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Multi-Scale Assessment of Prediction Uncertainty in Coupled Reactive Transport Models Conducted at the Florida State University

Description: This report summarizes the research activities in the Florida State University for quantifying parametric and model uncertainty in groundwater reactive transport modeling. Mathematical and computational research was conducted to investigate the following five questions: (1) How does uncertainty behave and affect groundwater reactive transport models? (2) What cause the uncertainty in groundwater reactive transport modeling? (3) How to quantify parametric uncertainty of groundwater reactive transport modeling? (4) How to quantify model uncertainty of groundwater reactive transport modeling? and (5) How to reduce predictive uncertainty by collecting data of maximum value of information or data-worth? The questions were addressed using Interdisciplinary methods, including computational statistics, Bayesian uncertainty analysis, and groundwater modeling. Both synthetic and real-world data were used to evaluate and demonstrate the developed methods. The research results revealed special challenges to uncertainty quantification for groundwater reactive transport models. For example, competitive reactions and substitution effects of reactions also cause parametric uncertainty. Model uncertainty is more important than parametric uncertainty, and model averaging methods are a vital tool to improve model predictions. Bayesian methods are more accurate than regression methods for uncertainty quantification. However, when Bayesian uncertainty analysis is computationally impractical, uncertainty analysis using regression methods still provides insights into uncertainty analysis. The research results of this study are useful to science-informed decision-making and uncertainty reduction by collecting data of more value of information.
Date: November 9, 2013
Creator: Ye, Ming
Partner: UNT Libraries Government Documents Department

Final Report for DOE Grant DE-FG02-07ER64470 [“Incorporation of the HYbrid Coordinate Ocean Model (HYCOM) into the Community Climate System Model (CCSM): Evaluation and Climate Applications”]

Description: The primary goal of the project entitled “Incorporation of the HYbrid Coordinate Ocean Model (HYCOM) into the Community Climate System Model (CCSM): Evaluation and Climate Applications” was to systematically investigate the performance of the HYbrid Coordinate Ocean Model (HYCOM) as an alternative oceanic component of the NCAR’s Community Climate System Model (CCSM). We have configured two versions of the fully coupled CCSM3/HYCOM: one with a medium resolution (T42) Community Atmospheric Model (CAM) and the other with higher resolution (T85). We have performed a comprehensive analysis of the 400-year fully coupled CCSM3/HYCOM simulations and compared the results with those from CCSM3/POP and with climatological observations, and also we have performed tuning of critical model parameters, including Smagorinsky viscosity, isopycnal diffusivity, and background vertical diffusivity. The analysis shows that most oceanic features are well represented in the CCSM3/HYCOM. The coupled CCSM3/HYCOM (T42) has been integrated for 400 years, and the results have been archived and transferred to the High Performance Computer in the Florida State Univesity. In the last year, we have made comprehensive diagnostics of the long-term simulations by the comparison with the original CCSM3/POP simulation and with the observations. To gain some understanding of the model biases, the mean climate and modes of climate variability of the two models are compared with observations. The examination includes the Northern and Southern Annular Modes (NAM and SAM), the Pacific-North-American (PNA) pattern, the Atlantic Multidecadal Oscillation (AMO), and the main Southern Ocean SST mode. We also compared the performance of ENSO simulation in the coupled models. This report summarizes the main findings from the comparison of long-term CCSM3/HYCOM and CCSM3/POP simulations.
Date: March 18, 2013
Creator: Chassignet, Eric P
Partner: UNT Libraries Government Documents Department

An Integrated Assessment of Geochemical and Community Structure Determinants of Metal Reduction Rates in Subsurface Sediments

Description: Summary of Results to Date: Our current research represents a joint effort between Oak Ridge National Laboratory (ORNL), Florida State University (FSU), and the University of Tennessee. ORNL will serve as the lead institution with Dr. A.V. Palumbo responsible for project coordination, integration, and deliverables. This project was initiated in November, 2004, in the Integrative Studies Element of the NABIR program. The overall goal of our project is to provide an improved understanding of the relationships between microbial community structure, geochemistry, and metal reduction rates.
Date: August 11, 2005
Creator: Kostka, Joel E.
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration

Description: The objective of this research project is to develop the necessary thermodynamic data, including aqueous phase stability constants and Pitzer ion-interaction parameters, to predict the changes in the aqueous phase chemistry that occur when high ionic strength, highly basic tank wastes enter the vadose zone.
Date: December 1, 2004
Creator: Choppin, Gregory R.
Partner: UNT Libraries Government Documents Department

