Sample records for reaction transport model

  1. A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

    SciTech Connect (OSTI)

    Zhang, Fan [ORNL; Yeh, Gour-Tsyh [University of Central Florida, Orlando; Parker, Jack C [ORNL; Brooks, Scott C [ORNL; Pace, Molly [ORNL; Kim, Young Jin [ORNL; Jardine, Philip M [ORNL; Watson, David B [ORNL

    2007-01-01T23:59:59.000Z

    This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing NE equilibrium reactions and a set of reactive transport equations of M-NE kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.

  2. Modeling of transport and reaction in an engineered barrier for radioactive waste confinement

    E-Print Network [OSTI]

    Montes-Hernandez, German

    Modeling of transport and reaction in an engineered barrier for radioactive waste confinement G bentonite; Radioactive waste; Modelling; KIRMAT code; Chemical transformations; Mass transport 0169;1. Introduction A particular radioactive waste disposal design proposes to store waste in deep geological layers

  3. 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

  4. Transport Model Simulations of Projectile Fragmentation Reactions at 140 MeV/nucleon

    E-Print Network [OSTI]

    Mocko, M; Lacroix, D; Ono, A; Danielewicz, P; Lynch, W G; Charity, R J

    2008-01-01T23:59:59.000Z

    The collisions in four different reaction systems using 40,48Ca and 58,64Ni isotope beams and a Be target have been simulated using the Heavy Ion Phase Space Exploration and the Antisymmetrized Molecular Dynamics models. The present study mainly focuses on the model predictions of excitation energy of the hot fragments and the cross sections of final fragments produced in these reactions. The calculated fragment cross sections are compared to the published projectile fragmentation cross sections measured with a mass separator. Experimental efficiency-correction assumptions and their effects in validation of event generator codes are discussed in the light of the reaction dynamics described by these two models. The effects of various factors influencing the calculated cross sections, such as the choice of the statistical decay code and its parameters have been explored. Present study suggests that the CPU requirements and the uncertainties of model parameters including the influence of sequential decay effects...

  5. Final report on LDRD project: A phenomenological model for multicomponent transport with simultaneous electrochemical reactions in concentrated solutions

    SciTech Connect (OSTI)

    CHEN,KEN S.; EVANS,GREGORY H.; LARSON,RICHARD S.; NOBLE,DAVID R.; HOUF,WILLIAM G.

    2000-01-01T23:59:59.000Z

    A phenomenological model was developed for multicomponent transport of charged species with simultaneous electrochemical reactions in concentrated solutions, and was applied to model processes in a thermal battery cell. A new general framework was formulated and implemented in GOMA (a multidimensional, multiphysics, finite-element computer code developed and being enhanced at Sandia) for modeling multidimensional, multicomponent transport of neutral and charged species in concentrated solutions. The new framework utilizes the Stefan-Maxwell equations that describe multicomponent diffusion of interacting species using composition-insensitive binary diffusion coefficients. The new GOMA capability for modeling multicomponent transport of neutral species was verified and validated using the model problem of ternary gaseous diffusion in a Stefan tube. The new GOMA-based thermal battery computer model was verified using an idealized battery cell in which concentration gradients are absent; the full model was verified by comparing with that of Bernardi and Newman (1987) and validated using limited thermal battery discharge-performance data from the open literature (Dunning 1981) and from Sandia (Guidotti 1996). Moreover, a new Liquid Chemkin Software Package was developed, which allows the user to handle manly aspects of liquid-phase kinetics, thermodynamics, and transport (particularly in terms of computing properties). Lastly, a Lattice-Boltzmann-based capability was developed for modeling pore- or micro-scale phenomena involving convection, diffusion, and simplified chemistry; this capability was demonstrated by modeling phenomena in the cathode region of a thermal battery cell.

  6. Transport model simulations of projectile fragmentation reactions at 140 MeV/nucleon

    SciTech Connect (OSTI)

    Mocko, M. [Los Alamos National Laboratory, Post Office Box 1663, Los Alamos, New Mexico 87545 (United States); National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Tsang, M. B.; Danielewicz, P.; Lynch, W. G. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Lacroix, D. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Ganil, CEA, IN2P3-CNRS, Boite Postal 5027, F-14021 Caen Cedex (France); Ono, A. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Charity, R. J. [Chemistry Department, Washington University, St. Louis, Missouri 63130 (United States)

    2008-08-15T23:59:59.000Z

    The collisions in four different reaction systems using {sup 40,48}Ca and {sup 58,64}Ni isotope beams and a Be target have been simulated using the heavy ion phase space exploration and the antisymmetrized molecular dynamics models. The present study mainly focuses on the model predictions for the excitation energies of the hot fragments and the cross sections of the final fragments produced in these reactions. The effects of various factors influencing the final fragment cross sections, such as the choice of the statistical decay code and its parameters, have been explored. The predicted fragment cross sections are compared to the projectile fragmentation cross sections measured with the A1900 mass separator. At E/A=140 MeV, reaction dynamics can significantly modify the detection efficiencies for the fragments and make them different from the efficiencies applied to the measured data reported in the previous work. The effects of efficiency corrections on the validation of event generator codes are discussed in the context of the two models.

  7. Transport Model Simulations of Projectile Fragmentation Reactions at 140 MeV/nucleon

    E-Print Network [OSTI]

    M. Mocko; M. B. Tsang; D. Lacroix; A. Ono; P. Danielewicz; W. G. Lynch; R. J. Charity

    2008-04-16T23:59:59.000Z

    The collisions in four different reaction systems using $^{40,48}$Ca and $^{58,64}$Ni isotope beams and a Be target have been simulated using the Heavy Ion Phase Space Exploration and the Antisymmetrized Molecular Dynamics models. The present study mainly focuses on the model predictions for the excitation energies of the hot fragments and the cross sections of the final fragments produced in these reactions. The effects of various factors influencing the final fragment cross sections, such as the choice of the statistical decay code and its parameters have been explored. The predicted fragment cross sections are compared to the projectile fragmentation cross sections measured with the A1900 mass separator. At $E/A=140$ MeV, reaction dynamics can significantly modify the detection efficiencies for the fragments and make them different from the efficiencies applied to the measured data reported in the previous work. The effects of efficiency corrections on the validation of event generator codes are discussed in the context of the two models.

  8. 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.

  9. A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed.

    SciTech Connect (OSTI)

    Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E.

    2013-03-01T23:59:59.000Z

    Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model.

  10. UZ Colloid Transport Model

    SciTech Connect (OSTI)

    M. McGraw

    2000-04-13T23:59:59.000Z

    The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations.

  11. The role of nuclear reactions and -particle transport in the dynamics of inertial confinement fusion capsules

    E-Print Network [OSTI]

    Garnier, Josselin

    The role of nuclear reactions and -particle transport in the dynamics of inertial confinement fusion capsules Josselin Garnier1,a and Catherine Cherfils-Clérouin2 1 Laboratoire de Probabilités et the energy released by nuclear reactions, a nonlocal model for the -particle energy deposition process

  12. Towards Quantum Transport for Nuclear Reactions

    E-Print Network [OSTI]

    Danielewicz, Pawel; Barker, Brent

    2009-01-01T23:59:59.000Z

    Nonequilibrium Green's functions represent a promising tool for describing central nuclear reactions. Even at the single-particle level, though, the Green's functions contain more information that computers may handle in the foreseeable future. In this study, we investigate whether all the information contained in the Green's functions is necessarily relevant when describing the time evolution of nuclear reactions. For this, we carry out mean-field calculations of slab collisions in one dimension.

  13. Towards Quantum Transport for Nuclear Reactions

    E-Print Network [OSTI]

    Pawel Danielewicz; Arnau Rios; Brent Barker

    2009-06-26T23:59:59.000Z

    Nonequilibrium Green's functions represent a promising tool for describing central nuclear reactions. Even at the single-particle level, though, the Green's functions contain more information that computers may handle in the foreseeable future. In this study, we investigate whether all the information contained in the Green's functions is necessarily relevant when describing the time evolution of nuclear reactions. For this, we carry out mean-field calculations of slab collisions in one dimension.

  14. 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;

  15. Generalized solution to multispecies transport equations coupled with a first-order reaction network

    E-Print Network [OSTI]

    Clement, Prabhakar

    Generalized solution to multispecies transport equations coupled with a first-order reaction for deriving analytical solutions to multispecies transport equations coupled with multiparent, serial multispecies transport equations with different retardation factors. Mathematical steps are provided

  16. 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

  17. An integrated experimental and numerical study: Developing a reaction transport model that couples chemical reactions of mineral dissolution/precipitation with spatial and temporal flow variations in CO2/brine/rock systems

    Broader source: Energy.gov [DOE]

    Project objectives: Generate and characterize mineral dissolution/precipitation reactions in supercritical CO2/brine/rock systems under pressure-temperature-chemistry conditions resembling CO2injection into EGS. Characterize three-dimensional spatial and temporal distributions of rock structures subject to mineral dissolution/precipitation processes by X-ray tomography, SEM imaging, and Microprobe analysis.

  18. Serpentinization reaction pathways: implications for modeling approach

    SciTech Connect (OSTI)

    Janecky, D.R.

    1986-01-01T23:59:59.000Z

    Experimental seawater-peridotite reaction pathways to form serpentinites at 300/sup 0/C, 500 bars, can be accurately modeled using the EQ3/6 codes in conjunction with thermodynamic and kinetic data from the literature and unpublished compilations. These models provide both confirmation of experimental interpretations and more detailed insight into hydrothermal reaction processes within the oceanic crust. The accuracy of these models depends on careful evaluation of the aqueous speciation model, use of mineral compositions that closely reproduce compositions in the experiments, and definition of realistic reactive components in terms of composition, thermodynamic data, and reaction rates.

  19. Solar Models and NACRE thermonuclear reaction rates

    E-Print Network [OSTI]

    P. Morel; B. Pichon; J. Provost; G. Berthomieu

    1999-07-27T23:59:59.000Z

    Using the most recent updated physics, calibrated solar models have been computed with the new thermonuclear reaction rates of NACRE, the recently available European compilation. Comparisons with models computed with the reaction rates of Caughlan & Fowler (\\cite{cf88}) and of Adelberger et al. (\\cite{a98}) are made for global structure, expected neutrinos fluxes, chemical composition and sound speed profiles, helioseismological properties of p-modes and g-modes.

  20. 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

  1. 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.

  2. 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.

  3. Modeling reaction time within a traffic simulation model

    E-Print Network [OSTI]

    Basak, Kakali

    Human reaction time has a substantial effect on modeling of human behavior at a microscopic level. Drivers and pedestrian do not react to an event instantaneously; rather, they take time to perceive the event, process the ...

  4. 5. Energy Production and Transport 5.1 Energy Release from Nuclear Reactions

    E-Print Network [OSTI]

    Peletier, Reynier

    5. Energy Production and Transport 5.1 Energy Release from Nuclear Reactions As mentioned when we looked at energy generation, it is now known that most of the energy radiated by stars must be released by nuclear reactions. In this section we will consider why it is that energy can be released by nuclear

  5. 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

  6. Stopping and Baryon Transport in Heavy Ion Reactions

    E-Print Network [OSTI]

    F. Videbaek

    2005-05-10T23:59:59.000Z

    In this report I will give an experimental overview on nuclear stopping in hadron collisions, and relate observations to understanding of baryon transport. Baryon number transport is not only evidenced via net-proton distributions but also by the enhancement of strange baryons near mid-rapidity. Although the focus is on high-energy data obtained from pp and heavy ions from RHIC, relevant data from SPS and ISR will be considered. A discussion how the available data at higher energy relates and gives information on baryon junction, quark-diquark breaking will be made.

  7. PROCESS SYSTEMS ENGINEERING Discovery of Transport and Reaction

    E-Print Network [OSTI]

    Linninger, Andreas A.

    .interscience.wiley.com). In distributed systems, transport phenomena coupled with chemical or metabolic reac- tions are functions of space, which can often not be achieved in the real processes. Moreover, in many biological systems and safety, their extrapolation to larger reactor dimen- sions or different configuration can become unreliable. Parameter

  8. Ammonium transport and reaction in contaminated groundwater: Application of isotope tracers and isotope fractionation studies

    E-Print Network [OSTI]

    Ammonium transport and reaction in contaminated groundwater: Application of isotope tracers the groundwater velocity. Retardation factors and groundwater ages indicate that much of the NH4 + in the plume was recharged early in the history of the wastewater disposal. NO3 ? and excess N2 gas, which were related

  9. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    -mouth generation at Powder River Basin How much impact would 25% wind penetration have on price ? 2 What is modeled spatial & temporal energy flows nodal prices (fuel & elec) SO2, allowance price1 Decision Models for Bulk Energy Transportation Networks Electrical Engineering Professor Jim Mc

  10. Upscaling geochemical reaction rates using pore-scale network modeling

    E-Print Network [OSTI]

    Peters, Catherine A.

    . To examine the scaling behavior of reaction kinetics, these continuum-scale rates from the network model as a valuable research tool for examining upscaling of geochemical kinetics. The pore-scale model allowsUpscaling geochemical reaction rates using pore-scale network modeling Li Li, Catherine A. Peters

  11. INVESTIGATION OF MULTISCALE AND MULTIPHASE FLOW, TRANSPORT AND REACTION IN HEAVY OIL RECOVERY PROCESSES

    SciTech Connect (OSTI)

    Yannis C. Yortsos

    2003-02-01T23:59:59.000Z

    This is final report for contract DE-AC26-99BC15211. The report describes progress made in the various thrust areas of the project, which include internal drives for oil recovery, vapor-liquid flows, combustion and reaction processes and the flow of fluids with yield stress. The report consists mainly of a compilation of various topical reports, technical papers and research reports published produced during the three-year project, which ended on May 6, 2002 and was no-cost extended to January 5, 2003. Advances in multiple processes and at various scales are described. In the area of internal drives, significant research accomplishments were made in the modeling of gas-phase growth driven by mass transfer, as in solution-gas drive, and by heat transfer, as in internal steam drives. In the area of vapor-liquid flows, we studied various aspects of concurrent and countercurrent flows, including stability analyses of vapor-liquid counterflow, and the development of novel methods for the pore-network modeling of the mobilization of trapped phases and liquid-vapor phase changes. In the area of combustion, we developed new methods for the modeling of these processes at the continuum and pore-network scales. These models allow us to understand a number of important aspects of in-situ combustion, including steady-state front propagation, multiple steady-states, effects of heterogeneity and modes of combustion (forward or reverse). Additional aspects of reactive transport in porous media were also studied. Finally, significant advances were made in the flow and displacement of non-Newtonian fluids with Bingham plastic rheology, which is characteristic of various heavy oil processes. Various accomplishments in generic displacements in porous media and corresponding effects of reservoir heterogeneity are also cited.

  12. 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.

  13. 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.

  14. Method and apparatus for measuring coupled flow, transport, and reaction processes under liquid unsaturated flow conditions

    DOE Patents [OSTI]

    McGrail, Bernard P. (Pasco, WA); Martin, Paul F. (Richland, WA); Lindenmeier, Clark W. (Richland, WA)

    1999-01-01T23:59:59.000Z

    The present invention is a method and apparatus for measuring coupled flow, transport and reaction processes under liquid unsaturated flow conditions. The method and apparatus of the present invention permit distinguishing individual precipitation events and their effect on dissolution behavior isolated to the specific event. The present invention is especially useful for dynamically measuring hydraulic parameters when a chemical reaction occurs between a particulate material and either liquid or gas (e.g. air) or both, causing precipitation that changes the pore structure of the test material.

  15. EFFECTS OF PORE STRUCTURE CHANGE AND MULTI-SCALE HETEROGENEITY ON CONTAMINANT TRANSPORT AND REACTION RATE UPSCALING

    SciTech Connect (OSTI)

    Lindquist, W. Brent; Jones, Keith W.; Um, Wooyong; Rockhold, mark; Peters, Catherine A.; Celia, Michael A.

    2013-02-15T23:59:59.000Z

    This project addressed the scaling of geochemical reactions to core and field scales, and the interrelationship between reaction rates and flow in porous media. We targeted reactive transport problems relevant to the Hanford site ? specifically the reaction of highly caustic, radioactive waste solutions with subsurface sediments, and the immobilization of 90Sr and 129I through mineral incorporation and passive flow blockage, respectively. We addressed the correlation of results for pore-scale fluid-soil interaction with field-scale fluid flow, with the specific goals of (i) predicting attenuation of radionuclide concentration; (ii) estimating changes in flow rates through changes of soil permeabilities; and (iii) estimating effective reaction rates. In supplemental work, we also simulated reactive transport systems relevant to geologic carbon sequestration. As a whole, this research generated a better understanding of reactive transport in porous media, and resulted in more accurate methods for reaction rate upscaling and improved prediction of permeability evolution. These scientific advancements will ultimately lead to better tools for management and remediation of DOEs legacy waste problems. We established three key issues of reactive flow upscaling, and organized this project in three corresponding thrust areas. 1) Reactive flow experiments. The combination of mineral dissolution and precipitation alters pore network structure and the subsequent flow velocities, thereby creating a complex interaction between reaction and transport. To examine this phenomenon, we conducted controlled laboratory experimentation using reactive flow-through columns. ? Results and Key Findings: Four reactive column experiments (S1, S3, S4, S5) have been completed in which simulated tank waste leachage (STWL) was reacted with pure quartz sand, with and without Aluminum. The STWL is a caustic solution that dissolves quartz. Because Al is a necessary element in the formation of secondary mineral precipitates (cancrinite), conducting experiments under conditions with and without Al allowed us to experimentally separate the conditions that lead to quartz dissolution from the conditions that lead to quartz dissolution plus cancrinite precipitation. Consistent with our expectations, in the experiments without Al, there was a substantial reduction in volume of the solid matrix. With Al there was a net increase in the volume of the solid matrix. The rate and extent of reaction was found to increase with temperature. These results demonstrate a successful effort to identify conditions that lead to increases and conditions that lead to decreases in solid matrix volume due to reactions of caustic tank wastes with quartz sands. In addition, we have begun to work with slightly larger, intermediate-scale columns packed with Hanford natural sediments and quartz. Similar dissolution and precipitation were observed in these colums. The measurements are being interpreted with reactive transport modeling using STOMP; preliminary observations are reported here. 2) Multi-Scale Imaging and Analysis. Mineral dissolution and precipitation rates within a porous medium will be different in different pores due to natural heterogeneity and the heterogeneity that is created from the reactions themselves. We used a combination of X-ray computed microtomography, backscattered electron and energy dispersive X-ray spectroscopy combined with computational image analysis to quantify pore structure, mineral distribution, structure changes and fluid-air and fluid-grain interfaces. ? Results and Key Findings: Three of the columns from the reactive flow experiments at PNNL (S1, S3, S4) were imaged using 3D X-ray computed microtomography (XCMT) at BNL and analyzed using 3DMA-rock at SUNY Stony Brook. The imaging results support the mass balance findings reported by Dr. Ums group, regarding the substantial dissolution of quartz in column S1. An important observation is that of grain movement accompanying dissolution in the unconsolidated media. The resultant movement

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. Azimuthal Anisotropies as Stringent Test for Nuclear Transport Models

    E-Print Network [OSTI]

    P. Crochet; F. Rami; R. Dona; the FOPI Collaboration

    1997-09-15T23:59:59.000Z

    Azimuthal distributions of charged particles and intermediate mass fragments emitted in Au+Au collisions at 600AMeV have been measured using the FOPI facility at GSI-Darmstadt. Data show a strong increase of the in-plane azimuthal anisotropy ratio with the charge of the detected fragment. Intermediate mass fragments are found to exhibit a strong momentum-space alignment with respect of the reaction plane. The experimental results are presented as a function of the polar center-of-mass angle and over a broad range of impact parameters. They are compared to the predictions of the Isospin Quantum Molecular Dynamics model using three different parametrisations of the equation of state. We show that such highly accurate data provide stringent test for microscopic transport models and can potentially constrain separately the stiffness of the nuclear equation of state and the momentum dependence of the nuclear interaction.

  2. 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...

  3. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    SciTech Connect (OSTI)

    Yortsos, Yanis C.

    2001-08-07T23:59:59.000Z

    This project is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  4. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    SciTech Connect (OSTI)

    Yortsos, Y.C.

    2001-05-29T23:59:59.000Z

    This report is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  5. Strong plasma screening in thermonuclear reactions: Electron drop model

    E-Print Network [OSTI]

    Kravchuk, P A

    2014-01-01T23:59:59.000Z

    We analyze enhancement of thermonuclear fusion reactions due to strong plasma screening in dense matter using a simple electron drop model. The model assumes fusion in a potential that is screened by an effective electron cloud around colliding nuclei (extended Salpeter ion-sphere model). We calculate the mean field screened Coulomb potentials for atomic nuclei with equal and nonequal charges, appropriate astrophysical S factors, and enhancement factors of reaction rates. As a byproduct, we study analytic behavior of the screening potential at small separations between the reactants. In this model, astrophysical S factors depend not only on nuclear physics but on plasma screening as well. The enhancement factors are in good agreement with calculations by other methods. This allows us to formulate the combined, pure analytic model of strong plasma screening in thermonuclear reactions. The results can be useful for simulating nuclear burning in white dwarfs and neutron stars.

  6. Strong plasma screening in thermonuclear reactions: Electron drop model

    E-Print Network [OSTI]

    P. A. Kravchuk; D. G. Yakovlev

    2014-01-11T23:59:59.000Z

    We analyze enhancement of thermonuclear fusion reactions due to strong plasma screening in dense matter using a simple electron drop model. The model assumes fusion in a potential that is screened by an effective electron cloud around colliding nuclei (extended Salpeter ion-sphere model). We calculate the mean field screened Coulomb potentials for atomic nuclei with equal and nonequal charges, appropriate astrophysical S factors, and enhancement factors of reaction rates. As a byproduct, we study analytic behavior of the screening potential at small separations between the reactants. In this model, astrophysical S factors depend not only on nuclear physics but on plasma screening as well. The enhancement factors are in good agreement with calculations by other methods. This allows us to formulate the combined, pure analytic model of strong plasma screening in thermonuclear reactions. The results can be useful for simulating nuclear burning in white dwarfs and neutron stars.

  7. Modeling Carrier Behavior in Sequential Auction Transportation Markets

    E-Print Network [OSTI]

    Bertini, Robert L.

    Modeling Carrier Behavior in Sequential Auction Transportation Markets M. A. Figliozzi, University ______________________________________________________________________________ August 10-15, 2003 2 Title: Modeling Carrier Behavior in Sequential Auction Transportation Markets Miguel Phone: 301-405-0752 Fax: 301-405-2585 eMail: masmah@umd.edu Abstract Online markets for transportation

  8. Light radioactive nuclei capture reactions with phenomenological potential models

    E-Print Network [OSTI]

    V. Guimaraes; C. A. Bertulani

    2009-12-01T23:59:59.000Z

    Light radioactive nuclei play an important role in many astrophysical environments. Due to very low cross sections of some neutron and proton capture reactions by these radioactive nuclei at energies of astrophysical interest, direct laboratory measurements are very difficult. For radioactive nuclei such as 8Li and 8B, the direct measurement of neutron capture reactions is impossible. Indirect methods have been applied to overcome these difficulties. In this work we will report on the results and discussion of phenomenological potential models used to determine some proton and neutron capture reactions. As a test we show the results for the 16O(p,g)17F_gs(5/2+) and 16O(p,g)17F_ex(1/2+) capture reactions.We also computed the nucleosynthesis cross sections for the 7Li(n,g)8Li, 8Li(n,g)9Li and 8B(p,g)9C capture reactions.

  9. 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.

  10. Comb models for transport along spiny dendrites

    E-Print Network [OSTI]

    Mndez, 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. Singular Vector Analysis for Atmospheric Chemical Transport Models

    E-Print Network [OSTI]

    Sandu, Adrian

    are presented for a simulation of atmospheric pollution in East Asia in March 2001. The singular valuesSingular Vector Analysis for Atmospheric Chemical Transport Models Wenyuan Liao and Adrian Sandu for atmospheric chemical transport models. The distinguishing feature of these models is the presence of stiff

  12. 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

  13. 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

  14. 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...

  15. 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...

  16. Modeling Oxygen Transport in Three-Dimensional Capillary Networks.

    E-Print Network [OSTI]

    Fraser, Graham M

    2012-01-01T23:59:59.000Z

    ??The purpose of this thesis was to examine how the use of real 3-dimensional (3D) capillary network geometries affect models of oxygen transport to tissue. (more)

  17. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    SciTech Connect (OSTI)

    Yorstos, Yanis C.

    2002-03-11T23:59:59.000Z

    The emphasis of this work was on investigating the mechanisms and factors that control the recovery of heavy oil with the objective to improve recovery efficiencies. For this purpose the interaction of flow transport and reaction at various scales from the pore network to the field scales were studied. Particular mechanisms to be investigated included the onset of gas flow in foamy oil production and in in-situ steam drive, gravity drainage in steam processes, the development of sustained combustion fronts and the propagation of foams in porous media. Analytical, computational and experimental methods were utilized to advance the state of the art in heavy oil recovery. Successful completion of this research was expected to lead to improvements in the Recovery efficiency of various heavy oil processes.

  18. Transverse transport of solutes between co-flowing pressure-driven streams for microfluidic studies of diffusion/reaction processes

    E-Print Network [OSTI]

    Jean-Baptiste Salmon; Armand Ajdari

    2007-02-01T23:59:59.000Z

    We consider a situation commonly encountered in microfluidics: two streams of miscible liquids are brought at a junction to flow side by side within a microchannel, allowing solutes to diffuse from one stream to the other and possibly react. We focus on two model problems: (i) the transverse transport of a single solute from a stream into the adjacent one, (ii) the transport of the product of a diffusion-controlled chemical reaction between solutes originating from the two streams. Our description is made general through a non-dimensionalized formulation that incorporates both the parabolic Poiseuille velocity profile along the channel and thermal diffusion in the transverse direction. Numerical analysis over a wide range of the streamwise coordinate $x$ reveal different regimes. Close to the top and the bottom walls of the microchannel, the extent of the diffusive zone follows three distinct power law regimes as $x$ is increased, characterized respectively by the exponents 1/2, 1/3 and 1/2. Simple analytical arguments are proposed to account for these results.

  19. Particle-scale CO2 adsorption kinetics modeling considering three reaction mechanisms

    SciTech Connect (OSTI)

    Suh, Dong-Myung; Sun, Xin

    2013-09-01T23:59:59.000Z

    In the presence of water (H2O), dry and wet adsorptions of carbon dioxide (CO2) and physical adsorption of H2O happen concurrently in a sorbent particle. The three reactions depend on each other and have a complicated, but important, effect on CO2 capturing via a solid sorbent. In this study, transport phenomena in the sorbent were modeled, including the tree reactions, and a numerical solving procedure for the model also was explained. The reaction variable distribution in the sorbent and their average values were calculated, and simulation results were compared with experimental data to validate the proposed model. Some differences, caused by thermodynamic parameters, were observed between them. However, the developed model reasonably simulated the adsorption behaviors of a sorbent. The weight gained by each adsorbed species, CO2 and H2O, is difficult to determine experimentally. It is known that more CO2 can be captured in the presence of water. Still, it is not yet known quantitatively how much more CO2 the sorbent can capture, nor is it known how much dry and wet adsorptions separately account for CO2 capture. This study addresses those questions by modeling CO2 adsorption in a particle and simulating the adsorption process using the model. As adsorption temperature changed into several values, the adsorbed amount of each species was calculated. The captured CO2 in the sorbent particle was compared quantitatively between dry and wet conditions. As the adsorption temperature decreased, wet adsorption increased. However, dry adsorption was reduced.

  20. Reaction mechanisms in transport theories: a test of the nuclear effective interaction

    E-Print Network [OSTI]

    M. Colonna; V. Baran; M. Di Toro; B. Frecus; Y. X. Zhang

    2012-09-07T23:59:59.000Z

    We review recent results concerning collective excitations in neutron-rich systems and reactions between charge asymmetric systems at Fermi energies. Solving numerically self-consistent transport equations for neutrons and protons with specific initial conditions, we explore the structure of the different dipole vibrations in the $^{132}Sn$ system and investigate their dependence on the symmetry energy. We evidence the existence of a distinctive collective mode, that can be associated with the Pygmy Dipole Resonance, with an energy well below the standard Giant Dipole Resonance and isoscalar-like character, i.e. very weakly dependent on the isovector part of the nuclear effective interaction. At variance, the corresponding strength is rather sensitive to the behavior of the symmetry energy below saturation, which rules the number of excess neutrons in the nuclear surface. In reactions between charge asymmetric systems at Fermi energies, we investigate the interplay between dissipation mechanisms and isospin effects. Observables sensitive to the isospin dependent part of nuclear interaction are discussed, providing information on the symmetry energy density dependence below saturation.

  1. HYDROGEOCHEM: A coupled model of HYDROlogic transport and GEOCHEMical equilibria in reactive multicomponent systems

    SciTech Connect (OSTI)

    Yeh, G.T.; Tripathi, V.S.

    1990-11-01T23:59:59.000Z

    This report presents the development of a hydrogeochemical transport model for multicomponent systems. The model is designed for applications to proper hydrological setting, accommodation of complete suite of geochemical equilibrium processes, easy extension to deal with chemical kinetics, and least constraints of computer resources. The hydrological environment to which the model can be applied is the heterogeneous, anisotropic, saturated-unsaturated subsurface media under either transient or steady state flow conditions. The geochemical equilibrium processes included in the model are aqueous complexation, adsorption-desorption, ion exchange, precipitation-dissolution, redox, and acid-base reactions. To achieve the inclusion of the full complement of these geochemical processes, total analytical concentrations of all chemical components are chosen as the primary dependent variables in the hydrological transport equations. Attendant benefits of this choice are to make the extension of the model to deal with kinetics of adsorption-desorption, ion exchange, precipitation-dissolution, and redox relatively easy. To make the negative concentrations during the iteration between the hydrological transport and geochemical equilibrium least likely, an implicit form of transport equations are proposed. To alleviate severe constraints of computer resources in terms of central processing unit (CPU) time and CPU memory, various optional numerical schemes are incorporated in the model. The model consists of a hydrological transport module and geochemical equilibrium module. Both modules were thoroughly tested in code consistency and were found to yield plausible results. The model is verified with ten examples. 79 refs., 21 figs., 17 tabs.

  2. Weakly screened thermonuclear reactions in astrophysical plasmas: Improving Salpeter's model

    E-Print Network [OSTI]

    Theodore E. Liolios

    2003-06-23T23:59:59.000Z

    This paper presents a detailed study of the electron degeneracy and nonlinear screening effects which play a crucial role in the validity of Salpeter's weak-screening model. The limitations of that model are investigated and an improved one is proposed which can take into account nonlinear screening effects. Its application to the solar pp reaction derives an accurate screening enhancement factor and provides a very reliable estimation of the associated neutrino flux uncertanties.

