Collection
Office of Scientific & Technical Information Technical Reports
499
Congressional Research Service Reports
229
Government Accountability Office Reports
102
Texas State Publications
35
Texas Attorney General Opinions
11
End of Term Publications
5
Texas State Auditor's Office: Reports
5
Texas Register
4
Federal Communications Commission Record
2
Country
States
Year
Month
Language
892 Matching Results
Results open in a new window/tab.
Results:
1 - 24 of
892
next
F(1) for B (forward) D*ln from lattice QCD
The authors would like to determine |V{sub cb}| from the exclusive semi-leptonic decay B{yields}D*lv. The differential decay rate is d{Lambda}/dw = G{sub F}{sup 2}/4{pi}{sup 3}(w{sup 2}-1){sup 1/2}m{sub D*}{sup 3} (m{sub B}-m{sub D*}){sup 2}G(w)|V{sub cb}|{sup 2}|F{sub B{yields}D*}(w)|{sup 2}, where w = v {center_dot} v{prime} and G(1) = 1. At zero recoil (w = 1) heavy-quark symmetry requires F{sub B{yields}D*}(1) to be close to 1. So, |V{sub cb}| is determined by dividing measurements of d{Lambda}/dw by the phase space and well-known factors, and extrapolating to w {yields} 1. This yields |V{sub cb}|F{sub B{yields}D*}(1), and F{sub B{yields}D*}(1) is taken from ''theory''. To date models [1] or a combination of a rigorous inequality plus judgement [2] have been used to estimate F{sub B{yields}D*}(1) - 1. In this work [3] they calculate F{sub B{yields}D*}(1) with lattice gauge theory, in the so-called quenched approximation, but the uncertainty from quenching is included in the error budget.
Date:
July 12, 2002
Creator:
A.S. Kronfeld, P.B. Mackenzie and J.N. Simone
Object Type:
Article
System:
The UNT Digital Library
Acoustic Wave Equations for a Linear Viscous Fluid and An Ideal Fluid
The mathematical description of acoustic wave propagation within a time- and space-varying, and moving, linear viscous fluid is formulated as a system of coupled linear equations. This system is rigorously developed from fundamental principles of continuum mechanics (conservation of mass, balance of linear and angular momentum, balance of entropy) and various constitutive relations (for stress, entropy production, and entropy conduction) by linearizing all expressions with respect to the small-amplitude acoustic wavefield variables. A significant simplification arises if the fluid medium is neither viscous nor heat conducting (i.e., an ideal fluid). In this case the mathematical system can be reduced to a set of five, coupled, first-order partial differential equations. Coefficients in the systems depend on various mechanical and thermodynamic properties of the ambient medium that supports acoustic wave propagation. These material properties cannot all be arbitrarily specified, but must satisfy another system of nonlinear expressions characterizing the dynamic behavior of the background medium. Dramatic simplifications in both systems occur if the ambient medium is simultaneously adiabatic and stationary.
Date:
July 1, 2002
Creator:
ALDRIDGE, DAVID F.
Object Type:
Report
System:
The UNT Digital Library
Elastic Wave Radiation from a Pressurized Spherical Cavity
None
Date:
July 1, 2002
Creator:
ALDRIDGE, DAVID F.
Object Type:
Report
System:
The UNT Digital Library
NUFACT02 MACHINE WORKING GROUP SUMMARY.
At {nu}Fact'02, the muon-based neutrino factory was confronted with existing and planned neutrino facilities. When it was first discussed in 1999 in Lyon [1], it raised great enthusiasm, especially because it was thought to be the only machine capable of measuring CP violation in the leptonic sector. Since that time the pendulum has partially swung back. Two successive detailed studies [2, 3] have shown that a neutrino Factory and the needed R&D were both expensive. In terms of present experiments, neutrino oscillations have been confirmed at SuperK and SNO and results are soon expected from KamLAND. K2K, MniBOONE, MINOS and CNGS are going ahead and new perspectives have been opened by off-axis pion-based neutrino beams and the approval of the high intensity Japanese Hadron Facility. Crests and troughs of a wave are common in long term projects. They are even healthy because they force us to scrutinize the first ideas and sometimes to invent new ones to reach a realistic and affordable design. This analysis has been applied to target systems (section 2), RF capture and cooling of the muons (section 4) and accelerators (section 5). The new concept of pure electron neutrino or anti-neutrino beams produced by, {beta}-decay is …
Date:
July 1, 2002
Creator:
AUTIN,B. FERNOW,R. C. MACHIDA,S. HARRIS,D. A.
