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695 Matching Results
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Head Start Issues in the 108th Congress
This report provides Head Start issues on the 108th congress, a federal program that has provided comprehensive early childhood development services to low-income children since 1965.
Date:
February 26, 2004
Creator:
Melinda, Gish
Object Type:
Report
System:
The UNT Digital Library
Adaptive Sampling for Noisy Problems
The usual approach to deal with noise present in many real-world optimization problems is to take an arbitrary number of samples of the objective function and use the sample average as an estimate of the true objective value. The number of samples is typically chosen arbitrarily and remains constant for the entire optimization process. This paper studies an adaptive sampling technique that varies the number of samples based on the uncertainty of deciding between two individuals. Experiments demonstrate the effect of adaptive sampling on the final solution quality reached by a genetic algorithm and the computational cost required to find the solution. The results suggest that the adaptive technique can effectively eliminate the need to set the sample size a priori, but in many cases it requires high computational costs.
Date:
March 26, 2004
Creator:
Cantu-Paz, E
Object Type:
Article
System:
The UNT Digital Library
NUCLEAR SCIENCE REFERENCES AS A TOOL FOR DATA EVALUATION.
For several decades, the Nuclear Science References database has been maintained as a tool for data evaluators and for the wider pure and applied research community. This contribution will describe the database and recent developments in web-based access.
Date:
September 26, 2004
Creator:
WINCHELL,D. F.
Object Type:
Article
System:
The UNT Digital Library
Electron-Cloud Simulation and Theory for High-Current Heavy-Ion Beams
Stray electrons can arise in positive-ion accelerators for heavy ion fusion or other applications as a result of ionization of ambient gas or gas released from walls due to halo-ion impact, or as a result of secondary- electron emission. We summarize the distinguishing features of electron cloud issues in heavy-ion-fusion accelerators and a plan for developing a self-consistent simulation capability for heavy-ion beams and electron clouds. We also present results from several ingredients in this capability: (1) We calculate the electron cloud produced by electron desorption from computed beam-ion loss, which illustrates the importance of retaining ion reflection at the walls. (2) We simulate of the effect of specified electron cloud distributions on ion beam dynamics. We consider here electron distributions with axially varying density, centroid location, or radial shape, and examine both random and sinusoidally varying perturbations. We find that amplitude variations are most effective in spoiling ion beam quality, though for sinusoidal variations which match the natural ion beam centroid oscillation or breathing mode frequencies, the centroid and shape perturbations can also have significant impact. We identify an instability associated with a resonance between the beam-envelope ''breathing'' mode and the electron perturbation. We estimate its growth rate, which …
Date:
July 26, 2004
Creator:
Cohen, R; Friedman, A; Lund, S; Molvik, A; Lee, E; Azevedo, T et al.
Object Type:
Article
System:
The UNT Digital Library
Automatic Blocking Of QR and LU Factorizations for Locality
QR and LU factorizations for dense matrices are important linear algebra computations that are widely used in scientific applications. To efficiently perform these computations on modern computers, the factorization algorithms need to be blocked when operating on large matrices to effectively exploit the deep cache hierarchy prevalent in today's computer memory systems. Because both QR (based on Householder transformations) and LU factorization algorithms contain complex loop structures, few compilers can fully automate the blocking of these algorithms. Though linear algebra libraries such as LAPACK provides manually blocked implementations of these algorithms, by automatically generating blocked versions of the computations, more benefit can be gained such as automatic adaptation of different blocking strategies. This paper demonstrates how to apply an aggressive loop transformation technique, dependence hoisting, to produce efficient blockings for both QR and LU with partial pivoting. We present different blocking strategies that can be generated by our optimizer and compare the performance of auto-blocked versions with manually tuned versions in LAPACK, both using reference BLAS, ATLAS BLAS and native BLAS specially tuned for the underlying machine architectures.