  3. 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

  4. MOMDIS: a Glauber model computer code for knockout reactions

    E-Print Network [OSTI]

    C. A. Bertulani; A. Gade

    2006-04-12T23:59:59.000Z

    A computer program is described to calculate momentum distributions in stripping and diffraction dissociation reactions. A Glauber model is used with the scattering wavefunctions calculated in the eikonal approximation. The program is appropriate for knockout reactions at intermediate energy collisions (30 MeV $\\leq$ E$_{lab}/$nucleon $\\leq 2000$ MeV). It is particularly useful for reactions involving unstable nuclear beams, or exotic nuclei (e.g. neutron-rich nuclei), and studies of single-particle occupancy probabilities (spectroscopic factors) and other related physical observables. Such studies are an essential part of the scientific program of radioactive beam facilities, as in for instance the proposed RIA (Rare Isotope Accelerator) facility in the US.

  5. Turbulent Flow and Transport Modeling by Long Waves and Currents

    E-Print Network [OSTI]

    Kim, Dae Hong

    2010-10-12T23:59:59.000Z

    This dissertation presents models for turbulent flow and transport by currents and long waves in large domain. From the Navier-Stokes equations, a fully nonlinear depth-integrated equation model for weakly dispersive, turbulent and rotational flow...

  6. 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.

  7. EFFECTS OF PORE STRUCTURE CHANGE AND MULTI-SCALE HETEROGENEITY ON CONTAMINANT TRANSPORT AND REACTION RATE UPSCALING

    SciTech Connect (OSTI)

    Peters, Catherine A [Princeton University] [Princeton University

    2013-05-15T23:59:59.000Z

    This project addressed the scaling of geochemical reactions to core and field scales, and the interrelationship between reaction rates and flow in porous media. We targeted reactive transport problems relevant to the Hanford site specifically the reaction of highly caustic, radioactive waste solutions with subsurface sediments, and the immobilization of 90Sr and 129I through mineral incorporation and passive flow blockage, respectively. We addressed the correlation of results for pore-scale fluid-soil interaction with field-scale fluid flow, with the specific goals of (i) predicting attenuation of radionuclide concentration; (ii) estimating changes in flow rates through changes of soil permeabilities; and (iii) estimating effective reaction rates. In supplemental work, we also simulated reactive transport systems relevant to geologic carbon sequestration. As a whole, this research generated a better understanding of reactive transport in porous media, and resulted in more accurate methods for reaction rate upscaling and improved prediction of permeability evolution. These scientific advancements will ultimately lead to better tools for management and remediation of DOE legacy waste problems.

  8. 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.

  9. 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...

  10. 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 ...

  11. Isospin transport in 84Kr+112,124Sn reactions at Fermi energies

    E-Print Network [OSTI]

    S. Piantelli; G. Casini; A. Olmi; S. Barlini; M. Bini; S. Carboni; P. R. Maurenzig; G. Pasquali; G. Poggi; A. A. Stefanini; R. Bougault; N. LeNeindre; O. Lopez; M. Parlog; E. Vient; E. Bonnet; A. Chbihi; J. D. Frankland; D. Gruyer; E. Rosato; G. Spadaccini; M. Vigilante; B. Borderie; M. F. Rivet; M. Bruno; L. Morelli; M. Cinausero; M. Degerlier; F. Gramegna; T. Marchi; R. Alba; C. Maiolino; D. Santonocito; T. Kozik; T. Twarog

    2013-09-06T23:59:59.000Z

    Isospin transport phenomena in dissipative heavy ion collisions have been investigated at Fermi energies with a beam of 84Kr at 35AMeV. A comparison of the /Z of light and medium products forward-emitted in the centre of mass frame when the beam impinges on a n-poor 112Sn and a n-rich 124Sn targets is presented. Data were collected by means of a three-layer telescope with very good performances in terms of mass identification (full isotopic resolution up to Z about 20 for ions punching through the first detector layer) built by the FAZIA Collaboration and located just beyond the grazing angle for both reactions. The /Z of the decay products emitted when the n-rich target is used is always higher than that associated to the n-poor one. Since the detector was able to measure only fragments coming from the QuasiProjectile decay and/or neck emission, the observed behaviour can be ascribed to the isospin diffusion, driven by the isospin gradient between QuasiProjectile and QuasiTarget. Moreover, for light fragments the /Z as a function of the lab velocity of the fragment increases when we move from the QuasiProjectile velocity to the centre of mass (neck zone). This effect can be interpreted as an evidence of isospin drift driven by the density gradient between the QuasiProjectile zone (at normal density) and the more diluted neck zone.

  12. Modeling atmospheric deposition using a stochastic transport model

    SciTech Connect (OSTI)

    Buckley, R.L.

    1999-12-17T23:59:59.000Z

    An advanced stochastic transport model has been modified to include the removal mechanisms of dry and wet deposition. Time-dependent wind and turbulence fields are generated with a prognostic mesoscale numerical model and are used to advect and disperse individually released particles that are each assigned a mass. These particles are subjected to mass reduction in two ways depending on their physical location. Particles near the surface experience a decrease in mass using the concept of a dry deposition velocity, while the mass of particles located within areas of precipitation are depleted using a scavenging coefficient. Two levels of complexity are incorporated into the particle model. The simple case assumes constant values of dry deposition velocity and scavenging coefficient, while the more complex case varies the values according to meteorology, surface conditions, release material, and precipitation intensity. Instantaneous and cumulative dry and wet deposition are determined from the mass loss due to these physical mechanisms. A useful means of validating the model results is with data available from a recent accidental release of Cesium-137 from a steel-processing furnace in Algeciras, Spain in May, 1998. This paper describes the deposition modeling technique, as well as a comparison of simulated concentration and deposition with measurements taken for the Algeciras release.

  13. 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

  14. Reactions of Lignin Model Compounds in Ionic Liquids

    SciTech Connect (OSTI)

    Holladay, John E.; Binder, Joseph B.; Gray, Michel J.; White, James F.; Zhang, Z. Conrad

    2009-09-15T23:59:59.000Z

    Lignin, a readily available form of biomass, awaits novel chemistry for converting it to valuable aromatic chemicals. Recent work has demonstrated that ionic liquids are excellent solvents for processing woody biomass and lignin. Seeking to exploit ionic liquids as media for depolymerization of lignin, we investigated reactions of lignin model compounds in these solvents. Using Brnsted acid catalysts in 1-ethyl-3-methylimidazolium triflate at moderate temperatures, we obtained up to 11.6% yield of the dealkylation product guaiacol from the model compound eugenol and cleaved phenethyl phenyl ether, a model for lignin ethers. Despite these successes, acid catalysis failed in dealkylation of the unsaturated model compound 4-ethylguaiacol and did not produce monomeric products from organosolv lignin, demonstrating that further work is required to understand the complex chemistry of lignin depolymerization.

  15. Deep sub-threshold $?$ and $?$ production in nuclear collisions with the UrQMD transport model

    E-Print Network [OSTI]

    G. Graef; J. Steinheimer; Feng Li; Marcus Bleicher

    2014-09-28T23:59:59.000Z

    We present results on deep sub threshold hyperon production in nuclear collisions, with the UrQMD transport model. Introducing anti-kaon+baryon and hyperon+hyperon strangeness exchange reactions we obtain a good description of experimental data on single strange hadron production in Ar+KCl reactions at $E_{lab}=1.76$ A GeV. We find that the hyperon strangeness exchange is the dominant process contributing to the $\\Xi^-$ yield, however remains short of explaining the $\\Xi^-/\\Lambda$ ratio measured with the HADES experiment. We also discuss possible reasons for the discrepancy with previous studies and the experimental results, finding that many details of the transport simulation may have significant effects on the final $\\Xi^-$ yield.

  16. 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.

  17. 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

    Using the kinematic-wave overland flow equation and a fractional dispersion-advection equation, a process-oriented, physically-based model is developed for overland solute transport. Two scenarios, one consisting of downslope and the other...

  18. Thermodynamic Data for Geochemical Modeling of Carbonate Reactions Associated with CO2 Sequestration Literature Review

    SciTech Connect (OSTI)

    Krupka, Kenneth M.; Cantrell, Kirk J.; McGrail, B. Peter

    2010-09-28T23:59:59.000Z

    Permanent storage of anthropogenic CO2 in deep geologic formations is being considered as a means to reduce the concentration of atmospheric CO2 and thus its contribution to global climate change. To ensure safe and effective geologic sequestration, numerous studies have been completed of the extent to which the CO2 migrates within geologic formations and what physical and geochemical changes occur in these formations when CO2 is injected. Sophisticated, computerized reservoir simulations are used as part of field site and laboratory CO2 sequestration studies. These simulations use coupled multiphase flow-reactive chemical transport models and/or standalone (i.e., no coupled fluid transport) geochemical models to calculate gas solubility, aqueous complexation, reduction/oxidation (redox), and/or mineral solubility reactions related to CO2 injection and sequestration. Thermodynamic data are critical inputs to modeling geochemical processes. The adequacy of thermodynamic data for carbonate compounds has been identified as an important data requirement for the successful application of these geochemical reaction models to CO2 sequestration. A review of thermodynamic data for CO2 gas and carbonate aqueous species and minerals present in published data compilations and databases used in geochemical reaction models was therefore completed. Published studies that describe mineralogical analyses from CO2 sequestration field and natural analogue sites and laboratory studies were also reviewed to identify specific carbonate minerals that are important to CO2 sequestration reactions and therefore require thermodynamic data. The results of the literature review indicated that an extensive thermodynamic database exists for CO2 and CH4 gases, carbonate aqueous species, and carbonate minerals. Values of ?fG298 and/or log Kr,298 are available for essentially all of these compounds. However, log Kr,T or heat capacity values at temperatures above 298 K exist for less than approximately one-third of these compounds. Because the temperatures of host formations that will be used for CO2 injection and sequestration will be at temperatures in the range of 50C to 100C or greater, the lack of high temperature thermodynamic values for key carbonate compounds especially minerals, will impact the accuracy of some modeling calculations.

  19. 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

  20. Effective Transport Properties Accounting for Electrochemical Reactions of Proton-Exchange Membrane Fuel Cell Catalyst Layers

    SciTech Connect (OSTI)

    Pharoah, Jon; Choi, Hae-Won; Chueh, Chih-Che; Harvey, David

    2011-07-01T23:59:59.000Z

    There has been a rapidly growing interest in three-dimensional micro-structural reconstruction of fuel cell electrodes so as to derive more accurate descriptors of the pertinent geometric and effective transport properties. Due to the limited accessibility of experiments based reconstruction techniques, such as dual-beam focused ion beam-scanning electro microscopy or micro X-Ray computed tomography, within sample micro-structures of the catalyst layers in polymer electrolyte membrane fuel cells (PEMFCs), a particle based numerical model is used in this study to reconstruct sample microstructure of the catalyst layers in PEMFCs. Then the reconstructed sample structure is converted into the computational grid using body-fitted/cut-cell based unstructured meshing technique. Finally, finite volume methods (FVM) are applied to calculate effective properties on computational sample domains.

  1. The Influence of Equilibrium Reactions on the Kinetics of Calcite Dissolution in Lactic Acid Solutions

    E-Print Network [OSTI]

    Shedd, Daniel C

    2014-08-07T23:59:59.000Z

    acid and calcite will allow for optimized treatment design. The kinetic model was also used to isolate the contributions of the transport of reactants, the surface reaction, and the transport of products to the overall resistance of the reaction...

  2. Mechanical reaction-diffusion model for bacterial population dynamics

    E-Print Network [OSTI]

    Ngamsaad, Waipot

    2015-01-01T23:59:59.000Z

    The effect of mechanical interaction between cells on the spreading of bacterial population was investigated in one-dimensional space. A nonlinear reaction-diffusion equation has been formulated as a model for this dynamics. In this model, the bacterial cells are treated as the rod-like particles that interact, when contacting each other, through the hard-core repulsion. The repulsion introduces the exclusion process that causes the fast diffusion in bacterial population at high density. The propagation of the bacterial density as the traveling wave front in long time behavior has been analyzed. The analytical result reveals that the front speed is enhanced by the exclusion process---and its value depends on the packing fraction of cell. The numerical solutions of the model have been solved to confirm this prediction.

  3. Boltzmann-Langevin transport model for heavy-ion collisions

    SciTech Connect (OSTI)

    Ayik, S. [Tennessee Technological Univ., Cookeville, TN (United States)]|[Joint Institute for Heavy-Ion Research, Oak Ridge, TN (United States)

    1994-06-01T23:59:59.000Z

    Heavy-ion collisions at intermediate energies exhibit catastrophic phenomena which requires descriptions based on stochastic transport models. First, the Boltzmann-Langevin model, which provides an example of such stochastic approaches, is briefly described. Then, a projection method for obtaining numerical solutions of the Boltzmann-Langevin equation is discussed. Finally, some applications of the model to heavy-ion collisions are presented.

  4. 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.

  5. Role of chemical reactions of arylamine hole transport materials in operational degradation of organic light-emitting diodes

    SciTech Connect (OSTI)

    Kondakov, Denis Y. [Eastman Kodak Company, Rochester, New York 14650-2103 (United States)

    2008-10-15T23:59:59.000Z

    We report that the representative arylamine hole transport materials undergo chemical transformations in operating organic light-emitting diode (OLED) devices. Although the underlying chemical mechanisms are too complex to be completely elucidated, structures of several identified degradation products point at dissociations of relatively weak carbon-nitrogen and carbon-carbon bonds in arylamine molecules as the initiating step. Considering the photochemical reactivities, the bond dissociation reactions of arylamines occur by the homolysis of the lowest singlet excited states formed by recombining charge carriers in the operating OLED device. The subsequent chemical reactions are likely to yield long-lived, stabilized free radicals capable of acting as deep traps--nonradiative recombination centers and fluorescence quenchers. Their presence in the hole transport layer results in irreversible hole trapping and manifests as a positive fixed charge. The extent and localization of chemical transformations in several exemplary devices suggest that the free radical reactions of hole transporting materials, arylamines, can be sufficient to account for the observed luminance efficiency loss and voltage rise in operating OLEDs. The relative bond strengths and excited state energies of OLED materials appear to have a determining effect on the operational stability of OLED devices.

  6. Mass transfer model for two-layer TBP oxidation reactions

    SciTech Connect (OSTI)

    Laurinat, J.E.

    1994-09-28T23:59:59.000Z

    To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. This report presents measurements of mass transfer rates for the mixing of water and butanol in two-layer, TBP-aqueous mixtures, where the top layer is primarily TBP and the bottom layer is comprised of water or aqueous salt solution. Mass transfer coefficients are derived for use in the modeling of two-layer TBP-nitric acid oxidation experiments. Three cases were investigated: (1) transfer of water into the TBP layer with sparging of both the aqueous and TBP layers, (2) transfer of water into the TBP layer with sparging of just the TBP layer, and (3) transfer of butanol into the aqueous layer with sparging of both layers. The TBP layer was comprised of 99% pure TBP (spiked with butanol for the butanol transfer experiments), and the aqueous layer was comprised of either water or an aluminum nitrate solution. The liquid layers were air sparged to simulate the mixing due to the evolution of gases generated by oxidation reactions. A plastic tube and a glass frit sparger were used to provide different size bubbles. Rates of mass transfer were measured using infrared spectrophotometers provided by SRTC/Analytical Development.

  7. 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...

  8. Global Transportation Roadmap Model | Open Energy Information

    Open Energy Info (EERE)

    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 Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to: navigation,GigaCreteInformation| Open EnergyTransportation

  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. 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

  11. 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

  12. 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

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

    E-Print Network [OSTI]

    -dimensional reactive transport modeling of carbon tetrachloride (CT) bioremediation at the Schoolcraft site in western

  14. An Equilibrium-Based Model of Gas Reaction and Detonation

    SciTech Connect (OSTI)

    Trowbridge, L.D.

    2000-04-01T23:59:59.000Z

    During gaseous diffusion plant operations, conditions leading to the formation of flammable gas mixtures may occasionally arise. Currently, these could consist of the evaporative coolant CFC-114 and fluorinating agents such as F2 and ClF3. Replacement of CFC-114 with a non-ozone-depleting substitute is planned. Consequently, in the future, the substitute coolant must also be considered as a potential fuel in flammable gas mixtures. Two questions of practical interest arise: (1) can a particular mixture sustain and propagate a flame if ignited, and (2) what is the maximum pressure that can be generated by the burning (and possibly exploding) gas mixture, should it ignite? Experimental data on these systems, particularly for the newer coolant candidates, are limited. To assist in answering these questions, a mathematical model was developed to serve as a tool for predicting the potential detonation pressures and for estimating the composition limits of flammability for these systems based on empirical correlations between gas mixture thermodynamics and flammability for known systems. The present model uses the thermodynamic equilibrium to determine the reaction endpoint of a reactive gas mixture and uses detonation theory to estimate an upper bound to the pressure that could be generated upon ignition. The model described and documented in this report is an extended version of related models developed in 1992 and 1999.

  15. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    SciTech Connect (OSTI)

    Yorstos, Yannis C.

    2003-03-19T23:59:59.000Z

    The report describes progress made in the various thrust areas of the project, which include internal drives for oil recovery, vapor-liquid flows, combustion and reaction processes and the flow of fluids with yield stress.

  16. Comprehensive model to determine the effects of temperature and species fluctuations on reaction rates in turbulent reaction flows

    SciTech Connect (OSTI)

    Magnotti, F.; Diskin, G.; Matulaitis, J.; Chinitz, W.

    1984-01-01T23:59:59.000Z

    The use of silane (SiH4) as an effective ignitor and flame stabilizing pilot fuel is well documented. A reliable chemical kinetic mechanism for prediction of its behavior at the conditions encountered in the combustor of a SCRAMJET engine was calculated. The effects of hydrogen addition on hydrocarbon ignition and flame stabilization as a means for reduction of lengthy ignition delays and reaction times were studied. The ranges of applicability of chemical kinetic models of hydrogen-air combustors were also investigated. The CHARNAL computer code was applied to the turbulent reaction rate modeling.

  17. 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

  18. 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

  19. Chemical reaction model for oil and gas generation from type 1 and type 2 kerogen

    SciTech Connect (OSTI)

    Braun, R.L.; Burnham, A.K.

    1993-06-01T23:59:59.000Z

    A global model for the generation of oil and gas from petroleum source rocks is presented. The model consists of 13 chemical species and 10 reactions, including an alternate-pathway mechanism for kerogen pyrolysis. Reaction rate parameters and stoichiometry coefficients determined from a variety of pyrolysis data are given for both type I and type II kerogen. Use of the chemical reaction model is illustrated for typical geologic conditions.

  20. 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

  1. Targeted Observations for Atmospheric Chemistry and Transport Models

    E-Print Network [OSTI]

    Sandu, Adrian

    for a simulation of atmospheric pollution in East Asia in March 2001 show that the optimal location of observations, targeted observations. 1 Introduction Our ability to anticipate and manage changes in atmospheric pollutantTargeted Observations for Atmospheric Chemistry and Transport Models Adrian Sandu Department

  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. A Microscopic Traffic Simulation Model for Transportation Planning in Georgios Papageorgiou, Pantelis Damianou, Andreas Pitsilides

    E-Print Network [OSTI]

    Pitsillides, Andreas

    A Microscopic Traffic Simulation Model for Transportation Planning in Cyprus Georgios Papageorgiou. This paper presents the microscopic simulation model development of a major traffic network of Nicosia simulation model is developed and utilized for transportation planning. 1. Introduction The demand

  4. Analytical model for flux saturation in sediment transport

    E-Print Network [OSTI]

    T. Phtz; E. J. R. Parteli; J. F. Kok; H. J. Herrmann

    2014-05-30T23:59:59.000Z

    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 entrainment prevailing under different environmental conditions. Our analytical treatment allows us to derive a closed expression for the saturation length of sediment flux, which is general and can thus be applied under different physical conditions.

  5. 3D Field-Scale Reactive Transport Modeling of In Situ Immobilization of Uranium in Structured Porous Media via Biostimulation

    SciTech Connect (OSTI)

    Fang, Yilin; Scheibe, Timothy D.; Roden, Eirc E.; Kamolpornwijit, Wiwat; Brooks, Scott C.

    2006-09-12T23:59:59.000Z

    A several-month-long ethanol injection experiment is being conducted to study the impacts of porous media structure (i.e., heterogeneity existing at multiple scales) on the effectiveness of metal/radionuclide bioremediation in a highly heterogeneous unconfined aquifer near Oak Ridge, TN, USA. We have constructed a 3D field-scale groundwater flow and multicomponent reactive transport model to simulate the experimental observations. The model incorporates a suite of abiotic reactions and microbially-mediated redox reactions for multiple terminal electron accepting processes (TEAPs) including soluble oxygen, nitrate, U(VI) and sulfate and solid-phase electron acceptors. Different biomass populations are considered in the model. Growth of these populations is derived from the bioenergetics-based approach in which the partitioning of electron flow between energy generation and cell biomass production is dependent on the free energy of the corresponding TEAP. TEAP reaction rates were free energy constrained. The TEAP model and reaction system have been formulated and used to simulate laboratory batch experimental observations. We conducted the field-scale simulation starting with the reaction system and parameters obtained from the batch experiment and hydrologic parameters estimated from the results of pumping tests, water level monitoring and model interpretation of a tracer test conducted in August 2004. Reaction parameters were investigated to compare simulation results and field experiment observations.

  6. 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.

  7. 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.

  8. 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.

  9. Nuclear reaction analysis profiling as direct evidence for lithium ion mass transport in thin film rocking-chair'' structures

    SciTech Connect (OSTI)

    Goldner, R.B.; Haas, T.E.; Arntz, F.O.; Slaven, S.; Wong, K.K. (Electro-Optics Technology Center, Tufts University, Medford, Massachusetts 02155 (United States)); Wilkens, B. (Bellcore, Red Bank, New Jersey 07001-7040 (United States)); Shepard, C.; Lanford, W. (Accelerator Laboratory, Physics Department, State University of New York at Albany, Albany, New York 12222 (United States))

    1993-04-05T23:59:59.000Z

    A nuclear reaction analysis technique using the [ital p],[gamma] reaction, [sup 7]Li([ital p],[gamma])[sup 8]Be, occurring at approximately 440 keV, (half-width[approx]12 keV), has been utilized to determine the lithium concentration profiles in multilayer electrochromic window ( smart window'')/rechargeable battery cells when in their colored''/charged and bleached''/discharged states. The lithium profiles have been observed to shift according to the cells' states, thereby providing direct experimental evidence for the so-called rocking-chair model for such structures.

  10. Advancements in the ADAPT Photospheric Flux Transport Model

    E-Print Network [OSTI]

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

    2014-10-22T23:59:59.000Z

    Maps of the solar photospheric magnetic flux are fundamental drivers for simulations of the corona and solar wind which makes photospheric simulations important predictors of solar events on Earth. However, observations of the solar photosphere are only made intermittently over small regions 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 ADAPT model and the implementation of the LETKF. Advantages of the LETKF scheme over previously implemented assimilation methods are highlighted.

  11. MELTING OF GLASS BATCH - MODEL FOR MULTIPLE OVERLAPPING GAS-EVOLVING REACTIONS

    SciTech Connect (OSTI)

    KRUGER AA; PIERCE DA; POKORNY R; HRMA PR

    2012-02-07T23:59:59.000Z

    In this study, we present a model for the kinetics of multiple overlapping reactions. Mathematical representation of the kinetics of gas-evolving reactions is crucial for the modeling of the feed-to-glass conversion in a waste-glass melter. The model simulates multiple gas-evolving reactions that occur during heating of a high-alumina high-level waste melter feed. To obtain satisfactory kinetic parameters, we employed Kissinger's method combined with least-squares analysis. The power-law kinetics with variable reaction order sufficed for obtaining excellent agreement with measured thermogravimetric analysis data.

  12. Microfluidic Technology Platforms for Synthesizing, Labeling and Measuring the Kinetics of Transport and Biochemical Reactions for Developing Molecular Imaging Probes

    SciTech Connect (OSTI)

    Phelps, Michael E.

    2009-09-01T23:59:59.000Z

    Radiotracer techniques are used in environmental sciences, geology, biology and medicine. Radiotracers with Positron Emission Tomography (PET) provided biological examinations of ~3 million patients 2008. Despite the success of positron labeled tracers in many sciences, there is limited access in an affordable and convenient manner to develop and use new tracers. Integrated microfluidic chips are a new technology well matched to the concentrations of tracers. Our goal is to develop microfluidic chips and new synthesis approaches to enable wide dissemination of diverse types of tracers at low cost, and to produce new generations of radiochemists for which there are many unfilled jobs. The program objectives are to: 1. Develop an integrated microfluidic platform technology for synthesizing and 18F-labeling diverse arrays of different classes of molecules. 2. Incorporate microfluidic chips into small PC controlled devices (Synthesizer) with a platform interfaced to PC for electronic and fluid input/out control. 3. Establish a de-centralized model with Synthesizers for discovering and producing molecular imaging probes, only requiring delivery of inexpensive [18F]fluoride ion from commercial PET radiopharmacies vs the centralized approach of cyclotron facilities synthesizing and shipping a few different types of 18F-probes. 4. Develop a position sensitive avalanche photo diode (PSAPD) camera for beta particles embedded in a microfluidic chip for imaging and measuring transport and biochemical reaction rates to valid new 18F-labeled probes in an array of cell cultures. These objectives are met within a research and educational program integrating radio-chemistry, synthetic chemistry, biochemistry, engineering and biology in the Crump Institute for Molecular Imaging. The Radiochemistry Training Program exposes PhD and post doctoral students to molecular imaging in vitro in cells and microorganisms in microfluidic chips and in vivo with PET, from new technologies for radiochemistry (macro to micro levels), biochemistry and biology to imaging principles, tracer kinetics, pharmacokinetics and biochemical assays. New generations of radiochemists will be immersed in the biochemistry and biology for which their labeled probes are being developed for assays of these processes. In this program engineers and radio-chemists integrate the principles of microfluidics and radiolabeling along with proper system design and chemistry rule sets to yield Synthesizers enabling biological and pharmaceutical scientists to develop diverse arrays of probes to pursue their interests. This progression would allow also radiochemists to focus on the further evolution of rapid, high yield synthetic reactions with new enabling technologies, rather than everyday production of radiotracers that should be done by technologists. The invention of integrated circuits in electronics established a platform technology that allowed an evolution of ideas and applications far beyond what could have been imagined at the beginning. Rather than provide a technology for the solution to a single problem, it is hoped that microfluidic radiochemistry will be an enabling platform technology for others to solve many problems. As part of this objective, another program goal is to commercialize the technologies that come from this work so that they can be provided to others who wish to use it.

  13. 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.

  14. Iron Reduction and Radionuclide Immobilization: Kinetic, Thermodynamic and Hydrologic controls & Reaction-Based Modeling - Final Report

    SciTech Connect (OSTI)

    William D. Burgos

    2004-06-18T23:59:59.000Z

    Our research focused on (1) microbial reduction of Fe(III) and U(VI) individually, and concomitantly in natural sediments, (2) Fe(III) oxide surface chemistry, specifically with respect to reactions with Fe(II)and U(VI), (3) the influence of humic substances on Fe(III) and U(VI) bioreduction, and on U(VI) complexation, and (4) the development of reaction-based reactive transport biogeochemical models to numerically simulate our experimental results. We have continued our investigations on microbial reduction of Fe(III) oxides. Modeling our earlier experimental results required assumption of a hydrated surface for hematite, more reactive than predicted based on theoretical solubility (Burgos et al.2002). Subsequent studies with Shewanella putrefaciens and Geobacter sulfurreducens confirmed the rates of Fe(III) bioreduction depend on oxide surface area rather than oxide thermodynamic properties (Roden,2003a,b;2004; Burgos et al,2003). We examined the potential for bioreduction of U(VI) by Geobacter sulfurreducens in the presence of synthetic Fe(III) oxides and natural Fe(III) oxide-containing solids (Jeon et al,2004a,b) in which more than 95% of added U(VI) was sorbed to mineral surfaces. The results showed a significant portion of solid-associated U(VI) was resistant to both enzymatic and abiotic (Fe(II)-driven) reduction, but the rate and extent of bioreduction of U(VI) was increased due to the addition of anthraquinone-2,6-disulfonate (AQDS). We conducted long-term semicontinuous culture and column experiments on coupled Fe(III) oxide/U(VI) reduction. These experiments were conducted with natural subsurface sediment from the Oyster site in Virginia, whose Fe content and microbial reducibility are comparable to ORNL FRC sediments (Jeon et al, 2004b). The results conclusively demonstrated the potential for sustained removal of U(VI) from solution via DMRB activity in excess of the U(VI) sorption capacity of the natural mineral assemblages. Jang (2004) demonstrated that the hydrated surface of nano-particles of hematite (prepared according to well-cited recipes and confirmed to be 100% hematite by Mossbauer spectroscopy and XRD) exhibited the solubility of hydrous ferric oxide (HFO). Jang (2004) also demonstrated that the sorptive reactivity of hematite and HFO were identical except for different specific surface area and pHzpc, and that the reduction of U(VI) by sorbed Fe(II) in the presence of the two phases was also similar in spite of theoretical predictions of large differences in Nernst potential. These results are consistent with the modeling of hematite bioreduction experiments where the thermodynamic potential of hematite had to be adjusted to represent a more disordered surface phase in order to accurately model bioreduction kinetics (Burgos et al, 2002, 2003). We have demonstrated that humic substances enhance solid-phase Fe(III) bioreduction via both electron shuttling and Fe(II) complexation(Royer et al, 2002a, b). We have found that humic substances were shown to inhibit the bioreduction of dissolved U(VI) and that soluble humic-U(IV) complexes were likely formed (Burgos et al, 2004). Kirkham (2004) measured and modeled complexation of U(VI) by humic substances as a function of pH, pCO2, U(VI) concentration, and humic concentration, and demonstrated that humic substances can complex U(VI) even at neutral pH values and in the presence of high (ca.30 mM) carbonate concentrations. Jang(2004) measured the abiotic reduction of U(VI) by Fe(II) sorbed to Fe(III) oxides in the presence/absence of humic substances and demonstrated that humic substances inhibited the heterogeneous reduction of U(VI). We have recently developed, validated, and documented a series of diagonalized reaction-based reactive transport computer models (HYDROGEOCHEM; Yeh et al,2004a,b). We demonstrated that parallel kinetic reactions could be modeled if separate experiments are used to independently measure each contributing kinetic reaction (Burgos et al, 2003). We have demonstrated the use of a reaction-based reactive transport model (HYDROGE

  15. Log-domain circuit models of chemical reactions

    E-Print Network [OSTI]

    Mandal, Soumyajit

    We exploit the detailed similarities between electronics and chemistry to develop efficient, scalable bipolar or subthreshold log-domain circuits that are dynamically equivalent to networks of chemical reactions. Our ...