Object Type:
Article
System:
The UNT Digital Library
Compression effects on pressure loss in flexible HVAC ducts
A study was conducted to evaluate the effect of compression on pressure drop in flexible, spiral wire helix core ducts used in residential and light commercial applications. Ducts of 6 inches, 8 inches and 10 inches (150, 200 and 250 mm) nominal diameters were tested under different compression configurations following ASHRAE Standard 120-1999--Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings. The results showed that the available published references tend to underestimate the effects of compression. The study demonstrated that moderate compression in flexible ducts, typical of that often seen in field installations, could increase the pressure drop by a factor of four, while further compression could increase the pressure drop by factors close to ten. The results proved that the pressure drop correction factor for compressed ducts cannot be independent of the duct size, as suggested by ASHRAE Fundamentals, and therefore a new relationship was developed for better quantification of the pressure drop in flexible ducts. This study also suggests potential improvements to ASHRAE Standard 120-1999 and provides new data for duct design.
Date:
July 1, 2002
Creator:
Abushakra, Bass; Walker, Iain S. & Sherman, Max H.
Object Type:
Article
System:
The UNT Digital Library
A Study of Pressure Losses in Residential Air Distribution Systems
An experimental study was conducted to evaluate the pressure drop characteristics of residential duct system components that are either not available or not thoroughly (sometimes incorrectly) described in existing duct design literature. The tests were designed to imitate cases normally found in typical residential and light commercial installations. The study included three different sizes of flexible ducts, under different compression configurations, splitter boxes, supply boots, and a fresh air intake hood. The experimental tests conformed to ASHRAE Standard 120P--''Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings''. The flexible duct study covered compressibility and bending effects on the total pressure drop, and the results showed that the available published references tend to underestimate the effects of compression in flexible ducts that can increase pressure drops by up to a factor of nine. The supply boots were tested under different configurations including a setup where a flexible duct elbow connection was considered as an integral part of the supply boot. The supply boots results showed that diffusers can increase the pressure drop by up to a factor of two in exit fittings, and the installation configuration can increase the pressure drop by up to a factor of …
Date:
July 1, 2002
Creator:
Abushakra, Bass; Walker, Iain S. & Sherman, Max H.
Object Type:
Article
System:
The UNT Digital Library
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:
July 16, 2002
Creator:
Ackerman, David M.
Object Type:
Report
System:
The UNT Digital Library
Supreme Court: Church-State Cases, 2001-2002 Term
This issue brief discusses a number of Supreme Court cases that heavily concern church and state from the 2001-2002 Term. It provides detailed summaries on two decided cases, Watchtower Bible & Tract Society of New York, Inc v. Stratton, Ohio and Zelman v. Selmon-Harris.
Date:
July 12, 2002
Creator:
Ackerman, David M.
Object Type:
Report
System:
The UNT Digital Library
Atomic Line Shapes in the Presence of an External Magnetic Field
Both the theoretical basis and computational approach for extending the capabilities of a spectral line broadening code are presented. Following standard line broadening theory, the effects of an external magnetic field are incorporated into the atomic Hamiltonian and plasma average. In the presence of an external magnetic field the atomic Hamiltonian angular properties are altered--atomic energy levels are perturbed and the spectral emission line is polarized. The magnetic field introduces a preferential axis that changes the plasma average. These extensions have been incorporated into a new spectral line broadening code that is applied to several problems of importance to the understanding of tokamak edge plasmas. Applications fall into two broad categories: (1) determination of local plasma properties from distinct line shape features; and (2) consideration of global plasma phenomenon, such as radiation transport. Observable features of the Zeeman effect make H{sub {alpha}} a good magnetic field diagnostic. H{sub {beta}} does not make a good electron density diagnostic since the Zeeman effect is comparable to the Stark effect for a majority of tokamak edge plasma conditions. When optically thick lines exist the details of the spectral line shapes are shown to significantly influence the transport of radiation throughout the system.
