Sample records for high velocity sdhv

  1. High-velocity clouds: a diverse phenomenon

    E-Print Network [OSTI]

    B. P. Wakker

    2001-09-13T23:59:59.000Z

    In this contribution the current state of knowledge about the high-velocity clouds (HVCs) is summarized. Recent progress has shown that the HVCs are a diverse phenomenon. The intermediate-velocity clouds (IVCs) are likely to be part of a Galactic Fountain. The Magellanic Stream is a tidal remnant. HVC complex C (possibly complexes A and GCN) are low-metallicity clouds near the Galaxy; they could be remnants of the formation of the Galaxy or old tidal streams extracted from nearby dwarf galaxies. Having a substantial number of HI HVCs dispersed throughout the Local Group seems incompatible with the observed HI mass function of galaxies. Finally, FUSE finds high-velocity OVI, some of which is clearly associated with HI HVCs, but some which is not.

  2. Compact, Isolated High-Velocity Clouds

    E-Print Network [OSTI]

    W. B. Burton; R. Braun; V. de Heij

    2002-06-20T23:59:59.000Z

    We consider here the class of compact, isolated, high-velocity HI clouds, CHVCs, which are sharply bounded in angular extent down to a limiting column density of 1.5x10^18 cm^-2. We describe our automated search algorithm and it's application to the LDS north of dec= -28 deg. and the HIPASS data south of dec=0, resulting in an all--sky catalog numbering 246 CHVCs. We argue that these objects are more likely to represent a single phenomenon in a similar evolutionary state than would a sample which included any of the major HVC complexes. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densities, (4) the number distribution of angular sizes, and (5) the number distribution of line widths. We show that the spatial and kinematic deployments of the ensemble of CHVCs contain various clues regarding their characteristic distance. These clues are not compatible with a location of the ensemble within the Galaxy proper. The deployments resemble in several regards those of the Local Group galaxies. We describe a model testing the hypothesis that the CHVCs are a Local Group population. The agreement of the model with the data is judged by extracting the observables from simulations, in a manner consistent with the sensitivities of the observations and explicitly taking account of Galactic obscuration. We show that models in which the CHVCs are the HI counterparts of dark-matter halos evolving in the Local Group potential provide a good match to the observables, if account is taken of tidal and ram--pressure disruption, the consequences of obscuration due to Galactic HI and of differing sensitivities and selection effects pertaining to the surveys.

  3. Cryogenic Testing of High-Velocity Spoke Cavities

    SciTech Connect (OSTI)

    Hopper, Christopher S. [Old Dominion University; Delayen, Jean R. [Old Dominion University; Park, HyeKyoung [JLAB

    2014-12-01T23:59:59.000Z

    Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, ?0= 0.82 single-spoke cavity and a 500 MHz, ?0 = 1 double-spoke cavity.

  4. High-resolution imaging of compact high-velocity clouds

    E-Print Network [OSTI]

    Robert Braun; Butler Burton

    1999-12-20T23:59:59.000Z

    Six examples of the compact, isolated high-velocity HI clouds (CHVCs) identified by Braun and Burton (1999) have been imaged with the WSRT. The 65 confirmed objects in this class define a dynamically cold system, with a global minimum for the velocity dispersion of only 70 km/s, found in the Local Group Standard of Rest, while in-falling at 100 km/s toward the LG barycenter. These objects have a characteristic morphology, in which several compact cores are embedded in a diffuse halo. The compact cores typically account for 40% of the HI line flux while covering some 15% of the source area. The cores are the cool condensed phase of HI, the CNM, with temp. near 100 K, while the halos appear to be a shielding column of warm diffuse HI, the WNM, with temp. near 8000 K. We detect a core with one of the narrowest HI emission lines ever observed, with intrinsic FWHM of 2 km/s and 75 K brightness. From a comparison of column and volume densities we derive a distance in the range 0.5 to 1 Mpc. We determine a metallicity for this same object of 0.04 to 0.07 solar. Comparably high distances are implied by demanding the stability of objects with multiple cores, which show relative velocities as large as 70 km/s on 30 arcmin scales. Many compact cores show systematic velocity gradients along the major axis of their elliptical extent which are consistent with circular rotation. Several of the derived rotation curves are well-fit by Navarro, Frenk, and White (1997) cold dark matter profiles. These kinematic signatures imply a high dark-to-visible mass ratio of 10-50, for D=0.7Mpc, which scales as 1/D. The implied dark matter halos dominate the mass volume density within the central 2 kpc (10 arcmin) of each source, providing a sufficent hydrostatic pressure to allow local CNM condensation. (abridged)

  5. Compact High-Velocity Clouds at High Resolution

    E-Print Network [OSTI]

    W. B. Burton; Robert Braun

    1999-12-22T23:59:59.000Z

    Six examples of the compact, isolated high-velocity clouds catalogued by Braun & Burton (1999) and identified with a dynamically cold ensemble of primitive objects falling towards the barycenter of the Local Group have been imaged with the Westerbork Synthesis Radio Telescope; an additional ten have been imaged with the Arecibo telescope. The imaging reveals a characteristic core/halo morphology: one or several cores of cool, relatively high-column-density material, are embedded in an extended halo of warmer, lower-density material. Several of the cores show kinematic gradients consistent with rotation; these CHVCs are evidently rotationally supported and dark-matter dominated. The imaging data allows several independent estimates of the distances to these objects, which lie in the range 0.3 to 1.0 Mpc. The CHVC properties resemble what might be expected from very dark dwarf irregular galaxies.

  6. Superconducting spoke cavities for high-velocity applications

    SciTech Connect (OSTI)

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

    2013-10-01T23:59:59.000Z

    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.

  7. Modeling and Control of High-Velocity Oxygen-Fuel (HVOF) Thermal Spray: A Tutorial Review

    E-Print Network [OSTI]

    Li, Mingheng; Christofides, Panagiotis D.

    2009-01-01T23:59:59.000Z

    Fluid Dynamics Analysis of a Wire- Feed, High-Velocity Oxygen Fuel (Fluid Dynamic Modeling of Gas Flow Charac- teristics in a High-Velocity Oxy-Fuel

  8. High velocity compact clouds in the sagittarius C region

    SciTech Connect (OSTI)

    Tanaka, Kunihiko; Oka, Tomoharu; Matsumura, Shinji [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, Kanagawa 223-8522 (Japan); Nagai, Makoto [Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Ten-noudai, Tsukuba, Ibaraki 305-8571 (Japan); Kamegai, Kazuhisa, E-mail: ktanaka@phys.keio.ac.jp [Department of Industrial Administration, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan)

    2014-03-01T23:59:59.000Z

    We report the detection of extremely broad emission toward two molecular clumps in the Galactic central molecular zone. We have mapped the Sagittarius C complex (–0.°61 < l < –0.°27, –0.°29 < b < 0.°04) in the HCN J = 4-3, {sup 13}CO J = 3-2, and H{sup 13}CN J = 1-0 lines with the ASTE 10 m and NRO 45 m telescopes, detecting bright emission with 80-120 km s{sup –1} velocity width (in full-width at zero intensity) toward CO–0.30–0.07 and CO–0.40–0.22, which are high velocity compact clouds (HVCCs) identified with our previous CO J = 3-2 survey. Our data reveal an interesting internal structure of CO–0.30–0.07 comprising a pair of high velocity lobes. The spatial-velocity structure of CO–0.40–0.22 can be also understood as a multiple velocity component, or a velocity gradient across the cloud. They are both located on the rims of two molecular shells of about 10 pc in radius. Kinetic energies of CO–0.30–0.07 and CO–0.40–0.22 are (0.8-2) × 10{sup 49} erg and (1-4) × 10{sup 49} erg, respectively. We propose several interpretations of their broad emission: collision between clouds associated with the shells, bipolar outflow, expansion driven by supernovae (SNe), and rotation around a dark massive object. These scenarios cannot be discriminated because of the insufficient angular resolution of our data, though the absence of a visible energy source associated with the HVCCs seems to favor the cloud-cloud collision scenario. Kinetic energies of the two molecular shells are 1 × 10{sup 51} erg and 0.7 × 10{sup 51} erg, which can be furnished by multiple SN or hypernova explosions in 2 × 10{sup 5} yr. These shells are candidates of molecular superbubbles created after past active star formation.

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

    E-Print Network [OSTI]

    Jian-Miin Liu

    2001-08-18T23:59:59.000Z

    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.

  10. Arecibo imaging of compact high-velocity clouds

    E-Print Network [OSTI]

    Burton, W B; Chengalur, J N

    2001-01-01T23:59:59.000Z

    Ten isolated compact high-velocity clouds (CHVCs) of the type cataloged by Braun & Burton (1999) have been imaged with the Arecibo telescope and were found to have a nested core/halo morphology. We argue that a combination of high-resolution filled-aperture and synthesis data is crucial to determining the intrinsic properties of the CHVCs. We identify the halos as Warm Neutral Medium surrounding one or more cores in the Cool Neutral Medium phase. These halos are clearly detected and resolved by the Arecibo filled-aperture imaging, which reaches a limiting sensitivity (1 sigma) of N_H about 2x10^17 cm^-2 over the typical 70 km/s linewidth at zero intensity. The FWHM linewidth of the halo gas is found to be 25 km/s, consistent with a WNM thermal broadening within 10^4 K gas. Substantial asymmetries are found at high N_H (>10^18.5 cm^-2) levels in 60% of our sample. A high degree of reflection-symmetry is found at low N_H (<10^18.5 cm^-2) in all sources studied at these levels. The column-density profiles...

  11. Introduction The Smith Cloud is a high velocity cloud with a radial velocity near

    E-Print Network [OSTI]

    Wisconsin at Madison, University of

    .8 ­ 15.1 kpc (Wakker et al. 2008). Lockman et al. (2008) presented an H I survey of the cloud using the off and on spectra of each line to a single atmospheric template, which we then subtracted from velocities, Figure 2 shows ON­OFF spectra with no atmospheric template for this line. Like Bland-Hawthorn et

  12. Arecibo imaging of compact high-velocity clouds

    E-Print Network [OSTI]

    W. B. Burton; R. Braun; J. N. Chengalur

    2001-02-06T23:59:59.000Z

    Ten isolated compact high-velocity clouds (CHVCs) of the type cataloged by Braun & Burton (1999) have been imaged with the Arecibo telescope and were found to have a nested core/halo morphology. We argue that a combination of high-resolution filled-aperture and synthesis data is crucial to determining the intrinsic properties of the CHVCs. We identify the halos as Warm Neutral Medium surrounding one or more cores in the Cool Neutral Medium phase. These halos are clearly detected and resolved by the Arecibo filled-aperture imaging, which reaches a limiting sensitivity (1 sigma) of N_H about 2x10^17 cm^-2 over the typical 70 km/s linewidth at zero intensity. The FWHM linewidth of the halo gas is found to be 25 km/s, consistent with a WNM thermal broadening within 10^4 K gas. Substantial asymmetries are found at high N_H (>10^18.5 cm^-2) levels in 60% of our sample. A high degree of reflection-symmetry is found at low N_H (<10^18.5 cm^-2) in all sources studied at these levels. The column-density profiles of the envelopes are described well by the sky-plane projection of a spherical exponential in atomic volume density, which allows estimating the characteristic central halo column density, N_H(0) = 4.1+/-3.2x10^19 cm^-2, and characteristic exponential scale-length, h_B=420+/-90 arcsec. For plausible values of the thermal pressure at the CNM/WNM interface, these edge profiles allow distance estimates to be made for the individual CHVCs studied here which range between 150 and 850 kpc. (abridged)

  13. Distances and Metallicities of High- and Intermediate-Velocity Clouds

    E-Print Network [OSTI]

    B. P. Wakker

    2001-02-08T23:59:59.000Z

    A table is presented that summarizes published absorption line measurements for the high- and intermediate velocity clouds (HVCs and IVCs). New values are derived for N(HI) in the direction of observed probes, in order to arrive at reliable abundances and abundance limits (the HI data are described in Paper II). Distances to stellar probes are revisited and calculated consistently, in order to derive distance brackets or limits for many of the clouds, taking care to properly interpret non-detections. The main conclusions are the following. 1) Absolute abundances have been measured using lines of SII, NI and OI, with the following resulting values: ~0.1 solar for one HVC (complex C), ~0.3 solar for the Magellanic Stream, ~0.5 solar for a southern IVC, and ~ solar for two northern IVCs (the IV Arch and LLIV Arch). Finally, approximate values in the range 0.5-2 solar are found for three more IVCs. 2) Depletion patterns in IVCs are like those in warm disk or halo gas. 3) Most distance limits are based on strong UV lines of CII, SiII and MgII, a few on CaII. Distance limits for major HVCs are >5 kpc, while distance brackets for several IVCs are in the range 0.5-2 kpc. 4) Mass limits for major IVCs are 0.5-8x10^5 M_sun, but for major HVCs they are >10^6 M_sun. 5) The CaII/HI ratio varies by up to a factor 2-5 within a single cloud, somewhat more between clouds. 6) The NaIHI ratio varies by a factor >10 within a cloud, and even more between clouds. Thus, CaII can be useful for determining both lower and upper distance limits, but NaI only yields upper limits.

  14. High- and low-temperature-stable thermite composition for producing high-pressure, high-velocity gases

    DOE Patents [OSTI]

    Halcomb, Danny L. (Camden, OH); Mohler, Jonathan H. (Spring Valley, OH)

    1990-10-16T23:59:59.000Z

    A high- and low-temperature-stable thermite composition for producing high-pressure and high-velocity gases comprises an oxidizable metal, an oxidizing reagent, and a high-temperature-stable gas-producing additive selected from the group consisting of metal carbides and metal nitrides.

  15. HIGH-VELOCITY CLOUDS IN THE NEARBY SPIRAL GALAXY M 83

    E-Print Network [OSTI]

    Miller, Eric D.

    We present deep H I 21 cm and optical observations of the face-on spiral galaxy M 83 obtained as part of a project to search for high-velocity clouds (HVCs) in nearby galaxies. Anomalous-velocity neutral gas is detected ...

  16. Hohlraum Designs for High Velocity Implosions on NIF

    SciTech Connect (OSTI)

    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

    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%.

  17. Doppler-Shift Asymmetry in High-Velocity Maser Emission from Shocks in Circumnuclear Disks

    E-Print Network [OSTI]

    Eyal Maoz; Christopher F. McKee

    1997-04-04T23:59:59.000Z

    SHORT VERSION: The rapidly rotating, masing circumnuclear disk in the central sub-parsec region of the galaxy NGC 4258 is remarkably circular and Keplerian, yet a striking asymmetry appears in the maser spectrum: the red-shifted, high- velocity sources are much more numerous and significantly more intense than the blue-shifted ones. A similar strong asymmetry appears also in the recently discovered, masing, circumnuclear disks in NGC 1068 and NGC 4945, thus suggesting it may be a general phenomenon. We show that the observed Doppler-shift asymmetry can naturally arise due to spiral shocks in circumnuclear disks, independent of the existence of a warp in the disk or the azimuthal direction to the observer. The high velocities of these features reflect the rotational velocities in the disk, and have nothing to do with the shock speed. In NGC 4258 - the currently most well-defined masing disk - the proposed scenario can also account for the intriguing clustering of the high-velocity maser spots in distinct clumps, the restricted spatial distribution of the low-velocity sources, and the dip in the maser spectrum at the systemic velocity of the disk. In this case we infer a disk mass of ~10E4 M_sun and a mass accretion rate of order ~7E-3 M_sun/year, which may be consistent with an advection-dominated accretion flow. The model is consistent with the observed Keplerian rotation, and introduces only negligible corrections to the previously derived black hole mass and galaxy distance. Predictions include slow systematic drifts in the velocity and position of all the high-velocity features, and the existence of circumnuclear disks which are delineated only by high-velocity maser emission.

  18. Morphological Characteristics of Compact High-Velocity Clouds Revealed by High-Resolution WSRT Imaging

    E-Print Network [OSTI]

    W. B. Burton; Robert Braun

    1999-12-22T23:59:59.000Z

    A class of compact, isolated high-velocity clouds which plausibly represents a homogeneous subsample of the HVC phenomenon in a single physical state was objectively identified by Braun and Burton (1999). Six examples of the CHVCs, unresolved in single-dish data, have been imaged with the Westerbork Synthesis Radio Telescope. The high-resolution imaging reveals the morphology of these objects, including a core/halo distribution of fluxes, signatures of rotation indicating dark matter, and narrow linewidths constraining the kinetic temperature of several opaque cores. In these regards, as well as in their kinematic and spatial deployment on the sky, the CHVC objects are evidently a dynamically cold ensemble of dark-matter-dominated HI clouds accreting onto the Local Group in a continuing process of galactic evolution.

  19. Burning Velocities in Catalytically Assisted Self-Propagating High-Temperature Combustion Synthesis Systems

    E-Print Network [OSTI]

    Wooldridge, Margaret S.

    Burning Velocities in Catalytically Assisted Self-Propagating High-Temperature Combustion Synthesis of catalytically assisted self-propagating high-temperature synthesis (SHS) of the tantalum/carbon material system. © 2001 by The Combustion Institute INTRODUCTION Self-propagating high-temperature combustion synthesis

  20. High-resolution imaging of compact high-velocity clouds (II)

    E-Print Network [OSTI]

    V. de Heij; R. Braun; W. B. Burton

    2002-06-19T23:59:59.000Z

    We have imaged five compact high-velocity clouds in HI with arcmin angular- and km/s spectral-resolution using the WSRT. Supplementary total-power data, which is fully sensitive to both the cool and warm components of HI, is available for comparison for all the sources, albeit with angular resolutions that vary from 3' to 36'. The fractional HI flux in compact CNM components varies from 4% to 16% in our sample. All objects have at least one local peak in the CNM column which exceeds about 10^19 cm^-2 when observed with arcmin resolution. It is plausible that a peak column density of 1-2x10^19 cm^-2 is a prerequisite for the long-term survival of these sources. One object in our sample, CHVC120-20-443 (Davies' cloud), lies in close projected proximity to the disk of M31. This object is characterized by exceptionally broad linewidths in its CNM concentrations (more than 5 times greater than the median value). These CNM concentrations lie in an arc on the edge of the source facing the M31 disk, while the diffuse HI component of this source has a position offset in the direction of the disk. All of these attributes suggest that CHVC120-20-443 is in a different evolutionary state than most of the other CHVCs which have been studied. Similarly broad CNM linewidths have only been detected in one other object, CHVC111-07-466, which also lies in the Local Group barycenter direction and has the most extreme radial velocity known. A distinct possibility for Davies' cloud seems to be physical interaction of some type with M31. The most likely form of this interaction might be the ram-pressure or tidal- stripping by either one of M31's visible dwarf companions, M32 or NGC205, or else by a dark companion with an associated HI condensation.

  1. HIGH-VELOCITY CLOUDS IN THE GALACTIC ALL SKY SURVEY. I. CATALOG

    SciTech Connect (OSTI)

    Moss, V. A.; Kummerfeld, J. K. [Sydney Institute for Astronomy, School of Physics A29, University of Sydney, Sydney, NSW 2006 (Australia); McClure-Griffiths, N. M.; Murphy, T. [CSIRO Astronomy and Space Science, ATNF, P.O. Box 76, Epping, NSW 1710 (Australia); Pisano, D. J. [Department of Physics, West Virginia University, P.O. Box 6315, Morgantown, WV 26506 (United States); Curran, J. R., E-mail: vmoss@physics.usyd.edu.au [School of Information Technologies, University of Sydney, Sydney, NSW 2006 (Australia)

    2013-11-01T23:59:59.000Z

    We present a catalog of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern sky neutral hydrogen, which has 57 mK sensitivity and 1 km s{sup –1} velocity resolution and was obtained with the Parkes Telescope. Our catalog has been derived from the stray-radiation-corrected second release of GASS. We describe the data and our method of identifying HVCs and analyze the overall properties of the GASS population. We catalog a total of 1693 HVCs at declinations <0°, including 1111 positive velocity HVCs and 582 negative velocity HVCs. Our catalog also includes 295 anomalous velocity clouds (AVCs). The cloud line-widths of our HVC population have a median FWHM of ?19 km s{sup –1}, which is lower than that found in previous surveys. The completeness of our catalog is above 95% based on comparison with the HIPASS catalog of HVCs upon which we improve by an order of magnitude in spectral resolution. We find 758 new HVCs and AVCs with no HIPASS counterpart. The GASS catalog will shed unprecedented light on the distribution and kinematic structure of southern sky HVCs, as well as delve further into the cloud populations that make up the anomalous velocity gas of the Milky Way.

  2. High-resolution velocity field imaging around a borehole: Excavation Damaged Zone characterization

    E-Print Network [OSTI]

    Boyer, Edmond

    .balland@ineris.fr, vincent.renaud@ineris.fr ABSTRACT The excavation of a deep underground structure induces a stress field of a material. In the case of underground storage, rock damage will affect the rock capacity to confine1 High-resolution velocity field imaging around a borehole: Excavation Damaged Zone

  3. Method and apparatus for optical Doppler tomographic imaging of fluid flow velocity in highly scattering media

    DOE Patents [OSTI]

    Nelson, John Stuart (Laguna Niguel, CA); Milner, Thomas Edward (Irvine, CA); Chen, Zhongping (Irvine, CA)

    1999-01-01T23:59:59.000Z

    Optical Doppler tomography permits imaging of fluid flow velocity in highly scattering media. The tomography system combines Doppler velocimetry with high spatial resolution of partially coherent optical interferometry to measure fluid flow velocity at discrete spatial locations. Noninvasive in vivo imaging of blood flow dynamics and tissue structures with high spatial resolutions of the order of 2 to 10 microns is achieved in biological systems. The backscattered interference signals derived from the interferometer may be analyzed either through power spectrum determination to obtain the position and velocity of each particle in the fluid flow sample at each pixel, or the interference spectral density may be analyzed at each frequency in the spectrum to obtain the positions and velocities of the particles in a cross-section to which the interference spectral density corresponds. The realized resolutions of optical Doppler tomography allows noninvasive in vivo imaging of both blood microcirculation and tissue structure surrounding the vessel which has significance for biomedical research and clinical applications.

  4. A confirmed location in the Galactic halo for the high-velocity cloud 'chain A'

    E-Print Network [OSTI]

    Hugo van Woerden; Ulrich J. Schwarz; Reynier F. Peletier; Bart P. Wakker; Peter M. W. Kalberla

    1999-07-08T23:59:59.000Z

    The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^6 solar masses.

  5. A confirmed location in the Galactic halo for the high-velocity cloud "chain A"

    E-Print Network [OSTI]

    Van Woerden, H; Peletier, R F; Wakker, B P; Kalberla, P M W; Woerden, Hugo van; Schwarz, Ulrich J.; Peletier, Reynier F.; Wakker, Bart P.; Kalberla, Peter M.W.

    1999-01-01T23:59:59.000Z

    The high-velocity clouds of atomic hydrogen, discovered about 35 years ago, have velocities inconsistent with simple Galactic rotation models that generally fit the stars and gas in the Milky Way disk. Their origins and role in Galactic evolution remain poorly understood, largely for lack of information on their distances. The high-velocity clouds might result from gas blown from the Milky Way disk into the halo by supernovae, in which case they would enrich the Galaxy with heavy elements as they fall back onto the disk. Alternatively, they may consist of metal-poor gas -- remnants of the era of galaxy formation, accreted by the Galaxy and reducing its metal abundance. Or they might be truly extragalactic objects in the Local Group of galaxies. Here we report a firm distance bracket for a large high-velocity cloud, Chain A, which places it in the Milky Way halo (2.5 to 7 kiloparsecs above the Galactic plane), rather than at an extragalactic distance, and constrains its gas mass to between 10^5 and 2 times 10^...

  6. High-Velocity Features of Calcium and Silicon in the Spectra of Type Ia Supernovae

    E-Print Network [OSTI]

    Silverman, Jeffrey M; Marion, G H; Wheeler, J Craig; Barna, Barnabas; Szalai, Tamas; Mulligan, Brian; Filippenko, Alexei V

    2015-01-01T23:59:59.000Z

    "High-velocity features" (HVFs) are spectral features in Type Ia supernovae (SNe Ia) that have minima indicating significantly higher (by greater than about 6000 km/s) velocities than typical "photospheric-velocity features" (PVFs). The PVFs are absorption features with minima indicating typical photospheric (i.e., bulk ejecta) velocities (usually ~9000-15,000 km/s near B-band maximum brightness). In this work we undertake the most in-depth study of HVFs ever performed. The dataset used herein consists of 445 low-resolution optical and near-infrared (NIR) spectra (at epochs up to 5 d past maximum brightness) of 210 low-redshift SNe Ia that follow the "Phillips relation." A series of Gaussian functions is fit to the data in order to characterise possible HVFs of Ca II H&K, Si II {\\lambda}6355, and the Ca II NIR triplet. The temporal evolution of the velocities and strengths of the PVFs and HVFs of these three spectral features is investigated, as are possible correlations with other SN Ia observables. We f...

  7. Laser Doppler field sensor for high resolution flow velocity imaging without camera

    SciTech Connect (OSTI)

    Voigt, Andreas; Bayer, Christian; Shirai, Katsuaki; Buettner, Lars; Czarske, Juergen

    2008-09-20T23:59:59.000Z

    In this paper we present a laser sensor for highly spatially resolved flow imaging without using a camera. The sensor is an extension of the principle of laser Doppler anemometry (LDA). Instead of a parallel fringe system, diverging and converging fringes are employed. This method facilitates the determination of the tracer particle position within the measurement volume and leads to an increased spatial and velocity resolution compared to conventional LDA. Using a total number of four fringe systems the flow is resolved in two spatial dimensions and the orthogonal velocity component. Since no camera is used, the resolution of the sensor is not influenced by pixel size effects. A spatial resolution of 4 {mu}m in the x direction and 16 {mu}m in the y direction and a relative velocity resolution of 1x10{sup -3} have been demonstrated up to now. As a first application we present the velocity measurement of an injection nozzle flow. The sensor is also highly suitable for applications in nano- and microfluidics, e.g., for the measurement of flow rates.

  8. SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU

    SciTech Connect (OSTI)

    Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Cenko, S. B.; Filippenko, A. V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Silverman, J. M. [Department of Astronomy, University of Texas, Austin, TX 78712-0259 (United States); Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Jha, S. W.; McCully, C. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Anderson, J. P.; De Jaeger, T.; Forster, F. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Benetti, S. [INAF Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy); Bufano, F., E-mail: mjc@mso.anu.edu.au [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avda. Republica 252, Santiago (Chile); and others

    2013-06-10T23:59:59.000Z

    We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II {lambda}6355 line that can be cleanly decoupled from the lower velocity ''photospheric'' component. This Si II {lambda}6355 HVF fades by phase -5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of {approx}12,000 km s{sup -1} until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v Almost-Equal-To 12,000 km s{sup -1} with narrow line width and long velocity plateau, as well as an HVF beginning at v Almost-Equal-To 31,000 km s{sup -1} two weeks before maximum. SN 2012fr resides on the border between the ''shallow silicon'' and ''core-normal'' subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the ''low velocity gradient'' group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

  9. Higher velocity, high-foot implosions on the National Ignition Facility laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Callahan, D. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000315498916); Hurricane, O. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hinkel, D. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Döppner, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ma, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Park, H. -S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barrios Garcia, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Berzak Hopkins, L. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000291875667); Casey, D. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cerjan, C. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000251686845); Dewald, E. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dittrich, T. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Edwards, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haan, S. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000184045131); Hamza, A. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kline, J. L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Knauer, J. P. [Univ. of Rochester, NY (United States); Kritcher, A. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Landen, O. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); LePape, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); MacPhee, A. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000341604479); Milovich, J. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nikroo, A. [General Atomics, San Diego, CA (United States)] (ORCID:0000000288550378); Pak, A. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Patel, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rygg, J. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ralph, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Salmonson, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Spears, B. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Springer, P. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tommasini, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benedetti, L. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bionta, R. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bond, E. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bradley, D. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Caggiano, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Field, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fittinghoff, D. N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Frenje, J. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States)] (ORCID:0000000168460378); Gatu Johnson, M. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Grim, G. P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hatarik, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Merrill, F. E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nagel, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)] (ORCID:0000000277686819); Izumi, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Khan, S. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-01T23:59:59.000Z

    By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), and the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1e15 neutrons, the total yield ~ v???. This increase is considerably faster than the expected dependence for implosions without alpha heating ( ~v???) and is additional evidence that these experiments have significant alpha heating.

  10. Higher velocity, high-foot implosions on the National Ignition Facility laser

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Callahan, D. A.; Hurricane, O. A.; Hinkel, D. E.; Döppner, T.; Ma, T.; Park, H. -S.; Barrios Garcia, M. A.; Berzak Hopkins, L. F.; Casey, D. T.; Cerjan, C. J.; et al

    2015-05-01T23:59:59.000Z

    By increasing the velocity in “high foot” implosions [Dittrich et al., Phys. Rev. Lett. 112, 055002 (2014); Park et al., Phys. Rev. Lett. 112, 055001 (2014); Hurricane et al., Nature 506, 343 (2014); Hurricane et al., Phys. Plasmas 21, 056314 (2014)] on the National Ignition Facility laser, we have nearly doubled the neutron yield and the hotspot pressure as compared to the implosions reported upon last year. The implosion velocity has been increased using a combination of the laser (higher power and energy), the hohlraum (depleted uranium wall material with higher opacity and lower specific heat than gold hohlraums), andmore »the capsule (thinner capsules with less mass). We find that the neutron yield from these experiments scales systematically with a velocity-like parameter of the square root of the laser energy divided by the ablator mass. By connecting this parameter with the inferred implosion velocity (v), we find that for shots with primary yield >1e15 neutrons, the total yield ~ v???. This increase is considerably faster than the expected dependence for implosions without alpha heating ( ~v???) and is additional evidence that these experiments have significant alpha heating.« less

  11. Westerbork HI observations of high-velocity clouds near M31 and M33

    E-Print Network [OSTI]

    T. Westmeier; R. Braun; D. Thilker

    2005-03-10T23:59:59.000Z

    We have undertaken high-resolution follow-up of a sample of high velocity HI clouds apparently associated with M31. Our sample was chosen from the population of high-velocity clouds (HVCs) detected out to 50 kpc projected radius of the Andromeda Galaxy by Thilker et al. (2004) with the Green Bank Telescope. Nine pointings were observed with the Westerbork Synthesis Radio Telescope to determine the physical parameters of these objects and to find clues to their origin. One additional pointing was directed at a similar object near M33. At 2' resolution we detect 16 individual HVCs around M31 and 1 HVC near M33 with typical HI masses of a few times 10^5 solar masses and sizes of the order of 1 kpc. Estimates of the dynamical and virial masses of some of the HVCs indicate that they are likely gravitationally dominated by additional mass components such as dark matter or ionised gas. Twelve of the clouds are concentrated in an area of only 1 by 1 degree at a projected separation of less than 15 kpc from the disk of M31. This HVC complex has a rather complicated morphological and kinematical structure and partly overlaps with the giant stellar stream of M31, suggesting a tidal origin. Another detected feature is in close proximity, in both position and velocity, with NGC 205, perhaps also indicative of tidal processes. Other HVCs in our survey are isolated and might represent primordial, dark-matter dominated clouds.

  12. The Kinematic and Spatial Deployment of Compact, Isolated High-Velocity Clouds

    E-Print Network [OSTI]

    R. Braun; W. B. Burton

    1998-10-27T23:59:59.000Z

    We have identified a class of high-velocity clouds which are compact and apparently isolated. The clouds are compact in that they have angular sizes less than 2 degrees FWHM. They are isolated in that they are separated from neighboring emission by expanses where no emission is seen to the detection limit of the available data. Candidates for inclusion in this class were extracted from the Leiden/Dwingeloo HI survey of Hartmann & Burton and from the Wakker & van Woerden catalogue of high-velocity clouds. The candidates were subject to independent confirmation using either the 25-meter telescope in Dwingeloo or the 140-foot telescope in Green Bank. We argue that the resulting list, even if incomplete, is sufficiently representative of the ensemble of compact, isolated HVCs - CHVCs - that the characteristics of their disposition on the sky, and of their kinematics, are revealing of some physical aspects of the class. The CHVCs are in fact distributed quite uniformly across the sky. A global search for the reference frame which minimizes the velocity dispersion of the ensemble returns the Local Group Standard of Rest with high confidence. The CHVCs are not stationary with respect to this reference frame but have a mean infall velocity of 100 km/s. These properties are strongly suggestive of a population which has as yet had little interaction with the more massive Local Group members. At a typical distance of about 1 Mpc these objects would have sizes of about 15 kpc and gas masses, M_HI, of a few times 10^7 M_Sun, corresponding to those of (sub-)dwarf galaxies. (abridged)

  13. Mapping High-velocity H-alpha and Lyman-alpha Emission from Supernova 1987A

    E-Print Network [OSTI]

    France, Kevin; Fransson, Claes; Larsson, Josefin; Frank, Kari A; Burrows, David N; Challis, Peter; Kirshner, Robert P; Chevalier, Roger A; Garnavich, Peter; Heng, Kevin; Lawrence, Stephen S; Lundqvist, Peter; Smith, Nathan; Sonneborn, George

    2015-01-01T23:59:59.000Z

    We present new {\\it Hubble Space Telescope} images of high-velocity H-$\\alpha$ and Lyman-$\\alpha$ emission in the outer debris of SN~1987A. The H-$\\alpha$ images are dominated by emission from hydrogen atoms crossing the reverse shock. For the first time we observe emission from the reverse shock surface well above and below the equatorial ring, suggesting a bipolar or conical structure perpendicular to the ring plane. Using the H$\\alpha$ imaging, we measure the mass flux of hydrogen atoms crossing the reverse shock front, in the velocity intervals ($-$7,500~$<$~$V_{obs}$~$<$~$-$2,800 km s$^{-1}$) and (1,000~$<$~$V_{obs}$~$<$~7,500 km s$^{-1}$), $\\dot{M_{H}}$ = 1.2~$\\times$~10$^{-3}$ M$_{\\odot}$ yr$^{-1}$. We also present the first Lyman-$\\alpha$ imaging of the whole remnant and new $Chandra$ X-ray observations. Comparing the spatial distribution of the Lyman-$\\alpha$ and X-ray emission, we observe that the majority of the high-velocity Lyman-$\\alpha$ emission originates interior to the equatorial...

  14. PTF 12gzk—A rapidly declining, high-velocity type Ic radio supernova

    SciTech Connect (OSTI)

    Horesh, Assaf; Kulkarni, Shrinivas R. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Corsi, Alessandra [Department of Physics, The George Washington University, 725 21st Street, NW, Washington, DC 20052 (United States); Frail, Dale A. [National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801 (United States); Cenko, S. Bradley [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Ben-Ami, Sagi; Gal-Yam, Avishay; Yaron, Ofer; Arcavi, Iair; Ofek, Eran O. [Department of Particle Physics and Astrophysics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Kasliwal, Mansi M. [Carnegie Institution for Science, Department of Terrestrial Magnetism, 5241 Broad Branch Road, Washington, DC 20008 (United States)

    2013-11-20T23:59:59.000Z

    Only a few cases of Type Ic supernovae (SNe) with high-velocity ejecta (?0.2 c) have been discovered and studied. Here, we present our analysis of radio and X-ray observations of the Type Ic SN PTF 12gzk. The radio emission declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (?0.3 c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ?10 than the CSM around normal Type Ic SNe. PTF 12gzk may therefore be an intermediate event between a 'normal' SN Ic and a gamma-ray-burst-SN-like event. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the Very Large Array (improved sensitivity and dynamic scheduling), which are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions as well as strong clues about the nature of their progenitor stars.

  15. A Compact Circumstellar Shell as the Source of High--velocity Features in SN 2011fe

    E-Print Network [OSTI]

    Mulligan, Brian W

    2015-01-01T23:59:59.000Z

    High--velocity features (HVF), especially of Ca II, are frequently seen in Type Ia supernovae observed prior to B-band maximum (Bmax). These HVF start at more than 25,000 km/s in the days after first light, and slow to about 18,000 km/s near Bmax. To recreate the Ca II near-infrared triplet (CaNIR) HVF in SN 2011fe, we consider the interaction between a Type Ia supernova and a compact circumstellar shell, employing a hydrodynamic 1-D simulation using FLASH. We generate synthetic spectra from the hydrodynamic results using syn++. We show that the CaNIR HVF and its velocity evolution is better explained by a supernova model interacting with a shell than a model without a shell, and briefly discuss the implications for progenitor models.

  16. Revisit of the relationship between the elastic properties and sound velocities at high pressures

    SciTech Connect (OSTI)

    Wang, Chenju; Yan, Xiaozhen [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); Institute of Atomic and Molecular Sciences, Sichuan University, Chengdu 610065 (China); Xiang, Shikai, E-mail: skxiang@caep.ac.cn; Chen, Haiyan [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); Gu, Jianbing; Yu, Yin [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Kuang, Xiaoyu [Institute of Atomic and Molecular Sciences, Sichuan University, Chengdu 610065 (China); International Centre for Materials Physics, Academia Sinica, Shenyang 110016 (China)

    2014-09-14T23:59:59.000Z

    The second-order elastic constants and stress-strain coefficients are defined, respectively, as the second derivatives of the total energy and the first derivative of the stress with respect to strain. Since the Lagrangian and infinitesimal strain are commonly used in the two definitions above, the second-order elastic constants and stress-strain coefficients are separated into two categories, respectively. In general, any of the four physical quantities is employed to characterize the elastic properties of materials without differentiation. Nevertheless, differences may exist among them at non-zero pressures, especially high pressures. Having explored the confusing issue systemically in the present work, we find that the four quantities are indeed different from each other at high pressures and these differences depend on the initial stress applied on materials. Moreover, the various relations between the four quantities depicting elastic properties of materials and high-pressure sound velocities are also derived from the elastic wave equations. As examples, we calculated the high-pressure sound velocities of cubic tantalum and hexagonal rhenium using these nexus. The excellent agreement of our results with available experimental data suggests the general applicability of the relations.

  17. Aerosol formation from high-velocity uranium drops: Comparison of number and mass distributions. Final report

    SciTech Connect (OSTI)

    Rader, D.J.; Benson, D.A.

    1995-05-01T23:59:59.000Z

    This report presents the results of an experimental study of the aerosol produced by the combustion of high-velocity molten-uranium droplets produced by the simultaneous heating and electromagnetic launch of uranium wires. These tests are intended to simulate the reduction of high-velocity fragments into aerosol in high-explosive detonations or reactor accidents involving nuclear materials. As reported earlier, the resulting aerosol consists mainly of web-like chain agglomerates. A condensation nucleus counter was used to investigate the decay of the total particle concentration due to coagulation and losses. Number size distributions based on mobility equivalent diameter obtained soon after launch with a Differential Mobility Particle Sizer showed lognormal distributions with an initial count median diameter (CMD) of 0.3 {mu}m and a geometric standard deviation, {sigma}{sub g} of about 2; the CMD was found to increase and {sigma}{sub g} decrease with time due to coagulation. Mass size distributions based on aerodynamic diameter were obtained for the first time with a Microorifice Uniform Deposit Impactor, which showed lognormal distributions with mass median aerodynamic diameters of about 0.5 {mu}m and an aerodynamic geometric standard deviation of about 2. Approximate methods for converting between number and mass distributions and between mobility and aerodynamic equivalent diameters are presented.

  18. An automated search for high-velocity clouds in the Leiden/Dwingeloo Survey

    E-Print Network [OSTI]

    V. de Heij; R. Braun; W. B. Burton

    2002-01-15T23:59:59.000Z

    We describe an automated search through the Leiden/Dwingeloo HI Survey (LDS) for high-velocity clouds north of Dec=-28 deg. From the general catalog we extract a sample of isolated high-velocity clouds, CHVCs: anomalous-velocity HI clouds which are sharply bounded in angular extent with no kinematic or spatial connection to other HI features down to a limiting column density of 1.5*10^18cm^-2. This column density is an order of magnitude lower than the critical HI column density, about 2*10^19cm^-2, where the ionized fraction is thought to increase dramatically due to the extragalactic radiation field. As such, these objects are likely to provide their own shielding to ionizing radiation. Their small median angular size, of about 1 deg. FWHM, might then imply substantial distances, since the partially ionized HI skin in a power-law ionizing photon field has a typical exponential scale-length of 1 kpc. The automated search algorithm has been applied to the HIPASS and to the Leiden/Dwingeloo data sets. The results from the LDS are described here; Putman et al. (2002) describe application of this algorithm to the HIPASS material. We identify 67 CHVCs in the LDS which satisfy stringent requirements on isolation, and an additional 49 objects which satisfy somewhat less stringent requirements. Independent confirmation is available for all of these objects, either from earlier data in the literature or from new observations made with the Westerbork Synthesis Radio Telescope and reported here. The catalog includes 54 of the 65 CHVCs listed by Braun and Burton (1999) on the basis of a visual search of the LDS data.

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

    Broader source: Energy.gov [DOE]

    Improved seismic imaging of geology across high-velocity Earth surfaces will allow more rigorous evaluation of geothermal prospects beneath volcanic outcrops. Seismic-based quantification of fracture orientation and intensity will result in optimal positioning of geothermal wells.

  20. HIGH-VELOCITY LINE FORMING REGIONS IN THE TYPE Ia SUPERNOVA 2009ig

    SciTech Connect (OSTI)

    Marion, G. H.; Foley, Ryan J.; Challis, Peter; Kirshner, Robert P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Vinko, Jozsef; Wheeler, J. Craig; Silverman, Jeffrey M. [University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259 (United States); Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Brown, Peter J. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, 4242 AMU, College Station, TX 77843 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Garnavich, Peter [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Landsman, Wayne B. [Adnet Systems, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Parrent, Jerod T. [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Pritchard, Tyler A.; Roming, Peter W. A. [Department of Astronomy and Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802 (United States); Wang, Xiaofeng, E-mail: gmarion@cfa.harvard.edu [Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing 1,00084 (China)

    2013-11-01T23:59:59.000Z

    We report measurements and analysis of high-velocity (HVF) (>20,000 km s{sup –1}) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between –14 days and +13 days with respect to the time of maximum B-band luminosity (B-max). We identify lines of Si II, Si III, S II, Ca II, and Fe II that produce both HVF and photospheric-velocity (PVF) absorption features. SN 2009ig is unusual for the large number of lines with detectable HVF in the spectra, but the light-curve parameters correspond to a slightly overluminous but unexceptional SN Ia (M{sub B} = –19.46 mag and ?m{sub 15}(B) = 0.90 mag). Similarly, the Si II ?6355 velocity at the time of B-max is greater than 'normal' for an SN Ia, but it is not extreme (v{sub Si} = 13,400 km s{sup –1}). The –14 days and –13 days spectra clearly resolve HVF from Si II ?6355 as separate absorptions from a detached line forming region. At these very early phases, detached HVF are prevalent in all lines. From –12 days to –6 days, HVF and PVF are detected simultaneously, and the two line forming regions maintain a constant separation of about 8000 km s{sup –1}. After –6 days all absorption features are PVF. The observations of SN 2009ig provide a complete picture of the transition from HVF to PVF. Most SNe Ia show evidence for HVF from multiple lines in spectra obtained before –10 days, and we compare the spectra of SN 2009ig to observations of other SNe. We show that each of the unusual line profiles for Si II ?6355 found in early-time spectra of SNe Ia correlate to a specific phase in a common development sequence from HVF to PVF.

  1. A DETAILED KINEMATIC MAP OF CASSIOPEIA A'S OPTICAL MAIN SHELL AND OUTER HIGH-VELOCITY EJECTA

    SciTech Connect (OSTI)

    Milisavljevic, Dan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138 (United States); Fesen, Robert A., E-mail: dmilisav@cfa.harvard.edu [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

    2013-08-01T23:59:59.000Z

    We present three-dimensional (3D) kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A's optically bright ejecta populate a torus-like geometry tilted approximately 30 Degree-Sign with respect to the plane of the sky with a -4000 to +6000 km s{sup -1} radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding circumstellar material/interstellar medium environment suggest that this geometry and velocity asymmetry may not be faithfully representative of the remnant's true 3D structure or the kinematic properties of the original explosion. The majority of the optical ejecta are arranged in several well-defined and nearly circular ring-like structures with diameters between approximately 30'' (0.5 pc) and 2' (2 pc). These ejecta rings appear to be a common phenomenon of young core-collapse remnants and may be associated with post-explosion input of energy from plumes of radioactive {sup 56}Ni-rich ejecta that rise, expand, and compress non-radioactive material. Our optical survey encompasses Cas A's faint outlying ejecta knots and exceptionally high-velocity NE and SW streams of S-rich debris often referred to as ''jets''. These outer knots, which exhibit a chemical make-up suggestive of an origin deep within the progenitor star, appear to be arranged in opposing and wide-angle outflows with opening half-angles of Almost-Equal-To 40 Degree-Sign.

  2. High strain rate metalworking with vaporizing foil actuator: Control of flyer velocity by varying input energy and foil thickness

    SciTech Connect (OSTI)

    Vivek, A., E-mail: vivek.4@osu.edu; Hansen, S. R.; Daehn, Glenn S. [Department of Materials Science and Engineering, The Ohio State University, 2041, College Road, Columbus, Ohio 43210 (United States)

    2014-07-15T23:59:59.000Z

    Electrically driven rapid vaporization of thin metallic foils can generate a high pressure which can be used to launch flyers at high velocities. Recently, vaporizing foil actuators have been applied toward a variety of impulse-based metal working operations. In order to exercise control over this useful tool, it is imperative that an understanding of the effect of characteristics of the foil actuator on its ability for mechanical impulse generation is developed. Here, foil actuators made out of 0.0508 mm, 0.0762 mm, and 0.127 mm thick AA1145 were used for launching AA2024-T3 sheets of thickness 0.508 mm toward a photonic Doppler velocimeter probe. Launch velocities ranging between 300 m/s and 1100 m/s were observed. In situ measurement of velocity, current, and voltage assisted in understanding the effect of burst current density and deposited electrical energy on average pressure and velocity with foil actuators of various thicknesses. For the pulse generator, geometry, and flyer used here, the 0.0762 mm thick foil was found to be optimal for launching flyers to high velocities over short distances. Experimenting with annealed foil actuators resulted in no change in the temporal evolution of flyer velocity as compared to foil actuators of full hard temper. A physics-based analytical model was developed and found to have reasonable agreement with experiment.

  3. High Velocity Interparticle Collisions Driven by Ultrasound Tanya Prozorov, Ruslan Prozorov, and Kenneth S. Suslick*,

    E-Print Network [OSTI]

    Suslick, Kenneth S.

    the liquid at velocities above the speed of sound.1-4 Unusual sonochemical effects are induced by these shock velocity of colliding particles approaches half the speed of sound in the liquid.4 The low melting point@uiuc.edu Ultrasonic irradiation of liquids produces transient cavitation: the formation, growth, and implosive

  4. Energetic neutral atoms as the explanation for the high velocity hydrogen around HD 209458b

    E-Print Network [OSTI]

    M. Holmström; A. Ekenbäck; F. Selsis; T. Penz; H. Lammer; P. Wurz

    2008-02-20T23:59:59.000Z

    Absorption in the stellar Lyman-$\\alpha$ (Ly-$\\alpha$) line observed during the transit of the extrasolar planet HD 209458b reveals high velocity atomic hydrogen at great distances from the planet. This has been interpreted as hydrogen atoms escaping from the exosphere of the planet, possibly undergoing hydrodynamic blow-off, being accelerated by stellar radiation pressure. However, around solar system planets the production of energetic neutral atoms from charge exchange between solar wind protons and neutral hydrogen from the exospheres has been observed, and should also occur at extrasolar planets. Here we show that the measured transit-associated Ly-$\\alpha$ absorption can be explained by the interaction between the exosphere of HD 209458b and the stellar wind, and that radiation pressure alone cannot explain the observation. This is the first observation of energetic neutral atoms outside the solar system. Since the stellar wind protons are the source of the observed energetic neutral atoms, this provides a completely new method of probing stellar wind conditions, and our model suggests a slow and hot stellar wind near HD 209458b at the time of the observation.

