CRYSTALLIZATION IN MULTICOMPONENT GLASSES (open access)

CRYSTALLIZATION IN MULTICOMPONENT GLASSES

In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.
Date: October 8, 2009
Creator: AA, KRUGER & PR, HRMA
Object Type: Article
System: The UNT Digital Library
Anode Sheath Switching in a Carbon Nanotube Arc Plasma (open access)

Anode Sheath Switching in a Carbon Nanotube Arc Plasma

The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.
Date: April 8, 2008
Creator: Abe Fetterman, Yevgeny Raitses, and Michael Keidar
Object Type: Report
System: The UNT Digital Library
Electricity: The Road Toward Restructuring (open access)

Electricity: The Road Toward Restructuring

The Public Utility Holding Company Act of 1935 (PUHCA) and the Federal Power Act (FPA) were enacted to eliminate unfair practices and other abuses by electricity and gas holding companies by requiring federal control and regulation of interstate public utility holding companies. Comprehensive energy legislation has passed the House and Senate. The House passed H.R. 6 on April 11, 2003. On July 31, 2003, the Senate suspended debate on S. 14, inserted the text of H.R. 4 (107th Congress) as a substitute, and passed H.R. 6. A conference agreement was reached November 17, 2003, and passed by the House the next day. H.R. 6 includes an electricity title that would, in part, repeal PUHCA, would prospectively repeal the mandatory purchase requirement under PURPA, and would create an electric reliability organization. On June 15, 2004, H.R. 4503, a comprehensive energy policy bill, passed the House.
Date: January 8, 2003
Creator: Abel, Amy & Parker, Larry
Object Type: Report
System: The UNT Digital Library
Electricity: The Road Toward Restructuring (open access)

Electricity: The Road Toward Restructuring

The Public Utility Holding Company Act of 1935 (PUHCA) and the Federal Power Act (FPA) were enacted to eliminate unfair practices and other abuses by electricity and gas holding companies by requiring federal control and regulation of interstate public utility holding companies. Comprehensive energy legislation has passed the House and Senate. The House passed H.R. 6 on April 11, 2003. On July 31, 2003, the Senate suspended debate on S. 14, inserted the text of H.R. 4 (107th Congress) as a substitute, and passed H.R. 6. A conference agreement was reached November 17, 2003, and passed by the House the next day. H.R. 6 includes an electricity title that would, in part, repeal PUHCA, would prospectively repeal the mandatory purchase requirement under PURPA, and would create an electric reliability organization. On June 15, 2004, H.R. 4503, a comprehensive energy policy bill, passed the House.
Date: April 8, 2003
Creator: Abel, Amy & Parker, Larry
Object Type: Report
System: The UNT Digital Library

Characterization and Development of Advanced Heat Transfer Technologies

Advancing heat transfer technologies is a critical factor in power electronics equipment. NREL aims to characterize and develop advanced heat transfer technologies.
Date: November 8, 2007
Creator: Abraham, T.
Object Type: Presentation
System: The UNT Digital Library
Reduction of Tropical Cloudiness by Soot (open access)

Reduction of Tropical Cloudiness by Soot

Measurements and models show that enhanced aerosol concentrations can augment cloud albedo not only by increasing total droplet cross-sectional area, but also by reducing precipitation and thereby increasing cloud water content and cloud coverage. Aerosol pollution is expected to exert a net cooling influence on the global climate through these conventional mechanisms. Here we demonstrate an opposite mechanism through which aerosols can reduce cloud cover and thus significantly offset aerosol-induced radiative cooling at the top of the atmosphere on a regional scale. In model simulations the daytime clearing of trade cumulus is hastened and intensified by solar heating in dark haze (as found over much of the northern Indian Ocean during the northeast monsoon).
Date: May 8, 2000
Creator: Ackerman, A. S.; Toon, O. B.; Stevens, D. E.; Heymsfield, A. J. & Ramanathan, V.
Object Type: Report
System: The UNT Digital Library
Education Vouchers: Constitutional Issues and Cases (open access)

