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Optical analogs of model atoms in fields (open access)

Optical analogs of model atoms in fields

The equivalence of the paraxial wave equation to a time-dependent Schroedinger equation is exploited to construct optical analogs of model atoms in monochromatic fields. The approximation of geometrical optics provides the analog of the corresponding classical mechanics. Optical analogs of Rabi oscillations, photoionization, stabilization, and the Kramers-Henneberger transformation are discussed. One possibility for experimental realization of such optical analogs is proposed. These analogs may be useful for studies of quantum chaos'' when the ray trajectories are chaotic. 9 refs.
Date: May 2, 1991
Creator: Milonni, P.W.
System: The UNT Digital Library
LSI/CAMAC system for heavy elements research (open access)

LSI/CAMAC system for heavy elements research

We have developed a LSI-11/23 computer-driven CAMAC data acquisition system. The 64 silicon-detector system is being used to investigate the alpha and spontaneous fission activities of short-lived transfermium isotopes by the real-time monitoring of the mother-daughter alpha decay sequence. A unique modular pulse processing electronics system was designed to simplify set up and calibration. The computer adjusts the gain of the CAMAC shaping amplifiers enabling the calibration and alignment of all 64 of the 1 k alpha spectra to within 0.5 channel in less than 10 minutes.
Date: May 2, 1985
Creator: Watkins, E. D.; Dougan, R. J. & McQuaid, J. H.
System: The UNT Digital Library
Galvanic interpretation of self-potential signals associated withmicrobial sulfate-reduction (open access)

Galvanic interpretation of self-potential signals associated withmicrobial sulfate-reduction

We have evaluated the usefulness of the self-potential (SP)geophysical method to track the onset and location of microbialsulfate-reduction in saturated sediments during organic carbon amendment.Following stimulation of sulfate-reducing bacteria (SRB) by addition oflactate, anomalous voltages exceeding 600 mV correlated in space and timewith the accumulation of dissolved sulfide. Abiotic experiments in whichthe sulfide concentration at the measurement electrode was systematicallyvaried showed a positive correlation between the magnitude of the SPanomaly and differences in the half-cell potential associated with themeasurement and reference electrodes. Thus, we infer that the SPanomaliesresulted from electrochemical differences that developedbetween sulfide-rich regions and areas having higher oxidation potential.In neither experiment did generation of an SP anomaly require thepresence of an in situ electronic conductor, as is required by othermodels. These findings emphasize the importance of incorporation ofelectrochemical effects at electrode surfaces in interpretation of SPdata from geophysical studies. We conclude that SP measurements provide aminimally invasive means for monitoring stimulated sulfate-reductionwithin saturated sediments.
Date: May 2, 2007
Creator: Williams, Kenneth H.; Hubbard, Susan S. & Banfield, Jillian F.
System: The UNT Digital Library
Effect of rogue particles on the sub-surface damage of fused silica during grinding/polishing (open access)

Effect of rogue particles on the sub-surface damage of fused silica during grinding/polishing

The distribution and characteristics of surface cracks (i.e., sub-surface damage or scratching) on fused silica formed during grinding/polishing resulting from the addition of rogue particles in the base slurry has been investigated. Fused silica samples (10 cm diameter x 1 cm thick) were: (1) ground by loose abrasive grinding (alumina particles 9-30 {micro}m) on a glass lap with the addition of larger alumina particles at various concentrations with mean sizes ranging from 15-30 {micro}m, or (2) polished (using 0.5 {micro}m cerium oxide slurry) on various laps (polyurethanes pads or pitch) with the addition of larger rogue particles (diamond (4-45 {micro}m), pitch, dust, or dried Ceria slurry agglomerates) at various concentrations. For the resulting ground samples, the crack distributions of the as-prepared surfaces were determined using a polished taper technique. The crack depth was observed to: (1) increase at small concentrations (>10{sup -4} fraction) of rogue particles; and (2) increase with rogue particle concentration to crack depths consistent with that observed when grinding with particles the size of the rogue particles alone. For the polished samples, which were subsequently etched in HF:NH{sub 4}F to expose the surface damage, the resulting scratch properties (type, number density, width, and length) were characterized. The …
Date: May 2, 2007
Creator: Suratwala, T I; Steele, R; Feit, M D; Wong, L; Miller, P E; Menapace, J A et al.
System: The UNT Digital Library
Ovarian carcinomas with genetic and epigenetic BRCA1 loss have distinct molecular abnormalities (open access)

