The dihadron fragmentation function and its evolution (open access)

The dihadron fragmentation function and its evolution

Dihadron fragmentation functions and their evolution arestudied in the process of e+e- annihilation. Under the collinearfactorization approximation and facilitated by the cut-vertex technique,the two hadron inclusive cross section at leading order (LO) is shown tofactorize into a short distance parton cross section and a long distancedihadron fragmentation function. We provide the definition of such adihadron fragmentation function in terms of parton matrix elements andderive its DGLAP evolution equation at leading log. The evolutionequation for the non-singlet quark fragmentation function is solvednumerically with a simple ansatz for the initial condition and resultsare presented for cases of physical interest.
Date: February 24, 2004
Creator: Majumder, Abhijit & Wang, Xin-Nian
Object Type: Article
System: The UNT Digital Library
Power Systems Development Facility Gasification Test Campaign TC16 (open access)

Power Systems Development Facility Gasification Test Campaign TC16

In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR (formerly Kellogg Brown & Root) Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report discusses Test Campaign TC16 of the PSDF gasification process. TC16 began on July 14, 2004, lasting until August 24, 2004, for a total of 835 hours of gasification operation. The test campaign consisted of operation using Powder River Basin (PRB) subbituminous coal and high sodium lignite from the North Dakota Freedom mine. The highest gasifier operating temperature mostly varied from 1,760 to 1,850 F with PRB and 1,500 to 1,600 F with lignite. Typically, during PRB operations, the gasifier exit pressure was maintained between 215 and 225 psig using air as the gasification oxidant and between 145 and 190 psig while using oxygen as the oxidant. With lignite, the gasifier operated only in air-blown mode, and the gasifier outlet pressure ranged from 150 …
Date: August 24, 2004
Creator: Southern Company Services
Object Type: Report
System: The UNT Digital Library
Measurement of Electron Impact Collisional Excitation Cross Sections of Ni to Ga-Like Gold (open access)

Measurement of Electron Impact Collisional Excitation Cross Sections of Ni to Ga-Like Gold

None
Date: August 24, 2004
Creator: May, M.; Beiersdorfer, P.; Jordan, N.; Scofield, J.; Reed, K.; Hansen, S. et al.
Object Type: Article
System: The UNT Digital Library
Experimental investigation of high mach number 3D hydrodynamic jets at the National Ignition Facility (open access)

Experimental investigation of high mach number 3D hydrodynamic jets at the National Ignition Facility

The first hydrodynamics experiments were performed on the National Ignition Facility. A supersonic jet was formed via the interaction of a laser driven shock ({approx}40 Mbars) with 2D and 3D density perturbations. The temporal evolution of the jet's spatial scales and ejected mass were measured with point projection x-ray radiography. Measurements of the large-scale features and mass are in good agreement with 2D and 3D numerical simulations. These experiments are the first quantitative measurements of the evolution of 3D supersonic jets and provide insight into their 3D behavior.
Date: September 24, 2004
Creator: Blue, B. E.; Weber, S.; Glendinning, S.; Lanier, N.; Woods, D.; Bono, M. et al.
Object Type: Article
System: The UNT Digital Library
Simulation of Plasma Fluxes to Material Surfaces with Self-Consistent Edge Turbulence and Transport for Tokamaks (open access)

Simulation of Plasma Fluxes to Material Surfaces with Self-Consistent Edge Turbulence and Transport for Tokamaks

