Isopiestic Determination of the Osmotic and Activity Coefficients of NaCl + SrCl2 + H2O at 298.15 K, and Representation with an Extended Ion-Interaction Model (open access)

Isopiestic Determination of the Osmotic and Activity Coefficients of NaCl + SrCl2 + H2O at 298.15 K, and Representation with an Extended Ion-Interaction Model

Isopiestic vapor-pressure measurements were made at 298.15 K for aqueous NaCl + SrCl{sub 2} solutions, using NaCl(aq) as the reference standard. The measurements for these ternary solutions were made at NaCl ionic strength fractions of y{sub 1} = 0.17066, 0.47366, and 0.82682 for the water activity range 0.9835 {ge} a{sub w} {ge} 0.8710. Our results, and those from two previous isopiestic studies, were combined and used with previously determined parameters for NaCl(aq) and those for SrCl{sub 2}(aq) determined here to evaluate the mixing parameters{sup S}{Theta}{sub Na,Sr} = (0.0562 {+-} 0.0007) kg {center_dot} mol{sup -1} and {Psi}{sub Na,Sr,Cl} = -(0.00705 {+-} 0.00017) kg{sup 2} {center_dot} mol{sup -2} for an extended form of Pitzer's ion-interaction model. These model parameters are valid for ionic strengths of I {le} 7.0 mol {center_dot} kg{sup -1}, where higher-order electrostatic effects have been included in the mixture model. If the fitting range is extended to the saturated solution molalities, then {sup S}{Theta}{sub Na,Sr} = (0.07885 {+-} 0.00195) kg {center_dot} mol{sup -1} and {Psi}{sub Na,Sr,Cl} = -(0.01230 {+-} 0.00033) kg{sup 2} {center_dot} mol{sup -2}. The extended ion-interaction model parameters obtained from available isopiestic data for SrCl{sub 2}(aq) at 298.15 K yield recommended values of the water activities and …
Date: November 9, 2004
Creator: Clegg, S. L.; Rard, J. A. & Miller, D. G.
Object Type: Article
System: The UNT Digital Library
2004 LLNL Computational Chemistry and Materials Science Summer Institute (open access)

2004 LLNL Computational Chemistry and Materials Science Summer Institute

None
Date: November 9, 2004
Creator: Rudd, Robert E. & McElfresh, Michael
Object Type: Report
System: The UNT Digital Library
Interfacial Control of Deformation Twinning in Creep-Deformed TiAl/Ti3Al Nanolaminate (open access)

Interfacial Control of Deformation Twinning in Creep-Deformed TiAl/Ti3Al Nanolaminate

None
Date: November 9, 2004
Creator: Hsiung, L
Object Type: Report
System: The UNT Digital Library
Environmentally Assisted Cracking of Commercial Ni-Cr-Mo Alloys - A Review (open access)

Environmentally Assisted Cracking of Commercial Ni-Cr-Mo Alloys - A Review

Nickel-Chromium-Molybdenum alloys (Ni-Cr-Mo) are highly resistant to general corrosion, localized corrosion and environmentally assisted cracking (EAC). Cr acts as a beneficial element under oxidizing acidic conditions and Mo under reducing conditions. All three elements (Ni, Cr and Mo) act synergistically to provide resistance to EAC in environments such as hot concentrated chloride solutions. Ni-Cr-Mo alloys may suffer EAC in environments such as hot caustic solutions, hot wet hydrofluoric acid (HF) solutions and in super critical water oxidation (SCWO) applications. Not all the Ni-Cr-Mo alloys have the same susceptibility to cracking in the mentioned environments. Most of the available data regarding EAC is for the oldest Ni-Cr-Mo alloys such as N10276 and N06625.
Date: November 9, 2004
Creator: Rebak, R B
Object Type: Article
System: The UNT Digital Library
Component Technology for High-Performance Scientific Simulation Software (open access)

