Sample records for reactive transport models

  1. A smoothed particle hydrodynamics model for reactive transport...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A smoothed particle hydrodynamics model for reactive transport and mineral precipitation in porous and fractured porous media. A smoothed particle hydrodynamics model for reactive...

  2. Reactive Transport Modeling and Geophysical Monitoring of Bioclogging at Reservoir Scale

    E-Print Network [OSTI]

    Hubbard, Susan

    Reactive Transport Modeling and Geophysical Monitoring of Bioclogging at Reservoir Scale Vikranth scale using a combination of reactive transport modeling and geophysical imaging tools (EM & seismic Sacramento basin, California; the model well (Citizen Green #1) was characterized using sonic, electrical

  3. Toward Optimized Bioclogging and Biocementation Through Combining Advanced Geophysical Monitoring and Reactive Transport Modeling

    E-Print Network [OSTI]

    Hubbard, Susan

    and electrical techniques); (ii) developing and using a reactive transport simulator capable of predicting and Reactive Transport Modeling Approaches Christopher G Hubbard1 , Susan S. Hubbard1 , Yuxin Wu1 , Vikranth heterogeneities at the field scale. Optimization of these strategies requires advances in mechanistic reactive

  4. Field, Laboratory, and Modeling Study of Reactive Transport of

    E-Print Network [OSTI]

    University of New York, Flushing, New York 11367, Department of Marine Chemistry and Geochemistry, Woods Hole Bay, MA, shed light on coupled control of chemistry and hydrology on reactive transport), phosphate (5), and oxyanions of molybdenum (6) and uranium (7, 8) in aquifers. In addition

  5. Multicomponent reactive transport modeling of uranium bioremediation field experiments

    SciTech Connect (OSTI)

    Fang, Yilin; Yabusaki, Steven B.; Morrison, Stan J.; Amonette, James E.; Long, Philip E.

    2009-10-15T23:59:59.000Z

    Biostimulation field experiments with acetate amendment are being performed at a former uranium mill tailings site in Rifle, Colorado, to investigate subsurface processes controlling in situ bioremediation of uranium-contaminated groundwater. An important part of the research is identifying and quantifying field-scale models of the principal terminal electron-accepting processes (TEAPs) during biostimulation and the consequent biogeochemical impacts to the subsurface receiving environment. Integrating abiotic chemistry with the microbially mediated TEAPs in the reaction network brings into play geochemical observations (e.g., pH, alkalinity, redox potential, major ions, and secondary minerals) that the reactive transport model must recognize. These additional constraints provide for a more systematic and mechanistic interpretation of the field behaviors during biostimulation. The reaction network specification developed for the 2002 biostimulation field experiment was successfully applied without additional calibration to the 2003 and 2007 field experiments. The robustness of the model specification is significant in that 1) the 2003 biostimulation field experiment was performed with 3 times higher acetate concentrations than the previous biostimulation in the same field plot (i.e., the 2002 experiment), and 2) the 2007 field experiment was performed in a new unperturbed plot on the same site. The biogeochemical reactive transport simulations accounted for four TEAPs, two distinct functional microbial populations, two pools of bioavailable Fe(III) minerals (iron oxides and phyllosilicate iron), uranium aqueous and surface complexation, mineral precipitation, and dissolution. The conceptual model for bioavailable iron reflects recent laboratory studies with sediments from the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site that demonstrated that the bulk (~90%) of Fe(III) bioreduction is associated with the phyllosilicates rather than the iron oxides. The uranium reaction network includes a U(VI) surface complexation model based on laboratory studies with Old Rifle UMTRA sediments and aqueous complexation reactions that include ternary complexes (e.g., calcium-uranyl-carbonate). The bioreduced U(IV), Fe(II), and sulfide components produced during the experiments are strongly associated with the solid phases and may play an important role in long-term uranium immobilization.

  6. Reactive Transport Modeling of Natural Attenuation in Stormwater Bioretention Cells and Under Land Application of Wastewater 

    E-Print Network [OSTI]

    Zhang, Jingqiu

    2014-04-29T23:59:59.000Z

    hydrocarbon, nutrient, metals, and solids. Vegetation also plays an important role in reducing water volume, and removing nutrients and solutes from the contaminated soil. We used a reactive transport model MIN3P-THM to simulate the natural attenuation...

  7. Pore scale modeling of reactive transport involved in geologic CO2 sequestration

    SciTech Connect (OSTI)

    Kang, Qinjin [Los Alamos National Laboratory; Lichtner, Peter C [Los Alamos National Laboratory; Viswanathan, Hari S [Los Alamos National Laboratory; Abdel-fattah, Amr I [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    We apply a multi-component reactive transport lattice Boltzmann model developed in previolls studies to modeling the injection of a C02 saturated brine into various porous media structures at temperature T=25 and 80 C. The porous media are originally consisted of calcite. A chemical system consisting of Na+, Ca2+, Mg2+, H+, CO2(aq), and CI-is considered. The fluid flow, advection and diHusion of aqueous species, homogeneous reactions occurring in the bulk fluid, as weB as the dissolution of calcite and precipitation of dolomite are simulated at the pore scale. The effects of porous media structure on reactive transport are investigated. The results are compared with continuum scale modeling and the agreement and discrepancy are discussed. This work may shed some light on the fundamental physics occurring at the pore scale for reactive transport involved in geologic C02 sequestration.

  8. Benchmarking a Visual-Basic based multi-component one-dimensional reactive transport modeling tool

    E-Print Network [OSTI]

    Clement, Prabhakar

    Benchmarking a Visual-Basic based multi-component one-dimensional reactive transport modeling tool of a comprehensive numerical modeling tool, RT1D, which can be used for simulating biochemical and geochemical, and it does not require any additional software tools. The code can be easily adapted by others for simulating

  9. A model for reactive porous transport during re-wetting of hardened concrete

    E-Print Network [OSTI]

    Stockie, John

    A model for reactive porous transport during re-wetting of hardened concrete Michael Chapwanya residing in the porous concrete matrix. The main hypothesis in this model is that the reaction product hydration; Porous media; Reaction-diffusion equations; Vari- able porosity. 1. Introduction Concrete

  10. REVIEW AND ANALYSIS Research Activities at U.S. Government Agencies in Subsurface Reactive Transport Modeling

    E-Print Network [OSTI]

    All T. Cygan; Caroline T. Stevens; Robert W. Puls; Steven B. Yabusaki; Robert D; David R. Turner

    Subsurface reactive transport modeling may be defi ned as the use of mathematical models to simulate the fate and transport of dissolved species and particulates in groundwater as these species are transported through porous media and react with each other, with mineral surfaces, and with microbes associated with the porous media matrix. This type of modeling has evolved over the last 30 yr from a specialized research topic involving a dozen or so practitioners (with often large stacks of computer punch cards) to a common offi ce tool found today on the personal computer (and occasional supercomputer) of many environmental chemists, geochemists, and soil scientists. The devel-

  11. Application of reactive transport modelling to growth and transport of microorganisms in the capillary fringe

    E-Print Network [OSTI]

    Hron, Pavel; Bastian, Peter; Gallert, Claudia; Winter, Josef; Ippisch, Olaf

    2014-01-01T23:59:59.000Z

    A multicomponent multiphase reactive transport simulator has been developed to facilitate the investigation of a large variety of phenomena in porous media including component transport, diffusion, microbiological growth and decay, cell attachment and detachment and phase exchange. The coupled problem is solved using operator splitting. This approach allows a flexible adaptation of the solution strategy to the concrete problem. Moreover, the individual submodels were optimised to be able to describe behaviour of Escherichia coli (HB101 K12 pGLO) in the capillary fringe in the presence or absence of dissolved organic carbon and oxygen under steady-state and flow conditions. Steady-state and flow through experiments in a Hele-Shaw cell, filled with quartz sand, were conducted to study eutrophic bacterial growth and transport in both saturated and unsaturated porous media. As E. coli cells can form the green fluorescent protein (GFP), the cell densities, calculated by evaluation of measured fluorescence intensit...

  12. Application of a data assimilation method via an ensemble Kalman filter to reactive urea hydrolysis transport modeling

    SciTech Connect (OSTI)

    Juxiu Tong; Bill X. Hu; Hai Huang; Luanjin Guo; Jinzhong Yang

    2014-03-01T23:59:59.000Z

    With growing importance of water resources in the world, remediations of anthropogenic contaminations due to reactive solute transport become even more important. A good understanding of reactive rate parameters such as kinetic parameters is the key to accurately predicting reactive solute transport processes and designing corresponding remediation schemes. For modeling reactive solute transport, it is very difficult to estimate chemical reaction rate parameters due to complex processes of chemical reactions and limited available data. To find a method to get the reactive rate parameters for the reactive urea hydrolysis transport modeling and obtain more accurate prediction for the chemical concentrations, we developed a data assimilation method based on an ensemble Kalman filter (EnKF) method to calibrate reactive rate parameters for modeling urea hydrolysis transport in a synthetic one-dimensional column at laboratory scale and to update modeling prediction. We applied a constrained EnKF method to pose constraints to the updated reactive rate parameters and the predicted solute concentrations based on their physical meanings after the data assimilation calibration. From the study results we concluded that we could efficiently improve the chemical reactive rate parameters with the data assimilation method via the EnKF, and at the same time we could improve solute concentration prediction. The more data we assimilated, the more accurate the reactive rate parameters and concentration prediction. The filter divergence problem was also solved in this study.

  13. Modeling non-isothermal multiphase multi-species reactive chemical transport in geologic media

    SciTech Connect (OSTI)

    Tianfu Xu; Gerard, F.; Pruess, K.; Brimhall, G.

    1997-07-01T23:59:59.000Z

    The assessment of mineral deposits, the analysis of hydrothermal convection systems, the performance of radioactive, urban and industrial waste disposal, the study of groundwater pollution, and the understanding of natural groundwater quality patterns all require modeling tools that can consider both the transport of dissolved species as well as their interactions with solid (or other) phases in geologic media and engineered barriers. Here, a general multi-species reactive transport formulation has been developed, which is applicable to homogeneous and/or heterogeneous reactions that can proceed either subject to local equilibrium conditions or kinetic rates under non-isothermal multiphase flow conditions. Two numerical solution methods, the direct substitution approach (DSA) and sequential iteration approach (SIA) for solving the coupled complex subsurface thermo-physical-chemical processes, are described. An efficient sequential iteration approach, which solves transport of solutes and chemical reactions sequentially and iteratively, is proposed for the current reactive chemical transport computer code development. The coupled flow (water, vapor, air and heat) and solute transport equations are also solved sequentially. The existing multiphase flow code TOUGH2 and geochemical code EQ3/6 are used to implement this SIA. The flow chart of the coupled code TOUGH2-EQ3/6, required modifications of the existing codes and additional subroutines needed are presented.

  14. Multiphase flow and multicomponent reactive transport model of the ventilation experiment in Opalinus clay

    SciTech Connect (OSTI)

    Zheng, L.; Samper, J.; Montenegro, L.; Major, J.C.

    2008-10-15T23:59:59.000Z

    During the construction and operational phases of a high-level radioactive waste (HLW) repository constructed in a clay formation, ventilation of underground drifts will cause desaturation and oxidation of the rock. The Ventilation Experiment (VE) was performed in a 1.3 m diameter unlined horizontal microtunnel on Opalinus clay at Mont Terri underground research laboratory in Switzerland to evaluate the impact of desaturation on rock properties. A multiphase flow and reactive transport model of VE is presented here. The model accounts for liquid, vapor and air flow, evaporation/condensation and multicomponent reactive solute transport with kinetic dissolution of pyrite and siderite and local-equilibrium dissolution/precipitation of calcite, ferrihydrite, dolomite, gypsum and quartz. Model results reproduce measured vapor flow, liquid pressure and hydrochemical data and capture the trends of measured relative humidities, although such data are slightly overestimated near the rock interface due to uncertainties in the turbulence factor. Rock desaturation allows oxygen to diffuse into the rock and triggers pyrite oxidation, dissolution of calcite and siderite, precipitation of ferrihydrite, dolomite and gypsum and cation exchange. pH in the unsaturated rock varies from 7.8 to 8 and is buffered by calcite. Computed changes in the porosity and the permeability of Opalinus clay in the unsaturated zone caused by oxidation and mineral dissolution/precipitation are smaller than 5%. Therefore, rock properties are not expected to be affected significantly by ventilation of underground drifts during construction and operational phases of a HLW repository in clay.

  15. Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation

    SciTech Connect (OSTI)

    Wu, Y.; Ajo-Franklin, J.B.; Spycher, N.; Hubbard, S.S.; Zhang, G.; Williams, K.H.; Taylor, J.; Fujita, Y.; Smith, R.

    2011-07-15T23:59:59.000Z

    Ureolytically-driven calcium carbonate precipitation is the basis for a promising in-situ remediation method for sequestration of divalent radionuclide and trace metal ions. It has also been proposed for use in geotechnical engineering for soil strengthening applications. Monitoring the occurrence, spatial distribution, and temporal evolution of calcium carbonate precipitation in the subsurface is critical for evaluating the performance of this technology and for developing the predictive models needed for engineering application. In this study, we conducted laboratory column experiments using natural sediment and groundwater to evaluate the utility of geophysical (complex resistivity and seismic) sensing methods, dynamic synchrotron x-ray computed tomography (micro-CT), and reactive transport modeling for tracking ureolytically-driven calcium carbonate precipitation processes under site relevant conditions. Reactive transport modeling with TOUGHREACT successfully simulated the changes of the major chemical components during urea hydrolysis. Even at the relatively low level of urea hydrolysis observed in the experiments, the simulations predicted an enhanced calcium carbonate precipitation rate that was 3-4 times greater than the baseline level. Reactive transport modeling results, geophysical monitoring data and micro-CT imaging correlated well with reaction processes validated by geochemical data. In particular, increases in ionic strength of the pore fluid during urea hydrolysis predicted by geochemical modeling were successfully captured by electrical conductivity measurements and confirmed by geochemical data. The low level of urea hydrolysis and calcium carbonate precipitation suggested by the model and geochemical data was corroborated by minor changes in seismic P-wave velocity measurements and micro-CT imaging; the latter provided direct evidence of sparsely distributed calcium carbonate precipitation. Ion exchange processes promoted through NH{sub 4}{sup +} production during urea hydrolysis were incorporated in the model and captured critical changes in the major metal species. The electrical phase increases were potentially due to ion exchange processes that modified charge structure at mineral/water interfaces. Our study revealed the potential of geophysical monitoring for geochemical changes during urea hydrolysis and the advantages of combining multiple approaches to understand complex biogeochemical processes in the subsurface.

  16. Modeling hydrology and reactive transport in roads: The effect of cracks, the edge, and contaminant properties

    SciTech Connect (OSTI)

    Apul, Defne S. [Department of Civil Engineering, University of Toledo, 2801 W. Bancroft St., Mail Stop 307, Toledo, OH 43606 (United States)], E-mail: Defne.apul@utoledo.edu; Gardner, Kevin H. [Environmental Research Group, Department of Civil Engineering, 35 Colovos Road, Durham, NH 03824 (United States)], E-mail: Kevin.gardner@unh.edu; Eighmy, T. Taylor [Environmental Research Group, Department of Civil Engineering, 35 Colovos Road, Durham, NH 03824 (United States)], E-mail: Taylor.eighmy@unh.edu

    2007-07-01T23:59:59.000Z

    The goal of this research was to provide a tool for regulators to evaluate the groundwater contamination from the use of virgin and secondary materials in road construction. A finite element model, HYDRUS2D, was used to evaluate generic scenarios for secondary material use in base layers. Use of generic model results for particular applications was demonstrated through a steel slag example. The hydrology and reactive transport of contaminants were modeled in a two-dimensional cross section of a road. Model simulations showed that in an intact pavement, lateral velocities from the edge towards the centerline may transport contaminants in the base layer. The dominant transport mechanisms are advection closer to the edge and diffusion closer to the centerline. A shoulder joint in the pavement allows 0.03 to 0.45 m{sup 3}/day of infiltration per meter of joint length as a function of the base and subgrade hydrology and the rain intensity. Scenario simulations showed that salts in the base layer of pavements are depleted by 99% in the first 20 years, whereas the metals may not reach the groundwater in 20 years at any significant concentrations if the pavement is built on adsorbing soils.

  17. Direct coupling of a genome-scale microbial in silico model and a groundwater reactive transport model

    SciTech Connect (OSTI)

    Fang, Yilin; Scheibe, Timothy D.; Mahadevan, Radhakrishnan; Garg, Srinath; Long, Philip E.; Lovley, Derek R.

    2011-02-28T23:59:59.000Z

    The activity of microorganisms often plays an important role in dynamic natural attenuation or engineered bioremediation of subsurface contaminants, such as chlorinated solvents, metals, and radionuclides. To evaluate and/or design bioremediated systems, quantitative reactive transport models are needed. State-of-the-art reactive transport models often ignore the microbial effects or simulate the microbial effects with static growth yield and constant reaction rate parameters over simulated conditions, while in reality microorganisms can dynamically modify their functionality (such as utilization of alternative respiratory pathways) in response to spatial and temporal variations in environmental conditions. Constraint-based genome-scale microbial in silico models, using genomic data and multiple-pathway reaction networks, have been shown to be able to simulate transient metabolism of some well studied microorganisms and identify growth rate, substrate uptake rates, and byproduct rates under different growth conditions. These rates can be identified and used to replace specific microbially-mediated reaction rates in a reactive transport model using local geochemical conditions as constraints. We previously demonstrated the potential utility of integrating a constraint based microbial metabolism model with a reactive transport simulator as applied to bioremediation of uranium in groundwater. However, that work relied on an indirect coupling approach that was effective for initial demonstration but may not be extensible to more complex problems that are of significant interest (e.g., communities of microbial species, multiple constraining variables). Here, we extend that work by presenting and demonstrating a method of directly integrating a reactive transport model (FORTRAN code) with constraint-based in silico models solved with IBM ILOG CPLEX linear optimizer base system (C library). The models were integrated with BABEL, a language interoperability tool. The modeling system is designed in such a way that constraint-based models targeting different microorganisms or competing organism communities can be easily plugged into the system. Constraint-based modeling is very costly given the size of a genome-scale reaction network. To save computation time, a binary tree is traversed to examine the concentration and solution pool generated during the simulation in order to decide whether the constraint-based model should be called. We also show preliminary results from the integrated model including a comparison of the direct and indirect coupling approaches.

  18. Variably Saturated Flow and Multicomponent Biogeochemical Reactive Transport Modeling of a Uranium Bioremediation Field Experiment

    SciTech Connect (OSTI)

    Yabusaki, Steven B.; Fang, Yilin; Williams, Kenneth H.; Murray, Christopher J.; Ward, Anderson L.; Dayvault, Richard; Waichler, Scott R.; Newcomer, Darrell R.; Spane, Frank A.; Long, Philip E.

    2011-11-01T23:59:59.000Z

    Field experiments at a former uranium mill tailings site have identified the potential for stimulating indigenous bacteria to catalyze the conversion of aqueous uranium in the +6 oxidation state to immobile solid-associated uranium in the +4 oxidation state. This effectively removes uranium from solution resulting in groundwater concentrations below actionable standards. Three-dimensional, coupled variably-saturated flow and biogeochemical reactive transport modeling of a 2008 in situ uranium bioremediation field experiment is used to better understand the interplay of transport rates and biogeochemical reaction rates that determine the location and magnitude of key reaction products. A comprehensive reaction network, developed largely through previous 1-D modeling studies, was used to simulate the impacts on uranium behavior of pulsed acetate amendment, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. A principal challenge is the mechanistic representation of biologically-mediated terminal electron acceptor process (TEAP) reactions whose products significantly alter geochemical controls on uranium mobility through increases in pH, alkalinity, exchangeable cations, and highly reactive reduction products. In general, these simulations of the 2008 Big Rusty acetate biostimulation field experiment in Rifle, Colorado confirmed previously identified behaviors including (1) initial dominance by iron reducing bacteria that concomitantly reduce aqueous U(VI), (2) sulfate reducing bacteria that become dominant after {approx}30 days and outcompete iron reducers for the acetate electron donor, (3) continuing iron-reducer activity and U(VI) bioreduction during dominantly sulfate reducing conditions, and (4) lower apparent U(VI) removal from groundwater during dominantly sulfate reducing conditions. New knowledge on simultaneously active metal and sulfate reducers has been incorporated into the modeling. In this case, an initially small population of slow growing sulfate reducers is active from the initiation of biostimulation. Three-dimensional, variably saturated flow modeling was used to address impacts of a falling water table during acetate injection. These impacts included a significant reduction in aquifer saturated thickness and isolation of residual reactants and products, as well as unmitigated uranium, in the newly unsaturated vadose zone. High permeability sandy gravel structures resulted in locally high flow rates in the vicinity of injection wells that increased acetate dilution. In downgradient locations, these structures created preferential flow paths for acetate delivery that enhanced local zones of TEAP reactivity and subsidiary reactions. Conversely, smaller transport rates associated with the lower permeability lithofacies (e.g., fine) and vadose zone were shown to limit acetate access and reaction. Once accessed by acetate, however, these same zones limited subsequent acetate dilution and provided longer residence times that resulted in higher concentrations of TEAP products when terminal electron donors and acceptors were not limiting. Finally, facies-based porosity and reactive surface area variations were shown to affect aqueous uranium concentration distributions; however, the ranges were sufficiently small to preserve general trends. Large computer memory and high computational performance were required to simulate the detailed coupled process models for multiple biogeochemical components in highly resolved heterogeneous materials for the 110-day field experiment and 50 days of post-biostimulation behavior. In this case, a highly-scalable subsurface simulator operating on 128 processor cores for 12 hours was used to simulate each realization. An equivalent simulation without parallel processing would have taken 60 days, assuming sufficient memory was available.

  19. Upscaling of Long-Term U(VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

    SciTech Connect (OSTI)

    Steefel, Carl I.; Li Li; Davis, J.A.; Curtis, G.P.; Honeyman, B.D.; Kent, D.B.; Kohler, M.; Rodriguez, D.R.; Johnson, K.J.; Miller, A.

    2006-06-01T23:59:59.000Z

    The focus of the project is the development of scientifically defensible approaches for upscaling reactive transport models (RTM) through a detailed understanding of U(VI) desorption across several spatial scales: bench-, intermediate-, and field-scales. The central hypothesis of the project is that the development of this methodology will lead to a scientifically defensible approach for conceptual model development for multicomponent RTM at contaminated DOE sites, leading to predictive transport simulations with reduced uncertainty.

  20. Upscaling reactive transport in porous media : laboratory visualization and stochastic models

    E-Print Network [OSTI]

    Oates, Peter M. (Peter Michael), 1977-

    2007-01-01T23:59:59.000Z

    Solute transport models are essential tools for understanding and forecasting chemical concentrations in groundwater. Advection-dispersion based models can adequately predict spatial averages of conservative solute ...

  1. Final Report Coupling in silico microbial models with reactive transport models to predict the fate of contaminants in the subsurface.

    SciTech Connect (OSTI)

    Lovley, Derek R.

    2012-10-31T23:59:59.000Z

    This project successfully accomplished its goal of coupling genome-scale metabolic models with hydrological and geochemical models to predict the activity of subsurface microorganisms during uranium bioremediation. Furthermore, it was demonstrated how this modeling approach can be used to develop new strategies to optimize bioremediation. The approach of coupling genome-scale metabolic models with reactive transport modeling is now well enough established that it has been adopted by other DOE investigators studying uranium bioremediation. Furthermore, the basic principles developed during our studies will be applicable to much broader investigations of microbial activities, not only for other types of bioremediation, but microbial metabolism in diversity of environments. This approach has the potential to make an important contribution to predicting the impact of environmental perturbations on the cycling of carbon and other biogeochemical cycles.

  2. A model for reactive porous transport during re-wetting of hardened concrete

    E-Print Network [OSTI]

    Chapwanya, Michael; Stockie, John M

    2008-01-01T23:59:59.000Z

    We develop a mathematical model that captures the transport of liquid water in hardened concrete, as well as the chemical reactions that occur between the infiltrating water and the residual calcium silicate compounds that reside in the porous concrete matrix. We investigate the hypothesis that the reaction product -- calcium silicate hydrate gel -- clogs the pores within the concrete thereby hindering water transport. Using numerical simulations, we determine the sensitivity of the model solution to changes in various physical parameters, and compare to experimental results available in the literature.

  3. The effects of gas-fluid-rock interactions on CO2 injection and storage: Insights from reactive transport modeling

    SciTech Connect (OSTI)

    Xiao, Y.; Xu, T.; Pruess, K.

    2008-10-15T23:59:59.000Z

    Possible means of reducing atmospheric CO{sub 2} emissions include injecting CO{sub 2} in petroleum reservoirs for Enhanced Oil Recovery or storing CO{sub 2} in deep saline aquifers. Large-scale injection of CO{sub 2} into subsurface reservoirs would induce a complex interplay of multiphase flow, capillary trapping, dissolution, diffusion, convection, and chemical reactions that may have significant impacts on both short-term injection performance and long-term fate of CO{sub 2} storage. Reactive Transport Modeling is a promising approach that can be used to predict the spatial and temporal evolution of injected CO{sub 2} and associated gas-fluid-rock interactions. This presentation will summarize recent advances in reactive transport modeling of CO{sub 2} storage and review key technical issues on (1) the short- and long-term behavior of injected CO{sub 2} in geological formations; (2) the role of reservoir mineral heterogeneity on injection performance and storage security; (3) the effect of gas mixtures (e.g., H{sub 2}S and SO{sub 2}) on CO{sub 2} storage; and (4) the physical and chemical processes during potential leakage of CO{sub 2} from the primary storage reservoir. Simulation results suggest that CO{sub 2} trapping capacity, rate, and impact on reservoir rocks depend on primary mineral composition and injecting gas mixtures. For example, models predict that the injection of CO{sub 2} alone or co-injection with H{sub 2}S in both sandstone and carbonate reservoirs lead to acidified zones and mineral dissolution adjacent to the injection well, and carbonate precipitation and mineral trapping away from the well. Co-injection of CO{sub 2} with H{sub 2}S and in particular with SO{sub 2} causes greater formation alteration and complex sulfur mineral (alunite, anhydrite, and pyrite) trapping, sometimes at a much faster rate than previously thought. The results from Reactive Transport Modeling provide valuable insights for analyzing and assessing the dynamic behaviors of injected CO{sub 2}, identifying and characterizing potential storage sites, and managing injection performance and reducing costs.

  4. Pore Scale Modeling of the Reactive Transport of Chromium in the Cathode of a Solid Oxide Fuel Cell

    SciTech Connect (OSTI)

    Ryan, Emily M.; Tartakovsky, Alexandre M.; Recknagle, Kurtis P.; Khaleel, Mohammad A.; Amon, Cristina

    2011-01-01T23:59:59.000Z

    We present a pore scale model of a solid oxide fuel cell (SOFC) cathode. Volatile chromium species are known to migrate from the current collector of the SOFC into the cathode where over time they decrease the voltage output of the fuel cell. A pore scale model is used to investigate the reactive transport of chromium species in the cathode and to study the driving forces of chromium poisoning. A multi-scale modeling approach is proposed which uses a cell level model of the cathode, air channel and current collector to determine the boundary conditions for a pore scale model of a section of the cathode. The pore scale model uses a discrete representation of the cathode to explicitly model the surface reactions of oxygen and chromium with a cathode material. The pore scale model is used to study the reaction mechanisms of chromium by considering the effects of reaction rates, diffusion coefficients, chromium vaporization, and oxygen consumption on chromium’s deposition in the cathode. The study shows that chromium poisoning is most significantly affected by the chromium reaction rates in the cathode and that the reaction rates are a function of the local current density in the cathode.

  5. REACTIVE TRANSPORT MODELING USING A PARALLEL FULLY-COUPLED SIMULATOR BASED ON PRECONDITIONED JACOBIAN-FREE NEWTON-KRYLOV

    SciTech Connect (OSTI)

    Luanjing Guo; Chuan Lu; Hai Huang; Derek R. Gaston

    2012-06-01T23:59:59.000Z

    Systems of multicomponent reactive transport in porous media that are large, highly nonlinear, and tightly coupled due to complex nonlinear reactions and strong solution-media interactions are often described by a system of coupled nonlinear partial differential algebraic equations (PDAEs). A preconditioned Jacobian-Free Newton-Krylov (JFNK) solution approach is applied to solve the PDAEs in a fully coupled, fully implicit manner. The advantage of the JFNK method is that it avoids explicitly computing and storing the Jacobian matrix during Newton nonlinear iterations for computational efficiency considerations. This solution approach is also enhanced by physics-based blocking preconditioning and multigrid algorithm for efficient inversion of preconditioners. Based on the solution approach, we have developed a reactive transport simulator named RAT. Numerical results are presented to demonstrate the efficiency and massive scalability of the simulator for reactive transport problems involving strong solution-mineral interactions and fast kinetics. It has been applied to study the highly nonlinearly coupled reactive transport system of a promising in situ environmental remediation that involves urea hydrolysis and calcium carbonate precipitation.

  6. quantifying and Predicting Reactive Transport

    SciTech Connect (OSTI)

    Peter C. Burns, Department of Civil Engineering and Geological Sciences, University of Notre Dame

    2009-12-04T23:59:59.000Z

    This project was led by Dr. Jiamin Wan at Lawrence Berkeley National Laboratory. Peter Burns provided expertise in uranium mineralogy and in identification of uranium minerals in test materials. Dr. Wan conducted column tests regarding uranium transport at LBNL, and samples of the resulting columns were sent to Dr. Burns for analysis. Samples were analyzed for uranium mineralogy by X-ray powder diffraction and by scanning electron microscopy, and results were provided to Dr. Wan for inclusion in the modeling effort. Full details of the project can be found in Dr. Wan's final reports for the associated effort at LBNL.

  7. Stochastic modeling of transport and degradation of reactive solutes in heterogeneous aquifers

    E-Print Network [OSTI]

    Fadel, Ziad Joseph

    2006-08-16T23:59:59.000Z

    ? fate and transport have been reported in the literature (e.g. correlation between the sorption?s distribution coefficient Kd and the hydraulic conductivity [Allen-King et al., 1998; Robin et al., 1991]), whereas the connection between... KKKK hh + += -++- 1,,11,,1 , (23) where KA, KB, KC and KD (Eq. 24) represent the harmonic mean of the hydraulic conductivities related to the groundwater flow across two adjacent cells. Figure 8. Contour plot of a (100m x 10m) log...

  8. Multiphase flow and multicomponent reactive transport model of the ventilation experiment in Opalinus clay

    E-Print Network [OSTI]

    Zheng, L.

    2010-01-01T23:59:59.000Z

    Samper, J. , Zheng, L. , Montenegro, L. , 2006c. CoupledSamper, J. , Zheng, L. , Montenegro, L. , Fernández, A.M. ,A.M. Fernández and L. Montenegro, 2008b, Inverse modeling of

  9. Modeling reactive transport in deformable porous media using the theory of interacting continua.

    SciTech Connect (OSTI)

    Turner, Daniel Zack

    2012-01-01T23:59:59.000Z

    This report gives an overview of the work done as part of an Early Career LDRD aimed at modeling flow induced damage of materials involving chemical reactions, deformation of the porous matrix, and complex flow phenomena. The numerical formulation is motivated by a mixture theory or theory of interacting continua type approach to coupling the behavior of the fluid and the porous matrix. Results for the proposed method are presented for several engineering problems of interest including carbon dioxide sequestration, hydraulic fracturing, and energetic materials applications. This work is intended to create a general framework for flow induced damage that can be further developed in each of the particular areas addressed below. The results show both convincing proof of the methodologies potential and the need for further validation of the models developed.

  10. ALUMINOSILICATE-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS

    E-Print Network [OSTI]

    Flury, Markus

    ALUMINOSILICATE-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS By JORGE ANTONIO JEREZ transport experiments; Dr. Barbara Williams and Jason Shira from University of Idaho for providing access-COATED SILICA SAND FOR REACTIVE TRANSPORT EXPERIMENTS Abstract by Jorge Antonio Jerez Briones, Ph.D. Washington

  11. Groundwater Reactive Transport Models, 2012, 141-159 141 Fan Zhang, Gour-Tsyh (George) Yeh, Jack C. Parker and Xiaonan Shi (Eds)

    E-Print Network [OSTI]

    Mills, Richard

    performance computing, reactive transport, carbon sequestration, multiple realizations, multiphase flow transport at the Hanford 300 Area and CO2 sequestration in deep geologic formations. Keywords: High resources, such as CO2 sequestration in deep geologic formations, on the environment, and the efficacy

  12. Mulitdimensional reactive transport modeling of CO2 minreal sequestration in basalts at the Helllisheidi geothermal field, Iceland

    E-Print Network [OSTI]

    Aradottir, E.S.P.

    2013-01-01T23:59:59.000Z

    using the same kinetic expression as that for dissolution,used for the kinetic rate expression of different mineralsKinetic rates are a product of the rate constant and reactive surface area, according to the following general rate expression,

  13. System-Scale Model of Aquifer, Vadose Zone, and River Interactions for the Hanford 300 Area - Application to Uranium Reactive Transport

    SciTech Connect (OSTI)

    Rockhold, Mark L.; Bacon, Diana H.; Freedman, Vicky L.; Parker, Kyle R.; Waichler, Scott R.; Williams, Mark D.

    2013-10-01T23:59:59.000Z

    This report represents a synthesis and integration of basic and applied research into a system-scale model of the Hanford 300 Area groundwater uranium plume, supported by the U.S. Department of Energy’s Richland Operations (DOE-RL) office. The report integrates research findings and data from DOE Office of Science (DOE-SC), Office of Environmental Management (DOE-EM), and DOE-RL projects, and from the site remediation and closure contractor, Washington Closure Hanford, LLC (WCH). The three-dimensional, system-scale model addresses water flow and reactive transport of uranium for the coupled vadose zone, unconfined aquifer, and Columbia River shoreline of the Hanford 300 Area. The system-scale model of the 300 Area was developed to be a decision-support tool to evaluate processes of the total system affecting the groundwater uranium plume. The model can also be used to address “what if” questions regarding different remediation endpoints, and to assist in design and evaluation of field remediation efforts. For example, the proposed cleanup plan for the Hanford 300 Area includes removal, treatment, and disposal of contaminated sediments from known waste sites, enhanced attenuation of uranium hot spots in the vadose and periodically rewetted zone, and continued monitoring of groundwater with institutional controls. Illustrative simulations of polyphosphate infiltration were performed to demonstrate the ability of the system-scale model to address these types of questions. The use of this model in conjunction with continued field monitoring is expected to provide a rigorous basis for developing operational strategies for field remediation and for defining defensible remediation endpoints.

  14. Influence of calcite on uranium(VI) reactive transport in the groundwater–river mixing zone

    SciTech Connect (OSTI)

    Ma, Rui; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John M.; Zheng, Chunmiao

    2014-01-23T23:59:59.000Z

    Calcite is an important mineral that can affect uranyl reactive transport in subsurface sediments. This study investigated the distribution of calcite and its influence on uranyl adsorption and reactive transport in the groundwater-river mixing zone at US Hanford 300A, Washington State. Simulations using a 2D reactive transport model under field-relevant hydrogeochemical conditions revealed a complex distribution of calcite concentration as a result of dynamic groundwater-river interactions. The calcite concentration distribution in turn affected the spatial and temporal changes in aqueous carbonate, calcium, and pH, which subsequently influenced U(VI) mobility and discharge rates into the river. The results implied that calcite distribution and its concentration dynamics is an important consideration for field characterization, monitoring, and reactive transport prediction.

  15. Pore-scale simulation of microbial growth using a genome-scale metabolic model: Implications for Darcy-scale reactive transport

    SciTech Connect (OSTI)

    Tartakovsky, Guzel D.; Tartakovsky, Alexandre M.; Scheibe, Timothy D.; Fang, Yilin; Mahadevan, Radhakrishnan; Lovley, Derek R.

    2013-09-07T23:59:59.000Z

    Recent advances in microbiology have enabled the quantitative simulation of microbial metabolism and growth based on genome-scale characterization of metabolic pathways and fluxes. We have incorporated a genome-scale metabolic model of the iron-reducing bacteria Geobacter sulfurreducens into a pore-scale simulation of microbial growth based on coupling of iron reduction to oxidation of a soluble electron donor (acetate). In our model, fluid flow and solute transport is governed by a combination of the Navier-Stokes and advection-diffusion-reaction equations. Microbial growth occurs only on the surface of soil grains where solid-phase mineral iron oxides are available. Mass fluxes of chemical species associated with microbial growth are described by the genome-scale microbial model, implemented using a constraint-based metabolic model, and provide the Robin-type boundary condition for the advection-diffusion equation at soil grain surfaces. Conventional models of microbially-mediated subsurface reactions use a lumped reaction model that does not consider individual microbial reaction pathways, and describe reactions rates using empirically-derived rate formulations such as the Monod-type kinetics. We have used our pore-scale model to explore the relationship between genome-scale metabolic models and Monod-type formulations, and to assess the manifestation of pore-scale variability (microenvironments) in terms of apparent Darcy-scale microbial reaction rates. The genome-scale model predicted lower biomass yield, and different stoichiometry for iron consumption, in comparisonto prior Monod formulations based on energetics considerations. We were able to fit an equivalent Monod model, by modifying the reaction stoichiometry and biomass yield coefficient, that could effectively match results of the genome-scale simulation of microbial behaviors under excess nutrient conditions, but predictions of the fitted Monod model deviated from those of the genome-scale model under conditions in which one or more nutrients were limiting. The fitted Monod kinetic model was also applied at the Darcy scale; that is, to simulate average reaction processes at the scale of the entire pore-scale model domain. As we expected, even under excess nutrient conditions for which the Monod and genome-scale models predicted equal reaction rates at the pore scale, the Monod model over-predicted the rates of biomass growth and iron and acetate utilization when applied at the Darcy scale. This discrepancy is caused by an inherent assumption of perfect mixing over the Darcy-scale domain, which is clearly violated in the pore-scale models. These results help to explain the need to modify the flux constraint parameters in order to match observations in previous applications of the genome-scale model at larger scales. These results also motivate further investigation of quantitative multi-scale relationships between fundamental behavior at the pore scale (where genome-scale models are appropriately applied) and observed behavior at larger scales (where predictions of reactive transport phenomena are needed).

  16. Reactive transport modeling to study changes in water chemistry induced by CO2 injection at the Frio-I brine pilot

    SciTech Connect (OSTI)

    Kharaka, Y.K; Doughty, C.; Freifeld, B.M.; Daley, T.M.; Xu, T.

    2009-11-01T23:59:59.000Z

    To demonstrate the potential for geologic storage of CO{sub 2} in saline aquifers, the Frio-I Brine Pilot was conducted, during which 1600 tons of CO{sub 2} were injected into a high-permeability sandstone and the resulting subsurface plume of CO{sub 2} was monitored using a variety of hydrogeological, geophysical, and geochemical techniques. Fluid samples were obtained before CO{sub 2} injection for baseline geochemical characterization, during the CO{sub 2} injection to track its breakthrough at a nearby observation well, and after injection to investigate changes in fluid composition and potential leakage into an overlying zone. Following CO{sub 2} breakthrough at the observation well, brine samples showed sharp drops in pH, pronounced increases in HCO{sub 3}{sup -} and aqueous Fe, and significant shifts in the isotopic compositions of H{sub 2}O and dissolved inorganic carbon. Based on a calibrated 1-D radial flow model, reactive transport modeling was performed for the Frio-I Brine Pilot. A simple kinetic model of Fe release from the solid to aqueous phase was developed, which can reproduce the observed increases in aqueous Fe concentration. Brine samples collected after half a year had lower Fe concentrations due to carbonate precipitation, and this trend can be also captured by our modeling. The paper provides a method for estimating potential mobile Fe inventory, and its bounding concentration in the storage formation from limited observation data. Long-term simulations show that the CO{sub 2} plume gradually spreads outward due to capillary forces, and the gas saturation gradually decreases due to its dissolution and precipitation of carbonates. The gas phase is predicted to disappear after 500 years. Elevated aqueous CO{sub 2} concentrations remain for a longer time, but eventually decrease due to carbonate precipitation. For the Frio-I Brine Pilot, all injected CO{sub 2} could ultimately be sequestered as carbonate minerals.

  17. TWO-DIMENSIONAL REACTIVE TRANSPORT MODELING OF CO2 INJECTION IN A SALINE AQUIFER AT THE SLEIPNER SITE

    E-Print Network [OSTI]

    Boyer, Edmond

    model of long-term geological storage of carbon dioxide. A data set from the Utsira formation assemblages are considered in the Utsira formation, a sand formation that is highly permeable and a shale or gas reservoirs, (ii) unmineable coal beds and (iii) saline aquifers. Deep saline aquifers offer

  18. A transport based one-dimensional perturbation code for reactivity calculations in metal systems

    SciTech Connect (OSTI)

    Wenz, T.R.

    1995-02-01T23:59:59.000Z

    A one-dimensional reactivity calculation code is developed using first order perturbation theory. The reactivity equation is based on the multi-group transport equation using the discrete ordinates method for angular dependence. In addition to the first order perturbation approximations, the reactivity code uses only the isotropic scattering data, but cross section libraries with higher order scattering data can still be used with this code. The reactivity code obtains all the flux, cross section, and geometry data from the standard interface files created by ONEDANT, a discrete ordinates transport code. Comparisons between calculated and experimental reactivities were done with the central reactivity worth data for Lady Godiva, a bare uranium metal assembly. Good agreement is found for isotopes that do not violate the assumptions in the first order approximation. In general for cases where there are large discrepancies, the discretized cross section data is not accurately representing certain resonance regions that coincide with dominant flux groups in the Godiva assembly. Comparing reactivities calculated with first order perturbation theory and a straight {Delta}k/k calculation shows agreement within 10% indicating the perturbation of the calculated fluxes is small enough for first order perturbation theory to be applicable in the modeled system. Computation time comparisons between reactivities calculated with first order perturbation theory and straight {Delta}k/k calculations indicate considerable time can be saved performing a calculation with a perturbation code particularly as the complexity of the modeled problems increase.

  19. PARALLEL PROCESSING OF THREE-DIMENSIONAL FIELD-SCALE REACTIVE TRANSPORT APPLICATIONS

    E-Print Network [OSTI]

    Boyer, Edmond

    BRGM (French Geological Survey), Water Department, Groundwater and Geochemistry Modeling 3, Avenue C for the mixed hybrid finite element kernel. Com- putations of the reaction step are performed using a newly- tions. 1. INTRODUCTION The shape and scope of multi-component reactive transport models changed dramati

  20. Reactive transport of trace elements and isotopes in the Eutaw coastal plain aquifer, Alabama

    E-Print Network [OSTI]

    Wang, Yang

    geochemistry, mineralogy, and numerical modeling techniques to study the reactive transport of heavy metals ground- water geochemistry. Because the possible biogeochemical reactions in regional aquifers are quite suggest that that elevated metal concentrations may be derived from bacterial iron and manganese reduction

  1. Analytical solutions for sequentially coupled one-dimensional reactive transport problems Part I: Mathematical derivations

    E-Print Network [OSTI]

    Clement, Prabhakar

    Analytical solutions for sequentially coupled one-dimensional reactive transport problems ­ Part I-species reactive transport equations coupled through sorption and sequential first-order reactions are commonly. Although researchers have been attempting to solve various forms of these reactive transport equations

  2. STOMP-ECKEChem: An Engineering Perspective on Reactive Transport in Geologic Media

    SciTech Connect (OSTI)

    White, Mark D.; Fang, Yilin

    2012-04-04T23:59:59.000Z

    ECKEChem (Equilibrium, Conservation, Kinetic Equation Chemistry) is a reactive transport module for the STOMP suite of multifluid subsurface flow and transport simulators that was developed from an engineering perspective. STOMP comprises a suite of operational modes that are distinguished by the solved coupled conservation equations with capabilities for a variety of subsurface applications (e.g., environmental remediation and stewardship, geologic sequestration of greenhouse gases, gas hydrate production, and oil shale production). The ECKEChem module was designed to provide integrated reactive transport capabilities across the suite of STOMP simulator operational modes. The initial application for the ECKEChem module was in the simulation of the mineralization reactions that occurred with the injection of supercritical carbon dioxide into deep Columbia River basalt formations, where it was implemented in the STOMP-CO2 simulator. The STOMP-ECKEChem solution approach to modeling reactive transport in multifluid geologic media is founded on an engineering perspective: (1) sequential non-iterative coupling between the flow and reactive transport is sufficient, (2) reactive transport can be modeled by operator splitting with local geochemistry and global transport, (3) geochemistry can be expressed as a system of coupled nonlinear equilibrium, conservation and kinetic equations, (4) a limited number of kinetic equation forms are used in geochemical practice. This chapter describes the conceptual approach to converting a geochemical reaction network into a series of equilibrium, conservation and kinetic equations, the implementation of ECKEChem in STOMP, the numerical solution approach, and a demonstration of the simulator on a complex application involving desorption of uranium from contaminated field-textured sediments.

  3. Modeling Reactive Flows in Porous Media Peter Lichtner (lead PI), Los Alamos National Laboratory

    E-Print Network [OSTI]

    Mills, Richard

    and reactive transport in porous media. Apply it to field-scale studies of Geologic CO2 sequestrationModeling Reactive Flows in Porous Media Peter Lichtner (lead PI), Los Alamos National Laboratory NCCS Users Meeting March 28, 2007 #12;Introduction Companion to SciDAC-II project, "Modeling

  4. Modelling the long-term evolution of groundwater's quality in a flooded iron-ore mine using a reactive transport pipe network model

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modelling the long-term evolution of groundwater's quality in a flooded iron- ore mine using, groundwater quality, ePanet Introduction in lorraine (France), industrial mining began in the 19th century make classic groundwater modelling insuitable for predicting the impact of mining activities

  5. Analytical solutions for sequentially coupled one-dimensional reactive transport problems Part II: Special cases,

    E-Print Network [OSTI]

    Clement, Prabhakar

    Analytical solutions for sequentially coupled one-dimensional reactive transport problems ­ Part II solutions to multi-species reactive transport equations coupled through sorption and sequential first special-case transport scenarios involving zero initial condition, identical retardation factors and zero

  6. Comparison of parameter sensitivities between a laboratory and field scale model of uranium transport in a dual domain, distributed-rate reactive system

    SciTech Connect (OSTI)

    Greskowiak, Janek; Prommer, Henning; Liu, Chongxuan; Post, Vincent; Ma, Rui; Zheng, Chunmiao; Zachara, John M.

    2010-09-16T23:59:59.000Z

    A laboratory-derived conceptual and numerical model for U(VI) transport at the Hanford 300A site, Washington, USA, was applied to a range of field-scale scenarios of different complexity to systematically evaluate model parameter sensitivities. The model, originally developed from column experiment data, included distributed-rate surface complexation kinetics of U(VI), aqueous speciation, and physical non-equilibrium transport processes. A rigorous parameter sensitivity analysis was carried out with respect to different state variables: concentrations, mass fluxes, total mass and spatial moments of dissolved U(VI) for laboratory systems, and various simulation scenarios that represented the field-scale characteristics at the Hanford 300A site. The field-scenarios accounted for transient groundwater flow and variable geochemical conditions driven by frequent water level changes of the nearby Columbia River. Simulations indicated that the transient conditions significantly affected U(VI) plume migration at the site. The parameter sensitivities were largely similar between the laboratory and field scale systems. Where differences existed, they were shown to result from differing degrees of U(VI) adsorption disequilibrium caused by hydraulic or hydrogeochemical conditions. Adorption disequilibrium was found to differ (i) between short duration peak flow events at the field scale and much longer flow events in the laboratory, (ii) for changing groundwater chemical compositions due to river water intrusion, and (iii) for different sampling locations at the field scale. Parameter sensitivities were also found to vary with respect to the different investigated state variables. An approach is demonstrated that elucidates the most important parameters of a laboratory-scale model that must constrained in both the laboratory and field for meaningful field application.

  7. Transportation of a 40-year-old reactive mixed waste

    SciTech Connect (OSTI)

    Dietz, C.G. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1996-12-31T23:59:59.000Z

    Now a national landmark, Experimental Breeder Reactor-I was the worlds first nuclear reactor to produce a usable amount of commercial electricity in 1951. It is located on the Arco desert in Eastern Idaho at the Idaho National Engineering Laboratory (INEL). In 1955, the reactor experienced a cooling accident that resulted in core damage and a partial meltdown of the reactor, which left a serious cleanup challenge that had not been addressed until recently. The EBR-I reactor used liquid metal sodium-potassium (NaK) as a coolant because it is eutectic; that is, it remains a liquid at the lowest possible temperature and was a very effective coolant. NaK looks very much like mercury out of a thermometer. However, NaK is reactive and will burn in the presence of air (absorbing moisture from it) and is extremely reactive in direct contact with water, producing hydrogen. Furthermore, this highly reactive coolant was radioactively contaminated from the accident. Most of the radioactively contaminated NaK was processed and disposed of in 1955. However, approximately 180 gal of residual contaminated NaK remained because of the possibility it contained 10 1-gram foils of plutonium, which were in the reactor core at the time of the meltdown. This NaK was stored in four containers: two 55-gallon stainless steel transportation drums, one 60-gallon carbon steel container (used as a transfer vessel), and one 10-gallon carbon steel container (used to store radioactively contaminated water). This paper describes the transport of this waste from its temporary storage bunker to Argonne National Laboratory West for final treatment and preparation for disposal.

  8. Assessment of Controlling Processes for Field-Scale Uranium Reactive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    reactive transport model was employed to assess the key factors and processes that control the field-scale uranium reactive transport. Taking into consideration of relevant...

  9. Eoeective Recognizability and Model Checking of Reactive Fioeo Automata

    E-Print Network [OSTI]

    Sutre, Grégoire

    Electre. For this, we deøne a particular behavioral model for Electre programs, Reactive Fioeo Au­ tomata speciøed with the reactive language Electre [CR95]. A reactive pro­ gram is supposed to reactEoeective Recognizability and Model Checking of Reactive Fioeo Automata G. Sutre 1 , A. Finkel 1

  10. Chemically Reactive Working Fluids for the Capture and Transport...

    Broader source: Energy.gov (indexed) [DOE]

    More Documents & Publications Planar Optical Waveguide Coupler Transformers for High-Power Solar Enegy Collection and Transmission Chemically Reactive Working...

  11. Assessment of Controlling Processes for Field-Scale Uranium Reactive Transport under Highly Transient Flow Conditions

    SciTech Connect (OSTI)

    Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan; Greskowiak, Janek; Prommer, Henning; Zachara, John M.

