONS FOR THE AGN BLACK HOLE MASS SCALE  

SciTech Connect

We present new stellar velocity dispersion measurements for four luminous quasars with the Near-Infrared Integral Field Spectrometer instrument and the ALTAIR laser guide star adaptive optics system on the Gemini North 8 m telescope. Stellar velocity dispersion measurements and measurements of the supermassive black hole (BH) masses in luminous quasars are necessary to investigate the coevolution of BHs and galaxies, trace the details of accretion, and probe the nature of feedback. We find that higher-luminosity quasars with higher-mass BHs are not offset with respect to the M{sub BH}-{sigma}{sub *} relation exhibited by lower-luminosity active galactic nuclei (AGNs) with lower-mass BHs, nor do we see correlations with galaxy morphology. As part of this analysis, we have recalculated the virial products for the entire sample of reverberation-mapped AGNs and used these data to redetermine the mean virial factor (f) that places the reverberation data on the quiescent M{sub BH}-{sigma}{sub *} relation. With our updated measurements and new additions to the AGN sample, we obtain (f) = 4.31 {+-} 1.05, which is slightly lower than, but consistent with, most previous determinations.

Grier, C. J.; Martini, P.; Peterson, B. M.; Pogge, R. W.; Zu, Y. [Department of Astronomy, Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Watson, L. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Dasyra, K. M. [Observatoire de Paris, LERMA (CNRS:UMR8112), 61 Avenue de l'Observatoire, F-75014, Paris (France); Dietrich, M. [Department of Physics and Astronomy, Ohio University, Athens, OH 45601 (United States); Ferrarese, L. [Herzberg Institute of Astrophysics, National Research Council of Canada, 5071 West Saanich Road, Victoria BV V9E 2E7 (Canada)

2013-08-20T23:59:59.000Z

57

Development of a High Resolution X-Ray Imaging Crystal Spectrometer for Measurement of Ion-Temperature and Rotation-Velocity Profiles in Fusion Energy Research Plasmas  

SciTech Connect

A new imaging high resolution x-ray crystal spectrometer (XCS) has been developed to measure continuous profiles of ion temperature and rotation velocity in fusion plasmas. Following proof-of-principle tests on the Alcator C-Mod tokamak and the NSTX spherical tokamak, and successful testing of a new silicon, pixilated detector with 1MHz count rate capability per pixel, an imaging XCS is being designed to measure full profiles of Ti and v? on C-Mod. The imaging XCS design has also been adopted for ITER. Ion-temperature uncertainty and minimum measurable rotation velocity are calculated for the C-Mod spectrometer. The affects of x-ray and nuclear-radiation background on the measurement uncertainties are calculated to predict performance on ITER.

Hill, K W; Broennimann, Ch; Eikenberry, E F; Ince-Cushman, A; Lee, S G; Rice, J E; Scott, S

2008-02-27T23:59:59.000Z

58

The CRIRES Search for Planets Around the Lowest-Mass Stars. I. High-Precision Near-Infrared Radial Velocities with an Ammonia Gas Cell  

E-Print Network (OSTI)

Radial velocities measured from near-infrared spectra are a potentially powerful tool to search for planets around cool stars and sub-stellar objects. However, no technique currently exists that yields near-infrared radial velocity precision comparable to that which is routinely obtained in the visible. We describe a method for measuring high-precision relative radial velocities of cool stars from K-band spectra. The method makes use of a glass cell filled with ammonia gas to calibrate the spectrograph response similar to the iodine cell technique that has been used so successfully in the visible. Stellar spectra are obtained through the ammonia cell and modeled as the product of a Doppler-shifted template spectrum of the object and a spectrum of the cell, convolved with a variable instrumental profile model. A complicating factor is that a significant number of telluric absorption lines are present in the spectral regions containing useful stellar and ammonia lines. The telluric lines are modeled simultaneou...

Bean, Jacob L; Hartman, Henrik; Nilsson, Hampus; Wiedemann, Guenter; Reiners, Ansgar; Dreizler, Stefan; Henry, Todd J

2009-01-01T23:59:59.000Z

59

Velocity and Temperature Structure Functions in the Upper Troposphere and Lower Stratosphere from High-Resolution Aircraft Measurements  

Science Conference Proceedings (OSTI)

High-resolution measurements obtained from NOAA “best” atmospheric turbulence (BAT) probes mounted on an EGRETT high-altitude research aircraft were used to characterize turbulence in the upper troposphere and lower stratosphere at scales from 2 ...

Donald E. Wroblewski; Owen R. Coté; Jorg M. Hacker; Ronald J. Dobosy

2010-04-01T23:59:59.000Z

60

NEW GUN CAPABILITY WITH INTERCHANGABLE BARRELS TO INVESTIGATE LOW VELOCITY IMPACT REGIMES AT THE LAWRENCE LIVERMORE NATIONAL LABORATORY HIGH EXPLOSIVES APPLICATIONS FACILITY  

SciTech Connect

A new gas gun capability is being activated at Lawrence Livermore National Laboratories located in the High Explosives Applications Facility (HEAF). The single stage light gas (dry air, nitrogen, or helium) gun has interchangeable barrels ranging from 25.4 mm to 76.2 mm in diameter with 1.8 meters in length and is being fabricated by Physics Applications, Inc. Because it is being used for safety studies involving explosives, the gun is planned for operation inside a large enclosed firing tank, with typical velocities planned in the range of 10-300 m/s. Three applications planned for this gun include: low velocity impact of detonator or detonator/booster assemblies with various projectile shapes, the Steven Impact test that involves impact initiation of a cased explosive target, and the Taylor impact test using a cylindrical explosive sample impacted onto a rigid anvil for fracture studies of energetic materials. A highlight of the gun features, outline on work in progress for implementing this capability, and discussion of the planned areas of research will be included.

Vandersall, K S; Behn, A; Gresshoff, M; Jr., L F; Chiao, P I

2009-09-16T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

BONA FIDE, STRONG-VARIABLE GALACTIC LUMINOUS BLUE VARIABLE STARS ARE FAST ROTATORS: DETECTION OF A HIGH ROTATIONAL VELOCITY IN HR CARINAE  

Science Conference Proceedings (OSTI)

We report optical observations of the luminous blue variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to Si IV lambdalambda4088-4116. To match their observed line profiles from 2009 May, a high rotational velocity of v{sub rot} approx = 150 +- 20 km s{sup -1} is needed (assuming an inclination angle of 30 deg.), implying that HR Car rotates at approx =0.88 +- 0.2 of its critical velocity for breakup (v{sub crit}). Our results suggest that fast rotation is typical in all strong-variable, bona fide galactic LBVs, which present S-Dor-type variability. Strong-variable LBVs are located in a well-defined region of the HR diagram during visual minimum (the 'LBV minimum instability strip'). We suggest this region corresponds to where v{sub crit} is reached. To the left of this strip, a forbidden zone with v{sub rot}/v{sub crit}>1 is present, explaining why no LBVs are detected in this zone. Since dormant/ex LBVs like P Cygni and HD 168625 have low v{sub rot}, we propose that LBVs can be separated into two groups: fast-rotating, strong-variable stars showing S-Dor cycles (such as AG Car and HR Car) and slow-rotating stars with much less variability (such as P Cygni and HD 168625). We speculate that supernova (SN) progenitors which had S-Dor cycles before exploding (such as in SN 2001ig, SN 2003bg, and SN 2005gj) could have been fast rotators. We suggest that the potential difficulty of fast-rotating Galactic LBVs to lose angular momentum is additional evidence that such stars could explode during the LBV phase.

Groh, J. H. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Damineli, A.; Moises, A. P.; Teodoro, M. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, 05508-090, Sao Paulo, SP (Brazil); Hillier, D. J. [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260 (United States); Barba, R. [Departamento de fisica, Universidad de La Serena, Benavente 980, La Serena (Chile); Fernandez-Lajus, E.; Gamen, R. C.; Solivella, G., E-mail: jgroh@mpifr-bonn.mpg.d [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, and Instituto de Astrofisica de La Plata (CCT La Plata-CONICET), Paseo del Bosque S/N, B1900FWA, La Plata (Argentina)

2009-11-01T23:59:59.000Z

62

Unitaxial constant velocity microactuator  

SciTech Connect

A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment. The mechanism includes a flexible coupling having a bore therethrough, and two clamp/pusher assemblies mounted in axial ends of the coupling. The clamp/pusher assemblies are energized by voltage-operated piezoelectrics therewithin to operatively engage the shaft and coupling causing the shaft to move along its rotational axis through the bore. The microactuator is capable of repeatably positioning to sub-manometer accuracy while affording a scan range in excess of 5 centimeters. Moreover, the microactuator generates smooth, constant velocity motion profiles while producing a drive thrust of greater than 10 pounds. The system is remotely controlled and piezoelectrically driven, hence minimal thermal loading, vibrational excitation, or outgassing is introduced to the operating environment.

McIntyre, Timothy J. (Knoxville, TN)

1994-01-01T23:59:59.000Z

63

Fiber Optic Velocity Interferometry  

SciTech Connect

This paper explores the use of a new velocity measurement technique that has several advantages over existing techniques. It uses an optical fiber to carry coherent light to and from a moving target. A Fabry-Perot interferometer, formed by a gradient index lens and the moving target, produces fringes with a frequency proportional to the target velocity. This technique can measure velocities up to 10 km/s, is accurate, portable, and completely noninvasive.

Neyer, Barry T.

1988-04-01T23:59:59.000Z

64

ARM - Measurement - Vertical velocity  

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

govMeasurementsVertical velocity govMeasurementsVertical velocity ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Vertical velocity The component of the velocity vector, along the local vertical. Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments CO2FLX : Carbon Dioxide Flux Measurement Systems ECOR : Eddy Correlation Flux Measurement System KAZR : Ka ARM Zenith Radar MMCR : Millimeter Wavelength Cloud Radar SODAR : Mini Sound Detection and Ranging

65

Cirrus Crystal Terminal Velocities  

Science Conference Proceedings (OSTI)

Cirrus crystal terminal velocities are of primary importance in determining the rate of transport of condensate from upper- to middle-tropospheric levels and profoundly influence the earth’s radiation balance through their effect on the rate of ...

Andrew J. Heymsfield; Jean Iaquinta

2000-04-01T23:59:59.000Z

66

Vertical Velocity Focus Group  

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

Velocity Focus Group Velocity Focus Group ARM 2008 Science Team Meeting Norfolk, VA March 10-14 Background Vertical velocity measurements have been at the top of the priority list of the cloud modeling community for some time. Doppler measurements from ARM profiling radars operating at 915-MHz, 35-GHz and 94-GHz have been largely unexploited. The purpose of this new focus group is to develop vertical velocity ARM products suitable for modelers. ARM response to their request has been slow. Most ARM instruments are suitable for cloud observations and have limited capabilities in precipitation Using ARM datasets for evaluating and improving cloud parameterization in global climate models (GCMs) is not straightforward, due to gigantic scale mismatches. Consider this... Looking only vertically drastically limits opportunities

67

Diagnosing Mesoscale Vertical Motion from Horizontal Velocity and Density Data  

Science Conference Proceedings (OSTI)

The mesoscale vertical velocity is obtained by solving a generalized omega equation (? equation) using density and horizontal velocity data from three consecutive quasi-synoptic high-resolution surveys in the Alboran Sea. The Atlantic Jet (AJ) ...

Enric Pallàs Sanz; Álvaro Viúdez

2005-10-01T23:59:59.000Z

68

Perspectives on Deposition Velocity  

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

Deposition Deposition Velocity ... Going down the rabbit hole to explain that sinking feeling Brian DiNunno, Ph.D. Project Enhancement Corporation June 6 th , 2012 Discussion Framework ï‚— Development of the HSS Deposition Velocity Safety Bulletin ï‚— Broader discussion of appropriate conservatism within dispersion modeling and DOE-STD-3009 DOE-STD-3009 Dose Comparison "General discussion is provided for source term calculation and dose estimation, as well as prescriptive guidance for the latter. The intent is that calculations be based on reasonably conservative estimates of the various input parameters." - DOE-STD-3009, Appendix A.3 DOE-STD-3009 Dispersion

69

Velocity pump reaction turbine  

DOE Patents (OSTI)

An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

House, Palmer A. (Walnut Creek, CA)

1982-01-01T23:59:59.000Z

70

Velocity pump reaction turbine  

DOE Patents (OSTI)

An expanding hydraulic/two-phase velocity pump reaction turbine including a dual concentric rotor configuration with an inter-rotor annular flow channel in which the inner rotor is mechanically driven by the outer rotor. In another embodiment, the inner rotor is immobilized and provided with gas recovery ports on its outer surface by means of which gas in solution may be recovered. This velocity pump reaction turbine configuration is capable of potential energy conversion efficiencies of up to 70%, and is particularly suited for geothermal applications.

House, Palmer A. (Walnut Creek, CA)

1984-01-01T23:59:59.000Z

71

The velocity campaign for ignition on NIF  

SciTech Connect

Achieving inertial confinement fusion ignition requires a symmetric, high velocity implosion. Experiments show that we can reach 95 {+-} 5% of the required velocity by using a 420 TW, 1.6 MJ laser pulse. In addition, experiments with a depleted uranium hohlraum show an increase in capsule performance which suggests an additional 18 {+-} 5 {mu}m/ns of velocity with uranium hohlraums over gold hohlraums. Combining these two would give 99 {+-} 5% of the ignition velocity. Experiments show that we have the ability to tune symmetry using crossbeam transfer. We can control the second Legendre mode (P2) by changing the wavelength separation between the inner and outer cones of laser beams. We can control the azimuthal m = 4 asymmetry by changing the wavelength separation between the 23.5 and 30 degree beams on NIF. This paper describes our 'first pass' tuning the implosion velocity and shape on the National Ignition Facility laser [Moses et al., Phys. Plasmas, 16, 041006 (2009)].

Callahan, D. A.; Meezan, N. B.; Glenzer, S. H.; MacKinnon, A. J.; Benedetti, L. R.; Bradley, D. K.; Celeste, J. R.; Celliers, P. M.; Dixit, S. N.; Doeppner, T.; Dzentitis, E. G.; Glenn, S.; Haan, S. W.; Haynam, C. A.; Hicks, D. G.; Hinkel, D. E.; Jones, O. S.; Landen, O. L.; London, R. A.; MacPhee, A. G. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

2012-05-15T23:59:59.000Z

72

TEE-0010  

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

4, 2004 4, 2004 DECISION AND ORDER OFFICE OF HEARINGS AND APPEALS Applications for Exception Case Names: SpacePak Unico, Inc. Date of Filing: May 24, 2004 Case Numbers: TEE-0010 TEE-0011 This Decision and Order considers Applications for Exception filed by SpacePak and Unico, Inc. (Unico), seeking exception relief from the provisions of in C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). SpacePak and Unico are manufacturers of small duct, high velocity (SDHV) air conditioning equipment. In their exception requests, SpacePak and Unico assert that they will suffer a serious hardship and an unfair distribution of burdens if forced to comply with the 13 SEER energy efficiency standard effective January 2006, 10 C.F.R. § 430.32(c). If their Applications for Exception were

73

TEA-0008 - In the Matter of Unico, Inc. | Department of Energy  

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

08 - In the Matter of Unico, Inc. 08 - In the Matter of Unico, Inc. TEA-0008 - In the Matter of Unico, Inc. The present Appeal filed by Unico, Inc. (Unico), relates to a Decision and Order issued by the Office of Hearings and Appeals (OHA) on December 20, 2005, granting exception relief to Energy Savings Products, Ltd. (ESP) from the provisions of 10 C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). Energy Savings Products, Ltd., 29 DOE & 81,015 (2005) (ESP). ESP sought and obtained exception relief on the basis that the firm is a manufacturer of small duct, high velocity (SDHV) air conditioning equipment, and would suffer a gross inequity, serious hardship and an unfair distribution of burdens if forced to comply with

74

TEE-0026 - In the Matter of Energy Savings Products, Ltd. | Department of  

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

6 - In the Matter of Energy Savings Products, Ltd. 6 - In the Matter of Energy Savings Products, Ltd. TEE-0026 - In the Matter of Energy Savings Products, Ltd. This Decision and Order considers an Application for Exception filed by Energy Savings Products, Ltd. (ESP) seeking exception relief from the provisions of 10 C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). ESP is a manufacturer of small duct, high velocity (SDHV) air conditioning equipment. In its exception request, ESP asserts that the firm will suffer a gross inequity, serious hardship and an unfair distribution of burdens if forced to comply with the 13 SEER energy efficiency standard effective January 2006, 10 C.F.R. § 430.32(c). If its Application for Exception were granted, the

75

TEE-0011 - In the Matter of Unico, Inc. | Department of Energy  

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

1 - In the Matter of Unico, Inc. 1 - In the Matter of Unico, Inc. TEE-0011 - In the Matter of Unico, Inc. This Decision and Order considers Applications for Exception filed by SpacePak and Unico, Inc. (Unico), seeking exception relief from the provisions of in C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). SpacePak and Unico are manufacturers of small duct, high velocity (SDHV) air conditioning equipment. In their exception requests, SpacePak and Unico assert that they will suffer a serious hardship and an unfair distribution of burdens if forced to comply with the 13 SEER energy efficiency standard effective January 2006, 10 C.F.R. § 430.32(c). If their Applications for Exception were granted, the firms would receive exception relief from the revised

76

P:\DECISION\0026.tee.wpd  

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

, 2005 , 2005 DECISION AND ORDER OFFICE OF HEARINGS AND APPEALS Application for Exception Case Name: Energy Savings Products, Ltd. Date of Filing: September 28, 2005 Case Number: TEE-0026 This Decision and Order considers an Application for Exception filed by Energy Savings Products, Ltd. (ESP) seeking exception relief from the provisions of 10 C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). ESP is a manufacturer of small duct, high velocity (SDHV) air conditioning equipment. In its exception request, ESP asserts that the firm will suffer a gross inequity, serious hardship and an unfair distribution of burdens if forced to comply with the 13 SEER energy efficiency standard effective

77

Microsoft Word - 0008.tea.wpd  

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

June 30, 2006 June 30, 2006 DECISION AND ORDER OFFICE OF HEARINGS AND APPEALS Appeal Case Name: Unico, Inc. Date of Filing: January 19, 2006 Case Number: TEA-0008 The present Appeal filed by Unico, Inc. (Unico), relates to a Decision and Order issued by the Office of Hearings and Appeals (OHA) on December 20, 2005, granting exception relief to Energy Savings Products, Ltd. (ESP) from the provisions of 10 C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). Energy Savings Products, Ltd., 29 DOE & 81,015 (2005) (ESP). ESP sought and obtained exception relief on the basis that the firm is a manufacturer of small duct, high velocity (SDHV) air conditioning equipment, and would suffer a gross inequity,

78

TEE-0010 - In the Matter of SpacePak | Department of Energy  

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

0 - In the Matter of SpacePak 0 - In the Matter of SpacePak TEE-0010 - In the Matter of SpacePak This Decision and Order considers Applications for Exception filed by SpacePak and Unico, Inc. (Unico), seeking exception relief from the provisions of in C.F.R. Part 430, pertaining to energy conservation standards for central air conditioners and heat pumps (Air Conditioner Standards). SpacePak and Unico are manufacturers of small duct, high velocity (SDHV) air conditioning equipment. In their exception requests, SpacePak and Unico assert that they will suffer a serious hardship and an unfair distribution of burdens if forced to comply with the 13 SEER energy efficiency standard effective January 2006, 10 C.F.R. § 430.32(c). If their Applications for Exception were granted, the firms would receive exception relief from the revised

79

Chromospheric Doppler Velocity Oscillations in a Sunspot  

E-Print Network (OSTI)

We analyse the chromospheric Doppler velocity oscillations in a sunspot using the high resolution spectral observations obtained from the Fast Imaging Solar Spectrograph(FISS) of the New Solar Telescope at the Big Bear Solar Observatory. The Doppler velocity maps are constructed from the bisectors of the spectral observations. The time series analysis of Doppler velocity maps show enhanced power in the sunspot umbra at higher frequencies and in the penumbra at lower frequencies. We find that the peak power frequency decreases gradually from the umbra to outward.

Maurya, R A

2013-01-01T23:59:59.000Z

80

Application of railgun principle to high-velocity hydrogen pellet injection for magnetic fusion reactor fueling. Progress report, August 16, 1991--September 30, 1992  

DOE Green Energy (OSTI)

Three separate papers are included which report research progress during this period: (1) A new railgun configuration with perforated sidewalls, (2) development of a fuseless small-bore railgun for injection of high-speed hydrogen pellets into magnetically confined plasmas, and (3) controls and diagnostics on a fuseless railgun for solid hydrogen pellet injection.

Kim, K.; Zhang, J.

1992-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Impact of Hight Velocity Cold Spray Particles  

SciTech Connect

This paper presents experimental data and an computational model of the cold spray solid particle impact process. Copper particles impacting onto a polished stainless steel substrate are examined. The high velocity impact causes significant plastic deformation of both the particle and the sub- strate, but no melting is observed. The plastic deformation exposes clean surfaces that, under the high impact pressures, result in significant bond strengths between the particle and substrate. Experimental measurements of the splat and crater sizes compare well with the numerical calculations. It is shown that the crater depth is significant and increases with impact velocity. However, the splat diameter is much less sensitive to the impact velocity. It is also shown that the geometric lengths of the splat and crater scale linearly with the diameter of the impacting particle. It is hoped that the results presented will allow better understanding of the bonding process during cold spray.

Dykhuizen, R.C.; Gilmore, D.L.; Jiang, X.; Neiser, R.A.; Sampath, S.; Smith, M.F.

1998-12-01T23:59:59.000Z

82

VELOCITY INDICATOR FOR EXTRUSION PRESS  

DOE Patents (OSTI)

An indicator is presented for measuring the lowspeed velocity of an object in one direction where the object returns in the opposite direction at a high speed. The indicator comprises a drum having its axis of rotation transverse to the linear movement of the object and a tape wound upon the drum with its free end extending therefrom and adapted to be connected to the object. A constant torque is applied to the drum in a direction to wind the tape on the drum. The speed of the tape in the unwinding direction is indicated on a tachometer which is coupled through a shaft and clutch means to the drum only when the tape is unwinding.

Digney, F.J. Jr.; Bevilacqua, F.

1959-04-01T23:59:59.000Z

83

Fragmentation of multiply charged hydrocarbon molecules C{sub n}H{sup q+} (n{<=} 4, q{<=} 9) produced in high-velocity collisions: Branching ratios and kinetic energy release of the H{sup +} fragment  

Science Conference Proceedings (OSTI)

Fragmentation branching ratios for channels involving H{sup +} emission and associated kinetic energy release of the H{sup +} fragment [KER(H{sup +})] have been measured for multicharged C{sub n}H{sup q+} molecules produced in high velocity (3.6 a.u.) collisions between C{sub n}H{sup +} projectiles and helium atoms. For CH{sup q+} (q{=} 5), inner-shell ionization contributed in a prominent way to the ion production. In these two cases it was shown that measured KER(H{sup +}) were in good agreement with PCCM predictions when those were corrected for Auger relaxation with the same Auger lifetime value as in CH{sup 3+}.

Beroff, K.; Pino, T.; Carpentier, Y. [Institut des Sciences Moleculaires d'Orsay (ISMO), UMR CNRS 8214, Universite Paris Sud 11, bat.210, F-91405 Orsay Cedex (France); Van-Oanh, N. T. [Laboratoire de Chimie Physique (LCP), UMR CNRS 8000, Universite Paris Sud 11, Bat.349, F-91405 Orsay Cedex (France); Chabot, M.; Tuna, T.; Martinet, G. [Institut de Physique Nucleaire d'Orsay (IPNO), IN2P3- CNRS, Universite Paris Sud 11, F-91406 Orsay Cedex (France); Le Padellec, A. [Institut de Recherche en Astrophysique et Planetologie (IRAP), UMR CNRS 5187, Universite de Toulouse, 9 avenue du Colonel Roche, F-31028 Toulouse Cedex 9 (France); Lavergne, L. [Laboratoire de Physique Nucleaire et de Hautes Energies (LPNHE) UPMC, UPD, CNRS-IN2P3, 4 Place Jussieu, F-75005 Paris (France)

2011-09-15T23:59:59.000Z

84

Is there Lower Limit to Velocity or Velocity Change?  

E-Print Network (OSTI)

Here we explore the possibility of a lower limit to velocity or velocity change which is 20 orders of magnitude smaller than the speed of light and explore the various observable signatures including those in cosmic rays and gamma ray bursts.

B. N. Sreenath; Kenath Arun; C. Sivaram

2012-09-17T23:59:59.000Z

85

ARM - Measurement - Hydrometeor fall velocity  

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

fall velocity fall velocity ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Hydrometeor fall velocity Fall velocity of hydrometeors (e.g. rain, snow, graupel, hail). Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments DISDROMETER : Impact Disdrometer LDIS : Laser Disdrometer WSACR : Scanning ARM Cloud Radar, tuned to W-Band (95GHz) Field Campaign Instruments DISDROMETER : Impact Disdrometer PDI : Phase Doppler Interferometer

86

Vorticity from Line-of-Sight Lidar Velocity Scans  

Science Conference Proceedings (OSTI)

A method is presented to compute the spanwise vorticity in polar coordinates from 2D vertical cross sections of high-resolution line-of-sight Doppler wind lidar observations. The method uses the continuity equation to derive the velocity ...

Martin Weissmann; Andreas Dörnbrack; James D. Doyle

2009-12-01T23:59:59.000Z

87

A VAD-Based Dealiasing Method for Radar Velocity Data Quality Control  

Science Conference Proceedings (OSTI)

This paper describes a new velocity–azimuth display (VAD)-based dealiasing method developed for automated radar radial velocity data quality control to satisfy the high-quality standard and efficiency required by operational radar data ...

Qin Xu; Kang Nai; Li Wei; Pengfei Zhang; Shun Liu; David Parrish

2011-01-01T23:59:59.000Z

88

The Velocity-Selecting Cerenkov Counter  

E-Print Network (OSTI)

BAFFLE VELOCITY - SELECTING CERENKOV COUNTER (C 2) FiJI. 1velocity-selectinp: Cerenkov counter. ueaL-31;S CYLINDRICA~

Chamberlain, Owen; Weigand, Clyde

1956-01-01T23:59:59.000Z

89

Experimental Techniques for Measuring Temperature and Velocity...  

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

Measuring Temperature and Velocity Fields to Improve the Use and Validation of Building Heat Transfer Models Title Experimental Techniques for Measuring Temperature and Velocity...

90

Velocity Distributions from Nonextensive Thermodynamics  

E-Print Network (OSTI)

There is no accepted mechanism that explains the equilibrium structures that form in collisionless cosmological N-body simulations. Recent work has identified nonextensive thermodynamics as an innovative approach to the problem. The distribution function that results from adopting this framework has the same form as for polytropes, but the polytropic index is now related to the degree of nonextensiveness. In particular, the nonextensive approach can mimic the equilibrium structure of dark matter density profiles found in simulations. We extend the investigation of this approach to the velocity structures expected from nonextensive thermodynamics. We find that the nonextensive and simulated N-body rms-velocity distributions do not match one another. The nonextensive rms-velocity profile is either monotonically decreasing or displays little radial variation, each of which disagrees with the rms-velocity distributions seen in simulations. We conclude that the currently discussed nonextensive models require further modifications in order to corroborate dark matter halo simulations. (adapted from TeX)

Eric I. Barnes; Liliya L. R. Williams; Arif Babul; Julianne J. Dalcanton

2006-10-05T23:59:59.000Z

91

Forcing and Velocity Correlations in a Vibrated Granular Monolayer  

E-Print Network (OSTI)

The role of forcing on the dynamics of a vertically shaken granular monolayer is investigated. Using a flat plate, surprising negative velocity correlations are measured. A mechanism for this anti-correlation is proposed with support from both experimental results and molecular dynamics simulations. Using a rough plate, velocity correlations are positive, and the velocity distribution evolves from a gaussian at very low densities to a broader distribution at high densities. These results are interpreted as a balance between stochastic forcing, interparticle collisions, and friction with the plate.

Alexis Prevost; David A. Egolf; Jeffrey S. Urbach

2002-03-14T23:59:59.000Z

92

Particle Velocity and Deposition Efficiency in the Cold Spray Process  

SciTech Connect

Copper powder was sprayed by the cold-gas dynamic method. In-flight particle velocities were measured with a laser-two-focus system as a function of process parameters such as gas temperature, gas pressure, and powder feed rate. Particle velocities were uniform in a relatively large volume within the plume and agreed with theoretical predictions. The presence of the substrate was found to have no significant effect on particle velocities. Cold-spray deposition efficiencies were measured on aluminum substrates as a function of particle velocity and incident angle of the plume. Deposition efficiencies of up to 95% were achieved. The critical velocity for deposition was determined to be about 640 meters per second. This work investigates both the in-flight characteristics of copper particles in a supersonic cold-spray plume and the build-up of the subsequent coating on aluminum substrates. Velocities were found to be relatively constant within a large volume of the plume. Particle counts dropped off sharply away from the central axis. The presence of a substrate was found to have no effect on the velocity of the particles. A substantial mass-loading effect on the particle velocity was observed; particle velocities begin to drop as the mass ratio of powder to gas flow rates exceeds 3%. The measured variation of velocity with gas pressure and pre-heat temperature was in fairly good agreement with theoretical predictions. Helium may be used as the driving gas instead of air in order to achieve higher particle velocities for a given temperature and pressure. Coating deposition efficiencies were found to increase with particle velocity and decrease with gun- substrate angle. There did not appear to be any dependence of the deposition efficiency on coating thickness. A critical velocity for deposition of about 640 mk appears to fit the data well. The cold-spray technique shows promise as a method for the deposition of materials which are thermally sensitive or may experience rapid oxidation under typical thermal spray conditions. High deposition efficiencies are achievable for certain coating-substrate conditions. Work remains to determine the material and microstructural properties which govern the coating process.

Dykhuizen, R.C.; Gilmore, D.L.; Neiser, R.A.; Roemer, T.J.; Smith, M.F.

1998-11-12T23:59:59.000Z

93

DOE Workshop - Deposition Velocity Status  

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

Delivering DOE's Vision for the Delivering DOE's Vision for the East Tennessee Technology Park Mission Safely Delivering the Department of Energy's Vision for the East Tennessee Technology Park Mission DOE Workshop Deposition Velocity Status Mike Hitchler, Manager Nuclear Facility Safety June 5, 2012 Safely Delivering DOE's Vision for the East Tennessee Technology Park Mission Existing UCOR Analyses * UCOR facilities at East Tennessee Technology Park (ETTP) and Oak Ridge National Laboratory (ORNL) use various plume models depending on when they were developed and by whom. - Some use MACCS or MACCS2 for dispersion evaluation. (~5 locations) - LLLW uses ingestion modeling (multiple locations)

94

Property:Maximum Velocity(m/s) | Open Energy Information  

Open Energy Info (EERE)

Velocity(m/s) Velocity(m/s) Jump to: navigation, search Property Name Maximum Velocity(m/s) Property Type String Pages using the property "Maximum Velocity(m/s)" Showing 25 pages using this property. (previous 25) (next 25) A Alden Large Flume + 0.9 + B Bucknell Hydraulic Flume + 2.7 + C Carderock Maneuvering & Seakeeping Basin + 7.2 + Carderock Rotating Arm Tow Tank + 25.8 + Carderock Tow Tank 1 + 9.3 + Carderock Tow Tank 2 + 10.3 + Carderock Tow Tank 3 + 25.8 + Chase Tow Tank + 2.5 + D Davidson Laboratory Tow Tank + 18.3 + H Haynes Tow Tank + 1.8 + I Ice Towing Tank + 0.5 + L Lakefront Tow Tank + 2.7 + M MHL Free Surface Channel + 2 + MHL High Speed Cavitation + 25.9 + MHL Tow Tank + 6.7 + MIT Tow Tank + 1.5 + MMA Tugboat/ Barge/ Vessel + 5.1 + Maine Tow Tank + 3 +

95

Property:Velocity(m/s) | Open Energy Information  

Open Energy Info (EERE)

Velocity(m/s) Velocity(m/s) Jump to: navigation, search Property Name Velocity(m/s) Property Type String Pages using the property "Velocity(m/s)" Showing 21 pages using this property. A Alden Small Flume + >0.9 + B Bucknell Hydraulic Flume + 2.7 + C Carderock 2-ft Variable Pressure Cavitation Water Tunnel + 17 + Carderock 3-ft Variable Pressure Cavitation Water Tunnel + 25.8 + Carderock Circulating Water Channel + 5.2 + Carderock Large Cavitation Tunnel + 18 + Carderock Subsonic Wind Tunnel + 83.8 + D DeFrees Flume 1 + 2 + DeFrees Flume 2 + 2 + DeFrees Flume 3 + 2 + DeFrees Flume 4 + 2 + M MHL Free Surface Channel + 2 + MHL High Speed Cavitation + 25.9 + MHL Student Tunnel + 4.6 + P Penn Large Water Tunnel + 16.8 + Penn Small Water Tunnel + 21 + S SAFL Channel + 6.1 +

96

Universal Velocity-Field Characteristics for a Nanowire Arbitrary Degeneracy  

Science Conference Proceedings (OSTI)

The effects of electric field on the carrier motion and drift velocity in nanowire (NW) are presented in this paper. When the electric field is applied in NW, the electron is expected to move in anti-parallel direction to the electric field. This is so-called randomness motion is transformed into streamlined motion in extremely high electric field. The normalized Fermi energy and relative electron population as a function of electric field are examined for various degeneracies. It was found that the electric field has lesser influence on the relative electron population with the increased degeneracy. The drift velocity in NW is shown to increase with electric field until it reaches the saturation velocity. Two approximations have been made to simplify the theoretical equation. It is also shown in this paper that when the quantum emission is taken into account, the drift and saturation velocity degrades.

Chek, Desmond C. Y.; Hashim, Abdul Manaf [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Tan, Michael Loong Peng [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Arora, Vijay K. [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA 18766 (United States)

2011-05-25T23:59:59.000Z

97

Velocity Probability Density Functions for Oceanic Floats  

Science Conference Proceedings (OSTI)

Probability density functions (PDFs) of daily velocities from subsurface floats deployed in the North Atlantic and equatorial Atlantic Oceans are examined. In general, the PDFs are approximately Gaussian for small velocities, but with significant ...

Annalisa Bracco; J. H. LaCasce; Antonello Provenzale

2000-03-01T23:59:59.000Z

98

Equatorial Velocity Profiles. Part II: Zonal Component  

Science Conference Proceedings (OSTI)

Vertical profiles of horizontal velocity made along 53°E in the western Indian Ocean, during and after he onset of the southwest monsoon in 1976, show features in zonal velocity of relatively small vertical scale. Persistence of the features over ...

Kathleen O'Neill; James R. Luyten

1984-12-01T23:59:59.000Z

99

Determining Vertical Water Velocities from Seaglider  

Science Conference Proceedings (OSTI)

Vertical velocities in the world’s oceans are typically small, less than 1 cm s?1, posing a significant challenge for observational techniques. Seaglider, an autonomous profiling instrument, can be used to estimate vertical water velocity in the ...

Eleanor Frajka-Williams; Charles C. Eriksen; Peter B. Rhines; Ramsey R. Harcourt

2011-12-01T23:59:59.000Z

100

Velocity Probability Density Functions from Altimetry  

Science Conference Proceedings (OSTI)

Probability density functions (pdfs) are employed to evaluate the distribution of velocities in the global ocean. This study computes pdfs of ocean surface velocity using altimetric data from the TOPEX/Poseidon satellite. Results show that the ...

Sarah T. Gille; Stefan G. Llewellyn Smith

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Determining Velocities and Mixing Coefficients from Tracers  

Science Conference Proceedings (OSTI)

The effort to determine oceanic velocities from tracer distributions relies on a knowledge of the effects of mixing. However, the macroscopic diffusion coefficient, K, is generally not known and must be calculated along with the velocity. The ...

Jae Hak Lee; George Veronis

1989-04-01T23:59:59.000Z

102

An Acoustic Doppler and Electromagnetic Velocity Profiler  

Science Conference Proceedings (OSTI)

A freely failing current meter called the Absolute Velocity Profiler (AVP) is described. This profiler is an expansion of a previously developed instrument, the Electro-Magnetic Velocity Profiler (EMVP), with the additional capability of acoustic ...

Thomas B. Sanford; Robert G. Driver; John H. Dunlap

1985-06-01T23:59:59.000Z

103

Equatorial Velocity Profiles. Part I: Meridional Component  

Science Conference Proceedings (OSTI)

A time series or vertical profiles of horizontal velocity was collected in the western equatorial Indian Ocean during late spring of 1976. The meridional velocity component is examined here, the zonal component in Part II of this paper. The ...

Kathleen O'Neill

1984-12-01T23:59:59.000Z

104

Waterspout Velocity Measurements by Airborne Doppler Lidar  

Science Conference Proceedings (OSTI)

A Doppler lidar measures the line-of-sight velocity of cloud droplets in a waterspout much as a meteorological Doppler radar measures the velocity of larger hydrometeors. We discuss details of the application of an airborne Doppler lidar to ...

R. L. Schwiesow; R. E. Cupp; P. C. Sinclair; R. F. Abbey Jr.

1981-04-01T23:59:59.000Z

105

Influence of the inlet velocity profiles on the prediction of velocity distribution inside an electrostatic precipitator  

SciTech Connect

The influence of the velocity profile at the inlet boundary on the simulation of air velocity distribution inside an electrostatic precipitator is presented in this study. Measurements and simulations were performed in a duct and an electrostatic precipitator (ESP). A four-hole cobra probe was used for the measurement of velocity distribution. The flow simulation was performed by using the computational fluid dynamics (CFD) code FLUENT. Numerical calculations for the air flow were carried out by solving the Reynolds-averaged Navier-Stokes equations coupled with the realizable k-{epsilon} turbulence model equations. Simulations were performed with two different velocity profiles at the inlet boundary - one with a uniform (ideal) velocity profile and the other with a non-uniform (real) velocity profile to demonstrate the effect of velocity inlet boundary condition on the flow simulation results inside an ESP. The real velocity profile was obtained from the velocity measured at different points of the inlet boundary whereas the ideal velocity profile was obtained by calculating the mean value of the measured data. Simulation with the real velocity profile at the inlet boundary was found to predict better the velocity distribution inside the ESP suggesting that an experimentally measured velocity profile could be used as velocity inlet boundary condition for an accurate numerical simulation of the ESP. (author)

Haque, Shah M.E.; Deev, A.V.; Subaschandar, N. [Process Engineering and Light Metals (PELM) Centre, Faculty of Sciences, Engineering and Health, Central Queensland University, Gladstone, Queensland 4680 (Australia); Rasul, M.G.; Khan, M.M.K. [College of Engineering and Built Environment, Faculty of Sciences, Engineering and Health, Central Queensland University, Rockhampton, Queensland 4702 (Australia)

2009-01-15T23:59:59.000Z

106

Velocity of sound in the relic photon sea  

E-Print Network (OSTI)

We determine the velocity of sound in the blackbody gas of photons and in the gas of relic photons. Derivation is based on the thermodynamic theory of the photon gas and the Einstein relation between energy and mass. The spectral form for the n-dimensional blackbody is derived. The 1D, 2D and 3D blackbody radiation is specified. It is mentioned the possibility of creation of the Mach cone in case that the high energy cosmical particles moves with the speed greater than the velocity of sound in cosmical relic photon sea. Key words: Sound, elasticity, thermodynamics, blackbody, relic photons, Mach's cone.

