Sample records for advanced modeling simulation

  1. Advanced Space Shuttle simulation model

    NASA Technical Reports Server (NTRS)

    Tatom, F. B.; Smith, S. R.

    1982-01-01

    A non-recursive model (based on von Karman spectra) for atmospheric turbulence along the flight path of the shuttle orbiter was developed. It provides for simulation of instantaneous vertical and horizontal gusts at the vehicle center-of-gravity, and also for simulation of instantaneous gusts gradients. Based on this model the time series for both gusts and gust gradients were generated and stored on a series of magnetic tapes, entitled Shuttle Simulation Turbulence Tapes (SSTT). The time series are designed to represent atmospheric turbulence from ground level to an altitude of 120,000 meters. A description of the turbulence generation procedure is provided. The results of validating the simulated turbulence are described. Conclusions and recommendations are presented. One-dimensional von Karman spectra are tabulated, while a discussion of the minimum frequency simulated is provided. The results of spectral and statistical analyses of the SSTT are presented.

  2. Center for Advanced Modeling and Simulation Intern

    SciTech Connect

    Gertman, Vanessa

    2010-01-01

    Some interns just copy papers and seal envelopes. Not at INL! Check out how Vanessa Gertman, an INL intern working at the Center for Advanced Modeling and Simulation, spent her summer working with some intense visualization software. Lots more content like this is available at INL's facebook page http://www.facebook.com/idahonationallaboratory.

  3. Advanced Modeling, Simulation and Analysis (AMSA) Capability Roadmap Progress Review

    NASA Technical Reports Server (NTRS)

    Antonsson, Erik; Gombosi, Tamas

    2005-01-01

    Contents include the following: NASA capability roadmap activity. Advanced modeling, simulation, and analysis overview. Scientific modeling and simulation. Operations modeling. Multi-special sensing (UV-gamma). System integration. M and S Environments and Infrastructure.

  4. ADVANCED UTILITY SIMULATION MODEL, MODEL OPERATIONS (VERSION 1.0)

    EPA Science Inventory

    The report is one of several in a series describing the initial development--by the Universities Research Group on Energy (URGE)--of the Advanced Utility Simulation Model (AUSM), one of four stationary source emission and control cost forecasting models developed by the U.S. EPA ...

  5. Advances in modeling and simulation of vacuum electronic devices

    Microsoft Academic Search

    THOMAS M. ANTONSEN; ALFRED A. MONDELLI; BARUCH LEVUSH; JOHN P. VERBONCOEUR; C. K. Birdsall

    1999-01-01

    Recent advances in the modeling and simulation of vacuum electronic devices are reviewed. Design of these devices makes use of a variety of physical models and numerical code types. Progress in the development of these models and codes is outlined and illustrated with specific examples. The state of the art in device simulation is evolving to the point such that

  6. Advances in NLTE Modeling for Integrated Simulations

    SciTech Connect

    Scott, H A; Hansen, S B

    2009-07-08

    The last few years have seen significant progress in constructing the atomic models required for non-local thermodynamic equilibrium (NLTE) simulations. Along with this has come an increased understanding of the requirements for accurately modeling the ionization balance, energy content and radiative properties of different elements for a wide range of densities and temperatures. Much of this progress is the result of a series of workshops dedicated to comparing the results from different codes and computational approaches applied to a series of test problems. The results of these workshops emphasized the importance of atomic model completeness, especially in doubly excited states and autoionization transitions, to calculating ionization balance, and the importance of accurate, detailed atomic data to producing reliable spectra. We describe a simple screened-hydrogenic model that calculates NLTE ionization balance with surprising accuracy, at a low enough computational cost for routine use in radiation-hydrodynamics codes. The model incorporates term splitting, {Delta}n = 0 transitions, and approximate UTA widths for spectral calculations, with results comparable to those of much more detailed codes. Simulations done with this model have been increasingly successful at matching experimental data for laser-driven systems and hohlraums. Accurate and efficient atomic models are just one requirement for integrated NLTE simulations. Coupling the atomic kinetics to hydrodynamics and radiation transport constrains both discretizations and algorithms to retain energy conservation, accuracy and stability. In particular, the strong coupling between radiation and populations can require either very short timesteps or significantly modified radiation transport algorithms to account for NLTE material response. Considerations such as these continue to provide challenges for NLTE simulations.

  7. Gasification CFD Modeling for Advanced Power Plant Simulations

    Microsoft Academic Search

    S. E. Zitney; C. P. Guenther

    2005-01-01

    In this paper we have described recent progress on developing CFD models for two commercial-scale gasifiers, including a two-stage, coal slurry-fed, oxygen-blown, pressurized, entrained-flow gasifier and a scaled-up design of the PSDF transport gasifier. Also highlighted was NETLs Advanced Process Engineering Co-Simulator for coupling high-fidelity equipment models with process simulation for the design, analysis, and optimization of advanced power plants.

  8. ADVANCED UTILITY SIMULATION MODEL DESCRIPTION OF MODIFICATIONS TO THE STATE LEVEL MODEL (VERSION 3.0)

    EPA Science Inventory

    The report documents modifications to the state level model portion of the Advanced Utility Simulation Model (AUSM), one of four stationary source emission and control cost forecasting models developed for the National Acid Precipitation Assessment Program (NAPAP). The AUSM model...

  9. Simulation approach for modeling single event upsets on advanced CMOS SRAMS

    Microsoft Academic Search

    R. L. Johnson Jr.; S. E. Diehl-Nagle; J. R. Hauser

    1985-01-01

    A pair of simulation routines have been developed in order to accurately model single event upsets in advanced CMOS SRAMs. Simulation problems addressed are those associated with modelling minority carrier charge storage and multilayer charge collection effects. As a result, the decoupling resistance to harden the cell for an advanced CMOS structure has been accurately estimated and a simulation technique

  10. Modelling and Simulation of the Advanced Plasma Source

    SciTech Connect

    Schroeder, Benjamin; Peter, Ralf [Lehrstuhl fuer Theoretische Elektrotechnik, Ruhr-Universitaet Bochum, Universitaetsstrasse 150, Bochum 44801 (Germany); Harhausen, Jens; Ohl, Andreas [INP Greifswald e.V., Felix - Hausdorff - Str. 2, Greifswald 17489 (Germany)

    2011-08-15

    Plasma ion assisted-deposition (PIAD) is a combination of conventional thermal evaporation deposition and plasma-beam surface modification; it serves as a well-established technology for the creation of high quality coatings on mirrors, lenses, and other optical devices. It is closely related to ion-assisted deposition to the extent that electrons preserve quasineutrality of the ion beam. This paper investigates the Advanced Plasma Source (APS), a plasma beam source employed for PIAD. A field enhanced glow discharge generates a radially expanding plasma flow with an ion energy of about 80-120 eV. Charge exchange collisions with the neutral background gas (pressure 0.1 Pa and below) produce a cold secondary plasma, which expands as well. A model is developed which describes the primary ions by a simplified Boltzmann equation, the secondary ions by the equations of continuity and momentum balance, and the electrons by the condition of Boltzmann equilibrium. Additionally, quasineutrality is assumed. The model can be reduced to a single nonlinear differential equation for the velocity of the secondary ions, which has several removable singularities and one essential singularity, identified as the Bohm singularity. Solving the model yields macroscopic plasma features, such as fluxes, densities, and the electrical field. An add-on Monte-Carlo simulation is employed to calculate the ion energy distribution function at the substrate. All results compare well to experiments conducted at a commercial APS system.

  11. Advanced 3D Photocathode Modeling and Simulations Final Report

    SciTech Connect

    Dimitre A Dimitrov; David L Bruhwiler

    2005-06-06

    High brightness electron beams required by the proposed Next Linear Collider demand strong advances in photocathode electron gun performance. Significant improvement in the production of such beams with rf photocathode electron guns is hampered by the lack high-fidelity simulations. The critical missing piece in existing gun codes is a physics-based, detailed treatment of the very complex and highly nonlinear photoemission process.

  12. Recent Advances in Underwater Acoustic Modelling and Simulation

    NASA Astrophysics Data System (ADS)

    ETTER, P. C.

    2001-02-01

    A comprehensive review of international developments in underwater acoustic modelling is used to construct an updated technology baseline containing 107 propagation models, 16 noise models, 17 reverberation models and 25 sonar performance models. This updated technology baseline represents a 30% increase over a previous baseline published in 1996. When executed in higher-level simulations, these models can generate predictive and diagnostic outputs that are useful to acoustical oceanographers or sonar technologists in the analysis of complex systems operating in the undersea environment. Recent modelling developments described in the technical literature suggest two principal areas of application: low-frequency, inverse acoustics in deep water; and high-frequency, bottom-interacting acoustics in coastal regions. Rapid changes in global geopolitics have opened new avenues for collaboration, thereby facilitating the transfer of modelling and simulation technologies among members of the international community. This accelerated technology transfer has created new imperatives for international standards in modelling and simulation architectures. National and international activities to promote interoperability among modelling and simulation efforts in government, industry and academia are reviewed and discussed.

  13. Advances in Modeling and Simulation of Grinding Processes

    Microsoft Academic Search

    E. Brinksmeier; J. C. Aurich; E. Govekar; C. Heinzel; H.-W. Hoffmeister; F. Klocke; J. Peters; R. Rentsch; D. J. Stephenson; E. Uhlmann; K. Weinert; M. Wittmann

    2006-01-01

    In the last decade the relevance of modeling and simulation of grinding processes has significantly risen which is caused by industrial needs and is indicated by the number of publications and research activities in this area. This keynote paper results from a collaborative work within the STC G and gives an overview of the current state of the art in

  14. Advanced modelling of failure mechanisms in aluminium sheet forming simulation

    Microsoft Academic Search

    Holger Aretz; Stefan Keller; Rolf Vogt; Olaf Engler

    2009-01-01

    In this paper novel and efficient approaches to model localized necking and ductile fracture in sheet forming simulation using\\u000a the finite element method are presented. The stress-based forming limit curve is used to detect localized necking. Post-necking\\u000a is captured using a new concept called accelerated plastic thinning. A simple ductile fracture model was developed. Various\\u000a application examples demonstrate the capabilities

  15. Advancing botnet modeling techniques for military and security simulations

    NASA Astrophysics Data System (ADS)

    Banks, Sheila B.; Stytz, Martin R.

    2011-06-01

    Simulation environments serve many purposes, but they are only as good as their content. One of the most challenging and pressing areas that call for improved content is the simulation of bot armies (botnets) and their effects upon networks and computer systems. Botnets are a new type of malware, a type that is more powerful and potentially dangerous than any other type of malware. A botnet's power derives from several capabilities including the following: 1) the botnet's capability to be controlled and directed throughout all phases of its activity, 2) a command and control structure that grows increasingly sophisticated, and 3) the ability of a bot's software to be updated at any time by the owner of the bot (a person commonly called a bot master or bot herder.) Not only is a bot army powerful and agile in its technical capabilities, a bot army can be extremely large, can be comprised of tens of thousands, if not millions, of compromised computers or it can be as small as a few thousand targeted systems. In all botnets, their members can surreptitiously communicate with each other and their command and control centers. In sum, these capabilities allow a bot army to execute attacks that are technically sophisticated, difficult to trace, tactically agile, massive, and coordinated. To improve our understanding of their operation and potential, we believe that it is necessary to develop computer security simulations that accurately portray bot army activities, with the goal of including bot army simulations within military simulation environments. In this paper, we investigate issues that arise when simulating bot armies and propose a combination of the biologically inspired MSEIR infection spread model coupled with the jump-diffusion infection spread model to portray botnet propagation.

  16. Advanced Techniques for Reservoir Simulation and Modeling of Non-Conventional Wells

    SciTech Connect

    Durlofsky, Louis J.

    2000-08-28

    This project targets the development of (1) advanced reservoir simulation techniques for modeling non-conventional wells; (2) improved techniques for computing well productivity (for use in reservoir engineering calculations) and well index (for use in simulation models), including the effects of wellbore flow; and (3) accurate approaches to account for heterogeneity in the near-well region.

  17. ADVANCED UTILITY SIMULATION MODEL, REPORT OF SENSITIVITY TESTING, CALIBRATION, AND MODEL OUTPUT COMPARISONS (VERSION 3.0)

    EPA Science Inventory

    The report gives results of activities relating to the Advanced Utility Simulation Model (AUSM): sensitivity testing. comparison with a mature electric utility model, and calibration to historical emissions. The activities were aimed at demonstrating AUSM's validity over input va...

  18. A simulation model with endogenous technical advance: Information technology and increasing returns from research

    Microsoft Academic Search

    Gordon R Richards

    2002-01-01

    This paper builds a simulation model in which technological advance is stochastic, and largely endogenous. Technology consists of two main components, research and development (R&D) and residual technical advance. R&D comprises a government-funded component, which is treated as exogenous, and a component funded by private industry, which is determined within the model. Industry-funded R&D is modeled as analogous to a

  19. ADVANCED UTILITY SIMULATION MODEL, ENERGY AND EMPLOYMENT IMPACTS MODULE (VERSION 1.0)

    EPA Science Inventory

    The report is one of an 11-volume series that describes the initial development of the Advanced Utility Simulation Model (AUSM), one of four stationary source emission and control cost forecasting models developed in 1984 for the National Acid Precipitation Assessment Program (NA...

  20. Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC)

    Microsoft Academic Search

    Schultz; Peter Andrew

    2011-01-01

    The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal

  1. Modeling and simulation of manufacturing processes of advanced composite materials

    NASA Astrophysics Data System (ADS)

    Lee, Woo I.; Springer, George S.

    Models for autoclave curing of thermosetting matrix composites are briefly described along with models of manufacturing process models for thermoplastic matrix composites. These models can be used to obtain optimum cure cycles of composite materials. They are particularly useful since the cure cycle must be modified to account for the effect of internal heat generation at the thickness of composite laminate changes. They can be indispensable tools in finding appropriate rules for optimum cure cycles via expert systems.

  2. Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)

    Microsoft Academic Search

    Kimberlyn C. Mousseau

    2011-01-01

    The Nuclear Energy Computational Fluid Dynamics Advanced Modeling and Simulation (NE-CAMS) system is being developed at the Idaho National Laboratory (INL) in collaboration with Bettis Laboratory, Sandia National Laboratory (SNL), Argonne National Laboratory (ANL), Utah State University (USU), and other interested parties with the objective of developing and implementing a comprehensive and readily accessible data and information management system for

  3. CHARMM-GUI PDB manipulator for advanced modeling and simulations of proteins containing nonstandard residues.

    PubMed

    Jo, Sunhwan; Cheng, Xi; Islam, Shahidul M; Huang, Lei; Rui, Huan; Zhu, Allen; Lee, Hui Sun; Qi, Yifei; Han, Wei; Vanommeslaeghe, Kenno; MacKerell, Alexander D; Roux, Benoît; Im, Wonpil

    2014-01-01

    CHARMM-GUI, http://www.charmm-gui.org, is a web-based graphical user interface to prepare molecular simulation systems and input files to facilitate the usage of common and advanced simulation techniques. Since it is originally developed in 2006, CHARMM-GUI has been widely adopted for various purposes and now contains a number of different modules designed to setup a broad range of simulations including free energy calculation and large-scale coarse-grained representation. Here, we describe functionalities that have recently been integrated into CHARMM-GUI PDB Manipulator, such as ligand force field generation, incorporation of methanethiosulfonate spin labels and chemical modifiers, and substitution of amino acids with unnatural amino acids. These new features are expected to be useful in advanced biomolecular modeling and simulation of proteins. PMID:25443960

  4. An advanced conceptual aircraft simulator

    Microsoft Academic Search

    G. G. Kupermann; D. L. Wilson

    1988-01-01

    The development of a proposed multiseat advanced aircraft man-in-the-loop simulation facility is briefly described. This facility, called the strategic avionics battle-management evaluation and research (SABER) simulation facility, is based on distributed graphics processors hosted on a central mainframe computer. The mainframe supports aircraft flight models, weapon flyout models, and simulation data storage and data collection. The graphics processors, exploiting downloaded

  5. The Advanced Modeling, Simulation and Analysis Capability Roadmap Vision for Engineering

    NASA Technical Reports Server (NTRS)

    Zang, Thomas; Lieber, Mike; Norton, Charles; Fucik, Karen

    2006-01-01

    This paper summarizes a subset of the Advanced Modeling Simulation and Analysis (AMSA) Capability Roadmap that was developed for NASA in 2005. The AMSA Capability Roadmap Team was chartered to "To identify what is needed to enhance NASA's capabilities to produce leading-edge exploration and science missions by improving engineering system development, operations, and science understanding through broad application of advanced modeling, simulation and analysis techniques." The AMSA roadmap stressed the need for integration, not just within the science, engineering and operations domains themselves, but also across these domains. Here we discuss the roadmap element pertaining to integration within the engineering domain, with a particular focus on implications for future observatory missions. The AMSA products supporting the system engineering function are mission information, bounds on information quality, and system validation guidance. The Engineering roadmap element contains 5 sub-elements: (1) Large-Scale Systems Models, (2) Anomalous Behavior Models, (3) advanced Uncertainty Models, (4) Virtual Testing Models, and (5) space-based Robotics Manufacture and Servicing Models.

  6. Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC).

    SciTech Connect

    Schultz, Peter Andrew

    2011-12-01

    The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V&V) is required throughout the system to establish evidence-based metrics for the level of confidence in M&S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V&V challenge at the subcontinuum scale, an approach to incorporate V&V concepts into subcontinuum scale modeling and simulation (M&S), and a plan to incrementally incorporate effective V&V into subcontinuum scale M&S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.

  7. Advanced computers and simulation

    SciTech Connect

    Ryne, R.D.

    1993-06-01

    Accelerator physicists today have access to computers that are far more powerful than those available just 10 years ago. In the early 1980`s, desktop workstations performed less one million floating point operations per second (Mflops), and the realized performance of vector supercomputers was at best a few hundred Mflops. Today vector processing is available on the desktop, providing researchers with performance approaching 100 Mflops at a price that is measured in thousands of dollars. Furthermore, advances in Massively Parallel Processors (MPP) have made performance of over 10 gigaflops a reality, and around mid-decade MPPs are expected to be capable of teraflops performance. Along with advances in MPP hardware, researchers have also made significant progress in developing algorithms and software for MPPS. These changes have had, and will continue to have, a significant impact on the work of computational accelerator physicists. Now, instead of running particle simulations with just a few thousand particles, we can perform desktop simulations with tens of thousands of simulation particles, and calculations with well over 1 million particles are being performed on MPPs. In the area of computational electromagnetics, simulations that used to be performed only on vector supercomputers now run in several hours on desktop workstations, and researchers are hoping to perform simulations with over one billion mesh points on future MPPs. In this paper we will discuss the latest advances, and what can be expected in the near future, in hardware, software and applications codes for advanced simulation of particle accelerators.

  8. Advanced air quality modeling system for the simulation of photochemical ozone formation over North Carolina

    SciTech Connect

    Jang, C.; Wheeler, N.; Dolwick, P.; Olerud, D.; Houyoux, M. [MCNC-North Carolina Supercomputing Center, Research Triangle Park, NC (United States); Timin, B.; Lawrimore, J.; Holman, S. [North Carolina Dept. of Environment and Natural Resources, Raleigh, NC (United States). Div. of Air Quality; Jeffries, H. [Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Environmental Sciences and Engineering

    1998-12-31

    An advanced air quality modeling system is used to simulate the formation of photochemical oxidants, mainly ozone, over North Carolina. The objective of this modeling study is to successfully model the formation processes of ozone in North Carolina to lead to effective ozone control strategy developments for both 1-hour and 8-hour standards and eventually to address the particulate matter issue. The modeling system selected for this ongoing project is the North Carolina Supercomputing Center`s Environmental Decision Support System (EDSS), which evolved from a working prototype of EPA`s Third Generation Modeling System, or Models-3. The EDSS consists of three major modeling components : the Multiscale Air Quality SImulation Platform (MAQSIP) for chemistry/transport modeling, Mesoscale Model Version 5 (MM5) for meteorological modeling, and Sparse Matrix Operator Kernel Emissions (SMOKE) system for emission modeling. Two inner subdomains at 12-km and 4-km grid resolutions centered over Charlotte are nested inside a coarse domain at a 36-km resolution. Sixteen vertical layers with a denser grid at lower altitude are used to better resolve the mixing layer. The CB-IV chemistry mechanism with updated isoprene chemistry and radical-radical reactions is used to simulate the chemical transformations of reacting species. Preliminary results show that the MAQSIP has reasonably simulated the temporal and spatial distribution of ozone as compared to observations in the first 6-day episode during July 10--15, 1995. Improved ozone predictions are shown in the model using finer grid resolution. Various ozone sensitivity studies on the model inputs such as initial and boundary conditions and the existence of clouds are under testing. An innovative analysis tool for model evaluation and error detection, the Process Analysis method, is also applied to help understand the regulating processes that lead to formation of ozone.

  9. The Nuclear Energy Advanced Modeling and Simulation Enabling Computational Technologies FY09 Report

    SciTech Connect

    Diachin, L F; Garaizar, F X; Henson, V E; Pope, G

    2009-10-12

    In this document we report on the status of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Enabling Computational Technologies (ECT) effort. In particular, we provide the context for ECT In the broader NEAMS program and describe the three pillars of the ECT effort, namely, (1) tools and libraries, (2) software quality assurance, and (3) computational facility (computers, storage, etc) needs. We report on our FY09 deliverables to determine the needs of the integrated performance and safety codes (IPSCs) in these three areas and lay out the general plan for software quality assurance to meet the requirements of DOE and the DOE Advanced Fuel Cycle Initiative (AFCI). We conclude with a brief description of our interactions with the Idaho National Laboratory computer center to determine what is needed to expand their role as a NEAMS user facility.

  10. Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)

    SciTech Connect

    Kimberlyn C. Mousseau

    2011-10-01

    The Nuclear Energy Computational Fluid Dynamics Advanced Modeling and Simulation (NE-CAMS) system is being developed at the Idaho National Laboratory (INL) in collaboration with Bettis Laboratory, Sandia National Laboratory (SNL), Argonne National Laboratory (ANL), Utah State University (USU), and other interested parties with the objective of developing and implementing a comprehensive and readily accessible data and information management system for computational fluid dynamics (CFD) verification and validation (V&V) in support of nuclear energy systems design and safety analysis. The two key objectives of the NE-CAMS effort are to identify, collect, assess, store and maintain high resolution and high quality experimental data and related expert knowledge (metadata) for use in CFD V&V assessments specific to the nuclear energy field and to establish a working relationship with the U.S. Nuclear Regulatory Commission (NRC) to develop a CFD V&V database, including benchmark cases, that addresses and supports the associated NRC regulations and policies on the use of CFD analysis. In particular, the NE-CAMS system will support the Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program, which aims to develop and deploy advanced modeling and simulation methods and computational tools for reliable numerical simulation of nuclear reactor systems for design and safety analysis. Primary NE-CAMS Elements There are four primary elements of the NE-CAMS knowledge base designed to support computer modeling and simulation in the nuclear energy arena as listed below. Element 1. The database will contain experimental data that can be used for CFD validation that is relevant to nuclear reactor and plant processes, particularly those important to the nuclear industry and the NRC. Element 2. Qualification standards for data evaluation and classification will be incorporated and applied such that validation data sets will result in well-defined, well-characterized data. Element 3. Standards will be established for the design and operation of experiments for the generation of new validation data sets that are to be submitted to NE-CAMS that addresses the completeness and characterization of the dataset. Element 4. Standards will be developed for performing verification and validation (V&V) to establish confidence levels in CFD analyses of nuclear reactor processes; such processes will be acceptable and recognized by both CFD experts and the NRC.

  11. PSP: An Advanced Surface-Potential-Based MOSFET Model for Circuit Simulation

    Microsoft Academic Search

    Gennady Gildenblat; Xin Li; Weimin Wu; Hailing Wang; Amit Jha; Ronald van Langevelde; G. D. J. Smit; Andries J. Scholten; Dirk B. M. Klaassen

    2006-01-01

    This paper describes the latest and most advanced surface-potential-based model jointly developed by The Pennsylvania State University and Philips. Specific topics include model structure, mobility and velocity saturation description, further development and verification of symmetric linearization method, recent advances in the computational techniques for the surface potential, modeling of gate tunneling current, inclusion of the retrograde impurity profile, and noise

  12. Do Advanced Material Models Contribute to Accuracy in Industrial Sheet Forming Simulations?

    Microsoft Academic Search

    Boogaard van den A. H; H. H. Wisselink; J. Huetink

    2005-01-01

    The accuracy of material models can have a large impact on the overall accuracy of material forming simulations in general and sheet forming simulations in particular. For large strain plastic deformations, the material model usually consists of a yield function and a hardening relation, optionally including the influence of temperature and strain rate. In large-scale simulations it is favourable to

  13. ADVANCED UTILITY SIMULATION MODEL, MULTI-PERIOD MULTI-STATE MODULE DESIGN DOCUMENTATION (VERSION 1.0)

    EPA Science Inventory

    The report is one of 11 in a series describing the initial development of the Advanced Utility Simulation Model (AUSM) by the Universities Research Group on Energy (URGE) and its continued development by the Science Applications International Corporation (SAIC) research team. The...

  14. An architecture and model for cognitive engineering simulation analysis - Application to advanced aviation automation

    NASA Technical Reports Server (NTRS)

    Corker, Kevin M.; Smith, Barry R.

    1993-01-01

    The process of designing crew stations for large-scale, complex automated systems is made difficult because of the flexibility of roles that the crew can assume, and by the rapid rate at which system designs become fixed. Modern cockpit automation frequently involves multiple layers of control and display technology in which human operators must exercise equipment in augmented, supervisory, and fully automated control modes. In this context, we maintain that effective human-centered design is dependent on adequate models of human/system performance in which representations of the equipment, the human operator(s), and the mission tasks are available to designers for manipulation and modification. The joint Army-NASA Aircrew/Aircraft Integration (A3I) Program, with its attendant Man-machine Integration Design and Analysis System (MIDAS), was initiated to meet this challenge. MIDAS provides designers with a test bed for analyzing human-system integration in an environment in which both cognitive human function and 'intelligent' machine function are described in similar terms. This distributed object-oriented simulation system, its architecture and assumptions, and our experiences from its application in advanced aviation crew stations are described.

  15. Strategic Plan for Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS)

    Microsoft Academic Search

    Rich Johnson; Kimberlyn C. Mousseau; Hyung Lee

    2011-01-01

    NE-KAMS knowledge base will assist computational analysts, physics model developers, experimentalists, nuclear reactor designers, and federal regulators by: (1) Establishing accepted standards, requirements and best practices for V&V and UQ of computational models and simulations, (2) Establishing accepted standards and procedures for qualifying and classifying experimental and numerical benchmark data, (3) Providing readily accessible databases for nuclear energy related experimental

  16. Numerical flow simulation and efficiency prediction for axial turbines by advanced turbulence models

    NASA Astrophysics Data System (ADS)

    Jošt, D.; Škerlavaj, A.; Lipej, A.

    2012-11-01

    Numerical prediction of an efficiency of a 6-blade Kaplan turbine is presented. At first, the results of steady state analysis performed by different turbulence models for different operating regimes are compared to the measurements. For small and optimal angles of runner blades the efficiency was quite accurately predicted, but for maximal blade angle the discrepancy between calculated and measured values was quite large. By transient analysis, especially when the Scale Adaptive Simulation Shear Stress Transport (SAS SST) model with zonal Large Eddy Simulation (ZLES) in the draft tube was used, the efficiency was significantly improved. The improvement was at all operating points, but it was the largest for maximal discharge. The reason was better flow simulation in the draft tube. Details about turbulent structure in the draft tube obtained by SST, SAS SST and SAS SST with ZLES are illustrated in order to explain the reasons for differences in flow energy losses obtained by different turbulence models.

  17. Advanced layout fragmentation and simulation schemes for model-based OPCC

    NASA Astrophysics Data System (ADS)

    Word V, James; Torres, Andres; LaCour, Pat

    2005-05-01

    Traditional model based OPC software operates under a set of simple guiding principles. First, a design is fragmented into finitely sized segments, the sizes and numbers of which are limited by run-time and mask constraints. Within each fragment the intensity profile (aerial image) and edge-placement error (EPE) are calculated at a single location. Finally, the length of the entire fragment is moved to correct for the EPE at that location. This scheme has potential limitations in certain cases. For instance, cases where the aerial image contour (and therefore EPE) vary at a higher frequency than the minimum allowed fragmentation frequency. This so-called aerial image ripple problem can challenge the abilities of simple model based OPC. In addition, certain advanced RET schemes require that EPE be controlled in areas that have no adjacent mask polygon. Similarly, certain double-exposure RETs require the mutual optimization of features on multiple mask layers. Our paper will describe a flexible model based OPC scheme called Matrix OPC, which has proven capabilities of resolving these and many other advanced RET problems.

  18. Advancing Nucleosynthesis in Core-Collapse Supernovae Models Using 2D CHIMERA Simulations

    NASA Astrophysics Data System (ADS)

    Harris, J. A.; Hix, W. R.; Chertkow, M. A.; Bruenn, S. W.; Lentz, E. J.; Messer, O. B.; Mezzacappa, A.; Blondin, J. M.; Marronetti, P.; Yakunin, K.

    2014-01-01

    The deaths of massive stars as core-collapse supernovae (CCSN) serve as a crucial link in understanding galactic chemical evolution since the birth of the universe via the Big Bang. We investigate CCSN in polar axisymmetric simulations using the multidimensional radiation hydrodynamics code CHIMERA. Computational costs have traditionally constrained the evolution of the nuclear composition in CCSN models to, at best, a 14-species ?-network. However, the limited capacity of the ?-network to accurately evolve detailed composition, the neutronization and the nuclear energy generation rate has fettered the ability of prior CCSN simulations to accurately reproduce the chemical abundances and energy distributions as known from observations. These deficits can be partially ameliorated by "post-processing" with a more realistic network. Lagrangian tracer particles placed throughout the star record the temporal evolution of the initial simulation and enable the extension of the nuclear network evolution by incorporating larger systems in post-processing nucleosynthesis calculations. We present post-processing results of the four ab initio axisymmetric CCSN 2D models of Bruenn et al. (2013) evolved with the smaller ?-network, and initiated from stellar metallicity, non-rotating progenitors of mass 12, 15, 20, and 25 M? from Woosley & Heger (2007). As a test of the limitations of post-processing, we provide preliminary results from an ongoing simulation of the 15 M? model evolved with a realistic 150 species nuclear reaction network in situ. With more accurate energy generation rates and an improved determination of the thermodynamic trajectories of the tracer particles, we can better unravel the complicated multidimensional "mass-cut" in CCSN simulations and probe for less energetically significant nuclear processes like the ?p-process and the r-process, which require still larger networks.

  19. Simulation of Advanced Large-Scale HPC Architectures Simulation of Advanced Large-Scale HPC

    E-print Network

    Engelmann, Christian

    Simulation of Advanced Large-Scale HPC Architectures Simulation of Advanced Large-Scale HPC Architectures Frank Lauer 28. April 2010 Frank Lauer 1 / 1 #12;Simulation of Advanced Large-Scale HPC;Simulation of Advanced Large-Scale HPC Architectures History HPC Frank Lauer 3 / 1 #12;Simulation of Advanced

  20. A Damage Model for the Simulation of Delamination in Advanced Composites under Variable-Mode Loading

    NASA Technical Reports Server (NTRS)

    Turon, A.; Camanho, P. P.; Costa, J.; Davila, C. G.

    2006-01-01

    A thermodynamically consistent damage model is proposed for the simulation of progressive delamination in composite materials under variable-mode ratio. The model is formulated in the context of Damage Mechanics. A novel constitutive equation is developed to model the initiation and propagation of delamination. A delamination initiation criterion is proposed to assure that the formulation can account for changes in the loading mode in a thermodynamically consistent way. The formulation accounts for crack closure effects to avoid interfacial penetration of two adjacent layers after complete decohesion. The model is implemented in a finite element formulation, and the numerical predictions are compared with experimental results obtained in both composite test specimens and structural components.

  1. Advanced simulation of digital filters

    Microsoft Academic Search

    G. S. Doyle

    1980-01-01

    An Advanced Simulation of Digital Filters has been implemented on the IBM 360\\/67 computer utilizing Tektronix hardware and software. The program package is appropriate for use by persons beginning their study of digital signal processing or for filter analysis. The ASDF programs provide the user with an interactive method by which filter pole and zero locations can be manipulated. Graphical

  2. An advanced object-based software framework for complex ecosystem modeling and simulation

    SciTech Connect

    Sydelko, P. J.; Dolph, J. E.; Majerus, K. A.; Taxon, T. N.

    2000-06-29

    Military land managers and decision makers face an ever increasing challenge to balance maximum flexibility for the mission with a diverse set of multiple land use, social, political, and economic goals. In addition, these goals encompass environmental requirements for maintaining ecosystem health and sustainability over the long term. Spatiotemporal modeling and simulation in support of adaptive ecosystem management can be best accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques through a geographic information system (GIS)-based backbone. Recently, an object-oriented (OO) architectural framework was developed for IDLAMS (OO-IDLAMS). This OO-IDLAMS Prototype was built upon and leverages from the Dynamic Information Architecture System (DIAS) developed by Argonne National Laboratory. DIAS is an object-based architectural framework that affords a more integrated, dynamic, and flexible approach to comprehensive ecosystem modeling than was possible with the GIS-based integration approach of the original IDLAMS. The flexibility, dynamics, and interoperability demonstrated through this case study of an object-oriented approach have the potential to provide key technology solutions for many of the military's multiple-use goals and needs for integrated natural resource planning and ecosystem management.

  3. Advances in the simulation of toroidal gyro Landau fluid model turbulence

    SciTech Connect

    Waltz, R.E. [General Atomics, San Diego, CA (United States); Kerbel, G.D.; Milovich, J. [Lawrence Livermore National Lab., CA (United States); Hammett, G.W. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1994-12-01

    The gyro-Landau fluid (GLF) model equations for toroidal geometry have been recently applied to the study ion temperature gradient (ITG) mode turbulence using the 3D nonlinear ballooning mode representation (BMR). The present paper extends this work by treating some unresolved issues conceming ITG turbulence with adiabatic electrons. Although eddies are highly elongated in the radial direction long time radial correlation lengths are short and comparable to poloidal lengths. Although transport at vanishing shear is not particularly large, transport at reverse global shear, is significantly less. Electrostatic transport at moderate shear is not much effected by inclusion of local shear and average favorable curvature. Transport is suppressed when critical E{times}B rotational shear is comparable to the maximum linear growth rate with only a weak dependence on magnetic shear. Self consistent turbulent transport of toroidal momentum can result in a transport bifurcation at suffciently large r/(Rq). However the main thrust of the new formulation in the paper deals with advances in the development of finite beta GLF models with trapped electron and BMR numerical methods for treating the fast parallel field motion of the untrapped electrons.

  4. Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration.

    SciTech Connect

    Criscenti, Louise Jacqueline; Sassani, David Carl; Arguello, Jose Guadalupe, Jr.; Dewers, Thomas A.; Bouchard, Julie F.; Edwards, Harold Carter; Freeze, Geoffrey A.; Wang, Yifeng; Schultz, Peter Andrew

    2011-02-01

    This report describes the progress in fiscal year 2010 in developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. Waste IPSC activities in fiscal year 2010 focused on specifying a challenge problem to demonstrate proof of concept, developing a verification and validation plan, and performing an initial gap analyses to identify candidate codes and tools to support the development and integration of the Waste IPSC. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities that cannot be acquired or suitably integrated, verified, or validated. This year-end progress report documents the FY10 status of acquisition, development, and integration of thermal-hydrologic-chemical-mechanical (THCM) code capabilities, frameworks, and enabling tools and infrastructure.

  5. Advances in Supply Chain Simulation

    Microsoft Academic Search

    Agostino G. Bruzzone; Yuri Merkuryev

    2009-01-01

    The lecture aims to provide an insight into modern approaches to simulation-based analysis of supply chains. It gives an overview of using modeling and simulation (M&S) for facing different types of activities in supply chain management. In particular, different issues are considered, starting with new criticality such as: green logistics; supply chain resilience; sustainable logistics; logistics security; logistics safety; logistics

  6. Leveraging data analytics, patterning simulations and metrology models to enhance CD metrology accuracy for advanced IC nodes

    NASA Astrophysics Data System (ADS)

    Rana, Narender; Zhang, Yunlin; Kagalwala, Taher; Hu, Lin; Bailey, Todd

    2014-04-01

    Integrated Circuit (IC) technology is changing in multiple ways: 193i to EUV exposure, planar to non-planar device architecture, from single exposure lithography to multiple exposure and DSA patterning etc. Critical dimension (CD) control requirement is becoming stringent and more exhaustive: CD and process window are shrinking., three sigma CD control of < 2 nm is required in complex geometries, and metrology uncertainty of < 0.2 nm is required to achieve the target CD control for advanced IC nodes (e.g. 14 nm, 10 nm and 7 nm nodes). There are fundamental capability and accuracy limits in all the metrology techniques that are detrimental to the success of advanced IC nodes. Reference or physical CD metrology is provided by CD-AFM, and TEM while workhorse metrology is provided by CD-SEM, Scatterometry, Model Based Infrared Reflectrometry (MBIR). Precision alone is not sufficient moving forward. No single technique is sufficient to ensure the required accuracy of patterning. The accuracy of CD-AFM is ~1 nm and precision in TEM is poor due to limited statistics. CD-SEM, scatterometry and MBIR need to be calibrated by reference measurements for ensuring the accuracy of patterned CDs and patterning models. There is a dire need of measurement with < 0.5 nm accuracy and the industry currently does not have that capability with inline measurments. Being aware of the capability gaps for various metrology techniques, we have employed data processing techniques and predictive data analytics, along with patterning simulation and metrology models, and data integration techniques to selected applications demonstrating the potential solution and practicality of such an approach to enhance CD metrology accuracy. Data from multiple metrology techniques has been analyzed in multiple ways to extract information with associated uncertainties and integrated to extract the useful and more accurate CD and profile information of the structures. This paper presents the optimization of scatterometry and MBIR model calibration and feasibility to extrapolate not only in design and process space but from one process step to a previous process step. Well calibrated scatterometry model or patterning simulation model can be used to accurately extrapolate and interpolate in the design and process space for lithography patterning where AFM is not capable to accurately measure sub-40 nm trenches. Uncertainty associated with extrapolation can be large and needs to be minimized. We have made use of measurements from CD-SEM and CD-AFM, along with the patterning and scatterometry simulation models to estimate the uncertainty associated with extrapolation and methods to reduce it. First time we have reported the application of machine learning (Artificial Neural Networks) to the resist shrinkage systematic phenomenon to accurately predict the preshrink CD based on supervised learning using the CD-AFM data. The study lays out various basic concepts, approaches and protocols of multiple source data processing and integration for hybrid metrology approach. Impacts of this study include more accurate metrology, patterning models and better process controls for advanced IC nodes.

  7. Advanced simulation of digital filters

    NASA Astrophysics Data System (ADS)

    Doyle, G. S.

    1980-09-01

    An Advanced Simulation of Digital Filters has been implemented on the IBM 360/67 computer utilizing Tektronix hardware and software. The program package is appropriate for use by persons beginning their study of digital signal processing or for filter analysis. The ASDF programs provide the user with an interactive method by which filter pole and zero locations can be manipulated. Graphical output on both the Tektronix graphics screen and the Versatec plotter are provided to observe the effects of pole-zero movement.

  8. Advanced Stochastic Modeling and Simulation (SE/ME714) Spring 2011

    E-print Network

    techniques TEXTBOOKS · Stochastic Processes, 2nd Edition, Sheldon Ross, Wiley, 1996. · Simulation, 3rd Edition, Sheldon Ross, Academic Press, 2002. GRADING Homework: 30%, Exams (and/or projects) 60%, class

  9. ADVANCED URBANIZED METEOROLOGICAL MODELING AND AIR QUALITY SIMULATIONS WITH CMAQ AT NEIGHBORHOOD SCALES

    EPA Science Inventory

    We present results from a study testing the new boundary layer parameterization method, the canopy drag approach (DA) which is designed to explicitly simulate the effects of buildings, street and tree canopies on the dynamic, thermodynamic structure and dispersion fields in urban...

  10. Software Framework for Advanced Power Plant Simulations

    SciTech Connect

    John Widmann; Sorin Munteanu; Aseem Jain; Pankaj Gupta; Mark Moales; Erik Ferguson; Lewis Collins; David Sloan; Woodrow Fiveland; Yi-dong Lang; Larry Biegler; Michael Locke; Simon Lingard; Jay Yun

    2010-08-01

    This report summarizes the work accomplished during the Phase II development effort of the Advanced Process Engineering Co-Simulator (APECS). The objective of the project is to develop the tools to efficiently combine high-fidelity computational fluid dynamics (CFD) models with process modeling software. During the course of the project, a robust integration controller was developed that can be used in any CAPE-OPEN compliant process modeling environment. The controller mediates the exchange of information between the process modeling software and the CFD software. Several approaches to reducing the time disparity between CFD simulations and process modeling have been investigated and implemented. These include enabling the CFD models to be run on a remote cluster and enabling multiple CFD models to be run simultaneously. Furthermore, computationally fast reduced-order models (ROMs) have been developed that can be 'trained' using the results from CFD simulations and then used directly within flowsheets. Unit operation models (both CFD and ROMs) can be uploaded to a model database and shared between multiple users.

  11. Advanced Stochastic Modeling and Simulation (SE/ME714) (Discrete Stochastic Processes)

    E-print Network

    and modeling approaches used in many areas of science & engineering as well as the theory used for the analysis of the models. Instructor: Pirooz Vakili Division of Systems Engineering & Mechanical Engineering Department 15 (d) Applications 2. Renewal theory (a basic theoretical tool for analysis) (a) Convergence of random

  12. Advanced Stochastic Modeling and Simulation (SE/ME714) (Discrete Stochastic Processes)

    E-print Network

    Lin, Xi

    and modeling approaches used in many areas of science & engineering as well as the theory used for the analysis of the models. Instructor: Pirooz Vakili Division of Systems Engineering & Mechanical Engineering Department 15 (a basic theoretical tool for analysis) (a) Convergence of random sequences (a review) (b) Renewal

  13. Lightweighting Automotive Materials for Increased Fuel Efficiency and Delivering Advanced Modeling and Simulation Capabilities to U.S. Manufacturers

    SciTech Connect

    Hale, Steve

    2013-09-11

    Abstract The National Center for Manufacturing Sciences (NCMS) worked with the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), to bring together research and development (R&D) collaborations to develop and accelerate the knowledgebase and infrastructure for lightweighting materials and manufacturing processes for their use in structural and applications in the automotive sector. The purpose/importance of this DOE program: • 2016 CAFÉ standards. • Automotive industry technology that shall adopt the insertion of lightweighting material concepts towards manufacturing of production vehicles. • Development and manufacture of advanced research tools for modeling and simulation (M&S) applications to reduce manufacturing and material costs. • U.S. competitiveness that will help drive the development and manufacture of the next generation of materials. NCMS established a focused portfolio of applied R&D projects utilizing lightweighting materials for manufacture into automotive structures and components. Areas that were targeted in this program: • Functionality of new lightweighting materials to meet present safety requirements. • Manufacturability using new lightweighting materials. • Cost reduction for the development and use of new lightweighting materials. The automotive industry’s future continuously evolves through innovation, and lightweight materials are key in achieving a new era of lighter, more efficient vehicles. Lightweight materials are among the technical advances needed to achieve fuel/energy efficiency and reduce carbon dioxide (CO2) emissions: • Establish design criteria methodology to identify the best materials for lightweighting. • Employ state-of-the-art design tools for optimum material development for their specific applications. • Match new manufacturing technology to production volume. • Address new process variability with new production-ready processes.

  14. Advanced geometric techniques in 3D process simulation

    Microsoft Academic Search

    N. A. Golias; R. W. Dutton

    1996-01-01

    The modeling of semiconductor devices in the deep submicron era is a complicated and challenging procedure. Due to continuous scaling of IC structures many physical effects pose requirements for a full 3D simulation. The incorporation of advanced computational geometry techniques is imperative in the realization of such 3D process simulation tools. The simulation of a virtual factory, with the various

  15. Modeling, Simulation and Analysis of Complex Networked Systems: A Program Plan for DOE Office of Advanced Scientific Computing Research

    SciTech Connect

    Brown, D L

    2009-05-01

    Many complex systems of importance to the U.S. Department of Energy consist of networks of discrete components. Examples are cyber networks, such as the internet and local area networks over which nearly all DOE scientific, technical and administrative data must travel, the electric power grid, social networks whose behavior can drive energy demand, and biological networks such as genetic regulatory networks and metabolic networks. In spite of the importance of these complex networked systems to all aspects of DOE's operations, the scientific basis for understanding these systems lags seriously behind the strong foundations that exist for the 'physically-based' systems usually associated with DOE research programs that focus on such areas as climate modeling, fusion energy, high-energy and nuclear physics, nano-science, combustion, and astrophysics. DOE has a clear opportunity to develop a similarly strong scientific basis for understanding the structure and dynamics of networked systems by supporting a strong basic research program in this area. Such knowledge will provide a broad basis for, e.g., understanding and quantifying the efficacy of new security approaches for computer networks, improving the design of computer or communication networks to be more robust against failures or attacks, detecting potential catastrophic failure on the power grid and preventing or mitigating its effects, understanding how populations will respond to the availability of new energy sources or changes in energy policy, and detecting subtle vulnerabilities in large software systems to intentional attack. This white paper outlines plans for an aggressive new research program designed to accelerate the advancement of the scientific basis for complex networked systems of importance to the DOE. It will focus principally on four research areas: (1) understanding network structure, (2) understanding network dynamics, (3) predictive modeling and simulation for complex networked systems, and (4) design, situational awareness and control of complex networks. The program elements consist of a group of Complex Networked Systems Research Institutes (CNSRI), tightly coupled to an associated individual-investigator-based Complex Networked Systems Basic Research (CNSBR) program. The CNSRI's will be principally located at the DOE National Laboratories and are responsible for identifying research priorities, developing and maintaining a networked systems modeling and simulation software infrastructure, operating summer schools, workshops and conferences and coordinating with the CNSBR individual investigators. The CNSBR individual investigator projects will focus on specific challenges for networked systems. Relevancy of CNSBR research to DOE needs will be assured through the strong coupling provided between the CNSBR grants and the CNSRI's.

  16. Advanced friction modeling for sheet metal forming

    Microsoft Academic Search

    J. Hol; M. V. Cid Alfaro; M. B. de Rooij; T. Meinders

    2011-01-01

    The Coulomb friction model is frequently used for sheet metal forming simulations. This model incorporates a constant coefficient of friction and does not take the influence of important parameters such as contact pressure or deformation of the sheet material into account. This article presents a more advanced friction model for large-scale forming simulations based on the surface changes on the

  17. Simulator design for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerald R.

    1992-01-01

    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  18. Improved Low-cloud Simulation from the Community Atmosphere Model with an Advanced Third-order Turbulence Closure

    NASA Astrophysics Data System (ADS)

    Cheng, A.; Xu, K.

    2013-12-01

    This presentation describes the implementation and testing of an advanced third-order turbulence closure, an intermediately-prognostic higher-order turbulence closure (IPHOC), into the Community Atmosphere Model version 5 (CAM5). The third-order turbulence closure introduces a joint double-Gaussian distribution of liquid water potential temperature, total water mixing ratio, and vertical velocity to represent the subgrid scale variations including skewed turbulence circulations. The distribution is inferred from the first-, second-, and third-order moments of the variables given above and is used to diagnose cloud fraction and grid-mean liquid water mixing ratio, as well as the buoyancy term and fourth-order terms in the equations describing the evolution of the second- and third-order moments. In addition, a diagnostic planetary boundary layer (PBL) height approach has been incorporated in IPHOC in order to resolve the strong inversion above PBL for the coarse general circulation model (GCM) vertical grid-spacing. The IPHOC replaces PBL, shallow convection, and cloud macrophysics parameterizations in CAM5. The coupling of CAM5 with IPHOC (CAM5-IP) represents a more unified treatment of boundary layer and shallow convective processes. Results from global climate simulations are presented and suggest that CAM5-IP can provide a better treatment of boundary layer clouds and processes when compared to CAM5. The global annual mean low cloud fraction and precipitation are compared among CAM5, CAM5-IP, and a multi-scale modeling framework model with IPHOC (MMF-IP). The low cloud amounts near the west coast of the subtropical continents are well produced in CAM5-IP and are more abundant than in other two models. The global mean liquid water path is the closest to the SSM/I observation. The cloud structures from CAM5-IP, represented by the cloud fraction and cloud water content at 15°S transect, compare well with the CloudSat/CALIPSO observations. The shallow cumulus clouds from the standard CAM5 are shallower and have less liquid, while those from MMF-IP are deeper and have more liquid than from the CloudSat/CALIPSO observations. Interpretations of these results will be provided at the meeting.

  19. Advanced WCDMA radio network simulator

    Microsoft Academic Search

    H. Holma

    1999-01-01

    ABSTRACT If only good coverage is required in GSM networks, high frequency reuse factors can be used. In that case the network capacity is directly determined by the number,of available time slots, and no advanced radio control algorithms are needed. If high capacity is required and fractional loading is used in GSM networks, advanced radio resource management ,algorithms ,are required.

  20. ADVANCED CHEMISTRY BASINS MODEL

    SciTech Connect

    William Goddard III; Lawrence Cathles III; Mario Blanco; Paul Manhardt; Peter Meulbroek; Yongchun Tang

    2004-05-01

    The advanced Chemistry Basin Model project has been operative for 48 months. During this period, about half the project tasks are on projected schedule. On average the project is somewhat behind schedule (90%). Unanticipated issues are causing model integration to take longer then scheduled, delaying final debugging and manual development. It is anticipated that a short extension will be required to fulfill all contract obligations.

  1. Physical modelling and advanced simulations of gas–liquid two-phasejet flows in atomization and sprays

    Microsoft Academic Search

    X. Jiang; G. A. Siamas; K. Jagus; T. G. Karayiannis

    2010-01-01

    This review attempts to summarize the physical models and advanced\\u000d\\u000a\\u0009methods used in computational studies of gas–liquid two-phase jet\\u000d\\u000a\\u0009flows encountered in atomization and spray processes. In traditional\\u000d\\u000a\\u0009computational fluid dynamics (CFD) based on Reynolds-averaged Navier–Stokes\\u000d\\u000a\\u0009(RANS) approach, physical modelling of atomization and sprays is\\u000d\\u000a\\u0009an essential part of the two-phase flow computation. In more advanced\\u000d\\u000a\\u0009CFD such as direct

  2. An advanced dispatch simulator with advanced dispatch algorithm

    SciTech Connect

    Kafka, R.J. (Potomac Electric Power Co., Washington, DC (USA)); Fink, L.H. (Carlsen and Fink Associates, Inc., Fairfax, VA (USA)); Balu, N.J. (Electric Power Research Inst., Palo Alto, CA (USA)); Crim, H.G. (Potomac Electric Power Co., Upper Marlboro, MD (USA))

    1989-01-01

    This paper reports on an interactive automatic generation control (AGC) simulator. Improved and timely information regarding fossil fired plant performance is potentially useful in the economic dispatch of system generating units. Commonly used economic dispatch algorithms are not able to take full advantage of this information. The dispatch simulator was developed to test and compare economic dispatch algorithms which might be able to show improvement over standard economic dispatch algorithms if accurate unit information were available. This dispatch simulator offers substantial improvements over previously available simulators. In addition, it contains an advanced dispatch algorithm which shows control and performance advantages over traditional dispatch algorithms for both plants and electric systems.