    2014-02-13T23:59:59.000Z

    This paper presents the results of a comprehensive model-based analysis of a uranium tracer test conducted at the U.S Department of Energy Hanford 300 Area (300A) IFRC site. A three-dimensional multi-component reactive transport model was employed to assess the key factors and processes that control the field-scale uranium reactive transport. Taking into consideration of relevant physical and chemical processes, the selected conceptual/numerical model replicates the spatial and temporal variations of the observed U(VI) concentrations reasonably well in spite of the highly complex field conditions. A sensitivity analysis was performed to interrogate the relative importance of various processes and factors for reactive transport of U(VI) at the field-scale. The results indicate that multi-rate U(VI) sorption/desorption, U(VI) surface complexation reactions, and initial U(VI) concentrations were the most important processes and factors controlling U(VI) migration. On the other hand, cation exchange reactions, the choice of the surface complexation model, and dual-domain mass transfer processes, which were previously identified to be important in laboratory experiments, played less important roles under the field-scale experimental condition at the 300A site. However, the model simulations also revealed that the groundwater chemistry was relatively stable during the uranium tracer experiment and therefore presumably not dynamic enough to appropriately assess the effects of ion exchange reaction and the choice of surface complexation models on U(VI) sorption and desorption. Furthermore, it also showed that the field experimental duration (16 days) was not sufficiently long to precisely assess the role of a majority of the sorption sites that were accessed by slow kinetic processes within the dual domain model. The sensitivity analysis revealed the crucial role of the intraborehole flow that occurred within the long-screened monitoring wells and thus significantly affected both field-scale measurements and simulated U(VI) concentrations as a combined effect of aquifer heterogeneity and highly dynamic flow conditions. Overall, this study, which provides one of the few detailed and highly data-constrained uranium transport simulations, highlights the difference in controlling processes between laboratory and field scale that prevent a simple direct upscaling of laboratory-scale models.

  12. A Numerical Model for Miscible Displacement of Multi-Component Reactive Species

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . Azarouala a Water Department/Groundwater and Geochemistry Modeling, BRGM (French Geological Survey) 3 of our approach. Therefore, the model may prove useful for many practical applications. 1. INTRODUCTION Demands to undertake modeling analysis of coupled groundwater ow, solute transport, and reactive water

  13. Modeling of coupled heat transfer and reactive transport processes in porous media: Application to seepage studies at Yucca Mountain, Nevad a

    E-Print Network [OSTI]

    Mukhopadhyay, Sumit; Sonnenthal, Eric L.; Spycher, Nicolas

    2008-01-01T23:59:59.000Z

    1941) in this paper. Rock Properties Except for the fracturethe hydrological properties of the rock. A model based onthe hydraulic properties of the rock (such as porosity,

  14. FLOW AND REACTIVE TRANSPORT IN POROUS MEDIA INDUCED BY WELL INJECTION: SIMILARITY SOLUTION

    E-Print Network [OSTI]

    FLOW AND REACTIVE TRANSPORT IN POROUS MEDIA INDUCED BY WELL INJECTION: SIMILARITY SOLUTION C.J. VAN from laboratory batch experiments. Typical examples of isotherms are (see e.g. Freeze and Cherry [FC

  15. Characterization of materials for a reactive transport model validation experiment: Interim report on the caisson experiment. Yucca Mountain Site Characterization Project

    SciTech Connect (OSTI)

    Siegel, M.D.; Cheng, W.C. [Sandia National Labs., Albuquerque, NM (United States); Ward, D.B.; Bryan, C.R. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Earth and Planetary Sciences

    1995-08-01T23:59:59.000Z

    Models used in performance assessment and site characterization activities related to nuclear waste disposal rely on simplified representations of solute/rock interactions, hydrologic flow field and the material properties of the rock layers surrounding the repository. A crucial element in the design of these models is the validity of these simplifying assumptions. An intermediate-scale experiment is being carried out at the Experimental Engineered Test Facility at Los Alamos Laboratory by the Los Alamos and Sandia National Laboratories to develop a strategy to validate key geochemical and hydrological assumptions in performance assessment models used by the Yucca Mountain Site Characterization Project.

  16. Final Report Coupled In Silico Microbial and Geochemical Reactive Transport Models: Extension to Multi-Organism Communities, Upscaling, and Experimental Validation

    SciTech Connect (OSTI)

    Lovley, Derek R.

    2014-03-05T23:59:59.000Z

    The project was highly successful in improving the understanding of physiological and ecological factors controlling the growth and interaction of subsurface microorganisms and in developing better strategies for in silico modeling of the interactions of subsurface microorganisms with other species and their environment.

  17. Transport Model with Quasipions

    E-Print Network [OSTI]

    Xiong, L.; Ko, Che Ming; Koch, V.

    1993-01-01T23:59:59.000Z

    , the transport model that takes into account both nucleon-nucleon collisions and the nuclear mean-field po- tential (normally called the Ulasov-Uehling-Uhlenbeck or Boltzmann-Uehling-Uhlenbeck model [3]) have been ex- tended to include the pion degree... equation, the pion collision term is obtained from the imaginary part of its self-energy. In nuclear medium, the pion self-energy is modified by the strong p-wave pion- nucleon interaction. This not only afFects the production and absorption of the pion...

  18. PFLOTRAN: Reactive Flow & Transport Code for Use on Laptops to Leadership-Class Supercomputers

    SciTech Connect (OSTI)

    Hammond, Glenn E.; Lichtner, Peter C.; Lu, Chuan; Mills, Richard T.

    2012-04-18T23:59:59.000Z

    PFLOTRAN, a next-generation reactive flow and transport code for modeling subsurface processes, has been designed from the ground up to run efficiently on machines ranging from leadership-class supercomputers to laptops. Based on an object-oriented design, the code is easily extensible to incorporate additional processes. It can interface seamlessly with Fortran 9X, C and C++ codes. Domain decomposition parallelism is employed, with the PETSc parallel framework used to manage parallel solvers, data structures and communication. Features of the code include a modular input file, implementation of high-performance I/O using parallel HDF5, ability to perform multiple realization simulations with multiple processors per realization in a seamless manner, and multiple modes for multiphase flow and multicomponent geochemical transport. Chemical reactions currently implemented in the code include homogeneous aqueous complexing reactions and heterogeneous mineral precipitation/dissolution, ion exchange, surface complexation and a multirate kinetic sorption model. PFLOTRAN has demonstrated petascale performance using 2{sup 17} processor cores with over 2 billion degrees of freedom. Accomplishments achieved to date include applications to the Hanford 300 Area and modeling CO{sub 2} sequestration in deep geologic formations.

  19. Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    SciTech Connect (OSTI)

    Chorover, Jon; Perdrial, Nico; Mueller, Karl; Strepka, Caleb; Oà ƒ  ¢Ã ‚  € à ‚  ™ Day, Peggy; Rivera, Nelson; Um, Wooyong; Chang, Hyun-Shik; Steefel, Carl; Thompson, Aaron

    2012-11-05T23:59:59.000Z

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided thorough characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, partial pressure of carbon dioxide, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions. In this final report, we provide detailed descriptions of our results from this three-year study, completed in 2012 following a one-year no cost extension.

  20. Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions

    E-Print Network [OSTI]

    stored in poorly designed facilities or where it has been leached from U mill tailings [USDOE, 1996Simulation of reactive transport of uranium(VI) in groundwater with variable chemical conditions alluvial aquifer beneath a former U(VI) mill located near Naturita, CO, was simulated using a surface

  1. Transport Properties for Combustion Modeling

    E-Print Network [OSTI]

    Brown, N.J.

    2010-01-01T23:59:59.000Z

    a critical role in combustion processes just as chemicalparameters are essential for combustion modeling; molecularwith Application to Combustion. Transport Theor Stat 2003;

  2. Final Project Report: Release of aged contaminants from weathered sediments: Effects of sorbate speciation on scaling of reactive transport

    SciTech Connect (OSTI)

    Jon Chorover, University of Arizona; Peggy O' €  ™ Day, University of California, Merced; Karl Mueller, Penn State University; Wooyong Um, Pacific Northwest National Laboratory; Carl Steefel, Lawrence Berkeley National Laboratory

    2012-10-01T23:59:59.000Z

    Hanford sediments impacted by hyperalkaline high level radioactive waste have undergone incongruent silicate mineral weathering concurrent with contaminant uptake. In this project, we studied the impact of background pore water (BPW) on strontium, cesium and iodine desorption and transport in Hanford sediments that were experimentally weathered by contact with simulated hyperalkaline tank waste leachate (STWL) solutions. Using those lab-weathered Hanford sediments (HS) and model precipitates formed during nucleation from homogeneous STWL solutions (HN), we (i) provided detailed characterization of reaction products over a matrix of field-relevant gradients in contaminant concentration, PCO2, and reaction time; (ii) improved molecular-scale understanding of how sorbate speciation controls contaminant desorption from weathered sediments upon removal of caustic sources; and (iii) developed a mechanistic, predictive model of meso- to field-scale contaminant reactive transport under these conditions.

  3. Coupling lattice Boltzmann and continuum equations for flow and reactive transport in porous media.

    SciTech Connect (OSTI)

    Coon, Ethan [Los Alamos National Laboratory; Porter, Mark L. [Los Alamos National Laboratory; Kang, Qinjun [Los Alamos National Laboratory; Moulton, John D. [Los Alamos National Laboratory; Lichtner, Peter C. [Los Alamos National Laboratory

    2012-06-18T23:59:59.000Z

    In spatially and temporally localized instances, capturing sub-reservoir scale information is necessary. Capturing sub-reservoir scale information everywhere is neither necessary, nor computationally possible. The lattice Boltzmann Method for solving pore-scale systems. At the pore-scale, LBM provides an extremely scalable, efficient way of solving Navier-Stokes equations on complex geometries. Coupling pore-scale and continuum scale systems via domain decomposition. By leveraging the interpolations implied by pore-scale and continuum scale discretizations, overlapping Schwartz domain decomposition is used to ensure continuity of pressure and flux. This approach is demonstrated on a fractured medium, in which Navier-Stokes equations are solved within the fracture while Darcy's equation is solved away from the fracture Coupling reactive transport to pore-scale flow simulators allows hybrid approaches to be extended to solve multi-scale reactive transport.

  4. Predictive modeling of reactive wetting and metal joining.

    SciTech Connect (OSTI)

    van Swol, Frank B.

    2013-09-01T23:59:59.000Z

    The performance, reproducibility and reliability of metal joints are complex functions of the detailed history of physical processes involved in their creation. Prediction and control of these processes constitutes an intrinsically challenging multi-physics problem involving heating and melting a metal alloy and reactive wetting. Understanding this process requires coupling strong molecularscale chemistry at the interface with microscopic (diffusion) and macroscopic mass transport (flow) inside the liquid followed by subsequent cooling and solidification of the new metal mixture. The final joint displays compositional heterogeneity and its resulting microstructure largely determines the success or failure of the entire component. At present there exists no computational tool at Sandia that can predict the formation and success of a braze joint, as current capabilities lack the ability to capture surface/interface reactions and their effect on interface properties. This situation precludes us from implementing a proactive strategy to deal with joining problems. Here, we describe what is needed to arrive at a predictive modeling and simulation capability for multicomponent metals with complicated phase diagrams for melting and solidification, incorporating dissolutive and composition-dependent wetting.

  5. Semianalytical Solutions of Radioactive or Reactive Tracer Transport in Layered Fractured Media

    SciTech Connect (OSTI)

    G.J. Moridis; G. S. Bodvarsson

    2001-10-01T23:59:59.000Z

    In this paper, semianalytical solutions are developed for the problem of transport of radioactive or reactive tracers (solutes or colloids) through a layered system of heterogeneous fractured media with misaligned fractures. The tracer transport equations in the matrix account for (a) diffusion, (b) surface diffusion (for solutes only), (c) mass transfer between the mobile and immobile water fractions, (d) linear kinetic or equilibrium physical, chemical, or combined solute sorption or colloid filtration, and (e) radioactive decay or first order chemical reactions. Any number of radioactive decay daughter products (or products of a linear, first-order reaction chain) can be tracked. The tracer-transport equations in the fractures account for the same processes, in addition to advection and hydrodynamic dispersion. Additionally, the colloid transport equations account for straining and velocity adjustments related to the colloidal size. The solutions, which are analytical in the Laplace space, are numerically inverted to provide the solution in time and can accommodate any number of fractured and/or porous layers. The solutions are verified using analytical solutions for limiting cases of solute and colloid transport through fractured and porous media. The effect of important parameters on the transport of {sup 3}H, {sup 237}Np and {sup 239}Pu (and its daughters) is investigated in several test problems involving layered geological systems of varying complexity. {sup 239}Pu colloid transport problems in multilayered systems indicate significant colloid accumulations at straining interfaces but much faster transport of the colloid than the corresponding strongly sorbing solute species.

  6. Transportation Analysis, Modeling, and Simulation (TAMS) Application

    E-Print Network [OSTI]

    Transportation Analysis, Modeling, and Simulation (TAMS) Application Center for Transportation Passenger Flows Supply Chain Efficiency Transportation: Energy Environment Safety Security Vehicle Technologies T he Center for Transportation Analysis (CTA) TAMS application is a web-based tool that supports

  7. TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive geochemical Transport in Variable Saturated Geologic Media

    SciTech Connect (OSTI)

    Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

    2004-05-24T23:59:59.000Z

    Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of mineral alteration in hydrothermal systems, waste disposal sites, acid mine drainage remediation, contaminant transport, and groundwater quality. A comprehensive non-isothermal multi-component reactive fluid flow and geochemical transport simulator, TOUGHREACT, has been developed. A wide range of subsurface thermo-physical-chemical processes is considered under various thermohydrological and geochemical conditions of pressure, temperature, water saturation, and ionic strength. The program can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions are considered, such as aqueous complexation, gas dissolution/exsolution, and cation exchange. Mineral dissolution/precipitation can proceed either subject to local equilibrium or kinetic conditions. Changes in porosity and permeability due to mineral dissolution and precipitation can be considered. Linear adsorption and decay can be included. For the purpose of future extensions, surface complexation by double layer model is coded in the program. Xu and Pruess (1998) developed a first version of a non-isothermal reactive geochemical transport model, TOUGHREACT, by introducing reactive geochemistry into the framework of the existing multi-phase fluid and heat flow code TOUGH2 (Pruess, 1991). Xu, Pruess, and their colleagues have applied the program to a variety of problems such as: (1) supergene copper enrichment (Xu et al, 2001), (2) caprock mineral alteration in a hydrothermal system (Xu and Pruess, 2001a), and (3) mineral trapping for CO{sub 2} disposal in deep saline aquifers (Xu et al, 2003b and 2004a). For modeling the coupled thermal, hydrological, and chemical processes during heater tests at proposed nuclear waste disposal site at Yucca Mountain (Nevada), Sonnenthal and Spycher (2000) and Spycher et al. (2003) enhanced TOUGHREACT on (1) high temperature geochemistry, (2) mineral reactive surface area calculations, and (3) porosity and permeability changes due to mineral alteration. On the other hand, Pruess et al. (1999) updated the TOUGH2 simulator to TOUGH2 V2. The present version of TOUGHREACT was developed by introducing the work of Sonnenthal and Spycher (2000) to the original work of Xu and Pruess (1998), and by replacing TOUGH2 (Pruess, 1991) by TOUGH2 V2 (Pruess et al, 1999). The TOUGHREACT program makes use of ''self-documenting'' features. It is distributed with a number of input data files for sample problems. Besides providing benchmarks for proper code installation, these can serve as self-teaching tutorial in the use of TOUGHREACT, and they provide templates to help jump-start new applications. The fluid and heat flow part of TOUGHREACT is derived from TOUGH2 V2, so in addition to the current manual, users must have manual of the TOUGH2 V2 (Pruess et al., 1999). The present version of TOUGHREACT provides the following different TOUGH2 fluid property or ''EOS'' (equation-of-state) modules: (1) EOS1 for water, or two waters with typical applications to hydrothermal problems, (2) EOS2 for multiphase mixtures of water and CO{sub 2} also with typical applications to hydrothermal problems, (3) EOS3 for multiphase mixtures of water and air with typical applications to vadose zone and nuclear waste disposal problems, (4) EOS4 that has the same capabilities as EOS3 but with vapor pressure lowering effects due to capillary pressure, (5) EOS9 for single phase water (Richards. equation) with typical applications to ambient reactive geochemical transport problems, (6) ECO2 for multiphase mixtures of water, CO{sub 2} and NaCl with typical applications to CO{sub 2} disposal in deep brine aquifers.

  8. High Performance Computations of Subsurface Reactive Transport Processes at the Pore Scale

    E-Print Network [OSTI]

    such as carbon sequestration drive the geochemistry of porous media far from equilibrium in relatively short time in reservoir scale models. In the DOE Energy Frontier Research Center for Nanoscale Control of Geologic Carbon such as reactive surface area or reaction rates as they affect CO2 sequestration, with an objective of upscaling

  9. Semi-Analytical Solutions of One-Dimensional Multispecies Reactive Transport in a Permeable Reactive Barrier-Aquifer System

    E-Print Network [OSTI]

    Mieles, John Michael

    2012-07-16T23:59:59.000Z

    At many sites it has become apparent that most chemicals of concern (COCs) in groundwater are persistent and not effectively treated by conventional remediation methods. In recent years, the permeable reactive barrier (PRB) technology has proven...

  10. Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables

    E-Print Network [OSTI]

    Kumar, Ratnesh

    1 Finite Bisimulation of Reactive Untimed Infinite State Systems Modeled as Automata with Variables for reactive untimed infinite state systems called input- output extended finite automaton (I/O-EFA), which of a finite bisimilar abstraction. The results are illustrated through examples that model reactive software

  11. December 13, 2012 The steady state model of a reactive distillation column for ethylene glycol

    E-Print Network [OSTI]

    Neumaier, Arnold

    December 13, 2012 The steady state model of a reactive distillation column for ethylene glycol in an ethylene glycol reactive distillation column. Ind. Eng. Chem. Res., 33:2738­2748, 1994. 3 #12;

  12. Macroscopic Modeling of Transport Phenomena in

    E-Print Network [OSTI]

    Berning, Torsten

    Macroscopic Modeling of Transport Phenomena in Direct Methanol Fuel Cells Anders Christian Olesen, Denmark #12;Macroscopic Modeling of Transport Phenomena in Direct Methanol Fuel Cells Anders Christian transport phenomena govern- ing direct methanol fuel cell operation are analyzed, discussed and modeled

  13. TO APPEAR IN IEEE TRANSACTION ON POWER SYSTEMS 1 Effect of Reactive Power Limit Modeling on

    E-Print Network [OSTI]

    Cañizares, Claudio A.

    TO APPEAR IN IEEE TRANSACTION ON POWER SYSTEMS 1 Effect of Reactive Power Limit Modeling on Maximum System Loading and Active and Reactive Power Markets Behnam Tamimi, Student Member, IEEE, Claudio A. Ca- active power in electric power systems. Although there are other important reactive power sources

  14. Ecological Modelling 192 (2006) 143159 Nitrogen transformation and transport modeling

    E-Print Network [OSTI]

    Clement, Prabhakar

    model; Transformation; Transport; Nitrification; Denitrification; RT3D 1. Introduction Nitrogen of this paper are to develop a nitro- gen transport and transformation model for saturated groundwater systemsEcological Modelling 192 (2006) 143­159 Nitrogen transformation and transport modeling

  15. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    SciTech Connect (OSTI)

    B.W. ARNOLD

    2004-10-27T23:59:59.000Z

    The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.

  16. RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

    SciTech Connect (OSTI)

    S. Magnuson

    2004-11-01T23:59:59.000Z

    The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.

  17. Exact PDF equations and closure approximations for advective-reactive transport

    SciTech Connect (OSTI)

    Venturi, D.; Tartakovsky, Daniel M.; Tartakovsky, Alexandre M.; Karniadakis, George E.

    2013-06-01T23:59:59.000Z

    Mathematical models of advection–reaction phenomena rely on advective flow velocity and (bio) chemical reaction rates that are notoriously random. By using functional integral methods, we derive exact evolution equations for the probability density function (PDF) of the state variables of the advection–reaction system in the presence of random transport velocity and random reaction rates with rather arbitrary distributions. These PDF equations are solved analytically for transport with deterministic flow velocity and a linear reaction rate represented mathematically by a heterog eneous and strongly-correlated random field. Our analytical solution is then used to investigate the accuracy and robustness of the recently proposed large-eddy diffusivity (LED) closure approximation [1]. We find that the solution to the LED-based PDF equation, which is exact for uncorrelated reaction rates, is accurate even in the presence of strong correlations and it provides an upper bound of predictive uncertainty.

  18. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    ... ... Primary Energy Supplies Gas Coal Railroad, Barge ... ... Storage & Transportation Systems Energy Transportation Networks #12;Structural Model: Energy Flows GAS COAL ELECTRIC Case A: 2002, and the amount of electricity generated #12;Structural Model: Effects of Katrina Average natural gas nodal price

  19. Modeling Radionuclide Transport in Clays

    E-Print Network [OSTI]

    Zheng, L.

    2014-01-01T23:59:59.000Z

    Radionuclide Transport in Clays May 2012 Zheng, L. , J.a single sample of Opalinus Clay. Geochimica et Cosmochimicaadsorption onto kaolinite based clay minerals using FITEQL

  20. Performance Assessment Transport Modeling of Uranium at the Area 5 Radioactive Waste Management Site at the Nevada National Security Site

    SciTech Connect (OSTI)

    NSTec Radioactive Waste

    2010-10-12T23:59:59.000Z

    Following is a brief summary of the assumptions that are pertinent to the radioactive isotope transport in the GoldSim Performance Assessment model of the Area 5 Radioactive Waste Management Site, with special emphasis on the water-phase reactive transport of uranium, which includes depleted uranium products.

  1. A three-dimensional model of microbial transport and biodegradation at the Schoolcraft, Michigan, site

    E-Print Network [OSTI]

    ; revised 3 January 2005; accepted 21 January 2005; published 13 May 2005. [1] Bioremediation can be a cost-dimensional reactive transport modeling of carbon tetrachloride (CT) bioremediation at the Schoolcraft site in western success- ful application of bioremediation has been documented at several sites containing chlorinated

  2. Reactive transport modeling for CO2 geological sequestration

    E-Print Network [OSTI]

    Xu, T.

    2013-01-01T23:59:59.000Z

    of lead and arsenic on goethite, illite, kaolinite, and9.0594E-06 Kerogen-os Goethite Assumed at equilibrium pyrite

  3. DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE 

    E-Print Network [OSTI]

    Aluko, Obanifemi

    2010-01-16T23:59:59.000Z

    This work presents a modeling and control study of a reactive distillation column used for hydrogenation of benzene. A steady state and a dynamic model have been developed to investigate control structures for the column. The most important aspects...

  4. TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1

    SciTech Connect (OSTI)

    Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

    2008-09-29T23:59:59.000Z

    Coupled modeling of subsurface multiphase fluid and heat flow, solute transport, and chemical reactions can be applied to many geologic systems and environmental problems, including geothermal systems, diagenetic and weathering processes, subsurface waste disposal, acid mine drainage remediation, contaminant transport, and groundwater quality. TOUGHREACT has been developed as a comprehensive non-isothermal multi-component reactive fluid flow and geochemical transport simulator to investigate these and other problems. A number of subsurface thermo-physical-chemical processes are considered under various thermohydrological and geochemical conditions of pressure, temperature, water saturation, and ionic strength. TOUGHREACT can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The code can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions are considered, such as aqueous complexation, gas dissolution/exsolution, and cation exchange. Mineral dissolution/precipitation can take place subject to either local equilibrium or kinetic controls, with coupling to changes in porosity and permeability and capillary pressure in unsaturated systems. Chemical components can also be treated by linear adsorption and radioactive decay. The first version of the non-isothermal reactive geochemical transport code TOUGHREACT was developed (Xu and Pruess, 1998) by introducing reactive geochemistry into the framework of the existing multi-phase fluid and heat flow code TOUGH2 (Pruess, 1991). TOUGHREACT was further enhanced with the addition of (1) treatment of mineral-water-gas reactive-transport under boiling conditions, (2) an improved HKF activity model for aqueous species, (3) gas species diffusion coefficients calculated as a function of pressure, temperature, and molecular properties, (4) mineral reactive surface area formulations for fractured and porous media, and (5) porosity, permeability, and capillary pressure changes owing to mineral precipitation/dissolution (Sonnenthal et al., 1998, 2000, 2001; Spycher et al., 2003a). Subsequently, TOUGH2 V2 was released with additional EOS modules and features (Pruess et al., 1999). The present version of TOUGHREACT includes all of the previous extensions to the original version, along with the replacement of the original TOUGH2 (Pruess, 1991) by TOUGH2 V2 (Pruess et al., 1999). TOUGHREACT has been applied to a wide variety of problems, some of which are included as examples, such as: (1) Supergene copper enrichment (Xu et al., 2001); (2) Mineral alteration in hydrothermal systems (Xu and Pruess, 2001a; Xu et al., 2004b; Dobson et al., 2004); (3) Mineral trapping for CO{sub 2} disposal in deep saline aquifers (Xu et al., 2003b and 2004a); (4) Coupled thermal, hydrological, and chemical processes in boiling unsaturated tuff for the proposed nuclear waste emplacement site at Yucca Mountain, Nevada (Sonnenthal et al., 1998, 2001; Sonnenthal and Spycher, 2000; Spycher et al., 2003a, b; Xu et al., 2001); (5) Modeling of mineral precipitation/dissolution in plug-flow and fracture-flow experiments under boiling conditions (Dobson et al., 2003); (6) Calcite precipitation in the vadose zone as a function of net infiltration (Xu et al., 2003); and (7) Stable isotope fractionation in unsaturated zone pore water and vapor (Singleton et al., 2004). The TOUGHREACT program makes use of 'self-documenting' features. It is distributed with a number of input data files for sample problems. Besides providing benchmarks for proper code installation, these can serve as a self-teaching tutorial in the use of TOUGHREACT, and they provide templates to help jump-start new applications. The fluid and heat flow part of TOUGHREACT is derived from TOUGH2 V2, so in addition to the current manual, users must have the manual of the TOUGH2 V2 (Pruess et al., 1999). The present version of TOUGHREACT provides the following TOUGH2 fluid property or 'EOS' (equation-of-state) modules: (1) EOS1 for

  5. A Many-Task Parallel Approach for Multiscale Simulations of Subsurface Flow and Reactive Transport

    SciTech Connect (OSTI)

    Scheibe, Timothy D.; Yang, Xiaofan; Schuchardt, Karen L.; Agarwal, Khushbu; Chase, Jared M.; Palmer, Bruce J.; Tartakovsky, Alexandre M.

    2014-12-16T23:59:59.000Z

    Continuum-scale models have long been used to study subsurface flow, transport, and reactions but lack the ability to resolve processes that are governed by pore-scale mixing. Recently, pore-scale models, which explicitly resolve individual pores and soil grains, have been developed to more accurately model pore-scale phenomena, particularly reaction processes that are controlled by local mixing. However, pore-scale models are prohibitively expensive for modeling application-scale domains. This motivates the use of a hybrid multiscale approach in which continuum- and pore-scale codes are coupled either hierarchically or concurrently within an overall simulation domain (time and space). This approach is naturally suited to an adaptive, loosely-coupled many-task methodology with three potential levels of concurrency. Each individual code (pore- and continuum-scale) can be implemented in parallel; multiple semi-independent instances of the pore-scale code are required at each time step providing a second level of concurrency; and Monte Carlo simulations of the overall system to represent uncertainty in material property distributions provide a third level of concurrency. We have developed a hybrid multiscale model of a mixing-controlled reaction in a porous medium wherein the reaction occurs only over a limited portion of the domain. Loose, minimally-invasive coupling of pre-existing parallel continuum- and pore-scale codes has been accomplished by an adaptive script-based workflow implemented in the Swift workflow system. We describe here the methods used to create the model system, adaptively control multiple coupled instances of pore- and continuum-scale simulations, and maximize the scalability of the overall system. We present results of numerical experiments conducted on NERSC supercomputing systems; our results demonstrate that loose many-task coupling provides a scalable solution for multiscale subsurface simulations with minimal overhead.

  6. Modeling of Hydrogen Storage Materials: A Reactive Force Field for NaH

    E-Print Network [OSTI]

    Goddard III, William A.

    range transport mechanism of Al during the dissociation process. Briefly, the conventional (de to accurately predict the dynamical and reactive processes in hydrocarbons [2], sihcon/sihcon oxides [3 for hydrocarbons[5], ReaxFF has been successfully applied to study Si/Si02 interfaces[3], MgH2 systems and Al

  7. Multiphase transport model for relativistic nuclear collisions 

    E-Print Network [OSTI]

    Zhang, B.; Ko, Che Ming; Li, Ba; Lin, ZW.

    2000-01-01T23:59:59.000Z

    To study heavy ion collisions at energies available from the Relativistic Heavy Ion Collider (RHIC), we have developed a multiphase transport model that includes both initial partonic and final hadronic interactions. Specifically, the Zhang's parton...

  8. Multiphase transport model for relativistic nuclear collisions

    E-Print Network [OSTI]

    Zhang, B.; Ko, Che Ming; Li, Ba; Lin, ZW.

    2000-01-01T23:59:59.000Z

    To study heavy ion collisions at energies available from the Relativistic Heavy Ion Collider (RHIC), we have developed a multiphase transport model that includes both initial partonic and final hadronic interactions. Specifically, the Zhang's parton...

  9. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    emissions prices? How would CO2 regulations impact coal, gas, electricity, & SO2 markets? 3. Disruptions1 Decision Models for Bulk Energy Transportation Networks Electrical Engineering Professor Jim Mc: · integrated fuel, electricity networks · environmental impacts · electricity commodity markets · behavior

  10. Highway and interline transportation routing models

    SciTech Connect (OSTI)

    Joy, D.S.; Johnson, P.E.

    1994-06-01T23:59:59.000Z

    The potential impacts associated with the transportation of hazardous materials are important issues to shippers, carriers, and the general public. Since transportation routes are a central characteristic in most of these issues, the prediction of likely routes is the first step toward the resolution of these issues. In addition, US Department of Transportation requirements (HM-164) mandate specific routes for shipments of highway controlled quantities of radioactive materials. In response to these needs, two routing models have been developed at Oak Ridge National Laboratory under the sponsorship of the U.S. Department of Energy (DOE). These models have been designated by DOE`s Office of Environmental Restoration and Waste Management, Transportation Management Division (DOE/EM) as the official DOE routing models. Both models, HIGHWAY and INTERLINE, are described.

  11. Resonant charge-exchange involving excited helium atoms and reactive transport of local thermodynamic equilibrium helium plasma

    SciTech Connect (OSTI)

    Kosarim, A. V.; Smirnov, B. M. [Joint Institute for High Temperatures RAS, Moscow (Russian Federation); Laricchiuta, A. [CNR IMIP Bari, Bari (Italy); Capitelli, M. [CNR IMIP Bari, Bari (Italy); Department of Chemistry, University of Bari, Bari (Italy)

    2012-06-15T23:59:59.000Z

    The cross sections for charge-exchange and charge-transfer processes are evaluated for collisions of helium ions with parent-atoms in ground and excited states, with the principal quantum number n= 1-5, in the collision energy range from thermal up to 10 eV. Corresponding diffusion-type collision integrals are derived, and the role of 'abnormal' transport of electronically excited states on the reactive thermal conductivity of equilibrium helium plasma, at atmospheric pressure, estimated in the frame of a simplified approach.

  12. Psychophysiological Reactivity to Self and Model Images in an Upward Social Comparison Manipulation

    E-Print Network [OSTI]

    Tamez, Jeannine

    2012-02-14T23:59:59.000Z

    The current study examined affective reactivity to oneself in an upward socialcomparison manipulation using autonomic physiological responses. Study I was conducted to select images of thin and average size models used to elicit a social comparison...

  13. Social comparison test using women's subjective and physiological reactivity to thin and average size models

    E-Print Network [OSTI]

    Tamez, Jeannine Paola

    2009-05-15T23:59:59.000Z

    The current study examined the subjective and physiological reactivity to body image stimuli among females engaging in a social comparison task. Study I was conducted to select images of thin and average size models and neutral objects for Study...

  14. Coupled modeling of non-isothermal multiphase flow, solutetransport and reactive chemistry in porous and fractured media: 1. ModelDevelopment and Validation

    SciTech Connect (OSTI)

    Xu, Tianfu; Pruess, Karsten

    1998-09-01T23:59:59.000Z

    Coupled modeling of subsurface multiphase fluid and heat flow, solute transport and chemical reactions can be used for the assessment of acid mine drainage remediation, mineral deposition, waste disposal sites, hydrothermal convection, contaminant transport, and groundwater quality. Here they present a numerical simulation model, TOUGHREACT, which considers non-isothermal multi-component chemical transport in both liquid and gas phases. A wide range of subsurface thermo-physical-chemical processes is considered. The model can be applied to one-, two- or three-dimensional porous and fractured media with physical and chemical heterogeneity. The model can accommodate any number of chemical species present in liquid, gas and solid phases. A variety of equilibrium chemical reactions is considered, such as aqueous complexation, gas dissolution/exsolution, cation exchange, and surface complexation. Mineral dissolution/precipitation can proceed either subject to local equilibrium or kinetic conditions. The coupled model employs a sequential iteration approach with reasonable computing efficiency. The development of the governing equations and numerical approach is presented along with the discussion of the model implementation and capabilities. The model is verified for a wide range of subsurface physical and chemical processes. The model is well suited for flow and reactive transport in variably saturated porous and fractured media. In the second of this two-part paper, three applications covering a variety of problems are presented to illustrate the capabilities of the model.

  15. Reactive geochemical transport simulation to study mineral trapping for CO2 disposal in deep saline arenaceous aquifers

    SciTech Connect (OSTI)

    Xu, Tianfu; Apps, John A.; Pruess, Karsten

    2002-04-01T23:59:59.000Z

    A reactive fluid flow and geochemical transport numerical model for evaluating long-term CO{sub 2} disposal in deep aquifers has been developed. Using this model, we performed a number of sensitivity simulations under CO{sub 2} injection conditions for a commonly encountered Gulf Coast sediment to analyze the impact of CO{sub 2} immobilization through carbonate precipitation. Geochemical models are needed because alteration of the predominant host rock aluminosilicate minerals is very slow and is not amenable to laboratory experiment under ambient deep-aquifer conditions. Under conditions considered in our simulations, CO{sub 2} trapping by secondary carbonate minerals such as calcite (CaCO{sub 3}), dolomite (CaMg(CO{sub 3}){sub 2}), siderite (FeCO{sub 3}), and dawsonite (NaAlCO{sub 3}(OH){sub 2}) could occur in the presence of high pressure CO{sub 2}. Variations in precipitation of secondary carbonate minerals strongly depend on rock mineral composition and their kinetic reaction rates. Using the data presented in this paper, CO{sub 2} mineral-trapping capability after 10,000 years is comparable to CO{sub 2} dissolution in pore waters (2-5 kg CO{sub 2} per cubic meter of formation). Under favorable conditions such as increase of the Mg-bearing mineral clinochlore (Mg{sub 5}Al{sub 2}Si{sub 3}O{sub 10}(OH){sub 8}) abundance, the capacity can be larger (10 kg CO{sub 2} per cubic meter of formation) due to increase of dolomite precipitation. Carbon dioxide-induced rock mineral alteration and the addition of CO{sub 2} mass as secondary carbonates to the solid matrix results in decreases in porosity. A maximum 3% porosity decrease is obtained in our simulations. A small decrease in porosity may result in a significant decrease in permeability. The numerical simulations described here provide useful insight into sequestration mechanisms, and their controlling conditions and parameters.

  16. Diffusion Dominant Solute Transport Modelling In Deep Repository Under The Effect of Emplacement Media Degradation - 13285

    SciTech Connect (OSTI)

    Kwong, S. [National Nuclear Laboratory (United Kingdom)] [National Nuclear Laboratory (United Kingdom); Jivkov, A.P. [Research Centre for Radwaste and Decommissioning and Modelling and Simulation Centre, University of Manchester (United Kingdom)] [Research Centre for Radwaste and Decommissioning and Modelling and Simulation Centre, University of Manchester (United Kingdom)

    2013-07-01T23:59:59.000Z

    Deep geologic disposal of high activity and long-lived radioactive waste is being actively considered and pursued in many countries, where low permeability geological formations are used to provide long term waste contaminant with minimum impact to the environment and risk to the biosphere. A multi-barrier approach that makes use of both engineered and natural barriers (i.e. geological formations) is often used to further enhance the containment performance of the repository. As the deep repository system subjects to a variety of thermo-hydro-chemo-mechanical (THCM) effects over its long 'operational' lifespan (e.g. 0.1 to 1.0 million years, the integrity of the barrier system will decrease over time (e.g. fracturing in rock or clay)). This is broadly referred as media degradation in the present study. This modelling study examines the effects of media degradation on diffusion dominant solute transport in fractured media that are typical of deep geological environment. In particular, reactive solute transport through fractured media is studied using a 2-D model, that considers advection and diffusion, to explore the coupled effects of kinetic and equilibrium chemical processes, while the effects of degradation is studied using a pore network model that considers the media diffusivity and network changes. Model results are presented to demonstrate the use of a 3D pore-network model, using a novel architecture, to calculate macroscopic properties of the medium such as diffusivity, subject to pore space changes as the media degrade. Results from a reactive transport model of a representative geological waste disposal package are also presented to demonstrate the effect of media property change on the solute migration behaviour, illustrating the complex interplay between kinetic biogeochemical processes and diffusion dominant transport. The initial modelling results demonstrate the feasibility of a coupled modelling approach (using pore-network model and reactive transport model) to examine the long term behaviour of deep geological repositories with media property change under complex geochemical conditions. (authors)

  17. Reactive facies: An approach for parameterizing field-scale reactive transport models using geophysical methods

    E-Print Network [OSTI]

    Hubbard, Susan

    Miles.denham@srnl.doe.gov 803-725-5521 Environmental Science and Biotechnology Savannah River National National Lab 1 Cyclotron Road Mail Stop 90R1116 Berkeley, CA 94720- 8126 Susan S. Hubbard 510-486-5266 SSHubbard@lbl.gov Lawrence Berkeley National Lab 1 Cyclotron Road Mail Stop 90R1116 Berkeley, CA 94720- 8126

  18. Reactive facies: An approach for parameterizing field-scale reactive transport models using geophysical methods

    E-Print Network [OSTI]

    Sassen, D.

    2014-01-01T23:59:59.000Z

    source rock (organic rich sedimen- tary rocks versus silicate dominated igneous and metamor- phic rocks) and to differences in sediment maturity (

  19. Radionuclide Transport Models Under Ambient Conditions

    SciTech Connect (OSTI)

    G. Moridis; Q. Hu

    2001-12-20T23:59:59.000Z

    The purpose of Revision 00 of this Analysis/Model Report (AMR) is to evaluate (by means of 2-D semianalytical and 3-D numerical models) the transport of radioactive solutes and colloids in the unsaturated zone (UZ) under ambient conditions from the potential repository horizon to the water table at Yucca Mountain (YM), Nevada.

  20. Interactive coastal oil spill transport model 

    E-Print Network [OSTI]

    Thalasila, Nanda K.

    1992-01-01T23:59:59.000Z

    INTERACTIVE COASTAL OIL SPILL TRANSPORT MODEL A Thesis by NANDA K. THALASILA Submitted to the OIIice of Graduate Studies of Texas A8zM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1992 Major... Subject: Civil Engineering INTERACTIVE COASTAL OIL SPILL TRANSPORT MODEL A Thesis by NANDA K. THALASILA Approved a, s to style and content by: Roy W. Harm Chair of C mittee) Richard A. artzman (Member) om D. olds (Member) Dr Jame T P. Yao...

  1. Abstract--This paper proposes a reactive power dispatch model that takes into account both the technical and economical

    E-Print Network [OSTI]

    Cañizares, Claudio A.

    the reactive power and voltage control practices in all North American Electric Reliability Council (NERC and transformers taps deviations [12]. In the context of deregulated electricity markets, reactive power dispatch1 Abstract--This paper proposes a reactive power dispatch model that takes into account both

  2. Climate Impact of Transportation A Model Comparison

    SciTech Connect (OSTI)

    Girod, Bastien; Van Vuuren, Detlef; Grahn, Maria; Kitous, Alban; Kim, Son H.; Kyle, G. Page

    2013-06-01T23:59:59.000Z

    Transportation contributes to a significant and rising share of global energy use and GHG emissions. Therefore modeling future travel demand, its fuel use, and resulting CO2 emission is highly relevant for climate change mitigation. In this study we compare the baseline projections for global service demand (passenger-kilometers, ton-kilometers), fuel use, and CO2 emissions of five different global transport models using harmonized input assumptions on income and population. For four models we also evaluate the impact of a carbon tax. All models project a steep increase in service demand over the century. Technology is important for limiting energy consumption and CO2 emissions, but quite radical changes in the technology mix are required to stabilize or reverse the trend. While all models project liquid fossil fuels dominating up to 2050, they differ regarding the use of alternative fuels (natural gas, hydrogen, biofuels, and electricity), because of different fuel price projections. The carbon tax of US$200/tCO2 in 2050 stabilizes or reverses global emission growth in all models. Besides common findings many differences in the model assumptions and projections indicate room for improvement in modeling and empirical description of the transport system.

  3. Modeling chamber transport for heavy-ion fusion

    E-Print Network [OSTI]

    2002-01-01T23:59:59.000Z

    Modeling Chamber Transport for Heavy-Ion Fusion W. M. Sharp,Peterson, "Chamber Transport of 'Foot' Pulses for Heavy-Ionstate of beam ions. Although several chamber- transport

  4. Model for assessing bronchial mucus transport

    SciTech Connect (OSTI)

    Agnew, J.E.; Bateman, J.R.M.; Pavia, D.; Clarke, S.W.

    1984-02-01T23:59:59.000Z

    The authors propose a scheme for the assessment of regional mucus transport using inhaled Tc-99m aerosol particles and quantitative analysis of serial gamma-camera images. The model treats input to inner and intermediate lung regions as the total of initial deposition there plus subsequent transport into these regions from more peripheral airways. It allows for interregional differences in the proportion of particles deposited on the mucus-bearing conducting airways, and does not require a gamma image 24 hr after particle inhalation. Instead, distribution of particles reaching the respiratory bronchioles or alveoli is determined from a Kr-81m ventilation image, while the total amount of such deposition is obtained from 24-hr Tc-99m retention measured with a sensitive counter system. The model is applicable to transport by mucociliary action or by cough, and has been tested in ten normal and ten asthmatic subjects.

  5. TOURGHREACT: A Simulation Program for Non-isothermal MultiphaseReactive Geochemical Transport in Variably Saturated GeologicMedia

    SciTech Connect (OSTI)

    Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

    2004-12-07T23:59:59.000Z

    TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media. The program was written in Fortran 77 and developed by introducing reactive geochemistry into the multiphase fluid and heat flow simulator TOUGH2. A variety of subsurface thermo-physical-chemical processes are considered under a wide range of conditions of pressure, temperature, water saturation, ionic strength, and pH and Eh. Interactions between mineral assemblages and fluids can occur under local equilibrium or kinetic rates. The gas phase can be chemically active. Precipitation and dissolution reactions can change formation porosity and permeability. The program can be applied to many geologic systems and environmental problems, including geothermal systems, diagenetic and weathering processes, subsurface waste disposal, acid mine drainage remediation, contaminant transport, and groundwater quality. Here we present two examples to illustrate applicability of the program: (1) injectivity effects of mineral scaling in a fractured geothermal reservoir and (2) CO2 disposal in a deep saline aquifer.

  6. Modelling Additive Transport in Metal Halide Lamps

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    doctor aan de Technische Universiteit Eindhoven, op gezag van de Rector Magnificus, prof.dr.ir. C.J. van-DATA LIBRARY TECHNISCHE UNIVERSITEIT EINDHOVEN Beks, Mark Louwrens Modelling Additive Transport in Metal Halide Lamps/ door Beks, M.L. - Eindhoven : Technische Universiteit Eindhoven, 2008. Proefschrift. ISBN: 978

  7. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    E-Print Network [OSTI]

    Liu, Hui-Hai

    2010-01-01T23:59:59.000Z

    International Workshop on Geomechanics, hydromechanical andflow, heat transport and geomechanics, by linking the twotransport modeling and geomechanics using the reactive

  8. Transport Analysis of Trace Tritium Experiments on JET using TRANSP Code and Comparison with Theory-Based Transport Models

    E-Print Network [OSTI]

    Transport Analysis of Trace Tritium Experiments on JET using TRANSP Code and Comparison with Theory-Based Transport Models

  9. Kinematic and dynamic model-based control of wheeled mobile manipulators: a unified framework for reactive approaches

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Kinematic and dynamic model-based control of wheeled mobile manipulators: a unified framework aims at providing a unified modeling framework for the reactive control of wheeled mobile manipulators systems is given. This modeling framework is particularly well suited for reactive control approaches

  10. Analytical mesoscale modeling of aeolian sand transport

    E-Print Network [OSTI]

    Marc Lämmel; Anne Meiwald; Klaus Kroy

    2014-05-03T23:59:59.000Z

    We analyze the mesoscale structure of aeolian sand transport, based on a recently developed two-species continuum model. The calculated sand flux and important average characteristics of the grain trajectories are found to be in remarkable agreement with field and wind-tunnel data. We conclude that the essential mesoscale physics is insensitive to unresolved details on smaller scales and well captured by the coarse-grained analytical model, thus providing a sound basis for precise and numerically efficient mesoscale modeling of aeolian structure formation.

  11. Nanoscale study of reactive transport in catalyst layer of proton exchange membrane fuel cells with precious and non-precious catalysts using lattice Boltzmann method

    E-Print Network [OSTI]

    Chen, Li; Kang, Qinjun; Holby, Edward F; Tao, Wen-Quan

    2014-01-01T23:59:59.000Z

    High-resolution porous structures of catalyst layer (CL) with multicomponent in proton exchange membrane fuel cells are reconstructed using a reconstruction method called quartet structure generation set. Characterization analyses of nanoscale structures are implemented including pore size distribution, specific area and phase connectivity. Pore-scale simulation methods based on the lattice Boltzmann method are developed and used to predict the macroscopic transport properties including effective diffusivity and proton conductivity. Nonuniform distributions of ionomer in CL generates more tortuous pathway for reactant transport and greatly reduces the effective diffusivity. Tortuosity of CL is much higher than conventional Bruggeman equation adopted. Knudsen diffusion plays a significant role in oxygen diffusion and significantly reduces the effective diffusivity. Reactive transport inside the CL is also investigated. Although the reactive surface area of non-precious metal catalyst (NPMC) CL is much higher t...

  12. Multimodal Transport Modeling for Nairobi, Kenya: Insights and Recommendations with an Evidence-Based Model

    E-Print Network [OSTI]

    California at Berkeley, University of

    Multimodal Transport Modeling for Nairobi, Kenya: Insights and Recommendations with an Evidence-5 August 2009 #12;Multimodal Transport Modeling for Nairobi, Kenya: Insights and Recommendations

  13. Reactive self-heating model of aluminum spherical nanoparticles

    E-Print Network [OSTI]

    Karen S. Martirosyan; Maxim Zyskin

    2012-12-17T23:59:59.000Z

    Aluminum-oxygen reaction is important in many highly energetic, high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a "double-layer" type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 C, our model predicts overall oxidation time scale in microseconds range, in agreement with experimental evidence.

  14. Reactive self-heating model of aluminum spherical nanoparticles

    E-Print Network [OSTI]

    Martirosyan, Karen S

    2012-01-01T23:59:59.000Z

    Aluminum-oxygen reaction is important in many highly energetic, high pressure generating systems. Recent experiments with nanostructured thermites suggest that oxidation of aluminum nanoparticles occurs in a few microseconds. Such rapid reaction cannot be explained by a conventional diffusion-based mechanism. We present a rapid oxidation model of a spherical aluminum nanoparticle, using Cabrera-Mott moving boundary mechanism, and taking self-heating into account. In our model, electric potential solves the nonlinear Poisson equation. In contrast with the Coulomb potential, a "double-layer" type solution for the potential and self-heating leads to enhanced oxidation rates. At maximal reaction temperature of 2000 C, our model predicts overall oxidation time scale in microseconds range, in agreement with experimental evidence.

  15. On numerical considerations for modeling reactive astrophysical shocks

    SciTech Connect (OSTI)

    Papatheodore, Thomas L.; Messer, O. E. Bronson, E-mail: tpapathe@utk.edu, E-mail: bronson@ornl.gov [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)

    2014-02-10T23:59:59.000Z

    Simulating detonations in astrophysical environments is often complicated by numerical approximations to shock structure. A common prescription to ensure correct detonation speeds and associated quantities is to prohibit burning inside the numerically broadened shock. We have performed a series of simulations to verify the efficacy of this approximation and to understand how resolution and dimensionality might affect its use. Our results show that in one dimension, prohibiting burning in the shock is important wherever the carbon burning length is not resolved, in keeping with the results of Fryxell et al. In two dimensions, we find that the prohibition of shock burning effectively inhibits the development of cellular structure for all but the most highly resolved cases. We discuss the possible impacts this outcome may have on sub-grid models and detonation propagation in models of Type Ia supernovae, including potential impacts on observables.

  16. Understanding the Subsurface Reactive Transport of Transuranic Contaminants at DOE Sites

    SciTech Connect (OSTI)

    Barnett, Mark O. [Auburn University] [Auburn University; Albrecht-Schmitt, Thomas E. [University of Notre Dame] [University of Notre Dame; Saiers, James E. [Yale University] [Yale University; Shuh, David K. [Lawrence Berkeley National Laboratory] [Lawrence Berkeley National Laboratory

    2013-12-20T23:59:59.000Z

    Our primary hypothesis is that actinides can interact with surfaces in fundamentally different ways than other metals, metalloids, and oxyanions and that this fundamental difference requires new approaches to studying and modeling transuranic sorption to minerals and geomedia. This project supports a key mission of the SBR program to develop sufficient scientific understanding such that DOE sites will be able to incorporate coupled physical, chemical, and biological processes into decision making for environmental management and long-term stewardship, while also supporting DOE’s commitment to education, training, and collaboration with DOE user facilities.

