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Correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane (open access)

Correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane

Article on the correlation and prediction of partition coefficients between the gas phase and water, and the solvents dodecane and undecane.
Date: October 29, 2004
Creator: Abraham, M. H. (Michael H.) & Acree, William E. (William Eugene)
System: The UNT Digital Library
Azimuthal anisotropy in Au+Au collisions at {radical}s{sub NN} = 200 GeV (open access)

Azimuthal anisotropy in Au+Au collisions at {radical}s{sub NN} = 200 GeV

The results from the STAR Collaboration on directed flow (v{sub 1}), elliptic flow (v{sub 2}), and the fourth harmonic (v{sub 4}) in the anisotropic azimuthal distribution of particles from Au+Au collisions at {radical}s{sub NN} = 200 GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a Blast Wave model. For v{sub 2}, scaling with the number of constituent quarks and parton coalescence is discussed. For v{sub 4}, scaling with v{sub 22} and quark coalescence predictions for higher harmonic flow is discussed. The different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data. For v{sub 2}, scaling with the number of constituent quarks and parton coalescence are discussed. For v{sub 2}{sup 2} and quark coalescence are discussed.
Date: September 29, 2004
Creator: Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Akhipkin, D. et al.
System: The UNT Digital Library
Direct Experimental Evidence of Back-Surface Acceleration from Laser-Irradiated Foils (open access)

Direct Experimental Evidence of Back-Surface Acceleration from Laser-Irradiated Foils

Au foils were irradiated with a 100-TW, 100-fs laser at intensities greater than 10{sup 20} W/cm{sup 2} producing proton beams with a total yield of {approx} 10{sup 11} and maximum proton energy of > 9 MeV. Removing contamination from the back surface of Au foils with an Ar-ion sputter gun reduced the total yield of accelerated protons to less than 1% of the yield observed without removing contamination. Removing contamination the front surface (laser-interaction side) of the target had no observable effect on the proton beam. We present a one-dimensional particle-in-cell simulation that models the experiment. Both experimental and simulation results are consistent with the back-surface acceleration mechanism described in the text.
Date: March 29, 2004
Creator: Allen, Matthew; Patel, Pravesh K.; Mackinnon, Andrew; Price, Dwight; Wilks, Scott & Morse, Edward
System: The UNT Digital Library
Automatic Identification of the Templates in Matched Filtering (open access)

Automatic Identification of the Templates in Matched Filtering

In laser beam position determination, various shapes of markers may be used to identify different beams. When matched filtering is used for identifying the markers, one is faced with the challenge of determining the appropriate filter to use in the presence of distortions and marker size variability. If the incorrect filter is used, it will result in significant position uncertainty. Thus in the very first step of position detection one has to come up with an automated process to select the right template to use. The automated template identification method proposed here is based on a two-step approach. In the first step an approximate type of the object is determined. Then the filter is chosen based on the best size of the specific type. After the appropriate filter is chosen, the correlation peak position is used to identify the beam position. Real world examples of the application of this technique from the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory are presented.
Date: September 29, 2004
Creator: Awwal, A. S.
System: The UNT Digital Library
Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates (open access)

Accurate Position Sensing of Defocused Beams Using Simulated Beam Templates

In position detection using matched filtering one is faced with the challenge of determining the best position in the presence of distortions such as defocus and diffraction noise. This work evaluates the performance of simulated defocused images as the template against the real defocused beam. It was found that an amplitude modulated phase-only filter is better equipped to deal with real defocused images that suffer from diffraction noise effects resulting in a textured spot intensity pattern. It is shown that the there is a tradeoff of performance dependent upon the type and size of the defocused image. A novel automated system was developed that can automatically select the right template type and size. Results of this automation for real defocused images are presented.
Date: September 29, 2004
Creator: Awwal, A.; Candy, J.; Haynam, C.; Widmayer, C.; Bliss, E. & Burkhart, S.
System: The UNT Digital Library
High Level Waste Tank Closure Modeling with Geographic Information Systems (GIS) (open access)