The edge-plasma profiles and fluxes to the divertor and walls of a divertor tokamak with a magnetic X-point are simulated by coupling a 2D transport code (UEDGE) and a 3D turbulence code (BOUT). An relaxed iterative coupling scheme is used where each code is run on its characteristic time scale, resulting in a statistical steady state. Plasma variables of density, parallel velocity, and separate ion and electron temperatures are included, together with a fluid neutral model for recycling neutrals at material surfaces. Results for the DIII-D tokamak parameters show that the turbulence is preferentially excited in the outer radial region of the edge where magnetic curvature is destabilizing and that substantial plasma particle flux is transported to the main chamber walls. These results are qualitatively consistent with some experimental observations. The coupled transport/turbulence simulation technique provides a strategy to understanding edge-plasma physics in more detailed than previously available and to significantly enhance the realism of predictions of the performance of future devices.
Date: May 24, 2004
Creator: Rognlien, T.; Umansky, M.; Xu, X.; Cohen, R. & LoDestro, L.
Object Type: Article
System: The UNT Digital Library
The Effect of Scale on the Mechanical Properties of Jointed Rock Masses (open access)

The Effect of Scale on the Mechanical Properties of Jointed Rock Masses

These notes were prepared for presentation at the Defense Threat Reduction Agency's (DTRA) Hard Target Research and Analysis Center (HTRAC), at the occasion of a short course held on June 14-15, 2004. The material is intended for analysts who must evaluate the geo-mechanical characteristics of sites of interest, in order to provide appropriate input to calculations of ground shock effects on underground facilities in rock masses. These analysts are associated with the Interagency Geotechnical Assessment Team (IGAT). Because geological discontinuities introduce scale effects on the mechanical properties of rock formations, these large-scale properties cannot be estimated on the basis of tests on small cores.
Date: May 24, 2004
Creator: Heuze, Francois E.
Object Type: Report
System: The UNT Digital Library
Lessons Learned on X-ray Optics Fabrication: Work completed as part of the "Advancing the Technology R&D of Tabletop Mesoscale Nondestructive Characterization" LDRD (open access)

Lessons Learned on X-ray Optics Fabrication: Work completed as part of the "Advancing the Technology R&D of Tabletop Mesoscale Nondestructive Characterization" LDRD

A Wolter X-ray optic was the central component of the microscope envisioned to fulfill the imaging requirements of the Characterization SI. After encountering many difficulties and delays, an optic was finally produced that, unfortunately, only partially met its specifications. With the SI halted, and efforts underway to reformulate a LDRD program to support fabrication of X-ray optics, it is useful to examine the previous effort and compile a list of lessons learned during the research.
Date: November 24, 2004
Creator: Pivovaroff, M J; Nederbragt, W W & Martz, H E
Object Type: Report
System: The UNT Digital Library
Comparison of Plasma Parameters Between QH and ELMing Phases of the Same Discharges (open access)

Comparison of Plasma Parameters Between QH and ELMing Phases of the Same Discharges

H-mode confinement is observed for many energy confinement times without edge localized modes (ELMs) in QH (quiescent high-confinement)-mode discharges in DIII-D. To find critical differences between ELMing and QH modes we compared electron temperature (T{sub e}), density (n{sub e}), and ion temperature (T{sub i}), in the pedestal and scrape-off layer (SOL) for a group of discharges. We also compared the electron pressures P{sub ped}, and maximum pressure gradients P{sub e,ped,max grad} because of their importance in confinement and stability. Experimental results show that the core line averaged density, median T{sub e} (pedestal), SOL T{sub e}, and T{sub e} pedestal width, and SOL T{sub i} are nearly the same in QH mode as that during ELMs. The n{sub e} (average pedestal), n{sub e} pedestal width, P{sub ped}, and P{sub e,ped,max grad} are similar to corresponding values in QH mode and at various times between ELMs. However, the pedestal T{sub i} is 1.6 times higher in QH mode than during ELMing.
Date: May 24, 2004
Creator: Lasnier, C.; West, W.; Burrell, K.; deGrassie, J.; Doyle, E. & Osborne, T.
Object Type: Article
System: The UNT Digital Library
NAFEMS Finite Element Benchmarks for MDG Code Verification (open access)

