CIBS Solar Cell Development Final Scientific/Technical Report (open access)

CIBS Solar Cell Development Final Scientific/Technical Report

Efforts to fabricate and study a new photovoltaic material, copper indium boron diselenide (CuInxB1-xSe2 or CIBS), were undertaken. Attempts to prepare CIBS using sputtering deposition techniques resulted in segregation of boron from the rest of elements in the material. CIBS nanocrystals were prepared from the reaction of elemental Se with CuCl, InCl3, and boric acid in solution, but the product material quickly decomposed upon heating that was required in attempts to convert the nanocrystals into a thin film. The investigation of the reasons for the lack of CIBS material stability led to new structure-property studies of closely-related photovoltaic systems as well as studies of new solar cell materials and processing methods that could enhance the development of next-generation solar technologies. A detailed compositional study of CuIn1-xAlxSe2 (CIAS, a system closely related to CIBS) revealed a non-linear correlation between crystal lattice size and the Al/(In+Al) ratios with dual-phase formation being observed. A new nanocrystal-to-thin-film processing method was developed for the preparation of CuIn1-xGaxSe2 (CIGS) thin films in which colloidal Se particles are sprayed in contact with CuIn1-xGaxS2 nanoparticles and heated in an argon atmosphere with no other Se source in the system. The process is non-vacuum and does not require toxic …
Date: September 28, 2011
Creator: Exstrom, Christopher L.; Soukup, Rodney J. & Ianno, Natale J.
System: The UNT Digital Library
REACTOR GROUT THERMAL PROPERTIES (open access)

REACTOR GROUT THERMAL PROPERTIES

Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required …
Date: January 28, 2011
Creator: Steimke, J.; Qureshi, Z.; Restivo, M. & Guerrero, H.
System: The UNT Digital Library
Inertial Confinement Fusion R&D and Nuclear Proliferation (open access)

Inertial Confinement Fusion R&D and Nuclear Proliferation

In a few months, or a few years, the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory may achieve fusion gain using 192 powerful lasers to generate x-rays that will compress and heat a small target containing isotopes of hydrogen. This event would mark a major milestone after decades of research on inertial confinement fusion (ICF). It might also mark the beginning of an accelerated global effort to harness fusion energy based on this science and technology. Unlike magnetic confinement fusion (ITER, 2011), in which hot fusion fuel is confined continuously by strong magnetic fields, inertial confinement fusion involves repetitive fusion explosions, taking advantage of some aspects of the science learned from the design and testing of hydrogen bombs. The NIF was built primarily because of the information it would provide on weapons physics, helping the United States to steward its stockpile of nuclear weapons without further underground testing. The U.S. National Academies' National Research Council is now hosting a study to assess the prospects for energy from inertial confinement fusion. While this study has a classified sub-panel on target physics, it has not been charged with examining the potential nuclear proliferation risks associated with ICF R&D. We …
Date: April 28, 2011
Creator: Goldston, Robert J.
System: The UNT Digital Library
Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Tests - 2011 (open access)

Evaluation of Cavity Collapse and Surface Crater Formation for Selected Lawrence Livermore National Laboratory Tests - 2011

This report evaluates collapse evolution for selected Lawrence Livermore National Laboratory (LLNL) underground nuclear tests at the Nevada National Security Site (NNSS, formerly called the Nevada Test Site). The work is being done at the request of National Security Technologies, LLC (NSTec) and supports the Department of Energy, National Nuclear Security Administration for the Nevada Site Office Borehole Management Program (BMP). The primary objective of this program is to close (plug) weapons program legacy boreholes that are deemed no longer useful. Safety decisions must be made before a crater area, or potential crater area, can be reentered for any work. Our statements on cavity collapse and crater formation are input into their safety decisions. The BMP is an on-going program to address hundreds of boreholes at the NTS. Each year NSTec establishes a list of holes to be addressed. They request the assistance of the Lawrence Livermore National Laboratory and Los Alamos National Laboratory Containment Programs to provide information related to the evolution of collapse history and make statements on completeness of collapse as relates to surface crater stability. These statements do not include the effects of erosion that may modify the collapse craters over time. They also do not …
Date: February 28, 2011
Creator: Pawloski, G. A.
System: The UNT Digital Library
Purdue Hydrogen Systems Laboratory (open access)