  3. Simulation of the effects of limited water on photosynthesis and transpiration in field crops: Can we advance our modeling approaches?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biggest challenge to simulation models of agricultural crops is the accurate quantification of the physiological responses of crop growth and development to non-optimal changes in its physical and chemical environment. A large body of research has addressed knowledge gaps in our understanding of...

  4. An advanced fuel cell simulator 

    E-print Network

    Acharya, Prabha Ramchandra

    2005-11-01

    subsystems such as converters and inverters. This thesis proposes a low-cost and an easy-to-use fuel cell simulator using a programmable DC supply along with a control module written in LabVIEW. This simulator reproduces the electrical characteristics of a 5...

  5. Simulation methods for advanced scientific computing

    Microsoft Academic Search

    T. E. Booth; J. A. Carlson; R. A. Forster

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to create effective new algorithms for solving N-body problems by computer simulation. The authors concentrated on developing advanced classical and quantum Monte Carlo techniques. For simulations of phase transitions in classical systems,

  6. SBRAS — an advanced simulator of spaceborne radar

    Microsoft Academic Search

    Min Wang; Diannong Liang; Haifeng Huang; Zhen Dong

    2007-01-01

    An application-oriented spaceborne radar advanced simulator (SBRAS) is presented in this paper. SBRAS is initiated by the technical and economical requirements to verify formation-flying distributed satellites synthetic aperture radar (SAR) scheme and simplify the instrument hardware design. The simulator develops a full flow of signal processing including formation design, SAR raw data simulation of nature scene, imaging, InSAR processing, digital

  7. Advances in large eddy simulation methodology for complex flows

    Microsoft Academic Search

    Parviz Moin

    2002-01-01

    A review is provided of the recent advances in the derivation of the constitutive equations for large eddy simulation, subgrid scale modeling, wall modeling and applications of LES to turbulent combustion. The majority of the paper focuses on a review of two numerical methods for LES in complex geometry: the immersed boundary method and an unstructured mesh scheme. The latter

  8. Development of advanced materials for spallation neutron sources and radiation damage simulation based on multi-scale models

    NASA Astrophysics Data System (ADS)

    Kawai, Masayoshi; Kurishita, Hiroaki; Kokawa, Hiroyuki; Watanabe, Seiichi; Sakaguchi, Norihito; Kikuchi, Kenji; Saito, Shigeru; Yoshiie, Toshimasa; Iwase, Hiroshi; Ito, Takahiro; Hashimoto, Satoshi; Kaneko, Yoshihisa; Futakawa, Masatoshi; Ishino, Shiori; JSPS Grant Team

    2012-12-01

    This report describes the status review of the JSPS Grant Team to develop advanced materials for the spallation neutron sources and modeling of radiation damage. One of the advanced materials is a toughness enhanced, fine-grained tungsten material (W-TiC) having four-times larger fracture toughness than ordinary tungsten and appreciable RT ductility in the recrystallized state. The other is an intergranular crack (IGC)-resistant austenitic stainless steel which was processed by the grain-boundary engineering (GBE). The experimental results are devoted to corrosion in a lead-bismuth eutectic, arrest of corrosion of weld-decay, radiation damage and creep rupture as well as new technique of GBE using a laser and annealing procedure. New technique seems to be applicable to large or complicated-shaped components. A series of the multi-scale models is built up from nuclear reaction between incident particles and medium nuclei to material property change due to radiation damage. Sample calculation is made on 3 mm-thick nickel bombarded by 3 GeV protons.

  9. New scene projector developments at the AMRDEC's advanced simulation center

    NASA Astrophysics Data System (ADS)

    Saylor, Daniel A.; Bowden, Mark; Buford, James

    2006-05-01

    The Aviation and Missile Research, Engineering, and Development Center's (AMRDEC) System Simulation and Development Directorate (SS&DD) has an extensive history of applying all types of modeling and simulation (M&S) to weapon system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation and test for many years. Key to the successful application of HWIL testing at AMRDEC has been the use of state-of-the-art Scene Projector technologies. This paper describes recent advancements over the past year within the AMRDEC Advanced Simulation Center (ASC) HWIL facilities with a specific emphasis on the state of the various IRSP technologies employed. Areas discussed include application of FMS-compatible IR projectors, advancements in hybrid and multi-spectral projectors, and characterization of existing and emerging technologies.

  10. Simulation model of the F/A-18 high angle-of-attack research vehicle utilized for the design of advanced control laws

    NASA Technical Reports Server (NTRS)

    Strickland, Mark E.; Bundick, W. Thomas; Messina, Michael D.; Hoffler, Keith D.; Carzoo, Susan W.; Yeager, Jessie C.; Beissner, Fred L., Jr.

    1996-01-01

    The 'f18harv' six degree-of-freedom nonlinear batch simulation used to support research in advanced control laws and flight dynamics issues as part of NASA's High Alpha Technology Program is described in this report. This simulation models an F/A-18 airplane modified to incorporate a multi-axis thrust-vectoring system for augmented pitch and yaw control power and actuated forebody strakes for enhanced aerodynamic yaw control power. The modified configuration is known as the High Alpha Research Vehicle (HARV). The 'f18harv' simulation was an outgrowth of the 'f18bas' simulation which modeled the basic F/A-18 with a preliminary version of a thrust-vectoring system designed for the HARV. The preliminary version consisted of two thrust-vectoring vanes per engine nozzle compared with the three vanes per engine actually employed on the F/A-18 HARV. The modeled flight envelope is extensive in that the aerodynamic database covers an angle-of-attack range of -10 degrees to +90 degrees, sideslip range of -20 degrees to +20 degrees, a Mach Number range between 0.0 and 2.0, and an altitude range between 0 and 60,000 feet.

  11. Parallel methods for the flight simulation model

    Microsoft Academic Search

    Wei Zhong Xiong; C. Swietlik

    1994-01-01

    The Advanced Computer Applications Center (ACAC) has been involved in evaluating advanced parallel architecture computers and the applicability of these machines to computer simulation models. The advanced systems investigated include parallel machines with shared. memory and distributed architectures consisting of an eight processor Alliant FX\\/8, a twenty four processor sor Sequent Symmetry, Cray XMP, IBM RISC 6000 model 550, and

  12. Two-surface plasticity Model and Its Application to Spring-back Simulation of Automotive Advanced High Strength Steel Sheets

    NASA Astrophysics Data System (ADS)

    Park, Taejoon; Seok, Dong-Yoon; Lee, Chul-Hwan; Noma, Nobuyasu; Kuwabara, Toshihiko; Stoughton, Thomas B.; Chung, Kwansoo

    2011-08-01

    A two-surface isotropic-kinematic hardening law was developed based on a two-surface plasticity model previously proposed by Lee et al., (2007, Int. J. Plast. 23, 1189-1212). In order to properly represent the Bauschinger and transient behaviors as well as permanent softening during reverse loading with various pre-strains, both the inner yield surface and the outer bounding surface expand (isotropic hardening) and translate (kinematic hardening) in this two-surface model. As for the permanent softening, both the isotropic hardening and the kinematic hardening evolution of the outer bounding surface were modified by introducing softening parameters. The numerical formulation was also developed based on the incremental plasticity theory and the developed constitutive law was implemented into the commercial finite element program, ABAQUS/Explicit and ABAQUS/Standard using the user-defined material subroutines. In this work, a dual phase (DP) steel was considered as an advanced high strength steel sheet and uni-axial tension tests and uni-axial tension-compression-tension tests were performed for the characterization of the material property. For a validation purpose, the developed two-surface plasticity model was applied to the 2-D draw bending test proposed as a benchmark problem of the NUMISHEET 2011 conference and successfully validated with experiments.

  13. Advanced Chemistry Basins Model

    SciTech Connect

    William Goddard; Mario Blanco; Lawrence Cathles; Paul Manhardt; Peter Meulbroek; Yongchun Tang

    2002-11-10

    The DOE-funded Advanced Chemistry Basin model project is intended to develop a public domain, user-friendly basin modeling software under PC or low end workstation environment that predicts hydrocarbon generation, expulsion, migration and chemistry. The main features of the software are that it will: (1) afford users the most flexible way to choose or enter kinetic parameters for different maturity indicators; (2) afford users the most flexible way to choose or enter compositional kinetic parameters to predict hydrocarbon composition (e.g., gas/oil ratio (GOR), wax content, API gravity, etc.) at different kerogen maturities; (3) calculate the chemistry, fluxes and physical properties of all hydrocarbon phases (gas, liquid and solid) along the primary and secondary migration pathways of the basin and predict the location and intensity of phase fractionation, mixing, gas washing, etc.; and (4) predict the location and intensity of de-asphaltene processes. The project has be operative for 36 months, and is on schedule for a successful completion at the end of FY 2003.

  14. Models, Traffic Models, Simulation, and Traffic Simulation

    Microsoft Academic Search

    Jaume Barceló

    \\u000a This introductory chapter to a book on traffic simulation fundamentals is aimed at setting up a comprehensive framework for\\u000a simulation as a well-established and grounded OR technique and its specificities when applied to traffic systems; the main\\u000a approaches to traffic simulation and the principles of traffic simulation model building; the fundamentals of traffic flow\\u000a theory and its application to traffic

  15. Computational Models of Human Performance: Validation of Memory and Procedural Representation in Advanced Air/Ground Simulation

    NASA Technical Reports Server (NTRS)

    Corker, Kevin M.; Labacqz, J. Victor (Technical Monitor)

    1997-01-01

    The Man-Machine Interaction Design and Analysis System (MIDAS) under joint U.S. Army and NASA cooperative is intended to assist designers of complex human/automation systems in successfully incorporating human performance capabilities and limitations into decision and action support systems. MIDAS is a computational representation of multiple human operators, selected perceptual, cognitive, and physical functions of those operators, and the physical/functional representation of the equipment with which they operate. MIDAS has been used as an integrated predictive framework for the investigation of human/machine systems, particularly in situations with high demands on the operators. We have extended the human performance models to include representation of both human operators and intelligent aiding systems in flight management, and air traffic service. The focus of this development is to predict human performance in response to aiding system developed to identify aircraft conflict and to assist in the shared authority for resolution. The demands of this application requires representation of many intelligent agents sharing world-models, coordinating action/intention, and cooperative scheduling of goals and action in an somewhat unpredictable world of operations. In recent applications to airborne systems development, MIDAS has demonstrated an ability to predict flight crew decision-making and procedural behavior when interacting with automated flight management systems and Air Traffic Control. In this paper, we describe two enhancements to MIDAS. The first involves the addition of working memory in the form of an articulatory buffer for verbal communication protocols and a visuo-spatial buffer for communications via digital datalink. The second enhancement is a representation of multiple operators working as a team. This enhanced model was used to predict the performance of human flight crews and their level of compliance with commercial aviation communication procedures. We show how the data produced by MIDAS compares with flight crew performance data from full mission simulations. Finally, we discuss the use of these features to study communication issues connected with aircraft-based separation assurance.

  16. Advances in the Modelling of Motorcycle Dynamics

    Microsoft Academic Search

    R. S. Sharp; S. Evangelou; D. J. N. Limebeer

    2004-01-01

    Starting from an existing advanced motorcycle dynamics model, which allows simulation of reasonably general motions and stability, modal and response computations for small perturbations from any trim condition, improvements are described. These concern (a) tyre\\/road contact geometry, (b) tyre shear force and moment descriptions, as functions of load, slip and camber, (c) tyre relaxation properties, (d) a new analytic treatment

  17. Advanced ST Plasma Scenario Simulations for NSTX

    SciTech Connect

    C.E. Kessel; E.J. Synakowski; D.A. Gates; R.W. Harvey; S.M. Kaye; T.K. Mau; J. Menard; C.K. Phillips; G. Taylor; R. Wilson; the NSTX Research Team

    2004-10-28

    Integrated scenario simulations are done for NSTX [National Spherical Torus Experiment] that address four primary milestones for developing advanced ST configurations: high {beta} and high {beta}{sub N} inductive discharges to study all aspects of ST physics in the high-beta regime; non-inductively sustained discharges for flattop times greater than the skin time to study the various current-drive techniques; non-inductively sustained discharges at high {beta} for flattop times much greater than a skin time which provides the integrated advanced ST target for NSTX; and non-solenoidal start-up and plasma current ramp-up. The simulations done here use the Tokamak Simulation Code (TSC) and are based on a discharge 109070. TRANSP analysis of the discharge provided the thermal diffusivities for electrons and ions, the neutral-beam (NB) deposition profile, and other characteristics. CURRAY is used to calculate the High Harmonic Fast Wave (HHFW) heating depositions and current drive. GENRAY/CQL3D is used to establish the heating and CD [current drive] deposition profiles for electron Bernstein waves (EBW). Analysis of the ideal-MHD stability is done with JSOLVER, BALMSC, and PEST2. The simulations indicate that the integrated advanced ST plasma is reachable, obtaining stable plasmas with {beta} {approx} 40% at {beta}{sub N}'s of 7.7-9, I{sub P} = 1.0 MA, and B{sub T} = 0.35 T. The plasma is 100% non-inductive and has a flattop of 4 skin times. The resulting global energy confinement corresponds to a multiplier of H{sub 98(y,2)} = 1.5. The simulations have demonstrated the importance of HHFW heating and CD, EBW off-axis CD, strong plasma shaping, density control, and early heating/H-mode transition for producing and optimizing these plasma configurations.

  18. Advanced ST plasma scenario simulations for NSTX

    NASA Astrophysics Data System (ADS)

    Kessel, C. E.; Synakowski, E. J.; Bell, M. E.; Gates, D. A.; Harvey, R. W.; Kaye, S. M.; Mau, T. K.; Menard, J.; Phillips, C. K.; Taylor, G.; Wilson, R.; NSTX Research Team

    2005-08-01

    Integrated scenario simulations are done for NSTX that address four primary objectives for developing advanced spherical torus (ST) configurations: high ? and high ?N inductive discharges to study all aspects of ST physics in the high ? regime; non-inductively sustained discharges for flattop times greater than the skin time to study the various current drive techniques; non-inductively sustained discharges at high ? for flattop times much greater than a skin time which provides the integrated advanced ST target for NSTX and non-solenoidal startup and plasma current rampup. The simulations done here use the tokamak simulation code and are based on a discharge 109070. TRANSP analysis of the discharge provided the thermal diffusivities for electrons and ions, the neutral beam deposition profile and other characteristics. CURRAY is used to calculate the high harmonic fast wave (HHFW) heating depositions and current drive. GENRAY/CQL3D is used to establish the heating and CD deposition profiles for electron Bernstein waves (EBW). Analysis of the ideal MHD stability is done with JSOLVER, BALMSC and PEST2. The simulations indicate that the integrated advanced ST plasma is reachable, obtaining stable plasmas with ?T ap 40% at ?N's of 7.7-9, IP = 1.0 MA and BT = 0.35 T. The plasma is 100% non-inductive and has a flattop of four skin times. The resulting global energy confinement corresponds to a multiplier of H98(y),2 = 1.5. The simulations have demonstrated the importance of HHFW heating and CD, EBW off-axis CD, strong plasma shaping, density control and early heating/H-mode transition for producing and optimizing these plasma configurations.

  19. The Advanced Regional Prediction System (ARPS) – A multi-scale nonhydrostatic atmospheric simulation and prediction model. Part I: Model dynamics and verification

    Microsoft Academic Search

    M. Xue; K. K. Droegemeier; V. Wong

    2000-01-01

    Summary  ?A completely new nonhydrostatic model system known as the Advanced Regional Prediction System (ARPS) has been developed in\\u000a recent years at the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma. The ARPS is designed\\u000a from the beginning to serve as an effective tool for basic and applied research and as a system suitable for explicit

  20. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect

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

    2009-01-20

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

  1. Recent advances in conductivity and EOS modeling for high energy density physics simulations near the metal-insulator transition

    Microsoft Academic Search

    M. P. Desjarlais; S. E. Rosenthal; K. Cochrane

    2001-01-01

    Summary form only given. Many present day high energy density physics experiments, such as wire-array Z pinches, imploding liners, and exploding wires, evolve through complex conductivity and equation of state regimes, starting from solid density and rapidly transitioning through liquid and vapor to plasma. Of particular importance for the accurate computer simulation of the early time evolution of these experiments

  2. The Role of Aircraft Noise Simulation Models

    Microsoft Academic Search

    Kenneth J. Plotkin

    Noise simulation models, which compute detailed time histories of noise at a given point, have usually been considered to be specialized research tools. There are, however, situations where the detail provided by simulation can be important, and advances in computing power have made simulation practical for a wider range of problems than in the past. This paper describes the structure

  3. Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC) : gap analysis for high fidelity and performance assessment code development.

    SciTech Connect

    Lee, Joon H.; Siegel, Malcolm Dean; Arguello, Jose Guadalupe, Jr.; Webb, Stephen Walter; Dewers, Thomas A.; Mariner, Paul E.; Edwards, Harold Carter; Fuller, Timothy J.; Freeze, Geoffrey A.; Jove-Colon, Carlos F.; Wang, Yifeng

    2011-03-01

    This report describes a gap analysis performed in the process of developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with rigorous verification, validation, and software quality requirements. The gap analyses documented in this report were are performed during an initial gap analysis to identify candidate codes and tools to support the development and integration of the Waste IPSC, and during follow-on activities that delved into more detailed assessments of the various codes that were acquired, studied, and tested. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities that cannot be acquired or suitably integrated, verified, or validated. The gap analysis indicates that significant capabilities may already exist in the existing THC codes although there is no single code able to fully account for all physical and chemical processes involved in a waste disposal system. Large gaps exist in modeling chemical processes and their couplings with other processes. The coupling of chemical processes with flow transport and mechanical deformation remains challenging. The data for extreme environments (e.g., for elevated temperature and high ionic strength media) that are needed for repository modeling are severely lacking. In addition, most of existing reactive transport codes were developed for non-radioactive contaminants, and they need to be adapted to account for radionuclide decay and in-growth. The accessibility to the source codes is generally limited. Because the problems of interest for the Waste IPSC are likely to result in relatively large computational models, a compact memory-usage footprint and a fast/robust solution procedure will be needed. A robust massively parallel processing (MPP) capability will also be required to provide reasonable turnaround times on the analyses that will be performed with the code. A performance assessment (PA) calculation for a waste disposal system generally requires a large number (hundreds to thousands) of model simulations to quantify the effect of model parameter uncertainties on the predicted repository performance. A set of codes for a PA calculation must be sufficiently robust and fast in terms of code execution. A PA system as a whole must be able to provide multiple alternative models for a specific set of physical/chemical processes, so that the users can choose various levels of modeling complexity based on their modeling needs. This requires PA codes, preferably, to be highly modularized. Most of the existing codes have difficulties meeting these requirements. Based on the gap analysis results, we have made the following recommendations for the code selection and code development for the NEAMS waste IPSC: (1) build fully coupled high-fidelity THCMBR codes using the existing SIERRA codes (e.g., ARIA and ADAGIO) and platform, (2) use DAKOTA to build an enhanced performance assessment system (EPAS), and build a modular code architecture and key code modules for performance assessments. The key chemical calculation modules will be built by expanding the existing CANTERA capabilities as well as by extracting useful components from other existing codes.

  4. Advances in Simulation of Wave Interaction with Extended MHD Phenomena

    SciTech Connect

    Batchelor, Donald B [ORNL; Abla, Gheni [ORNL; D'Azevedo, Ed F [ORNL; Bateman, Glenn [Lehigh University, Bethlehem, PA; Bernholdt, David E [ORNL; Berry, Lee A [ORNL; Bonoli, P. [Massachusetts Institute of Technology (MIT); Bramley, R [Indiana University; Breslau, Joshua [ORNL; Chance, M. [Princeton Plasma Physics Laboratory (PPPL); Chen, J. [Princeton Plasma Physics Laboratory (PPPL); Choi, M. [General Atomics; Elwasif, Wael R [ORNL; Foley, S. [Indiana University; Fu, GuoYong [Princeton Plasma Physics Laboratory (PPPL); Harvey, R. W. [CompX, Del Mar, CA; Jaeger, Erwin Frederick [ORNL; Jardin, S. C. [Princeton Plasma Physics Laboratory (PPPL); Jenkins, T [University of Wisconsin; Keyes, David E [Columbia University; Klasky, Scott A [ORNL; Kruger, Scott [Tech-X Corporation; Ku, Long-Poe [Princeton Plasma Physics Laboratory (PPPL); Lynch, Vickie E [ORNL; McCune, Douglas [Princeton Plasma Physics Laboratory (PPPL); Ramos, J. [Massachusetts Institute of Technology (MIT); Schissel, D. [General Atomics; Schnack, [University of Wisconsin; Wright, J. [Massachusetts Institute of Technology (MIT)

    2009-01-01

    The Integrated Plasma Simulator (IPS) provides a framework within which some of the most advanced, massively-parallel fusion modeling codes can be interoperated to provide a detailed picture of the multi-physics processes involved in fusion experiments. The presentation will cover four topics: 1) recent improvements to the IPS, 2) application of the IPS for very high resolution simulations of ITER scenarios, 3) studies of resistive and ideal MHD stability in tokamk discharges using IPS facilities, and 4) the application of RF power in the electron cyclotron range of frequencies to control slowly growing MHD modes in tokamaks and initial evaluations of optimized location for RF power deposition.

  5. Advances in Simulation of Wave Interactions with Extended MHD Phenomena

    SciTech Connect

    Batchelor, Donald B [ORNL] [ORNL; D'Azevedo, Eduardo [ORNL] [ORNL; Bateman, Glenn [ORNL] [ORNL; Bernholdt, David E [ORNL] [ORNL; Bonoli, P. [Massachusetts Institute of Technology (MIT)] [Massachusetts Institute of Technology (MIT); Bramley, Randall B [ORNL] [ORNL; Breslau, Joshua [ORNL] [ORNL; Elwasif, Wael R [ORNL] [ORNL; Foley, S. [Indiana University] [Indiana University; Jaeger, Erwin Frederick [ORNL] [ORNL; Jardin, S. C. [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Klasky, Scott A [ORNL] [ORNL; Kruger, Scott E [ORNL] [ORNL; Ku, Long-Poe [ORNL] [ORNL; McCune, Douglas [Princeton Plasma Physics Laboratory (PPPL)] [Princeton Plasma Physics Laboratory (PPPL); Ramos, J. [Massachusetts Institute of Technology (MIT)] [Massachusetts Institute of Technology (MIT); Schissel, David P [ORNL] [ORNL; Schnack, Dalton D [ORNL] [ORNL

    2009-01-01

    The Integrated Plasma Simulator (IPS) provides a framework within which some of the most advanced, massively-parallel fusion modeling codes can be interoperated to provide a detailed picture of the multi-physics processes involved in fusion experiments. The presentation will cover four topics: (1) recent improvements to the IPS, (2) application of the IPS for very high resolution simulations of ITER scenarios, (3) studies of resistive and ideal MHD stability in tokamak discharges using IPS facilities, and (4) the application of RF power in the electron cyclotron range of frequencies to control slowly growing MHD modes in tokamaks and initial evaluations of optimized location for RF power deposition.

  6. Abstract Designers of advanced power converters may choose from a variety of switching device models for simulation. Some

    E-print Network

    Kimball, Jonathan W.

    vector modulation, or direct torque control. The model can also be used for certain switched reluctance motor drives in which the modulation scheme changes for different portions of the cycle. II. IGBT

  7. Advanced integrated battery testing and simulation

    Microsoft Academic Search

    Bor Yann Liaw; Keith P Bethune; Xiao Guang Yang

    2002-01-01

    The recent rapid expansion in the use of portable electronics, computers, personal data assistants, cellular phones, power tools, and even electric and hybrid vehicles creates a strong demand on fast deployment of battery technologies at an unprecedented rate. To facilitate such a development integrated battery testing and simulation (IBTS) using computer modeling is an effective tool to improve our capability

  8. Interactive visualization to advance earthquake simulation

    USGS Publications Warehouse

    Kellogg, L.H.; Bawden, G.W.; Bernardin, T.; Billen, M.; Cowgill, E.; Hamann, B.; Jadamec, M.; Kreylos, O.; Staadt, O.; Sumner, D.

    2008-01-01

    The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth's surface and interior. Virtual mapping tools allow virtual "field studies" in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method's strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations. ?? Birkhaueser 2008.

  9. A hybrid-Vlasov model based on the current advance method for the simulation of collisionless magnetized plasma

    SciTech Connect

    Valentini, F. [Dipartimento di Fisica and CNISM, Universita degli Studi della Calabria, Ponte P. Bucci, Cubo 31C, 87036 Arcavacata di Rende (Serbia and Montenegro) (Italy)]. E-mail: valentin@fis.unical.it; Travnicek, P. [Institute of Atmospheric Physics, AS CR, Prague (Czech Republic); Califano, F. [Dipartimento di Fisica and CNISM, Universita di Pisa, Pisa (Italy); Hellinger, P. [Institute of Atmospheric Physics, AS CR, Prague (Czech Republic); Mangeney, A. [LESIA - Observatoire de Paris, Section de Meudon 5, place Jules Janssen, 92195 Meudon Cedex (France)

    2007-07-01

    We present a numerical scheme for the integration of the Vlasov-Maxwell system of equations for a non-relativistic plasma, in the hybrid approximation, where the Vlasov equation is solved for the ion distribution function and the electrons are treated as a fluid. In the Ohm equation for the electric field, effects of electron inertia have been retained, in order to include the small scale dynamics up to characteristic lengths of the order of the electron skin depth. The low frequency approximation is used by neglecting the time derivative of the electric field, i.e. the displacement current in the Ampere equation. The numerical algorithm consists in coupling the splitting method proposed by Cheng and Knorr in 1976 [C.Z. Cheng, G. Knorr, J. Comput. Phys. 22 (1976) 330-351.] and the current advance method (CAM) introduced by Matthews in 1994 [A.P. Matthews, J. Comput. Phys. 112 (1994) 102-116.] In its present version, the code solves the Vlasov-Maxwell equations in a five-dimensional phase space (2-D in the physical space and 3-D in the velocity space) and it is implemented in a parallel version to exploit the computational power of the modern massively parallel supercomputers. The structure of the algorithm and the coupling between the splitting method and the CAM method (extended to the hybrid case) is discussed in detail. Furthermore, in order to test the hybrid-Vlasov code, the numerical results on propagation and damping of linear ion-acoustic modes and time evolution of linear elliptically polarized Alfven waves (including the so-called whistler regime) are compared to the analytical solutions. Finally, the numerical results of the hybrid-Vlasov code on the parametric instability of Alfven waves are compared with those obtained using a two-fluid approach.

  10. Advanced surveillance testbed and background modeling

    Microsoft Academic Search

    Karen A. Singkofer; John E. McCarthy; Howard M. Robbins

    1992-01-01

    The advanced surveillance testbed was developed to provide high-fidelity simulation of space- based electro-optical sensors, their associated signal processing, and multi-target tracking algorithms as well as the testing\\/evaluation of the algorithms. It has a modular design for ease of expansion and maintenance. The testbed begins with scenario definition which includes the definition of satellite constellations, specification of targets, the modeling

  11. Generic models in the advanced IRCM assessment model

    Microsoft Academic Search

    D. P. Forrai; J. J. Maier

    2001-01-01

    The advanced IRCM assessment model (AIRSAM) simulates an infrared (IR) guided missile engaging an aircraft equipped with infrared countermeasures (IRCM). Analysts currently use AIRSAM to predict the most likely IRCM response by an aircraft when engaged. The analyst often attempts to determine responses using IRCM or threat systems that are not characterized in detail. For AIRSAM to be an effective

  12. Generic models in the advanced IRCM assessment model

    Microsoft Academic Search

    David P. Forrai; James J. Maier

    2001-01-01

    The Advanced IRCM Assessment Model (AIRSAM) simulates an infrared (IR) guided missile engaging an aircraft equipped with infrared countermeasures (IRCM). Analysts currently use AIRSAM to predict the most likely IRCM response by an aircraft when engaged. The analyst often attempts to determine responses using IRCM or threat systems that are not characterized in detail. For AIRSAM to be an effective

  13. Supercomputer-based advanced ladar imaging simulator (ALIS)

    NASA Astrophysics Data System (ADS)

    Smith, Duane D.; Nichols, Terry L.; Gatt, Philip; Lee, Kotik K.; Sicking, Charles; Seida, Steven B.; Coker, Charles F.; Perry, Kimberly M.; Coker, Jason S.

    2004-01-01

    The Advanced Ladar Imaging Simulator (ALIS) is a comprehensive multi-dimensional laser radar system simulator that models complex atmospheric scenes combined with high-resolution solid object scenes. The primary functions of ALIS are to serve as a laser radar sensor design tool, data product generator for exploitation, and a decision aid for implementing system designs. This paper focuses on the software structure of the simulator and the challenges that it presents. The ambient atmospheric scene generation is augmented with built-in approximate plume models or with external large-scale Navier-Stokes computational fluid dynamics plume models. The mixed atmosphere and solid object scene is generated via an adaptively meshed, over-sampled voxel representation predicated jointly on the sensor capabilities and scene complexity. To our knowledge, ALIS goes beyond previous ladar simulators with detailed atmospheric turbulence effects and time-dependent plume dispersion models for direct and coherent detection frequency-agile transceivers. ALIS models a wide range of ladar architectures, treating laser coherence properties, receiver electronics noise/transfer functions, and electronics/photon statistical noise. It provides complex amplitude ladar echo "range cubes" (all range reports along a given line-of-sight) for the composite atmosphere-solid scene. The model complexity and its capability to process large (>109) voxel count scenes is accommodated with a portable, scalable software architecture that supports single processors to fine-grained parallel supercomputers.

  14. Modelling the response of a Himalayan watershed to climate change: new insights from linking high resolution in-situ data and remote sensing with an advanced simulation model

    NASA Astrophysics Data System (ADS)

    Ragettli, S.; Pellicciotti, F.; Immerzeel, W.

    2014-12-01

    In high-elevation watersheds of the Himalayan region the correct representation of the internal states and process dynamics in glacio-hydrological models can often not be verified due to missing in-situ measurements. The aim of this study is to provide a fundamental understanding of the hydrology of a Himalayan watershed through the systematic integration of in-situ data in a glacio-hydrological model. We use ground data from the upper Langtang valley in Nepal combined with high resolution satellite data to understand specific processes and test the application of new model components specifically developed. We apply a new model for ablation under debris that takes into account the varying effect of debris thickness on melt rates. A novel approach is tested to reconstruct spatial fields of debris thickness through combination of energy balance modelling, UAV-derived geodetic mass balance and statistical techniques. The systematic integration of in-situ data for model calibration enables the application of a state-of-the art model with many parameters to model glacier evolution and catchment runoff in spite of the lack of continuous long-term historical records. It allows drawing conclusions on the importance of processes that have been suggested as being relevant but never quantified before. The simulations show that 8.7% of total water inputs originate from sub-debris ice melt. 4.5% originate from melted avalanched snow. These components can be locally much more important, since the spatial variability of processes within the valley is high. The model is then used to simulate the response of the catchment to climate change. We show that climate warming leads to an increase in future icemelt and a peak in glacier runoff by mid-century. The increase in total icemelt is due to higher melt rates and large areas that are currently located above the equilibrium line altitude additionally that will contribute to melt. Catchment runoff will not reach below current levels throughout the 21st century due to precipitation increases. Debris covered glacier area will disappear at a slower pace than non-debris covered area. Still, due to the relative climate insensitivity of melt rates below thick debris, the contribution of sub-debris icemelt to runoff will not exceed 10% at all times.

  15. Advanced Chemistry Basins Model

    SciTech Connect

    Blanco, Mario; Cathles, Lawrence; Manhardt, Paul; Meulbroek, Peter; Tang, Yongchun

    2003-02-13

    The objective of this project is to: (1) Develop a database of additional and better maturity indicators for paleo-heat flow calibration; (2) Develop maturation models capable of predicting the chemical composition of hydrocarbons produced by a specific kerogen as a function of maturity, heating rate, etc.; assemble a compositional kinetic database of representative kerogens; (3) Develop a 4 phase equation of state-flash model that can define the physical properties (viscosity, density, etc.) of the products of kerogen maturation, and phase transitions that occur along secondary migration pathways; (4) Build a conventional basin model and incorporate new maturity indicators and data bases in a user-friendly way; (5) Develop an algorithm which combines the volume change and viscosities of the compositional maturation model to predict the chemistry of the hydrocarbons that will be expelled from the kerogen to the secondary migration pathways; (6) Develop an algorithm that predicts the flow of hydrocarbons along secondary migration pathways, accounts for mixing of miscible hydrocarbon components along the pathway, and calculates the phase fractionation that will occur as the hydrocarbons move upward down the geothermal and fluid pressure gradients in the basin; and (7) Integrate the above components into a functional model implemented on a PC or low cost workstation.

  16. Aviation Safety Simulation Model

    NASA Technical Reports Server (NTRS)

    Houser, Scott; Yackovetsky, Robert (Technical Monitor)

    2001-01-01

    The Aviation Safety Simulation Model is a software tool that enables users to configure a terrain, a flight path, and an aircraft and simulate the aircraft's flight along the path. The simulation monitors the aircraft's proximity to terrain obstructions, and reports when the aircraft violates accepted minimum distances from an obstruction. This model design facilitates future enhancements to address other flight safety issues, particularly air and runway traffic scenarios. This report shows the user how to build a simulation scenario and run it. It also explains the model's output.

  17. A case study of verification, validation, and accreditation for advanced distributed simulation

    Microsoft Academic Search

    Ernest H. Page; Bradford S. Canova; John A. Tufarolo

    1997-01-01

    The techniques and methodologies for verification and validation of software-based systems have arguably realized their greatest utility within the context of simulation. Advanced Distributed Simulation (ADS), a major initiative within the defense modeling and simulation community, presents a variety of challenges to the classical approaches. A case study of the development process and concomitant verification and validation activities for the

  18. Advancing the Art of Simulation in the Social Sciences

    Microsoft Academic Search

    Robert Axelrod

    1997-01-01

    Advancing the state of the art of simulation in the social sciences requires appreciating the unique value of simulation as a third way of doing science, in contrast to both induction and deduction. Simulation can be an effective tool for discovering surprising consequences of simple assumptions. This essay offers advice for doing simulation research, focusing on the programming of a

  19. Nuclear Energy -- Knowledge Base for Advanced Modeling and Simulation (NE-KAMS) Code Verification and Validation Data Standards and Requirements: Fluid Dynamics Version 1.0

    SciTech Connect

    Greg Weirs; Hyung Lee

    2011-09-01

    V&V and UQ are the primary means to assess the accuracy and reliability of M&S and, hence, to establish confidence in M&S. Though other industries are establishing standards and requirements for the performance of V&V and UQ, at present, the nuclear industry has not established such standards or requirements. However, the nuclear industry is beginning to recognize that such standards are needed and that the resources needed to support V&V and UQ will be very significant. In fact, no single organization has sufficient resources or expertise required to organize, conduct and maintain a comprehensive V&V and UQ program. What is needed is a systematic and standardized approach to establish and provide V&V and UQ resources at a national or even international level, with a consortium of partners from government, academia and industry. Specifically, what is needed is a structured and cost-effective knowledge base that collects, evaluates and stores verification and validation data, and shows how it can be used to perform V&V and UQ, leveraging collaboration and sharing of resources to support existing engineering and licensing procedures as well as science-based V&V and UQ processes. The Nuclear Energy Knowledge base for Advanced Modeling and Simulation (NE-KAMS) is being developed at the Idaho National Laboratory in conjunction with Bettis Laboratory, Sandia National Laboratories, Argonne National Laboratory, Utah State University and others with the objective of establishing a comprehensive and web-accessible knowledge base to provide V&V and UQ resources for M&S for nuclear reactor design, analysis and licensing. The knowledge base will serve as an important resource for technical exchange and collaboration that will enable credible and reliable computational models and simulations for application to nuclear power. NE-KAMS will serve as a valuable resource for the nuclear industry, academia, the national laboratories, the U.S. Nuclear Regulatory Commission (NRC) and the public and will help ensure the safe, economical and reliable operation of existing and future nuclear reactors.

  20. Mobile advanced simulation for primary care pediatricians: Spanish Experience

    E-print Network

    Manstein, Dietmar J.

    Mobile advanced simulation for primary care pediatricians: Spanish Experience Purpose of the study: Advanced simulation uses to be focused on hospital and emergencies personnel. Primary care pediatricians and initiate the adequate treatment. We report the results of the Spanish Society of Primary Care Pediatrics

  1. Aeroheating model advancements featuring electroless metallic plating

    NASA Technical Reports Server (NTRS)

    Stalmach, C. J., Jr.; Goodrich, W. D.

    1976-01-01

    Discussed are advancements in wind tunnel model construction methods and hypersonic test data demonstrating the methods. The general objective was to develop model fabrication methods for improved heat transfer measuring capability at less model cost. A plated slab model approach was evaluated with cast models containing constantan wires that formed single-wire-to-plate surface thermocouple junctions with a seamless skin of electroless nickel alloy. The surface of a space shuttle orbiter model was selectively plated with scaled tiles to simulate, with high fidelity, the probable misalignments of the heatshield tiles on a flight vehicle. Initial, Mach 8 heating results indicated a minor effect of tile misalignment roughness on boundary layer transition, implying a possible relaxation of heatshield manufacturing tolerances. Some loss of the plated tiles was experienced when the model was tested at high heating rates.

  2. ADVANCED MIXING MODELS

    SciTech Connect

    Lee, S.; Dimenna, R.; Tamburello, D.

    2011-02-14

    The process of recovering and processing High Level Waste (HLW) the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank with one to four mixers (pumps) located within the tank. The typical criteria to establish a mixed condition in a tank are based on the number of pumps in operation and the time duration of operation. To ensure that a mixed condition is achieved, operating times are typically set conservatively long. This approach results in high operational costs because of the long mixing times and high maintenance and repair costs for the same reason. A significant reduction in both of these costs might be realized by reducing the required mixing time based on calculating a reliable indicator of mixing with a suitably validated computer code. The focus of the present work is to establish mixing criteria applicable to miscible fluids, with an ultimate goal of addressing waste processing in HLW tanks at SRS and quantifying the mixing time required to suspend sludge particles with the submersible jet pump. A single-phase computational fluid dynamics (CFD) approach was taken for the analysis of jet flow patterns with an emphasis on the velocity decay and the turbulent flow evolution for the farfield region from the pump. Literature results for a turbulent jet flow are reviewed, since the decay of the axial jet velocity and the evolution of the jet flow patterns are important phenomena affecting sludge suspension and mixing operations. The work described in this report suggests a basis for further development of the theory leading to the identified mixing indicators, with benchmark analyses demonstrating their consistency with widely accepted correlations. Although the indicators are somewhat generic in nature, they are applied to Savannah River Site (SRS) waste tanks to provide a better, physically based estimate of the required mixing time. Waste storage tanks at SRS contain settled sludge which varies in height from zero to 10 ft. The sludge has been characterized and modeled as micron-sized solids, typically 1 to 5 microns, at weight fractions as high as 20 to 30 wt%, specific gravities to 1.4, and viscosities up to 64 cp during motion. The sludge is suspended and mixed through the use of submersible slurry jet pumps. To suspend settled sludge, water is added to the tank as a slurry medium and stirred with the jet pump. Although there is considerable technical literature on mixing and solid suspension in agitated tanks, very little literature has been published on jet mixing in a large-scale tank. One of the main objectives in the waste processing is to provide feed of a uniform slurry composition at a certain weight percentage (e.g. typically {approx}13 wt% at SRS) over an extended period of time. In preparation of the sludge for slurrying, several important questions have been raised with regard to sludge suspension and mixing of the solid suspension in the bulk of the tank: (1) How much time is required to prepare a slurry with a uniform solid composition? (2) How long will it take to suspend and mix the sludge for uniform composition in any particular waste tank? (3) What are good mixing indicators to answer the questions concerning sludge mixing stated above in a general fashion applicable to any waste tank/slurry pump geometry and fluid/sludge combination?

  3. The Advanced Regional Prediction System (ARPS) - A multi-scale nonhydrostatic atmospheric simulation and prediction tool. Part II: Model physics and applications

    Microsoft Academic Search

    M. Xue; K. K. Droegemeier; V. Wong; A. Shapiro; K. Brewster; F. Carr; D. Weber; Y. Liu; D. Wang

    2001-01-01

    Summary In Part I of this paper series, the dynamic equations, numerical solution procedures and the parameterizations of subgrid-scale and PBL turbulence of the Advanced Regional Prediction System (ARPS) were described. The dynamic and numerical framework of the model was verified using idealized and real mountain flow cases and an idealized density current. In this Part II, we present the

  4. Interoperable mesh and geometry tools for advanced petascale simulations

    SciTech Connect

    Diachin, L; Bauer, A; Fix, B; Kraftcheck, J; Jansen, K; Luo, X; Miller, M; Ollivier-Gooch, C; Shephard, M; Tautges, T; Trease, H

    2007-07-04

    SciDAC applications have a demonstrated need for advanced software tools to manage the complexities associated with sophisticated geometry, mesh, and field manipulation tasks, particularly as computer architectures move toward the petascale. The Center for Interoperable Technologies for Advanced Petascale Simulations (ITAPS) will deliver interoperable and interchangeable mesh, geometry, and field manipulation services that are of direct use to SciDAC applications. The premise of our technology development goal is to provide such services as libraries that can be used with minimal intrusion into application codes. To develop these technologies, we focus on defining a common data model and datastructure neutral interfaces that unify a number of different services such as mesh generation and improvement, front tracking, adaptive mesh refinement, shape optimization, and solution transfer operations. We highlight the use of several ITAPS services in SciDAC applications.

  5. ADVANCED MIXING MODELS

    SciTech Connect

    Lee, S; Richard Dimenna, R; David Tamburello, D

    2008-11-13

    The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank with one to four dual-nozzle jet mixers located within the tank. The typical criteria to establish a mixed condition in a tank are based on the number of pumps in operation and the time duration of operation. To ensure that a mixed condition is achieved, operating times are set conservatively long. This approach results in high operational costs because of the long mixing times and high maintenance and repair costs for the same reason. A significant reduction in both of these costs might be realized by reducing the required mixing time based on calculating a reliable indicator of mixing with a suitably validated computer code. The work described in this report establishes the basis for further development of the theory leading to the identified mixing indicators, the benchmark analyses demonstrating their consistency with widely accepted correlations, and the application of those indicators to SRS waste tanks to provide a better, physically based estimate of the required mixing time. Waste storage tanks at SRS contain settled sludge which varies in height from zero to 10 ft. The sludge has been characterized and modeled as micron-sized solids, typically 1 to 5 microns, at weight fractions as high as 20 to 30 wt%, specific gravities to 1.4, and viscosities up to 64 cp during motion. The sludge is suspended and mixed through the use of submersible slurry jet pumps. To suspend settled sludge, water is added to the tank as a slurry medium and stirred with the jet pump. Although there is considerable technical literature on mixing and solid suspension in agitated tanks, very little literature has been published on jet mixing in a large-scale tank. If shorter mixing times can be shown to support Defense Waste Processing Facility (DWPF) or other feed requirements, longer pump lifetimes can be achieved with associated operational cost and schedule savings. The focus of the present work is to establish mixing criteria associated with the waste processing at SRS and to quantify the mixing time required to suspend sludge particles with the submersible jet pump. Literature results for a turbulent jet flow are reviewed briefly, since the decay of the axial jet velocity and the evolution of the jet flow patterns are important phenomena affecting sludge suspension and mixing operations. One of the main objectives in the waste processing is to provide the DWPF a uniform slurry composition at a certain weight percentage (typically {approx}13 wt%) over an extended period of time. In preparation of the sludge for slurrying to DWPF, several important questions have been raised with regard to sludge suspension and mixing of the solid suspension in the bulk of the tank: (1) How much time is required to prepare a slurry with a uniform solid composition for DWPF? (2) How long will it take to suspend and mix the sludge for uniform composition in any particular waste tank? (3) What are good mixing indicators to answer the questions concerning sludge mixing stated above in a general fashion applicable to any waste tank/slurry pump geometry and fluid/sludge combination? Grenville and Tilton (1996) investigated the mixing process by giving a pulse of tracer (electrolyte) through the submersible jet nozzle and by monitoring the conductivity at three locations within the cylindrical tank. They proposed that the mixing process was controlled by the turbulent kinetic energy dissipation rate in the region far away from the jet entrance. They took the energy dissipation rates in the regions remote from the nozzle to be proportional to jet velocity and jet diameter at that location. The reduction in the jet velocity was taken to be proportional to the nozzle velocity and distance from the nozzle. Based on their analysis, a correlation was proposed. The proposed correlation was shown to be valid over a wide range of Reynolds numbers (50,000 to 300,000) with a relative standard deviation of {+-} 11.83%. An improved correlat

  6. A comparison of cirrus cloud observations from the NASA ATTREX-3 field mission with simulations from the NCAR atmospheric CESM model (CAM5) coupled with an advanced cirrus cloud model (CARMA).

    NASA Astrophysics Data System (ADS)

    Maloney, C.; Toon, O. B.; Bardeen, C.; Diskin, G. S.; McGill, M. J.; Rollins, A. W.; Thornberry, T. D.; Woods, S.

    2014-12-01

    Cirrus clouds play an important role in the vertical transport of water vapor between the upper troposphere and lower stratosphere in the Tropical Tropopause Layer (TTL). Unfortunately, the physical limitations of observing the TTL and the model uncertainty surrounding cirrus clouds prevent a full understanding of the properties of cirrus and their role in water vapor transport. However, recently NASA's ATTREX 3 field mission was undertaken to observe water vapor and cirrus properties in the TTL. The high altitude Global Hawk aircraft gathered a unique in-situ data set from the tropical Western Pacific. This region is known to be crucial for the upward motion of water vapor and chemical transport in the atmosphere, but has been observed infrequently. With the ATTREX data, we investigate the differences between in situ and anvil cirrus, and we assess the relative frequency of heterogeneous and homogenous ice nucleation. Alongside the observational data, we ran NCAR's CESM model and coupled it to an advanced cirrus model (CARMA). The model was run at a 1x1 degree resolution along the aircraft's flight track to simulate the observations. We compare the CAM5/CARMA simulations to the aircraft observations to investigate the effectiveness of the model in reproducing the aircraft data.

  7. Naval threat countermeasure simulator and the IR_CRUISE_missiles models for the generation of infrared (IR) videos of maritime targets and background for input into advanced imaging IR seekers

    NASA Astrophysics Data System (ADS)

    Taczak, Thomas M.; Dries, John W.; Gover, Robert E.; Snapp, Mary Ann; Williams, Elmer F.; Cahill, Colin P.

    2002-07-01

    A new hardware-in-the-loop modeling technique was developed at the US Naval Research Laboratory (NRL) for the evaluation of IR countermeasures against advanced IR imaging anti-ship cruise missiles. The research efforts involved the creation of tools to generate accurate IR imagery and synthesize video to inject in to real-world threat simulators. A validation study was conducted to verify the accuracy and limitations of the techniques that were developed.

  8. Modeling Molecular Dynamics from Simulations

    SciTech Connect

    Hinrichs, Nina Singhal (University of Chicago) [University of Chicago

    2009-01-28

    Many important processes in biology occur at the molecular scale. A detailed understanding of these processes can lead to significant advances in the medical and life sciences. For example, many diseases are caused by protein aggregation or misfolding. One approach to studying these systems is to use physically-based computational simulations to model the interactions and movement of the molecules. While molecular simulations are computationally expensive, it is now possible to simulate many independent molecular dynamics trajectories in a parallel fashion by using super- or distributed- computing methods such as Folding@Home or Blue Gene. The analysis of these large, high-dimensional data sets presents new computational challenges. In this seminar, I will discuss a novel approach to analyzing large ensembles of molecular dynamics trajectories to generate a compact model of the dynamics. This model groups conformations into discrete states and describes the dynamics as Markovian, or history-independent, transitions between the states. I will discuss why the Markovian state model (MSM) is suitable for macromolecular dynamics, and how it can be used to answer many interesting and relevant questions about the molecular system. I will also discuss many of the computational and statistical challenges in building such a model, such as how to appropriately cluster conformations, determine the statistical reliability, and efficiently design new simulations.

  9. Advanced Potential Energy Surfaces for Condensed Phase Simulation

    NASA Astrophysics Data System (ADS)

    Demerdash, Omar; Yap, Eng-Hui; Head-Gordon, Teresa

    2014-04-01

    Computational modeling at the atomistic and mesoscopic levels has undergone dramatic development in the past 10 years to meet the challenge of adequately accounting for the many-body nature of intermolecular interactions. At the heart of this challenge is the ability to identify the strengths and specific limitations of pairwise-additive interactions, to improve classical models to explicitly account for many-body effects, and consequently to enhance their ability to describe a wider range of reference data and build confidence in their predictive capacity. However, the corresponding computational cost of these advanced classical models increases significantly enough that statistical convergence of condensed phase observables becomes more difficult to achieve. Here we review a hierarchy of potential energy surface models used in molecular simulations for systems with many degrees of freedom that best meet the trade-off between accuracy and computational speed in order to define a sweet spot for a given scientific problem of interest.

  10. Advanced potential energy surfaces for condensed phase simulation.

    PubMed

    Demerdash, Omar; Yap, Eng-Hui; Head-Gordon, Teresa

    2014-01-01

    Computational modeling at the atomistic and mesoscopic levels has undergone dramatic development in the past 10 years to meet the challenge of adequately accounting for the many-body nature of intermolecular interactions. At the heart of this challenge is the ability to identify the strengths and specific limitations of pairwise-additive interactions, to improve classical models to explicitly account for many-body effects, and consequently to enhance their ability to describe a wider range of reference data and build confidence in their predictive capacity. However, the corresponding computational cost of these advanced classical models increases significantly enough that statistical convergence of condensed phase observables becomes more difficult to achieve. Here we review a hierarchy of potential energy surface models used in molecular simulations for systems with many degrees of freedom that best meet the trade-off between accuracy and computational speed in order to define a sweet spot for a given scientific problem of interest. PMID:24328448

  11. Theory Modeling and Simulation

    SciTech Connect

    Shlachter, Jack [Los Alamos National Laboratory

    2012-08-23

    Los Alamos has a long history in theory, modeling and simulation. We focus on multidisciplinary teams that tackle complex problems. Theory, modeling and simulation are tools to solve problems just like an NMR spectrometer, a gas chromatograph or an electron microscope. Problems should be used to define the theoretical tools needed and not the other way around. Best results occur when theory and experiments are working together in a team.

  12. A Virtual Engineering Framework for Simulating Advanced Power System

    SciTech Connect

    Mike Bockelie; Dave Swensen; Martin Denison; Stanislav Borodai

    2008-06-18

    In this report is described the work effort performed to provide NETL with VE-Suite based Virtual Engineering software and enhanced equipment models to support NETL's Advanced Process Engineering Co-simulation (APECS) framework for advanced power generation systems. Enhancements to the software framework facilitated an important link between APECS and the virtual engineering capabilities provided by VE-Suite (e.g., equipment and process visualization, information assimilation). Model enhancements focused on improving predictions for the performance of entrained flow coal gasifiers and important auxiliary equipment (e.g., Air Separation Units) used in coal gasification systems. In addition, a Reduced Order Model generation tool and software to provide a coupling between APECS/AspenPlus and the GE GateCycle simulation system were developed. CAPE-Open model interfaces were employed where needed. The improved simulation capability is demonstrated on selected test problems. As part of the project an Advisory Panel was formed to provide guidance on the issues on which to focus the work effort. The Advisory Panel included experts from industry and academics in gasification, CO2 capture issues, process simulation and representatives from technology developers and the electric utility industry. To optimize the benefit to NETL, REI coordinated its efforts with NETL and NETL funded projects at Iowa State University, Carnegie Mellon University and ANSYS/Fluent, Inc. The improved simulation capabilities incorporated into APECS will enable researchers and engineers to better understand the interactions of different equipment components, identify weaknesses and processes needing improvement and thereby allow more efficient, less expensive plants to be developed and brought on-line faster and in a more cost-effective manner. These enhancements to APECS represent an important step toward having a fully integrated environment for performing plant simulation and engineering. Furthermore, with little effort the modeling capabilities described in this report can be extended to support other DOE programs, such as ultra super critical boiler development, oxy-combustion boiler development or modifications to existing plants to include CO2 capture and sequestration.

