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Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping

Description: Magnetic (Ga{sub x}Fe{sub 1-x}){sub 3}O{sub 4} nanoparticles with 5%-33% gallium doping (x = 0.05-0.33) were measured using x-ray absorption spectroscopy and x-ray magnetic circular dichroism to determine that the Ga dopant is substituting for Fe{sub 3+} as Ga{sub 3+} in the tetrahedral A-site of the spinel structure, resulting in an overall increase in the total moment of the material. Frequency-dependent alternating-current magnetic susceptibility measurements showed these particles to be wea… more
Date: October 22, 2010
Creator: Pool, V. L.; Klem, M. T.; Chorney, C. L.; Arenholz, E. & Idzerda, Y.U.
Partner: UNT Libraries Government Documents Department
open access

From many body wee partons dynamics to perfect fluid: a standard model for heavy ion collisions

Description: We discuss a standard model of heavy ion collisions that has emerged both from experimental results of the RHIC program and associated theoretical developments. We comment briefly on the impact of early results of the LHC program on this picture. We consider how this standard model of heavy ion collisions could be solidified or falsified in future experiments at RHIC, the LHC and a future Electro-Ion Collider.
Date: July 22, 2010
Creator: Venugopalan, R.
Partner: UNT Libraries Government Documents Department
open access

Analysis of the National Ignition Facility Ignition Hohlraum Energetics Experiments

Description: A series of forty experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] to study energy balance and implosion symmetry in reduced- and full-scale ignition hohlraums was shot at energies up to 1.3 MJ. This paper reports the findings of the analysis of the ensemble of experimental data obtained that has produced an improved model for simulating ignition hohlraums. Last year the first observation in a NIF hohlraum of energy transfer between cones… more
Date: November 22, 2010
Creator: Town, R. J.; Rosen, M. D.; Michel, P. A.; Divol, L.; Moody, J. D.; Kyrala, G. A. et al.
Partner: UNT Libraries Government Documents Department
open access

A molecularly defined duplication set for the X chromosome of Drosophila melanogaster

Description: We describe a molecularly defined duplication kit for the X chromosome of Drosophila melanogaster. A set of 408 overlapping P[acman] BAC clones was used to create small duplications (average length 88 kb) covering the 22-Mb sequenced portion of the chromosome. The BAC clones were inserted into an attP docking site on chromosome 3L using C31 integrase, allowing direct comparison of different transgenes. The insertions complement 92% of the essential and viable mutations and deletions tested, dem… more
Date: July 22, 2010
Creator: Venken, Koen J. T.; Popodi, Ellen; Holtzman, Stacy L.; Schulze, Karen L.; Park, Soo; Carlson, Joseph W. et al.
Partner: UNT Libraries Government Documents Department
open access

A Proposal for User-defined Reductions in OpenMP

Description: Reductions are commonly used in parallel programs to produce a global result from partial results computed in parallel. Currently, OpenMP only supports reductions for primitive data types and a limited set of base language operators. This is a significant limitation for those applications that employ user-defined data types (e. g., objects). Implementing manual reduction algorithms makes software development more complex and error-prone. Additionally, an OpenMP runtime system cannot optimize a … more
Date: March 22, 2010
Creator: Duran, A; Ferrer, R; Klemm, M; de Supinski, B R & Ayguade, E
Partner: UNT Libraries Government Documents Department
open access

Radiochemistry diagnostics for the National Ignition Facility

Description: Radiochemistry-based techniques will be an important complement to x-ray implosion diagnostics. Simulations demonstrate the value of alpha-induced or deuteron-induced reactions as a direct measurement of static mix contamination in DT-filled ignition capsules. In this proceedings we examine to what extent neutron-induced reactions might be highly correlated with the energetically down-scattered neutron fraction which is, in turn, related to the critical quantity of fuel areal density, {rho}R. A… more
Date: February 22, 2010
Creator: Hoffman, R. D.; Cerjan, C. J.; Shaughnessy, D. A.; Moody, K. J.; Nelson, S. L.; Bernstein, L. A. et al.
Partner: UNT Libraries Government Documents Department
open access

A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation

Description: We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have bee… more
Date: December 22, 2010
Creator: Bailey, T S; Chang, J H; Warsa, J S & Adams, M L
Partner: UNT Libraries Government Documents Department
open access

The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one)

