Distinguishing Pu Metal from Pu Oxide Using Fast Neutron Counting (open access)

Distinguishing Pu Metal from Pu Oxide Using Fast Neutron Counting

None
Date: May 17, 2013
Creator: Verbeke, J M; Chapline, G C; Nakae, L F & Sheets, S A
Object Type: Article
System: The UNT Digital Library
Tracer Particle Locations with Curved or Arbitrary Planar Meshes (open access)

Tracer Particle Locations with Curved or Arbitrary Planar Meshes

None
Date: May 17, 2013
Creator: Yao, J
Object Type: Report
System: The UNT Digital Library
A Compact Ring Design with Tunable Momentum Compaction (open access)

A Compact Ring Design with Tunable Momentum Compaction

A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and predamping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.
Date: May 17, 2012
Creator: Sun, Y.
Object Type: Article
System: The UNT Digital Library
Integration of Heat Transfer, Stress, and Particle Trajectory Simulation (open access)

Integration of Heat Transfer, Stress, and Particle Trajectory Simulation

Calabazas Creek Research, Inc. developed and currently markets Beam Optics Analyzer (BOA) in the United States and abroad. BOA is a 3D, charged particle optics code that solves the electric and magnetic fields with and without the presence of particles. It includes automatic and adaptive meshing to resolve spatial scales ranging from a few millimeters to meters. It is fully integrated with CAD packages, such as SolidWorks, allowing seamless geometry updates. The code includes iterative procedures for optimization, including a fully functional, graphical user interface. Recently, time dependent, particle in cell capability was added, pushing particles synchronically under quasistatic electromagnetic fields to obtain particle bunching under RF conditions. A heat transfer solver was added during this Phase I program. Completed tasks include: (1) Added a 3D finite element heat transfer solver with adaptivity; (2) Determined the accuracy of the linear heat transfer field solver to provide the basis for development of higher order solvers in Phase II; (3) Provided more accurate and smoother power density fields; and (4) Defined the geometry using the same CAD model, while maintaining different meshes, and interfacing the power density field between the particle simulator and heat transfer solvers. These objectives were achieved using modern …
Date: May 17, 2012
Creator: Bui, Thuc; Read, Michael & Ives, Lawrence
Object Type: Report
System: The UNT Digital Library
Jesse Pino Profile (open access)

Jesse Pino Profile

None
Date: May 17, 2012
Creator: Pino, J
Object Type: Article
System: The UNT Digital Library
Search for Lepton-Number Violating Processes in B+ to h- l+ l+ Decays (open access)

Search for Lepton-Number Violating Processes in B+ to h- l+ l+ Decays

We have searched for the lepton-number violating processes B{sup +} {yields} h{sup -}{ell}{sup +}{ell}{sup +} with h{sup -} = K{sup -}/{pi}{sup -} and {ell}{sup +} = e{sup +}/{mu}{sup +}, using a sample of 471 {+-} 3 million B{bar B} events collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. We find no evidence for these decays and place 90% confidence level upper limits on their branching fractions B (B{sup +} {yields} {pi}{sup -}e{sup +}e{sup +}) < 2.3 x 10{sup -8}, {Beta}(B{sup +} {yields} K{sup -}e{sup +}e{sup +}) < 3.0 x 10{sup -8}, {Beta}(B{sup +} {yields} {pi}{sup -}{mu}{sup +}{mu}{sup +}) < 10.7 x 10{sup -8}, and {Beta}(B{sup +} {yields} K{sup -}{mu}{sup +}{mu}{sup +}) < 6.7 x 10{sup -8}.
Date: May 17, 2012
Creator: Lees, J.P.
Object Type: Article
System: The UNT Digital Library
Systematic Improvement of QCD Parton Showers (open access)

Systematic Improvement of QCD Parton Showers

In this contribution, we will give a brief overview of the progress that has been achieved in the field of combining matrix elements and parton showers. We exemplify this by focusing on the case of electron-positron collisions and by reporting on recent developments as accomplished within the SHERPA event generation framework.
Date: May 17, 2012
Creator: Winter, Jan; Hoeche, Stefan; Hoeth, Hendrik; Krauss, Frank; Schonherr, Marek; Zapp, Korinna et al.
Object Type: Article
System: The UNT Digital Library
Tailoring properties of carbon-nanotube-based foams by ion bombardment (open access)

