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The AWM-SIAM Sonia Kovalesvky Lecture - 3 part Lecture Series

Description: The Association for Women in Mathematics (AWM) in cooperation with the Society for Industrial and Applied Mathematics (SIAM) and with funding from the Department of Energy initiated a new lecture series. The purpose of the lecture series is to increase the visibility of women who have made significant contributions in applied or computational mathematics. The AWM-SIAM Sonia Kovalevsky Lecture is presented at the SIAM Annual Meeting which is a national conference. The lecturer is a woman who has… more
Date: June 3, 2003
Creator: Lenhart, Suzanne & Lewis, Jennifer
Partner: UNT Libraries Government Documents Department
open access

Analyzing flow patterns in unsaturated fractured rock of YuccaMountain using an integrated modeling approach

Description: This paper presents a series of modeling investigations to characterize percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The investigations are conducted using a modeling approach that integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model through model calibration. This integrated modeling approach… more
Date: November 3, 2003
Creator: Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua & Bodvarsson,Gudmundur S.
Partner: UNT Libraries Government Documents Department
open access

Interfacial behavior of polymer electrolytes

Description: Evidence is presented concerning the effect of surfaces on the segmental motion of PEO-based polymer electrolytes in lithium batteries. For dry systems with no moisture the effect of surfaces of nano-particle fillers is to inhibit the segmental motion and to reduce the lithium ion transport. These effects also occur at the surfaces in composite electrodes that contain considerable quantities of carbon black nano-particles for electronic connection. The problem of reduced polymer mobility is com… more
Date: June 3, 2003
Creator: Kerr, John; Kerr, John B.; Han, Yong Bong; Liu, Gao; Reeder, Craig; Xie, Jiangbing et al.
Partner: UNT Libraries Government Documents Department
open access

Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests

Description: For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interp… more
Date: March 3, 2003
Creator: Cheng, J.; Twilley, K.; Murvosh, H.; Tu, Y.; Luke, B.; Yfantis, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Sheath Physics and Boundary Conditions for Edge Plasmas

Description: The boundary conditions of mass, momentum, energy, and charge appropriate for fluid formulations of edge plasmas are surveyed. We re-visit the classic problem of 1-dimensional flow, and note that the ''Bohm sheath criterion'' is requirement of connectivity of the interior plasma with the external world, not the result of termination of the plasma by a wall. We show that the nature of the interior plasma solution is intrinsically different for ion sources that inject above and below the electron… more
Date: September 3, 2003
Creator: Cohen, R. H. & Ryutov, D. D.
Partner: UNT Libraries Government Documents Department
open access

LORENTZ PHASE IMAGING AND IN-SITU LORENTZ MICROSCOPY OF PATTERNED CO-ARRAYS.

Description: Understanding magnetic structures and properties of patterned and ordinary magnetic films at nanometer length-scale is the area of immense technological and fundamental scientific importance. The key feature to such success is the ability to achieve visual quantitative information on domain configurations with a maximum ''magnetic'' resolution. Several methods have been developed to meet these demands (Kerr and Faraday effects, differential phase contrast microscopy, magnetic force microscopy, … more
Date: August 3, 2003
Creator: VOLKOV,V. V. ZHU,Y.
Partner: UNT Libraries Government Documents Department
open access

Many amino acid substitution variants identified in DNA repair genes during human population screenings are predicted to impact protein function

Description: Over 520 different amino acid substitution variants have been previously identified in the systematic screening of 91 human DNA repair genes for sequence variation. Two algorithms were employed to predict the impact of these amino acid substitutions on protein activity. Sorting Intolerant From Tolerant (SIFT) classified 226 of 508 variants (44%) as ''Intolerant''. Polymorphism Phenotyping (PolyPhen) classed 165 of 489 amino acid substitutions (34%) as ''Probably or Possibly Damaging''. Another … more
Date: November 3, 2003
Creator: Xi, T; Jones, I M & Mohrenweiser, H W
Partner: UNT Libraries Government Documents Department
open access

