National Library of Energy BETA

Sample records for reaction transport model

  1. 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

  2. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    SciTech Connect (OSTI)

    Wampler, William R.; Myers, Samuel M.

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  3. Formation of hypernuclei in high energy reactions within a covariant transport model

    E-Print Network [OSTI]

    T. Gaitanos; H. Lenske; U. Mosel

    2009-04-14

    We investigate the formation of fragments with strangeness degrees of freedom in proton- and heavy-ion-induced reactions at high relativistic energies. The model used is a combination of a dynamical transport model and a statistical approach of fragment formation. We discuss in detail the applicability and limitations of such a hybrid model by comparing data on spectator fragmentation at relativistic $SIS/GSI$-energies. The theoretical results are analyzed in terms of spectator fragmentation with strangeness degrees of freedom such as the production of single-$\\Lambda-{}^{3,4,5}He$ hypernuclei. We provide theoretical estimates on the spectra and on inclusive cross sections of light hypernuclei, which could be helpful for future experiments on hypernuclear physics at the new GSI- and J-PARC-facilities.

  4. 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.

    2000-01-01

    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.

  5. 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

    2008-08-05

    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.

  6. 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.

    2013-03-01

    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.

  7. Transport-theoretical Description of Nuclear Reactions

    E-Print Network [OSTI]

    O. Buss; T. Gaitanos; K. Gallmeister; H. van Hees; M. Kaskulov; O. Lalakulich; A. B. Larionov; T. Leitner; J. Weil; U. Mosel

    2012-02-02

    In this review we first outline the basics of transport theory and its recent generalization to off-shell transport. We then present in some detail the main ingredients of any transport method using in particular the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of this theory as an example. We discuss the potentials used, the ground state initialization and the collision term, including the in-medium modifications of the latter. The central part of this review covers applications of GiBUU to a wide class of reactions, starting from pion-induced reactions over proton and antiproton reactions on nuclei to heavy-ion collisions (up to about 30 AGeV). A major part concerns also the description of photon-, electron- and neutrino-induced reactions (in the energy range from a few 100 MeV to a few 100 GeV). For this wide class of reactions GiBUU gives an excellent description with the same physics input and the same code being used. We argue that GiBUU is an indispensable tool for any investigation of nuclear reactions in which final-state interactions play a role. Studies of pion-nucleus interactions, nuclear fragmentation, heavy ion reactions, hyper nucleus formation, hadronization, color transparency, electron-nucleus collisions and neutrino-nucleus interactions are all possible applications of GiBUU and are discussed in this article.

  8. Propagation in a kinetic reaction-transport equation: travelling waves and accelerating fronts

    E-Print Network [OSTI]

    Calvez, Vincent

    describes particles moving according to a velocity-jump process, and proliferating thanks to a reaction termPropagation in a kinetic reaction-transport equation: travelling waves and accelerating fronts the existence and stability of travelling wave solutions of a kinetic reaction- transport equation. The model

  9. Front propagation in a kinetic reaction-transport equation Emeric Bouin

    E-Print Network [OSTI]

    Boyer, Edmond

    according to a velocity-jump process, and proliferating thanks to a reaction term of monostable typeFront propagation in a kinetic reaction-transport equation Emeric Bouin , Vincent Calvez wave solutions of a kinetic reaction- transport equation. The model describes particles moving

  10. UZ Colloid Transport Model

    SciTech Connect (OSTI)

    M. McGraw

    2000-04-13

    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. Economic Model Predictive Control: Handling Preventive Actuator and Sensor Maintenance and Application to Transport-Reaction Processes

    E-Print Network [OSTI]

    Lao, Liangfeng

    2015-01-01

    for CFD on the simulation of biogas combustion in bluff-bodydevelop its CFD model considering both the combustion in thedevelop its CFD model considering both the combustion in the

  12. Reaction-Based Transport Modeling of Iron Reduction and Uranium Immobilization at Area 2 of the NABIR Field Research Center

    SciTech Connect (OSTI)

    Yeh, Gour-Tsyh

    2006-06-01

    This research project (started Fall 2004) was funded by a grant to The Pennsylvania State University, University of Central Florida, and The University of Alabama in the Integrative Studies Element of the NABIR Program (DE-FG04-ER63914/63915/63196). Dr. Eric Roden, formerly at The University of Alabama, is now at the University of Wisconsin - Madison. Our project focuses on the development of a mechanistic understanding and quantitative models of coupled Fe(III)/U(VI) reduction in FRC Area 2 sediments. This work builds on our previous studies of microbial Fe(III) and U(VI) reduction, and is directly aligned with the Scheibe et al. NABIR FRC Field Project at Area 2.

  13. 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

  14. Uranium Transport Modeling

    SciTech Connect (OSTI)

    Bostick, William D.

    2008-01-15

    Uranium contamination is prevalent at many of the U.S. DOE facilities and at several civilian sites that have supported the nuclear fuel cycle. The potential off-site mobility of uranium depends on the partitioning of uranium between aqueous and solid (soil and sediment) phases. Hexavalent U (as uranyl, UO{sub 2}{sup 2+}) is relatively mobile, forming strong complexes with ubiquitous carbonate ion which renders it appreciably soluble even under mild reducing conditions. In the presence of carbonate, partition of uranyl to ferri-hydrate and select other mineral phases is usually maximum in the near-neutral pH range {approx} 5-8. The surface complexation reaction of uranyl with iron-containing minerals has been used as one means to model subsurface migration, used in conjunction with information on the site water chemistry and hydrology. Partitioning of uranium is often studied by short-term batch 'equilibrium' or long-term soil column testing ; MCLinc has performed both of these methodologies, with selection of method depending upon the requirements of the client or regulatory authority. Speciation of uranium in soil may be determined directly by instrumental techniques (e.g., x-ray photoelectron spectroscopy, XPS; x-ray diffraction, XRD; etc.) or by inference drawn from operational estimates. Often, the technique of choice for evaluating low-level radionuclide partitioning in soils and sediments is the sequential extraction approach. This methodology applies operationally-defined chemical treatments to selectively dissolve specific classes of macro-scale soil or sediment components. These methods recognize that total soil metal inventory is of limited use in understanding bioavailability or metal mobility, and that it is useful to estimate the amount of metal present in different solid-phase forms. Despite some drawbacks, the sequential extraction method can provide a valuable tool to distinguish among trace element fractions of different solubility related to mineral phases. Four case studies are presented: Water and Soil Characterization, Subsurface Stabilization of Uranium and other Toxic Metals, Reductive Precipitation (in situ bioremediation) of Uranium, and Physical Transport of Particle-bound Uranium by Erosion.

  15. Fluid Interface Reactions, Structures and Transport

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

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaonforsupernovae model (Journal About DOE ButtonFSO Homefeature CS

  16. Improved Geothermometry Through Multivariate Reaction Path Modeling...

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

    Improved Geothermometry Through Multivariate Reaction Path Modeling and Evaluation of Geomicrobiological Influences on Geochemical Temperature Indicators Improved Geothermometry...

  17. Transport Properties for Combustion Modeling

    E-Print Network [OSTI]

    Brown, N.J.

    2010-01-01

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

  18. 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.

  19. Spallation reactions. A successful interplay between modeling and applications

    E-Print Network [OSTI]

    J. -C. David

    2015-05-13

    The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200 MeV deuterons and 400 MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. The same year R. Serber describes the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a worskhop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improvements achieved since Serber. Particle transport codes can then rely on such spallation models to treat the reactions between a light particle and an atomic nucleus with energies spanning from few tens of MeV up to some GeV. An overview of the spallation reactions modeling is presented in order to point out the incomparable contribution of models based on basic physics to numerous applications where such reactions occur. Validations or benchmarks, which are necessary steps in the improvement process, are also addressed, as well as the potential future domains of development. Spallation reactions modeling is a representative case of continuous studies aiming at understanding a reaction mechanism and which end up in a powerful tool.

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

    E-Print Network [OSTI]

    Clement, Prabhakar

    nuclear waste sites contaminated with radioactive species and their daughter products and hazardous wasteGeneralized solution to multispecies transport equations coupled with a first-order reaction for deriving analytical solutions to multispecies transport equations coupled with multiparent, serial

  1. Solar Models and NACRE thermonuclear reaction rates

    E-Print Network [OSTI]

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

    1999-07-27

    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.

  2. COMBINED MODELING OF ACCELERATION, TRANSPORT, AND HYDRODYNAMIC...

    Office of Scientific and Technical Information (OSTI)

    COMBINED MODELING OF ACCELERATION, TRANSPORT, AND HYDRODYNAMIC RESPONSE IN SOLAR FLARES. I. THE NUMERICAL MODEL Citation Details In-Document Search Title: COMBINED MODELING OF...

  3. Pore Models Track Reactions in Underground Carbon Capture

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

    Pore Models Track Reactions in Underground Carbon Capture Pore Models Track Reactions in Underground Carbon Capture September 25, 2014 | Tags: Advanced Scientific Computing...

  4. Effect of Transport and Reaction on the Shape Evolutionof Cavities during Wet Chemical Etching

    E-Print Network [OSTI]

    Economou, Demetre J.

    Effect of Transport and Reaction on the Shape Evolutionof Cavities during Wet Chemical Etching Chee Burm Shin and Demetre J. Economou* Department of Chemical Engineering, University of Houston, Houston, Texas 77204-4792 ABSTRACT The effect of fluid flow, transport, and reaction on the shape evolution

  5. Analysis of RADTRAN transportation model

    SciTech Connect (OSTI)

    Resnikoff, M. [Radioactive Waste Management Associates, New York, NY (United States)

    1990-10-01

    This paper reviews the RADTRAN computer model, used to estimate the risks of transporting waste to a high-level repository. Ignoring high consequence accidents, human error, sabotage, realistic accident scenarios and recent health effects data leads to an underestimate of potential health effects. Potential economic costs following an accident in a rural area are low compared to a scale-up of the Palomares, Spain clean-up and other estimates. The author states that these costs can vary widely depending on the accident locale and whether certain direct and indirect costs are included.

  6. Transportation Network Modeling in Passenger Transportation

    E-Print Network [OSTI]

    Daniels, Thomas E.

    , Cars (hybrid and gasoline) Trains (electric and diesel) Barges Planes Decision Variables - Modeled (infrastructure not taken into account) VDxxGasoline car Hybrid car GD M$/M gallon M gallon Infrastructure Demand Decision Variables Status - Personal vehicles Cars/ Gasoline & electricity Highway

  7. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    & pipelines Coal mines & rail/barges Storage Electricity market Electric gen & trans Costs ... ... Primary Energy Supplies Gas Coal Railroad, Barge ... ... Storage & Transportation Systems Energy Transportation Networks #12;Structural Model: Energy Flows GAS COAL ELECTRIC Case A: 2002

  8. SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

    SciTech Connect (OSTI)

    B.W. ARNOLD

    2004-10-27

    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.

  9. 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

  10. Semiclassical Transport Models for Semiconductor Spintronics

    E-Print Network [OSTI]

    Saikin, Semion

    Semiclassical Transport Models for Semiconductor Spintronics Yuriy V. Pershin,1,2 Semion Saikin1 spintronic device modeling. These include drift-diffusion models, kinetic transport equations and Monte Carlo in semiconductor structures have moved the state of the art closer to the realiza- tion of novel spintronic devices

  11. Semiclassical Transport Models for Semiconductor Spintronics

    E-Print Network [OSTI]

    Privman, Vladimir

    Semiclassical Transport Models for Semiconductor Spintronics Yuriy V. Pershin,1,2 Semion Saikin1 spintronic device modeling. These include drift-diffusion models, kinetic transport equations and Monte Carlo in semiconductor structures have moved the state of the art closer to the realization of novel spintronic devices

  12. RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS

    SciTech Connect (OSTI)

    S. Magnuson

    2004-11-01

    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.

  13. Uphill transport and the probabilistic transport model B. Ph. van Milligen

    E-Print Network [OSTI]

    van Milligen, Boudewijn

    Uphill transport and the probabilistic transport model B. Ph. van Milligen Asociacion EURATOM-CIEMAT

  14. A GENERAL EMPIRICALLY BASED MICROINSTABILITY TRANSPORT MODEL

    E-Print Network [OSTI]

    Vlad, Gregorio

    by turbulent processes. At present, no definitive transport model (i.e. a closed expression for energygyro-Bohm, shear dependent thermal diffusion coefficient to model the anomalous thermal transport in tokamaks processes generated by small scale, collisionless, electro- static microinstabilities (Romanelli, F., Zonca

  15. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

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

  16. Continuous time Markov chain models for chemical reaction networks

    E-Print Network [OSTI]

    Kurtz, Tom

    Continuous time Markov chain models for chemical reaction networks David F. Anderson Departments Abstract A reaction network is a chemical system involving multiple reactions and chemical species exploit the representation of the stochastic equation for chemical reaction networks and, under what

  17. Gamma and the chemical reaction model: fteen years after?

    E-Print Network [OSTI]

    Fradet, Pascal

    Gamma and the chemical reaction model: fteen years after? Jean-Pierre Ban^atre1, Pascal Fradet2 the formalism is to describe computation as a form of chemical reaction on a collection of individual pieces on unexpected applications of the chemical reaction model, showing that this paradigm has been a source

  18. Modelling simultaneous precipitation reactions in austenitic stainless steels.

    E-Print Network [OSTI]

    Cambridge, University of

    Modelling simultaneous precipitation reactions in austenitic stainless steels. T. Sourmail and H. K developed for simultaneous precipitation reactions in austenitic stainless steels, taking into account for important phases in creep-resistant austenitic stainless steels. 1 Introduction Precipitation phenomena

  19. Decision Models for Bulk Energy Transportation

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    Decision Models for Bulk Energy Transportation Networks James D. McCalley August 23, 2005 #12, and Electric Transportation Systems (1) What energy flow patterns would yield significantly improved energy (ISU - Randy Larabee) City of Ames (Ames - Merlin Hove) MidAmerican Energy (Des Moines - Alan O

  20. Multiphase transport model for relativistic nuclear collisions

    E-Print Network [OSTI]

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

    2000-01-01

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

  1. Integration of Nontraditional Isotopic Systems Into Reaction-Transport

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURING OFFICE INDUSTRIAL TECHNICAL8-02Department ofInversions | Department ofModels of

  2. Use of Neural Networks with Advection-Diffusion-Reaction Models

    E-Print Network [OSTI]

    Hawai'i at Manoa, University of

    Use of Neural Networks with Advection-Diffusion-Reaction Models to Estimate Large-Scale Movements-350 #12;Adam, M. S., and J. R. Sibert, Use of Neural Networks with Advection-Diffusion-Reaction Models Motivation 2 2 The model 2 3 Parameterizing movement fields 4 3.1 User of neural networks 5 3.2 Scaling

  3. Current Transportation Models Used in the Vehicle Technologies Program

    SciTech Connect (OSTI)

    2009-04-06

    A summary of various transportation models (VISION, TRUCK, GREET, Oil Peaking Model, Feebate Model, Oil Security Metrics Model, ORNL PHEV Choice Model: Version 1, PSAT, PSAT-PRO,

  4. World Energy Projection System Plus Model Documentation: Transportation Model

    Reports and Publications (EIA)

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) International Transportation model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  5. Modeling uranium transport in acidic contaminated groundwater with base addition

    SciTech Connect (OSTI)

    Zhang, Fan [Institute of Tibetan Plateau Research, Chinese Academy of Sciences; Luo, Wensui [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Brooks, Scott C [ORNL; Watson, David B [ORNL; Jardine, Philip [University of Tennessee, Knoxville (UTK); Gu, Baohua [ORNL

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  6. 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)

    1999-01-01

    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.

  7. A reaction class approach for modeling gas phase reaction rates Thanh N. Truong,* Wendell T. Duncan and Max Tirtowidjojo

    E-Print Network [OSTI]

    Truong, Thanh N.

    present a series of new tunneling models based on a reaction class approach. Reaction class consists the growing number of known elementary reaction rate constants, the current kinetic data- base is far from idea of this approach is based on the following realization. Reactions in a kinetic model

  8. 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

    2013-06-01

    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.

  9. Model for assessing bronchial mucus transport

    SciTech Connect (OSTI)

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

    1984-02-01

    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.

  10. 4.0 Application of Chemical Reaction Models Computerized chemical reaction models based on thermodynamic principles may be used to calculate

    E-Print Network [OSTI]

    4.0 Application of Chemical Reaction Models Computerized chemical reaction models based. The capabilities of a chemical reaction model depend on the models incorporated into its computer code is an equilibrium chemical reaction model. It was developed with EPA funding by originally combining

  11. Decision Models for Bulk Energy Transportation Networks

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    natural gas pipeline capacity from gulf to NE? Production: How would major investment in a specific/trading restrictions? What would be impacts on fuel and electricity markets? How do high natural gas prices drive1 Decision Models for Bulk Energy Transportation Networks Electrical Engineering Professor Jim Mc

  12. CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER

    E-Print Network [OSTI]

    Boyer, Edmond

    CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER F. QUIOT1 , C.Goblet@ensmp.fr Keywords : numerical model, groundwater contamination, chlorinated solvents, natural attnuation attnuation models to predict transport and fate of chlorinated solvents in saturated groundwater Systems

  13. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect (OSTI)

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

    2009-01-20

    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.

  14. Fire and materials modeling for transportation systems

    SciTech Connect (OSTI)

    Skocypec, R.D.; Gritzo, L.A.; Moya, J.L.; Nicolette, V.F.; Tieszen, S.R.; Thomas, R.

    1994-10-01

    Fire is an important threat to the safety of transportation systems. Therefore, understanding the effects of fire (and its interaction with materials) on transportation systems is crucial to quantifying and mitigating the impact of fire on the safety of those systems. Research and development directed toward improving the fire safety of transportation systems must address a broad range of phenomena and technologies, including: crash dynamics, fuel dispersion, fire environment characterization, material characterization, and system/cargo thermal response modeling. In addition, if the goal of the work is an assessment and/or reduction of risk due to fires, probabilistic risk assessment technology is also required. The research currently underway at Sandia National Laboratories in each of these areas is summarized in this paper.

  15. Analytical mesoscale modeling of aeolian sand transport

    E-Print Network [OSTI]

    Marc Lmmel; Anne Meiwald; Klaus Kroy

    2014-05-03

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

  16. Multiplicative colored noise in linearized models of biochemical reaction networks

    E-Print Network [OSTI]

    Ingalls, Brian

    Multiplicative colored noise in linearized models of biochemical reaction networks Matthew Scott is often modeled by white noise, though results obtained in this fashion tend to overstate the effect to a model of bacterial chemotaxis with multiple explicit noise sources. The frequency response

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

    SciTech Connect (OSTI)

    Yortsos, Y.C.

    2001-05-29

    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.

  18. AEROSOLS AND CLOUDS IN CHEMICAL TRANSPORT MODELS AND CLIMATE MODELS

    E-Print Network [OSTI]

    of Earth's climate system. Clouds are highly reflective in the solar spectrum, yet strongly absorbingAEROSOLS AND CLOUDS IN CHEMICAL TRANSPORT MODELS AND CLIMATE MODELS Ulrike Lohmann1 and Stephen E Forum: Perturbed Clouds in the Climate System, Frankfurt, Germany March 2-7, 2008 Environmental Sciences

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

    E-Print Network [OSTI]

    P. A. Kravchuk; D. G. Yakovlev

    2014-01-11

    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.

  20. RADTRAD: A simplified model for RADionuclide Transport and Removal...

    Office of Scientific and Technical Information (OSTI)

    RADTRAD: A simplified model for RADionuclide Transport and Removal And Dose estimation Citation Details In-Document Search Title: RADTRAD: A simplified model for RADionuclide...

  1. A kinetic model for anisotropic reactions in amorphous solids

    E-Print Network [OSTI]

    Hong, Wei

    , and does not need to introduce kinetic-dependent plasticity or modify basic thermodynamic quantities models either attribute such deformation to the plastic flow driven by the stress exceeding a non1 A kinetic model for anisotropic reactions in amorphous solids Wei Hong* Department of Aerospace

  2. The fundamental Diagram of Pedestrian Model with Slow Reaction

    E-Print Network [OSTI]

    Fang, Jun; Hu, Hao; Xu, Zhaohui; Li, Huan

    2015-01-01

    The slow-to-start models are a classical cellular automata model in simulating vehicle traffic. However, to our knowledge, the slow-to-start effect has not considered in modeling pedestrian dynamic. We verify the similar behavior between pedestrian and vehicle, and propose an new lattice gas (LG) model called the slow reaction (SR) model to describe the pedestrian's delayed reaction in single-file movement. We simulate and reproduce the Seyfried's field experiments at the research centre Julich, and use its empirical data to validate our SR model. We compare the SR model with the standard LG model. We test different probability of slow reaction ps in SR model and found the simulation data of ps=0.3 fit the empirical data best. The RMS error of mean velocity of SR model is smaller than that of standard LG model. In the range of ps=0.1~0.3, our fundamental diagram between velocity and density by simulation coincides with field experiments. The distribution of individual velocity in fundamental diagram in SR mod...

  3. Documentation of TRU biological transport model (BIOTRAN)

    SciTech Connect (OSTI)

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

    1980-01-01

    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.

  4. Adiabatic quantum-fluid transport models N. Ben Abdallah1

    E-Print Network [OSTI]

    Negulescu, Claudia

    Adiabatic quantum-fluid transport models N. Ben Abdallah1 , F. Mehats2 and C. Negulescu1 1 MIP quantum-fluid models are derived by means of a diffusion approxima- tion from adiabatic quantum-kinetic models. These models describe the electron transport of a bidimensional electron gas. Particles

  5. Model hydrocracking reactions over monometallic and bimetallic dispersed catalysts

    SciTech Connect (OSTI)

    Schmidt, E.; Song, C. [Penn State Univ., University Park, PA (United States)

    1994-12-31

    Coal liquefaction involves the cleavage of methylene and dimethylene bridges connecting polycyclic aromatic units. The selected compound for model reactions is 4-(1-naphthylmethyl)bibenzyl (NMBB). This work describes the synthesis and screening of several metallic complex precursors as dispersed catalysts for hydrocracking of NMBB.

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

    SciTech Connect (OSTI)

    Suh, Dong-Myung; Sun, Xin

    2013-09-01

    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.

  7. Mesoscopic modeling of liquid water transport in polymer electrolyte fuel cells

    SciTech Connect (OSTI)

    Mukherjee, Partha P [Los Alamos National Laboratory; Wang, Chao Yang [PENNSTATE UNIV.

    2008-01-01

    A key performance limitation in polymer electrolyte fuel cells (PEFC), manifested in terms of mass transport loss, originates from liquid water transport and resulting flooding phenomena in the constituent components. Liquid water leads to the coverage of the electrochemically active sites in the catalyst layer (CL) rendering reduced catalytic activity and blockage of the available pore space in the porous CL and fibrous gas diffusion layer (GDL) resulting in hindered oxygen transport to the active reaction sites. The cathode CL and the GDL therefore playa major role in the mass transport loss and hence in the water management of a PEFC. In this article, we present the development of a mesoscopic modeling formalism coupled with realistic microstructural delineation to study the profound influence of the pore structure and surface wettability on liquid water transport and interfacial dynamics in the PEFC catalyst layer and gas diffusion layer.

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

    E-Print Network [OSTI]

    Theodore E. Liolios

    2003-06-23

    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.

  9. Integration of Nontraditional Isotopic Systems Into Reaction...

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

    Nontraditional Isotopic Systems Into Reaction-Transport Models of EGS For Exploration, Evaluation of Water-Rock Interaction, and Impacts of Water Chemistry on Reservoir...

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

    E-Print Network [OSTI]

    C. A. Bertulani; A. Gade

    2006-04-12

    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.

  11. Using transport diagnostics to understand chemistry climate model ozone

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    Using transport diagnostics to understand chemistry climate model ozone simulations Article chemistry climate model ozone simulations. Journal of Geophysical Research - Atmospheres, 116 (D17). D17302 transport diagnostics to understand chemistry climate model ozone simulations S. E. Strahan,1 A. R. Douglass

  12. SOLVING VERTICAL TRANSPORT AND CHEMISTRY IN AIR POLLUTION MODELS

    E-Print Network [OSTI]

    Botchev, Mike

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

  13. An Updated Site Scale Saturated Zone Ground Water Transport Model...

    Office of Scientific and Technical Information (OSTI)

    An Updated Site Scale Saturated Zone Ground Water Transport Model for Yucca Mountain. Citation Details In-Document Search Title: An Updated Site Scale Saturated Zone Ground Water...

  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. Building robust chemical reaction mechanisms : next generation of automatic model construction software

    E-Print Network [OSTI]

    Song, Jing, 1972-

    2004-01-01

    Building proper reaction mechanisms is crucial to model the system dynamic properties for many industrial processes with complex chemical reaction phenomena. Because of the complexity of a reaction mechanism, computer-aided ...

  17. Spot Self-Replication for Reaction-Diffusion Models in

    E-Print Network [OSTI]

    Ward, Michael Jeffrey

    -Splitting: The ferrocyanide-iodate-sulphite reaction (Swinney et al, Nature, 1994), the chloride-dioxide-malonic acid reaction

  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--simulating groundwater flow and solute transport, with basic chemical reactions such as aqueous complexing, mineral systems [1]. Although these simplified groundwater models are still in wide use, advances in subsurface

  19. Diffusion-controlled reactions modeling in Geant4-DNA

    SciTech Connect (OSTI)

    Karamitros, M.; Luan, S.; Bernal, M.A.; Allison, J.; Baldacchino, G.; Davidkova, M.; Francis, Z.; Friedland, W.; Ivantchenko, V.; Ivantchenko, A.; Mantero, A.; Nieminem, P.; Santin, G.; Tran, H.N.; Stepan, V.; Incerti, S.

    2014-10-01

    Context Under irradiation, a biological system undergoes a cascade of chemical reactions that can lead to an alteration of its normal operation. There are different types of radiation and many competing reactions. As a result the kinetics of chemical species is extremely complex. The simulation becomes then a powerful tool which, by describing the basic principles of chemical reactions, can reveal the dynamics of the macroscopic system. To understand the dynamics of biological systems under radiation, since the 80s there have been on-going efforts carried out by several research groups to establish a mechanistic model that consists in describing all the physical, chemical and biological phenomena following the irradiation of single cells. This approach is generally divided into a succession of stages that follow each other in time: (1) the physical stage, where the ionizing particles interact directly with the biological material; (2) the physico-chemical stage, where the targeted molecules release their energy by dissociating, creating new chemical species; (3) the chemical stage, where the new chemical species interact with each other or with the biomolecules; (4) the biological stage, where the repairing mechanisms of the cell come into play. This article focuses on the modeling of the chemical stage. Method This article presents a general method of speeding-up chemical reaction simulations in fluids based on the Smoluchowski equation and Monte-Carlo methods, where all molecules are explicitly simulated and the solvent is treated as a continuum. The model describes diffusion-controlled reactions. This method has been implemented in Geant4-DNA. The keys to the new algorithm include: (1) the combination of a method to compute time steps dynamically with a Brownian bridge process to account for chemical reactions, which avoids costly fixed time step simulations; (2) a kd tree data structure for quickly locating, for a given molecule, its closest reactants. The performance advantage is presented in terms of complexity, and the accuracy of the new algorithm is demonstrated by simulating radiation chemistry in the context of the Geant4-DNA project. Application The time-dependent radiolytic yields of the main chemical species formed after irradiation are computed for incident protons at different energies (from 50 MeV to 500 keV). Both the time-evolution and energy dependency of the yields are discussed. The evolution, at one microsecond, of the yields of hydroxyls and solvated electrons with respect to the linear energy transfer is compared to theoretical and experimental data. According to our results, at high linear energy transfer, modeling radiation chemistry in the trading compartment representation might be adopted.

