Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera (open access)

Monte Carlo Simulation of a Coded Aperture Thermal Neutron Camera

N/A
Date: May 8, 2011
Creator: I., Dioszegi; Salwen, C. & and Forman, I.
Object Type: Article
System: The UNT Digital Library
SUMMARY OF FY11 SULFATE RETENTION STUDIES FOR DEFENSE WASTE PROCESSING FACILITY GLASS (open access)

SUMMARY OF FY11 SULFATE RETENTION STUDIES FOR DEFENSE WASTE PROCESSING FACILITY GLASS

This report describes the results of studies related to the incorporation of sulfate in high level waste (HLW) borosilicate glass produced at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). A group of simulated HLW glasses produced for earlier sulfate retention studies was selected for full chemical composition measurements to determine whether there is any clear link between composition and sulfate retention over the compositional region evaluated. In addition, the viscosity of several glasses was measured to support future efforts in modeling sulfate solubility as a function of predicted viscosity. The intent of these studies was to develop a better understanding of sulfate retention in borosilicate HLW glass to allow for higher loadings of sulfate containing waste. Based on the results of these and other studies, the ability to improve sulfate solubility in DWPF borosilicate glasses lies in reducing the connectivity of the glass network structure. This can be achieved, as an example, by increasing the concentration of alkali species in the glass. However, this must be balanced with other effects of reduced network connectivity, such as reduced viscosity, potentially lower chemical durability, and in the case of higher sodium and aluminum concentrations, the propensity for nepheline crystallization. …
Date: May 8, 2012
Creator: Fox, K. & Edwards, T.
Object Type: Report
System: The UNT Digital Library
GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY (open access)

GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY

From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin …
Date: May 8, 2012
Creator: Millings, M.; Denham, M. & Looney, B.
Object Type: Report
System: The UNT Digital Library
Compact, Interactive Electric Vehicle Charger (open access)

Compact, Interactive Electric Vehicle Charger

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Agile Delivery of Electrical Power Technology (ADEPT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses a battery-to-grid energy distribution design as part of the "Gallium-Nitride Switch Technology for Bi-Directional Battery-to-Grid Charger Applications" project.
Date: May 8, 2012
Creator: HRL Laboratories, LLC
Object Type: Text
System: The UNT Digital Library
An investigation of exploitation versus exploration in GBEA optimization of PORS 15 and 16 Problems (open access)

An investigation of exploitation versus exploration in GBEA optimization of PORS 15 and 16 Problems

It was hypothesized that the variations in time to solution are driven by the competing mechanisms of exploration and exploitation.This thesis explores this hypothesis by examining two contrasting problems that embody the hypothesized tradeoff between exploration and exploitation. Plus one recall store (PORS) is an optimization problem based on the idea of a simple calculator with four buttons: plus, one, store, and recall. Integer addition and store are classified as operations, and one and memory recall are classified as terminals. The goal is to arrange a fixed number of keystrokes in a way that maximizes the numerical result. PORS 15 (15 keystrokes) represents the subset of difficult PORS problems and PORS 16 (16 keystrokes) represents the subset of PORS problems that are easiest to optimize. The goal of this work is to examine the tradeoff between exploitation and exploration in graph based evolutionary algorithm (GBEA) optimization. To do this, computational experiments are used to examine how solutions evolve in PORS 15 and 16 problems when solved using GBEAs. The experiment is comprised of three components; the graphs and the population, the evolutionary algorithm rule set, and the example problems. The complete, hypercube, and cycle graphs were used for this experiment. …
Date: May 8, 2012
Creator: Koch, Kaelynn
Object Type: Thesis or Dissertation
System: The UNT Digital Library
COLLABORATIVE RESEARCH: CONTINUOUS DYNAMIC GRID ADAPTATION IN A GLOBAL ATMOSPHERIC MODEL: APPLICATION AND REFINEMENT (open access)

