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in subjects: "Anisotropy"  
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Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters for polar media

Description: Sayers and Kachanov (1991) defined crack-influence parameters that are shown to be directly related to Thomsen (1986) weak-anisotropy seismic parameters for fractured reservoirs when the crack/fracture density is small enough. These results are then applied to the problem of seismic wave propagation in polar (i.e., non-isotropic) reservoirs having HTI seismic wave symmetry due to the presence of aligned vertical fractures and resulting in azimuthal seismic wave symmetry at the earth's surface. … more
Date: December 12, 2007
Creator: Berryman, James G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Irreversible volume growth in polymer-bonded powder systems: effects of crystalline anisotropy, particle size distribution, and binder strength

Description: Pressed-powdered crystallites of intrinsically anisotropic materials have been shown to undergo irreversible volume expansion when subjected to repeated cycles of heating and cooling. We develop a coarse-grained (micron-scale) interaction Hamiltonian for this system and perform molecular dynamics simulations, which quantitatively reproduce the experimentally observed irreversible growth. The functional form and values of the interaction parameters at the coarse-grained level are motivated by ou… more
Date: August 22, 2007
Creator: Maiti, A.; Gee, R. H.; Hoffman, D. & Fried, L. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Spectroscopic Studies of Structure, Dynamics and Reactivity in Ionic Liquids.

Description: Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other … more
Date: November 30, 2007
Creator: Wishart, J. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Tantalum Shear Modulus from Homogenization of Single Crystal Data

Description: Elastic constants for tantalum single crystals have been calculated by Orlikowski, et al. [1] for a broad range of temperatures and pressures. These moduli can be utilized directly in continuum crystal simulations or dislocation dynamics calculations where the individual grains of the polycrystalline material are explicitly represented. For simulations on a larger size scale, the volume of material represented by the quadrature points of the simulation codes includes many grains, and average mo… more
Date: September 14, 2007
Creator: Becker, R
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Influence of interface exchange coupling in perpendicular anisotropy [Pt/Co]50/TbFe bilayers

Description: We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt]{sub 50} thin films either in direct contact resulting in antiferromagnetic interfacial coupling or separated by a thick Pt layer. Magnetometry and x-ray magnetic circular dichroism spectroscopy determine the spatially averaged magnetic properties. Resonant magnetic x-ray small-angle scattering and magnetic soft X-ray transmission microscopy probed the domain configurations and correlations in the reversal proces… more
Date: October 10, 2007
Creator: Mangin, S.; Hauet, T.; Fischer, P.; Kim, D.H.; Kortright, J.B.; Chesnel, K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ESTIMATING THE STRENGTH OF SINGLE-ENDED DISLOCATION SOURCES IN MICROMETER-SIZED SINGLE CRYSTALS

Description: A recent study indicated that the behavior of single-ended dislocation sources contributes to the flow strength of micrometer-scale crystals. In this study 3D discrete dislocation dynamics simulations of micrometer-sized volumes are used to calculate the effects of anisotropy of dislocation line tension (increasing Poisson's ratio, {nu}) on the strength of single-ended dislocation sources and, to compare them with the strength of double-ended sources of equal length. This is done by directly mo… more
Date: May 3, 2007
Creator: Rao, S I; Dimiduk, D M; Tang, M; Parthasarathy, T A; Uchic, M D & Woodward, C
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Exact seismic velocities for VTI and HTI media and extendedThomsen Formulas for stronger anisotropies

Description: I explore a different type of approximation to the exactanisotropic wave velocities as a function of incidence angle invertically transversely isotropic (VTI) media. This method extends theThomsen weak anisotropy approach to stronger anisotropy withoutsignificantly affecting the simplicity of the formulas. One importantimprovement is that the peak of the quasi-SV-wave speed vsv(theta) islocated at the correct incidence angle theta= theta max, rather thanalways being at the position theta = 45o,… more
Date: May 14, 2007
Creator: Berryman, J.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei

Description: Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of the cosmic rays with the highest energies, which are correlated with the positions of relatively nearby active galactic nuclei (AGN) [1]. The correlation has maximum significance for cosmic rays with energy greater than {approx} 6 x 10{sup 19} eV and AGN at a distance less than {approx} 75 Mpc. We have confirmed the anisotropy at a confidence level of more than 99% through a test with par… more
Date: December 1, 2007
Creator: Collaboration, The Pierre auger
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Direct Observation of Field and Temperature Induced Domain Replication in Dipolar Coupled Perpendicular Anisotropy Films

Description: Dipolar interactions in a soft/Pd/hard [CoNi/Pd]{sub 30}/Pd/[Co/Pd]{sub 20} multilayer system, where a thick Pd layer between two ferromagnetic units prevents direct exchange coupling, are directly revealed by combining magnetometry and state-of-the-art layer resolving soft x-ray imaging techniques with sub-100-nm spatial resolution. The domains forming in the soft layer during external magnetic field reversal are found to match the domains previously trapped in the hard layer. The low Curie te… more
Date: July 1, 2007
Creator: Hauet, T.; Gunther, C.M.; Pfau, B.; Eisebitt, S.; Fischer, P.; Rick, R. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Aligned vertical fractures, HTI reservoir symmetry, and Thomsenseismic anisotropy parameters

Description: The Sayers and Kachanov (1991) crack-influence parametersare shown to be directly related to Thomsen (1986) weak-anisotropyseismic parameters for fractured reservoirs when the crack density issmall enough. These results are then applied to seismic wave propagationin reservoirs having HTI symmetry due to aligned vertical fractures. Theapproach suggests a method of inverting for fracture density from wavespeed data.
Date: June 27, 2007
Creator: Berryman, James G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

