Crystal Williams NNSA Essay (open access)

Crystal Williams NNSA Essay

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Date: August 22, 2013
Creator: Williams, C
Object Type: Report
System: The UNT Digital Library
Up Sector of Minimal Flavor Violation: Top-Quark Properties and Direct D Meson CP Violation (open access)

Up Sector of Minimal Flavor Violation: Top-Quark Properties and Direct D Meson CP Violation

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Date: August 22, 2013
Creator: Bai, Yang; /Wisconcin U., Madison; Berger, Joshua; Hewett, JoAnne L.; Li, Ye & /SLAC
Object Type: Article
System: The UNT Digital Library
High Performance Cathodes for Li-Air Batteries (open access)

High Performance Cathodes for Li-Air Batteries

The overall objective of this project was to develop and fabricate a multifunctional cathode with high activities in acidic electrolytes for the oxygen reduction and evolution reactions for Li-air batteries. It should enable the development of Li-air batteries that operate on hybrid electrolytes, with acidic catholytes in particular. The use of hybrid electrolytes eliminates the problems of lithium reaction with water and of lithium oxide deposition in the cathode with sole organic electrolytes. The use of acid electrolytes can eliminate carbonate formation inside the cathode, making air breathing Li-air batteries viable. The tasks of the project were focused on developing hierarchical cathode structures and bifunctional catalysts. Development and testing of a prototype hybrid Li-air battery were also conducted. We succeeded in developing a hierarchical cathode structure and an effective bifunctional catalyst. We accomplished integrating the cathode with existing anode technologies and made a pouch prototype Li-air battery using sulfuric acid as catholyte. The battery cathodes contain a nanoscale multilayer structure made with carbon nanotubes and nanofibers. The structure was demonstrated to improve battery performance substantially. The bifunctional catalyst developed contains a conductive oxide support with ultra-low loading of platinum and iridium oxides. The work performed in this project has been …
Date: August 22, 2013
Creator: Xing, Yangchuan
Object Type: Report
System: The UNT Digital Library
THE APPLICATION OF A STATISTICAL DOWNSCALING PROCESS TO DERIVE 21{sup ST} CENTURY RIVER FLOW PREDICTIONS USING A GLOBAL CLIMATE SIMULATION (open access)

THE APPLICATION OF A STATISTICAL DOWNSCALING PROCESS TO DERIVE 21{sup ST} CENTURY RIVER FLOW PREDICTIONS USING A GLOBAL CLIMATE SIMULATION

The ability of water managers to maintain adequate supplies in coming decades depends, in part, on future weather conditions, as climate change has the potential to alter river flows from their current values, possibly rendering them unable to meet demand. Reliable climate projections are therefore critical to predicting the future water supply for the United States. These projections cannot be provided solely by global climate models (GCMs), however, as their resolution is too coarse to resolve the small-scale climate changes that can affect hydrology, and hence water supply, at regional to local scales. A process is needed to ‘downscale’ the GCM results to the smaller scales and feed this into a surface hydrology model to help determine the ability of rivers to provide adequate flow to meet future needs. We apply a statistical downscaling to GCM projections of precipitation and temperature through the use of a scaling method. This technique involves the correction of the cumulative distribution functions (CDFs) of the GCM-derived temperature and precipitation results for the 20{sup th} century, and the application of the same correction to 21{sup st} century GCM projections. This is done for three meteorological stations located within the Coosa River basin in northern Georgia, …
Date: August 22, 2013
Creator: Werth, D. & Chen, K. F.
Object Type: Report
System: The UNT Digital Library
X-ray diffraction diagnostic design for the National Ignition Facility (open access)

X-ray diffraction diagnostic design for the National Ignition Facility

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Date: August 22, 2013
Creator: Ahmed, M F; Ayers, J; House, A; Lamb, Z; Swift, R & Swift, D
Object Type: Article
System: The UNT Digital Library
COLLABORATIVE RESEARCH:USING ARM OBSERVATIONS & ADVANCED STATISTICAL TECHNIQUES TO EVALUATE CAM3 CLOUDS FOR DEVELOPMENT OF STOCHASTIC CLOUD-RADIATION (open access)

COLLABORATIVE RESEARCH:USING ARM OBSERVATIONS & ADVANCED STATISTICAL TECHNIQUES TO EVALUATE CAM3 CLOUDS FOR DEVELOPMENT OF STOCHASTIC CLOUD-RADIATION

The long-range goal of several past and current projects in our DOE-supported research has been the development of new and improved parameterizations of cloud-radiation effects and related processes, using ARM data, and the implementation and testing of these parameterizations in global models. The main objective of the present project being reported on here has been to develop and apply advanced statistical techniques, including Bayesian posterior estimates, to diagnose and evaluate features of both observed and simulated clouds. The research carried out under this project has been novel in two important ways. The first is that it is a key step in the development of practical stochastic cloud-radiation parameterizations, a new category of parameterizations that offers great promise for overcoming many shortcomings of conventional schemes. The second is that this work has brought powerful new tools to bear on the problem, because it has been a collaboration between a meteorologist with long experience in ARM research (Somerville) and a mathematician who is an expert on a class of advanced statistical techniques that are well-suited for diagnosing model cloud simulations using ARM observations (Shen).
Date: August 22, 2013
Creator: Somerville, Richard
Object Type: Report
System: The UNT Digital Library
Crystalline Ceramic Waste Forms: Comparison Of Reference Process For Ceramic Waste Form Fabrication (open access)