Description: A series of bis(3-hydroxy-N-methyl-pyridin-2-one) ligands was synthesized, and their respective uranyl complexes were characterized by single crystal X-ray diffraction analyses. These structures were inspected for high-energy conformations and evaluated using a series of metrics to measure co-planarity of chelating moieties with each other and the uranyl coordination plane, as well as to measure coordinative crowding about the uranyl dication. Both very short (ethyl, 3,4-thiophene and o-phenyle… more
Date: April 22, 2010
Creator: Szigethy, Geza & Raymond, Kenneth
Partner: UNT Libraries Government Documents Department
open access

Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

Description: A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident pr… more
Date: April 22, 2010
Creator: Higginson, D. P.; McNaney, J. M.; Swift, D. C.; Bartal, T.; Hey, D. S.; Pape, S. L. et al.
Partner: UNT Libraries Government Documents Department
open access

Bacillus anthracis genome organization in light of whole transcriptome sequencing

Description: Emerging knowledge of whole prokaryotic transcriptomes could validate a number of theoretical concepts introduced in the early days of genomics. What are the rules connecting gene expression levels with sequence determinants such as quantitative scores of promoters and terminators? Are translation efficiency measures, e.g. codon adaptation index and RBS score related to gene expression? We used the whole transcriptome shotgun sequencing of a bacterial pathogen Bacillus anthracis to assess corre… more
Date: March 22, 2010
Creator: Martin, Jeffrey; Zhu, Wenhan; Passalacqua, Karla D.; Bergman, Nicholas & Borodovsky, Mark
Partner: UNT Libraries Government Documents Department
open access

Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate

Description: New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimen… more
Date: January 22, 2010
Creator: Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J & Mehl, M
Partner: UNT Libraries Government Documents Department
open access

Nebular mixing constrained by the Stardust samples

Description: Using X-ray microprobe analysis of samples from comet Wild 2 returned by the Stardust mission, we determine that the crystalline Fe-bearing silicate fraction in this Jupiter-family comet is greater than 0.5. Assuming this mixture is a composite of crystalline inner solar system material and amorphous cold molecular cloud material, we deduce that more than half of Wild 2 has been processed in the inner solar system. Several models exist that explain the presence of crystalline materials in comet… more
Date: March 22, 2010
Creator: OGLIORE, R. C.; WESTPHAL, A. J.; GAINSFORTH, Z.; BUTTERWORTH, A. L.; FAKRA, S. C. & Marcus, Matthew A.
Partner: UNT Libraries Government Documents Department
open access

FLUX MEASUREMENTS FROM A TALL TOWER IN A COMPLEX LANDSCAPE

Description: The accuracy and representativeness of flux measurements from a tall tower in a complex landscape was assessed by examining the vertical and sector variability of the ratio of wind speed to momentum flux and the ratio of vertical advective to eddy flux of heat. The 30-60 m ratios were consistent with theoretical predictions which indicate well mixed flux footprints. Some variation with sector was observed that were consistent with upstream roughness. Vertical advection was negligible compared w… more
Date: July 22, 2010
Creator: Kurzeja, R.; Weber, A.; Chiswell, S. & Parker, M.
Partner: UNT Libraries Government Documents Department
open access

Progress on the NSTX Center Stack Upgrade

Description: The National Spherical Torus Experiment (NSTX) will be upgraded to provide increased toroidal field, plasma current and pulse length. This involves the replacement of the so-called center stack, including the inner legs of the Toroidal Field (TF) coil, the Ohmic Heating (OH) coil, and the inner Poloidal Field (PF) coils. In addition the increased performance of the upgrade requires qualification of remaining existing components for higher loads. Initial conceptual design efforts were based on w… more
Date: September 22, 2010
Creator: Dudek, L.; Chrzanowski, J.; Heitzenroeder, P.; Mangra, D.; Neumeyer, C.; Smith, M. et al.
Partner: UNT Libraries Government Documents Department
open access

A suspended-particle rosette multi-sampler for discrete biogeochemical sampling in low-particle-density waters

Description: To enable detailed investigations of early stage hydrothermal plume formation and abiotic and biotic plume processes we developed a new oceanographic tool. The Suspended Particulate Rosette sampling system has been designed to collect geochemical and microbial samples from the rising portion of deep-sea hydrothermal plumes. It can be deployed on a remotely operated vehicle for sampling rising plumes, on a wire-deployed water rosette for spatially discrete sampling of non-buoyant hydrothermal pl… more
Date: June 22, 2010
Creator: Breier, J. A.; Rauch, C. G.; McCartney, K.; Toner, B. M.; Fakra, S. C.; White, S. N. et al.
Partner: UNT Libraries Government Documents Department
open access

