rSUGRA: Putting Nonuniversal Gaugino Masses on the (W)MAP (open access)

rSUGRA: Putting Nonuniversal Gaugino Masses on the (W)MAP

In this talk, we investigate the relic density and direct detection prospects of rSUGRA, a simple paradigm for supersymmetry breaking that allows for nonuniversal gaugino masses. We present updated plots reflecting the latest cosmological measurements from WMAP.
Date: June 17, 2003
Creator: Birkedal-Hansen, Andreas
Object Type: Article
System: The UNT Digital Library
Repair of a Melter Pour Spout Using an Expanding Ring (open access)

Repair of a Melter Pour Spout Using an Expanding Ring

An expanding ring was developed that provided remote repair of the pour spout for a radioactive waste vitrification melter. This passive device used gas pressure to expand a metal ring against the irregularly shaped pour spout wall. Laboratory modeling and testing were performed for proof of concept and optimization before final design and field deployment. The ring expanded radially more than 4.8 mm and successfully repaired the melter pour spout allowing continued glass pouring operation.
Date: June 17, 2003
Creator: Imrich, K. J.
Object Type: Article
System: The UNT Digital Library
Jet Breakup and Spray Formation in a Diesel Engine (open access)

Jet Breakup and Spray Formation in a Diesel Engine

The breakup of injected fuel into spray is of key interest to the design of a fuel efficient, nonpolluting diesel engine. We report preliminary progress on the numerical simulation of diesel fuel injection spray with the front tracking code FronTier. Our simulation design is set to match experiments at ANL, and our present agreement is semi-quantitative. Future efforts will include mesh refinement studies, which will better model the turbulent flow.
Date: June 17, 2003
Creator: Glimm, J.; Li, X.; Kim, M. N.; Oh, W.; Marchese, A.; Samulyak, R. et al.
Object Type: Article
System: The UNT Digital Library
Sludge Batch 3 Simulant Flowsheet Studies: Phase II SRAT/SME Results (open access)

Sludge Batch 3 Simulant Flowsheet Studies: Phase II SRAT/SME Results

The Savannah River Technology Center (SRTC) - Immobilization Technology Section (ITS) was requested to perform simulant bench-scale flowsheet studies to qualify Sludge Batch 3 (SB3), the next sludge batch to be processed at the Defense Waste Processing Facility (DWPF). Simulant flowsheet runs have been performed for every sludge batch that has been qualified for DWPF processing to date. SB3 will consist primarily of Tank 7 sludge, but will also contain transfers from other tanks and processes at the SRS and other materials not considered typical for DWPF processing. Projections also indicate that SB3 may contain higher than previously observed levels of noble metals. Over the last year, SRTC has focused significant effort on studies to understand the behavior of SB3 and to evaluate any necessary process changes.
Date: June 17, 2003
Creator: Herman, C. C.
Object Type: Report
System: The UNT Digital Library
Measurements of field decay and snapback effect on Tevatron dipole magnets (open access)

Measurements of field decay and snapback effect on Tevatron dipole magnets

The performance of Fermilab's Tevatron accelerator, currently in its Run II stage, is degraded by beam loss and emittance dilution during ramping from injection to collision energy. This could be related in part to insufficient compensation of dynamic effects such as the decay of the magnetic field in the dipoles during the dwell at injection and the following so-called snapback during the first few seconds of the energy ramp. The two effects are closely related and depend on the powering history of the magnets. Dynamic effects, which were originally discovered at the Tevatron, were investigated on Tevatron magnets in various past measurement campaigns in the 1980s and later in 1996. This paper reports on the most recent measurements performed on an additional set of Tevatron magnets.
Date: June 17, 2003
Creator: al., Gueorgui V Velev et
Object Type: Article
System: The UNT Digital Library
Prospects for next generation long-baseline oscillation experiments (open access)