Date:
March 26, 2004
Creator:
Yi, Q; Kennedy, K; You, H; Seymour, K & Dongarra, J
Object Type:
Article
System:
The UNT Digital Library
Development of LLNL Methodology for Nonnuclear Safety Bases
The objective of this paper is to introduce the process and philosophies used to develop LLNL methodology for performing nonnuclear safety bases. Our former approach needed revision in order to implement the new Work Smart Standard (WSS), 'Safety Basis Requirements for Nonnuclear Facilities at Lawrence Livermore National Laboratory Site Specific Standard' (UCRL-ID-150214), approved in 2003 and revised January, 2004. This work relates directly to the following workshop theme: 'Improvements in Chemical, Biological, and Non-nuclear Safety analysis.' A requirements document, Environmental Safety and Health Manual, Document 3.1 provides safety bases methodology 'how-to' for LLNL personnel. This methodology document had to undergo a major revision, and essentially was completely re-written, since the nonnuclear requirements underwent a major change due to the new standard. The new methodology was based on a graded approach respective to risk level for each hazard type and facility classification. The development process included input from a cross-section of representatives of LLNL organizations at every step in the process. The initial methodology was tested in a pilot project that resulted in completed safety basis analyses and documentation for a major facility at LLNL. Feedback from the pilot was used to refine the methodology. The new methodology promotes a graded …
Date:
April 26, 2004
Creator:
van Warmerdam, C M & Pinkston, D M
Object Type:
Article
System:
The UNT Digital Library
The Albany News (Albany, Tex.), Vol. 128, No. 38, Ed. 1 Thursday, February 26, 2004
Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date:
February 26, 2004
Creator:
Lucas, Melinda L.
Object Type:
Newspaper
System:
The Portal to Texas History
The Albany News (Albany, Tex.), Vol. 129, No. 13, Ed. 1 Thursday, August 26, 2004
Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date:
August 26, 2004
Creator:
Lucas, Melinda L.
Object Type:
Newspaper
System:
The Portal to Texas History
Background and Legal Issues Related to Stem Cell Research
This report discusses issues regarding stem cell research. With certain restrictions, the President has announced that federal funds may be used to conduct research on human embryonic stem cells. Federal research is limited to "the more than 60" existing stem cell lines that were derived (1) with the informed consent of the donors; (2) from excess embryos created solely for reproductive purposes; and (3) without any financial inducements to the donors. No federal funds will be used for the derivation or use of stem cell lines derived from newly destroyed embryos; the creation of any human embryos for research purposes; or cloning of human embryos for any purposes.
Date:
October 26, 2004
Creator:
Shimabukuro, Jon O.
Object Type:
Report
System:
The UNT Digital Library
Fundamentals of Delayed Coking Joint Industry Project
Delayed coking evolved steadily over the early to mid 1900s to enable refiners to convert high boiling, residual petroleum fractions to light products such as gasoline. Pound for pound, coking is the most energy intensive of any operation in a modern refinery. Large amounts of energy are required to heat the thick, poor-quality petroleum residuum to the 900 to 950 degrees F required to crack the heavy hydrocarbon molecules into lighter, more valuable products. One common misconception of delayed coking is that the product coke is a disadvantage. Although coke is a low valued (near zero economic value) byproduct, compared to transportation fuels, there is a significant worldwide trade and demand for coke as it is an economical fuel. Coke production has increased steadily over the last ten years, with further increases forecast for the foreseeable future. Current domestic production is near 111,000 tons per day. A major driving force behind this increase is the steady decline in crude quality available to refiners. Crude slates are expected to grow heavier with higher sulfur contents while environmental restrictions are expected to significantly reduce the demand for high-sulfur residual fuel oil. Light sweet crudes will continue to be available and in even …
Date:
September 26, 2004
Creator:
Volk, Michael & Wisecarver, Keith
Object Type:
Report
System:
The UNT Digital Library
System Performance Characterization
Characterizing an adaptive optics (AO) system refers to understanding its performance and limitations. The goal of an AO system is to correct wavefront aberrations. The uncorrected aberrations, called the residual errors and referred to in what follows simply as the errors, degrade the image quality in the science camera. Understanding the source of these errors is a great aid in designing an AO system and optimizing its performance. This chapter explains how to estimate the wavefront error terms and the relationship between the wavefront error and the degradation of the image. The analysis deals with the particular case of a HartmannShack wavefront sensor (WFS) and a continuous deformable mirror (DM), although the principles involved can be applied to any AO system.
