Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV (open access)

Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV

Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse momentum range 1.2 < p{sub T} < 3.0 GeV/c is measured to be 1.19 {+-} 0.05(stat) {+-} 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + {bar p})/h in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.
Date: September 16, 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
Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction from 5.9-8.7 MeV (open access)

Measurement of Cross Sections for the 63Cu(alpha,gamma)67Ga Reaction from 5.9-8.7 MeV

None
Date: September 16, 2004
Creator: Basunia, M. S.; Norman, E. B.; Shugart, H. A.; Smith, A. R.; Dolinski, M. J. & Quiter, B. J.
Object Type: Article
System: The UNT Digital Library
A Microfluidic Hydrogen Generator for Fuel Cell Applications (open access)

A Microfluidic Hydrogen Generator for Fuel Cell Applications

A study of the reaction rates, heat and mass transfer and flow, in and from a methanol reforming catalytic micro-reactor fabricated on a silicon wafer is presented. Comparison of computed and measured conversion efficiencies are shown to be favorable.
Date: September 16, 2003
Creator: Benett, W.; Chung, J.; Greif, R.; Grigoropoulos, C. P.; Harvey, C.; Havstad, M. et al.
Object Type: Article
System: The UNT Digital Library
Bounds and self-consistent estimates for elastic constants of random polycrystals with hexagonal, trigonal, and tetragonal symmetries (open access)

Bounds and self-consistent estimates for elastic constants of random polycrystals with hexagonal, trigonal, and tetragonal symmetries

Peselnick, Meister, and Watt have developed rigorous methods for bounding elastic constants of random polycrystals based on the Hashin-Shtrikman variational principles. In particular, a fairly complex set of equations that amounts to an algorithm has been presented previously for finding the bounds on effective elastic moduli for polycrystals having hexagonal, trigonal, and tetragonal symmetries. The more analytical approach developed here, although based on the same ideas, results in a new set of compact formulas for all the cases considered. Once these formulas have been established, it is then straightforward to perform what could be considered an analytic continuation of the formulas (into the region of parameter space between the bounds) that can subsequently be used to provide self-consistent estimates for the elastic constants in all cases. These self-consistent estimates are easily shown (essentially by construction) to lie within the bounds for all the choices of crystal symmetry considered. Estimates obtained this way are quite comparable to those found by the Gubernatis and Krumhansl CPA (coherent potential approximation), but do not require any computations of scattering coefficients.
Date: September 16, 2004
Creator: Berger, E. L.
Object Type: Article
System: The UNT Digital Library
HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 4th QUARTER 2008 MILESTONE REPORT (open access)

HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 4th QUARTER 2008 MILESTONE REPORT

This milestone has been met. In the previous quarter (3rd quarter FY2008), the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) completed the new experimental target chamber facility for future Warm Dense Matter (WDM) experiments [1]. The target chamber is operational and target experiments are now underway, using beams focused by a final focus solenoid and compressed by an improved bunching waveform. Initial experiments have demonstrated the capability of the Neutralized Drift Compression Experiment (NDCX) beam to heat bulk matter in target foils. The experiments have focused on tuning and characterizing the NDCX beam in the target chamber, implementing the target assembly, and implementing target diagnostics in the target chamber environment. We have completed a characterization and initial optimization of the compressed and uncompressed NDCX beam entering the target chamber. The neutralizing plasma has been significantly improved to increase the beam neutralization in the target chamber. Preliminary results from recent beam tests of a gold cone for concentrating beam energy on target are encouraging and indicate the potential to double beam intensity on target. Other advantages of the cone include the large amount of neutralizing secondary electrons expected from the grazing incidence at the cone walls, and the shielding of …
Date: September 16, 2008
Creator: Bieniosek, F. M.; Anders, A.; Barnard, J. J.; Dickinson, M. R.; Greenway, W.; Henestroza, E. et al.
Object Type: Report
System: The UNT Digital Library
Final Report for 'ParSEC-Parallel Simulation of Electron Cooling" (open access)