High Level Waste Tank Closure Modeling with Geographic Information Systems (GIS)

Waste removal from 49 underground storage tanks located in two tank farms involves three steps: bulk waste removal, water washing to remove residual waste, and in some cases chemical cleaning to remove additional residual waste. Not all waste can be completely removed by these processes-resulting in some residual waste loading following cleaning. Completely removing this residual waste would be prohibitively expensive; therefore, it will be stabilized by filling the tanks with grout. Acceptable residual waste loading inventories were determined using one-dimensional groundwater transport modeling to predict future human exposure based on several scenarios. These modeling results have been incorporated into a geographic information systems (GIS) application for rapid evaluation of various tank closure options.
Date: July 29, 2004
Creator: BOLLINGER, JAMES
System: The UNT Digital Library
IFC HVAC Interface to EnergyPlus - A Case of Expanded Interoperability for Energy Simulation (open access)

IFC HVAC Interface to EnergyPlus - A Case of Expanded Interoperability for Energy Simulation

Tedious manual input of data that define a building, its systems and its expected pattern of use and operating schedules for building energy performance simulation has in the past diverted time and resources from productive simulation runs. In addition to its previously released IFCtoIDF utility that semiautomates the import of building geometry, the new IFC HVAC interface to EnergyPlus (released at the end of 2003) makes it possible to import and export most of the data that define HVAC equipment and systems in a building directly from and to other IFC compatible software tools. This reduces the manual input of other data needed for successful simulation with EnergyPlus to a minimum. The main purpose of this new interface is to enable import of HVAC equipment and systems definitions, generated by other IFC compatible software tools (such as HVAC systems design tools) and data bases, into EnergyPlus, and to write such definitions contained in EnergyPlus input files to the original IFC files from which building geometry was extracted for the particular EnergyPlus input. In addition, this interface sets an example for developers of other software tools how to import and/or export data other than building geometry from and/or into EnergyPlus. This …
Date: March 29, 2004
Creator: Bazjanac, Vladimir & Maile, Tobias
System: The UNT Digital Library
Computational Needs for Muon Accelerators. (open access)

Computational Needs for Muon Accelerators.

Muon accelerators contain beam lines and components which are unlike any found in existing accelerators. Production of the muons requires targets for beams with powers which are at or beyond what has currently been achieved. Many subsystems use solenoid focusing systems where at any given point, several magnets have a significant influence. The beams that are transported can have energy spreads of {+-}30% or more. The required emittances necessitate accurate tracking of particles with angles of tenths of a radian and which are positioned almost at the edge of the beam pipe. Tracking must be done not only in vacuum, but also in materials; therefore, statistical fluctuations must also be included. Design and simulation of muon accelerators requires software which can: accurately simulate the dynamics of solid and liquid targets under proton bombardment; predict the production of particles from these targets; accurately compute magnetic fields based on either a real magnet design or a model which includes end fields; and accurately design and simulate a beam line where the transported beam satisfies the above specifications and the beam line contains non-standard, overlapping elements. The requirements for computational tools will be discussed, the capabilities of existing tools will be described and …
Date: June 29, 2004
Creator: Berg, J. S.
System: The UNT Digital Library
Lattice disorder and magnetism in f-electron intermetallics (open access)

Lattice disorder and magnetism in f-electron intermetallics

Real materials can have real differences compared to ideal systems. For instance, non-Fermi liquid (NFL) behavior was initially thought to be due to chemical disorder, since the first such materials were all substituted. Although several nominally well-ordered NFL's have been discovered and extensively studied, the effect of disorder on the magnetic properties of f-electron intermetallic systems remains poorly understood. Disorder in NFL systems is reviewed from an experimental, local structure point of view, including a discussion of results on the nominally ordered U{sub 3}Ni{sub 3}Sn{sub 4} and CeCoIn{sub 5} systems, and the chemically disordered UCu{sub 4}Pd and CeRhRuSi{sub 2} systems.
Date: July 29, 2004
Creator: Booth, C.H.; Han, S.-W.; Skanthakumar, S. & Sarrao, J.L.
System: The UNT Digital Library
Shock Compressing Diamond to a Conducting Fluid (open access)

