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LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS

Description: Further development of a Large Eddy Simulation (LES) code for the design of advanced gaseous combustion systems is described in this second quarterly report. CFD Research Corporation (CFDRC) is developing the LES module within the parallel, unstructured solver included in the commercial CFD-ACE+ software. CFDRC has implemented and tested Smagorinsky and localized dynamic subgrid turbulence models on a 2.1 million cell DOE-NETL combustor case and a 400,000 cell nonreacting backstep case. Both cases showed good agreement between predicted and experimental results. The large DOE-NETL case results provided better agreement with the measured oscillation frequency than previous attempts because massive parallel computing (on a cluster of 24 pcs) allowed the entire computational domain, including the swirler vanes and fuel spokes, to be modeled. Subgrid chemistry models, including the conditional moment closure (CMC) and linear eddy model (LEM), are being tested and implemented. Reduced chemical mechanisms have been developed for emissions, ignition delay, extinction, and flame propagation using a computer automated reduction method (CARM). A 19-species natural gas mechanism, based on GRI2.11 and Miller-NO{sub x}, was shown to predict rich NO{sub x} emissions better than any previously published mechanisms. The ability to handle this mechanism in CFD-ACE+ was demonstrated by implementing operator splitting and a stiff ODE solver (DVODE). Efficient tabulation methods, including in situ adaptation and artificial neural nets, are being studied and will be implemented in the LES code. The LES combustion code development and testing is on schedule. Next quarter, initial results (including the DOE-NETL unstable combustor) with the CMC and LEM subgrid chemistry models will be completed and summarized.
Date: May 1, 2001
Creator: Cannon, Steve; Adumitroaie, Virgil; McDaniel, Keith & Smith, Cliff
Partner: UNT Libraries Government Documents Department
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DEVELOPMENT AND IMPLEMENTATION OF THE LOS ALAMOS NATIONAL LABORATORY INDEPENDENT SAR REVIEW PROCESS.

Description: Contractor independent review of contractor prepared safety documents has ceased as a requirement under DOE orders. However, a recent study to determine root causes of the poor quality and extremely long approval times for Los Alamos National Laboratory nuclear safety document has identified such a review as a crucial step in ensuring quality. LANL has teamed with the DOE Field Office to reinstate an independent review process modeled after DOE-STD-1104. A review guide has been prepared predicated on the content of DOE-STD-3009. Discipline has been enforced to ensure that comments reflect important issues and that resolution of the comment is possible. Safety management at both LANL and DOE have embraced this concept. This process has been exercised and has resulted in improvements in safety analysis quality and a degree of uniformity between DOE and LANL reviews.
Date: May 1, 2001
Creator: BUECK, J. & MARTH, T.
Partner: UNT Libraries Government Documents Department
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SOME CHEMICAL SAFETY ASPECTS AT LANL

Description: Recently, the Department of Energy (DOE) and its contractors have begun activities to improve the quality and consistency of chemical safety programs throughout the DOE Complex. Several working groups have been formed to assemble a framework for systematically identifying and quantifying chemical hazards and managing chemical risks. At LANL, chemical safety program is implemented through Laboratory Implementation Requirements (LIRs), which are part of the Integrated Safety Management (ISM) plan that includes Safe Work Practices, emphasizing five core functions; define work, identify and analyze hazards, develop and implement controls, perform work safely, and ensure performance. Work is authorized in medium, low and minimal risk areas and not in high risk. Some chemical safety aspects are discussed in terms of chemical hazards and identification, screening, facility hazard categorization--Category A (high), Category B (moderate), and Category C (low), and their requirements in format and content in Authorization Safety Basis documents.
Date: May 1, 2001
Creator: LAUL, J.
Partner: UNT Libraries Government Documents Department
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Cerro Grande Fire- From Wildfire Modeling Through the Fire Aftermath

Description: The Cerro Grande Fire developed from a prescibed burn by the National Park Service at Bandelier National Monument near Los Alamos, New Mexico. When the burn went out of control and became a wildfire, i attracted worldwide attention because it threateed the birthplace of the atomic bomb, Los Alamos National Laboratory (LANL)
Date: May 1, 2001
Creator: Rudell, T. & Gille, R.
Partner: UNT Libraries Government Documents Department
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Superresolution and Synthetic Aperture Radar