Prospects for next generation long-baseline oscillation experiments

This document describes some of the exciting possibilities for the next steps in the field of long baseline neutrino oscillation measurements. Because the primary goals of these new experiments are so different from those of the current generation, one cannot simply increase the running time or detector mass of the current programs. There are several new strategies which have been discussed for taking the next steps: sometimes the detectors, sometimes the beamlines, and sometimes both are radically different from what is now in place.
Date: June 17, 2003
Creator: Harris, Deborah A
Object Type: Article
System: The UNT Digital Library
Multigrid Particle-in-cell Simulations of Plasma Microturbulence (open access)

Multigrid Particle-in-cell Simulations of Plasma Microturbulence

A new scheme to accurately retain kinetic electron effects in particle-in-cell (PIC) simulations for the case of electrostatic drift waves is presented. The splitting scheme, which is based on exact separation between adiabatic and on adiabatic electron responses, is shown to yield more accurate linear growth rates than the standard df scheme. The linear and nonlinear elliptic problems that arise in the splitting scheme are solved using a multi-grid solver. The multi-grid particle-in-cell approach offers an attractive path, both from the physics and numerical points of view, to simulate kinetic electron dynamics in global toroidal plasmas.
Date: June 17, 2003
Creator: Lewandowski, J. L. V.
Object Type: Report
System: The UNT Digital Library
Technetium Eluate Evaporation Solubility and Precipitation Performance (open access)

Technetium Eluate Evaporation Solubility and Precipitation Performance

The baseline flowsheet for low activity waste in the Hanford River Protection Project Waste Treatment Plant includes pretreatment of supernatant by removing technetium using ion exchange. The primary purpose of this work is validation of the predictions of the Tc eluate computer model.
Date: June 17, 2003
Creator: Johnson, J. D.
Object Type: Report
System: The UNT Digital Library
Cesium Eluate Semi-Batch Evaporation Performance (open access)

Cesium Eluate Semi-Batch Evaporation Performance

The baseline flowsheet for low activity waste (LAW) in the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) includes pretreatment of supernatant by removing cesium using ion exchange. When the ion exchange column is loaded, the cesium will be eluted with a 0.5M nitric acid (HNO3) solution to allow the column to be conditioned for re-use. The cesium eluate solution will then be concentrated in a vacuum evaporator to minimize storage volume and to recycle HNO3.
Date: June 17, 2003
Creator: Pierce, Robert A.
Object Type: Report
System: The UNT Digital Library
Summary of Data and Steps for Processing the 1997-2001 SRS Meteorological Database (open access)

Summary of Data and Steps for Processing the 1997-2001 SRS Meteorological Database

Every five years since the mid-1970s DOE has requested an update on the meteorological conditions at SRS in order to provide dose calculations for accident or routine release scenarios for onsite and offsite populations. The meteorological database includes wind speed, wind direction, temperature, dew point, and horizontal and vertical turbulence intensities. The two most recent databases prior to the current one were completed in 1998 for the time period 1992-96 (Weber, 1998) and one for 1987-91 (Parker, et. al., 1992). The current database covers the period 1997-2001. The advantage of updating the database every five years is that meteorological observations are steadily growing more complete and less subject to errors with the implementation of better electronic data archiving software and hardware, and improved data quality assurance procedures. Also, changes in the region's climate may be manifest.
Date: June 17, 2003
Creator: Weber, A. H.
Object Type: Report
System: The UNT Digital Library
Challenges of Non-Destructive Assay Waste Measurement (open access)

Challenges of Non-Destructive Assay Waste Measurement

Historically, the Savannah River Site (SRS) routinely produced special nuclear material (SNM), which provided stable measurement conditions for the non-destructive assay (NDA) methods. However, the main mission of SRS has changed from the production of SNM to the processing of waste and material stabilization. Currently, the purpose of processing is to recover the SNM from the waste and stabilization materials, much of which is from other DOE facilities. These missions are usually of a short duration, but require non-destructive assay (NDA) accountability measurements on materials of varying composition and geometric configuration. These missions usually have cost and time constraints, which sometimes require re-application of existing NDA methods to waste measurements. Usually, each new material or re-application of the NDA method to a different SNM campaign requires new standards and timely re-calibration of the method. These constraints provide numerous challenges for the NDA methods, particularly in the area of measurement uncertainty. This paper will discuss the challenges of these situations, mainly from a measurement and statistical point of view and provide some possible solutions to the problems encountered. Specific examples will be discussed for the segmented gamma scanner (SGS), neutron multiplicity counter (NMC) and passive neutron coincidence counter (PNCC), which are …
Date: June 17, 2003
Creator: Shull, A.H.
Object Type: Article
System: The UNT Digital Library
Modern Trends in Induction Accelerator Technology (open access)

