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CO Adsorption on Noble Metal Clusters: Local Environment Effects (open access)

CO Adsorption on Noble Metal Clusters: Local Environment Effects

Article on CO adsorption on noble metal clusters and local environmental effects.
Date: March 7, 2011
Creator: Buongiorno Nardelli, Marco; Morrow, Brian H.; Resasco, Daniel E. & Striolo, Alberto
System: The UNT Digital Library
Comments on "Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra" (open access)

Comments on "Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra"

Article commenting on "Role of Anions (tetrafluoroborate, perchlorate) of tetrabutylammonium salts in determining solvation effects prevailing in industrially essential solvents probed by conductance and FT-IR spectra.
Date: March 7, 2014
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Comment on "Measurement and Correlation of Solubilities of (Z)-2-(2-Aminothiazol-4-yl)-2-methoxyiminoacetic Acid in Different Pure Solvents and Binary Mixtures of Water + (Ethanol, Methanol, or Glycol)" (open access)

Comment on "Measurement and Correlation of Solubilities of (Z)-2-(2-Aminothiazol-4-yl)-2-methoxyiminoacetic Acid in Different Pure Solvents and Binary Mixtures of Water + (Ethanol, Methanol, or Glycol)"

Article commenting on an article titled, "Measurement and correlation of solubilities of (Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid in different pure solvents and binary mixtures of water + (ethanol, methanol, or glycol)," published in March 2011.
Date: March 7, 2012
Creator: Jouyban, Abolghasem; Fakhree, Mohammad Amin Abolghassemi & Acree, William E. (William Eugene)
System: The UNT Digital Library
Sensor fusion and nonlinear prediction for anomalous event detection (open access)

Sensor fusion and nonlinear prediction for anomalous event detection

The authors consider the problem of using the information from various time series, each one characterizing a different physical quantity, to predict the future state of the system and, based on that information, to detect and classify anomalous events. They stress the application of principal components analysis (PCA) to analyze and combine data from different sensors. They construct both linear and nonlinear predictors. In particular, for linear prediction the authors use the least-mean-square (LMS) algorithm and for nonlinear prediction they use both backpropagation (BP) networks and fuzzy predictors (FP). As an application, they consider the prediction of gamma counts from past values of electron and gamma counts recorded by the instruments of a high altitude satellite.
Date: March 7, 1995
Creator: Hernandez, J. V.; Moore, K. R. & Elphic, R. C.
System: The UNT Digital Library
Simulations of laser-initiated stress waves (open access)

Simulations of laser-initiated stress waves

We present a study of the short-time scale (< 250 ns) fluid dynamic response of water to a fiber-delivered laser pulse of variable energy and spatial profile. The laser pulse was deposited on a stress confinement time scale. The spatial profile was determined by the fiber core radius r (110 and 500 microns) and the water absorption coefficient {mu}{sub 2} (200 and 50 l/cm). Considering 2D cylindrical symmetry, the combination of fiber radius and absorption coefficient parameters can be characterized as near planar (1{mu}{sub 2} greater than r), symmetric (1/{mu}{sub 2}=r), and side-directed (1/{mu}{sub 2} less than r). The spatial profile study shows how the stress wave various as a function of geometry. For example, relatively small absorption coefficients can result in side-propagating shear and tensile fields.
Date: March 7, 1997
Creator: Maitland, D. J.; Celliers, P.; Amendt, P.; Da Silva, L.; London, R. A.; Matthews, D. et al.
System: The UNT Digital Library
Experimental study of sin 2 {beta} and sin 2 {alpha} (open access)

Experimental study of sin 2 {beta} and sin 2 {alpha}

Detailed measurements of CP violation in B meson decay are on the horizon. Here the author reviews the status of current measurements of sin 2{beta} made at LEP and CDF. These yield an average of sin 2{beta} = 0.82 {+-} 0.39, giving 97% confidence that {beta} is greater than 0, evidence that CP violation occurs in B decay. He reviews predictions for the precision one can expect on sin 2{beta} and sin 2{alpha} in the next few years.
Date: March 7, 2000
Creator: Truschuk, W.
System: The UNT Digital Library
Two target height effects on interferometric synthetic aperture radar coherence (open access)