COLLABORATIVE RESEARCH: CONTINUOUS DYNAMIC GRID ADAPTATION IN A GLOBAL ATMOSPHERIC MODEL: APPLICATION AND REFINEMENT

This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the "physics" of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited. 3a. EULAG Advances EULAG is a non-hydrostatic, parallel computational model for all-scale geophysical flows. EULAG's name derives from its two computational options: EULerian (flux form) or semi-LAGrangian (advective form). The model combines nonoscillatory forward-in-time (NFT) numerical algorithms with a robust elliptic Krylov solver. A signature feature of EULAG is that it is formulated …
Date: May 8, 2012
Creator: Gutowski, William J.; Prusa, Joseph M. & Smolarkiewicz, Piotr K.
Object Type: Report
System: The UNT Digital Library
EVALUATION OF A GEOTHERMAL PROSPECT USING A STOCHASTIC JOINT INVERSION MODELING PROCEDURE (open access)

EVALUATION OF A GEOTHERMAL PROSPECT USING A STOCHASTIC JOINT INVERSION MODELING PROCEDURE

None
Date: May 8, 2013
Creator: Tompson, A; Mellors, R; Ramirez, A; Chen, M; Dyer, K; Yang, X et al.
Object Type: Article
System: The UNT Digital Library
Comparison of ELM heat loads in snowflake and standard divertors (open access)

Comparison of ELM heat loads in snowflake and standard divertors

An analysis is given of the impact of the tokamak divertor magnetic structure on the temporal and spatial divertor heat flux from edge localized modes (ELMs). Two configurations are studied: the standard divertor where the poloidal magnetic field (B{sub p}) varies linearly with distance (r) from the magnetic null and the snowflake where B{sub p} varies quadratrically with r. Both one and two-dimensional models are used to analyze the effect of the longer magnetic field length between the midplane and the divertor plate for the snowflake that causes a temporal dilation of the ELM divertor heat flux. A second effect discussed is the appearance of a broad region near the null point where the poloidal plasma beta can substantially exceed unity, especially for the snowflake configuration during the ELM; such a condition is likely to drive additional radial ELM transport.
Date: May 8, 2012
Creator: Rognlien, T. D.; Cohen, R. H.; Ryutov, D. D. & Umansky, M. V.
Object Type: Article
System: The UNT Digital Library
Advanced Power Electronics for LED Drivers (open access)

Advanced Power Electronics for LED Drivers

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Agile Delivery of Electrical Power Technology (ADEPT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses advanced power electronics for LED drivers as part of the "Advanced Technologies for Integrated Power Electronics" project.
Date: May 8, 2012
Creator: Massachusetts Institute of Technology
Object Type: Text
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

Hackensack University Medical Center's major initiative to create a cleaner healthier and safer environment for patients, employees and the community served by the medical center is built on its commitment to protect the environment and conserve precious energy resources. Since 2004 the Medical Center launched a long term campaign to temper the negative environmental impact of proposed and existing new construction at the medical center and to improve campus wide overall energy efficiency. The plan was to begin by implementing a number of innovative and eco-friendly enhancements to the Gabrellian Women's and Children's Pavilion, in construction at the time, which would lead to Certification by the US Green Building Councils Leadership & Environmental Design (LEED) program. In addition the medical center would evaluate the feasibility of implementing a photovoltaic system in the new construction (in development and planned) to provide clean pollution free electricity. The steps taken to achieve this included conducting a feasibility study complete with architectural and engineering assessments to determine the potential for implementation of a photovoltaic system on the campus and also to conduct an energy survey that would focus on determining specific opportunities and upgrades that would lead to a healthier energy efficient interior environment …
Date: May 8, 2012
Creator: Cunning, Helen
Object Type: Report
System: The UNT Digital Library
Overview of Collisional-Threat-Mitigation Activities at Lawrence Livermore National Laboratory (open access)

Overview of Collisional-Threat-Mitigation Activities at Lawrence Livermore National Laboratory

None
Date: May 8, 2013
Creator: MIller, P; Dearborn, D; Elliott, J; Gibbard, S; Herbold, E; Howley, K et al.
Object Type: Article
System: The UNT Digital Library
Summary for Policy Makers: Intergovernmental Panel on Climate Change Special Report Renewable Energy Sources (SRREN) (open access)

