Access Grid node minimum requirements. (open access)

Access Grid node minimum requirements.

The Access Grid is a group-to-group collaborative system developed at Argonne National Laboratory. The system is designed to support high-fidelity, high-bandwidth interactions. This document specifies the minimum requirements that need to be fulfilled for a space to be considered an Access Grid Node.
Date: June 27, 2002
Creator: Judson, I. R.
Object Type: Report
System: The UNT Digital Library
Analysis of Gd5(Si2Ge2) Microstructure and Phase Transition (open access)

Analysis of Gd5(Si2Ge2) Microstructure and Phase Transition

With the recent discovery of the giant magnetocaloric effect and the beginning of extensive research on the properties of Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, a necessity has developed for a better understanding of the microstructure and crystal structure of this family of rare earth compounds with startling phenomenological properties. The aim of this research is to characterize the microstructure of the Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}, with X {approx_equal} 2 and its phase change by using both transmission and electron microscopes. A brief history of past work on Gd{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4} is necessary to understand this research in its proper context.
Date: June 27, 2002
Creator: Meyers, John Scott
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Arctic National Wildlife Refuge: Legislative Issues (open access)

Arctic National Wildlife Refuge: Legislative Issues

This report discusses the ongoing debate about whether or not to open the Arctic National Wildlife Refuge (ANWR) for energy development. The report discusses arguments for and against such development and focuses especially on related pieces of legislation that directly affects the future of the ANWR.
Date: June 27, 2002
Creator: Corn, M. Lynne; Gelb, Bernard A. & Baldwin, Pamela
Object Type: Report
System: The UNT Digital Library
Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography (open access)

Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.
Date: June 27, 2002
Creator: Roberts, Kenneth Paul
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Broadband Internet Access and the Digital Divide: Federal Assistance Programs (open access)

Broadband Internet Access and the Digital Divide: Federal Assistance Programs

Some policymakers, believing that disparities in broadband access across American society could have adverse economic and social consequences on those left behind, assert that the federal government should play a more active role to avoid a “digital divide” in broadband access. One approach is for the federal government to provide financial assistance to support broadband deployment in underserved areas. Others, however, believe that federal assistance for broadband deployment is not appropriate. Some opponents question the reality of the “digital divide,” and argue that federal intervention in the broadband marketplace would be premature and, in some cases, counterproductive.
Date: June 27, 2002
Creator: Kruger, Lennard G.
Object Type: Report
System: The UNT Digital Library
Calculations of Neutral Beam Ion Confinement for the National Spherical Torus Experiment (open access)

Calculations of Neutral Beam Ion Confinement for the National Spherical Torus Experiment

The spherical torus (ST) concept underlies several contemporary plasma physics experiments, in which relatively low magnetic fields, high plasma edge q, and low aspect ratio combine for potentially compact, high beta and high performance fusion reactors. An important issue for the ST is the calculation of energetic ion confinement, as large Larmor radius makes conventional guiding center codes of limited usefulness and efficient plasma heating by RF and neutral beam ion technology requires minimal fast ion losses. The National Spherical Torus Experiment (NSTX) is a medium-sized, low aspect ratio ST, with R=0.85 m, a=0.67 m, R/a=1.26, Ip*1.4 MA, Bt*0.6 T, 5 MW of neutral beam heating and 6 MW of RF heating. 80 keV neutral beam ions at tangency radii of 0.5, 0.6 and 0.7 m are routinely used to achieve plasma betas above 30%. Transport analyses for experiments on NSTX often exhibit a puzzling ion power balance. It will be necessary to have reliable beam ion calculations to distinguish among the source and loss channels, and to explore the possibilities for new physics phenomena, such as the recently proposed compressional Alfven eigenmode ion heating.
Date: June 27, 2002
Creator: Redi, M. H.; Darrow, D. S.; Egedal, J.; Kaye, S. M. & White, R. B.
Object Type: Report
System: The UNT Digital Library
Characterization and recovery of solvent entrained during the use of centrifugal contactors. (open access)

Characterization and recovery of solvent entrained during the use of centrifugal contactors.

