States

General Services Administration Federal Facilities Affected by Hurricane Katrina (open access)

General Services Administration Federal Facilities Affected by Hurricane Katrina

This report mainly focuses on the General Services Administration Federal Facilities Affected by Hurricane Katrina where Katrina struck the Golf of coast on August 2005 causing wide spread flooding and significant infrastructure damage to various federal facilities.
Date: May 9, 2006
Creator: Smith, Stephanie
Object Type: Report
System: The UNT Digital Library
Non-Equilibrium Nanoscale Self-Organization (open access)

Non-Equilibrium Nanoscale Self-Organization

Self-organized one- and two-dimensional arrays of nanoscale surface features ("ripples" and "dots") sometimes form spontaneously on initially flat surfaces eroded by a directed ion beam in a process called "sputter patterning". Experiments on this sputter patterning process with focused and unfocused ion beams, combined with theoretical advances, have been responsible for a number of scientific advances. Particularly noteworthy are (i) the discovery of propagative, rather than dissipative, behavior under some ion erosion conditions, permitting a pattern to be fabricated at a large length scale and propagated over large distances while maintaining, or even sharpening, the sharpest features; (ii) the first demonstration of guided self-organization of sputter patterns, along with the observation that defect density is minimized when the spacing between boundaries is near an integer times the natural spatial period; and (iii) the discovery of metastability of smooth surfaces, which contradicts the nearly universally accepted linear stability theory that predicts that any surface is linearly unstable to sinusoidal perturbations of some wave vector.
Date: March 9, 2006
Creator: Aziz, Michael J
Object Type: Report
System: The UNT Digital Library
A STRUCTURAL INTEGRITY EVALUATION OF THE TANK FARM WASTE TRANSFER SYSTEM (open access)

A STRUCTURAL INTEGRITY EVALUATION OF THE TANK FARM WASTE TRANSFER SYSTEM

Radioactive supernate, salt, and/or sludge wastes (i.e., high level wastes) are confined in 49 underground storage tanks at the Savannah River Site (SRS). The waste is transported between tanks within and between the F and H area tank farms and other facilities on site via underground and a limited number of aboveground transfer lines. The Department of Energy - Savannah River Operations Office (DOE-SR) performed a comprehensive assessment of the structural integrity program for the Tank Farm waste transfer system at the SRS. This document addresses the following issues raised during the DOE assessment: (1) Inspections of failed or replaced transfer lines indicated that the wall thickness of some core and jacket piping is less than nominal; (2) No corrosion allowance is utilized in the transfer line structural qualification calculations. No basis for neglecting corrosion was provided in the calculations; (3) Wall loss due to erosion is not addressed in the transfer line structural qualification calculations; and (4) No basis is provided for neglecting intergranular stress corrosion cracking in the transfer line structural qualification calculations. The common theme in most of these issues is the need to assess the potential for occurrence of material degradation of the transfer line piping. …
Date: March 9, 2006
Creator: Wiersma, B.
Object Type: Report
System: The UNT Digital Library
Three Dimensional Holographic Archival Memory (open access)

Three Dimensional Holographic Archival Memory

To address the DOE need for the storage and handling of terabyte of nuclear physics data, Physical Optics Corporation (POC) developed a new multi-terabit, 90° recording geometry 3D holographic archival optical memory storage and search system. In contrast to state-of-the-art memory approaches, 3DHAM handles the data through highly parallel optical processing in conjunction with highly redundant hologram multiplexing. The 3DHAM system advantages also stem from its unique 3D volume-recording medium, which theoretically has a significantly greater data density than diskbased systems.
Date: November 9, 2006
Creator: Gibbard, Bruce
Object Type: Report
System: The UNT Digital Library
Evolutionary Genomics of Life in (and from) the Sea (open access)

