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Low-frequency asymptotic analysis of seismic reflection from afluid-saturated medium

Description: Reflection of a seismic wave from a plane interface betweentwo elastic media does not depend on the frequency. If one of the mediais poroelastic and fluid-saturated, then the reflection becomesfrequency-dependent. This paper presents a low-frequency asymptoticformula for the reflection of seismic plane p-wave from a fluid-saturatedporous medium. The obtained asymptotic scaling of the frequency-dependentcomponent of the reflection coefficient shows that it is asymptoticallyproportional to the sq… more
Date: April 14, 2004
Creator: Silin, D.B.; Korneev, V.A.; Goloshubin, G.M. & Patzek, T.W.
Partner: UNT Libraries Government Documents Department
open access

Quadratic function approaching method for magnetotelluric soundingdata inversion

Description: The quadratic function approaching method (QFAM) is introduced for magnetotelluric sounding (MT) data inversion. The method takes the advantage of that quadratic function has single extreme value, which avoids leading to an inversion solution for local minimum and ensures the solution for global minimization of an objective function. The method does not need calculation of sensitivity matrix and not require a strict initial earth model. Examples for synthetic data and field measurement data ind… more
Date: April 5, 2004
Creator: Liangjun, Yan; Wenbao, Hu & Zhang, Keni
Partner: UNT Libraries Government Documents Department
open access

Feasibility of using biological degradation for the on-sitet reatment of mixed wastes

Description: This research was conducted to investigate the feasibility of applying microbial biodegradation as a treatment technology for wastes containing radioactive elements and organic solvents (mixed wastes). In this study, we focused our efforts on the treatment of wastes generated by biomedical research as the result of purifying tritium labeled compounds by high-performance liquid chromatography (HPLC). These wastes are typically 80 percent water with 20 percent acetonitrile or methanol or a mixtur… more
Date: April 20, 2004
Creator: Stringfellow, William T.; Komada, Tatsuyuki & Chang, Li-Yang
Partner: UNT Libraries Government Documents Department
open access

X-Ray Line Measurements with High Efficiency Bragg Crystals

Description: We have studied the focusing properties of two highly oriented pyrolitic graphite (HOPG) spectrometers, which differ in the degree of the mosaic spread: ZYA with a low mosaic spread ({gamma}=0.4 degrees) and ZYH with a large mosaic spread ({gamma}=3.5 degrees). In order to assess the crystal performance for a variety of different experiments, various K{alpha} and K{beta} x-ray lines have been produced using a high-intensity ({approx}>10{sup 17} W/cm{sup 2}) short-pulse ({approx} 100 fs) lase… more
Date: April 1, 2004
Creator: Pak, A; Gregori, G; Knight, J; Campbell, K; Landen, O & Glenzer, S
Partner: UNT Libraries Government Documents Department
open access

Large Eddy Simulation of Turbulent Flow and Dispersion in Urban Areas and Forest Canopies

Description: Under the sponsorship of the U.S. DOE and DHS, we have developed a CFD model for simulating flow and dispersion of chemical and biological agents released in the urban environment. Our model, FEM3MP (Chan and Stevens, 2000), is based on solving the three-dimensional, time-dependent, incompressible Navier-Stokes equations on massively parallel computer platforms. The model uses the finite element method for accurate representation of complex building shapes and variable terrain, together with a … more
Date: April 9, 2004
Creator: Chan, Stevens T.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the polarization of the K-shell resonance line emission of S13+ and S14+ at relativistic electron beam energies.

Description: We have measured the polarization of the heliumlike sulfur resonance line 1s2p {sup 1}P{sub 1} {yields} 1s{sup 2} {sup 1}S{sub 0}, and of the blend of the lithiumlike sulfur resonance lines 1s2s2p {sup 2}P{sub 3/2} {yields} 1s{sup 2}2s {sup 2}S{sub 1/2} and 1s2s2p {sup 2}P{sub 1/2} {yields} 1s{sup 2}2s {sup 2}S{sub 1/2} as a function of electron beam energy from near threshold to 144 keV. These lines were excited with the LLNL high-energy electron beam ion trap and measured using a newly modifi… more
Date: April 6, 2004
Creator: Robbins, D; Faenov, A Y; Pikuz, T; Chen, H; Beiersdorfer, P; May, M et al.
Partner: UNT Libraries Government Documents Department
open access