Final Report for 'ParSEC-Parallel Simulation of Electron Cooling"

The Department of Energy has plans, during the next two or three years, to design an electron cooling section for the collider ring at RHIC (Relativistic Heavy Ion Collider) [1]. Located at Brookhaven National Laboratory (BNL), RHIC is the premier nuclear physics facility. The new cooling section would be part of a proposed luminosity upgrade [2] for RHIC. This electron cooling section will be different from previous electron cooling facilities in three fundamental ways. First, the electron energy will be 50 MeV, as opposed to 100's of keV (or 4 MeV for the electron cooling system now operating at Fermilab [3]). Second, both the electron beam and the ion beam will be bunched, rather than being essentially continuous. Third, the cooling will take place in a collider rather than in a storage ring. Analytical work, in combination with the use and further development of the semi-analytical codes BETACOOL [4,5] and SimCool [6,7] are being pursued at BNL [8] and at other laboratories around the world. However, there is a growing consensus in the field that high-fidelity 3-D particle simulations are required to fully understand the critical cooling physics issues in this new regime. Simulations of the friction coefficient, using the …
Date: September 16, 2005
Creator: Bruhwiler, David L
Object Type: Report
System: The UNT Digital Library
Ion energy distribution functions of vacuum arc plasmas (open access)

Ion energy distribution functions of vacuum arc plasmas

The velocity distribution function of vacuum arc ions can be measured by a time-of-flight technique similar to a method originally proposed by Yushkov. The measuring principle makes use of the well-justified assumption that the ion drift velocity from the cathode spot region to a collector is approximately constant. It is shown that the negative time derivative of the collector current is directly proportional to the ion distribution function provided that the time-averaged source intensity (i.e., emission of ions from cathode spots) is constant until the arc is rapidly switched off. In the experiment, arc termination took about 700 ns, which is much faster than the decay of the ion current measured at the collector placed in more than 2 meters distance from the cathode. The experimental distribution functions for most cathode materials show one large peak with a tail and one or more small peaks at higher ion velocities. The distribution functions for some other materials exhibit several peaks. No conclusive answer can be given about the nature of these peaks. Arguments are presented that the peaks are not caused by different charge states or plasma contamination but rather due to insufficiently averaged source fluctuations and/or acceleration by plasma instabilities.
Date: September 16, 2002
Creator: Byon, Eungsun & Anders, Andre
Object Type: Article
System: The UNT Digital Library
Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough. (open access)

Global Analysis of Heat Shock Response in Desulfovibrio vulgaris Hildenborough.

Desulfovibrio vulgaris Hildenborough belongs to a class ofsulfate-reducing bacteria (SRB) and is found ubiquitously in nature.Given the importance of SRB-mediated reduction for bioremediation ofmetal ion contaminants, ongoing research on D. vulgaris has been in thedirection of elucidating regulatory mechanisms for this organism under avariety of stress conditions. This work presents a global view of thisorganism's response to elevated growth temperature using whole-celltranscriptomics and proteomics tools. Transcriptional response (1.7-foldchange or greater; Z>1.5) ranged from 1,135 genes at 15 min to 1,463genes at 120 min for a temperature up-shift of 13oC from a growthtemperature of 37oC for this organism and suggested both direct andindirect modes of heat sensing. Clusters of orthologous group categoriesthat were significantly affected included posttranslationalmodifications; protein turnover and chaperones (up-regulated); energyproduction and conversion (down-regulated), nucleotide transport,metabolism (down-regulated), and translation; ribosomal structure; andbiogenesis (down-regulated). Analysis of the genome sequence revealed thepresence of features of both negative and positive regulation whichincluded the CIRCE element and promoter sequences corresponding to thealternate sigma factors ?32 and ?54. While mechanisms of heat shockcontrol for some genes appeared to coincide with those established forEscherichia coli and Bacillus subtilis, the presence of unique controlschemes for several other genes was also evident. Analysis of proteinexpression levels using …
Date: September 16, 2005
Creator: Chhabra, S. R.; He, Q.; Huang, K. H.; Gaucher, S. P.; Alm, E. J.; He, Z. et al.
Object Type: Article
System: The UNT Digital Library
2004 Inorganic Chemistry Gordon Research Conference - July 18-23, 2004 (open access)