Tailoring properties of carbon-nanotube-based foams by ion bombardment

None
Date: May 17, 2012
Creator: Charnvanichborikarn, S.; Shin, S. J.; Worsley, M. A. & Kucheyev, S. O.
Object Type: Article
System: The UNT Digital Library
Accounting for Unresolved Spatial Variability in Large Scale Models: Development and Evaluation of a Statistical Cloud Parameterization with Prognostic Higher Order Moments (open access)

Accounting for Unresolved Spatial Variability in Large Scale Models: Development and Evaluation of a Statistical Cloud Parameterization with Prognostic Higher Order Moments

This project focused on the variability of clouds that is present across a wide range of scales ranging from the synoptic to the millimeter. In particular, there is substantial variability in cloud properties at scales smaller than the grid spacing of models used to make climate projections (GCMs) and weather forecasts. These models represent clouds and other small-scale processes with parameterizations that describe how those processes respond to and feed back on the largescale state of the atmosphere.
Date: May 17, 2011
Creator: Pincus, Robert
Object Type: Report
System: The UNT Digital Library
A Comparison between a Minijet Model and a Glasma Flux Tube Model for Central Au-Au Collisions at sqrt NN=200 GeV (open access)

A Comparison between a Minijet Model and a Glasma Flux Tube Model for Central Au-Au Collisions at sqrt NN=200 GeV

In this paper we compare two models with central Au-Au collisions at sqrtsNN=200 GeV. The first model is a minijet model which assumes that around ~50 minijets are produced in back-to-back pairs and have an altered fragmentation functions. It is also assumed that the fragments are transparent and escape the collision zone and are detected. The second model is a glasma flux tube model which leads to flux tubes on the surface of a radial expanding fireball driven by interacting flux tubes near the center of the fireball through plasma instabilities. This internal fireball becomes an opaque hydro fluid which pushes the surface flux tubes outward. Around ~12 surfaceflux tubes remain and fragment with ~1/2 the produced particles escaping the collision zone and are detected. Both models can reproduce two particle angular correlations in the different pt1 pt2 bins. We also compare the two models for three additional effects: meson baryon ratios; the long range nearside correlation called the ridge; and the so-called mach cone effect when applied to three particle angular correlations.
Date: May 17, 2011
Creator: Longacre, R. S.
Object Type: Report
System: The UNT Digital Library
Detailed chemical kinetic reaction mechanisms for soy and rapeseed biodiesel fuels (open access)

Detailed chemical kinetic reaction mechanisms for soy and rapeseed biodiesel fuels

None
Date: May 17, 2011
Creator: Westbrook, C K; Naik, C V; Herbinet, O; Pitz, W J; Mehl, M; Sarathy, S M et al.
Object Type: Article
System: The UNT Digital Library
Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f) (open access)

Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f)

None
Date: May 17, 2011
Creator: Vogt, R.; Randrup, J.; Brown, D. A.; Descalle, M. A. & Ormand, E.
Object Type: Article
System: The UNT Digital Library
FVB Energy Inc. Technical Assistance Project (open access)

FVB Energy Inc. Technical Assistance Project

The request made by FVB asked for advice and analysis regarding the value of recapturing the braking energy of trains operating on electric light rail transit systems. A specific request was to evaluate the concept of generating hydrogen by electrolysis. The hydrogen would, in turn, power fuel cells that could supply electric energy back into the system for train propulsion or, possibly, also to the grid. To allow quantitative assessment of the potential resource, analysis focused on operations of the SoundTransit light rail system in Seattle, Washington. An initial finding was that the full cycle efficiency of producing hydrogen as the medium for capturing and reusing train braking energy was quite low (< 20%) and, therefore, not likely to be economically attractive. As flywheel energy storage is commercially available, the balance of the analysis focused the feasibility of using this alternative on the SoundTransit system. It was found that an investment in a flywheel with a 25-kWh capacity of the type manufactured by Beacon Power Corporation (BPC) would show a positive 20-year net present value (NPV) based on the current frequency of train service. The economic attractiveness of this option would increase initially if green energy subsidies or rebates were …
Date: May 17, 2011
Creator: DeSteese, John G.
Object Type: Report
System: The UNT Digital Library
GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION (open access)

GAMMA RADIATION INTERACTS WITH MELANIN TO ALTER ITS OXIDATION-REDUCTION POTENTIAL AND RESULTS IN ELECTRIC CURRENT PRODUCTION