Date:
July 3, 2002
Creator:
Adams, M L; Lee, R W; Scott, H A; Chung, H K & Klein, L
Object Type:
Article
System:
The UNT Digital Library
Interplay of Hard and Soft Processes at JLAB Energies
Even at moderate energy machines, there is a regime where hard pion electroproduction proceeds by a perturbatively calculable process. The process, we claim, is not the leading twist fragmentation one but a rather higher twist process that produces kinematically isolated pions. Semiexclusive data may teach us more about parton distribution functions of the target and the pion distribution amplitude. In addition, there is a connection to generalized parton distribution calculations of exclusive processes in that the perturbative kernel is the same.
Date:
July 1, 2002
Creator:
Afanasev, Andrei & Carlson, Carl E.
Object Type:
Article
System:
The UNT Digital Library
Trade and the Americas
None
Date:
July 11, 2002
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
U.S.-European Union Trade Relations: Issues and Policy Challenges
None
Date:
July 18, 2002
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
Particle Transportation and Deposition in Hot Gas Filter Vessels - a Computational and Experimental Modeling Approach
In this project, a computational modeling approach for analyzing flow and ash transport and deposition in filter vessels was developed. An Eulerian-Lagrangian formulation for studying hot-gas filtration process was established. The approach uses an Eulerian analysis of gas flows in the filter vessel, and makes use of the Lagrangian trajectory analysis for the particle transport and deposition. Particular attention was given to the Siemens-Westinghouse filter vessel at Power System Development Facility in Wilsonville in Alabama. Details of hot-gas flow in this tangential flow filter vessel are evaluated. The simulation results show that the rapidly rotation flow in the spacing between the shroud and the vessel refractory acts as cyclone that leads to the removal of a large fraction of the larger particles from the gas stream. Several alternate designs for the filter vessel are considered. These include a vessel with a short shroud, a filter vessel with no shroud and a vessel with a deflector plate. The hot-gas flow and particle transport and deposition in various vessels are evaluated. The deposition patterns in various vessels are compared. It is shown that certain filter vessel designs allow for the large particles to remain suspended in the gas stream and to deposit …
Date:
July 1, 2002
Creator:
Ahmadi, Goodarz
Object Type:
Report
System:
The UNT Digital Library
Scalable Analysis Techniques for Microprocessor Performance Counter Metrics
Contemporary microprocessors provide a rich set of integrated performance counters that allow application developers and system architects alike the opportunity to gather important information about workload behaviors. These counters can capture instruction, memory, and operating system behaviors. Current techniques for analyzing data produced from these counters use raw counts, ratios, and visualization techniques to help users make decisions about their application source code. While these techniques are appropriate for analyzing data from one process, they do not scale easily to new levels demanded by contemporary computing systems. Indeed, the amount of data generated by these experiments is on the order of tens of thousands of data points. Furthermore, if users execute multiple experiments, then we add yet another dimension to this already knotty picture. This flood of multidimensional data can swamp efforts to harvest important ideas from these valuable counters. Very simply, this paper addresses these concerns by evaluating several multivariate statistical techniques on these datasets. We find that several techniques, such as statistical clustering, can automatically extract important features from this data. These derived results can, in turn, be feed directly back to an application developer, or used as input to a more comprehensive performance analysis environment, such as …
Date:
July 24, 2002
Creator:
Ahn, D H & Vetter, J S
Object Type:
Article
System:
The UNT Digital Library
Calculation of the Mean Energy Loss in the BTA Stripping Foils and Comparison with Measurement
N/A
Date:
July 1, 2002
Creator:
Ahrens, L. & Gardner, C. J.