Evolutionary Genomics of Life in (and from) the Sea

High throughput genome sequencing centers that were originally built for the Human Genome Project (Lander et al., 2001; Venter et al., 2001) have now become an engine for comparative genomics. The six largest centers alone are now producing over 150 billion nucleotides per year, more than 50 times the amount of DNA in the human genome, and nearly all of this is directed at projects that promise great insights into the pattern and processes of evolution. Unfortunately, this data is being produced at a pace far exceeding the capacity of the scientific community to provide insightful analysis, and few scientists with training and experience in evolutionary biology have played prominent roles to date. One of the consequences is that poor quality analyses are typical; for example, orthology among genes is generally determined by simple measures of sequence similarity, when this has been discredited by molecular evolutionary biologists decades ago. Here we discuss the how genomes are chosen for sequencing and how the scientific community can have input. We describe the PhIGs database and web tools (Dehal and Boore 2005a; http://PhIGs.org), which provide phylogenetic analysis of all gene families for all completely sequenced genomes and the associated 'Synteny Viewer', which allows …
Date: January 9, 2006
Creator: Boore, Jeffrey L.; Dehal, Paramvir & Fuerstenberg, Susan I.
Object Type: Report
System: The UNT Digital Library
Vogtle Electric Generating Plant ETE Analysis Review (open access)

Vogtle Electric Generating Plant ETE Analysis Review

Under contract with the Nuclear Regulatory Commission (NRC), staff from Pacific Northwest National Laboratory (PNNL) and Sandia National Laboratory (SNL)-Albuquerque reviewed the evacuation time estimate (ETE) analysis dated April 2006 prepared by IEM for the Vogtle Electric Generating Plant (VEGP). The ETE analysis was reviewed for consistency with federal regulations using the NRC guidelines in Review Standard (RS)-002, Supplement 2 and Appendix 4 to NUREG-0654, and NUREG/CR-4831. Additional sources of information referenced in the analysis and used in the review included NUREG/CR-6863 and NUREG/CR-6864. The PNNL report includes general comments, data needs or clarifications, and requests for additional information (RAI) resulting from review of the ETE analysis.
Date: December 9, 2006
Creator: Diediker, Nona H. & Jones, Joe A.
Object Type: Report
System: The UNT Digital Library
STOMP Subsurface Transport Over Multiple Phases, Version 4.0, User’s Guide (open access)

STOMP Subsurface Transport Over Multiple Phases, Version 4.0, User’s Guide

This guide describes the general use, input file formatting, compilation and execution of the STOMP (Subsurface Transport Over Multiple Phases) simulator, a scientific tool for analyzing single and multiple phase subsurface flow and transport. A description of the simulator’s governing equations, constitutive functions and numerical solution algorithms are provided in a companion theory guide. In writing these guides for the STOMP simulator, the authors have assumed that the reader comprehends concepts and theories associated with multiple-phase hydrology, heat transfer, thermodynamics, radioactive chain decay, and relative permeability-saturation-capillary pressure constitutive relations. The authors further assume that the reader is familiar with the computing environment on which they plan to compile and execute the STOMP simulator. Source codes for the sequential versions of the simulator are available in pure FORTRAN 77 or mixed FORTRAN 77/90 forms. The pure FORTRAN 77 source code form requires a parameters file to define the memory requirements for the array elements. The mixed FORTRAN 77/90 form of the source code uses dynamic memory allocation to define memory requirements, based on a FORTRAN 90 preprocessor STEP, that reads the input files. The simulator utilizes a variable source code configuration, which allows the execution memory and speed to be tailored …
Date: June 9, 2006
Creator: White, Mark D. & Oostrom, Martinus
Object Type: Report
System: The UNT Digital Library
Exemptions from Environmental Law for the Department of Defense: An Overview of Congressional Action (open access)

Exemptions from Environmental Law for the Department of Defense: An Overview of Congressional Action

This report discusses the difficulty of assessing the impact of environmental requirements on military readiness, broader exemptions for military activities that Congress has enacted, and DOD's request for additional exemptions.
Date: January 9, 2006
Creator: Bearden, David M.
Object Type: Report
System: The UNT Digital Library
ParaDiS on Blue Gene/L: stepping up to the challenge (open access)

