4,033 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Velocity"  
Results: 1 - 24 next
open access

Foundations of VISAR analysis.

Description: The Velocity Interferometer System for Any Reflector (VISAR) is a widely used diagnostic at Sandia National Laboratories. Although the operating principles of the VISAR are well established, recently deployed systems (such as the fast push-pull and air delay VISAR) require more careful consideration, and many common assumptions about VISAR are coming into question. This report presents a comprehensive review of VISAR analysis to address these issues. Detailed treatment of several interferometer… more
Date: June 1, 2006
Creator: Dolan, Daniel H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

SIRHEN : a data reduction program for photonic Doppler velocimetry measurements.

Description: SIRHEN (Sandia InfraRed HEtrodyne aNalysis) is a program for reducing data from photonic Doppler velocimetry (PDV) measurements. SIRHEN uses the short-time Fourier transform method to extract velocity information. The program can be run in MATLAB (2008b or later) or as a Windows executable. This report describes the new Sandia InfraRed HEtrodyne aNalysis program (SIRHEN; pronounced 'siren') that has been developed for efficient and robust analysis of PDV data. The program was designed for easy … more
Date: June 1, 2010
Creator: Dolan, Daniel H., III & Ao, Tommy
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Nature of Accelerating Modes in PBG Fibers

Description: Transverse magnetic (TM) modes with phase velocities at or just below the speed of light, c, are intended to accelerate relativistic particles in hollow-core, photonic band gap (PBG) fibers. These are so-called 'surface defect modes', being lattice modes perturbed by the defect to have their frequencies shifted into the band gap, and they can have any phase velocity. PBG fibers also support so-called 'core defect modes' which are characterized as having phase velocities always greater than c an… more
Date: May 19, 2011
Creator: Noble, TRobert J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

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

Description: 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 vφ on C-Mod. The imaging XCS design has also been adopted … more
Date: January 29, 2008
Creator: Hill, K. W.; Broennimann, C. H.; Eikenberry, E. F.; Ince-Cushman, A.; Lee, S. G.; Rice, J. E. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Controlled Velocity Testing of an 8-kW Wind Turbine

Description: This paper describes a case study of the controlled-velocity test of an 8-kW wind turbine. The turbine was developed in response to the U.S. Department of Energy's small wind turbine program. As background, the prototype development is discussed. The turbine mechanical and electrical components are described. The turbine was tested on a flatbed truck and driven down an airfield runway at constant relative wind speed. Horizontal furling was used to control over-speed. Various parameters were cha… more
Date: July 31, 2001
Creator: Larwood, S.; Sencenbaugh, J. & Acker, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Differential Group-Velocity Detection of Fluid Paths Leland Timothy Long

Description: The objective of differential surface-wave interpretation is to identify and locate temporal perturbations in the shear-wave velocity. Perturbations in phase velocity are created when the stress and/or fluid content of soils changes, such as in pumping to remove or flush out contaminants. Differential surface wave analysis is a potential method to track the movement of fluids during remediation programs. This proposal is to develop and test this new technology to aid in the selection and design… more
Date: June 1, 2003
Creator: Long, Leland Timothy
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Nonlinear pulse propagation and phase velocity of laser-driven plasma waves

Description: Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the ene… more
Date: March 25, 2011
Creator: Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric & Leemans, Wim
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CHARICE version 1.1 update.

Description: CHARICE (CHARacteristics-based inverse analysis of Isentropic Compression Experiments) is a computer application, previously documented in SAND2007-4948, that analyzes velocity waveform data from ramp-wave experiments to determine a material's quasi-isentropic loading response in stress and density using an iterative characteristics-based approach. This short report documents only the changes in CHARICE release version 1.1 relative to release version 1.0, and is not intended to stand alone. CHA… more
Date: October 1, 2008
Creator: Davis, Jean-Paul
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

LOW VELOCITY IMPACT RESPONSE OF A LAMINATED COMPOSITE TUBE WITH A METALLIC BUMPER LAYER

Description: A thin metallic sheet was bonded to the outer surface of a laminated composite curved beam as a bumper layer. It was believed that a metallic bumper layer such as an aluminum thin sheet would be able to intercept any lateral impacting force and absorb impact energy through plastic deformation. Since aluminum is comparatively light weight, a thin sheet will not result in a significant increase in structural weight. Results showed that impact damage occurred primarily in the bumper layer, thereby… more
Date: July 1, 2006
Creator: Ibekwe, S.I.; Li, G.; Pang, S.S. & and Smith, B. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Simulation Modeling of an Enhanced Low-Emission Swirl-Cascade Burner