Pardy, Miroslav

2013-01-01T23:59:59.000Z

107

Velocity of sound in the relic photon sea  

E-Print Network (OSTI)

We determine the velocity of sound in the blackbody gas of photons and in the gas of relic photons. Derivation is based on the thermodynamic theory of the photon gas and the Einstein relation between energy and mass. The spectral form for the n-dimensional blackbody is derived. The 1D, 2D and 3D blackbody radiation is specified. It is mentioned the possibility of creation of the Mach cone in case that the high energy cosmical particles moves with the speed greater than the velocity of sound in cosmical relic photon sea. Key words: Sound, elasticity, thermodynamics, blackbody, relic photons, Mach's cone.

Miroslav Pardy

2013-02-18T23:59:59.000Z

108

Impact Velocity (2011) | National Nuclear Security Administration  

National Nuclear Security Administration (NNSA)

Impact Velocity (2011) | National Nuclear Security Administration Impact Velocity (2011) | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > Media Room > Video Gallery > Impact Velocity (2011) Impact Velocity (2011) Impact Velocity (2011) From: NNSANews Views: 388 2 ratings Time: 02:26 More in Science & Technology See video Facebook Twitter

109

Estimation of Critical Flow Velocity for Collapse of Gas Test Loop Booster Fuel Assembly  

Science Conference Proceedings (OSTI)

This paper presents calculations performed to determine the critical flow velocity for plate collapse due to static instability for the Gas Test Loop booster fuel assembly. Long, slender plates arranged in a parallel configuration can experience static divergence and collapse at sufficiently high coolant flow rates. Such collapse was exhibited by the Oak Ridge High Flux Reactor in the 1940s and the Engineering Test Reactor at the Idaho National Laboratory in the 1950s. Theoretical formulas outlined by Miller, based upon wide-beam theory and Bernoulli’s equation, were used for the analysis. Calculations based upon Miller’s theory show that the actual coolant flow velocity is only 6% of the predicted critical flow velocity. Since there is a considerable margin between the theoretically predicted plate collapse velocity and the design velocity, the phenomena of plate collapse due to static instability is unlikely.

Guillen; Mark J. Russell

2006-07-01T23:59:59.000Z

110

Velocity and Attenuation Structure of the Geysers Geothermal Field, California  

DOE Green Energy (OSTI)

The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. The resource consists of primarily dry steam which is produced from a low, porosity fractured graywacke. Over the last several years steam pressure at the Geysers has been dropping. Concern over decline of the resource has prompted research to understand its fundamental nature. A key issue is the distribution of fluid in the matrix of the reservoir rock. In this paper we interpret seismic compressional-wave velocity and attenuation data at the Geysers in terms of the geologic structure and fluid saturation in the reservoir. Our data consist of approximately 300 earthquakes that are of magnitude 1.2 and are distributed in depth between sea level and 2.5 km. Using compressional-wave arrival times, we invert for earthquake location, origin time, and velocity along a three-dimensional grid. Using the initial pulse width of the compressional-wave, we invert for the initial pulse width associated with the source, and the one-dimensional Q structure. We find that the velocity structure correlates with known mapped geologic units, including a velocity high that is correlated with a felsite body at depth that is known from drilling. The dry steam reservoir, which is also known from drilling, is mostly correlated with low velocity. The Q increases with depth to the top of the dry steam reservoir and decreases with depth within the reservoir. The decrease of Q with depth probably indicates that the saturation of the matrix of the reservoir rock increases with depth.

Zucca, J. J.; Hutchings, L. J.; Kasameyer, P. W.

1993-01-01T23:59:59.000Z

111

What Should Be Considered When Simulating Doppler Velocities Measured by Ground-Based Weather Radars?  

Science Conference Proceedings (OSTI)

A sophisticated and flexible simulator of Doppler velocities measured by ground-based weather radars is appended to a high-resolution nonhydrostatic atmospheric model. Sensitivity experiments are conducted by using different configurations for ...

Olivier Caumont; Véronique Ducrocq

2008-08-01T23:59:59.000Z

112

Ensemble Kalman Filter Assimilation of Simulated HIWRAP Doppler Velocity Data in a Hurricane  

Science Conference Proceedings (OSTI)

This study utilizes ensemble Kalman filter (EnKF) observing system simulation experiments (OSSEs) to analyze the potential impact of assimilating radial velocity observations of hurricanes from the High-altitude Imaging Wind and Rain Airborne ...

Jason A. Sippel; Scott A. Braun; Fuqing Zhang; Yonghui Weng

2013-08-01T23:59:59.000Z

113

Potential Vorticity and Vertical Velocity at the Iceland-Færœs Front  

Science Conference Proceedings (OSTI)

Using data from high-resolution surveys of the Iceland- Færœs Front, the authors have calculated synoptic maps of the geostrophic velocity, vorticity, and potential vorticity on isopycnal surfaces. The data have also been used to diagnose the ...

J. T. Allen; D. A. Smeed

1996-12-01T23:59:59.000Z

114

Estimating Spatial Velocity Statistics with Coherent Doppler Lidar  

Science Conference Proceedings (OSTI)

The spatial statistics of a simulated turbulent velocity field are estimated using radial velocity estimates from simulated coherent Doppler lidar data. The structure functions from the radial velocity estimates are processed to estimate the ...

Rod Frehlich; Larry Cornman

2002-03-01T23:59:59.000Z

115

ARM - Evaluation Product - Convective Vertical Velocity  

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

ProductsConvective Vertical Velocity ProductsConvective Vertical Velocity Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Evaluation Product : Convective Vertical Velocity 2011.04.25 - 2011.05.23 Site(s) SGP General Description Convective processes play an important role in Earth's energy balance by distributing heat and moisture throughout the atmosphere. In particular, vertical air motions associated with these processes are inherently linked to the life cycle of these convective systems and are therefore directly tied to their energy budget. However, direct measurements of vertical air motions (e.g., in situ aircraft observations) are sparse, making it difficult to compare them with numerical model output, which relies on convective parameterization schemes that have yet to be extensively

116

Visibility graph analysis of solar wind velocity  

E-Print Network (OSTI)

We analyze in situ measurements of solar wind velocity obtained by Advanced Composition Explorer (ACE) spacecraft and Helios spacecraft during the years 1998-2012 and 1975-1983 respectively. The data belong to mainly solar cycle 23 (1996-2008) and solar cycle 21 (1976-1986) respectively. We use Directed Horizontal Visibility graph (DHVg) algorithm and estimate a graph functional, namely, the degree distance (D) as the Kullback-Leibler divergence (KLD) argument to understand time irreversibility of solar wind time series. We estimate this degree distance irreversibility parameter for these time series at different phases of solar activity cycle. Irreversibility parameter is first established for known dynamical data and then applied for solar wind velocity time series. It is observed that irreversibility in solar wind velocity fluctuations show similar behaviour at 0.3 AU (Helios data) and 1 AU (ACE data). Moreover it changes over the different phases of solar activity cycle.

Suyal, Vinita; Singh, Harinder P

2013-01-01T23:59:59.000Z

117

Modeling of Weld Penetration in High Velocity GTAW  

Science Conference Proceedings (OSTI)

... Boosted Suction (DDBS) System Doubles Pot Suction, Reduces Roof Emission ... Phase Change Materials in Thermal Energy Storage for Concentrating Solar ...

118

New Developments in High Velocity Air-fuel Spraying  

Science Conference Proceedings (OSTI)

This is possible because of the low temperature of air-fuel combustion. The heating of the spray ... Conditioning of Composite Lubricant Powder for Cold Spray.

119

Vehicle Velocity Estimation Based on RSS Measurements  

Science Conference Proceedings (OSTI)

This paper presents a technique which is based on pattern recognition techniques, in order to estimate Mobile Terminal (MT) velocity. The proposed technique applies on received signal strength (RSS) measurements and more precisely on information extracted ... Keywords: HIDden Markov Model, WCDMA, clustering, location based services, pattern recognition, propagation modeling, traffic information

Theodore S. Stamoulakatos; Antonis S. Markopoulos; Miltiadis E. Anagnostou; Michalis E. Theologou

2007-03-01T23:59:59.000Z

120

Aggregate Terminal Velocity/Temperature Relations  

Science Conference Proceedings (OSTI)

Terminal velocities of snow aggregates in storms along the Front Range in eastern Colorado are examined with a ground-based two-dimensional video disdrometer. Power-law relationships for particles having equivalent volume diameters of 0.5–20 mm ...

Edward A. Brandes; Kyoko Ikeda; Gregory Thompson; Michael Schönhuber

2008-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Experimental study of layer mixing, relative ionic escape velocity, and electron temperature gradients in spherical multilayered targets by XUV spectroscopy  

SciTech Connect

This past year we have undertaken experiments at the University of Rochester's Laboratory for Laser Energetics investigating layer mixing and expansion velocities of spherical targets uniformly irradiated by high intensity laser light. We performed high resolution spectroscopic measurements of spherical plasmas, produced using the Omega laser, and have observed enhanced broadening of XUV emission lines due to the expansion velocities.

Griem, H.R.

1990-07-01T23:59:59.000Z

122

Water Velocity Measurements on a Vertical Barrier Screen at the Bonneville Dam Second Powerhouse  

Science Conference Proceedings (OSTI)

Fish screens at hydroelectric dams help to protect rearing and migrating fish by preventing them from passing through the turbines and directing them towards the bypass channels by providing a sweeping flow parallel to the screen. However, fish screens may actually be harmful to fish if they become impinged on the surface of the screen or become disoriented due to poor flow conditions near the screen. Recent modifications to the vertical barrier screens (VBS) at the Bonneville Dam second powerhouse (B2) intended to increase the guidance of juvenile salmonids into the juvenile bypass system (JBS) have resulted in high mortality and descaling rates of hatchery subyearling Chinook salmon during the 2008 juvenile salmonid passage season. To investigate the potential cause of the high mortality and descaling rates, an in situ water velocity measurement study was conducted using acoustic Doppler velocimeters (ADV) in the gatewell slot at Units 12A and 14A of B2. From the measurements collected the average approach velocity, sweep velocity, and the root mean square (RMS) value of the velocity fluctuations were calculated. The approach velocities measured across the face of the VBS varied but were mostly less than 0.3 m/s. The sweep velocities also showed large variances across the face of the VBS with most measurements being less than 1.5 m/s. This study revealed that the approach velocities exceeded criteria recommended by NOAA Fisheries and Washington State Department of Fish and Wildlife intended to improve fish passage conditions.

Hughes, James S.; Deng, Zhiqun; Weiland, Mark A.; Martinez, Jayson J.; Yuan, Yong

2011-11-22T23:59:59.000Z

123

Effects of CO/sub 2/ flooding on wave velocities in rocks with hydrocarbons  

SciTech Connect

Compressional and shear-wave velocities were measured in the laboratory in seven sandstones (porosities ranging from 6 to 29%) and one unconsolidated sand (37% porosity) saturated with n-hexadecane (C/sub 16/H/sub 34/) both before and after CO/sub 2/ flooding. CO/sub 2/ flooding decreased compressional-wave velocities significantly, while shear-wave velocities were less affected. The magnitude of these effects was found to depend on confining and pore pressures, temperature, and porosities of the rocks. The experimental results and theoretical analysis show that the decreases in compressional-wave velocities caused by CO/sub 2/ flooding may be seismically resolvable in situ. Therefore, seismic--especially high-frequency, high-resolution seismic--methods may be useful in mapping and locating CO/sub 2/ zones, tracking movements of CO/sub 2/ fronts, and monitoring flooding processes in reservoirs undergoing CO/sub 2/ flooding.

Wang, Z. (Core Labs., Calgary (CA)); Nur, A.M. (Stanford Univ., Geophysics Dept., CA (US))

1989-11-01T23:59:59.000Z

124

Three-dimensional P and S waves velocity structures of the Coso geothermal  

Open Energy Info (EERE)

P and S waves velocity structures of the Coso geothermal P and S waves velocity structures of the Coso geothermal area, California, from microseismic travel time data Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Three-dimensional P and S waves velocity structures of the Coso geothermal area, California, from microseismic travel time data Details Activities (1) Areas (1) Regions (0) Abstract: High precision P and S wave travel times for 2104 microearthquakes with focus <6 km are used in a non-linear inversion to derive high-resolution three-dimensional compressional and shear velocity structures at the Coso Geothermal Area in eastern California. Block size for the inversion is 0.2 km horizontally and 0.5 km vertically and inversions are investigated in the upper 5 km of the geothermal area.

125

On the theory of turbulent flame velocity  

E-Print Network (OSTI)

The renormalization ideas of self-similar dynamics of a strongly turbulent flame front are applied to the case of a flame with realistically large thermal expansion of the burning matter. In that case a flame front is corrugated both by external turbulence and the intrinsic flame instability. The analytical formulas for the velocity of flame propagation are obtained. It is demonstrated that the flame instability is of principal importance when the integral turbulent length scale is much larger than the cut off wavelength of the instability. The developed theory is used to analyse recent experiments on turbulent flames propagating in tubes. It is demonstrated that most of the flame velocity increase measured experimentally is provided by the large scale effects like the flame instability, and not by the small-scale external turbulence.

Vitaly Bychkov; Vyacheslav Akkerman; Arkady Petchenko

2012-10-19T23:59:59.000Z

126

A new rf structure for intermediate-velocity particles  

Science Conference Proceedings (OSTI)

This paper describes an rf structure with high shunt impedance and good field stability for particle velocities o.1 {le} {beta} {le} 0.5. Traditionally, the drift-tube linac (DTL) has been the structure of choice for this velocity range. The new structure, called a coupled-cavity drift-tube linac (CCDTL), combines features of the Alvarez DTL and the {pi}-mode coupled-cavity linac (CCL). Each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between gaps is {gamma}{lambda}. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180{degrees}. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. We will discuss 2-D and 3-D electromagnetic code calculations, and some initial measurements on a low-power model of a CCDTL. We will compare shunt impedance calculations for DTL, CCL, and CCDTL structures. The CCDTL has potential application for a wide range of ion linacs. For example, high-intensity proton linacs could use the CCDTL instead of a DTL up to an energy of about 200 MeV. Another example is a stand-alone, low-duty, low-current, very high gradient, proton, cancer therapy machine. The advantage for this application would be a saving in the cost of the machine because the linac would be short.

Billen, J.H.; Krawczyk, F.L.; Wood, R.L.; Young, L.M.

1994-09-01T23:59:59.000Z

127

Drift velocity of electrons in quantum wells of selectively doped In{sub 0.5}Ga{sub 0.5}As/Al{sub x}In{sub 1-x}As and In{sub 0.2}Ga{sub 0.8}As/Al{sub x}Ga{sub 1-x}As heterostructures in high electric fields  

Science Conference Proceedings (OSTI)

The field dependence of drift velocity of electrons in quantum wells of selectively doped In{sub 0.5}Ga{sub 0.5}As/Al{sub x}In{sub 1-x}As and In{sub 0.2}Ga{sub 0.8}As/Al{sub x}Ga{sub 1-x}As heterostructures is calculated by the Monte Carlo method. The influence of varying the molar fraction of Al in the composition of the Al{sub x}Ga{sub 1-x}As and Al{sub x}In{sub 1-x}As barriers of the quantum well on the mobility and drift velocity of electrons in high electric fields is studied. It is shown that the electron mobility rises as the fraction x of Al in the barrier composition is decreased. The maximum mobility in the In{sub 0.5}Ga{sub 0.5}As/In{sub 0.8}Al{sub 0.2}As quantum wells exceeds the mobility in a bulk material by a factor of 3. An increase in fraction x of Al in the barrier leads to an increase in the threshold field E{sub th} of intervalley transfer (the Gunn effect). The threshold field is E{sub th} = 16 kV/cm in the In{sub 0.5}Ga{sub 0.5}As/Al{sub 0.5}In{sub 0.5}As heterostructures and E{sub th} = 10 kV/cm in the In{sub 0.2}Ga{sub 0.8}As/Al{sub 0.3}Ga{sub 0.7}As heterostructures. In the heterostructures with the lowest electron mobility, E{sub th} = 2-3 kV/cm, which is lower than E{sub th} = 4 kV/cm in bulk InGaAs.

Pozela, J., E-mail: pozela@pfi.lt; Pozela, K.; Raguotis, R.; Juciene, V. [Center for Physical Sciences and Technology, Semiconductor Physics Institute (Lithuania)

2011-06-15T23:59:59.000Z

128

Unexplored Aspect of Velocity of light  

E-Print Network (OSTI)

In the post-Maxwellian era, sensing that the tide of discoveries in electromagnetim indicated a decline of the mechanical view, Einstein replaced Newton's three absolutes -- space, time and mass, with a single one, the velocity of light. The magnitude of the velocity of light was first determined and proven to be finite independently by Ole Romer and Bradley in the eighteenth century. In the nineteenth century, Fizeau carried out the first successful measurement of the speed of light using an earthbound apparatus. Thereafter, many earthbound experiments were conducted for its determination till 1983, when its magnitude was frozen at a fixed value after it was determined up to an accuracy level of a fraction of a meter per second. Einstein considered the speed of light derived from terrestrial experiments, to be the limiting speed of all natural phenomena. Einstein stated in connection with his general relativity theory that light rays could curve only when the velocity of propagation of light varies with position. Experiments have been conducted to prove the phenomenon of light deflection to higher and higher accuracy levels, but none so far to determine the speed of light at locations closer to the sun. To verify some essential aspects of general relativity, NASA had commendably planned many costly experiments. Hence, NASA can now be expected to expeditiously plan and execute the low cost experiment proposed here, so as to conclusively verify the effect of the solar gravitational field on the speed of light, as regards the important predictions of Einstein's theory of gravitation and of its remodeled form -- the Remodeled Relativity Theory, which retained and incorporated only experimentally proven concepts and principles.

Abhijit Biswas; Krishnan RS Mani

2008-05-13T23:59:59.000Z

129

Laser Doppler Velocimeter particle velocity measurement system  

DOE Green Energy (OSTI)

This report gives a detailed description of the operation of the Laser Doppler Velocimeter (LDV) system maintained by DIAL at MSU. LDV is used for the measurement of flow velocities and turbulence levels in various fluid flow settings. Ills report details the operation and maintenance of the LDV system and provides a first-time user with pertinent information regarding the system`s setup for a particular application. Particular attention has been given to the use of the Doppler signal analyzer (DSA) and the burst spectrum analyzer (BSA) signal processors and data analysis.

Wilson, W.W.; Srikantaiah, D.V.; Philip, T.; George, A.

1993-10-01T23:59:59.000Z

130

HALO VELOCITY GROUPS IN THE PISCES OVERDENSITY  

Science Conference Proceedings (OSTI)

We report spectroscopic observations of five faint (V {approx} 20) RR Lyrae stars associated with the Pisces overdensity conducted with the Gemini South Telescope. At a heliocentric and galactocentric distance of {approx}80 kpc, this is the most distant substructure in the Galactic halo known to date. We combined our observations with literature data and confirmed that the substructure is composed of two different kinematic groups. The main group contains eight stars and has (V{sub gsr}) = 50 km s{sup -1}, while the second group contains four stars at a velocity of (V{sub gsr}) = -52 km s{sup -1}, where V{sub gsr} is the radial velocity in the galactocentric standard of rest. The metallicity distribution of RR Lyrae stars in the Pisces overdensity is centered on [Fe/H] = -1.5 dex and has a width of 0.3 dex. The new data allowed us to establish that both groups are spatially extended making it very unlikely that they are bound systems, and are more likely to be debris of a tidally disrupted galaxy or galaxies. Due to small sky coverage, it is still unclear whether these groups have the same or different progenitors.

Sesar, Branimir; Ivezic, Zeljko [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195-1580 (United States); Vivas, A. Katherina [Centro de Investigaciones de Astronomia (CIDA), Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of); Duffau, Sonia, E-mail: bsesar@u.washington.ed, E-mail: zi@u.washington.ed, E-mail: akvivas@cida.v, E-mail: sonia.duffau@gmail.co [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Moenchhofstrasse 12-14, D-69120 Heidelberg (Germany)

2010-07-01T23:59:59.000Z

131

Radar Wind Profiler Radial Velocity: A Comparison with Doppler Lidar  

Science Conference Proceedings (OSTI)

The accuracy of the radial wind velocity measured with a radar wind profiler will depend on turbulent variability and instrumental noise. Radial velocity estimates of a boundary layer wind profiler are compared with those estimated by a Doppler ...

Stephen A. Cohn; R. Kent Goodrich

2002-12-01T23:59:59.000Z

132

The Accuracy of Vertical Air Velocities from Doppler Radar Data  

Science Conference Proceedings (OSTI)

Eight methods of calculating vertical air velocity in a column are compared. Each method requires some or all of the following data: horizontal divergence, vertical precipitation velocity, hydrometeor terminal fall speed, and vertical air ...

Thomas Matejka; Diana L. Bartels

1998-01-01T23:59:59.000Z

133

Terminal Velocity Adjustments for Plate-like Crystals and Graupel  

Science Conference Proceedings (OSTI)

Velocity adjustments are evaluated for altitude changes using Reynolds number-Davies number correlations of the form Re = aXb which have been obtained from empirical fall velocities of ice particles. In general, the altitude adjustment was found ...

Kenneth V. Beard; Andrew J. Heymsfield

1988-11-01T23:59:59.000Z

134

LAMINAR BURNING VELOCITY OF GASOLINES WITH ADDITION OF ETHANOL  

E-Print Network (OSTI)

1 LAMINAR BURNING VELOCITY OF GASOLINES WITH ADDITION OF ETHANOL P. Dirrenberger1 , P.A. Glaude*1 (2014) 162-169" DOI : 10.1016/j.fuel.2013.07.015 #12;2 LAMINAR BURNING VELOCITY OF GASOLINES, Sweden Abstract The adiabatic laminar burning velocities of a commercial gasoline and of a model fuel (n

135

Observations of Velocity Conditions near a Hydroelectric Turbine Draft Tube Exit using ADCP Measurements  

Science Conference Proceedings (OSTI)

Measurement of flow characteristics near hydraulic structures is an ongoing challenge because of the need to obtain rapid measurements of time-varying velocity over a relatively large spatial domain. This paper discusses use of an acoustic Doppler current profiler (ADCP) to measure the rapidly diverging flow exiting from an operating hydroelectric turbine draft tube exit. The resolved three-dimensional velocity vectors show a highly complex and helical flow pattern developed near to and downstream of the exit. Velocity vectors were integrated across the exit and we computed an uneven percentage of flow (67%/33%) passing through the two draft tube barrels at a mid-range turbine discharge, consistent with physical model results. In addition to the three-dimensional velocity vectors, the individual one-dimensional velocities measured by each of the four ADCP beams can be separately used as calibration and validation datasets for numerical and physical models. This technique is demonstrated by comparing along-beam ADCP velocity measurements to data collected in a scaled physical model.

Cook, Christopher B.; Richmond, Marshall C.; Serkowski, John A.

2007-10-01T23:59:59.000Z

136

Force-velocity relations for multiple-molecular-motor transport  

E-Print Network (OSTI)

A transition rate model of cargo transport by $N$ molecular motors is proposed. Under the assumption of steady state, the force-velocity curve of multi-motor system can be derived from the force-velocity curve of single motor. Our work shows, in the case of low load, the velocity of multi-motor system can decrease or increase with increasing motor number, which is dependent on the single motor force-velocity curve. And most commonly, the velocity decreases. This gives a possible explanation to some recent

Ziqing Wang; Ming Li

2009-06-26T23:59:59.000Z

137

Three-dimensional p-velocity structure of the summit caldera of Newberry Volcano, Oregon  

DOE Green Energy (OSTI)

A three-dimensional high-resolution seismic study of the summit caldera of Newberry Volcano, Oregon, was conducted by the US Geological Survey using an adaptation of the method applied by Mercessian et al. (1984). Preliminary interpretation of the traveltime residuals reveals a ring of high P-velocity material coinciding with the inner ring fault system of the caldera in the upper 2 km. A zone of lower P velocities extends deeper than 2 km in the center of the caldera. 9 refs., 5 figs.

Stauber, D.A.; Iyer, N.M.; Mooney, W.D.; Dawson, P.B.

1985-01-01T23:59:59.000Z

138

Laminar burning velocities and flame instabilities of butanol isomers-air mixtures  

SciTech Connect

Laminar burning velocities and flame instabilities of the butanol-air premixed flames and its isomers are investigated using the spherically expanding flame with central ignition at initial temperature of 428 K and initial pressures of 0.10 MPa, 0.25 MPa, 0.50 MPa and 0.75 MPa. Laminar burning velocities and sensitivity factor of n-butanol-air mixtures are computed using a newly developed kinetic mechanism. Unstretched laminar burning velocity, adiabatic temperature, Lewis number, Markstein length, critical flame radius and Peclet number are obtained over a wide range of equivalence ratios. Effect of molecular structure on laminar burning velocity of the isomers of butanol is analyzed from the aspect of C-H bond dissociation energy. Study indicates that although adiabatic flame temperatures of the isomers of butanol are the same, laminar burning velocities give an obvious difference among the isomers of butanol. This indicates that molecular structure has a large influence on laminar burning velocities of the isomers of butanol. Branching (-CH3) will decrease laminar burning velocity. Hydroxyl functional group (-OH) attaching to the terminal carbon atoms gives higher laminar burning velocity compared to that attaching to the inner carbon atoms. Calculated dissociation bond energies show that terminal C-H bonds have larger bond energies than that of inner C-H bonds. n-Butanol, no branching and with hydroxyl functional group (-OH) attaching to the terminal carbon atom, gives the largest laminar burning velocity. tert-Butanol, with highly branching and hydroxyl functional group (-OH) attaching to the inner carbon atom, gives the lowest laminar burning velocity. Laminar burning velocities of iso-butanol and sec-butanol are between those of n-butanol and tert-butanol. The instant of transition to cellularity is experimentally determined for the isomers of butanol and subsequently interpreted on the basis of hydrodynamic and diffusion-thermal instabilities. Little effect on flame instability is observed for the isomers of butanol. Critical flame radii are the same for the isomers of butanol. Peclet number decreases with the increase in equivalence ratio. (author)

Gu, Xiaolei; Huang, Zuohua; Wu, Si; Li, Qianqian [State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)

2010-12-15T23:59:59.000Z

139

Turbulent Velocity-Variance Profiles in the Stable Boundary Layer Generated by a Nocturnal Low-Level Jet  

Science Conference Proceedings (OSTI)

Profiles of mean winds and turbulence were measured by the High Resolution Doppler lidar in the strong-wind stable boundary layer (SBL) with continuous turbulence. The turbulence quantity measured was the variance of the streamwise wind velocity ...

Robert M. Banta; Yelena L. Pichugina; W. Alan Brewer

2006-11-01T23:59:59.000Z

140

high  

Gasoline and Diesel Fuel Update (EIA)

0 0 Summary Our short-term outlook for a wide array of energy prices has been adjusted upward as international and domestic energy supply conditions have tightened. We think that crude oil prices are as likely as not to end the year $2 to $3 per barrel higher than our previous projections. Thus, we think that the probability of West Texas Intermediate costing an average of $30 per barrel or more at midwinter is about 50 percent. On their current track, heating oil prices are likely to be about 30 percent above year-ago levels in the fourth quarter. Prices for Q1 2001 seem more likely now to match or exceed the high level seen in Q1 2000. Tight oil markets this year and an inherent propensity for high gas utilization in incremental power supply have resulted in rising North American natural gas

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141

Initial Examination of Low Velocity Sphere Impact of Glass Ceramics  

SciTech Connect

This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (< 30 m/s or < 65 mph) sphere impact testing of two materials from the lithium aluminosilicate family reinforced with different amounts of ceramic particulate, i.e., glass-ceramic materials, SCHOTT Resistan{trademark}-G1 and SCHOTT Resistan{trademark}-L. Both materials are provided by SCHOTT Glass (Duryea, PA). This work is a follow-up to similar sphere impact studies completed by the authors on PPG's Starphire{reg_sign} soda-lime silicate glass and SCHOTT BOROFLOAT{reg_sign} borosilicate glass. A gas gun or a sphere-drop test setup was used to produce controlled velocity delivery of silicon nitride (Si{sub 3}N{sub 4}) spheres against the glass ceramic tile targets. Minimum impact velocities to initiate fracture in the glass-ceramics were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between sphere and target material. Quasistatic spherical indentation was also performed on both glass ceramics and their contact damage responses were compared to those of soda-lime silicate and borosilicate glasses. Lastly, variability of contact damage response was assessed by performing spherical indentation testing across the area of an entire glass ceramic tile. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Resistan{trademark}-L glass ceramic required the highest velocity of sphere impact for damage to initiate. Starphire{reg_sign} soda-lime silicate glass was second best, then Resistan{trademark}-G1 glass ceramic, and then BOROFLOAT{reg_sign} borosilicate glass. (2) Glass-ceramic Resistan{trademark}-L also required the largest force to initiate ring crack from quasi-static indentation. That ranking was followed, in descending order, by Starphire{reg_sign} soda-lime silicate glass, Resistan{trademark}-G1 glass ceramic, and BOROFLOAT{reg_sign} borosilicate glass. (3) Spheres with a lower elastic modulus require less force to initiate fracture in Resistan{trademark}-G1 from quasi-static spherical indentation. This indicates that friction is affecting ring crack initiation in Resistan{trademark}-G1. Friction also affected ring crack initiation in Starphire{reg_sign} soda-lime silicate and BOROFLOAT{reg_sign} borosilicate glasses. Among these three materials, friction was the most pronounced (largest slope in the RCIF-elastic modulus graph) in the Starphire{reg_sign} and least pronounced in the BOROFLOAT{reg_sign}. The reason for this is not understood, but differences in deformation behavior under high contact stresses could be a cause or contributor to this. (4) The force necessary to initiate contact-induced fracture is higher under dynamic conditions than it is under quasi-static conditions in Resistan{trademark}-L and Resistan{trademark}-G1 glass ceramics. This is a trend observed too in Starphire{reg_sign} and BOROFLOAT{reg_sign}. (5) There is a subtle indication there was intra-tile differences in spherical indentation-induced ring crack initiation forces. This is not a material property nor is it exclusive to glass-ceramic Resistan{trademark}-G1 glass ceramic, rather, it is a statistical mechanical response to an accumulated history of processing and handling of that specific tile.

Morrissey, Timothy G [ORNL; Fox, Ethan E [ORNL; Wereszczak, Andrew A [ORNL; Ferber, Mattison K [ORNL

2012-06-01T23:59:59.000Z

142

Standardization of the cumulative absolute velocity  

SciTech Connect

EPRI NP-5930, A Criterion for Determining Exceedance of the Operating Basis Earthquake,'' was published in July 1988. As defined in that report, the Operating Basis Earthquake (OBE) is exceeded when both a response spectrum parameter and a second damage parameter, referred to as the Cumulative Absolute Velocity (CAV), are exceeded. In the review process of the above report, it was noted that the calculation of CAV could be confounded by time history records of long duration containing low (nondamaging) acceleration. Therefore, it is necessary to standardize the method of calculating CAV to account for record length. This standardized methodology allows consistent comparisons between future CAV calculations and the adjusted CAV threshold value based upon applying the standardized methodology to the data set presented in EPRI NP-5930. The recommended method to standardize the CAV calculation is to window its calculation on a second-by-second basis for a given time history. If the absolute acceleration exceeds 0.025g at any time during each one second interval, the earthquake records used in EPRI NP-5930 have been reanalyzed and the adjusted threshold of damage for CAV was found to be 0.16g-set.

O'Hara, T.F.; Jacobson, J.P. (Yankee Atomic Electric Co., Bolton, MA (United States))

1991-12-01T23:59:59.000Z

143

Out-of-plane ultrasonic velocity measurement  

DOE Patents (OSTI)

A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated.

Hall, Maclin S. (Marietta, GA); Brodeur, Pierre H. (Smyrna, GA); Jackson, Theodore G. (Atlanta, GA)

1998-01-01T23:59:59.000Z

144

Out-of-plane ultrasonic velocity measurement  

DOE Patents (OSTI)

A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated. 20 figs.

Hall, M.S.; Brodeur, P.H.; Jackson, T.G.

1998-07-14T23:59:59.000Z

145

Laser-Doppler velocimeter for measuring droplet velocities in two-phase liquid-dominated nozzle flows  

DOE Green Energy (OSTI)

A new laser-Doppler velocimeter (LDV) arrangement for measuring droplet velocities in high velocity, liquid-dominated two-phase nozzle flows was developed. The transmitting optics arrangement for this LDV system is identical to that of a dual beam heterodyne LDV, i.e., the light beam from a single frequency argon laser is divided into two parallel identical beams, which are focused to an intersection volume in the flow. The light backscattered from droplets traveling through this volume is collected for analysis using a scanning confocal Fabry-Perot interferometer (FPI). Because of the dual beam arrangement an unscattered or reference beam is not necessary, and the optical alignment ease and stability are greatly improved over similar LDV-FPI systems. Results of droplet velocity measurements in high velocity, high droplet concentration nozzle jet flows are presented.

Alger, T.W.; Crowe, C.T.; Giedt, W.H.

1978-01-01T23:59:59.000Z

146

A Hypothetical Burning-Velocity Formula for Very Lean Hydrogen-Air Mixtures  

E-Print Network (OSTI)

K. Fig. 2 Comparisons of burning-velocity predictions withcurve), when an experimental burning velocity (points) of 53and calculated laminar burning velocities of lean hydrogen-

Grcar, Joseph F

2008-01-01T23:59:59.000Z

147

Initial Examination of Low Velocity Sphere Impact of Glass Ceramics  

Science Conference Proceedings (OSTI)

This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (energy of impact and the elastic property mismatch between sphere and target material. Quasistatic spherical indentation was also performed on both glass ceramics and their contact damage responses were compared to those of soda-lime silicate and borosilicate glasses. Lastly, variability of contact damage response was assessed by performing spherical indentation testing across the area of an entire glass ceramic tile. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Resistan{trademark}-L glass ceramic required the highest velocity of sphere impact for damage to initiate. Starphire{reg_sign} soda-lime silicate glass was second best, then Resistan{trademark}-G1 glass ceramic, and then BOROFLOAT{reg_sign} borosilicate glass. (2) Glass-ceramic Resistan{trademark}-L also required the largest force to initiate ring crack from quasi-static indentation. That ranking was followed, in descending order, by Starphire{reg_sign} soda-lime silicate glass, Resistan{trademark}-G1 glass ceramic, and BOROFLOAT{reg_sign} borosilicate glass. (3) Spheres with a lower elastic modulus require less force to initiate fracture in Resistan{trademark}-G1 from quasi-static spherical indentation. This indicates that friction is affecting ring crack initiation in Resistan{trademark}-G1. Friction also affected ring crack initiation in Starphire{reg_sign} soda-lime silicate and BOROFLOAT{reg_sign} borosilicate glasses. Among these three materials, friction was the most pronounced (largest slope in the RCIF-elastic modulus graph) in the Starphire{reg_sign} and least pronounced in the BOROFLOAT{reg_sign}. The reason for this is not understood, but differences in deformation behavior under high contact stresses could be a cause or contributor to this. (4) The force necessary to initiate contact-induced fracture is higher under dynamic conditions than it is under quasi-static conditions in Resistan{trademark}-L and Resistan{trademark}-G1 glass ceramics. This is a trend observed too in Starphire{reg_sign} and BOROFLOAT{reg_sign}. (5) There is a subtle indication there was intra-tile differences in spherical indentation-induced ring crack initiation forces. This is not a material property nor is it exclusive to glass-ceramic Resistan{trademark}-G1 glass ceramic, rather, it is a statistical mechanical response to an accumulated history of processing and handling of that specific tile.

Morrissey, Timothy G [ORNL; Fox, Ethan E [ORNL; Wereszczak, Andrew A [ORNL; Ferber, Mattison K [ORNL

2012-06-01T23:59:59.000Z

148

high  

Gasoline and Diesel Fuel Update (EIA)

0 0 Highlights International Oil Markets Prices. We have raised our world oil price projection by about $2 per barrel for this month because of assumed greater compliance by OPEC to targeted cuts, especially for the second quarter of 2000 (Figure 1). The expected decline in world petroleum inventories continues (Figure 2), and, given the generally stiff resolve of OPEC members to maintain production cuts, any sign of a turnaround in stocks may be postponed until later this year than previously assumed (Q3 instead of Q2). Our current estimate for the average import cost this past January is now $25 per barrel, a nearly $15-per-barrel increase from January 1999. Crude oil prices are expected to remain at relatively high levels for the first half of 2000, but

149

Simultaneous Measurements of Drop Size and Velocity in ...  

Science Conference Proceedings (OSTI)

... of entrained air velocity. An example is presented in Prahl and Wendt (1988) and Wendt and Prahl (1986) where the authors ...

150

Modified definition of group velocity and electromagnetic energy conservation equation  

E-Print Network (OSTI)

The classical definition of group velocity has two flaws: (a) the group velocity can be greater than the phase velocity in a non-dispersive medium; (b) the definition is not consistent with the principle of relativity. To remove the flaws, a modified definition is proposed. A criterion is set up to identify the justification of group velocity definition. A "superluminal power flow" is constructed to show that the electromagnetic energy conservation equation cannot uniquely define the power flow if the principle of Fermat is not taken into account.

Changbiao Wang

2013-06-13T23:59:59.000Z

151

New Insights Into Deep Convective Core Vertical Velocities Using...  

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

Insights Into Deep Convective Core Vertical Velocities Using ARM UHF Wind Profilers For original submission and image(s), see ARM Research Highlights http:www.arm.govscience...

152

Temporal Velocity Variations beneath the Coso Geothermal Field...  

Open Energy Info (EERE)

events and determine the compressional and shear wave velocity as well as their ratio. In a first step, we apply traveltime tomography based on the observed microearthquake...

153

P wave velocity variations in the Coso region, California, derived...  

Open Energy Info (EERE)

P wave velocity variations in the Coso region, California, derived from local earthquake travel times Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal...

154

Two-dimensional Imaging Velocity Interferometry: Technique and Data Analysis  

Science Conference Proceedings (OSTI)

We describe the data analysis procedures for an emerging interferometric technique for measuring motion across a two-dimensional image at a moment in time, i.e. a snapshot 2d-VISAR. Velocity interferometers (VISAR) measuring target motion to high precision have been an important diagnostic in shockwave physics for many years Until recently, this diagnostic has been limited to measuring motion at points or lines across a target. We introduce an emerging interferometric technique for measuring motion across a two-dimensional image, which could be called a snapshot 2d-VISAR. If a sufficiently fast movie camera technology existed, it could be placed behind a traditional VISAR optical system and record a 2d image vs time. But since that technology is not yet available, we use a CCD detector to record a single 2d image, with the pulsed nature of the illumination providing the time resolution. Consequently, since we are using pulsed illumination having a coherence length shorter than the VISAR interferometer delay ({approx}0.1 ns), we must use the white light velocimetry configuration to produce fringes with significant visibility. In this scheme, two interferometers (illuminating, detecting) having nearly identical delays are used in series, with one before the target and one after. This produces fringes with at most 50% visibility, but otherwise has the same fringe shift per target motion of a traditional VISAR. The 2d-VISAR observes a new world of information about shock behavior not readily accessible by traditional point or 1d-VISARS, simultaneously providing both a velocity map and an 'ordinary' snapshot photograph of the target. The 2d-VISAR has been used to observe nonuniformities in NIF related targets (polycrystalline diamond, Be), and in Si and Al.