  16. Kinetic Modeling Of Solid-Gas Reactions At Reactor Scale: A General Approach Loc Favergeon1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    the knowledge of the kinetic model for the calculation of the speed of reaction in one part of the reactorKinetic Modeling Of Solid-Gas Reactions At Reactor Scale: A General Approach Loïc Favergeon1 favergeon@emse.fr ABSTRACT A rigorous simulation of industrial reactors in the case of solid-gas reacting

  17. 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.

  18. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    SciTech Connect (OSTI)

    Yortsos, Yanis C.

    2002-10-08T23:59:59.000Z

    In this report, the thrust areas include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  19. 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

  20. Engineered Barrier System Degradation, Flow, and Transport Process Model Report

    SciTech Connect (OSTI)

    E.L. Hardin

    2000-07-17T23:59:59.000Z

    The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).

  1. Cold-cap reactions in vitrification of nuclear waste glass: experiments and modeling

    SciTech Connect (OSTI)

    Chun, Jaehun [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pierce, David A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pokorny, Richard [Inst. of Chemical Technology, Prague (Czech Republic); Hrma, Pavel R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pohang Univ. of Science and Techology (Korea, Republic of)

    2013-05-10T23:59:59.000Z

    Cold-cap reactions are multiple overlapping reactions that occur in the waste-glass melter during the vitrification process when the melter feed is being converted to molten glass. In this study, we used differential scanning calorimetry (DSC) to investigate cold-cap reactions in a high-alumina high-level waste melter feed. To separate the reaction heat from both sensible heat and experimental instability, we employed the run/rerun method, which enabled us to define the degree of conversion based on the reaction heat and to estimate the heat capacity of the reacting feed. Assuming that the reactions are nearly independent and can be approximated by the nth order kinetics, we obtained the kinetic parameters using the Kissinger method combined with least squares analysis. The resulting mathematical simulation of the cold-cap reactions provides a key element for the development of an advanced cold-cap model.

  2. 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.

  3. 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.

  4. Folding model description of reactions with exotic nuclei

    SciTech Connect (OSTI)

    Ibraheem, Awad A., E-mail: awad_ah_eb@hotmail.com [Al-Azhar University, Assiut Branch, Physics Department (Egypt); Hassanain, M. A. [King Khalid University, Physics Department (Saudi Arabia); Mokhtar, S. R. [Assiut University, Physics Department (Egypt); Zaki, M. A. [South-Valley University, Physics Department (Egypt); Mahmoud, Zakaria M. M. [Assiut University, Sciences Department, New-Valley Faculty of Education (Egypt); Farid, M. El-Azab [Assiut University, Physics Department (Egypt)

    2012-08-15T23:59:59.000Z

    Microscopic folding calculations based upon the effective M3Y nucleon-nucleon interaction and the nuclearmatter densities of the interacting nuclei have been carried out to explain recently measured experimental data of the {sup 6}He+{sup 120}Sn elastic scattering cross section at four different laboratory energies near the Coulomb barrier. The extracted reaction cross sections are also considered.

  5. 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 electrical discharges using equivalent species transport Fred Y. Huanga) and Mark J. Kushnerb) Departm&t of Electrical and Computer Engineering, University of Illinois, 1406 West Green Street, Urbana, Illinois 61801

  6. 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.

  7. Application of a new screening model to thermonuclear reactions of the rp process

    E-Print Network [OSTI]

    Theodore Liolios

    2003-05-09T23:59:59.000Z

    A new screening model for astrophysical thermonuclear reactions was derived recently which improved Salpeter's weak-screening one. In the present work we prove that the new model can also give very reliable screening enhancement factors (SEFs) when applied to the rp process. According to the results of the new model, which agree well with Mitler's SEFs, the screened rp reaction rates can be, at most, twice as fast as the unscreened ones.

  8. 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 ...

  9. A minimum-reaction-flux solution to master-equation models of protein folding

    E-Print Network [OSTI]

    Weston, Ken

    A minimum-reaction-flux solution to master-equation models of protein folding Huan-Xiang Zhoua; published online 20 May 2008 Master equations are widely used for modeling protein folding. Here- ceptual and quantitative models for protein folding.1­15 In such models, the conformational space

  10. Analysis of the energy transport and deposition within the reaction chamber of the prometheus inertial fusion energy reactor

    SciTech Connect (OSTI)

    Eggleston, J.E.; Abdou, M.A.; Tillack, M.S. [Univ. of California, Los Angeles, CA (United States)

    1994-12-31T23:59:59.000Z

    One of the parameters affecting the feasibility of Inertial Fusion Energy (IFE) devices is the number of shots per unit time, i.e. the repetition rate. The repetition rate limits the achievable power that can be obtained from the reactor. To obtain an estimate of the allowable time between shots, a code named RECON was developed to model the response of the reaction chamber to the pellet explosion. This paper discusses how the code treats the thermodynamic response of the cavity gas and models the condensation/evaporation of this vapor to and from the first wall. A large amount of energy from the pellet microexplosion is carried by the pellet debris and the x-rays generated in the fusion reaction. Models of x-ray attenuation and ion slowing down are used to estimate the fraction of the pellet energy that is absorbed in the vapor. A large amount of energy is absorbed into the cavity gas, which causes it to become partially ionized. The ionization complicates the calculation of the temperature, pressure, and the radiative heat transfer from the gas to the first wall. To treat this problem, methods developed by Zel`dovich and Raizer are used in modeling the internal energy and the radiative heat flux. RECON was developed to run with a relatively short computational time, yet accurate enough for conceptual reactor design calculations.

  11. Well-posedness of a moving two-reaction-strips problem modeling

    E-Print Network [OSTI]

    Eindhoven, Technische Universiteit

    CO2 in unsaturated cement-based porous materials (concrete). The main issue is that CO2 diffusionWell-posedness of a moving two-reaction-strips problem modeling chemical corrosion of porous media and fast reaction with Ca(OH)2 in concrete lead to a sudden drop of alkalinity near the steel reinforcement

  12. Modelling proton-induced reactions at low energies in the MARS15 code

    E-Print Network [OSTI]

    Rakhno, Igor L; Gudima, Konstantin K

    2015-01-01T23:59:59.000Z

    An implementation of both the ALICE code and TENDL evaluated nuclear data library in order to describe nuclear reactions by low-energy projectiles in the Monte Carlo code MARS15 is presented. Comparisons between results of modelling and experimental data on reaction cross sections and secondary particle distributions are shown as well.

  13. 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.

  14. 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.

  15. 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]).

  16. 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-three-dimensional suspended sediment transport model was developed and generalized to include combined wave-current effects to study bottom sediment resuspension and transport in southern Lake Michigan. The results from a three

  17. 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.

  18. Cahn-Hilliard Reaction Model for Isotropic Li-ion Battery Particles

    E-Print Network [OSTI]

    Zeng, Yi

    Using the recently developed Cahn-Hilliard reaction (CHR) theory, we present a simple mathematical model of the transition from solid-solution radial diffusion to two-phase shrinking-core dynamics during ion intercalation ...

  19. 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.

  20. Low energy ($p,?$) reactions in Ni and Cu nuclei using microscopic optical model

    E-Print Network [OSTI]

    G. Gangopadhyay

    2010-08-05T23:59:59.000Z

    Radiative capture reactions for low energy protons have been theoretically studied for Ni and Cu isotopes using the microscopic optical model. The optical potential has been obtained in the folding model using different microscopic interactions with the nuclear densities from Relativistic Mean Field calculations. The calculated total cross sections as well as the cross sections for individually low lying levels have been compared with measurements involving stable nuclear targets. Rates for the rapid proton capture process have been evaluated for astrophysically important reactions.

  1. Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region

    SciTech Connect (OSTI)

    T.-S. H. Lee; A. Matsuyama; T. Sato

    2006-11-15T23:59:59.000Z

    A dynamical coupled-channel model is presented for investigating the nucleon resonances (N*) in the meson production reactions induced by pions and photons. Our objective is to extract the N* parameters and to investigate the meson production reaction mechanisms for mapping out the quark-gluon substructure of N* from the data. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method.

  2. A comparative study of vibrational relaxation and chemical reaction models for the Martian entry vehicle

    E-Print Network [OSTI]

    Koteshwar, Rajeev

    1992-01-01T23:59:59.000Z

    A COMPARATIVE STUDY OF VIBRATIONAL RELAXATION AND CHEMICAL REACTION MODELS FOR THE MARTIAN ENTRY VEHICLE A Thesis by RAJEEV KOTESHWAR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1992 Major Subject: Aerospace Engineering A COMPARATIVE STUDY OF VIBRATIONAL RELAXATION AND CHEMICAL REACTION MODELS FOR THE MARTIAN ENTRY VEHICLE A Thesis by RAJEEV KOTESHWAR Approved as to style...

  3. 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.

  4. Generalized solution to multi-dimensional multi-species transport equations coupled with a first-order reaction

    E-Print Network [OSTI]

    Clement, Prabhakar

    Generalized solution to multi-dimensional multi-species transport equations coupled with a first-species reactive transport equations. The new method can be used for solving multi-species transport problems transport problem. In addition, three one-dimensional problems and two three-dimensional problems are solved

  5. 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.

  6. Chemical reactions of UF{sub 6} with water on ingress to damaged model 48X 10 ton cylinder

    SciTech Connect (OSTI)

    Rothman, A.B.

    1996-02-01T23:59:59.000Z

    Chemistry studies of the effects of water flooding in Model 48X 10-ton UF{sub 6} storage cylinders, as a result of impact fractures, were conducted to support the Safety Analysis Report for Packaging (SARP) review of the Paducah Tiger Overpack for transportation of those cylinders. The objectives of the study were to determine the maximum amount of water that could be admitted to the interior of such a damaged cylinder, the resulting geometries and chemical compositions from reactions of water with the UF{sub 6} contents of the cylinder, and the end-state water moderated and reflected configurations for input to nuclear criticality safety analyses. The case identified for analysis was the flooding of the inside of a cylinder, submerged horizontally in 3 ft of water. The flooding was driven by an initial pressure drop of 13 psig, through an assumed fracture (1/32 in. wide {times} 1/2 in. deep {times} 18 in. long) in the barrel of the cylinder. During the initial addition of water, transient back pressures occur from the effects of the heats of reaction and solution at the water/UF{sub 6} interface, with some chugging as more water is added to alternately coot the reaction surface and then heat it again as the added water reacts with more UF{sub 6}.

  7. 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.

  8. 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.

  9. Large-Scale Evacuation Network Model for Transporting Evacuees with Multiple Priorities

    E-Print Network [OSTI]

    Na, Hyeong Suk

    2014-05-01T23:59:59.000Z

    mathematical optimization model called Triage-Assignment-Transportation (TAT) model is suggested in order to decide on the tactical routing assignment of several classes of evacuation vehicles between staging areas and shelters in the nearby area. The model...

  10. 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 ...

  11. A Radionuclide Transport Model for the Unsaturated Zone at Yucca Mountain Bruce A. Robinson

    E-Print Network [OSTI]

    Lu, Zhiming

    A Radionuclide Transport Model for the Unsaturated Zone at Yucca Mountain Bruce A. Robinson Zhiming model calculations for radionuclide transport in the unsaturated zone at Yucca Mountain. The model developed by the Yucca Mountain Project based on calibrations to site data. The particle-tracking technique

  12. To appear in the SIGGRAPH conference proceedings A Practical Model for Subsurface Light Transport

    E-Print Network [OSTI]

    Stanford University

    be simulated accurately but slowly by solving the full radiative transfer equation [1]. Only a few papersTo appear in the SIGGRAPH conference proceedings A Practical Model for Subsurface Light Transport introduces a simple model for subsurface light transport in translucent materials. The model enables

  13. A radiation transport coupled particle-in-cell simulation. I. Description of the model

    E-Print Network [OSTI]

    Lee, Hae June

    A radiation transport coupled particle-in-cell simulation. I. Description of the model Hae June-dimensional radiation transport model is coupled with a particle-in-cell simulation in order to incorporate such as ground, radiative, and metastable state atoms are treated with a fluid model combined with the Holstein

  14. 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

  15. 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

  16. 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

  17. 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.

  18. Technical Work Plan for: Near Field Environment: Engineered System: Radionuclide Transport Abstraction Model Report

    SciTech Connect (OSTI)

    J.D. Schreiber

    2006-12-08T23:59:59.000Z

    This technical work plan (TWP) describes work activities to be performed by the Near-Field Environment Team. The objective of the work scope covered by this TWP is to generate Revision 03 of EBS Radionuclide Transport Abstraction, referred to herein as the radionuclide transport abstraction (RTA) report. The RTA report is being revised primarily to address condition reports (CRs), to address issues identified by the Independent Validation Review Team (IVRT), to address the potential impact of transport, aging, and disposal (TAD) canister design on transport models, and to ensure integration with other models that are closely associated with the RTA report and being developed or revised in other analysis/model reports in response to IVRT comments. The RTA report will be developed in accordance with the most current version of LP-SIII.10Q-BSC and will reflect current administrative procedures (LP-3.15Q-BSC, ''Managing Technical Product Inputs''; LP-SIII.2Q-BSC, ''Qualification of Unqualified Data''; etc.), and will develop related Document Input Reference System (DIRS) reports and data qualifications as applicable in accordance with prevailing procedures. The RTA report consists of three models: the engineered barrier system (EBS) flow model, the EBS transport model, and the EBS-unsaturated zone (UZ) interface model. The flux-splitting submodel in the EBS flow model will change, so the EBS flow model will be validated again. The EBS transport model and validation of the model will be substantially revised in Revision 03 of the RTA report, which is the main subject of this TWP. The EBS-UZ interface model may be changed in Revision 03 of the RTA report due to changes in the conceptualization of the UZ transport abstraction model (a particle tracker transport model based on the discrete fracture transfer function will be used instead of the dual-continuum transport model previously used). Validation of the EBS-UZ interface model will be revised to be consistent with model changes.

  19. 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 models ability to simulate PAHs with different volatilities, ...

  20. 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.

  1. 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...

  2. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems

    SciTech Connect (OSTI)

    Contreras, A.M.

    2006-05-20T23:59:59.000Z

    In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

  3. 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 ...

  4. 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

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

    E-Print Network [OSTI]

    Mnster, Westflische Wilhelms-Universitt

    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

  6. 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

  7. Multiscale models of atmospheric mercury: bromine chemistry, air-sea exchange, and global transport

    E-Print Network [OSTI]

    Holmes, Christopher D.

    entrainment of RGM-rich air from the free troposphere (25­40%). Oxidation of Hg0 by Cl is minor (3Multiscale models of atmospheric mercury: bromine chemistry, air-sea exchange, and global transport Multiscale models of atmospheric mercury: bromine chemistry, air-sea exchange, and global transport Abstract

  8. Numerical modeling of interface dynamics and transport phenomena in transport-limited electrolysis processes

    E-Print Network [OSTI]

    Pongsaksawad, Wanida

    2006-01-01T23:59:59.000Z

    Electrochemical reactions in materials and processes induce morphological instability on the cathode, which can lead to porous deposits or system failure. The growth of the protrusion is a complex phenomenon which involves ...

  9. Modelling of silicon oxynitridation by nitrous oxide using the reaction rate approach

    SciTech Connect (OSTI)

    Dominique Krzeminski, Christophe, E-mail: christophe.krzeminski@isen.fr [Dpartment ISEN, IEMN-UMR-8520, 41 Boulevard Vauban, 59046 Lille Cedex (France)

    2013-12-14T23:59:59.000Z

    Large technological progress in oxynitridation processing leads to the introduction of silicon oxynitride as ultra-thin gate oxide. On the theoretical side, few studies have been dedicated to the process modelling of oxynitridation. Such an objective is a considerable challenge regarding the various atomistic mechanisms occurring during this fabrication step. In this article, some progress performed to adapt the reaction rate approach for the modelling of oxynitride growth by a nitrous ambient are reported. The Ellis and Buhrman's approach is used for the gas phase decomposition modelling. Taking into account the mass balance of the species at the interface between the oxynitride and silicon, a minimal kinetic model describing the oxide growth has been calibrated and implemented. The influence of nitrogen on the reaction rate has been introduced in an empirical way. The oxidation kinetics predicted with this minimal model compares well with several experiments.

  10. Transportation

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassiveSubmittedStatusButler TinaContact-Information-Transmission SignTransport

  11. 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.

  12. MODELLING OF CONCRETE STRUCTURES AFFECTED BY INTERNAL SWELLING REACTIONS: COUPLINGS BETWEEN

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Page 1 MODELLING OF CONCRETE STRUCTURES AFFECTED BY INTERNAL SWELLING REACTIONS: COUPLINGS BETWEEN of the affected concrete that generally leads to cracking and decrease of its mechanical properties of the concrete works and structural integrity. To manage with considered suffering structures, it is necessary

  13. Modeling spatiotemporal behavior of the NO+CO reaction on Pt

    SciTech Connect (OSTI)

    Evans, J.W.; Madden, H.H.; Imbihl, R. (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, W-1000 Berlin 33 (Germany))

    1992-03-15T23:59:59.000Z

    Various features of NO+CO reaction kinetics on Pt(100) surfaces, including temporal oscillations, are well described by a three-variable model incorporating only the CO, NO, and O coverages. Here we analyze the corresponding reaction--diffusion equations demonstrating the existence of chemical waves where an oscillating phase'' displaces an unreactive NO/CO phase leaving a spatially periodic structure in its wake; pulses excited via inhomogeneities from an unreactive NO/CO background; and Turing structures for sufficiently unequal NO and CO diffusion rates.

  14. 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...

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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-

  20. Standing Waves in a Two-Dimensional Reaction-Diffusion Model with the Short-Wave Instability

    E-Print Network [OSTI]

    Epstein, Irving R.

    Standing Waves in a Two-Dimensional Reaction-Diffusion Model with the Short-Wave Instability Milos 25, 1998; In Final Form: October 19, 1998 Various patterns of standing waves are found beyond the onset of the short-wave instability in a model reaction- diffusion system. These include plain

  1. 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

  2. Parallelization of a relaxation scheme modelling the bedload transport of sediments in shallow

    E-Print Network [OSTI]

    Boyer, Edmond

    Parallelization of a relaxation scheme modelling the bedload transport of sediments in shallow the cohesive strength of the soil particles. Once detached, the sediments can be transported downstream as non-cohesive sediment before its deposition. BANG Project, INRIA-Paris-Rocquencourt & LAGA, Universiy Paris 13 Nord

  3. * All figures are in color on the Coastal Sediments Proceedings DVD. NONUNIFORM SEDIMENT TRANSPORT MODELING AT

    E-Print Network [OSTI]

    US Army Corps of Engineers

    1783 * All figures are in color on the Coastal Sediments Proceedings DVD. NONUNIFORM SEDIMENT@ncche.olemiss.edu. Abstract: A depth-averaged two-dimensionalnonuniform sediment transport model is applied to the beaches. The sediment transport, bed change and sorting equations are solved simultaneously and implicitly at the same

  4. 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

  5. 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

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

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    Multicomponent reactive transport modeling at the Ratones uranium mine, Cáceres (Spain) Modelación management. The Ratones uranium mine was abandoned and flooded in 1974. Due to its reducing underground water, uranium, reactive transport, granite hydrochemistry, Ratones mine. Resumen La inundación de minas

  7. ANALYSIS OF MODELS FOR QUANTUM TRANSPORT OF ELECTRONS IN GRAPHENE LAYERS

    E-Print Network [OSTI]

    Méhats, Florian

    ANALYSIS OF MODELS FOR QUANTUM TRANSPORT OF ELECTRONS IN GRAPHENE LAYERS RAYMOND EL HAJJ transport of electrons in a graphene layer. We treat two situations. First, when the particles can move by a selfconsistent po- tential, which is the trace in the plane of the graphene of the 3D Poisson potential

  8. A Semi-Empirical Two Step Carbon Corrosion Reaction Model in PEM Fuel Cells

    SciTech Connect (OSTI)

    Young, Alan; Colbow, Vesna; Harvey, David; Rogers, Erin; Wessel, Silvia

    2013-01-01T23:59:59.000Z

    The cathode CL of a polymer electrolyte membrane fuel cell (PEMFC) was exposed to high potentials, 1.0 to 1.4 V versus a reversible hydrogen electrode (RHE), that are typically encountered during start up/shut down operation. While both platinum dissolution and carbon corrosion occurred, the carbon corrosion effects were isolated and modeled. The presented model separates the carbon corrosion process into two reaction steps; (1) oxidation of the carbon surface to carbon-oxygen groups, and (2) further corrosion of the oxidized surface to carbon dioxide/monoxide. To oxidize and corrode the cathode catalyst carbon support, the CL was subjected to an accelerated stress test cycled the potential from 0.6 VRHE to an upper potential limit (UPL) ranging from 0.9 to 1.4 VRHE at varying dwell times. The reaction rate constants and specific capacitances of carbon and platinum were fitted by evaluating the double layer capacitance (Cdl) trends. Carbon surface oxidation increased the Cdl due to increased specific capacitance for carbon surfaces with carbon-oxygen groups, while the second corrosion reaction decreased the Cdl due to loss of the overall carbon surface area. The first oxidation step differed between carbon types, while both reaction rate constants were found to have a dependency on UPL, temperature, and gas relative humidity.

  9. The Fluid Interface Reactions Structures and Transport (FIRST) EFRC (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    SciTech Connect (OSTI)

    Wesolowski, David J. (Director, FIRST - Fluid Interface Reactions, Structures, and Transport Center) [Director, FIRST - Fluid Interface Reactions, Structures, and Transport Center; FIRST Staff

    2011-05-01T23:59:59.000Z

    'The Fluid Interface Reactions Structures and Transport (FIRST) EFRC' was submitted by FIRST to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. FIRST, an EFRC directed by David J. Wesolowski at the Oak Ridge National Laboratory is a partnership of scientists from nine institutions: Oak Ridge National Laboratory (lead), Argonne National Laboratory, Drexel University, Georgia State University, Northwestern University, Pennsylvania State University, Suffolk University, Vanderbilt University, and University of Virginia. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of Fluid Interface Reactions, Structures and Transport Center is 'to develop quantitative and predictive models of the unique nanoscale environment at fluid-solid interfaces that will enable transformational advances in electrical energy storage and heterogeneous catalysis for solar fuels.' Research topics are: catalysis (biomass, CO{sub 2}, water), electrocatalysis, photocatalysis, photoelectrocatalysis, solar fuels, solar electrodes, electrical energy storage, batteries, capacitors, battery electrodes, electrolytes, extreme environment, CO{sub 2} (convert), greenhouse gas, microelectromechanical systems (MEMS), interfacial characterization, matter by design, novel materials synthesis, and charge transport.

  10. The Fluid Interface Reactions Structures and Transport (FIRST) EFRC (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema (OSTI)

    Wesolowski, David J. (Director, FIRST - Fluid Interface Reactions, Structures, and Transport Center); FIRST Staff

    2011-11-02T23:59:59.000Z

    'The Fluid Interface Reactions Structures and Transport (FIRST) EFRC' was submitted by FIRST to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. FIRST, an EFRC directed by David J. Wesolowski at the Oak Ridge National Laboratory is a partnership of scientists from nine institutions: Oak Ridge National Laboratory (lead), Argonne National Laboratory, Drexel University, Georgia State University, Northwestern University, Pennsylvania State University, Suffolk University, Vanderbilt University, and University of Virginia. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of Fluid Interface Reactions, Structures and Transport Center is 'to develop quantitative and predictive models of the unique nanoscale environment at fluid-solid interfaces that will enable transformational advances in electrical energy storage and heterogeneous catalysis for solar fuels.' Research topics are: catalysis (biomass, CO{sub 2}, water), electrocatalysis, photocatalysis, photoelectrocatalysis, solar fuels, solar electrodes, electrical energy storage, batteries, capacitors, battery electrodes, electrolytes, extreme environment, CO{sub 2} (convert), greenhouse gas, microelectromechanical systems (MEMS), interfacial characterization, matter by design, novel materials synthesis, and charge transport.

  11. Mass transfer model for two-layer TBP oxidation reactions: Revision 1

    SciTech Connect (OSTI)

    Laurinat, J.E.

    1994-11-04T23:59:59.000Z

    To prove that two-layer, TBP-nitric acid mixtures can be safely stored in the Canyon evaporators, it must be demonstrated that a runaway reaction between TBP and nitric acid will not occur. Previous bench-scale experiments showed that, at typical evaporator temperatures, this reaction is endothermic and therefore cannot run away, due to the loss of heat from evaporation of water in the organic layer. However, the reaction would be exothermic and could run away if the small amount of water in the organic layer evaporates before the nitric acid in this layer is consumed by the reaction. Provided that there is enough water in the aqueous layer, this would occur if the organic layer is sufficiently thick so that the rate of loss of water by evaporation exceeds the rate of replenishment due to mixing with the aqueous layer. Bubbles containing reaction products enhance the rate of transfer of water from the aqueous layer to the organic layer. These bubbles are generated by the oxidation of TBP and its reaction products in the organic layer and by the oxidation of butanol in the aqueous layer. Butanol is formed by the hydrolysis of TBP in the organic layer. For aqueous-layer bubbling to occur, butanol must transfer into the aqueous layer. Consequently, the rate of oxidation and bubble generation in the aqueous layer strongly depends on the rate of transfer of butanol from the organic to the aqueous layer. This report presents measurements of mass transfer rates for the mixing of water and butanol in two-layer, TBP-aqueous mixtures, where the top layer is primarily TBP and the bottom layer is comprised of water or aqueous salt solution. Mass transfer coefficients are derived for use in the modeling of two-layer TBP-nitric acid oxidation experiments.

  12. Reaction of nitric oxide with heme proteins and model compounds of hemoglobin

    SciTech Connect (OSTI)

    Sharma, V.S.; Traylor, T.G.; Gardiner, R.; Mizukami, H.

    1987-06-30T23:59:59.000Z

    Rates for the reaction of nitric oxide with several ferric heme proteins and model compounds have been measured. The NO combination rates are markedly affected by the presence or absence of distal histidine. Elephant myoglobin in which the E7 distal histidine has been replaced by glutamine reacts with NO 500-1000 times faster than do the native hemoglobins or myoglobins. By contrast, there is not difference in the CO combination rate constants of sperm whale and elephant myoglobins. Studies on ferric model compounds for the R and T states of hemoglobin indicate that their NO combination rate constants are similar to those observed for the combination of CO with the corresponding ferro derivatives. The last observation suggests that the presence of an axial water molecule at the ligand binding site of ferric hemoglobin A prevents it from exhibiting significant cooperativity in its reactions with NO.

  13. 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 ...

  14. E-Print Network 3.0 - agent transport modeling Sample Search...

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

    results for: agent transport modeling Page: << < 1 2 3 4 5 > >> 1 Lecture Notes in Computer Science 1 Internet Agents for Effective Collaboration Summary: we present WAPM, a Web...

  15. 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 ...

  16. Observations and modeling of wave-acceleration-induced sediment transport in the surfzone

    E-Print Network [OSTI]

    Hoefel, Fernanda Gemael, 1973-

    2004-01-01T23:59:59.000Z

    Onshore sediment transport and sandbar migration are important to the morphological evolution of beaches, but are not understood well. Here, a new model that accounts for accelerations of wave-orbital velocities predicts ...

  17. 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, ...

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

    E-Print Network [OSTI]

    Zheng, L.

    2011-01-01T23:59:59.000Z

    interest in subcritical (hot/liquid) water from 298 K to 473subcritical region. Modeling Studies on the Transport of Benzene and H 2 S in CO 2 -Water

  19. Mathematical Geology, Vol. 33, No. 1, 2001 Modeling Uranium Transport in Koongarra,

    E-Print Network [OSTI]

    Hassanizadeh, S. Majid

    Mathematical Geology, Vol. 33, No. 1, 2001 Modeling Uranium Transport in Koongarra, Australia waste disposal safety assessment studies. The Koongarra uranium deposit in the Alligator Rivers region weathering over several million years, during which many climatological, hydrological, and geological changes

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

    E-Print Network [OSTI]

    Polly, David

    attenuation at a mill tailings site Chen Zhu* Department of Geology and Planetary Science, University)-based transport model. The study site is a contaminated groundwater aquifer underneath a uranium mill tailings

  1. Development of a Proteoliposome Model to Probe Transmembrane Electron-Transfer Reactions

    SciTech Connect (OSTI)

    White, Gaye F.; Shi, Zhi; Shi, Liang; Dohnalkova, Alice; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.; Clarke, Thomas

    2012-12-01T23:59:59.000Z

    The mineral respiring bacterium Shewanella oneidensis uses a protein complex, MtrCAB, composed of two decaheme cytochromes brought together inside a transmembrane porin to transport electrons across the outer membrane to a variety of mineral-based electron acceptors. A proteoliposome system has been developed that contains methyl viologen (MV) as an internalised electron acceptor and valinomycin (V) as a membrane associated cation exchanger. These proteoliposomes can be used as a model system to investigate MtrCAB function.

  2. 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.