Education Vouchers: Constitutional Issues and Cases

This report details the constitutional standards that currently apply to indirect aid programs and summarizes all of the pertinent state and federal court decisions, including the Ohio case that will be heard by the Supreme Court. On September 25, 2001, the Supreme Court agreed to review a case raising the controversial issue of the constitutionality of education vouchers. In Zelman v. Simmons-Harris the Sixth Circuit held Ohio’s Pilot Scholarship Program, which provided up to $2500 to help low-income students in Cleveland’s public schools attend private schools in the city, to violate the establishment of religion clause of the First Amendment.
Date: April 8, 2003
Creator: Ackerman, David M.
Object Type: Report
System: The UNT Digital Library
Qcd physics: study of jet shapes in inclusive jet production in ppbar collisions at sqrt s = 1.96 tev (open access)

Qcd physics: study of jet shapes in inclusive jet production in ppbar collisions at sqrt s = 1.96 tev

We present a search for excited and exotic electrons (e*) decaying to an electron and a photon, both with high transverse momentum. We use 202 pb{sup -1} of data collected in p{bar p} collisions at {radical}s = 1.96 TeV with the CDF II detector. No signal above standard model expectation is seen for associated ee* production. We discuss the e* sensitivity in the parameter space of the excited electron mass M{sub e*} and the compositeness energy scale {Lambda}. In the contact interaction model, we exclude 132 GeV/c{sup 2} < M{sub e*} < 879 GeV/c{sup 2} for {Lambda} = M{sub e*} at 95% confidence level (C.L.). In the gauge-mediated model, we exclude 126 GeV/c{sup 2} < M{sub e*} < 430 GeV/c{sup 2} at 95% C.L. for the phenomenological coupling f/{Lambda} {approx} 10{sup -2} GeV{sup -1}.
Date: May 8, 2005
Creator: Acosta, D.
Object Type: Report
System: The UNT Digital Library
Scaling Properties of Hyperon Production in Au + Au Collisions at sqrt sNN = 200 GeV (open access)

Scaling Properties of Hyperon Production in Au + Au Collisions at sqrt sNN = 200 GeV

We present the scaling properties of Lambda, Xi, and their anti-particles produced at mid-rapidity in Au+Au collisions at RHIC at psNN = 200 GeV. The yield of multi-strange baryons per participant nucleon increases from peripheral to central collisions more rapidly than the Lambda yield, which appears to correspond to an increasing strange quark density of matter produced. The value of the strange phase space occupancy factor gamma s, obtained from a thermal model fit to the data, approaches unity for the most central collisions. We also show that the nuclear modification factors, RCP, of Lambda and Xi are consistent with each other and with that of protons in the transverse momentum range2.0< pT< 5.0 GeV/c. This scaling behaviour is consistent with a scenario of hadron formation from constituent quark degrees of freedom through quark recombination or coalescence.
Date: June 8, 2006
Creator: Adams, J.
Object Type: Article
System: The UNT Digital Library
Azimuthally sensitive HBT in Au+Au collisions at sqrt(snn) = 200 GeV (open access)

Azimuthally sensitive HBT in Au+Au collisions at sqrt(snn) = 200 GeV

No abstract prepared.
Date: December 8, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type: Article
System: The UNT Digital Library
Photon and neutral pion production in Au+Au collisions at {radical}s{sub NN} = 130 GeV (open access)

Photon and neutral pion production in Au+Au collisions at {radical}s{sub NN} = 130 GeV

We report the first inclusive photon measurements about mid-rapidity (|y| < 0.5) from {sup 197}Au + {sup 197}Au collisions at {radical}s{sub NN} = 130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks measured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of {Delta}E/E {approx} 2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum (p{sub t}) spectra of {pi}{sup 0} mesons about mid-rapidity (|y| < 1) via the {pi}{sup 0} {yields} {gamma}{gamma} decay channel. The fractional contribution of the {pi}{sup 0} {yields} {gamma}{gamma} decay to the inclusive photon spectrum decreases by 20% {+-} 5% between p{sub t} = 1.65 GeV/c and p{sub t} = 2.4 GeV/c in the most central events, indicating that relative to {pi}{sup 0} {yields} {gamma}{gamma} decay the contribution of other photon sources is substantially increasing.
Date: January 8, 2004
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Object Type: Article
System: The UNT Digital Library
PROJECTIZING AN OPERATING NUCLEAR FACILITY (open access)