Impacts of Mineralogy and Competing Microbial Respiration Pathways on the Fate of Uranium in Contaminated Groundwater

Description: This is a field-oriented project designed to elucidate the microbiological and geochemical factors controlling U(VI) reduction/immobilization in subsurface environments at the NABIR FRC. Efforts focused on acidic sediments, (1) to characterize the dominant minerals likely to limit U speciation, (2) to directly quantify microbial respiration processes controlling U subsurface chemistry, and (3) to identify and enumerate the responsible organisms. Results indicate that the activities and growth of bacteria are limited in this acidic subsurface. The relevant geochemical parameters have now been characterized, and respiration rates quantified.
Date: June 1, 2003
Creator: Kostka, Joel E.
Partner: UNT Libraries Government Documents Department

The DOE Subsurface Microbial Culture Collection (SMCC)

Description: The primary activities associated with maintenance of the Subsurface Microbial Culture Collection (SMCC) were designed to ensure that the collection served as a valuable resource to DOE-funded and other scientists, especially DOE-funded scientists associated with the NABIR Program. These activities were carried out throughout the period covered by this report and in-cluded: (1) assistance in the selection of cultures for research, (2) distribution of cultures and/or data on request, (3) incorporation of newly isolated microbial strains, (4) preservation of newly isolated strains, (5) partial characterization of newly isolated strains, (6) development and main-tenance of representative subsets of cultures, (6) screening of SMCC strains for specific charac-teristics, (7) phylogenetic characterization of SMCC strains, (8) development and maintenance of a SMCC website, (9) maintenance of the SMCC databases, (10) archiving of SMCC records, and (11) quality assurance/quality control (QA/QC) activities. We describe in the Final Technical Report our accomplishments related to these activities during the period covered by this report.
Date: May 23, 2006
Creator: Balkwill, David L.
Partner: UNT Libraries Government Documents Department

Random Number Generation for Petascale Quantum Monte Carlo

Description: The quality of random number generators can affect the results of Monte Carlo computations, especially when a large number of random numbers are consumed. Furthermore, correlations present between different random number streams in a parallel computation can further affect the results. The SPRNG software, which the author had developed earlier, has pseudo-random number generators (PRNGs) capable of producing large numbers of streams with large periods. However, they had been empirically tested on only thousand streams earlier. In the work summarized here, we tested the SPRNG generators with over a hundred thousand streams, involving over 10^14 random numbers per test, on some tests. We also tested the popular Mersenne Twister. We believe that these are the largest tests of PRNGs, both in terms of the numbers of streams tested and the number of random numbers tested. We observed defects in some of these generators, including the Mersenne Twister, while a few generators appeared to perform well. We also corrected an error in the implementation of one of the SPRNG generators.
Date: March 16, 2010
Creator: Srinivasan, Ashok
Partner: UNT Libraries Government Documents Department

Final report to the DOE for the period 8/1/96 to 5/31/00 by the SCRI Theoretical High Energy Group

Description: This is the final report on grant DE-FG05-96ER40979 from the US Department of Energy supporting the research of the Theoretical High Energy Physics group at the Supercomputer Computations Research Institute (SCRI) at Florida State University. The research primarily involved lattice field theory simulations such as Quantum Chromodynamics (QCD). Although QCD is generally accepted as the theory which describes the strong interactions responsible for nuclear binding, convincing computations of the properties of the elementary particles from first principles are still elusive. The problem lies in the fact that for data at the low energies involved ({approx} 1 GeV), the coupling constant in QCD is large, preventing application of the physicist's usual tool, perturbation theory. Non-perturbative computations are necessary and they appear possible only via large scale numerical simulations. Especially simulations of full QCD, including the effect of light dynamical quarks, are extremely CPU time consuming. The scientists in SCRI's lattice gauge theory group have been in the forefront of such numerical simulations since the inception of SCRI in 1985. A major research topic was the study of improved lattice actions, designed to diminish finite lattice spacing effects and thus accelerate the approach to the continuum limit. Most of this work was carried out in the quenched approximation. Very encouraging results were obtained. In the second half of the funding period, a major focus of the group has been the use of a new lattice fermion representation, Overlap fermions, that has achieved the much desired goal of preserving the chiral symmetry properties of the continuum theory at finite lattice spacing. After developing an algorithm for the numerical simulations of overlap fermions, the SCRI group has completed the first studies of the relation between chiral symmetry breaking and topology using this new formalism.
Date: November 29, 2000
Creator: Heller, Urs
Partner: UNT Libraries Government Documents Department

