Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images (open access)

Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images

An algorithm for determining satellite track endpoints with sub-pixel resolution in spaced-based images is presented. The algorithm allows for significant curvature in the imaged track due to rotation of the spacecraft capturing the image. The motivation behind the subpixel endpoint determination is first presented, followed by a description of the methodology used. Results from running the algorithm on real ground-based and simulated spaced-based images are shown to highlight its effectiveness.
Date: March 7, 2011
Creator: Simms, L M
System: The UNT Digital Library
Empirical Model for Formulation of Crystal-Tolerant Hlw Glasses (open access)

Empirical Model for Formulation of Crystal-Tolerant Hlw Glasses

Historically, high-level waste (HLW) glasses have been formulated with a low liquideus temperature (T{sub L}), or temperature at which the equilibrium fraction of spinel crystals in the melt is below 1 vol % (T{sub 0.01}), nominally below 1050 C. These constraints cannot prevent the accumulation of large spinel crystals in considerably cooler regions ({approx} 850 C) of the glass discharge riser during melter idling and significantly limit the waste loading, which is reflected in a high volume of waste glass, and would result in high capital, production, and disposal costs. A developed empirical model predicts crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass, and thereby provides guidance in formulating crystal-tolerant glasses that would allow high waste loadings by keeping the spinel crystals small and therefore suspended in the glass.
Date: March 7, 2012
Creator: Kruger, A. A.; Matyas, J.; Huckleberry, A. R.; Vienna, J. D. & Rodriguez, C. A.
System: The UNT Digital Library
In-Flight Measurements of Capsule Adiabats in Laser Driven Spherical Implosions (open access)

In-Flight Measurements of Capsule Adiabats in Laser Driven Spherical Implosions

We present the first x-ray Thomson scattering measurements of temperature and density from spherically imploding matter. The shape of the Compton downscattered spectrum provides a first-principles measurement of the electron velocity distribution function, dependent on T{sub e} and the Fermi temperature T{sub F} {approx} n{sub e}{sup 2/3}. In flight compressions of Be and CH targets reach 6-13 times solid density, with T{sub e}/T{sub F} {approx} 0.4-0.7, resulting in minimum adiabats of {approx}1.6-2. These measurements are consistent with low-entropy implosions and predictions by simulations using radiation-hydrodynamic modeling.
Date: March 7, 2011
Creator: Kritcher, A L; Doppner, T; Fortman, C; Ma, T; Landen, O L; Wallace, R et al.
System: The UNT Digital Library
Optimization of Direct Ionization of CO2 by Controlling the Gas Flow Inside of a Beam-Target (open access)

Optimization of Direct Ionization of CO2 by Controlling the Gas Flow Inside of a Beam-Target

We designed and optimized a target that directs a CO{sub 2} pulse onto a Ti surface where a Cs{sup +} sputtering beam ionizes the CO{sub 2} to generate C{sup -}. These targets will be used for the direct ionization of CO{sub 2} pulses to enable the measurement of carbon isotope ratios in real time. The design was based on the results of Comsol{trademark} simulations of the target configurations.
Date: March 7, 2011
Creator: Salazar Quintero, G A & Ognibene, T
System: The UNT Digital Library
Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand (open access)

Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand

Uranyl complexes of a bis(methylterephthalamide) ligand (LH{sub 4}) have been synthesized and characterized by X-ray crystallography. The structure is an unexpected [Me{sub 4}N]{sub 8}[L(UO{sub 2})]{sub 4} tetramer, formed via coordination of the two MeTAM units of L to two uranyl moieties. Addition of KOH to the tetramer gave the corresponding monomeric uranyl methoxide species [Me{sub 4}N]K{sub 2}[LUO{sub 2}(OMe)].
Date: March 7, 2011
Creator: Ni, Chengbao; Shuh, David & Raymond, Kenneth
System: The UNT Digital Library
Underwater Blast Experiments and Modeling for Shock Mitigation (open access)

