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1

Advanced Space Shuttle simulation model  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

2

Advanced Space Shuttle simulation model  

NASA Technical Reports Server (NTRS)

The effects of atmospheric turbulence in horizontal and near-horizontal flight during the return of the Space Shuttle are important for determining design, control, and pilot-in-the-loop effects. A nonrecursive model (based on vonKarman spectra) for atmospheric turbulence along the flight path of the Shuttle Orbiter has been developed which provides for simulation of instantaneous vertical and horizontal gusts at the vehicle center-of-gravity and also for simulation of instantaneous gust gradients. Based on this model the time series for gusts and gust gradients have been generated and stored on a series of magnetic tapes which are 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, and conclusions and recommendations are presented. Appendices provide tabulated one-dimensional vonKarman spectra, a discussion of the minimum frequency simulated, and the results of spectral and statistical analyses of the SSTT.

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

1982-01-01

3

Center for Advanced Modeling and Simulation Intern  

SciTech Connect

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.

Gertman, Vanessa

2010-01-01

4

Center for Advanced Modeling and Simulation Intern  

ScienceCinema

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.

Gertman, Vanessa

2013-05-28

5

METC Gasifier Advanced Simulation (MGAS) model  

SciTech Connect

Morgantown Energy Technology Center is developing an advanced moving-bed gasifier, which is the centerpiece of the Integrated Gasifier Combined-Cycle (IGCC) system, with the features of good efficiency, low cost, and minimal environmental impact. A mathematical model of the gasifier, the METC-Gasifier Advanced Simulation (MGAS) model, has been developed for the analysis and design of advanced gasifiers and other moving-bed gasifiers. This report contains the technical and the user manuals of the MGAS model. The MGAS model can describe the transient operation of coflow, counterflow, or fixed-bed gasifiers. It is a one-dimensional model and can simulate the addition and withdrawal of gas and solids at multiple locations in the bed, a feature essential for simulating beds with recycle. The model describes the reactor in terms of a gas phase and a solids (coal or char) phase. These phases may exist at different temperatures. The model considers several combustion, gasification, and initial stage reactions. The model consists of a set of mass balances for 14 gas species and three coal (pseudo-) species and energy balances for the gas and the solids phases. The resulting partial differential equations are solved using a finite difference technique.

Syamlal, M. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States); Bissett, L.A. [USDOE Morgantown Energy Technology Center, WV (United States)

1992-01-01

6

Simulation of Advanced Transaction Models Using GOLOG  

Microsoft Academic Search

We propose a logical framework for describing, reasoning about, and simulating transaction mod- els that relax some of the ACID (Atomicity-Consistency-Isolation-Durability) properties of classi- cal transactions. Such extensions, usually called advanced transaction models (ATMs), have been proposed for dealing with new database applications involving long-lived, endless, and cooperative activities. Our approach appeals to non-Markovian theories, in which one may refer

Iluju Kiringa

2001-01-01

7

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

NASA Technical Reports Server (NTRS)

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.

Antonsson, Erik; Gombosi, Tamas

2005-01-01

8

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 ...

9

Modelling, Simulation, Testing, and Optimization of Advanced Hybrid Vehicle Powertrains  

E-print Network

Modelling, Simulation, Testing, and Optimization of Advanced Hybrid Vehicle Powertrains By Jeffrey in the Department of Mechanical Engineering ©Jeffrey Wishart, 2008 University of Victoria All rights reserved of the author. #12;ii Modelling, Simulation, Testing and Optimization of Advanced Hybrid Vehicle Powertrains

Victoria, University of

10

Advanced in turbulence physics and modeling by direct numerical simulations  

NASA Technical Reports Server (NTRS)

The advent of direct numerical simulations of turbulence has opened avenues for research on turbulence physics and turbulence modeling. Direct numerical simulation provides values for anything that the scientist or modeler would like to know about the flow. An overview of some recent advances in the physical understanding of turbulence and in turbulence modeling obtained through such simulations is presented.

Reynolds, W. C.

1987-01-01

11

MGAS. METC-Gasifier Advanced Simulation Model  

SciTech Connect

MGAS is a mechanistic model for describing the transient operation of coflow, counterflow, or fixed-bed gasifiers. The model describes the gasifier in one or two dimensions and can simulate the addition, withdrawal, or recycle of gas and solids at multiple locations in the bed.

Syamlal, M. [EG and G, W.A.S.C. Inc., Morgantown, WV (United States); Bissett, L.A. [USDOE Morgantown Energy Tech. Ctr., WV (United States)

1991-01-01

12

Gasification CFD Modeling for Advanced Power Plant Simulations  

SciTech Connect

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 NETL’s Advanced Process Engineering Co-Simulator for coupling high-fidelity equipment models with process simulation for the design, analysis, and optimization of advanced power plants. Using APECS, we have coupled the entrained-flow gasifier CFD model into a coal-fired, gasification-based FutureGen power and hydrogen production plant. The results for the FutureGen co-simulation illustrate how the APECS technology can help engineers better understand and optimize gasifier fluid dynamics and related phenomena that impact overall power plant performance.

Zitney, S.E.; Guenther, C.P.

2005-09-01

13

Advanced modeling and simulation to design and manufacture high performance and reliable advanced microelectronics and microsystems.  

SciTech Connect

An interdisciplinary team of scientists and engineers having broad expertise in materials processing and properties, materials characterization, and computational mechanics was assembled to develop science-based modeling/simulation technology to design and reproducibly manufacture high performance and reliable, complex microelectronics and microsystems. The team's efforts focused on defining and developing a science-based infrastructure to enable predictive compaction, sintering, stress, and thermomechanical modeling in ''real systems'', including: (1) developing techniques to and determining materials properties and constitutive behavior required for modeling; (2) developing new, improved/updated models and modeling capabilities, (3) ensuring that models are representative of the physical phenomena being simulated; and (4) assessing existing modeling capabilities to identify advances necessary to facilitate the practical application of Sandia's predictive modeling technology.

Nettleship, Ian (University of Pittsburgh, Pittsburgh, PA); Hinklin, Thomas; Holcomb, David Joseph; Tandon, Rajan; Arguello, Jose Guadalupe, Jr. (,; .); Dempsey, James Franklin; Ewsuk, Kevin Gregory; Neilsen, Michael K.; Lanagan, Michael (Pennsylvania State University, University Park, PA)

2007-07-01

14

An advanced modelling tool for simulating complex river systems  

Microsoft Academic Search

The present paper describes MOHID River Network (MRN), a 1D hydrodynamic model for river networks as part of MOHID Water Modelling System, which is a modular system for the simulation of water bodies (hydrodynamics and water constituents). MRN is capable of simulating water quality in the aquatic and benthic phase and its development was especially focused on the reproduction of

Ana Rosa Trancoso; Frank Braunschweig; Pedro Chambel Leitão; Matthias Obermann; Ramiro Neves

2009-01-01

15

Advanced 3D Photocathode Modeling and Simulations Final Report  

SciTech Connect

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.

Dimitre A Dimitrov; David L Bruhwiler

2005-06-06

16

An advancement in cyclic plasticity modeling for multiaxial ratcheting simulation  

Microsoft Academic Search

In a search for a constitutive model for ratcheting simulations, the models by Chaboche, Ohno–Wang, McDowell, Jiang–Sehitoglu, Voyiadjis–Basuroychowdhury and AbdelKarim–Ohno are evaluated against a set of uniaxial and biaxial ratcheting responses. With the assumption of invariant shape of the yield surface during plastic loading, the ratcheting simulations for uniaxial loading are primarily a function of the plastic modulus calculation, whereas

Shafiqul Bari; Tasnim Hassan

2002-01-01

17

Simulation of Hurricane Isabel Using the Advanced Circulation Model (ADCIRC)  

Microsoft Academic Search

Hurricane Isabel made landfall near Drum Inlet, about 240 km south of the Chesapeake Bay mouth, on the Outer Banks of North Carolina at 1700 UTC (GMT 12:00), September 18, 2003. Hurricane Isabel is considered to be one of the most significant tropical cyclones to affect portions of northeastern North Carolina and east- central Virginia. The ADvanced CIRCulation Model (ADCIRC)

Jian Shen; Wenping Gong; Harry Wang

18

Numerical simulation of turbomachinery flows with advanced turbulence models  

NASA Astrophysics Data System (ADS)

A three dimensional full Navier-Stokes (FNS) code is used to simulate complex turbomachinery flows. The code incorporates an explicit multistep scheme and solves a conservative form of the density averaged continuity, momentum, and energy equations. A compressible low Reynolds number form of the k-epsilon turbulence model, and a q-omega model and an algebraic Reynolds stress model have been incorporated in a fully coupled manner to approximate Reynolds stresses. The code is used to predict the viscous flow field in a backswept transonic centrifugal compressor for which laser two focus data is available. The code is also used to simulate the tip clearance flow in a cascade. The code has been extended to include unsteady Euler solutions for predicting the unsteady flow through a cascade due to incoming wakes, simulating rotor-stator interactions.

Lakshminarayana, B.; Kunz, R.; Luo, J.; Fan, S.

1992-07-01

19

Advanced modelling of failure mechanisms in aluminium sheet forming simulation  

Microsoft Academic Search

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

Holger Aretz; Stefan Keller; Rolf Vogt; Olaf Engler

2009-01-01

20

An advanced modelling tool for simulating complex river systems.  

