Sample records for dynamic simulation tool

  1. Dynamic wind turbine models in power system simulation tool

    E-Print Network [OSTI]

    Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D. Hansen, Florin Iov Iov, Poul Sørensen, Nicolaos Cutululis, Clemens Jauch, Frede Blaabjerg Title: Dynamic wind turbine system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second

  2. Automating efficiency-targeted approximations in modelling and simulation tools: dynamic decoupling and mixed-mode

    E-Print Network [OSTI]

    Como, Giacomo

    Automating efficiency-targeted approximations in modelling and simulation tools: dynamic decoupling (classical) efficiency-targeted approximation tech- niques, within a unified framework. Some application

  3. ulvacsim.paper.doc 08/20/99 p. 1 of 23 Dynamic Simulation of a Multichamber CVD Cluster Tool

    E-Print Network [OSTI]

    Rubloff, Gary W.

    ulvacsim.paper.doc 08/20/99 p. 1 of 23 Dynamic Simulation of a Multichamber CVD Cluster Tool N-level dynamic simulator for an 8" CVD cluster tool (ULVAC-ERA1000). The simulator incorporates models, and volumes to reflect actual behavior, validated against experiments on the Ulvac tool. The process simulator

  4. An Analysis Tool for Flight Dynamics Monte Carlo Simulations

    E-Print Network [OSTI]

    Restrepo, Carolina 1982-

    2011-05-20T23:59:59.000Z

    and analysis work to understand vehicle operating limits and identify circumstances that lead to mission failure. A Monte Carlo simulation approach that varies a wide range of physical parameters is typically used to generate thousands of test cases...

  5. Tools for dynamic model development

    E-Print Network [OSTI]

    Schaber, Spencer Daniel

    2014-01-01T23:59:59.000Z

    For this thesis, several tools for dynamic model development were developed and analyzed. Dynamic models can be used to simulate and optimize the behavior of a great number of natural and engineered systems, from the ...

  6. The Global Nuclear Futures Model: A Dynamic Simulation Tool for Energy Strategies

    SciTech Connect (OSTI)

    Bixler, N.E. [Sandia National Laboratories, Albuquerque, NM 87185-0748 (United States)

    2002-07-01T23:59:59.000Z

    The Global Nuclear Futures Model (GNFM) is a dynamic simulation tool that provides an integrated framework to model key aspects of nuclear energy, nuclear materials storage and disposition, global nuclear materials management, and nuclear proliferation risk. It links nuclear energy and other energy shares dynamically to greenhouse gas emissions and twelve other measures of environmental impact. It presents historical data from 1990 to 2000 and extrapolates energy demand through the year 2050. More specifically, it contains separate modules for energy, the nuclear fuel cycle front end, the nuclear fuel cycle back end, defense nuclear materials, environmental impacts, and measures of the potential for nuclear proliferation. It is globally integrated but also breaks out five regions of the world so that environmental impacts and nuclear proliferation concerns can be evaluated on a regional basis. The five regions are the United States of America (USA), The Peoples Republic of China (China), the former Soviet Union (FSU), the OECD nations excluding the USA, and the rest of the world (ROW). (author)

  7. Automating Dynamic Decoupling in Object-Oriented Modelling and Simulation Tools

    E-Print Network [OSTI]

    Como, Giacomo

    a Modelica transla- tor. Simulation tests demonstrate the technique, and the re- alised implementation than of simulation theory. In this work we refer as "EOO Modelling Tool" to a Modelica translator, to allow exemplifying the (more general) presented ideas. For a Modelica translator, the EOO modelling

  8. Developing an integrated building design tool by coupling building energy simulation and computational fluid dynamics programs

    E-Print Network [OSTI]

    Zhai, Zhiqiang, 1971-

    2003-01-01T23:59:59.000Z

    Building energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing essential information to help design energy-efficient, thermally comfortable and healthy ...

  9. Calibration and Validation of a Spar-Type Floating Offshore Wind Turbine Model using the FAST Dynamic Simulation Tool: Preprint

    SciTech Connect (OSTI)

    Browning, J. R.; Jonkman, J.; Robertson, A.; Goupee, A. J.

    2012-11-01T23:59:59.000Z

    In 2007, the FAST wind turbine simulation tool, developed and maintained by the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL), was expanded to include capabilities that are suitable for modeling floating offshore wind turbines. In an effort to validate FAST and other offshore wind energy modeling tools, DOE funded the DeepCwind project that tested three prototype floating wind turbines at 1/50th scale in a wave basin, including a semisubmersible, a tension-leg platform, and a spar buoy. This paper describes the use of the results of the spar wave basin tests to calibrate and validate the FAST offshore floating simulation tool, and presents some initial results of simulated dynamic responses of the spar to several combinations of wind and sea states.

  10. Molecular dynamics simulation: a tool for exploration and discovery using simple models

    E-Print Network [OSTI]

    D. C. Rapaport

    2014-11-13T23:59:59.000Z

    Emergent phenomena share the fascinating property of not being obvious consequences of the design of the system in which they appear. This characteristic is no less relevant when attempting to simulate such phenomena, given that the outcome is not always a foregone conclusion. The present survey focuses on several simple model systems that exhibit surprisingly rich emergent behavior, all studied by MD simulation. The examples are taken from the disparate fields of fluid dynamics, granular matter and supramolecular self-assembly. In studies of fluids modeled at the detailed microscopic level using discrete particles, the simulations demonstrate that complex hydrodynamic phenomena in rotating and convecting fluids, the Taylor-Couette and Rayleigh-B\\'enard instabilities, can not only be observed within the limited length and time scales accessible to MD, but even quantitative agreement can be achieved. Simulation of highly counterintuitive segregation phenomena in granular mixtures, again using MD methods, but now augmented by forces producing damping and friction, leads to results that resemble experimentally observed axial and radial segregation in the case of a rotating cylinder, and to a novel form of horizontal segregation in a vertically vibrated layer. Finally, when modeling self-assembly processes analogous to the formation of the polyhedral shells that package spherical viruses, simulation of suitably shaped particles reveals the ability to produce complete, error-free assembly, and leads to the important general observation that reversible growth steps contribute to the high yield. While there are limitations to the MD approach, both computational and conceptual, the results offer a tantalizing hint of the kinds of phenomena that can be explored, and what might be discovered when sufficient resources are brought to bear on a problem.

  11. Using designer confidence and a dynamic Monte Carlo simulation tool to evaluate uncertainty in system models

    E-Print Network [OSTI]

    Lyons, Jeffrey M. (Jeffrey Michael), 1973-

    2000-01-01T23:59:59.000Z

    As the use of distributed engineering models becomes more prevalent, engineers need tools to evaluate the quality of these models and understand how subsystem uncertainty affects predictions of system behavior. This thesis ...

  12. Terascale Simulation Tools and Technologies

    SciTech Connect (OSTI)

    Li, Xiaolin

    2007-03-09T23:59:59.000Z

    We report the development of front tracking method as a simulation tool and technology for the computation on several important SciDAC and SciDAC associated applications. The progress includes the extraction of an independent software library from the front tracking code, conservative front tracking, applications of front tracking to the simulation of fusion pellet injection in a magnetically confined plasma, the study of a fuel injection jet, and the study of fluid chaotic mixing, among other problems.

  13. The Xygra gun simulation tool.

    SciTech Connect (OSTI)

    Garasi, Christopher Joseph; Lamppa, Derek C.; Aubuchon, Matthew S.; Shirley, David Noyes; Robinson, Allen Conrad; Russo, Thomas V.

    2008-12-01T23:59:59.000Z

    Inductive electromagnetic launchers, or coilguns, use discrete solenoidal coils to accelerate a coaxial conductive armature. To date, Sandia has been using an internally developed code, SLINGSHOT, as a point-mass lumped circuit element simulation tool for modeling coilgun behavior for design and verification purposes. This code has shortcomings in terms of accurately modeling gun performance under stressful electromagnetic propulsion environments. To correct for these limitations, it was decided to attempt to closely couple two Sandia simulation codes, Xyce and ALEGRA, to develop a more rigorous simulation capability for demanding launch applications. This report summarizes the modifications made to each respective code and the path forward to completing interfacing between them.

  14. A Smart Home Simulation Tool The Development of a Simulation Tool for Measuring

    E-Print Network [OSTI]

    A Smart Home Simulation Tool The Development of a Simulation Tool for Measuring the Impact of a Smart Grid on a Private Home Michael Nysteen & Henrik Mynderup Kongens Lyngby 2012 IMM-M.Sc.-2012-117 #12;A Smart Home Simulation Tool The Development of a Simulation Tool for Measuring the Impact

  15. Next generation computational tools for extreme-scale simulation of dynamic fracture and fragmentation in three dimensions

    E-Print Network [OSTI]

    Seagraves, Andrew Nathan

    2013-01-01T23:59:59.000Z

    The accurate modeling of dynamic fracture and fragmentation remains one of the most difficult challenges in computational mechanics research. As part of this thesis, a scalable algorithm for modeling dynamic fracture and ...

  16. FPGA-BASED MULTIGRID COMPUTATION FOR MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    FPGA-BASED MULTIGRID COMPUTATION FOR MOLECULAR DYNAMICS SIMULATIONS Yongfeng Gu Martin C. Herbordt serial code. 1. INTRODUCTION Molecular Dynamics simulations (MD) are a fundamental tool for gaining Computer Architecture and Automated Design Laboratory Department of Electrical and Computer Engineering

  17. 2013 IREP Symposium-Bulk Power System Dynamics and Control IX (IREP), August 25-30, 2013, Rethymnon, Greece A Production Simulation Tool for Systems with an Integrated Concentrated Solar

    E-Print Network [OSTI]

    Gross, George

    , Rethymnon, Greece A Production Simulation Tool for Systems with an Integrated Concentrated Solar Plant2013 IREP Symposium-Bulk Power System Dynamics and Control ­IX (IREP), August 25-30, 2013 of the growing interest in effectively harnessing renewable energy resources. The concentrated solar plant (CSP

  18. Advanced Simulation and Optimization Tools for Dynamic Aperture of Non-scaling FFAGs and Accelerators including Modern User Interfaces

    SciTech Connect (OSTI)

    F. Mills, K. Makino, M. Berz, and C. Johnstone

    2010-09-01T23:59:59.000Z

    With the U.S. experimental effort in HEP largely located at laboratories supporting the operations of large, highly specialized accelerators, colliding beam facilities, and detector facilities, the understanding and prediction of high energy particle accelerators becomes critical to the success, overall, of the DOE HEP program. One area in which small businesses can contribute to the ongoing success of the U.S. program in HEP is through innovations in computer techniques and sophistication in the modeling of high-energy accelerators. Accelerator modeling at these facilities is performed by experts with the product generally highly specific and representative only of in-house accelerators or special-interest accelerator problems. Development of new types of accelerators like FFAGs with their wide choices of parameter modifications, complicated fields, and the simultaneous need to efficiently handle very large emittance beams requires the availability of new simulation environments to assure predictability in operation. In this, ease of use and interfaces are critical to realizing a successful model, or optimization of a new design or working parameters of machines. In Phase I, various core modules for the design and analysis of FFAGs were developed and Graphical User Interfaces (GUI) have been investigated instead of the more general yet less easily manageable console-type output COSY provides.

  19. Radiation in molecular dynamic simulations

    SciTech Connect (OSTI)

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M

    2008-10-13T23:59:59.000Z

    Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The new technique passes a key test: it relaxes to a blackbody spectrum for a plasma in local thermodynamic equilibrium. This new tool also provides a method for assessing the accuracy of energy and momentum exchange models in hot dense plasmas. As an example, we simulate the evolution of non-equilibrium electron, ion, and radiation temperatures for a hydrogen plasma using the new molecular dynamics simulation capability.

  20. Intelligent Simulation Tools for Mining Large Scienti c Data Sets 1 Intelligent Simulation Tools for Mining

    E-Print Network [OSTI]

    Bailey-Kellogg, Chris

    Intelligent Simulation Tools for Mining Large Scienti#12;c Data Sets 1 Intelligent Simulation Tools for Mining Large Scienti#12;c Data Sets Feng ZHAO Xerox Palo Alto Research Center 3333 Coyote Hill Road, Palo. Keywords Intelligent simulation, Scienti#12;c data mining, Qualitative reasoning, Reasoning about physical

  1. Revamped Simulation Tool to Power Up Wave Energy Development...

    Energy Savers [EERE]

    Revamped Simulation Tool to Power Up Wave Energy Development Revamped Simulation Tool to Power Up Wave Energy Development May 21, 2015 - 2:40pm Addthis Revamped Simulation Tool to...

  2. Dynamics Within an Organisation: Temporal Specification, Simulation and Evaluation

    E-Print Network [OSTI]

    Treur, Jan

    - 1 - Dynamics Within an Organisation: Temporal Specification, Simulation and Evaluation Catholijn is its dynamics. In this paper different types of specifications of properties of the dynamics within an organisation are introduced. Supporting tools for specification, simulation and analysis of dynamics within

  3. DLFM library tools for large scale dynamic applications.

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

    DLFM library tools for large scale dynamic applications DLFM library tools for large scale dynamic applications Large scale Python and other dynamic applications may spend huge...

  4. Operational Simulation Tools and Long Term Strategic Planning...

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

    Operational Simulation Tools and Long Term Strategic Planning for High Penetrations of PV in the Southeastern U.S. Operational Simulation Tools and Long Term Strategic Planning for...

  5. Development of Design and Simulation Tool for Hybrid Geothermal...

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

    Development of Design and Simulation Tool for Hybrid Geothermal Heat Pump System Development of Design and Simulation Tool for Hybrid Geothermal Heat Pump System This project will...

  6. FPGA Acceleration of Discrete Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Herbordt, Martin

    ' & $ % FPGA Acceleration of Discrete Molecular Dynamics Simulation Joshua Model Thesis submitted UNIVERSITY COLLEGE OF ENGINEERING Thesis FPGA Acceleration of Discrete Molecular Dynamics Simulation Acceleration of Discrete Molecular Dynamics Simulation Joshua Model ABSTRACT Molecular dynamics simulation

  7. Debris Disk Radiative Transfer Simulation Tool (DDS)

    E-Print Network [OSTI]

    S. Wolf; L. A. Hillenbrand

    2005-06-17T23:59:59.000Z

    A WWW interface for the simulation of spectral energy distributions of optically thin dust configurations with an embedded radiative source is presented. The density distribution, radiative source, and dust parameters can be selected either from an internal database or defined by the user. This tool is optimized for studying circumstellar debris disks where large grains are expected to determine the far-infrared through millimeter dust reemission spectral energy distribution. The tool is available at http://aida28.mpia-hd.mpg.de/~swolf/dds

  8. FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    ' & $ % FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS YONGFENG GU Dissertation submitted;BOSTON UNIVERSITY COLLEGE OF ENGINEERING Dissertation FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS DYNAMICS SIMULATIONS (Order No. ) YONGFENG GU Boston University, College of Engineering, 2008 Major

  9. SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments

    E-Print Network [OSTI]

    Griffin, Robert G.

    SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments Mikhail and dynamic information from the spectra. Simulations of solid-state magic angle spinning (MAS) experiments for the simulation of experiments with complex pulse sequences and multi-spin systems in solids, SPINEVO- LUTION

  10. Dynamic simulation of voltage collapses

    SciTech Connect (OSTI)

    Deuse, J.; Stubbe, M. (Tractebel, Brussels (Belgium))

    1993-08-01T23:59:59.000Z

    Most of the time the voltage collapse phenomena are studied by means of computer programs designed for the calculation of steady state conditions. But in the real world, the simultaneous occurrences of losses of synchronism, of AVR dynamics or of transformer tap changes call for a full dynamic simulation of voltage phenomena. The present paper shows some examples of dynamic simulations of voltage phenomena using a new general purpose stability program (EUROSTAG), covering in a continuous way the classical fields of transient, mid-term and long-term stability, and also the quasi steady state conditions of a power system.

  11. Design tools for complex dynamic security systems.

    SciTech Connect (OSTI)

    Byrne, Raymond Harry; Rigdon, James Brian; Rohrer, Brandon Robinson; Laguna, Glenn A.; Robinett, Rush D. III (.; ); Groom, Kenneth Neal; Wilson, David Gerald; Bickerstaff, Robert J.; Harrington, John J.

    2007-01-01T23:59:59.000Z

    The development of tools for complex dynamic security systems is not a straight forward engineering task but, rather, a scientific task where discovery of new scientific principles and math is necessary. For years, scientists have observed complex behavior but have had difficulty understanding it. Prominent examples include: insect colony organization, the stock market, molecular interactions, fractals, and emergent behavior. Engineering such systems will be an even greater challenge. This report explores four tools for engineered complex dynamic security systems: Partially Observable Markov Decision Process, Percolation Theory, Graph Theory, and Exergy/Entropy Theory. Additionally, enabling hardware technology for next generation security systems are described: a 100 node wireless sensor network, unmanned ground vehicle and unmanned aerial vehicle.

  12. Improving Dynamic Load and Generator Response Performance Tools

    E-Print Network [OSTI]

    Lesieutre, Bernard C.

    2005-01-01T23:59:59.000Z

    in dynamic simulations of power systems. Using the PCMDynamic Simulations: The Probabilistic Collocation Method, IEEE Transactions on Power Systems,Dynamic Simulations with Improved Representation of Loads and their Connection to a Power System,

  13. adaptive simulation tool: Topics by E-print Network

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

    tools used for planning, design and supervision of power plants. Using the example of the power plant simulation system Ebsilon Professional, which is established in the market...

  14. Tools and Equipment Modeling for Automobile Interactive Assembling Operating Simulation

    SciTech Connect (OSTI)

    Wu Dianliang; Zhu Hongmin [Shanghai Jiao Tong University (China); Shanghai Key Laboratory of Advance Manufacturing Environment (China)

    2010-05-21T23:59:59.000Z

    Tools and equipment play an important role in the simulation of virtual assembly, especially in the assembly process simulation and plan. Because of variety in function and complexity in structure and manipulation, the simulation of tools and equipments remains to be a challenge for interactive assembly operation. Based on analysis of details and characteristics of interactive operations for automobile assembly, the functional requirement for tools and equipments of automobile assembly is given. Then, a unified modeling method for information expression and function realization of general tools and equipments is represented, and the handling methods of manual, semi-automatic, automatic tools and equipments are discussed. Finally, the application in assembly simulation of rear suspension and front suspension of Roewe 750 automobile is given. The result shows that the modeling and handling methods are applicable in the interactive simulation of various tools and equipments, and can also be used for supporting assembly process planning in virtual environment.

  15. Ice-Floe Simulation Viewer Tool Justin Adams

    E-Print Network [OSTI]

    Peters, Dennis

    Ice-Floe Simulation Viewer Tool Justin Adams Computer Engineering Memorial University St. John's, Newfoundland dpeters@mun.ca Abstract--We are developing software to simulate the be- haviour of sea ice the ability to set up the initial conditions, run the simulation, and display the simulated ice- floe data

  16. Analysis of the influence of tool dynamics in diamond turning

    SciTech Connect (OSTI)

    Fawcett, S.C.; Luttrell, D.E.; Keltie, R.F.

    1988-12-01T23:59:59.000Z

    This report describes the progress in defining the role of machine and interface dynamics on the surface finish in diamond turning. It contains a review of literature from conventional and diamond machining processes relating tool dynamics, material interactions and tool wear to surface finish. Data from experimental measurements of tool/work piece interface dynamics are presented as well as machine dynamics for the DTM at the Center.

  17. Accelerated dynamics simulations of nanotubes.

    SciTech Connect (OSTI)

    Uberuaga, B. P. (Blas Pedro); Stuart, S. J. (Steve J.); Voter, A. F.

    2002-01-01T23:59:59.000Z

    We report on the application of accelerated dynamics techniques to the study of carbon nanotubes. We have used the parallel replica method and temperature accelerated dynamics simulations are currently in progress. In the parallel replica study, we have stretched tubes at a rate significantly lower than that used in previous studies. In these preliminary results, we find that there are qualitative differences in the rupture of the nanotubes at different temperatures. We plan on extending this investigation to include nanotubes of various chiralities. We also plan on exploring unique geometries of nanotubes.

  18. DHARMA: A Tool for Evaluating Dynamic Scheduling Algorithms for Realtime Multiprocessor Systems

    E-Print Network [OSTI]

    Manimaran, Govindarasu

    , and the related issues of fault­tolerance and resource reclaiming. Section 3 reviews the earlier work on dynamic scheduling algorithms. In Section 4, we discuss our dynamic scheduling and reclaiming algorithms. Section 5 simulation results obtained using the tool are presented in Section 6 and in Section 7, some concluding

  19. Improving Dynamic Load and Generator Response PerformanceTools

    SciTech Connect (OSTI)

    Lesieutre, Bernard C.

    2005-11-01T23:59:59.000Z

    This report is a scoping study to examine research opportunities to improve the accuracy of the system dynamic load and generator models, data and performance assessment tools used by CAISO operations engineers and planning engineers, as well as those used by their counterparts at the California utilities, to establish safe operating margins. Model-based simulations are commonly used to assess the impact of credible contingencies in order to determine system operating limits (path ratings, etc.) to ensure compliance with NERC and WECC reliability requirements. Improved models and a better understanding of the impact of uncertainties in these models will increase the reliability of grid operations by allowing operators to more accurately study system voltage problems and the dynamic stability response of the system to disturbances.

  20. Web Based Simulations for Virtual Scientific Experiment: Methodology and Tools

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    . These are the keywords. Web based simulation, Virtual Scientific Experiment, e-learning 1. INTRODUCTION Until now Technology for Enhanced Learning 1 #12;Web Based Simulations for Virtual Scientific Experiment: MethodologyWeb Based Simulations for Virtual Scientific Experiment: Methodology and Tools Giovannina Albano

  1. New Automotive Air Conditioning System Simulation Tool Developed in MATLAB/Simulink

    SciTech Connect (OSTI)

    Kiss, T.; Chaney, L.; Meyer, J.

    2013-07-01T23:59:59.000Z

    Further improvements in vehicle fuel efficiency require accurate evaluation of the vehicle's transient total power requirement. When operated, the air conditioning (A/C) system is the largest auxiliary load on a vehicle; therefore, accurate evaluation of the load it places on the vehicle's engine and/or energy storage system is especially important. Vehicle simulation software, such as 'Autonomie,' has been used by OEMs to evaluate vehicles' energy performance. A transient A/C simulation tool incorporated into vehicle simulation models would also provide a tool for developing more efficient A/C systems through a thorough consideration of the transient A/C system performance. The dynamic system simulation software Matlab/Simulink was used to develop new and more efficient vehicle energy system controls. The various modeling methods used for the new simulation tool are described in detail. Comparison with measured data is provided to demonstrate the validity of the model.

  2. Spin dynamics simulations at AGS

    SciTech Connect (OSTI)

    Huang, H.; MacKay, W.W.; Meot, F.; Roser, T.

    2010-05-23T23:59:59.000Z

    To preserve proton polarization through acceleration, it is important to have a correct model of the process. It has been known that with the insertion of the two helical partial Siberian snakes in the Alternating Gradient Synchrotron (AGS), the MAD model of AGS can not deal with a field map with offset orbit. The stepwise ray-tracing code Zgoubi provides a tool to represent the real electromagnetic fields in the modeling of the optics and spin dynamics for the AGS. Numerical experiments of resonance crossing, including spin dynamics in presence of the snakes and Q-jump, have been performed in AGS lattice models, using Zgoubi. This contribution reports on various results so obtained.

  3. A design tool for reusing integration knowledge in simulation models

    E-Print Network [OSTI]

    Han, Sangmok

    2006-01-01T23:59:59.000Z

    In the academic field of computer-aided product development, the role of the design tool is to support engineering designers to develop and integrate simulation models. Used to save time and costs in product development ...

  4. Loran Coverage Availability Simulation Tool Sherman C. Lo, Stanford University

    E-Print Network [OSTI]

    Stanford University

    of research and development by the Federal Aviation Administration (FAA) Loran technical evaluation team The Loran coverage availability simulation tool (LCAST) was initially created for the 2004 Federal Aviation Administration (FAA) Loran technical evaluation report. The tool incorporated the then current models, algorithms

  5. WINS: Market Simulation Tool for Facilitating Wind Energy Integration

    SciTech Connect (OSTI)

    Shahidehpour, Mohammad [Illinois Institute of Technology

    2012-10-30T23:59:59.000Z

    Integrating 20% or more wind energy into the system and transmitting large sums of wind energy over long distances will require a decision making capability that can handle very large scale power systems with tens of thousands of buses and lines. There is a need to explore innovative analytical and implementation solutions for continuing reliable operations with the most economical integration of additional wind energy in power systems. A number of wind integration solution paths involve the adoption of new operating policies, dynamic scheduling of wind power across interties, pooling integration services, and adopting new transmission scheduling practices. Such practices can be examined by the decision tool developed by this project. This project developed a very efficient decision tool called Wind INtegration Simulator (WINS) and applied WINS to facilitate wind energy integration studies. WINS focused on augmenting the existing power utility capabilities to support collaborative planning, analysis, and wind integration project implementations. WINS also had the capability of simulating energy storage facilities so that feasibility studies of integrated wind energy system applications can be performed for systems with high wind energy penetrations. The development of WINS represents a major expansion of a very efficient decision tool called POwer Market Simulator (POMS), which was developed by IIT and has been used extensively for power system studies for decades. Specifically, WINS provides the following superiorities: (1) An integrated framework is included in WINS for the comprehensive modeling of DC transmission configurations, including mono-pole, bi-pole, tri-pole, back-to-back, and multi-terminal connection, as well as AC/DC converter models including current source converters (CSC) and voltage source converters (VSC). (2) An existing shortcoming of traditional decision tools for wind integration is the limited availability of user interface, i.e., decision results are often text-based demonstrations. WINS includes a powerful visualization tool and user interface capability for transmission analyses, planning, and assessment, which will be of great interest to power market participants, power system planners and operators, and state and federal regulatory entities. (3) WINS can handle extended transmission models for wind integration studies. WINS models include limitations on transmission flow as well as bus voltage for analyzing power system states. The existing decision tools often consider transmission flow constraints (dc power flow) alone which could result in the over-utilization of existing resources when analyzing wind integration. WINS can be used to assist power market participants including transmission companies, independent system operators, power system operators in vertically integrated utilities, wind energy developers, and regulatory agencies to analyze economics, security, and reliability of various options for wind integration including transmission upgrades and the planning of new transmission facilities. WINS can also be used by industry for the offline training of reliability and operation personnel when analyzing wind integration uncertainties, identifying critical spots in power system operation, analyzing power system vulnerabilities, and providing credible decisions for examining operation and planning options for wind integration. Researches in this project on wind integration included (1) Development of WINS; (2) Transmission Congestion Analysis in the Eastern Interconnection; (3) Analysis of 2030 Large-Scale Wind Energy Integration in the Eastern Interconnection; (4) Large-scale Analysis of 2018 Wind Energy Integration in the Eastern U.S. Interconnection. The research resulted in 33 papers, 9 presentations, 9 PhD degrees, 4 MS degrees, and 7 awards. The education activities in this project on wind energy included (1) Wind Energy Training Facility Development; (2) Wind Energy Course Development.

  6. Molecular Dynamics Simulation of the AgCl/Electrolyte Interfacial...

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

    Simulation of the AgClElectrolyte Interfacial Capacity. Molecular Dynamics Simulation of the AgClElectrolyte Interfacial Capacity. Abstract: Molecular dynamics simulation of the...

  7. Molecular dynamics simulation studies of electrolytes andelectrolyte...

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

    Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. es40smith.pdf More Documents & Publications Molecular Dynamics Simulation Studies of...

  8. Molecular dynamics simulation of threshold displacement energies...

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

    experimental estimates in ceramics. Citation: Moreira PA, R Devanathan, J Yu, and WJ Weber.2009."Molecular dynamics simulation of threshold displacement energies in...

  9. Critical Infrastructure Networks and Supernetworks: New Tools for Dynamics,

    E-Print Network [OSTI]

    Nagurney, Anna

    Critical Infrastructure Networks and Supernetworks: New Tools for Dynamics, Network Efficiency Variational Inequalities A New Network Performance/Efficiency Measure with Applications to Critical, Communication, and Energy Networks #12;Components of Common Physical Networks Network System Nodes Links Flows

  10. A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin

    E-Print Network [OSTI]

    Fay, Noah

    A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin Report Prepared by using tools such as tracers to determine groundwater travel times and this dynamic simulation modeling Initiative Fund, Water Sustainability Graduate Fellowship Program 2004/2005 #12;2 Introduction Located

  11. EXTENDED SIMPLE COLORED PETRI NETS: A TOOL FOR PLANT SIMULATION

    E-Print Network [OSTI]

    Coglio, Alessandro

    EXTENDED SIMPLE COLORED PETRI NETS: A TOOL FOR PLANT SIMULATION Antonio Camurri and Alessandro, I­16145 Genova, Italy {music, tokamak}@dist.unige.it ABSTRACT Extended Simple Colored Petri Nets (ESCP­nets) are a new class of High­level Petri Nets conceived as a good trade­off between Petri Nets (P­nets

  12. Services inside the Smart Home A Simulation and Visualization tool

    E-Print Network [OSTI]

    Aiello, Marco

    Services inside the Smart Home A Simulation and Visualization tool Elena Lazovik, Piet den Dulk in developing middleware for smart homes is that this kind of systems are extremely difficult to test and verify on smart homes, that is, homes that contain interactive and pro-active devices, that adapt their behavior

  13. Model Validation with Hybrid Dynamic Simulation

    SciTech Connect (OSTI)

    Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.

    2006-06-18T23:59:59.000Z

    AbstractModel validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation.

  14. UPDATE ON SMALL MODULAR REACTORS DYNAMIC SYSTEM MODELING TOOL Molten Salt Cooled Architecture

    SciTech Connect (OSTI)

    Hale, Richard Edward [ORNL; Cetiner, Sacit M [ORNL; Fugate, David L [ORNL; Qualls, A L [ORNL; Borum, Robert C [ORNL; Chaleff, Ethan S [ORNL; Rogerson, Doug W [ORNL; Batteh, John J [Modelon Corporation; Tiller, Michael M. [Xogeny Corporation

    2014-08-01T23:59:59.000Z

    The Small Modular Reactor (SMR) Dynamic System Modeling Tool project is in the third year of development. The project is designed to support collaborative modeling and study of various advanced SMR (non-light water cooled) concepts, including the use of multiple coupled reactors at a single site. The objective of the project is to provide a common simulation environment and baseline modeling resources to facilitate rapid development of dynamic advanced reactor SMR models, ensure consistency among research products within the Instrumentation, Controls, and Human-Machine Interface (ICHMI) technical area, and leverage cross-cutting capabilities while minimizing duplication of effort. The combined simulation environment and suite of models are identified as the Modular Dynamic SIMulation (MoDSIM) tool. The critical elements of this effort include (1) defining a standardized, common simulation environment that can be applied throughout the program, (2) developing a library of baseline component modules that can be assembled into full plant models using existing geometry and thermal-hydraulic data, (3) defining modeling conventions for interconnecting component models, and (4) establishing user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.

  15. Molecular dynamics simulation and ab intio studies of electrolytes...

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

    Molecular dynamics simulation and ab intio studies of electrolytes and electrolyteelectrode interfaces Molecular dynamics simulation and ab intio studies of electrolytes and...

  16. Atomic detail brownian dynamics simulations of concentrated protein...

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

    detail brownian dynamics simulations of concentrated protein solutions with a mean field treatment of hydrodynamic Atomic detail brownian dynamics simulations of concentrated...

  17. Simulation of Complex Fluids using Dissipative Particle Dynamics

    E-Print Network [OSTI]

    Title: Simulation of Complex Fluids using Dissipative Particle Dynamics Abstract: Dissipative Particle Dynamics (DPD) is a relatively new mesoscopic method...

  18. Molecular Dynamics Simulation of Macromolecules Using Graphics Processing Unit

    E-Print Network [OSTI]

    Ji Xu; Ying Ren; Wei Ge; Xiang Yu; Xiaozhen Yang; Jinghai Li

    2010-01-21T23:59:59.000Z

    Molecular dynamics (MD) simulation is a powerful computational tool to study the behavior of macromolecular systems. But many simulations of this field are limited in spatial or temporal scale by the available computational resource. In recent years, graphics processing unit (GPU) provides unprecedented computational power for scientific applications. Many MD algorithms suit with the multithread nature of GPU. In this paper, MD algorithms for macromolecular systems that run entirely on GPU are presented. Compared to the MD simulation with free software GROMACS on a single CPU core, our codes achieve about 10 times speed-up on a single GPU. For validation, we have performed MD simulations of polymer crystallization on GPU, and the results observed perfectly agree with computations on CPU. Therefore, our single GPU codes have already provided an inexpensive alternative for macromolecular simulations on traditional CPU clusters and they can also be used as a basis to develop parallel GPU programs to further speedup the computations.

  19. SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations

    E-Print Network [OSTI]

    Daniel J. Price

    2007-09-06T23:59:59.000Z

    This paper presents SPLASH, a publicly available interactive visualisation tool for Smoothed Particle Hydrodynamics (SPH) simulations. Visualisation of SPH data is more complicated than for grid-based codes because the data is defined on a set of irregular points and therefore requires a mapping procedure to a two dimensional pixel array. This means that, in practise, many authors simply produce particle plots which offer a rather crude representation of the simulation output. Here we describe the techniques and algorithms which are utilised in SPLASH in order to provide the user with a fast, interactive and meaningful visualisation of one, two and three dimensional SPH results.

  20. RTSTEP regional transportation simulation tool for emergency planning - final report.

    SciTech Connect (OSTI)

    Ley, H.; Sokolov, V.; Hope, M.; Auld, J.; Zhang, K.; Park, Y.; Kang, X. (Energy Systems)

    2012-01-20T23:59:59.000Z

    Large-scale evacuations from major cities during no-notice events - such as chemical or radiological attacks, hazardous material spills, or earthquakes - have an obvious impact on large regions rather than on just the directly affected area. The scope of impact includes the accommodation of emergency evacuation traffic throughout a very large area; the planning of resources to respond appropriately to the needs of the affected population; the placement of medical supplies and decontamination equipment; and the assessment and determination of primary escape routes, as well as routes for incoming emergency responders. Compared to events with advance notice, such as evacuations based on hurricanes approaching an affected area, the response to no-notice events relies exclusively on pre-planning and general regional emergency preparedness. Another unique issue is the lack of a full and immediate understanding of the underlying threats to the population, making it even more essential to gain extensive knowledge of the available resources, the chain of command, and established procedures. Given the size of the area affected, an advanced understanding of the regional transportation systems is essential to help with the planning for such events. The objectives of the work described here (carried out by Argonne National Laboratory) is the development of a multi-modal regional transportation model that allows for the analysis of different evacuation scenarios and emergency response strategies to build a wealth of knowledge that can be used to develop appropriate regional emergency response plans. The focus of this work is on the effects of no-notice evacuations on the regional transportation network, as well as the response of the transportation network to the sudden and unusual demand. The effects are dynamic in nature, with scenarios changing potentially from minute to minute. The response to a radiological or chemical hazard will be based on the time-delayed dispersion of such materials over a large area, with responders trying to mitigate the immediate danger to the population in a variety of ways that may change over time (e.g., in-place evacuation, staged evacuations, and declarations of growing evacuation zones over time). In addition, available resources will be marshaled in unusual ways, such as the repurposing of transit vehicles to support mass evacuations. Thus, any simulation strategy will need to be able to address highly dynamic effects and will need to be able to handle any mode of ground transportation. Depending on the urgency and timeline of the event, emergency responders may also direct evacuees to leave largely on foot, keeping roadways as clear as possible for emergency responders, logistics, mass transport, and law enforcement. This RTSTEP project developed a regional emergency evacuation modeling tool for the Chicago Metropolitan Area that emergency responders can use to pre-plan evacuation strategies and compare different response strategies on the basis of a rather realistic model of the underlying complex transportation system. This approach is a significant improvement over existing response strategies that are largely based on experience gained from small-scale events, anecdotal evidence, and extrapolation to the scale of the assumed emergency. The new tool will thus add to the toolbox available to emergency response planners to help them design appropriate generalized procedures and strategies that lead to an improved outcome when used during an actual event.

  1. Dynamic simulations of arrays of Josephson junctions

    SciTech Connect (OSTI)

    Eikmans, H.; van Himbergen, J.E. (Institute for Theoretical Physics, University of Utrecht, P.O. Box 80.006, 3508 TA Utrecht, The Netherlands (NL))

    1990-05-01T23:59:59.000Z

    First we introduce a very efficient algorithm for dynamic simulations of a wide class of arrays of Josephson junctions with realistic boundaries. With this algorithm one can also represent current-biased arrays with periodic boundaries. Next we present results of extensive simulations of ladder arrays. We evaluate the resistance as a function of magnetic field and find striking differences between different geometries.

  2. DYNAMIC SIMULATION OF PERFORMANCE DEVELOPMENT

    E-Print Network [OSTI]

    Perl, Jürgen

    for scheduling optimal training planes. (a) offline analysis (b) online prediction load profile original) online prediction load profile original performance profile simulated performance profile predicted performance profile Figure 1: Offline load-performance-analysis (a) compared to online performance

  3. Monte Carlo Simulation Tool Installation and Operation Guide

    SciTech Connect (OSTI)

    Aguayo Navarrete, Estanislao; Ankney, Austin S.; Berguson, Timothy J.; Kouzes, Richard T.; Orrell, John L.; Troy, Meredith D.; Wiseman, Clinton G.

    2013-09-02T23:59:59.000Z

    This document provides information on software and procedures for Monte Carlo simulations based on the Geant4 toolkit, the ROOT data analysis software and the CRY cosmic ray library. These tools have been chosen for its application to shield design and activation studies as part of the simulation task for the Majorana Collaboration. This document includes instructions for installation, operation and modification of the simulation code in a high cyber-security computing environment, such as the Pacific Northwest National Laboratory network. It is intended as a living document, and will be periodically updated. It is a starting point for information collection by an experimenter, and is not the definitive source. Users should consult with one of the authors for guidance on how to find the most current information for their needs.

  4. CgWind: A high-order accurate simulation tool for wind turbines and wind farms

    SciTech Connect (OSTI)

    Chand, K K; Henshaw, W D; Lundquist, K A; Singer, M A

    2010-02-22T23:59:59.000Z

    CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.

  5. A Simulation Tool for Analysis of Alternative Paradigms for the New Electricity Business

    E-Print Network [OSTI]

    A Simulation Tool for Analysis of Alternative Paradigms for the New Electricity Business Thomas J preliminary results on the development of a simulation tool to perform this analysis. Since power systems are ultimately governed by the laws of physics, the heart of the tool is a power system simulation engine, valid

  6. A SOFTWARE TOOL TO COMPARE MEASURED AND SIMULATED BUILDING ENERGY PERFORMANCE

    E-Print Network [OSTI]

    LBNL-6184E A SOFTWARE TOOL TO COMPARE MEASURED AND SIMULATED BUILDING ENERGY PERFORMANCE DATA of California. #12;A SOFTWARE TOOL TO COMPARE MEASURED AND SIMULATED BUILDING ENERGY PERFORMANCE DATA Tobias and simulated performance data. In context of this method, we developed a software tool that provides graphing

  7. A Simulation Tool for Combined Rail-Road Transport in Intermodal Terminals

    E-Print Network [OSTI]

    Gambardella, Luca Maria

    A Simulation Tool for Combined Rail-Road Transport in Intermodal Terminals Andrea E. Rizzoli. A simulation tool to model the flow of Intermodal Terminal Units (ITUs) among intermodal terminals is presented. This terminal simulator tool is part of the DGVII EC-funded PLATFORM project. The terminal model is composed

  8. Westinghouse Waste Simulation and Optimization Software Tool - 13493

    SciTech Connect (OSTI)

    Mennicken, Kim [Westinghouse Electric Germany GmbH, Global Waste Management, Dudenstrasse 44, D-68167 Mannheim (Germany)] [Westinghouse Electric Germany GmbH, Global Waste Management, Dudenstrasse 44, D-68167 Mannheim (Germany); Aign, Joerg [Westinghouse Electric Germany GmbH, Global Waste Management, Tarpenring 6, D-22419 Hamburg (Germany)] [Westinghouse Electric Germany GmbH, Global Waste Management, Tarpenring 6, D-22419 Hamburg (Germany)

    2013-07-01T23:59:59.000Z

    Radioactive waste is produced during NPP operation and NPP D and D. Different kinds of waste with different volumes and properties have to be treated. Finding a technically and commercially optimized waste treatment concept is a difficult and time consuming process. The Westinghouse waste simulation and optimization software tool is an approach to study the total life cycle cost of any waste management facility. The tool enables the user of the simulation and optimization software to plan processes and storage buildings and to identify bottlenecks in the overall waste management design before starting detailed planning activities. Furthermore, application of the software enables the user to optimize the number of treatment systems, to determine the minimum design capacity for onsite storage facilities, to identify bottlenecks in the overall design and to identify the most cost-effective treatment paths by maintaining optimal waste treatment technologies. In combination with proven waste treatment equipment and integrated waste management solutions, the waste simulation and optimization software provides reliable qualitative results that lead to an effective planning and minimization of the total project planning risk of any waste management activity. (authors)

  9. Dynamic procedure for filtered gyrokinetic simulations

    SciTech Connect (OSTI)

    Morel, P.; Banon Navarro, A.; Albrecht-Marc, M.; Carati, D. [Statistical and Plasma Physics Laboratory, Universite Libre de Bruxelles, Bruxelles 1050 (Belgium); Merz, F.; Goerler, T.; Jenko, F. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

    2012-01-15T23:59:59.000Z

    Large eddy simulations (LES) of gyrokinetic plasma turbulence are investigated as interesting candidates to decrease the computational cost. A dynamic procedure is implemented in the gene code, allowing for dynamic optimization of the free parameters of the LES models (setting the amplitudes of dissipative terms). Employing such LES methods, one recovers the free energy and heat flux spectra obtained from highly resolved direct numerical simulations. Systematic comparisons are performed for different values of the temperature gradient and magnetic shear, parameters which are of prime importance in ion temperature gradient driven turbulence. Moreover, the degree of anisotropy of the problem, which can vary with parameters, can be adapted dynamically by the method that shows gyrokinetic large eddy simulation to be a serious candidate to reduce numerical cost of gyrokinetic solvers.

  10. Eddy current NDE performance demonstrations using simulation tools

    SciTech Connect (OSTI)

    Maurice, L. [EDF - CEIDRE, 2 rue Ampere, 93206 Saint-Denis Cedex 1 (France); Costan, V.; Guillot, E.; Thomas, P. [EDF - R and D, THEMIS, 1, avenue du General de Gaulle, 92141 Clamart (France)

    2013-01-25T23:59:59.000Z

    To carry out performance demonstrations of the Eddy-Current NDE processes applied on French nuclear power plants, EDF studies the possibility of using simulation tools as an alternative to measurements on steam generator tube mocks-up. This paper focuses on the strategy led by EDF to assess and use code{sub C}armel3D and Civa, on the case of Eddy-Current NDE on wears problem which may appear in the U-shape region of steam generator tubes due to the rubbing of anti-vibration bars.

  11. A visual simulation playground for engineering dynamics

    E-Print Network [OSTI]

    Fong, Donald Brian

    2008-10-10T23:59:59.000Z

    A VISUAL SIMULATION PLAYGROUND FOR ENGINEERING DYNAMICS A Thesis by DONALD BRIAN FONG Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER OF SCIENCE August 2008 Major... Subject: Visualization Sciences A VISUAL SIMULATION PLAYGROUND FOR ENGINEERING DYNAMICS A Thesis by DONALD BRIAN FONG Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER...

  12. Model Validation with Hybrid Dynamic Simulation

    SciTech Connect (OSTI)

    Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.

    2006-06-22T23:59:59.000Z

    AbstractModel validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation. A few methods to define model quality indices have been proposed to quantify model error for model validation criteria development.

  13. A Framework like a tool for specify motivating Collaborative Learning Participatory Simulations

    E-Print Network [OSTI]

    Antunes, Pedro

    1 A Framework like a tool for specify motivating Collaborative Learning Participatory Simulations that collaborative participatory simulations improve teaching and learning, increasing motivation inside. Keywords: Handhelds. Gestures, Sketches. Collaborative Learning. Participatory Simulation. 1. Introduction

  14. Simulations of Particle Dynamics in Magnetorheological Fluids

    E-Print Network [OSTI]

    . Reitich 2 , M.R. Jolly 3 , H.T. Banks 1 , Kazi Ito 1 Abstract We present particle dynamics simulations transformed from a liquid state to that of a Bingham solid upon application of a magnetic (resp., electric as these present a number of advantages over their electric counterparts. These include higher achievable yield

  15. Simulation of plasmaneutral dynamics for radiation cooling

    E-Print Network [OSTI]

    Najmabadi, Farrokh

    the heat flux effectively for future power plants. That is, radiation due to impurities will lower and increase the required pumping speed con- siderably in a power plant. In principle, the plasma energySimulation of plasma­neutral dynamics for radiation cooling Bong Ju Lee , F. Najmabadi Fusion

  16. 2. Unit Operation Dynamic simulation Unit operation

    E-Print Network [OSTI]

    Hong, Deog Ki

    specification . 2.2 Heat transfer equipment Air cooler, cooler/heater, heat exchanger, fired heater LNG multi flow heat exchanger . 2.3 Piping equipment Mixer, tee, pipe, gas pipe, valve, relief valve . 2.4 Rotating equipment Centrifugal compressor or expander, reciprocating compressor pump ,dynamic simulation

  17. Perturbation centrality: a novel centrality measure obtained by the general network dynamics tool, Turbine

    E-Print Network [OSTI]

    Szalay, Kristof Z

    2013-01-01T23:59:59.000Z

    Analysis of network dynamics became increasingly important to understand the mechanisms and consequences of changes in biological systems from macromolecules to cells and organisms. Currently available network dynamics tools are mostly tailored for specific tasks such as calculation of molecular or neural dynamics. Our Turbine software offers a generic framework enabling the simulation of any algorithmically definable dynamics of any network. Turbine is also optimized for handling very large networks in the range of millions of nodes and edges. Using a perturbation transmission model inspired by communicating vessels, here we introduce a novel centrality measure termed as perturbation centrality. Perturbation centrality is the reciprocal of the time needed to dissipate a starting perturbation in the network. Hubs and inter-modular nodes proved to be highly efficient in perturbation propagation. High perturbation centrality nodes of the Met-tRNA synthetase protein structure network were identified as amino aci...

