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On the structure, propagation, and stabilization of laminar premixed flames. Final report

Description: The primary objective of the funded program was to qualitatively understand and quantitatively determine the structure and dynamics of laminar premixed flames. The investigation was conducted using laser-based experimentation, computational simulation with detailed chemistry and transport, and activation energy asymptotic analysis. Highlights of accomplishments were discussed in the annual reports submitted to the program monitor for this project. Details are reported in the thirty journal publications cited in the journal article list which is the major component of this final report.
Date: July 1999
Creator: Law, Chung K.
Partner: UNT Libraries Government Documents Department

Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport (Partnerships in Computational Science)

Description: The over-reaching goal of the Groundwater Grand Challenge component of the Partnership in Computational Science (PICS) was to develop and establish the massively parallel approach for the description of groundwater flow and transport and to address the problem of uncertainties in the data and its interpretation. This necessitated the development of innovative algorithms and the implementation of massively parallel computational tools to provide a suite of simulators for groundwater flow and transport in heterogeneous media. This report summarizes the activities and deliverables of the Princeton University component of the Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1998. Seven institutions were primarily involved in this project: Brookhaven National Laboratory, Oak Ridge National Laboratory, Princeton University, SUNY at Stony Brook, Texas A&M University, The University of South Carolina, and the University of Texas at Austin, with contributing efforts from the Westinghouse Savannah River Technology Center. Each institution had primary responsibility for specific research components, but strong collaboration among all institutions was essential for the success of the project and in producing the final deliverables. PICS deliverables include source code for the suite of research simulators and auxiliary HPC tools, associated documentation, and test problems. These materials will be available as indicated from each institution's web page or from the Center for Computational Sciences Oak Ridge National Laboratory in January 1998.
Date: March 11, 1999
Creator: Celia, M. A.
Partner: UNT Libraries Government Documents Department

CONCEPTUAL DESIGN OF OPTIMIZED FOSSIL ENERGY SYSTEMS WITH CAPTURE AND SEQUESTRATION OF CARBON DIOXIDE

Description: In this second semi-annual progress report, we describe research results from an ongoing study of fossil hydrogen energy systems with CO{sub 2} sequestration. This work was performed under NETL Award No. DE-FC26-02NT41623, during the six-month period March 2003 through September 2003. The primary objective of the study is to better understand system design issues and economics for a large-scale fossil energy system co-producing H{sub 2} and electricity with CO{sub 2} sequestration. This is accomplished by developing analytic and simulation methods for studying the entire system in an integrated way. We examine the relationships among the different parts of a hydrogen energy system, and attempt to identify which variables are the most important in determining both the disposal cost of CO{sub 2} and the delivered cost of H{sub 2}. A second objective is to examine possible transition strategies from today's energy system toward one based on fossil-derived H{sub 2} and electricity with CO{sub 2} sequestration. We are carrying out a geographically specific case study of development of a fossil H{sub 2} system with CO{sub 2} sequestration, for the Midwestern United States, where there is presently substantial coal conversion capacity in place, coal resources are plentiful and potential sequestration sites in deep saline aquifers are widespread.
Date: December 2003
Creator: Ogden, Joan M.
Partner: UNT Libraries Government Documents Department

COARSE-GRID SIMULATION OF REACTING AND NON-REACTING GAS-PARTICLE FLOWS

Description: Many processes involved in coal utilization involve handling of fine particles, their pneumatic transport, and their reactions in fluidized beds, spouted beds and circulating fluidized beds. One of the factors limiting our ability to simulate these processes is the hydrodynamics encountered in them. Two major issues that contribute to this limitation are lack of good and computationally expedient models for frictional interaction between particles, and models to capture the consequences of mesoscale structures that are ubiquitous in gas-solid flows. This project has focused on the development of these models through a combination of computer simulations and experiments. The principal goal of this project, funded under the ''DOE Vision 21 Virtual Demonstration Initiative'' is better simulation of circulating fluidized bed performance. The principal challenge funded through this cooperative agreement is to devise sound physical models for the rheological characteristics of the gas-particle mixtures and implement them in the open-domain CFD code MFIX. During the course of this project, we have made the following specific advances. (a) We have demonstrated unequivocally that sub-grid models are essential to capture, even qualitatively correctly, the macroscale flow structures in gas-particle flows in vertical risers. To this end, we developed sub-grid models of different levels of detail and exposed the sensitivity of the results obtained in coarse-grid simulations of gas-particle flow in a riser to the level of sophistication of the sub-grid models. (b) We have demonstrated that sub-grid model for the fluid-particle drag force is the most important additional feature and that the corrections for the granular phase viscosity and pressure are of secondary importance. We have also established that sub-grid models for dispersion of heat and mass are of secondary importance only. (c) We have brought forth the general character of the sub-grid model for the drag force. (d) We have performed for the ...
Date: October 2004
Creator: Sundaresan, Sankaran
Partner: UNT Libraries Government Documents Department