  17. On Numerical Considerations for Modeling Reactive Astrophysical Shocks

    SciTech Connect (OSTI)

    Papatheodore, Thomas L [ORNL] [ORNL; Messer, Bronson [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Simulating detonations in astrophysical environments is often complicated by numerical approximations to shock structure. A common prescription to ensure correct detonation speeds (and associated quantities) is to prohibit burning inside the numerically broadened shock (Fryxell et al. 1989). We have performed a series of simulations to verify the efficacy of this approximation and to understand how resolution and dimensionality might affect its use. Our results show that, in one dimension, prohibiting burning in the shock is important wherever the carbon burning length is not resolved, in keeping with the results of Fryxell et al. (1989). In two dimensions, we find that the prohibition of shock burning effectively inhibits the development of cellular structure for all but the most highly-resolved cases. We discuss the possible impacts this outcome may have on sub-grid models and detonation propagation in Type Ia supernovae.

  18. Documentation of TRU biological transport model (BIOTRAN)

    SciTech Connect (OSTI)

    Gallegos, A.F.; Garcia, B.J.; Sutton, C.M.

    1980-01-01T23:59:59.000Z

    Inclusive of Appendices, this document describes the purpose, rationale, construction, and operation of a biological transport model (BIOTRAN). This model is used to predict the flow of transuranic elements (TRU) through specified plant and animal environments using biomass as a vector. The appendices are: (A) Flows of moisture, biomass, and TRU; (B) Intermediate variables affecting flows; (C) Mnemonic equivalents (code) for variables; (D) Variable library (code); (E) BIOTRAN code (Fortran); (F) Plants simulated; (G) BIOTRAN code documentation; (H) Operating instructions for BIOTRAN code. The main text is presented with a specific format which uses a minimum of space, yet is adequate for tracking most relationships from their first appearance to their formulation in the code. Because relationships are treated individually in this manner, and rely heavily on Appendix material for understanding, it is advised that the reader familiarize himself with these materials before proceeding with the main text.

  19. SOLVING VERTICAL TRANSPORT AND CHEMISTRY IN AIR POLLUTION MODELS

    E-Print Network [OSTI]

    Botchev, Mike

    SOLVING VERTICAL TRANSPORT AND CHEMISTRY IN AIR POLLUTION MODELS P.J.F. BERKVENS #3; , M.A. BOTCHEV; transport-chemistry problems from air pollution modelling, standard ODE solvers are not feasible due causing large errors for such species. In the framework of an operational global air pollution model, we

  20. ON THE RECOVERY OF TRANSPORT PARAMETERS IN GROUNDWATER MODELLING

    E-Print Network [OSTI]

    Knowles, Ian W.

    ON THE RECOVERY OF TRANSPORT PARAMETERS IN GROUNDWATER MODELLING IAN KNOWLES AND AIMIN YAN. Introduction Saturated flow and single phase solute transport in confined ground- water systems are modelled one has to resort to indirect, or inverse, techniques to populate the model. In a groundwater system

  1. ON THE RECOVERY OF TRANSPORT PARAMETERS IN GROUNDWATER MODELLING

    E-Print Network [OSTI]

    Knowles, Ian W.

    ON THE RECOVERY OF TRANSPORT PARAMETERS IN GROUNDWATER MODELLING IAN KNOWLES AND AIMIN YAN. Introduction Saturated flow and single phase solute transport in confined ground­ water systems are modelled to resort to indirect, or inverse, techniques to populate the model. In a groundwater system one

  2. Water Transport in PEM Fuel Cells: Advanced Modeling, Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Testing and Design Optimization Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization Part of a 100 million fuel cell award...

  3. Water Transport in PEM Fuel Cells: Advanced Modeling, Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Testing, and Design Optimization Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing, and Design Optimization This presentation, which focuses on...

  4. An Example Uncertainty and Sensitivity Analysis for Reactive Transport at the Horonobe Site for Performance Assessment Calculations.

    SciTech Connect (OSTI)

    James, Scott; Cohan, Alexander [Sandia National Laboratories, Albuquerque, NM] [Sandia National Laboratories, Albuquerque, NM

    2005-08-01T23:59:59.000Z

    Given pre-existing Groundwater Modeling System (GMS) models of the Horonobe Underground Research Laboratory (URL) at both the regional and site scales, this work performs an example uncertainty analysis for performance assessment (PA) applications. After a general overview of uncertainty and sensitivity analysis techniques, the existing GMS site-scale model is converted to a PA model of the steady-state conditions expected after URL closure. This is done to examine the impact of uncertainty in site-specific data in conjunction with conceptual model uncertainty regarding the location of the Oomagari Fault. A heterogeneous stochastic model is developed and corresponding flow fields and particle tracks are calculated. In addition, a quantitative analysis of the ratio of dispersive to advective forces, the F-ratio, is performed for stochastic realizations of each conceptual model. Finally, a one-dimensional transport abstraction is modeled based on the particle path lengths and the materials through which each particle passes to yield breakthrough curves at the model boundary. All analyses indicate that accurate characterization of the Oomagari Fault with respect to both location and hydraulic conductivity is critical to PA calculations. This work defines and outlines typical uncertainty and sensitivity analysis procedures and demonstrates them with example PA calculations relevant to the Horonobe URL. Acknowledgement: This project was funded by Japan Nuclear Cycle Development Institute (JNC). This work was conducted jointly between Sandia National Laboratories (SNL) and JNC under a joint JNC/U.S. Department of Energy (DOE) work agreement. Performance assessment calculations were conducted and analyzed at SNL based on a preliminary model by Kashima, Quintessa, and JNC and include significant input from JNC to make sure the results are relevant for the Japanese nuclear waste program.

  5. Modeling the reactive inorganic solute distributions in the groundwater flow systems of the Hanford Site using inverse analytical modeling techniques

    E-Print Network [OSTI]

    Adamski, Mark Robert

    1993-01-01T23:59:59.000Z

    Inverse analytical techniques were used to model solute distributions and determine transport parameters for two flow systems in the Yakima Basalt subgroup at the Hanford Site in Washington state. Previous studies of these flow systems used...

  6. Integration of Groundwater Transport Models with Wireless Sensor Networks

    E-Print Network [OSTI]

    Han, Qi "Chee"

    Integration of Groundwater Transport Models with Wireless Sensor Networks Kevin Barnhart1 , I.jayasumana@colostate.edu, Fort Collins, CO, USA ABSTRACT Groundwater transport modeling is intended to aid in remediation be conceptualized in the WSN context. INTRODUCTION As groundwater contamination is an established problem with many

  7. Adaptive Methods for Modelling Transport Processes in Fractured Subsurface Systems

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    ­ discrete Galerkin method applying finite differences for the discretization in time and the StreamlineAdaptive Methods for Modelling Transport Processes in Fractured Subsurface Systems 3rd­adaptive methods for modelling transport processes in fractured rock. As a simplification, ideal tracers

  8. Review of petroleum transport network models and their applicability to a national refinery model

    SciTech Connect (OSTI)

    Hooker, J. N.

    1982-04-01T23:59:59.000Z

    This report examines four petroleum transport network models to determine whether parts of them can be incorporated into the transportation component of a national refinery model. Two questions in particular are addressed. (a) How do the models under examination represent the oil transport network, estimate link capacities, and calculate transport costs. (b) Are any of these network representations, capacity estimates, or cost functions suitable for inclusion in a linear programming model of oil refinery and primary distribution in the US. Only pipeline and waterway transport is discussed. The models examined are the Department of Energy's OILNET model, the Department of Transportation's Freight Energy Model, the Federal Energy Administration Petroleum Transportation Network Model, and an Oak Ridge National Laboratory oil pipeline energy model. Link capacity and cost functions are recommended for each transport mode. The coefficients of the recommended pipeline cost functions remain to be estimated.

  9. Reduced Fast Ion Transport Model For The Tokamak Transport Code TRANSP

    SciTech Connect (OSTI)

    Podesta,, Mario; Gorelenkova, Marina; White, Roscoe

    2014-02-28T23:59:59.000Z

    Fast ion transport models presently implemented in the tokamak transport code TRANSP [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, CEC Brussels, 1 , 19 (1980)] are not capturing important aspects of the physics associated with resonant transport caused by instabilities such as Toroidal Alfv#19;en Eigenmodes (TAEs). This work describes the implementation of a fast ion transport model consistent with the basic mechanisms of resonant mode-particle interaction. The model is formulated in terms of a probability distribution function for the particle's steps in phase space, which is consistent with the MonteCarlo approach used in TRANSP. The proposed model is based on the analysis of fast ion response to TAE modes through the ORBIT code [R. B. White et al., Phys. Fluids 27 , 2455 (1984)], but it can be generalized to higher frequency modes (e.g. Compressional and Global Alfv#19;en Eigenmodes) and to other numerical codes or theories.

  10. ab initio Electronic Transport Model with Explicit Solution to the Linearized Boltzmann Transport Equation

    E-Print Network [OSTI]

    Faghaninia, Alireza; Lo, Cynthia S

    2015-01-01T23:59:59.000Z

    Accurate models of carrier transport are essential for describing the electronic properties of semiconductor materials. To the best of our knowledge, the current models following the framework of the Boltzmann transport equation (BTE) either rely heavily on experimental data (i.e., semi-empirical), or utilize simplifying assumptions, such as the constant relaxation time approximation (BTE-cRTA). While these models offer valuable physical insights and accurate calculations of transport properties in some cases, they often lack sufficient accuracy -- particularly in capturing the correct trends with temperature and carrier concentration. We present here a general transport model for calculating low-field electrical drift mobility and Seebeck coefficient of n-type semiconductors, by explicitly considering all relevant physical phenomena (i.e. elastic and inelastic scattering mechanisms). We first rewrite expressions for the rates of elastic scattering mechanisms, in terms of ab initio properties, such as the ban...

  11. Modeling the impact of complexity on transportation

    E-Print Network [OSTI]

    Fernandez, Jose A. (Jose Antonio Fernandez Chavira)

    2012-01-01T23:59:59.000Z

    This thesis aimed to understand the drivers of total transportation costs during supply chain complexity events, in particular new product launches, in a fast moving consumer goods company in the United States. The research ...

  12. Scaling up and modeling for transport and flow

    E-Print Network [OSTI]

    Rogina, Mladen

    & modélisation des écoulements de fluides en milieux poreux DUBROVNIK, CROATIA 13-16 OCTOBER 2008 BOOK for Transport and Flow in Porous Media Dubrovnik, Croatia, 13-16 October 2008 Book of abstracts #12;Contents and Modeling for Transport and Flow in Porous Media, held at Dubrovnik, Croatia, 13­16 October 2008

  13. Keratin Dynamics: Modeling the Interplay between Turnover and Transport

    E-Print Network [OSTI]

    Stephanie Portet; Anotida Madzvamuse; Andy Chung; Rudolf E. Leube; Reinhard Windoffer

    2015-04-01T23:59:59.000Z

    Keratin are among the most abundant proteins in epithelial cells. Functions of the keratin network in cells are shaped by their dynamical organization. Using a collection of experimentally-driven mathematical models, different hypotheses for the turnover and transport of the keratin material in epithelial cells are tested. The interplay between turnover and transport and their effects on the keratin organization in cells are hence investigated by combining mathematical modeling and experimental data. Amongst the collection of mathematical models considered, a best model strongly supported by experimental data is identified. Fundamental to this approach is the fact that optimal parameter values associated with the best fit for each model are established. The best candidate among the best fits is characterized by the disassembly of the assembled keratin material in the perinuclear region and an active transport of the assembled keratin. Our study shows that an active transport of the assembled keratin is required to explain the experimentally observed keratin organization.

  14. Development of a scalable model for predicting arsenic transport coupled with oxidation and adsorption reactions

    E-Print Network [OSTI]

    Clement, Prabhakar

    modeling; Contaminant transport; Scaling; Numerical modeling 1. Introduction Management of groundwaterDevelopment of a scalable model for predicting arsenic transport coupled with oxidation is critical for predicting its transport dynamics in groundwater systems. We completed batch experiments

  15. Modeling spin magnetization transport in a spatially varying magnetic field

    E-Print Network [OSTI]

    Rico A. R. Picone; Joseph L. Garbini; John A. Sidles

    2014-08-13T23:59:59.000Z

    We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment. A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation.

  16. Deuteron-nucleus collisions in a multiphase transport model 

    E-Print Network [OSTI]

    Lin, ZW; Ko, Che Ming.

    2003-01-01T23:59:59.000Z

    Using a multiphase transport model, we study pseudorapidity distributions and transverse momentum spectra in deuteron-gold collisions at RHIC. We find that final-state partonic and hadronic interactions affect the transverse momentum spectrum...

  17. Subdiffusion and Superdiffusion in Lagrangian Stochastic Models of Oceanic Transport

    E-Print Network [OSTI]

    Kramer, Peter

    managable models are sought which capture the important phenomena of interest without needing to calculate of tracer transport associated to power-law regions of the La- grangian power spectrum. We focus on how well

  18. Modeling of Magnetic Nanoparticles Transport in Shale Reservoirs 

    E-Print Network [OSTI]

    An, Cheng

    2014-12-18T23:59:59.000Z

    of this technology for enhanced oil recovery, nano-scale sensors and subsurface mapping. Little work has been conducted to establish numerical models to investigate nanoparticle transport in reservoirs, and particularly much less for shale reservoirs. Unlike...

  19. Modeling of Magnetic Nanoparticles Transport in Shale Reservoirs

    E-Print Network [OSTI]

    An, Cheng

    2014-12-18T23:59:59.000Z

    of this technology for enhanced oil recovery, nano-scale sensors and subsurface mapping. Little work has been conducted to establish numerical models to investigate nanoparticle transport in reservoirs, and particularly much less for shale reservoirs. Unlike...

  20. Analytical model for flux saturation in sediment transport

    E-Print Network [OSTI]

    Pähtz, T; Kok, J F; Herrmann, H J

    2014-01-01T23:59:59.000Z

    The transport of sediment by a fluid along the surface is responsible for dune formation, dust entrainment and for a rich diversity of patterns on the bottom of oceans, rivers, and planetary surfaces. Most previous models of sediment transport have focused on the equilibrium (or saturated) particle flux. However, the morphodynamics of sediment landscapes emerging due to surface transport of sediment is controlled by situations out-of-equilibrium. In particular, it is controlled by the saturation length characterizing the distance it takes for the particle flux to reach a new equilibrium after a change in flow conditions. The saturation of mass density of particles entrained into transport and the relaxation of particle and fluid velocities constitute the main relevant relaxation mechanisms leading to saturation of the sediment flux. Here we present a theoretical model for sediment transport which, for the first time, accounts for both these relaxation mechanisms and for the different types of sediment entrain...

  1. Modelling Ammonium Transporters in Arbuscular Mycorrhiza Symbiosis

    E-Print Network [OSTI]

    Troina, Angelo

    transporter which exists in plants, viz. LjAMT1;1, our simulations support an hypothesis about why LjAMT2 potential as a natural plant This research is founded by the BioBITs Project (Converging Technologies 2007 to play a fundamen- tal role for plant mineral acquisition, which takes place in the arbuscular mycorrhiza

  2. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 1

    SciTech Connect (OSTI)

    NONE

    1998-01-01T23:59:59.000Z

    This volume contains input data and parameters used in the model of the transportation sector of the National Energy Modeling System. The list of Transportation Sector Model variables includes parameters for the following: Light duty vehicle modules (fuel economy, regional sales, alternative fuel vehicles); Light duty vehicle stock modules; Light duty vehicle fleet module; Air travel module (demand model and fleet efficiency model); Freight transport module; Miscellaneous energy demand module; and Transportation emissions module. Also included in these appendices are: Light duty vehicle market classes; Maximum light duty vehicle market penetration parameters; Aircraft fleet efficiency model adjustment factors; and List of expected aircraft technology improvements.

  3. Methods for modeling impact-induced reactivity changes in small reactors.

    SciTech Connect (OSTI)

    Tallman, Tyler N.; Radel, Tracy E.; Smith, Jeffrey A.; Villa, Daniel L.; Smith, Brandon M. (U. of Wisconsin, Madison, WI); Radel, Ross F.; Lipinski, Ronald J.; Wilson, Paul Philip Hood (U. of Wisconsin, Madison, WI)

    2010-10-01T23:59:59.000Z

    This paper describes techniques for determining impact deformation and the subsequent reactivity change for a space reactor impacting the ground following a potential launch accident or for large fuel bundles in a shipping container following an accident. This technique could be used to determine the margin of subcriticality for such potential accidents. Specifically, the approach couples a finite element continuum mechanics model (Pronto3D or Presto) with a neutronics code (MCNP). DAGMC, developed at the University of Wisconsin-Madison, is used to enable MCNP geometric queries to be performed using Pronto3D output. This paper summarizes what has been done historically for reactor launch analysis, describes the impact criticality analysis methodology, and presents preliminary results using representative reactor designs.

  4. Interactive coastal oil spill transport model

    E-Print Network [OSTI]

    Thalasila, Nanda K.

    1992-01-01T23:59:59.000Z

    and in time contaminate large areas. Knowing the behavior of an oil slick after it has been inadvirently released to the ocean surface may be of great practical value. It will permit an assessment of the potential damage to aquatic life and shoreline... Function of Time 20 Longshore Current Nomograph 31 Oil Slick Transport Vectors by Areal Extent (adapted from Keith, et al, 1977)s 32 Program Structure for Program OILSPILL Program Structure for Subroutine DATAENT 37 37 Program Structure...

  5. An Ab Initio Model of Electron Transport in Hematite (a-Fe2O3...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    An Ab Initio Model of Electron Transport in Hematite (a-Fe2O3) Basal Planes. An Ab Initio Model of Electron Transport in Hematite (a-Fe2O3) Basal Planes. Abstract: Transport of...

  6. Langevin and Fokker-Planck analyses of inhibited molecular passing processes controlling transport and reactivity in nanoporous materials

    SciTech Connect (OSTI)

    Wang, Chi-Jen [Ames Laboratory; Ackerman, David M. [Ames Laboratory; Slowing, Igor I. [Ames Laboratory; Evans, James W. [Ames Laboratory

    2014-07-14T23:59:59.000Z

    Inhibited passing of reactant and product molecules within the linear pores of nanoporous catalytic materials strongly reduces reactivity. The dependence of the passing propensity P on pore radius R is analyzed utilizing Langevin dynamics to account for solvent effects. We find that P?(R?Rc)?, where passing is sterically blocked for R?Rc, with ? below the transition state theory value. Deeper insight comes from analysis of the corresponding high-dimensional Fokker-Planck equation, which facilitates an effective small-P approximation, and dimensional reduction enabling utilization of conformal mapping ideas. We analyze passing for spherical molecules and also assess the effect of rotational degrees of freedom for elongated molecules.

  7. TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions

    SciTech Connect (OSTI)

    Xu, T.; Spycher, N.; Sonnenthal, E.; Zhang, G.; Zheng, L.; Pruess, K.

    2010-08-01T23:59:59.000Z

    TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media, and was developed by introducing reactive chemistry into the multiphase fluid and heat flow simulator TOUGH2 V2. The first version of TOUGHREACT was released to the public through the U.S. Department of Energy's Energy Science and Technology Software Center (ESTSC) in August 2004. It is among the most frequently requested of ESTSC's codes. The code has been widely used for studies in CO{sub 2} geological sequestration, nuclear waste isolation, geothermal energy development, environmental remediation, and increasingly for petroleum applications. Over the past several years, many new capabilities have been developed, which were incorporated into Version 2 of TOUGHREACT. Major additions and improvements in Version 2 are discussed here, and two application examples are presented: (1) long-term fate of injected CO{sub 2} in a storage reservoir and (2) biogeochemical cycling of metals in mining-impacted lake sediments.

  8. Tungsten Transport in JET H-mode Plasmas in Hybrid Scenario, Experimental Observations and Modelling

    E-Print Network [OSTI]

    Tungsten Transport in JET H-mode Plasmas in Hybrid Scenario, Experimental Observations and Modelling

  9. Impact of transport model errors on the global and regional methane emissions estimated by inverse modelling

    E-Print Network [OSTI]

    Locatelli, R.

    A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model ...

  10. Toward a Process-Based Molecular Model of SiC Membranes. 1. Development of a Reactive Force Field

    E-Print Network [OSTI]

    Goddard III, William A.

    Toward a Process-Based Molecular Model of SiC Membranes. 1. Development of a Reactive Force Field Angeles, California 90089-1211, United States Computational Chemistry Group, School of Chemistry be compared with experimental data. Good agreement is found between the data and the results of the MD

  11. Rate-Based Modeling of Reactive Absorption of CO2 and H2S into Aqueous Methyldiethanolamine

    E-Print Network [OSTI]

    Rochelle, Gary T.

    Rate-Based Modeling of Reactive Absorption of CO2 and H2S into Aqueous Methyldiethanolamine Manuel in the liquid phase. This framework was applied to the selective absorption of H2S from fuel gas containing CO2 primarily by physical absorption. Gas-film resistance is never significant for CO2 absorption. For H2S

  12. Transport Phenomena in Polymer Electrolyte Membranes I. Modeling Framework

    E-Print Network [OSTI]

    Struchtrup, Henning

    and optimization of fuel cells in a design and development environment. Kreuer et al.19 recently presented of ongoing efforts to develop more comprehensive compu- tational fuel cell model14-18 that allow analysis of the fundamental transport mechanisms. In the context of multidimensional fuel cell modeling, practical

  13. 155: Numerical Models of Groundwater Flow and Transport

    E-Print Network [OSTI]

    Sorek, Shaul

    155: Numerical Models of Groundwater Flow and Transport EKKEHARD HOLZBECHER1 AND SHAUL SOREK2 1. #12;2402 GROUNDWATER Calibration as a task cannot be separated from the other tasks. Inverse modeling of the Negev, J. Blaustein Institutes for Desert Research, Sede Boker, Israel The article gives an introduction

  14. Coupled modeling of groundwater flow solute transport, chemical reactions and microbial processes in the 'SP' island

    SciTech Connect (OSTI)

    Samper, Javier; Molinero, Jorg; Changbing, Yang; Zhang, Guoxiang

    2003-12-01T23:59:59.000Z

    The Redox Zone Experiment was carried out at the Aespoe HRL in order to study the redox behavior and the hydrochemistry of an isolated vertical fracture zone disturbed by the excavation of an access tunnel. Overall results and interpretation of the Redox Zone Project were reported by /Banwart et al, 1995/. Later, /Banwart et al, 1999/ presented a summary of the hydrochemistry of the Redox Zone Experiment. Coupled groundwater flow and reactive transport models of this experiment were carried out by /Molinero, 2000/ who proposed a revised conceptual model for the hydrogeology of the Redox Zone Experiment which could explain simultaneously measured drawdown and salinity data. The numerical model was found useful to understand the natural system. Several conclusions were drawn about the redox conditions of recharge waters, cation exchange capacity of the fracture zone and the role of mineral phases such as pyrite, calcite, hematite and goethite. This model could reproduce the measured trends of dissolved species, except for bicarbonate and sulfate which are affected by microbially-mediated processes. In order to explore the role of microbial processes, a coupled numerical model has been constructed which accounts for water flow, reactive transport and microbial processes. The results of this model is presented in this report. This model accounts for groundwater flow and reactive transport in a manner similar to that of /Molinero, 2000/ and extends the preliminary microbial model of /Zhang, 2001/ by accounting for microbially-driven organic matter fermentation and organic matter oxidation. This updated microbial model considers simultaneously the fermentation of particulate organic matter by yeast and the oxidation of dissolved organic matter, a product of fermentation. Dissolved organic matter is produced by yeast and serves also as a substrate for iron-reducing bacteria. Model results reproduce the observed increase in bicarbonate and sulfate concentration, thus adding additional evidence for the possibility of organic matter oxidation as the main source of bicarbonate. Model results indicate that pH and Eh are relatively stable. The dissolution-precipitation trends of hematite, pyrite and calcite also coincide with those indicated by the conceptual model. A thorough sensitivity analysis has been performed for the most relevant microbial parameters as well as for initial and boundary POC and DOC concentrations. The results of such analysis indicate that computed concentrations of bicarbonate, sulfate and DOC are sensitive to most of the microbial parameters, including specific growth rates, half-saturation constants, proportionality coefficients and yield coefficients. Model results, however, are less sensitive to the yield coefficient of DOC to iron-reducer bacteria. The sensitivity analysis indicates that changes in fermentation microbial parameters affect the growth of the iron-reducer, thus confirming the interconnection of both microbial processes. Computed concentrations of bicarbonate and sulfate are found to be sensitive to changes in the initial concentration of POC and the boundary concentration of DOC, but they lack sensitivity to the initial concentration of DOC and the boundary concentration of POC. The explanation for such result is related to the fact that POC has a low mobility due to its large molecular weight. DOC, however, can migrate downwards. Although a coupled hydro-bio-geochemical 1-D model can reproduce the observed ''unexpected'' increase of concentrations of bicarbonate and sulfate at a depth of 70 m, further modeling work is required in order to obtain a similar conclusion under the more realistic two dimensional conditions of the fracture zone.

  15. Modeling of plasma-target interaction during reactive magnetron sputtering of TiN

    SciTech Connect (OSTI)

    Moeller, W.; Guettler, D. [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)

    2007-11-01T23:59:59.000Z

    The nitrogen incorporation at the target during reactive magnetron sputtering of TiN is described by a simple stationary global model of the magnetron plasma, in combination with an analytical two-layer stationary surface model or dynamic collisional computer simulation (TRIDYN) of the surface processes. Results are shown for different nitrogen gas additions in Ar/N{sub 2} and Xe/N{sub 2} gas mixtures at a total pressure of 0.3 Pa and a magnetron current of 0.3 A. The nitrogen incorporation predicted by the analytical model is significantly less than obtained from computer simulation. The computer simulation yields nitrogen depth profiles which extend to about 2.5 nm, exhibiting a quasirectangular shape in case of stoichiometric saturation with an integrated nitrogen areal density of {approx}1.25x10{sup 16} N/cm{sup 2}. The stationary-state nitrogen incorporation results from the balance of surface adsorption in connection with recoil implantation, direct ion implantation, and resputtering. The most relevant species are nitrogen gas molecules for adsorption, molecular nitrogen ions for implantation, and inert gas ions for recoil implantation and sputtering. The model results are in good agreement with experiment provided that nonzero sticking of nitrogen gas molecules is assumed on the unsaturated surface. The analytical surface model is preferable, which favors the picture of a continuous transition to bulk and surface saturation rather than discrete local saturation which is inherent in TRIDYN. Also the relative nitrogen incorporation for Xe/N{sub 2} versus Ar/N{sub 2} gas mixtures is well described.

  16. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect (OSTI)

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20T23:59:59.000Z

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  17. Mitochondrial reactive oxygen species and cancer

    E-Print Network [OSTI]

    Chandel, Navdeep S

    Mitochondria produce reactive oxygen species (mROS) as a natural by-product of electron transport chain activity. While initial studies focused on the damaging effects of reactive oxygen species, a recent paradigm shift ...

  18. Mass-Conserved Phase Field Models for Binary Fluids

    E-Print Network [OSTI]

    2012-07-13T23:59:59.000Z

    The commonly used incompressible phase field models for non-reactive, bi- nary fluids, in which the Cahn-Hilliard equation is used for the transport of phase.

  19. Allocating city space to multiple transportation modes: A new modeling approach consistent with the physics of transport

    E-Print Network [OSTI]

    Kammen, Daniel M.

    Allocating city space to multiple transportation modes: A new modeling approach consistent with the physics of transport Eric J. Gonzales, Nikolas Geroliminis, Michael J. Cassidy and Carlos F. Daganzo WORKING PAPER UCB-ITS-VWP-2008-1 March 2008 #12;Allocating city space to multiple transportation modes

  20. A Stochastic Model of Transport in Three-Dimensional Porous Media1

    E-Print Network [OSTI]

    Boyer, Edmond

    Lee2 Modeling of solute transport remains a key issue in the area of groundwater contamination transport, non-Fickian dispersion, random walk, stochastic processes. INTRODUCTION Solute transport modelA Stochastic Model of Transport in Three-Dimensional Porous Media1 Cyril Fleurant2 and Jan van der

  1. Transportation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transportation Home Agenda Awards Exhibitors Lodging Posters Registration Transportation Workshops Contact Us User Meeting Archives Users' Executive Committee Getting to Berkeley...

  2. Transportation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transportation Print Home Agenda Awards Exhibitors Lodging Posters Registration Transportation Workshops Contact Us User Meeting Archives Users' Executive Committee Getting to...

  3. Dissipative particle dynamics model for colloid transport in porous media

    SciTech Connect (OSTI)

    Pan, Wenxiao; Tartakovsky, Alexandre M.

    2013-08-01T23:59:59.000Z

    We present that the transport of colloidal particles in porous media can be effectively modeled with a new formulation of dissipative particle dynamics, which augments standard DPD with non-central dissipative shear forces between particles while preserving angular momentum. Our previous studies have demonstrated that the new formulation is able to capture accurately the drag forces as well as the drag torques on colloidal particles that result from the hydrodynamic retardation e?ect. In the present work, we use the new formulation to study the contact e?ciency in colloid ?ltration in saturated porous media. Note that the present model include all transport mechanisms simultaneously, including gravitational sedimentation, interception and Brownian di?usion. Our results of contact e?ciency show a good agreement with the predictions of the correlation equation proposed by Tufenkji and EliMelech, which also incorporate all transport mechanisms simultaneously without the additivity assumption.

  4. Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model Output

    E-Print Network [OSTI]

    Shi, Tao

    Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model of aerosol optical depth across mainland Southeast Asia. We include a cross validation study to assess

  5. Global transportation cost modeling for long-range planning

    SciTech Connect (OSTI)

    Pope, R.B.; Michelhaugh, R.D.; Singley, P.T. [Oak Ridge National Lab., TN (United States); Lester, P.B. [Dept. of Energy, Oak Ridge, TN (United States)

    1998-02-01T23:59:59.000Z

    The US Department of Energy (DOE) is preparing to perform significant remediation activities of the sites for which it is responsible. To accomplish this, it is preparing a corporate global plan focused on activities over the next decade. Significant in these planned activities is the transportation of the waste arising from the remediation. The costs of this transportation are expected to be large. To support the initial assessment of the plan, a cost estimating model was developed, peer-reviewed against other available packaging and transportation cost data, and applied to a significant number of shipping campaigns of radioactive waste. This cost estimating model, known as the Ten-year Plan Transportation Cost Model (TEPTRAM), can be used to model radioactive material shipments between DOE sites or from DOE sites to non-DOE destinations. The model considers the costs for (a) recovering and processing of the wastes, (b)packaging the wastes for transport, and (c) the carriage of the waste. It also provides a rough order of magnitude estimate of labor costs associated with preparing and undertaking the shipments. At the user`s direction, the model can also consider the cost of DOE`s interactions with its external stakeholders (e.g., state and local governments and tribal entities) and the cost associated with tracking and communicating with the shipments. By considering all of these sources of costs, it provides a mechanism for assessing and comparing the costs of various waste processing and shipping campaign alternatives to help guide decision-making. Recent analyses of specific planned shipments of transuranic (TRU) waste which consider alternative packaging options are described. These analyses show that options are available for significantly reducing total costs while still satisfying regulatory requirements.

  6. CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER

    E-Print Network [OSTI]

    Boyer, Edmond

    , 60550 Verneuil-en-Halatte - France, fabrice.quiot@ineris.fr 2. ENVIROS, Spain S.L., Passeig de Rubi 29-31, 08197 Valldoreix - Spain, sjordana@enviros.biz 3. ANTEA, Direction Technique, 3 avenue Claude Guillemin in order to bring a better and common practice of the use of transport models concerning various pollutants

  7. Steady states for Streater's energy-transport models

    E-Print Network [OSTI]

    Esteban, Maria J.

    Steady states for Streater's energy-transport models of self/4, 50-384 Wroc_law, Poland Piotr.Biler@math.uni.wroc.pl, 2Ceremade Matematyki, Politechnika Zielonog'orska, ul. Podg'orna 50, 65-246 Zielona G'ora, Poland

  8. Microbial controls on contaminant metal transport in porous media 

    E-Print Network [OSTI]

    Kapetas, Leon

    2011-11-24T23:59:59.000Z

    and IOCS materials were determined through batch adsorption experiments, providing a mechanistic explanation of the adsorption process. Reactive transport models incorporating kinetics and surface complexation are developed to describe zinc movement through...

  9. Multiscale modeling for fluid transport in nanosystems.

    SciTech Connect (OSTI)

    Lee, Jonathan W.; Jones, Reese E.; Mandadapu, Kranthi Kiran; Templeton, Jeremy Alan; Zimmerman, Jonathan A.

    2013-09-01T23:59:59.000Z

    Atomistic-scale behavior drives performance in many micro- and nano-fluidic systems, such as mircrofludic mixers and electrical energy storage devices. Bringing this information into the traditionally continuum models used for engineering analysis has proved challenging. This work describes one such approach to address this issue by developing atomistic-to-continuum multi scale and multi physics methods to enable molecular dynamics (MD) representations of atoms to incorporated into continuum simulations. Coupling is achieved by imposing constraints based on fluxes of conserved quantities between the two regions described by one of these models. The impact of electric fields and surface charges are also critical, hence, methodologies to extend finite-element (FE) MD electric field solvers have been derived to account for these effects. Finally, the continuum description can have inconsistencies with the coarse-grained MD dynamics, so FE equations based on MD statistics were derived to facilitate the multi scale coupling. Examples are shown relevant to nanofluidic systems, such as pore flow, Couette flow, and electric double layer.

  10. Comb models for transport along spiny dendrites

    E-Print Network [OSTI]

    Méndez, V

    2015-01-01T23:59:59.000Z

    This chapter is a contribution in the "Handbook of Applications of Chaos Theory" ed. by Prof. Christos H Skiadas. The chapter is organized as follows. First we study the statistical properties of combs and explain how to reduce the effect of teeth on the movement along the backbone as a waiting time distribution between consecutive jumps. Second, we justify an employment of a comb-like structure as a paradigm for further exploration of a spiny dendrite. In particular, we show how a comb-like structure can sustain the phenomenon of the anomalous diffusion, reaction-diffusion and L\\'evy walks. Finally, we illustrate how the same models can be also useful to deal with the mechanism of ta translocation wave / translocation waves of CaMKII and its propagation failure. We also present a brief introduction to the fractional integro-differentiation in appendix at the end of the chapter.

  11. LOCALISATION OF A REACTIVE TRANSPORT ZONE IN A SATU-RATED KARSTIC CONDUIT DEDUICED FROM NATURAL AND ARTI-

    E-Print Network [OSTI]

    Boyer, Edmond

    : For groundwater resources managers, flow modeling is a useful tool to investigate sustainable scenarios of water the diameter of the conduit zone by an estimated 40 cm in 100 years. INTRODUCTION For groundwater resource managers, groundwater flow modeling is an essential tool for investigating proposed sustainable scenarios

  12. Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

    SciTech Connect (OSTI)

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.

    1982-12-01T23:59:59.000Z

    SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides (/sup 137/Cs, /sup 90/Sr, /sup 239/ /sup 240/Pu, and /sup 3/H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay.

  13. Model documentation report: Transportation sector model of the National Energy Modeling System

    SciTech Connect (OSTI)

    Not Available

    1994-03-01T23:59:59.000Z

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. This document serves three purposes. First, it is a reference document providing a detailed description of TRAN for model analysts, users, and the public. Second, this report meets the legal requirements of the Energy Information Administration (EIA) to provide adequate documentation in support of its statistical and forecast reports (Public Law 93-275, 57(b)(1)). Third, it permits continuity in model development by providing documentation from which energy analysts can undertake model enhancements, data updates, and parameter refinements.

  14. Anisotropic Elastic Resonance Scattering model for the Neutron Transport equation

    SciTech Connect (OSTI)

    Mohamed Ouisloumen; Abderrafi M. Ougouag; Shadi Z. Ghrayeb

    2014-11-24T23:59:59.000Z

    The resonance scattering transfer cross-section has been reformulated to account for anisotropic scattering in the center-of-mass of the neutron-nucleus system. The main innovation over previous implementations is the relaxation of the ubiquitous assumption of isotropic scattering in the center-of-mass and the actual effective use of scattering angle distributions from evaluated nuclear data files in the computation of the angular moments of the resonant scattering kernels. The formulas for the high order anisotropic moments in the laboratory system are also derived. A multi-group numerical formulation is derived and implemented into a module incorporated within the NJOY nuclear data processing code. An ultra-fine energy mesh cross section library was generated using these new theoretical models and then was used for fuel assembly calculations with the PARAGON lattice physics code. The results obtained indicate a strong effect of this new model on reactivity, multi-group fluxes and isotopic inventory during depletion.

  15. COMPARISON OF RF CAVITY TRANSPORT MODELS FOR BBU SIMULATIONS

    SciTech Connect (OSTI)

    Ilkyoung Shin,Byung Yunn,Todd Satogata,Shahid Ahmed

    2011-03-01T23:59:59.000Z

    The transverse focusing effect in RF cavities plays a considerable role in beam dynamics for low-energy beamline sections and can contribute to beam breakup (BBU) instability. The purpose of this analysis is to examine RF cavity models in simulation codes which will be used for BBU experiments at Jefferson Lab and improve BBU simulation results. We review two RF cavity models in the simulation codes elegant and TDBBU (a BBU simulation code developed at Jefferson Lab). elegant can include the Rosenzweig-Serafini (R-S) model for the RF focusing effect. Whereas TDBBU uses a model from the code TRANSPORT which considers the adiabatic damping effect, but not the RF focusing effect. Quantitative comparisons are discussed for the CEBAF beamline. We also compare the R-S model with the results from numerical simulations for a CEBAF-type 5-cell superconducting cavity to validate the use of the R-S model as an improved low-energy RF cavity transport model in TDBBU. We have implemented the R-S model in TDBBU. It will improve BBU simulation results to be more matched with analytic calculations and experimental results.

  16. Transportation

    E-Print Network [OSTI]

    Vinson, Steve

    2013-01-01T23:59:59.000Z

    Transportation in ancient Egypt entailed the use of boats2007 Land transport in Roman Egypt: A study of economics andDieter 1991 Building in Egypt: Pharaonic stone masonry. New

  17. Uncertainty in the reactive transport model response to an alkaline perturbation in a clay formation

    E-Print Network [OSTI]

    Burnol, A.; Blanc, P.; Xu, T.; Spycher, N.; Gaucher, E.C.

    2006-01-01T23:59:59.000Z

    degradation of a concrete/clay interface, in Migration'05 -an alkaline plume in a clay barrier, Applied Geochemistry,AN ALKALINE PERTURBATION IN A CLAY FORMATION A. Burnol*, P.

  18. Multiphase flow and multicomponent reactive transport model of the ventilation experiment in Opalinus clay

    E-Print Network [OSTI]

    Zheng, L.

    2010-01-01T23:59:59.000Z

    experiment in Opalinus Clay for the management ofconductivity of the Opalinus clay at a regional scale:1953. Adsorption studies on clay minerals. II. A formulation

  19. A model for transport and agglomeration of particles in reactive ion etching plasma reactors

    E-Print Network [OSTI]

    Kushner, Mark

    drag, electrostatic, neutral drag, thermophoretic, gravitational, and self-diffusion. Ion drag forces

  20. Geophysical monitoring and reactive transport modeling of ureolytically-driven calcium carbonate precipitation

    E-Print Network [OSTI]

    Wu, Y.

    2012-01-01T23:59:59.000Z

    F. S. ; Smith, R. W. , Calcium Carbonate Precipitation byF. , Microbially Mediated Calcium Carbonate Precipitation:through mixing of calcium and carbonate solutions in a glass

  1. Multicomponent reactive transport modeling at the Ratones uranium mine, Cceres (Spain)

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    abandonadas puede dar lugar a impactos importantes en la calidad del agua subterránea. Por lo tanto, predecir Ratones es una mina de uranio subterránea, que fue abandonada e inundada en 1974. Gracias al ambiente

  2. Bioclogging and Permeability Alteration by L. mesenteroides in a Sandstone Reservoir: A Reactive Transport Modeling Study

    E-Print Network [OSTI]

    Hubbard, Susan

    -Enhanced- Hydrocarbon-Recovery (MEHR).2 During water flooding in secondary recovery, hydrocarbons in highly permeable systems to favorable performance conditions. Applications may include microbial-enhanced-hydrocarbon-recovery

  3. A new mobileimmobile model for reactive solute transport with scaledependent dispersion

    E-Print Network [OSTI]

    Zhan, Hongbin

    Gao,1,2 Hongbin Zhan,3 Shaoyuan Feng,2 Bojie Fu,1 Ying Ma,2 and Guanhua Huang2,4 Received 28 September

  4. Reactive Transport Modeling of Natural Attenuation in Stormwater Bioretention Cells and Under Land Application of Wastewater

    E-Print Network [OSTI]

    Zhang, Jingqiu

    2014-04-29T23:59:59.000Z

    application. Due to less water and chemical input, climate patterns may lead to better removal of heavy metals. For land application of Oil and Gas Exploration and Production wastewater, five scenarios were developed to study the impact of chloride, salts...

  5. Coupled Model for Heat and Water Transport in a High Level Waste...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Model for Heat and Water Transport in a High Level Waste Repository in Salt Coupled Model for Heat and Water Transport in a High Level Waste Repository in Salt This report...

  6. Modeling of heavy metal transport in a contaminated soil

    SciTech Connect (OSTI)

    Cernik, M.; Federer, P.; Borkovec, M.; Sticher, H. [Inst. of Terrestrial Ecology, Schlieren (Switzerland)

    1994-11-01T23:59:59.000Z

    Observed depth profiles in soils polluted by Zn and Cu that originate from a metal smelter are quantitatively interpreted by combining the production history of the smelter with established transport models. Using independent laboratory and field data, we were able to calculate the present depth profiles semiquantitatively by applying the pure convection model without parameter fitting. The agreement of the calculated depth profiles with the experimental data can be improved by including dispersion effects in the convection-dispersion model or the stochastic convection model. For the latter model, the depth profiles were calculated analytically. These models were used to calculate the expected depth profiles in the future and to judge possible remediation strategies. 48 refs., 12 figs., 1 tab.

  7. Advancements in the ADAPT Photospheric Flux Transport Model

    E-Print Network [OSTI]

    Kyle S. Hickmann; Humberto C. Godinez; Carl J. Henney; C. Nick Arge

    2015-04-08T23:59:59.000Z

    Global maps of the solar photospheric magnetic flux are fundamental drivers for simulations of the corona and solar wind and therefore are important predictors of geoeffective events. However, observations of the solar photosphere are only made intermittently over approximately half of the solar surface. The Air Force Data Assimilative Photospheric Flux Transport (ADAPT) model uses localized ensemble Kalman filtering techniques to adjust a set of photospheric simulations to agree with the available observations. At the same time, this information is propagated to areas of the simulation that have not been observed. ADAPT implements a local ensemble transform Kalman filter (LETKF) to accomplish data assimilation, allowing the covariance structure of the flux transport model to influence assimilation of photosphere observations while eliminating spurious correlations between ensemble members arising from a limited ensemble size. We give a detailed account of the implementation of the LETKF into ADAPT. Advantages of the LETKF scheme over previously implemented assimilation methods are highlighted.

  8. Multiphase transport model for heavy ion collisions at RHIC

    E-Print Network [OSTI]

    Zi-wei Lin; Subrata Pal; C. M. Ko; Bao-An Li; Bin Zhang

    2001-05-18T23:59:59.000Z

    Using a multiphase transport model (AMPT) with both partonic and hadronic interactions, we study the multiplicity and transverse momentum distributions of charged particles such as pions, kaons and protons in central Au+Au collisions at RHIC energies. Effects due to nuclear shadowing and jet quenching on these observables are also studied. We further show preliminary results on the production of multistrange baryons from the strangeness-exchange reactions during the hadronic stage of heavy ion collisions.

  9. Modeling of contaminant transport in underground coal gasification

    SciTech Connect (OSTI)

    Lanhe Yang; Xing Zhang [China University of Mining and Technology, Xuzhou (China). College of Resources and Geosciences

    2009-01-15T23:59:59.000Z

    In order to study and discuss the impact of contaminants produced from underground coal gasification on groundwater, a coupled seepage-thermodynamics-transport model for underground gasification was developed on the basis of mass and energy conservation and pollutant-transport mechanisms, the mathematical model was solved by the upstream weighted multisell balance method, and the model was calibrated and verified against the experimental site data. The experiment showed that because of the effects of temperature on the surrounding rock of the gasification panel the measured pore-water-pressure was higher than the simulated one; except for in the high temperature zone where the simulation errors of temperature, pore water pressure, and contaminant concentration were relatively high, the simulation values of the overall gasification panel were well fitted with the measured values. As the gasification experiment progressed, the influence range of temperature field expanded, the gradient of groundwater pressure decreased, and the migration velocity of pollutant increased. Eleven months and twenty months after the test, the differences between maximum and minimum water pressure were 2.4 and 1.8 MPa, respectively, and the migration velocities of contaminants were 0.24-0.38 m/d and 0.27-0.46 m/d, respectively. It was concluded that the numerical simulation of the transport process for pollutants from underground coal gasification was valid. 42 refs., 13 figs., 1 tab.

  10. Modeling of transport phenomena in tokamak plasmas with neural networks

    SciTech Connect (OSTI)

    Meneghini, O., E-mail: meneghini@fusion.gat.com [Oak Ridge Associated Universities, 120 Badger Ave, Oak Ridge, Tennessee 37830 (United States); Luna, C. J. [Arizona State University, 411 N. Central Ave, Phoenix, Arizona 85004 (United States); Smith, S. P.; Lao, L. L. [General Atomics, San Diego, California 92186-5608 (United States)

    2014-06-15T23:59:59.000Z

    A new transport model that uses neural networks (NNs) to yield electron and ion heat flux profiles has been developed. Given a set of local dimensionless plasma parameters similar to the ones that the highest fidelity models use, the NN model is able to efficiently and accurately predict the ion and electron heat transport profiles. As a benchmark, a NN was built, trained, and tested on data from the 2012 and 2013 DIII-D experimental campaigns. It is found that NN can capture the experimental behavior over the majority of the plasma radius and across a broad range of plasma regimes. Although each radial location is calculated independently from the others, the heat flux profiles are smooth, suggesting that the solution found by the NN is a smooth function of the local input parameters. This result supports the evidence of a well-defined, non-stochastic relationship between the input parameters and the experimentally measured transport fluxes. The numerical efficiency of this method, requiring only a few CPU-?s per data point, makes it ideal for scenario development simulations and real-time plasma control.

  11. Pajarito Plateau Groundwater Flow and Transport Modeling Process-Level and Systems Models of Groundwater Flow and

    E-Print Network [OSTI]

    Lu, Zhiming

    Pajarito Plateau Groundwater Flow and Transport Modeling 1 Process-Level and Systems Models of Groundwater Flow and Transport Beneath the Pajarito Plateau: Migration of High Explosives from Technical Area Groundwater Modeling Project Systems Model Vadose Zone Model Regional Aquifer Model #12;Pajarito Plateau

  12. Building 235-F Goldsim Fate And Transport Model

    SciTech Connect (OSTI)

    Taylor, G. A.; Phifer, M. A.

    2012-09-14T23:59:59.000Z

    Savannah River National Laboratory (SRNL) personnel, at the request of Area Completion Projects (ACP), evaluated In-Situ Disposal (ISD) alternatives that are under consideration for deactivation and decommissioning (D&D) of Building 235-F and the Building 294-2F Sand Filter. SRNL personnel developed and used a GoldSim fate and transport model, which is consistent with Musall 2012, to evaluate relative to groundwater protection, ISD alternatives that involve either source removal and/or the grouting of portions or all of 235-F. This evaluation was conducted through the development and use of a Building 235-F GoldSim fate and transport model. The model simulates contaminant release from four 235-F process areas and the 294-2F Sand Filter. In addition, it simulates the fate and transport through the vadose zone, the Upper Three Runs (UTR) aquifer, and the Upper Three Runs (UTR) creek. The model is designed as a stochastic model, and as such it can provide both deterministic and stochastic (probabilistic) results. The results show that the median radium activity concentrations exceed the 5 ?Ci/L radium MCL at the edge of the building for all ISD alternatives after 10,000 years, except those with a sufficient amount of inventory removed. A very interesting result was that grouting was shown to basically have minimal effect on the radium activity concentration. During the first 1,000 years grouting may have some small positive benefit relative to radium, however after that it may have a slightly deleterious effect. The Pb-210 results, relative to its 0.06 ?Ci/L PRG, are essentially identical to the radium results, but the Pb-210 results exhibit a lesser degree of exceedance. In summary, some level of inventory removal will be required to ensure that groundwater standards are met.

  13. Transportation Sector Model of the National Energy Modeling System. Volume 1

    SciTech Connect (OSTI)

    NONE

    1998-01-01T23:59:59.000Z

    This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Transportation Model (TRAN). The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated by the model. The NEMS Transportation Model comprises a series of semi-independent models which address different aspects of the transportation sector. The primary purpose of this model is to provide mid-term forecasts of transportation energy demand by fuel type including, but not limited to, motor gasoline, distillate, jet fuel, and alternative fuels (such as CNG) not commonly associated with transportation. The current NEMS forecast horizon extends to the year 2010 and uses 1990 as the base year. Forecasts are generated through the separate consideration of energy consumption within the various modes of transport, including: private and fleet light-duty vehicles; aircraft; marine, rail, and truck freight; and various modes with minor overall impacts, such as mass transit and recreational boating. This approach is useful in assessing the impacts of policy initiatives, legislative mandates which affect individual modes of travel, and technological developments. The model also provides forecasts of selected intermediate values which are generated in order to determine energy consumption. These elements include estimates of passenger travel demand by automobile, air, or mass transit; estimates of the efficiency with which that demand is met; projections of vehicle stocks and the penetration of new technologies; and estimates of the demand for freight transport which are linked to forecasts of industrial output. Following the estimation of energy demand, TRAN produces forecasts of vehicular emissions of the following pollutants by source: oxides of sulfur, oxides of nitrogen, total carbon, carbon dioxide, carbon monoxide, and volatile organic compounds.

  14. Dominant delayed neutron precursors to model reactivity predictions for multiple fissioning nuclides

    SciTech Connect (OSTI)

    Loaiza, D.J.; Haskin, F.E.