PubMed

The present paper describes MOHID River Network (MRN), a 1D hydrodynamic model for river networks as part of MOHID Water Modelling System, which is a modular system for the simulation of water bodies (hydrodynamics and water constituents). MRN is capable of simulating water quality in the aquatic and benthic phase and its development was especially focused on the reproduction of processes occurring in temporary river networks (flush events, pools formation, and transmission losses). Further, unlike many other models, it allows the quantification of settled materials at the channel bed also over periods when the river falls dry. These features are very important to secure mass conservation in highly varying flows of temporary rivers. The water quality models existing in MOHID are base on well-known ecological models, such as WASP and ERSEM, the latter allowing explicit parameterization of C, N, P, Si, and O cycles. MRN can be coupled to the basin model, MOHID Land, with computes runoff and porous media transport, allowing for the dynamic exchange of water and materials between the river and surroundings, or it can be used as a standalone model, receiving discharges at any specified nodes (ASCII files of time series with arbitrary time step). These features account for spatial gradients in precipitation which can be significant in Mediterranean-like basins. An interface has been already developed for SWAT basin model. PMID:19215966

Trancoso, Ana Rosa; Braunschweig, Frank; Chambel Leitão, Pedro; Obermann, Matthias; Neves, Ramiro

2009-04-01

21

Real time digital harmonic modeling and simulation: an advanced tool for understanding power system harmonics mechanisms  

Microsoft Academic Search

Off-line computation and sometimes full transient time domain simulation has been the tool of choice for modeling power system harmonic phenomena in the past. Due to significant advances in real-time digital network simulation technologies, both in decreasing time step size and increased model complexity, this tool becomes more attractive for advanced harmonic analysis. This paper proposes the use of hardware-in-loop

M. Steurer; S. Woodruff

2004-01-01

22

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...

23

The role of advanced engineering simulation in model-based design  

SciTech Connect

The agile manufacturing paradigm engenders many new concepts and work approaches for manufacturing operations. A technology often invoked in the concept of agility is modeling and simulation. Few would disagree that modeling and simulation holds the potential to substantially reduce the product development cycle and lead to improve product reliability and performance. Advanced engineering simulation can impact manufacturing in three areas: process design, product design, and process control. However, despite that promise, the routine utilization of modeling and simulation by industry within the design process is very limited. Advanced simulation is still used primarily in a troubleshooting mode examining design or process problems after the fact. Sandia National Laboratories has been engaged in the development of advanced engineering simulation tools for many years and more recently has begun to focus on the application of such models to manufacturing processes important for the defense industry. These efforts involve considerable interaction and cooperative research with US industry. Based upon this experience, this presentation examines the elements that are necessary for advanced engineering simulation to become an integral part of the design process.

Hommert, P.J.; Biffle, J.H. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center

1995-03-01

24

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

Microsoft Academic Search

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

Kimberlyn C. Mousseau

2011-01-01

25

Development of a VOR/DME model for an advanced concepts simulator  

NASA Technical Reports Server (NTRS)

The report presents a definition of a VOR/DME, airborne and ground systems simulation model. This description was drafted in response to a need in the creation of an advanced concepts simulation in which flight station design for the 1980 era can be postulated and examined. The simulation model described herein provides a reasonable representation of VOR/DME station in the continental United States including area coverage by type and noise errors. The detail in which the model has been cast provides the interested researcher with a moderate fidelity level simulator tool for conducting research and evaluation of navigator algorithms. Assumptions made within the development are listed and place certain responsibilities (data bases, communication with other simulation modules, uniform round earth, etc.) upon the researcher.

Steinmetz, G. G.; Bowles, R. L.

1984-01-01

26

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

SciTech Connect

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.

Schultz, Peter Andrew

2011-12-01

27

Recent advances in semi-analytical scattering models for NDT simulation  

NASA Astrophysics Data System (ADS)

For several years, CEA-LIST and partners have been developing ultrasonic simulation tools with the aim of modelling non-destructive evaluation. The existing ultrasonic modules allow us to simulate fully real ultrasonic inspection scenarios in a range of applications which requires the computation of the propagated beam, as well as its interaction with flaws. To fulfil requirements of an intensive use (for parametric studies), the choice has been made to adopt mainly analytical approximate or exact methods to model the scattering of ultrasound by flaws. The applied analytical theories (Kirchhoff and Born approximations, GTD, SOV...) were already described in previous GDR communication. Over the years, this "semi-analytical" approach has been enriched by adaptations and improvements of the existing models or by new models, in order to extend the applicability of the simulation tools. This paper is devoted to the following recent advances performed in the framework of this approach: The SOV method based on the exact analytical model for the scattering from a cylindrical cavity has been extended in 3D to account for field variations along the cylinder. This new 3D model leads to an improvement in simulation of small side-drilled holes. Concerning the geometrical theories of diffraction (GTD), subroutines for calculation of the 2D wedge diffraction coefficients (for bulk or Rayleigh incident waves) have been developed by the Waves and Fields Group and uniform corrections (UAT and UTD) are under investigation. Modelling of the contribution of the head wave and creeping wave to the echoes arising from a wedge. Numerous experimental validations of the developed models are provided. New possibilities offered by these new developments are emphasized.

Darmon, M.; Chatillon, S.; Mahaut, S.; Calmon, P.; Fradkin, L. J.; Zernov, V.

2011-01-01

28

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

SciTech Connect

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.

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

2009-10-12

29

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

SciTech Connect

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.

Kimberlyn C. Mousseau

2011-10-01

30

Computational Advances in the Arctic Terrestrial Simulator: Modeling Permafrost Degradation in a Warming Arctic  

NASA Astrophysics Data System (ADS)

The terrestrial Arctic has been a net sink of carbon for thousands of years, but warming trends suggest this may change. As the terrestrial Arctic warms, degradation of the permafrost results in significant melting of the ice wedges that support low-centered polygonal ground. This leads to subsidence of the topography, inversion of the polygonal ground, and restructuring of drainage networks. The change in hydrology and vegetation that result from these processes is poorly understood. Predictive simulation of the fate of this carbon is critical for understanding feedback effects between the terrestrial Arctic and climate change. Simulation of this system at fine scales presents many challenges. Flow and energy equations are solved on both the surface and subsurface domains, and deformation of the soil subsurface must couple with both. Additional processes such as snow, evapo-transpiration, and biogeochemistry supplement this THMC model. While globally implicit coupling methods enable conservation of mass and energy on the combined domain, care must be taken to ensure conservation as the soil subsides and the mesh deforms. Uncertainty in both critical physics of each process model and in coupling to maintain accuracy between processes suggests the need for a versatile many-physics framework. This framework should allow swapping of both processes and constitutive relations, and enable easy numerical experimentation of coupling strategies. Deformation dictates the need for advanced discretizations which maintain accuracy and a mesh framework capable of calculating smooth deformation with remapped fields. And latent heat introduces strong nonlinearities, requiring robust solvers and an efficient globalization strategy. Here we discuss advances as implemented in the Arctic Terrestrial Simulator (ATS), a many-physics framework and collection of physics kernels based upon Amanzi. We demonstrate the deformation capability, conserving mass and energy while simulating soil subsidence due to bulk ice melting. Mimetic finite difference methods are used to maintain accuracy during mesh deformation. Globalization strategies similar to a local change of variables greatly extend the timestep size without requiring additional residual evaluations. Finally, ATS leverages tree structures for process kernels and data dependencies, enabling versatile combinations of processes and constitutive models and dynamic experimentation with coupling strategies. These advances are demonstrated in a series of problems coupling the thermal-mechanical-hydrological core of the ATS. This work was supported by LANL Laboratory Directed Research and Development Project LDRD201200068DR.

Coon, E.; Berndt, M.; Garimella, R.; Moulton, J. D.; Manzini, G.; Painter, S. L.

2013-12-01

31

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

Microsoft Academic Search

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

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

32

In-Service Design & Performance Prediction of Advanced Fusion Material Systems by Computational Modeling and Simulation  

SciTech Connect

This final report on "In-Service Design & Performance Prediction of Advanced Fusion Material Systems by Computational Modeling and Simulation" (DE-FG03-01ER54632) consists of a series of summaries of work that has been published, or presented at meetings, or both. It briefly describes results on the following topics: 1) A Transport and Fate Model for Helium and Helium Management; 2) Atomistic Studies of Point Defect Energetics, Dynamics and Interactions; 3) Multiscale Modeling of Fracture consisting of: 3a) A Micromechanical Model of the Master Curve (MC) Universal Fracture Toughness-Temperature Curve Relation, KJc(T - To), 3b) An Embrittlement DTo Prediction Model for the Irradiation Hardening Dominated Regime, 3c) Non-hardening Irradiation Assisted Thermal and Helium Embrittlement of 8Cr Tempered Martensitic Steels: Compilation and Analysis of Existing Data, 3d) A Model for the KJc(T) of a High Strength NFA MA957, 3e) Cracked Body Size and Geometry Effects of Measured and Effective Fracture Toughness-Model Based MC and To Evaluations of F82H and Eurofer 97, 3-f) Size and Geometry Effects on the Effective Toughness of Cracked Fusion Structures; 4) Modeling the Multiscale Mechanics of Flow Localization-Ductility Loss in Irradiation Damaged BCC Alloys; and 5) A Universal Relation Between Indentation Hardness and True Stress-Strain Constitutive Behavior. Further details can be found in the cited references or presentations that generally can be accessed on the internet, or provided upon request to the authors. Finally, it is noted that this effort was integrated with our base program in fusion materials, also funded by the DOE OFES.