  18. Molecular dynamics simulation and ab intio studies of electrolytes...

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

    DFT calculations on molecular clusters and electrode surfaces, reactive molecular dynamics simulations allowing modeling of SEI formation, and classical molecular dynamics...

  19. Atomistic Simulation of Nafion Membrane: 2. Dynamics of Water...

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

    2. Dynamics of Water Molecules and Hydronium Ions. Atomistic Simulation of Nafion Membrane: 2. Dynamics of Water Molecules and Hydronium Ions. Abstract: We have performed a...

  20. An efficient parallelization scheme for molecular dynamics simulations...

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

    efficient parallelization scheme for molecular dynamics simulations with many-body, flexible, polarizable empirical An efficient parallelization scheme for molecular dynamics...

  1. Molecular dynamics simulations of ion range profiles for heavy...

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

    simulations of ion range profiles for heavy ions in light targets. Molecular dynamics simulations of ion range profiles for heavy ions in light targets. Abstract: The determination...

  2. Molecular Dynamics Simulations of Uranyl and Uranyl Carbonate...

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

    Simulations of Uranyl and Uranyl Carbonate Adsorption at Alumino-silicate Surfaces. Molecular Dynamics Simulations of Uranyl and Uranyl Carbonate Adsorption at Alumino-silicate...

  3. A new report delivers MSHP performance data for use in whole-building simulation tools.

    E-Print Network [OSTI]

    A new report delivers MSHP performance data for use in whole-building simulation tools. Mini performance maps for use in whole-building simulation tools. Most public information on MSHP performance building simulation MSHP models. In the laboratory tests, researchers found that both MSHPs achieved

  4. Project REED (Residential Energy Efficiency Design) is a Web-based building performance simulation tool

    E-Print Network [OSTI]

    -based whole building simulation program that displays graphi- cally the gas and electricity cost of building to deliver powerful build- ing performance simulation tools to precisely targeted audiences. Using interface design, the web has the potential to deliver powerful new building performance simulation tools

  5. A Simulation Tool for Real-time Systems using Environmental Energy Harvesting Maryline CHETTO

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    A Simulation Tool for Real-time Systems using Environmental Energy Harvesting Maryline CHETTO, we present a simulation tool for real-time systems using environmental energy harvesting. Energy. The simulator enables to construct an optimal schedule for any task set, battery capacity and energy source

  6. Activity-based costing simulation as a tool for construction process optimization

    E-Print Network [OSTI]

    Son, Junghye

    1999-01-01T23:59:59.000Z

    to develop the scope of time-cost optimization in this research. Optimization tools, such as neural networks, genetic algorithms, and simulation methods were analyzed to determine an effective tool for the optimization based on the planning and execution...

  7. Molecular Dynamics Simulations on High-Performance Reconfigurable

    E-Print Network [OSTI]

    Herbordt, Martin

    23 Molecular Dynamics Simulations on High-Performance Reconfigurable Computing Systems MATT CHIU. 2010. Molecular dynamics simulations on high performance recon- figurable computing systems. ACM Trans://doi.acm.org/10.1145/1862648.1862653. 1. INTRODUCTION Molecular dynamics simulation (MD) is a

  8. Dynamic Simulation of Electric Machines on FPGA Boards

    E-Print Network [OSTI]

    Zambreno, Joseph A.

    Dynamic Simulation of Electric Machines on FPGA Boards Hao Chen, Song Sun, Dionysios C. Aliprantis USA Abstract--This paper presents the implementation of an induc- tion machine dynamic simulation] devices. Herein, the goal is to implement an entire dynamic simulation of an induction machine on a single

  9. IGCC Dynamic Simulator and Training Center

    SciTech Connect (OSTI)

    Zitney, S.E.; Erbes, M.R. (Enginomix, LLC)

    2006-10-01T23:59:59.000Z

    Integrated Gasification Combined Cycle (IGCC) is emerging as the technology of choice for providing clean, low-cost electricity for the next generation of coal-fired power plants and will play a central role in the development of high-efficiency, zero-emissions power plants such as FutureGen. Several major utilities and developers recently announced plans to build IGCC plants and other major utilities are evaluating IGCCs suitability for base-load capacity additions. This recent surge of attention to IGCC power generation is creating a growing demand for experience with the analysis, operation, and control of commercial-scale IGCC plants. To meet this need, the National Energy Technology Laboratory (NETL) has launched a project to develop a generic, full-scope, IGCC dynamic plant simulator for use in establishing a state-of-the-art simulator training center at West Virginia Universitys (WVU) National Research Center for Coal and Energy (NRCCE). The IGCC Dynamic Simulator & Training (DS&T) Center will be established under the auspices of the Collaboratory for Process & Dynamic Systems Modeling (Collaboratory) organized between NETL, WVU, the University of Pittsburgh, and Carnegie Mellon University.

  10. NREL Developing a Numerical Simulation Tool to Study Hydrokinetic Energy Conversion Devices and Arrays (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-02-01T23:59:59.000Z

    New code will help accelerate design improvements by providing a high-fidelity simulation tool to study power performance, structural loading, and the interactions between devices in arrays.

  11. Method and apparatus for characterizing and enhancing the dynamic performance of machine tools

    DOE Patents [OSTI]

    Barkman, William E; Babelay, Jr., Edwin F

    2013-12-17T23:59:59.000Z

    Disclosed are various systems and methods for assessing and improving the capability of a machine tool. The disclosure applies to machine tools having at least one slide configured to move along a motion axis. Various patterns of dynamic excitation commands are employed to drive the one or more slides, typically involving repetitive short distance displacements. A quantification of a measurable merit of machine tool response to the one or more patterns of dynamic excitation commands is typically derived for the machine tool. Examples of measurable merits of machine tool performance include dynamic one axis positional accuracy of the machine tool, dynamic cross-axis stability of the machine tool, and dynamic multi-axis positional accuracy of the machine tool.

  12. Co-Simulation Tools for Networked Control Systems

    E-Print Network [OSTI]

    Branicky, Michael S.

    Modelica and ns-2. For each tool, we present demonstrative case studies that highlight its capabilities. 1

  13. Brownian Dynamics Simulation of Protein Solutions: Structural and Dynamical Properties

    SciTech Connect (OSTI)

    Mereghetti, Paolo; Gabdoulline, Razif; Wade, Rebecca C.

    2010-12-01T23:59:59.000Z

    The study of solutions of biomacromolecules provides an important basis for understanding the behavior of many fundamental cellular processes, such as protein folding, self-assembly, biochemical reactions, and signal transduction. Here, we describe a Brownian dynamics simulation procedure and its validation for the study of the dynamic and structural properties of protein solutions. In the model used, the proteins are treated as atomically detailed rigid bodies moving in a continuum solvent. The protein-protein interaction forces are described by the sum of electrostatic interaction, electrostatic desolvation, nonpolar desolvation, and soft-core repulsion terms. The linearized Poisson-Boltzmann equation is solved to compute electrostatic terms. Simulations of homogeneous solutions of three different proteins with varying concentrations, pH, and ionic strength were performed. The results were compared to experimental data and theoretical values in terms of long-time self-diffusion coefficients, second virial coefficients, and structure factors. The results agree with the experimental trends and, in many cases, experimental values are reproduced quantitatively. There are no parameters specific to certain protein types in the interaction model, and hence the model should be applicable to the simulation of the behavior of mixtures of macromolecules in cell-like crowded environments.

  14. USING VIDEO FOR ANALYZING DAYLIGHT SIMULATION TOOLS Daniel C. Glaser1

    E-Print Network [OSTI]

    Varela, Carlos

    USING VIDEO FOR ANALYZING DAYLIGHT SIMULATION TOOLS Daniel C. Glaser1 , F. Whitney Smith2 , Barb socio-technical techniques can be employed to analyze video data of people using daylight simulation, a classic daylighting analysis tool; and in the second a lighting professional is asked to use a new data

  15. A PRODUCTION SIMULATION TOOL FOR SYSTEMS WITH INTEGRATED WIND ENERGY RESOURCES

    E-Print Network [OSTI]

    Gross, George

    A PRODUCTION SIMULATION TOOL FOR SYSTEMS WITH INTEGRATED WIND ENERGY RESOURCES BY NICOLAS BENOIT reserves resulting in increased system production costs. Consequently, there is an acute need production simulation tool with the capability to quantify the variable effects of systems with varying wind

  16. Computer simulations to classrooms: tools for change Noah S. Podolefsky, Katherine K. Perkins, & Wendy K. Adams

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    Computer simulations to classrooms: tools for change Noah S. Podolefsky, Katherine K. Perkins-0390 Abstract. This paper situates PhET computer simulations (sims) in a socio-cultural-historical context. Sims learning through exploration. We focus on interactions between three scales of tools: representations

  17. Dynamic Simulators | netl.doe.gov

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEA :Work with Jefferson Lab |NuclearDynamic Simulators NETL

  18. Development of Design and Simulation Tool for Hybrid Geothermal...

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

    * Estimated funding for FY10 is 225,000 - Barriers * Lack of sufficient design and energy analysis tool for hybrid ground source heat pump (HGSHP) systems - Partners * James...

  19. Plasticity of metal wires in torsion: molecular dynamics and dislocation dynamics simulations

    E-Print Network [OSTI]

    Cai, Wei

    Plasticity of metal wires in torsion: molecular dynamics and dislocation dynamics simulations-4040 Abstract The orientation dependent plasticity in metal nanowires is investigated using molecular dynamics metal wires controls the mechanisms of plastic deformation. For wires oriented along 110 , dislocations

  20. Simulating Hamiltonian Dynamics with a Truncated Taylor Series

    E-Print Network [OSTI]

    Berry, Dominic W.

    We describe a simple, efficient method for simulating Hamiltonian dynamics on a quantum computer by approximating the truncated Taylor series of the evolution operator. Our method can simulate the time evolution of a wide ...

  1. Molecular Dynamics Simulation Studies of Electrolytes and Electrolyte...

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

    and is lower than the barrier for opening EC cyclic radical. ReaxFF molecular dynamics simulations show similar barriers in gas and condensed phases for these reactions....

  2. Molecular dynamics simulation and ab intio studies of electrolytes...

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

    Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation es058smith2011o.pdf More Documents & Publications Molecular Dynamics Simulation Studies of...

  3. Games, Role-Playing, Tools and Models as a Learning Process to Simulate Groundwater Management Negotiation

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Games, Role-Playing, Tools and Models as a Learning Process to Simulate Groundwater Management in answering this question at a local level. A negotiation support simulator for a regional project is proposed which includes the numerous actors involved in water resource management projects. This simulator

  4. Abaqus Simulations of Rock Response to Dynamic Loading

    SciTech Connect (OSTI)

    Steedman, David W. [Los Alamos National Laboratory; Coblentz, David [Los Alamos National Laboratory

    2012-08-15T23:59:59.000Z

    The LANL Geodynamics Team has been applying Abaqus modeling to achieve increasingly complex simulations. Advancements in Abaqus model building and simulation tools allows this progress. We use Lab-developed constitutive models, the fully coupled CEL Abaqus and general contact to simulate response of realistic sites to explosively driven shock.

  5. ASTROPHYSICAL FLUID DYNAMICS VIA DIRECT STATISTICAL SIMULATION

    SciTech Connect (OSTI)

    Tobias, S. M. [Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom); Dagon, K.; Marston, J. B., E-mail: smt@maths.leeds.ac.uk [Department of Physics, Brown University, Providence, RI 02912-1843 (United States)

    2011-02-01T23:59:59.000Z

    In this paper, we introduce the concept of direct statistical simulation for astrophysical flows. This technique may be appropriate for problems in astrophysical fluids where the instantaneous dynamics of the flows are of secondary importance to their statistical properties. We give examples of such problems including mixing and transport in planets, stars, and disks. The method is described for a general set of evolution equations, before we consider the specific case of a spectral method optimized for problems on a spherical surface. The method is illustrated for the simplest non-trivial example of hydrodynamics and magnetohydrodynamics on a rotating spherical surface. We then discuss possible extensions of the method both in terms of computational methods and the range of astrophysical problems that are of interest.

  6. CADS:Cantera Aerosol Dynamics Simulator.

    SciTech Connect (OSTI)

    Moffat, Harry K.

    2007-07-01T23:59:59.000Z

    This manual describes a library for aerosol kinetics and transport, called CADS (Cantera Aerosol Dynamics Simulator), which employs a section-based approach for describing the particle size distributions. CADS is based upon Cantera, a set of C++ libraries and applications that handles gas phase species transport and reactions. The method uses a discontinuous Galerkin formulation to represent the particle distributions within each section and to solve for changes to the aerosol particle distributions due to condensation, coagulation, and nucleation processes. CADS conserves particles, elements, and total enthalpy up to numerical round-off error, in all of its formulations. Both 0-D time dependent and 1-D steady state applications (an opposing-flow flame application) have been developed with CADS, with the initial emphasis on developing fundamental mechanisms for soot formation within fires. This report also describes the 0-D application, TDcads, which models a time-dependent perfectly stirred reactor.

  7. Study of residential dehumidifiers results in practical performance curves for use in whole-building simulation tools.

    E-Print Network [OSTI]

    -building simulation tools. Dehumidifiers remove moisture from a home's indoor environment, thereby increasing occupant dehumidifier to be simulated in whole-building analysis tools. NREL researchers also defined a new, generalized determine moisture removal capacities and efficiencies.Whole-building simulation tool performance curves

  8. Sensitivity, Approximation and Uncertainty in Power System Dynamic Simulation

    E-Print Network [OSTI]

    1 Sensitivity, Approximation and Uncertainty in Power System Dynamic Simulation Ian A. Hiskens, Fellow, IEEE Jassim Alseddiqui Student Member, IEEE Abstract-- Parameters of power system models the influence of uncertainty in simulations of power system dynamic behaviour. It is shown that trajectory

  9. A Qualitative Simulation Approach for Fuzzy Dynamical Models

    E-Print Network [OSTI]

    Bontempi, Gianluca

    .g., a nuclear power plant in unexpected emergency situations) or because if does not yet exist (eA Qualitative Simulation Approach for Fuzzy Dynamical Models ANDREA BONARINI and GIANLUCA BONTEMPI Politecnico di Milano This article deal with simulation of approximate models of dynamic systems. We propose

  10. Fast Dynamic Simulation-Based Small Signal Stability Assessment and Control

    SciTech Connect (OSTI)

    Acharya, Naresh; Baone, Chaitanya; Veda, Santosh; Dai, Jing; Chaudhuri, Nilanjan; Leonardi, Bruno; Sanches-Gasca, Juan; Diao, Ruisheng; Wu, Di; Huang, Zhenyu; Zhang, Yu; Jin, Shuangshuang; Zheng, Bin; Chen, Yousu

    2014-12-31T23:59:59.000Z

    Power grid planning and operation decisions are made based on simulation of the dynamic behavior of the system. Enabling substantial energy savings while increasing the reliability of the aging North American power grid through improved utilization of existing transmission assets hinges on the adoption of wide-area measurement systems (WAMS) for power system stabilization. However, adoption of WAMS alone will not suffice if the power system is to reach its full entitlement in stability and reliability. It is necessary to enhance predictability with "faster than real-time" dynamic simulations that will enable the dynamic stability margins, proactive real-time control, and improve grid resiliency to fast time-scale phenomena such as cascading network failures. Present-day dynamic simulations are performed only during offline planning studies, considering only worst case conditions such as summer peak, winter peak days, etc. With widespread deployment of renewable generation, controllable loads, energy storage devices and plug-in hybrid electric vehicles expected in the near future and greater integration of cyber infrastructure (communications, computation and control), monitoring and controlling the dynamic performance of the grid in real-time would become increasingly important. The state-of-the-art dynamic simulation tools have limited computational speed and are not suitable for real-time applications, given the large set of contingency conditions to be evaluated. These tools are optimized for best performance of single-processor computers, but the simulation is still several times slower than real-time due to its computational complexity. With recent significant advances in numerical methods and computational hardware, the expectations have been rising towards more efficient and faster techniques to be implemented in power system simulators. This is a natural expectation, given that the core solution algorithms of most commercial simulators were developed decades ago, when High Performance Computing (HPC) resources were not commonly available.

  11. An investigation of soil-tool interaction theories as they apply to a Lunar soil simulant

    E-Print Network [OSTI]

    Willman, Brian Michael

    1992-01-01T23:59:59.000Z

    AN INVESTIGATION OF SOIL - TOOL INTERACTION THEORIES AS THEY APPLY TO A LUNAR SOIL SIMULANT A Thesis by BRIAN MICHAEL WILLMAN Submitted to the Office of Graduate Studies of Texas AkM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1992 Major Subject: Civil Engineering AN INVESTIGATION OF SOIL - TOOL INTERACTION THEORIES AS THEY APPLY TO A LUNAR SOIL SIMULANT A Thesis by BRIAN MICHAEL WILLMAN Submitted to Texas A&M University in partial...

  12. Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations, and two dimensional IR spectroscopy

    E-Print Network [OSTI]

    Fayer, Michael D.

    Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations the nature and dynamics of the phenol-benzene complex in the mixed solvent, benzene/CCl4. Under thermal used for the phenol-benzene interaction in the MD simulations is in good accord with the highest level

  13. Nonequilibrium candidate Monte Carlo: A new tool for efficient equilibrium simulation

    SciTech Connect (OSTI)

    Nilmeier, Jerome P.; Crooks, Gavin E.; Minh, David D. L.; Chodera, John D.

    2011-11-08T23:59:59.000Z

    Metropolis Monte Carlo simulation is a powerful tool for studying the equilibrium properties of matter. In complex condensed-phase systems, however, it is difficult to design Monte Carlo moves with high acceptance probabilities that also rapidly sample uncorrelated configurations. Here, we introduce a new class of moves based on nonequilibrium dynamics: candidate configurations are generated through a finite-time process in which a system is actively driven out of equilibrium, and accepted with criteria that preserve the equilibrium distribution. The acceptance rule is similar to the Metropolis acceptance probability, but related to the nonequilibrium work rather than the instantaneous energy difference. Our method is applicable to sampling from both a single thermodynamic state or a mixture of thermodynamic states, and allows both coordinates and thermodynamic parameters to be driven in nonequilibrium proposals. While generating finite-time switching trajectories incurs an additional cost, driving some degrees of freedom while allowing others to evolve naturally can lead to large enhancements in acceptance probabilities, greatly reducing structural correlation times. Using nonequilibrium driven processes vastly expands the repertoire of useful Monte Carlo proposals in simulations of dense solvated systems.

  14. Modelling and simulation of multidisciplinary dynamic systems Lead: A. Fakri.

    E-Print Network [OSTI]

    Baudoin, Geneviève

    Modelling and simulation of multidisciplinary dynamic systems Lead: A. Fakri. Permanent members: P. Integration of various engineering disciplines and the consideration of the dynamic control need a concurrent suited for the energy exchanges to study multidisciplinary dynamic engineering systems modelling. Our

  15. Simulation Algorithms in Vehicle System Dynamics MARTIN ARNOLD

    E-Print Network [OSTI]

    , hydraulic and other system components [1, 2], see also [3] for a summary of recent developments and [4 an overview on classical and more advanced simu- lation algorithms in vehicle system dynamics that are closelySimulation Algorithms in Vehicle System Dynamics MARTIN ARNOLD SUMMARY Multi-body dynamics may

  16. 9/28/98 9:58:58 am, Journal of Non-Crystalline Solids MOLECULAR DYNAMICS SIMULATION OF VITREOUS SILICA STRUCTURES

    E-Print Network [OSTI]

    Goddard III, William A.

    Dynamics (MD) techniques to simulate glass structures has become a valuable tool for gaining insight1 9/28/98 9:58:58 am, Journal of Non-Crystalline Solids MOLECULAR DYNAMICS SIMULATION OF VITREOUS SILICA STRUCTURES Norman T. Huff*, Owens Corning Science and Technology Center, 2790 Columbus Road

  17. Kinetic simulations of plasmoid chain dynamics

    SciTech Connect (OSTI)

    Markidis, S. [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)] [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden); Henri, P. [Universit de Nice Sophia Antipolis, CNRS, Observatoire de la Cte d'Azur, Nice (France)] [Universit de Nice Sophia Antipolis, CNRS, Observatoire de la Cte d'Azur, Nice (France); Lapenta, G. [Centrum voor Plasma-Astrofysica, Department Wiskunde, Katholieke Universiteit Leuven, Leuven (Belgium)] [Centrum voor Plasma-Astrofysica, Department Wiskunde, Katholieke Universiteit Leuven, Leuven (Belgium); Divin, A. [Swedish Institute of Space Physics, Uppsala (Sweden)] [Swedish Institute of Space Physics, Uppsala (Sweden); Goldman, M.; Newman, D. [Department of Physics and CIPS, University of Colorado, Boulder 80309-0390 (United States)] [Department of Physics and CIPS, University of Colorado, Boulder 80309-0390 (United States); Laure, E. [PDC and High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)] [PDC and High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)

    2013-08-15T23:59:59.000Z

    The dynamics of a plasmoid chain is studied with three dimensional Particle-in-Cell simulations. The evolution of the system with and without a uniform guide field, whose strength is 1/3 the asymptotic magnetic field, is investigated. The plasmoid chain forms by spontaneous magnetic reconnection: the tearing instability rapidly disrupts the initial current sheet generating several small-scale plasmoids that rapidly grow in size coalescing and kinking. The plasmoid kink is mainly driven by the coalescence process. It is found that the presence of guide field strongly influences the evolution of the plasmoid chain. Without a guide field, a main reconnection site dominates and smaller reconnection regions are included in larger ones, leading to an hierarchical structure of the plasmoid-dominated current sheet. On the contrary in presence of a guide field, plasmoids have approximately the same size and the hierarchical structure does not emerge, a strong core magnetic field develops in the center of the plasmoid in the direction of the existing guide field, and bump-on-tail instability, leading to the formation of electron holes, is detected in proximity of the plasmoids.

  18. Annual Report 1999 Environmental Dynamics and Simulation

    SciTech Connect (OSTI)

    NS Foster-Mills

    2000-06-28T23:59:59.000Z

    This annual report describes selected 1999 research accomplishments for the Environmental Dynamics and Simulation (ED and S) directorate, one of six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). These accomplishments are representative of the different lines of research underway in the ED and S directorate. EMSL is one of US Department of Energy's (DOE) national scientific user facilities and is the centerpiece of DOE's commitment to providing world-class experimental, theoretical, and computational capabilities for solving the nation's environmental problems. Capabilities in the EMSL include over 100 major instrument systems for use by the resident research staff, their collaborators, and users of the EMSL. These capabilities are used to address the fundamental science that will be the basis for finding solutions to national environmental issues such as cleaning up contamianted areas at DOE sites across the country and developing green technologies that will reduce or eliminate future pollution production. The capabilities are also used to further the understanding of global climate change and environmental issues relevant to energy production and use and health effects resulting from exposure to contaminated environments.

  19. Development of simulation tools for virus shell assembly. Final report

    SciTech Connect (OSTI)

    Berger, Bonnie

    2001-01-05T23:59:59.000Z

    Prof. Berger's major areas of research have been in applying computational and mathematical techniques to problems in biology, and more specifically to problems in protein folding and genomics. Significant progress has been made in the following areas relating to virus shell assembly: development has been progressing on a second-generation self-assembly simulator which provides a more versatile and physically realistic model of assembly; simulations are being developed and applied to a variety of problems in virus assembly; and collaborative efforts have continued with experimental biologists to verify and inspire the local rules theory and the simulator. The group has also worked on applications of the techniques developed here to other self-assembling structures in the material and biological sciences. Some of this work has been conducted in conjunction with Dr. Sorin Istrail when he was at Sandia National Labs.

  20. HYBRID GROUND SOURCE HEAT PUMP SYSTEM SIMULATION USING VISUAL MODELING TOOL FOR HVACSIM+

    E-Print Network [OSTI]

    HYBRID GROUND SOURCE HEAT PUMP SYSTEM SIMULATION USING VISUAL MODELING TOOL FOR HVACSIM+ M.H. Khan, 74078, USA ABSTRACT This paper presents a simulation of a hybrid ground source heat pump system, performed using a new graphical user interface for HVACSIM+. Hybrid ground source heat pump systems

  1. SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments

    E-Print Network [OSTI]

    Griffin, Robert G.

    SPINEVOLUTION: A powerful tool for the simulation of solid and liquid state NMR experiments Mikhail. Simulations of solid-state magic angle spinning (MAS) experiments can be particularly demanding both with complex pulse sequences and multi-spin systems in solids, SPINEVO- LUTION is a versatile and easy to use

  2. DHARMA: A Tool for Evaluating Dynamic Scheduling Algorithms for Realtime Multiprocessor Systems

    E-Print Network [OSTI]

    Manimaran, Govindarasu

    ­tolerance and resource reclaiming. Section 3 reviews the earlier work on dynamic scheduling algorithms. In Section 4, we discuss our dynamic scheduling and reclaiming algorithms. Section 5 discusses the software architectureDHARMA: A Tool for Evaluating Dynamic Scheduling Algorithms for Real­time Multiprocessor Systems G

  3. NREL: Dynamic Maps, GIS Data, and Analysis Tools - Unsubscribe

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

    GIS Renewable Energy Technical Potential Maps Data Resources Data Visualization & Geospatial Tools Geospatial Team Publications Mailing List Contact Us Did you find what you...

  4. NREL Evaluates the Thermal Performance of Uninsulated Walls to Improve the Accuracy of Building Energy Simulation Tools (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-01-01T23:59:59.000Z

    This technical highlight describes NREL research to develop models of uninsulated wall assemblies that help to improve the accuracy of building energy simulation tools when modeling potential energy savings in older homes. Researchers at the National Renewable Energy Laboratory (NREL) have developed models for evaluating the thermal performance of walls in existing homes that will improve the accuracy of building energy simulation tools when predicting potential energy savings of existing homes. Uninsulated walls are typical in older homes where the wall cavities were not insulated during construction or where the insulating material has settled. Accurate calculation of heat transfer through building enclosures will help determine the benefit of energy efficiency upgrades in order to reduce energy consumption in older American homes. NREL performed detailed computational fluid dynamics (CFD) analysis to quantify the energy loss/gain through the walls and to visualize different airflow regimes within the uninsulated cavities. The effects of ambient outdoor temperature, radiative properties of building materials, and insulation level were investigated. The study showed that multi-dimensional airflows occur in walls with uninsulated cavities and that the thermal resistance is a function of the outdoor temperature - an effect not accounted for in existing building energy simulation tools. The study quantified the difference between CFD prediction and the approach currently used in building energy simulation tools over a wide range of conditions. For example, researchers found that CFD predicted lower heating loads and slightly higher cooling loads. Implementation of CFD results into building energy simulation tools such as DOE2 and EnergyPlus will likely reduce the predicted heating load of homes. Researchers also determined that a small air gap in a partially insulated cavity can lead to a significant reduction in thermal resistance. For instance, a 4-in. tall air gap (Figure 1a) led to a 15% reduction in resistance. Similarly, a 2-ft tall air gap (Figure 1c) led to 54% reduction in thermal resistance. NREL researchers plan to extend this study to include additional wall configurations, and also to evaluate the performance of attic spaces with different insulation levels. NREL's objective is to address each potential issue that leads to inaccuracies in building energy simulation tools to improve the predictions.

  5. Development of a dynamic simulator for a natural gas combined cycle (NGCC) power plant with post-combustion carbon capture

    SciTech Connect (OSTI)

    Liese, E.; Zitney, S.

    2012-01-01T23:59:59.000Z

    The AVESTAR Center located at the U.S. Department of Energys National Energy Technology Laboratory and West Virginia University is a world-class research and training environment dedicated to using dynamic process simulation as a tool for advancing the safe, efficient and reliable operation of clean energy plants with CO{sub 2} capture. The AVESTAR Center was launched with a high-fidelity dynamic simulator for an Integrated Gasification Combined Cycle (IGCC) power plant with pre-combustion carbon capture. The IGCC dynamic simulator offers full-scope Operator Training Simulator (OTS) Human Machine Interface (HMI) graphics for realistic, real-time control room operation and is integrated with a 3D virtual Immersive Training Simulator (ITS), thus allowing joint control room and field operator training. The IGCC OTS/ITS solution combines a gasification with CO{sub 2} capture process simulator with a combined cycle power simulator into a single high-performance dynamic simulation framework. This presentation will describe progress on the development of a natural gas combined cycle (NGCC) dynamic simulator based on the syngas-fired combined cycle portion of AVESTARs IGCC dynamic simulator. The 574 MW gross NGCC power plant design consisting of two advanced F-class gas turbines, two heat recovery steam generators (HRSGs), and a steam turbine in a multi-shaft 2x2x1 configuration will be reviewed. Plans for integrating a post-combustion carbon capture system will also be discussed.

  6. Molecular Dynamics Simulation Studies of Electrolytes andElectrolyte...

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

    Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. es058smith2010p.pdf More Documents & Publications Molecular dynamics simulation and ab intio...

  7. DYNAMIC SIMULATION OF THE TEMPORAL RESPONSE OF MICROSTRUCTURE FORMATION IN

    E-Print Network [OSTI]

    DYNAMIC SIMULATION OF THE TEMPORAL RESPONSE OF MICROSTRUCTURE FORMATION IN MAGNETORHEOLOGICAL in that the dielectric response of an ER fluid is studied in response to an electrical stimulus. These studies of MR

  8. Ab Initio Molecular Dynamics Simulations of Low-Energy Recoil...

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

    than the ions on lattice sites in perfect MO2. Citation: Xiao HY, Y Zhang, and WJ Weber.2012."Ab Initio Molecular Dynamics Simulations of Low-Energy Recoil Eventsin ThO2,...

  9. Molecular Dynamics Simulations of Heat Transfer In Nanoscale Liquid Films

    E-Print Network [OSTI]

    Kim, Bo Hung

    2010-07-14T23:59:59.000Z

    Molecular Dynamics (MD) simulations of nano-scale flows typically utilize fixed lattice crystal interactions between the fluid and stationary wall molecules. This approach cannot properly model thermal interactions at the wall-fluid interface...

  10. Simulation of the dynamic response of a damped taught string

    E-Print Network [OSTI]

    Favennec, Herv

    2007-01-01T23:59:59.000Z

    Marine pipeline are facing new issues involved by the increase of the depth of exploited oil and gas reservoirs. This thesis discusses the changes in the dynamic behavior of marine pipelines and proposes a simple simulation ...

  11. Organizational capabilities assessment: a dynamic methodology, methods and a tool for supporting

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    Organizational capabilities assessment: a dynamic methodology, methods and a tool for supporting organizational diagnosis Philippe RAUFFET, Catherine DA CUNHA, Alain BERNARD IRCCyN laboratory Ecole Centrale in organizations in order to develop collective competencies, called also organizational capabilities, around

  12. Field Test Best Practices: A Dynamic Web Tool for Practical Guidance

    Energy Savers [EERE]

    b y t he A lliance f or S ustainable E nergy, L LC. Field Test Best Practices A dynamic web tool for practical guidance BA Webinar Lieko Earle & Bethany Sparn March 18, 2015...

  13. Molecular simulation as a tool for studying lignin

    SciTech Connect (OSTI)

    Sangha, Amandeep K [ORNL; Petridis, Loukas [ORNL; Smith, Jeremy C [ORNL; Ziebell, Angela L [ORNL; Parks, Jerry M [ORNL

    2012-01-01T23:59:59.000Z

    Lignocellulosic biomass provides a sustainable source of sugars for biofuel and biomaterial production. However, biomass resistance to degradation imposes difficulties for economical conversion of plant carbohydrates to fermentable sugars. One of the key contributors to recalcitrance is lignin. Understanding the properties of lignin macromolecules in the cell wall matrix is useful for manipulating biomass structure to generate more easily degradable biomass. Along with experimental techniques such as 2D-NMR and mass spectrometry, computational techniques can be useful for characterizing the structural and energetic properties of the biomass assembly and its individual constituents. Here, we provide a brief introduction to lignin, review some of the recent, relevant scientific literature, and give our perspectives on the role of molecular simulation in understanding lignin structure.

  14. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    SciTech Connect (OSTI)

    Rong Fan

    2006-08-09T23:59:59.000Z

    Fluidized beds (FB) reactors are widely used in the polymerization industry due to their superior heat- and mass-transfer characteristics. Nevertheless, problems associated with local overheating of polymer particles and excessive agglomeration leading to FB reactors defluidization still persist and limit the range of operating temperatures that can be safely achieved in plant-scale reactors. Many people have been worked on the modeling of FB polymerization reactors, and quite a few models are available in the open literature, such as the well-mixed model developed by McAuley, Talbot, and Harris (1994), the constant bubble size model (Choi and Ray, 1985) and the heterogeneous three phase model (Fernandes and Lona, 2002). Most these research works focus on the kinetic aspects, but from industrial viewpoint, the behavior of FB reactors should be modeled by considering the particle and fluid dynamics in the reactor. Computational fluid dynamics (CFD) is a powerful tool for understanding the effect of fluid dynamics on chemical reactor performance. For single-phase flows, CFD models for turbulent reacting flows are now well understood and routinely applied to investigate complex flows with detailed chemistry. For multiphase flows, the state-of-the-art in CFD models is changing rapidly and it is now possible to predict reasonably well the flow characteristics of gas-solid FB reactors with mono-dispersed, non-cohesive solids. This thesis is organized into seven chapters. In Chapter 2, an overview of fluidized bed polymerization reactors is given, and a simplified two-site kinetic mechanism are discussed. Some basic theories used in our work are given in detail in Chapter 3. First, the governing equations and other constitutive equations for the multi-fluid model are summarized, and the kinetic theory for describing the solid stress tensor is discussed. The detailed derivation of DQMOM for the population balance equation is given as the second section. In this section, monovariate population balance, bivariate population balance, aggregation and breakage equation and DQMOM-Multi-Fluid model are described. In the last section of Chapter 3, numerical methods involved in the multi-fluid model and time-splitting method are presented. Chapter 4 is based on a paper about application of DQMOM to polydisperse gas-solid fluidized beds. Results for a constant aggregation and breakage kernel and a kernel developed from kinetic theory are shown. The effect of the aggregation success factor and the fragment distribution function are investigated. Chapter 5 shows the work on validation of mixing and segregation phenomena in gas-solid fluidized beds with a binary mixture or a continuous size distribution. The simulation results are compared with available experiment data and discrete-particle simulation. Chapter 6 presents the project with Univation Technologies on CFD simulation of a Polyethylene pilot-scale FB reactor, The fluid dynamics, mass/heat transfer and particle size distribution are investigated through CFD simulation and validated with available experimental data. The conclusions of this study and future work are discussed in Chapter 7.

  15. Using Product Specific Simulation Models in a Tool for Manual Commissioning of Air Handling Units

    E-Print Network [OSTI]

    Eriksson, J.

    2003-01-01T23:59:59.000Z

    USING PRODUCT SPECIFIC SIMULATION MODELS IN A TOOL FOR MANUAL COMMISSIONING OF AIR HANDLING UNITS J?RGEN ERIKSSON ?F-INSTALLATION AB GOTHENBURG, SWEDEN ABSTRACT This short paper describes an outline of a tool for manual commissioning.... Cetetherm IQHeat. Cetetherm. Ronneby. Sweden. 3. Portland Energy Conservation Inc. Methods for automated and continuous commissioning of build- ings. Air-Conditioning and refrigeraration technol- ogy institute, Arlington, Virginia. 4. T. Haasl, D...

  16. Synthesis Tools for Structural Dynamics and Partitioned Analysis of Coupled Systems

    E-Print Network [OSTI]

    Felippa, Carlos A.

    . Synthesis Tools for Structural Dynamics and Partitioned Analysis of Coupled Systems C. A. Felippa and K. C. Park Department of Aerospace Engineering Sciences and Center for Aerospace Structures and K. C. Park domain. It can only show that a model works. A "bridging" tool between human analytics

  17. A Taxonomy of Buffer Overflows for Evaluating Static and Dynamic Software Testing Tools*

    E-Print Network [OSTI]

    A Taxonomy of Buffer Overflows for Evaluating Static and Dynamic Software Testing Tools* Kendra Phone: 7819812711 Email: LIPPMANN@LL.MIT.EDU ABSTRACT A taxonomy that uses 22 attributes detection tools. Attributes in the taxonomy include the buffer location (e.g. stack, heap, data

  18. Accelerated molecular dynamics and equation-free methods for simulating diffusion in solids.

    SciTech Connect (OSTI)

    Deng, Jie; Zimmerman, Jonathan A.; Thompson, Aidan Patrick; Brown, William Michael (Oak Ridge National Laboratories, Oak Ridge, TN); Plimpton, Steven James; Zhou, Xiao Wang; Wagner, Gregory John; Erickson, Lindsay Crowl

    2011-09-01T23:59:59.000Z

    Many of the most important and hardest-to-solve problems related to the synthesis, performance, and aging of materials involve diffusion through the material or along surfaces and interfaces. These diffusion processes are driven by motions at the atomic scale, but traditional atomistic simulation methods such as molecular dynamics are limited to very short timescales on the order of the atomic vibration period (less than a picosecond), while macroscale diffusion takes place over timescales many orders of magnitude larger. We have completed an LDRD project with the goal of developing and implementing new simulation tools to overcome this timescale problem. In particular, we have focused on two main classes of methods: accelerated molecular dynamics methods that seek to extend the timescale attainable in atomistic simulations, and so-called 'equation-free' methods that combine a fine scale atomistic description of a system with a slower, coarse scale description in order to project the system forward over long times.

  19. Modeling ramp compression experiments using large-scale molecular dynamics simulation.

    SciTech Connect (OSTI)

    Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)

    2011-10-01T23:59:59.000Z

    Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.

  20. Learning Curve: A Simulation-based Approach to Dynamic Pricing

    E-Print Network [OSTI]

    Greenwald, Amy

    horizon. In this article, we refer to this type of changing of prices over time as dynamic pricing. Cost markets, the costs associated with making frequent, instantaneous price changes are greatly diminished [2Learning Curve: A Simulation-based Approach to Dynamic Pricing Joan Morris DiMicco, Amy Greenwald

  1. A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling and Control L. Nehaoua and dynamics modeling will be presented. Some results are shown, validating the actutation requirements and platform control. 1. INTRODUCTION Road safety has become a major political and economical issue. While all

  2. Fast Thermal Simulation for Architecture Level Dynamic Thermal Management

    E-Print Network [OSTI]

    Tan, Sheldon X.-D.

    Fast Thermal Simulation for Architecture Level Dynamic Thermal Management Pu Liu, Zhenyu Qi, Hang Li, Lingling Jin, Wei Wu, Sheldon X.-D. Tan, Jun Yang Department of Electrical Engineering temperature by dynamic thermal managements becomes necessary. This paper proposes a novel approach

  3. Dynamic Spherical Volumetric Simplex Splines with Applications in Biomedical Simulation

    E-Print Network [OSTI]

    Hua, Jing

    Dynamic Spherical Volumetric Simplex Splines with Applications in Biomedical Simulation Yunhao Tan computational framework based on dy- namic spherical volumetric simplex splines for simulation of genus- zero to reconstruct the high-fidelity digi- tal model of a real-world object with spherical volumetric simplex splines

  4. aerosol dynamics simulator: Topics by E-print Network

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

    aerosol dynamics simulator First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 5, 79658026, 2005 Simulating...

  5. Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS

    E-Print Network [OSTI]

    Shapiro, Benjamin

    ABSTRACT Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS OF ELECTRO an algorithm to steer indi- vidual particles inside the EWOD system by control of actuators already present number of actuators available in the EWOD system. #12;MODELING, SIMULATING, AND CONTROLLING THE FLUID

  6. Modelling and Dynamic Simulation for Process Control

    E-Print Network [OSTI]

    Skogestad, Sigurd

    principles for model development are outlined, and these principles are applied to a simple ash tank (which. In this paper we consider dynamic process models obtained using fundamental principles (eg. based reactor, a simple trend analysis using temperature measurements may be sucient. Dynamic models

  7. Reweighting QCD simulations with dynamical overlap fermions

    E-Print Network [OSTI]

    Thomas DeGrand

    2008-10-03T23:59:59.000Z

    I apply a recently developed algorithm for reweighting simulations of lattice QCD from one quark mass to another to simulations performed with overlap fermions in the epsilon regime. I test it by computing the condensate from distributions of the low lying eigenvalues of the Dirac operator. Results seem favorable.

  8. N-body simulations in modified Newtonian dynamics

    E-Print Network [OSTI]

    Carlo Nipoti; Pasquale Londrillo; Luca Ciotti

    2008-11-18T23:59:59.000Z

    We describe some results obtained with N-MODY, a code for N-body simulations of collisionless stellar systems in modified Newtonian dynamics (MOND). We found that a few fundamental dynamical processes are profoundly different in MOND and in Newtonian gravity with dark matter. In particular, violent relaxation, phase mixing and galaxy merging take significantly longer in MOND than in Newtonian gravity, while dynamical friction is more effective in a MOND system than in an equivalent Newtonian system with dark matter.

  9. Plasticity of metal wires in torsion: Molecular dynamics and dislocation dynamics simulations

    E-Print Network [OSTI]

    Cai, Wei

    Plasticity of metal wires in torsion: Molecular dynamics and dislocation dynamics simulations t The orientation dependent plasticity in metal nanowires is investigated using molecular dynamics and dislocation wires controls the mechanisms of plastic deformation. For wires oriented along /1 1 0S, dislocations

  10. Undulator radiation simulation tools in view of proton beam diagnostics in LHC

    E-Print Network [OSTI]

    Ponce, L; CERN. Geneva. SPS and LHC Division

    2001-01-01T23:59:59.000Z

    As a superconducting undulator is planned to be used for beam diagnostics in LHC, it appeared to be necessary to adapt the simulation tools. Hence, a new procedure UNDULATOR has been implemented in the ray-tracing code Zgoubi and is assessed in this paper. After a brief recall of the numerical methods of concern, some simulations with UNDULATOR are compared, first with classical analytical models and then with field map based methods using the procedure TOSCA.

  11. Dynamic simulation of a proposed ITER tritium processing system

    SciTech Connect (OSTI)

    Kuan, W.; Abdou, M.A. [Univ. of California, Los Angeles, CA (United States); Scott W.R. [Los Alamos National Lab., NM (United States)

    1995-10-01T23:59:59.000Z

    Dynamically simulating the fuel cycle in a fusion reactor is crucial to developing a better understanding of the safe and reliable operation of this complex system. In this work, we propose a tritium processing system for ITER`s plasma exhaust. The dynamic simulation of this proposed system is then performed with the TRUFFLES (TRitiUm Fusion Fuel cycLE dynamic Simulation) model. The fuel management, storage, and fueling operations are developed and coupled with previous cryopump and fuel cleanup unit subsystems to fully realize the complete torus exhaust flow cycle. Results show that tritium inventories will vary widely depending upon reactor operation, individual subsystem and unit operation designs. A diverse collection of batch-controlled subsystems with changes in their processing parameters are simulated in this work. In particular, the effects from the fuel management subsystem`s fuel reserve and tank switching times are quantified using sensitivity studies. 6 refs., 10 figs., 2 tabs.

  12. Research Paper j Using Petri Net Tools to Study Properties and Dynamics of

    E-Print Network [OSTI]

    Rubin, Daniel L.

    Research Paper j Using Petri Net Tools to Study Properties and Dynamics of Biological Systems MOR PELEG, PHD, DANIEL RUBIN, MD, MSC, RUSS B. ALTMAN, MD, PHD A b s t r a c t Petri Nets (PNs concurrent dynamic systems is Petri Nets (PNs).1 An advantage of PNs is that they can represent system

  13. Plasticity of metallic nanostructures : molecular dynamics simulations

    E-Print Network [OSTI]

    Healy, Con

    2014-11-27T23:59:59.000Z

    During high speed cutting processes, metals are subject to high strains and strain rates. The dynamic nature of the deformation during high speed cutting makes it difficult to detect atomic scale deformation mechanisms ...

  14. Reptational dynamics in dissipative particle dynamics simulations of polymer melts

    E-Print Network [OSTI]

    P. Nikunen; I. Vattulainen; M. Karttunen

    2005-12-12T23:59:59.000Z

    Understanding the complex viscoelastic properties of polymeric liquids remains a challenge in materials science and soft matter physics. Here, we present a simple and computationally efficient criterion for the topological constraints in polymeric liquids using the Dissipative Particle Dynamics (DPD). The same approach is also applicable in other soft potential models. For short chains the model correctly reproduces Rouse-like dynamics whereas for longer chains the dynamics becomes reptational as the chain length is increased - something that is not attainable using standard DPD or other coarse-grained soft potential methods. Importantly, no new length scales or forces need to be added.