ParaDiS on Blue Gene/L: stepping up to the challenge

This paper reports on the efforts to enable fully scalable simulations of Dislocation Line Dynamics (DLD) for direct calculations of strength of crystalline materials. DLD simulations are challenging and do not lend themselves naturally to parallel computing. Through a combinations of novel physical approaches, mathematical algorithms and computational science developments, a new DLD code ParaDiS is shown to take meaningful advantage of BG/L and, by doing so, to enable discovery class science by computation.
Date: June 9, 2006
Creator: Hommes, Gregg; Arsenlis, Athanasios; Bulatov, Vasily; Cai, Wei; Cook, Richard; Hiratani, Masato et al.
Object Type: Article
System: The UNT Digital Library
Examination of Corrosion Products and the Alloy Surface After Crevice Corrosion of a Ni-Cr-Mo- Alloy (open access)

Examination of Corrosion Products and the Alloy Surface After Crevice Corrosion of a Ni-Cr-Mo- Alloy

The objective of this study is to investigate the composition of corrosion products and the metal surface within a crevice after localized corrosion. The analysis provides insight into the propagation, stifling and arrest processes for crevice corrosion and is part of a program to analyze the evolution of localized corrosion damage over long periods of time, i.e. 10,000 years and longer. The approach is to force the initiation of crevice corrosion by applying anodic polarization to a multiple crevice assembly (MCA). Results are reported here for alloy C-22, a Ni-Cr-Mo alloy, exposed to a high temperature, concentrated chloride solution. Controlled crevice corrosion tests were performed on C-22 under highly aggressive, accelerated condition, i.e. 4M NaCl, 100 C and anodic polarization to -0.15V-SCE. The crevice contacts were by either a polymer tape (PTFE) compressed by a ceramic former or by a polymer (PTFE) crevice former. Figure 1 shows the polarization current during a crevice corrosion test. After an incubation period, several initiation-stifle-arrest events were indicated. The low current at the end of the test indicated that the metal surface had repassivated.
Date: June 9, 2006
Creator: Shan, X. & Payer, J.H.
Object Type: Report
System: The UNT Digital Library
Band gap bowing and electron localization of (GaxIn1-x)N (open access)

Band gap bowing and electron localization of (GaxIn1-x)N

The band gap bowing and the electron localization ofGaxIn1-xN are calculated using both the local density approximation (LDA)and screened-exchange local density functional (sX-LDA) methods. Thecalculated sX-LDA band gaps are in good agreement with the experimentallyobserved values, with errors of -0.26 and 0.09 eV for bulk GaN and InN,respectively. The LDA band gap errors are 1.33 and 0.81 eV for GaN andInN, in order. In contrast to the gap itself, the band gap bowingparameter is found to be very similar in sX-LDA and LDA. We identify thelocalization of hole states in GaxIn1-xN alloys along In-N-In chains. Thepredicted localizationis stronger in sX-LDA.
Date: May 9, 2006
Creator: Lee, Byounghak & Wang, Lin-Wang
Object Type: Article
System: The UNT Digital Library
Dissimilar behavior of technetium and rhenium in borosilicatewaste glass as determined by X-ray absorption spectroscopy (open access)

Dissimilar behavior of technetium and rhenium in borosilicatewaste glass as determined by X-ray absorption spectroscopy