G. R. Odette; G. E. Lucas

2005-11-15

33

The Nuclear Energy Advanced Modeling and Simulation Safeguards and Separations Reprocessing Plant Toolkit  

SciTech Connect

This report details the progress made in the development of the Reprocessing Plant Toolkit (RPTk) for the DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. RPTk is an ongoing development effort intended to provide users with an extensible, integrated, and scalable software framework for the modeling and simulation of spent nuclear fuel reprocessing plants by enabling the insertion and coupling of user-developed physicochemical modules of variable fidelity. The NEAMS Safeguards and Separations IPSC (SafeSeps) and the Enabling Computational Technologies (ECT) supporting program element have partnered to release an initial version of the RPTk with a focus on software usability and utility. RPTk implements a data flow architecture that is the source of the system's extensibility and scalability. Data flows through physicochemical modules sequentially, with each module importing data, evolving it, and exporting the updated data to the next downstream module. This is accomplished through various architectural abstractions designed to give RPTk true plug-and-play capabilities. A simple application of this architecture, as well as RPTk data flow and evolution, is demonstrated in Section 6 with an application consisting of two coupled physicochemical modules. The remaining sections describe this ongoing work in full, from system vision and design inception to full implementation. Section 3 describes the relevant software development processes used by the RPTk development team. These processes allow the team to manage system complexity and ensure stakeholder satisfaction. This section also details the work done on the RPTk ``black box'' and ``white box'' models, with a special focus on the separation of concerns between the RPTk user interface and application runtime. Section 4 and 5 discuss that application runtime component in more detail, and describe the dependencies, behavior, and rigorous testing of its constituent components.

McCaskey, Alex [ORNL; Billings, Jay Jay [ORNL; de Almeida, Valmor F [ORNL

2011-08-01

34

AN ADVANCED MODELING AND SIMULATION TOOL FOR ANALYSIS OF MECHATRONIC SYSTEMS  

Microsoft Academic Search

A new modeling and simulation tool, the Virtual Test Bed (VTB), is introduced. The VTB is a software environment that has been developed for design, analysis, and virtual prototyping of large-scale multi-technical systems. It has the capability of integrating models, which have been created in a variety of languages such as SPICE, ACSL ®, and SABER ®, into one simulation

Levent U. Gökdere; Charles W. Brice; Roger A. Dougal

35

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

NASA Technical Reports Server (NTRS)

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.

Corker, Kevin M.; Smith, Barry R.

1993-01-01

36

Modeling & Simulation  

NSDL National Science Digital Library

Modeling & Simulation is a journal published by The Society for Modeling and Simulation International. The Society has made its 2004 Modeling and Simulation Resource Guide available free to download. The directory provides descriptions and contact information for the many modeling and simulation software packages currently available, as well as listings for various modeling and simulation organizations worldwide. Two guest articles describe techniques for the application of real-time simulation in simulations that are complex. Previously published articles are also posted in the online archive.

37

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

NASA Astrophysics Data System (ADS)

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.

Jošt, D.; Škerlavaj, A.; Lipej, A.

2012-11-01

38

Advances in Network Simulation  

Microsoft Academic Search

ADVANTAGES OF A COMMON SIMULATORMultiprotocol network simulators provide a richopportunity for efficient experimentation. Disparateresearch efforts using a common simulation environmentcan yield substantial benefits, including. improved validation of the behavior of existingprotocols,. a rich infrastructure for developing new protocols,. the opportunity to study large-scale protocolinteraction in a controlled environment, and. easier comparison of results across researchefforts....

Lee Breslau; Deborah Estrin; Kevin R. Fall; Sally Floyd; John S. Heidemann; Ahmed Helmy; Polly Huang; Steven Mccanne; Kannan Varadhan; Ya Xu; Haobo Yu

2000-01-01

39

An open software framework for advancement of x-ray optics simulation and modeling  

NASA Astrophysics Data System (ADS)

Accurate physical-optics based simulation of emission, transport and use in experiments of fully- and partially-coherent X-ray radiation is essential for both designers and users of experiments at state-of-the-art light sources: low-emittance storage rings, energy-recovery linacs and free-electron lasers. To be useful for different applications, the simulations must include accurate physical models for the processes of emission, for the structures of X-ray optical elements, interaction of the radiation with samples, and propagation of scattered X-rays to a detector. Based on the "Synchrotron Radiation Workshop" (SRW) open source computer code, we are developing a simulation framework, including a graphical user interface, web interface for client-server simulations, data format for wave-optics based representation of partially-coherent X-ray radiation, and a dictionary for universal description of optical elements. Also, we are evaluating formats for sample and experimental data representation for different types of experiments and processing. The simulation framework will facilitate start-to-end simulations by different computer codes complementary to SRW, for example GENESIS and FAST codes for simulating self-amplified spontaneous emission, SHADOW and McXtrace geometrical ray-tracing codes, as well as codes for simulation of interaction of radiation with matter and data processing in experiments exploiting coherence of radiation. The development of the new framework is building on components developed for the Python-based RadTrack software, which is designed for loose coupling of multiple electron and radiation codes to enable sophisticated workflows. We are exploring opportunities for collaboration with teams pursuing similar developments at European Synchrotron Radiation Facility and the European XFEL.

Bruhwiler, David L.; Chubar, Oleg; Nagler, Robert; Krzywinski, Jacek; Boehnlein, Amber

2014-09-01

40

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

NASA Astrophysics Data System (ADS)

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.

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

41

Modelling method for complex induction machines used in naval applications using an advanced simulation concept  

Microsoft Academic Search

To be able to guarantee high availability of naval drives and power-supply systems, error scenarios have to be simulated. At this, the chosen set of differential equations has to model the physical behavior of complex induction machines used in naval applications, e.g. induction machines with 5- or 7-phases or with double-star stator windings including asymmetric faults which is not featured

Carsten Heising; Martin Oettmeier; Roman Bartelt; Jie Fang; Volker Staudt; Andreas Steimel

2009-01-01

42

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

43

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

Microsoft Academic Search

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

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

2011-01-01

44

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

SciTech Connect

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.

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

2000-06-29

45

Advancing predictive models for particulate formation in turbulent flames via massively parallel direct numerical simulations.  

PubMed

Combustion of fossil fuels is likely to continue for the near future due to the growing trends in energy consumption worldwide. The increase in efficiency and the reduction of pollutant emissions from combustion devices are pivotal to achieving meaningful levels of carbon abatement as part of the ongoing climate change efforts. Computational fluid dynamics featuring adequate combustion models will play an increasingly important role in the design of more efficient and cleaner industrial burners, internal combustion engines, and combustors for stationary power generation and aircraft propulsion. Today, turbulent combustion modelling is hindered severely by the lack of data that are accurate and sufficiently complete to assess and remedy model deficiencies effectively. In particular, the formation of pollutants is a complex, nonlinear and multi-scale process characterized by the interaction of molecular and turbulent mixing with a multitude of chemical reactions with disparate time scales. The use of direct numerical simulation (DNS) featuring a state of the art description of the underlying chemistry and physical processes has contributed greatly to combustion model development in recent years. In this paper, the analysis of the intricate evolution of soot formation in turbulent flames demonstrates how DNS databases are used to illuminate relevant physico-chemical mechanisms and to identify modelling needs. PMID:25024412

Bisetti, Fabrizio; Attili, Antonio; Pitsch, Heinz

2014-08-13

46

Advances in the simulation of toroidal gyro Landau fluid model turbulence  

SciTech Connect

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.

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

47

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

E-print Network

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

Engelmann, Christian

48

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

SciTech Connect

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.

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

49

2009 US-Japan Workshop on Advanced Simulation Methods in Plasma Physics Development of Reduced Computational Models for Alfvn Instabilities in  

E-print Network

to comprehensive model development since it inherently depends on verification against the more complete models in order to determinine ranges of validity. Reduced models are useful for such purposes as: rapid initial2009 US-Japan Workshop on Advanced Simulation Methods in Plasma Physics Development of Reduced

Ito, Atsushi

50

Advances in direct numerical simulation for MHD modeling of free surface flows  

Microsoft Academic Search

The utilization of FLiBe (LiF?BeF2) free-surface flow as a chamber protection scheme is considered in advanced nuclear fusion reactor. At the design of the nuclear fusion reactor from the viewpoint of thermofluid research, it would be very important to understand the influence of a magnetic field in turbulent free surface flow. On the other hand, turbulent free surface flow (called

Shin-ichi Satake; Tomoaki Kunugi; Sergey Smolentsev

2002-01-01

51

HiSIM2: Advanced MOSFET Model Valid for RF Circuit Simulation  

Microsoft Academic Search

The compact MOSFET model development trend leads to models based on the channel surface potential, allowing higher accuracy and a reduced number of model parameters. Among these, the Hiroshima University Semiconductor Technology Academic Research Center IGFET Model (HiSIM) solves the surface potentials with an efficient physically correct iteration procedure, thus avoiding additional approximations without any computer run-time penalty. It is

Mitiko Miura-Mattausch; Norio Sadachika; Dondee Navarro; Gaku Suzuki; Youichi Takeda; Masataka Miyake; Tomoyuki Warabino; Yoshio Mizukane; Ryosuke Inagaki; Tatsuya Ezaki; Hans Jürgen Mattausch; Tatsuya Ohguro; Takahiro Iizuka; Masahiko Taguchi; Shigetaka Kumashiro; Shunsuke Miyamoto

2006-01-01

52

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...