  13. Simulating the Value of Advanced Electricity Storage: Initial Results from a Case Study

    E-print Network

    Ford, Andrew

    , Inc in bulk energy storage using GCAES, the General Compression Advanced Energy StorageTM technology1 Simulating the Value of Advanced Electricity Storage: Initial Results from a Case Study's plans for the storage project and for the modeling system. #12;2 Background on Energy Storage Energy

  14. New Developments in the Simulation of Advanced Accelerator Concepts

    SciTech Connect

    Paul, K.; Cary, J.R.; Cowan, B.; Bruhwiler, D.L.; Geddes, C.G.R.; Mullowney, P.J.; Messmer, P.; Esarey, E.; Cormier-Michel, E.; Leemans, W.P.; Vay, J.-L.

    2008-09-10

    Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating>10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of ~;;2,000 as compared to standard particle-in-cell.

  15. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  16. AGRICULTURAL SIMULATION MODEL (AGSIM)

    EPA Science Inventory

    AGSIM is a large-scale econometric simulation model of regional crop and national livestock production in the United States. The model was initially developed to analyze the aggregate economic impacts of a wide variety issues facing agriculture, such as technological change, pest...

  17. Brush seal numerical simulation: Concepts and advances

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Kudriavtsev, V. V.

    1994-01-01

    The development of the brush seal is considered to be most promising among the advanced type seals that are presently in use in the high speed turbomachinery. The brush is usually mounted on the stationary portions of the engine and has direct contact with the rotating element, in the process of limiting the 'unwanted' leakage flows between stages, or various engine cavities. This type of sealing technology is providing high (in comparison with conventional seals) pressure drops due mainly to the high packing density (around 100 bristles/sq mm), and brush compliance with the rotor motions. In the design of modern aerospace turbomachinery leakage flows between the stages must be minimal, thus contributing to the higher efficiency of the engine. Use of the brush seal instead of the labyrinth seal reduces the leakage flow by one order of magnitude. Brush seals also have been found to enhance dynamic performance, cost less, and are lighter than labyrinth seals. Even though industrial brush seals have been successfully developed through extensive experimentation, there is no comprehensive numerical methodology for the design or prediction of their performance. The existing analytical/numerical approaches are based on bulk flow models and do not allow the investigation of the effects of brush morphology (bristle arrangement), or brushes arrangement (number of brushes, spacing between them), on the pressure drops and flow leakage. An increase in the brush seal efficiency is clearly a complex problem that is closely related to the brush geometry and arrangement, and can be solved most likely only by means of a numerically distributed model.

  18. Advanced radiometric and interferometric milimeter-wave scene simulations

    NASA Technical Reports Server (NTRS)

    Hauss, B. I.; Moffa, P. J.; Steele, W. G.; Agravante, H.; Davidheiser, R.; Samec, T.; Young, S. K.

    1993-01-01

    Smart munitions and weapons utilize various imaging sensors (including passive IR, active and passive millimeter-wave, and visible wavebands) to detect/identify targets at short standoff ranges and in varied terrain backgrounds. In order to design and evaluate these sensors under a variety of conditions, a high-fidelity scene simulation capability is necessary. Such a capability for passive millimeter-wave scene simulation exists at TRW. TRW's Advanced Radiometric Millimeter-Wave Scene Simulation (ARMSS) code is a rigorous, benchmarked, end-to-end passive millimeter-wave scene simulation code for interpreting millimeter-wave data, establishing scene signatures and evaluating sensor performance. In passive millimeter-wave imaging, resolution is limited due to wavelength and aperture size. Where high resolution is required, the utility of passive millimeter-wave imaging is confined to short ranges. Recent developments in interferometry have made possible high resolution applications on military platforms. Interferometry or synthetic aperture radiometry allows the creation of a high resolution image with a sparsely filled aperture. Borrowing from research work in radio astronomy, we have developed and tested at TRW scene reconstruction algorithms that allow the recovery of the scene from a relatively small number of spatial frequency components. In this paper, the TRW modeling capability is described and numerical results are presented.

  19. Multi-physics nuclear reactor simulator for advanced nuclear engineering education

    SciTech Connect

    Yamamoto, A. [Nagoya Univ., Furo-cho, Chikusa-ku, Nagoya (Japan); Dept. of the Quantum Science and Energy Engineering Field of Materials Physics, Energy Engineering Div., Nagoya Univ. (Japan)

    2012-07-01

    Multi-physics nuclear reactor simulator, which aims to utilize for advanced nuclear engineering education, is being introduced to Nagoya Univ.. The simulator consists of the 'macroscopic' physics simulator and the 'microscopic' physics simulator. The former performs real time simulation of a whole nuclear power plant. The latter is responsible to more detail numerical simulations based on the sophisticated and precise numerical models, while taking into account the plant conditions obtained in the macroscopic physics simulator. Steady-state and kinetics core analyses, fuel mechanical analysis, fluid dynamics analysis, and sub-channel analysis can be carried out in the microscopic physics simulator. Simulation calculations are carried out through dedicated graphical user interface and the simulation results, i.e., spatial and temporal behaviors of major plant parameters are graphically shown. The simulator will provide a bridge between the 'theories' studied with textbooks and the 'physical behaviors' of actual nuclear power plants. (authors)

  20. New models for PA advancement. Forum discussion.

    PubMed

    Fitzpatrick, K T; Huntington, C G; Lyons, B A; Marion, G S; Reichman, J

    1993-09-01

    Many PAs are grappling with the problem of how to best advance their careers. In this roundtable, the participants discuss traditional methods of advancement and examine the need for new models. PMID:10136589

  1. Mixed Virtual/Physical Reality Simulation for Advanced Training

    E-print Network

    Slatton, Clint

    Mixed Virtual/Physical Reality Simulation for Advanced Training The University of Florida (virtual/ physical) reality simulator system for the use of healthcare, military and other industries processes and anatomy and their interplay with medical procedures and interventions Equipment: to gain

  2. Revolutions in energy through modeling and simulation

    SciTech Connect

    Tatro, M.; Woodard, J.

    1998-08-01

    The development and application of energy technologies for all aspects from generation to storage have improved dramatically with the advent of advanced computational tools, particularly modeling and simulation. Modeling and simulation are not new to energy technology development, and have been used extensively ever since the first commercial computers were available. However, recent advances in computing power and access have broadened the extent and use, and, through increased fidelity (i.e., accuracy) of the models due to greatly enhanced computing power, the increased reliance on modeling and simulation has shifted the balance point between modeling and experimentation. The complex nature of energy technologies has motivated researchers to use these tools to understand better performance, reliability and cost issues related to energy. The tools originated in sciences such as the strength of materials (nuclear reactor containment vessels); physics, heat transfer and fluid flow (oil production); chemistry, physics, and electronics (photovoltaics); and geosciences and fluid flow (oil exploration and reservoir storage). Other tools include mathematics, such as statistics, for assessing project risks. This paper describes a few advancements made possible by these tools and explores the benefits and costs of their use, particularly as they relate to the acceleration of energy technology development. The computational complexity ranges from basic spreadsheets to complex numerical simulations using hardware ranging from personal computers (PCs) to Cray computers. In all cases, the benefits of using modeling and simulation relate to lower risks, accelerated technology development, or lower cost projects.

  3. Multiphase flow in the advanced fluid dynamics model

    Microsoft Academic Search

    W. R. Bohl; D. Wilhelm; J. Berthier; F. P. Parker; S. Ichikawa; L. Goutagny; H. Ninokata

    1988-01-01

    This paper describes the modeling used in the Advanced Fluid Dynamics Model (AFDM), a computer code to investigate new approaches to simulating severe accidents in fast reactors. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, the dominant liquid, and the continuous phase.

  4. Hybrid and Electric Advanced Vehicle Systems Simulation

    NASA Technical Reports Server (NTRS)

    Beach, R. F.; Hammond, R. A.; Mcgehee, R. K.

    1985-01-01

    Predefined components connected to represent wide variety of propulsion systems. Hybrid and Electric Advanced Vehicle System (HEAVY) computer program is flexible tool for evaluating performance and cost of electric and hybrid vehicle propulsion systems. Allows designer to quickly, conveniently, and economically predict performance of proposed drive train.

  5. State of the Art Assessment of Simulation in Advanced Materials Development

    NASA Technical Reports Server (NTRS)

    Wise, Kristopher E.

    2008-01-01

    Advances in both the underlying theory and in the practical implementation of molecular modeling techniques have increased their value in the advanced materials development process. The objective is to accelerate the maturation of emerging materials by tightly integrating modeling with the other critical processes: synthesis, processing, and characterization. The aims of this report are to summarize the state of the art of existing modeling tools and to highlight a number of areas in which additional development is required. In an effort to maintain focus and limit length, this survey is restricted to classical simulation techniques including molecular dynamics and Monte Carlo simulations.

  6. Advanced modeling of prompt fission neutrons

    SciTech Connect

    Talou, Patrick [Los Alamos National Laboratory

    2009-01-01

    Theoretical and numerical studies of prompt fission neutrons are presented. The main results of the Los Alamos model often used in nuclear data evaluation work are reviewed briefly, and a preliminary assessment of uncertainties associated with the evaluated prompt fission neutron spectrum for n (0.5 MeV)+{sup 239}Pu is discussed. Advanced modeling of prompt fission neutrons is done by Monte Carlo simulations of the evaporation process of the excited primary fission fragments. The successive emissions of neutrons are followed in the statistical formalism framework, and detailed information, beyond average quantities, can be inferred. This approach is applied to the following reactions: {sup 252}Cf (sf), n{sub th} + {sup 239}Pu, n (0.5 MeV)+{sup 235}U, and {sup 236}Pu (sf). A discussion on the merits and present limitations of this approach concludes this presentation.

  7. Models, Simulations, and Games: A Survey.

    ERIC Educational Resources Information Center

    Shubik, Martin; Brewer, Garry D.

    A Rand evaluation of activity and products of gaming, model-building, and simulation carried out under the auspices of the Defense Advanced Research Projects Agency aimed not only to assess the usefulness of gaming in military-political policymaking, but also to contribute to the definition of common standards and the refinement of objectives for…

  8. Advanced Combustion Modeling for Complex Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Ham, Frank Stanford

    2005-01-01

    The next generation of aircraft engines will need to pass stricter efficiency and emission tests. NASA's Ultra-Efficient Engine Technology (UEET) program has set an ambitious goal of 70% reduction of NO(x) emissions and a 15% increase in fuel efficiency of aircraft engines. We will demonstrate the state-of-the-art combustion tools developed a t Stanford's Center for Turbulence Research (CTR) as part of this program. In the last decade, CTR has spear-headed a multi-physics-based combustion modeling program. Key technologies have been transferred to the aerospace industry and are currently being used for engine simulations. In this demo, we will showcase the next-generation combustion modeling tools that integrate a very high level of detailed physics into advanced flow simulation codes. Combustor flows involve multi-phase physics with liquid fuel jet breakup, evaporation, and eventual combustion. Individual components of the simulation are verified against complex test cases and show excellent agreement with experimental data.

  9. Unraveling the hydrology of a Himalayan catchment through integration of high resolution in situ data and remote sensing with an advanced simulation model

    NASA Astrophysics Data System (ADS)

    Ragettli, S.; Pellicciotti, F.; Immerzeel, W. W.; Miles, E. S.; Petersen, L.; Heynen, M.; Shea, J. M.; Stumm, D.; Joshi, S.; Shrestha, A.

    2015-04-01

    The hydrology of high-elevation watersheds of the Hindu Kush-Himalaya region (HKH) is poorly known. The correct representation of internal states and process dynamics in glacio-hydrological models can often not be verified due to missing in situ measurements. We use a new set of detailed ground data from the upper Langtang valley in Nepal to systematically guide a state-of-the art glacio-hydrological model through a parameter assigning process with the aim to understand the hydrology of the catchment and contribution of snow and ice processes to runoff. 14 parameters are directly calculated on the basis of local data, and 13 parameters are calibrated against 5 different datasets of in situ or remote sensing data. Spatial fields of debris thickness are reconstructed through a novel approach that employs data from an Unmanned Aerial Vehicle (UAV), energy balance modeling and statistical techniques. The model is validated against measured catchment runoff (Nash-Sutcliffe efficiency 0.87) and modeled snow cover is compared to Landsat snow cover. The advanced representation of processes allowed assessing the role played by avalanching for runoff for the first time for a Himalayan catchment (5% of annual water inputs to the hydrological system are due to snow redistribution) and to quantify the hydrological significance of sub-debris ice melt (9% of annual water inputs). Snowmelt is the most important contributor to total runoff during the hydrological year 2012/2013 (representing 40% of all sources), followed by rainfall (34%) and ice melt (26%). A sensitivity analysis is used to assess the efficiency of the monitoring network and identify the timing and location of field measurements that constrain model uncertainty. The methodology to set up a glacio-hydrological model in high-elevation regions presented in this study can be regarded as a benchmark for modelers in the HKH seeking to evaluate their calibration approach, their experimental setup and thus to reduce the predictive model uncertainty.

  10. Measurement and modeling of advanced coal conversion processes

    SciTech Connect

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. (Advanced Fuel Research, Inc., East Hartford, CT (United States) Brigham Young Univ., Provo, UT (United States))

    1991-01-01

    The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

  11. Rapid implementation of advanced constitutive models

    NASA Astrophysics Data System (ADS)

    Starman, Bojan; Halilovi?, Miroslav; Vrh, Marko; Štok, Boris

    2013-12-01

    This paper presents a methodology based on the NICE integration scheme [1, 2] for simple and rapid numerical implementation of a class of plasticity constitutive models. In this regard, an algorithm is purposely developed for the implementation of newly developed advanced constitutive models into explicit finite element framework. The methodology follows the organization of the problem state variables into an extended form, which allows the constitutive models' equations to be organized in such a way, that the algorithm can be optionally extended with minimal effort to integrate also evolution equations related to a description of other specific phenomena, such as damage, distortional hardening, phase transitions, degradation etc. To confirm simplicity of the program implementation, computational robustness, effectiveness and improved accuracy of the implemented integration algorithm, a deep drawing simulation of the cylindrical cup is considered as the case study, performed in ABAQUS/Explicit. As a fairly complex considered model, the YLD2004-18p model [3, 4] is first implemented via external subroutine VUMAT. Further, to give additional proof of the simplicity of the proposed methodology, a combination of the YLD2004-18p model and Gurson-Tvergaard-Needleman model (GTN) is considered. As demonstrated, the implementation is really obtained in a very simple way.

  12. Using CONFIG for Simulation of Operation of Water Recovery Subsystems for Advanced Control Software Evaluation

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Flores, Luis; Fleming, Land; Throop, Daiv

    2002-01-01

    A hybrid discrete/continuous simulation tool, CONFIG, has been developed to support evaluation of the operability life support systems. CON FIG simulates operations scenarios in which flows and pressures change continuously while system reconfigurations occur as discrete events. In simulations, intelligent control software can interact dynamically with hardware system models. CONFIG simulations have been used to evaluate control software and intelligent agents for automating life support systems operations. A CON FIG model of an advanced biological water recovery system has been developed to interact with intelligent control software that is being used in a water system test at NASA Johnson Space Center

  13. Simulating CCDs for the Chandra Advanced CCD Imaging Spectrometer

    E-print Network

    L. K. Townsley; P. S. Broos; G. Chartas; E. Moskalenko; J. A. Nousek; G. G. Pavlov

    2001-10-31

    We have implemented a Monte Carlo algorithm to model and predict the response of various kinds of CCDs to X-ray photons and minimally-ionizing particles and have applied this model to the CCDs in the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer. This algorithm draws on empirical results and predicts the response of all basic types of X-ray CCD devices. It relies on new solutions of the diffusion equation, including recombination, to predict the radial charge cloud distribution in field-free regions of CCDs. By adjusting the size of the charge clouds, we can reproduce the event grade distribution seen in calibration data. Using a model of the channel stops developed here and an insightful treatment of the insulating layer under the gate structure developed at MIT, we are able to reproduce all notable features in ACIS calibration spectra. The simulator is used to reproduce ground and flight calibration data from ACIS, thus confirming its fidelity. It can then be used for a variety of calibration tasks, such as generating spectral response matrices for spectral fitting of astrophysical sources, quantum efficiency estimation, and modeling of photon pile-up.

  14. Development of Design Technology on Thermal-Hydraulic Performance in Tight-Lattice Rod Bundle: IV Large Paralleled Simulation by the Advanced Two-fluid Model Code

    NASA Astrophysics Data System (ADS)

    Misawa, Takeharu; Yoshida, Hiroyuki; Akimoto, Hajime

    In Japan Atomic Energy Agency (JAEA), the Innovative Water Reactor for Flexible Fuel Cycle (FLWR) has been developed. For thermal design of FLWR, it is necessary to develop analytical method to predict boiling transition of FLWR. Japan Atomic Energy Agency (JAEA) has been developing three-dimensional two-fluid model analysis code ACE-3D, which adopts boundary fitted coordinate system to simulate complex shape channel flow. In this paper, as a part of development of ACE-3D to apply to rod bundle analysis, introduction of parallelization to ACE-3D and assessments of ACE-3D are shown. In analysis of large-scale domain such as a rod bundle, even two-fluid model requires large number of computational cost, which exceeds upper limit of memory amount of 1 CPU. Therefore, parallelization was introduced to ACE-3D to divide data amount for analysis of large-scale domain among large number of CPUs, and it is confirmed that analysis of large-scale domain such as a rod bundle can be performed by parallel computation with keeping parallel computation performance even using large number of CPUs. ACE-3D adopts two-phase flow models, some of which are dependent upon channel geometry. Therefore, analyses in the domains, which simulate individual subchannel and 37 rod bundle, are performed, and compared with experiments. It is confirmed that the results obtained by both analyses using ACE-3D show agreement with past experimental result qualitatively.

  15. Preliminary simulation of an advanced, hingless rotor XV-15 tilt-rotor aircraft

    NASA Technical Reports Server (NTRS)

    Mcveigh, M. A.

    1976-01-01

    The feasibility of the tilt-rotor concept was verified through investigation of the performance, stability and handling qualities of the XV-15 tilt rotor. The rotors were replaced by advanced-technology fiberglass/composite hingless rotors of larger diameter, combined with an advanced integrated fly-by-wire control system. A parametric simulation model of the HRXV-15 was developed, model was used to define acceptable preliminary ranges of primary and secondary control schedules as functions of the flight parameters, to evaluate performance, flying qualities and structural loads, and to have a Boeing-Vertol pilot conduct a simulated flight test evaluation of the aircraft.

  16. Alignment and Initial Operation of an Advanced Solar Simulator

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Jefferies, Kent S.; Mason, Lee S.

    1996-01-01

    A solar simulator utilizing nine 30-kW xenon arc lamps was built to provide radiant power for testing a solar dynamic space power system in a thermal vacuum environment. The advanced solar simulator achieved the following values specific to the solar dynamic system: (1) a subtense angle of 1 deg; (2) the ability to vary solar simulator intensity up to 1.7 kW/sq m; (3) a beam diameter of 4.8 m; and (4) uniformity of illumination on the order of +/-10%. The flexibility of the solar simulator design allows for other potential uses of the facility.

  17. Hydrocode modeling of advanced debris shield designs

    NASA Astrophysics Data System (ADS)

    Kerr, J. H.; Christiansen, E. L.; Crews, J. L.

    1996-05-01

    The NASA Johnson Space Center (JSC) Hypervelocity Impact Test Facility (HIT-F) has developed several low mass, high performance shielding concepts to protect spacecraft from orbital debris and meteoroid impact. Development testing requires shield concept validation in the impact velocity regime from <1 km/s to ˜14.5 km/s. Current two-stage light gas gun testing limits maximum impact velocities to 8 km/s; therefore, Sandia National Laboratories and Southwest Research Institute have developed advanced launchers capable of accelerating non-spherical shaped masses to ˜15 km/s. Since the shape of the impactor influences final rear wall damage, hydrocodes are employed to evaluate the so called shape effect at velocities greater than 8 km/s. A series of 14 hypervelocity impact simulations were conducted using the CTH hydrocode. Simulations modeled spherical aluminum (Al) and Al flat plate projectiles of various masses impacting double bumper all Al Whipple shields (DB). Experimental results at ˜7 km/s are compared with simulation and ballistic limit curves are constructed for the DB Whipple shield in the velocity regime greater than 7 km/s. Comments are also made on the shape effect mass ratio for spherical and flat plate projectiles.

  18. Mission lifecycle modeling and simulation

    Microsoft Academic Search

    Meemong Lee; Richard J. Weidner; Wenwen Lu

    2000-01-01

    Mission synthesis and simulation research at JPL addresses mission model taxonomy, progressive lifecycle representation, model-based design, and simulation-in-the-loop design. The Virtual Mission (VM) project integrates the research activities and implements a virtual mission lifecycle to enable a globally optimal mission. The VM is composed of three interacting modeling and simulation layers: a mission model architecture layer, a mission system simulation

  19. A survey of Existing V&V, UQ and M&S Data and Knowledge Bases in Support of the Nuclear Energy - Knowledge base for Advanced Modeling and Simulation (NE-KAMS)

    SciTech Connect

    Hyung Lee; Rich Johnson, Ph.D.; Kimberlyn C. Moussesau

    2011-12-01

    The Nuclear Energy - Knowledge base for Advanced Modeling and Simulation (NE-KAMS) is being developed at the Idaho National Laboratory in conjunction with Bettis Laboratory, Sandia National Laboratories, Argonne National Laboratory, Oak Ridge National Laboratory, Utah State University and others. The objective of this consortium is to establish a comprehensive knowledge base to provide Verification and Validation (V&V) and Uncertainty Quantification (UQ) and other resources for advanced modeling and simulation (M&S) in nuclear reactor design and analysis. NE-KAMS will become a valuable resource for the nuclear industry, the national laboratories, the U.S. NRC and the public to help ensure the safe operation of existing and future nuclear reactors. A survey and evaluation of the state-of-the-art of existing V&V and M&S databases, including the Department of Energy and commercial databases, has been performed to ensure that the NE-KAMS effort will not be duplicating existing resources and capabilities and to assess the scope of the effort required to develop and implement NE-KAMS. The survey and evaluation have indeed highlighted the unique set of value-added functionality and services that NE-KAMS will provide to its users. Additionally, the survey has helped develop a better understanding of the architecture and functionality of these data and knowledge bases that can be used to leverage the development of NE-KAMS.

  20. Delay modeling in logic simulation

    SciTech Connect

    Acken, J. M.; Goldstein, L. H.

    1980-01-01

    As digital integrated circuit size and complexity increases, the need for accurate and efficient computer simulation increases. Logic simulators such as SALOGS (SAndia LOGic Simulator), which utilize transition states in addition to the normal stable states, provide more accurate analysis than is possible with traditional logic simulators. Furthermore, the computational complexity of this analysis is far lower than that of circuit simulation such as SPICE. An eight-value logic simulation environment allows the use of accurate delay models that incorporate both element response and transition times. Thus, timing simulation with an accuracy approaching that of circuit simulation can be accomplished with an efficiency comparable to that of logic simulation. 4 figures.

  1. Refined photolysis rates for advanced air quality modeling systems

    SciTech Connect

    Roselle, S.J.; Schere, K.L.; Pleim, J.E. [National Oceanic and Atmospheric Administration, Research Triangle Park, NC (United States); Hanna, A.F.; Jang, J.C.C. [MCNC-North Carolina Supercomputing Center, Research Triangle Park, NC (United States); Lu, Y. [Environmental Protection Agency, Research Triangle Park, NC (United States)

    1996-12-31

    Accurate modeling of photochemistry is critical and fundamental to reducing the uncertainty in air quality model predictions. Almost all chemical reactions in the atmosphere are initiated by the photodissociation of a number of trace gases. A direct measure of this photodissociation is the photolysis rate. Many current air quality models use crude approximations to calculate the photolysis rates with little consideration of variations in vertical profiles of temperature, ozone concentrations, aerosol concentrations, cloud parameters, and spectral surface albedo. However, more accurate estimates of photolysis rates can be produced with advanced radiative transfer modeling techniques and data measurements. A refined module is being developed to simulate the actinic flux and photolysis rates of tropospheric species for air quality and tropospheric photochemistry modeling. The module will combine advanced radiative transfer models with explicit computations of photolysis rates using detailed information on (1) prevailing atmospheric conditions during simulation episodes, (2) satellite ozone and cloud coverage data, and (3) detailed characteristics of clouds, aerosols and surface albedo.

  2. Micromechanical modeling of advanced materials

    SciTech Connect

    Silling, S.A.; Taylor, P.A.; Wise, J.L.; Furnish, M.D.

    1994-04-01

    Funded as a laboratory-directed research and development (LDRD) project, the work reported here focuses on the development of a computational methodology to determine the dynamic response of heterogeneous solids on the basis of their composition and microstructural morphology. Using the solid dynamics wavecode CTH, material response is simulated on a scale sufficiently fine to explicitly represent the material`s microstructure. Conducting {open_quotes}numerical experiments{close_quotes} on this scale, the authors explore the influence that the microstructure exerts on the material`s overall response. These results are used in the development of constitutive models that take into account the effects of microstructure without explicit representation of its features. Applying this methodology to a glass-reinforced plastic (GRP) composite, the authors examined the influence of various aspects of the composite`s microstructure on its response in a loading regime typical of impact and penetration. As a prerequisite to the microscale modeling effort, they conducted extensive materials testing on the constituents, S-2 glass and epoxy resin (UF-3283), obtaining the first Hugoniot and spall data for these materials. The results of this work are used in the development of constitutive models for GRP materials in transient-dynamics computer wavecodes.

  3. Models and Applications as Advanced Organizers

    ERIC Educational Resources Information Center

    Lesh, Richard A., Jr.; Johnson, Howard

    1976-01-01

    The effectiveness of four types of advanced organizers for a lesson on motion geometry was analyzed. The types of organizers were: (1) single application, (2) several applications, (3) single concrete model, (4) several concrete models. Results showed that advanced organizers can be effective under some conditions. (SD)

  4. Refined photolysis rates for advanced air quality modeling systems

    SciTech Connect

    Roselle, S.J.; Hanna, A.F.; Lu, Y.; Jang, J.C.C.; Schere, K.L.

    1995-12-01

    Accurate modeling of photochemistry is critical and fundamental to reducing the uncertainty in air quality model predictions. A direct measure of this photodissociation is the photolysis rate. A refined module is being developed to simulate the actinic flux and photolysis rates of tropospheric species for air quality and tropospheric photochemistry modeling. The module will combine advanced radiative transfer models with explicit computations of photolysis rates using detailed information on (1) prevailing atmospheric conditions during simulation episodes, (2) satellite ozone and cloud coverage data, and (3) detailed characteristics of clouds, aerosols and surface albedo.

  5. Advances in beryllium powder consolidation simulation

    SciTech Connect

    Reardon, B.J.

    1998-12-01

    A fuzzy logic based multiobjective genetic algorithm (GA) is introduced and the algorithm is used to optimize micromechanical densification modeling parameters for warm isopressed beryllium powder, HIPed copper powder and CIPed/sintered and HIPed tantalum powder. In addition to optimizing the main model parameters using the experimental data points as objective functions, the GA provides a quantitative measure of the sensitivity of the model to each parameter, estimates the mean particle size of the powder, and determines the smoothing factors for the transition between stage 1 and stage 2 densification. While the GA does not provide a sensitivity analysis in the strictest sense, and is highly stochastic in nature, this method is reliable and reproducible in optimizing parameters given any size data set and determining the impact on the model of slight variations in each parameter.

  6. Advanced Tsunami Numerical Simulations and Energy Considerations by use of 3D-2D Coupled Models: The October 11, 1918, Mona Passage Tsunami

    NASA Astrophysics Data System (ADS)

    López-Venegas, Alberto M.; Horrillo, Juan; Pampell-Manis, Alyssa; Huérfano, Victor; Mercado, Aurelio

    2015-06-01

    The most recent tsunami observed along the coast of the island of Puerto Rico occurred on October 11, 1918, after a magnitude 7.2 earthquake in the Mona Passage. The earthquake was responsible for initiating a tsunami that mostly affected the northwestern coast of the island. Runup values from a post-tsunami survey indicated the waves reached up to 6 m. A controversy regarding the source of the tsunami has resulted in several numerical simulations involving either fault rupture or a submarine landslide as the most probable cause of the tsunami. Here we follow up on previous simulations of the tsunami from a submarine landslide source off the western coast of Puerto Rico as initiated by the earthquake. Improvements on our previous study include: (1) higher-resolution bathymetry; (2) a 3D-2D coupled numerical model specifically developed for the tsunami; (3) use of the non-hydrostatic numerical model NEOWAVE (non-hydrostatic evolution of ocean WAVE) featuring two-way nesting capabilities; and (4) comprehensive energy analysis to determine the time of full tsunami wave development. The three-dimensional Navier-Stokes model tsunami solution using the Navier-Stokes algorithm with multiple interfaces for two fluids (water and landslide) was used to determine the initial wave characteristic generated by the submarine landslide. Use of NEOWAVE enabled us to solve for coastal inundation, wave propagation, and detailed runup. Our results were in agreement with previous work in which a submarine landslide is favored as the most probable source of the tsunami, and improvement in the resolution of the bathymetry yielded inundation of the coastal areas that compare well with values from a post-tsunami survey. Our unique energy analysis indicates that most of the wave energy is isolated in the wave generation region, particularly at depths near the landslide, and once the initial wave propagates from the generation region its energy begins to stabilize.

  7. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  8. Advanced Visualization Technology for Terascale Particle Accelerator Simulations

    E-print Network

    Ma, Kwan-Liu

    Advanced Visualization Technology for Terascale Particle Accelerator Simulations Kwan-Liu Ma £ Greg-performance computing, particle accelerators, perception, point-based rendering, scientific visualization, field lines Introduction Particle accelerators have helped enable some of the most remarkable discoveries of the 20th

  9. An advanced Monte Carlo method for the equilibration of model long-chain branched polymers with a well-defined molecular architecture: Detailed atomistic simulation of an H-shaped polyethylene melt

    NASA Astrophysics Data System (ADS)

    Karayiannis, Nikos Ch.; Giannousaki, Ageliki E.; Mavrantzas, Vlasis G.

    2003-02-01

    With few exceptions, atomistic simulation work on polymers has been limited to linear chain systems. The main reason for this is the inability of existing Monte Carlo (MC) methods to equilibrate the short- and long-length scale characteristics of nonlinear polymers without destroying their complex molecular architecture. We report here the first MC simulation of a well-defined model long-chain branched polymer, the H-shaped polyethylene melt, in full atomistic detail. The simulation has been executed with an advanced set of chain connectivity-altering moves based on the end-bridging [Pant and Theodorou, Macromolecules 28, 7224 (1995); Mavrantzas et al., Macromolecules 32, 5072 (1999)] and double-bridging [Karayiannis et al., Phys. Rev. Lett. 88, 105503 (2002); Karayiannis et al., J. Chem. Phys. 117, 5465 (2002)] algorithms. The new scheme provides excellent system equilibration at all length scales. The new method opens up the way toward the simulation of other nonlinear polymer systems where chain branching is precisely known (such as stars and combs) and the study of their unique thermodynamic and rheological properties from first principles.

  10. Advanced Simulation Capability for Environmental Management (ASCEM) Phase II Demonstration

    SciTech Connect

    Freshley, M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hubbard, S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Flach, G. [Savannah River National Lab. (SRNL), Aiken, SC (United States); Freedman, V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Agarwal, D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Andre, B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bott, Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chen, X. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faybishenko, B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gorton, I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Murray, C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moulton, D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Meyer, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rockhold, M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shoshani, A. [LBNL; Steefel, C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wainwright, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Waichler, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-09-28

    In 2009, the National Academies of Science (NAS) reviewed and validated the U.S. Department of Energy Office of Environmental Management (EM) Technology Program in its publication, Advice on the Department of Energy’s Cleanup Technology Roadmap: Gaps and Bridges. The NAS report outlined prioritization needs for the Groundwater and Soil Remediation Roadmap, concluded that contaminant behavior in the subsurface is poorly understood, and recommended further research in this area as a high priority. To address this NAS concern, the EM Office of Site Restoration began supporting the development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific approach that uses an integration of toolsets for understanding and predicting contaminant fate and transport in natural and engineered systems. The ASCEM modeling toolset is modular and open source. It is divided into three thrust areas: Multi-Process High Performance Computing (HPC), Platform and Integrated Toolsets, and Site Applications. The ASCEM toolsets will facilitate integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. During fiscal year 2012, the ASCEM project continued to make significant progress in capabilities development. Capability development occurred in both the Platform and Integrated Toolsets and Multi-Process HPC Simulator areas. The new Platform and Integrated Toolsets capabilities provide the user an interface and the tools necessary for end-to-end model development that includes conceptual model definition, data management for model input, model calibration and uncertainty analysis, and model output processing including visualization. The new HPC Simulator capabilities target increased functionality of process model representations, toolsets for interaction with the Platform, and model confidence testing and verification for quality assurance. The Platform and HPC capabilities are being tested and evaluated for EM applications through a suite of demonstrations being conducted by the Site Applications Thrust. In 2010, the Phase I Demonstration focused on testing initial ASCEM capabilities. The Phase II Demonstration, completed in September 2012, focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site Deep Vadose Zone (BC Cribs) served as an application site for an end-to-end demonstration of ASCEM capabilities on a site with relatively sparse data, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations included in this Phase II report included addressing attenuation-based remedies at the Savannah River Site F-Area, to exercise linked ASCEM components under data-dense and complex geochemical conditions, and conducting detailed simulations of a representative waste tank. This report includes descriptive examples developed by the Hanford Site Deep Vadose Zone, the SRS F-Area Attenuation-Based Remedies for the Subsurface, and the Waste Tank Performance Assessment working groups. The integrated Phase II Demonstration provides test cases to accompany distribution of the initial user release (Version 1.0) of the ASCEM software tools to a limited set of users in 2013. These test cases will be expanded with each new release, leading up to the release of a version that is qualified for regulatory applications in the 2015 time frame.

  11. Design and simulation of advanced charge recovery piezoactuator drivers

    NASA Astrophysics Data System (ADS)

    Biancuzzi, G.; Lemke, T.; Woias, P.; Ruthmann, O.; Schrag, H. J.; Vodermayer, B.; Schmid, T.; Goldschmidtboeing, F.

    2010-10-01

    The German Artificial Sphincter System project aims at the development of an implantable sphincter prosthesis driven by a piezoelectrically actuated micropump. The system has been designed to be fully implantable, i.e. the power supply is provided by a rechargeable lithium polymer battery. In order to provide sufficient battery duration and to limit battery dimensions, special effort has to be made to minimize power consumption of the whole system and, in particular, of the piezoactuator driver circuitry. Inductive charge recovery can be used to recover part of the charge stored within the actuator. We are going to present a simplified inductor-based circuit capable of voltage inversion across the actuator without the need of an additional negative voltage source. The dimension of the inductors required for such a concept is nevertheless significant. We therefore present a novel alternative concept, called direct switching, where the equivalent capacitance of the actuator is charged directly by a step-up converter and discharged by a step-down converter. We achieved superior performance compared to a simple inductor-based driver with the advantage of using small-size chip inductors. As a term of comparison, the performance of the aforementioned drivers is compared to a conventional driver that does not implement any charge recovery technique. With our design we have been able to achieve more than 50% reduction in power consumption compared to the simplest conventional driver. The new direct switching driver performs 15% better than an inductor-based driver. A novel, whole-system SPICE simulation is presented, where both the driving circuit and the piezoactuator are modeled making use of advanced nonlinear models. Such a simulation is a precious tool to design and optimize piezoactuator drivers.

  12. Advanced numerical simulation of pulsed magnets with a finite element method

    Microsoft Academic Search

    T. Peng; C. L. Gu; K. J. M. Rosseel; J. Vanacken; F. Herlach

    2005-01-01

    The performance of a 70 T pulsed magnet with internal and external reinforcement is simulated with an advanced finite element method. The discharge analysis, thermal analysis and stress analysis are calculated with the 'coupled field analysis' scheme for the ANSYS model 'voltage-fed stranded coil'. The results show that the finite element technique is a useful tool for the design of

  13. Validation of the Advanced Microphysics Prediction System (AMPS) using TRMM PR and TMI for KWAJEX simulations

    NASA Astrophysics Data System (ADS)

    Hashino, T.; Casella, D.; Mugnai, A.; Smith, E. A.; Tripoli, G. J.

    2009-12-01

    In this paper cloud microphysical variables simulated by the Advanced Microphysics Prediction System (AMPS) are validated against TRMM PR and TMI for tropical convective systems observed during KWAJEX. AMPS includes a unique ice microphysical framework called the Spectral Habit Ice Prediction System (SHIPS) to predict ice particle properties explicitly in a cloud resolving model (UW-NMS) (Hashino and Tripoli, 2007). For this study UW-NMS AMPS is set up for 2D simulation with periodic conditions over KWAJEX campaign area with synoptic forcing. In order to compare the model simulations, two instrumental simulators will be used. We will discuss the physical connections between the simulated cloud microphysical fields and microwave observations and identify pathways to improve the AMPS and the simulators.

  14. ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

    SciTech Connect

    Helmberger, D; Tromp, J; Rodgers, A

    2007-07-16

    Comprehensive test ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the noise, it becomes useful to conduct comparable analyses on neighboring events, earthquakes in this case. If these auxiliary events have accurate moments and source descriptions, we have a means of directly comparing effective source strengths. Although we will rely on modeling codes, 1D, 2D, and 3D, we will also apply a broadband calibration procedure to use longer periods (P>5s) waveform data to calibrate short-period (P between .5 to 2 Hz) and high-frequency (P between 2 to 10 Hz) as path specify station corrections from well-known regional sources. We have expanded our basic Cut-and-Paste (CAP) methodology to include not only timing shifts but also amplitude (f) corrections at recording sites. The name of this method was derived from source inversions that allow timing shifts between 'waveform segments' (or cutting the seismogram up and re-assembling) to correct for crustal variation. For convenience, we will refer to these f-dependent refinements as CAP+ for (SP) and CAP++ for still higher frequency. These methods allow the retrieval of source parameters using only P-waveforms where radiation patterns are obvious as demonstrated in this report and are well suited for explosion P-wave data. The method is easily extended to all distances because it uses Green's function although there may be some changes required in t* to adjust for offsets between local vs. teleseismic distances. In short, we use a mixture of model-dependent and empirical corrections to tackle the path effects. Although we reply on the large TriNet array as a testbed for refining methods, we will present some preliminary results on Korea and Iran.

  15. Software Requirements Specification Verifiable Fuel Cycle Simulation (VISION) Model

    SciTech Connect

    D. E. Shropshire; W. H. West

    2005-11-01

    The purpose of this Software Requirements Specification (SRS) is to define the top-level requirements for a Verifiable Fuel Cycle Simulation Model (VISION) of the Advanced Fuel Cycle (AFC). This simulation model is intended to serve a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies.

  16. Nuclear rocket simulation system for the development of advanced control

    SciTech Connect

    Walter, P.B.; Edwards, R.M.

    1994-12-31

    An integrated control and health monitoring architecture is being developed for the Pratt and Whitney XNR2000, fast spectrum, CERMET fueled nuclear rocket. To permit testing and module development of this control architecture, a dynamic simulation system for modeling nuclear rockets has been developed. This paper described the simulation system and the resulting model of the rocket.

  17. Lessons Learned From Dynamic Simulations of Advanced Fuel Cycles

    SciTech Connect

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

    2009-04-01

    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.

  18. NEAMS FPL M2 Milestone Report: Development of a UO? Grain Size Model using Multicale Modeling and Simulation

    SciTech Connect

    Michael R Tonks; Yongfeng Zhang; Xianming Bai

    2014-06-01

    This report summarizes development work funded by the Nuclear Energy Advanced Modeling Simulation program's Fuels Product Line (FPL) to develop a mechanistic model for the average grain size in UO? fuel. The model is developed using a multiscale modeling and simulation approach involving atomistic simulations, as well as mesoscale simulations using INL's MARMOT code.

  19. AFDM: An Advanced Fluid-Dynamics Model

    SciTech Connect

    Bohl, W.R.; Parker, F.R. (Los Alamos National Lab., NM (USA)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Goutagny, L. (CEA Centre d'Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Inst. de Protection et de Surete Nucleaire); Ninokata,

    1990-09-01

    AFDM, or the Advanced Fluid-Dynamics Model, is a computer code that investigates new approaches simulating the multiphase-flow fluid-dynamics aspects of severe accidents in fast reactors. The AFDM formalism starts with differential equations similar to those in the SIMMER-II code. These equations are modified to treat three velocity fields and supplemented with a variety of new models. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, on the dominant liquid, and on the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow regimes are permitted for the pool situations modeled. Virtual mass terms are included for vapor in liquid-continuous flow. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas are also modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer is generally treated using engineering correlations. Liquid-vapor phase transitions are handled with the nonequilibrium, heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. Convection is treated using a fractional-step method of time integration, including a semi-implicit pressure iteration. A higher-order differencing option is provided to control numerical diffusion. The Los Alamos SESAME equation-of-state has been implemented using densities and temperatures as the independent variables. AFDM programming has vectorized all computational loops consistent with the objective of producing an exportable code. 24 refs., 4 figs.

  20. Advanced Simulation of Coupled Earthquake and Tsunami Events

    NASA Astrophysics Data System (ADS)

    Behrens, Joern

    2013-04-01

    Tsunami-Earthquakes represent natural catastrophes threatening lives and well-being of societies in a solitary and unexpected extreme event as tragically demonstrated in Sumatra (2004), Samoa (2009), Chile (2010), or Japan (2011). Both phenomena are consequences of the complex system of interactions of tectonic stress, fracture mechanics, rock friction, rupture dynamics, fault geometry, ocean bathymetry, and coastline geometry. The ASCETE project forms an interdisciplinary research consortium that couples the most advanced simulation technologies for earthquake rupture dynamics and tsunami propagation to understand the fundamental conditions of tsunami generation. We report on the latest research results in physics-based dynamic rupture and tsunami wave propagation simulation, using unstructured and adaptive meshes with continuous and discontinuous Galerkin discretization approaches. Coupling both simulation tools - the physics-based dynamic rupture simulation and the hydrodynamic tsunami wave propagation - will give us the possibility to conduct highly realistic studies of the interaction of rupture dynamics and tsunami impact characteristics.

  1. Requirements for advanced simulation of nuclear reactor and chemicalseparation plants.

    SciTech Connect

    Palmiotti, G.; Cahalan, J.; Pfeiffer, P.; Sofu, T.; Taiwo, T.; Wei,T.; Yacout, A.; Yang, W.; Siegel, A.; Insepov, Z.; Anitescu, M.; Hovland,P.; Pereira, C.; Regalbuto, M.; Copple, J.; Willamson, M.

    2006-12-11

    This report presents requirements for advanced simulation of nuclear reactor and chemical processing plants that are of interest to the Global Nuclear Energy Partnership (GNEP) initiative. Justification for advanced simulation and some examples of grand challenges that will benefit from it are provided. An integrated software tool that has its main components, whenever possible based on first principles, is proposed as possible future approach for dealing with the complex problems linked to the simulation of nuclear reactor and chemical processing plants. The main benefits that are associated with a better integrated simulation have been identified as: a reduction of design margins, a decrease of the number of experiments in support of the design process, a shortening of the developmental design cycle, and a better understanding of the physical phenomena and the related underlying fundamental processes. For each component of the proposed integrated software tool, background information, functional requirements, current tools and approach, and proposed future approaches have been provided. Whenever possible, current uncertainties have been quoted and existing limitations have been presented. Desired target accuracies with associated benefits to the different aspects of the nuclear reactor and chemical processing plants were also given. In many cases the possible gains associated with a better simulation have been identified, quantified, and translated into economical benefits.

  2. Advanced Power Plant Modeling with Applications to an Advanced Boiling Water

    E-print Network

    Mitchell, John E.

    Advanced Power Plant Modeling with Applications to an Advanced Boiling Water Reactor and a Heat and an Advanced Boiling Water Reactor (ABWR). The continuity wave equa- tions for single and two-phase flow advanced method, are shown. These both are applied to a simplified model of the Advanced Boil- ing Water

  3. RECENT ADVANCES IN MODELLING DUCTILE RUPTURE

    Microsoft Academic Search

    A. A. Benzerga; J. Besson; A. Pineau

    A brief account of recent advances in modelling ductile rupture is given. The importance of the inhomogeneity in the distribution of cavity nucleation sites is firstly emphasized. Then some recent extensions of the Gurson model to account for non spherical void shape are presented. Finally recent progress in modelling cavity coalescence is highlighted.

  4. National Research Council Dialogue to Assess Progress on NASA's Advanced Modeling, Simulation and Analysis Capability and Systems Engineering Capability Roadmap Development

    NASA Technical Reports Server (NTRS)

    Aikins, Jan

    2005-01-01

    Contents include the following: General Background and Introduction of Capability Roadmaps. Agency Objective. Strategic Planning Transformation. Advanced Planning Organizational Roles. Public Involvement in Strategic Planning. Strategic Roadmaps and Schedule. Capability Roadmaps and Schedule. Purpose of NRC Review. Capability Roadmap Development (Progress to Date).

  5. New scene projector developments at the AMRDEC's advanced simulation center

    Microsoft Academic Search

    Daniel A. Saylor; Mark Bowden; James Buford

    2006-01-01

    The Aviation and Missile Research, Engineering, and Development Center's (AMRDEC) System Simulation and Development Directorate (SS&DD) has an extensive history of applying all types of modeling and simulation (M&S) to weapon system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation and test for many years. Key to the successful application of HWIL testing at AMRDEC has

  6. Modeling of Spacecraft Advanced Chemical Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Benfield, Michael P. J.; Belcher, Jeremy A.

    2004-01-01

    This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Project Office. Each subsystem of the model is described. Selected model results will also be shown to demonstrate the model's ability to evaluate technology changes in chemical propulsion systems.

  7. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    Glimm, James

    2008-06-24

    The three year plan for this project is to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (both Direct Numerical Simulation and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We will model 2D and 3D perturbations of planar interfaces. We will compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we will develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. We will conduct analytic studies of mix, in support of these objectives. Advanced issues, including multiple layers and reshock, will be considered.

  8. Numerical wind speed simulation model

    SciTech Connect

    Ramsdell, J.V.; Athey, G.F.; Ballinger, M.Y.

    1981-09-01

    A relatively simple stochastic model for simulating wind speed time series that can be used as an alternative to time series from representative locations is described in this report. The model incorporates systematic seasonal variation of the mean wind, its standard deviation, and the correlation speeds. It also incorporates systematic diurnal variation of the mean speed and standard deviation. To demonstrate the model capabilities, simulations were made using model parameters derived from data collected at the Hanford Meteorology Station, and results of analysis of simulated and actual data were compared.

  9. Advances in theoretical models of network science

    Microsoft Academic Search

    Jin-Qing Fang; Qiao Bi; Yong Li

    2007-01-01

    In this review article, we will summarize the main advances in network science investigated by the CIAE Group of Complex Network\\u000a in this field. Several theoretical models of network science were proposed and their topological and dynamical properties\\u000a are reviewed and compared with the other models. Our models mainly include a harmonious unifying hybrid preferential model,\\u000a a large unifying hybrid

  10. Vol. 63 No. 8 JOM 59www.tms.org/jom.html Research SummaryAdvanced Fuel Performance: Modeling and Simulation

    E-print Network

    Motta, Arthur T.

    to waterside corrosion (defined here as uniform corrosion by coolant water, as opposed to inner-diameter stress cor- rosion cracking or to localized forms of corrosion such as nodular corro- sion) originates from and Simulation Waterside Corrosion in Zirconium Alloys Arthur T. Motta How would you... ...describe the overall

  11. Advanced Modeling Environments Daniel Dolk

    E-print Network

    Kimbrough, Steven Orla

    of system software for managing them. In the case of databases, database management systems are mature quality are available and heavily used by organizations. This is not the case for model manage- ment research in model management and decision support systems and related fields. With this as background

  12. Advanced simulation of hydroelectric transient process with Comsol/Simulink

    NASA Astrophysics Data System (ADS)

    Li, L.; Yang, J. D.

    2010-08-01

    In the study of hydroelectric system, the research of its transient process and the improvement of its simulation accuracy are restricted mainly by the precision mismatch among the hydraulic and power system models. Simulink provides a very rich control and automation model library system, thus electrical and mechanical conditioning control systems can be accurately simulated. However, it can only solve time but spatial integral problem. Due to that cause, the hydraulic system model often needs to be simplified in course of the simulation of hydroelectric transient process. Comsol, a partial differential equation (PDEs)-based multi-physics finite element analysis software, can precisely simulate the hydraulic system model. Being developed in the Matlab environment, it also can seamlessly integrate with Simulink. In this paper, based on the individual component model, an integral hydraulic-mechanical-electric system model is established by implementing Comsol code into the Simulink S-Function. This model helps to study the interaction between the hydraulic system and the electric system, and analyze the transients of a hydro plant. Meanwhile the calculation results are compared and analyzed with the general simulation system only by using Simulink.

  13. Advanced visualization technology for terascale particle accelerator simulations

    Microsoft Academic Search

    Kwan-Liu Ma; Gregory L. Schussman; Brett Wilson; Kwok Ko; Ji Qiang; Robert Ryne

    2002-01-01

    This paper presents two new hardware-assisted rendering techniques developed for interactive visualization of the terascale data generated from numerical modeling of next-generation accelerator designs. The first technique, based on a hybrid rendering approach, makes possible interactive exploration of large-scale particle data from particle beam dynamics modeling. The second technique, based on a compact texture-enhanced representation, exploits the advanced features of

  14. Advanced Models for Aeroelastic Analysis of Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Mahajan, Aparajit

    1996-01-01

    This report describes an integrated, multidisciplinary simulation capability for aeroelastic analysis and optimization of advanced propulsion systems. This research is intended to improve engine development, acquisition, and maintenance costs. One of the proposed simulations is aeroelasticity of blades, cowls, and struts in an ultra-high bypass fan. These ducted fans are expected to have significant performance, fuel, and noise improvements over existing engines. An interface program was written to use modal information from COBSTAN and NASTRAN blade models in aeroelastic analysis with a single rotation ducted fan aerodynamic code.

  15. Automatic modelling of reaction systems using genetic algorithms and its application to chemical vapour deposition processes: advanced utilizations of simulators for chemical systems

    Microsoft Academic Search

    Takahiro Takahashi; Kimito Funatsu; Yoshinori Ema

    2005-01-01

    The identification of appropriate reaction models is very helpful for developing chemical vapour deposition (CVD) processes. We introduced novel algorithms to analyse experimental data from CVD processes and identify reaction models automatically using genetic algorithms (GAs). The reaction models, which consist of various deposition species and gas-phase and surface reactions, were determined both quantitatively and qualitatively, based on chemical kinetics.

  16. Advanced turbulence models for turbomachinery

    NASA Technical Reports Server (NTRS)

    Hadid, Ali H.; Decroix, Michele E.; Sindir, Munir M.