Underwater Blast Experiments and Modeling for Shock Mitigation

A simple but novel mitigation concept to enforce standoff distance and reduce shock loading on a vertical, partially-submerged structure is evaluated using scaled aquarium experiments and numerical modeling. Scaled, water tamped explosive experiments were performed using three gallon aquariums. The effectiveness of different mitigation configurations, including air-filled media and an air gap, is assessed relative to an unmitigated detonation using the same charge weight and standoff distance. Experiments using an air-filled media mitigation concept were found to effectively dampen the explosive response of the aluminum plate and reduce the final displacement at plate center by approximately half. The finite element model used for the initial experimental design compares very well to the experimental DIC results both spatially and temporally. Details of the experiment and finite element aquarium models are described including the boundary conditions, Eulerian and Lagrangian techniques, detonation models, experimental design and test diagnostics.
Date: March 7, 2010
Creator: Glascoe, L; McMichael, L; Vandersall, K & Margraf, J
System: The UNT Digital Library
Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor (open access)

Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor

The scrape-off layer plasma at the tokamak region is characterized by open field lines and often contains large variations in plasma properties along these field-lines. Proper characterization of local plasma conditions is critical to assessing plasma-material interaction processes occuring at the target. Langmuir probes are frequently employed in tokamak divertors but are challenging to interpretation. A kinetic interpretation for Langmuir probes in NSTX has yielded non-Maxwellian electron distributions in the divertor characterized by cool bulk populations and energetic tail populations with temperatures of 2-4 times the bulk. Spectroscopic analysis and modeling confirms the bulk plasma temperature and density which can only be obtained with the kinetic interpretation
Date: March 7, 2013
Creator: M.A. Jaworski, et. al.
System: The UNT Digital Library
Mulard: A Multigroup Thermal Radiation Diffusion Mini-Application (open access)

Mulard: A Multigroup Thermal Radiation Diffusion Mini-Application

None
Date: March 7, 2012
Creator: Brunner, T A
System: The UNT Digital Library
JINA Workshop Nuclear Physics in Hot Dense Dynamic Plasmas (open access)

JINA Workshop Nuclear Physics in Hot Dense Dynamic Plasmas

Measuring NEET and NEEC is relevant for probing stellar cross-sections and testing atomic models in hot plasmas. Using NEEC and NEET we can excite nuclear levels in laboratory plasmas: (1) NIF: Measure effect of excited nuclear levels on (n,{gamma}) cross-sections, 60% and never been measured; (2) Omega, Test cross-sections for creating these excited levels via NEEC and NEET. Will allow us to test models that estimate resonance overlap of atomic states with the nucleus: (1) Average Atom model (AA) (CEA&LLNL), single average wave-function potential; (2) Super Transition Array (STA) model (LLNL), More realistic individual configuration potentials NEET experimental data is scarce and not in a plasma environment, NEEC has not yet been observed.
Date: March 7, 2011
Creator: Kritcher, A L; Cerjan, C; Landen, O; Libby, S; Chen, M; Wilson, B et al.
System: The UNT Digital Library
An Investigation of X-ray Luminosity versus Crystalline Powder Granularity (open access)

An Investigation of X-ray Luminosity versus Crystalline Powder Granularity

At the High-throughput Discovery of Scintillator Materials Facility at Lawrence Berkeley National Laboratory, scintillators are synthesized by solid-state reaction or melt mixing, forming crystalline powders. These powders are formed in various granularity and the crystal grain size affects the apparent luminosity of the scintillator. To accurately predict a "full-size" scintillator's crystal luminosity, the crystal luminosity as a function of crystal granularity size has to be known. In this study, we examine Bi{sub 4}Ge{sub 3}O{sub 12} (BGO), Lu{sub 2}SiO{sub 5}:Ce (LSO), YAlO{sub 3}:Ce (YAP:Ce), and CsBa{sub 2}I{sub 5}:Eu{sup 2+} (CBI) luminosities as a function of crystalline grain size. The highest luminosities were measured for 600- to 1000-{micro}m crystal grain sizes for BGO and LSO, for 310- to 600-{micro}m crystal grain sizes for CBI, and for crystal grains larger than 165{micro}m for YAP:Ce. Crystal grains that were larger than 1 mm had a lower packing fraction, and smaller grains were affected by internal scattering. We measured a 34% decrease in luminosity for BGO when decreasing from the 600- to 1000- {micro}m crystal grain size range down to the 20- to 36-{micro}m range. The corresponding luminosity decrease for LSO was 44% for the same grain size decrease. YAP:Ce exhibited a luminosity decrease of …
Date: March 7, 2012
Creator: Borade, Ramesh & Bourret-Courchesne, Edith
System: The UNT Digital Library
Response to Comments on "A Bacterium That Can Grow Using Arsenic Instead of Phosphorus" (open access)