  5. Searching for Dark Matter Annihilation in the Smith High-Velocity Cloud

    E-Print Network [OSTI]

    Alex Drlica-Wagner; German A. Gomez-Vargas; John W. Hewitt; Tim Linden; Luigi Tibaldo

    2014-06-30T23:59:59.000Z

    Recent observations suggest that some high-velocity clouds may be confined by massive dark matter halos. In particular, the proximity and proposed dark matter content of the Smith Cloud make it a tempting target for the indirect detection of dark matter annihilation. We argue that the Smith Cloud may be a better target than some Milky Way dwarf spheroidal satellite galaxies and use gamma-ray observations from the Fermi Large Area Telescope to search for a dark matter annihilation signal. No significant gamma-ray excess is found coincident with the Smith Cloud, and we set strong limits on the dark matter annihilation cross section assuming a spatially-extended dark matter profile consistent with dynamical modeling of the Smith Cloud. Notably, these limits exclude the canonical thermal relic cross section ($\\sim 3\\times10^{-26}{\\rm cm}^{3}{\\rm s}^{-1}$) for dark matter masses $\\lesssim 30$ GeV annihilating via the $b \\bar b$ or $\\tau^{+}\\tau^{-}$ channels for certain assumptions of the dark matter density profile; however, uncertainties in the dark matter content of the Smith Cloud may significantly weaken these constraints.

  6. Calculation and measurement of a neutral air flow velocity impacting a high voltage capacitor with asymmetrical electrodes

    SciTech Connect (OSTI)

    Malík, M., E-mail: michal.malik@tul.cz; Primas, J.; Kopecký, V.; Svoboda, M. [Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Liberec, 461 17 (Czech Republic)] [Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Liberec, 461 17 (Czech Republic)

    2014-01-15T23:59:59.000Z

    This paper deals with the effects surrounding phenomenon of a mechanical force generated on a high voltage asymmetrical capacitor (the so called Biefeld-Brown effect). A method to measure this force is described and a formula to calculate its value is also given. Based on this the authors derive a formula characterising the neutral air flow velocity impacting an asymmetrical capacitor connected to high voltage. This air flow under normal circumstances lessens the generated force. In the following part this velocity is measured using Particle Image Velocimetry measuring technique and the results of the theoretically calculated velocity and the experimentally measured value are compared. The authors found a good agreement between the results of both approaches.

  7. EROSIVE WEAR OF DUCTILE METALS BY A PARTICLE-LADEN HIGH-VELOCITY LIQUID-JET

    E-Print Network [OSTI]

    Li, Simon Ka-Keung

    2014-01-01T23:59:59.000Z

    of magnitude larger than by a coal slurry for erosion onlyand 1018 mild steel by coal slurry. Effect of velocity andvariation on erosion by coal slurry. Effect of material

  8. An all-sky study of compact, isolated high-velocity clouds

    E-Print Network [OSTI]

    V. de Heij; R. Braun; W. B. Burton

    2002-06-18T23:59:59.000Z

    We combine the catalogs of compact high-velocity HI clouds extracted from the LDS and HIPASS surveys and analyze the all-sky properties of the ensemble. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densities, (4) the number distribution of angular sizes, and (5) the number distribution of HI linewidth. Two classes of models are considered to reproduce the observed properties. The agreement of models with the data is judged by extracting these same observables from simulations, in a manner consistent with the sensitivities of the observations and explicitly taking account of Galactic obscuration. We show that models in which the CHVCs are the HI counterparts of dark-matter halos evolving in the Local Group potential provide a good match to the observables. The best-fitting populations have a maximum HI mass of 10^7 M_Sun a power-law slope of the HI mass distribution in the range -1.7 to -1.8, and a Gaussian dispersion for their spatial distributions of between 150 and 200 kpc centered on both the Milky Way and M31. Given its greater mean distance, only a small fraction of the M31 sub-population is predicted to have been detected in present surveys. An empirical model for an extended Galactic halo distribution for the CHVCs is also considered. While reproducing some aspects of the population, this class of models does not account for some key systematic features of the population.

  9. THE SMITH CLOUD: HIGH-VELOCITY ACCRETION AND DARK MATTER CONFINEMENT

    SciTech Connect (OSTI)

    Nichols, M.; Bland-Hawthorn, J., E-mail: m.nichols@physics.usyd.edu.a [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

    2009-12-20T23:59:59.000Z

    The Smith Cloud is a massive system of metal-poor neutral and ionized gas (M{sub gas} approx> 2 x 10{sup 6} M{sub sun}) that is presently moving at high velocity (V{sub GSR}approx 300 km s{sup -1}) with respect to the Galaxy at a distance of 12 kpc from the Sun. The kinematics of the cloud's cometary tail indicates that the gas is in the process of accretion onto the Galaxy, as first discussed by Lockman et al. Here, we re-investigate the cloud's orbit by considering the possibility that the cloud is confined by a dark matter halo. This is required for the cloud to survive its passage through the Galactic corona. We consider three possible models for the dark matter halo (Navarro-Frenk-White (NFW), Einasto, and Burkert) including the effects of tidal disruption and ram pressure stripping during the cloud's infall onto and passage through the Galactic disk. For the NFW and Einasto dark matter models, we are able to determine reasonable initial conditions for the Smith Cloud, although this is only marginally possible with the Burkert model. For all three models, the progenitor had an initial (gas+dark matter) mass that was an order-of-magnitude higher than inferred today. In agreement with Lockman et al., the cloud appears to have punched through the disk approx70 Myr ago. For our most successful models, the baryon-to-dark matter ratio is fairly constant during an orbital period but drops by a factor of 2-5 after transiting the disk. The cloud appears to have only marginally survived its transit and is unlikely to retain its integrity during the next transit approx 30 Myr from now.

  10. Feasibility and preliminary design study for a high velocity, low density wind tunnel utilizing the thermal creep effect

    E-Print Network [OSTI]

    Stephen, Alton Lee

    1968-01-01T23:59:59.000Z

    Average molecular velocity Cartesian length co-ordinate Thermal accomodation co-efficient Constant used in Appendix I Element of volume in velocity space Angular displacement Viscosity co-efficient Gas density cm cm/sec cm/sec cm/sec cm... on spheres in a rarefied gas as a means of making correc- tions to the results of Millikan's oil drop experiment. 4 Sanger's work was followed by a paper in which Tsien out- lined the field of low density, high speed gas dynamics. In this work, Tsien used...

  11. High-pressure sound velocities and elasticity of aluminous MgSiO3 perovskite to 45 GPa: Implications for lateral heterogeneity in Earth's

    E-Print Network [OSTI]

    Jackson, Jennifer M.

    High-pressure sound velocities and elasticity of aluminous MgSiO3 perovskite to 45 GPa lateral variations of seismic wave speeds in Earth's lower mantle are due at least in part to a chemical, J. M., J. Zhang, J. Shu, S. V. Sinogeikin, and J. D. Bass (2005), High-pressure sound velocities

  12. Geometry Effects on Multipole Components and Beam Optics in High-Velocity Multi-Spoke Cavities

    SciTech Connect (OSTI)

    Hopper, Christopher S. [ODU, JLAB; Deitrick, Kirsten E. [ODU, JLAB; Delayen, Jean R. [ODU, JLAB

    2013-12-01T23:59:59.000Z

    Velocity-of-light, multi-spoke cavities are being proposed to accelerate electrons in a compact light-source. There are strict requirements on the beam quality which require that the linac have only small non-uniformities in the accelerating field. Beam dynamics simulations have uncovered varying levels of focusing and defocusing in the proposed cavities, which is dependent on the geometry of the spoke in the vicinity of the beam path. Here we present results for the influence different spoke geometries have on the multipole components of the accelerating field and how these components, in turn, impact the simulated beam properties.

  13. Global well-posedness for the compressible Navier-Stokes equations with the highly oscillating initial velocity

    E-Print Network [OSTI]

    Qionglei Chen; Changxing Miao; Zhifei Zhang

    2009-08-02T23:59:59.000Z

    Cannone \\cite{Cannone} proved the global well-posedness of the incompressible Navier-Stokes equations for a class of highly oscillating data. In this paper, we prove the global well-posedness for the compressible Navier-Stokes equations in the critical functional framework with the initial data close to a stable equilibrium. Especially, this result allows us to construct global solutions for the highly oscillating initial velocity. The proof relies on a new estimate for the hyperbolic/parabolic system with convection terms.

  14. A Detailed Kinematic Map of Cassiopeia A's Optical Main Shell and Outer High-Velocity Ejecta

    E-Print Network [OSTI]

    Milisavljevic, Dan

    2013-01-01T23:59:59.000Z

    We present three-dimensional kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A's optically bright ejecta populate a torus-like geometry tilted approximately 30 degrees with respect to the plane of the sky with a -4000 to +6000 km/s radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding CSM/ISM environment suggest that this geometry and velocity asymmetry may not be faithfully representative of the remnant's true 3D structure or the kinematic properties of the original explosion. The majority of the optical ejecta are arranged in several well-defined and nearly circular ring-like structures with diameters between approximately 30 arcsec (0.5 pc) and 2 arcmin (2 pc). These ejecta rings app...

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

    SciTech Connect (OSTI)

    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

    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.

  16. A CATALOG OF ULTRA-COMPACT HIGH VELOCITY CLOUDS FROM THE ALFALFA SURVEY: LOCAL GROUP GALAXY CANDIDATES?

    SciTech Connect (OSTI)

    Adams, Elizabeth A. K.; Giovanelli, Riccardo; Haynes, Martha P., E-mail: betsey@astro.cornell.edu, E-mail: riccardo@astro.cornell.edu, E-mail: haynes@astro.cornell.edu [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States)

    2013-05-01T23:59:59.000Z

    We present a catalog of 59 ultra-compact high velocity clouds (UCHVCs) extracted from the 40% complete ALFALFA HI-line survey. The ALFALFA UCHVCs have median flux densities of 1.34 Jy km s{sup -1}, median angular diameters of 10', and median velocity widths of 23 km s{sup -1}. We show that the full UCHVC population cannot easily be associated with known populations of high velocity clouds. Of the 59 clouds presented here, only 11 are also present in the compact cloud catalog extracted from the commensal GALFA-HI survey, demonstrating the utility of this separate dataset and analysis. Based on their sky distribution and observed properties, we infer that the ALFALFA UCHVCs are consistent with the hypothesis that they may be very low mass galaxies within the Local Volume. In that case, most of their baryons would be in the form of gas, and because of their low stellar content, they remain unidentified by extant optical surveys. At distances of {approx}1 Mpc, the UCHVCs have neutral hydrogen (H I) masses of {approx}10{sup 5}-10{sup 6} M{sub Sun }, H I diameters of {approx}2-3 kpc, and indicative dynamical masses within the H I extent of {approx}10{sup 7}-10{sup 8} M{sub Sun }, similar to the Local Group ultra-faint dwarf Leo T. The recent ALFALFA discovery of the star-forming, metal-poor, low mass galaxy Leo P demonstrates that this hypothesis is true in at least one case. In the case of the individual UCHVCs presented here, confirmation of their extragalactic nature will require further work, such as the identification of an optical counterpart to constrain their distance.

  17. HIGH VELOCITY PRECESSING JETS FROM THE WATER FOUNTAIN IRAS 18286-0959 REVEALED BY VERY LONG BASELINE ARRAY OBSERVATIONS

    SciTech Connect (OSTI)

    Yung, Bosco H. K.; Nakashima, Jun-ichi; Kwok, Sun [Department of Physics, University of Hong Kong, Pokfulam Rd., Hong Kong (Hong Kong); Imai, Hiroshi [Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Deguchi, Shuji [Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Diamond, Philip J. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom)

    2011-11-10T23:59:59.000Z

    We report the results of multi-epoch Very Long Baseline Array observations of the 22.2 GHz H{sub 2}O maser emission associated with the 'water fountain' IRAS 18286-0959. We suggest that this object is the second example of a highly collimated bipolar precessing outflow traced by H{sub 2}O maser emission, the other is W 43A. The detected H{sub 2}O emission peaks are distributed over a velocity range from -50 km s{sup -1} to 150 km s{sup -1}. The spatial distribution of over 70% of the identified maser features is found to be highly collimated along a spiral jet (jet 1) extended southeast to northwest; the remaining features appear to trace another spiral jet (jet 2) with a different orientation. The two jets form a 'double-helix' pattern which lies across {approx}200 mas. The maser distribution is reasonably fit by a model consisting of two bipolar precessing jets. The three-dimensional velocities of jet 1 and jet 2 are derived to be 138 km s{sup -1} and 99 km s{sup -1}, respectively. The precession period of jet 1 is about 56 years. For jet 2, three possible models are tested and they give different values for the kinematic parameters. We propose that the appearance of two jets is the result of a single driving source with significant proper motion.

  18. GALACTIC ALL-SKY SURVEY HIGH-VELOCITY CLOUDS IN THE REGION OF THE MAGELLANIC LEADING ARM

    SciTech Connect (OSTI)

    For, Bi-Qing; Staveley-Smith, Lister [International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia)] [International Centre for Radio Astronomy Research, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia); McClure-Griffiths, N. M., E-mail: biqing.for@uwa.edu.au [Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW 1710 (Australia)

    2013-02-10T23:59:59.000Z

    We present a catalog of high-velocity clouds in the region of the Magellanic Leading Arm. The catalog is based on neutral hydrogen (H I) observations from the Parkes Galactic All-Sky Survey. Excellent spectral resolution allows clouds with narrow-line components to be resolved. The total number of detected clouds is 419. We describe the method of cataloging and present the basic parameters of the clouds. We discuss the general distribution of the high-velocity clouds and classify the clouds based on their morphological type. The presence of a significant number of head-tail clouds and their distribution in the region is discussed in the context of Magellanic System simulations. We suggest that ram-pressure stripping is a more important factor than tidal forces for the morphology and formation of the Magellanic Leading Arm and that different environmental conditions might explain the morphological difference between the Magellanic Leading Arm and Magellanic Stream. We also discuss a newly identified population of clouds that forms the LA IV and a new diffuse bridge-like feature connecting the LA II and III complexes.

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

    SciTech Connect (OSTI)

    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

    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.

  20. Compact High Velocity Clouds

    E-Print Network [OSTI]

    Robert Braun

    2000-09-01T23:59:59.000Z

    We summarize the observed properties of the CHVC population, which provide strong evidence for source distances in the range 200-1000 kpc. At these distances, the population corresponds to strongly dark-matter dominated sub-dwarf galaxies still accreting onto the more massive Local Group systems. Recent searches for faint associated stellar populations have revealed red-giant candidates for which follow-up spectroscopy is scheduled. A sensitive HI survey for CHVC counterparts in the NGC 628 galaxy group has allowed tentative detection of 40 candidates, for which confirming observations have been approved. Many open issues should be resolved by observational programs within the coming years.

  1. High velocity impact fracture

    E-Print Network [OSTI]

    Teng, Xiaoqing

    2005-01-01T23:59:59.000Z

    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 ...

  2. THE M81 GROUP DWARF IRREGULAR GALAXY DDO 165. I. HIGH-VELOCITY NEUTRAL GAS IN A POST-STARBURST SYSTEM

    SciTech Connect (OSTI)

    Cannon, John M.; Most, Hans P. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Skillman, Evan D.; Weisz, Daniel R.; Warren, Steven R. [Astronomy Department, University of Minnesota, Minneapolis, MN 55455 (United States); Cook, David [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Kennicutt, Robert C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Lee, Janice [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Seth, Anil [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Walter, Fabian, E-mail: jcannon@macalester.edu, E-mail: skillman@astro.umn.edu, E-mail: dweisz@astro.umn.edu, E-mail: warren@astro.umn.edu, E-mail: dcook12@uwyo.edu, E-mail: adolphin@raytheon.com, E-mail: robk@ast.cam.ac.uk, E-mail: jlee@obs.carnegiescience.edu, E-mail: aseth@cfa.harvard.edu, E-mail: walter@mpia.de [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany)

    2011-07-01T23:59:59.000Z

    We present new multi-configuration Very Large Array H I spectral line observations of the M81 group dwarf irregular post-starburst galaxy DDO 165. The H I morphology is complex, with multiple column density peaks surrounding a large region of very low H I surface density that is offset from the center of the stellar distribution. The bulk of the neutral gas is associated with the southern section of the galaxy; a secondary peak in the north contains {approx}15% of the total H I mass. These components appear to be kinematically distinct, suggesting that either tidal processes or large-scale blowout have recently shaped the interstellar medium (ISM) of DDO 165. Using spatially resolved position-velocity maps, we find multiple localized high-velocity gas features. Cross-correlating with radius-velocity analyses, we identify eight shell/hole structures in the ISM with a range of sizes ({approx}400-900 pc) and expansion velocities ({approx}7-11 km s{sup -1}). These structures are compared with narrow- and broadband imaging from the Kitt Peak National Observatory and the Hubble Space Telescope (HST). Using the latter data, recent works have shown that DDO 165's previous 'burst' phase was extended temporally ({approx}>1 Gyr). We thus interpret the high-velocity gas features, H I holes, and kinematically distinct components of the galaxy in the context of the immediate effects of 'feedback' from recent star formation (SF). In addition to creating H I holes and shells, extended SF events are capable of creating localized high-velocity motion of the surrounding interstellar material. A companion paper connects the energetics from the H I and HST data.

  3. Density, porosity, mineralogy, and internal structure of cosmic dust and alteration of its properties during high velocity atmospheric entry

    E-Print Network [OSTI]

    Kohout, T; Suuronen, J -P; Rochette, P; Hutzler, A; Gattacceca, J; Skála, D D Badjukov R; Böhmová, V; ?uda, J

    2014-01-01T23:59:59.000Z

    X-ray microtomography (XMT), X-ray diffraction (XRD) and magnetic hysteresis measurements were used to determine micrometeorite internal structure, mineralogy, crystallography, and physical properties at ~{\\mu}m resolution. The study samples include unmelted, partially melted (scoriaceous) and completely melted (cosmic spherules) micrometeorites. This variety not only allows comparison of the mineralogy and porosity of these three micrometeorite types, but also reveals changes in meteoroid properties during atmospheric entry at various velocities. At low entry velocities, meteoroids do not melt, and their physical properties do not change. The porosity of unmelted micrometeorites varies considerably (0-12%) with one friable example having porosity around 50%. At higher velocities, the range of meteoroid porosity narrows, but average porosity increases (to 16-27%) due to volatile evaporation and partial melting (scoriaceous phase). Metal distribution seems to be mostly unaffected at this stage. At even higher ...

  4. The radial-velocity revolution

    SciTech Connect (OSTI)

    Griffin, R. (Cambridge Univ., Observatories (England))

    1989-09-01T23:59:59.000Z

    Instruments and techniques designed for registering the minute Doppler shifts arising from stellar radial velocity are examined. Particular attention is given to the photographic spectrographs, the high-dispersion spectrographs ('digital speedometers'), and the Palomar spectrometer. The principle of using radial-velocity masks is described, and the use of interferometers for radial-velocity measurements is discussed. Results are presented of radial velocity observations for HD 114762, HD 210647, and Epsilon Tauri, together with interpretations of these results.

  5. MATTER MIXING IN ASPHERICAL CORE-COLLAPSE SUPERNOVAE: A SEARCH FOR POSSIBLE CONDITIONS FOR CONVEYING {sup 56}Ni INTO HIGH VELOCITY REGIONS

    SciTech Connect (OSTI)

    Ono, Masaomi; Nagataki, Shigehiro; Ito, Hirotaka; Lee, Shiu-Hang; Mao, Jirong; Tolstov, Alexey [Astrophysical Big Bang Laboratory, RIKEN, Saitama 351-0198 (Japan); Hashimoto, Masa-aki, E-mail: masaomi.ono@riken.jp [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

    2013-08-20T23:59:59.000Z

    We perform two-dimensional axisymmetric hydrodynamic simulations of matter mixing in aspherical core-collapse supernova explosions of a 16.3 M{sub Sun} star with a compact hydrogen envelope. Observations of SN 1987A have provided evidence that {sup 56}Ni synthesized by explosive nucleosynthesis is mixed into fast moving matter ({approx}>3500 km s{sup -1}) in the exploding star. In order to clarify the key conditions for reproducing such high velocity of {sup 56}Ni, we revisit matter mixing in aspherical core-collapse supernova explosions. Explosions are initiated artificially by injecting thermal and kinetic energies around the interface between the iron core and the silicon-rich layer. Perturbations of 5% or 30% amplitude in the radial velocities are introduced at several points in time. We find that no high velocity {sup 56}Ni can be obtained if we consider bipolar explosions with perturbations (5% amplitude) of pre-supernova origins. If large perturbations (30% amplitude) are introduced or exist due to some unknown mechanism in a later phase just before the shock wave reaches the hydrogen envelope, {sup 56}Ni with a velocity of 3000 km s{sup -1} can be obtained. Aspherical explosions that are asymmetric across the equatorial plane with clumpy structures in the initial shock waves are investigated. We find that the clump sizes affect the penetration of {sup 56}Ni. Finally, we report that an aspherical explosion model that is asymmetric across the equatorial plane with multiple perturbations of pre-supernova origins can cause the penetration of {sup 56}Ni clumps into fast moving matter of 3000 km s{sup -1}. We show that both aspherical explosions with clumpy structures and perturbations of pre-supernova origins may be necessary to reproduce the observed high velocity of {sup 56}Ni. To confirm this, more robust three-dimensional simulations are required.

  6. MEASUREMENTS OF VELOCITY PROFILES AND SUSPENDED-SEDIMENT CONCENTRATIONS IN A COLORADO RIVER EDDY DURING HIGH FLOW

    E-Print Network [OSTI]

    averaged; suspended sediment is modeled through use of the advection-dispersion equation which yieldsMEASUREMENTS OF VELOCITY PROFILES AND SUSPENDED-SEDIMENT CONCENTRATIONS IN A COLORADO RIVER EDDY profiles and suspended-sediment concentration were made in a recirculating eddy along the Colorado River

  7. 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 (OSTI)

    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

    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.

  8. 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 (OSTI)

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

    2008-01-29T23:59:59.000Z

    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 1 MHz 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 uclear-radiation background on the measurement uncertainties are calculated to predict performance on ITER.

  9. Recovery of uranium from seawater; 15: Development of amidoxime resins with high sedimentation velocity for passively driver fluidized bed adsorbers

    SciTech Connect (OSTI)

    Egawa, Hiroaki; Kabay, N.; Jyo, A.; Hirono, Masaki; Shuto, Taketomi (Kumamoto Univ. (Japan). Dept. of Applied Chemistry)

    1994-03-01T23:59:59.000Z

    In order to design the amidoxime resins (RNH) suitable for circulating fluidized bed adsorbers, RNH were prepared from precursory acrylonitrile-divinylbenzene copolymer beads of different particle sizes, and chemical and physical properties of the resulting RNH were evaluated. Specific surface areas, pore structures, swelling ratios, and anion and cation-exchange capacities of RNH are little affected by the particle size, while their sedimentation velocities in water increase with an increase in particle size as expected from fluid dynamics. Although the uptake of uncomplexed uranyl ion from a uranyl nitrate solution (0.01 M) was not influenced by the particle size, the uranium uptake from seawater decreases with an increase in the particle size, indicating that the particle diffusion of the bulky complexed species UO[sub 2](CO[sub 3])[sub 3][sup 4[minus

  10. The design and construction of a high-resolution velocity-map imaging apparatus for photoelectron spectroscopy studies of size-selected clusters

    SciTech Connect (OSTI)

    León, Iker; Yang, Zheng; Liu, Hong-Tao; Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)

    2014-08-15T23:59:59.000Z

    A new velocity-map imaging apparatus equipped with a laser-vaporization supersonic cluster source and a time-of-flight mass spectrometer is described for high-resolution photoelectron spectroscopy studies of size-selected cluster anions. Vibrationally cold anion clusters are produced using a laser-vaporization supersonic cluster source, size-selected by a time-of-flight mass spectrometer, and then focused co-linearly into the interaction zone of the high-resolution velocity-map imaging (VMI) system. The multilens VMI system is optimized via systematic simulations and can reach a resolution of 1.2 cm{sup ?1} (FWHM) for near threshold electrons while maintaining photoelectron kinetic energy resolutions (?KE/KE) of ?0.53% for higher energy electrons. The new VMI lens has superior focusing power over a large energy range, yielding highly circular images with distortions no larger than 1.0025 between the long and short radii. The detailed design, simulation, construction, testing, and performance of the high-resolution VMI apparatus are presented.

  11. Evaluation of asbestos dust concentration in discharge air from a high-velocity low-volume vacuum system

    E-Print Network [OSTI]

    Daniel, Steven Hall

    1977-01-01T23:59:59.000Z

    of high energy particles through polycarbonates) were selected because they have a very smooth surface which causes the fi bers to be easily distinguished under the scanning electron microscope (SEM). The results obtained by Beckett indicate...

  12. QUASI-PERIODIC PROPAGATING SIGNALS IN THE SOLAR CORONA: THE SIGNATURE OF MAGNETOACOUSTIC WAVES OR HIGH-VELOCITY UPFLOWS?

    SciTech Connect (OSTI)

    De Pontieu, Bart [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. ADBS, Bldg. 252, Palo Alto, CA 94304 (United States); McIntosh, Scott W., E-mail: bdp@lmsal.co, E-mail: mscott@ucar.ed [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2010-10-20T23:59:59.000Z

    Since the discovery of quasi-periodic propagating oscillations with periods of order 3-10 minutes in coronal loops with TRACE and SOHO/EIT (and later with STEREO/EUVI and Hinode/EIS), they have been almost universally interpreted as evidence for propagating slow-mode magnetoacoustic waves in the low plasma {beta} coronal environment. Here we show that this interpretation is not unique, and that for coronal loops associated with plage regions (as opposed to sunspots), the presence of magnetoacoustic waves may not be the only cause for the observed quasi-periodicities. We focus instead on the ubiquitous, faint upflows at 50-150 km s{sup -1} that were recently discovered as blueward asymmetries of spectral line profiles in footpoint regions of coronal loops, and as faint disturbances propagating along coronal loops in EUV/X-ray imaging time series. These faint upflows are most likely driven from below and have been associated with chromospheric jets that are (partially) rapidly heated to coronal temperatures at low heights. These two scenarios (waves versus flows) are difficult to differentiate using only imaging data, but careful analysis of spectral line profiles indicates that faint upflows are likely responsible for some of the observed quasi-periodic oscillatory signals in the corona. We show that recent EIS measurements of intensity and velocity oscillations of coronal lines (which had previously been interpreted as direct evidence for propagating waves) are actually accompanied by significant oscillations in the line width that are driven by a quasi-periodically varying component of emission in the blue wing of the line. This faint additional component of blue-shifted emission quasi-periodically modulates the peak intensity and line centroid of a single Gaussian fit to the spectral profile with the same small amplitudes (respectively a few percent of background intensity and a few km s{sup -1}) that were previously used to infer the presence of slow-mode magnetoacoustic waves. Our results indicate that it is possible that a significant fraction of the quasi-periodicities observed with coronal imagers and spectrographs that have previously been interpreted as propagating magnetoacoustic waves are instead caused by these upflows. The different physical cause for coronal oscillations would significantly impact the prospects of successful coronal seismology using propagating disturbances in coronal loops.

  13. The structural and mechanical properties of a Cu??Zr??(at. %) alloy processed by High-Velocity-Injection (HVI)

    E-Print Network [OSTI]

    Hays, Charles C.

    1986-01-01T23:59:59.000Z

    /vacuum coupled pressure gradient. The molten jet rapidly solidifies, as it is in good thermal contact wi th the cir- cular walls of the copper channel. This process (melting and injection) is carried out in inert protective atmospheres (helium). The samples... produced are in the form of cylindrical rods with large length to diameter ratios (40:1). The samples exhibit a good sur- face finish and are of high density. The structural and mechanical characterization of the Cu6 Zr 0(at. %%u) samples produced...

  14. Study of Chelyabinsk LL5 meteorite fragment with a light lithology and its fusion crust using Mössbauer spectroscopy with a high velocity resolution

    SciTech Connect (OSTI)

    Maksimova, Alevtina A.; Petrova, Evgeniya V.; Grokhovsky, Victor I. [Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002 (Russian Federation); Oshtrakh, Michael I., E-mail: oshtrakh@gmail.com; Semionkin, Vladimir A. [Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology, Ural Federal University, Ekaterinburg, 620002, Russian Federation and Department of Experimental Physics, Institute of Physics and Technology, Ura (Russian Federation)

    2014-10-27T23:59:59.000Z

    Study of Chelyabinsk LL5 ordinary chondrite fragment with a light lithology and its fusion crust, fallen on February 15, 2013, in Russian Federation, was carried out using Mössbauer spectroscopy with a high velocity resolution. The Mössbauer spectra of the internal matter and fusion crust were fitted and all components were related to iron-bearing phases such as olivine, pyroxene, troilite, Fe-Ni-Co alloy, and chromite in the internal matter and olivine, pyroxene, troilite, Fe-Ni-Co alloy, and magnesioferrite in the fusion crust. A comparison of the content of different phases in the internal matter and in the fusion crust of this fragment showed that ferric compounds resulted from olivine, pyroxene, and troilite combustion in the atmosphere.

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

    SciTech Connect (OSTI)

    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

    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.

  16. Cold Climate and Retrofit Applications for Air-to-Air Heat Pumps

    SciTech Connect (OSTI)

    Baxter, Van D [ORNL

    2015-01-01T23:59:59.000Z

    Air source heat pumps (ASHP) including air-to-air ASHPs are easily applied to buildings almost anywhere for new construction as well as retrofits or renovations. They are widespread in milder climate regions but their use in cold regions is hampered due to low heating efficiency and capacity at cold outdoor temperatures. Retrofitting air-to-air ASHPs to existing buildings is relatively easy if the building already has an air distribution system. For buildings without such systems alternative approaches are necessary. Examples are ductless, minisplit heat pumps or central heat pumps coupled to small diameter, high velocity (SDHV) air distribution systems. This article presents two subjects: 1) a summary of R&D investigations aimed at improving the cold weather performance of ASHPs, and 2) a brief discussion of building retrofit options using air-to-air ASHP systems.

  17. Keck-I MOSFIRE spectroscopy of compact star-forming galaxies at z$\\gtrsim$2: High velocity dispersions in progenitors of compact quiescent galaxies

    E-Print Network [OSTI]

    Barro, G; Koo, D C; Dekel, A; Kassin, S A; Kocevski, D D; Faber, S M; van der Wel, A; Guo, Y; Perez-Gonzalez, P G; Toloba, E; Fang, J J; Pacifici, C; Simons, R; Campbell, R D; Ceverino, D; Finkelstein, S L; Goodrich, B; Kassis, M; Koekemoer, A M; Konidaris, N P; Livermore, R C; Lyke, J E; Mobasher, B; Nayyeri, H; Peth, M; Primack, J R; Rizzi, L; Somerville, R S; Wirth, G D; Zolotov, A

    2014-01-01T23:59:59.000Z

    We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift $2\\leq z \\leq2.5$ with star formation rates of SFR$\\sim$100M$_{\\odot}$ y$^{-1}$ and masses of log(M/M$_{\\odot}$)$\\sim10.8$. Their high integrated gas velocity dispersions of $\\sigma_{\\rm{int}}$=230$^{+40}_{-30}$ km s$^{-1}$, as measured from emission lines of H$_{\\alpha}$ and [OIII], and the resultant M$_{\\star}-\\sigma_{\\rm{int}}$ relation and M$_{\\star}$$-$M$_{\\rm{dyn}}$ all match well to those of compact quiescent galaxies at $z\\sim2$, as measured from stellar absorption lines. Since log(M$_{\\star}$/M$_{\\rm{dyn}}$)$=-0.06\\pm0.2$ dex, these compact SFGs appear to be dynamically relaxed and more evolved, i.e., more depleted in gas and dark matter ($infusion of external gas, depletion timescales are short, less than $\\sim$300 Myr. This discovery adds another link to our new dynamical chain of evidence...

  18. Unitaxial constant velocity microactuator

    DOE Patents [OSTI]

    McIntyre, T.J.

    1994-06-07T23:59:59.000Z

    A uniaxial drive system or microactuator capable of operating in an ultra-high vacuum environment is disclosed. 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-nanometer 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. 10 figs.

  19. Unitaxial constant velocity microactuator

    DOE Patents [OSTI]

    McIntyre, Timothy J. (Knoxville, TN)

    1994-01-01T23:59:59.000Z

    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.

  20. Report of IAU Commission 30 on Radial Velocities (2009-2012)

    E-Print Network [OSTI]

    Torres, G; Lovis, C; Marcy, G W; Mathieu, R D; Mazeh, T; Meibom, S; Minniti, D; Moutou, C; Pepe, F; Pourbaix, D; Turon, C; Udry, S; Zwitter, T

    2011-01-01T23:59:59.000Z

    Brief summaries are given of the following subjects of interest to IAU Commission 30: Large-scale radial-velocity surveys; The role of radial-velocity measurements in studies of stellar angular momentum evolution and stellar age; Radial velocities in open clusters; Toward higher radial-velocity precision; High-precision radial velocities applied to studies of binary stars; Doppler boosting effect; Working groups (Stellar radial velocity bibliography; Radial velocity standards; Catalogue of orbital elements of spectroscopic binaries [SB9]).

  1. Velocity pump reaction turbine

    DOE Patents [OSTI]

    House, Palmer A. (Walnut Creek, CA)

    1982-01-01T23:59:59.000Z

    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.

  2. Velocity pump reaction turbine

    DOE Patents [OSTI]

    House, Palmer A. (Walnut Creek, CA)

    1984-01-01T23:59:59.000Z

    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.

  3. Microstructure Development during High-Velocity Deformation P.J. FERREIRA, J.B. VANDER SANDE, M. AMARAL FORTES, and A. KYROLAINEN

    E-Print Network [OSTI]

    Ferreira, Paulo J.

    industries. In the automotive industry, an understanding of the mechanisms occurring dur- ing high was observed without failure in iron, cop- per, and aluminum sheets)[1,2] as well as significant strain

  4. Terminal Velocity Infall in QSO Absorption Line Halos

    E-Print Network [OSTI]

    Robert A. Benjamin

    1998-11-04T23:59:59.000Z

    We explore the hypothesis that clouds detected in quasar absorption line systems are falling at a terminal velocity toward the center of high redshift gaseous galactic halos. Since both the ionization level and terminal velocity of halo clouds increase with increasing distance from the central galaxy, velocity resolved profiles of highly ionized gas are predicted to have a greater width than low ionization gas. A line of sight passing through the center of gaseous halo (an idealized damped Ly alpha system), yields low ionization absorption at the velocity of the galaxy, flanked by high ionization on either side. Reasonable halo parameters yield total velocity extents for C IV of v_{C IV}=100-200 km/s, in agreement with several observed systems. The remaining systems may better described by the rotating disk model of Prochaska & Wolfe (1998). Finally, observational tests are suggested for verifying or falsifying the terminal velocity hypothesis for these systems.

  5. Apparatus and method for laser velocity interferometry

    DOE Patents [OSTI]

    Stanton, Philip L. (Bernalillo County, NM); Sweatt, William C. (Albuquerque, NM); Crump, Jr., O. B. (Albuquerque, NM); Bonzon, Lloyd L. (Albuquerque, NM)

    1993-09-14T23:59:59.000Z

    An apparatus and method for laser velocity interferometry employing a fixed interferometer cavity and delay element. The invention permits rapid construction of interferometers that may be operated by those non-skilled in the art, that have high image quality with no drift or loss of contrast, and that have long-term stability even without shock isolation of the cavity.

  6. Velocity Dispersions Across Bulge Types

    SciTech Connect (OSTI)

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich [University Observatory of the Ludwig-Maximilians University (LMU) (Germany); Max-Planck Institute for Extraterrestrial Physics (MPE) (Germany); Saglia, Roberto; Drory, Niv [Max-Planck Institute for Extraterrestrial Physics (MPE) (Germany); Fisher, David [Department of Astronomy, University of Texas at Austin (United States)

    2010-06-08T23:59:59.000Z

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (sigma*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  7. Is there Lower Limit to Velocity or Velocity Change?

    E-Print Network [OSTI]

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

    2013-06-19T23:59:59.000Z

    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.

  8. Note: A helical velocity selector for continuous molecular beams

    SciTech Connect (OSTI)

    Szewc, Carola; Collier, James D.; Ulbricht, Hendrik [School of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ (United Kingdom)

    2010-10-15T23:59:59.000Z

    We report on a modern realization of the classic helical velocity selector for gas phase particle beams. The device operates stably under high vacuum conditions at rotational frequencies limited only by commercial dc motor capabilities. Tuning the rotational frequency allows selective scanning over a broad velocity band. The width of the selected velocity distributions at full-width-half-maximum is as narrow as a few percent of the selected mean velocity and independent of the rotational speed of the selector. The selector generates low vibrational noise amplitudes comparable to mechanically damped state-of-the-art turbo-molecular pumps and is therefore compatible with vibration sensitive experiments like molecule interferometry.

  9. Line bisectors and radial velocity jitter from SARG spectra

    E-Print Network [OSTI]

    A. F. Martinez Fiorenzano; R. G. Gratton; S. Desidera; R. Cosentino; M. Endl

    2005-08-03T23:59:59.000Z

    We present an analysis of spectral line bisector variations for a few stars observed in the SARG high precision radial velocity planet survey, and discuss their relationship with differential radial velocities. The spectra we consider are the same used for determining radial velocities. The iodine cell lines employed in the measurement of radial velocities were removed before bisector analysis. The line bisectors were then computed from average absorption profiles obtained by cross correlation of the stellar spectra with a mask made from suitable lines of a solar catalog. Bisector velocity spans were then determined: errors in these quantities compare well with theoretical expectations based on resolution, S/N and line shape. The plot of bisector velocity span against radial velocity was studied to search for correlations between line asymmetries and radial velocity variations. A correlation was seen for HD 166435 due to stellar activity, and for HD 8071B due to spectral contamination by the companion. No correlation was seen for 51 Peg and rho CrB, stars hosting planets. We conclude that this technique may be useful to separate radial velocity variations due to barycenter motion from spurious signals in spectra acquired with the iodine cell.

  10. GMTI radar minimum detectable velocity.

    SciTech Connect (OSTI)

    Richards, John Alfred

    2011-04-01T23:59:59.000Z

    Minimum detectable velocity (MDV) is a fundamental consideration for the design, implementation, and exploitation of ground moving-target indication (GMTI) radar imaging modes. All single-phase-center air-to-ground radars are characterized by an MDV, or a minimum radial velocity below which motion of a discrete nonstationary target is indistinguishable from the relative motion between the platform and the ground. Targets with radial velocities less than MDV are typically overwhelmed by endoclutter ground returns, and are thus not generally detectable. Targets with radial velocities greater than MDV typically produce distinct returns falling outside of the endoclutter ground returns, and are thus generally discernible using straightforward detection algorithms. This document provides a straightforward derivation of MDV for an air-to-ground single-phase-center GMTI radar operating in an arbitrary geometry.

  11. Velocity requirements for causality violation

    E-Print Network [OSTI]

    Giovanni Modanese

    2015-01-18T23:59:59.000Z

    We re-examine the "Regge-Tolman paradox" with reference to some recent experimental results. It is straightforward to find a formula for the velocity v of the moving system required to produce causality violation. This formula typically yields a velocity very close to the speed of light (for instance, v/c > 0.97 for X-shaped microwaves), which raises some doubts about the real physical observability of the violations. We then compute the velocity requirement introducing a delay between the reception of the primary signal and the emission of the secondary. It turns out that in principle for any delay it is possible to find moving observers able to produce active causal violation. This is mathematically due to the singularity of the Lorentz transformations for beta to 1. For a realistic delay due to the propagation of a luminal precursor, we find that causality violations in the reported experiments are still more unlikely (v/c > 0.989), and even in the hypothesis that the superluminal propagation velocity goes to infinity, the velocity requirement is bounded by v/c > 0.62. We also prove that if two macroscopic bodies exchange energy and momentum through superluminal signals, then the swap of signal source and target is incompatible with the Lorentz transformations; therefore it is not possible to distinguish between source and target, even with reference to a definite reference frame.

  12. 3D Velocity from 3D Doppler Radial Velocity J. L. Barron,1

    E-Print Network [OSTI]

    Barron, John

    to compute local 3D velocity (local 3D optical flow). Radial velocity (measured by the Doppler effect3D Velocity from 3D Doppler Radial Velocity J. L. Barron,1 R. E. Mercer,1 X. Chen,1 P. Joe2 1 velocity data and qualitatively on real radial velocity data, obtained from the Doppler radar at Kurnell

  13. Low Velocity Boron Micro-Pellet Injector For Edge And Core Impurity Transport Measurements

    E-Print Network [OSTI]

    1 Low Velocity Boron Micro-Pellet Injector For Edge And Core Impurity Transport Measurements H. W, Baltimore, Maryland 21218 Abstract A simple Low Velocity Boron Micro-Pellet Injector has been under High velocity, pneumatic, pellet injection systems are applied routinely for injecting frozen pellets

  14. Radial velocities of southern visual multiple stars

    SciTech Connect (OSTI)

    Tokovinin, Andrei [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Pribulla, Theodor [Astronomical Institute, Slovak Academy of Sciences, 059 60 Tatranská Lomnica (Slovakia); Fischer, Debra, E-mail: atokovinin@ctio.noao.edu, E-mail: pribulla@ta3.sk, E-mail: debra.fischer@gmail.com [Department of Astronomy, Yale University, New Haven, CT 06511 (United States)

    2015-01-01T23:59:59.000Z

    High-resolution spectra of visual multiple stars were taken in 2008–2009 to detect or confirm spectroscopic subsystems and to determine their orbits. Radial velocities of 93 late-type stars belonging to visual multiple systems were measured by numerical cross-correlation. We provide the individual velocities, the width, and the amplitude of the Gaussians that approximate the correlations. The new information on the multiple systems resulting from these data is discussed. We discovered double-lined binaries in HD 41742B, HD 56593C, and HD 122613AB, confirmed several other known subsystems, and constrained the existence of subsystems in some visual binaries where both components turned out to have similar velocities. The orbits of double-lined subsystems with periods of 148 and 13 days are computed for HD 104471 Aa,Ab and HD 210349 Aa,Ab, respectively. We estimate individual magnitudes and masses of the components in these triple systems and update the outer orbit of HD 104471 AB.

  15. CO and IRAS detection of an intermediate-velocity cloud

    SciTech Connect (OSTI)

    Desert, F.X.; Bazell, D.; Blitz, L. (Paris Observatoire, Meudon (France) Space Telescope Science Institute, Baltimore, MD (USA) Maryland Univ., College Park (USA))

    1990-06-01T23:59:59.000Z

    In the course of a radio survey of high-Galactic-latitude clouds, CO emission was detected at the position l = 210.8 deg and b = 63.1 deg with an LSR velocity of -39 km/sec. This molecular cloud constitutes the third one with an unusually large absolute velocity at these latitudes, as compared with the 5.4-km/sec cloud-to-cloud velocity dispersion of the high-latitude molecular clouds. The position is coincident with an H I intermediate-velocity cloud (GHL 11, Verschuur H, OLM 268) and the IR-excess cloud 306 in the list by Desert et al. (1988). This cloud is clearly detected at all four IRAS wavelengths and has warmer colors than the local ISM. 27 refs.

  16. SHIP VELOCITY FIELDS , Lichuan Guib

    E-Print Network [OSTI]

    Gui, Lichuan

    directions. 1. Introduction Knowledge of flow around ships is important for design, model development, and computational fluid dynamics (CFD) validation. Historically, five-hole pitot probes have been used for measuring of multi-hole pitot and Laser-doppler systems, they both require measurement of ship velocity fields

  17. Velocity Distributions from Nonextensive Thermodynamics

    E-Print Network [OSTI]

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

    2006-10-05T23:59:59.000Z

    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)

  18. Pore fluid effects on seismic velocity in anisotropic rocks

    SciTech Connect (OSTI)

    Mukerji, T.; Mavko, G. (Stanford Univ., CA (United States). Dept. of Geophysics)

    1994-02-01T23:59:59.000Z

    A simple new technique predicts the high- and low-frequency saturated velocities in anisotropic rocks entirely in terms of measurable dry rock properties without the need for idealized crack geometries. Measurements of dry velocity versus pressure and porosity versus pressure contain all of the necessary information for predicting the frequency-dependent effects of fluid saturation. Furthermore, these measurements automatically incorporate all pore interaction, so there is no limitation to low crack density. The velocities are found to depend on five key interrelated variables: frequency, the distribution of compliant crack-like porosity, the intrinsic or noncrack anisotropy, fluid viscosity and compressibility, and effective pressure. The sensitivity of velocities to saturation is generally greater at high frequencies than low frequencies. The magnitude of the differences from dry to saturated and from low frequency to high frequency is determined by the compliant or crack-like porosity. Predictions of saturated velocities based on dry data for sandstone and granite show that compressional velocities generally increase with saturation and with frequency. However, the degree of compressional wave anisotropy may either increase or decrease upon saturation depending on the crack distribution, the effective pressure, and the frequency at which the measurements are made. Shear-wave velocities can either increase or decrease with saturation, and the degree of anisotropy depends on the microstructure, pressure, and frequency. Consequently great care must be taken when interpreting observed velocity anisotropy for measurements at low frequencies, typical of in situ observations, will generally be different from those at high frequencies, typical of the laboratory.

  19. BENCAP, LLC: CAPSULE VELOCITY TEST

    SciTech Connect (OSTI)

    Meidinger, Brian

    2005-09-07T23:59:59.000Z

    Ben Cap, LLC, has a technology that utilizes bebtonite to plug wells. The bentonite is encapsulated in a cardboard capsule, droped down to the bottom of the well where it is allowed to hydrate, causing the bentonite to expand and plug the well. This method of plugging a well is accepted in some, but not all states. This technology can save a significant amount of money when compared to cementing methods currently used to plug and abandon wells. The test objective was to obtain the terminal velocity of the capsule delivery system as it drops through a column of water in a wellbore. Once the terminal velocity is known, the bentonite swelling action can be timed not to begin swelling until it reaches the bottom of the well bore. The results of the test showed that an average speed of 8.93 plus or minus 0.12 ft/sec was achieved by the capsule as it was falling through a column of water. Plotting the data revealed a very linear function with the capsules achieving terminal velocity shortly after being released. The interference of the capsule impacting the casing was not readily apparent in any of the runs, but a siginal sampling anomaly was present in one run. Because the anomaly was so brief and not present in any of the other runs, no solid conclusions could be drawn. Additional testing would be required to determine the effects of capsules impacting a fluid level that is not at surface.

  20. Supersonic relative velocity effect on the baryonic acoustic oscillation measurements

    SciTech Connect (OSTI)

    Yoo, Jaiyul; Seljak, Uroš [Institute for Theoretical Physics, University of Zürich, CH-8057 Zürich (Switzerland); Dalal, Neal, E-mail: jyoo@physik.uzh.ch, E-mail: neal@cita.utoronto.ca, E-mail: seljak@physik.uzh.ch [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Ontario, M5S 3H8 (Canada)

    2011-07-01T23:59:59.000Z

    We investigate the effect of supersonic relative velocities between baryons and dark matter, recently shown to arise generically at high redshift, on baryonic acoustic oscillation (BAO) measurements at low redshift. The amplitude of the relative velocity effect at low redshift is model-dependent, but can be parameterized by using an unknown bias. We find that if unaccounted, the relative velocity effect can shift the BAO peak position and bias estimates of the dark energy equation-of-state due to its non-smooth, out-of-phase oscillation structure around the BAO scale. Fortunately, the relative velocity effect can be easily modeled in constraining cosmological parameters without substantially inflating the error budget. We also demonstrate that the presence of the relative velocity effect gives rise to a unique signature in the galaxy bispectrum, which can be utilized to isolate this effect. Future dark energy surveys can accurately measure the relative velocity effect and subtract it from the power spectrum analysis to constrain dark energy models with high precision.