  15. Efficient tools for the simulation of flapping wing flows Jeff D. Eldredge

    E-Print Network [OSTI]

    Eldredge, Jeff

    of novel strategies for lift and propulsion using flapping wings requires the use of computational tools for an artificial boundary treatment. Results of the dynamically shed vorticity and the forces exerted are presented as the explicit introduction of an artificial boundary condition to ensure the correct behavior at infinity

  16. NREL researchers discover ways to increase accuracy in building energy simulations tools to improve predictions of

    E-Print Network [OSTI]

    the wall cavities were not insulated during construction or where the insulating material has settled properties of building materials, insulation levels, and the temperature dependence of conduction throughNREL researchers discover ways to increase accuracy in building energy simulations tools to improve

  17. Irish Fisheries Investigations No. 17 F-PRESS: A Stochastic Simulation Tool for

    E-Print Network [OSTI]

    Codling, Edward A.

    to fit in with the ICES conceptual framework for software development. F-PRESS can be used to developIrish Fisheries Investigations No. 17 F-PRESS: A Stochastic Simulation Tool for Developing ........................................................................................................................... 32 Appendix I - Summary of F-PRESS key points

  18. Projective Dynamics: Fusing Constraint Projections for Fast Simulation Sofien Bouaziz

    E-Print Network [OSTI]

    Plotkin, Joshua B.

    energy potentials that can be solved efficiently using an alternating optimization approach. Inspired Categories: I.3.7 [Computer Graphics]: Three-Dimensional Graphics--Animation; I.6.8 [Simulation and Modeling of deformable material has become an in- dispensable tool in many areas of computer graphics. Virtual worlds

  19. CVSys: A Coordination Framework for Dynamic and Fully Distributed Cardiovascular Modeling and Simulation

    E-Print Network [OSTI]

    California at Irvine, University of

    CVSys: A Coordination Framework for Dynamic and Fully Distributed Cardiovascular Modeling and dynamic simulation control. This coordination framework uniquely incorporates attributes of open indigenous and a more integrated system representation. Dynamic simulation control serves to interject new

  20. Massively parallel molecular dynamics simulations of

    E-Print Network [OSTI]

    Berne, Bruce J.

    experimental studies pioneered by Dobson and coworkers have shown that amyloids and fibrils can be formed of their three- dimensional (3D) structure and dynamics at the atomic level. This understanding can not only from the traditional beta-amyloid peptides but also from almost any proteins, such as lysozyme

  1. Programmable quantum simulation by dynamic Hamiltonian engineering

    E-Print Network [OSTI]

    David L. Hayes; Steven T. Flammia; Michael J. Biercuk

    2014-06-18T23:59:59.000Z

    Quantum simulation is a promising near term application for mesoscale quantum information processors, with the potential to solve computationally intractable problems at the scale of just a few dozen interacting quantum systems. Recent experiments in a range of technical platforms have demonstrated the basic functionality of quantum simulation applied to quantum magnetism, quantum phase transitions, and relativistic quantum mechanics. In all cases, the underlying hardware platforms restrict the achievable inter-particle interaction, forming a serious constraint on the ability to realize a versatile, programmable quantum simulator. In this work, we address this problem by developing novel sequences of unitary operations that engineer desired effective Hamiltonians in the time-domain. The result is a hybrid programmable analog simulator permitting a broad class of interacting spin-lattice models to be generated starting only with an arbitrary long-range native inter-particle interaction and single-qubit addressing. Specifically, our approach permits the generation of all symmetrically coupled translation-invariant two-body Hamiltonians with homogeneous on-site terms, a class which includes all spin-1/2 XYZ chains, but generalized to include long-range couplings. Building on previous work proving that universal simulation is possible using both entangling gates and single-qubit unitaries, we show that determining the "program" of unitary pulses to implement an arbitrary spin Hamiltonian can be formulated as a linear program that runs in polynomial time and scales efficiently in hardware resources. Our analysis extends from circuit model quantum information to adiabatic quantum evolutions, where our approach allows for the creation of non-native ground state solutions to a computation.

  2. Modeling and simulation of consumer response to dynamic pricing.

    SciTech Connect (OSTI)

    Valenzuela, J.; Thimmapuram, P.; Kim, J (Decision and Information Sciences); (Auburn Univ.)

    2012-08-01T23:59:59.000Z

    Assessing the impacts of dynamic-pricing under the smart grid concept is becoming extremely important for deciding its full deployment. In this paper, we develop a model that represents the response of consumers to dynamic pricing. In the model, consumers use forecasted day-ahead prices to shift daily energy consumption from hours when the price is expected to be high to hours when the price is expected to be low while maintaining the total energy consumption as unchanged. We integrate the consumer response model into the Electricity Market Complex Adaptive System (EMCAS). EMCAS is an agent-based model that simulates restructured electricity markets. We explore the impacts of dynamic-pricing on price spikes, peak demand, consumer energy bills, power supplier profits, and congestion costs. A simulation of an 11-node test network that includes eight generation companies and five aggregated consumers is performed for a period of 1 month. In addition, we simulate the Korean power system.

  3. Generating generalized distributions from dynamical simulation

    E-Print Network [OSTI]

    Barth, Eric J.; Laird, Brian Bostian; Leimkuhler, Benedict J.

    2003-03-18T23:59:59.000Z

    virtual momentum related to the actual momentum of the system by p5sp.3 The equations of motion generated by the Nose Hamiltonian @Eq. ~1!# are dq dt 5M 21p/s2, ~2! dp dt 52V~q!, ~3! ds dt 5 p Q , ~4! dp dt 5 pTM21p s3 2gkBT/s . ~5! The Nose method... regulates the temperature of the sys- tem through a dynamical time transformation given by dt/dt5s , where t is the Nose ~virtual! time and t is real time. The remarkable property of Nose dynamics is that mi- crocanonical sampling of the extended phase...

  4. Lessons Learned From Dynamic Simulations of Advanced Fuel Cycles

    SciTech Connect (OSTI)

    Steven J. Piet; Brent W. Dixon; Jacob J. Jacobson; Gretchen E. Matthern; David E. Shropshire

    2009-04-01T23:59:59.000Z

    Years of performing dynamic simulations of advanced nuclear fuel cycle options provide insights into how they could work and how one might transition from the current once-through fuel cycle. This paper summarizes those insights from the context of the 2005 objectives and goals of the Advanced Fuel Cycle Initiative (AFCI). Our intent is not to compare options, assess options versus those objectives and goals, nor recommend changes to those objectives and goals. Rather, we organize what we have learned from dynamic simulations in the context of the AFCI objectives for waste management, proliferation resistance, uranium utilization, and economics. Thus, we do not merely describe lessons learned from dynamic simulations but attempt to answer the so what question by using this context. The analyses have been performed using the Verifiable Fuel Cycle Simulation of Nuclear Fuel Cycle Dynamics (VISION). We observe that the 2005 objectives and goals do not address many of the inherently dynamic discriminators among advanced fuel cycle options and transitions thereof.

  5. NREL: Dynamic Maps, GIS Data, and Analysis Tools Home Page

    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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated CodesTransparency Visit | NationalWebmaster To contact the The Dynamic

  6. Mesoscale simulations of polymer dynamics in microchannel flows

    E-Print Network [OSTI]

    L. Cannavacciuolo; R. G. Winkler; G. Gompper

    2007-09-24T23:59:59.000Z

    The non-equilibrium structural and dynamical properties of flexible polymers confined in a square microchannel and exposed to a Poiseuille flow are investigated by mesoscale simulations. The chain length and the flow strength are systematically varied. Two transport regimes are identified, corresponding to weak and strong confinement. For strong confinement, the transport properties are independent of polymer length. The analysis of the long-time tumbling dynamics of short polymers yields non-periodic motion with a sublinear dependence on the flow strength. We find distinct differences for conformational as well as dynamical properties from results obtained for simple shear flow.

  7. High speed simulation of microprocessor systems using LTU dynamic binary translation

    E-Print Network [OSTI]

    Jones, Daniel

    2010-01-01T23:59:59.000Z

    This thesis presents new simulation techniques designed to speed up the simulation of microprocessor systems. The advanced simulation techniques may be applied to the simulator class which employs dynamic binary translation ...

  8. Analytical Rescaling of Polymer Dynamics from Mesoscale Simulations

    E-Print Network [OSTI]

    I. Y. Lyubimov; J. McCarty; A. Clark; M. G. Guenza

    2011-03-10T23:59:59.000Z

    We present a theoretical approach to scale the artificially fast dynamics of simulated coarse-grained polymer liquids down to its realistic value. As coarse-graining affects entropy and dissipation, two factors enter the rescaling: inclusion of intramolecular vibrational degrees of freedom, and rescaling of the friction coefficient. Because our approach is analytical, it is general and transferable. Translational and rotational diffusion of unentangled and entangled polyethylene melts, predicted from mesoscale simulations of coarse-grained polymer melts using our rescaling procedure, are in quantitative agreement with united atom simulations and with experiments.

  9. Coupled displacive and orderdisorder dynamics in LiNbO3 by molecular-dynamics simulation

    E-Print Network [OSTI]

    Gopalan, Venkatraman

    .1063/1.1669063 Ferroelectric lithium niobate (LiNbO3) has emerged as an important material in surface acoustic wave devices1 the structure and properties of materials. Indeed, atomic-level simulations have been used previously-dynamics MD simulations described here we treat the Coulomb interactions using a direct summation method

  10. DYNAMIC SIMULATION OF INEXTENSIBLE CLOTH Jan Bender, Daniel Bayer and Raphael Diziol

    E-Print Network [OSTI]

    Prautzsch, Hartmut

    DYNAMIC SIMULATION OF INEXTENSIBLE CLOTH Jan Bender, Daniel Bayer and Raphael Diziol Institut für-based modelling, impulse-based simulation, inelastic textiles 1. INTRODUCTION The dynamic simulation of cloth an efficient simulation. For example, Georgii and Westermann (2005) describe a method for a fast dynamic

  11. Application of Dynamic Monte Carlo Technique in Proton Beam Radiotherapy using Geant4 Simulation Toolkit

    E-Print Network [OSTI]

    Guan, Fada 1982-

    2012-04-27T23:59:59.000Z

    Monte Carlo method has been successfully applied in simulating the particles transport problems. Most of the Monte Carlo simulation tools are static and they can only be used to perform the static simulations for the problems with fixed physics...

  12. Application of Dynamic Monte Carlo Technique in Proton Beam Radiotherapy using Geant4 Simulation Toolkit

    E-Print Network [OSTI]

    Guan, Fada 1982-

    2012-04-27T23:59:59.000Z

    Monte Carlo method has been successfully applied in simulating the particles transport problems. Most of the Monte Carlo simulation tools are static and they can only be used to perform the static simulations for the problems with fixed physics...

  13. Modifying the Soil and Water Assessment Tool to Simulate Cropland Carbon Flux: Model Development and Initial Evaluation

    SciTech Connect (OSTI)

    Zhang, Xuesong; Izaurralde, Roberto C.; Arnold, Jeffrey; Williams, Jimmy R.; Srinivasan, Raghavan

    2013-10-01T23:59:59.000Z

    Climate change is one of the most compelling modern issues and has important implications for almost every aspect of natural and human systems. The Soil and Water Assessment Tool (SWAT) model has been applied worldwide to support sustainable land and water management in a changing climate. However, the inadequacies of the existing carbon algorithm in SWAT limit its application in assessing impacts of human activities on CO2 emission, one important source of greenhouse gases (GHGs) that traps heat in the earth system and results in global warming. In this research, we incorporate a revised version of the CENTURY carbon model into SWAT to describe dynamics of soil organic matter (SOM)- residue and simulate land-atmosphere carbon exchange.

  14. adhesive dynamics simulation: Topics by E-print Network

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

    adhesive dynamics simulation First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 A composite time...

  15. Hydrogen Raman shifts in carbon nanotubes from molecular dynamics simulation

    E-Print Network [OSTI]

    Brenner, Donald W.

    Hydrogen Raman shifts in carbon nanotubes from molecular dynamics simulation S.J.V. Frankland *, D hydrogen in individual single-shell carbon nanotubes and nanotube ropes using a semiclassical model. The calculations predict that isolated hydrogen molecules inside of nanotubes have a Raman frequency that increases

  16. Simulation of electron cooling dynamic ( December 16, 2003)

    E-Print Network [OSTI]

    approach in BetaCool code also leads to fast cooling of beam core ­ benchmarking in progress different and momentum are being benchmarked cooling #12;Progress · We have better understanding of friction forceSimulation of electron cooling dynamic ( December 16, 2003) A. Fedotov, I. Ben-zvi, Yu. Eidelman, V

  17. Dynamic Simulation of DFIG Wind Turbines on FPGA Boards

    E-Print Network [OSTI]

    Zambreno, Joseph A.

    Dynamic Simulation of DFIG Wind Turbines on FPGA Boards Hao Chen, Student Member, IEEE, Song Sun is a friction coefficient. The wind turbine model is based on the relation between the upstream wind speed V w + 1 where p is the air density; Rw is the wind turbine radius; cp (A, (3) is the performance

  18. Thermodiffusion in model nanofluids by molecular dynamics simulations

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    1 Thermodiffusion in model nanofluids by molecular dynamics simulations G. Galliero1,2,* , S. Volz3-Jones fluids and for model nanofluids (spherical non-metallic nanoparticles + Lennard-Jones fluid) where concentration. Then, in nanofluids in the liquid state, by changing the nature of the nanoparticle (size, mass

  19. Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine

    E-Print Network [OSTI]

    Rapaport, Dennis C.

    Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine D 2009; published 30 April 2009 A nanoscale-sized Stirling engine with an atomistic working fluid has s : 02.70.Ns, 05.70.Ln, 47.61. k The Stirling engine, an external combustion engine in- vented almost two

  20. Simulation of the Dynamic Inefficiency of the CMS Pixel Detector

    E-Print Network [OSTI]

    Mrton Bartk

    2015-01-22T23:59:59.000Z

    The Pixel Detector is the innermost part of the CMS Tracker. It therefore has to prevail in the harshest environment in terms of particle fluence and radiation. There are several mechanisms that may decrease the efficiency of the detector. These are mainly caused by data acquisition (DAQ) problems and/or Single Event Upsets (SEU). Any remaining efficiency loss is referred to as the dynamic inefficiency. It is caused by various mechanisms inside the Readout Chip (ROC) and depends strongly on the data occupancy. In the 2012 data, at high values of instantaneous luminosity the inefficiency reached 2\\% (in the region closest to the interaction point) which is not negligible. In the 2015 run higher instantaneous luminosity is expected, which will result in lower efficiencies; therefore this effect needs to be understood and simulated. A data-driven method has been developed to simulate dynamic inefficiency, which has been shown to successfully simulate the effects.

  1. Mesoscale simulation of polymer reaction equilibrium: Combining dissipative particle dynamics with reaction

    E-Print Network [OSTI]

    Lisal, Martin

    Mesoscale simulation of polymer reaction equilibrium: Combining dissipative particle dynamics. R. Smith, J. Chem. Phys. 125, 16490 2006 , a mesoscale simulation technique for studying polymer

  2. SPEE: A Secure Program Execution Environment Tool Using Static and Dynamic Code Verification

    E-Print Network [OSTI]

    Simha, Rahul

    SPEE: A Secure Program Execution Environment Tool Using Static and Dynamic Code Verification Olga those using the Internet and exploiting the vul- nerabilities in the software and applications, software ­ for software integrity protection and authentication and presents performance results. Our system architecture

  3. Power Flow Modelling of Dynamic Systems - Introduction to Modern Teaching Tools

    E-Print Network [OSTI]

    Geitner, Gert-Helge

    2015-01-01T23:59:59.000Z

    As tools for dynamic system modelling both conventional methods such as transfer function or state space representation and modern power flow based methods are available. The latter methods do not depend on energy domain, are able to preserve physical system structures, visualize power conversion or coupling or split, identify power losses or storage, run on conventional software and emphasize the relevance of energy as basic principle of known physical domains. Nevertheless common control structures as well as analysis and design tools may still be applied. Furthermore the generalization of power flow methods as pseudo-power flow provides with a universal tool for any dynamic modelling. The phenomenon of power flow constitutes an up to date education methodology. Thus the paper summarizes fundamentals of selected power flow oriented modelling methods, presents a Bond Graph block library for teaching power oriented modelling as compact menu-driven freeware, introduces selected examples and discusses special f...

  4. Generic solar photovoltaic system dynamic simulation model specification.

    SciTech Connect (OSTI)

    Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas

    2013-10-01T23:59:59.000Z

    This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.

  5. Mesoscale simulation of polymer reaction equilibrium: Combining dissipative particle dynamics with reaction ensemble Monte Carlo.

    E-Print Network [OSTI]

    Lisal, Martin

    Mesoscale simulation of polymer reaction equilibrium: Combining dissipative particle dynamics a mesoscale simulation technique, called the reaction ensemble dissipative particle dynamics RxDPD method. Coarse-grained, particle- based mesoscale models that retain only the most essential features

  6. Lightweight Object Oriented Structure Analysis: Tools for Building Tools to Analyze Molecular Dynamics Simulations

    E-Print Network [OSTI]

    , such as carma/ grcarma. There are nearly 14,000 lines of C code in carma and grcarma, the graphical front. The "actions" module, which contains many analy- sis routines, consists of nearly 20,000 lines of C code units. Actions use a common programming interface via subclassing and the "command" design pattern

  7. Dislocation dynamics simulations of plasticity at small scales

    SciTech Connect (OSTI)

    Zhou, Caizhi

    2010-12-15T23:59:59.000Z

    As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests. The primary objective of this research is to use 3-D DD simulations to study the plastic deformation of nano- and micro-scale materials and understand the correlation between dislocation motion, interactions and the mechanical response. Specifically, to identify what critical events (i.e., dislocation multiplication, cross-slip, storage, nucleation, junction and dipole formation, pinning etc.) determine the deformation response and how these change from bulk behavior as the system decreases in size and correlate and improve our current knowledge of bulk plasticity with the knowledge gained from the direct observations of small-scale plasticity. Our simulation results on single crystal micropillars and polycrystalline thin films can march the experiment results well and capture the essential features in small-scale plasticity. Furthermore, several simple and accurate models have been developed following our simulation results and can reasonably predict the plastic behavior of small scale materials.

  8. Development of directional capabilities to an ultradeep water dynamic kill simulator and simulations runs

    E-Print Network [OSTI]

    Meier, Hector Ulysses

    2005-11-01T23:59:59.000Z

    . Unfortunately with greater challenges there are greater risks of losing control and blowing out a well. A dynamic kill simulator was developed in late 2004 to model initial conditions of a blowout in ultradeep water and to calculate the minimum kill rate...

  9. Transient Solid Dynamics Simulations on the Sandia/Intel Teraflop Computer

    E-Print Network [OSTI]

    Hendrickson, Bruce

    and structure of PRONTO. In Section 3 we explain why transient dynamics simulations have been difficultTransient Solid Dynamics Simulations on the Sandia/Intel Teraflop Computer Stephen Attaway \\Lambda Plimpton \\Lambda and Courtenay Vaughan \\Lambda Abstract Transient solid dynamics simulations are among

  10. Building Design Advisor: Automated integration of multiple simulation tools K. Papamichael, J. LaPorta, H. Chauvet

    E-Print Network [OSTI]

    LBNL-40591 Preprint Building Design Advisor: Automated integration of multiple simulation tools K. Papamichael, J. LaPorta, H. Chauvet Building Technologies Program Environmental Energy Technologies Division Ernest Orlando Lawrence Berkeley National Laboratory Berkeley, California 94720 Abstract The Building

  11. A Distributed Electrochemistry Modeling Tool for Simulating SOFC Performance and Degradation

    SciTech Connect (OSTI)

    Recknagle, Kurtis P.; Ryan, Emily M.; Khaleel, Mohammad A.

    2011-10-13T23:59:59.000Z

    This report presents a distributed electrochemistry (DEC) model capable of investigating the electrochemistry and local conditions with the SOFC MEA based on the local microstructure and multi-physics. The DEC model can calculate the global current-voltage (I-V) performance of the cell as determined by the spatially varying local conditions through the thickness of the electrodes and electrolyte. The simulation tool is able to investigate the electrochemical performance based on characteristics of the electrode microstructure, such as particle size, pore size, electrolyte and electrode phase volume fractions, and triple-phase-boundary length. It can also investigate performance as affected by fuel and oxidant gas flow distributions and other environmental/experimental conditions such as temperature and fuel gas composition. The long-term objective for the DEC modeling tool is to investigate factors that cause electrode degradation and the decay of SOFC performance which decrease longevity.

  12. Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine

    E-Print Network [OSTI]

    Rapaport, D C

    2009-01-01T23:59:59.000Z

    A nanoscale-sized Stirling engine with an atomistic working fluid has been modeled using molecular dynamics simulation. The design includes heat exchangers based on thermostats, pistons attached to a flywheel under load, and a regenerator. Key aspects of the behavior, including the time-dependent flows, are described. The model is shown to be capable of stable operation while producing net work at a moderate level of efficiency.

  13. Long-term system dynamics simulation methods. Final report

    SciTech Connect (OSTI)

    Manke, J.W.; Pauly, W.R.; Hemmaplardh, K.

    1985-02-01T23:59:59.000Z

    The focus of long-term dynamic simulations is to analyze the effects of wide excursions of voltage, frequency and power flows for extended periods of time on the bulk power system. The emphasis on modeling the sequence of system events over an extended period of time that follows a major disturbance distinguishes long-term dynamics from transient and midterm stability analysis where the effects of inter-machine oscillations on synchronous machines is the primary focus. The assumption of a uniform system frequency during quiscent system conditions makes it possible to use a numerical stepsize of one or more seconds for long-term studies, as opposed to a fraction of a cycle for transient/midterm stability, and to simulate the voltage and frequency effects of such system events as automatic load shedding and unit tripping for long periods of time. Both the time frame and the type of system events of interest in long-term dynamic studies establish the modeling and simulation requirements for a long-term program and the need for system data to validate the models and program. The sequence of system events that occur during the long-term time frame may introduce step changes in the system, i.e., load shedding, which cause transients that must be modeled on the transient stability time scale. This is the basis for the requirements that a long-term program have an adequate interface with a transient stability program.

  14. Reweighted ensemble dynamics simulations: theory, improvement, and application

    E-Print Network [OSTI]

    Linchen Gong; Xin Zhou; Zhong-Can Ou-Yang

    2015-02-22T23:59:59.000Z

    Based on multiple parallel short molecular dynamics simulation trajectories, we designed the reweighted ensemble dynamics (RED) method to more efficiently sample complex (biopolymer) systems, and to explore their hierarchical metastable states. Here we further present an improvement to depress statistical errors of the RED and we discuss a few keys in practical application of the RED, provides schemes on selection of basis functions, determination of free parameter in the RED. We illustrate the application of the improvements in two toy models and in the solvated alanine dipeptide. The results show the RED enable to capture the topology of multiple-state transition networks, to detect the diffusion-like dynamical behavior in entropy-dominated system, and to identify solvent effects in the solvated peptides. The illustrations serve as general applications of the RED in more complex biopolymer systems.

  15. Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

    SciTech Connect (OSTI)

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M; Benedict, L; Hau-Riege, S; Langdon, A; London, R

    2008-02-14T23:59:59.000Z

    The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.

  16. Large-Scale Molecular Dynamics Simulations for Highly Parallel Infrastructures

    E-Print Network [OSTI]

    Pazrikov, Jana

    2014-01-01T23:59:59.000Z

    Computational chemistry allows researchers to experiment in sillico: by running a computer simulations of a biological or chemical processes of interest. Molecular dynamics with molecular mechanics model of interactions simulates N-body problem of atoms$-$it computes movements of atoms according to Newtonian physics and empirical descriptions of atomic electrostatic interactions. These simulations require high performance computing resources, as evaluations within each step are computationally demanding and billions of steps are needed to reach interesting timescales. Current methods decompose the spatial domain of the problem and calculate on parallel/distributed infrastructures. Even the methods with the highest strong scaling hit the limit at half a million cores: they are not able to cut the time to result if provided with more processors. At the dawn of exascale computing with massively parallel computational resources, we want to increase the level of parallelism by incorporating parallel-in-time comput...

  17. New Structural-Dynamics Module for Offshore Multimember Substructures within the Wind Turbine Computer-Aided Engineering Tool FAST: Preprint

    SciTech Connect (OSTI)

    Song, H.; Damiani, R.; Robertson, A.; Jonkman, J.

    2013-08-01T23:59:59.000Z

    FAST, developed by the National Renewable Energy Laboratory (NREL), is a computer-aided engineering (CAE) tool for aero-hydro-servo-elastic analysis of land-based and offshore wind turbines. This paper discusses recent upgrades made to FAST to enable loads simulations of offshore wind turbines with fixed-bottom, multimember support structures (e.g., jackets and tripods, which are commonly used in transitional-depth waters). The main theory and strategies for the implementation of the multimember substructure dynamics module (SubDyn) within the new FAST modularization framework are introduced. SubDyn relies on two main engineering schematizations: 1) a linear frame finite-element beam (LFEB) model and 2) a dynamics system reduction via Craig-Bampton's method. A jacket support structure and an offshore system consisting of a turbine atop a jacket substructure were simulated to test the SubDyn module and to preliminarily assess results against results from a commercial finite-element code.

  18. Molecular Dynamics Simulations from SNL's Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Plimpton, Steve; Thompson, Aidan; Crozier, Paul

    LAMMPS (http://lammps.sandia.gov/index.html) stands for Large-scale Atomic/Molecular Massively Parallel Simulator and is a code that can be used to model atoms or, as the LAMMPS website says, as a parallel particle simulator at the atomic, meso, or continuum scale. This Sandia-based website provides a long list of animations from large simulations. These were created using different visualization packages to read LAMMPS output, and each one provides the name of the PI and a brief description of the work done or visualization package used. See also the static images produced from simulations at http://lammps.sandia.gov/pictures.html The foundation paper for LAMMPS is: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), but the website also lists other papers describing contributions to LAMMPS over the years.

  19. Structure and dynamics of nonaqueous mixtures of dipolar liquids. II. Molecular dynamics simulations

    E-Print Network [OSTI]

    2000 Molecular dynamics simulations have been used to study mixtures of acetone/methanol, acetonitrile/ methanol, and acetone/acetonitrile over their entire composition range. Using the effective pair potentials in these two papers is on the nonaqueous dipolar liquid mixtures of acetone/methanol, acetonitrile

  20. Role of dynamics in tuning fidelity of RNA-dependent RNA polymerase elucidated by molecular dynamics simulation

    E-Print Network [OSTI]

    Bjrnstad, Ottar Nordal

    Role of dynamics in tuning fidelity of RNA-dependent RNA polymerase elucidated by molecular dynamics simulation Ibrahim M. Moustafa Department of Biochemistry and Molecular Biology Eberly College fidelity is not clear but suggested to be linked to dynamics of the enzyme [1]. By using molecular dynamics

  1. The Cognitive Environment Simulation as a tool for modeling human performance and reliability

    SciTech Connect (OSTI)

    Woods, D.D. (Ohio State Univ., Columbus, OH (USA). Cognitive Systems Engineering Lab.); Pople, H.E. Jr. (Seer Systems (USA)); Roth, E.M. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Science and Technology Center)

    1990-06-01T23:59:59.000Z

    The US Nuclear Regulatory Commission is sponsoring a program to develop improved methods to model the cognitive behavior of nuclear power plant (NPP) personnel. A tool called Cognitive Environment Simulation (CES) was developed for simulating how people form intentions to act in NPP emergencies. CES provides an analytic tool for exploring plausible human responses in emergency situations. In addition a methodology called Cognitive Reliability Assessment Technique (CREATE) was developed that describes how CES can be used to provide input to human reliability analyses (HRA) in probabilistic risk assessment (PRA) studies. This report describes the results of three activities that were performed to evaluate CES/CREATE: (1) A technical review was conducted by a panel of experts in cognitive modeling, PRA and HRA; (2) CES was exercised on steam generator tube rupture incidents for which data on operator performance exist; (3) a workshop with HRA practitioners was held to analyze a worked example'' of the CREATE methodology. The results of all three evaluations indicate that CES/CREATE is a promising approach for modeling intention formation. Volume 1 provides a summary of the results. This document, Volume 2, provides details on the three evaluations, including the CES computer outputs for the tube rupture events. 18 refs., 9 figs., 5 tabs.

  2. The Cognitive Environment Simulation as a tool for modeling human performance and reliability

    SciTech Connect (OSTI)

    Woods, D.D. (Ohio State Univ., Columbus, OH (USA). Cognitive Systems Engineering Lab.); Pople, H.E. Jr. (Seer Systems (USA)); Roth, E.M. (Westinghouse Electric Corp., Pittsburgh, PA (USA). Science and Technology Center)

    1990-06-01T23:59:59.000Z

    The US Nuclear Regulatory Commission is sponsoring a program to develop improved methods to model the cognitive behavior of nuclear power plant (NPP) personnel. A tool called Cognitive Environment Simulation (CES) was developed for simulating how people form intentions to act in NPP emergencies. CES provides an analytic tool for exploring plausible human response in emergency situations. In addition a methodology called Cognitive Reliability Assessment Technique (CREATE) was developed that describes how CES can be used to provide input to human reliability analyses (HRA) in probabilistic risk assessment (PRA) studies. This report describes the results of three activities that were performed to evaluate CES/CREATE: (1) A technical review was conducted by a panel of experts in cognitive modeling, PRA and HRA; (2) CES was exercised on steam generator tube rupture incidents for which data on operator performance exist; (3) a workshop with HRA practitioners was held to analyze a worked example'' of the CREATE methodology. The results of all three evaluations indicate that CES/CREATE is a promising approach for modeling intention formation. This document, Volume 1 provides a summary of the results. Volume 2 provides details on three evaluations, including the CES computer outputs for the tube rupture events. 14 refs., 3 figs.

  3. An Introduction to MolecularAn Introduction to Molecular Dynamics SimulationsDynamics Simulations

    E-Print Network [OSTI]

    Mura, Cameron

    details · Strengths & weaknesses · Force fields · Available software; pros & cons; how to do a simulation) from Talkington, Siuzdak, Williamson, Nature v438 (2005) CameronMura;May2007 #12;Background) systems: noble gas elements, etc. theoretical and organic chemistry fields; 196070s theoretical

  4. Assessment of Tools and Data for System-Level Dynamic Analyses

    SciTech Connect (OSTI)

    Steven J. Piet; Nick R. Soelberg

    2011-06-01T23:59:59.000Z

    The only fuel cycle for which dynamic analyses and assessments are not needed is the null fuel cycle - no nuclear power. For every other concept, dynamic analyses are needed and can influence relative desirability of options. Dynamic analyses show how a fuel cycle might work during transitions from today's partial fuel cycle to something more complete, impact of technology deployments, location of choke points, the key time lags, when benefits can manifest, and how well parts of fuel cycles work together. This report summarizes the readiness of existing Fuel Cycle Technology (FCT) tools and data for conducting dynamic analyses on the range of options. VISION is the primary dynamic analysis tool. Not only does it model mass flows, as do other dynamic system analysis models, but it allows users to explore various potential constraints. The only fuel cycle for which constraints are not important are those in concept advocates PowerPoint presentations; in contrast, comparative analyses of fuel cycles must address what constraints exist and how they could impact performance. The most immediate tool need is extending VISION to the thorium/U233 fuel cycle. Depending on further clarification of waste management strategies in general and for specific fuel cycle candidates, waste management sub-models in VISION may need enhancement, e.g., more on 'co-flows' of non-fuel materials, constraints in waste streams, or automatic classification of waste streams on the basis of user-specified rules. VISION originally had an economic sub-model. The economic calculations were deemed unnecessary in later versions so it was retired. Eventually, the program will need to restore and improve the economics sub-model of VISION to at least the cash flow stage and possibly to incorporating cost constraints and feedbacks. There are multiple sources of data that dynamic analyses can draw on. In this report, 'data' means experimental data, data from more detailed theoretical or empirical calculations on technology performance, and assumptions such as the earliest date a technology can be deployed. The only fuel cycles for which we currently have adequate data are those we are sure we will never build, e.g., a PUREX plant in the U.S. For actual candidates, even for once through LWRs, there remain missing data such as how the fuel cycle would be completed with a geologic repository. The most immediate data needs are probably basic reactor physics data for new concepts and data associated with waste management for anything other than current technology. The readiness of tools and data is fluid and depends on what purposes are envisioned to drive upcoming analyses and further definition of the waste-related characteristics of fuel cycle candidates. Tools and data sets evolve as needs evolve. Thus, much of the document explains that if the FCT program wants a certain type of analysis, then the tools and data needs are as indicated. For example, functions can be treated as either commodities or facilities. Reactors, separation, fuel fabrication, repository are treated as facility types. Other functions such as uranium mining, conversion, enrichment, and waste packaging and non-repository disposal are treated as commodities and therefore not modeled as extensively. In summary, the tools are functional and can answer many fuel cycle questions but some analyses will require that the tools be modified to support those analyses.

  5. Thermostat for non-equilibrium multiparticle collision dynamics simulations

    E-Print Network [OSTI]

    Chien-Cheng Huang; Anoop Varghese; Gerhard Gompper; Roland G. Winkler

    2015-01-23T23:59:59.000Z

    Multiparticle collision dynamics (MPC), a particle-based mesoscale simulation technique for com- plex fluid, is widely employed in non-equilibrium simulations of soft matter systems. To maintain a defined thermodynamic state, thermalization of the fluid is often required for certain MPC variants. We investigate the influence of three thermostats on the non-equilibrium properties of a MPC fluid under shear or in Poiseuille flow. In all cases, the local velocities are scaled by a factor, which is either determined via a local simple scaling approach (LSS), a Monte Carlo-like procedure (MCS), or by the Maxwell-Boltzmann distribution of kinetic energy (MBS). We find that the various scal- ing schemes leave the flow profile unchanged and maintain the local temperature well. The fluid viscosities extracted from the various simulations are in close agreement. Moreover, the numerically determined viscosities are in remarkably good agreement with the respective theoretically predicted values. At equilibrium, the calculation of the dynamic structure factor reveals that the MBS method closely resembles an isothermal ensemble, whereas the MCS procedure exhibits signatures of an adi- abatic system at larger collision-time steps. Since the velocity distribution of the LSS approach is non-Gaussian, we recommend to apply the MBS thermostat, which has been shown to produce the correct velocity distribution even under non-equilibrium conditions.

  6. Learning environment simulator: a tool for local decision makers and first responders

    SciTech Connect (OSTI)

    Leclaire, Rene J [Los Alamos National Laboratory; Hirsch, Gary B [CLE, INCORPORATED

    2009-01-01T23:59:59.000Z

    The National Infrastructure Simulation and Analysis Center (NISAC) has developed a prototype learning environment simulator (LES) based on the Critical Infrastructure Protection Decision Support System (CIPDSS) infrastructure and scenario models. The LES is designed to engage decision makers at the grass-roots level (local/city/state) to deepen their understanding of an evolving crisis, enhance their intuition and allow them to test their own strategies for events before they occur. An initial version is being developed, centered on a pandemic influenza outbreak and has been successfully tested with a group of hospital administrators and first responders. LES is not a predictive tool but rather a simulated environment allowing the user to experience the complexities of a crisis before it happens. Users can contrast various approaches to the crisis, competing with alternative strategies of their own or other participants. LES is designed to assist decision makers in making informed choices by functionally representing relevant scenarios before they occur, including impacts to critical infrastructures with their interdependencies, and estimating human health & safety and economic impacts. In this paper a brief overview of the underlying models are given followed by a description of the LES, its interface and usage and an overview of the experience testing LES with a group of hospital administrators and first responders. The paper concludes with a brief discussion of the work remaining to make LES operational.

  7. Dynamic Simulation and Optimization of Nuclear Hydrogen Production Systems

    SciTech Connect (OSTI)

    Paul I. Barton; Mujid S. Kaximi; Georgios Bollas; Patricio Ramirez Munoz

    2009-07-31T23:59:59.000Z

    This project is part of a research effort to design a hydrogen plant and its interface with a nuclear reactor. This project developed a dynamic modeling, simulation and optimization environment for nuclear hydrogen production systems. A hybrid discrete/continuous model captures both the continuous dynamics of the nuclear plant, the hydrogen plant, and their interface, along with discrete events such as major upsets. This hybrid model makes us of accurate thermodynamic sub-models for the description of phase and reaction equilibria in the thermochemical reactor. Use of the detailed thermodynamic models will allow researchers to examine the process in detail and have confidence in the accurary of the property package they use.

  8. Molecular Dynamics Simulation of Collisions between Hydrogen and Graphite

    E-Print Network [OSTI]

    A. Ito; H. Nakamura

    2006-04-26T23:59:59.000Z

    Hydrogen adsorption by graphite is examined by classical molecular dynamics simulation using a modified Brenner REBO potential. Such interactions are typical in chemical sputtering experiments, and knowledge of the fundamental behavior of hydrogen and graphene in collisional conditions is essential for modeling the sputtering mechanism. The hydrogen adsorption rate is found to be dependent on the incident hydrogen energy and not on graphene temperature. Rather than destroying the graphene, hydrogen incidence at energies of less than 100 eV can be classified into three regimes of adsorption, reflection and penetration through one or more graphene layers. Incidence at the lowest energies is shown to distort the graphene structure.

  9. Investigations of Solar Prominence Dynamics Using Laboratory Simulations

    SciTech Connect (OSTI)

    Paul M Bellan

    2008-05-28T23:59:59.000Z

    Laboratory experiments simulating many of the dynamical features of solar coronal loops have been carried out. These experiments manifest collimation, kinking, jet flows, and S-shapes. Diagnostics include high-speed photography and x-ray detectors. Two loops having opposite or the same magnetic helicity polarities have been merged and it is found that counter-helicity merging provides much greater x-ray emission. A non-MHD particle orbit instability has been discovered whereby ions going in the opposite direction of the current flow direction can be ejected from a magnetic flux tube.

  10. Molecular Dynamics Simulations of Shock-Induced Thermite Reaction Vikas Tomar1,a

    E-Print Network [OSTI]

    Tomar, Vikas

    Molecular Dynamics Simulations of Shock-Induced Thermite Reaction Vikas Tomar1,a and Min Zhou1,b 1 Dynamics, Thermite Mixture Abstract. A computational framework for molecular dynamics (MD) simulations of shock-induced reactions in thermite mixtures is developed. The system under study is an Fe2O3+Al

  11. Semiclassical molecular dynamics simulations of excited state double-proton transfer in 7-azaindole dimers

    E-Print Network [OSTI]

    Miller, William H.

    Semiclassical molecular dynamics simulations of excited state double-proton transfer in 7-azaindole chemical re- action. In this paper we report the first application of molecular dynamics simulation methods to model the excited state double-proton transfer dynamics involved in the tau- tomerization reaction

  12. Numerical Stability and Convergence Analysis of Geometric Constraint Enforcement in Dynamic Simulation Systems

    E-Print Network [OSTI]

    Choi, Min-Hyung

    Simulation Systems Hongjun Jeon1 Min-Hyung Choi2 Min Hong3 1 Dept. of Electrical and Computer Engineering and trajectories of dynamically simulated entities. Therefore, effective and efficient enforcement and proper describes the formulation and integration of geometric constraints in a dynamic simulation and provides

  13. Spatially resolved dynamic structure factor of finite systems from molecular dynamics simulations

    SciTech Connect (OSTI)

    Raitza, Thomas; Roepke, Gerd; Reinholz, Heidi; Morozov, Igor [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Institut fuer Theoretische Physik, Johannes-Kepler-Universitaet Linz, A-4040 Linz, Austria and Institute of Physics, University of Western Australia, Perth, WA 6009 (Australia); Joint Institute for High Temperatures of RAS, 13 Izhorskaya Street, Building 2, Moscow RU-125412 (Russian Federation)

    2011-09-15T23:59:59.000Z

    The dynamical response of metallic clusters up to 10{sup 3} atoms is investigated using the restricted molecular dynamics simulations scheme. Exemplarily, a sodium like material is considered. Correlation functions are evaluated to investigate the spatial structure of collective electron excitations and the optical response of laser-excited clusters. In particular, the spectrum of bilocal correlation functions shows resonances representing different modes of collective excitations inside the nano plasma. The spatial structure, the resonance energy, and the width of the eigenmodes have been investigated for various values of electron density, temperature, cluster size, and ionization degree. Comparison with bulk properties is performed and the dispersion relation of collective excitations is discussed.

  14. Viscoroute 2.0: a tool for the simulation of moving load effects on asphalt pavement

    E-Print Network [OSTI]

    Chabot, Armelle; Deloffre, Lydie; Duhamel, Denis

    2010-01-01T23:59:59.000Z

    As shown by strains measured on full scale experimental aircraft structures, traffic of slow-moving multiple loads leads to asymmetric transverse strains that can be higher than longitudinal strains at the bottom of asphalt pavement layers. To analyze this effect, a model and a software called ViscoRoute have been developed. In these tools, the structure is represented by a multilayered half-space, the thermo-viscoelastic behaviour of asphalt layers is accounted by the Huet-Sayegh rheological law and loads are assumed to move at constant speed. First, the paper presents a comparison of results obtained with ViscoRoute to results stemming from the specialized literature. For thick asphalt pavement and several configurations of moving loads, other ViscoRoute simulations confirm that it is necessary to incorporate viscoelastic effects in the modelling to well predict the pavement behaviour and to anticipate possible damages in the structure.

  15. Current status of MCNP6 as a simulation tool useful for space and accelerator applications

    SciTech Connect (OSTI)

    Mashnik, Stepan G [Los Alamos National Laboratory; Bull, Jeffrey S [Los Alamos National Laboratory; Hughes, H. Grady [Los Alamos National Laboratory; Prael, Richard E [Los Alamos National Laboratory; Sierk, Arnold J [Los Alamos National Laboratory

    2012-07-20T23:59:59.000Z

    For the past several years, a major effort has been undertaken at Los Alamos National Laboratory (LANL) to develop the transport code MCNP6, the latest LANL Monte-Carlo transport code representing a merger and improvement of MCNP5 and MCNPX. We emphasize a description of the latest developments of MCNP6 at higher energies to improve its reliability in calculating rare-isotope production, high-energy cumulative particle production, and a gamut of reactions important for space-radiation shielding, cosmic-ray propagation, and accelerator applications. We present several examples of validation and verification of MCNP6 compared to a wide variety of intermediate- and high-energy experimental data on reactions induced by photons, mesons, nucleons, and nuclei at energies from tens of MeV to about 1 TeV/nucleon, and compare to results from other modern simulation tools.

  16. HyPro: A Financial Tool for Simulating Hydrogen Infrastructure Development, Final Report

    SciTech Connect (OSTI)

    Brian D. James, Peter O. Schmidt, Julie Perez

    2008-12-01T23:59:59.000Z

    This report summarizes a multi-year Directed Technologies Inc. (DTI) project to study the build-out of hydrogen production facilities during the transition from gasoline internal combustion engine vehicle to hydrogen fuel cell vehicles. The primary objectives of the project are to develop an enhanced understanding of hydrogen production issues during the transition period (out to 2050) and to develop recommendations for the DOE on areas of further study. These objectives are achieved by conducting economic and scenario analysis to predict how industry would provide the hydrogen production, delivery and dispensing capabilities necessary to satisfy increased hydrogen demand. The primary tool used for the analysis is a custom created MatLab simulation tool entitled HyPro (short for Hydrogen Production). This report describes the calculation methodology used in HyPro, the baseline assumptions, the results of the baseline analysis and several corollary studies. The appendices of this report included a complete listing of model assumptions (capital costs, efficiencies, feedstock prices, delivery distances, etc.) and a step-by-step manual on the specific operation of the HyPro program. This study was made possible with funding from the U.S. Department of Energy (DOE).

  17. Equilibration of experimentally determined protein structures for molecular dynamics simulation Emily B. Walton and Krystyn J. VanVliet*

    E-Print Network [OSTI]

    Van Vliet, Krystyn J.

    Equilibration of experimentally determined protein structures for molecular dynamics simulation well studied, ranging from refinements of static x-ray crystallog- raphy structures to dynamic Preceding molecular dynamics simulations of biomolecular interactions, the molecule of interest is often

  18. MOLECULAR DYNAMICS SIMULATIONS OF DISPLACEMENT CASCADES IN MOLYBDENUM

    SciTech Connect (OSTI)

    Smith, Richard Whiting

    2003-09-08T23:59:59.000Z

    Molecular dynamics calculations have been employed to simulate displacement cascades in neutron irradiated Mo. A total of 90 simulations were conducted for PKA energies between 1 and 40 keV and temperatures from 298 to 923K. The results suggest very little effect of temperature on final defect count and configuration, but do display a temperature effect on peak defect generation prior to cascade collapse. Cascade efficiency, relative to the NRT model, is computed to lie between 1/4 and 1/3 in agreement with simulations performed on previous systems. There is a tendency for both interstitials and vacancies to cluster together following cascade collapse producing vacancy rich regions surrounded by interstitials. Although coming to rest in close proximity, the point defects comprising the clusters generally do not lie within the nearest neighbor positions of one another, except for the formation of dumbbell di-interstitials. Cascades produced at higher PKA energies (20 or 40 keV) exhibit the formation of subcascades.