PROJECTIZING AN OPERATING NUCLEAR FACILITY

This paper will discuss the evolution of an operations-based organization to a project-based organization to facilitate successful deactivation of a major nuclear facility. It will describe the plan used for scope definition, staff reorganization, method estimation, baseline schedule development, project management training, and results of this transformation. It is a story of leadership and teamwork, pride and success. Workers at the Savannah River Site's (SRS) F Canyon Complex (FCC) started with a challenge--take all the hazardous byproducts from nearly 50 years of operations in a major, first-of-its-kind nuclear complex and safely get rid of them, leaving the facility cold, dark, dry and ready for whatever end state is ultimately determined by the United States Department of Energy (DOE). And do it in four years, with a constantly changing workforce and steadily declining funding. The goal was to reduce the overall operating staff by 93% and budget by 94%. The facilities, F Canyon and its adjoined sister, FB Line, are located at SRS, a 310-square-mile nuclear reservation near Aiken, S.C., owned by DOE and managed by Washington Group International subsidiary Washington Savannah River Company (WSRC). These facilities were supported by more than 50 surrounding buildings, whose purpose was to provide support …
Date: July 8, 2007
Creator: Adams, N
Object Type: Article
System: The UNT Digital Library
PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN (open access)

PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project-Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Seven of the cycles were completed in the 12 inch IX Column and sixteen cycles were completed in the 24 inch IX Column. Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 2 1/2 times better than the design requirements of the WTP full-scale system. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. In downflow of the Regeneration and Simulant Introduction steps, the resin bed particles pack tightly together and produce higher hydraulic pressures than that found in …
Date: November 8, 2006
Creator: Adamson, D
Object Type: Article
System: The UNT Digital Library
Bendable X-ray Optics at the ALS: Design, Tuning, Performance and Applications (open access)

Bendable X-ray Optics at the ALS: Design, Tuning, Performance and Applications

We review the development at the Advanced Light Source (ALS) of bendable x-ray optics widely used for focusing of beams of soft and hard x-rays. Typically, the focusing is divided in the tangential and sagittal directions into two elliptically cylindrical reflecting elements, the so-called Kirkpatrick-Baez (KB) pair [1]. Because fabrication of elliptical surfaces is complicated, the cost of directly fabricated tangential elliptical cylinders is often prohibitive. This is in contrast to flat optics, that are simpler to manufacture and easier to measure by conventional interferometry. The figure of a flat substrate can be changed by placing torques (couples) at each end. Equal couples form a tangential cylinder, and unequal couples can approximate a tangential ellipse or parabola. We review the nature of the bending, requirements and approaches to the mechanical design, and describe a technique developed at the ALS Optical Metrology Laboratory (OML) for optimal tuning of bendable mirrors before installation in the beamline [2]. The tuning technique adapts a method previously used to adjust bendable mirrors on synchrotron radiation beamlines [3]. However, in our case, optimal tuning of a bendable mirror is based on surface slope trace data obtained with a slope measuring instrument--in our case, the long trace …
Date: September 8, 2008
Creator: Advanced Light Source, Lawrence Berkeley National Laboratory; Yashchuk, Valeriy V.; Church, Matthew N.; Knight, Jason W.; Kunz, Martin; MacDowell, Alastair A. et al.
Object Type: Article
System: The UNT Digital Library
Simple Stringy Dynamical SUSY Breaking (open access)