Shock Compressing Diamond to a Conducting Fluid

Laser generated shock reflectance data show that diamond undergoes a continuous transition from optically absorbing to reflecting between Hugoniot pressures 600<P{sub H}<1000 GPa. The data are consistent with diamond having a thermal population of carriers at P{sub H}{approx}600 GPa, undergoing band overlap metallization at P{sub H}{approx}1000 GPa and melting at 800<P{sub H}<1000 GPa. The results agree well with an equation of state model that predicts that elemental carbon remains solid throughout the interior of Neptune.
Date: July 29, 2004
Creator: Bradley, D K; Eggert, J H; Hicks, D G; Celliers, P M; Moon, S J; Cauble, R C et al.
System: The UNT Digital Library
ParaDiS on BlueGene/L: scalable line dynamics (open access)

ParaDiS on BlueGene/L: scalable line dynamics

We describe an innovative highly parallel application program, ParaDiS, which computes the plastic strength of materials by tracing the evolution of dislocation lines over time. We discuss the issues of scaling the code to tens of thousands of processors, and present early scaling results of the code run on a prototype of the BlueGene/L supercomputer being developed by IBM in partnership with the US DOE's ASC program.
Date: April 29, 2004
Creator: Bulatov, V.; Cai, W.; Fier, J.; Hiratani, M.; Pierce, T.; Tang, M. et al.
System: The UNT Digital Library
Flavor violation in warped extra dimensions and CP Asymmetries in B decays (open access)

Flavor violation in warped extra dimensions and CP Asymmetries in B decays

We show that CP asymmetries in b {yields} s hadronic decays are potentially affected by the presence of massive color-octet particles strongly coupled to the third generation quarks. Theories with warped extra dimensions provide natural candidates in the Kaluza-Klein excitations of gluons in scenarios where flavor-breaking by bulk fermion masses results in the localization of fermion wave-functions. Topcolor models, in which a new gauge interaction leads to top-condensation and a large top mass, also result in the presence of these color-octet states with TeV masses. We find that large effects are possible in modes such as B {yields} {phi}K{sub s}, B {yields} {eta}{prime}K{sub s} and B {yields} {pi}{sup 0}K{sub s} among others.
Date: April 29, 2004
Creator: Burdman, Gustavo
System: The UNT Digital Library
CIRCE, the Coherent Infrared Center at the ALS (open access)

CIRCE, the Coherent Infrared Center at the ALS

CIRCE (Coherent InfraRed CEnter) is a proposal for a new electron storage ring to be built at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). The ring design is optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. Among others, CIRCE operation includes three interesting CSR modes: ultra stable, femtosecond laser slicing and broadband bursting. CSR allows CIRCE to generate an extremely high flux in the terahertz frequency region. The many orders of magnitude increase in the intensity over that presently achievable by conventional sources, has the potential to enable new science experiments. The characteristics of CIRCE and of the different modes of operation are described in this paper.
Date: June 29, 2004
Creator: Byrd, John M.; De Santis, Stefano; Jung, Jin-Young; Li, Derun; Martin, Michael C.; McKinney, W. et al.
System: The UNT Digital Library
High Gradient Induction Cell (open access)

High Gradient Induction Cell

A concept being developed for high current electron beams may have application to HEDP and is described here. It involves the use of planar Blumlein stacks placed inside an induction cell. The output end of the Blumlein stack is applied across a high gradient insulator (HGI). These insulators have been used successfully in the presence of kilo Ampere-level electron beam currents for tens of nanoseconds at gradients of 20 MV/meter.
Date: November 29, 2004
Creator: Caporaso, G J
System: The UNT Digital Library
Chemical Origins of Permanent Set in a Peroxide Cured Filled Silicone Elastomer - Tensile and 1H NMR Analysis (open access)

Chemical Origins of Permanent Set in a Peroxide Cured Filled Silicone Elastomer - Tensile and 1H NMR Analysis