  1. The Systemic Velocity of Eta Carinae

    E-Print Network [OSTI]

    Nathan Smith

    2004-06-23T23:59:59.000Z

    High-resolution spectra of molecular hydrogen in the Homunculus nebula allow for the first direct measurement of the systemic velocity of Eta Carinae. Near-infrared long-slit data for H2 1-0 S(1) lambda 21218 obtained with the Phoenix spectrometer on the Gemini South telescope give Vsys=-8.1pm1 km/s (heliocentric), or VLSR=-19.7pm1 km/s, from the average of the near and far sides of the Homunculus. This measurement considerably improves the precision for the value of -7pm10 km/s inferred from neighboring O-type stars in the Carina nebula. New near-infrared spectra also provide a high-resolution line profile of [Fe II] lambda 16435 emission from gas condensations known as the Weigelt objects without contamination from the central star, revealing a line shape with complex kinematic structure. Previously, uncertainty in the Weigelt knots' kinematics was dominated by the adopted systemic velocity of Eta Car.

  2. Effects of increasing tip velocity on wind turbine rotor design.

    SciTech Connect (OSTI)

    Resor, Brian Ray; Maniaci, David Charles; Berg, Jonathan Charles; Richards, Phillip William

    2014-05-01T23:59:59.000Z

    A reduction in cost of energy from wind is anticipated when maximum allowable tip velocity is allowed to increase. Rotor torque decreases as tip velocity increases and rotor size and power rating are held constant. Reduction in rotor torque yields a lighter weight gearbox, a decrease in the turbine cost, and an increase in the capacity for the turbine to deliver cost competitive electricity. The high speed rotor incurs costs attributable to rotor aero-acoustics and system loads. The increased loads of high speed rotors drive the sizing and cost of other components in the system. Rotor, drivetrain, and tower designs at 80 m/s maximum tip velocity and 100 m/s maximum tip velocity are created to quantify these effects. Component costs, annualized energy production, and cost of energy are computed for each design to quantify the change in overall cost of energy resulting from the increase in turbine tip velocity. High fidelity physics based models rather than cost and scaling models are used to perform the work. Results provide a quantitative assessment of anticipated costs and benefits for high speed rotors. Finally, important lessons regarding full system optimization of wind turbines are documented.

  3. Optic-microwave mixing velocimeter for superhigh velocity measurement

    SciTech Connect (OSTI)

    Weng Jidong; Wang Xiang; Tao Tianjiong; Liu Cangli; Tan Hua [Laboratory for Shock Waves and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, Mianyang, Sichuan 621900 (China)

    2011-12-15T23:59:59.000Z

    The phenomenon that a light beam reflected off a moving object experiences a Doppler shift in its frequency underlies practical interferometric techniques for remote velocity measurements, such as velocity interferometer system for any reflector (VISAR), displacement interferometer system for any reflector (DISAR), and photonic Doppler velocimetry (PDV). While VISAR velocimeters are often bewildered by the fringe loss upon high-acceleration dynamic process diagnosis, the optic-fiber velocimeters such as DISAR and PDV, on the other hand, are puzzled by high velocity measurement over 10 km/s, due to the demand for the high bandwidth digitizer. Here, we describe a new optic-microwave mixing velocimeter (OMV) for super-high velocity measurements. By using currently available commercial microwave products, we have constructed a simple, compact, and reliable OMV device, and have successfully obtained, with a digitizer of bandwidth 6 GH only, the precise velocity history of an aluminum flyer plate being accelerated up to 11.2 km/s in a three stage gas-gun experiment.

  4. Newberry EGS Seismic Velocity Model

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Templeton, Dennise

    We use ambient noise correlation (ANC) to create a detailed image of the subsurface seismic velocity at the Newberry EGS site down to 5 km. We collected continuous data for the 22 stations in the Newberry network, together with 12 additional stations from the nearby CC, UO and UW networks. The data were instrument corrected, whitened and converted to single bit traces before cross correlation according to the methodology in Benson (2007). There are 231 unique paths connecting the 22 stations of the Newberry network. The additional networks extended that to 402 unique paths crossing beneath the Newberry site.

  5. Newberry EGS Seismic Velocity Model

    SciTech Connect (OSTI)

    Templeton, Dennise

    2013-10-01T23:59:59.000Z

    We use ambient noise correlation (ANC) to create a detailed image of the subsurface seismic velocity at the Newberry EGS site down to 5 km. We collected continuous data for the 22 stations in the Newberry network, together with 12 additional stations from the nearby CC, UO and UW networks. The data were instrument corrected, whitened and converted to single bit traces before cross correlation according to the methodology in Benson (2007). There are 231 unique paths connecting the 22 stations of the Newberry network. The additional networks extended that to 402 unique paths crossing beneath the Newberry site.

  6. MEMS BASED DOPPLER VELOCITY MEASUREMENT SYSTEM

    E-Print Network [OSTI]

    White, Robert D.

    .2 Doppler Effect...................................................................................10 2MEMS BASED DOPPLER VELOCITY MEASUREMENT SYSTEM A dissertation submitted by Minchul Shin IN PARTIAL micromachined ultrasonic transducer (cMUT) based in-air Doppler velocity measurement system using a 1 cm2 planar

  7. Noise pair velocity and range echo location system

    DOE Patents [OSTI]

    Erskine, D.J.

    1999-02-16T23:59:59.000Z

    An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution is disclosed. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna. 46 figs.

  8. Noise pair velocity and range echo location system

    DOE Patents [OSTI]

    Erskine, David J. (Oakland, CA)

    1999-01-01T23:59:59.000Z

    An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna.

  9. Radial Velocity Variability of Field Brown Dwarfs

    E-Print Network [OSTI]

    Prato, L; Rice, E L; McLean, I S; Kirkpatrick, J D; Burgasser, A J; Kim, S S

    2015-01-01T23:59:59.000Z

    We present paper six of the NIRSPEC Brown Dwarf Spectroscopic Survey, an analysis of multi-epoch, high-resolution (R~20,000) spectra of 25 field dwarf systems (3 late-type M dwarfs, 16 L dwarfs, and 6 T dwarfs) taken with the NIRSPEC infrared spectrograph at the W. M. Keck Observatory. With a radial velocity precision of ~2 km/s, we are sensitive to brown dwarf companions in orbits with periods of a few years or less given a mass ratio of 0.5 or greater. We do not detect any spectroscopic binary brown dwarfs in the sample. Given our target properties, and the frequency and cadence of observations, we use a Monte Carlo simulation to determine the detection probability of our sample. Even with a null detection result, our 1 sigma upper limit for very low mass binary frequency is 18%. Our targets included 7 known, wide brown dwarf binary systems. No significant radial velocity variability was measured in our multi-epoch observations of these systems, even for those pairs for which our data spanned a significant ...

  10. Transit Detection of Radial Velocity Planets

    E-Print Network [OSTI]

    Stephen R. Kane; Kaspar von Braun

    2008-06-30T23:59:59.000Z

    The orbital parameters of extra-solar planets have a significant impact on the probability that the planet will transit the host star. This was recently demonstrated by the transit detection of HD 17156b whose favourable eccentricity and argument of periastron dramatically increased its transit likelihood. We present a study which provides a quantitative analysis of how these two orbital parameters effect the geometric transit probability as a function of period. Further, we apply these results to known radial velocity planets and show that there are unexpectedly high transit probabilities for planets at relatively long periods. For a photometric monitoring campaign which aims to determine if the planet indeed transits, we calculate the significance of a null result and the subsequent constraints that may be applied to orbital parameters.

  11. Tangential velocity measurement using interferometric MTI radar

    DOE Patents [OSTI]

    Doerry, Armin W.; Mileshosky, Brian P.; Bickel, Douglas L.

    2006-01-03T23:59:59.000Z

    Radar systems use time delay measurements between a transmitted signal and its echo to calculate range to a target. Ranges that change with time cause a Doppler offset in phase and frequency of the echo. Consequently, the closing velocity between target and radar can be measured by measuring the Doppler offset of the echo. The closing velocity is also known as radial velocity, or line-of-sight velocity. Doppler frequency is measured in a pulse-Doppler radar as a linear phase shift over a set of radar pulses during some Coherent Processing Interval (CPI). An Interferometric Moving Target Indicator (MTI) radar can be used to measure the tangential velocity component of a moving target. Multiple baselines, along with the conventional radial velocity measurement, allow estimating the true 3-D velocity of a target.

  12. Constraints on Neutrino Velocities Revisited

    E-Print Network [OSTI]

    Yunjie Huo; Tianjun Li; Yi Liao; Dimitri V. Nanopoulos; Yonghui Qi

    2012-01-27T23:59:59.000Z

    With a minimally modified dispersion relation for neutrinos, we reconsider the constraints on superluminal neutrino velocities from bremsstrahlung effects in the laboratory frame. Employing both the direct calculation approach and the virtual Z-boson approach, we obtain the generic decay width and energy loss rate of a superluminal neutrino with general energy. The Cohen-Glashow's analytical results for neutrinos with a relatively low energy are confirmed in both approaches. We employ the survival probability instead of the terminal energy to assess whether a neutrino with a given energy is observable or not in the OPERA experiment. Moreover, using our general results we perform systematical analyses on the constraints arising from the Super-Kamiokande and IceCube experiments.

  13. Seismic Velocity Estimation from Time Migration Velocities M. K. Cameron, S. B. Fomel, J. A. Sethian

    E-Print Network [OSTI]

    Sethian, James A.

    Seismic Velocity Estimation from Time Migration Velocities M. K. Cameron, S. B. Fomel, J. A the problem of estimating seismic velocities inside the earth which is necessary for obtaining seismic images in regular Cartesian coordinates. We derive a relation between the true seismic velocities and the routinely

  14. Impact of Phase Transitions on P Wave Velocities

    SciTech Connect (OSTI)

    D Weidner; L Li

    2011-12-31T23:59:59.000Z

    In regions where a high pressure phase is in equilibrium with a low pressure phase, the bulk modulus defined by the P-V relationship is greatly reduced. Here we evaluate the effect of such transitions on the P wave velocity. A model, where cation diffusion is the rate limiting factor, is used to project laboratory data to the conditions of a seismic wave propagating in the two-phase region. We demonstrate that for the minimum expected effect there is a significant reduction of the seismic velocity, as large as 10% over a narrow depth range.

  15. Wave VelocityWave Velocity Diff t f ti l l itDifferent from particle velocity

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    Wave VelocityWave Velocity v=/T =f Diff t f ti l l itDifferent from particle velocity Depends on the medium in which the wave travelsDepends on the medium in which the wave travels stringaonvelocity F v of Waves11-8. Types of Waves Transverse wave Longitudinal wave Liu UCD Phy1B 2014 37 #12;Sound Wave

  16. Instructions for use Short-term Glacier Velocity Changes at West Kunlun

    E-Print Network [OSTI]

    Tsunogai, Urumu

    to global warming could further accelerate glacier15 flow and potentially lead to significant lossInstructions for use #12;Short-term Glacier Velocity Changes at West Kunlun Shan, Northwest Tibet. Abstract Seasonal glacier velocity changes across the High Arctic, including the Green- land Ice Sheet

  17. Precision reconstruction of the dark matter-neutrino relative velocity from N-body simulations

    E-Print Network [OSTI]

    Inman, Derek; Pen, Ue-Li; Farchi, Alban; Yu, Hao-Ran; Harnois-Deraps, Joachim

    2015-01-01T23:59:59.000Z

    Discovering the mass of neutrinos is a principle goal in high energy physics and cosmology. In addition to cosmological measurements based on two-point statistics, the neutrino mass can also be estimated by observations of neutrino wakes resulting from the relative motion between dark matter and neutrinos. Such a detection relies on an accurate reconstruction of the dark matter-neutrino relative velocity which is affected by non-linear structure growth and galaxy bias. We investigate our ability to reconstruct this relative velocity using large N-body simulations where we evolve neutrinos as distinct particles alongside the dark matter. We find that the dark matter velocity power spectrum is overpredicted by linear theory whereas the neutrino velocity power spectrum is underpredicted. The magnitude of the relative velocity observed in the simulations is found to be lower than what is predicted in linear theory. Since neither the dark matter nor the neutrino velocity fields are directly observable from galaxy ...

  18. Minimum and terminal velocities in projectile motion

    E-Print Network [OSTI]

    E. N. Miranda; S. Nikolskaya; R. Riba

    2012-08-13T23:59:59.000Z

    The motion of a projectile with horizontal initial velocity V0, moving under the action of the gravitational field and a drag force is studied analytically. As it is well known, the projectile reaches a terminal velocity Vterm. There is a curious result concerning the minimum speed Vmin; it turns out that the minimum velocity is lower than the terminal one if V0 > Vterm and is lower than the initial one if V0 < Vterm. These results show that the velocity is not a monotonous function. If the initial speed is not horizontal, there is an angle range where the velocity shows the same behavior mentioned previously. Out of that range, the volocity is a monotonous function. These results come out from numerical simulations.

  19. Cosmological Constraints from Galaxy Cluster Velocity Statistics

    E-Print Network [OSTI]

    Suman Bhattacharya; Arthur Kosowsky

    2007-04-20T23:59:59.000Z

    Future microwave sky surveys will have the sensitivity to detect the kinematic Sunyaev-Zeldovich signal from moving galaxy clusters, thus providing a direct measurement of their line-of-sight peculiar velocity. We show that cluster peculiar velocity statistics applied to foreseeable surveys will put significant constraints on fundamental cosmological parameters. We consider three statistical quantities that can be constructed from a cluster peculiar velocity catalog: the probability density function, the mean pairwise streaming velocity, and the pairwise velocity dispersion. These quantities are applied to an envisioned data set which measures line-of-sight cluster velocities with normal errors of 100 km/s for all clusters with masses larger than $10^{14}$ solar masses over a sky area of up to 5000 square degrees. A simple Fisher matrix analysis of this survey shows that the normalization of the matter power spectrum and the dark energy equation of state can be constrained to better than 10 percent, and the Hubble constant and the primordial power spectrum index can be constrained to a few percent, independent of any other cosmological observations. We also find that the current constraint on the power spectrum normalization can be improved by more than a factor of two using data from a 400 square degree survey and WMAP third-year priors. We also show how the constraints on cosmological parameters changes if cluster velocities are measured with normal errors of 300 km/s.

  20. Estimating seismic velocities at ultrasonic frequencies in partially saturated rocks

    SciTech Connect (OSTI)

    Mavko, G.; Nolen-Hoeksema, R. (Stanford Univ., CA (United States). Dept. of Geophysics)

    1994-02-01T23:59:59.000Z

    Seismic velocities in rocks at ultrasonic frequencies depend not only on the degree of saturation but also on the distribution of the fluid phase at various scales within the pore space. Two scales of saturation heterogeneity are important: (1) saturation differences between thin compliant pores and larger stiffer pores, and (2) differences between saturated patches and undersaturated patches at a scale much larger than any pore. The authors propose a formalism for predicting the range of velocities in partially saturated rocks that avoids assuming idealized pore shapes by using measured dry rock velocity versus pressure and dry rock porosity versus pressure. The pressure dependence contains all of the necessary information about the distribution of pore compliance for estimating effects of saturation at the finest scales where small amounts of fluid in the thinnest, most compliant parts of the pore space stiffen the rock in both compression and shear (increasing both P- and S-wave velocities) in approximately the same way that confining pressure stiffens the rock by closing the compliant pores. Large-scale saturation patches tend to increase only the high-frequency bulk modulus by amounts roughly proportional to the saturation. The pore-scale effects will be most important at laboratory and logging frequencies when pore-scale pore pressure gradients are unrelaxed. The patchy-saturation effects can persist even at seismic field frequencies if the patch sizes are sufficiently large and the diffusivities are sufficiently low for the larger-scale pressure gradients to be unrelaxed.

  1. The stellar wind velocity field of HD 77581

    E-Print Network [OSTI]

    Manousakis, A

    2015-01-01T23:59:59.000Z

    The early acceleration of stellar winds in massive stars is poorly constrained. The scattering of hard X-ray photons emitted by the pulsar in the high-mass X-ray binary Vela X-1 can be used to probe the stellar wind velocity and density profile close to the surface of its supergiant companion HD 77581. We built a high signal-to-noise and high resolution hard X-ray lightcurve of Vela X-1 measured by Swift/BAT over 300 orbital periods of the system and compared it with the predictions of a grid of hydrodynamic simulations. We obtain a very good agreement between observations and simulations for a narrow set of parameters, implying that the wind velocity close to the stellar surface is twice larger than usually assumed with the standard beta law. Locally a velocity gradient of $\\beta\\sim0.5$ is favoured. Even if still incomplete, hydrodynamic simulations are successfully reproducing several observational properties of Vela X-1.

  2. Measuring Stellar Radial Velocities with a Dispersed Fixed-Delay Interferometer

    E-Print Network [OSTI]

    Suvrath Mahadevan; Julian van Eyken; Jian Ge; Curtis DeWitt; Scott W. Fleming; Roger Cohen; Justin Crepp; Andrew Vanden Heuvel

    2008-01-25T23:59:59.000Z

    We demonstrate the ability to measure precise stellar barycentric radial velocities with the dispersed fixed-delay interferometer technique using the Exoplanet Tracker (ET), an instrument primarily designed for precision differential Doppler velocity measurements using this technique. Our barycentric radial velocities, derived from observations taken at the KPNO 2.1 meter telescope, differ from those of Nidever et al. by 0.047 km/s (rms) when simultaneous iodine calibration is used, and by 0.120 km/s (rms) without simultaneous iodine calibration. Our results effectively show that a Michelson interferometer coupled to a spectrograph allows precise measurements of barycentric radial velocities even at a modest spectral resolution of R ~ 5100. A multi-object version of the ET instrument capable of observing ~500 stars per night is being used at the Sloan 2.5 m telescope at Apache Point Observatory for the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS), a wide-field radial velocity survey for extrasolar planets around TYCHO-2 stars in the magnitude range 7.6velocities, this survey will also yield precise barycentric radial velocities for many thousands of stars using the data analysis techniques reported here. Such a large kinematic survey at high velocity precision will be useful in identifying the signature of accretion events in the Milky Way and understanding local stellar kinematics in addition to discovering exoplanets, brown dwarfs and spectroscopic binaries.

  3. Undersampling to accelerate time-resolved MRI velocity measurement of carotid blood flow 

    E-Print Network [OSTI]

    Tao, Yuehui

    2009-01-01T23:59:59.000Z

    Time-resolved velocity information of carotid blood flow can be used to estimate haemodynamic conditions associated with carotid artery disease leading to stroke. MRI provides high-resolution measurement of such information ...

  4. Modeling velocity dispersion In Gypsy site, Oklahoma

    E-Print Network [OSTI]

    Alsaadan, Sami Ibrahim

    2010-01-01T23:59:59.000Z

    Discrepancies in interval velocities estimated from vertical well measurements made with different source central frequencies at Gypsy site could be primarily explained in terms of intrinsic attenuation. Four intervals ...

  5. Acoustic measurement of potato cannon velocity

    E-Print Network [OSTI]

    Courtney, M; Courtney, Amy; Courtney, Michael

    2006-01-01T23:59:59.000Z

    This article describes measurement of potato cannon velocity with a digitized microphone signal. A microphone is attached to the potato cannon muzzle and a potato is fired at an aluminum target about 10 m away. The potato's flight time can be determined from the acoustic waveform by subtracting the time in the barrel and time for sound to return from the target. The potato velocity is simply the flight distance divided by the flight time.

  6. Extracting Fish and Water Velocity from Doppler Profiler Data

    E-Print Network [OSTI]

    deYoung, Brad

    Extracting Fish and Water Velocity from Doppler Profiler Data ĺ Ð 1 ¸ Ö Ò ×¹ Ò ÝÖ¹Ê Ò 2 1 processing algo- rithms normally used to extract water velocity. We present an alternative method for velocity homogeneity precludes the extraction of fish velocities. Water velocities can sometimes still

  7. Velocity dependence of friction of confined polymers

    E-Print Network [OSTI]

    I. M. Sivebaek; V. N. Samoilov; B. N. J. Persson

    2009-11-18T23:59:59.000Z

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: (a) polymer sliding against a hard substrate, and (b) polymer sliding on polymer. We discuss the velocity dependence of the frictional shear stress for both cases. In our simulations, the polymer films are very thin (approx. 3 nm), and the solid walls are connected to a thermostat at a short distance from the polymer slab. Under these circumstances we find that frictional heating effects are not important, and the effective temperature in the polymer film is always close to the thermostat temperature. In the first setup (a), for hydrocarbons with molecular lengths from 60 to 1400 carbon atoms, the shear stresses are nearly independent of molecular length, but for the shortest hydrocarbon C20H42 the frictional shear stress is lower. In all cases the frictional shear stress increases monotonically with the sliding velocity. For polymer sliding on polymer [case (b)] the friction is much larger, and the velocity dependence is more complex. For hydrocarbons with molecular lengths from 60 to 140 C-atoms, the number of monolayers of lubricant increases (abruptly) with increasing sliding velocity (from 6 to 7 layers), leading to a decrease of the friction. Before and after the layering transition, the frictional shear stresses are nearly proportional to the logarithm of sliding velocity. For the longest hydrocarbon (1400 C-atoms) the friction shows no dependence on the sliding velocity, and for the shortest hydrocarbon (20 C-atoms) the frictional shear stress increases nearly linearly with the sliding velocity.

  8. GALAXY CLUSTER BULK FLOWS AND COLLISION VELOCITIES IN QUMOND

    SciTech Connect (OSTI)

    Katz, Harley; McGaugh, Stacy; Teuben, Peter [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Angus, G. W., E-mail: hkatz@astro.umd.edu, E-mail: stacy.mcgaugh@case.edu, E-mail: teuben@astro.umd.edu, E-mail: angus.gz@gmail.com [Astrophysics, Cosmology and Gravity Centre, University of Cape Town, Private Bag X3, Rondebosch 7700 (South Africa)

    2013-07-20T23:59:59.000Z

    We examine the formation of clusters of galaxies in numerical simulations of a QUMOND cosmogony with massive sterile neutrinos. Clusters formed in these exploratory simulations develop higher velocities than those found in {Lambda}CDM simulations. The bulk motions of clusters attain {approx}1000 km s{sup -1} by low redshift, comparable to observations whereas {Lambda}CDM simulated clusters tend to fall short. Similarly, high pairwise velocities are common in cluster-cluster collisions like the Bullet Cluster. There is also a propensity for the most massive clusters to be larger in QUMOND and to appear earlier than in {Lambda}CDM, potentially providing an explanation for ''pink elephants'' like El Gordo. However, it is not obvious that the cluster mass function can be recovered.

  9. Relation between plasma plume density and gas flow velocity in atmospheric pressure plasma

    SciTech Connect (OSTI)

    Yambe, Kiyoyuki; Taka, Shogo; Ogura, Kazuo [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)] [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan)

    2014-04-15T23:59:59.000Z

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and copper foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. To study the properties of the plasma plume, the plasma plume current is estimated from the difference in currents on the circuit, and the drift velocity is measured using a photodetector. The relation of the plasma plume density n{sub plu}, which is estimated from the current and the drift velocity, and the gas flow velocity v{sub gas} is examined. It is found that the dependence of the density on the gas flow velocity has relations of n{sub plu} ? log(v{sub gas}). However, the plasma plume density in the laminar flow is higher than that in the turbulent flow. Consequently, in the laminar flow, the density increases with increasing the gas flow velocity.

  10. Experimental High Velocity Acid Jetting in Limestone Carbonates

    E-Print Network [OSTI]

    Holland, Christopher

    2014-04-30T23:59:59.000Z

    spacers have an OD of 4” and an ID of 3.5”. One spacer ring has a 2” length and the other has a 0.25” length for a total Lsp of 2.25”. Therefore, from Eq. 2.13: (2.14) The outlet holder, Fig. 2.4D secures the outlet side...…………………………………………………………… 2.2 Pulse Pump……………………………………………………………… 2.3 Core Holder…………………………………………………………….. 2.4 Hydraulic Pump………………………………………………………… 2.5 Backpressure Regulator…………………………………………………. 2.6 Data Acquisition………………………………………………………… 2.7 Permeability Measuring...

  11. air velocity effects: Topics by E-print Network

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

    transfer velocities. A moving tropical cyclone is an intense source of surface wind stress Chu, Peter C. 4 The exit velocity of a compressed air cannon CERN Preprints...

  12. On the definition of velocity in doubly special relativity theories

    E-Print Network [OSTI]

    Piotr Kosinski; Pawel Maslanka

    2002-11-13T23:59:59.000Z

    We discuss the definition of particle velocity in doubly relativity theories. The general formula relating velocity and four-momentum of particle is given.

  13. Antarctica: measuring glacier velocity from satellite images

    SciTech Connect (OSTI)

    Lucchitta, B.K.; Ferguson, H.M.

    1986-11-28T23:59:59.000Z

    Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

  14. Lagrangian reconstruction of cosmic velocity fields

    E-Print Network [OSTI]

    G. Lavaux

    2008-01-28T23:59:59.000Z

    We discuss a Lagrangian reconstruction method of the velocity field from galaxy redshift catalog that takes its root in the Euler equation. This results in a ``functional'' of the velocity field which must be minimized. This is helped by an algorithm solving the minimization of cost-flow problems. The results obtained by applying this method to cosmological problems are shown and boundary effects happening in real observational cases are then discussed. Finally, a statistical model of the errors made by the reconstruction method is proposed.

  15. Threshold velocity for environmentally-assisted cracking in low alloy steels

    SciTech Connect (OSTI)

    Wire, G.L.; Kandra, J.T.

    1997-04-01T23:59:59.000Z

    Environmentally Assisted Cracking (EAC) in low alloy steels is generally believed to be activated by dissolution of MnS inclusions at the crack tip in high temperature LWR environments. EAC is the increase of fatigue crack growth rate of up to 40 to 100 times the rate in air that occurs in high temperature LWR environments. A steady state theory developed by Combrade, suggested that EAC will initiate only above a critical crack velocity and cease below this same velocity. A range of about twenty in critical crack tip velocities was invoked by Combrade, et al., to describe data available at that time. This range was attributed to exposure of additional sulfides above and below the crack plane. However, direct measurements of exposed sulfide densities on cracked specimens were performed herein and the results rule out significant additional sulfide exposure as a plausible explanation. Alternatively, it is proposed herein that localized EAC starting at large sulfide clusters reduces the calculated threshold velocity from the value predicted for a uniform distribution of sulfides. Calculations are compared with experimental results where the threshold velocity has been measured, and the predicted wide range of threshold values for steels of similar sulfur content but varying sulfide morphology is observed. The threshold velocity decreases with the increasing maximum sulfide particle size, qualitatively consistent with the theory. The calculation provides a basis for a conservative minimum velocity threshold tied directly to the steel sulfur level, in cases where no details of sulfide distribution are known.

  16. Neutron Star Population Dynamics.II: 3D Space Velocities of Young Pulsars

    E-Print Network [OSTI]

    J. M. Cordes; David F. Chernoff

    1997-07-28T23:59:59.000Z

    We use astrometric, distance and spindown data on pulsars to: (1) estimate three-dimensional velocity components, birth distances from the galactic plane, and ages of individual objects; (2) determine the distribution of space velocities and the scale height of pulsar progenitors; (3) test spindown laws for pulsars; (4) test for correlations between space velocities and other pulsar parameters; and (5) place empirical requirements on mechanisms than can produce high velocity neutron stars. Our approach incorporates measurement errors, uncertainties in distances, deceleration in the Galactic potential, and differential galactic rotation. We find that the scale height of the progenitors is approximately 0.13 kpc, that the 3D velocities are distributed in two components with characteristic speeds of 175(+20,-30) km/s and 700(+200,-150) km/s representing 83% and 17% of the population respectively. These results are insensitive to the explicit relation of chronological and spindown ages. We infer that the most probable chronological ages are typically smaller than conventional spindown ages by factors as large as two. We assess mechanisms for producing high-velocity neutron stars in view of the derived velocity distribution function.

  17. VELOCITY AND MAGNETIC FIELD DISTRIBUTION IN A FORMING PENUMBRA

    SciTech Connect (OSTI)

    Romano, P.; Guglielmino, S. L. [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95125 Catania (Italy); Frasca, D.; Zuccarello, F. [Dipartimento di Fisica e Astronomia-Sezione Astrofisica, Universita di Catania, Via S. Sofia 78, I-95125 Catania (Italy); Ermolli, I. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone (Italy); Tritschler, A.; Reardon, K. P., E-mail: prom@oact.inaf.it [National Solar Observatory/Sacramento Peak, P.O. Box 62, Sunspot, NM 88349-0062 (United States)

    2013-07-01T23:59:59.000Z

    We present results from the analysis of high-resolution spectropolarimetric and spectroscopic observations of the solar photosphere and chromosphere, obtained shortly before the formation of a penumbra in one of the leading polarity sunspots of NOAA active region 11490. The observations were performed at the Dunn Solar Telescope of the National Solar Observatory on 2012 May 28, using the Interferometric Bidimensional Spectrometer. The data set is comprised of a 1 hr time sequence of measurements in the Fe I 617.3 nm and Fe I 630.25 nm lines (full Stokes polarimetry) and in the Ca II 854.2 nm line (Stokes I only). We perform an inversion of the Fe I 630.25 nm Stokes profiles to derive magnetic field parameters and the line-of-sight (LOS) velocity at the photospheric level. We characterize chromospheric LOS velocities by the Doppler shift of the centroid of the Ca II 854.2 nm line. We find that, before the formation of the penumbra, an annular zone of 3''-5'' width is visible around the sunspot. In the photosphere, we find that this zone is characterized by an uncombed structure of the magnetic field although no visible penumbra has formed yet. We also find that the chromospheric LOS velocity field shows several elongated structures characterized by downflow and upflow motions in the inner and outer parts of the annular zone, respectively.

  18. Terminal velocities of luminous, early-type SMC stars

    E-Print Network [OSTI]

    C. J. Evans; D. J. Lennon; C. Trundle; S. R. Heap; D. J. Lindler

    2004-03-12T23:59:59.000Z

    Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultraviolet Explorer telescope, terminal velocities are obtained for a further five B-type supergiants. We discuss the metallicity dependence of stellar terminal velocities, finding no evidence for a significant scaling between Galactic and SMC metallicities for Teff < 30,000 K, consistent with the predictions of radiation driven wind theory for supergiant stars. A comparison of the $v_\\infty / v_{esc}$ ratio between the SMC and Galactic samples, while consistent with the above statement, emphasizes that the uncertainties in the distances to galactic O-stars are a serious obstacle to a detailed comparison with theory. For the SMC sample there is considerable scatter in this ratio at a given effective temperature, perhaps indicative of uncertainties in stellar masses.

  19. PERFORMANCE EFFECTS OF AIR VELOCITY PROFILES IN

    E-Print Network [OSTI]

    PERFORMANCE EFFECTS OF AIR VELOCITY PROFILES IN A RESIDENTIAL HEAT PUMP By NATHAN ANDREW WEBER PROFILES IN A RESIDENTIAL HEAT PUMP Thesis Approved: _______________________________________ Thesis Advisor the air speed transducer mount and the Plexiglas model of the heat pump. Ipseng Iu and myself worked side

  20. A MAGNETIC CALIBRATION OF PHOTOSPHERIC DOPPLER VELOCITIES

    SciTech Connect (OSTI)

    Welsch, Brian T.; Fisher, George H. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Sun, Xudong [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2013-03-10T23:59:59.000Z

    The zero point of measured photospheric Doppler shifts is uncertain for at least two reasons: instrumental variations (from, e.g., thermal drifts); and the convective blueshift, a known correlation between intensity and upflows. Accurate knowledge of the zero point is, however, useful for (1) improving estimates of the Poynting flux of magnetic energy across the photosphere, and (2) constraining processes underlying flux cancellation, the mutual apparent loss of magnetic flux in closely spaced, opposite-polarity magnetogram features. We present a method to absolutely calibrate line-of-sight (LOS) velocities in solar active regions (ARs) near disk center using three successive vector magnetograms and one Dopplergram coincident with the central magnetogram. It exploits the fact that Doppler shifts measured along polarity inversion lines (PILs) of the LOS magnetic field determine one component of the velocity perpendicular to the magnetic field, and optimizes consistency between changes in LOS flux near PILs and the transport of transverse magnetic flux by LOS velocities, assuming that ideal electric fields govern the magnetic evolution. Previous calibrations fitted the center-to-limb variation of Doppler velocities, but this approach cannot, by itself, account for residual convective shifts at the limb. We apply our method to vector magnetograms of AR 11158, observed by the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory, and find clear evidence of offsets in the Doppler zero point in the range of 50-550 m s{sup -1}. In addition, we note that a simpler calibration can be determined from an LOS magnetogram and Dopplergram pair from the median Doppler velocity among all near-disk-center PIL pixels. We briefly discuss shortcomings in our initial implementation, and suggest ways to address these. In addition, as a step in our data reduction, we discuss the use of temporal continuity in the transverse magnetic field direction to correct apparently spurious fluctuations in resolution of the 180 Degree-Sign ambiguity.

  1. 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

    SciTech Connect (OSTI)

    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

    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.

  2. Reconstructing the WIMP Velocity Distribution from Direct Dark Matter Detection Data with a Non-negligible Threshold Energy

    E-Print Network [OSTI]

    Shan, Chung-Lin

    2015-01-01T23:59:59.000Z

    In this paper, we investigate the modification of our expressions developed for the model-independent data analysis procedure of the reconstruction of the (time-averaged) one-dimensional velocity distribution of Galactic Weakly Interacting Massive Particles (WIMPs) with a non-negligible experimental threshold energy. Our numerical simulations show that, for a minimal reconstructable velocity of as high as O(200) km/s, our model-independent modification of the estimator for the normalization constant could provide precise reconstructed velocity distribution points to match the true WIMP velocity distribution with a <~ 10% bias.

  3. Relativistic equilibrium velocity distribution, nuclear fusion reaction rate and the solar neutrino problem

    E-Print Network [OSTI]

    Jian-Miin Liu

    2003-07-07T23:59:59.000Z

    In solar interior, it is the equilibrium velocity distribution of few high-energy protons and nuclei that participates in determining nuclear fusion reaction rates. So, it is inappropriate to use the Maxwellian velocity distribution to calculate the rates of solar nuclear fusion reactions. We have to use the relativistic equilibrium velocity distribution for the purpose. The nuclear fusion reaction rate based on the relativistic equilibrium velocity distribution has a reduction factor with respect to that based on the Maxwellian distribution. The reduction factor depends on the temperature, reduced mass and atomic numbers of the studied nuclear fusion reactions, in other words, it varies with the sort of neutrinos. Substituting the relativistic equilibrium velocity distribution for the Maxwellian distribution is not important for the calculation of solar sound speeds. The relativistic equilibrium velocity distribution, if adopted in standard solar models, will lower solar neutrino fluxes and change solar neutrino energy spectra but maintain solar sound speeds. This velocity distribution is possibly a solution to the solar neutrino problem.

  4. Comment on "Pulsar Velocities and Neutrino Oscillations"

    E-Print Network [OSTI]

    Y. -Z. Qian

    1997-05-08T23:59:59.000Z

    In a recent Letter, Kusenko and Segre proposed a new mechanism to explain the observed proper motions of pulsars. Their mechanism was based on the asymmetric neutrino emission induced by neutrino oscillations in the protoneutron star magnetic field. In this note I point out that their estimate of the asymmetry in the neutrino emission is incorrect. A proper calculation shows that their mechanism at least requires a magnetic field of 10**16 G in order to produce the observed average pulsar velocity.

  5. On Pulsar Velocities from Neutrino Oscillations

    E-Print Network [OSTI]

    Michael Birkel; Ramon Toldra

    1997-06-11T23:59:59.000Z

    It has been recently suggested that magnetically affected neutrino oscillations inside a cooling protoneutron star, created in a supernova explosion, could explain the large proper motion of pulsars. We investigate whether this hypothesis is in agreement with the observed properties of pulsars and find that present data disfavor the suggested mechanism. The relevance of our results for other models proposed to understand the origin of pulsar velocities is also discussed.

  6. Slow group velocity and Cherenkov radiation

    E-Print Network [OSTI]

    I. Carusotto; M. Artoni; G. C. La Rocca; F. Bassani

    2001-03-12T23:59:59.000Z

    We theoretically study the effect of ultraslow group velocities on the emission of Vavilov-Cherenkov radiation in a coherently driven medium. We show that in this case the aperture of the group cone on which the intensity of the radiation peaks is much smaller than that of the usual wave cone associated with the Cherenkov coherence condition. We show that such a singular behaviour may be observed in a coherently driven ultracold atomic gas.

  7. Irregular wave induced velocities in shallow water

    E-Print Network [OSTI]

    Sultan, Nels John

    1991-01-01T23:59:59.000Z

    probabil- ity density function. This thesis applies this expanded distribution to fluid particle velocities instead of wave elevations. Ochi (1982) presents a review of recent ad- vances in the stochastic analysis of random seas. He notes that the first..., (Longuet-Higgins 1963), that purely linear waves will have a Gaussian distribu- tion. Therefore, any deviation from a Gaussian distribution must be attributed to wave nonlinearities. Ochi (1982) discusses a series of experiments by Honda and Mitsuyasu...

  8. Temperature dependent sound velocity in hydrodynamic equations for relativistic heavy-ion collisions

    E-Print Network [OSTI]

    Mikolaj Chojnacki

    2007-09-11T23:59:59.000Z

    We analyze the effects of different forms of the sound-velocity function cs(T) on the hydrodynamic evolution of matter formed in the central region of relativistic heavy-ion collisions. At high temperatures (above the critical temperature Tc) the sound velocity is calculated from the recent lattice simulations of QCD, while in the low temperature region it is obtained from the hadron gas model. In the intermediate region we use different interpolations characterized by the values of the sound velocity at the local maximum (at T = 0.4 Tc) and local minimum (at T = Tc). In all considered cases the temperature dependent sound velocity functions yield the entropy density, which is consistent with the lattice QCD simulations at high temperature. Our calculations show that the presence of a distinct minimum of the sound velocity leads to a very long (about 20 fm/c) evolution time of the system, which is not compatible with the recent estimates based on the HBT interferometry. Hence, we conclude that the hydrodynamic description is favored in the case where the cross-over phase transition renders the smooth sound velocity function with a possible shallow minimum at Tc.

  9. Constraining Spiral Structure Parameters through Galactic Pencil-beam and Large-scale Radial Velocity Surveys

    E-Print Network [OSTI]

    I. Minchev; A. Quillen

    2007-10-26T23:59:59.000Z

    We investigate the effect of spiral structure on the Galactic disk as viewed by pencil beams centered on the Sun, relevant to upcoming surveys such as ARGOS, SEGUE, and GAIA. We create synthetic Galactic maps which we call Pencil Beam Maps (PBMs) of the following observables: line-of-sight velocities, the corresponding velocity dispersion, and the stellar number density that are functions of distance from the observer. We show that such maps can be used to infer spiral structure parameters, such as pattern speed, solar phase angle, and number of arms. The mean line-of-sight velocity and velocity dispersion are affected by up to ~35 km/s which is well within the detectable limit for forthcoming radial velocity surveys. One can measure the pattern speed by searching for imprints of resonances. In the case of a two-armed spiral structure it can be inferred from the radius of a high velocity dispersion ring situated at the 2:1 ILR. This information, however, must be combined with information related to the velocities and stellar number density in order to distinguish from a four-armed structure. If the pattern speed is such that the 2:1 ILR is hidden inside the Galactic bulge the 2:1 OLR will be present in the outer Galaxy and thus can equivalently be used to estimate the pattern speed. Once the pattern speed is known the solar angle can be estimated from the line-of-sight velocities and the number density PBMs. Forthcoming radial velocity surveys are likely to provide powerful constraints of the structure of the Milky Way disk.

  10. The nuclear fusion reaction rate based on relativistic equilibrium velocity distribution

    E-Print Network [OSTI]

    Jian-Miin Liu

    2002-10-20T23:59:59.000Z

    The Coulomb barrier is in general much higher than thermal energy. Nuclear fusion reactions occur only among few protons and nuclei with higher relative energies than Coulomb barrier. It is the equilibrium velocity distribution of these high-energy protons and nuclei that participates in determining the rate of nuclear fusion reactions. In the circumstance it is inappropriate to use the Maxwellian velocity distribution for calculating the nuclear fusion reaction rate. We use the relativistic equilibrium velocity distribution for this purpose. The rate based on the relativistic equilibrium velocity distribution has a reduction factor with respect to that based on the Maxwellian distribution, which factor depends on the temperature, reduced mass and atomic numbers of the studied nuclear fusion reactions. This signifies much to the solar neutrino problem.

  11. On the velocity-strengthening behavior of dry friction

    E-Print Network [OSTI]

    Bar-Sinai, Yohai; Brener, Efim A; Bouchbinder, Eran

    2013-01-01T23:59:59.000Z

    The onset of frictional instabilities, e.g. earthquakes nucleation, is intimately related to velocity-weakening friction, in which the frictional resistance of interfaces decreases with increasing slip velocity. While this frictional response has been studied extensively, much less attention has been given to steady-state velocity-strengthening friction, in spite of its importance for various aspects of frictional phenomena such as the propagation speed of interfacial rupture fronts and the amount of stored energy released by them. In this note we suggest that a crossover from steady-state velocity-weakening friction at small slip velocities to steady-state velocity-strengthening friction at higher velocities might be a generic feature of dry friction. We further argue that while thermally activated rheology naturally gives rise to logarithmic steady-state velocity-strengthening friction, a crossover to stronger-than-logarithmic strengthening might take place at higher slip velocities, possibly accompanied by...

  12. Unexplored Aspect of Velocity of light

    E-Print Network [OSTI]

    Abhijit Biswas; Krishnan RS Mani

    2008-05-13T23:59:59.000Z

    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.

  13. Velocity-selected molecular pulses produced by an electric guide

    SciTech Connect (OSTI)

    Sommer, C.; Motsch, M.; Chervenkov, S.; Buuren, L. D. van; Zeppenfeld, M.; Pinkse, P. W. H.; Rempe, G. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching (Germany)

    2010-07-15T23:59:59.000Z

    Electrostatic velocity filtering is a technique for the production of continuous guided beams of slow polar molecules from a thermal gas. We extended this technique to produce pulses of slow molecules with a narrow velocity distribution around a tunable velocity. The pulses are generated by sequentially switching the voltages on adjacent segments of an electric quadrupole guide synchronously with the molecules propagating at the desired velocity. This technique is demonstrated for deuterated ammonia (ND{sub 3}), delivering pulses with a velocity in the range of 20-100 m/s and a relative velocity spread of (16{+-}2)% at full width at half maximum. At velocities around 60 m/s, the pulses contain up to 10{sup 6} molecules each. The data are well reproduced by Monte Carlo simulations, which provide useful insight into the mechanisms of velocity selection.

  14. Orthogonal-Phase-Velocity Propagation of Electromagnetic Plane Waves

    E-Print Network [OSTI]

    Tom G. Mackay; Akhlesh Lakhtakia

    2005-11-30T23:59:59.000Z

    In an isotropic, homogeneous, nondissipative, dielectric-magnetic medium that is simply moving with respect to an inertial reference frame, planewave solutions of the Maxwell curl postulates can be such that the phase velocity and the time-averaged Poynting vector are mutually orthogonal. Orthogonal-phase-velocity propagation thus adds to the conventional positive-phase-velocity propagation and the recently discovered negative-phase-velocity propagation that is associated with the phenomenon of negative refraction.

  15. Experimental investigation of velocity biasing in laser Doppler anemometry

    E-Print Network [OSTI]

    Wiedner, Brian Gregory

    1988-01-01T23:59:59.000Z

    Tech University; Chair of Advisory Commettee: Dr. Gerald L. Morrison The effects of several velocity bias reduction schemes were invest- igated using a 3-D laser Doppler anemometer and counter type (burst) signal processors. Amongst these schemes... of Sample Size on Effects of Sample Size on Effects of Sample Size on Effects of Sample Size on Velocity and Reynolds Stresses Axial Mean Velocity Radial Mean Velocity Axial Turbulence Intensity Radial Turbulence Intensity Axial/Radial Correlation...

  16. Velocity and attenuation in partially molten rocks

    SciTech Connect (OSTI)

    Mavko, G.M.

    1980-10-10T23:59:59.000Z

    Interpretation of seismic velocity and attenuation in partially molten rocks has been limited, with few exceptions, to models that assume the melt to be distributed either as spheres or as thin films. However, other melt phase geometries, such as interconnected tubes along grain edges, might equally well account for seismic observations if there is a much larger fraction of melt. Seismic velocity and attenuation are estimated in rocks in which the melt phase has the tube geometry, and the results are compared with results expected for the more familiar film model under similar conditions. For a given melt fraction, tubes are found to give moduli intermediate between moduli for rigid spherical inclusions and compliant films. For example, in polycrystalline olivine at 20 kbar the model predicts a decrease in V/sub s/ of 10% and a decrease in V/sub p/ of 5% at 0.05 melt fraction, without considering inelastic relaxation. Shear attenuation appears to be dominated by viscous flow of melt between the tubes and/or films. For olivine the tube model predicts the increment of relaxation due to melt, ..delta mu../..mu.., to be 0.01 at 0.05 melt fraction. Relaxation of the bulk modulus is dominated by flow between melt pockets of different shape, heat flow, and solid-melt phase change. If melt is present, considerable bulk attenuation is expected, although the relaxation may be observable only at long periods, outside the seismic body wave band.

  17. Seismic Velocity Estimation from Time Migration Maria Kourkina Cameron

    E-Print Network [OSTI]

    Cameron, Maria Kourkina

    Seismic Velocity Estimation from Time Migration by Maria Kourkina Cameron Diplom (Moscow Institute Dung-Hai Lee Spring 2007 #12;Seismic Velocity Estimation from Time Migration Copyright c 2007 by Maria Kourkina Cameron #12;Abstract Seismic Velocity Estimation from Time Migration by Maria Kourkina Cameron

  18. CONVERGENT FLOWS AND LOW-VELOCITY SHOCKS IN DR21(OH)

    SciTech Connect (OSTI)

    Csengeri, T. [Max Planck Institute for Radioastronomy, Auf dem Huegel 69, 53121 Bonn (Germany); Bontemps, S. [OASU/LAB-UMR5804, CNRS, Universite Bordeaux 1, 33270 Floirac (France); Schneider, N.; Motte, F. [Laboratoire AIM Paris Saclay, CEA-INSU/CNRS-Universite Paris Diderot, IRFU/SAp CEA-Saclay, 91191 Gif-sur-Yvette (France); Gueth, F. [IRAM, 300 rue de la piscine, 38406, Saint Martin d'Heres (France); Hora, J. L., E-mail: ctimea@mpifr-bonn.mpg.de [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-65, Cambridge, MA 02138 (United States)

    2011-10-10T23:59:59.000Z

    DR21(OH) is a pc-scale massive, {approx}7000 M{sub sun} clump hosting three massive dense cores (MDCs) at an early stage of their evolution. We present a high angular resolution mosaic, covering {approx}70'' x 100'', with the IRAM Plateau de Bure Interferometer at 3 mm to trace the dust continuum emission and the N{sub 2}H{sup +} (J = 1-0) and CH{sub 3}CN (J = 5-4) molecular emission. The cold, dense gas traced by the compact emission in N{sub 2}H{sup +} is associated with the three MDCs and shows several velocity components toward each MDC. These velocity components reveal local shears in the velocity fields which are best interpreted as convergent flows. Moreover, we report the detection of weak extended emission from CH{sub 3}CN at the position of the N{sub 2}H{sup +} velocity shears. We propose that this extended CH{sub 3}CN emission is tracing warm gas associated with the low-velocity shocks expected at the location of convergence of the flows where velocity shears are observed. This is the first detection of low-velocity shocks associated with small (subparsec) scale convergent flows which are proposed to be at the origin of the densest structures and of the formation of (high-mass) stars. In addition, we propose that MDCs may be active sites of star formation for more than a crossing time as they continuously receive material from larger scale flows as suggested by the global picture of dynamical, gravity-driven evolution of massive clumps which is favored by the present observations.

  19. Force-velocity relations for multiple molecular motor transportation

    E-Print Network [OSTI]

    Wang, Ziqing

    2009-01-01T23:59:59.000Z

    A transition rate model of cargo transportation by N effective 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 experimental observations.