Object Type:
Report
System:
The UNT Digital Library
ADVANCED DIAGNOSTIC TECHNIQUES FOR THREE-PHASE SLURRY BUBBLE COLUMN REACTORS(SBCR)
This report summarizes the accomplishment made during the third year of this cooperative research effort between Washington University, Ohio State University and Air Products and Chemicals. Data processing of the performed Computer Automated Radioactive Particle Tracking (CARPT) experiments in 6 inch column using air-water-glass beads (150 {micro}m) system has been completed. Experimental investigation of time averaged three phases distribution in air-Therminol LT-glass beads (150 {micro}m) system in 6 inch column has been executed. Data processing and analysis of all the performed Computed Tomography (CT) experiments have been completed, using the newly proposed CT/Overall gas holdup methodology. The hydrodynamics of air-Norpar 15-glass beads (150 {micro}m) have been investigated in 2 inch slurry bubble column using Dynamic Gas Disengagement (DGD), Pressure Drop fluctuations, and Fiber Optic Probe. To improve the design and scale-up of bubble column reactors, a correlation for overall gas holdup has been proposed based on Artificial Neural Network and Dimensional Analysis.
Date:
July 25, 2002
Creator:
Al-Dahhan, M.H.; Fan, L.S. & Dudukovic, M.P.
Object Type:
Report
System:
The UNT Digital Library
SNAP sky background at the north ecliptic pole
I summarize the extant direct and indirect data on the sky background SNAP will see at the North Ecliptic Pole over the wavelength range 0.4 < {lambda} < 1.7 {micro}m. At the spatial resolution of SNAP the sky background due to stars and galaxies is resolved, so the only source considered is zodiacal light. Several models are explored to provide interpolation in wavelength between the broadband data from HST and COBE observations. I believe the input data are now established well enough that the accuracy of the sky background presented here is sufficient for SNAP simulations, and that it will stand up to scrutiny by reviewers.
Date:
July 1, 2002
Creator:
Aldering, Greg
Object Type:
Report
System:
The UNT Digital Library
Overview of the nearby supernova factory
The Nearby Supernova Factory (SNfactory) is an international experiment designed to lay the foundation for the next generation of cosmology experiments (such as CFHTLS, wP, SNAP and LSST) which will measure the expansion history of the Universe using Type Ia supernovae. The SNfactory will discover and obtain frequent lightcurve spectrophotometry covering 3200-10000 {angstrom} for roughly 300 Type Ia supernovae at the low-redshift end of the smooth Hubble flow. The quantity, quality, breadth of galactic environments, and homogeneous nature of the SNfactory dataset will make it the premier source of calibration for the Type Ia supernova width-brightness relation and the intrinsic supernova colors used for K-correction and correction for extinction by host-galaxy dust. This dataset will also allow an extensive investigation of additional parameters which possibly influence the quality of Type Ia supernovae as cosmological probes. The SNfactory search capabilities and follow-up instrumentation include wide-field CCD imagers on two 1.2-m telescopes (via collaboration with the Near Earth Asteroid Tracking team at JPL and the QUEST team at Yale), and a two-channel integral-field-unit optical spectrograph/imager being fabricated for the University of Hawaii 2.2-m telescope. In addition to ground-based follow-up, UV spectra for a subsample of these supernovae will be obtained with HST. …
Date:
July 29, 2002
Creator:
Aldering, Greg; Adam, Gilles; Antilogus, Pierre; Astier, Pierre; Bacon, Roland; Bongard, S. et al.
Object Type:
Article
System:
The UNT Digital Library
Modeling of liquid metal duct and free-surface flows using CFX.
Liquid metal free-surface flows provide an option of a renewable surface for heat absorption, removal of impurities, and eliminating the problems of erosion and thermal stresses [1], [2]. In a tokamak liquid metal flows through a strong magnetic field, which results in a magnetohydrodynamic (MHD) interaction. For a free-surface flow the MHD interaction may be even more important than for the duct flows in blankets, because the electromagnetic forces may significantly deform the free-surface and thus make it unfavorable for heat extraction. The MHD-related problems for the free-surface flows have been reviewed in [3]. Among the most important ones are the effects of nonuniform magnetic fields, inertia, surface tension, wettability and roughness of walls on both the jet/drop shape and trajectory. The main problems for the jet divertor are shown in Figure 1 and Figure 2 [4]. Particular issues related to some of the problems listed in these figures have already been tackled (Problem 1 in [5]-[7], 4 in [8], [9], 5 in [9], 6 in [4], 7 and 10 in [9], 9 in [10]). Once main fundamental aspects for each of these sub-problems are understood, the analysis will have been performed for a particular divertor design.