Description: Superresolution concepts offer the potential of resolution beyond the classical limit. This great promise has not generally been realized. In this study we investigate the potential application of superresolution concepts to synthetic aperture radar. The analytical basis for superresolution theory is discussed. The application of the concept to synthetic aperture radar is investigated as an operator inversion problem. Generally, the operator inversion problem is ill posed. A criterion for judging superresolution processing of an image is presented.
Date: May 1, 2001
Creator: Dickey, Fred M.; Romero, Louis & Doerry, Armin W.
Partner: UNT Libraries Government Documents Department
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Comparison of Near-field and Far-field Air Monitoring of Plutonium-contaminated Soils from the Tonopah Test Range, Nevada

Description: Operation Roller Coaster, a series of nuclear material dispersal experiments, resulted in three areas (Clean Slates 1, 2, and 3) of widespread surface soil plutonium (Pu) contamination on the Tonopah Test Range (TTR), located 225 miles northwest of Las Vegas, Nevada. The State's Division of Environmental Protection raised concerns that dispersal of airborne Pu particles from the sites could result in undetected deposition further downwind that the background monitoring stations. Air monitoring data from different distances from the Clean Slate sites but during the same period of time were compared. From the available data, there is no indication that airborne PM10 particles are being transported to the farther distance,however, the data are statistically insufficient to conclude whether there is a difference in transport of respirable Pu particles to the closer verses the farther sites from the Clean Slate sites.
Date: May 1, 2001
Creator: Bowen, John L. & Shafer, David S.
Partner: UNT Libraries Government Documents Department
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A NEW INTERPHASE FORCE IN TWO-PHASE FLUIDIZED BEDS

Description: Mesoscale structures such as particle clusters have been observed both in experiments and in numerical simulations of circulating fluidized beds. In a numerical simulation, in order to account for the effects of such mesoscale structures, the computational grids have to be fine enough. The use of such fine grids is impractical in engineering applications due to excessive computational costs. To predict the macroscopic behavior of a fluidized bed with reasonable computation cost, they perform a second average over the averaged equations for two-phase flows. A mesoscale inter-phase exchange force is found to be the correlation of the particle volume fraction and the pressure gradient. This force is related to the mesoscale added mass of the two-phase flow. Typically, added mass for particle scale interactions is negligible in gas-solid flows since the gas density is small compared to density of solid particles. However, for a mesoscale structure, such as a bubble, the surrounding media is the mixture of gas and particles. The surrounding fluid density experienced by the mesoscale structure is the density of the surrounding mixture. Therefore, the added mass of a mesoscale structure, such as bubbles, cannot be neglected. The property of this new force is studied based on the numerical simulation of a fluidized bed using high grid resolution. It is shown that this force is important in the region where the particle volume fraction is high. The effects of the inhomogeneity to the interphase drag are also studied.
Date: May 1, 2001
Creator: ZHANG, D. & VANDERHEYDEN, W.
Partner: UNT Libraries Government Documents Department
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The Concentration of (236)Pu Daughters in Plutonium for Application to MOX Production from Plutonium from Dismantled US Nuclear Weapons

Description: The isotope {sup 236}Pu in the weapons-grade plutonium to be used in the US MOX (mixed-oxide) plant is of concern because the daughter products of {sup 236}Pu are sources of high-energy gamma rays. The {sup 208}Tl daughter of {sup 236}Pu emits intense, high-energy gamma rays that are important for radiation exposure calculations for plant design. It is generally thought that the concentrations of {sup 236}Pu and its daughters are well below 10{sup {minus}10}, but these concentrations are generally below the detection limits of most analytical techniques. One technique that can be used to determine the concentration {sup 208}Tl is the direct measurement of the intensity of the {sup 208}Tl gamma rays in the gamma-ray spectrum from plutonium. Thallium-208 will be in equilibrium with {sup 228}Th, and may very well be in equilibrium with {sup 232}U for most aged plutonium samples. We have used the FRAM isotopic analysis software to analyze dozens of archived high-resolution gamma ray spectra from various samples of US and foreign plutonium. We are able to quantify the ratio of minor isotopes with measurable gamma-ray emissions to the major isotope of plutonium and hence, through the measurement of the plutonium isotopic distribution of the sample, to elemental plutonium itself. Excluding items packaged in fluoropolymer vials, all samples analyzed with {sup 240}Pu < 9% gave {sup 228}Th/Pu ratios < 3.4 e-012 and all samples of US-produced plutonium, including {sup 240}Pu values up to 16.4%, gave {sup 228}Th/Pu ratios < 9.4 e-012. None of these values is significant from a radiation dose standpoint.
Date: May 1, 2001
Creator: Sampson, T.E. & Cremers, T.L.
Partner: UNT Libraries Government Documents Department
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Progress with the SNS front-end systems