    1993-01-01

    Development and assessment of the single-time-scale k-epsilon turbulence model with different near-wall treatments and the multi-scale turbulence model for rotating flows are presented. These turbulence models are coded as self contained module decks that can be interfaced with a number of CFD main flow solvers. For each model, a stand-alone module deck with its own formulation, discretization scheme, solver and boundary condition implementations is presented. These satellite decks will take as input (from a main flow solver) the velocity field, grid, boundary condition specifications and will deliver turbulent quantities as output. These modules were tested as separate entities and, although many logical and programming problems were overcome, only wider use and further testing can render the modules sufficiently 'fool proof'.

  17. Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova

    SciTech Connect

    James Glimm

    2009-06-04

    The three year plan for this project was to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (Direct Numerical Simulation (DNS), Large Eddy Simulations (LES), full two fluid simulations and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We model 2D and 3D perturbations of planar or circular interfaces. We compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. Multiple layers and reshock are considered here.

  18. Automatic programming of simulation models

    NASA Technical Reports Server (NTRS)

    Schroer, Bernard J.; Tseng, Fan T.; Zhang, Shou X.; Dwan, Wen S.

    1988-01-01

    The objective of automatic programming is to improve the overall environment for describing the program. This improved environment is realized by a reduction in the amount of detail that the programmer needs to know and is exposed to. Furthermore, this improved environment is achieved by a specification language that is more natural to the user's problem domain and to the user's way of thinking and looking at the problem. The goal of this research is to apply the concepts of automatic programming (AP) to modeling discrete event simulation system. Specific emphasis is on the design and development of simulation tools to assist the modeler define or construct a model of the system and to then automatically write the corresponding simulation code in the target simulation language, GPSS/PC. A related goal is to evaluate the feasibility of various languages for constructing automatic programming simulation tools.

  19. Modeling & Simulation Data Analysis and Modeling & Simulation for the

    E-print Network

    and detection, data analysis and modeling form the core of the chemical-sciences contribution to the Science space using a finite-volume technique. The code uses implicit time advancement, except for the advective capabilities in a number of disciplines. Written in the "developer friendly" Java language, it enables computer

  20. Incorporation of RAM techniques into simulation modeling

    NASA Astrophysics Data System (ADS)

    Nelson, S. C., Jr.; Haire, M. J.; Schryver, J. C.

    1995-01-01

    This work concludes that reliability, availability, and maintainability (RAM) analytical techniques can be incorporated into computer network simulation modeling to yield an important new analytical tool. This paper describes the incorporation of failure and repair information into network simulation to build a stochastic computer model to represent the RAM Performance of two vehicles being developed for the US Army: The Advanced Field Artillery System (AFAS) and the Future Armored Resupply Vehicle (FARV). The AFAS is the US Army's next generation self-propelled cannon artillery system. The FARV is a resupply vehicle for the AFAS. Both vehicles utilize automation technologies to improve the operational performance of the vehicles and reduce manpower. The network simulation model used in this work is task based. The model programmed in this application requirements a typical battle mission and the failures and repairs that occur during that battle. Each task that the FARV performs--upload, travel to the AFAS, refuel, perform tactical/survivability moves, return to logistic resupply, etc.--is modeled. Such a model reproduces a model reproduces operational phenomena (e.g., failures and repairs) that are likely to occur in actual performance. Simulation tasks are modeled as discrete chronological steps; after the completion of each task decisions are programmed that determine the next path to be followed. The result is a complex logic diagram or network. The network simulation model is developed within a hierarchy of vehicle systems, subsystems, and equipment and includes failure management subnetworks. RAM information and other performance measures are collected which have impact on design requirements. Design changes are evaluated through 'what if' questions, sensitivity studies, and battle scenario changes.

  1. Incorporation of RAM techniques into simulation modeling

    SciTech Connect

    Nelson, S.C. Jr.; Haire, M.J.; Schryver, J.C.

    1995-07-01

    This work concludes that reliability, availability, and maintainability (RAM) analytical techniques can be incorporated into computer network simulation modeling to yield an important new analytical tool. This paper describes the incorporation of failure and repair information into network simulation to build a stochastic computer model represents the RAM Performance of two vehicles being developed for the US Army: The Advanced Field Artillery System (AFAS) and the Future Armored Resupply Vehicle (FARV). The AFAS is the US Army`s next generation self-propelled cannon artillery system. The FARV is a resupply vehicle for the AFAS. Both vehicles utilize automation technologies to improve the operational performance of the vehicles and reduce manpower. The network simulation model used in this work is task based. The model programmed in this application requirements a typical battle mission and the failures and repairs that occur during that battle. Each task that the FARV performs--upload, travel to the AFAS, refuel, perform tactical/survivability moves, return to logistic resupply, etc.--is modeled. Such a model reproduces a model reproduces operational phenomena (e.g., failures and repairs) that are likely to occur in actual performance. Simulation tasks are modeled as discrete chronological steps; after the completion of each task decisions are programmed that determine the next path to be followed. The result is a complex logic diagram or network. The network simulation model is developed within a hierarchy of vehicle systems, subsystems, and equipment and includes failure management subnetworks. RAM information and other performance measures are collected which have impact on design requirements. Design changes are evaluated through ``what if`` questions, sensitivity studies, and battle scenario changes.

  2. Chain models in computer simulation

    Microsoft Academic Search

    R. Egli; N. F. Stewart

    2004-01-01

    This paper presents an extension of a previously-described framework for the specification and manipulation of models of systems. The original framework and its extension include a convenient application programming interface (API), and this paper describes examples of the use of this API in the context of graphical simulation. These examples include the simulation of objects whose definition involves torques, and

  3. Recent advances of strong-strong beam-beam simulation

    SciTech Connect

    Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.; Fischer, Wolfram; Ohmi,Kazuhito

    2004-09-15

    In this paper, we report on recent advances in strong-strong beam-beam simulation. Numerical methods used in the calculation of the beam-beam forces are reviewed. A new computational method to solve the Poisson equation on nonuniform grid is presented. This method reduces the computational cost by a half compared with the standard FFT based method on uniform grid. It is also more accurate than the standard method for a colliding beam with low transverse aspect ratio. In applications, we present the study of coherent modes with multi-bunch, multi-collision beam-beam interactions at RHIC. We also present the strong-strong simulation of the luminosity evolution at KEKB with and without finite crossing angle.

  4. Model Standards Advance the Profession

    ERIC Educational Resources Information Center

    Journal of Staff Development, 2011

    2011-01-01

    Leadership by teachers is essential to serving the needs of students, schools, and the teaching profession. To that end, the Teacher Leadership Exploratory Consortium has developed Teacher Leader Model Standards to codify, promote, and support teacher leadership as a vehicle to transform schools for the needs of the 21st century. The Teacher…

  5. A Review on Recent Advances in the Numerical Simulation for Coalbed-Methane-Recovery Process

    Microsoft Academic Search

    Xiaorong Wei; Guoxiong Wang; Paul Massarotto; Sue Golding; Victor Rudolph

    2007-01-01

    The recent advances in numerical simulation for primary coalbed methane (CBM) recovery and enhanced coalbed-methane recovery (ECBMR) processes are reviewed, primarily focusing on the progress that has occurred since the late 1980s. Two major issues regarding the numerical modeling will be discussed in this review: first, multicomponent gas transport in in-situ bulk coal and, second, changes of coal properties during

  6. Using LabVIEWTM for advanced nonlinear optoelectronic device simulations in high-speed optical communications

    Microsoft Academic Search

    R. Gutiérrez-Castrejón; M. Duelk

    2006-01-01

    We present an advanced and comprehensive semiconductor optical amplifier model to analyze the propagation and amplification of 10 to, in principle, 1280 Gb\\/s ultra-short optical pulse sequences. Through appropriate transformation, the partial differential propagation-rate equation problem is numerically solved in a two-dimensional grid of fine resolution. The corresponding simulator, entirely programmed in the graphical language LabVIEW, is compared to an

  7. SIMULATION MODELLING OF BUSINESS PROCESSES

    Microsoft Academic Search

    Ray J. Paul; Vlatka Hlupic; George M. Giaglis

    Increasingly, organisations need to adapt to new conditions and competitive pressures. Various change management approaches such as business process re- engineering have been developed to meet this perceived need. This paper investigates the potential of simulation modelling for modelling business processes. After a discussion on business processes related issues, an overview of business process modelling methods is presented. The usability

  8. Recent advances in crop growth modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop simulation models and model-based decision support systems are increasingly used to assist agricultural research and development. The systems approach and modelling tools have been linked down to scales of functional genomics and up to regional scales of natural resource management. Although cr...

  9. Progress in modeling and simulation.

    PubMed

    Kindler, E

    1998-01-01

    For the modeling of systems, the computers are more and more used while the other "media" (including the human intellect) carrying the models are abandoned. For the modeling of knowledges, i.e. of more or less general concepts (possibly used to model systems composed of instances of such concepts), the object-oriented programming is nowadays widely used. For the modeling of processes existing and developing in the time, computer simulation is used, the results of which are often presented by means of animation (graphical pictures moving and changing in time). Unfortunately, the object-oriented programming tools are commonly not designed to be of a great use for simulation while the programming tools for simulation do not enable their users to apply the advantages of the object-oriented programming. Nevertheless, there are exclusions enabling to use general concepts represented at a computer, for constructing simulation models and for their easy modification. They are described in the present paper, together with true definitions of modeling, simulation and object-oriented programming (including cases that do not satisfy the definitions but are dangerous to introduce misunderstanding), an outline of their applications and of their further development. In relation to the fact that computing systems are being introduced to be control components into a large spectrum of (technological, social and biological) systems, the attention is oriented to models of systems containing modeling components. PMID:10803299

  10. Harmonic Balance Optimization of Terahertz Schottky Diode Multipliers Using an Advanced Device Model

    Microsoft Academic Search

    E. Schlecht; G. Chattopadhyay; A. Maestrini; D. Pukala; J. Gill; I. Mehdi

    2002-01-01

    Substantial progress has been made recently in the advancement of solid state terahertz sources using chains of Schottky diode frequency multipliers. The multiplier diodes are often simulated using a simple Schottky junction model plus a series resistance, &, because of the model's simplicity and ease of use in commercial harmonic balance simulators. The DC series resistance value is useable for

  11. HARMONIC BALANCE OPTIMIZATION OF TERAHERTZ SCHOTTKY DIODE MULTIPLIERS USING AN ADVANCED DEVICE MODEL

    Microsoft Academic Search

    E. Schlecht; G. Chattopadhyay; A. Maestrini; D. Pukala; J. Gill; I. Mehdi

    2001-01-01

    Substantial progress has been made recently in the advancement of solid state terahertz sources using chains of Schottky diode frequency multipliers. The multiplier diodes are often simulated using a simple Schottky junction model plus a series resistance, RS, because of the model's simplicity and ease of use in commercial harmonic balance simulators. The DC series resistance value is useable for

  12. Advances in scientific balloon thermal modeling

    NASA Astrophysics Data System (ADS)

    Bohaboj, T.; Cathey, H.

    The National Aeronautics and Space Administration's Balloon Program Office has long acknowledged that the accurate modeling of balloon performance and flight prediction is dependant on how well the balloon is thermally modeled. This ongoing effort is focused on developing accurate balloon thermal models that can be used to quickly predict balloon temperatures and balloon performance. The ability to model parametric changes is also a driver for this effort. This paper will present the most recent advances made in this area. This research effort continues to utilize the ``Thermal Desktop'' addition to AUTO CAD for the modeling. Recent advances have been made by using this analytical tool. A number of analyses have been completed to test the applicability of this tool to the problem with very positive results. Progressively detailed models have been developed to explore the capabilities of the tool as well as to provide guidance in model formulation. A number of parametric studies have been completed. These studies have varied the shape of the structure, material properties, environmental inputs, and model geometry. These studies have concentrated on spherical ``proxy models'' for the initial development stages and then to transition to the natural shaped zero pressure and super pressure balloons. An assessment of required model resolution has also been determined. Model solutions have been cross checked with known solutions via hand calculations. The comparison of these cases will also be presented. One goal is to develop analysis guidelines and an approach for modeling balloons for both simple first order estimates and detailed full models. This paper presents the step by step advances made as part of this effort, capabilities, limitations, and the lessons learned. Also presented are the plans for further thermal modeling work.

  13. Co-Simulation for Advanced Process Design and Optimization

    SciTech Connect

    Stephen E. Zitney

    2009-01-01

    Meeting the increasing demand for clean, affordable, and secure energy is arguably the most important challenge facing the world today. Fossil fuels can play a central role in a portfolio of carbon-neutral energy options provided CO{sub 2} emissions can be dramatically reduced by capturing CO{sub 2} and storing it safely and effectively. Fossil energy industry faces the challenge of meeting aggressive design goals for next-generation power plants with CCS. Process designs will involve large, highly-integrated, and multipurpose systems with advanced equipment items with complex geometries and multiphysics. APECS is enabling software to facilitate effective integration, solution, and analysis of high-fidelity process/equipment (CFD) co-simulations. APECS helps to optimize fluid flow and related phenomena that impact overall power plant performance. APECS offers many advanced capabilities including ROMs, design optimization, parallel execution, stochastic analysis, and virtual plant co-simulations. NETL and its collaborative R&D partners are using APECS to reduce the time, cost, and technical risk of developing high-efficiency, zero-emission power plants with CCS.

  14. Graphics simulation and training aids for advanced teleoperation

    NASA Technical Reports Server (NTRS)

    Kim, Won S.; Schenker, Paul S.; Bejczy, Antal K.

    1993-01-01

    Graphics displays can be of significant aid in accomplishing a teleoperation task throughout all three phases of off-line task analysis and planning, operator training, and online operation. In the first phase, graphics displays provide substantial aid to investigate work cell layout, motion planning with collision detection and with possible redundancy resolution, and planning for camera views. In the second phase, graphics displays can serve as very useful tools for introductory training of operators before training them on actual hardware. In the third phase, graphics displays can be used for previewing planned motions and monitoring actual motions in any desired viewing angle, or, when communication time delay prevails, for providing predictive graphics overlay on the actual camera view of the remote site to show the non-time-delayed consequences of commanded motions in real time. This paper addresses potential space applications of graphics displays in all three operational phases of advanced teleoperation. Possible applications are illustrated with techniques developed and demonstrated in the Advanced Teleoperation Laboratory at JPL. The examples described include task analysis and planning of a simulated Solar Maximum Satellite Repair task, a novel force-reflecting teleoperation simulator for operator training, and preview and predictive displays for on-line operations.

  15. Advances in Modeling Exploding Bridgewire Initiation

    SciTech Connect

    Hrousis, C A; Christensen, J S

    2010-03-10

    There is great interest in applying magnetohydrodynamic (MHD) simulation techniques to the designs of electrical high explosive (HE) initiators, for the purpose of better understanding a design's sensitivities, optimizing its performance, and/or predicting its useful lifetime. Two MHD-capable LLNL codes, CALE and ALE3D, are being used to simulate the process of ohmic heating, vaporization, and plasma formation in exploding bridgewires (EBW). Initiation of the HE is simulated using Ignition & Growth reactive flow models. 1-D, 2-D and 3-D models have been constructed and studied. The models provide some intuitive explanation of the initiation process and are useful for evaluating the potential impact of identified aging mechanisms (such as the growth of intermetallic compounds or powder sintering). The end product of this work is a simulation capability for evaluating margin in proposed, modified or aged initiation system designs.

  16. Combustion modeling in advanced gas turbine systems

    SciTech Connect

    Smoot, L.D.; Hedman, P.O.; Fletcher, T.H.; Brewster, B.S.; Kramer, S.K. [Brigham Young Univ., Provo, UT (United States). Advanced Combustion Engineering Research Center

    1995-12-31

    Goal of DOE`s Advanced Turbine Systems program is to develop and commercialize ultra-high efficiency, environmentally superior, cost competitive gas turbine systems for base-load applications in utility, independent power producer, and industrial markets. Primary objective of the program here is to develop a comprehensive combustion model for advanced gas turbine combustion systems using natural gas (coal gasification or biomass fuels). The efforts included code evaluation (PCGC-3), coherent anti-Stokes Raman spectroscopy, laser Doppler anemometry, and laser-induced fluorescence.

  17. Bjt Modeling for Circuit Simulation

    Microsoft Academic Search

    Clement Keung Szeto

    1995-01-01

    Physical models for transport mechanisms important in bipolar transistors are developed, implemented in SPICE3 for DC, AC, and transient analyses, and assessed with numerical device simulations. The analytical model of quasi-saturation, or base -push-out, is derived for all current levels. Deficiencies in previous quasi-saturation models are revealed and overcome. The quasi-saturation model is based on a derivation of the current-induced-base

  18. VTI Driving Simulator: Mathematical Model of a Four-wheeled Vehicle for Simulation in Real Time. VTI Rapport 267A.

    ERIC Educational Resources Information Center

    Nordmark, Staffan

    1984-01-01

    This report contains a theoretical model for describing the motion of a passenger car. The simulation program based on this model is used in conjunction with an advanced driving simulator and run in real time. The mathematical model is complete in the sense that the dynamics of the engine, transmission and steering system is described in some…

  19. Algorithmic implementations of domain decomposition methods for the diffraction simulation of advanced photomasks

    NASA Astrophysics Data System (ADS)

    Adam, Konstantinos; Neureuther, Andrew R.

    2002-07-01

    The domain decomposition method developed in [1] is examined in more detail. This method enables rapid computer simulation of advanced photomask (alt. PSM, masks with OPC) scattering and transmission properties. Compared to 3D computer simulation, speed-up factors of approximately 400, and up to approximately 200,000 when using the look-up table approach, are possible. Combined with the spatial frequency properties of projection printing systems, it facilitates accurate computer simulation of the projected image (normalized mean square error of a typical image is only a fraction of 1%). Some esoteric accuracy issues of the method are addressed and the way to handle arbitrary, Manhattan-type mask layouts is presented. The method is shown to be valid for off-axis incidence. The cross-talk model developed in [1] is used in 3D mask simulations (2D layouts).

  20. Advanced Simulation and Computing FY08-09 Implementation Plan, Volume 2, Revision 0.5

    SciTech Connect

    Kusnezov, D; Bickel, T; McCoy, M; Hopson, J

    2007-09-13

    The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC)1 is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear-weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable Stockpile Life Extension Programs (SLEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional simulation environment while maintaining the support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: Objective 1. Robust Tools--Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements. Objective 2--Prediction through Simulation. Deliver validated physics and engineering tools to enable simulations of nuclear-weapons performances in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile. Objective 3. Balanced Operational Infrastructure--Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

  1. Advanced Simulation and Computing Fiscal Year 2011-2012 Implementation Plan, Revision 0

    SciTech Connect

    McCoy, M; Phillips, J; Hpson, J; Meisner, R

    2010-04-22

    The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering (D&E) programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional (3D) simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: Objective 1 - Robust Tools. Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements. Objective 2 - Prediction through Simulation. Deliver validated physics and engineering tools to enable simulations of nuclear weapons performance in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile. Objective 3 - Balanced Operational Infrastructure. Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

  2. Advanced Simulation and Computing FY09-FY10 Implementation Plan Volume 2, Rev. 1

    SciTech Connect

    Kissel, L

    2009-04-01

    The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: (1) Robust Tools - Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements; (2) Prediction through Simulation - Deliver validated physics and engineering tools to enable simulations of nuclear weapons performance in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile; and (3) Balanced Operational Infrastructure - Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

  3. Advanced Simulation and Computing FY09-FY10 Implementation Plan, Volume 2, Revision 0.5

    SciTech Connect

    Meisner, R; Hopson, J; Peery, J; McCoy, M

    2008-10-07

    The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC)1 is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is focused on increasing its predictive capabilities in a three-dimensional simulation environment while maintaining support to the SSP. The program continues to improve its unique tools for solving progressively more difficult stockpile problems (focused on sufficient resolution, dimensionality and scientific details); to quantify critical margins and uncertainties (QMU); and to resolve increasingly difficult analyses needed for the SSP. Moreover, ASC has restructured its business model from one that was very successful in delivering an initial capability to one that is integrated and focused on requirements-driven products that address long-standing technical questions related to enhanced predictive capability in the simulation tools. ASC must continue to meet three objectives: Objective 1. Robust Tools--Develop robust models, codes, and computational techniques to support stockpile needs such as refurbishments, SFIs, LEPs, annual assessments, and evolving future requirements. Objective 2. Prediction through Simulation--Deliver validated physics and engineering tools to enable simulations of nuclear weapons performance in a variety of operational environments and physical regimes and to enable risk-informed decisions about the performance, safety, and reliability of the stockpile. Objective 3. Balanced Operational Infrastructure--Implement a balanced computing platform acquisition strategy and operational infrastructure to meet Directed Stockpile Work (DSW) and SSP needs for capacity and high-end simulation capabilities.

  4. Acoustic test and analyses of three advanced turboprop models

    NASA Technical Reports Server (NTRS)

    Brooks, B. M.; Metzger, F. B.

    1980-01-01

    Results of acoustic tests of three 62.2 cm (24.5 inch) diameter models of the prop-fan (a small diameter, highly loaded. Multi-bladed variable pitch advanced turboprop) are presented. Results show that there is little difference in the noise produced by unswept and slightly swept designs. However, the model designed for noise reduction produces substantially less noise at test conditions simulating 0.8 Mach number cruise speed or at conditions simulating takeoff and landing. In the near field at cruise conditions the acoustically designed. In the far field at takeoff and landing conditions the acoustically designed model is 5 db quieter than unswept or slightly swept designs. Correlation between noise measurement and theoretical predictions as well as comparisons between measured and predicted acoustic pressure pulses generated by the prop-fan blades are discussed. The general characteristics of the pulses are predicted. Shadowgraph measurements were obtained which showed the location of bow and trailing waves.

  5. Maturity Model for Advancing Smart Grid Interoperability

    SciTech Connect

    Knight, Mark; Widergren, Steven E.; Mater, J.; Montgomery, Austin

    2013-10-28

    Abstract—Interoperability is about the properties of devices and systems to connect and work properly. Advancing interoperability eases integration and maintenance of the resulting interconnection. This leads to faster integration, lower labor and component costs, predictability of projects and the resulting performance, and evolutionary paths for upgrade. When specifications are shared and standardized, competition and novel solutions can bring new value streams to the community of stakeholders involved. Advancing interoperability involves reaching agreement for how things join at their interfaces. The quality of the agreements and the alignment of parties involved in the agreement present challenges that are best met with process improvement techniques. The GridWise® Architecture Council (GWAC) sponsored by the United States Department of Energy is supporting an effort to use concepts from capability maturity models used in the software industry to advance interoperability of smart grid technology. An interoperability maturity model has been drafted and experience is being gained through trials on various types of projects and community efforts. This paper describes the value and objectives of maturity models, the nature of the interoperability maturity model and how it compares with other maturity models, and experiences gained with its use.

  6. Specification of advanced safety modeling requirements (Rev. 0).

    SciTech Connect

    Fanning, T. H.; Tautges, T. J.

    2008-06-30

    The U.S. Department of Energy's Global Nuclear Energy Partnership has lead to renewed interest in liquid-metal-cooled fast reactors for the purpose of closing the nuclear fuel cycle and making more efficient use of future repository capacity. However, the U.S. has not designed or constructed a fast reactor in nearly 30 years. Accurate, high-fidelity, whole-plant dynamics safety simulations will play a crucial role by providing confidence that component and system designs will satisfy established design limits and safety margins under a wide variety of operational, design basis, and beyond design basis transient conditions. Current modeling capabilities for fast reactor safety analyses have resulted from several hundred person-years of code development effort supported by experimental validation. The broad spectrum of mechanistic and phenomenological models that have been developed represent an enormous amount of institutional knowledge that needs to be maintained. Complicating this, the existing code architectures for safety modeling evolved from programming practices of the 1970s. This has lead to monolithic applications with interdependent data models which require significant knowledge of the complexities of the entire code in order for each component to be maintained. In order to develop an advanced fast reactor safety modeling capability, the limitations of the existing code architecture must be overcome while preserving the capabilities that already exist. To accomplish this, a set of advanced safety modeling requirements is defined, based on modern programming practices, that focuses on modular development within a flexible coupling framework. An approach for integrating the existing capabilities of the SAS4A/SASSYS-1 fast reactor safety analysis code into the SHARP framework is provided in order to preserve existing capabilities while providing a smooth transition to advanced modeling capabilities. In doing this, the advanced fast reactor safety models will target leadership-class computing architectures for massively-parallel high-fidelity computations while providing continued support for rapid prototyping using modest fidelity computations on multiple-core desktop platforms.

  7. AIAA 2001-0076 AN OVERVIEW OF SIMULATION, MODELING, AND ACTIVE CONTROL OF

    E-print Network

    Dabiri, John O.

    AIAA 2001-0076 AN OVERVIEW OF SIMULATION, MODELING, AND ACTIVE CONTROL OF FLOW/ACOUSTIC RESONANCE in simulation, modeling, and con- trol of flow/acoustic resonance in flows over shallow open cavities. Many of Technology Pasadena, CA 91125 ABSTRACT An overview of some recent advances in simulation, modeling

  8. The ModelAssembler Community Modeling Environment (MA-CME): Expanded Access to Advanced Seismic Computation

    NASA Astrophysics Data System (ADS)

    Louie, J. N.; Larsen, S.

    2006-12-01

    We introduce MA-CME, an open-source environment for all PCs, Macs, and workstations that configures advanced seismic modeling runs. It is intended for use by seismologists, engineers, and students. The environment combines geologic and geotechnical data sets with gridding, modeling, and output specifications into portal packs for execution on standalone workstations, clusters, and mega-facilities such as Sun Grid. A tutorial interface helps the user scale the grid to the facilities available, from small test runs to efforts requiring major resources. The input geologic data are kept in open, editable forms to promote the creation of models for new areas, the regional extension of existing grids, and the detailing of critical features within current models. MA-CME currently drives computations with the E3D and the open-source E3D/CODE3 advanced simulation platforms; additional platforms will be added. The ability of MA-CME to configure computations at a range of scales and model complexity is intended to promote wide use of advanced seismic modeling. Wide community use may lead to breakthrough insights into how geology controls earthquake ground motion. Advanced seismic modeling platforms, coupled with increasing availability of faster clusters, have rapidly improved the realism of such deterministic simulations. Yet the number of people able to configure and successfully run simulations through complex geology has not grown. Ground-motion simulations have been published only for a few scenarios in a limited number of urban areas. MA-CME has been used to configure simulations to 2-Hz frequency for the Reno and Las Vegas, Nevada; Grenoble, France; and Wellington, New Zealand regions including multiple basins, detailed geotechnical maps, and attenuation. The package is freely available on the web. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  9. Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

  10. Advances in simulation study on organic small molecular solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Guo, Wenge; Li, Ming; Ma, Wentao; Meng, Sen

    2015-02-01

    Recently, more focuses have been put on organic semiconductors because of its advantages, such as its flexibility, ease of fabrication and potential low cost, etc. The reasons we pay highlight on small molecular photovoltaic material are its ease of purification, easy to adjust and determine structure, easy to assemble range units and get high carrier mobility, etc. Simulation study on organic small molecular solar cells before the experiment can help the researchers find relationship between the efficiency and structure parameters, properties of material, estimate the performance of the device, bring the optimization of guidance. Also, the applicability of the model used in simulation can be discussed by comparison with experimental data. This paper summaries principle, structure, progress of numerical simulation on organic small molecular solar cells.

  11. Windows Phone 7 Advanced Programming Model

    Microsoft Academic Search

    Rob Cameron

    \\u000a In this chapter, we cover additional topics related to the programming model. This is the final chapter on Silverlight for\\u000a Windows Phone 7 development, so expect to see a variety of topics, including advanced data binding, encryption services, photo\\u000a manipulation, video playback, and how to achieve deeper integration with Windows Phone for certain scenarios.

  12. A Standard Kinematic Model for Flight Simulation at NASA Ames

    NASA Technical Reports Server (NTRS)

    Mcfarland, R. E.

    1975-01-01

    A standard kinematic model for aircraft simulation exists at NASA-Ames on a variety of computer systems, one of which is used to control the flight simulator for advanced aircraft (FSAA). The derivation of the kinematic model is given and various mathematical relationships are presented as a guide. These include descriptions of standardized simulation subsystems such as the atmospheric turbulence model and the generalized six-degrees-of-freedom trim routine, as well as an introduction to the emulative batch-processing system which enables this facility to optimize its real-time environment.

  13. Modeling, Correctness & Systems Issues in Supporting Advanced Database Applications

    E-print Network

    Massachusetts at Amherst, University of

    Advanced database applications like office automation, CAD/CAM and Software Engi­ neering are characterized of Applications 2 2.1 Office Automation modeling features. Keywords: Advanced Transaction Models, Workflow Management, Cooperation, Office

  14. A review on recent advances in the numerical simulation for coalbed-methane-recovery process

    SciTech Connect

    Wei, X.R.; Wang, G.X.; Massarotto, P.; Golding, S.D.; Rudolph, V. [University of Queensland, Brisbane, Qld. (Australia)

    2007-12-15

    The recent advances in numerical simulation for primary coalbed methane (CBM) recovery and enhanced coalbed-methane recovery (ECBMR) processes are reviewed, primarily focusing on the progress that has occurred since the late 1980s. Two major issues regarding the numerical modeling will be discussed in this review: first, multicomponent gas transport in in-situ bulk coal and, second, changes of coal properties during methane (CH{sub 4}) production. For the former issues, a detailed review of more recent advances in modeling gas and water transport within a coal matrix is presented. Further, various factors influencing gas diffusion through the coal matrix will be highlighted as well, such as pore structure, concentration and pressure, and water effects. An ongoing bottleneck for evaluating total mass transport rate is developing a reasonable representation of multiscale pore space that considers coal type and rank. Moreover, few efforts have been concerned with modeling water-flow behavior in the coal matrix and its effects on CH{sub 4} production and on the exchange of carbon dioxide (CO{sub 2}) and CH{sub 4}. As for the second issue, theoretical coupled fluid-flow and geomechanical models have been proposed to describe the evolution of pore structure during CH{sub 4} production, instead of traditional empirical equations. However, there is currently no effective coupled model for engineering applications. Finally, perspectives on developing suitable simulation models for CBM production and for predicting CO{sub 2}-sequestration ECBMR are suggested.

  15. Using advanced technology repositories to accelerate simulation scenario development

    NASA Astrophysics Data System (ADS)

    Trias, Eric; Mathias, Karl S.

    2002-07-01

    One of the more difficult problems facing an analyst wishing to use a simulation is the task of collecting data and transforming it into a correctly formatted scenario. Raw data is often available from a variety of sources: multi-spectral force deployment (MSFD) documents, the electronic warfare integrated reprogramming database (EWIRDB), free text documents such as intelligence reports, pre-existing simulation scenarios, and scenarios taken from other simulations. The task of transforming this data into a usable scenario involves searching for the relevant information, followed by a manual transformation of the original format to the correct simulation format. This problem can be greatly alleviated by using a combination of three technologies: automatic parser generation, repository architectures using extensible markup language (XML), and information retrieval (IR) techniques. Automatic parser generation tools like JavaCC can automatically generate source code capable of reading data sources such as old Joint Integrated Mission Model (JIMM) or Suppressor input files. For simulations that regularly add scenario keywords to support changing needs, this can greatly reduce redevelopment time and cost for supporting tools. The objects parsed by this source can then be encapsulated in XML and stored into a repository. Using information retrieval techniques, objects can then be queried from the repository and transformed into the appropriate format for use in a scenario.

  16. Development of Computational Approaches for Simulation and Advanced Controls for Hybrid Combustion-Gasification Chemical Looping

    SciTech Connect

    Joshi, Abhinaya; Lou, Xinsheng; Neuschaefer, Carl; Chaudry, Majid; Quinn, Joseph

    2012-07-31

    This document provides the results of the project through September 2009. The Phase I project has recently been extended from September 2009 to March 2011. The project extension will begin work on Chemical Looping (CL) Prototype modeling and advanced control design exploration in preparation for a scale-up phase. The results to date include: successful development of dual loop chemical looping process models and dynamic simulation software tools, development and test of several advanced control concepts and applications for Chemical Looping transport control and investigation of several sensor concepts and establishment of two feasible sensor candidates recommended for further prototype development and controls integration. There are three sections in this summary and conclusions. Section 1 presents the project scope and objectives. Section 2 highlights the detailed accomplishments by project task area. Section 3 provides conclusions to date and recommendations for future work.

  17. Advanced nitric oxide formation modeling in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Bose, Deepak

    Nitric oxide (NO) is used as a diagnostic tool in a variety of high temperature flows. However, in order to interpret the experimental observations, a detailed kinetics simulation of NO is necessary. Thus far, the state-of-the-art simulations have been unable to adequately predict NO kinetics in these flows. It has been shown that the thermochemical models used for flow simulations fail to predict the spectral features of the ultraviolet emission from NO in hypersonic flows. This is due to the empirical nature of the current models, which are inadequate at high temperatures and strong nonequilibrium conditions. In this dissertation, an advanced modeling approach for NO formation in hypersonic flows is developed. Unlike most chemistry models currently in use, this approach is free of empirical assumptions and is valid over a wide range of conditions. The largest uncertainty in NO formation modeling is due to an inadequate treatment of the NO forming reactions: Nsb2+O-> NO+N and Osb2+N-> NO+O. A detailed quasiclassical trajectory study is done for these reactions based on ab initio data. This study provides the critically needed database of reaction attributes relevant for hypersonic flows. It is found that the thermal rate constants of these reactions are up to an order of magnitude higher than the currently used empirical rates. The obtained data show excellent agreement with the available experimental data. Furthermore, the thermal nonequilibrium is found to reduce the rate of the first reaction by up to a factor of 6. It is also shown that under nonequilibrium conditions, the NO molecules are formed with a higher vibrational energy than what the conventional simulations assume. These findings have significantly enhanced the NO formation modeling in hypersonic flows. On using this advanced model for continuum flow simulations, it is observed that the vibrational temperature of NO in the flow is higher than the predictions of the conventional simulations. This significantly improves the agreements with the experimental UV spectra at altitudes above 80 km. At lower altitudes, the uncertainties involved with other competing mechanisms cause a higher NO vibrational temperature than the one inferred from the spectra.

  18. Automatic programming of simulation models

    NASA Technical Reports Server (NTRS)

    Schroer, Bernard J.; Tseng, Fan T.; Zhang, Shou X.; Dwan, Wen S.

    1990-01-01

    The concepts of software engineering were used to improve the simulation modeling environment. Emphasis was placed on the application of an element of rapid prototyping, or automatic programming, to assist the modeler define the problem specification. Then, once the problem specification has been defined, an automatic code generator is used to write the simulation code. The following two domains were selected for evaluating the concepts of software engineering for discrete event simulation: manufacturing domain and a spacecraft countdown network sequence. The specific tasks were to: (1) define the software requirements for a graphical user interface to the Automatic Manufacturing Programming System (AMPS) system; (2) develop a graphical user interface for AMPS; and (3) compare the AMPS graphical interface with the AMPS interactive user interface.

  19. Measurement and modeling of advanced coal conversion processes

    SciTech Connect

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G. (Advanced Fuel Research, Inc., East Hartford, CT (USA)); Smoot, L.D.; Brewster, B.S. (Brigham Young Univ., Provo, UT (USA))

    1990-01-01

    The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This technology is important to reduce the technical and economic risks inherent in utilizing coal, a feedstock whose variable and often unexpected behavior presents a significant challenge. This program will merge significant advances made at Advanced Fuel Research, Inc. (AFR) in measuring and quantitatively describing the mechanisms in coal conversion behavior, with technology being developed at Brigham Young University (BYU) in comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors. The foundation to describe coal-specific conversion behavior is AFR's Functional Group (FG) and Devolatilization, Vaporization, and Crosslinking (DVC) models, developed under previous and on-going METC sponsored programs. These models have demonstrated the capability to describe the time dependent evolution of individual gas species, and the amount and characteristics of tar and char. The combined FG-DVC model will be integrated with BYU's comprehensive two-dimensional reactor model, PCGC-2, which is currently the most widely used reactor simulation for combustion or gasification. Success in this program will be a major step in improving in predictive capabilities for coal conversion processes including: demonstrated accuracy and reliability and a generalized first principles'' treatment of coals based on readily obtained composition data. The progress during the fifteenth quarterly of the program is presented. 56 refs., 41 figs., 5 tabs.

  20. BRITE II characterization and application to a new advanced flight motion simulator

    NASA Astrophysics Data System (ADS)

    Beasley, David B.; Saylor, Daniel A.; Buford, James A., Jr.

    2003-09-01

    Hardware-in-the-loop testing has, for many years, been an integral part of the modeling and simulation efforts at the U.S. Army Aviation and Missile Command"s (AMCOM) Aviation and Missile Research, Engineering, and Development Center (AMRDEC). AMCOM"s history includes the development, characterization, and implementation of several unique technologies for the creation of synthetic environments in the visible and infrared regions and AMCOM has continued significant efforts in these areas. Recently, AMCOM has been testing and characterizing a new state-of-the-art resistor array projector and advanced flight motion simulator (FMS). This paper describes recent test and integration activities of the Honeywell BRITE II emitter array and its integration into an infrared scene projector (IRSP) compatible with a new Carco Flight Motion Simulator (FMS).

  1. A numerical investigation on the efficiency of range extending systems using Advanced Vehicle Simulator

    NASA Astrophysics Data System (ADS)

    Varnhagen, Scott; Same, Adam; Remillard, Jesse; Park, Jae Wan

    2011-03-01

    Series plug-in hybrid electric vehicles of varying engine configuration and battery capacity are modeled using Advanced Vehicle Simulator (ADVISOR). The performance of these vehicles is analyzed on the bases of energy consumption and greenhouse gas emissions on the tank-to-wheel and well-to-wheel paths. Both city and highway driving conditions are considered during the simulation. When simulated on the well-to-wheel path, it is shown that the range extender with a Wankel rotary engine consumes less energy and emits fewer greenhouse gases compared to the other systems with reciprocating engines during many driving cycles. The rotary engine has a higher power-to-weight ratio and lower noise, vibration and harshness compared to conventional reciprocating engines, although performs less efficiently. The benefits of a Wankel engine make it an attractive option for use as a range extender in a plug-in hybrid electric vehicle.

  2. Theory, modeling and simulation: Annual report 1993

    SciTech Connect

    Dunning, T.H. Jr.; Garrett, B.C.

    1994-07-01

    Developing the knowledge base needed to address the environmental restoration issues of the US Department of Energy requires a fundamental understanding of molecules and their interactions in insolation and in liquids, on surfaces, and at interfaces. To meet these needs, the PNL has established the Environmental and Molecular Sciences Laboratory (EMSL) and will soon begin construction of a new, collaborative research facility devoted to advancing the understanding of environmental molecular science. Research in the Theory, Modeling, and Simulation program (TMS), which is one of seven research directorates in the EMSL, will play a critical role in understanding molecular processes important in restoring DOE`s research, development and production sites, including understanding the migration and reactions of contaminants in soils and groundwater, the development of separation process for isolation of pollutants, the development of improved materials for waste storage, understanding the enzymatic reactions involved in the biodegradation of contaminants, and understanding the interaction of hazardous chemicals with living organisms. The research objectives of the TMS program are to apply available techniques to study fundamental molecular processes involved in natural and contaminated systems; to extend current techniques to treat molecular systems of future importance and to develop techniques for addressing problems that are computationally intractable at present; to apply molecular modeling techniques to simulate molecular processes occurring in the multispecies, multiphase systems characteristic of natural and polluted environments; and to extend current molecular modeling techniques to treat complex molecular systems and to improve the reliability and accuracy of such simulations. The program contains three research activities: Molecular Theory/Modeling, Solid State Theory, and Biomolecular Modeling/Simulation. Extended abstracts are presented for 89 studies.

  3. Simulation for Supporting Scale-Up of a Fluidized Bed Reactor for Advanced Water Oxidation

    PubMed Central

    Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

    2014-01-01

    Simulation of fluidized bed reactor (FBR) was accomplished for treating wastewater using Fenton reaction, which is an advanced oxidation process (AOP). The simulation was performed to determine characteristics of FBR performance, concentration profile of the contaminants, and various prominent hydrodynamic properties (e.g., Reynolds number, velocity, and pressure) in the reactor. Simulation was implemented for 2.8?L working volume using hydrodynamic correlations, continuous equation, and simplified kinetic information for phenols degradation as a model. The simulation shows that, by using Fe3+ and Fe2+ mixtures as catalyst, TOC degradation up to 45% was achieved for contaminant range of 40–90?mg/L within 60?min. The concentration profiles and hydrodynamic characteristics were also generated. A subsequent scale-up study was also conducted using similitude method. The analysis shows that up to 10?L working volume, the models developed are applicable. The study proves that, using appropriate modeling and simulation, data can be predicted for designing and operating FBR for wastewater treatment. PMID:25309949

  4. Economic Analysis. Computer Simulation Models.

    ERIC Educational Resources Information Center

    Sterling Inst., Washington, DC. Educational Technology Center.

    A multimedia course in economic analysis was developed and used in conjunction with the United States Naval Academy. (See ED 043 790 and ED 043 791 for final reports of the project evaluation and development model.) This volume of the text discusses the simulation of behavioral relationships among variable elements in an economy and presents…

  5. Photovoltaic array performance simulation models

    Microsoft Academic Search

    D. F. Menicucci

    1985-01-01

    The experience of the solar industry confirms that despite recent cost reductions the profitability of photovoltaic (PV) systems is often marginal and the configuration and sizing of a system is a critical problem for the design engineer. Construction and evaluation of experimental systems are expensive and seldom justifiable. A mathematical model or computer simulation program is a desirable alternative, provided

  6. Advances in modeling of biomolecular interactions1

    Microsoft Academic Search

    Cong-zhong CAI; Ze-rong LI; Wan-lu WANG; Yu-zong CHEN

    Modeling of molecular interactions is increasingly used in life science research and biotechnology development. Examples are computer aided drug design, prediction of protein interactions with other molecules, and simulation of networks of biomolecules in a particular process in human body. This article reviews recent progress in the related fields and provides a brief overview on the methods used in molecular

  7. Simulation Model Driven Engineering for Manufacturing Cell

    E-print Network

    Paris-Sud XI, Université de

    Simulation Model Driven Engineering for Manufacturing Cell Hironori Hibino1 , Toshihiro Inukai2 Abstract. In our research, the simulation model driven engineering for manufacturing cell (SMDE on the simulation model and to extend the range of control applications and simulation applications using the PC

  8. Advanced virtual energy simulation training and research: IGCC with CO2 capture power plant

    Microsoft Academic Search

    S. Zitney; E. Liese; P. Mahapatra; D. Bhattacharyya; G. Provost

    2011-01-01

    In this presentation, we highlight the deployment of a real-time dynamic simulator of an integrated gasification combined cycle (IGCC) power plant with CO capture at the Department of Energy's (DOE) National Energy Technology Laboratory's (NETL) Advanced Virtual Energy Simulation Training and Research (AVESTARTM) Center. The Center was established as part of the DOE's accelerating initiative to advance new clean coal

  9. Advancements in HWIL simulation at the U.S. Army Aviation and Missile Command

    NASA Astrophysics Data System (ADS)

    Buford, James A., Jr.; Jolly, Alexander C.; Mobley, Scott B.

    1999-07-01

    This paper describes the Advanced Simulation Center (ASC) role, recaps the past year, describes the hardware-in-the- loop (HWIL) components and advancements, and outlines the path-ahead for the ASC in terms of both missile and complete system HWIL simulations and test with a focus on the imaging infrared systems.

  10. Requirements for Advanced Simulation of Nuclear Reactor and Chemical Separation Plants

    E-print Network

    Anitescu, Mihai

    Requirements for Advanced Simulation of Nuclear Reactor and Chemical Separation Plants ANL-AFCI-168 of Nuclear Reactor and Chemical Separation Plants ANL-AFCI-168 by G. Palmiotti, J. Cahalan, P. Pfeiffer, T;2 ANL-AFCI-168 Requirements for Advanced Simulation of Nuclear Reactor and Chemical Separation Plants G

  11. ADVANCED VISUALIZATION OF ENGINE SIMULATION DATA USING TEXTURE SYNTHESIS AND TOPOLOGICAL ANALYSIS

    E-print Network

    Chen, Guoning

    ADVANCED VISUALIZATION OF ENGINE SIMULATION DATA USING TEXTURE SYNTHESIS AND TOPOLOGICAL ANALYSIS Figure 1: Idealized in-cylinder flow through a diesel engine (left) and a gas engine (right). ADVANCED VISUALIZATION OF ENGINE SIMULATION DATA USING TEXTURE SYNTHESIS AND TOPOLOGICAL ANALYSIS Guoning Chen(1), Robert

  12. Modeling and Simulation for Safeguards

    SciTech Connect

    Swinhoe, Martyn T. [Los Alamos National Laboratory

    2012-07-26

    The purpose of this talk is to give an overview of the role of modeling and simulation in Safeguards R&D and introduce you to (some of) the tools used. Some definitions are: (1) Modeling - the representation, often mathematical, of a process, concept, or operation of a system, often implemented by a computer program; (2) Simulation - the representation of the behavior or characteristics of one system through the use of another system, especially a computer program designed for the purpose; and (3) Safeguards - the timely detection of diversion of significant quantities of nuclear material. The role of modeling and simulation are: (1) Calculate amounts of material (plant modeling); (2) Calculate signatures of nuclear material etc. (source terms); and (3) Detector performance (radiation transport and detection). Plant modeling software (e.g. FACSIM) gives the flows and amount of material stored at all parts of the process. In safeguards this allow us to calculate the expected uncertainty of the mass and evaluate the expected MUF. We can determine the measurement accuracy required to achieve a certain performance.

  13. Multiscale Stochastic Simulation and Modeling

    SciTech Connect

    James Glimm; Xiaolin Li

    2006-01-10

    Acceleration driven instabilities of fluid mixing layers include the classical cases of Rayleigh-Taylor instability, driven by a steady acceleration and Richtmyer-Meshkov instability, driven by an impulsive acceleration. Our program starts with high resolution methods of numerical simulation of two (or more) distinct fluids, continues with analytic analysis of these solutions, and the derivation of averaged equations. A striking achievement has been the systematic agreement we obtained between simulation and experiment by using a high resolution numerical method and improved physical modeling, with surface tension. Our study is accompanies by analysis using stochastic modeling and averaged equations for the multiphase problem. We have quantified the error and uncertainty using statistical modeling methods.

  14. VISION: Verifiable Fuel Cycle Simulation Model

    SciTech Connect

    Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

    2009-04-01

    The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

  15. VISION: Verifiable Fuel Cycle Simulation Model

    SciTech Connect

    Jacob Jacobson; A. M. Yacout; Gretchen Matthern; Steven Piet; David Shropshire; Tyler Schweitzer

    2010-11-01

    The nuclear fuel cycle consists of a set of complex components that work together in unison. In order to support the nuclear renaissance, it is necessary to understand the impacts of changes and timing of events in any part of the fuel cycle system. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing, and changes in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model components and some examples of how to use VISION.

  16. Advances in aerothermal modeling for TMT

    NASA Astrophysics Data System (ADS)

    Vogiatzis, Konstantinos

    2008-07-01

    The performance requirements of the Thirty Meter Telescope (TMT) dictate, among others, a thorough understanding of the flow field inside and around the observatory. Mirror and dome seeing as well as dynamic wind loading on the optics, telescope structure and enclosure constitute significant sources of image degradation. A summary of the current status of Computational Fluid Dynamics (CFD) simulations for TMT is presented, with special attention given to the choice of thermal boundary conditions. Detailed simulations of the mirror support assemblies determine the direction of heat flow from important heat sources and provide feedback to the design. They also provide estimates of the heat transfer coefficients for the solid thermal models. A transient radiation model has also been developed for the enclosure and telescope surfaces in order to estimate the heat flux exchange with the air volume. It also provides estimates of the effective emissivity for the solid thermal models. Finally, a complete model of the observatory on a candidate summit is used to calculate air velocity, pressure and temperature for a matrix of given telescope orientations and enclosure configurations. Calculated wind velocity spectra above M1 and around M2 as well as the wind force on the enclosure are used as inputs in the TMT integrated dynamic model. The temperature and flux output of the aforementioned thermal models are used as input surface boundary conditions in the CFD model. Generated records of temperature variations inside the air volume of the optical paths are fed into the TMT thermal seeing model.

  17. Theory, Modeling and Simulation: Research progress report 1994--1995

    Microsoft Academic Search

    B. C. Garrett; D. A. Dixon; T. H. Dunning

    1997-01-01

    The Pacific Northwest National Laboratory (PNNL) has established the Environmental Molecular Sciences Laboratory (EMSL). In April 1994, construction began on the new EMSL, a collaborative research facility devoted to advancing the understanding of environmental molecular science. Research in the Theory, Modeling, and Simulation (TM and S) program will play a critical role in understanding molecular processes important in restoring DOE`s

  18. Assessment of Molecular Modeling & Simulation

    SciTech Connect

    None

    2002-01-03

    This report reviews the development and applications of molecular and materials modeling in Europe and Japan in comparison to those in the United States. Topics covered include computational quantum chemistry, molecular simulations by molecular dynamics and Monte Carlo methods, mesoscale modeling of material domains, molecular-structure/macroscale property correlations like QSARs and QSPRs, and related information technologies like informatics and special-purpose molecular-modeling computers. The panel's findings include the following: The United States leads this field in many scientific areas. However, Canada has particular strengths in DFT methods and homogeneous catalysis; Europe in heterogeneous catalysis, mesoscale, and materials modeling; and Japan in materials modeling and special-purpose computing. Major government-industry initiatives are underway in Europe and Japan, notably in multi-scale materials modeling and in development of chemistry-capable ab-initio molecular dynamics codes.

  19. Advancing Cyberinfrastructure to support high resolution water resources modeling

    NASA Astrophysics Data System (ADS)

    Tarboton, D. G.; Ogden, F. L.; Jones, N.; Horsburgh, J. S.

    2012-12-01

    Addressing the problem of how the availability and quality of water resources at large scales are sensitive to climate variability, watershed alterations and management activities requires computational resources that combine data from multiple sources and support integrated modeling. Related cyberinfrastructure challenges include: 1) how can we best structure data and computer models to address this scientific problem through the use of high-performance and data-intensive computing, and 2) how can we do this in a way that discipline scientists without extensive computational and algorithmic knowledge and experience can take advantage of advances in cyberinfrastructure? This presentation will describe a new system called CI-WATER that is being developed to address these challenges and advance high resolution water resources modeling in the Western U.S. We are building on existing tools that enable collaboration to develop model and data interfaces that link integrated system models running within an HPC environment to multiple data sources. Our goal is to enhance the use of computational simulation and data-intensive modeling to better understand water resources. Addressing water resource problems in the Western U.S. requires simulation of natural and engineered systems, as well as representation of legal (water rights) and institutional constraints alongside the representation of physical processes. We are establishing data services to represent the engineered infrastructure and legal and institutional systems in a way that they can be used with high resolution multi-physics watershed modeling at high spatial resolution. These services will enable incorporation of location-specific information on water management infrastructure and systems into the assessment of regional water availability in the face of growing demands, uncertain future meteorological forcings, and existing prior-appropriations water rights. This presentation will discuss the informatics challenges involved with data management and easy-to-use access to high performance computing being tackled in this project.

