The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration (open access)

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration

The objective of this research project is to develop the necessary thermodynamic data, including aqueous phase stability constants and Pitzer ion-interaction parameters, to predict the changes in the aqueous phase chemistry that occur when high ionic strength, highly basic tank wastes enter the vadose zone.
Date: December 1, 2004
Creator: Choppin, Gregory R.
Object Type: Report
System: The UNT Digital Library
Analysis of Savannah Survey Sediment Collections of 30 Sep 04 (open access)

Analysis of Savannah Survey Sediment Collections of 30 Sep 04

This report summarizes laboratory radiochemical analyses of sediment samples collected by the Defense Threat Reduction Agency during the DoD Savannah Survey operations of Sep 04. The analytic goal was to determine if Wassaw Sound sediment collections of 30 Sep 04 display evidence for local anthropogenic uranium, as distinct from the recognized regional background stemming from the Savannah River Site (SRS). Radiochemical methods were selected to maximize detection sensitivity for such anthropogenic uranium. Within the suite of twelve collections, there would be evidence for a localized source if individual collections were to differ from the population as a whole. If in fact non-natural uranium were observed, definitive determination of whether the source was SRS effluent or a localized release would likely involve additional field sampling. These collections were logged by the LLNL Forensics Science Center, photographed, and laboratory chain-of-custody was begun. The inventory received at LLNL is reported in Table 1. The separate collections were not assigned any relative priority among them. LLNL has separately reviewed detailed records of the item in question, and determined what materials are involved and what radiochemical assays are of value. Attempting quantitative estimates of source-item material release, transport, and collection levels would be quite uncertain. …
Date: December 3, 2004
Creator: Wimer, N. G.; Hutcheon, I. D.; Esser, B. K. & Ramon, E. C.
Object Type: Report
System: The UNT Digital Library
Toward the Automated Generation of Components from Existing Source Code (open access)

Toward the Automated Generation of Components from Existing Source Code

A major challenge to achieving widespread use of software component technology in scientific computing is an effective migration strategy for existing, or legacy, source code. This paper describes initial work and challenges in automating the identification and generation of components using the ROSE compiler infrastructure and the Babel language interoperability tool. Babel enables calling interfaces expressed in the Scientific Interface Definition Language (SIDL) to be implemented in, and called from, an arbitrary combination of supported languages. ROSE is used to build specialized source-to-source translators that (1) extract a SIDL interface specification from information implicit in existing C++ source code and (2) transform Babel's output to include dispatches to the legacy code.
Date: December 2, 2004
Creator: Quinlan, Daniel; Yi, Qing; Kumfert, Gary; Epperly, Thomas; Dahlgren, Tamara; Schordan, Markus et al.
Object Type: Article
System: The UNT Digital Library
Loops in Reeb Graphs of 2-Manifolds (open access)

Loops in Reeb Graphs of 2-Manifolds

Given a Morse function f over a 2-manifold with or without boundary, the Reeb graph is obtained by contracting the connected components of the level sets to points. We prove tight upper and lower bounds on the number of loops in the Reeb graph that depend on the genus, the number of boundary components, and whether or not the 2-manifold is orientable. We also give an algorithm that constructs the Reeb graph in time O(n log n), where n is the number of edges in the triangulation used to represent the 2-manifold and the Morse function.
Date: December 16, 2004
Creator: Cole-McLaughlin, Kree; Edelsbrunner, Herbert; Harer, John; Natarajan, Vijay & Pascucci, Valerio
Object Type: Article
System: The UNT Digital Library
Local and Global Comparison of Continuous Functions (open access)

Local and Global Comparison of Continuous Functions

We introduce local and global comparison measures for a collection of k {<=} d real-valued smooth functions on a common d-dimensional Riemannian manifold. For k = d = 2 we relate the measures to the set of critical points of one function restricted to the level sets of the other. The definition of the measures extends to piecewise linear functions for which they are easy to compute. The computation of the measures forms the centerpiece of a software tool which we use to study scientific datasets.
Date: December 16, 2004
Creator: Edelsbrunner, Herbert; Harer, John; Natarajan, Vijay & Pascucci, Valerio
Object Type: Article
System: The UNT Digital Library
Drama in Dynamics: Boom, Splash, and Speed (open access)