NAFEMS Finite Element Benchmarks for MDG Code Verification

NAFEMS was originally founded at the United Kingdom's National Engineering Laboratory as the National Agency for Finite Element Methods and Standards. It was subsequently privatized as the not-for-profit organization NAFEMS, Ltd., but retains its mission ''To promote the safe and reliable use of finite element and related technology''. That mission has been pursued in part by sponsoring a series of studies that published benchmarked deemed suitable to assess the basic accuracy of engineering simulation tools. The early studies focused on FEA for linear solid and structural mechanics and then extended to nonlinear solid mechanics, eventually including contact. These benchmarks are complemented by educational materials concerning analysis technologies and approaches. More recently NAFEMS is expanding to consider thermal-fluid problems. Further information is available at www.nafems.org. Essentially all major commercial firms selling FEA for solid mechanics are members of NAFEMS and it seemed clear that Methods Development Group should leverage from this information resource, too. In 2002, W Program ASCI funding purchased a three-year membership in NAFEMS. In the summer of 2003 the first author hosted a summer graduate student to begin modeling some of the benchmark problems. We concentrated on NIKE3D, as the benchmarks are most typically problems most naturally run …
Date: February 24, 2004
Creator: Greer, R & Ferencz, R M
Object Type: Report
System: The UNT Digital Library
Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery (open access)

Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery

Lawrence Livermore National Laboratory participated in a U. S. Department of Energy/Office of Industrial Technology sponsored research project 'Development of a Rolling Process Design Tool for Use in Improving Hot Roll Slab Recovery', as a Cooperative Agreement TC-02028 with the Alcoa Technical Center (ATC). The objective of the joint project with Alcoa is to develop a numerical modeling capability to optimize the hot rolling process used to produce aluminum plate. Product lost in the rolling process and subsequent recycling, wastes resources consumed in the energy-intensive steps of remelting and reprocessing the ingot. The modeling capability developed by project partners will be used to produce plate more efficiently and with reduced product loss.
Date: September 24, 2004
Creator: Couch, R; Becker, R; Rhee, M & Li, M
Object Type: Report
System: The UNT Digital Library
Factors Affecting the Crevice Corrosion Susceptibility of Alloy 22 (open access)

Factors Affecting the Crevice Corrosion Susceptibility of Alloy 22

The susceptibility or Alloy 22 (N06022) to crevice corrosion may depend on environmental or external factors and metallurgical or internal factors. Some of the most important environmental factors are chloride concentration, inhibitors, temperature and potential. The presence of a weld seam or second phase precipitation in the alloy are classified as internal factors. The localized corrosion resistance of Alloy 22 has been extensively investigated in the last five years, however not all affecting factors were considered in the studies. This paper discusses the current findings regarding the effect of many of these variables on the susceptibility (or resistance) of Alloy 22 to crevice corrosion. The effect of variables such as temperature, chloride concentration and nitrate are rather well understood. However there are only limited or no data regarding effect of other factors such as pH, other inhibitive or deleterious species and type of crevicing material and crevice geometry. There are contradictory results regarding the effect of metallurgical factors such as solution heat treatment.
Date: November 24, 2004
Creator: Rebak, R B
Object Type: Article
System: The UNT Digital Library
Evaporative Evolution of a Na-Cl-NO3-K-Ca-SO4-Mg-Si Brine at 95(degree)C: Experiments and Modeling relevant to Yucca Mountain, Nevada, USA (open access)

Evaporative Evolution of a Na-Cl-NO3-K-Ca-SO4-Mg-Si Brine at 95(degree)C: Experiments and Modeling relevant to Yucca Mountain, Nevada, USA