53

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 and the Theory of Queues, Ronald W. Wolff, Prentice Hall, 1989. 2. Discrete Stochastic Processes, Robert G

54

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

E-print Network

and properties (c) Generalizations: Nonhomogeneous, compound, conditional, & Markov- modulated Poisson Processes, Aca- demic Press, 2011. 1 #12;Topics 1. Poisson process (simple type of a point process model) (a) Point processes; Definition and modeling tool (b) Homogeneous Poisson Processes: Definition

55

Challenge problem and milestones for : Nuclear Energy Advanced Modeling and Simulation (NEAMS) waste Integrated Performance and Safety Codes (IPSC).  

SciTech Connect

This report describes the specification of a challenge problem and associated challenge milestones for the Waste Integrated Performance and Safety Codes (IPSC) supporting the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The NEAMS challenge problems are designed to demonstrate proof of concept and progress towards IPSC goals. The goal of the Waste IPSC is to develop an integrated suite of 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. To demonstrate proof of concept and progress towards these goals and requirements, a Waste IPSC challenge problem is specified that includes coupled thermal-hydrologic-chemical-mechanical (THCM) processes that describe (1) the degradation of a borosilicate glass waste form and the corresponding mobilization of radionuclides (i.e., the processes that produce the radionuclide source term), (2) the associated near-field physical and chemical environment for waste emplacement within a salt formation, and (3) radionuclide transport in the near field (i.e., through the engineered components - waste form, waste package, and backfill - and the immediately adjacent salt). The initial details of a set of challenge milestones that collectively comprise the full challenge problem are also specified.

Freeze, Geoffrey A.; Wang, Yifeng; Howard, Robert; McNeish, Jerry A.; Schultz, Peter Andrew; Arguello, Jose Guadalupe, Jr.

2010-09-01

56

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

E-print Network

: Nonhomogeneous, compound, conditional, & Markov- modulated Poisson Processes (d) Applications 2. Renewal theory. 1 #12;Topics 1. Poisson process (simple type of a point process model) (a) Point processes; Definition and modeling tool (b) Homogeneous Poisson Processes: Definition and properties (c) Generalizations

Lin, Xi

57

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

E-print Network

1-2 pm. References: 1. Stochastic Modeling and the Theory of Queues, Ronald W. Wol , Prentice Hall Processes, 2nd Edition, Sheldon Ross, Wiley, 1996. 1 #12;Topics 1. Introduction 2. Poisson processes (a) De

58

Recent Advances in Simulation of Dendritic Polymers  

SciTech Connect

Dendrimers and hyperbranched polymers represent a revolution in methodology for directed synthesis of monodisperse polymers with enormous possibility of novel architectures. They demonstrate the ability to attain micelle-like structures with distinct internal and external character. Furthermore, the polyfunctional character of dendrimers allows varied response to environment and promise as selective sensors, carrier for drugs, encapsulation of toxic chemicals and metals. One of the key problems is the characterization of the structures. Theory and simulation can be essential to provide and predict structure and properties. We present some recent advances in theory, modeling and simulation of dendritic polymers.

Cagin, Tahir; Miklis, Paul J.; Wang, Guofeng; Zamanakos, Georgios; Martin, Ryan; Li, Hao; Mainz, Daniel T.; Nagarajan, V.; Goddard, William A.

1999-05-11

59

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

SciTech Connect

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.

Hale, Steve

2013-09-11

60

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

SciTech Connect

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.

Brown, D L

2009-05-01

61

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

NASA Astrophysics Data System (ADS)

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.

Cheng, A.; Xu, K.

2013-12-01

62

PSP-SOI: An advanced surface potential based compact model of partially depleted SOI MOSFETs for circuit simulations  

Microsoft Academic Search

This paper reports recent progress in partially depleted (PD) SOI MOSFET modeling using a surface potential based approach. The new model is formulated within the framework of the latest industry standard bulk MOSFET model PSP. In addition to its physics-based formulation and scalability inherited from PSP, PSP-SOI captures SOI specific effects by including floating body simulation capability, parasitic body currents

W. Wu; X. Li; G. Gildenblat; G. O. Workman; S. Veeraraghavan; C. C. McAndrew; R. van Langevelde; G. D. J. Smit; A. J. Scholten; D. B. M. Klaassen; J. Watts

2009-01-01

63

Simulation methods for advanced scientific computing  

SciTech Connect

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, they produced a framework generalizing the famous Swendsen-Wang cluster algorithms for Ising and Potts models. For spin-glass-like problems, they demonstrated the effectiveness of an extension of the multicanonical method for the two-dimensional, random bond Ising model. For quantum mechanical systems, they generated a new method to compute the ground-state energy of systems of interacting electrons. They also improved methods to compute excited states when the diffusion quantum Monte Carlo method is used and to compute longer time dynamics when the stationary phase quantum Monte Carlo method is used.

Booth, T.E.; Carlson, J.A.; Forster, R.A. [and others

1998-11-01

64

14 CFR Appendix H to Part 121 - Advanced Simulation  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Advanced Simulation H Appendix H to Part 121 Aeronautics... Appendix H to Part 121—Advanced Simulation This appendix provides guidelines...simulator, as appropriate. Advanced Simulation Training Program For an...

2010-01-01

65

14 CFR Appendix H to Part 121 - Advanced Simulation  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Advanced Simulation H Appendix H to Part 121 Aeronautics... Appendix H to Part 121—Advanced Simulation This appendix provides guidelines...simulator, as appropriate. Advanced Simulation Training Program For an...

2012-01-01

66

14 CFR Appendix H to Part 121 - Advanced Simulation  

... 2014-01-01 false Advanced Simulation H Appendix H to Part 121 Aeronautics... Appendix H to Part 121—Advanced Simulation Link to an amendment published at...simulator, as appropriate. Advanced Simulation Training Program For an...

2014-01-01

67

14 CFR Appendix H to Part 121 - Advanced Simulation  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Advanced Simulation H Appendix H to Part 121 Aeronautics... Appendix H to Part 121—Advanced Simulation This appendix provides guidelines...simulator, as appropriate. Advanced Simulation Training Program For an...

2013-01-01

68

14 CFR Appendix H to Part 121 - Advanced Simulation  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Advanced Simulation H Appendix H to Part 121 Aeronautics... Appendix H to Part 121—Advanced Simulation This appendix provides guidelines...simulator, as appropriate. Advanced Simulation Training Program For an...

2011-01-01

69

Development of an Advanced Simulator to Model Mobility Control and Geomechanics during CO{sub 2} Floods  

SciTech Connect

The simulator is an isothermal, three-dimensional, four-phase, compositional, equation-of– state (EOS) simulator. We have named the simulator UTDOE-CO2 capable of simulating various recovery processes (i.e., primary, secondary waterflooding, and miscible and immiscible gas flooding). We include both the Peng-Robinson EOS and the Redlich-Kwong EOS models. A Gibbs stability test is also included in the model to perform a phase identification test to consistently label each phase for subsequent property calculations such as relative permeability, viscosity, density, interfacial tension, and capillary pressure. Our time step strategy is based on an IMPEC-type method (implicit pressure and explicit concentration). The gridblock pressure is solved first using the explicit dating of saturation-dependent terms. Subsequently, the material balance equations are solved explicitly for the total concentration of each component. The physical dispersion term is also included in the governing equations. The simulator includes (1) several foam model(s) for gas mobility control, (2) compositional relative permeability models with the hysteresis option, (3) corner point grid and several efficient solvers, (4) geomechanics module to compute stress field as the result of CO{sub 2} injection/production, (5) the format of commercial visualization software, S3graf from Science-soft Ltd., was implemented for user friendly visualization of the simulation results. All tasks are completed and the simulator was fully tested and delivered to the DOE office including a user’s guide and several input files and the executable for Windows Pcs. We have published several SPE papers, presented several posters, and one MS thesis is completed (V. Pudugramam, 2013) resulting from this DOE funded project.

Delshad, Mojdeh; Wheeler, Mary; Sepehrnoori, Kamy; Pope, Gary

2013-12-31

70

Overview of LMCT's advanced ladar signal simulator (ALASS)  

Microsoft Academic Search

The Advanced Ladar Signal Simulator (ALASS) is a comprehensive laser radar simulator that synthesizes ladar signals for complex three dimensional dynamic diffuse targets in the presence of a dynamic turbulent atmosphere. ALASS provides single realization random signals (speckle) or the associated mean signals (ensemble rough target average). ALASS is radiometrically correct, accurately models receiver diffraction and defocus for both coherent

Don Jacob; Phillip Gatt; Terry Nichols

2008-01-01

71

Supercomputer-based advanced ladar imaging simulator (ALIS)  

Microsoft Academic Search

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

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

2004-01-01

72

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

NASA Astrophysics Data System (ADS)

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.