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

    SciTech Connect (OSTI)

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

    2009-01-01

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

  1. Integration of Groundwater Transport Models with Wireless Sensor Networks

    E-Print Network [OSTI]

    Han, Qi "Chee"

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

  2. A quantum energy transport model for semiconductor device simulation

    SciTech Connect (OSTI)

    Sho, Shohiro; Odanaka, Shinji

    2013-02-15

    This paper describes numerical methods for a quantum energy transport (QET) model in semiconductors, which is derived by using a diffusion scaling in the quantum hydrodynamic (QHD) model. We newly drive a four-moments QET model similar with a classical ET model. Space discretization is performed by a new set of unknown variables. Numerical stability and convergence are obtained by developing numerical schemes and an iterative solution method with a relaxation method. Numerical simulations of electron transport in a scaled MOSFET device are discussed. The QET model allows simulations of quantum confinement transport, and nonlocal and hot-carrier effects in scaled MOSFETs.

  3. A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,

    E-Print Network [OSTI]

    Nagurney, Anna

    of Operations & Information Management Isenberg School of Management University of Massachusetts AmherstA Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality of Massachusetts Amherst A Dynamic Network Oligopoly Model with Quality Competition #12;Acknowledgments

  4. A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,

    E-Print Network [OSTI]

    Nagurney, Anna

    and Operations Management Isenberg School of Management University of Massachusetts Amherst, Massachusetts 01003A Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality Network Oligopoly Model with Quality Competition #12;Acknowledgments This research was supported, in part

  5. A numerical model simulation of longshore transport for Galveston Island

    E-Print Network [OSTI]

    Gilbreath, Stephen Alexander

    1995-01-01

    The shoreline changes, deposition patterns, and longshore transport rates were calculated for the coast of Galveston Island using a numerical model simulation. The model only simulated changes due to waves creating longshore currents. East Beach...

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

    E-Print Network [OSTI]

    Kim, Dae Hong

    2010-10-12

    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, ...

  7. 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

    2013-09-06

    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.

  8. Modelling charge transfer reactions with the frozen density embedding formalism

    SciTech Connect (OSTI)

    Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Institute for Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany)

    2011-12-21

    The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionals are used the electronic couplings are grossly overestimated.

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

    E-Print Network [OSTI]

    Faghaninia, Alireza; Lo, Cynthia S

    2015-01-01

    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)

    2012-01-01

    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. 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

    2010-09-28

    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.

  12. 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

    2011-07-01

    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.

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

    E-Print Network [OSTI]

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

    2015-04-01

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

  14. Transport coefficients of a mesoscopic fluid dynamics model

    E-Print Network [OSTI]

    N. Kikuchi; C. M. Pooley; J. F. Ryder; J. M. Yeomans

    2003-02-21

    We investigate the properties of stochastic rotation dynamics (Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating hydrodynamics. Analytical results are given for the transport coefficients. We discuss the most efficient way of measuring the transport properties and obtain excellent agreement between the theoretical and numerical calculations.

  15. Modeling of Magnetic Nanoparticles Transport in Shale Reservoirs

    E-Print Network [OSTI]

    An, Cheng

    2014-12-18

    stimulated reservoir volume (SRV) from induced fractures play a critical role in significantly increasing well productivity. In this project, a mathematical model for simulating nanoparticle transport in shale reservoirs was developed. The simulator includes...

  16. Transportation system modeling using the High Level Architecture

    E-Print Network [OSTI]

    Melouk, Sharif

    2004-09-30

    support software in the transportation arena; (3) determine the usability of methods developed by the military to test for HLA compliance on traffic simulation models; and (4) examine the possibility of using the HLA to create Internet-based virtual...

  17. Deuteron-nucleus collisions in a multiphase transport model

    E-Print Network [OSTI]

    Lin, ZW; Ko, Che Ming.

    2003-01-01

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

  18. REPRESENTING AEROSOL DYNAMICS AND PROPERTIES IN CHEMICAL TRANSPORT MODELS BY THE METHOD OF MOMENTS

    E-Print Network [OSTI]

    shortwave (solar) radiation, affecting climate (Charlson et al., 1992; Schwartz, 1996) and visibility this distribution and its evolution in chemical transport models. Atmospheric chemical transport models to date

  19. Modeling Chemical Reactions with Single Reactant Specie Abhyudai Singh and Jo~ao Pedro Hespanha

    E-Print Network [OSTI]

    Hespanha, Joo Pedro

    Modeling Chemical Reactions with Single Reactant Specie Abhyudai Singh and Jo~ao Pedro Hespanha Abstract-- A procedure for constructing approximate stochastic models for chemical reactions involving involved in a chemical reaction as the continuous state of a polynomial Stochastic Hybrid System (p

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

    SciTech Connect (OSTI)

    1998-01-01

    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.

  1. A multi-pathway model for Photosynthetic reaction center

    E-Print Network [OSTI]

    M. Qin; H. Z Shen; X. X. Yi

    2015-06-29

    Charge separation in light-harvesting complexes occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine (QHE). Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem {\\rm II} reaction center (PS{\\rm II} RC) to describe the charge separation. Our model mainly considers two charge-separation pathways more than that in the published literature. The two pathways can interfere via cross-couplings and work together to enhance the charge-separation yields. We explore how these cross-couplings increase the current and voltage of the charge separation and discuss the advantages of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PS{\\rm II} RC and dephasing induced by environments is also explored, and extension from two pathways to multiple pathways is made. These results suggest that nature-mimicking architectures with engineered multiple pathways for charge separations might be better for artificial solar energy devices.

  2. A multi-pathway model for Photosynthetic reaction center

    E-Print Network [OSTI]

    Qin, M; Yi, X X

    2015-01-01

    Charge separation in light-harvesting complexes occurs in a pair of tightly coupled chlorophylls at the heart of photosynthetic reaction centers of both plants and bacteria. Recently it has been shown that quantum coherence can, in principle, enhance the efficiency of a solar cell, working like a quantum heat engine (QHE). Here, we propose a biological quantum heat engine (BQHE) motivated by Photosystem {\\rm II} reaction center (PS{\\rm II} RC) to describe the charge separation. Our model mainly considers two charge-separation pathways more than that in the published literature. The two pathways can interfere via cross-couplings and work together to enhance the charge-separation yields. We explore how these cross-couplings increase the current and voltage of the charge separation and discuss the advantages of multiple pathways in terms of current and power. The robustness of the BQHE against the charge recombination in natural PS{\\rm II} RC and dephasing induced by environments is also explored, and extension ...

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

    SciTech Connect (OSTI)

    Trowbridge, L.D.

    2000-04-01

    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.

  4. Modeling the Kinetics of Bimolecular Reactions Antonio Fernandez-Ramos

    E-Print Network [OSTI]

    Truhlar, Donald G

    -dependent energy transfer processes. The section on thermal reactions has a heavy emphasis on (generalized-Phase Thermal Reactions 4518 2.1. Thermodynamics: Enthalpies and Free Energies of Reaction 4518 2.2. Kinetics 4520 2.2.1. Arrhenius Parameters and Free Energy of Activation 4520 2.2.2. Collision Theory 4521 2

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

    SciTech Connect (OSTI)

    Yorstos, Yannis C.

    2003-03-19

    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.

  6. 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 ...

  7. A HIERARCHY OF EMPIRICAL MODELS OF PLASMA PROFILES AND TRANSPORT

    E-Print Network [OSTI]

    average density, #22; n e (in 10 19 =m 3 ), the absorbed power, P (in MW), the e#11;ective ion charge, ZA HIERARCHY OF EMPIRICAL MODELS OF PLASMA PROFILES AND TRANSPORT Kaya Imre and Kurt S. Riedel New, Oxon, OX14 3EA, UK Abstract Two families of statistical models of increasing statistical complexity

  8. 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

  9. Hybrid models of transport in crowded environments

    E-Print Network [OSTI]

    Battiato, Ilenia

    2010-01-01

    6.2.5 Hybrid algorithm . . . . . . . . . . . . . . .88 Chapter 5 Hybrid Model for Reactive Flow in a5.3.1 Hybrid validation . . . . . . . . . . . . . . . vii

  10. Multiple equilibria in complex chemical reaction networks: extensions to entrapped species models

    E-Print Network [OSTI]

    Craciun, Gheorghe

    Multiple equilibria in complex chemical reaction networks: extensions to entrapped species models G of complex chemical reaction networks, taken with mass-action kinetics, to admit multiple equilibria.) In both papers, it was understood that the reactions were taking place in the context of what chemical

  11. Log-Domain Circuit Models of Chemical Reactions Soumyajit Mandal and Rahul Sarpeshkar

    E-Print Network [OSTI]

    Sarpeshkar, Rahul

    Log-Domain Circuit Models of Chemical Reactions Soumyajit Mandal and Rahul Sarpeshkar Department to networks of chemical reactions. Our circuits can be used for transient and steady-state simulations the energy barrier of a chemical reaction, exponentially changing its speed. In an analogous fashion, gate

  12. Models for Multi-Specie Chemical Reactions Using Polynomial Stochastic Hybrid Systems

    E-Print Network [OSTI]

    Hespanha, Joo Pedro

    Models for Multi-Specie Chemical Reactions Using Polynomial Stochastic Hybrid Systems Abhyudai for chemical reactions is presented. This is done by representing the population of various species involved in a chemical reaction as the continuous state of a polynomial Stochastic Hybrid System (pSHS). An important

  13. Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model

    E-Print Network [OSTI]

    Podladchikov, Yuri

    Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model D. W. SCHMID,1 of the matrix that surrounds the reaction sites where the volume change takes place. Consequently, mineral reactions and the mechanical response of the rock matrix are coupled. A companion paper in this issue

  14. Model Discrimination of Chemical Reaction Networks by Linearization D. Georgiev, M. Fazel, and E. Klavins

    E-Print Network [OSTI]

    Fazel, Maryam

    Model Discrimination of Chemical Reaction Networks by Linearization D. Georgiev, M. Fazel, and E experiments that, with high probability, discriminate between competing models is desired. In particu- lar biochemical networks. Unfortunately, the model discrimination problem for such systems is computationally

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

    SciTech Connect (OSTI)

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

    2014-03-01

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

  16. Jet propagation within a Linearized Boltzmann Transport Model

    E-Print Network [OSTI]

    Luo, Tan; Wang, Xin-Nian; Zhu, Yan

    2015-01-01

    A Linear Boltzmann Transport (LBT) model has been developed for the study of jet propagation inside a quark-gluon plasma. Both leading and thermal recoiled partons are transported according to the Boltzmann equations to account for jet-induced medium excitations. In this talk, we present our study within the LBT model in which we implement the complete set of elastic parton scattering processes. We investigate elastic parton energy loss and their energy and length dependence. We further investigate elastic energy loss and transverse shape of reconstructed jets. Contributions from the recoiled thermal partons are found to have significant influences on the jet energy loss and transverse profile.

  17. Jet propagation within a Linearized Boltzmann Transport Model

    E-Print Network [OSTI]

    Tan Luo; Yayun He; Xin-Nian Wang; Yan Zhu

    2015-06-12

    A Linear Boltzmann Transport (LBT) model has been developed for the study of jet propagation inside a quark-gluon plasma. Both leading and thermal recoiled partons are transported according to the Boltzmann equations to account for jet-induced medium excitations. In this talk, we present our study within the LBT model in which we implement the complete set of elastic parton scattering processes. We investigate elastic parton energy loss and their energy and length dependence. We further investigate elastic energy loss and transverse shape of reconstructed jets. Contributions from the recoiled thermal partons are found to have significant influences on the jet energy loss and transverse profile.

  18. A Dual Regime Reactive Transport Model for Simulation of High Level Waste Tank Closure Scenarios - 13375

    SciTech Connect (OSTI)

    Sarkar, Sohini; Kosson, David S.; Brown, Kevin; Garrabrants, Andrew C.; Meeussen, Hans; Van der Sloot, Hans

    2013-07-01

    A numerical simulation framework is presented in this paper for estimating evolution of pH and release of major species from grout within high-level waste tanks after closure. This model was developed as part of the Cementitious Barriers Partnership. The reactive transport model consists of two parts - (1) transport of species, and (2) chemical reactions. The closure grout can be assumed to have varying extents of cracking and composition for performance assessment purposes. The partially or completely degraded grouted tank is idealized as a dual regime system comprising of a mobile region having solid materials with cracks and macro-pores, and an immobile/stagnant region having solid matrix with micropores. The transport profiles of the species are calculated by incorporating advection of species through the mobile region, diffusion of species through the immobile/stagnant region, and exchange of species between the mobile and immobile regions. A geochemical speciation code in conjunction with the pH dependent test data for a grout material is used to obtain a mineral set that best describes the trends in the test data of the major species. The dual regime reactive transport model predictions are compared with the release data from an up-flow column percolation test. The coupled model is then used to assess effects of crack state of the structure, rate and composition of the infiltrating water on the pH evolution at the grout-waste interface. The coupled reactive transport model developed in this work can be used as part of the performance assessment process for evaluating potential risks from leaching of a cracked tank containing elements of human health and environmental concern. (authors)

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

    SciTech Connect (OSTI)

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

    2011-01-01

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

  20. NearCoM-TVD --A quasi-3D nearshore circulation and sediment transport model

    E-Print Network [OSTI]

    Kirby, James T.

    NearCoM-TVD -- A quasi-3D nearshore circulation and sediment transport model Jia-Lin Chen , Fengyan: Nearshore community model TVD-scheme Sediment transport Sandbar migration The newly developed nearshore). For sediment transport applications, two sediment transport models are applied to pre- dict three sandbar

  1. Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemistry in the region of Iriduim and Gold

    SciTech Connect (OSTI)

    Hoffman, R D; Dietrich, F S; Kelley, K; Escher, J; Bauer, R; Mustafa, M

    2008-02-26

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from osmium (Z = 76) to gold (Z = 79). Of particular interest are the cross sections on Ir and Au including reactions on isomeric targets.

  2. A quasilinear model for solute transport under unsaturated flow

    SciTech Connect (OSTI)

    Houseworth, J.E.; Leem, J.

    2009-05-15

    We developed an analytical solution for solute transport under steady-state, two-dimensional, unsaturated flow and transport conditions for the investigation of high-level radioactive waste disposal. The two-dimensional, unsaturated flow problem is treated using the quasilinear flow method for a system with homogeneous material properties. Dispersion is modeled as isotropic and is proportional to the effective hydraulic conductivity. This leads to a quasilinear form for the transport problem in terms of a scalar potential that is analogous to the Kirchhoff potential for quasilinear flow. The solutions for both flow and transport scalar potentials take the form of Fourier series. The particular solution given here is for two sources of flow, with one source containing a dissolved solute. The solution method may easily be extended, however, for any combination of flow and solute sources under steady-state conditions. The analytical results for multidimensional solute transport problems, which previously could only be solved numerically, also offer an additional way to benchmark numerical solutions. An analytical solution for two-dimensional, steady-state solute transport under unsaturated flow conditions is presented. A specific case with two sources is solved but may be generalized to any combination of sources. The analytical results complement numerical solutions, which were previously required to solve this class of problems.

  3. MODELING OF CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION IN GROUNDWATER

    E-Print Network [OSTI]

    Boyer, Edmond

    1 MODELING OF CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION IN GROUNDWATER QUIOT Fabrice1 performed by 4 teams (ANTEA, ENSMP, ENVIROS and INERIS) to simulate a contamination of groundwater is the evaluation of the fate of pollutants in groundwaters and soils. This knowledge is based on the result

  4. 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.

    2013-09-01

    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.

  5. Analytical model for flux saturation in sediment transport

    E-Print Network [OSTI]

    Thomas Phtz; Eric J. R. Parteli; Jasper F. Kok; Hans J. Herrmann

    2015-08-21

    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.

  6. Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions for model systems

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions A general minimal model for proton-coupled electron transfer PCET reactions in solution is presented. This model consists of three coupled degrees of freedom that represent an electron, a proton, and a solvent

  7. Modeling light-driven proton pumps in artificial photosynthetic reaction centers

    E-Print Network [OSTI]

    Nori, Franco

    Modeling light-driven proton pumps in artificial photosynthetic reaction centers Pulak Kumar Ghosh in artificial reaction centers. The model contains a molecular triad with four electron states i.e., one donor transduction processes in the laboratory.17,912 A convenient approach to photosynthesis in artificial

  8. 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.

    2009-09-01

    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.

  9. 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 ...

  10. 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.

    1982-12-01

    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.

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

    SciTech Connect (OSTI)

    Not Available

    1994-03-01

    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.

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

    SciTech Connect (OSTI)

    Yortsos, Yanis C.

    2002-10-08

    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.

  13. Comparison of a radial fractional transport model with tokamak experiments

    SciTech Connect (OSTI)

    Kullberg, A. Morales, G. J.; Maggs, J. E.

    2014-03-15

    A radial fractional transport model [Kullberg et al., Phys. Rev. E 87, 052115 (2013)], that correctly incorporates the geometric effects of the domain near the origin and removes the singular behavior at the outer boundary, is compared to results of off-axis heating experiments performed in the Rijnhuizen Tokamak Project (RTP), ASDEX Upgrade, JET, and DIII-D tokamak devices. This comparative study provides an initial assessment of the presence of fractional transport phenomena in magnetic confinement experiments. It is found that the nonlocal radial model is robust in describing the steady-state temperature profiles from RTP, but for the propagation of heat waves in ASDEX Upgrade, JET, and DIII-D the model is not clearly superior to predictions based on Fick's law. However, this comparative study does indicate that the order of the fractional derivative, ?, is likely a function of radial position in the devices surveyed.

  14. Linked multicontinuum and crack tensor approach for modeling of coupled geomechanics, fluid flow and transport in fractured rock

    E-Print Network [OSTI]

    Rutqvist, J.

    2014-01-01

    porosity models for fluid transport in jointed rock. Journalof coupled fluid flow, solute transport, and geomechanics ingeomechanics, fluid flow and transport in fractured rock

  15. 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 the fluid portion of the model. Transport coefficients, source functions, and energy distributions for all field has motivated a num- ber of investigations into its effect on the `electron energy distribution

  16. Multiscale model reduction for shale gas transport in fractured media

    E-Print Network [OSTI]

    Akkutlu, I Y; Vasilyeva, Maria

    2015-01-01

    In this paper, we develop a multiscale model reduction technique that describes shale gas transport in fractured media. Due to the pore-scale heterogeneities and processes, we use upscaled models to describe the matrix. We follow our previous work \\cite{aes14}, where we derived an upscaled model in the form of generalized nonlinear diffusion model to describe the effects of kerogen. To model the interaction between the matrix and the fractures, we use Generalized Multiscale Finite Element Method. In this approach, the matrix and the fracture interaction is modeled via local multiscale basis functions. We developed the GMsFEM and applied for linear flows with horizontal or vertical fracture orientations on a Cartesian fine grid. In this paper, we consider arbitrary fracture orientations and use triangular fine grid and developed GMsFEM for nonlinear flows. Moreover, we develop online basis function strategies to adaptively improve the convergence. The number of multiscale basis functions in each coarse region ...

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

    E-Print Network [OSTI]

    Theodore Liolios

    2003-05-09

    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.

  18. Advancements in the ADAPT Photospheric Flux Transport Model

    E-Print Network [OSTI]

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

    2015-04-08

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

  19. Data Assimilation in the ADAPT Photospheric Flux Transport Model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

    2015-03-17

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

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

    Energy Savers [EERE]

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

  1. Modeling of contaminant transport in underground coal gasification

    SciTech Connect (OSTI)

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

    2009-01-15

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

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

    SciTech Connect (OSTI)

    Meneghini, O.; Luna, C. J.; Smith, S. P.; Lao, L. L.

    2014-06-15

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

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

    E-Print Network [OSTI]

    Ren, Kui

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

  4. 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

  5. Theoretical predictions of experimental observables sensitive to the symmetry energy: Results of the SMF transport model

    E-Print Network [OSTI]

    Maria Colonna; Virgil Baran; Massimo Di Toro

    2013-12-03

    In the framework of mean-field based transport approaches, we discuss recent results concerning heavy ion reactions between charge asymmetric systems, from low up to intermediate energies. We focus on isospin sensitive observables, aiming at extracting information on the density dependence of the isovector part of the nuclear effective interaction and of the nuclear symmetry energy. For reactions close to the Coulomb barrier, we explore the structure of collective dipole oscillations, rather sensitive to the low-density behavior of the symmetry energy. In the Fermi energy regime, we investigate the interplay between dissipation mechanisms, fragmentation and isospin effects. At intermediate energies, where regions with higher density and momentum are reached, we discuss collective flows and their sensitivity to the momentum dependence of the isovector interaction channel, which determines the splitting of neutron and proton effective masses. Finally, we also discuss the isospin effect on the possible phase transition from nucleonic matter to quark matter. Results are critically reviewed, also trying to establish a link, when possible, with the outcome of other transport models.

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

    E-Print Network [OSTI]

    Lu, Zhiming

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

  7. Mesoscopic modeling of stochastic reaction-diffusion kinetics in the subdiffusive regime

    E-Print Network [OSTI]

    Emilie Blanc; Stefan Engblom; Andreas Hellander; Per Ltstedt

    2015-03-24

    Subdiffusion has been proposed as an explanation of various kinetic phenomena inside living cells. In order to fascilitate large-scale computational studies of subdiffusive chemical processes, we extend a recently suggested mesoscopic model of subdiffusion into an accurate and consistent reaction-subdiffusion computational framework. Two different possible models of chemical reaction are revealed and some basic dynamic properties are derived. In certain cases those mesoscopic models have a direct interpretation at the macroscopic level as fractional partial differential equations in a bounded time interval. Through analysis and numerical experiments we estimate the macroscopic effects of reactions under subdiffusive mixing. The models display properties observed also in experiments: for a short time interval the behavior of the diffusion and the reaction is ordinary, in an intermediate interval the behavior is anomalous, and at long times the behavior is ordinary again.

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

    SciTech Connect (OSTI)

    1998-01-01

    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.

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

    E-Print Network [OSTI]

    G. Gangopadhyay

    2010-08-05

    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.

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

    SciTech Connect (OSTI)

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

    2006-11-15

    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.

  11. Temperature dependent transport coefficients in a dynamical holographic QCD model

    E-Print Network [OSTI]

    Danning Li; Song He; Mei Huang

    2014-11-19

    We investigate temperature dependent behavior of various transport coefficients in a dynamical holographical QCD model. We show the nontrivial temperature dependent behavior of the transport coefficients, like bulk viscosity, electric conductivity as well as jet quenching parameter, and it is found that all these quantities reveal information of the phase transition. Furthermore, with introducing higher derivative corrections in 5D gravity, the shear viscosity over entropy density ratio also shows a valley around phase transition, and it is found that the shear viscosity over entropy density ratio times the jet quenching over temperature cubic ratio almost remains as a constant above phase transition, and the value is two times larger than the perturbative result in Phys.Rev.Lett.99.192301(2007).

  12. Turbulence transport modeling of the temporal outer heliosphere

    SciTech Connect (OSTI)

    Adhikari, L.; Zank, G. P.; Hu, Q.; Dosch, A.

    2014-09-20

    The solar wind can be regarded as a turbulent magnetofluid, evolving in an expanding solar wind and subject to turbulent driving by a variety of in situ sources. Furthermore, the solar wind and the drivers of turbulence are highly time-dependent and change with solar cycle. Turbulence transport models describing low-frequency magnetic and velocity fluctuations in the solar wind have so far neglected solar cycle effects. Here we consider the effects of solar cycle variability on a turbulence transport model developed by Zank et al. This model is appropriate for the solar wind beyond about 1 AU, and extensions have described the steady-state dependence of the magnetic energy density fluctuations, correlation length, and solar wind temperature throughout the outer heliosphere. We find that the temporal solar wind introduces a periodic variability, particularly beyond ?10 AU, in the magnetic energy density fluctuations, correlation length, and solar wind temperature. The variability is insufficient to account for the full observed variability in these quantities, but we find that the time-dependent solutions trace the steady-state solutions quite well, suggesting that the steady-state models are reasonable first approximations.

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

    E-Print Network [OSTI]

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

    2007-01-01

    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 ...

  14. THE LOS ALAMOS NATIONAL LABORATORY ATMOSPHERIC TRANSPORT AND DIFFUSION MODELS

    SciTech Connect (OSTI)

    M. WILLIAMS

    1999-08-01

    The LANL atmospheric transport and diffusion models are composed of two state-of-the-art computer codes. The first is an atmospheric wind model called HOThlAC, Higher Order Turbulence Model for Atmospheric circulations. HOTMAC generates wind and turbulence fields by solving a set of atmospheric dynamic equations. The second is an atmospheric diffusion model called RAPTAD, Random Particle Transport And Diffusion. RAPTAD uses the wind and turbulence output from HOTMAC to compute particle trajectories and concentration at any location downwind from a source. Both of these models, originally developed as research codes on supercomputers, have been modified to run on microcomputers. Because the capability of microcomputers is advancing so rapidly, the expectation is that they will eventually become as good as today's supercomputers. Now both models are run on desktop or deskside computers, such as an IBM PC/AT with an Opus Pm 350-32 bit coprocessor board and a SUN workstation. Codes have also been modified so that high level graphics, NCAR Graphics, of the output from both models are displayed on the desktop computer monitors and plotted on a laser printer. Two programs, HOTPLT and RAPLOT, produce wind vector plots of the output from HOTMAC and particle trajectory plots of the output from RAPTAD, respectively. A third CONPLT provides concentration contour plots. Section II describes step-by-step operational procedures, specifically for a SUN-4 desk side computer, on how to run main programs HOTMAC and RAPTAD, and graphics programs to display the results. Governing equations, boundary conditions and initial values of HOTMAC and RAPTAD are discussed in Section III. Finite-difference representations of the governing equations, numerical solution procedures, and a grid system are given in Section IV.

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

    SciTech Connect (OSTI)

    1997-02-01

    Over the past year, several modifications have been made to the NEMS Transportation Model, incorporating greater levels of detail and analysis in modules previously represented in the aggregate or under a profusion of simplifying assumptions. This document is intended to amend those sections of the Model Documentation Report (MDR) which describe these superseded modules. Significant changes have been implemented in the LDV Fuel Economy Model, the Alternative Fuel Vehicle Model, the LDV Fleet Module, and the Highway Freight Model. The relevant sections of the MDR have been extracted from the original document, amended, and are presented in the following pages. A brief summary of the modifications follows: In the Fuel Economy Model, modifications have been made which permit the user to employ more optimistic assumptions about the commercial viability and impact of selected technological improvements. This model also explicitly calculates the fuel economy of an array of alternative fuel vehicles (AFV`s) which are subsequently used in the estimation of vehicle sales. In the Alternative Fuel Vehicle Model, the results of the Fuel Economy Model have been incorporated, and the program flows have been modified to reflect that fact. In the Light Duty Vehicle Fleet Module, the sales of vehicles to fleets of various size are endogenously calculated in order to provide a more detailed estimate of the impacts of EPACT legislation on the sales of AFV`s to fleets. In the Highway Freight Model, the previous aggregate estimation has been replaced by a detailed Freight Truck Stock Model, where travel patterns, efficiencies, and energy intensities are estimated by industrial grouping. Several appendices are provided at the end of this document, containing data tables and supplementary descriptions of the model development process which are not integral to an understanding of the overall model structure.