The Astro-E2 XRS/EBIT Microcalorimeter XC-ray Spectrometer

Description: The X-ray Spectrometer (XRS) instrument is a revolutionary non-dispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flight spare XRS microcalorimeter spectrometer at the EBIT-I and SuperEBIT facility at LLNL replacing the XRS from the earlier Astro-E mission and providing twice the resolving power. The XRS microcalorimeter is an x-ray detector that senses the heat deposited by the incident photon. It achieves a high e… more
Date: April 16, 2004
Creator: Porter, F S; Brown, G V; Boyce, K R; Kelley, R L; Kilbourne, C A; Beiersdorfer, P et al.
Partner: UNT Libraries Government Documents Department
open access

Implementation of Frictional Contact Conditions in Surface to Surface, Mortar Based Computational Frameworks

Description: A number of recent works have established the mortar technique as an accurate and robust spatial discretization method for contact problems in computational solid mechanics. Since methods based on this idea rely on an integral, non-local representation of the contact operators, their formulation is somewhat more involved than is true for more traditional ''point to surface'' contact algorithms; in particular, the integral projections have nontrivial linearizations in the fully large deformation… more
Date: April 1, 2004
Creator: Laursen, T. A.; Yang, B. & Puso, M. A.
Partner: UNT Libraries Government Documents Department
open access

A 3D Frictional Segment-to-Segment Contact Method for Large Deformations and Quadratic Elements

Description: Node-on-segment contact is the most common form of contact used today but has many deficiencies ranging from potential locking to non-smooth behavior with large sliding. Furthermore, node-on-segment approaches are not at all applicable to higher order discretizations (e.g. quadratic elements). In a previous work, [3, 4] we developed a segment-to-segment contact approach for eight node hexahedral elements based on the mortar method that was applicable to large deformation mechanics. The approach… more
Date: April 1, 2004
Creator: Puso, M; Laursen, T & Solberg, J
Partner: UNT Libraries Government Documents Department
open access

Studies of laser-driven radiative blast waves

Description: We have performed two sets of experiments looking at laser-driven radiating blast waves. In one set of experiments the effect of a drive laser's passage through a background gas on the hydrodynamical evolution of blast waves was examined. It was found that the laser's passage heats a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved … more
Date: April 29, 2004
Creator: Edwards, M J; Hansen, J; Edens, A; Ditmire, T; Adams, R; Rambo, P et al.
Partner: UNT Libraries Government Documents Department
open access

Heavy Meson Production at a Low-Energy Photon Collider

Description: A low-energy {gamma}{gamma} collider has been discussed in the context of a testbed for a {gamma}{gamma} interaction region at the Next Linear Collider(NLC). We consider the production of heavy mesons at such a testbed using Compton-backscattered photons and demonstrate that their production rivals or exceeds those by BELLE, BABAR or LEP where they are produced indirectly via virtual {gamma}{gamma} luminosities.
Date: April 15, 2004
Creator: Asztalos, S
Partner: UNT Libraries Government Documents Department
open access

The DNA sequence and biology of human chromosome 19

Description: Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high GC content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes a… more
Date: April 6, 2004
Creator: Grimwood, J.; Gordon, L. A.; Olsen, A.; Terry, A.; Schmutz, J.; Lamerdin, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Shielding a Streak Camera from Hard X-rays

Description: The targets used in the Hot Halfraum Campaign at OMEGA create many hot electrons, which result in a large flux of hard x-rays. The hard x-rays produce a high background in the streak camera. The background was significantly reduced by wrapping the streak camera with a high-Z material; in this case, 1/8' of Pb. The large hard x-ray flux also adds noise to images from framing cameras which use CCDs.
Date: April 14, 2004
Creator: Schneider, M.; Sorce, C.; Loughman, K.; Emig, J.; Bruns, H.; Back, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Resolving the Nature of the LMC Microlensing Event LMC-5

Description: The authors present the results from an analysis of Hubble Space Telescope High Resolution Camera data for the Large Magellanic Cloud microlensing event MACHO-LMC-5. By determining the parallax and proper motion of this object they find that the lens is an M dwarf star at a distance of 578{sub -53}{sup +65}pc with a proper motion of 21.39 {+-} 0.04 mas/yr. Based on the kinematics and location of this star is it more likely to be part of the Galactic thick disk than thin disk population. They co… more
Date: April 22, 2004
Creator: Drake, A J; Cook, K H & Keller, S C
Partner: UNT Libraries Government Documents Department
open access