  3. Comparisons Between Different Forward Models For Light Transport In Tissues

    E-Print Network [OSTI]

    Guo, Zhixiong "James"

    The radiative transfer equation to describe the laser radiation transport in scattering, absorbing and emitting the radiative heat transfer equation, which can be applied to almost all the electromagnetic radiation. The diffusion approximation method is controlled by a differential equation, which is derived from radiative

  4. 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

  5. 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

  6. KINETIC MODELING OF A FISCHER-TROPSCH REACTION OVER A COBALT CATALYST IN A SLURRY BUBBLE COLUMN REACTOR FOR INCORPORATION INTO A COMPUTATIONAL MULTIPHASE FLUID DYNAMICS MODEL

    SciTech Connect (OSTI)

    Anastasia Gribik; Doona Guillen, PhD; Daniel Ginosar, PhD

    2008-09-01T23:59:59.000Z

    Currently multi-tubular fixed bed reactors, fluidized bed reactors, and slurry bubble column reactors (SBCRs) are used in commercial Fischer Tropsch (FT) synthesis. There are a number of advantages of the SBCR compared to fixed and fluidized bed reactors. The main advantage of the SBCR is that temperature control and heat recovery are more easily achieved. The SBCR is a multiphase chemical reactor where a synthesis gas, comprised mainly of H2 and CO, is bubbled through a liquid hydrocarbon wax containing solid catalyst particles to produce specialty chemicals, lubricants, or fuels. The FT synthesis reaction is the polymerization of methylene groups [-(CH2)-] forming mainly linear alkanes and alkenes, ranging from methane to high molecular weight waxes. The Idaho National Laboratory is developing a computational multiphase fluid dynamics (CMFD) model of the FT process in a SBCR. This paper discusses the incorporation of absorption and reaction kinetics into the current hydrodynamic model. A phased approach for incorporation of the reaction kinetics into a CMFD model is presented here. Initially, a simple kinetic model is coupled to the hydrodynamic model, with increasing levels of complexity added in stages. The first phase of the model includes incorporation of the absorption of gas species from both large and small bubbles into the bulk liquid phase. The driving force for the gas across the gas liquid interface into the bulk liquid is dependent upon the interfacial gas concentration in both small and large bubbles. However, because it is difficult to measure the concentration at the gas-liquid interface, coefficients for convective mass transfer have been developed for the overall driving force between the bulk concentrations in the gas and liquid phases. It is assumed that there are no temperature effects from mass transfer of the gas phases to the bulk liquid phase, since there are only small amounts of dissolved gas in the liquid phase. The product from the incorporation of absorption is the steady state concentration profile of the absorbed gas species in the bulk liquid phase. The second phase of the model incorporates a simplified macrokinetic model to the mass balance equation in the CMFD code. Initially, the model assumes that the catalyst particles are sufficiently small such that external and internal mass and heat transfer are not rate limiting. The model is developed utilizing the macrokinetic rate expression developed by Yates and Satterfield (1991). Initially, the model assumes that the only species formed other than water in the FT reaction is C27H56. Change in moles of the reacting species and the resulting temperature of the catalyst and fluid phases is solved simultaneously. The macrokinetic model is solved in conjunction with the species transport equations in a separate module which is incorporated into the CMFD code.

  7. 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.

  8. 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.

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

    E-Print Network [OSTI]

    Zhang, Liqing

    2011-07-01T23:59:59.000Z

    is the policy where several small loads will be dispatched as a single, combined load. From an inventory-modeling perspec- tive, the integrated inventory-transportation problems add dispatch quantities as decision variables to the stochastic dynamic inventory...): The vendor makes the inventory replen- ishment decisions on how much to order from the outside supplier. 2. Pure Outbound Transportation Models (PO): The collection depot makes the delivery schedules of order dispatches to the buyer(s). 3. Integrated...

  10. Modeling reaction quench times in the waste heat boiler of a Claus plant

    SciTech Connect (OSTI)

    Nasato, L.V.; Karan, K.; Mehrotra, A.K.; Behie, L.A. (Univ. of Calgary, Alberta (Canada). Dept. of Chemical and Petroleum Engineering)

    1994-01-01T23:59:59.000Z

    At the high temperatures found in the modified Claus reaction furnace, the thermal decomposition and oxidation of H[sub 2]S yields large quantities of desirable products, gaseous hydrogen (H[sub 2]) and sulfur (S[sub 2]). However, as the temperature of the gas stream is lowered in the waste heat boiler (WHB) located downstream of the furnace, the reverse reaction occurs leading to reassociation of H[sub 2] and S[sub 2] molecules. To examine the reaction quenching capabilities of the WHB, a rigorous computer model was developed incorporating recently published intrinsic kinetic data. A sensitivity study performed with the model demonstrated that WHBs have a wide range of operation with gas mass flux in the tubes from 4 to 24 kg/(m[sup 2] [center dot] s). Most important, the model showed that is was possible to operate WHBs such that quench times could be decreased to 40 ms, which is a reduction by 60% compared to a base case scenario. Furthermore, hydrogen production could be increased by over 20% simply by reconfiguring the WHB tubes.

  11. Coal thermolysis modeling: The effects of restricted diffusion on thermal reaction pathways

    SciTech Connect (OSTI)

    Buchanan, A.C. III; Britt, P.F.; Biggs, C.A.

    1989-01-01T23:59:59.000Z

    The technique of model compound immobilization by covalent surface attachment is being employed to investigate the potential impact of restricted diffusional mobility on the thermal reactivity of coal. This restricted mobility may be imposed in coal as a consequence of its cross-linked, macromolecular structure. A detailed study of the thermolysis of surface-immobilized bibenzyl showed that the rate of unimolecular C-C homolysis is similar to that in fluid phases. Recent studies have foucused on the thermally induced, free radical chain decomposition reactions for surface-immobilized 1,3-diphenylpropane and 1,4-diphenylbutane. For 1,4-diphenylbutane both the reaction rate and product composition are strongly dependent on surface coverage and, hence, the proximity of 1.4-diphenylbutane molecules and hydrogen abstracting radicals on the surface. The rates and selectivities of these key bimolecular reaction steps on the surface might also be affected by the structure of neighboring molecules. In the current study, we are beginning to probe this feature by examining the influence of the structure of co-attached aromatic molecules such as biphenyl and diphenylmethane on the reaction rate and regioselectivity in the thermolysis of 1,4-diphenylbutane. 7 refs. , 1 fig., 2 tabs.

  12. 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

  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. 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

  15. A Model of Gas-Phase Transport During the Initial Stages of Sintering of Silicon Carbide

    E-Print Network [OSTI]

    Matthewson, M. John

    A Model of Gas-Phase Transport During the Initial Stages of Sintering of Silicon Carbide Anil Kaza investigate this process using a computational model based on codiffusion of multiple gas species, which This paper describes a computational model that tracks diffu- sion of multiple gas species and so predicts

  16. Nucleus-nucleus cold fusion reactions analyzed with the l-dependent 'fusion by diffusion' model

    SciTech Connect (OSTI)

    Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J. [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Hoza 69, PL-00-681 Warsaw (Poland); Andrzej Soltan Institute for Nuclear Studies, PL-05-400 Otwock-Swierk (Poland)

    2011-05-15T23:59:59.000Z

    We present a modified version of the Fusion by Diffusion (FBD) model aimed at describing the synthesis of superheavy nuclei in cold fusion reactions, in which a low excited compound nucleus emits only one neutron. The modified FBD model accounts for the angular momentum dependence of three basic factors determining the evaporation residue cross section: the capture cross section {sigma}{sub cap}(l), the fusion probability P{sub fus}(l), and the survival probability P{sub surv}(l). The fusion hindrance factor, the inverse of P{sub fus}(l), is treated in terms of thermal fluctuations in the shape degrees of freedom and is expressed as a solution of the Smoluchowski diffusion equation. The l dependence of P{sub fus}(l) results from the l-dependent potential energy surface of the colliding system. A new parametrization of the distance of starting point of the diffusion process is introduced. An analysis of a complete set of 27 excitation functions for production of superheavy nuclei in cold fusion reactions, studied in experiments at GSI Darmstadt, RIKEN Tokyo, and LBNL Berkeley, is presented. The FBD model satisfactorily reproduces shapes and absolute cross sections of all the cold fusion excitation functions. It is shown that the peak position of the excitation function for a given 1n reaction is determined by the Q value of the reaction and the height of the fission barrier of the final nucleus. This fact could possibly be used in future experiments (with well-defined beam energy) for experimental determination of the fission barrier heights.

  17. Oxygen Transport Ceramic Membranes Quarterly Report

    E-Print Network [OSTI]

    Eagar, Thomas W.

    /Reaction rates in Ion 21 Transport Membranes using Isotope Tracer and Transient Kinetic Techniques CONCLUSIONS 30Oxygen Transport Ceramic Membranes Quarterly Report January 2003 ­ March 2003 Principal Authors on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane

  18. 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.

  19. A fully resolved active musculo-mechanical model for esophageal transport

    E-Print Network [OSTI]

    Kou, Wenjun; Griffith, Boyce E; Pandolfino, John E; Kahrilas, Peter J; Patankar, Neelesh A

    2015-01-01T23:59:59.000Z

    Esophageal transport is a physiological process that mechanically transports an ingested food bolus from the pharynx to the stomach via the esophagus, a multi-layered muscular tube. This process involves interactions between the bolus, the esophagus, and the neurally coordinated activation of the esophageal muscles. In this work, we use an immersed boundary (IB) approach to simulate peristaltic transport in the esophagus. The bolus is treated as a viscous fluid that is actively transported by the muscular esophagus, which is modeled as an actively contracting, fiber-reinforced tube. A simplified version of our model is verified by comparison to an analytic solution to the tube dilation problem. Three different complex models of the multi-layered esophagus, which differ in their activation patterns and the layouts of the mucosal layers, are then extensively tested. To our knowledge, these simulations are the first of their kind to incorporate the bolus, the multi-layered esophagus tube, and muscle activation i...

  20. 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).

  1. Complex particle and light fragment emission in the cascade-excitation model of nuclear reactions

    SciTech Connect (OSTI)

    Mashnik, S. G. (Stepan G.); Sierk, A. J. (Arnold J.); Gudima, K. K. (Konstantin K.)

    2002-01-01T23:59:59.000Z

    A brief description of our improvements and refinements that led from the CEM95 version of the Cascade-Exciton Model (CEM) code to CEM97 and to CEM2k is given. The increased accuracy and predictive power of the code CEM2k are shown by several examples. To describe fission and light-fragment (heavier than {sup 4}He) production, the CEM2k code has been merged with the GEM2 code of Furihata. We present some results on proton-induced fragmentation and fission reactios predicted by this extended version of CEM2k. We show that merging CEM2k with GEM2 allows us to describe many fission and fragmentation reactions in addition to the spallation reactions which are already relatively well described.

  2. Including radiative heat transfer and reaction quenching in modeling a Claus plant waste heat boiler

    SciTech Connect (OSTI)

    Karan, K.; Mehrotra, A.K.; Behie, L.A. (Univ. of Calgary, Alberta (Canada). Dept. of Chemical and Petroleum Engineering)

    1994-11-01T23:59:59.000Z

    Due to increasingly stringent sulfur emission regulations, improvements are necessary in the modified Claus process. A recently proposed model by Nasato et al. for the Claus plant waste heat boiler (WHB) is improved by including radiative heat transfer, which yields significant changes in the predicted heat flux and the temperature profile along the WHB tube, leading to a faster quenching of chemical reactions. For the WHB considered, radiation accounts for approximately 20% of the heat transferred by convection alone. More importantly, operating the WHB at a higher gas mass flux is shown to enhance reaction quenching, resulting in a doubling of the predicted hydrogen flow rate. This increase in hydrogen flow rate is sufficient to completely meet the hydrogen requirement of the H[sub 2]S recovery process considered, which would eliminate the need for a hydrogen plant.

  3. Model simulation and experiments of flow and mass transport through a nano-material gas filter

    SciTech Connect (OSTI)

    Yang, Xiaofan; Zheng, Zhongquan C.; Winecki, Slawomir; Eckels, Steve

    2013-11-01T23:59:59.000Z

    A computational model for evaluating the performance of nano-material packed-bed filters was developed. The porous effects of the momentum and mass transport within the filter bed were simulated. For the momentum transport, an extended Ergun-type model was employed and the energy loss (pressure drop) along the packed-bed was simulated and compared with measurement. For the mass transport, a bulk dsorption model was developed to study the adsorption process (breakthrough behavior). Various types of porous materials and gas flows were tested in the filter system where the mathematical models used in the porous substrate were implemented and validated by comparing with experimental data and analytical solutions under similar conditions. Good agreements were obtained between experiments and model predictions.

  4. 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.

  5. 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

  6. 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 ...

  7. 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

  8. 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.

  9. Multiphase transport model for relativistic heavy ion collisions

    E-Print Network [OSTI]

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

    2005-01-01T23:59:59.000Z

    . The full source code of the AMPT model in the FORTRAN 77 language and instructions for users are available online at the OSCAR [60] and EPAPS [61] websites. The default AMPT model is named version 1.x, and the AMPT model with string melting is named...

  10. 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.

  11. Mechanistic studies of photo-induced proton-coupled electron transfer and oxygen atom transfer reactions in model systems

    E-Print Network [OSTI]

    Hodgkiss, Justin M. (Justin Mark), 1978-

    2007-01-01T23:59:59.000Z

    Time-resolved optical spectroscopy has been employed for mechanistic studies in model systems designed to undergo photo-induced proton-coupled electron transfer (PCET) and oxygen atom transfer (OAT) reactions, both of which ...

  12. Phase II Contaminant Transport Parameters for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Nye County, Nevada, Rev. No.: 0

    SciTech Connect (OSTI)

    DeNovio, Nicole M.; Bryant, Nathan; King, Chrissi B.; Bhark, Eric; Drellack, Sigmund L.; Pickens, John F.; Farnham, Irene; Brooks, Keely M.; Reimus, Paul; Aly, Alaa

    2005-04-01T23:59:59.000Z

    This report documents pertinent transport data and data analyses as part of the Phase II Corrective Action Investigation (CAI) for Frenchman Flat (FF) Corrective Action Unit (CAU) 98. The purpose of this data compilation and related analyses is to provide the primary reference to support parameterization of the Phase II FF CAU transport model.

  13. Constructing a Model Transport Equation for a Massless Bose Gas and its Analytic Solution

    E-Print Network [OSTI]

    A. V. Latyshev; A. A. Yushkanov

    2010-12-14T23:59:59.000Z

    A model kinetic equation is constructed for the transport of a massless Bose gas. This equation is applied to solution of the boundary value problem for the transport of radiation in the half-space occupied by a dispersive medium that is in local thermal equilibrium with the radiation. It is shown that the difference in temperature between the dispersive medium and the incident radiation depends substantially on the character of the scattering properties of the particles of the medium.

  14. 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

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

    E-Print Network [OSTI]

    Stroud, Jonathan

    by combining the satellite data with the numerical model. In our application, we find that data assimilationAssimilation of satellite images into a sediment transport model of Lake Michigan Jonathan R consider two data assimilation methods, direct insertion and a kriging-based approach, and perform

  16. ABSORPTION-DELAY MODELS OF HEAT TRANSPORT R.E. SHOWALTER AND D.B. VISARRAGA

    E-Print Network [OSTI]

    ABSORPTION-DELAY MODELS OF HEAT TRANSPORT R.E. SHOWALTER AND D.B. VISARRAGA Abstract. A temperature jump in the water traveling through a pipe is delayed by the absorption of heat into the pipe wall transfer, absorption, memory, kinetic models, approximation. 1 #12;2 R.E. SHOWALTER AND D.B. VISARRAGA 1

  17. Identification of Segments of French Urban Public Transport with a Latent Class Frontier Model

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Identification of Segments of French Urban Public Transport with a Latent Class Frontier Model from 1995 to 2002 with unbalanced panel data. The latent class frontier model is used allowing the identification of different segments in the production frontier. We find that there are three statistically

  18. Proton-hydrogen reaction in an effectively two-body model

    SciTech Connect (OSTI)

    Pupyshev, V. V., E-mail: pupyshev@theor.jinr.ru [Joint Institute for Nuclear Research (Russian Federation)

    2013-02-15T23:59:59.000Z

    A model of total interaction between a proton incident to a hydrogen atom and the proton that is the nucleus of this atom is proposed. This interaction is assumed to be the sum of the short-range nuclear Reid potential and the long-range Thomas-Fermi potential induced by the Coulomb interaction of the electron with the nucleus of the hydrogen atom. The explicit low-energy asymptotic behavior of the cross section for the proton-hydrogen reaction leading to deuteron production is found. It is shown that this cross section increases in inverse proportion to the collision energy for the proton and hydrogen atom in its zero limit.

  19. A comparative study of reaction rate, species, and vibration-dissociation coupling models for an AOTV flowfield

    E-Print Network [OSTI]

    Bobskill, Glenn James

    1988-01-01T23:59:59.000Z

    A COMPARATIVE STUDY OF REACTION RATE, SPECIES, AND VIBRATION DISSOCIATION COUPLING MODELS FOR AN AOTV FLOWFIELD A Thesis by GLENN JAMES BOBSKILL Submitted to the Graduate College of Texas A&M UniversitY in partial fulfillment... of the requirements for the degree of MASTER GF SC. BNCH August 1938 Major Subject: Aerospace Engineering A COMPARATIVE STUDY OF REACTION RATE, SPECIES, AND VIBRATION -DISSOCIATION COUPLING MODELS FOR AN AOTV FLOWFIELD A Thesis by GLENN JAMES BOBSKILL...

  20. 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.

  1. 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...

  2. Lattice gas automata for flow and transport in geochemical systems

    SciTech Connect (OSTI)

    Janecky, D.R.; Chen, S.; Dawson, S.; Eggert, K.C.; Travis, B.J.

    1992-05-01T23:59:59.000Z

    Lattice gas automata models are described, which couple solute transport with chemical reactions at mineral surfaces within pore networks. Diffusion in a box calculations are illustrated, which compare directly with Fickian diffusion. Chemical reactions at solid surfaces, including precipitation/dissolution, sorption, and catalytic reaction, can be examined with the model because hydrodynamic transport, solute diffusion and mineral surface processes are all treated explicitly. The simplicity and flexibility of the approach provides the ability to study the interrelationship between fluid flow and chemical reactions in porous materials, at a level of complexity that has not previously been computationally possible.

  3. Lattice gas automata for flow and transport in geochemical systems

    SciTech Connect (OSTI)

    Janecky, D.R.; Chen, S.; Dawson, S.; Eggert, K.C.; Travis, B.J.

    1992-01-01T23:59:59.000Z

    Lattice gas automata models are described, which couple solute transport with chemical reactions at mineral surfaces within pore networks. Diffusion in a box calculations are illustrated, which compare directly with Fickian diffusion. Chemical reactions at solid surfaces, including precipitation/dissolution, sorption, and catalytic reaction, can be examined with the model because hydrodynamic transport, solute diffusion and mineral surface processes are all treated explicitly. The simplicity and flexibility of the approach provides the ability to study the interrelationship between fluid flow and chemical reactions in porous materials, at a level of complexity that has not previously been computationally possible.

  4. Dynamical coupled-channels model of $K^- p$ reactions (I): Determination of partial-wave amplitudes

    E-Print Network [OSTI]

    H. Kamano; S. X. Nakamura; T. -S. H. Lee; T. Sato

    2014-12-12T23:59:59.000Z

    We develop a dynamical coupled-channels model of K^- p reactions, aiming at extracting the parameters associated with hyperon resonances and providing the elementary antikaon-nucleon scattering amplitudes that can be used for investigating various phenomena in the strangeness sector such as the production of hypernuclei from kaon-nucleus reactions. The model consists of (a) meson-baryon (MB) potentials v_{M'B',MB} derived from the phenomenological SU(3) Lagrangian, and (b) vertex interactions Gamma_{MB,Y*} for describing the decays of the bare excited hyperon states (Y*) into MB states. The model is defined in a channel space spanned by the two-body barK N, pi Sigma, pi Lambda, eta Lambda, and K Xi states and also the three-body pi pi Lambda and pi barK N states that have the resonant pi Sigma* and barK* N components, respectively. The resulting coupled-channels scattering equations satisfy the multichannel unitarity conditions and account for the dynamical effects arising from the off-shell rescattering processes. The model parameters are determined by fitting the available data of the unpolarized and polarized observables of the K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi reactions in the energy region from the threshold to invariant mass W=2.1 GeV. Two models with equally good chi^2 fits to the data have been constructed. The partial-wave amplitudes obtained from the constructed models are compared with the results from a recent partial-wave analysis by the Kent State University group. We discuss the differences between these three analysis results. Our results at energies near the threshold suggest that the higher partial waves should be treated on the same footing as the S wave if one wants to understand the nature of Lambda(1405)1/2^- using the data below the barK N threshold, as will be provided by the J-PARC E31 experiment.

  5. 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)

  6. 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.

  7. Modeling the coupled mechanics, transport, and growth processes in collagen tissues.

    SciTech Connect (OSTI)

    Holdych, David J.; Nguyen, Thao D.; Klein, Patrick A.; in't Veld, Pieter J.; Stevens, Mark Jackson

    2006-11-01T23:59:59.000Z

    The purpose of this project is to develop tools to model and simulate the processes of self-assembly and growth in biological systems from the molecular to the continuum length scales. The model biological system chosen for the study is the tendon fiber which is composed mainly of Type I collagen fibrils. The macroscopic processes of self-assembly and growth at the fiber scale arise from microscopic processes at the fibrillar and molecular length scales. At these nano-scopic length scales, we employed molecular modeling and simulation method to characterize the mechanical behavior and stability of the collagen triple helix and the collagen fibril. To obtain the physical parameters governing mass transport in the tendon fiber we performed direct numerical simulations of fluid flow and solute transport through an idealized fibrillar microstructure. At the continuum scale, we developed a mixture theory approach for modeling the coupled processes of mechanical deformation, transport, and species inter-conversion involved in growth. In the mixture theory approach, the microstructure of the tissue is represented by the species concentration and transport and material parameters, obtained from fibril and molecular scale calculations, while the mechanical deformation, transport, and growth processes are governed by balance laws and constitutive relations developed within a thermodynamically consistent framework.

  8. 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.

  9. 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.

  10. PATHWAY: a simulation model of radionuclide-transport through agricultural food chains

    SciTech Connect (OSTI)

    Kirchner, T.B.; Whicker, F.W.; Otis, M.D.

    1982-01-01T23:59:59.000Z

    PATHWAY simulates the transport of radionuclides from fallout through an agricultural ecosystem. The agro-ecosystem is subdivided into several land management units, each of which is used either for grazing animals, for growing hay, or for growing food crops. The model simulates the transport of radionuclides by both discrete events and continuous, time-dependent processes. The discrete events include tillage of soil, harvest and storage of crops,and deposition of fallout. The continuous processes include the transport of radionuclides due to resuspension, weathering, rain splash, percolation, leaching, adsorption and desorption of radionuclides in the soil, root uptake, foliar absorption, growth and senescence of vegetation, and the ingestion assimilation, and excretion of radionuclides by animals. Preliminary validation studies indicate that the model dynamics and simulated values of radionuclide concentrations in several agricultural products agree well with measured values when the model is driven with site specific data on deposition from world-wide fallout.

  11. Application of computer modeling techniques to the kinetics of the reaction of carbon with oxygen

    SciTech Connect (OSTI)

    Ahmed, S.; Back, M.H.; Roscoe, J.M.

    1989-01-01T23:59:59.000Z

    Computer modeling techniques are applied to the kinetics of the reaction of carbon with oxygen. The rates of disappearance of oxygen, of formation of CO, CO/sub 2/ and the surface complex, measured over the temperature range 748-1173 K and the pressure range 0.5-400 Pa may be described by a mechanism involving adsorption of oxygen, formation of the strongly-bound complex, desorption of the complex and reaction of the complex with a gas-phase molecule of oxygen. The latter is shown to be an important source of CO/sub 2/ at low temperatures and higher pressures of oxygen. An important feature of the mechanism is the existence of at least two distinct types of active sites for the binding of the complex on the carbon surface, each with a characteristic reactivity. Most of the results on which the model is based were obtained using thin films of pyrolytic carbon, but some results from the oxidation of graphon are also consistent with the mechanism.

  12. Modeling precursor diffusion and reaction of atomic layer deposition in porous structures

    SciTech Connect (OSTI)

    Keuter, Thomas, E-mail: t.keuter@fz-juelich.de; Menzler, Norbert Heribert; Mauer, Georg; Vondahlen, Frank; Vaen, Robert; Buchkremer, Hans Peter [Forschungszentrum Jlich, Institute of Energy and Climate Research (IEK-1), 52425 Jlich (Germany)

    2015-01-01T23:59:59.000Z

    Atomic layer deposition (ALD) is a technique for depositing thin films of materials with a precise thickness control and uniformity using the self-limitation of the underlying reactions. Usually, it is difficult to predict the result of the ALD process for given external parameters, e.g., the precursor exposure time or the size of the precursor molecules. Therefore, a deeper insight into ALD by modeling the process is needed to improve process control and to achieve more economical coatings. In this paper, a detailed, microscopic approach based on the model developed by Yanguas-Gil and Elam is presented and additionally compared with the experiment. Precursor diffusion and second-order reaction kinetics are combined to identify the influence of the porous substrate's microstructural parameters and the influence of precursor properties on the coating. The thickness of the deposited film is calculated for different depths inside the porous structure in relation to the precursor exposure time, the precursor vapor pressure, and other parameters. Good agreement with experimental results was obtained for ALD zirconiumdioxide (ZrO{sub 2}) films using the precursors tetrakis(ethylmethylamido)zirconium and O{sub 2}. The derivation can be adjusted to describe other features of ALD processes, e.g., precursor and reactive site losses, different growth modes, pore size reduction, and surface diffusion.

  13. 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...

  14. On EOQ Cost Models with Arbitrary Purchase and Transportation ...

    E-Print Network [OSTI]

    Birbil

    2014-03-02T23:59:59.000Z

    In inventory control, the economic order quantity cost model (EOQ) is the most fundamental ... it is possible to evaluate this upper bound by means of an algorithm. .... Noting that the convexity structure does not change within each interval, Lee...

  15. 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...

  16. 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.

  17. Lattice-gas model for active vesicle transport by molecular motors with opposite polarities

    E-Print Network [OSTI]

    Sudipto Muhuri; Ignacio Pagonabarraga

    2010-09-09T23:59:59.000Z

    We introduce a multi-species lattice gas model for motor protein driven collective cargo transport on cellular filaments. We use this model to describe and analyze the collective motion of interacting vesicle cargoes being carried by oppositely directed molecular motors, moving on a single biofilament. Building on a totally asymmetric exclusion process (TASEP) to characterize the motion of the interacting cargoes, we allow for mass exchange with the environment, input and output at filament boundaries and focus on the role of interconversion rates and how they affect the directionality of the net cargo transport. We quantify the effect of the various different competing processes in terms of non-equilibrium phase diagrams. The interplay of interconversion rates, which allow for flux reversal and evaporation/deposition processes introduce qualitatively new features in the phase diagrams. We observe regimes of three-phase coexistence, the possibility of phase re-entrance and a significant flexibility in how the different phase boundaries shift in response to changes in control parameters. The moving steady state solutions of this model allows for different possibilities for the spatial distribution of cargo vesicles, ranging from homogeneous distribution of vesicles to polarized distributions, characterized by inhomogeneities or {\\it shocks}. Current reversals due to internal regulation emerge naturally within the framework of this model. We believe this minimal model will clarify the understanding of many features of collective vesicle transport, apart from serving as the basis for building more exact quantitative models for vesicle transport relevant to various {\\it in-vivo} situations.

  18. A Practical Model for Subsurface Light Transport Henrik Wann Jensen Stephen R. Marschner Marc Levoy Pat Hanrahan

    E-Print Network [OSTI]

    O'Brien, James F.

    by solving the full radiative transfer equation [1]. Only a few papers in graphics have taken this approachA Practical Model for Subsurface Light Transport Henrik Wann Jensen Stephen R. Marschner Marc Levoy transport in translucent materials. The model enables efficient simulation of effects that BRDF models

  19. 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.

  20. 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.

  1. 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 realizabilitythat 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.

  2. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    SciTech Connect (OSTI)

    P. Tucci

    2001-12-20T23:59:59.000Z

    This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M&O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment.

  3. 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 turbulencechemistry interactions, although the details of the mixing model do not make a large difference in the results, within reasonable limits.

  4. Simplified 1-D Hydrodynamic and Salinity Transport Modeling of the SacramentoSan 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 SacramentoSan Joaquinhydrodynamic and salinity transport mod- eling of the SacramentoSan Joaquin

  5. 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)

  6. 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 variables Stephan Gadau, Ansgar J¨ungel, and Paola Pietra Abstract. One-dimensional stationary energy employing a mixed-hybrid finite- element method which has the advantage to fulfill current conser- vation

  7. 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.

  8. Equidimensional modelling of ow and transport processes in fractured porous systems I

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    decomposition into a fracture problem and a matrix problem. This decoupled treatment of fracture and matrix;erent hydraulic properties of fractures and the porous matrix lead to very heterogeneous ow and trans1 Equidimensional modelling of ow and transport processes in fractured porous systems I Susanna

  9. 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

  10. 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

  11. 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, through open­loop optimization [6, 21, 34]. However, because of process variability and the in­ creasing

  12. MANHAZ position paper on: Modelling of Pollutant Transport in the Atmosphere

    E-Print Network [OSTI]

    MANHAZ position paper on: Modelling of Pollutant Transport in the Atmosphere Torben Mikkelsen July, Denmark I Atmospheric dispersion: Basic The dispersion of pollutants is intimately related to the state 2003 Atmospheric Physics Division Wind Energy Department Risø National Laboratory Dk-4000 Roskilde

  13. 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

  14. Fluctuations in a kinetic transport model for quantum friction

    E-Print Network [OSTI]

    Roland Bauerschmidt; Wojciech de Roeck; Jrg Frhlich

    2014-03-23T23:59:59.000Z

    We consider a linear Boltzmann equation that arises in a model for quantum friction. It describes a particle that is slowed down by the emission of bosons. We study the stochastic process generated by this Boltzmann equation and we show convergence of its spatial trajectory to a multiple of Brownian motion with exponential scaling. The asymptotic position of the particle is finite in mean, even though its absolute value is typically infinite. This is contrasted to an approximation that neglects the influence of fluctuations, where the mean asymptotic position is infinite.

  15. Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

    E-Print Network [OSTI]

    J. C. Misra; S. Maiti

    2011-12-28T23:59:59.000Z

    Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis has been carried out by using lubrication theory. The study is particularly suitable for cases where the Reynolds number is small. The esophagus is treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux are investigated for a single wave as well as for a train of periodic peristaltic waves. Locally variable pressure is seen to be highly sensitive to the flow index `n'. The study clearly shows that continuous fluid transport for Newtonian/rheological fluids by wave train propagation is much more effective than widely spaced single wave propagation in the case of peristaltic movement of food bolus in the esophagus.

  16. Electron spin and the origin of Bio-homochirality II. Prebiotic inorganic-organic reaction model

    E-Print Network [OSTI]

    Wang, Wei

    2014-01-01T23:59:59.000Z

    The emergence of biomolecular homochirality is a critically important question about life phenomenon and the origins of life. In a previous paper (arXiv:1309.1229), I tentatively put forward a new hypothesis that the emergence of a single chiral form of biomolecules in living organisms is specifically determined by the electron spin state during their enzyme-catalyzed synthesis processes. However, how a homochirality world of biomolecules could have formed in the absence of enzymatic networks before the origins of life remains unanswered. Here I discussed the electron spin properties in Fe3S4, ZnS, and transition metal doped dilute magnetic ZnS, and their possible roles in the prebiotic synthesis of chiral molecules. Since the existence of these minerals in hydrothermal vent systems is matter of fact, the suggested prebiotic inorganic-organic reaction model, if can be experimentally demonstrated, may help explain where and how life originated on early Earth.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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 2006; published 17 February 2007. [1] A two-dimensional sediment transport model capable of simulating sediment resuspension of mixed (cohesive plus noncohesive) sediment is developed and applied

  3. 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.