Coherent Communications, Imaging and Targeting

Description: Laboratory and field demonstration results obtained as part of the DARPA-sponsored Coherent Communications, Imaging and Targeting (CCIT) program are reviewed. The CCIT concept uses a Phase Conjugation Engine based on a quadrature receiver array, a hologram processor and a spatial light modulator (SLM) for high-speed, digital beam control. Progress on the enabling MEMS SLM, being developed by a consortium consisting of LLNL, academic institutions and small businesses, is presented.
Date: October 3, 2003
Creator: Stappaerts, E.; Baker, K.; Gavel, D.; Wilks, S.; Olivier, S.; Brase, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Self-Consistent Simulation of Turbulence and Transport in Tokamak Edge Plasmas

Description: The status of coupling the fluid 3D turbulence code BOUT and the fluid plasma/neutral 2D transport code UEDGE is reported, where both codes simulate the edge region of diverted tokamaks from several cm inside the magnetic separatrix to the far scrape-off layer (SOL), thereby including the magnetic X-point. Because the characteristic time scale of the turbulence is short ({approx} 10{sup -5}-10{sup -4}s) and the profile evolution time scale can be long ({approx} 10{sup -2}-10{sup -1} s owing to … more
Date: September 3, 2003
Creator: Rognlien, T D; Umansky, M V; Xu, X Q & Cohen, R H
Partner: UNT Libraries Government Documents Department
open access

Out-of-Core Compression and Decompression of Large n-Dimensional Scalar Fields

Description: We present a simple method for compressing very large and regularly sampled scalar fields. Our method is particularly attractive when the entire data set does not fit in memory and when the sampling rate is high relative to the feature size of the scalar field in all dimensions. Although we report results for R{sup 3} and R{sup 4} data sets, the proposed approach may be applied to higher dimensions. The method is based on the new Lorenzo predictor, introduced here, which estimates the value of … more
Date: February 3, 2003
Creator: Ibarria, L.; Lindstrom, P.; Rossignac, J. & Szymczak, A.
Partner: UNT Libraries Government Documents Department
open access

IMPROVEMENTS IN CODED APERTURE THERMAL NEUTRON IMAGING.

Description: A new thermal neutron imaging system has been constructed, based on a 20-cm x 17-cm He-3 position-sensitive detector with spatial resolution better than 1 mm. New compact custom-designed position-decoding electronics are employed, as well as high-precision cadmium masks with Modified Uniformly Redundant Array patterns. Fast Fourier Transform algorithms are incorporated into the deconvolution software to provide rapid conversion of shadowgrams into real images. The system demonstrates the princi… more
Date: August 3, 2003
Creator: VANIER,P. E.
Partner: UNT Libraries Government Documents Department
open access

Equal Optical Path Beam Splitters by Use of Amplitude-Splitting and Wavefront-Splitting Methods for Pencil Beam Interferometer.

Description: A beam splitter to create two separated parallel beams is a critical unit of a pencil beam interferometer, for example the long trace profiler (LTP). The operating principle of the beam splitter can be based upon either amplitude-splitting (AS) or wavefront-splitting (WS). For precision measurements with the LTP, an equal optical path system with two parallel beams is desired. Frequency drift of the light source in a non-equal optical path system will cause the interference fringes to drift. An… more
Date: August 3, 2003
Creator: Qian, S. & Takacs, P.
Partner: UNT Libraries Government Documents Department
open access

Chemical investigations of Element 108, Hassium (Hs)

Description: The basic aim of chemistry experiments of transactinide elements (TAN) is to establish their place in the periodic table of the elements, i.e. to determine if their chemical behavior is similar to the one of supposed homologs. In this contribution I will try to give an overview of all chemical experiments on element 108, hassium (Hs) that have been reported to date. Based on the systematics of the periodic table, Hs is expected to be a member of group 8 and therefore homologous to osmium (Os) a… more
Date: July 3, 2003
Creator: Dullmann, Christoph E.
Partner: UNT Libraries Government Documents Department
open access