In this work, we determined how a decanter for the aqueous effluents would work for solvent extraction operations using a centrifugal contactor. Solvent entrainment was measured in the raffinate and strip aqueous effluents in the caustic-side solvent extraction (CSSX) process. Values were obtained for both the solvent concentration and its droplet size distribution. The mixing intensity of the two phases in the mixing zone of the contactor was used to simulate the performance of lab-scale, pilot-plant, and plant-scale contactors. The droplet size distributions were used to estimate the amount of solvent that would be recovered using a decanter tank. It was concluded that the performance of decanter tanks will not be as effective in solvent recovery in the CSSX plan as that of other equipment, such as centrifuges and coalescers. Future testing is recommended to verify the performance of this alternative equipment.
Date: June 27, 2002
Creator: Arafat, H. A.; Hash, M. C.; Hebden, A. S. & Leonard, R. A.
Object Type: Report
System: The UNT Digital Library
Effect of Interstitial Impurities on the Magnetic Transitions of Er-rich PrxEr1-x Alloys (open access)

Effect of Interstitial Impurities on the Magnetic Transitions of Er-rich PrxEr1-x Alloys

None
Date: June 27, 2002
Creator: Gschneidner, K. A.; Pecharsky, A. O.; Wu, Y. L. & Pecharsky, V. K.
Object Type: Article
System: The UNT Digital Library
Electrocatalytic Materials and Techniques for the Anodic Oxidation of Various Organic Compounds (open access)

Electrocatalytic Materials and Techniques for the Anodic Oxidation of Various Organic Compounds

The focus of this thesis was first to characterize and improve the applicability of Fe(III) and Bi(V) doped PbO{sub 2} film electrodes for use in anodic O-transfer reactions of toxic and waste organic compounds, e.g. phenol, aniline, benzene, and naphthalene. Further, they investigated the use of alternative solution/electrode interfacial excitation techniques to enhance the performance of these electrodes for remediation and electrosynthetic applications. Finally, they have attempted to identify a less toxic metal oxide film that may hold promise for future studies in the electrocatalysis and photoelectrocatalysis of O-transfer reactions using metal oxide film electrodes.
Date: June 27, 2002
Creator: Treimer, Stephen Everett
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Electronic Payments and the U.S. Payments System (open access)

Electronic Payments and the U.S. Payments System

This report provides a framework for understanding the paper-based and electronic components of the current U.S. payments system. It begins with a basic overview of the payments system, explaining the relative size and growth of various methods of payment. The report discusses paper-based payments and then examines the operations of wholesale and retail electronic payments. Finally, the report discusses some of the major policy issues concerning the regulation and supervision of electronic payments.
Date: June 27, 2002
Creator: Eubanks, Walter W. & Smale, Pauline
Object Type: Report
System: The UNT Digital Library
Energy Tax Policy (open access)

Energy Tax Policy

Omnibus energy legislation (H.R. 4) that is now in conference would expand energy tax incentives significantly. The House passed the bill on August 2, 2001, and the Senate approved its version April 25, 2002. Several energy tax issues are addressed in these bills: 1) tax incentives to increase the supply of oil and gas, and the demand for coal; 2) energy tax issues relating to energy conservation and energy efficiency; 3) energy tax issues relating to alternative fuels; 4) selected issues relating to electricity restructuring; and 5) expiring energy tax provisions.
Date: June 27, 2002
Creator: Lazzari, Salvatore
Object Type: Report
System: The UNT Digital Library
Enhancing the Properties of Carbon and Gold Substrates by Surface Modification (open access)