Description: The Front-End Systems (FES) of the Spallation Neutron Source (SNS) project have been described in detail elsewhere [1]. They comprise an rf-driven H{sup {minus}} ion source, electrostatic LEBT, four-vane RFQ, and an elaborate MEBT. These systems are planned to be delivered to the SNS facility in Oak Ridge in June 2002. This paper discusses the latest design features, the status of development work, component fabrication and procurements, and experimental results with the first commissioned beamline elements.
Date: May 1, 2001
Creator: Keller, R.; Abraham, W.; Ayers, J. J.; Cheng, D. W.; Cull, P.; DiGennaro, R. et al.
Partner: UNT Libraries Government Documents Department
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Effective field theory for the small-x evolution

Description: The small-x behavior of structure functions in the saturation region is determined by the non-linear generalization of the BFKL equation. I suggest the effective field theory for the small-x evolution which solves formally this equation. The result is the 2+1 functional integral for the structure functions at small x.
Date: May 1, 2001
Creator: Balitsky, Ian
Partner: UNT Libraries Government Documents Department
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CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

Description: Electrobalance studies of calcination and carbonation of sodium bicarbonate materials were conducted at Louisiana State University. Calcination in an inert atmosphere was rapid and complete at 120 C. Carbonation was temperature dependent, and both the initial rate and the extent of reaction were found to decrease as temperature was increased between 60 and 80 C. A fluidization test apparatus was constructed at RTI and two sodium bicarbonate materials were fluidized in dry nitrogen at 22 C. The bed was completely fluidized at between 9 and 11 in. of water pressure drop. Kinetic rate expression derivations and thermodynamic calculations were conducted at RTI. Based on literature data, a simple reaction rate expression, which is zero order in carbon dioxide and water, was found to provide the best fit against reciprocal temperature. Simulations based on process thermodynamics suggested that approximately 26 percent of the carbon dioxide in flue gas could be recovered using waste heat available at 240 C.
Date: May 1, 2001
Creator: Green, David A.; Turk, Brian S.; Gupta, Raghubir P.; Lopez-Ortiz, Alejandro; Harrison, Douglas P. & Liang, Ya
Partner: UNT Libraries Government Documents Department
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Small fatigue cracks: mechanics, mechanisms and engineering applications

Description: Damage-tolerant design and life-prediction methodologies have been practiced for metallic structures for decades, although their application to brittle materials, such as ceramics, and intermetallic alloys, still poses particular problems, primarily because of their extreme flaw-sensitivity.
Date: May 1, 2001
Creator: Ritchie, R. O. & Peters, J. O.
Partner: UNT Libraries Government Documents Department
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Laboratory Directed Research and Development FY 2000 Annual Progress Report

Description: This is the FY00 Annual Progress report for the Laboratory Directed Research and Development (LDRD) Program at Los Alamos National Laboratory. It gives an overview of the LDRD Program, summarizes progress on each project conducted during FY00, characterizes the projects according to their relevance to major funding sources, and provides an index to principal investigators. Project summaries are grouped by LDRD component: Directed Research and Exploratory Research. Within each component, they are further grouped into the ten technical categories: (1) atomic, molecular, optical, and plasma physics, fluids, and beams, (2) bioscience, (3) chemistry, (4) computer science and software engineering, (5) engineering science, (6) geoscience, space science, and astrophysics, (7) instrumentation and diagnostics, (8) materials science, (9) mathematics, simulation, and modeling, and (10) nuclear and particle physics.
Date: May 1, 2001
Creator: Laboratory, Los Alamos National
Partner: UNT Libraries Government Documents Department
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STRUCTURAL HEALTH MONITORING OF WELDED CONNECTIONS