Erskine, D J; Smith, R F; Bolme, C; Celliers, P; Collins, G

2011-03-23T23:59:59.000Z

155

Tracking granules at the Sun's surface and reconstructing velocity fields. II. Error analysis  

E-Print Network (OSTI)

The determination of horizontal velocity fields at the solar surface is crucial to understanding the dynamics and magnetism of the convection zone of the sun. These measurements can be done by tracking granules. Tracking granules from ground-based observations, however, suffers from the Earth's atmospheric turbulence, which induces image distortion. The focus of this paper is to evaluate the influence of this noise on the maps of velocity fields. We use the coherent structure tracking algorithm developed recently and apply it to two independent series of images that contain the same solar signal. We first show that a k-\\omega filtering of the times series of images is highly recommended as a pre-processing to decrease the noise, while, in contrast, using destretching should be avoided. We also demonstrate that the lifetime of granules has a strong influence on the error bars of velocities and that a threshold on the lifetime should be imposed to minimize errors. Finally, although solar flow patterns are easily recognizable and image quality is very good, it turns out that a time sampling of two images every 21 s is not frequent enough, since image distortion still pollutes velocity fields at a 30% level on the 2500 km scale, i.e. the scale on which granules start to behave like passive scalars. The coherent structure tracking algorithm is a useful tool for noise control on the measurement of surface horizontal solar velocity fields when at least two independent series are available.

R. Tkaczuk; M. Rieutord; N. Meunier; T. Roudier

2007-07-13T23:59:59.000Z

156

Effect of temperature on wave velocities in sands and sandstones with heavy hydrocarbons  

SciTech Connect

A laboratory investigation was made of the effects of temperature on wave velocities in well cemented Massillon and Boise sandstones and unconsolidated Ottawa sand saturated with heavy hydrocarbons, as well as the dependence of compressional velocities in the hydrocarbons themselves as a function of temperature. The hydrocarbons selected as pore saturants were a commercial paraffin wax, 1-Eicosene, natural heavy crude, and natural tar. The experimental results show that the compressional wave velocities in the hydrocarbons decrease markedly with increasing temperature. In contrast wave velocities in the Massillon and Boise sandstones and unconsolidated Ottawa sand saturated with air or water decrease only little with increasing temperatures. The main reason for the large decreases in rocks with hydrocarbons is the melting of solid hydrocarbons, and high pore pressure. Thermal expansion of the saturants, and possibly thermal cracking of the heavy fractions and vaporization of the light fractions of the hydrocarbons may also contribute. The large decreases of the compressional and shear wave velocities in the hydrocarbon-saturated rocks and sands with temperature, suggest that seismic measurements such as used in seismology or borehole tomography may be very useful in detecting steam fronts in heavy hydrocarbon reservoirs undergoing steam flooding.

Wang, Z.; Nur, A.M.

1986-01-01T23:59:59.000Z

157

Velocity measurements in the near field of a diesel fuel injector by ultrafast imagery  

E-Print Network (OSTI)

This paper examines the velocity profile of fuel issuing from a high-pressure single-orifice diesel injector. Velocities of liquid structures were determined from time-resolved ultrafast shadow images, formed by an amplified two-pulse laser source coupled to a double-frame camera. A statistical analysis of the data over many injection events was undertaken to map velocities related to spray formation near the nozzle outlet as a function of time after start of injection. These results reveal a strong asymmetry in the liquid profile of the test injector, with distinct fast and slow regions on opposite sides of the orifice. Differences of ~100 m/s can be observed between the 'fast' and 'slow' sides of the jet, resulting in different atomization conditions across the spray. On average, droplets are dispersed at a greater distance from the nozzle on the 'fast' side of the flow, and distinct macrostructure can be observed under the asymmetric velocity conditions. The changes in structural velocity and atomization b...

Sedarsky, David

2013-01-01T23:59:59.000Z

158

Vertical Velocities in Continental Boundary Layer Stratocumulus...  

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

- Persist of long time-scales * Impact on radiation budget - High SW albedo compared to land or ocean Klein and Hartmann 1993 But Why Continental Clouds? * They do exist -...

159

Measurements of Laminar Flame Velocity for Components of Natural Gas  

E-Print Network (OSTI)

Measurements of Laminar Flame Velocity for Components of Natural Gas Patricia Dirrenberger1 flame velocity of components of natural gas, methane, ethane, propane, and nbutane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been

160

Multiple mapping conditioning of velocity in turbulent jet flames  

Science Conference Proceedings (OSTI)

Multiple mapping conditioning (MMC) has emerged as a new approach to model turbulent reacting flows. This study revises the standard MMC closure for velocity in turbulent jet flows from linearity in the reference space to linearity in the composition space. This modeling amendment ensures that the standard velocity model in conditional moment closure studies can now be used for MMC computation as well. A simplified model for the velocity-dependence of MMC drift coefficients is derived without loss of generality and is implemented for the revised velocity closure. Modeling results have been corroborated against the Direct Numerical Simulation database of a spatially evolving, planar turbulent jet flame. The revised model shows marked improvement over standard MMC closure in predicting velocity statistics close to the nozzle. (author)

Vaishnavi, P. [Mechanical Engineering Department, Imperial College, London SW7 2AZ (United Kingdom); Kronenburg, A. [Institut fuer Technische Verbrennung, Universitaet Stuttgart, 70174 Stuttgart (Germany)

2010-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

An Adaptive Dealiasing Method Based on Variational Analysis for Radar Radial Velocities Scanned with Small Nyquist Velocities  

Science Conference Proceedings (OSTI)

Previous velocity–azimuth display (VAD)-based methods of dealiasing folded radial velocities have relied heavily on the VAD uniform-wind assumption and, thus, can fail when the uniform-wind assumption becomes poor around azimuthal circles in a ...

Qin Xu; Kang Nai

2012-12-01T23:59:59.000Z

162

Local Equation of State and Velocity Distributions of a Driven Granular Gas  

E-Print Network (OSTI)

We present event-driven simulations of a granular gas of inelastic hard disks with incomplete normal restitution in two dimensions between vibrating walls (without gravity). We measure hydrodynamic quantities such as the stress tensor, density and temperature profiles, as well as velocity distributions. Relating the local pressure to the local temperature and local density, we construct a local constitutive equation. For strong inelasticities the local constitutive relation depends on global system parameters, like the volume fraction and the aspect ratio. For moderate inelasticities the constitutive relation is approximately independent of the system parameters and can hence be regarded as a local equation of state, even though the system is highly inhomogeneous with heterogeneous temperature and density profiles arising as a consequence of the energy injection. Concerning the local velocity distributions we find that they do not scale with the square root of the local granular temperature. Moreover the high-velocity tails are different for the distribution of the x- and the y-component of the velocity, and even depend on the position in the sample, the global volume fraction, and the coefficient of restitution.

Olaf Herbst; Peter Müller; Matthias Otto; Annette Zippelius

2004-02-04T23:59:59.000Z

163

SIMULATIONS OF EARLY BARYONIC STRUCTURE FORMATION WITH STREAM VELOCITY. II. THE GAS FRACTION  

SciTech Connect

Understanding the gas content of high-redshift halos is crucial for studying the formation of the first generation of galaxies and reionization. Recently, Tseliakhovich and Hirata showed that the relative 'stream' velocity between the dark matter and baryons at the time of recombination-formally a second-order effect, but an unusually large one-can influence the later structure formation history of the universe. We quantify the effect of the stream velocity on the so-called characteristic mass-the minimum mass of a dark matter halo capable of retaining most of its baryons throughout its formation epoch-using three different high-resolution sets of cosmological simulations (with separate transfer functions for baryons and dark matter) that vary in box size, particle number, and the value of the relative velocity between the dark matter and baryons. In order to understand this effect theoretically, we generalize the linear theory filtering mass to properly account for the difference between the dark matter and baryonic density fluctuation evolution induced by the stream velocity. We show that the new filtering mass provides an accurate estimate for the characteristic mass, while other theoretical ansatzes for the characteristic mass are substantially less precise.

Naoz, Smadar [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yoshida, Naoki [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)] [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Gnedin, Nickolay Y., E-mail: snaoz@cfa.harvard.edu [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2013-01-20T23:59:59.000Z

164

Correlation of turbulent burning velocities of ethanol-air, measured in a fan-stirred bomb up to 1.2 MPa  

SciTech Connect

The turbulent burning velocity is defined by the mass rate of burning and this also requires that the associated flame surface area should be defined. Previous measurements of the radial distribution of the mean reaction progress variable in turbulent explosion flames provide a basis for definitions of such surface areas for turbulent burning velocities. These inter-relationships. in general, are different from those for burner flames. Burning velocities are presented for a spherical flame surface, at which the mass of unburned gas inside it is equal to the mass of burned gas outside it. These can readily be transformed to burning velocities based on other surfaces. The measurements of the turbulent burning velocities presented are the mean from five different explosions, all under the same conditions. These cover a wide range of equivalence ratios, pressures and rms turbulent velocities for ethanol-air mixtures. Two techniques are employed, one based on measurements of high speed schlieren images, the other on pressure transducer measurements. There is good agreement between turbulent burning velocities measured by the two techniques. All the measurement are generalised in plots of burning velocity normalised by the effective unburned gas rms velocity as a function of the Karlovitz stretch factor for different strain rate Markstein numbers. For a given value of this stretch factor a decrease in Markstein number increases the normalised burning velocity. Comparisons are made with the findings of other workers. (author)

Bradley, D.; Lawes, M.; Mansour, M.S. [School of Mechanical Engineering, University of Leeds (United Kingdom)

2011-01-15T23:59:59.000Z

165

Field-effect transistor having a superlattice channel and high carrier velocities at high applied fields  

DOE Patents (OSTI)

A field effect transistor comprises a semiconductor having a source, a drain, a channel and a gate in operational relationship. The semiconductor is a strained layer superlattice comprising alternating quantum well and barrier layers, the quantum well layers and barrier layers being selected from the group of layer pairs consisting of InGaAs/AlGaAs, InAs/InAlGaAs, and InAs/InAlAsP. The layer thicknesses of the quantum well and barrier layers are sufficiently thin that the alternating layers constitute a superlattice which has a superlattice conduction band energy level structure in k-vector space which includes a lowest energy .GAMMA.-valley and a next lowest energy L-valley, each k-vector corresponding to one of the orthogonal directions defined by the planes of said layers and the directions perpendicular thereto. The layer thicknesses of the quantum well layers are selected to provide a superlattice L.sub.2D -valley which has a shape which is substantially more two-dimensional than that of said bulk L-valley.

Chaffin, deceased, Roger J. (late of Albuquerque, NM); Dawson, Ralph (Albuquerque, NM); Fritz, Ian J. (Albuquerque, NM); Osbourn, Gordon C. (Albuquerque, NM); Zipperian, Thomas E. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

166

Field-effect transistor having a superlattice channel and high carrier velocities at high applied fields  

DOE Patents (OSTI)

A field effect transistor comprises a semiconductor having a source, a drain, a channel and a gate in operational relationship. The semiconductor is a strained layer superlattice comprising alternating quantum well and barrier layers, the quantum well layers and barrier layers being selected from the group of layer pairs consisting of InGaAs/AlGaAs, InAs/InAlGaAs, and InAs/InAlAsP. The layer thicknesses of the quantum well and barrier layers are sufficiently thin that the alternating layers constitute a superlattice which has a superlattice conduction band energy level structure in k-vector space. The layer thicknesses of the quantum well layers are selected to provide a superlattice L/sub 2D/-valley which has a shape which is substantially more two-dimensional than that of said bulk L-valley. 2 figs.

Chaffin, R.J.; Dawson, L.R.; Fritz, I.J.; Osbourn, G.C.; Zipperian, T.E.

1987-06-08T23:59:59.000Z

167

Composite Vertical Structure of Vertical Velocity in Nonprecipitating Cumulus Clouds  

Science Conference Proceedings (OSTI)

Vertical transects of Doppler vertical velocity data, obtained from an airborne profiling millimeter-wave cloud radar, are composited for a large number of cumulus clouds (Cu) at various stages of their life cycle, to examine typical circulations ...

Yonggang Wang; Bart Geerts

2013-05-01T23:59:59.000Z

168

Efficient Dealiasing of Doppler Velocities Using Local Environment Constraints  

Science Conference Proceedings (OSTI)

A Doppler velocity dealiasing algorithm is described that processes one radial at a time by comparing that radial with a previous radial. This technique has worked reliably on numerous Doppler radar datasets for clear air, thunderstorm, and ...

Michael D. Eilts; Steven D. Smith

1990-02-01T23:59:59.000Z

169

Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field,  

Open Energy Info (EERE)

Velocity And Attenuation Structure Of The Geysers Geothermal Field, Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Details Activities (1) Areas (1) Regions (0) Abstract: The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. A key resource management issue at this field is the distribution of fluid in the matrix of the reservoir rock. In this paper, we interpret seismic compressional-wave velocity and quality quotient (Q) data at The Geysers in terms of the geologic structure and fluid saturation in the reservoir. Our data consist of waveforms from approximately 300

170

Y-12 Site Experience with Deposition Velocity Issues  

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

Site Experience with Site Experience with Deposition Velocity Issues Douglas Clark Analyst B&W Technical Services Y-12 May 9, 2012 Y-12 Site Experience with Deposition Velocity Issues Y-12 Specific Issues Y-12 Site Experience with Deposition Velocity Issues Windspeed - Calm Wind Conditions at Y-12 Site Y-12 Site Experience with Deposition Velocity Issues Windspeed - Stability Class Determinations * NRC RG 1.23 ΔT-only method * EPA-454/R-99-005 solar- radiation-delta-temperature (SRDT) method * Hybrid SR - DT method * wind direction standard deviation [sigma-theta (σ θ )] * elevation angle standard deviation [sigma-phi (σ φ )] * vertical wind speed standard deviation [sigma-omega (σ ω )], * wind-speed ratio method (u R ) * All evaluated using data from west

171

Vertical Velocity Structures in an Axisymmetric, Nonhydrostatic Tropical Cyclone Model  

Science Conference Proceedings (OSTI)

A statistical analysis of several experiments with different microphysical parameterizations in an axisymmetric, nonhydrostatic tropical cyclone model illustrates the impact of icc-phase microphysics on model vertical velocity structure. The ...

Stephen J. Lord; Jacqueline M. Lord

1988-05-01T23:59:59.000Z

172

Detiding Three-Dimensional Velocity Survey Data in Coastal Waters  

Science Conference Proceedings (OSTI)

A three-dimensional data interpolation technique is proposed that efficiently removes tidal currents from spatial velocity surveys. The least squares method extends prior two-dimensional detiding methods to three spatial dimensions using ...

Andreas Münchow

2000-05-01T23:59:59.000Z

173

The Finescale Response of Lowered ADCP Velocity Profiles  

Science Conference Proceedings (OSTI)

Lowered acoustic Doppler current profiler (LADCP) velocity profiles are compared with simultaneous higher-resolution expendable current profiler (XCP) profiles to determine the lowered ADCP's response at short wavelengths. Although lowered ADCP ...

Kurt Polzin; Eric Kunze; Jules Hummon; Eric Firing

2002-02-01T23:59:59.000Z

174

Mass Transport Velocity in Free Barotropic Poincaré Waves  

Science Conference Proceedings (OSTI)

The mass transport velocity induced by long surface waves in a shallow, rotating viscous ocean is studied theoretically by using a Lagrangian description of motion. The depth is constant, and the water is homogeneous. Such waves are referred to ...

Frode Høydalsvik; Jan Erik Weber

2003-09-01T23:59:59.000Z

175

TOPS: A Free-Fall Velocity and CTD Profiler  

Science Conference Proceedings (OSTI)

A free-fall instrument, TOPS, measures vertical profiles of horizontal ocean velocity, conductivity and temperature. Profiling capability extends throughout the full water column (6000 db pressure limitation). Larger vertical wavelength (water ...

S. P. Hayes; H. B. Milburn; E. F. Ford

1984-09-01T23:59:59.000Z

176

LOW VELOCITY SHPERE IMPACT OF SODA LIME SILICATE GLASS  

Science Conference Proceedings (OSTI)

This report summarizes TARDEC-sponsored work at Oak Ridge National Laboratory (ORNL) during the FY11 involving low velocity ( 30 m/s or 65 mph) ball impact testing of Starphire soda lime silicate glass. The intent was to better understand low velocity impact response in the Starphire for sphere densities that bracketed that of rock. Five sphere materials were used: borosilicate glass, soda-lime silicate glass, steel, silicon nitride, and alumina. A gas gun was fabricated to produce controlled velocity delivery of the spheres against Starphire tile targets. Minimum impact velocities to initiate fracture in the Starphire were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the any of the five sphere-Starphire-target combinations.

Morrissey, Timothy G [ORNL; Fox, Ethan E [ORNL; Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL

2012-01-01T23:59:59.000Z

177

Representation of Velocity Gradient Effects in a Gaussian Puff Model  

Science Conference Proceedings (OSTI)

The Gaussian puff model framework is extended to provide a description of velocity shear distortion effects. An efficient splitting-merging algorithm is presented so that a maximum puff size can be specified for a calculation. This localizes the ...

R. I. Sykes; D. S. Henn

1995-12-01T23:59:59.000Z

178

Equatorial Atlantic Velocity and Temperature Observations: February–November 1981  

Science Conference Proceedings (OSTI)

Upper ocean velocity and temperature measurements were obtained in the central equatorial Atlantic using surface moored current meters from February to November 1981. Distinct seasonal variations were observed in the zonal momentum and ...

R. H. Weisberg

1985-05-01T23:59:59.000Z

179

Simulation of Three-Dimensional Turbulent Velocity Fields  

Science Conference Proceedings (OSTI)

New algorithms for the simulation of three-dimensional homogeneous turbulent velocity fields are compared with standard spectral domain algorithms. Results are presented for a von Kármán model of the covariance tensor. For typical atmospheric ...

Rod Frehlich; Larry Cornman; Robert Sharman

2001-02-01T23:59:59.000Z

180

A New Relationship between Mean Doppler Velocity and Differential Reflectivity  

Science Conference Proceedings (OSTI)

A new relationship has been established linking the vertical mean Doppler velocity of raindrop spectra and the accompanying differential reflectivities. It is based upon the specific radar combination of a vertically pointing Doppler and a ...

Matthias Steiner

1991-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Dealiasing of Doppler Radar Velocities Using a Torus Mapping  

Science Conference Proceedings (OSTI)

A novel dealiasing algorithm for Doppler radar velocity data has been developed at the Swedish Meteorological and Hydrological Institute (SMHI). Unlike most other methods, it does not need independent wind information from other instruments (e.g.,...

Günther Haase; Tomas Landelius

2004-10-01T23:59:59.000Z

182

Eulerian and Lagrangian Velocity Distributions in the North Atlantic  

Science Conference Proceedings (OSTI)

Velocity probability density functions (PDFs) are calculated using data from subsurface current meters in the western North Atlantic Ocean. The PDFs are weakly, but significantly, non-Gaussian. They deviate from normality because of an excess of ...

J. H. LaCasce

2005-12-01T23:59:59.000Z

183

Benthic Boundary-Layer Velocity Profiles: Dependence on Averaging Period  

Science Conference Proceedings (OSTI)

The relationship between benthic boundary-layer velocity profiles and current meter averaging time is investigated using detailed (0.61 Hz) current measurements recorded within 1 m of the bottom on the inner continental shelf. The percentage of ...

Barry M. Lesht

1980-06-01T23:59:59.000Z

184

GPS velocity field for the Tien Shan and surrounding regions  

E-Print Network (OSTI)

Measurements at ?400 campaign-style GPS points and another 14 continuously recording stations in central Asia define variations in their velocities both along and across the Kyrgyz and neighboring parts of Tien Shan. They ...

Zubovich, Alexander V.

185

Profiler Measurements of Vertical Velocity Fluctuations in the Ocean  

Science Conference Proceedings (OSTI)

A method is described for measuring the vertical component of velocity fluctuations due to three-dimensional turbulence in the ocean from a freely falling microstructure profiler. The dynamic pressure measurement relies on a commercially ...

J. N. Moum

1990-04-01T23:59:59.000Z

186

Deep Velocity Measurements in the Western Equatorial Indian Ocean  

Science Conference Proceedings (OSTI)

Vertical profiles of horizontal current collected in April and June 1979 in the western Indian Ocean revealed the presence of short vertical scale (150–300 m) deep zonal jets, trapped to within 1° of the equator. Meridional velocity records ...

Rui M. Ponte; James Luyten

1990-01-01T23:59:59.000Z

187

Platform-Motion Correction of Velocity Measured by Doppler Lidar  

Science Conference Proceedings (OSTI)

The NOAA/Earth System Research Laboratory (ESRL) has two coherent Doppler lidar systems that have been deployed on board research vessels to obtain data during several experiments. The instruments measure the wind velocity relative to the motion ...

Reginald J. Hill; W. Alan Brewer; Sara C. Tucker

2008-08-01T23:59:59.000Z

188

Estimating fracture parameters from p-wave velocity profiles about a geothermal well  

DOE Green Energy (OSTI)

The feasibility of locating fracture zones and estimating their crack parameters was examined using an areal well shoot method centered on Utah State Geothermal Well 9-1, Beaver County, Utah. High-resolution travel time measurements were made between a borehole sensor and an array of shot stations distributed radially and azimuthally about the well. Directional velocity behavior in the vicinity of the well was investigated by comparing velocity logs derived from the travel time data. Three fracture zones were identified form the velocity data, corroborating fracture indicators seen in other geophysical logs conducted in Well 9-1. Crack densities and average crack aspect ratios for these fracture zones were estimated using a self-consistent velocity theory (O'Connell and Budiansy 1974). Probable trends of these fracture zones were established from a combination of the data from the more distant shot stations and the results of a gravity survey. The results of this study indicate that the areal well shoot is a potentially powerful tool for the reconnaisance of fracture-controlled fluid and gas reservoirs. Improvements in methodology and hardware could transform it into an operationally viable survey method.

Jenkinson, J.T.; Henyey, T.L.; Sammis, C.G.; Leary, P.C.; McRaney, J.K.

1981-12-01T23:59:59.000Z

189

The Rossiter-McLaughlin effect and analytic radial velocity curves for transiting extrasolar planetary systems  

E-Print Network (OSTI)

A transiting extrasolar planet sequentially blocks off the light coming from the different parts of the disk of the host star in a time dependent manner. Due to the spin of the star, this produces an asymmetric distortion in the line profiles of the stellar spectrum, leading to an apparent anomaly of the radial velocity curves, known as the Rossiter - McLaughlin effect. Here, we derive approximate but accurate analytic formulae for the anomaly of radial velocity curves taking account of the stellar limb darkening. The formulae are particularly useful in extracting information of the projected angle between the planetary orbit axis and the stellar spin axis, \\lambda, and the projected stellar spin velocity, V sin I_s. We create mock samples for the radial curves for the transiting extrasolar system HD209458, and demonstrate that constraints on the spin parameters (V sin I_s, \\lambda) may be significantly improved by combining our analytic template formulae and the precision velocity curves from high-resolution spectroscopic observations with 8-10 m class telescopes. Thus future observational exploration of transiting systems using the Rossiter - McLaughlin effect is one of the most important probes to better understanding of the origin of extrasolar planetary systems, especially the origin of their angular momentum.

Yasuhiro Ohta; Atsushi Taruya; Yasushi Suto

2004-10-21T23:59:59.000Z

190

VELOCITY EVOLUTION AND THE INTRINSIC COLOR OF TYPE Ia SUPERNOVAE  

SciTech Connect

To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II {lambda}6355 and Ca II H and K are related to the B - V color at peak brightness. We find that the maximum-light velocity of Si II {lambda}6355 and Ca II H and K and the maximum-light pseudo-equivalent width of Si II {lambda}6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II {lambda}6355 measurements. Ca II H and K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia-even after removing a linear trend with velocity-indicating that lower-velocity SNe Ia are more 'standard crayons'. Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.

Foley, Ryan J.; Sanders, Nathan E.; Kirshner, Robert P., E-mail: rfoley@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-12-01T23:59:59.000Z

191

Design of regulated velocity flow assurance device for petroleum industry  

E-Print Network (OSTI)

The petroleum industry faces problems in transportation of crude petroleum be- cause of the deposition of paraffins, hydrates and asphaltenes on the insides of the pipeline. These are conventionally removed using either chemical inhibitors or mechani- cal devices, called pigs, which travel through the pipeline and mechanically scrape away the deposits. These pigs are propelled by the pipeline product itself and hence travel at the same velocity as the product. Research has indicated that cleaning would be better if the pigs are traveling at a relatively constant velocity of around 70% of the product velocity. This research utilizes the concept of regulating the bypass flow velocity in order to maintain the pig velocity. The bypass flow is regulated by the control unit based on the feedback from the turbine flowmeter, which monitors the bypass flow. A motorized butterfly valve is used for actually controlling the bypass flow. In addition to cleaning, the proposed pig utilizes on-board electronics like accelerom- eter and pressure transducers to store the data gathered during the pig run. This data can then be analyzed and the condition of the pipeline predicted. Thus, this research addresses the problem of designing a pig to maintain a constant velocity in order to achieve better cleaning. It also helps gather elementary data that can be used to predict the internal conditions in the pipe.

Yardi, Chaitanya Narendra

2004-12-01T23:59:59.000Z

192

Precipitation Identification from Radar Wind Profiler Spectral Moment Data: Vertical Velocity Histograms, Velocity Variance, and Signal Power–Vertical Velocity Correlations  

Science Conference Proceedings (OSTI)

Correlations between range-corrected signal power Src and radial vertical velocity Vr, from the vertical beam of a UHF wind profiler can be used to distinguish between air- and precipitation-dominated echoes using an Src–Vr correlation diagram. ...

F. Martin Ralph; Paul J. Neiman; Dominique Ruffieux

1996-06-01T23:59:59.000Z

193

Mechanical joining with self piercing solid-rivets at elevated tool velocities  

Science Conference Proceedings (OSTI)

In the present paper the influence of a higher setting velocity in the joining process of self piercing solid-rivets is shown. In the conventional process tool velocities well below 1 m/s are common. The present research results show the potential of increasing them in the range of about 5 m/s. The results are especially relevant for joining high-strength steels. These steel sheets often cause problems in the process of riveting mixed materials, e. g. aluminium-steel compound. The high strength of the steel sometimes leads to undesirable material flow in the joining process or unwanted burr development. These effects, which are described in detail in the article, can be reduced significantly for the investigated cases by the use of higher tool velocities. Using a high speed camera and a load cell, a test setup based on a drop tower was realized. It was used to time the force signals and the motion profile of the high speed riveting process. The results of the force analysis show an oscillating force progression. Within a numerical research the principal effects influencing the results of the riveting process can be shown. It was found that the pulse-like force transmission between riveting machine and punch, results in various vibrations especially of long and thin tool parts. Hence the rivet penetrates the sheet metal with non-uniform velocities. As a result the early indentation of die into the lower sheet metal at the beginning of the process is reduced, so that the final process step provides a sufficient material flow into the circular rivet groove. A strain-rate dependent process model with elastic tool properties and consideration of inertia effects is presented.

Neugebauer, R.; Jesche, F.; Kraus, C.; Hensel, S. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Reichenhainer Strasse 88, 09126 Chemnitz (Germany)

2011-05-04T23:59:59.000Z

194

Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners  

SciTech Connect

Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

2008-10-01T23:59:59.000Z

195

DEPOSITION VELOCITY ESTIMATION WITH THE GENII V2 SOFTWARE  

SciTech Connect

In 2010, the Department of Energy (DOE) Chief of Nuclear Safety and Office of Health, Safety and Security (HSS), with the support of industry experts in atmospheric sciences and accident dose consequences analysis, performed detailed analyses of the basis for the dry deposition velocity (DV) values used in the MACCS2 computer code. As a result of these analyses, DOE concluded that the historically used default DV values of 1 centimeter/second (cm/s) for unfiltered/unmitigated releases and 0.1 cm/s for filtered/mitigated releases may not be reasonably conservative for all DOE sites and accident scenarios. HSS recently issued Safety Bulletin 2011-02, Accident Analysis Parameter Update, recommending the use of the newly developed default DV, 0.1 cm/s for an unmitigated/unfiltered release. Alternatively site specific DV values can be developed using GENII version 2 (GENII v2) computer code. Key input parameters for calculating DV values include surface roughness, maximum wind speed for calm, particle size, particle density and meteorological data (wind speed and stability class). This paper will include reasonably conservative inputs, and a truncated parametric study. In lieu of the highly-conservative recommended DV value (0.1cm/s) for unmitigated/unfiltered release, GENII v2 has been used to justify estimated 95th percentile DV values. Also presented here are atmospheric dilution factors ({chi}/Q values) calculated with the MACCS2 code using the DV values form GENII v2, {chi}/Q values calculated directly with GENII v2, and a discussion of these results compare with one another. This paper will give an overview of the process of calculating DV with GENII v2 including a discussion of the sensitivity of input parameters.

Hutchins, H.

2012-04-23T23:59:59.000Z

196

Exceptional Ground Accelerations and Velocities Caused by Earthquakes  

Science Conference Proceedings (OSTI)

This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this vector peak. Accelerations in the top 100 come from earthquakes as small as magnitude 5, while velocities in the top 100 all come from earthquakes with magnitude 6 or larger. Records are dominated by crustal earthquakes with thrust, oblique-thrust, or strike-slip mechanisms. Normal faulting mechanisms in crustal earthquakes constitute under 5% of the records in the databases searched, and an even smaller percentage of the exceptional records. All NEHRP site categories have contributed exceptional records, in proportions similar to the extent that they are represented in the larger database.

Anderson, John

2008-01-17T23:59:59.000Z

197

An Improved Gaussian Jet Model for Deriving Absolute Geostrophic Velocity from Satellite Altimetry  

Science Conference Proceedings (OSTI)

Key aspects of a Gaussian jet model for deriving absolute geostrophic velocity from TOPEX/Poseidon altimeter data are improved. Velocities are obtained by synthesizing Gaussian fits to cross-stream velocity anomaly profiles of the Kuroshio and ...

Seung-Bum Kim; M. A. Saunders

2002-12-01T23:59:59.000Z

198

The Velocity of Money in a Life-Cycle Model  

E-Print Network (OSTI)

The determinants of the velocity of money have been examined based on life-cycle hypothesis. The velocity of money can be expressed by reciprocal of the average value of holding time which is defined as interval between participating exchanges for one unit of money. This expression indicates that the velocity is governed by behavior patterns of economic agents and open a way to constructing micro-foundation of it. It is found that time pattern of income and expense for a representative individual can be obtained from a simple version of life-cycle model, and average holding time of money resulted from the individual's optimal choice depends on the expected length of relevant planning periods.

Wang, Y; Wang, Yougui; Qiu, Hanqing

2005-01-01T23:59:59.000Z

199

MACCS2/Deposition Velocity Workshop | Department of Energy  

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

You are here You are here Home » MACCS2/Deposition Velocity Workshop MACCS2/Deposition Velocity Workshop The Department of Energy's Chief of Nuclear Safety hosted a MACCS2/Deposition Velocity Workshop on June 5-6, 2012, in Germantown, Maryland. Approximately 70 participants attended. The purpose of the workshop was to: Discuss MACCS2 and atmospheric dispersion models as applied to DOE consequence analysis. Discuss implementation of HSS Safety Bulletin 2011-2, Accident Analysis Parameter Update, at field sites. Develop a consistent Department-wide approach for responding to the HSS Safety Bulletin. Identify areas for improved DOE guidance for ensuring defensible consequence analyses. June Workshop Agenda- Final.docx Atmospheric Dispersion Modeling in Safety Analyses; GENII

200

Temporal Velocity Variations beneath the Coso Geothermal Field Observed  

Open Energy Info (EERE)

Velocity Variations beneath the Coso Geothermal Field Observed Velocity Variations beneath the Coso Geothermal Field Observed using Seismic Double Difference Tomography of Compressional and Shear Wave Arrival Times Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Temporal Velocity Variations beneath the Coso Geothermal Field Observed using Seismic Double Difference Tomography of Compressional and Shear Wave Arrival Times Details Activities (1) Areas (1) Regions (0) Abstract: Microseismic imaging can be an important tool for characterizing geothermal reservoirs. Since microseismic sources occur more or less continuously both due to the operations of a geothermal field and the naturally occurring background seismicity, passive seismic monitoring is well suited to quantify the temporal variations in the vicinity of a

Note: This page contains sample records for the topic "high velocity sdhv" 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

Determination of the transverse velocity of Q2237+0305  

E-Print Network (OSTI)

The largest systematic uncertainty present in the analysis of gravitationally microlensed quasar light curves is that of the galactic transverse velocity. We describe a method for determining the transverse velocity as well as its application to published monitoring data of Q2237+0305 (Irwin et al. 1989; Corrigan et al. 1991; Ostensen et al 1995). We find that while this data displays strong evidence for microlensing, it limits the transverse velocity to be < 500 km/sec (for microlens masses of 0.5 solar masses). In addition, by combining these results with a new method for modelling the microlensing contribution of stellar proper motions, we find that the masses of microlenses in Q2237+0305 are consistent with those of low mass stars.

J. S. B. Wyithe

1999-09-21T23:59:59.000Z

202

The Velocity Field of Quasar Broad Emission Line Gas  

E-Print Network (OSTI)

In this Letter, the broad emission line (BEL) profiles of superluminal quasars with apparent jet velocities, $\\beta_{a}>10$, (ultraluminal QSOs, or ULQSOs hereafter) are studied as a diagnostic of the velocity field of the BEL emitting gas in quasars. The ULQSOs are useful because they satisfy a very strict kinematical constraint, their parsec scale jets must be propagating within $12^{\\circ}$ of the line of sight. We know the orientation of these objects with great certainty. The large BEL FWHM, $\\sim 3,000 \\mathrm{km/s} - 6,000 \\mathrm{km/s}$, in ULQSOs tend to indicate that the BEL gas has a larger component of axial velocity (either random or in a wind) along the jet direction than previously thought.

Brian Punsly

2007-01-25T23:59:59.000Z

203

Planar velocity analysis of diesel spray shadow images  

E-Print Network (OSTI)

The focus of this work is to demonstrate how spatially resolved image information from diesel fuel injection events can be obtained using a forward-scatter imaging geometry, and used to calculate the velocities of liquid structures on the periphery of the spray. In order to obtain accurate velocities directly from individual diesel spray structures, those features need to be spatially resolved in the measurement. The distributed structures measured in a direct shadowgraphy arrangement cannot be reliably analyzed for this kind of velocity information. However, by utilizing an intense collimated light source and adding imaging optics which modify the signal collection, spatially resolved optical information can be retrieved from spray edge regions within a chosen object plane. This work discusses a set of measurements where a diesel spray is illuminated in rapid succession by two ultrafast laser pulses generated by a mode-locked Ti-Sapphire oscillator seeding a matched pair of regenerative amplifiers. Light fro...

Sedarsky, David

2012-01-01T23:59:59.000Z

204

Three-dimensional P velocity structure of the crust below Newberry Volcano, Oregon  

SciTech Connect

Utilizing teleseismic P residuals, we have detected a column of high P velocity material extending from within 10 km of the surface below the summit of Newberry Volcano, Oregon to midcrustal depths near 25 km. We interpret this column to be the expression of a swarm of predominantly subsolidus gabbroic sills and dikes which were intruded as the volcano was built. The high P velocities observed below the volcano severely limit the size of magma chambers which could presently exist in the crust below Newberry Volcano. Those possible include a few percent of partial melt distributed through large volumes of a mafic intrusion zone in the midcrust; a few smaller, higher melt fraction zones in the midcrust with dimensions less than 6 km and whose aggregate volume is only a few percent of enclosing volumes of 200 km/sup 3/; small magma bodies with dimensions of a few kilometers located within the upper 10 km of the crust; or a mafic, crystal-rich magma of arbitrary dimensions located in the upper few km. The low P velocities detected in the upper 4 km beneath the center of the summit caldera may be partially caused by a magma chamber in the second of these catagories.

Stauber, D.A.; Green, S.M.; Iyer, H.M.

1988-09-10T23:59:59.000Z

205

Modelling Solar Oscillation Power Spectra: II. Parametric Model of Spectral Lines Observed in Doppler Velocity Measurements  

E-Print Network (OSTI)

We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and damping as these mechanisms remain poorly understood. The model is targeted at the accurate fitting of power spectra coming from Doppler velocity measurements and uses an adaptive response function that accounts for both the vertical and horizontal components of the velocity field on the solar surface and for possible instrumental and observational distortions. The model is continuous in frequency, can easily be adapted to intensity measurements and extends naturally to the analysis of high-frequency pseudo modes (interference peaks at frequencies above the atmospheric acoustic cutoff).

Vorontsov, Sergei V

2013-01-01T23:59:59.000Z

206

On mass and velocity distributions in members of star clusters An analytical approach  

E-Print Network (OSTI)

Dynamical evolution of stellar mass distribution in star clusters is analysed by considering simultaneously the effects of dynamical friction, stochastic heating and the gravitational potential due to mass distribution in the clusters. A simple expression is suggested for the dynamical friction which adequately describes it in both high and low velocity ranges and the effect of mass distribution in the cluster on the dynamics of a test mass can be described by an anharmonic potential. With the help of energy considerations we describe the dispersions in position and in velocity for stars of different masses showing how the slowing down and mass segregation of stars evolve in the cluster. Results are presented with the parameters for the star clusters of our Galaxy.

Chatterjee, S; Sagar, R; Kumar, Brijesh; Sagar, Ram

2002-01-01T23:59:59.000Z

207

On mass and velocity distributions in members of star clusters : An analytical approach  

E-Print Network (OSTI)

Dynamical evolution of stellar mass distribution in star clusters is analysed by considering simultaneously the effects of dynamical friction, stochastic heating and the gravitational potential due to mass distribution in the clusters. A simple expression is suggested for the dynamical friction which adequately describes it in both high and low velocity ranges and the effect of mass distribution in the cluster on the dynamics of a test mass can be described by an anharmonic potential. With the help of energy considerations we describe the dispersions in position and in velocity for stars of different masses showing how the slowing down and mass segregation of stars evolve in the cluster. Results are presented with the parameters for the star clusters of our Galaxy.

S. Chatterjee; Brijesh Kumar; Ram Sagar

2002-11-18T23:59:59.000Z

208

How Required Reserve Ratio Affects Distribution and Velocity of Money  

E-Print Network (OSTI)

In this paper the dependence of wealth distribution and the velocity of money on the required reserve ratio is examined based on a random transfer model of money and computer simulations. A fractional reserve banking system is introduced to the model where money creation can be achieved by bank loans and the monetary aggregate is determined by the monetary base and the required reserve ratio. It is shown that monetary wealth follows asymmetric Laplace distribution and latency time of money follows exponential distribution. The expression of monetary wealth distribution and that of the velocity of money in terms of the required reserve ratio are presented in a good agreement with simulation results.

Xi, N; Wang, Y; Xi, Ning; Ding, Ning; Wang, Yougui

2005-01-01T23:59:59.000Z

209

Edge Turbulence Velocity Changes with Lithium Coating on NSTX  

SciTech Connect

Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________

A. Cao, S.J. Zweben, D.P. Stotler, M. Bell, A. Diallo, S.M. Kaye and B. LeBlanc

2012-08-10T23:59:59.000Z

210

Source shape determination with directional fragment-fragment velocity correlations  

E-Print Network (OSTI)

Correlation functions, constructed from directional projections of the relative velocities of fragments, are used to determine the shape of the breakup volume in coordinate space. For central collisions of 129Xe + natSn at 50 MeV per nucleon incident energy, measured with the 4pi multi-detector INDRA at GSI, a prolate shape aligned along the beam direction with an axis ratio of 1:0.7 is deduced. The sensitivity of the method is discussed in comparison with conventional fragment-fragment velocity correlations.