Summary for Policy Makers: Intergovernmental Panel on Climate Change Special Report Renewable Energy Sources (SRREN)

The Working Group III Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) presents an assessment of the literature on the scientific, technological, environmental, economic and social aspects of the contribution of six renewable energy (RE) sources to the mitigation of climate change. It is intended to provide policy relevant information to governments, intergovernmental processes and other interested parties. This Summary for Policymakers provides an overview of the SRREN, summarizing the essential findings. The SRREN consists of 11 chapters. Chapter 1 sets the context for RE and climate change; Chapters 2 through 7 provide information on six RE technologies, and Chapters 8 through 11 address integrative issues.
Date: May 8, 2011
Creator: Arvizu, Dan; Bruckner, Thomas; Christensen, John; Devernay, Jean-Michel; Faaij , Andre; Fischedick, Manfred et al.
Object Type: Article
System: The UNT Digital Library
Northwestern University Facility for Clean Catalytic Process Research (open access)

Northwestern University Facility for Clean Catalytic Process Research

Northwestern University with DOE support created a Facility for Clean Catalytic Process Research. This facility is designed to further strengthen our already strong catalysis research capabilities and thus to address these National challenges. Thus, state-of-the art instrumentation and experimentation facility was commissioned to add far greater breadth, depth, and throughput to our ability to invent, test, and understand catalysts and catalytic processes, hence to improve them via knowledge-based design and evaluation approaches.
Date: May 8, 2013
Creator: Marks, Tobin Jay
Object Type: Report
System: The UNT Digital Library
Compton scattering gamma-ray light source modeling and optimization (open access)

Compton scattering gamma-ray light source modeling and optimization

None
Date: May 8, 2013
Creator: Wu, S. Q.; Marsh, R. A. & Hartemann, F. V.
Object Type: Article
System: The UNT Digital Library
LLNL X-band Test Station Status (open access)

LLNL X-band Test Station Status

None
Date: May 8, 2013
Creator: Marsh, R A; Albert, F; Anderson, G G; Anderson, S G; Dayton, E; Fisher, S E et al.
Object Type: Article
System: The UNT Digital Library
Solid State Electron Transfer via Bacterial Nanowires: Contributions Toward a Mechanistic Understanding of Geophysical Response of Biostimulated Subsurface (open access)

Solid State Electron Transfer via Bacterial Nanowires: Contributions Toward a Mechanistic Understanding of Geophysical Response of Biostimulated Subsurface

The degradation of organic matter by microorganisms provides a source of electrical potential or so-called 'self potential' (SP) that can be measured by using a voltmeter. During this process electrons are being produced as a waste-product and bacterial cells have to dispose of these to allow for the complete biodegradation of organic matter. Especially in anaerobic microbial communities, exo-cellular electron transfer is the most important driving force behind this process and organisms have developed different, but also similar, ways to transfer electrons to other microorganisms. Recently, it has been postulated that direct electron transfer from cell-to-cell is actually done by 'hard-wired' microorganisms. This shuttling of electrons is most likely done by certain c-type cytochromes that form the functional part of electrically conductive nanowires. In this study we investigated if nanowires can explain the geoelectrical (self potential and spectral induced polarization) signals observed at some biostimulated environments such as DOE sites. The objectives of our project are to: (1) investigate any temporal changes in the geophysical signatures (Self Potential (SP) and Induced Polarization (IP)) associated with nanowires of the bacterium Shewanella oneidensis MR-1, wild type and mtrc/omcA deletion mutant, (2) demonstrate that mutant strains of bacteria that produce nonconductive nanowires do …
Date: May 8, 2012
Creator: Atekwana, Estella
Object Type: Report
System: The UNT Digital Library
Integrated, Geothermal-CO2 Storage Reservoirs: Adaptable, Multi-Stage, Sustainable, Energy-Recovery Strategies that Reduce Carbon Intensity and Environmental Risk (open access)