New theoretical approach for elucidating the solution structure of peptides from NMR data. Final report on DOE Grant DE-FG02-97ER62490

Description: In this project we have developed a new computational methodology, based on statistical mechanics considerations, for analyzing experimental structural data of flexible peptides and segments of proteins (typically surface loops and chain ends). This methodology is applicable to multidimensional nuclear magnetic resonance (NMR), X-ray crystallography, and potentially fluorescence spectroscopy and other techniques. NMR is the only physical technique that can generate three dimensional structures of biomolecules in solution. It is well established for globular proteins which reside in a single microstate, i.e. a limited region of conformational space around the native structure. Nuclear Overhauser Enhancement (NOE) contacts indicative of structure can also be obtained from more flexible systems (e.g., peptides, carbohydrates, and DNA segments), which are expected to populate significantly several microstates in thermodynamic equilibrium. However, in this case the NOEs might become weighted averages of contributions of the individual microstates, which makes the interpretation of the data difficult, because of the need to identify the most stable microstates arid calculate their relative populations. Development of reliable analysis techniques in this field is a challenge.
Date: May 1, 2002
Creator: Meirovitch, Hagai
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration

Description: The objective of this research project is to develop the necessary thermodynamic data, including aqueous phase stability constants and Pitzer ion-interaction parameters, to predict the changes in the aqueous phase chemistry that occur when high ionic strength, highly basic tank wastes enter the vadose zone.
Date: June 1, 2003
Creator: Choppin, Gregory R.
Partner: UNT Libraries Government Documents Department

Vadose zone microbial community structure and activity in metal/radionuclide contaminated sediments. Final technical report

Description: This final technical report describes the research carried out during the final two months of the no-cost extension ending 11/14/01. The primary goals of the project were (1) to determine the potential for transformation of Cr(VI) (oxidized, mobile) to Cr(III) (reduced, immobile) under unsaturated conditions as a function of different levels and combinations of (a) chromium, (b) nitrate (co-disposed with Cr), and (c) molasses (inexpensive bioremediation substrate), and (2) to determine population structure and activity in experimental treatments by characterization of the microbial community by signature biomarker analysis and by RT-PCR and terminal restriction fragment length polymorphism (T-RFLP) and 16S ribosomal RNA genes. It was determined early in the one-year no-cost extension period that the T-RFLP approach was problematic in regard to providing information on the identities of microorganisms in the samples examined. As a result, it could not provide the detailed information on microbial community structure that was needed to assess the effects of treatments with chromium, nitrate, and/or molasses. Therefore, we decided to obtain the desired information by amplifying (using TR-PCR, with the same primers used for T-RFLP) and cloning 16S rRNA gene sequences from the same RNA extracts that were used for T-RFLP analysis. We also decided to use a restriction enzyme digest procedure (fingerprinting procedure) to place the clones into types. The primary focus of the research carried out during this report period was twofold: (a) to complete the sequencing of the clones, and (b) to analyze the clone sequences phylogenetically in order to determine the relatedness of the bacteria detected in the samples to each other and to previously described genera and species.
Date: August 17, 2002
Creator: Balkwill, David L.
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration

Description: The objective of this research project is to develop the necessary thermodynamic data, including aqueous phase stability constants and Pitzer ion-interaction parameters, to predict the changes in aqueous phase chemistry that occur when high ionic strength , highly basic tank wastes enter the vadose zone.
Date: June 1, 2003
Creator: Choppin, Gregory R.
Partner: UNT Libraries Government Documents Department

Investigating In Situ Bioremediation Approaches for Sustained Uranium Immobilization Independent of Nitrate Reduction

Description: The daunting prospect of complete nitrate removal at DOE sites, such as the ERSP Oak Ridge Field Research Center (FRC), provides strong incentive to explore bioremediation strategies that will allow for uranium bioreduction and long-term stabilization in the presence of nitrate. The cost and effort required for complete nitrate removal from the FRC and similar DOE-contaminated sites may prove to be unworkable. For example, field tests of uranium bioreduction at the FRC have shown that nitrate levels rebound quickly and completely after cessation of active biostimulation.
Date: June 1, 2006
Creator: Phelps, Tommy & Balkwill, David
Partner: UNT Libraries Government Documents Department