Enhancing the Properties of Carbon and Gold Substrates by Surface Modification

The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol …
Date: June 27, 2002
Creator: Harnisch, Jennifer Anne
Object Type: Thesis or Dissertation
System: The UNT Digital Library
ERISA's Impact on Medical Malpractice and Negligence Claims Against Managed Care Plans (open access)

ERISA's Impact on Medical Malpractice and Negligence Claims Against Managed Care Plans

None
Date: June 27, 2002
Creator: Welborn, Angie A.
Object Type: Report
System: The UNT Digital Library
ERISA's Impact on Medical Malpractice and Negligence Claims Against Managed Care Plans (open access)

ERISA's Impact on Medical Malpractice and Negligence Claims Against Managed Care Plans

This report will examine the preemption provisions of ERISA, the U.S. Supreme Court’s interpretation of these provisions, selected cases applying ERISA to state medical malpractice and negligence claims, and the congressional response to the issue.
Date: June 27, 2002
Creator: Welborn, Angie A.
Object Type: Report
System: The UNT Digital Library
France: Election by Default, 2002 (open access)

France: Election by Default, 2002

None
Date: June 27, 2002
Creator: Gallis, Paul E.
Object Type: Report
System: The UNT Digital Library
Friction-induced structural transformations of DLC coatings under different atmospheres. (open access)

Friction-induced structural transformations of DLC coatings under different atmospheres.

The structural transformations that occur in diamondlike carbon coatings with increasing hydrogen content have been investigated by Raman spectroscopy, transmission electron microscopy, electron diffraction, and electron-energy-loss spectroscopy. Friction tests were performed with uncoated steel balls against coated substrates at contact stresses of 1 GPa in ambient air (relative humidity = 30 - 40%), dry air (relative humidity < 1%), and dry nitrogen (< 1%). The lowest friction coefficient (f < 0.02) was obtained for the most hydrogenated sample in dry nitrogen, where the formation of a third-body layer was observed on the steel surface. Raman spectra obtained from the counterfaces after sliding in humid and dry air revealed a remarkable increase and narrowing of the ''D'' and ''G'' peaks with decreasing humidity. Analysis of peak positions and I(D)/I(G) ratios pointed to an increasing order and an enlargement of the sp{sup 2} clusters under friction. The shape and position of the carbon K-edge spectra for the transfer layer are affected the same way, although evidence of extended graphite layer formation was not observed. Development of these differing trends was correlated with the hydrogen-to-carbon ratio of the gas precursor used during the synthesis and with the type of surrounding atmosphere.
Date: June 27, 2002
Creator: Sanchez-Lopez, J. C.; Erdemir, A.; Donnet, C. & Rojas, T. C.
Object Type: Article
System: The UNT Digital Library
Hydrogen Storage Properties of Lithium Aluminohydride Modified by Dopants and Mechanochemistry (open access)

Hydrogen Storage Properties of Lithium Aluminohydride Modified by Dopants and Mechanochemistry

Alkali metal aluminohydrides have high potential as solid hydrogen storage materials. They have been known for their irreversible dehydrogenation process below 100 atm until Bogdanovic et al succeeded in the re-hydrogenation of NaAlH{sub 4} below 70 atm. They achieved 4 wt.% H{sub 2} reversible capacity by doping NaAlH{sub 4} with Ti and/or Fe organo-metallic compounds as catalysts. This suggests that other alkali and, possibly alkaline earth metal aluminohydrides can be used for reversible hydrogen storage when modified by proper dopants. In this research, Zr{sub 27}Ti{sub 9}Ni{sub 38}V{sub 5}Mn{sub 16}Cr{sub 5}, LaNi{sub 4.85}Sn{sub 0.15}, Al{sub 3}Ti, and PdCl{sub 2} were combined with LiAlH{sub 4} by ball-milling to study whether or not LiAlH{sub 4} is capable to both absorb and desorb hydrogen near ambient conditions. X-ray powder diffraction, differential thermal analysis, and scanning electron microscopy were employed for sample characterizations. All four compounds worked as catalysts in the dehydrogenation reactions of both LiAlH{sub 4} and Li{sub 3}AlH{sub 6} by inducing the decomposition at lower temperature. However, none of them was applicable as catalyst in the reverse hydrogenation reaction at low to moderate hydrogen pressure.
Date: June 27, 2002
Creator: Hosokawa, Ketia
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Impact of actinide removal on waste disposal in a geologic repository. (open access)

Impact of actinide removal on waste disposal in a geologic repository.