Purdue Hydrogen Systems Laboratory

The Hydrogen Systems Laboratory in a unique partnership between Purdue University's main campus in West Lafayette and the Calumet campus was established and its capabilities were enhanced towards technology demonstrators. The laboratory engaged in basic research in hydrogen production and storage and initiated engineering systems research with performance goals established as per the USDOE Hydrogen, Fuel Cells, and Infrastructure Technologies Program. In the chemical storage and recycling part of the project, we worked towards maximum recycling yield via novel chemical selection and novel recycling pathways. With the basic potential of a large hydrogen yield from AB, we used it as an example chemical but have also discovered its limitations. Further, we discovered alternate storage chemicals that appear to have advantages over AB. We improved the slurry hydrolysis approach by using advanced slurry/solution mixing techniques. We demonstrated vehicle scale aqueous and non-aqueous slurry reactors to address various engineering issues in on-board chemical hydrogen storage systems. We measured the thermal properties of raw and spent AB. Further, we conducted experiments to determine reaction mechanisms and kinetics of hydrothermolysis in hydride-rich solutions and slurries. We also developed a continuous flow reactor and a laboratory scale fuel cell power generation system. The biological hydrogen …
Date: December 28, 2011
Creator: Gore, Jay P; Kramer, Robert; Pourpoint, Timothee L; Ramachandran, P. V.; Varma, Arvind & Zheng, Yuan
System: The UNT Digital Library
Analyses by the Defense Waste Processing Facility Laboratory of Thorium Glasses from the Sludge Batch 6 Variability Study (open access)

Analyses by the Defense Waste Processing Facility Laboratory of Thorium Glasses from the Sludge Batch 6 Variability Study

The Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) is currently processing Sludge Batch 6 (SB6) with Frit 418. At times during the processing of this glass system, thorium is expected to be at concentrations in the final wasteform that make it a reportable element for the first time since startup of radioactive operations at the DWPF. The Savannah River National Laboratory (SRNL) supported the qualification of the processing of this glass system at the DWPF. A recommendation from the SRNL studies was the need for the DWPF Laboratory to establish a method to measure thorium by Inductively Coupled Plasma - Atomic Emission Spectroscopy (ICPAES). This recommendation led to the set of thorium-bearing glasses from the SB6 Variability Study (VS) being submitted to the DWPF Laboratory for chemical composition measurement. The measurements were conducted by the DWPF Laboratory using the sodium peroxide fusion preparation method routinely employed for analysis of samples from the Slurry Mix Evaporator (SME). These measurements are presented and reviewed in this report. The review indicates that the measurements provided by the DWPF Laboratory are comparable to those provided by Analytical Development's laboratory at SRNL for these same glasses. As a result, the authors of this …
Date: February 28, 2011
Creator: Edwards, T.; Click, D. & Feller, M.
System: The UNT Digital Library
SALTSTONE VAULT CLASSIFICATION SAMPLES MODULAR CAUSTIC SIDE SOLVENT EXTRACTION UNIT/ACTINIDE REMOVAL PROCESS WASTE STREAM APRIL 2011 (open access)

SALTSTONE VAULT CLASSIFICATION SAMPLES MODULAR CAUSTIC SIDE SOLVENT EXTRACTION UNIT/ACTINIDE REMOVAL PROCESS WASTE STREAM APRIL 2011