Final Technical Report, Grant DE-FG02-91ER45443: Heavy fermions and other highly correlated electron systems

Description: Properties of highly correlated electrons, such as heavy fermion compounds, metal-insulator transitions, one-dimensional conductors and systems of restricted dimensionality are studied theoretically. The main focus is on Kondo insulators and impurity bands due to Kondo holes, the low-temperature magnetoresistivity of heavy fermion alloys, the n-channel Kondo problem, mesoscopic systems and one-dimensional conductors.
Date: October 12, 1998
Creator: Schlottmann, P.
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica and Uranium Species to High Concentration.

Description: Highly basic tank wastes contain several important radionuclides, including 90Sr, 99Tc, and 60Co, as well as actinide elements (i.e., isotopes of U, Pu, and Am). These highly basic tank wastes are known to have leaked into the vadose zone at the Hanford Site. In particular, wastes from the bismuth phosphate process contained very high concentrations of U as well as carbonate, phosphate, nitrate, and other components (AEC 1951) and these solutions have leaked into the subsurface at the Hanford site. The tanks containing the bismuth phosphate wastes were frequently saturated with respect to the solid phases of these components [e.g., NaUO2PO4(c) and Na4UO2(CO3)3(c)]. These solids were referred to as ''hard sludge'' (Na4UO2(CO3)3(c)) and ?soft sludge? [NaUO2PO4(c)] because of their different crystal forms. The preliminary studies of the solubility of these solids in tank wastes (AEC 1951) indicate that aqueous U carbonate complexes dominate the solution chemistry of uranium even when the equilibrium solid was NaUO2PO4. Thus there was a need to develop an accurate thermodynamic model for the solubility of potentially important U(VI) phosphate and carbonate phases as well as to develop a model for the uranium carbonate complexes valid to high ionic strength. In this project we are examining the solubility of these important solid phases as well as the aqueous thermodynamics of U(VI) species under strongly basic conditions. Also included is a description of our efforts to include these thermodynamic models in the reactive transport and residual leaching models being used at the Hanford site and elsewhere.
Date: June 1, 2005
Creator: Felmy, Andrew R. & Choppin, Gregory R.
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Anionic Silica Species to High Concentration: Effects on Neutralization of Leaked Tank Wastes and Migration of Radionuclides in the Subsurface

Description: Highly basic tank wastes contain several important radionuclides, including {sup 90}Sr, {sup 99}Tc, and {sup 60}Co, as well as actinide elements (i.e., isotopes of U, Pu, and Am). These highly basic tank wastes are known to have leaked into the vadose zone at the Hanford Site. Upon entering the sediments in the vadose zone, the highly basic solutions dissolve large concentrations of silica from the silica and aluminosilicate minerals present in the subsurface. These dissolution reactions alter the chemical composition of the leaking solutions, transforming them from a highly basic (as high as 2M NaOH) solution into a pore solution with a very high concentration of dissolved silica and a significantly reduced pH. This moderately basic (pH 9 to 11), high-silica solution has the potential to complex radionuclides and move through the subsurface. Such strong radionuclide complexation is a currently unconsidered transport vector that has the potential to expedite radionuclide transport through the vadose zone. These strong complexation effects have the ability to significantly alter current conceptual models of contaminant migration beneath leaking tanks. In this project, we are determining the aqueous thermodynamics and speciation of dissolved silica and silica-radionuclide complexes to high silica concentration using a combination of (1) studies of chemical species structure and composition [via nuclear magnetic resonance (NMR) and, where applicable, laser-induced fluorescence spectroscopy and x-ray absorption spectroscopy] (2) molecular simulations to help identify key species structures and assist in interpreting experimental measurements (3) fundamental physical chemistry measurements, including solubility, electromotive force, and isopiestic measurements, to obtain the necessary thermodynamic data for predicting contaminant complexation and waste neutralization reactions. The radioactive elements we are studying include Sr, Co, Cs, Am(III), and U(VI).
Date: June 1, 2002
Creator: Felmy, Andrew R.; Choppin, Gregory & Dixon, David A.
Partner: UNT Libraries Government Documents Department