A synthetic Topopah Spring Tuff water representative of one type of pore water at Yucca Mountain, Nevada (USA) was evaporated at 95 C in a series of experiments to determine the geochemical controls for brines that may form on, and possibly impact upon the long-term integrity of waste containers and drip shields at the designated high-level, nuclear-waste repository. Solution chemistry, condensed vapor chemistry, and precipitate mineralogy were used to identify important chemical divides and to validate geochemical calculations of evaporating water chemistry using a high temperature Pitzer thermodynamic database. The water evolved towards a complex ''sulfate type'' brine that contained about 45 mol% Na, 40 mol% Cl, 9 mol% NO{sub 3}, 5 mol% K, and less than 1 mol% each of SO{sub 4}, Ca, Mg, {Sigma}CO{sub 2}(aq), F, and Si. All measured ions in the condensed vapor phase were below detection limits. The mineral precipitates identified were halite, anhydrite, bassanite, niter and nitratine. Trends in the solution composition and identification of CaSO{sub 4} solids suggest that fluorite, carbonate, sulfate, and magnesium-silicate precipitation control the aqueous solution composition of sulfate type waters by removing fluoride, calcium, and magnesium during the early stages of evaporation. In most cases, the high temperature Pitzer …
Date: August 24, 2004
Creator: Alai, M; Sutton, M & Carroll, S A
Object Type: Article
System: The UNT Digital Library
WxWindows Interface for CALE (open access)

WxWindows Interface for CALE

wxWindows is an Open Source, platform independent, User Interface (UI) which has been in development for over eleven years (http://www.wxwindows.org). Currently wxWindows is actively supported for the Linux/Unix (X11, Motif and GTK+), Mac OS 9 and X, all Win32 OSes, MGL, and OS/2 operating systems. wxWindows is written in C++ using an object oriented programming framework; it is a reasonably lightweight API (called wxWidgets) sitting over the native graphics packages of the various platforms it supports. The original version of CALE was written for the basic target platform of Unix using X11 as the graphics package. There have been separate efforts to port the code to Mac OS 9, Mac OS X, Win32, Windows Services for Unix (SFU) and CygWin. Each of these used a variety of different graphical interface approaches and build/make systems. For instance Windows SFU and CygWin could still only use X11 graphics. So could the Win32 version, if a X11 server library and client software were installed. A native Win32 version of CALE was contemplated, but never started. The Macintosh versions were completed but never widely distributed to the users. Given the growing code version support issues, and the slow deviation from the portable code model …
Date: November 24, 2004
Creator: Amala, P; Egner, C & Hagelberg, J
Object Type: Article
System: The UNT Digital Library
University Reactor Sharing Program (open access)

University Reactor Sharing Program

Research projects supported by the program include items such as dating geological material and producing high current super conducting magnets. The funding continues to give small colleges and universities the valuable opportunity to use the NSC for teaching courses in nuclear processes; specifically neutron activation analysis and gamma spectroscopy. The Reactor Sharing Program has supported the construction of a Fast Neutron Flux Irradiator for users at New Mexico Institute of Mining and Technology and the University of Houston. This device has been characterized and has been found to have near optimum neutron fluxes for A39/Ar 40 dating. Institution final reports and publications resulting from the use of these funds are on file at the Nuclear Science Center.
Date: February 24, 2004
Creator: Reese, W. D.
Object Type: Report
System: The UNT Digital Library
Benchmarking optimization software with COPS 3.0. (open access)

Benchmarking optimization software with COPS 3.0.

The authors describe version 3.0 of the COPS set of nonlinearly constrained optimization problems. They have added new problems, as well as streamlined and improved most of the problems. They also provide a comparison of the FILTER, KNITRO, LOQO, MINOS, and SNOPT solvers on these problems.
Date: May 24, 2004
Creator: Dolan, E. D.; More, J. J. & Munson, T. S.
Object Type: Report
System: The UNT Digital Library
Dihadron correlations at high pT (open access)

Dihadron correlations at high pT

Jet quenching in the matter created in high energy nucleus/nucleus collisions provides a tomographic tool to probe the medium properties. Recent experimental results from the Relativistic Heavy-Ion Collider (RHIC) on characterization of jet production via dihadron correlations at high transverse momentum are reviewed. Expectations from the dihadron measurements for the lower energy {radical}s{sub NN} = 62.4 GeV RHIC run are discussed.
Date: July 24, 2004
Creator: Filimonov, Kirill
Object Type: Article
System: The UNT Digital Library
New physics searches with photons in CDF (open access)