  20. Force-velocity relations for multiple-molecular-motor transport

    E-Print Network [OSTI]

    Ziqing Wang; Ming Li

    2009-10-01T23:59:59.000Z

    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

  1. Scaling of convective velocity in a vertically vibrated granular bed

    E-Print Network [OSTI]

    Tomoya M. Yamada; Hiroaki Katsuragi

    2014-05-30T23:59:59.000Z

    We experimentally study the velocity scaling of granular convection which is a possible mechanism of the regolith migration on the surface of small asteroids. In order to evaluate the contribution of granular convection to the regolith migration, the velocity of granular convection under the microgravity condition has to be revealed. Although it is hard to control the gravitational acceleration in laboratory experiments, scaling relations involving the gravitational effect can be evaluated by systematic experiments. Therefore, we perform such a systematic experiment of the vibration-induced granular convection. From the experimental data, a scaling form for the granular convective velocity is obtained. The obtained scaling form implies that the granular convective velocity can be decomposed into two characteristic velocity components: vibrational and gravitational velocities. In addition, the system size dependence is also scaled. According to the scaling form, the granular convective velocity $v$ depends on the gravitational acceleration $g$ as $v \\propto g^{0.97}$ when the normalized vibrational acceleration is fixed.

  2. Filament velocity scaling laws for warm ions

    SciTech Connect (OSTI)

    Manz, P. [Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany) [Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany); Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Carralero, D.; Birkenmeier, G.; Müller, H. W.; Scott, B. D. [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Müller, S. H. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego 92093 (United States)] [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego 92093 (United States); Fuchert, G. [Insitut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart, 70569 Stuttgart (Germany)] [Insitut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart, 70569 Stuttgart (Germany); Stroth, U. [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany) [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany)

    2013-10-15T23:59:59.000Z

    The dynamics of filaments or blobs in the scrape-off layer of magnetic fusion devices are studied by magnitude estimates of a comprehensive drift-interchange-Alfvén fluid model. The standard blob models are reproduced in the cold ion case. Even though usually neglected, in the scrape-off layer, the ion temperature can exceed the electron temperature by an order of magnitude. The ion pressure affects the dynamics of filaments amongst others by adding up to the interchange drive and the polarisation current. It is shown how both effects modify the scaling laws for filament velocity in dependence of its size. Simplifications for experimentally relevant limit regimes are given. These are the sheath dissipation, collisional, and electromagnetic regime.

  3. Correlation of bubble rise velocity and volume

    SciTech Connect (OSTI)

    Burge, C.

    1991-12-31T23:59:59.000Z

    This project was conducted at Westinghouse`s Savannah River Laboratories (SRL). The goal of SRL is to make certain that the modifications on the reactor are safe for those working at the plant as well as the general public. One of the steps needed to insure safety is the knowledge of the occurrences that result from a plenum pipe breakage. When a plenum pipe breaks, two things occur: air is sucked into the pipe and is trapped in the cooling water; and water used to cool the fuel rods is lost. As a result of these occurrences, the water is slowed down by both the loss in water pressure and the upward force of air bubbles pushing against the downward force of the water. The project required the conducting of tests to find the bubble velocity in an annular ribbed pipe filled with stagnant water. This document discusses the methodology and results of this testing.

  4. Correlation of bubble rise velocity and volume

    SciTech Connect (OSTI)

    Burge, C.

    1991-01-01T23:59:59.000Z

    This project was conducted at Westinghouse's Savannah River Laboratories (SRL). The goal of SRL is to make certain that the modifications on the reactor are safe for those working at the plant as well as the general public. One of the steps needed to insure safety is the knowledge of the occurrences that result from a plenum pipe breakage. When a plenum pipe breaks, two things occur: air is sucked into the pipe and is trapped in the cooling water; and water used to cool the fuel rods is lost. As a result of these occurrences, the water is slowed down by both the loss in water pressure and the upward force of air bubbles pushing against the downward force of the water. The project required the conducting of tests to find the bubble velocity in an annular ribbed pipe filled with stagnant water. This document discusses the methodology and results of this testing.

  5. Single-mode fiber, velocity interferometry

    SciTech Connect (OSTI)

    Krauter, K. G.; Jacobson, G. F.; Patterson, J. R.; Nguyen, J. H.; Ambrose, W. P. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore California 94551 (United States)

    2011-04-15T23:59:59.000Z

    In this paper, we describe a velocity interferometer system based entirely on single-mode fiber optics. This paper includes a description of principles used in developing the single-mode velocity interferometry system (SMV). The SMV design is based on polarization-insensitive components. Polarization adjusters are included to eliminate the effects of residual birefringence and polarization dependent losses in the interferometers. Characterization measurements and calibration methods needed for data analysis and a method of data analysis are described. Calibration is performed directly using tunable lasers. During development, we demonstrated its operation using exploding-foil bridge-wire fliers up to 200 m/s. In a final test, we demonstrated the SMV in a gas gun experiment up to 1.2 km/sec. As a basis for comparison in the gas gun experiment, we used another velocimetry technique that is also based on single-mode fiber optics: photonic Doppler velocimetry (PDV). For the gas gun experiment, we split the light returned from a single target spot and performed a direct comparison of the homodyne (SMV) and heterodyne (PDV) techniques concurrently. The two techniques had a negligible mean difference and a 1.5% standard deviation in the one-dimensional shock zone. Within one interferometer delay time after a sudden Doppler shift, a SMV unencumbered by multimode-fiber dispersion exhibits two color beats. These beats have the same period as PDV beats--this interference occurs between the ''recently'' shifted and ''formerly unshifted'' paths within the interferometer. We believe that recognizing this identity between homodyne and heterodyne beats is novel in the shock-physics field. SMV includes the conveniences of optical fiber, while removing the time resolution limitations associated with the multimode delivery fiber.

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

    E-Print Network [OSTI]

    Ensemble Kalman Filter Assimilation of Simulated HIWRAP Doppler Velocity Data in a Hurricane JASON (Manuscript received 29 May 2012, in final form 16 January 2013) ABSTRACT This study utilizes ensemble Kalman Kalman filter (EnKF) assimilation of high-resolution observations from tropical cyclones can improve

  7. Author's personal copy Effects of crossflow velocity and transmembrane pressure on microfiltration

    E-Print Network [OSTI]

    Priezjev, Nikolai V.

    Author's personal copy Effects of crossflow velocity and transmembrane pressure on microfiltration, at the same time, high rejection rate of the oil phase. The effects of transmembrane pressure and crossflow-section are investigated numerically by solving the Navier­Stokes equation. We found that in the absence of crossflow

  8. Initial Examination of Low Velocity Sphere Impact of Glass Ceramics

    SciTech Connect (OSTI)

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

    2012-06-01T23:59:59.000Z

    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.

  9. Note: Simultaneous measurement of transverse speed and axial velocity from a single optical beam

    SciTech Connect (OSTI)

    Moro, Erik A.; Briggs, Matthew E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2013-01-15T23:59:59.000Z

    A method is introduced for simultaneously measuring transverse speed and axial velocity using a single optical beam and a standard photon Doppler velocimetry (PDV) sensing architecture. This result is of particular interest given the recent, widespread use of PDV and the fact that optical velocimetry has thus far been limited to measuring motion in one dimension per probe. Further, this result demonstrates that both axial velocity data and transverse speed data (at least qualitative) may be obtained entirely through signal analysis; not requiring hardware modification. This result is immediately relevant to analyses of existing PDV data and to future efforts in high-speed optical velocimetry.

  10. Natural discharge after pulse and cooperative electrodes to enhance droplet velocity in digital microfluidics

    SciTech Connect (OSTI)

    Chen, Tianlan; Dong, Cheng; Gao, Jie; Jia, Yanwei; Mak, Pui-In, E-mail: pimak@umac.mo; Vai, Mang-I; Martins, Rui P. [State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE, University of Macau, Macao (China)] [State Key Laboratory of Analog and Mixed-Signal VLSI and FST-ECE, University of Macau, Macao (China)

    2014-04-15T23:59:59.000Z

    Digital Microfluidics (DMF) is a promising technology for biological/chemical micro-reactions due to its distinct droplet manageability via electronic automation, but the limited velocity of droplet transportation has hindered DMF from utilization in high throughput applications. In this paper, by adaptively fitting the actuation voltages to the dynamic motions of droplet movement under real-time feedback monitoring, two control-engaged electrode-driving techniques: Natural Discharge after Pulse (NDAP) and Cooperative Electrodes (CE) are proposed. They together lead to, for the first time, enhanced droplet velocity with lower root mean square voltage value.

  11. On the velocity-strengthening behavior of dry friction

    E-Print Network [OSTI]

    Yohai Bar-Sinai; Robert Spatschek; Efim A. Brener; Eran Bouchbinder

    2014-04-15T23:59:59.000Z

    The onset of frictional instabilities, e.g. earthquakes nucleation, is intimately related to velocity-weakening friction, in which the frictional resistance of interfaces decreases with increasing slip velocity. While this frictional response has been studied extensively, less attention has been given to steady-state velocity-strengthening friction, in spite of its potential importance for various aspects of frictional phenomena such as the propagation speed of interfacial rupture fronts and the amount of stored energy released by them. In this note we suggest that a crossover from steady-state velocity-weakening friction at small slip velocities to steady-state velocity-strengthening friction at higher velocities might be a generic feature of dry friction. We further argue that while thermally activated rheology naturally gives rise to logarithmic steady-state velocity-strengthening friction, a crossover to stronger-than-logarithmic strengthening might take place at higher slip velocities, possibly accompanied by a change in the dominant dissipation mechanism. We sketch a few physical mechanisms that may account for the crossover to stronger-than-logarithmic steady-state velocity-strengthening and compile a rather extensive set of experimental data available in the literature, lending support to these ideas.

  12. TANGENTIAL VELOCITY OF THE DARK MATTER IN THE BULLET CLUSTER FROM PRECISE LENSED IMAGE REDSHIFTS

    SciTech Connect (OSTI)

    Molnar, Sandor M. [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China); Broadhurst, Tom [Fisika Teorikoa, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea UPV/EHU, 644 Posta Kutxatila, E-48080 Bilbao (Spain); Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Zitrin, Adi [Universitaet Heidelberg, Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Philosophenweg 12, D-69120 Heidelberg (Germany); Rephaeli, Yoel; Shimon, Meir, E-mail: sandor@phys.ntu.edu.tw [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

    2013-09-01T23:59:59.000Z

    We show that the fast-moving component of the ''Bullet Cluster'' (1E0657-56) can induce potentially resolvable redshift differences between multiply lensed images of background galaxies. This moving cluster effect, due to the tangential peculiar velocity of the lens, can be expressed as the scalar product of the lensing deflection angle with the tangential velocity of the mass components; the effect is maximal for clusters colliding in the plane of the sky with velocities boosted by their mutual gravity. The Bullet Cluster is likely to be the best candidate for the first measurement of this effect due to the large collision velocity and because the lensing deflection and the cluster fields can be calculated in advance. We derive the deflection field using multiply lensed background galaxies detected with the Hubble Space Telescope. The velocity field is modeled using self-consistent N-body/hydrodynamical simulations constrained by the observed X-ray and gravitational lensing features of this system. We predict that the triply lensed images of systems ''G'' and ''H'' straddling the critical curve of the bullet component will show the largest frequency shifts up to {approx}0.5 km s{sup -1}. These shifts are within the range of the Atacama Large Millimeter/Submillimeter Array for molecular emission, and are near the resolution limit of the new generation high-throughput optical-IR spectrographs. The detection of this effect measures the tangential motion of the subclusters directly, thereby clarifying the tension with {Lambda}CDM, which is inferred from the gas motion less directly. This method may be extended to smaller redshift differences using the Ly{alpha} forest toward QSOs lensed by more typical clusters of galaxies. More generally, the tangential component of the peculiar velocities of clusters derived by our method complements the radial component determined by the kinematic Sunyaev-Zel'dovich effect, providing a full three-dimensional description of velocities.

  13. NON-GAUSSIAN STATISTICS AND STELLAR ROTATIONAL VELOCITIES OF MAIN-SEQUENCE FIELD STARS

    SciTech Connect (OSTI)

    Carvalho, J. C.; Do Nascimento, J. D.; Silva, R.; De Medeiros, J. R. [Universidade Federal do Rio Grande do Norte, UFRN, Departamento de Fisica, C. P. 1641, Natal, RN 59072-970 (Brazil)

    2009-05-01T23:59:59.000Z

    In this Letter, we study the observed distributions of rotational velocity in a sample of more than 16,000 nearby F and G dwarf stars, magnitude complete, and presenting high-precision Vsin i measurements. We show that the velocity distributions cannot be fitted by a Maxwellian. In addition, an analysis based on both Tsallis and Kaniadakis power-law statistics is by far the most appropriate statistics and gives a very good fit. It is also shown that single and binary stars have similar rotational distributions. This is the first time, to our knowledge, that these two new statistics have been tested for the rotation of such a large sample of stars, pointing solidly to a solution of the puzzling problem of the function governing the distribution of stellar rotational velocity.

  14. TEMPLATE RR LYRAE H{alpha}, H{beta}, AND H{gamma} VELOCITY CURVES

    SciTech Connect (OSTI)

    Sesar, Branimir, E-mail: bsesar@astro.caltech.edu [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-10-01T23:59:59.000Z

    We present template radial velocity curves of ab-type RR Lyrae stars constructed from high-precision measurements of H{alpha}, H{beta}, and H{gamma} lines. Amplitude correlations between the Balmer line velocity curves, Johnson V band, and Sloan Digital Sky Survey (SDSS) g- and r-band light curves are also derived. Compared to previous methods, these templates and derived correlations reduce the uncertainty in measured systemic (center-of-mass) velocities of RR Lyrae stars by up to 15 km s{sup -1}, and will be of particular interest to wide-area spectroscopic surveys such as the SDSS and LAMOST Experiment for Galactic Understanding and Exploration.

  15. Time-resolved particle velocity measurements at impact velocities of 10 km/s

    SciTech Connect (OSTI)

    Furnish, M.D.; Chhabildas, L.C.; Reinhart, W.D.

    1998-08-01T23:59:59.000Z

    Hypervelocity launch capabilities (9--16 km/s) with macroscopic plates have become available in recent years. It is now feasible to conduct instrumented plane-wave tests using this capability. Successfully conducting such tests requires a planar launch and impact at hypervelocities, appropriate triggering for recording systems, and time-resolved measurements of motion or stress at a particular point or set of points within the target or projectile during impact. The authors have conducted the first time-resolved wave-profile experiments using velocity interferometric techniques at impact velocities of 10 km/s. These measurements show that aluminum continues to exhibit normal release behavior to 161 GPa shock pressure, with complete loss of strength of the shocked state. These experiments have allowed a determination of shock-wave window transparency in conditions produced by a hypervelocity impact. In particular, lithium fluoride appears to lose transparency at a shock stress of 200 GPa; this appears to be the upper limit for conventional wave profile measurements using velocity interferometric techniques.

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

    E-Print Network [OSTI]

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

    2007-07-13T23:59:59.000Z

    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.

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

    E-Print Network [OSTI]

    Sedarsky, David; Blaisot, Jean-Bernard; Rozé, Claude

    2013-01-01T23:59:59.000Z

    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...

  18. Out-of-plane ultrasonic velocity measurement

    DOE Patents [OSTI]

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

    1998-07-14T23:59:59.000Z

    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.

  19. True Masses of Radial-Velocity Exoplanets

    E-Print Network [OSTI]

    Brown, Robert A

    2015-01-01T23:59:59.000Z

    We explore the science power of space telescopes used to estimate the true masses of known radial-velocity exoplanets by means of astrometry on direct images. We translate a desired mass accuracy (+/10% in our example) into a minimum goal for the signal-to-noise ratio, which implies a minimum exposure time. When the planet is near a node, the mass measurement becomes difficult if not impossible, because the apparent separation becomes decoupled from the inclination angle of the orbit. The combination of this nodal effect with considerations of solar and anti-solar pointing restrictions, photometric and obscurational completeness, and image blurring due to orbital motion, severely limits the observing opportunities, often to only brief intervals in a five-year mission. We compare the science power of four missions, two with external star shades, EXO-S and WFIRST-S, and two with internal coronagraphs, EXO-C and WFIRST-C. The star shades out-perform the coronagraph in this science program by about a factor of th...

  20. Out-of-plane ultrasonic velocity measurement

    DOE Patents [OSTI]

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

    1998-01-01T23:59:59.000Z

    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.

  1. Limiting velocities as running parameters and superluminal neutrinos

    E-Print Network [OSTI]

    Mohamed M. Anber; John F. Donoghue

    2011-10-01T23:59:59.000Z

    In the context of theories where particles can have different limiting velocities, we review the running of particle speeds towards a common limiting velocity at low energy. Motivated by the recent OPERA experimental results, we describe a model where the neutrinos would deviate from the common velocity by more than do other particles in the theory, because their running is slower due to weaker interactions.

  2. The thin section rock physics: Modeling and measurement of seismic wave velocity on the slice of carbonates

    SciTech Connect (OSTI)

    Wardaya, P. D., E-mail: pongga.wardaya@utp.edu.my; Noh, K. A. B. M., E-mail: pongga.wardaya@utp.edu.my; Yusoff, W. I. B. W., E-mail: pongga.wardaya@utp.edu.my [Petroleum Geosciences Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Ridha, S. [Petroleum Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak, 31750 (Malaysia); Nurhandoko, B. E. B. [Wave Inversion and Subsurface Fluid Imaging Research Laboratory (WISFIR), Dept. of Physics, Institute of Technology Bandung, Bandung, Indonesia and Rock Fluid Imaging Lab, Bandung (Indonesia)

    2014-09-25T23:59:59.000Z

    This paper discusses a new approach for investigating the seismic wave velocity of rock, specifically carbonates, as affected by their pore structures. While the conventional routine of seismic velocity measurement highly depends on the extensive laboratory experiment, the proposed approach utilizes the digital rock physics view which lies on the numerical experiment. Thus, instead of using core sample, we use the thin section image of carbonate rock to measure the effective seismic wave velocity when travelling on it. In the numerical experiment, thin section images act as the medium on which wave propagation will be simulated. For the modeling, an advanced technique based on artificial neural network was employed for building the velocity and density profile, replacing image's RGB pixel value with the seismic velocity and density of each rock constituent. Then, ultrasonic wave was simulated to propagate in the thin section image by using finite difference time domain method, based on assumption of an acoustic-isotropic medium. Effective velocities were drawn from the recorded signal and being compared to the velocity modeling from Wyllie time average model and Kuster-Toksoz rock physics model. To perform the modeling, image analysis routines were undertaken for quantifying the pore aspect ratio that is assumed to represent the rocks pore structure. In addition, porosity and mineral fraction required for velocity modeling were also quantified by using integrated neural network and image analysis technique. It was found that the Kuster-Toksoz gives the closer prediction to the measured velocity as compared to the Wyllie time average model. We also conclude that Wyllie time average that does not incorporate the pore structure parameter deviates significantly for samples having more than 40% porosity. Utilizing this approach we found a good agreement between numerical experiment and theoretically derived rock physics model for estimating the effective seismic wave velocity of rock.

  3. acoustic wave velocity: Topics by E-print Network

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

    the offered analytical method the determinant relation for a phase velocities of elastic waves for an arbitrary propagation directions in a piezoelectric crystal are received. The...

  4. aggregate sound velocities: Topics by E-print Network

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

    an acoustic loop filter Physics Websites Summary: observation of negative group velocity propagation of sound waves through an asymmetric loop filterSound beyond the speed of...

  5. Crust and Upper Mantle P Wave Velocity Structure Beneath Valles...

    Open Energy Info (EERE)

    Crust and Upper Mantle P Wave Velocity Structure Beneath Valles Caldera, New Mexico- Results from the Jemez Teleseismic Tomography Experiment Jump to: navigation, search OpenEI...

  6. adiabatic burning velocity: Topics by E-print Network

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

    Sciences Websites Summary: burning velocities under conditions for which the net heat loss of the flame is zero. Very similar values, France 2 IFP Energies nouvelles, 1 et...

  7. Modified definition of group velocity and electromagnetic energy conservation equation

    E-Print Network [OSTI]

    Changbiao Wang

    2015-01-19T23:59:59.000Z

    The classical definition of group velocity has two flaws: (a) the group velocity can be greater than the phase velocity in a non-dispersive, lossless, non-conducting, anisotropic uniform medium; (b) the definition is not consistent with the principle of relativity for a plane wave in a moving isotropic uniform medium. 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.

  8. USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP SUBSURFACE...

    Open Energy Info (EERE)

    GEOTHERMAL FIELD, CALIFORNIA Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Proceedings: USING MICRO-SEISMICITY AND SEISMIC VELOCITIES TO MAP...

  9. Using Micro-Seismicity and Seismic Velocities to Map Subsurface...

    Open Energy Info (EERE)

    Geothermal Field California Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Using Micro-Seismicity and Seismic Velocities to Map Subsurface...

  10. A novel photonic Doppler velocimetry for transverse velocity measurement

    SciTech Connect (OSTI)

    Chen Guanghua; Wang Detian; Liu Jun; Meng Jianhua; Liu Shouxian; Yang Qingguo [Institute of Fluid Physics, CAEP, P.O. Box 919-109, Mianyang, Sichuan 621900 (China)

    2013-01-15T23:59:59.000Z

    A fiber interferometry for transverse velocity measurement has been developed. This diagnostic is similar to photonic Doppler velocimetry in the way in which laser propagates and couples. The interferometer mainly consists of a fiber coupler, an emitting probe, and two receiving probes. A pair of scattered laser beams mix in the coupler and generates fringes with frequency proportional to transverse velocity. Measurement of transverse velocity is independent of longitudinal velocity. The feasibility of the technique has been verified by rotating wheel experiment and shock loading experiment.

  11. Determination of Surface Exciton Energies by Velocity Resolved...

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

    Exciton Energies by Velocity Resolved Atomic Desorption. Abstract: We have developed a new method for determining surface exciton band energies in alkali halides based on...

  12. anisotropic electron velocity: Topics by E-print Network

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

    A simple model reflecting Cerveny, Vlastislav 8 Anisotropic velocity distributions in 3D dissipative optical lattices Quantum Physics (arXiv) Summary: We present a direct...

  13. air stream velocities: Topics by E-print Network

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

    the early universe, substantial relative "stream" velocities between the gas and dark matter arise due to radiation pressure and persist after recombination. To asses the impact...

  14. Nonlinear peculiar-velocity analysis and PCA

    SciTech Connect (OSTI)

    Dekel, A. [and others

    2001-02-20T23:59:59.000Z

    We allow for nonlinear effects in the likelihood analysis of peculiar velocities, and obtain {approximately}35%-lower values for the cosmological density parameter and for the amplitude of mass-density fluctuations. The power spectrum in the linear regime is assumed to be of the flat {Lambda}CDM model (h = 0:65, n = 1) with only {Omega}{sub m} free. Since the likelihood is driven by the nonlinear regime, we break the power spectrum at k{sub b} {approximately} 0.2 (h{sup {minus}1} Mpc){sup {minus}1} and fit a two-parameter power-law at k > k{sub b} . This allows for an unbiased fit in the linear regime. Tests using improved mock catalogs demonstrate a reduced bias and a better fit. We find for the Mark III and SFI data {Omega}{sub m} = 0.35 {+-} 0.09 with {sigma}{sub 8}{Omega}P{sub m}{sup 0.6} = 0.55 {+-} 0.10 (90% errors). When allowing deviations from {Lambda}CDM, we find an indication for a wiggle in the power spectrum in the form of an excess near k {approximately} 0.05 and a deficiency at k {approximately} 0.1 (h{sup {minus}1} Mpc){sup {minus}1}--a cold flow which may be related to a feature indicated from redshift surveys and the second peak in the CMB anisotropy. A {chi}{sup 2} test applied to principal modes demonstrates that the nonlinear procedure improves the goodness of fit. The Principal Component Analysis (PCA) helps identifying spatial features of the data and fine-tuning the theoretical and error models. We address the potential for optimal data compression using PCA.

  15. The Pathfinder Testbed: Exploring Techniques for Achieving Precision Radial Velocities in the Near-Infrared

    E-Print Network [OSTI]

    Ramsey, Larry; Redman, Stephen; Bender, Chad; Roy, Arpita; Zonak, Stephanie; Sigurdsson, Steinn; Wolszczan, Alex

    2010-01-01T23:59:59.000Z

    The Penn State Pathfinder is a prototype warm fiber-fed Echelle spectrograph with a Hawaii-1 NIR detector that has already demonstrated 7-10 m/s radial velocity precision on integrated sunlight. The Pathfinder testbed was initially setup for the Gemini PRVS design study to enable a systematic exploration of the challenges of achieving high radial velocity precision in the near-infrared, as well as to test possible solutions to these calibration challenges. The current version of the Pathfinder has an R3 echelle grating, and delivers a resolution of R~50,000 in the Y, J or H bands of the spectrum. We will discuss the on sky-performance of the Pathfinder during an engineering test run at the Hobby Eberly Telescope as well the results of velocity observations of M dwarfs. We will also discuss the unique calibration techniques we have explored, like Uranium-Neon hollow cathode lamps, notch filter, and modal noise mitigation to enable high precision radial velocity observation in the NIR. The Pathfinder is a proto...

  16. Hydrocarbon saturation determination using acoustic velocities obtained through casing

    DOE Patents [OSTI]

    Moos, Daniel (Houston, TX)

    2010-03-09T23:59:59.000Z

    Compressional and shear velocities of earth formations are measured through casing. The determined compressional and shear velocities are used in a two component mixing model to provides improved quantitative values for the solid, the dry frame, and the pore compressibility. These are used in determination of hydrocarbon saturation.

  17. Measurements of Laminar Flame Velocity for Components of Natural Gas

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    flame velocity of components of natural gas, methane, ethane, propane, and nbutane as well as of binary% by volume (1). The laminar flame velocities of methane/air, ethane/air, and propane/air mixtures have on a plenum chamber with the radial temperature distribution measurement made by a series of thermocouples

  18. A laser Doppler method for noninvasive measurement of flow velocity

    SciTech Connect (OSTI)

    Biggs, G.L.

    1986-11-25T23:59:59.000Z

    Laser Doppler velocimetry is a powerful optical technique for noninvasively obtaining experimental flow-velocity data. This paper describes the principle of operation and various optical configurations of the laser Doppler velocimeter. As a sample application, we describe an experimental apparatus for measuring the velocity flow field around a cylinder, and give our experimental results.

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

    DOE Patents [OSTI]

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

    1987-06-08T23:59:59.000Z

    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.

  20. A comparison of light and velocity variations in Semiregular variables

    E-Print Network [OSTI]

    T. Lebzelter; L. L. Kiss; K. H. Hinkle

    2000-09-21T23:59:59.000Z

    NIR velocity variations are compared with simultaneous visual light curves for a sample of late-type semiregular variables (SRV). Precise radial velocity measurements are also presented for the SRV V450 Aql. Our aim is to investigate the nature of the irregular light changes found in these variables. Light and velocity variations are correlated in all stars of our sample. Based on these results we discuss several possibilities to explain the observed behavior. We find that pulsation is responsible for large amplitude variations. In a recent paper Lebzelter (1999) invoked large convective cells to understand observed velocity variations. This possibility is discussed with respect to the observed correlation between light and velocity changes. In the light of these results we investigate the origin of the semiregular variations.

  1. Precision Measuring of Velocities via the Relativistic Doppler Effect

    E-Print Network [OSTI]

    Leonid M. Ozernoy

    1997-12-26T23:59:59.000Z

    Just as the ordinary Doppler effect serves as a tool to measure radial velocities of celestial objects, so can the relativistic Doppler effect be implemented to measure a combination of radial and transverse velocities by using recent improvements in observing techniques. A key element that makes a further use of this combination feasible is the periodicity in changes of the orbital velocity direction for the source. Two cases are considered: (i) a binary star; and (ii) a solitary star with the planetary companion. It is shown that, in case (i), several precision Doppler measurements employing the gas absorption cell technique would determine both the total orbital velocity and the inclination angle of the binary orbit disentangled from the peculiar velocity of the system. The necessary condition for that is the measured, at least with a modest precision, proper motion and distance to the system.

  2. Precision Measuring of Velocities via the Relativistic Doppler Effect

    E-Print Network [OSTI]

    Ozernoy, L M

    1997-01-01T23:59:59.000Z

    Just as the ordinary Doppler effect serves as a tool to measure radial velocities of celestial objects, so can the relativistic Doppler effect be implemented to measure a combination of radial and transverse velocities by using recent improvements in observing techniques. A key element that makes a further use of this combination feasible is the periodicity in changes of the orbital velocity direction for the source. Two cases are considered: (i) a binary star; and (ii) a solitary star with the planetary companion. It is shown that, in case (i), several precision Doppler measurements employing the gas absorption cell technique would determine both the total orbital velocity and the inclination angle of the binary orbit disentangled from the peculiar velocity of the system. The necessary condition for that is the measured, at least with a modest precision, proper motion and distance to the system.

  3. Discrimination of porosity and fluid saturation using seismic velocity analysis

    DOE Patents [OSTI]

    Berryman, James G. (Danville, CA)

    2001-01-01T23:59:59.000Z

    The method of the invention is employed for determining the state of saturation in a subterranean formation using only seismic velocity measurements (e.g., shear and compressional wave velocity data). Seismic velocity data collected from a region of the formation of like solid material properties can provide relatively accurate partial saturation data derived from a well-defined triangle plotted in a (.rho./.mu., .lambda./.mu.)-plane. When the seismic velocity data are collected over a large region of a formation having both like and unlike materials, the method first distinguishes the like materials by initially plotting the seismic velocity data in a (.rho./.lambda., .mu./.lambda.)-plane to determine regions of the formation having like solid material properties and porosity.

  4. Effects of crossflow velocity and transmembrane pressure on microfiltration of oil-in-water emulsions

    E-Print Network [OSTI]

    Darvishzadeh, Tohid

    2012-01-01T23:59:59.000Z

    This study addresses the issue of oil removal from water using hydrophilic porous membranes. The effective separation of oil-in-water dispersions involves high flux of water through the membrane and, at the same time, high rejection rate of the oil phase. The effects of transmembrane pressure and crossflow velocity on rejection of oil droplets and thin oil films by pores of different cross-section are investigated numerically by solving the Navier-Stokes equation. We found that in the absence of crossflow, the critical transmembrane pressure, which is required for the oil droplet entry into a circular pore of a given surface hydrophilicity, agrees well with analytical predictions based on the Young-Laplace equation. With increasing crossflow velocity, the shape of the oil droplet is strongly deformed near the pore entrance and the critical pressure of permeation increases. We determined numerically the phase diagram for the droplet rejection, permeation, and breakup depending of the transmembrane pressure and...

  5. Stellar Velocity Dispersion of the Leo A Dwarf Galaxy

    E-Print Network [OSTI]

    Warren R. Brown; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz

    2007-05-08T23:59:59.000Z

    We measure the first stellar velocity dispersion of the Leo A dwarf galaxy, \\sigma = 9.3 +- 1.3 km/s. We derive the velocity dispersion from the radial velocities of ten young B supergiants and two HII regions in the central region of Leo A. We estimate a projected mass of 8 +- 2.7 x10^7 solar masses within a radius of 2 arcmin, and a mass to light ratio of at least 20 +- 6 M_sun/L_sun. These results imply Leo A is at least ~80% dark matter by mass.

  6. Two-stream instability with time-dependent drift velocity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qin, Hong [PPPL; Davidson, Ronald C. [PPPL

    2014-01-01T23:59:59.000Z

    The classical two-stream instability driven by a constant relative drift velocity between two plasma components is extended to the case with time-dependent drift velocity. A solution method is developed to rigorously define and calculate the instability growth rate for linear perturbations relative to the time-dependent unperturbed two-stream motions. Stability diagrams for the oscillating two-stream instability are presented over a large region of parameter space. It is shown that the growth rate for the classical two-stream instability can be significantly reduced by adding an oscillatory component to the relative drift velocity.

  7. Measuring Oscillatory Velocity Fields Due to Swimming Algae

    E-Print Network [OSTI]

    Guasto, Jeffrey S; Gollub, J P

    2010-01-01T23:59:59.000Z

    In this fluid dynamics video, we present the first time-resolved measurements of the oscillatory velocity field induced by swimming unicellular microorganisms. Confinement of the green alga C. reinhardtii in stabilized thin liquid films allows simultaneous tracking of cells and tracer particles. The measured velocity field reveals complex time-dependent flow structures, and scales inversely with distance. The instantaneous mechanical power generated by the cells is measured from the velocity fields and peaks at 15 fW. The dissipation per cycle is more than four times what steady swimming would require.

  8. Two-stream instability with time-dependent drift velocity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Qin, Hong; Davidson, Ronald C.

    2014-06-01T23:59:59.000Z

    The classical two-stream instability driven by a constant relative drift velocity between two plasma components is extended to the case with time-dependent drift velocity. A solution method is developed to rigorously define and calculate the instability growth rate for linear perturbations relative to the time-dependent unperturbed two-stream motions. Stability diagrams for the oscillating two-stream instability are presented over a large region of parameter space. It is shown that the growth rate for the classical two-stream instability can be significantly reduced by adding an oscillatory component to the relative drift velocity.

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

    SciTech Connect (OSTI)

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

    2008-10-01T23:59:59.000Z

    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.

  10. Probing dark energy models with extreme pairwise velocities of galaxy clusters from the DEUS-FUR simulations

    E-Print Network [OSTI]

    Bouillot, Vincent R; Corasaniti, Pier-Stefano; Rasera, Yann

    2015-01-01T23:59:59.000Z

    Observations of colliding galaxy clusters with high relative velocity probe the tail of the halo pairwise velocity distribution with the potential of providing a powerful test of cosmology. As an example it has been argued that the discovery of the Bullet Cluster challenges standard $\\Lambda$CDM model predictions. Halo catalogs from N-body simulations have been used to estimate the probability of Bullet-like clusters. However, due to simulation volume effects previous studies had to rely on a Gaussian extrapolation of the pairwise velocity distribution to high velocities. Here, we perform a detail analysis using the halo catalogs from the Dark Energy Universe Simulation Full Universe Runs (DEUS-FUR), which enables us to resolve the high-velocity tail of the distribution and study its dependence on the halo mass definition, redshift and cosmology. Building upon these results we estimate the probability of Bullet-like systems in the framework of Extreme Value Statistics. We show that the tail of extreme pairwis...

  11. Multipole seismoelectric logging while drilling (LWD) for acoustic velocity measurements

    E-Print Network [OSTI]

    Zhu, Zhenya

    2012-01-01T23:59:59.000Z

    In seismoelectric well logging, an acoustic wave propagates along a borehole and induces electrical signals along the borehole wall. The apparent velocities of these seismoelectric signals are equal to the formation ...

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

    Open Energy Info (EERE)

    times Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: P wave velocity variations in the Coso region, California, derived from local earthquake...

  13. LOW VELOCITY SHPERE IMPACT OF SODA LIME SILICATE GLASS

    SciTech Connect (OSTI)

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

    2012-01-01T23:59:59.000Z

    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.

  14. air velocity distribution: Topics by E-print Network

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

    Page Topic Index 1 Carbon isotope evidence for the latitudinal distribution and wind speed dependence of the air-sea gas transfer velocity University of California eScholarship...

  15. Superluminal Velocity of Photons in a Gravitational Background

    E-Print Network [OSTI]

    I. B. Khriplovich

    1994-11-20T23:59:59.000Z

    The influence of radiative corrections on the photon propagation in a gravitational background is investigated without the low-frequency approximation $\\omega \\ll m$. The conclusion is made in this way that the velocity of light can exceed unity.

  16. artery peak velocity: Topics by E-print Network

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

    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...

  17. Seismic Velocity And Attenuation Structure Of The Geysers Geothermal...

    Open Energy Info (EERE)

    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...

  18. Effective velocities in fractured media: a numerical study using the ...

    E-Print Network [OSTI]

    2002-03-18T23:59:59.000Z

    theories that predict the effective P- and S-wave velocities in fractured materials in ... can be treated only by numerical techniques because analyt- ... apply the rotated staggered grid (Saenger, Gold and Shapiro ..... (r ? 0:2) and for SH-

  19. WIYN open cluster study. LIX. Radial velocity membership of the evolved population of the old open cluster NGC 6791

    SciTech Connect (OSTI)

    Tofflemire, Benjamin M.; Gosnell, Natalie M.; Mathieu, Robert D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Platais, Imants, E-mail: tofflemi@astro.wisc.edu, E-mail: imants@pha.jhu.edu [Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States)

    2014-10-01T23:59:59.000Z

    The open cluster NGC 6791 has been the focus of much recent study due to its intriguing combination of old age and high metallicity (?8 Gyr, [Fe/H] = +0.30), as well as its location within the Kepler field. As part of the WIYN Open Cluster Study, we present precise (? = 0.38 km s{sup –1}) radial velocities for proper motion candidate members of NGC 6791 from Platais et al. Our survey, extending down to g' ? 16.8, is comprised of the evolved cluster population, including blue stragglers, giants, and horizontal branch stars. Of the 280 proper-motion-selected stars above our magnitude limit, 93% have at least one radial velocity measurement and 79% have three measurements over the course of at least 200 days, sufficient for secure radial-velocity-determined membership of non-velocity-variable stars. The Platais et al. proper motion catalog includes 12 anomalous horizontal branch candidates blueward of the red clump, of which we find only 4 to be cluster members. Three fall slightly blueward of the red clump and the fourth is consistent with being a blue straggler. The cleaned color-magnitude diagram shows a richly populated red giant branch and a blue straggler population. Half of the blue stragglers are in binaries. From our radial velocity measurement distribution, we find the cluster's radial velocity dispersion to be ? {sub c} = 0.62 ± 0.10 km s{sup –1}. This corresponds to a dynamical mass of ?4600 M {sub ?}.

  20. Estimating propagation velocity through a surface acoustic wave sensor

    SciTech Connect (OSTI)

    Xu, Wenyuan (Oakdale, MN); Huizinga, John S. (Dellwood, MN)

    2010-03-16T23:59:59.000Z

    Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

  1. Velocity of sound in solid methane near melting temperatures

    E-Print Network [OSTI]

    Whitehead, John Martin

    1968-01-01T23:59:59.000Z

    VELOCITY OF SOUND IN SOLID METHANE NEAR MELTING TEMPERATURES A Thesis By JOHN MARTIN WHITEHEAD Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May... 1968 Ma)or Sub)ect: Physics VELOCITY OF SOVND IN SOLID METHANE NEAR MELTING TEMPERATURES A Thesis By JOHN MARTIN WHITEHEAD Approved as to style and content by& (Chairman of Committee) (Head of Departsmnt) (Mem er (Member) May 1968...

  2. Seismic velocity inversion by differential semblance optimization

    SciTech Connect (OSTI)

    Gockenbach, M.; Symes, W.; Tapia, R.

    1994-12-31T23:59:59.000Z

    Differential Semblance Optimization (DSO) is a novel way of approaching certain inverse problems that arise in exploration seismology. The standard method of formulating these inverse problems -- Output Least-Squares (OLS) -- leads to a highly nonconvex objective function and therefore to a global optimization problem. The OLS problem can be rewritten as a partially linear least-squares problem with linear constraints, with the DSO objective function derived from the quadratic penalty function for this problem. It is shown that, because of the nature of the operators in this problem, the penalty function leads to a globalization procedure: for suitably small values of the penalty parameter, the global minimum of the DSO objective function can be found using local optimization techniques. There is then a path of minimizers, parameterized by the penalty constant, leading to the solution of the OLS problem.

  3. The concentration-velocity dispersion relation in galaxy groups

    E-Print Network [OSTI]

    Andreas Faltenbacher; William G. Mathews

    2007-06-08T23:59:59.000Z

    Based on results from cold dark matter N-body simulations we develop a dynamical model for the evolution of subhaloes within host haloes of galaxy groups. Only subhaloes more massive than 5 times 10^8 M_{sol} at the time of accretion are examined because they are massive enough to possibly host luminous galaxies. As they orbit within a growing host potential the subhaloes are subject to tidal stripping and dynamical friction. We consider groups of equal mass (M_{vir} = 3.9 times 10^{13} M_{sol}) at redshift z=0 but with different concentrations associated with different formation times. We investigate the variation of subhaloe (or satellite galaxy) velocity dispersion with host concentration and/or formation time. In agreement with the Jeans equation the velocity dispersion of subhaloes increases with the host concentration. Between concentrations ~5 and ~20 the subhaloe velocity dispersions increase by ~25 per cent. By applying a simplified tidal disruption criterion, i.e. rejection of all subhaloes with a tidal truncation radius below 3 kpc at z=0, the central velocity dispersion of 'surviving' subhaloes increases substantially for all concentrations. The enhanced central velocity dispersion among surviving subhaloes is caused by a lack of slow tangential motions. Additionally, we present a fitting formula for the velocity anisotropy parameter \\beta(r) which does not depend on concentration if the group-centric distances are scaled by r_s, the characteristic radius of the NFW-profile.

  4. A photoelectron velocity map imaging spectrometer for experiments combining synchrotron and laser radiations

    SciTech Connect (OSTI)

    O'Keeffe, P.; Bolognesi, P.; Coreno, M.; Avaldi, L. [CNR-IMIP, Area della Ricerca di Roma 1, Monterotondo Scalo (Italy); Moise, A.; Richter, R.; Cautero, G.; Stebel, L.; Sergo, R. [Sincrotrone Trieste SCpA, Area Science Park, I-34149 Basovizza (Trieste) (Italy); Pravica, L. [The University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia (Australia); Ovcharenko, Y. [Institute of Electron Physics, 88017 Uzhgorod (Ukraine)

    2011-03-15T23:59:59.000Z

    A velocity map imaging/ion time-of-flight spectrometer designed specifically for pump-probe experiments combining synchrotron and laser radiations is described. The in-house built delay line detector can be used in two modes: the high spatial resolution mode and the coincidence mode. In the high spatial resolution mode a kinetic energy resolution of 6% has been achieved. The coincidence mode can be used to improve signal-to-noise ratio for the pump-probe experiments either by using a gate to count electrons only when the laser is present or by recording coincidences with the ion formed in the ionization process.

  5. The velocity gradient in the pseudo-photosphere of the peculiar supergiant HD101584

    E-Print Network [OSTI]

    Eric J. Bakker

    1995-10-23T23:59:59.000Z

    In this paper preliminary results are presented based on a study of the low and high resolution ultraviolet spectrum of the peculiar supergiant (post-AGB star) HD101584. By a comparison of the low resolution spectrum (1200-3200ang) with standard stars, the star is classified as an A7I, indicating an effective temperature of 8150 K, where literature quotes spectral type F0I. The Doppler shift of the FeII absorption lines in the high resolution spectrum (2500-3000ang) show a relation with the line optical depth. This suggests an expanding accelerating wind, c.q. pseudo-photosphere. The relation is extended by a factor 10^5 in optical depth by using available data from optical HeI and NI lines. The relation suggests that the radial heliocentric velocity of the star is at least 54.5km/s. From the Halpha line a velocity of 96km/s is measured for the terminal velocity of the wind.

  6. The velocity gradient in the pseudo-photosphere of the peculiar supergiant HD101584

    E-Print Network [OSTI]

    Bakker, E J

    1995-01-01T23:59:59.000Z

    In this paper preliminary results are presented based on a study of the low and high resolution ultraviolet spectrum of the peculiar supergiant (post-AGB star) HD101584. By a comparison of the low resolution spectrum (1200-3200ang) with standard stars, the star is classified as an A7I, indicating an effective temperature of 8150 K, where literature quotes spectral type F0I. The Doppler shift of the FeII absorption lines in the high resolution spectrum (2500-3000ang) show a relation with the line optical depth. This suggests an expanding accelerating wind, c.q. pseudo-photosphere. The relation is extended by a factor 10^5 in optical depth by using available data from optical HeI and NI lines. The relation suggests that the radial heliocentric velocity of the star is at least 54.5km/s. From the Halpha line a velocity of 96km/s is measured for the terminal velocity of the wind.

  7. DEPOSITION VELOCITY ESTIMATION WITH THE GENII V2 SOFTWARE

    SciTech Connect (OSTI)

    Hutchins, H.

    2012-04-23T23:59:59.000Z

    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.

  8. Propagation velocities of gas rings in collisional ring galaxies

    E-Print Network [OSTI]

    E. I. Vorobyov; D. Bizyaev

    2003-01-27T23:59:59.000Z

    The propagation velocity of the first gas ring in collisional ring galaxies, i.e. the velocity at which the maximum in the radial gas density profile propagates radially in the galactic disk, is usually inferred from the radial expansion velocity of gas in the first ring. Our numerical hydrodynamics modeling of ring galaxy formation however shows that the maximum radial expansion velocity of gas in the first ring ($v_{gas}$) is invariably below the propagation velocity of the first gas ring itself ($v_{ring}$). Modeling of the Cartwheel galaxy indicates that the outer ring is currently propagating at $v_{ring} \\approx$ 100 km/s, while the maximum radial expansion velocity of gas in the outer ring is currently $v_{gas} \\approx$ 65 km/s. Modeling of the radial B-V/V-K color gradients of the Cartwheel ring galaxy also indicates that the outer ring is propagating at $v_{ring} \\ge $ 90 km/s. We show that a combined effect of inclination, finite thickness, and warping of the Cartwheel's disk might be responsible for the lack of angular difference in the peak positions found for the azimuthally averaged $H\\alpha$, K and B surface brightness profiles of the Cartwheel's outer ring. Indeed, the radial $H\\alpha$ surface brightness profiles obtained along the Cartwheel's major axis, where effects of inclination and finite thickness are minimized, do peak exterior to those at K- and B-bands. The angular difference in peak positions implies $v_{ring}$ = 110 km/s, which is in agreement with the model predictions. We briefly discuss the utility of radio continuum emission and spectral line equivalent widths for determining the propagation velocity of gas rings in collisional ring galaxies.

  9. Extensional wave attenuation and velocity in partially-saturated sand in the sonic frequency range

    SciTech Connect (OSTI)

    Liu, Z.; Rector, J.W.; Nihei, K.T.; Tomutsa, L.; Myer, L.R.; Nakagawa, S.

    2002-06-17T23:59:59.000Z

    Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1 - 9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (QE dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.

  10. Analytic solutions for seismic travel time and ray path geometry through simple velocity models.

    SciTech Connect (OSTI)

    Ballard, Sanford

    2007-12-01T23:59:59.000Z

    The geometry of ray paths through realistic Earth models can be extremely complex due to the vertical and lateral heterogeneity of the velocity distribution within the models. Calculation of high fidelity ray paths and travel times through these models generally involves sophisticated algorithms that require significant assumptions and approximations. To test such algorithms it is desirable to have available analytic solutions for the geometry and travel time of rays through simpler velocity distributions against which the more complex algorithms can be compared. Also, in situations where computational performance requirements prohibit implementation of full 3D algorithms, it may be necessary to accept the accuracy limitations of analytic solutions in order to compute solutions that satisfy those requirements. Analytic solutions are described for the geometry and travel time of infinite frequency rays through radially symmetric 1D Earth models characterized by an inner sphere where the velocity distribution is given by the function V (r) = A-Br{sup 2}, optionally surrounded by some number of spherical shells of constant velocity. The mathematical basis of the calculations is described, sample calculations are presented, and results are compared to the Taup Toolkit of Crotwell et al. (1999). These solutions are useful for evaluating the fidelity of sophisticated 3D travel time calculators and in situations where performance requirements preclude the use of more computationally intensive calculators. It should be noted that most of the solutions presented are only quasi-analytic. Exact, closed form equations are derived but computation of solutions to specific problems generally require application of numerical integration or root finding techniques, which, while approximations, can be calculated to very high accuracy. Tolerances are set in the numerical algorithms such that computed travel time accuracies are better than 1 microsecond.

  11. Exceptional Ground Accelerations and Velocities Caused by Earthquakes

    SciTech Connect (OSTI)

    Anderson, John

    2008-01-17T23:59:59.000Z

    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.