Contaminant Organic Complexes: Their Structure and Energetics in Surface Decontamination Processes

Description: Siderophores are biological macromolecules (400-2000 Da) released by bacteria in iron limiting situations to sequester Fe from iron oxyhydroxides and silicates in the natural environment. These molecules contain hydroxamate and phenolate functional groups, and exhibit very high affinity for Fe{sup 3+}. While several studies were conducted to understand the behavior of siderophores and their application to the metal sequestration and mineral dissolution, only a few of them have examined the molecular structure of siderophores and their interactions with metals and mineral surfaces in aqueous solutions. Improved understanding of the chemical state of different functional moieties in siderophores can assist in the application of these biological molecules in actinide separation, sequestration and decontamination processes. The focus of our research group is to evaluate the (a) functional group chemistry of selected siderophores and their metal complexes in aqueous solutions, and (b) the nature of siderophore interactions at the mineral-water interfaces. We selected desferrioxamine B (desB), a hydroxamate siderophore, and its small structural analogue, acetohydroxamic acid (aHa), for this investigation. We examined the functional group chemistry of these molecules as a function of pH, and their complexation with aqueous and solid phase Fe(III). For solid phase Fe, we synthesized all naturally occurring Fe(III)-oxyhydroxides (goethite, lepidocrocite, akaganeite, feroxyhite) and hematite. We also synthesized Fe-oxides (goethite and hematite) of different sizes to evaluate the influence of particle size on mineral dissolution kinetics. We used a series of molecular techniques to explore the functional group chemistry of these molecules and their complexes. Infrared spectroscopy is used to specifically identify the variations in oxime group as a function of pH and Fe(III) complexation. Resonance Raman spectroscopy was used to evaluate the nature of hydroxamate binding in the case of Fe(III)-siderophore complexes and model ligands. Soft and hard X-ray spectroscopy techniques were used to examine the electronic structure ...
Date: December 13, 2005
Creator: Myneni, Satish C. B.
Partner: UNT Libraries Government Documents Department

Precipitation and Deposition of Aluminum-Containing Phases in Tank Wastes

Description: Aluminum-containing phases compose the bulk of solids precipitating during the processing of radioactive tank wastes. Processes designed to minimize the volume of high-level waste through conversion to glassy phases require transporting waste solutions near-saturated with aluminum-containing species from holding tank to processing center. The uncontrolled precipitation within transfer lines results in clogged pipes and lines and fouled ion exchangers, with the potential to shut down processing operations.
Date: January 12, 2005
Creator: Dabbs, Daniel M. & Aksay, Ilhan A.
Partner: UNT Libraries Government Documents Department

COARSE-GRID SIMULATION OF REACTING AND NON-REACTING GAS-PARTICLE FLOWS

Description: The principal goal of this project, funded under the ''DOE Vision 21 Virtual Demonstration Initiative'' is virtual demonstration of circulating fluidized bed performance. We had proposed a ''virtual demonstration tool'', which is based on the open-domain CFD code MFIX. The principal challenge funded through this grant is to devise and implement in this CFD code sound physical models for the rheological characteristics of the gas-particle mixtures. Within the past year, which was the third year of the project, we have made the following specific advances. (a) We have completed a study of the impact of sub-grid models of different levels of detail on the results obtained in coarse-grid simulations of gas-particle flow. (b) We have also completed a study of a model problem to understand the effect of wall friction, which was proved in our earlier work to be very important for stable operation of standpipes in a circulating fluidized bed circuit. These are described in a greater detail in this report.
Date: March 2004
Creator: Sundaresan, Sankaran
Partner: UNT Libraries Government Documents Department