Two target height effects on interferometric synthetic aperture radar coherence

Useful products generated from interferometric synthetic aperture radar (IFSAR) complex data include height measurement, coherent change detection, and classification. The IFSAR coherence is a spatial measure of complex correlation between two collects, a product of IFSAR signal processing. A tacit assumption in such IFSAR signal processing is that one height target exists in each range-Doppler cell. This paper presents simulations of IFSAR coherence if two targets with different heights exist in a given range-Doppler cell, a condition in IFSAR collections produced by layover. It also includes airborne IFSAR data confirming the simulation results. The paper concludes by exploring the implications of the results on IFSAR classification and height measurements.
Date: March 7, 2000
Creator: Yocky, David A. & Jakowatz Jr.,CHARLES V.
System: The UNT Digital Library
A 3.3 MJ, Rb + 1 driver design based on an integrated systems analysis (open access)

A 3.3 MJ, Rb + 1 driver design based on an integrated systems analysis

A computer model for systems analysis of heavy ion drivers has been developed and used to evaluate driver designs for inertial fusion energy (IFE). The present work examines a driver for a close-coupled target design that requires less total beam energy but also smaller beam spots sizes than previous target designs. Design parameters and a cost estimate for a 160 beam, 3.3 MJ driver using rubidium ions (A = 85) are reported, and the sensitivity of the results to variations in selected design parameters is given.
Date: March 7, 2000
Creator: Meier, W. R.; Barnard, J. J. & Bangerter, R. O.
System: The UNT Digital Library
Hadron Collider Detectors (open access)

Hadron Collider Detectors

Experiments are being prepared at the Fermilab Tevatron and the CERN Large Hadron Collider that promise to deliver extraordinary insights into the nature of spontaneous symmetry breaking, and the role of supersymmetry in the universe. This article reviews the goals, challenges, and designs of these experiments. The first hadron collider, the ISR at CERN, has to overcome two initial obstacles. The first was low luminosity, which steadily improved over time. The second was the broad angular spread of interesting events. In this regard Maurice Jacob noted (1): The answer is ... sophisticated detectors covering at least the whole central region (45{degree} {le} {theta} {le} 135{degree}) and full azimuth. This statement, while obvious today, reflects the major revelation of the ISR period that hadrons have partonic substructure. The result was an unexpectedly strong hadronic yield at large transverse momentum (p{sub T}). Partly because of this, the ISR missed the discovery of the J/{psi} and later missed the {Upsilon}. The ISR era was therefore somewhat less auspicious than it might have been. It did however make important contributions in areas such as jet production and charm excitation and it paved the way for the SPS collider, also at CERN.
Date: March 7, 2000
Creator: Incandela, J.R.
System: The UNT Digital Library
Dedicated OO expertise applied to Run II software projects (open access)

Dedicated OO expertise applied to Run II software projects

The change in software language and methodology by CDF and D0 to object-oriented from procedural Fortran is significant. Both experiments requested dedicated expertise that could be applied to software design, coding, advice and review. The Fermilab Run II offline computing outside review panel agreed strongly with the request and recommended that the Fermilab Computing Division hire dedicated OO expertise for the CDF/D0/Computing Division joint project effort. This was done and the two experts have been an invaluable addition to the CDF and D0 upgrade software projects and to the Computing Division in general. These experts have encouraged common approaches and increased the overall quality of the upgrade software. Advice on OO techniques and specific advice on C++ coding has been used. Recently a set of software reviews has been accomplished. This has been a very successful instance of a targeted application of computing expertise, and constitutes a very interesting study of how to move toward modern computing methodologies in HEP.
Date: March 7, 2000
Creator: Amidei, D.
System: The UNT Digital Library
Role of Fusion Energy in a Sustainable Global Energy Strategy (open access)

Role of Fusion Energy in a Sustainable Global Energy Strategy

Fusion can play an important role in sustainable global energy because it has an available and unlimited fuel supply and location not restricted by climate or geography. Further, it emits no greenhouse gases. It has no potential for large energy releases in an accident, and no need for more than about 100 years retention for radioactive waste disposal. Substantial progress in the realization of fusion energy has been made during the past 20 years of research. It is now possible to produce significant amounts of energy from controlled deuterium and tritium (DT) reactions in the laboratory. This has led to a growing confidence in our ability to produce burning plasmas with significant energy gain in the next generation of fusion experiments. As success in fusion facilities has underpinned the scientific feasibility of fusion, the high cost of next-step fusion facilities has led to a shift in the focus of international fusion research towards a lower cost development path and an attractive end product. The increasing data base from fusion research allows conceptual fusion power plant studies, of both magnetic and inertial confinement approaches to fusion, to translate commercial requirements into the design features that must be met if fusion is …
Date: March 7, 2001
Creator: Sheffield, J.
System: The UNT Digital Library
Computer-aided analysis of eddy current rotating probe data. (open access)

Computer-aided analysis of eddy current rotating probe data.