Edward Teller's Scientific Life

Description: Edward Teller was one of the great physicists of the twentieth century. His career began just after the key ideas of the quantum revolution of the 1920's were completed, opening vast areas of physics and chemistry to detailed understanding. Thus, his early work in theoretical physics focused on applying the new quantum theory to the understanding of diverse phenomena. These topics included chemical physics, diamagnetism, and nuclear physics. Later, he made key contributions to statistical mecha… more
Date: April 15, 2004
Creator: Libby, S B & Weiss, M S
Partner: UNT Libraries Government Documents Department
open access

A Filter-Fluorescer Diagnostic System (FFLEX) for the National Ignition Facility (NIF)

Description: An early Filter-Fluorescer Diagnostic System (FFLEX) is being fielded at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) to measure the amount of hard x-rays (20 < hv < 150 keV) generated in laser fusion experiments. From these measurements we hope to quantify the number of hot (20 to 50 keV) electrons produced in laser fusion experiments. The Measurement of hot electron production is important for ignition experiments because these electrons can preh… more
Date: April 13, 2004
Creator: McDonald, J. W.; Kauffman, R. L.; Celeste, J. R.; Rhodes, M. A.; Lee, F. D.; Suter, L. J. et al.
Partner: UNT Libraries Government Documents Department
open access

A screening model for evaluating the degradation and transport of MTBE and other fuel oxygenates in the subsurface

Description: Methyl tert-butyl ether (MTBE) has received high attention as it contributed to cleaner air and contaminated thousands of underground storage tank sites. Because MTBE is very water soluble, it is more difficult to remove from water by conventional remediation techniques. Therefore, biodegradation of MTBE has become a remediation alternative. In order to understand the transport and transformation processes, they present a closed form solution as a screening tool in this paper. The possible reac… more
Date: April 20, 2004
Creator: Sun, Y. & Lu, X.
Partner: UNT Libraries Government Documents Department
open access

Development of LLNL Methodology for Nonnuclear Safety Bases

Description: The objective of this paper is to introduce the process and philosophies used to develop LLNL methodology for performing nonnuclear safety bases. Our former approach needed revision in order to implement the new Work Smart Standard (WSS), 'Safety Basis Requirements for Nonnuclear Facilities at Lawrence Livermore National Laboratory Site Specific Standard' (UCRL-ID-150214), approved in 2003 and revised January, 2004. This work relates directly to the following workshop theme: 'Improvements in Ch… more
Date: April 26, 2004
Creator: van Warmerdam, C M & Pinkston, D M
Partner: UNT Libraries Government Documents Department
open access

Optical Properties of Passivated Silicon Nanoclusters: The Role of Synthesis

Description: The effect of preparation conditions on the structural and optical properties of silicon nanoparticles is investigated. Nanoscale reconstructions, unique to curved nanosurfaces, are presented for silicon nanocrystals and shown to have lower energy and larger optical gaps than bulk-derived structures. We find that high-temperature synthesis processes can produce metastable non-crystalline nanostructures with different core structures than bulk-derived crystalline clusters. The type of core struc… more
Date: April 7, 2004
Creator: Draeger, E; Grossman, J; Williamson, A & Galli, G
Partner: UNT Libraries Government Documents Department
open access

Accessing High Pressure States Relevant to Core Conditions in the Giant Planets

Description: We have designed an experimental technique to use on the National Ignition Facility (NIF) laser to achieve very high pressure (P{sub max} > 10 Mbar = 1000 GPa), dense states of matter at moderate temperatures (kT < 0.5 eV = 6000 K), relevant to the core conditions of the giant planets. A discussion of the conditions in the interiors of the giant planets is given, and an experimental design that can approach those conditions is described.
Date: April 15, 2004
Creator: Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Ho, D. D.; Lorenz, K. T.; Lorenzana, H. E. et al.
Partner: UNT Libraries Government Documents Department
open access

Fracture Permeability Evolution in Rock from the Desert Peak EGS Site

Description: Fluid flow experiments are being conducted on core specimens of quartz monzonite retrieved from depths of about 1 km at the Desert Peak East EGS site in Churchill County, Nevada. Our immediate goal is to observe permeability evolution in fractures at pressure and temperature conditions appropriate to the Desert Peak geothermal site. Longer term, we aim to evaluate mechanisms that control the evolution of fracture permeability. In the experiments saline water is flowed through an artificial frac… more
Date: April 8, 2004
Creator: Carlson, S. R.; Roberts, J. J.; Detwiler, R. L.; Burton, E. A.; Robertson-Tait, A.; Morris, C. et al.
Partner: UNT Libraries Government Documents Department
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