Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance (open access)

Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes
Date: December 11, 2004
Creator: Bowman-James, K.; Wilson, G. & Moyer, B. A.
Object Type: Report
System: The UNT Digital Library
Top quark mass measurement at CDF Run-II (open access)

Top quark mass measurement at CDF Run-II

CDF has resumed the top quark mass measurement with upgraded detectors and Tevatron complex. High statistics should allow us to determine the top mass with an uncertainty of a few GeV/c{sup 2} by the end of Run II. The current measured value, using an integrated luminosity of {approx} 108 pb{sup -1}, is 177.5{sub -9.4}{sup +12.7} (stat.) {+-} 7.1(syst.) GeV/c{sup 2} (lepton + jets with one b-jet tagged mode: the current best mode), which is consistent with RunI measurements.
Date: May 11, 2004
Creator: Maruyama, T.
Object Type: Article
System: The UNT Digital Library
Leptogenesis from split fermions (open access)

Leptogenesis from split fermions

We present a new type of leptogenesis mechanism based on a two-scalar split-fermions framework. At high temperatures the bulk scalar vacuum expectation values (VEVs) vanish and lepton number is strongly violated. Below some temperature, T{sub c}, the scalars develop extra dimension dependent VEVs. This transition is assumed to proceed via a first order phase transition. In the broken phase the fermions are localized and lepton number violation is negligible. The lepton-bulk scalar Yukawa couplings contain sizable CP phases which induce lepton production near the interface between the two phases. We provide a qualitative estimation of the resultant baryon asymmetry which agrees with current observation. The neutrino flavor parameters are accounted for by the above model with an additional approximate U(1) symmetry.
Date: January 11, 2004
Creator: Nagatani, Yukinori & Perez, Gilad
Object Type: Article
System: The UNT Digital Library
Diagnostics for intense heavy ion beams in the HIF-VNL (open access)

Diagnostics for intense heavy ion beams in the HIF-VNL

Modern diagnostic techniques provide detailed information on beam conditions in injector, transport, and final focus experiments in the HIF-VNL. Parameters of interest include beam current, beam energy, transverse and longitudinal distributions, emittance, and space charge neutralization. Imaging techniques, based on kapton films and optical scintillators, complement and in some cases, may replace conventional techniques based on slit scans. Time-resolved optical diagnostics that provide 4-D transverse information on the experimental beams are in operation on the existing experiments. Current work includes a compact optical diagnostic suitable for insertion in transport lines, improved algorithms for optical data analysis and interpretation, a high-resolution electrostatic energy analyzer, and an electron beam probe. A longitudinal diagnostic kicker generates longitudinal space-charge waves that travel on the beam. Time of flight of the space charge waves and an electrostatic energy analyzer provide an absolute measure of the beam energy. Special diagnostics to detect secondary electrons and gases desorbed from the wall have been developed.
Date: June 11, 2004
Creator: Bieniosek, F. M.; Eylon, S.; Faltens, A.; Friedman, A.; Kwan, J. W.; Leitner, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Real-time Equilibrium Reconstruction and Isoflux Control of Plasma Shape and Position in the National Spherical Torus Experiment (NSTX) (open access)

Real-time Equilibrium Reconstruction and Isoflux Control of Plasma Shape and Position in the National Spherical Torus Experiment (NSTX)

The implementation of the rtEFIT-isoflux algorithm in the digital control system for NSTX has led to improved ability to control the plasma shape. In particular, it has been essential for good gap control for radio-frequency experiments, for control of drsep in H-mode studies, and for X-point height control and {kappa} control in a variety of experiments.
Date: August 11, 2004
Creator: Mueller, D.; Gates, D. A.; Menard, J. E.; Ferron, J. R. & Sabbagh, S. A.
Object Type: Report
System: The UNT Digital Library
Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications (open access)

Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications

An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors.
Date: August 11, 2004
Creator: Anghaie, Samim; Knight, Travis W.; Plancher, Johann & Gouw, Reza
Object Type: Report
System: The UNT Digital Library
An Application of the Coda Methodology for Moment-Rate Spectra Using Broadband Stations in Turkey (open access)

An Application of the Coda Methodology for Moment-Rate Spectra Using Broadband Stations in Turkey