The presence of melanin pigments in organisms is implicated in radioprotection and in some cases, enhanced growth in the presence of high levels of ionizing radiation. An understanding of this phenomenon will be useful in the design of radioprotective materials. However, the protective mechanism of microbial melanin in ionizing radiation fields has not yet been elucidated. Here we demonstrate through the electrochemical techniques of chronoamperometry, chronopotentiometry and cyclic voltammetry that microbial melanin is continuously oxidized in the presence of gamma radiation. Our findings establish that ionizing radiation interacts with melanin to alter its oxidation-reduction potential. Sustained oxidation resulted in electric current production and was most pronounced in the presence of a reductant, which extended the redox cycling capacity of melanin. This work is the first to establish that gamma radiation alters the oxidation-reduction behavior of melanin, resulting in electric current production. The significance of the work is that it provides the first step in understanding the initial interactions between melanin and ionizing radiation taking place and offers some insight for production of biomimetic radioprotective materials.
Date: May 17, 2011
Creator: Turick, C.; Ekechukwu, A. & Milliken, C.
Object Type: Article
System: The UNT Digital Library
Hanford Tank Farms Waste Certification Flow Loop Phase IV: PulseEcho Sensor Evaluation (open access)

Hanford Tank Farms Waste Certification Flow Loop Phase IV: PulseEcho Sensor Evaluation

Hanford Tank Farms Waste Certification Flow Loop Phase IV: PulseEcho Sensor Evaluation
Date: May 17, 2011
Creator: Denslow, Kayte M.; Jenks, Jeromy WJ; Bontha, Jagannadha R.; Adkins, Harold E.; Burns, Carolyn A.; Schonewill, Philip P. et al.
Object Type: Report
System: The UNT Digital Library
Impact Plate Test Problem (open access)

Impact Plate Test Problem

None
Date: May 17, 2011
Creator: Weseloh, W & Najjar, F
Object Type: Report
System: The UNT Digital Library
Optical absorption in transparent conducting oxides: Mott transition or Mahan excitons? (open access)

Optical absorption in transparent conducting oxides: Mott transition or Mahan excitons?

None
Date: May 17, 2011
Creator: Schleife, A.; Rodl, C.; Fuchs, F.; Hannewald, K. & Bechstedt, F.
Object Type: Article
System: The UNT Digital Library

Polymer Self Assembly for Electronic Devices

None
Date: May 17, 2011
Creator: Black, C.T.
Object Type: Presentation
System: The UNT Digital Library
TANK48 CFD MODELING ANALYSIS (open access)

TANK48 CFD MODELING ANALYSIS

The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four dual-nozzle slurry pumps located within the tank liquid. For the work, a Tank 48 simulation model with a maximum of four slurry pumps in operation has been developed to estimate flow patterns for efficient solid mixing. The modeling calculations were performed by using two modeling approaches. One approach is a single-phase Computational Fluid Dynamics (CFD) model to evaluate the flow patterns and qualitative mixing behaviors for a range of different modeling conditions since the model was previously benchmarked against the test results. The other is a two-phase CFD model to estimate solid concentrations in a quantitative way by solving the Eulerian governing equations for the continuous fluid and discrete solid phases over the entire fluid domain of Tank 48. The two-phase results should be considered as the preliminary scoping calculations since the model was not validated against the test results yet. A series of sensitivity calculations for different numbers of pumps and operating conditions has been performed to provide operational guidance for solids …
Date: May 17, 2011
Creator: Lee, S.
Object Type: Report
System: The UNT Digital Library
Workshop on Laser Plasma Interactions on the National Ignition Facility (open access)

Workshop on Laser Plasma Interactions on the National Ignition Facility

None
Date: May 17, 2011
Creator: Hinkel, D; Callahan, D & Glenzer, S H
Object Type: Article
System: The UNT Digital Library
Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens (open access)

Adaptation of the Biolog Phenotype MicroArrayTM Technology to Profile the Obligate Anaerobe Geobacter metallireducens