2004 Inorganic Chemistry Gordon Research Conference - July 18-23, 2004

The Gordon Research Conference (GRC) on 2004 Inorganic Chemistry Gordon Research Conference - July 18-23, 2004 was held at Salve Regina College, July 18-23, 2004. The Conference was well-attended with 110 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, 'free time' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.
Date: September 16, 2005
Creator: Clark, David
Object Type: Article
System: The UNT Digital Library
HANFORD MEDIUM-LOW CURIE WASTE PRETREATMENT ALTERNATIVES PROJECT FRACTIONAL CRYSTALLIZATION PILOT SCALE TESTING FINAL REPORT (open access)

HANFORD MEDIUM-LOW CURIE WASTE PRETREATMENT ALTERNATIVES PROJECT FRACTIONAL CRYSTALLIZATION PILOT SCALE TESTING FINAL REPORT

The Fractional Crystallization Pilot Plant was designed and constructed to demonstrate that fractional crystallization is a viable way to separate the high-level and low-activity radioactive waste streams from retrieved Hanford single-shell tank saltcake. The focus of this report is to review the design, construction, and testing details of the fractional crystallization pilot plant not previously disseminated.
Date: September 16, 2008
Creator: DL, HERTING
Object Type: Report
System: The UNT Digital Library
Practical superconductor development for electrical power applications - quarterly report for the period ending June 30, 2003. (open access)

Practical superconductor development for electrical power applications - quarterly report for the period ending June 30, 2003.

This is a multiyear experimental research program that focuses on improving relevant material properties of high-critical temperature (T{sub c}) superconductors and developing fabrication methods that can be transferred to industry for production of commercial conductors. The development of teaming relationships through agreements with industrial partners is a key element of the Argonne National Laboratory (ANL) program. A transport critical current density (J{sub c}) of 1.2 x 10{sup 6} A/cm{sup 2} was measured with a sample made with the standard inclined substrate deposition (ISD) architecture. Recent results are described from a study of SrRuO{sub 3} (SRO), a potential alternative buffer layer in coated conductors made by the inclined substrate deposition (ISD) method. Basic features of Raman microscopy are also discussed, and results are presented from a detailed Raman microprobe study of a 1.25-m-long YBCO coated conductor specimen produced at Oak Ridge National Laboratory (ORNL). Strain tolerance data are presented as a function of YBCO thickness for coated conductors with the standard ISD architecture.
Date: September 16, 2003
Creator: Dorris, S. E.
Object Type: Report
System: The UNT Digital Library
Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities (open access)

Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.
Date: September 16, 2009
Creator: Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim et al.
Object Type: Article
System: The UNT Digital Library
Space Debris-de-Orbiting by Vaporization Impulse using Short Pulse Laser (open access)

Space Debris-de-Orbiting by Vaporization Impulse using Short Pulse Laser

Space debris constitutes a significant hazard to low earth orbit satellites and particularly to manned spacecraft. A quite small velocity decrease from vaporization impulses is enough to lower the perigee of the debris sufficiently for atmospheric drag to de-orbit the debris. A short pulse (picosecond) laser version of the Orion concept can accomplish this task in several years of operation. The ''Mercury'' short pulse Yb:S-FAP laser being developed at LLNL for laser fusion is appropriate for this task.
Date: September 16, 2003
Creator: Early, J; Bibeau, C & Claude, P
Object Type: Article
System: The UNT Digital Library
Radiochemical Analyses of the Filter Cake, Granular Activated Carbon, and Treated Ground Water from the DTSC Stringfellow Superfund Site Pretreatment Plant (open access)

Radiochemical Analyses of the Filter Cake, Granular Activated Carbon, and Treated Ground Water from the DTSC Stringfellow Superfund Site Pretreatment Plant