Component Technology for High-Performance Scientific Simulation Software

We are developing scientific software component technology to manage the complexity of modem, parallel simulation software and increase the interoperability and re-use of scientific software packages. In this paper, we describe a language interoperability tool named Babel that enables the creation and distribution of language-independent software libraries using interface definition language (IDL) techniques. We have created a scientific IDL that focuses on the unique interface description needs of scientific codes, such as complex numbers, dense multidimensional arrays, complicated data types, and parallelism. Preliminary results indicate that in addition to language interoperability, this approach provides useful tools for thinking about the design of modem object-oriented scientific software libraries. Finally, we also describe a web-based component repository called Alexandria that facilitates the distribution, documentation, and re-use of scientific components and libraries.
Date: November 9, 2000
Creator: Epperly, T; Kohn, S & Kumfert, G
Object Type: Article
System: The UNT Digital Library
Formation of Carbon Nanostructures in Cobalt- and Nickel-Doped Carbon Aerogels (open access)

Formation of Carbon Nanostructures in Cobalt- and Nickel-Doped Carbon Aerogels

We have prepared carbon aerogels (CAs) doped with cobalt or nickel through sol-gel polymerization of formaldehyde with the potassium salt of 2,4-dihydroxybenzoic acid, followed by ion-exchange with M(NO{sub 3}){sub 2} (where M = Co{sup 2+} or Ni{sup 2+}), supercritical drying with liquid CO{sub 2} and carbonization at temperatures between 400 C and 1050 C under an N{sub 2} atmosphere. The nanostructures of these metal-doped carbon aerogels were characterized by elemental analysis, nitrogen adsorption, high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Metallic nickel and cobalt nanoparticles are generated during the carbonization process at about 400 C and 450 C, respectively, forming nanoparticles that are {approx}4 nm in diameter. The sizes and size dispersion of the metal particles increase with increasing carbonization temperatures for both materials. The carbon frameworks of the Ni- and Co-doped aerogels carbonized below 600 C mainly consist of interconnected carbon particles with a size of 15 to 30 nm. When the samples are pyrolyzed at 1050 C, the growth of graphitic nanoribbons with different curvatures is observed in the Ni and Co-doped carbon aerogel materials. The distance of graphite layers in the nanoribbons is about 0.38 nm. These metal-doped CAs retain …
Date: November 9, 2004
Creator: Fu, R.; Baumann, T. F.; Cronin, S.; Dresselhaus, G.; Dresselhaus, M. & Satcher, J. H. Jr.
Object Type: Article
System: The UNT Digital Library
Creation and Plan of an Underground Geologic Radioactive Waste Isolation Facility at the Nizhnekansky Rock Massif in Russia (open access)

Creation and Plan of an Underground Geologic Radioactive Waste Isolation Facility at the Nizhnekansky Rock Massif in Russia

This joint geologic repository project in Russia was initiated in May 2002 between the United States (U.S.) International Science and Technology Center (ISTC) and the Federal State Unitary Enterprise ''All-Russian Research and Design Institute of Production Engineering'' (VNIPIPT). The project (ISTC Partner Project 2377) is funded by the U.S. Department of Energy Office of Civilian Radioactive Waste Management (DOE-RW) for a period of 2-1/2 years. ISTC project activities were integrated into other ongoing geologic repository site characterization activities near the Mining and Chemical Combine (MCC K-26) site. This allowed the more rapid development of a plan for an underground research laboratory, including underground design and layouts. It will not be possible to make a final choice between the extensively studied Verkhne-Itatski site or the Yeniseiski site for construction of the underground laboratory during the project time frame because additional data are needed. Several new sources of data will become available in the next few years to help select a final site. Studies will be conducted at the 1-km deep borehole at the Yeniseisky site where drilling started in 2004. And in 2007, after the scheduled shutdown of the last operating reactor at the MCC K-26 site, data will be collected …
Date: November 9, 2004
Creator: Gupalo, T A; Kudinov, K G; Jardine, L J & Williams, J
Object Type: Article
System: The UNT Digital Library
The Nature of Emission from Optical Breakdown Induced by Pulses of fs and ns Duration (open access)

The Nature of Emission from Optical Breakdown Induced by Pulses of fs and ns Duration

Spectral emission from optical breakdown in the bulk of a transparent dielectric contains information about the nature of the breakdown medium. We have made time resolved measurements of the breakdown induced emission caused by nanosecond and femtosecond infrared laser pulses. We previously demonstrated that the emission due to ns pulses is blackbody in nature allowing determination of the fireball temperature and pressure during and after the damage event. The emission due to femtosecond pulse breakdown is not blackbody in nature; two different spectral distributions being noted. In one case, the peak spectral distribution occurs at the second harmonic of the incident radiation, in the other the distribution is broader and flatter and presumably due to continuum generation. The differences between ns and fs breakdown emission can be explained by the differing breakdown region geometries for the two pulse durations. The possibility to use spectral emission as a diagnostic of the emission region morphology will be discussed.
Date: November 9, 2004
Creator: Carr, C W; Feit, M D; Rubenchik, A M; Demange, P; Kucheyev, S; Shirk, M D et al.
Object Type: Article
System: The UNT Digital Library
Simulation of Spheromak Evolution and Energy Confinement (open access)