  20. Mission simulation as an approach to develop requirements for automation in Advanced Life Support Systems.

    PubMed

    Erickson, J D; Eckelkamp, R E; Barta, D J; Dragg, J

    1996-01-01

    This paper examines mission simulation as an approach to develop requirements for automation and robotics for Advanced Life Support Systems (ALSS). The focus is on requirements and applications for command and control, control and monitoring, situation assessment and response, diagnosis and recovery, adaptive planning and scheduling, and other automation applications in addition to mechanized equipment and robotics applications to reduce the excessive human labor requirements to operate and maintain an ALSS. Based on principles of systems engineering, an approach is proposed to assess requirements for automation and robotics using mission simulation tools. First, the story of a simulated mission is defined in terms of processes with attendant types of resources needed, including options for use of automation and robotic systems. Next, systems dynamics models are used in simulation to reveal the implications for selected resource allocation schemes in terms of resources required to complete operational tasks. The simulations not only help establish ALSS design criteria, but also may offer guidance to ALSS research efforts by identifying gaps in knowledge about procedures and/or biophysical processes. Simulations of a planned one-year mission with 4 crewmembers in a Human Rated Test Facility are presented as an approach to evaluation of mission feasibility and definition of automation and robotics requirements. PMID:11538963

  1. An efficient time advancing strategy for energy-preserving simulations

    NASA Astrophysics Data System (ADS)

    Capuano, F.; Coppola, G.; de Luca, L.

    2015-08-01

    Energy-conserving numerical methods are widely employed within the broad area of convection-dominated systems. Semi-discrete conservation of energy is usually obtained by adopting the so-called skew-symmetric splitting of the non-linear convective term, defined as a suitable average of the divergence and advective forms. Although generally allowing global conservation of kinetic energy, it has the drawback of being roughly twice as expensive as standard divergence or advective forms alone. In this paper, a general theoretical framework has been developed to derive an efficient time-advancement strategy in the context of explicit Runge-Kutta schemes. The novel technique retains the conservation properties of skew-symmetric-based discretizations at a reduced computational cost. It is found that optimal energy conservation can be achieved by properly constructed Runge-Kutta methods in which only divergence and advective forms for the convective term are used. As a consequence, a considerable improvement in computational efficiency over existing practices is achieved. The overall procedure has proved to be able to produce new schemes with a specified order of accuracy on both solution and energy. The effectiveness of the method as well as the asymptotic behavior of the schemes is demonstrated by numerical simulation of Burgers' equation.

  2. Upgrading and expanding capabilities in the advanced IRCM assessment model

    NASA Astrophysics Data System (ADS)

    Kerrick, Alan D.; Forrai, David P.; Samadi, Steven S.; Maier, James

    1998-08-01

    The Air Force Research Laboratory develops the Advanced IR Countermeasures Assessment Model (AIAM), an in-house analysis tool for the National Air Intelligence Center (NAIC). AIAM allows NAIC analysts to predict the most effective countermeasure response by a foreign aircraft when engaged by IR missiles. This paper discusses enhancements to AIAM. These enhancements include the addition of IRCM decoys with lift and thrust forces and IRCMs with large spatial extent. A model is added which represents the IR emission form aircraft engines as an extended plume in addition to a point source. A Flare Toolkit is included, allowing the analyst to create a custom flare based on whatever information is available for use in the engagement simulation. A model for the trajectory followed by an IRCM attached to a flexible tether is added.

  3. Plant model generation for PLC simulation

    Microsoft Academic Search

    Hyeong-Tae Park; Jong-Geun Kwak; Gi-Nam Wang; Sang C. Park

    2010-01-01

    This paper reports an automated procedure for constructing a plant model for PLC simulation. Since PLC programs contain only the control logic without information on the plant model, it is necessary to build the corresponding plant model to perform the simulation. Conventionally, a plant model for PLC simulation has been constructed manually, which requires much effort and in-depth knowledge of

  4. Verification, Validation and Credibility Assessment of a Computational Model of the Advanced Resistive Exercise Device (ARED)

    NASA Technical Reports Server (NTRS)

    Werner, C. R.; Humphreys, B. T.; Mulugeta, L.

    2014-01-01

    The Advanced Resistive Exercise Device (ARED) is the resistive exercise device used by astronauts on the International Space Station (ISS) to mitigate bone loss and muscle atrophy due to extended exposure to microgravity (micro g). The Digital Astronaut Project (DAP) has developed a multi-body dynamics model of biomechanics models for use in spaceflight exercise physiology research and operations. In an effort to advance model maturity and credibility of the ARED model, the DAP performed verification, validation and credibility (VV and C) assessment of the analyses of the model in accordance to NASA-STD-7009 'Standards for Models and Simulations'.

  5. Simulating spin models on GPU

    NASA Astrophysics Data System (ADS)

    Weigel, Martin

    2011-09-01

    Over the last couple of years it has been realized that the vast computational power of graphics processing units (GPUs) could be harvested for purposes other than the video game industry. This power, which at least nominally exceeds that of current CPUs by large factors, results from the relative simplicity of the GPU architectures as compared to CPUs, combined with a large number of parallel processing units on a single chip. To benefit from this setup for general computing purposes, the problems at hand need to be prepared in a way to profit from the inherent parallelism and hierarchical structure of memory accesses. In this contribution I discuss the performance potential for simulating spin models, such as the Ising model, on GPU as compared to conventional simulations on CPU.

  6. A National Strategy for Advancing Climate Modeling

    SciTech Connect

    Dunlea, Edward; Elfring, Chris

    2012-12-04

    Climate models are the foundation for understanding and projecting climate and climate-related changes and are thus critical tools for supporting climate-related decision making. This study developed a holistic strategy for improving the nationâ??s capability to accurately simulate climate and related Earth system changes on decadal to centennial timescales. The committeeâ??s report is a high level analysis, providing a strategic framework to guide progress in the nationâ??s climate modeling enterprise over the next 10-20 years. This study was supported by DOE, NSF, NASA, NOAA, and the intelligence community.

  7. AFDM: An Advanced Fluid-Dynamics Model

    SciTech Connect

    Wilhelm, D.

    1990-09-01

    This volume describes the Advanced Fluid-Dynamics Model (AFDM) for topologies, flow regimes, and interfacial areas. The objective of these models is to provide values for the interfacial areas between all components existing in a computational cell. The interfacial areas are then used to evaluate the mass, energy, and momentum transfer between the components. A new approach has been undertaken in the development of a model to convect the interfacial areas of the discontinuous velocity fields in the three-velocity-field environment of AFDM. These interfacial areas are called convectible surface areas. The continuous and discontinuous components are chosen using volume fraction and levitation criteria. This establishes so-called topologies for which the convectible surface areas can be determined. These areas are functions of space and time. Solid particulates that are limited to being discontinuous within the bulk fluid are assumed to have a constant size. The convectible surface areas are subdivided to model contacts between two discontinuous components or discontinuous components and the structure. The models have been written for the flow inside of large pools. Therefore, the structure is tracked only as a boundary to the fluid volume without having a direct influence on velocity or volume fraction distribution by means of flow regimes or boundary layer models. 17 refs., 7 tabs., 18 figs.

  8. LLNL Scientists Use NERSC to Advance Global Aerosol Simulations

    SciTech Connect

    Bergmann, D J; Chuang, C; Rotman, D

    2004-10-13

    While ''greenhouse gases'' have been the focus of climate change research for a number of years, DOE's ''Aerosol Initiative'' is now examining how aerosols (small particles of approximately micron size) affect the climate on both a global and regional scale. Scientists in the Atmospheric Science Division at Lawrence Livermore National Laboratory (LLNL) are using NERSC's IBM supercomputer and LLNL's IMPACT (atmospheric chemistry) model to perform simulations showing the historic effects of sulfur aerosols at a finer spatial resolution than ever done before. Simulations were carried out for five decades, from the 1950s through the 1990s. The results clearly show the effects of the changing global pattern of sulfur emissions. Whereas in 1950 the United States emitted 41 percent of the world's sulfur aerosols, this figure had dropped to 15 percent by 1990, due to conservation and anti-pollution policies. By contrast, the fraction of total sulfur emissions of European origin has only dropped by a factor of 2 and the Asian emission fraction jumped six fold during the same time, from 7 percent in 1950 to 44 percent in 1990. Under a special allocation of computing time provided by the Office of Science INCITE (Innovative and Novel Computational Impact on Theory and Experiment) program, Dan Bergmann, working with a team of LLNL scientists including Cathy Chuang, Philip Cameron-Smith, and Bala Govindasamy, was able to carry out a large number of calculations during the past month, making the aerosol project one of the largest users of NERSC resources. The applications ran on 128 and 256 processors. The objective was to assess the effects of anthropogenic (man-made) sulfate aerosols. The IMPACT model calculates the rate at which SO{sub 2} (a gas emitted by industrial activity) is oxidized and forms particles known as sulfate aerosols. These particles have a short lifespan in the atmosphere, often washing out in about a week. This means that their effects on climate tend to be more regional, occurring near the area where the SO{sub 2} is emitted. To accurately study these regional effects, Bergmann needed to run the simulations at a finer horizontal resolution, as the coarser resolution (typically 300km by 300km) of other climate models are insufficient for studying changes on a regional scale. Livermore's use of CAM3, the Community Atmospheric Model which is a high-resolution climate model developed at NCAR (with collaboration from DOE), allows a 100km by 100km grid to be applied. NERSC's terascale computing capability provided the needed computational horsepower to run the application at the finer level.

  9. Advanced wellbore thermal simulator GEOTEMP2 user manual

    SciTech Connect

    Mondy, L.A.; Duda, L.E.

    1984-11-01

    GEOTEMP2 is a wellbore thermal simulator computer code designed for geothermal drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A variety of well operations can be modeled including injection, production, forward, and reverse circulation with gas or liquid, gas or liquid drilling, and two-phase steam injection and production. Well completion with several different casing sizes and cement intervals can be modeled. The code allows variables suchas flow rate to change with time enabling a realistic treatment of well operations. This user manual describes the input required to properly operate the code. Ten sample problems are included which illustrate all the code options. Complete listings of the code and the output of each sample problem are provided.

  10. Creating Simulated Microgravity Patient Models

    NASA Technical Reports Server (NTRS)

    Hurst, Victor; Doerr, Harold K.; Bacal, Kira

    2004-01-01

    The Medical Operational Support Team (MOST) has been tasked by the Space and Life Sciences Directorate (SLSD) at the NASA Johnson Space Center (JSC) to integrate medical simulation into 1) medical training for ground and flight crews and into 2) evaluations of medical procedures and equipment for the International Space Station (ISS). To do this, the MOST requires patient models that represent the physiological changes observed during spaceflight. Despite the presence of physiological data collected during spaceflight, there is no defined set of parameters that illustrate or mimic a 'space normal' patient. Methods: The MOST culled space-relevant medical literature and data from clinical studies performed in microgravity environments. The areas of focus for data collection were in the fields of cardiovascular, respiratory and renal physiology. Results: The MOST developed evidence-based patient models that mimic the physiology believed to be induced by human exposure to a microgravity environment. These models have been integrated into space-relevant scenarios using a human patient simulator and ISS medical resources. Discussion: Despite the lack of a set of physiological parameters representing 'space normal,' the MOST developed space-relevant patient models that mimic microgravity-induced changes in terrestrial physiology. These models are used in clinical scenarios that will medically train flight surgeons, biomedical flight controllers (biomedical engineers; BME) and, eventually, astronaut-crew medical officers (CMO).

  11. Advanced Modelling of Silicon Wafer Solar Cells

    NASA Astrophysics Data System (ADS)

    Peters, Marius; Fajun, Ma; Siyu, Guo; Hoex, Bram; Blaesi, Benedikt; Glunz, Stefan; Aberle, Armin; Luther, Joachim

    2012-10-01

    Modelling of solar cells today is general practice in research and widely-used in industry. Established modelling software is typically limited to one dimension and/or to small scales. Additionally, novel effects, like, e.g., the use of diffractive structures or luminescent materials, are not established. In this paper we discuss how the combination of different modelling techniques can be used to overcome these limitations. In this context two examples are presented. The first example concerns the combination of the open source simulation software PC1D with circuit modelling to investigate the effect of local shunts on the global characteristics of a silicon wafer solar cell. For the investigated example (4.5 cm2 cell area) we find that a local point shunt reduces the solar cell efficiency by 4% relative. The second example concerns the modelling of diffractive gratings for thin silicon wafer solar cells. For this purpose, we use the rigorous coupled wave analysis to simulate Sentaurus technical computer-aided design (TCAD) is combined with the rigorous coupled wave analysis, a method to solve Maxwell's equations for periodic structures. Here we show that a grating can be used to improve the absorption in a thin silicon wafer solar cell considerably.

  12. Prospects for Advanced RF Theory and Modeling

    SciTech Connect

    Batchelor, D.B.

    1999-04-12

    This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed.

  13. Advanced modeling of active control of fan noise for ultra high bypass turbofan engines

    Microsoft Academic Search

    Florence Vanel Hutcheson

    1999-01-01

    An advanced model of active control of fan noise for ultra high bypass turbofan engines has been developed. This model is based on a boundary integral equation method and simulates the propagation, radiation and control of the noise generated by an engine fan surrounded by a duct of finite length and cylindrical shape, placed in a uniform flow. Control sources,

  14. Modeling and Simulation: PowerBoosting Productivity with Simulation.

    ERIC Educational Resources Information Center

    Riley, Suzanne

    Minnesota high school students and teachers are learning the technology of simulation and integrating it into business and industrial technology courses. Modeling and simulation is the science of using software to construct a system within an organization and then running simulations of proposed changes to assess results before funds are spent. In…

  15. A Social Diffusion Model with an Application on Election Simulation

    PubMed Central

    Wang, Fu-Min; Hung, San-Chuan; Kung, Perng-Hwa; Lin, Shou-De

    2014-01-01

    Issues about opinion diffusion have been studied for decades. It has so far no empirical approach to model the interflow and formation of crowd's opinion in elections due to two reasons. First, unlike the spread of information or flu, individuals have their intrinsic attitudes to election candidates in advance. Second, opinions are generally simply assumed as single values in most diffusion models. However, in this case, an opinion should represent preference toward multiple candidates. Previously done models thus may not intuitively interpret such scenario. This work is to design a diffusion model which is capable of managing the aforementioned scenario. To demonstrate the usefulness of our model, we simulate the diffusion on the network built based on a publicly available bibliography dataset. We compare the proposed model with other well-known models such as independent cascade. It turns out that our model consistently outperforms other models. We additionally investigate electoral issues with our model simulator. PMID:24995351

  16. RIGOROUS MODELING AND SIMULATION OF MECHATRONIC SYSTEMS

    E-print Network

    Taylor, James H.

    RIGOROUS MODELING AND SIMULATION OF MECHATRONIC SYSTEMS James H. Taylor Professor Emeritus, Systems on mechatronic systems. Emphasis is placed on rigorous techniques and selecting the most appropriate method mentioned above for mechatronic systems. Key Words: Mechatronic systems, modeling, simulation, numerical

  17. Advanced Concepts for Underwater Acoustic Channel Modeling

    NASA Astrophysics Data System (ADS)

    Etter, P. C.; Haas, C. H.; Ramani, D. V.

    2014-12-01

    This paper examines nearshore underwater-acoustic channel modeling concepts and compares channel-state information requirements against existing modeling capabilities. This process defines a subset of candidate acoustic models suitable for simulating signal propagation in underwater communications. Underwater-acoustic communications find many practical applications in coastal oceanography, and networking is the enabling technology for these applications. Such networks can be formed by establishing two-way acoustic links between autonomous underwater vehicles and moored oceanographic sensors. These networks can be connected to a surface unit for further data transfer to ships, satellites, or shore stations via a radio-frequency link. This configuration establishes an interactive environment in which researchers can extract real-time data from multiple, but distant, underwater instruments. After evaluating the obtained data, control messages can be sent back to individual instruments to adapt the networks to changing situations. Underwater networks can also be used to increase the operating ranges of autonomous underwater vehicles by hopping the control and data messages through networks that cover large areas. A model of the ocean medium between acoustic sources and receivers is called a channel model. In an oceanic channel, characteristics of the acoustic signals change as they travel from transmitters to receivers. These characteristics depend upon the acoustic frequency, the distances between sources and receivers, the paths followed by the signals, and the prevailing ocean environment in the vicinity of the paths. Properties of the received signals can be derived from those of the transmitted signals using these channel models. This study concludes that ray-theory models are best suited to the simulation of acoustic signal propagation in oceanic channels and identifies 33 such models that are eligible candidates.

  18. Simulation modeling with artificial reality technology (SMART): an integration of virtual reality and simulation modeling

    Microsoft Academic Search

    Hank Grant; Chuen-Ki Lai

    1998-01-01

    Simulation Modeling with Artificial Reality Technology (SMART) is a simulation modeling tool that provides a virtual reality interface for building graphical simulation models. The simulation models, comprised of nodes and arcs, are constructed in three dimensions. As the user builds a model, he may immerse himself in it using virtual reality hardware and software tools and take advantage of the

  19. Comparing Aerodynamic Models for Numerical Simulation of

    E-print Network

    Peraire, Jaime

    Comparing Aerodynamic Models for Numerical Simulation of Dynamics and Control of Aircraft and simulation of aircraft, yet other aerodynamics models exist that can provide more accurate results derivatives and other low fidelity models are frequently used in the design and flight simulation of aircraft

  20. Advance finite element modeling of rotor blade aeroelasticity

    NASA Technical Reports Server (NTRS)

    Straub, F. K.; Sangha, K. B.; Panda, B.

    1994-01-01

    An advanced beam finite element has been developed for modeling rotor blade dynamics and aeroelasticity. This element is part of the Element Library of the Second Generation Comprehensive Helicopter Analysis System (2GCHAS). The element allows modeling of arbitrary rotor systems, including bearingless rotors. It accounts for moderately large elastic deflections, anisotropic properties, large frame motion for maneuver simulation, and allows for variable order shape functions. The effects of gravity, mechanically applied and aerodynamic loads are included. All kinematic quantities required to compute airloads are provided. In this paper, the fundamental assumptions and derivation of the element matrices are presented. Numerical results are shown to verify the formulation and illustrate several features of the element.

  1. 2009 US-Japan Workshop on Advanced Simulation Methods in Plasma Physics Plasma Particle Simulation with Adaptive Mesh Refinement Technique

    E-print Network

    Ito, Atsushi

    2009 US-Japan Workshop on Advanced Simulation Methods in Plasma Physics Plasma Particle Simulation-5292, Japan 2 Kobe University, Kobe 657-8501, Japan 3 Kyoto University, Uji 611-0011, Japan 4 Japan Aerospace Exploration Agency, Sagamihara 229-8510, Japan 5 Japan Science and Technology Agency, CREST, Kawaguchi 332

  2. A critical appraisal of model simulations

    SciTech Connect

    MacCracken, M.C.

    1990-02-01

    The complexity of the climate system and the absence of definitive analogs to the evolving climatic situation force use of theoretical models to project the future climatic influence of the relatively rapid and on-going increase in the atmospheric concentrations of CO{sub 2} and other trace gases. The most comprehensive of the available climate models are known as General Circulation Models (GCMs). These models represent what are believed to be the most important components of atmosphere, ocean, and cryosphere system relevant to determining the potential for an enhanced greenhouse effect. Two types of studies are performed to study the potential consequences of the increasing concentrations of greenhouse gases. In the first, the gas concentration (usually CO{sub 2}) is arbitrarily and instantaneously increased and the model is run until a new equilibrium climate is reached, the difference between the perturbed and control results being a measure of the sensitivity of the climate to the imposed perturbation. In the second type of simulation, the gas concentration is slowly increased as time advances. 1 tab.

  3. Photovoltaic array performance simulation models

    SciTech Connect

    Menicucci, D.F.

    1985-01-01

    The experience of the solar industry confirms that despite recent cost reductions the profitability of photovoltaic (PV) systems is often marginal and the configuration and sizing of a system is a critical problem for the design engineer. Construction and evaluation of experimental systems are expensive and seldom justifiable. A mathematical model or computer simulation program is a desirable alternative, provided reliable results can be obtained. Sandia National Laboratories, Albuquerque (SNLA), has been studying PV system modeling techniques in an effort to develop an effective tool to be used by engineers and architects in the design of cost-effective PV systems. This paper reviews two of the sources of error found in previous PV modeling programs, presents the remedies developed to correct these errors, and describes a new program that incorporates these improvements.

  4. Model Validation with Hybrid Dynamic Simulation

    SciTech Connect

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

    2006-06-18

    Abstract—Model 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.

  5. Advanced virtual energy simulation training and research: IGCC with CO2 capture power plant

    SciTech Connect

    Zitney, S.; Liese, E.; Mahapatra, P.; Bhattacharyya, D.; Provost, G.

    2011-01-01

    In this presentation, we highlight the deployment of a real-time dynamic simulator of an integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture at the Department of Energy's (DOE) National Energy Technology Laboratory's (NETL) Advanced Virtual Energy Simulation Training and Research (AVESTARTM) Center. The Center was established as part of the DOE's accelerating initiative to advance new clean coal technology for power generation. IGCC systems are an attractive technology option, generating low-cost electricity by converting coal and/or other fuels into a clean synthesis gas mixture in a process that is efficient and environmentally superior to conventional power plants. The IGCC dynamic simulator builds on, and reaches beyond, conventional power plant simulators to merge, for the first time, a 'gasification with CO{sub 2} capture' process simulator with a 'combined-cycle' power simulator. Fueled with coal, petroleum coke, and/or biomass, the gasification island of the simulated IGCC plant consists of two oxygen-blown, downward-fired, entrained-flow, slagging gasifiers with radiant syngas coolers and two-stage sour shift reactors, followed by a dual-stage acid gas removal process for CO{sub 2} capture. The combined cycle island consists of two F-class gas turbines, steam turbine, and a heat recovery steam generator with three-pressure levels. The dynamic simulator can be used for normal base-load operation, as well as plant start-up and shut down. The real-time dynamic simulator also responds satisfactorily to process disturbances, feedstock blending and switchovers, fluctuations in ambient conditions, and power demand load shedding. In addition, the full-scope simulator handles a wide range of abnormal situations, including equipment malfunctions and failures, together with changes initiated through actions from plant field operators. By providing a comprehensive IGCC operator training system, the AVESTAR Center is poised to develop a workforce well-prepared to operate and control commercial-scale gasification-based power plants capable of 90% pre-combustion CO{sub 2} capture and compression, as well as low sulfur, mercury, and NOx emissions. With additional support from the NETL-Regional University Alliance (NETL-RUA), the Center will educate and train engineering students and researchers by providing hands-on 'learning by operating' experience The AVESTAR Center also offers unique collaborative R&D opportunities in high-fidelity dynamic modeling, advanced process control, real-time optimization, and virtual plant simulation. Objectives and goals are aimed at safe and effective management of power generation systems for optimal efficiency, while protecting the environment. To add another dimension of realism to the AVESTAR experience, NETL will introduce an immersive training system with innovative three-dimensional virtual reality technology. Wearing a stereoscopic headset or eyewear, trainees will enter an interactive virtual environment that will allow them to move freely throughout the simulated 3-D facility to study and learn various aspects of IGCC plant operation, control, and safety. Such combined operator and immersive training systems go beyond traditional simulation and include more realistic scenarios, improved communication, and collaboration among co-workers.

  6. [Research advance on lake ecosystem dynamic models].

    PubMed

    Liu, Yong; Guo, Huaicheng; Fan, Yingying; Wang, Lijing

    2005-06-01

    Starting with the role of system analysis in lake ecosystem research, this paper summarized the tentative procedures and softwares for studying the dynamics of lake ecosystem. There are several main stages in modeling the dynamics of lake ecosystem, namely, problems identification, mathematical formulation, computation, validation, sensitive analysis, calibration, and verification. In the modeling, selecting temporal and spatial scales is essential but complex. Since 1960s, a rapid progress has been made in modeling the dynamics of lake ecosystem, being developed from simple zero-dimension models to complex ecological-aquatic-hydrodynamic ones, among which, exergy was applied popularly as an objective function in modeling. In this paper, LakeWeb and LEEDS (Lake Eutrophication, Effect, Dose, and Sensitivity model) were analyzed as examples. In China, the development of lake ecosystem dynamic models could be traced back to 1980s, and most of them were focused on Lake Dianch, Lake Taihu, Lake Chaohu and Lake Donghu. Some softwares such as CE-QUAL-ICM, WASP, AQUATOX, PAMOLARE and CAEDYM were developed to simulate lake ecosystem dynamics, among which, CE-QUAL-ICM is more suitable for long and narrow water bodies. WASP consists of three parts, i. e., DYNHYD, EUTRO, and TOXI. AQUATOX is an ecological risk model, and the parameters are mainly calibrated in U. S. A, which has limited its further application in China. The software ECOPATH for simulating the energy flows in lakes was also described in this paper. There are still many shortages in the lake ecosystem dynamic models, e. g., the lack of sufficient monitoring data for validation, insufficient consideration of uncertainties and the role of bacteria, and inconsistent relationship with watershed changes. The uncertainties are mainly from the intrinsic uncertainties in aquatic ecosystem, in modeling, in parameters selection, and also in forecast and application. Setting up long-term monitoring and data sharing mechanism, using interpolation to make data more densely, introducing objective functions, dealing with uncertainties, and constructing watershed-lake ecosystem dynamic model could be the available ways for overcoming the shortages. PMID:16180776

  7. Simulation, Modelling and Visualisation: Toolkits for Building Simulated Worlds.

    E-print Network

    Hawick, Ken

    Simulation, Modelling and Visualisation: Toolkits for Building Simulated Worlds. D. P. Playne, A. P and particle models to support research with Cahn- Hillard Cook [2] and Ginzburg-Landau equations, artificial and in three dimensions the cells are arranged as a cube. Figure 1: 3D Field Equation Visualisation. Figure 1

  8. Advanced Simulation of Coupled Earthquake and Tsunami Events (ASCETE) - Simulation Techniques for Realistic Tsunami Process Studies

    NASA Astrophysics Data System (ADS)

    Behrens, Joern; Bader, Michael; Breuer, Alexander N.; van Dinther, Ylona; Gabriel, Alice-A.; Galvez Barron, Percy E.; Rahnema, Kaveh; Vater, Stefan; Wollherr, Stephanie

    2015-04-01

    At the End of phase 1 of the ASCETE project a simulation framework for coupled physics-based rupture generation with tsunami propagation and inundation is available. Adaptive mesh tsunami propagation and inundation by discontinuous Galerkin Runge-Kutta methods allows for accurate and conservative inundation schemes. Combined with a tree-based refinement strategy to highly optimize the code for high-performance computing architectures, a modeling tool for high fidelity tsunami simulations has been constructed. Validation results demonstrate the capacity of the software. Rupture simulation is performed by an unstructured tetrahedral discontinuous Galerking ADER discretization, which allows for accurate representation of complex geometries. The implemented code was nominated for and was selected as a finalist for the Gordon Bell award in high-performance computing. Highly realistic rupture events can be simulated with this modeling tool. The coupling of rupture induced wave activity and displacement with hydrodynamic equations still poses a major problem due to diverging time and spatial scales. Some insight from the ASCETE set-up could be gained and the presentation will focus on the coupled behavior of the simulation system. Finally, an outlook to phase 2 of the ASCETE project will be given in which further development of detailed physical processes as well as near-realistic scenario computations are planned. ASCETE is funded by the Volkswagen Foundation.

  9. Use of Advanced Meteorological Model Output for Coastal Ocean Modeling in Puget Sound

    SciTech Connect

    Yang, Zhaoqing; Khangaonkar, Tarang; Wang, Taiping

    2011-06-01

    It is a great challenge to specify meteorological forcing in estuarine and coastal circulation modeling using observed data because of the lack of complete datasets. As a result of this limitation, water temperature is often not simulated in estuarine and coastal modeling, with the assumption that density-induced currents are generally dominated by salinity gradients. However, in many situations, temperature gradients could be sufficiently large to influence the baroclinic motion. In this paper, we present an approach to simulate water temperature using outputs from advanced meteorological models. This modeling approach was applied to simulate annual variations of water temperatures of Puget Sound, a fjordal estuary in the Pacific Northwest of USA. Meteorological parameters from North American Region Re-analysis (NARR) model outputs were evaluated with comparisons to observed data at real-time meteorological stations. Model results demonstrated that NARR outputs can be used to drive coastal ocean models for realistic simulations of long-term water-temperature distributions in Puget Sound. Model results indicated that the net flux from NARR can be further improved with the additional information from real-time observations.

  10. Measurement and modeling of advanced coal conversion processes. Annual report, October 1990--September 1991

    SciTech Connect

    Solomon, P.R.; Serio, M.A.; Hamblen, D.G.; Smoot, L.D.; Brewster, B.S. [Advanced Fuel Research, Inc., East Hartford, CT (United States); [Brigham Young Univ., Provo, UT (United States)

    1991-12-31

    The overall objective of this program is the development of predictive capability for the design, scale up, simulation, control and feedstock evaluation in advanced coal conversion devices. This program will merge significant advances made in measuring and quantitatively describing the mechanisms in coal conversion behavior. Comprehensive computer codes for mechanistic modeling of entrained-bed gasification. Additional capabilities in predicting pollutant formation will be implemented and the technology will be expanded to fixed-bed reactors.

  11. Deceleration in advance in the Nagel-Schreckenberg traffic flow model

    NASA Astrophysics Data System (ADS)

    Li, Xin-Gang; Gao, Zi-You; Jia, Bin; Jiang, Rui

    2009-05-01

    Based on the Nagel-Schreckenberg model, we study the impact of deceleration in advance on the dynamics of traffic flow. In the process of deceleration in advance, the effect of reaction delay and the effect of expectation are considered respectively. The traffic flow properties are studied by analyzing the fundamental diagram, spatio-temporal patterns, distance headway distribution and car accidents. The simulation results show that reaction delay brings complex traffic flow patterns and expectation makes the serious car accidents rarely happen.

  12. MODELING AND SIMULATING HUMAN TEAMWORK BEHAVIORS 1 Modeling and Simulating Human Teamwork

    E-print Network

    MODELING AND SIMULATING HUMAN TEAMWORK BEHAVIORS 1 Modeling and Simulating Human Teamwork Behaviors #12;MODELING AND SIMULATING HUMAN TEAMWORK BEHAVIORS 2 Abstract Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork

  13. Plasma disruption modeling and simulation

    SciTech Connect

    Hassanein, A.

    1994-07-01

    Disruptions in tokamak reactors are considered a limiting factor to successful operation and a reliable design. The behavior of plasma-facing components during a disruption is critical to the overall integrity of the reactor. Erosion of plasma facing-material (PFM) surfaces due to thermal energy dump during the disruption can severely limit the lifetime of these components and thus diminish the economic feasibility of the reactor.Initially, the incident plasma particles will deposit their energy directly on the PFM surface, heating it to a very high temperature where ablation occurs. Models for plasma-material interactions have been developed and used to predict material thermal evolution during the disruption. Within a few microseconds after the start of the disruption, enough material is vaporized to intercept most of the incoming plasma particles. Models for plasma-vapor interactions are necessary to predict vapor cloud expansion and hydrodynamics. Continuous heating of the vapor cloud above the material surface by the incident plasma particles will excite, ionize, and cause vapor atoms to emit thermal radiation. Accurate models for radiation transport in the vapor are essential for calculating the net radiated flux to the material surface which determines the final erosion thickness and consequently component lifetime. A comprehensive model that takes into account various stages of plasma-material interaction has been developed and used to predict erosion rates during reactor disruption, as well during induced disruption in laboratory experiments. Differences between various simulation experiments and reactor conditions are discussed. A two-dimensional radiation transport model has been developed to particularly simulate the effect of small test samples used in laboratory disruption experiments.

  14. Off-gas Adsorption Model and Simulation - OSPREY

    SciTech Connect

    Veronica J Rutledge

    2013-10-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and REcoverY (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed.

  15. Timed Automata Lecture #15 of Advanced Model Checking

    E-print Network

    Ábrahám, Erika

    of the computation, but ­ also on the time at which the results are produced · How to model timing issues: ­ discrete-time or continuous-time? c JPK 1 #12;Advanced model checking A discrete time domain · Time has a discrete nature, i.e., time is advanced by discrete steps ­ time is modelled by naturals; actions can only happen at natural

  16. Timed Automata Lecture #15 of Advanced Model Checking

    E-print Network

    Ábrahám, Erika

    , but ­ also on the time at which the results are produced · How to model timing issues: ­ discrete-time or continuous-time? c JPK 1 #12;Advanced model checking A discrete time domain · Time has a discrete nature, i.e., time is advanced by discrete steps ­ time is modelled by naturals; actions can only happen at natural

  17. Advanced Method to Estimate Fuel Slosh Simulation Parameters

    NASA Technical Reports Server (NTRS)

    Schlee, Keith; Gangadharan, Sathya; Ristow, James; Sudermann, James; Walker, Charles; Hubert, Carl

    2005-01-01

    The nutation (wobble) of a spinning spacecraft in the presence of energy dissipation is a well-known problem in dynamics and is of particular concern for space missions. The nutation of a spacecraft spinning about its minor axis typically grows exponentially and the rate of growth is characterized by the Nutation Time Constant (NTC). For launch vehicles using spin-stabilized upper stages, fuel slosh in the spacecraft propellant tanks is usually the primary source of energy dissipation. For analytical prediction of the NTC this fuel slosh is commonly modeled using simple mechanical analogies such as pendulums or rigid rotors coupled to the spacecraft. Identifying model parameter values which adequately represent the sloshing dynamics is the most important step in obtaining an accurate NTC estimate. Analytic determination of the slosh model parameters has met with mixed success and is made even more difficult by the introduction of propellant management devices and elastomeric diaphragms. By subjecting full-sized fuel tanks with actual flight fuel loads to motion similar to that experienced in flight and measuring the forces experienced by the tanks these parameters can be determined experimentally. Currently, the identification of the model parameters is a laborious trial-and-error process in which the equations of motion for the mechanical analog are hand-derived, evaluated, and their results are compared with the experimental results. The proposed research is an effort to automate the process of identifying the parameters of the slosh model using a MATLAB/SimMechanics-based computer simulation of the experimental setup. Different parameter estimation and optimization approaches are evaluated and compared in order to arrive at a reliable and effective parameter identification process. To evaluate each parameter identification approach, a simple one-degree-of-freedom pendulum experiment is constructed and motion is induced using an electric motor. By applying the estimation approach to a simple, accurately modeled system, its effectiveness and accuracy can be evaluated. The same experimental setup can then be used with fluid-filled tanks to further evaluate the effectiveness of the process. Ultimately, the proven process can be applied to the full-sized spinning experimental setup to quickly and accurately determine the slosh model parameters for a particular spacecraft mission. Automating the parameter identification process will save time, allow more changes to be made to proposed designs, and lower the cost in the initial design stages.

  18. Modeling of Army Research Laboratory EMP simulators

    SciTech Connect

    Miletta, J.R.; Chase, R.J.; Luu, B.B. (Army Research Lab., Adelphi, MD (United States)); Williams, J.W.; Viverito, V.J. (Science Applications International Corp., Germantown, MD (United States))

    1993-12-01

    Models are required that permit the estimation of emitted field signatures from EMP simulators to design the simulator antenna structure, to establish the usable test volumes, and to estimate human exposure risk. This paper presents the capabilities and limitations of a variety of EMP simulator models useful to the Army's EMP survivability programs. Comparisons among frequency and time-domain models are provided for two powerful US Army Research Laboratory EMP simulators: AESOP (Army EMP Simulator Operations) and VEMPS II (Vertical EMP Simulator II).

  19. Some Specific CASL Requirements for Advanced Multiphase Flow Simulation of Light Water Reactors

    SciTech Connect

    R. A. Berry

    2010-11-01

    Because of the diversity of physical phenomena occuring in boiling, flashing, and bubble collapse, and of the length and time scales of LWR systems, it is imperative that the models have the following features: • Both vapor and liquid phases (and noncondensible phases, if present) must be treated as compressible. • Models must be mathematically and numerically well-posed. • The models methodology must be multi-scale. A fundamental derivation of the multiphase governing equation system, that should be used as a basis for advanced multiphase modeling in LWR coolant systems, is given in the Appendix using the ensemble averaging method. The remainder of this work focuses specifically on the compressible, well-posed, and multi-scale requirements of advanced simulation methods for these LWR coolant systems, because without these are the most fundamental aspects, without which widespread advancement cannot be claimed. Because of the expense of developing multiple special-purpose codes and the inherent inability to couple information from the multiple, separate length- and time-scales, efforts within CASL should be focused toward development of a multi-scale approaches to solve those multiphase flow problems relevant to LWR design and safety analysis. Efforts should be aimed at developing well-designed unified physical/mathematical and high-resolution numerical models for compressible, all-speed multiphase flows spanning: (1) Well-posed general mixture level (true multiphase) models for fast transient situations and safety analysis, (2) DNS (Direct Numerical Simulation)-like models to resolve interface level phenmena like flashing and boiling flows, and critical heat flux determination (necessarily including conjugate heat transfer), and (3) Multi-scale methods to resolve both (1) and (2) automatically, depending upon specified mesh resolution, and to couple different flow models (single-phase, multiphase with several velocities and pressures, multiphase with single velocity and pressure, etc.) A unified, multi-scale approach is advocated to extend the necessary foundations and build the capability to simultaneously solve the fluid dynamic interface problems (interface resolution) as well as multiphase mixtures (homogenization).

  20. Real-Time Simulation Techniques Based on the RTO.k Object Modeling

    Microsoft Academic Search

    K. H. Kim; Cuong Nguyen; Chan-mo Park

    1996-01-01

    Real-time simulation is an advanced mode of simulation in which the simulation objects are designed to show the same timing behavior that the simulation targets do. A new approach to real-time simulation which is based on the RTO.k object modeling is discussed in this paper. The RTO.k object, which is a real-time extension of the well-established object structure, is capable

  1. A modular BLSS simulation model

    NASA Technical Reports Server (NTRS)

    Rummel, John D.; Volk, Tyler

    1987-01-01

    A bioregenerative life support system (BLSS) for extraterrestrial use will be faced with coordination problems more acute than those in any ecosystem found on Earth. A related problem in BLSS design is providing an interface between the various life support processors, one that will allow for their coordination while still allowing for system expansion. A modular model is presented of a BLSS that interfaces system processors only with the material storage reservoirs, allowing those reservoirs to act as the principal buffers in the system and thus minimizing difficulties with processor coordination. The modular nature of the model allows independent development of the detailed submodels that exist within the model framework. Using this model, BLSS dynamics were investigated under normal conditions and under various failure modes. Partial and complete failures of various components, such as the waste processors or the plants themselves, drive transient responses in the model system, allowing the examination of the effectiveness of the system reservoirs as buffers. The results from simulations help to determine control strategies and BLSS design requirements. An evolved version could be used as an interactive control aid in a future BLSS.

  2. Advanced computational techniques to simulate up-to-date automotive antenna EM\\/EMC problems

    Microsoft Academic Search

    F. G. Bogdanov; R. G. Jobava; D. D. Karkashadze; P. Tsereteli; A. L. Gheonjian; E. A. Yavolovskaya; I. Oganezova

    2010-01-01

    Based on the recent enhancements of the traditional MoM, a combined set of the advanced methods, techniques and special means is proposed to provide an accurate and effective simulation of EM\\/EMC automotive antenna problems.

  3. Advancement of DOE's EnergyPlus Building Energy Simulation Payment

    SciTech Connect

    Lixing Gu; Don Shirey; Richard Raustad; Bereket Nigusse; Chandan Sharma; Linda Lawrie; Rich Strand; Curt Pedersen; Dan Fisher; Edwin Lee; Mike Witte; Jason Glazer; Chip Barnaby

    2011-03-31

    EnergyPlus{sup TM} is a new generation computer software analysis tool that has been developed, tested, and commercialized to support DOEâ??s Building Technologies (BT) Program in terms of whole-building, component, and systems R&D (http://www.energyplus.gov). It is also being used to support evaluation and decision making of zero energy building (ZEB) energy efficiency and supply technologies during new building design and existing building retrofits. The 5-year project was managed by the National Energy Technology Laboratory and was divided into 5 budget period between 2006 and 2011. During the project period, 11 versions of EnergyPlus were released. This report summarizes work performed by an EnergyPlus development team led by the University of Central Floridaâ??s Florida Solar Energy Center (UCF/FSEC). The team members consist of DHL Consulting, C. O. Pedersen Associates, University of Illinois at Urbana-Champaign, Oklahoma State University, GARD Analytics, Inc., and WrightSoft Corporation. The project tasks involved new feature development, testing and validation, user support and training, and general EnergyPlus support. The team developed 146 new features during the 5-year period to advance the EnergyPlus capabilities. Annual contributions of new features are 7 in budget period 1, 19 in period 2, 36 in period 3, 41 in period 4, and 43 in period 5, respectively. The testing and validation task focused on running test suite and publishing report, developing new IEA test suite cases, testing and validating new source code, addressing change requests, and creating and testing installation package. The user support and training task provided support for users and interface developers, and organized and taught workshops. The general support task involved upgrading StarTeam (team sharing) software and updating existing utility software. The project met the DOE objectives and completed all tasks successfully. Although the EnergyPlus software was enhanced significantly under this project, more enhancements are needed for further improvement to ensure that EnergyPlus is able to simulate the latest technologies and perform desired HAVC system operations for the development of next generation HVAC systems. Additional development will be performed under a new 5-year project managed by the National Renewable Energy Laboratory.

  4. Modelling and Simulation in Medical Imaging Book Series, Imperial College Press, UK

    E-print Network

    Ammari, Habib

    Modelling and Simulation in Medical Imaging Book Series, Imperial College Press, UK Editorial Board contributions describing advanced technologies in biomedical imaging and related mathematical problems and techniques. Innovative approaches in biomedical imaging, such as diffusion tensor imaging, multi

  5. A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL)

    NASA Technical Reports Server (NTRS)

    Carroll, Chester C.; Owen, Jeffrey E.

    1988-01-01

    A direct-execution parallel architecture for the Advanced Continuous Simulation Language (ACSL) is presented which overcomes the traditional disadvantages of simulations executed on a digital computer. The incorporation of parallel processing allows the mapping of simulations into a digital computer to be done in the same inherently parallel manner as they are currently mapped onto an analog computer. The direct-execution format maximizes the efficiency of the executed code since the need for a high level language compiler is eliminated. Resolution is greatly increased over that which is available with an analog computer without the sacrifice in execution speed normally expected with digitial computer simulations. Although this report covers all aspects of the new architecture, key emphasis is placed on the processing element configuration and the microprogramming of the ACLS constructs. The execution times for all ACLS constructs are computed using a model of a processing element based on the AMD 29000 CPU and the AMD 29027 FPU. The increase in execution speed provided by parallel processing is exemplified by comparing the derived execution times of two ACSL programs with the execution times for the same programs executed on a similar sequential architecture.

  6. On the utility of graphics cards to perform massively parallel simulation of advanced Monte Carlo methods.

    PubMed

    Lee, Anthony; Yau, Christopher; Giles, Michael B; Doucet, Arnaud; Holmes, Christopher C

    2010-12-01

    We present a case-study on the utility of graphics cards to perform massively parallel simulation of advanced Monte Carlo methods. Graphics cards, containing multiple Graphics Processing Units (GPUs), are self-contained parallel computational devices that can be housed in conventional desktop and laptop computers and can be thought of as prototypes of the next generation of many-core processors. For certain classes of population-based Monte Carlo algorithms they offer massively parallel simulation, with the added advantage over conventional distributed multi-core processors that they are cheap, easily accessible, easy to maintain, easy to code, dedicated local devices with low power consumption. On a canonical set of stochastic simulation examples including population-based Markov chain Monte Carlo methods and Sequential Monte Carlo methods, we nd speedups from 35 to 500 fold over conventional single-threaded computer code. Our findings suggest that GPUs have the potential to facilitate the growth of statistical modelling into complex data rich domains through the availability of cheap and accessible many-core computation. We believe the speedup we observe should motivate wider use of parallelizable simulation methods and greater methodological attention to their design. PMID:22003276

  7. Advances in Materials Science and Applications March. 2013, Vol. 2 Iss. 1, PP. 9-24 Discrete Element Modeling and Analysis of

    E-print Network

    Grujicic, Mica

    ) is investigated using advanced transient, non-linear dynamics, discrete-element modeling (DEM) and simulation the present work, advanced transient, non-linear dynamics, discrete-element modeling (DEM) and simulation.e. position, velocity, acceleration, force and torque) of each discrete particle in the system and its

  8. Simulation model development in information security education

    Microsoft Academic Search

    Jose M. Garrido; Tridib Bandyopadhyay

    2009-01-01

    The value of modeling and simulation for education, training, and testing in information security has been documented in several studies. In this paper, we suggest that it is important not only to include the general use of simulation in various courses of the security curriculum, but also to include the theory and development of simulation models. We describe briefly the

  9. Verification and validation of simulation models

    Microsoft Academic Search

    Jack P. C. Kleijnen

    1995-01-01

    This paper surveys verification and validation of models, especially simulation models in operations research. For verification it discusses 1) general good programming practice (such as modular programming), 2) checking intermediate simulation outputs through tracing and statistical testing per module, 3) statistical testing of final simulation outputs against analytical results, and 4) animation. For validation it discusses 1) obtaining real-worl data,

  10. Simulation-based evaluation of Advanced Traveler Information Services (ATIS)

    E-print Network

    Florian, Daniel George

    2004-01-01

    Drivers using information from an Advanced Traveler Information System (ATIS) could potentially make better travel decisions to reduce travel time and increase trip reliability, thereby benefiting both guided drivers as ...

  11. Advances in modeling wave particle interactions in the radiation belts

    NASA Astrophysics Data System (ADS)

    Shprits, Yuri

    2012-07-01

    We discuss the recent advances in simulations of the inner and outer radiation belts including radial, pitch-angle, energy, and mixed diffusio, and nno-lineaactions. Recently developed computer codes allow for qauntificaiton of the qussi-linear scattering due to day-side and night-side chorus waves, magneto-sonic waves, phasmaspheric hiss waves, EMIC and hiss waves in the regions of plumes, lightning generated whistlers, and anthropogenic whistlers. Sensitivity simulations show that the knowledge of wave spectral properties and spatial distribution of waves is crucially important for reproducing long term observations. The 3D simulations are compared to 3D reanalysis of the radiation belt fluxes that are obtained by blending the predictive model with observations from GEO, CRRES, Akebono, GPS and LANL. Recent research shows that similar processes may be responsible for acceleration and loss of energetic particles on the outer planet. Similar processes may be also important for acceleration and loss of particles on the Sun and solar wind and in other corners of the Universe.

  12. Dynamic fabric modelling and simulation using deformable models

    Microsoft Academic Search

    Hassen Hedfi; Adel Ghith; Hédi BelHadjSalah

    2011-01-01

    This paper proposes a modelling of the dynamic behaviour of textile fabrics based on a new formulation of deformable models. Deformable models such as those that were introduced by Terzopoulos in 1987 for modelling and simulation of deformable objects in computer graphics are reformulated to simulate textile woven fabrics. This investigation tends to produce simulations of textile fabrics showing the

  13. Multiple model simulation: modelling cell division and differentiation in the

    E-print Network

    Stepney, Susan

    behaviours are simulated in the modified-prostate simulation; (c) to experiment with the vari- ous formsMultiple model simulation: modelling cell division and differentiation in the prostate Alastair this approach to building a model of prostate cell division and differentiation, with each model layer

  14. User's manual for ADAM (Advanced Dynamic Airfoil Model)

    SciTech Connect

    Oler, J.W.; Strickland, J.H.; Im, B.J.

    1987-06-01

    The computer code for an advanced dynamic airfoil model (ADAM) is described. The code is capable of calculating steady or unsteady flow over two-dimensional airfoils with allowances for boundary layer separation. Specific types of airfoil motions currently installed are steady rectilinear motion, impulsively started rectilinear motion, constant rate pitching, sinusoidal pitch oscillations, sinusoidal lateral plunging, and simulated Darrieus turbine motion. Other types of airfoil motion may be analyzed through simple modifications of a single subroutine. The code has a built-in capability to generate the geometric parameters for a cylinder, the NACA four-digit series of airfoils, and a NASA NLF-0416 laminar airfoil. Other types of airfoils are easily incorporated. The code ADAM is currently in a state of development. It is theoretically consistent and complete. However, further work is needed on the numerical implementation of the method.

  15. Monte Carlo simulation of ice models

    SciTech Connect

    Barkema, G.T. [HLRZ, Forschungszentrum Juelich, 52425 Juelich (Germany)] [HLRZ, Forschungszentrum Juelich, 52425 Juelich (Germany); Newman, M.E. [Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501 (United States)] [Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501 (United States)

    1998-01-01

    We study a number of Monte Carlo algorithms for the simulation of ice models, and compare their efficiency. One of them, a cluster algorithm for the equivalent three-color model, appears to have a dynamic exponent close to zero, making it particularly useful for simulations of critical ice models. We have performed extensive simulations using our algorithms to determine a number of critical exponents for the square ice and F models. {copyright} {ital 1998} {ital The American Physical Society}

  16. RAM simulation model for SPH/RSV systems

    SciTech Connect

    Schryver, J.C.; Primm, A.H.; Nelson, S.C.

    1995-12-31

    The US Army`s Project Manager, Crusader is sponsoring the development of technologies that apply to the Self-Propelled Howitzer (SPH), formerly the Advanced Field Artillery System (AFAS), and Resupply Vehicle (RSV), formerly the Future Armored Resupply Vehicle (FARV), weapon system. Oak Ridge National Laboratory (ORNL) is currently performing developmental work in support of the SPH/PSV Crusader system. Supportive analyses of reliability, availability, and maintainability (RAM) aspects were also performed for the SPH/RSV effort. During FY 1994 and FY 1995 OPNL conducted a feasibility study to demonstrate the application of simulation modeling for RAM analysis of the Crusader system. Following completion of the feasibility study, a full-scale RAM simulation model of the Crusader system was developed for both the SPH and PSV. This report provides documentation for the simulation model as well as instructions in the proper execution and utilization of the model for the conduct of RAM analyses.

  17. Numerical simulation of an advanced energy storage system using H 2O–LiBr as working fluid, Part 2: System simulation and analysis

    Microsoft Academic Search

    S. M. Xu; C. H. Xu; L. Zhang; J. Liang; R. Du

    2007-01-01

    This paper is the second part of our study on the advanced energy storage system using H2O–LiBr as working fluid. In the first part, the system working principle has been introduced, and the system dynamic models in the operation process have also been developed. Based on the previous research, this paper focuses on the numerical simulation to investigate the system

  18. RECENT ADVANCES IN MACROMOLECULAR HYDRODYNAMIC MODELING

    PubMed Central

    Aragon, Sergio R.