  16. Modeling interfacial area transport in multi-fluid systems

    SciTech Connect (OSTI)

    Yarbro, S.L.

    1996-11-01

    Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacial area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.

  17. CONTINUOUS TIME MARKOV CHAIN MODELS FOR CHEMICAL REACTION NETWORKS

    E-Print Network [OSTI]

    Anderson, David F.

    classifications. 65L05, 65L06, 65L80, 90C30, 80A30 1. Introduction. The microscopic modeling of the dynamics

  18. Reactive transport modeling of stable carbon isotope fractionation in a multi-phase multi-component system during carbon sequestration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Shuo; DePaolo, Donald J.; Zheng, Liange; Mayer, Bernhard

    2014-12-31

    Carbon stable isotopes can be used in characterization and monitoring of CO2 sequestration sites to track the migration of the CO2 plume and identify leakage sources, and to evaluate the chemical reactions that take place in the CO2-water-rock system. However, there are few tools available to incorporate stable isotope information into flow and transport codes used for CO2 sequestration problems. We present a numerical tool for modeling the transport of stable carbon isotopes in multiphase reactive systems relevant to geologic carbon sequestration. The code is an extension of the reactive transport code TOUGHREACT. The transport module of TOUGHREACT was modifiedmoreto include separate isotopic species of CO2 gas and dissolved inorganic carbon (CO2, CO32-, HCO3-,). Any process of transport or reaction influencing a given carbon species also influences its isotopic ratio. Isotopic fractionation is thus fully integrated within the dynamic system. The chemical module and database have been expanded to include isotopic exchange and fractionation between the carbon species in both gas and aqueous phases. The performance of the code is verified by modeling ideal systems and comparing with theoretical results. Efforts are also made to fit field data from the Pembina CO2 injection project in Canada. We show that the exchange of carbon isotopes between dissolved and gaseous carbon species combined with fluid flow and transport, produce isotopic effects that are significantly different from simple two-component mixing. These effects are important for understanding the isotopic variations observed in field demonstrations.less

  19. Reactive transport modeling of stable carbon isotope fractionation in a multi-phase multi-component system during carbon sequestration

    SciTech Connect (OSTI)

    Zhang, Shuo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); DePaolo, Donald J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mayer, Bernhard [Univ. of Calgary (Canada). Dept. of Geosciences

    2014-12-31

    Carbon stable isotopes can be used in characterization and monitoring of CO2 sequestration sites to track the migration of the CO2 plume and identify leakage sources, and to evaluate the chemical reactions that take place in the CO2-water-rock system. However, there are few tools available to incorporate stable isotope information into flow and transport codes used for CO2 sequestration problems. We present a numerical tool for modeling the transport of stable carbon isotopes in multiphase reactive systems relevant to geologic carbon sequestration. The code is an extension of the reactive transport code TOUGHREACT. The transport module of TOUGHREACT was modified to include separate isotopic species of CO2 gas and dissolved inorganic carbon (CO2, CO32-, HCO3-,). Any process of transport or reaction influencing a given carbon species also influences its isotopic ratio. Isotopic fractionation is thus fully integrated within the dynamic system. The chemical module and database have been expanded to include isotopic exchange and fractionation between the carbon species in both gas and aqueous phases. The performance of the code is verified by modeling ideal systems and comparing with theoretical results. Efforts are also made to fit field data from the Pembina CO2 injection project in Canada. We show that the exchange of carbon isotopes between dissolved and gaseous carbon species combined with fluid flow and transport, produce isotopic effects that are significantly different from simple two-component mixing. These effects are important for understanding the isotopic variations observed in field demonstrations.

  20. Thermoelectric transport in the coupled valence-band model

    E-Print Network [OSTI]

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

    2011-01-01

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

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

    E-Print Network [OSTI]

    Franchi, Jacques

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

  2. 3.3 SEDIMENT SOURCES, TRANSPORT PROCESSES AND MODELING APPROACHES by Michael Church

    E-Print Network [OSTI]

    63 3.3 SEDIMENT SOURCES, TRANSPORT PROCESSES AND MODELING APPROACHES 3.3 by Michael Church, Environment Canada, Burlington, Ont. SEDIMENT SOURCES, TRANSPORT PROCESSES, AND MODELING APPROACHES FOR THE FRASER RIVER A thorough understanding of sediment sources and transport processes in rivers is essential

  3. A New Model of Fine Sediment Transport For the Fraser River

    E-Print Network [OSTI]

    #12;A New Model of Fine Sediment Transport For the Fraser River DOE FRAP 1996-17 Prepared for Fine sediments of the Fraser River play an important role in the transportation of contaminants ACTION PLAN. The existing models of fine sediment transport assume that the fine sediments behave

  4. 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

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

    E-Print Network [OSTI]

    Clement, Prabhakar

    Benchmarking a Visual-Basic based multi-component one-dimensional reactive transport modeling tool Jagadish Torlapati 1 , T. Prabhakar Clement n Department of Civil Engineering, Auburn University, Auburn transport Bioremediation Geochemical transport Numerical model a b s t r a c t We present the details

  6. Temperature Modeling for Reaction Development in Microwave-Assisted Chemistry

    E-Print Network [OSTI]

    Yakovlev, Vadim

    by measurements) is proposed to verify the effect of convection observed in the reactor. The developed principles-scale resonator-type reactor in a 3D model capable of monitoring electromagnetic and thermal processes can be used in the models of other reactors to help with key developments in microwave

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

    SciTech Connect (OSTI)

    Rothman, A.B.

    1996-02-01

    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}.

  8. A Finite Strain Model of Stress, Diffusion, Plastic Flow and Electrochemical Reactions in a Lithium-ion Half-cell

    E-Print Network [OSTI]

    Bower, Allan F; Sethuraman, Vijay A; 10.1016/j.jmps.2011.01.003

    2011-01-01

    We formulate the continuum field equations and constitutive equations that govern deformation, stress, and electric current flow in a Li-ion half-cell. The model considers mass transport through the system, deformation and stress in the anode and cathode, electrostatic fields, as well as the electrochemical reactions at the electrode/electrolyte interfaces. It extends existing analyses by accounting for the effects of finite strains and plastic flow in the electrodes, and by exploring in detail the role of stress in the electrochemical reactions at the electrode-electrolyte interfaces. In particular, we find that that stress directly influences the rest potential at the interface, so that a term involving stress must be added to the Nernst equation if the stress in the solid is significant. The model is used to predict the variation of stress and electric potential in a model 1-D half-cell, consisting of a thin film of Si on a rigid substrate, a fluid electrolyte layer, and a solid Li cathode. The predicted c...

  9. Modelling Heat Transport Across Nano-scale Material Interfaces for Next-generation Electronic Devices

    E-Print Network [OSTI]

    Milgram, Paul

    ) thermal boundary resistance between two dissimilar semiconductor materials using a combinationModelling Heat Transport Across Nano-scale Material Interfaces for Next-generation Electronic) with customized thermal transport properties. The scattering of thermal energy carriers at fabricated interfaces

  10. Solar cycle prediction using precursors and flux transport models

    E-Print Network [OSTI]

    R. Cameron; M. Schuessler

    2006-12-22

    We study the origin of the predictive skill of some methods to forecast the strength of solar activity cycles. A simple flux transport model for the azimuthally averaged radial magnetic field at the solar surface is used, which contains a source term describing the emergence of new flux based on observational sunspot data. We consider the magnetic flux diffusing over the equator as a predictor, since this quantity is directly related to the global dipole field from which a Babcock-Leighton dynamo generates the toroidal field for the next activity cycle. If the source is represented schematically by a narrow activity belt drifting with constant speed over a fixed range of latitudes between activity minima, our predictor shows considerable predictive skill with correlation coefficients up to 0.95 for past cycles. However, the predictive skill is completely lost when the actually observed emergence latitudes are used. This result originates from the fact that the precursor amplitude is determined by the sunspot activity a few years before solar minimum. Since stronger cycles tend to rise faster to their maximum activity (known as the Waldmeier effect), the temporal overlapping of cycles leads to a shift of the minimum epochs that depends on the strength of the following cycle. This information is picked up by precursor methods and also by our flux transport model with a schematic source. Therefore, their predictive skill does not require a memory, i.e., a physical connection between the surface manifestations of subsequent activity cycles.

  11. A physical model for seismic noise generation from sediment transport in rivers

    E-Print Network [OSTI]

    Tsai, Victor C.

    A physical model for seismic noise generation from sediment transport in rivers Victor C. Tsai,1 of seismic noise near rivers can help provide such measurements, but the lack of models linking observed model to describe the seismic noise induced by the transport of sediment in rivers. The model provides

  12. Modeling of a Nickel-Hydrogen Cell Phase Reactions in the Nickel Active Material

    E-Print Network [OSTI]

    developed high-energy-density batteries, e.g., the nickel-metal hydride battery and the lithium-ion batteryModeling of a Nickel-Hydrogen Cell Phase Reactions in the Nickel Active Material B. Wu and R. E of South Carolina, Columbia, South Carolina 29208, USA A nonisothermal model of a nickel-hydrogen cell has

  13. Molecular-level simulations of chemical reaction equilibrium and diffusion in slit and cylindrical nanopores: model dimerisation reactions

    E-Print Network [OSTI]

    Lisal, Martin

    Molecular-level simulations of chemical reaction equilibrium and diffusion in slit and cylindrical study of the effects of confinement on chemical reaction equilibrium and diffusion in both slit nanopores 1. Introduction The behaviour of chemical reactions confined in nanopores is of extensive

  14. 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.

    1981-01-01

    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.

  15. TOUGH2. Unsaturated Groundwater and Heat Transport Model

    SciTech Connect (OSTI)

    Pruess, K. [Lawrence Berkeley National Lab., CA (United States)

    1991-05-01

    TOUGH2 is a new and improved version of TOUGH. TOUGH2 offers added capabilities and user features, including the flexibility to handle different fluid mixtures (water, water with tracer; water, CO2; water, air; water, air, with vapor pressure lowering and water, hydrogen), facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. TOUGH2 is a multi-dimensional numerical model for simulating the coupled transport of water, vapor, air, and heat in porous and fractured media. The program provides options for specifying injection or withdrawal of heat and fluids. Although primarily designed for studies of high-level nuclear waste isolation in partially saturated geological media, it should also be useful for a wider range of problems in heat and moisture transfer, and in the drying of porous materials. For example, geothermal reservoir simulation problems can be handled simply by setting the air mass function equal to zero on input. The TOUGH2 simulator was developed for problems involving strongly heat-driven flow. To describe these phenomena a multi-phase approach to fluid and heat flow is used, which fully accounts for the movement of gaseous and liquid phases, their transport of latent and sensible heat, and phase transitions between liquid and vapor. TOUGH2 takes account of fluid flow in both liquid and gaseous phases occurring under pressure, viscous, and gravity forces according to Darcy`s law. Interference between the phases is represented by means of relative permeability functions. The code handles binary, but not Knudsen, diffusion in the gas phase and capillary and phase adsorption effects for the liquid phase. Heat transport occurs by means of conduction with thermal conductivity dependent on water saturation, convection, and binary diffusion, which includes both sensible and latent heat.

  16. Direct Internal Reformation and Mass Transport in the Solid Oxide Fuel Cell Anode: A Pore-Scale Lattice Boltzmann Study with Detailed Reaction Kinetics

    SciTech Connect (OSTI)

    Grew, Kyle N.; Joshi, Abhijit S.; Chiu, W. K. S.

    2010-11-30

    The solid oxide fuel cell (SOFC) allows the conversion of chemical energy that is stored in a given fuel, including light hydrocarbons, to electrical power. Hydrocarbon fuels, such as methane, are logistically favourable and provide high energy densities. However, the use of these fuels often results in a decreased efficiency and life. An improved understanding of the reactive flow in the SOFC anode can help address these issues. In this study, the transport and heterogeneous internal reformation of a methane based fuel is addressed. The effect of the SOFC anode's complex structure on transport and reactions is shown to exhibit a complicated interplay between the local molar concentrations and the anode structure. Strong coupling between the phenomenological microstructures and local reformation reaction rates are recognised in this study, suggesting the extension to actual microstructures may provide new insights into the reformation processes.

  17. 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.

    2011-07-15

    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.

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

    E-Print Network [OSTI]

    Shenshen Wang; Peter G. Wolynes

    2014-12-19

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

  19. Pore Models Track Reactions in Underground Carbon Capture

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesseworkSURVEYI/OPerformancePi Day Pi Day PiPolaronSustainabilityPore Models

  20. Understanding composite explosive energetics: 3, Reactive flow modeling of aluminum reaction kinetics in PETN and TNT

    SciTech Connect (OSTI)

    Tao, W.C.; Tarver, C.M.; Ornellas, D.L.

    1991-12-06

    Using Fabry-Perot interferometry techniques, we have determined that early time rate of energy release from detonating PETN and TNT explosives filled with 5 and 10 wt % of either 5 {mu}m of 18 {mu}m spherical aluminum (Al) particles. From the measured particle velocity data, we are able to infer the reaction rate of aluminum with the detonation products, and calculate the extent of reaction 1--3 {mu}s after the detonation. We observed that a substantional portion of the aluminum metal in all of the PETN and TNE formulations reacted within the timeframe of the one-dimensional experiment. In the PETN formulation filed with 5 wt % of 5 {mu}m aluminum, all of the metal reacted within 1.5 {mu}s, resulting in an increase of 22% in energy compared to pure PETN. A reactive-flow hydrodynamic model based on the Zeldovich-von Neumann-Doring (ZND) description of the reaction zone and subsequent reaction produce expansion (Taylor wave) is used to interpret the reaction rate of the aluminum particles with detonation product gases. The diffusion-controlled reaction mechanism for aluminum and the global kinetic parameters used in the model have been found to be consistent for all the PETN and TNT formulations.

  1. A saddle in a corner - a model of collinear triatomic chemical reactions

    E-Print Network [OSTI]

    L. Lerman; V. Rom-Kedar

    2011-11-08

    A geometrical model which captures the main ingredients governing atom-diatom collinear chemical reactions is proposed. This model is neither near-integrable nor hyperbolic, yet it is amenable to analysis using a combination of the recently developed tools for studying systems with steep potentials and the study of the phase space structure near a center-saddle equilibrium. The nontrivial dependence of the reaction rates on parameters, initial conditions and energy is thus qualitatively explained. Conditions under which the phase space transition state theory assumptions are satisfied and conditions under which these fail are derived.

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

    E-Print Network [OSTI]

    Sarah Klein; Ccile Appert-Rolland; Ludger Santen

    2014-07-16

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

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

    SciTech Connect (OSTI)

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

    1995-12-01

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

  4. A network model for fluid transport through sea ice A. JABINI,1,2

    E-Print Network [OSTI]

    Golden, Kenneth M.

    A network model for fluid transport through sea ice J. ZHU,1 A. JABINI,1,2 K.M. GOLDEN,1 H. EICKEN, particularly in the Antarctic (Ackley and others, 1995; Maksym and Jeffries, 2001). Fluid transport through sea of dissolved organic matter (Lizotte, 2003). While fluid transport controls a broad range of sea-ice processes

  5. Multicomponent ballistic transport in narrow single wall carbon nanotubes: Analytic model and molecular dynamics simulations

    E-Print Network [OSTI]

    Adler, Joan

    online 27 January 2011) The transport of gas mixtures through molecular-sieve membranes such as narrow The transport of gas mixtures through molecular-sieve membranes and catalysts has been a subject of intensive inMulticomponent ballistic transport in narrow single wall carbon nanotubes: Analytic model

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

    E-Print Network [OSTI]

    Kassens, Eva

    2009-01-01

    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 ...

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

    E-Print Network [OSTI]

    Vlad, Gregorio

    . INTRODUCTION Predictions of ITER based on validated 1-D transport models would provide: 1) a physical research programs. Many transport models have been partially tested against tokamak data [1]. In order to establish how well each model represents the wide range of existing tokamak data we have developed the ITER

  8. 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

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

    E-Print Network [OSTI]

    Chipperfield, Martyn

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

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

    E-Print Network [OSTI]

    Struchtrup, Henning

    Transport Phenomena in Polymer Electrolyte Membranes II. Binary Friction Membrane Model J. Fimrite by the need for improved and more gen- eral models to represent transport phenomena within polymer elec dynamic models required for fundamental simulation of in situ processes that are difficult to ob- serve

  11. d+Au Collisions from A MultiPhase Transport Model

    E-Print Network [OSTI]

    Lin, Zi-wei

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

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

    SciTech Connect (OSTI)

    A. Hassan; J. Chapman

    2008-11-01

    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

  13. 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

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

    E-Print Network [OSTI]

    Scora, George Alexander

    2011-01-01

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

  15. Modeling studies of mountain-scale radionuclide transport in the unsaturated zone at Yucca Mountain, Nevada

    E-Print Network [OSTI]

    Moridis, George J.; Seol, Yongkoo; Wu, Yu-Shu

    2003-01-01

    Investigations at Yucca Mountain - The Potential Repositoryin the Unsaturated Zone, Yucca Mountain, Nevada, ResourcesMODELING STUDIES OF MOUNTAIN-SCALE RADIONUCLIDE TRANSPORT IN

  16. Incorporating Yellow-Page Databases in GIS-Based Transportation Models

    E-Print Network [OSTI]

    Lee, Ming S.; McNally, Michael G.

    1998-01-01

    travel behavior using GIS. Master Thesis, The Pennsylvaniatransportation planning using GIS. Paper Presented at theYellow-Page Databases in GIS-Based Transportation Models

  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

    2015-01-01

    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. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

    SciTech Connect (OSTI)

    Pierce, Eric M [ORNL; Frugier, Pierre [CEA Marcoule DEN Laboratoire dtude du Comportement Long Terme (France); Criscenti, Louise J [Sandia National Laboratory (SNL); Kwon, Kideok [Sandia National Laboratory (SNL); Kerisit, Sebastien [Pacific Northwest National Laboratory (PNNL)

    2014-01-01

    Describing the reactions that occur at the glass-water interface and control the development of the altered layer constitutes one of the main scientific challenges impeding existing models from providing accurate radionuclide release estimates. Radionuclide release estimates are a critical component of the safety basis for geologic repositories. The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products) represents a complex region, both physically and chemically, sandwiched between two distinct boundaries pristine glass surface at the inner most interface and aqueous solution at the outer most interface. Computational models, spanning different length and time-scales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include geochemical simulations [i.e., classical reaction path simulations and glass reactivity in allowance for alteration layer (GRAAL) simulations], Monte Carlo simulations, and Molecular Dynamics methods. Discussed in this manuscript are the advances and limitations of each modeling approach placed in the context of the glass-water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers.

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

    SciTech Connect (OSTI)

    1998-01-01

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

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

    SciTech Connect (OSTI)

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

    2009-12-15

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

  1. 2D numerical simulation of the MEP energy-transport model with a finite difference scheme

    SciTech Connect (OSTI)

    Romano, V. . E-mail: romano@dmi.unict.it

    2007-02-10

    A finite difference scheme of Scharfetter-Gummel type is used to simulate a consistent energy-transport model for electron transport in semiconductors devices, free of any fitting parameters, formulated on the basis of the maximum entropy principle. Simulations of silicon n{sup +}-n-n{sup +} diodes, 2D-MESFET and 2D-MOSFET and comparisons with the results obtained by a direct simulation of the Boltzmann transport equation and with other energy-transport models, known in the literature, show the validity of the model and the robustness of the numerical scheme.

  2. 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, ...

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

    E-Print Network [OSTI]

    Pongsaksawad, Wanida

    2006-01-01

    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 ...

  4. A generic model for transport in turbulent shear flows

    SciTech Connect (OSTI)

    Newton, Andrew P. L.; Kim, Eun-Jin [Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH (United Kingdom)

    2011-05-15

    Turbulence regulation by large-scale shear flows is crucial for a predictive modeling of transport in plasma. In this paper the suppression of turbulent transport by large-scale flows is studied numerically by measuring the turbulent diffusion D{sub t} and scalar amplitude of decaying passive scalar fields n{sup '} advected by various turbulent flows. Both uniform flows and shear flows are shown to suppress turbulence causing the quenching in transport and turbulence amplitude. The uniform flows U{sub 0}={Lambda}y with the advection rate {Lambda} in the case of a finite correlated forcing with {tau}{sub F}=1 gives rise to the advection/sweeping effect which suppresses D{sub t}, and as {proportional_to}{Lambda}{sup -2} for {Lambda}>>{tau}{sub F}{sup -1}. In contrast, no influence of the uniform flow is found in the case of a short correlated forcing {tau}{sub F}{yields}0 due to Galilean invariance. For the shear flow U{sub 0}={Omega}sinxy ({Omega}= constant shearing rate) with the appropriate choice of the forcing ({tau}{sub F}{yields}0) the nature of transport suppression is shown to crucially depend on the properties of the turbulence. Specifically, for prescribed turbulence with a short correlation time {tau}{sub c}={tau}{sub F}<<{Omega}{sup -1}, the turbulence statistics scale as D{sub t{proportional_to}{Omega}}{sup -0.02}, {proportional_to}{Omega}{sup -0.62} and cross-phase cos{theta}{proportional_to}{Omega}{sup 0.29}. For consistently evolved turbulence with a finite correlation time {tau}{sub c{>=}{Omega}}{sup -1}, turbulence statistics are suppressed more strongly as D{sub t{proportional_to}{Omega}}{sup -1.75}, {proportional_to}{Omega}{sup -2.41}, {proportional_to}{Omega}{sup -0.65} and <{omega}{sup '2}>{proportional_to}{Omega}{sup -0.50}. A novel renormalization scheme is then introduced to rescale our results into the regime within which the kinetic energy and enstrophy are unchanged by shear flow. This allows our numerical results to closely match previous analytical predictions [E. Kim, Mod. Phys. Lett. B 18, 1 (2004)] and to understand different experimental scalings observed in laboratory plasmas. Furthermore, D{sub t} is found to be related to by {proportional_to}D{sub t}/D{sub {Omega}}, where D{sub {Omega}}{proportional_to}{Omega}{sup (2/3)} is the shear accelerated diffusion of n{sup '} with an interesting scaling cos{theta}{proportional_to}{radical}(D{sub t}D{sub {Omega}}).

  5. A unified model of electroporation and molecular transport

    E-Print Network [OSTI]

    Smith, Kyle Christopher

    2011-01-01

    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 ...

  6. Modeling Interfacial Glass-Water Reactions: Recent Advances and Current Limitations

    SciTech Connect (OSTI)

    Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; Kwon, K. D.; Kerisit, Sebastien N.

    2014-07-12

    The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products)represents a complex region, both physically and chemically, sandwiched between two distinct boundaries - pristine glass surface at the inner most interface and aqueous solution at the outer most. The physico-chemical processes that control the development of this region have a significant impact on the long-term glass-water reaction. Computational models, spanning different length and time-scales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the pore-scale changes that occur as the system evolves. These modeling approaches include Geochemical Reaction Path simulations, Glass Reactivity in Allowance for Alteration Layer simulations, Monte Carlo simulations, and Molecular Dynamics methods. Discussed in this manuscript are the advances and limitations of each modeling approach placed in the context of the glass water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers; thus providing the fundamental data needed to develop pore-scale equations that enable more accurate predictions of nuclear waste glass corrosion in a geologic repository.

  7. A Two-component Transport Model for Solar Wind Fluctuations: Waves plus Quasi-2D Turbulence

    E-Print Network [OSTI]

    Oughton, Sean

    component. Thus, it would seem appropriate, and advantageous, to develop an energy-containing style modelA Two-component Transport Model for Solar Wind Fluctuations: Waves plus Quasi-2D Turbulence Sean for the transport of solar wind fluctuations, based on the assumption that they can be well-represented using two

  8. 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

  9. ITER predictions using the GYRO verified and experimentally validated trapped gyro-Landau fluid transport model

    E-Print Network [OSTI]

    Budny, Robert

    predictions using the GYRO verified and experimentally validated trapped gyro-Landau fluid transport model JITER predictions using the GYRO verified and experimentally validated trapped gyro-Landau fluid transport model This article has been downloaded from IOPscience. Please scroll down to see the full text

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

    E-Print Network [OSTI]

    Liu, Hongyu

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

  11. NUMERICAL COUPLING OF ELECTRIC CIRCUIT EQUATIONS AND ENERGY-TRANSPORT MODELS FOR SEMICONDUCTORS

    E-Print Network [OSTI]

    Jngel, Ansgar

    NUMERICAL COUPLING OF ELECTRIC CIRCUIT EQUATIONS AND ENERGY-TRANSPORT MODELS FOR SEMICONDUCTORS effects is proposed. The charged particle flow in the semiconductor devices is described by the energy-transport equations for the electrons and the drift-diffusion equations for the holes. The electric circuit is modeled

  12. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout / Transforming Y-12Capacity-Forum Sign InTransportation

  13. A Quasi-Classical Model of Intermediate Velocity Particle Production in Asymmetric Heavy Ion Reactions

    E-Print Network [OSTI]

    A. Chernomoretz; L. Gingras; Y. Larochelle; L. Beaulieu; R. Roy; C. St-Pierre; C. O. Dorso

    2002-03-20

    The particle emission at intermediate velocities in mass asymmetric reactions is studied within the framework of classical molecular dynamics. Two reactions in the Fermi energy domain were modelized, $^{58}$Ni+C and $^{58}$Ni+Au at 34.5 MeV/nucleon. The availability of microscopic correlations at all times allowed a detailed study of the fragment formation process. Special attention was paid to the physical origin of fragments and emission timescales, which allowed us to disentangle the different processes involved in the mid-rapidity particle production. Consequently, a clear distinction between a prompt pre- equilibrium emission and a delayed aligned asymmetric breakup of the heavier partner of the reaction was achieved.

  14. Bottom-up model of adsorption and transport in multiscale porous media

    E-Print Network [OSTI]

    Ulm, Franz-Josef

    We develop a model of transport in multiscale porous media which accounts for adsorption in the different porosity scales. This model employs statistical mechanics to upscale molecular simulation and describe adsorption ...

  15. 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

    2013-01-01

    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.

  16. Modeling of On-Cell Reforming Reaction for Planar SOFC Stacks

    SciTech Connect (OSTI)

    Yang, Choongmo; Lim, Hyung-Tae; Hwang, Soon Cheol; Kim, Dohyung; Lai, Canhai; Koeppel, Brian J.; Recknagle, Kurtis P.; Khaleel, Mohammad A.