  12. Control of group velocity by phase-changing collisions

    SciTech Connect (OSTI)

    Goren, C.; Rosenbluh, M. [Department of Physics, Bar-Ilan University, Ramat Gan 52900 (Israel); Wilson-Gordon, A.D.; Friedmann, H. [Department of Chemistry, Bar-Ilan University, Ramat Gan 52900 (Israel)

    2005-08-15T23:59:59.000Z

    We discuss the influence of phase-changing collisions on the group velocities in Doppler-broadened, cycling, degenerate two-level systems where F{sub e}=F{sub g}+1 and F{sub g}>0, interacting with pump and probe lasers, that exhibit electromagnetically induced absorption (EIA). Two model systems are considered: the N system where the pump and probe are polarized perpendicularly, and EIA is due to transfer of coherence (TOC), and the double two-level system (TLS) where both lasers have the same polarization, and EIA is due to transfer of population (TOP). For the case of Doppler-broadened EIA TOC, which occurs at low pump intensity, there is a switch from positive to negative dispersion and group velocity, as the rate of phase-changing collisions is increased. For the case of EIA TOP at low pump intensity, the dispersion and group velocity remain negative even when the collision rate is increased. Pressure-induced narrowing, accompanied by an increase in the magnitude of the negative dispersion and a decrease in the magnitude of the negative group velocity, occurs in both EIA TOC and EIA TOP, at low pump intensity. When the pump intensity is increased, a switch from negative to positive dispersion and group velocity, with increasing collision rate, also occurs in the double TLS system. However, the effect is far smaller than in the case of the N system at low pump intensity.

  13. SUBSTRUCTURE IN BULK VELOCITIES OF MILKY WAY DISK STARS

    SciTech Connect (OSTI)

    Carlin, Jeffrey L.; DeLaunay, James; Newberg, Heidi Jo; Gole, Daniel; Grabowski, Kathleen [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)] [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Deng, Licai; Liu, Chao; Luo, A-Li; Zhang, Haotong; Zhao, Gang; Zhao, Yongheng [Key Lab for Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)] [Key Lab for Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Jin, Ge [University of Science and Technology of China, Hefei 230026 (China)] [University of Science and Technology of China, Hefei 230026 (China); Liu, Xiaowei; Yuan, Haibo, E-mail: carlij@rpi.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)] [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2013-11-01T23:59:59.000Z

    We find that Galactic disk stars near the anticenter exhibit velocity asymmetries in both the Galactocentric radial and vertical components across the midplane as well as azimuthally. These findings are based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic velocities for a sample of ?400, 000 F-type stars, combined with proper motions from the PPMXL catalog for which we have derived corrections to the zero points based in part on spectroscopically discovered galaxies and QSOs from LAMOST. In the region within 2 kpc outside the Sun's radius and ±2 kpc from the Galactic midplane, we show that stars above the plane exhibit net outward radial motions with downward vertical velocities, while stars below the plane have roughly the opposite behavior. We discuss this in the context of other recent findings, and conclude that we are likely seeing the signature of vertical disturbances to the disk due to an external perturbation.

  14. The Velocity Field of Quasar Broad Emission Line Gas

    E-Print Network [OSTI]

    Brian Punsly

    2007-01-25T23:59:59.000Z

    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.

  15. Measurement of Poloidal Velocity on the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Ronald E. Bell and Russell Feder

    2010-06-04T23:59:59.000Z

    A diagnostic suite has been developed to measure impurity poloidal flow using charge exchange recombination spectroscopy on the National Spherical Torus Experiment. Toroidal and poloidal viewing systems measure all quantities required to determine the radial electric field. Two sets of up/down symmetric poloidal views are used to measure both active emission in the plane of the neutral heating beams and background emission in a radial plane away from the neutral beams. Differential velocity measurements isolate the line-integrated poloidal velocity from apparent flows due to the energy-dependent chargeexchange cross section. Six f/1.8 spectrometers measure 276 spectra to obtain 75 active and 63 background channels every 10 ms. Local measurements from a similar midplane toroidal viewing system are mapped into two dimensions to allow the inversion of poloidal line-integrated measurements to obtain local poloidal velocity profiles. Radial resolution after inversion is 0.6-1.8 cm from the plasma edge to the center.

  16. Planar velocity analysis of diesel spray shadow images

    E-Print Network [OSTI]

    Sedarsky, David; Blaisot, J-B; Rozé, C

    2012-01-01T23:59:59.000Z

    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...

  17. Measurement of fluid-flow-velocity profile in turbid media by the use of optical Doppler tomography

    SciTech Connect (OSTI)

    Wang, Xiao-Jun; Milner, T.E.; Chen, Zhongping; Nelson, J.S. [Beckman Laser Institute and Medical Clinic, University of California-Irvine, Irvine, California 92715 (United States)]|[Department of Physics, Georgia Southern University, Statesboro, Georgia 30460 (United States)

    1997-01-01T23:59:59.000Z

    Optical Doppler tomography is demonstrated to be a simple, accurate, and noncontact method for measuring the fluid velocity of laminar flow in small-diameter ({approximately}0.5-mm) ducts. Studies are described that utilize circular (square) plastic (glass) ducts infused with a moving suspension of polymer micro-spheres in air and buried in an optically turbid medium. The measurement of Doppler-shifted frequencies of backscattered light from moving microspheres is used to construct a high-resolution spatial profile of fluid-flow velocity in the ducts. {copyright} 1997 Optical Society of America

  18. St. Stephen powerhouse tailrace velocity measurement. Final report

    SciTech Connect (OSTI)

    Fagerburg, T.L.

    1986-09-01T23:59:59.000Z

    Tests were conducted to provide a prototype evaluation of the operating conditions of the project and to evaluate the adequacy of the repairs and remedial work performed in the channel downstream of the tailrace. Prototype measurements were made to define the relative magnitudes of velocities and the surface flow patterns in the channel downstream of the tailrace and the displacement, if any, of the stone protection material resulting from various turbine operations and tailwater conditions. Results of the data collection included determination of (a) velocity distribution at various ranges across the channel; (b) velocity profiles at the toe of the slope and at the observed location of highest velocity; and (c) unusual surface flow patterns that are produced by different combinations of turbine operations. Recommendations for start-up and shut-down procedures for the turbine operations that would produce the most acceptable. The depth soundings revealed that the stone protection material was quite stable (District surveys reveal that no appreciable displacement has occurred during the subsequent months of operation of the powerhouse.) The flow velocities were found to concentrate along the right side of the channel as a result of uneven flow distribution from the draft tube bays and the asymmetrical geometry along the left side of the tailrace. Return flows were observed and found to concentrate along the left side of the channel except when all three turbines were operating. Operating recommendations for the turbines are made based on tailwater conditions, length of time of nonoperation of the powerhouse, and the velocity data obtained from the tests.

  19. Fermi velocity renormalization and dynamical gap generation in graphene

    E-Print Network [OSTI]

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

    2015-01-12T23:59:59.000Z

    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.

  20. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kalesse, Heike

    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. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  1. Edge Turbulence Velocity Changes with Lithium Coating on NSTX

    SciTech Connect (OSTI)

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

    2012-08-10T23:59:59.000Z

    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. __________________________________________________

  2. ELECTROSTATIC MODE ASSOCIATED WITH PINCH VELOCITY IN RFPS

    SciTech Connect (OSTI)

    DELZANNO, GIAN LUCA [Los Alamos National Laboratory; FINN, JOHN M. [Los Alamos National Laboratory; CHACON, LUIS [Los Alamos National Laboratory

    2007-02-08T23:59:59.000Z

    The existence of a new electrostatic instability is shown for RFP (reversed field pinch) equilibria. This mode arises due to the non-zero equilibrium radial flow (pinch flow). In RFP simulations with no-stress boundary conditions on the tangential velocity at the radial wall, this electrostatic mode is unstable and dominates the nonlinear dynamics, even in the presence of the MHD modes typically responsible for the reversal of the axial magnetic field at edge. Nonlinearly, this mode leads to two beams moving azimuthally towards each other, which eventually collide. The electrostatic mode can be controlled by using Dirichlet (no-slip) boundary conditions on the azimuthal velocity at the radial wall.

  3. Extreme Value Analysis of Tidal Stream Velocity Perturbations

    SciTech Connect (OSTI)

    Harding, Samuel; Thomson, Jim; Polagye, Brian; Richmond, Marshall C.; Durgesh, Vibhav; Bryden, Ian

    2011-04-26T23:59:59.000Z

    This paper presents a statistical extreme value analysis of maximum velocity perturbations from the mean flow speed in a tidal stream. This study was performed using tidal velocity data measured using both an Acoustic Doppler Velocimeter (ADV) and an Acoustic Doppler Current Profiler (ADCP) at the same location which allows for direct comparison of predictions. The extreme value analysis implements of a Peak-Over-Threshold method to explore the effect of perturbation length and time scale on the magnitude of a 50-year perturbation.

  4. Velocity determination of the very shallow lunar crust

    E-Print Network [OSTI]

    Yen, Tzuhua Edward

    1979-01-01T23:59:59.000Z

    , 1972 and 1974 ) for the Apollo 16 and 17 landing sites, respectively. A deep layer of dust on the moon may provide a very good seismic-wave transmission channel. In order to investigate the seismic properties of such a medium, Gold and Soter (1970...) at the Apollo 14 and 16 landing sites has been determined to be a self-compacting powder layer overlying a homogeneous layer. The velocity function of the powder layer is given by V(z)=V (z/z ) , where V =340+20 m/sec is a reference 1/6 0 0 0 velocity at a...

  5. Source shape determination with directional fragment-fragment velocity correlations

    E-Print Network [OSTI]

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

    2008-01-01T23:59:59.000Z

    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.

  6. Effect of the q-nonextensive electron velocity distribution on a magnetized plasma sheath

    SciTech Connect (OSTI)

    Safa, N. Navab, E-mail: n-navabsafa@sbu.ac.ir; Ghomi, H.; Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, Tehran 1983963113 (Iran, Islamic Republic of)

    2014-08-15T23:59:59.000Z

    In this work, a sheath model has been developed to investigate the effect of the q-nonextensive electron velocity distribution on the different characteristics of a magnetized plasma. By using Segdeev potential method, a modified Bohm criterion for a magnetized plasma with the nonextensive electron velocity distribution is derived. The sheath model is then used to analyze numerically the sheath structure under different q, the parameter quantifying the nonextensivity degree of the system. The results show that as the q-parameter decreases, the floating potential becomes more negative. The sheath length increases at the lower values of the q-parameter due to the increase in the electron population at the high-energy tail of the distribution function. As q-parameter decreases, the effective temperature of the electrons increases which results in a more extended plasma sheath. The ion velocity and density profiles for the different nonextensivity degrees of the system reflect the gyro-motion of the ions in the presence of the magnetic field. Furthermore, the results coincide with those given by the Maxwellian electron distribution function, when q tends to 1.

  7. A Terminal Velocity on the Landscape: Particle Production near Extra Species Loci in Higher Dimensions

    E-Print Network [OSTI]

    Diana Battefeld; Thorsten Battefeld

    2011-02-10T23:59:59.000Z

    We investigate particle production near extra species loci (ESL) in a higher dimensional field space and derive a speed limit in moduli space at weak coupling. This terminal velocity is set by the characteristic ESL-separation and the coupling of the extra degrees of freedom to the moduli, but it is independent of the moduli's potential if the dimensionality of the field space is considerably larger than the dimensionality of the loci, D >> d. Once the terminal velocity is approached, particles are produced at a plethora of nearby ESLs, preventing a further increase in speed via their backreaction. It is possible to drive inflation at the terminal velocity, providing a generalization of trapped inflation with attractive features: we find that more than sixty e-folds of inflation for sub-Planckian excursions in field space are possible if ESLs are ubiquitous, without fine tuning of initial conditions and less tuned potentials. We construct a simple, observationally viable model with a slightly red scalar power-spectrum and suppressed gravitational waves; we comment on the presence of additional observational signatures originating from IR-cascading and individual massive particles. We also show that moduli-trapping at an ESL is suppressed for D >> d, hindering dynamical selection of high-symmetry vacua on the landscape based on this mechanism.

  8. Isolating signatures of major cloud-cloud collisions using position-velocity diagrams

    E-Print Network [OSTI]

    Haworth, T J; Fukui, Y; Torii, K; Dale, J E; Shima, K; Takahira, K; Habe, A; Hasegawa, K

    2015-01-01T23:59:59.000Z

    Collisions between giant molecular clouds are a potential mechanism for triggering the formation of massive stars, or even super star clusters. The trouble is identifying this process observationally and distinguishing it from other mechanisms. We produce synthetic position-velocity diagrams from models of: cloud-cloud collisions, non-interacting clouds along the line of sight, clouds with internal radiative feedback and a more complex cloud evolving in a galactic disc, to try and identify unique signatures of collision. We find that a broad bridge feature connecting two intensity peaks, spatially correlated but separated in velocity, is a signature of a high velocity cloud-cloud collision. We show that the broad bridge feature is resilient to the effects of radiative feedback, at least to around 2.5Myr after the formation of the first massive (ionising) star. However for a head on 10km/s collision we find that this will only be observable from 20-30 per cent of viewing angles. Such broad-bridge features have...

  9. The Light Velocity Casimir Effect Does the Velocity of Light Increase when Propagating Between the Casimir Plates?

    E-Print Network [OSTI]

    Ostoma, T; Ostoma, Tom; Trushyk, Mike

    1999-01-01T23:59:59.000Z

    We propose experiments that might be set up to detect the increase in the velocity of light in a vacuum in the laboratory frame for photons travelling between (and perpendicular to) the Casimir plates in a vacuum. The Casimir plates are two closely spaced, conductive plates, where an attractive force is observed to exist between the plates called the 'Casimir Force'. We propose that the velocity of light in a vacuum increases when propagating between two transparent Casimir Plates. We call this effect the 'Light Velocity Casimir Effect' or LVC effect. The LVC effect happens because the vacuum energy density in between the plates is lower than that outside the Casimir plates. The conductive plates disallow certain frequencies of electrically charged virtual particles to exist inside the plates, thus lowering the inside vacuum particle density, compared to the density outside the plates. The reduced (electrically charged) virtual particle density results in fewer photon scattering events inside the plates, whic...

  10. Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 12518

    SciTech Connect (OSTI)

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy W.J.; Burns, Carolyn A.; Schonewill, Philip P.; Hopkins, Derek F. [Pacific Northwest National Laboratory, Richland, Washington 99354 (United States); Thien, Michael G.; Wooley, Theodore A. [Washington River Protection Solutions, Richland, Washington 99354 (United States)

    2012-07-01T23:59:59.000Z

    The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will be governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. In 2010 Washington River Protection Solutions and the Pacific Northwest National Laboratory began evaluating the ultrasonic PulseEcho instrument to accurately identify critical velocities in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of >50 micrometers. In 2011 the PulseEcho instrument was further evaluated to identify critical velocities for slurries containing fast-settling, high-density particles with a mean particle diameter of <15 micrometers. This two-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP. (authors)

  11. Investigation of plasma velocity field solar flare footpoints

    E-Print Network [OSTI]

    Mrozek, Tomasz

    of Wroclaw NCN Grant 2011/01/M/ST9/06096 #12;The Solar Flare - observations #12;chromosphere corona photosphere The Solar Flare - cartoon - conversion of magnetic energy into other forms - transport of energyInvestigation of plasma velocity field in solar flare footpoints from RHESSI observations T. Mrozek

  12. Scale-dependent seismic velocity in heterogeneous media

    SciTech Connect (OSTI)

    Mukerji, T.; Mavko, G.; Mujica, D. [Stanford Univ., CA (United States)] [Stanford Univ., CA (United States); Lucet, N. [IFP, Rueil-Malmaison (France)] [IFP, Rueil-Malmaison (France)

    1995-07-01T23:59:59.000Z

    The measurable traveltime of seismic events propagating in heterogeneous media depend on the geologic scale, the seismic wavelength, and the propagation distance. In general, the velocity inferred from arrival times is slower when the wavelength is longer than the scale of heterogeneity and faster when the wavelength is shorter. For normal incidence propagation in stratified media, this is the difference between averaging elastic compliance sin the long wavelength limit. In two and three dimensions there is also the path effect. Shorter wavelengths tend to find faster paths, thus biasing the traveltimes to lower values. In the shorter wavelength limit, the slowness inferred from the average traveltime is smaller than the mean slowness of the medium. When the propagation distance is much larger than the scale of the heterogeneity, the path effect causes the velocity increase from long to short wavelengths to be much larger in two dimensions than in one dimension, and even larger in three dimensions. The amount of velocity dispersion can be understood theoretically, but there is some discrepancy between theory and experiment as to what ratio of wavelength to heterogeneity scale separates the long and short wavelength limits. The scale-dependent traveltime implies that a measured velocity depends not just on rock properties, but also on the scale of the measurement relative to he scale of the geology.

  13. Velocity Autocorrelation Functions and Diffusion of Dusty Plasma

    SciTech Connect (OSTI)

    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

    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.

  14. Relativistic addition of parallel velocities from time dilation

    E-Print Network [OSTI]

    Bernhard Rothenstein; Stefan Popescu

    2006-08-11T23:59:59.000Z

    The relativistic addition of parallel velocities is derived involving relativity only via the time dilation formula, avoiding the length contraction used by many authors in conjunction with time dilation. The followed scenario involves a machine gun that fires successive bullets, considered from its rest frame and from the rest frame of the target, the bullets hit.

  15. VELOCITY FIELD OF A ROUND TURBULENT TRANSVERSE JET Suman Muppidi

    E-Print Network [OSTI]

    Mahesh, Krishnan

    - bulent jet in a laminar crossflow. The velocity ratio is 5.7 and the Reynolds number is 5000. Mean Jets in crossflow, also called `transverse jets' are defined as the flow field where a jet of fluid enters and interacts with a crossflowing fluid. Examples of jets in crossflow are fuel injectors

  16. Brady 1D seismic velocity model ambient noise prelim

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Mellors, Robert J.

    Preliminary 1D seismic velocity model derived from ambient noise correlation. 28 Green's functions filtered between 4-10 Hz for Vp, Vs, and Qs were calculated. 1D model estimated for each path. The final model is a median of the individual models. Resolution is best for the top 1 km. Poorly constrained with increasing depth.

  17. Harmonic analysis of the Ha velocity field of NGC 4254

    E-Print Network [OSTI]

    Laurent Chemin; Olivier Hernandez; Chantal Balkowski; Claude Carignan; Philippe Amram

    2005-12-20T23:59:59.000Z

    The ionized gas kinematics of the Virgo Cluster galaxy NGC 4254 (Messier 99) is analyzed by an harmonic decomposition of the velocity field into Fourier coefficients. The aims of this study are to measure the kinematical asymmetries of Virgo cluster galaxies and to connect them to the environment. The analysis reveals significant $m=1,2,4$ terms which origins are discussed.

  18. Brady 1D seismic velocity model ambient noise prelim

    SciTech Connect (OSTI)

    Mellors, Robert J.

    2013-10-25T23:59:59.000Z

    Preliminary 1D seismic velocity model derived from ambient noise correlation. 28 Green's functions filtered between 4-10 Hz for Vp, Vs, and Qs were calculated. 1D model estimated for each path. The final model is a median of the individual models. Resolution is best for the top 1 km. Poorly constrained with increasing depth.

  19. TOWARDS VERTICAL VELOCITY AND HYDROMETEOR CLASSIFICATION FROM ARM WIND PROFILERS

    E-Print Network [OSTI]

    - 98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscriptTOWARDS VERTICAL VELOCITY AND HYDROMETEOR CLASSIFICATION FROM ARM WIND PROFILERS Scott Giangrande Department/Atmospheric Sciences Division Brookhaven National Laboratory U.S. Department of Energy Office

  20. LAMINAR BURNING VELOCITY OF GASOLINES WITH ADDITION OF ETHANOL

    E-Print Network [OSTI]

    Boyer, Edmond

    1 LAMINAR BURNING VELOCITY OF GASOLINES WITH ADDITION OF ETHANOL P. Dirrenberger1 , P.A. Glaude*1 WITH ADDITION OF ETHANOL P. Dirrenberger1 , P.A. Glaude*1 , R. Bounaceur1 , H. Le Gall1 , A. Pires da Cruz2 , A. The influence of ethanol as an oxygenated additive has been investigated for these two fuels and has been found

  1. Low Velocity Sphere Impact of a Soda Lime Silicate Glass

    SciTech Connect (OSTI)

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

    2011-10-01T23:59:59.000Z

    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.

  2. Near-Surface Shear-Wave Velocity Measurements in Unlithified Sediment

    E-Print Network [OSTI]

    Rickards, Benjamin Thomas

    2011-05-31T23:59:59.000Z

    with an average S-wave velocity of 600 ft/sec in the top 30 meters as having a relatively high risk for amplifying destructive earthquake waves (Hunter et al., 2010). S-wave studies have also been used to identify subsidence and liquefaction risks for wind-turbine... the method is more challenging geometrically (Kanli, 2008). In fact, it has become common practice to run geological core samples through CAT scans to help determine composition and image bedforms for oil exploration (Stewart, 1991). Medical...

  3. On the Nature of the Radial Velocity Variability of Aldebaran: A Search for Spectral Line Bisector Variations

    E-Print Network [OSTI]

    Artie P. Hatzes; William D. Cochran

    1997-12-23T23:59:59.000Z

    The shape of the Ti I 6303.8 A spectral line of Aldebaran as measured by the line bisector was investigated using high signal-to-noise, high resolution data. The goal of this study was to understand the nature of the 643-day period in the radial velocity for this star reported by Hatzes and Cochran. Variations in the line bisector with the radial velocity period would provide strong evidence in support of rotational modulation or stellar pulsations as the cause of the 643-day period. A lack of any bisector variability at this period would support the planet hypothesis. Variations in the line asymmetries are found with a period of 49.93 days. These variations are uncorrelated with 643-day period found previously in the radial velocity measurements. It is demonstrated that this 50-day period is consistent with an m=4 nonradial sectoral g-mode oscillation. The lack of spectral variability with the radial velocity period of 643 days may provide strong evidence in support of the hypothesis that this variability stems from the reflex motion of the central star due to a planetary companion having a mass of 11 Jupiter masses. However, this long-period variability may still be due to a low order (m=2) pulsation mode since these would cause bisector variations less than the error measurement.

  4. The critical velocity in the BEC-BCS crossover

    E-Print Network [OSTI]

    Wolf Weimer; Kai Morgener; Vijay Pal Singh; Jonas Siegl; Klaus Hueck; Niclas Luick; Ludwig Mathey; Henning Moritz

    2014-08-22T23:59:59.000Z

    We map out the critical velocity in the crossover from Bose-Einstein condensation (BEC) to Bardeen-Cooper-Schrieffer superfluidity with ultracold $^{6}$Li gases. A small attractive potential is dragged along lines of constant column density. The rate of the induced heating increases steeply above a critical velocity $v_c$. In the same samples, we measure the speed of sound $v_s$ by exciting density waves and compare the results to the measured values of $v_c$. We perform numerical simulations in the BEC regime and find very good agreement, validating the approach. In the strongly correlated regime, where theoretical predictions only exist for the speed of sound, our measurements of $v_c$ provide a testing ground for theoretical approaches.

  5. Velocity tuning of friction with two trapped atoms

    E-Print Network [OSTI]

    Gangloff, Dorian; Counts, Ian; Jhe, Wonho; Vuleti?, Vladan

    2015-01-01T23:59:59.000Z

    Friction is the basic, ubiquitous mechanical interaction between two surfaces that results in resistance to motion and energy dissipation. In spite of its technological and economic significance, our ability to control friction remains modest, and our understanding of the microscopic processes incomplete. At the atomic scale, mismatch between the two contacting crystal lattices can lead to a reduction of stick-slip friction (structural lubricity), while thermally activated atomic motion can give rise to a complex velocity dependence, and nearly vanishing friction at sufficiently low velocities (thermal lubricity). Atomic force microscopy has provided a wealth of experimental results, but limitations in the dynamic range, time resolution, and control at the single-atom level have hampered a full quantitative description from first principles. Here, using an ion-crystal friction emulator with single-atom, single substrate-site spatial resolution and single-slip temporal resolution, we measure the friction force...

  6. The AMS-RICH velocity and charge reconstruction

    E-Print Network [OSTI]

    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

    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.

  7. Velocity renormalization in graphene from lattice Monte Carlo

    E-Print Network [OSTI]

    Joaquín E. Drut; Timo A. Lähde

    2014-03-26T23:59:59.000Z

    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. We find a renormalized Fermi velocity v_FR > v_F, where v_F = c/300. Our results are consistent with a momentum-independent v_FR which increases approximately linearly with alpha_g, although a logarithmic running with momentum cannot be excluded at present. At the predicted critical coupling alpha_gc for the semimetal-insulator transition due to excitonic pair formation, we find v_FR/v_F = 3.3, which we discuss in light of experimental findings for v_FR/v_F at the charge neutrality point in ultra-clean suspended graphene.

  8. Predicting stress-induced velocity anisotropy in rocks

    SciTech Connect (OSTI)

    Mavko, G.; Mukerji, T.; Godfrey, N. [Stanford Univ., CA (United States). Rock Physics Lab.] [Stanford Univ., CA (United States). Rock Physics Lab.

    1995-07-01T23:59:59.000Z

    A simple transformation, using measured isotropic V{sub P} and V{sub S} versus hydrostatic pressure, is presented for predicting stress-induced seismic velocity anisotropy in rocks. The compliant, crack-like portions of the pore space are characterized by generalized compressional and shear compliances that are estimated form the isotropic V{sub P} and V{sub S}. The physical assumption that the compliant porosity is crack-like means that the pressure dependence of the generalized compliances is governed primarily by normal tractions resolved across cracks and defects. This allows the measured pressure dependence to be mapped form the hydrostatic stress state to any applied nonhydrostatic stress. Predicted P- and S-wave velocities agree reasonably well with uniaxial stress data for Barre Granite and Massillon Sandstone. While it is mechanically similar to methods based on idealized ellipsoidal cracks, the approach is relatively independent of any assumed crack geometry and is not limited to small crack densities.

  9. Low velocity ion stopping in binary ionic mixtures

    SciTech Connect (OSTI)

    Tashev, Bekbolat; Baimbetov, Fazylkhan [Department of Physics, Kazakh National University, Tole Bi 96, Almaty 480012 (Kazakhstan); Deutsch, Claude [LPGP (UMR-CNRS 8578), Universite Paris XI, 91405 Orsay (France); Fromy, Patrice [Direction de l'Informatique, Universite Paris XI, 91405 Orsay (France)

    2008-10-15T23:59:59.000Z

    Attention is focused on the low ion velocity stopping mechanisms in multicomponent and dense target plasmas built of quasiclassical electron fluids neutralizing binary ionic mixtures, such as, deuterium-tritium of current fusion interest, proton-heliumlike iron in the solar interior or proton-helium ions considered in planetology, as well as other mixtures of fiducial concern in the heavy ion beam production of warm dense matter at Bragg peak conditions. The target plasma is taken in a multicomponent dielectric formulation a la Fried-Conte. The occurrence of projectile ion velocities (so-called critical) for which target electron slowing down equals that of given target ion components is also considered. The corresponding multiquadrature computations, albeit rather heavy, can be monitored analytical through a very compact code operating a PC cluster. Slowing down results are systematically scanned with respect to target temperature and electron density, as well as ion composition.

  10. Maximum velocity of self-propulsion for an active segment

    E-Print Network [OSTI]

    Recho, Pierre

    2015-01-01T23:59:59.000Z

    The motor part of a crawling eukaryotic cell can be represented schematically as an active continuum layer. The main active processes in this layer are protrusion, originating from non-equilibrium polymerization of actin fibers, contraction, induced by myosin molecular motors and attachment due to active bonding of trans-membrane proteins to a substrate. All three active mechanisms are regulated by complex signaling pathways involving chemical and mechanical feedback loops whose microscopic functioning is still poorly understood. In this situation, it is instructive to take a reverse engineering approach and study a problem of finding the spatial organization of standard active elements inside a crawling layer ensuring an optimal cost-performance trade-off. In this paper we assume that (in the range of interest) the energetic cost of self-propulsion is velocity independent and adopt, as an optimality criterion, the maximization of the overall velocity. We then choose a prototypical setting, formulate the corr...

  11. THE RADIAL VELOCITY EXPERIMENT (RAVE): FOURTH DATA RELEASE

    SciTech Connect (OSTI)

    Kordopatis, G.; Gilmore, G. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Steinmetz, M.; Williams, M. E. K.; Piffl, T.; Enke, H.; Carrillo, I. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Boeche, C.; Roeser, S. [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany); Seabroke, G. M. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Siebert, A. [Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l'Université, F-67000 Strasbourg (France); Zwitter, T. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Binney, J. [Rudolf Peierls Centre for Theoretical Physics, Keble Road, Oxford, OX1 3NP (United Kingdom); De Laverny, P.; Recio-Blanco, A.; Bijaoui, A. [Laboratoire Lagrange, UMR 7293, Université de Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur, BP4229, F-06304 Nice (France); Wyse, R. F. G. [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Freeman, K. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Munari, U. [INAF National Institute of Astrophysics, Astronomical Institute of Padova, I-36012 Asiago (VI) (Italy); Anguiano, B., E-mail: gkordo@ast.cam.ac.uk [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); and others

    2013-11-01T23:59:59.000Z

    We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances, and distances determined for 425,561 stars, which constitute the fourth public data release of the RAdial Velocity Experiment (RAVE). The stellar atmospheric parameters are computed using a new pipeline, based on the algorithms of MATISSE and DEGAS. The spectral degeneracies and the Two Micron All Sky Survey photometric information are now better taken into consideration, improving the parameter determination compared to the previous RAVE data releases. The individual abundances for six elements (magnesium, aluminum, silicon, titanium, iron, and nickel) are also given, based on a special-purpose pipeline that is also improved compared to that available for the RAVE DR3 and Chemical DR1 data releases. Together with photometric information and proper motions, these data can be retrieved from the RAVE collaboration Web site and the Vizier database.

  12. Astrometric determination of white dwarf radial velocities with Gaia?

    E-Print Network [OSTI]

    Jordan, Stefan

    2012-01-01T23:59:59.000Z

    Usually, the determination of radial velocities of stars relies on the shift of spectral lines by the Doppler effect. Russel & Atkinson (1931) and Oort (1932) already noted that due to the large proper motion and parallax of the white dwarf (WD) van Maanen 2, a determination of the perspective acceleration of the proper motion would provide a direct astrometric determination of the radial velocity which is independent of the gravitational redshift. If spectroscopic redshift measurements of Halpha and Hbeta NLTE cores exist, a purely astrometric determination would allow disentangling the gravitational redshift from the Doppler shift. The best instrument for measuring the tiny perspective acceleration is the Gaia satellite of the European Space Agency, aiming at absolute astrometric measurements of one billion stars down to 20th magnitude with unprecedented accuracy. At 15th magnitude, the predicted angular accuracy of Gaia is about 20 micro-arcseconds. In this article, we estimate whether it is possible t...

  13. Time, Distance, Velocity, Redshift: a personal guided tour

    E-Print Network [OSTI]

    T. Kiang

    2003-08-01T23:59:59.000Z

    An attempt to answer the question 'Can we observe galaxies that recede faster than light ?' led to a re-examination of the notions of time, distance, velocity and redshift as they occur in newtonian physics, special relativity, general relativity and cosmology. A number of misconceptions were uncovered. It was found that, once freed of special relativity preconceptions, the above question is easily and unequivocally answered

  14. Dynamic slip velocity correlation using non-spherical particles

    E-Print Network [OSTI]

    Pecore, Douglas Wilkin

    1990-01-01T23:59:59.000Z

    GRAMS FIGURE 39: FREQUENCY DISTRIBUTION, STATIC, MUD WEIGHT RANGE: 0. 5 - 0. 6 GRAMS FIGURE 40: FREQUENCY DISTRIBUTION, STATIC, MUD WEIGHT RANGE: 0. 6 - 0. 7 GRAMS FIGURE 41: FREQUENCY DISTRIBUTION, STATIC, MUD WEIGHT RANGE: 0. 7 - 0, 8 GRAMS... of Advisory Committee: Dr. Hans C. Juvkam-Wold This research proposes a method for calculating the slip velocity of irregularly shaped particles falling in non-Newtonian fluids in a vertical flow conduit under static and dynamic flow conditions. A...

  15. Obtaining anisotropic velocity data for proper depth seismic imaging

    SciTech Connect (OSTI)

    Egerev, Sergey; Yushin, Victor; Ovchinnikov, Oleg; Dubinsky, Vladimir; Patterson, Doug [Andreyev Acoustics Institute, Moscow, 117036 (Russian Federation); Baker Hughes, Inc, 2001 Rankin Road, Houston, TX, 77073 (United States)

    2012-05-24T23:59:59.000Z

    The paper deals with the problem of obtaining anisotropic velocity data due to continuous acoustic impedance-based measurements while scanning in the axial direction along the walls of the borehole. Diagrams of full conductivity of the piezoceramic transducer were used to derive anisotropy parameters of the rock sample. The measurements are aimed to support accurate depth imaging of seismic data. Understanding these common anisotropy effects is important when interpreting data where it is present.

  16. Radial Velocity Studies of Close Binary Stars. XI

    E-Print Network [OSTI]

    Theodor Pribulla; Slavek M. Rucinski; Wenxian Lu; Stefan W. Mochnacki; George Conidis; R. M. Blake; Heide DeBond; J. R. Thomson; Wojtek Pych; Waldemar Ogloza; Michal Siwak

    2006-05-15T23:59:59.000Z

    Radial-velocity measurements and sine-curve fits to the orbital radial velocity variations are presented for ten close binary systems: DU Boo, ET Boo, TX Cnc, V1073 Cyg, HL Dra, AK Her, VW LMi, V566 Oph, TV UMi and AG Vir. By this contribution, the DDO program has reached the point of 100 published radial velocity orbits. The radial velocities have been determined using an improved fitting technique which uses rotational profiles to approximate individual peaks in broadening functions. Three systems, ET Boo, VW LMi and TV UMi, were found to be quadruple while AG Vir appears to be a spectroscopic triple. ET Boo, a member of a close visual binary with $P_{vis} = 113$ years, was previously known to be a multiple system, but we show that the second component is actually a close, non-eclipsing binary. The new observations enabled us to determine the spectroscopic orbits of the companion, non-eclipsing pairs in ET Boo and VW LMi. The particularly interesting case is VW LMi, where the period of the mutual revolution of the two spectroscopic binaries is only 355 days. While most of the studied eclipsing pairs are contact binaries, ET Boo is composed of two double-lined detached binaries and HL Dra is single-lined detached or semi-detached system. Five systems of this group were observed spectroscopically before: TX Cnc, V1073 Cyg, AK Her (as a single-lined binary), V566 Oph, AG Vir, but our new data are of much higher quality than the previous studies.

  17. RVSAO 2.0: Digital Redshifts and Radial Velocities

    E-Print Network [OSTI]

    Michael J. Kurtz; Douglas J. Mink

    1998-03-25T23:59:59.000Z

    RVSAO is a set of programs to obtain redshifts and radial velocities from digital spectra. RVSAO operates in the IRAF(Tody 1986, 1993) environment. The heart of the system is xcsao, which implements the cross-correlation method, and is a direct descendant of the system built by Tonry and Davis (1979). emsao uses intelligent heuristics to search for emission lines in spectra, then fits them to obtain a redshift. sumspec shifts and sums spectra to build templates for cross-correlation. linespec builds synthetic spectra given a list of spectral lines. bcvcorr corrects velocities for the motion of the earth. We discuss in detail the parameters necessary to run xcsao and emsao properly. We discuss the reliability and error associated with xcsao derived redshifts. We develop an internal error estimator, and we show how large, stable surveys can be used to develop more accurate error estimators. We develop a new methodology for building spectral templates for galaxy redshifts. We show how to obtain correlation velocities using emission line templates. Emission line correlations are substantially more efficient than the previous standard technique, automated emission line fitting. We compare the use of RVSAO with new methods, which use Singular Value Decomposition and $\\chi^2$ fitting techniques.

  18. Multiprocessor position/velocity servo control for multiaxis digital robot control system

    SciTech Connect (OSTI)

    Lancraft, R.E.; Daggett, K.E.; Omaga, E.M.; Casler, R.J. Jr.; Booth, B.L.; Bergman, N.J.; Nuncy, M.D.

    1989-09-19T23:59:59.000Z

    This paper describes a digitally controlled robot. It comprises: an arm having a plurality of joints; each of the joints being axis driven by an electric motor drive; a power amplifier operable to supply drive current to each joint drive motor; respective feedback control loop means for respectively controlling the power amplifier for each of the joint drive motors; servo control means for performing control support tasks and calculation tasks; control means including a first microprocessor having a relatively high computing performance capability and a relatively low data processing interface capability; control means further including a second microprocessor having a relatively high data processing performance capability; means for interfacing the first and second microprocessors; means for generating position commands for implementation by the second microprocessor; means for detecting motor position and velocity for each drive axis and for generating corresponding digital feedback signals; means for operating the second microprocessor to control the interfacing means so as to send position commands to the first microprocessor and receive calculated torque commands from the first microprocessor; and means for operating the second microprocessor to apply the torque commands to the torque control circuitry for execution and for synchronously receiving from the motor detecting means the digital feedback position and velocity signals.

  19. THE ROCKSTAR PHASE-SPACE TEMPORAL HALO FINDER AND THE VELOCITY OFFSETS OF CLUSTER CORES

    SciTech Connect (OSTI)

    Behroozi, Peter S.; Wechsler, Risa H.; Wu, Hao-Yi [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA 94305 (United States)] [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA 94305 (United States)

    2013-01-10T23:59:59.000Z

    We present a new algorithm for identifying dark matter halos, substructure, and tidal features. The approach is based on adaptive hierarchical refinement of friends-of-friends groups in six phase-space dimensions and one time dimension, which allows for robust (grid-independent, shape-independent, and noise-resilient) tracking of substructure; as such, it is named ROCKSTAR (Robust Overdensity Calculation using K-Space Topologically Adaptive Refinement). Our method is massively parallel (up to 10{sup 5} CPUs) and runs on the largest current simulations (>10{sup 10} particles) with high efficiency (10 CPU hours and 60 gigabytes of memory required per billion particles analyzed). A previous paper has shown ROCKSTAR to have excellent recovery of halo properties; we expand on these comparisons with more tests and higher-resolution simulations. We show a significant improvement in substructure recovery compared to several other halo finders and discuss the theoretical and practical limits of simulations in this regard. Finally, we present results that demonstrate conclusively that dark matter halo cores are not at rest relative to the halo bulk or substructure average velocities and have coherent velocity offsets across a wide range of halo masses and redshifts. For massive clusters, these offsets can be up to 350 km s{sup -1} at z = 0 and even higher at high redshifts. Our implementation is publicly available at http://code.google.com/p/rockstar.

  20. Spectroscopic measurement of ion temperature and ion velocity distributions in the flux-coil generated FRC

    SciTech Connect (OSTI)

    Gupta, D.; Gota, H.; Hayashi, R.; Kiyashko, V.; Morehouse, M.; Primavera, S. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States); Bolte, N. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States); Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Marsili, P. [Department of Physics, University of Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Roche, T. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Wessel, F. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

    2010-10-15T23:59:59.000Z

    One aim of the flux-coil generated field reversed configuration at Tri Alpha Energy (TAE) is to establish the plasma where the ion rotational energy is greater than the ion thermal energy. To verify this, an optical diagnostic was developed to simultaneously measure the Doppler velocity-shift and line-broadening using a 0.75 m, 1800 groves/mm, spectrometer. The output spectrum is magnified and imaged onto a 16-channel photomultiplier tube (PMT) array. The individual PMT outputs are coupled to high-gain, high-frequency, transimpedance amplifiers, providing fast-time response. The Doppler spectroscopy measurements, along with a survey spectrometer and photodiode-light detector, form a suite of diagnostics that provide insights into the time evolution of the plasma-ion distribution and current when accelerated by an azimuthal-electric field.

  1. An approach to improving transporting velocity in the long-range ultrasonic transportation of micro-particles

    SciTech Connect (OSTI)

    Meng, Jianxin; Mei, Deqing, E-mail: meidq-127@zju.edu.cn; Yang, Keji; Fan, Zongwei [State Key Lab of Fluid Power Transmission and Control, Department of Mechanical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China)

    2014-08-14T23:59:59.000Z

    In existing ultrasonic transportation methods, the long-range transportation of micro-particles is always realized in step-by-step way. Due to the substantial decrease of the driving force in each step, the transportation is lower-speed and stair-stepping. To improve the transporting velocity, a non-stepping ultrasonic transportation approach is proposed. By quantitatively analyzing the acoustic potential well, an optimal region is defined as the position, where the largest driving force is provided under the condition that the driving force is simultaneously the major component of an acoustic radiation force. To keep the micro-particle trapped in the optimal region during the whole transportation process, an approach of optimizing the phase-shifting velocity and phase-shifting step is adopted. Due to the stable and large driving force, the displacement of the micro-particle is an approximately linear function of time, instead of a stair-stepping function of time as in the existing step-by-step methods. An experimental setup is also developed to validate this approach. Long-range ultrasonic transportations of zirconium beads with high transporting velocity were realized. The experimental results demonstrated that this approach is an effective way to improve transporting velocity in the long-range ultrasonic transportation of micro-particles.

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

    SciTech Connect (OSTI)

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

    2012-01-10T23:59:59.000Z

    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.

  3. The pre-merger impact velocity of the binary cluster A1750 from X-ray, lensing, and hydrodynamical simulations

    SciTech Connect (OSTI)

    Molnar, Sandor M. [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China); Chiu, I-Non Tim [Department of Physics, Ludwig-Maximilians University, Scheinerstr 1, D-81679 Munich (Germany); Broadhurst, Tom [Department of Theoretical Physics, University of the Basque Country, E-48080 Bilbao (Spain); Stadel, Joachim G., E-mail: sandor@phys.ntu.edu.tw [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland)

    2013-12-10T23:59:59.000Z

    Since the discovery of the 'Bullet Cluster', several similar cases have been uncovered that suggest relative velocities well beyond the tail of high speed collisions predicted by the concordance ?CDM model. However, quantifying such post-merger events with hydrodynamical models requires a wide coverage of possible initial conditions. Here, we show that it is simpler to interpret pre-merger cases, such as A1750, where the gas between the colliding clusters is modestly affected, so that the initial conditions are clear. We analyze publicly available Chandra data confirming a significant increase in the projected X-ray temperature between the two cluster centers in A1750 consistent with our expectations for a merging cluster. We model this system with a self-consistent hydrodynamical simulation of dark matter and gas using the FLASH code. Our simulations reproduce well the X-ray data and the measured redshift difference between the two clusters in the phase before the first core passage viewed at an intermediate projection angle. The deprojected initial relative velocity derived using our model is 1460 km s{sup –1}, which is considerably higher than the predicted mean impact velocity for simulated massive haloes derived by recent ?CDM cosmological simulations, but is within the allowed range. Our simulations demonstrate that such systems can be identified using a multi-wavelength approach and numerical simulations, for which the statistical distribution of relative impact velocities may provide a definitive examination of a broad range of dark matter scenarios.

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

    E-Print Network [OSTI]

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

    2007-03-14T23:59:59.000Z

    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.

  5. High brightness electron accelerator

    DOE Patents [OSTI]

    Sheffield, Richard L. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM); Young, Lloyd M. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    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 electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  6. Low Velocity Sphere Impact of a Borosilicate Glass

    SciTech Connect (OSTI)

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

    2012-05-01T23:59:59.000Z

    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.

  7. Cloud-Scale Vertical Velocity and Turbulent Dissipation Rate Retrievals

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Shupe, Matthew

    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 2008). These time periods will be expanded in a future submission.

  8. Method and apparatus for measuring flow velocity using matched filters

    DOE Patents [OSTI]

    Raptis, Apostolos C. (Downers Grove, IL)

    1983-01-01T23:59:59.000Z

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. 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.

  9. Method and apparatus for measuring flow velocity using matched filters

    DOE Patents [OSTI]

    Raptis, A.C.

    1983-09-06T23:59:59.000Z

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. 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. 8 figs.

  10. Velocity bunching in travelling wave accelerator with low acceleration gradient

    E-Print Network [OSTI]

    Huang, Rui-Xuan; Li, Wei-Wei; Jia, Qi-Ka

    2013-01-01T23:59:59.000Z

    We present the analytical and simulated results concerning the influences of the acceleration gradient in the velocity bunching process, which is a bunch compression scheme that uses a traveling wave accelerating structure as a compressor. Our study shows that the bunch compression application with low acceleration gradient is more tolerant to phase jitter and more successful to obtain compressed electron beam with symmetrical longitudinal distribution and low energy spread. We also present a transverse emittance compensation scheme to compensate the emittance growth caused by the increasing of the space charge force in the compressing process that is easy to be adjusted for different compressing factors.

  11. Accounting for velocity jitter in planet search surveys

    E-Print Network [OSTI]

    Roman V. Baluev

    2008-11-08T23:59:59.000Z

    The role of radial velocity (RV) jitter in extrasolar planet search surveys is discussed. Based on the maximum likelihood principle, improved statistical algorithms for RV fitting and period search are developed. These algorithms incorporate a built-in jitter determination, so that resulting estimations of planetary parameters account for this jitter automatically. This approach is applied to RV data for several extrasolar planetary systems. It is shown that many RV planet search surveys suffer from periodic systematic errors which increase effective RV jitter and can lead to erroneous conclusions. For instance, the planet candidate HD74156 d may be a false detection made due to annual systematic errors.

  12. A method of measuring velocity of sound in soil samples

    E-Print Network [OSTI]

    Matzen, Walter T

    1950-01-01T23:59:59.000Z

    , 0% feet per second. In the brass bar: (Figure 11) g ? $. 71 feet h = 2?300 cycles v = 10, 8% feet per second . 20 ?l6 0 ' ISO Q I8o q ISO 0 ISO 0 ISO PHASE SHIFT L8 DEGREE Figure 10. Helation of, Frequejncy to Phase Shift iri steel . 'Tuhe.... '28 26 20 18 16 0 leO P IBo 0 . ' l80: 0, ' ']80, 0 iS'o pigure' ll. Relation of Frequee'cg, to Pha'ss Shift; iri Brass 'Bar. 1 Again, the velocity in brass, given by Carlin as 14. , 500 feet per second, is a reasonable check. In the aluminum...

  13. The oceanic and cratonic upper mantle: Clues from joint interpretation of global velocity and attenuation models

    E-Print Network [OSTI]

    Asthenosphere Seismic attenuation Seismic velocity Anelasticity Partial melt Combined interpretation of seismicThe oceanic and cratonic upper mantle: Clues from joint interpretation of global velocity anelastic dispersion (Karato and Jung, 1998; Karato, 2003). A unique interpretation of seismological models

  14. Brady Geothermal 1D seismic velocity model - Datasets - OpenEI...

    Open Energy Info (EERE)

    1025. Number is 262. Title is "Brady 1D seismic velocity http:geothermaldata.orgdatasetbrady-1d-seismic-velocity-model-ambient-noise-prelim-prelim-brady-median-vpvsqs-model...

  15. Evidence for a critical velocity in a Bose-Einstein condensed gas

    E-Print Network [OSTI]

    C. Raman; M. Kohl; R. Onofrio; D. S. Durfee; C. E. Kuklewicz; Z. Hadzibabic; W. Ketterle

    1999-09-07T23:59:59.000Z

    We have studied dissipation in a Bose--Einstein condensed gas by moving a blue detuned laser beam through the condensate at different velocities. Strong heating was observed only above a critical velocity.

  16. Understanding the dynamical structure of pulsating stars: The center-of-mass velocity and the Baade-Wesselink projection factor of the beta-Cephei star alpha-Lupi

    E-Print Network [OSTI]

    Nardetto, N; Fokin, A; Chapellier, E; Pietrzynski, G; Gieren, W; Graczyk, D; Mourard, D

    2013-01-01T23:59:59.000Z

    High-resolution spectroscopy of pulsating stars is a powerful tool to study the dynamical structure of their atmosphere. Lines asymmetry is used to derive the center-of-mass velocity of the star, while a direct measurement of the atmospheric velocity gradient helps determine the projection factor used in the Baade-Wesselink method of distance determination. We aim at deriving the center-of-mass velocity and the projection factor of the beta-Cephei star alpha-Lup. We present HARPS high spectral resolution observations of alpha-Lup. We calculate the first-moment radial velocities and fit the spectral line profiles by a bi-Gaussian to derive line asymmetries. Correlations between the gamma-velocity and the gamma-asymmetry (defined as the average values of the radial velocity and line asymmetry curves respectively) are used to derive the center-of-mass velocity of the star. By combining our spectroscopic determination of the atmospheric velocity gradient with a hydrodynamical modelof the photosphere of the star, ...