Probing Compositional Variation within Hybrid Nanostructures

Description: We present a detailed analysis of the structural and magnetic properties of solution-grown PtCo-CdS hybrid structures in comparison to similar free-standing PtCo alloy nanoparticles. X-ray absorption spectroscopy is utilized as a sensitive probe for identifying subtle differences in the structure of the hybrid materials. We found that the growth of bimetallic tips on a CdS nanorod substrate leads to a more complex nanoparticle structure composed of a PtCo alloy core and thin CoO shell. The core… more
Date: June 22, 2010
Creator: Yuhas, Benjamin D.; Habas, Susan E.; Fakra, Sirine C. & Mokari, Taleb
Partner: UNT Libraries Government Documents Department
open access

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

Description: Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial … more
Date: June 22, 2010
Creator: Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David & Banfield, Jillian F.
Partner: UNT Libraries Government Documents Department
open access

Use of Micro X-Ray Absorption Spectroscopy and Diffraction to Delineate Cr(VI) Speciation in COPR

Description: The speciation of Cr(VI) in Cromite Ore Processing Residue was investigated by means of bulk XRD, and a combination of micro-XRF, -XAS and -XRD at the Advanced Light Source (ALS), Berkeley, CA, U.S.A.. Bulk XRD yielded one group of phases that contained explicitly Cr(VI) in their structure, Calcium Aluminum Chromium Oxide Hydrates, accounting for 60% of the total Cr(VI). Micro-analyses at ALS yielded complimentary information, confirming that hydrogarnets and hydrotalcites, two mineral groups t… more
Date: June 22, 2010
Creator: Chrysochoou, M.; Moon, D. H.; Fakra, S.; Marcus, M.; Dermatas, D. & Christodoulatos, C.
Partner: UNT Libraries Government Documents Department
open access

SAR Imagery Segmentation by Statistical Region Growing and Hierarchical Merging

Description: This paper presents an approach to accomplish synthetic aperture radar (SAR) image segmentation, which are corrupted by speckle noise. Some ordinary segmentation techniques may require speckle filtering previously. Our approach performs radar image segmentation using the original noisy pixels as input data, eliminating preprocessing steps, an advantage over most of the current methods. The algorithm comprises a statistical region growing procedure combined with hierarchical region merging to ex… more
Date: May 22, 2010
Creator: Ushizima, Daniela Mayumi; Carvalho, E. A.; Medeiros, F. N. S.; Martins, C. I. O.; Marques, R. C. P. & Oliveira, I. N. S.
Partner: UNT Libraries Government Documents Department
open access

Non-Universality of Transverse Momentum Dependent Parton Distributions at Small-x

Description: We study the universality of the transverse momentum dependent parton distributions at small-x, by comparing the initial/final state interaction effects in dijet-correlation in pA collisions with that in deep inelastic lepton nucleus scattering. We demonstrate the non-universality by an explicit calculation in a particular model where the multiple gauge boson exchange contributions are summed up to all orders. We furthercomment on the implications of our results on the theoretical interpretatio… more
Date: February 22, 2010
Creator: Xiao, Bowen & Yuan, Feng
Partner: UNT Libraries Government Documents Department
open access

Building Energy Information Systems: User Case Studies

Description: Measured energy performance data are essential to national efforts to improve building efficiency, as evidenced in recent benchmarking mandates, and in a growing body of work that indicates the value of permanent monitoring and energy information feedback. This paper presents case studies of energy information systems (EIS) at four enterprises and university campuses, focusing on the attained energy savings, and successes and challenges in technology use and integration. EIS are broadly defined… more
Date: March 22, 2010
Creator: Granderson, Jessica; Piette, Mary Ann & Ghatikar, Girish
Partner: UNT Libraries Government Documents Department
open access

CgWind: A high-order accurate simulation tool for wind turbines and wind farms

Description: CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also prov… more
Date: February 22, 2010
Creator: Chand, K K; Henshaw, W D; Lundquist, K A & Singer, M A
Partner: UNT Libraries Government Documents Department
open access

Combining Spatial-Temporal and Phylogenetic Analysis Approaches for Improved Understanding on Global H5N1 Transmission

Description: This article reports an interdisciplinary effort that combines the geospatial informatics approach with a bioinformatics approach to form an improved understanding on the transmission mechanisms of H5N1 virus.
Date: October 22, 2010
Creator: Liang, Lu; Xu, Bing; Chen, Yanlei; Liu, Yang; Cao, Wuchun; Fang, Liqun et al.
Partner: UNT College of Arts and Sciences
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