New physics searches with photons in CDF

A brief review of searches for physics beyond the Standard Model with photons using the CDF detector at the Tevatron is given here. These include searches for supersymmetry, extra dimensions, excited electrons and W/Z+{gamma} production, as well as anomalous photon production. Recent results from CDF Run II experiment are presented, but some results from Run I are also reviewed.
Date: May 24, 2004
Creator: Lee, Sungwon
Object Type: Article
System: The UNT Digital Library
HB-Line Special Nuclear Material Campaigns: Model-Based Project Management (open access)

HB-Line Special Nuclear Material Campaigns: Model-Based Project Management

This study is to show how a model was used to enable management to better estimate production capabilities to ensure contract milestones/commitments are met, to cope with fast changing project baselines and project missions, to ensure the project will meet the negotiated throughput, and to eliminate unnecessary but costly design changes.
Date: March 24, 2004
Creator: Chang, Robert
Object Type: Article
System: The UNT Digital Library
Methane hydrate formation and dissociation in a partially saturated sand (open access)

Methane hydrate formation and dissociation in a partially saturated sand

To predict the behavior of hydrate-bearing sediments and the economic extractability of natural gas from reservoirs containing gas hydrates, we need reservoir simulators that properly represent the processes that occur, as well as accurate parameters. Several codes are available that represent some or all of the expected processes, and values for some parameters are available. Where values are unavailable, modelers have used estimation techniques to help with their predictions. Although some of these techniques are well respected, measurements are needed in many cases to verify the parameters. We have performed a series of experiments in a partially water saturated silica sand sample. The series included methane hydrate formation, and dissociation by both thermal stimulation and depressurization. The sample was 7.6 cm in diameter and 25 cm in length. In addition to measuring the system pressure and temperatures at four locations in the sample, we measured local density within the sample using x-ray computed tomography. Our goals in performing the experiment were to gather information for estimating thermal properties of the medium and to examine nonequilibrium processes.
Date: November 24, 2004
Creator: Kneafsey, Timothy J.; Tomutsa, Liviu; Taylor, Charles E.; Gupta, Arvind; Moridis, George; Freifeld, Barry et al.
Object Type: Article
System: The UNT Digital Library
Analytical Method for Measuring Total Protium and Total Deuterium in a Gas Mixture Containing H2, D2, and HD Via Gas Chromatography (open access)

Analytical Method for Measuring Total Protium and Total Deuterium in a Gas Mixture Containing H2, D2, and HD Via Gas Chromatography

A new analytical technique has been developed that measures both total protium (H) and deuterium (D) in a gas mixture containing H2, D2, and HD. This new analytical technique uses a micro gas chromatograph (GC) with two molecular sieve columns. One column uses D2 as the carrier gas and the other uses H2 as the carrier gas. Laboratory tests have shown that when used in this configuration the GC can measure both total protium and total deuterium, each with a sensitivity of less than 20 ppm. This new analytical technique was developed as a result of a request to provide instrumentation to measure the protium and deuterium concentrations at several process points during initial testing of the new hydrogen tritium thermal cycling absorption process columns.
Date: March 24, 2004
Creator: SESSIONS, HENRY
Object Type: Report
System: The UNT Digital Library
A New Method for In-situ Characterization of Important Actinides and Technetium Compounds via Fiberoptic Surface Enhanced Raman Spectroscopy (SERS) (open access)

A New Method for In-situ Characterization of Important Actinides and Technetium Compounds via Fiberoptic Surface Enhanced Raman Spectroscopy (SERS)

This project serves to fill information gap through the development of a novel surface-enhanced Raman scattering (SERS) spectroscopy to selectively and sensitively monitor and characterize the chemical speciation of radionuclides at trace levels. The SERS technique permits both of these measurements to be made simultaneously, and results in significant improvement over current methods in reducing time of analysis, cost, and sample manipulation. Our overall goal is (a) to develop a scientific basis for this new methodology to detect radionuclides via SERS and (b) to rationally synthesize and evaluate novel sol-gel based SERS substrates tailored to sensitively detect and characterize inorganic radionuclides such as TcO{sub 4}{sup -}, actinyl ions (e.g. UO{sub 2}{sup 2+}, NpO{sub 2}{sup +}, and PuO{sub 2}{sup 2+}) and other chemical compounds of interest.
Date: June 24, 2004
Creator: Dai, Sheng & Gu, B.
Object Type: Report
System: The UNT Digital Library
Investigation of Pore Scale Processes That Affect Soil Vapor Extraction (open access)