Ovarian carcinomas with genetic and epigenetic BRCA1 loss have distinct molecular abnormalities

Subclassification of ovarian carcinomas can be used to guide treatment and determine prognosis. Germline and somatic mutations, loss of heterozygosity (LOH), and epigenetic events such as promoter hypermethylation can lead to decreased expression of BRCA1/2 in ovarian cancers. The mechanism of BRCA1/2 loss is a potential method of subclassifying high grade serous carcinomas. A consecutive series of 49 ovarian cancers was assessed for mutations status of BRCA1 and BRCA2, LOH at the BRCA1 and BRCA2 loci, methylation of the BRCA1 promoter, BRCA1, BRCA2, PTEN, and PIK3CA transcript levels, PIK3CA gene copy number, and BRCA1, p21, p53, and WT-1 immunohistochemistry. Eighteen (37%) of the ovarian carcinomas had germline or somatic BRCA1 mutations, or epigenetic loss of BRCA1. All of these tumors were high-grade serous or undifferentiated type. None of the endometrioid (n=5), clear cell (n=4), or low grade serous (n=2) carcinomas showed loss of BRCA1, whereas 47% of the 38 high-grade serous or undifferentiated carcinomas had loss of BRCA1. It was possible to distinguish high grade serous carcinomas with BRCA1 mutations from those with epigenetic BRCA1 loss: tumors with BRCA1 mutations typically had decreased PTEN mRNA levels while those with epigenetic loss of BRCA1 had copy number gain of PIK3CA. Overexpression …
Date: May 2, 2008
Creator: Gilks, C. Blake; Press, Joshua Z.; De Luca, Alessandro; Boyd, Niki; Young, Sean; Troussard, Armelle et al.
System: The UNT Digital Library
Electron-Heated Target Temperature Measurements in Petawatt Laser Experiments Based on Extreme Ultraviolet Imaging and Spectroscopy (open access)

Electron-Heated Target Temperature Measurements in Petawatt Laser Experiments Based on Extreme Ultraviolet Imaging and Spectroscopy

Three independent methods (XUV spectroscopy, imaging at 68 eV and 256 eV) have been used to measure planar target rear surface plasma temperature due to heating by hot electrons. The hot electrons are produced by ultra-intense laser plasma interactions using the 150 J, 0.5 ps Titan laser. Soft x-ray spectroscopy in the 50-400 eV region and imaging at the 68 eV and 256 eV photon energies were used to determine the rear surface temperature of planar CD targets. Temperatures were found to be in the 60-150 eV range, with good agreement between the three diagnostics.
Date: May 2, 2008
Creator: Ma, T. A.; Beg, F. N.; Macphee, A. G.; Chung, H. K.; Key, M. H.; Mackinnon, A. J. et al.
System: The UNT Digital Library
A Bremsstrahlung Spectrometer using k-edge and Differential Filters with Image plate dosimeters (open access)

A Bremsstrahlung Spectrometer using k-edge and Differential Filters with Image plate dosimeters

A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with Image Plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code Integrated Tiger Series 3.0 and the dosimeters calibrated with radioactive sources. Electron distributions with slope temperatures in the MeV range are inferred from the Bremsstrahlung spectra.
Date: May 2, 2008
Creator: Chen, C.; Mackinnon, A.; Beg, F.; Chen, H.; Key, M.; King, J. A. et al.
System: The UNT Digital Library
High Bandwidth Data Recording Systems for Pulsed Power and Laser Produced Plasma Experiments. (open access)

High Bandwidth Data Recording Systems for Pulsed Power and Laser Produced Plasma Experiments.