  4. 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.

  5. Transport Modeling of Membrane Extraction of Chlorinated Hydrocarbon from Water for Ion Mobility Spectrometry

    SciTech Connect (OSTI)

    Zhang, Wei [ORNL; Du, Yongzhai [ORNL; Feng, Zhili [ORNL; Xu, Jun [ORNL

    2010-01-01T23:59:59.000Z

    Membrane-extraction Ion Mobility Spectrometry (ME-IMS) is a feasible technique for the continuous monitoring of chlorinated hydrocarbons in water. This work studies theoretically the time-dependent characteristics of sampling and detection of trichloroethylene (TCE). The sampling is configured so that aqueous contaminants permeate through a hollow polydimethylsiloxane (PDMS) membrane and are carried away by a transport gas flowing through the membrane tube into IMS analyzer. The theoretical study is based on a two-dimensional transient fluid flow and mass transport model. The model describes the TCE mixing in the water, permeation through the membrane layer, and convective diffusion in the air flow inside membrane tube. The effect of various transport gas flow rates on temporal profiles of IMS signal intensity is investigated. The results show that fast time response and high transport yield can be achieved for ME-IMS by controlling the flow rate in the extraction membrane tube. These modeled time-response profiles are important for determining duty cycles of field-deployable sensors for monitoring chlorinated hydrocarbons in water.

  6. 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 ...

  7. 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.

  8. 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.

  9. Mathematical Modeling of Transport and Degradation of Feedstuffs in the Small Intestine

    E-Print Network [OSTI]

    Taghipoor, Masoomeh; Georgelin, Christine; Licois, Jean-Ren; Barles, Guy

    2011-01-01T23:59:59.000Z

    We describe a mathematical modeling of the digestion in the small intestine. The main interest of our work is to consider, at the same time, different aspects of the digestion i.e. the transport of the bolus all along the intestine, feedstuffs degradation according to the enzymes and local physical conditions, and nutrients absorption. A system of coupled ordinary differential equations is used to model these phenomena. The major unknowns of this system are the position of the bolus and its composition. This system of equations is solved numerically. We present different numerical computations for the degradation, absorption and transport of the bolus with acceptable accuracy with experimental data. The main feature and interest of this model are its generality. Even if we are at an early stage of development, our approach can be adapted to treat any kind of feedstuffs in any non-ruminant animal to predict the composition and velocity of bolus in the small intestine.

  10. MONTE CARLO SIMULATION MODEL OF ENERGETIC PROTON TRANSPORT THROUGH SELF-GENERATED ALFVEN WAVES

    SciTech Connect (OSTI)

    Afanasiev, A.; Vainio, R., E-mail: alexandr.afanasiev@helsinki.fi [Department of Physics, University of Helsinki (Finland)

    2013-08-15T23:59:59.000Z

    A new Monte Carlo simulation model for the transport of energetic protons through self-generated Alfven waves is presented. The key point of the model is that, unlike the previous ones, it employs the full form (i.e., includes the dependence on the pitch-angle cosine) of the resonance condition governing the scattering of particles off Alfven waves-the process that approximates the wave-particle interactions in the framework of quasilinear theory. This allows us to model the wave-particle interactions in weak turbulence more adequately, in particular, to implement anisotropic particle scattering instead of isotropic scattering, which the previous Monte Carlo models were based on. The developed model is applied to study the transport of flare-accelerated protons in an open magnetic flux tube. Simulation results for the transport of monoenergetic protons through the spectrum of Alfven waves reveal that the anisotropic scattering leads to spatially more distributed wave growth than isotropic scattering. This result can have important implications for diffusive shock acceleration, e.g., affect the scattering mean free path of the accelerated particles in and the size of the foreshock region.

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

    SciTech Connect (OSTI)

    Bikowski, Andr, E-mail: andre.bikowski@helmholtz-berlin.de; Ellmer, Klaus [Helmholtz-Zentrum Berlin fr 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.

  12. 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

  13. Peristaltic Transport of a Rheological Fluid: Model for Movement of Food Bolus Through Esophagus

    E-Print Network [OSTI]

    Misra, J C

    2011-01-01T23:59:59.000Z

    Fluid mechanical peristaltic transport through esophagus has been of concern in the paper. A mathematical model has been developed with an aim to study the peristaltic transport of a rheological fluid for arbitrary wave shapes and tube lengths. The Ostwald-de Waele power law of viscous fluid is considered here to depict the non-Newtonian behaviour of the fluid. The model is formulated and analyzed with the specific aim of exploring some important information concerning the movement of food bolus through the esophagus. The analysis has been carried out by using lubrication theory. The study is particularly suitable for cases where the Reynolds number is small. The esophagus is treated as a circular tube through which the transport of food bolus takes places by periodic contraction of the esophageal wall. Variation of different variables concerned with the transport phenomena such as pressure, flow velocity, particle trajectory and reflux are investigated for a single wave as well as for a train of periodic per...

  14. The Role of Dispersion in Radionuclide Transport - Data and Modeling Requirements: Revision No. 1

    SciTech Connect (OSTI)

    Stoller-Navarro Joint Venture

    2004-02-01T23:59:59.000Z

    This document is the collaborative effort of the members of an ad hoc subcommittee of the Underground Test Area Project Technical Working Group. This subcommittee was to answer questions and concerns raised by the Nevada Division of Environmental Protection to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, regarding Pahute Mesa Corrective Action Units (CAUs) 101 and 102. The document attempts to synthesize the combined comments made by each member of this subcommittee into insights made in the role of dispersion in radionuclide transport data and modeling. Dispersion is one of many processes that control the concentration of radionuclides in groundwater beneath the Nevada Test Site where CAUs 101 and 102 are located. In order to understand the role of dispersion in radionuclide transport, there is a critical need for CAU- or site-specific data related to transport parameters which is currently lacking, particularly in the case of Western a nd Central Pahute Mesa. The purpose of this technical basis document is to: (1) define dispersion and its role in contaminant transport, (2) present a synopsis of field-scale dispersion measurements, (3) provide a literature review of theories to explain field-scale dispersion, (4) suggest approaches to account for dispersion in CAU-scale radionuclide modeling, and (5) to determine if additional dispersion measurements should be made at this time.

  15. Conceptual model for regional radionuclide transport from a basalt repository site. Final draft, technical memorandum

    SciTech Connect (OSTI)

    Walton, W.C.; Voorhees, M.L.; Prickett, T.A.

    1980-05-23T23:59:59.000Z

    This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.

  16. 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.

  17. 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.

  18. J/psi production in relativistic heavy ion collisions from a multiphase transport model

    E-Print Network [OSTI]

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

    2002-01-01T23:59:59.000Z

    for the present study is a hybrid model based on three Monte Carlo models for the three stages of relativistic heavy ion collisions, i.e., the heavy ion jet interaction generator J?c production in relativistic heavy ion collision Bin Zhang,1 C.M. Ko,2 Bao...V. With this dynamic transport model, we find that the net number of produced J/c from the parton and hadron phases is smaller than that expected from initial nucleon-nucleon collisions, contrary to the J/c en- ?2002 The American Physical Society1 ZHANG, KO, LI...

  19. 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.

  20. Comparison of palladium and platinum Water Gas Shift reaction kinetics using density functional theory models.

    E-Print Network [OSTI]

    Clay, John P.

    2014-01-01T23:59:59.000Z

    ?? The Water Gas Shift (WGS) reaction can be either thermodynamically or kinetically limited, depending on process conditions. Improved catalysts are of particular interest at (more)

  1. Comparative study of micromixing models in transported scalar PDF simulations of turbulent nonpremixed bluff body flames

    SciTech Connect (OSTI)

    Merci, Bart [Department of Flow, Heat and Combustion Mechanics, Ghent University-UGent, Ghent (Belgium); Roekaerts, Dirk [Department of Multi-Scale Physics, Delft University of Technology, Delft (Netherlands); Naud, Bertrand [CIEMAT, Madrid (Spain); Pope, Stephen B. [Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY (United States)

    2006-07-15T23:59:59.000Z

    Numerical simulation results are presented for turbulent jet diffusion flames with various levels of turbulence-chemistry interaction, stabilized behind a bluff body (Sydney Flames HM1-3). Interaction between turbulence and combustion is modeled with the transported joint-scalar PDF approach. The mass density function transport equation is solved in a Lagrangian manner. A second-moment-closure turbulence model is applied to obtain accurate mean flow and turbulent mixing fields. The behavior of two micromixing models is discussed: the Euclidean minimum spanning tree model and the modified Curl coalescence dispersion model. The impact of the micromixing model choice on the results in physical space is small, although some influence becomes visible as the amount of local extinction increases. Scatter plots and profiles of conditional means and variances of thermochemical quantities, conditioned on the mixture fraction, are discussed both within and downstream of the recirculation region. A distinction is made between local extinction and incomplete combustion, based on the CO species mass fraction. The differences in qualitative behavior between the micromixing models are explained and quantitative comparison to experimental data is made. (author)

  2. Uniqueness for an ill-posed reaction-dispersion model. Application to organic pollution in stream-waters

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Uniqueness for an ill-posed reaction-dispersion model. Application to organic pollution in stream-waters waters. The sources we consider are point-wise and simulate stationary or moving pollution sources to measure the pollution extent due to organic agents and then to evaluate the water characteristics. Another

  3. 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 ...

  4. Determining the Effect of Concerted Elimination Reactions in the Pyrolysis of Lignin Using Model Compounds

    SciTech Connect (OSTI)

    Robichaud, D.; Clark, J.; Nimlos, M.

    2012-01-01T23:59:59.000Z

    Lignin pyrolysis is a significant impediment in forming liquid fuel from biomass. Lignin pyrolyzes at a higher temperature than other biomass components (ie cellulose, hemicellulose) and tends to form radicals which lead to cross linking and ultimately char formation. A primary step in advances biomass-to-fuel technology will be to discover mechanisms that can disassemble lignin at lower temperatures and depolymerize lignin into more stable products. We have investigated the thermochemistry of the various inter-linkage units found in lignin ({beta}-O4, {alpha}-O4, {beta}-{beta}, {beta}-O5, etc) using electronic structure calculations at the M06-2x/6-311++G(d,p) on a series of dimer model compounds. In addition to the usually-assumed bond homolysis reactions, we have investigated a variety of concerted elimination pathways that will tend to produce closed-shell stable products. Such a bottom-up approach could aid in the targeted development of catalysts that produce more desirable products under less severe reactor conditions.

  5. Microscopic Description of the Exotic Nuclei Reactions by Using Folding model Potentials

    SciTech Connect (OSTI)

    Ibraheem, Awad A. [Physics Department, Al-Azhar University, Assiut Branch, Assiut 71524 (Egypt); Physics Department, King Khalid University, Abha (Saudi Arabia); Hassanain, M. A. [Physics Department, King Khalid University, Abha (Saudi Arabia); Sciences Department, New-Valley Faculty of Education, Assiut University, El-Kharga, New-Valley (Egypt); Mokhtar, S. R.; El-Azab Farid, M. [Physics Department, Assiut University, Assiut 71516 (Egypt); Zaki, M. A. [Physics Department, South-Valley University, Aswan (Egypt); Mahmoud, Zakaria M. M. [Sciences Department, New-Valley Faculty of Education, Assiut University, El-Kharga, New-Valley (Egypt)

    2011-10-27T23:59:59.000Z

    A microscopic folding approach based upon the effective M3Y nucleon-nucleon interaction and the nuclear matter densities of the interacting nuclei has been carried out to explain recently measured experimental data of the {sup 6}He+{sup 120}Sn elastic scattering reaction at four different laboratory energies near the Coulomb barrier. The corresponding reaction cross sections are also considered.

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

  7. 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.

  8. 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.

  9. Comparison of one-, two-, and three-dimensional models for mass transport of radionuclides

    SciTech Connect (OSTI)

    Prickett, T.A.; Voorhees, M.L.; Herzog, B.L.

    1980-02-01T23:59:59.000Z

    This technical memorandum compares one-, two-, and three-dimensional models for studying regional mass transport of radionuclides in groundwater associated with deep repository disposal of high-level radioactive wastes. In addition, this report outlines the general conditions for which a one- or two-dimensional model could be used as an alternate to a three-dimensional model analysis. The investigation includes a review of analytical and numerical models in addition to consideration of such conditions as rock and fluid heterogeneity, anisotropy, boundary and initial conditions, and various geometric shapes of repository sources and sinks. Based upon current hydrologic practice, each review is taken separately and discussed to the extent that the researcher can match his problem conditions with the minimum number of model dimensions necessary for an accurate solution.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Area-preserving maps models of gyroaveraged EB chaotic transport

    SciTech Connect (OSTI)

    Fonseca, J. D. da, E-mail: jfonseca@if.usp.br; Caldas, I. L., E-mail: ibere@if.usp.br [Institute of Physics, University of So Paulo, So Paulo, SP 5315-970 (Brazil); Castillo-Negrete, D. del, E-mail: delcastillod@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States)

    2014-09-15T23:59:59.000Z

    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 E??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 the counting of recurrences times are used to quantify the dependence on the Larmor radius of the threshold for the destruction of transport barriers.

  15. 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.

  16. 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

  17. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    SciTech Connect (OSTI)

    Hufnagel, Todd C.

    2014-06-09T23:59:59.000Z

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  18. Finite element modelling of transport and drift effects in tokamak divertor and SOL

    SciTech Connect (OSTI)

    Simard, M.; Marchand, R. [INRS-Energie et Materiaux, Varennes, Quebec (Canada); Boucher, C.; Gunn, J.P. [Centre Canadien de Fusion Magnetique, Varennes, Quebec (Canada)] [and others

    1996-12-31T23:59:59.000Z

    A finite element code is used to simulate transport of a single-species plasma in the edge and divertor of a tokamak. The physical model is based on Braginskii`s fluid equations for the conservation of particles, parallel momentum, ion and electron energy. In modelling recycling, transport of neutral density and energy is treated in the diffusion approximation. The electrostatic potential is obtained from the generalized Ohm`s law. It is used to compute the electric field and the associated E x B drift. In a first approximation, transport is assumed to be ambipolar. The system of equations is discretized on an unstructured triangular mesh, thus permitting good spatial resolution near the X-point and an accurate description of divertor plates of arbitrary shape. Special care must be taken to prevent numerical corruption of the highly anisotropic thermal diffusion. Comparisons will be made between simulations and experimental results from TdeV. This will focus, in particular, on density and temperature profiles at the divertor plates, and on the plasma parallel velocity in the SOL. The asymmetry in the power deposited to the inner and outer divertors and the effect of magnetic field reversal will be considered. Comparisons with B2-Eirene simulation results will also be presented.

  19. 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.

  20. Characterization and activity of ferric-sulfide-based catalyst in model reactions of direct coal liquefaction: Effect of preparation conditions

    SciTech Connect (OSTI)

    Chadha, A.; Stinespring, C.D.; Stiller, A.H.; Zondlo, J.W.; Dadyburjor, D.B. [West Virginia Univ., Morgantown, WV (United States). Dept. of Chemical Engineering] [West Virginia Univ., Morgantown, WV (United States). Dept. of Chemical Engineering

    1997-02-01T23:59:59.000Z

    The authors studied the activity of various ferric-sulfide-based catalysts in model hydrogenation and cracking reactions under conditions typical of direct coal liquefaction (DCL). The catalysts used were mixtures of FeS{sub 2} (pyrite, PY) and nonstoichiometric FeS{sub x} (pyrrhotite, PH) obtained by high-temperature disproportionation of ferric sulfide in a nitrogen atmosphere or a hydrogen atmosphere. The structural changes in the catalyst were also examined, both before and after the model reactions. The cracking functionality of the catalysts was studied by using cumene, and the hydrocracking functionality was studied by using diphenylmethane. Phenanthrene was used as a model compound for hydrogenation and hydrogen shuttling. Phenanthrene hydrogenation was studied in the presence of H{sub 2}(g), and hydrogen shuttling was studied when a hydrogen donor (tetralin) was present in the absence of H{sub 2}(g). All the model reactions were performed under conditions typical of DCL: 400 C and 1,000 psig for 30 min. The surface and bulk of the catalysts were characterized by Auger electron spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and atomic absorption spectroscopy. The performance of the catalysts was found to vary with the type of reaction, the initial ratio of FeS{sub x} to FeS{sub 2} (PH/PY) found in the catalyst, and the catalyst age. Catalysts freshly prepared in a nitrogen atmosphere were most active for model hydrogenation and hydrocracking runs. Catalysts freshly prepared in hydrogen were most active in shuttling. A simple model was developed to explain changes in the surface and bulk of the catalysts.

  1. Kinetics of intrachain reactions of supercoiled DNA: Theory and numerical modeling

    E-Print Network [OSTI]

    Langowski, Jörg

    . Klenin and Jo¨rg Langowskia) Division Biophysics of Macromolecules, German Cancer Research Center, Im analytical approach has yet been found. It is clear that the rate of a very slow reaction is deter- mined that the activity

  2. Model microfluidic platform prototyping : design and fabrication of a Polymerase Chain Reaction (PCR) chip

    E-Print Network [OSTI]

    Kumar, Sumeet, Ph. D. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    Polymerase Chain Reaction (PCR) is a molecular biology method for the in vitro amplification of nucleic acid molecules, which has wide applications in the areas of genetics, medicine and biochemistry. MEMS technology offers ...

  3. 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.

  4. Automated reaction mechanism generation : data collaboration, Heteroatom implementation, and model validation

    E-Print Network [OSTI]

    Harper, Michael Richard, Jr

    2011-01-01T23:59:59.000Z

    Nearly two-thirds of the United States' transportation fuels are derived from non-renewable fossil fuels. This demand of fossil fuels requires the United States to import ~ 60% of its total fuel consumption. Relying so ...

  5. A two-phase flow model of sediment transport: transition from bedload to suspended load

    E-Print Network [OSTI]

    Filippo Chiodi; Philippe Claudin; Bruno Andreotti

    2014-09-02T23:59:59.000Z

    The transport of dense particles by a turbulent flow depends on two dimensionless numbers. Depending on the ratio of the shear velocity of the flow to the settling velocity of the particles (or the Rouse number), sediment transport takes place in a thin layer localized at the surface of the sediment bed (bedload) or over the whole water depth (suspended load). Moreover, depending on the sedimentation Reynolds number, the bedload layer is embedded in the viscous sublayer or is larger. We propose here a two-phase flow model able to describe both viscous and turbulent shear flows. Particle migration is described as resulting from normal stresses, but is limited by turbulent mixing and shear-induced diffusion of particles. Using this framework, we theoretically investigate the transition between bedload and suspended load.

  6. 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 ...

  7. 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.

  8. 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.

  9. 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 Days Creek discharge location on the order of 40 years. Travel times from the old process area to Days 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.

  10. 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.

  11. 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.

  12. 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.

  13. Modeling of Gas Phase Transport and Composition Evolution during the Initial Stage Sintering of Boron Carbide with Carbon Additions

    E-Print Network [OSTI]

    Matthewson, M. John

    1 Modeling of Gas Phase Transport and Composition Evolution during the Initial Stage Sintering the pores close. This process is examined using a computational model based on co-diffusion of multiple gas is to model the gas diffusion to determine the needed hold time as a function of key parameters

  14. 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.

  15. 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.

  16. 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.

  17. Application of multidimensional analytical transport models to coal-tar derivatives

    E-Print Network [OSTI]

    Sim, Youn

    1992-01-01T23:59:59.000Z

    by the contaminants (Hult and Schoenberg, 1984) . MINNESOTA 93'30 a-r'r , oar O ba HE N NE PIN v' . Minneapolis South and Hopkins Ouadranplen Lake Minn tonke ST. LOINS St. Paul ANOKA l 93' U i WASHINGTON 1 RAMSEY trl 'Z C 3 CI tn 45' l 10 l... first order kinetic reaction. The essence of the Domenico and Robbins model is apparent in Fig. 3. Because of an assumed one- dimensional velocity, the plume shown in Fig. 3d can be Source Source Co ll k C? II k (a) Source Source II k I 1...

  18. 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

    Groundwater Reactive Transport Models, 2012, 141-159 141 Fan Zhang, Gour-Tsyh (George) Yeh, Jack C: Reactive Flow & Transport Code for Use on Laptops to Leadership-Class Supercomputers G. E. Hammond1 , P. C, a next-generation reactive flow and transport code for modeling subsurface processes, has been designed

  19. 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.

  20. Exotic quantum transport in double-stranded Kronig-Penney model

    E-Print Network [OSTI]

    Taksu Cheon; Sergey S. Poghosyan

    2014-10-31T23:59:59.000Z

    We introduce 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.

  1. 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.

  2. Comparing three vegetation monoterpene emission models to measured gas concentrations with a model of meteorology, air chemistry and chemical transport

    SciTech Connect (OSTI)

    Smolander, S.; He, Q.; Mogensen, Ditte; Zhou, L.; Back, J.; Ruuskanen, T.; Noe, S.; Guenther, Alex B.; Aaltonen, H.; Kulmala, M.; Boy, Michael

    2014-10-07T23:59:59.000Z

    Biogenic volatile organic compounds (BVOCs) are essential in atmospheric chemistry because of their chemical reactions that produce and destroy tropospheric ozone, their effects on aerosol formation and growth, and their potential influence on global warming. As one of the important BVOC groups, monoterpenes have been a focus of scientific attention in atmospheric research. Detailed regional measurements and model estimates are needed to study emission potential and the monoterpene budget on a global scale. Since the use of empirical measurements for upscaling is limited by many physical and biological factors such as genetic variation, temperature and light, water availability, seasonal changes, and environmental stresses, comprehensive inventories over larger areas are difficult to obtain.

  3. Characterization and Reaction Studies of Silica Supported Platinum and Rhodium Model Catalysts

    E-Print Network [OSTI]

    Lundwall, Matthew James

    2012-02-14T23:59:59.000Z

    at which a chemical reaction approaches equilibrium and does not itself undergo a net chemical change.1 When a catalyst is in a different phase (e.g. solid) than a reactant mixture it is defined as a heterogeneous catalyst. Two types of heterogeneous... concerning the active-nature of the surface. For what reasons, on an atomic level, are surfaces capable of sustaining a reaction and others deactivate? What effect does particle size/structure have on activity and selectivity? Is this an electronic...

  4. 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 Laboratorys 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.

  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. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    SciTech Connect (OSTI)

    K. Rehfeldt

    2004-10-08T23:59:59.000Z

    This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In addition to being utilized by the SZ site-scale flow model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for groundwater management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model and provides information useful to estimation of the magnitude and direction of lateral groundwater flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment (TSPA).

  7. 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.

  8. 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.

  9. AURORA: A FORTRAN program for modeling well stirred plasma and thermal reactors with gas and surface reactions

    SciTech Connect (OSTI)

    Meeks, E.; Grcar, J.F.; Kee, R.J. [Sandia National Labs., Livermore, CA (United States). Thermal and Plasma Processes Dept.] [Sandia National Labs., Livermore, CA (United States). Thermal and Plasma Processes Dept.; Moffat, H.K. [Sandia National Labs., Albuquerque, NM (United States). Surface Processing Sciences Dept.] [Sandia National Labs., Albuquerque, NM (United States). Surface Processing Sciences Dept.

    1996-02-01T23:59:59.000Z

    The AURORA Software is a FORTRAN computer program that predicts the steady-state or time-averaged properties of a well mixed or perfectly stirred reactor for plasma or thermal chemistry systems. The software was based on the previously released software, SURFACE PSR which was written for application to thermal CVD reactor systems. AURORA allows modeling of non-thermal, plasma reactors with the determination of ion and electron concentrations and the electron temperature, in addition to the neutral radical species concentrations. Well stirred reactors are characterized by a reactor volume, residence time or mass flow rate, heat loss or gas temperature, surface area, surface temperature, the incoming temperature and mixture composition, as well as the power deposited into the plasma for non-thermal systems. The model described here accounts for finite-rate elementary chemical reactions both in the gas phase and on the surface. The governing equations are a system of nonlinear algebraic relations. The program solves these equations using a hybrid Newton/time-integration method embodied by the software package TWOPNT. The program runs in conjunction with the new CHEMKIN-III and SURFACE CHEMKIN-III packages, which handle the chemical reaction mechanisms for thermal and non-thermal systems. CHEMKIN-III allows for specification of electron-impact reactions, excitation losses, and elastic-collision losses for electrons.

  10. The K{sup }N?K? reaction in coupled channel chiral models up to next-to-leading order

    SciTech Connect (OSTI)

    Magas, V. K.; Ramos, A. [Dept. d'Estructura i Constituents de la Matria, Universitat de Barcelona, Mart Franqus 1, E08028 Barcelona, Spain and Institut de Cincies del Cosmos, Universitat de Barcelona, Mart Franqus 1, E08028 Bar (Spain); Feijoo, A. [Dept. d'Estructura i Constituents de la Matria, Universitat de Barcelona, Mart Franqus 1, E08028 Barcelona (Spain)

    2014-07-23T23:59:59.000Z

    We study the meson-baryon interaction in S-wave in the strangeness S=?1 sector using a chiral unitary approach based on a next-to-leading order chiral SU(3) Lagrangian. We fit our model to the large set of experimental data in different two-body channels. We pay particular attention to the K{sup }N?K? reaction, where the effect of the next-to-leading order terms in the Lagrangian are sufficiently large to be observed, since at tree level the cross section of this reaction is zero. For these channels we improve our approach by phenomenologically taking into account effects of the high spin hyperonic resonances.

  11. 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 ...

  12. Models for source term, flow, transport and dose assessment in NRC`s Iterative Performance Assessment, Phase 2

    SciTech Connect (OSTI)

    McCartin, T.; Codell, R.; Neel, R.; Ford, W.; Wescott, R.; Bradbury, J. [Nuclear Regulatory Commission, Washington, DC (United States); Sagar, B.; Walton, J. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1994-12-31T23:59:59.000Z

    The core consequence modules for the recently completed Phase 2 Iterative Performance Assessment (IPA) of the Yucca Mountain repository for high-level nuclear waste depend on models for releases from the engineered barrier system (source term), flow of liquid and gas, transport of radionuclides in the geosphere and assessment of dose to target populations. The source term model includes temperature and moisture phenomena in the near-field environment, general, pitting and crevice corrosion, contact of the waste form by water, dissolution and oxidation of the waste form, and transport of dissolved and gaseous radionuclides from the waste package by advection and diffusion. The liquid flow and transport models describe water flow through fractures and matrix in both the unsaturated and saturated zones. Models for flow of gas and transport of {sup 14}CO{sub 2} released from the engineered barrier system to the atmosphere take into account repository heat and the geothermal gradient. The dose assessment model calculates doses to a regional population and a farm family for an assumed reference biosphere in the vicinity of the repository. The Phase 2 IPA led to a number of suggestions for model improvement: (1) improve the ability of the models to include spatial and temporal variability in the parameters; (2) improve the coupling among processes, especially the effects of changing environments in the waste packages; (3) develop more mechanistic models, but abstracted for use in total system performance assessment; and (4) use more site specific parameters, especially for the dose assessments.

  13. 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

  14. A Classical Approach in Simple Nuclear Fusion Reaction 1H2 + 1H3 using Two-Dimension Granular Molecular Dynamics Model

    E-Print Network [OSTI]

    Sparisoma Viridi; Rizal Kurniadi; Abdul Waris; Yudha Satya Perkasa

    2011-09-30T23:59:59.000Z

    Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between 1H2 and 1H3 is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary 2He4 nucleus.

  15. Carbon-nitrogen bond-forming reactions in supercritical and expanded-liquid carbon dioxide media : green synthetic chemistry with multiscale reaction and phase behavior modeling

    E-Print Network [OSTI]

    Ciccolini, Rocco P

    2008-01-01T23:59:59.000Z

    The goal of this work was to develop a detailed understanding of carbon-nitrogen (C-N) bond-forming reactions of amines carried out in supercritical and expanded-liquid carbon dioxide (CO2) media. Key motivations behind ...

  16. Numerical Modeling of 90Sr and 137Cs Transport from a Spill in the B-Cell of the 324 Building, Hanford Site 300 Area

    SciTech Connect (OSTI)

    Rockhold, Mark L.; Bacon, Diana H.; Freedman, Vicky L.; Lindberg, Michael J.; Clayton, Ray E.

    2012-03-19T23:59:59.000Z

    To characterize the extent of contamination under the 324 Building, a pit was excavated on the north side of the building in 2010 by Washington Closure Hanford LLC (WCH). Horizontal closed-end steel access pipes were installed under the foundation of the building from this pit and were used for measuring temperatures and exposure rates under the B-Cell. The deployed sensors measured elevated temperatures of up to 61 C (142 F) and exposure rates of up to 8,900 R/hr. WCH suspended deactivation of the facility because it recognized that building safety systems and additional characterization data might be needed for remediation of the contaminated material. The characterization work included additional field sampling, laboratory measurements, and numerical flow and transport modeling. Laboratory measurements of sediment physical, hydraulic, and geochemical properties were performed by Pacific Northwest National Laboratory (PNNL) and others. Geochemical modeling and subsurface flow and transport modeling also were performed by PNNL to evaluate the possible extent of contamination in the unsaturated sand and gravel sediments underlying the building. Historical records suggest that the concentrated 137Cs- and 90Sr-bearing liquid wastes that were spilled in B-Cell were likely from a glass-waste repository testing program associated with the Federal Republic of Germany (FRG). Incomplete estimates of the aqueous chemical composition (no anion data provided) of the FRG waste solutions were entered into a geochemical speciation model and were charge balanced with nitrate to estimate waste composition. Additional geochemical modeling was performed to evaluate reactions of the waste stream with the concrete foundation of the building prior to the stream entering the subsurface.