Response to Comments on "A Bacterium That Can Grow Using Arsenic Instead of Phosphorus"

Concerns have been raised about our recent study describing a bacterium that can grow using arsenic (As) instead of phosphorus (P). Our data suggested that As could act as a substitute for P in major biomolecules in this organism. Although the issues raised are of investigative interest, we contend that they do not invalidate our conclusions. We argue that while no single line of evidence we presented was sufficient to support our interpretation of the data, taken as an entire dataset we find no plausible alternative to our conclusions. Here we reply to the critiques and provide additional arguments supporting the assessment of the data we reported.
Date: March 7, 2011
Creator: Wolfe-Simon, F.; Blum, J. S.; Kulp, T. R.; Gordon, G. W.; Hoeft, S. E.; Pett-Ridge, J. et al.
System: The UNT Digital Library
Cerenkov Radiator Driven by a Superconducting RF Electron Gun (open access)

Cerenkov Radiator Driven by a Superconducting RF Electron Gun

The Naval Postgraduate School (NPS), Niowave, Inc., and Boeing have recently demonstrated operation of the first superconducting RF electron gun based on a quarter wave resonator structure. In preliminary tests, this gun has produced 10 ps long bunches with charge in excess of 78 pC, and with beam energy up to 396 keV. Initial testing occurred at Niowave's Lansing, MI facility, but the gun and diagnostic beam line are planned for installation in California in the near future. The design of the diagnostic beam line is conducive to the addition of a Cerenkov radiator without interfering with other beam line operations. Design and simulations of a Cerenkov radiator, consisting of a dielectric lined waveguide will be presented. The dispersion relation for the structure is determined and the beam interaction is studied using numerical simulations. The characteristics of the microwave radiation produced in both the short and long bunch regimes will be presented.
Date: March 7, 2011
Creator: Poole, B R & Harris, J R
System: The UNT Digital Library
CO Adsorption on Noble Metal Clusters: Local Environment Effects (open access)

CO Adsorption on Noble Metal Clusters: Local Environment Effects

Article on CO adsorption on noble metal clusters and local environmental effects.
Date: March 7, 2011
Creator: Buongiorno Nardelli, Marco; Morrow, Brian H.; Resasco, Daniel E. & Striolo, Alberto
System: The UNT Digital Library
Comment on "Measurement and Correlation of Solubilities of (Z)-2-(2-Aminothiazol-4-yl)-2-methoxyiminoacetic Acid in Different Pure Solvents and Binary Mixtures of Water + (Ethanol, Methanol, or Glycol)" (open access)

Comment on "Measurement and Correlation of Solubilities of (Z)-2-(2-Aminothiazol-4-yl)-2-methoxyiminoacetic Acid in Different Pure Solvents and Binary Mixtures of Water + (Ethanol, Methanol, or Glycol)"

Article commenting on an article titled, "Measurement and correlation of solubilities of (Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid in different pure solvents and binary mixtures of water + (ethanol, methanol, or glycol)," published in March 2011.
Date: March 7, 2012
Creator: Jouyban, Abolghasem; Fakhree, Mohammad Amin Abolghassemi & Acree, William E. (William Eugene)
System: The UNT Digital Library
Comments on "Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra" (open access)

Comments on "Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra"

Article commenting on "Role of Anions (tetrafluoroborate, perchlorate) of tetrabutylammonium salts in determining solvation effects prevailing in industrially essential solvents probed by conductance and FT-IR spectra.
Date: March 7, 2014
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Opting Out: Parents Creating Contested Spaces to Challenge Standardized Tests (open access)

Opting Out: Parents Creating Contested Spaces to Challenge Standardized Tests

This article explores how the opt-out movement has responded to the combination of a stringent federal policy with weak and often variable implementation among the states.
Date: March 7, 2016
Creator: Mitra, Dana; Mann, Bryan & Hlavacik, Mark
System: The UNT Digital Library