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Improved Operation of the SSPX Spheromak (open access)

Improved Operation of the SSPX Spheromak

None
Date: August 18, 2005
Creator: Wood, R. D.; Hill, D. N.; Hooper, E. B.; Woodruff, S.; McLean, H. S. & Stallard, B. W.
System: The UNT Digital Library
The Pathogenomic Sequence Analysis of B. cereus and B. thuringiensis Isolates Closely Related to Bacillus anthracis (open access)

The Pathogenomic Sequence Analysis of B. cereus and B. thuringiensis Isolates Closely Related to Bacillus anthracis

The sequencing and analysis of two close relatives of Bacillus anthracis are reported. AFLP analysis of over 300 isolates of B.cereus, B. thuringiensis and B. anthracis identified two isolates as being very closely related to B. anthracis. One, a B. cereus, BcE33L, was isolated from a zebra carcass in Nambia; the second, a B. thuringiensis, 97-27, was isolated from a necrotic human wound. The B. cereus appears to be the closest anthracis relative sequenced to date. A core genome of over 3,900 genes was compiled for the Bacillus cereus group, including Banthracis. Comparative analysis of these two genomes with other members of the B. cereus group provides insight into the evolutionary relationships among these organisms. Evidence is presented that differential regulation modulates virulence, rather than simple acquisition of virulence factors. These genome sequences provide insight into the molecular mechanisms contributing to the host range and virulence of this group of organisms.
Date: August 18, 2005
Creator: Han, Cliff S.; Xie, Gary; Challacombe, Jean F.; Altherr, MichaelR.; Smriti, B.; Bruce, David et al.
System: The UNT Digital Library
Using Decision Trees for Comparing Pattern Recognition Feature Sets (open access)

Using Decision Trees for Comparing Pattern Recognition Feature Sets

Determination of the best set of features has been acknowledged as one of the most difficult tasks in the pattern recognition process. In this report significance tests on the sort-ordered, sample-size normalized vote distribution of an ensemble of decision trees is introduced as a method of evaluating relative quality of feature sets. Alternative functional forms for feature sets are also examined. Associated standard deviations provide the means to evaluate the effect of the number of folds, the number of classifiers per fold, and the sample size on the resulting classifications. The method is applied to a problem for which a significant portion of the training set cannot be classified unambiguously.
Date: August 18, 2005
Creator: Proctor, D D
System: The UNT Digital Library
Laboratory astrophysics and atomic physics using the NASA/GSFC microcalorimeter spectrometers at the LLNL Electron Beam Ion Trap and Radiation Properties Facility (open access)

Laboratory astrophysics and atomic physics using the NASA/GSFC microcalorimeter spectrometers at the LLNL Electron Beam Ion Trap and Radiation Properties Facility

The 32 pixel laboratory microcalorimeter spectrometer built by the NASA/Goddard Space Flight Center is now an integral part of the spectroscopy suite used routinely by the electron beam ion trap and radiative properties group at the Lawrence Livermore National Laboratory. The second generation laboratory instrument, dubbed the XRS/EBIT, is nearly identical to the XRS instrument on the Suzaku X-ray Observatory, formerly Astro-E2. The detector array is from the same processed wafer and uses the same HgTe absorbers. it is being used to measure the photon emission from a variety of radiation sources. These include x-ray emission from laboratory simulated celestial sources, x-ray emission from highly charged ions of Au, and x-ray emission following charge exchange and radiative electron capture. The wide range of applications demonstrates the versatility of a high-resolution, high-efficiency low temperature detector that is able to collect data continually with minimal operator servicing.
Date: August 18, 2005
Creator: Brown, G.; Beiersdorfer, P.; Boyce, K.; Chen, H.; Gu, M. F.; Kahn, S. et al.
System: The UNT Digital Library
Magnetohydrodynamic Turbulence Simulations on the Earth SimulatorUsing the Lattice Boltzmann Method (open access)

Magnetohydrodynamic Turbulence Simulations on the Earth SimulatorUsing the Lattice Boltzmann Method

None
Date: August 18, 2005
Creator: Carter, Jonathan; Soe, Min; Oliker, Leonid; Tsuda, Yoshinori; Vahala, George; Vahala, Linda et al.
System: The UNT Digital Library
SAFETY STUDIES TO MEASURE EXOTHERMIC REACTIONS OF SPENT PLUTONIUM DECONTAMINATION CHEMICALS USING WET & DRY DECONTAMINATION METHODS (open access)

SAFETY STUDIES TO MEASURE EXOTHERMIC REACTIONS OF SPENT PLUTONIUM DECONTAMINATION CHEMICALS USING WET & DRY DECONTAMINATION METHODS

None
Date: August 18, 2005
Creator: HOPKINS, A.M.; JACKSON, G.W.; MINETTE, M.; EWALT, J.; COOPER, T.; SCOTT, P. et al.
System: The UNT Digital Library
MATERIAL QUALITY CHARACTERIZATION OF CDZNTE SUBSTRATES FOR HGCDTE EPITAXY. (open access)

MATERIAL QUALITY CHARACTERIZATION OF CDZNTE SUBSTRATES FOR HGCDTE EPITAXY.

