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Angular Conditions, Relations between Breit and Light-Front Frames, and Subleading Power Corrections
We analyze the current matrix elements in the general collinear (Breit) frames and find the relation between the ordinary (or canonical) helicity amplitudes and the light-front helicity amplitudes. Using the conservation of angular momentum, we derive a general angular condition which should be satisfied by the light-front helicity amplitudes for any spin system. In addition, we obtain the light-front parity and time-reversal relations for the light-front helicity amplitudes. Applying these relations to the spin-1 form factor analysis, we note that the general angular condition relating the five helicity amplitudes is reduced to the usual angular condition relating the four helicity amplitudes due to the light-front time-reversal condition. We make some comments on the consequences of the angular condition for the analysis of the high-Q{sup 2} deuteron electromagnetic form factors, and we further apply the general angular condition to the electromagnetic transition between spin-1 /2 and spin-3/2 systems and find a relation useful for the analysis of the N-Delta transition form factors. We also discuss the scaling law and the subleading power corrections in the Breit and light-front frames.
Date:
January 1, 2003
Creator:
Carlson, Carl E. & Ji, Chueng-Ryong
Object Type:
Article
System:
The UNT Digital Library
Annual Report 2002. Chemical Structure & Dynamics
This report describes the research and accomplishments of the Chemical Structure and Dynamics (CS&D) Group of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) from October 2000 through December 2001. Publications, presentations, and collaborations are listed from October 2000 to September 2002. The EMSL is a national user facility located at the Pacific Northwest National Laboratory, Richland, Washington. The CS&D program supports the Department of Energy?s mission of fostering fundamental research in the natural sciences to provide a basis for new and improved energy technologies and for understanding and mitigating the environmental impacts of energy use and contaminant releases.
Date:
January 1, 2003
Creator:
Colson, Steven D. & Gephart, Roy E.
Object Type:
Report
System:
The UNT Digital Library
Annual Report - FY 2002, Radioactive Waste Shipments To and From the Nevada Test Site
In February 1997, the U.S. Department of Energy, Nevada Operations Office issued the Mitigation Action Plan which addressed potential impacts described in the ''Final Environmental Impact Statement for the Nevada Test Site and Off-Site Locations in the State of Nevada'' (DOE/EIS 0243). The U.S. Department of Energy, Nevada Operations Office committed to several actions, including the preparation of an annual report, which summarizes waste shipments to and from the Nevada Test Site (NTS) Radioactive Waste Management Sites (RWMSs) at Area 3 and Area 5. This document satisfies requirements with regard to low-level radioactive waste (LLW) and mixed low-level radioactive waste (MLLW) transported to or from the NTS during fiscal year (FY) 2002.
Date:
January 1, 2003
Creator:
United States. National Nuclear Security Administration. Nevada Site Office.
Object Type:
Report
System:
The UNT Digital Library
Antiferromagnetic order in uranium nickel(0.39) rhodium (0.61) aluminum.
As the archetype magnetic intermetallic compounds IJNiAI (antiferromagnet, TN = 19K) and URhAI (ferromagnet, TC = 27K) [1] ., iJNi0.39Rh0.61A1 crystallizes in the hexagonal ZrNiAI-type structure . UNi0 .39Rh0.61A1 undergoes antiferromagnetic (AF) at TN = 13K . Here, we report on resistance and magnetoresistance studies on single-crystalline UNi0 .39Rh0.61A1 in magnetic field up to 18T applied along and perpendicular to the c-axis. 20-Tesla National High Magnetic Field Laboratory (NHMFL) at Los Alamos has been used to investigate such magnetic properties . This compound is found to exhibit highly anisotropic properties with the easy magnetization axis along the c-axis . While for fields applied along c-axis, 3T completely suppresses the AF ordering, antiferromagnetism persists up to the highest field of 18T applied perpendicular to the c-axis, see Fig.(1) which shows R(ohm) vs B (T) . The results are discussed in terms of variation of the 5f-ligand hybridization compared to the one of its parent compounds.