Crystalline Ceramic Waste Forms: Comparison Of Reference Process For Ceramic Waste Form Fabrication

The research conducted in this work package is aimed at taking advantage of the long term thermodynamic stability of crystalline ceramics to create more durable waste forms (as compared to high level waste glass) in order to reduce the reliance on engineered and natural barrier systems. Durable ceramic waste forms that incorporate a wide range of radionuclides have the potential to broaden the available disposal options and to lower the storage and disposal costs associated with advanced fuel cycles. Assemblages of several titanate phases have been successfully demonstrated to incorporate radioactive waste elements, and the multiphase nature of these materials allows them to accommodate variation in the waste composition. Recent work has shown that they can be produced from a melting and crystallization process. The objective of this report is to explore the phase formation and microstructural differences between lab scale melt processing in varying gas environments with alternative densification processes such as Hot Pressing (HP) and Spark Plasma Sintering (SPS). The waste stream used as the basis for the development and testing is a simulant derived from a combination of the projected Cs/Sr separated stream, the Trivalent Actinide - Lanthanide Separation by Phosphorous reagent Extraction from Aqueous Komplexes (TALSPEAK) …
Date: August 22, 2013
Creator: Brinkman, K. S.; Marra, J. C.; Amoroso, J. & Tang, M.
Object Type: Report
System: The UNT Digital Library
Determination Of Reportable Radionuclides For DWPF Sludge Batch 7B (Macrobatch 9) (open access)

Determination Of Reportable Radionuclides For DWPF Sludge Batch 7B (Macrobatch 9)

The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: …
Date: August 22, 2013
Creator: Crawford, C. L. & DiPrete, D. P.
Object Type: Report
System: The UNT Digital Library
Design and implementation of Dilation X-ray Imager for National Ignition Facility "DIXI" (open access)

Design and implementation of Dilation X-ray Imager for National Ignition Facility "DIXI"

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Date: August 22, 2013
Creator: Ayers, M. J.; Bell, P. M.; Bradley, D.; Chung, M.; Felker, B.; Hares, J. et al.
Object Type: Article
System: The UNT Digital Library
Electron-Mediated Relaxation Following Ultrafast Pumping of Strongly Correlated Materials: Model Evidence of a Correlation-Tuned Crossover between Thermal and Nonthermal States (open access)

Electron-Mediated Relaxation Following Ultrafast Pumping of Strongly Correlated Materials: Model Evidence of a Correlation-Tuned Crossover between Thermal and Nonthermal States

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Date: August 22, 2013
Creator: Moritz, B.; /SIMES, Stanford /SLAC /North Dakota U. /Northern Illinois U.; Kemper, A.F.; Sentef, M.; Devereaux, T.P.; /SIMES, Stanford /SLAC et al.
Object Type: Article
System: The UNT Digital Library
Characterization of a megapixel CMOS charge dump and read camera (open access)

Characterization of a megapixel CMOS charge dump and read camera

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Date: August 22, 2013
Creator: Kimbrough, J R; Bell, P M; Datte, P S; Thao, M S; de Dios, E & Peters, A S
Object Type: Article
System: The UNT Digital Library
Particle Physics-Final Report (open access)

Particle Physics-Final Report

Final Report for DOE Grant No. DE-FG02-90ER40546 "Experimental/Theoretical Particle Physics"
Date: August 22, 2013
Creator: Kuti, Julius
Object Type: Report
System: The UNT Digital Library
DHS HS-STEM Summer Report (open access)

DHS HS-STEM Summer Report

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Date: August 22, 2013
Creator: Patel, Y H; Conway, A M & Swanberg, E L
Object Type: Report
System: The UNT Digital Library
Active Flow Control on Bidirectional Rotors for Tidal MHK Applications (open access)

Active Flow Control on Bidirectional Rotors for Tidal MHK Applications

A marine and hydrokinetic (MHK) tidal turbine extracts energy from tidal currents, providing clean, sustainable electricity generation. In general, all MHK conversion technologies are confronted with significant operational hurdles, resulting in both increased capital and operations and maintenance (O&M) costs. To counter these high costs while maintaining reliability, MHK turbine designs can be simplified. Prior study found that a tidal turbine could be cost-effectively simplified by removing blade pitch and rotor/nacelle yaw. Its rotor would run in one direction during ebb and then reverse direction when the current switched to flood. We dubbed such a turbine a bidirectional rotor tidal turbine (BRTT). The bidirectional hydrofoils of a BRTT are less efficient than conventional hydrofoils and capture less energy, but the elimination of the pitch and yaw systems were estimated to reduce levelized cost of energy by 7.8%-9.6%. In this study, we investigated two mechanisms for recapturing some of the performance shortfall of the BRTT. First, we developed a novel set of hydrofoils, designated the yy series, for BRTT application. Second, we investigated the use of active flow control via microtabs. Microtabs are small deployable/retractable tabs, typically located near the leading or trailing edge of an air/hydrofoil with height on the …
Date: August 22, 2013
Creator: Shiu, Henry & van Dam, Cornelis P.
Object Type: Report
System: The UNT Digital Library
A Search for the Rare Decays B \to pi l+l- and B0 \to eta l+l- (open access)

A Search for the Rare Decays B \to pi l+l- and B0 \to eta l+l-

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Date: August 22, 2013
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Grauges, E.; /Barcelona U., ECM et al.
Object Type: Article
System: The UNT Digital Library