We present two high bandwidth data transmission and recording systems for the measurement of transient signals during pulsed power and laser produced plasmas. These systems use fiber optic cables to transmit analog data over long distances to high bandwidth digitizing oscilloscopes. One system is based on the direct modulation of a laser diode and has a bandwidth of 1.5 GHz. The other system is based upon a fiber-optic Mach-Zehnder modulator and has a bandwidth of 12 GHz, and is limited by the photo receiver. The signals are recorded on commercial digitizing oscilloscopes that have approximately 6 effective bits. The transmission systems use many off-the-shelf components from the telecommunications industry and thus have a high reliability and a moderate cost. Results from recent measurements will be presented. Investigation of the reduction in optical transmission by the fibers during exposure to high dose radiation will also be discussed.
Date: May 2, 2006
Creator: May, M. J.; Clancy, T.; Fittinghoff, D.; Halvorson, C.; MIlls, T.; Nikitin, A. et al.
System: The UNT Digital Library
Influence of radiation damage and isochronal annealing on the magnetic susceptibility of Pu(1-x)Am(x) alloys (open access)

Influence of radiation damage and isochronal annealing on the magnetic susceptibility of Pu(1-x)Am(x) alloys

Results of radiation damage in Pu and Pu{sub 1-x}Am{sub x} alloys studied with magnetic susceptibility, {chi}(T), and resistivity are presented. Damage accumulated at low temperatures increases {chi}(T) for all measured alloys, with the trend generally enhanced as the lattice expands. There is a trend towards saturation observable in the damage induced magnetic susceptibility data, that is not evident in similar damage induced resistivity data taken on the same specimen. A comparison of isochronal annealing curves measured by both resistivity and magnetic susceptibility on a 4.3at% Ga stabilized {delta}-Pu specimen show that Stage I annealing, where interstitials begin to move, is largely transparent to the magnetic measurement. This indicates that interstitials have little impact on the damage induced increase in the magnetic susceptibility. The isochronal annealing curves of the Pu{sub 1-x}Am{sub x} alloys do not show distinct annealing stages as expected for alloys. However, samples near 20% Am concentration show an unexpected increase in magnetization beginning when specimens are annealed to 35K. This behavior is also reflected in a time dependent increase in the magnetic susceptibility of damaged specimens indicative of first order kinetics. These results suggest there may be a metastable phase induced by radiation damage and annealing in Pu{sub …
Date: May 2, 2008
Creator: McCall, S; Fluss, M; Chung, B & Haire, R
System: The UNT Digital Library
Fabry-Perot / PDV Comparison (open access)

Fabry-Perot / PDV Comparison

Measures the fast pulses seen with exploding bridge flyers by PDV
Date: May 2, 2007
Creator: Hodgin, Ralph; May, Chadd; Hanks, Roy; Hansen, Don; Whitworth, Tony & Strand, Ted
System: The UNT Digital Library
Overview of equilibrium reconstruction on DIII-D using new measurements from an expanded motional Stark effect diagnostic (open access)

Overview of equilibrium reconstruction on DIII-D using new measurements from an expanded motional Stark effect diagnostic

Motional Stark effect (MSE) measurements constrain equilibrium reconstruction of DIII-D tokamak plasmas using the equilibrium code EFIT. In 2007, two new MSE arrays were brought online, bringing the system to three core arrays, two edge arrays, and 64 total channels. We present the first EFIT reconstructions using this expanded system. Safety factor and E{sub R} profiles produced by fitting to data from the two new arrays and one of the other three agree well with independent measurements. Comparison of the data from the three arrays that view the core shows that one of the older arrays is inconsistent with the other two unless the measured calibration factors for this array are adjusted. The required adjustments depend on toroidal field and plasma current direction, and on still other uncertain factors that change as the plasma evolves. We discuss possible sources of calibration error for this array.
Date: May 2, 2008
Creator: Holcomb, C; Makowski, M; Allen, S; Meyer, W & Van Zeeland, M
System: The UNT Digital Library
How to Find More Supernovae with Less Work: Object ClassificationTechniques for Difference Imaging (open access)

How to Find More Supernovae with Less Work: Object ClassificationTechniques for Difference Imaging