  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. Tritium transport in the NuMI decay pipe region - modeling and comparison with experimental data

    SciTech Connect (OSTI)

    Hylen, J.; Plunkett, R.; /Fermilab

    2007-03-01T23:59:59.000Z

    The NuMI (Neutrinos at Main Injector) beam facility at Fermilab is designed to produce an intense beam of muon neutrinos to be sent to the MINOS underground experiment in Soudan, Minnesota. Neutrinos are created by the decay of heavier particles. In the case of NuMI, the decaying particles are created by interaction of high-energy protons in a target, creating mostly positive pions. These particles can also interact with their environment, resulting in production of a variety of short-lived radionuclides and tritium. In the NuMI beam, neutrinos are produced by 120 GeV protons from the Fermilab Main Injector accelerator which are injected into the NuMI beam line using single turn extraction. The beam line has been designed for 400 kW beam power, roughly a factor of 2 above the initial (2005-06) running conditions. Extracted protons are bent downwards at a 57mr angle towards the Soudan Laboratory. The meson production target is a 94 cm segmented graphite rod, cooled by water in stainless tubes on the top and bottom of the target. The target is followed by two magnetic horns which are pulsed to 200 kA in synchronization with the passage of the beam, producing focusing of the secondary hadron beam and its daughter neutrinos. Downstream of the second horn the meson beam is transported for 675 m in an evacuated 2 m diameter beam (''decay'') pipe. Subsequently, the residual mesons and protons are absorbed in a water cooled aluminum/steel absorber immediately downstream of the decay pipe. Some 200 m of rock further downstream ranges out all of the residual muons. During beam operations, after installation of the chiller condensate system in December 2005, the concentration of tritiated water in the MINOS sump flow of 177 gpm was around 12 pCi/ml, for a total of 0.010 pCi/day. A simple model of tritium transport and deposition via humidity has been constructed to aid in understanding how tritium reaches the sump water. The model deals with tritium transported as HTO, water in which one hydrogen atom has been replaced with tritium. Based on concepts supported by the modeling, a dehumidification system was installed during May 2006 that reduced the tritium level in the sump by a factor of two. This note is primarily concerned with tritium that was produced in the NuMI target pile, carried by air flow into the target hall and down the decay pipe passageway (where most of it was deposited). The air is exhausted through the existing air vent shaft EAV2 (Figure 1).

  19. 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.

  20. How does the mass transport in disk galaxy models influence the character of orbits?

    E-Print Network [OSTI]

    Zotos, Euaggelos E

    2015-01-01T23:59:59.000Z

    We explore the regular or chaotic nature of orbits of stars moving in the meridional (R,z) plane of an axially symmetric time-dependent disk galaxy model with a central, spherically symmetric nucleus. In particular, mass is linearly transported from the disk to the galactic nucleus, in order to mimic, in a way, the case of self-consistent interactions of an actual N-body simulation. We thus try to unveil the influence of this mass transportation on the different families of orbits of stars by monitoring how the percentage of chaotic orbits, as well as the percentages of orbits of the main regular resonant families, evolve as the galaxy develops a dense and massive nucleus in its core. The SALI method is applied to samples of orbits in order to distinguish safely between ordered and chaotic motion. In addition, a method based on the concept of spectral dynamics is used for identifying the various families of regular orbits and also for recognizing the secondary resonances that bifurcate from them. Our computat...

  1. Additional resonant contribution to the potential model for the 12C(alpha,gamma)16O reaction

    E-Print Network [OSTI]

    M. Katsuma

    2014-04-15T23:59:59.000Z

    The additional resonant contribution to the potential model is examined in $\\alpha$+$^{12}$C elastic scattering and the low-energy $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O reaction. The excitation function of elastic scattering below $E_{c.m.}= 5$ MeV seems to be reproduced by the potential model satisfactorily, and it is not profoundly disturbed by the additional resonances. The weak coupling is good enough to describe the $^{16}$O structure in the vicinity of the $\\alpha$-particle threshold, especially below $E_{c.m.}= 8$ MeV, corresponding to the excitation energy $E_x \\approx 15$ MeV. The additional resonances give the complement of the astrophysical $S$-factors from the simple potential model. The $S$-factor of $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O at $E_{c.m.}=300$ keV is dominated by the $E$2 transition, which is enhanced by the subthreshold 2$^+_1$ state at $E_x= 6.92$ MeV. The contribution from the subthreshold 1$^-_1$ state at $E_x= 7.12$ MeV is predicted to be small. The additional resonances do not give the large contribution to the thermonuclear reaction rates of $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O at helium burning temperatures.

  2. Energy Dependence of Energy Partition in Products of Direct Reactions: Crossed?Beam Studies and a New Model

    E-Print Network [OSTI]

    Hierl, Peter M.; Herman, Z.; Kerstetter, J.; Wolfgang, R.

    1968-01-01T23:59:59.000Z

    and R. E. Merrifield (unpublished). Energy Dependence of Energy Partition in Products of Direct Reactions: Crossed Beam Studies and aNew Model P. HIERL, Z. HERMAN,* J. KERSTETTER, AND R. WOLFGANG Department of Chemistry, Yale University, New Haven.... (If position of maximum intensity in c.m. system were plotted, a somewhat higher intercept Qo would result.) modes of the products, and on the dependence of this on initial kinetic energy. Results on the systems Ar++D~ArD++D, and Ar...

  3. On the electrodynamic model of ultra-relativistic laser-plasma interactions caused by radiation reaction effects

    SciTech Connect (OSTI)

    Bashinov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation)] [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation); Kim, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation) [Institute of Applied Physics, Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation); University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation)

    2013-11-15T23:59:59.000Z

    A simple electrodynamic model is developed to define plasma-field structures in self-consistent ultra-relativistic laser-plasma interactions when the radiation reaction effects come into play. An exact analysis of a circularly polarized laser interacting with plasmas is presented. We define fundamental notions, such as nonlinear dielectric permittivity, ponderomotive and dissipative forces acting in a plasma. Plasma-field structures arising during the ultra-relativisitc interactions are also calculated. Based on these solutions, we show that about 50% of laser energy can be converted into gamma-rays in the optimal conditions of laser-foil interaction.

  4. ATOMIC-LEVEL MODELING OF CO2 DISPOSAL AS A CARBONATE MINERAL: A SYNERGETIC APPROACH TO OPTIMIZING REACTION PROCESS DESIGN

    SciTech Connect (OSTI)

    A.V.G. Chizmeshya; M.J. McKelvy; J.B. Adams

    2001-11-01T23:59:59.000Z

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Permanent and safe methods for CO{sub 2} capture and disposal/storage need to be developed. Mineralization of stationary-source CO{sub 2} emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar hydroxide mineral carbonation is a leading process candidate, which generates the stable naturally occurring mineral magnesite (MgCO{sub 3}) and water. Key to process cost and viability are the carbonation reaction rate and its degree of completion. This process, which involves simultaneous dehydroxylation and carbonation is very promising, but far from optimized. In order to optimize the dehydroxylation/carbonation process, an atomic-level understanding of the mechanisms involved is needed. In this investigation Mg(OH){sub 2} was selected as a model Mg-rich lamellar hydrocide carbonation feedstock material due to its chemical and structural simplicity. Since Mg(OH){sub 2} dehydroxylation is intimately associated with the carbonation process, its mechanisms are also of direct interest in understanding and optimizing the process. The aim of the current innovative concepts project is to develop a specialized advanced computational methodology to complement the ongoing experimental inquiry of the atomic level processes involved in CO{sub 2} mineral sequestration. The ultimate goal is to integrate the insights provided by detailed predictive simulations with the data obtained from optical microscopy, FESEM, ion beam analysis, SIMS, TGA, Raman, XRD, and C and H elemental analysis. The modeling studies are specifically designed to enhance the synergism with, and complement the analysis of, existing mineral-CO{sub 2} reaction process studies being carried out under DOE UCR Grant DE-FG2698-FT40112. Direct contact between the simulations and the experimental measurements is provided by computing, from first principles, the equilibrium structures, elastic, optical, and vibrational properties of Mg(OH){sub 2} (brucite), MgO (periclase), MgCO{sub 3} (magnesite), as well as the energetics of the dehydroxylation reaction (Mg(OH){sub 2} {yields} MgO + H{sub 2}O), and the reactivity of CO{sub 2} with MgO and Mg(OH){sub 2}. From these calculations, thermodynamic characteristics of the reaction conditions can be inferred. This kind of information, when integrated with the atomic level data obtained from experimental gas-solid dehydroxylation/carbonation studies, will be used to design optimized reaction processes leading to the practical and cost-effective sequestration of CO{sub 2} in mineral form.

  5. Mechanistic modeling of increased oxygen transport using functionalized magnetic fluids in bioreactors

    E-Print Network [OSTI]

    Oll Pocurull, Bernat

    2007-01-01T23:59:59.000Z

    Absorption of gases into a liquid is of crucial importance to multiphase reactions because diffusion of a sparingly soluble gas across a gas-liquid interface generally limits the relevant reaction rates. Pertinent examples ...

  6. 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.

  7. 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 ...

  8. 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...

  9. 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 countrys regionally heterogeneous transport system. In order to simulate these impacts, transport sector detail is added to a multi-sector, ...

  10. On the modeling and simulation of reaction-transfer dynamics in semiconductor-electrolyte solar cells

    E-Print Network [OSTI]

    Ren, Kui

    -performance semiconductor-liquid junction solar cells. We propose in this work a macroscopic mathematical model, a sys- tem-liquid junction, solar cell simulation, naso-scale device modeling. 1 Introduction The mathematical modeling by the increasing need of simulation tools for designing efficient solar cells to harvest sunlight for clean energy

  11. 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.

  12. ECRH and transport modeling in tandem mirrors and divertor physics. Task II. Annual progress report on fusion plasma theory, January 1-September 31, 1982

    SciTech Connect (OSTI)

    Emmert, G A

    1982-08-01T23:59:59.000Z

    A summary of work during this period is given for the following: ecrh and transport modeling in tandem mirrors and divertor physics. (MOW)

  13. 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.

  14. 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.

  15. Influence of Transport Variables on Isospin Transport Ratios

    E-Print Network [OSTI]

    Coupland, D D S; Tsang, M B; Danielewicz, P; Zhang, Yingxun

    2011-01-01T23:59:59.000Z

    The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscaler mean field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending upon whether they are computed using the isospin asymmetry of either the residue or of a...

  16. 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

  17. Modeling Complex Organic Molecules in dense regions: Eley-Rideal and complex induced reaction

    E-Print Network [OSTI]

    Ruaud, M; Hickson, K M; Gratier, P; Hersant, F; Wakelam, V

    2014-01-01T23:59:59.000Z

    Recent observations have revealed the existence of Complex Organic Molecules (COMs) in cold dense cores and prestellar cores. The presence of these molecules in such cold conditions is not well understood and remains a matter of debate since the previously proposed "warm- up" scenario cannot explain these observations. In this article, we study the effect of Eley- Rideal and complex induced reaction mechanisms of gas-phase carbon atoms with the main ice components of dust grains on the formation of COMs in cold and dense regions. Based on recent experiments we use a low value for the chemical desorption efficiency (which was previously invoked to explain the observed COM abundances). We show that our introduced mechanisms are efficient enough to produce a large amount of complex organic molecules in the gas-phase at temperatures as low as 10K.

  18. A model for enhanced fusion reaction in a solid matrix of metal deuterides

    E-Print Network [OSTI]

    K. P. Sinha; A. Meulenberg

    2009-01-16T23:59:59.000Z

    Our study shows that the cross-section for fusion improves considerably if d-d pairs are located in linear (one-dimensional) chainlets or line defects. Such non-equilibrium defects can exist only in a solid matrix. Further, solids harbor lattice vibrational modes (quanta, phonons) whose longitudinal-optical modes interact strongly with electrons and ions. One such interaction, resulting in potential inversion, causes localization of electron pairs on deuterons. Thus, we have attraction of D+ D- pairs and strong screening of the nuclear repulsion due to these local electron pairs (local charged bosons: acronym, lochons). This attraction and strong coupling permits low-energy deuterons to approach close enough to alter the standard equations used to define nuclear-interaction cross-sections. These altered equations not only predict that low-energy-nuclear reactions (LENR) of D+ D- (and H+ H-) pairs are possible, they predict that they are probable.

  19. A model for enhanced fusion reaction in a solid matrix of metal deuterides

    E-Print Network [OSTI]

    Sinha, K P

    2009-01-01T23:59:59.000Z

    Our study shows that the cross-section for fusion improves considerably if d-d pairs are located in linear (one-dimensional) chainlets or line defects. Such non-equilibrium defects can exist only in a solid matrix. Further, solids harbor lattice vibrational modes (quanta, phonons) whose longitudinal-optical modes interact strongly with electrons and ions. One such interaction, resulting in potential inversion, causes localization of electron pairs on deuterons. Thus, we have attraction of D+ D- pairs and strong screening of the nuclear repulsion due to these local electron pairs (local charged bosons: acronym, lochons). This attraction and strong coupling permits low-energy deuterons to approach close enough to alter the standard equations used to define nuclear-interaction cross-sections. These altered equations not only predict that low-energy-nuclear reactions (LENR) of D+ D- (and H+ H-) pairs are possible, they predict that they are probable.

  20. Chemical Accelerator Studies of Isotope Effects on Collision Dynamics of IonMolecule Reactions: Elaboration of a Model for Direct Reactions

    E-Print Network [OSTI]

    Hierl, Peter M.; Herman, Z.; Wolfgang, R.

    1970-01-01T23:59:59.000Z

    Crossed?beam studies on isotopic variants of the reaction Ar+?+?H2?ArH+ are reported. Both velocity and angular distributions of the ionic product as a function of initial translational energy, down to 0.1 eV (center of ...

  1. The H2O2+OH ? HO2+H2O reaction in aqueous solution from a charge-dependent continuum model of solvation

    SciTech Connect (OSTI)

    Ginovska, Bojana; Camaioni, Donald M.; Dupuis, Michel

    2008-07-07T23:59:59.000Z

    We applied our recently developed protocol of the conductor-like continuum model of solvation to describe the title reaction in aqueous solution. The model has the unique feature of the molecular cavity being dependent on the atomic charges in the solute, and can be extended naturally to transition states and reaction pathways. It was used to calculate the reaction energetics and reaction rate in solution for the title reaction. The rate of reaction calculated using canonical variational transition state theory CVT in the context of the equilibrium solvation path (ESP) approximation, and including correction for tunneling through the small curvature approximation (SCT) was found to be 3.6 106 M-1 s-1, in very good agreement with experiment, These results suggest that the present protocol of the conductor-like continuum model of solvation with the charge-dependent cavity definition captures accurately the solvation effects at transition states and allows for quantitative estimates of reaction rates in solutions. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program. The Pacific Northwest National Laboratory is operated by Battelle for DOE.

  2. 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.

  3. Recent Site-Wide Transport Modeling Related to the Carbon Tetrachloride Plume at the Hanford Site

    SciTech Connect (OSTI)

    Bergeron, Marcel P.; Cole, C R.

    2005-11-01T23:59:59.000Z

    Carbon tetrachloride transport in the unconfined aquifer system at the Hanford Site has been the subject of follow-on studies since the Carbon Tetrachloride Innovative Treatment Remediation Demonstration (ITRD) Program was completed in FY 2002. These scoping analyses were undertaken to provide support for strategic planning and guidance for the more robust modeling needed to obtain a final record of decision (ROD) for the carbon tetrachloride plume in the 200 West Area. This report documents the technical approach and the results of these follow-on, site-wide scale-modeling efforts. The existing site-wide groundwater model was used in this effort. The work extended that performed as part of the ITRD modeling study in which a 200 West Area scale submodel was developed to examine arrival concentrations at an arbitrary boundary between the 200 E and 200 W areas. These scoping analyses extended the analysis to predict the arrival of the carbon tetrachloride plume at the Columbia River. The results of these analyses illustrate the importance of developing field-scale estimates of natural attenuation parameters, abiotic degradation rate and soil/water equilibrium sorption coefficient, for carbon tetrachloride. With these parameters set to zero, carbon tetrachloride concentrations will exceed the compliance limit of 5 ?g/L outside the 200 Area Plateau Waste Management Area, and the aquifer source loading and area of the aquifer affected will continue to grow until arrival rates of carbon tetrachloride equal source release rates, estimated at 33 kg/yr. Results of this scoping analysis show that the natural attenuation parameters are critical in predicting the future movement of carbon tetrachloride from the 200 West Area. Results also show the significant change in predictions between continual source release from the vadose zone and complete source removal.

  4. 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.

  5. Pb-Pb collisions at root s(NN)=2.76 TeV in a multiphase transport model

    E-Print Network [OSTI]

    Xu, Jun; Ko, Che Ming.

    2011-01-01T23:59:59.000Z

    The multiplicity and elliptic flow of charged particles produced in Pb-Pb collisions at center of mass energy root s(NN) = 2.76 TeV from the Large Hadron Collider are studied in a multiphase transport (AMPT) model. With the standard parameters...

  6. PHYSICAL REVIEW B 88, 144305 (2013) Two-channel model for nonequilibrium thermal transport in pump-probe experiments

    E-Print Network [OSTI]

    Cahill, David G.

    150 nm of the Al/Si0.99Ge0.01 interface. The extra thermal resistance in this region is a result. INTRODUCTION The magnitude of a material's thermal conductivity and spe- cific heat is determinedPHYSICAL REVIEW B 88, 144305 (2013) Two-channel model for nonequilibrium thermal transport in pump

  7. A fundamental study of model fuel conversion reactions in sub and supercritical water

    E-Print Network [OSTI]

    Lachance, Russell Philip

    2005-01-01T23:59:59.000Z

    Model reactants under hydrothermal conditions were examined to improve our understanding of chemical transformations in this high temperature and pressure environment. Results have a direct impact on present and future ...

  8. NUMERICAL MODELING OF CONTAMINANT TRANSPORT IN FRACTURED POROUS MEDIA USING MIXED FINITE ELEMENT AND FINITE VOLUME METHODS

    SciTech Connect (OSTI)

    Taylor, G.; Dong, C.; Sun, S.

    2010-03-18T23:59:59.000Z

    A mathematical model for contaminant species passing through fractured porous media is presented. In the numerical model, we combine two locally conservative methods, i.e. mixed finite element (MFE) and the finite volume methods. Adaptive triangle mesh is used for effective treatment of the fractures. A hybrid MFE method is employed to provide an accurate approximation of velocities field for both the fractures and matrix which are crucial to the convection part of the transport equation. The finite volume method and the standard MFE method are used to approximate the convection and dispersion terms respectively. The model is used to investigate the interaction of adsorption with transport and to extract information on effective adsorption distribution coefficients. Numerical examples in different fractured media illustrate the robustness and efficiency of the proposed numerical model.

  9. Enabling HCCI modeling: The RIOT/CMCS Web Service for Automatic Reaction Mechanism Reduction

    SciTech Connect (OSTI)

    Oluwole, O; Pitz, W J; Schuchardt, K; Rahn, L A; Green, Jr., W H; Leahy, D; Pancerella, C; Sj?berg, M; Dec, J

    2005-12-12T23:59:59.000Z

    New approaches are being developed to facilitate multidisciplinary collaborative research of Homogeneous Charge Compression Ignition (HCCI) combustion processes. In this paper, collaborative sharing of the Range Identification and Optimization Toolkit (RIOT) and related data and models is discussed. RIOT is a developmental approach to reduce the computational complexity of detailed chemical kinetic mechanisms, enabling their use in modeling kinetically-controlled combustion applications such as HCCI. These approaches are being developed and piloted as a part of the Collaboratory for Multiscale Chemical Sciences (CMCS) project. The capabilities of the RIOT code are shared through a portlet in the CMCS portal that allows easy specification and processing of RIOT inputs, remote execution of RIOT, tracking of data pedigree and translation of RIOT outputs (such as the reduced model) to a table view and to the commonly-used CHEMKIN mechanism format. The reduced model is thus immediately ready to be used for more efficient simulation of the chemically reacting system of interest. This effort is motivated by the need to improve computational efficiency in modeling HCCI systems. Preliminary use of the web service to obtain reduced models for this application has yielded computational speedup factors of up to 20 as presented in this paper.

  10. THE INFLUENCE OF UNCERTAINTIES IN THE {sup 15}O({alpha}, {gamma}){sup 19}Ne REACTION RATE ON MODELS OF TYPE I X-RAY BURSTS

    SciTech Connect (OSTI)

    Davids, Barry [TRIUMF, Vancouver, BC V6T 2A3 (Canada); Cyburt, Richard H. [Joint Institute for Nuclear Astrophysics and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI (United States); Jose, Jordi [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya and Institut d'Estudis Espacials de Catalunya, Barcelona (Spain); Mythili, Subramanian [Physics Department, George Mason University, Fairfax, VA (United States)

    2011-07-01T23:59:59.000Z

    We present a Monte Carlo calculation of the astrophysical rate of the {sup 15}O({alpha}, {gamma}){sup 19}Ne reaction based on an evaluation of published experimental data. By considering the likelihood distributions of individual resonance parameters derived from measurements, estimates of upper and lower limits on the reaction rate at the 99.73% confidence level are derived in addition to the recommended, median value. These three reaction rates are used as input for three separate calculations of Type I X-ray bursts (XRBs) using spherically symmetric, hydrodynamic simulations of an accreting neutron star. In this way the influence of the {sup 15}O({alpha}, {gamma}){sup 19}Ne reaction rate on the peak luminosity, recurrence time, and associated nucleosynthesis in models of Type I XRBs is studied. Contrary to previous findings, no substantial effect on any of these quantities is observed in a sequence of four bursts when varying the reaction rate between its lower and upper limits. Rather, the differences in these quantities are comparable to the burst-to-burst variations with a fixed reaction rate, indicating that uncertainties in the {sup 15}O({alpha}, {gamma}){sup 19}Ne reaction rate do not strongly affect the predictions of this Type I XRB model.

  11. Model Development and Analysis of the Fate and Transport of Water...

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

    study reflects the project's preliminary effort at simulating the fluid flow and heat transport processes, before treating the fully coupled thermal-mechanical-hydrologic-chemical...

  12. Modelling of reactive gas transport in unsaturated soil. A coupled thermo-hydro-chemical-mechanical approach.

    E-Print Network [OSTI]

    Masum, Shakil Al

    2012-01-01T23:59:59.000Z

    ??This thesis presents the development of a reactive gas transport equation under coupled framework of thermal, hydraulic, chemical and mechanical (THCM) behaviour of variably saturated (more)

  13. Semiclassical Distorted Wave Model Analysis of Backward Proton Emission from $(p,p^{\\prime}x)$ Reactions at Intermediate Energies

    E-Print Network [OSTI]

    M. K. Gaidarov; Y. Watanabe; K. Ogata; M. Kohno; M. Kawai; A. N. Antonov

    2003-07-28T23:59:59.000Z

    A semiclassical distorted wave (SCDW) model with Wigner transform of one-body density matrix is presented for multistep direct $(p,p^{\\prime}x)$ reactions to the continuum. The model uses Wigner distribution functions obtained in methods which include nucleon-nucleon correlations to a different extent, as well as Woods-Saxon (WS) single-particle wave function. The higher momentum components of target nucleons that play a crucial role in reproducing the high-energy part of the backward proton spectra are properly taken into account. This SCDW model is applied to analyses of multistep direct processes in $^{12}$C$(p,p^{\\prime}x)$, $^{40}$Ca$(p,p^{\\prime}x)$ and $^{90}$Zr$(p,p^{\\prime}x)$ in the incident energy range of 150--392 MeV. The double differential cross sections are calculated up to three-step processes. The calculated angular distributions are in good agreement with the experimental data, in particular at backward angles where the previous SCDW calculations with the WS single-particle wave function showed large underestimation. It is found that the result with the Wigner distribution function based on the coherent density fluctuation model provides overall better agreement with the experimental data over the whole emission energies.

  14. Direct Insertion of MODIS Radiances in a Global Aerosol Transport Model CLARK WEAVER,* ARLINDO DA SILVA, MIAN CHIN,# PAUL GINOUX,@ OLEG DUBOVIK,&,@@

    E-Print Network [OSTI]

    Chin, Mian

    is directly inserted into the Goddard Chemistry and Aerosol Radiation Transport model (GOCART), which aerosol radiative forcing in the thermody- namic equation of GCMs, 3) to account for the reduc- tionDirect Insertion of MODIS Radiances in a Global Aerosol Transport Model CLARK WEAVER,* ARLINDO DA

  15. 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

  16. Laboratory Measurements of Wave Forcing and Reactions on a Model Submerged Mesh Breakwater

    E-Print Network [OSTI]

    Knoll, Alex Baxter

    2014-07-30T23:59:59.000Z

    The purpose of this thesis is to design the test setup, perform the model tests, and process the data to find the wave forces on a submerged breakwater. Breakwaters are coastal protection structures used to help prevent the erosion of the shoreline...

  17. Cahn-Hilliard Reaction Model for Isotropic Li-ion Battery Particles Yi Zeng1, Martin Z. Bazant1,2

    E-Print Network [OSTI]

    Bazant, Martin Z.

    Cahn-Hilliard Reaction Model for Isotropic Li-ion Battery Particles Yi Zeng1, Martin Z. Bazant1,2 1 particle. This general approach extends previous Li-ion battery models, which either neglect phase theory for Li-ion batteries [13, 18] with Butler-Volmer kinetics and concentration depen- dent

  18. On the Sensitivity of Atmospheric Model Implied Ocean Heat Transport to the Dominant Terms of the Surface Energy Balance

    SciTech Connect (OSTI)

    Gleckler, P J

    2004-11-03T23:59:59.000Z

    The oceanic meridional heat transport (T{sub o}) implied by an atmospheric General Circulation Model (GCM) can help evaluate a model's readiness for coupling with an ocean GCM. In this study we examine the T{sub o} from benchmark experiments of the Atmospheric Model Intercomparison Project, and evaluate the sensitivity of T{sub o} to the dominant terms of the surface energy balance. The implied global ocean TO in the Southern Hemisphere of many models is equatorward, contrary to most observationally-based estimates. By constructing a hybrid (model corrected by observations) T{sub o}, an earlier study demonstrated that the implied heat transport is critically sensitive to the simulated shortwave cloud radiative effects, which have been argued to be principally responsible for the Southern Hemisphere problem. Systematic evaluation of one model in a later study suggested that the implied T{sub o} could be equally as sensitive to a model's ocean surface latent heat flux. In this study we revisit the problem with more recent simulations, making use of estimates of ocean surface fluxes to construct two additional hybrid calculations. The results of the present study demonstrate that indeed the implied T{sub o} of an atmospheric model is very sensitive to problems in not only the surface net shortwave, but the latent heat flux as well. Many models underestimate the shortwave radiation reaching the surface in the low latitudes, and overestimate the latent heat flux in the same region. The additional hybrid transport calculations introduced here could become useful model diagnostic tests as estimates of implied ocean surface fluxes are improved.

  19. Wave transport for a scalar model of the Love waves Guillaume Bal Leonid Ryzhik y

    E-Print Network [OSTI]

    Ryzhik, Lenya

    of the wavelength. The transport equation accounts for the multiple scattering of the Love waves analyzed using radiative transfer equations for more than thirty years [5, 6, 7, 8, 14]. A systematic and e?cient way to obtain transport equations is presented in [16, 18]. The mathematics involved in this process

  20. Wave transport for a scalar model of the Love waves Guillaume Bal Leonid Ryzhik \\Lambda

    E-Print Network [OSTI]

    Bal, Guillaume

    of the wavelength. The transport equation accounts for the multiple scattering of the Love waves using radiative transfer equations for more than thirty years [5, 6, 7, 8, 14]. A systematic and efficient way to obtain transport equations is presented in [16, 18]. The mathematics involved

  1. 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

  2. Numerical modeling of deep groundwater flow and heat transport in the Williston Basin

    SciTech Connect (OSTI)

    Garven, G.; Vigrass, L.

    1985-01-01T23:59:59.000Z

    A numerical modeling approach has been used to evaluate quantitatively the effects of fluid flow on contemporary heat flow in an intracratonic basin. The authors have selected the Williston basin for this hydrodynamic study because of the opportunity it presents to assess the relation of deep groundwater flow to basin geothermics and the associated features of diagenesis and petroleum accumulation. The finite element method is used to solve the coupled equations of fluid flow and heat transport in two-dimensional sections of the basin. Both the fluid- and heat-flow regime are assumed to be at steady state, and the fluid flow is driven primarily by the water-table relief which is taken to be a subdued replica of land-surface topography. Buoyancy forces may also affect flow through fluid density gradients created by temperature and salinity effects. Three southwest-northwest oriented sections across the basin were modeled using available and estimated parameter data. The predicted flow patterns are most strongly affected by the topography, but the Devonian salt unit and Cretaceous shale unit exert some control. Cross-formational flow is especially important near the downdip, solution edge of the salt beds. Flow rates rarely exceed 0.5 m/year in the deep-central part of the basin, yet there does exist a marked effect on heat flow, albeit subdued by the blanket effect of the low-permeability Cretaceous shales. The regional effect of the topography-driven flow system is reflected in present-day salinity patterns and heat-flow data.

  3. A Nonlinear Model of a Quantum Minisuperspace System with Back Reaction

    E-Print Network [OSTI]

    Marcos Rosenbaum; Michael P. Ryan; Sukanya Sinha

    1992-12-16T23:59:59.000Z

    We consider the quantum evolution of the space-independent mode of a $\\lambda {\\phi}^4$ theory as a minisuperspace in the space of all $\\phi$. The motion of the wave packet in the minisuperspace is then compared to the motion of a wave packet in a larger minisuperspace consisting of the original minisuperspace plus one space-dependent mode. By comparing the motion of the two packets we develop criteria that tell us when the quantum evolution in the space-independent minisuperspace gives us useful information about the true evolution in the larger minisuperspace. These criteria serve as a toy model for similar(but much more complex) criteria that will tell us whether or when quantized gravitational minisuperspaces can possibly give any useful information about quantum gravity.

  4. Phase transitions in a reaction-diffusion model on a line with boundaries

    SciTech Connect (OSTI)

    Khorrami, Mohammad, E-mail: mamwad@mailaps.org; Aghamohammadi, Amir, E-mail: mohamadi@alzahra.ac.ir [Department of Physics, Alzahra University, Tehran 19938-93973 (Iran, Islamic Republic of)] [Department of Physics, Alzahra University, Tehran 19938-93973 (Iran, Islamic Republic of)

    2014-03-15T23:59:59.000Z

    A one-dimensional model on a line of length L is investigated, which involves particle diffusion as well as single particle annihilation. There are also creation and annihilation at the boundaries. The static and dynamical behaviors of the system are studied. It is seen that the system could exhibit a dynamical phase transition. For small drift velocities, the relaxation time does not depend on the absorption rates at the boundaries. This is the fast phase. For large velocities, the smaller of the absorption rates at boundaries enter the relaxation rate and makes it longer. This is the slow phase. Finally, the effect of a random particle creation in the bulk is also investigated.

  5. 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.

  6. 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.

  7. 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 ...

  8. 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.

  9. 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.

  10. 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

  11. 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 ...

  12. 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 M. 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.