Eddy current (EC) estimate of flaw size obtained from inservice inspection is often the primary means of assessing the structural integrity of steam generator tubes. Reliable prediction of failure pressure and leak rate in tubes with complex cracking requires more detailed information about the geometry and extent of degradation than is generally available from conventional bobbin coil examinations. High-resolution inspections with EC rotating probes are thus carried out on selected regions of tubing to provide the more extensive nondestructive evaluation (NDE) information that is needed to better assess flaw size and distribution. Interpretation of signals from complex cracking that are often distorted by coherent and incoherent noise can be a challenging NDE task. Studies at Argonne National Laboratory have demonstrated that computer-aided data analysis can be used for more accurate and efficient processing of the large amounts of data collected by such probes. The basic structure of a rule-based multiparameter data analysis algorithm is described in this paper. Multiple-frequency inspection data from a standard rotating pancake coil were used for the analyses. The codes were implemented as MATLAB scripts and provide, as the final outcome, profiles of flaw depth in a section of tube. Graphical user interface tools were devised …
Date: March 7, 2002
Creator: Bakhtiari, S.; Park, J. Y.; Kupperman, D. S. & Shack, W. J.
System: The UNT Digital Library
Plutonium Disposition by Immobilization (open access)

Plutonium Disposition by Immobilization

The ultimate goal of the Department of Energy (DOE) Immobilization Project is to develop, construct, and operate facilities that will immobilize between 17 to 50 tonnes (MT) of U.S. surplus weapons-usable plutonium materials in waste forms that meet the ''spent fuel'' standard and are acceptable for disposal in a geologic repository. Using the ceramic can-in-canister technology selected for immobilization, surplus plutonium materials will be chemically combined into ceramic forms which will be encapsulated within large canisters of high level waste (HLW) glass. Deployment of the immobilization capability should occur by 2008 and be completed within 10 years. In support of this goal, the DOE Office of Fissile Materials Disposition (MD) is conducting development and testing (D&amp;T) activities at four DOE laboratories under the technical leadership of Lawrence Livermore National Laboratory (LLNL). The Savannah River Site has been selected as the site for the planned Plutonium Immobilization Plant (PIP). The D&amp;T effort, now in its third year, will establish the technical bases for the design, construction, and operation of the U. S. capability to immobilize surplus plutonium in a suitable and cost-effective manner. Based on the D&amp;T effort and on the development of a conceptual design of the PIP, automation is …
Date: March 7, 2000
Creator: Gould, T.; DiSabatino, A. & Mitchell, M.
System: The UNT Digital Library
High Energy Gamma Rays from p+X, X=Cu, Ag, Au at 34 MeV (open access)

High Energy Gamma Rays from p+X, X=Cu, Ag, Au at 34 MeV

In this paper we present results from the measurement of the gamma ray yield in the reaction of 34-MeV protons on Cu, Ag and Au. The protons were produced by the University of Washington superconducting linac. The gamma rays were measured using a large NaI and two large BaF{sub 2} detectors. Angular distributions were obtained for each of the three targets. Data for the Cu and Ag target were taken at six lab angles between 35 and 135 degrees, while data were taken at eight lab angles between 35 and 135 degrees for the Au target. The data were compared to several models. These included Hauser-Feshbach and direct-semidirect (DSD) calculations. We also compared the measurements to proton-nucleus bremsstrahlung calculations. The bremsstrahlung calculations greatly underpredicted the cross section and produced an angular distribution which was too flat. The Hauser-Feshbach calculations reproduced the yield of the softer portion of the spectrum reasonably well for all three targets. The DSD calculations reproduced the yield and angular distributions quite well for energies above about 20 MeV. However, the yields were underpredicted in the 15-18 MeV region, which suggests that multistep mechanisms may be needed for this target.
Date: March 7, 2000
Creator: Luke, S. J.; Dietrich, F. S.; Chadwick, M. B.; Gossett, C. A.; Kaplan, M. S.; McLain, B. T. et al.
System: The UNT Digital Library
Impact of design options on natural circulation performance of the AFR-300 advanced fast reactor. (open access)

Impact of design options on natural circulation performance of the AFR-300 advanced fast reactor.