    2000-01-01T23:59:59.000Z

    The product of cumulative yield and probability of neutron emission is used to assess the relative importance of known delayed neutron precursors. Thirteen precursors are consistently dominant. Nonlinear fits to experimental delayed neutron decay data distinguish the decay constants of the three longest-lived dominant precursors: {sup 87}Br, {sup 137}I, and {sup 88}Br. Sensitivity calculations based on a six-to seven-group transformation lead to a proposed seven-group formulation in which the group decay constants are those of dominant precursors: {sup 87}Br, {sup 137}I, {sup 88}Br, {sup 93}Rb, {sup 139}I, {sup 91}Br, and {sup 96}Rb. An alternative six-group formulation is obtained by using the mean of the {sup 137}I and {sup 88}Br decay constants for group 2. The use of the suggested dominant precursor decay constants improves the goodness of fit to experimental data compared to that obtained from nonlinear least squares in which both group yields and decay constants are determined empirically. Reactivity worth and transient analyses confirm that the positive reactivity scale is preserved in the transformation. A known bias in the negative reactivity scale is eliminated by forcing the half-life of the longest-lived group to be the 55.9-s half-life of {sup 87}Br. The proposed use of dominant precursor decay constants offers significant simplifications in data analysis and the analysis of fast, epithermal, and thermal reactors with multiple fissioning nuclides.

  15. Uranium Removal from Groundwater via In Situ Biostimulation: Field-Scale Modeling of Transport and Biological Processes

    SciTech Connect (OSTI)

    Yabusaki, Steven B.; Fang, Yilin; Long, Philip E.; Resch, Charles T.; Peacock, Aaron D.; Komlos, John; Jaffe, Peter R.; Morrison, Stan J.; Dayvault, Richard; White, David C.; Anderson, Robert T.

    2007-03-12T23:59:59.000Z

    During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community. In the present study, we use multicomponent reactive transport modeling to analyze data from the 2002 field experiment to 1) identify the dominant transport and biological processes controlling uranium mobility during biostimulation, 2) determine field-scale parameters for these modeled processes, and 3) apply the calibrated process models to history match observations during the 2003 field experiment. In spite of temporally and spatially variable observations during the field-scale biostimulation experiments, the coupled process simulation approach was able to establish a quantitative characterization of the principal flow, transport, and reaction processes that could be applied without modification to describe the 2003 field experiment. Insights gained from this analysis include field-scale estimates of bioavailable Fe(III) mineral, and the magnitude of uranium bioreduction during biostimulated growth of the iron-reducing and sulfate-reducing microorganisms.

  16. Vlasov modelling of parallel transport in a tokamak scrape-off layer

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Vlasov modelling of parallel transport in a tokamak scrape-off layer G. Manfredi Institut de.Devaux@ccfe.ac.uk Abstract. A one-dimensional Vlasov-Poisson model is used to describe the parallel transport in a tokamak transport in a tokamak scrape-off layer 2 1. Introduction One of the main challenges for future tokamak

  17. Modeling Studies on the Transport of Benzene and H2S in CO2-Water Systems

    SciTech Connect (OSTI)

    Zheng, L.; Spycher, N.; Xu, T.; Apps, J.; Kharaka, Y.; Birkholzer, J.T.

    2010-11-05T23:59:59.000Z

    In this study, reactive transport simulations were used to assess the mobilization and transport of organics with supercritical CO{sub 2} (SCC), and the co-injection and transport of H{sub 2}S with SCC. These processes were evaluated at conditions of typical storage reservoirs, and for cases of hypothetical leakage from a reservoir to an overlying shallower fresh water aquifer. Modeling capabilities were developed to allow the simulation of multiphase flow and transport of H{sub 2}O, CO{sub 2}, H{sub 2}S, as well as specific organic compounds (benzene), coupled with multicomponent geochemical reaction and transport. This included the development of a new simulator, TMVOC-REACT, starting from existing modules of the TOUGH2 family of codes. This work also included an extensive literature review, calculation, and testing of phase-partitioning properties for mixtures of the phases considered. The reactive transport simulations presented in this report are primarily intended to illustrate the capabilities of the new simulator. They are also intended to help evaluate and understand various processes at play, in a more qualitative than quantitative manner, and only for hypothetical scenarios. Therefore, model results are not intended as realistic assessments of groundwater quality changes for specific locations, and they certainly do not provide an exhaustive evaluation of all possible site conditions, especially given the large variability and uncertainty in hydrogeologic and geochemical parameter input into simulations. The first step in evaluating the potential mobilization and transport of organics was the identification of compounds likely to be present in deep storage formations, and likely to negatively impact freshwater aquifers if mobilized by SCC. On the basis of a literature review related to the occurrence of these organic compounds, their solubility in water and SCC, and their toxicity (as reflected by their maximum contaminant levels MCL), benzene was selected as a key compound for inclusion into numerical simulations. Note that considering additional organic compounds and/or mixtures of such compounds in the simulations was beyond the scope of this study, because of the effort required to research, calculate, and validate the phase-partitioning data necessary for simulations. The injection of CO{sub 2} into a deep saline aquifer was simulated, followed by modeling the leaching of benzene by SCC and transport of benzene to an overlying aquifer along a hypothetical leakage pathway. One- and two-dimensional models were set up for this purpose. The target storage formation was assumed to initially contain about 10{sup -4} ppm benzene. Model results indicate that: (1) SCC efficiently extracts benzene from the storage formation. (2) Assuming equilibrium, the content of benzene in SCC is roportional to the concentration of benzene in the aqueous and solid phases. (3) Benzene may co-migrate with CO{sub 2} into overlying aquifers if a leakage pathway is present. Because the aqueous solubility of benzene in contact with CO{sub 2} is lower than the aqueous solubility of CO{sub 2}, benzene is actually enriched in the CO{sub 2} phase as the plume advances. (4) For the case studied here, the resulting aqueous benzene concentration in the overlying aquifer is on the same order of magnitude as the initial concentration in the storage formation. This generic modeling study illustrates, in a semi-quantitative manner, the possible mobilization of benzene by SCC. The extent to which the mobilization of this organic compound evolves temporally and spatially depends on a large number of controlling parameters and is largely site specific. Therefore, for more 'truly' predictive work, further sensitivity studies should be conducted, and further modeling should be integrated with site-specific laboratory and/or field experimental data. The co-injection of H{sub 2}S with CO{sub 2} into a deep saline aquifer was also simulated. In addition, the model considered leakage of the supercritical CO{sub 2}+H{sub 2}S mixture along a preferential p

  18. Transport Corrections in Nodal Diffusion Codes for HTR Modeling

    SciTech Connect (OSTI)

    Abderrafi M. Ougouag; Frederick N. Gleicher

    2010-08-01T23:59:59.000Z

    The cores and reflectors of High Temperature Reactors (HTRs) of the Next Generation Nuclear Plant (NGNP) type are dominantly diffusive media from the point of view of behavior of the neutrons and their migration between the various structures of the reactor. This means that neutron diffusion theory is sufficient for modeling most features of such reactors and transport theory may not be needed for most applications. Of course, the above statement assumes the availability of homogenized diffusion theory data. The statement is true for most situations but not all. Two features of NGNP-type HTRs require that the diffusion theory-based solution be corrected for local transport effects. These two cases are the treatment of burnable poisons (BP) in the case of the prismatic block reactors and, for both pebble bed reactor (PBR) and prismatic block reactor (PMR) designs, that of control rods (CR) embedded in non-multiplying regions near the interface between fueled zones and said non-multiplying zones. The need for transport correction arises because diffusion theory-based solutions appear not to provide sufficient fidelity in these situations.

  19. Modeling preferential water flow and solute transport in unsaturated soil using the active region model

    SciTech Connect (OSTI)

    Sheng, F.; Wang, K.; Zhang, R.; Liu, H.H.

    2009-03-15T23:59:59.000Z

    Preferential flow and solute transport are common processes in the unsaturated soil, in which distributions of soil water content and solute concentrations are often characterized as fractal patterns. An active region model (ARM) was recently proposed to describe the preferential flow and transport patterns. In this study, ARM governing equations were derived to model the preferential soil water flow and solute transport processes. To evaluate the ARM equations, dye infiltration experiments were conducted, in which distributions of soil water content and Cl{sup -} concentration were measured. Predicted results using the ARM and the mobile-immobile region model (MIM) were compared with the measured distributions of soil water content and Cl{sup -} concentration. Although both the ARM and the MIM are two-region models, they are fundamental different in terms of treatments of the flow region. The models were evaluated based on the modeling efficiency (ME). The MIM provided relatively poor prediction results of the preferential flow and transport with negative ME values or positive ME values less than 0.4. On the contrary, predicted distributions of soil water content and Cl- concentration using the ARM agreed reasonably well with the experimental data with ME values higher than 0.8. The results indicated that the ARM successfully captured the macroscopic behavior of preferential flow and solute transport in the unsaturated soil.

  20. Preliminary Environmental Flow and Transport Modeling at the INEEL

    SciTech Connect (OSTI)

    J. D. Navratil; J. M. McCarthy; S. O. Magnuson

    1999-09-26T23:59:59.000Z

    The Idaho National Engineering and Environmental Laboratory (INEEL) is located in southeastern Idaho in the USA. The primary mission since the laboratory was founded in 1949 has been nuclear reactor research. Fifty-two reactors have been built and operated on the INEEL. Other principal activities at the laboratory have been reprocessing of spent nuclear fuel. Low-level radioactive waste generated on site and mixed and transuranic waste from the Rocky Flats plutonium processing facility in Colorado has been disposed on the INEEL at the Radioactive Waste Management Complex (RWMC). Waste disposal at the RWMC began in 1952 with shallow land burial in pits and trenches. The INEEL was placed on the National Priorities List (NPL) in 1989. The resulting environmental assessments of the potential negative health impacts of disposed waste at the RWMC have required the use of predictive numerical simulations. A petroleum reservoir simulator called TETRAD was modified for use in simulating environmental flow and transport. Use of this code has allowed the complex subsurface stratigraphy to be simulated, including an extensive region of unsaturated fractured basalt. Dual continual simulation approaches have been used to assess combined aqueous- and gaseous-phase transport of volatile organic compounds as well as dissolved-phase transport of radionuclides. Calibration of the simulator to available monitoring data has increased the confidence in the simulator results to the point where the model sensitivities are being used to direct additional characterization efforts. Eventually, as the model calibration improves and confidence in the model predictions increases, the simulator will be used as a decision tool for selecting remedial alternatives for the wastes buried at the RWMC. An overview of the overall program including a summary of laboratory actinide migration studies will be presented.

  1. Preliminary Environmental Flow and Transport Modeling at the INEEL

    SciTech Connect (OSTI)

    Magnuson, Swen O; Mccarthy, James Michael; Navratil, James Dale

    1999-09-01T23:59:59.000Z

    The Idaho National Engineering and Environmental Laboratory (INEEL) is located in southeastern Idaho in the USA. The primary mission since the laboratory was founded in 1949 has been nuclear reactor research. Fifty-two reactors have been built and operated on the INEEL. Other principal activities at the laboratory have been reprocessing of spent nuclear fuel. Low-level radioactive waste generated on site and mixed and transuranic waste from the Rocky Flats plutonium processing facility in Colorado has been disposed on the INEEL at the Radioactive Waste Management Complex (RWMC). Waste disposal at the RWMC began in 1952 with shallow land burial in pits and trenches. The INEEL was placed on the National Priorities List (NPL) in 1989. The resulting environmental assessments of the potential negative health impacts of disposed waste at the RWMC have required the use of predictive numerical simulations. A petroleum reservoir simulator called TETRAD was modified for use in simulating environmental flow and transport. Use of this code has allowed the complex subsurface stratigraphy to be simulated, including an extensive region of unsaturated fractured basalt. Dual continual simulation approaches have been used to assess combined aqueous- and gaseous-phase transport of volatile organic compounds as well as dissolved-phase transport of radionuclides. Calibration of the simulator to available monitoring data has increased the confidence in the simulator results to the point where the model sensitivities are being used to direct additional characterization efforts. Eventually, as the model calibration improves and confidence in the model predictions increases, the simulator will be used as a decision tool for selecting remedial alternatives for the wastes buried at the RWMC. An overview of the overall program including a summary of laboratory actinide migration studies will be presented.

  2. Thermoelectric transport in the coupled valence-band model

    E-Print Network [OSTI]

    Ramu, Ashok; Cassels, Laura; Hackman, Nathan; Lu, Hong; Zide, Joshua; Bowers, John E.

    2011-01-01T23:59:59.000Z

    109, 033704 ?2011? Thermoelectric transport in the coupledapplied to the problem of thermoelectric transport in p-typeef?ciency p-type thermoelectric material, are calculated and

  3. Environmental Transport Input Parameters for the Biosphere Model

    SciTech Connect (OSTI)

    M. Wasiolek

    2004-09-10T23:59:59.000Z

    This analysis report is one of the technical reports documenting the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), a biosphere model supporting the total system performance assessment for the license application (TSPA-LA) for the geologic repository at Yucca Mountain. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows relationships among the reports developed for biosphere modeling and biosphere abstraction products for the TSPA-LA, as identified in the ''Technical Work Plan for Biosphere Modeling and Expert Support'' (BSC 2004 [DIRS 169573]) (TWP). This figure provides an understanding of how this report contributes to biosphere modeling in support of the license application (LA). This report is one of the five reports that develop input parameter values for the biosphere model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes the conceptual model and the mathematical model. The input parameter reports, shown to the right of the Biosphere Model Report in Figure 1-1, contain detailed description of the model input parameters. The output of this report is used as direct input in the ''Nominal Performance Biosphere Dose Conversion Factor Analysis'' and in the ''Disruptive Event Biosphere Dose Conversion Factor Analysis'' that calculate the values of biosphere dose conversion factors (BDCFs) for the groundwater and volcanic ash exposure scenarios, respectively. The purpose of this analysis was to develop biosphere model parameter values related to radionuclide transport and accumulation in the environment. These parameters support calculations of radionuclide concentrations in the environmental media (e.g., soil, crops, animal products, and air) resulting from a given radionuclide concentration at the source of contamination (i.e., either in groundwater or in volcanic ash). The analysis was performed in accordance with the TWP (BSC 2004 [DIRS 169573]).

  4. To appear in IET Generation, Transmission and Distribution, special issue on "Markets and Economics in Power Systems" 1 Abstract: This paper proposes a novel reactive power dispatch model that takes into account both the technical and

    E-Print Network [OSTI]

    Cañizares, Claudio A.

    -Defining the Reactive Power Dispatch Problem in the Context of Competitive Electricity Markets C. A. Cañizares K in Power Systems" 1 Abstract: This paper proposes a novel reactive power dispatch model that takes into account both the technical and economical aspects associated with reactive power dispatch in the context

  5. Environmental Transport Input Parameters for the Biosphere Model

    SciTech Connect (OSTI)

    M. A. Wasiolek

    2003-06-27T23:59:59.000Z

    This analysis report is one of the technical reports documenting the Environmental Radiation Model for Yucca Mountain Nevada (ERMYN), a biosphere model supporting the total system performance assessment (TSPA) for the geologic repository at Yucca Mountain. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows relationships among the reports developed for biosphere modeling and biosphere abstraction products for the TSPA, as identified in the ''Technical Work Plan: for Biosphere Modeling and Expert Support'' (TWP) (BSC 2003 [163602]). Some documents in Figure 1-1 may be under development and not available when this report is issued. This figure provides an understanding of how this report contributes to biosphere modeling in support of the license application (LA), but access to the listed documents is not required to understand the contents of this report. This report is one of the reports that develops input parameter values for the biosphere model. The ''Biosphere Model Report'' (BSC 2003 [160699]) describes the conceptual model, the mathematical model, and the input parameters. The purpose of this analysis is to develop biosphere model parameter values related to radionuclide transport and accumulation in the environment. These parameters support calculations of radionuclide concentrations in the environmental media (e.g., soil, crops, animal products, and air) resulting from a given radionuclide concentration at the source of contamination (i.e., either in groundwater or volcanic ash). The analysis was performed in accordance with the TWP (BSC 2003 [163602]). This analysis develops values of parameters associated with many features, events, and processes (FEPs) applicable to the reference biosphere (DTN: M00303SEPFEPS2.000 [162452]), which are addressed in the biosphere model (BSC 2003 [160699]). The treatment of these FEPs is described in BSC (2003 [160699], Section 6.2). Parameter values developed in this report, and the related FEPs, are listed in Table 1-1. The relationship between the parameters and FEPs was based on a comparison of the parameter definition and the FEP descriptions as presented in BSC (2003 [160699], Section 6.2). The parameter values developed in this report support the biosphere model and are reflected in the TSPA through the biosphere dose conversion factors (BDCFs). Biosphere modeling focuses on radionuclides screened for the TSPA-LA (BSC 2002 [160059]). The same list of radionuclides is used in this analysis (Section 6.1.4). The analysis considers two human exposure scenarios (groundwater and volcanic ash) and climate change (Section 6.1.5). This analysis combines and revises two previous reports, ''Transfer Coefficient Analysis'' (CRWMS M&O 2000 [152435]) and ''Environmental Transport Parameter Analysis'' (CRWMS M&O 2001 [152434]), because the new ERMYN biosphere model requires a redefined set of input parameters. The scope of this analysis includes providing a technical basis for the selection of radionuclide- and element-specific biosphere parameters (except for Kd) that are important for calculating BDCFs based on the available radionuclide inventory abstraction data. The environmental transport parameter values were developed specifically for use in the biosphere model and may not be appropriate for other applications.

  6. Reactive Maintenance

    Broader source: Energy.gov [DOE]

    Reactive maintenance follows a run-it-until-it-breaks strategy where no actions or efforts are taken to maintain equipment as intended by the manufacturer. Studies indicate this is still the predominant mode of maintenance for Federal facilities.

  7. Aerosols and clouds in chemical transport models and climate models.

    SciTech Connect (OSTI)

    Lohmann,U.; Schwartz, S. E.

    2008-03-02T23:59:59.000Z

    Clouds exert major influences on both shortwave and longwave radiation as well as on the hydrological cycle. Accurate representation of clouds in climate models is a major unsolved problem because of high sensitivity of radiation and hydrology to cloud properties and processes, incomplete understanding of these processes, and the wide range of length scales over which these processes occur. Small changes in the amount, altitude, physical thickness, and/or microphysical properties of clouds due to human influences can exert changes in Earth's radiation budget that are comparable to the radiative forcing by anthropogenic greenhouse gases, thus either partly offsetting or enhancing the warming due to these gases. Because clouds form on aerosol particles, changes in the amount and/or composition of aerosols affect clouds in a variety of ways. The forcing of the radiation balance due to aerosol-cloud interactions (indirect aerosol effect) has large uncertainties because a variety of important processes are not well understood precluding their accurate representation in models.

  8. Pion-nucleus reactions in a microscopic transport model

    E-Print Network [OSTI]

    A. Engel; W. Cassing; U. Mosel; M. Schäfer; Gy. Wolf

    1993-07-07T23:59:59.000Z

    We analyse pion-nucleus reactions in a microscopic transport model of the BUU type, which propagates nucleons, pions, deltas and N(1440)-resonances explicitly in space and time. In particular we examine pion absorption and inelastic scattering cross sections for pion kinetic energies T(pi) =85-315MeV and various target masses. In general, the mass-dependence of the experimental data is well described for energies up to the delta-resonance (\\approx 160 MeV) while the absorption cross sections are somewhat overestimated for the higher energies. In addition we study the possible dynamical effects of delta- and pion-potentials in the medium on various observables as well as alternative models for the in-medium delta-width.

  9. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    SciTech Connect (OSTI)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01T23:59:59.000Z

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle model simulates more accurately than the ADRE.

  10. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    SciTech Connect (OSTI)

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L. [Pacific Northwest Lab., Richland, WA (United States)

    1981-01-01T23:59:59.000Z

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

  11. A hybrid model for particle transport and electron energy distributions in positive column electrical discharges using equivalent species transport

    E-Print Network [OSTI]

    Kushner, Mark

    A hybrid model for particle transport and electron energy distributions in positive column species are generated in the kinetic module. The hybrid model has been used to examine electron energy which has discrete negative energies representing bound states, and a positive continuum representing

  12. Compendium of Material Composition Data for Radiation Transport Modeling

    SciTech Connect (OSTI)

    McConn, Ronald J.; Gesh, Christopher J.; Pagh, Richard T.; Rucker, Robert A.; Williams III, Robert

    2011-03-04T23:59:59.000Z

    Introduction Meaningful simulations of radiation transport applications require realistic definitions of material composition and densities. When seeking that information for applications in fields such as homeland security, radiation shielding and protection, and criticality safety, researchers usually encounter a variety of materials for which elemental compositions are not readily available or densities are not defined. Publication of the Compendium of Material Composition Data for Radiation Transport Modeling, Revision 0, in 2006 was the first step toward mitigating this problem. Revision 0 of this document listed 121 materials, selected mostly from the combined personal libraries of staff at the Pacific Northwest National Laboratory (PNNL), and thus had a scope that was recognized at the time to be limited. Nevertheless, its creation did provide a well-referenced source of some unique or hard-to-define material data in a format that could be used directly in radiation transport calculations being performed at PNNL. Moreover, having a single common set of material definitions also helped to standardize at least one aspect of the various modeling efforts across the laboratory by providing separate researchers the ability to compare different model results using a common basis of materials. The authors of the 2006 compendium understood that, depending on its use and feedback, the compendium would need to be revised to correct errors or inconsistencies in the data for the original 121 materials, as well as to increase (per users suggestions) the number of materials listed. This 2010 revision of the compendium has accomplished both of those objectives. The most obvious change is the increased number of materials from 121 to 372. The not-so-obvious change is the mechanism used to produce the data listed here. The data listed in the 2006 document were compiled, evaluated, entered, and error-checked by a group of individuals essentially by hand, providing no library file or mechanism for revising the data in a consistent and traceable manner. The authors of this revision have addressed that problem by first compiling all of the information (i.e., numbers and references) for all the materials into a single database, maintained at PNNL, that was then used as the basis for this document.

  13. Active patterning and asymmetric transport in a model actomyosin network

    E-Print Network [OSTI]

    Shenshen Wang; Peter G. Wolynes

    2014-12-19T23:59:59.000Z

    Cytoskeletal networks, which are essentially motor-filament assemblies, play a major role in many developmental processes involving structural remodeling and shape changes. These are achieved by nonequilibrium self-organization processes that generate functional patterns and drive intracellular transport. We construct a minimal physical model that incorporates the coupling between nonlinear elastic responses of individual filaments and force-dependent motor action. By performing stochastic simulations we show that the interplay of motor processes, described as driving anti-correlated motion of the network vertices, and the network connectivity, which determines the percolation character of the structure, can indeed capture the dynamical and structural cooperativity which gives rise to diverse patterns observed experimentally. The buckling instability of individual filaments is found to play a key role in localizing collapse events due to local force imbalance. Motor-driven buckling-induced node aggregation provides a dynamic mechanism that stabilizes the two dimensional patterns below the apparent static percolation limit. Coordinated motor action is also shown to suppress random thermal noise on large time scales, the two dimensional configuration that the system starts with thus remaining planar during the structural development. By carrying out similar simulations on a three dimensional anchored network, we find that the myosin-driven isotropic contraction of a well-connected actin network, when combined with mechanical anchoring that confers directionality to the collective motion, may represent a novel mechanism of intracellular transport, as revealed by chromosome translocation in the starfish oocyte.

  14. header for SPIE use Laboratory Data and Model Comparisons of the Transport of Chemical

    E-Print Network [OSTI]

    Cal, Mark P.

    header for SPIE use Laboratory Data and Model Comparisons of the Transport of Chemical Signatures to examine the breadth of conditions that impact chemical signature transport, from the buried location results from the T2TNT code, specifically developed to evaluate the buried landmine chemical transport

  15. Fractional advection-dispersion equations for1 modeling transport at the Earth surface2

    E-Print Network [OSTI]

    Bäumer, Boris

    Fractional advection-dispersion equations for1 modeling transport at the Earth surface2 Rina partial differential equations such as the advection-dispersion equation12 (ADE) begin with assumptions biomechanical transport and mixing29 by bioturbation, and the transport of sediment particles and sediment

  16. Modeling of coulpled deformation and permeability evolution during fault reactivation induced by deep underground injection of CO2

    SciTech Connect (OSTI)

    Cappa, F.; Rutqvist, J.

    2010-06-01T23:59:59.000Z

    The interaction between mechanical deformation and fluid flow in fault zones gives rise to a host of coupled hydromechanical processes fundamental to fault instability, induced seismicity, and associated fluid migration. In this paper, we discuss these coupled processes in general and describe three modeling approaches that have been considered to analyze fluid flow and stress coupling in fault-instability processes. First, fault hydromechanical models were tested to investigate fault behavior using different mechanical modeling approaches, including slip interface and finite-thickness elements with isotropic or anisotropic elasto-plastic constitutive models. The results of this investigation showed that fault hydromechanical behavior can be appropriately represented with the least complex alternative, using a finite-thickness element and isotropic plasticity. We utilized this pragmatic approach coupled with a strain-permeability model to study hydromechanical effects on fault instability during deep underground injection of CO{sub 2}. We demonstrated how such a modeling approach can be applied to determine the likelihood of fault reactivation and to estimate the associated loss of CO{sub 2} from the injection zone. It is shown that shear-enhanced permeability initiated where the fault intersects the injection zone plays an important role in propagating fault instability and permeability enhancement through the overlying caprock.

  17. Simulating aerosols using a chemical transport model with assimilation of satellite aerosol retrievals

    E-Print Network [OSTI]

    Zender, Charles

    Simulating aerosols using a chemical transport model with assimilation of satellite aerosol for simulating aerosols has been developed using a chemical transport model together with an assimilation of satellite aerosol retrievals. The methodology and model components are described in this paper

  18. d+Au Collisions from A MultiPhase Transport Model

    E-Print Network [OSTI]

    Lin, Zi-wei

    d+Au Collisions from A MultiPhase Transport Model Structure of AMPT Model Results for d's Parton Cascade) Partons freeze out Lund fragmentation to hadrons using HIJING ART (A Relativistic Transport model for hadrons) A+B Final output Zhang et al, PRC61; ZWL et al, PRC64, NPA698 Wang

  19. Plutonium-238 observations as a test of modeled transport and surface deposition of meteoric smoke particles

    E-Print Network [OSTI]

    Chipperfield, Martyn

    Plutonium-238 observations as a test of modeled transport and surface deposition of meteoric smoke chemistry-climate model (CCM) to simulate the transport and deposition of plutonium- 238 oxide nanoparticles. P. Chipperfield, and J. M. C. Plane (2013), Plutonium-238 observations as a test of modeled

  20. Computers & Geosciences 29 (2003) 351359 A case against Kd-based transport models: natural attenuation

    E-Print Network [OSTI]

    Polly, David

    )-based transport model. The study site is a contaminated groundwater aquifer underneath a uranium mill tailings groundwater for 1600 years. The coupled model shows that groundwater­sediment interactions result in multiple. Keywords: Geochemical modeling; Contaminant; Transport; Coupled processes 1. Introduction Accurate

  1. Predicting tropospheric ozone and hydroxyl radical in a global, three-dimensional, chemistry, transport, and deposition model

    SciTech Connect (OSTI)

    Atherton, C.S.

    1995-01-05T23:59:59.000Z

    Two of the most important chemically reactive tropospheric gases are ozone (O{sub 3}) and the hydroxyl radical (OH). Although ozone in the stratosphere is a necessary protector against the sun`s radiation, tropospheric ozone is actually a pollutant which damages materials and vegetation, acts as a respiratory irritant, and is a greenhouse gas. One of the two main sources of ozone in the troposphere is photochemical production. The photochemistry is initiated when hydrocarbons and carbon monoxide (CO) react with nitrogen oxides (NO{sub x} = NO + NO{sub 2}) in the presence of sunlight. Reaction with the hydroxyl radical, OH, is the main sink for many tropospheric gases. The hydroxyl radical is highly reactive and has a lifetime on the order of seconds. Its formation is initiated by the photolysis of tropospheric ozone. Tropospheric chemistry involves a complex, non-linear set of chemical reactions between atmospheric species that vary substantially in time and space. To model these and other species on a global scale requires the use of a global, three-dimensional chemistry, transport, and deposition (CTD) model. In this work, I developed two such three dimensional CTD models. The first model incorporated the chemistry necessary to model tropospheric ozone production from the reactions of nitrogen oxides with carbon monoxide (CO) and methane (CH{sub 4}). The second also included longer-lived alkane species and the biogenic hydrocarbon isoprene, which is emitted by growing plants and trees. The models` ability to predict a number of key variables (including the concentration of O{sub 3}, OH, and other species) were evaluated. Then, several scenarios were simulated to understand the change in the chemistry of the troposphere since preindustrial times and the role of anthropogenic NO{sub x} on present day conditions.

  2. Transportation planning for mega events : a model of urban change

    E-Print Network [OSTI]

    Kassens, Eva

    2009-01-01T23:59:59.000Z

    My study is about opportunities for revolutionary developments in urban transport. Often, we think of transport and urban development as an evolutionary process, yet there exist a few opportunities for cities to revolutionize ...

  3. Heavy Duty Diesel Particulate Matter and Fuel Consumption Modeling for Transportation Analysis

    E-Print Network [OSTI]

    Scora, George Alexander

    2011-01-01T23:59:59.000Z

    Model for Heavy Duty Diesel Vehicles. TransportationAir Contaminant Emissions from Diesel- fueled Engines. Factfor Measuring Emissions from Diesel Engines. 1. Regulated

  4. The cationic amino acid transporter 2 is induced in inflammatory lung models and regulates lung fibrosis

    E-Print Network [OSTI]

    Niese, Kathryn A; Chiaramonte, Monica G; Ellies, Lesley G; Rothenberg, Marc E; Zimmermann, Nives

    2010-01-01T23:59:59.000Z

    acid transporter 2 is induced in inflammatory lung modelsand regulates lung fibrosis Respiratory Research 2010, 11:872 is induced in inflammatory lung models and regulates lung

  5. Full-fuel-cycle modeling for alternative transportation fuels

    SciTech Connect (OSTI)

    Bell, S.R.; Gupta, M. [Univ. of Alabama, Tuscaloosa, AL (United States); Greening, L.A. [Lawrence Berkeley National Lab., CA (United States). Energy and Environment Div.

    1995-12-01T23:59:59.000Z

    Utilization of alternative fuels in the transportation sector has been identified as a potential method for mitigation of petroleum-based energy dependence and pollutant emissions from mobile sources. Traditionally, vehicle tailpipe emissions have served as sole data when evaluating environmental impact. However, considerable differences in extraction and processing requirements for alternative fuels makes evident the need to consider the complete fuel production and use cycle for each fuel scenario. The work presented here provides a case study applied to the southeastern region of the US for conventional gasoline, reformulated gasoline, natural gas, and methanol vehicle fueling. Results of the study demonstrate the significance of the nonvehicle processes, such as fuel refining, in terms of energy expenditure and emissions production. Unique to this work is the application of the MOBILE5 mobile emissions model in the full-fuel-cycle analysis. Estimates of direct and indirect greenhouse gas production are also presented and discussed using the full-cycle-analysis method.

  6. Stochastic modeling of cargo transport by teams of molecular motors

    E-Print Network [OSTI]

    Sarah Klein; Cécile Appert-Rolland; Ludger Santen

    2014-07-16T23:59:59.000Z

    Many different types of cellular cargos are transported bidirectionally along microtubules by teams of molecular motors. The motion of this cargo-motors system has been experimentally characterized in vivo as processive with rather persistent directionality. Different theoretical approaches have been suggested in order to explore the origin of this kind of motion. An effective theoretical approach, introduced by M\\"uller et al., describes the cargo dynamics as a tug-of-war between different kinds of motors. An alternative approach has been suggested recently by Kunwar et al., who considered the coupling between motor and cargo in more detail. Based on this framework we introduce a model considering single motor positions which we propagate in continuous time. Furthermore, we analyze the possible influence of the discrete time update schemes used in previous publications on the system's dynamic.

  7. Automated Modelling of Reactive Discrete Event Systems from External Behavioural Data

    E-Print Network [OSTI]

    Boyer, Edmond

    Petri nets. I. INTRODUCTION Modelling is an important stage during the systems' developing life-cycle

  8. Modeling the Prospects for Hydrogen Powered Transportation Through 2100

    E-Print Network [OSTI]

    Sandoval, Reynaldo.

    Hydrogen fueled transportation has been proposed as a low carbon alternative to the current gasoline-powered

  9. Validation Analysis of the Shoal Groundwater Flow and Transport Model

    SciTech Connect (OSTI)

    A. Hassan; J. Chapman

    2008-11-01T23:59:59.000Z

    Environmental restoration at the Shoal underground nuclear test is following a process prescribed by a Federal Facility Agreement and Consent Order (FFACO) between the U.S. Department of Energy, the U.S. Department of Defense, and the State of Nevada. Characterization of the site included two stages of well drilling and testing in 1996 and 1999, and development and revision of numerical models of groundwater flow and radionuclide transport. Agreement on a contaminant boundary for the site and a corrective action plan was reached in 2006. Later that same year, three wells were installed for the purposes of model validation and site monitoring. The FFACO prescribes a five-year proof-of-concept period for demonstrating that the site groundwater model is capable of producing meaningful results with an acceptable level of uncertainty. The corrective action plan specifies a rigorous seven step validation process. The accepted groundwater model is evaluated using that process in light of the newly acquired data. The conceptual model of ground water flow for the Project Shoal Area considers groundwater flow through the fractured granite aquifer comprising the Sand Springs Range. Water enters the system by the infiltration of precipitation directly on the surface of the mountain range. Groundwater leaves the granite aquifer by flowing into alluvial deposits in the adjacent basins of Fourmile Flat and Fairview Valley. A groundwater divide is interpreted as coinciding with the western portion of the Sand Springs Range, west of the underground nuclear test, preventing flow from the test into Fourmile Flat. A very low conductivity shear zone east of the nuclear test roughly parallels the divide. The presence of these lateral boundaries, coupled with a regional discharge area to the northeast, is interpreted in the model as causing groundwater from the site to flow in a northeastward direction into Fairview Valley. Steady-state flow conditions are assumed given the absence of groundwater withdrawal activities in the area. The conceptual and numerical models were developed based upon regional hydrogeologic investigations conducted in the 1960s, site characterization investigations (including ten wells and various geophysical and geologic studies) at Shoal itself prior to and immediately after the test, and two site characterization campaigns in the 1990s for environmental restoration purposes (including eight wells and a year-long tracer test). The new wells are denoted MV-1, MV-2, and MV-3, and are located to the northnortheast of the nuclear test. The groundwater model was generally lacking data in the north-northeastern area; only HC-1 and the abandoned PM-2 wells existed in this area. The wells provide data on fracture orientation and frequency, water levels, hydraulic conductivity, and water chemistry for comparison with the groundwater model. A total of 12 real-number validation targets were available for the validation analysis, including five values of hydraulic head, three hydraulic conductivity measurements, three hydraulic gradient values, and one angle value for the lateral gradient in radians. In addition, the fracture dip and orientation data provide comparisons to the distributions used in the model and radiochemistry is available for comparison to model output. Goodness-of-fit analysis indicates that some of the model realizations correspond well with the newly acquired conductivity, head, and gradient data, while others do not. Other tests indicated that additional model realizations may be needed to test if the model input distributions need refinement to improve model performance. This approach (generating additional realizations) was not followed because it was realized that there was a temporal component to the data disconnect: the new head measurements are on the high side of the model distributions, but the heads at the original calibration locations themselves have also increased over time. This indicates that the steady-state assumption of the groundwater model is in error. To test the robustness of the model d

  10. Seven surrogate precursors for modeling delayed neutron decay and predicting reactivity

    SciTech Connect (OSTI)

    Loaiza, D.J.; Haskin, F.E.

    1997-12-31T23:59:59.000Z

    The use of a different set of group decay constants for each fissionable nuclide complicates analysis of the dynamic behavior of fast reactors. A fast reactor containing six principal fissioning nuclides of uranium and plutonium must, in effect, be described by 36 delayed neutron groups. Additionally, the use of group decay constants that depend on the neutron energy spectrum makes it difficult to select values that describe the dynamic response of epithermal systems because virtually all delayed neutron activity measurements have been performed for fast or thermal-neutron-induced fission. Clearly, it would be desirable to have a single set of group decay constants that could be applied to all fissionable nuclides. A set of seven fixed decay constants is proposed herein. Each of the proposed decay constants is associated with a specific, dominant delayed neutron precursor. In effect, each group is represented by a single surrogate precursor. Using recently measured delayed neutron activities for U-235 and Np-237, the proposed set of decay constants actually improved the goodness of fit to the data. For other fissionable nuclides lacking experimental data, a method has been devised to obtain yields consistent with the proposed set of decay constants from the traditional six-group parameters. This transformation is accomplished without altering the traditional inferred reactivity scale.

  11. Real-time capable first principle based modelling of tokamak turbulent transport

    E-Print Network [OSTI]

    Breton, S; Felici, F; Imbeaux, F; Aniel, T; Artaud, J F; Baiocchi, B; Bourdelle, C; Camenen, Y; Garcia, J

    2015-01-01T23:59:59.000Z

    A real-time capable core turbulence tokamak transport model is developed. This model is constructed from the regularized nonlinear regression of quasilinear gyrokinetic transport code output. The regression is performed with a multilayer perceptron neural network. The transport code input for the neural network training set consists of five dimensions, and is limited to adiabatic electrons. The neural network model successfully reproduces transport fluxes predicted by the original quasilinear model, while gaining five orders of magnitude in computation time. The model is implemented in a real-time capable tokamak simulator, and simulates a 300s ITER discharge in 10s. This proof-of-principle for regression based transport models anticipates a significant widening of input space dimensionality and physics realism for future training sets. This aims to provide unprecedented computational speed coupled with first-principle based physics for real-time control and integrated modelling applications.

  12. Performance Assessment of Different Control Structures for Generic Reactive Distillation Using Linear and Nonlinear Process Models

    E-Print Network [OSTI]

    Al-Arfaj, Muhammad A.

    compares the closed-loop performance of three control structures using an approximate linear model. Responses based on the linear model for various control structures show a good agreement when compared of the linear model is shown to be better in a single-end control system than in a dual-end control system

  13. Long-Range Atmospheric Transport of Polycyclic Aromatic Hydrocarbons: A Global 3-D Model Analysis Including Evaluation of Arctic Sources

    E-Print Network [OSTI]

    Friedman, Carey

    We use the global 3-D chemical transport model GEOS-Chem to simulate long-range atmospheric transport of polycyclic aromatic hydrocarbons (PAHs). To evaluate the model’s ability to simulate PAHs with different volatilities, ...

  14. ReaxFF Reactive Force Field for Solid Oxide Fuel Cell Systems with Application to Oxygen Ion Transport in Yttria-Stabilized Zirconia

    E-Print Network [OSTI]

    Goddard III, William A.

    through yttria-stabilized zirconia (YSZ) solid oxide fuel cell (SOFC) membranes. All parameters for ReaxReaxFF Reactive Force Field for Solid Oxide Fuel Cell Systems with Application to Oxygen Ion temperature, leading to applications as oxygen sensors and as membranes for high temperature solid oxide fuel

  15. Modeling of diffusive mass transport in micropores in cement based materials

    SciTech Connect (OSTI)

    Yamaguchi, Tetsuji, E-mail: yamaguchi.tetsuji@jaea.go.j [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan); Negishi, Kumi [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan); Taiheiyo Consultant Company Limited, 2-4-2, Osaku, Sakura, Chiba 285-8655 (Japan); Hoshino, Seiichi; Tanaka, Tadao [Japan Atomic Energy Agency, Shirakata, Tokai, Ibaraki 319-1195 (Japan)

    2009-12-15T23:59:59.000Z

    In order to predict long-term leaching behavior of cement constituents for safety assessments of radioactive waste disposal, we modeled diffusive mass transport in micropores in cement based materials. Based on available knowledge on the pore structure, we developed a transport porosity model that enables us to estimate effective porosity available for diffusion (transport porosity) in cement based materials. We microscopically examined the pore structure of hardened cement pastes to partially verify the model. Effective diffusivities of tritiated water in hardened cement pastes were also obtained experimentally, and were shown to be proportional to the estimated transport porosity.

  16. TRANSVIP: a solute transport model based on the spatial variability of intrinsic permeability

    E-Print Network [OSTI]

    Freeze, Geoffrey Allan

    1989-01-01T23:59:59.000Z

    groundwater flow and solute transport in three dimensions in both saturated and unsaturated porous media. The model simulates mechanical dispersion using a spatially vari- able intrinsic permeability field. This approach provides a, more realistic physical.... TRANSVIP is a three-dimensional flow and transport model capable of simulating contaminant transport in both saturated and unsaturated porous me- dia and does not assume Fickian dispersion. In TRANSVIP, the flow deviations that cause mechanical...

  17. FEMA: a Finite Element Model of Material Transport through Aquifers

    SciTech Connect (OSTI)

    Yeh, G.T.; Huff, D.D.

    1985-01-01T23:59:59.000Z

    This report documents the construction, verification, and demonstration of a Finite Element Model of Material Transport through Aquifers (FEMA). The particular features of FEMA are its versatility and flexibility to deal with as many real-world problems as possible. Mechanisms included in FEMA are: carrier fluid advection, hydrodynamic dispersion and molecular diffusion, radioactive decay, sorption, source/sinks, and degradation due to biological, chemical as well as physical processes. Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Prescribed concentration on the Dirichlet boundary, given gradient on the Neumann boundary segment, and flux at each Cauchy boundary segment can vary independently of each other. The aquifer may consist of as many formations as desired. Either completely confined or completely unconfined or partially confined and partially unconfined aquifers can be dealt with effectively. FEMA also includes transient leakage to or from the aquifer of interest through confining beds from or to aquifers lying below and/or above.

  18. Reactive Gliosis Reactive Oxygen Species: Superoxide

    E-Print Network [OSTI]

    . By sensing the electric signals generated by other 3368 Reactive Gliosis #12;individuals, mormyrids are alsoReactive Gliosis Glial Scar Reactive Oxygen Species: Superoxide Anions Neuroinflammation motor output. Reafferent Control in Electric Communication Reafferent Control in Electric Communication

  19. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 2

    SciTech Connect (OSTI)

    NONE

    1998-01-01T23:59:59.000Z

    The attachments contained within this appendix provide additional details about the model development and estimation process which do not easily lend themselves to incorporation in the main body of the model documentation report. The information provided in these attachments is not integral to the understanding of the model`s operation, but provides the reader with opportunity to gain a deeper understanding of some of the model`s underlying assumptions. There will be a slight degree of replication of materials found elsewhere in the documentation, made unavoidable by the dictates of internal consistency. Each attachment is associated with a specific component of the transportation model; the presentation follows the same sequence of modules employed in Volume 1. The following attachments are contained in Appendix F: Fuel Economy Model (FEM)--provides a discussion of the FEM vehicle demand and performance by size class models; Alternative Fuel Vehicle (AFV) Model--describes data input sources and extrapolation methodologies; Light-Duty Vehicle (LDV) Stock Model--discusses the fuel economy gap estimation methodology; Light Duty Vehicle Fleet Model--presents the data development for business, utility, and government fleet vehicles; Light Commercial Truck Model--describes the stratification methodology and data sources employed in estimating the stock and performance of LCT`s; Air Travel Demand Model--presents the derivation of the demographic index, used to modify estimates of personal travel demand; and Airborne Emissions Model--describes the derivation of emissions factors used to associate transportation measures to levels of airborne emissions of several pollutants.

  20. A non-isothermal PEM fuel cell model including two water transport mechanisms in the

    E-Print Network [OSTI]

    Münster, Westfälische Wilhelms-Universität

    A non-isothermal PEM fuel cell model including two water transport mechanisms in the membrane K Freiburg Germany A dynamic two-phase flow model for proton exchange mem- brane (PEM) fuel cells and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations

  1. Using beryllium-7 to assess cross-tropopause1 transport in global models2

    E-Print Network [OSTI]

    Liu, Hongyu

    1 Using beryllium-7 to assess cross-tropopause1 transport in global models2 3 Hongyu Liu1 , David B, MA13 14 Short Title: Beryllium-7 and cross-tropopause transport15 Index Terms: 0368 Troposphere Initiative (GMI) modeling framework the29 utility of cosmogenic beryllium-7 (7 Be), a natural aerosol tracer

  2. A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors

    E-Print Network [OSTI]

    Pietra, Paola

    A Mixed Finite-Element Discretization of the Energy-Transport Model for Semiconductors Stefan Holst #12;tting mixed #12;nite-element method is used to discretize the stationary energy. Energy-transport models describe the ow of electrons through a semi- conductor device, in uenced by di

  3. Addressing model bias and uncertainty in three dimensional groundwater transport forecasts for a physical aquifer experiment

    E-Print Network [OSTI]

    Vermont, University of

    Addressing model bias and uncertainty in three dimensional groundwater transport forecasts, and D. M. Rizzo (2008), Addressing model bias and uncertainty in three dimensional groundwater transport. Introduction [2] Eigbe et al. [1998] provide an excellent review of groundwater applications of the linear

  4. A unified model of electroporation and molecular transport

    E-Print Network [OSTI]

    Smith, Kyle Christopher

    2011-01-01T23:59:59.000Z

    Biological membranes form transient, conductive pores in response to elevated transmembrane voltage, a phenomenon termed electroporation. These pores facilitate electrical and molecular transport across cell membranes that ...

  5. Coupled Deterministic-Monte Carlo Transport for Radiation Portal Modeling

    SciTech Connect (OSTI)

    Smith, Leon E.; Miller, Erin A.; Wittman, Richard S.; Shaver, Mark W.

    2008-01-14T23:59:59.000Z

    Radiation portal monitors are being deployed, both domestically and internationally, to detect illicit movement of radiological materials concealed in cargo. Evaluation of the current and next generations of these radiation portal monitor (RPM) technologies is an ongoing process. 'Injection studies' that superimpose, computationally, the signature from threat materials onto empirical vehicle profiles collected at ports of entry, are often a component of the RPM evaluation process. However, measurement of realistic threat devices can be both expensive and time-consuming. Radiation transport methods that can predict the response of radiation detection sensors with high fidelity, and do so rapidly enough to allow the modeling of many different threat-source configurations, are a cornerstone of reliable evaluation results. Monte Carlo methods have been the primary tool of the detection community for these kinds of calculations, in no small part because they are particularly effective for calculating pulse-height spectra in gamma-ray spectrometers. However, computational times for problems with a high degree of scattering and absorption can be extremely long. Deterministic codes that discretize the transport in space, angle, and energy offer potential advantages in computational efficiency for these same kinds of problems, but the pulse-height calculations needed to predict gamma-ray spectrometer response are not readily accessible. These complementary strengths for radiation detection scenarios suggest that coupling Monte Carlo and deterministic methods could be beneficial in terms of computational efficiency. Pacific Northwest National Laboratory and its collaborators are developing a RAdiation Detection Scenario Analysis Toolbox (RADSAT) founded on this coupling approach. The deterministic core of RADSAT is Attila, a three-dimensional, tetrahedral-mesh code originally developed by Los Alamos National Laboratory, and since expanded and refined by Transpire, Inc. [1]. MCNP5 is used to calculate sensor pulse-height tallies. RADSAT methods, including adaptive, problem-specific energy-group creation, ray-effect mitigation strategies and the porting of deterministic angular flux to MCNP for individual particle creation are described in [2][3][4]. This paper discusses the application of RADSAT to the modeling of gamma-ray spectrometers in RPMs.

  6. DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE

    E-Print Network [OSTI]

    Aluko, Obanifemi

    2010-01-16T23:59:59.000Z

    . Otherwise, a rate-based mechanism is employed to describe the material and enrgy transfer between the liquid and vapor phases. The chemical reactions also introduce a structural difference between the models. Indeed, the chemical reactions can be either...

  7. A comparison between the fission matrix method, the diffusion model and the transport model

    SciTech Connect (OSTI)

    Dehaye, B.; Hugot, F. X.; Diop, C. M. [Commissariat a l'Energie Atomique et aux Energies Alternatives, Direction de l'Energie Nucleaire, Departement de Modelisation des Systemes et Structures, CEA DEN/DM2S, PC 57, F-91191 Gif-sur-Yvette cedex (France)

    2013-07-01T23:59:59.000Z

    The fission matrix method may be used to solve the critical eigenvalue problem in a Monte Carlo simulation. This method gives us access to the different eigenvalues and eigenvectors of the transport or fission operator. We propose to compare the results obtained via the fission matrix method with those of the diffusion model, and an approximated transport model. To do so, we choose to analyse the mono-kinetic and continuous energy cases for a Godiva-inspired critical sphere. The first five eigenvalues are computed with TRIPOLI-4{sup R} and compared to the theoretical ones. An extension of the notion of the extrapolation distance is proposed for the modes other than the fundamental one. (authors)

  8. Numerical Modeling of Reactive Multiphase Flow for FCC and Hot Gas Desulfurization Circulating Fluidized Beds

    SciTech Connect (OSTI)

    None

    2005-07-01T23:59:59.000Z

    This work was carried out to understand the behavior of the solid and gas phases in a CFB riser. Only the riser is modeled as a straight pipe. A model with linear algebraic approximation to solids viscosity of the form, {musubs} = 5.34{epsisubs}, ({espisubs} is the solids volume fraction) with an appropriate boundary condition at the wall obtained by approximate momentum balance solution at the wall to acount for the solids recirculation is tested against experimental results. The work done was to predict the flow patterns in the CFB risers from available experimental data, including data from a 7.5-cm-ID CFB riser at the Illinois Institute of Technology and data from a 20.0-cm-ID CFB riser at the Particulate Solid Research, Inc., facility. This research aims at modeling the removal of hydrogen sulfide from hot coal gas using zinc oxide as the sorbent in a circulating fluidized bed and in the process indentifying the parameters that affect the performance of the sulfidation reactor. Two different gas-solid reaction models, the unreacted shrinking core (USC) and the grain model were applied to take into account chemical reaction resistances. Also two different approaches were used to affect the hydrodynamics of the process streams. The first model takes into account the effect of micro-scale particle clustering by adjusting the gas-particle drag law and the second one assumes a turbulent core with pseudo-steady state boundary condition at the wall. A comparison is made with experimental results.

  9. Hybrid Car-Parrinello/Molecular Mechanics Modelling of Transition Metal Complexes: Structure, Dynamics and Reactivity

    E-Print Network [OSTI]

    Guidoni, Leonardo

    Hybrid Car-Parrinello/Molecular Mechanics Modelling of Transition Metal Complexes: Structure). We have recently developed a QM/MM extension of a Car-Parrinello scheme [5]. These hybrid Car functional theory embedded in a classical force field description. The power of such a combined Car

  10. REACTIVE FLOW IN VUGGY CARBONATES: METHODS AND MODELS APPLIED TO MATRIX ACIDIZING OF CARBONATES

    E-Print Network [OSTI]

    Izgec, Omer

    2010-07-14T23:59:59.000Z

    and its effect on fluid flow is numerical simulation. A 3D finite difference numerical model is developed based on Darcy-Brinkman formulation (DBF). Using the developed simulator a flow-based inversion approach is implemented to understand the connectivity...