    2011-05-30

    Planar Solid Oxide Fuel Cell (SOFC) stack is known to suffer thermal problem from high stack temperature during operation to generate high current. On-Cell Reforming (OCR) phenomenon is often used to reduce stack temperature by an endothermic reaction of steam-methane reforming process. RIST conducted single-cell experiment to validate modeling tool to simulate OCR performance including temperature measurement. 2D modeling is used to check reforming rate during OCR using temperature measurement data, and 3D modeling is used to check overall thermal performance including furnace boundary conditions.

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

    SciTech Connect (OSTI)

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

    2010-11-05

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

  18. Model Annex for Preparedness and Response to Radiological Transportation Incidents

    Broader source: Energy.gov [DOE]

    This part should contain a general statement of the intent of this Annex. To provide for the planning, preparedness and coordination of emergency service efforts to respond to a transportation...

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

    E-Print Network [OSTI]

    Dr.V.Charles

    2007-03-07

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

  20. Human and modeling approaches for humanitarian transportation planning

    E-Print Network [OSTI]

    Gralla, Erica Lynn

    2012-01-01

    Recent disasters have highlighted the need for more effective supply chain management during emergency response. Planning and prioritizing the use of trucks and helicopters to transport humanitarian aid to affected communities ...

  1. Analytical modeling of contaminant transport and horizontal well hydraulics

    E-Print Network [OSTI]

    Park, Eungyu

    2004-09-30

    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...

  2. Nonlocal transport model in equilibrium two-component plasmas

    SciTech Connect (OSTI)

    Zheng Zhen; Rozmus, W. [Department of Physics, Theoretical Physics Institute, University of Alberta, Alberta, Edmonton T6G 2J1 (Canada); Bychenkov, V. Yu.; Brantov, A. V. [P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53, Moscow 119991 (Russian Federation); Capjack, C. E. [Department of Electrical and Computer Engineering, University of Alberta, Alberta, Edmonton T6G 2V4 (Canada)

    2009-10-15

    The full set of linearized Fokker-Planck kinetic equations with Landau collision terms have been solved as an initial-value problem for equilibrium electron-ion plasmas. This work is a generalization of the nonlocal transport theory by Bychenkov et al. [Phys. Rev. Lett. 75, 4405 (1995)] to both electron and ion components with frequency-dependent responses. Transport closure relations have been obtained for the complete set of electron and ion fluid equations which are valid over the full range of particle collisionality and for an arbitrary ionic charge. The well-known limits of collisionless and strongly collisional plasma transport theory have been recovered. Practical fits based on the numerical calculations have been introduced for nonlocal and frequency-dependent ion transport coefficients.

  3. Modeling of Transport in Lithium Ion Battery Electrodes

    E-Print Network [OSTI]

    Martin, Michael

    2012-07-16

    and time consuming prototypical experiments. Of the numerous processes occurring in these systems, solid state transport in particular has drawn a large amount of attention from the research community, as it tends to be one of the rate limiting steps...

  4. 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

    2011-11-02

    '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.

  5. 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

    2011-05-01

    '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.

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

    SciTech Connect (OSTI)

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

    2011-02-15

    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.

  7. Test of statistical model cross section calculations for $\\alpha$-induced reactions on $^{107}$Ag at energies of astrophysical interest

    E-Print Network [OSTI]

    Yalcin, C; Rauscher, T; Kiss, G G; zkan, N; Gray, R T; Halsz, Z; Szcs, T; Flp, Zs; Korkulu, Z; Somorjai, E

    2015-01-01

    Astrophysical reaction rates, which are mostly derived from theoretical cross sections, are necessary input to nuclear reaction network simulations for studying the origin of $p$ nuclei. Past experiments have found a considerable difference between theoretical and experimental cross sections in some cases, especially for ($\\alpha$,$\\gamma$) reactions at low energy. Therefore, it is important to experimentally test theoretical cross section predictions at low, astrophysically relevant energies. The aim is to measure reaction cross sections of $^{107}$Ag($\\alpha$,$\\gamma$)$^{111}$In and $^{107}$Ag($\\alpha$,n)$^{110}$In at low energies in order to extend the experimental database for astrophysical reactions involving $\\alpha$ particles towards lower mass numbers. Reaction rate predictions are very sensitive to the optical model parameters and this introduces a large uncertainty into theoretical rates involving $\\alpha$ particles at low energy. We have also used Hauser-Feshbach statistical model calculations to s...

  8. Nuclear Reaction Rate Uncertainties and Astrophysical Modeling. II. Carbon Yields from Low-mass Giants

    E-Print Network [OSTI]

    F. Herwig; Sam M. Austin; John C. Lattanzio

    2005-11-14

    Calculations that demonstrate the influence of three key nuclear reaction rates on the evolution of Asymptotic Giant Branch stars have been carried out. We study the case of a star with an initial mass of 2Msun and a metallicity of Z=0.01, somewhat less than the solar metallicity. The dredge-up of nuclear processed material from the interior of the star, and the yield predictions for carbon, are sensitive to the rate of the N14(p,gamma)O15 and triple-alpha reactions. These reactions dominate the H- and He-burning shells of stars in this late evolutionary phase. Published uncertainty estimates for each of these two rates propagated through stellar evolution calculations cause uncertainties in carbon enrichment and yield predictions of about a factor of two. The other important He-burning reaction C12(alpha,gamma)O16, although associated with the largest uncertainty in our study, does not have a significant influence on the abundance evolution compared to other modelling uncertainties. This finding remains valid when the entire evolution from the main-sequence to the tip of the AGB is considered. We discuss the experimental sources of the rate uncertainties addressed here, and give some outlook for future work.

  9. Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics

    E-Print Network [OSTI]

    Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics

  10. Comparison between JET Profile Data and the Predictions of a Transport Model Based on ITG and Trapped Electron Modes

    E-Print Network [OSTI]

    Comparison between JET Profile Data and the Predictions of a Transport Model Based on ITG and Trapped Electron Modes

  11. 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

    2008-09-01

    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.

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

    E-Print Network [OSTI]

    Huang, Su-Yun

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

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

    SciTech Connect (OSTI)

    Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J.

    2011-05-15

    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.

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

    E-Print Network [OSTI]

    Lummerzheim, Dirk

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

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

    E-Print Network [OSTI]

    Zhu, Chen

    2003-01-01

    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 pond in the western USA. Advectivedispersivereactive transport is simulated for a 5-year period

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

    E-Print Network [OSTI]

    ; revised 3 January 2005; accepted 21 January 2005; published 13 May 2005. [1] Bioremediation can be a cost-dimensional reactive transport modeling of carbon tetrachloride (CT) bioremediation at the Schoolcraft site in western transport and biodegradation at the Schoolcraft, Michigan, site, Water Resour. Res., 41, W05011, doi:10

  17. * 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

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

    E-Print Network [OSTI]

    Hassanizadeh, S. Majid

    of radioactive waste in geological formations, simulation of radionuclide transport by groundwater playsMathematical 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

  19. Estimate of recharge from radiocarbon dating of groundwater and numerical flow and transport modeling

    E-Print Network [OSTI]

    Zhu, Chen

    of radioactive waste repositories. A case study of a regional aquifer in northeastern Arizona shows the rechargeEstimate of recharge from radiocarbon dating of groundwater and numerical flow and transport ages using a linked numerical 14 C transport and flow model while hydraulic conductivity values

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

    E-Print Network [OSTI]

    Politcnica de Catalunya, Universitat

    Multicomponent reactive transport modeling at the Ratones uranium mine, Cceres (Spain) Modelacin 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 inundacin de minas

  1. Reaction selectivity studies on nanolithographically-fabricated platinum model catalyst arrays

    SciTech Connect (OSTI)

    Grunes, Jeffrey Benjamin

    2004-05-15

    In an effort to understand the molecular ingredients of catalytic activity and selectivity toward the end of tuning a catalyst for 100% selectivity, advanced nanolithography techniques were developed and utilized to fabricate well-ordered two-dimensional model catalyst arrays of metal nanostructures on an oxide support for the investigation of reaction selectivity. In-situ and ex-situ surface science techniques were coupled with catalytic reaction data to characterize the molecular structure of the catalyst systems and gain insight into hydrocarbon conversion in heterogeneous catalysis. Through systematic variation of catalyst parameters (size, spacing, structure, and oxide support) and catalytic reaction conditions (hydrocarbon chain length, temperature, pressures, and gas composition), the data presented in this dissertation demonstrate the ability to direct a reaction by rationally adjusting, through precise control, the design of the catalyst system. Electron beam lithography (EBL) was employed to create platinum nanoparticles on an alumina (Al{sub 2}O{sub 3}) support. The Pt nanoparticle spacing (100-150-nm interparticle distance) was varied in these samples, and they were characterized using x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), both before and after reactions. The TEM studies showed the 28-nm Pt nanoparticles with 100 and 150-nm interparticle spacing on alumina to be polycrystalline in nature, with crystalline sizes of 3-5 nm. The nanoparticle crystallites increased significantly after heat treatment. The nanoparticles were still mostly polycrystalline in nature, with 2-3 domains. The 28-nm Pt nanoparticles deposited on alumina were removed by the AFM tip in contact mode with a normal force of approximately 30 nN. After heat treatment at 500 C in vacuum for 3 hours, the AFM tip, even at 4000 nN, could not remove the platinum nanoparticles. The increase of adhesion upon heat treatment indicates stronger bonding between the Pt and the support at the metal-oxide interface.

  2. Complex Particle and Light Fragment Emission in the Cascade-Exciton Model of Nuclear Reactions

    E-Print Network [OSTI]

    Stepan G. Mashnik; Arnold J. Sierk; Konstantin K. Gudima

    2002-08-23

    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 4He) production, the CEM2k code has been merged with the GEM2 code of Furihata. We present some results on proton-induced fragmentation and fission reactions 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. We have initiated another approach to describe fission, complex particles and fragment emission by developing further our CEM2k code addressing specifically these problems. In this effort, we have developed our own universal approximation for inverse cross sections, new routines to calculate Coulomb barriers and widths of emitted particles and to simulate their kinetic energy using arbitrary approximations for the inverse cross sections. To describe fission-fragment production, we have incorporated into CEM2k a thermodynamical model of fission by Stepanov. This extended version of CEM2k allows us to describe much better complex particle emission and many fission fragments, but it is still incomplete and needs further work.

  3. Approaches to Modeling Coupled Flow and Reaction in a 2-D Cementation Experiment

    SciTech Connect (OSTI)

    Steefel, Carl; Cochepin, B.; Trotignon, L.; Bildstein, O.; Steefel, C.; Lagneau, V.; van der Lee, J.

    2008-04-01

    Porosity evolution at reactive interfaces is a key process that governs the evolution and performances of many engineered systems that have important applications in earth and environmental sciences. This is the case, for example, at the interface between cement structures and clays in deep geological nuclear waste disposals. Although in a different transport regime, similar questions arise for permeable reactive barriers used for biogeochemical remediation in surface environments. The COMEDIE project aims at investigating the coupling between transport, hydrodynamics and chemistry when significant variations of porosity occur. The present work focuses on a numerical benchmark used as a design exercise for the future COMEDIE-2D experiment. The use of reactive transport simulation tools like Hytec and Crunch provides predictions of the physico-chemical evolutions that are expected during the future experiments in laboratory. Focus is given in this paper on the evolution during the simulated experiment of precipitate, permeability and porosity fields. A first case is considered in which the porosity is constant. Results obtained with Crunch and Hytec are in relatively good agreement. Differences are attributable to the models of reactive surface area taken into account for dissolution/precipitation processes. Crunch and Hytec simulations taking into account porosity variations are then presented and compared. Results given by the two codes are in qualitative agreement, with differences attributable in part to the models of reactive surface area for dissolution/precipitation processes. As a consequence, the localization of secondary precipitates predicted by Crunch leads to lower local porosities than for predictions obtained by Hytec and thus to a stronger coupling between flow and chemistry. This benchmark highlights the importance of the surface area model employed to describe systems in which strong porosity variations occur as a result of dissolution/precipitation. The simulation of highly non-linear reactive transport systems is also shown to be partly dependent on specific numerical approaches.

  4. Model Proton-Coupled Electron Transfer Reactions in Solution: Predictions of Rates, Mechanisms, and Kinetic Isotope Effects

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Model Proton-Coupled Electron Transfer Reactions in Solution: Predictions of Rates, Mechanisms isotope effects for proton-coupled electron transfer (PCET) reactions. These studies are based, the solvent is represented as a dielectric continuum, and the active electrons and transferring protons

  5. Convergence in the QM-Only and QM/MM Modeling of Enzymatic Reactions: A Case Study for Acetylene

    E-Print Network [OSTI]

    Liao, Rongzhen

    Convergence in the QM-Only and QM/MM Modeling of Enzymatic Reactions: A Case Study for Acetylene/molecular mechanics (MM) calculations on an enzyme- catalyzed reaction to assess the convergence behavior of QM- only and QM/MM energies with respect to the size of the cho- sen QM region. The QM and MM parts are described

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

    E-Print Network [OSTI]

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

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

    E-Print Network [OSTI]

    Zheng, Chunmiao

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

  8. A new model for the transport of particles in a thermostatted system

    E-Print Network [OSTI]

    Rondoni, Lamberto

    ]). The purpose is to understand transport phenomena on the basis of the microscopic dynamics and, in partic- ular particles) are of course less realistic than interacting particle systems. They are indeed good models

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

    E-Print Network [OSTI]

    Link, Percy Anne

    2008-01-01

    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, ...

  10. Confocal Image-Based Computational Modeling of Nitric Oxide Transport in a Rat Mesenteric Lymphatic Vessel

    E-Print Network [OSTI]

    Wilson, John 1988-

    2012-11-15

    physiologic geometries obtained from confocal images of a rat mesenteric lymphatic vessel to determine the characteristics of NO transport in the lymphatic flow regime. Both steady and unsteady analyses were performed. Steady models were simulated...

  11. Tearing-mode transport model in the reversed field pinch concept

    E-Print Network [OSTI]

    Bruno, Antonio, 1972-

    2002-01-01

    In this thesis, a self-consistent model for analyzing the transport performance of a Reversed Field Pinch (RFP)-type of thermonuclear fusion reactor has been developed. The study has been focused on determining equilibrium ...

  12. 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.

    2002-01-01

    Using a multiphase transport model, we study J/psi production from interactions between charm and anticharm quarks in the initial parton phase and between D and (D) over bar mesons in the final hadron phase of relativistic ...

  13. Extended three-dimensional ADCIRC hydrodynamic model to include baroclinic flow and sediment transport

    E-Print Network [OSTI]

    Pandoe, Wahyu Widodo

    2004-09-30

    provides a basis for determining how the water circulation three-dimensionally controls the hydrodynamics of the system and ultimately transports the suspended and soluble materials due to combined currents and waves. A three-dimensional circulation model...

  14. FLOW AND REACTIVE TRANSPORT MODELING IN THE GTS-HPF EXPERIMENT

    E-Print Network [OSTI]

    Politcnica de Catalunya, Universitat

    repositories for L/IL radioactive waste Hyperalkaline solutions #12;GTS-HPF Grimsel Test Site - HyperalkalineFLOW AND REACTIVE TRANSPORT MODELING IN THE GTS-HPF EXPERIMENT Grimsel Test Site Hyperalkaline

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

    E-Print Network [OSTI]

    Hoefel, Fernanda Gemael, 1973-

    2004-01-01

    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 ...

  16. P. Douillet S. Ouillon E. Cordier A numerical model for ne suspended sediment transport

    E-Print Network [OSTI]

    transport Numerical model Deposition Erosion New Caledonia Introduction In New Caledonia, where open-cast for cohesive particles (e.g., Nicholson and O'Connor 1986; Teisson 1991; Brenon and Le Hir 1999), around sand

  17. 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 ...

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

    SciTech Connect (OSTI)

    1996-12-01

    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.

  19. MODELING USER TRANSPORTATION PATTERNS USING MOBILE DEVICES ERFAN DAVAMI

    E-Print Network [OSTI]

    Sukthankar, Gita Reese

    a smartphone. Increased cover- age and higher speeds of cellular networks have given these devices the power, cameras, and microphones. This expansion of smartphone numbers and power has created a sensing system from cell-phone and social media check-ins. To study large-scale transportation patterns, I created

  20. 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

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

    E-Print Network [OSTI]

    Sim, Youn

    1992-01-01

    APPLICATION OF MULTIDIMENSIONAL ANALYTICAL TRANSPORT MODELS TO COAL-TAR DERIVATIVES A Thesis by YOUN SIM 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: Geology APPLICATION OF MULTIDIMENSIONAL ANALYTICAL TRANSPORT MODELS TO COAL-TAR DERIVATIVES A Thesis by YOUN SIM Approved as to style and content by: Patrick A. Domenico (Chair of Committee) N man...

  2. 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

  3. Measure of Diffusion Model Error for Thermal Radiation Transport

    E-Print Network [OSTI]

    Kumar, Akansha

    2013-04-19

    and computational time. However, this approximation often has significant error. Error due to the inherent nature of a physics model is called model error. Information about the model error associated with the diffusion approximation is clearly desirable...

  4. 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-

    2007-01-01

    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 ...

  5. Effects of the equilibrium model on impurity transport in tokamaks

    E-Print Network [OSTI]

    Skyman, Andreas; Tegnered, Daniel; Nordman, Hans; Anderson, Johan; Strand, Pr

    2014-01-01

    Gyrokinetic simulations of ion temperature gradient mode and trapped electron mode driven impurity transport in a realistic tokamak geometry are presented and compared with results using simplified geometries. The gyrokinetic results, obtained with the GENE code in both linear and non-linear modes are compared with data and analysis for a dedicated impurity injection discharge at JET. The impact of several factors on heat and particle transport is discussed, lending special focus to tokamak geometry and rotational shear. To this end, results using s-alpha and concentric circular equilibria are compared with results with magnetic geometry from a JET experiment. To further approach experimental conditions, non-linear gyrokinetic simulations are performed with collisions and a carbon background included. The impurity peaking factors, computed by finding local density gradients corresponding to zero particle flux, are discussed. The impurity peaking factors are seen to be reduced by a factor of ~2 in realistic ge...

  6. Study of DCX reaction on medium nuclei with Monte-Carlo Shell Model

    SciTech Connect (OSTI)

    Wu, H. C.; Gibbs, W. R.

    2010-08-04

    In this work a method is introduced to calculate the DCX reaction in the framework of Monte-Carlo Shell Model (MCSM). To facilitate the use of Zero-temperature formalism of MCSM, the Double-Isobaric-Analog State (DIAS) is derived from the ground state by using isospin shifting operator. The validity of this method is tested by comparing the MCSM results to those of the SU(3) symmetry case. Application of this method to DCX on {sup 56}Fe and {sup 93}Nb is discussed.

  7. 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)

    2013-02-15

    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.

  8. Coupled modeling of grounddwater flow solute transport, chemical reactions and microbial processes in the "SP" island

    E-Print Network [OSTI]

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

    2003-01-01

    Geochemistry, 14, 893905. Pourbaix M, 1945. Ph.D. Thesis.Hogeschool Delft. The Netherlands Pourbaix M, Zubov N, 1963.d'Equilibres Electrochimiques (Pourbaix, M. Ed. ). Gauthier-

  9. A gyro-Landau-fluid transport model R. E. Waltz, G. M. Staebler, W. Dorland,a)

    E-Print Network [OSTI]

    Hammett, Greg

    A gyro-Landau-fluid transport model R. E. Waltz, G. M. Staebler, W. Dorland,a) G. W. Hammett,b) M 7 February 1997; accepted 3 April 1997 A physically comprehensive and theoretically based transport transport profile database with good agreement. This model is capable of describing enhanced core

  10. Mass-transport models to predict toxicity of inhaled gases in the upper respiratory tract

    SciTech Connect (OSTI)

    Hubal, E.A.C.; Fedkiw, P.S.; Kimbell, J.S. [North Carolina State Univ., Raleigh, NC (United States)

    1996-04-01

    Mass-transport (the movement of a chemical species) plays an important role in determining toxic responses of the upper respiratory tract (URT) to inhaled chemicals. Mathematical dosimetry models incorporate physical characteristics of mass transport and are used to predict quantitative uptake (absorption rate) and distribution of inhaled gases and vapors in the respiratory tract. Because knowledge of dose is an essential component of quantitative risk assessment, dosimetry modeling plays an important role in extrapolation of animal study results to humans. A survey of existing mathematical dosimetry models for the URT is presented, limitations of current models are discussed, and adaptations of existing models to produce a generally applicable model are suggested. Reviewed URT dosimetry models are categorized as early, lumped-parameter, and distributed-parameter models. Specific examples of other relevant modeling work are also presented. 35 refs., 11 figs., 1 tab.

  11. Test of statistical model cross section calculations for $?$-induced reactions on $^{107}$Ag at energies of astrophysical interest

    E-Print Network [OSTI]

    C. Yalcin; Gy. Gyrky; T. Rauscher; G. G. Kiss; N. zkan; R. T. Gray; Z. Halsz; T. Szcs; Zs. Flp; Z. Korkulu; E. Somorjai

    2015-04-07

    Astrophysical reaction rates, which are mostly derived from theoretical cross sections, are necessary input to nuclear reaction network simulations for studying the origin of $p$ nuclei. Past experiments have found a considerable difference between theoretical and experimental cross sections in some cases, especially for ($\\alpha$,$\\gamma$) reactions at low energy. Therefore, it is important to experimentally test theoretical cross section predictions at low, astrophysically relevant energies. The aim is to measure reaction cross sections of $^{107}$Ag($\\alpha$,$\\gamma$)$^{111}$In and $^{107}$Ag($\\alpha$,n)$^{110}$In at low energies in order to extend the experimental database for astrophysical reactions involving $\\alpha$ particles towards lower mass numbers. Reaction rate predictions are very sensitive to the optical model parameters and this introduces a large uncertainty into theoretical rates involving $\\alpha$ particles at low energy. We have also used Hauser-Feshbach statistical model calculations to study the origin of possible discrepancies between prediction and data. An activation technique has been used to measure the reaction cross sections at effective center of mass energies between 7.79 MeV and 12.50 MeV. Isomeric and ground state cross sections of the ($\\alpha$,n) reaction were determined separately. The measured cross sections were found to be lower than theoretical predictions for the ($\\alpha$,$\\gamma$) reaction. Varying the calculated averaged widths in the Hauser-Feshbach model, it became evident that the data for the ($\\alpha$,$\\gamma$) and ($\\alpha$,n) reactions can only be simultaneously reproduced when rescaling the ratio of $\\gamma$- to neutron width and using an energy-dependent imaginary part in the optical $\\alpha$+$^{107}$Ag potential.......

  12. Analytical modelling of hydrogen transport in reactor containments

    E-Print Network [OSTI]

    Manno, V.

    1983-01-01

    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 ...

  13. Modeling of the electronic transport in multijunction solar cells

    SciTech Connect (OSTI)

    Rau, U.; Goldbach, M.

    1994-12-31

    Simulations of the electrical transport in multijunction thin-film solar cells made from polycrystalline silicon are presented. The authors investigate the effect of the grain size on the efficiency of the multijunction solar cell. Here, they concentrate on micro crystalline material with a high recombination velocity at the grain boundaries of 10{sup 4}cm/s. Typical results of their calculations demonstrate that based on the multijunction design structure consisting of 8 or more layers efficiencies of 14% may be obtained from 12--20 {micro}m thick solar cells.

  14. 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)

    2015-01-01

    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.

  15. Realistic multisite lattice-gas modeling and KMC simulation of catalytic surface reactions: Kinetics and multiscale spatial behavior for CO-oxidation on metal (100) surfaces

    SciTech Connect (OSTI)

    Liu, Dajiang [Ames Laboratory; Evans, James W. [Ames Laboratory

    2013-12-01

    A realistic molecular-level description of catalytic reactions on single-crystal metal surfaces can be provided by stochastic multisite lattice-gas (msLG) models. This approach has general applicability, although in this report, we will focus on the example of CO-oxidation on the unreconstructed fcc metal (100) or M(100) surfaces of common catalyst metals M = Pd, Rh, Pt and Ir (i.e., avoiding regimes where Pt and Ir reconstruct). These models can capture the thermodynamics and kinetics of adsorbed layers for the individual reactants species, such as CO/M(100) and O/M(100), as well as the interaction and reaction between different reactant species in mixed adlayers, such as (CO + O)/M(100). The msLG models allow population of any of hollow, bridge, and top sites. This enables a more flexible and realistic description of adsorption and adlayer ordering, as well as of reaction configurations and configuration-dependent barriers. Adspecies adsorption and interaction energies, as well as barriers for various processes, constitute key model input. The choice of these energies is guided by experimental observations, as well as by extensive Density Functional Theory analysis. Model behavior is assessed via Kinetic Monte Carlo (KMC) simulation. We also address the simulation challenges and theoretical ramifications associated with very rapid diffusion and local equilibration of reactant adspecies such as CO. These msLG models are applied to describe adsorption, ordering, and temperature programmed desorption (TPD) for individual CO/M(100) and O/M(100) reactant adlayers. In addition, they are also applied to predict mixed (CO + O)/M(100) adlayer structure on the nanoscale, the complete bifurcation diagram for reactive steady-states under continuous flow conditions, temperature programmed reaction (TPR) spectra, and titration reactions for the CO-oxidation reaction. Extensive and reasonably successful comparison of model predictions is made with experimental data. Furthermore, we discuss the possible transition from traditional mean-field-type bistability and reaction kinetics for lower-pressure to multistability and enhanced fluctuation effects for moderate- or higher-pressure. Behavior in the latter regime reflects a stronger influence of adspecies interactions and also lower diffusivity in the higher-coverage mixed adlayer. We also analyze mesoscale spatiotemporal behavior including the propagation of reaction diffusion fronts between bistable reactive and inactive states, and associated nucleation-mediated transitions between these states. This behavior is controlled by complex surface mass transport processes, specifically chemical diffusion in mixed reactant adlayers for which we provide a precise theoretical formulation. The msLG models together with an appropriate treatment of chemical diffusivity enable equation-free heterogeneous coupled lattice-gas (HCLG) simulations of spatiotemporal behavior. In addition, msLG + HCLG modeling can describe coverage variations across polycrystalline catalysts surfaces, pressure variations across catalyst surfaces in microreactors, and could be incorporated into a multiphysics framework to describe mass and heat transfer limitations for high-pressure catalysis. (C) 2013 Elsevier Ltd. All rights reserved.

  16. 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.

    1992-05-01

    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.

  17. 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.

    1992-01-01

    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.

  18. 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

    2013-09-01

    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.

  19. Preliminary characterization of materials for a reactive transport model validation experiment

    SciTech Connect (OSTI)

    Siegel, M.D.; Ward, D.B.; Cheng, W.C.; Bryant, C.; Chocas, C.S.; Reynolds, C.G.

    1993-03-01

    The geochemical properties of a porous sand and several tracers (Ni, Br, and Li) have been characterized for use in a caisson experiment designed to validate sorption models used in models of inactive transport. The surfaces of the sand grains have been examined by a combination of techniques including potentiometric titration, acid leaching, optical microscopy, and scanning electron microscopy with energy-dispersive spectroscopy. The surface studies indicate the presence of small amounts of carbonate, kaolinite and iron-oxyhydroxides. Adsorption of nickel, lithium and bromide by the sand was measured using batch techniques. Bromide was not sorbed by the sand. A linear (K{sub d}) or an isotherm sorption model may adequately describe transport of Li; however, a model describing the changes of pH and the concentrations of other solution species as a function of time and position within the caisson and the concomitant effects on Ni sorption may be required for accurate predictions of nickel transport.