Description: Based on the physical and computational models outlined in the previous technical progress reports, Natural gas jet diffusion flames in baseline, cascade, swirl, and swirlcascade burners were numerically modeled. The thermal, composition, and flow (velocity) fields were simulated. The temperature, CO{sub 2} and O{sub 2} concentrations, as well as the axial and radial velocity profiles were computed and analyzed. The numerical results showed that swirl and cascade burners have a more efficient f… more
Date: April 1, 2004
Creator: Qubbaj, Ala
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A velocity map imaging spectrometer for electron?ion and ion?ion coincidence experiments with synchrotron radiation

Description: We have built a velocity imaging (VMI) spectrometer optimized for angle-resolved photoionization experiments with synchrotron radiation (SR) in the VUV and soft X-tay range. The spectrometer is equiped with four electrostatic lenses that focus the charged photoionization products onto a position-sensitive multi-hit delay-line anode. The use of two additional electrostatic lens elements as compared to the standard design of Eppink and Parker [T.J.B. Eppink and D.H. Parker, Rev. Sci. Instrum. 68 … more
Date: April 27, 2007
Creator: Lawrence Berkeley National Laboratory. Advanced Light Source.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High Resolution/High Fidelity Seismic Imaging and Parameter Estimation for Geological Structure and Material Characterization

Description: Our proposed work on high resolution/high fidelity seismic imaging focused on three general areas: (1) development of new, more efficient, wave-equation-based propagators and imaging conditions, (2) developments towards amplitude-preserving imaging in the local angle domain, in particular, imaging methods that allow us to estimate the reflection as a function of angle at a layer boundary, and (3) studies of wave inversion for local parameter estimation. In this report we summarize the results a… more
Date: June 8, 2008
Creator: Wu, Ru-Shan & Xie, Xiao-Bi
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Measurement of Gas and Liquid Velocities in an Air-Water Two-Phase Flow using Cross-Correlation of Signals from a Double Senor Hot-Film Probe

Description: Local gas and liquid velocities are measured by cross-correlating signals from a double sensor hot-film anemometer probe in pure water flow and air water two-phase flow. The gas phase velocity measured in two-phase flow agrees with velocity data obtained using high-speed video to within +/-5%. A turbulent structure, present in the liquid phase, allows a correlation to be taken, which is consistent with the expected velocity profiles in pure liquid flow. This turbulent structure is also present … more
Date: February 19, 2002
Creator: Gurau, B.; Vassalo, P. & Keller, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Two-station phase velocity determination for structure in North Africa

Description: The seismic structure of North Africa is poorly understood due to the relative paucity of stations and seismicity when compared to other continental regions of the world. A better understanding of the velocity structure in this area will allow improved models of travel times and regional phase amplitudes. Such models will improve location and identification capability in this region leading to more effective monitoring of the Comprehensive Nuclear-Test-Ban Treaty. Using regional-to-teleseismic … more
Date: July 28, 1999
Creator: Hazler, S; Pasyanos, M; Sheehan, A & Walter, W
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Charge-State-Resolved Ion Energy Distribution Functions ofCathodic Vacuum Arcs: A Study Involving the Plasma Potential and BiasedPlasmas

Description: There are divergent results in the literature on the(in)dependence of the ion velocity distribution functions on the ioncharge states. Apparently, most time-of-flight methods of measurementsindicate independence whereas most measurements with electrostaticanalyzers state the opposite. It is shown here that this grouping iscoincidental with investigations of pulsed and continuous arcs. Allresults can be consolidated by taking ion-neutral interaction intoaccount, especially charge exchange collis… more
Date: March 9, 2006
Creator: Anders, Andre & Oks, Efim
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The universal criterion for switching a magnetic vortex core in soft magnetic nanodots

Description: The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {ra… more
Date: October 1, 2008
Creator: Lee, K. S.; Kim, S. K.; Yu, Y. S.; Choi, Y. S.; Guslienko, K. Y.; Jung, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Time-Domain Pure-state Polarization Analysis of Surface Waves Traversing California

Description: A time-domain pure-state polarization analysis method is used to characterize surface waves traversing California parallel to the plate boundary. The method is applied to data recorded at four broadband stations in California from twenty-six large, shallow earthquakes which occurred since 1988, yielding polarization parameters such as the ellipticity, Euler angles, instantaneous periods, and wave incident azimuths. The earthquakes are located along the circum-Pacific margin and the ray paths cl… more
Date: November 4, 2003
Creator: Zhang, Jiajun; Walter, William R.; Lay, Thorne & Wu, Ru-Shan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Sdssj103913.70+533029.7: a super star cluster in the outskirts of a galaxy merger