The aging of a commercial filled siloxane polymeric composite in states of high stress and Co-60 {gamma}-radiation exposure has been studied. DC-745 is a commercially available silicone elastomer consisting of dimethyl, methyl-phenyl, and vinyl-methyl siloxane monomers crosslinked with a peroxide vinyl specific curing agent. It is filled with {approx}30 wt.% mixture of high and low surface area silicas. This filled material is shown to be subject to permanent set if exposed to radiation while under tensile stress. Tensile modulus measurements show that the material gets marginally softer with combined radiation exposure and tensile strain as compared to material exposed to radiation without tensile strain. In addition, the segmental dynamics as measured by both uniaxial NMR relaxometry and Multiple Quantum NMR methods indicate that the material is undergoes radiatively-induced crosslinking in the absence of tensile strain and a combination of crosslinking and strain dependent increase in dynamic order parameter for the network chains. The MQ-NMR also suggests a small change in the number of polymer chains associated with the silica filler surface. Comparison of the prediction of the relative change in crosslink density from the NMR data as well as solvent swelling data and from that predicted from the Tobolsky model …
Date: October 29, 2004
Creator: Chinn, S.; Deteresa, S.; Shields, A.; Sawvel, A.; Balazs, B. & Maxwell, R. S.
System: The UNT Digital Library
An Internal LLNL Report: Spectroscopic Signature of Aging in (Delta)-Pu(Ga) (open access)

An Internal LLNL Report: Spectroscopic Signature of Aging in (Delta)-Pu(Ga)

Resonant Photoemission, a variant of Photoelectron Spectroscopy, has been demonstrated to have sensitivity to aging of Pu samples. The spectroscopic results are correlated with resistivity measurements and are shown to be the fingerprint of mesoscopic or nanoscale internal damage in the Pu physical structure. This means that a spectroscopic signature of internal damage due to aging in Pu has been established.
Date: December 29, 2004
Creator: Chung, B W; Fluss, M J; Haslam, J J; Schwartz, A J & Tobin, J G
System: The UNT Digital Library
LUX - a recirculating linac-based facility for ultrafast X-ray science (open access)

LUX - a recirculating linac-based facility for ultrafast X-ray science

We present recent developments in design concepts for LUX - a source of ultra-short synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science [1]. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1-10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, independently tunable harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and resistive wall wakefields. Timing jitter between pump lasers and x-ray pulses is minimized by …
Date: June 29, 2004
Creator: Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Heimann, P. et al.
System: The UNT Digital Library
Characterization of Uranium Solids Precipitated with Aluminosilicates (open access)

Characterization of Uranium Solids Precipitated with Aluminosilicates

At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation.
Date: April 29, 2004
Creator: Duff, M. C.
System: The UNT Digital Library
Studies of laser-driven radiative blast waves (open access)

Studies of laser-driven radiative blast waves

We have performed two sets of experiments looking at laser-driven radiating blast waves. In one set of experiments the effect of a drive laser's passage through a background gas on the hydrodynamical evolution of blast waves was examined. It was found that the laser's passage heats a channel in the gas, creating a region where a portion of the blast wave front had an increased velocity, leading to the formation of a bump-like protrusion on the blast wave. The second set of experiments involved the use of regularly spaced wire arrays to induce perturbations on a blast wave surface. The decay of these perturbations as a function of time was measured for various wave number perturbations and found to be in good agreement with theoretical predictions.
Date: April 29, 2004
Creator: Edwards, M J; Hansen, J; Edens, A; Ditmire, T; Adams, R; Rambo, P et al.
System: The UNT Digital Library
Radon Reduction Experience at a Former Uranium Processing Facility (open access)