A. Le Fevre; C. Schwarz; G. Auger; M. L. Begemann-Blaich; N. Bellaize; R. Bittiger; F. Bocage; B. Borderie; R. Bougault; B. Bouriquet; J. L. Charvet; A. Chbihi; R. Dayras; D. Durand; J. D. Frankland; E. Galichet; D. Gourio; D. Guinet; S. Hudan; P. Lautesse; F. Lavaud; R. Legrain; O. Lopez; J. Lukasik; U. Lynen; W. F. J. Mueller; L. Nalpas; H. Orth; E. Plagnol; E. Rosato; A. Saija; C. Sfienti; B. Tamain; W. Trautmann; A. Trzcinski; K. Turzo; E. Vient; M. Vigilante; C. Volant; B. Zwieglinski

2007-11-09T23:59:59.000Z

211

Clutter in the GMTI range-velocity map.  

SciTech Connect

Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.

Doerry, Armin Walter

2009-04-01T23:59:59.000Z

212

THE RADIAL VELOCITY EXPERIMENT (RAVE): THIRD DATA RELEASE  

Science Conference Proceedings (OSTI)

We present the third data release of the RAdial Velocity Experiment (RAVE) which is the first milestone of the RAVE project, releasing the full pilot survey. The catalog contains 83,072 radial velocity measurements for 77,461 stars in the southern celestial hemisphere, as well as stellar parameters for 39,833 stars. This paper describes the content of the new release, the new processing pipeline, as well as an updated calibration for the metallicity based upon the observation of additional standard stars. Spectra will be made available in a future release. The data release can be accessed via the RAVE Web site.

Siebert, A. [Observatoire Astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l'universite, 67000 Strasbourg (France); Williams, M. E. K.; Siviero, A.; Boeche, C.; Steinmetz, M.; De Jong, R. S.; Enke, H.; Anguiano, B. [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Reid, W.; Ritter, A. [Department of Physics and Astronomy, Faculty of Sciences, Macquarie University, NSW 2109, Sydney (Australia); Fulbright, J.; Wyse, R. F. G. [Department of Physics and Astronomy, Johns Hopkins University, 366 Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 (United States); Munari, U. [INAF Osservatorio Astronomico di Padova, 36012 Asiago (Italy); Zwitter, T. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Watson, F. G.; Burton, D.; Cass, C. J. P.; Fiegert, K.; Hartley, M.; Russel, K. S. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia)

2011-06-15T23:59:59.000Z

213

Fermi velocity renormalization and dynamical gap generation in graphene  

E-Print Network (OSTI)

We study the renormalization of the Fermi velocity by the long-range Coulomb interactions between the charge carriers in the Dirac-cone approximation for the effective low-energy description of the electronic excitations in graphene at half filling. Solving the coupled system of Dyson-Schwinger equations for the dressing functions in the corresponding fermion propagator with various approximations for the particle-hole polarization we observe that Fermi velocity renormalization effects generally lead to a considerable increase of the critical coupling for dynamical gap generation and charge-density wave formation at the semimetal-insulator transition.

C. Popovici; C. S. Fischer; L. von Smekal

2013-08-28T23:59:59.000Z

214

Comparative Study of Ultimate Saturation Velocity in Zigzag and Chiral Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Charge transfer mechanism in carbon nanotubes (CNTs) from the scattering-limited Ohmic transport to high-field-initiated ballistic transport is studied. It is shown that the electrons changes their motion from randomness (in equilibrium) to streamlined one (in non-equilibrium) when high electric field is applied. The intrinsic velocity is discussed in non-parabolic semiconducting limits considering the nondegenerate and degenerate situations. The results obtained are significant in extracting carrier transport properties from experimental data on CNTs and in understanding the fundamental processes controlling the charge transport in nanoscale devices.

Chek, Desmond C. Y.; Hashim, Abdul Manaf [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Tan, Michael Loong Peng [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Arora, Vijay K. [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA 18766 (United States)

2011-05-25T23:59:59.000Z

215

Velocity Autocorrelation Functions and Diffusion of Dusty Plasma  

SciTech Connect

The velocity autocorrelation functions and square displacements were calculated on the basis of experimental data obtained on experimental setup with dc discharge. Computer simulation of the system of dust particles by the method of the Langevin dynamics was performed. The comparisons of experimental and theoretical results are given.

Ramazanov, T. S.; Dzhumagulova, K. N.; Daniyarov, T. T.; Dosbolayev, M. K.; Jumabekov, A. N. [IETP, al-Farabi Kazakh National University, 96a, Tole bi St., Almaty, 050012 (Kazakhstan)

2008-09-07T23:59:59.000Z

216

Velocity-Space Proton Diffusion in the Solar Wind Turbulence  

E-Print Network (OSTI)

We study a velocity-space quasilinear diffusion of the solar wind protons driven by oblique Alfven turbulence at proton kinetic scales. Turbulent fluctuations at these scales possess properties of kinetic Alfven waves (KAWs) that are efficient in Cherenkov resonant interactions. The proton diffusion proceeds via Cherenkov kicks and forms a quasilinear plateau - nonthermal proton tail in the velocity distribution function (VDF). The tails extend in velocity space along the mean magnetic field from 1 to (1.5-3) VA, depending on the spectral break position, turbulence amplitude at the spectral break, and spectral slope after the break. The most favorable conditions for the tail generation occur in the regions where the proton thermal and Alfven velocities are about the same, VTp/VA = 1. The estimated formation times are within 1-2 h for typical tails at 1 AU, which is much shorter than the solar wind expansion time. Our results suggest that the nonthermal proton tails, observed in-situ at all heliocentric distan...

Voitenko, Yuriy

2013-01-01T23:59:59.000Z

217

Seismic imaging for velocity and attenuation structure in geothermal fields  

DOE Green Energy (OSTI)

We have applied the attenuation inversion technique developed by Evans and Zucca (1988) to a seismic tomographic data set taken at Newberry Volcano by Achauer et al. (1988). Our preliminary results suggest that the interpretation of the velocity data by Achauer et al. that a magma chamber is present 3 km beneath the caldera is not confirmed by the attenuation data.

Zucca, J.J. (Lawrence Livermore National Lab., CA (USA)); Evans, J.R. (Geological Survey, Menlo Park, CA (USA))

1989-06-01T23:59:59.000Z

218

Effects of Velocity Shear in Advective Mixed-Layer Models  

Science Conference Proceedings (OSTI)

A general multidimensional model of the upper mixed layer of oceans and lakes is presented. The density profile is approximated as uniform over the depth of the layer. Such an assumption is not made for the distribution of the horizontal velocity ...

Will P. M. de Ruijter

1983-09-01T23:59:59.000Z

219

Measurement of turbulent wind velocities using a rotating boom apparatus  

DOE Green Energy (OSTI)

The present report covers both the development of a rotating-boom facility and the evaluation of the spectral energy of the turbulence measured relative to the rotating boom. The rotating boom is composed of a helicopter blade driven through a pulley speed reducer by a variable speed motor. The boom is mounted on a semiportable tower that can be raised to provide various ratios of hub height to rotor diameter. The boom can be mounted to rotate in either the vertical or horizontal plane. Probes that measure the three components of turbulence can be mounted at any location along the radius of the boom. Special hot-film sensors measured two components of the turbulence at a point directly in front of the rotating blade. By using the probe rotated 90/sup 0/ about its axis, the third turbulent velocity component was measured. Evaluation of the spectral energy distributions for the three components of velocity indicates a large concentration of energy at the rotational frequency. At frequencies slightly below the rotational frequency, the spectral energy is greatly reduced over that measured for the nonrotating case measurements. Peaks in the energy at frequencies that are multiples of the rotation frequency were also observed. We conclude that the rotating boom apparatus is suitable and ready to be used in experiments for developing and testing sensors for rotational measurement of wind velocity from wind turbine rotors. It also can be used to accurately measure turbulent wind for testing theories of rotationally sampled wind velocity.

Sandborn, V.A.; Connell, J.R.

1984-04-01T23:59:59.000Z

220

A fixed complexity velocity estimation method for mobile MIMO users  

Science Conference Proceedings (OSTI)

To estimate speed of a moving user transmitting data over a Single Input Single Output (SISO) Rayleigh fading channels, many Autocorrelation function (ACF) based schemes have been presented in literature [2-7]. Recently, it was shown that in a Multiple ... Keywords: autocorrelation function, complexity reduction, correlated MIMO channels, velocity estimation

Salman A. Khan

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

The relativistic velocity addition law optimizes a forecast gambler's profit  

E-Print Network (OSTI)

We extend the projective covariant bookmaker's bets model to the forecasting gamblers case. The probability of correctness of forecasts shifts probabilities of branching. The formula for the shift of probabilities leads to the velocity addition rule of the special theory of relativity. In the absence of information about bookmaker's wagers the stochastic logarithmic rates completely determines the optimal stakes of forecast gambler.

Piotrowski, Edward W

2007-01-01T23:59:59.000Z

222

The Cartesian Diver: A Self-Profiling Lagrangian Velocity Recorder  

Science Conference Proceedings (OSTI)

The Cartesian diver is an autonomous velocity profiler capable of operating to 1 km depth in the ocean. It has a self-controlled buoyancy changer which is used to control the direction of profiling. The buoyancy changer has two states, full ...

T. F. Duda; C. S. Cox; T. K. Deaton

1988-02-01T23:59:59.000Z

223

Particle velocity measurements of the reaction zone in nitromethane  

DOE Green Energy (OSTI)

The detonation reaction-zone length in neat, deuterated, and chemically sensitized nitromethane (NM) has been measured by using several different laser-based velocity interferometry systems. The experiments involved measuring the particle velocity history at a NM/PMMA (polymethylmethacrylate) window interface during the time a detonation in the NM interacted with the interface. Initially, Fabry-Perot interferometry was used, but, because of low time resolution (>5 ns), several different configurations of VISAR interferometry were subsequently used. Early work was done with VISARs with a time resolution of about 3 ns. By making changes to the recording system, we were able to improve this to {approx}1 ns. Profiles measured at the NM/PMMA interface agree with the ZND theory, in that a spike ({approx}2.45 mm/{micro}s) is measured that is consistent with an extrapolated reactant NM Hugoniot matched to the PMMA window. The spike is rather sharp, followed by a rapid drop in particle velocity over a time of 5 to 10 ns; this is evidence of early fast reactions. Over about 50 ns, a much slower particle velocity decrease occurs to the assumed CJ condition - indicating a total reaction zone length of {approx}300 {micro}m. When the NM is chemically changed, such as replacing the hydrogen atoms with deuterium or chemically sensitizing with a base, some changes are observed in the early part of the reaction zone.

Sheffield, S. A. (Stephen A.); Engelke, R. P. (Raymond P.); Alcon, R. R. (Robert R.); Gustavsen, R. L. (Richard L.); Robbins, D. L. (David L.); Stahl, D. B. (David B.); Stacy, H. L. (Howard L.); Whitehead, M. (Michael)

2002-01-01T23:59:59.000Z

224

Velocity and Stress in the Deep-Ocean Boundary Layer  

Science Conference Proceedings (OSTI)

In order to predict the response of deep ocean sediments to the near-bottom currents, accurate estimates of the near-bottom velocity and the boundary shear stress are necessary. Because of the unsteady nature of deep ocean currents, dynamic ...

S. R. McLean; J. Yean

1987-09-01T23:59:59.000Z

225

Deep ADCP Velocity Measurements in the Gulf Stream  

Science Conference Proceedings (OSTI)

This paper presents observations of the velocity structure from two transects across a Gulf Stream meander near 37°N, 68°W. Data were collected with a vessel-mounted 75-kHz acoustic Doppler current profiler (ADCP) to a depth of about 700 m. The ...

A. V. Berezutskii; S. E. Maximov; V. E. Sklyarov; R. L. Gordon

1991-12-01T23:59:59.000Z

226

Low Velocity Sphere Impact of a Soda Lime Silicate Glass  

SciTech Connect

This report summarizes TARDEC-sponsored work at Oak Ridge National Laboratory (ORNL) during the FY11 involving low velocity (< 30 m/s or < 65 mph) ball impact testing of Starphire soda lime silicate glass. The intent was to better understand low velocity impact response in the Starphire for sphere densities that bracketed that of rock. Five sphere materials were used: borosilicate glass, soda-lime silicate glass, steel, silicon nitride, and alumina. A gas gun was fabricated to produce controlled velocity delivery of the spheres against Starphire tile targets. Minimum impact velocities to initiate fracture in the Starphire were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the any of the five sphere-Starphire-target combinations. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Frictional effects contribute to fracture initiation. (2) Spheres with a lower elastic modulus require less force to initiate fracture in the Starphire than spheres with a higher elastic modulus. (3) Contact-induced fracture did not initiate in the Starphire SLS for impact kinetic energies < 150 mJ. Fracture sometimes initiated or kinetic energies between {approx} 150-1100 mJ; however, it tended to occur when lower elastic modulus spheres were impacting it. Contact-induced fracture would always occur for impact energies > 1100 mJ. (4) The force necessary to initiate contact-induced fracture is higher under dynamic or impact conditions than it is under quasi-static indentation conditions. (5) Among the five used sphere materials, silicon nitride was the closest match to 'rock' in terms of both density and (probably) elastic modulus.

Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL; Morrissey, Timothy G [ORNL; Vuono, Daniel J [ORNL

2011-10-01T23:59:59.000Z

227

Generalization of Child-Langmuir Law for Non-Zero Injection Velocities in a Planar Diode  

E-Print Network (OSTI)

The Child-Langmuir law relates the voltage applied across a planar diode to the saturation value J_CL of current density that can be transmitted through it in case the injection velocity of electrons into the diode is zero. The Child-Langmuir current density J_CL is, at the same time, (i) the maximum current density that can be transmitted through a planar diode, (ii) the current density below which the flow is steady and unidirectional in the long time limit and (iii) the average transmitted current density for {\\em any} value of injected current density above J_CL. Existing generalizations of Child-Langmuir law to non-zero velocities of injection are based on the characteristics (i) and (ii) of J_CL. This paper generalizes the law to non-zero velocities of injection based on the characteristic (iii) by deriving an analytical expression for the saturation value of current density. The analytical expression for the saturation current density is found to be well supported by numerical computations. A reason behind preferring the saturation property of the Child-Langmuir current density as the basis for its generalization is the importance of that property in numerical simulations of high current diode devices.

R. R. Puri; Debabrata Biswas; Raghwendra Kumar

2004-11-19T23:59:59.000Z

228

PROBING THE HALO FROM THE SOLAR VICINITY TO THE OUTER GALAXY: CONNECTING STARS IN LOCAL VELOCITY STRUCTURES TO LARGE-SCALE CLOUDS  

Science Conference Proceedings (OSTI)

This paper presents the first potential connections made between two local features in velocity space found in a survey of M giant stars and stellar spatial inhomogeneities on global scales. Comparison to cosmological, chemodynamical stellar halo models confirms that the M giant population is particularly sensitive to rare, recent and massive accretion events. These events can give rise to locally observed velocity sequences-each made from a small fraction of debris from a massive progenitor, passing at high velocity through the survey volume, near the pericenter of the eccentric orbit of the system. The majority of the debris is found in much larger structures, whose morphologies are more cloud-like than stream-like and which lie at the orbital apocenters. Adopting this interpretation, the full-space motions represented by the observed M giant velocity features are derived under the assumption that the members within each sequence share a common space velocity. Orbit integrations are then used to trace the past and future trajectories of these stars across the sky revealing plausible associations with large, previously discovered, cloud-like structures. The connections made between nearby velocity structures and these distant clouds represent preliminary steps toward developing coherent maps of such giant debris systems. These maps promise to provide new insights into the origin of debris clouds, new probes of Galactic history and structure, and new constraints on the high-velocity tails of the local dark matter distribution that are essential for interpreting direct dark matter particle detection experiments.

Johnston, Kathryn V.; Sheffield, Allyson A. [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-0818 (United States); Sharma, Sanjib [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Rocha-Pinto, Helio J., E-mail: kvj@astro.columbia.edu [Observatorio do Valongo, Universidade Federal do Rio de Janeiro (Brazil)

2012-11-20T23:59:59.000Z

229

Low Velocity Sphere Impact of a Soda Lime Silicate Glass  

Science Conference Proceedings (OSTI)

This report summarizes TARDEC-sponsored work at Oak Ridge National Laboratory (ORNL) during the FY11 involving low velocity (energy of impact and the elastic property mismatch between the any of the five sphere-Starphire-target combinations. The primary observations from this low velocity (energies energies between {approx} 150-1100 mJ; however, it tended to occur when lower elastic modulus spheres were impacting it. Contact-induced fracture would always occur for impact energies > 1100 mJ. (4) The force necessary to initiate contact-induced fracture is higher under dynamic or impact conditions than it is under quasi-static indentation conditions. (5) Among the five used sphere materials, silicon nitride was the closest match to 'rock' in terms of both density and (probably) elastic modulus.

Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL; Morrissey, Timothy G [ORNL; Vuono, Daniel J [ORNL

2011-10-01T23:59:59.000Z

230

Velocity and density spectra of the Small Magellanic Cloud  

E-Print Network (OSTI)

This paper reports results on the statistical analysis of HI turbulence in the Small Magellanic Cloud (SMC). We use 21 cm channel maps, obtained with the Australia Telescope Compact Array and the Parkes telescope, and analyze the spectrum of observed intensity fluctuations as a function of the velocity slice thickness. We confirm predictions by Lazarian & Pogosyan (2000) on the change of the power law index and establish the spectra of 3-D density and velocity. The obtained spectral indices, -3.3 and -3.4, are slightly more shallow than the predictions for the Kolmogorov spectrum. This contrasts to the predictions for the shock-type spectra that are steeper than the Kolmogorov one. The nature of the energy injection in the SMC is unclear as no distinct energy injection scales are observed up to the entire scale of the SMC.

S. Stanimirovi?; A. Lazarian

2001-02-11T23:59:59.000Z

231

The AMS-RICH velocity and charge reconstruction  

E-Print Network (OSTI)

The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.

F. Barao; M. Aguilar-Benitez; L. Arruda; B. Baret; A. Barrau; G. Barreira; E. Belmont; J. Berdugo; J. Borges; M. Buenerd; D. Casadei; J. Casaus; E. Cortina; M. Costado; D. Crespo; C. Delgado; C. Diaz; L. Derome; P. Goncalves; R. Garcia-Lopez; C. de la Guia; A. Herrero; E. Lanciotti; G. Laurenti; A. Malinin; C. Mana; J. Marin; M. Mangin-Brinet; G. Martinez; A. Menchaca-Rocha; C. Palomares; R. Pereira; M. Pimenta; A. Putze; Y. Sallaz-Damaz; E. S. Seo; I. Sevilla; A. Torrento; M. Vargas-Trevino; O. Veziant

2007-09-13T23:59:59.000Z

232

Superluminal group velocity through near-maximal neutrino oscillations  

E-Print Network (OSTI)

Recently it was suggested that the observation of superluminal neutrinos by the OPERA collaboration may be due to group velocity effects resulting from close-to-maximal oscillation between neutrino mass eigenstates, in analogy to known effects in optics. We show that superluminal propagation does occur through this effect for a series of very narrow energy ranges, but this phenomenum cannot explain the OPERA measurement.

Tim R. Morris

2011-10-11T23:59:59.000Z

233

Generation of Ultrahigh-Velocity Ionizing Shocks with Petawatt-Class Laser Pulses  

Science Conference Proceedings (OSTI)

Ultrahigh-velocity shock waves (approx10 000 km/s or 0.03c) are generated by focusing a 350-TW laser pulse into low-density helium gas. The collisionless ultrahigh-Mach-number electrostatic shock propagates from the plasma into the surrounding gas, ionizing gas as it becomes collisional. The shock undergoes a corrugation instability due to propagation of the ionizing shock within the gas (the Dyakov-Kontorovich instability). This system may be relevant to the study of very high-Mach-number ionizing shocks in astrophysical situations.

Nilson, P. M.; Mangles, S. P. D.; Willingale, L.; Kaluza, M. C.; Thomas, A. G. R.; Najmudin, Z.; Evans, R. G.; Dangor, A. E.; Krushelnick, K. [Department of Physics, Imperial College, London SW7 2AZ United Kingdom (United Kingdom); Tatarakis, M.; Lancaster, K. L. [Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Clarke, R. J. [CLF, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon., OX11 0QX United Kingdom (United Kingdom); Karsch, S. [Max-Planck Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748, Garching (Germany); Schreiber, J. [Max-Planck Institut fuer Quantenoptik, Hans-Kopfermann-Strasse, D-85748, Garching (Germany); Ludwig-Maximilians-Universistaet Munchen, Am Coulombwall, D-85748, Garching (Germany)

2009-12-18T23:59:59.000Z

234

Shear wave velocities from noise correlation at local scale  

Science Conference Proceedings (OSTI)

Cross correlations of ambient seismic noise recordings have been studied to infer shear seismic velocities with depth. Experiments have been done in the crowded and noisy historical centre of Napoli over inter-station distances from 50 m to about 400 m, whereas active seismic spreadings are prohibitive, even for just one receiver. Group velocity dispersion curves have been extracted with FTAN method from the noise cross correlations and then the non linear inversion of them has resulted in Vs profiles with depth. The information of near by stratigraphies and the range of Vs variability for samples of Neapolitan soils and rocks confirms the validity of results obtained with our expeditious procedure. Moreover, the good comparison of noise H/V frequency of the first main peak with 1D and 2D spectral amplifications encourages to continue experiments of noise cross-correlation. If confirmed in other geological settings, the proposed approach could reveal a low cost methodology to obtain reliable and detailed Vs velocity profiles.

De Nisco, G.; Nunziata, C. [Dipartimento di Scienze della Terra, Univ. Napoli Federico II (Italy); Vaccari, F. [Dipartimento di Scienze della Terra, Univ. Trieste (Italy); Panza, G. F. [Dipartimento di Scienze della Terra, Univ. Trieste (Italy); The Abdus Salam International Center for Theoretical Physics, ESP-SAND Group, Trieste (Italy)

2008-07-08T23:59:59.000Z

235

Fermi velocity renormalization and the excitonic insulator in graphene  

E-Print Network (OSTI)

We compute the Fermi velocity of the Dirac quasiparticles in clean graphene at the charge neutrality point for strong Coulomb coupling alpha_g. We perform a Lattice Monte Carlo calculation within the low-energy Dirac theory, which includes an instantaneous, long-range Coulomb interaction. This method is non-perturbative and takes full account of quantum fluctuations. We find a finite renormalized Fermi velocity v_FR > v_F, where v_F = c/300. We introduce the critical Fermi velocity renormalization v_c = v_FR(alpha_gc)/v_F, where alpha_gc is the critical coupling for the semimetal-insulator transition due to excitonic pair formation. We compare our results with empirical studies of interaction-induced spectral changes in graphene. We find v_c = 3.3, which should be contrasted with v_FR/v_F = 2 - 3 for ultra-clean suspended graphene and v_FR/v_F = 1.2 for graphene on a boron nitride substrate. Our results are consistent with the non-observation of insulating states in suspended graphene in the absence of an external magnetic field. We also discuss the dynamical critical exponent z.

Joaquín E. Drut; Timo A. Lähde

2013-04-05T23:59:59.000Z

236

Low Velocity Sphere Impact of a Borosilicate Glass  

SciTech Connect

This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (< 30 m/s or < 65 mph) ball impact testing of Borofloat borosilicate glass, and is a follow-up to a similar study completed by the authors on Starphire soda-lime silicate glass last year. The response of the borosilicate glass to impact testing at different angles was also studied. The Borofloat glass was supplied by the US Army Research Laboratory and its tin-side was impacted or indented. The intent was to better understand low velocity impact response in the Borofloat. Seven sphere materials were used whose densities bracket that of rock: borosilicate glass, soda-lime silicate glass, silicon nitride, aluminum oxide, zirconium oxide, carbon steel, and a chrome steel. A gas gun or a ball-drop test setup was used to produce controlled velocity delivery of the spheres against the glass tile targets. Minimum impact velocities to initiate fracture in the Borofloat were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the seven sphere-Borofloat-target combinations. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) BS glass responded similarly to soda-lime silicate glass when spherically indented but quite differently under sphere impact conditions; (2) Frictional effects contributed to fracture initiation in BS glass when it spherically indented. This effect was also observed with soda-lime silicate glass; (3) The force necessary to initiate fracture in BS glass under spherical impact decreases with increasing elastic modulus of the sphere material. This trend is opposite to what was observed with soda-lime silicate glass. Friction cannot explain this trend and the authors do not have a legitimate explanation for it yet; (4) The force necessary to initiate contact-induced fracture is higher under dynamic conditions than under quasi-static conditions. That difference decreases with increasing elastic modulus mismatch between the sphere material and borosilicate This trend was opposite in soda-lime silicate glass; (5) Fracture in borosilicate glass occurs at lower velocities (i.e., easier) at 24{sup o} than at 0{sup o} (orthogonal) and 46{sup o} of impact for the same probability of failure. Though not analyzed yet, this suggests that a convolution of kinetic energy and friction is contributing to that trend; (6) There is a subtle indication there was intra-tile differences in spherical indentation RCIF. This likely is not a material property nor exclusive to borosilicate glass, rather, it is a statistical response of a combination of local, surface-located flaw and imposed tensile stress. Understanding of the surface flaw population and flaw positioning can likely enable prediction of spherical indentation RCIF; and (7) Contact-induced fracture did not initiate in the Borofloat BS for impact kinetic energies up to {approx} 20 mJ. For kinetic energies between {approx} 20-150 mJ, fracture sometimes initiated. Contact-induced fracture would always occur for impact energies > 150 mJ. The energy values, and their boundaries, were much lower for BS glass than they were for soda-lime silicate glass.

Morrissey, Timothy G [ORNL; Ferber, Mattison K [ORNL; Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL

2012-05-01T23:59:59.000Z

237

VELOCITY SELECTOR METHOD FOR THE SEPARATION OF ISOTOPES  

DOE Patents (OSTI)

A velocity selector apparatus is described for separating and collecting an enriched fraction of the isotope of a particular element. The invention has the advantage over conventional mass spectrometers in that a magnetic field is not used, doing away with the attendant problems of magnetic field variation. The apparatus separates the isotopes by selectively accelerating the ionized constituents present in a beam of the polyisotopic substance that are of uniform kinetic energy, the acceleration being applied intermittently and at spaced points along the beam and in a direction normal to the direction of the propagation of the uniform energy beam whereby a transverse displacement of the isotopic constituents of different mass is obtained.

Britten, R.J.

1957-12-31T23:59:59.000Z

238

Velocity shear-induced effects on electrostatic ion perturbations  

Science Conference Proceedings (OSTI)

Linear evolution of electrostatic perturbations in an unmagnetized electron{endash}ion plasma shear flow is studied. New physical effects, arising due to the non-normality of linear dynamics are disclosed. A new class of {ital nonperiodic collective mode} with vortical motion of ions, characterized by intense energy exchange with the mean flow, is found. It is also shown that the velocity shear induces extraction of the mean flow energy by ion-sound waves and that during the shear-induced evolution the ion-sound waves turn eventually into ion plasma oscillations. {copyright} {ital 1997 American Institute of Physics.}

Rogava, A.D. [Department of Physics, Tbilisi State University, and Department of Theoretical Astrophysics, Abastumani Astrophysical Observatory, Tbilisi, Republic of (Georgia)] [Department of Physics, Tbilisi State University, and Department of Theoretical Astrophysics, Abastumani Astrophysical Observatory, Tbilisi, Republic of (Georgia); Chagelishvili, G.D. [Department of Theoretical Astrophysics, Abastumani Astrophysical Observatory, Tbilisi, Republic of (Georgia)] [Department of Theoretical Astrophysics, Abastumani Astrophysical Observatory, Tbilisi, Republic of (Georgia); [Department of Cosmogeophysics, Space Research Institute, Moscow (Russia); Berezhiani, V.I. [Department of Plasma Physics, Institute of Physics, Tbilisi, Republic of (Georgia)] [Department of Plasma Physics, Institute of Physics, Tbilisi, Republic of (Georgia)

1997-12-01T23:59:59.000Z

239

Determination of sputtered atom densities and velocities via simulation  

Science Conference Proceedings (OSTI)

Transport of sputtered atoms in a plasma sputtering unit is simulated using two known elastic collision models. The methods of studying the collision of two atoms are isotropic random scattering angle in the center of mass frame and the so-called center to center collision model in which the impact parameter is ignored and the two particles collide such as two material points. The obtained results for the density and velocity of sputtered atoms in both models are compared with some experimental reports. This investigation shows that the copper and argon atoms present pointlike behavior in the collision process.

Khorram, S.; Sobhanian, S. [Faculty of Physics, University of Tabriz, Tabriz, 51666 (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz, 51666 (Iran, Islamic Republic of); Naghshara, H. [Faculty of Physics, University of Tabriz, Tabriz, 51666 (Iran, Islamic Republic of)

2011-04-01T23:59:59.000Z

240

Method and apparatus for measuring flow velocity using matched filters  

DOE Patents (OSTI)

An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow is disclosed. Signals arising from flow noise disturbance are extracted from the flow, at upstream and downstream locations. The signals are processed through pairs of matched filters which are matched to the flow disturbance frequency characteristics of the phase flow component to be measured. The processed signals are then cross-correlated to determine the transit delay time of the phase flow component between sensing positions.

Raptis, A.C.

1981-07-17T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


241

Velocity Profiles in a Cylindrical Liquid Jet by Reconstructed Velocimetry  

E-Print Network (OSTI)

in such a way that the jet boundaries appeared sharply focused. The Newtonian liquid used in all the experiments was a mixture of 74.7% glycerol (99.9% pure) with 25.3% tri- distilled water (weight percentage). Its measured properties were: density ? = 1250... dynamics theory (or numerical simulations) for un-wetted nozzles, but to explore the effects of nozzle wetting on the velocity profiles. It is well-known that nozzle face wetting slightly enlarges the jet diameter for some distance down- stream from...

Castrejon-Pita, J.R.; Hoath, S.D.; Hutchings, I.M.

2012-01-01T23:59:59.000Z

242

Thermalization in harmonic particle chains with velocity flips  

E-Print Network (OSTI)

We propose a new mathematical tool for the study of transport properties of models for lattice vibrations in crystalline solids. By replication of dynamical degrees of freedom, we aim at a new dynamical system where the "local" dynamics can be isolated and solved independently from the "global" evolution. The replication procedure is very generic but not unique as it depends on how the original dynamics are split between the local and global dynamics. As an explicit example, we apply the scheme to study thermalization of the pinned harmonic chain with velocity flips. We improve on the previous results about this system by showing that after a relatively short time period the average kinetic temperature profile satisfies the dynamic Fourier's law in a local microscopic sense without assuming that the initial data is close to a local equilibrium state. The bounds derived here prove that the above thermalization period is at most of the order L^(2/3), where L denotes the number of particles in the chain. In particular, even before the diffusive time scale Fourier's law becomes a valid approximation of the evolution of the kinetic temperature profile. As a second application of the dynamic replica method, we also briefly discuss replacing the velocity flips by an anharmonic onsite potential.

Jani Lukkarinen

2013-08-22T23:59:59.000Z

243

Low Velocity Sphere Impact of a Borosilicate Glass  

Science Conference Proceedings (OSTI)

This report summarizes US Army TARDEC sponsored work at Oak Ridge National Laboratory (ORNL) involving low velocity (energy of impact and the elastic property mismatch between the seven sphere-Borofloat-target combinations. The primary observations from this low velocity (energy and friction is contributing to that trend; (6) There is a subtle indication there was intra-tile differences in spherical indentation RCIF. This likely is not a material property nor exclusive to borosilicate glass, rather, it is a statistical response of a combination of local, surface-located flaw and imposed tensile stress. Understanding of the surface flaw population and flaw positioning can likely enable prediction of spherical indentation RCIF; and (7) Contact-induced fracture did not initiate in the Borofloat BS for impact kinetic energies up to {approx} 20 mJ. For kinetic energies between {approx} 20-150 mJ, fracture sometimes initiated. Contact-induced fracture would always occur for impact energies > 150 mJ. The energy values, and their boundaries, were much lower for BS glass than they were for soda-lime silicate glass.

Morrissey, Timothy G [ORNL; Ferber, Mattison K [ORNL; Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL

2012-05-01T23:59:59.000Z

244

An Optical Array Instrument for Shape and Fall Velocity Measurements of Hydrometeors  

Science Conference Proceedings (OSTI)

A ground-based optical array instrument for the measurement of shapes, sizes, and fall velocities of freely falling hydrometeors is presented. The instrument, the Hydrometeor Velocity and Shape Detector (HVSD), is designed to accurately measure ...

E. Barthazy; S. Göke; R. Schefold; D. Högl

2004-09-01T23:59:59.000Z

245

Combining Inverted Echo Sounder and Horizontal Electric Field Recorder Measurements to Obtain Absolute Velocity Profiles  

Science Conference Proceedings (OSTI)

Profiles of absolute velocity are difficult to obtain in the ocean, especially over long periods of time at the same location. This paper presents a method of estimating full water column absolute horizontal velocity profiles as a function of ...

Christopher S. Meinen; Douglas S. Luther; D. Randolph Watts; Karen L. Tracey; Alan D. Chave; James Richman

2002-10-01T23:59:59.000Z

246

A Comparison of Vertical Velocity in Cirrus Obtained from Aircraft and Lidar Divergence Measurements during FIRE  

Science Conference Proceedings (OSTI)

Techniques are presented to obtain vertical velocity in cirrus clouds from in situ aircraft lateral wind measurements and from ground-based remote Doppler lidar measurements. In general, direct measurements of absolute vertical velocity w from ...

I. Gultepe; A. J. Heymsfield; D. H. Lenschow

1990-02-01T23:59:59.000Z

247

Dependence of Turbulent and Mesoscale Velocity Variances on Scale and Stability  

Science Conference Proceedings (OSTI)

The scale dependence of velocity variances is studied using data collected from a grassland site, a heather site, and four forested sites. The dependence of velocity variances on averaging time, used to define the fluctuation quantities, is ...

L. Mahrt; Erin Moore; Dean Vickers; N. O. Jensen

2001-03-01T23:59:59.000Z

248

Peak ground velocity evaluation by artificial neural network for west america region  

Science Conference Proceedings (OSTI)

With the Peak Ground Velocity 283 records in three dimensions, the velocity attenuation relationship with distance was discussed by neural network in this paper. The earthquake magnitude, epicenter distance, site intensity and site condition were considered ...

Ben-yu Liu; Liao-yuan Ye; Mei-ling Xiao; Sheng Miao

2006-10-01T23:59:59.000Z

249

Non-Gaussian Velocity Probability Density Functions: An Altimetric Perspective of the Mediterranean Sea  

Science Conference Proceedings (OSTI)

Velocity probability density functions (PDFs) are a key tool to study complex flows and are of great importance to model particle dispersion. The PDFs of geostrophic velocities derived from sea level anomalies maps for the Mediterranean Sea have ...

Jordi Isern-Fontanet; Emilio García-Ladona; Jordi Font; Antonio García-Olivares

2006-11-01T23:59:59.000Z

250

Effects of Radar Proximity on Single-Doppler Velocity Signatures of Axisymmetric Rotation and Divergence  

Science Conference Proceedings (OSTI)

Geometrical and mathematical relationships are developed to explain the variation with radar range of idealized single-Doppler velocity patterns of axisymmetric rotation and divergence regions. The velocity patterns become distorted as they ...

Vincent T. Wood; Rodger A. Brown

1992-12-01T23:59:59.000Z

251

An Intercomparison Study Using Electromagnetic Three-Component Turbulent Velocity Probes  

Science Conference Proceedings (OSTI)

An intercomparison study was performed with four Russian-made, electromagnetic probes capable of measuring three components of oceanic turbulent velocities and two single-axis velocity sensors familiar to western scientists, namely, a hot-film ...

David Y. Lai; Vadim T. Paka; Donald P. Delisi; Anatoli V. Arjannikov; Sergei A. Khanaev

2000-07-01T23:59:59.000Z

252

A QUANTUM MECHANICAL APPROACH TO THE VELOCITY OF DISLOCATIONS IN ICE  

E-Print Network (OSTI)

~, A. ~ Higashi, A. , Physics of Ice, edited by N. Riehl, B.THE VELOCITY OF DISLOCATIONS IN ICE RECEIVED LAWRENCE A. R.the velocity of dislocations in ice ref. (3,4) with which we

Forouhi, A.R.

2011-01-01T23:59:59.000Z

253

Computation of the Streamfunction and Velocity Potential for Limited and Irregular Domains  

Science Conference Proceedings (OSTI)

An algorithm is proposed for the computation of streamfunction and velocity potential from given horizontal velocity vectors based on solving a minimization problem. To guarantee the uniqueness of the solution and computational reliability of the ...

Zhijin Li; Yi Chao; James C. McWilliams

2006-11-01T23:59:59.000Z

254

On the Structure of the Velocity Field over Progressive Mechanically-Generated Water Waves  

Science Conference Proceedings (OSTI)

The structure of the velocity field over a propagating wave of fixed frequency is examined. The vertical and horizontal velocities were measured in a transformed Eulerian wave-following frame of reference in a wind-wave research facility at ...

Yiannis Alex Papadimitrakis; En Yun Hsu; Robert L. Street

1984-12-01T23:59:59.000Z

255

Robust Estimations of Current Velocities with Four-Beam Broadband ADCPs  

Science Conference Proceedings (OSTI)

An extended explanation of the hypothesis and equations traditionally used to transform between four-beam ADCP radial beam velocities and current velocity components is presented. This explanation includes a dissertation about the meaning of the ...

M. Gilcoto; Emlyn Jones; Luis Fariña-Busto

2009-12-01T23:59:59.000Z

256

Terminal Velocities of Droplets and Crystals: Power Laws with Continuous Parameters over the Size Spectrum  

Science Conference Proceedings (OSTI)

This paper presents a unified treatment of cloud particle fall velocities for both liquid and crystalline cloud particles over the entire size range observed in the atmosphere. The fall velocity representation is formulated in terms of the Best (...

Vitaly I. Khvorostyanov; Judith A. Curry

2002-06-01T23:59:59.000Z

257

Distributions of Raindrop Sizes and Fall Velocities in a Semiarid Plateau Climate: Convective versus Stratiform Rains  

Science Conference Proceedings (OSTI)

Joint size and fall velocity distributions of raindrops were measured with a Particle Size and Velocity (PARSIVEL) precipitation particle disdrometer in a field experiment conducted during July and August 2007 at a semiarid continental site ...

Shengjie Niu; Xingcan Jia; Jianren Sang; Xiaoli Liu; Chunsong Lu; Yangang Liu

2010-04-01T23:59:59.000Z

258

Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography  

SciTech Connect

In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.

Brauchler, R.; Doetsch, J.; Dietrich, P.; Sauter, M.