    2010-01-01

    The modern implementation of the boundary element method (S.R. Aragon, J. Comput. Chem. 25(2004)1191–12055) has ushered unprecedented accuracy and precision for the solution of the Stokes equations of hydrodynamics with stick boundary conditions. This article begins by reviewing computations with the program BEST of smooth surface objects such as ellipsoids, the dumbbell, and cylinders that demonstrate that the numerical solution of the integral equation formulation of hydrodynamics yields very high precision and accuracy. When BEST is used for macromolecular computations, the limiting factor becomes the definition of the molecular hydrodynamic surface and the implied effective solvation of the molecular surface. Studies on 49 different proteins, ranging in molecular weight from 9 to over 400 kDa, have shown that a model using a 1.1 A thick hydration layer describes all protein transport properties very well for the overwhelming majority of them. In addition, this data implies that the crystal structure is an excellent representation of the average solution structure for most of them. In order to investigate the origin of a handful of significant discrepancies in some multimeric proteins (over ?20% observed in the intrinsic viscosity), the technique of Molecular Dynamics simulation (MD) has been incorporated into the research program. A preliminary study of dimeric ?-chymotrypsin using approximate implicit water MD is presented. In addition I describe the successful validation of modern protein force fields, ff03 and ff99SB, for the accurate computation of solution structure in explicit water simulation by comparison of trajectory ensemble average computed transport properties with experimental measurements. This work includes small proteins such as lysozyme, ribonuclease and ubiquitin using trajectories around 10 ns duration. We have also studied a 150 kDa flexible monoclonal IgG antibody, trastuzumab, with multiple independent trajectories encompassing over 320 ns of simulation. The close agreement within experimental error of the computed and measured properties allows us to conclude that MD does produce structures typical of those in solution, and that flexible molecules can be properly described using the method of ensemble averaging over a trajectory. We review similar work on the study of a transfer RNA molecule and DNA oligomers that demonstrate that within 3% a simple uniform hydration model 1.1 A thick provides agreement with experiment for these nucleic acids. In the case of linear oligomers, the precision can be improved close to 1% by a non-uniform hydration model that hydrates mainly in the DNA grooves, in agreement with high resolution x-ray diffraction. We conclude with a vista on planned improvements for the BEST program to decrease its memory requirements and increase its speed without sacrificing accuracy. PMID:21073955

  19. Advanced Numerical Methods and Software Approaches for Semiconductor Device Simulation

    DOE PAGESBeta

    Carey, Graham F.; Pardhanani, A. L.; Bova, S. W.

    2000-01-01

    In this article we concisely present several modern strategies that are applicable to driftdominated carrier transport in higher-order deterministic models such as the driftdiffusion, hydrodynamic, and quantum hydrodynamic systems. The approaches include extensions of “upwind” and artificial dissipation schemes, generalization of the traditional Scharfetter – Gummel approach, Petrov – Galerkin and streamline-upwind Petrov Galerkin (SUPG), “entropy” variables, transformations, least-squares mixed methods and other stabilized Galerkin schemes such as Galerkin least squares and discontinuous Galerkin schemes. The treatment is representative rather than an exhaustive review and several schemes are mentioned only briefly with appropriate reference to the literature. Some of themore »methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. We have included numerical examples from our recent research tests with some of the methods. A second aspect of the work deals with algorithms that employ unstructured grids in conjunction with adaptive refinement strategies. The full benefits of such approaches have not yet been developed in this application area and we emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, we briefly consider some aspects of software frameworks. These include dial-an-operator approaches such as that used in the industrial simulator PROPHET, and object-oriented software support such as those in the SANDIA National Laboratory framework SIERRA.« less

  20. Propulsion System Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Tai, Jimmy C. M.; McClure, Erin K.; Mavris, Dimitri N.; Burg, Cecile

    2002-01-01

    The Aerospace Systems Design Laboratory at the School of Aerospace Engineering in Georgia Institute of Technology has developed a core competency that enables propulsion technology managers to make technology investment decisions substantiated by propulsion and airframe technology system studies. This method assists the designer/manager in selecting appropriate technology concepts while accounting for the presence of risk and uncertainty as well as interactions between disciplines. This capability is incorporated into a single design simulation system that is described in this paper. This propulsion system design environment is created with a commercially available software called iSIGHT, which is a generic computational framework, and with analysis programs for engine cycle, engine flowpath, mission, and economic analyses. iSIGHT is used to integrate these analysis tools within a single computer platform and facilitate information transfer amongst the various codes. The resulting modeling and simulation (M&S) environment in conjunction with the response surface method provides the designer/decision-maker an analytical means to examine the entire design space from either a subsystem and/or system perspective. The results of this paper will enable managers to analytically play what-if games to gain insight in to the benefits (and/or degradation) of changing engine cycle design parameters. Furthermore, the propulsion design space will be explored probabilistically to show the feasibility and viability of the propulsion system integrated with a vehicle.

  1. Modeling and simulation: tools for metabolic engineering

    Microsoft Academic Search

    Wolfgang Wiechert

    2002-01-01

    Mathematical modeling is one of the key methodologies of metabolic engineering. Based on a given metabolic model different computational tools for the simulation, data evaluation, systems analysis, prediction, design and optimization of metabolic systems have been developed. The currently used metabolic modeling approaches can be subdivided into structural models, stoichiometric models, carbon flux models, stationary and nonstationary mechanistic models and

  2. Recent advances in large-eddy simulation of spray and coal combustion

    NASA Astrophysics Data System (ADS)

    Zhou, L. X.

    2013-07-01

    Large-eddy simulation (LES) is under its rapid development and is recognized as a possible second generation of CFD methods used in engineering. Spray and coal combustion is widely used in power, transportation, chemical and metallurgical, iron and steel making, aeronautical and astronautical engineering, hence LES of spray and coal two-phase combustion is particularly important for engineering application. LES of two-phase combustion attracts more and more attention; since it can give the detailed instantaneous flow and flame structures and more exact statistical results than those given by the Reynolds averaged modeling (RANS modeling). One of the key problems in LES is to develop sub-grid scale (SGS) models, including SGS stress models and combustion models. Different investigators proposed or adopted various SGS models. In this paper the present author attempts to review the advances in studies on LES of spray and coal combustion, including the studies done by the present author and his colleagues. Different SGS models adopted by different investigators are described, some of their main results are summarized, and finally some research needs are discussed.

  3. ADVANCES IN MODELING OF GROUND-SOURCE HEAT

    E-print Network

    ADVANCES IN MODELING OF GROUND-SOURCE HEAT PUMP SYSTEMS By ANDREW D. CHIASSON Bachelor of Applied 1999 #12;ii ADVANCES IN MODELING OF GROUND-SOURCE HEAT PUMP SYSTEMS Thesis Approved: Thesis Adviser..............................................................................................................1 1.1. Overview of Ground-Source Heat Pump Systems ..............................................1 1

  4. Harmonic balance optimization of terahertz Schottky diode multipliers using an advanced device model

    NASA Technical Reports Server (NTRS)

    Schlecht, E. T.; Chattopadhyay, G.; Maestrini, A.; Pukala, D.; Gill, J.; Mehdi, I.

    2002-01-01

    Substantial proress has been made recently in the advancement of solid state terahertz sources using chains of Schottky diode frequency multipliers. We have developed a harmonic balance simulator and corresponding diode model that incorporates many other factors participating in the diode behavior.

  5. A simulation of the evacuation of american citizens with an object-oriented, animated model

    Microsoft Academic Search

    Jeffrey E. Sumner; Eric A. Zahn

    1996-01-01

    This paper highlights a model developed by TASC, Inc. under contract to the Defense Advanced Research Projects Agency (DARPA). This project models and simulates an evacuation of American citizens and other important foreign nationals from a destabilized foreign country by utilizing available U.S. military resources. This project demonstrates how different evacuation plans can quickly be compared analytically through computer simulation.

  6. A simulation of the evacuation of American citizens with an object-oriented, animated model

    Microsoft Academic Search

    Jeffrey E. Sumner; Eric A. Zahn

    1996-01-01

    This paper highlights a model developed by TASC, Inc. under contract to the Defense Advanced Research Projects Agency (DARPA). This project models and simulates an evacuation of American citizens and other important foreign nationals from a destabilized foreign country by utilizing available U.S. military resources. This project demonstrates how different evacuation plans can quickly be compared analytically through computer simulation.

  7. ADVANCED SIMULATION CAPABILITY FOR ENVIRONMENTAL MANAGEMENT- CURRENT STATUS AND PHASE II DEMONSTRATION RESULTS

    SciTech Connect

    Seitz, R.

    2013-02-26

    The U.S. Department of Energy (USDOE) Office of Environmental Management (EM), Office of Soil and Groundwater, is supporting development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific tool and approach for understanding and predicting contaminant fate and transport in natural and engineered systems. The modular and open source high-performance computing tool facilitates integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. The ASCEM project continues to make significant progress in development of computer software capabilities with an emphasis on integration of capabilities in FY12. Capability development is occurring for both the Platform and Integrated Toolsets and High-Performance Computing (HPC) Multiprocess Simulator. The Platform capabilities provide the user interface and tools for end-to-end model development, starting with definition of the conceptual model, management of data for model input, model calibration and uncertainty analysis, and processing of model output, including visualization. The HPC capabilities target increased functionality of process model representations, toolsets for interaction with Platform, and verification and model confidence testing. The Platform and HPC capabilities are being tested and evaluated for EM applications in a set of demonstrations as part of Site Applications Thrust Area activities. The Phase I demonstration focusing on individual capabilities of the initial toolsets was completed in 2010. The Phase II demonstration completed in 2012 focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site deep vadose zone (BC Cribs) served as an application site for an end-to-end demonstration of capabilities, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations, addressing attenuation-based remedies at the Savannah River Site F Area and performance assessment for a representative waste tank, illustrate integration of linked ASCEM capabilities and initial integration efforts with tools from the Cementitious Barriers Partnership.

  8. ADVANCED SIMULATION CAPABILITY FOR ENVIRONMENTAL MANAGEMENT – CURRENT STATUS AND PHASE II DEMONSTRATION RESULTS

    SciTech Connect

    Seitz, Roger; Freshley, Mark D.; Dixon, Paul; Hubbard, Susan S.; Freedman, Vicky L.; Flach, Gregory P.; Faybishenko, Boris; Gorton, Ian; Finsterle, Stefan A.; Moulton, John D.; Steefel, Carl I.; Marble, Justin

    2013-06-27

    The U.S. Department of Energy (USDOE) Office of Environmental Management (EM), Office of Soil and Groundwater, is supporting development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific tool and approach for understanding and predicting contaminant fate and transport in natural and engineered systems. The modular and open source high-performance computing tool facilitates integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. The ASCEM project continues to make significant progress in development of computer software capabilities with an emphasis on integration of capabilities in FY12. Capability development is occurring for both the Platform and Integrated Toolsets and High-Performance Computing (HPC) Multiprocess Simulator. The Platform capabilities provide the user interface and tools for end-to-end model development, starting with definition of the conceptual model, management of data for model input, model calibration and uncertainty analysis, and processing of model output, including visualization. The HPC capabilities target increased functionality of process model representations, toolsets for interaction with Platform, and verification and model confidence testing. The Platform and HPC capabilities are being tested and evaluated for EM applications in a set of demonstrations as part of Site Applications Thrust Area activities. The Phase I demonstration focusing on individual capabilities of the initial toolsets was completed in 2010. The Phase II demonstration completed in 2012 focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site deep vadose zone (BC Cribs) served as an application site for an end-to-end demonstration of capabilities, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations, addressing attenuation-based remedies at the Savannah River Site F Area and performance assessment for a representative waste tank, illustrate integration of linked ASCEM capabilities and initial integration efforts with tools from the Cementitious Barriers Partnership.

  9. New simulation model of multicomponent crystal growth and inhibition.

    PubMed

    Wathen, Brent; Kuiper, Michael; Walker, Virginia; Jia, Zongchao

    2004-04-01

    We review a novel computational model for the study of crystal structures both on their own and in conjunction with inhibitor molecules. The model advances existing Monte Carlo (MC) simulation techniques by extending them from modeling 3D crystal surface patches to modeling entire 3D crystals, and by including the use of "complex" multicomponent molecules within the simulations. These advances makes it possible to incorporate the 3D shape and non-uniform surface properties of inhibitors into simulations, and to study what effect these inhibitor properties have on the growth of whole crystals containing up to tens of millions of molecules. The application of this extended MC model to the study of antifreeze proteins (AFPs) and their effects on ice formation is reported, including the success of the technique in achieving AFP-induced ice-growth inhibition with concurrent changes to ice morphology that mimic experimental results. Simulations of ice-growth inhibition suggest that the degree of inhibition afforded by an AFP is a function of its ice-binding position relative to the underlying anisotropic growth pattern of ice. This extended MC technique is applicable to other crystal and crystal-inhibitor systems, including more complex crystal systems such as clathrates. PMID:15054746

  10. An introduction to enterprise modeling and simulation

    SciTech Connect

    Ostic, J.K.; Cannon, C.E. [Los Alamos National Lab., NM (United States). Technology Modeling and Analysis Group

    1996-09-01

    As part of an ongoing effort to continuously improve productivity, quality, and efficiency of both industry and Department of Energy enterprises, Los Alamos National Laboratory is investigating various manufacturing and business enterprise simulation methods. A number of enterprise simulation software models are being developed to enable engineering analysis of enterprise activities. In this document the authors define the scope of enterprise modeling and simulation efforts, and review recent work in enterprise simulation at Los Alamos National Laboratory as well as at other industrial, academic, and research institutions. References of enterprise modeling and simulation methods and a glossary of enterprise-related terms are provided.

  11. Advances in the modeling of single electron transistors for the design of integrated circuit.

    PubMed

    Chi, Yaqing; Sui, Bingcai; Yi, Xun; Fang, Liang; Zhou, Hailiang

    2010-09-01

    Single electron transistor (SET) has become a promising candidate for the key device of logic circuit in the near future. The advances of recent 5 years in the modeling of SETs are reviewed for the simulation of SET/hybrid CMOS-SET integrated circuit. Three dominating SET models, Monte Carlo model, master equation model and macro model, are analyzed, tested and compared on their principles, characteristics, applicability and development trend. The Monte Carlo model is suitable for SET structure research and simulation of small scale SET circuit, while the analytical model based on combination with master equation and macro model is suitable to simulate the SET circuit at balanceable efficiency and accuracy. PMID:21133161

  12. A Computational Methodology for Simulating Thermal Loss Testing of the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Reid, Terry V.; Wilson, Scott D.; Schifer, Nicholas A.; Briggs, Maxwell H.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot end and cold end temperatures, and specified electrical power output for a given net heat input. In an effort to improve net heat input predictions, numerous tasks have been performed which provided a more accurate value for net heat input into the ASCs, including the use of multidimensional numerical models. Validation test hardware has also been used to provide a direct comparison of numerical results and validate the multi-dimensional numerical models used to predict convertor net heat input and efficiency. These validation tests were designed to simulate the temperature profile of an operating Stirling convertor and resulted in a measured net heat input of 244.4 W. The methodology was applied to the multi-dimensional numerical model which resulted in a net heat input of 240.3 W. The computational methodology resulted in a value of net heat input that was 1.7 percent less than that measured during laboratory testing. The resulting computational methodology and results are discussed.

  13. TOPICAL REVIEW: Modelling and simulation in reactive polymer processing

    NASA Astrophysics Data System (ADS)

    Castro, José M.; Cabrera Ríos, Mauricio; Mount-Campbell, Clark A.

    2004-05-01

    Modelling and simulation in reactive polymer processing have been active research areas for the past decades in academic institutions as well as within the industry. Both areas have played a key role in advancing and optimizing reactive polymer processing operations. The objective of this paper is to review the two major classifications of models used to simulate polymer processes: physics based models and empirical models. Additionally, a section on multiple criteria optimization using data envelopment analysis has been included for completeness. The work presented here helps define a decision-making framework for the creation of reactive polymer process models and for the effective selection of settings of the process variables based on these models.

  14. Cavity Design and Beam Simulations for the APS RF Gun Advanced Photon Source

    E-print Network

    Kemner, Ken

    LS-186 Cavity Design and Beam Simulations for the APS RF Gun Advanced Photon Source Michael Borland for the APS RF gun. This note describes the final design, including cavity properties and simulation results expansion for the RF fields in the gun cavity, and stated that the amount of nonlinearity could be gauged

  15. Evaluation of advanced fuzzy logic PSS on analog network simulator and actual installation on hydro generators

    Microsoft Academic Search

    T. Hiyama; S. Oniki; H. Nagashima

    1996-01-01

    This paper presents the experimental evaluation of an advanced fuzzy logic PSS on the analog network simulator at the Research Laboratory of Kyushu Electric Power Co., Inc. The proposed power system stabilizer (PSS) is set up by using a personal computer with A\\/D and D\\/A conversion interfaces. The personal computer based PSS was set on the analog network simulator to

  16. High-Fidelity Simulation Training in Advanced Resuscitation for Pharmacy Residents

    PubMed Central

    Namba, Jennifer M.; Box, Kevin W.; Lane, James R.; Kim, Dennis Y.; Davis, Daniel P.; Doucet, Jay J.; Coimbra, Raul

    2014-01-01

    Objective. To assess the impact of high-fidelity patient simulation on pharmacy resident knowledge, confidence, and competency with advanced resuscitation algorithms and interventions. Design. An overview of the institutional cardiopulmonary arrest algorithm and a review of pertinent medications and calculations were presented to postgraduate year 1 (PGY1) pharmacy residents, followed by participation in 3 simulated clinical scenarios using a high-fidelity mannequin. Assessment. An improvement of pharmacy resident knowledge, confidence, and competency with advanced resuscitation skills was observed. In addition, pharmacy residents demonstrated high performance levels with skills requiring advanced competency and proactive interactions with the cardiac arrest team. Conclusion. Incorporating high-fidelity patient simulation into an advanced resuscitation training program can help pharmacy residents achieve competency through the active learning of practical skills. PMID:24761020

  17. NPSNET: Flight Simulation Dynamic Modeling Using Quaternions

    Microsoft Academic Search

    Joseph M. Cooke; Michael Zyda; David R. Pratt; Robert B. Mcghee

    1992-01-01

    The Naval Postgraduate School (NPS) has actively explored the design and implementation of networked, real time, three-dimensional battlefield simulations on low cost, commercially available graphics workstations. The most recent system, NPSNET, has improved in functionality to such an extent that it is considered a low cost version of the Defense Advanced Research Project Agency's (DARPA) SIMNET system. In order to

  18. Credibility Evaluation of Missile Flight Simulation Model

    Microsoft Academic Search

    Yanyan Zhou; Dongyang Zhang; Baoxiang Ren

    2010-01-01

    In this paper, credibility evaluation issue of missile flight simulation model is studying by applying neural network technique. Aiming at the subsistent insufficiency of model validation method in application, we present a credibility evaluation method based on neural network. Which uses the powerful ability of nonlinearity mapping of neural network by utilizing missile flight state data of simulation model as

  19. A Distributed Simulation Facility to Support Human Factors Research in Advanced Air Transportation Technology

    NASA Technical Reports Server (NTRS)

    Amonlirdviman, Keith; Farley, Todd C.; Hansman, R. John, Jr.; Ladik, John F.; Sherer, Dana Z.

    1998-01-01

    A distributed real-time simulation of the civil air traffic environment developed to support human factors research in advanced air transportation technology is presented. The distributed environment is based on a custom simulation architecture designed for simplicity and flexibility in human experiments. Standard Internet protocols are used to create the distributed environment, linking all advanced cockpit simulator, all Air Traffic Control simulator, and a pseudo-aircraft control and simulation management station. The pseudo-aircraft control station also functions as a scenario design tool for coordinating human factors experiments. This station incorporates a pseudo-pilot interface designed to reduce workload for human operators piloting multiple aircraft simultaneously in real time. The application of this distributed simulation facility to support a study of the effect of shared information (via air-ground datalink) on pilot/controller shared situation awareness and re-route negotiation is also presented.

  20. Aeroacoustic simulation for phonation modeling

    NASA Astrophysics Data System (ADS)

    Irwin, Jeffrey; Hanford, Amanda; Craven, Brent; Krane, Michael

    2011-11-01

    The phonation process occurs as air expelled from the lungs creates a pressure drop and a subsequent air flow across the larynx. The fluid-structure interaction between the turbulent air flow and oscillating vocal folds, combined with additional resonance in the oral and nasal cavities, creates much of what we hear in the human voice. As many voice-related disorders can be traced to irregular vocal tract shape or motion, it is important to understand in detail the physics involved in the phonation process. To numerically compute the physics of phonation, a solver must be able to accurately model acoustic airflow through a moving domain. The open-source CFD package OpenFOAM is currently being used to evaluate existing solvers against simple acoustic test cases, including an open-ended resonator and an expansion chamber, both of which utilize boundary conditions simulating acoustic sources as well as anechoic termination. Results of these test cases will be presented and compared with theory, and the future development of a three-dimensional vocal tract model and custom-mode acoustic solver will be discussed. Acknowledge support of NIH grant 5R01DC005642 and ARL E&F program.

  1. Theory, Modeling, and Simulation of Semiconductor Lasers

    NASA Technical Reports Server (NTRS)

    Ning, Cun-Zheng; Saini, Subbash (Technical Monitor)

    1998-01-01

    Semiconductor lasers play very important roles in many areas of information technology. In this talk, I will first give an overview of semiconductor laser theory. This will be followed by a description of different models and their shortcomings in modeling and simulation. Our recent efforts in constructing a fully space and time resolved simulation model will then be described. Simulation results based on our model will be presented. Finally the effort towards a self-consistent and comprehensive simulation capability for the opto-electronics integrated circuits (OEICs) will be briefly reviewed.

  2. Verification, validation and accreditation of simulation models

    Microsoft Academic Search

    Robert G. Sargent

    2000-01-01

    The paper discusses verification, validation, and accreditation of simulation models. The different approaches to deciding model validity are presented; how model verification and validation relate to the model development process are discussed; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are described; ways to document results are given; a recommended procedure is presented;

  3. Design tradeoffs in the development of the advanced multispectral simulation test acceptance resource (AMSTAR) HWIL facilities

    NASA Astrophysics Data System (ADS)

    LeSueur, Kenneth G.; Almendinger, Frank J.

    2007-04-01

    The Army's Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) is a suite of missile Hardware-In-the-Loop (HWIL) simulation / test capabilities designed to support testing from concept through production. This paper presents the design tradeoffs that were conducted in the development of the AMSTAR sensor stimulators and the flight motion simulators. The AMSTAR facility design includes systems to stimulate each of the Millimeter Wave (MMW), Infrared (IR), and Semi-Active Laser (SAL) sensors. The flight motion simulator (FMS) performance was key to the success of the simulation but required many concessions to accommodate the design considerations for the tri-mode stimulation systems.

  4. Advanced adaptive computational methods for Navier-Stokes simulations in rotorcraft aerodynamics

    NASA Technical Reports Server (NTRS)

    Stowers, S. T.; Bass, J. M.; Oden, J. T.

    1993-01-01

    A phase 2 research and development effort was conducted in area transonic, compressible, inviscid flows with an ultimate goal of numerically modeling complex flows inherent in advanced helicopter blade designs. The algorithms and methodologies therefore are classified as adaptive methods, which are error estimation techniques for approximating the local numerical error, and automatically refine or unrefine the mesh so as to deliver a given level of accuracy. The result is a scheme which attempts to produce the best possible results with the least number of grid points, degrees of freedom, and operations. These types of schemes automatically locate and resolve shocks, shear layers, and other flow details to an accuracy level specified by the user of the code. The phase 1 work involved a feasibility study of h-adaptive methods for steady viscous flows, with emphasis on accurate simulation of vortex initiation, migration, and interaction. Phase 2 effort focused on extending these algorithms and methodologies to a three-dimensional topology.

  5. Modelling and simulation of a heat exchanger

    NASA Technical Reports Server (NTRS)

    Xia, Lei; Deabreu-Garcia, J. Alex; Hartley, Tom T.

    1991-01-01

    Two models for two different control systems are developed for a parallel heat exchanger. First by spatially lumping a heat exchanger model, a good approximate model which has a high system order is produced. Model reduction techniques are applied to these to obtain low order models that are suitable for dynamic analysis and control design. The simulation method is discussed to ensure a valid simulation result.

  6. A simulation oriented animation description model

    Microsoft Academic Search

    Huadoug Ma; Shenquan Liu

    1994-01-01

    Introduces a simulation-oriented animation description model-the temporal logic-based animation description (TLAD) model-and an animation description language based on this model. This model has a powerful description ability, is easy to implement and convenient to use. The model can be used to describe complex animation simulations such as concurrency and path planning. Finally, we describe how to implement an animation system

  7. Modeling supersclar processors via statisical simulation

    Microsoft Academic Search

    Richard Carl; J. E. Smith

    1998-01-01

    Statistical simulation is a technique for fast per-formance evaluation of superscalar processors. First, intrinsic statistical information is collected from a single detailed simulation of a program. This information is then used to generate a synthetic instruction trace that is fed to a simple processor model, along with cache and branch prediction statistics. Because of the probabilistic nature of the simulation,

  8. Modeling and simulation of WSN routing protocols

    Microsoft Academic Search

    Xiaoyu Song

    2011-01-01

    In this paper, the simulation and analysis are given to the network simulation tool OPNET network model of the LEACH protocol. The simulation results show that the improved routing algorithm I-LEACH (Improved-LEACH) is better than the original LEACH algorithm that extends the network life cycle, reducing the overall system energy consumption and enhancing the network scalability.

  9. Monte Carlo Simulations of Model Nonionic Surfactants

    E-print Network

    Monte Carlo Simulations of Model Nonionic Surfactants A.P. Chatterjee and A.Z. Panagiotopoulos was studied by histogram reweight- ing grand canonical Monte Carlo simulations. Two di erent sets of site volume fractions using lattice Monte Carlo simulations performed in the canonical constant NV T ensemble

  10. Advances in a European Planetary Simulation Wind Tunnel Facility

    NASA Astrophysics Data System (ADS)

    Merrison, J.; Aye, K. M.; Holstein-Rathlou, C.; Mason, J.; Merlone, A.; Nørnberg, P.; Patel, M.; Portyankina, G.; Rasmussen, K. R.

    2012-09-01

    The Mars Simulation wind tunnel at Aarhus University is a unique ESA and EU supported simulation facility designed for studies of the Martian environment. Specifically it is capable of recreating the key physical parameters such as temperature, pressure (composition), wind flow and importantly the suspension of dust particulates. This facility is available to the scientific community for collaborative research. Preliminary results from the first year of facility operations will be presented.

  11. ADVANCE-Nebraska Logic Model ! Showcase Visitors

    E-print Network

    Farritor, Shane

    Diversity Grants ! Recruitment Ambassadors ! Search Committee Visits " ! Committees ! Chair Workshops # Institutionalized Increased knowledge of network connections in STEM departments KEY http://advance.unl.edu/ ! Lack of networking opportunities ! Number of UNL STEM women in leadership positions increased Conduct innovative

  12. Large Eddy Simulations and Turbulence Modeling for Film Cooling

    NASA Technical Reports Server (NTRS)

    Acharya, Sumanta

    1999-01-01

    The objective of the research is to perform Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) for film cooling process, and to evaluate and improve advanced forms of the two equation turbulence models for turbine blade surface flow analysis. The DNS/LES were used to resolve the large eddies within the flow field near the coolant jet location. The work involved code development and applications of the codes developed to the film cooling problems. Five different codes were developed and utilized to perform this research. This report presented a summary of the development of the codes and their applications to analyze the turbulence properties at locations near coolant injection holes.

  13. Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David; Reid, Robert; Adams, Mike; Davis, Joe

    2008-01-01

    Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

  14. A mathematical representation of an advanced helicopter for piloted simulator investigations of control system and display variations

    NASA Technical Reports Server (NTRS)

    Aiken, E. W.

    1980-01-01

    A mathematical model of an advanced helicopter is described. The model is suitable for use in control/display research involving piloted simulation. The general design approach for the six degree of freedom equations of motion is to use the full set of nonlinear gravitational and inertial terms of the equations and to express the aerodynamic forces and moments as the reference values and first order terms of a Taylor series expansion about a reference trajectory defined as a function of longitudinal airspeed. Provisions for several different specific and generic flight control systems are included in the model. The logic required to drive various flight control and weapon delivery symbols on a pilot's electronic display is also provided. Finally, the model includes a simplified representation of low altitude wind and turbulence effects. This model was used in a piloted simulator investigation of the effects of control system and display variations for an attack helicopter mission.

  15. Advanced microwave forward model for the land surface data assimilation

    NASA Astrophysics Data System (ADS)

    Park, Chang-Hwan; Pause, Marion; Gayler, Sebastian; Wollschlaeger, Ute; Jackson, Thomas J.; LeDrew, Ellsworth; Behrendt, Andreas; Wulfmeyer, Volker

    2015-04-01

    From local to global scales, microwave remote-sensing techniques can provide temporally and spatially highly resolved observations of land surface properties including soil moisture and temperature as well as the state of vegetation. These variables are critical for agricultural productivity and water resource management. Furthermore, having accurate information of these variables allows us to improve the performances of numerical weather forecasts and climate prediction models. However, it is challenging to translate a measured brightness temperature into the multiple land surface properties because of the inherent inversion problem. In this study, we introduce a novel forward model for microwave remote sensing to resolve this inversion problem and to close the gap between land surface modeling and observations. It is composed of the Noah-MP land surface model as well as new models for the dielectric mixing and the radiative transfer. For developing a realistic forward operator, the land surface model must simulate soil and vegetation processes properly. The Noah-MP land surface model provides an excellent starting point because it contains already a sophisticated soil texture and land cover data set. Soil moisture transport is derived using the Richards equation in combination with a set of soil hydraulic parameters. Vegetation properties are considered using several photosynthesis models with different complexity. The energy balance is closed for the top soil and the vegetation layers. The energy flux becomes more realistic due to including not only the volumetric ratio of land surface properties but also their surface fraction as sub-grid scale information (semitile approach). Dielectric constant is the fundamental link to quantify the land surface properties. Our physical based new dielectric-mixing model is superior to previous calibration and semi-empirical approaches. Furthermore, owing to the consideration of the oversaturated surface dielectric behaviour, a significant improvement by new approach would be expected in monitoring surface runoff and infiltration, managing and improving irrigation system, and mapping and predicting flood events. Finally, the novel dielectric-mixing model is able to successfully integrate the land surface model and the dielectric constant of microwave. Radiative transfer is calculated for the bare soil and the vegetated components of the grid box using a two-stream radiative transfer model. These model characteristics provide all relevant information needed for a simulation of the microwave emission from the land surface with unprecedented realism. Noah-MP is coupled with the Weather Research and Forecasting (WRF) model system. Also, the novel dielectric-mixing model physically links the Noah-MP land surface properties and the microwave effective dielectric constant. Finally, with the existing radiative transfer model the advanced forward model can assimilate microwave brightness temperature into a consistent land-surface-atmosphere system. A case study will be provided to investigate how well the simulation of the forward model matches to the real world. L-band microwave remote-sensing measurements over the Schäfertal region in Germany have been used for this case study.

  16. Advanced SAR simulator with multi-beam interferometric capabilities

    NASA Astrophysics Data System (ADS)

    Reppucci, Antonio; Márquez, José; Cazcarra, Victor; Ruffini, Giulio

    2014-10-01

    State of the art simulations are of great interest when designing a new instrument, studying the imaging mechanisms due to a given scenario or for inversion algorithm design as they allow to analyze and understand the effects of different instrument configurations and targets compositions. In the framework of the studies about a new instruments devoted to the estimation of the ocean surface movements using Synthetic Aperture Radar along-track interferometry (SAR-ATI) an End-to-End simulator has been developed. The simulator, built in a high modular way to allow easy integration of different processing-features, deals with all the basic operations involved in an end to end scenario. This includes the computation of the position and velocity of the platform (airborne/spaceborne) and the geometric parameters defining the SAR scene, the surface definition, the backscattering computation, the atmospheric attenuation, the instrument configuration, and the simulation of the transmission/reception chains and the raw data. In addition, the simulator provides a inSAR processing suit and a sea surface movement retrieval module. Up to four beams (each one composed by a monostatic and a bistatic channel) can be activated. Each channel provides raw data and SLC images with the possibility of choosing between Strip-map and Scansar modes. Moreover, the software offers the possibility of radiometric sensitivity analysis and error analysis due atmospheric disturbances, instrument-noise, interferogram phase-noise, platform velocity and attitude variations. In this paper, the architecture and the capabilities of this simulator will be presented. Meaningful simulation examples will be shown.

  17. Model Validation with Hybrid Dynamic Simulation

    SciTech Connect

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

    2006-06-22

    Abstract—Model 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.

  18. Advances in the U.S. Navy Non-hydrostatic Unified Model of the Atmosphere (NUMA): LES as a Stabilization Methodology for High-Order Spectral Elements in the Simulation of Deep Convection

    NASA Astrophysics Data System (ADS)

    Marras, Simone; Giraldo, Frank

    2015-04-01

    The prediction of extreme weather sufficiently ahead of its occurrence impacts society as a whole and coastal communities specifically (e.g. Hurricane Sandy that impacted the eastern seaboard of the U.S. in the fall of 2012). With the final goal of solving hurricanes at very high resolution and numerical accuracy, we have been developing the Non-hydrostatic Unified Model of the Atmosphere (NUMA) to solve the Euler and Navier-Stokes equations by arbitrary high-order element-based Galerkin methods on massively parallel computers. NUMA is a unified model with respect to the following criteria: (a) it is based on unified numerics in that element-based Galerkin methods allow the user to choose between continuous (spectral elements, CG) or discontinuous Galerkin (DG) methods and from a large spectrum of time integrators, (b) it is unified across scales in that it can solve flow in limited-area mode (flow in a box) or in global mode (flow on the sphere). NUMA is the dynamical core that powers the U.S. Naval Research Laboratory's next-generation global weather prediction system NEPTUNE (Navy's Environmental Prediction sysTem Utilizing the NUMA corE). Because the solution of the Euler equations by high order methods is prone to instabilities that must be damped in some way, we approach the problem of stabilization via an adaptive Large Eddy Simulation (LES) scheme meant to treat such instabilities by modeling the sub-grid scale features of the flow. The novelty of our effort lies in the extension to high order spectral elements for low Mach number stratified flows of a method that was originally designed for low order, adaptive finite elements in the high Mach number regime [1]. The Euler equations are regularized by means of a dynamically adaptive stress tensor that is proportional to the residual of the unperturbed equations. Its effect is close to none where the solution is sufficiently smooth, whereas it increases elsewhere, with a direct contribution to the stabilization of the otherwise oscillatory solution. As a first step toward the Large Eddy Simulation of a hurricane, we verify the model via a high-order and high resolution idealized simulation of deep convection on the sphere. References [1] M. Nazarov and J. Hoffman (2013) Residual-based artificial viscosity for simulation of turbulent compressible flow using adaptive finite element methods Int. J. Numer. Methods Fluids, 71:339-357

  19. Multiphase flow in the advanced fluid dynamics model

    SciTech Connect

    Bohl, W.R.; Wilhelm, D.; Berthier, J.; Parker, F.P.; Ichikawa, S.; Goutagny, L.; Ninokata, H.

    1988-01-01

    This paper describes the modeling used in the Advanced Fluid Dynamics Model (AFDM), a computer code to investigate new approaches to simulating severe accidents in fast reactors. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, the dominant liquid, and the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow are permitted for the pool situations modeled. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas also are modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer generally is treated using engineering correlations. Liquid/vapor phase transitions are handled with a nonequililbrium heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. The Los Alamos SESAME equation of state (EOS) has been inplemented using densities and temperatures as the independent variables. A summary description of the AFDM numerical algorithm is provided. The AFDM code currently is being debugged and checked out. Two sample three-field calculations also are presented. The first is a three-phase bubble column mixing experiment performed at Argonne National Laboratory; the second is a liquid-liquid mixing experiment performed at Kernforschungszentrum, Karlsruhe, that resulted in rapid vapor production. We conclude that only qualitative comparisons currently are possible for complex multiphase situations. Many further model developments can be pursued, but there are limits because of the lack of a comprehensive theory, the lack of detailed multicomponent experimental data, and the difficulties in keeping the resulting model complexities tractable.

  20. Simulation model of a twin-tail, high performance airplane

    NASA Technical Reports Server (NTRS)

    Buttrill, Carey S.; Arbuckle, P. Douglas; Hoffler, Keith D.

    1992-01-01

    The mathematical model and associated computer program to simulate a twin-tailed high performance fighter airplane (McDonnell Douglas F/A-18) are described. The simulation program is written in the Advanced Continuous Simulation Language. The simulation math model includes the nonlinear six degree-of-freedom rigid-body equations, an engine model, sensors, and first order actuators with rate and position limiting. A simplified form of the F/A-18 digital control laws (version 8.3.3) are implemented. The simulated control law includes only inner loop augmentation in the up and away flight mode. The aerodynamic forces and moments are calculated from a wind-tunnel-derived database using table look-ups with linear interpolation. The aerodynamic database has an angle-of-attack range of -10 to +90 and a sideslip range of -20 to +20 degrees. The effects of elastic deformation are incorporated in a quasi-static-elastic manner. Elastic degrees of freedom are not actively simulated. In the engine model, the throttle-commanded steady-state thrust level and the dynamic response characteristics of the engine are based on airflow rate as determined from a table look-up. Afterburner dynamics are switched in at a threshold based on the engine airflow and commanded thrust.

  1. Modeling and Simulation of Water Allocation System Based on Simulated Annealing Hybrid Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Zhu, Jiulong; Wang, Shijun

    Presently water resource in most watersheds in China is distributed in terms of administrative instructions. This kind of allocation method has many disadvantages and hampers the instructional effect of market mechanism on water allocation. The paper studies South-to-North Water Transfer Project and discusses water allocation of the node lakes along the Project. Firstly, it advanced four assumptions. Secondly, it analyzed constraint conditions of water allocation in terms of present state of water allocation in China. Thirdly, it established a goal model of water allocation and set up a systematic model from the angle of comprehensive profits of water utilization and profits of the node lakes. Fourthly, it discussed calculation method of the model by means of Simulated Annealing Hybrid Genetic Algorithm (SHGA). Finally, it validated the rationality and validity of the model by a simulation testing.

  2. Analysis and Modeling of Parasitic Capacitances in Advanced Nanoscale Devices

    E-print Network

    Bekal, Prasanna

    2012-07-16

    In order to correctly perform circuit simulation, it is crucial that parasitic capacitances near devices are accurately extracted and are consistent with the SPICE models. Although 3D device simulation can be used to extract such parasitics...

  3. SSA Modeling and Simulation with DIRSIG

    NASA Astrophysics Data System (ADS)

    Bennett, D.; Allen, D.; Dank, J.; Gartley, M.; Tyler, D.

    2014-09-01

    We describe and demonstrate a robust, physics-based modeling system to simulate ground and space-based observations of both LEO and GEO objects. With the DIRSIG radiometry engine at its core, our system exploits STK, adaptive optics modeling, and detector effects to produce high fidelity simulated images and radiometry. Key to generating quantitative simulations is our ability to attribute engineering-quality, faceted CAD models with reflective and emissive properties derived from laboratory measurements, including the spatial structure of such difficult materials as MLI. In addition to simulated video imagery, we will demonstrate a computational procedure implementing a position-based dynamics approach to shrink wrap MLI around space components.

  4. VHDL simulation with access to transistor models

    NASA Technical Reports Server (NTRS)

    Gibson, J.

    1991-01-01

    Hardware description languages such as VHDL have evolved to aid in the design of systems with large numbers of elements and a wide range of electronic and logical abstractions. For high performance circuits, behavioral models may not be able to efficiently include enough detail to give designers confidence in a simulation's accuracy. One option is to provide a link between the VHDL environment and a transistor level simulation environment. The coupling of the Vantage Analysis Systems VHDL simulator and the NOVA simulator provides the combination of VHDL modeling and transistor modeling.

  5. Advances in Discrete-Event Simulation for MSL Command Validation

    NASA Technical Reports Server (NTRS)

    Patrikalakis, Alexander; O'Reilly, Taifun

    2013-01-01

    In the last five years, the discrete event simulator, SEQuence GENerator (SEQGEN), developed at the Jet Propulsion Laboratory to plan deep-space missions, has greatly increased uplink operations capacity to deal with increasingly complicated missions. In this paper, we describe how the Mars Science Laboratory (MSL) project makes full use of an interpreted environment to simulate change in more than fifty thousand flight software parameters and conditional command sequences to predict the result of executing a conditional branch in a command sequence, and enable the ability to warn users whenever one or more simulated spacecraft states change in an unexpected manner. Using these new SEQGEN features, operators plan more activities in one sol than ever before.

  6. Dasor, a grid model based simulation library

    Microsoft Academic Search

    Alain Bui; Olivier Flauzac

    Simulation is a key point for designing applications for large scale networks like grids or peer-to-peer networks. To be relevant, simula- tions must be computed with adequate models: communication models, fault models or network models (bandwidth, latency). In previous works, we proposed a ve layer model to map grid applications and the subja- cent network. Particularly, it shows how subjacent

  7. Advanced Gas Laser Experiments and Modeling D. L. Carroll1

    E-print Network

    Carroll, David L.

    pumped alkali laser (DPAL), the exciplex pumped alkali laser (XPAL), and the optically pumped metastableAdvanced Gas Laser Experiments and Modeling D. L. Carroll1 , J. W. Zimmerman2 , B. S. Woodard2 , G University of Illinois at Urbana-Champaign, Urbana, IL 61801 Over the last decade new advanced gas lasers

  8. Modelling and simulation of large neural networks

    Microsoft Academic Search

    F. J. Lopez-Aligue; C. Garcia-Orellana; I. Acevedo-Sotoca; H. Gonzalez-Velasco; M. Macias-Macias

    1999-01-01

    We propose an object oriented model for the simulation of large neural networks using the OMTechnique. This modelling has been implemented on a client-server simulator (called NeSim-NNLIB), the server being a “beowulf” cluster, getting up to 18 MCPS with a cluster of 6 Pentium processors

  9. Crop Simulation Models and Decision Support Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first computer simulation models for agricultural systems were developed in the 1970s. These early models simulated potential production for major crops as a function of weather conditions, especially temperature and solar radiation. At a later stage, the water component was added to be able to ...

  10. Submarine landslide flows simulation through centrifuge modelling

    E-print Network

    Gue, Chang Shin

    2012-05-08

    SUBMARINE LANDSLIDE FLOWS SIMULATION THROUGH CENTRIFUGE MODELLING by Chang Shin GUE A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge Churchill College January... “Continuous effort – not strength or intelligence – is the key to unlocking our potential” - Winston Churchill ABSTRACT SUBMARINE LANDSLIDE FLOWS SIMULATION THROUGH CENTRIFUGE MODELLING Chang Shin GUE Landslides occur both onshore...

  11. Monte Carlo Simulation of Interacting Electron Models

    E-print Network

    Robinson, Robert W.

    Monte Carlo Simulation of Interacting Electron Models by a New Determinant Approach by Mucheng discusses the calculation of determinants and Monte Carlo simulation of Hub- bard models by a new and a Monte Carlo summation algorithm to evaluate the relevant diagram determinant sums. Index words: Monte

  12. Developments in Atmosphere Revitalization Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Knox, James C.; Kittredge, Kenneth; Xoker, Robert F.; Cummings, Ramona; Gomez, Carlos F.

    2012-01-01

    "NASA's Advanced Exploration Systems (AES) program is pioneering new approaches for rapidly developing prototype systems, demonstrating key capabilities, and validating operational concepts for future human missions beyond Earth orbit" (NASA 2012). These forays beyond the confines of earth's gravity will place unprecedented demands on launch systems. They must not only blast out of earth's gravity well as during the Apollo moon missions, but also launch the supplies needed to sustain a crew over longer periods for exploration missions beyond earth's moon. Thus all spacecraft systems, including those for the separation of metabolic carbon dioxide and water from a crewed vehicle, must be minimized with respect to mass, power, and volume. Emphasis is also placed on system robustness both to minimize replacement parts and ensure crew safety when a quick return to earth is not possible. Current efforts are focused on improving the current state-of-the-art systems utilizing fixed beds of sorbent pellets by evaluating structured sorbents, seeking more robust pelletized sorbents, and examining alternate bed configurations to improve system efficiency and reliability. These development efforts combine testing of sub-scale systems and multi-physics computer simulations to evaluate candidate approaches, select the best performing options, and optimize the configuration of the selected approach, which is then implemented in a full-scale integrated atmosphere revitalization test. This paper describes the development of atmosphere revitalization models and simulations. A companion paper discusses the hardware design and sorbent screening and characterization effort in support of the Atmosphere Revitalization Recovery and Environmental Monitoring (ARREM) project within the AES program.

  13. Structural equations modeling: Fit Indices, sample size, and advanced topics

    Microsoft Academic Search

    Dawn Iacobucci

    2010-01-01

    This article is the second of two parts intended to serve as a primer for structural equations models for the behavioral researcher. The first article introduced the basics: the measurement model, the structural model, and the combined, full structural equations model. In this second article, advanced issues are addressed, including fit indices and sample size, moderators, longitudinal data, mediation, and

  14. AFDM: An Advanced Fluid-Dynamics Model. Volume 1: Scope, approach, and summary

    Microsoft Academic Search

    W. R. Bohl; F. R. Parker; D. Wilhelm; J. Berthier; L. Goutagny; H. Ninokata

    1990-01-01

    AFDM, or the Advanced Fluid-Dynamics Model, is a computer code that investigates new approaches simulating the multiphase-flow fluid-dynamics aspects of severe accidents in fast reactors. The AFDM formalism starts with differential equations similar to those in the SIMMER-II code. These equations are modified to treat three velocity fields and supplemented with a variety of new models. The AFDM code has

  15. The Advancement Value Chain: An Exploratory Model

    ERIC Educational Resources Information Center

    Leonard, Edward F., III

    2005-01-01

    Since the introduction of the value chain concept in 1985, several varying, yet virtually similar, value chains have been developed for the business enterprise. Shifting to higher education, can a value chain be found that links together the various activities of advancement so that an institution's leaders can actually look at the philanthropic…

  16. Simulating data processing for an Advanced Ion Mobility Mass Spectrometer

    SciTech Connect

    Chavarría-Miranda, Daniel; Clowers, Brian H.; Anderson, Gordon A.; Belov, Mikhail E.

    2007-11-03

    We have designed and implemented a Cray XD-1-based sim- ulation of data capture and signal processing for an ad- vanced Ion Mobility mass spectrometer (Hadamard trans- form Ion Mobility). Our simulation is a hybrid application that uses both an FPGA component and a CPU-based soft- ware component to simulate Ion Mobility mass spectrome- try data processing. The FPGA component includes data capture and accumulation, as well as a more sophisticated deconvolution algorithm based on a PNNL-developed en- hancement to standard Hadamard transform Ion Mobility spectrometry. The software portion is in charge of stream- ing data to the FPGA and collecting results. We expect the computational and memory addressing logic of the FPGA component to be portable to an instrument-attached FPGA board that can be interfaced with a Hadamard transform Ion Mobility mass spectrometer.

  17. Using advanced industrial robotics for spacecraft Rendezvous and Docking simulation

    Microsoft Academic Search

    Toralf Boge; Ou Ma

    2011-01-01

    One of the most challenging and risky missions for spacecraft is to perform Rendezvous and Docking (RvD) autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes a new, robotics-based, hardware-in-the-loop RvD simulation facility which uses two industrial robots

  18. Advanced wellbore thermal simulator: GEOTEMP2 user manual

    SciTech Connect

    Mitchell, R.F.

    1982-02-01

    GEOTEMP2 is a wellbore thermal simulator designed for geothermal well drilling and production problems. GEOTEMP2 includes the following features: fully transient heat conduction, wellbore fluid flow options, well completion options, and drilling-production histories. The data input format is given, along with input examples and comments on special features of the input. Ten examples that illustrate all of the flowing options and input options in GEOTEMP2 are included.

  19. DETECTION, PROPAGATION MODELING AND DESIGNING OF ADVANCED INTERNET WORMS

    E-print Network

    Fang, Yuguang "Michael"

    DETECTION, PROPAGATION MODELING AND DESIGNING OF ADVANCED INTERNET WORMS By PARBATI KUMAR MANNA.1 The Computer Worm: A Brief History . . . . . . . . . . . . . . . . . . . . 14 1.2 Propagation Methods of a Worm-Level Behavior . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.3 Recent Trends Among Worms

  20. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    NASA Technical Reports Server (NTRS)

    Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

    2014-01-01

    This presentation describes the capabilities of three-dimensional thermal power model of advanced stirling radioisotope generator (ASRG). The performance of the ASRG is presented for different scenario, such as Venus flyby with or without the auxiliary cooling system.

  1. Radiation Damage in Nuclear Fuel for Advanced Burner Reactors: Modeling and Experimental Validation

    SciTech Connect

    Jensen, Niels Gronbech; Asta, Mark; Ozolins, Nigel Browning'Vidvuds; de Walle, Axel van; Wolverton, Christopher

    2011-12-29

    The consortium has completed its existence and we are here highlighting work and accomplishments. As outlined in the proposal, the objective of the work was to advance the theoretical understanding of advanced nuclear fuel materials (oxides) toward a comprehensive modeling strategy that incorporates the different relevant scales involved in radiation damage in oxide fuels. Approaching this we set out to investigate and develop a set of directions: 1) Fission fragment and ion trajectory studies through advanced molecular dynamics methods that allow for statistical multi-scale simulations. This work also includes an investigation of appropriate interatomic force fields useful for the energetic multi-scale phenomena of high energy collisions; 2) Studies of defect and gas bubble formation through electronic structure and Monte Carlo simulations; and 3) an experimental component for the characterization of materials such that comparisons can be obtained between theory and experiment.

  2. Modeling and simulation of blood collection systems.

    PubMed

    Alfonso, Edgar; Xie, Xiaolan; Augusto, Vincent; Garraud, Olivier

    2012-03-01

    This paper addresses the modeling and simulation of blood collection systems in France for both fixed site and mobile blood collection with walk in whole blood donors and scheduled plasma and platelet donors. Petri net models are first proposed to precisely describe different blood collection processes, donor behaviors, their material/human resource requirements and relevant regulations. Petri net models are then enriched with quantitative modeling of donor arrivals, donor behaviors, activity times and resource capacity. Relevant performance indicators are defined. The resulting simulation models can be straightforwardly implemented with any simulation language. Numerical experiments are performed to show how the simulation models can be used to select, for different walk in donor arrival patterns, appropriate human resource planning and donor appointment strategies. PMID:22048940

  3. Advanced EMI Modeling and Processing Approaches for UXO Discrimination

    Microsoft Academic Search

    F. Shubitidze; B. Barrowes; K. O'Neill; I. Shamatava

    2006-01-01

    This paper presents a new, advanced non-traditional physics based inverse-scattering approach for determining a buried object's location and orientation. The approach combines an advanced electromagnetic induction (EMI) forward model called the normalized surface magnetic charge model (NSMC) with the pole series expansions technique. First, the NSMC is used to generate bi-static EMI data from actual measured mono-static data, and then

  4. Advancing Software Architecture Modeling for Large Scale Heterogeneous Systems

    SciTech Connect

    Gorton, Ian; Liu, Yan

    2010-11-07

    In this paper we describe how incorporating technology-specific modeling at the architecture level can help reduce risks and produce better designs for large, heterogeneous software applications. We draw an analogy with established modeling approaches in scientific domains, using groundwater modeling as an example, to help illustrate gaps in current software architecture modeling approaches. We then describe the advances in modeling, analysis and tooling that are required to bring sophisticated modeling and development methods within reach of software architects.

  5. High-Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    DOE PAGESBeta

    Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

    2014-11-01

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing (HPC) are essential for accurately modeling them. In the past decade, the DOE SciDAC program has produced such accelerator-modeling tools, which have beem employed to tackle some of the most difficult accelerator science problems. In this article we discuss the Synergia beam-dynamics framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation packagemore »capable of handling the entire spectrum of beam dynamics simulations. We present the design principles, key physical and numerical models in Synergia and its performance on HPC platforms. Finally, we present the results of Synergia applications for the Fermilab proton source upgrade, known as the Proton Improvement Plan (PIP).« less

  6. High-Performance Computing Modeling Advances Accelerator Science for High-Energy Physics

    DOE PAGESBeta

    Amundson, James [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Macridin, Alexandru [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Spentzouris, Panagiotis [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2014-11-01

    The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing (HPC) are essential for accurately modeling them. In the past decade, the DOE SciDAC program has produced such accelerator-modeling tools, which have beem employed to tackle some of the most difficult accelerator science problems. In this article we discuss the Synergia beam-dynamics framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. We present the design principles, key physical and numerical models in Synergia and its performance on HPC platforms. Finally, we present the results of Synergia applications for the Fermilab proton source upgrade, known as the Proton Improvement Plan (PIP).