A recently developed coda magnitude methodology was applied to selected broadband stations in Turkey for the purpose of testing the coda method in a large, laterally complex region. As found in other, albeit smaller regions, coda envelope amplitude measurements are significantly less variable than distance-corrected direct wave measurements (i.e., L{sub g} and surface waves) by roughly a factor 3-to-4. Despite strong lateral crustal heterogeneity in Turkey, they found that the region could be adequately modeled assuming a simple 1-D, radially symmetric path correction. After calibrating the stations ISP, ISKB and MALT for local and regional distances, single-station moment-magnitude estimates (M{sub W}) derived from the coda spectra were in excellent agreement with those determined from multistation waveform modeling inversions, exhibiting a data standard deviation of 0.17. Though the calibration was validated using large events, the results of the calibration will extend M{sub W} estimates to significantly smaller events which could not otherwise be waveform modeled. The successful application of the method is remarkable considering the significant lateral complexity in Turkey and the simple assumptions used in the coda method.
Date: July 11, 2004
Creator: Eken Tuna, Kevin Mayeda, Abraham Hofstetter, Rengin Gok, Gonca Orgulu, Niyazi Turkelli
Object Type: Article
System: The UNT Digital Library
Geochemistry of Hydrofluoric Acid in Kaolinitic Soils (open access)

Geochemistry of Hydrofluoric Acid in Kaolinitic Soils

This document explores the geochemical reactions likely to occur when hydrofluoric acid is spilled on Savannah River Site (SRS) soil. In particular, we evaluate the potential of environmental damage from a one-time release of concentrated hydrofluoric acid into a trench. According to interviews with personnel involved, sometime between 1955 and 1960 drums of 50-60 per cent hydrofluoric acid were disposed in a trench in the Central Shops area. The method of disposal suggests that most of the acid would have been released at the time of burial. No evidence of drum disposal or acidic pH values was found. Therefore, the Soil and Groundwater Closure Projects group requested that we evaluate potential risk by examining the major geochemical interactions expected between hydrofluoric acid and soil. The geochemical calculations in this report were done with The Geochemist's Workbench (Registered). This program uses an extended Debye-Huckel method for calculating activity coefficients. The conclusions of this report are accurate, but some of the intermediate steps may have higher uncertainty. Hydrofluoric acid disposed in a trench in the area would have reacted with soil kaolinite to neutralize the pH to a value of about 4.2. Based on conservative assumptions, this would have occurred within the …
Date: May 11, 2004
Creator: DENHAM, MILES
Object Type: Report
System: The UNT Digital Library
Using Energy Information Systems (EIS): A Guidebook for the U.S. Postal Service (open access)

Using Energy Information Systems (EIS): A Guidebook for the U.S. Postal Service

The U.S. Postal Service (Postal Service) recently installed Energy Information Systems (EIS) at 30 facilities in California. These systems integrate electric utility meter data acquisition hardware, software, and communication systems to collect, archive, analyze, and display whole-facility energy consumption data. At some point in the future, these systems could also be integrated with sub-meters that measure the electricity consumption of key end-use equipment. The purpose of this guidebook is to help Postal Service facility managers interpret and act upon energy data available from their EIS, translating the abundance of information these systems provide into knowledge that can be used to reduce energy use and costs. The guidebook first describes basic EIS capabilities and explains the data and reports that Postal Service EIS provide. It outlines a set of strategies for utilizing this information to improve operations and maintenance of building energy use equipment and for facilitating demand response. Finally, the guidebook offers suggestions on creating a routine for tracking and analyzing energy data and integrating this information into regular energy management activities.
Date: October 11, 2004
Creator: Foster, Dale; Hough, Ben; Barbose, Galen; Golove, William & Goldman, Charles
Object Type: Report
System: The UNT Digital Library
Vibroseis Monitoring of San Andreas Fault in California (open access)

Vibroseis Monitoring of San Andreas Fault in California

A unique data set of seismograms for 720 source-receiver paths has been collected as part of a controlled source Vibroseis experiment San Andreas Fault (SAF) at Parkfield. In the experiment, seismic waves repeatedly illuminated the epicentral region of the expected M6 event at Parkfield from June 1987 until November 1996. For this effort, a large shear-wave vibrator was interfaced with the 3-component (3-C) borehole High-Resolution Seismic Network (HRSN), providing precisely timed collection of data for detailed studies of changes in wave propagation associated with stress and strain accumulation in the fault zone (FZ). Data collected by the borehole network were examined for evidence of changes associated with the nucleation process of the anticipated M6 earthquake at Parkfield. These investigations reported significant traveltime changes in the S coda for paths crossing the fault zone southeast of the epicenter and above the rupture zone of the 1966 M6 earthquake. Analysis and modeling of these data and comparison with observed changes in creep, water level, microseismicity, slip-at-depth and propagation from characteristic repeating microearthquakes showed temporal variations in a variety of wave propagation attributes that were synchronous with changes in deformation and local seismicity patterns. Numerical modeling suggests 200 meters as an effective thickness …
Date: June 11, 2004
Creator: Korneev, Valeri & Nadeau, Robert
Object Type: Article
System: The UNT Digital Library
Scientific Report (2002-2004) (open access)