  11. Penetration Deep into Tissues of Reactive Oxygen Species Generated in Floating-Electrode Dielectric Barrier Discharge (FE-DBD): in Vitro Agarose Gel Model Mimicking an Open Wound

    E-Print Network [OSTI]

    Dobrynin, Danil; Friedman, Gary; Fridman, Alexander

    2013-01-01T23:59:59.000Z

    In this manuscript we present an in vitro model based on agarose gel that can be used to simulate a dirty, oily, bloody, and morphologically complex surface of, for example, an open wound. We show this models effectiveness in simulating depth of penetration of reactive species generated in plasma deep into tissue of a rat and confirm the penetration depths with agarose gel model. We envision that in the future such a model could be used to study plasma discharges (and other modalities) and minimize the use of live animals: plasma can be optimized on the agarose gel wound model and then finally verified using an actual wound.

  12. A turbulent transport network model in MULTIFLUX coupled with TOUGH2

    SciTech Connect (OSTI)

    Danko, G.; Bahrami, D.; Birkholzer, J.T.

    2011-02-15T23:59:59.000Z

    A new numerical method is described for the fully iterated, conjugate solution of two discrete submodels, involving (a) a transport network model for heat, moisture, and airflows in a high-permeability, air-filled cavity; and (b) a variably saturated fractured porous medium. The transport network submodel is an integrated-parameter, computational fluid dynamics solver, describing the thermal-hydrologic transport processes in the flow channel system of the cavity with laminar or turbulent flow and convective heat and mass transport, using MULTIFLUX. The porous medium submodel, using TOUGH2, is a solver for the heat and mass transport in the fractured rock mass. The new model solution extends the application fields of TOUGH2 by integrating it with turbulent flow and transport in a discrete flow network system. We present demonstrational results for a nuclear waste repository application at Yucca Mountain with the most realistic model assumptions and input parameters including the geometrical layout of the nuclear spent fuel and waste with variable heat load for the individual containers. The MULTIFLUX and TOUGH2 model elements are fully iterated, applying a programmed reprocessing of the Numerical Transport Code Functionalization model-element in an automated Outside Balance Iteration loop. The natural, convective airflow field and the heat and mass transport in a representative emplacement drift during postclosure are explicitly solved in the new model. The results demonstrate that the direction and magnitude of the air circulation patterns and all transport modes are strongly affected by the heat and moisture transport processes in the surrounding rock, justifying the need for a coupled, fully iterated model solution such as the one presented in the paper.

  13. Analytical modeling of contaminant transport and horizontal well hydraulics

    E-Print Network [OSTI]

    Park, Eungyu

    2004-09-30T23:59:59.000Z

    transport from one-, two-, and three-dimensional finite sources in a finite-thickness aquifer using Green's function method. A library of unpublished analytical solutions with different finite source geometry is provided. A graphically integrated software...

  14. Analytical modeling of contaminant transport and horizontal well hydraulics 

    E-Print Network [OSTI]

    Park, Eungyu

    2004-09-30T23:59:59.000Z

    This dissertation is composed of three parts of major contributions. In Chapter II, we discuss analytical study of contaminant transport from a finite source in a finite-thickness aquifer. This chapter provides analytical solutions of contaminant...

  15. E-model for Transportation Problem of Linear Stochastic Fractional ...

    E-Print Network [OSTI]

    Dr.V.Charles

    2007-03-07T23:59:59.000Z

    Abstract: This paper deals with the so-called transportation problem of linear stochastic fractional programming, and ... sophisticated analysis. Stochastic ... circuit board of multi-objective LSFP, algorithm to identify redundant fractional objective ...

  16. Theoretical Description of Heavy Impurity Transport and its Application to the Modelling of Tungsten in JET and ASDEX Upgrade

    E-Print Network [OSTI]

    Theoretical Description of Heavy Impurity Transport and its Application to the Modelling of Tungsten in JET and ASDEX Upgrade

  17. A SCOPING STUDY: Development of Probabilistic Risk Assessment Models for Reactivity Insertion Accidents During Shutdown In U.S. Commercial Light Water Reactors

    SciTech Connect (OSTI)

    S. Khericha

    2011-06-01T23:59:59.000Z

    This report documents the scoping study of developing generic simplified fuel damage risk models for quantitative analysis from inadvertent reactivity insertion events during shutdown (SD) in light water pressurized and boiling water reactors. In the past, nuclear fuel reactivity accidents have been analyzed both mainly deterministically and probabilistically for at-power and SD operations of nuclear power plants (NPPs). Since then, many NPPs had power up-rates and longer refueling intervals, which resulted in fuel configurations that may potentially respond differently (in an undesirable way) to reactivity accidents. Also, as shown in a recent event, several inadvertent operator actions caused potential nuclear fuel reactivity insertion accident during SD operations. The set inadvertent operator actions are likely to be plant- and operation-state specific and could lead to accident sequences. This study is an outcome of the concern which arose after the inadvertent withdrawal of control rods at Dresden Unit 3 in 2008 due to operator actions in the plant inadvertently three control rods were withdrawn from the reactor without knowledge of the main control room operator. The purpose of this Standardized Plant Analysis Risk (SPAR) Model development project is to develop simplified SPAR Models that can be used by staff analysts to perform risk analyses of operating events and/or conditions occurring during SD operation. These types of accident scenarios are dominated by the operator actions, (e.g., misalignment of valves, failure to follow procedures and errors of commissions). Human error probabilities specific to this model were assessed using the methodology developed for SPAR model human error evaluations. The event trees, fault trees, basic event data and data sources for the model are provided in the report. The end state is defined as the reactor becomes critical. The scoping study includes a brief literature search/review of historical events, developments of a small set of comprehensive event trees and fault trees and recommendation for future work.

  18. Modeling electronic structure and transport properties of graphene with resonant scattering centers

    E-Print Network [OSTI]

    Modeling electronic structure and transport properties of graphene with resonant scattering centers present a detailed numerical study of the electronic properties of single-layer graphene with resonant and transport properties of functionalized graphene in a broad range of concentration of impurities from

  19. Proton transport model in the ionosphere. 2. Inuence of magnetic mirroring and collisions

    E-Print Network [OSTI]

    Lummerzheim, Dirk

    Proton transport model in the ionosphere. 2. In¯uence of magnetic mirroring and collisions on the angular redistribution in a proton beam M. Galand1 , J. Lilensten2 , W. Kofman2 , D. Lummerzheim3 1 High in a proton/hydrogen beam by using a transport code in comparison with observations. H-emission Doppler pro

  20. Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water

    E-Print Network [OSTI]

    Kurganov, Alexander

    Finite-Volume-Particle Methods for Models of Transport of Pollutant in Shallow Water Alina Chertock of shallow water equations and the pollutant propagation is described by a transport equation. The idea and the pollution computations: the shallow water equations are numerically integrated using a #12;nite- volume

  1. Rattling and freezing in a 1-D transport model Jean-Pierre Eckmann1

    E-Print Network [OSTI]

    Rattling and freezing in a 1-D transport model Jean-Pierre Eckmann1 and Lai-Sang Young2 1 D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 Transport in the chain 8 3.1 Single-particle dynamics energy and fluxes as functions of (and time) . . . . . . . . . . . 14 4 Freezing 16 4.1 Distribution

  2. Modeling Transport E ects on Ground-Level Ozone Using a

    E-Print Network [OSTI]

    Huang, Su-Yun

    Modeling Transport E ects on Ground-Level Ozone Using a Non-Stationary Space-Time Model Hsin on Ground-Level Ozone 1 #12;Summary This article presents a novel autoregressive space-time model for ground-level ozone data, which models not only spatio-temporal dynamics of hourly ozone con- centrations, but also

  3. Oceanic transports of heat and salt from a global model and data

    E-Print Network [OSTI]

    Olson, Elise

    2006-01-01T23:59:59.000Z

    A state estimate produced by ECCO-GODAE from a global one-degree model and data spanning the years 1992-2005 is analyzed in terms of transports of volume, temperature, and freshwater. The estimate is assessed to be ...

  4. Technology detail in a multi-sector CGE model : transport under climate policy

    E-Print Network [OSTI]

    Schafer, Andreas.

    A set of three analytical models is used to study the imbedding of specific transport technologies within a multi-sector, multi-region evaluation of constraints on greenhouse emissions. Key parameters of a computable general ...

  5. Geophysical constraints on contaminant transport modeling in a heterogeneous fluvial aquifer

    E-Print Network [OSTI]

    Zheng, Chunmiao

    Geophysical constraints on contaminant transport modeling in a heterogeneous fluvial aquifer Jerry the geophysically derived hydraulic conductivity representation in numerical simulations of the natural the effectiveness of geophysically derived and flowmeter based representations of the hydraulic conductivity field

  6. Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model

    E-Print Network [OSTI]

    Link, Percy Anne

    2008-01-01T23:59:59.000Z

    Several regional-scale ecosystem models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, ...

  7. Underground Test Area Subproject Phase I Data Analysis Task. Volume VII - Tritium Transport Model Documentation Package

    SciTech Connect (OSTI)

    None

    1996-12-01T23:59:59.000Z

    Volume VII of the documentation for the Phase I Data Analysis Task performed in support of the current Regional Flow Model, Transport Model, and Risk Assessment for the Nevada Test Site Underground Test Area Subproject contains the tritium transport model documentation. Because of the size and complexity of the model area, a considerable quantity of data was collected and analyzed in support of the modeling efforts. The data analysis task was consequently broken into eight subtasks, and descriptions of each subtask's activities are contained in one of the eight volumes that comprise the Phase I Data Analysis Documentation.

  8. Transport parameter determination and modeling of sodium and strontium plumes at the Idaho National Engineering Laboratory

    E-Print Network [OSTI]

    Londergan, John Thomas

    1987-01-01T23:59:59.000Z

    TRANSPORT PARAMETER DETERMINATION AND MODELING OF SODIUM AND STRONTIUM PLUMES AT THE IDAHO NATIONAL ENGINEERING LABORATORY A Thesis by JOHN THOMAS LONDERGAN Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject: Geophysics TRANSPORT PARAMETER DETERMINATION AND MODELING OF SODIUM AND STRONTIUM PLUMES AT THE IDAHO NATIONAL ENGINEERING LABORATORY A Thesis by JOHN THOMAS LONDERGAN Approved...

  9. Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents

    SciTech Connect (OSTI)

    Ellison, P.G.; Monson, P.R. (Westinghouse Savannah River Co., Aiken, SC (United States)); Mitchell, H.A. (Concord Associates, Inc., Knoxville, TN (United States))

    1990-01-01T23:59:59.000Z

    This paper describes in the needs and requirements to properly and efficiently model fission product transport on full scope reactor simulators. Current LWR simulators can be easily adapted to model severe accident phenomena and the transport of radionuclides. Once adapted these simulators can be used as a training tool during operator training exercises for training on severe accident guidelines, for training on containment venting procedures, or as training tool during site wide emergency training exercises.

  10. Modeling requirements for full-scope reactor simulators of fission-product transport during severe accidents

    SciTech Connect (OSTI)

    Ellison, P.G.; Monson, P.R. [Westinghouse Savannah River Co., Aiken, SC (United States); Mitchell, H.A. [Concord Associates, Inc., Knoxville, TN (United States)

    1990-12-31T23:59:59.000Z

    This paper describes in the needs and requirements to properly and efficiently model fission product transport on full scope reactor simulators. Current LWR simulators can be easily adapted to model severe accident phenomena and the transport of radionuclides. Once adapted these simulators can be used as a training tool during operator training exercises for training on severe accident guidelines, for training on containment venting procedures, or as training tool during site wide emergency training exercises.

  11. Conventional Transportation Planning Models: Review and Prospects for Alternatives

    E-Print Network [OSTI]

    Nagurney, Anna

    of 1964 ($ 375 m) Highway Oriented 1970s Oil Crisis, Back to the City Transit Oriented (Urban Mass-Aid Highway Act of 1956) 1960s Fiscal Crisis, Urban Exodus Suburbanization Urban Mass Transportation Act-Private Partnership 1990s Global Warming CAAA 1990, ISTEA 1991, TEA21 1998 2000s Alternative Energy Sources Terrorism

  12. A MODEL FOR THE FLEET SIZING OF DEMAND RESPONSIVE TRANSPORTATION SERVICES WITH TIME WINDOWS

    E-Print Network [OSTI]

    Dessouky, Maged

    A MODEL FOR THE FLEET SIZING OF DEMAND RESPONSIVE TRANSPORTATION SERVICES WITH TIME WINDOWS Marco a demand responsive transit service with a predetermined quality for the user in terms of waiting time models; Continuous approximation models; Paratransit services; Demand responsive transit systems. #12;3 1

  13. Estimates for temperature in projectile like fragment in geometric and transport models

    E-Print Network [OSTI]

    Mallik, S; Chaudhuri, G

    2013-01-01T23:59:59.000Z

    Projectile like fragments emerging from heavy ion collision have an excitation energy which is often labeled by a temperature. This temperature was recently calculated using a geometric model. We expand the geometric model to include also dynamic effects using a transport model. The temperatures so deduced agree quite well with values of temperature needed to fit experimental data.

  14. Journal of Transportation Engineering Modelling Automobile Driver's Toll-Lane Choice Behaviour at a Toll Plaza

    E-Print Network [OSTI]

    Kundu, Debasis

    Journal of Transportation Engineering Modelling Automobile Driver's Toll-Lane Choice Behaviour at a Toll Plaza --Manuscript Draft-- Manuscript Number: TEENG-1181R3 Full Title: Modelling Automobile Driver to develop a random utility based discrete multinomial choice model for the behaviour of automobile drivers

  15. ESAIM: M2AN ESAIM: Mathematical Modelling and Numerical Analysis Vol. 41, No 6, 2007, pp. 9751000 www.esaim-m2an.org

    E-Print Network [OSTI]

    Herbin, Raphaèle

    . Therefore, any modeling attempt of this zone should use reactive transport codes taking into account (ANDRA) and the French Electricity Producer (EDF) are jointly developing the software platform Alliances [24, 27]. This offers the possibility of designing coupling algorithms for reactive transport

  16. Modeling Water and Solute Transport in Porous Media: Theory and Application Modeling Water and Solute Transport in Porous Media: Theory

    E-Print Network [OSTI]

    Zhan, Hongbin

    and transport near horizontal wells, hydraulics of flowing horizontal wells, fresh water/sea water upconing and fractured media, and hydrogeophysics. He is an associate editor of some well-know journal such as Water Resources Research, Advances in Water Resources, and Journal of contaminant Hydrology. Chunmiao Zheng

  17. Atmospheric transport and dispersion modeling for the Hanford Environmental Dose Reconstruction Project

    SciTech Connect (OSTI)

    Ramsdell, J.V.

    1991-07-01T23:59:59.000Z

    Radiation doses that may have resulted from operations at the Hanford Site are being estimated in the Hanford Environmental Dose Reconstruction (HEDR) Project. One of the project subtasks, atmospheric transport, is responsible for estimating the transport, diffusion and deposition of radionuclides released to the atmosphere. This report discusses modeling transport and diffusion in the atmospheric pathway. It is divided into three major sections. The first section of the report presents the atmospheric modeling approach selected following discussion with the Technical Steering Panel that directs the HEDR Project. In addition, the section discusses the selection of the MESOI/MESORAD suite of atmospheric dispersion models that form the basis for initial calculations and future model development. The second section of the report describes alternative modeling approaches that were considered. Emphasis is placed on the family of plume and puff models that are based on Gaussian solution to the diffusion equations. The final portion of the section describes the performance of various models. The third section of the report discusses factors that bear on the selection of an atmospheric transport modeling approach for HEDR. These factors, which include the physical setting of the Hanford Site and the available meteorological data, serve as constraints on model selection. Five appendices are included in the report. 39 refs., 4 figs., 2 tabs.

  18. Transport enhancement and suppression in turbulent magnetic reconnection: A self-consistent turbulence model

    SciTech Connect (OSTI)

    Yokoi, N. [Institute of Industrial Science, University of Tokyo, Tokyo (Japan)] [Institute of Industrial Science, University of Tokyo, Tokyo (Japan); Higashimori, K.; Hoshino, M. [Department of Earth and Planetary Science, University of Tokyo, Tokyo (Japan)] [Department of Earth and Planetary Science, University of Tokyo, Tokyo (Japan)

    2013-12-15T23:59:59.000Z

    Through the enhancement of transport, turbulence is expected to contribute to the fast reconnection. However, the effects of turbulence are not so straightforward. In addition to the enhancement of transport, turbulence under some environment shows effects that suppress the transport. In the presence of turbulent cross helicity, such dynamic balance between the transport enhancement and suppression occurs. As this result of dynamic balance, the region of effective enhanced magnetic diffusivity is confined to a narrow region, leading to the fast reconnection. In order to confirm this idea, a self-consistent turbulence model for the magnetic reconnection is proposed. With the aid of numerical simulations where turbulence effects are incorporated in a consistent manner through the turbulence model, the dynamic balance in the turbulence magnetic reconnection is confirmed.

  19. Modeling electron transport in the presence of electric and magnetic fields.

    SciTech Connect (OSTI)

    Fan, Wesley C.; Drumm, Clifton Russell; Pautz, Shawn D.; Turner, C. David

    2013-09-01T23:59:59.000Z

    This report describes the theoretical background on modeling electron transport in the presence of electric and magnetic fields by incorporating the effects of the Lorentz force on electron motion into the Boltzmann transport equation. Electromagnetic fields alter the electron energy and trajectory continuously, and these effects can be characterized mathematically by differential operators in terms of electron energy and direction. Numerical solution techniques, based on the discrete-ordinates and finite-element methods, are developed and implemented in an existing radiation transport code, SCEPTRE.

  20. Uncertainty quantication in environmental flow and transport models

    E-Print Network [OSTI]

    Wang, Peng

    2011-01-01T23:59:59.000Z

    78] V. P. Singh, Kinematic Wave Modeling in Water Resources:V. P. Singh, “Kinematic wave modeling in water resources: awater content ? and precipitation rate, whose motion can be approximated using kinematic wave

  1. Analytical modelling of hydrogen transport in reactor containments

    E-Print Network [OSTI]

    Manno, V.

    1983-01-01T23:59:59.000Z

    There are two diffusion processes, molecular and turbulent, which should be modelled in different ways. Molecular diffusion is modelled by Wilke's formula for the multi-component gas diffusion, where the diffusion constants ...

  2. Ris-R-1201(EN) Radon Transport Modelling

    E-Print Network [OSTI]

    is a numerical computer model of soil-gas and radon trans- port in porous media. It can be used, for example radon exhalation from building materials such as concrete. The finite-volume model is a technical

  3. Guidance Document Reactive Chemicals

    E-Print Network [OSTI]

    showers and chillers. Health Hazards: The reactive chemicals are grouped primarily because of the physical

  4. Observations and models of heat and salt transport at a deepwater Gulf of Mexico vent

    E-Print Network [OSTI]

    Yang, Zong-Liang

    Observations and models of heat and salt transport at a deepwater Gulf of Mexico vent Andrew Smith salinity and temperature anomalies at a deepwater Gulf of Mexico vent in lease blocks MC852/853. In our method for estimating gas and water flux from vents. Our model indicates that vents in the Gulf of Mexico

  5. Finite-element discretization of a linearized 2 -D model for lubricated oil transportation

    E-Print Network [OSTI]

    Frey, Pascal

    Finite-element discretization of a linearized 2 - D model for lubricated oil transportation V acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy

  6. Revised rail-stop exposure model for incident-free transport of nuclear waste

    SciTech Connect (OSTI)

    Ostmeyer, R.M.

    1986-02-01T23:59:59.000Z

    This report documents a model for estimating railstop doses that occur during incident-free transport of nuclear waste by rail. The model, which has been incorporated into the RADTRAN III risk assessment code, can be applied to general freight and dedicated train shipments of waste.

  7. Fluid transport in branched structures with temporary closures: A model for quasistatic lung inflation

    E-Print Network [OSTI]

    Alencar, Adriano Mesquita

    Fluid transport in branched structures with temporary closures: A model for quasistatic lung a model system relevant to the inflation of a mammalian lung, an asymmetric bifurcating structure description of the underlying branching structure of the lung, by analyzing experimental pressure-volume data

  8. Mulitdimensional reactive transport modeling of CO2 minreal sequestration in basalts at the Helllisheidi geothermal field, Iceland

    E-Print Network [OSTI]

    Aradottir, E.S.P.

    2013-01-01T23:59:59.000Z

    geothermal power plant. In simulations of the pilot CO 2simulation of a 10 year full-scale CO 2 injection from Hellisheidi power plant. (

  9. Comparing FRACHEM and TOUGHREACT for reactive transport modeling of brine-rock interactions in enhanced geothermal systems (EGS)

    E-Print Network [OSTI]

    Andre, L.; Spycher, N.; Xu, T.; Pruess, K.; Vuataz, F.-D.

    2008-01-01T23:59:59.000Z

    of the Soultz fractured reservoir. Proceedings EHDRAthrough a deep fractured reservoir. Different studies (Hot Fractured Rock system: comparison of two reservoirs at

  10. Estimating Reaction Rate Coefficients Within a Travel-Time Modeling Framework

    SciTech Connect (OSTI)

    Gong, R [Georgia Institute of Technology; Lu, C [Georgia Institute of Technology; Luo, Jian [Georgia Institute of Technology; Wu, Wei-min [Stanford University; Cheng, H. [Stanford University; Criddle, Craig [Stanford University; Kitanidis, Peter K. [Stanford University; Gu, Baohua [ORNL; Watson, David B [ORNL; Jardine, Philip M [ORNL; Brooks, Scott C [ORNL

    2011-03-01T23:59:59.000Z

    A generalized, efficient, and practical approach based on the travel-time modeling framework is developed to estimate in situ reaction rate coefficients for groundwater remediation in heterogeneous aquifers. The required information for this approach can be obtained by conducting tracer tests with injection of a mixture of conservative and reactive tracers and measurements of both breakthrough curves (BTCs). The conservative BTC is used to infer the travel-time distribution from the injection point to the observation point. For advection-dominant reactive transport with well-mixed reactive species and a constant travel-time distribution, the reactive BTC is obtained by integrating the solutions to advective-reactive transport over the entire travel-time distribution, and then is used in optimization to determine the in situ reaction rate coefficients. By directly working on the conservative and reactive BTCs, this approach avoids costly aquifer characterization and improves the estimation for transport in heterogeneous aquifers which may not be sufficiently described by traditional mechanistic transport models with constant transport parameters. Simplified schemes are proposed for reactive transport with zero-, first-, nth-order, and Michaelis-Menten reactions. The proposed approach is validated by a reactive transport case in a two-dimensional synthetic heterogeneous aquifer and a field-scale bioremediation experiment conducted at Oak Ridge, Tennessee. The field application indicates that ethanol degradation for U(VI)-bioremediation is better approximated by zero-order reaction kinetics than first-order reaction kinetics.

  11. Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    SciTech Connect (OSTI)

    Drici, Warda

    2003-08-01T23:59:59.000Z

    This report documents the analysis of the available transport parameter data conducted in support of the development of a Corrective Action Unit (CAU) groundwater flow model for Central and Western Pahute Mesa: CAUs 101 and 102.

  12. Centrifuge modeling of LNAPL transport in partially saturated sand

    SciTech Connect (OSTI)

    Esposito, G.; Allersma, H.G.B.; Selvadurai, A.P.S.

    1999-12-01T23:59:59.000Z

    Model tests were performed at the Geotechnical Centrifuge Facility of Delft University of Technology, The Netherlands, to examine the mechanics of light nonaqueous phase liquid (LNAPL) movement in a partially saturated porous granular medium. The experiment simulated a 2D spill of LNAPL in an unsaturated sand prepared at two values of porosity. The duration of the centrifuge model tests corresponded to a prototype equivalent of 110 days. The choice of modeling a 2D flow together with the use of a transparent container enabled direct visual observation of the experiments. Scaling laws developed in connection with other centrifuge modeling studies were used to support the test results. Tests were conducted at two different centrifuge accelerations to verify, by means of the modeling of models technique, the similitude between the different experiments. The paper presents details of the experimental methodologies and the measuring techniques used to evaluate the final distribution of water and LNAPL content in the soils.

  13. Constructing transportable behavioural models for nonlinear electronic devices

    E-Print Network [OSTI]

    David M. Walker; R. Brown; N. B. Tufillaro

    1998-10-09T23:59:59.000Z

    We use radial basis functions to model the input--output response of an electronic device. A new methodology for producing models that accuratly describe the response of the device over a wide range of operating points is introduced. A key to the success of the method is the ability to find a polynomial relationship between the model parameters and the operating points of the device.

  14. Revised Knudsen-layer reduction of fusion reactivity

    SciTech Connect (OSTI)

    Albright, B. J.; Molvig, Kim; Huang, C.-K.; Simakov, A. N.; Dodd, E. S.; Hoffman, N. M.; Kagan, G. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States); Schmit, P. F. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)] [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)

    2013-12-15T23:59:59.000Z

    Recent work by Molvig et al. [Phys. Rev. Lett. 109, 095001 (2012)] examined how fusion reactivity may be reduced from losses of fast ions in finite assemblies of fuel. In this paper, this problem is revisited with the addition of an asymptotic boundary-layer treatment of ion kinetic losses. This boundary solution, reminiscent of the classical Milne problem from linear transport theory, obtains a free-streaming limit of fast ion losses near the boundary, where the diffusion approximation is invalid. Thermonuclear reaction rates have been obtained for the ion distribution functions predicted by this improved model. It is found that while Molvig's “Knudsen distribution function” bounds from above the magnitude of the reactivity reduction, this more accurate treatment leads to less dramatic losses of tail ions and associated reduction of thermonuclear reaction rates for finite fuel volumes.

  15. Model Recovery Procedure for Response to a Radiological Transportation...

    Office of Environmental Management (EM)

    Incident.docx More Documents & Publications Hazardous Materials Incident Response Procedure First Responder Initial Response Procedure TEPP Model Needs Assessment Document...

  16. Conceptual model for transport processes in the Culebra Dolomite Member, Rustler Formation

    SciTech Connect (OSTI)

    Holt, R.M. [Holt Hydrogeology, Placitas, NM (United States)] [Holt Hydrogeology, Placitas, NM (United States)

    1997-08-01T23:59:59.000Z

    The Culebra Dolomite Member of the Rustler Formation represents a possible pathway for contaminants from the Waste Isolation Pilot Plant underground repository to the accessible environment. The geologic character of the Culebra is consistent with a double-porosity, multiple-rate model for transport in which the medium is conceptualized as consisting of advective porosity, where solutes are carried by the groundwater flow, and fracture-bounded zones of diffusive porosity, where solutes move through slow advection or diffusion. As the advective travel length or travel time increases, the nature of transport within a double-porosity medium changes. This behavior is important for chemical sorption, because the specific surface area per unit mass of the diffusive porosity is much greater than in the advective porosity. Culebra transport experiments conducted at two different length scales show behavior consistent with a multiple-rate, double-porosity conceptual model for Culebra transport. Tracer tests conducted on intact core samples from the Culebra show no evidence of significant diffusion, suggesting that at the core scale the Culebra can be modeled as a single-porosity medium where only the advective porosity participates in transport. Field tracer tests conducted in the Culebra show strong double-porosity behavior that is best explained using a multiple-rate model.

  17. Conceptual model for regional radionuclide transport from a salt dome repository: a technical memorandum

    SciTech Connect (OSTI)

    Kier, R.S.; Showalter, P.A.; Dettinger, M.D.

    1980-05-30T23:59:59.000Z

    Disposal of high-level radioactive wastes is a major environmental problem influencing further development of nuclear energy in this country. Salt domes in the Gulf Coast Basin are being investigated as repository sites. A major concern is geologic and hydrologic stability of candidate domes and potential transport of radionuclides by groundwater to the biosphere prior to their degradation to harmless levels of activity. This report conceptualizes a regional geohydrologic model for transport of radionuclides from a salt dome repository. The model considers transport pathways and the physical and chemical changes that would occur through time prior to the radionuclides reaching the biosphere. Necessary, but unknown inputs to the regional model involve entry and movement of fluids through the repository dome and across the dome-country rock interface and the effect on the dome and surrounding strata of heat generated by the radioactive wastes.

  18. Analytical solutions for benchmarking cold regions subsurface water flow and energy transport models: One-dimensional soil thaw

    E-Print Network [OSTI]

    McKenzie, Jeffrey M.

    Analytical solutions for benchmarking cold regions subsurface water flow and energy transport Freezing and thawing a b s t r a c t Numerous cold regions water flow and energy transport models have of powerful simulators of cold regions subsurface water flow and energy transport have emerged in recent years

  19. Sensitivity of water mass transformation and heat transport to subgridscale mixing in coarse-resolution ocean models

    E-Print Network [OSTI]

    Gnanadesikan, Anand

    colleagues suggests that without this heat transport the globe would freeze over, [Winton, 2003Sensitivity of water mass transformation and heat transport to subgridscale mixing in coarse of subgridscale mixing on ocean heat transport in coarse- resolution ocean models of the type used in coupled

  20. A Generalized Linear Transport Model for Spatially-Correlated Stochastic Media

    E-Print Network [OSTI]

    Anthony B. Davis; Feng Xu

    2014-10-29T23:59:59.000Z

    We formulate a new model for transport in stochastic media with long-range spatial correlations where exponential attenuation (controlling the propagation part of the transport) becomes power law. Direct transmission over optical distance $\\tau(s)$, for fixed physical distance $s$, thus becomes $(1+\\tau(s)/a)^{-a}$, with standard exponential decay recovered when $a\\to\\infty$. Atmospheric turbulence phenomenology for fluctuating optical properties rationalizes this switch. Foundational equations for this generalized transport model are stated in integral form for $d=1,2,3$ spatial dimensions. A deterministic numerical solution is developed in $d=1$ using Markov Chain formalism, verified with Monte Carlo, and used to investigate internal radiation fields. Standard two-stream theory, where diffusion is exact, is recovered when $a=\\infty$. Differential diffusion equations are not presently known when $a<\\infty$, nor is the integro-differential form of the generalized transport equation. Monte Carlo simulations are performed in $d=2$, as a model for transport on random surfaces, to explore scaling behavior of transmittance $T$ when transport optical thickness $\\tau_\\text{t} \\gg 1$. Random walk theory correctly predicts $T \\propto \\tau_\\text{t}^{-\\min\\{1,a/2\\}}$ in the absence of absorption. Finally, single scattering theory in $d=3$ highlights the model's violation of angular reciprocity when $a<\\infty$, a desirable property at least in atmospheric applications. This violation is traced back to a key trait of generalized transport theory, namely, that we must distinguish more carefully between two kinds of propagation: one that ends in a virtual or actual detection, the other in a transition from one position to another in the medium.

  1. Simplified 1-D Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects

    E-Print Network [OSTI]

    Fleenor, William E.; Bombardelli, Fabian

    2013-01-01T23:59:59.000Z

    Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquinhydrodynamic and salinity transport mod- eling of the Sacramento–San Joaquin

  2. Event simulations in a transport model for intermediate energy heavy ion collisions: Applications to multiplicity distributions

    E-Print Network [OSTI]

    Mallik, S; Chaudhuri, G

    2015-01-01T23:59:59.000Z

    We perform transport model calculations for central collisions of mass 120 on mass 120 at laboratory beam energy in the range 20 MeV/nucleon to 200 MeV/nucleon. A simplified yet accurate method allows calculation of fluctuations in systems much larger than what was considered feasible in a well-known and already existing model. The calculations produce clusters. The distribution of clusters is remarkably similar to that obtained in equilibrium statistical model.

  3. Event simulations in a transport model for intermediate energy heavy ion collisions: Applications to multiplicity distributions

    E-Print Network [OSTI]

    S. Mallik; S. Das Gupta; G. Chaudhuri

    2015-03-19T23:59:59.000Z

    We perform transport model calculations for central collisions of mass 120 on mass 120 at laboratory beam energy in the range 20 MeV/nucleon to 200 MeV/nucleon. A simplified yet accurate method allows calculation of fluctuations in systems much larger than what was considered feasible in a well-known and already existing model. The calculations produce clusters. The distribution of clusters is remarkably similar to that obtained in equilibrium statistical model.

  4. Heat Transport in Groundwater Systems--Finite Element Model

    E-Print Network [OSTI]

    Grubaugh, E. K.; Reddell, D. L.

    into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...

  5. Modeling of Transport in Lithium Ion Battery Electrodes

    E-Print Network [OSTI]

    Martin, Michael

    2012-07-16T23:59:59.000Z

    to model the solid state diffusion behavior in several generated electrode morphologies. Developed computational codes were used to generate targeted structures under prescribed conditions of particle shape, size, and overall morphology. The diffusion...

  6. Comprehensive computer model for magnetron sputtering. II. Charged particle transport

    SciTech Connect (OSTI)

    Jimenez, Francisco J., E-mail: fjimenez@ualberta.ca; Dew, Steven K. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada); Field, David J. [Smith and Nephew (Alberta) Inc., Fort Saskatchewan T8L 4K4 (Canada)

    2014-11-01T23:59:59.000Z

    Discharges for magnetron sputter thin film deposition systems involve complex plasmas that are sensitively dependent on magnetic field configuration and strength, working gas species and pressure, chamber geometry, and discharge power. The authors present a numerical formulation for the general solution of these plasmas as a component of a comprehensive simulation capability for planar magnetron sputtering. This is an extensible, fully three-dimensional model supporting realistic magnetic fields and is self-consistently solvable on a desktop computer. The plasma model features a hybrid approach involving a Monte Carlo treatment of energetic electrons and ions, along with a coupled fluid model for thermalized particles. Validation against a well-known one-dimensional system is presented. Various strategies for improving numerical stability are investigated as is the sensitivity of the solution to various model and process parameters. In particular, the effect of magnetic field, argon gas pressure, and discharge power are studied.

  7. Heat Transport in Groundwater Systems--Finite Element Model 

    E-Print Network [OSTI]

    Grubaugh, E. K.; Reddell, D. L.

    1980-01-01T23:59:59.000Z

    into groundwater aquifers for long term energy storage. Analytical solutions are available that predict water temperatures as hot water is injected into a groundwater aquifer, but little field and laboratory data are available to verify these models. The objectives...

  8. Thermalization at lowest energies? A view from a transport model

    E-Print Network [OSTI]

    C Hartnack; H Oeschler; J Aichelin

    2010-10-05T23:59:59.000Z

    Using the Isospin Quantum Molecular Dynamics (IQMD) model we analyzed the production of pions and kaons in the energy range of 1-2 AGeV in order to study the question why thermal models could achieve a successful description. For this purpose we study the variation of pion and kaon yields using different elementary cross sections. We show that several ratios appear to be rather robust versus their variations.

  9. Radiation transport modeling using extended quadrature method of moments

    SciTech Connect (OSTI)

    Vikas, V., E-mail: vvikas@iastate.edu [Department of Aerospace Engineering, 2271 Howe Hall, Iowa State University, Ames, IA 50011 (United States); Hauck, C.D., E-mail: hauckc@ornl.gov [Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Wang, Z.J., E-mail: zjw@ku.edu [Department of Aerospace Engineering, 2120 Learned Hall, University of Kansas, Lawrence, KS 66045 (United States); Fox, R.O., E-mail: rofox@iastate.edu [Department of Chemical and Biological Engineering, 2114 Sweeney Hall, Iowa State University, Ames, IA 50011 (United States)

    2013-08-01T23:59:59.000Z

    The radiative transfer equation describes the propagation of radiation through a material medium. While it provides a highly accurate description of the radiation field, the large phase space on which the equation is defined makes it numerically challenging. As a consequence, significant effort has gone into the development of accurate approximation methods. Recently, an extended quadrature method of moments (EQMOM) has been developed to solve univariate population balance equations, which also have a large phase space and thus face similar computational challenges. The distinct advantage of the EQMOM approach over other moment methods is that it generates moment equations that are consistent with a positive phase space density and has a moment inversion algorithm that is fast and efficient. The goal of the current paper is to present the EQMOM method in the context of radiation transport, to discuss advantages and disadvantages, and to demonstrate its performance on a set of standard one-dimensional benchmark problems that encompass optically thin, thick, and transition regimes. Special attention is given in the implementation to the issue of realizability—that is, consistency with a positive phase space density. Numerical results in one dimension are promising and lay the foundation for extending the same framework to multiple dimensions.

  10. Transported PDF Modeling of Nonpremixed Turbulent CO/H-2/N-2 Jet Flames

    SciTech Connect (OSTI)

    Zhao, xinyu; Haworth, D. C.; Huckaby, E. David

    2012-01-01T23:59:59.000Z

    Turbulent CO/H{sub 2}/N{sub 2} (“syngas”) flames are simulated using a transported composition probability density function (PDF) method. A consistent hybrid Lagrangian particle/Eulerian mesh algorithm is used to solve the modeled PDF transport equation. The model includes standard k–? turbulence, gradient transport for scalars, and Euclidean minimum spanning tree (EMST) mixing. Sensitivities of model results to variations in the turbulence model, the treatment of radiation heat transfer, the choice of chemical mechanism, and the PDF mixing model are explored. A baseline model reproduces the measured mean and rms temperature, major species, and minor species profiles reasonably well, and captures the scaling that is observed in the experiments. Both our results and the literature suggest that further improvements can be realized with adjustments in the turbulence model, the radiation heat transfer model, and the chemical mechanism. Although radiation effects are relatively small in these flames, consideration of radiation is important for accurate NO prediction. Chemical mechanisms that have been developed specifically for fuels with high concentrations of CO and H{sub 2} perform better than a methane mechanism that was not designed for this purpose. It is important to account explicitly for turbulence–chemistry interactions, although the details of the mixing model do not make a large difference in the results, within reasonable limits.

  11. GREET 1.5 - transportation fuel-cycle model - Vol. 1 : methodology, development, use, and results.

    SciTech Connect (OSTI)

    Wang, M. Q.

    1999-10-06T23:59:59.000Z

    This report documents the development and use of the most recent version (Version 1.5) of the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The model, developed in a spreadsheet format, estimates the full fuel-cycle emissions and energy associated with various transportation fuels and advanced vehicle technologies for light-duty vehicles. The model calculates fuel-cycle emissions of five criteria pollutants (volatile organic compounds, carbon monoxide, nitrogen oxides, particulate matter with diameters of 10 micrometers or less, and sulfur oxides) and three greenhouse gases (carbon dioxide, methane, and nitrous oxide). The model also calculates total energy consumption, fossil fuel consumption, and petroleum consumption when various transportation fuels are used. The GREET model includes the following cycles: petroleum to conventional gasoline, reformulated gasoline, conventional diesel, reformulated diesel, liquefied petroleum gas, and electricity via residual oil; natural gas to compressed natural gas, liquefied natural gas, liquefied petroleum gas, methanol, Fischer-Tropsch diesel, dimethyl ether, hydrogen, and electricity; coal to electricity; uranium to electricity; renewable energy (hydropower, solar energy, and wind) to electricity; corn, woody biomass, and herbaceous biomass to ethanol; soybeans to biodiesel; flared gas to methanol, dimethyl ether, and Fischer-Tropsch diesel; and landfill gases to methanol. This report also presents the results of the analysis of fuel-cycle energy use and emissions associated with alternative transportation fuels and advanced vehicle technologies to be applied to passenger cars and light-duty trucks.

  12. Hydrologic Nuclide Transport Models in Cyder, A Geologic Disposal Software Library - 13328

    SciTech Connect (OSTI)

    Huff, Kathryn D. [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL (United States)] [Argonne National Laboratory, 9700 S. Cass Ave, Argonne, IL (United States)

    2013-07-01T23:59:59.000Z

    Component level and system level abstraction of detailed computational geologic repository models have resulted in four rapid computational models of hydrologic radionuclide transport at varying levels of detail. Those models are described, as is their implementation in Cyder, a software library of interchangeable radionuclide transport models appropriate for representing natural and engineered barrier components of generic geology repository concepts. A proof of principle demonstration was also conducted in which these models were used to represent the natural and engineered barrier components of a repository concept in a reducing, homogenous, generic geology. This base case demonstrates integration of the Cyder open source library with the Cyclus computational fuel cycle systems analysis platform to facilitate calculation of repository performance metrics with respect to fuel cycle choices. (authors)

  13. A screening model for evaluating the degradation and transport of MTBE and other fuel oxygenates in the subsurface

    SciTech Connect (OSTI)

    Sun, Y; Lu, X

    2004-04-20T23:59:59.000Z

    Methyl tert-butyl ether (MTBE) has received high attention as it contributed to cleaner air and contaminated thousands of underground storage tank sites. Because MTBE is very water soluble, it is more difficult to remove from water by conventional remediation techniques. Therefore, biodegradation of MTBE has become a remediation alternative. In order to understand the transport and transformation processes, they present a closed form solution as a screening tool in this paper. The possible reaction pathways of first-order reactions are described as a reaction matrix. The singular value decomposition is conducted analytically to decouple the partial differential equations of the multi-species transport system coupled by the reaction matrix into multiple independent subsystems. Therefore, the complexity of mathematical description for the reactive transport system is significantly reduced and analytical solutions may be previously available or easily derived.

  14. A fractional dispersion model for overland solute transport

    E-Print Network [OSTI]

    Deng, Zhi-Qiang; de Lima, M. Isabel P.; Singh, Vijay P.; de Lima, Jo??o L. M. P.

    2006-03-18T23:59:59.000Z

    . It is apparent from Figure 1 and the above-mentioned variance analysis that (1) the relationship between variance and time does not simply follow a power law, although approximate power-law relations may be found in some cases; and (2) a polynomial equation... with a variable power index can best describe the relation between vari- ance and time. These characteristics of the variance of observed concentration distributions are difficult to predict using existing integer-order models. In fact, the infinite...

  15. Holographic transports and stability in anisotropic linear axion model

    E-Print Network [OSTI]

    Xian-Hui Ge; Yi Ling; Chao Niu; Sang-Jin Sin

    2015-01-15T23:59:59.000Z

    We study thermoelectric conductivities and shear viscosities in a holographically anisotropic model. Momentum relaxation is realized through perturbing the linear axion field. AC conductivity exhibits a conherent/incoherent metal transition. The longitudinal shear viscosity for prolate anisotropy violates the bound conjectured by Kovtun-Son-Starinets. We also find that thermodynamic and dynamical instabilities are not always equivalent, which provides a counter example of the Gubser-Mitra conjecture.

  16. Transport Modeling Working Group Meeting Reports | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn'tOriginEducationVideoStrategic|IndustrialCenter Gets PeopleTransmissionModeling Working Group

  17. Modeling transport of disposed dredged material from placement sites in Grays Harbor, WA

    E-Print Network [OSTI]

    US Army Corps of Engineers

    Modeling transport of disposed dredged material from placement sites in Grays Harbor, WA E- to mid- term dredge material management strategies for the Federal Navigation Project at Grays Harbor dredging quantities. However, the most heavily used dredged material placement sites lie in proximity

  18. Controlling chaotic transport in a Hamiltonian model of interest to magnetized plasmas

    E-Print Network [OSTI]

    Guido Ciraolo; Cristel Chandre; Ricardo Lima; Michel Vittot; Marco Pettini; Charles Figarella; Philippe Ghendrih

    2004-02-25T23:59:59.000Z

    We present a technique to control chaos in Hamiltonian systems which are close to integrable. By adding a small and simple control term to the perturbation, the system becomes more regular than the original one. We apply this technique to a model that reproduces turbulent ExB drift and show numerically that the control is able to drastically reduce chaotic transport.

  19. Reduced Order Model Compensator Control of Species Transport in a CVD Reactor

    E-Print Network [OSTI]

    Reduced Order Model Compensator Control of Species Transport in a CVD Reactor G.M. Kepler, H for computation of feedback controls and compensators in a high pressure chemical vapor deposition (HPCVD) reactor University to design and build such a HPCVD reactor with real­time sensing and control as an innovative

  20. Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions

    E-Print Network [OSTI]

    Zhang, Liqing

    2011-07-01T23:59:59.000Z

    . . . . . . . . . . . . . . . . . . . . . 71 III.4.1. Factorial Design Experiment . . . . . . . . . . . . 72 III.4.2. Impact of System Parameters on Policy Values . . 73 III.5. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 IV EXACT MODELS AND OPTIMAL POLICIES FOR SHIP....3.1. Problem Formulation . . . . . . . . . . . . . . . . 93 IV.3.2. Exact Optimal Policy . . . . . . . . . . . . . . . . 95 IV.4. Common Carriage Transportation . . . . . . . . . . . . . 100 IV.4.1. Problem Formulation...

  1. A mixed finite-element scheme of a semiconductor energy-transport model

    E-Print Network [OSTI]

    Hanke-Bourgeois, Martin

    A mixed finite-element scheme of a semiconductor energy-transport model using dual entropy which are able to deal with physical effects such as carrier heating and velocity overshoot. The energy that the Joule heating term vanishes if the dual entropy variables w1 = (µ - V )/T and w2 = -1/T are employed

  2. MODELING TRITIUM TRANSPORT IN PBLI BREEDER BLANKETS UNDER STEADY STATE , M. Abdou1

    E-Print Network [OSTI]

    Abdou, Mohamed

    MODELING TRITIUM TRANSPORT IN PBLI BREEDER BLANKETS UNDER STEADY STATE H. Zhang1 , A. Ying1 , M breeder blankets under realistic reactor-like conditions in this paper. Tritium concentration. Tritium behavior in the liquid metal breeder blanket requires a thorough understanding of the sequence

  3. Transport Phenomena in Polymer Electrolyte Membranes II. Binary Friction Membrane Model

    E-Print Network [OSTI]

    Struchtrup, Henning

    is derived to represent conditions found in alternating current ac impedance conductivity measurements the conditions of ac impedance conductivity measurements. Using em- pirically fitted transport parameters dynamic models required for fundamental simulation of in situ processes that are difficult to ob- serve

  4. TESTS OF 1-D TRANSPORT MODELS, AND THEIR PREDICTIONS FOR ITER

    E-Print Network [OSTI]

    Vlad, Gregorio

    of Technology, Göteborg, Sweden Abstract A number of proposed tokamak thermal transport models are tested foundation for extrapolations of energy confinement scalings to the ITER regime, 2) a means for optimizing Profile Database [2] which contains fully analyzed profile data, readily accessible, specified

  5. User's manual for the Sandia Waste-Isolation Flow and Transport model (SWIFT).

    SciTech Connect (OSTI)

    Reeves, Mark; Cranwell, Robert M.

    1981-11-01T23:59:59.000Z

    This report describes a three-dimensional finite-difference model (SWIFT) which is used to simulate flow and transport processes in geologic media. The model was developed for use by the Nuclear Regulatory Commission in the analysis of deep geologic nuclear waste-disposal facilities. This document, as indicated by the title, is a user's manual and is intended to facilitate the use of the SWIFT simulator. Mathematical equations, submodels, application notes, and a description of the program itself are given herein. In addition, a complete input data guide is given along with several appendices which are helpful in setting up a data-input deck. Computer code SWIFT (Sandia Waste Isolation, Flow and Transport Model) is a fully transient, three-dimensional model which solves the coupled equations for transport in geologic media. The processes considered are: (1) fluid flow; (2) heat transport; (3) dominant-species miscible displacement; and (4) trace-species miscible displacement. The first three processes are coupled via fluid density and viscosity. Together they provide the velocity field on which the fourth process depends.

  6. A model of sediment resuspension and transport dynamics in southern Lake Michigan

    E-Print Network [OSTI]

    A model of sediment resuspension and transport dynamics in southern Lake Michigan Jing Lou and David J. Schwab NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan Dmitry Beletsky1 Department of Naval Architecture and Marine Engineering, University of Michigan, Ann Arbor Nathan Hawley NOAA

  7. Water Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing,

    E-Print Network [OSTI]

    Optimization J. Vernon Cole and Ashok Gidwani CFDRC Prepared for: DOE Hydrogen Fuel Cell Kickoff MeetingWater Transport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing, and Design fuel cell design and operation; Demonstrate improvements in water management resulting in improved

  8. A Lagrangian subgridscale model for particle transport improvement and application in the Adriatic Sea

    E-Print Network [OSTI]

    Ozgökmen, Tamay M.

    such as dispersion of pollutants, biological species, and sediments. Forecasting of the Lagrangian pathways of the dispersion of pollutants, biological species, and sediments. At the basis of such applications is the transA Lagrangian subgridscale model for particle transport improvement and application in the Adriatic

  9. COMSOL Modeling of Groundwater Flow and Contaminant Transport in Two-Dimensional Geometries With Heterogeneities

    E-Print Network [OSTI]

    Gobbert, Matthias K.

    COMSOL Modeling of Groundwater Flow and Contaminant Transport in Two-Dimensional Geometries, Environmental Sys- tems. 1 Introduction Groundwater contributes an large portion of stream flow and subsequently% of a streams nitrogen load has been discharged from groundwater. The surficial aquifer geometry in this area

  10. System for reactivating catalysts

    DOE Patents [OSTI]

    Ginosar, Daniel M. (Idaho Falls, ID); Thompson, David N. (Idaho Falls, ID); Anderson, Raymond P. (Idaho Falls, ID)

    2010-03-02T23:59:59.000Z

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  11. Transport and dispersion of pollutants in surface impoundments: a finite element model

    SciTech Connect (OSTI)

    Yeh, G.T.