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

73

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

NASA Astrophysics Data System (ADS)

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.

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

2011-08-01

74

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

NASA Astrophysics Data System (ADS)

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.

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

2006-05-01

75

Advanced Production Planning Models  

SciTech Connect

>This report describes the innovative modeling approach developed as a result of a 3-year Laboratory Directed Research and Development project. The overall goal of this project was to provide an effective suite of solvers for advanced production planning at facilities in the nuclear weapons complex (NWC). We focused our development activities on problems related to operations at the DOE's Pantex Plant. These types of scheduling problems appear in many contexts other than Pantex--both within the NWC (e.g., Neutron Generators) and in other commercial manufacturing settings. We successfully developed an innovative and effective solution strategy for these types of problems. We have tested this approach on actual data from Pantex, and from Org. 14000 (Neutron Generator production). This report focuses on the mathematical representation of the modeling approach and presents three representative studies using Pantex data. Results associated with the Neutron Generator facility will be published in a subsequent SAND report. The approach to task-based scheduling described here represents a significant addition to the literature for large-scale, realistic scheduling problems in a variety of production settings.

JONES,DEAN A.; LAWTON,CRAIG R.; KJELDGAARD,EDWIN A.; WRIGHT,STEPHEN TROY; TURNQUIST,MARK A.; NOZICK,LINDA K.; LIST,GEORGE F.

2000-12-01

76

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

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

77

Advanced Visualization Technology for Terascale Particle Accelerator Simulations  

E-print Network

Advanced Visualization Technology for Terascale Particle Accelerator Simulations Kwan-Liu Ma £ Greg Accelerator Center Lawrence Berkeley National Laboratory Abstract This paper presents two new hardware modeling of next- generation accelerator designs. The first technique, based on a hybrid rendering approach

Ma, Kwan-Liu

78

MODELING AND SIMULATING COOPERATION AND TEAMWORK  

Microsoft Academic Search

Cooperation and teamwork are aspects of human behavior that are crucial to realistic simulation of human behavior, but which have proven difficult to represent in the computer. New advances in cognitive simulation have enabled effective simulation of human behavior in individual tasks ('taskwork'), but teamwork requires still higher order cognitive abilities. The cognitive requirements for modeling and simulating cooperation and

Wayne W. Zachary; Bethlehem Pike

79

Dynamic Simulations of Advanced Fuel Cycles  

SciTech Connect

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 U.S. 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.

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

2011-03-01

80

Advances in the Modelling of Motorcycle Dynamics  

Microsoft Academic Search

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

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

2004-01-01

81

Reactive Potentials for Advanced Atomistic Simulations  

NASA Astrophysics Data System (ADS)

This article reviews recent advances in the development of reactive empirical force fields or potentials. In particular, we compare two widely used reactive potentials with variable-charge schemes that are desirable for multicomponent or multifunctional systems: the ReaxFF (reactive force field) and charge-optimized many-body (COMB) potentials. Several applications of these approaches in atomistic simulations that involve metal-based heterogeneous systems are also discussed.

Liang, Tao; Shin, Yun Kyung; Cheng, Yu-Ting; Yilmaz, Dundar E.; Vishnu, Karthik Guda; Verners, Osvalds; Zou, Chenyu; Phillpot, Simon R.; Sinnott, Susan B.; van Duin, Adri C. T.

2013-07-01

82

Center for Simulation of Advanced Rockets (CSAR): Gallery of Images from Advanced Rockets Simulations  

DOE Data Explorer

The Center for Simulation of Advanced Rockets (CSAR) is one of five university-based Centers of Excellence founded in 1997 and funded by the U.S. Department of Energy's Advanced Simulation and Computing program, whose objective is to enable accurate prediction of the performance, reliability, and safety of complex physical systems through computational simulation. CSAR's mission is to achieve this goal in the specific context of solid propellant rockets, which are of vital importance to the space launch industry. A particular focus for CSAR is on the reusable solid rocket motor (RSRM) that powers the U.S. Space Shuttle.

83

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

Microsoft Academic Search

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

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

2001-01-01

84

Hybrid and electric advanced vehicle systems (heavy) simulation  

NASA Technical Reports Server (NTRS)

A computer program to simulate hybrid and electric advanced vehicle systems (HEAVY) is described. It is intended for use early in the design process: concept evaluation, alternative comparison, preliminary design, control and management strategy development, component sizing, and sensitivity studies. It allows the designer to quickly, conveniently, and economically predict the performance of a proposed drive train. The user defines the system to be simulated using a library of predefined component models that may be connected to represent a wide variety of propulsion systems. The development of three models are discussed as examples.

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

1981-01-01

85

A Guide to Computer Simulations of Three Adaptive Instructional Models for the Advanced Instructional System Phases II and III. Final Report.  

ERIC Educational Resources Information Center

Computer simulations of three individualized adaptive instructional models (AIM) were undertaken to determine if these models function as prescribed in Air Force technical training programs. In addition, the project sought to develop a user's guide for effective understanding of adaptive models during field implementation. Successful simulations

Hansen, Duncan N.; And Others

86

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

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.

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

87

Advanced Modeling of Thermal Plasmas for Industrial Applications  

Microsoft Academic Search

Modeling results are presented for different industrial thermal plasma sources using a customized version of the commercial code FLUENT capable of 2D and 3D transient simulation with advanced CFD models that take into account turbulence effects using different approaches (Reynolds Stress Model and Large Eddy Simulation), transport of species and radiation (Discrete Ordinate Model with interaction between radiation and solid

Vittorio Colombo; Emanuele Ghedini

2006-01-01

88

Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event  

NASA Technical Reports Server (NTRS)

Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

Berndt, E. B.; Zavodsky, B. T.; Jedlovec, G. J.

2014-01-01

89

The Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event  

NASA Technical Reports Server (NTRS)

Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), Modern Era-Retrospective Analysis for Research and Applications (MERRA) reanalysis, and Rapid Refresh analyses.

Berndt, Emily; Zavodsky, Bradley; Jedlovec, Gary; Elmer, Nicholas

2013-01-01

90

Impact of the Assimilation of Hyperspectral Infrared Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event  

NASA Technical Reports Server (NTRS)

Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), North American Regional Reanalysis (NARR) reanalysis, and Rapid Refresh analyses.

Berndt, Emily B.; Zavodsky, Bradley T; Jedlovec, Gary J.; Elmer, Nicholas J.

2013-01-01

91

Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) verification and validation plan. version 1.  

SciTech Connect

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. To meet this objective, NEAMS Waste IPSC M&S capabilities will be applied to challenging spatial domains, temporal domains, multiphysics couplings, and multiscale couplings. A strategic verification and validation (V&V) goal is to establish evidence-based metrics for the level of confidence in M&S codes and capabilities. Because it is economically impractical to apply the maximum V&V rigor to each and every M&S capability, M&S capabilities will be ranked for their impact on the performance assessments of various components of the repository systems. Those M&S capabilities with greater impact will require a greater level of confidence and a correspondingly greater investment in V&V. This report includes five major components: (1) a background summary of the NEAMS Waste IPSC to emphasize M&S challenges; (2) the conceptual foundation for verification, validation, and confidence assessment of NEAMS Waste IPSC M&S capabilities; (3) specifications for the planned verification, validation, and confidence-assessment practices; (4) specifications for the planned evidence information management system; and (5) a path forward for the incremental implementation of this V&V plan.

Bartlett, Roscoe Ainsworth; Arguello, Jose Guadalupe, Jr.; Urbina, Angel; Bouchard, Julie F.; Edwards, Harold Carter; Freeze, Geoffrey A.; Knupp, Patrick Michael; Wang, Yifeng; Schultz, Peter Andrew; Howard, Robert (Oak Ridge National Laboratory, Oak Ridge, TN); McCornack, Marjorie Turner

2011-01-01

92

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)  

Microsoft Academic Search

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

Hyung Lee; Rich Johnson; Kimberlyn C. Moussesau

2011-01-01

93

Advanced Chemistry Basins Model  

SciTech Connect

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.

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

2003-02-13

94

The Consortium for Advanced Simulation of Light Water Reactors  

SciTech Connect

The Consortium for Advanced Simulation of Light Water Reactors (CASL) is a DOE Energy Innovation Hub for modeling and simulation of nuclear reactors. It brings together an exceptionally capable team from national labs, industry and academia that will apply existing modeling and simulation capabilities and develop advanced capabilities to create a usable environment for predictive simulation of light water reactors (LWRs). This environment, designated as the Virtual Environment for Reactor Applications (VERA), will incorporate science-based models, state-of-the-art numerical methods, modern computational science and engineering practices, and uncertainty quantification (UQ) and validation against data from operating pressurized water reactors (PWRs). It will couple state-of-the-art fuel performance, neutronics, thermal-hydraulics (T-H), and structural models with existing tools for systems and safety analysis and will be designed for implementation on both today's leadership-class computers and the advanced architecture platforms now under development by the DOE. CASL focuses on a set of challenge problems such as CRUD induced power shift and localized corrosion, grid-to-rod fretting fuel failures, pellet clad interaction, fuel assembly distortion, etc. that encompass the key phenomena limiting the performance of PWRs. It is expected that much of the capability developed will be applicable to other types of reactors. CASL's mission is to develop and apply modeling and simulation capabilities to address three critical areas of performance for nuclear power plants: (1) reduce capital and operating costs per unit energy by enabling power uprates and plant lifetime extension, (2) reduce nuclear waste volume generated by enabling higher fuel burnup, and (3) enhance nuclear safety by enabling high-fidelity predictive capability for component performance.