CONCEPTUAL DESIGN OF OPTIMIZED FOSSIL ENERGY SYSTEMS WITH CAPTURE AND SEQUESTRATION OF CARBON DIOXIDE

Description: In this semi-annual progress report, we describe research results from an ongoing study of fossil hydrogen energy systems with CO{sub 2} sequestration. This work was performed under NETL Award No. DE-FC26-02NT41623, during the six-month period September 2002 through March 2003. The primary objective of the study is to better understand system design issues and economics for a large-scale fossil energy system co-producing H{sub 2} and electricity with CO{sub 2} sequestration. This is accomplished by developing analytic and simulation methods for studying the entire system in an integrated way. We examine the relationships among the different parts of a hydrogen energy system, and attempt to identify which variables are the most important in determining both the disposal cost of CO{sub 2} and the delivered cost of H{sub 2}. A second objective is to examine possible transition strategies from today's energy system toward one based on fossil-derived H{sub 2} and electricity with CO{sub 2} sequestration. We are carrying out a geographically specific case study of development of a fossil H{sub 2} system with CO{sub 2} sequestration, for the Midwestern United States, where there is presently substantial coal conversion capacity in place, coal resources are plentiful and potential sequestration sites in deep saline aquifers are widespread.
Date: June 26, 2003
Creator: Ogden, Joan M.
Partner: UNT Libraries Government Documents Department

Corridor One: An Integrated Distance Visualization Environment for SSI and ASCI Applications

Description: The Corridor One project is a three-year integrated research project that combines the forces of six leading-edge laboratory and university groups working in the area of visualization, distributed computing and high-performance networking to develop and to deploy the most advanced, integrated distance visualization environment.
Date: July 15, 1999
Creator: Li, K.; Finkelstein, A. & Funkhouser, T.
Partner: UNT Libraries Government Documents Department

CONCEPTUAL DESIGN OF OPTIMIZED FOSSIL ENERGY SYSTEMS WITH CAPTURE AND SEQUESTRATION OF CARBON DIOXIDE

Description: In this third semi-annual progress report, we describe research results from an ongoing study of fossil hydrogen energy systems with CO{sub 2} sequestration. This work was performed under NETL Award No. DE-FC26-02NT41623, during the six-month period September 2003 through March 2004. The primary objective of the study is to better understand system design issues and economics for a large-scale fossil energy system co-producing H{sub 2} and electricity with CO{sub 2} sequestration. This is accomplished by developing analytic and simulation methods for studying the entire system in an integrated way. We examine the relationships among the different parts of a hydrogen energy system, and attempt to identify which variables are the most important in determining both the disposal cost of CO{sub 2} and the delivered cost of H{sub 2}. A second objective is to examine possible transition strategies from today's energy system toward one based on fossil-derived H{sub 2} and electricity with CO{sub 2} sequestration. We are carrying out a geographically specific case study of development of a fossil H{sub 2} system with CO{sub 2} sequestration, for the Midwestern United States, where there is presently substantial coal conversion capacity in place, coal resources are plentiful and potential sequestration sites in deep saline aquifers are widespread.
Date: May 1, 2004
Creator: Ogden, Joan M.
Partner: UNT Libraries Government Documents Department

The symbiosis of carbon-dioxide sequestration and hydrogen fuel: what is its significance for the long-term global energy system. Final progress report July 1998 - July 2000

Description: This study examined the implications of the ''fuel decarbonization/carbon sequestration'' strategy for the world energy system.
Date: September 8, 2000
Creator: Socolow, Robert H.; Ogden, Joan M. & Williams, Robert H.
Partner: UNT Libraries Government Documents Department

Trace Metal Bioremediation: Assessment of Model Components from Laboratory and Field Studies to Identify Critical Variables

Description: The objective of this project was to gain an insight into the modeling support needed for the understanding, design, and operation of trace metal/radionuclide bioremediation. To achieve this objective, a workshop was convened to discuss the elements such a model should contain. A ''protomodel'' was developed, based on the recommendations of the workshop, and was used to perform sensitivity analysis as well as some preliminary simulations in support for bioremediation test experiments at UMTRA sites. To simulate the numerous biogeochemical processes that will occur during the bioremediation of uranium contaminated aquifers, a time-dependent one-dimensional reactive transport model has been developed. The model consists of a set of coupled, steady state mass balance equations, accounting for advection, diffusion, dispersion, and a kinetic formulation of the transformations affecting an organic substrate, electron acceptors, corresponding reduced species, and uranium. This set of equations is solved numerically, using a finite element scheme. The redox conditions of the domain are characterized by estimating the pE, based on the concentrations of the dominant terminal electron acceptor and its corresponding reduced specie. This pE and the concentrations of relevant species are passed to a modified version of MINTEQA2, which calculates the speciation and solubilities of the species of interest. Kinetics of abiotic reactions are described as being proportional to the difference between the actual and equilibrium concentration. A global uncertainty assessment, determined by Random Sampling High Dimensional Model Representation (RS-HDMR), was performed to attain a phenomenological understanding of the origins of output variability and to suggest input parameter refinements as well as to provide guidance for field experiments to improve the quality of the model predictions. Results indicated that for the usually high nitrate contents found ate many DOE sites, overall bioremediation of trace metals was highly sensitive to the formulation of the denitrification process. Simulations were ...
Date: February 14, 2003
Creator: Jaffe, Peter & Rabitz, Herschel
Partner: UNT Libraries Government Documents Department