Date:
January 1, 2003
Creator:
El-Khatib, Sami; Alsmadi, A.; Nakotte, Heinz; Andreev, A. V. & Lacerda, Alex H.
Object Type:
Article
System:
The UNT Digital Library
The Application of GPR in Florida for Detecting Forensic Burials
A study was performed at the University of Florida to measure ground penetrating radar(GPR) performance for detecting forensic burials. In controlled scenarios, 24 burials were constructed with pig cadavers. Two soils were utilized to represent two of the most common soil orders in Florida: an Entisol and an Ultisol. Graves were monitored on a monthly basis for time periods up to 21 months with grid data acquired with pulsed and swept-frequency GPR systems incorporating several different frequency antennas. A small subset of the graves was excavated to assess decomposition and relate to the GPR images during the test. The grave anomalies in the GPR depth profiles became less distinctive over time due to body decomposition and settling of the disturbed soil (backfill) as it compacted. Soil type was a major factor. Grave anomalies became more difficult to recognize over time for deep targets that were within clay. Forensic targets that were in sandy soil were recognized for the duration of this study. Time elapsed imagery will be presented to elucidate the changes, or lack thereof, of grave anomalies over the duration of this study. Further analysis was performed using Synthetic Aperture Radar (SAR) reconstruction of images in 2-D and 3-D.
Date:
January 1, 2003
Creator:
Koppenjan, S. K.; Schultz, J. J.; Ono, S. & Lee, H.
Object Type:
Article
System:
The UNT Digital Library
ASME code ductile failure criteria for impulsively loaded pressure vessels
Ductile failure criteria suitable for application to impulsively loaded high pressure vessels that are designed to the rules of the ASME Code Section VI11 Division 3 are described and justified. The criteria are based upon prevention of load instability and the associated global failure mechanisms, and on protection against progressive distortion for multiple-use vessels. The criteria are demonstrated by the design and analysis of vessels that contain high explosive charges.
Date:
January 1, 2003
Creator:
Nickell, Robert E.; Duffey, T. A. (Thomas A.) & Rodriguez, E. A. (Edward A.)
Object Type:
Article
System:
The UNT Digital Library
Atomistic models of point defects in plutonium metal.
The aging properties of plutonium (Pu) metal and alloys are. driven by a combination of materials composit ion, p rocessing history, and self-irradiat ion effects . Understanding these driving forces requires a knowledge of both t h ermodynamic and defect properties of the material . The multiplicity of phases and the small changes in tempe rat u re, pressure, and/or stress that can induce phase changes lie at the heart of these properties . In terms of radiation damage, Pu metal represents a unique situation because of the large volume chan ges that accompany the phase changes . The most workable form of the meta l is the fcc (S-) phase, which in practice is stabi l ized by addit io n of a ll oying el eme n ts s u c h as Ga or Al. The thermodynamically stable phase at ambient conditions is the monoclinic (a-) phase, which, however, is 2 0 % lower i n volume th an the S phase . In stabilized Pu metal, there is an in t er play between th e n atu ral swe l li n g tendencies of fcc metals and the volume-contraction tendency of the u n …
Date:
January 1, 2003
Creator:
Valone, S. M. (Steven M.); Baskes, M. I. (Michael I.); Uberuaga, B. P. (Blas Pedro) & Voter, A. F.
Object Type:
Article
System:
The UNT Digital Library
Automated Image Registration (AIR) of MTI Imagery
This paper describes an algorithm for the registration of imagery collected by the Multispectral Thermal Imager (MTI). The Automated Image Registration (AIR) algorithm is entirely image-based and is implemented in an automated fashion, which avoids any requirement for human interaction. The AIR method differs from the 'direct georeferencing' method used to create our standard coregistered product since explicit information about the satellite's trajectory and the sensor geometry are not required. The AIR method makes use of a maximum cross-correlation (MCC) algorithm, which is applied locally about numerous points within any two images being compared. The MCC method is used to determine the row and column translations required to register the bands of imagery collected by a single SCA (band-to-band registration), and the raw and column translations required to regisler the imagery collected by the three SCAs for any individual band (SCA-to-SCA registration). Of particular note is the use of reciprocity and a weighted least squares approach to obtaining the band-to-band registration shifts. Reciprocity is enforced by using the MCC method to determine the row and column translations between all pair-wise combinations of bands. This information is then used in a weighted least squares approach to determine the optimum shift values …
Date:
January 1, 2003
Creator:
Pope, P. A. (Paul A.) & Theiler, J. P. (James P.)