  19. Pasta Nucleosynthesis: Molecular dynamics simulations of nuclear statistical equilibrium

    E-Print Network [OSTI]

    M. E. Caplan; A. S. Schneider; C. J. Horowitz; D. K. Berry

    2014-12-29T23:59:59.000Z

    Background: Exotic non-spherical nuclear pasta shapes are expected in nuclear matter at just below saturation density because of competition between short range nuclear attraction and long range Coulomb repulsion. Purpose: We explore the impact of nuclear pasta on nucleosynthesis, during neutron star mergers, as cold dense nuclear matter is ejected and decompressed. Methods: We perform classical molecular dynamics simulations with 51200 and 409600 nucleons, that are run on GPUs. We expand our simulation region to decompress systems from an initial density of 0.080 fm^{-3} down to 0.00125 fm^{-3}. We study proton fractions of Y_P=0.05, 0.10, 0.20, 0.30, and 0.40 at T =0.5, 0.75, and 1.0 MeV. We calculate the composition of the resulting systems using a cluster algorithm. Results: We find final compositions that are in good agreement with nuclear statistical equilibrium models for temperatures of 0.75 and 1 MeV. However, for proton fractions greater than Y_P=0.2 at a temperature of T = 0.5 MeV, the MD simulations produce non-equilibrium results with large rod-like nuclei. Conclusions: Our MD model is valid at higher densities than simple nuclear statistical equilibrium models and may help determine the initial temperatures and proton fractions of matter ejected in mergers.

  20. Physics and Algorithm Enhancements for a Validated MCNP/X Monte Carlo Simulation Tool, Phase VII

    SciTech Connect (OSTI)

    McKinney, Gregg W [Los Alamos National Laboratory

    2012-07-17T23:59:59.000Z

    Currently the US lacks an end-to-end (i.e., source-to-detector) radiation transport simulation code with predictive capability for the broad range of DHS nuclear material detection applications. For example, gaps in the physics, along with inadequate analysis algorithms, make it difficult for Monte Carlo simulations to provide a comprehensive evaluation, design, and optimization of proposed interrogation systems. With the development and implementation of several key physics and algorithm enhancements, along with needed improvements in evaluated data and benchmark measurements, the MCNP/X Monte Carlo codes will provide designers, operators, and systems analysts with a validated tool for developing state-of-the-art active and passive detection systems. This project is currently in its seventh year (Phase VII). This presentation will review thirty enhancements that have been implemented in MCNPX over the last 3 years and were included in the 2011 release of version 2.7.0. These improvements include 12 physics enhancements, 4 source enhancements, 8 tally enhancements, and 6 other enhancements. Examples and results will be provided for each of these features. The presentation will also discuss the eight enhancements that will be migrated into MCNP6 over the upcoming year.

  1. Effects of confinement on water structure and dynamics and on proton transport: a molecular simulation study

    E-Print Network [OSTI]

    Hirunsit, Pussana

    2009-05-15T23:59:59.000Z

    Classical molecular dynamics (MD) simulations are performed to study structural and dynamic properties of water confined within graphite surfaces. The surfaces are separated at distances varying between 7 and 14.5 and the water density is held...

  2. Atomistic simulation of structure and dynamics of columnar phases of hexabenzocoronene derivatives

    E-Print Network [OSTI]

    Denis Andrienko; Valentina Marcon; Kurt Kremer

    2006-07-27T23:59:59.000Z

    Using atomistic molecular dynamics simulations we study solid and liquid crystalline columnar discotic phases formed by alkyl-substituted hexabenzocoronene mesogens. Correlations between the molecular structure, packing, and dynamical properties of these materials are established.

  3. Design and Evaluation of SOCR Tools for Simulation in Undergraduate Probability and Statistics Courses

    E-Print Network [OSTI]

    Christou, Nicolas; Dinov, Ivo D; Sanchez, Juana

    2007-01-01T23:59:59.000Z

    simulation based applets can enhance students learning,of simulations in relation to the students learning styles.use simulations only for one or the other learning style

  4. A SOFTWARE TOOL TO COMPARE MEASURED AND SIMULATED BUILDING ENERGY PERFORMANCE DATA

    E-Print Network [OSTI]

    Maile, Tobias

    2014-01-01T23:59:59.000Z

    on calibration of building energy simulation programs: Uses,resulting from energy simulations. A detailed analysis ofmore Building Energy Performance Simulation (BEPS) models.

  5. Towards Microsecond Biological Molecular Dynamics Simulations on Hybrid Processors

    SciTech Connect (OSTI)

    Hampton, Scott S [ORNL; Agarwal, Pratul K [ORNL

    2010-01-01T23:59:59.000Z

    Biomolecular simulations continue to become an increasingly important component of molecular biochemistry and biophysics investigations. Performance improvements in the simulations based on molecular dynamics (MD) codes are widely desired. This is particularly driven by the rapid growth of biological data due to improvements in experimental techniques. Unfortunately, the factors, which allowed past performance improvements of MD simulations, particularly the increase in microprocessor clock frequencies, are no longer improving. Hence, novel software and hardware solutions are being explored for accelerating the performance of popular MD codes. In this paper, we describe our efforts to port and optimize LAMMPS, a popular MD framework, on hybrid processors: graphical processing units (GPUs) accelerated multi-core processors. Our implementation is based on porting the computationally expensive, non-bonded interaction terms on the GPUs, and overlapping the computation on the CPU and GPUs. This functionality is built on top of message passing interface (MPI) that allows multi-level parallelism to be extracted even at the workstation level with the multi-core CPUs as well as extend the implementation on GPU clusters. The results from a number of typically sized biomolecular systems are provided and analysis is performed on 3 generations of GPUs from NVIDIA. Our implementation allows up to 30-40 ns/day throughput on a single workstation as well as significant speedup over Cray XT5, a high-end supercomputing platform. Moreover, detailed analysis of the implementation indicates that further code optimization and improvements in GPUs will allow {approx}100 ns/day throughput on workstations and inexpensive GPU clusters, putting the widely-desired microsecond simulation time-scale within reach to a large user community.

  6. Strategies for coupling energy simulation and computational fluid dynamics programs

    E-Print Network [OSTI]

    Zhai, Zhiqiang; Chen, Qingyan; Klems, Joseph H.; Haves, Philip

    2001-01-01T23:59:59.000Z

    2000. EnergyPlus: Energy Simulation Program . ASHRAEA Coupled Airflow-and-Energy Simulation Program for IndoorSTRATEGIES FOR COUPLING ENERGY SIMULATION AND COMPUTATIONAL

  7. Development of an object-oriented dynamics simulator for a LFR DEMO

    SciTech Connect (OSTI)

    Ponciroli, R.; Bortot, S.; Lorenzi, S.; Cammi, A. [Politecnico di Milano, Dept. of Energy, CeSNEF-Nuclear Engineering Div., via Ponzio 34/3, 20133 Milano (Italy)

    2012-07-01T23:59:59.000Z

    A control-oriented dynamics simulator for a Generation IV Lead-cooled Fast Reactor (LFR) demonstrator (DEMO) has been developed aimed at providing a flexible, simple and fast-running tool allowing to perform design-basis transient and stability analyses, and to lay the foundations for the study of the system control strategy. For such purposes, a model representing a compromise between accuracy and straightforwardness has been necessarily sought, and in this view an object-oriented approach based on the Modelica language has been adopted. The reactor primary and secondary systems have been implemented by assembling both component models already available in a specific thermal-hydraulic library, and ad hoc developed nuclear component models suitably modified according to the specific DEMO configuration. The resulting overall plant simulator, incorporating also the balance of plant, consists in the following essential parts: core, integrated steam generator/primary pump block, cold and hot legs, primary coolant cold pool, turbine, heat sink, secondary coolant pump. Afterwards, the reactor response to typical transient initiators has been investigated: feedwater mass flow rate and temperature enhancement, turbine admission valve coefficient variation, increase of primary coolant mass flow rate, and transient of overpower have been simulated; results have been compared with the outcomes of analogous analyses performed by employing a lumped-parameter DEMO plant model. (authors)

  8. Beam dynamics simulations of the NML photoinjector at Fermilab

    SciTech Connect (OSTI)

    Piot, P.; /Fermilab /Northern Illinois U.; Sun, Y.-E.; Church, M.; /Fermilab

    2010-08-01T23:59:59.000Z

    Fermilab is currently constructing a superconducting RF (SRF) test linear accelerator at the New Muon Lab (NML). Besides testing SRF accelerating modules for ILC and Project-X, NML will also eventually support a variety of advanced accelerator R&D experiments. The NML incorporates a 40 MeV photoinjector capable of providing electron bunches with variable parameters. The photoinjector is based on the 1+1/2 cell DESY-type gun followed by two superconducting cavities. It also includes a magnetic bunch compressor, a round-to-flat beam transformer and a low-energy experimental area for beam physics experiments and beam diagnostics R&D. In this paper, we explore, via beam dynamics simulations, the performance of the photoinjector for different operating scenarios.

  9. Experimental simulation of charge conservation violation and Majorana dynamics

    E-Print Network [OSTI]

    R. Keil; C. Noh; A. Rai; S. Sttzer; S. Nolte; D. G. Angelakis; A. Szameit

    2014-04-22T23:59:59.000Z

    Unphysical particles are commonly ruled out from the solution of physical equations, as they fundamentally cannot exist in any real system and, hence, cannot be examined experimentally in a direct fashion. One of the most celebrated equations that allows unphysical solutions is the relativistic Majorana equation\\cite{Majorana} which might describe neutrinos and other exotic particles beyond the Standard Model. The equation's physical solutions, the Majorana fermions, are predicted to be their own anti-particles and as a consequence they have to be neutrally charged; the charged version however (called Majoranon) is, due to charge non-conservation, unphysical and cannot exist. On the other hand, charge conservation violation has been contemplated in alternative theories associated with higher spacetime dimensions or a non-vanishing photon mass; theories whose exotic nature makes experimental testing with current technology an impossible task. In our work, we present an experimental scheme based on optics with which we simulate the dynamics of a Majoranon, involving the implementation of unphysical charge conjugation and complex conjugation. We show that the internal dynamics of the Majoranon is fundamentally different from that of its close cousin, the Dirac particle, to illustrate the nature of the unphysical operations. For this we exploit the fact that in quantum mechanics the wave function itself is not a measurable quantity. Therefore, wave functions of real physical particles, in our case Dirac particles with opposite masses, can be superposed to a wave function of an unphysical particle, the Majoranon. Our results open a new front in the field of quantum simulations of exotic phenomena, with possible applications in condensed matter physics, topological quantum computing, and testing theories within and beyond the Standard Model with existing technology.

  10. IEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 26, NO. 4, NOVEMBER 2011 2285 A Production Simulation Tool for Systems

    E-Print Network [OSTI]

    Gross, George

    uncertainty and variability. I. INTRODUCTION THE growing concern over the impacts of global warming has]. Wind-based electricity production, which incurs no fuel costs and emits no pollution, has becomeIEEE TRANSACTIONS ON POWER SYSTEMS, VOL. 26, NO. 4, NOVEMBER 2011 2285 A Production Simulation Tool

  11. Photoionization analysis of chemo-dynamical dwarf galaxies simulations

    E-Print Network [OSTI]

    Melekh, B; Hensler, G; Buhajenko, O

    2015-01-01T23:59:59.000Z

    Photoionization modelling allows to follow the transport, the emergence, and the absorption of photons taking into account all important processes in nebular plasmas. Such modelling needs the spatial distribution of density, chemical abundances and temperature, that can be provided by chemo-dynamical simulations (ChDS) of dwarf galaxies. We perform multicomponent photoionization modelling (MPhM) of the ionized gas using 2-D ChDSs of dwarf galaxies. We calculate emissivity maps for important nebular emission lines. Their intensities are used to derive the chemical abundance of oxygen by the so-called Te- and R23-methods. Some disagreements are found between oxygen abundances calculated with these methods and the ones coming from the ChDSs. We investigate the fraction of ionizing radiation emitted in the star-forming region which is able to leak out the galaxy. The time- and direction-averaged escape fraction in our simulation is 0.35-0.4. Finally, we have calculated the total Halpha lumi- nosity of our model g...

  12. RECENT PROGRESS IN DYNAMIC PROCESS SIMULATION OF CRYOGENIC REFRIGERATORS

    SciTech Connect (OSTI)

    Kuendig, A. [Linde Kryotechnik AG, Dattlikonerstrasse 5, CH-8422 Pfungen (Switzerland)

    2008-03-16T23:59:59.000Z

    At the CEC 2005 a paper with the title 'Helium refrigerator design for pulsed heat load in Tokamaks' was presented. That paper highlighted the control requirements for cryogenic refrigerators to cope with the expected load variations of future nuclear fusion reactors. First dynamic computer simulations have been presented.In the mean time, the computer program is enhanced and a new series of process simulations are available. The new program considers not only the heat flows and the temperature variations within the heat exchangers, but also the variation of mass flows and pressure drops. The heat transfer numbers now are calculated in dependence of the flow speed and the gas properties. PI-controllers calculate the necessary position of specific valves for maintaining pressures, temperatures and the rotation speed of turbines.Still unsatisfactory is the fact, that changes in the process arrangement usually are attended by adjustments in the program code. It is the main objective of the next step of development a more flexible code which enables that any user defined process arrangements can be assembled by input data.

  13. Enhanced molecular dynamics for simulating porous interphase layers in batteries.

    SciTech Connect (OSTI)

    Zimmerman, Jonathan A.; Wong, Bryan Matthew; Jones, Reese E.; Templeton, Jeremy Alan; Lee, Jonathan (Rice University, Houston, TX)

    2009-10-01T23:59:59.000Z

    Understanding charge transport processes at a molecular level using computational techniques is currently hindered by a lack of appropriate models for incorporating anistropic electric fields in molecular dynamics (MD) simulations. An important technological example is ion transport through solid-electrolyte interphase (SEI) layers that form in many common types of batteries. These layers regulate the rate at which electro-chemical reactions occur, affecting power, safety, and reliability. In this work, we develop a model for incorporating electric fields in MD using an atomistic-to-continuum framework. This framework provides the mathematical and algorithmic infrastructure to couple finite element (FE) representations of continuous data with atomic data. In this application, the electric potential is represented on a FE mesh and is calculated from a Poisson equation with source terms determined by the distribution of the atomic charges. Boundary conditions can be imposed naturally using the FE description of the potential, which then propagates to each atom through modified forces. The method is verified using simulations where analytical or theoretical solutions are known. Calculations of salt water solutions in complex domains are performed to understand how ions are attracted to charged surfaces in the presence of electric fields and interfering media.

  14. Virtual interactive simulation and inspection tool (VISIT) Modeling sensor networks in a virtual city

    SciTech Connect (OSTI)

    Moore, D. M. (David M.)

    2004-01-01T23:59:59.000Z

    The U.S. government is currently investigating the deployment of radiation sensor systems to protect cities against nuclear and radiological threats. Due to the high cost of installing such systems, there is a need to analyze the effectiveness of a variety of sensor configurations in detecting such threats before installing such systems in the field. The Virtual Interactive Simulation and Inspection Tool (VISIT) is a computer program developed for various virtual-reality applications in national security programs, and is presently being adapted to test the efficacy of a variety of sensor configurations in a virtual urban environment. The value of a particular sensor configuration will be assessed by running virtual exercises in which a threat team will choose a radiological device and route to a target and a detection team will specify the locations and types of sensors to be placed in the city to attempt detection of the threat prior to it reaching its target. This paper will discuss the VISIT package, its proposed application, and lessons learned from modeling done to date.

  15. Molecular dynamics simulation studies of structural and dynamical properties of rapidly quenched Al

    SciTech Connect (OSTI)

    Shen, B. [Fudan University; Liu, C. Y. [Zhengzhou University; Jia, Y. [Zhengzhou University; Yue, G. Q. [Fudan University; Ke, F. S. [Fudan University; Zhao, H. B. [Fudan University; Chen, L. Y. [Fudan University; Wang, S. Y. [Ames Laboratory; Wang, Cai-Zhuang [Ames Laboratory; Ho, Kai-Ming [Ames Laboratory

    2013-06-11T23:59:59.000Z

    The structural and dynamical properties of rapidly quenched Al are studied by molecular dynamics simulations. The pair-correlation function of high temperature liquid Al agrees well with the experimental results. Different cooling rates are applied with high cooling rates leading to glass formation, while low cooling rates leading to crystallization. The local structures are characterized by HoneycuttAndersen indices and Voronoi tessellation analysis. The results show that for high cooling rates, the local structures of the liquid and glassy Al are predominated by icosahedral clusters, together with considerable amount of face-centered cubic and hexagonal close packed short-range orders. These short-range order results are further confirmed using the recently developed atomic cluster alignment method. Moreover, the atomic cluster alignment clearly shows the crystal nucleation process in supercooled liquid of Al. Finally, the mean square displacement for the liquid is also analyzed, and the corresponding diffusion coefficient as a function of temperature is calculated.

  16. Molecular dynamics simulations of the elastic properties of polymer/carbon nanotube composites

    E-Print Network [OSTI]

    Elliott, James

    Molecular dynamics simulations of the elastic properties of polymer/carbon nanotube composites Yue composite. However, improvements in properties are by no means guaranteed, and the results are often in the composite. In this paper, we present classical molecular dynamics (MD) simulations of model polymer

  17. A Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    A Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations for architects and HVAC engineers to simulate airflows in and around buildings by Computational Fluid Dynamics Charles R. Broderick III Qingyan Chen Building Technology Program Massachusetts Institute of Technology

  18. A Numerical Model for the Dynamic Simulation of a Recirculation Single-Effect Absorption Chiller

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller is developed. The chiller is driven by two distinct heat sources, includes a custom integrated falling film

  19. Molecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single crystals

    E-Print Network [OSTI]

    Southern California, University of

    films that form on aluminum and aluminum alloys in air protect the surface against further oxidationMolecular dynamics simulations of the nano-scale room-temperature oxidation of aluminum single Abstract The oxidation of aluminum single crystals is studied using molecular dynamics (MD) simulations

  20. EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION

    E-Print Network [OSTI]

    Herbordt, Martin

    EFFICIENT PARTICLE-PAIR FILTERING FOR ACCELERATION OF MOLECULAR DYNAMICS SIMULATION Matt Chiu ABSTRACT The acceleration of molecular dynamics (MD) simulations using high performance reconfigurable: determining the short-range force between particle pairs. In particular, we present the first FPGA study

  1. Coupling of a multizone airflow simulation program with computational fluid dynamics for indoor environmental analysis

    E-Print Network [OSTI]

    Gao, Yang, 1974-

    2002-01-01T23:59:59.000Z

    Current design of building indoor environment comprises macroscopIC approaches, such as CONT AM multizone airflow analysis tool, and microscopic approaches that apply Computational Fluid Dynamics (CFD). Each has certain ...

  2. Abstract--This paper describes a web-based electric power market simulation tool called POWERWEB. It can be used as an

    E-Print Network [OSTI]

    1 Abstract--This paper describes a web-based electric power market simulation tool called POWERWEB structure with the operational and reliability aspects of the underlying power system. Index Terms--Power system economics, power system simulation, software tools. I. INTRODUCTION ODAY's ever evolving power

  3. Study of the HVDC-torsional interactions through digital dynamic simulation

    SciTech Connect (OSTI)

    Padiyar, K.R.; Kothari, A.G.

    1988-01-01T23:59:59.000Z

    This paper presents the detailed dynamic digital simulation for the study of phenomenon of torsional interaction between HVDC-Turbine generator shaft dynamics using the novel converter model. The system model includes detailed representation of the synchronous generator and the shaft dynamics, the ac and dc network transients. The results of a case study indicate the various factors that influence the torsional interaction.

  4. Simulation of dynamics-coupling in piezoelectric tube scanners by reduced order finite element analysis

    E-Print Network [OSTI]

    Fleming, Andrew J.

    and imperfections during the manufactur- ing process of the tube on the dynamics-coupling-caused errors in openSimulation of dynamics-coupling in piezoelectric tube scanners by reduced order finite element as the compensation of dynamics-coupling effects. The present article gives a detailed description of the fully

  5. Simulating Buoyancy-Driven Airflow in Buildings by1 Coarse-Grid Fast Fluid Dynamics2

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    1 Simulating Buoyancy-Driven Airflow in Buildings by1 Coarse-Grid Fast Fluid Dynamics2 Mingang Jin1. Introduction33 Whole-building airflow simulations are required in applications such as natural ventilation34 design, coupled building airflow and energy simulation, smoke control, and air quality diagnosis35

  6. Instabilities in Molecular Dynamics Integrators used in Hybrid Monte Carlo Simulations

    E-Print Network [OSTI]

    B. Joo; UKQCD Collaboration

    2001-10-11T23:59:59.000Z

    We discuss an instability in the leapfrog integration algorithm, widely used in current Hybrid Monte Carlo (HMC) simulations of lattice QCD. We demonstrate the instability in the simple harmonic oscillator (SHO) system where it is manifest. We demonstrate the instability in HMC simulations of lattic QCD with dynamical Wilson-Clover fermions and discuss implications for future simulations of lattice QCD.

  7. Semiclassical Molecular Dynamics Simulations of the Excited State Photodissociation Dynamics of H2O in the A1B1 Band

    E-Print Network [OSTI]

    Wu, Yinghua

    Semiclassical Molecular Dynamics Simulations of the Excited State Photodissociation Dynamics of H2O modeled in terms of classical molecular dynamics simulations.9,12 However, the photodissociation from The photodissociation dynamics of H2O in the A1 B1 band is investigated by implementing a recently developed time

  8. Dynamic simulation of dual-speed wind turbine generation

    SciTech Connect (OSTI)

    Muljadi, E.; Butterfield, C.P.

    1996-10-01T23:59:59.000Z

    Induction generators have been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness, and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using two induction generators with two different rated speeds. With single- speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. The operation at maximum Cp can occur only at a single wind speed. However, if the wind speed varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind-speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative to capture more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine will be investigated. One type of control algorithm for dual- speed operation is proposed. Results from a dynamic simulation will be presented to show how the control algorithm works and how power, current and torque of the system vary as the wind turbine is exposed to varying wind speeds.

  9. Novel morphologies for laterally decorated metaparticles: Molecular dynamics simulation

    E-Print Network [OSTI]

    A. Y. Slyusarchuk; J. M. Ilnytskyi

    2015-01-12T23:59:59.000Z

    We consider a mesoscale model for nano-sized metaparticles (MPs) composed of a central sphere decorated by polymer chains with laterally attached spherocylinder. The latter mimics the mesogenic (e.g., cyanobiphenyl) group. Molecular dynamics simulations of $100$ MPs reveal the existence of two novel morphologies: $\\textrm{uCol}_\\mathrm{h}$ (hexagonal columnar arrangement of MPs with strong uniaxial order of mesogens collinear to the columns axis) and $\\mathrm{wCol}_\\mathrm{h}$ [the same arrangement of MPs but with weak or no liquid crystalline (LC) order]. Collinearity of the LC director and the columnar axis in $\\textrm{uCol}_\\mathrm{h}$ morphology indicates its potentially different opto-mechanical response to an external perturbation as compared to the columnar phase for the terminally attached mesogens. Preliminary analysis of the structures of both phases is performed by studying the order parameters and by visualisation of the MPs arrangements. Different mechanisms for the mesogens reorientation are pointed out for the cases of their terminal and lateral attachment.

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

    E-Print Network [OSTI]

    Ren, Kui

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

  11. Diffusive Dynamics of Water inside Hydrophobic Carbon Micropores Studied by Neutron Spectroscopy and Molecular Dynamics Simulation

    E-Print Network [OSTI]

    S. O. Diallo; L. Vlcek; E. Mamontov; J. K. Keum; Jihua Chen; J. S. Hayes Jr.; A. A. Chialvo

    2014-12-15T23:59:59.000Z

    When water molecules are confined to nanoscale spacings, such as in the nanometer size pores of activated carbon fiber (ACF), their freezing point gets suppressed down to very low temperatures ($\\sim$ 150 K), leading to a metastable liquid state with remarkable physical properties. We have investigated the ambient pressure diffusive dynamics of water in microporous Kynol\\texttrademark ACF-10 (average pore size $\\sim$11.6 {\\AA}, with primarily slit-like pores) from temperature $T=$ 280 K in its stable liquid state down to $T=$ 230 K into the metastable supercooled phase. The observed characteristic relaxation times and diffusion coefficients are found to be respectively higher and lower than those in bulk water, indicating a slowing down of the water mobility with decreasing temperature. The observed temperature-dependent average relaxation time $$ when compared to previous findings indicate that it is the size of the confining pores - not their shape - that primarily affects the dynamics of water for pore sizes larger than 10 {\\AA}. The experimental observations are compared to complementary molecular dynamics simulations of a model system, in which we studied the diffusion of water within the 11.6 {\\AA} gap of two parallel graphene sheets. We find generally a reasonable agreement between the observed and calculated relaxation times at the low momentum transfer $Q$ ($Q\\le 0.9$ \\AA${^{-1}}$). At high $Q$ however, where localized dynamics becomes relevant, this ideal system does not satisfactorily reproduce the measurements. The best agreement is obtained for the diffusion parameter $D$ associated with the hydrogen-site when a representative stretched exponential function, rather than the standard bi-modal exponential model, is used to parameterize the self-correlation function $I(Q,t)$.

  12. Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Horizontal Window Frames with Internal Cavities

    SciTech Connect (OSTI)

    Gustavsen, Arlid; Kohler, Christian; Dalehaug, Arvid; Arasteh, Dariush

    2008-12-01T23:59:59.000Z

    This paper assesses the accuracy of the simplified frame cavity conduction/convection and radiation models presented in ISO 15099 and used in software for rating and labeling window products. Temperatures and U-factors for typical horizontal window frames with internal cavities are compared; results from Computational Fluid Dynamics (CFD) simulations with detailed radiation modeling are used as a reference. Four different frames were studied. Two were made of polyvinyl chloride (PVC) and two of aluminum. For each frame, six different simulations were performed, two with a CFD code and four with a building-component thermal-simulation tool using the Finite Element Method (FEM). This FEM tool addresses convection using correlations from ISO 15099; it addressed radiation with either correlations from ISO 15099 or with a detailed, view-factor-based radiation model. Calculations were performed using the CFD code with and without fluid flow in the window frame cavities; the calculations without fluid flow were performed to verify that the CFD code and the building-component thermal-simulation tool produced consistent results. With the FEM-code, the practice of subdividing small frame cavities was examined, in some cases not subdividing, in some cases subdividing cavities with interconnections smaller than five millimeters (mm) (ISO 15099) and in some cases subdividing cavities with interconnections smaller than seven mm (a breakpoint that has been suggested in other studies). For the various frames, the calculated U-factors were found to be quite comparable (the maximum difference between the reference CFD simulation and the other simulations was found to be 13.2 percent). A maximum difference of 8.5 percent was found between the CFD simulation and the FEM simulation using ISO 15099 procedures. The ISO 15099 correlation works best for frames with high U-factors. For more efficient frames, the relative differences among various simulations are larger. Temperature was also compared, at selected locations on the frames. Small differences was found in the results from model to model. Finally, the effectiveness of the ISO cavity radiation algorithms was examined by comparing results from these algorithms to detailed radiation calculations (from both programs). Our results suggest that improvements in cavity heat transfer calculations can be obtained by using detailed radiation modeling (i.e. view-factor or ray-tracing models), and that incorporation of these strategies may be more important for improving the accuracy of results than the use of CFD modeling for horizontal cavities.

  13. Development of Design and Simulation Tool for Hybrid Geothermal Heat Pump System

    Broader source: Energy.gov [DOE]

    This project will expand Expand eQUEST, a building energy analysis software with latest implementation of DOE-2, for simulations of HGSHP systems and improve its existing simulation capabilities for ordinary GSHP systems.

  14. Path Integral Molecular Dynamics within the Grand Canonical-like Adaptive Resolution Technique: Quantum-Classical Simulation of Liquid Water

    E-Print Network [OSTI]

    Agarwal, Animesh

    2015-01-01T23:59:59.000Z

    Quantum effects due to the spatial delocalization of light atoms are treated in molecular simulation via the path integral technique. Among several methods, Path Integral (PI) Molecular Dynamics (MD) is nowadays a powerful tool to investigate properties induced by spatial delocalization of atoms; however computationally this technique is very demanding. The abovementioned limitation implies the restriction of PIMD applications to relatively small systems and short time scales. One possible solution to overcome size and time limitation is to introduce PIMD algorithms into the Adaptive Resolution Simulation Scheme (AdResS). AdResS requires a relatively small region treated at path integral level and embeds it into a large molecular reservoir consisting of generic spherical coarse grained molecules. It was previously shown that the realization of the idea above, at a simple level, produced reasonable results for toy systems or simple/test systems like liquid parahydrogen. Encouraged by previous results, in this ...

  15. Quantify Water Extraction by TBP/Dodecane via Molecular Dynamics Simulations

    SciTech Connect (OSTI)

    Khomami, Bamin [Univ. of Tennessee, Knoxville, TN (United States); Cui, Shengting [Univ. of Tennessee, Knoxville, TN (United States); de Almeida, Valmor F. [Oak Ridge National Lab., Oak Ridge, TN (United States); Felker, Kevin [Oak Ridge National Lab., Oak Ridge, TN (United States)

    2013-05-16T23:59:59.000Z

    The purpose of this project is to quantify the interfacial transport of water into the most prevalent nuclear reprocessing solvent extractant mixture, namely tri-butyl- phosphate (TBP) and dodecane, via massively parallel molecular dynamics simulations on the most powerful machines available for open research. Specifically, we will accomplish this objective by evolving the water/TBP/dodecane system up to 1 ms elapsed time, and validate the simulation results by direct comparison with experimentally measured water solubility in the organic phase. The significance of this effort is to demonstrate for the first time that the combination of emerging simulation tools and state-of-the-art supercomputers can provide quantitative information on par to experimental measurements for solvent extraction systems of relevance to the nuclear fuel cycle. Results: Initially, the isolated single component, and single phase systems were studied followed by the two-phase, multicomponent counterpart. Specifically, the systems we studied were: pure TBP; pure n-dodecane; TBP/n-dodecane mixture; and the complete extraction system: water-TBP/n-dodecane two phase system to gain deep insight into the water extraction process. We have completely achieved our goal of simulating the molecular extraction of water molecules into the TBP/n-dodecane mixture up to the saturation point, and obtained favorable comparison with experimental data. Many insights into fundamental molecular level processes and physics were obtained from the process. Most importantly, we found that the dipole moment of the extracting agent is crucially important in affecting the interface roughness and the extraction rate of water molecules into the organic phase. In addition, we have identified shortcomings in the existing OPLS-AA force field potential for long-chain alkanes. The significance of this force field is that it is supposed to be optimized for molecular liquid simulations. We found that it failed for dodecane and/or longer chains for this particular solvent extraction application. We have proposed a simple way to circumvent the artificial crystallization of the chains at ambient temperature.

  16. P2VSIM: A SIMULATION AND VISUALIZATION TOOL FOR THE P2V COMPILER

    E-Print Network [OSTI]

    Almeida, Oscar

    2010-07-14T23:59:59.000Z

    not necessarily immediately help in discovering the reasons for the failures. The P2VSim tool presents the ability to combine multiple Verilog signals not only instantaneously, but also across multiple clock cycles, producing a graphical display of the state...

  17. Molecular Dynamics Simulation of the Transport Properties of Molten Transuranic Chloride Salts

    E-Print Network [OSTI]

    Baty, Austin Alan

    2013-02-06T23:59:59.000Z

    are critical to modeling both the neutronics and heat transfer of an ADSMS system. There is a lack of experimental data on the density, heat capacity, electrical and thermal conductivities, and viscosity of TRUCl3 salt systems. Molecular dynamics simulations...

  18. Building Dynamic Models of Service Compositions with Simulation of Provision Resources

    E-Print Network [OSTI]

    Dustdar, Schahram

    Building Dynamic Models of Service Compositions with Simulation of Provision Resources Dragan compositions depends both on the composition structure, and on planning and management of compu- tational resources necessary for provision. Resource constraints on the service provider side have impact

  19. Automotive Research Center (ARC) "The Automotive Research Center (ARC) develops simulation and modeling tools for discovering

    E-Print Network [OSTI]

    Kamat, Vineet R.

    Automotive Research Center (ARC) "The Automotive Research Center (ARC) develops simulation with industry to leverage and transfer the efforts and results http://arc.engin.umich.edu/ #12;

  20. Experimental characterization of energetic material dynamics for multiphase blast simulation.

    SciTech Connect (OSTI)

    Beresh, Steven Jay; Wagner, Justin L.; Kearney, Sean Patrick; Wright, Elton K.; Baer, Melvin R.; Pruett, Brian Owen Matthew

    2011-09-01T23:59:59.000Z

    Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes, which creates one of the largest sources of uncertainty in the simulation of energetic material detonation. To close this gap, a novel Multiphase Shock Tube has been constructed to drive a planar shock wave into a dense gas-solid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 19%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 were achieved. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field. X-Ray diagnostics have been developed to penetrate the opacity of the flow, revealing the concentrations throughout the particle field as it expands and spreads downstream with time. Furthermore, an X-Ray particle tracking velocimetry diagnostic has been demonstrated to be feasible for this flow, which can be used to follow the trajectory of tracer particles seeded into the curtain. Additional experiments on single spherical particles accelerated behind an incident shock wave have shown that elevated particle drag coefficients can be attributed to increased compressibility rather than flow unsteadiness, clarifying confusing results from the historical database of shock tube experiments. The development of the Multiphase Shock Tube and associated diagnostic capabilities offers experimental capability to a previously inaccessible regime, which can provide unprecedented data concerning particle dynamics of dense gas-solid flows.

  1. Simulation of Borehole Resistivity Tools Through Metal Casing at Different Frequencies Using a Goal

    E-Print Network [OSTI]

    Torres-Verdín, Carlos

    the efficiency and accuracy of the method, allowing for high-accuracy simulations of logging instruments-FEM that accurately simulates these logging instruments. This approach is needed to design and predict the behavior, Manuscript received January 20, 2005. This work was supported by the oil-company Baker-Atlas. we provide

  2. Hybrid Electro-Mechanical Simulation Tool for Wind Turbine Generators: Preprint

    SciTech Connect (OSTI)

    Singh, M.; Muljadi, E.; Jonkman, J.

    2013-05-01T23:59:59.000Z

    This paper describes the use of MATLAB/Simulink to simulate the electrical and grid-related aspects of a WTG and the FAST aero-elastic wind turbine code to simulate the aerodynamic and mechanical aspects of the WTG. The combination of the two enables studies involving both electrical and mechanical aspects of the WTG.

  3. To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Herbordt, Martin

    To appear in Journal of Computational Physics Parallel Discrete Molecular Dynamics Simulation and Automated Design Laboratory Department of Electrical and Computer Engineering Boston University; Boston, MA 02215 www.bu.edu/caadlab; email: azkhan@bu.edu, herbordt@bu.edu Abstract: Discrete molecular dynamics

  4. Improvements of Fast Fluid Dynamics for Simulating Airflow in Mingang Jin1

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    in buildings," Numerical Heat Transfer, Part B: Fundamentals, 62(6), 419-438. #12;2 density kinetic viscosity-765-494-0539 Abstract Fast Fluid Dynamics (FFD) could be potentially used for real-time indoor airflow simulations Dynamics (3D FFD).The implementation of boundary conditions at outlet was improved with local mass

  5. Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense Helium

    E-Print Network [OSTI]

    Militzer, Burkhard

    Path Integral Monte Carlo and Density Functional Molecular Dynamics Simulations of Hot, Dense integral Monte Carlo (PIMC) and density func- tional molecular dynamics (DFT-MD), are applied to study hot excitation mecha- nisms that determine their behavior at high temperature. The helium atom has two ionization

  6. Coarse-grained Molecular Dynamics Simulation Approach for Polymer Nano-Composites Rubber

    E-Print Network [OSTI]

    Katsumoto, Shingo

    Coarse-grained Molecular Dynamics Simulation Approach for Polymer Nano-Composites Rubber Katsumi dynamics of entangled long- polymer melts and filled polymer rubber by us- ing coarse-grained model. We of a polymer nano-composite of tire rubber can reproduce almost of feature of the reinforcement effect observed

  7. A continuum-atomistic method for incorporating Joule heating into classical molecular dynamics simulations

    E-Print Network [OSTI]

    Brenner, Donald W.

    binding electronic structure calculations, pertur- bation models, and quantum-classical Hamiltonians [6 depends on the degree of approximation used in solving the electronic structure problem, which can add-scale molecular dynamics (MD) simulation is not to model electron dynamics, but rather to numerically solve

  8. CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade

    E-Print Network [OSTI]

    Tullis, Stephen

    CFD Simulation of Dynamic Thrust and Radial Forces on a Vertical Axis Wind Turbine Blade K. Mc vibration source of a small scale vertical axis wind turbine. The dynamic loading on the blades of the turbine, as they rotate about the central shaft and travel through a range of relative angles of attack

  9. Adsorption of colloidal particles by Brownian dynamics simulation: Kinetics and surface structures

    E-Print Network [OSTI]

    Gray, Jeffrey J.

    Adsorption of colloidal particles by Brownian dynamics simulation: Kinetics and surface structures or nanoscale particulate systems. We develop a new technique for simulating colloidal adsorption processes-limited adsorption. Long-time kinetics fit a 2/3-power law form P. Schaaf, A. Johner, and J. Talbot, Phys. Rev. Lett

  10. Understanding graphene production by ionic surfactant exfoliation: A molecular dynamics simulation study

    E-Print Network [OSTI]

    Simons, Jack

    Understanding graphene production by ionic surfactant exfoliation: A molecular dynamics simulation simulated sodium dodecyl sulfate (SDS) surfactant/water bilayer graphene mixture system to investigate two mechanisms of graphene exfoliation: changing the interlayer distance and sliding away the relative distance

  11. A Simulation Approach to Dynamic Portfolio Choice with an Application to Learning

    E-Print Network [OSTI]

    Stroud, Jonathan

    A Simulation Approach to Dynamic Portfolio Choice with an Application to Learning About Return 2000 This Draft: December 2003 Abstract We present a simulation-based method for solving discrete, parameter and model uncertainty, and learning. We first establish the properties of the method

  12. Large-Scale First-Principles Molecular Dynamics simulations on the BlueGene/L Platform

    E-Print Network [OSTI]

    Franchetti, Franz

    . Keywords Electronic structure. Molecular Dynamics. Ab initio simulations. First-principles simulations of the electronic properties of the system. The electronic structure calculation is the most time-consuming part the past three decades to the development of efficient implementations of the electronic structure

  13. Climate Dynamics Diagnosis of the Marine Low Cloud Simulation in the NCAR Community Earth System

    E-Print Network [OSTI]

    Bretherton, Chris

    -of-the-art coupled atmosphere-ocean models: the NCAR Community Earth System Model (CESM) and the NCEP Global of the Marine Low Cloud Simulation in the NCAR1 Community Earth System Model (CESM) and the NCEP Global2Climate Dynamics Diagnosis of the Marine Low Cloud Simulation in the NCAR Community Earth System

  14. Molecular dynamics simulation of Li surface erosion and bubble formation

    E-Print Network [OSTI]

    Harilal, S. S.

    .49.Sf Keywords: Liquid metal; Lithium; Ion-surface interactions 1. Introduction Bombardment Structure and dynamical properties of liquid Li containing He atoms were studied by the Molecular Dynamics characteristics of light low-energy ions on a liquid Li surface and their diffusion properties have attracted much

  15. Nonadiabatic molecular dynamics simulation: An approach based on quantum measurement picture

    SciTech Connect (OSTI)

    Feng, Wei; Xu, Luting [Department of Physics, Beijing Normal University, Beijing 100875 (China); Li, Xin-Qi, E-mail: lixinqi@bnu.edu.cn [Department of Physics, Beijing Normal University, Beijing 100875 (China); Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Fang, Weihai [Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Department of Chemistry, Beijing Normal University, Beijing 100875 (China); Yan, YiJing [Department of Chemistry, Hong Kong University of Science and Technology, Kowloon (Hong Kong)

    2014-07-15T23:59:59.000Z

    Mixed-quantum-classical molecular dynamics simulation implies an effective quantum measurement on the electronic states by the classical motion of atoms. Based on this insight, we propose a quantum trajectory mean-field approach for nonadiabatic molecular dynamics simulations. The new protocol provides a natural interface between the separate quantum and classical treatments, without invoking artificial surface hopping algorithm. Moreover, it also bridges two widely adopted nonadiabatic dynamics methods, the Ehrenfest mean-field theory and the trajectory surface-hopping method. Excellent agreement with the exact results is illustrated with representative model systems, including the challenging ones for traditional methods.

  16. FORCulator: a micromagnetic tool for simulating first-order reversal curve diagrams

    E-Print Network [OSTI]

    Harrison, Richard J.

    2014-12-05T23:59:59.000Z

    parameters [Dunlop, 2002a, 2002b] can often lead to an ambiguous or misleading assessment of a rocks magnetic mineralogy. FORC diagrams, on the other hand, offer the possibility of unambiguous domain-state fingerprinting, extraction of domain... to geometry-specific signatures in FORC diagrams that inform our understanding of the underlying magnetic mineralogy. 2. FORC Simulation Approaches: Pros and Cons Several methods for simulating FORC diagrams have been successfully employed in the past. Here we...

  17. PARALLEL DYNAMICMESH LAGRANGIAN METHOD FOR SIMULATION FLOWS WITH DYNAMIC INTERFACES

    E-Print Network [OSTI]

    Antaki, James F.

    the aerospace, automotive, biomedical, chemical, marine, materials, wind engineering sciences. These include, material description motion results in dynamic meshes, become hopelessly distorted unless regularly largeamplitude vibrations such flexible aerodynamic components high aspect wings blades; mixtures

  18. Fluidic Catalytic Cracking Power Recovery Dynamic Computer Simulation

    E-Print Network [OSTI]

    Samurin, N. A.

    1980-01-01T23:59:59.000Z

    operation of the primary mechanical components, specifically the axial compressor and hot gas expander. The present work expands upon the steady state model to add the dynamic characteristics of these elements as well as the effects of the controlling...

  19. SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL

    E-Print Network [OSTI]

    AT THE ADOPTION OF HYDROGEN FUEL CELL VEHICLES by Jimena Eyzaguirre M.Sc. Geology, University of Western Ontario, to develop policy-relevant information about dynamics in consumer preferences for hydrogen fuel cell vehicles

  20. Molecular simulations studies of gas adsorption in metalorganic frameworks

    E-Print Network [OSTI]

    Chen, Linjiang

    2014-06-30T23:59:59.000Z

    Using computational tools ranging from molecular simulations including both Monte Carlo and molecular dynamics methods to quantum mechanical (QM) calculations (primarily at density functional theory (DFT) level), ...

  1. A dynamic process model of a natural gas combined cycle -- Model development with startup and shutdown simulations

    SciTech Connect (OSTI)

    Liese, Eric [U.S. DOE; Zitney, Stephen E. [U.S. DOE

    2013-01-01T23:59:59.000Z

    Research in dynamic process simulation for integrated gasification combined cycles (IGCC) with carbon capture has been ongoing at the National Energy Technology Laboratory (NETL), culminating in a full operator training simulator (OTS) and immersive training simulator (ITS) for use in both operator training and research. A derivative work of the IGCC dynamic simulator has been a modification of the combined cycle section to more closely represent a typical natural gas fired combined cycle (NGCC). This paper describes the NGCC dynamic process model and highlights some of the simulators current capabilities through a particular startup and shutdown scenario.

  2. Dynamic Human Reliability Analysis: Benefits and Challenges of Simulating Human Performance

    SciTech Connect (OSTI)

    R. L. Boring

    2007-06-01T23:59:59.000Z

    To date, there has been considerable work on dynamic event trees and other areas related to dynamic probabilistic safety assessment (PSA). The counterpart to these efforts in human reliability analysis (HRA) has centered on the development of specific methods to account for the dynamic nature of human performance. In this paper, the author posits that the key to dynamic HRA is not in the development of specific methods but in the utilization of cognitive modeling and simulation to produce a framework of data that may be used in quantifying the likelihood of human error. This paper provides an overview of simulation approaches to HRA; reviews differences between first, second, and dynamic generation HRA; and outlines potential benefits and challenges of this approach.

  3. A Micro-Grid Simulator Tool (SGridSim) using Effective Node-to-Node Complex Impedance (EN2NCI) Models

    SciTech Connect (OSTI)

    Udhay Ravishankar; Milos manic

    2013-08-01T23:59:59.000Z

    This paper presents a micro-grid simulator tool useful for implementing and testing multi-agent controllers (SGridSim). As a common engineering practice it is important to have a tool that simplifies the modeling of the salient features of a desired system. In electric micro-grids, these salient features are the voltage and power distributions within the micro-grid. Current simplified electric power grid simulator tools such as PowerWorld, PowerSim, Gridlab, etc, model only the power distribution features of a desired micro-grid. Other power grid simulators such as Simulink, Modelica, etc, use detailed modeling to accommodate the voltage distribution features. This paper presents a SGridSim micro-grid simulator tool that simplifies the modeling of both the voltage and power distribution features in a desired micro-grid. The SGridSim tool accomplishes this simplified modeling by using Effective Node-to-Node Complex Impedance (EN2NCI) models of components that typically make-up a micro-grid. The term EN2NCI models means that the impedance based components of a micro-grid are modeled as single impedances tied between their respective voltage nodes on the micro-grid. Hence the benefit of the presented SGridSim tool are 1) simulation of a micro-grid is performed strictly in the complex-domain; 2) faster simulation of a micro-grid by avoiding the simulation of detailed transients. An example micro-grid model was built using the SGridSim tool and tested to simulate both the voltage and power distribution features with a total absolute relative error of less than 6%.