2012-01-10T23:59:59.000Z

259

The Michigan/MIKE Fiber System Survey of Stellar Radial Velocities in Dwarf Spheroidal Galaxies: Acquisition and Reduction of Data  

E-Print Network (OSTI)

We introduce a stellar velocity survey of dwarf spheroidal galaxies, undertaken using the Michigan/MIKE Fiber System (MMFS) at the Magellan/Clay 6.5 m telescope at Las Campanas Observatory. As of 2006 November we have used MMFS to collect 6415 high-resolution (R= 20000-25000) spectra from 5180 stars in four dwarf spheroidal galaxies: Carina, Fornax, Sculptor and Sextans. Spectra sample the range 5140-5180 Angstroms, which includes the prominent magnesium triplet absorption feature. We measure radial velocity (RV) to a median precision of 2.0 km/s for stars as faint as V ~ 20.5. From the spectra we also are able to measure the strength of iron and magnesium absorption features using spectral indices that correlate with effective temperature, surface gravity and chemical abundance. Measurement of line strength allows us to identify interloping foreground stars independently of velocity, and to examine the metallicity distribution among dSph members. Here we present detailed descriptions of MMFS, our target selection and spectroscopic observations, the data reduction procedure, and error analysis. We compare our RV results to previously published measurements for individual stars. In some cases we find evidence for a mild, velocity-dependent offset between the RVs we measure using the magnesium triplet and previously published RV measurements derived from the infrared calcium triplet. In companion papers we will present the complete data sets and kinematic analyses of these new observations.

Matthew G. Walker; Mario Mateo; Edward W. Olszewski; Rebecca Bernstein; Bodhisattva Sen; Michael Woodroofe

2007-03-12T23:59:59.000Z

260

CHARACTERIZING THE GALACTIC WHITE DWARF BINARY POPULATION WITH SPARSELY SAMPLED RADIAL VELOCITY DATA  

Science Conference Proceedings (OSTI)

We present a method to characterize statistically the parameters of a detached binary sample-binary fraction, separation distribution, and mass-ratio distribution-using noisy radial velocity data with as few as two, randomly spaced, epochs per object. To do this, we analyze the distribution of {Delta}RV{sub max}, the maximum radial velocity difference between any two epochs for the same object. At low values, the core of this distribution is dominated by measurement errors, but for large enough samples there is a high-velocity tail that can effectively constrain the parameters of the binary population. We discuss our approach for the case of a population of detached white dwarf (WD) binaries with separations that are decaying via gravitational wave emission. We derive analytic expressions for the present-day distribution of separations, integrated over the star formation history of the Galaxy, for parameterized initial WD separation distributions at the end of the common-envelope phase. We use Monte Carlo techniques to produce grids of simulated {Delta}RV{sub max} distributions with specific binary population parameters, and the same sampling cadences and radial velocity errors as the observations, and we compare them to the real {Delta}RV{sub max} distribution to constrain the properties of the binary population. We illustrate the sensitivity of the method to both the model and observational parameters. In the particular case of binary WDs, every model population predicts a merger rate per star which can easily be compared to specific Type Ia supernova rates. In a companion paper, we apply the method to a sample of {approx}4000 WDs from the Sloan Digital Sky Survey. The binary fractions and separation distribution parameters allowed by the data indicate a rate of WD-WD mergers per unit stellar mass in the Galactic disk, {approx}1 Multiplication-Sign 10{sup -13} mergers yr{sup -1} M{sup -1}{sub Sun }, remarkably similar to the rate per unit mass of Type Ia supernovae in Milky Way like galaxies.

Maoz, Dan; Badenes, Carles [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Bickerton, Steven J., E-mail: maoz@astro.tau.ac.il, E-mail: badenes@pitt.edu, E-mail: bick@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544-1001 (United States)

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Dispersion in Neptune's Zonal Wind Velocities from NIR Keck AO Observations in July 2009  

E-Print Network (OSTI)

We report observations of Neptune made in H-(1.4-1.8 {\\mu}m) and K'-(2.0-2.4 {\\mu}m) bands on 14 and 16 July 2009 from the 10-m W.M. Keck II Telescope using the near-infrared camera NIRC2 coupled to the Adaptive Optics (AO) system. We track the positions of 54 bright atmospheric features over a few hours to derive their zonal and latitudinal velocities, and perform radiative transfer modeling to measure the cloud-top pressures of 50 features seen simultaneously in both bands. We observe one South Polar Feature (SPF) on 14 July and three SPFs on 16 July at ~65 deg S. The SPFs observed on both nights are different features, consistent with the high variability of Neptune's storms. There is significant dispersion in Neptune's zonal wind velocities about the smooth Voyager wind profile fit of Sromovsky et al., Icarus 105, 140 (1993), much greater than the upper limit we expect from vertical wind shear, with the largest dispersion seen at equatorial and southern mid-latitudes. Comparison of feature pressures vs. r...

Fitzpatrick, Patrick J; Luszcz-Cook, Statia; Wong, Michael H; Hammel, Heidi B

2013-01-01T23:59:59.000Z

262

On anomalous diffusion in a plasma in velocity space  

E-Print Network (OSTI)

The problem of anomalous diffusion in momentum space is considered for plasma-like systems on the basis of a new collision integral, which is appropriate for consideration of the probability transition function (PTF) with long tails in momentum space. The generalized Fokker-Planck equation for description of diffusion (in momentum space) of particles (ions, grains etc.) in a stochastic system of light particles (electrons, or electrons and ions, respectively) is applied to the evolution of the momentum particle distribution in a plasma. In a plasma the developed approach is also applicable to the diffusion of particles with an arbitrary mass relation, due to the small characteristic momentum transfer. The cases of an exponentially decreasing in momentum space (including the Boltzmann-like) kernel in the PT-function, as well as the more general kernels, which create the anomalous diffusion in velocity space due to the long tail in the PT-function, are considered. Effective friction and diffusion coefficients f...

Trigger, S A; van Heijst, G J F; Schram, P P J M; Sokolov, I M

2010-01-01T23:59:59.000Z

263

Detonation wave velocity and curvature of brass encased PBXN-111  

Science Conference Proceedings (OSTI)

Detonation velocities and wave front curvatures were measured for PBXN-111 charges encased in 5 mm thick brass tubes. In all the experiments (charge diameters from 19 to 47 mm) the brass case affected the detonation properties of PBXN-111. Steady detonation waves propagated in brass encased charges with diameters as small as 19 mm, which is about half of the unconfined failure diameter. The radii of curvature of the detonation waves at the center of the wave fronts ranged from 52 to 141 mm for charge diameters of 25 to 47 mm. The angles between the detonation wave fronts and the brass/charge interfaces were between 72 and 74 degrees. {copyright} {ital 1996 American Institute of Physics.}

Forbes, J.W.; Lemar, E.R. [Naval Surface Warfare Center, Indian Head Division, Silver Spring, Maryland 20903-5640 (United States)

1996-05-01T23:59:59.000Z

264

Acoustic-velocity measurements in materials using a regenerative method  

DOE Patents (OSTI)

Acoustic energy is propatated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

Laine, E.F.

1982-09-30T23:59:59.000Z

265

Acoustic velocity measurements in materials using a regenerative method  

DOE Patents (OSTI)

Acoustic energy is propagated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

Laine, Edwin F. (Alamo, CA)

1986-01-01T23:59:59.000Z

266

Measurements of Laminar Flame Velocity for Components of Natural Gas  

E-Print Network (OSTI)

This paper presents new experimental measurements of the laminar flame velocity of components of natural gas, methane, ethane, propane, and n?butane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been performed by the heat flux method using a newly built flat flame adiabatic burner at atmospheric pressure. The composition of the investigated air/hydrocarbon mixtures covers a wide range of equivalence ratios, from 0.6 to 2.1, for which it is possible to sufficiently stabilize the flame. Other measurements involving the enrichment of methane by hydrogen (up to 68%) and the enrichment of air by oxygen (oxycombustion techniques) were also performed. Both empirical correlations and a detailed chemical mechanism have been proposed, the predictions being satisfactorily compared with the newly obtained experimental data under a wide range of conditions.

Patricia Dirrenberger; Hervé Le Gall; Roda Bounaceur; Olivier Herbinet; Re Glaude; Er Konnov

2013-01-01T23:59:59.000Z

267

EVOLUTION OF QUIESCENT AND STAR-FORMING GALAXIES SINCE z {approx} 1.5 AS A FUNCTION OF THEIR VELOCITY DISPERSIONS  

SciTech Connect

We measure stellar masses and structural parameters for 5500 quiescent and 20,000 star-forming galaxies at 0.3 < z {<=} 1.5 in the Newfirm Medium Band Survey COSMOS and UKIDSS UDS fields. We combine these measurements to infer velocity dispersions and determine how the number density of galaxies at fixed inferred dispersion, or the velocity dispersion function (VDF), evolves with time for each population. We show that the number of galaxies with high velocity dispersions appears to be surprisingly stable with time, regardless of their star formation history. Furthermore, the overall VDF for star-forming galaxies is constant with redshift, extending down to the lowest velocity dispersions probed by this study. The only galaxy population showing strong evolution are quiescent galaxies with low inferred dispersions, whose number density increases by a factor of {approx}4 since z = 1.5. This buildup leads to an evolution in the quiescent fraction of galaxies such that the threshold dispersion above which quiescent galaxies dominate the counts moves to lower velocity dispersion with time. We show that our results are qualitatively consistent with a simple model in which star-forming galaxies quench and are added to the quiescent population. In order to compensate for the migration into the quiescent population, the velocity dispersions of star-forming galaxies must increase, with a rate that increases with dispersion.

Bezanson, Rachel; Van Dokkum, Pieter [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Franx, Marijn [Sterrewacht Leiden, Leiden University, NL-2300 RA Leiden (Netherlands)

2012-11-20T23:59:59.000Z

268

Force criterion prediction of damage for carbon/epoxy composite panels impacted by high velocity ice  

E-Print Network (OSTI)

system and class of layups (quasi-isotropic), delaminationunidirectional carbon/epoxy layup 6.15 mm thick. The FEAhaving quasi-isotropic layup [0/45/90/-45] s , [0/45/90/-45

Rhymer, Jennifer D.

2012-01-01T23:59:59.000Z

269

Extraction of the surface recombination velocity of passivated phosphorus-doped silicon emitters  

DOE Green Energy (OSTI)

An analytical procedure to extract the surface recombination velocity of the SiO{sub 2}/n type silicon interface, S{sub p}, from PCD measurements of emitter recombination currents is described. The analysis shows that the extracted values of S{sub p} are significantly affected by the assumed material parameters for highly doped silicon, t{sub p}, {mu}{sub p} and {Delta}E{sub g}{sup app}. Updated values for these parameters are used to obtain the dependence of S{sub p} on the phosphorus concentration, N{sub D}, using both previous and new experimental data. The new evidence supports the finding that S{sub p} increases strongly with N{sub D}.

Cuevas, A. [Australian National Univ., Canberra, CT (United States). Faculty of Engineering] [Australian National Univ., Canberra, CT (United States). Faculty of Engineering; Giroult-Matlakowski, G.; DuBols, C. [CNRS, Villeurbanne (France). Laboratoire de Physique de la Matiere] [CNRS, Villeurbanne (France). Laboratoire de Physique de la Matiere; Basore, P.A. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); King, R.R. [Siemens Solar Industries, Camarillo, CA (United States)] [Siemens Solar Industries, Camarillo, CA (United States)

1995-01-01T23:59:59.000Z

270

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles  

DOE Patents (OSTI)

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Benjamin, Robert F. (315 Rover Blvd., Los Alamos, NM 87544)

1987-01-01T23:59:59.000Z

271

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles  

DOE Patents (OSTI)

An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

Benjamin, R.F.

1983-10-18T23:59:59.000Z

272

Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles  

DOE Patents (OSTI)

An apparatus is disclosed for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously. 3 figs.

Benjamin, R.F.

1987-03-10T23:59:59.000Z

273

A line-imaging velocity interferometer technique for shock diagnostics without x-ray preheat limitation  

Science Conference Proceedings (OSTI)

A study was conducted with a line-imaging velocity interferometer on sandwich targets at the Shen Guang-III prototype laser facility in China, with the goal of eliminating the preheat effect. A sandwich target structure was used to reduce the x-ray preheat limitation (radiation temperature {approx}170 eV) in a radiative drive shock experiment. With a thick ablator, the preheat effect appeared before the shock arrived at the window. After adding a shield layer of high-Z material on the ablator, x-rays which penetrated the ablator were so weak that the blank-out effect could not be measured. This experiment indicates that the sandwich target may provide a valuable technique in experiments such as equation of state and shock timing for inertial confinement fusion studies.

Wang Feng; Peng Xiaoshi; Liu Shenye; Xu Tao; Mei Lusheng; Jiang Xiaohua; Ding Yongkun [Research Center of Laser Fusion, CAEP, P.O. Box 919-986, Mianyang 621900 (China)

2011-10-15T23:59:59.000Z

274

Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations  

Science Conference Proceedings (OSTI)

Laboratory (PNNL) conducted an extensive evaluation of the ability of three ultrasonic instruments to detect critical velocity for a broad range of simulated Hanford nuclear waste streams containing particles with mean particle sizes of >50 microns. Evaluations were perform using the pipe loop at the Process Development Laboratory – East (PDL-E) at PNNL that was designed and built to evaluate the pipeline plugging issue during slurry transfer operations at the Hanford Waste Treatment Plant. In 2011 the ability of the ultrasonic PulseEcho system to detect critical velocity continued to be evaluated using the PDL-E flow loop and new simulants containing high-density particles with a mean particle size of < 15 microns. The PDL-E flow loop was modified for the 2011 testing to include a new test section that contained 5-MHz and 10-MHz ultrasonic transducers non-invasively mounted to schedule 40 pipe. The test section also contained reference instrumentation to facilitate direct comparison of the real-time PulseEcho transducer responses with experimentally observed critical velocities. This paper presents the results from the 2011 PulseEcho evaluation using a variety of simulated Hanford nuclear waste streams that were selected to encompass the expected high-level waste feed properties.

Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Burns, Carolyn A.; Schonewill, Philip P.; Hopkins, Derek F.; Thien, Michael G.; Wooley, Theodore A.

2012-04-01T23:59:59.000Z

275

Nonlinear Landau damping and formation of Bernstein-Greene-Kruskal structures for plasmas with q-nonextensive velocity distributions  

SciTech Connect

In the past, long-time evolution of an initial perturbation in collisionless Maxwellian plasma (q = 1) has been simulated numerically. The controversy over the nonlinear fate of such electrostatic perturbations was resolved by Manfredi [Phys. Rev. Lett. 79, 2815-2818 (1997)] using long-time simulations up to t=1600{omega}{sub p}{sup -1}. The oscillations were found to continue indefinitely leading to Bernstein-Greene-Kruskal (BGK)-like phase-space vortices (from here on referred as 'BGK structures'). Using a newly developed, high resolution 1D Vlasov-Poisson solver based on piecewise-parabolic method (PPM) advection scheme, we investigate the nonlinear Landau damping in 1D plasma described by toy q-distributions for long times, up to t=3000{omega}{sub p}{sup -1}. We show that BGK structures are found only for a certain range of q-values around q = 1. Beyond this window, for the generic parameters, no BGK structures were observed. We observe that for values of q<1 where velocity distributions have long tails, strong Landau damping inhibits the formation of BGK structures. On the other hand, for q>1 where distribution has a sharp fall in velocity, the formation of BGK structures is rendered difficult due to high wave number damping imposed by the steep velocity profile, which had not been previously reported. Wherever relevant, we compare our results with past work.

Raghunathan, M. [Indian Institute of Science Education and Research (IISER), Pune 411021 (India); Ganesh, R. [Institute for Plasma Research, Gandhinagar 382428 (India)

2013-03-15T23:59:59.000Z

276

Longshore sediment transport rate calculated incorporating wave orbital velocity fluctuations  

E-Print Network (OSTI)

Laboratory experiments were performed to study and improve longshore sediment transport rate predictions. Measured total longshore transport in the laboratory was approximately three times greater for plunging breakers than spilling breakers. Three distinct zones of longshore transport were observed across the surf zone: the incipient breaker zone, inner surf zone, and swash zone. Transport at incipient breaking was influenced by breaker type; inner surf zone transport was dominated by wave height, independent of wave period; and swash zone transport was dependent on wave period. Selected predictive formulas to compute total load and distributed load transport were compared to laboratory and field data. Equations by Kamphuis (1991) and Madsen et al. (2003) gave consistent total sediment transport estimates for both laboratory and field data. Additionally, the CERC formula predicted measurements well if calibrated and applied to similar breaker types. Each of the distributed load models had shortcomings. The energetics model of Bodge and Dean (1987) was sensitive to fluctuations in energy dissipation and often predicted transport peaks that were not present in the data. The Watanabe (1992) equation, based on time-averaged bottom stress, predicted no transport at most laboratory locations. The Van Rijn (1993) model was comprehensive and required hydrodynamic, bedform, and sediment data. The model estimated the laboratory cross-shore distribution well, but greatly overestimated field transport. Seven models were developed in this study based on the principle that transported sediment is mobilized by the total shear stress acting on the bottom and transported by the current at that location. Shear stress, including the turbulent component, was calculated from the wave orbital velocity. Models 1 through 3 gave good estimates of the transport distribution, but underpredicted the transport peak near the plunging wave breakpoint. A suspension term was included in Models 4 through 7, which improved estimates near breaking for plunging breakers. Models 4, 5 and 7 also compared well to the field measurements. It was concluded that breaker type is an important variable in determining the amount of transport that occurs at a location. Lastly, inclusion of the turbulent component of the orbital velocity is vital in predictive sediment transport equations.

Smith, Ernest Ray

2006-08-01T23:59:59.000Z

277

Stochastic velocity motions and processes with random time  

E-Print Network (OSTI)

The aim of this paper is to analyze a class of random motions which models the motion of a particle on the real line with random velocity and subject to the action of the friction. The speed randomly changes when a Poissonian event occurs. We study the characteristic and the moment generating function of the position reached by the particle at time $t>0$. We are able to derive the explicit probability distributions in few cases for which discuss the connections with the random flights. The moments are also widely analyzed. For the random motions having an explicit density law, further interesting probabilistic interpretations emerge if we deal with them varying up a random time. Essentially, we consider two different type of random times, namely Bessel and Gamma times, which contain, as particular cases, some important probability distributions (e.g. Gaussian, Exponential). In particular, for the random processes built by means of these compositions, we derive the probability distributions fixed the number of...

De Gregorio, Alessandro

2009-01-01T23:59:59.000Z

278

Radiation Hydrodynamics Test Problems with Linear Velocity Profiles  

Science Conference Proceedings (OSTI)

As an extension of the works of Coggeshall and Ramsey, a class of analytic solutions to the radiation hydrodynamics equations is derived for code verification purposes. These solutions are valid under assumptions including diffusive radiation transport, a polytropic gas equation of state, constant conductivity, separable flow velocity proportional to the curvilinear radial coordinate, and divergence-free heat flux. In accordance with these assumptions, the derived solution class is mathematically invariant with respect to the presence of radiative heat conduction, and thus represents a solution to the compressible flow (Euler) equations with or without conduction terms included. With this solution class, a quantitative code verification study (using spatial convergence rates) is performed for the cell-centered, finite volume, Eulerian compressible flow code xRAGE developed at Los Alamos National Laboratory. Simulation results show near second order spatial convergence in all physical variables when using the hydrodynamics solver only, consistent with that solver's underlying order of accuracy. However, contrary to the mathematical properties of the solution class, when heat conduction algorithms are enabled the calculation does not converge to the analytic solution.

Hendon, Raymond C. [Los Alamos National Laboratory; Ramsey, Scott D. [Los Alamos National Laboratory

2012-08-22T23:59:59.000Z

279

Teleseismic evidence for a low-velocity body under the Coso geothermal area  

Open Energy Info (EERE)

Teleseismic evidence for a low-velocity body under the Coso geothermal area Teleseismic evidence for a low-velocity body under the Coso geothermal area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Teleseismic evidence for a low-velocity body under the Coso geothermal area Details Activities (1) Areas (1) Regions (0) Abstract: Teleseismic P wave arrivals were recorded by a dense array of seismograph stations located in the Coso geothermal area, California. The resulting pattern of relative residuals an area showing approximately 0.2-s excess travel time that migrates with changing source azimuth, suggesting that the area is the 'delay shadow' produced by a deep, low-velocity body. Inversion of the relative residual data for three-dimensional velocity structure determines the lateral variations in velocity to a depth of 22.5

280

Velocity distribution measurements in atomic beams generated using laser induced back-ablation  

E-Print Network (OSTI)

We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

Denning, A; Lee, S; Ammonson, M; Bergeson, S D

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Recommended Tritium Oxide Deposition Velocity For Use In Savannah River Site Safety Analyses  

SciTech Connect

This report documents the results of examining the deposition velocity of water to forests, the residence time of HTO in forests, and the relation between deposition velocity and residence time with specific consideration given to the topography and experimental work performed at SRS. A simple mechanistic model is used to obtain plausible deposition velocity and residence time values where experimental data are not available and recommendations are made for practical application in a safety analysis model.

Lee, P. L.; Murphy, C. E.; Viner, B. J.; Hunter, C. H.

2012-07-31T23:59:59.000Z

282

One-loop fluctuation-dissipation formula for bubble-wall velocity  

Science Conference Proceedings (OSTI)

The limiting bubble wall velocity during a first-order electroweak phase transition is of interest in scenarios for electroweak baryogenesis. Khlebnikov has recently proposed an interesting method for computing this velocity based on the fluctuation-dissipation theorem. It is demonstrated that at one-loop order this method is identical to simple, earlier techniques for computing the wall velocity based on computing the friction from particles reflecting off or transmitting through the wall in the ideal gas limit.

Arnold, P.

1993-06-01T23:59:59.000Z

283

RECOMMENDED TRITIUM OXIDE DEPOSITION VELOCITY FOR USE IN SAVANNAH RIVER SITE SAFETY ANALYSES  

Science Conference Proceedings (OSTI)

This report documents the results of examining the deposition velocity of water to forests, the residence time of HTO in forests, and the relation between deposition velocity and residence time with specific consideration given to the topography and experimental work performed at SRS. A simple mechanistic model is used to obtain plausible deposition velocity and residence time values where experimental data are not available and recommendations are made for practical application in a safety analysis model.

Lee, P.; Murphy, C.; Viner, B.; Jannik, T.; Hunter, C.; Moore, M.

2012-07-31T23:59:59.000Z

284

On the superficial gas velocity in deep gas-solids fluidized beds  

SciTech Connect

The superficial gas velocity is one of the key parameters used to determine the flow hydrodynamics in gas–solids fluidized beds. However, the superficial velocity varies with height in practice, and there is no consistent basis for its specification. Different approaches to determine the superficial gas velocity in a deep gas–solids system are shown to cause difficulties in developing models and in comparing predictions with experimental results. In addition, the reference conditions for superficial gas velocity are important in modeling of deep gas–solids systems where there is a considerable pressure drop.

Li, Tingwen; Grace, John; Shadle, Lawrence; Guenther, Chris

2012-11-15T23:59:59.000Z

285

On the Superficial Gas Velocity in Deep Gas-Solid Fluidized Beds  

Science Conference Proceedings (OSTI)

The superficial gas velocity is one of the key parameters used to determine the flow hydrodynamics in gas–solids fluidized beds. However, the superficial velocity varies with height in practice, and there is no consistent basis for its specification. Different approaches to determine the superficial gas velocity in a deep gas–solids system are shown to cause difficulties in developing models and in comparing predictions with experimental results. In addition, the reference conditions for superficial gas velocity are important in modeling of deep gas–solids systems where there is a considerable pressure drop.

Li, Tingwen; Grace, John; Shadle, Lawrence; Guenther, Chris

2011-11-15T23:59:59.000Z

286

Ion velocity distribution at the termination shock: 1-D PIC simulation  

Science Conference Proceedings (OSTI)

The Voyager 2 (V2) plasma observations of the proton temperature downstream of the quasi-perpendicular heliospheric termination shock (TS) showed that upstream thermal solar wind ions played little role in the shock dissipation mechanism and their downstream temperature is an order of magnitude smaller than predicted by MHD Rankine-Hugoniot conditions. While pickup ions (PUI) are generally expected to play an important role in energy dissipation at the shock, the details remain unclear. Here, one-dimensional (1-D) Particle-in-cell (PIC) code is used to examine kinetic properties and downstream velocity distribution functions of pickup ions (the hot supra-thermal component) and solar wind protons (SWs, the cold component) at the perpendicular heliospheric termination shock. The code treats the pickup ions self-consistently as a third component. Present results show that: (1) both of the incident SWs and PUIs can be separated into two parts: reflected (R) ions and directly transmitted (DT) ions, the energy gain of the R ions at the shock front is much larger than that of the DT ions; (2) the fraction of reflected SWs and their downstream temperature decrease with the relative percentage PUI%; (3) no matter how large the PUI% is, the downstream ion velocity distribution function always can be separated into three parts: 1. a high energy tail (i.e. the wings) dominated by the reflected PUIs, 2. a low energy core mainly contributed by the directly transmitted SWs, and 3. a middle energy part which is a complicated superposition of reflected SWs and directly transmitted PUIs. The significance of the presence of pickup ions on shock front micro-structure and nonstationarity is also discussed.

Lu Quanming; Yang Zhongwei; Lembege, Bertrand [CAS Key Laboratory of Basic Plasma Physics, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai 200136 (China); LATMOS-UVSQ-IPSL-CNRS, Guyancourt 78280 (France)

2012-11-20T23:59:59.000Z

287

Prediction of velocity and temperature profiles in thermally driven gravity currents applied to stratified thermal storage tanks  

DOE Green Energy (OSTI)

It has been demonstrated that one way of producing thin thermoclines in a chilled water thermal storage tank is by introducing the fluid in the form of a gravity current. Early in the flow the gravity current is controlled mainly by inertia and buoyancy forces, producing what is called the inertia-buoyancy (I-B) regime. Subsequently, the viscous force dominates inertia, and the flow is governed by viscous and buoyancy forces, resulting in the viscous-buoyancy (V-B) regime. In the work to be reported, vertical profiles of velocity and temperature in two-dimensional, thermally driven, constant inflow gravity currents were studied. This was done to provide a basis for understanding the initial stages of the formation of a thermocline. The gravity current was modelled with three regions, the head, the main body and the mixed region. In this analysis, the head was ignored and a laminar flow model was used to predict velocity and temperature profiles in the main body near the floor and in the mixed region above the main body and behind the head. Analytical and numerical models were developed for both regimes. Major features of the I-B regime temperature above the floor to an elevation roughly equal to the top of the inlet diffuser opening and a high gradient region above the top of the inlet opening. Velocity profiles in the I-B regime velocity profiles and also higher gradients above the top of the inlet opening than those in the V-B regime. 6 refs., 8 figs.

Nakos, J.T.; Wildin, M.W.

1988-01-01T23:59:59.000Z

288

High brightness electron accelerator  

DOE Patents (OSTI)

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity.

Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

1992-12-31T23:59:59.000Z

289

Vertical Velocities in a Thunderstorm Gust Front and Outflow  

Science Conference Proceedings (OSTI)

Continuous vertically pointing measurements of a thunderstorm outflow, including its gust front, were obtained with a Doppler radar near New Salem, North Dakota. The measurements provide a high-resolution depiction of the vertical structure of ...

Brooks E. Martner

1997-05-01T23:59:59.000Z

290

Zonal Velocity Structure and Transport in the Kuroshio Extension  

Science Conference Proceedings (OSTI)

The meridional structure of the zonal flow in the Kuroshio Extension is investigated using a combination of data from hydrographic sections and moored current meter arrays. We emphasize 165°E, between 30° and 42°N, where high quality and very ...

Terrence M. Joyce; William J. Schmitz

1988-11-01T23:59:59.000Z

291

Near-Surface Measurements of Quasi-Lagrangian Velocities in Open Water  

Science Conference Proceedings (OSTI)

Near-surface water velocities have been measured in the coastal zone of Lake Huron and Cape Cod Bay by tracking drifters and drogues using acoustic travel time and compass sighting techniques. The near-surface current, defined as the velocity of ...

J. H. Churchill; G. T. Csanady

1983-09-01T23:59:59.000Z

292

Effect of temperature on wave velocities in sands and sandstones with heavy hydrocarbons  

SciTech Connect

A laboratory investigation was made of the effects of temperature on wave velocities in sandstones and unconsolidated sand saturated with heavy hydrocarbons. The large decreases of the compressional and shear velocities in such sandstones and sand with increasing temperature suggest that seismic methods may be very useful in detecting heat fronts in heavy hydrocarbon reservoirs undergoing steamflooding or in-situ combustion.

Wang, Z.; Nur, A.

1988-02-01T23:59:59.000Z

293

A new method of measurement of the velocities of solar neutrinos  

E-Print Network (OSTI)

A new method of measurement of the velocities of solar electron antineutrinos is proposed. The method is based on the assumption, that if the neutrino detector having a shape of a pipe and providing a proper angular resolution, is directed onto the optical "image" of the sun, then it would detect solar neutrinos with velocities $V_{\\widetilde{\

Elmir Dermendjiev

2006-01-22T23:59:59.000Z

294

An Integrating Velocity–Azimuth Process Single-Doppler Radar Wind Retrieval Method  

Science Conference Proceedings (OSTI)

Among the single-Doppler radar wind analysis methods, the velocity–azimuth display (VAD), velocity–azimuth process (VAP), and uniform-wind (UW) methods are widely used because of their simplicity. This paper shows that the VAD, VAP, and UW ...

Xudong Liang

2007-04-01T23:59:59.000Z

295

Modeling the Dry Deposition Velocity of Sulfur Dioxide and Sulfate in Asia  

Science Conference Proceedings (OSTI)

The dry deposition model was created to estimate SO2 and sulfate dry deposition velocities over nine land use types in Asia. The study domain is 20°S–50°N, 39°–154°E. Monthly averaged 1° × 1° dry deposition velocities are estimated for four ...

Yiwen Xu; Gregory R. Carmichael

1998-10-01T23:59:59.000Z

296

Electromagnetic plane waves with negative phase velocity in charged black strings  

SciTech Connect

We investigate the propagation regions of electromagnetic plane waves with negative phase velocity in the ergosphere of static charged black strings. For such a propagation, some conditions for negative phase velocity are established that depend on the metric components and the choice of the octant. We conclude that these conditions remain unaffected by the negative values of the cosmological constant.

Sharif, M., E-mail: msharif.math@pu.edu.pk; Manzoor, R., E-mail: rubabmanzoor9@yahoo.com [University of the Punjab, Department of Mathematics (Pakistan)

2013-02-15T23:59:59.000Z

297

Observations of Near-Surface Oceanic Velocity Strain-Rate Variability during and after Storm Events  

Science Conference Proceedings (OSTI)

During August of 1977, a series of repeated profiles of the upper ocean were made at Ocean Station Papa (145°W, 50°N) with a velocity/temperature microstructure profiler. A strong correlation of wind-speed variations with velocity structures in ...

R. Eward Lange

1981-09-01T23:59:59.000Z

298

Finescale Velocity-Density Characteristics and Richardson Number Statistics of the Eastern Equatorial Pacific  

Science Conference Proceedings (OSTI)

An analysis of finescale horizontal-velocity shear and density data collected along 110°W longitude in the equatorial Pacific is presented. The measurements were made with the free-fall velocity–density profiler, TOPS. Twenty-five deployments are ...

John M. Toole; Stanley P. Hayes

1984-04-01T23:59:59.000Z

299

POST-SHOCK TEMPERATURE AND FREE SURFACE VELOCITY MEASUREMENTS OF BASALT  

E-Print Network (OSTI)

POST-SHOCK TEMPERATURE AND FREE SURFACE VELOCITY MEASUREMENTS OF BASALT S. T. Stewart1 , G. B is the most common rock type on planetary surfaces. Post-shock temperature and particle velocity measurements River basalt released from a peak shock pressure of 28.9±0.2 GPa, the apparent post-shock temperature

Stewart, Sarah T.

300

Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method  

SciTech Connect

Seismic refraction method is one of the most popular methods in assessing surface excavation. The main objective of the seismic data acquisition is to delineate the subsurface into velocity profiles as different velocity can be correlated to identify different materials. The physical principal used for the determination of excavatability is that seismic waves travel faster through denser material as compared to less consolidated material. In general, a lower velocity indicates material that is soft and a higher velocity indicates more difficult to be excavated. However, a few researchers have noted that seismic velocity method alone does not correlate well with the excavatability of the material. In this study, a seismic velocity method was used in Nusajaya, Johor to assess the accuracy of this seismic velocity method with excavatability of the weathered sedimentary rock mass. A direct ripping run by monitoring the actual production of ripping has been employed at later stage and compared to the ripper manufacturer's recommendation. This paper presents the findings of the seismic velocity tests in weathered sedimentary area. The reliability of using this method with the actual rippability trials is also presented.

Bin Mohamad, Edy Tonnizam; Noor, Muhazian Md; Isa, Mohamed Fauzi Bin Md.; Mazlan, Ain Naadia [Department of Geotechnics and Transportation, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai. Johor (Malaysia); Saad, Rosli [Universiti Sains Malaysia, Penang (Malaysia)

2010-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

SAE Paper 2004-01-2936 Molecular Structure Effects On Laminar Burning Velocities At  

E-Print Network (OSTI)

1 SAE Paper 2004-01-2936 Molecular Structure Effects On Laminar Burning Velocities At Elevated and Engineering Copyright © 2004 Society of Automotive Engineers, Inc ABSTRACT The laminar burning velocities and pressure of 304 kPa. Data have been acquired over the stoichiometry range of 0.55 1.4. The burning

Androulakis, Ioannis (Yannis)

302

Brief paper: Global trajectory tracking control of VTOL-UAVs without linear velocity measurements  

Science Conference Proceedings (OSTI)

This paper deals with the position control of Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs) without linear velocity measurements. We propose a multistage constructive procedure, exploiting the cascade property of the translational ... Keywords: Linear-velocity observer, Trajectory tracking, Unmanned Aerial Vehicles

Abdelkader Abdessameud; Abdelhamid Tayebi

2010-06-01T23:59:59.000Z

303

Reduced-dissipation remapping of velocity in staggered arbitrary Lagrangian-Eulerian methods  

Science Conference Proceedings (OSTI)

Remapping is an essential part of most Arbitrary Lagrangian-Eulerian (ALE) methods. In this paper, we focus on the part of the remapping algorithm that performs the interpolation of the fluid velocity field from the Lagrangian to the rezoned computational ... Keywords: Conservative interpolations, Flux-based remap, Staggered discretization, Velocity remap

David Bailey; Markus Berndt; Milan Kucharik; Mikhail Shashkov

2010-04-01T23:59:59.000Z

304

Results from a Velocity Transect Along the Equator from 125 to 159°W  

Science Conference Proceedings (OSTI)

During March–April 1980, a velocity and CTD transect was made in the Pacific along the equator from 110 to 180°W. The horizontal baroclinic pressure gradient was observed to be primary confined between 160 and 130°W. Direct velocity profiles ...

Ants Leetmaa; Peter F. Spain

1981-07-01T23:59:59.000Z

305

Preliminary assessment of the velocity pump reaction turbine as a geothermal total-flow expander  

DOE Green Energy (OSTI)

A preliminary evaluation was made of the Velocity Pump Reaction Turbine (VPRT) as a total flow expander in a geothermal-electric conversion cycle. Values of geofluid effectiveness of VPRT systems were estimated for conditions consisting of: a 360/sup 0/ geothermal resource, 60/sup 0/F wet-bulb ambient temperature, zero and 0.003 mass concentrations of dissolved noncondensible gas in the geofluid, 100 and 120/sup 0/F condensing temperatures, and engine efficiencies ranging from 0.4 to 1.0. Achievable engine efficiencies were estimated to range from 0.47 to 0.77, with plant geofluid effectiveness values ranging as high as 9.5 Watt hr/lbm geofluid for the 360/sup 0/F resource temperature. This value is competitive with magnitudes of geofluid effectiveness projected for advanced binary plants, and is on the order of 40% higher than estimates for dual-flash steam and other total flow systems reviewed. Because of its potentially high performance and relative simplicity, the VPRT system appears to warrant further investigation toward its use in a well-head geothermal plant.

Demuth, O.J.

1984-06-01T23:59:59.000Z

306

Formation and evolution of interstellar filaments; Hints from velocity dispersion measurements  

E-Print Network (OSTI)

We investigate the gas velocity dispersions of a sample of filaments recently detected as part of the Herschel Gould Belt Survey in the IC5146, Aquila, and Polaris interstellar clouds. To measure these velocity dispersions, we use 13CO, C18O, and N2H+ line observations obtained with the IRAM 30m telescope. Correlating our velocity dispersion measurements with the filament column densities derived from Herschel data, we show that interstellar filaments can be divided into two regimes: thermally subcritical filaments, which have transonic velocity dispersions (c_s ~dispersions scaling roughly as the square root of column density (\\sigma_tot ~ \\Sigma^0.5), and are self-gravitating. The higher velocity dispersions of supercritical filaments may not directly arise from supersonic interstellar turbulence but may be driven by gravitational contraction/accretion...

Arzoumanian, Doris; Peretto, Nicolas; Konyves, Vera

2013-01-01T23:59:59.000Z

307

Velocity Measurements at Three Fish Screening Facilities in the Yakima Basin, Washington : Summer 1989 Annual Report.  

DOE Green Energy (OSTI)

The Pacific Northwest Laboratory (PNL) measured the velocity conditions at three fish screening facilities in the Yakima River Basin: Wapato, Chandler, and Easton Screens. The measurement objectives were different at the three screens. At Wapato, approach and sweep velocities were measured to evaluate the effect of rearing pens in the screen forebay. A complete survey was performed at the Chandler Screens. At Easton, velocity was measured behind the screens to provide information for the installation of porosity boards to balance flow through the screens. Salmon-rearing pens used at the Wapato Canal had a minimal effect on the magnitude of approach and sweep velocities at the face of the drum screens, although the pens caused increased turbulence and variability in water velocities. The net pens did not appear to affect flows through the three fish bypasses. 8 refs., 17 figs., 5 tabs.