  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. A mixed SOC-turbulence model for nonlocal transport and Levy-fractional Fokker-Planck equation

    E-Print Network [OSTI]

    Alexander V. Milovanov; Jens Juul Rasmussen

    2014-03-24T23:59:59.000Z

    The phenomena of nonlocal transport in magnetically confined plasma are theoretically analyzed. A hybrid model is proposed, which brings together the notion of inverse energy cascade, typical of drift-wave- and two-dimensional fluid turbulence, and the ideas of avalanching behavior, associable with self-organized critical (SOC) behavior. Using statistical arguments, it is shown that an amplification mechanism is needed to introduce nonlocality into dynamics. We obtain a consistent derivation of nonlocal Fokker-Planck equation with space-fractional derivatives from a stochastic Markov process with the transition probabilities defined in reciprocal space. The hybrid model observes the Sparre Andersen universality and defines a new universality class of SOC.

  16. 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.

  17. 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.

  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. 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.

  20. Transportation Routing Analysis Geographic Information System (TRAGIS)

    E-Print Network [OSTI]

    Transportation Routing Analysis Geographic Information System (TRAGIS) Model and Network Databases The Transportation Routing Analysis Geographic Information System (TRAGIS) model is a geographic information system tool for modeling transportation routing. TRAGIS offers numerous options for route calculation

  1. 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.

  2. 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

  3. Naturally fractured reservoirs: Optimized E and P strategies using a reaction-transport-mechanical simulator in an integrated approach. Annual report, 1996--1997

    SciTech Connect (OSTI)

    Hoak, T.; Jenkins, R. [Science Applications International Corp., McLean, VA (United States); Ortoleva, P.; Ozkan, G.; Shebl, M.; Sibo, W.; Tuncay, K. [Laboratory for Computational Geodynamics (United States); Sundberg, K. [Phillips Petroleum Company (United States)

    1998-07-01T23:59:59.000Z

    The methodology and results of this project are being tested using the Andector-Goldsmith Field in the Permian Basin, West Texas. The study area includes the Central Basin Platform and the Midland Basin. The Andector-Goldsmith Field lies at the juncture of these two zones in the greater West Texas Permian Basin. Although the modeling is being conducted in this area, the results have widespread applicability to other fractured carbonate and other reservoirs throughout the world.

  4. 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.

  5. 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.

  6. 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.

  7. Correlation between Median Household Income and LEED Sustainable Site Criteria for Public Transportation Access and a Regression Model Predicting Appraised Unit Value of Unimproved Parcels in Houston, Texas

    E-Print Network [OSTI]

    Ji, Qundi

    2010-07-14T23:59:59.000Z

    transportation access. Moreover, the regression model for predicting appraised unit value of a parcel suggested that the coefficient of Number of Light Rail Stations was positive, while the coefficient of Number of Bus Stops was negative. This result contradicted...

  8. Dynamic Monte-Carlo modeling of hydrogen isotope reactivediffusive transport in porous graphite

    E-Print Network [OSTI]

    Nordlund, Kai

    by voids which are typically a fraction of a microm- eter. The granules consist of graphitic micro-crystal- lites of size 10­100 nm separated by micro-voids which are typically 1 nm (Fig. 1) [1­4]. These sub chemical reactions to form hydrocarbons or recombine to form hydro- gen molecules which can then diffuse

  9. 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

  10. 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

  11. 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...

  12. 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...

  13. Modeling the Hydrogeochemical Transport of Radionuclides through Engineered Barriers System in the Proposed LLW Disposal Site of Taiwan - 12082

    SciTech Connect (OSTI)

    Lin, Wen-Sheng [Hydrotech Research Institute, National Taiwan University, Taipei, Taiwan (China); Liu, Chen-Wuing; Tsao, Jui-Hsuan [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan (China); Li, Ming-Hsu [Institute of Hydrological and Oceanic Sciences, National Central University, Jhongli, Taiwan (China)

    2012-07-01T23:59:59.000Z

    A proposed site for final disposal of low-level radioactive waste located in Daren Township of Taitung County along the southeastern coast has been on the selected list in Taiwan. The geology of the Daren site consists of argillite and meta-sedimentary rocks. A mined cavern design with a tunnel system of 500 m below the surface is proposed. Concrete is used as the main confinement material for the engineered barrier. To investigate the hydrogeochemical transport of radionuclides through engineered barriers system, HYDROGEOCHEM5.0 model was applied to simulate the complex chemical interactions among radionuclides, the cement minerals of the concrete, groundwater flow, and transport in the proposed site. The simulation results showed that the engineered barriers system with the side ditch efficiently drained the ground water and lowered the concentration of the concrete degradation induced species (e.g., hydrogen ion, sulfate, and chloride). The velocity of groundwater observed at side ditch gradually decreased with time due to the fouling of pore space by the mineral formation of ettringite and thaumasite. The short half-life of Co-60, Sr-90 and Cs-137 significantly reduced the concentrations, whereas the long half-life of I-129(1.57x10{sup 7} years) and Am-241(432 years) remain stable concentrations at the interface of waste canister and concrete barrier after 300 years. The mineral saturation index (SI) was much less than zero due to the low aqueous concentration of radionuclide, so that the precipitation formation of Co-60, Sr-90, I-129, Cs-137 and Am-241 related minerals were not found. The effect of adsorption/desorption (i.e., surface complexation model) could be a crucial geochemical mechanism for the modeling of liquid-solid phase behavior of radionuclide in geochemically dynamic environments. Moreover, the development of advanced numerical models that are coupled with hydrogeochemical transport and dose assessment of radionuclide is required in the future. (authors)

  14. Influence of Transport Variables on Isospin Transport Ratios

    E-Print Network [OSTI]

    D. D. S. Coupland; W. G. Lynch; M. B. Tsang; P. Danielewicz; Yingxun Zhang

    2011-07-19T23:59:59.000Z

    The symmetry energy in the nuclear equation of state affects many aspects of nuclear astrophysics, nuclear structure, and nuclear reactions. Recent constraints from heavy ion collisions, including isospin diffusion observables, have started to put constraints on the symmetry energy below nuclear saturation density, but these constraints depend on the employed transport model and input physics other than the symmetry energy. To understand these dependencies, we study the influence of the symmetry energy, isoscaler mean field compressibility and momentum dependence, in-medium nucleon-nucleon cross sections, and light cluster production on isospin diffusion within the pBUU transport code. In addition to the symmetry energy, several uncertain issues strongly affect isospin diffusion, most notably the cross sections and cluster production. In addition, there is a difference in the calculated isospin transport ratios, depending upon whether they are computed using the isospin asymmetry of either the residue or of all forward moving fragments. Measurements that compare the isospin transport ratios of these two quantities would help place constraints on the input physics, such as the density dependence of the symmetry energy.

  15. Modeling Groundwater Flow and Transport of Radionuclides at Amchitka Island's Underground Nuclear Tests: Milrow, Long Shot, and Cannikin

    SciTech Connect (OSTI)

    Ahmed Hassan; Karl Pohlmann; Jenny Chapman

    2002-11-19T23:59:59.000Z

    Since 1963, all United States nuclear tests have been conducted underground. A consequence of this testing has been the deposition of large amounts of radioactive material in the subsurface, sometimes in direct contact with groundwater. The majority of this testing occurred on the Nevada Test Site (NTS), but a limited number of experiments were conducted in other locations. One of these locations, Amchitka Island, Alaska is the subject of this report. Three underground nuclear tests were conducted on Amchitka Island. Long Shot was an 80-kiloton-yield test conducted at a depth of 700 meters (m) on October 29, 1965 (DOE, 2000). Milrow had an announced yield of about 1,000 kilotons, and was detonated at a depth of 1,220 m on October 2, 1969. Cannikin had an announced yield less than 5,000 kilotons, and was conducted at a depth of 1,790 m on November 6, 1971. The purpose of this work is to provide a portion of the information needed to conduct a human-health risk assessment of the potential hazard posed by the three underground nuclear tests on Amchitka Island. Specifically, the focus of this work is the subsurface transport portion, including the release of radionuclides from the underground cavities and their movement through the groundwater system to the point where they seep out of the ocean floor and into the marine environment. This requires a conceptual model of groundwater flow on the island using geologic, hydrologic, and chemical information, a numerical model for groundwater flow, a conceptual model of contaminant release and transport properties from the nuclear test cavities, and a numerical model for contaminant transport. Needed for the risk assessment are estimates of the quantity of radionuclides (in terms of mass flux) from the underground tests on Amchitka that could discharge to the ocean, the time of possible discharge, and the location in terms of distance from shoreline. The radionuclide data presented here are all reported in terms of normalized masses to avoid presenting classified information. As only linear processes are modeled, the results can be readily scaled by the true classified masses for use in the risk assessment. The modeling timeframe for the risk assessment was set at 1,000 years, though some calculations are extended to 2,000 years. This first section of the report endeavors to orient the reader with the environment of Amchitka and the specifics of the underground nuclear tests. Of prime importance are the geologic and hydrologic conditions of the subsurface. A conceptual model for groundwater flow beneath the island is then developed and paired with an appropriate numerical modeling approach in section 2. The parameters needed for the model, supporting data for them, and data uncertainties are discussed at length. The calibration of the three flow models (one for each test) is then presented. At this point the conceptual radionuclide transport model is introduced and its numerical approach described in section 3. Again, the transport parameters and their supporting data and uncertainties are the focus. With all of the processes and parameters in place, the first major modeling phase can be discussed in section 4. In this phase, a parametric uncertainty analysis is performed to determine the sensitivity of the transport modeling results to the uncertainties present in the parameters. This analysis is motivated by the recognition of substantial uncertainty in the subsurface conditions on the island and the need to incorporate that uncertainty into the modeling. The conclusion of the first phase determines the parameters to hold as uncertain through the main flow and transport modeling. This second, main phase of modeling is presented in section 5, with the contaminant breakthrough behavior of each test site addressed. This is followed by a sensitivity analysis in section 6, regarding the importance of additional processes that could not be supported in the main modeling effort due to lack of data. Finally, the results for the individual sites are compared, the sensitivities discussed,

  16. Dynamic Incompressible Navier-Stokes Model of Catalytic Converter in 1-D Including Fundamental Oxidation Reaction Rate Expressions

    E-Print Network [OSTI]

    Loya, Sudarshan Kedarnath

    2011-12-31T23:59:59.000Z

    , this work includes the history of the fundamental reactions of automotive catalysts including carbon monoxide (CO), hydrogen (H2) and nitric oxide (NO) oxidation on a widely used material formulation (platinum catalyst on alumina washcoat). A detailed report...

  17. Modeling Tritium Transport in PbLi Breeder Blankets Under Steady State

    SciTech Connect (OSTI)

    H. Zhang; A. Ying; M. Abdou; B. Merrill

    2011-08-01T23:59:59.000Z

    Tritium behavior in the breeder/coolant plays a crucial role in keeping the tritium loss under an allowable limit and realizing high tritium recovery efficiency. In this paper, progress toward the development of a comprehensive 3D predictive capability is discussed and presented. The sequence of transport processes leading to tritium release includes diffusion and convection through the PbLi, transfer across the liquid/solid interface, diffusion of atomic tritium through the structure, and dissolution-recombination at the solid/gas interface. Numerical simulation of the coupled individual physics phenomena of tritium transport is performed for DCLL/HCLL type breeder blankets under realistic reactor-like conditions in this paper. Tritium concentration and permeation are presented and the MHD effects are evaluated. Preliminary results shows that the MHD velocity profile has the significant effect in preventing tritium permeation due to the higher convection effects near the wall.

  18. 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.

  19. 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.

  20. Cosmic Ray Confinement and Transport Models for Probing their Putative Sources

    E-Print Network [OSTI]

    Malkov, M A

    2015-01-01T23:59:59.000Z

    Recent efforts in cosmic ray (CR) confinement and transport theory are discussed. Three problems are addressed as being crucial for understanding the present day observations and their possible telltale signs of the CR origin. The first problem concerns CR behavior right after their release from a source, such as a supernova remnant (SNR). At this phase the CRs are confined near the source by self-emitted Alfven waves. The second is the problem of diffusive propagation of CRs through the turbulent ISM. This is a seemingly straightforward and long-resolved problem, but it remains controversial and reveals paradoxes. A resolution based on the Chapman-Enskog asymptotic CR transport analysis, that also includes magnetic focusing, is suggested. The third problem is about a puzzling sharp ($\\sim10^{\\circ}$) anisotropies in the CR arrival directions that might bear on important clues of their transport between the source and observer. The overarching goal is to improve our understanding of all aspects of the CR's so...

  1. Up-Scaling Geochemical Reaction Rates for Carbon Dioxide (CO2) in Deep Saline Aquifers

    SciTech Connect (OSTI)

    Lindquist, W Brent

    2009-03-03T23:59:59.000Z

    The overall goal of the project was to bridge the gap between our knowledge of small-scale geochemical reaction rates and reaction rates meaningful for modeling transport at core scales. The working hypothesis was that reaction rates, determined from laboratory measurements based upon reactions typically conducted in well mixed batch reactors using pulverized reactive media may be significantly changed in in situ porous media flow due to rock microstructure heterogeneity. Specifically we hypothesized that, generally, reactive mineral surfaces are not uniformly accessible to reactive fluids due to the random deposition of mineral grains and to the variation in flow rates within a pore network. Expected bulk reaction rates would therefore have to be correctly up-scaled to reflect such heterogeneity. The specific objective was to develop a computational tool that integrates existing measurement capabilities with pore-scale network models of fluid flow and reactive transport. The existing measurement capabilities to be integrated consisted of (a) pore space morphology, (b) rock mineralogy, and (c) geochemical reaction rates. The objective was accomplished by: (1) characterizing sedimentary sandstone rock morphology using X-ray computed microtomography, (2) mapping rock mineralogy using back-scattered electron microscopy (BSE), X-ray dispersive spectroscopy (EDX) and CMT, (3) characterizing pore-accessible reactive mineral surface area, and (4) creating network models to model acidic CO{sub 2} saturated brine injection into the sandstone rock samples.

  2. Modeling of Groundwater Flow and Radionuclide Transport at the Climax Mine sub-CAU, Nevada Test Site

    SciTech Connect (OSTI)

    K. Pohlmann; M. Ye; D. Reeves; M. Zavarin; D. Decker; J. Chapman

    2007-09-28T23:59:59.000Z

    The Yucca Flat-Climax Mine Corrective Action Unit (CAU) on the Nevada Test Site comprises 747 underground nuclear detonations, all but three of which were conducted in alluvial, volcanic, and carbonate rocks in Yucca Flat. The remaining three tests were conducted in the very different hydrogeologic setting of the Climax Mine granite stock located in Area 15 at the northern end of Yucca Flat. As part of the Corrective Action Investigation (CAI) for the Yucca Flat-Climax Mine CAU, models of groundwater flow and radionuclide transport will be developed for Yucca Flat. However, two aspects of these CAU-scale models require focused modeling at the northern end of Yucca Flat beyond the capability of these large models. First, boundary conditions and boundary flows along the northern reaches of the Yucca Flat-Climax Mine CAU require evaluation to a higher level of detail than the CAU-scale Yucca Flat model can efficiently provide. Second, radionuclide fluxes from the Climax tests require analysis of flow and transport in fractured granite, a unique hydrologic environment as compared to Yucca Flat proper. This report describes the Climax Mine sub-CAU modeling studies conducted to address these issues, with the results providing a direct feed into the CAI for the Yucca Flat-Climax Mine CAU. Three underground nuclear detonations were conducted for weapons effects testing in the Climax stock between 1962 and 1966: Hard Hat, Pile Driver, and Tiny Tot. Though there is uncertainty regarding the position of the water table in the stock, it is likely that all three tests were conducted in the unsaturated zone. In the early 1980s, the Spent Fuel Test-Climax (SFT-C) was constructed to evaluate the feasibility of retrievable, deep geologic storage of commercial nuclear reactor wastes. Detailed mapping of fractures and faults carried out for the SFT-C studies greatly expanded earlier data sets collected in association with the nuclear tests and provided invaluable information for subsequent modeling studies at Climax. The objectives of the Climax Mine sub-CAU work are to (1) provide simulated heads and groundwater flows for the northern boundaries of the Yucca Flat-Climax Mine CAU model, while incorporating alternative conceptualizations of the hydrogeologic system with their associated uncertainty, and (2) provide radionuclide fluxes from the three tests in the Climax stock using modeling techniques that account for groundwater flow in fractured granite. Meeting these two objectives required two different model scales. The northern boundary groundwater fluxes were addressed using the Death Valley Regional Flow System (DVRFS) model (Belcher, 2004) developed by the U.S. Geological Survey as a modeling framework, with refined hydrostratigraphy in a zone north of Yucca Flat and including Climax stock. Radionuclide transport was simulated using a separate model confined to the granite stock itself, but linked to regional groundwater flow through boundary conditions and calibration targets.

  3. A groundwater flow and transport model of long-term radionuclide migration in central Frenchman flat, Nevada test site

    SciTech Connect (OSTI)

    Kwicklis, Edward Michael [Los Alamos National Laboratory; Becker, Naomi M [Los Alamos National Laboratory; Ruskauff, Gregory [NAVARRO-INTERA, LLC.; De Novio, Nicole [GOLDER AND ASSOC.; Wilborn, Bill [US DOE NNSA NSO

    2010-11-10T23:59:59.000Z

    A set of groundwater flow and transport models were created for the Central Testing Area of Frenchman Flat at the former Nevada Test Site to investigate the long-term consequences of a radionuclide migration experiment that was done between 1975 and 1990. In this experiment, radionuclide migration was induced from a small nuclear test conducted below the water table by pumping a well 91 m away. After radionuclides arrived at the pumping well, the contaminated effluent was discharged to an unlined ditch leading to a playa where it was expected to evaporate. However, recent data from a well near the ditch and results from detailed models of the experiment by LLNL personnel have convincingly demonstrated that radionuclides from the ditch eventually reached the water table some 220 m below land surface. The models presented in this paper combine aspects of these detailed models with concepts of basin-scale flow to estimate the likely extent of contamination resulting from this experiment over the next 1,000 years. The models demonstrate that because regulatory limits for radionuclide concentrations are exceeded only by tritium and the half-life of tritium is relatively short (12.3 years), the maximum extent of contaminated groundwater has or will soon be reached, after which time the contaminated plume will begin to shrink because of radioactive decay. The models also show that past and future groundwater pumping from water supply wells within Frenchman Flat basin will have negligible effects on the extent of the plume.

  4. Evaluation of Anomalous Solute Transport in a Large Heterogeneous Soil Column with Mobile-Immobile Model

    E-Print Network [OSTI]

    Zhan, Hongbin

    -Immobile Model Guangyao Gao1 ; Shaoyuan Feng2 ; Hongbin Zhan3 ; Guanhua Huang4 ; and Xiaomin Mao5 Abstract

  5. Ocean Heat Transport, Sea Ice, and Multiple Climate States: Insights from Energy Balance Models

    E-Print Network [OSTI]

    Rose, Brian Edward James

    Several extensions of energy balance models (EBMs) are explored in which (i) sea ice acts to insulate the

  6. Modeling Tidal Stream Energy Extraction and its Effects on Transport Processes in a Tidal Channel and Bay System Using a Three-dimensional Coastal Ocean Model

    SciTech Connect (OSTI)

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea E.

    2013-02-28T23:59:59.000Z

    This paper presents a numerical modeling study for simulating in-stream tidal energy extraction and assessing its effects on the hydrodynamics and transport processes in a tidal channel and bay system connecting to coastal ocean. A marine and hydrokinetic (MHK) module was implemented in a three-dimensional (3-D) coastal ocean model using the momentum sink approach. The MHK model was validated with the analytical solutions for tidal channels under one-dimensional (1-D) conditions. Model simulations were further carried out to compare the momentum sink approach with the quadratic bottom friction approach. The effects of 3-D simulations on the vertical velocity profile, maximum extractable energy, and volume flux reduction across the channel were investigated through a series of numerical experiments. 3-D model results indicate that the volume flux reduction at the maximum extractable power predicted by the 1-D analytical model or two-dimensional (2-D) depth-averaged numerical model may be overestimated. Maximum extractable energy strongly depends on the turbine hub height in the water column, and which reaches a maximum when turbine hub height is located at mid-water depth. Far-field effects of tidal turbines on the flushing time of the tidal bay were also investigated. Model results demonstrate that tidal energy extraction has a greater effect on the flushing time than volume flux reduction, which could negatively affect the biogeochemical processes in estuarine and coastal waters that support primary productivity and higher forms of marine life.

  7. A Geographic Information System approach to modeling nutrient and sediment transport

    SciTech Connect (OSTI)

    Levine, D.A. [Automated Sciences Group, Inc., Oak Ridge, TN (United States); Hunsaker, C.T.; Beauchamp, J.J. [Oak Ridge National Lab., TN (United States); Timmins, S.P. [Analysas Corp., Oak Ridge, TN (United States)

    1993-02-01T23:59:59.000Z

    The objective of this study was to develop a water quality model to quantify nonpoint-source (NPS) pollution that uses a geographic information system (GIS) to link statistical modeling of nutrient and sediment delivery with the spatial arrangement of the parameters that drive the model. The model predicts annual nutrient and sediment loading and was developed, calibrated, and tested on 12 watersheds within the Lake Ray Roberts drainage basin in north Texas. Three physiographic regions are represented by these watersheds, and model success, as measured by the accuracy of load estimates, was compared within and across these regions.

  8. Upscaling of Long-Term U9VI) Desorption from Pore Scale Kinetics to Field-Scale Reactive Transport Models

    SciTech Connect (OSTI)

    Andy Miller

    2009-01-25T23:59:59.000Z

    Environmental systems exhibit a range of complexities which exist at a range of length and mass scales. Within the realm of radionuclide fate and transport, much work has been focused on understanding pore scale processes where complexity can be reduced to a simplified system. In describing larger scale behavior, the results from these simplified systems must be combined to create a theory of the whole. This process can be quite complex, and lead to models which lack transparency. The underlying assumption of this approach is that complex systems will exhibit complex behavior, requiring a complex system of equations to describe behavior. This assumption has never been tested. The goal of the experiments presented is to ask the question: Do increasingly complex systems show increasingly complex behavior? Three experimental tanks at the intermediate scale (Tank 1: 2.4m x 1.2m x 7.6cm, Tank 2: 2.4m x 0.61m x 7.6cm, Tank 3: 2.4m x 0.61m x 0.61m (LxHxW)) have been completed. These tanks were packed with various physical orientations of different particle sizes of a uranium contaminated sediment from a former uranium mill near Naturita, Colorado. Steady state water flow was induced across the tanks using constant head boundaries. Pore water was removed from within the flow domain through sampling ports/wells; effluent samples were also taken. Each sample was analyzed for a variety of analytes relating to the solubility and transport of uranium. Flow fields were characterized using inert tracers and direct measurements of pressure head. The results show that although there is a wide range of chemical variability within the flow domain of the tank, the effluent uranium behavior is simple enough to be described using a variety of conceptual models. Thus, although there is a wide range in variability caused by pore scale behaviors, these behaviors appear to be smoothed out as uranium is transported through the tank. This smoothing of uranium transport behavior transcends many of the physical and chemical heterogeneities added to the tank experiments.

  9. Hydrogen transport membranes for dehydrogenation reactions

    DOE Patents [OSTI]

    Balachandran; Uthamalingam (Hinsdale, IL)

    2008-02-12T23:59:59.000Z

    A method of converting C.sub.2 and/or higher alkanes to olefins by contacting a feedstock containing C.sub.2 and/or higher alkanes with a first surface of a metal composite membrane of a sintered homogenous mixture of an Al oxide or stabilized or partially stabilized Zr oxide ceramic powder and a metal powder of one or more of Pd, Nb, V, Zr, Ta and/or alloys or mixtures thereof. The alkanes dehydrogenate to olefins by contact with the first surface with substantially only atomic hydrogen from the dehydrogenation of the alkanes passing through the metal composite membrane. Apparatus for effecting the conversion and separation is also disclosed.

  10. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home| Visitors|Upcoming Events andWelcomeFIRST Center

  11. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 This flight2

  12. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 This flight2Research

  13. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 This

  14. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 ThisSteering Committee

  15. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 ThisSteering

  16. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2 ThisSteeringProject

  17. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2

  18. Fluid Interface Reactions, Structures and Transport

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region service area. TheEPSCI HomeTours, Programs and2FIRST Center Video Home

  19. Recent Approaches to Modeling Transport of Mercury in Surface Water and Groundwater - Case Study in Upper East Fork Poplar Creek, Oak Ridge, TN - 13349

    SciTech Connect (OSTI)

    Bostick, Kent; Daniel, Anamary [Professional Project Services, Inc., Bethel Valley Road, Oak Ridge, TN, 37922 (United States)] [Professional Project Services, Inc., Bethel Valley Road, Oak Ridge, TN, 37922 (United States); Tachiev, Georgio [Florida International University, Applied Research Center 10555 W. Flagler St., EC 2100 Miami Florida 33174 (United States)] [Florida International University, Applied Research Center 10555 W. Flagler St., EC 2100 Miami Florida 33174 (United States); Malek-Mohammadi, Siamak [Bradley University, 413A Jobst Hall, Preoria, IL 61625 (United States)] [Bradley University, 413A Jobst Hall, Preoria, IL 61625 (United States)

    2013-07-01T23:59:59.000Z

    In this case study, groundwater/surface water modeling was used to determine efficacy of stabilization in place with hydrologic isolation for remediation of mercury contaminated areas in the Upper East Fork Poplar Creek (UEFPC) Watershed in Oak Ridge, TN. The modeling simulates the potential for mercury in soil to contaminate groundwater above industrial use risk standards and to contribute to surface water contamination. The modeling approach is unique in that it couples watershed hydrology with the total mercury transport and provides a tool for analysis of changes in mercury load related to daily precipitation, evaporation, and runoff from storms. The model also allows for simulation of colloidal transport of total mercury in surface water. Previous models for the watershed only simulated average yearly conditions and dissolved concentrations that are not sufficient for predicting mercury flux under variable flow conditions that control colloidal transport of mercury in the watershed. The transport of mercury from groundwater to surface water from mercury sources identified from information in the Oak Ridge Environmental Information System was simulated using a watershed scale model calibrated to match observed daily creek flow, total suspended solids and mercury fluxes. Mercury sources at the former Building 81-10 area, where mercury was previously retorted, were modeled using a telescopic refined mesh with boundary conditions extracted from the watershed model. Modeling on a watershed scale indicated that only source excavation for soils/sediment in the vicinity of UEFPC had any effect on mercury flux in surface water. The simulations showed that colloidal transport contributed 85 percent of the total mercury flux leaving the UEFPC watershed under high flow conditions. Simulation of dissolved mercury transport from liquid elemental mercury and adsorbed sources in soil at former Building 81-10 indicated that dissolved concentrations are orders of magnitude below a target industrial groundwater concentration beneath the source and would not influence concentrations in surface water at Station 17. This analysis addressed only shallow concentrations in soil and the shallow groundwater flow path in soil and unconsolidated sediments to UEFPC. Other mercury sources may occur in bedrock and transport though bedrock to UEFPC may contribute to the mercury flux at Station 17. Generally mercury in the source areas adjacent to the stream and in sediment that is eroding can contribute to the flux of mercury in surface water. Because colloidally adsorbed mercury can be transported in surface water, actions that trap colloids and or hydrologically isolate surface water runoff from source areas would reduce the flux of mercury in surface water. Mercury in soil is highly adsorbed and transport in the groundwater system is very limited under porous media conditions. (authors)

  20. A Model of Transient Thermal Transport Phenomena Applied to the Carbonation and Calcination of a Sorbent Particle for Calcium Oxide Looping CO2 Capture

    E-Print Network [OSTI]

    looping is selected as the model cycle because of its suitability for solar-driven carbon dioxide captureA Model of Transient Thermal Transport Phenomena Applied to the Carbonation and Calcination of a Sorbent Particle for Calcium Oxide Looping CO2 Capture Lindsey Yue and Wojciech Lipi´nski, The Australian

  1. MELCOR 1.8.5 modeling aspects of fission product release, transport and deposition an assessment with recommendations.

    SciTech Connect (OSTI)

    Gauntt, Randall O.

    2010-04-01T23:59:59.000Z

    The Phebus and VERCORS data have played an important role in contemporary understanding and modeling of fission product release and transport from damaged light water reactor fuel. The data from these test programs have allowed improvement of MELCOR modeling of release and transport processes for both low enrichment uranium fuel as well as high burnup and mixed oxide (MOX) fuels. This paper discusses the synthesis of these findings in the MELCOR severe accident code. Based on recent assessments of MELCOR 1.8.5 fission product release modeling against the Phebus FPT-1 test and on observations from the ISP-46 exercise, modifications to the default MELCOR 1.8.5 release models are recommended. The assessments identified an alternative set of Booth diffusion parameters recommended by ORNL (ORNL-Booth), which produced significantly improved release predictions for cesium and other fission product groups. Some adjustments to the scaling factors in the ORNL-Booth model were made for selected fission product groups, including UO{sub 2}, Mo and Ru in order to obtain better comparisons with the FPT-1 data. The adjusted model, referred to as 'Modified ORNL-Booth,' was subsequently compared to original ORNL VI fission product release experiments and to more recently performed French VERCORS tests, and the comparisons was as favorable or better than the original CORSOR-M MELCOR default release model. These modified ORNL-Booth parameters, input to MELCOR 1.8.5 as 'sensitivity coefficients' (i.e. user input that over-rides the code defaults) are recommended for the interim period until improved release models can be implemented into MELCOR. For the case of ruthenium release in air-oxidizing conditions, some additional modifications to the Ru class vapor pressure are recommended based on estimates of the RuO{sub 2} vapor pressure over mildly hyperstoichiometric UO{sub 2}. The increased vapor pressure for this class significantly increases the net transport of Ru from the fuel to the gas stream. A formal model is needed. Deposition patterns in the Phebus FPT-1 circuit were also significantly improved by using the modified ORNL-Booth parameters, where retention of lower volatile Cs{sub 2}MoO{sub 4} is now predicted in the heated exit regions of the FPT-1 test, bringing down depositions in the FPT-1 steam generator tube to be in closer alignment with the experimental data. This improvement in 'RCS' deposition behavior preserves the overall correct release of cesium to the containment that was observed even with the default CORSOR-M model. Not correctly treated however is the release and transport of Ag to the FPT-1 containment. A model for Ag release from control rods is presently not available in MELCOR. Lack of this model is thought to be responsible for the underprediction by a factor of two of the total aerosol mass to the FPT-1 containment. It is suggested that this underprediction of airborne mass led to an underprediction of the aerosol agglomeration rate. Underprediction of the agglomeration rate leads to low predictions of the aerosol particle size in comparison to experimentally measured ones. Small particle size leads low predictions of the gravitational settling rate relative to the experimental data. This error, however, is a conservative one in that too-low settling rate would result in a larger source term to the environment. Implementation of an interim Ag release model is currently under study. In the course of this assessment, a review of MELCOR release models was performed and led to the identification of several areas for future improvements to MELCOR. These include upgrading the Booth release model to account for changes in local oxidizing/reducing conditions and including a fuel oxidation model to accommodate effects of fuel stoichiometry. Models such as implemented in the French ELSA code and described by Lewis are considered appropriate for MELCOR. A model for ruthenium release under air oxidizing conditions is also needed and should be included as part of a fuel oxidation model since fuel stoichiometry is a fundamen

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

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

    algorithm for mineral dehydration is also applied in the modeling. The Finite Element Heat and Mass transfer code (FEHM) is used to simulate coupled thermal, hydrological, and...