  4. Real-time dynamic simulator for the Topaz II reactor power system

    SciTech Connect (OSTI)

    Kwok, K.S.

    1994-10-01T23:59:59.000Z

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator is a self-contained IBM-PC compatible based system that executes at a speed faster than real-time. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulation of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and causality conditions.

  5. Dynamic Particle Coupling for GPU-based Fluid Simulation

    E-Print Network [OSTI]

    Blanz, Volker

    -vi j 2 W( Pi -Pj ,h). Here pj = k( j - 0) is the pressure with gas constant k and rest density 0 for modeling dynamic particle coupling solely based on individual particle contributions. This technique does and is the fluid viscosity constant. To model the surface tension, Muller et.al. [MCG03] use the so

  6. Dynamic Simulation of Performance Development: Prediction and Optimal Scheduling

    E-Print Network [OSTI]

    Perl, Jürgen

    of Performance Analysis of Sport-e, Volume 4, Number 2. (a) offline analysis (b) online prediction load profile analysis (b) online prediction load profile original performance profile simulated performance profile output depends on load input in different and specific ways. On the one hand, the kinds of load

  7. A quantum simulator for molecules: Imaging molecular orbitals and electronic dynamics with ultracold atoms

    E-Print Network [OSTI]

    Lhmann, Dirk-Sren; Sengstock, Klaus

    2015-01-01T23:59:59.000Z

    In the recent years, ultracold atoms in optical lattices have proven their great value as quantum simulators for studying strongly-correlated phases and complex phenomena in solid-state systems. Here we reveal their potential as quantum simulators for molecular physics and propose a technique to image the three-dimensional molecular orbitals with high resolution. The outstanding tunability of ultracold atoms in terms of potential and interaction offer fully-adjustable model systems for gaining deep insight into the electronic structure of molecules. We study the orbitals of an artificial benzene molecule and discuss the effect of tunable interactions in its conjugated pi electron system with special regard to localization and spin order. The dynamical timescale of ultracold atom simulators are on the order milliseconds which allow for the time-resolved monitoring of a broad range of dynamical processes. As an example, we compute the hole dynamics in the conjugated pi system of the artificial benzene molecule.

  8. Adding quantum effects to the semi-classical molecular dynamics simulations

    E-Print Network [OSTI]

    Yang, Siyang

    2011-01-01T23:59:59.000Z

    Simulating the molecular dynamics (MD) using classical or semi-classical trajectories provides important details for the understanding of many chemical reactions, protein folding, drug design, and solvation effects. MD simulations using trajectories have achieved great successes in the computer simulations of various systems, but it is difficult to incorporate quantum effects in a robust way. Therefore, improving quantum wavepacket dynamics and incorporating nonadiabatic transitions and quantum effects into classical and semi-classical molecular dynamics is critical as well as challenging. In this paper, we present a MD scheme in which a new set of equations of motion (EOM) are proposed to effectively propagate nuclear trajectories while conserving quantum mechanical energy which is critical for describing quantum effects like tunneling. The new quantum EOM is tested on a one-state one-dimensional and a two-state two-dimensional model nonadiabatic systems. The global quantum force experienced by each trajecto...

  9. EnergyGauge USA: A Residential Building Energy Simulation Design Tool

    E-Print Network [OSTI]

    Fairey, P.; Vieira, R. K.; Parker, D. S.; Hanson, B.; Broman, P. A.; Grant, J. B.; Fuehrlein, B.; Gu, L.

    2002-01-01T23:59:59.000Z

    of EnergyGauge USA with significant impact on measures that effect sensible loads. The development of the new correlations is described in Henderson (1998a) and is based on empirical assessment of current generation heating and cooling equipment... moisture capacitance model for the simulation to damp out unrealistic variations in air enthalpy that were observed with the current model. The model, described in Henderson (1998b) assumes that the building has a moisture capacitance that is twenty...

  10. Application of Various HVAC Simulation Programs and Visual Tools to Commissioning

    E-Print Network [OSTI]

    Zheng, M.; Pan, S.

    2007-01-01T23:59:59.000Z

    , aperture size etc., Calculate PAL and BEE Calculate PAL and BEE with BECS,CASBEE Buil- ding Plan/ Design Cx Optimize building location, envelop structure, aperture size, and aperture position etc. Simulate heat load and natural room temperature yearly... peak heat load by using MicroPeak, confirm airflow, thermal environment by CFD Preliminary design Cx Optimize HVAC, heat source, equipment capacity, number division of equipment Calculate hourly heat load through the year in detail Normal...

  11. Calibration and Testing of a Water Model for Simulation of the Molecular Dynamics of Proteins and Nucleic Acids in Solution

    E-Print Network [OSTI]

    Levitt, Michael

    Calibration and Testing of a Water Model for Simulation of the Molecular Dynamics of Proteins important in biological macromolecules, where fewer experimental results are available for calibration. Our

  12. Recovery act: development of design and simulation tool for hybrid geothermal heat pump system

    SciTech Connect (OSTI)

    Wang, Shaojie

    2014-05-29T23:59:59.000Z

    The ground source heat pump (GSHP) system is one of the most energy efficient HVAC technologies in the current market. However, the heat imbalance may degrade the ability of the ground loop heat exchanger (GLHX) to absorb or reject heat. The hybrid GSHP system, which combines a geothermal well field with a supplemental boiler or cooling tower, can balance the loads imposed on the ground loop heat exchangers to minimize its size while retaining superior energy efficiency. This paper presents a recent simulation-based study with an intention to compare multiple common control strategies used in hybrid GSHP systems, including fixed setpoint, outside air reset, load reset, and wetbulb reset. A small office in Oklahoma City conditioned by a hybrid GSHP system was simulated with the latest version of eQUEST 3.7[1]. The simulation results reveal that the hybrid GSHP system has the excellent capability to meet the cooling and heating setpoints during the occupied hours, balance thermal loads on the ground loop, as well as improve the thermal comfort of the occupants with the undersized well field.

  13. Temperature-dependent mechanisms for the dynamics of protein-hydration waters: a molecular dynamics simulation study

    E-Print Network [OSTI]

    Michael Vogel

    2009-02-20T23:59:59.000Z

    Molecular dynamics simulations are performed to study the temperature-dependent dynamics and structures of the hydration shells of elastin-like and collagen-like peptides. For both model peptides, it is consistently observed that, upon cooling, the mechanisms for water dynamics continuously change from small-step diffusive motion to large-step jump motion, the temperature dependence of water dynamics shows a weak crossover from fragile behavior to strong behavior, and the order of the hydrogen-bond network increases. The temperature of the weak crossover from fragile to strong behavior is found to coincide with the temperature at which maximum possible order of the hydrogen-bond network is reached so that the structure becomes temperature independent. In the strong regime, the temperature dependence of water translation and rotational dynamics is characterized by an activation energy of ca. E_a=0.43 eV, consistent with results from previous dielectric spectroscopy and nuclear magnetic resonance studies on protein hydration waters. At these temperatures, a distorted pi-flip motion about the twofold molecular symmetry axes, i.e., a water-specific beta process is an important aspect of water dynamics, at least at the water-peptide interfaces. In addition, it is shown that the hydration waters exhibit pronounced dynamical heterogeneities, which can be traced back to a strong slowdown of water motion in the immediate vicinity of peptide molecules due to formation of water-peptide hydrogen bonds.

  14. Communication An ultrasensitive tool exploiting hydration dynamics to decipher weak lipid

    E-Print Network [OSTI]

    Lee, Ka Yee C.

    membrane interactions, as well as mediate essential lipid membrane functions. ODNP holds much promise as a unique tool titration calorimetry (ITC) [12] have been successfully applied to lipid me

  15. Helmet Streamers with Triple Structures: Simulations of resistive dynamics

    E-Print Network [OSTI]

    T. Wiegelmann; K. Schindler; T. Neukirch

    2008-01-21T23:59:59.000Z

    Recent observations of the solar corona with the LASCO coronagraph on board of the SOHO spacecraft have revealed the occurrence of triple helmet streamers even during solar minimum, which occasionally go unstable and give rise to large coronal mass ejections. There are also indications that the slow solar wind is either a combination of a quasi-stationary flow and a highly fluctuating component or may even be caused completely by many small eruptions or instabilities. As a first step we recently presented an analytical method to calculate simple two-dimensional stationary models of triple helmet streamer configurations. In the present contribution we use the equations of time- dependent resistive magnetohydrodynamics to investigate the stability and the dynamical behaviour of these configurations. We particularly focus on the possible differences between the dynamics of single isolated streamers and triple streamers and on the way in which magnetic reconnection initiates both small scale and large scale dynamical behaviour of the streamers. Our results indicate that small eruptions at the helmet streamer cusp may incessantly accelerate small amounts of plasma without significant changes of the equilibrium configuration and might thus contribute to the non-stationary slow solar wind. On larger time and length scales, large coronal eruptions can occur as a consequence of large scale magnetic reconnection events inside the streamer configuration. Our results also show that triple streamers are usually more stable than a single streamer.

  16. Simulation of aerosol dynamics: a comparative review of mathematical models

    SciTech Connect (OSTI)

    Seigneur, C.; Hudischewskyj, A.B.; Seinfeld, J.H.; Whitby, K.T.; Whitby, E.R.

    1986-01-01T23:59:59.000Z

    Three modeling approaches used are based-continuous, discrete (sectional), and parameterized representations of the aerosol size distribution. Simulations of coagulation and condensation are performed with the three models for clear, hazy, and urban atmospheric conditions. Relative accuracies and computational costs are compared. Reference for the comparison is the continuous approach. The results of the study provide useful information for the selection of an aerosol model, depending on the accuracy requirements and computational constraints associated with a specific application.

  17. Conjugate gradient methods for power system dynamic simulation on parallel computers

    SciTech Connect (OSTI)

    Decker, I.C.; Falcao, D.M.; Kaszkurewicz, E. [COPPE/Federal Univ. of Rio de Janeiro (Brazil)] [COPPE/Federal Univ. of Rio de Janeiro (Brazil)

    1996-08-01T23:59:59.000Z

    Parallel processing is a promising technology for the speedup of the dynamic simulations required in transient stability analysis. In this paper, three methods for dynamic simulation on parallel computers are described and compared. The methods are based on the concepts of spatial and/or time parallelization. In all of them, sets of linear algebraic equations are solved using different versions of Conjugate Gradient methods which have been successfully applied in other scientific and engineering applications. The algorithms presented in the paper were tested in a commercially available parallel computer using an actual large power system model. The results obtained in the tests showed a considerable reduction in computation time.

  18. Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator

    SciTech Connect (OSTI)

    Kwok, K.S.

    1993-11-12T23:59:59.000Z

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

  19. Virtual control system environment: A modeling and simulation tool for process control systems

    SciTech Connect (OSTI)

    Lee, E.; Michalski, J.; Sholander, P.; Van Leeuwen, B. [Sandia National Laboratories, Albuquerque, NM 87111 (United States)

    2006-07-01T23:59:59.000Z

    The development of tools and techniques for security testing and performance testing of Process Control Systems (PCS) is needed since those systems are vulnerable to the same classes of threats as other networked computer systems. In practice, security testing is difficult to perform on operational PCS because it introduces an unacceptable risk of disruption to the critical systems (e.g., power grids) that they control. In addition, the hardware used in PCS is often expensive, making full-scale mockup systems for live experiments impractical. A more flexible approach to these problems can be provided through test beds that provide the proper mix of real, emulated, and virtual elements to model large, complex systems such as critical infrastructures. This paper describes a 'Virtual Control System Environment' that addresses these issues. (authors)

  20. Enabling tools for biological analysis : technologies for the study of protein dynamics, detection and interaction

    E-Print Network [OSTI]

    Anwar, Moshiur Mekhail

    2007-01-01T23:59:59.000Z

    The study of proteins in biological systems requires a comprehensive approach: investigating dynamics, interaction and identification. This thesis will examine several technological approaches we have developed to address ...

  1. Femtosecond photoelectron spectroscopy: a new tool for the study of anion dynamics

    SciTech Connect (OSTI)

    Greenblatt, B.J.

    1999-02-01T23:59:59.000Z

    A new experimental technique for the time-resolved study of anion reactions is presented. Using femtosecond laser pulses, which provide extremely fast ({approx} 100 fs) time resolution, in conjunction with photoelectron spectroscopy, which reveals differences between anion and neutral potential energy surfaces, a complex anion reaction can be followed from its inception through the formation of asymptotic products. Experimental data can be modeled quantitatively using established theoretical approaches, allowing for the refinement of potential energy surfaces as well as dynamical models. After a brief overview, a detailed account of the construction of the experimental apparatus is presented. Documentation of the data acquisition program is contained in the Appendix. The first experimental demonstration of the technique is then presented for I{sub 2}{sup -} photodissociation, modeled using a simulation program which is also detailed in the Appendix. The investigation of I{sub 2}{sup -} photodissociation in several size-selected I{sub 2}{sup -}(Ar){sub n} (n = 6-20) and I{sub 2}{sup -}(CO{sub 2}){sub n} (n = 4-16) clusters forms the heart of the dissertation. In a series of chapters, the numerous effects of solvation on this fundamental bond-breaking reaction are explored, the most notable of which is the recombination of I{sub 2}{sup -} on the ground {tilde X}({sup 2}{Sigma}{sub u}{sup +}) state in sufficiently large clusters. Recombination and trapping of I{sub 2}{sup -} on the excited {tilde A}({sup 2}{Pi}{sub 3/2,g}) state is also observed in both types of clusters. The studies have revealed electronic state transitions, the first step in recombination, on a {approx}500 fs to {approx}10 ps timescale. Accompanying the changes in electronic state is solvent reorganization, which occurs on a similar timescale. Over longer periods ({approx}1 ps to >200 ps), energy is transferred from vibrationally excite d I{sub 2}{sup -} to modes of the solvent, which in turn leads to solvent evaporation. These effects become more important as cluster size increases. In addition, differences in timescale and mechanism are observed between clusters of Ar, which binds to I{sup -} and I{sub 2}{sup -} rather weakly, and CO{sub 2}, whose large quadruple moment allows substantially stronger binding to these anions.

  2. Coupled Dynamic Analysis of Multiple Unit Floating Offshore Wind Turbine

    E-Print Network [OSTI]

    Bae, Yoon Hyeok

    2013-04-23T23:59:59.000Z

    In the present study, a numerical simulation tool has been developed for the rotor-floater-tether coupled dynamic analysis of Multiple Unit Floating Offshore Wind Turbine (MUFOWT) in the time domain including aero-blade-tower dynamics and control...

  3. Coupled Dynamic Analysis of Multiple Unit Floating Offshore Wind Turbine

    E-Print Network [OSTI]

    Bae, Yoon Hyeok

    2013-04-23T23:59:59.000Z

    In the present study, a numerical simulation tool has been developed for the rotor-floater-tether coupled dynamic analysis of Multiple Unit Floating Offshore Wind Turbine (MUFOWT) in the time domain including aero-blade-tower dynamics and control...

  4. Langevin dynamics simulations of biomolecules on graphics processors

    E-Print Network [OSTI]

    A. Zhmurov; R. I. Dima; Y. Kholodov; V. Barsegov

    2010-03-04T23:59:59.000Z

    Due to the very long timescales involved (us-s), theoretical modeling of fundamental biological processes including folding, misfolding, and mechanical unraveling of biomolecules, under physiologically relevant conditions, is challenging even for distributed computing systems. Graphics Processing Units (GPUs) are emerging as an alternative programming platform to the more traditional CPUs as they provide high raw computational power that can be utilized in a wide range of scientific applications. Using a coarse-grained Self Organized Polymer (SOP) model, we have developed and tested the GPU-based implementation of Langevin simulations for proteins (SOP-GPU program). Simultaneous calculation of forces for all particles is implemented using either the particle based or the interacting pair based parallelization, which leads to a ~30-fold acceleration compared to an optimized CPU version of the program. We assess the computational performance of an end-to-end application of the SOP-GPU program, where all steps of the algorithm are running on the GPU, by profiling the associated simulation time and memory usage for a number of small proteins, long protein fibers, and large-size protein assemblies. The SOP-GPU package can now be used in the theoretical exploration of the mechanical properties of large-size protein systems to generate the force-extension and force-indentation profiles under the experimental conditions of force application, and to relate the results of single-molecule experiments in vitro and in silico.

  5. Anomalous Scaling of Structure Functions and Dynamic Constraints on Turbulence Simulations

    E-Print Network [OSTI]

    Victor Yakhot; Katepalli R. Sreenivasan

    2005-06-20T23:59:59.000Z

    The connection between anomalous scaling of structure functions (intermittency) and numerical methods for turbulence simulations is discussed. It is argued that the computational work for direct numerical simulations (DNS) of fully developed turbulence increases as $Re^{4}$, and not as $Re^{3}$ expected from Kolmogorov's theory, where $Re$ is a large-scale Reynolds number. Various relations for the moments of acceleration and velocity derivatives are derived. An infinite set of exact constraints on dynamically consistent subgrid models for Large Eddy Simulations (LES) is derived from the Navier-Stokes equations, and some problems of principle associated with existing LES models are highlighted.

  6. Impact of Resolution on Simulation of Closed Mesoscale Cellular Convection Identified by Dynamically Guided Watershed Segmentation

    SciTech Connect (OSTI)

    Martini, Matus; Gustafson, William I.; Yang, Qing; Xiao, Heng

    2014-11-27T23:59:59.000Z

    Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus that forms in response to a balance between mesoscale dynamics and smaller scale processes such as cloud radiative cooling and microphysics. We use the Weather Research and Forecasting model with chemistry (WRF-Chem) and fully coupled cloud-aerosol interactions to simulate marine low clouds during the VOCALS-REx campaign over the southeast Pacific. A suite of experiments with 3- and 9-km grid spacing indicates resolution-dependent behavior. The simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics we develop a new automated method, which uses a variation of the watershed segmentation technique that combines the detection of cloud boundaries with a test for coincident vertical velocity characteristics. This ensures that the detected cloud fields are dynamically consistent for closed MCC, the most common MCC type over the VOCALS-REx region. We demonstrate that the 3-km simulation is able to reproduce the scaling between horizontal cell size and boundary layer height seen in satellite observations. However, the 9-km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing invariant MCC horizontal scale for all simulated boundary layers depths. The results imply that climate models with grid spacing of roughly 3 km or smaller may be needed to properly simulate the MCC structure in the marine stratocumulus regions.

  7. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    barrier e.g. Heating system options Soft barrier YC YCS oil single systems results to positive soft barrier valuesespecially the soft barriers for central heating systems for

  8. Using dynamic simulations and automated decision tools to design lunar habitats

    E-Print Network [OSTI]

    Kortenkamp, David

    be useful for systems analyses much earlier in the system development life cycle than has previously been-time integrated control in designing and sizing habitat life support systems. The integration of these three implications for general systems analyses and for life support systems. It is likely that transient models

  9. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    Schemes for sustainable energy systems. InternationalPaths to promote Sustainable Energy Systems - The dynamicmoney - for promoting sustainable energy systems - be spent

  10. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    for connection to district heating. Eco-electricityshows a moderate growth of district heating. This is duefor connecting to district heating and for corresponding

  11. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    Development of gas heating technologies, reference scenariodwelling) and defined technology for heating, cooling, DHW,to very technology specific issues, especially of heating

  12. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    strategies, DSM, RES-E, RES-CHP, district heating, bio-and heat production (RES-CHP) and for bio-fuel production.schemes for RUE, RES-E, RES-CHP, and bio-fuels as well as

  13. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    grid comes from waste incineration and CHP. This supportsprimarily form waste incineration and gas CHP, the related

  14. Policy Strategies and Paths to promote Sustainable Energy Systems - The dynamic Invert Simulation Tool

    E-Print Network [OSTI]

    Stadler, Michael; Kranzl, Lukas; Huber, Claus; Haas, Reinhard; Tsioliaridou, Elena

    2006-01-01T23:59:59.000Z

    DSM, RES-E, RES-CHP, district heating, bio- fuels, solarcorresponding E.g. missing district heating grid, in urbanHeating plus DHW) dh district heating connection is in

  15. Exploring the Dynamic Costs of Process-aware Information Systems through Simulation

    E-Print Network [OSTI]

    Ulm, Universität

    Exploring the Dynamic Costs of Process-aware Information Systems through Simulation Bela Mutschler systems, case handling systems) is associated with high costs. Though cost evaluation has received utilizes si- mulation models for investigating costs related to PAIS engineering projects. We motivate

  16. Molecular Simulation of Multistate Peptide Dynamics: A Comparison Between Microsecond Timescale Sampling

    E-Print Network [OSTI]

    Sorin, Eric J.

    , Alberta T2N 1N4, Canada 2 Centre for Biomolecular Interdisciplinary Studies and Industrial ApplicationsMolecular Simulation of Multistate Peptide Dynamics: A Comparison Between Microsecond Timescale energy landscape and the kinetics of the equilibrium is high- lighted by principal component analysis

  17. Molecular Dynamics Simulation of Damage Cascade Formation in Ion Bombarded Solids

    E-Print Network [OSTI]

    Chen, Di

    2012-10-19T23:59:59.000Z

    .......................................................................................................... 10 CHAPTER III MOLECULAR DYNAMICS SIMULATION OF DEFECT... CREATION DUE TO INTERACTIONS OF DAMAGE CASCADE IN SELF ION IRRADIATED SI..........................................................................12 3... ....................................................................................... 14 CHAPTER IV USING CLUSTER ION BOMBARDMENT TO DETERMINE AMORPHIZATION MODE.............................26 4.1 Introduction of Irradiated Amorphization ........................................................... 26 4...

  18. Molecular dynamics simulation of the plastic to triclinic phase transition in clusters of SF6

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    41 Molecular dynamics simulation of the plastic to triclinic phase transition in clusters of SF6 A agrgats n'a pas t entreprise. Abstract. 2014 Clusters of 512 SF6 molecules in their condensed phases of finite systems such as clusters [2]. Liquid sulphur hexafluoride, SF6, forms on cooling what is known

  19. Adaptive Accelerated ReaxFF Reactive Dynamics with Validation from Simulating Hydrogen Combustion

    E-Print Network [OSTI]

    Goddard III, William A.

    Adaptive Accelerated ReaxFF Reactive Dynamics with Validation from Simulating Hydrogen Combustion concept (BB), which we validate here for describing hydrogen combustion. The bond order, undercoordination determined the detailed sequence of reactions for hydrogen combustion with and without the BB. We validate

  20. Precomputed Wave Simulation for Real-Time Sound Propagation of Dynamic Sources in Complex Scenes

    E-Print Network [OSTI]

    North Carolina at Chapel Hill, University of

    Precomputed Wave Simulation for Real-Time Sound Propagation of Dynamic Sources in Complex Scenes of North Carolina at Chapel Hill Abstract We present a method for real-time sound propagation that captures all wave effects, including diffraction and reverberation, for multi- ple moving sources and a moving

  1. Molecular Surgery with Pulsed Electric Fields: Molecular Dynamics Simulations of Nanopore Formation and

    E-Print Network [OSTI]

    Southern California, University of

    Molecular Surgery with Pulsed Electric Fields: Molecular Dynamics Simulations of Nanopore Formation Family Department of Chemical Engineering and Materials Science, Department of Electrical Engineering of water molecules spanning the membrane, decay within a few nanoseconds when the electric field is removed

  2. Molecular dynamics simulations of gold-catalyzed growth of silicon bulk crystals and nanowires

    E-Print Network [OSTI]

    Cai, Wei

    ARTICLES Molecular dynamics simulations of gold-catalyzed growth of silicon bulk crystals of the orientation, yield, and quality of the NWs. Much of the studies on the VLS growth mechanism have been focused. In this article, we present the first set of MD simu- lations of NW growth using this AuSi potential model

  3. Cooling energy demand evaluation by means of regression models obtained from dynamic simulations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Cooling energy demand evaluation by means of regression models obtained from dynamic simulations Ph, Université Lyon1, FRANCE ABSTRACT The forecast of the energy heating/cooling demand would be a good indicator between simple and complex methods of evaluating the cooling energy demand we have proposed to use energy

  4. Interaction potentials for alumina and molecular dynamics simulations of amorphous and liquid alumina

    E-Print Network [OSTI]

    Southern California, University of

    Interaction potentials for alumina and molecular dynamics simulations of amorphous and liquid for preventing crystalliza- tion and giving chemical stability and durability to a glaze, for instance. Due been identified.4 A review of these crystal structures and their pre- cursors can be found in the work

  5. Dynamical chaos and critical behavior in Vlasov simulations of nuclear multifragmentation

    E-Print Network [OSTI]

    A. Atalmi; M. Baldo; G. F. Burgio; A. Rapisarda

    1996-02-26T23:59:59.000Z

    We discuss the presence of both dynamical chaos and signals of a second--order phase transition in numerical Vlasov simulations of nuclear multifragmentation. We find that chaoticity and criticality are strongly related and play a crucial role in the process of fragments formation. This connection is not limited to our model and seems a rather general feature.

  6. Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics simulations

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics of the simulations exhibit non-Fourier heat conduction where the distinct amount of heat is transported in a wavelike called non-Fourier heat conduction equations in order to investigate the applicability

  7. Molecular Dynamics Simulation of Amyloid b Dimer Formation B. Urbanc,* L. Cruz,* F. Ding,*y

    E-Print Network [OSTI]

    Stanley, H. Eugene

    of amyloid plaques. Hence, finding the conformation of these oligo- meric forms of Ab may be important; Thompson, 2003). The most common view is that Ab(140) and Ab(1 42) in fibrils form parallel bMolecular Dynamics Simulation of Amyloid b Dimer Formation B. Urbanc,* L. Cruz,* F. Ding,*y D

  8. Non-adiabatic molecular dynamics simulation of ultrafast solar cell electron transfer

    E-Print Network [OSTI]

    confinement devices [1­5]. Solar cells of the Graetzel type [6,7] are based on dye sensitized nanocrystalline in solar cells, photocatalysis and photoelectrolysis. The electronic structure of the dye cell; Ultrafast electron transfer; Non-adiabatic molecular dynamics simulation; Dye sensitized titanium

  9. Large-scale molecular dynamics simulation of magnetic properties of amorphous iron under pressure

    E-Print Network [OSTI]

    ) Enhanced refrigerant capacity and magnetic entropy flattening using a two-amorphous FeZrB(Cu) compositeLarge-scale molecular dynamics simulation of magnetic properties of amorphous iron under pressure Appl. Phys. Lett. 99, 232501 (2011) Nonlinear motion of magnetic vortex under alternating

  10. The Value of Optimization in Dynamic Ride-Sharing: a Simulation Study in Metro Atlanta

    E-Print Network [OSTI]

    Erera, Alan

    of travelers per vehicle trip by effective usage of empty car seats by ride-sharing may of course enhance, and pollution. Moreover, ride-sharing allows users to share car-related expenses such as fuel costs. 1 #12;ByThe Value of Optimization in Dynamic Ride-Sharing: a Simulation Study in Metro Atlanta Niels Agatz

  11. Building Dynamic Models of Service Compositions With Simulation of Provision Resources

    E-Print Network [OSTI]

    Politécnica de Madrid, Universidad

    Building Dynamic Models of Service Compositions With Simulation of Provision Resources Dragan of service compositions depends both on the composition structure, and on planning and management of compu- tational resources necessary for provision. Resource constraints on the service provider side have impact

  12. A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations

    E-Print Network [OSTI]

    A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations Characterizing and optimizing overall performance of wind plants composed of large numbers at the National Renewable Energy Laboratory (NREL) are coupling physical models of the atmosphere and wind

  13. DYNAMIC SIMULATION OF MONO-TUBE CAVITY RECEIVERS FOR DIRECT STEAM GENERATION

    E-Print Network [OSTI]

    for intended deployment in large arrays of dishes, with steam directed to a central large steam turbine powerDYNAMIC SIMULATION OF MONO-TUBE CAVITY RECEIVERS FOR DIRECT STEAM GENERATION Jos Zapata 1 , John dish has been in operation since 2010 with a mono-tube steam cavity receiver, the SG4 system

  14. Using femtosecond electron pulses as an imaging tool, we can probe ultrafast dynamics by taking snapshots at different time delays. By using femtosecond electron diffraction (FED),

    E-Print Network [OSTI]

    Weston, Ken

    Abstract Using femtosecond electron pulses as an imaging tool, we can probe ultrafast dynamics correlation. Additionally, ultrafast electron shadow imaging (UESI) can explore the dynamics of laser induced System The femtosecond "camera" mentioned above is comprised of an amplified femtosecond pulsed laser

  15. Development and application of chemical tools for investigating dynamic processes in cell migration

    E-Print Network [OSTI]

    Goguen, Brenda Nicole

    2011-01-01T23:59:59.000Z

    Cell migration is a dynamic process essential for many fundamental physiological functions, including wound repair and the immune response. Migration relies on precisely orchestrated events that are regulated in a spatially ...

  16. Electric field induced switching of poly,,ethylene glycol... terminated self-assembled monolayers: A parallel molecular dynamics simulation

    E-Print Network [OSTI]

    Southern California, University of

    : A parallel molecular dynamics simulation Satyavani Vemparala, Rajiv K. Kalia, Aiichiro Nakano, and Priya on the atomistic structure of PEG terminated SAMs using molecular dynamics simulations on parallel computersElectric field induced switching of poly,,ethylene glycol... terminated self-assembled monolayers

  17. Molecular dynamics simulations of coherent optical photon emission from shock waves in Evan J. Reed,1,2,

    E-Print Network [OSTI]

    Soljaèiæ, Marin

    Molecular dynamics simulations of coherent optical photon emission from shock waves in crystals, 013904 2006 . In this work, we present analysis and molecular dynamics simulations of shock waves subject to a shock wave or solitonlike propagating excitation E. J. Reed et al., Phys. Rev. Lett. 96

  18. Ultrafast reaction dynamics in cluster ions: Simulation of the transient photoelectron spectrum of I2 Arn photodissociation

    E-Print Network [OSTI]

    Faeder, Jim

    Hamiltonian model of electronic structure with nonadiabatic molecular dynamics simulations, we calculate of the electronic structure of a manifold of states strongly coupled to the many solvent degrees of freedomUltrafast reaction dynamics in cluster ions: Simulation of the transient photoelectron spectrum

  19. Using regression equations to determine the relative importance of inputs to energy simulation tools

    SciTech Connect (OSTI)

    O'Neill, P.J.; Crawley, D.B.; Schliesing, J.S.

    1991-08-01T23:59:59.000Z

    A set of statistical regression equations was developed to predict relative heating and cooling loads of external zones of commercial buildings. The equations were derived from the coil loads predicted by several thousand DOE-2 simulations. These equations formed the basis for the building envelope criteria in ASHRAE/IES Standard 90.1-1989, Energy Efficient Design of New Commercial Buildings Except Low-Rise Residential Buildings.'' Because these equations predict relative loads, they can be used to determine the relative importance of a broad range of envelope parameters across a variety of climate types. This paper presents the procedure used to develop the equations. The relative importance of all the major loads input variables are discussed for a sample office building, for a broad range of climates. A load sensitivity analysis is then performed, which permits direct comparison of key envelope parameters. The analysis results provide general guidance to DOE-2 users as to the relative importance of specific loads input variables. 6 refs., 8 figs.

  20. The VENUS/NWChem Software Package. Tight Coupling Between Chemical Dynamics Simulations and Electronic Structure Theory

    SciTech Connect (OSTI)

    Lourderaj, Upakarasamy; Sun, Rui; De Jong, Wibe A.; Windus, Theresa L.; Hase, William L.

    2014-03-01T23:59:59.000Z

    The interface for VENUS and NWChem, and the resulting software package for direct dynamics simulations are described. The coupling of the two codes is considered to be a tight coupling. The two codes are compiled and linked together and act as one executable with data being passed between the two codes through routine calls. The advantages of this type of coupling are discussed. The interface has been designed to have as little interference as possible with the core codes of both VENUS and NWChem. VENUS is the code that propagates the direct dynamics trajectories and, therefore, is the program that drives the overall execution of VENUS/NWChem. VENUS has remained an essentially sequential code, which uses the highly parallel structure of NWChem. Subroutines of the interface which accomplish the data transmission and communication between the two computer programs are described. Recent examples of the use of VENUS/NWChem for direct dynamics simulations are summarized.

  1. Extended Rayleigh model of bubble evolution with material strength compared to detailed dynamic simulations

    SciTech Connect (OSTI)

    Glinsky, M.E.; Amendt, P.A.; Bailey, D.S.; London, R.A.; Rubenchik, A.M. [Lawrence Livermore National Lab., CA (United States); Strauss, M. [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1997-03-04T23:59:59.000Z

    The validity of an extended Rayleigh model for laser generated bubbles in soft tissue is examined. This model includes surface tension, viscosity, a realistic water equation of state, material strength and failure, stress wave emission, and linear growth of interface instabilities. It is compared to dynamic simulations using LATIS, which include stress wave propagation, water equation of state, material strength and failure, and viscosity. The model and the simulations are compared using 1-D spherical geometry with bubble in center and a 2-D cylindrical geometry of a laser fiber in water with a bubble formed at the end of the fiber. The model executes over 300x faster on computer than the dynamic simulations.

  2. A parallel algorithm for transient solid dynamics simulations with contact detection

    SciTech Connect (OSTI)

    Attaway, S.; Hendrickson, B.; Plimpton, S.; Gardner, D.; Vaughan, C.; Heinstein, M.; Peery, J.

    1996-06-01T23:59:59.000Z

    Solid dynamics simulations with Lagrangian finite elements are used to model a wide variety of problems, such as the calculation of impact damage to shipping containers for nuclear waste and the analysis of vehicular crashes. Using parallel computers for these simulations has been hindered by the difficulty of searching efficiently for material surface contacts in parallel. A new parallel algorithm for calculation of arbitrary material contacts in finite element simulations has been developed and implemented in the PRONTO3D transient solid dynamics code. This paper will explore some of the issues involved in developing efficient, portable, parallel finite element models for nonlinear transient solid dynamics simulations. The contact-detection problem poses interesting challenges for efficient implementation of a solid dynamics simulation on a parallel computer. The finite element mesh is typically partitioned so that each processor owns a localized region of the finite element mesh. This mesh partitioning is optimal for the finite element portion of the calculation since each processor must communicate only with the few connected neighboring processors that share boundaries with the decomposed mesh. However, contacts can occur between surfaces that may be owned by any two arbitrary processors. Hence, a global search across all processors is required at every time step to search for these contacts. Load-imbalance can become a problem since the finite element decomposition divides the volumetric mesh evenly across processors but typically leaves the surface elements unevenly distributed. In practice, these complications have been limiting factors in the performance and scalability of transient solid dynamics on massively parallel computers. In this paper the authors present a new parallel algorithm for contact detection that overcomes many of these limitations.

  3. Long-time protein folding dynamics from short-time molecular dynamics simulations

    E-Print Network [OSTI]

    Chodera, J D; Swope, W C; Pitera, J W; Dill, Ken A

    2006-01-01T23:59:59.000Z

    On the simulation of protein folding by short time scaleand W. A. Eaton, The protein folding speed limit, Curr.and T. Head-Gordon, Protein folding by distributed computing

  4. Molecular Dynamics Simulations of CO2 Formation in Interstellar Ices

    E-Print Network [OSTI]

    Arasa, Carina; van Dishoeck, Ewine F; Kroes, Geert-Jan

    2013-01-01T23:59:59.000Z

    CO2 ice is one of the most abundant components in ice-coated interstellar ices besides H2O and CO, but the most favorable path to CO2 ice is still unclear. Molecular dynamics calculations on the ultraviolet photodissociation of different kinds of CO-H2O ice systems have been performed at 10 K in order to demonstrate that the reaction between CO and an OH molecule resulting from H2O photodissociation through the first excited state is a possible route to form CO2 ice. However, our calculations, which take into account different ice surface models, suggest that there is another product with a higher formation probability ((3.00+-0.07)x10-2), which is the HOCO complex, whereas the formation of CO2 has a probability of only (3.6+-0.7)x10-4. The initial location of the CO is key to obtain reaction and form CO2: the CO needs to be located deep into the ice. The HOCO complex becomes trapped in the cold ice surface in the trans-HOCO minimum because it quickly loses its internal energy to the surrounding ice, preventi...

  5. Open systems dynamics: Simulating master equations in the computer

    E-Print Network [OSTI]

    Carlos Navarrete-Benlloch

    2015-04-21T23:59:59.000Z

    Master equations are probably the most fundamental equations for anyone working in quantum optics in the presence of dissipation. In this context it is then incredibly useful to have efficient ways of coding and simulating such equations in the computer, and in this notes I try to introduce in a comprehensive way how do I do so, focusing on Matlab, but making it general enough so that it can be directly translated to any other language or software of choice. I inherited most of my methods from Juan Jos\\'{e} Garc\\'{\\i}a-Ripoll (whose numerical abilities I cannot praise enough), changing them here and there to accommodate them to the way my (fairly limited) numerical brain works, and to connect them as much as possible to how I understand the theory behind them. At present, the notes focus on how to code master equations and find their steady state, but I hope soon I will be able to update them with time evolution methods, including how to deal with time-dependent master equations. During the last 4 years I've tested these methods in various different contexts, including circuit quantum electrodynamics, the laser problem, optical parametric oscillators, and optomechanical systems. Comments and (constructive) criticism are greatly welcome, and will be properly credited and acknowledged.

  6. Open systems dynamics: Simulating master equations in the computer

    E-Print Network [OSTI]

    Carlos Navarrete-Benlloch

    2015-04-22T23:59:59.000Z

    Master equations are probably the most fundamental equations for anyone working in quantum optics in the presence of dissipation. In this context it is then incredibly useful to have efficient ways of coding and simulating such equations in the computer, and in this notes I try to introduce in a comprehensive way how do I do so, focusing on Matlab, but making it general enough so that it can be directly translated to any other language or software of choice. I inherited most of my methods from Juan Jos\\'e Garc\\'ia-Ripoll (whose numerical abilities I cannot praise enough), changing them here and there to accommodate them to the way my (fairly limited) numerical brain works, and to connect them as much as possible to how I understand the theory behind them. At present, the notes focus on how to code master equations and find their steady state, but I hope soon I will be able to update them with time evolution methods, including how to deal with time-dependent master equations. During the last 4 years I've tested these methods in various different contexts, including circuit quantum electrodynamics, the laser problem, optical parametric oscillators, and optomechanical systems. Comments and (constructive) criticism are greatly welcome, and will be properly credited and acknowledged.

  7. Particle dynamics in two-dimensional random energy landscapes - experiments and simulations

    E-Print Network [OSTI]

    Florian Evers; Christoph Zunke; Richard D. L. Hanes; Joerg Bewerunge; Imad Ladadwa; Andreas Heuer; Stefan U. Egelhaaf

    2013-06-13T23:59:59.000Z

    The dynamics of individual colloidal particles in random potential energy landscapes were investigated experimentally and by Monte Carlo simulations. The value of the potential at each point in the two-dimensional energy landscape follows a Gaussian distribution. The width of the distribution, and hence the degree of roughness of the energy landscape, was varied and its effect on the particle dynamics studied. This situation represents an example of Brownian dynamics in the presence of disorder. In the experiments, the energy landscapes were generated optically using a holographic set-up with a spatial light modulator, and the particle trajectories were followed by video microscopy. The dynamics are characterized using, e.g., the time-dependent diffusion coefficient, the mean squared displacement, the van Hove function and the non-Gaussian parameter. In both, experiments and simulations, the dynamics are initially diffusive, show an extended sub-diffusive regime at intermediate times before diffusive motion is recovered at very long times. The dependence of the long-time diffusion coefficient on the width of the Gaussian distribution agrees with theoretical predictions. Compared to the dynamics in a one-dimensional potential energy landscape, the localization at intermediate times is weaker and the diffusive regime at long times reached earlier, which is due to the possibility to avoid local maxima in two-dimensional energy landscapes.

  8. Computational Particle Dynamic Simulations on Multicore Processors (CPDMu) Final Report ?? Phase I

    SciTech Connect (OSTI)

    Mark S. Schmalz

    2011-07-24T23:59:59.000Z

    Statement of Problem - Department of Energy has many legacy codes for simulation of computational particle dynamics and computational fluid dynamics applications that are designed to run on sequential processors and are not easily parallelized. Emerging high-performance computing architectures employ massively parallel multicore architectures (e.g., graphics processing units) to increase throughput. Parallelization of legacy simulation codes is a high priority, to achieve compatibility, efficiency, accuracy, and extensibility. General Statement of Solution - A legacy simulation application designed for implementation on mainly-sequential processors has been represented as a graph G. Mathematical transformations, applied to G, produce a graph representation {und G} for a high-performance architecture. Key computational and data movement kernels of the application were analyzed/optimized for parallel execution using the mapping G {yields} {und G}, which can be performed semi-automatically. This approach is widely applicable to many types of high-performance computing systems, such as graphics processing units or clusters comprised of nodes that contain one or more such units. Phase I Accomplishments - Phase I research decomposed/profiled computational particle dynamics simulation code for rocket fuel combustion into low and high computational cost regions (respectively, mainly sequential and mainly parallel kernels), with analysis of space and time complexity. Using the research team's expertise in algorithm-to-architecture mappings, the high-cost kernels were transformed, parallelized, and implemented on Nvidia Fermi GPUs. Measured speedups (GPU with respect to single-core CPU) were approximately 20-32X for realistic model parameters, without final optimization. Error analysis showed no loss of computational accuracy. Commercial Applications and Other Benefits - The proposed research will constitute a breakthrough in solution of problems related to efficient parallel computation of particle and fluid dynamics simulations. These problems occur throughout DOE, military and commercial sectors: the potential payoff is high. We plan to license or sell the solution to contractors for military and domestic applications such as disaster simulation (aerodynamic and hydrodynamic), Government agencies (hydrological and environmental simulations), and medical applications (e.g., in tomographic image reconstruction). Keywords - High-performance Computing, Graphic Processing Unit, Fluid/Particle Simulation. Summary for Members of Congress - Department of Energy has many simulation codes that must compute faster, to be effective. The Phase I research parallelized particle/fluid simulations for rocket combustion, for high-performance computing systems.

  9. Researchers at the National Renewable Energy Laboratory (NREL) develop a new complex modeling and analysis tool

    E-Print Network [OSTI]

    and analysis tool capable of analyzing floating platform concepts for offshore wind turbines. The new modeling tool combines the computational methodologies used to analyze land-based wind turbines dynamic simulation tool will enable the development of cost-effective offshore technologies capable

  10. RAVEN AS A TOOL FOR DYNAMIC PROBABILISTIC RISK ASSESSMENT: SOFTWARE OVERVIEW

    SciTech Connect (OSTI)

    Alfonsi Andrea; Mandelli Diego; Rabiti Cristian; Joshua Cogliati; Robert Kinoshita

    2013-05-01T23:59:59.000Z

    RAVEN is a software tool under development at the Idaho National Laboratory (INL) that acts as the control logic driver and post-processing tool for the newly developed Thermo-Hydraylic code RELAP- 7. The scope of this paper is to show the software structure of RAVEN and its utilization in connection with RELAP-7. A short overview of the mathematical framework behind the code is presented along with its main capabilities such as on-line controlling/monitoring and Monte-Carlo sampling. A demo of a Station Black Out PRA analysis of a simplified Pressurized Water Reactor (PWR) model is shown in order to demonstrate the Monte-Carlo and clustering capabilities.

  11. FORCE FIELDS FOR PROTEIN SIMULATIONS By JAY W. PONDER* AND DAVID A. CASE

    E-Print Network [OSTI]

    Ponder, Jay

    by means of quantum chemistry electronic structure calculations, so most practical simulations use a set, are by now widely used as tools to investigate their structure and dynamics under a wide variety Solvent Models.......................................................... 64 C. Molecular Dynamics

  12. Ab-initio molecular dynamics simulation of liquid water by Quantum Monte Carlo

    E-Print Network [OSTI]

    Andrea Zen; Ye Luo; Guglielmo Mazzola; Leonardo Guidoni; Sandro Sorella

    2015-04-21T23:59:59.000Z

    Although liquid water is ubiquitous in chemical reactions at roots of life and climate on the earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in good agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous Density Functional Theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab-initio simulations of complex chemical systems.

  13. Ab-initio molecular dynamics simulation of liquid water by Quantum Monte Carlo

    E-Print Network [OSTI]

    Andrea Zen; Ye Luo; Guglielmo Mazzola; Leonardo Guidoni; Sandro Sorella

    2014-12-09T23:59:59.000Z

    Despite liquid water is ubiquitous in chemical reactions at roots of life and climate on earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in excellent agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous Density Functional Theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab-initio simulations of complex chemical systems.