INERI-2006-003-F FY07 Annual Report

Description: Project Title: Comparison of Characterization Methods for Anisotropy and Microstructure of TRISO Particle Layers This INERI was created to support a comparative study between the newly developed two modulator generalized ellipsometry microscope (2-MGEM) at the Oak Ridge National Laboratory (ORNL) and the more traditional optical polarimeter (RAPAX) at the Commissariat l' nergie Atomique (CEA). These two systems are used to measure the anisotropy of the pyrocarbon layers in tri-isotropic (TRISO)… more
Date: October 1, 2007
Creator: Hunn, John D
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mass, quark-number, and sqrt sNN dependence of the second andfourth flow harmonics in ultra-relativistic nucleus-nucleuscollisions

Description: We present STAR measurements of the azimuthal anisotropyparameter v_2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi,and \Omega + bar Omega, along with v_4 for pions, kaons, protons, andLambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4and 200 GeV. The v_2(p_T) values for all hadron species at 62.4 GeV aresimilar to those observed in 130 and 200 GeV collisions. For observedkinematic ranges, v_2 values at 62.4, 130, and 200 GeV are as little as10 percent-15 perce… more
Date: January 6, 2007
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett,J.; Anderson, B. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Seismic waves in rocks with fluids and fractures

Description: Seismic wave propagation through the earth is often stronglyaffected by the presence of fractures. When these fractures are filledwith fluids (oil, gas, water, CO2, etc.), the type and state of the fluid(liquid or gas) can make a large difference in the response of theseismic waves. This paper summarizes recent work on methods ofdeconstructing the effects of fractures, and any fluids within thesefractures, on seismic wave propagation as observed in reflection seismicdata. One method explored he… more
Date: May 14, 2007
Creator: Berryman, J.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measuring 10-1000 GeV Cosmic Ray Electrons with GLAST/LAT

Description: We present here the capabilities of the GLAST Large Area Telescope to detect cosmic ray high-energy (HE) electrons in the energy range from 10 GeV to 1 TeV. We also discuss the science topics that can be investigated with HE electron data and quantify the results with LAT instrument simulations. The science topics include CR propagation, calibration of the IC gamma-ray model, testing hypotheses regarding the origin of HE energy cosmic-ray electrons, searching for any signature of Kaluza Klein D… more
Date: July 16, 2007
Creator: Moiseev, Alexander A.; Ormes, Jonathan F. & Moskalenko, Igor V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Fundamental Scientific Problems in Magnetic Recording

Description: Magnetic data storage technology is presently leading the high tech industry in advancing device integration--doubling the storage density every 12 months. To continue these advancements and to achieve terra bit per inch squared recording densities, new approaches to store and access data will be needed in about 3-5 years. In this project, collaboration between Oak Ridge National Laboratory (ORNL), Center for Materials for Information Technology (MINT) at University of Alabama (UA), Imago Scien… more
Date: June 27, 2007
Creator: Schulthess, T. C. & Miller, M. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Time-Resolved Hard X-Ray Spectrometer

Description: Wired array studies are being conducted at the SNL Z accelerator to maximize the x-ray generation for inertial confinement fusion targets and high energy density physics experiments. An integral component of these studies is the characterization of the time-resolved spectral content of the x-rays. Due to potential spatial anisotropy in the emitted radiation, it is also critical to diagnose the time-evolved spectral content in a space-resolved manner. To accomplish these two measurement goals, w… more
Date: March 1, 2007
Creator: Moya, Kenneth; McKenna, Ian; Keenan, Thomas & Cuneo, Michael
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Signature of Patchy Reionization in the Polarization Anisotropy of the CMB

Description: The inhomogeneous ionization state of the universe when the first sources of ionizing radiation appeared should lead to anisotropies in the polarization of the cosmic microwave background. We use cosmological simulations of the process by which the first sources ionized the intergalactic medium to study the induced polarization anisotropies. We find that the polarization anisotropies have rms of order {approx} 0.01 {mu}K, and local peak values of {approx} 0.1 {mu}K, smaller than those due to gr… more
Date: May 16, 2007
Creator: Dore, Olivier; Astrophys., /Canadian Inst. Theor.; Holder, Gil; U., /McGill; Alvarez, Marcelo; /KIPAC, Menlo Park et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Structure of the Lithosphere and Upper Mantle Across the Arabian Peninsula

Description: Analysis of modern broadband (BB) waveform data allows for the inference of seismic velocity structure of the crust and upper mantle using a variety of techniques. This presentation will report inferences of seismic structure of the Arabian Plate using BB data from various networks. Most data were recorded by the Saudi Arabian National Digital Seismic Network (SANDSN) which consists of 38 (26 BB, 11 SP) stations, mostly located on the Arabian Shield. Additional data were taken from the 1995-7 S… more
Date: January 5, 2007
Creator: Al-Amri, A. & Rodgers, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy Lossand Flow of Heavy Quarks in Au+Au Collisions at root-s=200GeV

Description: The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < p{sub rmT} < 9 GeV/c at midrapidity (|y| < 0.35) from heavy flavor (charm and bottom) decays in Au+Au collisions at {radical}s{sub NN} = 200 GeV. The nuclear modification factor R{sub AA} relative to p+p collisions shows a strong suppression in central Au+Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC energies. A large azimuthal anisotr… more
Date: February 26, 2007
Creator: Soltz, R.; Klay, J.; Enokizono, A.; Newby, J.; Heffner, M. & Hartouni, E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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