Date:
May 26, 2004
Creator:
van Dam, M. A.
Object Type:
Book
System:
The UNT Digital Library
High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer
Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.
Date:
May 26, 2004
Creator:
Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T. & Shi, Frank G.
Object Type:
Article
System:
The UNT Digital Library
Measurement of Cu-Doped Be Gradient Steps in Sputtered Be Capsules
The purpose of this memo is to lay the groundwork for non-destructively determining the position and ultimately the concentration of Cu gradient steps in sputtered Be capsules (or Ge steps in CH capsules) by ''simple'' radiography. A second personal objective was for me to learn something about radiography, and for that reason this memo may be more detailed than necessary. Steve Haan has suggested a design for Be capsules that makes use of a gradient of Cu-doping in a sputtered Be shell. The capsule for a 300 eV design is shown in Figure 1. The question that this memo wants to address is whether the copper concentration boundaries (and ultimately the concentration itself) can be seen and measured with our radiography system. I will focus only on the relative opacities, and not get into the practicalities of film reading, lateral resolution and the like. I will assume a monochromatic 8 keV source; clearly there are other sources and filters that can be used, as well as the fact that the source is not monochromatic. So given all these approximations lets proceed.
Date:
March 26, 2004
Creator:
Cook, B
Object Type:
Report
System:
The UNT Digital Library
Spin Tracking Studies for Beam Polarization Preservation in theNLC Main Damping Rings
We report results from studies of spin dynamics in the NLC Main Damping. Our studies have been based on spin tracking particles through the lattice under a range of conditions. We find that there are a number of spin resonances close to the nominal operating energy of 1.98 GeV; however, the effects of the resonances are weak, and the widths are narrow. We do not expect that any significant depolarization of the beam will occur during the store time.
Date:
July 26, 2004
Creator:
Wolski, Andrzej & Bates, Daniel
Object Type:
Report
System:
The UNT Digital Library
Beneficial Reuse of San Ardo Produced Water
None
Date:
September 26, 2004
Creator:
Liske, Robert A.
Object Type:
Report
System:
The UNT Digital Library
The Mechanical and Thermal Design for the MICE Detector Solenoid Magnet System
The detector solenoid for MICE surrounds a scintillating fiber tracker that is used to analyze the muon beam within the detector. There are two detector magnets for measuring the beam emittance entering and leaving the cooling channel that forms the central part of the experiment. The field in the region of the fiber detectors must be from 2.8 to 4 T and uniform to better than 1 percent over a volume that is 300 mm in diameter by 1000 mm long. The portion of the detector magnet that is around the uniform field section of the magnet consists of two short end coils and a long center coil. In addition, in the direction of the MICE cooling channel, there are two additional coils that are used to match the muon beam in the cooling channel to the beam required for the detectors. Each detector magnet module, with its five coils, will have a design stored-energy of about 4 MJ. Each detector magnet is designed to be cooled using three 1.5 W coolers. This report presents the mechanical and electrical parameters for the detector magnet system.
Date:
September 26, 2004
Creator:
Fabbricatore, P.; Farinon, S.; Perrella, M.; Bravar, U. & Green, M. A.
Object Type:
Article
System:
The UNT Digital Library
Technical Progress Report
An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. The corona generator can also be used as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. Higher peak pressures and faster pressure rise times were realized consistently in all test chambers versus standard spark plug ignition. A test engine was purchased for the project that has two spark plug ports per cylinder to The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions including cylinder pressure monitoring. A ceramic corona electrode has been designed that fits in the new test engine and is capable of withstanding the pressures and temperatures encountered inside the combustion chamber. …
Date:
August 26, 2004
Creator:
Ronney, Paul D.