Scientific Report (2002-2004)

OAK-B135 An overview of our work as well as two recent publications are contained in this scientific report. The work reported here revolves around the discovery of new coherent nonlinear kinetic waves in laser produced plasmas, we call KEEN waves (kinetic, electrostatic electron nonlinear waves), and optical mixing experiments on the Imega laser system at LLE with blue-green light for the exploration of ways to suppress parametric instabilities in long scale length, long pulsewidth laser-plasmas such as those which will be found on NIF or LMJ.
Date: May 11, 2004
Creator: Afeyan, Bedros
Object Type: Report
System: The UNT Digital Library
Resonance decay effects on anisotropy parameters (open access)

Resonance decay effects on anisotropy parameters

We present the elliptic flow v{sub 2} of pions produced from resonance decays. The transverse momentum p{sub T} spectra of the parent particles are taken from thermal model fits and their v{sub 2} are fit under the assumption that they follow a number-of-constituent-quark (NCQ) scaling law expected from quark-coalescence models. The v{sub 2} of pions from resonance particle decays is found to be similar to the measured pion v{sub 2}. We also propose the measurement of electron v{sub 2} as a means to extract open-charm v{sub 2} and investigate whether a thermalized system of quasi-free quarks and gluons (a quark-gluon plasma) is created in collisions of Au nuclei at RHIC.
Date: March 11, 2004
Creator: Dong, Xin; Esumi, S.; Sorensen, P.; Xu, Nu & Xu, Z.
Object Type: Article
System: The UNT Digital Library
Compositing, Homogenization, and Characterization of Samples from Hanford Tank 241-AN-107 (open access)

Compositing, Homogenization, and Characterization of Samples from Hanford Tank 241-AN-107

As part of the program to provide pretreatment development and testing services to support the River Protection Project-Waste Treatment Plant (RPP-WTP) mission to treat Hanford tank waste, an approximately 5 L sample of waste from Tank 241-AN-107 was received at the Savannah River Technology Center (SRTC). The waste sample was characterized and mixed with recycle streams to provide feed for pretreatment testing. The characterization data provides a basis for rational development of pretreatment processes, verification of tank composition,and development of physical design parameters for the pretreatment plant.
Date: March 11, 2004
Creator: Martin, K.B.
Object Type: Report
System: The UNT Digital Library
A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments (open access)

A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.
Date: May 11, 2004
Creator: Hua, F.; Mon, K.; Pasupathi, P. & Gordon, G.
Object Type: Report
System: The UNT Digital Library
NEW CATHODE MATERIALS FOR INTERMEDIATE TEMPERATURE SOLID OXIDE FUEL CELLS (open access)

NEW CATHODE MATERIALS FOR INTERMEDIATE TEMPERATURE SOLID OXIDE FUEL CELLS

Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. The initial choices for study are perovskite oxides based on Sr substituted LaFeO{sub 3}, where significant data in single cell tests exists at PNNL for cathodes on both YSZ and CSO/YSZ, and of Ln{sub 2}NiO{sub …
Date: May 11, 2004
Creator: Jacobson, Allan J.
Object Type: Report
System: The UNT Digital Library
Evaluation of the DWPF Cold Chem Dissolution Method with Tank 7 and Tank 51 Radioactive Sludge (open access)

Evaluation of the DWPF Cold Chem Dissolution Method with Tank 7 and Tank 51 Radioactive Sludge