The AFR-300, Advanced Fast Reactor (300 Mwe), has been proposed as a Generation IV concept. It could also be used to dispose of surplus weapons grade plutonium or as an actinide burner for transmutation of high level radioactive waste. AFR-300 uses metallic fuel and sodium coolant. The design of AFR-300 takes account of the successful design and operation of EBR-II, but the AFR-300 design includes a number of advances such as an advanced fuel cycle, inspectability and improved economics. One significant difference between AFR-300 and EBR-II is that AFR-300 is considerably larger. Another significant difference is that AFR-300 has no auxiliary EM pump in the primary loop to guarantee positive core flow when the main primary pumps are shut down. Thus, one question that has come up in connection with the AFR-300 design is whether natural circulation flow is sufficient to prevent damage to the core if the primary pumps fail. Insufficient natural circulation flow through the core could result in high cladding temperatures and cladding failure due to eutectic penetration of the cladding by the metal fuel. The rate of eutectic penetration of the cladding is strongly temperature dependent, so cladding failure depends on how hot the cladding gets …
Date: March 7, 2002
Creator: Dunn, F. D.
System: The UNT Digital Library
An Optimal Ion Exchange Design for Removal of Cesium from Hanford Waste (open access)

An Optimal Ion Exchange Design for Removal of Cesium from Hanford Waste

Non-elutable crystalline silicotitanate (CST) ion-exchanger materials have been studied for removing cesium from a variety of radioactive wastes at several U.S. DOE sites over the last decade. For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP) in Hanford, the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. However, due to concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin, IONSIV IE-911 (CST in its engineered form) material is being proposed as a backup ion-exchange material for the removal of cesium from Hanford radioactive waste. This paper discusses the methodology used to determine the optimal CST ion-exchange column size to process all 16 separate batches of feeds from the ten targeted Hanford waste tanks. The optimal design ensures the best utilization of CST material and therefore results in a minimum amount of spent CST.
Date: March 7, 2002
Creator: Hang, T.
System: The UNT Digital Library
Progress of the RERTR program in 2001. (open access)

Progress of the RERTR program in 2001.

This paper describes the 2001 progress achieved by the Reduced Enrichment for Research and Test Reactors (RERTR) Program in collaboration with its many international partners. Postirradiation examinations of microplates have continued to reveal excellent irradiation behavior of U-Mo dispersion fuels in a variety of compositions and irradiating conditions. Irradiation of two new batches of miniplates of greater sizes was completed in the ATR to investigate the swelling behavior of these fuels under prototypic conditions. These materials hold the promise of achieving the program goal of developing LEU research reactor fuels with uranium densities in the 8-9 g/cm{sup 3} range. Qualification of the U-Mo dispersion fuels has been delayed by a patent issue involving KAERI. Test fuel elements with uranium density of 6 g/cm{sup 3} are being fabricated by BWXT and are expected to begin undergoing irradiation in the HFR-Petten reactor around March 2003, with a goal of qualifying this fuel by mid-2005. U-Mo fuel with uranium density of 8-9 g/cm{sup 3} is expected to be qualified by mid-2007. Final irradiation tests of LEU {sup 99}Mo targets in the RAS-GAS reactor at BATAN, in Indonesia, had to be postponed because of the 9/11 attacks, but the results collected to date indicate …
Date: March 7, 2002
Creator: Travelli, A.
System: The UNT Digital Library
Antimicrobial Properties of Diamondlike Carbon-Silver-Platinum Nanocomposite Thin Films (open access)

Antimicrobial Properties of Diamondlike Carbon-Silver-Platinum Nanocomposite Thin Films

Silver and platinum were incorporated within diamondlike carbon (DLC) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films reveals that the metals self-assemble into particulate nanocomposite structures. Nanoindentation testing has shown that diamondlike carbon-silver films exhibit hardness and Young's modulus values of approximately 37 GPa and 333 GPa, respectively. DLC-silver-platinum films exhibited antimicrobial properties against Staphylococcus bacteria. Diamondlike carbon-biofunctional metal nanocomposite films have a variety of potential medical and antimicrobial applications.
Date: March 7, 2005
Creator: CHRISTOPHER, BERRY
System: The UNT Digital Library
Characterization of Microbial Communities in TCE-Contaminated Seep Zone Sediments (open access)

Characterization of Microbial Communities in TCE-Contaminated Seep Zone Sediments

Hundreds of sites across the United States contain trichloroethene (TCE) contamination, including the Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. Previous studies have indicated that microorganisms are capable of efficiently degrading TCE to nonhazardous end products. In this project, molecular and growth based methods were used for microbial characterization of a TCE impacted seepzone where TCE degradation is naturally occurring. The results from this work provide clear evidence that the SRB may play a significant role in TCE degradation along the Twin Lakes seepline.
Date: March 7, 2005
Creator: ROBIN, BRIGMON
System: The UNT Digital Library
Joint inversion for mapping subsurface hydrologicalparameters (open access)

