Collection
Office of Scientific & Technical Information Technical Reports
4,638
Congressional Research Service Reports
1,530
Government Accountability Office Reports
564
Defense Base Closure and Realignment Commission
342
Texas State Publications
203
Texas Attorney General Opinions
88
End of Term Publications
57
Texas State Auditor's Office: Reports
45
Texas Register
43
Federal Communications Commission Record
20
9 More
Country
States
Decade
Month
Language
7,548 Matching Results
Results open in a new window/tab.
On macromolecular refinement at subatomic resolution withinteratomic scatterers
A study of the accurate electron density distribution in molecular crystals at subatomic resolution, better than {approx} 1.0 {angstrom}, requires more detailed models than those based on independent spherical atoms. A tool conventionally used in small-molecule crystallography is the multipolar model. Even at upper resolution limits of 0.8-1.0 {angstrom}, the number of experimental data is insufficient for the full multipolar model refinement. As an alternative, a simpler model composed of conventional independent spherical atoms augmented by additional scatterers to model bonding effects has been proposed. Refinement of these mixed models for several benchmark datasets gave results comparable in quality with results of multipolar refinement and superior of those for conventional models. Applications to several datasets of both small- and macro-molecules are shown. These refinements were performed using the general-purpose macromolecular refinement module phenix.refine of the PHENIX package.
Date:
November 9, 2007
Creator:
Afonine, Pavel V.; Grosse-Kunstleve, Ralf W.; Adams, Paul D.; Lunin, Vladimir Y. & Urzhumtsev, Alexandre
Object Type:
Article
System:
The UNT Digital Library
Geometric transitions and D-term SUSY breaking
We propose a new way of using geometric transitions to study metastable vacua in string theory and certain confining gauge theories. The gauge theories in question are N=2 supersymmetric theories deformed to N=1 by superpotential terms. We first geometrically engineer supersymmetry-breaking vacua by wrapping D5 branes on rigid 2-cycles in noncompact Calabi-Yau geometries, such that the central charges of the branes are misaligned. In a limit of slightly misaligned charges, this has a gauge theory description, where supersymmetry is broken by Fayet-Iliopoulos D-terms. Geometric transitions relate these configurations to dual Calabi-Yaus with fluxes, where H_RR, H_NS and dJ are all nonvanishing. We argue that the dual geometry can be effectively used to study the resulting non-supersymmetric, confining vacua
Date:
November 5, 2007
Creator:
Aganagic, Mina; Aganagic, Mina & Beem, Christopher
Object Type:
Article
System:
The UNT Digital Library
Co-Ordinated Coscheduling in Clusters through a Generic Framework
Communication-driven scheduling is known to be an effective technique to improve the performance of parallel workloads in time-sharing clusters. Although several such coscheduling algorithms have been proposed, to our knowledge, none of these techniques have been adopted in commercial systems. We believe this is primarily because many of these algorithms has not been exhaustively tested on real systems in presence of mixed workloads, and hence, have not been demonstrated as a favorable alternative to the traditional, batch scheduling. Moreover, practical issues like lack of a methodological approach to efficiently implement, port or reuse the necessary software have dissuaded designers from including coscheduling as a feature in the mainstream system software layer. In this paper, we attempt to fill these crucial voids by addressing several key issues. First, we propose a generic framework for deploying coscheduling techniques by providing a reusable and dynamically loadable kernel module. Second, we implement three prior dynamic coscheduling algorithms (Dynamic coscheduling (DCS), Spin Block (SB) and Periodic Boost (PB)) and a new coscheduling technique, called Co-ordinated coscheduling (CC), using the above framework. Then, we demonstrate the effectiveness of these strategies by implementing a prototype on a Myrinet connected 16-node Linux cluster that uses industry standard Virtual …
Date:
November 4, 2002
Creator:
Agarwarl, S; Choi, G S; Das, C; Yoo, A & Nagar, S
Object Type:
Article
System:
The UNT Digital Library
High-purity, isotopically enriched bulk silicon
The synthesis and characterization of dislocation-free, undoped, single crystals of Si enriched in all 3 stable isotopes is reported: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (89.8%). A silane-based process compatible with the relatively small amounts of isotopically enriched precursors that are practically available was used. The silane is decomposed to silicon on a graphite starter rod heated to 700-750 C in a recirculating flow reactor. A typical run produces 35 gm of polycrystalline Si at a growth rates of 5 {micro}m/min and conversion efficiency >95%. Single crystals are grown by the floating zone method and characterized by electrical and optical measurements. Concentrations of shallow dopants (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.
Date:
November 17, 2004
Creator:
Ager, J. W., III; Beeman, J. W.; Hansen, W. L.; Haller, E. E.; Sharp, I. D.; Liao, C. et al.