  14. SPIN DYNAMIC TOOL DEVELOPMENTS AND STUDY REGARDING THE SuperB PROJECT

    E-Print Network [OSTI]

    Paris-Sud XI, Universit de

    , Long Island, NY, USA U. Wienands, SLAC, Menlo Park, CA, USA Abstract The Zgoubi integrator [1. It is used for simulations of the SuperB storage ring. We present the Zgoubi implementation and the methods. Tracking one particle over one thousand turns with Zgoubi is a matter of one minute. Long term tracking

  15. Integrated Simulation Development and Decision Support Tool-Set for Utility Market and Distributed Solar Power Generation

    SciTech Connect (OSTI)

    Daye, Tony [Green Power Labs

    2013-09-30T23:59:59.000Z

    This project will enable utilities to develop long-term strategic plans that integrate high levels of renewable energy generation, and to better plan power system operations under high renewable penetration. The program developed forecast data streams for decision support and effective integration of centralized and distributed solar power generation in utility operations. This toolset focused on real time simulation of distributed power generation within utility grids with the emphasis on potential applications in day ahead (market) and real time (reliability) utility operations. The project team developed and demonstrated methodologies for quantifying the impact of distributed solar generation on core utility operations, identified protocols for internal data communication requirements, and worked with utility personnel to adapt the new distributed generation (DG) forecasts seamlessly within existing Load and Generation procedures through a sophisticated DMS. This project supported the objectives of the SunShot Initiative and SUNRISE by enabling core utility operations to enhance their simulation capability to analyze and prepare for the impacts of high penetrations of solar on the power grid. The impact of high penetration solar PV on utility operations is not only limited to control centers, but across many core operations. Benefits of an enhanced DMS using state-of-the-art solar forecast data were demonstrated within this project and have had an immediate direct operational cost savings for Energy Marketing for Day Ahead generation commitments, Real Time Operations, Load Forecasting (at an aggregate system level for Day Ahead), Demand Response, Long term Planning (asset management), Distribution Operations, and core ancillary services as required for balancing and reliability. This provided power system operators with the necessary tools and processes to operate the grid in a reliable manner under high renewable penetration.

  16. The dynamic information architecture system : an advanced simulation framework for military and civilian applications.

    SciTech Connect (OSTI)

    Campbell, A. P.; Hummel, J. R.

    1998-01-08T23:59:59.000Z

    DIAS, the Dynamic Information Architecture System, is an object-oriented simulation system that was designed to provide an integrating framework in which new or legacy software applications can operate in a context-driven frame of reference. DIAS provides a flexible and extensible mechanism to allow disparate, and mixed language, software applications to interoperate. DIAS captures the dynamic interplay between different processes or phenomena in the same frame of reference. Finally, DIAS accommodates a broad range of analysis contexts, with widely varying spatial and temporal resolutions and fidelity.

  17. The computer BESK and an early attempt to simulate galactic dynamics

    E-Print Network [OSTI]

    Lindblad, Per Olof

    2015-01-01T23:59:59.000Z

    The first N-body simulation of interacting galaxies, even producing spiral arms, was performed by Erik Holmberg in Lund (1941), not with a numerical computer, but by his arrangement of movable light-bulbs and photocells to measure the luminosity at each bulb and thereby estimate the gravitational force. A decade later, and with the arrival of the first programable computers, computations of galactic dynamics were performed, which were later transferred into a N-body simulation movie. I present here the background details for this work with a description of the important elements to note in the movie which may be retrieved at http://ttt.astro.su.se/~po .

  18. Water harvesting using a conducting polymer: A study by molecular dynamics simulation

    SciTech Connect (OSTI)

    Ostwal, Mayur M.; Sahimi, Muhammad; Tsotsis, Theodore T. [Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211 (United States)

    2009-06-15T23:59:59.000Z

    The results of extensive molecular simulations of adsorption and diffusion of water vapor in polyaniline, made conducting by doping it with HCl or HBr over a broad range of temperatures, are reported. The atomistic model of the polymers was generated using energy minimization, equilibrium molecular dynamics simulations, and two different force fields. The computed sorption isotherms are in excellent agreement with the experimental data. The computed activation energies for the diffusion of water molecules in the polymers also compare well with what has been reported in the literature. The results demonstrate the potential of conducting polyaniline for water harvesting from air.

  19. Probabilistic quantum phase-space simulation of Bell violations and their dynamical evolution

    E-Print Network [OSTI]

    Laura Rosales-Zrate; Bogdan Opanchuk; Peter D. Drummond; Margaret D. Reid

    2014-07-09T23:59:59.000Z

    Quantum simulations of Bell inequality violations are numerically obtained using probabilistic phase space methods, namely the positive P-representation. In this approach the moments of quantum observables are evaluated as moments of variables that have values outside the normal eigenvalue range. There is thus a parallel with quantum weak measurements and weak values. Nevertheless, the representation is exactly equivalent to quantum mechanics. A number of states violating Bell inequalities are sampled, demonstrating that these quantum paradoxes can be treated with probabilistic methods. We treat quantum dynamics by simulating the time evolution of the Bell state formed via parametric down-conversion, and discuss multi-mode generalizations.

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

    E-Print Network [OSTI]

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

  1. A framework for simulating and estimating the state and functional topology of complex dynamic geometric networks

    E-Print Network [OSTI]

    Marius Buibas; Gabriel A. Silva

    2010-06-22T23:59:59.000Z

    We present a framework for simulating signal propagation in geometric networks (i.e. networks that can be mapped to geometric graphs in some space) and for developing algorithms that estimate (i.e. map) the state and functional topology of complex dynamic geometric net- works. Within the framework we define the key features typically present in such networks and of particular relevance to biological cellular neural networks: Dynamics, signaling, observation, and control. The framework is particularly well-suited for estimating functional connectivity in cellular neural networks from experimentally observable data, and has been implemented using graphics processing unit (GPU) high performance computing. Computationally, the framework can simulate cellular network signaling close to or faster than real time. We further propose a standard test set of networks to measure performance and compare different mapping algorithms.

  2. Dynamical consequences of a constraint on the Langevin thermostat in molecular cluster simulation

    SciTech Connect (OSTI)

    Stinson, Jake L.; Kathmann, Shawn M.; Ford, Ian J.

    2014-11-17T23:59:59.000Z

    We investigate some unusual behaviour observed while performing molecular dynamics simulations with the DL_POLY_4.03 code. Under the standard Langevin thermostat, atoms appear to be thermalised to different temperatures, depending on their mass and on the total number of particles in the system. We find that an imposed constraint whereby no thermal noise acts on the centre of mass of the system is the cause of the unexpected behaviour. This is demonstrated by solving the stochastic dynamics for the constrained thermostat and comparing the results with simulation data. The effect of the constraint can be considerable for small systems with disparate masses. By removing the constraint the Langevin thermostat may be restored to its intended behaviour and this has been implemented as an option in DL_POLY_4.05. SMK was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  3. Efficient Molecular Dynamics Simulations of Multiple Radical Center Systems Based on the Fragment Molecular Orbital Method

    SciTech Connect (OSTI)

    Nakata, Hiroya [Tokyo Institute of Technology; Schmidt, Michael W [Ames Laboratory; Fedorov, Dmitri G [National Institute of Advanced Industrial Science and Technology (AIST); Kitaura, Kazuo [Kobe University; Nakamura, Shinichiro [Nakamura Lab; Gordon, Mark S [Ames Laboratory

    2014-10-16T23:59:59.000Z

    The fully analytic energy gradient has been developed and implemented for the restricted open-shell HartreeFock (ROHF) method based on the fragment molecular orbital (FMO) theory for systems that have multiple open-shell molecules. The accuracy of the analytic ROHF energy gradient is compared with the corresponding numerical gradient, illustrating the accuracy of the analytic gradient. The ROHF analytic gradient is used to perform molecular dynamics simulations of an unusual open-shell system, liquid oxygen, and mixtures of oxygen and nitrogen. These molecular dynamics simulations provide some insight about how triplet oxygen molecules interact with each other. Timings reveal that the method can calculate the energy gradient for a system containing 4000 atoms in only 6 h. Therefore, it is concluded that the FMO-ROHF method will be useful for investigating systems with multiple open shells.

  4. Simulation of aerosol dynamics: A comparative review of algorithms used in air quality models

    SciTech Connect (OSTI)

    Zhang, Y.; Seigneur, C.; Seinfeld, J.H.; Jacobson, M.Z.; Binkowski, F.S.

    1999-01-01T23:59:59.000Z

    A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, and gas/particle mass transfer. Two major approaches are used in air quality models to represent the particle size distribution: (1) the sectional approach in which the size distribution is discretized into sections and particle properties are assumed to be constant over particle size sections and (2) the modal approach in which the size distribution is approximated by several modes and particle properties are assumed to be uniform in each mode. The results of this study provide useful information to select algorithms to simulate aerosol dynamics in air quality models and to improve the accuracy of existing algorithms.

  5. SU-E-T-100: Designing a QA Tool for Enhance Dynamic Wedges Based On Dynalog Files

    SciTech Connect (OSTI)

    Yousuf, A; Hussain, A [Department of Oncology, Radiation Oncology, AKUH, Karachi (Pakistan)

    2014-06-01T23:59:59.000Z

    Purpose: A robust quality assurance (QA) program for computer controlled enhanced dynamic wedge (EDW) has been designed and tested. Calculations to perform such QA test is based upon the EDW dynamic log files generated during dose delivery. Methods: Varian record and verify system generates dynamic log (dynalog) files during dynamic dose delivery. The system generated dynalog files contain information such as date and time of treatment, energy, monitor units, wedge orientation, and type of treatment. It also contains the expected calculated segmented treatment tables (STT) and the actual delivered STT for the treatment delivery as a verification record. These files can be used to assess the integrity and precision of the treatment plan delivery. The plans were delivered with a 6 MV beam from a Varian linear accelerator. For available EDW angles (10, 15, 20, 25, 30, 45, and 60) Varian STT values were used to manually calculate monitor units for each segment. It can also be used to calculate the EDW factors. Independent verification of fractional MUs per segment was performed against those generated from dynalog files. The EDW factors used to calculate MUs in TPS were dosimetrically verified in solid water phantom with semiflex chamber on central axis. Results: EDW factors were generated from the STT provided by Varian and verified against practical measurements. The measurements were in agreement of the order of 1 % to the calculated EDW data. Variation between the MUs per segment obtained from dynalog files and those manually calculated was found to be less than 2%. Conclusion: An efficient and easy tool to perform routine QA procedure of EDW is suggested. The method can be easily implemented in any institution without a need for expensive QA equipment. An error of the order of ?2% can be easily detected.

  6. Spin Dynamics Simulations of Multiple Echo Spacing Pulse Sequences in Grossly Inhomogeneous Fields

    SciTech Connect (OSTI)

    Heidler, R.; Bachman, H. N.; Johansen, Y. [Schlumberger Oilfield Services, Sugar Land, TX 77478 (United States)

    2008-12-05T23:59:59.000Z

    Pulse sequences with multiple lengths of echo spacings are used in oilfield NMR logging for diffusion-based NMR applications such as rock and fluid characterization. One specific implementation is the so-called diffusion editing sequence comprising two long echo spacings followed by a standard CPMG at a shorter echo spacing. The echoes in the CPMG portion contain signal from both the direct and stimulated echoes.Modern oilfield NMR logging tools are designed for continuous depth logging of earth formations by projecting both the static (B{sub 0}) and dynamic (B{sub 1}) fields into the formation. Both B{sub 0} and B{sub 1} profiles are grossly inhomogeneous which results in non-steady-state behavior in the early echoes. The spin dynamics effects present a challenge for processing the echo amplitudes to measure porosity (amplitude extrapolated to zero time) and attenuations for fluid or pore size characterization.In this work we describe a calculation of the spin dynamics of the diffusion editing sequence with two long echo spacings. The calculation takes into account full B{sub 1} and B{sub 0} field maps, and comparisons will be made for sensors and parameters typical of oilfield logging tools and environments.

  7. Supplemental Simulation Case Studies of Dynamic Evaporator Modeling Paradigms with Variable Fluid Phases

    E-Print Network [OSTI]

    Rodriguez, E.; Rasmussen, B.

    2015-01-01T23:59:59.000Z

    1Supplemental Simulation Case Studies of Dynamic Evaporator Modeling Paradigms with Variable Fluid Phases Erik Rodriguez1, Bryan Rasmussen2 The purpose of this document is to present a multitude of case studies comparing evaporator modeling... which uses two-phase region density to trigger mass conservative switching. Nine case studies are performed through a combination of three different refrigerants, three different physical system parameters, and three different operating conditions...

  8. Hard discs under steady shear: comparison of Brownian dynamics simulations and mode coupling theory

    E-Print Network [OSTI]

    O. Henrich; F. Weysser; M. E. Cates; M. Fuchs

    2010-01-19T23:59:59.000Z

    Brownian dynamics simulations of bidisperse hard discs moving in two dimensions in a given steady and homogeneous shear flow are presented close to and above the glasstransition density. The stationary structure functions and stresses of shear-melted glass are compared quantitatively to parameter-free numerical calculations of monodisperse hard discs using mode coupling theory within the integration through transients framework. Theory qualitatively explains the properties of the yielding glass but quantitatively overestimatesthe shear-driven stresses and structural anisotropies.

  9. Fast dynamics of an eel-like robot, comparisons with Navier-Stokes simulations

    E-Print Network [OSTI]

    Boyer, Edmond

    the head to the caudal 1 F. Boyer : EMN, IRCCyN, La Chantrerie 4, rue Alfred Kastler B.P. 20722 - 44307Fast dynamics of an eel-like robot, comparisons with Navier-Stokes simulations Frederic Boyer1 Nantes Cedex 3 France. Tel. : +00 33 2 51 85 83 08, Fax : +00 33 2 51 85 83 02, E-mail : frederic.boyer

  10. A Gaussian process-based approach for handling uncertainty in vehicle dynamics simulation.

    SciTech Connect (OSTI)

    Schmitt, K.; Madsen, J.; Anitescu, M.; Negrut, D.; Mathematics and Computer Science; Univ. of Wisconsin at Madison

    2009-01-01T23:59:59.000Z

    Advances in vehicle modeling and simulation in recent years have led to designs that are safer, easier to handle, and less sensitive to external factors. Yet, the potential of simulation is adversely impacted by its limited ability to predict vehicle dynamics in the presence of uncertainty. A commonly occurring source of uncertainty in vehicle dynamics is the road-tire friction interaction, typically represented through a spatially distributed stochastic friction coefficient. The importance of its variation becomes apparent on roads with ice patches, where if the stochastic attributes of the friction coefficient are correctly factored into real time dynamics simulation, robust control strategies could be designed to improve transportation safety. This work concentrates on correctly accounting in the nonlinear dynamics of a car model for the inherent uncertainty in friction coefficient distribution at the road/tire interface. The outcome of this effort is the ability to quantify the effect of input uncertainty on a vehicle's trajectory and the associated escalation of risk in driving. By using a space-dependent Gaussian process, the statistical representation of the friction coefficient allows for consistent space dependence of randomness. The approach proposed allows for the incorporation of noise in the observed data and a nonzero mean for inhomogeneous distribution of the friction coefficient. Based on the statistical model considered, consistent friction coefficient sample distributions are generated over large spatial domains of interest. These samples are subsequently used to compute and characterize the statistics associated with the dynamics of a nonlinear vehicle model. The information concerning the state of the road and thus the friction coefficient is assumed available (measured) at a limited number of points by some sensing device that has a relatively homogeneous noise field (satellite picture or ground sensors, for instance). The methodology proposed can be modified to incorporate information that is sensed by each individual car as it advances along its trajectory.

  11. Using Simulations and kinetic network models to reveal the dynamics and functions of Riboswitches

    E-Print Network [OSTI]

    Jong-Chin Lin; Jeseong Yoon; Changbong Hyeon; D. Thirumalai

    2014-10-02T23:59:59.000Z

    Riboswitches, RNA elements found in the untranslated region, regulate gene expression by binding to target metaboloites with exquisite specificity. Binding of metabolites to the conserved aptamer domain allosterically alters the conformation in the downstream expression platform. The fate of gene expression is determined by the changes in the downstream RNA sequence. As the metabolite-dependent cotranscriptional folding and unfolding dynamics of riboswitches is the key determinant of gene expression, it is important to investigate both the thermodynamics and kinetics of riboswitches both in the presence and absence of metabolite. Single molecule force experiments that decipher the free energy landscape of riboswitches from their mechanical responses, theoretical and computational studies have recently shed light on the distinct mechanism of folding dynamics in different classes of riboswitches. Here we first discuss the dynamics of water around riboswitch, highlighting that water dynamics can enhance the fluctuation of nucleic acid structure. To go beyond native state fluctuations we used the Self-Organized Polymer (SOP) model to predict the dynamics of add adenine riboswitch under mechanical forces. In addition to quantitatively predicting the folding landscape of add-riboswitch our simulations also explain the difference in the dynamics between pbuE adenine- and add adenine-riboswitches. In order to probe the function {\\it in vivo} we use the folding landscape to propose a system level kinetic network model to quantitatively predict how gene expression is regulated for riboswitches that are under kinetic control.

  12. Computer simulation study of surface wave dynamics at the crystal--melt interface

    E-Print Network [OSTI]

    Jorge Benet; Luis G. MacDowell; Eduardo Sanz

    2014-10-01T23:59:59.000Z

    We study, by means of computer simulations, the crystal-melt interface of three different systems: hard-spheres, Lennard Jones and the TIP4P/2005 water model. In particular, we focus on the dynamics of surface waves. We observe that the processes involved in the relaxation of surface waves are characterized by distinct time scales: a slow one related to the continuous recrystallization and melting, that is governed by capillary forces; and a fast one which we suggest to be due to a combination of processes that quickly cause small perturbations to the shape of the interface (like e. g. Rayleigh waves, subdiffusion, or attachment/detachment of particles to/from the crystal). The relaxation of surface waves becomes dominated by the slow process as the wavelength increases. Moreover, we see that the slow relaxation is not influenced by the details of the microscopic dynamics. In a time scale characteristic for the diffusion of the liquid phase, the relaxation dynamics of the crystal-melt interface of water is around one order of magnitude slower than that of Lennard Jones or hard spheres, which we ascribe to the presence of orientational degrees of freedom in the water molecule. Finally, we estimate the rate of crystal growth from our analysis of the capillary wave dynamics and compare it with previous simulation studies and with experiments for the case of water.

  13. The viscosity radius in dilute polymer solutions: Universal behaviour from DNA rheology and Brownian dynamics simulations

    E-Print Network [OSTI]

    Sharadwata Pan; D. Ahirwal; Duc At Nguyen; T. Sridhar; P. Sunthar; J. Ravi Prakash

    2014-10-14T23:59:59.000Z

    The swelling of the viscosity radius, $\\alpha_\\eta$, and the universal viscosity ratio, $U_{\\eta R}$, have been determined experimentally for linear DNA molecules in dilute solutions with excess salt, and numerically by Brownian dynamics simulations, as a function of the solvent quality. In the latter instance, asymptotic parameter free predictions have been obtained by extrapolating simulation data for finite chains to the long chain limit. Experiments and simulations show a universal crossover for $\\alpha_\\eta$ and $U_{\\eta R}$ from $\\theta$ to good solvents in line with earlier observations on synthetic polymer-solvent systems. The significant difference between the swelling of the dynamic viscosity radius from the observed swelling of the static radius of gyration, is shown to arise from the presence of hydrodynamic interactions in the non-draining limit. Simulated values of $\\alpha_\\eta$ and $U_{\\eta R}$ are in good agreement with experimental measurements in synthetic polymer solutions reported previously, and with the measurements in linear DNA solutions reported here.

  14. A localised subgrid scale model for fluid dynamical simulations in astrophysics I: Theory and numerical tests

    E-Print Network [OSTI]

    Schmidt, W; Niemeyer, J C

    2006-01-01T23:59:59.000Z

    We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the sub...

  15. Brushes of flexible, semiflexible and rodlike diblock polyampholytes: Molecular dynamics simulation and scaling analysis

    E-Print Network [OSTI]

    M. Baratlo; H. Fazli

    2009-12-11T23:59:59.000Z

    Planar brushes of flexible, semiflexible and rodlike diblock polyampholytes are studied using molecular dynamics simulations and scaling analysis in a wide range of the grafting density. Simulations show linear dependence of the average thickness on the grafting density for all the brushes regardless of their different equilibrium conformations and different flexibility of anchored chains. Slopes of fitted lines to the average thickness of the brushes of semiflexible and rodlike polyampholytes versus the grafting density are approximately the same and differ considerably from that of the brush of flexible chains. The average thickness of the brush of diblock polyampholytes is also obtained as a function of the grafting density using a simple scaling analysis which is in good agreement with the results of our simulations.

  16. Simulation of polar stratospheric clouds in the specified dynamics version of the whole atmosphere community climate model

    E-Print Network [OSTI]

    Wegner, T.

    We evaluate the simulation of polar stratospheric clouds (PSCs) in the Specified Dynamics version of the Whole Atmosphere Community Climate Model for the Antarctic winter 2005. In this model, PSCs are assumed to form ...

  17. Molecular dynamics simulation of complex molecules at interfaces: dendritic surfactants in clay and amyloid peptides near lipid bilayers

    E-Print Network [OSTI]

    Han, Kunwoo

    2009-06-02T23:59:59.000Z

    We apply a molecular dynamics (MD) simulation technique to complex molecules at interfaces. Partitioning of dendritic surfactants into clay gallery and Ab protein behavior near hydrated lipids are chosen for the purpose. Using a full atomistic model...

  18. The Molecular Structure of a Phosphatidylserine Bilayer Determined by Scattering and Molecular Dynamics Simulations

    SciTech Connect (OSTI)

    Pan, Jianjun [University of South Florida, Tampa (USF)] [University of South Florida, Tampa (USF); Cheng, Xiaolin [ORNL] [ORNL; Monticelli, Luca [Institut National de la Sant et de la Recherche Mdicale (INSERM) and INTS, France] [Institut National de la Sant et de la Recherche Mdicale (INSERM) and INTS, France; Heberle, Frederick A [ORNL] [ORNL; Kucerka, Norbert [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,] [Atomic Energy of Canada Limited (AECL), Canadian Neutron Beam Centre (CNBC) and Comenius University,; Tieleman, D. Peter [University of Calgary, ALberta, Canada] [University of Calgary, ALberta, Canada; Katsaras, John [ORNL] [ORNL

    2014-01-01T23:59:59.000Z

    Phosphatidylserine (PS) lipids play essential roles in biological processes, including enzyme activation and apoptosis. We report on the molecular structure and atomic scale interactions of a fluid bilayer composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS). A scattering density profile model, aided by molecular dynamics (MD) simulations, was developed to jointly refine different contrast small-angle neutron and X-ray scattering data, which yielded a lipid area of 62.7 A2 at 25 C. MD simulations with POPS lipid area constrained at different values were also performed using all-atom and aliphatic united-atom models. The optimal simulated bilayer was obtained using a model-free comparison approach. Examination of the simulated bilayer, which agrees best with the experimental scattering data, reveals a preferential interaction between Na+ ions and the terminal serine and phosphate moieties. Long-range inter-lipid interactions were identified, primarily between the positively charged ammonium, and the negatively charged carboxylic and phosphate oxygens. The area compressibility modulus KA of the POPS bilayer was derived by quantifying lipid area as a function of surface tension from area-constrained MD simulations. It was found that POPS bilayers possess a much larger KA than that of neutral phosphatidylcholine lipid bilayers. We propose that the unique molecular features of POPS bilayers may play an important role in certain physiological functions.

  19. Modeling, simulation, and testing of the mechanical dynamics of and RF MEMS switch.

    SciTech Connect (OSTI)

    Sumali, Hartono; Epp, David S.; Massad, Jordan Elias; Dyck, Christopher William; Starr, Michael James

    2005-07-01T23:59:59.000Z

    Mechanical dynamics can be a determining factor for the switching speed of radio-frequency microelectromechanical systems (RF MEMS) switches. This paper presents the simulation of the mechanical motion of a microswitch under actuation. The switch has a plate suspended by springs. When an electrostatic actuation is applied, the plate moves toward the substrate and closes the switch. Simulations are calculated via a high-fidelity finite element model that couples solid dynamics with electrostatic actuation. It incorporates non-linear coupled dynamics and accommodates fabrication variations. Experimental modal analysis gives results in the frequency domain that verifies the natural frequencies and mode shapes predicted by the model. An effective 1D model is created and used to calculate an actuation voltage waveform that minimizes switch velocity at closure. In the experiment, the switch is actuated with this actuation voltage, and the displacements of the switch at various points are measured using a laser Doppler velocimeter through a microscope. The experiments are repeated on several switches from different batches. The experimental results verify the model.

  20. Spin dynamics simulation of electron spin relaxation in Ni{sup 2+}(aq)

    SciTech Connect (OSTI)

    Rantaharju, Jyrki, E-mail: jjrantaharju@gmail.com; Mare, Ji?, E-mail: jiri.mares@oulu.fi; Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, Oulu, FIN-90014 (Finland)

    2014-07-07T23:59:59.000Z

    The ability to quantitatively predict and analyze the rate of electron spin relaxation of open-shell systems is important for electron paramagnetic resonance and paramagnetic nuclear magnetic resonance spectroscopies. We present a combined molecular dynamics (MD), quantum chemistry (QC), and spin dynamics simulation method for calculating such spin relaxation rates. The method is based on the sampling of a MD trajectory by QC calculations, to produce instantaneous parameters of the spin Hamiltonian used, in turn, to numerically solve the Liouville-von Neumann equation for the time evolution of the spin density matrix. We demonstrate the approach by simulating the relaxation of electron spin in an aqueous solution of Ni{sup 2+} ion. The spin-lattice (T{sub 1}) and spin-spin (T{sub 2}) relaxation rates are extracted directly from the simulations of the time dependence of the longitudinal and transverse magnetization, respectively. Good agreement with the available, indirectly obtained experimental data is obtained by our method.

  1. High-explosive properties from classical molecular dynamics simulations and quantum-chemical computations

    SciTech Connect (OSTI)

    Sewell, T. D. (Thomas D.); Gan, C. K. (Chee Kwan); Jaramillo, E. (Eugenio); Strachan, A. H. (Alejandro H.)

    2004-01-01T23:59:59.000Z

    We are using classical molecular dynamics and condensed phase electronic-structure methods to predict some of the thermophysical and mechanical properties that are needed as input to realistic mesoscale models for plastic-bonded explosives. The main materials studied to date are HMX, PETN, Estane copolymer, and bi(2,2-dinitropropyl) formal/acetal (BDNPF/A). Emphasis is placed on non-reactive properties and thermodynamic states relevant to cookoff and shock initiation phenomena. Both crystal and liquid-state properties are of interest. Typical simulation sizes and times are {approx}10{sup 2} molecules and 2-10 ns, respectively. The overarching goal is to develop internally consistent model thermodynamic and elastic mechanical descriptions for the materials. Prioritization among the set of properties amenable to atomistic simulation is made based on ongoing interactions with mesoscale modelers at Los Alamos and elsewhere. Recent work will be summarized and our view of profitable directions for future research will be discussed, including preliminary results for large-scale molecular dynamics simulations of shock response of crystalline HMX.

  2. Synchronized molecular dynamics simulation via macroscopic heat and momentum transfer: an application to polymer lubrication

    E-Print Network [OSTI]

    Shugo Yasuda; Ryoichi Yamamoto

    2014-07-16T23:59:59.000Z

    The synchronized molecular dynamics simulation via macroscopic heat and momentum transfer is proposed for the non-isothermal flow behaviors of complex fluids. In this method, the molecular dynamics simulations are assigned to small fluid elements to calculate the local stresses and temperatures and are synchronized at certain time intervals to satisfy the macroscopic heat- and momentum- transport equations. This method is applied to the lubrication of a polymeric liquid composed of short chains with ten beads between parallel plates. The rheological properties and conformation of polymer chains coupled with the local viscous heating are investigated with a non-dimensional parameter, i.e., the Nahme-Griffith number, which is defined by the ratio of the viscous heating to the thermal conduction at the characteristic temperature required to sufficiently change the viscosity. The present simulation demonstrates that strong shear thinning and transitional behavior of the conformation of the polymer chains occur with a rapid temperature rise when the Nahme-Griffith number exceeds unity. The results also clarify that the reentrant transition of the linear stress-optical relation occurs for large shear stresses due to the coupling of the conformation of polymer chains and heat generation under shear flows.

  3. An Energy-Aware Simulation Model and Transaction Protocol for Dynamic Workload Distribution in Mobile Ad Hoc Networks1

    E-Print Network [OSTI]

    Pedram, Massoud

    An Energy-Aware Simulation Model and Transaction Protocol for Dynamic Workload Distribution an energy-aware network transaction protocol that dynamically redistributes the computational workload among for detailed evaluation of the performance of different energy management policies in a MANET. Next it presents

  4. Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics Processing Unit

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    Fast and Informative Flow Simulations in a Building by Using Fast Fluid Dynamics Model on Graphics solve Navier-Stokes equations and other transportation equations for energy and species at a speed of 50 it in parallel on a Graphics Processing Unit (GPU). This study validated the FFD on the GPU by simulating

  5. Architectural Improvements and New Processing Tools for the Open XAL Online Model

    SciTech Connect (OSTI)

    Allen, Christopher K [ORNL; Pelaia II, Tom [ORNL; Freed, Jonathan M [ORNL

    2015-01-01T23:59:59.000Z

    The online model is the component of Open XAL providing accelerator modeling, simulation, and dynamic synchronization to live hardware. Significant architectural changes and feature additions have been recently made in two separate areas: 1) the managing and processing of simulation data, and 2) the modeling of RF cavities. Simulation data and data processing have been completely decoupled. A single class manages all simulation data while standard tools were developed for processing the simulation results. RF accelerating cavities are now modeled as composite structures where parameter and dynamics computations are distributed. The beam and hardware models both maintain their relative phase information, which allows for dynamic phase slip and elapsed time computation.

  6. 1 Introduction Petri Nets have been popular as a formalism and practical tool for modelling, simulating and

    E-Print Network [OSTI]

    Lakos, Charles

    1 Introduction Petri Nets have been popular as a formalism and practical tool for modelling of so­called Place­Transition Nets (or PT­nets), enhancements involving the use of coloured tokens and the use of functional languages for net inscriptions can provide powerful tools for specifying concurrent

  7. Leveraging on Easy Java Simulation tool and open source computer simulation library to create interactive digital media for mass customization of high school physics curriculum

    E-Print Network [OSTI]

    Wee, Loo Kang

    2012-01-01T23:59:59.000Z

    This paper highlights the diverse possibilities in the rich community of educators from the Conceptual Learning of Science (CoLoS) and Open Source Physics (OSP) movement to engage, enable and empower educators and students, to create interactive digital media through computer modeling. This concept revolves around a paradigmatic shift towards participatory learning through immersive computer modeling, as opposed to using technology for information transmission. We aim to engage high school educators to professionally develop themselves by creating and customizing simulations possible through Easy Java Simulation (Ejs) and its learning community. Ejs allows educators to be designers of learning environments through modifying source codes of the simulation. Educators can conduct lessons with students' using these interactive digital simulations and rapidly enhance the simulation through changing the source codes personally. Ejs toolkit, its library of simulations and growing community contributed simulation cod...

  8. Quantum molecular dynamics simulation of shock-wave experiments in aluminum

    SciTech Connect (OSTI)

    Minakov, D. V.; Khishchenko, K. V.; Fortov, V. E. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow 125412 (Russian Federation); Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudny, Moscow Region 141700 (Russian Federation); Levashov, P. R. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow 125412 (Russian Federation); Tomsk State University, 36 Lenin Prospekt, Tomsk 634050 (Russian Federation)

    2014-06-14T23:59:59.000Z

    We present quantum molecular dynamics calculations of principal, porous, and double shock Hugoniots, release isentropes, and sound velocity behind the shock front for aluminum. A comprehensive analysis of available shock-wave data is performed; the agreement and discrepancies of simulation results with measurements are discussed. Special attention is paid to the melting region of aluminum along the principal Hugoniot; the boundaries of the melting zone are estimated using the self-diffusion coefficient. Also, we make a comparison with a high-quality multiphase equation of state for aluminum. Independent semiempirical and first-principle models are very close to each other in caloric variables (pressure, density, particle velocity, etc.) but the equation of state gives higher temperature on the principal Hugoniot and release isentropes than ab initio calculations. Thus, the quantum molecular dynamics method can be used for calibration of semiempirical equations of state in case of lack of experimental data.

  9. Spin-lattice dynamics simulation of external field effect on magnetic order of ferromagnetic iron

    SciTech Connect (OSTI)

    Chui, C. P. [Department of Electronic and Information Engineering, the Hong Kong Polytechnic University (Hong Kong)] [Department of Electronic and Information Engineering, the Hong Kong Polytechnic University (Hong Kong); Zhou, Yan, E-mail: yanzhou@hku.hk [Department of Physics, the University of Hong Kong (Hong Kong)] [Department of Physics, the University of Hong Kong (Hong Kong)

    2014-03-15T23:59:59.000Z

    Modeling of field-induced magnetization in ferromagnetic materials has been an active topic in the last dozen years, yet a dynamic treatment of distance-dependent exchange integral has been lacking. In view of that, we employ spin-lattice dynamics (SLD) simulations to study the external field effect on magnetic order of ferromagnetic iron. Our results show that an external field can increase the inflection point of the temperature. Also the model provides a better description of the effect of spin correlation in response to an external field than the mean-field theory. An external field has a more prominent effect on the long range magnetic order than on the short range counterpart. Furthermore, an external field allows the magnon dispersion curves and the uniform precession modes to exhibit magnetic order variation from their temperature dependence.

  10. Numerical simulation of the stochastic dynamics of inclusions in biomembranes in presence of surface tension

    E-Print Network [OSTI]

    H. Rafii-Tabar; H. R. Sepangi

    2005-08-30T23:59:59.000Z

    The stochastic dynamics of inclusions in a randomly fluctuating biomembrane is simulated. These inclusions can represent the embedded proteins and the external particles arriving at a cell membrane. The energetics of the biomembrane is modelled via the Canham-Helfrich Hamiltonian. The contributions of both the bending elastic-curvature energy and the surface tension of the biomembrane are taken into account. The biomembrane is treated as a two-dimensional sheet whose height variations from a reference frame is treated as a stochastic Wiener process. The lateral diffusion parameter associated with this Wiener process coupled with the longitudinal diffusion parameter obtained from the standard Einsteinian diffusion theory completely determine the stochastic motion of the inclusions. It is shown that the presence of surface tension significantly affects the overall dynamics of the inclusions, particularly the rate of capture of the external inclusions, such as drug particles, at the site of the embedded inclusions, such as the embedded proteins.

  11. Solvent-Driven Preferential Association of Lignin with Regions of Crystalline Cellulose in Molecular Dynamics Simulation

    SciTech Connect (OSTI)

    Lindner, Benjamin [ORNL] [ORNL; Petridis, Loukas [ORNL] [ORNL; Schulz, Roland [ORNL] [ORNL; Smith, Jeremy C [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    The precipitation of lignin onto cellulose after pretreatment of lignocellulosic biomass is an obstacle to economically viable cellulosic ethanol production. Here, 750 ns nonequilibrium molecular dynamics simulations are reported of a system of lignin and cellulose in aqueous solution. Lignin is found to strongly associate with itself and the cellulose. However, noncrystalline regions of cellulose are observed to have a lower tendency to associate with lignin than crystalline regions, and this is found to arise from stronger hydration of the noncrystalline chains. The results suggest that the recalcitrance of crystalline cellulose to hydrolysis arises not only from the inaccessibility of inner fibers but also due to the promotion of lignin adhesion.

  12. Analog and digital dynamic simulations of a rigid body aircraft in straight and level flight

    E-Print Network [OSTI]

    Stroman, Morris Michael

    1973-01-01T23:59:59.000Z

    . , Texas A&M University Directed by: Dr. Balusu M. Rao A study of the dynamic response characteristics of an aircraft at low approach speeds was conducted using both a digital and an analog computer to simulate a DeHavilland "Beaver" DHC-2 in flight... to produce more sideslip and yawing motions than the rudder with analytical solutions. The problem areas of the STOL aircraft at low approach speeds as a result of a study of the DeHavilland "Beaver" were in lateral stability. The aircraft's response...

  13. Use of Aria to simulate laser weld pool dynamics for neutron generator production.

    SciTech Connect (OSTI)

    Noble, David R.; Notz, Patrick K.; Martinez, Mario J.; Kraynik, Andrew Michael

    2007-09-01T23:59:59.000Z

    This report documents the results for the FY07 ASC Integrated Codes Level 2 Milestone number 2354. The description for this milestone is, 'Demonstrate level set free surface tracking capabilities in ARIA to simulate the dynamics of the formation and time evolution of a weld pool in laser welding applications for neutron generator production'. The specialized boundary conditions and material properties for the laser welding application were implemented and verified by comparison with existing, two-dimensional applications. Analyses of stationary spot welds and traveling line welds were performed and the accuracy of the three-dimensional (3D) level set algorithm is assessed by comparison with 3D moving mesh calculations.

  14. Entropic measure to prevent energy over-minimization in molecular dynamics simulations

    E-Print Network [OSTI]

    Rydzewski, Jakub; Nowak, Wieslaw

    2015-01-01T23:59:59.000Z

    Geometry optimization via energy minimization is one of the most common steps in computer modelling of biological structures. Nowadays computer power encourage numerous researches to use conjugated gradient minimizations exceeding 1000 steps. However, our research reveals that such over-minimization may lead to thermodynamically unstable conformations. We show that these conformations are not optimum starting points for equilibrium molecular dynamics simulations. We propose a measure based on the Pareto front of total entropy for quality assessment of minimized protein which warrants a proper selection of minimization steps.

  15. Coarse-Grained Molecular Dynamics Simulations of Depletion-Induced Interactions for Soft Matter Systems

    E-Print Network [OSTI]

    Tyler N. Shendruk; Martin Bertrand; James L. Harden; Gary W. Slater; Hendrick W. de Haan

    2014-08-01T23:59:59.000Z

    Given the ubiquity of depletion effects in biological and other soft matter systems, it is desirable to have coarse-grained Molecular Dynamics simulation approaches appropriate for the study of complex systems. This paper examines the use of two common truncated Lennard-Jones (WCA) potentials to describe a pair of colloidal particles in a thermal bath of depletants. The shifted-WCA model is the steeper of the two repulsive potentials considered, while the combinatorial-WCA model is the softer. It is found that the depletion-induced well depth for the combinatorial-WCA model is significantly deeper than the shifted-WCA model because the resulting overlap of the colloids yields extra accessible volume for depletants. For both shifted- and combinatorial-WCA simulations, the second virial coefficients and pair potentials between colloids are demonstrated to be well approximated by the Morphometric Thermodynamics (MT) model. This agreement suggests that the presence of depletants can be accurately modelled in MD simulations by implicitly including them through simple, analytical MT forms for depletion-induced interactions. Although both WCA potentials are found to be effective generic coarse-grained simulation approaches for studying depletion effects in complicated soft matter systems, combinatorial-WCA is the more efficient approach as depletion effects are enhanced at lower depletant densities. The findings indicate that for soft matter systems that are better modelled by potentials with some compressibility, predictions from hard-sphere systems could greatly underestimate the magnitude of depletion effects at a given depletant density.

  16. A localised subgrid scale model for fluid dynamical simulations in astrophysics I: Theory and numerical tests

    E-Print Network [OSTI]

    W. Schmidt; J. C. Niemeyer; W. Hillebrandt

    2006-01-23T23:59:59.000Z

    We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the subgrid scale model in this paper as a basis for more advanced applications in numerical simulations of complex astrophysical phenomena involving turbulence.

  17. Mesoscale simulation of semiflexible chains. I. Endpoint distribution and chain dynamics

    E-Print Network [OSTI]

    Robert D. Groot

    2013-06-06T23:59:59.000Z

    The endpoint distribution and dynamics of semiflexible fibers is studied by numerical simulation. A brief overview is given over the analytical theory of flexible and semiflexible polymers. In particular, a closed expression is given for the relaxation spectrum of wormlike chains, which determines polymer diffusion and rheology. Next a simulation model for wormlike chains with full hydrodynamic interaction is described, and relations for the bending and torsion modulus are given. Two methods are introduced to include torsion stiffness into the model. The model is validated by simulating single chains in a heat bath, and comparing the endpoint distribution of the chains with established Monte Carlo results. It is concluded that torsion stiffness leads to a slightly shorter effective persistence length for a given bending stiffness. To further validate the simulation model, polymer diffusion is studied for fixed persistence length and varying polymer length N. The diffusion constant shows crossover from Rouse to reptation behaviour. The terminal relaxation time obtained from the monomer displacement is consistent with the theory of wormlike chains. The probability for chain crossing has also been studied. This probability is so low that it does not influence the present results.

  18. PuReMD-GPU: A reactive molecular dynamics simulation package for GPUs

    SciTech Connect (OSTI)

    Kylasa, S.B., E-mail: skylasa@purdue.edu [Department of Elec. and Comp. Eng., Purdue University, West Lafayette, IN 47907 (United States); Aktulga, H.M., E-mail: hmaktulga@lbl.gov [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS 50F-1650, Berkeley, CA 94720 (United States); Grama, A.Y., E-mail: ayg@cs.purdue.edu [Department of Computer Science, Purdue University, West Lafayette, IN 47907 (United States)

    2014-09-01T23:59:59.000Z

    We present an efficient and highly accurate GP-GPU implementation of our community code, PuReMD, for reactive molecular dynamics simulations using the ReaxFF force field. PuReMD and its incorporation into LAMMPS (Reax/C) is used by a large number of research groups worldwide for simulating diverse systems ranging from biomembranes to explosives (RDX) at atomistic level of detail. The sub-femtosecond time-steps associated with ReaxFF strongly motivate significant improvements to per-timestep simulation time through effective use of GPUs. This paper presents, in detail, the design and implementation of PuReMD-GPU, which enables ReaxFF simulations on GPUs, as well as various performance optimization techniques we developed to obtain high performance on state-of-the-art hardware. Comprehensive experiments on model systems (bulk water and amorphous silica) are presented to quantify the performance improvements achieved by PuReMD-GPU and to verify its accuracy. In particular, our experiments show up to 16 improvement in runtime compared to our highly optimized CPU-only single-core ReaxFF implementation. PuReMD-GPU is a unique production code, and is currently available on request from the authors.

  19. Driving Down HB-LED Costs: Implementation of Process Simulation Tools and Temperature Control Methods of High Yield MOCVD Growth

    SciTech Connect (OSTI)

    William Quinn

    2012-04-30T23:59:59.000Z

    The overall objective of this multi-faceted program is to develop epitaxial growth systems that meet a goal of 75% (4X) cost reduction in the epitaxy phase of HB-LED manufacture. A 75% reduction in yielded epitaxy cost is necessary in order to achieve the cost goals for widespread penetration of HB-LED??s into back-lighting units (BLU) for LCD panels and ultimately for solid-state lighting (SSL). To do this, the program will address significant improvements in overall equipment Cost of Ownership, or CoO. CoO is a model that includes all costs associated with the epitaxy portion of production. These aspects include cost of yield, capital cost, operational costs, and maintenance costs. We divide the program into three phases where later phases will incorporate the gains of prior phases. Phase one activities are enabling technologies. In collaboration with Sandia National Laboratories we develop a Fluent-compatible chemistry predictive model and a set of mid-infrared and near-ultraviolet pyrometer monitoring tools. Where previously the modeling of the reactor dynamics were studied within FLUENT alone, here, FLUENT and Chemkin are integrated into a comprehensive model of fluid dynamics and the most advanced transport equations developed for Chemkin. Specifically, the Chemkin model offered the key reaction terms for gas-phase nucleation, a key consideration in the optimization of the MOCVD process. This new predictive model is used to design new MOCVD reactors with optimized growth conditions and the newly developed pyrometers are used monitor and control the MOCVD process temperature to within 0.5°C run-to-run and within each wafer. This portion of the grant is in collaboration with partners at Sandia National Laboratories. Phase two activities are continuous improvement projects which extend the current reactor platform along the lines of improved operational efficiency, improved systems control for throughput, and carrier modifications for increased yield. Programmatically, improvements made in Phase I are applied to developments of Phase II when applicable. Phase three is the culmination of the individual tasks from both phases one and two applied to proposed production platforms. We selectively combine previously demonstrated tasks and other options to develop a high-volume production-worthy MOCVD system demonstrating >3x throughput, 1.3x capital efficiency, and 0.7x cost of ownership. In a parallel demonstration we validate the concept of an improved, larger deposition system which utilizes the predictive modeling of chemistry-based flow analysis and extensions of the improvements demonstrated on the current platforms. This validation includes the build and testing of a prototype version of the hardware and demonstration of 69% reduction in the cost of ownership. Also, in this phase we present a stand-alone project to develop a high-temperature system which improves source efficiency by 30% while concurrently increasing growth rate by 1.3x. The material quality is held to the same material quality specifications of our existing baseline processes. The merits of other line item tasks in phase three are discussed for inclusion on next-generation platforms.