Ronaldo Szilard; Hongbin Zhang; Doug Kothe; Paul Turinsky

2011-10-01

95

Aviation Safety Simulation Model  

NASA Technical Reports Server (NTRS)

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.

Houser, Scott; Yackovetsky, Robert (Technical Monitor)

2001-01-01

96

Validation of simulation models  

Microsoft Academic Search

This is a tutorial paper on validation of simulation models. Included in this tutorial are what is meant by validation, the problem dependent characteristics of simulation model validation, descriptions of the various validation techniques and their use and a discussion on the statistics used in validation techniques (but not the detailed statistical tests themselves).

Robert G. Sargent

1979-01-01

97

Spacecraft Simulation Toolkit (SST): an advanced distributed simulation framework for supporting the space warfighter  

NASA Astrophysics Data System (ADS)

The spacecraft simulation toolkit (SST) is an advanced software architecture for the modeling and simulation of spacecraft and spacecraft interactions based upon state-of- the-art techniques, the Khoros visual programming environment, and accurate physical phenomenology. The SST simulates spacecraft systems and subsystems; the user virtually 'builds' a spacecraft by selecting and integrating components, duplicating real world actions. The models in the SST perform algorithmic simulation of spacecraft functions. System design and simulation databases provide both the knowledge base within which detailed characteristics of the system are described and an efficient means to store simulation results for additional analysis. Representation of the real-world, natural environment is provided. Khoros also provides integrated data analysis and software development tools. The SST is being configured to meet a broad range of requirements in design, technology development, systems acquisition, on- orbit operations, and spacecraft operator training.

de Jonckheere, Richard K.; Franklin, Terri L.; Wilson, David D.

1997-06-01

98

Advances in Simulation of Wave Interaction with Extended MHD Phenomena  

SciTech Connect

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.

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

99

Advances in Simulation of Wave Interactions with Extended MHD Phenomena  

SciTech Connect

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.

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

100

Simulating advanced life support systems to test integrated control approaches  

NASA Astrophysics Data System (ADS)

Simulations allow for testing of life support control approaches before hardware is designed and built. Simulations also allow for the safe exploration of alternative control strategies during life support operation. As such, they are an important component of any life support research program and testbed. This paper describes a specific advanced life support simulation being created at NASA Johnson Space Center. It is a discrete-event simulation that is dynamic and stochastic. It simulates all major components of an advanced life support system, including crew (with variable ages, weights and genders), biomass production (with scalable plantings of ten different crops), water recovery, air revitalization, food processing, solid waste recycling and energy production. Each component is modeled as a producer of certain resources and a consumer of certain resources. The control system must monitor (via sensors) and control (via actuators) the flow of resources throughout the system to provide life support functionality. The simulation is written in an object-oriented paradigm that makes it portable, extensible and reconfigurable.

Kortenkamp, D.; Bell, S.

101

ADVANCED MIXING MODELS  

SciTech Connect

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?

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

2011-02-14

102

The Market Acceptance of Advanced Automotive Technologies (MA3T) Model  

E-print Network

The Market Acceptance of Advanced Automotive Technologies (MA3T) Model Research Brief Oak Ridge: Energy Environment Safety Security Vehicle Technologies T he Market Acceptance of Advanced Automotive T simulates market demand for advanced vehicle technologies by representing relevant attributes

103

ADVANCED MIXING MODELS  

SciTech Connect

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

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

2008-11-13

104

Models and Simulations  

NSDL National Science Digital Library

Scientists use models and simulations to help them visualize, explain, and make predictions and hypotheses about the structures, properties, and behaviors of phenomena (e.g., objects, materials, processes, systems). The extremely small size and complexity

Krajcik, Joseph S.; Sutherland, Leeann M.; Stevens, Shawn Y.

2009-10-14

105

Theory Modeling and Simulation  

SciTech Connect

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.

Shlachter, Jack [Los Alamos National Laboratory

2012-08-23

106

ADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING  

E-print Network

ADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING WATER REACTOR AND THE HEAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Advanced Boiling Water Reactor - General Description . . . . . . . . . . . 3 2.1 Modifications-Dimensional Continuity Wave Equation for Boiling Mixtures . . 10 3.2.1 Derivation of Equation

Mitchell, John E.

107

Recent advances in lunar base simulation  

NASA Astrophysics Data System (ADS)

This article reports about the results of the latest computer runs of a lunar base simulation model. The lunar base consists of 20 facilities for lunar mining, processing and fabrication. The infrastructure includes solar and nuclear power plants, a central workshop, habitat and farm. Lunar products can be used for construction of solar power systems (SPS) or other spacecraft at several space locations. The simulation model evaluates the mass, energy and manpower flows between the elements of the system as well as system cost and cost of products on an annual basis for a given operational period. The 1983 standard model run over a fifty-years life cycle (beginning about the year 2000) was accomplished for a mean annual production volume of 78 180 Mg of hardware products for export resulting in average specific manufacturing cost of 8.4 $/kg and total annual cost of 1.25 billion dollars during the life cycle. The reference space transportation system uses LOX/LH 2 propulsion for which at the average 210 500 Mg LOX per year is produced on the moon. The sensitivity analysis indicates the importance of bootstrapping as well as the influence of market size, space transportation cost and specific resources demand on the mean lunar manufacturing cost. The option using lunar resources turns out to be quite attractive from the economical viewpoint. Systems analysis by this lunar base model and further trade-offs will be a useful tool to confirm this.

Johenning, B.; Koelle, H. H.

108

Interoperable Technologies for Advanced Petascale Simulations  

SciTech Connect

Our final report on the accomplishments of ITAPS at Stony Brook during period covered by the research award includes component service, interface service and applications. On the component service, we have designed and implemented a robust functionality for the Lagrangian tracking of dynamic interface. We have migrated the hyperbolic, parabolic and elliptic solver from stage-wise second order toward global second order schemes. We have implemented high order coupling between interface propagation and interior PDE solvers. On the interface service, we have constructed the FronTier application programer's interface (API) and its manual page using doxygen. We installed the FronTier functional interface to conform with the ITAPS specifications, especially the iMesh and iMeshP interfaces. On applications, we have implemented deposition and dissolution models with flow and implemented the two-reactant model for a more realistic precipitation at the pore level and its coupling with Darcy level model. We have continued our support to the study of fluid mixing problem for problems in inertial comfinement fusion. We have continued our support to the MHD model and its application to plasma liner implosion in fusion confinement. We have simulated a step in the reprocessing and separation of spent fuels from nuclear power plant fuel rods. We have implemented the fluid-structure interaction for 3D windmill and parachute simulations. We have continued our collaboration with PNNL, BNL, LANL, ORNL, and other SciDAC institutions.

Li, Xiaolin [SUNY at Stony Brook] [SUNY at Stony Brook

2013-01-14

109

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

Microsoft Academic Search

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

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

2001-01-01

110

Pilot evaluation of an advanced hingeless rotor XY-15 simulation  

NASA Technical Reports Server (NTRS)

A piloted simulation of an advanced hingeless rotor XV-15 tilt-rotor aircraft was carried out. The evaluation was made by a pilot from NASA-Ames who had previous experience flying a simulation of the current gimballed rotor NASA/Army XV-15. It was pointed out that some modifications to the force feel system were needed in order to provide rapid force trimming during rapid maneuvers. Some additional tailoring of the SCAS system was required to achieve good nap-of-the-earth performance. Overall pilot opinion on the hingeless rotor XV-15 tilt rotor was favorable. Brief discussion on the mathematical models and the simulator configuration are presented. The maneuvers and pilot comments are given along with some engineering comments.

Mcveigh, M. A.

1977-01-01

111

Advancing the Art of Simulation in the Social Sciences  

Microsoft Academic Search

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

Robert Axelrod

1997-01-01

112

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...

113

Mobile advanced simulation for primary care pediatricians: Spanish Experience  

E-print Network

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

Manstein, Dietmar J.

