Variational formulation of the Gardner's restacking algorithm (open access)

Variational formulation of the Gardner's restacking algorithm

The incompressibility of the phase flow of Hamiltonian wave-plasma interactions restrains the class of realizable wave-driven transformations of the particle distribution. After the interaction, the distribution remains composed of the original phase-space elements, or local densities, which are only rearranged (''restacked'') by the wave. A variational formalism is developed to study the corresponding limitations on the energy and momentum transfer. A case of particular interest is a toroidal plasma immersed in a dc magnetic field. The restacking algorithm by Gardner [Phys. Fluids 6, 839 (1963)] is formulated precisely. The minimum energy state for a plasma with a given current is determined
Date: April 26, 2004
Creator: Dodin, I. Y. & Fisch, N. J.
Object Type: Report
System: The UNT Digital Library
Simulations of Bunch Merging in Booster (open access)

Simulations of Bunch Merging in Booster

N/A
Date: October 1, 2004
Creator: Gardner, C. J.
Object Type: Report
System: The UNT Digital Library
A Search for anomalous heavy-flavor quark production in association with W bosons (open access)

A Search for anomalous heavy-flavor quark production in association with W bosons

None
Date: November 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
Characterization of Vadose Zone Sediments Below the T Tank Farm: Boreholes C4104, C4105, 299-W10-196 and RCRA Borehole 299-W11-39 (open access)

Characterization of Vadose Zone Sediments Below the T Tank Farm: Boreholes C4104, C4105, 299-W10-196 and RCRA Borehole 299-W11-39

This report contains geologic, geochemical, and physical characterization data collected on sediment recovered from boreholes C4104 and C4105 in the T Tank Farm, and 299-W-11-39 installed northeast of the T Tank Farm. The measurements on sediments from borehole C4104 are compared to a nearby borehole 299-W10-196 placed through the plume from the 1973 T-106 tank leak. This report also presents the data in the context of sediment types, the vertical extent of contamination, the migration potential of the contaminants, and the likely source of the contamination in the vadose zone and groundwater below the T Tank Farm. Sediment samples were characterized for: moisture content, gamma-emission radionuclides, one-to-one water extracts (which provide soil pH, electrical conductivity, cation, trace metal, radionuclide and anion data), total carbon and inorganic carbon content, and 8 M nitric acid extracts (which provide a measure of the total leachable sediment content of contaminants). Overall, our analyses showed that common ion exchange is a key mechanism that influences the distribution of contaminants within that portion of the vadose zone affected by tank liquor. We observed slight elevated pH values in samples from borehole C4104. The sediments from the three boreholes, C4104, C4105, and 299-W10-196 do show that sodium-, …
Date: September 1, 2004
Creator: Serne, R JEFFREY.; Bjornstad, Bruce N.; Horton, Duane G.; Lanigan, David C.; Lindenmeier, Clark W.; Lindberg, Michael J. et al.
Object Type: Report
System: The UNT Digital Library
Draft versus finished sequence data for DNA and protein diagnostic signature development (open access)

Draft versus finished sequence data for DNA and protein diagnostic signature development

Sequencing pathogen genomes is costly, demanding careful allocation of limited sequencing resources. We built a computational Sequencing Analysis Pipeline (SAP) to guide decisions regarding the amount of genomic sequencing necessary to develop high-quality diagnostic DNA and protein signatures. SAP uses simulations to estimate the number of target genomes and close phylogenetic relatives (near neighbors, or NNs) to sequence. We use SAP to assess whether draft data is sufficient or finished sequencing is required using Marburg and variola virus sequences. Simulations indicate that intermediate to high quality draft with error rates of 10{sup -3}-10{sup -5} ({approx} 8x coverage) of target organisms is suitable for DNA signature prediction. Low quality draft with error rates of {approx} 1% (3x to 6x coverage) of target isolates is inadequate for DNA signature prediction, although low quality draft of NNs is sufficient, as long as the target genomes are of high quality. For protein signature prediction, sequencing errors in target genomes substantially reduce the detection of amino acid sequence conservation, even if the draft is of high quality. In summary, high quality draft of target and low quality draft of NNs appears to be a cost-effective investment for DNA signature prediction, but may lead to underestimation …
Date: October 29, 2004
Creator: Gardner, S N; Lam, M W; Smith, J R; Torres, C L & Slezak, T R
Object Type: Article
System: The UNT Digital Library
Characterization of Vadose Zone Sediments Below the TX Tank Farm: Probe Holes C3830, C3831, C3832 and 299-W10-27 (open access)