Date:
July 23, 2002
Creator:
Aleksandrova, S.; Molokov, S. & Reed, C. B.
Object Type:
Report
System:
The UNT Digital Library
Summary of Chariton Valley Switchgrass Co-Fire Testing at the Ottumwa Generating Station in Chillicothe, Iowa: Milestone Completion Report
Results of the switchgrass co-firing tests conducted at the Ottumwa Generating Station in Chillicothe, Iowa as part of the Chariton Valley Biomass Project. After several years of planning, the Chariton Valley Biomass Project successfully completed two months of switchgrass co-fire testing at the Ottumwa Generating Station (OGS) in Chillicothe, Iowa. From November 30, 2000, through January 25, 2001, the switchgrass team co-fired 1,269 tons (1,151 tonnes) of switchgrass at rates up to 16.8 tons/h (15.2 tonne/h), representing about 3% heat input to the 725-MW power plant. Stack testing was completed when co-firing switchgrass and when burning only coal. Fuel and ash samples were collected for analysis, and boiler performance and emissions data were collected. Numerous improvements were made to the feed-handling equipment during testing. The co-fire testing was completed with no environmental incidents, no injuries to personnel, and no loss in electricity output from OGS. The goals of the this--the first of three rounds of co-fire tests--were: to identify the effects of co-firing on boiler performance, to measure any changes in emissions during co-firing, and to gather information to improve the design of the switchgrass handling equipment. All three of these goals were met. The design target for the switchgrass …
Date:
July 1, 2002
Creator:
Amos, W.
Object Type:
Report
System:
The UNT Digital Library
Signaling to the P53 Tumor Suppressor Through Pathways Activated by Genotoxic and Non-Genotoxic Stresses.
The p53 tumor suppressor is a tetrameric transcription factor that is post-translational modified at {approx}18 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review the posttranslational modifications to p53 and the pathways that produce them in response to both genotoxic and non-genotoxic stresses.
Date:
July 1, 2002
Creator:
Anderson, C. W. & Appella, E.
Object Type:
Book
System:
The UNT Digital Library
Development of Metallic Filters for Hot Gas Cleanup in Pressurized Fluidized Bed Combustion Applications
None
Date:
July 1, 2002
Creator:
Anderson, Iver E.; Gleeson, Brian & Terpstra, Robert L.
Object Type:
Article
System:
The UNT Digital Library
Coming to Washington, D.C.? Sources of Information on Temporary Housing
This report will introduce a newcomer to the Washington, D.C., metropolitan area to sources of general interest, neighborhoods, housing, and public transportation. The intended audience is congressional staff needing short-term or summer housing, although many of the sources given may also be helpful for those needing more than a three- to six-month lease. Sources suggested are often accessible by their Internet addresses.
Date:
July 3, 2002
Creator:
Anderson, J. Michael
Object Type:
Report
System:
The UNT Digital Library
Enron: A Select Chronology of Congressional, Corporate, and Government Activities
This report presents basic background information on the collapse of the Enron Corporation, identifying public policy issues in financial market oversight. This report briefly summarizes some federal laws carrying criminal penalties which may be implicated in the events surrounding the collapse of the Enron Corp. This report compares the auditing and accounting reform measures passed by the House (H.R. 3763) and reported by the Senate Committee on Banking, Housing, and Urban Affairs. This report compares the major provisions of three auditor and accounting reform proposals: H.R. 3763, S. 2673, and a rule proposed on June 20, 2002, by the SEC that would create a new auditor oversight board by using the SEC’s existing authority to regulate corporate accounting. The report focuses on Section 404(a) of the Employee Retirement Income Security Act (ERISA), the federal statute that regulates employer-sponsored pension plans. Section 404(a) is considered the “touchstone for understanding the scope and object of an ERISA fiduciary’s duties.”
Date:
July 12, 2002
Creator:
Anderson, J. Michael
Object Type:
Report
System:
The UNT Digital Library