Dissolution experiments were conducted on radioactive sludge from Tank 7, before transfer of the contents of Tank 7 to Tank 51, and the subsequent sludge in Tank 51 to evaluate the effectiveness of the DWPF Cold Chem Method. The DWPF Cold Chem Method is a room temperature dissolution method (DWPF Cold Chem Method) used in the DWPF on the Slurry Receipt and Adjustment Tank (SRAT) samples in preparation for instrumental analysis. Four types of dissolutions experiments were carried out, the DWPF Cold Chem Method, hot aqua regia, sodium peroxide fusion and hot HF-HNO3. The hot HF-HNO3 digestion is modified version of the DWPF method that incorporates a heating step. The hot aqua regia and sodium peroxide fusion digestions were included as reference digestions. The resulting solutions from all the sludge digestions were analyzed by ICP-ES (Inductively Coupled Plasma Emission Spectroscopy). Visual observations and ICP-ES results were used to evaluate the effectiveness of the DWPF Cold Chem by comparison to the hot aqua regia, sodium peroxide fusion and the hot HF-HNO3 digestions. The data and experimental observations support the following conclusions: The DWPF Cold Chem Method seemed to be effective at dissolving initial species of radioactive sludge, but concurrent precipitation of …
Date: March 11, 2004
Creator: Click, D.R.
Object Type: Report
System: The UNT Digital Library
ENHANCED RECOVERY UTILIZING VARIABLE FREQUENCY DRIVES AND A DISTRIBUTED POWER SYSTEM TECHNICAL PROGRESS REPORT (open access)

ENHANCED RECOVERY UTILIZING VARIABLE FREQUENCY DRIVES AND A DISTRIBUTED POWER SYSTEM TECHNICAL PROGRESS REPORT

This report describes the progress made during first six months of the project entitled ''Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System''. During this period, project plan, demonstration plan and project schedule were developed, equipment was ordered and baseline data was collected.
Date: February 11, 2004
Creator: Peden, Randy & Shah, Sanjiv
Object Type: Report
System: The UNT Digital Library
The Magnesium Branch of the Tetrapyrrole Biosynthetic Pathway (open access)

The Magnesium Branch of the Tetrapyrrole Biosynthetic Pathway

It should be noted that the focus of the research changed somewhat during the course of the current award. The initial focus is indicated by the title of the current grant, ''The Magnesium Branch of the Chlorophyll Biosynthetic Pathway''. During the current grant period, Dr. Robert Willows, a postdoctoral associate, joined the faculty of McQuarie University in Australia. When he left my lab, we decided that he should independently pursue research on structure/function relationships in Mg chelatase and that our laboratories would collaborate on regulatory studies of this enzyme. Also, during the current award period, I began collaborating with Dr. Ariane Atteia and Mr. Robert van Lis, who were at the time located at the Autonomous University of Mexico. Dr. Atteia has since joined my laboratory and Mr. van Lis will also do so when he obtains his Ph.D. in the near future. These individuals bring to the laboratory their interests and expertise in the respiratory components of Chlamydomonas and their desire to become experts in tetrapyrrole metabolism. Recently, in a collaboration with Dr. David Bollivar, a former postdoctoral associate who is now at Illinois Wesleyan University, and Dr. Caroline Walker, who was at Clemson University but has since left …
Date: May 11, 2004
Creator: Beale, S. I.
Object Type: Report
System: The UNT Digital Library
Measurement of Thermal Diffusity and Flow Resistance for TCAP Materials (open access)

Measurement of Thermal Diffusity and Flow Resistance for TCAP Materials

SRS uses the Thermal Cycling Absorption Process (TCAP) to separate isotopes of hydrogen. The frequency of thermal cycles is a limit of the productivity of the process and that frequency is largely determined by the thermal diffusivity of the absorbent material. For a given tube diameter, a larger thermal diffusivity decreases the time required for each cycle. In 1998, the Engineering Development Laboratory measured thermal diffusivity and thermal conductivity for three TCAP materials in helium.
Date: November 11, 2004
Creator: Steimke, John
Object Type: Report
System: The UNT Digital Library
The impact of covariance information on criticality safety calculations in the resolved resonance energy range. (open access)

The impact of covariance information on criticality safety calculations in the resolved resonance energy range.

Resonance data play a significant role in the calculations of systems considered for criticality safety applications. K{sub eff}, the major parameter of interest in such a type of calculations, can be heavily dependent both on the quality of the resonance data as well as on the accuracy achieved in the processing of these data. If reasonable uncertainty values are available, in conjunction with their correlation in energy and among type of resonance parameters, one can exploit existing methodologies, based on perturbation theory, in order to evaluate their impact on the integral parameter of interest, i.e., K{sub eff} in our case, in practical applications. In this way, one could be able to judge if the uncertainty on specific quantities, e.g., covariances on resonance data, have a significant impact and, therefore, deserve a careful evaluation. This report, first, will recall the basic principles that lie behind an uncertainty evaluation and review the current situation in the field of covariance data. Then an attempt is made for defining a methodology that allows calculating covariances values for resolved resonance parameters. Finally, practical applications, of interest for criticality safety calculations, illustrate the impact of different assumptions on correlations among resolved resonance parameters.
Date: June 11, 2004
Creator: Naberejnev, D. G.; Palmiotti, G. & Yang, W. S.
Object Type: Report
System: The UNT Digital Library
Hamiltonian Description of Convective-cell Generation (open access)