Drama in Dynamics: Boom, Splash, and Speed

The full nature of chemistry and physics cannot be captured by static calculations alone. Dynamics calculations allow the simulation of time-dependent phenomena. This facilitates both comparisons with experimental data and the prediction and interpretation of details not easily obtainable from experiments. Simulations thus provide a direct link between theory and experiment, between microscopic details of a system and macroscopic observed properties. Many types of dynamics calculations exist. The most important distinction between the methods and the decision of which method to use can be described in terms of the size and type of molecule/reaction under consideration and the type and level of accuracy required in the final properties of interest. These considerations must be balanced with available computational codes and resources as simulations to mimic ''real-life'' may require many time steps. As indicated in the title, the theme of this thesis is dynamics. The goal is to utilize the best type of dynamics for the system under study while trying to perform dynamics in the most accurate way possible. As a quantum chemist, this involves some level of first principles calculations by default. Very accurate calculations of small molecules and molecular systems are now possible with relatively high-level ab initio …
Date: December 19, 2004
Creator: Netzloff, Heather M.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
PREFERENTIAL RECYCLING/REJECTION IN CFBC/FBC SYSTEMS USING TRIBOELECTROSTATIC SEPARATION (open access)

PREFERENTIAL RECYCLING/REJECTION IN CFBC/FBC SYSTEMS USING TRIBOELECTROSTATIC SEPARATION

Circulating Fluidized Bed Combustion (CFBC) and Fluidized Bed Combustion (FBC) with recirculation are widely used technologies in the US for power generation. They have the advantage of fuel flexibility, and low NO{sub x} and SO{sub x} emissions. Typically, as partially combusted fuel is circulated in the system, only a split stream of this circulating stream is rejected, with the remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used and valuable calcium hydroxide in the reject stream. If these useful materials in the reject stream can be recovered and sent back to the combustor, the efficiency of the system will be increased significantly and the equivalent emissions will be lower. This project studies an innovative concept to incorporate triboelectric separation into CFBC/FBC systems in order to preferentially split its recycle/reject streams based on material compositions of the particles. The objective is to answer whether useful constituents, like carbon, calcium carbonate and calcium hydroxide or oxide, can be selectively separated from combustion ash at elevated temperatures. Laboratory experimental studies are performed at temperatures from 25 C to 210 C,the data from which are presented in the form of recovery curves. These curves present quality-versus-quantity information useful …
Date: December 1, 2004
Creator: Ban, Heng & Stencel, John M.
Object Type: Report
System: The UNT Digital Library
IMPROVED OIL RECOVERY FROM UPPER JURASSIC SMACKOVER CARBONATES THROUGH THE APPLICATION OF ADVANCED TECHNOLOGIES AT WOMACK HILL OIL FIELD, CHOCTAW AND CLARKE COUNTIES, ALABAMA, EASTERN GULF COASTAL PLAIN (open access)

IMPROVED OIL RECOVERY FROM UPPER JURASSIC SMACKOVER CARBONATES THROUGH THE APPLICATION OF ADVANCED TECHNOLOGIES AT WOMACK HILL OIL FIELD, CHOCTAW AND CLARKE COUNTIES, ALABAMA, EASTERN GULF COASTAL PLAIN

The principal research effort for Year 1 of the project is drilling an infill well in the Womack Hill Field, Choctaw and Clarke Counties, Alabama. The objectives of the project are to drill and core an infill well in Womack Hill Field; to utilize samples from the core to evaluate further the feasibility of implementing an immobilized enzyme technology project in the field; and to use the new information resulting from the drilling of the well to revise and modify the 3-D geologic model, to further modify the injection strategy for the existing pressure maintenance program, and to assess whether a second infill well should be drilled using lateral/multilateral well completions.
Date: December 13, 2004
Creator: Mancini, Ernest A.
Object Type: Report
System: The UNT Digital Library
IMPROVED OIL RECOVERY FROM UPPER JURASSIC SMACKOVER CARBONATES THROUGH THE APPLICATION OF ADVANCED TECHNOLOGIES AT WOMACK HILL OIL FIELD, CHOCTAW AND CLARKE COUNTIES, ALABAMA, EASTERN GULF COASTAL PLAIN (open access)

IMPROVED OIL RECOVERY FROM UPPER JURASSIC SMACKOVER CARBONATES THROUGH THE APPLICATION OF ADVANCED TECHNOLOGIES AT WOMACK HILL OIL FIELD, CHOCTAW AND CLARKE COUNTIES, ALABAMA, EASTERN GULF COASTAL PLAIN