Technetium-99 is an abundant, long-lived (t1/2 = 213,000 yr)fission product that creates challenges for the safe, long-term disposalof nuclear waste. While 99Tc receives attention largely due to its highenvironmental mobility, it also causes problems during its incorporationinto nuclear waste glass due to the volatility of Tc(VII) compounds. Thisvolatility decreases the amount of 99Tc stabilized in the waste glass andcauses contamination of the waste glass melter and off-gas system. Theapproach to decrease the volatility of 99Tc that has received the mostattention is reduction of the volatile Tc(VII) species to less volatileTc(IV) species in the glass melt. On engineering scale experiments,rhenium is often used as a non-radioactive surrogate for 99Tc to avoidthe radioactive contamination problems caused by volatile 99Tc compounds.However, Re(VII) is more stable towards reduction than Tc(VII), so morereducing conditions would be required in the glass melt to produceRe(IV). To better understand the redox behavior of Tc and Re in nuclearwaste glass, a series of glasses were prepared under different redoxconditions. The speciation of Tc and Re in the resulting glasses wasdetermined by X-ray absorption fine structure spectroscopy. Surprisingly,Re and Tc do not behave similarly in the glass melt. Although Tc(0),Tc(IV), and Tc(VII) were observed in these samples, only Re(0) andRe(VII) …
Date: November 9, 2006
Creator: Lukens, Wayne W.; McKeown, David A.; Buechele, Andrew C.; Muller,Isabelle S.; Shuh, David K. & Pegg, Ian L.
Object Type: Article
System: The UNT Digital Library
Hybrid Solar Cells with Prescribed Nanoscale Morphologies Based onHyperbranched Semiconductor Nanocrystals (open access)

Hybrid Solar Cells with Prescribed Nanoscale Morphologies Based onHyperbranched Semiconductor Nanocrystals

In recent years, the search to develop large-area solar cells at low cost has led to research on photovoltaic (PV) systems based on nanocomposites containing conjugated polymers. These composite films can be synthesized and processed at lower costs and with greater versatility than the solid state inorganic semiconductors that comprise today's solar cells. However, the best nanocomposite solar cells are based on a complex architecture, consisting of a fine blend of interpenetrating and percolating donor and acceptor materials. Cell performance is strongly dependent on blend morphology, and solution-based fabrication techniques often result in uncontrolled and irreproducible blends, whose composite morphologies are difficult to characterize accurately. Here we incorporate 3-dimensional hyper-branched colloidal semiconductor nanocrystals in solution-processed hybrid organic-inorganic solar cells, yielding reproducible and controlled nanoscale morphology.
Date: September 9, 2006
Creator: Gur, Ilan; Fromer, Neil A.; Chen, Chih-Ping; Kanaras, AntoniosG. & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry (open access)

High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing the useful analytical signal [1]. The ICP both atomizes and ionizes the sample. Polyatomic ions form through ion-molecule interactions either in the ICP or during ion extraction [l]. Common polyatomic ions that inhibit analysis include metal oxides (MO{sup +}), adducts with argon, the gas most commonly used to make up the plasma, and hydride species. While high resolution devices can separate many analytes from common interferences, this is done at great cost in ion transmission efficiency--a loss of 99% when using high versus low resolution on the same instrument [2]. Simple quadrupole devices, which make up the bulk of ICP-MS instruments in existence, do not present this option. Therefore, if the source of polyatomic interferences can be determined and …
Date: August 9, 2006
Creator: Ferguson, Jill Wisnewski
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Ground State Quarkonium Spectral Functions Above Deconfinement. (open access)

Ground State Quarkonium Spectral Functions Above Deconfinement.

We discuss the temperature-dependence of S-wave quarkonium spectral functions in a nonrelativistic Green's function approach and compare these to lattice QCD results.
Date: June 9, 2006
Creator: Mocsy, A.; Petreczky, P. & Casalderrey-Solana, J.
Object Type: Article
System: The UNT Digital Library
Designing of Metallic Photonic Structures and Applications (open access)

Designing of Metallic Photonic Structures and Applications

In this thesis our main interest has been to investigate metallic photonic crystal and its applications. We explained how to solve a periodic photonic structure with transfer matrix method and when and how to use modal expansion method. Two different coating methods were introduced, modifying a photonic structure's intrinsic optical properties and rigorous calculation results are presented. Two applications of metallic photonic structures are introduced. For thermal emitter, we showed how to design and find optimal structure. For conversion efficiency increasing filter, we calculated its efficiency and the way to design it. We presented the relation between emitting light spectrum and absorption and showed the material and structural dependency of the absorption spectrum. By choosing a proper base material and structural parameters, we can design a selective emitter at a certain region we are interested in. We have developed a theoretical model to analyze a blackbody filament enclosed by a metallic mesh which can increase the efficiency of converting a blackbody radiation to visible light. With this model we found that a square lattice metallic mesh enclosing a filament might increase the efficiency of incandescent lighting sources. Filling fraction and thickness dependency were examined and presented. Combining these two parameters …
Date: August 9, 2006
Creator: Kim, Yong-Sung
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Overview of Theory and Simulations in the Heavy Ion Fusion ScienceVirtual National Laboratory (open access)