Description: Structural health monitoring is the implementation of a damage detection strategy for aerospace, civil and mechanical engineering infrastructure. Typical damage experienced by this infrastructure might be the development of fatigue cracks, degradation of structural connections, or bearing wear in rotating machinery. The goal of the research effort reported herein is to develop a robust and cost-effective monitoring system for welded beam-column connections in a moment resisting frame structure. The structural health monitoring solution for this application will integrate structural dynamics, wireless data acquisition, local actuation, micro-electromechanical systems (MEMs) technology, and statistical pattern recognition algorithms. This paper provides an example of the integrated approach to structural health monitoring being undertaken at Los Alamos National Laboratory and summarizes progress to date on various aspects of the technology development.
Date: May 1, 2001
Creator: SOHN, H.; FARRAR, C.; FUGATE, M. & CZARNECKI, J.
Partner: UNT Libraries Government Documents Department
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YIELD STRESS ANOMALIES, DISLOCATION CORE STRUCTURES AND SUBSTITUTIONAL ALLOYING IN MOLYBDENUM DISILICIDE

Description: A brief overview of the temperature dependence of yield strength for the different slip systems of MoSi{sub 2} is presented and mechanisms for the yield stress anomaly are discussed. Recent results on the atomistic simulation of the dislocation core structures and mobility are presented next. Finally, we present experimental results on substitutional alloying of polycrystalline MoSi{sub 2} with 1-2 at.% Re, Nb and Al. Re resulted in an order of magnitude increase in compressive strength at 1600 C, Al caused solution softening at near-ambient temperatures, and Nb caused softening at low temperatures and hardening at high temperatures. The quaternary MoSi{sub 2}-Re-Al alloys showed strengthening at elevated temperatures and reduction in flow stress with enhanced plasticity at near-ambient temperatures. The mechanisms of solution hardening and softening are discussed using insight from transmission electron microscopy observations of the dislocation substructures and atomistic simulation results.
Date: May 1, 2001
Creator: MISRA, A.; MITCHELL, T.; BASKES, M. & AL, ET
Partner: UNT Libraries Government Documents Department
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DEVELOPMENT OF ROOM TEMPERATURE IONIC LIQUIDS FOR APPLICATIONS IN ACTINIDE CHEMISTRY

Description: One area of on-going research in our group at Los Alamos National Laboratory is directed toward characterization of the basic coordination chemistry and electrochemical behavior of f-element ions dissolved in room temperature ionic liquids (RTILs). The ultimate goal of this work is to introduce advanced, environmentally sustainable, nuclear processing and purification strategies into both the DOE complex and the civilian nuclear industry. Efforts to develop ambient temperature electrorefining and/or electrowinning technologies are focused on the design of ionic liquids characterized by extended cathodic stability. In this chapter a summary of the synthesis, physical properties and electrochemical behavior of the ionic liquids used in this work is presented. The feasibility of efficient electrochemical production of high electropositive metals is demonstrated through reversible plating and stripping of sodium and potassium metals.
Date: May 1, 2001
Creator: OLDHAM, W.; COSTA, D. & SMITH, W.
Partner: UNT Libraries Government Documents Department
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Electron Correlation and Plutonium Phase Diagrams

Description: The energy and entropy curves for unalloyed Pu mark the extent of our progress toward an understanding of the phase diagrams presented at the beginning of the paper; it is clear that there is still a long way to go. It would be desirable to evaluate the vibrational thermodynamic functions from measured phonon spectra. However, this may require the growth of single crystals, if the PDF method using powder diffraction proves impractical for Pu. The measurement of inelastic phonon densities of states from polycrystalline samples might be a practical method for all phases of Pu. Estimates of the electronic contributions to the thermodynamics have been derived from the work of Wallace (1998). It would be of interest to compare these with theoretical estimates to evaluate the role of electron correlation in the phase stability of plutonium metal. As emphasized by Wallace, this will be an ''enormous challenge'' to electronic structure theory. In particular, we need a more predictive understanding of how narrow bands in Pu stabilize idiosyncratic crystal structures (Soederlind et al., 1995 and Soederlind, 1998) Materials Properties.
Date: May 1, 2001
Creator: Lawson, A.; Roberts, J. & Al, Et
Partner: UNT Libraries Government Documents Department
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A ghost cell expansion method for reducing communications in solving PDE problems