    1980-07-01T23:59:59.000Z

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  12. Journal of Power Sources 164 (2007) 189195 Modeling water transport in liquid feed direct methanol fuel cells

    E-Print Network [OSTI]

    2007-01-01T23:59:59.000Z

    Journal of Power Sources 164 (2007) 189­195 Modeling water transport in liquid feed direct methanol management in direct methanol fuel cells (DMFCs) is very critical and complicated because of many interacting rights reserved. Keywords: Direct methanol fuel cell; Water transport; Mathematical modeling; Three

  13. The Ising model and critical behavior of transport in binary composite N. B. Murphy and K. M. Golden

    E-Print Network [OSTI]

    Golden, Kenneth M.

    nanotube composites,37 and sea ice.26,27 A key feature of these materials is the critical dependenceThe Ising model and critical behavior of transport in binary composite media N. B. Murphy and K. M) The Ising model and critical behavior of transport in binary composite media N. B. Murphy and K. M. Golden

  14. Transport-theoretic model for the electron-proton-hydrogen atom auroa. II. Model results

    SciTech Connect (OSTI)

    Strickland, D.J. [Computational Physics, Inc., Fairfax, VA (United States); Daniell, R.E. Jr. [Computational Physics, Inc., Newton, MA (United States); Basu, B. [Hanscom Air Force Base, MA (United States)] [and others

    1993-12-01T23:59:59.000Z

    In a companion paper, a self-consistent transport-theoretic model for the combined electron-proton-hydrogen atom aurora was described. In this paper, numberical results based on the model are presented. This is done for the pure electron aurora, the pure proton-hydrogen atom aurora, and finally for the combined aurora. Adopting commonly used types of energy distributions for the incident particle (electron and proton) fluxes, the authors give numerical solutions for the precipitating electron, proton, and hydrogen atom differential number fluxes. Results are also given for ionization yields and emission yields of the following features: N{sub 2}{sup +} first negative group (3914 {Angstrom}), N{sub 2} second positive group (3371 {Angstrom}), selected N{sub 2} Lyman-Birge-Hopfields bands (1325, 1354, 1383, 1493, and all bands between 1700 and 1800 {Angstrom}), O I (1356 {Angstrom}), L{sub {alpha}} (1216 {Angstrom}), H{sub {beta}} (4861 {Angstrom}), and H{sub {alpha}} (6563 {Angstrom}). The yield at 1493 {Angstrom} also contains a contribution from N I (1493 {Angstrom}), which in fact dominates LBH emission. A major new result of this study is that the secondary electron flux produced by the proton-hydrogen atom aurora is much softer than that produced by the electron aurora. This increased softness is due to the fact that (for energies of aurora interest) cross sections for secondary electron flux produced by the proton-hydrogen atom aurora is much softer than that produced by the electron aurora. This increased softness is due to the fact that (for energies of auroral interest) cross sections for secondary electron production by proton and hydrogen atom impact decrease exponentially with increasing secondary electron energy, whereas the cross sections for electron impact decrease as an inverse power law with increasing secondary energy.

  15. A critical view on transport and entanglement in models of photosynthesis

    E-Print Network [OSTI]

    Tiersch, Markus; Briegel, Hans J

    2011-01-01T23:59:59.000Z

    Quantum effects in biological light-harvesting molecules, such as quantum coherence of excitonic states and entanglement have recently gained much attention. We observe a certain discrepancy between the original experimental work and several theoretical treatments of coherent excitation transport in light-harvesting molecules. Contrary to what is generally stated, we argue that entanglement in such molecules is generally not equivalent to the presence of coherence but mostly introduced by initial assumptions underlying the models, and that entanglement, as opposite to coherence, seems to play no role in the transport efficiency.

  16. Application of canonical profiles transport model to the H-mode shots in tokamaks

    SciTech Connect (OSTI)

    Dnestrovskij, Yu. N.; Dnestrovskij, A. Yu.; Danilov, A. V.; Lysenko, S. E.; Cherkasov, S. V. [Institute of Tokamak Physics, Russian Research Centre Kurchatov Institute (Russian Federation); Gerasimov, S. N.; Hender, T. C.; Voitsekhovitch, I. A.; Roach, C. M.; Walsh, M. J. [Culham Science Centre, EURATOM/CCFE Fusion Association (United Kingdom)

    2010-08-15T23:59:59.000Z

    The linear and nonlinear versions of the Canonical Profiles Transport Model (CPTM), which includes both heat and particle transport equations, are used to simulate core and pedestal plasma for JET, and MAST H-mode shots. Simulations by the nonlinear version show reasonable agreement with experiment for both ELMy and ELM-free shots. RMS deviations of calculated results from the experimental ones are on the level 10-12% in main. The calculated ion and electron temperature profiles are very insensitive to the change of the deposited peaked power profiles. The calculated pedestal temperature rapidly increases with plasma current; density profile peaking increases at low collisionalities.

  17. GREET 1.0 -- Transportation fuel cycles model: Methodology and use

    SciTech Connect (OSTI)

    Wang, M.Q.

    1996-06-01T23:59:59.000Z

    This report documents the development and use of the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. The model, developed in a spreadsheet format, estimates the full fuel-cycle emissions and energy use associated with various transportation fuels for light-duty vehicles. The model calculates fuel-cycle emissions of five criteria pollutants (volatile organic compounds, Co, NOx, SOx, and particulate matter measuring 10 microns or less) and three greenhouse gases (carbon dioxide, methane, and nitrous oxide). The model also calculates the total fuel-cycle energy consumption, fossil fuel consumption, and petroleum consumption using various transportation fuels. The GREET model includes 17 fuel cycles: petroleum to conventional gasoline, reformulated gasoline, clean diesel, liquefied petroleum gas, and electricity via residual oil; natural gas to compressed natural gas, liquefied petroleum gas, methanol, hydrogen, and electricity; coal to electricity; uranium to electricity; renewable energy (hydropower, solar energy, and wind) to electricity; corn, woody biomass, and herbaceous biomass to ethanol; and landfill gases to methanol. This report presents fuel-cycle energy use and emissions for a 2000 model-year car powered by each of the fuels that are produced from the primary energy sources considered in the study.

  18. A scaleable architecture for the modeling and simulation of intelligent transportation systems.

    SciTech Connect (OSTI)

    Ewing, T.; Tentner, A.

    1999-03-17T23:59:59.000Z

    A distributed, scaleable architecture for the modeling and simulation of Intelligent Transportation Systems on a network of workstations or a parallel computer has been developed at Argonne National Laboratory. The resulting capability provides a modular framework supporting plug-in models, hardware, and live data sources; visually realistic graphics displays to support training and human factors studies; and a set of basic ITS models. The models and capabilities are described, along with atypical scenario involving dynamic rerouting of smart vehicles which send probe reports to and receive traffic advisories from a traffic management center capable of incident detection.

  19. Uncertainty Analysis Framework - Hanford Site-Wide Groundwater Flow and Transport Model

    SciTech Connect (OSTI)

    Cole, Charles R.; Bergeron, Marcel P.; Murray, Christopher J.; Thorne, Paul D.; Wurstner, Signe K.; Rogers, Phillip M.

    2001-11-09T23:59:59.000Z

    Pacific Northwest National Laboratory (PNNL) embarked on a new initiative to strengthen the technical defensibility of the predictions being made with a site-wide groundwater flow and transport model at the U.S. Department of Energy Hanford Site in southeastern Washington State. In FY 2000, the focus of the initiative was on the characterization of major uncertainties in the current conceptual model that would affect model predictions. The long-term goals of the initiative are the development and implementation of an uncertainty estimation methodology in future assessments and analyses using the site-wide model. This report focuses on the development and implementation of an uncertainty analysis framework.

  20. Influence of Mg2+ on CaCO3 precipitation during subsurface reactive...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    subsurface reactive transport in a homogeneous silicon-etched pore network. Abstract: Calcium carbonate (CaCO3) geochemical reactions exert a fundamental control on the...

  1. Rattling and freezing in a 1-D transport model

    E-Print Network [OSTI]

    Jean-Pierre Eckmann; Lai-Sang Young

    2010-07-04T23:59:59.000Z

    We consider a heat conduction model introduced in \\cite{Collet-Eckmann 2009}. This is an open system in which particles exchange momentum with a row of (fixed) scatterers. We assume simplified bath conditions throughout, and give a qualitative description of the dynamics extrapolating from the case of a single particle for which we have a fairly clear understanding. The main phenomenon discussed is {\\it freezing}, or the slowing down of particles with time. As particle number is conserved, this means fewer collisions per unit time, and less contact with the baths; in other words, the conductor becomes less effective. Careful numerical documentation of freezing is provided, and a theoretical explanation is proposed. Freezing being an extremely slow process, however, the system behaves as though it is in a steady state for long durations. Quantities such as energy and fluxes are studied, and are found to have curious relationships with particle density.

  2. Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines

    E-Print Network [OSTI]

    Cho, Yeunwoo, 1973-

    2004-01-01T23:59:59.000Z

    A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption that the multi-grade oil can be modeled as a compound of several ...

  3. Multispecies Reactive Tracer Test in a Sand and

    E-Print Network [OSTI]

    Multispecies Reactive Tracer Test in a Sand and Gravel Aquifer, Cape Cod, Massachusetts United;Multispecies Reactive Tracer Test in a Sand and Gravel Aquifer, Cape Cod, Massachusetts Part 2 Transport- effectiveness for prevention and control of pollution to air, land, water, and subsurface resources; protection

  4. Modeling and Diagnostics of Fuel Cell Porous Media for Improving Water Transport

    SciTech Connect (OSTI)

    Allen, Jeff; M'edici, Ezequiel

    2011-07-01T23:59:59.000Z

    When a fuel cell is operating at high current density, water accumulation is a significant cause of performance and component degradation. Investigating the water transport inside the fuel cell is a challenging task due to opacity of the components, the randomness of the porous materials, and the difficulty in gain access to the interior for measurement due to the small dimensions of components. Numerical simulation can provide a good insight of the evolution of the water transport under different working condition. However, the validation of those simulations is remains an issue due the same experimental obstacles associated with in-situ measurements. The discussion herein will focus on pore-network modeling of the water transport on the PTL and the insights gained from simulations as well as in the validation technique. The implications of a recently published criterion to characterize PTL, based on percolation theory, and validate numerical simulation are discussed.

  5. Assimilation of satellite images into a sediment transport model of Lake Michigan.

    SciTech Connect (OSTI)

    Stroud, J.; Lesht, B.; Beletsky, D.; Stein, M.; Univ. of Pennsylvania; NOAA; Univ. of Michigan; Univ. of Chicago

    2009-01-01T23:59:59.000Z

    In this paper we develop and examine several schemes for combining daily images obtained from the Sea-viewing Wide Field Spectrometer (SeaWiFS) with a two-dimensional sediment transport model of Lake Michigan. We consider two data assimilation methods, direct insertion and a kriging-based approach, and perform a forecasting study focused on a 2-month period in spring 1998 when a large storm caused substantial amounts of sediment resuspension and horizontal sediment transport in the lake. By beginning with the simplest possible forecast method and sequentially adding complexity we are able to assess the improvements offered by combining the satellite data with the numerical model. In our application, we find that data assimilation schemes that include both the data and the lake dynamics improve forecast root mean square error by 40% over purely model-based approaches and by 20% over purely data-based approaches.

  6. Local models of stellar convection: Reynolds stresses and turbulent heat transport

    E-Print Network [OSTI]

    P. J. Käpylä; M. J. Korpi; I. Tuominen

    2004-09-06T23:59:59.000Z

    We study stellar convection using a local three-dimensional MHD model, with which we investigate the influence of rotation and large-scale magnetic fields on the turbulent momentum and heat transport. The former is studied by computing the Reynolds stresses, the latter by calculating the correlation of velocity and temperature fluctuations, both as functions of rotation and latitude. We find that the horisontal correlation, Q_(theta phi), capable of generating horisontal differential rotation, is mostly negative in the southern hemisphere for Coriolis numbers exceeding unity, corresponding to equatorward flux of angular momentum in accordance with solar observations. The radial component Q_(r phi) is negative for slow and intermediate rotation indicating inward transport of angular momentum, while for rapid rotation, the transport occurs outwards. Parametrisation in terms of the mean-field Lambda-effect shows qualitative agreement with the turbulence model of Kichatinov & R\\"udiger (1993) for the horisontal part H \\propto Q_(theta phi)/cos(theta), whereas for the vertical part, V \\propto Q_(r phi)/sin(theta), agreement only for intermediate rotation exists. The Lambda-coefficients become suppressed in the limit of rapid rotation, this rotational quenching being stronger for the V component than for H. We find that the stresses are enhanced by the presence of the magnetic field for field strengths up to and above the equipartition value, without significant quenching. Concerning the turbulent heat transport, our calculations show that the transport in the radial direction is most efficient at the equatorial regions, obtains a minimum at midlatitudes, and shows a slight increase towards the poles. The latitudinal heat transport does not show a systematic trend as function of latitude or rotation.

  7. Analytical model of electron transport in polycrystalline, degenerately doped ZnO films

    SciTech Connect (OSTI)

    Bikowski, André, E-mail: andre.bikowski@helmholtz-berlin.de; Ellmer, Klaus [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

    2014-10-14T23:59:59.000Z

    An analytical description of the charge carrier transport, valid for non-degenerated and degenerated semiconductors, was developed, critically reviewed, and fitted to the temperature-dependent Hall mobility data of magnetron sputtered, degenerately doped ZnO:Al films. Our extended model for grain boundary scattering in semiconductors of arbitrary degeneracy is based on previous models from literature and suitable to describe the Hall mobility of the carriers as a function of the free carrier concentration and the temperature at the same time. It is mathematically simple enough for a fast fit procedure, which is not possible with most of the previous models. Applying a combined transport model consisting of ionized impurity scattering, phonon scattering, and grain boundary scattering in degenerate semiconductors, we were able to determine the trap density at the grain boundaries N{sub t} ? 3?×?10{sup 13} to 5?×?10{sup 13?}cm{sup ?2} and the deformation potential E{sub ac} in the range of 5?eV to 9?eV depending on the details of the transport model.

  8. FINAL REPORT:Observation and Simulations of Transport of Molecules and Ions Across Model Membranes

    SciTech Connect (OSTI)

    MURAD, SOHAIL [University of Illinois at Chicago] [University of Illinois at Chicago; JAMESON, CYNTHIA J [University of Illinois at Chicago] [University of Illinois at Chicago

    2013-10-22T23:59:59.000Z

    During the this new grant we developed a robust methodology for investigating a wide range of properties of phospho-lipid bilayers. The approach developed is unique because despite using periodic boundary conditions, we can simulate an entire experiment or process in detail. For example, we can follow the entire permeation process in a lipid-membrane. This includes transport from the bulk aqueous phase to the lipid surface; permeation into the lipid; transport inside the lipid; and transport out of the lipid to the bulk aqueous phase again. We studied the transport of small gases in both the lipid itself and in model protein channels. In addition, we have examined the transport of nanocrystals through the lipid membrane, with the main goal of understanding the mechanical behavior of lipids under stress including water and ion leakage and lipid flip flop. Finally we have also examined in detail the deformation of lipids when under the influence of external fields, both mechanical and electrostatic (currently in progress). The important observations and conclusions from our studies are described in the main text of the report

  9. Elements of fractal generalization of dual-porosity model for solute transport in unsaturated fractured rocks

    SciTech Connect (OSTI)

    Bolshov, L.; Kondratenko, P.; Matveev, L.; Pruess, K.

    2008-09-01T23:59:59.000Z

    In this study, new elements were developed to generalize the dual-porosity model for moisture infiltration on and solute transport in unsaturated rocks, taking into account fractal aspects of the percolation process. Random advection was considered as a basic mechanism of solute transport in self-similar fracture systems. In addition to spatial variations in the infiltration velocity field, temporal fluctuations were also taken into account. The rock matrix, a low-permeability component of the heterogeneous geologic medium, acts as a trap for solute particles and moisture. Scaling relations were derived for the moisture infiltration flux, the velocity correlation length, the average velocity of infiltration, and the velocity correlation function. The effect of temporal variations in precipitation intensity on the infiltration processes was analyzed. It showed that the mode of solute transport is determined by the power exponent in the advection velocity correlation function and the dimensionality of the trapping system, both of which may change with time. Therefore, depending on time, various transport regimes may be realized: superdiffusion, subdiffusion, or classical diffusion. The complex structure of breakthrough curves from changes in the transport regimes was also examined. A renormalization of the solute source strength due to characteristic fluctuations of highly disordered media was established.

  10. Modeling the Effect of Sedimentation on Cesium Transport in Fourmile Branch

    SciTech Connect (OSTI)

    Chen, K.F.

    2001-02-22T23:59:59.000Z

    The major mechanisms of radioactive material transport and fate in surface water are (1) sources, (2) dilution, advection and dispersion of radionuclides by flow and surface waves, (3) radionuclide decay, and (4) interaction between sediment and radionuclides. STREAM II, an aqueous transport module of the Savannah River Site emergency response WIND system, accounts for the source term, and the effects of dilution, advection and dispersion. Although the model has the capability to account for nuclear decay, due to the short time interval of interest for emergency response, the effect of nuclear decay is very small and so it is not employed. The interactions between the sediment and radionuclides are controlled by the flow conditions and physical and chemical characteristics of the radionuclides and the sediment constituents. The STREAM II version used in emergency response does not model the effects of sediment deposition/resuspension to minimize computing time. This study estimates the effects of sediment deposition/resuspension on radionuclide aqueous transport. For radionuclides that adsorb onto suspended sediment, the omission of deposition/resuspension effects overestimates the downstream radionuclide peak concentration and is therefore conservative. For the case of cesium transport in the Fourmile Branch, the calculated reduction in peak concentration as the cesium is transported downstream is greater with sediment deposition modeled than without. For example, including the effects of sediment deposition/resuspension in the STREAM II calculation results in a 72 percent reduction in the downstream (5075 meters downstream from H-Area) peak cesium concentration. It is important to note that the high partition coefficient appropriate for cesium enhances the importance of sediment deposition/resuspension; the reduction in the calculated peak concentration would be less for radioisotopes with lower partition coefficients.

  11. Computing observables in curved multifield models of inflation - A guide (with code) to the transport method

    E-Print Network [OSTI]

    Mafalda Dias; Jonathan Frazer; David Seery

    2015-02-10T23:59:59.000Z

    We describe how to apply the transport method to compute inflationary observables in a broad range of multiple-field models. The method is efficient and encompasses scenarios with curved field-space metrics, violations of slow-roll conditions and turns of the trajectory in field space. It can be used for an arbitrary mass spectrum, including massive modes and models with quasi-single-field dynamics. In this note we focus on practical issues. It is accompanied by a Mathematica code which can be used to explore suitable models, or as a basis for further development.

  12. Computing observables in curved multifield models of inflation - A guide (with code) to the transport method

    E-Print Network [OSTI]

    Dias, Mafalda; Seery, David

    2015-01-01T23:59:59.000Z

    We describe how to apply the transport method to compute inflationary observables in a broad range of multiple-field models. The method is efficient and encompasses scenarios with curved field-space metrics, violations of slow-roll conditions and turns of the trajectory in field space. It can be used for an arbitrary mass spectrum, including massive modes and models with quasi-single-field dynamics. In this note we focus on practical issues. It is accompanied by a Mathematica code which can be used to explore suitable models, or as a basis for further development.

  13. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    characteristic of stable isotope enrichment. The values of !isotope ratios of sulfur in these sulfate samples demonstrated a clear enrichmentisotope ( 34 S) (Canfield, 2001). The characteristic enrichment

  14. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    and detachment of calcium and carbonate ions. Crystalactivity product of calcium and carbonate in solution, K spJ. 2012. Upscaling calcium carbonate precipitation rates

  15. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    34 S fractionation . Summary A mesoscale study of isotopicion exchange and ! 44 Ca . A mesoscale study of isotopicmodeling and ! 34 S . A mesoscale study of isotopic

  16. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    W.T. (eds. ), 1999. Bioremediation of Contaminated Soils.heterogeneity and bioremediation induced biogeochemicalK.S. 2007. In Situ Bioremediation. Advances in Applied

  17. Stable Isotope Fractionations in Biogeochemical Reactive Transport

    E-Print Network [OSTI]

    Druhan, Jennifer Lea

    2012-01-01T23:59:59.000Z

    Work Plan for the UMTRA Project Old Rifle Site, GJO-99-88-influent values and the UMTRA compliance limit for uraniumTailings Remediation Action (UMTRA) project, which included

  18. TransCom model simulations of CH? and related species: linking transport, surface flux and chemical loss with CH? variability in the troposphere and lower stratosphere

    E-Print Network [OSTI]

    Patra, P. K.

    A chemistry-transport model (CTM) intercomparison experiment (TransCom-CH?) has been designed to investigate the roles of surface emissions, transport and chemical loss in simulating the global methane distribution. Model ...

  19. Evaluation of Transport and Dispersion Models: A Controlled Comparison of HPAC and NARAC Predictions

    SciTech Connect (OSTI)

    Warner, S; Heagy, J F; Platt, N; Larson, D; Sugiyama, G; Nasstrom, J S; Foster, K T; Bradley, S; Bieberbach, G

    2001-05-01T23:59:59.000Z

    During fiscal year 2000, a series of studies in support of the Defense Threat Reduction Agency (DTRA) was begun. The goal of these studies is to improve the verification, validation, and accreditation (VV&A) of hazard prediction and assessment models and capabilities. These studies are part of a larger joint VV&A collaborative effort that DTRA and the Department of Energy (DOE), via the Lawrence Livermore National Laboratory (LLNL), are conducting. This joint effort includes comparisons of the LLNL and DTRA transport and dispersion (T&D) modeling systems, NARAC and HPAC, respectively. The purpose of this work is to compare, in a systematic way, HPAC and NARAC model predictions for a set of controlled hypothetical release scenarios. Only ''model-versus-model'' comparisons are addressed in this work. Model-to-field trial comparisons for HPAC and NARAC have been addressed in a recent companion study, in support of the same joint VV&A effort.

  20. Introduction Transport in disordered graphene

    E-Print Network [OSTI]

    Fominov, Yakov

    Introduction Transport in disordered graphene Summary Ballistic transport in disordered graphene P, Gornyi, Mirlin Ballistic transport in disordered graphene #12;Introduction Transport in disordered graphene Summary Outline 1 Introduction Model Experimental motivation Transport in clean graphene 2

  1. Performance of a zerovalent iron reactive barrier for the treatment of arsenic in groundwater: Part 2. Geochemical modeling and solid phase studies

    SciTech Connect (OSTI)

    Beak, Douglas G.; Wilkin, Richard T.; (EPA)

    2009-06-12T23:59:59.000Z

    Arsenic uptake processes were evaluated in a zerovalent iron reactive barrier installed at a lead smelting facility using geochemical modeling, solid-phase analysis, and X-ray absorption spectroscopy techniques. Aqueous speciation of arsenic is expected to play a key role in directing arsenic uptake processes. Geochemical modeling reveals contrasting pH-dependencies for As(III) and As(V) precipitation. At the moderately alkaline pH conditions typically encountered in zerovalent iron reactive barriers, As(III) is unlikely to precipitate as an oxide or a sulfide phase. Conversely, increasing pH is expected to drive precipitation of metal arsenates including ferrous arsenate. Bacterially mediated sulfate reduction plays an important role in field installations of granular iron. Neoformed iron sulfides provide surfaces for adsorption of oxyanion and thioarsenic species of As(III) and As(V) and are expected to provide enhanced arsenic removal capacity. X-ray absorption near edge structure (XANES) spectra indicate that arsenic is sequestered in the solid phase as both As(III) and As(V) in coordination environments with O and S. Arsenic removal in the PRB probably results from several pathways, including adsorption to iron oxide and iron sulfide surfaces, and possible precipitation of ferrous arsenate. Corrosion of granular iron appears to result in some As(III) oxidation to As(V) as the proportion of As(V) to As(III) in the solid phase is greater compared to influent groundwater. As(0) was not detected in the PRB materials. These results are broadly comparable to laboratory based studies of arsenic removal by zerovalent iron, but additional complexity is revealed in the field environment, which is largely due to the influence of subsurface microbiota.

  2. MSIV leakage airborne iodine transport

    SciTech Connect (OSTI)

    Cline, J.E. (Cline Associates Inc., Rockville, MD (United States))

    1993-01-01T23:59:59.000Z

    Gaseous iodine deposits on surfaces exposed to vapors. Basic chemical and physical principles predict this behavior, and several laboratory and in-plant measurements demonstrate the characteristic. An empirical model was developed that describes the deposition, resuspension, and transformation of airborne radioiodine molecular species as a stream containing these forms moves along its pathway. The model uses a data base of measured values of deposition and resuspension rates in its application and describes the conversion of the more reactive inorganic iodine species I[sub 2] to the less reactive organic species CH[sub 3]I as the iodine deposits and resuspends along the path. It also considers radioactive decay and chemical surface bonding during residence on surfaces. For the 8-day [sup 131]I, decay during the airborne portion of the transport is negligible. Verification of the model included measurement tests of long gaseous-activity sampling lines of different diameters, operated at different flow rates and stream temperatures. The model was applied to the streams at a boiling water reactor nuclear power plant to describe the transport through leaking main steam isolation valves (MSIVs), following a loss-of-coolant accident.

  3. Simplified 1-D Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects

    E-Print Network [OSTI]

    Fleenor, William E.; Bombardelli, Fabian

    2013-01-01T23:59:59.000Z

    Hydrodynamic and Salinity Transport Modeling of the Sacramento–San Joaquin Delta: Sea Level Rise and Water Diversion Effects

  4. Triangular flow in heavy ion collisions in a multiphase transport model 

    E-Print Network [OSTI]

    Xu, Jun; Ko, Che Ming.

    2011-01-01T23:59:59.000Z

    (RHIC) have provided important information on the properties of produced quark-gluon plasma (QGP) [1?4]. In particular, the large elliptic flow observed in experiments has led to the conclusion that the produced quark-gluon plasma is strongly...,10]. With the large parton scattering cross section, the transport model is also able to describe the hexadecupole flow measured at RHIC [11]. More recently, the importance of the triangular flow, which originates from fluctuations in the initial collision...

  5. Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions 

    E-Print Network [OSTI]

    Zhang, Liqing

    2011-07-01T23:59:59.000Z

    Peters August 2011 Major Subject: Industrial Engineering iii ABSTRACT Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions. (August 2011) Liqing Zhang, B.S.; M.S., Tsinghua University, P.R. China Chair... An Illustration of (Q,~s, ~S) Policy ( m = ? s1n?Qn C ? + 1 ) . . . . . . . . 52 5 Optimal Policies for Special Case . . . . . . . . . . . . . . . . . . . . 71 6 Influence of Parameter K . . . . . . . . . . . . . . . . . . . . . . . . 74 7 Influence...

  6. Groundwater transport modeling of constituents originating from the Burial Grounds Complex

    SciTech Connect (OSTI)

    Andersen, P.F.; Shupe, M.G.; Spalding, C.P. [GeoTrans, Inc., Sterling, VA (US)

    1992-10-30T23:59:59.000Z

    The Savannah River Site (SRS), operates a number of sites for the land disposal of various leachable radionuclide, organic, and inorganic wastes. Located within the General Separations Area (GSA) of SRS are the Low Level Radioactive Waste Disposal Facility (LLRWDF) and the Old Burial Ground (OBG). A portion of the LLRWDF has been designated as the Mixed Waste Management Facility (MWMF). The OBG began receiving waste in 1952 and was closed in 1974. Various wastes, including transuranic, intermediate and low level beta-gamma, and solvents, were received during this period of operation. In 1969, prior to the closing of the OBG, a portion of the MWMF/LLRWDF (the MWMF) began receiving waste. GeoTrans, Inc. was contracted by WSRC to conduct a numerical modeling study to assess groundwater flow and contaminant transport in the vicinity of the MWMF in support of an Alternate Concentration Limits demonstration for the Part B permit. The project was divided into two phases: development of a groundwater flow model of the hydrogeologic system underlying the MWMF which includes the entire GSA, and development of a solute transport model to assess migration of 19 designated constituents of concern (COCs) over a period 30 years into the future. The first phase was completed in May of 1992 and the results documented in GeoTrans (1992). That report serves as the companion volume to the present contaminant transport modeling report. The transport study is intended to develop predictions of concentration and mass flux of the 19 COCs at downgradient exposure points over the 30 year period of interest. These results are to be used in human health and ecological risk assessments which are also being performed in support of the Part B permit.

  7. A multi-model assessment of pollution transport to the Arctic

    SciTech Connect (OSTI)

    Shindell, D T; Chin, M; Dentener, F; Doherty, R M; Faluvegi, G; Fiore, A M; Hess, P; Koch, D M; MacKenzie, I A; Sanderson, M G; Schultz, M G; Schulz, M; Stevenson, D S; Teich, H; Textor, C; Wild, O; Bergmann, D J; Bey, I; Bian, H; Cuvelier, C; Duncan, B N; Folberth, G; Horowitz, L W; Jonson, J; Kaminski, J W; Marmer, E; Park, R; Pringle, K J; Schroeder, S; Szopa, S; Takemura, T; Zeng, G; Keating, T J; Zuber, A

    2008-03-13T23:59:59.000Z

    We examine the response of Arctic gas and aerosol concentrations to perturbations in pollutant emissions from Europe, East and South Asia, and North America using results from a coordinated model intercomparison. These sensitivities to regional emissions (mixing ratio change per unit emission) vary widely across models and species. Intermodel differences are systematic, however, so that the relative importance of different regions is robust. North America contributes the most to Arctic ozone pollution. For aerosols and CO, European emissions dominate at the Arctic surface but East Asian emissions become progressively more important with altitude, and are dominant in the upper troposphere. Sensitivities show strong seasonality: surface sensitivities typically maximize during boreal winter for European and during spring for East Asian and North American emissions. Mid-tropospheric sensitivities, however, nearly always maximize during spring or summer for all regions. Deposition of black carbon (BC) onto Greenland is most sensitive to North American emissions. North America and Europe each contribute {approx}40% of total BC deposition to Greenland, with {approx}20% from East Asia. Elsewhere in the Arctic, both sensitivity and total BC deposition are dominated by European emissions. Model diversity for aerosols is especially large, resulting primarily from differences in aerosol physical and chemical processing (including removal). Comparison of modeled aerosol concentrations with observations indicates problems in the models, and perhaps, interpretation of the measurements. For gas phase pollutants such as CO and O{sub 3}, which are relatively well-simulated, the processes contributing most to uncertainties depend on the source region and altitude examined. Uncertainties in the Arctic surface CO response to emissions perturbations are dominated by emissions for East Asian sources, while uncertainties in transport, emissions, and oxidation are comparable for European and North American sources. At higher levels, model-to-model variations in transport and oxidation are most important. Differences in photochemistry appear to play the largest role in the intermodel variations in Arctic ozone sensitivity, though transport also contributes substantially in the mid-troposphere.

  8. A model for thermally driven heat and air transport in passive solar buildings

    SciTech Connect (OSTI)

    Jones, G.F.; Balcomb, J.D.; Otis, D.R.

    1985-01-01T23:59:59.000Z

    A model for transient interzone heat and air flow transport in passive solar buildings is presented incorporating wall boundary layers in stratified zones, and with interzone transport via apertures (doors and windows). The model includes features that have been observed in measurements taken in more than a dozen passive solar buildings. The model includes integral formulations of the laminar and turbulent boundary layer equations for the vertical walls which are then coupled to a one-dimensional core model for each zone. The cores in each zone exchange mass and energy through apertures that are modeled by an orifice type equation. The procedure is transient in that time dependence is retained only in the core equations which are solved by an explicit method. The model predicts room stratification of about 2/sup 0/C/m (1.1/sup 0/F/ft) for a room-to-room temperature difference of 0.56/sup 0/C(1/sup 0/F) which is in general agreement with the data.

  9. Model for thermally driven heat and air transport in passive solar buildings

    SciTech Connect (OSTI)

    Jones, G.F.; Balcomb, J.D.; Otis, D.R.

    1985-01-01T23:59:59.000Z

    A model for transient interzone heat and air flow transport in passive solar buildings is presented incorporating wall boundary layers in stratified zones, and with interzone transport via apertures (doors and windows). The model includes features that have been observed in measurements taken in more than a dozen passive solar buildings. The model includes integral formulations of the laminar and turbulent boundary layer equations for the vertical walls which are then coupled to a one-dimensional core model for each zone. The cores in each zone exchange mass and energy through apertures that are modeled by an orifice type equation. The procedure is transient in that time dependence is retained only in the core equations which are solved by an explicit method. The model predicts room stratification of about 2/sup 0/C/m (1.1/sup 0/F/ft) for a room-to-room temperature difference of 0.56/sup 0/C(1/sup 0/F) which is in general agreement with the data. 38 references, 10 figures, 1 table.

  10. Area-preserving maps models of gyro-averaged ${\\bf E} \\times {\\bf B}$ chaotic transport

    E-Print Network [OSTI]

    J. D. da Fonseca; D. del-Castillo-Negrete; I. L. Caldas

    2014-09-10T23:59:59.000Z

    Discrete maps have been extensively used to model 2-dimensional chaotic transport in plasmas and fluids. Here we focus on area-preserving maps describing finite Larmor radius (FLR) effects on ${\\bf E} \\times {\\bf B}$ chaotic transport in magnetized plasmas with zonal flows perturbed by electrostatic drift waves. FLR effects are included by gyro-averaging the Hamiltonians of the maps which, depending on the zonal flow profile, can have monotonic or non-monotonic frequencies. In the limit of zero Larmor radius, the monotonic frequency map reduces to the standard Chirikov-Taylor map, and, in the case of non-monotonic frequency, the map reduces to the standard nontwist map. We show that in both cases FLR leads to chaos suppression, changes in the stability of fixed points, and robustness of transport barriers. FLR effects are also responsible for changes in the phase space topology and zonal flow bifurcations. Dynamical systems methods based on recurrence time statistics are used to quantify the dependence on the Larmor radius of the threshold for the destruction of transport barriers.

  11. A critical view on transport and entanglement in models of photosynthesis

    E-Print Network [OSTI]

    Markus Tiersch; Sandu Popescu; Hans J. Briegel

    2012-08-23T23:59:59.000Z

    We revisit critically the recent claims, inspired by quantum optics and quantum information, that there is entanglement in the biological pigment protein complexes, and that it is responsible for the high transport efficiency. While unexpectedly long coherence times were experimentally demonstrated, the existence of entanglement is, at the moment, a purely theoretical conjecture; it is this conjecture that we analyze. As demonstrated by a toy model, a similar transport phenomenology can be obtained without generating entanglement. Furthermore, we also argue that even if entanglement does exist, it is purely incidental and seems to plays no essential role for the transport efficiency. We emphasize that our paper is not a proof that entanglement does not exist in light-harvesting complexes - this would require a knowledge of the system and its parameters well beyond the state of the art. Rather, we present a counter-example to the recent claims of entanglement, showing that the arguments, as they stand at the moment, are not sufficiently justified and hence cannot be taken as proof for the existence of entanglement, let alone of its essential role, in the excitation transport.

  12. Predicting Fate and Transport of Contaminants in the Vadose Zone using a Soil Screening Model

    SciTech Connect (OSTI)

    Rucker, G.

    2002-08-14T23:59:59.000Z

    Soil Screening Levels (SSLs) are threshold concentrations below which there is no concern for the migration of residual soil contaminants to the aquifer above maximum contaminant levels (MCLs). At sites where contaminant concentrations exceed SSLs, further study maybe warranted under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). SSLs are based upon simplified fate and transport assumptions, but the guidance allows the flexibility to develop a detailed modeling approach that accounts for complex site variables such as degradation and thickness of the vadose zone. The distinct advantage of the detailed modeling is that individual sites may calculate a less restrictive, but still protective SSL. A Multi-Layer Vadose Zone Contaminant Migration Model [VZCOMML(C)] was developed at the Savannah River Site to allay the higher costs of detailed modeling and achieve a higher clean-up level. The software model is faster, simpler, and less expensive to us e than other commercially available codes.

  13. Using a scalable modeling and simulation framework to evaluate the benefits of intelligent transportation systems.

    SciTech Connect (OSTI)

    Ewing, T.; Tentner, A.

    2000-03-21T23:59:59.000Z

    A scalable, distributed modeling and simulation framework has been developed at Argonne National Laboratory to study Intelligent Transportation Systems. The framework can run on a single-processor workstation, or run distributed on a multiprocessor computer or network of workstations. The framework is modular and supports plug-in models, hardware, and live data sources. The initial set of models currently includes road network and traffic flow, probe and smart vehicles, traffic management centers, communications between vehicles and centers, in-vehicle navigation systems, roadway traffic advisories. The modeling and simulation capability has been used to examine proposed ITS concepts. Results are presented from modeling scenarios from the Advanced Driver and Vehicle Advisory Navigation Concept (ADVANCE) experimental program to demonstrate how the framework can be used to evaluate the benefits of ITS and to plan future ITS operational tests and deployment initiatives.

  14. GEOCENTRIFUGE STUDIES OF FLOW AND TRANSPORT IN POROUS MEDIA, FINAL REPORT FOR GRANT NUMBER DE-FG02-03ER63567 TO THE UNIVERSITY OF IDAHO (RW SMITH), ENVIRONMENTAL MANAGEMENT SCIENCE PROGRAM PROJECT NUMBER 86598, COUPLED FLOW AND REACTIVITY IN VARIABLY SATURATED POROUS MEDIA

    SciTech Connect (OSTI)

    Robert W. Smith; Carl D. Palmer; Earl D. Mattson

    2007-06-15T23:59:59.000Z

    Improved models of contaminant migration in heterogeneous, variably saturated porous media are required to better define the long-term stewardship requirements for U.S. Department of Energy (DOE) lands and to assist in the design of effective vadose-zone barriers to contaminant migrations. The development of these improved models requires field and laboratory results to evaluate their efficacy. However, controlled laboratory experiments simulating vadose conditions can require extensive period of time, and often are conducted at condition near saturation rather than the much drier conditions common in many contaminated arid vadose zone sites. Collaborative research undertaken by the Idaho National Laboratory (INL) and the University of Idaho as part of this Environmental Management Science Program project focused on the development and evaluation of geocentrifuge techniques and equipment that allows vadose zone experiments to be conducted for relevant conditions in time frames not possible in conventional bench top experiments. A key and novel aspect of the research was the use of the 2-meter radius geocentrifuge capabilities at the Idaho National Laboratory to conduct unsaturated transport experiments. Specifically, the following activities were conducted ** Reviewing of the theory of unsaturated flow in the geocentrifuge to establish the range of centrifuge accelerations/experimental conditions and the translation of centrifuge results to 1 gravity applications. ** Designing, constructing, and testing of in-flight experimental apparatus allowing the replication of traditional bench top unsaturated transport experiments on the geocentrifuge. ** Performing unsaturated 1-dimenstional column geocentrifuge experiments using conservative tracers to evaluate the effects of increased centrifugal acceleration on derived transport properties and assessing the scaling relationships for these properties. Because the application of geocentrifuge techniques to vadose transport is in its infancy experimental apparatus such as pumps, flow meters, columns, fraction collectors, etc. that would reliably function under the increased self weight experienced on the centrifuge had to be developed and tested as part of this project. Although, we initially planed to conduct experiments using reactive tracer and 2-dimensional heterogeneities, the cost and time associated with designing, building, and testing of experimental apparatus limited our experimental program to conservative tracer experiments using 1-dimensional columns. The results we obtained in this study indicate that the geocentrifuge technique is a viable experimental method for the study of subsurface processes where gravitational acceleration is important. The geocentrifuge allows experiments to be completed more quickly than tests conducted at 1-g, can be used to experimentally address important scaling issues, and permits experiments under a range of conditions that would be difficult or impossible using conventional approaches. The application of the geocentrifuge approaches and associated models developed in this project allows more meaningful investigation of DOE relevant vadose-zone issues under scalable conditions in time frames previously not obtainable.

  15. Modeling benzene plume elongation mechanisms exerted by ethanol using RT3D with a general

    E-Print Network [OSTI]

    Alvarez, Pedro J.

    Modeling benzene plume elongation mechanisms exerted by ethanol using RT3D with a general substrate ethanol on benzene fate and transport in fuel-contaminated groundwater and to discern the most influential benzene plume elongation mechanisms. The model, developed as a module for the Reactive Transport in 3

  16. Triangular flow in heavy ion collisions in a multiphase transport model

    E-Print Network [OSTI]

    Jun Xu; Che Ming Ko

    2011-06-28T23:59:59.000Z

    We have obtained a new set of parameters in a multiphase transport (AMPT) model that are able to describe both the charged particle multiplicity density and elliptic flow measured in Au+Au collisions at center of mass energy $\\sqrt{s_{NN}}=200$ GeV at the Relativistic Heavy Ion Collider (RHIC), although they still give somewhat softer transverse momentum spectra. We then use the model to predict the triangular flow due to fluctuations in the initial collision geometry and study its effect relative to those from other harmonic components of anisotropic flows on the di-hadron azimuthal correlations in both central and mid-central collisions.

  17. Development and applications of GREET 2.7 -- The Transportation Vehicle-CycleModel.

    SciTech Connect (OSTI)

    Burnham, A.; Wang, M. Q.; Wu, Y.

    2006-12-20T23:59:59.000Z

    Argonne National Laboratory has developed a vehicle-cycle module for the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model. The fuel-cycle GREET model has been cited extensively and contains data on fuel cycles and vehicle operations. The vehicle-cycle model evaluates the energy and emission effects associated with vehicle material recovery and production, vehicle component fabrication, vehicle assembly, and vehicle disposal/recycling. With the addition of the vehicle-cycle module, the GREET model now provides a comprehensive, lifecycle-based approach to compare the energy use and emissions of conventional and advanced vehicle technologies (e.g., hybrid electric vehicles and fuel cell vehicles). This report details the development and application of the GREET 2.7 model. The current model includes six vehicles--a conventional material and a lightweight material version of a mid-size passenger car with the following powertrain systems: internal combustion engine, internal combustion engine with hybrid configuration, and fuel cell with hybrid configuration. The model calculates the energy use and emissions that are required for vehicle component production; battery production; fluid production and use; and vehicle assembly, disposal, and recycling. This report also presents vehicle-cycle modeling results. In order to put these results in a broad perspective, the fuel-cycle model (GREET 1.7) was used in conjunction with the vehicle-cycle model (GREET 2.7) to estimate total energy-cycle results.

  18. Prediction of continental shelf sediment transport using a theoretical model of the wave-current boundary layer

    E-Print Network [OSTI]

    Goud, Margaret R

    1987-01-01T23:59:59.000Z

    This thesis presents an application of the Grant-Madsen-Glenn bottom boundary layer model (Grant and Madsen, 1979; Glenn and Grant, 1987) to predictions of sediment transport on the continental shelf. The analysis is a ...

  19. Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake

    E-Print Network [OSTI]

    Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 sediment resuspension of mixed (cohesive plus noncohesive) sediment is developed and applied to quantitatively simulate the March 1998 resuspension events in southern Lake Michigan. Some characteristics

  20. Modeling the Energy Use of a Connected and Automated Transportation System (Poster)

    SciTech Connect (OSTI)

    Gonder, J.; Brown, A.

    2014-07-01T23:59:59.000Z

    Early research points to large potential impacts of connected and automated vehicles (CAVs) on transportation energy use - dramatic savings, increased use, or anything in between. Due to a lack of suitable data and integrated modeling tools to explore these complex future systems, analyses to date have relied on simple combinations of isolated effects. This poster proposes a framework for modeling the potential energy implications from increasing penetration of CAV technologies and for assessing technology and policy options to steer them toward favorable energy outcomes. Current CAV modeling challenges include estimating behavior change, understanding potential vehicle-to-vehicle interactions, and assessing traffic flow and vehicle use under different automation scenarios. To bridge these gaps and develop a picture of potential future automated systems, NREL is integrating existing modeling capabilities with additional tools and data inputs to create a more fully integrated CAV assessment toolkit.

  1. Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode

    SciTech Connect (OSTI)

    Pigarov, A. Yu.; Krasheninnikov, S. I.; Hollmann, E. M. [University of California at San Diego, La Jolla, California 92093 (United States); Rognlien, T. D.; Lasnier, C. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Unterberg, E. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-06-15T23:59:59.000Z

    Simulations of a high-confinement-mode (H-mode) tokamak discharge with infrequent giant type-I ELMs are performed by the multi-fluid, multi-species, two-dimensional transport code UEDGE-MB, which incorporates the Macro-Blob approach for intermittent non-diffusive transport due to filamentary coherent structures observed during the Edge Localized Modes (ELMs) and simple time-dependent multi-parametric models for cross-field plasma transport coefficients and working gas inventory in material surfaces. Temporal evolutions of pedestal plasma profiles, divertor recycling, and wall inventory in a sequence of ELMs are studied and compared to the experimental time-dependent data. Short- and long-time-scale variations of the pedestal and divertor plasmas where the ELM is described as a sequence of macro-blobs are discussed. It is shown that the ELM recovery includes the phase of relatively dense and cold post-ELM divertor plasma evolving on a several ms scale, which is set by the transport properties of H-mode barrier. The global gas balance in the discharge is also analyzed. The calculated rates of working gas deposition during each ELM and wall outgassing between ELMs are compared to the ELM particle losses from the pedestal and neutral-beam-injection fueling rate, correspondingly. A sensitivity study of the pedestal and divertor plasmas to model assumptions for gas deposition and release on material surfaces is presented. The performed simulations show that the dynamics of pedestal particle inventory is dominated by the transient intense gas deposition into the wall during each ELM followed by continuous gas release between ELMs at roughly a constant rate.

  2. Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode

    SciTech Connect (OSTI)

    Pigarov, A. Yu. [University of California, San Diego; Krasheninnikov, S. I. [University of California, La Jolla; Rognlien, T. D. [Lawrence Livermore National Laboratory (LLNL); Hollmann, E. M. [University of California, San Diego; Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Unterberg, Ezekial A [ORNL

    2014-01-01T23:59:59.000Z

    Simulations of a high-confinement-mode (H-mode) tokamak discharge with infrequent giant type-I ELMs are performed by the multi-fluid, multi-species, two-dimensional transport code UEDGE-MB, which incorporates the Macro-Blob approach for intermittent non-diffusive transport due to filamentary coherent structures observed during the Edge Localized Modes (ELMs) and simple time-dependent multi-parametric models for cross-field plasma transport coefficients and working gas inventory in material surfaces. Temporal evolutions of pedestal plasma profiles, divertor recycling, and wall inventory in a sequence of ELMs are studied and compared to the experimental time-dependent data. Short- and long-time-scale variations of the pedestal and divertor plasmas where the ELM is described as a sequence of macro-blobs are discussed. It is shown that the ELM recovery includes the phase of relatively dense and cold post-ELM divertor plasma evolving on a several ms scale, which is set by the transport properties of H-mode barrier. The global gas balance in the discharge is also analyzed. The calculated rates of working gas deposition during each ELM and wall outgassing between ELMs are compared to the ELM particle losses from the pedestal and neutral-beam-injection fueling rate, correspondingly. A sensitivity study of the pedestal and divertor plasmas to model assumptions for gas deposition and release on material surfaces is presented. The performed simulations show that the dynamics of pedestal particle inventory is dominated by the transient intense gas deposition into the wall during each ELM followed by continuous gas release between ELMs at roughly a constant rate.

  3. PARTICLE TRANSPORTATION AND DEPOSITION IN HOT GAS FILTER VESSELS - A COMPUTATIONAL AND EXPERIMENTAL MODELING APPROACH

    SciTech Connect (OSTI)

    Goodarz Ahmadi

    2002-07-01T23:59:59.000Z

    In this project, a computational modeling approach for analyzing flow and ash transport and deposition in filter vessels was developed. An Eulerian-Lagrangian formulation for studying hot-gas filtration process was established. The approach uses an Eulerian analysis of gas flows in the filter vessel, and makes use of the Lagrangian trajectory analysis for the particle transport and deposition. Particular attention was given to the Siemens-Westinghouse filter vessel at Power System Development Facility in Wilsonville in Alabama. Details of hot-gas flow in this tangential flow filter vessel are evaluated. The simulation results show that the rapidly rotation flow in the spacing between the shroud and the vessel refractory acts as cyclone that leads to the removal of a large fraction of the larger particles from the gas stream. Several alternate designs for the filter vessel are considered. These include a vessel with a short shroud, a filter vessel with no shroud and a vessel with a deflector plate. The hot-gas flow and particle transport and deposition in various vessels are evaluated. The deposition patterns in various vessels are compared. It is shown that certain filter vessel designs allow for the large particles to remain suspended in the gas stream and to deposit on the filters. The presence of the larger particles in the filter cake leads to lower mechanical strength thus allowing for the back-pulse process to more easily remove the filter cake. A laboratory-scale filter vessel for testing the cold flow condition was designed and fabricated. A laser-based flow visualization technique is used and the gas flow condition in the laboratory-scale vessel was experimental studied. A computer model for the experimental vessel was also developed and the gas flow and particle transport patterns are evaluated.

  4. A transmission/escape probabilities model for neutral particle transport in the outer regions of a diverted tokamak

    SciTech Connect (OSTI)

    Stacey, W.M.

    1992-12-01T23:59:59.000Z

    A new computational model for neutral particle transport in the outer regions of a diverted tokamak plasma chamber is presented. The model is based on the calculation of transmission and escape probabilities using first-flight integral transport theory and the balancing of fluxes across the surfaces bounding the various regions. The geometrical complexity of the problem is included in precomputed probabilities which depend only on the mean free path of the region.

  5. REPRESENTING AEROSOL DYNAMICS AND PROPERTIES IN CHEMICAL TRANSPORT MODELS BY THE METHOD OF MOMENTS.

    SciTech Connect (OSTI)

    SCHWARTZ,S.E.; MCGRAW,R.; BENKOVITZ,C.M.; WRIGHT,D.L.

    2001-04-01T23:59:59.000Z

    Atmospheric aerosols, suspensions of solid or liquid particles, are an important multi-phase system. Aerosols scatter and absorb shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility; nucleate cloud droplet formation, modifying the reflectivity of clouds (Twomey et al., 1984; Schwartz and Slingo, 1996) as well as contributing to composition of cloudwater and to wet deposition (Seinfeld and Pandis, 1998); and affect human health through inhalation (NRC, 1998). Existing and prospective air quality regulations impose standards on concentrations of atmospheric aerosols to protect human health and welfare (EPA, 1998). Chemical transport and transformation models representing the loading and geographical distribution of aerosols and precursor gases are needed to permit development of effective and efficient strategies for meeting air quality standards, and for examining aerosol effects on climate retrospectively and prospectively for different emissions scenarios. Important aerosol properties and processes depend on their size distribution: light scattering, cloud nucleating properties, dry deposition, and penetration into airways of lungs. The evolution of the mass loading itself depends on particle size because of the size dependence of growth and removal processes. For these reasons it is increasingly recognized that chemical transport and transformation models must represent not just the mass loading of atmospheric particulate matter but also the aerosol microphysical properties and the evolution of these properties if aerosols are to be accurately represented in these models. If the size distribution of the aerosol is known, a given property can be evaluated as the integral of the appropriate kernel function over the size distribution. This has motivated the approach of determining aerosol size distribution, and of explicitly representing this distribution and its evolution in chemical transport models.