  20. 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

    2005-04-01

    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.

  1. 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 is devoted to the numerical simulation of a linearized model for the lubricated trans- portation of heavy acts as a lubricant by coating the wall of the pipeline, thus preventing the oil from adhering

  2. Modelling the transport of lobster (Homarus americanus) larvae and postlarvae in the Gulf of Maine

    E-Print Network [OSTI]

    Modelling the transport of lobster (Homarus americanus) larvae and postlarvae in the Gulf of Maine and settlement locations for lobsters in the Gulf of Maine. The physical model is based on a nite-element mesh by mid-season at most sites, but strong spatial differences persisted. The eastern Maine coast appears

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

    E-Print Network [OSTI]

    Buldyrev, Sergey

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

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

    E-Print Network [OSTI]

    Holmes, Christopher D.

    by atomic bromine (Br) in the tropo- sphere by combining kinetic data for the Hg-Br system with modeledMultiscale models of atmospheric mercury: bromine chemistry, air-sea exchange, and global transport rights reserved. #12;iii Dissertation Advisor Author Professor Daniel J. Jacob Christopher D. Holmes

  5. Grand challenge problems in environmental modeling and remediation: groundwater contaminant transport

    SciTech Connect (OSTI)

    Todd Arbogast; Steve Bryant; Clint N. Dawson; Mary F. Wheeler

    1998-08-31

    This report describes briefly the work of the Center for Subsurface Modeling (CSM) of the University of Texas at Austin (and Rice University prior to September 1995) on the Partnership in Computational Sciences Consortium (PICS) project entitled Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport.

  6. On the emissions and transport of bromoform: sensitivity to model resolution and emission location

    E-Print Network [OSTI]

    Russo, M. R.; Ashfold, M. J.; Harris, N. R. P.; Pyle, J. A.

    2015-07-31

    stratospheric ozone budget. In a modelling study, we investigate the importance of the regional distribution of the emissions and of model resolution for the transport of bromoform to the TTL. We use two idealised CHBr3 emission fields (one coastal, one...

  7. Centrifuge modeling of LNAPL transport in partially saturated sand

    SciTech Connect (OSTI)

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

    1999-12-01

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

  8. Temperature, humidity and air flow in the emplacement drifts using convection and dispersion transport models

    SciTech Connect (OSTI)

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

    2009-10-01

    A coupled thermal-hydrologic-airflow model is developed, solving for the transport processes within a waste emplacement drift and the surrounding rockmass together at the proposed nuclear waste repository at Yucca Mountain. Natural, convective air flow as well as heat and mass transport in a representative emplacement drift during post-closure are explicitly simulated, using the MULTIFLUX model. The conjugate, thermal-hydrologic transport processes in the rockmass are solved with the TOUGH2 porous-media simulator in a coupled way to the in-drift processes. The new simulation results show that large-eddy turbulent flow, as opposed to small-eddy flow, dominate the drift air space for at least 5000 years following waste emplacement. The size of the largest, longitudinal eddy is equal to half of the drift length, providing a strong axial heat and moisture transport mechanism from the hot to the cold drift sections. The in-drift results are compared to those from simplified models using a surrogate, dispersive model with an equivalent dispersion coefficient for heat and moisture transport. Results from the explicit, convective velocity simulation model provide higher axial heat and moisture fluxes than those estimated from the previously published, simpler, equivalent-dispersion models, in addition to showing differences in temperature, humidity and condensation rate distributions along the drift length. A new dispersive model is also formulated, giving a time- and location-variable function that runs generally about ten times higher in value than the highest dispersion coefficient currently used in the Yucca Mountain Project as an estimate for the equivalent dispersion coefficient in the emplacement drift. The new dispersion coefficient variation, back-calculated from the convective model, can adequately describe the heat and mass transport processes in the emplacement drift example.

  9. Baseline requirements of the proposed action for the Transportation Management Division routing models

    SciTech Connect (OSTI)

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

    1995-02-01

    The potential impacts associated with the transportation of hazardous materials are important to shippers, carriers, and the general public. This is particularly true for shipments of radioactive material. The shippers are primarily concerned with safety, security, efficiency, and equipment requirements. The carriers are concerned with the potential impact that radioactive shipments may have on their operations--particularly if such materials are involved in an accident. The general public has also expressed concerns regarding the safety of transporting radioactive and other hazardous materials through their communities. Because transportation routes are a central concern in hazardous material transport, the prediction of likely routes is the first step toward resolution of these issues. In response to these routing needs, several models have been developed over the past fifteen years at Oak Ridge National Laboratory (ORNL). The HIGHWAY routing model is used to predict routes for truck transportation, the INTERLINE routing model is used to predict both rail and barge routes, and the AIRPORT locator model is used to determine airports with specified criteria near a specific location. As part of the ongoing improvement of the US Department of Energy`s (DOE) Environmental Management Transportation Management Division`s (EM-261) computer systems and development efforts, a Baseline Requirements Assessment Session on the HIGHWAY, INTERLINE, and AIRPORT models was held at ORNL on April 27, 1994. The purpose of this meeting was to discuss the existing capabilities of the models and data bases and to review enhancements of the models and data bases to expand their usefulness. The results of the Baseline Requirements Assessment Section will be discussed in this report. The discussions pertaining to the different models are contained in separate sections.

  10. MATHEMATICAL MODELS OF THERMAL AND CHEMICAL TRANSPORT IN GEOLOGIC MEDIA

    E-Print Network [OSTI]

    Lai, C.-H.

    2010-01-01

    in Hot Dry Rock Geothermal Systems, LA-9404-T, Los AlamosModeling of Geothermal Systems . . . . . . . . . . .the evolution of geothermal systems during exploitation.

  11. Chemistry of Furan Conversion into Aromatics and Olefins over HZSM-5: A Model Biomass Conversion Reaction

    SciTech Connect (OSTI)

    Cheng, Yu-Ting; Huber, George W.

    2011-06-03

    The conversion of furan (a model of cellulosic biomass) over HZSM-5 was investigated in a thermogravimetric analysismass spectrometry system, in situ Fourier transform infrared analysis, and in a continuous-flow fixed-bed reactor. Furan adsorbed as oligomers at room temperature with a 1.73 of adsorbed furan/Al ratio. These oligomers were polycyclic aromatic compounds that were converted to CO, CO?, aromatics, and olefins at temperatures from 400 to 600 C. Aromatics (e.g., benzene, toluene, and naphthalene), oligomer isomers (e.g., benzofuran, 2,2-methylenebisfuran, and benzodioxane), and heavy oxygenates (C??{sub +} oligomers) were identified as intermediates formed inside HZSM-5 at different reaction temperatures. During furan conversion, graphite-type coke formed on the catalyst surface, which caused the aromatics and olefins formation to deactivate within the first 30 min of time on-stream. We have measured the effects of space velocity and temperature for furan conversion to help us understand the chemistry of biomass conversion inside zeolite catalysts. The major products for furan conversion included CO, CO?, allene, C?C? olefins, benzene, toluene, styrene, benzofuran, indene, and naphthalene. The aromatics (benzene and toluene) and olefins (ethylene and propylene) selectivity decreased with increasing space velocity. Unsaturated hydrocarbons such as allene, cyclopentadiene, and aromatics selectivity increased with increasing space velocity. The product distribution was selective to olefins and CO at high temperatures (650 C) but was selective to aromatics (benzene and toluene) at intermediate temperatures (450600 C). At low temperatures (450 C), benzofuran and coke contributed 60% of the carbon selectivity. Several different reactions were occurring for furan conversion over zeolites. Some important reactions that we have identified in this study include DielsAlder condensation (e.g., two furans form benzofuran and water), decarbonylation (e.g., furan forms CO and allene), oligomerization (allene forms olefins and aromatics plus hydrogen), and alkylation (e.g., furan plus olefins). The product distribution was far from thermodynamic equilibrium.

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

    E-Print Network [OSTI]

    Wenjun Kou; Amneet Pal Singh Bhalla; Boyce E. Griffith; John E. Pandolfino; Peter J. Kahrilas; Neelesh A. Patankar

    2015-01-09

    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 into an integrated model. Consistent with experimental observations, our simulations capture the pressure peak generated by the muscle activation pulse that travels along the bolus tail. These fully resolved simulations provide new insights into roles of the mucosal layers during bolus transport. In addition, the information on pressure and the kinematics of the esophageal wall due to the coordination of muscle activation is provided, which may help relate clinical data from manometry and ultrasound images to the underlying esophageal motor function.

  13. 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)

    1997-08-01

    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.

  14. Collisional particle-in-cell modeling for energy transport accompanied by atomic processes in dense plasmas

    SciTech Connect (OSTI)

    Mishra, R.; Beg, F. N.; Leblanc, P.; Sentoku, Y.; Wei, M. S.

    2013-07-15

    Fully relativistic collisional Particle-in-Cell (PIC) code, PICLS, has been developed to study extreme energy density conditions produced in intense laser-solid interaction. Recent extensions to PICLS, such as the implementation of dynamic ionization, binary collisions in a partially ionized plasma, and radiative losses, enhance the efficacy of simulating intense laser plasma interaction and subsequent energy transport in resistive media. Different ionization models are introduced and benchmarked against each other to check the suitability of the model. The atomic physics models are critical to determine the energy deposition and transport in dense plasmas, especially when they consist of high Z (atomic number) materials. Finally we demonstrate the electron transport simulations to show the importance of target material on fast electron dynamics.

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

    SciTech Connect (OSTI)

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

    2014-11-01

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

  16. Proppant transport in hydraulic fracturing: Crack tip screen-out in KGD and P3D models

    E-Print Network [OSTI]

    Peirce, Anthony

    Proppant transport in hydraulic fracturing: Crack tip screen-out in KGD and P3D models E.V. Dontsov February 2015 Available online 14 March 2015 Keywords: Hydraulic fracturing Proppant transport Numerical, the equations that govern the propagation of hydraulic fractures and the proppant transport inside them

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

    E-Print Network [OSTI]

    McKenzie, Jeffrey M.

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

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

    E-Print Network [OSTI]

    Gnanadesikan, Anand

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

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

    E-Print Network [OSTI]

    Sudipto Muhuri; Ignacio Pagonabarraga

    2010-09-09

    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.

  20. Kinetics of the Reactions of Isoprene-Derived Epoxides in Model

    E-Print Network [OSTI]

    Elrod, Matthew J.

    for isoprene- and 1,3-butadiene- derived epoxides in order to determine the rates for such reactions

  1. Canadian Coastal Conference 1999 Conference Canadian sur la littoral 1999 SUSPENDED SEDlMENT TRANSPORT MODELING IN LAKE MICHIGAN

    E-Print Network [OSTI]

    sediment transport processes. The model was coupled with a 3-D circulation model and a wind wave model and nearshore-offshore transport in Lake Michigan are investigated. INTRODUCTION The presence of contaminated, a multidisplinary research program jointly sponsored by NOAA (National Oceanic and Atmospheric Administration

  2. Preface: Nonclassical Transport

    E-Print Network [OSTI]

    Bolshov, L.

    2010-01-01

    models of solute transport in highly heterogeneous geologicSemenov. 2008b. Nonclassical transport processes in geologicand L. Matveev. 2008. Transport regimes and concentration

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

    SciTech Connect (OSTI)

    P. Tucci

    2001-12-20

    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.

  4. Transportation Sector Module of the National Energy Modeling System

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home PageMonthly","10/2015"4,"Ames5 Tables July 1996 Energy Information Administration Office of Coal,Demand Module of the National Energy Modeling System: Model

  5. Modelling Prospects for Hydrogen-powered Transportation Until 2100

    E-Print Network [OSTI]

    for this work provided by the MIT Joint Program on the Science and Policy of Global Change through a consortium, especially the US Department of Energy, Integrated Assessment Program in the Office of Biological to the current gasoline-powered fleet. Using a computable general equilibrium model of the world economy, we

  6. Transport in the random Kronig-Penney model

    E-Print Network [OSTI]

    Maxim Drabkin; Werner Kirsch; Hermann Schulz-Baldes

    2012-07-02

    The Kronig-Penney model with random Dirac potentials on the lattice $\\ZM$ has critical energies at which the Lyapunov exponent vanishes and the density of states has a van Hove singularity. This leads to a non-trivial quantum diffusion even though the spectrum is known to be pure-point.

  7. Simulation model for oil slick transport in lakes

    SciTech Connect (OSTI)

    Shen, H.T.; Yapa, P.D.; Petroski, M.E.

    1987-10-01

    A computer model for simulating oil slick movement in lakes by a Lagrangian discrete parcel algorithm is presented. In this model the transformation of an oil slick due to advection, spreading, evaporation, and dissolution is considered. For open water conditions the movement of the oil slick by water current and wind is considered using the drifting factor formulation. For ice-covered conditions the drift velocity is determined according to the ice roughness and current velocity. The current distribution in the lake is determined by a rigid lid circulation model. In the spreading process the mechanical spreading of the oil slick due to the balance in inertia, gravity, viscous, and surface tension forces is considered, in addition to the dispersion of the surface oil layer. Boundary conditions along the shore are formulated according to the storage capacity of the shoreline. The model can be used for simulating either instantaneous or continuous oil spills. Sample simulations for oil spills in Lake St. Clair are presented.

  8. ESTIMATING RETARDATION FROM THE FREUNDLICH ISOTHERM FOR MODELING CONTAMINANT TRANSPORT

    E-Print Network [OSTI]

    Coles, Cynthia

    to model leachate migration from landfills is needed to protect the public and the environment. Introduction A concern with landfills, and especially older unlined landfills, is the migration of leachate risk of off-site leachate migration at newer, lined landfills with leachate collection systems

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

    SciTech Connect (OSTI)

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

    2014-11-24

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

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCEDInstallers/ContractorsPhotovoltaicsState ofSavingsTransmission SEABTransmittalLetter.pdfModeling

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

    E-Print Network [OSTI]

    Anthony B. Davis; Feng Xu

    2014-10-29

    We formulate a new model for transport in stochastic media with long-range spatial correlations where exponential attenuation (controlling the propagation part of the transport) becomes power law. Direct transmission over optical distance $\\tau(s)$, for fixed physical distance $s$, thus becomes $(1+\\tau(s)/a)^{-a}$, with standard exponential decay recovered when $a\\to\\infty$. Atmospheric turbulence phenomenology for fluctuating optical properties rationalizes this switch. Foundational equations for this generalized transport model are stated in integral form for $d=1,2,3$ spatial dimensions. A deterministic numerical solution is developed in $d=1$ using Markov Chain formalism, verified with Monte Carlo, and used to investigate internal radiation fields. Standard two-stream theory, where diffusion is exact, is recovered when $a=\\infty$. Differential diffusion equations are not presently known when $adetection, the other in a transition from one position to another in the medium.

  12. NREL: Transportation Research - Vehicle Thermal Management Models and Tools

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines lightGeospatial ToolkitSMARTSWorkingManagement Models and Tools image of

  13. EXTENSION OF THE NUCLEAR REACTION MODEL CODE EMPIRE TO ACTINIDES NUCLEAR DATA EVALUATION.

    SciTech Connect (OSTI)

    CAPOTE,R.; SIN, M.; TRKOV, A.; HERMAN, M.; CARLSON, B.V.; OBLOZINSKY, P.

    2007-04-22

    Recent extensions and improvements of the EMPIRE code system are outlined. They add new capabilities to the code, such as prompt fission neutron spectra calculations using Hauser-Feshbach plus pre-equilibrium pre-fission spectra, cross section covariance matrix calculations by Monte Carlo method, fitting of optical model parameters, extended set of optical model potentials including new dispersive coupled channel potentials, parity-dependent level densities and transmission through numerically defined fission barriers. These features, along with improved and validated ENDF formatting, exclusive/inclusive spectra, and recoils make the current EMPIRE release a complete and well validated tool for evaluation of nuclear data at incident energies above the resonance region. The current EMPIRE release has been used in evaluations of neutron induced reaction files for {sup 232}Th and {sup 231,233}Pa nuclei in the fast neutron region at IAEA. Triple-humped fission barriers and exclusive pre-fission neutron spectra were considered for the fission data evaluation. Total, fission, capture and neutron emission cross section, average resonance parameters and angular distributions of neutron scattering are in excellent agreement with the available experimental data.

  14. Modeling Bed-Load Transport of Coarse Sediments in the Great Bay Estuary, New Hampshire.

    E-Print Network [OSTI]

    Modeling Bed-Load Transport of Coarse Sediments in the Great Bay Estuary, New Hampshire. A. Bilgili Hanover, NH 03755, U.S.A. 2 University of New Hampshire Ocean and Mechanical Engineering Departments River section of the Great Bay Estuary, New Hampshire, USA.- a well-mixed and geometrically complex

  15. Modeling dust emissions and transport within Europe: The Ukraine March 2007 event

    E-Print Network [OSTI]

    Menut, Laurent

    Modeling dust emissions and transport within Europe: The Ukraine March 2007 event Bertrand originating from Ukraine related to chernozemic-erodible lands. Using surface and satellite measurements in the Netherlands, Belgium, and the north of France were mostly due to the extremely rare Ukraine dust event

  16. 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

  17. MT3DMS, A Modular Three-Dimensional Multispecies Transport Model User Guide to the

    E-Print Network [OSTI]

    Zheng, Chunmiao

    .M. Cozzarelli, M.H. Lahvis, and B.A. Bekins. 1998. Ground water contamination by crude oil near Bemidji (LNAPL) contaminant through the unsaturated zone and the formation of an oil lens on the water tableMT3DMS, A Modular Three-Dimensional Multispecies Transport Model User Guide to the Hydrocarbon

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

    E-Print Network [OSTI]

    Rattling and freezing in a 1-D transport model Jean-Pierre Eckmann1 and Lai-Sang Young2 1 D energy and fluxes as functions of (and time) . . . . . . . . . . . 14 4 Freezing 16 4.1 Distribution . . . . . . . . . . . . . . . . . . . . . . 18 4.2 Why this system freezes: a theoretical discussion . . . . . . . . . . . . . 18 4.3 Numerical

  19. A faster numerical scheme for a coupled system modelling soil erosion and sediment transport

    E-Print Network [OSTI]

    d'Orléans, Université

    A faster numerical scheme for a coupled system modelling soil erosion and sediment transport M flow and the bed sediment, are classically described by a well-established system coupling the shallow states and the positivity of both water depth and sediment concentration. Recently, finite volume schemes

  20. Freshwater Discharge, Sediment Transport, and Modeled Climate Impacts of the Final Drainage of Glacial Lake Agassiz

    E-Print Network [OSTI]

    Bush, John W.M.

    Freshwater Discharge, Sediment Transport, and Modeled Climate Impacts of the Final Drainage, whereas the postflood outflow through Hudson Strait had a lower load of suspended sediment and was buoyant hemispheric extent. This claim was bolstered by analyses of marine sediments in the tropical and North

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

    E-Print Network [OSTI]

    Hanke-Bourgeois, Martin

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

  2. TWO SPINORIAL DRIFT-DIFFUSION MODELS FOR QUANTUM ELECTRON TRANSPORT IN GRAPHENE

    E-Print Network [OSTI]

    Jngel, Ansgar

    . Introduction Graphene is a new semiconductor material, which is a subject of great interest for nanoscale [3]. Physically, graphene is a two-dimensional semiconductor with a zero-width band gap, consistingTWO SPINORIAL DRIFT-DIFFUSION MODELS FOR QUANTUM ELECTRON TRANSPORT IN GRAPHENE NICOLA ZAMPONI

  3. Model to Predict Temperature and Capillary Pressure Driven Water Transport in PEFCs After Shutdown

    E-Print Network [OSTI]

    Mench, Matthew M.

    Model to Predict Temperature and Capillary Pressure Driven Water Transport in PEFCs After Shutdown-912 Korea To enhance durability and cold-start performance of polymer electrolyte fuel cells PEFCs in the PEFC components after shutdown, which for the first time includes thermo-osmotic flow in the membrane

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

    SciTech Connect (OSTI)

    Reeves, Mark; Cranwell, Robert M.

    1981-11-01

    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.

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

    E-Print Network [OSTI]

    J. C. Misra; S. Maiti

    2011-12-28

    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.

  6. Molecular Modelling of Adsorption and Transport in Nanoporous Carbons: From the Simple Slit Pore Model to Virtual Porous Carbons

    E-Print Network [OSTI]

    Adler, Joan

    Molecular Modelling of Adsorption and Transport in Nanoporous Carbons: From the Simple Slit Pore-called elevated freezing in nanoporous carbons where the adsorbate is thought to take on solid-like densities at temperatures above the bulk freezing point. There is experimental evidence for this phenomenon, but it is open

  7. A two transition state model for radical-molecule reactions : applications to isomeric branching in the OH-isoprene reaction.

    SciTech Connect (OSTI)

    Greenwald, E. E.; North, S. W.; Georgievskii, Y.; Klippenstein, S. J.; Chemistry; Texas A&M Univ.; SNL

    2007-06-28

    A two transition state model is applied to the prediction of the isomeric branching in the addition of hydroxyl radical to isoprene. The outer transition state is treated with phase space theory fitted to long-range transition state theory calculations on an electrostatic potential energy surface. High-level quantum chemical estimates are applied to the treatment of the inner transition state. A one-dimensional master equation based on an analytic reduction from two-dimensions for a particular statistical assumption about the rotational part of the energy transfer kernel is employed in the calculation of the pressure dependence of the addition process. We find that an accurate treatment of the two separate transition state regions, at the energy and angular momentum resolved level, is essential to the prediction of the temperature dependence of the addition rate. The transition from a dominant outer transition state to a dominant inner transition state is shown to occur at about 275 K, with significant effects from both transition states over the 30-500 K temperature range. Modest adjustments in the ab initio predicted inner saddle point energies yield predictions that are in quantitative agreement with the available high-pressure limit experimental observations and qualitative agreement with those in the falloff regime. The theoretically predicted capture rate is reproduced to within 10% by the expression [1.71 x 10-10(T/298)-2.58 exp(-608.6/RT) + 5.47 x 10-11(T/298)-1.78 exp(-97.3/RT); with R = 1.987 and T in K] cm3 molecule-1 s-1 over the 30-500 K range. A 300 K branching ratio of 0.67:0.02:0.02:0.29 was determined for formation of the four possible OH-isoprene adduct isomers 1, 2, 3, and 4, respectively, and was found to be relatively insensitive to temperature. An Arrhenius activation energy of -0.77 kcal/mol was determined for the high-pressure addition rate constants around 300 K.

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

    E-Print Network [OSTI]

    Jean-Pierre Eckmann; Lai-Sang Young

    2010-07-04

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

  9. Modeling the coupling of reaction kinetics and hydrodynamics in a collapsing cavity Sudib K. Mishra a,*, P.A. Deymier b

    E-Print Network [OSTI]

    Deymier, Pierre

    Modeling the coupling of reaction kinetics and hydrodynamics in a collapsing cavity Sudib K. Mishra Available online 22 May 2009 Keywords: Cavitation Reaction Multiphase Lattice Boltzmann Model Stochastic a b s t r a c t We introduce a model of cavitation based on the multiphase Lattice Boltzmann method (LBM

  10. 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.

    2001-11-09

    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.

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

    SciTech Connect (OSTI)

    Wang, M.Q.

    1996-06-01

    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.

  12. Large deviation generating function for energy transport in the Pauli-Fierz model

    E-Print Network [OSTI]

    Wojciech De Roeck

    2007-11-14

    We consider a finite quantum system coupled to quasifree thermal reservoirs at different temperatures. Under the assumptions of small coupling and exponential decay of the reservoir correlation function, the large deviation generating function of energy transport into the reservoirs is shown to be analytic on a bounded set. Our method is different from the spectral deformation technique which was employed recently in the study of spin-boson-like models. As a corollary, we derive the Gallavotti-Cohen fluctuation relation for the entropy production and a central limit theorem for energy transport.

  13. Conditional stochastic modeling of transport of contaminant in the vadose zone. Final project report

    SciTech Connect (OSTI)

    Yeh, T.C.J.; Harter, T.

    1995-06-01

    Spatial heterogeneity media leads to uncertainty in predicting both flow and transport in the vadose zone. In this work an efficient and flexible, combined analytical-numerical Monte Carlo approach is developed for the analysis of steady-state flow and transient transport processes in highly heterogeneous, variably saturated porous media. The approach is also used for the investigation of the validity of linear, first order analytical stochastic models. A combined analytical-numerical conditional simulation algorithm is developed to estimate the impact of in-situ soil hydraulic measurements on reducing the uncertainty of concentration and solute flux predictions.

  14. Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake

    E-Print Network [OSTI]

    Stroud, Jonathan

    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

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

    E-Print Network [OSTI]

    2007-01-01

    Journal of Power Sources 164 (2007) 189195 Modeling water transport in liquid feed direct methanol management in direct methanol fuel cells (DMFCs) is very critical and complicated because of many interacting rights reserved. Keywords: Direct methanol fuel cell; Water transport; Mathematical modeling; Three

  16. Local thermal equilibrium for certain stochastic models of heat transport

    E-Print Network [OSTI]

    Yao Li; Peter Nandori; Lai-Sang Young

    2015-05-08

    This paper is about nonequilibrium steady states (NESS) of a class of stochastic models in which particles exchange energy with their "local environments" rather than directly with one another. The physical domain of the system can be a bounded region of $\\mathbb R^d$ for any $d \\ge 1$. We assume that the temperature at the boundary of the domain is prescribed and is nonconstant, so that the system is forced out of equilibrium. Our main result is local thermal equilibrium in the infinite volume limit. In the Hamiltonian context, this would mean that at any location $x$ in the domain, local marginal distributions of NESS tend to a probability with density $\\frac{1}{Z} e^{-\\beta (x) H}$, permitting one to define the local temperature at $x$ to be $\\beta(x)^{-1}$. We prove also that in the infinite volume limit, the mean energy profile of NESS satisfies Laplace's equation for the prescribed boundary condition. Our method of proof is duality: by reversing the sample paths of particle movements, we convert the problem of studying local marginal energy distributions at $x$ to that of joint hitting distributions of certain random walks starting from $x$, and prove that the walks in question become increasingly independent as system size tends to infinity.

  17. Modeling of Breaching Due to Overtopping Flow and Waves Based on Coupled Flow and Sediment Transport

    E-Print Network [OSTI]

    He, Zhiguo; Zhao, Liang; Wu, Ganfeng; Phtz, Thomas

    2015-01-01

    Breaching of earthen or sandy dams/dunes by overtopping flow and waves is a complicated process with strong, unsteady flow, high sediment transport, and rapid bed changes in which the interactions between flow and morphology should not be ignored. This study presents a depth-averaged two-dimensional (2D) coupled flow and sediment transport model to investigate the flow and breaching processes with and without waves. Bed change and variable flow density are included in the flow continuity and momentum equations to consider the impacts of sediment transport. The model adopts the non-equilibrium approach for total-load sediment transport and specifies different repose angles to handle non-cohesive embankment slope avalanching. The equations are solved using an explicit finite volume method on a rectangular grid with the improved Godunov-type central upwind scheme and the nonnegative reconstruction of the water depth method to handle mixed-regime flows near the breach. The model has been tested against two sets o...