CdZnTe (CZT) has been traditionally used as substrate for HgCdTe (MCT) epitaxy. The constraint of good lattice matching plays a fundamental role in the use of this substrate. In, fact, despite the difficulties in growing large area of affordable high-quality substrates, CZT wafers remain the best choice for high yield infrared devices. Nevertheless, material quality of the substrate and epilayer play a limiting role in IR focal plane array (FPA) detector technology. Furthermore, data suggest that the quality of the epilayer is affected by imperfections in the CZT substrate. In addition the pixel size for the current generation of FPAs (less than 20 {micro}m) suggests a need for detailed microscale characterization and an understanding of the substrates and epilayers on at least the spatial scale of the pixel dimensions. In an effort to understand the correlation between material quality and device performances, we have begun to study CZT substrates to investigate bulk and surface properties. The National Synchrotron Light Source (NSLS, BNL) permits a wide variety of material investigations that take advantage of the highly collimated photon radiation emitted from the X-ray and VUV-IR rings. Synchrotron radiation offers the capability to combine good resolution and shorter exposure times than conventional …
Date: August 18, 2005
Creator: Carini, G. A.; Bolotnikov, A. E.; Camarda, G. S.; James, R. B. & AL., ET
System: The UNT Digital Library
The Piece Wise Linear Reactive Flow Model (open access)

The Piece Wise Linear Reactive Flow Model

For non-ideal explosives a wide range of behavior is observed in experiments dealing with differing sizes and geometries. A predictive detonation model must be able to reproduce many phenomena including such effects as: variations in the detonation velocity with the radial diameter of rate sticks; slowing of the detonation velocity around gentle corners; production of dead zones for abrupt corner turning; failure of small diameter rate sticks; and failure for rate sticks with sufficiently wide cracks. Most models have been developed to explain one effect at a time. Often, changes are made in the input parameters used to fit each succeeding case with the implication that this is sufficient for the model to be valid over differing regimes. We feel that it is important to develop a model that is able to fit experiments with one set of parameters. To address this we are creating a new generation of models that are able to produce better fitting to individual data sets than prior models and to simultaneous fit distinctly different regimes of experiments. Presented here are details of our new Piece Wise Linear reactive flow model applied to LX-17.
Date: August 18, 2005
Creator: Vitello, P & Souers, P C
System: The UNT Digital Library
Collider Phenomenology of Higgs Bosons in Left-RightSymmetric Randall-Sundrum Models (open access)

Collider Phenomenology of Higgs Bosons in Left-RightSymmetric Randall-Sundrum Models

We study the corrections to Higgs physics in a model of a single warped extra dimension with all fields except the Higgs in the bulk, and a gauge symmetry extended to SU(2){sub L} x SU(2){sub R} x U(1){sub B-L}. We find that generically the Higgs coupling to electroweak gauge boson pairs is suppressed, the coupling to gluons is enhanced, and the coupling to photons is often suppressed, but can be enhanced.
Date: August 18, 2005
Creator: Lillie, B.
System: The UNT Digital Library
Helium Pot System for Maintaining Sample Temperature after Cryocooler Deactivation (open access)

Helium Pot System for Maintaining Sample Temperature after Cryocooler Deactivation

None
Date: August 18, 2005
Creator: Haid, B J
System: The UNT Digital Library
Simulation of Positronium: Toward More Realistic Models of Void Spaces in Materials (open access)

Simulation of Positronium: Toward More Realistic Models of Void Spaces in Materials

An exact treatment of the positron and electron in a two-chain, Path Integral Monte Carlo (PIMC) simulation is used to calculate both self-annihilation and pickoff rates at finite temperature. It has already been demonstrated that this technique can reproduce and extend results of simple theories of positrons and positronium (Ps) in spherical voids. Here, we include the effect of the linear dielectric response of a homogeneous material on the annihilation rate of positrons and Ps. In addition, we find lifetimes and structural information for Ps in cylindrical channels, both with and without adsorbed fluid atoms.
Date: August 18, 2005
Creator: Bug, A; Cronin, T; Sterne, P & Wolfson, Z
System: The UNT Digital Library
Full Detector Simulation Using SLIC and LCDD (open access)

Full Detector Simulation Using SLIC and LCDD

Simulator for the Linear Collider (SLIC) and Linear Collider Detector Description (LCDD) provide a flexible and powerful package for full detector simulations. This paper outlines the main features of SLIC and LCDD and explains the structure of an LCDD document used for detector description input.
Date: August 18, 2005
Creator: McCormick, J.
System: The UNT Digital Library