The Department of Toxic Substance Control (DTSC) requested that Lawrence Livermore National Laboratory (LLNL) evaluate the treatment process currently employed at the Department's Stringfellow Superfund Site Pretreatment Plant (PTP) site to determine if wastes originating from the site were properly managed with regards to their radioactivity. In order to evaluate the current management strategy, LLNL suggested that DTSC characterize the effluents from the waste treatment system for radionuclide content. A sampling plan was developed; samples were collected and analyzed for radioactive constituents. Following is brief summary of those results and what implications for waste characterization may be made. (1) The sampling and analysis provides strong evidence that the radionuclides present are Naturally Occurring Radioactive Material (NORM). (2) The greatest source of radioactivity in the samples was naturally occurring uranium. The sample results indicate that the uranium concentration in the filter cake is higher than the Granular Activated Carbon (GAC) samples. (11 -14 and 2-6 ppm respectively). (3) No radiologic background for geologic materials has been established for the Stringfellow site, and comprehensive testing of the process stream has not been conducted. Without site-specific testing of geologic materials and waste process streams, it is not possible to conclude if filter cake …
Date: September 16, 2005
Creator: Esser, B K; McConachie, W; Fischer, R; Sutton, M & Szechenyi, S
Object Type: Report
System: The UNT Digital Library
ASSESSMENT OF RADIONUCLIDES DATABASES IN CAP88 MAINFRAME VERSION 1.0 AND WINDOWS-BASED VERSION 3.0 (open access)

ASSESSMENT OF RADIONUCLIDES DATABASES IN CAP88 MAINFRAME VERSION 1.0 AND WINDOWS-BASED VERSION 3.0

In this study the radionuclide databases for two versions of the Clean Air Act Assessment Package-1988 (CAP88) computer model were assessed in detail. CAP88 estimates radiation dose and the risk of health effects to human populations from radionuclide emissions to air. This program is used by several Department of Energy (DOE) facilities to comply with National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations. CAP88 Mainframe, referred to as Version 1.0 on the Environmental Protection Agency (EPA) website (http://www.epa.gov/radiation/assessment/CAP88/), was the very first CAP88 version released in 1988. Some DOE facilities including the Savannah River Site still employ this version (1.0) while others use the more user-friendly personal computer Windows-based Version 3.0 released in December 2007. Version 1.0 uses the program RADRISK based on International Commission on Radiological Protection (ICRP) Publication 30 as its radionuclide database. Version 3.0 uses half-life, dose and risk factor values based on Federal Guidance Report 13. Differences in these values could cause different results for the same input exposure data (same scenario), depending on which version of CAP88 is used. Consequently, the differences between the two versions are being assessed in detail at Savannah River National Laboratory. The version 1.0 and 3.0 database files contain …
Date: September 16, 2008
Creator: Farfan, E.; Lee, P.; Jannik, T. & Donnelly, E.
Object Type: Article
System: The UNT Digital Library
CHARACTERIZATION OF PLASTICALLY-INDUCED STRUCTURAL CHANGES IN A Zr-BASED BULK METALLIC GLASS USING POSITRON ANNIHILATION SPECTROCOPY (open access)

CHARACTERIZATION OF PLASTICALLY-INDUCED STRUCTURAL CHANGES IN A Zr-BASED BULK METALLIC GLASS USING POSITRON ANNIHILATION SPECTROCOPY

Flow in metallic glasses is associated with stress-induced cooperative rearrangements of small groups of atoms involving the surrounding free volume. Understanding the details of these rearrangements therefore requires knowledge of the amount and distribution of the free volume and how that distribution evolves with deformation. The present study employs positron annihilation spectroscopy to investigate the free volume change in Zr{sub 58.5}Cu{sub 15.6}Ni{sub 12.8}Al{sub 10.3}Nb{sub 2.8} bulk metallic glass after inhomogeneous plastic deformation by cold rolling and structural relaxation by annealing. Results indicate that the size distribution of open volume sites is at least bimodal. The size and concentration of the larger group, identified as flow defects, changes with processing. Following initial plastic deformation the size of the flow defects increases, consistent with the free volume theory for flow. Following more extensive deformation, however, the size distribution of the positron traps shifts, with much larger open volume sites forming at the expense of the flow defects. This suggests that a critical strain is required for flow defects to coalesce and form more stable nanovoids, which have been observed elsewhere by high resolution TEM. Although these results suggest the presence of three distinct open volume size groups, further analysis indicates that all …
Date: September 16, 2005
Creator: Flores, K M; Kanungo, B P; Glade, S C & Asoka-Kumar, P
Object Type: Article
System: The UNT Digital Library
Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction (open access)

Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction

On July 22, 23, 24, 2003, three one day workshops were held in Gaithersburg, Maryland. Each was attended by about 30 computational biologists, mathematicians, and computer scientists who were experts in the respective workshop areas The first workshop discussed the data infrastructure needs for the Genomes to Life (GTL) program with the objective to identify gaps in the present GTL data infrastructure and define the GTL data infrastructure required for the success of the proposed GTL facilities. The second workshop discussed the modeling and simulation needs for the next phase of the GTL program and defined how these relate to the experimental data generated by genomics, proteomics, and metabolomics. The third workshop identified emerging technical challenges in computational protein structure prediction for DOE missions and outlining specific goals for the next phase of GTL. The workshops were attended by representatives from both OBER and OASCR. The invited experts at each of the workshops made short presentations on what they perceived as the key needs in the GTL data infrastructure, modeling and simulation, and structure prediction respectively. Each presentation was followed by a lively discussion by all the workshop attendees. The following findings and recommendations were derived from the three workshops. …
Date: September 16, 2003
Creator: Geist, GA
Object Type: Report
System: The UNT Digital Library
X-ray stereo microscopy for investigation of dynamics in soils (open access)

X-ray stereo microscopy for investigation of dynamics in soils

The presented combination of stereo imaging and elemental mapping with soft X-ray microscopy reveals the spatial arrangement of naturally aqueous colloidal systems, e.g. iron oxides in soil colloid clusters. Changes in the spatial arrangement can be induced by manipulating the sample mounted to the X-ray microscope and thus be investigated directly.
Date: September 16, 2008
Creator: Gleber, S.-C.; Sedlmair, J.; Bertilson, M.; von Hofsten, O.; Heim, S.; Guttmann, P. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of High-Temperature Laser-Produced Plasmas Using Thomson Scattering (open access)

Characterization of High-Temperature Laser-Produced Plasmas Using Thomson Scattering

Ultraviolet Thomson scattering has been fielded at the Omega Laser Facility to achieve accurate measurements of the plasma conditions in laser-produced high-temperature plasmas. Recent applications to hohlraum targets that have been filled with CH gas or SiO{sub 2} foams have demonstrated a new high temperature plasma regime of importance to laser-plasma interaction studies in a strongly damped regime such as those occurring in indirect drive inertial confinement fusion experiments. The Thomson scattering spectra show the collective ion acoustic features that fit the theory for two ion species plasmas and from which we infer the electron and ion temperature. We find that the electron temperature scales from 2-4 keV when increasing the heater beam energy into the hohlraum from 8-17 kJ, respectively. Simultaneous measurements of the stimulated Raman scattering from a green 527 nm interaction beam show that the reflectivity decreases from 20% to 1% indicating that this instability is strongly damped at high temperatures. These findings support green laser beams as possible driver option for laser-driven fusion experiments.
Date: September 16, 2005
Creator: Glenzer, S H; Froula, D H; Ross, S; Niemann, C; Meezan, N & Divol, L
Object Type: Article
System: The UNT Digital Library
Collaborative project: research on strongly coupled plasmas. Final technical report for period July 15, 1998--July 14, 2002 (open access)

Collaborative project: research on strongly coupled plasmas. Final technical report for period July 15, 1998--July 14, 2002