  20. GETRAN: A generic, modularly structured computer code for simulation of dynamic behavior of aero- and power generation gas turbine engines

    SciTech Connect (OSTI)

    Schobeiri, M.T.; Attia, M.; Lippke, C. (Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering)

    1994-07-01T23:59:59.000Z

    The design concept, the theoretical background essential for the development of the modularly structured simulation code GETRAN, and several critical simulation cases are presented in this paper. The code being developed under contract with NASA Lewis Research Center is capable of simulating the nonlinear dynamic behavior of single- and multispool core engines, turbofan engines, and power generation gas turbine engines under adverse dynamic operating conditions. The modules implemented into GETRAN correspond to components of existing and new-generation aero- and stationary gas turbine engines with arbitrary configuration and arrangement. For precise simulation of turbine and compressor components, row-by-row diabatic and adiabatic calculation procedures are implemented that account for the specific turbine and compressor cascade, blade geometry, and characteristics. The nonlinear, dynamic behavior of the subject engine is calculated solving a number of systems of partial differential equations, which describe the unsteady behavior of each component individually. To identify each differential equation system unambiguously, special attention is paid to the addressing of each component. The code is capable of executing the simulation procedure at four levels, which increase with the degree of complexity of the system and dynamic event. As representative simulations, four different transient cases with single- and multispool thrust and power generation engines were simulated. These transient cases vary from throttling the exit nozzle area, operation with fuel schedule, rotor speed control, to rotating stall and surge.

  1. Y. Gu, T. VanCourt, M.C. Herbordt / Proc. IEEE Conf. on Field Programmable Logic and Applications (2005) 1 ACCELERATING MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    2005-01-01T23:59:59.000Z

    (2005) 1 ACCELERATING MOLECULAR DYNAMICS SIMULATIONS WITH CONFIGURABLE CIRCUITS Yongfeng Gu Tom Van-space parameter for MD practitioners. 2. MOLECULAR DYNAMICS OVERVIEW Molecular Dynamics simulations generallyCourt Martin C. Herbordt Department of Electrical and Computer Engineering Boston University, Boston, MA 02215

  2. Coarse-grained simulations of vortex dynamics and transition in complex high-Re flows

    SciTech Connect (OSTI)

    Grinstein, Fernando F [Los Alamos National Laboratory

    2011-01-21T23:59:59.000Z

    Turbulent flow complexity in applications in engineering, geophysics and astrophysics typically requires achieving accurate and dependable large scale predictions of highly nonlinear processes with under-resolved computer simulation models. Laboratory observations typically demonstrate the end outcome of complex non-linear three-dimensional physical processes with many unexplained details and mechanisms. Carefully controlled computational experiments based on the numerical solution of the conservation equations for mass, momentum, and energy, provide insights into the underlying flow dynamics. Relevant computational fluid dynamics issues to be addressed relate to the modeling of the unresolved tlow conditions at the subgrid scale (SGS) level - within a computational cell, and at the supergrid (SPG) scale - at initialization and beyond computational boundaries. SGS and SPG information must be prescribed for closure of the equations solved numerically. SGS models appear explicitly or implicitly as additional source tenns in the modified flow equations solved by the numerical solutions being calculated, while SPG models provide the necessary set of initial and boundary conditions that must be prescribed to ensure unique well-posed solutions. From this perspective, it is clear that the simulation process is inherently determined by the SGS and SPG information prescription process. On the other hand, observables in laboratory experiments are always characterized by the finite scales of the instrumental resolution of measuring/visualizing devices, and subject as well to SPG issues. It is thus important to recognize the inherently intrusive nature of observations based on numerical or laboratory experiments. Ultimately, verification and validation (V & V) frameworks and appropriate metrics for the specific problems at hand are needed to establish predictability of the simulation model. Direct numerical simulation (DNS) - resolving all relevant space/time scales, is prohibitively expensive in the foreseeable future for most practical flows of interest at moderate-to-high Reynolds number (Re). On the other end of the simulation spectrum are the Reynolds-Averaged Navier-Stokes (RANS) approaches - which model the turbulent effects. In the coarsegrained large eddy simulation (LES) strategies, the large energy containing structures are resolved, the smaller structures are filtered out, and unresolved SGS effects are modeled. By necessity - rather than choice, LES effectively becomes the intermediate approach between DNS and RANS. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a particular LES denoted implicit LES (ILES), using the class of nonoscillatory finite-volume (NFV) numerical algorithms. Use of the modified equation as framework for theoretical analysis, demonstrates that leading truncation tenns associated with NFV methods provide implicit SGS models of mixed anisotropic type and regularized motion of discrete observables. Tests in fundamental applications ranging from canonical to very complex flows indicate that ILES is competitive with conventional LES in the LES realm proper - flows driven by large scale features. High-Re flows are vortex dominated and governed by short convective timescales compared to those of diffusion, and kinematically characterized at the smallest scales by slender worm vortices with insignificant internal structure. This motivates nominally inviscid ILES methods capable of capturing the high-Re dissipation dynamics and of handling vortices as shocks in shock capturing schemes. Depending on flow regimes, initial conditions, and resolution, additional modeling may be needed to emulate SGS driven physics, such as backscatter, chemical reaction, material mixing, and near-wall flow-dynamics - where typically-intertwined SGS/SPG issues need to be addressed. A major research focus is recognizing when additional explicit models and/or numerical treatments are needed and ensuring that mixed explicit and implicit SGS models can effectively act in

  3. Game-based dynamic simulations supporting technical education and training iJOE International Journal of Online Engineering -www.i-joe.org 1

    E-Print Network [OSTI]

    Foss, Bjarne A.

    . SIMULATIONS AND GAMES FOR LEARNING PURPOSES The development of ICT solutions has allowed for more complex and advanced representations of learning material. In this context, dynamic simulators can be regardedGame-based dynamic simulations supporting technical education and training iJOE International

  4. 3.021J / 1.021J / 10.333J / 18.361J / 22.00J Introduction to Modeling and Simulation, Spring 2011

    E-Print Network [OSTI]

    Buehler, Markus

    This subject provides an introduction to modeling and simulation (IM/S), covering continuum methods, atomistic and molecular simulation (e.g. molecular dynamics) as well as quantum mechanics. These tools play an increasingly ...

  5. A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

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

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-03-20T23:59:59.000Z

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore,moreby integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.less

  6. Study on the thermal resistance in secondary particles chain of silica aerogel by molecular dynamics simulation

    SciTech Connect (OSTI)

    Liu, M. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China); Department of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Qiu, L., E-mail: qiulin111@sina.com, E-mail: jzzhengxinghua@163.com; Zheng, X. H., E-mail: qiulin111@sina.com, E-mail: jzzhengxinghua@163.com; Zhu, J.; Tang, D. W. [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing100190 (China)

    2014-09-07T23:59:59.000Z

    In this article, molecular dynamics simulation was performed to study the heat transport in secondary particles chain of silica aerogel. The two adjacent particles as the basic heat transport unit were modelled to characterize the heat transfer through the calculation of thermal resistance and vibrational density of states (VDOS). The total thermal resistance of two contact particles was predicted by non-equilibrium molecular dynamics simulations (NEMD). The defects were formed by deleting atoms in the system randomly first and performing heating and quenching process afterwards to achieve the DLCA (diffusive limited cluster-cluster aggregation) process. This kind of treatment showed a very reasonable prediction of thermal conductivity for the silica aerogels compared with the experimental values. The heat transport was great suppressed as the contact length increased or defect concentration increased. The constrain effect of heat transport was much significant when contact length fraction was in the small range (<0.5) or the defect concentration is in the high range (>0.5). Also, as the contact length increased, the role of joint thermal resistance played in the constraint of heat transport was increasing. However, the defect concentration did not affect the share of joint thermal resistance as the contact length did. VDOS of the system was calculated by numerical method to characterize the heat transport from atomic vibration view. The smaller contact length and greater defect concentration primarily affected the longitudinal acoustic modes, which ultimately influenced the heat transport between the adjacent particles.

  7. Simulations of the dissociation of small helium clusters with ab initio molecular dynamics in electronically excited states

    SciTech Connect (OSTI)

    Closser, Kristina D.; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Department of Chemistry, University of California Berkeley, Berkeley, California 94720 (United States) [Department of Chemistry, University of California Berkeley, Berkeley, California 94720 (United States); Ultrafast X-Ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Gessner, Oliver [Ultrafast X-Ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Ultrafast X-Ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-04-07T23:59:59.000Z

    The dynamics resulting from electronic excitations of helium clusters were explored using ab initio molecular dynamics. The simulations were performed with configuration interaction singles and adiabatic classical dynamics coupled to a state-following algorithm. 100 different configurations of He{sub 7} were excited into the 2s and 2p manifold for a total of 2800 trajectories. While the most common outcome (90%) was complete fragmentation to 6 ground state atoms and 1 excited state atom, 3% of trajectories yielded bound, He {sub 2}{sup *}, and <0.5% yielded an excited helium trimer. The nature of the dynamics, kinetic energy release, and connections to experiments are discussed.

  8. Development Plan for the Fuel Cycle Simulator

    SciTech Connect (OSTI)

    Brent Dixon

    2011-09-01T23:59:59.000Z

    The Fuel Cycle Simulator (FCS) project was initiated late in FY-10 as the activity to develop a next generation fuel cycle dynamic analysis tool for achieving the Systems Analysis Campaign 'Grand Challenge.' This challenge, as documented in the Campaign Implementation Plan, is to: 'Develop a fuel cycle simulator as part of a suite of tools to support decision-making, communication, and education, that synthesizes and visually explains the multiple attributes of potential fuel cycles.'

  9. Inter-cage dynamics in structure I, II, and H fluoromethane hydrates as studied by NMR and molecular dynamics simulations

    SciTech Connect (OSTI)

    Trueba, Alondra Torres [Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Ontario, K1A 0R6 (Canada); Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Separation Technology Group, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Kroon, Maaike C. [Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Separation Technology Group, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Peters, Cor J. [Eindhoven University of Technology, Department of Chemical Engineering and Chemistry, Separation Technology Group, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); The Petroleum Institute, Chemical Engineering Department, P. O. Box 2533, Abu Dhabi (United Arab Emirates); Moudrakovski, Igor L.; Ratcliffe, Christopher I.; Ripmeester, John A., E-mail: John.Ripmeester@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Ontario, K1A 0R6 (Canada); Alavi, Saman [Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Ontario, K1A 0R6 (Canada); Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada)

    2014-06-07T23:59:59.000Z

    Prospective industrial applications of clathrate hydrates as materials for gas separation require further knowledge of cavity distortion, cavity selectivity, and defects induction by guest-host interactions. The results presented in this contribution show that under certain temperature conditions the guest combination of CH{sub 3}F and a large polar molecule induces defects on the clathrate hydrate framework that allow intercage guest dynamics. {sup 13}C NMR chemical shifts of a CH{sub 3}F/CH{sub 4}/TBME sH hydrate and a temperature analysis of the {sup 2}H NMR powder lineshapes of a CD{sub 3}F/THF sII and CD{sub 3}F/TBME sH hydrate, displayed evidence that the populations of CH{sub 4} and CH{sub 3}F in the D and D{sup ?} cages were in a state of rapid exchange. A hydrogen bonding analysis using molecular dynamics simulations on the TBME/CH{sub 3}F and TBME/CH{sub 4} sH hydrates showed that the presence of CH{sub 3}F enhances the hydrogen bonding probability of the TBME molecule with the water molecules of the cavity. Similar results were obtained for THF/CH{sub 3}F and THF/CH{sub 4} sII hydrates. The enhanced hydrogen bond formation leads to the formation of defects in the water hydrogen bonding lattice and this can enhance the migration of CH{sub 3}F molecules between adjacent small cages.

  10. Dynamic simulations of geologic materials using combined FEM/DEM/SPH analysis

    SciTech Connect (OSTI)

    Morris, J P; Johnson, S M

    2008-03-26T23:59:59.000Z

    An overview of the Lawrence Discrete Element Code (LDEC) is presented, and results from a study investigating the effect of explosive and impact loading on geologic materials using the Livermore Distinct Element Code (LDEC) are detailed. LDEC was initially developed to simulate tunnels and other structures in jointed rock masses using large numbers of polyhedral blocks. Many geophysical applications, such as projectile penetration into rock, concrete targets, and boulder fields, require a combination of continuum and discrete methods in order to predict the formation and interaction of the fragments produced. In an effort to model this class of problems, LDEC now includes implementations of Cosserat point theory and cohesive elements. This approach directly simulates the transition from continuum to discontinuum behavior, thereby allowing for dynamic fracture within a combined finite element/discrete element framework. In addition, there are many application involving geologic materials where fluid-structure interaction is important. To facilitate solution of this class of problems a Smooth Particle Hydrodynamics (SPH) capability has been incorporated into LDEC to simulate fully coupled systems involving geologic materials and a saturating fluid. We will present results from a study of a broad range of geomechanical problems that exercise the various components of LDEC in isolation and in tandem.

  11. Simulation of spray drying in superheated steam using computational fluid dynamics

    SciTech Connect (OSTI)

    Frydman, A.; Vasseur, J.; Ducept, F.; Sionneau, M.; Moureh, J.

    1999-09-01T23:59:59.000Z

    This paper presents a numerical simulation and experimental validation of a spray dryer using superheated steam instead of air as drying medium, modeled with a computational fluid dynamics (CFD) code. The model describes momentum, heat and mass transfer between two phases--a discrete phase of droplets, and a continuous gas phase--through a finite volume method. For the simulation, droplet size distribution is represented by 6 discrete classes of diameter, fitting to the experimental distribution injected from the nozzle orifice, taking into account their peculiar shrinkage during drying. This model is able to predict the most important features of the dryer: fields of gas temperature and gas velocity inside the chamber, droplets trajectories and eventual deposits on to the wall. The results of simulation are compared to a pilot scale dryer, using water. In the absence of risk of power ignition in steam, the authors have tested rather high steam inlet temperature (973K), thus obtaining a high volumic efficiency. The model is validated by comparison between experimental and predicted values of temperature inside the chamber, verifying the coupling between the 3 different types of transfer without adjustment. This type of model can be used for chamber design, or scale up. Using superheated steam instead of air in a spray dryer can allow a high volumic evaporation rate (20 k.h.m{sup 3}), high energy recovery and better environment control.

  12. Simulation of wireline sonic logging measurements acquired with BoreholeEccentered tools using a high-order adaptive

    E-Print Network [OSTI]

    Torres-Verdn, Carlos

    Torres-Verdn b , Angel Mora d , Victor M. Calo d a Department of Applied Mathematics, Statistics) for truncation of the computational domain. The simulation method was verified for various model problems. A similar method was successfully applied to simulate induction and laterolog resistivity measurements

  13. Simulation of dynamic fracture using peridynamics, finite element modeling, and contact.

    SciTech Connect (OSTI)

    Littlewood, David John

    2010-11-01T23:59:59.000Z

    Peridynamics is a nonlocal extension of classical solid mechanics that allows for the modeling of bodies in which discontinuities occur spontaneously. Because the peridynamic expression for the balance of linear momentum does not contain spatial derivatives and is instead based on an integral equation, it is well suited for modeling phenomena involving spatial discontinuities such as crack formation and fracture. In this study, both peridynamics and classical finite element analysis are applied to simulate material response under dynamic blast loading conditions. A combined approach is utilized in which the portion of the simulation modeled with peridynamics interacts with the finite element portion of the model via a contact algorithm. The peridynamic portion of the analysis utilizes an elastic-plastic constitutive model with linear hardening. The peridynamic interface to the constitutive model is based on the calculation of an approximate deformation gradient, requiring the suppression of possible zero-energy modes. The classical finite element portion of the model utilizes a Johnson-Cook constitutive model. Simulation results are validated by direct comparison to expanding tube experiments. The coupled modeling approach successfully captures material response at the surface of the tube and the emerging fracture pattern. The coupling of peridynamics and finite element analysis via a contact algorithm has been shown to be a viable means for simulating material fracture in a high-velocity impact experiment. A combined peridynamics/finite element approach was applied to model an expanding tube experiment performed by Vogler, et al., in which loading on the tube is a result of Lexan slugs impacting inside the tube. The Lexan portion of the simulation was modeled with finite elements and a Johnson-Cook elastic-plastic material model in conjunction with an equation-of-state law. The steel tube portion of the simulation was modeled with peridynamics, an elastic-plastic material model, and a critical stretch bond damage model. The application of peridynamics to the tube portion of the model allowed the capture of the formation of cracks and eventual fragmentation of the tube. The simulation results yielded good agreement with the experimental results published by Vogler, et al., for the velocity and displacement profiles on the surface of the tube and the resulting fragment distribution. Numerical difficulties were encountered that required removal of hexahedron elements from the Lexan portion of the model over the course of the simulation. The significant number of inverted and nearly-inverted elements appearing over the course of the simulation is believed to be a result of irregularities in the contact between the Lexan and AerMet portions of the model, and was likely exacerbated by the ultra-high strength of the AerMet tube. Future simulations are planned in which the Lexan portion of the simulation is modeled with peridynamics, or with an alternative method such as smoothed particle hydrodynamics, with the goal of reducing these numerical difficulties.

  14. Simulation studies of slow dynamics of hydration water in lysozyme : hydration level dependence and comparison with experiment using new time domain analysis

    E-Print Network [OSTI]

    Kim, Chansoo, S.M. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    A series of Molecular Dynamics (MD) simulations using the GROMACS package has been performed in this thesis. It is used to mimic and simulate the hydration water in Lysozyme with three different hydration levels (h = 0.3, ...

  15. A comparison of crystalline and molten structures of zirconolite (CaZrTi?O?), a potential plutonium wasteform medium, by molecular dynamics simulation and topological analysis

    E-Print Network [OSTI]

    Rich, Sarah Celeste

    2008-01-01T23:59:59.000Z

    Molecular dynamics simulations of the ceramic compound zirconolite (CaZrTi?O?), a potential crystalline wasteform host for plutonium, were carried out for ideal and experimental crystalline forms and a simulated molten ...

  16. Deployment of a Suite of High-Performance Computational Tools for Multi-scale Multi-physics Simulation of Generation IV Reactors

    SciTech Connect (OSTI)

    Podowski, Michael Z

    2013-01-03T23:59:59.000Z

    The overall objective of this project has been to deploy advanced simulation capabilities for next generation reactor systems utilizing newly available, high-performance computing facilities. The approach includes the following major components: The development of new simulation capabilities using state-of-the-art computer codes of different scales: molecular dynamics (MD) level, DNS (FronTier and PHASTA) and CFD (NPHASE-CMFD); The development of advanced numerical solvers for large-size computational problems; The deployment of a multiple-code computational platform for multiscale simulations of gas/liquid two-phase flow during reactor transients and accidents; and Application of the new computational methodology to study the progression of loss-of-flow accident in sodium fast reactor (SFR).

  17. Development of EEM based siliconwater and silicawater wall potentials for non-reactive molecular dynamics simulations

    SciTech Connect (OSTI)

    Kim, Junghan; Iype, Eldhose; Frijns, Arjan J.H.; Nedea, Silvia V.; Steenhoven, Anton A. van

    2014-07-01T23:59:59.000Z

    Molecular dynamics simulations of heat transfer in gases are computationally expensive when the wall molecules are explicitly modeled. To save computational time, an implicit boundary function is often used. Steele's potential has been used in studies of fluidsolid interface for a long time. In this work, the conceptual idea of Steele's potential was extended in order to simulate watersilicon and watersilica interfaces. A new wall potential model is developed by using the electronegativity-equalization method (EEM), a ReaxFF empirical force field and a non-reactive molecular dynamics package PumMa. Contact angle simulations were performed in order to validate the wall potential model. Contact angle simulations with the resulting tabulated wall potentials gave a siliconwater contact angle of 129, a quartzwater contact angle of 0, and a cristobalitewater contact angle of 40, which are in reasonable agreement with experimental values.

  18. Development of an operational tool to simulate pesticide transfer through vegetated strips: the 2D runoff part

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    dimensions. Materiel and method This tool uses Richards and Kinematic wave equations to describe respectively tables. Kinematic wave calculations are solved in two-dimensional form, using a finite volume method the most famous test to check if a code solving the kinematic wave is robust against hard changes of slopes

  19. Simulation as a Tool to Develop Guidelines of Envelope Design of a Typical Office Building in Egypt

    E-Print Network [OSTI]

    Samaan, M.M.; Ahmed, A.N.; Farag, O.M.A.; El-Sayed Khalil, M.

    2011-01-01T23:59:59.000Z

    This paper describes the use of building performance simulation software in order to develop guidelines for designing energy-efficient office building. In Egypt energy codes for all building types are being under development. On the other hand...

  20. HDL surface lipids mediate CETP binding as revealed by electron microscopy and molecular dynamics simulation

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

    Zhang, Meng; Charles, River; Tong, Huimin; Zhang, Lei; Patel, Mili; Wang, Francis; Rames, Matthew J.; Ren, Amy; Rye, Kerry-Anne; Qiu, Xiayang; et al

    2015-03-04T23:59:59.000Z

    Cholesteryl ester transfer protein (CETP) mediates the transfer of cholesterol esters (CE) from atheroprotective high-density lipoproteins (HDL) to atherogenic low-density lipoproteins (LDL). CETP inhibition has been regarded as a promising strategy for increasing HDL levels and subsequently reducing the risk of cardiovascular diseases (CVD). Although the crystal structure of CETP is known, little is known regarding how CETP binds to HDL. Here, we investigated how various HDL-like particles interact with CETP by electron microscopy and molecular dynamics simulations. Results showed that CETP binds to HDL via hydrophobic interactions rather than protein-protein interactions. The HDL surface lipid curvature generates a hydrophobicmoreenvironment, leading to CETP hydrophobic distal end interaction. This interaction is independent of other HDL components, such as apolipoproteins, cholesteryl esters and triglycerides. Thus, disrupting these hydrophobic interactions could be a new therapeutic strategy for attenuating the interaction of CETP with HDL.less

  1. Accelerating Dissipative Particle Dynamics Simulations on GPUs: Algorithms, Numerics and Applications

    E-Print Network [OSTI]

    Tang, Yu-Hang

    2013-01-01T23:59:59.000Z

    We present a scalable dissipative particle dynamics simulation code, fully implemented on the Graphics Processing Units (GPUs) using a hybrid CUDA/MPI programming model, which achieves 10-30 times speedup on a single GPU over 16 CPU cores and almost linear weak scaling across a thousand nodes. A unified framework is developed within which the efficient generation of the neighbor list and maintaining particle data locality are addressed. Our algorithm generates strictly ordered neighbor lists in parallel, while the construction is deterministic and makes no use of atomic operations or sorting. Such neighbor list leads to optimal data loading efficiency when combined with a two-level particle reordering scheme. A faster in situ generation scheme for Gaussian random numbers is proposed using precomputed binary signatures. We designed custom transcendental functions that are fast and accurate for evaluating the pairwise interaction. The correctness and accuracy of the code is verified through a set of test cases ...

  2. Molecular dynamics simulations of grain boundary thermal resistance in UO2

    SciTech Connect (OSTI)

    Tianyi Chen; Di Chen; Bulent H. Sencer; Lin Shao

    2014-09-01T23:59:59.000Z

    By means of molecular dynamics (MD) simulations, we have calculated Kaptiza resistance of UO2 with or without radiation damage. For coincident site lattice boundaries of different configurations, the boundary thermal resistance of unirradiated UO2 can be well described by a parameter-reduced formula by using boundary energies as variables. We extended the study to defect-loaded UO2 by introducing damage cascades in close vicinity to the boundaries. Following cascade annealing and defect migrations towards grain boundaries, the boundary energy increases and so does Kaptiza resistance. The correlations between these two still follow the same formula extracted from the unirradiated UO2. The finding will benefit multi-scale modeling of UO2 thermal properties under extreme radiation conditions by combining effects from boundary configurations and damage levels.

  3. Synchronized molecular-dynamics simulation for the thermal lubrication of a polymeric liquid between parallel plates

    E-Print Network [OSTI]

    Yasuda, Shugo

    2015-01-01T23:59:59.000Z

    The Synchronized Molecular-Dynamics simulation which was recently proposed by authors [Phys. Rev. X {\\bf 4}, 041011 (2014)] is applied to the analysis of polymer lubrication between parallel plates. The rheological properties, conformational change of polymer chains, and temperature rise due to the viscous heating are investigated with changing the values of thermal conductivity of the polymeric liquid. It is found that at a small applied shear stress on the plate, the temperature of polymeric liquid only slightly increases in inverse proportion to the thermal conductivity and the apparent viscosity of polymeric liquid is not much affected by changing the thermal conductivity. However, at a large shear stress, the transitional behaviors of the polymeric liquid occur due to the interplay of the shear deformation and viscous heating by changing the thermal conductivity. This transition is characterized by the Nahme-Griffith number $Na$ which is defined as the ratio of the viscous heating to the thermal conducti...

  4. Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions

    E-Print Network [OSTI]

    Priezjev, Nikolai V

    2012-01-01T23:59:59.000Z

    The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the slip length in oscillatory flows is plotted as a function of the local shear rate magnitude. For both types of flows, the friction coefficient at the liquid-solid interface correlates well with the structure of the first fluid layer near the solid wall.

  5. Molecular dynamics simulations of oscillatory Couette flows with slip boundary conditions

    E-Print Network [OSTI]

    Nikolai V. Priezjev

    2012-08-27T23:59:59.000Z

    The effect of interfacial slip on steady-state and time-periodic flows of monatomic liquids is investigated using non-equilibrium molecular dynamics simulations. The fluid phase is confined between atomically smooth rigid walls, and the fluid flows are induced by moving one of the walls. In steady shear flows, the slip length increases almost linearly with shear rate. We found that the velocity profiles in oscillatory flows are well described by the Stokes flow solution with the slip length that depends on the local shear rate. Interestingly, the rate dependence of the slip length obtained in steady shear flows is recovered when the slip length in oscillatory flows is plotted as a function of the local shear rate magnitude. For both types of flows, the friction coefficient at the liquid-solid interface correlates well with the structure of the first fluid layer near the solid wall.

  6. Solvent Electrostriction Driven Peptide Folding revealed by Quasi-Gaussian Entropy Theory and Molecular Dynamics Simulation

    SciTech Connect (OSTI)

    Noe, F [University of Heidelberg; Daidone, Isabella [University of Heidelberg; Smith, Jeremy C [ORNL; DiNola, Alfredo [University of Rome; Amadei, Andrea [University of Rome 'Tor Vergata', Rome, Italy

    2008-06-01T23:59:59.000Z

    A quantitative understanding of the complex relationship between microscopic structure and the thermodynamics driving peptide and protein folding is a major goal of biophysical chemistry. Here, we present a methodology comprising the use of an extended quasi-Gaussian entropy theory parametrized using molecular dynamics simulation that provides a complete description of the thermodynamics of peptide conformational states. The strategy is applied to analyze the conformational thermodynamics of MR121-GSGSW, a peptide well characterized in experimental studies. The results demonstrate that the extended state of the peptide possesses the lowest partial molar entropy. The origin of this entropy decrease is found to be in the increase of the density and orientational order of the hydration water molecules around the peptide, induced by the 'unfolding'. While such a reduction of the configurational entropy is usually associated with the hydrophobic effect, it is here found to be mainly due to the interaction of the solute charges with the solvent, that is, electrostriction.

  7. Solvent Electrostriction-Driven Peptide Folding Revealed by Quasi Gaussian Entropy Theory and Molecular Dynamics Simulation

    SciTech Connect (OSTI)

    Noe, F [University of Heidelberg; Daidone, Isabella [University of Heidelberg; Smith, Jeremy C [ORNL; DiNola, Alfredo [University of Rome; Amadei, Andrea [University of Rome 'Tor Vergata', Rome, Italy

    2008-08-01T23:59:59.000Z

    A quantitative understanding of the complex relationship between microscopic structure and the thermodynamics driving peptide and protein folding is a major goal of biophysical chemistry. Here, we present a methodology comprising the use of an extended quasi-Gaussian entropy theory parametrized using molecular dynamics simulation that provides a complete description of the thermodynamics of peptide conformational states. The strategy is applied to analyze the conformational thermodynamics of MR121-GSGSW, a peptide well characterized in experimental studies. The results demonstrate that the extended state of the peptide possesses the lowest partial molar entropy. The origin of this entropy decrease is found to be in the increase of the density and orientational order of the hydration water molecules around the peptide, induced by the 'unfolding'. While such a reduction of the configurational entropy is usually associated with the hydrophobic effect, it is here found to be mainly due to the interaction of the solute charges with the solvent, that is, electrostriction.

  8. Molecular Dynamics Simulation of Semiflexible Polyampholyte Brushes - The Effect of Charged Monomers Sequence

    E-Print Network [OSTI]

    M. Baratlo; H. Fazli

    2009-03-15T23:59:59.000Z

    Planar brushes formed by end-grafted semiflexible polyampholyte chains, each chain containing equal number of positively and negatively charged monomers is studied using molecular dynamics simulations. Keeping the length of the chains fixed, dependence of the average brush thickness and equilibrium statistics of the brush conformations on the grafting density and the salt concentration are obtained with various sequences of charged monomers. When similarly charged monomers of the chains are arranged in longer blocks, the average brush thickness is smaller and dependence of brush properties on the grafting density and the salt concentration is stronger. With such long blocks of similarly charged monomers, the anchored chains bond to each other in the vicinity of the grafting surface at low grafting densities and buckle toward the grafting surface at high grafting densities.

  9. Polymer segregation under confinement: Free energy calculations and segregation dynamics simulations

    E-Print Network [OSTI]

    James M. Polson; Logan G. Montgomery

    2014-10-09T23:59:59.000Z

    Monte Carlo simulations are used to study the behavior of two polymers under confinement in a cylindrical tube. Each polymer is modeled as a chain of hard spheres. We measure the free energy of the system, F, as a function of the distance between the centers of mass of the polymers, lambda, and examine the effects on the free energy functions of varying the channel diameter D and length L, as well as the polymer length N and bending rigidity, kappa. For infinitely long cylinders, F is a maximum at lambda=0, and decreases with lambda until the polymers are no longer in contact. For flexible chains, the polymers overlap along the cylinder for low lambda, while above some critical value of lambda they are longitudinally compressed and non-overlapping while still in contact. We find that the free energy barrier height, scales as Delta F/k_BT~ND^{-1.93+/-0.01}. In addition, the overlap free energy scales as F/k_BT=Nf(lambda/N;D), where f is a function parameterized by D. For channels of finite L, the free energy barrier height increases with increasing confinement aspect ratio L/D at fixed volume fraction phi, and it decreases with increasing phi at fixed L/D. Increasing the polymer bending rigidity kappa monotonically reduces the overlap free energy. For strongly confined systems, F varies linearly with lambda with a slope that scales as F'(lambda)~-k_BT D^{-beta} P^{-alpha}, where beta approx 2 and alpha approx 0.37 for N=200 chains. These exponent values deviate slightly from those predicted using a simple model, possibly due to insufficiently satisfying the conditions defining the Odijk regime. Finally, we use Monte Carlo dynamics simulations to examine polymer segregation dynamics for fully flexible chains and observe segregation rates that decrease with decreasing entropic force magnitude. The polymers are not conformationally relaxed at later times during segregation.

  10. Statechart Simulator for Modeling Architectural Dynamics1 Alexander Egyed Dave Wile

    E-Print Network [OSTI]

    Egyed, Alexander

    support for simulation. For instance, Darwin/LTSA [10,11] provides a simulator for executing labeled

  11. Dynamic Simulation of Shipping Package Subjected to Torque Load and Sequential Impacts

    SciTech Connect (OSTI)

    Wu, T

    2006-04-17T23:59:59.000Z

    A numerical technique has been developed to simulate the structural responses of radioactive material packaging components requiring closure-tightening torque to the scenarios of the hypothetical accident conditions (HAC) defined in the Code of Federal Regulations Title 10 part 71 (10CFR 71). A rigorous solution to this type of problem poses a considerable mathematical challenge. Conventional methods for evaluating the residue stresses due to the torque load are either inaccurate or not applicable to dynamic analyses. In addition, the HAC events occur sequentially and the cumulative damage to the package needs to be evaluated. Commonly, individual HAC events are analyzed separately and the cumulative damage is not addressed. As a result, strict compliance of the package with the requirements specified in 10CFR 71 is usually demonstrated by physical testing. The proposed technique utilizes the combination of kinematic constraints, rigid-body motions and structural deformations to overcome some of the difficulties encountered in modeling the effect of cumulative damage in numerical solutions. The analyses demonstrating use of this technique were performed to determine the cumulative damage of torque preload, a 30-foot drop, a 30-foot dynamic crush and a 40-inch free fall onto a mild steel pipe.

  12. Experiment and Simulation of Dynamic Voltage Regulation in Multiple Distributed Energy Resources Systems

    SciTech Connect (OSTI)

    Xu, Yan [ORNL; Li, Fangxing [ORNL; Kueck, John D [ORNL; Rizy, D Tom [ORNL

    2007-01-01T23:59:59.000Z

    Distributed energy (DE) resources are power sources located near load centers and equipped with power electronics converters to interface with the grid, therefore it is feasible for DE to provide reactive power (along with active power) locally for dynamic voltage regulation. In this paper, a synchronous condenser and a microturbine with an inverter interface are implemented in parallel in a distribution system to regulate the local voltage. Developed voltage control schemes for the inverter and the synchronous condenser are presented. Experimental results show that both the inverter and the synchronous condenser can regulate the local voltage instantaneously although the dynamic response of the inverter is much faster than the synchronous condenser. In a system with multiple DEs performing local voltage regulation, the interaction between the DEs is studied. The simulation results show the relationship between the voltages in the system and the reactive power required for the voltage regulation. Also, integrated voltage regulation (multiple DEs performing voltage regulation) can increase the voltage regulation capability of DEs and reduce the capital and operating costs.

  13. Properties of liquid clusters in large-scale molecular dynamics nucleation simulations

    SciTech Connect (OSTI)

    Anglil, Raymond; Diemand, Jrg [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland)] [Institute for Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Tanaka, Kyoko K.; Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)] [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)

    2014-02-21T23:59:59.000Z

    We have performed large-scale Lennard-Jones molecular dynamics simulations of homogeneous vapor-to-liquid nucleation, with 10{sup 9} atoms. This large number allows us to resolve extremely low nucleation rates, and also provides excellent statistics for cluster properties over a wide range of cluster sizes. The nucleation rates, cluster growth rates, and size distributions are presented in Diemand et al. [J. Chem. Phys. 139, 74309 (2013)], while this paper analyses the properties of the clusters. We explore the cluster temperatures, density profiles, potential energies, and shapes. A thorough understanding of the properties of the clusters is crucial to the formulation of nucleation models. Significant latent heat is retained by stable clusters, by as much as ?kT = 0.1? for clusters with size i = 100. We find that the clusters deviate remarkably from sphericalwith ellipsoidal axis ratios for critical cluster sizes typically within b/c = 0.7 0.05 and a/c = 0.5 0.05. We examine cluster spin angular momentum, and find that it plays a negligible role in the cluster dynamics. The interfaces of large, stable clusters are thinner than planar equilibrium interfaces by 10%?30%. At the critical cluster size, the cluster central densities are between 5% and 30% lower than the bulk liquid expectations. These lower densities imply larger-than-expected surface areas, which increase the energy cost to form a surface, which lowers nucleation rates.

  14. Many-body dissipative particle dynamics simulation of liquid/vapor and liquid/solid interactions

    SciTech Connect (OSTI)

    Arienti, Marco; Pan, Wenxiao; Li, Xiaoyi; Karniadakis, George E.

    2011-05-27T23:59:59.000Z

    The combination of short-range repulsive and long-range attractive forces in Many-body Dissipative Particle Dynamics (MDPD) is examined at a vapor/liquid and liquid/solid interface. Based on the radial distribution of the virial pressure in a drop at equilibrium, a systematic study is carried out to characterize the sensitivity of the surface tension coefficient with respect to the inter-particle interaction parameters. For the first time, this study highlights the approximately cubic dependence of the surface tension coefficient on the bulk density of the fluid. In capillary flow, MDPD solutions are shown to satisfy the condition on the wavelength of an axial disturbance leading to the pinch-off of a cylindrical liquid thread. Correctly, no pinch-off occurs below the cutoff wavelength. MDPD is augmented by a set of bell-shaped weight functions to model interaction with a solid wall. There, hydrophilic and hydrophobic behaviors, including the occurrence of slip in the latter, are reproduced using a modification in the weight function that avoids particle clustering. Finally, the dynamics of droplets entering an inverted Y-shaped fracture junction is correctly captured in simulations parameterized by the Bond number, proving the flexibility of MDPD in modeling interface-dominated flows.

  15. Molecular Dynamics Simulation of Cascade-Induced Ballistic Helium Resolutioning from Bubbles in Iron

    SciTech Connect (OSTI)

    Stoller, Roger E [ORNL] [ORNL

    2013-01-01T23:59:59.000Z

    Molecular dynamics simulations have been used to assess the ability of atomic displacement cascades to eject helium from small bubbles in iron. This study of the ballistic resolutioning mechanism employed a recently-developed Fe-He interatomic potential in concert with an iron potential developed by Ackland and co-workers. The primary variables examined were: irradiation temperature (100 and 600K), cascade energy (5 and 20 keV), bubble radius (0.5 and 1.0 nm), and He-to-vacancy ratio in the bubble (0.25, 0.5 and 1.0). Systematic trends were observed for each of these variables. For example, ballistic resolutioning leads to a greater number of helium atoms being displaced from larger bubbles and from bubbles that have a higher He/vacancy ratio (bubble pressure). He resolutioning was reduced at 600K relative to 100K, and for 20 keV cascades relative to 5 keV cascades. Overall, the results indicate a modest level of He removal by ballistic resolutioning. The results can be used to provide guidance in selection of a resolution parameter that can be employed in cluster dynamics models to predict the bubble size distribution that evolves under irradiation.

  16. The use of dynamic adaptive chemistry in combustion simulation of gasoline surrogate fuels

    SciTech Connect (OSTI)

    Liang, Long; Raman, Sumathy; Farrell, John T. [Corporate Strategic Research Laboratories, ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, NJ 08801 (United States); Stevens, John G. [Corporate Strategic Research Laboratories, ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, NJ 08801 (United States); Department of Mathematical Sciences, Montclair State University, Montclair, NJ 07043 (United States)

    2009-07-15T23:59:59.000Z

    A computationally efficient dynamic adaptive chemistry (DAC) scheme is described that permits on-the-fly mechanism reduction during reactive flow calculations. The scheme reduces a globally valid full mechanism to a locally, instantaneously applicable smaller mechanism. Previously we demonstrated its applicability to homogeneous charge compression ignition (HCCI) problems with n-heptane [L. Liang, J.G. Stevens, J.T. Farrell, Proc. Combust. Inst. 32 (2009) 527-534]. In this work we demonstrate the broader utility of the DAC scheme through the simulation of HCCI and shock tube ignition delay times (IDT) for three gasoline surrogates, including two- and three-component blends of primary reference fuels (PRF) and toluene reference fuels (TRF). Both a detailed 1099-species mechanism and a skeletal 150-species mechanism are investigated as the full mechanism to explore the impact of fuel complexity on the DAC scheme. For all conditions studied, pressure and key species profiles calculated using the DAC scheme are in excellent agreement with the results obtained using the full mechanisms. For the HCCI calculations using the 1099- and 150-species mechanisms, the DAC scheme achieves 70- and 15-fold CPU time reductions, respectively. For the IDT problems, corresponding speed-up factors of 10 and two are obtained. Practical guidance is provided for choosing the search-initiating species set, selecting the threshold, and implementing the DAC scheme in a computational fluid dynamics (CFD) framework. (author)

  17. Integration Schemes for Dissipative Particle Dynamics Simulations: From Softly Interacting Systems Towards Hybrid Models

    E-Print Network [OSTI]

    Ilpo Vattulainen; Mikko Karttunen; Gerhard Besold; J. M. Polson

    2002-11-15T23:59:59.000Z

    We examine the performance of various commonly used integration schemes in dissipative particle dynamics simulations. We consider this issue using three different model systems, which characterize a variety of different conditions often studied in simulations. Specifically we clarify the performance of integration schemes in hybrid models, which combine microscopic and meso-scale descriptions of different particles using both soft and hard interactions. We find that in all three model systems many commonly used integrators may give rise to surprisingly pronounced artifacts in physical observables such as the radial distribution function, the compressibility, and the tracer diffusion coefficient. The artifacts are found to be strongest in systems, where interparticle interactions are soft and predominated by random and dissipative forces, while in systems governed by conservative interactions the artifacts are weaker. Our results suggest that the quality of any integration scheme employed is crucial in all cases where the role of random and dissipative forces is important, including hybrid models where the solvent is described in terms of soft potentials.

  18. Compositional Control of Surface Oxides on Metal Alloys using Photons: Dynamic Simulations and Experiments

    SciTech Connect (OSTI)

    Chang, C.; Sankaranarayanan, S; Ruzmetov, D; Engelhard, M; Kaxiras, E; Ramanathan, S

    2010-01-01T23:59:59.000Z

    We report on the ability to modify the structure and composition of ultrathin oxides grown on Ni and Ni-Al alloy surfaces at room temperature utilizing photon illumination. We find that the nickel-oxide formation is enhanced in the case of oxidation under photo-excitation. The enhanced oxidation kinetics of nickel in 5% Ni-Al alloy is corroborated by experimental and simulation studies of natural and photon-assisted oxide growth on pure Ni(100) surfaces. In case of pure Ni substrates, combined x-ray photoelectron spectroscopy analysis, and atomic force microscope current mapping support the deterministic role of the structure of nickel passive-oxide films on their nanoscale corrosion resistance. Atomistic simulations involving dynamic charge transfer predict that the applied electric field overcomes the activation-energy barrier for ionic migration, leading to enhanced oxygen incorporation into the oxide, enabling us to tune the mixed-oxide composition at atomic length scales. Atomic scale control of ultrathin oxide structure and morphology in the case of pure substrates as well as compositional tuning of complex oxide in the case of alloys leads to excellent passivity as verified from potentiodynamic polarization experiments.

  19. BEAM DYNAMICS SIMULATIONS OF SARAF ACCELERATOR INCLUDING ERROR PROPAGATION AND IMPLICATIONS FOR THE EURISOL DRIVER

    E-Print Network [OSTI]

    J. Rodnizki, D. Berkovits, K. Lavie, I. Mardor, A. Shor and Y. Yanay (Soreq NRC, Yavne), K. Dunkel, C. Piel (ACCEL, Bergisch Gladbach), A. Facco (INFN/LNL, Legnaro, Padova), V. Zviagintsev (TRIUMF, Vancouver)

    AbstractBeam dynamics simulations of SARAF (Soreq Applied Research Accelerator Facility) superconducting RF linear accelerator have been performed in order to establish the accelerator design. The multi-particle simulation includes 3D realistic electromagnetic field distributions, space charge forces and fabrication, misalignment and operation errors. A 4 mA proton or deuteron beam is accelerated up to 40 MeV with a moderated rms emittance growth and a high real-estate gradient of 2 MeV/m. An envelope of 40,000 macro-particles is kept under a radius of 1.1 cm, well below the beam pipe bore radius. The accelerator design of SARAF is proposed as an injector for the EURISOL driver accelerator. The Accel 176 MHZ ?0=0.09 and ?0=0.15 HWR lattice was extended to 90 MeV based on the LNL 352 MHZ ?0=0.31 HWR. The matching between both lattices ensures smooth transition and the possibility to extend the accelerator to the required EURISOL ion energy.

  20. Molecular Dynamics Simulations of Uranyl and Uranyl Carbonate Adsorption at Alumino-silicate Surfaces

    SciTech Connect (OSTI)

    Kerisit, Sebastien N.; Liu, Chongxuan

    2014-03-03T23:59:59.000Z

    Adsorption at mineral surfaces is a critical factor controlling the mobility of uranium(VI) in aqueous environments. Therefore, molecular dynamics (MD) simulations were performed to investigate uranyl(VI) adsorption onto two neutral alumino-silicate surfaces, namely the orthoclase (001) surface and the octahedral aluminum sheet of the kaolinite (001) surface. Although uranyl preferentially adsorbed as a bi-dentate innersphere complex on both surfaces, the free energy of adsorption at the orthoclase surface (-15 kcal mol-1) was significantly more favorable than that at the kaolinite surface (-3 kcal mol-1), which was attributed to differences in surface functional groups and to the ability of the orthoclase surface to dissolve a surface potassium ion upon uranyl adsorption. The structures of the adsorbed complexes compared favorably with X-ray absorption spectroscopy results. Simulations of the adsorption of uranyl complexes with up to three carbonate ligands revealed that uranyl complexes coordinated to up to 2 carbonate ions are stable on the orthoclase surface whereas uranyl carbonate surface complexes are unfavored at the kaolinite surface. Combining the MD-derived equilibrium adsorption constants for orthoclase with aqueous equilibrium constants for uranyl carbonate species indicates the presence of adsorbed uranium complexes with one or two carbonates in alkaline conditions, in support of current uranium(VI) surface complexation models.

  1. Molecular dynamics simulations of intergranular fracture in UO2 with nine empirical interatomic potentials

    SciTech Connect (OSTI)

    Yongfeng Zhang; Paul C Millett; Michael R Tonks; Xian-Ming Bai; S Bulent Biner

    2014-09-01T23:59:59.000Z

    The intergranular fracture behavior of UO2 was studied using molecular dynamics simulations with a bicrystal model. The anisotropic fracture behavior due to the different grain boundary characters was investigated with the View the MathML source symmetrical tilt S5 and the View the MathML source symmetrical tilt S3 ({1 1 1} twin) grain boundaries. Nine interatomic potentials, seven rigid-ion plus two coreshell ones, were utilized to elucidate possible potential dependence. Initiating from a notch, crack propagation along grain boundaries was observed for most potentials. The S3 boundary was found to be more prone to fracture than the S5 one, indicated by a lower energy release rate associated with the former. However, some potential dependence was identified on the existence of transient plastic deformation at crack tips, and the results were discussed regarding the relevant material properties including the excess energies of metastable phases and the critical energy release rate for intergranular fracture. In general, local plasticity at crack tips was observed in fracture simulations with potentials that predict low excess energies for metastable phases and high critical energy release rates for intergranular fracture.