The principal research effort for Year 1 of the project is drilling an infill well in the Womack Hill Field, Choctaw and Clarke Counties, Alabama. The objectives of the project are to drill and core an infill well in Womack Hill Field; to utilize samples from the core to evaluate further the feasibility of implementing an immobilized enzyme technology project in the field; and to use the new information resulting from the drilling of the well to revise and modify the 3-D geologic model, to further modify the injection strategy for the existing pressure maintenance program, and to assess whether a second infill well should be drilled using lateral/multilateral well completions.
Date: December 6, 2004
Creator: Mancini, Ernest A.
Object Type: Report
System: The UNT Digital Library
NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS (open access)

NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS

Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this proposed project is to develop a technology for on-line corrosion monitoring based on a new concept. This report describes the initial results from the first-year effort of the three-year study that include laboratory development and experiment, and pilot combustor testing.
Date: December 1, 2004
Creator: Ban, Heng
Object Type: Report
System: The UNT Digital Library
DESIGN AND EVALUATION OF IONIC LIQUIDS AS NOVEL CO2 ABSORBENTS (open access)

DESIGN AND EVALUATION OF IONIC LIQUIDS AS NOVEL CO2 ABSORBENTS

Progress from the first quarter of activity on the project ''Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'' is provided. Major activities in three areas are reported: ''assembling equipment and a research team, compound synthesis and molecular modeling''. Nine new ionic liquid compounds have been made or acquired, and are in line for physical property testing to assess their potential for CO{sub 2} sequestration. Quantum mechanical calculations between CO{sub 2} and different ionic liquids have been conducted. The simulations have shed light on the nature of interactions between CO{sub 2} and the ionic liquids, and are providing insight that will be used to suggest new compounds to be synthesized and tested.
Date: December 31, 2004
Creator: Maginn, Edward J.
Object Type: Report
System: The UNT Digital Library
Direct Investigations of the Immobilization of Radionuclides in the Alteration Products of Spent Nuclear Fuel (open access)

Direct Investigations of the Immobilization of Radionuclides in the Alteration Products of Spent Nuclear Fuel

Safe disposal of the nation's nuclear waste in a geological repository involves unique scientific and engineering challenges owing to the very long-lived radioactivity of the waste. The repository must retain a variety of radionuclides that have vastly different chemical characters for several thousand years. Most of the radioactivity that will be housed in the proposed repository at Yucca Mountain will be associated with spent nuclear fuel, much of which is derived from commercial reactors. DOE is custodian of approximately 8000 tons of spent nuclear fuel that is also intended for eventual disposal in a geological repository. Unlike the spent fuel from commercial reactors, the DOE fuel is diverse in composition with more than 250 varieties. Safe disposal of spent fuel requires a detailed knowledge of its long-term behavior under repository conditions, as well as the fate of radionuclides released from the spent fuel as waste containers are breached.
Date: December 27, 2004
Creator: Burns, Peter C.; Finch, Robert J. & Wronkiewicz, David J.
Object Type: Report
System: The UNT Digital Library
Dissolution of Fe(III)(hydr)oxides by an Aerobic Bacterium (open access)

Dissolution of Fe(III)(hydr)oxides by an Aerobic Bacterium

This project investigated the effects of an aerobic Pseudomonas mendocina bacterium on the dissolution of Fe(III)(hydr)oxides. The research is important because metals and radionuclides that adsorb to Fe(III)(hydr)oxides could potentially be remobilized by dissolving bacteria. We showed that P. mendocina is capable of dissolving Fe-bearing minerals by a variety of mechanisms, including production of siderophores, pH changes, and formation of reductants. The production of siderophores by P. mendocina was quantified under a variety of growth conditions. Finally, we demonstrated that microbial siderophores may adsorb to and enhance dissolution of clay minerals.
Date: December 13, 2004
Creator: Maurice, P.
Object Type: Report
System: The UNT Digital Library
Application of the SAMGrid Test-Harness for Performance Evaluation and Tuning of a Distributed Cluster Implementation of Data Handling Services (open access)

Application of the SAMGrid Test-Harness for Performance Evaluation and Tuning of a Distributed Cluster Implementation of Data Handling Services