Savannah River National Laboratory (SRNL) was asked to prepare saltstone from samples of Tank 50H obtained by SRNL on April 5, 2011 (Tank 50H sampling occurred on April 4, 2011) during 2QCY11 to determine the non-hazardous nature of the grout and for additional vault classification analyses. The samples were cured and shipped to Babcock & Wilcox Technical Services Group-Radioisotope and Analytical Chemistry Laboratory (B&W TSG-RACL) to perform the Toxic Characteristic Leaching Procedure (TCLP) and subsequent extract analysis on saltstone samples for the analytes required for the quarterly analysis saltstone sample. In addition to the eight toxic metals - arsenic, barium, cadmium, chromium, mercury, lead, selenium and silver - analytes included the underlying hazardous constituents (UHC) antimony, beryllium, nickel, and thallium which could not be eliminated from analysis by process knowledge. Additional inorganic species determined by B&W TSG-RACL include aluminum, boron, chloride, cobalt, copper, fluoride, iron, lithium, manganese, molybdenum, nitrate/nitrite as Nitrogen, strontium, sulfate, uranium, and zinc and the following radionuclides: gross alpha, gross beta/gamma, 3H, 60Co, 90Sr, 99Tc, 106Ru, 106Rh, 125Sb, 137Cs, 137mBa, 154Eu, 238Pu, 239/240Pu, 241Pu, 241Am, 242Cm, and 243/244Cm. B&W TSG-RACL provided subsamples to GEL Laboratories, LLC for analysis for the VOCs benzene, toluene, and 1-butanol. GEL also …
Date: September 28, 2011
Creator: Eibling, R.
System: The UNT Digital Library
ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT #050411 (open access)

ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT #050411

Harrell Industries is under contract with Savannah River Remediation to provide Monosodium titanate (MST) for use in the Actinide Removal Process (ARP). A 500-mL qualification sample for Lot 050411 was sent to the Savannah River National Laboratory (SRNL) to confirm the material meets the requirements specified in the purchase specification. The vendor is also obligated to send verification samples from {approx}10% or more of the pails of MST product for each lot (distributed roughly evenly through the entire lot of pails). For the verification of this lot, Harrell Industries sent 12 samples, one each from pails No.1, 10, 20, 30, 40, 60, 70, 80, 90, 100, 110, and 120 of 120 total pails. MST for use in the Actinide Removal Process (ARP) must be qualified and verified in advance. A single qualification sample for each batch of material is sent to SRNL for analysis, as well as a statistical sampling of verification samples. The Harrell Industries Lot 050411 qualification and 12 verification samples met all the requirements in the specification indicating the material is acceptable for use in the process.
Date: June 28, 2011
Creator: Taylor-Pashow, K.
System: The UNT Digital Library
Rapid Exploitation and Analysis of Documents (open access)

Rapid Exploitation and Analysis of Documents

Analysts are overwhelmed with information. They have large archives of historical data, both structured and unstructured, and continuous streams of relevant messages and documents that they need to match to current tasks, digest, and incorporate into their analysis. The purpose of the READ project is to develop technologies to make it easier to catalog, classify, and locate relevant information. We approached this task from multiple angles. First, we tackle the issue of processing large quantities of information in reasonable time. Second, we provide mechanisms that allow users to customize their queries based on latent topics exposed from corpus statistics. Third, we assist users in organizing query results, adding localized expert structure over results. Forth, we use word sense disambiguation techniques to increase the precision of matching user generated keyword lists with terms and concepts in the corpus. Fifth, we enhance co-occurrence statistics with latent topic attribution, to aid entity relationship discovery. Finally we quantitatively analyze the quality of three popular latent modeling techniques to examine under which circumstances each is useful.
Date: November 28, 2011
Creator: Buttler, D J; Andrzejewski, D; Stevens, K D; Anastasiu, D & Gao, B
System: The UNT Digital Library
PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise (open access)

PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise

This document reports the results of the Hanford personnel nuclear accident dosimeter (PNAD) and fixed nuclear accident dosimeter (FNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on September 20-23, 2010. Pacific Northwest National Laboratory (PNNL) participated in a criticality accident dosimeter intercomparison exercise at the Commissariat a Energie Atomique (CEA) Valduc Center near Dijon, France on September 20-23, 2010. The intercomparison exercise was funded by the U.S. Department of Energy, Nuclear Criticality Safety Program, with Lawrence Livermore National Laboratory as the lead Laboratory. PNNL was one of six invited DOE Laboratory participants. The other participating Laboratories were: Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 National Security Complex at Oak Ridge, and Sandia National Laboratory (SNL). The goals of PNNL's participation in the intercomparison exercise were to test and validate the procedures and algorithm currently used for the Hanford personnel nuclear accident dosimeters (PNADs) on the metallic reactor, CALIBAN, to test exposures to PNADs from the side and from behind a phantom, and to test PNADs that were taken from a historical batch of Hanford PNADs that had varying degrees of degradation of the bare indium foil. …
Date: October 28, 2011
Creator: Hill, Robin L. & Conrady, Matthew M.
System: The UNT Digital Library
Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project (open access)

Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

The U.S. Department of Energy is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr to a much larger figure nationally. Most of the energy savings in this application is attributable to the instant-restrike capability of LED products and to their high tolerance for frequent on/off switching, used here to separately control either end of the tunnel during daytime hours. Some LED luminaires rival or outperform their high-intensity discharge (HID) counterparts in terms of efficacy, but options are limited, and smaller lumen packages preclude true one-for-one equivalence. However, LED products continue to improve in efficacy and affordability at a rate unmatched by other light source technologies; the estimated simple payback period of eight years (excluding installation costs and maintenance savings) can be expected to improve with time. The proposed revisions to the existing high-pressure sodium (HPS) lighting system would require slightly increased controls complexity and significantly increased luminaire types and quantities. In exchange, substantial annual savings (from reduced …
Date: June 28, 2011
Creator: Tuenge, Jason R.
System: The UNT Digital Library
Computational Efficient Upscaling Methodology for Predicting Thermal Conductivity of Nuclear Waste forms (open access)

Computational Efficient Upscaling Methodology for Predicting Thermal Conductivity of Nuclear Waste forms

This study evaluated different upscaling methods to predict thermal conductivity in loaded nuclear waste form, a heterogeneous material system. The efficiency and accuracy of these methods were compared. Thermal conductivity in loaded nuclear waste form is an important property specific to scientific researchers, in waste form Integrated performance and safety code (IPSC). The effective thermal conductivity obtained from microstructure information and local thermal conductivity of different components is critical in predicting the life and performance of waste form during storage. How the heat generated during storage is directly related to thermal conductivity, which in turn determining the mechanical deformation behavior, corrosion resistance and aging performance. Several methods, including the Taylor model, Sachs model, self-consistent model, and statistical upscaling models were developed and implemented. Due to the absence of experimental data, prediction results from finite element method (FEM) were used as reference to determine the accuracy of different upscaling models. Micrographs from different loading of nuclear waste were used in the prediction of thermal conductivity. Prediction results demonstrated that in term of efficiency, boundary models (Taylor and Sachs model) are better than self consistent model, statistical upscaling method and FEM. Balancing the computation resource and accuracy, statistical upscaling is a computational …
Date: September 28, 2011
Creator: Li, Dongsheng; Sun, Xin & Khaleel, Mohammad A.
System: The UNT Digital Library
Analysis of IECC (2003, 2006, 2009) and ASHRAE 90.1-2007 Commercial Energy Code Requirements for Mesa, AZ. (open access)

Analysis of IECC (2003, 2006, 2009) and ASHRAE 90.1-2007 Commercial Energy Code Requirements for Mesa, AZ.

This report summarizes code requirements and energy savings of commercial buildings in Climate Zone 2B built to the 2009 IECC and ASHRAE Standard 90.1-2007 when compared to the 2003 IECC and the 2006 IECC. In general, the 2009 IECC and ASHRAE Standard 90.1-2007 have higher insulation requirements for exterior walls, roof, and windows and have higher efficiency requirements for HVAC equipment. HVAC equipment efficiency requirements are governed by National Appliance Conversion Act of 1987 (NAECA), and are applicable irrespective of the IECC version adopted. The energy analysis results show that commercial buildings meeting the 2009 IECC requirements save 4.4% to 9.5% site energy and 4.1% to 9.9% energy cost when compared to the 2006 IECC; and save 10.6% to 29.4% site energy and 10.3% to 29.3% energy cost when compared to the 2003 IECC. Similar analysis comparing ASHRAE Standard 90.1-2007 requirements to the 2006 IECC shows that the energy savings are in the 4.0% to 10.7% for multi-family and retail buildings, but less than 2% for office buildings. Further comparison of ASHRAE Standard 90.1-2007 requirements to the 2003 IECC show site energy savings in the range of 7.7% to 30.6% and energy cost savings range from 7.9% to 30.3%. Both …
Date: February 28, 2011
Creator: Huang, Yunzhi & Gowri, Krishnan
System: The UNT Digital Library
ORKA: Measurement of the $K^ \to \pi^+ \nu \bar{\nu}$ decay at Fermilab (open access)