  18. 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-

    2004-01-01

    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 ...

  19. 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 with rotational symmetry in systems with circular geometry. We also find standing waves consisting of periodic

  20. Characterizing Indoor Airflow and Pollutant Transport using Simulation Modeling for Prototypical Buildings. I. Office Buildings

    SciTech Connect (OSTI)

    Sohn, M.D.; Daisey, J.M.; Feustel, H.E.

    1999-06-01

    This paper describes the first efforts at developing a set of prototypical buildings defined to capture the key features affecting airflow and pollutant transport in buildings. These buildings will be used to model airflow and pollutant transport for emergency response scenarios when limited site-specific information is available and immediate decisions must be made, and to better understand key features of buildings controlling occupant exposures to indoor pollutant sources. This paper presents an example of this approach for a prototypical intermediate-sized, open style, commercial building. Interzonal transport due to a short-term source release, e.g., accidental chemical spill, in the bottom and the upper floors is predicted and corresponding HVAC system operation effects and potential responses are considered. Three-hour average exposure estimates are used to compare effects of source location and HVAC operation.

  1. Reactive chemical transport in ground-water hydrology: Challenges to mathematical modeling

    SciTech Connect (OSTI)

    Narasimhan, T.N.; Apps, J.A.

    1990-07-01

    For a long time, earth scientists have qualitatively recognized that mineral assemblages in soils and rocks conform to established principles of chemistry. In the early 1960's geochemists began systematizing this knowledge by developing quantitative thermodynamic models based on equilibrium considerations. These models have since been coupled with advective-dispersive-diffusive transport models, already developed by ground-water hydrologists. Spurred by a need for handling difficult environmental issues related to ground-water contamination, these models are being improved, refined and applied to realistic problems of interest. There is little doubt that these models will play an important role in solving important problems of engineering as well as science over the coming years. Even as these models are being used practically, there is scope for their improvement and many challenges lie ahead. In addition to improving the conceptual basis of the governing equations, much remains to be done to incorporate kinetic processes and biological mediation into extant chemical equilibrium models. Much also remains to be learned about the limits to which model predictability can be reasonably taken. The purpose of this paper is to broadly assess the current status of knowledge in modeling reactive chemical transport and to identify the challenges that lie ahead.

  2. 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

    2009-01-01

    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.

  3. A detailed surface reaction model for syngas production from butane over Rhodium catalyst

    E-Print Network [OSTI]

    Daraio, Chiara

    online 30 July 2011 Keywords: Butane reforming Surface reaction mechanism Micro solid oxide fuel cell a b solid oxide fuel cells (micro SOFCs) have promising potential to provide an alternative al. [16] reported the optimization of a detailed reaction mechanism for methane combustion

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

    E-Print Network [OSTI]

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

    2004-09-06

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

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

    SciTech Connect (OSTI)

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

    2008-09-01

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

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

    SciTech Connect (OSTI)

    MURAD, SOHAIL; JAMESON, CYNTHIA J

    2013-10-22

    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

  7. Directed transport in equilibrium : analysis of the dimer model with inertial terms

    E-Print Network [OSTI]

    A. Bhattacharyay

    2011-08-15

    We have previously shown an analysis of our dimer model in the over-damped regime to show directed transport in equilibrium. Here we analyze the full model with inertial terms present to establish the same result. First we derive the Fokker-Planck equation for the system following a Galilean transformation to show that a uniformly translating equilibrium distribution is possible. Then, we find out the velocity selection for the centre of mass motion using that distribution on our model. We suggest generalization of our calculations for soft collision potentials and indicate to interesting situation with possibility of oscillatory non-equilibrium state within equilibrium.

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

    SciTech Connect (OSTI)

    Chen, K.F.

    2001-02-22

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

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

    SciTech Connect (OSTI)

    Hufnagel, Todd C.

    2014-06-09

    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.

  10. A general methodology for quantum modeling of free-energy profile of reactions in solution: An application to the Menshutkin NH3 CH3Cl

    E-Print Network [OSTI]

    Truong, Thanh N.

    A general methodology for quantum modeling of free-energy profile of reactions in solution methodology for calculating free-energy profile of reaction in solution using quantum mechanical methods of molecules in solution, quantum model- ing of free-energy profile in solution still remains a challenge.1

  11. Equilibrium calculation of transport coefficients for a fluid-particle model

    E-Print Network [OSTI]

    Thomas Ihle; Erkan Tuzel; Daniel M. Kroll

    2005-09-26

    A recently introduced particle-based model for fluid flow, called Stochastic Rotation Dynamics, can be made Galilean invariant by introducing a random shift of the computational grid before collisions. In this paper, it is shown how the Green-Kubo relations derived previously can be resummed to obtain exact expressions for the collisional contributions to the transport coefficients. It is also shown that the collisional contribution to the microscopic stress tensor is not symmetric, and that this leads to an additional viscosity. The resulting identification of the transport coefficients for the hydrodynamic modes is discussed in detail, and it is shown that this does not impose restrictions on the applicability of the model. The collisional contribution to the thermal conductivity, which becomes important for small mean free path and small average particle number per cell, is also derived.

  12. 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

    2009-01-01

    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 ...

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

    SciTech Connect (OSTI)

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

    2008-03-13

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

  14. FRIGA, A New Approach To Identify Isotopes and Hypernuclei In N-Body Transport Models

    E-Print Network [OSTI]

    A. Le Fvre; Y. Leifels; J. Aichelin; Ch. Hartnack; V. Kireyev; E. Bratkovskaya

    2015-09-22

    We present a new algorithm to identify fragments in computer simulations of relativistic heavy ion collisions. It is based on the simulated annealing technique and can be applied to n-body transport models like the Quantum Molecular Dynamics. This new approach is able to predict isotope yields as well as hyper-nucleus production. In order to illustrate its predicting power, we confront this new method to experimental data, and show the sensitivity on the parameters which govern the cluster formation.

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

    E-Print Network [OSTI]

    Zhang, Liqing

    2011-07-01

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

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

    SciTech Connect (OSTI)

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

    1992-10-30

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

  17. A Multiphase First Order Model for Non-Equilibrium Sand Erosion, Transport and Sedimentation

    E-Print Network [OSTI]

    Preziosi, Luigi; Bruno, Luca

    2015-01-01

    Three phenomena are involved in sand movement: erosion, wind transport, and sedimentation. This paper presents a comprehensive easy-to-use multiphase model that include all three aspects with a particular attention to situations in which erosion due to wind shear and sedimentation due to gravity are not in equilibrium. The interest is related to the fact that these are the situations leading to a change of profile of the sand bed.

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

    E-Print Network [OSTI]

    Xu, Jun; Ko, Che Ming.

    2011-01-01

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

  19. 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 ...

  20. Mathematical model for oil slick transport and mixing in rivers. Special report

    SciTech Connect (OSTI)

    Shen, H.T.; Yapa, P.D.; Wang, D.S.; Yang, X.Q.

    1993-08-01

    The growing concern over the impacts of oil spills on aquatic environments has led to the development of many computer models for simulating the transport and spreading of oil slicks in surface waters. Almost all of these models were developed for coastal environments. A few river models exist. These models only considered the movement of surface oil slicks. In this study a two-layer model, ROSS2, is developed for simulating oil spills in rivers. This model considers the oil in the river to consist of a surface slick and suspended oil droplets entrained over the depth of the flow. The oil transformation processes considered in the model include advection, mechanical spreading, turbulent diffusion and mixing, evaporation, dissolution, emulsification, shoreline deposition and sinking. The model can be used for simulating instantaneous or continuous spills either on or under the water surface in rivers with or without an ice cover. The model has been implemented for the Ohio-Monongahela-Allegheny river system and the upper St. Lawrence River. This report describes the model formulation and implementation. A case study is presented along with detailed explanations of the program structure and its input and output. Although it is developed for simulating oil spills, the model can be applied to spills of other hazardous materials. Computer models, Oil spills, Oil slicks, Rivers.

  1. Incorporation of Reaction Kinetics into a Multiphase, Hydrodynamic Model of a Fischer Tropsch Slurry Bubble Column Reactor

    SciTech Connect (OSTI)

    Donna Guillen, PhD; Anastasia Gribik; Daniel Ginosar, PhD; Steven P. Antal, PhD

    2008-11-01

    This paper describes the development of a computational multiphase fluid dynamics (CMFD) model of the Fischer Tropsch (FT) process in a Slurry Bubble Column Reactor (SBCR). The CMFD model is fundamentally based which allows it to be applied to different industrial processes and reactor geometries. The NPHASE CMFD solver [1] is used as the robust computational platform. Results from the CMFD model include gas distribution, species concentration profiles, and local temperatures within the SBCR. This type of model can provide valuable information for process design, operations and troubleshooting of FT plants. An ensemble-averaged, turbulent, multi-fluid solution algorithm for the multiphase, reacting flow with heat transfer was employed. Mechanistic models applicable to churn turbulent flow have been developed to provide a fundamentally based closure set for the equations. In this four-field model formulation, two of the fields are used to track the gas phase (i.e., small spherical and large slug/cap bubbles), and the other two fields are used for the liquid and catalyst particles. Reaction kinetics for a cobalt catalyst is based upon values reported in the published literature. An initial, reaction kinetics model has been developed and exercised to demonstrate viability of the overall solution scheme. The model will continue to be developed with improved physics added in stages.

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

    E-Print Network [OSTI]

    Harper, Michael Richard, Jr

    2011-01-01

    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 ...

  3. 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.

    1985-01-01

    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.

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

    SciTech Connect (OSTI)

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

    1985-01-01

    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.

  5. Modeling preasymptotic transport in flows with significant inertial and trapping effects The importance of velocity correlations and a spatial

    E-Print Network [OSTI]

    Bolster, Diogo

    , demonstrated that at asymptotic times, for laminar flow conditions transport in a cylindrical tube canModeling preasymptotic transport in flows with significant inertial and trapping effects Borgne b , Jrmy Bouquain b , Phillipe Davy b a Environmental Fluid Dynamics Laboratories, Dept

  6. Fluid transport properties by equilibrium molecular dynamics. III. Evaluation of united atom interaction potential models for pure alkanes

    E-Print Network [OSTI]

    Dysthe, Dag Kristian

    Received 2 August 1999; accepted 9 February 2000 Results of new simulations for n-butane, n-decane, n and density of transport property studies by MD of n-butane, n-decane, and n-hexadecane using flexible, mul- tisite molecular models. In the case of n-butane there have been performed at least 14 transport

  7. Self-consistent three-dimensional model of dust particle transport and formation of Coulomb crystals in plasma processing reactors

    E-Print Network [OSTI]

    Kushner, Mark

    Self-consistent three-dimensional model of dust particle transport and formation of Coulomb, University of Illinois, Urbana, Illinois 61801 Gregory A. Hebnerb) Sandia National Laboratories, Albuquerque of Illinois, Urbana, Illinois 61801 Received 24 June 2002; accepted 30 August 2002 Dust particle transport

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

    SciTech Connect (OSTI)

    NSTec Radioactive Waste

    2010-10-12

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

  9. Low-energy pions in nuclear matter and pi pi photoproduction within a BUU transport model

    E-Print Network [OSTI]

    Oliver Buss; Luis Alvarez-Ruso; Pascal Muehlich; Ulrich Mosel; Radhey Shyam

    2005-02-11

    In the present paper we investigate a method to describe low-energy scattering events of pions and nuclei within a Boltzmann-Uehling-Uhlenbeck (BUU) transport model. Implementing different scenarios of medium modifications, we studied the mean free path of pions in nuclear matter at low momenta and compared pion absorption simulations to data. Pursuing these studies we have shown, that also in a regime of a long pionic wave length the semi-classical BUU model still generates reasonable results. We present results on pi-induced events in the regime of 10 MeV energies of 400-460 MeV.

  10. Improved Geothermometry Through Multivariate Reaction-path Modeling and Evaluation of Geomicrobiological Influences on Geochemical Temperature Indicators: Final Report

    SciTech Connect (OSTI)

    Mattson, Earl; Smith, Robert; Fujita, Yoshiko; McLing, Travis; Neupane, Ghanashyam; Palmer, Carl; Reed, David; Thompson, Vicki

    2015-03-01

    The project was aimed at demonstrating that the geothermometric predictions can be improved through the application of multi-element reaction path modeling that accounts for lithologic and tectonic settings, while also accounting for biological influences on geochemical temperature indicators. The limited utilization of chemical signatures by individual traditional geothermometer in the development of reservoir temperature estimates may have been constraining their reliability for evaluation of potential geothermal resources. This project, however, was intended to build a geothermometry tool which can integrate multi-component reaction path modeling with process-optimization capability that can be applied to dilute, low-temperature water samples to consistently predict reservoir temperature within 30 C. The project was also intended to evaluate the extent to which microbiological processes can modulate the geochemical signals in some thermal waters and influence the geothermometric predictions.

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

    E-Print Network [OSTI]

    Bobskill, Glenn James

    1988-01-01

    ? Vibrational energy lost during single dissociation F ? Free energy at standard pressure G ? Vibrational energy gained during single recombination h ? Heat of formation at standard pressure h ? Enthalpy k ? Backward reaction rate coefficient k ? Forward... to describe this kinetic process are fundamentally based on the dissociation of a pure diatomic gas as derived from thermochemical concepts. several past and present investigations have produced viable models which are included within the present...

  12. 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

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

    SciTech Connect (OSTI)

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

    2006-12-20

    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.

  14. Estimating Bacteria Emissions from Inversion of Atmospheric Transport: Sensitivity to Modelled Particle Characteristics

    SciTech Connect (OSTI)

    Burrows, Susannah M.; Rayner, Perter; Butler, T.; Lawrence, M.

    2013-06-04

    Model-simulated transport of atmospheric trace components can be combined with observed concentrations to obtain estimates of ground-based sources using various inversion techniques. These approaches have been applied in the past primarily to obtain source estimates for long-lived trace gases such as CO2. We consider the application of similar techniques to source estimation for atmospheric aerosols, by using as a case study the estimation of bacteria emissions from different ecosystem regions in the global atmospheric chemistry and climate model ECHAM5/MESSy-Atmospheric Chemistry (EMAC). Simulated particle concentrations in the tropopause region and at high latitudes, as well as transport of particles to tundra and land ice regions are shown to be highly sensitive to scavenging in mixed-phase clouds, which is poorly characterized in most global climate models. This may be a critical uncertainty in correctly simulating the transport of aerosol particles to the Arctic. Source estimation via Monte Carlo Markov Chain is applied to a suite of sensitivity simulations and the global mean emissions are estimated. We present an analysis of the partitioning of uncertainties in the global mean emissions that are attributable to particle size, CCN activity, the ice nucleation scavenging ratios for mixed-phase and cold clouds, and measurement error. Uncertainty due to CCN activity or to a 1 um error in particle size is typically between 10% and 40% of the uncertainty due to data uncertainty, as measured by the 5%-ile to 95%-ile range of the Monte Carlo ensemble. Uncertainty attributable to the ice nucleation scavenging ratio in mized-phase clouds is as high as 10% to 20% of the data uncertainty. Taken together, the four model 20 parameters examined contribute about half as much to the uncertainty in the estimated emissions as do the measurements. This was a surprisingly large contribution from model uncertainty in light of the substantial data uncertainty, which ranges from 81% to 870% for each of ten ecosystems for this case study. The effects of these and other model parameters in contributing to the uncertainties in the transport of atmospheric aerosol particles should be treated explicitly and systematically in both forward and inverse modelling studies.

  15. Environmental fate and transport of chemical signatures from buried landmines -- Screening model formulation and initial simulations

    SciTech Connect (OSTI)

    Phelan, J.M.; Webb, S.W.

    1997-06-01

    The fate and transport of chemical signature molecules that emanate from buried landmines is strongly influenced by physical chemical properties and by environmental conditions of the specific chemical compounds. Published data have been evaluated as the input parameters that are used in the simulation of the fate and transport processes. A one-dimensional model developed for screening agricultural pesticides was modified and used to simulate the appearance of a surface flux above a buried landmine, estimate the subsurface total concentration, and show the phase specific concentrations at the ground surface. The physical chemical properties of TNT cause a majority of the mass released to the soil system to be bound to the solid phase soil particles. The majority of the transport occurs in the liquid phase with diffusion and evaporation driven advection of soil water as the primary mechanisms for the flux to the ground surface. The simulations provided herein should only be used for initial conceptual designs of chemical pre-concentration subsystems or complete detection systems. The physical processes modeled required necessary simplifying assumptions to allow for analytical solutions. Emerging numerical simulation tools will soon be available that should provide more realistic estimates that can be used to predict the success of landmine chemical detection surveys based on knowledge of the chemical and soil properties, and environmental conditions where the mines are buried. Additional measurements of the chemical properties in soils are also needed before a fully predictive approach can be confidently applied.

  16. Modeling the Energy Use of a Connected and Automated Transportation System (Poster)

    SciTech Connect (OSTI)

    Gonder, J.; Brown, A.

    2014-07-01

    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.

  17. Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 episodic events in southern Lake

    E-Print Network [OSTI]

    Numerical modeling of mixed sediment resuspension, transport, and deposition during the March 1998 sediment resuspension of mixed (cohesive plus noncohesive) sediment is developed and applied to quantitatively simulate the March 1998 resuspension events in southern Lake Michigan. Some characteristics

  18. 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.; Rognlien, T. D.; Lasnier, C. J.; Unterberg, E.

    2014-06-15

    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.

  19. Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode

    SciTech Connect (OSTI)

    Pigarov, A. Yu.; Krasheninnikov, S. I.; Rognlien, T. D.; Hollmann, E. M.; Lasnier, C. J.; Unterberg, Ezekial A

    2014-01-01

    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.

  20. 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.

    2006-06-01

    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.

  1. STRAIN-INDUCED STRUCTURAL CHANGES AND CHEMICAL REACTIONSII. MODELLING OF REACTIONS

    E-Print Network [OSTI]

    Meyers, Marc A.

    for large strains. It is analytically demonstrated that intense plastic deformation can accelerate chemical recently been shown experimentally that shear localization in plastic deformation of a reac- tive mixture of these reactions inside shear bands are pre- sented for NbSi and TiSi mixtures; a thermodynamic and kinetic

  2. Simplification of the tug-of-war model for cellular transport in cells

    E-Print Network [OSTI]

    Yunxin Zhang

    2010-07-07

    The transport of organelles and vesicles in living cells can be well described by a kinetic tug-of-war model advanced by M\\"uller, Klumpp and Lipowsky. In which, the cargo is attached by two motor species, kinesin and dynein, and the direction of motion is determined by the number of motors which bind to the track. In recent work [Phys. Rev. E 79, 061918 (2009)], this model was studied by mean field theory, and it was found that, usually the tug-of-war model has one, two, or three distinct stable stationary points. However, the results there are mostly obtained by numerical calculations, since it is hard to do detailed theoretical studies to a two-dimensional nonlinear system. In this paper, we will carry out further detailed analysis about this model, and try to find more properties theoretically. Firstly, the tug-of-war model is simplified to a one-dimensional equation. Then we claim that the stationary points of the tug-of-war model correspond to the roots of the simplified equation, and the stable stationary points correspond to the roots with positive derivative. Bifurcation occurs at the corresponding parameters, under which the simplified one-dimensional equation exists root with zero derivative. Using the simplified equation, not only more properties of the tug-of-war model can be obtained analytically, the related numerical calculations will become more accurate and more efficient. This simplification will be helpful to future studies of the tug-of-war model.

  3. 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.; Moffat, H.K.

    1996-02-01

    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.

  4. 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

    2014-10-07

    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.

  5. 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

    2014-01-01

    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.

  6. Monte Carlo modeling of transport in PbSe nanocrystal films

    SciTech Connect (OSTI)

    Carbone, I. Carter, S. A.; Zimanyi, G. T.

    2013-11-21

    A Monte Carlo hopping model was developed to simulate electron and hole transport in nanocrystalline PbSe films. Transport is carried out as a series of thermally activated hopping events between neighboring sites on a cubic lattice. Each site, representing an individual nanocrystal, is assigned a size-dependent electronic structure, and the effects of particle size, charging, interparticle coupling, and energetic disorder on electron and hole mobilities were investigated. Results of simulated field-effect measurements confirm that electron mobilities and conductivities at constant carrier densities increase with particle diameter by an order of magnitude up to 5?nm and begin to decrease above 6?nm. We find that as particle size increases, fewer hops are required to traverse the same distance and that site energy disorder significantly inhibits transport in films composed of smaller nanoparticles. The dip in mobilities and conductivities at larger particle sizes can be explained by a decrease in tunneling amplitudes and by charging penalties that are incurred more frequently when carriers are confined to fewer, larger nanoparticles. Using a nearly identical set of parameter values as the electron simulations, hole mobility simulations confirm measurements that increase monotonically with particle size over two orders of magnitude.

  7. 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

    2015-01-14

    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.

  8. Mesoscopic modeling of multi-physicochemical transport phenomena in porous media

    SciTech Connect (OSTI)

    Kang, Qinjin; Wang, Moran; Mukherjee, Partha P; Lichtner, Peter C

    2009-01-01

    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.

  9. Asymmetric quantum transport in a double-stranded Kronig-Penney model

    E-Print Network [OSTI]

    Taksu Cheon; Sergey S. Poghosyan

    2015-03-03

    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.

  10. The freeze-out properties of hyperons in a microscopic transport model

    E-Print Network [OSTI]

    Xie, Zhenglian; Bass, Steffen A

    2009-01-01

    The excitation function of freeze-out time, average freeze-out temperature and freeze-out energy density of (multi-) strange baryons created in relativistic heavy-ion collisions is investigated in the framework of a microscopic transport model. We find that the Omega on average freezes out earlier than the nucleon, Xi and Lambda. The average freeze-out temperature and energy density as well as the spread between the different baryonicstates increase monotonously with increasing beam energy and should approach a universal value in the case of a hadronizing Quark-Gluon-Plasma.

  11. The freeze-out properties of hyperons in a microscopic transport model

    E-Print Network [OSTI]

    Zhenglian Xie; Pingzhi Ning; Steffen A. Bass

    2009-11-23

    The excitation function of freeze-out time, average freeze-out temperature and freeze-out energy density of (multi-) strange baryons created in relativistic heavy-ion collisions is investigated in the framework of a microscopic transport model. We find that the Omega on average freezes out earlier than the nucleon, Xi and Lambda. The average freeze-out temperature and energy density as well as the spread between the different baryonicstates increase monotonously with increasing beam energy and should approach a universal value in the case of a hadronizing Quark-Gluon-Plasma.

  12. 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

    2011-09-30

    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.

  13. Hypergraphic Oriented Matroid Relational Dependency Flow Models of Chemical Reaction Networks

    E-Print Network [OSTI]

    Bailey, C G; Oliveira, J S

    2009-01-01

    In this paper we derive and present an application of hypergraphic oriented matroids for the purpose of enumerating the variable interdependencies that define the chemical complexes associated with the kinetics of non-linear dynamical system representations of chemical kinetic reaction flow networks. The derivation of a hypergraphic oriented matroid is obtained by defining a closure operator on families of n-subsets of signed multi-sets from which a "Z-module" is obtained. It has been observed that every instantiation of the closure operator on the signed multiset families define a matroid structure. It is then demonstrated that these structures generate a pair of dual matroids corresponding respectively to hyperspanning trees and hypercycles obtained from the corresponding directed hypergraphs. These structures are next systematically evaluated to obtain solution sets that satisfy systems of non-linear chemical kinetic reaction flow networks in the MAP Kinase cascade cell-signaling pathway.

  14. 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

    2008-01-01

    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 ...

  15. Constraint-Based Routing Models for the Transport of Radioactive Materials

    SciTech Connect (OSTI)

    Peterson, Steven K

    2015-01-01

    The Department of Energy (DOE) has a historic programmatic interest in the safe and secure routing, tracking, and transportation risk analysis of radiological materials in the United States. In order to address these program goals, DOE has funded the development of several tools and related systems designed to provide insight to planners and other professionals handling radioactive materials shipments. These systems include the WebTRAGIS (Transportation Routing Analysis Geographic Information System) platform. WebTRAGIS is a browser-based routing application developed at Oak Ridge National Laboratory (ORNL) focused primarily on the safe transport of spent nuclear fuel from US nuclear reactors via railway, highway, or waterway. It is also used for the transport planning of low-level radiological waste to depositories such as the Waste Isolation Pilot Plant (WIPP) facility. One particular feature of WebTRAGIS is its coupling with high-resolution population data from ORNL s LandScan project. This allows users to obtain highly accurate population count and density information for use in route planning and risk analysis. To perform the routing and risk analysis WebTRAGIS incorporates a basic routing model methodology, with the additional application of various constraints designed to mimic US Department of Transportation (DOT), DOE, and Nuclear Regulatory Commission (NRC) regulations. Aside from the routing models available in WebTRAGIS, the system relies on detailed or specialized modal networks for the route solutions. These include a highly detailed network model of the US railroad system, the inland and coastal waterways, and a specialized highway network that focuses on the US interstate system and the designated hazardous materials and Highway Route Controlled Quantity (HRCQ) -designated roadways. The route constraints in WebTRAGIS rely upon a series of attributes assigned to the various components of the different modal networks. Routes are determined via a constrained shortest-path Dijkstra algorithm that has an assigned impedance factor. The route constraints modify the various impedance weights to bias or prefer particular network characteristics as desired by the user. Both the basic route model and the constrained impedance function calculations are determined by a series of network characteristics and shipment types. The study examines solutions under various constraints modeled by WebTRAGIS including possible routes from select shut-down reactor sites in the US to specific locations in the US. For purposes of illustration, the designated destinations are Oak Ridge National Laboratory in Tennessee and the Savannah River Site in South Carolina. To the degree that routes express sameness or variety under constraints serves to illustrate either a) the determinism of particular transport modes by either configuration or regulatory compliance, and/or b) the variety of constrained routes that are regulation compliant but may not be operationally feasible.

  16. Applying GIS characterizing and modeling contaminant transport in surface water at Los Alamos National Laboratory

    SciTech Connect (OSTI)

    Becker, N.M.; Van Eeckhout, E.; David, N.A.; Irvine, J.M.

    1995-10-01

    During World War II, Los Alamos, New Mexico was chosen as the site for the secret development of the first atomic bomb. The remote location in the southwestern United States was ideal for such a project. After the war, research activities continued at the Los Alamos installation, focusing on new nuclear weapons models as well as greater effectiveness and reliability of existing weapons. Due to the emphasis on nuclear and non-nuclear weapons development as well as associated nuclear research, a large inventory of radionuclides and heavy metals have been tested, expended, and disposed of in the local environment, a high plateau of tuffaceous volcanic rocks incised by deep canyons in a semi-arid climate. In recent years an intensive evaluation of the environmental, impact of weapons testing at Los Alamos and elsewhere has been undertaken. GIS system utilization and image processing of past and current data has been an important part of this evaluation. Important problems can be more easily displayed and understood using this methodology. The main objective in this paper is to illustrate how transport of depleted uranium and associated heavy metals (copper in this case) used in dynamic testing of weapons components at open air firing sites can be evaluated and visualized. In our studies, surface water has been found to be the predominant transport mechanism. We have sampled soils, sediments, fallout, runoff water and snowmelt over a number of years in order to understand contaminant transport on- and offsite. Statistical analyses of these data have assisted in our characterization of issues such as contaminant variability, spatially and temporally, as well as in development of transport rates.