  7. Advanced distributed simulation technology: Digital Voice Gateway Reference Guide

    NASA Astrophysics Data System (ADS)

    Vanhook, Dan; Stadler, Ed

    1994-01-01

    The Digital Voice Gateway (referred to as the 'DVG' in this document) transmits and receives four full duplex encoded speech channels over the Ethernet. The information in this document applies only to DVG's running firmware of the version listed on the title page. This document, previously named Digital Voice Gateway Reference Guide, BBN Systems and Technologies Corporation, Cambridge, MA 02138, was revised for revision 2.00. This new revision changes the network protocol used by the DVG, to comply with the SINCGARS radio simulation (For SIMNET 6.6.1). Because of the extensive changes to revision 2.00 a separate document was created rather than supplying change pages.

  8. Microwave Processing of Simulated Advanced Nuclear Fuel Pellets

    SciTech Connect

    D.E. Clark; D.C. Folz

    2010-08-29

    Throughout the three-year project funded by the Department of Energy (DOE) and lead by Virginia Tech (VT), project tasks were modified by consensus to fit the changing needs of the DOE with respect to developing new inert matrix fuel processing techniques. The focus throughout the project was on the use of microwave energy to sinter fully stabilized zirconia pellets using microwave energy and to evaluate the effectiveness of techniques that were developed. Additionally, the research team was to propose fundamental concepts as to processing radioactive fuels based on the effectiveness of the microwave process in sintering the simulated matrix material.

  9. Virtual Environments for Advanced Modeling: Conceptual Foundations for Research

    Microsoft Academic Search

    Tung X. Bui; Hans-Juergen Sebastian; Daniel R. Dolk; Alexandre Gachet

    2005-01-01

    In this concept paper, we advocate for a paradigm shift in computational modeling. Advanced modeling should conceive new computational languages and models to describe real-life phenomena and solve real-life problems. Moreover, it should also be used to create \\

  10. Advanced terahertz imaging system performance model for concealed weapon identification

    NASA Astrophysics Data System (ADS)

    Murrill, Steven R.; Redman, Brian; Espinola, Richard L.; Franck, Charmaine C.; Petkie, Douglas T.; De Lucia, Frank C.; Jacobs, Eddie L.; Griffin, Steven T.; Halford, Carl E.; Reynolds, Joe

    2007-04-01

    The U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) and the U.S. Army Research Laboratory (ARL) have developed a terahertz-band imaging system performance model for detection and identification of concealed weaponry. The details of this MATLAB-based model which accounts for the effects of all critical sensor and display components, and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination, were reported on at the 2005 SPIE Europe Security and Defence Symposium. The focus of this paper is to report on recent advances to the base model which have been designed to more realistically account for the dramatic impact that target and background orientation can have on target observability as related to specular and Lambertian reflections captured by an active-illumination-based imaging system. The advanced terahertz-band imaging system performance model now also accounts for target and background thermal emission, and has been recast into a user-friendly, Windows-executable tool. This advanced THz model has been developed in support of the Defense Advanced Research Project Agency's (DARPA) Terahertz Imaging Focal-Plane Technology (TIFT) program. This paper will describe the advanced THz model and its new radiometric sub-model in detail, and provide modeling and experimental results on target observability as a function of target and background orientation.

  11. Software-Engineering Process Simulation (SEPS) model

    NASA Technical Reports Server (NTRS)

    Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

    1992-01-01

    The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

  12. The role of experience and advanced training on performance in a motorcycle simulator.

    PubMed

    Crundall, David; Stedmon, Alex W; Crundall, Elizabeth; Saikayasit, Rossukorn

    2014-12-01

    Motorcyclists are over-represented in collision statistics. While many collisions may be the direct fault of another road user, a considerable number of fatalities and injuries are due to the actions of the rider. While increased riding experience may improve skills, advanced training courses may be required to evoke the safest riding behaviours. The current research assessed the impact of experience and advanced training on rider behaviour using a motorcycle simulator. Novice riders, experienced riders and riders with advanced training traversed a virtual world through varying speed limits and roadways of different curvature. Speed and lane position were monitored. In a comparison of 60 mph and 40 mph zones, advanced riders rode more slowly in the 40 mph zones, and had greater variation in lane position than the other two groups. In the 60 mph zones, both advanced and experienced riders had greater lane variation than novices. Across the whole ride, novices tended to position themselves closer to the kerb. In a second analysis across four classifications of curvature (straight, slight, medium, tight) advanced and experienced riders varied their lateral position more so than novices, though advanced riders had greater variation in lane position than even experienced riders in some conditions. The results suggest that experience and advanced training lead to changes in behaviour compared to novice riders which can be interpreted as having a potentially positive impact on road safety. PMID:25180786

  13. Recent Improvements to an Advanced Atmospheric Transport Modeling System

    SciTech Connect

    Buckley, R. L.; Hunter, C. H.

    2005-10-24

    The Atmospheric Technologies Group (ATG) has developed an advanced atmospheric modeling capability using the Regional Atmospheric Modeling System (RAMS) and a stochastic Lagrangian particle dispersion model (LPDM) for operational use at the Savannah River Site (SRS). For local simulations concerning releases from the Central Savannah River Area (CSRA), RAMS is run in a nested grid configuration with horizontal grid spacing of 8 and 2 km for each grid, with 6-hr forecasts updated every 3 hours. An interface to allow for easy user access to LPDM had been generated, complete with post-processing results depicting surface concentration, deposition, and a variety of dose quantities. A prior weakness in this approach was that observations from the SRS tower network were only incorporated into the three-dimensional modeling effort during the initialization process. Thus, if the forecasted wind fields were in error, the resulting plume predictions would also be erroneous. To overcome this shortcoming, the procedure for generating RAMS wind fields and reading them into LPDM has been modified such that SRS wind measurements are blended with the predicted three-dimensional wind fields from RAMS using the Barnes technique. In particular, the horizontal components in RAMS are replaced with the observed values at a series of 8 towers that exist within the SRS boundary (covering {approx}300 km{sup 2}). Even though LPDM is currently configured to account only for radioactive releases, it was used in a recent chlorine gas release to generate plume concentrations based on unit releases from the site of a train accident in Graniteville, South Carolina. This information was useful to local responders as an indication of potential protective actions downwind of the release.

  14. Advanced Simulation Capability for Environmental Management - Current Status and Phase II Demonstration Results - 13161

    SciTech Connect

    Seitz, Roger R.; Flach, Greg [Savannah River National Laboratory, Savannah River Site, Bldg 773-43A, Aiken, SC 29808 (United States)] [Savannah River National Laboratory, Savannah River Site, Bldg 773-43A, Aiken, SC 29808 (United States); Freshley, Mark D.; Freedman, Vicky; Gorton, Ian [Pacific Northwest National Laboratory, MSIN K9-33, P.O. Box 999, Richland, WA 99352 (United States)] [Pacific Northwest National Laboratory, MSIN K9-33, P.O. Box 999, Richland, WA 99352 (United States); Dixon, Paul; Moulton, J. David [Los Alamos National Laboratory, MS B284, P.O. Box 1663, Los Alamos, NM 87544 (United States)] [Los Alamos National Laboratory, MS B284, P.O. Box 1663, Los Alamos, NM 87544 (United States); Hubbard, Susan S.; Faybishenko, Boris; Steefel, Carl I.; Finsterle, Stefan [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50B-4230, Berkeley, CA 94720 (United States)] [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50B-4230, Berkeley, CA 94720 (United States); Marble, Justin [Department of Energy, 19901 Germantown Road, Germantown, MD 20874-1290 (United States)] [Department of Energy, 19901 Germantown Road, Germantown, MD 20874-1290 (United States)

    2013-07-01

    The U.S. Department of Energy (US DOE) Office of Environmental Management (EM), Office of Soil and Groundwater, is supporting development of the Advanced Simulation Capability for Environmental Management (ASCEM). ASCEM is a state-of-the-art scientific tool and approach for understanding and predicting contaminant fate and transport in natural and engineered systems. The modular and open source high-performance computing tool facilitates integrated approaches to modeling and site characterization that enable robust and standardized assessments of performance and risk for EM cleanup and closure activities. The ASCEM project continues to make significant progress in development of computer software capabilities with an emphasis on integration of capabilities in FY12. Capability development is occurring for both the Platform and Integrated Tool-sets and High-Performance Computing (HPC) Multi-process Simulator. The Platform capabilities provide the user interface and tools for end-to-end model development, starting with definition of the conceptual model, management of data for model input, model calibration and uncertainty analysis, and processing of model output, including visualization. The HPC capabilities target increased functionality of process model representations, tool-sets for interaction with Platform, and verification and model confidence testing. The Platform and HPC capabilities are being tested and evaluated for EM applications in a set of demonstrations as part of Site Applications Thrust Area activities. The Phase I demonstration focusing on individual capabilities of the initial tool-sets was completed in 2010. The Phase II demonstration completed in 2012 focused on showcasing integrated ASCEM capabilities. For Phase II, the Hanford Site deep vadose zone (BC Cribs) served as an application site for an end-to-end demonstration of capabilities, with emphasis on integration and linkages between the Platform and HPC components. Other demonstrations, addressing attenuation-based remedies at the Savannah River Site F Area and performance assessment for a representative waste tank, illustrate integration of linked ASCEM capabilities and initial integration efforts with tools from the Cementitious Barriers Partnership. (authors)

  15. Advances in petascale kinetic plasma simulation with VPIC and Roadrunner

    SciTech Connect

    Bowers, Kevin J [Los Alamos National Laboratory; Albright, Brian J [Los Alamos National Laboratory; Yin, Lin [Los Alamos National Laboratory; Daughton, William S [Los Alamos National Laboratory; Roytershteyn, Vadim [Los Alamos National Laboratory; Kwan, Thomas J T [Los Alamos National Laboratory

    2009-01-01

    VPIC, a first-principles 3d electromagnetic charge-conserving relativistic kinetic particle-in-cell (PIC) code, was recently adapted to run on Los Alamos's Roadrunner, the first supercomputer to break a petaflop (10{sup 15} floating point operations per second) in the TOP500 supercomputer performance rankings. They give a brief overview of the modeling capabilities and optimization techniques used in VPIC and the computational characteristics of petascale supercomputers like Roadrunner. They then discuss three applications enabled by VPIC's unprecedented performance on Roadrunner: modeling laser plasma interaction in upcoming inertial confinement fusion experiments at the National Ignition Facility (NIF), modeling short pulse laser GeV ion acceleration and modeling reconnection in magnetic confinement fusion experiments.

  16. Tutorial on agent-based modeling and simulation.

    SciTech Connect

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2005-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS is a third way of doing science besides deductive and inductive reasoning. Computational advances have made possible a growing number of agent-based applications in a variety of fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling consumer behavior to understanding the fall of ancient civilizations, to name a few. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing ABMS models, and provides some thoughts on the relationship between ABMS and traditional modeling techniques.

  17. Investigation of advanced fault insertion and simulator methods

    NASA Technical Reports Server (NTRS)

    Dunn, W. R.; Cottrell, D.

    1986-01-01

    The cooperative agreement partly supported research leading to the open-literature publication cited. Additional efforts under the agreement included research into fault modeling of semiconductor devices. Results of this research are presented in this report which is summarized in the following paragraphs. As a result of the cited research, it appears that semiconductor failure mechanism data is abundant but of little use in developing pin-level device models. Failure mode data on the other hand does exist but is too sparse to be of any statistical use in developing fault models. What is significant in the failure mode data is that, unlike classical logic, MSI and LSI devices do exhibit more than 'stuck-at' and open/short failure modes. Specifically they are dominated by parametric failures and functional anomalies that can include intermittent faults and multiple-pin failures. The report discusses methods of developing composite pin-level models based on extrapolation of semiconductor device failure mechanisms, failure modes, results of temperature stress testing and functional modeling. Limitations of this model particularly with regard to determination of fault detection coverage and latency time measurement are discussed. Indicated research directions are presented.

  18. Numerical simulations of Hurricane Bertha using a mesoscale atmospheric model

    SciTech Connect

    Buckley, R.L.

    1996-08-01

    The Regional Atmospheric Model System (RAMS) has been used to simulate Hurricane Bertha as it moved toward and onto shore during the period July 10--12, 1996. Using large-scale atmospheric data from 00 UTC, 11 July (Wednesday evening) to initialize the model, a 36-hour simulation was created for a domain centered over the Atlantic Ocean east of the Florida coast near Jacksonville. The simulated onshore impact time of the hurricane was much earlier than observed (due to the use of results from the large-scale model, which predicted early arrival). However, the movement of the hurricane center (eye) as it approached the North Carolina/South Carolina coast as simulated in RAMS was quite good. Observations revealed a northerly storm track off the South Carolina coast as it moved toward land. As it approached landfall, Hurricane Bertha turned to the north-northeast, roughly paralleling the North Carolina coast before moving inland near Wilmington. Large-scale model forecasts were unable to detect this change in advance and predicted landfall near Myrtle Beach, South Carolina; RAMS, however, correctly predicted the parallel coastal movement. For future hurricane activity in the southeast, RAMS is being configured to run in an operational model using input from the large-scale pressure data in hopes of providing more information on predicted hurricane movement and landfall location.

  19. Advances on Time-dependent DFT Simulations of Electronic Stopping

    NASA Astrophysics Data System (ADS)

    Correa, Alfredo; Schleife, Andre; Kanai, Yosuke; Kohanoff, Jorge; Caro, Alfredo J.

    2012-02-01

    Radiation damage of reactor materials is a topic of interest and continuous research in the nuclear industry. A single nuclear decay event (e.g. alpha ) produces a cascade of collisions involving the displacement of thousands of atoms in a crystalline material. While atomistic-scale simulations would be the ideal tool to understand these processes, the fact that they currently work on the assumption that electrons respond adiabatically to the atomic motion does not provide valid answers, for example to the stopping power problem. An alternative approach to attacking this problem is a method which explicitly takes into account electron non-adiabatic dynamics. We will present results obtained by time-depending DFT on the electronic stopping power of channeling protons in prototypical metals and insulators obtained by recent implementations of non-adiabatic electron dynamics methods.

  20. The Advanced Photon Source linac modulators PSpice simulation and upgrade.

    SciTech Connect

    Cours, A.; Smith, T.

    2002-06-28

    The APS linac modulators provide DC pulses to Thales 35/45-MW klystrons. The modulators are pulse forming network (PFN)-type pulsers with EMI 40-kV switch-mode charging supplies. The PFN consists of two 8-cell lines connected in parallel. EEV CX1836A thyratrons are used as discharge switches. The PSpice simulation of the modulators using OrCAD release 9.1 made it possible to find appropriate parameters of RC circuits that reduce high-frequency ringing of the pulse transformer primary voltage. In order to improve pulse top flatness (originally {+-}3%), new coils were built and installed. The coils allow discrete tuning of pulse waveforms by changing the amount of used turns. The advantage of two parallel-line PFN configurations was also used. An equivalent method using a low-voltage generator was used for PFN fine tuning.

  1. Advanced Modeling Environments 1 Daniel Dolk

    E-print Network

    Kimbrough, Steven Orla

    Section 3.1) and ty* *pically models are being developed by different teams. Various methods of model* *striction of the selection of model analysis methods applied to a particular case. Computer and analysis communities. Produced in the normal course * *of scientific and policy investigations, models

  2. Advanced Modeling Environments 1 Daniel Dolk

    E-print Network

    Kimbrough, Steven Orla

    and modeling lie at the core of scientific and policy research endeavors. Effective tools for management methods. Actually, each model has at least three distinct representations (see Section 3.1) and typically models are being developed by different teams. Various methods of model analysis often require a specific

  3. Agent-based Mission Modeling and Simulation

    Microsoft Academic Search

    Maarten Sierhuis; J. Clancey; Chin Seah; Alessandro Acquisti; David Bushnell; Bruce Damer; Nancy Dorighi; Larry Edwards; Lisa Faithorn; Lorenzo Flueckiger; Ron van Hoof; Anand Nandkumar; Christian Neukom; Mike Scott; Michael Sims; Roxana Wales; Shin-Ywan Wang; James Wood

    2006-01-01

    A simulation environment for agents is presented, enabling agent-based modeling and simulation of people, systems and robots in space exploration missions. The environment allows the analysis and design of mission operation work procedures, communications and interactions between people and systems, co-located or distributed on Earth and in space. The MODAT (Mission Operations Design and Analysis Toolkit) is the integration of

  4. CAR REGISTRATION SIMULATION MODEL IN GCC COUNTRY

    Microsoft Academic Search

    Shamsuddin Ahmed

    Car registration and inspection simulation experiment to analyze business functions of the traffic department in Al-Ain city in United Arab Emirates (UAE) is reported. The car registration is managed by a government organization in association with a private network service company that looks after the inspection service. A visual AweSim car registration simulation model is developed from workflow viewpoint. The

  5. Modeling and simulation of organic solar cells

    Microsoft Academic Search

    Liming Liu; Guangyong Li

    2010-01-01

    We present our investigation of organic solar cells by modeling and simulation after numerically solving Poisson and continuity equations that describe the electric property of semiconductors. Specifically, simulations reveal that Langevin type recombination, which describes the loss mechanism in pristine materials with low mobility, is not proper to predict the performance of BHJ organic solar cells and will lead counterintuitive

  6. Modeling and simulating electronic textile applications

    Microsoft Academic Search

    Thomas Martin; Mark Jones; Joshua Edmison; Tanwir Sheikh; Zahi Nakad

    2004-01-01

    This paper describes our design of a simulation environment for electronic textiles (e-textiles) and our experiences with that environment. This simulation environment, based upon Ptolemy II, enables us to model a diverse range of areas related to the design of electronic textiles, including the physical environment they will be used in, the behavior of the sensors incorporated into the fabric,

  7. KU-Band rendezvous radar performance computer simulation model

    Microsoft Academic Search

    J. W. Griffin

    1980-01-01

    The preparation of a real time computer simulation model of the KU band rendezvous radar to be integrated into the shuttle mission simulator (SMS), the shuttle engineering simulator (SES), and the shuttle avionics integration laboratory (SAIL) simulator is described. To meet crew training requirements a radar tracking performance model, and a target modeling method were developed. The parent simulation\\/radar simulation

  8. The aircraft movement simulation model

    Microsoft Academic Search

    Michel A. Thomet

    1983-01-01

    The following paragraphs describe a computer program for simulating the movements of aircraft on the apron, taxiways, and runways of an airport. The purpose of this program is to enable the airport planner to evaluate the performance of a given airport layout from an operational point of view. Likewise, he can compare alternative layouts, investigate the impact of a change

  9. Real-time, Non-linear, Dynamic Simulation in Teaching Structures: Elementary to Advanced

    Microsoft Academic Search

    Kirk Martini

    The paper describes a project to develop software and teaching methods which employ real-time non-linear dynamic structural simulation in topics ranging from introductory statics to advanced steel design and earthquake engineering. The software is called Arcade and its computation method is based on a physics engine, a method which has been widely applied in computer games. The physics engine approach

  10. Advances in the simulation and automated measurement of well-sorted granular material

    E-print Network

    Advances in the simulation and automated measurement of well-sorted granular material: 2. Direct on the structure of well-sorted natural granular material (sediment), new methods are described for automated) with and without apparent void fraction; and 2) mean particle size in material with void fraction. A variety

  11. Battery Performance of ADEOS (Advanced Earth Observing Satellite) and Ground Simulation Test Results

    NASA Technical Reports Server (NTRS)

    Koga, K.; Suzuki, Y.; Kuwajima, S.; Kusawake, H.

    1997-01-01

    The Advanced Earth Observing Satellite (ADEOS) is developed with the aim of establishment of platform technology for future spacecraft and inter-orbit communication technology for the transmission of earth observation data. ADEOS uses 5 batteries, consists of two packs. This paper describes, using graphs and tables, the ground simulation tests and results that are carried to determine the performance of the ADEOS batteries.

  12. Type Ia supernovae: advances in large scale simulation M. Zingale,2

    E-print Network

    Bell, John B.

    Type Ia supernovae: advances in large scale simulation H. Ma,1 M. Zingale,2 S. E. Woosley,1 A. J stars as Type Ia supernovae. Since the outcome is sensitive to where the nuclear runaway ignites, three of the turbulence in the explosion studies. 1. Introduction Type Ia supernovae (SN Ia) happen when a white dwarf

  13. WinSRFR: Current Advances in Software for Surface Irrigation Simulation and Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant advances have been made over the last decade in the development of software for surface irrigation analysis. WinSRFR is an integrated tool that combines unsteady flow simulation with tools for system evaluation/parameter estimation, system design, and for operational optimization. Ongoi...

  14. A Flight Software Development and Simulation Framework for Advanced Space Systems

    E-print Network

    compo- nents. These services help to reduce the complexity of managing software interfaces. The hard.1.3 Communications Complexity in Software Systems . . . . . . . . . . 18 1.2 Middleware for Complexity ManagementA Flight Software Development and Simulation Framework for Advanced Space Systems John P. Enright

  15. [Research advances in simulating land water-carbon coupling].

    PubMed

    Liu, Ning; Sun, Peng-Sen; Liu, Shi-Rong

    2012-11-01

    The increasing demand of adaptive management of land, forest, and water resources under the background of global change and water resources crisis has promoted the comprehensive study of coupling ecosystem water and carbon cycles and their restrictive relations. To construct the water-carbon coupling model and to approach the ecosystem water-carbon balance and its interactive response mechanisms under climate change at multiple spatiotemporal scales is nowadays a major concern. After reviewing the coupling relationships of water and carbon at various scales, this paper explored the implications and estimation methods of the key processes and related parameters of water-carbon coupling, the construction of evapotranspiration model at large scale based on RS, and the importance of this model in water-carbon coupling researches. The applications of assimilative multivariate data in water-carbon coupling researches under future climate change scenarios were also prospected. PMID:23431808

  16. Advances in finite element simulations of elastosonography for breast lesion detection.

    PubMed

    Celi, Simona; Di Puccio, Francesca; Forte, Paola

    2011-08-01

    Among the available tools for the early diagnosis of breast cancer, the elastographic technique based on ultrasounds has many advantages such as the noninvasive measure, the absence of ionizing effects, the high tolerability by patients, and the wide diffusion of the ecographic machines. However this diagnostic procedure is strongly affected by many subjective factors and is considered not reliable enough even to reduce the number of biopsies used to identify the nature of lesions. Therefore in the literature experimental and numerical simulations on physical and virtual phantoms are presented to test and validate procedures and algorithms and to interpret elastosonographic results. In this work, first a description of the elastographic technique and a review of the principal finite element (FE) models are provided and second diagnostic indexes employed to assess the nature of a lump mass are presented. As advances in FE simulations of elastosonography, axisymmetric phantom, and anthropomorphic models are described, which, with respect to the literature, include some features of breast mechanics. In particular deterministic analyses were used to compare the various details of virtual elastograms and also to investigate diagnostic indexes with respect to the regions where strains were considered. In order to improve the reliability of the elastosonographic procedure, univariate and multivariate sensitivity analyses, based on a probabilistic FE approach, were also performed to identify the parameters that mostly influence the deformation contrast between healthy and cancerous tissues. Moreover, synthetic indicators of the strain field, such as the strain contrast coefficient, were evaluated in different regions of interest in order to identify the most suitable for lesion type assessment. The deterministic analyses show that the malignant lesion is characterized by a uniform strain inside the inclusion due to the firmly bonding condition, while in the benign inclusion (loosely bonded) a strain gradient is observed independently from the elastic modulus contrast. The multivariate analyses reveal that the strain contrast depends linearly on the relative stiffness between the lesion and the healthy tissue and not linearly on the interface friction coefficient. The anthropomorphic model shows other interesting features, such as the layer or curvature effects, which introduce difficulties in selecting a reference region for strain assessment. The results show that a simple axisymmetric model with linear elastic material properties can be suitable to simulate the elastosonographic procedure although the breast curvature and layer distinction play a significant role in the strain assessment. PMID:21950899

  17. Regional model simulations of New Zealand climate

    Microsoft Academic Search

    James A. Renwick; Jack J. Katzfey; Kim C. Nguyen; John L. McGregor

    1998-01-01

    Simulation of New Zealand climate is examined through the use of a regional climate model nested within the output of the Commonwealth Scientific and Industrial Research Organisation nine-level general circulation model (GCM). R21 resolution GCM output is used to drive a regional model run at 125 km grid spacing over the Australasian region. The 125 km run is used in

  18. Computer simulations and physical modelling of erosion

    E-print Network

    Franklin, W. Randolph

    Computer simulations and physical modelling of erosion C.S. Stuetzle, J. Gross, Z. Chen, B. Cutler in 2 disciplines. 2 / 10 #12;Problem and goals Validation of Erosion Models for Levee Overtopping Levee terrain, a.k.a. soil, · better modeling of local erosion in terrain and earthen structures such as levees

  19. Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Metscher, Jonathan F.; Lewandowski, Edward J.

    2015-01-01

    Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and also compared against each other. Results show both models can be tuned to achieve results within 7 of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

  20. Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Metscher, Jonathan F.; Lewandowski, Edward

    2014-01-01

    Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and compared against each other. Results show both models can be tuned to achieve results within 7% of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

  1. MODELING, SIMULATION AND OPTIMIZATION OF GROUND SOURCE

    E-print Network

    MODELING, SIMULATION AND OPTIMIZATION OF GROUND SOURCE HEAT PUMP SYSTEMS By MUHAMMAD HAIDER KHAN AND OPTIMIZATION OF GROUND SOURCE HEAT PUMP SYSTEMS Thesis Approved..................................................................................................................... 1 1.1 Overview of Ground Source Heat Pump Systems.............................................. 1 1

  2. Mathematical Model Development and Simulation Support

    NASA Technical Reports Server (NTRS)

    Francis, Ronald C.; Tobbe, Patrick A.

    2000-01-01

    This report summarizes the work performed in support of the Contact Dynamics 6DOF Facility and the Flight Robotics Lab at NASA/ MSFC in the areas of Mathematical Model Development and Simulation Support.

  3. Theory, modeling, and simulation annual report, 1992

    SciTech Connect

    Not Available

    1993-05-01

    This report briefly discusses research on the following topics: development of electronic structure methods; modeling molecular processes in clusters; modeling molecular processes in solution; modeling molecular processes in separations chemistry; modeling interfacial molecular processes; modeling molecular processes in the atmosphere; methods for periodic calculations on solids; chemistry and physics of minerals; graphical user interfaces for computational chemistry codes; visualization and analysis of molecular simulations; integrated computational chemistry environment; and benchmark computations.

  4. Interactive Visualization to Advance Earthquake Simulation LOUISE H. KELLOGG,1

    E-print Network

    Billen, Magali I.

    with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth and geophysical data available from field observations. Key words: Interactive visualization, virtual reality's surface and interior. Virtual mapping tools allow virtual ``field studies'' in inaccessible regions

  5. Advancements in hardware-in-the-loop simulations at the U.S. Army Aviation and Missile Command

    NASA Astrophysics Data System (ADS)

    Buford, James A.; Jolly, Alexander C.; Mobley, Scott B.; Sholes, William J.

    2000-07-01

    A greater awareness of and increased interest in the use of modeling and simulation (M&S) has been demonstrated at many levels within the Department of Defense (DoD) and all the Armed Services agencies in recent years. M&S application is regarded as a viable means of lowering the life cycle costs of missile defense and tactical missile weapon system acquisition beginning with studies of new concepts of war-fighting through user training and post-deployment support. The Aviation and Missile Research, Engineering, and Development Center (AMRDEC) of the U.S. Army Aviation and Missile Command (AMCOM) has an extensive history of applying all types of M&S to weapons system development and has been a particularly strong advocate of hardware-in-the-loop (HWIL) simulation and test for many years. Over the past 40 years AMRDEC has developed and maintained the Advanced Simulation Center (ASC) which provides world-class, high fidelity, specific and dedicated HWIL simulation and test capabilities for the Army's missile defense and tactical missile program offices in both the infrared and radio frequency sensor domains. The ASC facility uses M&S to conduct daily HWIL missile simulations and tests to support flight tests, missile/system development, independent verification and validation of weapon system embedded software and simulations, and missile/system performance against current and future threat environments. This paper describes the ASC role, recaps the past year, describes the HWIL components and advancements, and outlines the path-ahead for the ASC in terms of both missile and complete system HWIL simulations and test with a focus on the imaging infrared systems.

  6. Adversary Modeling and Simulation in Cyber Warfare

    Microsoft Academic Search

    Samuel N. Hamilton; Wendy L. Hamilton

    2008-01-01

    Modeling and simulation provide many excellent benefits in preparation for successful cyber operations. Whether used for creating\\u000a realistic training environments, testing new cyber warfare techniques, or predicting possible adversary actions, it is critical\\u000a for such simulations to take into account the possibility of an active cyber adversary, able to adapt its plans to network\\u000a conditions. Without realtime high fidelity modeling

  7. Application of Chebyshev polynomial to simulated modeling

    NASA Astrophysics Data System (ADS)

    Chi, Hai-Hong; Li, Dian-Pu

    2006-12-01

    Chebyshev polynomial is widely used in many fields, and used usually as function approximation in numerical calculation. In this paper, Chebyshev polynomial expression of the propeller properties across four quadrants is given at first, then the expression of Chebyshev polynomial is transformed to ordinary polynomial for the need of simulation of propeller dynamics. On the basis of it, the dynamical models of propeller across four quadrants are given. The simulation results show the efficiency of mathematical model.

  8. Verification validation and accreditation of simulation models

    Microsoft Academic Search

    Osman Balci

    1997-01-01

    This paper presents guidelines for conducting verifica- tion, validation and accreditation (VV&A) of simulation models. Fifteen guiding principles are introduced to help the researchers, practitioners and managers better com- prehend what VV&A is all about. The VV&A activities are described in the modeling and simulation life cycle. A taxonomy of more than 77 V&V techniques is provided to assist simulationists

  9. Advanced battery modeling using neural networks

    E-print Network

    Arikara, Muralidharan Pushpakam

    1993-01-01

    battery models are available today that can accurately predict the performance of the battery system. This thesis presents a modeling technique for batteries employing neural networks. The advantage of using neural networks is that the effect of any...

  10. Advances in Energy Systems Modeling and Control

    Microsoft Academic Search

    Andrew Alleyne; Bryan Rasmussen

    2007-01-01

    This paper gives an overview of dynamic modeling for energy systems related to vapor compression cycles. Basic components of these systems are described and equations of state are developed. For the heat exchangers, these equations of state are based on a moving boundary models. A reduction of system model order, and insight into primary dynamic modes, is presented. These reduced

  11. Advanced CFD modelling of pulverised biomass combustion

    Microsoft Academic Search

    S. Zahirovic; R. Scharler; I. Obernberger

    In this paper, the development and application of a CFD model for pulverised biomass combustion is presented. As a first step, the Discrete Phase Model (DPM) of the commercial CFD software FLUENT, originally developed for the combustion of pulverised coal, was investigated regarding its capability to predict pulverised biomass combustion. Based on these investigations, a more detailed sub- model for

  12. Minimum-complexity helicopter simulation math model

    NASA Technical Reports Server (NTRS)

    Heffley, Robert K.; Mnich, Marc A.

    1988-01-01

    An example of a minimal complexity simulation helicopter math model is presented. Motivating factors are the computational delays, cost, and inflexibility of the very sophisticated math models now in common use. A helicopter model form is given which addresses each of these factors and provides better engineering understanding of the specific handling qualities features which are apparent to the simulator pilot. The technical approach begins with specification of features which are to be modeled, followed by a build up of individual vehicle components and definition of equations. Model matching and estimation procedures are given which enable the modeling of specific helicopters from basic data sources such as flight manuals. Checkout procedures are given which provide for total model validation. A number of possible model extensions and refinement are discussed. Math model computer programs are defined and listed.

  13. Modeling of transformers using circuit simulators

    NASA Astrophysics Data System (ADS)

    Archer, W. E.; Deveney, M. F.; Nagel, R. L.

    Transformers of two different designs, an unencapsulated pot core and an encapsulated toroidal core, have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim's PSPICE and Anology's SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.

  14. A simulation model of an insect population

    NSDL National Science Digital Library

    0000-00-00

    An insect life table simulation developed by Hein Bijlmakers. The above URL gets you to the introduction of the simulation model where various aspects of an insect population dynamics are explained. The link to the simulation brings you to the model itself with a myriad of variables including population development; egg; larval; pupal and adult mortality by parasitoids and predators amongst others. This is a great tool to investigate various aspects of insect population dynamics allowing one to investigate the impact of a number of variables on a population and may help students understand the function of insect life tables. Up to 40 generations can be iterated.

  15. Advanced AEM by Comprehensive Analysis and Modeling of System Drift

    NASA Astrophysics Data System (ADS)

    Schiller, Arnulf; Klune, Klaus; Schattauer, Ingrid

    2010-05-01

    The quality of the assessment of risks outgoing from environmental hazards strongly depends on the spatial and temporal distribution of the data collected in a survey area. Natural hazards generally emerge from wide areas as it is in the case of volcanoes or land slides. Conventional surface measurements are restricted to few lines or locations and often can't be conducted in difficult terrain. So they only give a spatial and temporary limited data set and therefore limit the reliability of risk analysis. Aero-geophysical measurements potentially provide a valuable tool for completing the data set as they can be performed over a wide area, even above difficult terrain within a short time. A most desirable opportunity in course of such measurements is the ascertainment of the dynamics of such potentially hazardous environmental processes. This necessitates repeated and reproducible measurements. Current HEM systems can't accomplish this adequately due to their system immanent drift and - in some cases - bad signal to noise ratio. So, to develop comprising concepts for advancing state of the art HEM-systems to a valuable tool for data acquisition in risk assessment or hydrological problems, different studies have been undertaken which form the contents of the presented work conducted in course of the project HIRISK (Helicopter Based Electromagnetic System for Advanced Environmental Risk Assessment - FWF L-354 N10, supported by the Austrian Science Fund). The methodology is based upon two paths: A - Comprehensive experimental testing on an existing HEM system serving as an experimental platform. B - The setup of a numerical model which is continuously refined according to the results of the experimental data. The model then serves to simulate the experimental as well as alternative configurations and to analyze them subject to their drift behavior. Finally, concepts for minimizing the drift are derived and tested. Different test series - stationary on ground as well as in flight - show a clear correlation between the drift in raw voltage data and temperatures of critical system components, especially in the transmitter and receiver sections. Further, the correlation with air pressure, humidity, structure geometry and static electricity has been investigated. It shows that in case of a tuned system the dependency of signal phase and amplitude on system component temperatures prevails by far and can explain most of the system drift in the voltage domain. Post-processing for compensating for the drift of HEM-data is done by two different approaches: In the first, temperature dependent transfer functions of the transmitter- and receiver section are modeled on the basis of system temperature data and a correction is derived. In an advanced approach the drift of the system is analyzed by multivariate analysis including a broader set of data (HEM-signal, transmitter-reference signal, system temperatures, humidity, air pressure, height, dynamic loads) and based on an extended model. It proves that such an analysis is able to identify residual drift sources. As a result an integrated modeling scheme is depicted which enables a better separation of signal variations caused by the system or by changes in the measurement geometry from signal variations caused by the source distribution in the ground if critical system parameters are incorporated.

  16. Numerical simulation and experimental verification of melt front advancements in coinjection molding process

    SciTech Connect

    Chen, S.C.; Hsu, K.F. [Chung Yuan Univ., Chung-Li (Taiwan, Province of China). Mechanical Engineering Dept.

    1995-10-01

    Experimental studies of polymer melt flow in the mold filling stage of the coinjection molding process have been carried out using sequential injection of transparent and colored polystyrene resin. Simulations are also developed to predict the melt front advancements of both skin and core melts. A control volume/finite element method employed within each grid layer of the gapwise direction is applied to trace the melt front advancements for both skin and core materials. Numerical simulations show reasonably good consistency with experimental results in both skin and core material distribution. However, the simulation accuracy can be improved further if edge effect is taken into account using the shape factor as a geometrical correction.

  17. Construction of dynamic stochastic simulation models using knowledge-based techniques

    NASA Technical Reports Server (NTRS)

    Williams, M. Douglas; Shiva, Sajjan G.

    1990-01-01

    Over the past three decades, computer-based simulation models have proven themselves to be cost-effective alternatives to the more structured deterministic methods of systems analysis. During this time, many techniques, tools and languages for constructing computer-based simulation models have been developed. More recently, advances in knowledge-based system technology have led many researchers to note the similarities between knowledge-based programming and simulation technologies and to investigate the potential application of knowledge-based programming techniques to simulation modeling. The integration of conventional simulation techniques with knowledge-based programming techniques is discussed to provide a development environment for constructing knowledge-based simulation models. A comparison of the techniques used in the construction of dynamic stochastic simulation models and those used in the construction of knowledge-based systems provides the requirements for the environment. This leads to the design and implementation of a knowledge-based simulation development environment. These techniques were used in the construction of several knowledge-based simulation models including the Advanced Launch System Model (ALSYM).

  18. Modeling and simulation of mobile satellite propagation

    NASA Technical Reports Server (NTRS)

    Barts, R. M.; Stutzman, Warren L.

    1992-01-01

    Mobile satellite systems are subject to severe fading due to blockage of the line-of-sight (LOS) path by roadside vegetation. A thorough understanding of the fading effects is necessary for the design of a reliable land mobile satellite system (LMSS). Analytical and empirical models are presented for predicting fade statistics for vegetative shadowing of mobile satellite terminals. A software simulator for generating simulated fade data is also presented. A physical model relating physical path parameters to propagation model parameters is presented, and results using the model are shown.

  19. Neural Network Modeling for Advanced Process Control Using Production Data

    Microsoft Academic Search

    Zubin N. Mevawalla; Gary S. May; Mark W. Kiehlbauch

    2011-01-01

    The fabrication of integrated circuits involves many unit processes, some linear and some non-linear, and each with multiple inputs and outputs. These complexities suggest that benefits could be derived from the development and implementa- tion of advanced process control tools and strategies. Empirical process models are one of these tools. In this research, sequential neural network models are developed to

  20. Recent advances in modeling nutrient utilization in ruminants1

    Microsoft Academic Search

    E. Kebreab; J. Dijkstra; A. Bannink

    2009-01-01

    Mathematical modeling techniques have been applied to study various aspects of the ruminant, such as rumen function, post-absorptive metabolism and product composition. This review focuses on advances made in modeling rumen fermentation and its associated rumen disorders, and energy and nutrient utilization and excretion with respect to environmental issues. Accurate prediction of fermentation stoichiometry has impact on estimating the type

  1. Input modeling: input modeling techniques for discrete-event simulations

    Microsoft Academic Search

    Lawrence Leemis

    2001-01-01

    Most discrete-event simulation models have stochastic elements that mimic the probabilistic nature of the system under consideration. A close match between the input model and the true underlying probabilistic mechanism associated with the system is required for successful input modeling. The general question considered here is how to model an element (e.g., arrival process, service times) in a discrete-event simulation

  2. Numerical simulation of the flow in wire-wrapped pin bundles: Effect of pin-wire contact modeling

    Microsoft Academic Search

    E. Merzari; W. D. Pointer; J. G. Smith; A. Tentner; P. Fischer

    The rapid advancement of numerical techniques and the availability of increasingly powerful supercomputers recently enabled scientists to use large eddy simulation (LES) to simulate numerically the flow in a full subassembly composed of wire-wrapped pins. Because of the extreme computational cost of such simulations, it was not possible to conduct a sensitivity case on the pin-wire interface modeling. Since such

  3. Carbon export algorithm advancements in models

    NASA Astrophysics Data System (ADS)

    Ça?lar Yumruktepe, Veli; Saliho?lu, Bar??

    2015-04-01

    The rate at which anthropogenic CO2 is absorbed by the oceans remains a critical question under investigation by climate researchers. Construction of a complete carbon budget, requires better understanding of air-sea exchanges and the processes controlling the vertical and horizontal transport of carbon in the ocean, particularly the biological carbon pump. Improved parameterization of carbon sequestration within ecosystem models is vital to better understand and predict changes in the global carbon cycle. Due to the complexity of processes controlling particle aggregation, sinking and decomposition, existing ecosystem models necessarily parameterize carbon sequestration using simple algorithms. Development of improved algorithms describing carbon export and sequestration, suitable for inclusion in numerical models is an ongoing work. Existing unique algorithms used in the state-of-the art ecosystem models and new experimental results obtained from mesocosm experiments and open ocean observations have been inserted into a common 1D pelagic ecosystem model for testing purposes. The model was implemented to the timeseries stations in the North Atlantic (BATS, PAP and ESTOC) and were evaluated with datasets of carbon export. Targetted topics of algorithms were PFT functional types, grazing and vertical movement of zooplankton, and remineralization, aggregation and ballasting dynamics of organic matter. Ultimately it is intended to feed improved algorithms to the 3D modelling community, for inclusion in coupled numerical models.

  4. Ray tracing simulation of 1-BM beamline at the Advanced Photon Source for polarization analyses of synchrotron optics

    NASA Astrophysics Data System (ADS)

    Kujala, Naresh; Macrander, Albert; Shi, Xianbo; Reininger, Ruben; Gao, Xuan; Burns, Clement

    2014-09-01

    In this paper, we present recent progress on polarization optics using the 1-BM beamline at the Advanced Photon Source, Argonne National Laboratory. Beamline 1-BM was recently repurposed for optics and detector testing. SHADOW software, a ray-tracing program for the simulation of optical systems of synchrotron radiation beamlines, is used to model the beamline. In this paper, we present optical ray-tracing studies for test set-ups that take advantage of the polarization variation of the bending magnet radiation above and below the horizontal plane of the beamline.

  5. Architecting a Simulation Framework for Model Rehosting

    NASA Technical Reports Server (NTRS)

    Madden, Michael M.

    2004-01-01

    The utility of vehicle math models extends beyond human-in-the-loop simulation. It is desirable to deploy a given model across a multitude of applications that target design, analysis, and research. However, the vehicle model alone represents an incomplete simulation. One must also replicate the environment models (e.g., atmosphere, gravity, terrain) to achieve identical vehicle behavior across all applications. Environment models are increasing in complexity and represent a substantial investment to re-engineer for a new application. A software component that can be rehosted in each application is one solution to the deployment problem. The component must encapsulate both the vehicle and environment models. The component must have a well-defined interface that abstracts the bulk of the logic to operate the models. This paper examines the characteristics of a rehostable modeling component from the perspective of a human-in-the-loop simulation framework. The Langley Standard Real-Time Simulation in C++ (LaSRS++) is used as an example. LaSRS++ was recently redesigned to transform its modeling package into a rehostable component.

  6. Virtual Cell modelling and simulation software environment.

    PubMed

    Moraru, I I; Schaff, J C; Slepchenko, B M; Blinov, M L; Morgan, F; Lakshminarayana, A; Gao, F; Li, Y; Loew, L M

    2008-09-01

    The Virtual Cell (VCell; http://vcell.org/) is a problem solving environment, built on a central database, for analysis, modelling and simulation of cell biological processes. VCell integrates a growing range of molecular mechanisms, including reaction kinetics, diffusion, flow, membrane transport, lateral membrane diffusion and electrophysiology, and can associate these with geometries derived from experimental microscope images. It has been developed and deployed as a web-based, distributed, client-server system, with more than a thousand world-wide users. VCell provides a separation of layers (core technologies and abstractions) representing biological models, physical mechanisms, geometry, mathematical models and numerical methods. This separation clarifies the impact of modelling decisions, assumptions and approximations. The result is a physically consistent, mathematically rigorous, spatial modelling and simulation framework. Users create biological models and VCell will automatically (i) generate the appropriate mathematical encoding for running a simulation and (ii) generate and compile the appropriate computer code. Both deterministic and stochastic algorithms are supported for describing and running non-spatial simulations; a full partial differential equation solver using the finite volume numerical algorithm is available for reaction-diffusion-advection simulations in complex cell geometries including 3D geometries derived from microscope images. Using the VCell database, models and model components can be reused and updated, as well as privately shared among collaborating groups, or published. Exchange of models with other tools is possible via import/export of SBML, CellML and MatLab formats. Furthermore, curation of models is facilitated by external database binding mechanisms for unique identification of components and by standardised annotations compliant with the MIRIAM standard. VCell is now open source, with its native model encoding language (VCML) being a public specification, which stands as the basis for a new generation of more customised, experiment-centric modelling tools using a new plug-in based platform. PMID:19045830

  7. A Visual Basic simulation software tool for performance analysis of a membrane-based advanced water treatment plant.

    PubMed

    Pal, P; Kumar, R; Srivastava, N; Chowdhury, J

    2014-02-01

    A Visual Basic simulation software (WATTPPA) has been developed to analyse the performance of an advanced wastewater treatment plant. This user-friendly and menu-driven software is based on the dynamic mathematical model for an industrial wastewater treatment scheme that integrates chemical, biological and membrane-based unit operations. The software-predicted results corroborate very well with the experimental findings as indicated in the overall correlation coefficient of the order of 0.99. The software permits pre-analysis and manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. It allows quick performance analysis of the whole system as well as the individual units. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for hazardous wastewater. PMID:23982824

  8. Advanced Information Technology in Simulation Based Life Cycle Design

    NASA Technical Reports Server (NTRS)

    Renaud, John E.

    2003-01-01

    In this research a Collaborative Optimization (CO) approach for multidisciplinary systems design is used to develop a decision based design framework for non-deterministic optimization. To date CO strategies have been developed for use in application to deterministic systems design problems. In this research the decision based design (DBD) framework proposed by Hazelrigg is modified for use in a collaborative optimization framework. The Hazelrigg framework as originally proposed provides a single level optimization strategy that combines engineering decisions with business decisions in a single level optimization. By transforming this framework for use in collaborative optimization one can decompose the business and engineering decision making processes. In the new multilevel framework of Decision Based Collaborative Optimization (DBCO) the business decisions are made at the system level. These business decisions result in a set of engineering performance targets that disciplinary engineering design teams seek to satisfy as part of subspace optimizations. The Decision Based Collaborative Optimization framework more accurately models the existing relationship between business and engineering in multidisciplinary systems design.

  9. Atmospheric model intercomparison project: Monsoon simulations

    SciTech Connect

    Sperber, K.R. [Lawrence Livermore National Lab., CA (United States). Program for Climate Model Diagnosis and Intercomparison; Palmer, T.N. [European Centre for Medium-Range Weather Forecasts, Reading (United Kingdom)

    1994-06-01

    The simulation of monsoons, in particular the Indian summer monsoon, has proven to be a critical test of a general circulation model`s ability to simulate tropical climate and variability. The Monsoon Numerical Experimentation Group has begun to address questions regarding the predictability of monsoon extremes, in particular conditions associated with El Nino and La Nina conditions that tend to be associated with drought and flood conditions over the Indian subcontinent, through a series of seasonal integrations using analyzed initial conditions from successive days in 1987 and 1988. In this paper the authors present an analysis of simulations associated with the Atmospheric Model Intercomparison Project (AMIP), a coordinated effort to simulate the 1979--1988 decade using standardized boundary conditions with approximately 30 atmospheric general circulation models. The 13 models analyzed to date are listed. Using monthly mean data from these simulations they have calculated indices of precipitation and wind shear in an effort to access the performance of the models over the course of the AMIP decade.

  10. GOING TO THE EXTREMES AN INTERCOMPARISON OF MODEL-SIMULATED HISTORICAL AND

    E-print Network

    Meehl, Gerald A.

    GOING TO THE EXTREMES AN INTERCOMPARISON OF MODEL-SIMULATED HISTORICAL AND FUTURE CHANGES Abstract. Projections of changes in climate extremes are critical to assessing the potential impacts of climate change on human and natural systems. Modeling advances now provide the opportunity of utilizing

  11. Estimating solar radiation for plant simulation models

    SciTech Connect

    Hodges, T.; French, V.; Leduc, S.

    1985-01-01

    Five algorithms producing daily solar radiation surrogates using daily temperatures and rainfall were evaluated using measured solar radiation data for seven U.S. locations. The algorithms were compared both in terms of accuracy of daily solar radiation estimates and terms of response when used in a plant growth simulation model (CERES-wheat). Requirements for accuracy of solar radiation for plant growth simulation models are discussed. One algorithm is recommended as being best suited for use in these models when neither measured nor satellite estimated solar radiation values are available.

  12. URC Fuzzy Modeling and Simulation of Gene Regulation

    SciTech Connect

    Sokhansanj, B A; Fitch, J P

    2001-05-01

    Recent technological advances in high-throughput data collection give biologists the ability to study increasingly complex systems. A new methodology is needed to develop and test biological models based on experimental observations and predict the effect of perturbations of the network (e.g. genetic engineering, pharmaceuticals, gene therapy). Diverse modeling approaches have been proposed, in two general categories: modeling a biological pathway as (a) a logical circuit or (b) a chemical reaction network. Boolean logic models can not represent necessary biological details. Chemical kinetics simulations require large numbers of parameters that are very difficult to accurately measure. Based on the way biologists have traditionally thought about systems, we propose that fuzzy logic is a natural language for modeling biology. The Union Rule Configuration (URC) avoids combinatorial explosion in the fuzzy rule base, allowing complex system models. We demonstrate the fuzzy modeling method on the commonly studied lac operon of E. coli. Our goal is to develop a modeling and simulation approach that can be understood and applied by biologists without the need for experts in other fields or ''black-box'' software.

  13. Realistic model for battlefield fire plume simulation

    Microsoft Academic Search

    Dorothy Bruce

    1991-01-01

    Real battlefields are very messy places which may contain burning vehicles, vegetation, or buildings and with atmospheres containing dust and smoke clouds. Realistic scene simulation for system evaluation must therefore also contain these same elements. A model has been developed to generate realistic images of fire plumes from burning military vehicles. Model output includes transmittance through the plume and radiance

  14. Modeling and simulation for control design

    Microsoft Academic Search

    Eric Salter; Chris LaVigna; Mike Mattice; Mary Devito; Robert Testa

    1998-01-01

    This paper documents the use of recently developed symbolic software for modeling of a US Army M113 armoured personnel carrier and numerical simulation of the generated nonlinear ordinary differential equations of motion. A brief discussion of the symbolic software used for modeling, analysis, and control system design of multiple body systems is presented. This software is used to create a

  15. Verifying and validating a simulation model

    Microsoft Academic Search

    Anbin Hu; Ye San; Zicai Wang

    2001-01-01

    This paper presents the verification and validation (V&V) of simulation model with the emphasis on the possible modification. Based on the analysis, a new framework is proposed, and new terms are defined. An example is employed to demonstrate how the framework and terms related are used in verifying and validating an existing model.

  16. Modeling and simulation of film blowing process

    E-print Network

    Mayavaram, Ravisankar S.

    2005-08-29

    . In this dissertation, a transient, axisymmetric, nonisothermal, viscoelastic model is developed to simulate the process, and it is solved using finite element method. Material behavior of polymer melt is described using a modified Phan-Thien-Tanner model in the liquid...

  17. Multiscale Numerical Models for Simulation of Radiation Events in Semiconductor Devices

    Microsoft Academic Search

    Alexander I. Fedoseyev; Marek Turowski; Ashok Raman; Michael L. Alles; Robert A. Weller

    2008-01-01

    This paper describes the new CFDRC mixed-mode simulator which combines multiscale 3D Technology Computer Aided Design (TCAD)\\u000a device models (fluid carrier transport and nuclear ion track impact), and advanced compact transistors models. Key features\\u000a include an interface and 3D adaptive meshing to allow simulations of single event radiation effects with nuclear reactions\\u000a and secondary particles computed by Vanderbilt’s MRED\\/Geant4 tools.