Object Type:
Article
System:
The UNT Digital Library
Industrial Assessment Center Program
The work described in this report was performed under the direction of the Industrial Assessment Center (IAC) at University of Texas at Arlington. The IAC at The University of Texas at Arlington is managed by Rutgers University under agreement with the United States Department of Energy Office of Industrial Technology, which financially supports the program. The objective of the IAC is to identify, evaluate, and recommend, through analysis of an industrial plant’s operations, opportunities to conserve energy and prevent pollution, thereby reducing the associated costs. IAC team members visit and survey the plant. Based upon observations made in the plant, preventive/corrective actions are recommended. At all times we try to offer specific and quantitative recommendations of cost savings, energy conservation, and pollution prevention to the plants we serve.
Date:
November 30, 2007
Creator:
Agonafer, Dr. Dereje
Object Type:
Report
System:
The UNT Digital Library
Pseudoscalar Semileptonic Decays of the D0 Meson
The FOCUS experiment is designed to investigate charm particle decays. These charm particles are produced by the interaction of a photon beam with an average energy of 175 GeV on a BeO target and travel an average of few millimeters before decaying in the spectrometer. By reconstructing the daughters from the decay, we can infer properties of the charm particles. Semileptonic decays have been used to measure many CKM matrix elements. These decays are interesting due to the simplicity of their theoretical description but they are experimentally challenging due to the fact that a neutrino is not detected. Analysis of semileptonic decays in the charm sector are of great interest because they provide an excellent environment to test and to calibrate theoretical calculation that can be implemented in the determination of poorly known matrix elements such as V{sub ub}. In this thesis we report an analysis of the decays D{sup 0} {yields} {pi}{sup -}{mu}{sup +}{nu} and D{sup 0} {yields} K{sup -} {mu}{sup +}{nu}. We measure the relative branching ratio as well as the ratio of the form factors f{sub +}{sup {pi}}(0)/f{sub +}{sup K}(0). Using a weighting technique, we further report a parametric analysis of the q{sup 2} dependence for both …
Date:
November 1, 2004
Creator:
Agostino, Lorenzo
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
DEVELOPMENT OF ADVANCED DRILL COMPONENTS FOR BHA USING MICROWAVE TECHNOLOGY INCORPORATING CARBIDE, DIAMOND COMPOSITES AND FUNCTIONALLY GRADED MATERIALS
The main objective of this program was to develop an efficient and economically viable microwave processing technique to process cobalt cemented tungsten carbide with improved properties for drill-bits for advanced drilling operations for oil, gas, geothermal and excavation industries. The program was completed in three years and successfully accomplished all the states goals in the original proposal. In three years of the program, we designed and built several laboratory scale microwave sintering systems for conducting experiments on Tungsten carbide (WC) based composites in controlled atmosphere. The processing conditions were optimized and various properties were measured. The design of the system was then modified to enable it to process large commercial parts of WC/Co and in large quantities. Two high power (3-6 kW) microwave systems of 2.45 GHz were built for multi samples runs in a batch process. Once the process was optimized for best results, the technology was successfully transferred to our industrial partner, Dennis Tool Co. We helped them to built couple of prototype microwave sintering systems for carbide tool manufacturing. It was found that the microwave processed WC/Co tools are not only cost effective but also exhibited much better overall performance than the standard tools. The results of …
Date:
November 1, 2000
Creator:
Agrawal, Dinesh & Roy, Rustum
Object Type:
Report
System:
The UNT Digital Library
Candidate isolated neutron stars and other optically blank x-ray fields identified from the rosat all-sky and sloan digital sky surveys
Only seven radio-quiet isolated neutron stars (INSs) emitting thermal X rays are known, a sample that has yet to definitively address such fundamental issues as the equation of state of degenerate neutron matter. We describe a selection algorithm based on a cross-correlation of the ROSAT All-Sky Survey (RASS) and the Sloan Digital Sky Survey (SDSS) that identifies X-ray error circles devoid of plausible optical counterparts to the SDSS g {approx} 22 magnitudes limit. We quantitatively characterize these error circles as optically blank; they may host INSs or other similarly exotic X-ray sources such as radio-quiet BL Lacs, obscured AGN, etc. Our search is an order of magnitude more selective than previous searches for optically blank RASS error circles, and excludes the 99.9% of error circles that contain more common X-ray-emitting subclasses. We find 11 candidates, nine of which are new. While our search is designed to find the best INS candidates and not to produce a complete list of INSs in the RASS, it is reassuring that our number of candidates is consistent with predictions from INS population models. Further X-ray observations will obtain pinpoint positions and determine whether these sources are entirely optically blank at g {approx} 22, supporting …
Date:
November 1, 2005
Creator:
Agueros, Marcel A.; Anderson, Scott F.; Margon, Bruce; Haberl, Frank; Voges, Wolfgang; Annis, James et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of \nu_\mu and \bar\nu_\mu Induced Neutral Current Single $\pi^0$ Production Cross Sections on Mineral Oil at E_\nu~O(1 GeV)
MiniBooNE reports the first absolute cross sections for neutral current single {pi}{sup 0} production on CH{sub 2} induced by neutrino and antineutrino interactions measured from the largest sets of NC {pi}{sup 0} events collected to date. The principal result consists of differential cross sections measured as functions of {pi}{sup 0} momentum and {pi}{sup 0} angle averaged over the neutrino flux at MiniBooNE. We find total cross sections of (4.76 {+-} 0.05{sub stat} {+-} 0.40{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of <E{sub {nu}}> = 808 MeV and (1.48 {+-} 0.05{sub stat} {+-} 0.14{sub sys}) x 10{sup -40} cm{sup 2}/nucleon at a mean energy of <E{sub {nu}}> = 664 MeV for {nu}{sub {mu}} and {bar {nu}}{sub {mu}} induced production, respectively. In addition, we have included measurements of the neutrino and antineutrino total cross sections for incoherent exclusive NC 1{pi}{sup 0} production corrected for the effects of final state interactions to compare to prior results.