Characterization of Vadose Zone Sediments Below the TX Tank Farm: Probe Holes C3830, C3831, C3832 and 299-W10-27

Pacific Northwest National Laboratory performed detailed analyses on vadose zone sediments from within Waste Management Area T-TX-TY. This report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from three probe holes (C3830, C3831, and C3832) in the TX Tank Farm, and from borehole 299-W-10-27. Sediments from borehole 299-W-10-27 are considered to be uncontaminated sediments that can be compared with contaminated sediments. This report also presents our interpretation of the sediment lithologies, the vertical extent of contamination, the migration potential of the contaminants, and the likely source of the contamination in the vadose zone and groundwater below the TX Tank Farm. Sediment from the probe holes was analyzed for: moisture, radionuclide and carbon contents;, one-to-one water extracts (soil pH, electrical conductivity, cation, trace metal, and anion data), and 8 M nitric acid extracts. Overall, our analyses showed that common ion exchange is a key mechanism that influences the distribution of contaminants within that portion of the vadose zone affected by tank liquor. We did not observe significant indications of caustic alteration of the sediment mineralogy or porosity, or significant zones of slightly elevated pH values in the probe holes. The sediments do show …
Date: April 1, 2004
Creator: Serne, R JEFFREY.; Bjornstad, Bruce N.; Horton, Duane G.; Lanigan, David C.; Lindenmeier, Clark W.; Lindberg, Michael J. et al.
Object Type: Report
System: The UNT Digital Library
Direct measurement of the W boson decay width in proton-antiproton collisions at s**(1/2) = 1.96-TeV (open access)

Direct measurement of the W boson decay width in proton-antiproton collisions at s**(1/2) = 1.96-TeV

This dissertation describes a direct measurement of the W boson total decay width, {Lambda}{sub W}, using the D0 detector at the Fermilab Tevatron Collider. The measurement uses an integrated luminosity of 177.3 pb{sup -1} data, collected during the 2002-2003 run. The width is determined from the shape of the transverse mass distribution, M{sub T}, by fitting the data in the tail region 100 < M{sub T} < 200 GeV. The result if {Lambda}{sub W} = 2.011 {+-} 0.093(stat) {+-} 0.107(syst) GeV.
Date: October 1, 2004
Creator: Zhu, Jun-jie
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Sequencing Needs for Viral Diagnostics (open access)

Sequencing Needs for Viral Diagnostics

We built a system to guide decisions regarding the amount of genomic sequencing required to develop diagnostic DNA signatures, which are short sequences that are sufficient to uniquely identify a viral species. We used our existing DNA diagnostic signature prediction pipeline, which selects regions of a target species genome that are conserved among strains of the target (for reliability, to prevent false negatives) and unique relative to other species (for specificity, to avoid false positives). We performed simulations, based on existing sequence data, to assess the number of genome sequences of a target species and of close phylogenetic relatives (''near neighbors'') that are required to predict diagnostic signature regions that are conserved among strains of the target species and unique relative to other bacterial and viral species. For DNA viruses such as variola (smallpox), three target genomes provide sufficient guidance for selecting species-wide signatures. Three near neighbor genomes are critical for species specificity. In contrast, most RNA viruses require four target genomes and no near neighbor genomes, since lack of conservation among strains is more limiting than uniqueness. SARS and Ebola Zaire are exceptional, as additional target genomes currently do not improve predictions, but near neighbor sequences are urgently needed. …
Date: January 26, 2004
Creator: Gardner, S N; Lam, M; Mulakken, N J; Torres, C L; Smith, J R & Slezak, T
Object Type: Article
System: The UNT Digital Library
Search for CPT Violation with the FOCUS Experiment and Measurement of Lambda(b) lifetime in the decay Lambda(b) --> J / psi Lambda with the D0 Experiment (open access)