Radon Reduction Experience at a Former Uranium Processing Facility

Approximately 6,200 cubic meters of waste containing about 2.0E8 MBq of radium-226 are stored in two large silos at the Fernald Site in southwest Ohio. The material is scheduled for retrieval, packaging, off site shipment and disposal by burial. Air in the silos above the stored material contained radon-222 at a concentration of 7.4 E5 Bq/L. Short-lived daughters formed by decay in these headspaces generated dose rates at contact with the top of the silos up to 1.05 mSv/hr and there complicate the process of retrieval. A Radon Control System (RCS) employing carbon adsorption beds has been designed under contract with the Fluor Fernald to remove most of the radon in the headspaces and maintain lower concentrations during periods when work on or above the domes is needed. Removing the radon also removes the short-lived daughters and reduces the dose rate near the domes to 20 to 30 {mu}Sv/hr. Failing to remove the radon would be costly, in the exposure of personnel needed to work extended periods at these moderate dose rates, or in dollars for the application of remote retrieval techniques. In addition, the RCS minimizes the potential for environmental releases. This paper describes the RCS, its mode of …
Date: February 29, 2004
Creator: Eger, K. J.; Rutherford, L.; Rickett, K.; Fellman, R. & Hungate, S.
System: The UNT Digital Library
A Generalized Mass Lumping Technique for Vector Finite Element Solutions of the Time Dependent Maxwell Equations (open access)

A Generalized Mass Lumping Technique for Vector Finite Element Solutions of the Time Dependent Maxwell Equations

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Date: July 29, 2004
Creator: Fisher, A; Rieben, R; Rodrigue, G & White, D
System: The UNT Digital Library
Design of a Multi-Channel Ultra-High Resolution Superconducting Gamma-Ray Spectrometer (open access)

Design of a Multi-Channel Ultra-High Resolution Superconducting Gamma-Ray Spectrometer

Superconducting Gamma-ray microcalorimeters operated at temperatures around {approx}0.1 K offer an order of magnitude improvement in energy resolution over conventional high-purity Germanium spectrometers. The calorimeters consist of a {approx}1 mm{sup 3} superconducting or insulating absorber and a sensitive thermistor, which are weakly coupled to a cold bath. Gamma-ray capture increases the absorber temperature in proportion to the Gamma-ray energy, this is measured by the thermistor, and both subsequently cool back down to the base temperature through the weak link. We are developing ultra-high-resolution Gamma-ray spectrometers based on Sn absorbers and superconducting Mo/Cu multilayer thermistors for nuclear non-proliferation applications. They have achieved an energy resolution between 60 and 90 eV for Gamma-rays up to 100 keV. We also build two-stage adiabatic demagnetization refrigerators for user-friendly detector operation at 0.1 K. We present recent results on the performance of single pixel Gamma-ray spectrometers, and discuss the design of a large detector array for increased sensitivity.
Date: November 29, 2004
Creator: Friedrich, S.; Terracol, S. F.; Miyazaki, T.; Drury, O. B.; Ali, Z. A.; Cunningham, M. F. et al.
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
System: The UNT Digital Library
High Resolution Transmission Grating Spectrometer for Edge Toroidal Rotation Measurements of Tokamak Plasmas (open access)

High Resolution Transmission Grating Spectrometer for Edge Toroidal Rotation Measurements of Tokamak Plasmas

We present a high throughput (f/3) visible (3500 - 7000 Angstrom) Doppler spectrometer for toroidal rotation velocity measurements of the Alcator C-Mod tokamak plasma. The spectrometer has a temporal response of 1 ms and a rotation velocity sensitivity of {approx}10{sup 5} cm/s. This diagnostic will have a tangential view and map out the plasma rotation at several locations along the outer half of the minor radius (r/a > 0.5). The plasma rotation will be determined from the Doppler shifted wavelengths of D{sub alpha} and magnetic and electric dipole transitions of highly ionized impurities in the plasma. The fast time resolution and high spectral resolving power are possible due to a 6' diameter circular transmission grating that is capable of {lambda}/{Delta}{lambda} {approx} 15500 at 5769 Angstrom in conjunction with a 50 {micro}m slit.
Date: April 29, 2004
Creator: Graf, A.; May, M.; Beiersdorfer, P.; Magee, E.; Lawrence, M.; Terry, J. et al.
System: The UNT Digital Library