The main research accomplishments/findings of the project were the following: (1) Publication of an in-depth review article in Physics of Plasmas on the quasilocalized charge approximation (QLCA) in strongly coupled plasma physics and its application to a variety of Coulomb systems: the model one-component plasma in three and two dimensions, binary ionic mixtures, charged particle bilayers, and laboratory dusty plasmas. (2) In the strongly coupled Coulomb liquid phase, the physical basis of the QLCA, namely, the caging of particles trapped in slowly fluctuating local potential minima, is supported by molecular dynamics simulation of the classical three-dimensional one-component plasma. (3) The QLCA theory, when applied to the analysis of the collective modes in strongly coupled charged particle bilayers, predicts the existence of a remarkable long-wavelength energy gap in the out-of-phase excitation spectrum. More recent theoretical calculations based on the three principal frequency-moment sum rules reveal that the gap persists for arbitrary coupling strengths and over the entire classical to quantum domain all the way down to zero temperature. The existence of the energy gap has now been confirmed in a molecular dynamics simulation of the charged particle bilayer. (4) New compressibility and third-frequency-moment sum rules for multilayer plasmas were formulated and …
Date: September 16, 2002
Creator: Golden, Kenneth I.
Object Type: Report
System: The UNT Digital Library
An Analytical Model for Solute Transport in Unsaturated Flowthrough a Single Fracture and Porous Rock Matrix (open access)

An Analytical Model for Solute Transport in Unsaturated Flowthrough a Single Fracture and Porous Rock Matrix

Exact analytical solutions are presented for solute transport in an unsaturated fracture and porous rock matrix. The problem includes advective transport in the fracture and rock matrix as well as advective and diffusive fracture-matrix exchange. Linear sorption in the fracture and matrix and radioactive decay are also treated. The solution is for steady, uniform transport velocities within the fracture and matrix, but allows for independent specification of each of the velocities. The problem is first solved in terms of the solute concentrations that result from an instantaneous point source. Superposition integrals are then used to derive the solute mass flux at a fixed downstream position from an instantaneous point source and for the solute concentrations that result from a continuous point source. Solutions are derived for cases with the solute source in the fracture and the solute source in the matrix. The analytical solutions are closed-form and are expressed in terms of algebraic functions, exponentials, and error functions. Comparisons between the analytical solutions and numerical simulations, as well as sensitivity studies, are presented. Increased sensitivity to cross-flow and solute source location is found for increasing Peclet number. The numerical solutions are found to compare well with the analytical solutions at …
Date: September 16, 2004
Creator: Houseworth, J.E.
Object Type: Article
System: The UNT Digital Library
General Corrosion and Localized Corrosion of the Drip Shield (open access)

General Corrosion and Localized Corrosion of the Drip Shield

The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).
Date: September 16, 2004
Creator: Hua, F.
Object Type: Report
System: The UNT Digital Library
Layzer type models for pressure driven shells (open access)

Layzer type models for pressure driven shells

Models for the nonlinear instability of finite thickness shells driven by pressure are constructed in the style of Layzer. Equations for both Cartesian and cylindrically convergent/divergent geometries are derived. The resulting equations are appropriate for incompressible shells with unity Atwood number. Predictions from the equations compare well with two-dimensional simulations.
Date: September 16, 2004
Creator: Hurricane, O A
Object Type: Article
System: The UNT Digital Library
Fabrication techniques for septum magnets at the APS. (open access)

Fabrication techniques for septum magnets at the APS.

The design, construction, and installation of pulsed septum magnets for particle accelerators presents many challenges for the magnet engineer. Issues associated with magnet core structure design, component alignment, weldment design, and electrical insulation choices are among those requiring careful attention. The designs of the six septum magnets required for the APS facility have evolved since operation began in 1996. Improvements in the designs have provided better injection/extraction performance parameters and extended the machine reliability to meet the requirements of a world-class, third-generation synchrotron radiation facility. Details of the techniques used to address issues involved in producing septum magnets at the APS are described here to aid magnet engineers in the fabrication of future septum magnets.
Date: September 16, 2002
Creator: Jaski, M.; Thompson, K.; Kim, S.; Friedsam, H.; Toter, W. & Humbert, J.
Object Type: Article
System: The UNT Digital Library