Simulation of Spheromak Evolution and Energy Confinement

Simulation results are presented that illustrate the formation and decay of a spheromak plasma driven by a coaxial electrostatic plasma gun, and that model the energy confinement of the plasma. The physics of magnetic reconnection during spheromak formation is also illuminated. The simulations are performed with the three-dimensional, time-dependent, resistive magnetohydrodynamic NIMROD code. The simulation results are compared to data from the SSPX spheromak experiment at the Lawrence Livermore National Laboratory. The simulation results are tracking the experiment with increasing fidelity (e.g., improved agreement with measurements of the magnetic field, fluctuation amplitudes, and electron temperature) as the simulation has been improved in its representations of the geometry of the experiment (plasma gun and flux conserver), the magnetic bias coils, and the detailed time dependence of the current source driving the plasma gun, and uses realistic parameters. The simulations are providing a better understanding of the dominant physics in SSPX, including when the flux surfaces close and the mechanisms limiting the efficiency of electrostatic drive.
Date: November 9, 2004
Creator: Cohen, B; Hooper, E; Cohen, R; Hill, D; McLean, H; Wood, R et al.
Object Type: Article
System: The UNT Digital Library
New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis (open access)

New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis

We review the current status of the nuclear reaction rates needed to study nucleosynthesis in massive stars. Results for the calculated nucleosynthesis of all stable species from Hydrogen to Bismuth in a completely evolved 25 M{sub {circle_dot}} star of initial solar metallicity will be presented. Special emphasis will be paid to two particular reactions, {sup 12}C({alpha}, {gamma}){sup 16}O and {sup 22}Ne({alpha},n){sup 25}Mg, and their effect on the structure of the star and resultant nucleosynthesis. Both have been measured many times, but the present range of experimental uncertainty translates into remarkable sensitivity of the calculated nucleosynthesis.
Date: November 9, 2001
Creator: Hoffman, R; Rauscher, T; Heger, A & Woosley, S
Object Type: Article
System: The UNT Digital Library
DPB progress report: Hydrogen uptake capacity for a particular sample of DPB (open access)

DPB progress report: Hydrogen uptake capacity for a particular sample of DPB

The authors have performed hydrogen uptake to measure the remaining capacity for two DPB pellet samples. The measurements were made with a Cahn microbalance operating at room temperature. The DPB samples were placed inside a quartz boat and the microbalance was then evacuated to a base pressure of 10{sup -4} Torr overnight. This overnight pumping removed volatile contaminants from the DPB pellets prior to the introduction of 600 Torr of N{sub 2} into the microbalance chamber. Next, a leak valve connecting the microbalance with a research grade source of H{sub 2} was opened to add 100 Torr of H{sub 2} on top of the 600 Torr of N{sub 2} already in the microbalance. When the total pressure in the microbalance reached 700 Torr, the H{sub 2} leak valve was not completely shut off but reduced to a very small positive rate. An automatic gate valve connecting the microbalance to a turbo molecular pump was programmed by a controller to keep the total pressure in the microbalance at 700 {+-} 3 Torr. The balance between H{sub 2} consumption due to DPB uptake and H{sub 2} leak rate into the microbalance was such that the gate valve to the turbo molecular pump …
Date: November 9, 2004
Creator: Dinh, L. N.; Schildbach, M. A.; Maxwell, R. S.; Balazs, B. & McLean, W., II
Object Type: Report
System: The UNT Digital Library
H2O Outgassing from Silicones (open access)