Integrated, Geothermal-CO2 Storage Reservoirs: Adaptable, Multi-Stage, Sustainable, Energy-Recovery Strategies that Reduce Carbon Intensity and Environmental Risk

None
Date: May 8, 2012
Creator: Buscheck, T A; Elliot, T R; Celia, M A; Chen, M; Hao, Y; Lu, C et al.
Object Type: Article
System: The UNT Digital Library
MONTE-CARLO BURNUP CALCULATION UNCERTAINTY QUANTIFICATION AND PROPAGATION DETERMINATION (open access)

MONTE-CARLO BURNUP CALCULATION UNCERTAINTY QUANTIFICATION AND PROPAGATION DETERMINATION

MONTEBURNS is a Monte-Carlo depletion routine utilizing MCNP and ORIGEN 2.2. Uncertainties exist in the MCNP transport calculation, but this information is not passed to the depletion calculation in ORIGEN or saved. To quantify this transport uncertainty and determine how it propagates between burnup steps, a statistical analysis of a multiple repeated depletion runs is performed. The reactor model chosen is the Oak Ridge Research Reactor (ORR) in a single assembly, infinite lattice configuration. This model was burned for a 25.5 day cycle broken down into three steps. The output isotopics as well as effective multiplication factor (k-effective) were tabulated and histograms were created at each burnup step using the Scott Method to determine the bin width. It was expected that the gram quantities and k-effective histograms would produce normally distributed results since they were produced from a Monte-Carlo routine, but some of results do not. The standard deviation at each burnup step was consistent between fission product isotopes as expected, while the uranium isotopes created some unique results. The variation in the quantity of uranium was small enough that, from the reaction rate MCNP tally, round off error occurred producing a set of repeated results with slight variation. Statistical …
Date: May 8, 2011
Creator: Nichols, T.; Sternat, M. & Charlton, W.
Object Type: Article
System: The UNT Digital Library
INDEPENDENT VERIFICATION OF THE BUILDING 3550 SLAB AT OAK RIDGE NATIONAL LABORATORY OAK RIDGE, TENNESSEE (open access)

INDEPENDENT VERIFICATION OF THE BUILDING 3550 SLAB AT OAK RIDGE NATIONAL LABORATORY OAK RIDGE, TENNESSEE

The Oak Ridge Institute for Science and Education (ORISE) has completed the independent verification survey of the Building 3550 Slab. The results of this effort are provided. The objective of this verification survey is to provide independent review and field assessment of remediation actions conducted by Safety and Ecology Corporation (SEC) to document that the final radiological condition of the slab meets the release guidelines. Verification survey activities on the Building 3550 Slab that included scans, measurements, and the collection of smears. Scans for alpha, alpha plus beta, and gamma activity identified several areas that were investigated.
Date: May 8, 2012
Creator: Weaver, Phyllis C.
Object Type: Report
System: The UNT Digital Library
In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals (open access)

In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals

The parent phases of the Fe-arsenide superconductors harbor an antiferromagnetic ground state. Significantly, the Neel transition is either preceded or accompanied by a structural transition that breaks the four fold symmetry of the high-temperature lattice. Borrowing language from the field of soft condensed matter physics, this broken discrete rotational symmetry is widely referred to as an Ising nematic phase transition. Understanding the origin of this effect is a key component of a complete theoretical description of the occurrence of superconductivity in this family of compounds, motivating both theoretical and experimental investigation of the nematic transition and the associated in-plane anisotropy. Here we review recent experimental progress in determining the intrinsic in-plane electronic anisotropy as revealed by resistivity, reflectivity and ARPES measurements of detwinned single crystals of underdoped Fe arsenide superconductors in the '122' family of compounds.
Date: May 8, 2012
Creator: Fisher, Ian Randal
Object Type: Article
System: The UNT Digital Library
Forensic Analysis of samples from the Nuclear Fuel Cycle (open access)

Forensic Analysis of samples from the Nuclear Fuel Cycle

None
Date: May 8, 2013
Creator: Borg, L. & Hutcheon, I.
Object Type: Report
System: The UNT Digital Library