Joint inversion for mapping subsurface hydrologicalparameters

Using electromagnetic (EM) and seismic travel time data and a least-square criteria, a two-dimensional joint inversion algorithm is under development to assess the feasibility of directly mapping subsurface hydrological properties in a crosswell setup. A simplified Archie's law combined with the time average equation relates the magnetic fields and seismic travel time to two hydrological parameters; rock porosity and pore fluid electrical conductivity. For simplicity, the hydrological parameter distributions are assumed to be two-dimensional. Preliminary results show that joint inversion does have better resolving power for the interpretation than using the EM method alone. Various inversion scenarios have been tested, and it has been found that alternately perturbing just one of the two parameters at each iteration gives the best data fit.
Date: March 7, 2001
Creator: Tseng, Hung-Wen & Lee, Ki Ha
System: The UNT Digital Library
Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand (open access)

Uranyl Sequestration: Synthesis and Structural Characterization of Uranyl Complexes with a Tetradentate Methylterephthalamide Ligand

Uranyl complexes of a bis(methylterephthalamide) ligand (LH{sub 4}) have been synthesized and characterized by X-ray crystallography. The structure is an unexpected [Me{sub 4}N]{sub 8}[L(UO{sub 2})]{sub 4} tetramer, formed via coordination of the two MeTAM units of L to two uranyl moieties. Addition of KOH to the tetramer gave the corresponding monomeric uranyl methoxide species [Me{sub 4}N]K{sub 2}[LUO{sub 2}(OMe)].
Date: March 7, 2011
Creator: Ni, Chengbao; Shuh, David & Raymond, Kenneth
System: The UNT Digital Library
Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor (open access)

Observation of Non-Maxwellian Electron Distributions in th e NSTX Divertor

The scrape-off layer plasma at the tokamak region is characterized by open field lines and often contains large variations in plasma properties along these field-lines. Proper characterization of local plasma conditions is critical to assessing plasma-material interaction processes occuring at the target. Langmuir probes are frequently employed in tokamak divertors but are challenging to interpretation. A kinetic interpretation for Langmuir probes in NSTX has yielded non-Maxwellian electron distributions in the divertor characterized by cool bulk populations and energetic tail populations with temperatures of 2-4 times the bulk. Spectroscopic analysis and modeling confirms the bulk plasma temperature and density which can only be obtained with the kinetic interpretation
Date: March 7, 2013
Creator: M.A. Jaworski, et. al.
System: The UNT Digital Library
Mulard: A Multigroup Thermal Radiation Diffusion Mini-Application (open access)

Mulard: A Multigroup Thermal Radiation Diffusion Mini-Application

None
Date: March 7, 2012
Creator: Brunner, T A
System: The UNT Digital Library
An Investigation of X-ray Luminosity versus Crystalline Powder Granularity (open access)

An Investigation of X-ray Luminosity versus Crystalline Powder Granularity

At the High-throughput Discovery of Scintillator Materials Facility at Lawrence Berkeley National Laboratory, scintillators are synthesized by solid-state reaction or melt mixing, forming crystalline powders. These powders are formed in various granularity and the crystal grain size affects the apparent luminosity of the scintillator. To accurately predict a &quot;full-size&quot; scintillator&#x27;s crystal luminosity, the crystal luminosity as a function of crystal granularity size has to be known. In this study, we examine Bi{sub 4}Ge{sub 3}O{sub 12} (BGO), Lu{sub 2}SiO{sub 5}:Ce (LSO), YAlO{sub 3}:Ce (YAP:Ce), and CsBa{sub 2}I{sub 5}:Eu{sup 2+} (CBI) luminosities as a function of crystalline grain size. The highest luminosities were measured for 600- to 1000-{micro}m crystal grain sizes for BGO and LSO, for 310- to 600-{micro}m crystal grain sizes for CBI, and for crystal grains larger than 165{micro}m for YAP:Ce. Crystal grains that were larger than 1 mm had a lower packing fraction, and smaller grains were affected by internal scattering. We measured a 34% decrease in luminosity for BGO when decreasing from the 600- to 1000- {micro}m crystal grain size range down to the 20- to 36-{micro}m range. The corresponding luminosity decrease for LSO was 44% for the same grain size decrease. YAP:Ce exhibited a luminosity decrease of …
Date: March 7, 2012
Creator: Borade, Ramesh & Bourret-Courchesne, Edith
System: The UNT Digital Library