Simple Stringy Dynamical SUSY Breaking

We present simple string models which dynamically break supersymmetry without non-Abelian gauge dynamics. The Fayet model, the Polonyi model, and the O'Raifeartaigh model each arise from D-branes at a specific type of singularity. D-brane instanton effects generate the requisite exponentially small scale of supersymmetry breaking.
Date: August 8, 2007
Creator: Aharony, Ofer; /Weizmann Inst. /Stanford U., Phys. Dept. /SLAC; Kachru, Shamit; Silverstein, Eva & /Stanford U., Phys. Dept. /SLAC
Object Type: Article
System: The UNT Digital Library
European Union–U.S. Trade and Investment Relations: Key Issues (open access)

European Union–U.S. Trade and Investment Relations: Key Issues

None
Date: April 8, 2008
Creator: Aheam, Raymond J.; Fischer, John W.; Goldfarb, Charles B.; Hanrahan, Charles E.; Eubanks, Walter W. & Rubin, Janice E.
Object Type: Report
System: The UNT Digital Library
Trade and the Americas (open access)

Trade and the Americas

None
Date: April 8, 2002
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Trade Legislation in the 106th Congress: An Overview (open access)

Trade Legislation in the 106th Congress: An Overview

None
Date: February 8, 2000
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges (open access)

U.S.-European Union Trade Relations: Issues and Policy Challenges

This report includes information regarding issues and policy challenges with U.S.-European trade relations. Growing strains, resolving longstanding disputes, and strengthening the multilateral trading system are among topics discussed in this report.
Date: June 8, 2004
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Multi-Model Combination Techniques for Hydrological Forecasting: Application to Distributed Model Intercomparison Project Results (open access)

Multi-Model Combination Techniques for Hydrological Forecasting: Application to Distributed Model Intercomparison Project Results

This paper examines several multi-model combination techniques: the Simple Multimodel Average (SMA), the Multi-Model Super Ensemble (MMSE), Modified Multi-Model Super Ensemble (M3SE) and the Weighted Average Method (WAM). These model combination techniques were evaluated using the results from the Distributed Model Intercomparison Project (DMIP), an international project sponsored by the National Weather Service (NWS) Office of Hydrologic Development (OHD). All of the multi-model combination results were obtained using uncalibrated DMIP model outputs and were compared against the best uncalibrated as well as the best calibrated individual model results. The purpose of this study is to understand how different combination techniques affect the skill levels of the multi-model predictions. This study revealed that the multi-model predictions obtained from uncalibrated single model predictions are generally better than any single member model predictions, even the best calibrated single model predictions. Furthermore, more sophisticated multi-model combination techniques that incorporated bias correction steps work better than simple multi-model average predictions or multi-model predictions without bias correction.
Date: May 8, 2006
Creator: Ajami, N.; Duan, Q.; Gao, X. & Sorooshian, S.
Object Type: Article
System: The UNT Digital Library
{sup 17}O NMR Investigation of Oxidative Degradation in Polymers Under Gamma-Irradiation (open access)

{sup 17}O NMR Investigation of Oxidative Degradation in Polymers Under Gamma-Irradiation

The {gamma}-irradiated-oxidation of pentacontane (C{sub 50}H{sub 102}) and the polymer polyisoprene was investigated as a function of oxidation level using {sup 17}O nuclear magnetic resonance (NMR) spectroscopy. It is demonstrated that by using {sup 17}O labeled O{sub 2} gas during the {gamma}-irradiation process, details about the oxidative degradation mechanisms can be directly obtained from the analysis of the {sup 17}O NMR spectra. Production of carboxylic acids is the primary oxygen-containing functionality during the oxidation of pentacontane, while ethers and alcohols are the dominant oxidation product observed for polyisoprene. The formation of ester species during the oxidation process is very minor for both materials, with water also being produced in significant amounts during the radiolytic oxidation of polyisoprene. The ability to focus on the oxidative component of the degradation process using {sup 17}O NMR spectroscopy demonstrates the selectivity of this technique over more conventional approaches.
Date: March 8, 2000
Creator: Alam, Todd M.; Celina, Mathias C.; Assink, Roger A.; Clough, Roger Lee & Gillen, Kenneth T.
Object Type: Article
System: The UNT Digital Library
Probing Dark Energy via Weak Gravitational Lensing with the Supernova Acceleration Probe (SNAP) (open access)