Abernethy, C. Scott; Neitzel, Duane A.; Lusty, E. William

1990-09-01T23:59:59.000Z

308

P wave velocity variations in the Coso region, California, derived from  

Open Energy Info (EERE)

P wave velocity variations in the Coso region, California, derived from P wave velocity variations in the Coso region, California, derived from local earthquake travel times Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: P wave velocity variations in the Coso region, California, derived from local earthquake travel times Details Activities (1) Areas (1) Regions (0) Abstract: Inversion of 4036 P wave travel time residuals from 429 local earthquakes using a tomographic scheme provides information about three-dimensional upper crustal velocity variations in the Indian Wells Valley-Coso region of southeastern California. The residuals are calculated relative to a Coso-specific velocity model, corrected for station elevation, weighted, and back-projected along their ray paths through models defined with layers of blocks. Slowness variations in the surface

309

Competitions between Rayleigh-Taylor instability and Kelvin-Helmholtz instability with continuous density and velocity profiles  

Science Conference Proceedings (OSTI)

In this research, competitions between Rayleigh-Taylor instability (RTI) and Kelvin-Helmholtz instability (KHI) in two-dimensional incompressible fluids within a linear growth regime are investigated analytically. Normalized linear growth rate formulas for both the RTI, suitable for arbitrary density ratio with continuous density profile, and the KHI, suitable for arbitrary density ratio with continuous density and velocity profiles, are obtained. The linear growth rates of pure RTI ({gamma}{sub RT}), pure KHI ({gamma}{sub KH}), and combined RTI and KHI ({gamma}{sub total}) are investigated, respectively. In the pure RTI, it is found that the effect of the finite thickness of the density transition layer (L{sub {rho}}) reduces the linear growth of the RTI (stabilizes the RTI). In the pure KHI, it is found that conversely, the effect of the finite thickness of the density transition layer increases the linear growth of the KHI (destabilizes the KHI). It is found that the effect of the finite thickness of the density transition layer decreases the ''effective'' or ''local'' Atwood number (A) for both the RTI and the KHI. However, based on the properties of {gamma}{sub RT}{proportional_to}{radical}(A) and {gamma}{sub KH}{proportional_to}{radical}(1-A{sup 2}), the effect of the finite thickness of the density transition layer therefore has a completely opposite role on the RTI and the KHI noted above. In addition, it is found that the effect of the finite thickness of the velocity shear layer (L{sub u}) stabilizes the KHI, and for the most cases, the combined effects of the finite thickness of the density transition layer and the velocity shear layer (L{sub {rho}=}L{sub u}) also stabilize the KHI. Regarding the combined RTI and KHI, it is found that there is a competition between the RTI and the KHI because of the completely opposite effect of the finite thickness of the density transition layer on these two kinds of instability. It is found that the competitions between the RTI and the KHI depend, respectively, on the Froude number, the density ratio of the light fluid to the heavy one, and the finite thicknesses of the density transition layer and the velocity shear layer. Furthermore, for the fixed Froude number, the linear growth rate ratio of the RTI to the KHI decreases with both the density ratio and the finite thickness of the density transition layer, but increases with the finite thickness of the velocity shear layer and the combined finite thicknesses of the density transition layer and the velocity shear layer (L{sub {rho}=}L{sub u}). In summary, our analytical results show that the effect of the finite thickness of the density transition layer stabilizes the RTI and the overall combined effects of the finite thickness of the density transition layer and the velocity shear layer (L{sub {rho}=}L{sub u}) also stabilize the KHI. Thus, it should be included in applications where the transition layer effect plays an important role, such as the formation of large-scale structures (jets) in high energy density physics and astrophysics and turbulent mixing.

Ye, W. H.; He, X. T. [Department of Physics, Zhejiang University, Hangzhou 310027 (China); CAPT, Peking University, Beijing 100871 (China); LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Wang, L. F. [CAPT, Peking University, Beijing 100871 (China); LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); SMCE, China University of Mining and Technology, Beijing 100083 (China); Xue, C.; Fan, Z. F. [LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2011-02-15T23:59:59.000Z

310

VELOCITY-FIELD MEASUREMENTS OF A SHOCK-ACCELERATED FLUID INSTABILITY  

Science Conference Proceedings (OSTI)

A cylinder of heavy gas (SF{sub 6}) in air is hit by a Mach 1.2 shock. The resultant Richtmyer-Meshkov instability is observed as it propagates through the test section of the shock tube. Six images are taken after shock impact, and the velocity field at one time is measured using Particle Image Velocimetry (PIV). The images of the density field show the development of a secondary instability in the cylinder. The velocity field provides us with information about the magnitudes of the velocities as well as the magnitude of the vorticity in the flow.

K. PRESTRIDGE; C. ZOLID; ET AL

2001-05-01T23:59:59.000Z

311

Tool and a method for obtaining hydrologic flow velocity measurements in geothermal reservoirs  

Science Conference Proceedings (OSTI)

Downhole instruments based on a thermal perturbation principle are being developed to measure heat flow in permeable formations where convective transport of heat is important. To make heat flow measurements in these regions, the ground water velocity vector must be determined. A downhole probe has been designed to measure the local ground water velocity vector. The probe is a cylindrical heat source operated at a constant heat flux. In a convecting environment, surface temperatures on the probe are perturbed from those values of a purely conductive environment. With the aid of analytical and numerical models, these temperature differences can be related to the local velocity vector. 4 refs., 2 figs.

Carrigan, C.R.; Dunn, J.C.; Hardee, H.C.

1986-01-01T23:59:59.000Z

312

Measurement of velocity deficit at the downstream of a 1:10 axial hydrokinetic turbine model  

DOE Green Energy (OSTI)

Wake recovery constrains the downstream spacing and density of turbines that can be deployed in turbine farms and limits the amount of energy that can be produced at a hydrokinetic energy site. This study investigates the wake recovery at the downstream of a 1:10 axial flow turbine model using a pulse-to-pulse coherent Acoustic Doppler Profiler (ADP). In addition, turbine inflow and outflow velocities were measured for calculating the thrust on the turbine. The result shows that the depth-averaged longitudinal velocity recovers to 97% of the inflow velocity at 35 turbine diameter (D) downstream of the turbine.

Gunawan, Budi [ORNL; Neary, Vincent S [ORNL; Hill, Craig [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414; Chamorro, Leonardo [St. Anthony Falls Laboratory, 2 Third Avenue SE, Minneapolis, MN 55414

2012-01-01T23:59:59.000Z

313

Structure of the mean velocity and turbulence in premixed axisymmetric acetylene flames  

Science Conference Proceedings (OSTI)

Laser-Doppler measurements of axial mean velocities and the corresponding rms values of turbulent velocity fluctuations are reported for premixed, axisymmetric, acetylene flames together with the probability density distributions of the turbulent velocity fluctuations. All this information provides an insight into the structure of the flow field. Characteristic zones of the flow field are defined that show common features for all acetylene flames studied by the authors. These features are discussed in the paper and are suggested to characterize, in general, interesting parts of the flames.

Matovic, M.; Oka, S. (Inst. for Thermal Engineering and Energy Research, Beograd (Yugoslavia)); Durst, F. (Univ. Erlangen-Nuernberg, Erlangen (Germany). Lehrstuhl fuer Stroemungsmechanik)

1994-09-01T23:59:59.000Z

314

Contribution from cosmological scalar perturbations to the angular velocity spectrum of extragalactic sources  

SciTech Connect

The possibility of the influence of adiabatic scalar perturbations on the angular velocity spectrum of extragalactic sources is considered. The multipole expansion coefficients of the angular velocity field in terms of vector spherical harmonics are calculated. We show that there is no contribution from adiabatic perturbations to the angular spectrum for a spatially flat Universe at the dusty stage, while there is a contribution only to the electric multiple coefficients at the stage of {Lambda}-term domination. The cases of long-wavelength and short-wavelength perturbations are considered separately. The relationship between the multipole angular velocity spectrum and the primordial scalar perturbation spectrum is discussed.

Marakulin, A. O., E-mail: marakulin@physics.msu.ru; Sazhina, O. S.; Sazhin, M. V. [Moscow State University (Russian Federation)

2012-07-15T23:59:59.000Z

315

Impact of assimilating ocean velocity observations inferred from Lagrangian drifter data using the NCOM-4DVAR  

Science Conference Proceedings (OSTI)

Eulerian velocity fields are derived from 300 drifters released in the Gulf of Mexico by The Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) during the summer 2012 Grand Lagrangian Deployment (GLAD) ...

Matthew J. Carrier; Hans Ngodock; Scott Smith; Gregg Jacobs; Philip Muscarella; Tamay Ozgokmen; Brian Haus; Bruce Lipphardt

316

USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE GEOLOGIC  

Open Energy Info (EERE)

USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE GEOLOGIC USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE GEOLOGIC AND HYDROLOGIC STRUCTURE WITHIN THE COSO GEOTHERMAL FIELD, CALIFORNIA Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE GEOLOGIC AND HYDROLOGIC STRUCTURE WITHIN THE COSO GEOTHERMAL FIELD, CALIFORNIA Details Activities (1) Areas (1) Regions (0) Abstract: We relocate 14 years of seismicity in the Coso Geothermal Field using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We utilize over 60,000 micro-seismic events using waveform crosscorrelation to augment the expansive catalog of Pand S-wave

317

ARM - PI Product - Cloud-Scale Vertical Velocity and Turbulent Dissipation  

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

ProductsCloud-Scale Vertical Velocity and Turbulent ProductsCloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals Site(s) NSA General Description Time-height fields of retrieved in-cloud vertical wind velocity and turbulent dissipation rate, both retrieved primarily from vertically-pointing, Ka-band cloud radar measurements. Files are available for manually-selected, stratiform, mixed-phase cloud cases observed at the North Slope of Alaska (NSA) site during periods covering the Mixed-Phase Arctic Cloud Experiment (MPACE, late September through early November 2004) and the Indirect and Semi-Direct Aerosol Campaign (ISDAC, April-early May

318

ARM - PI Product - SGP and TWP (Manus) Ice Cloud Vertical Velocities  

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

ProductsSGP and TWP (Manus) Ice Cloud Vertical ProductsSGP and TWP (Manus) Ice Cloud Vertical Velocities Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : SGP and TWP (Manus) Ice Cloud Vertical Velocities 1997.01.01 - 2010.12.31 Site(s) SGP TWP General Description Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Lower level clouds are removed, however a multi-layer flag is included.

319

The Finescale Response of Lowered ADCP Velocity Measurements Processed with Different Methods  

Science Conference Proceedings (OSTI)

In a paper published in 2002 in this journal, K. Polzin et al. derive corrections for spectra of vertical shear calculated from lowered acoustic Doppler current profiler (LADCP) velocity data. To illustrate and validate the corrections, they use ...

A. M. Thurnherr

2012-04-01T23:59:59.000Z

320

Velocity Structure of Internal Tide Beams Emanating from Kaena Ridge, Hawaii  

Science Conference Proceedings (OSTI)

Observations are reported of the semidiurnal (M2) internal tide across Kaena Ridge, Hawaii. Horizontal velocity in the upper 1000–1500 m was measured during eleven ~240-km-long shipboard acoustic Doppler current profiler (ADCP) transects across ...

Andy Pickering; Matthew H. Alford

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Complementarity of weak lensing and peculiar velocity measurements in testing general relativity  

SciTech Connect

We explore the complementarity of weak lensing and galaxy peculiar velocity measurements to better constrain modifications to General Relativity. We find no evidence for deviations from General Relativity on cosmological scales from a combination of peculiar velocity measurements (for Luminous Red Galaxies in the Sloan Digital Sky Survey) with weak lensing measurements (from the Canadian France Hawaii Telescope Legacy Survey). We provide a Fisher error forecast for a Euclid-like space-based survey including both lensing and peculiar velocity measurements and show that the expected constraints on modified gravity will be at least an order of magnitude better than with present data, i.e. we will obtain {approx_equal}5% errors on the modified gravity parametrization described here. We also present a model-independent method for constraining modified gravity parameters using tomographic peculiar velocity information, and apply this methodology to the present data set.

Song, Yong-Seon [Korea Institute for Advanced Study, Dongdaemun-gu, Seoul 130-722 (Korea, Republic of); Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom); Zhao Gongbo; Bacon, David; Koyama, Kazuya; Nichol, Robert C. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth, PO1 3FX (United Kingdom); Pogosian, Levon [Department of Physics, Simon Fraser University, Burnaby, BC, V5A 1S6 (Canada)

2011-10-15T23:59:59.000Z

322

Surface Eddy Momentum Flux and Velocity Variances in the Southern Ocean from Geosat Altimetry  

Science Conference Proceedings (OSTI)

Satellite altimetry has previously been used to map the magnitude of the surface eddy variability of the global oceans, but the direction of the time-variable velocities have been more difficult to determine. Here, a technique is presented for ...

Rosemary Morrow; Richard Coleman; John Church; Dudley Chelton

1994-10-01T23:59:59.000Z

323

A Study on the Temperature Variation of Rise Velocity for Large Clean Bubbles  

Science Conference Proceedings (OSTI)

A series of microphysical laboratory experiments studying the hydrodynamics of single bubbles were conducted to measure the variation of rise velocity, VB, with temperature, T, and radius, r. Bubbles with an equivalent spherical radius between ...

Ira Leifer; Ranjan K. Patro; Peter Bowyer

2000-10-01T23:59:59.000Z

324

Chirp-Induced Bias in Velocity Measurements by a Coherent Doppler CO2 Lidar  

Science Conference Proceedings (OSTI)

Radial wind velocity measurements by a pulsed CO2 Doppler lidar may be biased even in stationary atmospheric conditions. The authors show it is due to random speckle fluctuations of the backscattered signal and is related to the dissymmetry of ...

Alain M. Dabas; Philippe Drobinski; Pierre H. Flamant

1998-04-01T23:59:59.000Z

325

Horizontal Divergence and Vertical Velocity Retrievals from Doppler Radar and Wind Profiler Observations  

Science Conference Proceedings (OSTI)

Vertical motion profiles can be diagnosed with the mass continuity equation using horizontal divergence fields derived from various single-Doppler radar techniques such as EVAD (extended velocity-azimuth display), CEVAD (concurrent extended ...

Robert Cifelli; Steven A. Rutledge; Dennis J. Boccippio; Thomas Matejka

1996-10-01T23:59:59.000Z

326

The Coupling of Vertical Velocity and Signal Power Observed with the SOUSY VHF Radar  

Science Conference Proceedings (OSTI)

The perturbations to the static stability (and hence to the radar reflectivity) and to the velocity in a vertically propagating gravity wave are correlated, and the sign of the correlation depends on whether the wave is propagating upward or ...

G. D. Nastrom; R. Rüster; G. Schmidt

1998-01-01T23:59:59.000Z

327

Operational Multiple-Doppler Wind Retrieval Inferred from Long-Range Radial Velocity Measurements  

Science Conference Proceedings (OSTI)

The recent deployment of an innovative triple pulse rise time (PRT) scheme within the French operational radar network allows for the simultaneous collection of reflectivity and radial velocity measurements up to a range of 250 km with no ...

Olivier Bousquet; Pierre Tabary; Jacques Parent du Châtelet

2008-11-01T23:59:59.000Z

328

The upper crustal P-wave velocity structure of Newberry volcano, Central Oregon.  

E-Print Network (OSTI)

?? The upper-crustal seismic-velocity structure of Newberry volcano, central Oregon, is imaged using P-wave travel time tomography. The inversion combines a densely-spaced seismic line collected… (more)

Beachly, Matthew William

2011-01-01T23:59:59.000Z

329

The Upper Crustal P-wave Velocity Structure of Newberry Volcano, Central Oregon.  

E-Print Network (OSTI)

??The upper-crustal seismic-velocity structure of Newberry volcano, central Oregon, is imaged using P-wave travel time tomography. The inversion combines a densely-spaced seismic line collected in… (more)

Beachly, Matthew William, 1986-

2011-01-01T23:59:59.000Z

330

Dealiasing Doppler Velocities Measured by a Bistatic Radar Network during a Downburst-Producing Thunderstorm  

Science Conference Proceedings (OSTI)

The object of this paper was to develop an automated dealiasing scheme that dealiases Doppler velocities measured by a bistatic Doppler radar network. The particular network consists of the C-band polarimetric diversity Doppler radar, POLDIRAD, ...

Katja Friedrich; Olivier Caumont

2004-05-01T23:59:59.000Z

331

Inversion for subbottom sound velocity profiles in the deep and shallow ocean  

E-Print Network (OSTI)

This thesis investigates the application of acoustic measurements in the deep and shallow ocean to infer the sound velocity profile (svp) in the seabed. For the deep water ocean, an exact method based on the Gelfand-Levitan ...

Souza, Luiz Alberto Lopes de

2005-01-01T23:59:59.000Z

332

Estimates of the Seasonal Mean Vertical Velocity Fields of the Extratropical Northern Hemisphere  

Science Conference Proceedings (OSTI)

Wintertime and summertime mean 500 mb vertical velocity fields for the extratropical Northern Hemisphere are calculated by several methods from general circulation statistics compiled from National Meteorological Center (NMC) operational analyses ...

Glenn H. White

1983-07-01T23:59:59.000Z

333

Instrumental Uncertainties in Z–R Relationships and Raindrop Fall Velocities  

Science Conference Proceedings (OSTI)

This study demonstrates the sensitivity of reflectivity–rainfall rate (Z–R) relationships, which were derived from disdrometer-based drop size distribution measurements, to the fall velocity of the drops. The dataset used comes from the ...

Christian Salles; Jean-Dominique Creutin

2003-02-01T23:59:59.000Z

334

Vertical Velocity and Microphysical Distributions Related to Rapid Intensification in a Simulation of Hurricane Dennis (2005)  

Science Conference Proceedings (OSTI)

A 1-km Weather Research and Forecasting model simulation of Hurricane Dennis was used to identify precursors in vertical velocity and latent heating distributions to rapid intensification (RI). Although the observed structure qualitatively ...

Greg M. McFarquhar; Brian F. Jewett; Matthew S. Gilmore; Stephen W. Nesbitt; Tsung-Lin Hsieh

2012-12-01T23:59:59.000Z

335

The Effect of Nonlinear Drag on the Motion and Settling Velocity of Heavy Particles  

Science Conference Proceedings (OSTI)

The effects of nonlinear drag on the motion and settling velocity of heavy particles in a turbulent atmosphere are investigated. The authors approach the problem rather systematically by first considering the response of particles to much simpler ...

J. E. Stout; S. P. Arya; E. L. Genikhovich

1995-11-01T23:59:59.000Z

336

Estimating the Vertical Component of Water Velocity from Measurements Collected with a Free-fall Vehicle  

Science Conference Proceedings (OSTI)

Estimated of the vertical component of water velocity are made with measurements of the pressure-change rate and rotation rate recorded by the free-fall vehicle “Cartesian diver” (CD). Using buoyancy control, this device moves alternately up and ...

David C. Jacobs; Charles S. Cox

1992-02-01T23:59:59.000Z

337

Determining Turbulent Vertical Velocity, and Fluxes of Heat and Salt with an Autonomous Underwater Vehicle  

Science Conference Proceedings (OSTI)

The authors show that vertical turbulent fluxes in the upper ocean can be measured directly with an autonomous underwater vehicle (AUV). A horizontal profile of vertical water velocity is obtained by applying a Kalman smoother to AUV motion data. ...

Daniel R. Hayes; James H. Morison

2002-05-01T23:59:59.000Z

338

Characteristics of Vertical Velocity Cores in Different Convective Systems Observed over Gadanki, India  

Science Conference Proceedings (OSTI)

The Indian mesosphere–stratosphere–troposphere (MST) radar measurements during the passage of 60 convective systems are used to study the vertical air velocity (w) characteristics of tropical convection. The up- and downdraft cores and various ...

K. N. Uma; T. Narayana Rao

2009-03-01T23:59:59.000Z

339

Climatology of Velocity and Temperature Turbulence Statistics Determined from Rawinsonde and ACARS/AMDAR Data  

Science Conference Proceedings (OSTI)

The climatology of the spatial structure functions of velocity and temperature for various altitudes (pressure levels) and latitude bands is constructed from the global rawinsonde network and from Aircraft Communications, Addressing, and ...

Rod Frehlich; Robert Sharman

2010-06-01T23:59:59.000Z

340

Parameter estimation of permanent magnet stepper motors without position or velocity sensors  

E-Print Network (OSTI)

Parameter estimation of permanent magnet stepper motors without position or velocity sensors Romain identification method for permanent magnet stepper motors. Current sensors are assumed available, but position magnet stepper motors, syn- chronous motors, sensorless systems, parameter identification, elimination

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "high velocity sdhv" 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

Low-Frequency Velocity and Temperature Fluctuations in Katabatic Valley Flows  

Science Conference Proceedings (OSTI)

Observations of velocity and temperature fluctuations made during katabatic flow conditions in two deeply incised valleys are analyzed using variance, coherence, and phase spectra. Variance spectra obtained at valley floor sidewall locations show ...

G. L. Stone; D. E. Hoard

1989-06-01T23:59:59.000Z

342

Estimation of Velocity from Argos-tracked Surface Drifters during OCEAN STORMS  

Science Conference Proceedings (OSTI)

Modern surface drifters tracked by Argos are an attractive method for measuring the spatial structure of near-surface currents. This note discusses the accuracy to which velocity can be estimated from such data, assuming perfect drifters. The ...

Eric A. D'Asaro

1992-10-01T23:59:59.000Z

343

A Hypothetical Burning-Velocity Formula for Very Lean Hydrogen-Air Mixtures  

E-Print Network (OSTI)

R.W. Shefer, Int. J. Hydrogen Energy 28 (2003) 1131-1141. P.burning velocities of lean hydrogen-air flames at 1 atm andFORMULA FOR VERY LEAN HYDROGEN-AIR MIXTURES by Forman A.

Grcar, Joseph F

2008-01-01T23:59:59.000Z

344

A Correction Method for Turbulence Measurements with a 3D Acoustic Doppler Velocity Profiler  

Science Conference Proceedings (OSTI)

A method is proposed to reduce the noise contribution to mean turbulence parameters obtained by 3D acoustic Doppler velocity profiler measurements. It is based on a noise spectrum reconstruction from cross-spectra evaluations of two independent ...

D. Hurther; U. Lemmin

2001-03-01T23:59:59.000Z

345

Real-Time Retrieval of the Wind from Aliased Velocities Measured by Doppler Radars  

Science Conference Proceedings (OSTI)

Doppler radar measurements provide the radial wind within an unambiguous interval due to the limited value of the sampling frequency (pulse repetition frequency). Many algorithms have been developed to retrieve true wind velocities from measured ...

Pierre Tabary; Georges Scialom; Urs Germann

2001-06-01T23:59:59.000Z

346

On Wind and Ocean-Velocity Correlations in a Coastal-Upwelling System  

Science Conference Proceedings (OSTI)

This note studies the response of a simple linear baroclinic coastal-upwelling model to fluctuating longshore winds. Correlations between wind stress and velocities are computed explicitly. It is shown that these correlations depend primarily ...

Benoit Cushman-Roisin; James J. O'Brien; Robert L. Smith

1983-03-01T23:59:59.000Z

347

Stabilization of a wheels carrying communication satellite without angle and angular velocity sensors  

Science Conference Proceedings (OSTI)

An algorithm of maintaining three-axis orbital orientation using limited angular motions of the gyrostat satellite is proposed. The algorithm uses measured angular velocity of rotation of the flywheel rotors and measured angular mismatches formed on ...

V. N. Branets; V. N. Platonov; A. V. Sumarokov; S. N. Timakov

2008-02-01T23:59:59.000Z

348

Hydraulic Interpretation of Direct Velocity Measurements in the Bab al Mandab  

Science Conference Proceedings (OSTI)

Acoustic Doppler Current Profiler velocity measurements in the Bab al Mandab during the period June 1995–March 1996 are used to assess the hydraulic character of the exchange flow. The strait is 150 km long and contains two distinct geometrical ...

L. J. Pratt; William Johns; Stephen P. Murray; Katsurou Katsumata

1999-11-01T23:59:59.000Z

349

On the Correction of Temperature and Velocity Time Series for Mooring Motion  

Science Conference Proceedings (OSTI)

Several schemes for correcting temperature and velocity measurements from moored current meters are tested on two moorings, one of which experienced large vertical excursions as the Gulf Stream meandered over it. The addition of two extra ...

Nelson G. Hogg

1986-03-01T23:59:59.000Z

350

An Electromagnetic Vorticity and Velocity Sensor for Observing Finescale Kinetic Fluctuations in the Ocean  

Science Conference Proceedings (OSTI)

An instrument has been developed that measures finescale velocity and vorticity in seawater based on the principles of motional induction. This instrument, the electromagnetic vorticity meter (EMVM), measures components of the gradient and ...

Thomas B. Sanford; James A. Carlson; John H. Dunlap; Mark D. Prater; Ren-Chieh Lien

1999-11-01T23:59:59.000Z

351

Sources of Gravity Wave Activity Seen in the Vertical Velocities Observed by the Flatland VHF Radar  

Science Conference Proceedings (OSTI)

Observations of vertical velocity made with the Flatland VHF radar located in the extremely flat terrain near Champaign, Illinois, are used to study sources of enhanced variance. The variance is used as an indicator of gravity wave activity. In ...

G. D. Nastrom; M. R. Peterson; J. L. Green; K. S. Gage; T. E. VanZandt

1990-08-01T23:59:59.000Z

352

Identifying Doppler Velocity Contamination Caused by Migrating Birds. Part II: Bayes Identification and Probability Tests  

Science Conference Proceedings (OSTI)

Based on the Bayesian statistical decision theory, a probabilistic quality control (QC) technique is developed to identify and flag migrating-bird-contaminated sweeps of level II velocity scans at the lowest elevation angle using the QC ...

Shun Liu; Qin Xu; Pengfei Zhang

2005-08-01T23:59:59.000Z

353

Prognostic Equation for Radar Radial Velocity Derived by Considering Atmospheric Refraction and Earth Curvature  

Science Conference Proceedings (OSTI)

The prognostic equation for the radial velocity field observed with a Doppler radar is derived to include the effects of atmospheric refraction and earth curvature on radar-beam height and slope angle. The derived equation, called the radial ...

Qin Xu; Li Wei

2013-10-01T23:59:59.000Z

354

Effects of Radar Sampling on Single-Doppler Velocity Signatures of Mesocyclones and Tornadoes  

Science Conference Proceedings (OSTI)

Simulated WSR-88D (Weather Surveillance Radar-1988 Doppler) radar data were used to investigate the effects of discrete azimuthal sampling on Doppler velocity signatures of modeled mesocyclones and tornadoes at various ranges from the radar and ...

Vincent T. Wood; Rodger A. Brown

1997-12-01T23:59:59.000Z

355

Simultaneous Velocity Ambiguity Resolution and Noise Suppression for Multifrequency Coherent Doppler Sonar  

Science Conference Proceedings (OSTI)

Coherent Doppler sonar is a useful tool for noninvasive measurement of ocean currents, sediment transport, and turbulence in coastal environments. Various methods have been proposed to separately address two of its inherent limitations: velocity ...

Jeremy Dillon; Len Zedel; Alex E. Hay

2012-03-01T23:59:59.000Z

356

Momentum Flux from Wind to Aqueous Flows at Various Wind Velocities and Fetches  

Science Conference Proceedings (OSTI)

The fraction of wind stress consumed in driving aqueous flows has been estimated for various nondimensional fetches, derived from the wind velocity, fetch, and gravitational acceleration. The fraction is shown to vary with both fetch and wind ...

Jin Wu

1988-01-01T23:59:59.000Z

357

Use of Mass- and Area-Dimensional Power Laws for Determining Precipitation Particle Terminal Velocities  

Science Conference Proceedings (OSTI)

Based on boundary layer theory and a comparison of empirical power laws relating the Reynolds and Best numbers, it was apparent that the primary variables governing a hydrometeor's terminal velocity were its mass, its area projected to the flow, ...

David L. Mitchell

1996-06-01T23:59:59.000Z

358

Rainfall Doppler Velocity Measurements from Spaceborne Radar: Overcoming Nonuniform Beam-Filling Effects  

Science Conference Proceedings (OSTI)

For vertical Doppler velocity measurements of a homogeneous rain field, the standard spectral moment estimation techniques commonly used by ground-based and airborne Doppler rain radars can be readily extended for spaceborne application, provided ...

Simone Tanelli; Eastwood Im; Stephen L. Durden; Luca Facheris; Dino Giuli; Eric A. Smith

2004-01-01T23:59:59.000Z

359

Extended Velocity Track Display (EVTD): An Improved Processing Method for Doppler Radar Observations of Tropical Cyclones  

Science Conference Proceedings (OSTI)

The authors present an improved version of the velocity track display (VTD) method, proposed by Lee et al., to deduce the primary vortex circulation in hurricanes from airborne Doppler radar data obtained during straightline legs through the ...

Frank Roux; Frank D. Marks Jr.

1996-08-01T23:59:59.000Z

360

Effect of an Insoluble Surface Film on the Drift Velocity of Capillary–Gravity Waves  

Science Conference Proceedings (OSTI)

The drift velocity due to capillary-gravity waves in a deep ocean is investigated theoretically. The surface is covered by an insoluble, inextensible film, and the analysis is based an a Lagrangian description of motion. Attenuated as well as ...

Jan Erik Weber; Even Førland

1989-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

The Temporal-Residual-Mean Velocity. Part I: Derivation and the Scalar Conservation Equations  

Science Conference Proceedings (OSTI)

The time-averaged density conservation equation in z coordinates contains a forcing term that is the divergence of the transient eddy fluxes. These fluxes are due to the temporal correlation between the instantaneous velocity and density fields. ...

Trevor J. McDougall; Peter C. McIntosh

1996-12-01T23:59:59.000Z

362

First Stellar Velocity Dispersion Measurement of a Luminous Quasar Host with Gemini North Laser Guide Star Adaptive Optics  

E-Print Network (OSTI)

We present the first use of the Gemini North laser guide star adaptive optics (LGS AO) system and an integral field unit (IFU) to measure the stellar velocity dispersion of the host of a luminous quasar. The quasar PG1426+015 (z=0.086) was observed with the Near-Infrared Integral Field Spectrometer (NIFS) on the 8m Gemini North telescope in the H-band as part of the Science Verification phase of the new ALTAIR LGS AO system. The NIFS IFU and LGS AO are well suited for host studies of luminous quasars because one can achieve a large ratio of host to quasar light. We have measured the stellar velocity dispersion of PG1426+015 from 0.1'' to 1'' (0.16 kpc to 1.6 kpc) to be 217+/-15 km/s based on high signal-to-noise ratio measurements of Si I, Mg I, and several CO bandheads. This new measurement is a factor of four more precise than a previous measurement obtained with long-slit spectroscopy and good, natural seeing, yet was obtained with a shorter net integration time. We find that PG1426+015 has a velocity dispersion that places it significantly above the M-sigma relation of quiescent galaxies and lower-luminosity active galactic nuclei with black hole masses estimated from reverberation mapping. We discuss several possible explanations for this discrepancy that could be addressed with similar observations of a larger sample of luminous quasars.

Linda C. Watson; Paul Martini; Kalliopi M. Dasyra; Misty C. Bentz; Laura Ferrarese; Bradley M. Peterson; Richard W. Pogge; Linda J. Tacconi

2008-06-19T23:59:59.000Z

363

Coupling between interface and velocity perturbations in the weakly nonlinear Rayleigh-Taylor instability  

Science Conference Proceedings (OSTI)

Weakly nonlinear (WN) Rayleigh-Taylor instability (RTI) initiated by single-mode cosinusoidal interface and velocity perturbations is investigated analytically up to the third order. Expressions of the temporal evolutions of the amplitudes of the first three harmonics are derived. It is shown that there are coupling between interface and velocity perturbations, which plays a prominent role in the WN growth. When the 'equivalent amplitude' of the initial velocity perturbation, which is normalized by its linear growth rate, is compared to the amplitude of the initial interface perturbation, the coupling between them dominates the WN growth of the RTI. Furthermore, the RTI would be mitigated by initiating a velocity perturbation with a relative phase shift against the interface perturbation. More specifically, when the phase shift between the interface perturbation and the velocity perturbation is {pi} and their equivalent amplitudes are equal, the RTI could be completely quenched. If the equivalent amplitude of the initial velocity perturbation is equal to the initial interface perturbation, the difference between the WN growth of the RTI initiated by only an interface perturbation and by only a velocity perturbation is found to be asymptotically negligible. The dependence of the WN growth on the Atwood numbers and the initial perturbation amplitudes is discussed. In particular, we investigate the dependence of the saturation amplitude (time) of the fundamental mode on the Atwood numbers and the initial perturbation amplitudes. It is found that the Atwood numbers and the initial perturbation amplitudes play a crucial role in the WN growth of the RTI. Thus, it should be included in applications where the seeds of the RTI have velocity perturbations, such as inertial confinement fusion implosions and supernova explosions.

Wang, L. F.; Ye, W. H.; He, X. T. [HEDPS and CAPT, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Wu, J. F.; Fan, Z. F.; Zhang, W. Y.; Dai, Z. S.; Gu, J. F.; Xue, C. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2012-11-15T23:59:59.000Z

364

Electromagnetic wave propagation with negative phase velocity in regular black holes  

SciTech Connect

We discuss the propagation of electromagnetic plane waves with negative phase velocity in regular black holes. For this purpose, we consider the Bardeen model as a nonlinear magnetic monopole and the Bardeen model coupled to nonlinear electrodynamics with a cosmological constant. It turns out that the region outside the event horizon of each regular black hole does not support negative phase velocity propagation, while its possibility in the region inside the event horizon is discussed.

Sharif, M., E-mail: msharif.math@pu.edu.pk; Manzoor, R., E-mail: rubabmanzoor9@yahoo.com [University of the Punjab, Department of Mathematics (Pakistan)

2012-12-15T23:59:59.000Z

365

Single-Doppler Velocity Retrievals with Phoenix II Data: Clear Air and Microburst Wind Retrievals in the Planetary Boundary Layer  

Science Conference Proceedings (OSTI)

A new three-dimensional single-Doppler velocity retrieval is introduced and tested with reflectivity and radial velocity data gathered during the Phoenix II field program near Boulder, Colorado. This retrieval is based on reflectivity ...

Alan Shapiro; Scott Ellis; Justin Shaw

1995-05-01T23:59:59.000Z

366

Improving Acoustic Doppler Current Profiler Accuracy with Wide-Area Differential GPS and Adaptive Smoothing of Ship Velocity  

Science Conference Proceedings (OSTI)

Accurate ship velocity is important for determining absolute currents from acoustic Doppler current profiler (ADCP) measurements. In this paper, the authors describe the application of two methods to improve the quality of ship velocity ...

Stephen D. Pierce; John A. Barth; Robert L. Smith

1999-05-01T23:59:59.000Z

367

The Size Distribution and Mass-Weighted Terminal Velocity of Low-Latitude Tropopause Cirrus Crystal Populations  

Science Conference Proceedings (OSTI)

Ice crystal terminal velocities govern the lifetime of radiatively complex, climatologically important, low-latitude tropopause cirrus clouds. To better understand cloud lifetimes, the terminal velocities of low-latitude tropopause cirrus cloud ...

C. G. Schmitt; A. J. Heymsfield

2009-07-01T23:59:59.000Z

368

PERIODIC MOTION IN HIGH-SYMMETRIC FLOW Lennaert van Veen  

E-Print Network (OSTI)

is supplied by fixing the smallest wave number components of velocity. The smallest wave number corresponding to a nonzero velocity component is kf = |kf | = 11 and the energy of these fixed components is Ef = 3PERIODIC MOTION IN HIGH-SYMMETRIC FLOW Lennaert van Veen Department of Mechanical Engineering

van Veen, Lennaert

369

Measurement of adiabatic burning velocity in natural gas-like mixtures  

SciTech Connect

Experimental measurements of the adiabatic burning velocities were carried out for natural gas-like mixtures burning in air over a range of equivalence ratios at atmospheric pressure. Effect of CO{sub 2} dilution up to 60%, N{sub 2} dilution up to 40% and 25% enrichment of ethane on burning velocity of methane-air flames were studied. Heat flux method with setup similar to that of [K.J. Bosschaart, L.P.H. de Goey, Detailed analysis of the heat flux method for measuring burning velocity, Combustion and Flame 132 (2003) 170-180] was used for measurement of burning velocities. Initially experiments were done for methane-air and ethane-air mixtures at various equivalence ratios and the results were in good agreement with published data in the literature. Computations were performed using PREMIX code with GRI 3.0 reaction mechanism for all the mixtures. Predicted flame structures were used to the explain the effect of N{sub 2} and CO{sub 2} dilution on burning velocity of methane-air flames. Peak burning velocity for CH{sub 4}/CO{sub 2}-air mixtures occur near to {phi} = 1.0. (author)

Ratna Kishore, V.; Duhan, Nipun; Ravi, M.R.; Ray, Anjan [Department of Mechanical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

2008-10-15T23:59:59.000Z

370

Spin-Orbit Alignment of the TrES-4 Transiting Planetary System and Possible Additional Radial-Velocity Variation  

E-Print Network (OSTI)

We report new radial velocities of the TrES-4 transiting planetary system, including observations of

Narita, Norio

371

Near-Surface Velocity Variability at Inertial and Subinertial Frequencies in the Vicinity of the California Current  

Science Conference Proceedings (OSTI)

Observations of the horizontal velocity field in the upper 150 m, made from the Research Platform FLIP as it drifted of the coast of Baja California, were used to examine the velocity of the velocity field and its relation to local wind forcing. ...

Robert A. Weller

1985-04-01T23:59:59.000Z

372

Correlations of whitecap coverage and gas transfer velocity with microwave brightness temperature for plunging and spilling breaking waves  

DOE Green Energy (OSTI)

Bubbles and bubble plumes generated by wind-induced breaking waves significantly enhance the gas exchange across the interface between the ocean and atmosphere under high-wind conditions. Whitcaps, or active spilling wave crests, are the sea-surface manifestation of the bubbles and bubble plumes in the subsurface mixed layer, and the fractional area of the sea surface covered by which has been proposed to correlate linearly with the air-sea gas transfer velocity. The presence of whitecaps substantially increases the microwave brightness temperature of the sea surface. It could be possible to estimate the whitecap coverage from the sea-surface microwave brightness temperature would also be very helpful in developing a remote-sensing model for predicting air-sea gas transfer velocities from microwave brightness temperatures. As a part of an air-water gas exchange experiment conducted in an outdoor surf pool, measurements were made that were designed to investigate the correlation between whitecap coverage and microwave brightness temperature. A mechanical wave maker was located at the deep end of the pool and the generated waves propagate and break towards the shallow end of the pool. Two wave patterns characteristic of plunging and spilling breaking waves at four wave heights from 0.3 m to 1.2 m were produced.

Wang, Qin; Monahan, E.C. [Connecticut Univ., Groton, CT (United States). Marine Sciences Inst.; Asher, W.E. [Battelle/Marine Sciences Lab., Sequim, WA (United States); Smith, P.M. [Naval Research Lab. Detachment, Stennis Space Center, MS (United States)

1995-07-01T23:59:59.000Z

373

An empirical model for the mean-velocity profiles of a turbulent boundary layer under the effects of surface curvature  

E-Print Network (OSTI)

An empirical model has been developed to predict the mean-velocity profile of a turbulent boundary layer under the influence of surface curvature. The model proposed is able to determine the profiles for both a convex and concave curvature. This was possible by employing the inviscid term, C,, which not only distinguishes the convex profiles from the concave profiles but its usage allows for a better prediction of these profiles. The model has been applied to experimental data from Schobeiri and Pardivala (1991) available from Texas A&M test facility. Along with these sets of data, experimental data from published literature such as So and Mellor (1973) and Kestoras and Simon (1993) have been employed in verifying the model. For all the cases, the model demonstrated a relatively high degree of accuracy in predicting the measured mean-velocity of the boundary layer and the estimated skin-friction coefficients. A skinfriction coefficient correlation has also been determined. C, is shown to affect the skinfriction coefficients in these cases.

Huynh, Long Quang

1994-01-01T23:59:59.000Z

374

Electron mobility and drift velocity in selectively doped InAlAs/InGaAs/InAlAs heterostructures  

Science Conference Proceedings (OSTI)

An increase in the electron mobility and drift velocity in high electric fields in quantum wells of selectively doped InAlAs/InGaAs/InAsAs heterostructures is obtained experimentally via controlling the composition of semiconductors forming the interface. The electron mobility at the interface in the In{sub 0.8}Ga{sub 0.2}As/In{sub 0.7}Al{sub 0.3}As metamorphic structure with a high molar fraction of In (0.7-0.8) is as high as 12.3 Multiplication-Sign 10{sup 3} cm{sup 2} V{sup -1} s{sup -1} at room temperature. An increase in the electron mobility by a factor of 1.1-1.4 is attained upon the introduction of thin (1-3 nm) InAs layers into a quantum well of selectively doped In{sub 0.53}Ga{sub 0.47}As/In{sub 0.52}Al{sub 0.48}As heterostructures. A maximal drift velocity attains 2.5 Multiplication-Sign 10{sup 7} cm/s in electric fields of 2-5 kV/cm. The threshold field F{sub th} for the intervalley {Gamma}-L electron transfer (the Gunn effect) in the InGaAs quantum well is higher than in the bulk material by a factor of 2.5-3. The effect of two- to threefold decrease in the threshold field F{sub th} in the InGaAs quantum well is established upon increasing the molar fraction of In in the InAlAs barrier, as well as upon the introduction of thin InAs inserts into the InGaAs quantum well.