Investigation of Pore Scale Processes That Affect Soil Vapor Extraction

Dense nonaqueous phase liquid (DNAPL) contamination in the vadose zone is a significant problem at Department of Energy sites. Soil vapor extraction (SVE) is commonly used to remediate DNAPLs from the vadose zone. In most cases, a period of high recovery has been followed by a sustained period of low recovery. This behavior has been attributed to multiple processes including slow interphase mass transfer, retarded vapor phase transport, and diffusion from unswept zones of low permeability. Prior attempts to uncouple and quantify these processes have relied on column experiments, where the effluent concentration was monitored under different conditions in an effort to quantify the contributions from a single process. In real porous media these processes occur simultaneously and are inter-related. Further, the contribution from each of these processes varies at the pore scale and with time. This research aims to determine the pore-scale processes that limit the removal of DNAPL components in heterogeneous porous media during SVE. The specific objectives are to: (1) determine the effect of unswept zones on DNAPL removal during SVE, (2) determine the effect of retarded vapor phase transport on DNAPL removal during SVE, and (3) determine the effect of interphase mass transfer on DNAPL removal …
Date: June 24, 2004
Creator: Valocchi, Albert J.; Werth, Charles J. & Webb, Andrew G.
Object Type: Report
System: The UNT Digital Library
Fast-neutrons incident on gadolinium. (open access)

Fast-neutrons incident on gadolinium.

Reports in the Argonne National Laboratory Nuclear Data and Measurement Series present results of studies in the field of microscopic nuclear data. The primary objective of the series is the dissemination of information in the comprehensive form required for nuclear technology applications. This Series is devoted to: (a) measured microscopic nuclear parameters, (b) experimental techniques and facilities employed in measurements, (c) the analysis, correlation and interpretation of nuclear data, and (d) the compilation and evaluation of nuclear data. Contributions to this Series are reviewed to assure technical competence and, unless otherwise stated, the contents can be formally referenced. This Series does not supplant formal journal publication, but it does provide the more extensive information required for technological applications (e.g., tabulated numerical data) in a timely manner.
Date: May 24, 2004
Creator: Smith, A. B.
Object Type: Report
System: The UNT Digital Library
Axial Pressure Drop Measurements during Pilot-Scale Testing of a Mott Crossflow Filter (open access)

Axial Pressure Drop Measurements during Pilot-Scale Testing of a Mott Crossflow Filter

The Department of Energy selected CSSX as the preferred cesium removal technology for Savannah River Site waste. As a pretreatment step for the CSSX flowsheet, personnel contact the incoming salt solution that contains entrained sludge with MST to adsorb strontium and select actinides. They filter the resulting slurry to remove the sludge and MST. The filtrate receives further treatment to remove cesium in the solvent extraction system. The baseline filtration technology uses a Mott crossflow filter. We conducted pilot-scale crossflow filter testing with simulated SRS high level waste to evaluate the impact of operating parameters on the crossflow filtration process. The tests employed 0.5 micron and 0.1 micron filters. The feed slurries for these tests included simulated sludge plus MST, simulated sludge only, and simulated sludge plus manganese oxide solids. The supernate for these tests consisted of 5.6-6.4 M sodium, average salt solution. During the tests, we measured the axial pressure drop as a function of axial velocity, feed slurry, and insoluble solids concentration. This report documents the axial pressure drop data.
Date: June 24, 2004
Creator: POIRIER, MICHAEL
Object Type: Report
System: The UNT Digital Library