Search for CPT Violation with the FOCUS Experiment and Measurement of Lambda(b) lifetime in the decay Lambda(b) --> J / psi Lambda with the D0 Experiment

This dissertation describes two different projects from two different experiments. We have performed a search for CPT violation in neutral charm meson oscillations using data from the FOCUS Experiment. While flavor mixing in the charm sector is predicted to be small in the Standard Model, it is still possible to investigate CPT violation through a study of the proper time dependence of a CPT asymmetry in right-sign decay rates for D{sup 0} {yields} K{sup -} {pi}{sup +} and {bar D}{sup 0} {yields} K{sup +}{pi}{sup -}. This asymmetry is related to the CPT violating complex parameter {xi} and the mixing parameters x and y: A{sub CPT} {infinity} Re{xi}y - Im{xi}x. We determine a 95% confidence level limit of -0.0068 < Re{xi}y - Im{xi}x < 0.0234. Within the framework of the Standard Model Extension incorporating general CPT violation, we also find 95% confidence level limits for the expressions involving coefficients of Lorentz violation of (-2.8 < N(x,y,{delta}))({Delta}a{sub 0} + 0.6 {Delta}a{sub Z} < 4.8) x 10{sup -16} GeV, (-7.0 < N(x,y,{delta}){Delta}a{sub x} < 3.8) x 10{sup -16} GeV, and (-7.0 < N(x,y,{delta}){Delta}a{sub y} < 3.8) x 10{sup -16} GeV, where N(x,y,{delta}) is a normalization factor that incorporates mixing parameters x, y and …
Date: December 1, 2004
Creator: Kryemadhi, Abaz
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Structural properties of the geometrically frustrated pyrochlore Tb2Ti2O7 (open access)

Structural properties of the geometrically frustrated pyrochlore Tb2Ti2O7

Although materials that exhibit nearest-neighbor-only antiferromagnetic interactions and geometrical frustration theoretically should not magnetically order in the absence of disorder, few such systems have been observed experimentally. One such system appears to be the pyrochlore Tb{sub 2}Ti{sub 2}O{sub 7}. However, previous structural studies indicated that Tb{sub 2}Ti{sub 2}O{sub 7} is an imperfect pyrochlore. To clarify the situation, we performed neutron powder diffraction (NPD) and x-ray absorption fine structure (XAFS) measurements on samples that were prepared identically to those that show no magnetic order. The NPD measurements show that the long-range structure of Tb{sub 2}Ti{sub 2}O{sub 7} is well ordered with no structural transitions between 4.5 and 600 K. In particular, mean-squared displacements (u{sup 2}'s) for each site follow a Debye model with no offsets. No evidence for Tb/Ti site interchange was observed within an upper limit of 2%. Likewise, no excess or deficiency in the oxygen stoichiometry was observed, within an upper limit of 2% of the nominal pyrochlore value. Tb L{sub III} and Ti K-edge XAFS measurements from 20-300 K similarly indicate a well-ordered local structure. Other aspects of the structure are considered. We conclude that Tb{sub 2}Ti{sub 2}O{sub 7} has, within experimental error, an ideal, disorder-free pyrochlore lattice, …
Date: June 14, 2004
Creator: Han, Sang-Wook; Gardner, Jason S. & Booth, Corwin H.
Object Type: Article
System: The UNT Digital Library
Local indium segregation and band structure in high efficiencygreen light emitting InGaN/GaN diodes (open access)

Local indium segregation and band structure in high efficiencygreen light emitting InGaN/GaN diodes

GaN/InGaN light emitting diodes (LEDs) are commercialized for lighting applications because of the cost efficient way that they produce light of high brightness. Nevertheless, there is significant room for improving their external emission efficiency from typical values below 10 percent to more than 50 percent, which are obtainable by use of other materials systems that, however, do not cover the visible spectrum. In particular, green-light emitting diodes fall short in this respect, which is troublesome since the human eye is most sensitive in this spectral range. In this letter advanced electron microscopy is used to characterize indium segregation in InGaN quantum wells of high-brightness, green LEDs (with external quantum efficiency as high as 15 percent at 75 A/cm2). Our investigations reveal the presence of 1-3 nm wide indium rich clusters in these devices with indium concentrations as large as 0.30-0.40 that narrow the band gap locally to energies as small as 2.65 eV.
Date: November 23, 2004
Creator: Jinschek, Joerg R.; Erni, Rolf; Gardner, Nathan F.; Kim, AndrewY. & Kisielowski, Christian
Object Type: Article
System: The UNT Digital Library
Metastability and Delta-Phase Retention in Plutonium Alloys Final Report of LDRD Project 01-ERD-029 (open access)