Object Type:
Report
System:
The UNT Digital Library
High Pressure Materials Research: Novel Extended Phases of Molecular Triatomics
Application of high pressure significantly alters the interatomic distance and thus the nature of intermolecular interaction, chemical bonding, molecular configuration, crystal structure, and stability of solid [1]. With modern advances in high-pressure technologies [2], it is feasible to achieve a large (often up to a several-fold) compression of lattice, at which condition material can be easily forced into a new physical and chemical configuration [3]. The high-pressure thus offers enhanced opportunities to discover new phases, both stable and metastable ones, and to tune exotic properties in a wide-range of atomistic length scale, substantially greater than (often being several orders of) those achieved by other thermal (varying temperatures) and chemical (varying composition or making alloys) means. Simple molecular solids like H{sub 2}, C, CO{sub 2}, N{sub 2}, O{sub 2}, H{sub 2}O, CO, NH{sub 3}, and CH{sub 4} are bounded by strong covalent intramolecular bonds, yet relatively weak intermolecular bonds of van der Waals and/or hydrogen bonds. The weak intermolecular bonds make these solids highly compressible (i.e., low bulk moduli typically less than 10 GPa), while the strong covalent bonds make them chemically inert at least initially at low pressures. Carbon-carbon single bonds, carbon-oxygen double bonds and nitrogen-nitrogen triple bonds, for example, …
Date:
May 26, 2004
Creator:
Yoo, C.
Object Type:
Book
System:
The UNT Digital Library
Dual Beam FIB for Imaging, Nano-Sectioning and Sample Preparation of Spores: Initial Results.
Results from the first use of Focused Ion Beam (FIB) technology to section Bacillus spores at LLNL in a dual-beam (electron and ion) instrument is presented and discussed. With the use of a dual-beam instrument, high resolution imaging of single spores using low voltage scanning electron microscopy followed by FIB sectioning, SEM imaging of internal structure of the same spore is demonstrated to be possible. Additionally, FIB is shown to be able to precisely micro-machine spores thus potentially facilitating micro-scale experiments on single spores.
Date:
April 26, 2004
Creator:
Wall, M A; Fluss, M J & Schaldach, C
Object Type:
Report
System:
The UNT Digital Library
The EPA Office of Environmental Justice Small Grants Program
This report is an inventory of the profiles of the Environmental Justice Small Grants awarded for FY 2003. It shows each regions grants awards depending on socioeconomic balance, diversity of recipients, and sustainability of benefits.
Date:
October 26, 2004
Creator:
United States. Environmental Protection Agency.
Object Type:
Report
System:
The UNT Digital Library
[News Clip: Abandoning Malls]
Video footage from the KXAS-TV/NBC station in Fort Worth, Texas, to accompany a news story.
Date:
March 26, 2004
Creator:
NBC 5 (Television station : Fort Worth, Tex.)
Object Type:
Video
System:
The UNT Digital Library
The Ranger (San Antonio, Tex.), Vol. 78, No. 20, Ed. 1 Friday, March 26, 2004
Weekly student newspaper from San Antonio College in San Antonio, Texas that includes campus news along with advertising.
Date:
March 26, 2004
Creator:
San Antonio College
Object Type:
Newspaper
System:
The Portal to Texas History
Timpson & Tenaha News (Timpson, Tex.), Vol. 19, No. 8, Ed. 1 Thursday, February 26, 2004
Weekly newspaper from Timpson, Texas that includes local, state, and national news along with advertising.
Date:
February 26, 2004
Creator:
Alexander, Nancy
Object Type:
Newspaper
System:
The Portal to Texas History
Polk County Enterprise (Livingston, Tex.), Vol. 122, No. 104, Ed. 1 Sunday, December 26, 2004
Semi-weekly newspaper from Livingston, Texas that includes local, state and national news along with advertising.
Date:
December 26, 2004
Creator:
White, Barbara
Object Type:
Newspaper
System:
The Portal to Texas History