Probing Dark Energy via Weak Gravitational Lensing with the Supernova Acceleration Probe (SNAP)

SNAP is a candidate for the Joint Dark Energy Mission (JDEM) that seeks to place constraints on the dark energy using two distinct methods. The first, Type Ia SN, is discussed in a separate white paper. The second method is weak gravitational lensing, which relies on the coherent distortions in the shapes of background galaxies by foreground mass structures. The excellent spatial resolution and photometric accuracy afforded by a 2-meter space-based observatory are crucial for achieving the high surface density of resolved galaxies, the tight control of systematic errors in the telescope's Point Spread Function (PSF), and the exquisite redshift accuracy and depth required by this project. These are achieved by the elimination of atmospheric distortion and much of the thermal and gravity loads on the telescope. The SN and WL methods for probing dark energy are highly complementary and the error contours from the two methods are largely orthogonal. The nominal SNAP weak lensing survey covers 1000 square degrees per year of operation in six optical and three near infrared filters (NIR) spanning the range 350 nm to 1.7 {micro}m. This survey will reach a depth of 26.6 AB magnitude in each of the nine filters and allow for …
Date: August 8, 2005
Creator: Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J. et al.
Object Type: Report
System: The UNT Digital Library
Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae (open access)

Supernova Acceleration Probe: Studying Dark Energy with Type Ia Supernovae

The Supernova Acceleration Probe (SNAP) will use Type Ia supernovae (SNe Ia) as distance indicators to measure the effect of dark energy on the expansion history of the Universe. (SNAP's weak-lensing program is described in a separate White Paper.) The experiment exploits supernova distance measurements up to their fundamental systematic limit; strict requirements on the monitoring of each supernova's properties leads to the need for a space-based mission. Results from pre-SNAP experiments, which characterize fundamental SN Ia properties, will be used to optimize the SNAP observing strategy to yield data, which minimize both systematic and statistical uncertainties. With early R&D funding, we have achieved technological readiness and the collaboration is poised to begin construction. Pre-JDEM AO R&D support will further reduce technical and cost risk. Specific details on the SNAP mission can be found in Aldering et al. (2004, 2005). The primary goal of the SNAP supernova program is to provide a dataset which gives tight constraints on parameters which characterize the dark-energy, e.g. w{sub 0} and w{sub a} where w(a) = w{sub 0} + w{sub a}(1-a). SNAP data can also be used to directly test and discriminate among specific dark energy models. We will do so by building the …
Date: August 8, 2005
Creator: Albert, J.; Aldering, G.; Allam, S.; Althouse, W.; Amanullah, R.; Annis, J. et al.
Object Type: Report
System: The UNT Digital Library
SuperB: a Linear High-Luminosity B Factory (open access)

SuperB: a Linear High-Luminosity B Factory

This paper is based on the outcome of the activity that has taken place during the recent workshop on ''SuperB in Italy'' held in Frascati on November 11-12, 2005. The workshop was opened by a theoretical introduction of Marco Ciuchini and was structured in two working groups. One focused on the machine and the other on the detector and experimental issues.. The present status on CP is mainly based on the results achieved by BABAR and Belle. Establishment of the indirect CP violation in B sector in 2001 and of the direct CP violation in 2004 thanks to the success of PEP-II and KEKB e{sup +}e{sup -} asymmetric B Factories operating at the center of mass energy corresponding to the mass of the {Upsilon}(4S ). With the two B Factories taking data, the Unitarity Triangle is now beginning to be over constrained by improving the measurements of the sides and now also of the angles {alpha}, and {gamma}. We are also in presence of the very intriguing results about the measurements of sin2{beta} in the time dependent analysis of decay channels via penguin loops, where b {yields} s{bar s}s and b {yields} s{bar d}d. {tau} physics, in particular LFV search, …
Date: February 8, 2006
Creator: Albert, J.; Bettarini, S.; Biagini, M.; Bonneaud, G.; Cai, Y.; Calderini, G. et al.
Object Type: Report
System: The UNT Digital Library