Description: We describe the serendipitous discovery in the spectroscopic data of the Sloan Digital Sky Survey of a star-like object, SDSSJ103913.70+533029.7, at a heliocentric radial velocity of +1012 km s{sup -1}. Its proximity in position and velocity to the spiral galaxy NGC 3310 suggests an association with the galaxy. At this distance, SDSSJ103913.70+533029.7 has the luminosity of a super star cluster and a projected distance of 17 kpc from NGC 3310. Its spectroscopic and photometric properties imply … more
Date: November 1, 2005
Creator: Knapp, Gillian R.; Tremonti, Christy A.; Rockosi, Constance M.; Schlegel, David J.; Yanny, Brian; Beers, Timothy C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Calibration of seismic wave propagation in Kuwait

Description: The Kuwait Institute of Scientific Research (KISR), the USGS and LLNL are collaborating to calibrate seismic wave propagation in Kuwait and surrounding regions of the northwest Arabian Gulf using data from the Kuwait National Seismic Network (KNSN). Our goals are to develop local and regional propagation models for locating and characterizing seismic events in Kuwait and portions of the Zagros mountains close to Kuwait. The KNSN consists of 7 short-period stations and one broadband (STS-2) stat… more
Date: July 23, 1999
Creator: Al-Awadhi, J.; Endo, E.; Fryall, F.; Harris, D.; Mayeda, K.; Rodgers, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The effect of compressibility on two-dimensional tunnel-wall interference for a symmetrical airfoil

Description: Summary: The effective change in the velocity of flow past a wing section, caused by the presence of wind-tunnel walls, is known for potential flow. This theory is extended by investigation of the two-dimensional compressible flow past a thin Rankine Oval. It is shown that for a symmetrical section at zero angle of attack the velocity increment due to the tunnel walls in the incompressible case must be multiplied by the factor 1/1-M^2 to take account of compressibility effects. The Mach numb… more
Date: May 1943
Creator: Nitzberg, Gerald E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Statistical Properties of Blue Horizontal Branch Stars in the Spheroid: Detection of a Moving Group approximately 50 kpc from the Sun

Description: A new moving group comprising at least four Blue Horizontal Branch (BHB) stars is identified at (l; b) = (65{sup o}; 48{sup o}). The horizontal branch at g{sub 0} = 18.9 magnitude implies a distance of 50 kpc from the Sun. The heliocentric radial velocity is <V{sub r}> = -157 {+-} 4 km s{sup -1}, corresponding to V{sub gsr} = -10 km s{sup -1}; the dispersion in line-of-sight velocity is consistent with the instrumental errors for these stars. The mean metallicity of the moving group is [F… more
Date: February 1, 2010
Creator: Harrigan, Matthew J.; Newberg, Heidi Jo; Newberg, Lee A.; Yanny, Brian; Beers, Timothy C.; Lee, Young Sun et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Radial Velocity and Mass of the White Dwarf of EX Hydrae Measured with Chandra

Description: We present the first detection of orbital motion in the cataclysmic variable EX Hydrae based on X-ray data from the Chandra X-Ray Observatory. The large collecting area of the telescope and the high resolution of the HETG spectrometers allow for an unprecedented velocity accuracy of {approx}km s{sup -1} in the X-ray wavelength regime. We find an emission line velocity amplitude of 58.2{+-}3.7 km s{sup -1} and infer a white dwarf mass of 0.49{+-}0.13 M{sub {circle_dot}}, in good agreement with p… more
Date: March 1, 2004
Creator: Mauche, C W; Hoogerwerf, R & Brickhouse, N S
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Turbulence simulations of x-point physics on the L-H transitions

Description: We show that the resistive X-point mode is dominant mode in boundary plasmas in X-point divertor geometry. The poloidal fluctuation phase velocity from the resistive X-point turbulence shows experimentally measured structure across separatrix. The fluctuation phase velocity is larger than E x B velocity both in L and H mode phases, by at least a factor of two. We also demonstrate that there is a strong poloidal asymmetry of particle flux in the proximity of the separatrix. Turbulence suppressio… more
Date: September 28, 2000
Creator: Xu, X. Q.; Cohen, R. H.; Nevins, W. M.; Porter, G. D.; Rensink, M. E.; Rognlien, T. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
Back to Top of Screen