Hamiltonian Description of Convective-cell Generation

The nonlinear statistical growth rate eq for convective cells driven by drift-wave (DW) interactions is studied with the aid of a covariant Hamiltonian formalism for the gyrofluid nonlinearities. A statistical energy theorem is proven that relates eq to a second functional tensor derivative of the DW energy. This generalizes to a wide class of systems of coupled partial differential equations a previous result for scalar dynamics. Applications to (i) electrostatic ion-temperature-gradient-driven modes at small ion temperature, and (ii) weakly electromagnetic collisional DW's are noted.
Date: March 11, 2004
Creator: Krommes, J. A. & Kolesnikov, R. A.
Object Type: Report
System: The UNT Digital Library
Performance characteristics of the Cray X1 and their implicationsfor application performance tuning (open access)

Performance characteristics of the Cray X1 and their implicationsfor application performance tuning

During the last decade the scientific computing community has optimized many applications for execution on superscalar computing platforms. The recent arrival of the Japanese Earth Simulator has revived interest in vector architectures especially in the US. It is important to examine how to port our current scientific applications to the new vector platforms and how to achieve high performance. The success of porting these applications will also influence the acceptance of new vector architectures. In this paper, we first investigate the memory performance characteristics of the Cray X1, a recently released vector platform, and determine the most influential performance factors. Then, we examine how to optimize applications tuned on superscalar platforms for the Cray X1 using its performance characteristics as guidelines. Finally, we evaluate the different types of optimizations used, the effort for their implementations, and whether they provide any performance benefits when ported back to superscalar platforms.
Date: May 11, 2004
Creator: Shan, Hogzhang & Strohmaier, Erich
Object Type: Article
System: The UNT Digital Library
A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States (open access)

A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States

For years, farmers in the United States have looked with envy on their European counterparts' ability to profitably farm the wind through ownership of distributed, utility-scale wind projects. Only within the past few years, however, has farmer- or community-owned wind power development become a reality in the United States. The primary hurdle to this type of development in the United States has been devising and implementing suitable business and legal structures that enable such projects to take advantage of tax-based federal incentives for wind power. This article discusses the limitations of such incentives in supporting farmer- or community-owned wind projects, describes four ownership structures that potentially overcome such limitations, and finally conducts comparative financial analysis on those four structures, using as an example a hypothetical 1.5 MW farmer-owned project located in the state of Oregon. We find that material differences in the competitiveness of each structure do exist, but that choosing the best structure for a given project will largely depend on the conditions at hand; e.g., the ability of the farmer(s) to utilize tax credits, preference for individual versus ''cooperative'' ownership, and the state and utility service territory in which the project will be located.
Date: November 11, 2004
Creator: Bolinger, Mark & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
Evaluation of Proposed New LLW Disposal Activity Disposal of No Dose/Low Dose Scrap Metal in Slit Trenches (open access)

Evaluation of Proposed New LLW Disposal Activity Disposal of No Dose/Low Dose Scrap Metal in Slit Trenches

Activated metal is a special waste that requires evaluation for disposal. Contaminants in the activated metal will leach more slowly than will contaminants in generic waste. There is an inventory of activated scrap metal in the 105-L Disassembly Basin. Approximately 1,600 ft3 of the material is characterized as ''No Dose/Low Dose'' and consists mainly of activated aluminum and aluminum alloy pieces and parts and no stainless steel with a dose rate less than 200 mR per hr. Contaminants in the activated metal will leach more slowly than will contaminants in generic waste. The change in the leach rate will affect analyses for the groundwater pathway and intruder scenarios. For this evaluation, the slower leach rate from the activated metal waste will be neglected for the groundwater pathway, which is conservative because the higher leach rate used tends to produce higher groundwater concentrations and lower inventory limits. For this evaluation, the leach rate was set to zero for intruder scenarios, which is conservative for the inadvertent intruder because a slower leach rate will result in higher levels of radionuclides in the waste zone. The evaluation concludes that the existing limits are applicable to the disposal of No Dose/Low Dose activated scrap …
Date: February 11, 2004
Creator: Cook, J. R.
Object Type: Report
System: The UNT Digital Library