The SAMGrid team has recently refactored its test harness suite for greater flexibility and easier configuration. This makes possible more interesting applications of the test harness, for component tests, integration tests, and stress tests. This new implementation of the test harness is a Python framework which uses XML for configuration and small plug-in python modules for specific test purposes We report on the architecture of the test harness and its recent application to stress tests of a new analysis cluster at Fermilab, to explore the extremes of analysis use cases and the relevant parameters for tuning in the SAMGrid station services. One current testing application is running on a 128-CPU analysis cluster with access to 6 TB distributed cache and also to a 2 TB centralized cache, permitting studies of different cache strategies. We have also studied the service parameters which affect the performance of retrieving data from tape storage. The use cases studied vary from those which will require rapid file delivery with short processing time per file, to the opposite extreme of long processing time per file. These results are interesting for their implications with regard to Grid operations, and illustrate the type of monitoring and test facilities …
Date: December 1, 2004
Creator: Lyon, A.; Baranovski, A.; Garzoglio, G.; Loebel-Carpenter, L.; Herber, R.; Illingworth, R. et al.
Object Type: Article
System: The UNT Digital Library
Search for CP violation in charged-Xi and Lambda hyperon decays (open access)

Search for CP violation in charged-Xi and Lambda hyperon decays

The authors have compared the p and {bar p} angular distributions in 117 million {Xi}{sup -} {yields} {Lambda}{pi}{sup -} {yields} p{pi}{sup -}{pi}{sup -} and 41 million {Xi}{sup +} {yields} {bar {Lambda}}{pi}{sup +} {yields} {bar p}{pi}{sup +}{pi}{sup +} decays using a subset of the data from the HyperCP experiment (ES71) at Fermilab. They find no evidence of CP violation, with the direct-CP-violating parameter A{sub {Xi}{Lambda}} {triple_bond} (a{sub {Xi}}a{sub {Lambda}} - {bar a}{sub {Xi}}{bar a}{sub {Lambda}})/(a{sub {Xi}}a{sub {Lambda}} + {bar a}{sub {Xi}}{bar a}{sub {Lambda}}) = [0.0 {+-} 5.1(stat) {+-} 4.4(syst)] x 10{sup -4}.
Date: December 1, 2004
Creator: Holmstrom, T.; Leros, N.; Burnstein, R. A.; Chakravorty, A.; Chan, A.; Chen, Y. C. et al.
Object Type: Article
System: The UNT Digital Library
First measurement of sigma (p anti-p ---> Z) . Br (Z ---> tau tau) at s**(1/2) = 1.96- TeV (open access)

First measurement of sigma (p anti-p ---> Z) . Br (Z ---> tau tau) at s**(1/2) = 1.96- TeV

The authors present a measurement of the cross section for Z production times the branching fraction to {tau} leptons, {sigma} {center_dot} Br(Z {yields} {tau}{sup +}{tau}{sup -}), in p{bar p} collisions at {radical}s = 1.96 TeV in the channel in which one {tau} decays into {mu}{nu}{sub {mu}}{nu}{sub {tau}}, and the other into hadrons + {nu}{sub {tau}} or e{nu}{sub e}{nu}{sub {tau}}. The data sample corresponds to an integrated luminosity of 226 pb{sup -1} collected with the D0 detector at the Fermilab Tevatron collider. The final sample contains 2008 candidate events with an estimated background of 55%. From this they obtain {sigma} {center_dot} Br(Z {yields} {tau}{sup +}{tau}{sup -}) = 237 {+-} 15(stat) {+-} 18(sys) {+-} 15(lum) pb, in agreement with the standard model prediction.
Date: December 1, 2004
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Search for first-generation scalar leptoquarks in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for first-generation scalar leptoquarks in p anti-p collisions at s**(1/2) = 1.96-TeV

The authors report on a search for pair production of first-generation scalar leptoquarks (LQ) in p{bar p} collisions at {radical}s = 1.96 TeV using an integrated luminosity of 252 pb{sup -1} collected at the Fermilab Tevatron collider by the D0 detector. They observe no evidence for LQ production in the topologies arising from LQ{ovr LQ} {yields} eqeq and LQ{ovr LQ} {yields} eqvq, and derive 95% C.L. lower limits on the LQ mass as a function of {beta}, where {beta} is the branching fraction for LQ {yields} eq. The limits are 241 and 218 GeV/c{sup 2} for {beta} = 1 and 0.5, respectively. These results are combined with those obtained by D0 at {radical}s = 1.8 TeV, which increases these LQ mass limits to 256 and 234 GeV/c{sup 2}.
Date: December 1, 2004
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Deterministic, Nanoscale Fabrication of Mesoscale Objects (open access)