114

Multi-physics and Multi-scale Modelling in Cardiovascular Physiology: Advanced User Methods for Simulation of Biological Systems with ANSYS\\/CFX  

Microsoft Academic Search

This work encompasses together a number of diverse disciplines (physiology, biomechanics, fluid mechanics and simulation)\\u000a in order to develop a predictive model of the behaviour of a prosthetic heart valve in vivo. The application of simulation,\\u000a for the study of other cardiovascular problems, such as blood clotting is also discussed. A commercial, finite volume, computational\\u000a fluid dynamics (CFD) code (ANSYS\\/CFX)

Vanessa Díaz-zuccarini; D. Rafirou; D. Rodney Hose; Patricia V. Lawford; A. J. Narracott

2007-01-01

115

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

Microsoft Academic Search

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

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

1997-01-01

116

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

The recent Nevada Earthquake (M=6) produced an extraordinary set of crustal guided waves. In this study, we examine the three-component data at all the USArray stations in terms of how well existing models perform in predicting the various phases, Rayleigh waves, Love waves, and Pnl waves. To establish the source parameters, we applied the Cut and Paste Code up to distance of 5° for an average local crustal model which produced a normal mechanism (strike=35°,dip=41°,rake=-85°) at a depth of 9 km and Mw=5.9. Assuming this mechanism, we generated synthetics at all distances for a number of 1D and 3D models. The Pnl observations fit the synthetics for the simple models well both in timing (VPn=7.9km/s) and waveform fits out to a distance of about 5°. Beyond this distance a great deal of complexity can be seen to the northwest apparently caused by shallow subducted slab material. These paths require considerable crustal thinning and higher P-velocities. Small delays and advances outline the various tectonic province to the south, Colorado Plateau, etc. with velocities compatible with that reported on by Song et al.(1996). Five-second Rayleigh waves (Airy Phase) can be observed throughout the whole array and show a great deal of variation ( up to 30s). In general, the Love waves are better behaved than the Rayleigh waves. We are presently adding higher frequency to the source description by including source complexity. Preliminary inversions suggest rupture to northeast with a shallow asperity. We are, also, inverting the aftershocks to extend the frequencies to 2 Hz and beyond following the calibration method outlined in Tan and Helmberger (2007). This will allow accurate directivity measurements for events with magnitude larger than 3.5. Thus, we will address the energy decay with distance as s function of frequency band for the various source types.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-04-15

117

Precision Casting via Advanced Simulation and Manufacturing  

NASA Technical Reports Server (NTRS)

A two-year program was conducted to develop and commercially implement selected casting manufacturing technologies to enable significant reductions in the costs of castings, increase the complexity and dimensional accuracy of castings, and reduce the development times for delivery of high quality castings. The industry-led R&D project was cost shared with NASA's Aerospace Industry Technology Program (AITP). The Rocketdyne Division of Boeing North American, Inc. served as the team lead with participation from Lockheed Martin, Ford Motor Company, Howmet Corporation, PCC Airfoils, General Electric, UES, Inc., University of Alabama, Auburn University, Robinson, Inc., Aracor, and NASA-LeRC. The technical effort was organized into four distinct tasks. The accomplishments reported herein. Task 1.0 developed advanced simulation technology for core molding. Ford headed up this task. On this program, a specialized core machine was designed and built. Task 2.0 focused on intelligent process control for precision core molding. Howmet led this effort. The primary focus of these experimental efforts was to characterize the process parameters that have a strong impact on dimensional control issues of injection molded cores during their fabrication. Task 3.0 developed and applied rapid prototyping to produce near net shape castings. Rocketdyne was responsible for this task. CAD files were generated using reverse engineering, rapid prototype patterns were fabricated using SLS and SLA, and castings produced and evaluated. Task 4.0 was aimed at developing technology transfer. Rocketdyne coordinated this task. Casting related technology, explored and evaluated in the first three tasks of this program, was implemented into manufacturing processes.

1997-01-01

118

A Virtual Engineering Framework for Simulating Advanced Power System  

SciTech Connect

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.

Mike Bockelie; Dave Swensen; Martin Denison; Stanislav Borodai

2008-06-18

119

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

High-Resolution Source Parameters using Calibration from Ambient Seismic Noise (ASN) Zhongwen Zhan, Shengji Wei, Sidao Ni, and Don V. Helmberger Abstract Several new methods have been developed to retrieve local Green's functions based on the cross-correlation of ambient seismic noise (station-to-station) and conventional (source-to-station) inversions. The latter methods provide the most broadband results but require accurate source parameters for phase-delay recovery which depends on the starting model. Considerable progress is being made in providing such information from 3D modeling, Tape et al. (2008), using Adjoint Tomography. But to match waveforms for the recent Chino Hills event still requires shifting synthetics to align on data. This means that it is difficult to use 3D simulations to refine source locations in near-real time. We can avoid the 3D problems by applying the CAP method and storing shifts from past events, Tan (2006), and/or using ASN, Shapiro et al. (2005), to predict lags for surface waves. Here, we directly compare results from CAP predictions with ASN results using stations near the Chino Hills event. We use the same SC seismic model as used in the Library of Earthquakes to generate Green's functions for noise (single force) for comparison with ASN correlations and allow Cap delays. We apply these delays or corrections to determine precise Centroid locations.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2009-04-30

120

Advancements in engineering turbulence modeling  

NASA Technical Reports Server (NTRS)

Some new developments in two-equation models and second order closure models are presented. Two-equation models (k-epsilon models) have been widely used in computational fluid dynamics (CFD) for engineering problems. Most of low-Reynolds number two-equation models contain some wall-distance damping functions to account for the effect of wall on turbulence. However, this often causes the confusion and difficulties in computing flows with complex geometry and also needs an ad hoc treatment near the separation and reattachment points. A set of modified two-equation models is proposed to remove the aforementioned shortcomings. The calculations using various two-equation models are compared with direct numerical simulations of channel flow and flat boundary layers. Development of a second order closure model is also discussed with emphasis on the modeling of pressure related correlation terms and dissipation rates in the second moment equations. All the existing models poorly predict the normal stresses near the wall and fail to predict the 3-D effect of mean flow on the turbulence (e.g. decrease in the shear stress caused by the cross flow in the boundary layer). The newly developed second order near-wall turbulence model is described and is capable of capturing the near-wall behavior of turbulence as well as the effect of 3-D mean flow on the turbulence.

Shih, T.-H.

1991-01-01

121

Rotor systems research aircraft simulation mathematical model  

NASA Technical Reports Server (NTRS)

An analytical model developed for evaluating and verifying advanced rotor concepts is discussed. The model was used during in both open loop and real time man-in-the-loop simulation during the rotor systems research aircraft design. Future applications include: pilot training, preflight of test programs, and the evaluation of promising concepts before their implementation on the flight vehicle.

Houck, J. A.; Moore, F. L.; Howlett, J. J.; Pollock, K. S.; Browne, M. M.

1977-01-01

122

Advanced Mirror & Modelling Technology Development  

NASA Technical Reports Server (NTRS)

The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.

Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

2014-01-01

123

Brush seal numerical simulation: Concepts and advances  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

124

Modeling Tool Advances Rotorcraft Design  

NASA Technical Reports Server (NTRS)

Continuum Dynamics Inc. (CDI), founded in 1979, specializes in advanced engineering services, including fluid dynamic modeling and analysis for aeronautics research. The company has completed a number of SBIR research projects with NASA, including early rotorcraft work done through Langley Research Center, but more recently, out of Ames Research Center. NASA Small Business Innovation Research (SBIR) grants on helicopter wake modeling resulted in the Comprehensive Hierarchical Aeromechanics Rotorcraft Model (CHARM), a tool for studying helicopter and tiltrotor unsteady free wake modeling, including distributed and integrated loads, and performance prediction. Application of the software code in a blade redesign program for Carson Helicopters, of Perkasie, Pennsylvania, increased the payload and cruise speeds of its S-61 helicopter. Follow-on development resulted in a $24 million revenue increase for Sikorsky Aircraft Corporation, of Stratford, Connecticut, as part of the company's rotor design efforts. Now under continuous development for more than 25 years, CHARM models the complete aerodynamics and dynamics of rotorcraft in general flight conditions. CHARM has been used to model a broad spectrum of rotorcraft attributes, including performance, blade loading, blade-vortex interaction noise, air flow fields, and hub loads. The highly accurate software is currently in use by all major rotorcraft manufacturers, NASA, the U.S. Army, and the U.S. Navy.

2007-01-01

125

Agent-based Modeling and Simulation  

Microsoft Academic Search

Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. Computational advances have made possible a growing number of agent-based models across a variety of application domains. Applications range from modeling agent behavior in the stock market, supply chains, and consumer markets, to predicting the spread of epidemics, mitigating the threat of bio-warfare,

Charles M. Macal; Michael J. North

2009-01-01

126

Space shuttle simulation model  

NASA Technical Reports Server (NTRS)

The effects of atmospheric turbulence in both horizontal and near horizontal flight, during the return of the space shuttle, are important for determining design, control, and 'pilot-in-the-loop' effects. A nonrecursive model (based on von Karman spectra) for atmospheric turbulence along the flight path of the shuttle orbiter was developed which provides for simulation of instantaneous vertical and horizontal gusts at the vehicle center-of-gravity, and also for simulation of instantaneous gust gradients. Based on this model, the time series for both gusts and gust gradients were generated and stored on a series of magnetic tapes which are entitled shuttle simulation turbulence tapes (SSTT). The time series are designed to represent atmospheric turbulence from ground level to an altitude of 10,000 meters. The turbulence generation procedure is described as well as the results of validating the simulated turbulence. Conclusions and recommendations are presented and references cited. The tabulated one dimensional von Karman spectra and the results of spectral and statistical analyses of the SSTT are contained in the appendix.

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

1980-01-01

127

Advanced radiometric and interferometric milimeter-wave scene simulations  

NASA Astrophysics Data System (ADS)

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.

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

1993-12-01

128

Advanced radiometric and interferometric milimeter-wave scene simulations  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

129

Advanced simulation code for alpha spectrometry  

E-print Network

A Monte Carlo code, known as AASI, is developed for simulating energy spectra in alpha spectrometry. The code documented here is a comprehensive package where all the major processes affecting the spectrum are included. A unique feature of the code is its ability to take into account coincidences between the particles emitted from the source. Simulations and measurements highlight the importance of coincidences in high-resolution alpha spectrometry. To show the validity of the simulated results, comparisons with measurements and other simulation codes are presented.