ORKA: Measurement of the $K^ \to \pi^+ \nu \bar{\nu}$ decay at Fermilab

A high precision measurement of the ultra-rare K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} decay at Fermilab would be one of the most incisive probes of quark flavor physics this decade. Its dramatic reach for uncovering new physics is due to several important factors: (1) The branching ratio is sensitive to most new physics models which extend the Standard Model to solve its considerable problems. (2) The Standard Model predictions for the K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} and K{sub L}{sup 0} {yields} {pi}{sup 0} {nu}{bar {nu}} branching fractions are broadly recognized to be theoretically robust at the 5-10% level. Only a precious few accessible loop-dominated quark processes can be predicted with this level of certainty. (3) The K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} branching fraction is highly suppressed in the Standard Model to the level < 10{sup -10} (<1 part in 10 billion). This suppression allows physics beyond the Standard Model to contribute dramatically to the branching fraction with enhancements of up to factors of 5 above the Standard Model level. (4) The certainty with which the Standard Model contribution to K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} can be predicted will permit a 5{sigma} discovery potential …
Date: November 28, 2011
Creator: Comfort, Joseph; U., /Arizona State; Bryman, Douglas; Doria, Luca; Numao, Toshio; Sher, Aleksey et al.
System: The UNT Digital Library
THERMODYNAMIC AND KINETIC MODELING OF ADVANCED NUCLEAR FUELS - FINAL LDRD-ER REPORT (open access)

THERMODYNAMIC AND KINETIC MODELING OF ADVANCED NUCLEAR FUELS - FINAL LDRD-ER REPORT

This project enhanced our theoretical capabilities geared towards establishing the basic science of a high-throughput protocol for the development of advanced nuclear fuel that should couple modern computational materials modeling and simulation tools, fabrication and characterization capabilities, and targeted high throughput performance testing experiments. The successful conclusion of this ER project allowed us to upgrade state-of-the-art modeling codes, and apply these modeling tools to ab initio energetics and thermodynamic assessments of phase diagrams of various mixtures of actinide alloys, propose a tool for optimizing composition of complex alloys for specific properties, predict diffusion behavior in diffusion couples made of actinide and transition metals, include one new equation in the LLNL phase-field AMPE code, and predict microstructure evolution during alloy coring. In FY11, despite limited funding, the team also initiated an experimental activity, with collaboration from Texas A&M University by preparing samples of nuclear fuels in bulk forms and for diffusion couple studies and metallic matrices, and performing preliminary characterization.
Date: November 28, 2011
Creator: Turchi, P
System: The UNT Digital Library
Final Technical Report: Results of Phase 1 (open access)

Final Technical Report: Results of Phase 1

Arizona Public Service Company (APS) expects that by 2027, renewable energy will account for 6,590 GWh in energy consumption by its customers. While much of this future energy will come from large centrally-located power plants, distributed renewable energy, sited at the point of end-use will also play an important role in meeting the needs of APS customers and is expected to provide 1,734 GWh. With increasing penetration of residential and commercial photovoltaic (PV) systems at the point of end-use, PV power generation not only offsets the load, but could also cause significant shifts in power flow patterns through the distribution system, and could possibly cause reversal of flow through some branches of a distribution circuit. Significant changes to power flow introduced into existing distribution systems due to the increased amount of PV systems may cause operational issues, including over-voltage on the distribution feeder (loss of voltage regulation) and incorrect operation of control equipment, which may lead to an increase in the number of operations and related equipment wear that could affect equipment reliability and customer power quality. Additionally, connecting generation resources to a distribution feeder can introduce additional sources of short-circuit current to the distribution system. This could potentially result …
Date: September 28, 2011
Creator: Narang, David, J.; Hambrick, Joshua; Srinivasan, Devarajan; Ayyannar, Raja; O'Brien, Kathleen; Bebic, Jovan et al.
System: The UNT Digital Library
Laboratory Studies on Surface Sampling of Bacillus anthracis Contamination: Summary, Gaps, and Recommendations (open access)