Metastability and Delta-Phase Retention in Plutonium Alloys Final Report of LDRD Project 01-ERD-029

The {delta} to {alpha}' phase transformation in Pu-Ga alloys is intriguing for both scientific and technological reasons. On cooling, the ductile fcc {delta}-phase transforms martensitically to the brittle monoclinic {alpha}'-phase at approximately -120 C (depending on composition). This exothermic transformation involves a 20% volume contraction and a significant increase in resistivity. The reversion of {alpha}' to {delta} involves a large temperature hysteresis beginning just above room temperature. In an attempt to better understand the underlying thermodynamics and kinetics responsible for these unusual features, we have investigated the {delta} {leftrightarrow} {alpha}' phase transformations in a Pu-0.6 wt% Ga alloy using a combination of experimental and modeling techniques.
Date: February 11, 2004
Creator: Wong, J; Schwartz, A J; Blobaum, K M; Krenn, C R; Wall, M A; Wolfer, W G et al.
Object Type: Report
System: The UNT Digital Library
New Class of CW High-Power Diode-Pumped Alkali Lasers (DPALs) (open access)

New Class of CW High-Power Diode-Pumped Alkali Lasers (DPALs)

The new class of diode-pumped alkali vapor lasers (DPALs) offers high efficiency cw laser radiation at near-infrared wavelengths: cesium 895 nm, rubidium 795 nm, and potassium 770 nm. The working physical principles of DPALs will be presented. Initial 795 nm Rb and 895 nm Cs laser experiments performed using a titanium sapphire laser as a surrogate pump source demonstrated DPAL slope power conversion efficiencies in the 50-70% range, in excellent agreement with device models utilizing only literature spectroscopic and kinetic data. Using these benchmarked models for Rb and Cs, optimized DPALs with optical-optical efficiencies >60%, and electrical efficiencies of 25-30% are projected. DPAL device architectures for near-diffraction-limited power scaling into the high kilowatt power regime from a single aperture will be described. DPAL wavelengths of operation offer ideal matches to silicon and gallium arsenide based photovoltaic power conversion cells for efficient power beaming.
Date: March 23, 2004
Creator: Krupke, W F; Beach, R J; Kanz, V K; Payne, S A & Early, J T
Object Type: Article
System: The UNT Digital Library
A Multiplex PCR-coupled Liquid Bead Array for the Simultaneous Detection of Four Biothreat Agents (open access)

A Multiplex PCR-coupled Liquid Bead Array for the Simultaneous Detection of Four Biothreat Agents

We have developed a 10-plexed PCR assay coupled to a 12-plexed liquid bead array to rapidly screen environmental samples for B. anthracis, Y. pestis, F. tularensis, and B. melitensis. Highly validated species -specific primer sets were used to simultaneously amplify multiple diagnostic regions unique to each individual pathogen. Resolution of the mix of amplified products was achieved by PCR product hybridization to corresponding probe sequences, attached to unique sets of fluorescent beads. The hybridized beads were processed through a flow cytometer, which detected presence and quantity of each PCR product. The assay was optimized to allow for maximum sensitivity in a multiplexed format. A high- throughput demonstration was performed where 384 simulated environmental samples were spiked with different amounts of B. thuringensis spores and pathogen DNA. The samples were robotically processed to extract DNA and arrayed for multiplexed PCR-liquid bead detection. The assay correctly identified the presence or absence of each pathogen and collected over 3,000 individual data points within a single 8-hour shift for approximately $1.20 per sample in a 10-plexed assay.
Date: February 4, 2004
Creator: Wilson, W. J.; Erler, A. M.; Nasarabadi, S. L.; Skowronski, E. W. & McCready, P. M.
Object Type: Article
System: The UNT Digital Library
Science and Technology for Bioterrorism Defense (open access)