  17. Urban airshed modeling of air quality impacts of alternative transportation fuel use in Los Angeles and Atlanta

    SciTech Connect (OSTI)

    NONE

    1997-12-01

    The main objective of NREL in supporting this study is to determine the relative air quality impact of the use of compressed natural gas (CNG) as an alternative transportation fuel when compared to low Reid vapor pressure (RVP) gasoline and reformulated gasoline (RFG). A table lists the criteria, air toxic, and greenhouse gas pollutants for which emissions were estimated for the alternative fuel scenarios. Air quality impacts were then estimated by performing photochemical modeling of the alternative fuel scenarios using the Urban Airshed Model Version 6.21 and the Carbon Bond Mechanism Version IV (CBM-IV) (Geary et al., 1988) Using this model, the authors examined the formation and transport of ozone under alternative fuel strategies for motor vehicle transportation sources for the year 2007. Photochemical modeling was performed for modeling domains in Los Angeles, California, and Atlanta, Georgia.

  18. 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

    2010-04-22

    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.

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

    SciTech Connect (OSTI)

    Turner, Daniel Zack

    2012-01-01

    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.

  20. Asymptotic Analysis of Complex Automata models for Reaction-Diffusion systems

    E-Print Network [OSTI]

    by many single scale models, constructed to simulate the rele- vant sub-processes, choosing appropriately

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

    SciTech Connect (OSTI)

    K. Rehfeldt

    2004-10-08

    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).

  2. 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

    2013-01-01

    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...

  3. Three-dimensional transport and concentration of SF{sub 6} - a model intercomparison study (transcom 2)

    SciTech Connect (OSTI)

    Denning, A.S.; Holzer, M.; Burney, K.R.; Heimann, M.; Law, R.M.; Rayner, P.J.; Fund, I.Y.; Fan, S.M.; Taguchi, S.; Friedlingstein, P.; Balkanski, Y.; Taylor, J.; Maiss, M.; Levin, I.

    1999-01-02

    Sulfur hexafluoride (SF6) is an excellent tracer of large-scale atmospheric transport, because it has slowly increasing sources mostly confined to northern midlatitudes, and has a lifetime of thousands of years. We have simulated the emissions, transport, and concentration of SF, for a 5-year period, and compared the results with atmospheric observations. In addition, we have performed an intercomparison of interhemispheric transport among 11 models to investigate the reasons for the differences among the simulations. Most of the models are reasonably successful at simulating the observed meridional gradient of SF6 in the remote marine boundary layer, though there is less agreement at continental sites. Models that compare well to observations in the remote marine boundary layer tend to systematically overestimate SF6 at continental locations in source regions, suggesting that vertical trapping rather than meridional transport may be a dominant control on the simulated meridional gradient. The vertical structure of simulated SF6 in the models supports this interpretation. Some of the models perform quite well in terms of the simulated seasonal cycle at remote locations, while others do not. Interhemispheric exchange time varies by a factor of 2 when estimated from 1-dimensional meridional profiles at the surface, as has been done for observations. The agreement among models is better when the global surface mean mole fraction is used, and better still when the full 3-dimensional mean mixing ratio is used. The ranking of the interhemispheric exchange time among the models is not sensitive to the change From station values to surface means, but is very sensitive to the change from surface means to the full 3-dimensional tracer fields. This strengthens the argument that vertical redistribution dominates over interhemispheric transport in determining the meridional gradient at the surface. Vertically integrated meridional transport in the models is divided roughly equally into transport by the mean motion, the standing eddies, and the transient eddies. The vertically integrated mass flux is a good index of the degree to which resolved advection vs. parameterized diffusion accomplishes the meridional transport of SF6. Observational programs could provide a much better constraint on simulated chemical tracer transport if they included regular sampling of vertical profiles of nonreactive trace gases over source regions and meridional profiles in the middle to upper troposphere. Further analysis of the SF6 simulations will focus on the subgrid-scale parameterized transports.

  4. International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR MODELLING FOR LIGHT VEHICLES

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    - 1 - 16th International Conference 'Transport and Air Pollution' 2008, Graz EMISSION FACTOR in Europe: The European MEET (Methodologies for Estimating air pollutant Emissions from Transport) project. Transport and Air Pollution, Graz : Austria (2008)" #12;- 2 - 16th International Conference 'Transport

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

    E-Print Network [OSTI]

    M. Katsuma

    2014-04-15

    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.

  6. Uranium Fate and Transport Modeling, Guterl Specialty Steel Site, New York - 13545

    SciTech Connect (OSTI)

    Frederick, Bill; Tandon, Vikas

    2013-07-01

    The Former Guterl Specialty Steel Corporation Site (Guterl Site) is located 32 kilometers (20 miles) northeast of Buffalo, New York, in Lockport, Niagara County, New York. Between 1948 and 1952, up to 15,875 metric tons (35 million pounds) of natural uranium metal (U) were processed at the former Guterl Specialty Steel Corporation site in Lockport, New York. The resulting dust, thermal scale, mill shavings and associated land disposal contaminated both the facility and on-site soils. Uranium subsequently impacted groundwater and a fully developed plume exists below the site. Uranium transport from the site involves legacy on-site pickling fluid handling, the leaching of uranium from soil to groundwater, and the groundwater transport of dissolved uranium to the Erie Canal. Groundwater fate and transport modeling was performed to assess the transfer of dissolved uranium from the contaminated soils and buildings to groundwater and subsequently to the nearby Erie Canal. The modeling provides a tool to determine if the uranium contamination could potentially affect human receptors in the vicinity of the site. Groundwater underlying the site and in the surrounding area generally flows southeasterly towards the Erie Canal; locally, groundwater is not used as a drinking water resource. The risk to human health was evaluated outside the Guterl Site boundary from the possibility of impacted groundwater discharging to and mixing with the Erie Canal waters. This condition was evaluated because canal water is infrequently used as an emergency water supply for the City of Lockport via an intake located approximately 122 meters (m) (400 feet [ft]) southeast of the Guterl Site. Modeling was performed to assess whether mixing of groundwater with surface water in the Erie Canal could result in levels of uranium exceeding the U.S. Environmental Protection Agency (USEPA) established drinking water standard for total uranium; the Maximum Concentration Limit (MCL). Geotechnical test data indicate that the major portion of uranium in the soil will adsorb or remain bound to soil, yet leaching to groundwater appears as an on-site source. Soil leaching was modeled using low adsorption factors to replicate worst-case conditions where the uranium leaches to the groundwater. Results indicate that even after several decades, which is the period of time since uranium was processed at the Guterl Site, leaching from soil does not fully account for the currently observed levels of groundwater contamination. Modeling results suggest that there were historic releases of uranium from processing operations directly to the shallow fractured rock and possibly other geochemical conditions that have produced the current groundwater contamination. Groundwater data collected at the site between 1997 and 2011 do not indicate an increasing level of uranium in the main plume, thus the uranium adsorbed to the soil is in equilibrium with the groundwater geochemistry and transport conditions. Consequently, increases in the overall plume concentration or size are not expected. Groundwater flowing through fractures under the Guterl Site transports dissolved uranium from the site to the Erie Canal, where the groundwater has been observed to seep from the northern canal wall at some locations. The seeps discharge uranium at concentrations near or below the MCL to the Erie Canal. Conservative mixing calculations were performed using two worst-case assumptions: 1) the seeps were calculated as contiguous discharges from the Erie Canal wall and 2) the uranium concentration of the seepage is 274 micrograms per liter (?g/L) of uranium, which is the highest on-site uranium concentration in groundwater and nearly ten-fold the actual seep concentrations. The results indicate that uranium concentrations in the seep water would have to be more than 200 times greater than the highest observed on-site groundwater concentrations (or nearly 55,000 ?g/L) to potentially exceed the drinking water standard (the MCL) for total uranium in the Erie Canal. (authors)

  7. A model for motor-mediated bidirectional transport along an antipolar microtubule bundle

    E-Print Network [OSTI]

    Congping Lin; Peter Ashwin; Gero Steinberg

    2012-11-21

    Long-distance bidirectional transport of organelles depends on the motor proteins kinesin and dynein. Using quantitative data obtained from a fungal model system, we previously developed ASEP-models of bidirectional motion of motors along unipolar microtubules (MTs) near the cell ends of the elongated hyphal cells (herein referred as "unipolar section"). However, recent quantitative live cell imaging in this system has demonstrated that long-range motility of motors and their endosomal cargo mainly occurs along extended antipolar microtubule bundles within the central part of the cell (herein referred to as "bipolar section"). Dynein and kinesin-3 motors coordinate their activity to move early endosomes (EEs) in a bidirectional fashion, with dynein mediating retrograde motility along the unipolar section near the cell poles, whereas kinesin-3 is responsible for bidirectional motions along the antipolar section. Here we extend our modelling approach to simulate bidirectional motility along an antipolar microtubule bundle. In our model, cargos (particles) change direction on each MT with a turning rate $\\Omega$ and the MTs are linked to each other at the minus ends where particles can hop between MTs with a rate $q_1$ (obstacle-induced switching rate) or $q_2$ (end-induced switching rate). By numerical simulations and mean-field approximations, we investigate the distribution of particles along the MTs for different overall densities $\\Theta$. We find that even if $\\Theta$ is low, the system can exhibit shocks in the density profiles near plus and minus ends caused by queueing of particles. We also discuss how the switching rates $q_{1,2}$ influence the type of motor that dominates the active transport in the bundle.

  8. Comprehensive inverse modeling for the study of carrier transport models in sub-50nm MOSFETs

    E-Print Network [OSTI]

    Djomehri, Ihsan Jahed, 1976-

    2002-01-01

    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 ...

  9. MELTER: A model of the thermal response of cargos transported in the Safe-Secure Trailer subject to fire environments for risk assessment applications

    SciTech Connect (OSTI)

    Larsen, M.E.

    1994-08-01

    MELTER is an analysis of cargo responses inside a fire-threatened Safe-Secure Trailer (SST) developed for the Defense Program Transportation Risk Assessment (DPTRA). Many simplifying assumptions are required to make the subject problem tractable. MELTER incorporates modeling which balances the competing requirements of execution speed, generality, completeness of essential physics, and robustness. Input parameters affecting the analysis include those defining the fire scenario, those defining the cargo loaded in the SST, and those defining properties of the SST. For a specified fire, SST, and cargo geometry MELTER predicts the critical fire duration that will lead to a failure. The principal features of the analysis include: (a) Geometric considerations to interpret fire-scenario descriptors in terms of a thermal radiation boundary condition, (b) a simple model of the SST`s wall combining the diffusion model for radiation through optically-thick media with an endothermic reaction front to describe the charring of dimensional, rigid foam in the SST wall, (c) a transient radiation enclosure model, (d) a one-dimensional, spherical idealization of the shipped cargos providing modularity so that cargos of interest can be inserted into the model, and (e) associated numerical methods to integrate coupled, differential equations and find roots.

  10. Mesoscale Phase-Field Modeling of Charge Transport in Nanocomposite Electrodes for Lithium-ion Batteries

    SciTech Connect (OSTI)

    Hu, Shenyang Y.; Li, Yulan; Rosso, Kevin M.; Sushko, Maria L.

    2013-01-10

    A phase-field model is developed to investigate the influence of microstructure, thermodynamic and kinetic properties, and charging conditions on charged particle transport in nanocomposite electrodes. Two sets of field variables are used to describe the microstructure. One is comprised of the order parameters describing size, orientation and spatial distributions of nanoparticles, and the other is comprised of the concentrations of mobile species. A porous nanoparticle microstructure filled with electrolyte is taken as a model system to test the phase-field model. Inhomogeneous and anisotropic dielectric constants and mobilities of charged particles, and stresses associated with lattice deformation due to Li-ion insertion/extraction are considered in the model. Iteration methods are used to find the elastic and electric fields in an elastically and electrically inhomogeneous medium. The results demonstrate that the model is capable of predicting charge separation associated with the formation of a double layer at the electrochemical interface between solid and electrolyte, and the effect of microstructure, inhomogeneous and anisotropic thermodynamic and kinetic properties, charge rates, and stresses on voltage versus current density and capacity during charging and discharging.

  11. Biochimica et BiophysicaActa, 726 (1983) 265-292 265 MODEL REACTIONS IN PHOTOSYNTHESIS

    E-Print Network [OSTI]

    Boxer, Steven G.

    1983-01-01

    of this field from the particular perspective of attempts to model photosynthesis in artificial systems .................................................................................. 288 I. What are we trying to model? 1A. Introduction Photosynthesis involves a very large number. In addition, models in photosynthesis research play a prominent role in testing theoretical concepts

  12. 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.

    2012-03-19

    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.

  13. A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions

    E-Print Network [OSTI]

    Rose, William I.

    A multidisciplinary effort to assign realistic source parameters to models of volcanic ash: volcanic eruption aircraft volcanic plumes ash clouds During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days

  14. Modeling of particle and energy transport in the edge plasma of Alcator C-Mod

    SciTech Connect (OSTI)

    Umansky, M.V.; Krasheninnikov, S.I.; LaBombard, B.; Lipschultz, B.; Terry, J.L. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1999-07-01

    In the present study recycling and transport in the edge plasma of Alcator C-Mod [I. H. Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)] is modeled and analyzed with the multi-fluid code UEDGE [T. D. Rognlien {ital et al.}, J. Nucl. Mater. {bold 196{endash}198}, 347 (1992)]. Matching the experimental plasma density profiles in the scrape-off layer (SOL) requires a spatially dependent effective anomalous diffusion coefficient D{sub {perpendicular}} growing rapidly towards the wall. The midplane pressure of neutral gas, P{sub mid}, is a key parameter that reflects the magnitude of anomalous transport of plasma from the core. Recycling of plasma on the main chamber wall appears to be quite significant, especially in the case of high P{sub mid}{approximately}0.3 mTorr when the main wall provides {approximately}70{percent} of recycling neutrals in the main chamber. In the upper SOL (well above the {ital x} point) draining of particles by the poloidal flow is weak and thus the particle balance is predominantly radial. For the radial heat transport it is found that energy flux carried by radial plasma convection and by charge-exchange (CX) neutrals is quite significant in SOL. In the high P{sub mid} case, heat conduction by CX neutrals along with radial heat convection by plasma carries most of the power flux ({approximately}75{percent}) across the last closed flux surface. Even in the low P{sub mid} case, heat conduction by CX neutrals dominates the radial heat flux far out in the SOL. {copyright} {ital 1999 American Institute of Physics.}

  15. ACCELERATION OF LOW-ENERGY IONS AT PARALLEL SHOCKS WITH A FOCUSED TRANSPORT MODEL

    SciTech Connect (OSTI)

    Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K.

    2013-04-10

    We present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by parallel shocks with a focused transport model. The focused transport equation contains all necessary physics of shock acceleration, but avoids the limitation of diffusive shock acceleration (DSA) that requires a small pitch angle anisotropy. This simulation verifies that the particles with speeds of a fraction of to a few times the shock speed can indeed be directly injected and accelerated into the DSA regime by parallel shocks. At higher energies starting from a few times the shock speed, the energy spectrum of accelerated particles is a power law with the same spectral index as the solution of standard DSA theory, although the particles are highly anisotropic in the upstream region. The intensity, however, is different from that predicted by DSA theory, indicating a different level of injection efficiency. It is found that the shock strength, the injection speed, and the intensity of an electric cross-shock potential (CSP) jump can affect the injection efficiency of the low-energy particles. A stronger shock has a higher injection efficiency. In addition, if the speed of injected particles is above a few times the shock speed, the produced power-law spectrum is consistent with the prediction of standard DSA theory in both its intensity and spectrum index with an injection efficiency of 1. CSP can increase the injection efficiency through direct particle reflection back upstream, but it has little effect on the energetic particle acceleration once the speed of injected particles is beyond a few times the shock speed. This test particle simulation proves that the focused transport theory is an extension of DSA theory with the capability of predicting the efficiency of particle injection.

  16. Transportation Sector Model of the National Energy Modeling System. Volume 2 -- Appendices: Part 3

    SciTech Connect (OSTI)

    NONE

    1998-01-01

    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.

  17. Transportation Sector Demand Module of the National Energy Modeling System: Model Documentation

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home PageMonthly","10/2015"4,"Ames5 Tables July 1996 Energy Information Administration Office of Coal,Demand Module of the National Energy Modeling System: Model Documentation

  18. Transportation Sector Module of the National Energy Modeling System: Model Documentation

    U.S. Energy Information Administration (EIA) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home PageMonthly","10/2015"4,"Ames5 Tables July 1996 Energy Information Administration Office of Coal,Demand Module of the National Energy Modeling System: ModelModule of the

  19. 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.

    1970-01-01

    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 mass), have been measured...

  20. 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

    2008-07-07

    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.

  1. Spin densities from subsystem density-functional theory: Assessment and application to a photosynthetic reaction center complex model

    SciTech Connect (OSTI)

    Solovyeva, Alisa [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany); Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Technical University Braunschweig, Institute for Physical and Theoretical Chemistry, Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)

    2012-05-21

    Subsystem density-functional theory (DFT) is a powerful and efficient alternative to Kohn-Sham DFT for large systems composed of several weakly interacting subunits. Here, we provide a systematic investigation of the spin-density distributions obtained in subsystem DFT calculations for radicals in explicit environments. This includes a small radical in a solvent shell, a {pi}-stacked guanine-thymine radical cation, and a benchmark application to a model for the special pair radical cation, which is a dimer of bacteriochlorophyll pigments, from the photosynthetic reaction center of purple bacteria. We investigate the differences in the spin densities resulting from subsystem DFT and Kohn-Sham DFT calculations. In these comparisons, we focus on the problem of overdelocalization of spin densities due to the self-interaction error in DFT. It is demonstrated that subsystem DFT can reduce this problem, while it still allows to describe spin-polarization effects crossing the boundaries of the subsystems. In practical calculations of spin densities for radicals in a given environment, it may thus be a pragmatic alternative to Kohn-Sham DFT calculations. In our calculation on the special pair radical cation, we show that the coordinating histidine residues reduce the spin-density asymmetry between the two halves of this system, while inclusion of a larger binding pocket model increases this asymmetry. The unidirectional energy transfer in photosynthetic reaction centers is related to the asymmetry introduced by the protein environment.

  2. High-resolution pollutant transport in the San Pedro Bay of California

    E-Print Network [OSTI]

    Cohan, Alexander; Wu, Jun; Dabdub, Donald

    2011-01-01

    mixing with chemical?reaction in the planetarytransportandnotchemicalreactions. Hence,while cold

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

    E-Print Network [OSTI]

    K. P. Sinha; A. Meulenberg

    2009-01-16

    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.

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

    E-Print Network [OSTI]

    Sinha, K P

    2009-01-01

    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.

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

    E-Print Network [OSTI]

    Oll Pocurull, Bernat

    2007-01-01

    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. A coarse-grained transport model for neutral particles in turbulent plasmas

    SciTech Connect (OSTI)

    Mekkaoui, A.; Reiter, D.; Boerner, P. [IEK-4 Plasmaphysik, Forschungszentrum Juelich GmbH, Euratom Association, D-52425 Juelich (Germany); Marandet, Y.; Genesio, P.; Rosato, J.; Capes, H.; Koubiti, M.; Godbert-Mouret, L.; Stamm, R. [Aix-Marseille Universite, CNRS, PIIM, UMR 7345, F-13397 Marseille Cedex 20 (France)

    2012-12-15

    The transport of neutral particles in turbulent plasmas is addressed from the prospect of developing coarse-grained transport models which can be implemented in code suites like B2-EIRENE, currently used for designing the ITER divertor. The statistical properties of turbulent fluctuations are described by a multivariate Gamma distribution able to retain space and time correlations through a proper choice of covariance function. We show that in the scattering free case, relevant for molecules and impurity atoms, the average neutral particle density obeys a Boltzmann equation with an ionization rate renormalized by fluctuations. This result lends itself to a straightforward implementation in the EIRENE Monte Carlo solver for neutral particles. Special emphasis is put on the inclusion of time correlations, and in particular on the ballistic motion of coherent turbulent structures. The role of these time dependent effects is discussed for D{sub 2} molecules and beryllium atoms. The sensitivity of our results to the assumptions on the statistical properties of fluctuations is investigated.

  7. Transport theory for cold relativistic superfluids from an analogue model of gravity

    E-Print Network [OSTI]

    Massimo Mannarelli; Cristina Manuel

    2008-02-04

    We write a covariant transport equation for the phonon excitations of a relativistic superfluid valid at small temperatures. The hydrodynamical equations for this system are derived from the effective field theory associated to the superfluid phonons. We describe how to construct the kinetic theory for the phonon quasiparticles using a relativistic generalization of the analogue model of gravity developed by Unruh. This gravity analogy relies on the equivalence between the action of a phonon field moving in a superfluid background with that of a boson propagating in a given curved space-time. Exploiting this analogy we obtain continuity equations for the phonon current, entropy and energy-momentum tensor in a covariant form, valid in any reference frame. Our aim is to shed light on some aspects of transport phenomena of relativistic superfluidity. In particular, we are interested in the low temperature regime of the color flavor locked phase, which is a color superconducting and superfluid phase of high density QCD that may be realized in the core of neutron stars.

  8. 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

    2006-12-07

    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.

  9. Anisotropic parton escape is the dominant source of azimuthal anisotropy in transport models

    E-Print Network [OSTI]

    Liang He; Terrence Edmonds; Zi-Wei Lin; Feng Liu; Denes Molnar; Fuqiang Wang

    2015-07-02

    We trace the development of elliptic anisotropy ($v_2$) via parton-parton collision history in two transport models. The parton $v_2$ is studied as a function of the number of collisions of each parton in Au+Au and $d$+Au collisions at $\\sqrt{s_{_{\\rm NN}}}=200$~GeV. It is found that the majority of $v_2$ comes from the anisotropic escape probability of partons, with no fundamental difference at low and high transverse momenta. The contribution to $v_2$ from hydrodynamic-type collective flow is found to be small. Only when the parton-parton cross-section is set unrealistically large does this contribution start to take over. Our findings challenge the current paradigm emerged from hydrodynamic comparisons to anisotropy data.

  10. Transport properties of dense dissipitive hard-sphere fluids for arbitrary energy loss models

    E-Print Network [OSTI]

    James F. Lutsko

    2005-03-17

    The revised Enskog approximation for a fluid of hard spheres which lose energy upon collision is discussed for the case that the energy is lost from the normal component of the velocity at collision but is otherwise arbitrary. Granular fluids with a velocity-dependent coefficient of restitution are an important special case covered by this model. A normal solution to the Enskog equation is developed using the Chapman-Enskog expansion. The lowest order solution describes the general homogeneous cooling state and a generating function formalism is introduced for the determination of the distribution function. The first order solution, evaluated in the lowest Sonine approximation, provides estimates for the transport coefficients for the Navier-Stokes hydrodynamic description. All calculations are performed in an arbitrary number of dimensions.

  11. Analysis of ground-water contaminant transport with three-dimensional scaled models. Technical completion report, 1 May 88-30 Apr 89

    SciTech Connect (OSTI)

    Sill, B.L.

    1991-04-01

    A three dimensional scale model was designed and built to simulate the transport of a solute in the groundwater at a known location. The study was undertaken to further validate a new method of groundwater transport modeling which has been under development at Clemson University, using mixtures of cement, sand and water to simulate the subsurface matrix. By comparing field measurements with laboratory simulations, it was judged that transport times and concentrations were modeled satisfactorily.

  12. Modeling regional transportation demand in China and the impacts of a national carbon constraint

    E-Print Network [OSTI]

    Kishimoto, Paul

    2015-01-30

    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, ...

  13. A general performance model for parallel sweeps on orthogonal grids for particle transport calculations

    E-Print Network [OSTI]

    Mathis, Mark Michael

    2000-01-01

    There is a growing need to accurately simulate physical systems whose evolution depends on the transport of subatomic particles. It has long been recognized that the huge computational demands of the transport problem mean that practical solution...

  14. Mechanisms in knockout reactions

    E-Print Network [OSTI]

    D. Bazin; R. J. Charity; R. T. de Souza; M. A. Famiano; A. Gade; V. Henzl; D. Henzlova; S. Hudan; J. Lee; S. Lukyanov; W. G. Lynch; S. McDaniel; M. Mocko; A. Obertelli; A. M. Rogers; L. G. Sobotka; J. R. Terry; J. A. Tostevin; M. B. Tsang; M. S. Wallace

    2009-02-16

    We report on the first detailed study of the mechanisms involved in knockout reactions, via a coincidence measurement of the residue and fast proton in one-proton knockout reactions, using the S800 spectrograph in combination with the HiRA detector array at the NSCL. Results on the reactions $^9$Be($^9$C,$^8$B+X)Y and $^9$Be($^8$B,$^7$Be+X)Y are presented. They are compared with theoretical predictions for both the diffraction and stripping reaction mechanisms, as calculated in the eikonal model. The data shows a clear distinction between the two reaction mechanisms, and the observed respective proportions are very well reproduced by the reaction theory. This agreement supports the results of knockout reaction analyses and their applications to the spectroscopy of rare isotopes.

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

    E-Print Network [OSTI]

    Lachance, Russell Philip

    2005-01-01

    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 ...

  16. The diffusion of photovoltaics : background, modeling and initial reaction of the agricultural - irrigation sector

    E-Print Network [OSTI]

    Lilien, Gary Louis

    1978-01-01

    This paper deals with the background, development and calibration of a model of innovation-diffusion, designed to help allocate government field test and demonstration resources in support of a photovoltaic technology ...

  17. Modeling vertical and horizontal solute transport for the Weldon Spring Site Remedial Action Project

    SciTech Connect (OSTI)

    Tomasko, D.

    1992-11-01

    This technical memorandum presents a one-dimensional model to simulate the transport of a contaminant that originates as a liquid release, moves vertically downward through a vadose zone, mixes with initially clean groundwater in an unconfined aquifer, and ends at a downgradient extraction well. Vertical and horizontal segments of the contaminant pathway are coupled by assuming that the breakthrough curve of the contaminant at the water table acts as a contaminant source for the unconfined aquifer. For simplicity, this source is assumed to be a time-shifted unit square wave having an amplitude equal to the peak breakthrough concentration at the water table and a duration equal to the full width of the breakthrough curve at the half-maximum concentration value. The effects of dilution at the water-table interface are evaluated with a simple mass-balance equation. Comparing the model results for the chemical plant area of the Weldon Spring site near St. Louis, Missouri, and the Envirocare facility located near Salt Lake City, Utah, with those obtained from a solution formulated with the real and imaginary parts of a Fourier series in Laplace space indicates that the model provides a conservative estimate of the contaminant breakthrough curve at the receptor.