H2O Outgassing from Silicones

In this fiscal year, we have tested the H{sub 2}O outgassing model for TR55 against independent core tests performed at different temperatures by our collaborators at Y12. At higher temperature ({approx} 71 C), the model properly predicts moisture outgassing from TR55 over the entire experiment. At lower temperature ({approx} 42.5 C), the model correctly predicts long-term moisture outgassing. However, in short-term limit, a better fit with core tests might be expected when the diffusion effect of H{sub 2}O through the silicone matrix is included into the model in the near future. A lookup table for the moisture content as well as moisture outgassing kinetics for M9787 which have previously been heated to 460K for one day and then exposed to relevant low levels of moisture is also now available as a reference for engineers/technicians in the fields.
Date: November 9, 2004
Creator: Dinh, L. N.; Maxwell, R. S.; Schildbach, M. A.; Balazs, B. & McLean, W., II
Object Type: Report
System: The UNT Digital Library
Comparisons of Line Emission from ICF Capsules in 2- and 3-Dimensional Simulations (open access)

Comparisons of Line Emission from ICF Capsules in 2- and 3-Dimensional Simulations

Hydrodynamic instabilities reduce the yield in inertial confinement fusion (ICF) implosions. Line emission from dopants placed in the capsule can be used to diagnose the extent of the instabilities. This paper presents the results of a large number of 2D simulations and a few 3D simulations of line emission from argon in the DH fuel and titanium placed in the inner layers of the plastic shell of a NOVA ICF capsule. The Simulations have been compared to NOVA experimental data on the ratio of argon Ly-{beta} to titanium He-{alpha}, the relative strength of titanium He-{alpha} and its satellites, and the strength of the continuum near titanium He-{alpha}. The simulations are in reasonable agreement with the data, but the amount of data is small enough that it is hard to make precise comparisons. Two different atomic databases have been used in a first attempt to determine the set of configurations required to properly model the titanium emission.
Date: November 9, 2002
Creator: Langer, S. H.; Scott, H. A.; Marinak, M. M. & Landen, O. L.
Object Type: Article
System: The UNT Digital Library
Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles: SERDP Final Report 9/00 (open access)

Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles: SERDP Final Report 9/00

Enzymes for Degradation of Energetic Materials and Demilitarization of Explosives Stockpiles: SERDP Final Report 9/00
Date: November 9, 2000
Creator: Goheen, Steven C.; Campbell, James A.; Shi, Ying & Aust, Steve
Object Type: Report
System: The UNT Digital Library
Form CJ-7, Annual Parole Survey: 2005 (open access)

Form CJ-7, Annual Parole Survey: 2005

Blank parole data survey containing a series of questions related to the parole population in a particular location, with instructions for filling out the survey.
Date: November 9, 2005
Creator: United States. Bureau of Justice Statistics.
Object Type: Text
System: The UNT Digital Library
Form CJ-8, Annual Probation Survey: 2005 (open access)

Form CJ-8, Annual Probation Survey: 2005

Blank probation data survey containing a series of questions related to the probationary population in a particular location, with instructions for filling out the survey.
Date: November 9, 2005
Creator: United States. Bureau of Justice Statistics.
Object Type: Text
System: The UNT Digital Library
Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides (open access)

Strategic Design and Optimization of Inorganic Sorbents for Cesium, Strontium and Actinides

The primary objective of the Notre Dame component of the project was computational in nature. The goal was to provide a design tool for the synthesis of optimized sorbents for the removal of cesium, strontium and actinides from nuclear waste solutions. Molecular modeling enables us to observe and better understand the molecular level interactions that govern the selectivity of specific radionuclides in a particular sorbent. The research focused on the development and validation of a suitable and transferable model for all the cations and ion exchangers of interest, nd then subsequent simulations which determined the siting and mobility of water and cations. Speciic accomplishments include: (1) improving existing intermolecular force fields to accurately model the sorbents of interest; (2) utilizing energy-minimizations and molecular dynamics simulations for structural prediction of CST and niobium-substituted CST materials; (3) determining Na+/water positions in polyoxoniobate materials using molecular dynamics simulations; and (4) developing Hybrid Monte Carlo methods for improved structural prediction.
Date: November 9, 2009
Creator: Maginn, Edward J.
Object Type: Report
System: The UNT Digital Library
QCD Spin Physics: Theoretical Overview (open access)

QCD Spin Physics: Theoretical Overview

We give an overview of some of the current activities and results in QCD spin physics. We focus on the helicity structure of the nucleon, where we highlight the results of a recent first global analysis of the helicity parton distributions, and on single-transverse spin asymmetries.
Date: November 9, 2008
Creator: Vogelsang, W.
Object Type: Article
System: The UNT Digital Library
Scaling behavior of individual barkhausen avalanches in nucleation-mediated magnetization reversal processes (open access)