  17. Holographic and time-resolving ability of pulse-pair two-dimensional velocity interferometry

    SciTech Connect (OSTI)

    Erskine, David J., E-mail: erskine1@llnl.gov; Smith, R. F.; Celliers, P. M.; Collins, G. W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Bolme, C. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ali, S. J. [Department of Chemistry, University of California, Berkeley, California 94720 (United States)

    2014-06-15T23:59:59.000Z

    Previous velocity interferometers used at research laboratories for shock physics experiments measured target motion at a point or many points on a line on the target. Recently, a two-dimensional (2d) version (2d-velocity interferometer system for any reflector) has been demonstrated using a pair of ultrashort (3 ps) pulses for illumination, separated by 268 ps. We have discovered new abilities for this instrument, by treating the complex output image as a hologram. For data taken in an out of focus configuration, we can Fourier process to bring narrow features such as cracks into sharp focus, which are otherwise completely blurred. This solves a practical problem when using high numerical aperture optics having narrow depth of field to observe moving surface features such as cracks. Furthermore, theory predicts that the target appearance (position and reflectivity) at two separate moments in time are recorded by the main and conjugate images of the same hologram, and are partially separable during analysis for narrow features. Hence, for the cracks we bring into refocus, we can make a two-frame movie with a subnanosecond frame period. Longer and shorter frame periods are possible with different interferometer delays. Since the megapixel optical detectors we use have superior spatial resolution over electronic beam based framing cameras, this technology could be of great use in studying microscopic three-dimensional-behavior of targets at ultrafast times scales. Demonstrations on shocked silicon are shown.

  18. Extensional wave attenuation and velocity in partially saturated sand in the sonic frequency range

    SciTech Connect (OSTI)

    Liu, Z.; Rector, J.W.; Nihei, K.T.; Tomutsa, L.; Myer, L.R.; Nakagawa, S.

    2001-08-10T23:59:59.000Z

    Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1-9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (Q{sub E} dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.

  19. Real-time planar flow velocity measurements using an optical flow algorithm implemented on GPU

    E-Print Network [OSTI]

    Gautier, N

    2013-01-01T23:59:59.000Z

    This paper presents a high speed implementation of an optical flow algorithm which computes planar velocity fields in an experimental flow. Real-time computation of the flow velocity field allows the experimentalist to have instantaneous access to quantitative features of the flow. This can be very useful in many situations: fast evaluation of the performances and characteristics of a new setup, design optimization, easier and faster parametric studies, etc. It can also be a valuable measurement tool for closed-loop flow control experiments where fast estimation of the state of the flow is needed. The algorithm is implemented on a Graphics Processing Unit (GPU). The accuracy of the computation is shown. Computation speed and scalability are highlighted along with guidelines for further improvements. The system architecture is flexible, scalable and can be adapted on the fly in order to process higher resolutions or achieve higher precision. The set-up is applied on a Backward-Facing Step (BFS) flow in a hydro...

  20. Characterization of Vertical Velocity and Drop Size Distribution Parameters in Widespread Precipitation at ARM Facilities

    SciTech Connect (OSTI)

    Giangrande S. E.; Luke, E. P.; Kollias, P.

    2012-02-01T23:59:59.000Z

    Extended, high-resolution measurements of vertical air motion and median volume drop diameter D0 in widespread precipitation from three diverse Atmospheric Radiation Measurement Program (ARM) locations [Lamont, Oklahoma, Southern Great Plains site (SGP); Niamey, Niger; and Black Forest, Germany] are presented. The analysis indicates a weak (0-10 cm{sup -1}) downward air motion beneath the melting layer for all three regions, a magnitude that is to within the typical uncertainty of the retrieval methods. On average, the hourly estimated standard deviation of the vertical air motion is 0.25 m s{sup -1} with no pronounced vertical structure. Profiles of D0 vary according to region and rainfall rate. The standard deviation of 1-min-averaged D0 profiles for isolated rainfall rate intervals is 0.3-0.4 mm. Additional insights into the form of the raindrop size distribution are provided using available dual-frequency Doppler velocity observations at SGP. The analysis suggests that gamma functions better explain paired velocity observations and radar retrievals for the Oklahoma dataset. This study will be useful in assessing uncertainties introduced in the measurement of precipitation parameters from ground-based and spaceborne remote sensors that are due to small-scale variability.

  1. Velocity dispersion and upscaling in a laboratory-simulated VSP

    SciTech Connect (OSTI)

    Rio, P.; Mukerji, T.; Mavko, G. [Stanford Univ., CA (United States)] [Stanford Univ., CA (United States); Marion, D. [Elf Aquitaine, Pau (France)] [Elf Aquitaine, Pau (France)

    1996-03-01T23:59:59.000Z

    A laboratory and numerical study was conducted to investigate the impact of scale-dependent seismic wave propagation in randomly layered media, as applied to sonic logs, surface seismic, and vertical seismic profiles (VSPs). Analysis of the laboratory results (1) confirmed the wavelength dependence of velocities inferred from traveltimes, (2) indicated that scale effects can introduce traveltime errors when upscaling from logs to surface seismic and VSPs, and (3) illustrated that erroneous VSP interval velocities can result when layer thicknesses are smaller than about one-tenth of the wavelength. A simple approximate recipe is presented for estimating these traveltimes by successively filtering the medium using a running Backus average and ray theory. The scale-dependent dispersion was also predicted well using a more rigorous invariant imbedding formulation. The predicted traveltimes, using the approximate recipe, compare well with the times observed in the laboratory stack of steel and plastic layers and in numerical studies of stratified media. The dispersion curves predicted by the approximate method also show the overall behavior computed with the more rigorous invariant imbedding formulation.

  2. Cosmic density and velocity fields in Lagrangian perturbation theory

    E-Print Network [OSTI]

    Mikel Susperregi; Thomas Buchert

    1997-08-04T23:59:59.000Z

    A first- and second-order relation between cosmic density and peculiar-velocity fields is presented. The calculation is purely Lagrangian and it is derived using the second-order solutions of the Lagrange-Newton system obtained by Buchert & Ehlers. The procedure is applied to two particular solutions given generic initial conditions. In this approach, the continuity equation yields a relation between the over-density and peculiar-velocity fields that automatically satisfies Euler's equation because the orbits are derived from the Lagrange-Newton system. This scheme generalizes some results obtained by Nusser et al. (1991) in the context of the Zel'dovich approximation. As opposed to several other reconstruction schemes, in this approach it is not necessary to truncate the expansion of the Jacobian given by the continuity equation in order to calculate a first- or second-order expression for the density field. In these previous schemes, the density contrast given by (a) the continuity equation and (b) Euler's equation are mutually incompatible. This inconsistency arises as a consequence of an improper handling of Lagrangian and Eulerian coordinates in the analysis. Here, we take into account the fact that an exact calculation of the density is feasible in the Lagrangian picture and therefore an accurate and consistent description is obtained.

  3. Measurements of parallel electron velocity distributions using whistler wave absorption

    SciTech Connect (OSTI)

    Thuecks, D. J.; Skiff, F.; Kletzing, C. A. [Department of Physics and Astronomy, University of Iowa, 203 Van Allen Hall, Iowa City, Iowa 52242 (United States)

    2012-08-15T23:59:59.000Z

    We describe a diagnostic to measure the parallel electron velocity distribution in a magnetized plasma that is overdense ({omega}{sub pe} > {omega}{sub ce}). This technique utilizes resonant absorption of whistler waves by electrons with velocities parallel to a background magnetic field. The whistler waves were launched and received by a pair of dipole antennas immersed in a cylindrical discharge plasma at two positions along an axial background magnetic field. The whistler wave frequency was swept from somewhat below and up to the electron cyclotron frequency {omega}{sub ce}. As the frequency was swept, the wave was resonantly absorbed by the part of the electron phase space density which was Doppler shifted into resonance according to the relation {omega}-k{sub ||v||} = {omega}{sub ce}. The measured absorption is directly related to the reduced parallel electron distribution function integrated along the wave trajectory. The background theory and initial results from this diagnostic are presented here. Though this diagnostic is best suited to detect tail populations of the parallel electron distribution function, these first results show that this diagnostic is also rather successful in measuring the bulk plasma density and temperature both during the plasma discharge and into the afterglow.

  4. Tracking deep mantle reservoirs with ultra-low velocity zones Allen K. McNamara a,

    E-Print Network [OSTI]

    Rhoads, James

    Tracking deep mantle reservoirs with ultra-low velocity zones Allen K. McNamara a, , Edward J, that directly overlies the core-mantle boundary (CMB). These regions have been dubbed Ultra-Low Velocity Zones. Introduction For over 15 yrs seismologists have mapped regions of ultra-low P- and S-wave velocities

  5. Ultra-low velocities and Superplumes Garnero, Thorne, McNamara, Rost [2005

    E-Print Network [OSTI]

    Garnero, Ed

    Ultra-low velocities and Superplumes Garnero, Thorne, McNamara, Rost [2005] - 1- Fine-scale ultra-low, Arizona 85287-1404 USA Abstract. Ultra-low velocity layering at Earth's core-mantle boundary has now been in the overlying few hundred km of the mantle. Ultra-low velocity zones contain properties consistent with partial

  6. Investigation of the Moessbauer Spectrum Quality as a Dependence on the Frequency of the Velocity Signal

    SciTech Connect (OSTI)

    Pechousek, J. [Centre for Nanomaterial Research, Faculty of Science, Palacky University, Slechtitelu 11, 783 71, Olomouc (Czech Republic); Department of Experimental Physics, Faculty of Science, Palacky University, 17, listopadu 1192/12, 771 46, Olomouc (Czech Republic); Prochazka, R.; Cuda, J.; Frydrych, J.; Jancik, D. [Centre for Nanomaterial Research, Faculty of Science, Palacky University, Slechtitelu 11, 783 71, Olomouc (Czech Republic)

    2010-07-13T23:59:59.000Z

    This paper is focused on a quality characterizing the Moessbauer spectra measured for various frequencies of the velocity signal. Standard electromechanical double-loudspeaker drive and digital PID velocity controller were used for calibration spectra measurement in the frequency interval from 4 up to 100 Hz. Several parameters were evaluated for recommendation of the suitable velocity signal frequency.

  7. Experimental investigation of burning velocities of ultra-wet methane-air-steam mixtures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , steam, burning velocity, chemiluminescence, OH Introduction In ultra-wet gas turbines, the heatExperimental investigation of burning velocities of ultra-wet methane-air-steam mixtures Eric Abstract Global burning velocities of methane-air-steam mixtures are measured on prismatic laminar Bunsen

  8. Microbial Activity during Biodegradation and its Effects on Groundwater Velocity in a Contaminated Aquifer

    E-Print Network [OSTI]

    Schillig, Peter Curtis

    2008-03-26T23:59:59.000Z

    of Contents??????????????????????????vi List of Tables???????????????????????????...ix List of Figures???????????????????????????...x Chapter 1: Introduction...??????????????????????...1 1.1: The Importance of Groundwater Velocity.............................................??1 1.2: Impact of Biological Activity on Groundwater Velocity...??????2 1.3: Current Techniques for Determining Groundwater Velocity...????..2 1.3.1: Indirect Techniques???...?????????????...3 1.3.2: Direct Techniques...

  9. 3D Least Squares Velocity from 3D Doppler Radial X. Chen, J.L. Barron, R.E. Mercer

    E-Print Network [OSTI]

    Barron, John

    neighbourhoods to compute local 3D velocity. Radial velocity (measured by the Doppler effect) is the component3D Least Squares Velocity from 3D Doppler Radial Velocity X. Chen, J.L. Barron, R.E. Mercer Dept. Radial velocity can be used to predict the motion of storms in sequences of Doppler radar datasets

  10. activated combustion-high velocity: Topics by E-print Network

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

    (arXiv) Summary: We compare the zonal flow pattern in subsurface layers of the Sun with the distribution of surface magnetic features like sunspots and polar faculae. We...

  11. Telescopio Nazionale Galileo Instrumentation High Accuracy Radial velocity Planet Searcher for the Northern

    E-Print Network [OSTI]

    .49 4308.37 0.011733 23 16 4314.62 - 4363.21 4338.92 0.011820 24 17 4345.43 - 4394.37 4369.90 0.011904 25

  12. An insitu borescopic quantitative imaging profiler for the measurement of high concentration sediment velocity

    E-Print Network [OSTI]

    Cowen, Edwin A.; Dudley, Russell D.; Liao, Qian; Variano, Evan A.; Liu, Philip L.-F.

    2010-01-01T23:59:59.000Z

    applied to oscillatory boundary layer ?ow over a porous bed.of sand in oscillatory boundary-layers. Coast Eng 25:205–225

  13. Modeling and Control of High-Velocity Oxygen-Fuel (HVOF) Thermal Spray: A Tutorial Review

    E-Print Network [OSTI]

    Li, Mingheng; Christofides, Panagiotis D.

    2009-01-01T23:59:59.000Z

    2700 (Sulzer Metco, Westbury, NY) and the Praxair-TafaJP-5000 (Praxair Surface Technolo- gies, Indianapolis, IN)),pro- cessing using a Praxair-TAFA JP-5000 HVOF thermal spray

  14. Measurement and modelling of high-resolution flow-velocity data under simulated rainfall on a

    E-Print Network [OSTI]

    solves the Saint- Venant equations in 2D, MAHLERAN uses a 1D kinematic wave in the slope direction 0022 in revised form 5 July 2007; accepted 23 July 2007 KEYWORDS Rainfall-simulation; Water erosion; Erosion algorithm that is close in principle to the diffusion-wave equation in 2D. The Darcy­ Weisbach friction

  15. Modeling and Control of High-Velocity Oxygen-Fuel (HVOF) Thermal Spray: A Tutorial Review

    E-Print Network [OSTI]

    Li, Mingheng; Christofides, Panagiotis D.

    2009-01-01T23:59:59.000Z

    Size Distribution in Aerosol Processes with Simulta- neous Reaction, Nucleation, Condensation and Coagulation,

  16. An insitu borescopic quantitative imaging profiler for the measurement of high concentration sediment velocity

    E-Print Network [OSTI]

    Cowen, Edwin A.; Dudley, Russell D.; Liao, Qian; Variano, Evan A.; Liu, Philip L.-F.

    2010-01-01T23:59:59.000Z

    the smallest Re, a Karman vortex street is expected with afrequency of the Karman vortex street does not show up.

  17. Horizontal-Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Yelena L.; Banta, Robert M.; Kelley, Neil D.; Jonkman, Bonnie J.; Tucker, Sara C.; Newsom, Rob K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--has been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA’s High Resolution Doppler Lidar (HRDL), which have been shown to be numerically equivalent to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance ?u2 were computed from HRDL measurements of the line-of-sight (LOS) velocity using a technique described in Banta, et al. (2002). The technique was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. It then describes several series of averaging tests that produced the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal velocity variance ?u2. The results show high correlation (0.71-0.97) of the mean U and average wind speed measured by sodar and in-situ instruments, independent of sampling strategies and averaging procedures. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging techniques.

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

    SciTech Connect (OSTI)

    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

    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.

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

    SciTech Connect (OSTI)

    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

    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.

  20. The effect of rainfall on the velocity distribution in shallow channel flow

    E-Print Network [OSTI]

    Glass, Larry Joe

    1965-01-01T23:59:59.000Z

    , gave the following equation for uniform two-dimensional open channel f low v v max ~2. Iog y Ve~~ in which v is the velocity at any distance, y, above the channel bed, v Is the maximum velocity, g is the acceleration of gravity, d is the Illa X... piezometer located at the same longi- tudinal position along the flume at the tip of the ve'locity probe. The velocity coefficient of the total head probe was obtained by two methods. 29 One method was determining the velocity by observing the time...

  1. Particle in cell simulations of Buneman instability of a current-driven plasma with q-nonextensive electron velocity distribution

    SciTech Connect (OSTI)

    Niknam, A. R., E-mail: a-niknam@sbu.ac.ir; Roozbahani, H.; Komaizi, D. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Hashemzadeh, M. [Faculty of Physics, Shahrood University, Shahrood (Iran, Islamic Republic of)

    2014-09-15T23:59:59.000Z

    The nonlinear evolution of low frequency Buneman instability in an unmagnetized current-driven plasma with q-nonextensive electron velocity distribution is investigated using particle in cell simulation. Simulation results show that the generation of electron phase space holes and the counter-streaming current induced in the plasma strongly depend on the q-parameter. It is found that by increasing the nonextensive parameter, the distribution of electron density becomes highly peaked. This density steepening or grating-like pattern occurs at the saturation time. In addition, a generalized dispersion relation is obtained using the kinetic theory. Analysis of the dispersion relation and the temporal evolution of the electric field energy density reveal that the growth rate of instability increases by increasing the q-parameter. Finally, the results of Maxwellian and q-nonextensive velocity distributions have been compared and discussed.

  2. Acoustic velocity measurements in materials using a regenerative method

    DOE Patents [OSTI]

    Laine, Edwin F. (Alamo, CA)

    1986-01-01T23:59:59.000Z

    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.

  3. Acoustic-velocity measurements in materials using a regenerative method

    DOE Patents [OSTI]

    Laine, E.F.

    1982-09-30T23:59:59.000Z

    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.

  4. Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs

    E-Print Network [OSTI]

    G. Michalek; N. Gopalswamy; S. Yashiro

    2008-01-13T23:59:59.000Z

    Halo coronal mass ejections (HCMEs) originating from regions close to the center of the Sun are likely to be responsible for severe geomagnetic storms. It is important to predict geo-effectiveness of HCMEs using observations when they are still near the Sun. Unfortunately, coronagraphic observations do not provide true speeds of CMEs due to the projection effects. In the present paper, we present a new technique allowing estimate the space speed and approximate source location using projected speeds measured at different position angles for a given HCME (velocity asymmetry). We apply this technique to HCMEs observed during 2001-2002 and find that the improved speeds are better correlated with the travel times of HCMEs to Earth and with the magnitudes ensuing geomagnetic storms.

  5. A numerical study of geometry dependent errors in velocity, temperature, and density measurements from single grid planar retarding potential analyzers

    SciTech Connect (OSTI)

    Davidson, R. L.; Earle, G. D.; Heelis, R. A. [William B. Hanson Center for Space Sciences, University of Texas at Dallas, 800 W. Campbell Road, WT15, Richardson, Texas 75080 (United States); Klenzing, J. H. [Space Weather Laboratory/Code 674, Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)

    2010-08-15T23:59:59.000Z

    Planar retarding potential analyzers (RPAs) have been utilized numerous times on high profile missions such as the Communications/Navigation Outage Forecast System and the Defense Meteorological Satellite Program to measure plasma composition, temperature, density, and the velocity component perpendicular to the plane of the instrument aperture. These instruments use biased grids to approximate ideal biased planes. These grids introduce perturbations in the electric potential distribution inside the instrument and when unaccounted for cause errors in the measured plasma parameters. Traditionally, the grids utilized in RPAs have been made of fine wires woven into a mesh. Previous studies on the errors caused by grids in RPAs have approximated woven grids with a truly flat grid. Using a commercial ion optics software package, errors in inferred parameters caused by both woven and flat grids are examined. A flat grid geometry shows the smallest temperature and density errors, while the double thick flat grid displays minimal errors for velocities over the temperature and velocity range used. Wire thickness along the dominant flow direction is found to be a critical design parameter in regard to errors in all three inferred plasma parameters. The results shown for each case provide valuable design guidelines for future RPA development.

  6. CALIBRATING STELLAR VELOCITY DISPERSIONS BASED ON SPATIALLY RESOLVED H-BAND SPECTRA FOR IMPROVING THE M{sub BH}-{sigma}{sub *} RELATION

    SciTech Connect (OSTI)

    Kang, Wol-Rang; Woo, Jong-Hak; Park, Daeseong [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro Gwanak-gu, Seoul, 151-742 (Korea, Republic of)] [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro Gwanak-gu, Seoul, 151-742 (Korea, Republic of); Schulze, Andreas [Kavli Institute for Astronomy and Astrophysics, Peking University, 100871 Beijing (China)] [Kavli Institute for Astronomy and Astrophysics, Peking University, 100871 Beijing (China); Riechers, Dominik A. [Astronomy Department, Cornell University, 220 Space Science Building, Ithaca, NY 14853 (United States)] [Astronomy Department, Cornell University, 220 Space Science Building, Ithaca, NY 14853 (United States); Kim, Sang Chul [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)] [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Smolcic, Vernesa, E-mail: woo@astro.snu.ac.kr [Physics Department, University of Zagreb, Bijenicka cesta 32, 10002 Zagreb (Croatia)] [Physics Department, University of Zagreb, Bijenicka cesta 32, 10002 Zagreb (Croatia)

    2013-04-10T23:59:59.000Z

    To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (M{sub BH})-stellar velocity dispersion ({sigma}{sub *}) relation, we measure {sigma}{sub *} based on high-quality H-band spectra for a sample of 31 nearby galaxies, for which dynamical M{sub BH} is available in the literature. By comparing velocity dispersions measured from stellar lines in the H-band with those measured from optical stellar lines, we find no significant difference, suggesting that optical and near-IR stellar lines represent the same kinematics and that dust effect is negligible for early-type galaxies. Based on the spatially resolved rotation and velocity dispersion measurements along the major axis of each galaxy, we find that a rotating stellar disk is present for 80% of galaxies in the sample. For galaxies with a rotation component, {sigma}{sub *} measured from a single aperture spectrum can vary by up to {approx}20%, depending on the size of the adopted extraction aperture. To correct for the rotational broadening, we derive luminosity-weighted {sigma}{sub *} within the effective radius of each galaxy, providing uniformly measured velocity dispersions to improve the M{sub BH}-{sigma}{sub *} relation.

  7. Impact of boundaries on velocity profiles in bubble rafts

    E-Print Network [OSTI]

    Yuhong Wang; Kapilanjan Krishan; Michael Dennin

    2006-01-31T23:59:59.000Z

    Under conditions of sufficiently slow flow, foams, colloids, granular matter, and various pastes have been observed to exhibit shear localization, i.e. regions of flow coexisting with regions of solid-like behavior. The details of such shear localization can vary depending on the system being studied. A number of the systems of interest are confined so as to be quasi-two dimensional, and an important issue in these systems is the role of the confining boundaries. For foams, three basic systems have been studied with very different boundary conditions: Hele-Shaw cells (bubbles confined between two solid plates); bubble rafts (a single layer of bubbles freely floating on a surface of water); and confined bubble rafts (bubbles confined between the surface of water below and a glass plate on top). Often, it is assumed that the impact of the boundaries is not significant in the ``quasi-static limit'', i.e. when externally imposed rates of strain are sufficiently smaller than internal kinematic relaxation times. In this paper, we directly test this assumption for rates of strain ranging from $10^{-3}$ to $10^{-2} {\\rm s^{-1}}$. This corresponds to the quoted quasi-static limit in a number of previous experiments. It is found that the top plate dramatically alters both the velocity profile and the distribution of nonlinear rearrangements, even at these slow rates of strain.

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

    E-Print Network [OSTI]

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

    2008-01-01T23:59:59.000Z

    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.

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

    SciTech Connect (OSTI)

    Arnold, P. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))

    1993-08-15T23:59:59.000Z

    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. I demonstrate 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 ( thin-wall'') limit.

  10. Effect of turbulent velocity on the \\HI intensity fluctuation power spectrum from spiral galaxies

    E-Print Network [OSTI]

    Dutta, Prasun

    2015-01-01T23:59:59.000Z

    We use numerical simulations to investigate effect of turbulent velocity on the power spectrum of \\HI intensity from external galaxies when (a) all emission is considered, (b) emission with velocity range smaller than the turbulent velocity dispersion is considered. We found that for case (a) the intensity fluctuation depends directly only on the power spectrum of the column density, whereas for case (b) it depends only on the turbulent velocity fluctuation. We discuss the implications of this result in real observations of \\HI fluctuations.

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

    Open Energy Info (EERE)

    search OpenEI Reference LibraryAdd to library Journal Article: Three-dimensional P and S waves velocity structures of the Coso geothermal area, California, from...

  12. Test Loop Demonstration and Evaluation of Slurry Transfer Line Critical Velocity Measurement Instruments

    SciTech Connect (OSTI)

    Bontha, Jagannadha R.; Jenks, Jeromy WJ; Morgen, Gerald P.; Peters, Timothy J.; Wilcox, Wayne A.; Adkins, Harold E.; Burns, Carolyn A.; Greenwood, Margaret S.; MacFarlan, Paul J.; Denslow, Kayte M.; Schonewill, Philip P.; Blanchard, Jeremy; Baer, Ellen BK

    2010-07-31T23:59:59.000Z

    This report presents the results of the evaluation of three ultrasonic sensors for detecting critical velocity during slurry transfer between the Hanford tank farms and the WTP.

  13. asymmetric m-b velocity: Topics by E-print Network

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

    Consistent with Asymmetric M-B Velocity Distributions-Implications on Direct Dark Matter Searches General Relativity & Quantum Cosmology (arXiv) Summary: In the present paper...

  14. A new P-velocity model for the Tethyan margin from a scaled S-velocity model and the inversion of P-and PKP-delay times

    E-Print Network [OSTI]

    van der Lee, Suzan

    A new P-velocity model for the Tethyan margin from a scaled S-velocity model and the inversion of P- and PKP-delay times Sung-Joon Chang a, , Suzan Van der Lee a , Megan P. Flanagan b a Dept. of Earth Livermore National Laboratory, P.O. Box 808, L-205, Livermore, CA 94551, USA a r t i c l e i n f o Article

  15. Horizontal Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Y. L.; Banta, R. M.; Kelley, N. D.; Jonkman, B. J.; Tucker, S. C.; Newsom, R. K.; Brewer, W. A.

    2008-08-01T23:59:59.000Z

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--have been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA's high-resolution Doppler lidar (HRDL), which have been shown to be approximately equal to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance {sigma}2u were computed from HRDL measurements of the line-of-sight (LOS) velocity using a method described by Banta et al., which uses an elevation (vertical slice) scanning technique. The method was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. The results for the mean U and mean wind speed measured by sodar and in situ instruments for all nights of LLLJP show high correlation (0.71-0.97), independent of sampling strategies and averaging procedures, and correlation coefficients consistently >0.9 for four high-wind nights, when the low-level jet speeds exceeded 15 m s{sup -1} at some time during the night. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging parameters. Several series of averaging tests are described, to find the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal-velocity variance {sigma}{sup 2}{sub u}. Because of the nonstationarity of the SBL data, the best results were obtained when the velocity data were first averaged over intervals of 1 min, and then further averaged over 3-15 consecutive 1-min intervals, with best results for the 10- and 15-min averaging periods. For these cases, correlation coefficients exceeded 0.9. As a part of the analysis, Eulerian integral time scales ({tau}) were estimated for the four high-wind nights. Time series of {tau} through each night indicated erratic behavior consistent with the nonstationarity. Histograms of {tau} showed a mode at 4-5 s, but frequent occurrences of larger {tau} values, mostly between 10 and 100 s.

  16. Electromagnetic plane waves with negative phase velocity in charged black strings

    SciTech Connect (OSTI)

    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

    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.

  17. The Effect of Slip Velocity on Saturation for Multiphase Condensing Mixtures in a PEM Fuel Cell

    E-Print Network [OSTI]

    Stockie, John

    The Effect of Slip Velocity on Saturation for Multiphase Condensing Mixtures in a PEM Fuel Cell in computed results reported in the fuel cell literature, but which has not yet received a satisfactory to treat the slip velocity between phases. Keywords: Condensation ­ Two Phase Flow ­ PEM Fuel Cell ­ Slip

  18. The equivalence principle and the relative velocity of local inertial frames

    E-Print Network [OSTI]

    F. Shojai; A. Shojai

    2015-05-25T23:59:59.000Z

    In this paper we explicitly show that in general relativity, the relative velocity of two local inertial frames is always less than the velocity of light. This fact is a by-product of the equivalence principle. The general result is then illustrated within two examples, the FLRW cosmological model and the Schwarzschild metric.

  19. Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity.

    E-Print Network [OSTI]

    Simpkins, Alex

    Coulomb Friction Viscous Friction Stribeck Friction Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity. Static Friction Model: Friction force opposes the direction of motion when the sliding velocity is zero. Coulomb Friction Model: Friction force

  20. ccsd00000648 Damping rates of the atomic velocity in Sisyphus cooling

    E-Print Network [OSTI]

    decades have witnessed an impressive progress in laser cooling techniques, and nowdays it is possibleccsd­00000648 (version 1) : 29 Sep 2003 Damping rates of the atomic velocity in Sisyphus cooling and experimental study of the damping process of the atomic velocity in Sisyphus cooling. The relaxation rates

  1. Arctic sea ice velocity field: General circulation and turbulent-like fluctuations

    E-Print Network [OSTI]

    Boyer, Edmond

    Arctic sea ice velocity field: General circulation and turbulent-like fluctuations P. Rampal,1,2 J the Arctic sea ice velocity field as the superposition of a mean field and fluctuations. We study how subtracting the mean field, are analyzed in terms of diffusion properties. Although the Arctic sea ice cover

  2. Sound velocities of ferropericlase in the Earth's lower mantle Jung-Fu Lin,1

    E-Print Network [OSTI]

    Lin, Jung-Fu "Afu"

    . Introduction [2] The speed of seismic waves in the Earth's lower mantle is governed by the elastic properties a dramatic increase in the isothermal bulk modulus (KT) and bulk sound velocity (VF) at the electronic spinSound velocities of ferropericlase in the Earth's lower mantle Jung-Fu Lin,1 Steven D. Jacobsen,2

  3. Measurement of fast-changing low velocities by photonic Doppler velocimetry

    SciTech Connect (OSTI)

    Song Hongwei; Wu Xianqian; Huang Chenguang; Wei Yangpeng; Wang Xi [Key Laboratory for Hydrodynamics and Ocean Engineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-07-15T23:59:59.000Z

    Despite the increasing popularity of photonic Doppler velocimetry (PDV) in shock wave experiments, its capability of capturing low particle velocities while changing rapidly is still questionable. The paper discusses the performance of short time Fourier transform (STFT) and continuous wavelet transform (CWT) in processing fringe signals of fast-changing low velocities measured by PDV. Two typical experiments are carried out to evaluate the performance. In the laser shock peening test, the CWT gives a better interpretation to the free surface velocity history, where the elastic precursor, main plastic wave, and elastic release wave can be clearly identified. The velocities of stress waves, Hugoniot elastic limit, and the amplitude of shock pressure induced by laser can be obtained from the measurement. In the Kolsky-bar based tests, both methods show validity of processing the longitudinal velocity signal of incident bar, whereas CWT improperly interprets the radial velocity of the shocked sample at the beginning period, indicating the sensitiveness of the CWT to the background noise. STFT is relatively robust in extracting waveforms of low signal-to-noise ratio. Data processing method greatly affects the temporal resolution and velocity resolution of a given fringe signal, usually CWT demonstrates a better local temporal resolution and velocity resolution, due to its adaptability to the local frequency, also due to the finer time-frequency product according to the uncertainty principle.

  4. Radial velocities of three poorly studied clusters and the kinematics of open clusters

    SciTech Connect (OSTI)

    Hayes, Christian R.; Friel, Eileen D., E-mail: hayescr@indiana.edu, E-mail: efriel@indiana.edu [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States)

    2014-04-01T23:59:59.000Z

    We present radial velocities for stars in the field of the open star clusters Berkeley 44, Berkeley 81, and NGC 6802 from spectra obtained using the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5 m telescope. These clusters are of intermediate age (1-3 Gyr), located within the solar Galactocentric radius, and have no previous radial velocity measurements. We find mean radial velocities of –9.6 ± 3.0 km s{sup –1}, 48.1 ± 2.0 km s{sup –1}, and 12.4 ± 2.8 km s{sup –1} for Be 44, Be 81, and NGC 6802, respectively. We present an analysis of radial velocities of 134 open clusters of a wide range of ages using data obtained in this study and the literature. Assuming the system of clusters rotates about the Galactic center with a constant velocity, we find older clusters exhibit a slower rotation and larger line-of-sight (LOS) velocity dispersion than younger clusters. The gradual decrease in rotational velocity of the cluster system with age is accompanied by a smooth increase in LOS velocity dispersion, which we interpret as the effect of heating on the open cluster system over time.

  5. Particle Temperature and Velocity Effects on the Porosity and Oxidation of an HVOF

    E-Print Network [OSTI]

    Settles, Gary S.

    Particle Temperature and Velocity Effects on the Porosity and Oxidation of an HVOF Corrosion) Independent control of particle velocity and temperature in the HVOF process has been achieved on porosity and no effect on oxidation. Particle temperature, on the other hand, correlates strongly

  6. Interferometric velocity analysis using physical and nonphysical energy Simon King1

    E-Print Network [OSTI]

    Interferometric velocity analysis using physical and nonphysical energy Simon King1 , Andrew Curtis as apparent energy that could not have propagated between receiver locations -- so-called nonphysical energy. We have developed a novel method of velocity analysis that uses both the physical and nonphysical

  7. Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method

    SciTech Connect (OSTI)

    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

    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.

  8. The Systemic Velocity and Internal Kinematics of the Dwarf Galaxy LGS 3: An Optical Foray beyond the Milky Way

    SciTech Connect (OSTI)

    Cook, K.H. [Lawrence Livermore National Lab, Lab Experimental Astrophysics, MS L-401, P.O. Box 808, Livermore, CA 94550 (United States)] [Lawrence Livermore National Lab, Lab Experimental Astrophysics, MS L-401, P.O. Box 808, Livermore, CA 94550 (United States); Mateo, M. [Department of Astronomy, University of Michigan, 821 Dennison Building, Ann Arbor, MI 48109--1090 (United States)] [Department of Astronomy, University of Michigan, 821 Dennison Building, Ann Arbor, MI 48109--1090 (United States); Olszewski, E.W. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)] [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Vogt, S.S. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)] [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Stubbs, C.; Diercks, A. [Department of Astronomy, FM-20, University of Washington, Seattle, WA 98195 (United States)] [Department of Astronomy, FM-20, University of Washington, Seattle, WA 98195 (United States)

    1999-03-01T23:59:59.000Z

    We have obtained radial velocities of three K giants and one faint carbon star in LGS 3, a dwarf companion of M31, based on 12 individual spectra obtained with the HIRES spectrograph on the Keck I telescope. The mean precision of these measurements is 3.8 km s{sup {minus}1}. The mean systemic velocity of LGS 3 is {minus}282.2{plus_minus}3.5 km s{sup {minus}1}. Monte Carlo simulations that take into account the individual velocity uncertainties and the maximum observed velocity difference reveal that the central velocity dispersion of LGS 3 is in the range 2.6{endash}30.5 km s{sup {minus}1}, with 95{percent} confidence; the most likely value for the central dispersion is 7.9{sup {plus}5.3} {sub {minus}2.9} km s{sup {minus}1}. These results agree with the kinematics of H i gas in LGS 3. This contrasts with the tendency for the gas and stars in other low-luminosity Local Group dwarfs to exhibit distinct spatial and kinematic properties. Taking into account the relative youth of LGS 3, we conclude that the {open_quotes}asymptotic{close_quotes} M/L ratio{emdash}the value the galaxy would exhibit if it were composed only of ancient stars{emdash}is M/L{sub V,LGS3} {ge}11 (at a 97.5{percent} confidence level), with a most probable value of 95{sup {plus}175} {sub {minus}56}. These values are consistent with the M/L{sub V} ratios observed in other well-studied early-type dwarfs of the Local Group. We have also estimated the mass of LGS 3 using modified Newtonian dynamics. These data represent the first moderately high precision optical spectra of giants in a dwarf system beyond the Galactic halo. We suggest future studies that are now feasible to study the dynamics of dwarf galaxies throughout the Local Group and beyond. {copyright} {ital {copyright} 1999.} {ital The Astronomical Society of the Pacific}

  9. Effects of Velocity Correlation on Early Stage of Free Cooling Process of Inelastic Hard Sphere System

    E-Print Network [OSTI]

    Ryo Kawahara; Hiizu Nakanishi

    2003-10-29T23:59:59.000Z

    The free cooling process in the inelastic hard sphere system is studied by analysing the data from large scale molecular dynamics simulations on a three dimensional system. The initial energy decay, the velocity distribution function, and the velocity correlation functions are calculated to be compared with theoretical predictions. The energy decay rate in the homogeneous cooling state is slightly but distinctively smaller than that expected from the independent collision assumption. The form of the one particle velocity distribution is found not to be stationary. These contradict to the predictions of the kinetic theory based on the Enskog-Boltzmann equation and suggest that the velocity correlation is already important in the early stage of homogeneous cooling state. The energy decay rate is analysed in terms of the velocity correlation.

  10. Derivation of Relativistic law of Addition of Velocities from Superposition of Eigenfunctions and Discreteness

    E-Print Network [OSTI]

    Mushfiq Ahmad

    2007-08-20T23:59:59.000Z

    We have defined a slowness, s, as the reciprocal conjugate of velocity, v. s = -ih/v. We have shown that Einstein's postulate (v has an upper limit) implies that s is discrete. A velocity operator is defined as the derivative with respect to s. Superposition of corresponding Eigenfunctions give Galilean law of addition of velocities. We have replaced the differential operator by the corresponding finite difference symmetric operator. We have shown that superposition of corresponding discrete Eigenfunctions give relativistic law of addition of velocities. A reciprocal symmetric number system is developed and with the help of this number system we have shown the relation between superposition and relativistic law of addition of velocities.

  11. Line formation in AGB atmospheres including velocity effects. Molecular line profile variations of long period variables

    E-Print Network [OSTI]

    Nowotny, W; Aringer, B

    2010-01-01T23:59:59.000Z

    The atmospheres of evolved red giants are considerably influenced by pulsations of the stellar interiors and developing stellar winds. The resulting complex velocity fields severely affect molecular line profiles observable in NIR spectra. With the help of model calculations the complex line formation process in AGB atmospheres was explored with the focus on velocity effects. Furthermore, we aimed for atmospheric models which are able to quantitatively reproduce line profile variations found in observed spectra of pulsating late-type giants. Models describing pulsation-enhanced dust-driven winds were used to compute synthetic spectra under the assumptions of chemical equilibrium and LTE and by solving the radiative transfer in spherical geometry including velocity effects. Radial velocities derived from Doppler-shifted synthetic line profiles provide information on the gas velocities in the line-forming region of the spectral features. On the basis of dynamic models we investigated in detail the finding that ...

  12. Thin liquid lithium targets for high power density

    E-Print Network [OSTI]

    McDonald, Kirk

    High charge state High velocity flow ~60 m/s High heat capacity of Li Absorbs power depositedThin liquid lithium targets for high power density applications: heavy ion beam strippers and beta Hilton Malmö City #12;Outline Liquid Lithium Stripper idea for FRIB Brief theory of film stability

  13. Transition scenario of the round jet in crossflow topology at low velocity ratios

    E-Print Network [OSTI]

    Cambonie, Tristan

    2014-01-01T23:59:59.000Z

    We study experimentally a round Jet In CrossFlow (JICF) at low values of the jet to-crossflow velocity ratio R using instantaneous and time-averaged three-dimensions three-components (3D3C) velocimetry. The difference between instantaneous and time-averaged swirling structures of the JICF is emphasized. Through the analysis of spatial distribution of instantaneous transverse and longitudinal vortices the main transitions of the JICF are characterized for 0.15 1.25), the classic JICF topology is recovered. In between, a deformation of the classical JICF topology is observed consisting in a progressive disappearance of the leading-edge vortices, a bending of the jet trajectory and thus a strengthened interaction with the boundary layer. toward the wall. Thanks to a state-of-the-art review on the JICF topology and using visualizations of the flow structures extracted from our experimental volumetric velocimetry measurements, this article provides a complete transition scenario of the JICF topology from the high...

  14. Anomalous fluctuations of vertical velocity of Earth and their possible implications for earthquakes

    SciTech Connect (OSTI)

    Manshour, Pouya [Department of Physics, Sharif University of Technology, Tehran 11155-9161 (Iran, Islamic Republic of); Ghasemi, Fatemeh; Sahimi, Muhammad [Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211 (United States); Matsumoto, T. [Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502 (Japan); CNRS UMR 6202, Observatoire de la Cote d'Azur, BP 4229, 06304 Nice Cedex 4 (France); Gomez, J. [Earth Sciences Department, University of Zaragoza, Zaragoza 50009 (Spain); Peinke, J. [Institute of Physics, Carl von Ossietzky University, D-26111 Oldenburg (Germany); Pacheco, A. F. [Department of Theoretical Physics, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Tabar, M. Reza Rahimi [Department of Physics, Sharif University of Technology, Tehran 11155-9161 (Iran, Islamic Republic of); CNRS UMR 6202, Observatoire de la Cote d'Azur, BP 4229, 06304 Nice Cedex 4 (France); Institute of Physics, Carl von Ossietzky University, D-26111 Oldenburg (Germany); Fachbereich Physik, Universitaet Osnabrueck, Barbarastrasse, 49706 Osnabrueck (Germany)

    2010-09-15T23:59:59.000Z

    High-quality measurements of seismic activities around the world provide a wealth of data and information that are relevant to understanding of when earthquakes may occur. If viewed as complex stochastic time series, such data may be analyzed by methods that provide deeper insights into their nature, hence leading to better understanding of the data and their possible implications for earthquakes. In this paper, we provide further evidence for our recent proposal [P. Mansour et al., Phys. Rev. Lett. 102, 014101 (2009)] for the existence of a transition in the shape of the probability density function (PDF) of the successive detrended increments of the stochastic fluctuations of Earth's vertical velocity V{sub z}, collected by broadband stations before moderate and large earthquakes. To demonstrate the transition, we carried out extensive analysis of the data for V{sub z} for 12 earthquakes in several regions around the world, including the recent catasrophic one in Haiti. The analysis supports the hypothesis that before and near the time of an earthquake, the shape of the PDF undergoes significant and discernable changes, which can be characterized quantitatively. The typical time over which the PDF undergoes the transition is about 5-10 h prior to a moderate or large earthquake.

  15. Discovery of an Unbound Hyper-Velocity Star in the Milky Way Halo

    E-Print Network [OSTI]

    Warren R. Brown; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz

    2005-01-11T23:59:59.000Z

    We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of +853+-12 km/s, the largest velocity ever observed in the Milky Way halo. The star is either a hot blue horizontal branch star or a B9 main sequence star with a heliocentric distance ~55 kpc. Corrected for the solar reflex motion and to the local standard of rest, the Galactic rest-frame velocity is +709 km/s. Because its radial velocity vector points 173.8 deg from the Galactic center, we suggest that this star is the first example of a hyper-velocity star ejected from the Galactic center as predicted by Hills and later discussed by Yu & Tremaine. The star has [Fe/H]~0, consistent with a Galactic center origin, and a travel time of <80 Myr from the Galactic center, consistent with its stellar lifetime. If the star is indeed traveling from the Galactic center, it should have a proper motion of 0.3 mas/yr observable with GAIA. Identifying additional hyper-velocity stars throughout the halo will constrain the production rate history of hyper-velocity stars at the Galactic center.

  16. Constitutive Theory for Velocity Dispersion in Rock with Dual Porosity

    SciTech Connect (OSTI)

    Wang, H F; Berryman, J G

    2002-03-28T23:59:59.000Z

    The high frequency behavior of the bulk modulus of fluid-saturated rock can be obtained from a double-porosity constitutive model, which is a direct conceptual extension of Biot's (1941) constitutive equations and which provides additional stiffening due to unrelaxed induced pore pressures in the soft porosity phase. Modeling the stiffening of the shear modulus at high frequency requires an effective medium average over the unequal induced pore pressures in cracks of different orientations. The implicit assumptions are that pore fluid equilibration does not occur between cracks of different orientations and between cracks and porous matrix. The correspondence between the constitutive equations of Berryman and Wang (1995) and Mavko and Jizba (1991) is explicitly noted.

  17. Velocity selection of ultra-cold atoms with Fabry-Perot laser devices: improvements and limits

    E-Print Network [OSTI]

    A. Ruschhaupt; F. Delgado; J. G. Muga

    2005-02-28T23:59:59.000Z

    We discuss a method to select the velocities of ultra-cold atoms with a modified Fabry-Perot type of device made of two effective barriers and a well created, respectively, by blue and red detuned lasers. The laser parameters may be used to select the peak and width of the transmitted velocity window. In particular, lowering the central well provides a peak arbitrarily close to zero velocity having a minimum but finite width. The low-energy atomic scattering off this laser device is parameterized and approximate formulae are found to describe and explain its behaviour.

  18. Design of regulated velocity flow assurance device for petroleum industry

    E-Print Network [OSTI]

    Yardi, Chaitanya Narendra

    2005-02-17T23:59:59.000Z

    are magnified in the offshore oil industry as the subsea temperatures are not high enough to prevent the precipitation of these waxes. The removal of these deposits is done by a variety of means, either by injection of chemicals which help in dissolution... and distilled products, are the lifeline of the United States of America. Since a major part of these pipelines were either subsea or underground and 8 hence the removal of these deposits had to be done from inside the pipeline. Assuring and maintaining flow...

  19. Ring diagram analysis of velocity fields within the solar convection zone

    E-Print Network [OSTI]

    Sarbani Basu; H. M. Antia; S. C. Tripathy

    1998-06-23T23:59:59.000Z

    Ring diagram analysis of solar oscillation power spectra obtained from MDI data is performed to study the velocity fields within the solar convection zone. The three dimensional power spectra are fitted to a model with a Lorentzian profile in frequency and includes the advection of the wave front by horizontal flows to obtain the two horizontal components of flows as a function of the horizontal wave number and radial order of the oscillation modes. This information is then inverted using the OLA and RLS techniques to infer the variation in flow velocity with depth. The resulting velocity fields yield the mean rotation velocity at different latitudes which agrees reasonably with helioseismic estimates. The zonal flow inferred in the outermost layers also appears to be in agreement with other measurements. A meridional flow from equator polewards is found to have an amplitude of about 25 m/s near the surface and the amplitude appears to increase with depth.

  20. Influence of Shelves on Air Temperature and Velocity in a Supermarket

    E-Print Network [OSTI]

    Song, C.; Fang, X.; Tan, Y.

    2006-01-01T23:59:59.000Z

    will be great. According to the analysis of measurement results of a supermarket in Harbin, factors such as relative position of supply and return air inlets, height of shelves and objects with heat generating capabilities influence the velocity fields...

  1. Radiation reaction 4-force: orthogonal or parallel to the 4-velocity?

    E-Print Network [OSTI]

    Calin Galeriu

    2001-08-30T23:59:59.000Z

    In this note we point to some problems related to the standard derivation of the radiation reaction 4-force, and we propose a new expression for this 4-force, parallel to the 4-velocity.

  2. Full wavefield inversion methods for monitoring time-lapse subsurface velocity changes

    E-Print Network [OSTI]

    Yang, Di, Ph. D. Massachusetts Institute of Technology

    2014-01-01T23:59:59.000Z

    Quantitative measurements of seismic velocity changes from time-lapse seismic experiments provide dynamic information about the subsurface that improves the understanding of the geology and reservoir properties. In this ...

  3. Radial Velocity Curves of Ellipsoidal Red Giant Binaries in the Large Magellanic Cloud

    E-Print Network [OSTI]

    Nie, J D

    2015-01-01T23:59:59.000Z

    Ellipsoidal red giant binaries are close binary systems where an unseen, relatively close companion distorts the red giant, leading to light variations as the red giant moves around its orbit. These binaries are likely to be the immediate evolutionary precursors of close binary planetary nebula and post-asymptotic giant branch and post-red giant branch stars. Due to the MACHO and OGLE photometric monitoring projects, the light variability nature of these ellipsoidal variables has been well studied. However, due to the lack of radial velocity curves, the nature of their masses, separations, and other orbital details has so far remained largely unknown. In order to improve this situation, we have carried out spectral monitoring observations of a large sample of 80 ellipsoidal variables in the Large Magellanic Cloud and we have derived radial velocity curves. At least 12 radial velocity points with good quality were obtained for most of the ellipsoidal variables. The radial velocity data are provided with this p...