Science and Technology for Bioterrorism Defense

The Lawrence Livermore National Laboratory (LLNL) Chemical & Biological National Security Program (CBNP) provides science, technology, and integrated systems for chemical and biological security. Our approach is to develop and field systems that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons.
Date: May 4, 2004
Creator: Fitch, J P
Object Type: Article
System: The UNT Digital Library
Vadose Zone Hydrogeology Data Package for the 2004 Composite Analysis (open access)

Vadose Zone Hydrogeology Data Package for the 2004 Composite Analysis

This document describes the geologic framework, the physical, hydrologic, and contaminant transport properties of the geologic materials, and deep drainage (i.e. recharge) estimates. Much of the data and interpreted information were extracted from existing documents and databases.
Date: August 12, 2004
Creator: Last, George V.; Freeman, Eugene J.; Cantrell, Kirk J.; Fayer, Michael J.; Gee, Glendon W.; Nichols, William E. et al.
Object Type: Report
System: The UNT Digital Library
A GUIDE TO FUEL PERFORMANCE (open access)

A GUIDE TO FUEL PERFORMANCE

Heating oil, as its name implies, is intended for end use heating consumption as its primary application. But its identity in reference name and actual chemical properties may vary based on a number of factors. By name, heating oil is sometimes referred to as gas oil, diesel, No. 2 distillate (middle distillate), or light heating oil. Kerosene, also used as a burner fuel, is a No. 1 distillate. Due to the higher heat content and competitive price in most markets, No. 2 heating oil is primarily used in modern, pressure-atomized burners. Using No. 1 oil for heating has the advantages of better cold-flow properties, lower emissions, and better storage properties. Because it is not nearly as abundant in supply, it is often markedly more expensive than No. 2 heating oil. Given the advanced, low-firing rate burners in use today, the objective is for the fuel to be compatible and achieve combustion performance at the highest achievable efficiency of the heating systems--with minimal service requirements. Among the Oil heat industry's top priorities are improving reliability and reducing service costs associated with fuel performance. Poor fuel quality, fuel degradation, and contamination can cause burner shut-downs resulting in ''no-heat'' calls. Many of these …
Date: August 1, 2004
Creator: LITZKE,W.
Object Type: Report
System: The UNT Digital Library
The virtual organization membership service extention project (VOX) (open access)

The virtual organization membership service extention project (VOX)

Current grid development projects are being designed such that they require end users to be authenticated under the auspices of a ''recognized'' organization, called a Virtual Organization (VO). A VO must establish resource-usage agreements with grid resource providers. The VO is responsible for authorizing its members for grid computing privileges. The individual sites and resources typically enforce additional layers of authorization. The VOX project developed at Fermilab is an extension of VOMS, developed jointly for DataTAG by INFN and for DataGrid by CERN. The VOX project provides set of services that facilitate grid users registration with a VO, administration of VO members, as well as control access of grid users to a particular site. The current state of deployment and future steps to improve the prototype and implement some new features will be discussed.
Date: December 1, 2004
Creator: Levshina, T.; Bauderick, L.; Berman, E.; Fisk, I.; Graham, G.; Heavey, A. et al.
Object Type: Article
System: The UNT Digital Library
Drift Scale THM Model (open access)

Drift Scale THM Model

This model report documents the drift scale coupled thermal-hydrological-mechanical (THM) processes model development and presents simulations of the THM behavior in fractured rock close to emplacement drifts. The modeling and analyses are used to evaluate the impact of THM processes on permeability and flow in the near-field of the emplacement drifts. The results from this report are used to assess the importance of THM processes on seepage and support in the model reports ''Seepage Model for PA Including Drift Collapse'' and ''Abstraction of Drift Seepage'', and to support arguments for exclusion of features, events, and processes (FEPs) in the analysis reports ''Features, Events, and Processes in Unsaturated Zone Flow and Transport and Features, Events, and Processes: Disruptive Events''. The total system performance assessment (TSPA) calculations do not use any output from this report. Specifically, the coupled THM process model is applied to simulate the impact of THM processes on hydrologic properties (permeability and capillary strength) and flow in the near-field rock around a heat-releasing emplacement drift. The heat generated by the decay of radioactive waste results in elevated rock temperatures for thousands of years after waste emplacement. Depending on the thermal load, these temperatures are high enough to cause boiling …
Date: October 7, 2004
Creator: Rutqvist, J.
Object Type: Report
System: The UNT Digital Library
Uniform Beam Distributions at the Target of the NSRL Beam Transfer Line (open access)