Scaling behavior of individual barkhausen avalanches in nucleation-mediated magnetization reversal processes

We report the scaling behavior of Barkhausen avalanches along the hysteresis loop of a CoCrPt alloy film with perpendicular magnetic anisotropy for every field step of 200 Oe. Individual Barkhausen avalanches are directly observed via high-resolution soft X-ray microscopy with a spatial resolution of 15 nm. The Barkhausen avalanches exhibit a power-law scaling behavior, where the scaling exponent of the power-law distribution drastically changes from 1 {+-} 0.04 to 1.47 {+-} 0.03 as the applied magnetic field approaches the coercivity of the CoCrPt film. We infer that this is due to the coupling of adjacent domains.
Date: November 9, 2009
Creator: Im, Mi-Young; Fischer, Peter; Kim, Dong-Hyun & Shin, Sung-Chul
Object Type: Article
System: The UNT Digital Library
RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY SOIL SAMPLES (open access)

RAPID SEPARATION METHOD FOR ACTINIDES IN EMERGENCY SOIL SAMPLES

A new rapid method for the determination of actinides in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for samples up to 2 grams in emergency response situations. The actinides in soil method utilizes a rapid sodium hydroxide fusion method, a lanthanum fluoride soil matrix removal step, and a streamlined column separation process with stacked TEVA, TRU and DGA Resin cartridges. Lanthanum was separated rapidly and effectively from Am and Cm on DGA Resin. Vacuum box technology and rapid flow rates are used to reduce analytical time. Alpha sources are prepared using cerium fluoride microprecipitation for counting by alpha spectrometry. The method showed high chemical recoveries and effective removal of interferences. This new procedure was applied to emergency soil samples received in the NRIP Emergency Response exercise administered by the National Institute for Standards and Technology (NIST) in April, 2009. The actinides in soil results were reported within 4-5 hours with excellent quality.
Date: November 9, 2009
Creator: Maxwell, S.; Culligan, B. & Noyes, G.
Object Type: Article
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
Relating the Proca Photon Mass and the Cosmic Vector Potential via Solar Wind (open access)

Relating the Proca Photon Mass and the Cosmic Vector Potential via Solar Wind

None
Date: November 9, 2009
Creator: Ryutov, D. D.
Object Type: Article
System: The UNT Digital Library
VAPOR SPACE AND LIQUID/AIR INTERFACECORROSION TESTS (open access)

VAPOR SPACE AND LIQUID/AIR INTERFACECORROSION TESTS

The phenomena of vapor space corrosion and liquid/air interface corrosion of carbon steel in simulated liquid waste environments have been investigated. Initial experiments have explored the hypothesis that vapor space corrosion may be accelerated by the formation of a corrosive electrolyte on the tank wall by a process of evaporation of relatively warmer waste and condensation of the vapor on the relatively cooler tank wall. Results from initial testing do not support the hypothesis of electrolyte transport by evaporation and condensation. The analysis of the condensate collected by a steel specimen suspended over a 40 C simulated waste solution showed no measurable concentrations of the constituents of the simulated solution and a decrease in pH from 14 in the simulant to 5.3 in the condensate. Liquid/air interface corrosion was studied as a galvanic corrosion system, where steel at the interface undergoes accelerated corrosion while steel in contact with bulk waste is protected. The zero-resistance-ammeter technique was used to measure the current flow between steel specimens immersed in solutions simulating (1) the high-pH bulk liquid waste and (2) the expected low-pH meniscus liquid at the liquid/air interface. Open-circuit potential measurements of the steel specimens were not significantly different in the two …
Date: November 9, 2009
Creator: Zapp, P. & Hoffman, E.
Object Type: Report
System: The UNT Digital Library
Lateral Gene Transfer Among Subsurface Bacteria‭: ‬Horizontal Gene Flow in Microbial Communities‭: ‬A Special Focus issue‭, ‬Web Focus and Supplement (open access)

Lateral Gene Transfer Among Subsurface Bacteria‭: ‬Horizontal Gene Flow in Microbial Communities‭: ‬A Special Focus issue‭, ‬Web Focus and Supplement

A final report - publication of the results from a workshop held in June 2004 on Horizontal Gene Transfer in the Enviornment
Date: November 9, 2009
Creator: Barkay, Tamar
Object Type: Text
System: The UNT Digital Library