  3. PAT-2 (Plutonium Air-Transportable Model 2) safety analysis report

    SciTech Connect (OSTI)

    Andersen, J.A.; Davis, E.J.; Duffey, T.A.; Dupree, S.A.; George, O.L. Jr.; Ortiz, Z.

    1981-07-01T23:59:59.000Z

    The PAT-2 package is designed for the safe transport of plutonium and/or uranium in small quantities. The PAT-2 package is resistant to severe accidents, including that of a high-speed jet aircraft crash, and is designed to withstand such environments as extreme impact, crushing, puncturing and slashing loads, severe hydrocarbon-fueled fires, and deep underwater immersion, with no escape of contents. The package meets the requirements of 10 CFR 71 for Fissile Class I packages with a cargo of 15 grams of Pu-239, or other isotopic forms described herein, not to exceed 2 watts of thermal activity. This SAR presents design and oprational information including evaluations and analyses, test results, operating procedures, maintenance, and quality assurance information.

  4. NA22 Model Cities Project - LL244T An Intelligent Transportation System-Based Radiation Alert and Detection System

    SciTech Connect (OSTI)

    Peglow, S

    2004-02-24T23:59:59.000Z

    The purpose of this project was twofold: first, provide an understanding of the technical foundation and planning required for deployment of Intelligent Transportation System (ITS)-based system architectures for the protection of New York City from a terrorist attack using a vehicle-deployed nuclear device; second, work with stakeholders to develop mutual understanding of the technologies and tactics required for threat detection/identification and establish guidelines for designing operational systems and procedures. During the course of this project we interviewed and coordinated analysis with people from the New Jersey State Attorney General's office, the New Jersey State Police, the Port Authority of New York/New Jersey, the Counterterrorism Division of the New York City Police Department, the New Jersey Transit Authority, the State of New Jersey Department of Transportation, TRANSCOM and a number of contractors involved with state and federal intelligent transportation development and implementation. The basic system architecture is shown in the figure below. In an actual system deployment, radiation sensors would be co-located with existing ITS elements and the data will be sent to the Traffic Operations Center. A key element of successful system operation is the integration of vehicle data, such as license plate, EZ pass ID, vehicle type/color and radiation signature. A threat data base can also be implemented and utilized in cases where there is a suspect vehicle identified from other intelligence sources or a mobile detector system. Another key aspect of an operational architecture is the procedures used to verify the threat and plan interdiction. This was a major focus of our work and discussed later in detail. In support of the operational analysis, we developed a detailed traffic simulation model that is described extensively in the body of the report.

  5. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area

    SciTech Connect (OSTI)

    Meyer, Philip D.; Ye, Ming; Rockhold, Mark L.; Neuman, Shlomo P.; Cantrell, Kirk J.

    2007-07-30T23:59:59.000Z

    This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptual-mathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to large-scale, detailed groundwater flow and transport modeling and illustrate the benefits of the methodology I providing better estimates of predictive uncertiay8, quantitative results for use in assessing risk, and an improved understanding of the system behavior and the limitations of the models.

  6. Behavioural insights into the Modelling of Freight Transportation and Distribution Systems

    E-Print Network [OSTI]

    Bertini, Robert L.

    fuelled the extension of supply chains and the globalization of the world economy. At the micro-step modelling paradigm cannot provide adequate answers in the twenty-first century global customer-driven economy. This special issue is dedicated to innovative modelling efforts that provide new insights

  7. Macro-System Model for Hydrogen Energy Systems Analysis in Transportation: Preprint

    SciTech Connect (OSTI)

    Diakov, V.; Ruth, M.; Sa, T. J.; Goldsby, M. E.

    2012-06-01T23:59:59.000Z

    The Hydrogen Macro System Model (MSM) is a simulation tool that links existing and emerging hydrogen-related models to perform rapid, cross-cutting analysis. It allows analysis of the economics, primary energy-source requirements, and emissions of hydrogen production and delivery pathways.

  8. Up-gradient transport in a probabilistic transport model J. Gavnholt, J. Juul Rasmussen, O. E. Garcia, V. Naulin, and A. H. Nielsen

    E-Print Network [OSTI]

    fusion plasma research and it is still far from being understood. It is composed of several elements. Garcia, V. Naulin, and A. H. Nielsen Association EURATOM-Risø National Laboratory Optics and Plasma Research, OPL-128 Risø DK-4000 Roskilde, Denmark (Dated: June 24, 2005) Abstract The transport of particles

  9. Macroscopic corrosion front computations of sulfate attack in sewer pipes based on a micro-macro reaction-diffusion model

    E-Print Network [OSTI]

    Chalupeck, Vladimr; Kruschwitz, Jens; Muntean, Adrian

    2012-01-01T23:59:59.000Z

    We consider a two-scale reaction diffusion system able to capture the corrosion of concrete with sulfates. Our aim here is to define and compute two macroscopic corrosion indicators: typical pH drop and gypsum profiles. Mathematically, the system is coupled, endowed with micro-macro transmission conditions, and posed on two different spatially-separated scales: one microscopic (pore scale) and one macroscopic (sewer pipe scale). We use a logarithmic expression to compute values of pH from the volume averaged concentration of sulfuric acid which is obtained by resolving numerically the two-scale system (microscopic equations with direct feedback with the macroscopic diffusion of one of the reactants). Furthermore, we also evaluate the content of the main sulfatation reaction (corrosion) product---the gypsum---and point out numerically a persistent kink in gypsum's concentration profile. Finally, we illustrate numerically the position of the free boundary separating corroded from not-yet-corroded regions.

  10. Numerical modeling and experimental measurements of water spray impact and transport over a cylinder.

    SciTech Connect (OSTI)

    Avedisian, C. T. (Cornell University, Ithaca, NY); Presser, Cary (National Institute of Standard & Technology, Gaithersburg, MD); DesJardin, Paul Edward (University at Buffalo, New York, NY); Hewson, John C.; Yoon, Sam Sukgoo

    2005-03-01T23:59:59.000Z

    This study compares experimental measurements and numerical simulations of liquid droplets over heated (to a near surface temperature of 423 K) and unheated cylinders. The numerical model is based on an unsteady Reynolds-averaged Navier-Stokes (RANS) formulation using a stochastic separated flow (SSF) approach for the droplets that includes submodels for droplet dispersion, heat and mass transfer, and impact on a solid surface. The details of the droplet impact model are presented and the model is used to simulate water spray impingement on a cylinder. Computational results are compared with experimental measurements using phase Doppler interferometry (PDI).

  11. 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. , Fernndez, A.M. ,A.M. Fernndez and L. Montenegro, 2008b, Inverse modeling of

  12. MODELING THE FATE AND TRANSPORT OF ATRAZINE IN THE UPPER CHESAPEAKE BAY

    E-Print Network [OSTI]

    Frei, Allan

    , with species susceptible to atrazine being replaced by more resistant ones, and Solomon et al. (1996) showed analysis and a comprehensive modeling methodology used to investigate the behavior and distribution

  13. Applying Engineering and Fleet Detail to Represent Passenger Vehicle Transport in a Computable General Equilibrium Model

    E-Print Network [OSTI]

    Karplus, V.J.

    A well-known challenge in computable general equilibrium (CGE) models is to maintain correspondence between the forecasted economic and physical quantities over time. Maintaining such a correspondence is necessary to ...

  14. Computational Nanophotonics: modeling optical interactions and transport in tailored nanosystem architectures

    SciTech Connect (OSTI)

    Schatz, George; Ratner, Mark

    2014-02-27T23:59:59.000Z

    This report describes research by George Schatz and Mark Ratner that was done over the period 10/03-5/09 at Northwestern University. This research project was part of a larger research project with the same title led by Stephen Gray at Argonne. A significant amount of our work involved collaborations with Gray, and there were many joint publications as summarized later. In addition, a lot of this work involved collaborations with experimental groups at Northwestern, Argonne, and elsewhere. The research was primarily concerned with developing theory and computational methods that can be used to describe the interaction of light with noble metal nanoparticles (especially silver) that are capable of plasmon excitation. Classical electrodynamics provides a powerful approach for performing these studies, so much of this research project involved the development of methods for solving Maxwells equations, including both linear and nonlinear effects, and examining a wide range of nanostructures, including particles, particle arrays, metal films, films with holes, and combinations of metal nanostructures with polymers and other dielectrics. In addition, our work broke new ground in the development of quantum mechanical methods to describe plasmonic effects based on the use of time dependent density functional theory, and we developed new theory concerned with the coupling of plasmons to electrical transport in molecular wire structures. Applications of our technology were aimed at the development of plasmonic devices as components of optoelectronic circuits, plasmons for spectroscopy applications, and plasmons for energy-related applications.

  15. Energy Dependence of Directed Flow in Au+Au Collisions from a Multi-phase Transport Model

    E-Print Network [OSTI]

    J. Y. Chen; J. X. Zuo; X. Z. Cai; F. Liu; Y. G. Ma; A. H. Tang

    2009-12-09T23:59:59.000Z

    The directed flow of charged hadron and identified particles has been studied in the framework of a multi-phase transport (AMPT) model, for $^{197}$Au+$^{197}$Au collisions at $\\sqrt{s_{NN}}=$200, 130, 62.4, 39, 17.2 and 9.2 GeV. The rapidity, centrality and energy dependence of directed flow for charged particles over a wide rapidity range are presented. AMPT model gives the correct $v_1(y)$ slope, as well as its trend as a function of energy, while it underestimates the magnitude. Within the AMPT model, the proton $v_1$ slope is found to change its sign when the energy increases to 130 GeV - a feature that is consistent with ``anti-flow''. Hadronic re-scattering is found having little effect on $v_1$ at top RHIC energies. These studies can help us to understand the collective dynamics at early times in relativistic heavy-ion collisions, and they can also be served as references for the RHIC Beam Energy Scan program.

  16. Development of an Ontology to Assist the Modeling of Accident Scenarii "Application on Railroad Transport "

    E-Print Network [OSTI]

    Maalel, Ahmed; Mejri, Lassad; Ghezela, Henda Hajjami Ben

    2012-01-01T23:59:59.000Z

    In a world where communication and information sharing are at the heart of our business, the terminology needs are most pressing. It has become imperative to identify the terms used and defined in a consensual and coherent way while preserving linguistic diversity. To streamline and strengthen the process of acquisition, representation and exploitation of scenarii of train accidents, it is necessary to harmonize and standardize the terminology used by players in the security field. The research aims to significantly improve analytical activities and operations of the various safety studies, by tracking the error in system, hardware, software and human. This paper presents the contribution of ontology to modeling scenarii for rail accidents through a knowledge model based on a generic ontology and domain ontology. After a detailed presentation of the state of the art material, this article presents the first results of the developed model.

  17. A faster numerical scheme for a coupled system to model soil erosion and suspended sediment transport

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    or the kinetic energy of raindrop exceeds the cohesive strength of the soil particles. Once detachedA faster numerical scheme for a coupled system to model soil erosion and suspended sediment´eans, France Abstract Overland flow and soil erosion play an essential role in water quality and soil

  18. An improved numerical scheme for a coupled system to model soil erosion and polydispersed sediments transport

    E-Print Network [OSTI]

    Boyer, Edmond

    An improved numerical scheme for a coupled system to model soil erosion and polydispersed sediments, the positivity of both water depth and sediment concentrations. Recently, a well-balanced MUSCL-Hancock scheme step is required to ensure the positivity of sediment concentrations. The main result of this paper

  19. Electrochimica Acta 52 (2007) 61256140 A two-dimensional, two-phase mass transport model

    E-Print Network [OSTI]

    Zhao, Tianshou

    in the unsaturated porous medium flow theory. The two-phase flow behavior in the anode flow channel is modeled by integrating those in the different regions is solved numerically using a home-written computer code because of its high efficiency, high energy density, low emission and simple structure [1]. However

  20. Chemical characterization of ozone formation in the Houston-Galveston area: A chemical transport model study

    E-Print Network [OSTI]

    : Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution--urban and regional (0305 of the atmosphere and hence the lifetime of reactive atmospheric pollutants and many re- duced chemical species. O3 model study Wenfang Lei1 and Renyi Zhang Department of Atmospheric Sciences, Texas A&M University

  1. Reactions of NO2 with BaO/Pt(111) Model Catalysts: The Effects of BaO Film

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

    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:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared at 278, 298, andEpidermal GrowthReaction-DrivenAerosols:Thickness

  2. Optical-Model Parameters for the C-12(li-7,li-7)c-12 Reaction at 63 and 78.7 Mev

    E-Print Network [OSTI]

    Zeller, A. F.; Lui, YW; Tribble, Robert E.; Tanner, D. M.

    1980-01-01T23:59:59.000Z

    PHYSICAL REVIE% C VOLUME 22, NUMBER 4 OCTOBER 1980 Optical model parameters for the "C('Li,'Li)"C reaction at 63 and 78.7 MeV A. F. Zeller, *Y. -W. Lui, R. E. Tribble, and D. M. Tanner Cyclot'ron Institute, Texas Ac%M University, College Station... extracted from I i inelastic scattering. 1538 ZELLER, LUI, TRIBBLE, AND TANNER 22 IV. CONCLUSION The present analysis of the 'Li scattering on "C shows that a single potential set does not ap- pear to describe the data in the energy range from 48 to 78...

  3. On the modeling and simulation of of reaction-transfer dynamics in semiconductor-electrolyte solar cells

    E-Print Network [OSTI]

    -performance semiconductor-liquid junction solar cells. We propose in this work a macroscopic mathematical model, a sys- tem-liquid junction, solar cell simulation, naso-scale device modeling. 1 Introduction The mathematical modeling by the increasing need of simulation tools for designing efficient solar cells to harvest sunlight for clean energy

  4. 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

    finite-element method to model a case of chromium contamination with some success. Bobcrtson, '1974~ used au iterative, alternating- direction. inrplicit finite-difference scheme to solve the groundwater flow equation and a. nrodified method... the location of the INEL and generalized groundwater flow lines of the Snake River Plain aquifer [from Barraclough et al. , 1981). . 12 3. Map showing the major facilities and surface water features at the INEL [from Robertson et al. , 1974]. 4. Volcanic...

  5. A regional economic impact model for identifying the relationship between transportation investments and economic development

    E-Print Network [OSTI]

    Freyre, German Eleodoro

    1989-01-01T23:59:59.000Z

    OF CONTENTS Chapter Page I INTRODUCIION 1. 1 General Background 1. 2 Objectives of the Research 1. 3 Summary of Research Plan 1. 4 Thesis Organization II LITERATURE REVIEW I I I OVERVIEW OF THE REIMHS MODEL 14 3. 1 Distribution of the Monetary... Investment Among the Relevant Highway Industries 14 3. 2 Estimation of Monetary Benefits Associated with Efficiency, Mobility, and Safety Improvements I 6 3. 3 Development of Matrix of Integrated Results 21 3. 4 Multiplier Matrices and the Resulting...

  6. Transportation Networks and Location A Geometric Approach

    E-Print Network [OSTI]

    Palop del Río, Belén

    Transportation Networks and Location A Geometric Approach Belén Palop1,2 1Departamento de March 2009 Florida State University #12;Belén Palop, UVa, SUNY Outline Transportation Network Model;Transportation Network Model Belén Palop, UVa, SUNY Outline Transportation Network Model Network placement

  7. A CFD-based wind solver for a fast response transport and dispersion model

    SciTech Connect (OSTI)

    Gowardhan, Akshay A [Los Alamos National Laboratory; Brown, Michael J [Los Alamos National Laboratory; Pardyjak, Eric R [UNIV OF UTAH; Senocak, Inanc [BOISE STATE UNIV

    2010-01-01T23:59:59.000Z

    In many cities, ambient air quality is deteriorating leading to concerns about the health of city inhabitants. In urban areas with narrow streets surrounded by clusters of tall buildings, called street canyons, air pollution from traffic emissions and other sources is difficult to disperse and may accumulate resulting in high pollutant concentrations. For various situations, including the evacuation of populated areas in the event of an accidental or deliberate release of chemical, biological and radiological agents, it is important that models should be developed that produce urban flow fields quickly. For these reasons it has become important to predict the flow field in urban street canyons. Various computational techniques have been used to calculate these flow fields, but these techniques are often computationally intensive. Most fast response models currently in use are at a disadvantage in these cases as they are unable to correlate highly heterogeneous urban structures with the diagnostic parameterizations on which they are based. In this paper, a fast and reasonably accurate computational fluid dynamics (CFD) technique that solves the Navier-Stokes equations for complex urban areas has been developed called QUIC-CFD (Q-CFD). This technique represents an intermediate balance between fast (on the order of minutes for a several block problem) and reasonably accurate solutions. The paper details the solution procedure and validates this model for various simple and complex urban geometries.

  8. Rain water transport and storage in a model sandy soil with hydrogel particle additives

    E-Print Network [OSTI]

    Y. Wei; D. J. Durian

    2014-02-10T23:59:59.000Z

    We study rain water infiltration and drainage in a dry model sandy soil with superabsorbent hydrogel particle additives by measuring the mass of retained water for non-ponding rainfall using a self-built 3D laboratory set-up. In the pure model sandy soil, the retained water curve measurements indicate that instead of a stable horizontal wetting front that grows downward uniformly, a narrow fingered flow forms under the top layer of water-saturated soil. This rain water channelization phenomenon not only further reduces the available rain water in the plant root zone, but also affects the efficiency of soil additives, such as superabsorbent hydrogel particles. Our studies show that the shape of the retained water curve for a soil packing with hydrogel particle additives strongly depends on the location and the concentration of the hydrogel particles in the model sandy soil. By carefully choosing the particle size and distribution methods, we may use the swollen hydrogel particles to modify the soil pore structure, to clog or extend the water channels in sandy soils, or to build water reservoirs in the plant root zone.

  9. Aerosol particle transport modeling for preclosure safety studies of nuclear waste repositories

    SciTech Connect (OSTI)

    Gelbard, F. [Sandia National Labs., Albuquerque, NM (USA)

    1989-01-01T23:59:59.000Z

    An important concern for preclosure safety analysis of a nuclear waste repository is the potential release to the environment of respirable aerosol particles. Such particles, less than 10 {mu}m in aerodynamic diameter, may have significant adverse health effects if inhaled. To assess the potential health effects of these particles, it is not sufficient to determine the mass fraction of respirable aerosol. The chemical composition of the particles is also of importance since different radionuclides may pose vastly different health hazards. Thus, models are needed to determine under normal and accident conditions the particle size and the chemical composition distributions of aerosol particles as a function of time and of position in the repository. In this work a multicomponent sectional aerosol model is used to determine the aerosol particle size and composition distributions in the repository. A range of aerosol mass releases with varying mean particle sizes and chemical compositions is used to demonstrate the sensitivities and uncertainties of the model. Decontamination factors for some locations in the repository are presented. 8 refs., 1 tab.

  10. Transportation Services

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

    Transportation Services Transporting nuclear materials within the United States and throughout the world is a complicated and sometimes highly controversial effort requiring...

  11. Local Transportation

    E-Print Network [OSTI]

    Local Transportation. Transportation from the Airport to Hotel. There are two types of taxi companies that operate at the airport: special and regular taxis (

  12. Greening Transportation

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

    Transportation Goal 2: Greening Transportation LANL supports and encourages employees to reduce their personal greenhouse gas emissions by offering various commuting and work...

  13. WaterTransport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization

    SciTech Connect (OSTI)

    J. Vernon Cole; Abhra Roy; Ashok Damle; Hari Dahr; Sanjiv Kumar; Kunal Jain; Ned Djilai

    2012-10-02T23:59:59.000Z

    Water management in Proton Exchange Membrane, PEM, Fuel Cells is challenging because of the inherent conflicts between the requirements for efficient low and high power operation. Particularly at low powers, adequate water must be supplied to sufficiently humidify the membrane or protons will not move through it adequately and resistance losses will decrease the cell efficiency. At high power density operation, more water is produced at the cathode than is necessary for membrane hydration. This excess water must be removed effectively or it will accumulate in the Gas Diffusion Layers, GDLs, between the gas channels and catalysts, blocking diffusion paths for reactants to reach the catalysts and potentially flooding the electrode. As power density of the cells is increased, the challenges arising from water management are expected to become more difficult to overcome simply due to the increased rate of liquid water generation relative to fuel cell volume. Thus, effectively addressing water management based issues is a key challenge in successful application of PEMFC systems. In this project, CFDRC and our partners used a combination of experimental characterization, controlled experimental studies of important processes governing how water moves through the fuel cell materials, and detailed models and simulations to improve understanding of water management in operating hydrogen PEM fuel cells. The characterization studies provided key data that is used as inputs to all state-of-the-art models for commercially important GDL materials. Experimental studies and microscopic scale models of how water moves through the GDLs showed that the water follows preferential paths, not branching like a river, as it moves toward the surface of the material. Experimental studies and detailed models of water and airflow in fuel cells channels demonstrated that such models can be used as an effective design tool to reduce operating pressure drop in the channels and the associated costs and weight of blowers and pumps to force air and hydrogen gas through the fuel cell. Promising improvements to materials structure and surface treatments that can potentially aid in managing the distribution and removal of liquid water were developed; and improved steady-state and freeze-thaw performance was demonstrated for a fuel cell stack under the self-humidified operating conditions that are promising for stationary power generation with reduced operating costs.

  14. Ground-water flow and transport modeling of the NRC-licensed waste disposal facility, West Valley, New York

    SciTech Connect (OSTI)

    Kool, J.B.; Wu, Y.S. (HydroGeoLogic, Inc., Herndon, VA (United States))

    1991-10-01T23:59:59.000Z

    This report describes a simulation study of groundwater flow and radionuclide transport from disposal at the NRC licensed waste disposal facility in West Valley, New York. A transient, precipitation driven, flow model of the near-surface fractured till layer and underlying unweathered till was developed and calibrated against observed inflow data into a recently constructed interceptor trench for the period March--May 1990. The results suggest that lateral flow through the upper, fractured till layer may be more significant than indicated by previous, steady state flow modeling studies. A conclusive assessment of the actual magnitude of lateral flow through the fractured till could however not be made. A primary factor contributing to this uncertainty is the unknown contribution of vertical infiltration through the interceptor trench cap to the total trench inflow. The second part of the investigation involved simulation of the migration of Sr-90, Cs-137 and Pu-239 from the one of the fuel hull disposal pits. A first-order radionuclide leach rate with rate coefficient of 10{sup {minus}6}/day was assumed to describe radionuclide release into the disposal pit. The simulations indicated that for wastes buried below the fractured till zone, no significant migration would occur. However, under the assumed conditions, significant lateral migration could occur for radionuclides present in the upper, fractured till zone. 23 refs., 68 figs., 12 tabs.

  15. Chamber transport

    SciTech Connect (OSTI)

    OLSON,CRAIG L.

    2000-05-17T23:59:59.000Z

    Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

  16. Chemical Reactions in DSMC

    SciTech Connect (OSTI)

    Bird, G. A. [GAB Consulting Pty Ltd, 144/110 Sussex Street, Sydney NSW 2000 (Australia)

    2011-05-20T23:59:59.000Z

    DSMC simulations of chemically reacting gas flows have generally employed procedures that convert the macroscopic chemical rate equations to reaction cross-sections at the microscopic level. They therefore depend on the availability of experimental data that has been fitted to equations of the Arrhenius form. This paper presents a physical model for dissociation and recombination reactions and a phenomenological model for exchange and chain reactions. These are based on the vibrational states of the colliding molecules and do not require any experimentally-based data. The simplicity of the models allows the corresponding rate equations to be written down and, while these are not required for the implementation of the models, they facilitate their validation. The model is applied to a typical hypersonic atmospheric entry problem and the results are compared with the corresponding results from the traditional method. It is also used to investigate both spontaneous and forced ignition as well as the structure of a deflagration wave in an oxygen-hydrogen mixture.

  17. Analysis of the NAEG model of transuranic radionuclide transport and dose

    SciTech Connect (OSTI)

    Kercher, J.R.; Anspaugh, L.R.

    1984-11-01T23:59:59.000Z

    We analyze the model for estimating the dose from /sup 239/Pu developed for the Nevada Applied Ecology Group (NAEG) by using sensitivity analysis and uncertainty analysis. Sensitivity analysis results suggest that the air pathway is the critical pathway for the organs receiving the highest dose. Soil concentration and the factors controlling air concentration are the most important parameters. The only organ whose dose is sensitive to parameters in the ingestion pathway is the GI tract. The air pathway accounts for 100% of the dose to lung, upper respiratory tract, and thoracic lymph nodes; and 95% of its dose via ingestion. Leafy vegetable ingestion accounts for 70% of the dose from the ingestion pathway regardless of organ, peeled vegetables 20%; accidental soil ingestion 5%; ingestion of beef liver 4%; beef muscle 1%. Only a handful of model parameters control the dose for any one organ. The number of important parameters is usually less than 10. Uncertainty analysis indicates that choosing a uniform distribution for the input parameters produces a lognormal distribution of the dose. The ratio of the square root of the variance to the mean is three times greater for the doses than it is for the individual parameters. As found by the sensitivity analysis, the uncertainty analysis suggests that only a few parameters control the dose for each organ. All organs have similar distributions and variance to mean ratios except for the lymph modes. 16 references, 9 figures, 13 tables.

  18. Bayesian data assimilation for stochastic multiscale models of transport in porous media.

    SciTech Connect (OSTI)

    Marzouk, Youssef M. (Massachusetts Institute of Technology, Cambridge, MA); van Bloemen Waanders, Bart Gustaaf (Sandia National Laboratories, Albuquerque NM); Parno, Matthew (Massachusetts Institute of Technology, Cambridge, MA); Ray, Jaideep; Lefantzi, Sophia; Salazar, Luke (Sandia National Laboratories, Albuquerque NM); McKenna, Sean Andrew (Sandia National Laboratories, Albuquerque NM); Klise, Katherine A. (Sandia National Laboratories, Albuquerque NM)

    2011-10-01T23:59:59.000Z

    We investigate Bayesian techniques that can be used to reconstruct field variables from partial observations. In particular, we target fields that exhibit spatial structures with a large spectrum of lengthscales. Contemporary methods typically describe the field on a grid and estimate structures which can be resolved by it. In contrast, we address the reconstruction of grid-resolved structures as well as estimation of statistical summaries of subgrid structures, which are smaller than the grid resolution. We perform this in two different ways (a) via a physical (phenomenological), parameterized subgrid model that summarizes the impact of the unresolved scales at the coarse level and (b) via multiscale finite elements, where specially designed prolongation and restriction operators establish the interscale link between the same problem defined on a coarse and fine mesh. The estimation problem is posed as a Bayesian inverse problem. Dimensionality reduction is performed by projecting the field to be inferred on a suitable orthogonal basis set, viz. the Karhunen-Loeve expansion of a multiGaussian. We first demonstrate our techniques on the reconstruction of a binary medium consisting of a matrix with embedded inclusions, which are too small to be grid-resolved. The reconstruction is performed using an adaptive Markov chain Monte Carlo method. We find that the posterior distributions of the inferred parameters are approximately Gaussian. We exploit this finding to reconstruct a permeability field with long, but narrow embedded fractures (which are too fine to be grid-resolved) using scalable ensemble Kalman filters; this also allows us to address larger grids. Ensemble Kalman filtering is then used to estimate the values of hydraulic conductivity and specific yield in a model of the High Plains Aquifer in Kansas. Strong conditioning of the spatial structure of the parameters and the non-linear aspects of the water table aquifer create difficulty for the ensemble Kalman filter. We conclude with a demonstration of the use of multiscale stochastic finite elements to reconstruct permeability fields. This method, though computationally intensive, is general and can be used for multiscale inference in cases where a subgrid model cannot be constructed.

  19. Modeling Gas Transport in the Shallow Subsurface During the ZERT CO2 Release Test

    SciTech Connect (OSTI)

    Oldenburg, Curtis M.; Lewicki, Jennifer L.; Dobeck, Laura; Spangler, Lee

    2009-01-15T23:59:59.000Z

    We used the multiphase and multicomponent TOUGH2/EOS7CA model to carry out predictive simulations of CO{sub 2} injection into the shallow subsurface of an agricultural field in Bozeman, Montana. The purpose of the simulations was to inform the choice of CO{sub 2} injection rate and design of monitoring and detection activities for a CO{sub 2} release experiment. The release experiment configuration consists of a long horizontal well (70 m) installed at a depth of approximately 2.5 m into which CO{sub 2} is injected to mimic leakage from a geologic carbon sequestration site through a linear feature such as a fault. We estimated the permeability of the soil and cobble layers present at the site by manual inversion of measurements of soil CO{sub 2} flux from a vertical-well CO{sub 2} release. Based on these estimated permeability values, predictive simulations for the horizontal well showed that CO{sub 2} injection just below the water table creates an effective gas-flow pathway through the saturated zone up to the unsaturated zone. Once in the unsaturated zone, CO{sub 2} spreads out laterally within the cobble layer, where liquid saturation is relatively low. CO{sub 2} also migrates upward into the soil layer through the capillary barrier and seeps out at the ground surface. The simulations predicted a breakthrough time of approximately two days for the 100kg d{sup -1} injection rate, which also produced a flux within the range desired for testing detection and monitoring approaches. The seepage area produced by the model was approximately five meters wide above the horizontal well, compatible with the detection and monitoring methods tested. For a given flow rate, gas-phase diffusion of CO{sub 2} tends to dominate over advection near the ground surface, where the CO{sub 2} concentration gradient is large, while advection dominates deeper in the system.

  20. Development and use of the GREET model to estimate fuel-cycle energy use and emissions of various transportation technologies and fuels

    SciTech Connect (OSTI)

    Wang, M.Q.

    1996-03-01T23:59:59.000Z

    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, carbon monoxide, nitrogen oxides, sulfur oxides, 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 (hydrogen, 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.