Object Type:
Article
System:
The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 81, No. 35, Ed. 1 Wednesday, January 1, 2003
Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date:
January 1, 2003
Creator:
Cash, Wanda Garner
Object Type:
Newspaper
System:
The Portal to Texas History
BCS MPI: a new approach in the software design for large-scale parallel computers
BCS MPI proposes a new approach to design the communication libraries for large scale parallel machines. The emphasis of BCS MPI is on the global coordination of the potentially large number of processes and in the reduction of the non determinism rather than in the traditional optimization of the local performance of a pair of communicating processes. BCS MPI delays the interprocessor communication in order to schedule globally the communication pattern and it is designed on top of a minimal set of collective communication primitives. In this paper we describe a prototype implementation of BCS MPI and its communication protocols. The experimental results, executed on a set of scientific applications representative of the ASCI workload, show that BCS MPI is only marginally slower than the production-level MPI, but much simpler to implement, debug and analyze.
Date:
January 1, 2003
Creator:
Peinador, J. F. (Juan Fernandez) & Petrini, F. (Fabrizio)
Object Type:
Article
System:
The UNT Digital Library
BCS MPI: N new approach i the system software design for large-scale parallel computers
Buffered Co-Scheduled (BCS) MPI proposes a new approach to design the communication libraries for large-scale parallel machines. The emphasis of BCS MPI is on the global coordination of a large number of processes rather than in the traditional optimization of the local performance of a pair of communicating processes. BCS MPI delays the interprocessor communication in order to schedule globally the communication pattern and it is designed on top of a minimal set of collective communication primitives. In this paper we describe a prototype implementation of BCS MDI and its Communication protocols. The experimental results, executed on a set of scientific applications representative of the ASCI workload, show that BCS MPI is only marginally slower than the production-level MPI, but much simpler to implement, debug and analyze.
Date:
January 1, 2003
Creator:
Fernández, J. C. (Juan C.); Petrini, F. (Fabrizio) & Frachtenberg, E. (Eitan)
Object Type:
Article
System:
The UNT Digital Library
Biennial Report to the 78th Texas Legislature: State Office of Risk Managment
Biennial report to the Texas Legislature describing the activities of the State Office of Risk Management (SORM) during fiscal years 2001 and 2002, including information on state agency financing, claims, losses, and expenditures.
Date:
January 1, 2003
Creator:
Texas. State Office of Risk Management.