  6. Groundwater Fate and Transport Modeling for Texarkana Wood Preserving Company Superfund Site, Texarkana, Texas

    SciTech Connect (OSTI)

    Arnett, Ronald Chester

    1999-08-01T23:59:59.000Z

    Fate and transport model results are presented for the Texarkana Wood Preserving Company (TWPC)superfund site. The conceptual model assumes two sources of contamination, specifically, the areas around the old and new process areas. Recent data show the presence of non-aqueous phase liquids (NAPL) in the aquifer that are also sources of dissolved contamination in the aquifer. A flow model was constructed and calibrated against measured hydraulic heads at permanent monitoring wells. Good matches were obtained between model simulated heads and most measured heads. An unexplained exception occurs at monitoring well MW-13 down gradient of the site beyond the measured contaminant plume where the model predicts heads that are more than 2 ft. lower than reported field measurements. Adjusting hydraulic parameters in the model could not account for this anomaly and still preserve the head matches at other wells. There is likely a moderate deficiency in the conceptual model or perhaps a data error. Other information such as substantial amounts of infiltrating surface water in the area or a correction in surveyed elevation would improve the flow model. A particle tracking model calculated a travel time from the new process area to the Day’s Creek discharge location on the order of 40 years. Travel times from the old process area to Day’s Creek were calculated to be on the order of 80 years. While these calculations are subject to some uncertainty, travel times of decades are indicated.

  7. Transportation | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Transportation From modeling and simulation programs to advanced electric powertrains, engines, biofuels, lubricants, and batteries, Argonne's transportation research is vital to...

  8. Laboratory Studies of the Reactive Chemistry and Changing CCN Properties of Secondary Organic Aerosol, Including Model Development

    SciTech Connect (OSTI)

    Scot Martin

    2013-01-31T23:59:59.000Z

    The chemical evolution of secondary-organic-aerosol (SOA) particles and how this evolution alters their cloud-nucleating properties were studied. Simplified forms of full Koehler theory were targeted, specifically forms that contain only those aspects essential to describing the laboratory observations, because of the requirement to minimize computational burden for use in integrated climate and chemistry models. The associated data analysis and interpretation have therefore focused on model development in the framework of modified kappa-Koehler theory. Kappa is a single parameter describing effective hygroscopicity, grouping together several separate physicochemical parameters (e.g., molar volume, surface tension, and van't Hoff factor) that otherwise must be tracked and evaluated in an iterative full-Koehler equation in a large-scale model. A major finding of the project was that secondary organic materials produced by the oxidation of a range of biogenic volatile organic compounds for diverse conditions have kappa values bracketed in the range of 0.10 +/- 0.05. In these same experiments, somewhat incongruently there was significant chemical variation in the secondary organic material, especially oxidation state, as was indicated by changes in the particle mass spectra. Taken together, these findings then support the use of kappa as a simplified yet accurate general parameter to represent the CCN activation of secondary organic material in large-scale atmospheric and climate models, thereby greatly reducing the computational burden while simultaneously including the most recent mechanistic findings of laboratory studies.

  9. Thermochemical process for seasonal storage of solar energy: characterization and modeling of a high-density reactive bed

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Thermochemical process for seasonal storage of solar energy: characterization and modeling to maximize the use of solar energy for house heating, it is interesting to valorize the solar energy excess efficiency, and a 20 per cent share of renewable). The use of renewable energies and in particular solar

  10. Angular momentum transport modeling: achievements of a gyrokinetic quasi-linear approach

    E-Print Network [OSTI]

    Cottier, P; Camenen, Y; Gurcan, O D; Casson, F J; Garbet, X; Hennequin, P; Tala, T

    2014-01-01T23:59:59.000Z

    QuaLiKiz, a model based on a local gyrokinetic eigenvalue solver is expanded to include momentum flux modeling in addition to heat and particle fluxes. Essential for accurate momentum flux predictions, the parallel asymmetrization of the eigenfunctions is successfully recovered by an analytical fluid model. This is tested against self-consistent gyrokinetic calculations and allows for a correct prediction of the ExB shear impact on the saturated potential amplitude by means of a mixing length rule. Hence, the effect of the ExB shear is recovered on all the transport channels including the induced residual stress. Including these additions, QuaLiKiz remains ~10 000 faster than non-linear gyrokinetic codes allowing for comparisons with experiments without resorting to high performance computing. The example is given of momentum pinch calculations in NBI modulation experiments.

  11. Modeling of the recycling particle flux and electron particle transport in the DIII-D tokamak

    SciTech Connect (OSTI)

    Baker, D.R.; Jackson, G.L. [General Atomics, San Diego, CA (United States); Maingi, R. [Oak Ridge Associated Universities, Inc., TN (United States); Owen, L.W. [Oak Ridge National Lab., TN (United States); Porter, G.D. [Lawrence Livermore National Lab., CA (United States)

    1996-10-01T23:59:59.000Z

    One of the most difficult aspects of performing an equilibrium particle transport analysis in a diverted tokamak is the determination of the particle flux which enters the plasma after recycling from the divertor plasma, the divertor target plates or the vessel wall. An approach which has been utilized in the past is to model the edge, scrape-off layer (SOL), and divertor plasma to match measured plasma parameters and then use a neutral transport code to obtain an edge recycling flux while trying to match the measured divertor D(x emissivity. Previous simulations were constrained by electron density (n{sub e}) and temperature (T{sub e}), ion temperature (T{sub i}) data at the outer midplane, divertor heat flux from infrared television cameras, and n{sub e}, T{sub e} and particle flux at the target from fixed Langmuir probes, along with the divertor D{sub {alpha}} emissivity. In this paper, we present results of core fueling calculations from the 2-D modeling for ELM-free discharges, constrained by data from the new divertor diagnostics. In addition, we present a simple technique for estimating the recycling flux just after the L-H transition and demonstrate how this technique is supported by the detailed modeling. We will show the effect which inaccuracies in the recycling flux have on the calculated particle flux in the plasma core. For some specific density profiles, it is possible to separate the convective flux from the conductive flux. The diffusion coefficients obtained show a sharp decrease near a normalized radius of 0.9 indicating the presence of a transport barrier.

  12. Initialization of hydrodynamics in relativistic heavy ion collisions with an energy-momentum transport model

    E-Print Network [OSTI]

    V. Yu. Naboka; S. V. Akkelin; Iu. A. Karpenko; Yu. M. Sinyukov

    2015-01-14T23:59:59.000Z

    A key ingredient of hydrodynamical modeling of relativistic heavy ion collisions is thermal initial conditions, an input that is the consequence of a pre-thermal dynamics which is not completely understood yet. In the paper we employ a recently developed energy-momentum transport model of the pre-thermal stage to study influence of the alternative initial states in nucleus-nucleus collisions on flow and energy density distributions of the matter at the starting time of hydrodynamics. In particular, the dependence of the results on isotropic and anisotropic initial states is analyzed. It is found that at the thermalization time the transverse flow is larger and the maximal energy density is higher for the longitudinally squeezed initial momentum distributions. The results are also sensitive to the relaxation time parameter, equation of state at the thermalization time, and transverse profile of initial energy density distribution: Gaussian approximation, Glauber Monte Carlo profiles, etc. Also, test results ensure that the numerical code based on the energy-momentum transport model is capable of providing both averaged and fluctuating initial conditions for the hydrodynamic simulations of relativistic nuclear collisions.

  13. Mesoscopic modeling of multi-physicochemical transport phenomena in porous media

    SciTech Connect (OSTI)

    Kang, Qinjin [Los Alamos National Laboratory; Wang, Moran [Los Alamos National Laboratory; Mukherjee, Partha P [Los Alamos National Laboratory; Lichtner, Peter C [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    We present our recent progress on mesoscopic modeling of multi-physicochemical transport phenomena in porous media based on the lattice Boltzmann method. Simulation examples include injection of CO{sub 2} saturated brine into a limestone rock, two-phase behavior and flooding phenomena in polymer electrolyte fuel cells, and electroosmosis in homogeneously charged porous media. It is shown that the lattice Boltzmann method can account for multiple, coupled physicochemical processes in these systems and can shed some light on the underlying physics occuning at the fundamental scale. Therefore, it can be a potential powerful numerical tool to analyze multi-physicochemical processes in various energy, earth, and environmental systems.

  14. Workshop on Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials

    SciTech Connect (OSTI)

    Giles, GE

    2005-02-03T23:59:59.000Z

    The purpose of this Workshop on ''Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials'' was to solicit functional requirements for tools that help Incident Managers plan for and deal with the consequences of industrial or terrorist releases of materials into the nation's waterways and public water utilities. Twenty representatives attended and several made presentations. Several hours of discussions elicited a set of requirements. These requirements were summarized in a form for the attendees to vote on their highest priority requirements. These votes were used to determine the prioritized requirements that are reported in this paper and can be used to direct future developments.

  15. Asymmetric quantum transport in a double-stranded Kronig-Penney model

    E-Print Network [OSTI]

    Taksu Cheon; Sergey S. Poghosyan

    2015-03-03T23:59:59.000Z

    We introduce a double-stranded Kronig-Penney model and analyze its transport properties. The asymmetric fluxes between two strands with suddenly alternating localization patterns are found as the energy is varied. The zero-size limit of the internal lines connecting two strands is examined using quantum graph vertices with four edges. We also consider a two-dimensional Kronig-Penney lattice with two types of alternating layers with $\\delta$ and $\\delta'$ connections, and show that the existence of energy bands in which the quantum flux can flow only in selected directions.

  16. The freeze-out properties of hyperons in a microscopic transport model

    E-Print Network [OSTI]

    Xie, Zhenglian; Bass, Steffen A

    2009-01-01T23:59:59.000Z

    The excitation function of freeze-out time, average freeze-out temperature and freeze-out energy density of (multi-) strange baryons created in relativistic heavy-ion collisions is investigated in the framework of a microscopic transport model. We find that the Omega on average freezes out earlier than the nucleon, Xi and Lambda. The average freeze-out temperature and energy density as well as the spread between the different baryonicstates increase monotonously with increasing beam energy and should approach a universal value in the case of a hadronizing Quark-Gluon-Plasma.

  17. The freeze-out properties of hyperons in a microscopic transport model

    E-Print Network [OSTI]

    Zhenglian Xie; Pingzhi Ning; Steffen A. Bass

    2009-11-23T23:59:59.000Z

    The excitation function of freeze-out time, average freeze-out temperature and freeze-out energy density of (multi-) strange baryons created in relativistic heavy-ion collisions is investigated in the framework of a microscopic transport model. We find that the Omega on average freezes out earlier than the nucleon, Xi and Lambda. The average freeze-out temperature and energy density as well as the spread between the different baryonicstates increase monotonously with increasing beam energy and should approach a universal value in the case of a hadronizing Quark-Gluon-Plasma.

  18. Constraint-Based Routing Models for the Transport of Radioactive Materials

    SciTech Connect (OSTI)

    Peterson, Steven K [ORNL

    2015-01-01T23:59:59.000Z

    The Department of Energy (DOE) has a historic programmatic interest in the safe and secure routing, tracking, and transportation risk analysis of radiological materials in the United States. In order to address these program goals, DOE has funded the development of several tools and related systems designed to provide insight to planners and other professionals handling radioactive materials shipments. These systems include the WebTRAGIS (Transportation Routing Analysis Geographic Information System) platform. WebTRAGIS is a browser-based routing application developed at Oak Ridge National Laboratory (ORNL) focused primarily on the safe transport of spent nuclear fuel from US nuclear reactors via railway, highway, or waterway. It is also used for the transport planning of low-level radiological waste to depositories such as the Waste Isolation Pilot Plant (WIPP) facility. One particular feature of WebTRAGIS is its coupling with high-resolution population data from ORNL s LandScan project. This allows users to obtain highly accurate population count and density information for use in route planning and risk analysis. To perform the routing and risk analysis WebTRAGIS incorporates a basic routing model methodology, with the additional application of various constraints designed to mimic US Department of Transportation (DOT), DOE, and Nuclear Regulatory Commission (NRC) regulations. Aside from the routing models available in WebTRAGIS, the system relies on detailed or specialized modal networks for the route solutions. These include a highly detailed network model of the US railroad system, the inland and coastal waterways, and a specialized highway network that focuses on the US interstate system and the designated hazardous materials and Highway Route Controlled Quantity (HRCQ) -designated roadways. The route constraints in WebTRAGIS rely upon a series of attributes assigned to the various components of the different modal networks. Routes are determined via a constrained shortest-path Dijkstra algorithm that has an assigned impedance factor. The route constraints modify the various impedance weights to bias or prefer particular network characteristics as desired by the user. Both the basic route model and the constrained impedance function calculations are determined by a series of network characteristics and shipment types. The study examines solutions under various constraints modeled by WebTRAGIS including possible routes from select shut-down reactor sites in the US to specific locations in the US. For purposes of illustration, the designated destinations are Oak Ridge National Laboratory in Tennessee and the Savannah River Site in South Carolina. To the degree that routes express sameness or variety under constraints serves to illustrate either a) the determinism of particular transport modes by either configuration or regulatory compliance, and/or b) the variety of constrained routes that are regulation compliant but may not be operationally feasible.

  19. Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

    SciTech Connect (OSTI)

    B.D. Wood

    2007-01-01T23:59:59.000Z

    Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role of flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes. The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologically-reduced sediments (with respect to re-oxidation by convective fluxes of O2 and NO3-) and the long-term stability of immobilized uranium mineral phases after bioremediation processes are complete, and (4) the ability for metabolic uncoupling compounds to maintain microbial growth while limiting biomass production. The results of the laboratory experiments will be used to develop mathematical descriptive models for the coupled transport and reduction processes.

  20. Application of Partial-Order Methods to Reactive Programs with Event Memorization

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    with event memorization. The reactive systems are specified with an asynchronous reactive language Electre, 3 (2001) 287-316" #12;2 Electre: an Asynchronous Reactive Language with Event Memorization 3 2 of a semantic model of an asyn- chronous reactive language: Electre [PRH92, CR95]. Indeed, this language

  1. Development of a Hydrodynamic and Transport model of Bellingham Bay in Support of Nearshore Habitat Restoration

    SciTech Connect (OSTI)

    Wang, Taiping; Yang, Zhaoqing; Khangaonkar, Tarang

    2010-04-22T23:59:59.000Z

    In this study, a hydrodynamic model based on the unstructured-grid finite volume coastal ocean model (FVCOM) was developed for Bellingham Bay, Washington. The model simulates water surface elevation, velocity, temperature, and salinity in a three-dimensional domain that covers the entire Bellingham Bay and adjacent water bodies, including Lummi Bay, Samish Bay, Padilla Bay, and Rosario Strait. The model was developed using Pacific Northwest National Laboratory’s high-resolution Puget Sound and Northwest Straits circulation and transport model. A sub-model grid for Bellingham Bay and adjacent coastal waters was extracted from the Puget Sound model and refined in Bellingham Bay using bathymetric light detection and ranging (LIDAR) and river channel cross-section data. The model uses tides, river inflows, and meteorological inputs to predict water surface elevations, currents, salinity, and temperature. A tidal open boundary condition was specified using standard National Oceanic and Atmospheric Administration (NOAA) predictions. Temperature and salinity open boundary conditions were specified based on observed data. Meteorological forcing (wind, solar radiation, and net surface heat flux) was obtained from NOAA real observations and National Center for Environmental Prediction North American Regional Analysis outputs. The model was run in parallel with 48 cores using a time step of 2.5 seconds. It took 18 hours of cpu time to complete 26 days of simulation. The model was calibrated with oceanographic field data for the period of 6/1/2009 to 6/26/2009. These data were collected specifically for the purpose of model development and calibration. They include time series of water-surface elevation, currents, temperature, and salinity as well as temperature and salinity profiles during instrument deployment and retrieval. Comparisons between model predictions and field observations show an overall reasonable agreement in both temporal and spatial scales. Comparisons of root mean square error values for surface elevation, velocity, temperature, and salinity time series are 0.11 m, 0.10 m/s, 1.28oC, and 1.91 ppt, respectively. The model was able to reproduce the salinity and temperature stratifications inside Bellingham Bay. Wetting and drying processes in tidal flats in Bellingham Bay, Samish Bay, and Padilla Bay were also successfully simulated. Both model results and observed data indicated that water surface elevations inside Bellingham Bay are highly correlated to tides. Circulation inside the bay is weak and complex and is affected by various forcing mechanisms, including tides, winds, freshwater inflows, and other local forcing factors. The Bellingham Bay model solution was successfully linked to the NOAA oil spill trajectory simulation model “General NOAA Operational Modeling Environment (GNOME).” Overall, the Bellingham Bay model has been calibrated reasonably well and can be used to provide detailed hydrodynamic information in the bay and adjacent water bodies. While there is room for further improvement with more available data, the calibrated hydrodynamic model provides useful hydrodynamic information in Bellingham Bay and can be used to support sediment transport and water quality modeling as well as assist in the design of nearshore restoration scenarios.

  2. Three-dimensional transport and concentration of SF{sub 6} - a model intercomparison study (transcom 2)

    SciTech Connect (OSTI)

    Denning, A.S.; Holzer, M.; Burney, K.R.; Heimann, M.; Law, R.M.; Rayner, P.J.; Fund, I.Y.; Fan, S.M.; Taguchi, S.; Friedlingstein, P.; Balkanski, Y.; Taylor, J.; Maiss, M.; Levin, I.

    1999-01-02T23:59:59.000Z

    Sulfur hexafluoride (SF6) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF, for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the differences among the simulations. Most of the models are reasonably successful at simulating the observed meridional gradient of SF6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change From station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to which resolved advection vs. parameterized diffusion accomplishes the meridional transport of SF6. Observational programs could provide a much better constraint on simulated chemical tracer transport if they included regular sampling of vertical profiles of nonreactive trace gases over source regions and meridional profiles in the middle to upper troposphere. Further analysis of the SF6 simulations will focus on the subgrid-scale parameterized transports.

  3. International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR MODELLING FOR LIGHT VEHICLES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    - 1 - 16th International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR in Europe: The European MEET (Methodologies for Estimating air pollutant Emissions from Transport) project. Transport and Air Pollution, Graz : Austria (2008)" #12;- 2 - 16th International Conference 'Transport

  4. Streambank Stability: Modeling Channel Evolution and Pollutant Transport in an Urban Stream

    E-Print Network [OSTI]

    Clark, Shirley E.

    ­ Harrisburg, Middletown, PA 17057 Abstract This study evaluates the channel evolution and transport capacity

  5. A Complete Transport Validated Model on a Zeolite Membrane for Carbon Dioxide Permeance and Capture

    E-Print Network [OSTI]

    Gkanas, Evangelos I; Stubos, Athanasios K; Makridis, Sofoklis S

    2013-01-01T23:59:59.000Z

    The CO2 emissions from major industries cause serious global environment problems and their mitigation is urgently needed. The use of zeolite membranes is a very efficient way in order to capture CO2 from some flue gases. The dominant transport mechanism at low temperature andor high pressure is the diffusion through the membrane. This procedure can be divided in three steps: Adsorption of the molecules of the species in the surface of the membrane, then a driving force gives a path where the species follow inside the membrane and finally the species desorbed from the surface of the membrane. The current work is aimed at developing a simulation model for the CO2 transport through a zeolite membrane and estimate the diffusion phenomenon through a very thin membrane of 150 nm in a Wicke-Kallenbach cell. The cell is cylindrical in shape with diameter of 19 mm and consists of a retentate gas chamber, a permeate gas chamber which are separated by a cylindrical zeolite membrane. This apparatus have been modeled wit...

  6. Comparison of surface meteorological data representativeness for the Weldon Spring transport and dispersion modeling analysis

    SciTech Connect (OSTI)

    Lazaro, M.

    1989-06-01T23:59:59.000Z

    The US Department of Energy is conducting the Weldon Spring Site Remedial Action Project under the Surplus Facilities Management Program (SFMP). The major goals of the SFMP are to eliminate potential hazards to the public and the environment that associated with contamination at SFMP sites and to make surplus property available for other uses to the extent possible. This report presents the results of analysis of available meteorological data from stations near the Weldon Spring site. Data that are most representative of site conditions are needed to accurately model the transport and dispersion of air pollutants associated with remedial activities. Such modeling will assist the development of mitigative measures. 17 refs., 12 figs., 6 tabs.

  7. A model for motor-mediated bidirectional transport along an antipolar microtubule bundle

    E-Print Network [OSTI]

    Congping Lin; Peter Ashwin; Gero Steinberg

    2012-11-21T23:59:59.000Z

    Long-distance bidirectional transport of organelles depends on the motor proteins kinesin and dynein. Using quantitative data obtained from a fungal model system, we previously developed ASEP-models of bidirectional motion of motors along unipolar microtubules (MTs) near the cell ends of the elongated hyphal cells (herein referred as "unipolar section"). However, recent quantitative live cell imaging in this system has demonstrated that long-range motility of motors and their endosomal cargo mainly occurs along extended antipolar microtubule bundles within the central part of the cell (herein referred to as "bipolar section"). Dynein and kinesin-3 motors coordinate their activity to move early endosomes (EEs) in a bidirectional fashion, with dynein mediating retrograde motility along the unipolar section near the cell poles, whereas kinesin-3 is responsible for bidirectional motions along the antipolar section. Here we extend our modelling approach to simulate bidirectional motility along an antipolar microtubule bundle. In our model, cargos (particles) change direction on each MT with a turning rate $\\Omega$ and the MTs are linked to each other at the minus ends where particles can hop between MTs with a rate $q_1$ (obstacle-induced switching rate) or $q_2$ (end-induced switching rate). By numerical simulations and mean-field approximations, we investigate the distribution of particles along the MTs for different overall densities $\\Theta$. We find that even if $\\Theta$ is low, the system can exhibit shocks in the density profiles near plus and minus ends caused by queueing of particles. We also discuss how the switching rates $q_{1,2}$ influence the type of motor that dominates the active transport in the bundle.

  8. THE APPLICATION OF THE LAND TRANSFORMATION, GROUNDWATER FLOW AND SOLUTE TRANSPORT MODELS FOR MICHIGAN'S GRAND TRAVERSE BAY

    E-Print Network [OSTI]

    1 THE APPLICATION OF THE LAND TRANSFORMATION, GROUNDWATER FLOW AND SOLUTE TRANSPORT MODELS). The two hydrogeologic models that are being used here allow us to explore the dynamics of groundwater flow Meeting, New Orleans, Louisiana, March 14, 2001. #12;2 INTRODUCTION Grand Traverse Bay and the Grand

  9. Mesoscale Phase-Field Modeling of Charge Transport in Nanocomposite Electrodes for Lithium-ion Batteries

    SciTech Connect (OSTI)

    Hu, Shenyang Y.; Li, Yulan; Rosso, Kevin M.; Sushko, Maria L.

    2013-01-10T23:59:59.000Z

    A phase-field model is developed to investigate the influence of microstructure, thermodynamic and kinetic properties, and charging conditions on charged particle transport in nanocomposite electrodes. Two sets of field variables are used to describe the microstructure. One is comprised of the order parameters describing size, orientation and spatial distributions of nanoparticles, and the other is comprised of the concentrations of mobile species. A porous nanoparticle microstructure filled with electrolyte is taken as a model system to test the phase-field model. Inhomogeneous and anisotropic dielectric constants and mobilities of charged particles, and stresses associated with lattice deformation due to Li-ion insertion/extraction are considered in the model. Iteration methods are used to find the elastic and electric fields in an elastically and electrically inhomogeneous medium. The results demonstrate that the model is capable of predicting charge separation associated with the formation of a double layer at the electrochemical interface between solid and electrolyte, and the effect of microstructure, inhomogeneous and anisotropic thermodynamic and kinetic properties, charge rates, and stresses on voltage versus current density and capacity during charging and discharging.

  10. Reactive Power Compensator.

    DOE Patents [OSTI]

    El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

    1992-07-28T23:59:59.000Z

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

  11. Reactive power compensator

    DOE Patents [OSTI]

    El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Woodinville, WA); Chen, Mingliang (Kirkland, WA); Andexler, George (Everett, WA); Huang, Tony (Seattle, WA)

    1992-01-01T23:59:59.000Z

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  12. Comprehensive inverse modeling for the study of carrier transport models in sub-50nm MOSFETs

    E-Print Network [OSTI]

    Djomehri, Ihsan Jahed, 1976-

    2002-01-01T23:59:59.000Z

    Direct quantitative 2-D characterization of sub-50 nm MOSFETs continues to be elusive. This research develops a comprehensive indirect inverse modeling technique for extracting 2-D device topology using combined log(I)-V ...

  13. Modeling of particle and energy transport in the edge plasma of Alcator C-Mod

    SciTech Connect (OSTI)

    Umansky, M.V.; Krasheninnikov, S.I.; LaBombard, B.; Lipschultz, B.; Terry, J.L. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1999-07-01T23:59:59.000Z

    In the present study recycling and transport in the edge plasma of Alcator C-Mod [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] is modeled and analyzed with the multi-fluid code UEDGE [T. D. Rognlien {ital et al.}, J. Nucl. Mater. {bold 196{endash}198}, 347 (1992)]. Matching the experimental plasma density profiles in the scrape-off layer (SOL) requires a spatially dependent effective anomalous diffusion coefficient D{sub {perpendicular}} growing rapidly towards the wall. The midplane pressure of neutral gas, P{sub mid}, is a key parameter that reflects the magnitude of anomalous transport of plasma from the core. Recycling of plasma on the main chamber wall appears to be quite significant, especially in the case of high P{sub mid}{approximately}0.3 mTorr when the main wall provides {approximately}70{percent} of recycling neutrals in the main chamber. In the upper SOL (well above the {ital x} point) draining of particles by the poloidal flow is weak and thus the particle balance is predominantly radial. For the radial heat transport it is found that energy flux carried by radial plasma convection and by charge-exchange (CX) neutrals is quite significant in SOL. In the high P{sub mid} case, heat conduction by CX neutrals along with radial heat convection by plasma carries most of the power flux ({approximately}75{percent}) across the last closed flux surface. Even in the low P{sub mid} case, heat conduction by CX neutrals dominates the radial heat flux far out in the SOL. {copyright} {ital 1999 American Institute of Physics.}

  14. A coarse-grained transport model for neutral particles in turbulent plasmas

    SciTech Connect (OSTI)

    Mekkaoui, A.; Reiter, D.; Boerner, P. [IEK-4 Plasmaphysik, Forschungszentrum Juelich GmbH, Euratom Association, D-52425 Juelich (Germany); Marandet, Y.; Genesio, P.; Rosato, J.; Capes, H.; Koubiti, M.; Godbert-Mouret, L.; Stamm, R. [Aix-Marseille Universite, CNRS, PIIM, UMR 7345, F-13397 Marseille Cedex 20 (France)

    2012-12-15T23:59:59.000Z

    The transport of neutral particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for neutral particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D{sub 2} molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.

  15. Transport theory for cold relativistic superfluids from an analogue model of gravity

    E-Print Network [OSTI]

    Massimo Mannarelli; Cristina Manuel

    2008-02-04T23:59:59.000Z

    We write a covariant transport equation for the phonon excitations of a relativistic superfluid valid at small temperatures. The hydrodynamical equations for this system are derived from the effective field theory associated to the superfluid phonons. We describe how to construct the kinetic theory for the phonon quasiparticles using a relativistic generalization of the analogue model of gravity developed by Unruh. This gravity analogy relies on the equivalence between the action of a phonon field moving in a superfluid background with that of a boson propagating in a given curved space-time. Exploiting this analogy we obtain continuity equations for the phonon current, entropy and energy-momentum tensor in a covariant form, valid in any reference frame. Our aim is to shed light on some aspects of transport phenomena of relativistic superfluidity. In particular, we are interested in the low temperature regime of the color flavor locked phase, which is a color superconducting and superfluid phase of high density QCD that may be realized in the core of neutron stars.

  16. Correcting transport errors during advection of aerosol and cloud moment sequences in eulerian models

    SciTech Connect (OSTI)

    McGraw R.

    2012-03-01T23:59:59.000Z

    Moment methods are finding increasing usage for simulations of particle population balance in box models and in more complex flows including two-phase flows. These highly efficient methods have nevertheless had little impact to date for multi-moment representation of aerosols and clouds in atmospheric models. There are evidently two reasons for this: First, atmospheric models, especially if the goal is to simulate climate, tend to be extremely complex and take many man-years to develop. Thus there is considerable inertia to the implementation of novel approaches. Second, and more fundamental, the nonlinear transport algorithms designed to reduce numerical diffusion during advection of various species (tracers) from cell to cell, in the typically coarse grid arrays of these models, can and occasionally do fail to preserve correlations between the moments. Other correlated tracers such as isotopic abundances, composition of aerosol mixtures, hydrometeor phase, etc., are subject to this same fate. In the case of moments, this loss of correlation can and occasionally does give rise to unphysical moment sets. When this happens the simulation can come to a halt. Following a brief description and review of moment methods, the goal of this paper is to present two new approaches that both test moment sequences for validity and correct them when they fail. The new approaches work on individual grid cells without requiring stored information from previous time-steps or neighboring cells.

  17. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 3

    SciTech Connect (OSTI)

    NONE

    1998-01-01T23:59:59.000Z

    This Appendix consists of two unpublished reports produced by Energy and Environmental Analysis, Inc., under contract to Oak Ridge National Laboratory. These two reports formed the basis for the subsequent development of the Fuel Economy Model described in Volume 1. They are included in order to document more completely the efforts undertaken to construct a comprehensive model of automobile fuel economy. The supplemental reports are as follows: Supplement 1--Documentation Attributes of Technologies to Improve Automotive Fuel Economy; Supplement 2--Analysis of the Fuel Economy Boundary for 2010 and Comparison to Prototypes.

  18. Modeling regional transportation demand in China and the impacts of a national carbon constraint

    E-Print Network [OSTI]

    Kishimoto, Paul

    2015-01-30T23:59:59.000Z

    Climate and energy policy in China will have important and uneven impacts on the country’s regionally heterogeneous transport system. In order to simulate these impacts, transport sector detail is added to a multi-sector, ...

  19. A general performance model for parallel sweeps on orthogonal grids for particle transport calculations

    E-Print Network [OSTI]

    Mathis, Mark Michael

    2000-01-01T23:59:59.000Z

    particle transport calculations is an important problem in many applications targeted by the Accelerated Strategic Computing Initiative of the United States Department of Energy. One common approach to deterministic particle transport calculations...

  20. Transport and seismoelectric properties of porous permeable rock : numerical modeling and laboratory measurements

    E-Print Network [OSTI]

    Zhan, Xin, Ph. D. Massachusetts Institute of Technology

    2010-01-01T23:59:59.000Z

    The objective of this thesis is to better understand the transport and seismoelectric (SE) properties of porous permeable rock. Accurate information of rock transport properties, together with pore geometry, can aid us to ...

  1. A Description of ELM-Free H-modes in Terms of a Neoclassical Edge Barrier and a ‘Mixed’ Model for Energy and Particle Transport

    E-Print Network [OSTI]

    A Description of ELM-Free H-modes in Terms of a Neoclassical Edge Barrier and a ‘Mixed’ Model for Energy and Particle Transport

  2. Modeling electronic structure and transport properties of graphene with resonant scattering centers

    E-Print Network [OSTI]

    Shengjun Yuan; Hans De Raedt; Mikhail I. Katsnelson

    2010-09-17T23:59:59.000Z

    We present a detailed numerical study of the electronic properties of single-layer graphene with resonant ("hydrogen") impurities and vacancies within a framework of noninteracting tight-binding model on a honeycomb lattice. The algorithms are based on the numerical solution of the time-dependent Schr\\"{o}dinger equation and applied to calculate the density of states, \\textit{quasieigenstates}, AC and DC conductivities of large samples containing millions of atoms. Our results give a consistent picture of evolution of electronic structure and transport properties of functionalized graphene in a broad range of concentration of impurities (from graphene to graphane), and show that the formation of impurity band is the main factor determining electrical and optical properties at intermediate impurity concentrations, together with a gap opening when approaching the graphane limit.

  3. Validation Analysis of the Groundwater Flow and Transport Model of the Central Nevada Test Area

    SciTech Connect (OSTI)

    A. Hassan; J. Chapman; H. Bekhit; B. Lyles; K. Pohlmann

    2006-09-30T23:59:59.000Z

    The Central Nevada Test Area (CNTA) is a U.S. Department of Energy (DOE) site undergoing environmental restoration. The CNTA is located about 95 km northeast of Tonopah, Nevada, and 175 km southwest of Ely, Nevada (Figure 1.1). It was the site of the Faultless underground nuclear test conducted by the U.S. Atomic Energy Commission (DOE's predecessor agency) in January 1968. The purposes of this test were to gauge the seismic effects of a relatively large, high-yield detonation completed in Hot Creek Valley (outside the Nevada Test Site [NTS]) and to determine the suitability of the site for future large detonations. The yield of the Faultless underground nuclear test was between 200 kilotons and 1 megaton (DOE, 2000). A three-dimensional flow and transport model was created for the CNTA site (Pohlmann et al., 1999) and determined acceptable by DOE and the Nevada Division of Environmental Protection (NDEP) for predicting contaminant boundaries for the site.

  4. Transport model analysis of the transverse momentum and rapidity dependence of pion interferometry at SPS energies

    E-Print Network [OSTI]

    Qingfeng Li; Marcus Bleicher; Xianglei Zhu; Horst Stoecker

    2006-12-07T23:59:59.000Z

    Based on the UrQMD transport model, the transverse momentum and the rapidity dependence of the Hanbury-Brown-Twiss (HBT) radii $R_L$, $R_O$, $R_S$ as well as the cross term $R_{OL}$ at SPS energies are investigated and compared with the experimental NA49 and CERES data. The rapidity dependence of the $R_L$, $R_O$, $R_S$ is weak while the $R_{OL}$ is significantly increased at large rapidities and small transverse momenta. The HBT "life-time" issue (the phenomenon that the calculated $\\sqrt{R_O^{2}-R_S^{2}}$ value is larger than the correspondingly extracted experimental data) is also present at SPS energies.

  5. Mixing Cell Model: A One-Dimensional Numerical Model for Assessment of Water Flow and Contaminant Transport in the Unsaturated Zone

    SciTech Connect (OSTI)

    A. S. Rood

    2010-10-01T23:59:59.000Z

    This report describes the Mixing Cell Model code, a one-dimensional model for water flow and solute transport in the unsaturated zone under steady-state or transient flow conditions. The model is based on the principles and assumptions underlying mixing cell model formulations. The unsaturated zone is discretized into a series of independent mixing cells. Each cell may have unique hydrologic, lithologic, and sorptive properties. Ordinary differential equations describe the material (water and solute) balance within each cell. Water flow equations are derived from the continuity equation assuming that unit-gradient conditions exist at all times in each cell. Pressure gradients are considered implicitly through model discretization. Unsaturated hydraulic conductivity and moisture contents are determined by the material-specific moisture characteristic curves. Solute transport processes include explicit treatment of advective processes, first-order chain decay, and linear sorption reactions. Dispersion is addressed through implicit and explicit dispersion. Implicit dispersion is an inherent feature of all mixing cell models and originates from the formulation of the problem in terms of mass balance around fully mixed volume elements. Expressions are provided that relate implicit dispersion to the physical dispersion of the system. Two FORTRAN codes were developed to solve the water flow and solute transport equations: (1) the Mixing-Cell Model for Flow (MCMF) solves transient water flow problems and (2) the Mixing Cell Model for Transport (MCMT) solves the solute transport problem. The transient water flow problem is typically solved first by estimating the water flux through each cell in the model domain as a function of time using the MCMF code. These data are stored in either ASCII or binary files that are later read by the solute transport code (MCMT). Code output includes solute pore water concentrations, water and solute inventories in each cell and at each specified output time, and water and solute fluxes through each cell and specified output time. Computer run times for coupled transient water flow and solute transport were typically several seconds on a 2 GHz Intel Pentium IV desktop computer. The model was benchmarked against analytical solutions and finite-element approximations to the partial differential equations (PDE) describing unsaturated flow and transport. Differences between the maximum solute flux estimated by the mixing-cell model and the PDE models were typically less than two percent.

  6. Transportation Secure Data Center: Real-world Data for Planning, Modeling, and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2015-01-01T23:59:59.000Z

    The Transportation Secure Data Center (TSDC) at www.nrel.gov/tsdc provides free, web-based access to detailed transportation data from a variety of travel surveys conducted across the nation. While preserving the privacy of survey participants, this online repository makes vital transportation data broadly available to users from the comfort of their own desks via a secure online connection.

  7. Mathematical transport modeling for determination of effectiveness of Kepone clean up activities in the James River estuary

    SciTech Connect (OSTI)

    Onishi, Y.

    1980-01-01T23:59:59.000Z

    During the period of 1966-1975, a highly chlorinated pesticide, Kepone, was discharged to the environment around Hopewell, Virginia. Much of the Kepone that reached the James River estuary was adsorbed by river sediment, becoming a long-term source of pollution. In order to identify an optimal location to remove Kepone from the river bed and to assess the effectiveness of the clean up activities to reduce the Kepone level in the river, the mathematical simulation of sediment and Kepone transport in the James River estuary was performed by applying the sediment-containment transport model, FETRA, to an 86-km river reach between Bailey and Burwell Bays. The FETRA code is an unsteady, two-dimensional, finite element interactions. The submodels are: (1) a sediment transport submodel, (2) a dissolved contaminant transport submodel, and (3) a particulate contaminant (contaminant adsorbed by sediment) transport submodel. FETRA also predicts changes in river bed conditions of sediment and contaminant. The value of applying models to dredging activity goes beyond this specific example. Through the sensitivity analysis, one can employ models to predict the most cost effective strategy for dredging. Properly constructed strategies will take advantage of river and coastal water dynamics to reduce the total volume of sediments to be dredged. Results of the simulation can also be used to predict subsequent environmental impacts.

  8. Numerical modeling of a thermohydrochemical (T-H-C) coupling and the implications to radionuclide transport.

    SciTech Connect (OSTI)

    Esh, D. W.; Scheetz, B. E.

    1999-09-21T23:59:59.000Z

    Thermohydrochemical (T-H-C) processes result from the placement of heat-generating radioactive materials in unsaturated, fractured geologic materials. The placement of materials in the proposed Yucca Mountain repository will result in complex environmental conditions. Simple models are developed liking the thermohydrological effects simulated with TOUGHZ to system chemistry, with an example presented for chloride. Perturbations to near-field chemistry could have a significant impact on the migration of actinides and fission products in geologic materials. Various conceptual models to represent fractures are utilized in TOUGHZ simulations of thermohydrological processes. The simulated moisture redistribution is then coupled to simple chemical models to demonstrate the potential magnitude of T-H-C processes. The concentration of chloride in solution (returning to the engineered barrier system) is demonstrated, in extreme cases, to exceed 100,000 mg/L. The implication is that the system (typically ambient chemical and hydrological conditions) in which radionuclide transport is typically simulated and measured may be significantly different from the perturbed system.

  9. Laboratory And Lysimeter Experimentation And Transport Modeling Of Neptunium And Strontium In Savannah River Site Sediments

    SciTech Connect (OSTI)

    Kaplan, Daniel I.; Powell, B. A.; Miller, Todd J.

    2012-09-24T23:59:59.000Z

    The Savannah River Site (SRS) conducts performance assessment (PA) calculations to determine the appropriate amount of low-level radiological waste that can be safely disposed on site. Parameters are included in these calculations that account for the interaction between the immobile solid phase and the mobile aqueous phase. These parameters are either the distribution coefficient (K{sub d} value) or the apparent solubility value (K{sub sp}). These parameters are readily found in the literature and are used throughout the DOE complex. One shortcoming of K{sub d} values is that they are only applicable to a given set of solid and aqueous phase conditions. Therefore, a given radionuclide may have several K{sub d} values as it moves between formations and comes into contact with different solids and different aqueous phases. It is expected that the K{sub d} construct will be appropriate to use for a majority of the PA and for a majority of the radionuclides. However, semi-mechanistic models would be more representative in isolated cases where the chemistry is especially transitory or the radionuclide chemistry is especially complex, bringing to bear multiple species of varying sorption tendencies to the sediment. Semi-mechanistic models explicitly accommodate the dependency of K{sub d} values, or other sorption parameters, on contaminant concentration, competing ion concentrations, pH-dependent surface charge on the adsorbent, and solute species distribution. Incorporating semi-mechanistic concepts into geochemical models is desirable to make the models more robust and technically defensible. Furthermore, these alternative models could be used to augment or validate a Kd?based DOE Order 435.1 Performance Assessment. The objectives of this study were to: 1) develop a quantitative thermodynamically-based model for neptunium sorption to SRS sediments, and 2) determine a sorption constant from an SRS 11-year lysimeter study. The modeling studies were conducted with existing data sets. The first data set used laboratory generated Np sorption data as a function of concentration (three orders of magnitude) and as a function of pH (four orders of magnitude of proton concentration). In this modeling exercise, a very simple solution was identified by assuming that all sorption occurred only to the iron oxides in the sediment and that all the added NpO{sub 4}{sup -} remained in the oxidized state and was not reduced to the Np(IV) state (as occurs rapidly with Pu(V)). With rather limited input data, very good agreement between experimental and modeling results was observed. This modeling approach would be easy to add to the PA with little additional data requirements. This model would be useful in a system where pH is expected to change greatly, such as directly beneath a grout or concrete structure. The second model discussed in the report was to derive strontium K{sub d} values from data collected in an 11-year-old field transport study. In this controlled lysimeter study, a sensitivity analysis was conducted of hydrological and chemical processes that influence contaminant transport, including diffusion coefficients, seepage velocity, and K{sub d} value. The best overall K{sub d} derived from the model fit to the data was 32 L kg{sup -1}, which was the same value that was previously measured in traditional laboratory batch sorption studies. This was an unexpected result given the differences in experimental conditions between the batch test and the lysimeter flow through test, in particular the differences between strontium adsorption and desorption processes occurring in the latter test and not in the former. There were some trends in the lysimeter strontium data that were not predicted by the K{sub d} model, which suggest that other geochemical processes are likely also controlling strontium transport. Strontium release and cation exchange are being evaluated. These results suggest that future modeling efforts (e.g., PAs) could be improved by employing a more robust semi-empirical modeling approach to transient or complex conditio

  10. Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 99: Rainier Mesa/Shoshone Mountain, Nevada Test Site, Nye County, Nevada, Revision 1

    SciTech Connect (OSTI)

    Nathan Bryant

    2008-05-01T23:59:59.000Z

    This document presents a summary and framework of available transport data and other information directly relevant to the development of the Rainier Mesa/Shoshone Mountain (RMSM) Corrective Action Unit (CAU) 99 groundwater transport model. Where appropriate, data and information documented elsewhere are briefly summarized with reference to the complete documentation.

  11. Power Factor Reactive Power

    E-Print Network [OSTI]

    motor power: 117.7 V x 5.1 A = 600 W? = 0.6 kW? NOT the power measured by meter #12;Page 9 PSERC: displacement power factor: angle between voltage and current = 0 degrees pf = cos(0 degrees) = 1.0 true powerPage 1 PSERC Power Factor and Reactive Power Ward Jewell Wichita State University Power Systems

  12. Reactive power compensating system

    DOE Patents [OSTI]

    Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

    1987-01-01T23:59:59.000Z

    The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

  13. Reactive Power Compensating System.

    DOE Patents [OSTI]

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1985-01-04T23:59:59.000Z

    The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

  14. Chemically Reactive Working Fluids

    Broader source: Energy.gov (indexed) [DOE]

    Capture and Transport of Concentrated Solar Thermal Energy for Power Generation Argonne National Laboratory Award Number: CPS25657 | April 15, 2013 | Brotzman * Thermodynamic and...

  15. Computer Modeling of Transport of Oxidizing Species in Grain Boundaries during Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2014-06-01T23:59:59.000Z

    Zirconium (Zr) based alloys are widely used as the cladding materials in light-water reactors. The water-side corrosion of these alloys degrades their structural integrity and poses serious safety concerns. During the Zr corrosion process, a thin Zr oxide (ZrO2) layer forms on the alloy surface and serves as a barrier layer for further corrosion. The majority of the oxide has the monoclinic phase. At the transition region between the oxide and the metal, the oxide contains a thin layer of stabilized tetragonal phase. It is found that the texture of the tetragonal layer determines the protectiveness of the oxide for corrosion. The transport of oxidizing species, such as anion defects, cation defects, and electron through the tetragonal oxide layer could be the rate limiting step of the corrosion. The defect diffusion can be affected by the growing stresses and microstructures such as grain boundaries and dislocations. In this work molecular dynamics simulations are used to investigate the anion and cation diffusion in bulk and at grain boundaries in tetragonal ZrO2. The results show that defect diffusion at grain boundaries is complex and the behavior strongly depends on the grain boundary type. For most of the grain boundaries studied the defect diffusion are much slower than in the bulk, implying that grain boundaries may not be fast defect transport paths during corrosion. The connection between the modeling results and published experimental work will also be discussed. This work is funded by the Laboratory Directed Research and Development (LDRD) program at Idaho National Laboratory.

  16. The International Symposium on Transportation and Traffic Theory 00 (2013) 119 Linear-Quadratic Model Predictive Control

    E-Print Network [OSTI]

    Nazarathy, Yoni

    2013-01-01T23:59:59.000Z

    al., 1996). The more recent works on traffic control systems have adopted results of modern control responsibility of Delft University of Technology Keywords: Model Predictive Control, Intelligent Transport System, Congestion Control 1. Introduction Increasing population and economic activities in modern societies have led

  17. Canadian Coastal Conference 1999 Conference Canadian sur la littoral 1999 SUSPENDED SEDlMENT TRANSPORT MODELING IN LAKE MICHIGAN

    E-Print Network [OSTI]

    MENT TRANSPORT MODELING IN LAKE MICHIGAN IJ. Lou, ID.J. Schwab, and 2D. Beletsky INOAAlGreat Lakes Environmental and Marine Engineering, University of Michigan~ Cooperative Institute for Limnology and Ecosystems ResearchfNOAA Great Lakes Environmental Research Laboratory and University of Michigan, 2205 Commonwealth Blvd., Ann

  18. GROUNDWATER FLOW AND TRANSPORT MODELING Application to Submarine Groundwater Discharge, Coastal Wetland Hydrology, and Deep Well Injection

    E-Print Network [OSTI]

    Sukop, Mike

    GROUNDWATER FLOW AND TRANSPORT MODELING Application to Submarine Groundwater Discharge, Coastal, but is also lost to surface water drainage and potential submarine groundwater discharge. There are also to deal with issues such as submarine groundwater discharge and coastal wetland hydrology. SEAWAT also has

  19. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Converse, Alexander K.; Ahlers, Elizabeth O.; Bryan, Tom W.; Hetue, Jackson D.; Lake, Katherine A.; Ellison, Paul A.; Engle, Jonathan W.; Barnhart, Todd E.; Nickles, Robert J.; Williams, Paul H.; et al

    2015-01-01T23:59:59.000Z

    Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [¹?F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modelingmore »of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [¹?F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.« less

  20. Fluctuation level bursts in a model of internal transport barrier formation D. Lopez-Bruna, D. E. Newman, and B. A. Carreras

    E-Print Network [OSTI]

    Newman, David

    features of ITB models the phase transition character with a power threshold, barrier front propagation radial electric field.10,11 As happens with the edge transport barriers, the system reacts to the extraFluctuation level bursts in a model of internal transport barrier formation D. Lo´pez-Bruna, D. E

  1. Heavy Duty Diesel Particulate Matter and Fuel Consumption Modeling for Transportation Analysis

    E-Print Network [OSTI]

    Scora, George Alexander

    2011-01-01T23:59:59.000Z

    Duty Vehicle and Truck Emissions. Transportation Researchin on-highway truck emission certification standards in theclass (e.g. , car, truck), emission technology (e.g. , no

  2. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 10, NO. 1, JANUARY/FEBRUARY 2004 37 Monte Carlo Modeling of the Light Transport in

    E-Print Network [OSTI]

    Kanicki, Jerzy

    absorption, thin-film coatings, and uneven or irregular surfaces by tracking the photon polarization aerogel layer [10]. Several models have also been proposed for modeling optical transport in organic light

  3. Comparison of Average Transport and Dispersion Among a Gaussian Model, a Two-Dimensional Model and a Three-Dimensional Model

    SciTech Connect (OSTI)

    Mitchell, J A; Molenkamp, C R; Bixler, N E; Morrow, C W; Ramsdell, Jr., J V

    2004-05-10T23:59:59.000Z

    The Nuclear Regulatory Commission uses MACCS2 (MELCOR Accident Consequence Code System, Version 2) for regulatory purposes such as planning for emergencies and cost-benefit analyses. MACCS2 uses a straight-line Gaussian model for atmospheric transport and dispersion. This model has been criticized as being overly simplistic, although only expected values of metrics of interest are used in the regulatory arena. To test the assumption that averaging numerous weather results adequately compensates for the loss of structure in the meteorology that occurs away from the point of release, average MACCS2 results have been compared with average results from a state-of-the-art, 3-dimensional LODI (Lagrangian Operational Dispersion Integrator)/ADAPT (Atmospheric Data Assimilation and Parameterization Technique) and a Lagrangian trajectory, Gaussian puff transport and dispersion model from RASCAL (Radiological Assessment System for consequence Analysis). The weather sample included 610 weather trials representing conditions for a hypothetical release at the Central Facility of the Department of Energy's Atmospheric Radiation Measurement site. The values compared were average ground concentrations and average surface-level air concentrations at several distances out to 100 miles (160.9 km) from the assumed release site.

  4. Reactive Air Aluminization

    SciTech Connect (OSTI)

    Choi, Jung-Pyung; Chou, Y. S.; Stevenson, Jeffry W.

    2011-10-28T23:59:59.000Z

    Ferritic stainless steels and other alloys are of great interest to SOFC developers for applications such as interconnects, cell frames, and balance of plant components. While these alloys offer significant advantages (e.g., low material and manufacturing cost, high thermal conductivity, and high temperature oxidation resistance), there are challenges which can hinder their utilization in SOFC systems; these challenges include Cr volatility and reactivity with glass seals. To overcome these challenges, protective coatings and surface treatments for the alloys are under development. In particular, aluminization of alloy surfaces offers the potential for mitigating both evaporation of Cr from the alloy surface and reaction of alloy constituents with glass seals. Commercial aluminization processes are available to SOFC developers, but they tend to be costly due to their use of exotic raw materials and/or processing conditions. As an alternative, PNNL has developed Reactive Air Aluminization (RAA), which offers a low-cost, simpler alternative to conventional aluminization methods.