  18. Regional model simulations of New Zealand climate

    NASA Astrophysics Data System (ADS)

    Renwick, James A.; Katzfey, Jack J.; Nguyen, Kim C.; McGregor, John L.

    1998-03-01

    Simulation of New Zealand climate is examined through the use of a regional climate model nested within the output of the Commonwealth Scientific and Industrial Research Organisation nine-level general circulation model (GCM). R21 resolution GCM output is used to drive a regional model run at 125 km grid spacing over the Australasian region. The 125 km run is used in turn to drive a simulation at 50 km resolution over New Zealand. Simulations with a full seasonal cycle are performed for 10 model years. The focus is on the quality of the simulation of present-day climate, but results of a doubled-CO2 run are discussed briefly. Spatial patterns of mean simulated precipitation and surface temperatures improve markedly as horizontal resolution is increased, through the better resolution of the country's orography. However, increased horizontal resolution leads to a positive bias in precipitation. At 50 km resolution, simulated frequency distributions of daily maximum/minimum temperatures are statistically similar to those of observations at many stations, while frequency distributions of daily precipitation appear to be statistically different to those of observations at most stations. Modeled daily precipitation variability at 125 km resolution is considerably less than observed, but is comparable to, or exceeds, observed variability at 50 km resolution. The sensitivity of the simulated climate to changes in the specification of the land surface is discussed briefly. Spatial patterns of the frequency of extreme temperatures and precipitation are generally well modeled. Under a doubling of CO2, the frequency of precipitation extremes changes only slightly at most locations, while air frosts become virtually unknown except at high-elevation sites.

  19. Modeling of advanced ECLSS/ARS with ASPEN

    NASA Technical Reports Server (NTRS)

    Kolodney, M.; Lange, K. E.; Edeen, M. A.

    1991-01-01

    System-level ASPEN models were developed for the CO2 partial reduction subsystem and a bioregenerative life support subsystem (BRLSS). The individual component and subsystem models were integrated into three different system-level atmospheric revitalization subsystem (ARS) models: baseline physico-chemical, BRLSS, and partial reduction of Martian CO2. The Aspen models were based on FORTRAN interfaces necessary for integration with another program, G189A, to perform quasi-transient modeling. Detailed reactor models were prepared for the two CO2 reduction reactors (Bosch and Advanced Carbon Formation), and the low-temperature trace contaminant oxidation reactor.

  20. Power electronics system modeling and simulation

    SciTech Connect

    Lai, Jih-Sheng

    1994-12-31

    This paper introduces control system design based softwares, SIMNON and MATLAB/SIMULINK, for power electronics system simulation. A complete power electronics system typically consists of a rectifier bridge along with its smoothing capacitor, an inverter, and a motor. The system components, featuring discrete or continuous, linear or nonlinear, are modeled in mathematical equations. Inverter control methods,such as pulse-width-modulation and hysteresis current control, are expressed in either computer algorithms or digital circuits. After describing component models and control methods, computer programs are then developed for complete systems simulation. Simulation results are mainly used for studying system performances, such as input and output current harmonics, torque ripples, and speed responses. Key computer programs and simulation results are demonstrated for educational purposes.

  1. Dilatation-dissipation corrections for advanced turbulence models

    Microsoft Academic Search

    David C. Wilcox

    1992-01-01

    This paper analyzes dilatation-dissipation based compressibility corrections for advanced turbulence models. Numerical computations verify that the dilatation-dissipation corrections devised by Sarkar and Zeman greatly improve both the k-omega and k-epsilon model predicted effect of Mach number on spreading rate. However, computations with the k-gamma model also show that the Sarkar\\/Zeman terms cause an undesired reduction in skin friction for the

  2. Modeling and simulation of PCM-enhanced facade systems

    NASA Astrophysics Data System (ADS)

    Al-Saadi, Saleh Nasser

    Building facade contributes to the overall architectural aesthetic but can be utilized for heat storage when proper systems are incorporated. Latent heat storage such as using a phase change material (PCM) gains growing attentions recently due to its ability of storing significant thermal energy within a small volume, making it one of most promising technologies for developing energy efficient buildings. This research is focused on modeling and simulation of PCM when integrated into advanced facade systems. The study first reviews the different mathematical modeling methods generally used for PCM's simulations. It categorizes the PCM's numerical models that are implemented for standalone facade systems. The study then evaluates the PCM's models that are integrated into whole building simulation tools such as EnergyPlus, TRNSYS, ESPr etc. It is revealed that the heat capacity method is mostly used in programs, despite its limitations on time and spatial resolutions. Therefore, alternative numerical models are investigated to overcome the above constrains and limitations in current PCM's simulation practice. Eight potential computational models based on a fully implicit finite volume method are developed in MATLAB/SIMULINK environment, validated using experimental results from the literature and verified against well-known building simulation programs. A linearized enthalpy method with hybrid correction scheme is proposed and validated in this work as an improvement to the existing numerical schemes for implementation into building simulation tools. Through sensitivity analysis achieved by varying the PCM thermal properties, the models have been analyzed for their computational efficiency and prediction accuracy. Some models are found sensitive to melting range of PCM, for example heat capacity method, but less sensitive to the variations of latent heat. Among the correction schemes, the non-iterative scheme is inaccurate due to the significant temperature spikes when PCM changes a state. The iterative and the hybrid correction schemes are computationally efficient and less sensitive to variations of PCM's thermal properties. Hence, these two schemes can potentially be implemented for modeling PCM instead of existing slow and unstable numerical algorithms. Based on this conclusion, a library of modules capable of modeling Advanced Facade Systems, entitled "AdvFacSy" toolbox, is developed in SIMULINK GUI environment. The toolbox can be easily used to evaluate innovative advanced facade systems with and without PCM. Using this toolbox, two PCM-enhanced facade designs are evaluated and general conclusions have been drawn. Using a novel coupling methodology, several modules from the toolbox are then fully integrated into TRNSYS; a whole-building simulation tool. In addition, a standard TRNSYS module, Type-285, is specifically developed under this research work for modeling multilayer wall with/without PCM. A typical residential building with PCM-embedded walls is analyzed under representative US climates. It is concluded that PCM poorly performs when it is exposed to natural environmental conditions. However, the performance of PCM has indeed been enhanced when activated using other passive strategies.

  3. Phenomenological Modeling of Infrared Sources: Recent Advances

    NASA Technical Reports Server (NTRS)

    Leung, Chun Ming; Kwok, Sun (Editor)

    1993-01-01

    Infrared observations from planned space facilities (e.g., ISO (Infrared Space Observatory), SIRTF (Space Infrared Telescope Facility)) will yield a large and uniform sample of high-quality data from both photometric and spectroscopic measurements. To maximize the scientific returns of these space missions, complementary theoretical studies must be undertaken to interpret these observations. A crucial step in such studies is the construction of phenomenological models in which we parameterize the observed radiation characteristics in terms of the physical source properties. In the last decade, models with increasing degree of physical realism (in terms of grain properties, physical processes, and source geometry) have been constructed for infrared sources. Here we review current capabilities available in the phenomenological modeling of infrared sources and discuss briefly directions for future research in this area.

  4. Development of NASA's Models and Simulations Standard

    NASA Technical Reports Server (NTRS)

    Bertch, William J.; Zang, Thomas A.; Steele, Martin J.

    2008-01-01

    From the Space Shuttle Columbia Accident Investigation, there were several NASA-wide actions that were initiated. One of these actions was to develop a standard for development, documentation, and operation of Models and Simulations. Over the course of two-and-a-half years, a team of NASA engineers, representing nine of the ten NASA Centers developed a Models and Simulation Standard to address this action. The standard consists of two parts. The first is the traditional requirements section addressing programmatics, development, documentation, verification, validation, and the reporting of results from both the M&S analysis and the examination of compliance with this standard. The second part is a scale for evaluating the credibility of model and simulation results using levels of merit associated with 8 key factors. This paper provides an historical account of the challenges faced by and the processes used in this committee-based development effort. This account provides insights into how other agencies might approach similar developments. Furthermore, we discuss some specific applications of models and simulations used to assess the impact of this standard on future model and simulation activities.

  5. Recent advances in modeling precession-nutation

    NASA Astrophysics Data System (ADS)

    Dehant, V.; Lambert, S.; Folgueira, M.; Koot, L.; Rambaux, N.

    2008-04-01

    Nutations are computed from modeling the gravitational forcing acting on the Earth from the Moon, the Sun and, to a minor extend, the other planets of the Solar system, and from modeling the interior of the Earth. One computes the Earth response to the gravitational forcing and then adds the geophysical effects from the surface liquid layers (atmosphere and ocean). The models for the interior of the Earth generally consider the existence of a liquid core, of a solid deformable inner core, and of a solid deformable inelastic mantle; the boundaries between the core and the inner core (ICB for Inner Core Boundary) and the core and the mantle (CMB for Core-Mantle Boundary) are flattened and can deform; the coupling mechanisms between the inner core, the outer core, and the mantle involve inertial coupling, gravitational coupling, pressure coupling, electromagnetic coupling, and viscous coupling. The last adopted model by the IAU and the IUGG, the so-called MHB2000 model from Mathews et al. (2002), considers all these coupling mechanisms except the viscous coupling, which is further considered in Guo et al. (2004). The rigid Earth nutations that are considered for this adopted model are those of Souchay et al. (1999). In the present paper we concentrate on the steps performed within the group related to the Royal Observatory of Belgium, toward the next decimal of nutation theory and observation. In particular, we examine the improvements on observations, on atmospheric and oceanic contributions to nutation (for the free and forced nutations), and on the computation of dissipative and excitation mechanisms for nutation.

  6. Modeling Innovations Advance Wind Energy Industry

    NASA Technical Reports Server (NTRS)

    2009-01-01

    In 1981, Glenn Research Center scientist Dr. Larry Viterna developed a model that predicted certain elements of wind turbine performance with far greater accuracy than previous methods. The model was met with derision from others in the wind energy industry, but years later, Viterna discovered it had become the most widely used method of its kind, enabling significant wind energy technologies-like the fixed pitch turbines produced by manufacturers like Aerostar Inc. of Westport, Massachusetts-that are providing sustainable, climate friendly energy sources today.

  7. Electronic International Journal: Advanced Modeling and Optimization

    NSDL National Science Digital Library

    This free, refereed journal is published between two and three times each year. It focuses on computational methods, algorithms, and applications related to modeling and optimization. The papers are quite diverse in topic, since many scientific and engineering disciplines fall within the journal's scope. The second volume of 2003 includes a paper on iris recognition for biometric security, as well as a paper that presents an "Economic Order Quantity" model for perishable goods. Each regular volume is fairly modest in size, averaging about four papers; however, a special issue on financial optimization published in 2002 was significantly longer.

  8. Hot-bench simulation of the active flexible wing wind-tunnel model

    NASA Technical Reports Server (NTRS)

    Buttrill, Carey S.; Houck, Jacob A.

    1990-01-01

    Two simulations, one batch and one real-time, of an aeroelastically-scaled wind-tunnel model were developed. The wind-tunnel model was a full-span, free-to-roll model of an advanced fighter concept. The batch simulation was used to generate and verify the real-time simulation and to test candidate control laws prior to implementation. The real-time simulation supported hot-bench testing of a digital controller, which was developed to actively control the elastic deformation of the wind-tunnel model. Time scaling was required for hot-bench testing. The wind-tunnel model, the mathematical models for the simulations, the techniques employed to reduce the hot-bench time-scale factors, and the verification procedures are described.

  9. Computational Modeling for Fretting Simulation

    Microsoft Academic Search

    Yasuyuki Ishimaru; Keiji Mashimo; Kyota Susai; Yingchao Fu; Anlin Wang

    2009-01-01

    As the number of wire circuits used in automobiles increases, larger force is required to mate connectors. In order to reduce wire assembling cost, connectors with low insertion force are desired. This may, however, result in fretting problems in electric contacts of terminals. To understand the mechanism of this failure, computational modeling is believed to be beneficial. The authors have

  10. Advanced chemical mechanisms for acid deposition modeling

    Microsoft Academic Search

    W. R. Stockwell; X. Tang

    1987-01-01

    Atmospheric chemistry is of concern to both policy-makers and scientists because atmospheric transformation rates determine the extent to which reductions in the emissions of sulfur and nitrogen oxides will in fact reduce acid deposition. Policy decisions should be based upon solid science, thus a chemical mechanism for a regional acid deposition model must incorporate all significant chemical reactions. The gas-phase

  11. Advances in Swine Biomedical Model Genomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The swine has been a major biomedical model species, for transplantation, heart disease, allergies and asthma, as well as normal neonatal development and reproductive physiology. Swine have been used extensively for studies of infectious disease processes and analyses of preventative strategies, inc...

  12. Smart Engines Via Advanced Model Based Controls

    SciTech Connect

    Allain, Marc

    2000-08-20

    A ''new'' process for developing control systems - Less engine testing - More robust control system - Shorter development cycle time - ''Smarter'' approach to engine control - On-board models describe engine behavior - Shorter, systematic calibration process - Customer and legislative requirements designed-in.

  13. New advances for modelling the debris avalanches

    NASA Astrophysics Data System (ADS)

    Cuomo, Sabatino; Cascini, Leonardo; Pastor, Manuel; Castorino, Giuseppe Claudio

    2013-04-01

    Flow-like landslides are a major global hazard and they occur worldwide causing a large number of casualties, significant structural damages to property and infrastructures as well as economic losses. When involving open slopes, these landslides often occur in triangular source areas where initial slides turn into avalanches through further failures and/or eventual soil entrainment. This paper deals with the numerical modelling of the propagation stage of debris avalanches which provides information such as the propagation pattern of the mobilized material, its velocity, thickness and run-out distance. In the paper, a "depth integrated" model is used which allows: i) adequately taking into account the irregular topography of real slopes which greatly affect the propagation stage and ii) using a less time consuming model than fully 3D approaches. The used model is named "GeoFlow_SPH" and it was formerly applied to theoretical, experimental and real case histories (Pastor et al., 2009; Cascini et al., 2012). In this work the behavior of debris avalanches is analyzed with special emphasis on the apical angle, one of the main features of this type of landslide, in relation to soil rheology, hillslope geometry and features of triggering area. Furthermore, the role of erosion has been investigated with reference to the uppermost parts of open slopes with a different steepness. These analyses are firstly carried out for simplified benchmark slopes, using both water-like materials (with no shear strength) and debris type materials. Then, three important case studies of Campania region (Cervinara, Nocera Inferiore e Sarno) are analyzed where debris avalanches involved pyroclastic soils originated from the eruptive products of Vesusius volcano. The results achieved for both benchmark slopes and real case histories outline the key role played by the erosion on the whole propagation stage of debris avalanches. The results are particularly satisfactory since they indicate the "GeoFlow_SPH" model as a suitable tool for the analysis of these phenomena. References Pastor, M., Haddad, B., Sorbino, G., Cuomo, S., Drempetic V. (2009). A depth-integrated, coupled SPH model for flow-like landslides and related phenomena. International Journal for Numerical and Analytical Methods in Geomechanics, 33, 143-184. Cascini L., Cuomo S., Pastor M., Sorbino G., Piciullo L. (2012). Modeling of propagation and entrainment phenomena for landslides of the flow type: the May 1998 case study. Proc. of 11th Int. Symposium on Landslides: Landslides and Engineered Slopes, Banf, Canada June 3-8, 2012, Ed. E. Eberhardt, C. Froese, K. Turner, S. Leroueil, ISBN 978-0-415-62423-6, 1723-1729.

  14. Plasma disruption modeling and simulation

    SciTech Connect

    Hassanein, A. [Argonne National Lab., IL (United States)

    1994-11-01

    Disruptions in tokamak reactors are considered a limiting factor to successful operation and reliable design. The behavior of plasma-facing components during a disruption is critical to the overall integrity of the reactor. Erosion of plasma facing-material (PFM) surfaces due to thermal energy dump during the disruption can severely limit the lifetime of these components and thus diminish the economic feasibility of the reactor. A comprehensive understanding of the interplay of various physical processes during a disruption is essential for determining component lifetime and potentially improving the performance of such components. There are three principal stages in modeling the behavior of PFM during a disruption. Initially, the incident plasma particles will deposit their energy directly on the PFM surface, heating it to a very high temperature where ablation occurs. Models for plasma-material interactions have been developed and used to predict material thermal evolution during the disruption. Within a few microseconds after the start of the disruption, enough material is vaporized to intercept most of the incoming plasma particles. Models for plasma-vapor interactions are necessary to predict vapor cloud expansion and hydrodynamics. Continuous heating of the vapor cloud above the material surface by the incident plasma particles will excite, ionize, and cause vapor atoms to emit thermal radiation. Accurate models for radiation transport in the vapor are essential for calculating the net radiated flux to the material surface which determines the final erosion thickness and consequently component lifetime. A comprehensive model that takes into account various stages of plasma-material interaction has been developed and used to predict erosion rates during reactor disruption, as well during induced disruption in laboratory experiments.

  15. Equivalent drawbead models for sheet forming simulation

    Microsoft Academic Search

    S. J. Moon; M. G. Lee; S. H. Lee; Y. T. Keum

    2010-01-01

    Equivalent drawbead models associated with drawbead types, with which the geometrical modeling of drawbeads can be replaced\\u000a in a numerical simulation of the stamping process, are introduced. The accuracy of the equivalent drawbead models rapidly\\u000a computing the drawbead restraining and opening forces, based on the hybrid membrane\\/bending method accommodating Barlat’s\\u000a anisotropic yield function for the plane stress state and the

  16. Blast furnace on-line simulation model

    Microsoft Academic Search

    Henrik Saxén

    1990-01-01

    A mathematical model of the ironmaking blast furnace (BF) is presented. The model describes the steady-state operation of\\u000a the furnace in one spatial dimension using real process data sampled at the steelworks. The measurement data are reconciled\\u000a by an interface routine which yields boundary conditions obeying the conservation laws of atoms and energy. The simulation\\u000a model, which provides a picture

  17. EPANET - AN ADVANCED WATER QUALITY MODELING PACKAGE FOR DISTRIBUTION SYSTEMS

    EPA Science Inventory

    EPANET is a third generation software package for modeling water quality within drinking water distribution systems. he program performs extended period simulation of hydraulic and water quality conditions within pressurized pipe networks. n addition to substance concentration wa...

  18. Cogeneration computer model assessment: Advanced cogeneration research study

    NASA Technical Reports Server (NTRS)

    Rosenberg, L.

    1983-01-01

    Cogeneration computer simulation models to recommend the most desirable models or their components for use by the Southern California Edison Company (SCE) in evaluating potential cogeneration projects was assessed. Existing cogeneration modeling capabilities are described, preferred models are identified, and an approach to the development of a code which will best satisfy SCE requirements is recommended. Five models (CELCAP, COGEN 2, CPA, DEUS, and OASIS) are recommended for further consideration.

  19. Advanced Methodology for Simulation of Complex Flows Using Structured Grid Systems

    NASA Technical Reports Server (NTRS)

    Steinthorsson, Erlendur; Modiano, David

    1995-01-01

    Detailed simulations of viscous flows in complicated geometries pose a significant challenge to current capabilities of Computational Fluid Dynamics (CFD). To enable routine application of CFD to this class of problems, advanced methodologies are required that employ (a) automated grid generation, (b) adaptivity, (c) accurate discretizations and efficient solvers, and (d) advanced software techniques. Each of these ingredients contributes to increased accuracy, efficiency (in terms of human effort and computer time), and/or reliability of CFD software. In the long run, methodologies employing structured grid systems will remain a viable choice for routine simulation of flows in complex geometries only if genuinely automatic grid generation techniques for structured grids can be developed and if adaptivity is employed more routinely. More research in both these areas is urgently needed.

  20. Development and integration of the Army's Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) HWIL facilities

    NASA Astrophysics Data System (ADS)

    LeSueur, Kenneth G.; Lowry, William; Morris, Joe

    2006-05-01

    The Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) is a suite of state-of-the-art hardware-in-the-loop (HWIL) simulation / test capabilities designed to meet the life-cycle testing needs of multi-spectral systems. This paper presents the major AMSTAR facility design concepts and each of the Millimeter Wave (MMW), Infrared (IR), and Semi-Active Laser (SAL) in-band scene generation and projection system designs. The emergence of Multispectral sensors in missile systems necessitates capabilities such as AMSTAR to simultaneous project MMW, IR, and SAL wave bands into a common sensor aperture.

  1. Development and integration of the Army's advanced multispectral simulation test acceptance resource (AMSTAR) HWIL facilities

    NASA Astrophysics Data System (ADS)

    LeSueur, Kenneth G.; Lowry, William; Morris, Joe

    2005-05-01

    The Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) is a suite of state-of-the-art Hardware-In-the-Loop (HWIL) simulation / test capabilities designed to meet the life-cycle testing needs of multi-spectral systems. This paper presents the major AMSTAR facility design concepts and each of the Millimeter Wave (MMW), Infrared (IR), and Semi-Active Laser (SAL) in-band scene generation and projection system designs. The emergence of Multispectral sensors in missile systems necessitates capabilities such as AMSTAR to simultaneous project MMW, IR, and SAL wave bands into a common sensor aperture.

  2. Advanced air revitalization system modeling and testing

    NASA Technical Reports Server (NTRS)

    Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

    1990-01-01

    To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

  3. Common modeling system for digital simulation

    NASA Technical Reports Server (NTRS)

    Painter, Rick

    1994-01-01

    The Joint Modeling and Simulation System is a tri-service investigation into a common modeling framework for the development digital models. The basis for the success of this framework is an X-window-based, open systems architecture, object-based/oriented methodology, standard interface approach to digital model construction, configuration, execution, and post processing. For years Department of Defense (DOD) agencies have produced various weapon systems/technologies and typically digital representations of the systems/technologies. These digital representations (models) have also been developed for other reasons such as studies and analysis, Cost Effectiveness Analysis (COEA) tradeoffs, etc. Unfortunately, there have been no Modeling and Simulation (M&S) standards, guidelines, or efforts towards commonality in DOD M&S. The typical scenario is an organization hires a contractor to build hardware and in doing so an digital model may be constructed. Until recently, this model was not even obtained by the organization. Even if it was procured, it was on a unique platform, in a unique language, with unique interfaces, and, with the result being UNIQUE maintenance required. Additionally, the constructors of the model expended more effort in writing the 'infrastructure' of the model/simulation (e.g. user interface, database/database management system, data journalizing/archiving, graphical presentations, environment characteristics, other components in the simulation, etc.) than in producing the model of the desired system. Other side effects include: duplication of efforts; varying assumptions; lack of credibility/validation; and decentralization in policy and execution. J-MASS provides the infrastructure, standards, toolset, and architecture to permit M&S developers and analysts to concentrate on the their area of interest.

  4. Advanced three-dimensional two-phase flow simulation tools for application to reactor safety (ASTAR)

    Microsoft Academic Search

    H. Staedtke; G. Franchello; B. Worth; U. Graf; P. Romstedt; A. Kumbaro; J. García-Cascales; H. Paillère; H. Deconinck; M. Ricchiuto; B. Smith; F. De Cachard; E. F. Toro; E. Romenski; S. Mimouni

    2005-01-01

    This paper summarizes the cumulative work undertaken in the frame of the EU shared-cost action “ASTAR Project”—the current status and future perspectives in the field of advanced numerical simulation of three-dimensional two-phase flow processes. This 3-year running project, which started in September 2000, involves seven partner institutes from around Europe. Specific emphasis is given to the further development of characteristic-based

  5. Advances in 3D Numerical Simulation of Viscous and Viscoelastic Mixing Flows

    Microsoft Academic Search

    Kiran V. Vyakaranam; Jozef L. Kokini

    \\u000a Mixing of highly viscous and viscoelastic fluids like wheat flour dough, pastes, batters, and syrups is often encountered\\u000a in the food industry. Study of the design of mixing equipment is aimed at achieving optimal mixing of the material, providing\\u000a guidelines for scale-up and comparison of batch and continuous process equipment. Recent advances in numerical simulation\\u000a techniques and availability of commercial

  6. Advanced deposition model for thermal activated chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface reactions on the substrate surface, conductive, convective, inductive and radiative heat transfer, species transport and thereto-elastic stress distributions. Gas phase and surface reactions are studied thermodynamically and kinetically. Based on experimental results, detailed reaction mechanisms are proposed and the deposition rates are predicted. The deposition model proposed could be used for other experiments with similar operating conditions. Four different growth systems are presented in this thesis to discuss comprehensive transport phenomena in crystal growth from vapor. The first is the polysilicon bulk growth by modified Siemens technique in which a silicon tube is used as the starting material. The research effort has been focused on system design, geometric and operating parameters optimization, and heterogeneous and homogeneous silane pyrolysis analysis. The second is the GaN thin film growth by iodine vapor phase epitaxy technique. Heat and mass transport is studied analytically and numerically. Gas phase and surface reactions are analyzed thermodynamically and kinetically. Quasi-equilibrium and kinetic deposition models are developed to predict the growth rate. The third one is the AlN thin film growth by halide vapor phase epitaxy technique. The effects of gas phase and surface reactions on the crystal growth rate and deposition uniformity are studied. The last one is the AlN sublimation growth system. The research effort has been focused on the effect of thermal environment evolution on the crystal growth process. The thermoelastic stress formed in the as-grown AlN crystal is also calculated.

  7. Simulation analysis: applications of discrete event simulation modeling to military problems

    Microsoft Academic Search

    Raymond R. Hill; John O. Miller; Gregory A. McIntyre

    2001-01-01

    The military is a big user of discrete event simulation models. The use of these models range from training and wargaming their constructive use in important military analyses. In this paper we discuss the uses of military simulation, the issues associated with military simulation to include categorizations of various types of military simulation. We then discuss three particular simulation studies

  8. Modeling surgical skill learning with cognitive simulation.

    PubMed

    Park, Shi-Hyun; Suh, Irene H; Chien, Jung-hung; Paik, Jaehyon; Ritter, Frank E; Oleynikov, Dmitry; Siu, Ka-Chun

    2011-01-01

    We used a cognitive architecture (ACT-R) to explore the procedural learning of surgical tasks and then to understand the process of perceptual motor learning and skill decay in surgical skill performance. The ACT-R cognitive model simulates declarative memory processes during motor learning. In this ongoing study, four surgical tasks (bimanual carrying, peg transfer, needle passing, and suture tying) were performed using the da Vinci© surgical system. Preliminary results revealed that an ACT-R model produced similar learning effects. Cognitive simulation can be used to demonstrate and optimize the perceptual motor learning and skill decay in surgical skill training. PMID:21335834

  9. Simulated annealing for generalized Skyrme models

    NASA Astrophysics Data System (ADS)

    Longpré, J.-P.; Marleau, L.

    2005-05-01

    We use a simulated annealing algorithm to find the static field configuration with the lowest energy in a given sector of topological charge for generalized SU(2) Skyrme models. These numerical results suggest that the following conjecture may hold: the symmetries of the soliton solutions of extended Skyrme models are the same as for the Skyrme model. Indeed, this is verified for two effective Lagrangians with terms of order six and order eight in derivatives of the pion fields, respectively, for topological charges B=1 up to B=4. We also evaluate the energy of these multiskyrmions using the rational maps ansatz. A comparison with the exact numerical results shows that the reliability of this approximation for extended Skyrme models is almost as good as for the pure Skyrme model. Some details regarding the implementation of the simulated annealing algorithm in one and three spatial dimensions are provided.

  10. WRF4G project: Advances in running climate simulations on the EGI Infrastructure

    NASA Astrophysics Data System (ADS)

    Blanco, Carlos; Cofino, Antonio S.; Fernández Quiruelas, Valvanuz; García, Markel; Fernández, Jesús

    2014-05-01

    The Weather Research and Forecasting For Grid (WRF4G) project is a two-year Spanish National R&D project, which has started in 2011. It is now a well established project, involving scientists and technical staff from several institutions, which contribute results to international initiatives such as CORDEX and European FP7 projects such as SPECS and EUPORIAS. The aim of the WRF4G project is to homogenize access hybrid Distributed Computer Infrastructures (DCIs), such as HPC and Grid infrastructures, for climate researchers. Additionally, it provides a productive interface to accomplish ambitious climate experiments such as regional hind-cast/forecast and sensitivity studies. Although Grid infrastructures are very powerful, they have some drawbacks for executing climate applications such as the WRF model. This makes necessary to encapsulate the applications in a middleware in order to provide the appropriate services for monitoring and management. Therefore, the challenge of the WRF4G project is to develop a generic adaptation framework (WRF4G framework) to disseminate it to the scientific community. The framework aims at simplifying the model access by releasing climate scientists from technical and computational aspects. In this contribution, we present some new advances of the WRF4G framework, including new components for designing experiments, simulation monitoring and data management. Additionally, we will show how WRF4G makes possible to run complex experiments on EGI infrastructures concurrently over several VOs such as esr and earth.vo.ibergrid. http://www.meteo.unican.es/software/wrf4g This work has been partially funded by the European Regional Development Fund (ERDF) and the Spanish National R&D Plan 2008-2011 (CGL2011-28864, WRF4G)

  11. Recent advances in Phase-Field Crystal modeling of

    E-print Network

    Chen, Long-Qing

    nucleation 33 #12;II. The Phase-Field Crystal Approach: a Simple Dynamical Density Functional Theory (K. RRecent advances in Phase-Field Crystal modeling of heterogeneous crystal nucleation a. Elder et al., PRL, 2002) II. The Phase-Field Crystal Approach: a Simple Dynamical Density Functional

  12. Upgrading and expanding capabilities in the advanced IRCM assessment model

    Microsoft Academic Search

    Alan D. Kerrick; David P. Forrai; Steven S. Samadi; James Maier

    1998-01-01

    The Air Force Research Laboratory develops the Advanced IR Countermeasures Assessment Model (AIAM), an in-house analysis tool for the National Air Intelligence Center (NAIC). AIAM allows NAIC analysts to predict the most effective countermeasure response by a foreign aircraft when engaged by IR missiles. This paper discusses enhancements to AIAM. These enhancements include the addition of IRCM decoys with lift

  13. Analysis of Intelligent Transportation Systems Using Model-Driven Simulations.

    PubMed

    Fernández-Isabel, Alberto; Fuentes-Fernández, Rubén

    2015-01-01

    Intelligent Transportation Systems (ITSs) integrate information, sensor, control, and communication technologies to provide transport related services. Their users range from everyday commuters to policy makers and urban planners. Given the complexity of these systems and their environment, their study in real settings is frequently unfeasible. Simulations help to address this problem, but present their own issues: there can be unintended mistakes in the transition from models to code; their platforms frequently bias modeling; and it is difficult to compare works that use different models and tools. In order to overcome these problems, this paper proposes a framework for a model-driven development of these simulations. It is based on a specific modeling language that supports the integrated specification of the multiple facets of an ITS: people, their vehicles, and the external environment; and a network of sensors and actuators conveniently arranged and distributed that operates over them. The framework works with a model editor to generate specifications compliant with that language, and a code generator to produce code from them using platform specifications. There are also guidelines to help researchers in the application of this infrastructure. A case study on advanced management of traffic lights with cameras illustrates its use. PMID:26083232

  14. Analysis of Intelligent Transportation Systems Using Model-Driven Simulations

    PubMed Central

    Fernández-Isabel, Alberto; Fuentes-Fernández, Rubén

    2015-01-01

    Intelligent Transportation Systems (ITSs) integrate information, sensor, control, and communication technologies to provide transport related services. Their users range from everyday commuters to policy makers and urban planners. Given the complexity of these systems and their environment, their study in real settings is frequently unfeasible. Simulations help to address this problem, but present their own issues: there can be unintended mistakes in the transition from models to code; their platforms frequently bias modeling; and it is difficult to compare works that use different models and tools. In order to overcome these problems, this paper proposes a framework for a model-driven development of these simulations. It is based on a specific modeling language that supports the integrated specification of the multiple facets of an ITS: people, their vehicles, and the external environment; and a network of sensors and actuators conveniently arranged and distributed that operates over them. The framework works with a model editor to generate specifications compliant with that language, and a code generator to produce code from them using platform specifications. There are also guidelines to help researchers in the application of this infrastructure. A case study on advanced management of traffic lights with cameras illustrates its use. PMID:26083232

  15. Advanced simulation for analysis of critical infrastructure : abstract cascades, the electric power grid, and Fedwire.

    SciTech Connect

    Glass, Robert John, Jr.; Stamber, Kevin Louis; Beyeler, Walter Eugene

    2004-08-01

    Critical Infrastructures are formed by a large number of components that interact within complex networks. As a rule, infrastructures contain strong feedbacks either explicitly through the action of hardware/software control, or implicitly through the action/reaction of people. Individual infrastructures influence others and grow, adapt, and thus evolve in response to their multifaceted physical, economic, cultural, and political environments. Simply put, critical infrastructures are complex adaptive systems. In the Advanced Modeling and Techniques Investigations (AMTI) subgroup of the National Infrastructure Simulation and Analysis Center (NISAC), we are studying infrastructures as complex adaptive systems. In one of AMTI's efforts, we are focusing on cascading failure as can occur with devastating results within and between infrastructures. Over the past year we have synthesized and extended the large variety of abstract cascade models developed in the field of complexity science and have started to apply them to specific infrastructures that might experience cascading failure. In this report we introduce our comprehensive model, Polynet, which simulates cascading failure over a wide range of network topologies, interaction rules, and adaptive responses as well as multiple interacting and growing networks. We first demonstrate Polynet for the classical Bac, Tang, and Wiesenfeld or BTW sand-pile in several network topologies. We then apply Polynet to two very different critical infrastructures: the high voltage electric power transmission system which relays electricity from generators to groups of distribution-level consumers, and Fedwire which is a Federal Reserve service for sending large-value payments between banks and other large financial institutions. For these two applications, we tailor interaction rules to represent appropriate unit behavior and consider the influence of random transactions within two stylized networks: a regular homogeneous array and a heterogeneous scale-free (fractal) network. For the stylized electric power grid, our initial simulations demonstrate that the addition of geographically unrestricted random transactions can eventually push a grid to cascading failure, thus supporting the hypothesis that actions of unrestrained power markets (without proper security coordination on market actions) can undermine large scale system stability. We also find that network topology greatly influences system robustness. Homogeneous networks that are 'fish-net' like can withstand many more transaction perturbations before cascading than can scale-free networks. Interestingly, when the homogeneous network finally cascades, it tends to fail in its entirety, while the scale-free tends to compartmentalize failure and thus leads to smaller, more restricted outages. In the case of stylized Fedwire, initial simulations show that as banks adaptively set their individual reserves in response to random transactions, the ratio of the total volume of transactions to individual reserves, or 'turnover ratio', increases with increasing volume. The removal of a bank from interaction within the network then creates a cascade, its speed of propagation increasing as the turnover ratio increases. We also find that propagation is accelerated by patterned transactions (as expected to occur within real markets) and in scale-free networks, by the 'attack' of the most highly connected bank. These results suggest that the time scale for intervention by the Federal Reserve to divert a cascade in Fedwire may be quite short. Ongoing work in our cascade analysis effort is building on both these specific stylized applications to enhance their fidelity as well as embracing new applications. We are implementing markets and additional network interactions (e.g., social, telecommunication, information gathering, and control) that can impose structured drives (perturbations) comparable to those seen in real systems. Understanding the interaction of multiple networks, their interdependencies, and in particular, the underlying mechanisms f

  16. Lifetime prediction modeling of airfoils for advanced power generation

    NASA Astrophysics Data System (ADS)

    Karaivanov, Ventzislav Gueorguiev

    The use of gases produced from coal as a turbine fuel offers an attractive means for efficiently generating electric power from our Nation's most abundant fossil fuel resource. The oxy-fuel and hydrogen-fired turbine concepts promise increased efficiency and low emissions on the expense of increased turbine inlet temperature (TIT) and different working fluid. Developing the turbine technology and materials is critical to the creation of these near-zero emission power generation technologies. A computational methodology, based on three-dimensional finite element analysis (FEA) and damage mechanics is presented for predicting the evolution of creep and fatigue in airfoils. We took a first look at airfoil thermal distributions in these advanced turbine systems based on CFD analysis. The damage mechanics-based creep and fatigue models were implemented as user modified routine in commercial package ANSYS. This routine was used to visualize the creep and fatigue damage evolution over airfoils for hydrogen-fired and oxy-fuel turbines concepts, and regions most susceptible to failure were indentified. Model allows for interaction between creep and fatigue damage thus damage due to fatigue and creep processes acting separately in one cycle will affect both the fatigue and creep damage rates in the next cycle. Simulation results were presented for various thermal conductivity of the top coat. Surface maps were created on the airfoil showing the development of the TGO scale and the Al depletion of the bond coat. In conjunction with model development, laboratory-scale experimental validation was executed to evaluate the influence of operational compressive stress levels on the performance of the TBC system. TBC coated single crystal coupons were exposed isothermally in air at 900, 1000, 1100oC with and without compressive load. Exposed samples were cross-sectioned and evaluated with scanning electron microscope (SEM). Performance data was collected based on image analysis. Energy-dispersive x-ray (EDX) was employed to study the elemental distribution in TBC system after exposure. Nanoindentation was used to study the mechanical properties (Young's modulus and hardness) of the components in the TBC system and their evolution with temperature and time.

  17. Experimental Noise Injection in Simulated Model Signals

    NASA Astrophysics Data System (ADS)

    Khan, Tariq; Udpa, Lalita; Udpa, Satish

    2011-06-01

    Nondestructive testing methods have been routinely, designed, evaluated and optimized using simulation models developed using various computational techniques. The simulated signal using computational model differs from the true signal in that the signal does not simulated experimental noise. In order to use the computational models more effectively for signal processing algorithm development, experimental noise should be injected in the simulated signals. Experimental noise PDF (probability density function) can be numerically calculated from measured noise. The experimental signal PDF can then be generated by combining the simulation signal and measurement noise PDF. Sampling from experimental signal distribution is not a straight forward task as the distribution is generally not a standard parametric distribution. This paper presents a method that approximates experimental signal PDF as a mixture of Gaussian densities. Maximum-likelihood estimate of the parameters of Gaussian distributions from a given data set are computed using expectation-maximization (EM) technique. A sampling scheme from the mixture of Gaussian densities is also discussed. The overall algorithm is implemented on eddy current inspection data from steam generator (SG) tubing.

  18. A survey of recent advances in discrete input parameter discrete-event simulation optimization

    Microsoft Academic Search

    JAMES R. SWISHER; PAUL D. HYDEN; SHELDON H. JACOBSON; LEE W. SCHRUBEN

    2004-01-01

    Discrete-event simulation optimization is a problem of significant interest to practitioners interested in extracting useful information about an actual (or yet to be designed) system that can be modeled using discrete-event simulation. This paper presents a survey of the literature on discrete-event simulation optimization published in recent years (1988 to the present), with a particular focus on discrete input parameter

  19. Learning Causal Models via Progressive Alignment & Qualitative Modeling: A Simulation

    Microsoft Academic Search

    Scott E. Friedman; Kenneth D. Forbus

    Learning causal models is one of the central problems of cognitive science. We describe a simulation of early learning in physical domains from observations that uses progressive alignment and qualitative modeling to derive plausible causal models from observations. We show how protohistories can be created via progressive alignment and used with covariance algorithms to infer causality. The result, a causal

  20. Computational studies of horizontal axis wind turbines in high wind speed condition using advanced turbulence models

    NASA Astrophysics Data System (ADS)

    Benjanirat, Sarun

    Next generation horizontal-axis wind turbines (HAWTs) will operate at very high wind speeds. Existing engineering approaches for modeling the flow phenomena are based on blade element theory, and cannot adequately account for 3-D separated, unsteady flow effects. Therefore, researchers around the world are beginning to model these flows using first principles-based computational fluid dynamics (CFD) approaches. In this study, an existing first principles-based Navier-Stokes approach is being enhanced to model HAWTs at high wind speeds. The enhancements include improved grid topology, implicit time-marching algorithms, and advanced turbulence models. The advanced turbulence models include the Spalart-Allmaras one-equation model, k-epsilon, k-o and Shear Stress Transport (k-o-SST) models. These models are also integrated with detached eddy simulation (DES) models. Results are presented for a range of wind speeds, for a configuration termed National Renewable Energy Laboratory Phase VI rotor, tested at NASA Ames Research Center. Grid sensitivity studies are also presented. Additionally, effects of existing transition models on the predictions are assessed. Data presented include power/torque production, radial distribution of normal and tangential pressure forces, root bending moments, and surface pressure fields. Good agreement was obtained between the predictions and experiments for most of the conditions, particularly with the Spalart-Allmaras-DES model.

  1. Applications of discrete event simulation modeling to military problems

    Microsoft Academic Search

    Raymond R. Hill; J. O. Miller; Gregory A. McIntyre

    2001-01-01

    The military is a big user of discrete event simulation models. The use of these models range from training and wargaming their constructive use in important military analyses. In this paper we discuss the uses of military simulation, the issues associated with military simulation to include categorizations of various types of military simulation. We then discuss three particular simulation studies

  2. Gnie mcanique Thermal Modelling And Correlation of a Comet Simulation

    E-print Network

    Candea, George

    of future investigations on comet CG by the ESA Rosetta mission. A thermal model of the simulation chamberSECTION DE Génie mécanique Thermal Modelling And Correlation of a Comet Simulation Facility Author Thomas Beck André Bieler Why simulating comets? The comet simulation facility SCITEAS (Simulation Chamber

  3. Test model designs for advanced refractory ceramic materials

    NASA Technical Reports Server (NTRS)

    Tran, Huy Kim

    1993-01-01

    The next generation of space vehicles will be subjected to severe aerothermal loads and will require an improved thermal protection system (TPS) and other advanced vehicle components. In order to ensure the satisfactory performance system (TPS) and other advanced vehicle materials and components, testing is to be performed in environments similar to space flight. The design and fabrication of the test models should be fairly simple but still accomplish test objectives. In the Advanced Refractory Ceramic Materials test series, the models and model holders will need to withstand the required heat fluxes of 340 to 817 W/sq cm or surface temperatures in the range of 2700 K to 3000 K. The model holders should provide one dimensional (1-D) heat transfer to the samples and the appropriate flow field without compromising the primary test objectives. The optical properties such as the effective emissivity, catalytic efficiency coefficients, thermal properties, and mass loss measurements are also taken into consideration in the design process. Therefore, it is the intent of this paper to demonstrate the design schemes for different models and model holders that would accommodate these test requirements and ensure the safe operation in a typical arc jet facility.

  4. ADAPTATION OF THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL TO THE EPA VAX COMPUTER - MODIFICATIONS AND TESTING

    EPA Science Inventory

    The Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model simulates long-term transport and deposition of oxides of and nitrogen. t is a potential screening tool for assessing long-term effects on regional visibility from sulfur emission sources. owever, a rigorou...

  5. Evaluation of reliability modeling tools for advanced fault tolerant systems

    NASA Technical Reports Server (NTRS)

    Baker, Robert; Scheper, Charlotte

    1986-01-01

    The Computer Aided Reliability Estimation (CARE III) and Automated Reliability Interactice Estimation System (ARIES 82) reliability tools for application to advanced fault tolerance aerospace systems were evaluated. To determine reliability modeling requirements, the evaluation focused on the Draper Laboratories' Advanced Information Processing System (AIPS) architecture as an example architecture for fault tolerance aerospace systems. Advantages and limitations were identified for each reliability evaluation tool. The CARE III program was designed primarily for analyzing ultrareliable flight control systems. The ARIES 82 program's primary use was to support university research and teaching. Both CARE III and ARIES 82 were not suited for determining the reliability of complex nodal networks of the type used to interconnect processing sites in the AIPS architecture. It was concluded that ARIES was not suitable for modeling advanced fault tolerant systems. It was further concluded that subject to some limitations (the difficulty in modeling systems with unpowered spare modules, systems where equipment maintenance must be considered, systems where failure depends on the sequence in which faults occurred, and systems where multiple faults greater than a double near coincident faults must be considered), CARE III is best suited for evaluating the reliability of advanced tolerant systems for air transport.

  6. Simulation Modeling and Performance Evaluation of Space Networks

    NASA Technical Reports Server (NTRS)

    Jennings, Esther H.; Segui, John

    2006-01-01

    In space exploration missions, the coordinated use of spacecraft as communication relays increases the efficiency of the endeavors. To conduct trade-off studies of the performance and resource usage of different communication protocols and network designs, JPL designed a comprehensive extendable tool, the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE). The design and development of MACHETE began in 2000 and is constantly evolving. Currently, MACHETE contains Consultative Committee for Space Data Systems (CCSDS) protocol standards such as Proximity-1, Advanced Orbiting Systems (AOS), Packet Telemetry/Telecommand, Space Communications Protocol Specification (SCPS), and the CCSDS File Delivery Protocol (CFDP). MACHETE uses the Aerospace Corporation s Satellite Orbital Analysis Program (SOAP) to generate the orbital geometry information and contact opportunities. Matlab scripts provide the link characteristics. At the core of MACHETE is a discrete event simulator, QualNet. Delay Tolerant Networking (DTN) is an end-to-end architecture providing communication in and/or through highly stressed networking environments. Stressed networking environments include those with intermittent connectivity, large and/or variable delays, and high bit error rates. To provide its services, the DTN protocols reside at the application layer of the constituent internets, forming a store-and-forward overlay network. The key capabilities of the bundling protocols include custody-based reliability, ability to cope with intermittent connectivity, ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses. In this presentation, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the use of MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions

  7. WATER SUPPLY SIMULATION MODEL. VOLUME 3. DOCUMENTATION

    EPA Science Inventory

    This three-volume report describes the development of a water supply simulation model (WSSM), a system of computer programs that allows for a systematic evaluation of the physical and economic characteristics of a water distribution system in a spatial framework. The WSSM concept...

  8. TIRE MODELS IN AIRCRAFT LANDING GEAR SIMULATION

    Microsoft Academic Search

    M. T. P. van Slagmaat

    1992-01-01

    This report discusses the development of a simulation model of an aircraft landing gear describing its typical non-linear behaviour. The development of the design tool -which correlates the actual design parameters with the performance of the gear- is a part of the research project that investigates the estimation of the nonlinear dynamical system, which an aircraft landing gear is. This

  9. Modeling and Simulation for Flexible Ureteroscopy

    E-print Network

    Janardan, Ravi

    patient-specific calyceal anatomy, identifying stone size and location, and scope selection a combination of physical and virtual prototyping in 3D. Specifically, 3D-printing techniques are used to facilitate simulation studies and interaction with a virtual model. Conclusion The development of a patient

  10. Biological Invasion: Observations, Theory, Models, Simulations

    E-print Network

    Biological Invasion: Observations, Theory, Models, Simulations Sergei Petrovskii Department;Introduction: What it is all about The term biological invasion is a common name for a variety of phenomena invasionStages of biological invasion. (a) Introduction of an alien species: (b) Establishment

  11. Modelling and Simulation in Aerodynamic Design

    E-print Network

    Mosegaard, Klaus

    Modelling and Simulation in Aerodynamic Design In different kinds of aerodynamic design elements is too complex. Aerodynamic properties of different airfoils are found from either numerical turbine blade, two design features are important. The aerodynamic design attempts to optimize the blade

  12. Optoelectronic Device Modeling Using Field Simulation Techniques

    Microsoft Academic Search

    Minya Zhang

    1998-01-01

    Optoelectronic devices are important devices in optical fiber communications, optical signal processing, and optoelectronic equipment. This thesis develops new models for optoelectronic devices using electromagnetic field simulation techniques. To demonstrate this new technique, two kinds of optoelectronic devices are investigated in this thesis. Vertical cavity surface emitting laseer (VCSEL) is taken as the first research example due to the promising

  13. Optoelectronic device modeling using field simulation techniques

    Microsoft Academic Search

    Minya Zhang

    1998-01-01

    Optoelectronic devices are important devices in optical fiber communications, optical signal processing, and optoelectronic equipment. This thesis develops new models for optoelectronic devices using electromagnetic field simulation techniques. ^ To demonstrate this new technique, two kinds of optoelectronic devices are investigated in this thesis. Vertical cavity surface emitting laser (VCSEL) is taken as the first research example due to the

  14. Theory, Modeling and Simulation Annual Report 2000

    Microsoft Academic Search

    David A Dixon; Bruce C Garrett; TP Straatsma; Donald R Jones; Scott Studham; Robert J Harrison; Jeffrey A Nichols

    2001-01-01

    This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM and S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment

  15. Theory, Modeling and Simulation Annual Report 2000

    Microsoft Academic Search

    David A. Dixon; Bruce C. Garrett; Tp Straatsma; Donald R. Jones; Ronald S. Studham; Robert J. Harrison; Jeffrey A. Nichols

    2001-01-01

    This annual report describes the 2000 research accomplishments for the Theory, Modeling, and Simulation (TM&S) directorate, one of the six research organizations in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). EMSL is a U.S. Department of Energy (DOE) national scientific user facility and is the centerpiece of the DOE commitment to providing

  16. Love Kills:. Simulations in Penna Ageing Model

    NASA Astrophysics Data System (ADS)

    Stauffer, Dietrich; Cebrat, Stanis?aw; Penna, T. J. P.; Sousa, A. O.

    The standard Penna ageing model with sexual reproduction is enlarged by adding additional bit-strings for love: Marriage happens only if the male love strings are sufficiently different from the female ones. We simulate at what level of required difference the population dies out.

  17. VARIANCE REDUCTION IN SIMULATIONS OF LOSS MODELS

    E-print Network

    Srikant, Rayadurgam

    VARIANCE REDUCTION IN SIMULATIONS OF LOSS MODELS by Rayadurgam Srikant 1 and Ward Whitt 2 October). The variance reduction is often dramatic when the blocking probability is high and the service times are highly component estimators are very unequal, the variance reduction from the optimal convex combination is about 1

  18. VARIANCE REDUCTION IN SIMULATIONS OF LOSS MODELS

    Microsoft Academic Search

    Rayadurgam Srikant; Ward Whitt

    1995-01-01

    We propose a new estimator of steady-state blocking probabilities for simulations of stochasticloss models that can be much more e#cient than the natural estimator (ratio of losses to arrivals).The proposed estimator is a convex combination of the natural estimator and an indirect estimatorbased on the average number of customers in service, obtained from Little's law (L = #W ). Itexploits

  19. Modeling and Simulation Information Analysis Center

    NSDL National Science Digital Library

    The Modeling and Simulation Information Analysis Center (MSIAC) assists the Department of Defense (DoD) in meeting its M&S needs "by providing scientific, technical, and operational support information and services." Through the Help Desk, MSIAC also answers technical inquiries from non-DoD customers, who agree to pay for their service beyond the first two hours. The group has experience in weapons technology including WMD, information management, modeling and simulation, operations analysis, chemical and explosive sciences, material sciences, spectrum engineering, wireless communication, life sciences, medical informatics and telemedicine, transportation systems, and reliability, availability, and maintainability. A wealth of resources are available from this website, including the Modeling & Simulation Resource Repository (MSRR), which is described as "the first place to go for answers to M&S" and Glossary of Modeling and Simulation (M&S) Terms, information on special topics of interest within M&S, and links to related websites. The MSIAC's M&S Journal Online offers quarterly articles of interest to the M&S community free of charge. This site is also reviewed in the March 25, 2005_NSDL MET Report_.

  20. A simulation model for Dynamic File Management

    Microsoft Academic Search

    Lawrence L. Rose; Malcolm A. Gotterer; Jack C. Hayya

    1974-01-01

    This paper describes a FORTRAN simulation program written to carry out Dynamic File Management (DFM) strategies. The DFM model provides effective management of secondary storage while enhancing throughput time. The main problems we address are: how data is moved from level to level; the determination of criteria to justify file movement; and the implications of implementing the DFM techniques. It