Date:
November 1, 2009
Creator:
Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L. et al.
Object Type:
Article
System:
The UNT Digital Library
Supersymmetry Parameter Analysis: SPA Convention and Project
None
Date:
November 1, 2005
Creator:
Aguilar-Saavedra, J. A.; Ali, A.; Allanach, B. C.; Arnowitt, R.; Baer, H. A.; Bagger, J. A. et al.
Object Type:
Article
System:
The UNT Digital Library
Trade and the Americas
None
Date:
November 9, 2001
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
Trade and the Americas
None
Date:
November 19, 2002
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
Trade Liberalization Challenges Post-CAFTA
None
Date:
November 30, 2005
Creator:
Ahearn, Raymond J.
Object Type:
Report
System:
The UNT Digital Library
The German Economy and U.S.-German Economic Relations
This report first examines Germany's economic performance in historical perspective and assesses some of the domestic factors that may be contributing to Germany's suboptimal performance; the second discusses the reform challenges facing Germany's political leaders; and the third section evaluates a few salient U.S.-German economic policy differences and strains that seem to be influenced by Germany's weakened economic situation.
Date:
November 30, 2009
Creator:
Ahearn, Raymond J. & Belkin, Paul
Object Type:
Report
System:
The UNT Digital Library
Transatlantic Regulatory Cooperation: A Possible Role for Congress
This report focuses on the creation of the Transatlantic Economic Council; the role of legislatures in the regulatory process; and the Transatlantic Legislators' Dialogue and its new role as an advisor to transatlantic regulatory efforts.
Date:
November 18, 2009
Creator:
Ahearn, Raymond J. & Morelli, Vincent
Object Type:
Report
System:
The UNT Digital Library
Transatlantic Regulatory Cooperation: A Possible Role for Congress
This report focuses on the creation of the Transatlantic Economic Council; the role of legislatures in the regulatory process; and the Transatlantic Legislators' Dialogue and its new role as an advisor to transatlantic regulatory efforts.
Date:
November 7, 2008
Creator:
Ahearn, Raymond J. & Morelli, Vincent
Object Type:
Report
System:
The UNT Digital Library
U.S.-Thailand Free Trade Agreement Negotiations
Report on the trade agreements between the United States and Thailand, including commercial relations, intellectual property rights, and more.
Date:
November 3, 2005
Creator:
Ahearn, Raymond J. & Morrison, Wayne M.
Object Type:
Report
System:
The UNT Digital Library
Structure and spectroscopy of transcurium nuclei.
The stability of the superheavy elements depends on the shell corrections which are governed by the single-particle spectra. Ideally one would like to experimentally determine the single-particle levels in the superheavy nuclei but the production of only a few atoms of these nuclides precludes such measurements. One therefore has to identify single-particle levels in the heaviest nuclei which are available in at least nanoCurie amounts. They have studied the structure of such heavy nuclei in the Z=98 region and identified many single-particle states. In particular, they have studied the structure of {sup 251}Cf and {sup 249}Bk by measuring the radiations emitted in the {alpha} decay of {sup 255}Fm and {sup 253}Es. These single-particle spectra can be used to test theoretical models for superheavy elements.
Date:
November 9, 2001
Creator:
Ahmad, I.