Laboratory Studies on Surface Sampling of Bacillus anthracis Contamination: Summary, Gaps, and Recommendations

This report summarizes previous laboratory studies to characterize the performance of methods for collecting, storing/transporting, processing, and analyzing samples from surfaces contaminated by Bacillus anthracis or related surrogates. The focus is on plate culture and count estimates of surface contamination for swab, wipe, and vacuum samples of porous and nonporous surfaces. Summaries of the previous studies and their results were assessed to identify gaps in information needed as inputs to calculate key parameters critical to risk management in biothreat incidents. One key parameter is the number of samples needed to make characterization or clearance decisions with specified statistical confidence. Other key parameters include the ability to calculate, following contamination incidents, the (1) estimates of Bacillus anthracis contamination, as well as the bias and uncertainties in the estimates, and (2) confidence in characterization and clearance decisions for contaminated or decontaminated buildings. Gaps in knowledge and understanding identified during the summary of the studies are discussed and recommendations are given for future studies.
Date: November 28, 2011
Creator: Piepel, Gregory F.; Amidan, Brett G. & Hu, Rebecca
System: The UNT Digital Library
Coal/Biomass Gasification at the Colorado School of Mines (open access)

Coal/Biomass Gasification at the Colorado School of Mines

This program was a 2.5 year effort focused on technologies that support coal and biomass gasification. Two primary tasks were included in the effort: 1) Coal/Biomass gasification and system optimization and 2) development of high temperature microchannel ceramic heat exchangers.
Date: February 28, 2011
Creator: Parker, Terry; Braun, Robert; Dreyer, Chris; Dean, Anthony; Eberhart, Mark; Kee, Robert et al.
System: The UNT Digital Library
Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing (open access)

Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.
Date: January 28, 2011
Creator: Xu, Dr. X. Geroge
System: The UNT Digital Library
Effect of Gaseous Impurities on Long-Term Thermal Cycling and Aging Properties of Complex Hydrides for Hydrogen Storage (open access)

Effect of Gaseous Impurities on Long-Term Thermal Cycling and Aging Properties of Complex Hydrides for Hydrogen Storage

This program was dedicated to understanding the effect of impurities on Long-Term Thermal Cycling and aging properties of Complex Hydrides for Hydrogen Storage. At the start of the program we found reversibility between Li2NH+LiH  LiH+LiNH2 (yielding ~5.8 wt.%H capacity). Then we tested the effect of impurity in H2 gas by pressure cycling at 255oC; first with industrial gas containing ppm levels of O2 and H2O as major impurities. Both these impurities had a significant impact on the reversibility and decreased the capacity by 2.65 wt.%H. Further increase in number of cycles from 500 to 1100 showed only a 0.2 wt%H more weight loss, showing some capacity is still maintained after a significant number of cycles. The loss of capacity is attributed to the formation of ~55 wt% LiH and ~30% Li2O, as major contaminant phases, along with the hydride Li2NH phase; suggesting loss of nitrogen during cycling. The effect of 100 ppm H2O in H2 also showed a decrease of ~2.5 wt.%H (after 560 cycles), and 100ppm O2 in H2; a loss of ~4.1 wt.%. Methane impurity (100 ppm, 100cycles), showed a very small capacity loss of 0.9 wt.%H under similar conditions. However, when Li3N was pressure cycled with …
Date: March 28, 2011
Creator: Chandra, Dhanesh; Lamb, Joshua; Chien, Wen-Ming; Talekar, Anjali & Pal, Narendra
System: The UNT Digital Library
Interfacial Area Transport and Regime Transition in Combinatorial Channels (open access)