The presence of actinides in spent fuel destined for a geologic repository such as the proposed Yucca Mountain Repository causes a substantial long term heat load, causes the radiotoxicity of the waste to remain high for tens of thousands of years, and contributes significantly to the long-term dose rate once waste packages begin to fail. Examples, mostly based on the current design of the proposed repository, are considered to illustrate the potential impact of actinide removal on each of these factors. The analyses show that removal of 90 to 99% of the actinides may significantly increase in the capacity of a repository. In addition, the radiotoxicity of the waste may be reduced to a value less than that of the uranium ore from which the fuel was manufactured within the 10,000-year regulatory period. For example, removal of 99.9% of the actinides reduces the radiotoxicity to a level less than that of the original ore in less than 400 years. Finally, removal of 99% of the actinides could reduce the peak long-term dose rate, estimated to occur after about 270,000 years, by as much as a factor of 60.
Date: June 27, 2002
Creator: Morris, E. E.; Bauer, T. H.; Fanning, T. H. & Wigeland, R. A.
Object Type: Article
System: The UNT Digital Library
Implementation of MPICH on Top of MP{_}Lite (open access)

Implementation of MPICH on Top of MP{_}Lite

The goal of this thesis is to develop a new Channel Interface device for the MPICH Implementation of the MPI (Message Passing Interface) standard using MP{_}Lite. MP{_}Lite is a lightweight message-passing library that is not a full MPI implementation, but offers high performance MPICH (Message Passing Interface CHameleon) is a full implementation of the MPI standard that has the p4 library as the underlying communication device for TCP/IP networks. By integrating MP{_}Lite as a Channel Interface device in MPICH, a parallel programmer can utilize the full MPI implementation of MPICH as well as the high bandwidth offered by MP{_}Lite. There are several layers in the MPICH library where one can tie a new device. The Channel Interface is the lowest layer that requires very few functions to add a new device. By attaching MP{_}Lite to MPICH at the lowest level, the Channel Interface, almost all of the performance of the MP{_}Lite library can be delivered to the applications using MPICH. MP{_}Lite can be implemented either as a blocking or a non-blocking Channel Interface device. The performance was measured on two separate test clusters, the PC and the Alpha miniclusters, having Gigabit Ethernet connections. The PC cluster has two 1.8 GHz …
Date: June 27, 2002
Creator: Selvarajan, Shoba
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Investigation of Emulsion Formation in Solvent Washing in the Caustic-Side Solvent Extraction (CSSX) Process (open access)

Investigation of Emulsion Formation in Solvent Washing in the Caustic-Side Solvent Extraction (CSSX) Process

The effects on phase separation and emulsion formation of variables present in the caustic washing of solvent in the caustic-side solvent extraction process have been investigated. The evaluation program was performed in two experiments; results of the first experiment were used to determine conditions for the second test. In the first experiment, the effects of solvent degradation product concentrations (4-sec-butylphenol and dioctylamine), wash solution NaOH concentration, and solvent-to-wash solution volume ratio (O:A) on phase separation were examined. Phase separation performance was quantified in terms of the dimensionless dispersion number, which is also a variable used in the prediction of centrifugal contactor performance by computational means. In the second experiment, phase separation performance in a 5-cm centrifugal contactor was investigated as a function of contactor speed, aqueous-phase NaOH concentration, and solvent-to-wash volume ratio. Separation performance was quantified in terms of the maximum throughput that could be achieved without resulting in >1% contamination of either effluent phase with the opposing phase. Results of the first experiment indicated that none of the variables considered affected phase separation performance at a 95% significance level and that dioctylamine concentration was the only single factor that affected phase separation at a 90% significance level. The results …
Date: June 27, 2002
Creator: Birdwell, JR.J.F.
Object Type: Report
System: The UNT Digital Library
Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System (open access)