  18. Transportation Secure Data Center: Real-world Data for Planning, Modeling, and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2015-01-01

    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.

  19. Verifying the Accuracy of Land Use Models Used in Transportation and Air Quality: A Case Study in the Sacramento, California Region

    E-Print Network [OSTI]

    Rodier, Caroline J.

    2005-01-01

    A Case Study in the Sacramento Region (Ph.D. Dissertation,Analysis using the Sacramento MEPLAN Land Use Transportationin the MEPLAN model of Sacramento. Transportation Research

  20. Final Technical Report - Stochastic Analysis of Advection-Diffusion-reaction Systems with Applications to Reactive Transport in Porous Media - DE-FG02-07ER24818

    SciTech Connect (OSTI)

    Karniadakis, George Em

    2014-03-11

    The main objective of this project is to develop new computational tools for uncertainty quantifica- tion (UQ) of systems governed by stochastic partial differential equations (SPDEs) with applications to advection-diffusion-reaction systems. We pursue two complementary approaches: (1) generalized polynomial chaos and its extensions and (2) a new theory on deriving PDF equations for systems subject to color noise. The focus of the current work is on high-dimensional systems involving tens or hundreds of uncertain parameters.

  1. 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.

    2012-09-24

    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

  2. Economic Model Predictive Control: Handling Preventive Actuator and Sensor Maintenance and Application to Transport-Reaction Processes

    E-Print Network [OSTI]

    Lao, Liangfeng

    2015-01-01

    beds. Industrial & Engineering Chemistry, 41:11791184,processes. Industrial & Engineering Chemistry Research, 34:processes. Industrial & Engineering Chemistry Research, 53:

  3. Economic Model Predictive Control: Handling Preventive Actuator and Sensor Maintenance and Application to Transport-Reaction Processes

    E-Print Network [OSTI]

    Lao, Liangfeng

    2015-01-01

    Nonlinear Analysis in Chemical Engineering. McGraw-Hillorder reduction. Chemical Engineering Science, 57:50835114,the next revolution. Chemical Engineering Progress, [17] H.

  4. Economic Model Predictive Control: Handling Preventive Actuator and Sensor Maintenance and Application to Transport-Reaction Processes

    E-Print Network [OSTI]

    Lao, Liangfeng

    2015-01-01

    a) temperature, (b) heat rate, and (c) flow rate profilesa) temperature, (b) heat rate, and (c) flow rate profilesa) temperature, (b) heat rate, and (c) flow rate profiles

  5. 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

    2003-07-28

    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.

  6. 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 separation or postulate a spherical shrinking-core phase boundary under all conditions, by predicting phase

  7. The application of selective reaction monitoring shows dysregulation of glycolysis in a preclinical model of schizophrenia

    E-Print Network [OSTI]

    Martins-de-Souza, Daniel; Alsaif, Murtada; Ernst, Agnes; Harris, Laura W.; Aerts, Nancy; Lenaerts, Ilse; Peeters, Pieter J.; Amess, Bob; Rahmoune, Hassan; Bahn, Sabine; Guest, Paul C.

    2012-03-15

    models. Clin Schizophr Relat Psychoses 2010, 4(3) :189-200. 4. Gao XM, Shirakawa O, Du F, Tamminga CA: Delayed regional metabolic actions of phencyclidine. Eur J Pharmacol 1993, 241(1) :7-15. 5. Iltis I, Koski DM, Eberly LE, Nelson CD, Deelchand DK...

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

    E-Print Network [OSTI]

    Knoll, Alex Baxter

    2014-07-30

    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...

  9. A Novel Model for Fracture Acidizing with Important Thermal Effects

    E-Print Network [OSTI]

    Lyons, John

    2013-12-05

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.1.3 LB Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3. MODELING REACTIVE TRANSPORT . . . . . . . . . . . . . . . . . . . . . 14 3.1 LB Method: Fluid Velocity Update . . . . . . . . . . . . . . . . . . . . . 14 3.2 LB... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 6.2 Diffusion and Reaction in a Closed Box . . . . . . . . . . . . . . . . . . 37 6.3 Advection, Diffusion and Reaction in an Open Channel . . . . . . . . . . 38 7. THERMAL FRACTURE ACIDIZING MODEL . . . . . . . . . . . . . . . . . 40 7.1 Velocity...

  10. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

    SciTech Connect (OSTI)

    Converse, Alexander K. [Univ. of Wisconsin, Madison, WI (United States); Ahlers, Elizabeth O. [Univ. of Wisconsin, Madison, WI (United States); Bryan, Tom W. [Univ. of Wisconsin, Madison, WI (United States); Hetue, Jackson D. [Univ. of Wisconsin, Madison, WI (United States); Lake, Katherine A. [Univ. of Wisconsin, Madison, WI (United States); Ellison, Paul A. [Univ. of Wisconsin, Madison, WI (United States); Engle, Jonathan W. [Univ. of Wisconsin, Madison, WI (United States); Barnhart, Todd E. [Univ. of Wisconsin, Madison, WI (United States); Nickles, Robert J. [Univ. of Wisconsin, Madison, WI (United States); Williams, Paul H. [Univ. of Wisconsin, Madison, WI (United States); DeJesus, Onofre T. [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-01

    Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [?F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modeling of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [?F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.

  11. Computer Modeling of Transport of Oxidizing Species in Grain Boundaries during Zirconium Corrosion

    SciTech Connect (OSTI)

    Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks

    2014-06-01

    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.

  12. 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

    2008-05-01

    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.

  13. A covariant model for the $?^\\ast N \\to N^\\ast(1520)$ reaction

    E-Print Network [OSTI]

    G. Ramalho; M. T. Pena

    2014-02-03

    We apply the covariant spectator quark model to the study of the electromagnetic structure of the $N^\\ast(1520)$ state ($J^{P}= \\frac{3}{2}^-$), an important resonance from the second resonance region in both spacelike and timelike regimes. The contributions from the valence quark effects are calculated for the $\\gamma^\\ast N \\to N^\\ast(1520)$ helicity amplitudes. The results are used to parametrize the meson cloud dominant at low $Q^2$.

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

    E-Print Network [OSTI]

    Freezing and thawing a b s t r a c t Numerous cold regions water flow and energy transport models have. Simulated and/or observed climate change impacts in cryogenic soils include permafrost degradation, active that include the dynamic freezethaw process have been tested against analytical solutions, such as the Neumann

  15. Transport of oxygen in soil pore-water systems: implications for modeling emissions of carbon dioxide and methane

    E-Print Network [OSTI]

    andaresignificantsourcesofgreenhousegases,including carbon dioxide (CO2) and methane (CH4) emissions. The traditional approachTransport of oxygen in soil pore-water systems: implications for modeling emissions of carbon of CH4 is 24 times greater than that of carbon dioxide (CO2) over a 100-year time scale (Ramaswamy et al

  16. Solutions of burnt-bridge models for molecular motor transport Alexander Yu. Morozov, Ekaterina Pronina, and Anatoly B. Kolomeisky

    E-Print Network [OSTI]

    Solutions of burnt-bridge models for molecular motor transport Alexander Yu. Morozov, Ekaterina consecutive binding sites called "bridges" , is investigated theoretically by analyzing discrete-state stochastic "burnt-bridge" mod- els. When an unbiased diffusing particle crosses the bridge, the link can

  17. GROUNDWATER FLOW AND TRANSPORT MODELING Application to Submarine Groundwater Discharge, Coastal Wetland Hydrology, and Deep Well Injection

    E-Print Network [OSTI]

    Sukop, Mike

    GROUNDWATER FLOW AND TRANSPORT MODELING Application to Submarine Groundwater Discharge, Coastal, but is also lost to surface water drainage and potential submarine groundwater discharge. There are also to deal with issues such as submarine groundwater discharge and coastal wetland hydrology. SEAWAT also has

  18. Radiative Reactions and Coherence Modeling in the High Altitude Electromagnetic Pulse

    E-Print Network [OSTI]

    Charles N. Vittitoe; Mario Rabinowitz

    2003-06-03

    A high altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5 x 10^4 V/m carries momentum that results in a retarding force on the average Compton electron (radiating coherently to produce the waveform) with magnitude near that of the geomagnetic force responsible for the coherent radiation. The retarding force results from a self field effect. The Compton electron interaction with the self generated magnetic field due to the other electrons accounts for the momentum density in the propagating wave; interaction with the self generated electric field accounts for the energy flux density in the propagating wave. Coherent addition of radiation is also quantitatively modeled.

  19. Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Converse, Alexander K.; Ahlers, Elizabeth O.; Bryan, Tom W.; Hetue, Jackson D.; Lake, Katherine A.; Ellison, Paul A.; Engle, Jonathan W.; Barnhart, Todd E.; Nickles, Robert J.; Williams, Paul H.; et al

    2015-03-15

    Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [?F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modelingmoreof fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [?F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitative assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.less

  20. Biomass power plant feedstock procurement: Modeling transportation cost zones and the potential for competition

    E-Print Network [OSTI]

    Kizha., Anil R; Han, Han-Sup; Montgomery, Timothy; Hohl, Aaron

    2015-01-01

    transportation network Green Leaf Power plants Total* $Blue Lake Power and Green Leaf power plants have shut downElectric Company Green Leaf Power Pacific Gas & Electric

  1. Fluctuation level bursts in a model of internal transport barrier formation D. Lopez-Bruna, D. E. Newman, and B. A. Carreras

    E-Print Network [OSTI]

    Newman, David

    features of ITB models the phase transition character with a power threshold, barrier front propagation radial electric field.10,11 As happens with the edge transport barriers, the system reacts to the extraFluctuation level bursts in a model of internal transport barrier formation D. Lopez-Bruna, D. E

  2. Identifying key controls on the behavior of an acidic-U(VI) plume in the Savannah River Site using reactive transport modeling

    E-Print Network [OSTI]

    Hubbard, Susan

    online 1 May 2013 Acidic low-level waste radioactive waste solutions were discharged to three unlined reactive transport modeling Sergio A. Bea a, , Haruko Wainwright a,1 , Nicolas Spycher a,2 , Boris treatments. This paper presents a reactive transport (RT) model and uncertainty quantification (UQ) analyses

  3. Vehicle Technologies Office Merit Review 2015: Transportation Energy Transition Modeling and Analysis: the LAVE-Trans Model

    Office of Energy Efficiency and Renewable Energy (EERE)

    Presentation given by Oak Ridge National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about transportation...

  4. Radiative reactions and coherence modeling in the high-altitude electromagnetic pulse

    SciTech Connect (OSTI)

    Vittitoe, C.N.; Rabinowitz, M.

    1988-03-15

    A high-altitude nuclear electromagnetic pulse (EMP) with a peak field intensity of 5 x 10/sup 4/ V/m carries momentum that results in a retarding force on the average Compton electron (radiating coherently to produce the waveform) with magnitude near that of the geomagnetic force responsible for the coherent radiation. The retarding force results from a self-field effect. The Compton electron interaction with the self-generated magnetic field due to the other electrons accounts for the momentum density in the propagating wave; interaction with the self-generated electric field accounts for the energy-flux density in the propagating wave. Coherent addition of radiation is also quantitatively modeled.

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

    SciTech Connect (OSTI)

    Khorrami, Mohammad Aghamohammadi, Amir

    2014-03-15

    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.

  6. Nuclear Reactions

    E-Print Network [OSTI]

    C. A. Bertulani

    2010-07-14

    Nuclear reactions generate energy in nuclear reactors, in stars, and are responsible for the existence of all elements heavier than hydrogen in the universe. Nuclear reactions denote reactions between nuclei, and between nuclei and other fundamental particles, such as electrons and photons. A short description of the conservation laws and the definition of basic physical quantities is presented, followed by a more detailed account of specific cases: (a) formation and decay of compound nuclei; (b)direct reactions; (c) photon and electron scattering; (d) heavy ion collisions; (e) formation of a quark-gluon plasma; (f) thermonuclear reactions; (g) and reactions with radioactive beams. Whenever necessary, basic equations are introduced to help understand general properties of these reactions. Published in Wiley Encyclopedia of Physics, ISBN-13: 978-3-527-40691-3 - Wiley-VCH, Berlin, 2009.

  7. 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

  8. Developing a robust geochemical and reactive transport model to evaluate possible sources of arsenic at the CO[subscript 2] sequestration natural analog site in Chimayo, New Mexico

    SciTech Connect (OSTI)

    Viswanathan, Hari; Dai, Zhenxue; Lopano, Christina; Keating, Elizabeth; Hakala, J. Alexandra; Scheckel, Kirk G.; Zheng, Liange; Gutherie, George D.; Pawar, Rajesh

    2012-10-24

    Migration of carbon dioxide (CO{sub 2}) from deep storage formations into shallow drinking water aquifers is a possible system failure related to geologic CO{sub 2} sequestration. A CO{sub 2} leak may cause mineral precipitation/dissolution reactions, changes in aqueous speciation, and alteration of pH and redox conditions leading to potential increases of trace metal concentrations above EPA National Primary Drinking Water Standards. In this study, the Chimayo site (NM) was examined for site-specific impacts of shallow groundwater interacting with CO{sub 2} from deep storage formations. Major ion and trace element chemistry for the site have been previously studied. This work focuses on arsenic (As), which is regulated by the EPA under the Safe Drinking Water Act and for which some wells in the Chimayo area have concentrations higher than the maximum contaminant level (MCL). Statistical analysis of the existing Chimayo groundwater data indicates that As is strongly correlated with trace metals U and Pb indicating that their source may be from the same deep subsurface water. Batch experiments and materials characterization, such as: X-ray diffraction (XRD), scanning electron microscopy (SEM), and synchrotron micro X-ray fluorescence ({mu}-XRF), were used to identify As association with Fe-rich phases, such as clays or oxides, in the Chimayo sediments as the major factor controlling As fate in the subsurface. Batch laboratory experiments with Chimayo sediments and groundwater show that pH decreases as CO{sub 2} is introduced into the system and buffered by calcite. The introduction of CO{sub 2} causes an immediate increase in As solution concentration, which then decreases over time. A geochemical model was developed to simulate these batch experiments and successfully predicted the pH drop once CO{sub 2} was introduced into the experiment. In the model, sorption of As to illite, kaolinite and smectite through surface complexation proved to be the key reactions in simulating the drop in As concentration as a function of time in the batch experiments. Based on modeling, kaolinite precipitation is anticipated to occur during the experiment, which allows for additional sorption sites to form with time resulting in the slow decrease in As concentration. This mechanism can be viewed as trace metal 'scavenging' due to sorption caused secondary mineral precipitation. Since deep geologic transport of these trace metals to the shallow subsurface by brine or CO{sub 2} intrusion is critical to assessing environmental impacts, the effective retardation of trace metal transport is an important parameter to estimate and it is dependent on multiple coupled reactions. At the field scale, As mobility is retarded due to the influence of sorption reactions, which can affect environmental performance assessment studies of a sequestration site.

  9. Speeding chemical reactions by focusing

    E-Print Network [OSTI]

    A. M. Lacasta; L. Ramirez-Piscina; J. M. Sancho; K. Lindenberg

    2012-12-13

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  10. Hybrid multiscale simulation of a mixing-controlled reaction

    SciTech Connect (OSTI)

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

    2015-09-01

    Continuum-scale models have been used to study subsurface flow, transport, and reactions for many years but lack the capability to resolve fine-grained processes. Recently, pore-scale models, which operate at scales of individual soil grains, have been developed to more accurately model and study pore-scale phenomena, such as mineral precipitation and dissolution reactions, microbially-mediated surface reactions, and other complex processes. However, these highly-resolved models are prohibitively expensive for modeling domains of sizes relevant to practical problems. To broaden the utility of pore-scale models for larger domains, we developed a hybrid multiscale model that initially simulates the full domain at the continuum scale and applies a pore-scale model only to areas of high reactivity. Since the location and number of pore-scale model regions in the model varies as the reactions proceed, an adaptive script defines the number and location of pore regions within each continuum iteration and initializes pore-scale simulations from macroscale information. Another script communicates information from the pore-scale simulation results back to the continuum scale. These components provide loose coupling between the pore- and continuum-scale codes into a single hybrid multiscale model implemented within the SWIFT workflow environment. In this paper, we consider an irreversible homogenous bimolecular reaction (two solutes reacting to form a third solute) in a 2D test problem. This paper is focused on the approach used for multiscale coupling between pore- and continuum-scale models, application to a realistic test problem, and implications of the results for predictive simulation of mixing-controlled reactions in porous media. Our results and analysis demonstrate that loose coupling provides a feasible, efficient and scalable approach for multiscale subsurface simulations.

  11. Reaction coordinates for electron transfer reactions

    SciTech Connect (OSTI)

    Rasaiah, Jayendran C.; Zhu Jianjun

    2008-12-07

    The polarization fluctuation and energy gap formulations of the reaction coordinate for outer sphere electron transfer are linearly related to the constant energy constraint Lagrangian multiplier m in Marcus' theory of electron transfer. The quadratic dependence of the free energies of the reactant and product intermediates on m and m+1, respectively, leads to similar dependence of the free energies on the reaction coordinates and to the same dependence of the activation energy on the reorganization energy and the standard reaction free energy. Within the approximations of a continuum model of the solvent and linear response of the longitudinal polarization to the electric field in Marcus' theory, both formulations of the reaction coordinate are expected to lead to the same results.

  12. Transportation and its Infrastructure

    E-Print Network [OSTI]

    2007-01-01

    of reduction options/ AERO. Ministry of Transport, Publicfrom aviation with the AERO modeling system Part I.from aviation with the AERO modeling system. Montreal,

  13. co2-transport | netl.doe.gov

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

    Transport Cost Model FENETL CO2 Transport Cost Model About the model: This model was developed to estimate the cost of transporting a user-specified mass rate of CO2 by pipeline...

  14. Cosmic ray transport in heliospheric magnetic structures. I. Modeling background solar wind using the CRONOS magnetohydrodynamic code

    SciTech Connect (OSTI)

    Wiengarten, T.; Kleimann, J.; Fichtner, H.; Khl, P.; Kopp, A.; Heber, B.; Kissmann, R.

    2014-06-10

    The transport of energetic particles such as cosmic rays is governed by the properties of the plasma being traversed. While these properties are rather poorly known for galactic and interstellar plasmas due to the lack of in situ measurements, the heliospheric plasma environment has been probed by spacecraft for decades and provides a unique opportunity for testing transport theories. Of particular interest for the three-dimensional (3D) heliospheric transport of energetic particles are structures such as corotating interaction regions, which, due to strongly enhanced magnetic field strengths, turbulence, and associated shocks, can act as diffusion barriers on the one hand, but also as accelerators of low energy CRs on the other hand as well. In a two-fold series of papers, we investigate these effects by modeling inner-heliospheric solar wind conditions with a numerical magnetohydrodynamic (MHD) setup (this paper), which will serve as an input to a transport code employing a stochastic differential equation approach (second paper). In this first paper, we present results from 3D MHD simulations with our code CRONOS: for validation purposes we use analytic boundary conditions and compare with similar work by Pizzo. For a more realistic modeling of solar wind conditions, boundary conditions derived from synoptic magnetograms via the Wang-Sheeley-Arge (WSA) model are utilized, where the potential field modeling is performed with a finite-difference approach in contrast to the traditional spherical harmonics expansion often utilized in the WSA model. Our results are validated by comparing with multi-spacecraft data for ecliptical (STEREO-A/B) and out-of-ecliptic (Ulysses) regions.

  15. Evaluation of the Atmospheric Transport Model in the MACCS2 Code...

    Office of Environmental Management (EM)

    Terrain effects (CALPUFF) Gaussian Plume Model Lagrangian Puff Model Turbulence Characterization - Atmospheric Stability Classical GP models use a classification...

  16. 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

    2013-08-14

    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.

  17. An aeolian transport model for the selection of dune restoration alternatives

    E-Print Network [OSTI]

    Bell, James Clayton

    2007-04-25

    . Following the storm, the Pointe San Luis Property Owner's Association contacted Texas A&M University to design a dune restoration strategy. The greatest natural contributor to dune reconstruction is the available sand delivered by aeolian transport. During...

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

    E-Print Network [OSTI]

    Zheng, L.

    2011-01-01

    Studies on the Transport of Benzene and H 2 S in CO 2 -WaterSolubility measurements of benzene and the alkylbenzenes inDeguchi, 1987. Solubility benzene-hydrocarbon binary mixture

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

    E-Print Network [OSTI]

    Na, Hyeong Suk

    2014-05-01

    disasters, the need for appropriate evacuation strategies has grown dramatically. Providing rapid medical treatment is of utmost importance in such circumstances. The problem of transporting patients to medical facilities is a subject of research that has...

  20. 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 ...

  1. Computations and modeling of oil transport between piston lands and liner in internal combustion engines

    E-Print Network [OSTI]

    Fang, Tianshi

    2014-01-01

    The consumption of lubricating oil in internal combustion engines is a continuous interest for engine developers and remains to be one of the least understood areas. A better understanding on oil transport is critical to ...

  2. 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 ...

  3. The Evaluation of Transportation and Land Use Plans Using Linked Economic and GIS Models

    E-Print Network [OSTI]

    Johnston, Robert A.

    1995-01-01

    urban economyand and economic evaluations. for devlsing andAttempts to base the economic evaluation travel no state isEvaluation of Transportation and Land Use Plans Using Linked Economic

  4. Transportation Secure Data Center: Real-World Data for Planning, Modeling, and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-01-01

    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.

  5. Transportation Secure Data Center: Real-World Data for Planning, Modeling and Analysis (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-01-01

    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.

  6. Feedback Model of Air Transportation System Change: Implementation Challenges for Aviation Information Systems

    E-Print Network [OSTI]

    Mozdzanowska, Aleksandra L.

    The U.S. air transportation system faces substantial challenges in implementing new aviation information systems to meet future demand. These challenges need to be understood and addressed in order to successfully meet ...

  7. 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

    2007-09-01

    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.

  8. Programmability of Chemical Reaction Networks

    E-Print Network [OSTI]

    Winfree, Erik

    Programmability of Chemical Reaction Networks Matthew Cook1 , David Soloveichik2 , Erik Winfree2 Chemical Reaction Networks (SCRNs), a for- mal model that considers a set of chemical reactions acting Logic Circuits, Vector Addition Systems, Petri Nets, Gate Implementability, Primitive Recursive

  9. TransCom N[subscript 2]O model inter-comparison Part 1: Assessing the influence of transport and surface fluxes on tropospheric N[subscript 2]O variability

    E-Print Network [OSTI]

    Thompson, R. L.

    We present a comparison of chemistry-transport models (TransCom-N2O) to examine the importance of atmospheric transport and surface fluxes on the variability of N2O mixing ratios in the troposphere. Six different models ...

  10. Phase II Transport Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Revision 1

    SciTech Connect (OSTI)

    Gregg Ruskuaff

    2010-01-01

    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).

  11. 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.

    1982-03-01

    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.

  12. BETR-world: A geographically explicit model of chemical fate: Application to transport of a-HCH to the arctic

    SciTech Connect (OSTI)

    Toose, Liisa; Woodfine, David G.; MacLeod, Matthew; Mackay, Don; Gouin, Jenn

    2003-12-01

    The Berkeley Trent (BETR)-World model, a 25 compartment, geographically explicit fugacity-based model is described and applied to evaluate the transport of chemicals from temperate source regions to receptor regions (such as the Arctic). The model was parameterized using GIS and an array of digital data on weather, oceans, freshwater, vegetation and geo-political boundaries. This version of the BETR model framework includes modification of atmospheric degradation rates by seasonally variable hydroxyl radical concentrations and temperature. Degradation rates in all other compartments vary with seasonally changing temperature. Deposition to the deep ocean has been included as a loss mechanism. A case study was undertaken for a-HCH. Dynamic emission scenarios were estimated for each of the 25 regions. Predicted environmental concentrations showed good agreement with measured values for the northern regions in air , and fresh and oceanic water and with the results from a previous model of global chemical fate. Potential for long-range transport and deposition to the Arctic region was assessed using a Transfer Efficiency combined with estimated emissions. European regions and the Orient including China have a high potential to contribute a-HCH contamination in the Arctic due to high rates of emission in these regions despite low Transfer Efficiencies. Sensitivity analyses reveal that the performance and reliability of the model is strongly in sequenced by parameters controlling degradation rates.

  13. 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.; Ortoleva, P.; Ozkan, G.; Shebl, M.; Sibo, W.; Tuncay, K.; Sundberg, K.

    1998-07-01

    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.

  14. Combined Modeling of Acceleration, Transport, and Hydrodynamic Response in Solar Flares. II. Inclusion of Radiative Transfer with RADYN

    E-Print Network [OSTI]

    da Costa, Fatima Rubio; Petrosian, Vahe'; Carlsson, Mats

    2015-01-01

    Solar flares involve complex processes that are coupled together and span a wide range of temporal, spatial, and energy scales. Modeling such processes self-consistently has been a challenge in the past. Here we present such a model to simulate the coupling of high-energy particle kinetics with hydrodynamics of the atmospheric plasma. We combine the Stanford unified Fokker-Planck code that models particle acceleration, transport, and bremsstrahlung radiation with the RADYN hydrodynamic code that models the atmospheric response to collisional heating by non-thermal electrons through detailed radiative transfer calculations. We perform simulations using different injection electron spectra, including an {\\it ad hoc} power law and more realistic spectra predicted by the stochastic acceleration model due to turbulence or plasma waves. Surprisingly, stochastically accelerated electrons, even with energy flux $\\ll 10^{10}$ erg s$^{-1}$ cm$^{-2}$, cause "explosive" chromospheric evaporation and drive stronger up- an...

  15. Simulation of oil-slick transport in Great Lakes connecting channels. Volume 1. Theory and model formulation. Final report

    SciTech Connect (OSTI)

    Shen, H.T.; Yapa, P.D.; Petroski, M.E.

    1986-03-01

    In this study, two computer models named as ROSS and LROSS are developed for simulating oil-slick transport in rivers and lakes, respectively. The oil slick transformation processes considered in these models include advection, spreading, evaporation, and dissolution. These models can be used for slicks of any shape originated from instantaneous or continuous spills in rivers and lakes with or without ice covers. Although developed for the need of the connecting channels in the upper Great Lakes, including the Detroit River, Lake St. Clair, St. Clair River, and St. Marys River, these models are site independent and can be used to other rivers and lakes. The programs are written in FORTRAN programming language to be compatible with FORTRAN77 compiler. The models are designed to be used on both mainframe and microcomputers.

  16. Total reaction cross sections in CEM and MCNP6 at intermediate energies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kerby, Leslie M.; Mashnik, Stepan G.

    2015-05-14

    Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmorethe preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.less

  17. Transportation Conference Speakers - 1

    E-Print Network [OSTI]

    Unknown

    2011-08-17

    Thiamin transport in Escherichia coli is a model system to establish the tolerance of derivatives for transport into the cell. Since little is known about what types of thiamin derivatives may be successfully taken into the cell through...

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

    E-Print Network [OSTI]

    Zheng, L.

    2010-01-01

    BVE 98 inferred data BVE 100 Base model D 0ref model D 0refdata BVE99 inferred data BVE100 base model dispersivity =

  19. 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.

    2007-02-17

    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.

  20. 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

    2007-02-17

    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.