Interfacial Area Transport and Regime Transition in Combinatorial Channels

. This study investigates the geometric effects of 90-degree vertical elbows and flow configurations in two-phase flow. The study shows that the elbows make a significant effect on the transport characteristics of two-phase flow, which includes the changes in interfacial structures, bubble interaction mechanisms and flow regime transition. The effect of the elbows is characterized for global and local two-phase flow parameters. The global two-phase flow parameters include two-phase pressure, interfacial structures and flow regime transition. In order to characterize the frictional pressure drop and minor loss across the vertical elbows, pressure measurements are obtained across the test section over a wide range of flow conditions in both single-phase and two-phase flow conditions. A two-phase pressure drop correlation analogous to Lockhart-Martinelli correlation is proposed to predict the minor loss across the elbows. A high speed camera is employed to perform extensive flow visualization studies across the elbows in vertical upward, horizontal and vertical downward sections and modified flow regime maps are proposed. It is found that modified flow regime maps immediately downstream of the vertical upward elbow deviate significantly from the conventional flow regime map. A qualitative assessment of the counter-current flow limitation characteristics specific to the current experimental facility …
Date: January 28, 2011
Creator: Kim, Seugjin
System: The UNT Digital Library
Power Minimization techniques for Networked Data Centers. (open access)

Power Minimization techniques for Networked Data Centers.

Our objective is to develop a mathematical model to optimize energy consumption at multiple levels in networked data centers, and develop abstract algorithms to optimize not only individual servers, but also coordinate the energy consumption of clusters of servers within a data center and across geographically distributed data centers to minimize the overall energy cost and consumption of brown energy of an enterprise. In this project, we have formulated a variety of optimization models, some stochastic others deterministic, and have obtained a variety of qualitative results on the structural properties, robustness, and scalability of the optimal policies. We have also systematically derived from these models decentralized algorithms to optimize energy efficiency, analyzed their optimality and stability properties. Finally, we have conducted preliminary numerical simulations to illustrate the behavior of these algorithms. We draw the following conclusion. First, there is a substantial opportunity to minimize both the amount and the cost of electricity consumption in a network of datacenters, by exploiting the fact that traffic load, electricity cost, and availability of renewable generation fluctuate over time and across geographical locations. Judiciously matching these stochastic processes can optimize the tradeoff between brown energy consumption, electricity cost, and response time. Second, given the …
Date: September 28, 2011
Creator: Low, Steven & Tang, Kevin
System: The UNT Digital Library
Completion Report for Wells ER-20-8 and ER-20-8#2 Corrective Action Units 101 and 102: Central and Western Pahute Mesa (open access)

Completion Report for Wells ER-20-8 and ER-20-8#2 Corrective Action Units 101 and 102: Central and Western Pahute Mesa

Wells ER-20-8 and ER-20-8#2 were drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Project at the Nevada National Security Site (formerly Nevada Test Site), Nye County, Nevada. The holes were drilled in July and August 2009, as part of the Pahute Mesa Phase II drilling program. The primary purpose of these wells was to provide detailed hydrogeologic information in the Tertiary volcanic section that will help address uncertainties within the Pahute Mesa–Oasis Valley hydrostratigraphic framework model. They may also be used as long-term monitoring wells.
Date: February 28, 2011
Creator: National Security Technologies, LLC
System: The UNT Digital Library
Collaborative Research: The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change (open access)

Collaborative Research: The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change

Uncertainties in representing the atmospheric water cycle are major obstacles to an accurate prediction of future climate. This project focused on addressing some of these uncertainties by implementing new physics for convection and radiation into the NCAR climate model. To better understand and eventually better represent these processes, we modified CAM3.5 to use the convection and cloud schemes developed by the Massachusetts Institute of Technology (MIT) and the RRTMG rapid radiation code for global models developed by Atmospheric and Environmental Research, Inc. (AER). The impact of the new physics on the CAM3.5 simulation of convection on diurnal and intra-seasonal scales, intra-seasonal oscillations and the distribution of water vapor has been investigated. The effect of the MIT and AER physics also has been tested in the Weather Research and Forecasting (WRF) regional forecast model. It has been found that the application of the AER radiation and MIT convection produces significant improvements in the modeled diurnal cycle of convection, especially over land, in the NCAR climate model. However, both the standard CAM3.5 (hereinafter STD) and the modified CAM3.5 with the new physics (hereinafter MOD) are still unable to capture the proper spectrum and propagating characteristics of the intra-seasonal oscillations (ISOs). The new …
Date: June 28, 2011
Creator: Emanuel, Dr. Kerry & Iacono, Michael J.
System: The UNT Digital Library