The Biolog OmniLog? Phenotype MicroArray (PM) plate technology was successfully adapted to generate a select phenotypic profile of the strict anaerobe Geobacter metallireducens (G.m.). The profile generated for G.m. provides insight into the chemical sensitivity of the organism as well as some of its metabolic capabilities when grown with a basal medium containing acetate and Fe(III). The PM technology was developed for aerobic organisms. The reduction of a tetrazolium dye by the test organism represents metabolic activity on the array which is detected and measured by the OmniLog(R) system. We have previously adapted the technology for the anaerobic sulfate reducing bacterium Desulfovibrio vulgaris. In this work, we have taken the technology a step further by adapting it for the iron reducing obligate anaerobe Geobacter metallireducens. In an osmotic stress microarray it was determined that the organism has higher sensitivity to impermeable solutes 3-6percent KCl and 2-5percent NaNO3 that result in osmotic stress by osmosis to the cell than to permeable non-ionic solutes represented by 5-20percent ethylene glycol and 2-3percent urea. The osmotic stress microarray also includes an array of osmoprotectants and precursor molecules that were screened to identify substrates that would provide osmotic protection to NaCl stress. None of the …
Date: May 17, 2010
Creator: Joyner, Dominique; Fortney, Julian; Chakraborty, Romy & Hazen, Terry
Object Type: Report
System: The UNT Digital Library

Alternations of Structure and Functional Activity of Below Ground Microbial Communities at Elevated Atmospheric Carbon Dioxide

The global atmospheric concentration of CO2 has increased by more than 30percent since the industrial revolution. Although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity have been well studied, its influences on belowground microbial communities are poorly understood and controversial. In this study, we showed a significant change in the structure and functional potential of soil microbial communities at eCO2 in a grassland ecosystem, the BioCON (Biodiversity, CO2 and Nitrogen) experimental site (http://www.biocon.umn.edu/) using a comprehensive functional gene array, GeoChip 3.0, which contains about 28,0000 probes and covers approximately 57,000 gene variants from 292 functional gene families involved in carbon, nitrogen, phosphorus and sulfur cycles as well as other functional processes. GeoChip data indicated that the functional structure of microbial communities was markedly different between ambient CO2 (aCO2) and eCO2 by detrended correspondence analysis (DCA) of all 5001 detected functional gene probes although no significant differences were detected in the overall microbial diversity. A further analysis of 1503 detected functional genes involved in C, N, P, and S cycles showed that a considerable portion (39percent) of them were only detected under either aCO2 (14percent) or eCO2 (25percent), indicating that the functional characteristics of the microbial …
Date: May 17, 2010
Creator: He, Zhili; Xu, Meiying; Deng, Ye; Kang, Sanghoon; Wu, Liyou; Van Nostrand, Joy D. et al.
Object Type: Poster
System: The UNT Digital Library
Chemical structure of vanadium-based contact formation on n-AlN (open access)

Chemical structure of vanadium-based contact formation on n-AlN

We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.
Date: May 17, 2010
Creator: Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L. et al.
Object Type: Article
System: The UNT Digital Library
Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella (open access)

Comparative Genomics Analysis and Phenotypic Characterization of Shewanella putrefaciens W3-18-1: Anaerobic Respiration, Bacterial Microcompartments, and Lateral Flagella

Respiratory versatility and psychrophily are the hallmarks of Shewanella. The ability to utilize a wide range of electron acceptors for respiration is due to the large number of c-type cytochrome genes present in the genome of Shewanella strains. More recently the dissimilatory metal reduction of Shewanella species has been extensively and intensively studied for potential applications in the bioremediation of radioactive wastes of groundwater and subsurface environments. Multiple Shewanella genome sequences are now available in the public databases (Fredrickson et al., 2008). Most of the sequenced Shewanella strains were isolated from marine environments and this genus was believed to be of marine origin (Hau and Gralnick, 2007). However, the well-characterized model strain, S. oneidensis MR-1, was isolated from the freshwater lake sediment of Lake Oneida, New York (Myers and Nealson, 1988) and similar bacteria have also been isolated from other freshwater environments (Venkateswaran et al., 1999). Here we comparatively analyzed the genome sequence and physiological characteristics of S. putrefaciens W3-18-1 and S. oneidensis MR-1, isolated from the marine and freshwater lake sediments, respectively. The anaerobic respirations, carbon source utilization, and cell motility have been experimentally investigated. Large scale horizontal gene transfers have been revealed and the genetic divergence between these …
Date: May 17, 2010
Creator: Qiu, D.; Tu, Q.; He, Zhili & Zhou, Jizhong
Object Type: Report
System: The UNT Digital Library