Object Type:
Article
System:
The UNT Digital Library
Advanced Computational Model for Three-Phase Slurry Reactors Progress Report: November 2000
In the first year of the project, solid-fluid mixture flows in ducts and passages at different angle of orientations were analyzed. The model predictions are compared with the experimental data and good agreement was found. Progress was also made in analyzing the gravity chute flows of solid-liquid mixtures. An Eulerian-Lagrangian formulation for analyzing three-phase slurry flows in a bubble column is being developed. The approach uses an Eulerian analysis of gas liquid flows in the bubble column, and makes use of the Lagrangian particle tracking procedure to analyze the particle motions. Progress was also made in developing a rate dependent thermodynamically consistent model for multiphase slurry flows in a state of turbulent motion. The new model includes the effect of phasic interactions and leads to anisotropic effective phasic stress tensors. Progress was also made in measuring concentration and velocity of particles of different sizes near a wall in a duct flow. The formulation of a thermodynamically consistent model for chemically active multiphase solid-fluid flows in a turbulent state of motion was also initiated. The general objective of this project is to provide the needed fundamental understanding of three-phase slurry reactors in Fischer-Tropsch (F-T) liquid fuel synthesis. The other main goal …
Date:
November 1, 2000
Creator:
Ahmadi, Goodarz
Object Type:
Report
System:
The UNT Digital Library
EARLY ENTRANCE COPRODUCTION PLANT
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing …
Date:
November 22, 2002
Creator:
Ahmed, Mushtaq; Anderson, John H.; Berry, Earl R.; Brent, Fred; He, Ming; Ong, Jimmy O. et al.
Object Type:
Report
System:
The UNT Digital Library
GEM-type detectors using LIGA and etchable glass technologies
Gas electron multipliers (GEMS) have been made by a deep X-ray lithography technique (LIGA process) using synchrotron radiation on polymethylmethacrylate (PMMA) and by UV processes using a UV etchable glass. Gain, stability and rate capability for these detectors are described.The LIGA detectors described consist of PMMA sheets of various thicknesses, 125mm to 350mm, and have 150mm x 150mm square holes spaced with a pitch of 300mm. Thin copper electrodes are plated on the top and bottom surfaces using a Damascene method, followed by electroless plating of the copper onto a palladium-tin base layer. For various thicknesses of PMMA measurements have been made of absolute gain vs. voltage, time stability of gain, and rate capability. The operating gas mixture was usually Ar/CO2 (70/30) gas, but some tests were also done using P10 gas. We also made GEM-like detectors using the UV etchable glass called Foturan, patterned by exposure to UV light and subsequent etching. A few measurements using these detectors will be reported, including avalanche gain and time stability.
Date:
November 2, 2001
Creator:
Ahn, S. K.; Kim, J. G.; Perez-Mendez, V.; Chang, S.; Jackson, K. H.; Kadyk, J. A. et al.
Object Type:
Article
System:
The UNT Digital Library
Thoughts and ''Facts'' From the Ags Polarized Proton Runs During the 1980s.
This workshop's focus is on considering ways for improving the proton beam polarization that the AGS delivers to the RHIC. This talk attempts to review the first decade of AGS polarization--the 1980's; to briefly describe some aspects of the machine situation, the depolarization avoidance strategies employed and the success achieved in AGS from the perspective of one of those involved.
Date:
November 6, 2002
Creator:
Ahrens, L.
Object Type:
Article
System:
The UNT Digital Library
ACOUSTIC FORMING FOR ENHANCED DEWATERING AND FORMATION
The next generation of forming elements based on acoustic excitation to increase drainage and enhances formation both with on-line control and profiling capabilities has been investigated in this project. The system can be designed and optimized based on the fundamental experimental and computational analysis and investigation of acoustic waves in a fiber suspension flow and interaction with the forming wire.
Date:
November 30, 2007
Creator:
Aidun, Cyrus K
Object Type:
Report
System:
The UNT Digital Library
Measured Energy Savings from the Application of Reflective Roofs in 3 AT and T Regeneration Buildings
Energy use and environmental parameters were monitored in three AT and T regeneration buildings during the summer of 2000. These buildings are constructed with concrete and are about 14.9 m2 (160 f2; 10x16 ft)in size. The buildings were initially monitored for about 1 1/2 months to establish a base condition. Then, the roofs of the buildings were painted with a white coating and the monitoring was continued. The original roof reflectances were about 26 percent; after the application of roof coatings the reflectivities increased to about 72 percent. In two of these buildings, we monitored savings of about 0.5kWh per day (8.6 kWh/m2 [0.8 kWh/ft2]). The third building showed a reduction in air-conditioning energy use of about 13kWh per day. These savings probably resulted from the differences in the performance (EER) of the two dissimilar AC units in this building. The estimated annual savings for two of the buildings are about 125kWh per year; at a cost of dollar 0.1/kWh, savings are about dollar 12.5 per year. Obviously, it costs significantly more than this amount to coat the roofs with reflective coating, particularly because of the remote location of the buildings. However, since the prefabricated roofs are already painted green …
Date:
November 1, 2000
Creator:
Akbari, Hashen & Rainer, Leo
Object Type:
Report
System:
The UNT Digital Library