Biological physics

Description: Major goals of biological physics are the understanding of biological systems in physical terms and the study of concepts and laws of complex systems.
Date: September 24, 1998
Partner: UNT Libraries Government Documents Department

Enhancement of Bacterial Transport in Aerobic and Anaerobic Environments: Assessing the Effect of Metal Oxide Chemical Heterogeneities

Description: The goal of our research was to understand the fundamental processes that control microbial transport in physically and chemically heterogeneous aquifers and from this enhanced understanding determine the requirements for successful, field-scale delivery of microorganisms to metal contaminated subsurface sites. Our specific research goals were to determine; (1) the circumstances under which the preferential adsorption of bacteria to Fe, Mn, and Al oxyhydroxides influences field-scale bacterial transport, (2) the extent to which the adhesion properties of bacterial cells affect field-scale bacterial transport, (3) whether microbial Fe(III) reduction can enhance field-scale transport of Fe reducing bacteria (IRB) and other microorganisms and (4) the effect of field-scale physical and chemical heterogeneity on all three processes. Some of the spin-offs from this basic research that can improve biostimulation and bioaugmentation remediation efforts at contaminated DOE sites have included; (1) new bacterial tracking tools for viable bacteria; (2) an integrated protocol which combines subsurface characterization, laboratory-scale experimentation, and scale-up techniques to accurately predict field-scale bacterial transport; and (3) innovative and inexpensive field equipment and methods that can be employed to enhance Fe(III) reduction and microbial transport and to target microbial deposition under both aerobic and anaerobic conditions.
Date: September 30, 2005
Creator: Onstott, T.C.
Partner: UNT Libraries Government Documents Department

Hydrogen as an Indicator to Assess Biological Activity During Trace-Metal Bioremediation

Description: Trace-metal and/or radionuclide bioremediation schemes require that specific redox conditions be achieved at given zones of an aquifer. Tools are therefore needed to identify the terminal electron acceptor processes (TEAPs) that are being achieved during bioremediation in an aquifer. Dissolved hydrogen (H2) concentrations have been shown to correlate with specific TEAPs during bioremediation in an aquifer. Theoretical analysis has shown that these steady-state H2 levels are solely dependent upon the physiological parameters of the hydrogen-consuming microorganisms, with H2 concentrations increasing as each successive TEAP yields less energy for bacterial growth. The objective of this research was to determine if H2 can still be used as an indicator of TEAPs during a uranium bioremediation scheme where an organic substrate is injected into the subsurface and organisms may consume H2 and carbon simultaneously. In addition, the effect of iron bioavailability on H2 concentrations during iron reduction was observed. The first phase of research determined the effect of a competing electron donor (acetate) on the kinetics of H2 utilization by Geobacter sulfurreducens in batch cultures under iron reducing conditions. The results indicate that, though the Monod kinetic coefficients describing the rate of H2 utilization under iron-reducing conditions correlate energetically with the coefficients found in previous experiments under methanogenic and sulfate-reducing conditions, conventionally measured growth kinetics do not predict the steady state H2 levels typical for each TEAP. In addition, with acetate and H2 as simultaneous electron donors, there is slight inhibition between the two electron donors for G. sulfurreducens, and this can be modeled through competitive inhibition terms in the classic Monod formulation, resulting in slightly higher H2 concentrations under steady state conditions in the presence of acetate. This dual-donor model indicates that the steady state H2 concentration in the presence of an organic as electron donor is not only dependent on the ...
Date: September 27, 2005
Creator: Peter R. Jaffe, John Komlos, Derick Brown
Partner: UNT Libraries Government Documents Department

Hydration reactions of C/sub 3/A contained in an unusual flyash

Description: Flyashes produced from certain lignite and sub-bituminous coals have high contents of analytical CaO, presumably derived from limestone within the coal deposits. In the US a special category, Class C flyash has been designated for these materials. The mineralogy of the non-glassy portions of some of these flyashes is different from conventional flyashes, and in the material described C/sub 3/A, free lime, and anhydrite are all present. The flyash sets rapidly when mixed with water, and produces ettringite and C/sub 4/ASH/sub 12/. The unique spherical morphology of the flyash grains makes the morphological relationships between the hydration products and the unhydrated material unusually clear. The early reactions are similar to those of C/sub 3/A in portland cement, and the ash might serve as a useful model system for the study of the influence of various admixtures and other substances on C/sub 3/A reactions and setting behavior. Presumably ettringite and C/sub 4/ASH/sub 12/ are also produced when flyashes similar to the one studied are incorporated in concrete, and their production should enhance early strength development.
Date: January 1, 1980
Creator: Diamond, S.
Partner: UNT Libraries Government Documents Department