The Aqueous Thermodynamics and Complexation Reactions of Radionuclides to High Ionic Strength: Applications in Subsurface Science and High-Level Waste Processing

Description: This presentation was given at the DOE Office of Science-Environmental Management Science Program (EMSP) High-Level Waste Workshop held on January 19-20, 2005 at the Savannah River Site.
Date: January 20, 2005
Creator: Felmy, Andrew; Wang, Zheming; Cho, Herman; Hess, Nancy; Choppin, Gregory & Dixon, David
Partner: UNT Libraries Government Documents Department

Development of Fundamental Data on Chemical Speciation and Solubility for Strontium and Americium in High-Level Waste: Predictive Modeling of Phase Partitioning During Tank Processing

Description: In this project, Pacific Northwest National Laboratory (PNNL) and Florida State University (FSU) are investigating the speciation of Sr and Am/Cm in the presence of selected organic chelating agents over ranges of hydroxide, carbonate, ionic strength, and competing metal ion concentrations present in high-level waste (HLW) stored in tanks at Hanford and other U.S. Department of Energy (DOE) sites. The chelating agents that are being studied are EDTA (ethylenediaminetetraacetic acid), HEDTA (N-(2-hydroxyethyl)ethylenediaminetriacetic acid), NTA (nitrilotriacetic acid), IDA (iminodiacetic acid), citrate, and oxalate. The project comprises integrated research tasks that approach the problem of chemical speciation using macroscopic thermodynamic measurements of metal-ligand competition reactions, molecular modeling studies to identify structures or complexes of unusual stability, and mass spectrometry measurements of complex charge/mass ratio that can be applied to mixed metalchelate systems. This fundamental information then is used to develop thermodynamic models designed to predict changes in chemical speciation and solubility resulting from various tank processing conditions. In this way we can develop new approaches that address fundamental problems in aqueous speciation and, at the same time, provide useful and practical information needed for tank waste processing. Current strategies for reducing the total volume of radioactive tank waste requiring disposal at Hanford and other DOE sites call for the development of methods that can be used to selectively dissolve and remove non-radioactive elements, such as Al, P, and Cr, while retaining or precipitating the radioactive elements, including Sr and the actinide elements, in the tank sludge. This partitioning between solids and precipitates is fundamentally dependent on the chemical speciation of the elements present in the tank processing solutions. Of particular importance is separation of the radioactive and hazardous actinide elements and fission products from the sludge and supernatants, particularly from supernatants containing high concentrations of strong chelating agents that can act to ...
Date: June 1, 2002
Creator: Felmy, Andrew R.; Choppin, Gregory & Dixon, David A.
Partner: UNT Libraries Government Documents Department

On the mass and salt budgets for a region of the continental shelf in the southern Mid-Atlantic Bight

Description: Two field studies were conducted across and along the continental shelf, one from February to May 1996 (deployment 1) and the other from July to October 1996 (deployment 2), in part to determine the mass and salt budgets of shelf water from south of Cape Henry to north of Cape Hatteras, the southernmost portion of the Mid-Atlantic Bight. The temporal means of current meter records indicated that most of the water enters the region across its northern boundary near the shelf break as part of a southward, alongshore current and exits the southeast corner as a southeastward flowing current. Estimates of the volume transports indicated that not all the transport across the northern boundary was accounted for by transport across the southern boundary, and that the remainder occurred as a broad, diffusive flow across the eastern boundary at the shelf break. Time series of volume transport across northern and southern boundaries were very similar and associated with variations in the alongshore wind stress and sea level, indicative of a geostrophic balance. Examination of the individual current meter records indicated these fluctuations were very barotropic even during deployment 2, which included the stratified summer season. Time series of the volume transport across the eastern boundary at the shelf break strongly mirrored the volume transport across the northern boundary minus that across the southern boundary, suggesting that the inferred eastern boundary transport was real and accommodated whatever the southern boundary could not. The turbulent salt flux across each boundary contributes very little to the net respective mass fluxes because the salt fluxes are almost governed by current velocity fields. The instantaneous and mean salt fluxes across each boundary were very well approximated by the instantaneous and mean volume transports across the boundary times the deployment average salinity across that boundary, respectively. The ...
Date: December 1, 2001
Creator: Kim, Yoo Yin; Weatherly, Georges L. & Pietrafesa, Leonard J.
Partner: UNT Libraries Government Documents Department