Object Type:
Report
System:
The Portal to Texas History
THE BIOCATALYTIC DESULFURIZATION PROJECT
During the first quarter of the Biological Desulfurization project several activities were pursued. A project kickoff meeting was held at the Diversa facility in San Diego, CA. Activities that were in process before the meeting and begun afterwards by Diversa Corporation and Petro Star Inc. include: Technology transfer in the form of information generated by Enchira to Diversa, the purchase and installation of equipment by Diversa, development of synthetic methods and preparation of organo-sulfur substrates for use in determining enzyme activities, production of extract via Petro Star's CED process, detailed analysis of Petro Star Inc. diesel and CED extract, and several activities in molecular biology. Diversa Corporation, in the area of molecular biology, engaged in several activities in support of the task list of the contract. These included: construction of a genomic library; development and utilization of a sequence-based gene discovery effort; a parallel discovery approach based on functional expression of enzymes with the ability to oxidize organosulfur compounds. Biodesulfurization genes have already been identified and are being sequenced and subcloned for expression in heterologous biological hosts. Diversa has evaluated and adapted assays developed by Enchira used to assess the activities of DBT and DBTO{sub 2} monooxygenases. Finally, Diversa personnel …
Date:
January 1, 2003
Creator:
Bonde, Steven E. & Nunn, David
Object Type:
Report
System:
The UNT Digital Library
Biopower Technical Assessment: State of the Industry and the Technology
This report provides an assessment of the state of the biopower industry and the technology for producing electricity and heat from biomass. Biopower (biomass-to-electricity generation), a proven electricity generating option in the United States and with about 11 GW of installed capacity, is the single largest source of non-hydro renewable electricity. This 11 GW of capacity encompasses about 7.5 GW of forest product industry and agricultural industry residues, about 3.0 GW of municipal solid waste-based generating capacity and 0.5 GW of other capacity such as landfill gas based production. The electricity production from biomass is being used and is expected to continue to be used as base load power in the existing electrical distribution system. An overview of sector barriers to biopower technology development is examined in Chapter 2. The discussion begins with an analysis of technology barriers that must be overcome to achieve successful technology pathways leading to the commercialization of biomass conversion and feedstock technologies. Next, an examination of institutional barriers is presented which encompasses the underlying policies, regulations, market development, and education needed to ensure the success of biopower. Chapter 3 summarizes biomass feedstock resources, characteristics, availability, delivered prices, requirements for processing, and the impediments and barriers …
Date:
January 1, 2003
Creator:
Bain, R. L.; Amos, W. P.; Downing, M. & Perlack, R. L.
Object Type:
Report
System:
The UNT Digital Library
BNL ENVIRONMENTAL MONITORING PLAN TRIENNIAL UPDATE, JANUARY 2003.
Brookhaven National Laboratory (BNL) is a multi-program national laboratory operated by Brookhaven Science Associates for the U.S. Department of Energy (DOE) and is located on a 5,265-acre site in Suffolk County, Long Island, New York. BNL has a comprehensive Environmental Management System (EMS) in place, which meets the requirements of the International Organization for Standardization 14001 EMS Standard, as described in the BNL EMS Manual. BNL's extensive environmental monitoring program is one component of the EMS, and the BNL Environmental Monitoring Plan (EMP) describes this program in detail. The data derived from systematically monitoring the various environmental media on site enable BNL to make informed decisions concerning the protection of human health and the environment and to be responsive to community concerns.
Date:
January 1, 2003
Creator:
LABORATORY, BROOKHAVEN NATIONAL
Object Type:
Report
System:
The UNT Digital Library
Bridging properties of multiblock copolymers.
Using self-consistent field theory, we attempt to elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of multiblock copolymer materials. We determine morphological aspects such as period and interfacial width and calculate the bridging fractions, and compare with experimental data .
Date:
January 1, 2003
Creator:
Rasmussen, K. O. (Kim O.); Kober, E. M. (Edward M.); Lookman, T. (Turab) & Saxena, A. B. (Avadh B.)
Object Type:
Article
System:
The UNT Digital Library
Brighter Than a Hundred Suns: Solar Power for the Southwest; Period of Performance: November 20, 2001 to October 31, 2002
Although renewable energy development will be hindered by a persistent electric generating capacity surplus and lower power prices in the Southwest through the end of the decade, we believe that the attributes of renewable energy such as power at a guaranteed price and zero air emissions will continue to stimulate investment in new projects. With the assistance of policy initiatives that contain cost- and risk-reduction measures for investments in Concentrating Solar Power, the technology has the potential to reach cost competitiveness by the end of the decade. However, in the absence of such policy initiatives, new utility-scale solar power projects in the Southwest--or elsewhere in the country--are unlikely.
Date:
January 1, 2003
Creator:
Leitner, A. & Owens, B.
Object Type:
Report
System:
The UNT Digital Library
Calculations of the structure and properties of rapidly quenched NI/ZR alloys.