Vasil'evskii, I. S., E-mail: pozela@pfi.lt; Galiev, G. B.; Klimov, E. A. [MEPHI National Nuclear Research University (Russian Federation); Pozela, K.; Pozela, J.; Juciene, V.; Suziedelis, A.; Zurauskiene, N.; Kersulis, S.; Stankevic, V. [Center for Physical Sciences and Technology, Semiconductor Physics Institute (Lithuania)

2011-09-15T23:59:59.000Z

375

VELOCITY CHARACTERISTICS OF EVAPORATED PLASMA USING HINODE/EUV IMAGING SPECTROMETER  

Science Conference Proceedings (OSTI)

This paper presents a detailed study of chromospheric evaporation using the EUV Imaging Spectrometer (EIS) onboard Hinode in conjunction with hard X-ray (HXR) observations from Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). The advanced capabilities of EIS were used to measure Doppler shifts in 15 emission lines covering the temperature range T = 0.05-16 MK during the impulsive phase of a C-class flare on 2007 December 14. Blueshifts indicative of the evaporated material were observed in six emission lines from Fe XIV-XXIV (2-16 MK). Upflow velocity (v{sub up}) was found to scale with temperature as v{sub up} (km s{sup -1}) {approx} 8-18T(MK). Although the hottest emission lines, Fe XXIII and Fe XXIV, exhibited upflows of >200 km s{sup -1}, their line profiles were found to be dominated by a stationary component in contrast to the predictions of the standard flare model. Emission from O VI-Fe XIII lines (0.5-1.5 MK) was found to be redshifted by v{sub down} (km s{sup -1}) {approx} 60-17T (MK) and was interpreted as the downward-moving 'plug' characteristic of explosive evaporation. These downflows occur at temperatures significantly higher than previously expected. Both upflows and downflows were spatially and temporally correlated with HXR emission observed by RHESSI that provided the properties of the electron beam deemed to be the driver of the evaporation. The energy flux of the electron beam was found to be {approx}>5 x 10{sup 10} erg cm{sup -2} s{sup -1}, consistent with the value required to drive explosive chromospheric evaporation from hydrodynamic simulations.

Milligan, Ryan O.; Dennis, Brian R. [Solar Physics Laboratory (Code 671), Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2009-07-10T23:59:59.000Z

376

METAL-POOR LITHIUM-RICH GIANTS IN THE RADIAL VELOCITY EXPERIMENT SURVEY  

Science Conference Proceedings (OSTI)

We report the discovery of eight lithium-rich field giants found in a high-resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H] < -0.5) selected from the Radial Velocity Experiment survey. The majority of the Li-rich giants in our sample are very metal-poor ([Fe/H] {approx}< -1.9), and have a Li abundance (in the form of {sup 7}Li), A(Li) = log (n(Li)/n(H)) + 12, between 2.30 and 3.63, well above the typical upper red giant branch (RGB) limit, A(Li) < 0.5, while two stars, with A(Li) {approx} 1.7-1.8, show similar lithium abundances to normal giants at the same gravity. We further included two metal-poor, Li-rich globular cluster giants in our sample, namely the previously discovered M3-IV101 and newly discovered (in this work) M68-A96. This comprises the largest sample of metal-poor Li-rich giants to date. We performed a detailed abundance analysis of all stars, finding that the majority of our sample stars have elemental abundances similar to that of Li-normal halo giants. Although the evolutionary phase of each Li-rich giant cannot be definitively determined, the Li-rich phase is likely connected to extra mixing at the RGB bump or early asymptotic giant branch that triggers cool bottom processing in which the bottom of the outer convective envelope is connected to the H-burning shell in the star. The surface of a star becomes Li-enhanced as {sup 7}Be (which burns to {sup 7}Li) is transported to the stellar surface via the Cameron-Fowler mechanism. We discuss and discriminate among several models for the extra mixing that can cause Li production, given the detailed abundances of the Li-rich giants in our sample.

Ruchti, Gregory R.; Fulbright, Jon P.; Wyse, Rosemary F. G. [Bloomberg Center for Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Gilmore, Gerard F. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Grebel, Eva K. [Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Moenchhofstr. 12-14, D-69120 Heidelberg (Germany); Bienayme, Olivier; Siebert, Arnaud [Observatoire de Strasbourg, 11 Rue de l'Universite, F-67000 Strasbourg (France); Bland-Hawthorn, Joss [Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia); Freeman, Ken C. [RSAA Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, Canberra, ACT 2611 (Australia); Gibson, Brad K. [Jeremiah Horrocks Institute for Astrophysics and Super-computing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Munari, Ulisse [INAF Osservatorio Astronomico di Padova, Via dell'Osservatorio 8, I-36012 Asiago (Italy); Navarro, Julio F. [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Station CSC, Victoria, BC V8W 3P6 (Canada); Parker, Quentin A.; Watson, Fred G. [Australian Astronomical Observatory, Coonabarabran, NSW 2357 (Australia); Reid, Warren [Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia); Seabroke, George M. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom); Siviero, Alessandro [Department of Astronomy, Padova University, Vicolo dell'Osservatorio 2, I-35122 Padova (Italy); Steinmetz, Matthias; Williams, Mary [Leibniz-Institut fuer Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Zwitter, Tomaz, E-mail: gruchti@mpa-garching.mpg.de [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SK-1000 Ljubljana (Slovenia)

2011-12-20T23:59:59.000Z

377

RECOMMENDED TRITIUM OXIDE DEPOSITION VELOCITY FOR USE IN SAVANNAH RIVER SITE SAFETY ANALYSES  

Science Conference Proceedings (OSTI)

The Defense Nuclear Facilities Safety Board (DNFSB) has recently questioned the appropriate value for tritium deposition velocity used in the MELCOR Accident Consequence Code System Ver. 2 (Chanin and Young 1998) code when estimating bounding dose (95th percentile) for safety analysis (DNFSB 2011). The purpose of this paper is to provide appropriate, defensible values of the tritium deposition velocity for use in Savannah River Site (SRS) safety analyses. To accomplish this, consideration must be given to the re-emission of tritium after deposition. Approximately 85% of the surface area of the SRS is forested. The majority of the forests are pine plantations, 68%. The remaining forest area is 6% mixed pine and hardwood and 26% swamp hardwood. Most of the path from potential release points to the site boundary is through forested land. A search of published studies indicate daylight, tritiated water (HTO) vapor deposition velocities in forest vegetation can range from 0.07 to 2.8 cm/s. Analysis of the results of studies done on an SRS pine plantation and climatological data from the SRS meteorological network indicate that the average deposition velocity during daylight periods is around 0.42 cm/s. The minimum deposition velocity was determined to be about 0.1 cm/s, which is the recommended bounding value. Deposition velocity and residence time (half-life) of HTO in vegetation are related by the leaf area and leaf water volume in the forest. For the characteristics of the pine plantation at SRS the residence time corresponding to the average, daylight deposition velocity is 0.4 hours. The residence time corresponding to the night-time deposition velocity of 0.1 cm/s is around 2 hours. A simple dispersion model which accounts for deposition and re-emission of HTO vapor was used to evaluate the impact on exposure to the maximally exposed offsite individual (MOI) at the SRS boundary (Viner 2012). Under conditions that produce the bounding, 95th percentile MOI exposure, i.e., low wind speed, weak turbulence, night, low deposition velocity, the effect of deposition and re-emission on MOI exposure was found to be very small. The exposure over the two hour period following arrival of the plume was found to be decreased by less than 0.05 %. Furthermore the sensitivity to deposition velocity was low. Increasing deposition velocity to 0.5 cm/s reduced exposure to 0.3 %. After a 24 hour period, an MOI would have been exposed to all of the released material. Based on the low sensitivity of MOI exposure to the value of deposition velocity when re-emission is considered, it is appropriately conservative to use a 0.0 cm/s effective deposition velocity for safety analysis in the MACCS2 code.

Lee, P.; Murphy, C.; Viner, B.; Hunter, C.; Jannik, T.

2012-04-03T23:59:59.000Z

378

In-Situ Continuous Detonation Velocity Measurements Using Fiber-optic Bragg Grating Sensors  

Science Conference Proceedings (OSTI)

In order to fully calibrate hydrocodes and dynamic chemistry burn models, initiation and detonation research requires continuous measurement of low order detonation velocities as the detonation runs up to full order detonation for a given density and initiation pressure pulse. A novel detector of detonation velocity is presented using a 125 micron diameter optical fiber with an integral chirped fiber Bragg grating as an intrinsic sensor. This fiber is embedded in the explosive under study and interrogated during detonation as the fiber Bragg grating scatters light back along the fiber to a photodiode, producing a return signal dependant on the convolution integral of the grating reflection bandpass, the ASE intensity profile and the photodetector response curve. Detonation velocity is measured as the decrease in reflected light exiting the fiber as the grating is consumed when the detonation reaction zone proceeds along the fiber sensor axis. This small fiber probe causes minimal perturbation to the detonation wave and can measure detonation velocities along path lengths tens of millimeters long. Experimental details of the associated equipment and preliminary data in the form of continuous detonation velocity records within nitromethane and PBX-9502 are presented.

Benterou, J; Udd, E; Wilkins, P; Roeske, F; Roos, E; Jackson, D

2007-07-25T23:59:59.000Z

379

On the Velocity in the Effective Field Theory of Large Scale Structures  

E-Print Network (OSTI)

We compute the renormalized two-point functions of density, divergence and vorticity of the velocity in the Effective Field Theory of Large Scale Structures. We show that the mass-weighted velocity, as opposed to the volume-weighted velocity, is the natural variable to use. We then prove that, Because of momentum and mass conservation, the corrections from short scales to the large-scale power spectra of density, divergence and vorticity must start at order $k^{4}$. For the vorticity this constitutes the leading term. Exact (approximated) self-similarity of an Einstein-de Sitter ($\\Lambda$CDM) background fixes the time dependence so that the vorticity power spectrum at leading order is uniquely determined, up to a normalization, by the symmetries of the problem. Focusing on density and velocity divergence, we show that the current formulation of the theory does not have enough counterterms to cancel all divergences. At the lowest order, the missing terms are a new stochastic noise and a heat conduction term in the continuity equation. For an Einstein de Sitter universe, we show that all three renormalized cross- and auto-correlation functions have the same structure but different numerical coefficients, which we compute. Using momentum instead of velocity, one can re-absorb the new terms and work with an uncorrected continuity equation but at the cost of having uncancelled IR divergences in equal-time correlators and a more complicated perturbation theory.

Lorenzo Mercolli; Enrico Pajer

2013-07-11T23:59:59.000Z

380

Stellar velocity dispersions and emission line properties of SDSS-III/BOSS galaxies  

E-Print Network (OSTI)

We perform a spectroscopic analysis of 492,450 galaxy spectra from the first two years of observations of the Sloan Digital Sky Survey-III/Baryonic Oscillation Spectroscopic Survey (BOSS) collaboration. This data set is released in the ninth SDSS data release in July 2012, the first public data release of BOSS spectra. We show that the typical signal-to-noise ratio of BOSS spectra, despite being low, is sufficient to measure stellar velocity dispersion and emission line fluxes for individual objects. We show that the typical velocity dispersion of a BOSS galaxy is ~240 km/s. The typical error in the velocity dispersion measurement 14 per cent, and 93 per cent of BOSS galaxies have velocity dispersions with an accuracy of better than 30 per cent. The distribution in velocity dispersion is redshift independent between redshifts 0.15 and 0.7, which reflects the survey design targeting massive galaxies with an approximately uniform mass distribution in this redshift interval. The majority of BOSS galaxies lack de...

Thomas, D; Maraston, C; Johansson, J; Beifiori, A; Pforr, J; Strombaeck, G; Tremonti, C A; Wake, D; Bizyaev, D; Bolton, A; Brewington, H; Browstein, J R; Comparat, J; Kneib, J P; Malanushenko, E; Malanushenko, V; Oravetz, D; Pan, K; Parejko, J K; Schneider, D P; Shelden, A; Simmons, A; Snedden, S; Tanaka, M; Weaver, B A; Yan, R

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" from the National Library of EnergyBeta (NLEBeta).
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381

A Comparison of VHF Radar Vertical-Velocity Measurements by a Direct Vertical-Beam Method and by a VAD Technique  

Science Conference Proceedings (OSTI)

Vertical-velocity measurements made by a direct vertical-beam method are compared to vertical velocities derived from VAD (velocity-azimuth display) measurements over a 27-h period. The results indicate that the two types of measurements in ...

M. F. Larsen; S. Fukao; O. Aruga; M. D. Yamanaka; T. Tsuda; S. Kato

1991-12-01T23:59:59.000Z

382

THE MILKY WAY'S CIRCULAR-VELOCITY CURVE BETWEEN 4 AND 14 kpc FROM APOGEE DATA  

Science Conference Proceedings (OSTI)

We measure the Milky Way's rotation curve over the Galactocentric range 4 kpc {approx}data from the Apache Point Observatory Galactic Evolution Experiment. We model the line-of-sight velocities of 3365 stars in 14 fields with b = 0 Degree-Sign between 30 Degree-Sign {99 % confidence. We find an offset between the Sun's rotational velocity and the local circular velocity of 26 {+-} 3 km s{sup -1}, which is larger than the locally measured solar motion of 12 km s{sup -1}. This larger offset reconciles our value for V{sub c} with recent claims that V{sub c} {approx}> 240 km s{sup -1}. Combining our results with other data, we find that the Milky Way's dark-halo mass within the virial radius is {approx}8 Multiplication-Sign 10{sup 11} M {sub Sun }.

Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Allende Prieto, Carlos; Meszaros, Szabolcs [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Bizyaev, Dmitry; Ebelke, Garrett L.; Malanushenko, Elena; Malanushenko, Viktor [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Da Costa, Luiz N.; Girardi, Leo; Maia, Marcio A. G. [Laboratorio Interinstitucional de e-Astronomia-LIneA, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ 20921-400 (Brazil); Cunha, Katia [Observatorio Nacional, Rio de Janeiro, RJ 20921-400 (Brazil); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS 20, Cambridge, MA 02138 (United States); Frinchaboy, Peter M. [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Garcia Perez, Ana Elia; Hearty, Fred R.; Majewski, Steven R.; Nidever, David L. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Holtzman, Jon, E-mail: bovy@ias.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); and others

2012-11-10T23:59:59.000Z

383

Design of passively aerated compost piles: Vertical air velocities between the pipes  

Science Conference Proceedings (OSTI)

Passively aerated compost piles are built on a base of porous materials, such as straw or wood chips, in which perforated air supply pipes are distributed. The piles are not turned during composting, nor is forced-aeration equipment used, which significantly reduces the operating and capital expenses associated with these piles. Currently, pile configurations and materials are worked out by trial and error. Fundamentally based design procedures are difficult to develop because the natural convection air flow rate is not explicitly known, but rather is closely coupled with the pile temperature. This paper develops a mathematical model to analytically determine the maximum upward air flow velocity over an air supply pipe and the drop in vertical velocity away from the pipe. This model has one dimensionless number, dependent on the pile and base properties, which fully characterizes the velocity profile between the pipes. 9 refs., 4 figs., 1 tab.

Lynch, N.J.; Cherry, R.S. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1996-09-01T23:59:59.000Z

384

Doppler cooling with coherent trains of laser pulses and a tunable velocity comb  

SciTech Connect

We explore the possibility of decelerating and Doppler cooling an ensemble of two-level atoms by a coherent train of short, nonoverlapping laser pulses. We derive analytical expressions for mechanical force exerted by the train. In frequency space the force pattern reflects the underlying frequency comb structure. The pattern depends strongly on the ratio of the atomic lifetime to the repetition time between the pulses and pulse area. For example, in the limit of short lifetimes, the frequency-space peaks of the optical force wash out. We propose to tune the carrier-envelope offset frequency to follow the Doppler-shifted detuning as atoms decelerate; this leads to compression of atomic velocity distribution about comb teeth and results in a ''velocity comb''--a series of narrow equidistant peaks in the velocity space.

Ilinova, Ekaterina; Ahmad, Mahmoud; Derevianko, Andrei [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

2011-09-15T23:59:59.000Z

385

A Hypothetical Burning-Velocity Formula for Very Lean Hydrogen-Air Mixtures  

SciTech Connect

Very lean hydrogen-air mixtures experience strong diffusive-thermal types of cellular instabilities that tend to increase the laminar burning velocity above the value that applies to steady, planar laminar flames that are homogeneous in transverse directions. Flame balls constitute an extreme limit of evolution of cellular flames. To account qualitatively for the ultimate effect of diffusive-thermal instability, a model is proposed in which the flame is a steadily propagating, planar, hexagonal, close-packed array of flame balls, each burning as if it were an isolated, stationary, ideal flame ball in an infinite, quiescent atmosphere. An expression for the laminar burning velocity is derived from this model, which theoretically may provide an upper limit for the experimental burning velocity.

Williams, Forman; Williams, Forman A; Grcar, Joseph F

2008-06-30T23:59:59.000Z

386

Acoustic Doppler Current Profiler Surveys of Velocity Downstream of Albeni Falls Dam  

DOE Green Energy (OSTI)

The U.S. Army Corps of Engineers (USACE), Seattle District, is studying the potential to locate fish bypass systems at Albeni Falls Dam. The USACE requested Pacific Northwest National Laboratory (PNNL) to survey velocity magnitude and direction in the dam tailrace. The empirical data collected will be used to support future numerical modeling, physical modeling, and evaluation of fish bypass system alternatives. In May 2010, PNNL conducted velocity surveys of the Albeni Falls Dam using a boat-mounted acoustic Doppler current profiler. The surveys were conducted over three days (May 25 through 27). During the survey period, total river discharge at the dam varied between 30.2 and 31.0 kcfs. A small amount of spill discharge, 2 kcfs, was present on two days (May 26 and 27). This report presents data plots showing measured velocity direction and magnitude averaged over the entire depth and over 5-ft depth increments from 5 to 30 ft.

Perkins, William A.; Titzler, P. Scott; Richmond, Marshall C.; Serkowski, John A.; Kallio, Sara E.; Bellgraph, Brian J.

2010-09-30T23:59:59.000Z

387

Seismic velocity structure and microearthquake source properties at The Geysers, California, geothermal area  

DOE Green Energy (OSTI)

The method of progressive hypocenter-velocity inversion has been extended to incorporate S-wave arrival time data and to estimate S-wave velocities in addition to P-wave velocities. S-wave data to progressive inversion does not completely eliminate hypocenter-velocity tradeoffs, but they are substantially reduced. Results of a P and S-wave progressive hypocenter-velocity inversion at The Geysers show that the top of the steam reservoir is clearly defined by a large decrease of V/sub p//V/sub s/ at the condensation zone-production zone contact. The depth interval of maximum steam production coincides with minimum observed V/sub p//V/sub s/, and V/sub p//V/sub s/ increses below the shallow primary production zone suggesting that reservoir rock becomes more fluid saturated. The moment tensor inversion method was applied to three microearthquakes at The Geysers. Estimated principal stress orientations were comparable to those estimated using P-wave firstmotions as constraints. Well constrained principal stress orientations were obtained for one event for which the 17 P-first motions could not distinguish between normal-slip and strike-slip mechanisms. The moment tensor estimates of principal stress orientations were obtained using far fewer stations than required for first-motion focal mechanism solutions. The three focal mechanisms obtained here support the hypothesis that focal mechanisms are a function of depth at The Geysers. Progressive inversion as developed here and the moment tensor inversion method provide a complete approach for determining earthquake locations, P and S-wave velocity structure, and earthquake source mechanisms.

O'Connell, D.R.

1986-12-01T23:59:59.000Z

388

Moment preserving adaptive particle weights using octree velocity distributions for PIC simulations  

SciTech Connect

The ratio of computational to physical particles is of primary concern to statistical particle based simulations such as DSMC and PIC. An adaptive computational particle weight algorithm is presented that conserves mass, momentum, and energy. This algorithm is then enhanced with an octree adaptive mesh in velocity space to mitigate artificial thermalization. The new octree merge is compared to a merge that randomly selects merge partners for a bi-Maxwellian velocity distribution. Results for crossing beams in a fixed potential well along with an electrostatic PIC version with and without MCC collisions based ionizing breakdown show the advantages of the merge algorithm to both fixed particle weights and randomly selected merge partners.

Martin, Robert Scott; Cambier, Jean-Luc [ERC Inc. (United States); Spacecraft Propulsion Branch, Air Force Research Laboratory, Edwards AFB, CA 93524 (United States)

2012-11-27T23:59:59.000Z

389

Nonlinear pulse propagation and phase velocity of laser-driven plasma waves  

Science Conference Proceedings (OSTI)

Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the energy gain and efficiency of laser-plasma accelerators that use a uniform plasma profile.

Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

2011-03-25T23:59:59.000Z

390

The presence of interstellar turbulence could explain the velocity flattening in galaxies  

E-Print Network (OSTI)

Expanding our previous work on turbulent whirls [1] we have uncovered a similarity within the similarity shared by intense vortices. Using the new information we compress the tangential velocity profiles of a diverse set of vortices into one and thus identify those that belong to the same genus. Examining the Laser Doppler Anemometer (LDA) results of mechanically produced vortices and radar data of several tropical cyclones, we find that the uplift and flattening effect of tangential velocity is a consequence of turbulence. Reasoning by analogy we conclude that turbulence in the interstellar medium could indeed introduce a flattening effect in the galactic rotation curves.

Vatistas, Georgios H

2010-01-01T23:59:59.000Z

391

A 4-spot time-of-flight anemometer for small centrifugal compressor velocity measurements  

SciTech Connect

The application of laser anemometry techniques in turbomachinery facilities is a challenging dilemma requiring an anemometer system with special qualities. Here, we describe the use of a novel laser anemometry technique applied to a small 4.5 kg/s, 4:1 pressure ratio centrifugal compressor. Sample velocity profiles across the blade pitch are presented for a single location along the rotor. The results of the intra-blade passage velocity measurements will ultimately be used to verify CFD 3-D viscous code predictions.

Wernet, M.P.; Skoch, G.J.

1992-07-01T23:59:59.000Z

392

Velocity and Timing of Multiple Spherically Converging Shock Waves in Liquid Deuterium  

Science Conference Proceedings (OSTI)

The fuel entropy and required drive energy for an inertial confinement fusion implosion are set by a sequence of shocks that must be precisely timed to achieve ignition. This Letter reports measurements of multiple spherical shock waves in liquid deuterium that facilitate timing inertial confinement fusion shocks to the required precision. These experiments produced the highest shock velocity observed in liquid deuterium (U{sub s}=135 km/s at {approx}2500 GPa) and also the first observation of convergence effects on the shock velocity. Simulations model the shock-timing results well when a nonlocal transport model is used in the coronal plasma.

Boehly, T. R.; Goncharov, V. N.; Seka, W.; Hu, S. X.; Marozas, J. A. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Barrios, M. A.; Celliers, P. M.; Hicks, D. G.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Meyerhofer, D. D. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Departments of Mechanical Engineering and Physics, University of Rochester, Rochester, New York 14623 (United States)

2011-05-13T23:59:59.000Z

393

A Sensor-based Long Baseline Position and Velocity Navigation Filter for Underwater Vehicles  

E-Print Network (OSTI)

This paper presents a novel Long Baseline (LBL) position and velocity navigation filter for underwater vehicles based directly on the sensor measurements. The solution departs from previous approaches as the range measurements are explicitly embedded in the filter design, therefore avoiding inversion algorithms. Moreover, the nonlinear system dynamics are considered to their full extent and no linearizations are carried out whatsoever. The filter error dynamics are globally asymptotically stable (GAS) and it is shown, under simulation environment, that the filter achieves similar performance to the Extended Kalman Filter (EKF) and outperforms linear position and velocity filters based on algebraic estimates of the position obtained from the range measurements.

Batista, Pedro; Oliveira, Paulo

2010-01-01T23:59:59.000Z

394

Group velocity of extraordinary waves in superdense magnetized quantum plasma with spin-1/2 effects  

Science Conference Proceedings (OSTI)

Based on the one component plasma model, a new dispersion relation and group velocity of elliptically polarized extraordinary electromagnetic waves in a superdense quantum magnetoplasma are derived. The group velocity of the extraordinary wave is modified due to the quantum forces and magnetization effects within a certain range of wave numbers. It means that the quantum spin-1/2 effects can reduce the transport of energy in such quantum plasma systems. Our work should be of relevance for the dense astrophysical environments and the condensed matter physics.

Li Chunhua; Ren Haijun; Yang Weihong [Department of Modern Physics, University of Science and Technology of China, 230026 Hefei (China); Wu Zhengwei [Department of Modern Physics, University of Science and Technology of China, 230026 Hefei (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2012-12-15T23:59:59.000Z

395

Method for establishing high permeability flow path between boreholes  

SciTech Connect

A method for linking adjacent boreholes in a subterranean formation, particularly in a coal gasification array, by firing a high velocity terradynamic projectile from one borehole to the other.

Dow, Jerome P. (Pleasanton, CA)

1978-01-01T23:59:59.000Z

396

Deposition Velocities of Newtonian and Non-Newtonian Slurries in Pipelines  

SciTech Connect

The WTP pipe plugging issue, as stated by the External Flowsheet Review Team (EFRT) Executive Summary, is as follows: “Piping that transports slurries will plug unless it is properly designed to minimize this risk. This design approach has not been followed consistently, which will lead to frequent shutdowns due to line plugging.” A strategy was employed to perform critical-velocity tests on several physical simulants. Critical velocity is defined as the point where a stationary bed of particles deposits on the bottom of a straight horizontal pipe during slurry transport operations. Results from the critical velocity testing provide an indication of slurry stability as a function of fluid rheological properties and transport conditions. The experimental results are compared to the WTP design guide on slurry transport velocity in an effort to confirm minimum waste velocity and flushing velocity requirements as established by calculations and critical line velocity correlations in the design guide. The major findings of this testing is discussed below. Experimental results indicate that the use of the Oroskar and Turian (1980) correlation in the design guide is conservative—Slurry viscosity has a greater affect on particles with a large surface area to mass ratio. The increased viscous forces on these particles result in a decrease in predicted critical velocities from this traditional industry derived equations that focus on particles large than 100 ?m in size. Since the Hanford slurry particles generally have large surface area to mass ratios, the reliance on such equations in the Hall (2006) design guide is conservative. Additionally, the use of the 95% percentile particle size as an input to this equation is conservative. However, test results indicate that the use of an average particle density as an input to the equation is not conservative. Particle density has a large influence on the overall result returned by the correlation. Lastly, the viscosity correlation used in the WTP design guide has been shown to be inaccurate for Hanford waste feed materials. The use of the Thomas (1979) correlation in the design guide is not conservative—In cases where 100% of the particles are smaller than 74 ?m or particles are considered to be homogeneous due to yield stress forces suspending the particles the homogeneous fraction of the slurry can be set to 100%. In such cases, the predicted critical velocity based on the conservative Oroskar and Turian (1980) correlation is reduced to zero and the design guide returns a value from the Thomas (1979) correlation. The measured data in this report show that the Thomas (1979) correlation predictions often fall below that measured experimental values. A non-Newtonian deposition velocity design guide should be developed for the WTP— Since the WTP design guide is limited to Newtonian fluids and the WTP expects to process large quantities of such materials, the existing design guide should be modified address such systems. A central experimental finding of this testing is that the flow velocity required to reach turbulent flow increases with slurry rheological properties due to viscous forces dampening the formation of turbulent eddies. The flow becomes dominated by viscous forces rather than turbulent eddies. Since the turbulent eddies necessary for particle transport are not present, the particles will settle when crossing this boundary called the transitional deposition boundary. This deposition mechanism should be expected and designed for in the WTP.

Poloski, Adam P.; Adkins, Harold E.; Abrefah, John; Casella, Andrew M.; Hohimer, Ryan E.; Nigl, Franz; Minette, Michael J.; Toth, James J.; Tingey, Joel M.; Yokuda, Satoru T.

2009-03-25T23:59:59.000Z

397

Effects of Wave Breaking on the Near-Surface Profiles of Velocity and Turbulent Kinetic Energy  

Science Conference Proceedings (OSTI)

A theoretical model for the near-surface velocity profile in the presence of breaking waves is presented. Momentum is accumulated by growing waves and is released upon wave breaking. In effect, such a transition is a process involving a time-...

Arne Melsom; Øyvind SÆtra

2004-02-01T23:59:59.000Z

398

The mean velocity of two-state models of molecular motor  

E-Print Network (OSTI)

The motion of molecular motor is essential to the biophysical functioning of living cells. In principle, this motion can be regraded as a multiple chemical states process. In which, the molecular motor can jump between different chemical states, and in each chemical state, the motor moves forward or backward in a corresponding potential. So, mathematically, the motion of molecular motor can be described by several coupled one-dimensional hopping models or by several coupled Fokker-Planck equations. To know the basic properties of molecular motor, in this paper, we will give detailed analysis about the simplest cases: in which there are only two chemical states. Actually, many of the existing models, such as the flashing ratchet model, can be regarded as a two-state model. From the explicit expression of the mean velocity, we find that the mean velocity of molecular motor might be nonzero even if the potential in each state is periodic, which means that there is no energy input to the molecular motor in each of the two states. At the same time, the mean velocity might be zero even if there is energy input to the molecular motor. Generally, the velocity of molecular motor depends not only on the potentials (or corresponding forward and backward transition rates) in the two states, but also on the transition rates between the two chemical states.

Yunxin Zhang

2010-07-10T23:59:59.000Z

399

Velocity-Dependent Friction and Diffusion for Grains in Neutral Gases, Dusty Plasmas and Active Systems  

E-Print Network (OSTI)

A self-consistent and universal description of friction and diffusion for Brownian particles (grains) in different systems, as a gas with Boltzmann collisions, dusty plasma with ion absorption by grains, and for active particles (e.g., cells in biological systems) is suggested on the basis of the appropriate Fokker-Planck equation. Restrictions for application of the Fokker-Planck equation to the problem of velocity-dependent friction and diffusion coefficients are found. General description for this coefficient is formulated on the basis of master equation. Relation of the diffusion coefficient in the coordinate and velocity spaces is found for active (capable to transfer momentum to the ambient media) and passive particles in the framework of the Fokker-Planck equation. The problem of anomalous space diffusion is formulated on the basis of the appropriate probability transition (PT) function. The method of partial differentiation is avoided to construct the correct probability distributions for arbitrary distances, what is important for applications to different stochastic problems. Generale equation for time-dependent PT function is formulated and discussed. Generalized friction in the velocity space is determined and applied to describe the friction force itself as well as the drag force in the case of a non-zero driven ion velocity in plasmas. The negative friction due to ion scattering on grains exists and can be realized for the appropriate experimental conditions.

S. A. Trigger; G. J. F. van Heijst; P. P. J. M. Schram

2004-01-19T23:59:59.000Z

400

Velocity-Dependent Friction and Diffusion for Grains in Neutral Gases, Dusty Plasmas and Active Systems  

E-Print Network (OSTI)

A self-consistent and universal description of friction and diffusion for Brownian particles (grains) in different systems, as a gas with Boltzmann collisions, dusty plasma with ion absorption by grains, and for active particles (e.g., cells in biological systems) is suggested on the basis of the appropriate Fokker-Planck equation. Restrictions for application of the Fokker-Planck equation to the problem of velocity-dependent friction and diffusion coefficients are found. General description for this coefficient is formulated on the basis of master equation. Relation of the diffusion coefficient in the coordinate and velocity spaces is found for active (capable to transfer momentum to the ambient media) and passive particles in the framework of the Fokker-Planck equation. The problem of anomalous space diffusion is formulated on the basis of the appropriate probability transition (PT) function. The method of partial differentiation is avoided to construct the correct probability distributions for arbitrary distances, what is important for applications to different stochastic problems. Generale equation for time-dependent PT function is formulated and discussed. Generalized friction in the velocity space is determined and applied to describe the friction force itself as well as the drag force in the case of a non-zero driven ion velocity in plasmas. The negative friction due to ion scattering on grains exists and can be realized for the appropriate experimental conditions.

S. A. Trigger; G. J. F. Van Heijst; P. P. J. M. Schram

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Property:Current Velocity Range(m/s) | Open Energy Information  

Open Energy Info (EERE)

Velocity Range(m/s) Velocity Range(m/s) Jump to: navigation, search Property Name Current Velocity Range(m/s) Property Type String Pages using the property "Current Velocity Range(m/s)" Showing 25 pages using this property. (previous 25) (next 25) 1 1.5-ft Wave Flume Facility + 0.0 + 10-ft Wave Flume Facility + 0.0 + 11-ft Wave Flume Facility + 0.0 + 2 2-ft Flume Facility + 0.0 + 3 3-ft Wave Flume Facility + 0.0 + 5 5-ft Wave Flume Facility + 0.0 + 6 6-ft Wave Flume Facility + 0.0 + A Alden Large Flume + 3.2 + Alden Small Flume + 0.0 + Alden Wave Basin + 0.0 + B Breakwater Research Facility + 0.0 + C Carderock Maneuvering & Seakeeping Basin + 0.0 + Carderock Tow Tank 2 + 0.0 + Carderock Tow Tank 3 + 0.0 + Chase Tow Tank + 0.0 + Coastal Harbors Modeling Facility + 0.0 +

402

Average crack front velocity during subcritical fracture propagation in a heterogeneous medium  

E-Print Network (OSTI)

the free energy, and thus the energy barrier, via numerous competing mech- anisms like stress corrosion speed of crack growth with increasing G; a weak stress- sensitive regime II follows where transportAverage crack front velocity during subcritical fracture propagation in a heterogeneous medium

Ampuero, Jean Paul

403

Cumulonimbus Vertical Velocity Events in GATE. Part II: Synthesis and Model Core Structure  

Science Conference Proceedings (OSTI)

The properties of convective drafts and cores are presented in Part I. By our definition a convective updraft must have a positive vertical velocity for 0.5 km, and exceed 0.5 m s?1 for 1 s; a convective updraft core must exceed 1 m s?1 for 0.5 ...

E. J. Zipser; M. A. LeMone

1980-11-01T23:59:59.000Z

404

On physical interpretation of two dimensional time-correlations regarding time delay velocities and eddy shaping  

SciTech Connect

Time delay estimation (TDE) techniques are frequently used to estimate the flow velocity from fluctuating measurements. Tilted structures carried by the flow lead to misinterpretation of the time delays in terms of velocity direction and amplitude. It affects TDE measurements from probes, and is also intrinsically important for beam emission spectroscopy and gas puff imaging measurements. Local eddy shapes estimated from 2D fluctuating field are necessary to gain a more accurate flow estimate from TDE, as illustrated by Langmuir probe array measurements. A least square regression approach is proposed to estimate both flow field and shaping parameters. The technique is applied to a test case built from numerical simulation of interchange fluctuations. The local eddy shape does not only provide corrections for the velocity field but also quantitative information about the statistical interaction mechanisms between local eddies and E Multiplication-Sign B flow shear. The technique is then tested on gaz puff imaging data collected at the edge of EAST tokamak plasmas. It is shown that poloidal asymmetries of the fluctuation fields-velocity and eddy shape-are consistent at least qualitatively with a ballooning type of turbulence immersed in a radially sheared equilibrium flow.

Fedorczak, N. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Manz, P. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); Max-Planck-Institut feur Plasmaphysik, Association Euratom-IPP, 85748Garching (Germany); Thakur, S. C.; Xu, M.; Tynan, G. R. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); Xu, G. S.; Liu, S. C. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2012-12-15T23:59:59.000Z

405

A California Statewide Three-Dimensional Seismic Velocity Model from Both Absolute and Differential Times  

E-Print Network (OSTI)

A California Statewide Three-Dimensional Seismic Velocity Model from Both Absolute and Differential of the California crust and uppermost mantle using a regional-scale double-difference tomography algorithm. We begin using S picks from both the Southern California Seismic Network and USArray, assuming a starting model

Shearer, Peter

406

Lithospheric Velocity Structure of the Anatolain plateau-Caucasus-Caspian Regions  

SciTech Connect

Anatolian Plateau-Caucasus-Caspian region is an area of complex structure accompanied by large variations in seismic wave velocities. Despite the complexity of the region little is known about the detailed lithospheric structure. Using data from 29 new broadband seismic stations in the region, a unified velocity structure is developed using teleseismic receiver functions and surface waves. Love and Rayleigh surface waves dispersion curves have been derived from event-based analysis and ambient-noise correlation. We jointly inverted the receiver functions with the surface wave dispersion curves to determine absolute shear wave velocity and important discontinuities such as sedimentary layer, Moho, lithospheric-asthenospheric boundary. We combined these new station results with Eastern Turkey Seismic Experiment results (29 stations). Caspian Sea and Kura basin underlained by one of the thickest sediments in the world. Therefore, short-period surface waves are observed to be very slow. The strong crustal multiples in receiver functions and the slow velocities in upper crust indicate the presence of thick sedimentary unit (up to 20 km). Crustal thickness varies from 34 to 52 km in the region. The thickest crust is in Lesser Caucasus and the thinnest is in the Arabian Plate. The lithospheric mantle in the Greater Caucasus and the Kura depression is faster than the Anatolian Plateau and Lesser Caucasus. This possibly indicates the presence of cold lithosphere. The lower crust is slowest in the northeastern part of the Anatolian Plateau where Holocene volcanoes are located.

Gok, R; Mellors, R J; Sandvol, E; Pasyanos, M; Hauk, T; Yetirmishli, G; Teoman, U; Turkelli, N; Godoladze, T; Javakishvirli, Z

2009-04-15T23:59:59.000Z

407

Wind Velocities at the Chajnantor and Mauna Kea Sites and the Effect on MMA Pointing  

E-Print Network (OSTI)

Wind Velocities at the Chajnantor and Mauna Kea Sites and the Effect on MMA Pointing M.A. Holdaway email: (mholdawa, sfoster, demerson, jcheng, fschwab)@nrao.edu August 9, 1996 Abstract We analyze wind April 1996 for the purposes of understanding the effects of the winds on pointing errors. Both

Groppi, Christopher

408

Direct detection and solar capture of dark matter with momentum and velocity dependent elastic scattering  

E-Print Network (OSTI)

We explore the momentum and velocity dependent elastic scattering between the dark matter (DM) particles and the nuclei in detectors and the Sun. In terms of the non-relativistic effective theory, we phenomenologically discuss ten kinds of momentum and velocity dependent DM-nucleus interactions and recalculate the corresponding upper limits on the spin-independent DM-nucleon scattering cross section from the current direct detection experiments. The DM solar capture rate is calculated for each interaction. Our numerical results show that the momentum and velocity dependent cases can give larger solar capture rate than the usual contact interaction case for almost the whole parameter space. On the other hand, we deduce the Super-Kamiokande's constraints on the solar capture rate for eight typical DM annihilation channels. In contrast to the usual contact interaction, the Super-Kamiokande and IceCube experiments can give more stringent limits on the DM-nucleon elastic scattering cross section than the current direct detection experiments for several momentum and velocity dependent DM-nucleus interactions. In addition, we investigate the mediator mass's effect on the DM elastic scattering cross section and solar capture rate.