Modified Rate-Theory Predictions in Comparison to Microstructural Data

Description: Standard rate theory methods have recently been combined with experimental microstructures to successfully reproduce measured swelling behavior in ternary steels around 400 C. Fit parameters have reasonable values except possibly for the recombination radius, R{sub c}, which can be larger than expected. Numerical simulations of void nucleation and growth reveal the importance additional recombination processes at unstable clusters. Such extra recombination may reduce the range of possible value… more
Date: November 3, 2003
Creator: Surh, M. P.; Okita, T. & Wolfer, W. G.
Partner: UNT Libraries Government Documents Department
open access

Recoil ion charge state distribution following the beta(sup +) decay of {sup 21}Na

Description: The charge state distribution following the positron decay of 21Na has been measured, with a larger than expected fraction of the daughter 21Ne in positive charge states. No dependence on either the positron or recoil nucleus energy is observed. The data is compared to a simple model based on the sudden approximation. Calculations suggest a small but important contribution from recoil ionization has important consequences for precision beta decay correlation experiments detecting recoil ions.
Date: January 3, 2003
Creator: Scielzo, Nicholas D.; Freedman, Stuart J.; Fujikawa, Brian K. & Vetter, Paul A.
Partner: UNT Libraries Government Documents Department
open access

Testing the cosmological constant as a candidate for dark energy

Description: It may be difficult to single out the best model of dark energy on the basis of the existing and planned cosmological observations, because many different models can lead to similar observational consequences. However, each particular model can be studied and either found consistent with observations or ruled out. In this paper, we concentrate on the possibility to test and rule out the simplest and by far the most popular of the models of dark energy, the theory described by general relativity… more
Date: December 3, 2003
Creator: Kratochvil, Jan; Linde, Andrei; Linder, Eric V. & Shmakova, Marina
Partner: UNT Libraries Government Documents Department
open access

SCOR: Structural classification of RNA, Version 2.0

Description: SCOR (http://scor.lbl.gov), the Structural Classification of RNA, is a database designed to provide a comprehensive perspective and understanding of RNA motif three-dimensional structure, function, tertiary interactions, and their relationships. SCOR 2.0 represents a major expansion and introduces a wholly new classification system. The new version represents the classification as a Directed Acyclic Graph (DAG), which allows a classification node to have multiple parents, in contrast to the str… more
Date: October 3, 2003
Creator: Tamura, Makio; Hendrix, Donna K. & Klosterman, Peter
Partner: UNT Libraries Government Documents Department
open access

X-ray study of aligned magnetic stripe domains in perpendicular multilayers

Description: We have investigated the stripe domain structure and the magnetic reversal of perpendicular Co/Pt based multilayers at room temperature using magnetometry, magnetic imaging and magnetic x-ray scattering. In-plane field cycling aligns the stripe domains along the field direction. In magnetic x-ray scattering the parallel stripe domains act as a magnetic grating resulting in observed Bragg reflections up to 5th order. We model the scattering profile to extract and quantify the domain as well as d… more
Date: March 3, 2003
Creator: Hellwig, O.; Denbeaux, G. P.; Kortright, J. B. & Fullerton, Eric E.
Partner: UNT Libraries Government Documents Department
open access

The impact of nanoscience on heterogeneous catalysis

Description: Most catalysts consist of nanometer-sized particles dispersed on a high-surface area support. Advances in characterization methods have led to a molecular level understanding of the relationships between nanoparticle properties and catalytic performance. Together with novel approaches to nanoparticle synthesis, this knowledge is contributing to the design and development of new catalysts.
Date: March 3, 2003
Creator: Bell, Alexis T.
Partner: UNT Libraries Government Documents Department
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