Uniform Beam Distributions at the Target of the NSRL Beam Transfer Line

N/A
Date: July 1, 2004
Creator: Tsoupas, N.; Bellavia, S.; Bonati, R.; Brown, K.; Chiang, I-Hung; Gardner, C. J. et al.
Object Type: Report
System: The UNT Digital Library
Use of Electrochemical Noise to Assess Corrosion in Kraft Continuous Digesters (open access)

Use of Electrochemical Noise to Assess Corrosion in Kraft Continuous Digesters

Electrochemical noise (EN) probes were deployed in two continuous kraft digesters at a variety of locations representative of corrosion throughout the vessels. Current and potential noise, the temperature at each probe location, and the value of up to 60 process parameters (flow rates, liquor chemistry, etc.) were monitored continuously during each experiment. The results indicate that changes in furnish composition and process upsets were invariably associated with concurrent substantial changes in EN activity throughout the vessels. Post-test evaluation of the mild steel electrode materials in both vessels confirmed general corrosion of a magnitude consistent with historical trends in the respective vessels as well as values qualitatively (and semi-quantitatively) related to EN current sums for each electrode pair. Stainless steel electrodes representing 309LSi and 312 overlay repairs exhibited zero wastage corrosion--as did the actual overlays--but the EN data indicated periodic redox activity on the stainless steel that varied with time and position within the vessel. Little or no correlation between EN probe activity and other operational variables was observed in either vessel. Additional details for each digester experiment are summarized.
Date: November 29, 2004
Creator: Pawel, S.J.
Object Type: Report
System: The UNT Digital Library
Dispersion of waves in porous cylinders with patchy saturation Part I. Formulaton and torsional waves (open access)

Dispersion of waves in porous cylinders with patchy saturation Part I. Formulaton and torsional waves

Laboratory experiments on wave propagation through saturated and partially saturated porous media have often been conducted on porous cylinders that were initially fully saturated and then allowed to dry while continuing to acquire data on the wave behavior. Since it is known that drying typically progresses from outside to inside, a sensible physical model of this process is concentric cylinders having different saturation levels--the simplest example being a fully dry outer cylindrical shell together with a fully wet inner cylinder. We use this model to formulate the equations for wave dispersion in porous cylinders for patchy saturation (i.e. drainage) conditions. In addition to multiple modes of propagation obtained numerically from these dispersion relations, we find two distinct analytical expressions for torsional wave modes. We solve the dispersion relation for torsional waves for two examples: Massillon sandstone and Sierra White granite. The drainage analysis appears to give improved agreement with the data for both these materials.
Date: July 28, 2004
Creator: Berryman, J G & Pride, S R
Object Type: Article
System: The UNT Digital Library
Ponderomotive Barrier as a Maxwell Demon (open access)

Ponderomotive Barrier as a Maxwell Demon

The possibility of efficient ponderomotive current drive in a magnetized plasma was reported recently in [Phys. Rev. Lett. 91, 205004 (2003)]. Precise limitations on the efficiency are now given through a comprehensive analytical and numerical study of single-particle dynamics under the action of a cyclotron-resonant rf drive in various field configurations. Expressions for the particle energy gain and acceleration along the dc magnetic field are obtained. The fundamental correlation between the two effects is described. A second fundamental quantity, namely the ratio of the potential barrier to the energy gain, can be changed by altering the field configuration. The asymmetric ponderomotive current drive effect can be optimized by minimizing the transverse heating.
Date: May 4, 2004
Creator: Dodin, I. Y.; Fisch, N. J. & Rax, J. M.
Object Type: Report
System: The UNT Digital Library
Development of Novel Water-Gas Shift Membrane Reactor (open access)

Development of Novel Water-Gas Shift Membrane Reactor

None
Date: December 29, 2004
Creator: Ho, W. S. Winston
Object Type: Report
System: The UNT Digital Library