We present the results of applying new object classificationtechniques to difference images in the context of the Nearby SupernovaFactory supernova search. Most current supernova searches subtractreference images from new images, identify objects in these differenceimages, and apply simple threshold cuts on parameters such as statisticalsignificance, shape, and motionto reject objects such as cosmic rays,asteroids, and subtraction artifacts. Although most static objectssubtract cleanly, even a very low false positive detection rate can leadto hundreds of non-supernova candidates which must be vetted by humaninspection before triggering additional followup. In comparison to simplethreshold cuts, more sophisticated methods such as Boosted DecisionTrees, Random Forests, and Support Vector Machines provide dramaticallybetter object discrimination. At the Nearby Supernova Factory, we reducedthe number of non-supernova candidates by a factor of 10 while increasingour supernova identification efficiency. Methods such as these will becrucial for maintaining a reasonable false positive rate in the automatedtransient alert pipelines of upcoming projects such as PanSTARRS andLSST.
Date: May 2, 2007
Creator: Bailey, Stephen; Aragon, Cecilia; Romano, Raquel; Thomas, RollinC.; Weaver, Benjamin A. & Wong, Daniel
System: The UNT Digital Library
Angular Distributions in the Decays B to K*l+l- (open access)

Angular Distributions in the Decays B to K*l+l-

The authors use a sample of 384 million B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider to study angular distributions in the rare decays B {yields} K*{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -}. For low dilepton invariant masses, m{sub {ell}{ell}} < 2.5 GeV/c{sup 2}, they measure a lepton forward-backward asymmetry {Alpha}{sub FB} = 0.24{sub -0.23}{sup +0.18} {+-} 0.05 and K* longitudinal polarization F{sub L} = 0.35 {+-} 0.16 {+-} 0.04. For m{sub {ell}{ell}} > 3.2 GeV/c{sup 2}, they measure {Alpha}{sub FB} = 0.76{sub -0.32}{sup +0.52} {+-} 0.07 and F{sub L} = 0.71{sub -0.22}{sup 0.20} {+-} 0.04.
Date: May 2, 2008
Creator: Collaboration, The BABAR & Aubert, B.
System: The UNT Digital Library
Towards consistent chronology in the early Solar System: high resolution 53Mn-53Cr chronometry for chondrules. (open access)

Towards consistent chronology in the early Solar System: high resolution 53Mn-53Cr chronometry for chondrules.

New high-precision {sup 53}Mn-{sup 53}Cr data obtained for chondrules extracted from a primitive ordinary chondrite, Chainpur (LL3.4), define an initial {sup 53}Mn/{sup 55}Mn ratio of (5.1 {+-} 1.6) x 10{sup -6}. As a result of this downward revision from an earlier higher value of (9.4 {+-} 1.7) x 10{sup -6} for the same meteorite (Nyquist et al. 2001), together with an assessment of recent literature, we show that a consistent chronology with other chronometers such as the {sup 26}Al-{sup 26}Mg and {sup 207}Pb-{sup 206}Pb systems emerges in the early Solar System.
Date: May 2, 2007
Creator: Yin, Q; Jacobsen, B; Moynier, F & Hutcheon, I D
System: The UNT Digital Library
A Hard X-ray View on Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113 (open access)

A Hard X-ray View on Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113

TeV-blazars are known as prominent non-thermal emitters across the entire electromagnetic spectrum with their photon power peaking in the X-ray and TeV-band. If distant, absorption of -ray photons by the extragalactic background light (EBL) alters the intrinsic TeV spectral shape, thereby affecting the overall interpretation. Suzaku observations for two of the more distant TeV-blazars known to date, 1ES 1101-232 and 1ES 1553+113, were carried out in May and July 2006, respectively, including a quasi-simultaneous coverage with the state of the art Cherenkov telescope facilities. We report on the resulting data sets with emphasis on the X-ray band, and set into context to their historical behavior. During our campaign, we did not detect any significant X-ray or {gamma}-ray variability. 1ES 1101-232 was found in a quiescent state with the lowest X-ray flux ever measured. The combined XIS and HXD PIN data for 1ES 1101-232 and 1ES 1553+113 clearly indicate spectral curvature up to the highest hard X-ray data point ({approx} 30 keV), manifesting as softening with increasing energy. We describe this spectral shape by either a broken power law or a log-parabolic fit with equal statistical goodness of fits. The combined 1ES 1553+113 very high energy spectrum (90-500 GeV) did not …
Date: May 2, 2008
Creator: Reimer, A.; Costamente, L.; /Stanford U., HEPL /KIPAC, Menlo Park; Madejski, G.; /KIPAC, Menlo Park /SLAC; Reimer, O. et al.
System: The UNT Digital Library
FOAM DENSITY SENSITIVITY STUDY FOR THE 9977 PACKAGE (open access)