Modern Trends in Induction Accelerator Technology

None
Date: June 17, 2003
Creator: Caporaso, G J
Object Type: Article
System: The UNT Digital Library
Molecular Dynamics Study of Void Growth and Dislocations in Dynamic Fracture of FCC and BCC Metals (open access)

Molecular Dynamics Study of Void Growth and Dislocations in Dynamic Fracture of FCC and BCC Metals

Void growth with concomitant dislocation formation has been studied in single crystal face-centered-cubic and body-centered-cubic metals using molecular dynamics method with Embedded-Atom and Finnis-Sinclair potentials for copper and tantalum, respectively. We have concentrated on the quantitative analysis of the void shape evolution, on the structure of dislocations, which emerge from the void, and on the continuum measures such as plastic strain. The effects of strain-rate, differences between lattice structures, and loading conditions as uniaxial, biaxial, and triaxial expansion on the shape of the void and on the dislocations have been investigated.
Date: June 17, 2003
Creator: Seppala, E T; Belak, J & Rudd, R E
Object Type: Article
System: The UNT Digital Library
Electron Transport Workshop September 9-11, 2002 (open access)

Electron Transport Workshop September 9-11, 2002

None
Date: June 17, 2003
Creator: Edwards, J.; Glenzar, S.; Alley, E.; Town, R.; Braun, D.; Kruer, B. et al.
Object Type: Report
System: The UNT Digital Library
Percolation Fractal Dimension in Scattering Line Shapes of the Random-Field Ising Model (open access)

Percolation Fractal Dimension in Scattering Line Shapes of the Random-Field Ising Model

Neutron scattering and simulation line shape data show evidence for fractal structure from spanning clusters in the d = 2 and d = 3 random-field Ising models as realized in dilute antiferromagnets.
Date: June 17, 2003
Creator: Ye, F.; Matsuda, M.; Katano, S.; Yoshizawa, H.; Belanger, D. P.; Seppala, E. T. et al.
Object Type: Article
System: The UNT Digital Library
Neutron Detection with Mercuric Iodide (open access)

Neutron Detection with Mercuric Iodide

Mercuric iodide is a high-density, high-Z semiconducting material useful for gamma ray detection. This makes it convertible to a thermal neutron detector by covering it with a boron rich material and detecting the 478 keV gamma rays resulting from the {sup 10}B(n, {alpha}){sup 7}Li* reaction. However, the 374 barn thermal capture cross section of {sup nat}Hg, makes the detector itself an attractive absorber, and this has been exploited previously. Since previous work indicates that there are no low-energy gamma rays emitted in coincidence with the 368 keV capture gamma from the dominant {sup 199}Hg(n, {gamma}){sup 200}Hg reaction, only the 368 keV capture gamma is seen with any efficiency a relatively thin (few mm) detector. In this paper we report preliminary measurements of neutrons via capture reactions in a bare mercuric iodide crystal and a crystal covered in {sup 10}B-loaded epoxy. The covered detector is an improvement over the bare detector because the presence of both the 478 and 368 keV gamma rays removes the ambiguity associated with the observation of only one of them. Pulse height spectra, obtained with and without lead and cadmium absorbers, showed the expected gamma rays and demonstrated that they were caused by neutrons.
Date: June 17, 2003
Creator: Bell, Z. A.
Object Type: Report
System: The UNT Digital Library
All Not Fit to Breed: Survivors of America's First Eugenics Movement (open access)

All Not Fit to Breed: Survivors of America's First Eugenics Movement

This report summarizes research conducted in 2001 and 2002 under the above grant entitled " All Not Fit to Breed: Survivors of America's First Eugenics Movement"
Date: June 17, 2003
Creator: Bishop, Mary C.
Object Type: Report
System: The UNT Digital Library