Overview of Theory and Simulations in the Heavy Ion Fusion ScienceVirtual National Laboratory

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) is a collaboration of Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, and Princeton Plasma Physics Laboratory. These laboratories, in cooperation with researchers at other institutions, are carrying out a coordinated effort to apply intense ion beams as drivers for studies of the physics of matter at extreme conditions, and ultimately for inertial fusion energy. Progress on this endeavor depends upon coordinated application of experiments, theory, and simulations. This paper describes the state of the art, with an emphasis on the coordination of modeling and experiment; developments in the simulation tools, and in the methods that underly them, are also treated.
Date: July 9, 2006
Creator: Friedman, Alex
Object Type: Article
System: The UNT Digital Library
Fusion of X-Ray and Ultrasound Images for As-Built Modeling (open access)

Fusion of X-Ray and Ultrasound Images for As-Built Modeling

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Date: November 9, 2006
Creator: Clark, G A & Jackson, J A
Object Type: Article
System: The UNT Digital Library
Improved Statistics for Determining the Patterson Symmetry fromUnmerged Diffraction Intensities (open access)

Improved Statistics for Determining the Patterson Symmetry fromUnmerged Diffraction Intensities

We examine procedures for detecting the point-group symmetryof macromolecular datasets and propose enhancements. To validate apoint-group, it is sufficient to compare pairs of Bragg reflections thatare related by each of the group's component symmetry operators.Correlation is commonly expressed in the form of a single statisticalquantity (such as Rmerge) that incorporates information from all of theobserved reflections. However, the usual practice of weighting all pairsof symmetry-related intensities equally can obscure the fact that thevarious symmetry operators of the point-group contribute differingfractions of the total set. In some cases where particular symmetryelements are significantly under-represented, statistics calculatedglobally over all observations do not permit conclusions about thepoint-group and Patterson symmetry. The problem can be avoided byrepartitioning the data in a way that explicitly takes note of individualoperators. The new analysis methods, incorporated into the programLABELIT (cci.lbl.gov/labelit), can be performed early enough during dataacquisition, and are quick enough, that it is feasible to pause tooptimize the data collection strategy.
Date: January 9, 2006
Creator: Sauter, Nicholas K.; Grosse-Kunstleve, Ralf W. & Adams, Paul D.
Object Type: Article
System: The UNT Digital Library
21st Century Locomotive Technology: Quarterly Technical Status Report 13 DOE/AL68284-TSR13 (open access)

21st Century Locomotive Technology: Quarterly Technical Status Report 13 DOE/AL68284-TSR13

Upgrades and calibrations were performed on the single cylinder engine. Production of a baseline engine performance dataset has started using GE Evolution engine hardware, including the production unit pump fuel system. Long-term tests of battery cells energized at room temperature were performed. Hybrid energy storage capabilities were added to the fuel optimizer.
Date: May 9, 2006
Creator: Salasoo, Lembit & Topinka, Jennifer
Object Type: Report
System: The UNT Digital Library
Repackaging SRS Black Box TRU Waste (open access)