  2. Ratcheted molecular-dynamics simulations identify efficiently the transition state of protein folding

    E-Print Network [OSTI]

    Guido Tiana; Carlo Camilloni

    2012-07-05T23:59:59.000Z

    The atomistic characterization of the transition state is a fundamental step to improve the understanding of the folding mechanism and the function of proteins. From a computational point of view, the identification of the conformations that build out the transition state is particularly cumbersome, mainly because of the large computational cost of generating a statistically-sound set of folding trajectories. Here we show that a biasing algorithm, based on the physics of the ratchet-and-pawl, can be used to identify efficiently the transition state. The basic idea is that the algorithmic ratchet exerts a force on the protein when it is climbing the free-energy barrier, while it is inactive when it is descending. The transition state can be identified as the point of the trajectory where the ratchet changes regime. Besides discussing this strategy in general terms, we test it within a protein model whose transition state can be studied independently by plain molecular dynamics simulations. Finally, we show its power in explicit-solvent simulations, obtaining and characterizing a set of transition--state conformations for ACBP and CI2.

  3. Dynamic simulation of 10 kW Brayton cryocooler for HTS cable

    SciTech Connect (OSTI)

    Chang, Ho-Myung; Park, Chan Woo [Hong Ik University, Department of Mechanical Engineering, Seoul, 121-791 (Korea, Republic of); Yang, Hyung Suk; Hwang, Si Dole [KEPCO Research Institute, Daejeon, 305-760 (Korea, Republic of)

    2014-01-29T23:59:59.000Z

    Dynamic simulation of a Brayton cryocooler is presented as a partial effort of a Korean governmental project to develop 1?3 km HTS cable systems at transmission level in Jeju Island. Thermodynamic design of a 10 kW Brayton cryocooler was completed, and a prototype construction is underway with a basis of steady-state operation. This study is the next step to investigate the transient behavior of cryocooler for two purposes. The first is to simulate and design the cool-down process after scheduled or unscheduled stoppage. The second is to predict the transient behavior following the variation of external conditions such as cryogenic load or outdoor temperature. The detailed specifications of key components, including plate-fin heat exchangers and cryogenic turbo-expanders are incorporated into a commercial software (Aspen HYSYS) to estimate the temporal change of temperature and flow rate over the cryocooler. An initial cool-down scenario and some examples on daily variation of cryocooler are presented and discussed, aiming at stable control schemes of a long cable system.

  4. Real-space grids and the Octopus code as tools for the development of new simulation approaches for electronic systems

    E-Print Network [OSTI]

    Andrade, Xavier; De Giovannini, Umberto; Larsen, Ask Hjorth; Oliveira, Micael J T; Alberdi-Rodriguez, Joseba; Varas, Alejandro; Theophilou, Iris; Helbig, Nicole; Verstraete, Matthieu; Stella, Lorenzo; Nogueira, Fernando; Aspuru-Guzik, Aln; Castro, Alberto; Marques, Miguel A L; Rubio, ngel

    2015-01-01T23:59:59.000Z

    Real-space grids are a powerful alternative for the simulation of electronic systems. One of the main advantages of the approach is the flexibility and simplicity of working directly in real space where the different fields are discretized on a grid, combined with competitive numerical performance and great potential for parallelization. These properties constitute a great advantage at the time of implementing and testing new physical models. Based on our experience with the Octopus code, in this article we discuss how the real-space approach has allowed for the recent development of new ideas for the simulation of electronic systems. Among these applications are approaches to calculate response properties, modeling of photoemission, optimal control of quantum systems, simulation of plasmonic systems, and the exact solution of the Schr\\"odinger equation for low-dimensionality systems.

  5. Dynamical Downscaling of GCM Simulations: Toward the Improvement of Forecast Bias over California

    SciTech Connect (OSTI)

    Chin, H S

    2008-09-24T23:59:59.000Z

    The effects of climate change will mostly be felt on local to regional scales. However, global climate models (GCMs) are unable to produce reliable climate information on the scale needed to assess regional climate-change impacts and variability as a result of coarse grid resolution and inadequate model physics though their capability is improving. Therefore, dynamical and statistical downscaling (SD) methods have become popular methods for filling the gap between global and local-to-regional climate applications. Recent inter-comparison studies of these downscaling techniques show that both downscaling methods have similar skill in simulating the mean and variability of present climate conditions while they show significant differences for future climate conditions (Leung et al., 2003). One difficulty with the SD method is that it relies on predictor-predict and relationships, which may not hold in future climate conditions. In addition, it is now commonly accepted that the dynamical downscaling with the regional climate model (RCM) is more skillful at the resolving orographic climate effect than the driving coarser-grid GCM simulations. To assess the possible societal impacts of climate changes, many RCMs have been developed and used to provide a better projection of future regional-scale climates for guiding policies in economy, ecosystem, water supply, agriculture, human health, and air quality (Giorgi et al., 1994; Leung and Ghan, 1999; Leung et al., 2003; Liang et al., 2004; Kim, 2004; Duffy et al., 2006). Although many regional climate features, such as seasonal mean and extreme precipitation have been successfully captured in these RCMs, obvious biases of simulated precipitation remain, particularly the winter wet bias commonly seen in mountain regions of the Western United States. The importance of regional climate research over California is not only because California has the largest population in the nation, but California has one of the most sophisticated water collection and distribution systems in the world. Therefore, adapting California's water management system to climate change presents significant challenges. Besides, the strong scale interaction between atmospheric circulation and topography in this region provides a challenging testbed for RCMs. Thus, the success of California winter precipitation forecast over mountains would greatly help develop a reliable water management system to adapt to climate change.

  6. Incremental Integration Tools for Chemical Engineering: An Industrial Application of Triple Graph

    E-Print Network [OSTI]

    Westfechtel, Bernhard

    and the components of the chemical plant, simulation models for steady-state and dynamic simulations, etc. Design representations of a chemical plant have to be kept consistent with each other. Incremental integration tools). In chemical engineering design, a chemical plant is described from different per- spectives by a set

  7. daVinci Code: A Multi-Model Simulation and Analysis Tool for Multi-Body Systems

    E-Print Network [OSTI]

    Trinkle, Jeff

    , analysis, and virtual design of multibody systems with intermittent unilateral con- tacts with dry friction soft- ware for simulating multibody systems with unilateral con- tacts and dry friction (DADs, Adams of simulat- ing planar systems of bodies experiencing unilateral contacts with friction. Since different

  8. Development and simulation of a cylindrical cusped-field thruster and a diagnostics tool for plasma-materials interactions

    E-Print Network [OSTI]

    Pang, Anthony

    2013-01-01T23:59:59.000Z

    A low power, Hall-effect type plasma thruster known as the MIT-Cylindrical Cusped- Field Thruster (MIT-CCFT) has been developed and simulated using a fully-kinetic plasma model, the Plasma Thruster particle-in-cell (PTpic) ...

  9. Hypermolecular dynamics simulations of monovacancy X.M. Duan *, D.Y. Sun, X.G. Gong

    E-Print Network [OSTI]

    Gong, Xingao

    Hypermolecular dynamics simulations of monovacancy diusion X.M. Duan *, D.Y. Sun, X.G. Gong@theory.issp.ac.cn (X.M. Duan), dysun@theory.issp.ac.cn (D.Y. Sun), gong@theory.issp.ac.cn (X.G. Gong). 0927 of moving at- oms, which prohibits application to large systems. Very recently, Gong and Wilkins [17

  10. THE JOURNAL OF CHEMICAL PHYSICS 138, 244310 (2013) Molecular dynamics simulations for CO2 spectra. IV. Collisional line-mixing

    E-Print Network [OSTI]

    Boyer, Edmond

    2013-01-01T23:59:59.000Z

    atmosphere of Venus (about 96.5% of CO2) where the pressure is high (up to 90 bar). Similarly, narrow involving CO2 with a few for the pure gas in the infrared at high pressure1217 and Raman Q branches.4THE JOURNAL OF CHEMICAL PHYSICS 138, 244310 (2013) Molecular dynamics simulations for CO2 spectra

  11. A molecular dynamics simulation of the melting points and glass transition temperatures of myo-and neo-inositol

    E-Print Network [OSTI]

    de Gispert, Adri

    A molecular dynamics simulation of the melting points and glass transition temperatures of myo transition temperature are calculated for myo- and neo-inositol, using the condensed-phase optimized temperatures for myo- and neo-inositol also compare very well to the experimentally obtained data. The glass

  12. Molecular Dynamics Simulation of Heat Transfer Issues of Nanotubes. > Yasuhiro Igarashi, Yuki Taniguchi, Yasushi Shibuta and Shigeo Maruyama

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Molecular Dynamics Simulation of Heat Transfer Issues of Nanotubes. > Yasuhiro Igarashi, Yuki 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Heat transfer between single-walled carbon nanotubes, which was 0.105 m. In other words, when the length of SWNT is 0.105 m, the radial heat transfer

  13. Structural relaxation of polydisperse hard spheres: comparison of the mode-coupling theory to a Langevin dynamics simulation

    E-Print Network [OSTI]

    F. Weysser; A. M. Puertas; M. Fuchs; Th. Voigtmann

    2010-10-15T23:59:59.000Z

    We analyze the slow, glassy structural relaxation as measured through collective and tagged-particle density correlation functions obtained from Brownian dynamics simulations for a polydisperse system of quasi-hard spheres in the framework of the mode-coupling theory of the glass transition (MCT). Asymptotic analyses show good agreement for the collective dynamics when polydispersity effects are taken into account in a multi-component calculation, but qualitative disagreement at small $q$ when the system is treated as effectively monodisperse. The origin of the different small-$q$ behaviour is attributed to the interplay between interdiffusion processes and structural relaxation. Numerical solutions of the MCT equations are obtained taking properly binned partial static structure factors from the simulations as input. Accounting for a shift in the critical density, the collective density correlation functions are well described by the theory at all densities investigated in the simulations, with quantitative agreement best around the maxima of the static structure factor, and worst around its minima. A parameter-free comparison of the tagged-particle dynamics however reveals large quantiative errors for small wave numbers that are connected to the well-known decoupling of self-diffusion from structural relaxation and to dynamical heterogeneities. While deviations from MCT behaviour are clearly seen in the tagged-particle quantities for densities close to and on the liquid side of the MCT glass transition, no such deviations are seen in the collective dynamics.

  14. Computational Tools to Accelerate Commercial Development

    SciTech Connect (OSTI)

    Miller, David C.

    2013-01-01T23:59:59.000Z

    The goals of the work reported are: to develop new computational tools and models to enable industry to more rapidly develop and deploy new advanced energy technologies; to demonstrate the capabilities of the CCSI Toolset on non-proprietary case studies; and to deploy the CCSI Toolset to industry. Challenges of simulating carbon capture (and other) processes include: dealing with multiple scales (particle, device, and whole process scales); integration across scales; verification, validation, and uncertainty; and decision support. The tools cover: risk analysis and decision making; validated, high-fidelity CFD; high-resolution filtered sub-models; process design and optimization tools; advanced process control and dynamics; process models; basic data sub-models; and cross-cutting integration tools.

  15. Structure and Dynamics of the Instantaneous Water/Vapor Interface Revisited by Path-Integral and Ab-Initio Molecular Dynamics Simulations

    E-Print Network [OSTI]

    Kessler, Jan; Spura, Thomas; Karhan, Kristof; Partovi-Azar, Pouya; Hassanali, Ali A; Khne, Thomas D

    2015-01-01T23:59:59.000Z

    The structure and dynamics of the water/vapor interface is revisited by means of path-integral and second-generation Car-Parrinello ab-initio molecular dynamics simulations in conjunction with an instantaneous surface definition [A. P. Willard and D. Chandler, J. Phys. Chem. B 114, 1954 (2010)]. In agreement with previous studies, we find that one of the OH bonds of the water molecules in the topmost layer is pointing out of the water into the vapor phase, while the orientation of the underlying layer is reversed. Therebetween, an additional water layer is detected, where the molecules are aligned parallel to the instantaneous water surface.

  16. Calculation of unsteady turbulent flow around obstacles using the large eddy simulation turbulence model

    E-Print Network [OSTI]

    Helton, Donald McLean

    2002-01-01T23:59:59.000Z

    The premise of the work presented here is to use a common analytical tool, Computational Fluid Dynamics (CFD), along with a prevalent turbulence model, Large Eddy Simulation (LES), to study the flow past rectangular cylinders. In an attempt to use...

  17. Extending the Use of Archived ITS Data As a Potential Management Tool to Evaluate Traveler Information on Dynamic Message Signs

    E-Print Network [OSTI]

    Bertini, Robert L.

    Information on Dynamic Message Signs Priya Chavan Department of Computer Science Portland State University Dynamic Message Signs (DMS) on freeways are often used to provide a variety of information to motorists such as Amber Alerts. The display of accurate travel time messages is currently of high importance

  18. The Dynamics of Sinking Satellites Around Disk Galaxies: A Poor Man's Alternative to High-Resolution Numerical Simulations

    E-Print Network [OSTI]

    J. E. Taylor; Arif Babul

    2000-12-14T23:59:59.000Z

    We have developed a simple yet surprisingly accurate analytic scheme for tracking the dynamical evolution of substructure within larger dark halos. The scheme incorporates the effects of dynamical friction, tidal mass loss and tidal heating via physically motivated approximations. Using our scheme, we can predict the orbital evolution and mass-loss history of individual subhalos in detail. We are also able to determine the impact and importance of the different physical processes on the dynamical evolution of the subhalos. To test and calibrate this model, we compare it with a set of recent high-resolution numerical simulations of mergers between galaxies and small companions. We find that we can reproduce the orbits and mass-loss rates seen in all of these simulations with considerable accuracy, using a single set of values for the three free parameters in our model. Computationally, our scheme is more than 1000 times faster than the simplest of the high-resolution numerical simulations. This means that we can carry out detailed and statistically meaningful investigations into the characteristics of the subhalo population in different cosmologies, the stripping and disruption of the subhalos, and the interactions of the subhalos with other dynamical structures such as a thin disk. This last point is of particular interest given the ubiquity of minor mergers in hierarchical models. In this regard, our method's simplicity and speed makes it particularly attractive for incorporation into semi-analytic models of galaxy formation.

  19. Final technical report [ACCELERATED MOLECULAR DYNAMICS SIMULATIONS OF REACTIVE HYDROCARBON SYSTEMS

    SciTech Connect (OSTI)

    Stuart, Steven J.

    2014-02-25T23:59:59.000Z

    The research activities in this project consisted of four different sub-projects. Three different accelerated dynamics techniques (parallel replica dynamics, hyperdynamics, and temperature-accelerated dynamics) were applied to the modeling of pyrolysis of hydrocarbons. In addition, parallel replica dynamics was applied to modeling of polymerization.

  20. Molecular-dynamics simulation of clustering processes in sea-ice floes

    E-Print Network [OSTI]

    Herman, Agnieszka

    2011-01-01T23:59:59.000Z

    In seasonally ice-covered seas and along the margins of perennial ice pack, i.e. in regions with medium ice concentrations, the ice cover typically consists of separate floes interacting with each other by inelastic collisions. In this paper, hitherto unexplored analogies between this type of ice cover and two-dimensional granular gases are used to formulate a model of ice dynamics at the floe level. The model consists of: (i) momentum equations for floe motion between collisions, formulated in the form of a Stokes-flow problem, with floe-size dependent time constant and equilibrium velocity, and (ii) hard-disk collision model. The numerical algorithm developed is suitable for simulating particle-laden flow of $N$ disk-shaped floes with arbitrary size distribution. The model is applied to study clustering phenomena in sea ice with power-law floe-size distribution. In particular, the influence of the average ice concentration $\\bar{A}$ on the formation and characteristics of clusters is analyzed in detail. The...

  1. Synchronized molecular-dynamics simulation for the thermal lubrication of a polymeric liquid between parallel plates

    E-Print Network [OSTI]

    Shugo Yasuda; Ryoichi Yamamoto

    2015-03-25T23:59:59.000Z

    The Synchronized Molecular-Dynamics simulation which was recently proposed by authors [Phys. Rev. X {\\bf 4}, 041011 (2014)] is applied to the analysis of polymer lubrication between parallel plates. The rheological properties, conformational change of polymer chains, and temperature rise due to the viscous heating are investigated with changing the values of thermal conductivity of the polymeric liquid. It is found that at a small applied shear stress on the plate, the temperature of polymeric liquid only slightly increases in inverse proportion to the thermal conductivity and the apparent viscosity of polymeric liquid is not much affected by changing the thermal conductivity. However, at a large shear stress, the transitional behaviors of the polymeric liquid occur due to the interplay of the shear deformation and viscous heating by changing the thermal conductivity. This transition is characterized by the Nahme-Griffith number $Na$ which is defined as the ratio of the viscous heating to the thermal conduction at a characteristic temperature. When the Nahme-Griffith number exceeds the unity, the temperature of polymeric liquid increases rapidly and the apparent viscosity also exponentially decreases as the thermal conductivity decreases. The conformation of polymer chains is stretched and aligned by the shear flow for $Na1$.

  2. Thermal Degradation of Adsorbed Bottle-Brush Macromolecules: Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Andrey Milchev; Jaroslaw Paturej; Vakhtang G. Rostiashvili; Thomas A. Vilgis

    2011-03-03T23:59:59.000Z

    The scission kinetics of bottle-brush molecules in solution and on an adhesive substrate is modeled by means of Molecular Dynamics simulation with Langevin thermostat. Our macromolecules comprise a long flexible polymer backbone with $L$ segments, consisting of breakable bonds, along with two side chains of length $N$, tethered to each segment of the backbone. In agreement with recent experiments and theoretical predictions, we find that bond cleavage is significantly enhanced on a strongly attractive substrate even though the chemical nature of the bonds remains thereby unchanged. We find that the mean bond life time $$ decreases upon adsorption by more than an order of magnitude even for brush molecules with comparatively short side chains $N=1 \\div 4$. The distribution of scission probability along the bonds of the backbone is found to be rather sensitive regarding the interplay between length and grafting density of side chains. The life time $$ declines with growing contour length $L$ as $\\propto L^{-0.17}$, and with side chain length as $\\propto N^{-0.53}$. The probability distribution of fragment lengths at different times agrees well with experimental observations. The variation of the mean length $L(t)$ of the fragments with elapsed time confirms the notion of the thermal degradation process as a first order reaction.

  3. Use of a dynamic simulation model to understand nitrogen cycling in the middle Rio Grande, NM.

    SciTech Connect (OSTI)

    Meixner, Tom (University of Arizona, Tucson, AZ); Tidwell, Vincent Carroll; Oelsner, Gretchen (University of Arizona, Tucson, AZ); Brooks, Paul (University of Arizona, Tucson, AZ); Roach, Jesse D.

    2008-08-01T23:59:59.000Z

    Water quality often limits the potential uses of scarce water resources in semiarid and arid regions. To best manage water quality one must understand the sources and sinks of both solutes and water to the river system. Nutrient concentration patterns can identify source and sink locations, but cannot always determine biotic processes that affect nutrient concentrations. Modeling tools can provide insight into these large-scale processes. To address questions about large-scale nitrogen removal in the Middle Rio Grande, NM, we created a system dynamics nitrate model using an existing integrated surface water--groundwater model of the region to evaluate our conceptual models of uptake and denitrification as potential nitrate removal mechanisms. We modeled denitrification in groundwater as a first-order process dependent only on concentration and used a 5% denitrification rate. Uptake was assumed to be proportional to transpiration and was modeled as a percentage of the evapotranspiration calculated within the model multiplied by the nitrate concentration in the water being transpired. We modeled riparian uptake as 90% and agricultural uptake as 50% of the respective evapotranspiration rates. Using these removal rates, our model results suggest that riparian uptake, agricultural uptake and denitrification in groundwater are all needed to produce the observed nitrate concentrations in the groundwater, conveyance channels, and river as well as the seasonal concentration patterns. The model results indicate that a total of 497 metric tons of nitrate-N are removed from the Middle Rio Grande annually. Where river nitrate concentrations are low and there are no large nitrate sources, nitrate behaves nearly conservatively and riparian and agricultural uptake are the most important removal mechanisms. Downstream of a large wastewater nitrate source, denitrification and agricultural uptake were responsible for approximately 90% of the nitrogen removal.

  4. Molecular dynamics simulation study of the high frequency sound waves in the fragile glass former ortho-terphenyl

    E-Print Network [OSTI]

    S. Mossa; G. Monaco; G. Ruocco; M. Sampoli; F. Sette

    2001-04-07T23:59:59.000Z

    Using a realistic flexible molecule model of the fragile glass former orthoterphenyl, we calculate via molecular dynamics simulation the collective dynamic structure factor, recently measured in this system by Inelastic X-ray Scattering. The comparison of the simulated and measured dynamic structure factor, and the study of its properties in an extended momentum, frequency and temperature range allows: i) to conclude that the utilized molecular model gives rise to a dynamic structure factor in agreement with the experimental data, for those thermodynamic states and momentum values where the latter are available; ii) to confirm the existence of a slope discontinuity on the T-dependence of the sound velocity that, at finite Q, takes place at a temperature T_x higher than the calorimetric glass transition temperature T_g; iii) to find that the values of T_x is Q-dependent and that its vanishing Q limit is consistent with T_g. The latter finding is interpreted within the framework of the current description of the dynamics of supercooled liquids in terms of exploration of the potential energy landscape.

  5. Development of a Modelling and Simulation Method Comparison and Selection Framework for Health Services Management

    E-Print Network [OSTI]

    Jun, Gyuchan T; Morris, Zoe; Eldabi, Tillal; Harper, Paul; Naseer, Aisha; Patel, Brijesh; Clarkson, John P

    2011-05-19T23:59:59.000Z

    Simulation, Mathematical Programming/Optimisation Methods, Markov Models, Queuing Theory, Structural Equation Modelling, System Dynamics, Process Mapping, Spatial Mapping, Monte Carlo Simulation, Cognitive Mapping, Soft Systems Methodology 2. Simulation... analysis Table 2 Twenty eight methods identified for the selection tool Categories No. Methods Problem Structuring Methods 1 Drama Theory & Confrontation Analysis 2 Robustness Analysis 3 Soft Systems Methodology 4 Strategic Choice Approach 5 Strategic...

  6. A comparison of neutron scattering studies and computer simulations of polymer melts

    E-Print Network [OSTI]

    Utah, University of

    A comparison of neutron scattering studies and computer simulations of polymer melts G.D. Smith a; in nal form 22 May 2000 Abstract Neutron scattering and computer simulations are powerful tools in particular. When neutron scattering studies and quan- titative atomistic molecular dynamics simulations

  7. A comparative study of Lotka-Volterra and system dynamics models for simulation of technology industry dynamics

    E-Print Network [OSTI]

    nver, Hakk? zgr

    2008-01-01T23:59:59.000Z

    Scholars have developed a range of qualitative and quantitative models for generalizing the dynamics of technological innovation and identifying patterns of competition between rivals. This thesis compares two predominant ...

  8. Does fluoride disrupt hydrogen bond network in cationic lipid bilayer? Time-dependent fluorescence shift of Laurdan and molecular dynamics simulations

    SciTech Connect (OSTI)

    Pokorna, Sarka; Jurkiewicz, Piotr; Hof, Martin, E-mail: martin.hof@jh-inst.cas.cz [J. Heyrovsk Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8 (Czech Republic); Vazdar, Mario [Division of Organic Chemistry and Biochemistry, Rudjer Bokovi? Institute, P.O.B. 180, HR-10002 Zagreb (Croatia); Cwiklik, Lukasz [J. Heyrovsk Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223 Prague 8 (Czech Republic); Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nm. 2, 16610 Prague 6 (Czech Republic); Jungwirth, Pavel [Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nm. 2, 16610 Prague 6 (Czech Republic); Department of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)

    2014-12-14T23:59:59.000Z

    Time-dependent fluorescence shift (TDFS) of Laurdan embedded in phospholipid bilayers reports on hydration and mobility of the phospholipid acylgroups. Exchange of H{sub 2}O with D{sub 2}O prolongs the lifetime of lipid-water and lipid-water-lipid interactions, which is reflected in a significantly slower TDFS kinetics. Combining TDFS measurements in H{sub 2}O and D{sub 2}O hydrated bilayers with atomistic molecular dynamics (MD) simulations provides a unique tool for characterization of the hydrogen bonding at the acylgroup level of lipid bilayers. In this work, we use this approach to study the influence of fluoride anions on the properties of cationic bilayers composed of trimethylammonium-propane (DOTAP). The results obtained for DOTAP are confronted with those for neutral phosphatidylcholine (DOPC) bilayers. Both in DOTAP and DOPC H{sub 2}O/D{sub 2}O exchange prolongs hydrogen-bonding lifetime and does not disturb bilayer structure. These results are confirmed by MD simulations. TDFS experiments show, however, that for DOTAP this effect is cancelled in the presence of fluoride ions. We interpret these results as evidence that strongly hydrated fluoride is able to steal water molecules that bridge lipid carbonyls. Consequently, when attracted to DOTAP bilayer, fluoride disrupts the local hydrogen-bonding network, and the differences in TDFS kinetics between H{sub 2}O and D{sub 2}O hydrated bilayers are no longer observed. A distinct behavior of fluoride is also evidenced by MD simulations, which show different lipid-ion binding for Cl{sup ?} and F{sup ?}.

  9. A Robust Four-Fluid Transient Flow Simulator as an Analysis and Decision Making Tool for Dynamic Kill Operation

    E-Print Network [OSTI]

    Haghshenas, Arash

    2013-04-24T23:59:59.000Z

    , outcomes of blowouts are unknown and should be studied before starting an operation. Plans should be available to prevent blowouts or provide safe and secure ways of controlling the well before the drilling operation starts. The plan should include...

  10. A Robust Four-Fluid Transient Flow Simulator as an Analysis and Decision Making Tool for Dynamic Kill Operation

    E-Print Network [OSTI]

    Haghshenas, Arash

    2013-04-24T23:59:59.000Z

    The worst scenario of drilling operation is blowout which is uncontrolled flow of formation fluid into the wellbore. Blowouts result in environmental damage with potential risk of injuries and fatalities. Although not all ...

  11. Molecular Dynamic Simulation of Thermo-Mechanical Properties of Ultra-Thin Poly(methyl methacrylate) Films

    E-Print Network [OSTI]

    Silva Hernandez, Carlos Ardenis A.

    2011-08-08T23:59:59.000Z

    MOLECULAR DYNAMIC SIMULATION OF THERMO-MECHANICAL PROPERTIES OF ULTRA-THIN POLY(METHYL METHACRYLATE) FILMS A Dissertation by CARLOS ARDENIS SILVA HERNANDEZ Submitted to the Office of Graduate Studies of Texas A&M University... A Dissertation by CARLOS ARDENIS SILVA HERNANDEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Co-Chairs of Committee...

  12. Simulation of hydrology and population dynamics of Anopheles mosquitoes around the Koka Reservoir in Ethiopia

    E-Print Network [OSTI]

    Endo, Noriko S.M. Massachusetts Institute of Technology

    2014-01-01T23:59:59.000Z

    This thesis applies the HYDRology, Entomology and MAlaria Transmission Simulator (HYDREMATS) to the environment around a water resources reservoir in Ethiopia. HYDREMATS was modified to simulate the local hydrology and the ...

  13. MOLECULAR DYNAMICS SIMULATION OF HETEROGENEOUS NUCLEATION OF LIQUID DROPLET ON SOLID SURFACE

    E-Print Network [OSTI]

    Maruyama, Shigeo

    such as the quantum dot generation. We have simulated the equilibrium liquid droplet on the solid surface simulation on the bubble nucleation process on the solid surface [2]. In the meantime, direct molecular

  14. DEVELOPMENT OF A QUANTITATIVE MEASURE OF THE FUNCTIONALITY OF FRAME WALLS ENHANCED WITH PHASE CHANGE MATERIALS USING A DYNAMIC WALL SIMULATOR

    E-Print Network [OSTI]

    Evers, Angela C.

    2008-07-25T23:59:59.000Z

    Frame walls enhanced with phase change materials (paraffin-based, hydrated salt-based, and eutectic) mixed in cellulose insulation were developed and tested. The frame walls were heated and allowed to cool in a dynamic wall simulator that replicated...

  15. Software interoperability for energy simulation

    E-Print Network [OSTI]

    Hitchcock, Robert J.

    2002-01-01T23:59:59.000Z

    Tools, in Building Energy Simulation User News, Vol. 22,Interoperability for Energy Simulation Robert J. Hitchcock,Interoperability for Energy Simulation Robert J. Hitchcock,

  16. Best practices for system dynamics model design and construction with powersim studio.

    SciTech Connect (OSTI)

    Malczynski, Leonard A.

    2011-06-01T23:59:59.000Z

    This guide addresses software quality in the construction of Powersim{reg_sign} Studio 8 system dynamics simulation models. It is the result of almost ten years of experience with the Powersim suite of system dynamics modeling tools (Constructor and earlier Studio versions). It is a guide that proposes a common look and feel for the construction of Powersim Studio system dynamics models.

  17. Challenges in Simulation of Aerodynamics, Hydrodynamics, and Mooring-Line Dynamics of Floating Offshore Wind Turbines

    SciTech Connect (OSTI)

    Matha, D.; Schlipf, M.; Cordle, A.; Pereira, R.; Jonkman, J.

    2011-10-01T23:59:59.000Z

    This paper presents the current major modeling challenges for floating offshore wind turbine design tools and describes aerodynamic and hydrodynamic effects due to rotor and platform motions and usage of non-slender support structures.

  18. Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation

    SciTech Connect (OSTI)

    Mackin, Peter; Daschmans, R.; Williams, B.; Haney, B.; Hung, R.; Ellis, J.

    2010-12-20T23:59:59.000Z

    Utility Systems Efficiencies, Inc. was tasked by Lawrence Berkeley National Laboratory (LBNL) to conduct dynamic simulation studies of the three U.S. interconnections (Eastern, Western, and Texas). The simulations were prepared in support of LBNL's project for the Federal Energy Regulatory Commission to study frequency-response-related issues that must be addressed to operate the power system reliably with large amounts of variable renewable generation. The objective of the simulation studies of each interconnection was to assess the effects of different amounts of wind generation on frequency behavior of each interconnection following a sudden loss of generation. The scenarios created to study these effects considered an operating circumstance in which system load is at or close to its minimum. The event studied was the sudden loss of the largest amount of generation recorded within each interconnection. The simulations calculated the impact of this event on interconnection frequency for three levels of wind generation. In addition to varying the amount of wind generation, the simulations varied the amount of operating reserves between a high level representative of current operating practices and a low level representative of the minimum required by present operating rules.

  19. User Guide for PV Dynamic Model Simulation Written on PSCAD Platform

    SciTech Connect (OSTI)

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2014-11-01T23:59:59.000Z

    This document describes the dynamic photovoltaic model developed by the National Renewable Energy Laboratory and is intended as a guide for users of these models.

  20. A low diffusive Lagrange-remap scheme for the simulation of violent air-water free-surface flows.

    E-Print Network [OSTI]

    Boyer, Edmond

    . The evolution of the interfaces between phases and the consecutive complex dynamics need to be simulatedA low diffusive Lagrange-remap scheme for the simulation of violent air-water free-surface flows. Introduction Simulation of free surface flows knows an increasing interest as an essential predictive tool

  1. Evaluating the learning effectiveness of using simulations in software project management education: results from a twice replicated experiment

    E-Print Network [OSTI]

    Krivobokova, Tatyana

    Evaluating the learning effectiveness of using simulations in software project management education replicated experiment that evaluates the learning effectiveness of using a process simulation model a System Dynamics simulation model, the control group used the well-known COCOMO model as a predictive tool

  2. advanced beam-dynamics simulation: Topics by E-print Network

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

    . . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...

  3. A localised subgrid scale model for fluid dynamical simulations in astrophysics II: Application to type Ia supernovae

    E-Print Network [OSTI]

    W. Schmidt; J. C. Niemeyer; W. Hillebrandt; F. K. Roepke

    2006-01-23T23:59:59.000Z

    The dynamics of the explosive burning process is highly sensitive to the flame speed model in numerical simulations of type Ia supernovae. Based upon the hypothesis that the effective flame speed is determined by the unresolved turbulent velocity fluctuations, we employ a new subgrid scale model which includes a localised treatment of the energy transfer through the turbulence cascade in combination with semi-statistical closures for the dissipation and non-local transport of turbulence energy. In addition, subgrid scale buoyancy effects are included. In the limit of negligible energy transfer and transport, the dynamical model reduces to the Sharp-Wheeler relation. According to our findings, the Sharp-Wheeler relation is insuffcient to account for the complicated turbulent dynamics of flames in thermonuclear supernovae. The application of a co-moving grid technique enables us to achieve very high spatial resolution in the burning region. Turbulence is produced mostly at the flame surface and in the interior ash regions. Consequently, there is a pronounced anisotropy in the vicinity of the flame fronts. The localised subgrid scale model predicts significantly enhanced energy generation and less unburnt carbon and oxygen at low velocities compared to earlier simulations.

  4. Results of a Neutronic Simulation of HTR-Proteus Core 4.2 using PEBBED and other INL Reactor Physics Tools: FY-09 Report

    SciTech Connect (OSTI)

    Hans D. Gougar

    2009-08-01T23:59:59.000Z

    The Idaho National Laboratorys deterministic neutronics analysis codes and methods were applied to the computation of the core multiplication factor of the HTR-Proteus pebble bed reactor critical facility. A combination of unit cell calculations (COMBINE-PEBDAN), 1-D discrete ordinates transport (SCAMP), and nodal diffusion calculations (PEBBED) were employed to yield keff and flux profiles. Preliminary results indicate that these tools, as currently configured and used, do not yield satisfactory estimates of keff. If control rods are not modeled, these methods can deliver much better agreement with experimental core eigenvalues which suggests that development efforts should focus on modeling control rod and other absorber regions. Under some assumptions and in 1D subcore analyses, diffusion theory agrees well with transport. This suggests that developments in specific areas can produce a viable core simulation approach. Some corrections have been identified and can be further developed, specifically: treatment of the upper void region, treatment of inter-pebble streaming, and explicit (multiscale) transport modeling of TRISO fuel particles as a first step in cross section generation. Until corrections are made that yield better agreement with experiment, conclusions from core design and burnup analyses should be regarded as qualitative and not benchmark quality.

  5. Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures

    E-Print Network [OSTI]

    Goddard III, William A.

    Early maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures Elodie Salmon a , Adri C.T. van Duin b , Franois Lorant Brown coal using the ReaxFF reactive force field. We find that these reactive MD simulations

  6. Parallel contact detection algorithm for transient solid dynamics simulations using PRONTO3D

    SciTech Connect (OSTI)

    Attaway, S.W.; Hendrickson, B.A.; Plimpton, S.J. [and others

    1996-09-01T23:59:59.000Z

    An efficient, scalable, parallel algorithm for treating material surface contacts in solid mechanics finite element programs has been implemented in a modular way for MIMD parallel computers. The serial contact detection algorithm that was developed previously for the transient dynamics finite element code PRONTO3D has been extended for use in parallel computation by devising a dynamic (adaptive) processor load balancing scheme.

  7. Ab initio molecular dynamics simulations of ion-solid interactions in Gd2Zr2O7 and Gd2Ti2O7

    SciTech Connect (OSTI)

    Wang, X J [University of Electronic Science and Technology of China (UESTC); Xiao, Haiyan [University of Tennessee, Knoxville (UTK); Zu, X T [University of Electronic Science and Technology of China (UESTC); Zhang, Yanwen [ORNL; Weber, William J [ORNL

    2013-01-01T23:59:59.000Z

    The development of ab initio molecular dynamics (AIMD) method has made it a powerful tool in describing ion-solid interactions in materials, with identification determination of threshold displacement energies with ab initio accuracy, and prediction of new mechanism for defect generation and new defective states that are different from classical molecular dynamics (MD) simulations. In the present work, this method is employed to study the low energy recoil events in Gd2Zr2O7 and Gd2Ti2O7. The weighted average threshold displacement energies in Gd2Zr2O7 are determined to be 38.8 eV for Gd, 41.4 eV for Zr, 18.6 eV for O48f, and 15.6 eV for O8b, which are smaller than the respective values of 41.8, >53.8, 22.6 and 16.2 eV in Gd2Ti2O7. It reveals that all the ions in Gd2Zr2O7 are more easily displaced than those in Gd2Ti2O7, and anion order-disorder are more likely to be involved in the displacement events than cation disordering. The average charge transfer from the primary knock-on atom to its neighbors is estimated to be ~0.15, ~0.11-0.27 and ~0.1-0.13 |e| for Gd, Zr (or Ti), and O, respectively. Negligence of the charge transfer in the interatomic potentials may result in the larger threshold displacement energies in classical MD.

  8. Anharmonic lattice dynamics of Ag2O studied by inelastic neutron scattering and first-principles molecular dynamics simulations

    SciTech Connect (OSTI)

    Lan, Tian [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Li, Chen [ORNL] [ORNL; Niedziela, Jennifer L [ORNL] [ORNL; Smith, Hillary [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Abernathy, Douglas L [ORNL] [ORNL; Rossman, George [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena; Fultz, B. [California Institute of Technology, Pasadena] [California Institute of Technology, Pasadena

    2014-01-01T23:59:59.000Z

    Inelastic neutron scattering measurements on silver oxide (Ag2O) with the cuprite structure were performed at temperatures from 40 to 400 K, and Fourier transform far-infrared spectra were measured from 100 to 300 K. The measured phonon densities of states and the infrared spectra showed unusually large energy shifts with temperature, and large linewidth broadenings. First principles molecular dynamics (MD) calculations were performed at various temperatures, successfully accounting for the negative thermal expansion (NTE) and local dynamics. Using the Fourier-transformed velocity autocorrelation method, the MD calculations reproduced the large anharmonic effects of Ag2O, and were in excellent agreement with the neutron scattering data. The quasiharmonic approximation (QHA) was less successful in accounting for much of the phonon behavior. The QHA could account for some of the NTE below 250 K, although not at higher temperatures. Strong anharmonic effects were found for both phonons and for the NTE. The lifetime broadenings of Ag2O were explained by anharmonic perturbation theory, which showed rich interactions between the Ag-dominated modes and the O-dominated modes in both up- and down-conversion processes.

  9. A new shared-memory programming paradigm for molecular dynamics simulations on the Intel Paragon

    SciTech Connect (OSTI)

    D`Azevedo, E.F.; Romine, C.H.

    1994-12-01T23:59:59.000Z

    This report describes the use of shared memory emulation with DOLIB (Distributed Object Library) to simplify parallel programming on the Intel Paragon. A molecular dynamics application is used as an example to illustrate the use of the DOLIB shared memory library. SOTON-PAR, a parallel molecular dynamics code with explicit message-passing using a Lennard-Jones 6-12 potential, is rewritten using DOLIB primitives. The resulting code has no explicit message primitives and resembles a serial code. The new code can perform dynamic load balancing and achieves better performance than the original parallel code with explicit message-passing.

  10. Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation

    SciTech Connect (OSTI)

    Arkundato, Artoto [Physics Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Su'ud, Zaki [Physics Department, Faculty of Mathematical and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung (Indonesia); Sudarko [Chemistry Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Shafii, Mohammad Ali [Physics Department, Faculty of Mathematical and Natural Sciences, Andalas University, Padang (Indonesia); Celino, Massimo [ENEA, CR Casaccia, Via Anguillarese 301, Rome (Italy)

    2014-09-30T23:59:59.000Z

    Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

  11. Trends in Ln(III) Sorption to Quartz Assessed by Molecular Dynamics Simulations and Laser Induced Flourescence Studies

    SciTech Connect (OSTI)

    Kuta, Jadwiga; Wander, Matthew C F.; Wang, Zheming; Jiang, Siduo; Wall, Nathalie; Clark, Aurora E.

    2011-11-08T23:59:59.000Z

    Molecular dynamics simulations were performed to examine trends in trivalent lanthanide [Ln(III)] sorption to quartz surface SiOH0 and SiO- sites across the 4f period. Complementary laser induced fluorescence studies examined Eu(III) sorption to quartz at varying ionic strength such that the surface sorbed species could be extrapolated at zero ionic strength, the conditions under which the simulations are performed. This allowed for direct comparison of the data, enabling a molecular understanding of the surface sorbed species and the role of the ion surface charge density upon the interfacial reactivity. Thus, this combined theoretical and experimental approach aids in the prediction of the fate of trivalent radioactive contaminants at temporary and permanent nuclear waste storage sites. Potential of mean force molecular dynamics, as well as simulations of pre-sorbed Ln(III) species agrees with the spectroscopic study of Eu(III) sorption, indicating that strongly bound inner-sphere complexes are formed upon sorption to an SiO- site. The coordination shell of the ion contains 6-7 waters of hydration and it is predicted that surface OH groups dissociate from the quartz and bind within the inner coordination shell of Eu(III). Molecular simulations predict less-strongly bound inner2 sphere species in early lanthanides and more strongly bound species in late lanthanides, following trends in the ionic radius of the 4f ions. The participation of surface dissociated OHgroups within the inner coordination shell of the Ln(III) ion is, however, consistent across the series studied. Sorption to a fully protonated quartz surface is not predicted to be favorable by any Ln(III), except perhaps Lu.

  12. BEAM DYNAMICS SIMULATIONS FOR A DC GUN BASED INJECTOR FOR PERL...

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

    DC gun. The schematic layout of a PERL DC gun based injector and its preliminary beam dynamics are presented in this paper. The transverse and longitudinal emittance of photo-...

  13. Stokesian dynamic simulations and analyses of interfacial and bulk colloidal fluids

    E-Print Network [OSTI]

    Anekal, Samartha Guha

    2006-10-30T23:59:59.000Z

    , and hydrodynamic forces to model dynamics of colloidal dispersions. In addition, we develop theoretical expressions for quantifying self-diffusion in colloids interacting via different particle-particle and particle-wall potentials. Specifically, we have used...

  14. Simulation of the dynamic behaviour of a geared transmission on hydrodynamic journal bearings

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and bearings, oil injection, thermal effects, non Newtonian lubricant, etc. On the other hand, the dynamic whose reactions are calculated solving the lubrication equation presented in [3] under the short bearing

  15. Dynamics of a globular protein and its hydration water studied by neutron scattering and MD simulations

    E-Print Network [OSTI]

    Chen, Sow-Hsin

    2010-01-01T23:59:59.000Z

    This review article describes our neutron scattering experiments made in the past four years for the understanding of the single-particle (hydrogen atom) dynamics of a protein and its hydration water and the strong coupling ...

  16. On the Consistency of Approximate Quantum Dynamics Simulation Methods for Vibrational Spectra in the Condensed Phase

    E-Print Network [OSTI]

    Rossi, Mariana; Paesani, Francesco; Bowman, Joel; Ceriotti, Michele

    2014-01-01T23:59:59.000Z

    Including quantum mechanical effects on the dynamics of nuclei in the condensed phase is challenging, because the complexity of exact methods grows exponentially with the number of quantum degrees of freedom. Efforts to circumvent these limitations can be traced down to two approaches: methods that treat a small subset of the degrees of freedom with rigorous quantum mechanics, considering the rest of the system as a static or classical environment, and methods that treat the whole system quantum mechanically, but using approximate dynamics. Here we perform a systematic comparison between these two philosophies for the description of quantum effects in vibrational spectroscopy, taking the Embedded Local Monomer (LMon) model and a mixed quantum-classical (MQC) model as representatives of the first family of methods, and centroid molecular dynamics (CMD) and thermostatted ring polymer molecular dynamics (TRPMD) as examples of the latter. We use as benchmarks D$_2$O doped with HOD and pure H$_2$O at three distinc...

  17. A PARTICLE SIMULATION CODE FOR LONGITUDINAL DYNAMICS OF HEAVY ION BEAMS

    E-Print Network [OSTI]

    Sternlieb, A.

    2010-01-01T23:59:59.000Z

    Energy under Contract No. W-7405-ENG-48. Fiji. 1: Flow ChartEnergy under Contract W-7405-ENG-48 LBL-12205 HI-FAN-144 Aunder Contract No. W-7405-ENG-48. A Particle Simulation Code

  18. An efficient algorithm for blade loss simulations applied to a high-order rotor dynamics problem

    E-Print Network [OSTI]

    Parthasarathy, Nikhil Kaushik

    2004-09-30T23:59:59.000Z

    In this thesis, a novel approach is presented for blade loss simulation of an aircraft gas turbine rotor mounted on rolling element bearings with squeeze film dampers, seal rub and enclosed in a flexible housing. The modal truncation augmentation...

  19. A Finite Element-Multibody Dynamics Co-simulation Methodology Applied to FAST

    E-Print Network [OSTI]

    Suryakumar, Vishvas Samuel

    2013-05-02T23:59:59.000Z

    . To synchronize the coupling variables, a Gauss-Seidel type iterative algorithm is used. The resulting fixed-point iterations are accelerated using Aitkens adaptive relaxation technique. The methodology is evaluated for FAST, a wind turbine aeroelastic simulation...

  20. Author's personal copy Experimental validation of large-scale simulations of dynamic fracture along

    E-Print Network [OSTI]

    Rosakis, Ares J.

    in monolithic homo- geneous brittle solids and along weak interfaces between homo- geneous solids has also been for the fitting of parameters. Then, the results of these simulations are validated against those of experiments