Wan-Lei Guo; Zheng-Liang Liang; Yue-Liang Wu

2013-05-04T23:59:59.000Z

409

Shock initiation studies of low density HMX using electromagnetic particle velocity and PVDF stress gauges  

Science Conference Proceedings (OSTI)

Magnetic particle velocity and PVDF stress rate gauges have been used to measure the shock response of low density octotetramethylene tetranitramine (HMX) (1.24 &/cm{sup 3}). In experiments done at LANL, magnetic particle velocity gauges were located on both sides of the explosive. In nearly identical experiments done at SNL, PVDF stress rate gauges were located at the same positions so both particle velocity and stress histories were obtained for a particular experimental condition. Unreacted Hugoniot data were obtained and an EOS was developed by combining methods used by Hayes, Sheffield and Mitchell (for describing the Hugoniot of HNS at various densities) with Hermann`s P-{alpha} model. Using this technique, it is only necessary to know some thermodynamic constants or the Hugoniot of the initially solid material and the porous material sound speed to obtain accurate unreacted Hugoniots for the porous explosive. Loading and reaction paths were established in the stress-particle velocity plane for some experimental conditions. This information was used to determine a global reaction rate of {approx} 0.13 {mu}s{sup {minus}1} for porous HMX shocked to 0.8 GPa. At low input stresses the transmitted wave profiles had long rise times (up to 1 {mu}s) due to the compaction processes.

Sheffield, S.A.; Gustavsen, R.L.; Alcon, R.R. [Los Alamos National Lab., NM (United States); Graham, R.A.; Anderson, M.U. [Sandia National Labs., Albuquerque, NM (United States)

1993-09-01T23:59:59.000Z

410

The Mean and Near-Inertial Velocity Fields in a Warm-Core Ring  

Science Conference Proceedings (OSTI)

Velocity and temperature profiles collected in warm-core ring 82-I in January 1983 are used to describe the mean and fluctuating fields of the ring. The ring was relatively small, containing no Sargasso See water. Its signature vanished below 600 ...

Eric Kunze

1986-08-01T23:59:59.000Z

411

On Energy Flux and Group Velocity of Waves in Baroclinic Flows  

Science Conference Proceedings (OSTI)

A modified energy flux is defined by adding a nondivergent term that involves ? to the traditional energy flux. The resultant flux, when normalized by the total eddy energy, is exactly equal to the group velocity of Rossby waves on a ? plane with ...

Edmund K. M. Chang; Isidoro Orlanski

1994-12-01T23:59:59.000Z

412

Velocities of deep water reservoir sands De-hua Han, University of Houston  

E-Print Network (OSTI)

and shale, which is not focus for this study. Sorting HP Shale ShallowDeep Sorting HP Shale Sorting HP Shale sands. Grain density is 2.65 gm/cc, typical for clean sands. Measured gas permeability ranged from 100 have revealed gradual effect of clay content on porosity and velocity of shaly sands and sandy shales

413

Increase of shear wave velocity before the 1998 eruption of Merapi volcano (Indonesia)  

E-Print Network (OSTI)

Increase of shear wave velocity before the 1998 eruption of Merapi volcano (Indonesia) U. Wegler,1 of the edifice of Merapi volcano (Java, Indonesia) before its eruption in 1998 by analyzing multiply scattered eruption of Merapi volcano (Indonesia), Geophys. Res. Lett., 33, L09303, doi:10.1029/2006GL025928. 1

Snieder, Roel

414

Bathymetry estimation using drifter-based velocity measurements on the Kootenai River, ID, USA  

Science Conference Proceedings (OSTI)

Velocity measurements from drifter GPS records are used in an ensemble-based data assimilation technique to extract the river bathymetry. The method is tested on a deep meandering reach and a shallow braided reach of the Kootenai River in Idaho, ...

Kyle C. Landon; Greg W. Wilson; H. Tuba Özkan-Haller; Jamie H. MacMahan

415

Reconstructing Basin-Scale Eulerian Velocity Fields from Simulated Drifter Data  

Science Conference Proceedings (OSTI)

A single-layer, reduced-gravity, double-gyre primitive equation model in a 2000 km × 2000 km square domain is used to test the accuracy and sensitivity of time-dependent Eulerian velocity fields reconstructed from numerically generated drifter ...

M. Toner; A. D. Kirwan Jr.; B. L. Lipphardt; A. C. Poje; C. K. R. T. Jones; C. E. Grosch

2001-05-01T23:59:59.000Z

416

Uncertainty in a Path-averaged Measurement of the Friction Velocity u*  

Science Conference Proceedings (OSTI)

Several electro-optical methods exist for measuring a path-averaged value of the inner scale of turbulence l0. By virtue of Monin–Obukhov similarity, in the atmospheric surface layer such l0 measurements are related to the friction velocity u* or ...

Edgar L. Andreas

1992-11-01T23:59:59.000Z

417

Mean Vertical Velocities Measured by Indian MST Radar and Comparison with Indirectly Computed Values  

Science Conference Proceedings (OSTI)

Mean vertical velocities and their variations observed with Indian mesosphere–stratosphere–troposphere (MST) radar located at Gadanki (13.5°N, 79.2°E), a tropical station in India, are presented. In this study, a comparison has been made between ...

V. V. M. Jagannadha Rao; D. Narayana Rao; M. Venkat Ratnam; K. Mohan; S. Vijaya Bhaskar Rao

2003-04-01T23:59:59.000Z

418

Velocity-jump processes with a finite number of speeds and their asymptotically parabolic nature  

E-Print Network (OSTI)

Velocity-jump processes with a finite number of speeds and their asymptotically parabolic nature-time behavior is described by a corresponding scalar diffusive equation of parabolic type, defined, alternative to the tradi- tional parabolic heat equation, which, on the contrary, mantains the inherent

Recanati, Catherine

419

Velocity Biases of Adaptive Filter Estimates in Heterodyne Doppler Lidar Measurements  

Science Conference Proceedings (OSTI)

Frequency estimates by heterodyne Doppler lidar (HDL) may result in velocity bias due to the atmospheric speckle effect and an asymmetrical power spectrum of the probing pulse, as discussed in a previous paper by Dabas et al. In this paper, it ...

Alain M. Dabas; Philippe Drobinski; Pierre H. Flamant

2000-09-01T23:59:59.000Z

420

A Photoelectric Technique for Measuring Lightning-Channel Propagation Velocities from a Mobile Laboratory  

Science Conference Proceedings (OSTI)

We have developed a device to measure lightning-channel propagation velocities. It consists of eight solid state silicon photodetectors mounted behind precision horizontal slits in the focal plane of a 50-mm lens on a 35-mm camera body. Each ...

Douglas M. Mach; W. David Rust

1989-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "high velocity sdhv" 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

Real time mass flux measurements of gas-solid suspensions at low velocities  

SciTech Connect

In previous work, measurement of the particulate mass flux was made based upon a novel electrostatic technique. A small conducting wire sensor was inserted in the flow and as each particle hit the sensor an individual pulse of current was identified. Through suitable electronic circuitry, the number of pulses in a given time were counted. This was a direct measure of the number of particle-probe collisions which was related to local particle mass flow. The technique is currently limited to monodisperse suspensions. A primary advantage of the impact counter system is that the output does not depend upon the magnitude of the actual charge transfer. As long as the pulses are sufficiently above the noise level, variations in charge transfer will not affect the measurement. For the current work, the technique was applied to vertical gas-solid flow where the fluid velocity was slightly above the particle terminal velocity. Under these conditions a sufficient signal to noise ratio was not found. The Cheng-Soo charge transfer theory indicated that the low particle-sensor impact velocity was responsible. The probe system was then modified by extracting a particulate sample isokinetically and accelerating the particles to a sufficient velocity by an area reduction in the sampling tube. With this technique the signal to noise ratio was about 12 to 1. Mass flux results are shown to compare favorably with filter collection and weighing.

Saunders, J H; Chao, B T; Soo, S L

1981-01-01T23:59:59.000Z

422

Temporal and Spatial Aspects of Velocity Variance in the Urban Surface Roughness Layer  

Science Conference Proceedings (OSTI)

Data from six urban areas in a nationwide network of sites within the surface roughness layer are examined. It is found that the average velocity variances in time, derived by averaging the conventional variances from a network of n stations, are ...

Bruce B. Hicks; Elena Novakovskaia; Ronald J. Dobosy; William R. Pendergrass III; William J. Callahan

2013-03-01T23:59:59.000Z

423

Liner velocity, current, and symmetry measurements on the 32 MEGAMP flux compression generator experiment ALT-1  

SciTech Connect

A flux compression generator pulse power system, designed, built, and fielded by a Russian team at the All Russian Scientific Research Institute of Experimental Physics (VNIIEF), was used to successfully drive an aluminum liner to velocities greater than 12 km/sec. The experiment objective was to demonstrate performance of a precision liner implosion at an Atlas current of 30 MA or greater. Diagnostics to measure liner performance were an essential part of the experiment. An experimental team from Los Alamos National Laboratory (LANL) provided a suite of diagnostics to measure liner performance. Three diagnostics were fielded: (1) A velocity interferometer (VISAR) to continuously measure the liner innersurface velocity throughout the entire range of travel, (2) Two Faraday rotation devices to measure liner current during the implosion, and, (3) Sixteen fiber optic impact pins to record liner impact time and provide axial and azimuthal symmetry information. All diagnostics performed very well. Major results are maximum current: 32.3 MA, velocity at impact: greater than 12 km/sec, symmetry: the impact pins indicated that the liner was smooth, solid, and axially symmetric upon arrival at the diagnostic package. The LANL team fabricated, installed, and recorded the three diagnostics presented here. All necessary equipment was brought to the site in Russia. The VNIIEF team fielded other diagnostics to measure machine performance. Results of machine diagnostics are reported in other presentations.

Anderson, B. G. (Brodie G.); Rodriguez, G. (George); Stokes, J. L. (John L.); Tabaka, L. J. (Leonard J.); Clark, D. A. (David A.)

2001-01-01T23:59:59.000Z

424

A Darcy law for the drift velocity in a two-phase flow model  

Science Conference Proceedings (OSTI)

This work deals with the design and numerical approximation of an Eulerian mixture model for the simulation of two-phase dispersed flows. In contrast to the more classical two-fluid or Drift-flux models, the influence of the velocity disequilibrium is ... Keywords: Bubbly flows, Chapman-Enskog expansion, Darcy law, Drift-flux, Riemann solver, Two-phase flows

H. Guillard; F. Duval

2007-05-01T23:59:59.000Z

425

ARDB-158 R. Siemann November 6, 1997 Group Velocity Dispersion in Hamamatsu Streak Camera  

E-Print Network (OSTI)

1 1 2( ) ( ) The large chromatic time delay indicates that there is a large fraction of flint glass in the objective which is a proprietary design manufactured by Nikon. Using the data for SF4 (Flint glass) from and group velocities for borosicilate (BK7) and flint (SF4) glasses (Staerk et al) #12;2 Duncan et al

426

Effect of wave boundary layer on sea-to-air dimethylsulfide transfer velocity during typhoon passage  

E-Print Network (OSTI)

: Dimethylsulfide; Sea-to-air gas transfer velocity; Wave boundary layer; Tropical cyclone; Drag coefficient in order to accurately calculate aerosol radiative forcing. The sea-to-air DMS flux depends on airside coefficient CD and roughness length z0 has been investigated over small areas of the sea or in wave tanks

Chu, Peter C.

427

A Modified Multivariate Madden–Julian Oscillation Index Using Velocity Potential  

Science Conference Proceedings (OSTI)

A new Madden–Julian oscillation (MJO) index is developed from a combined empirical orthogonal function (EOF) analysis of meridionally averaged 200-hPa velocity potential (VP200), 200-hPa zonal wind (U200), and 850-hPa zonal wind (U850). Like the ...

Michael J. Ventrice; Matthew C. Wheeler; Harry H. Hendon; Carl J. Schreck III; Chris D. Thorncroft; George N. Kiladis

2013-12-01T23:59:59.000Z

428

A HYPOTHETICAL BURNING-VELOCITY FORMULA FOR VERY LEAN HYDROGEN-AIR MIXTURES  

E-Print Network (OSTI)

1 A HYPOTHETICAL BURNING-VELOCITY FORMULA FOR VERY LEAN HYDROGEN-AIR MIXTURES by Forman A. Williams experience strong diffusive-thermal types of cellular instabilities that tend to increase the laminar burning propagating, planar, hexagonal, close-packed array of flame balls, each burning as if it were an isolated

Geddes, Cameron Guy Robinson

429

EVOLUTION OF THE VELOCITY-DISPERSION FUNCTION OF LUMINOUS RED GALAXIES: A HIERARCHICAL BAYESIAN MEASUREMENT  

SciTech Connect

We present a hierarchical Bayesian determination of the velocity-dispersion function of approximately 430,000 massive luminous red galaxies observed at relatively low spectroscopic signal-to-noise ratio (S/N {approx} 3-5 per 69 km s{sup -1}) by the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III. We marginalize over spectroscopic redshift errors, and use the full velocity-dispersion likelihood function for each galaxy to make a self-consistent determination of the velocity-dispersion distribution parameters as a function of absolute magnitude and redshift, correcting as well for the effects of broadband magnitude errors on our binning. Parameterizing the distribution at each point in the luminosity-redshift plane with a log-normal form, we detect significant evolution in the width of the distribution toward higher intrinsic scatter at higher redshifts. Using a subset of deep re-observations of BOSS galaxies, we demonstrate that our distribution-parameter estimates are unbiased regardless of spectroscopic S/N. We also show through simulation that our method introduces no systematic parameter bias with redshift. We highlight the advantage of the hierarchical Bayesian method over frequentist 'stacking' of spectra, and illustrate how our measured distribution parameters can be adopted as informative priors for velocity-dispersion measurements from individual noisy spectra.

Shu Yiping; Bolton, Adam S.; Dawson, Kyle S.; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Schlegel, David J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Wake, David A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); Brinkmann, Jon [Apache Point Observatory, Apache Point Road, P.O. Box 59, Sunspot, NM 88349 (United States); Weaver, Benjamin A., E-mail: yiping.shu@utah.edu, E-mail: bolton@astro.utah.edu [Center for Cosmology and Particle Physics, New York University, NY 10003 (United States)

2012-04-15T23:59:59.000Z

430

Proceedings: Evolution of Large Scale Structure --Garching, August 1998 THE EFAR PECULIAR VELOCITY FIELD  

E-Print Network (OSTI)

determinations, and used to determine the peculiar velocities (PV) of the clusters. We find that the mean detected lo­ cally (Lynden­Bell et al. 1988), and therefore is a sensitive test of cosmo­ logical models and bulge components of the galaxies are also available, allow­ ing a reliable morphological classifi

Saglia, Roberto P.

431

Measurements of the bulk and interfacial velocity profiles in oscillating Newtonian and Maxwellian fluids  

E-Print Network (OSTI)

We present the dynamic velocity profiles of a Newtonian fluid (glycerol) and a viscoelastic Maxwell fluid (CPyCl/NaSal in water) driven by an oscillating pressure gradient in a vertical cylindrical pipe. The frequency range explored has been chosen to include the first three resonance peaks of the dynamic permeability of the viscoelastic fluid / pipe system. Three different optical measurement techniques have been employed. Laser Doppler Anemometry has been used to measure the magnitude of the velocity at the centre of the liquid column. Particle Image Velocimetry and Optical Deflectometry are used to determine the velocity profiles at the bulk of the liquid column and at the liquid--air interface respectively. The velocity measurements in the bulk are in good agreement with the theoretical predictions of a linear theory. The results, however, show dramatic differences in the dynamic behaviour of Newtonian and viscoelastic fluids, and demonstrate the importance of resonance phenomena in viscoelastic fluid flows, biofluids in particular, in confined geometries.

M. Torralba; J. R. Castrejon-Pita; A. A. Castrejon-Pita; G. Huelsz; J. A. del Rio; J. Ortin

2005-05-10T23:59:59.000Z

432

Fall Velocities of Hydrometeors in the Atmosphere: Refinements to a Continuous Analytical Power Law  

Science Conference Proceedings (OSTI)

This paper extends the previous research of the authors on the unified representation of fall velocities for both liquid and crystalline particles as a power law over the entire size range of hydrometeors observed in the atmosphere. The power-law ...

Vitaly I. Khvorostyanov; Judith A. Curry

2005-12-01T23:59:59.000Z

433

A study of swirl and axial velocity profile effects on orifice flowmeters  

E-Print Network (OSTI)

The objective of this study is to measure the response of the orifice meter to known upstream flow field disturbances generated by a concentric tube flow conditioner and a vane-type swirl generator. These disturbances are characterized by flan measuring the axial and tangential velocity profiles at the upstream tap with no orifice plate present. Two different flow rates are examined which correspond to Reynolds numbers of 91,100 and 120,000 in a 50.8 mm diameter pipe. Eight orifice plates with [ ] ratios of 0.43, 0.45, 0.484, 0.55, 0.6, 0.65, 0.7 and 0.726 are studied at both flow rates. The response of each orifice meter to the disturbance is measured by determining the axial pressure distribution near the orifice plate, and by determining the discharge coefficient. The axial momentum distribution is quantified by calculating the second order moment of axial momentum (91 2[U]) from the velocity profile data. Swirl is quantified by determining the centripetal acceleration flux of the flow, also from the velocity profile data. Surface fits indicating the variation of discharge coefficient as a function of P ratio and 9i2[U] or swirl number are developed. These are useful in evaluating variations in the discharge coefficient for flows where the inlet velocity profile has been measured.

Hauglie, Jayden Edward

1994-01-01T23:59:59.000Z

434

Rapid Cardiovascular Flow Quantitation Using Slice-Selective Spiral Fourier Velocity Encoding J. L. Carvalho1  

E-Print Network (OSTI)

by gridding and inverse Fourier transform, converting the acquired data S(kx,ky,kv,t) to S(x,y,kv,t). A region. Carvalho1 , K. S. Nayak1 1 Department of Electrical Engineering, University of Southern California, Los. The use of FVE instead of PC makes it possible to resolve the full velocity distribution within each voxel

Southern California, University of

435

On the Group-Velocity Property for Wave-Activity Conservation Laws  

Science Conference Proceedings (OSTI)

The density and the flux of wave-activity conservation laws are generally required to satisfy the group-velocity property: under the WKB approximation (i.e., for nearly monochromatic small-amplitude waves in a slowly varying medium), the flux ...

J. Vanneste; T. G. Shepherd

1998-03-01T23:59:59.000Z

436

An Improved Approach to Calculating Terminal Velocities of Plate-like Crystals and Graupel  

Science Conference Proceedings (OSTI)

Measurements of 461 planar crows and 312 graupel reported by Kajikawa have been used to develop equations for calculating the terminal velocity and mass of lump and conical graupel and of planar crystals of a variety of shapes and degrees of ...

Andrew J. Heymsfield; Masahiro Kajikawa

1987-04-01T23:59:59.000Z

437

A high-resolution two-dimensional imaging velocimeter  

Science Conference Proceedings (OSTI)

Velocity interferometers are typically used to measure velocities of surfaces at a single point or along an imaged line as a function of time. We describe an optical arrangement that enables high-resolution measurements of the two-dimensional velocity field across a shock front or shocked interface. The technique is employed to measure microscopic fluctuations in shock fronts that have passed through materials being considered as ablators for indirect-drive inertial confinement fusion. With picosecond time resolution the instrument captures velocity modes with wavelengths as short as 2.5 {mu}m at a resolution of {approx}10 m/s rms on velocity fields averaging many km/s over an 800 {mu}m field of view.

Celliers, P. M.; Erskine, D. J.; Sorce, C. M.; Braun, D. G.; Landen, O. L.; Collins, G. W. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

2010-03-15T23:59:59.000Z

438

Inversion of Newberry Volcano high-resolution traveltime residuals  

SciTech Connect

Inversion of the 1984 traveltime data from the array at Newberry Crater was accomplished using a variant of the method presented by Aki and others (1973). Five-hundred-sixty-five traveltime observations for Pg and a deeper reflection, weighted by their variance estimates, were included in the inversion. Azimuths from receiver-to-source range from 80 to 280. The initial-velocity model for the inversion has four layers. The top layer, starting at the surface and extending to an elevation of 1300 meters above sea level, had a P-velocity of 2.5 km/s. There are three layers below this one, each 1500-m thick, with P-velocities of 4.0, 4.6, and 5.2 km/s. The predominant feature in the inversion result in the upper two layers (surface to 200-m below sea level), is the ring of high velocities coincident with the caldera ring-fracture system. This high-velocity ring is up to 11% faster than the average for these two layers. In these layers velocities are a few percent slower than average in the center of the caldera and range from 5 to 10% slower outside the caldera to the south, east, and north. In the third layer (-200 to 1700 m elevation), the magnitude of the high-velocity anomaly around the ring-fracture system is reduced, but the bin in the center of the caldera is nearly 9% slower than the layer average.

Stauber, D.A.

1986-01-01T23:59:59.000Z

439

A test of Einstein's theory of gravitation: Velocity distribution of low-energy particles in a spherically symmetric gravitational field  

E-Print Network (OSTI)

We propose a new test of Einstein's theory of gravitation. It concerns the velocity distribution of low-energy particles in a spherically symmetric gravitational field.

Jian-Miin Liu

2002-06-17T23:59:59.000Z

440

COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. III. VELOCITY GRADIENTS IN NON-AXISYMMETRIC ENVELOPES, INFALL, OR ROTATION?  

SciTech Connect

We present an interferometric kinematic study of morphologically complex protostellar envelopes based on observations of the dense gas tracers N{sub 2}H{sup +} and NH{sub 3}. The strong asymmetric nature of most envelopes in our sample leads us to question the common interpretation of velocity gradients as rotation, given the possibility of projection effects in the observed velocities. Several 'idealized' sources with well-ordered velocity fields and envelope structures are now analyzed in more detail. We compare the interferometric data to position-velocity (PV) diagrams of kinematic models for spherical rotating collapse and filamentary rotating collapse. For this purpose, we developed a filamentary parameterization of the rotating collapse model to explore the effects of geometric projection on the observed velocity structures. We find that most envelopes in our sample have PV structures that can be reproduced by an infalling filamentary envelope projected at different angles within the plane of the sky. The infalling filament produces velocity shifts across the envelope that can mimic rotation, especially when viewed at single-dish resolutions and the axisymmetric rotating collapse model does not uniquely describe any data set. Furthermore, if the velocities are assumed to reflect rotation, then the inferred centrifugal radii are quite large in most cases, indicating significant fragmentation potential or more likely another component to the line-center velocity. We conclude that ordered velocity gradients cannot be interpreted as rotation alone when envelopes are non-axisymmetric and that projected infall velocities likely dominate the velocity field on scales larger than 1000 AU.

Tobin, John J.; Hartmann, Lee; Bergin, Edwin [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Chiang, Hsin-Fang; Looney, Leslie W. [Department of Astronomy, University of Illinois at Champaign/Urbana, Urbana, IL 61801 (United States); Chandler, Claire J. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Maret, Sebastien [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Heitsch, Fabian, E-mail: jtobin@nrao.edu [Department of Astronomy, University of North Carolina, Chapel Hill, NC (United States)

2012-03-20T23:59:59.000Z

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441

Tracking granules on the Sun's surface and reconstructing horizontal velocity fields: I. the CST algorithm  

E-Print Network (OSTI)

Determination of horizontal velocity fields on the solar surface is crucial for understanding the dynamics of structures like mesogranulation or supergranulation or simply the distribution of magnetic fields. We pursue here the development of a method called CST for coherent structure tracking, which determines the horizontal motion of granules in the field of view. We first devise a generalization of Strous method for the segmentation of images and show that when segmentation follows the shape of granules more closely, granule tracking is less effective for large granules because of increased sensitivity to granule fragmentation. We then introduce the multi-resolution analysis on the velocity field, based on Daubechies wavelets, which provides a view of this field on different scales. An algorithm for computing the field derivatives, like the horizontal divergence and the vertical vorticity, is also devised. The effects from the lack of data or from terrestrial atmospheric distortion of the images are also briefly discussed.

M. Rieutord; T. Roudier; S. Roques; C. Ducottet

2007-07-13T23:59:59.000Z

442

Extremely low surface recombination velocities in black silicon passivated by atomic layer deposition  

Science Conference Proceedings (OSTI)

We investigate the optical and opto-electronic properties of black silicon (b-Si) nanostructures passivated with Al{sub 2}O{sub 3}. The b-Si nanostructures significantly improve the absorption of silicon due to superior anti-reflection and light trapping properties. By coating the b-Si nanostructures with a conformal layer of Al{sub 2}O{sub 3} by atomic layer deposition, the surface recombination velocity can be effectively reduced. We show that control of plasma-induced subsurface damage is equally important to achieve low interface recombination. Surface recombination velocities of S{sub eff}<13 cm/s have been measured for an optimized structure which, like the polished reference, exhibits lifetimes in the millisecond range.

Otto, Martin [Martin-Luther-University Halle-Wittenberg, mu MD Group-Institute of Physics, Heinrich-Damerow-Strasse 4, 06120 Halle (Germany); Kroll, Matthias; Kaesebier, Thomas; Tuennermann, Andreas [Friedrich-Schiller-Universitaet Jena, Institute of Applied Physics, Max-Wien-Platz 1, 07743 Jena (Germany); Salzer, Roland [Fraunhofer Institute for Mechanics of Materials Halle, Walter-Huelse-Str. 1, 06120 Halle (Germany); Wehrspohn, Ralf B. [Martin-Luther-University Halle-Wittenberg, mu MD Group-Institute of Physics, Heinrich-Damerow-Strasse 4, 06120 Halle (Germany); Fraunhofer Institute for Mechanics of Materials Halle, Walter-Huelse-Str. 1, 06120 Halle (Germany)

2012-05-07T23:59:59.000Z

443

Magnetic Resonance Flow Velocity and Temperature Mapping of a Shape Memory Polymer Foam Device  

Science Conference Proceedings (OSTI)

Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

Small IV, W; Gjersing, E; Herberg, J L; Wilson, T S; Maitland, D J

2008-10-29T23:59:59.000Z

444

Group velocity and pulse lengthening of mismatched laser pulses in plasma channels  

SciTech Connect

Analytic solutions are presented to the non-paraxial wave equation describing an ultra-short, low-power, laser pulse propagating in aplasma channel. Expressions for the laser pulse centroid motion and laser group velocity are derived, valid for matched and mismatchedpropagation in a parabolic plasma channel, as well as in vacuum, for an arbitrary Laguerre-Gaussian laser mode. The group velocity of amismatched laser pulse, for which the laser spot size is strongly oscillating, is found to be independent of propagation distance andsignificantly less than that of a matched pulse. Laser pulse lengthening of a mismatched pulse owing to laser mode slippage isexamined and found to dominate over that due to dispersive pulse spreading for sufficiently long pulses. Analytic results are shown tobe in excellent agreement with numerical solutions of the full Maxwell equations coupled to the plasma response. Implications for plasmachannel diagnostics are discussed.

Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; van Tilborg, Jeroen; Leemans, Wim

2011-07-07T23:59:59.000Z

445

Imaging earth's interior: Tomographic inversions for mantle P-wave velocity structure  

SciTech Connect

A formalism is developed for the tomographic inversion of seismic travel time residuals. The travel time equations are solved both simultaneously, for velocity model terms and corrections to the source locations, and progressively, for each set of terms in succession. The methods differ primarily in their treatment of source mislocation terms. Additionally, the system of equations is solved directly, neglecting source terms. The efficacy of the algorithms is explored with synthetic data as we perform simulations of the general procedure used to produce tomographic images of Earth's mantle from global earthquake data. The patterns of seismic heterogeneity in the mantle that would be returned reliably by a tomographic inversion are investigated. We construct synthetic data sets based on real ray sampling of the mantle by introducing spherical harmonic patterns of velocity heterogeneity and perform inversions of the synthetic data.

Pulliam, R.J.

1991-07-01T23:59:59.000Z

446

Technical Challenges in Low-velocity SRF Development ATLAS 25th Anniversary Celebration  

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

Challenges in Low-velocity SRF Development Challenges in Low-velocity SRF Development ATLAS 25th Anniversary Celebration October 22-23, 2010 Physics Division, Argonne National Laboratory Building 203, Auditorium Speaker: Mike Kelly ATLAS Energy Upgrade: Commissioned June 2009 14.5 MV in 5 meters using 7 SC Quarter-wave Cavities Superconductivity 1911 - superconductivity discovered by Kamerlingh Onnes in a sample of Hg at 4 Kelvin 1950's: - Ginsburg-Landau theory developed - 1957 - Bardeen, Cooper, and Schrieffer theory First applications such as SC magnets 1964 - SC resonators developed for accelerator applications at Stanford Leiden, ca. 1910 4 Outline Materials from: Ken Shepard, Joel Fuerst I. Some superconductivity background II. Progress in RF superconductivity

447

Effect of the Darrieus-Landau instability on turbulent flame velocity  

E-Print Network (OSTI)

Propagation of turbulent premixed flames influenced by the intrinsic hydrodynamic flame instability (the Darrieus-Landau instability) is considered in a two-dimensional case using the model nonlinear equation proposed recently. The nonlinear equation takes into account both influence of external turbulence and intrinsic properties of a flame front, such as small but finite flame thickness and realistically large density variations across the flame front. Dependence of the flame velocity on the turbulent length scale, on the turbulent intensity and on the density variations is investigated in the case of weak non-linearity and weak external turbulence. It is shown that the Darrieus-Landau instability influences the flamelet velocity considerably. The obtained results are in agreement with experimental data on turbulent burning of moderate values of the Reynolds number.

Maxim Zaytsev; Vitaliy Bychkov

2012-11-26T23:59:59.000Z

448

Velocity map imaging of HBr photodissociation in large rare gas clusters  

SciTech Connect

We have implemented the velocity map imaging technique to study clustering in the pulsed supersonic expansions of hydrogen bromide in helium, argon, and xenon. The expansions are characterized by direct imaging of the beam velocity distributions. We have investigated the cluster generation by means of UV photodissociation and photoionization of HBr molecules. Two distinct features appear in the hydrogen atom photofragment images in the clustering regime: (i) photofragments with near zero kinetic energies and (ii) ''hot'' photofragments originating from vibrationally excited HBr molecules. The origin of both features is attributed to the fragment caging by the cluster. We discuss the nature of the formed clusters based on the change of the photofragment images with the expansion parameters and on the photoionization mass spectra and conclude that single HBr molecule encompassed with rare gas ''snowball'' is consistent with the experimental observations.

Fedor, J.; Kocisek, J.; Poterya, V.; Votava, O.; Pysanenko, A.; Farnik, M. [J. Heyrovsky Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague (Czech Republic); Lipciuc, M. L. [Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (United Kingdom); Kitsopoulos, T. N. [Department of Chemistry, University of Crete, Heraklion (Greece) and Institute of Electronic Structure and Lasers, Foundation for Research and Technology, Hellas, P.O. Box 1527, 71110 Heraklion (Greece)

2011-04-21T23:59:59.000Z

449

Evaluation of the Maximum Cross-Correlation Method of Estimating Sea Surface Velocities from Sequential Satellite Images  

Science Conference Proceedings (OSTI)

We evaluate the method of estimating sea surface velocities from sequences of AVHRR and CZCS images using the maximum cross-correlation (MCC) technique. A set of synthetic images is created by advecting an AVHRR-SST field with a QG model velocity ...

Robin Tokmakian; P. Ted Strub; Julie McClean-Padman

1990-12-01T23:59:59.000Z

450

IEEE SENSORS JOURNAL, VOL. 8, NO. 7, JULY 2008 1099 Fiber-Optic Sensor for Web Velocity Measurement  

E-Print Network (OSTI)

of light from the web surface (with no physical contact), the output of the fiber-optic sensorIEEE SENSORS JOURNAL, VOL. 8, NO. 7, JULY 2008 1099 Fiber-Optic Sensor for Web Velocity Measurement Abstract--The design and development of a new fiber-optic sensor for measuring the velocity of a continuous

Pagilla, Prabhakar R.

451

Direct Measurements of Vertical-Velocity Power Spectra with the Sousy-VHF-Radar Wind Profiler System  

Science Conference Proceedings (OSTI)

We present power spectra of vertical velocities measured with the SOUSY-VHF-Radax wind profiler.over a 5-day period in October and November 1981. Most of the data consist of hourly vertical velocity profiles based on 12-rain averages, but, for ...

M. F. Larsen; J. Rutger; D. N. Holden

1987-12-01T23:59:59.000Z

452

Möbius Transformation and Einsten Velocity Addition in the Hyperbolic Geometry of Bolyai and Lobachevsky  

E-Print Network (OSTI)

In this chapter, dedicated to the 60th Anniversary of Themistocles M. Rassias, M\\"obius transformation and Einstein velocity addition meet in the hyperbolic geometry of Bolyai and Lobachevsky. It turns out that M\\"obius addition that is extracted from M\\"obius transformation of the complex disc and Einstein addition from his special theory of relativity are isomorphic in the sense of gyrovector spaces.

Abraham A. Ungar

2013-03-19T23:59:59.000Z

453

Water Velocity Measurement on an Extended-Length Submerged Bar Screen at John Day Dam  

DOE Green Energy (OSTI)

This report describes a study of water velocity around an extended-length submerged bar screen (ESBS) at John Day Dam. The study was conducted for the U.S. Army Corps of Engineers by AScI Corporation and MEVATEC Corporation in March of 2000. This report was prepared by Pacific Northwest National Laboratory. ESBS are being studied as one method for diverting juvenile migrating fish from the dam's turbine intakes into the gate well and through the juvenile fish bypass channels.

Weiland, Mark A

2001-04-02T23:59:59.000Z

454

A 4906 CHANNEL TWO-DIMENSIONAL ANALYZER FOR THE MTR VELOCITY SELECTOR  

SciTech Connect

The analyzer forms part of the Materials Testing Reactor Velocity Selector Experiment which measures energy change versus scattering angle for subthermal neutrons scattered off a target. It is similar to other time-of- flight lyzers except for certain unique features. Among these features are input and output buffer matrices, a randomly pulsed crystal time-base generator, and a direct 48transistor drive circuit for the 4096 channel magnetic core matrix. (auth)

Petree, F.L.

1961-12-22T23:59:59.000Z

455

The effect of arc velocity on cold electrode erosion Alexei M. Essiptchouk,a)  

E-Print Network (OSTI)

of the radial redistribution of the gas due to centrifugal force in the vortex. Therefore the cold- est gas in air, for magnetic induction values B in the range of 0.005­0.386 T, axial air gas velocity of 7.65 ms displacement are used to diminish the erosion of the electrode: gas dynamic, i.e., application of vortex flow

Marotta, Aruy

456

Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory  

E-Print Network (OSTI)

I present an empirical model for predicting a star's radial velocity jitter from its B-V color, activity level, and absolute magnitude. This model is based on observations of 450 well- observed stars from Keck Observatory for the California and Carnegie Planet Search Program. The model includes noise from both astrophysical sources and systematic errors, and describes jitter as generally increasing with a star's activity and height above the main sequence.

J. T. Wright

2005-05-11T23:59:59.000Z

457

Symmetry properties of the large-deviation function of the velocity of a self-propelled polar particle  

E-Print Network (OSTI)

A geometrically polar granular rod confined in 2-D geometry, subjected to a sinusoidal vertical oscillation, undergoes noisy self-propulsion in a direction determined by its polarity. When surrounded by a medium of crystalline spherical beads, it displays substantial negative fluctuations in its velocity. We find that the large deviation function (LDF) for the normalized velocity is strongly non-Gaussian with a kink at zero velocity, and that the antisymmetric part of the LDF is linear, resembling the fluctuation relation known for entropy production, even when the velocity distribution is clearly non-Gaussian. We extract an analogue of the phase space contraction rate and find that it compares well with an independent estimate based on the persistence of forward and reverse velocities.

Nitin Kumar; Sriram Ramaswamy; A. K. Sood

2010-09-29T23:59:59.000Z

458

Description of sprays using joint hyperbolic distribution in particle size and velocity  

SciTech Connect

The joint probability density functions of droplet size and velocity have been represented in sprays by the two-dimensional hyperbolic distribution. A distribution is provided, and a procedure to compute its eight parameters outlined. Analytical expressions for certain statistical quantities, such as mean diameters, momentum, kinetic energy etc., applicable under certain restrictions, are obtained. The computations for a water spray issuing from a Danfoss 60{degrees} solid cone oil-burner nozzle demonstrate not only that the hyperbolic distribution provides an excellent approximation for the joint size and velocity distributions for the measurements taken along the entire length of the spray axis, but also that such representation presents a clear insight into the physics of the motion and the related size formation. The computations reveal a developing region, with areas dominated by breakup or coalescence of droplets, followed by a developed state with little change in droplet size but continuously decreasing velocity. It is concluded that this novel approach is well suited to the description of sprays.

Bhatia, J.C.; Durst, F. (LSTM-Erlangen, Lehrstuhl fur Stromungsmechanik, Universitat Erlangen-Nurnberg, 8520 Erlangen (DE))

1990-09-01T23:59:59.000Z

459

AN AFFINE-INVARIANT SAMPLER FOR EXOPLANET FITTING AND DISCOVERY IN RADIAL VELOCITY DATA  

SciTech Connect

Markov chain Monte Carlo (MCMC) proves to be powerful for Bayesian inference and in particular for exoplanet radial velocity fitting because MCMC provides more statistical information and makes better use of data than common approaches like chi-square fitting. However, the nonlinear density functions encountered in these problems can make MCMC time-consuming. In this paper, we apply an ensemble sampler respecting affine invariance to orbital parameter extraction from radial velocity data. This new sampler has only one free parameter, and does not require much tuning for good performance, which is important for automatization. The autocorrelation time of this sampler is approximately the same for all parameters and far smaller than Metropolis-Hastings, which means it requires many fewer function calls to produce the same number of independent samples. The affine-invariant sampler speeds up MCMC by hundreds of times compared with Metropolis-Hastings in the same computing situation. This novel sampler would be ideal for projects involving large data sets such as statistical investigations of planet distribution. The biggest obstacle to ensemble samplers is the existence of multiple local optima; we present a clustering technique to deal with local optima by clustering based on the likelihood of the walkers in the ensemble. We demonstrate the effectiveness of the sampler on real radial velocity data.

Hou Fengji; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Goodman, Jonathan; Weare, Jonathan [Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 (United States); Schwab, Christian, E-mail: fh417@nyu.edu [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States)

2012-02-01T23:59:59.000Z

460

Positive/negative ion velocity mapping apparatus for electron-molecule reactions  

Science Conference Proceedings (OSTI)

In molecular dissociative ionization by electron collisions and dissociative electron attachment to molecule, the respective positively and negatively charged fragments are the important products. A compact ion velocity mapping apparatus is developed for the angular distribution measurements of the positive or negative fragments produced in the electron-molecule reactions. This apparatus consists of a pulsed electron gun, a set of ion velocity mapping optic lenses, a two-dimensional position detector including two pieces of micro-channel plates, and a phosphor screen, and a charge-coupled-device camera for data acquisition. The positive and negative ion detections can be simply realized by changing the voltage polarity of ion optics and detector. Velocity sliced images can be directly recorded using a narrow voltage pulse applied on the rear micro-channel plate. The efficient performance of this system is evaluated by measuring the angular distribution of O{sup -} from the electron attachments to NO at 7.3 and 8.3 eV and O{sup +} from the electron collision with CO at 40.0 eV.

Wu Bin; Xia Lei; Li Hongkai; Zeng Xianjin; Tian Shanxi [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2012-01-15T23:59:59.000Z