  4. Estimating attitude and wind velocity using biomimetic sensors on a microrobotic bee

    E-Print Network [OSTI]

    Fuller, Sawyer Buckminster

    to estimate attitude angle relative to a luminous sky. We demonstrate accurate wind velocity estimation have three light sensors, distinct from the compound eyes, that point roughly upward and sense the sky

  5. A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma

    E-Print Network [OSTI]

    Ohta, Shigemi

    A Summary of Convective-Core Vertical Velocity Properties Using ARM UHF Wind Profilers in Oklahoma Sciences Division, Argonne National Laboratory, Argonne, Illinois # University of Oklahoma, Norman, Oklahoma @ Bureau of Meteorology, Melbourne, Victoria, Australia & Cooperative Institute for Research

  6. TRANSPORT PROPERTIES OF A CHAIN OF ANHARMONIC OSCILLATORS WITH RANDOM FLIP OF VELOCITIES

    E-Print Network [OSTI]

    TRANSPORT PROPERTIES OF A CHAIN OF ANHARMONIC OSCILLATORS WITH RANDOM FLIP OF VELOCITIES C into the hot reservoir, but it is impossible to extract energy for the cold reservoir. In other wo

  7. Diffusion in random velocity fields with applications to contaminant transport in groundwater

    E-Print Network [OSTI]

    Suciu, Nicolae

    Diffusion in random velocity fields with applications to contaminant transport in groundwater is the mathematical object underlying cur- rently used stochastic models of transport in groundwater. The essential: Groundwater, Transport processes, Ergodicity, Random fields, Random walk, PDF methods 1. Introduction

  8. Simultaneous and instantaneous measurement of velocity and density in rayleigh-taylor mixing layers

    E-Print Network [OSTI]

    Kraft, Wayne Neal

    2009-05-15T23:59:59.000Z

    -driven turbulence in a statistically steady gas channel of helium and air ( 6 . 0 03 . 0 ? ? t A ). The capability of the diagnostic to simultaneously and instantaneously measure turbulent velocity and density fluctuations allows for a unique investigation...

  9. The development of a low velocity wind tunnel with instrumentation for boundary layer investigations

    E-Print Network [OSTI]

    Massey, John Robert

    1958-01-01T23:59:59.000Z

    . Complete leakage tests were made, and the leaks so detected were sealed with Glyptal. Though closing the leaks greatly improved the results, unacceptable differences remained in velocity measure? 45 ments. For example, the recorder continued to have...

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

    Open Energy Info (EERE)

    geothermal area Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Teleseismic evidence for a low-velocity body under the Coso geothermal area...

  11. The Development of an Accuracy of a Doppler Global System for One Dimensional Velocity Measurement

    E-Print Network [OSTI]

    Karabacak, Mustafa

    2014-05-23T23:59:59.000Z

    shifting of the light frequency reflected by seeded particles or rotating disc surface speed. The relationship between the Doppler shift and the transmission ratio is a key part of the DGV system to calculate measured velocity. The absorption line filter...

  12. 3-D seismic velocity and attenuation structures in the geothermal field

    SciTech Connect (OSTI)

    Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

    2013-09-09T23:59:59.000Z

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  13. The effect of velocity and porosity profiles on the performance of fixed bed reactors

    E-Print Network [OSTI]

    Amin, Kaushik

    1983-01-01T23:59:59.000Z

    OF SCIENCE December 1983 Major Subject: Chemical Engineering THE EFFECT OF VELOCITY AND POROSITY PROFILES ON THE PERFORMANCE OF FIXED BED REACTORS A Thesis by KAUSHIK AHIN Approved as to style and content by: R. G. Anthony (Chairman) Aydin german... (m r) R. H. Loeppert (member) C. D. 1 and (Head of the Dept. ) December 1983 ABSTRACT THE Effect of Velocity and Porosity Profiles on the Performance of Fixed Bed Reactors (December 1983) Kaushik Amin, B. S. , M. S. University of Barcda...

  14. Electromagnetic wave propagation with negative phase velocity in regular black holes

    SciTech Connect (OSTI)

    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

    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.

  15. Quantitative estimates of velocity sensitivity to surface melt variations at a large Greenland outlet glacier

    E-Print Network [OSTI]

    Anderson, M.L.; Nettles, M.; Larsen, T.B.; Hamilton, Gordon S.; Stearns, Leigh

    2011-09-01T23:59:59.000Z

    front. Calving events at the glacier front produce tsunami signals in the tide-gauge record, which we use to verify our visual and seismic detections of major calving events. The combined calving dataset for 2008 that we use to correct the velocity... evolution in sensitivity to melt input indicates a nonlinear velocity response to surface melt, and points to the need for a better understanding of the response to melting, particularly as atmospheric temperatures rise. We believe that our results...

  16. Linearization of scan velocity of resonant vibrating-mirror beam deflectors

    DOE Patents [OSTI]

    Yeung, Edward S. (Ames, IA); Chen, Shun-Le (Long Island City, NY)

    1991-01-15T23:59:59.000Z

    A means and method for producing linerization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linerization is accomplished by considering sets of criteria for different scanning applications.

  17. Linearization of scan velocity of resonant vibrating-mirror beam deflectors

    DOE Patents [OSTI]

    Yeung, E.S.; Chen, S.L.

    1991-01-15T23:59:59.000Z

    A means and method for producing linearization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linearization is accomplished by considering sets of criteria for different scanning applications. 6 figures.

  18. Response to “Comment on ‘Velocity boundary conditions at a tokamak resistive wall’” [Phys. Plasmas 21, 094701 (2014)

    SciTech Connect (OSTI)

    Strauss, H. R., E-mail: hank@hrsfusion.com [HRS Fusion, West Orange, New Jersey 07052 (United States)

    2014-09-15T23:59:59.000Z

    A response is given to “Comment on ‘Velocity boundary conditions at a tokamak resistive wall’?” [Phys. Plasmas 21, 094701 (2014)].

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

    E-Print Network [OSTI]

    Narita, Norio

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

  20. Determination of elastic properties of a MnO{sub 2} coating by surface acoustic wave velocity dispersion analysis

    SciTech Connect (OSTI)

    Sermeus, J.; Glorieux, C., E-mail: christ.glorieux@fys.kuleuven.be [Laboratory for Acoustics and Thermal Physics, KU Leuven, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Sinha, R.; Vereecken, P. M. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Center for Surface Chemistry and Catalysis, KU Leuven, University of Leuven, Kasteelpark Arenberg 23, B-3001 Leuven (Belgium); Vanstreels, K. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium)

    2014-07-14T23:59:59.000Z

    MnO{sub 2} is a material of interest in the development of high energy-density batteries, specifically as a coating material for internal 3D structures, thus ensuring rapid energy deployment. Its electrochemical properties have been mapped extensively, but there are, to the best of the authors' knowledge, no records of the elastic properties of thin film MnO{sub 2}. Impulsive stimulated thermal scattering (ISTS), also known as the heterodyne diffraction or transient grating technique, was used to determine the Young's modulus (E) and porosity (?) of a 500?nm thick MnO{sub 2} coating on a Si(001) substrate. ISTS is an all optical method that is able to excite and detect surface acoustic waves (SAWs) on opaque samples. From the measured SAW velocity dispersion, the Young's modulus and porosity were determined to be E?=?25?±?1?GPa and ?=42±1%, respectively. These values were confirmed by independent techniques and determined by a most-squares analysis of the carefully fitted SAW velocity dispersion. This study demonstrates the ability of the presented technique to determine the elastic parameters of a thin, porous film on an anisotropic substrate.

  1. The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay Maps

    E-Print Network [OSTI]

    Grier, C J; Horne, Keith; Bentz, M C; Pogge, R W; Denney, K D; De Rosa, G; Martini, Paul; Kochanek, C S; Zu, Y; Shappee, B; Siverd, R; Beatty, T G; Sergeev, S G; Kaspi, S; Salvo, C Araya; Bird, J C; Bord, D J; Borman, G A; Che, X; Chen, C; Cohen, S A; Dietrich, M; Doroshenko, V T; Efimov, Yu S; Free, N; Ginsburg, I; Henderson, C B; King, A L; Mogren, K; Molina, M; Mosquera, A M; Nazarov, S V; Okhmat, D N; Pejcha, O; Rafter, S; Shields, J C; Skowron, J; Szczygiel, D M; Valluri, M; van Saders, J L

    2012-01-01T23:59:59.000Z

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum-entropy method for four objects: Mrk 335, Mrk 1501, 3C120, and PG2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H\\beta\\ emission line, but see tentative evidence of combined virial motion and infalling gas. The four velocity-delay maps show unique dynamical signatures for each object. For 3C120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the HeII 4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the HeII emission in Mrk 335 is consistent with an inclined disk. The maps for 3C120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and ...

  2. Blowoff characteristics of bluff-body stabilized conical premixed flames under upstream velocity modulation

    SciTech Connect (OSTI)

    Chaparro, Andres A.; Cetegen, Baki M. [Mechanical Engineering Department, University of Connecticut, Storrs, CT 06269-3139 (United States)

    2006-01-01T23:59:59.000Z

    This article presents experimental findings on the blowoff characteristics of conical premixed flames anchored at their apex by three different flame holders (rod, disk, and cone) in the presence of upstream velocity oscillations. Experiments were performed with propane-air mixtures at mixture velocities approaching the flame holder of 5, 10, and 15 m/s. The flow speed was modulated sinusoidally at frequencies up to 400 Hz with a constant-velocity modulation amplitude of u{sub rms}/U{sub m}=0.08 upstream of the flame holder. It was found that the blowoff equivalence ratio exhibits a dependence on the flow modulation frequency. Specifically, at low approach velocities (5 m/s), the effect of upstream flow modulation is to improve flame stability as evidenced by lower flame blowoff equivalence ratios for all three types of flame holders considered. At higher approach velocities (10 and 15 m/s), the disk- and cone-shaped flame holders exhibit less stability with increasing excitation frequency. The rod-shaped flame holder behavior is different at these higher velocities in that the flow modulation still provides enhanced flame stability. The flame stability results are supplemented with a detailed analysis of the flow field in the flame stabilization zone obtained by particle image velocimetry.

  3. Modeling of the Terminal Velocities of the Dust Ejected Material by the Impact

    E-Print Network [OSTI]

    M. Rengel; M. Kueppers; H. U. Keller; P. Gutierrez

    2007-01-03T23:59:59.000Z

    We compute the distribution of velocities of the particles ejected by the impact of the projectile released from NASA Deep Impact spacecraft on the nucleus of comet 9P/Tempel 1 on the successive 20 hours following the collision. This is performed by the development and use of an ill-conditioned inverse problem approach, whose main ingredients are a set of observations taken by the Narrow Angle Camera (NAC) of OSIRIS onboard the Rosetta spacecraft, and a set of simple models of the expansion of the dust ejecta plume for different velocities. Terminal velocities are derived using a maximum likelihood estimator. We compare our results with published estimates of the expansion velocity of the dust cloud. Our approach and models reproduce well the velocity distribution of the ejected particles. We consider these successful comparisons of the velocities as an evidence for the appropriateness of the approach. This analysis provides a more thorough understanding of the properties of the Deep Impact dust cloud.

  4. Measuring Stellar Radial Velocities with a Dispersed Fixed-Delay Interferometer

    E-Print Network [OSTI]

    Mahadevan, Suvrath; Ge, Jian; DeWitt, Curtis; Fleming, Scott W; Cohen, Roger; Crepp, Justin; Heuvel, Andrew Vanden

    2008-01-01T23:59:59.000Z

    We demonstrate the ability to measure precise stellar barycentric radial velocities with the dispersed fixed-delay interferometer technique using the Exoplanet Tracker (ET), an instrument primarily designed for precision differential Doppler velocity measurements using this technique. Our barycentric radial velocities, derived from observations taken at the KPNO 2.1 meter telescope, differ from those of Nidever et al. by 0.047 km/s (rms) when simultaneous iodine calibration is used, and by 0.120 km/s (rms) without simultaneous iodine calibration. Our results effectively show that a Michelson interferometer coupled to a spectrograph allows precise measurements of barycentric radial velocities even at a modest spectral resolution of R ~ 5100. A multi-object version of the ET instrument capable of observing ~500 stars per night is being used at the Sloan 2.5 m telescope at Apache Point Observatory for the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS), a wide-field radial velocity survey ...

  5. Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core-mantle boundary

    E-Print Network [OSTI]

    Ritsema, Jeroen

    Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core of earthquakes in Indonesia. Modeling of SKKS/SKS indicate that Ultra-Low Velocity Zones (ULVZs), layers, and M. S. Thorne (2009), Modeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones

  6. Seismic structure and ultra-low velocity zones at the base of the Earth's mantle beneath Southeast Asia

    E-Print Network [OSTI]

    Wen, Lianxing

    Seismic structure and ultra-low velocity zones at the base of the Earth's mantle beneath Southeast t We constrain seismic structure and ultra-low velocity zones near the Earth's core-mantle boundary that the strong scatterers represent ultra-low velocity zones (ULVZs). We suggest that the seismic structure

  7. THEORY OF DISPERSED FIXED-DELAY INTERFEROMETRY FOR RADIAL VELOCITY EXOPLANET SEARCHES

    SciTech Connect (OSTI)

    Van Eyken, Julian C.; Ge Jian; Mahadevan, Suvrath, E-mail: vaneyken@ipac.caltech.ed, E-mail: jge@astro.ufl.ed, E-mail: suvrath@astro.psu.ed [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611-2055 (United States)

    2010-07-15T23:59:59.000Z

    The dispersed fixed-delay interferometer (DFDI) represents a new instrument concept for high-precision radial velocity (RV) surveys for extrasolar planets. A combination of a Michelson interferometer and a medium-resolution spectrograph, it has the potential for performing multi-object surveys, where most previous RV techniques have been limited to observing only one target at a time. Because of the large sample of extrasolar planets needed to better understand planetary formation, evolution, and prevalence, this new technique represents a logical next step in instrumentation for RV extrasolar planet searches, and has been proven with the single-object Exoplanet Tracker (ET) at Kitt Peak National Observatory, and the multi-object W. M. Keck/MARVELS Exoplanet Tracker at Apache Point Observatory. The development of the ET instruments has necessitated fleshing out a detailed understanding of the physical principles of the DFDI technique. Here we summarize the fundamental theoretical material needed to understand the technique and provide an overview of the physics underlying the instrument's working. We also derive some useful analytical formulae that can be used to estimate the level of various sources of error generic to the technique, such as photon shot noise when using a fiducial reference spectrum, contamination by secondary spectra (e.g., crowded sources, spectroscopic binaries, or moonlight contamination), residual interferometer comb, and reference cross-talk error. Following this, we show that the use of a traditional gas absorption fiducial reference with a DFDI can incur significant systematic errors that must be taken into account at the precision levels required to detect extrasolar planets.

  8. VELOCITY CHARACTERISTICS OF EVAPORATED PLASMA USING HINODE/EUV IMAGING SPECTROMETER

    SciTech Connect (OSTI)

    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

    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.

  9. Effect of gas velocity on the weakly nonlinear instability of a planar viscous sheet

    SciTech Connect (OSTI)

    Yang, Li-Jun, E-mail: yanglijun@buaa.edu.cn; Chen, Pi-Min; Wang, Chen [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

    2014-07-15T23:59:59.000Z

    A weakly nonlinear spatial instability of a two-dimensional planar viscous sheet for sinuous disturbances in a co-flowing inviscid gas stream is investigated theoretically, with an emphasis on the effect of the surrounding gas velocity. The solutions of the second-order interface disturbances are derived and the wave deformation has been computed. The results indicate that the second-order surface disturbance of the fundamental sinuous mode is varicose, which causes the thinning and the subsequent breakup of the liquid sheet. The nonlinear behaviors of the planar sheet are quite sensitive to variations in gas-to-liquid velocity ratio. The deviation of the velocity ratio from the value of unity leads to a larger growth rate, a larger second-order initial amplitude, and a shorter breakup length, and therefore enhances the instability. The growth rates predicted by the present nonlinear analysis according to the shortest breakup length are generally smaller than the linear predictions and can better conform to the experimental measures of Barreras et al. [“Linear instability analysis of the viscous longitudinal perturbation on an air-blasted liquid sheets,” Atomization Sprays 11, 139 (2001)]. Furthermore, the wave deformations of the most unstable disturbances are presented. The nonlinear instability of the planar sheet for a fixed velocity difference is performed. An equal increase of the gas and liquid velocity reduces the spatial growth rate and increases the breakup length, but generally has no influences on the second-order initial amplitude and the wavelength of the disturbance.

  10. LDV measurements of the velocity field within a ribbed internal duct flow

    SciTech Connect (OSTI)

    Huckle, E.; Pantelic, D.; Hu, K.; Jones, S.; Travkin, V.; Catton, I.

    1999-07-01T23:59:59.000Z

    Laser Doppler velocimetry (LDV) has been used to measure the velocity field in an internal duct flow of air with regular rib roughness. The experiments were conducted to study the effect regular wall obstacles have on the flow velocity field. The instantaneous u and v velocities were measured in both a smooth and rough rectangular duct. For the smooth channel the wind tunnel Reynolds number capability was first investigated and was shown to be linear with blower shaft frequency, having a range of 13,000--42,000. Next, the turbulent velocity profiles were measured in the smooth channel for 6 different blower speeds (Reynolds numbers), and the results greatly resembled those found in previous literature. Twenty sets of rectangular, 6.35 mm x 6.35 mm ribs were then mounted to the top and bottom of the channel with a spacing of 75 mm (P/H = 11.8). A grid of nodes were selected and the turbulent velocities were measured for a given Reynolds number, and are presented and discussed. Valuable insight was gained which will aid in future studies intended to measure the Reynolds stress and other closure terms.

  11. VISAR (Velocity Interferometer System for Any Reflector): Line-imaging interferometer

    SciTech Connect (OSTI)

    Hemsing, W.F.; Mathews, A.R.; Warnes, R.H.; Whittemore, G.R.

    1990-01-01T23:59:59.000Z

    This paper describes a Velocity Interferometer System for Any Reflector (VISAR) technique that extends velocity measurements from single points to a line. Single-frequency argon laser light was focused through a cylindrical lens to illuminate a line on a surface. The initially stationary, flat surface was accelerated unevenly during the experiment. Motion produced a Doppler-shift of light reflected from the surface that was proportional to the velocity at each point. The Doppler-shifted image of the illuminated line was focused from the surface through a push-pull VISAR interferometer where the light was split into four quadrature-coded images. When the surface accelerated, the Doppler-shift caused the interference for each point on each line image to oscillate sinusoidally. Coherent fiber optic bundles transmitted images from the interferometer to an electronic streak camera for sweeping in time and recording on film. Data reduction combined the images to yield a continuous velocity and displacement history for all points on the surface that reflected sufficient light. The technique was demonstrated in an experiment where most of the surface was rapidly driven to a saddle shape by an exploding foil. Computer graphics were used to display the measured velocity history and to aid visualization of the surface motion. 6 refs., 8 figs.

  12. Measurements of Outflow Velocities in On-Disk Plumes from EIS Hinode Observations

    E-Print Network [OSTI]

    Fu, Hui; Li, Bo; Huang, Zhenghua; Jiao, Fangran; Mou, Chaozhou

    2014-01-01T23:59:59.000Z

    The contribution of plumes to the solar wind has been subject to hot debate in the past decades. The EUV Imaging Spectrometer (EIS) on board Hinode provides a unique means to deduce outflow velocities at coronal heights via direct Doppler shift measurements of coronal emission lines. Such direct Doppler shift measurements were not possible with previous spectrometers. We measure the outflow velocity at coronal heights in several on-disk long-duration plumes, which are located in coronal holes and show significant blue shifts throughout the entire observational period. In one case, a plume is measured 4 hours apart. The deduced outflow velocities are consistent, suggesting that the flows are quasi-steady. Furthermore, we provide an outflow velocity profile along the plumes, finding that the velocity corrected for the line-of-sight effect can reach 10 km s$^{-1}$ at 1.02 $R_{\\odot}$, 15 km s$^{-1}$ at 1.03 $R_{\\odot}$, and 25 km s$^{-1}$ at 1.05 $R_{\\odot}$. This clear signature of steady acceleration, combined...

  13. Computation of Weakly-Compressible Highly-Viscous Polymeric Liquid Flows

    E-Print Network [OSTI]

    Grant, P. W.

    such circumstances, the speed of sound is much larger than the velocity of the liquid, resulting in fast pressure, the ratio of fluid velocity to the speed of sound ( cuMa /= ), characterises the influence1 Computation of Weakly-Compressible Highly-Viscous Polymeric Liquid Flows M. F. Webster 1*, I. J

  14. The relation between seismic P- and S-wave velocity dispersion in saturated rocks

    SciTech Connect (OSTI)

    Mavko, G. [Stanford Univ., CA (United States). Dept. of Geophysics] [Stanford Univ., CA (United States). Dept. of Geophysics; Jizba, D. [CSTJF, Pau (France)] [CSTJF, Pau (France)

    1994-01-01T23:59:59.000Z

    Seismic velocity dispersion in fluid-saturated rocks appears to be dominated by two mechanisms: the large scale mechanism modeled by Biot, and the local flow or squirt mechanism. The two mechanisms can be distinguished by the ratio of P- to S-wave dispersions, or more conveniently, by the ratio of dynamic bulk to shear compliance dispersions derived from the wave velocities. The authors` formulation suggests that when local flow dominates, the dispersion of the shear compliance will be approximately 4/15 the dispersion of the compressibility. When the Biot mechanism dominates, the constant of proportionality is much smaller. Their examination of ultrasonic velocities from 40 sandstones and granites shows that most, but not all, of the samples were dominated by local flow dispersion, particularly at effective pressures below 40 MPa.

  15. Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

    SciTech Connect (OSTI)

    Jacobsen, A. S., E-mail: Ajsen@fysik.dtu.dk; Salewski, M.; Korsholm, S. B.; Leipold, F.; Nielsen, S. K.; Rasmussen, J.; Stejner, M. [Association Euratom - DTU, Technical University of Denmark, Department of Physics, Kgs. Lyngby (Denmark); Eriksson, J.; Ericsson, G.; Hjalmarsson, A. [Association Euratom - VR, Uppsala University, Department of Physics and Astronomy, Uppsala (Sweden)

    2014-11-15T23:59:59.000Z

    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR.

  16. Nonclassical Velocity Statistics in a Turbulent Atomic Bose-Einstein Condensate

    SciTech Connect (OSTI)

    White, A. C.; Barenghi, C. F.; Proukakis, N. P.; Youd, A. J.; Wacks, D. H. [School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU (United Kingdom)

    2010-02-19T23:59:59.000Z

    In a recent experiment Paoletti et al. [Phys. Rev. Lett. 101, 154501 (2008)] monitored the motion of tracer particles in turbulent superfluid helium and inferred that the velocity components do not obey the Gaussian statistics observed in ordinary turbulence. Motivated by their experiment, we create a small 3D turbulent state in an atomic Bose-Einstein condensate, compute directly the velocity field, and find similar nonclassical power-law tails. We obtain similar results in 2D trapped and 3D homogeneous condensates, and in classical 2D vortex points systems. This suggests that non-Gaussian turbulent velocity statistics describe a fundamental property of quantum turbulence. We also track the decay of the vortex tangle in the presence of the thermal cloud.

  17. Doppler cooling with coherent trains of laser pulses and a tunable velocity comb

    SciTech Connect (OSTI)

    Ilinova, Ekaterina; Ahmad, Mahmoud; Derevianko, Andrei [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

    2011-09-15T23:59:59.000Z

    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.

  18. On the role of spectral resolution in velocity shear layer measurements by Doppler reflectometry

    SciTech Connect (OSTI)

    Happel, T.; Blanco, E.; Estrada, T. [Laboratorio Nacional de Fusion, Association Euratom-Ciemat, 28040 Madrid (Spain)

    2010-10-15T23:59:59.000Z

    The signal quality of a Doppler reflectometer depends strongly on its spectral resolution, which is influenced by the microwave beam properties and the radius of curvature of the cutoff layer in the plasma. If measured close to a strong perpendicular velocity shear layer, the spectrum of the backscattered signal is influenced by different velocities. This can give rise to two Doppler shifted peaks in the spectrum as observed in TJ-II H-mode plasmas. It is shown by two-dimensional full wave simulations that the two peaks are separable provided the spectral resolution of the system is sufficient. However, if the spectral resolution is poor, the two peaks blend into one and yield an intermediate and incorrect velocity.

  19. RADIAL VELOCITIES OF GALACTIC O-TYPE STARS. II. SINGLE-LINED SPECTROSCOPIC BINARIES

    SciTech Connect (OSTI)

    Williams, S. J.; Gies, D. R. [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 4106, Atlanta, GA 30302-4106 (United States); Hillwig, T. C. [Department of Physics and Astronomy, Valparaiso University, Valparaiso, IN 46383 (United States); McSwain, M. V. [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015 (United States); Huang, W., E-mail: swilliams@chara.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: todd.hillwig@valpo.edu, E-mail: mcswain@lehigh.edu, E-mail: hwenjin@astro.washington.edu [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States)

    2013-02-01T23:59:59.000Z

    We report on new radial velocity measurements of massive stars that are either suspected binaries or lacking prior observations. This is part of a survey to identify and characterize spectroscopic binaries among O-type stars with the goal of comparing the binary fraction of field and runaway stars with those in clusters and associations. We present orbits for HDE 308813, HD 152147, HD 164536, BD-16 Degree-Sign 4826, and HDE 229232, Galactic O-type stars exhibiting single-lined spectroscopic variation. By fitting model spectra to our observed spectra, we obtain estimates for effective temperature, surface gravity, and rotational velocity. We compute orbital periods and velocity semiamplitudes for each system and note the lack of photometric variation for any system. These binaries probably appear single-lined because the companions are faint and because their orbital Doppler shifts are small compared to the width of the rotationally broadened lines of the primary.

  20. Radial Velocities of Galactic O-Type Stars. II. Single-lined Spectroscopic Binaries

    E-Print Network [OSTI]

    Williams, S J; Hillwig, T C; McSwain, M V; Huang, W

    2012-01-01T23:59:59.000Z

    We report on new radial velocity measurements of massive stars that are either suspected binaries or lacking prior observations. This is part of a survey to identify and characterize spectroscopic binaries among O-type stars with the goal of comparing the binary fraction of field and runaway stars with those in clusters and associations. We present orbits for HDE 308813, HD 152147, HD 164536, BD-16 4826 and HDE 229232, Galactic O-type stars exhibiting single-lined spectroscopic variation. By fitting model spectra to our observed spectra we obtain estimates for effective temperature, surface gravity, and rotational velocity. We compute orbital periods and velocity semiamplitudes for each system and note the lack of photometric variation for any system. These binaries probably appear single-lined because the companions are faint and because their orbital Doppler shifts are small compared to the width of the rotationally broadened lines of the primary.

  1. The Turbulence Velocity Power Spectrum of Neutral Hydrogen in the Small Magellanic Cloud

    E-Print Network [OSTI]

    Chepurnov, Alexey; Lazarian, Alex; Stanimirovic, Snezana

    2015-01-01T23:59:59.000Z

    We present the results of the Velocity Coordinate Spectrum (VCS) technique to calculate the velocity power spectrum of turbulence in the Small Magellanic Cloud (SMC) in 21cm emission. We have obtained a velocity spectral index of -3.85 and an injection scale of 2.3 kpc. The spectral index is steeper than the Kolmogorov index which is expected for shock-dominated turbulence which is in agreement with past works on the SMC gas dynamics. The injection scale of 2.3 kpc suggests that tidal interactions with the Large Magellanic Cloud are the dominate driver of turbulence in this dwarf galaxy. This implies turbulence maybe driven by multiple mechanisms in galaxies in addition to supernova injection and that galaxy-galaxy interactions may play an important role.

  2. Velocity of sound measurements in gaseous per-fluorocarbons and their custom mixtures

    E-Print Network [OSTI]

    Vacek, V; Lindsay, S

    2000-01-01T23:59:59.000Z

    An inexpensive sonar instrument was prepared for measurements of sound velocity in two fluorocarbon vapors; per-fluoro-n-propane (C3F8), per-fluoro-n-butane (C4F10), and their custom mixtures. The apparatus, measurement principle and instrument software are described. All sound velocity measurements in per-fluorocarbons were made in the low pressure range between 0.01 and 0.4 MPa, and at temperatures between 253 and 303 K. The purity of the C3F8 and C4F10 samples was checked using gas chromatography. Uncertainties in the speed of sound measurements were better than ± 0.1 %. Comparisons were made with theoretical predictions of sound velocity for the two individual components. The instrument was then used for concentration monitoring of custom C3F8/C4F10 mixtures.

  3. Scale effects on velocity dispersion: From ray to effective medium theories in stratified media

    SciTech Connect (OSTI)

    Marion, D. (Elf Aquitaine, Pau (France)); Mukerji, T.; Mavko, G. (Stanford Univ., CA (United States). Rockphysics Lab.)

    1994-10-01T23:59:59.000Z

    Wave propagation in stratified media may be explained by ray theory, effective medium theory, or scattering theory depending on the scales of wavelength and layer spacing. To effectively integrate and use seismic data ate different frequencies and widely varying scales, it is essential to understand the domain of applicability of long and short wavelength behavior and the transition between them. A joint experimental and theoretical study was conducted to investigate velocity behavior at the transition from ray theory to effective medium theory in stratified media. Velocity measurements were performed at 50 and 500 kHz on periodic media composed of steel and plastic discs. The ratio of wavelength to layer spacing, [lambda]/d, spanned more than two orders of magnitude between 0.1 and 50, and the volume fraction of steel ranged from 9 to 89 percent by volume. The results confirm that velocities in stratified media depend on composition and are controlled by the ratio of wavelength to layer spacing. Velocities in the short wavelength limit are generally faster than velocities in the long wavelength limit. The authors find that transition from ray to effective medium approximations occurs over a narrow range of [lambda]/d at a value of approximately 10. The amount of velocity change increases with impedance contrast, but the value of [lambda]/d at the transition is generally independent of the composition of the stratified medium. The numerically simulated waveforms are in close agreement with the experimentally observed delayed first arrival in the long wavelength limit and with the reduced amplitudes at the transition from short to long wavelength regime.

  4. DETERMINATION OF NON-THERMAL VELOCITY DISTRIBUTIONS FROM SERTS LINEWIDTH OBSERVATIONS

    SciTech Connect (OSTI)

    Coyner, Aaron J. [Department of Physics, Catholic University of America, 620 Michigan Avenue, Washington, DC 20064 (United States); Davila, Joseph M., E-mail: aaron.j.coyner@nasa.gov [Code 671, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2011-12-01T23:59:59.000Z

    Non-thermal velocities obtained from the measurement of coronal Extreme Ultraviolet (EUV) linewidths have been consistently observed in solar EUV spectral observations and have been theorized to result from many plausible scenarios including wave motions, turbulence, or magnetic reconnection. Constraining these velocities can provide a physical limit for the available energy resulting from unresolved motions in the corona. We statistically determine a series of non-thermal velocity distributions from linewidth measurements of 390 emission lines from a wide array of elements and ionization states observed during the Solar Extreme Ultraviolet Research Telescope and Spectrograph 1991-1997 flights covering the spectral range 174-418 A and a temperature range from 80,000 K to 12.6 MK. This sample includes 248 lines from active regions, 101 lines from quiet-Sun regions, and 41 lines were observed from plasma off the solar limb. We find a strongly peaked distribution corresponding to a non-thermal velocity of 19-22 km s{sup -1} in all three of the quiet-Sun, active region, and off-limb distributions. For the possibility of Alfven wave resonance heating, we find that velocities in the core of these distributions do not provide sufficient energy, given typical densities and magnetic field strengths for the coronal plasma, to overcome the estimated coronal energy losses required to maintain the corona at the typical temperatures working as the sole mechanism. We find that at perfect efficiency 50%-60% of the needed energy flux can be produced from the non-thermal velocities measured.

  5. Bayesian Reconstruction of the Velocity Distribution of Weakly Interacting Massive Particles from Direct Dark Matter Detection Data

    E-Print Network [OSTI]

    Chung-Lin Shan

    2014-08-04T23:59:59.000Z

    In this paper, we extended our earlier work on the reconstruction of the (time-averaged) one-dimensional velocity distribution of Galactic Weakly Interacting Massive Particles (WIMPs) and introduce the Bayesian fitting procedure to the theoretically predicted velocity distribution functions. In this reconstruction process, the (rough) velocity distribution reconstructed by using raw data from direct Dark Matter detection experiments directly, i.e. measured recoil energies, with one or more different target materials, has been used as "reconstructed-input" information. By assuming a fitting velocity distribution function and scanning the parameter space based on the Bayesian analysis, the astronomical characteristic parameters, e.g. the Solar and Earth's Galactic velocities, will be pinned down as the output results. Our Monte-Carlo simulations show that this Bayesian scanning procedure could reconstruct the true (input) WIMP velocity distribution function pretty precisely with negligible systematic deviations of the reconstructed characteristic Solar and Earth's velocities and 1 sigma statistical uncertainties of <~ 20 km/s. Moreover, for the use of an improper fitting velocity distribution function, our reconstruction process could still offer useful information about the shape of the velocity distribution. In addition, by comparing these estimates to theoretical predictions, one could distinguish different (basic) functional forms of the theoretically predicted one-dimensional WIMP velocity distribution function with 2 sigma to 4 sigma confidence levels.

  6. Velocity Induced Neutrino Oscillation and its Possible Implications for Long Baseline Neutrinos

    E-Print Network [OSTI]

    Banik, Amit Dutta

    2014-01-01T23:59:59.000Z

    If the three types of active neutrinos possess different maximum attainable velocities and the neutrino eigenstates in the velocity basis are different from those in the flavour (and mass) basis then this will induce a flavour oscillation in addition to the normal mass flavour oscillation. Here we study such an oscillation scenario in three neutrino framework including also the matter effect and apply our results to demonstrate its consequences for long baseline neutrinos. We also predict the possible signatures in terms of yields in a possible long baseline neutrino experiment.

  7. The seasonal variation of the zonal velocity of the Atlantic Equatorial Undercurrent

    E-Print Network [OSTI]

    Olling, Charles Randolph

    1977-01-01T23:59:59.000Z

    to the east) at 30 m based on 43 22 23 instrumental observations in the latitude band 0 15'N-0 15'S (om/s) . 44 Zonal velocity (positive to the east) at 50 m based on instrumental observations in the latitude band 0 15'R 0 15'S (cm.../s) . ~ ~ . ~ . . ~. . . ~ ~ ~ ~ . . ~ 45 Zonal velocity (positive to the east) at 80 m based on 24 instrumental observations in the latitude band 0 15'RM 15'S (om/s) ~ ~ Zonal velooity (positive to the east) at 100 m instrumental observations in the latitude band. 0 15'N 0 15'S (om/s...

  8. Velocity models, material balance and solution convergence in streamline-based simulation

    E-Print Network [OSTI]

    Sabir, Kamran

    2002-01-01T23:59:59.000Z

    of {x, y, z) to a unit cube in the pseudo space of (a, P, y). This code also determines the velocity models, and sketches the streamlines in the domain. Calculation of time of flight is also incorporated in the code. Another code was written... be obtained from the velocity components. 2. 2 Five-Spot Waterflooding Pattern Morel-Seytoux shows that the following are the potential (P) and stream (r[r) functions for five-spot waterflooding pattern (quarter five-spot symmetry element): ] 1 ? rn[4x...

  9. On the terminal velocity of sedimenting particles in a flowing fluid

    E-Print Network [OSTI]

    Marco Martins Afonso

    2008-06-11T23:59:59.000Z

    The influence of an underlying carrier flow on the terminal velocity of sedimenting particles is investigated both analytically and numerically. Our theoretical framework works for a general class of (laminar or turbulent) velocity fields and, by means of an ordinary perturbation expansion at small Stokes number, leads to closed partial differential equations (PDE) whose solutions contain all relevant information on the sedimentation process. The set of PDE's are solved by means of direct numerical simulations for a class of 2D cellular flows (static and time dependent) and the resulting phenomenology is analysed and discussed.

  10. Relativistic velocity addition and the relativity of space and time intervals

    E-Print Network [OSTI]

    J. H. Field

    2009-02-06T23:59:59.000Z

    A thought experiment first proposed by Sartori is analysed using the parallel velocity addition formula of special relativity. The distances and proper-time intervals between some similarly defined spatial coincidence events are found to be widely different in different inertial frames. This relativity of space and time intervals is quite distinct from the well-known time-dilatation and length contraction effects of special relativity. Sartori's claimed derivation of the parallel velocity addition formula, assuming relativistic time dilatation, based on the thought experiment, is shown to be fortuitous.

  11. Compressional-wave and shear-wave velocities from long-spaced sonic waveforms

    E-Print Network [OSTI]

    Lake, Leonard Cornelius

    1986-01-01T23:59:59.000Z

    COMPRESSIONAL-WAVE AND SHEAR-WAVE VELOCITIES FROM LONG- SPACED SONIC WAVEFORMS A Thesis LEONARD CORNELIUS LAKE Submitted to the Graduate College of Texas AdtM University in partial fulftllment of the requirements for thc degree of MASTER... OF SCIENCE Mav 19S6 Major Subject: Geophystcs COMPRESSIONAL-WAVE AND SHEAR-WAVE VELOCITIES FROM LONG- SPACED SONIC WAVEFORMS A Thesis LEONARD CORNELIUS LAKE Approved as to style and content by: erry W. neer (C)tairman of Commtttee) R bert. R. Unterb...

  12. Radial Velocity Studies of Close Binary Stars.VII. Methods and Uncertainties

    E-Print Network [OSTI]

    S. M. Rucinski

    2002-05-29T23:59:59.000Z

    Methods used in the radial-velocity program of short-period binary systems at the David Dunlap Observatory are described with particular stress on the Broadening Function (BF) formalism. This formalism has permitted determination of radial velocities from complex spectra of multiple-component systems with component stars showing very different degree of rotational line broadening. The statistics of random errors of orbital parameters is discussed on the basis of the available orbital solutions presented in the six previous papers of the series, each with ten orbits. The difficult matter of systematic uncertainties in orbital parameters is illustrated for one typical case of GM Dra from the most recent Paper VI.

  13. Laser induced fluorescence measurements of ion velocity and temperature of drift turbulence driven sheared plasma flow in a linear helicon plasma device

    SciTech Connect (OSTI)

    Chakraborty Thakur, S.; Fedorczak, N.; Manz, P.; Tynan, G. R.; Xu, M. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California 92093 (United States); Center for Energy Research, University of California at San Diego, San Diego, California 92093 (United States); McCarren, D.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Lee, T. [Center for Energy Research, University of California at San Diego, San Diego, California 92093 (United States)

    2012-08-15T23:59:59.000Z

    Using laser induced fluorescence (LIF), radial profiles of azimuthal ion fluid velocity and ion temperature are measured in the controlled shear de-correlation experiment (CSDX) linear helicon plasma device. Ion velocities and temperatures are derived from the measured Doppler broadened velocity distribution functions of argon ions. The LIF system employs a portable, high power (>300 mW), narrowband ({approx}1 MHz) tunable diode laser-based system operating at 668.614 nm. Previous studies in CSDX have shown the existence of a radially sheared azimuthal flow as measured with time delay estimation methods and Mach probes. Here, we report the first LIF measurements of sheared plasma fluid flow in CSDX. Above a critical magnetic field, the ion fluid flow profile evolves from radially uniform to peaked on axis with a distinct reversed flow region at the boundary, indicating the development of a sheared azimuthal flow. Simultaneously, the ion temperature also evolves from a radially uniform profile to a profile with a gradient. Measurements in turbulent and coherent drift wave mode dominated plasmas are compared.

  14. Control of the chaotic velocity dispersion of a cold electron beam interacting with electrostatic waves

    E-Print Network [OSTI]

    Guido Ciraolo; Cristel Chandre; Ricardo Lima; Marco Pettini; Michel Vittot

    2006-07-31T23:59:59.000Z

    In this article we present an application of a method of control of Hamiltonian systems to the chaotic velocity diffusion of a cold electron beam interacting with electrostatic waves. We numerically show the efficiency and robustness of the additional small control term in restoring kinetic coherence of the injected electron beam.

  15. The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    The ion experiment onboard the Interball-Aurora satellite; initial results on velocity / Accepted: 10 March 1998 Abstract. The Toulouse ION experiment ¯own on the Russian Interball-Aurora mission perform measurements in the energy range $10 eV±20 000 eV. The Interball- Aurora spacecraft was launched

  16. Numerical investigation of low-velocity impacts on monolithic and laminated safety glass

    E-Print Network [OSTI]

    Birmingham, University of

    Numerical investigation of low-velocity impacts on monolithic and laminated safety glass Researcher objects are one of the most common incidents to impact on glass floors or stairs during day to day experienced during hard body impacts on monolithic and laminated safety glass, mainly of structural use

  17. Water velocity and the nature of critical flow in large rapids on the Colorado River, Utah

    E-Print Network [OSTI]

    Christopher S. Magirl,1 Jeffrey W. Gartner,2 Graeme M. Smart,3 and Robert H. Webb2 Received 13 January 2009-surface velocity and depth soundings alone. Citation: Magirl, C. S., J. W. Gartner, G. M. Smart, and R. H. Webb quantitative data on rapids. [3] Tinkler [1997] used an electromagnetic current meter to measure flow in a fast

  18. Increase of shear wave velocity before the 1998 eruption of Merapi volcano (Indonesia)

    E-Print Network [OSTI]

    Snieder, Roel

    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

  19. Shock initiation studies of low density HMX using electromagnetic particle velocity and PVDF stress gauges

    SciTech Connect (OSTI)

    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

    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.

  20. Shock Initiation of New and Aged PBX 9501 Measured with Embedded Electromagnetic Particle Velocity Gauges

    SciTech Connect (OSTI)

    L. G. Hill; R. L. Gustavsen; R. R. Alcon; S. A. Sheffield

    1999-09-01T23:59:59.000Z

    We have used an embedded electromagnetic particle velocity gauge technique to measure the shock initiation behavior in PBX 9501 explosive. Up to twelve separate particle velocity wave profile measurements have been made at different depths in a single experiment. These detail the growth from an input shock to a detonation. In addition, another gauge element called a ''shock tracker'' has been used to monitor the progress of the shock front as a function of time and position as it moves through the explosive sample. This provides data similar to that obtained in a traditional explosively driven wedge test and is used to determine the position and time that the wave attains detonation. Run distance-to-detonation vs. input pressure (Pop-plot) data and particle velocity wave profile data have been obtained on new PBX 9501 pressed to densities of 1.826, 1.830, and 1.837 g/cm{sup 3}. In addition, the same measurements were performed on aged material recovered from dismantled W76 and W78 weapons. The input pressure range covered was 3.0 to 5.2 GPa. All results to date show shock sensitivity to be a function only of the initial density and not of age. PBX 9501 shock initiates the same after 17 years in stockpile as it does on the day it is pressed. Particle velocity wave profiles show mixed heterogeneous initiation (growth in the front) and homogeneous initiation (growth behind the front).

  1. The power spectrum of the Milky Way: Velocity fluctuations in the Galactic disk

    E-Print Network [OSTI]

    Bovy, Jo; Pérez, Ana E García; Zasowski, Gail

    2014-01-01T23:59:59.000Z

    We investigate the kinematics of stars in the mid-plane of the Milky Way on scales between 25 pc and 10 kpc with data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Radial Velocity Experiment (RAVE), and the Geneva-Copenhagen Survey (GCS). Using red-clump stars in APOGEE, we determine the large-scale line-of-sight velocity field out to 5 kpc from the Sun in (0.75 kpc)^2 bins. The solar motion is the largest contribution to the power on large scales after subtracting an axisymmetric rotation field; we determine the solar motion by minimizing the large-scale power to be V_sun = 24+/-1 (ran.)+/-2 (syst [V_c])+/-5 (syst. [large-scale]) km/s, where the systematic uncertainty is due to (a) a conservative 20 km/s uncertainty in V_c and (b) the estimated power on unobserved larger scales. Combining the APOGEE peculiar-velocity field with red-clump stars in RAVE out to 2 kpc from the Sun and with local GCS stars, we determine the power spectrum of residual velocity fluctuations in the Mi...

  2. Wind Velocities at the Chajnantor and Mauna Kea Sites and the Effect on MMA Pointing

    E-Print Network [OSTI]

    Groppi, Christopher

    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

  3. Probabilistic Velocity Estimation for Autonomous Miniature Airships using Thermal Air Flow Sensors

    E-Print Network [OSTI]

    Teschner, Matthias

    Probabilistic Velocity Estimation for Autonomous Miniature Airships using Thermal Air Flow Sensors J¨org M¨uller Oliver Paul Wolfram Burgard Abstract-- Recently, autonomous miniature airships have be- come a growing research field. Whereas airships are attractive as they can move freely in the three

  4. $ ^T)) \\ ^ / f l \\ Rise-M-2597 of Mass and Velocity Measurements

    E-Print Network [OSTI]

    in flight without use of optical equipment has been tested. The mass is measured by a microwave system, control of density profile, diagnostic purposes, etc.. In any case it is imports it to be able to measureh- $ ^T)) \\ ^ / f l \\ Rise-M-2597 of Mass and Velocity Measurements on Pellets in Flight

  5. Vorticity and Divergence of Surface Velocities Near Shore JEROME A. SMITH

    E-Print Network [OSTI]

    Smith, Jerome A.

    Vorticity and Divergence of Surface Velocities Near Shore JEROME A. SMITH Scripps Institution, and nearshore mixing-scale motions are generally undersampled (but see, e.g., Smith and Largier 1995; Johnson m 300 m on a side (Smith 2002a,b). Thus, these data focus more toward the small end of the range

  6. Tectonic velocities, dynamic topography, and relative sea level Laurent Husson1,2

    E-Print Network [OSTI]

    Husson, Laurent

    ] Dynamic topography is the vertical component of the response of an interface, like the surface may decrease dynamic topography amplitudes at the surface [Hager, 1984]. Thus, our use of a mantleTectonic velocities, dynamic topography, and relative sea level Laurent Husson1,2 and Clinton P

  7. OPTIMIZATION OF RUNNING STRATEGIES BASED ON ANAEROBIC ENERGY AND VARIATIONS OF VELOCITY

    E-Print Network [OSTI]

    OPTIMIZATION OF RUNNING STRATEGIES BASED ON ANAEROBIC ENERGY AND VARIATIONS OF VELOCITY AMANDINE extend this analysis, based on the equation of motion and aerobic energy, to include a balance of anaerobic energy (or accumulated oxygen deficit) and an energy recreation term when the speed decreases. We

  8. Vertically Loaded Anchor: Drag Coefficient, Fall Velocity, and Penetration Depth using Laboratory Measurements

    E-Print Network [OSTI]

    Cenac, William

    2011-08-08T23:59:59.000Z

    /15 scale model was attached to a tow carriage and towed through a water-filled tank to measure the drag forces and evaluate the drag coefficient. The anchor terminal velocity was measured using underwater cameras to track the free fall of the model anchor...

  9. Instruments and Methods Glacier velocities from time-lapse photos: technique development

    E-Print Network [OSTI]

    Box, Jason E.