FOAM DENSITY SENSITIVITY STUDY FOR THE 9977 PACKAGE

Two layers of insulation fill the volume of the 9977 package between the drum liner and the shell. One of these layers is composed of General Plastics FR-3716 polyurethane foam (also known as Last-A-Foam{reg_sign}), poured through fill holes in the drum bottom and foamed in place. There was concern that the density of the foam insulating layer may vary due to the manufacturing process and that variations in foam density would compromise the safety basis of the package. Thus, a structural finite element analysis was performed to investigate this concern. The investigation examined the effect of replacing the material properties for the FR-3716 polyurethane foam, which has a density equal to 16 lb{sub m}/ft{sup 3}, with material properties of similar foam with varying densities through finite element analysis of hypothetical accident conditions (HAC) pertaining to impact conditions. The results showed that the functional performance of the containment vessel (CV) was not compromised under the conditions investigated.
Date: May 2, 2008
Creator: Gorczyca, J & Tsu-Te Wu, T
System: The UNT Digital Library
Babel Fortran 2003 Binding for Structured Data Types (open access)

Babel Fortran 2003 Binding for Structured Data Types

Babel is a tool aimed at the high-performance computing community that addresses the need for mixing programming languages (Java, Python, C, C++, Fortran 90, FORTRAN 77) in order to leverage the specific benefits of those languages. Scientific codes often rely on structured data types (structs, derived data types) to encapsulate data, and Babel has been lacking in this type of support until recently. We present a new language binding that focuses on their interoperability of C/C++ with Fortran 2003. The new binding builds on the existing Fortran 90 infrastructure by using the iso-c-binding module defined in the Fortran 2003 standard as the basis for C/C++ interoperability. We present the technical approach for the new binding and discuss our initial experiences in applying the binding in FACETS (Framework Application for Core-Edge Transport Simulations) to integrate C++ with legacy Fortran codes.
Date: May 2, 2008
Creator: Muszala, S; Epperly, T & Wang, N
System: The UNT Digital Library
Dirty Bomb Fallout (open access)

Dirty Bomb Fallout

At present, there is a significant need to develop decontamination agents that can be used effectively after detonation of a radiological dispersal device (RDD) in an urban environment. There is also a need for the development of reproducible test surfaces to be used to determine the efficacy of the agent being developed. Researchers at Lawrence Livermore National Laboratory (LLNL), under the auspices of the US Department of Energy (DoE), conducted a field study to evaluate the deposition of an explosively dispersed radionuclide surrogate (CsCl) on grime-bearing and non-grime-bearing urban surfaces. The goal was to investigate the preparation and contamination of urban surfaces that closely mimic what one would expect to encounter following the detonation of an RDD. Migration of Cs into concrete surfaces was investigated in detail. Many non-proliferation, security and response organizations that have modeled RDD scenarios use cesium-137, as well as cobalt-60, strontium-90, americium-241 as the most likely RDD agents. Cesium-137 is an isotope of concern for possible use in an RDD due to its potential availability resulting from its widespread legitimate use in construction, geotechnical and medical industrial devices. In some Cs-containing instruments the Cesium-137 is present as the highly dispersible and water soluble salt, cesium chloride …
Date: May 2, 2007
Creator: Gates-Anderson, D.; Rasmussen, C.; Fischer, R.; Viani, B.; Hu, Q.; Sutton, M. et al.
System: The UNT Digital Library
X-ray Thomson Scattering from Dense Plasmas (open access)