Study of electrons photoemitted from field emission tips. Progress report, July 1, 1979-March 1, 1980

Description: Photo-induced field emission is a technique which studies electrons that have been photoemitted from a field emission tip. This new experimental method promises to combine the proven utility of both field emission and photoemission for investigating the electronic states near a metal surface. The primary objective of the research being performed is to investigate photo-induced field emitted electrons using a tuneable cw dye laser. To fully exploit this continuously tuneable photon source, a differential energy analyzer is being constructed to allow energy resolved measurements of the photo-field emitted electrons. This report describes the progress made in implementing experiments on photo-induced field emission from July 1979 to March 1980.
Date: February 1, 1980
Creator: Reifenberger, R.
Partner: UNT Libraries Government Documents Department

Radiochemical investigations of nuclear properties. Progress report, January 1, 1979-December 31, 1979. [Purdue Univ]

Description: Investigations of the high-spin level spectra of the nuclei /sup 200/Pb, /sup 202/Pb, and /sup 188/Os were completed, and the results are summarized. The results of collaborative studies of high-spin excitations in /sup 147/Tb and /sup 148/Tb are also briefly reported. New studies of A approx. 150 nuclei at very high angular momenta with heavy-ion beams from the Argonne Tandem-Linac were started. 5 figures, 1 table.
Date: January 1, 1980
Creator: Daly, P.J.
Partner: UNT Libraries Government Documents Department

Systems studies of coal-conversion processes using a reference simulator. Final report, March 12, 1976-August 12, 1979

Description: Methodology and general purpose software were developed which do allow computer-aided design and analysis of large scale coal conversion processes. The LINBAL package for larger scale balance calculations was demonstrated to be quick and efficient in solving problems involving over 100 streams, 20 species, and 80 or more flowsheet units. The LSP simulation package embodies constraint handling, recycle calculation, and information management features which are an advance of the state of the art. The two level strategy available in LSP was demonstrated on a reasonable sized simulation and shown to result in a 1/3 reduction of CPU time over conventional calculation strategies. The Physical Properties Package was used in all of the simulation models developed under this project and proved to be satisfactory within the limits of the thermodynamic correlations and estimation methods which are encoded. Although the package is largely conventional in overall design, it does employ features which make it convenient to use both within LSP and on a stand-along basis. The PCOST package represents a new approach to the design of this type of program. The program has proved to be simple to use, robust, and accurate within the limitations of the literature cost correlations that it contains. In summary, the project has accomplished its primary objectives. However, time and fiscal limitation did not permit the completion of an adequate slate of case studies.
Date: December 1, 1979
Creator: Reklaitis, G.V.; Sood, M.K.; Soni, Y.; Overturf, B.W.; Wiede, W.; Clark, S. et al.
Partner: UNT Libraries Government Documents Department

MOD silver metallization for photovoltaics. Quarterly technical report, December 1, 1983-February 29, 1984. [Metallo-organic decomposition]

Description: It was determined that pyrolysis products can produce dark surface films on MOD silver conductors. Improving the purity of all ink ingredients helped this problem. It was established that the existence and nature of the surface film is influenced by the rate of air flow during firing and by the heating rate in the 70 to 225/sup 0/C range, but these processing parameters have not as yet been optimized. Low temperature solvent removal was determined to be of prime importance in obtaining good adhesion between the MOD films and the substrate. For inks developed to date, 15 to 30 minutes at 60 to 70/sup 0/C was required. It was also determined that the adhesion is influenced by the air flow rate during firing, the heating rate in the 100 to 250/sup 0/C range, and the maximum firing temperature. Results during the first 3 months of effort on this project have demonstrated that it is essential to use generic compounds, and that the compounds must be prepared from high purity raw materials. It was also established that the quality and properties of the MOD silver films are intimately dependent on the time-temperature processing. All of the results obtained to date still indicate that MOD silver shows great promise for low temperature metallization of photovoltaic cells.
Date: March 20, 1984
Creator: Vest, G.M. & Vest, R.W.
Partner: UNT Libraries Government Documents Department