Understanding Size Effect in Cleavage Cracking in Thin Materials (open access)

Understanding Size Effect in Cleavage Cracking in Thin Materials

In a specially designed tensile fracture experiment on bicrysal thin films, it was discovered that the fracture toughness of a thin film is not a material constant; rather, as the film becomes thinner it decreases much faster than the prediction of conventional theory. A detailed analysis revealed that this is caused by the mismatch of crystalline structures and, more importantly, with an appropriate crystalline orientation distribution the decrease may be suppressed. This result shed light on the fundamentals of crystal behaviors in pressurized matters. It also provides a promising solution to minimize unexpected failures in nano/micro-electromechanical systems, and therefore is of immense technological importance.
Date: February 22, 2013
Creator: Qiao, Yu
Object Type: Report
System: The UNT Digital Library
Pediatric Clinical Proteomics Center (open access)

Pediatric Clinical Proteomics Center

None
Date: February 22, 2013
Creator: Klein, Jon B
Object Type: Report
System: The UNT Digital Library
Effect of Shim Arm Depletion in the NBSR (open access)

Effect of Shim Arm Depletion in the NBSR

The cadmium shim arms in the NBSR undergo burnup during reactor operation and hence, require periodic replacement. Presently, the shim arms are replaced after every 25 cycles to guarantee they can maintain sufficient shutdown margin. Two prior reports document the expected change in the 113Cd distribution because of the shim arm depletion. One set of calculations was for the present high-enriched uranium fuel and the other for the low-enriched uranium fuel when it was in the COMP7 configuration (7 inch fuel length vs. the present 11 inch length). The depleted 113Cd distributions calculated for these cores were applied to the current design for an equilibrium low-enriched uranium core. This report details the predicted effects, if any, of shim arm depletion on the shim arm worth, the shutdown margin, power distributions and kinetics parameters.
Date: February 22, 2013
Creator: Hanson A. H.; Brown, N. & Diamond, D. J.
Object Type: Report
System: The UNT Digital Library
Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations (open access)

Entropy-Bayesian Inversion of Time-Lapse Tomographic GPR data for Monitoring Dielectric Permittivity and Soil Moisture Variations

In this study, we evaluate the possibility of monitoring soil moisture variation using tomographic ground penetrating radar travel time data through Bayesian inversion, which is integrated with entropy memory function and pilot point concepts, as well as efficient sampling approaches. It is critical to accurately estimate soil moisture content and variations in vadose zone studies. Many studies have illustrated the promise and value of GPR tomographic data for estimating soil moisture and associated changes, however, challenges still exist in the inversion of GPR tomographic data in a manner that quantifies input and predictive uncertainty, incorporates multiple data types, handles non-uniqueness and nonlinearity, and honors time-lapse tomograms collected in a series. To address these challenges, we develop a minimum relative entropy (MRE)-Bayesian based inverse modeling framework that non-subjectively defines prior probabilities, incorporates information from multiple sources, and quantifies uncertainty. The framework enables us to estimate dielectric permittivity at pilot point locations distributed within the tomogram, as well as the spatial correlation range. In the inversion framework, MRE is first used to derive prior probability density functions (pdfs) of dielectric permittivity based on prior information obtained from a straight-ray GPR inversion. The probability distributions are then sampled using a Quasi-Monte Carlo (QMC) …
Date: February 22, 2013
Creator: Hou, Zhangshuan; Terry, Neil C. & Hubbard, Susan S.
Object Type: Report
System: The UNT Digital Library
Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems (open access)

Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems

This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled “Finite Volume Based Computer Program for Ground Source Heat Pump Systems.” The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat …
Date: February 22, 2013
Creator: Menart, James A.
Object Type: Report
System: The UNT Digital Library
Final Report US Department of Energy DE-FG02-99ER45797 (open access)

Final Report US Department of Energy DE-FG02-99ER45797

This grant focused on atomistic studies of the dynamics of grain boundaries in metals performed largely using molecular dynamics simulations. One of the foci of this period was on the appropriate thermodynamics � in particular the grain boundary stiffness. We worked with a group of researchers at Carnegie Mellon University to make a comparison between grain growth simulations using our grain boundary thermodynamics data and experiments. A separate focus of the supported research looked at shear-driven grain boundary migration. The major focus of our work during this grant was a detailed consideration of the atomic mechanisms associated with grain boundary migration.
Date: February 22, 2013
Creator: Srolovitz, David J. & Haataja, Mikko
Object Type: Report
System: The UNT Digital Library
First Determination of the 8Li Valence Neutron Asymptotic Normalization Coefficient Using the 7Li(8Li,7Li)8Li Reaction (open access)

First Determination of the 8Li Valence Neutron Asymptotic Normalization Coefficient Using the 7Li(8Li,7Li)8Li Reaction

None
Date: February 22, 2013
Creator: Howell, D; Davids, B; Greene, J P; Kanungo, R; Mythili, S; Ruiz, C et al.
Object Type: Article
System: The UNT Digital Library
U.S. Offshore Wind Manufacturing and Supply Chain Development (open access)

U.S. Offshore Wind Manufacturing and Supply Chain Development

The objective of the report is to provide an assessment of the domestic supply chain and manufacturing infrastructure supporting the U.S. offshore wind market. The report provides baseline information and develops a strategy for future development of the supply chain required to support projected offshore wind deployment levels. A brief description of each of the key chapters includes: » Chapter 1: Offshore Wind Plant Costs and Anticipated Technology Advancements. Determines the cost breakdown of offshore wind plants and identifies technical trends and anticipated advancements in offshore wind manufacturing and construction. » Chapter 2: Potential Supply Chain Requirements and Opportunities. Provides an organized, analytical approach to identifying and bounding the uncertainties associated with a future U.S. offshore wind market. It projects potential component-level supply chain needs under three demand scenarios and identifies key supply chain challenges and opportunities facing the future U.S. market as well as current suppliers of the nation’s land-based wind market. » Chapter 3: Strategy for Future Development. Evaluates the gap or competitive advantage of adding manufacturing capacity in the U.S. vs. overseas, and evaluates examples of policies that have been successful . » Chapter 4: Pathways for Market Entry. Identifies technical and business pathways for market entry …
Date: February 22, 2013
Creator: Hamilton, Bruce Duncan
Object Type: Report
System: The UNT Digital Library
Measuring the alpha decay to spontaneous fission branching ratio of 252Cf with the NIFFTE TPC (open access)

Measuring the alpha decay to spontaneous fission branching ratio of 252Cf with the NIFFTE TPC

None
Date: February 22, 2013
Creator: Snyder, L & Greife, U
Object Type: Article
System: The UNT Digital Library
Finite Volume Based Computer Program for Ground Source Heat Pump System (open access)

Finite Volume Based Computer Program for Ground Source Heat Pump System

This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled ?Finite Volume Based Computer Program for Ground Source Heat Pump Systems.? The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat …
Date: February 22, 2013
Creator: Menart, James A.
Object Type: Report
System: The UNT Digital Library