Using molecular dynamics and a modified embedded atom potential developed by our group we studied the diffusivity and viscosity of molten Nil-XZrX alloys as a function of composition, temperature, and cooling rate. Previous results indicate that these potentials represent the Ni-Zr system quite well . Liquid alloys were quenched at rates of 5 x 10{sup 11} and 10{sup 12} K/s. For x < 0.04 the solidified alloys were crystalline . For higher x values, the solidified alloys were amorphous . For the amorphous alloys, the composition dependence of the calculated glass transition temperature Tg follows the general trend of experimental Tg values . The calculated viscosity and diffusivity show systematic variation with composition . For the undercooled Ni-6 at .% Zr melt the calculated viscosity shows the Vogel-Fulcher-Tamman (VFT) behavior characteristic of a 'fragile' glass .
Date:
January 1, 2003
Creator:
Cherne, F. J. (Frank J.); Baskes, M. I. (Michael I.); Schwarz, R. B. (Ricardo B.) & Srivilliputhur, S. G. (Srinivasan G.)
Object Type:
Article
System:
The UNT Digital Library
Calibrating the MKAR array using transfer functions
Developing regional discriminants (RDs) at any given seismic station requires a ground-truth database of waveforms from both earthquakes and explosions. Recently installed stations used for seismic monitoring have no single charge explosions on which to base discriminants. We have developed a procedure to map information from surrogate stations, having a long recording history, to newly installed operational stations. We investigated a method to compute transfer functions using known effective 13Ds for a database of earthquakes and explosions located near the Lop Nor nuclear test site and recorded at the KNET array in Kyrgyzstan. For specific source-station paths, transfer functions work well. However, preliminary analysis of India and Pakistan nuclear tests indicate strong azimuthal dependence in the construction of reliable transfer functions. The success of the preliminary work suggests we can apply the same technique to calibrate the recently installed MKAR array using the Global Seismic Network station MAKZ as a surrogate. Both MKAR, an 11-element array operational since 2000, and MAKZ (including its earlier counterpart MAK), operating very broadband instruments since 1994, are located in Eastern Kazakhstan and separated by 25 km. To perform the calibration requires additional considerations not taken into account during the initial investigation: (1) utilizing amplitude …
Date:
January 1, 2003
Creator:
Renwald, M. D. (Marie D.); Taylor, S. R. (Steven R.) & Wallace, Terry C.
Object Type:
Article
System:
The UNT Digital Library
Can hydrous minerals account for the observed mid-latitude water on Mars?
Great interest was generated with the discovery by the Odyssey spacecraft OC heterogeneously distributed hydrogcn at martian mid-latitudes, suggesting that large areas of the near-equatorial highlands contain near-surface deposits of 'chemically and/or physically bound 1120 and/or OH' in amounts up to 3.8% equivalent H20. More recent interpretations of the Odyssey data using new calibrations suggest that some near-equatorial areas, such as Arabia Terra, contain up to 8.5f I .3% water-equivalent hydrogen. Such shallow occurrences (<I tn) of H20 ice near the martian equator are particularly enigmatic because H20 ice is not stable at these latitudes. A number of potentially hydrous silicate phases, notably clay minerals and zeolites, have been proposed as possible M20-bearing constituents on Mars, and both groups of minerals are common terrestrial alteration products of hydrovolcanic basaltic ashes and palagonitic material comparable io those that may be widespread on Mars. Smectites within martian meteorites, attributed to hydrous alteration on Mars rather than on Earth, provide direct evidence of clay minerals from Mars. In addition, new thermal emission spectrometer (TES) data provide evidence for unspecified zeolites in martian surface dust, and concluded that spectral deconvolution of MGS TES and Mariner 9 IRIS data is consistent with the presence of …
Date:
January 1, 2003
Creator:
Bish, D. L. (David L.); Vaniman, D. T. (David T.); Fialips, C. I. (Clair I.); Carey, J. W. (James W.) & Feldman, W. C. (William C.)