Repackaging SRS Black Box TRU Waste

Historically, large items of TRU Waste, which were too large to be packaged in drums for disposal have been packaged in various sizes of custom made plywood boxes at the Savannah River Site (SRS), for many years. These boxes were subsequently packaged into large steel ''Black Boxes'' for storage at SRS, pending availability of Characterization and Certification capability, to facilitate disposal of larger items of TRU Waste. There are approximately 107 Black Boxes in inventory at SRS, each measuring some 18' x 12' x 7', and weighing up to 45,000 lbs. These Black Boxes have been stored since the early 1980s. The project to repackage this waste into Standard Large Boxes (SLBs), Standard Waste Boxes (SWB) and Ten Drum Overpacks (TDOP), for subsequent characterization and WIPP disposal, commenced in FY04. To date, 10 Black Boxes have been repackaged, resulting in 40 SLB-2's, and 37 B25 overpack boxes, these B25's will be overpacked in SLB-2's prior to shipping to WIPP. This paper will describe experience to date from this project.
Date: January 9, 2006
Creator: Swale, D. J.; Stone, K.A. & Milner, T. N.
Object Type: Article
System: The UNT Digital Library
Program and Abstracts, Boron Americas IX Final Report (open access)

Program and Abstracts, Boron Americas IX Final Report

The Scientific and Technical Information (STI) submitted includes the final report and a collection of abstracts for the Ninth Boron in the Americas Conference which was held May 19-22, 2004, in San Marcos, Texas. The topics covered in the abstracts include: Application in Medicine, Application in Organic Synthesis and Catalysis, Boranes and Carboranes, Materials and Polymers, Metallaboranes and Metallacarboranes, Organoboron Compounds, Synthesis and Catalysis, and Theoretical Studies. Attendees represented researchers from government, industry, and academia.
Date: August 9, 2006
Creator: Feakes, Debra A.
Object Type: Report
System: The UNT Digital Library
Development of a Method for Measuring Carbon Balance in Chemical Sequestration of CO2 (open access)

Development of a Method for Measuring Carbon Balance in Chemical Sequestration of CO2

Anthropogenic CO2 released from fossil fuel combustion is a primary greenhouse gas which contributes to “global warming.” It is estimated that stationary power generation contributes over one-third of total CO2 emissions. Reducing CO2 in the atmosphere can be accomplished either by decreasing the rate at which CO2 is emitted into the atmosphere or by increasing the rate at which it is removed from it. Extensive research has been conducted on determining a fast and inexpensive method to sequester carbon dioxide. These methods can be classified into two categories, CO2 fixation by natural sink process for CO2, or direct CO2 sequestration by artificial processes. In direct sequestration, CO2 produced from sources such as coal-fired power plants, would be captured from the exhausted gases. CO2 from a combustion exhaust gas is absorbed with an aqueous ammonia solution through scrubbing. The captured CO2 is then used to synthesize ammonium bicarbonate (ABC or NH4HCO3), an economical source of nitrogen fertilizer. In this work, we studied the carbon distribution after fertilizer is synthesized from CO2. The synthesized fertilizer in laboratory is used as a “CO2 carrier” to “transport” CO2 from the atmosphere to crops. After biological assimilation and metabolism in crops treated with ABC, a …
Date: September 9, 2006
Creator: Cheng, Zhongxian; Pan, Wei-Ping & Riley, John T.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT AND CHARACTERIZATION OF NOVEL COMPLEX HYDRIDESSYNTHESIZED VIA MOLTEN STATE PROCESSING (open access)

DEVELOPMENT AND CHARACTERIZATION OF NOVEL COMPLEX HYDRIDESSYNTHESIZED VIA MOLTEN STATE PROCESSING

This study developed novel hydrides for hydrogen storage through a novel synthesis technique utilizing high hydrogen overpressure at elevated temperatures denoted as Molten State Processing, MSP. The ultimate goal is to produce materials that have high hydrogen capacity, are stable after cycling and possess favorable thermodynamic and kinetic characteristics compatible with onboard hydrogen storage for automotive applications. In order to achieve these goals the MSP Process was developed and used to modify and form new complex hydride compounds with desired characteristics. This synthesis technique holds the potential of fusing different known complex hydrides at elevated temperatures and pressures to form new complexes having different sorption and thermodynamic properties. The new complex hydrides produced by this method were identified through structural determination and thermodynamic characterization in order to achieve a more fundamental understanding of their formation and dissociation mechanisms.
Date: January 9, 2006
Creator: Zidan, R
Object Type: Article
System: The UNT Digital Library