Deterministic, Nanoscale Fabrication of Mesoscale Objects

Neither LLNL nor any other organization has the capability to perform deterministic fabrication of mm-sized objects with arbitrary, {micro}m-sized, 3-D features and with 100-nm-scale accuracy and smoothness. This is particularly true for materials such as high explosives and low-density aerogels, as well as materials such as diamond and vanadium. The motivation for this project was to investigate the physics and chemistry that control the interactions of solid surfaces with laser beams and ion beams, with a view towards their applicability to the desired deterministic fabrication processes. As part of this LDRD project, one of our goals was to advance the state of the art for experimental work, but, in order to create ultimately a deterministic capability for such precision micromachining, another goal was to form a new modeling/simulation capability that could also extend the state of the art in this field. We have achieved both goals. In this project, we have, for the first time, combined a 1-D hydrocode (''HYADES'') with a 3-D molecular dynamics simulator (''MDCASK'') in our modeling studies. In FY02 and FY03, we investigated the ablation/surface-modification processes that occur on copper, gold, and nickel substrates with the use of sub-ps laser pulses. In FY04, we investigated laser …
Date: December 8, 2004
Creator: Mariella, R., Jr.; Gilmer, J.; Rubenchik, A. & Shirk, M.
Object Type: Report
System: The UNT Digital Library
Development of an Environmentally Benign Microbial Inhibitor to Control Internal Pipeline Corrosion: Final Report (open access)

Development of an Environmentally Benign Microbial Inhibitor to Control Internal Pipeline Corrosion: Final Report

The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Various chemicals that inhibit the growth and/or the metabolism of corrosion-associated microbes such as sulfate reducing bacteria, denitrifying bacteria, and methanogenic bacteria were evaluated to determine their ability to inhibit corrosion in experiments utilizing pure and mixed bacterial cultures, and planktonic cultures as well as mature biofilms. Planktonic cultures are easier to inhibit than mature biofilms but several compounds were shown to be effective in decreasing the amount of metal corrosion. Of the compounds tested hexane extracts of Capsicum pepper plants and molybdate were the most effective inhibitors of sulfate reducing bacteria, bismuth nitrate was the most effective inhibitor of nitrate reducing bacteria, and 4-((pyridine-2-yl)methylamino)benzoic acid (PMBA) was the most effective inhibitor of methanogenic bacteria. All of these compounds were demonstrated to minimize corrosion due to MIC, at least in some circumstances. The results obtained …
Date: December 1, 2004
Creator: Bogan, Bill W.; Lamb, Brigid M.; Husmillo, Gemma; Lowe, Kristine; Paterek, J. Robert & Kilbane, John J., II
Object Type: Report
System: The UNT Digital Library
Molecular Characterization of the Role of a Calcium Channel in Plant Development (open access)

Molecular Characterization of the Role of a Calcium Channel in Plant Development

A stimulus-induced change in cellular Ca2+ levels is a critical component of energy transduction in plant and animal development. Demonstrating Ca2+'s involvement in any developmental process requires identification of mechanisms that regulate these Ca2+ changes. In plants, biochemical studies have implicated the activity of Ca2+ channels in increases in cellular Ca2+ levels; however, molecular evidence for these transporters is lacking. Our studies used the mosses Physcomitrella patens and Funaria hygrometrica to establish a role for Ca2+ in hormone-induced morphogenesis and to use this developmental process to identify transporters responsible for increasing cytosolic Ca2+ levels. Using 1,4-dihydropyridines (DHPs), molecules that block Ca2+ movement through voltage-dependent channels in animal cells, we have shown that Ca2+ is important early in the transition from filamentous to meristematic-like growth that occurs in response to the plant hormone cytokinin. In addition to inhibiting moss growth (see below), these Ca2+ channel blockers prevent Ca2+ transport into moss cells (Schumaker and Gizinski, 1993) and bind specifically to two proteins in the moss plasma membrane (Schumaker and Gizinski, 1994; 1996; Dietrich et al., unpublished results). We used tandem mass spectrometry of the partially purified DHP-binding proteins with the goal of identifying the putative Ca2+ channel and providing sequence information …
Date: December 21, 2004
Creator: Schumaker, Karen S.
Object Type: Report
System: The UNT Digital Library