Description: In solving Partial Differential Equations, such as the Barotropic equations in ocean models, on Distributed Memory Computers, finite difference methods are commonly used. Most often, processor subdomain boundaries must be updated at each time step. This boundary update process involves many messages of small sizes, therefore large communication overhead. Here we propose a new approach which expands the ghost cell layers and thus updates boundaries much less frequently ---reducing total message volume and grouping small messages into bigger ones. Together with a technique for eliminating diagonal communications, the method speedup communication substantially, up to 170%. We explain the method and implementation in details, provide systematic timing results and performance analysis on Cray T3E and IBM SP.
Date: May 1, 2001
Creator: Ding, Chris H.Q. & He, Yun
Partner: UNT Libraries Government Documents Department
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EFFECTS OF MINERALOGY, GRAIN SIZE, AND SOLUTION COMPOSITION ON LITHIUM SORPTION TO SATURATED ALLUVIUM SOUTH OF YUCCA MOUNTAIN, NEVADA

Description: Lithium is used frequently as a surrogate for cationic radionuclides such as NpO{sub 2}{sup +} in field and laboratory settings. Current plans include the use of Li{sup +} as a reactive tracer in field tracer testing in the saturated alluvium south of Yucca Mountain, NV, site of a potential high-level nuclear waste. Characterization of the alluvial material for grain size, mineralogy, cation exchange capacity (CEC), and surface area yields data that is compared with lithium batch sorption as a first step in inferring radionuclide transport behavior. This research will be used to help assess performance of the potential repository.
Date: May 1, 2001
Creator: SULLIVAN, E.; REIMUS, P. & AL, ET
Partner: UNT Libraries Government Documents Department
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Direct Methanol Fuel Cells at Reduced Catalyst Loadings

Description: We focus in this paper on the reduction of catalyst loading in direct methanol fuel cells currently under development at Los Alamos National Laboratory. Based on single-cell DMFC testing, we discuss performance vs. catalyst loading trade-offs and demonstrate optimization of the anode performance. We also show test data for a short five-cell DMFC stack with the average total platinum loading of 0.53 mg cm{sup {minus}2} and compare performance of this stack with the performance of a single direct methanol fuel cell using similar total amount of precious metal.
Date: May 1, 2001
Creator: Zelenay, Piotr; Guyon, Francois & Gottesfeld, Shimshon
Partner: UNT Libraries Government Documents Department
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CALCULATING ACCURATE SHUFFLER COUNT RATES WITH APPLICATIONS

Description: Shufflers are used to assay uranium and other fissile elements in bulk and waste quantities. They normally require physical calibration standards to achieve the most-accurate results, but such standards are generally rare and expensive, so inappropriate standards are often used out of necessity. This paper reports on a new technique that has been developed to calculate accurate count rates, in effect simulating physical standards with rapid and inexpensive calculations. The technique has been benchmarked on existing oxide and metallic standards, used to study a variety of conditions for which standards do not exist, and applied to inventory items needing verification measurements even though appropriate physical standards do not exist.
Date: May 1, 2001
Creator: RINARD, P. M.
Partner: UNT Libraries Government Documents Department
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Review of Wildfire Effects on Chemical Water Quality

Description: The Cerro Grande Fire of May 2000 burned almost 43,000 acres of forested land within the Pajarito Plateau watershed in northern New Mexico. Runoff events after the fire were monitored and sampled by Los Alamos National Laboratory. Changes in the composition of runoff water were noted when compared to runoff water composition of the previous 20 years. In order to understand the chemical water quality changes noted in runoff water after the Cerro Grande Fire, a summary of the reported effects of fire on runoff water chemistry and on soils that contribute to runoff water chemistry was compiled. The focus of this report is chemical water quality, so it does not address changes in sediment transport or water quantity associated with fires. Within the general inorganic parameters, increases of dissolved calcium, magnesium, nitrogen, phosphorus, and potassium and pH in runoff water have been observed as a result of fire. However, the dissolved sodium, carbon, and sulfate have been observed to increase and decrease as a result of fire. Metals have been much less studied, but manganese, copper, zinc, and cesium-137 have been observed to increase as a result of fire.
Date: May 1, 2001
Creator: Bitner, Kelly; Gallaher, Bruce & Mullen, Ken
Partner: UNT Libraries Government Documents Department
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