Length Scale Correlations of Cellular Microstructures in Directionally Solidified Binary System

In a cellular array, a range of primary spacing is found to be stable under given growth conditions. Since a strong coupling of solute field exists between the neighboring cells, primary spacing variation should also influence other microstructure features such as cell shape and cell length. The existence of multiple solutions is examined in this study both theoretically as well as experimentally. A theoretical model is developed that identifies and relates four important microstructural lengths, which are found to be primary spacing, tip radius, cell width and cell length. This general microstructural relationship is shown to be valid for different cells in an array as well as for other cellular patterns obtained under different growth conditions. The unique feature of the model is that the microstructure correlation does not depend on composition or growth conditions since these variables scale microstructural lengths to satisfy the relationship obtained in this study. Detailed directional solidification experimental studies have been carried out in the succinonitrile-salol system to characterize and measure these four length scales. Besides the validation of the model, experimental results showed additional scaling laws to be present. In the regime where only a cellular structure is formed, the shape of the cell, …
Date: June 27, 2002
Creator: Shen, Yunxue
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Low Temperature Cryocooler Regenerator Materials (open access)

Low Temperature Cryocooler Regenerator Materials

There are four important factors which influence the magnitude of the magnetic heat capacity near the magnetic ordering transition temperature. These include the theoretical magnetic entropy, the deGennes factor, crystalline electric field, and the RKKY (Ruderman-Kittel-Kasuya-Yosida) interaction. The lattice contribution to the heat capacity also needs to be considered since it is the sum of the lattice and magnetic contributions which give rise to the heat capacity maxima. The lattice heat capacity depends on the chemical composition, crystal structure and temperature. As a result, one can obtain large changes in the heat capacity maxima by alloying. Several ternary intermetallic systems have been examined in light of these criteria. A number of deviations from the expected behaviors have been found and are discussed.
Date: June 27, 2002
Creator: Gschneidner, K. A.; Pecharsky, A. O. & Pecharsky, V. K.
Object Type: Article
System: The UNT Digital Library
Managed Care and State External Review Statutes (open access)

Managed Care and State External Review Statutes

None
Date: June 27, 2002
Creator: Welborn, Angie A.
Object Type: Report
System: The UNT Digital Library
The Mechanical Properties of ALCA PlusTM Cast Aluminum Amplifier Top Plates (open access)

The Mechanical Properties of ALCA PlusTM Cast Aluminum Amplifier Top Plates

The amplifier top plates are monolithic, cast aluminum structures from which the amplifier frame assembly units (FAUs), and the line-replaceable flash lamp units (LRUs) inside them, are hung on the support rails in the laser bays. When fully assembled, each plate must support a static weight of 10,600 or 16,000 pounds, depending upon whether two or three loaded FAUs are attached. The top plates are fabricated from ''ALCA Plus{trademark}'', a zinc-containing aluminum casting alloy similar in composition to some standard alloys in the 7000-series. For electrical reasons, all of the plate with the exception of the support ''ears'', is encased in epoxy as shown in Figure 1. The nominal chemistry of the aluminum alloy is summarized in Table 1 and the nominal mechanical characteristics are summarized in Table 2. For comparison, wrought alloys of similar composition in the 7000-series have ultimate strengths of approximately 33-76 ksi and elongations of 11-17%, depending upon the temper.
Date: June 27, 2002
Creator: Biltoft, P; Gourdin, W H; Sanchez, R J & Shen, T H
Object Type: Report
System: The UNT Digital Library