    Instruments and Methods Glacier velocities from time-lapse photos: technique development and first West Greenland marine-terminating glaciers as part of the Extreme Ice Survey (EIS). EIS cameras began imaging the lowest 4 km2 of the glacier at hourly intervals throughout sunlit periods of the year

  10. New velocity map and mass-balance estimate of Mertz Glacier, East Antarctica, derived from Landsat

    E-Print Network [OSTI]

    Berthier, Etienne

    streams hasbeen measured recently. Pine Island Glacier accelerated by 18 Æ2% between 1992 and 2000 (Rignot-moving glaciers. Repeat visible or near-infrared images of the same area can be used to track the displace- mentNew velocity map and mass-balance estimate of Mertz Glacier, East Antarctica, derived from Landsat

  11. Manipulating the Future: Predictor Based Feedback for Velocity Control in Virtual Environment Navigation

    E-Print Network [OSTI]

    New Hampshire, University of

    Manipulating the Future: Predictor Based Feedback for Velocity Control in Virtual Environment control. The predictor indicates to the user where and how fast he or sheis travelling and hasadirect manipulation feel to it. Experiences using the predictor to navigate over digital terrain maps are discussed

  12. Flying Drosophila stabilize their vision-based velocity controller by sensing wind with their antennae

    E-Print Network [OSTI]

    Fuller, Sawyer Buckminster

    in flight control is unknown. We manipulated the antennal function of fruit flies by ablating their aristae regulator by fitting parameters of candidate models to our exper- imental data. The model suggestsFlying Drosophila stabilize their vision-based velocity controller by sensing wind

  13. Evolution of seismic velocities in heavy oil sand reservoirs during thermal recovery process

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Evolution of seismic velocities in heavy oil sand reservoirs during thermal recovery process localiser la chambre à vapeur. INTRODUCTION [1] Huge quantities of heavy oils (heavy oil, extra heavy oil. Larribau 64018 Pau Cedex, France Oil and Gas Science and Technology 2012, 67 (6), 1029-1039, doi:10

  14. Damage and seismic velocity structure of pulverized rocks near the San Andreas Fault

    E-Print Network [OSTI]

    Ben-Zion, Yehuda

    Damage and seismic velocity structure of pulverized rocks near the San Andreas Fault Marieke Rempe south of Littlerock, California. The examined site has a strongly asymmetric damage structure with respect to the SAF core. The conglomerates to the southwest show little to no damage, whereas a ~100 m

  15. Velocities of deep water reservoir sands De-hua Han, University of Houston

    E-Print Network [OSTI]

    and glass bean mixture (Zimmer, et al., 2002). Texture of deep-water sands Core samples come from two wellsVelocities of deep water reservoir sands De-hua Han, University of Houston M. Batzle, Colorado the application for DHI techniques. Summary In deep-water sedimentary processes, compaction is a major force

  16. Effect of dynamic level in drumming: Measurements of striking velocity, force, and

    E-Print Network [OSTI]

    Hansen, René Rydhof

    a drumstick equipped with strain gauges, and the bending deformation of the stick provided an estimate of the contact force between drumstick and drumhead. The data shows close relationship between the height to which the drumstick is lifted before a stroke, and its striking velocity. The players' different control

  17. Determining the Terminal Velocity and the Particle Size of Epoxy Based Fluids in the Wellbore

    E-Print Network [OSTI]

    Turkmenoglu, Hasan

    2012-10-19T23:59:59.000Z

    permanently. This thesis mainly concentrates on the factors affecting the fall rates and how to correlate them in order to derive an applicable test that can be conducted on the field or lab to calculate the terminal velocity of the known epoxy composition...

  18. Molecular extended thermodynamics of rarefied polyatomic gases and wave velocities for increasing number of moments

    SciTech Connect (OSTI)

    Arima, Takashi, E-mail: tks@stat.nitech.ac.jp [Center for Social Contribution and Collaboration, Nagoya Institute of Technology (Japan); Mentrelli, Andrea, E-mail: andrea.mentrelli@unibo.it [Department of Mathematics and Research Center of Applied Mathematics (CIRAM), University of Bologna (Italy); Ruggeri, Tommaso, E-mail: tommaso.ruggeri@unibo.it [Department of Mathematics and Research Center of Applied Mathematics (CIRAM), University of Bologna (Italy)

    2014-06-15T23:59:59.000Z

    Molecular extended thermodynamics of rarefied polyatomic gases is characterized by two hierarchies of equations for moments of a suitable distribution function in which the internal degrees of freedom of a molecule is taken into account. On the basis of physical relevance the truncation orders of the two hierarchies are proven to be not independent on each other, and the closure procedures based on the maximum entropy principle (MEP) and on the entropy principle (EP) are proven to be equivalent. The characteristic velocities of the emerging hyperbolic system of differential equations are compared to those obtained for monatomic gases and the lower bound estimate for the maximum equilibrium characteristic velocity established for monatomic gases (characterized by only one hierarchy for moments with truncation order of moments N) by Boillat and Ruggeri (1997) (?{sub (N)}{sup E,max})/(c{sub 0}) ??(6/5 (N?1/2 )),(c{sub 0}=?(5/3 k/m T)) is proven to hold also for rarefied polyatomic gases independently from the degrees of freedom of a molecule. -- Highlights: •Molecular extended thermodynamics of rarefied polyatomic gases is studied. •The relation between two hierarchies of equations for moments is derived. •The equivalence of maximum entropy principle and entropy principle is proven. •The characteristic velocities are compared to those of monatomic gases. •The lower bound of the maximum characteristic velocity is estimated.

  19. Collisionless magnetic reconnection in the presence of a sheared velocity field

    SciTech Connect (OSTI)

    Faganello, M. [Ecole Polytechnique, LPP, Palaiseau, 91128 (France); Pegoraro, F.; Califano, F. [Department of Physics, University of Pisa and CNISM, Pisa, 56127 (Italy); Marradi, L. [Department of Physics, University of Pisa and CNISM, Pisa, 56127 (Italy)] [Universite de Nice Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, 06304 Nice (France)

    2010-06-15T23:59:59.000Z

    The linear theory of magnetic field lines reconnection in a two-dimensional configuration in the presence of a (Kelvin-Helmholtz stable) sheared velocity field is investigated within a single fluid model, where the onset of magnetic field line reconnection is made possible by the effect of electron inertia in the so called large DELTA{sup '} regime.

  20. On physical interpretation of two dimensional time-correlations regarding time delay velocities and eddy shaping

    SciTech Connect (OSTI)

    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

    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.

  1. Dependence of friction on roughness, velocity, and temperature Martin Dub,2

    E-Print Network [OSTI]

    Grant, Martin

    - faces were discovered long ago by Da Vinci, Amonton, and Coulomb. They found that friction is i, and friction at the macroscopic level is now well understood, for both dry rough 3 and lubricated surfaces 4Dependence of friction on roughness, velocity, and temperature Yi Sang,1 Martin Dubé,2 and Martin

  2. Velocity Fluctuations in Helical Propulsion: How Small Can a Propeller Be

    E-Print Network [OSTI]

    Rangarajan, Govindan

    applied rotating magnetic field. The method of helical propulsion becomes especially important at smallerVelocity Fluctuations in Helical Propulsion: How Small Can a Propeller Be Arijit Ghosh,,# Debadrita propulsion is at the heart of locomotion strategies utilized by various natural and artificial swimmers. We

  3. Reduction in transport by the parallel velocity shear instability due to reversed magnetic shear

    SciTech Connect (OSTI)

    McCarthy, D. R.; Fuselier, E. J.; Sen, S.

    2001-08-01T23:59:59.000Z

    A nonlocal theory of the electrostatic parallel velocity shear instability in a three-dimensional slab with a uniformly sheared magnetic field has been developed. It is shown that in the limit of a weak parallel velocity gradient, the linear growth rate can be increased depending upon the direction of the magnetic shear (s) with respect to the radial curvature of the parallel velocity profile (d{sup 2}v{sub {parallel}}/dx{sup 2}). When these parameters have the same sign, the growth rate can actually be stronger than in the limit of no magnetic shear. In this limit of increased instability, the eigenmode is broadened, thus producing enhanced transport. This effect should be observable when the scale length of the curvature is of order {approx}L{sub s}{rho}{sub s}. For strong parallel velocity gradients that are more typical of flows in tokamaks, the effect of the varying Doppler shift becomes more prominent on the stability of the mode, the net result being that the sensitivity of the growth rates on the sign of the magnetic shear becomes insignificant. This effect, however, is effectively offset when a finite density gradient is included. When the density scale length is of order the scale length of v{sub {parallel}}, the growth rate is moderately reduced, but becomes dependent again upon the sign of the magnetic shear.

  4. Determination of the velocity of an emitter in spaces with affine connections and metrics

    E-Print Network [OSTI]

    Sawa Manoff

    2004-03-04T23:59:59.000Z

    Doppler effect and Hubble effect in different models of space-time related to the space-time velocity of an observer are considered. The Doppler effect and Doppler shift frequency parameter are connected with the kinematic characteristics of the relative velocity and the relative acceleration of the emitter with respect to the observer (detector). The Hubble effect and Hubble shift frequency parameter are considered in analogous way. It is shown that by the use of the variation of the shift frequency parameter during a time period, considered locally in the proper frame of reference of an observer, one can directly determine the radial (centrifugal, centripetal) relative velocity and acceleration as well as the tangential (Coriolis) relative velocity and acceleration of an astronomical object moving relatively to the observer. All results are obtained on purely kinematic basis without taking into account the dynamic reasons for the considered effect. PACS numbers: 98.80.Jk; 98.62.Py; 04.90.+e; 04.80.Cc

  5. Time Series Measurements of Temperature, Current Velocity, and Sediment Resuspension in Saginaw Bay

    E-Print Network [OSTI]

    Time Series Measurements of Temperature, Current Velocity, and Sediment Resuspension in Saginaw Bay and verification. These measurements will be made as part of this project. Measurements of sediment resuspension sediment resuspension in the bay during the spring. Measurements of sediment resuspension are important

  6. Flow Velocity Estimation in Optical Doppler Tomography and A Preliminary Study on Radiation Detection for Hybrid

    E-Print Network [OSTI]

    Piao, Daqing

    Tomography and A Preliminary Study on Radiation Detection for Hybrid Optical Coherence TomographyFlow Velocity Estimation in Optical Doppler Tomography and A Preliminary Study on Radiation Detection for Hybrid Optical Coherence Tomography/Scintigraphy Daqing Piao B.S., Tsinghua University, 1990 M

  7. The mean velocity of two-state models of molecular motor

    E-Print Network [OSTI]

    Yunxin Zhang

    2011-08-09T23:59:59.000Z

    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.

  8. THE MOTION OF MULTIPLE-PHASE JUNCTIONS UNDER PRESCRIBED PHASE-BOUNDARY VELOCITIES

    E-Print Network [OSTI]

    Taylor, Jean

    interface configuration* *s consisting of three half-lines in the plane meeting at a point, or six planar and proved to be complete for which configurations of three half-lines in the 2* *-dimensional plane can between these regions move so that the normal velocity is the mobility times the force * *driving them

  9. Velocity-Difference Induced Focusing of Nucleotides in Capillary Electrophoresis with a

    E-Print Network [OSTI]

    Chen, David D.Y.

    Articles Velocity-Difference Induced Focusing of Nucleotides in Capillary Electrophoresis (CE) with UV detection. The influence of specific analyte properties, such as nucleotide base improvement in concentration sensitiv- ity. The detection limit of 4.0 Ã? 10-8 M for nucleotides can

  10. Neoproterozoic tectonothermal evolution of the Central Eastern Desert, Egypt: a slow velocity tectonic process

    E-Print Network [OSTI]

    Fritz, Harald

    Neoproterozoic tectonothermal evolution of the Central Eastern Desert, Egypt: a slow velocity, University of Assiut, Egypt Received 10 January 2001; received in revised form 24 October 2001; accepted 25 in the Central Eastern Desert of Egypt is constraint by 40 Ar/39 Ar ages of hornblende and muscovite from Meatiq

  11. Experimental constraints on the thermodynamics and sound velocities of hcp-Fe to core pressures

    E-Print Network [OSTI]

    Jackson, Jennifer M.

    that comprises the volume-dependent phonon density of states (DOS) of e-Fe at eleven compression points. From information about the partitioning behavior of iron isotopes in equilibrium processes involving solid e providing a new tight constraint on the density dependence of e-Fe's sound velocities to outer core

  12. Optimization of the structural Gabor functions in a homogeneous velocity model

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    Optimization of the structural Gabor functions in a homogeneous velocity model for a zero-o#11;set functions should be optimized, and the Gabor functions should form a frame. We present a simple attempt functions and the space{wavenumber lattice of their central points are optimized analytically

  13. Miocene faulting at plate tectonic velocity in the Himalaya of central Nepal

    E-Print Network [OSTI]

    Miocene faulting at plate tectonic velocity in the Himalaya of central Nepal Matthew J. Kohna, Tri-Chandra Campus, Ghantaghar, Kathmandu, Nepal, United States Received 7 April 2004; received (MCT) and affiliated faults in central Nepal. Inferred rates were 1.5F0.9 cm/yr (Langtang Thrust, ~19

  14. Seismic Velocity Inversion with Genetic Algorithms Sushil J. Louis Qinxue Chen Satish Pullammanappallil

    E-Print Network [OSTI]

    Louis, Sushil J.

    Seismic Velocity Inversion with Genetic Algorithms Sushil J. Louis Qinxue Chen Satish to compute travel times for seismic waves. However, in practice, we have to solve the inverse problem: travel synthetic seismic models shows that large population sizes are crit- ical to generating good seismic

  15. Seismic Velocity Inversion with Genetic Algorithms Sushil J. Louis Qinxue Chen

    E-Print Network [OSTI]

    Louis, Sushil J.

    Seismic Velocity Inversion with Genetic Algorithms Sushil J. Louis Qinxue Chen Genetic Adaptive­surface models from seismic travel­time data. Given a sub­surface model, the physics of wave propagation through refractive media can be used to compute travel times for seismic waves. How­ ever, in practice, we have

  16. On the definition of velocity in theories with two observer-independent scales

    E-Print Network [OSTI]

    S. Mignemi

    2003-02-10T23:59:59.000Z

    We argue that a consistent definition of the velocity of a particle in generalizations of special relativity with two observer-independent scales should be independent from the mass of the particle. This request rules out the definition $v_i=\\partial p_0/\\partial p_i$, but allows for other definitions proposed in the literature.

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

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    theory I. INTRODUCTION Permanent Magnet Stepper Motors (PMSM's) are widely used in industry for position control, especially in manu- facturing applications. PMSM's are more robust than brush DC motors the question of parameter identification without position or velocity sensors. The es- timation of PMSM

  18. Characterization of Mixing in a Simple Paddle Mixer Using Experimentally Derived Velocity Fields

    E-Print Network [OSTI]

    Bollt, Erik

    to study other mixer configurations (e.g. continuous mixers [5-7], static mixers [8, 9]). Experimental work1 Characterization of Mixing in a Simple Paddle Mixer Using Experimentally Derived Velocity Fields-scale motion in the flow. Batch mixers, similar to food mixers, are a primary method for the processing of many

  19. Isokinetic vs still air sampling of asbestos fiber emission from high-velocity, low-volume vacuum systems

    E-Print Network [OSTI]

    Grabowski, John S

    1979-01-01T23:59:59.000Z

    Jeanne M. Robin, whose love and understanding is the the backbone of this research. TABLE OF CONTENTS Abstract Acknowledgements Dedi cati on List of Tables List of Figures Introduction Literature Review Asbestos Asbestos-Related Diseases...

  20. Seismic surface waves and associated phenomena in a system involving a shallow, thin, high-velocity layer

    E-Print Network [OSTI]

    Egar, Joseph Michael

    1959-01-01T23:59:59.000Z

    Dissertation by JOSEPH MICHAEL EGAR Approved as to style and content by: A ' 1 \\ Co-Chairmen of Committee __ ____________ C 'l .____________________ H??ad of Department of Geology and Geophysics May, 1959 i ii 1 2 3 4 5 7 8 11 13 15 25 25..., p. 193): \\ c o s rH + r H ) + 2 ^ n # V s i o s H - ^ ^ 5s/4 ) f2.-c^ *)(^v/oesi*H + kjf-2sm vH)+ %(Xsin sB -s/&ycossff) \\ = (Z-tffpycfcwcos sH+ % ? s i * s H ) - l - 2 l&(Xsir'ir' H - |r?A-/o?rH) ^ X co s s H + S'A Vsm s h ) 1 2 vkfflk...

  1. The Double Seismic Zone of the Nazca Plate in Northern Chile: High Resolution Velocity Structure, Petrological Implications and

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , Petrological Implications and ThermoMechanical Modelling Catherine Dorbath1 , Muriel Gerbault2 , Gabriel are 20 km apart. Then, the chemical and petrologic characteristics of the oceanic lithosphere associated

  2. Size-velocity correlations in high order moment methods for polydisperse evaporating sprays: modelling and numerical issues

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , such as internal combustion engine ([1, 2] and references therein), gas turbine [3] or rocket booster [4]. Those, Laboratoire d'Energ´etique mol´eculaire et macroscopique, combustion, Grande Voie des Vignes, 92295 Chatenay emissions...). The description of a disperse phase may rely on a population balance equation (PBE

  3. High resolution laser induced fluorescence Doppler velocimetry utilizing saturated absorption spectroscopy

    SciTech Connect (OSTI)

    Aramaki, Mitsutoshi [Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603 (Japan); Ogiwara, Kohei; Etoh, Shuzo [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580 (Japan); Yoshimura, Shinji [National Institute for Fusion Science, Toki 509-5292 (Japan); Tanaka, Masayoshi Y. [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga 816-8580 (Japan)

    2009-05-15T23:59:59.000Z

    A high resolution laser induced fluorescence (LIF) system has been developed to measure the flow velocity field of neutral particles in an electron-cyclotron-resonance argon plasma. The flow velocity has been determined by the Doppler shift of the LIF spectrum, which is proportional to the velocity distribution function. Very high accuracy in velocity determination has been achieved by installing a saturated absorption spectroscopy unit into the LIF system, where the absolute value and scale of laser wavelength are determined by using the Lamb dip and the fringes of a Fabry-Perot interferometer. The minimum detectable flow velocity of a newly developed LIF system is {+-}2 m/s, and this performance remains unchanged in a long-time experiment. From the radial measurements of LIF spectra of argon metastable atoms, it is found that there exists an inward flow of neutral particles associated with neutral depletion.

  4. A Qualitative Investigation of Deposition Velocities of a Non-Newtonian Slurry in Complex Pipeline Geometries

    SciTech Connect (OSTI)

    Yokuda, Satoru T.; Poloski, Adam P.; Adkins, Harold E.; Casella, Andrew M.; Hohimer, Ryan E.; Karri, Naveen K.; Luna, Maria; Minette, Michael J.; Tingey, Joel M.

    2009-05-11T23:59:59.000Z

    The External Flowsheet Review Team (EFRT) has identified the issues relating to the Waste Treatment and Immobilization Plant (WTP) pipe plugging. Per the review’s executive summary, “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.” To evaluate the potential for plugging, testing was performed to determine critical velocities for the complex WTP piping layout. Critical velocity is defined as the point at which a moving bed of particles begins to form on the pipe bottom during slurry-transport operations. Pressure drops across the fittings of the test pipeline were measured with differential pressure transducers, from which the critical velocities were determined. A WTP prototype flush system was installed and tested upon the completion of the pressure-drop measurements. We also provide the data for the overflow relief system represented by a WTP complex piping geometry with a non-Newtonian slurry. A waste simulant composed of alumina (nominally 50 ?m in diameter) suspended in a kaolin clay slurry was used for this testing. The target composition of the simulant was 10 vol% alumina in a suspending medium with a yield stress of 3 Pa. No publications or reports are available to confirm the critical velocities for the complex geometry evaluated in this testing; therefore, for this assessment, the results were compared to those reported by Poloski et al. (2008) for which testing was performed for a straight horizontal pipe. The results of the flush test are compared to the WTP design guide 24590-WTP-GPG-M-0058, Rev. 0 (Hall 2006) in an effort to confirm flushing-velocity requirements.

  5. Fourier method in the determination of rotational velocities in OB stars

    E-Print Network [OSTI]

    S. Simón-Díaz; A. Herrero

    2007-03-09T23:59:59.000Z

    We present a comprehensive study that applies the Fourier transform to a sample of O and early B-type stars (either dwarfs, giants, or supergiants) to determine their projected rotational velocities, compare with previous values obtained with other methods, and seek for evidence of extra broadening in the spectral lines The Fourier technique, extensively used in the study of cooler stars, has remained only marginally applied for the case of early-type stars. The comparison of \\vsini values obtained through the \\ft and \\fwhm methods shows that the \\fwhm technique must be used with care in the analysis of OB giants and supergiants, and when it is applied to \\ion{He}{i} lines. Contrarily, the \\ft method appears to be a powerful tool to derive reliable projected rotational velocities, and separate the effect of rotation from other broadening mechanisms present in these stars. The analysis of the sample of OB stars shows that while dwarfs and giants display a broad range of projected rotational velocities, from less than 30 up to 450 \\kms, supergiants have in general values close to or below 100 \\kms. The analysis has also definitely shown that while the effect of extra broadening is negligible in OB dwarfs, it is clearly present in supergiants. When examining the behavior of the projected rotational velocities with the stellar parameters and across the HR diagram, we conclude, in agreement with previous researchers, that the rotational velocity should decrease when the stars evolve. On the contrary, macroturbulence may be constant, resulting therefore in an increasing importance as compared to rotation when the stars evolve.

  6. Seismic velocity estimation and time to depth conversion of time-migrated images Maria Cameron, University of California at Berkeley, Sergey Fomel, University of Texas at Austin, and

    E-Print Network [OSTI]

    Sethian, James A.

    Seismic velocity estimation and time to depth conversion of time-migrated images Maria Cameron migrated seismic images and show that the Dix velocities estimated from time migration velocities are the true seismic velocities divided by the ge- ometrical spreading of image rays. We pose an inverse

  7. A Spatially Resolving X-ray Crystal Spectrometer for Measurement of Ion-temperature and Rotation-velocity Profiles on the AlcatorC-Mod Tokamak

    SciTech Connect (OSTI)

    Hill, K. W.; Bitter, M. L.; Scott, S. D.; Ince-Cushman, A.; Reinke, M.; Rice, J. E.; Beiersdorfer, P.; Gu, M. F.; Lee, S. G.; Broennimann, C. H.; Eikenberry, E. F.

    2009-03-24T23:59:59.000Z

    A new spatially resolving x-ray crystal spectrometer capable of measuring continuous spatial profiles of high resolution spectra (?/d? > 6000) of He-like and H-like Ar K? lines with good spatial (~1 cm) and temporal (~10 ms) resolutions has been installed on the Alcator C-Mod tokamak. Two spherically bent crystals image the spectra onto four two-dimensional Pilatus II pixel detectors. Tomographic inversion enables inference of local line emissivity, ion temperature (Ti), and toroidal plasma rotation velocity (v?) from the line Doppler widths and shifts. The data analysis techniqu

  8. A laser frequency comb that enables radial velocity measurements with a precision of 1 cm s$^{-1}$

    E-Print Network [OSTI]

    Chih-Hao Li; Andrew J. Benedick; Peter Fendel; Alexander G. Glenday; Franz X. Kaertner; David F. Phillips; Dimitar Sasselov; Andrew Szentgyorgyi; Ronald L. Walsworth

    2008-04-07T23:59:59.000Z

    Searches for extrasolar planets using the periodic Doppler shift of stellar spectral lines have recently achieved a precision of 60 cm/s (ref 1), which is sufficient to find a 5-Earth-mass planet in a Mercury-like orbit around a Sun-like star. To find a 1-Earth-mass planet in an Earthlike orbit, a precision of 5 cm/s is necessary. The combination of a laser frequency comb with a Fabry-Perot filtering cavity has been suggested as a promising approach to achieve such Doppler shift resolution via improved spectrograph wavelength calibration, with recent encouraging results. Here we report the fabrication of such a filtered laser comb with up to 40- GHz (1-A) line spacing, generated from a 1- GHz repetition-rate source, without compromising long-term stability, reproducibility or spectral resolution. This wide-line-spacing comb, or `astro-comb', is well matched to the resolving power of high-resolution astrophysical spectrographs. The astro-comb should allow a precision as high as 1 cm/s in astronomical radial velocity measurements.

  9. Heavy ion fusion science research for high energy density physics and fusion applications

    E-Print Network [OSTI]

    Logan, B.G.

    2007-01-01T23:59:59.000Z

    cost direct plasma MHD direct conversion [38], as well as toT-lean targets and direct conversion for heavy ion fusion. [conversion loss of beam energy into x-rays. High ablation velocities with heavy ion direct

  10. ccsd-00000648(version1):29Sep2003 Damping rates of the atomic velocity in Sisyphus cooling

    E-Print Network [OSTI]

    an impressive progress in laser cooling techniques, and nowdays it is possible to prepare and manipulate veryccsd-00000648(version1):29Sep2003 Damping rates of the atomic velocity in Sisyphus cooling Laurent of the damping process of the atomic velocity in Sisyphus cooling. The relaxation rates of the atomic kinetic

  11. Settling Velocities of Fractal C L I F F O R D P . J O H N S O N ,

    E-Print Network [OSTI]

    data and Stokes' law. Introduction Particle transport by gravitational sedimentation is im- portant in settling velocity calculations using Stokes' law. In order to demonstrate that settling velocity models thosepredictedusingeitheranimpermeablesphere model (Stokes' law) or a permeable sphere model that specified aggregate permeability

  12. Boundary problems for the one-dimensional kinetic equation with the collisional frequence proportional to the module velocity of molecules

    E-Print Network [OSTI]

    A. V. Latyshev; A. A. Yushkanov

    2014-06-08T23:59:59.000Z

    For the one-dimensional linear kinetic equations with collisional frequency of the molecules, proportional to the module velocity of molecules, analytical solutions of problems about temperature jump and weak evaporation (condensation) in rarefied gas are received. Quantities of temperature and concentration jumps are found. Distributions of concentration, mass velocity and temperature are constructed. Necessary numerical calculations and graphic researches are done.

  13. Methods for passivating silicon devices at low temperature to achieve low interface state density and low recombination velocity while preserving carrier lifetime

    DOE Patents [OSTI]

    Chen, Zhizhang (Duluth, GA); Rohatgi, Ajeet (Marietta, GA)

    1995-01-01T23:59:59.000Z

    A new process has been developed to achieve a very low SiO.sub.x /Si interface state density D.sub.it, low recombination velocity S (<2 cm/s), and high effective carrier lifetime T.sub.eff (>5 ms) for oxides deposited on silicon substrates at low temperature. The technique involves direct plasma-enhanced chemical vapor deposition (PECVD), with appropriate growth conditions, followed by a photo-assisted rapid thermal annealing (RTA) process. Approximately 500-A-thick SiO.sub.x layers are deposited on Si by PECVD at 250.degree. C. with 0.02 W/cm.sup.-2 rf power, then covered with SiN or an evaporated thin aluminum layer, and subjected to a photo-assisted anneal in forming gas ambient at 350.degree. C., resulting in an interface state density D.sub.it in the range of about 1-4.times.10.sup.10 cm.sup.-2 eV.sup.-1, which sets a record for the lowest interface state density D.sub.it for PECVD oxides fabricated to date. Detailed analysis shows that the PECVD deposition conditions, photo-assisted anneal, forming gas ambient, and the presence of an aluminum layer on top of the oxides during the anneal, all contributed to this low value of interface state density D.sub.it. Detailed metal-oxide semiconductor analysis and model calculations show that such a low recombination velocity S is the result of moderately high positive oxide charge (5.times.10.sup.11 -1.times.10.sup.12 cm.sup.-2) and relatively low midgap interface state density (1.times.10.sup.10 -4.times.10.sup.10 cm.sup.-2 eV.sup.-1). Photo-assisted anneal was found to be superior to furnace annealing, and a forming gas ambient was better than a nitrogen ambient for achieving a very low surface recombination velocity S.

  14. High gas flow alpha detector

    DOE Patents [OSTI]

    Bolton, R.D.; Bounds, J.A.; Rawool-Sullivan, M.W.

    1996-05-07T23:59:59.000Z

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors. 4 figs.

  15. High gas flow alpha detector

    DOE Patents [OSTI]

    Bolton, Richard D. (Los Alamos, NM); Bounds, John A. (Los Alamos, NM); Rawool-Sullivan, Mohini W. (Los Alamos, NM)

    1996-01-01T23:59:59.000Z

    An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors.

  16. Vectorial velocity filter for ultracold neutrons based on a surface-disordered mirror system

    E-Print Network [OSTI]

    L. A. Chizhova; S. Rotter; T. Jenke; G. Cronenberg; P. Geltenbort; G. Wautischer; H. Filter H. Abele; J. Burgdörfer

    2014-03-19T23:59:59.000Z

    We perform classical three-dimensional Monte Carlo simulations of ultracold neutrons scattering through an absorbing-reflecting mirror system in the Earth's gravitational field. We show that the underlying mixed phase space of regular skipping motion and random motion due to disorder scattering can be exploited to realize a vectorial velocity filter for ultracold neutrons. The absorbing-reflecting mirror system proposed allows beams of ultracold neutrons with low angular divergence to be formed. The range of velocity components can be controlled by adjusting the geometric parameters of the system. First experimental tests of its performance are presented. One potential future application is the investigation of transport and scattering dynamics in confined systems downstream of the filter.

  17. Comment on "Cyclotron resonance study of the electron and hole velocity in graphene monolayers"

    E-Print Network [OSTI]

    S. C. Tiwari

    2007-05-26T23:59:59.000Z

    In this comment it is pointed out that the electron velocity of the same order as observed in graphene had been measured in GaAs submicron devices long ago. Particle- antiparticle asymmetry related with electron and hole effective masses in graphene seems puzzling as hole in a condensed matter system cannot be treated as anti-electron. It is argued that there should be a universal electrodynamics for QHE and superconductivity. In this context attention is drawn to the new approach based on massless electron and the interpretation that magnetic field represents angular momentum of the photon fluid. Measurement of electron velocity in graphene and GaAs in parallel is suggested for testing the massless electrodynamics.

  18. Constraints on H_0 from the Central Velocity Dispersions of Lens Galaxies

    E-Print Network [OSTI]

    Aaron J. Romanowsky; Christopher S. Kochanek

    1998-11-21T23:59:59.000Z

    We employ Schwarzschild's method of orbit modeling to constrain the mass profiles of the central lens galaxies in Q0957+561 and PG 1115+080. We combine the measured central projected stellar velocity dispersions of these galaxies with the self-similar radial profiles of the rms velocity and of the Gauss-Hermite moment h_4 observed in nearby galaxies for 0 < R < 2 R_eff. For Q0957+561, we find a 16% uncertainty in the galaxy mass, and formal 2-sigma limits on the Hubble constant of H_0 = (61 +13/-15) km/s/Mpc. For PG 1115+080, we find that none of the viable lens models can be ruled out, so that H_0 is not yet strongly constrained by this system.

  19. Wave Packet for Massless Fermions and its Implication to the Superluminal Velocity Statistics of Neutrino

    E-Print Network [OSTI]

    Kelin Wang; Zexian Cao

    2012-01-06T23:59:59.000Z

    Non-dispersive wave packet for massless fermions is formulated on the basis of squeezed coherent states that are put in a form of common eigenfunction for the Hamiltonian and the helicity operator, starting from the Dirac equation. The wave packet thus constructed is demonstrated to propagate at a constant velocity as that of light. This explicit expression of wave packet for the massless fermions can facilitate theoretical analysis of problems where a wave packet is of formal significance. Furthermore, extensive wave packet may result in a superluminal velocity statistics if determined from the time-of-flight measurement, as recently done on muon neutrinos, when a threshold particle flux or energy transfer, which is eventually referred to the propagation of wave packet, to invoke a detection event is assumed.

  20. Lie-admissible approach to ''extended relativity. '' I. Nonlinear velocity, mass, and charge transformations

    SciTech Connect (OSTI)

    Animalu, A.O.E.

    1987-11-01T23:59:59.000Z

    A new approach to the ''extended relativity'' principle proposed by Recami, Mignani, and others, in which the speed of light (c) is invariant with respect to both subluminal (vc) linear generalized Lorentz transformations in vacuum, is presented, in order to take into account some novel nonlinear velocity transformations (v, V) ..-->.. (v', V'), associated with changes in motion at the interface between vacuum and a deformable hadronic medium, envisaged in Santilli's notion of quarks as mutations of physical leptons (''eletons'') inside hadrons. The new approach demands a generalization of the usual ralation (vV = c/sup 2/) between subluminal and superluminal inertial frames or objects to the (Lie-admissible) form (vV = c/sup 2/ = V'/sup 2/-v'/sup 2/), which is tantamount to a principle of relativistic invariance in velocity space.

  1. GAS EXCITATION IN ULIRGs: MAPS OF DIAGNOSTIC EMISSION-LINE RATIOS IN SPACE AND VELOCITY

    SciTech Connect (OSTI)

    Soto, Kurt T.; Martin, Crystal L. [Physics Department, University of California, Santa Barbara, CA 93106-9530 (United States)

    2012-11-15T23:59:59.000Z

    Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of H{alpha}, [N II], [S II], [O I], H{beta}, and [O III] are resolved and fit jointly with common velocity components. Diagnostic ratios of these line fluxes are presented in a series of plots, showing how the Doppler shift, line width, gas excitation, and surface brightness change with velocity at fixed position and also with distance from the nucleus. One general characteristic of these spectra is the presence of shocked gas extending many kiloparsecs from the nucleus. In some systems, the rotation curves of the emitting gas indicate motions that suggest gas disks, which are most frequent at early merger stages. At these early merger stages, the emission line ratios indicate the presence of shocked gas, which may be triggered by the merger event. We also report the general characteristics of the integrated spectra.

  2. Measurements of velocity shear and ion viscosity profile in a magnetohydrodynamic plasma jet

    SciTech Connect (OSTI)

    Dorf, L. A.; Intrator, T.; Sun, X.; Hendryx, J.; Wurden, G. A.; Furno, I; Lapenta, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2010-10-15T23:59:59.000Z

    Time-dependent, two-dimensional profiles of the axial flow velocity, density, electron temperature, and magnetic field components are measured at two axial locations in a screw pinch plasma column of the reconnection scaling experiment. The results show that the ion momentum flux for a given column radius is dissipated by the ion-ion Coulomb scattering viscosity due to a significant radial shear of the axial velocity. By comparing the terms of the magnetohydrodynamic momentum balance equation, radial profile of ion viscosity is determined. Chord-integrated ion temperature measurements performed at several radial locations using Doppler broadening spectroscopy show ion temperature of about 1 eV. Measured ion viscosity agrees within a factor of 2 with the classical Braginskii expectations.

  3. Particle velocity based universal algorithm for numerical simulation of hydraulic fractures

    E-Print Network [OSTI]

    Wrobel, Michal

    2014-01-01T23:59:59.000Z

    In the paper, we propose a new effective mathematical formulation and resulting universal numerical algorithm capable of tackling various HF models in the framework of a unified approach. The presented numerical scheme is not limited to any particular elasticity model or crack propagation regime. Its basic assumptions are: i) proper choice of independent and dependent variables (with the direct utilization of a new one - the reduced particle velocity), ii) tracing the fracture front by use of the speed equation which can be integrated in a closed form and sets an explicit relation between the crack propagation speed and the coefficients in the asymptotic expansion of the crack opening, iii) proper regularization techniques, iv) improved temporal approximation, v) modular algorithm architecture. The application of the new dependent variable, the reduced particle velocity, instead of the usual fluid flow rate, facilitates the computation of the crack propagation speed from the local relation based on the speed ...

  4. Magnetic Resonance Flow Velocity and Temperature Mapping of a Shape Memory Polymer Foam Device

    SciTech Connect (OSTI)

    Small IV, W; Gjersing, E; Herberg, J L; Wilson, T S; Maitland, D J

    2008-10-29T23:59:59.000Z

    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.

  5. Variation of seismic-wave velocities in westerly granite under stress

    E-Print Network [OSTI]

    Al-Shaibani, Abdulaziz Muhareb

    1994-01-01T23:59:59.000Z

    -wave Results. S-wave Results. SUMMARY. REFERENCES. . . . :. 10 . . . . 13 . . . . . . . . 17 . . . . . 21 . . . . . 24 . . . . . 24 . . . . . 28 . . . . . 35 . . . . . . . 36 LIST OF TABLES Page TABLE la. Compressional-wave velocities, Vp.... . 17 Figure 7 Crosscorrelation between two P-wave traces along one direction at two different pressure levels to determine the relative time delays. . . . . 20 Figure 8. (a, b and c). P-wave traces measured at the center of the faces along x-, y...

  6. Critical Superfluid Velocity in a Trapped Dipolar Gas Ryan M. Wilson,* Shai Ronen,

    E-Print Network [OSTI]

    Wilson, Ryan M.

    of sound in liquid helium, but is smaller due to the existence of an anomalously low-energy roton mode. In particular, their critical velocity is nomi- nally given by the speed of sound in the center of the gas numbers: 67.85.Ã?d, 03.75.Kk, 47.37.+q Liquid 4 He was the first experimentally accessible sys- tem

  7. Derivation and New Interpretation of the Lorentz Transformations and Einstein's Theorem of Velocity Addition

    E-Print Network [OSTI]

    Vladimir T. Granik; Alex Granik

    2013-03-27T23:59:59.000Z

    It is traditionally believed that the Lorentz transformations (LT) and Einstein's theorem of velocity addition (ETVA), underlying special relativity, cannot be obtained from non-relativistic (classical) mechanics. In the present paper it is shown, however, that both the LT and the ETVA are derivable within the framework of classical kinematics if the speeds of material points are bounded above by a certain universal limit $c_+$ which can coincide with the speed of light $c$ in a vacuum.

  8. Möbius Transformation and Einsten Velocity Addition in the Hyperbolic Geometry of Bolyai and Lobachevsky

    E-Print Network [OSTI]

    Abraham A. Ungar

    2013-03-19T23:59:59.000Z

    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.

  9. Relativistic velocity addition law derived from a machine gun analogy and time dilation only

    E-Print Network [OSTI]

    Bernhard Rothenstein; Stefan Popescu

    2007-03-15T23:59:59.000Z

    We consider a scenario that involves a machine gun, the bullets it fires and a moving target, considered from the rest frame of the machine gun and from the rest frame of the target respectively. Involving the special relativity via its two postulates and the time dilation formula we derive the relativistic velocity addition law showing that it leads to the Lorentz transformations for the space-time coordinates of the same event.

  10. The Effects of Indoor Air Velocity on Occupant Thermal Comfort in Winter

    E-Print Network [OSTI]

    Wang, J.; Chen, L.

    2006-01-01T23:59:59.000Z

    ICEBO2006, Shenzhen, China Maximize Comfort: Temperature, Humidity, and IAQ, Vol. I-2-5 The Effects of Indoor Air Velocity on Occupant Thermal Comfort in Winter Jiaolin Wang Lu Chen Postgrauate Master... surface temperature decline to reduce the body?s heat loss. Meanwhile shudder will promote the body?s heat production. So the temperature of organism doesn?t drop with decline of the environmental temperature. But if organism stays at cool environment...

  11. Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory

    E-Print Network [OSTI]

    J. T. Wright

    2005-05-11T23:59:59.000Z

    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.

  12. Variables and units in Ocean 420 u zonal velocity (east-west) m/s

    E-Print Network [OSTI]

    Thompson, LuAnne

    speed m/s Cg group velocity m/s k wave number 1/m frequency 1/s wavelength m T period s kinematic mixed-layer and water below C E Energy density in surface gravity wave J/m 2 #12;Some constants k Von surface height m g gravitational constant m/s 2 a amplitude of wave in sea surface height m f Coriolis

  13. Estimation of Velocity Distribution and Suspended Sediment Discharge in Open Channels Using Entropy

    E-Print Network [OSTI]

    Cui, Huijuan

    2011-08-08T23:59:59.000Z

    of entropy.?????.?...??????? 99 7.1.4 Cumulative distribution function.?????.?????.. 100 7.1.5 General sediment concentration distribution?.?????.. 102 7.1.6 Dimensionless parameter N?.???????????? 103 7.2 Application of sediment distribution...?????..??????...?????... 44 vii Page 4.2.1 Setting a coordinate system?..??????...????? 44 4.2.2 Cumulative distribution function?????...?????. 44 4.2.3 Verification of cumulative distribution function?????. 45 5 . DERIVATION OF VELOCITY DISTRIBUTION...

  14. Interrelationships between air velocity and natural wet-bulb thermometer response

    E-Print Network [OSTI]

    Jones, Nathan Glenn

    1983-01-01T23:59:59.000Z

    INTERRELATIONSHIPS BETWEEN AIR VFLOCITY ANO NATURAL WET-BULB THERMOMETER RESPONSE A Thesis by NATHAN GLENN JONES Submitted to the Graduate Colleqe of Texas ASM University i n partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE AUGUST 1983 Major Subject: Industrial Hygiene INTERRELATIONSHIPS BETWEEN AIR VELOCITY AND NATURAL WET-BULB THERMOMETER RESPONSE A Thesis by NATHAN GLENN JONES Approved as to style an content by: airman o ommittee er Member ~~' A~ Member...

  15. Full-field velocity measurements of single and two phase flows using digital pulsed laser velocimetry

    E-Print Network [OSTI]

    Canaan, Robert Ernst

    1990-01-01T23:59:59.000Z

    particles. The use of a cylindrical constant heat flux emitting conductor enabled full-field velocity measurement of unsteady natural convective flows over a wide range of single phase flow regimes. The method was additionally extended to the measurement... and will utilize a constant heat flux emitting electrical conductor in order to represent a simple model of a nuclear reactor fuel element vertically positioned within a rectangular coolant channel. Natural convective cooling is of particularly recent concern...

  16. Effect of ion excape velocity and conversion surface material on H- production

    SciTech Connect (OSTI)

    Johnson, Kenneth F [Los Alamos National Laboratory; Tarvainen, Olli A [Los Alamos National Laboratory; Geros, E. [Los Alamos National Laboratory; Stelzer, J. [Los Alamos National Laboratory; Rouleau, G. [Los Alamos National Laboratory; Kalvas, T. [UNIV OF JYVASKYLA; Komppula, J. [UNIV OF JYASKYLA; Carmichael, J. [ORNL

    2010-10-05T23:59:59.000Z

    According to generally accepted models surface production of negative ions depends on ion escape velocity and work function of the surface. We have conducted an experimental study addressing the role of the ion escape velocity on H{sup -} production. A converter-type ion source at Los Alamos Neutron Science Center was employed for the experiment. The ion escape velocity was changed by varying the bias voltage of the converter electrode. It was observed that due to enhanced stripping of H{sup -} no direct gain of extracted beam current can be achieved by increasing the converter voltage. At the same time the conversion efficiency of H{sup -} was observed to vary with converter voltage and follow the existing theories in qualitative manner. We discuss the role of surface material on H{sup -} formation probability and present calculations predicting relative H{sup -} yields from different cesiated surfaces. These calculations are compared with experimental observations from different types of H{sup -} ion sources. The effects caused by varying cesium coverage are also discussed. Finally, we present a novel idea of utilizing materials exhibiting so-called negative electron affinity in H{sup -}/D{sup -} production under UV-light exposure.

  17. VELOCITY FIELD OF COMPRESSIBLE MAGNETOHYDRODYNAMIC TURBULENCE: WAVELET DECOMPOSITION AND MODE SCALINGS

    SciTech Connect (OSTI)

    Kowal, Grzegorz; Lazarian, A., E-mail: kowal@astro.wisc.ed, E-mail: lazarian@astro.wisc.ed [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States)

    2010-09-01T23:59:59.000Z

    We study compressible magnetohydrodynamic turbulence, which holds the key to many astrophysical processes, including star formation and cosmic-ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid, we use wavelet decomposition of the turbulent velocity field into Alfven, slow, and fast modes, which presents an extension of the Cho and Lazarian decomposition approach based on Fourier transforms. The wavelets allow us to follow the variations of the local direction of the magnetic field and therefore improve the quality of the decomposition compared to the Fourier transforms, which are done in the mean field reference frame. For each resulting component, we calculate the spectra and two-point statistics such as longitudinal and transverse structure functions as well as higher order intermittency statistics. In addition, we perform a Helmholtz- Hodge decomposition of the velocity field into incompressible and compressible parts and analyze these components. We find that the turbulence intermittency is different for different components, and we show that the intermittency statistics depend on whether the phenomenon was studied in the global reference frame related to the mean magnetic field or in the frame defined by the local magnetic field. The dependencies of the measures we obtained are different for different components of the velocity; for instance, we show that while the Alfven mode intermittency changes marginally with the Mach number, the intermittency of the fast mode is substantially affected by the change.

  18. A clear age-velocity dispersion correlation in Andromeda's stellar disk

    E-Print Network [OSTI]

    Dorman, Claire E; Seth, Anil C; Weisz, Daniel R; Bell, Eric F; Dalcanton, Julianne J; Gilbert, Karoline M; Hamren, Katherine M; Lewis, Alexia R; Skillman, Evan D; Toloba, Elisa; Williams, Benjamin F

    2015-01-01T23:59:59.000Z

    The stellar kinematics of galactic disks are key to constraining disk formation and evolution processes. In this paper, for the first time, we measure the stellar age-velocity dispersion correlation in the inner 20 kpc (3.5 disk scale lengths) of M31 and show that it is dramatically different from that in the Milky Way. We use optical Hubble Space Telescope/Advanced Camera for Surveys photometry of 5800 individual stars from the Panchromatic Hubble Andromeda Treasury (PHAT) survey and Keck/DEIMOS radial velocity measurements of the same stars from the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) survey. We show that the average line-of-sight velocity dispersion is a steadily increasing function of stellar age exterior to R=10 kpc, increasing from 30 km/s for the young upper main sequence stars to 90 km/s for the old red giant branch stars. This monotonic increase implies that a continuous or recurring process contributed to the evolution of the disk. Both the slope and normaliz...

  19. Thermal conduction by dark matter with velocity and momentum-dependent cross-sections

    E-Print Network [OSTI]

    Aaron C. Vincent; Pat Scott

    2014-04-23T23:59:59.000Z

    We use the formalism of Gould and Raffelt to compute the dimensionless thermal conduction coefficients for scattering of dark matter particles with standard model nucleons via cross-sections that depend on the relative velocity or momentum exchanged between particles. Motivated by models invoked to reconcile various recent results in direct detection, we explicitly compute the conduction coefficients $\\alpha$ and $\\kappa$ for cross-sections that go as $v_{\\rm rel}^2$, $v_{\\rm rel}^4$, $v_{\\rm rel}^{-2}$, $q^2$, $q^4$ and $q^{-2}$, where $v_{\\rm rel}$ is the relative DM-nucleus velocity and $q$ is the momentum transferred in the collision. We find that a $v_{\\rm rel}^{-2}$ dependence can significantly enhance energy transport from the inner solar core to the outer core. The same can true for any $q$-dependent coupling, if the dark matter mass lies within some specific range for each coupling. This effect can complement direct searches for dark matter; combining these results with state-of-the-art Solar simulations should greatly increase sensitivity to certain DM models. It also seems possible that the so-called Solar Abundance Problem could be resolved by enhanced energy transport in the solar core due to such velocity- or momentum-dependent scatterings.

  20. Electrostatic mode associated with the pinch velocity in reversed field pinch simulations

    SciTech Connect (OSTI)

    Delzanno, Gian Luca [Los Alamos National Laboratory (LANL); Chacon, Luis [Oak Ridge National Laboratory (ORNL); Finn, John M. [Los Alamos National Laboratory (LANL)

    2008-01-01T23:59:59.000Z

    The existence of a new phenomenon in reversed field pinch (RFP) simulations related to the equilibrium pinch flow is discussed. This behavior is due to the inward equilibrium flow, but is strongly affected by boundary conditions on the perturbed azimuthal flow. It is important to understand and control this mechanism in single helicity simulations of RFPs. This mechanism can be explained in terms of an electrostatic instability related to a mode which can occur in fluid dynamics. In a simple linear model, it is shown that the mode, which is related to the inward advection of angular momentum from the edge, can be stabilized by using homogeneous Dirichlet (no-slip) boundary conditions at the wall. Behavior due to this mode is present in nonlinear simulations with zero-viscous-stress boundary conditions on the tangential velocity at the wall and, even in the presence of the usual magnetohydrodynamic modes, this mode can dominate the nonlinear dynamics of the velocity. In nonlinear simulations with Dirichlet boundary conditions on the tangential velocity, behavior associated with this electrostatic mode is not observed.