  5. Vehicle Technologies Office Merit Review 2015: Transportation Energy Transition Modeling and Analysis: the LAVE-Trans Model

    Broader source: Energy.gov [DOE]

    Presentation given by Oak Ridge National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about transportation...

  6. ORNL/TM-2008/083 A Tariff for Reactive Power

    E-Print Network [OSTI]

    Pennycook, Steve

    ORNL/TM-2008/083 A Tariff for Reactive Power 2008 Prepared by Christopher Tufon, Pacific Gas & Electric Company Alan G. Isemonger, California Independent System Operator Brendan Kirby, ORNL, Knowledge and Transportation Science Division A Tariff for Reactive Power Christopher Tufon Alan G. Isemonger Brendan Kirby

  7. Vadose Zone Transport Field Study: Summary Report

    SciTech Connect (OSTI)

    Ward, Andy L.; Conrad, Mark E.; Daily, William D.; Fink, James B.; Freedman, Vicky L.; Gee, Glendon W.; Hoversten, Gary M.; Keller, Jason M.; Majer, Ernest L.; Murray, Christopher J.; White, Mark D.; Yabusaki, Steven B.; Zhang, Z. F.

    2006-07-31T23:59:59.000Z

    From FY 2000 through FY 2003, a series of vadose zone transport field experiments were conducted as part of the U.S. Department of Energy’s Groundwater/Vadose Zone Integration Project Science and Technology Project, now known as the Remediation and Closure Science Project, and managed by the Pacific Northwest National Laboratory (PNNL). The series of experiments included two major field campaigns, one at a 299-E24-11 injection test site near PUREX and a second at a clastic dike site off Army Loop Road. The goals of these experiments were to improve our understanding of vadose zone transport processes; to develop data sets to validate and calibrate vadose zone flow and transport models; and to identify advanced monitoring techniques useful for evaluating flow-and-transport mechanisms and delineating contaminant plumes in the vadose zone at the Hanford Site. This report summarizes the key findings from the field studies and demonstrates how data collected from these studies are being used to improve conceptual models and develop numerical models of flow and transport in Hanford’s vadose zone. Results of these tests have led to a better understanding of the vadose zone. Fine-scale geologic heterogeneities, including grain fabric and lamination, were observed to have a strong effect on the large-scale behavior of contaminant plumes, primarily through increased lateral spreading resulting from anisotropy. Conceptual models have been updated to include lateral spreading and numerical models of unsaturated flow and transport have revised accordingly. A new robust model based on the concept of a connectivity tensor was developed to describe saturation-dependent anisotropy in strongly heterogeneous soils and has been incorporated into PNNL’s Subsurface Transport Over Multiple Phases (STOMP) simulator. Application to field-scale transport problems have led to a better understanding plume behavior at a number of sites where lateral spreading may have dominated waste migration (e.g. BC Cribs and Trenches). The improved models have been also coupled with inverse models and newly-developed parameter scaling techniques to allow estimation of field-scale and effective transport parameters for the vadose zone. The development and utility of pedotransfer functions for describing fine-scale hydrogeochemical heterogeneity and for incorporating this heterogeneity into reactive transport models was explored. An approach based on grain-size statistics appears feasible and has been used to describe heterogeneity in hydraulic properties and sorption properties, such as the cation exchange capacity and the specific surface area of Hanford sediments. This work has also led to the development of inverse modeling capabilities for time-dependent, subsurface, reactive transport with transient flow fields using an automated optimization algorithm. In addition, a number of geophysical techniques investigated for their potential to provide detailed information on the subtle changes in lithology and bedding surfaces; plume delineation, leak detection. High-resolution resistivity is now being used for detecting saline plumes at several waste sites at Hanford, including tank farms. Results from the field studies and associated analysis have appeared in more than 46 publications generated over the past 4 years. These publications include test plans and status reports, in addition to numerous technical notes and peer reviewed papers.

  8. Bedload Transport. Part 1: Two-Phase Model and 3D Numerical Implementation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    by Ouriemi et al. (2009a) to study bedload transport in pipe flows. The governing equations are discretized flows with the hydrate or sand issues in oil production and granular transport in food or pharmaceutical the fluid-particle interaction is assumed to follow a Darcy law. This approach allows to predict

  9. A sediment transport model for incision of gullies on steep Erkan Istanbulluoglu,1

    E-Print Network [OSTI]

    Tarboton, David

    higher than those for bed load transport in alluvial rivers but is in the range of shear stress exponents derived from flume experiments on steep slopes and with total load equations. The concavity index of the gully profiles obtained theoretically from the area and slope exponents of the sediment transport

  10. Transport Model Linear Evaluation Parametric Scan: limit of Te,i = 0

    E-Print Network [OSTI]

    Hammett, Greg

    , G. W. Hammett Princeton Plasma Physics Laboratory, Princeton, NJ 2011 U.S. Transport Task Force]. In addition, the outward heat flux is less than the convective heat flux, due to preferential transport of low-ion coupling suppress the edge Ti resulting in a steep ion temperature gradient and low Ti /Te which drive

  11. RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation

    SciTech Connect (OSTI)

    Humphreys, S.L.; Miller, L.A.; Monroe, D.K. [Sandia National Labs., Albuquerque, NM (United States); Heames, T.J. [ITSC, Albuquerque, NM (United States)

    1998-04-01T23:59:59.000Z

    This report documents the RADTRAD computer code developed for the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) to estimate transport and removal of radionuclides and dose at selected receptors. The document includes a users` guide to the code, a description of the technical basis for the code, the quality assurance and code acceptance testing documentation, and a programmers` guide. The RADTRAD code can be used to estimate the containment release using either the NRC TID-14844 or NUREG-1465 source terms and assumptions, or a user-specified table. In addition, the code can account for a reduction in the quantity of radioactive material due to containment sprays, natural deposition, filters, and other natural and engineered safety features. The RADTRAD code uses a combination of tables and/or numerical models of source term reduction phenomena to determine the time-dependent dose at user-specified locations for a given accident scenario. The code system also provides the inventory, decay chain, and dose conversion factor tables needed for the dose calculation. The RADTRAD code can be used to assess occupational radiation exposures, typically in the control room; to estimate site boundary doses; and to estimate dose attenuation due to modification of a facility or accident sequence.

  12. Phase I Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nye County, Nevada, Revision 0

    SciTech Connect (OSTI)

    John McCord

    2007-09-01T23:59:59.000Z

    This report documents transport data and data analyses for Yucca Flat/Climax Mine CAU 97. The purpose of the data compilation and related analyses is to provide the primary reference to support parameterization of the Yucca Flat/Climax Mine CAU transport model. Specific task objectives were as follows: • Identify and compile currently available transport parameter data and supporting information that may be relevant to the Yucca Flat/Climax Mine CAU. • Assess the level of quality of the data and associated documentation. • Analyze the data to derive expected values and estimates of the associated uncertainty and variability. The scope of this document includes the compilation and assessment of data and information relevant to transport parameters for the Yucca Flat/Climax Mine CAU subsurface within the context of unclassified source-term contamination. Data types of interest include mineralogy, aqueous chemistry, matrix and effective porosity, dispersivity, matrix diffusion, matrix and fracture sorption, and colloid-facilitated transport parameters.

  13. A Validation Process for the Groundwater Flow and Transport Model of the Faultless Nuclear Test at Central Nevada Test Area

    SciTech Connect (OSTI)

    Ahmed Hassan

    2003-01-01T23:59:59.000Z

    Many sites of groundwater contamination rely heavily on complex numerical models of flow and transport to develop closure plans. This has created a need for tools and approaches that can be used to build confidence in model predictions and make it apparent to regulators, policy makers, and the public that these models are sufficient for decision making. This confidence building is a long-term iterative process and it is this process that should be termed ''model validation.'' Model validation is a process not an end result. That is, the process of model validation cannot always assure acceptable prediction or quality of the model. Rather, it provides safeguard against faulty models or inadequately developed and tested models. Therefore, development of a systematic approach for evaluating and validating subsurface predictive models and guiding field activities for data collection and long-term monitoring is strongly needed. This report presents a review of model validation studies that pertain to groundwater flow and transport modeling. Definitions, literature debates, previously proposed validation strategies, and conferences and symposia that focused on subsurface model validation are reviewed and discussed. The review is general in nature, but the focus of the discussion is on site-specific, predictive groundwater models that are used for making decisions regarding remediation activities and site closure. An attempt is made to compile most of the published studies on groundwater model validation and assemble what has been proposed or used for validating subsurface models. The aim is to provide a reasonable starting point to aid the development of the validation plan for the groundwater flow and transport model of the Faultless nuclear test conducted at the Central Nevada Test Area (CNTA). The review of previous studies on model validation shows that there does not exist a set of specific procedures and tests that can be easily adapted and applied to determine the validity of site-specific groundwater models. This is true for both deterministic and stochastic models, with the latter posing a more difficult and challenging problem when it comes to validation. This report then proposes a general validation approach for the CNTA model, which addresses some of the important issues recognized in previous validation studies, conferences, and symposia as crucial to the process. The proposed approach links model building, model calibration, model predictions, data collection, model evaluations, and model validation in an iterative loop. The approach focuses on use of collected validation data to reduce model uncertainty and narrow the range of possible outcomes of stochastic numerical models. It accounts for the stochastic nature of the numerical CNTA model, which used Monte Carlo simulation approach. The proposed methodology relies on the premise that absolute validity is not even a theoretical possibility and is not a regulatory requirement. Rather, it highlights the importance of testing as many aspects of the model as possible and using as many diverse statistical tools as possible for rigorous checking and confidence building in the model and its predictions. It is this confidence that will eventually allow for regulator and public acceptance of decisions based on the model predictions.

  14. Reactive transport modeling to study changes in water chemistry induced by CO2 injection at the Frio-I brine pilot

    E-Print Network [OSTI]

    Kharaka, Y.K

    2010-01-01T23:59:59.000Z

    using the same kinetic expression as that for dissolution.Kinetic rate law for mineral dissolution and precipitation The general rate expression

  15. Identifying key controls on the behavior of an acidic-U(VI) plume in the Savannah River Site using reactive transport modeling

    E-Print Network [OSTI]

    Hubbard, Susan

    National Lab., 1 Cyclotron Road Mail Stop 90R1116, Berkeley, CA 94720-8126, United States b Savannah RiverIdentifying key controls on the behavior of an acidic-U(VI) plume in the Savannah River Site using National Lab., Bldg. 773-42A, Aiken, SC 29808, United States a r t i c l e i n f o a b s t r a c t Article

  16. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    E-Print Network [OSTI]

    Birkle, P.

    2009-01-01T23:59:59.000Z

    development in Mexico,” Oilfield Review (Spring 2004) 48. 3.Poza Rica – Altamira oilfield forms part of the Chicontepecthe Poza Rica – Altamira oilfield, a total of 16,060 BPD (

  17. Dynamics of P-binding forms in sediments of a mesotrophic hard-water lake: Insights from non-steady state reactive-transport modeling,

    E-Print Network [OSTI]

    Arhonditsis, George B.

    Gudimov 1 , George Arhonditsis, Alexey Chesnyuk, Maria Dittrich Department of Physical and Environmental r t i c l e i n f o Article history: Received 6 November 2012 Received in revised form 10 June 2013 the fractionation data of phosphorus binding forms. The impact of the interplay between sedi- mentation fluxes

  18. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    E-Print Network [OSTI]

    Birkle, P.

    2009-01-01T23:59:59.000Z

    1. Williams, P. : “Mexico,” Oil and Gas Investor (July 2003)oil field, bordering the Gulf coast in the eastern part of Mexico,

  19. Reactive transport modeling to study changes in water chemistry induced by CO2 injection at the Frio-I brine pilot

    E-Print Network [OSTI]

    Kharaka, Y.K

    2010-01-01T23:59:59.000Z

    L. , Hua, W. , 2009. Petrology and isotopic geochemistry ofrock systems with varying petrology. For regular grids, the

  20. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    E-Print Network [OSTI]

    Birkle, P.

    2009-01-01T23:59:59.000Z

    11 to 48 m 3 /d]. Recently, PEMEX initiated an aggressiveand Petróleos Mexicanos (PEMEX, Subdirección Region Norte),oilfield. Thanks to the PEMEX administration for the

  1. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    E-Print Network [OSTI]

    Birkle, P.

    2009-01-01T23:59:59.000Z

    Waterflooding for enhanced oil recovery requires thatas part of an enhanced oil recovery program. U S A Mpart the scheduled enhanced oil recovery project at the Poza

  2. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    E-Print Network [OSTI]

    Birkle, P.

    2009-01-01T23:59:59.000Z

    into the Agua Fría reservoir, data from laboratory flowChemical analytical data from reservoir water were appliedapplied as input data for initial reservoir conditions. In

  3. Use of principal components analysis and three-dimensional atmospheric-transport models for reactor-consequence evaluation

    SciTech Connect (OSTI)

    Gudiksen, P.H.; Walton, J.J.; Alpert, D.J.; Johnson, J.D.

    1982-01-01T23:59:59.000Z

    This work explores the use of principal components analysis coupled to three-dimensional atmospheric transport and dispersion models for evaluating the environmental consequences of reactor accidents. This permits the inclusion of meteorological data from multiple sites and the effects of topography in the consequence evaluation; features not normally included in such analyses. The technique identifies prevailing regional wind patterns and their frequencies for use in the transport and dispersion calculations. Analysis of a hypothetical accident scenario involving a release of radioactivity from a reactor situated in a river valley indicated the technique is quite useful whenever recurring wind patterns exist, as is often the case in complex terrain situations. Considerable differences were revealed in a comparison with results obtained from a more conventional Gaussian plume model using only the reactor site meteorology and no topographic effects.

  4. The Evaluation of Transportation and Land Use Plans Using Linked Economic and GIS Models

    E-Print Network [OSTI]

    Johnston, Robert A.

    1995-01-01T23:59:59.000Z

    Attempts to base the economic evaluation travel no state isurban economyand and economic evaluations. for devlsing andEvaluation of Transportation and Land Use Plans Using Linked Economic and

  5. Modeling the Transport Sector: The Role of Existing Fuel Taxes in Climate Policy

    E-Print Network [OSTI]

    Paltsev, Sergey.

    Existing fuel taxes play a major role in determining the welfare effects of exempting the transportation sector from measures to control greenhouse gases. To study this phenomenon we modify the MIT Emissions Prediction and ...

  6. Computations and modeling of oil transport between piston lands and liner in internal combustion engines

    E-Print Network [OSTI]

    Fang, Tianshi

    2014-01-01T23:59:59.000Z

    The consumption of lubricating oil in internal combustion engines is a continuous interest for engine developers and remains to be one of the least understood areas. A better understanding on oil transport is critical to ...

  7. Transportation Secure Data Center: Real-World Data for Planning, Modeling and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01T23:59:59.000Z

    The National Renewable Energy Laboratory (NREL) and the U.S. Department of Transportation (DOT) have launched the free, web-based Transportation Secure Data Center (TSDC). The TSDC (www.nrel.gov/tsdc) preserves respondent anonymity while making vital transportation data available to a broad group of users through secure, online access. The TSDC database gives, metropolitan planning organizations, universities, national laboratories, air quality management districts, disaster planning agencies and auto manufacturers free-of-charge web-based access to valuable transportation data. The TSDC's two levels of access make composite data available with simple online registration, and allow researchers to use detailed spatial data after completing a straight forward application process.

  8. Pore-scale modeling of electrical and fluid transport in Berea sandstone

    E-Print Network [OSTI]

    Zhan, Xin

    The purpose of this paper is to test how well numerical calculations can predict transport properties of porous permeable rock, given its 3D digital microtomography (?CT) image. For this study, a Berea 500 sandstone sample ...

  9. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    E-Print Network [OSTI]

    Danko, G.

    2010-01-01T23:59:59.000Z

    stages after waste emplacement, the coupled, in-drift heat,waste emplacement, forced ventilation removes the majority of the heatheat and moisture transport processes. domain includes the waste

  10. Transportation Secure Data Center: Real-World Data for Planning, Modeling, and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-01-01T23:59:59.000Z

    This fact sheet describes the Transportation Secure Data Center (TSDC) - an NREL-operated resource that provides secure access to detailed GPS travel data for valuable research purposes in a way that protects original participant privacy.

  11. Three-dimensional Modeling of Acid Transport and Etching in a Fracture 

    E-Print Network [OSTI]

    Oeth, Cassandra V

    2013-11-25T23:59:59.000Z

    -dimensional acid transport and reaction within a fracture to yield the etched width created by acid along the fracture. The conductivity is calculated with the simulator derived acid-etched width, using correlations recently developed that reflect the small scale...

  12. Reaction plane angle dependence of dihadron azimuthal correlations from a multiphase transport model calculation

    E-Print Network [OSTI]

    W. Li; S. Zhang; Y. G. Ma; X. Z. Cai; J. H. Chen; H. Z. Huang; G. L. Ma; C. Zhong

    2010-01-07T23:59:59.000Z

    Dihadron azimuthal angle correlations relative to the reaction plane have been investigated in Au + Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV using a multi-phase transport model (AMPT). Such reaction plane azimuthal angle dependent correlations can shed light on path-length effect of energy loss of high transverse momentum particles propagating through the hot dense medium. The correlations vary with the trigger particle azimuthal angle with respect to the reaction plane direction, $\\phi_{s}=\\phi_{T}-\\Psi_{EP}$, which is consistent with the experimental observation by the STAR collaboration. The dihadron azimuthal angle correlation functions on the away side of the trigger particle present a distinct evolution from a single peak to a broad, possibly double peak, structure when the trigger particle direction goes from in-plane to out-of-plane of the reaction plane. The away-side angular correlation functions are asymmetric with respect to the back-to-back direction in some regions of $\\phi_{s}$, which could provide insight on testing $v_{1}$ method to reconstruct the reaction plane. In addition, both the root-mean-square width ($W_{rms}$) of the away-side correlation distribution and the splitting parameter $D$ between the away-side double peaks increase slightly with $\\phi_{s}$, and the average transverse momentum of the away-side associated hadrons shows a strong $\\phi_{s}$ dependence. Our results indicate that strong parton cascade and resultant energy loss could play an important role for the appearance of a double-peak structure in the dihadron azimuthal angular correlation function on the away side of the trigger particle.

  13. Phase II Transport Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Revision 1

    SciTech Connect (OSTI)

    Gregg Ruskuaff

    2010-01-01T23:59:59.000Z

    This document, the Phase II Frenchman Flat transport report, presents the results of radionuclide transport simulations that incorporate groundwater radionuclide transport model statistical and structural uncertainty, and lead to forecasts of the contaminant boundary (CB) for a set of representative models from an ensemble of possible models. This work, as described in the Federal Facility Agreement and Consent Order (FFACO) Underground Test Area (UGTA) strategy (FFACO, 1996; amended 2010), forms an essential part of the technical basis for subsequent negotiation of the compliance boundary of the Frenchman Flat corrective action unit (CAU) by Nevada Division of Environmental Protection (NDEP) and National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Underground nuclear testing via deep vertical shafts was conducted at the Nevada Test Site (NTS) from 1951 until 1992. The Frenchman Flat area, the subject of this report, was used for seven years, with 10 underground nuclear tests being conducted. The U.S. Department of Energy (DOE), NNSA/NSO initiated the UGTA Project to assess and evaluate the effects of underground nuclear tests on groundwater at the NTS and vicinity through the FFACO (1996, amended 2010). The processes that will be used to complete UGTA corrective actions are described in the “Corrective Action Strategy” in the FFACO Appendix VI, Revision No. 2 (February 20, 2008).

  14. CLEAR (Calculates Logical Evacuation And Response): A Generic Transportation Network Model for the Calculation of Evacuation Time Estimates

    SciTech Connect (OSTI)

    Moeller, M. P.; Urbanik, II, T.; Desrosiers, A. E.

    1982-03-01T23:59:59.000Z

    This paper describes the methodology and application of the computer model CLEAR (Calculates Logical Evacuation And Response) which estimates the time required for a specific population density and distribution to evacuate an area using a specific transportation network. The CLEAR model simulates vehicle departure and movement on a transportation network according to the conditions and consequences of traffic flow. These include handling vehicles at intersecting road segments, calculating the velocity of travel on a road segment as a function of its vehicle density, and accounting for the delay of vehicles in traffic queues. The program also models the distribution of times required by individuals to prepare for an evacuation. In order to test its accuracy, the CLEAR model was used to estimate evacuatlon tlmes for the emergency planning zone surrounding the Beaver Valley Nuclear Power Plant. The Beaver Valley site was selected because evacuation time estimates had previously been prepared by the licensee, Duquesne Light, as well as by the Federal Emergency Management Agency and the Pennsylvania Emergency Management Agency. A lack of documentation prevented a detailed comparison of the estimates based on the CLEAR model and those obtained by Duquesne Light. However, the CLEAR model results compared favorably with the estimates prepared by the other two agencies.

  15. ENVIRONMENTAL REACTIVITY OF SOLID STATE HYDRIDE MATERIALS

    SciTech Connect (OSTI)

    Gray, J; Donald Anton, D

    2009-04-23T23:59:59.000Z

    In searching for high gravimetric and volumetric density hydrogen storage systems, it is inevitable that higher energy density materials will be used. In order to make safe and commercially acceptable condensed phase hydrogen storage systems, it is important to understand quantitatively the risks involved in using and handling these materials and to develop appropriate mitigation strategies to handle potential material exposure events. A crucial aspect of the development of risk identification and mitigation strategies is the development of rigorous environmental reactivity testing standards and procedures. This will allow for the identification of potential risks and implementation of risk mitigation strategies. Modified testing procedures for shipping air and/or water sensitive materials, as codified by the United Nations, have been used to evaluate two potential hydrogen storage materials, 2LiBH{sub 4} {center_dot} MgH{sub 2} and NH{sub 3}BH{sub 3}. The modified U.N. procedures include identification of self-reactive substances, pyrophoric substances, and gas-emitting substances with water contact. The results of these tests for air and water contact sensitivity will be compared to the pure material components where appropriate (e.g. LiBH{sub 4} and MgH{sub 2}). The water contact tests are divided into two scenarios dependent on the hydride to water mole ratio and heat transport characteristics. Air contact tests were run to determine whether a substance will spontaneously react with air in a packed or dispersed form. In the case of the 2LiBH{sub 4} {center_dot} MgH{sub 2} material, the results from the hydride mixture compared to the pure materials results showed the MgH{sub 2} to be the least reactive component and LiBH{sub 4} the more reactive. The combined 2LiBH{sub 4} {center_dot} MgH{sub 2} resulted in a material having environmental reactivity between these two materials. Relative to 2LiBH{sub 4} {center_dot} MgH{sub 2}, the chemical hydride NH{sub 3}BH{sub 3} was observed to be less environmentally reactive.

  16. Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. II. Inclusion of Radiative Transfer with RADYN

    E-Print Network [OSTI]

    da Costa, Fatima Rubio; Petrosian, Vahe'; Carlsson, Mats

    2015-01-01T23:59:59.000Z

    Solar flares involve complex processes that are coupled together and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present such a model to simulate the coupling of high-energy particle kinetics with hydrodynamics of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration, transport, and bremsstrahlung radiation with the RADYN hydrodynamic code that models the atmospheric response to collisional heating by non-thermal electrons through detailed radiative transfer calculations. We perform simulations using different injection electron spectra, including an {\\it ad hoc} power law and more realistic spectra predicted by the stochastic acceleration model due to turbulence or plasma waves. Surprisingly, stochastically accelerated electrons, even with energy flux $\\ll 10^{10}$ erg s$^{-1}$ cm$^{-2}$, cause "explosive" chromospheric evaporation and drive stronger up- an...

  17. Predictive Modeling of Transient Storage and Nutrient Uptake: Implications for Stream Restoration

    E-Print Network [OSTI]

    Predictive Modeling of Transient Storage and Nutrient Uptake: Implications for Stream Restoration of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling geomorphology and hydraulics influence nu- trient uptake is vital for stream restoration projects that modify

  18. Regional groundwater flow and tritium transport modeling and risk assessment of the underground test area, Nevada Test Site, Nevada

    SciTech Connect (OSTI)

    None

    1997-10-01T23:59:59.000Z

    The groundwater flow system of the Nevada Test Site and surrounding region was evaluated to estimate the highest potential current and near-term risk to the public and the environment from groundwater contamination downgradient of the underground nuclear testing areas. The highest, or greatest, potential risk is estimated by assuming that several unusually rapid transport pathways as well as public and environmental exposures all occur simultaneously. These conservative assumptions may cause risks to be significantly overestimated. However, such a deliberate, conservative approach ensures that public health and environmental risks are not underestimated and allows prioritization of future work to minimize potential risks. Historical underground nuclear testing activities, particularly detonations near or below the water table, have contaminated groundwater near testing locations with radioactive and nonradioactive constituents. Tritium was selected as the contaminant of primary concern for this phase of the project because it is abundant, highly mobile, and represents the most significant contributor to the potential radiation dose to humans for the short term. It was also assumed that the predicted risk to human health and the environment from tritium exposure would reasonably represent the risk from other, less mobile radionuclides within the same time frame. Other contaminants will be investigated at a later date. Existing and newly collected hydrogeologic data were compiled for a large area of southern Nevada and California, encompassing the Nevada Test Site regional groundwater flow system. These data were used to develop numerical groundwater flow and tritium transport models for use in the prediction of tritium concentrations at hypothetical human and ecological receptor locations for a 200-year time frame. A numerical, steady-state regional groundwater flow model was developed to serve as the basis for the prediction of the movement of tritium from the underground testing areas on a regional scale. The groundwater flow model was used in conjunction with a particle-tracking code to define the pathlines followed by groundwater particles originating from 415 points associated with 253 nuclear test locations. Three of the most rapid pathlines were selected for transport simulations. These pathlines are associated with three nuclear test locations, each representing one of the three largest testing areas. These testing locations are: BOURBON on Yucca Flat, HOUSTON on Central Pahute Mesa, and TYBO on Western Pahute Mesa. One-dimensional stochastic tritium transport simulations were performed for the three pathlines using the Monte Carlo method with Latin hypercube sampling. For the BOURBON and TYBO pathlines, sources of tritium from other tests located along the same pathline were included in the simulations. Sensitivity analyses were also performed on the transport model to evaluate the uncertainties associated with the geologic model, the rates of groundwater flow, the tritium source, and the transport parameters. Tritium concentration predictions were found to be mostly sensitive to the regional geology in controlling the horizontal and vertical position of transport pathways. The simulated concentrations are also sensitive to matrix diffusion, an important mechanism governing the migration of tritium in fractured carbonate and volcanic rocks. Source term concentration uncertainty is most important near the test locations and decreases in importance as the travel distance increases. The uncertainty on groundwater flow rates is as important as that on matrix diffusion at downgradient locations. The risk assessment was performed to provide conservative and bounding estimates of the potential risks to human health and the environment from tritium in groundwater. Risk models were designed by coupling scenario-specific tritium intake with tritium dose models and cancer and genetic risk estimates using the Monte Carlo method. Estimated radiation doses received by individuals from chronic exposure to tritium, and the corre

  19. Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake Michigan.

    SciTech Connect (OSTI)

    Lee, C.; Schwab, D. J.; Beletsky, D.; Stroud, J.; Lesht, B.; PNNL; NOAA; Univ. of Michigan; Univ. of Pennsylvania

    2007-02-17T23:59:59.000Z

    A two-dimensional sediment transport model capable of simulating sediment resuspension of mixed (cohesive plus noncohesive) sediment is developed and applied to quantitatively simulate the March 1998 resuspension events in southern Lake Michigan. Some characteristics of the model are the capability to incorporate several floc size classes, a physically based settling velocity formula, bed armoring, and sediment availability limitation. Important resuspension parameters were estimated from field and laboratory measurement data. The model reproduced the resuspension plume (observed by the SeaWIFS satellite and field instruments) and recently measured sedimentation rate distribution (using radiotracer techniques) fairly well. Model results were verified with field measurements of suspended sediment concentration and settling flux (by ADCPs and sediment traps). Both wave conditions and sediment bed properties (critical shear stress, fine sediment fraction, and limited sediment availability or source) are the critical factors that determine the concentration distribution and width of the resuspension plume. The modeled sedimentation pattern shows preferential accumulation of sediment on the eastern side of the lake, which agrees with the observed sedimentation pattern despite a predominance of particle sources from the western shoreline. The main physical mechanisms determining the sedimentation pattern are (1) the two counter-rotating circulation gyres producing offshore mass transport along the southeastern coast during northerly wind and (2) the settling velocity of sediment flocs which controls the deposition location.

  20. Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake Michigan

    SciTech Connect (OSTI)

    Lee, Cheegwan; Schwab, David J.; Beletsky, Dmitry; Stroud, Jonathan; Lesht, B. M.

    2007-02-17T23:59:59.000Z

    A two-dimensional sediment transport model capable of simulating sediment resuspension of mixed (cohesive+noncohesive) sediment is developed and applied to quantitatively simulate the March 1998 resuspension events in southern Lake Michigan. Some characteristics of the model are the capability to incorporate several floc size classes, a physically-based settling velocity formula, bed armoring, and sediment availability limitation. Important resuspension parameters were estimated from field and laboratory measurement data. The model reproduced the resuspension plume (observed by the SeaWIFS satellite and field instruments) and recently measured sedimentation rate distribution (using radiotracer techniques) fairly well. Model results were verified with field measurements of suspended sediment concentration and settling flux (by ADCPs and sediment traps). Both wave conditions and sediment bed properties (critical shear stress, fine sediment fraction, and limited sediment availability or source) are the critical factors that determine the concentration distribution and width of the resuspension plume. The modeled sedimentation pattern shows preferential accumulation of sediment on the eastern side of the lake, which agrees with the observed sedimentation pattern despite a predominance of particle sources from the western shoreline. The main physical mechanisms determining the sedimentation pattern are 1) the two counter-rotating circulation gyres producing offshore mass transport along the southeastern coast during northerly wind and 2) the settling velocity of sediment flocs which controls the deposition location.

  1. Evidence of Reactive Aromatics As a Major Source of Peroxy Acetyl Nitrate over China

    SciTech Connect (OSTI)

    Liu, Zhen; Wang, Yuhang; Gu, Dasa; Zhao, Chun; Huey, L. G.; Stickel, Robert; Liao, Jin; Shao, Min; Zhu, T.; Zeng, Limin; Liu, Shaw C.; Chang, Chih-Chung; Amoroso, Antonio; Costabile, Francesa

    2010-09-15T23:59:59.000Z

    We analyze the observations of near-surface peroxy acetyl nitrate (PAN) and its precursors in Beijing, China in August of 2007. The levels of PAN are remarkably high (up to 14 ppbv), surpassing those measured over other urban regions in recent years. Analyses employing a 1-D version of a chemical transport model (Regional chEmical and trAnsport Model, REAM) indicate that aromatic non-methane hydrocarbons (NMHCs) are the dominant (55-75%) PAN source. The major oxidation product of aromatics that produces acetyl peroxy radicals is methylglyoxal (MGLY). PAN and O3 in the observations are correlated at daytime; aromatic NMHCs appear to play an important role in O3 photochemistry. Previous NMHC measurements indicate the presence of reactive aromatics at high levels over broad polluted regions of China. Aromatics are often ignored in global and (to a lesser degree) regional 3D photochemical transport models; their emissions over China as well as photochemistry are quite uncertain.Our findings suggest that critical assessments of aromatics emissions and chemistry (such as the yields of MGLY) are necessary to understand and assess ozone photochemistry and regional pollution export in China.

  2. Inhomogeneous transport in model hydrated polymer electrolyte supported ultra-thin films

    E-Print Network [OSTI]

    D. Damasceno Borges; A. A. Franco; K. Malek; G. Gebel; S. Mossa

    2013-10-02T23:59:59.000Z

    Structure of polymer electrolytes membranes, e.g., Nafion, inside fuel cell catalyst layers has significant impact on the electrochemical activity and transport phenomena that determine cell performance. In those regions, Nafion can be found as an ultra-thin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic/hydrophobic character of these surfaces on the structural formation of the films and, in turn, on transport properties, has not been sufficiently explored yet. Here, we report about classical Molecular Dynamics simulations of hydrated Nafion thin-films in contact with unstructured supports, characterized by their global wetting properties only. We have investigated structure and transport in different regions of the film and found evidences of strongly heterogeneous behavior. We speculate about the implications of our work on experimental and technological activity.

  3. The Development of an Effective Transportation Risk Assessment Model for Analyzing the Transport of Spent Fuel and High-Level Radioactive Waste to the Proposed Yucca Mountain Repository

    SciTech Connect (OSTI)

    McSweeney; Thomas; Winnard; Ross; Steven B.; Best; Ralph E.

    2001-02-06T23:59:59.000Z

    Past approaches for assessing the impacts of transporting spent fuel and high-level radioactive waste have not been effectively implemented or have used relatively simple approaches. The Yucca Mountain Draft Environmental Impact Statement (DEIS) analysis considers 83 origins, 34 fuel types, 49,914 legal weight truck shipments, 10,911 rail shipments, consisting of 59,250 shipment links outside Nevada (shipment kilometers and population density pairs through urban, suburban or rural zones by state), and 22,611 shipment links in Nevada. There was additional complexity within the analysis. The analysis modeled the behavior of 41 isotopes, 1091 source terms, and used 8850 food transfer factors (distinct factors by isotope for each state). The model also considered different accident rates for legal weight truck, rail, and heavy haul truck by state, and barge by waterway. To capture the all of the complexities of the transportation analysis, a Microsoft{reg_sign} Access database was created. In the Microsoft{reg_sign} Access approach the data is placed in individual tables and equations are developed in queries to obtain the overall impacts. While the query might be applied to thousands of table entries, there is only one equation for a particular impact. This greatly simplifies the validation effort. Furthermore, in Access, data in tables can be linked automatically using query joins. Another advantage built into MS Access is nested queries, or the ability to develop query hierarchies. It is possible to separate the calculation into a series of steps, each step represented by a query. For example, the first query might calculate the number of shipment kilometers traveled through urban, rural and suburban zones for all states. Subsequent queries could join the shipment kilometers query results with another table containing the state and mode specific accident rate to produce accidents by state. One of the biggest advantages of the nested queries is in validation. Temporarily restricting the query to one origin, one shipment, or one state and validating that the query calculation is returning the expected result allows simple validation. The paper will show the flexibility of the assessment tool to consider a wide variety of impacts. Through the use of pre-designed queries, impacts by origin, mode, fuel type or many other parameters can be obtained.

  4. Subsurface Uranium Fate and Transport: Integrated Experiments and Modeling of Coupled Biogeochemical Mechanisms of Nanocrystalline Uraninite Oxidation by Fe(III)-(hydr)oxides - Project Final Report

    SciTech Connect (OSTI)

    Peyton, Brent M. [Montana State University; Timothy, Ginn R. [University of California Davis; Sani, Rajesh K. [South Dakota School of Mines and Technology

    2013-08-14T23:59:59.000Z

    Subsurface bacteria including sulfate reducing bacteria (SRB) reduce soluble U(VI) to insoluble U(IV) with subsequent precipitation of UO2. We have shown that SRB reduce U(VI) to nanometer-sized UO2 particles (1-5 nm) which are both intra- and extracellular, with UO2 inside the cell likely physically shielded from subsequent oxidation processes. We evaluated the UO2 nanoparticles produced by Desulfovibrio desulfuricans G20 under growth and non-growth conditions in the presence of lactate or pyruvate and sulfate, thiosulfate, or fumarate, using ultrafiltration and HR-TEM. Results showed that a significant mass fraction of bioreduced U (35-60%) existed as a mobile phase when the initial concentration of U(VI) was 160 µM. Further experiments with different initial U(VI) concentrations (25 - 900 ?M) in MTM with PIPES or bicarbonate buffers indicated that aggregation of uraninite depended on the initial concentrations of U(VI) and type of buffer. It is known that under some conditions SRB-mediated UO2 nanocrystals can be reoxidized (and thus remobilized) by Fe(III)-(hydr)oxides, common constituents of soils and sediments. To elucidate the mechanism of UO2 reoxidation by Fe(III) (hydr)oxides, we studied the impact of Fe and U chelating compounds (citrate, NTA, and EDTA) on reoxidation rates. Experiments were conducted in anaerobic batch systems in PIPES buffer. Results showed EDTA significantly accelerated UO2 reoxidation with an initial rate of 9.5?M day-1 for ferrihydrite. In all cases, bicarbonate increased the rate and extent of UO2 reoxidation with ferrihydrite. The highest rate of UO2 reoxidation occurred when the chelator promoted UO2 and Fe(III) (hydr)oxide dissolution as demonstrated with EDTA. When UO2 dissolution did not occur, UO2 reoxidation likely proceeded through an aqueous Fe(III) intermediate as observed for both NTA and citrate. To complement to these laboratory studies, we collected U-bearing samples from a surface seep at the Rifle field site and have measured elevated U concentrations in oxic iron-rich sediments. To translate experimental results into numerical analysis of U fate and transport, a reaction network was developed based on Sani et al. (2004) to simulate U(VI) bioreduction with concomitant UO2 reoxidation in the presence of hematite or ferrihydrite. The reduction phase considers SRB reduction (using lactate) with the reductive dissolution of Fe(III) solids, which is set to be microbially mediated as well as abiotically driven by sulfide. Model results show the oxidation of HS– by Fe(III) directly competes with UO2 reoxidation as Fe(III) oxidizes HS– preferentially over UO2. The majority of Fe reduction is predicted to be abiotic, with ferrihydrite becoming fully consumed by reaction with sulfide. Predicted total dissolved carbonate concentrations from the degradation of lactate are elevated (log(pCO2) ~ –1) and, in the hematite system, yield close to two orders-of-magnitude higher U(VI) concentrations than under initial carbonate concentrations of 3 mM. Modeling of U(VI) bioreduction with concomitant reoxidation of UO2 in the presence of ferrihydrite was also extended to a two-dimensional field-scale groundwater flow and biogeochemically reactive transport model for the South Oyster site in eastern Virginia. This model was developed to simulate the field-scale immobilization and subsequent reoxidation of U by a biologically mediated reaction network.

  5. Heavy Duty Diesel Particulate Matter and Fuel Consumption Modeling for Transportation Analysis

    E-Print Network [OSTI]

    Scora, George Alexander

    2011-01-01T23:59:59.000Z

    measured second-by-second fuel use. Mesoscale Modeling DataSet and Mesoscale ModelCalibration Mesoscale model calibration and validation

  6. Grand challenge problems in environmental modeling and remediation: Groundwater contaminant transport. Final project report 1998

    SciTech Connect (OSTI)

    NONE

    1998-04-01T23:59:59.000Z

    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 Groundwater Grand Challenge project funded through the High Performance Computing grand challenge program of the Department of Energy from 1995 through 1997.

  7. Modeling most likely pathways for smuggling radioactive and special nuclear materials on a worldwide multimodal transportation network

    SciTech Connect (OSTI)

    Saeger, Kevin J [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    Nuclear weapons proliferation is an existing and growing worldwide problem. To help with devising strategies and supporting decisions to interdict the transport of nuclear material, we developed the Pathway Analysis, Threat Response and Interdiction Options Tool (PATRIOT) that provides an analytical approach for evaluating the probability that an adversary smuggling radioactive or special nuclear material will be detected during transit. We incorporate a global, multi-modal transportation network, explicit representation of designed and serendipitous detection opportunities, and multiple threat devices, material types, and shielding levels. This paper presents the general structure of PATRIOT, and focuses on the theoretical framework used to model the reliabilities of all network components that are used to predict the most likely pathways to the target.

  8. Modeling most likely pathways for smuggling radioactive and special nuclear materials on a worldwide multi-modal transportation network

    SciTech Connect (OSTI)

    Saeger, Kevin J [Los Alamos National Laboratory; Cuellar, Leticia [Los Alamos National Laboratory

    2010-10-28T23:59:59.000Z

    Nuclear weapons proliferation is an existing and growing worldwide problem. To help with devising strategies and supporting decisions to interdict the transport of nuclear material, we developed the Pathway Analysis, Threat Response and Interdiction Options Tool (PATRIOT) that provides an analytical approach for evaluating the probability that an adversary smuggling radioactive or special nuclear material will be detected during transit. We incorporate a global, multi-modal transportation network, explicit representation of designed and serendipitous detection opportunities, and multiple threat devices, material types, and shielding levels. This paper presents the general structure of PATRIOT, all focuses on the theoretical framework used to model the reliabilities of all network components that are used to predict the most likely pathways to the target.

  9. Structural fluctuations and quantum transport through DNA molecular wires: a combined molecular dynamics and model Hamiltonian approach

    E-Print Network [OSTI]

    R. Gutierrez; R. Caetano; P. B. Woiczikowski; T. Kubar; M. Elstner; G. Cuniberti

    2009-10-02T23:59:59.000Z

    Charge transport through a short DNA oligomer (Dickerson dodecamer) in presence of structural fluctuations is investigated using a hybrid computational methodology based on a combination of quantum mechanical electronic structure calculations and classical molecular dynamics simulations with a model Hamiltonian approach. Based on a fragment orbital description, the DNA electronic structure can be coarse-grained in a very efficient way. The influence of dynamical fluctuations arising either from the solvent fluctuations or from base-pair vibrational modes can be taken into account in a straightforward way through time series of the effective DNA electronic parameters, evaluated at snapshots along the MD trajectory. We show that charge transport can be promoted through the coupling to solvent fluctuations, which gate the onsite energies along the DNA wire.

  10. Charge transport through bio-molecular wires in a solvent: Bridging molecular dynamics and model Hamiltonian approaches

    E-Print Network [OSTI]

    R. Gutierrez; R. Caetano; P. B. Woiczikowski; T. Kubar; M. Elstner; G. Cuniberti

    2009-01-22T23:59:59.000Z

    We present a hybrid method based on a combination of quantum/classical molecular dynamics (MD) simulations and a mod el Hamiltonian approach to describe charge transport through bio-molecular wires with variable lengths in presence o f a solvent. The core of our approach consists in a mapping of the bio-molecular electronic structure, as obtained f rom density-functional based tight-binding calculations of molecular structures along MD trajectories, onto a low di mensional model Hamiltonian including the coupling to a dissipative bosonic environment. The latter encodes fluctuat ion effects arising from the solvent and from the molecular conformational dynamics. We apply this approach to the c ase of pG-pC and pA-pT DNA oligomers as paradigmatic cases and show that the DNA conformational fluctuations are essential in determining and supporting charge transport.

  11. Validation, Proof-of-Concept, and Postaudit of the Groundwater Flow and Transport Model of the Project Shoal Area

    SciTech Connect (OSTI)

    Ahmed Hassan

    2004-09-01T23:59:59.000Z

    The groundwater flow and radionuclide transport model characterizing the Shoal underground nuclear test has been accepted by the State of Nevada Division of Environmental Protection. According to the Federal Facility Agreement and Consent Order (FFACO) between DOE and the State of Nevada, the next steps in the closure process for the site are then model validation (or postaudit), the proof-of-concept, and the long-term monitoring stage. This report addresses the development of the validation strategy for the Shoal model, needed for preparing the subsurface Corrective Action Decision Document-Corrective Action Plan and the development of the proof-of-concept tools needed during the five-year monitoring/validation period. The approach builds on a previous model, but is adapted and modified to the site-specific conditions and challenges of the Shoal site.

  12. Computational Fuel Cell Research and SOFC Modeling at Penn State

    E-Print Network [OSTI]

    multidisciplinary research on fuel cells and advanced batteries for vehicle propulsion, distributed power generation science, multiphase transport, reactive flow, CFD modeling, experimental diagnostics, in- vehicle testing, DMFC, and SOFC #12;ECEC Facilities (>5,000 sq ft) Fuel Cell/Battery Experimental Labs Fuel Cell

  13. Effects of pore-scale velocity and pore-scale physical processes on contaminant biodegradation during transport in groundwater: modeling and experiments

    E-Print Network [OSTI]

    Mendoza Sanchez, Itza

    2009-05-15T23:59:59.000Z

    EFFECTS OF PORE-SCALE VELOCITY AND PORE-SCALE PHYSICAL PROCESSES ON CONTAMINANT BIODEGRADATION DURING TRANSPORT IN GROUNDWATER: MODELING AND EXPERIMENTS A Dissertation by ITZA MENDOZA SANCHEZ Submitted to the Office... PROCESSES ON CONTAMINANT BIODEGRADATION DURING TRANSPORT IN GROUNDWATER: MODELING AND EXPERIMENTS A Dissertation by ITZA MENDOZA SANCHEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  14. Effects of pore-scale velocity and pore-scale physical processes on contaminant biodegradation during transport in groundwater: modeling and experiments

    E-Print Network [OSTI]

    Mendoza Sanchez, Itza

    2008-10-10T23:59:59.000Z

    EFFECTS OF PORE-SCALE VELOCITY AND PORE-SCALE PHYSICAL PROCESSES ON CONTAMINANT BIODEGRADATION DURING TRANSPORT IN GROUNDWATER: MODELING AND EXPERIMENTS A Dissertation by ITZA MENDOZA SANCHEZ Submitted to the Office... PROCESSES ON CONTAMINANT BIODEGRADATION DURING TRANSPORT IN GROUNDWATER: MODELING AND EXPERIMENTS A Dissertation by ITZA MENDOZA SANCHEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

  15. A Tariff for Reactive Power

    SciTech Connect (OSTI)

    Kueck, John D [ORNL; Kirby, Brendan J [ORNL; Li, Fangxing [ORNL; Tufon, Christopher [Pacific Gas and Electric Company; Isemonger, Alan [California Independent System Operator

    2008-07-01T23:59:59.000Z

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce system losses, increase circuit capacity, increase reliability, and improve efficiency. Reactive power is theoretically available from any inverter-based equipment such as photovoltaic (PV) systems, fuel cells, microturbines, and adjustable-speed drives. However, the installation is usually only economical if reactive power supply is considered during the design and construction phase. In this report, we find that if the inverters of PV systems or the generators of combined heat and power (CHP) systems were designed with capability to supply dynamic reactive power, they could do this quite economically. In fact, on an annualized basis, these inverters and generators may be able to supply dynamic reactive power for about $5 or $6 per kVAR. The savings from the local supply of dynamic reactive power would be in reduced losses, increased capacity, and decreased transmission congestion. The net savings are estimated to be about $7 per kVAR on an annualized basis for a hypothetical circuit. Thus the distribution company could economically purchase a dynamic reactive power service from customers for perhaps $6/kVAR. This practice would provide for better voltage regulation in the distribution system and would provide an alternate revenue source to help amortize the cost of PV and CHP installations. As distribution and transmission systems are operated under rising levels of stress, the value of local dynamic reactive supply is expected to grow. Also, large power inverters, in the range of 500 kW to 1 MW, are expected to decrease in cost as they become mass produced. This report provides one data point which shows that the local supply of dynamic reactive power is marginally profitable at present for a hypothetical circuit. We expect that the trends of growing power flow on the existing system and mass production of inverters for distributed energy devices will make the dynamic supply of reactive power from customers an integral component of economical and reliable system operation in the future.

  16. MODELLING OF WAVE DRIVEN SEDIMENT TRANSPORT OVER A PARTIALLY BURIED CYLINDER

    E-Print Network [OSTI]

    Grilli, Stéphan T.

    be arbitrary; here, only cases with periodic waves are presented. We discuss wave induced boundary-layer flows to date has usually been based on specifying a simple oscillatory flow to force the sediment transport Fully Nonlinear Potential Flow (FNPF) equations, based on a higher-order Boundary Element Method (BEM

  17. Modeling transport of dissolved silica in a forested headwater catchment: Implications for defining the hydrochemical

    E-Print Network [OSTI]

    Scanlon, Todd

    in groundwater to be related to the saturation deficit in this zone. A positive correlation between the average and have emphasized the need for a rational, nonempirical approach for the identification stream water chemistry can provide valuable insight into the transport of dissolved materials

  18. Multiscale modeling of fluid transport in heterogeneous materials using discrete Boltzmann methods

    E-Print Network [OSTI]

    Bentz, Dale P.

    transport in porous materials like ceramics, concrete, soils, and rocks plays an impor- tant role in many geometries like porous materials. Here, we review some of our previous work and discuss some recent environmental and technological processes [11.For example, the service life and durability of concrete can

  19. EBS Radionuclide Transport Abstraction

    SciTech Connect (OSTI)

    J. Prouty

    2006-07-14T23:59:59.000Z

    The purpose of this report is to develop and analyze the engineered barrier system (EBS) radionuclide transport abstraction model, consistent with Level I and Level II model validation, as identified in Technical Work Plan for: Near-Field Environment and Transport: Engineered Barrier System: Radionuclide Transport Abstraction Model Report Integration (BSC 2005 [DIRS 173617]). The EBS radionuclide transport abstraction (or EBS RT Abstraction) is the conceptual model used in the total system performance assessment (TSPA) to determine the rate of radionuclide releases from the EBS to the unsaturated zone (UZ). The EBS RT Abstraction conceptual model consists of two main components: a flow model and a transport model. Both models are developed mathematically from first principles in order to show explicitly what assumptions, simplifications, and approximations are incorporated into the models used in the TSPA. The flow model defines the pathways for water flow in the EBS and specifies how the flow rate is computed in each pathway. Input to this model includes the seepage flux into a drift. The seepage flux is potentially split by the drip shield, with some (or all) of the flux being diverted by the drip shield and some passing through breaches in the drip shield that might result from corrosion or seismic damage. The flux through drip shield breaches is potentially split by the waste package, with some (or all) of the flux being diverted by the waste package and some passing through waste package breaches that might result from corrosion or seismic damage. Neither the drip shield nor the waste package survives an igneous intrusion, so the flux splitting submodel is not used in the igneous scenario class. The flow model is validated in an independent model validation technical review. The drip shield and waste package flux splitting algorithms are developed and validated using experimental data. The transport model considers advective transport and diffusive transport from a breached waste package. Advective transport occurs when radionuclides that are dissolved or sorbed onto colloids (or both) are carried from the waste package by the portion of the seepage flux that passes through waste package breaches. Diffusive transport occurs as a result of a gradient in radionuclide concentration and may take place while advective transport is also occurring, as well as when no advective transport is occurring. Diffusive transport is addressed in detail because it is the sole means of transport when there is no flow through a waste package, which may dominate during the regulatory compliance period in the nominal and seismic scenarios. The advective transport rate, when it occurs, is generally greater than the diffusive transport rate. Colloid-facilitated advective and diffusive transport is also modeled and is presented in detail in Appendix B of this report.

  20. Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

    SciTech Connect (OSTI)

    Rogers, J.D.

    1994-08-04T23:59:59.000Z

    This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.