X-ray Thomson Scattering from Dense Plasmas

None
Date: May 2, 2007
Creator: Glenzer, S H
System: The UNT Digital Library
Dark Matter Capture and Annihilation on the First Stars: Preliminary Estimates (open access)

Dark Matter Capture and Annihilation on the First Stars: Preliminary Estimates

Assuming that Dark Matter is dominated by WIMPs, it accretes by gravitational attraction and scattering over baryonic material and annihilates inside celestial objects, giving rise to a 'Dark Luminosity' which may potentially affect the evolution of stars. We estimate the Dark Luminosity achieved by different kinds of stars in a halo with DM properties characteristic of the ones where the first star formation episode occurs. We find that either massive, metal-free and small, galactic-like stars can achieve Dark Luminosities comparable or exceeding their nuclear ones. This might have dramatic effects over the evolution of the very first stars, known as Population III.
Date: May 2, 2008
Creator: Iocco, Fabio
System: The UNT Digital Library
Correction to "Sound Velocities of Ferropericlase in the Earth?s Lower Mantle" (open access)

Correction to "Sound Velocities of Ferropericlase in the Earth?s Lower Mantle"

None
Date: May 2, 2007
Creator: Lin, J. F.; Jacobsen, S. D.; Sturhahn, W.; Jackson, J. M.; Zhao, J. & Yoo, C. S.
System: The UNT Digital Library
Assessment of fire hazards in buildings housing fusion energy experiments (open access)

Assessment of fire hazards in buildings housing fusion energy experiments

A number of materials in and within the proximity of buildings housing fusion energy experiments (FEE) were analyzed for their potential fire hazard. The materials used in this study were mostly: electrical and thermal insulations. The fire hazard of these materials was assessed in terms of their ease of ignition, heat release rate, generation of smoke, and the effect of thermal environment on the combustion behavior. Several fire protection measures for buildings housing the (FEE) projects are analyzed and as a result of this study are found to be adequate for the near term.
Date: May 2, 1978
Creator: Alvares, N. & Lipska, A.
System: The UNT Digital Library
Decentralized energy planning and consensus in energy policy (open access)

Decentralized energy planning and consensus in energy policy

This paper explores the following three propositions and their relationships: (1) that, in our pluralistic policymaking environment, we cannot solve our nation's energy problems unless we can reach agreement among a diverse group of interested parties about specific actions; (2) that, short of a manifest emergency, such a consensus is difficult to reach unless the scale of the decision-making unit is relatively small; and therefore (3) that one of the keys to an effective energy policy in the United states is to rely heavily on local and regional energy planning and decision-making. First, the paper reviews our problem of irresolution and its roots, and it summaries the policy options for resolving it. Then it explores one of those options, decentralized planning, in a little more detail. Finally, it offers some speculations about the viability of a decentralized approach to energy planninng.
Date: May 2, 1980
Creator: Wilbanks, T.J.
System: The UNT Digital Library
Characterization of transuranium actinide alloy phase diagrams (open access)

Characterization of transuranium actinide alloy phase diagrams

Alloys of Np have been studied less than those,of the neighboring elements, U and Pu; the higher actinides have received even less attention. Recent interest in {sup 237}Np, {sup 241}Am and other actinide isotopes as significant, long-lived and highly radiotoxic nuclear waste components, and particularly the roles of metallic materials new handling/separations and remediation technologies, demands that this paucity of information concerning alloy behaviors be addressed. An additional interest in these arises from the possibility of revealing fundamental properties and bonding interactions, which would further characterize the unique electronic structures (e.g., 5f electrons) of the actinide elements. The small empirical knowledge basis presently available for understanding and modeling the alloying behavior of Np is summarized here, with emphasis on our recent results for the Np-Am, Np-Zr and Np-Fe phase diag rams. In view of the limited experimental data base for neptunium and the transplutonium metals, the value of semi-empirical intermetallic bonding models for predicting actinide alloy thermodynamics is evaluated.
Date: May 2, 1994
Creator: Gibson, J. K.; Haire, R. G.; Gensini, M. M. & Ogawa, T.
System: The UNT Digital Library