Object Type:
Article
System:
The UNT Digital Library
Capture of CO2 From Recirculating Flue Gas Boilers
The possible need for an economical method for the separation of CO2 from flue gas adds a new set of challenges to power plant design, construction, operation, and maintenance. Many of the new requirements of CO2 separation are similar in nature to those addressed by the mature chemical engineering processes used in petroleum refining and industrial chemical production. Chemical engineering processes are regularly used to separate heterogeneous vapors in processes such as the fractionation of hydrocarbons or the separation of the components of air. This paper addresses the application of chemical engineering processes to the mixtures of gases and vapors found in the flue gas of recirculating boilers. Adaptation of these techniques can lead to a reduction in the energy required to capture CO2.
Date:
January 1, 2003
Creator:
Ochs, Thomas L.
Object Type:
Article
System:
The UNT Digital Library
Carbon Dioxide Capture From Flue Gas Using Dry Regenerable Sorbents Quarterly Technical Progress Report: October-December 2002
The objective of this project is to develop a simple and inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates or intermediate salts through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests suggested that high calcination temperatures decrease the activity of sodium bicarbonate Grade 1 (SBC No.1) during subsequent carbonation cycles, but there is little or no progressive decrease in activity in successive cycles. SBC No.1 appears to be more active than SBC No.3. As expected, the presence of SO{sub 2} in simulated flue gas results in a progressive loss of sorbent capacity with increasing cycles. This is most likely due to an irreversible reaction to produce Na{sub 2}SO{sub 3}. This compound appears to be stable at calcination temperatures as high as 200 C. Tests of 40% supported potassium carbonate sorbent and plain support material suggest that some of the activity observed in …
Date:
January 1, 2003
Creator:
Green, David A.; Turk, Brian S.; Portzer, Jeffrey W.; Gupta, Raghubir P.; McMichael, William J.; Liang, Ya et al.
Object Type:
Report
System:
The UNT Digital Library
Carbon dioxide sequestration by aqueous mineral carbonation of magnesium silicate minerals
The dramatic increase in atmospheric carbon dioxide since the Industrial Revolution has caused concerns about global warming. Fossil-fuel-fired power plants contribute approximately one third of the total human-caused emissions of carbon dioxide. Increased efficiency of these power plants will have a large impact on carbon dioxide emissions, but additional measures will be needed to slow or stop the projected increase in the concentration of atmospheric carbon dioxide. By accelerating the naturally occurring carbonation of magnesium silicate minerals it is possible to sequester carbon dioxide in the geologically stable mineral magnesite (MgCO3). The carbonation of two classes of magnesium silicate minerals, olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4), was investigated in an aqueous process. The slow natural geologic process that converts both of these minerals to magnesite can be accelerated by increasing the surface area, increasing the activity of carbon dioxide in the solution, introducing imperfections into the crystal lattice by high-energy attrition grinding, and in the case of serpentine, by thermally activating the mineral by removing the chemically bound water. The effect of temperature is complex because it affects both the solubility of carbon dioxide and the rate of mineral dissolution in opposing fashions. Thus an optimum temperature for carbonation of olivine …
Date:
January 1, 2003
Creator:
Gerdemann, Stephen J.; Dahlin, David C.; O'Connor, William K. & Penner, Larry R.
Object Type:
Article
System:
The UNT Digital Library
The case of the missing supercomputer performance : achieving optimal performance on the 8, 192 processors of ASCI Q
In this paper we describe how we improved the effective performance of ASCI Q, the world's second-fastest supercomputer, to meet our expectations. Using an arsenal of performance-analysis techniques including analytical models, custom microbenchmarks, full applications, and simulators, we succeeded in observing a serious-but previously undetectable-performance problem. We identified the source of the problem, eliminated the problem, and 'closed the loop' by demonstrating improved application performance. We present our methodology and provide insight into performance analysis that is immediately applicable to other large-scale cluster-based supercomputers.
Date:
January 1, 2003
Creator:
Petrini, F. (Fabrizio); Kerbyson, D. J. (Darren J.) & Pakin, S. D. (Scott D.)
Object Type:
Article
System:
The UNT Digital Library