T. Siiskonen; R. Pollanen

2005-05-04

130

Advanced wellbore thermal simulator GEOTEMP2 research report  

SciTech Connect

The development of the GEOTEMP2 wellbore thermal simulator is described. The major technical features include a general purpose air and mist drilling simulator and a two-phase steam flow simulator that can model either injection or production.

Mitchell, R.F.

1982-02-01

131

Revolutions in energy through modeling and simulation  

SciTech Connect

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.

Tatro, M.; Woodard, J.

1998-08-01

132

PRATHAM: Parallel Thermal Hydraulics Simulations using Advanced Mesoscopic Methods  

SciTech Connect

At the Oak Ridge National Laboratory, efforts are under way to develop a 3D, parallel LBM code called PRATHAM (PaRAllel Thermal Hydraulic simulations using Advanced Mesoscopic Methods) to demonstrate the accuracy and scalability of LBM for turbulent flow simulations in nuclear applications. The code has been developed using FORTRAN-90, and parallelized using the message passing interface MPI library. Silo library is used to compact and write the data files, and VisIt visualization software is used to post-process the simulation data in parallel. Both the single relaxation time (SRT) and multi relaxation time (MRT) LBM schemes have been implemented in PRATHAM. To capture turbulence without prohibitively increasing the grid resolution requirements, an LES approach [5] is adopted allowing large scale eddies to be numerically resolved while modeling the smaller (subgrid) eddies. In this work, a Smagorinsky model has been used, which modifies the fluid viscosity by an additional eddy viscosity depending on the magnitude of the rate-of-strain tensor. In LBM, this is achieved by locally varying the relaxation time of the fluid.

Joshi, Abhijit S [ORNL] [ORNL; Jain, Prashant K [ORNL] [ORNL; Mudrich, Jaime A [ORNL] [ORNL; Popov, Emilian L [ORNL] [ORNL

2012-01-01

133

Advanced Combustion Modeling for Complex Turbulent Flows  

NASA Technical Reports Server (NTRS)

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.

Ham, Frank Stanford

2005-01-01

134

Advances in Edge-Diffraction Modeling for Virtual-Acoustic  

E-print Network

Advances in Edge-Diffraction Modeling for Virtual-Acoustic Simulations Paul Thomas Calamia there has been growing interest in modeling sound propagation in complex, three-dimensional (3D) virtual of virtual spaces. To this end, this thesis focuses on improving the physical and perceptual realism of sound

135

Multiphase flow in the advanced fluid dynamics model  

Microsoft Academic Search

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.

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

1988-01-01

136

UTILITY OF MECHANISTIC MODELS FOR DIRECTING ADVANCED SEPARATIONS RESEARCH & DEVELOPMENT ACTIVITIES: Electrochemically Modulated Separation Example  

SciTech Connect

The objective for this work was to demonstrate the utility of mechanistic computer models designed to simulate actinide behavior for use in efficiently and effectively directing advanced laboratory R&D activities associated with developing advanced separations methods.

Schwantes, Jon M.

2009-06-01

137

Safety evaluation using behavioral simulation models  

Microsoft Academic Search

This paper describes a design environment called ADEPT (advanced design environment prototype tool) which enables designers to assess the dependability of systems early in the design process using behavioral simulation models. ADEPT is an interactive graphical design environment which allows design and analysis of systems throughout the entire design cycle. ADEPT supports functional verification, performance evaluation, and dependability analysis early

Anup K. Ghosh; Barry W. Johnson; Joseph A. Profeta

1996-01-01

138

Models, Simulations, and Games: A Survey.  

ERIC Educational Resources Information Center

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…

Shubik, Martin; Brewer, Garry D.

139

Rapid implementation of advanced constitutive models  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

140

Advanced modeling of high intensity accelerators  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goals of this project were three-fold: (1) to develop a new capability, based on high performance (parallel) computers, to perform large scale simulations of high intensity accelerators; (2) to apply this capability to modeling high intensity accelerators under design at LANL; and (3) to use this new capability to improve the understanding of the physics of intense charge particle beams, especially in regard to the issue of beam halo formation. All of these goals were met. In particular, the authors introduced split-operator methods as a powerful and efficient means to simulate intense beams in the presence of rapidly varying accelerating and focusing fields. They then applied these methods to develop scaleable, parallel beam dynamics codes for modeling intense beams in linacs, and in the process they implemented a new three-dimensional space charge algorithm. They also used the codes to study a number of beam dynamics issues related to the Accelerator Production of Tritium (APT) project, and in the process performed the largest simulations to date for any accelerator design project. Finally, they used the new modeling capability to provide direction and validation to beam physics studies, helping to identify beam mismatch as a major source of halo formation in high intensity accelerators. This LDRD project ultimately benefited not only LANL but also the US accelerator community since, by promoting expertise in high performance computing and advancing the state-of-the-art in accelerator simulation, its accomplishments helped lead to approval of a new DOE Grand Challenge in Computational Accelerator Physics.

Ryne, R.D.; Habib, S.; Wangler, T.P.

1998-11-01

141

Micromechanical modeling of advanced materials  

SciTech Connect

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.

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

1994-04-01

142

Intracranial injectable tumor model: technical advancements.  

PubMed

Background and Objectives?Few simulation models are available that provide neurosurgical trainees with the challenge of distorted skull base anatomy despite increasing importance in the acquisition of safe microsurgical and endoscopic techniques. We have previously reported a unique training model for skull base neurosurgery where a polymer is injected into a cadaveric head where it solidifies to mimic a skull base tumor for resection. This model, however, required injection of the polymer under direct surgical vision via a complicated alternative approach to that being studied, prohibiting its uptake in many neurosurgical laboratories. Conclusion?We report our updated skull base tumor model that is contrast-enhanced and may be easily and reliably injected under fluoroscopic guidance. We have identified a map of burr holes and injection corridors available to place tumor at various intracranial sites. Additionally, the updated tumor model allows for the creation of mass effect, and we detail the variation of polymer preparation to mimic different tumor properties. These advancements will increase the practicality of the tumor model and ideally influence neurosurgical standards of training. PMID:25276597

Gragnaniello, Cristian; Gagliardi, Filippo; Chau, Anthony M T; Nader, Remi; Siu, Alan; Litvack, Zachary; Luca, Bruno De; Seex, Kevin; Mortini, Pietro; Caputy, Anthony J; Al-Mefty, Ossama

2014-10-01

143

ADVISOR: a systems analysis tool for advanced vehicle modeling  

Microsoft Academic Search

This paper provides an overview of Advanced Vehicle Simulator (ADVISOR)—the US Department of Energy’s (DOE’s) ADVISOR written in the MATLAB\\/Simulink environment and developed by the National Renewable Energy Laboratory. ADVISOR provides the vehicle engineering community with an easy-to-use, flexible, yet robust and supported analysis package for advanced vehicle modeling. It is primarily used to quantify the fuel economy, the performance,

T. Markel; A. Brooker; T. Hendricks; V. Johnson; K. Kelly; B. Kramer; M O’Keefe; S. Sprik; K. Wipke

2002-01-01

144

Measurement and modeling of advanced coal conversion processes  

SciTech Connect

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.

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

145

State of the Art Assessment of Simulation in Advanced Materials Development  

NASA Technical Reports Server (NTRS)

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.

Wise, Kristopher E.

2008-01-01

146

Advanced power plant training simulator for VVER-440/V230 nuclear power plants  

SciTech Connect

An advanced, workstation based, nuclear power plant simulator has been developed for use in training the operational staff of the Bohunice Nuclear Power Plant. This training simulator uses state-of- the-art computer hardware and software and provides the capability to simultaneously include six members of the power plant operating staff in the training sessions. A detailed reactor model has been developed, representing the Bohunice VVER-44O/V230 plants, for use with the RELAP5 simulation software. In addition, a comprehensive validation program has been completed that compares the simulation results of the advanced simulator with the results from a current VVER-44O/V230 simulator. A summary of the training features and capabilities of the simulator is also provided.

Shier, W.; Kennett, R. [Brookhaven National Lab., Upton, NY (United States); Vaclav, E.; Gieci, A. [Nuclear Power Research Inst. Trnava, Inc. (Slovakia)

1996-11-01

147

Computational Frameworks for Advanced Combustion Simulations  

Microsoft Academic Search

\\u000a Computational frameworks can significantly assist in the construction, extension and maintenance of simulation codes. As the\\u000a nature of problems addressed by computational means has grown in complexity, such frameworks have evolved to incorporate a\\u000a commensurate degree of sophistication, both in terms of the numerical algorithms that they accommodate as well as the software\\u000a architectural discipline they impose on their users.

J. Ray; R. Armstrong; C. Safta; B. J. Debusschere; B. A. Allan; H. N. Najm

148

Simulating CCDs for the Chandra Advanced CCD Imaging Spectrometer  

E-print Network

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.

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

2001-10-31

149

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

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.

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

2011-12-01

150

Alignment and Initial Operation of an Advanced Solar Simulator  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

151

Partnerships to Advance Learning in Science: Java Simulations  

NSDL National Science Digital Library

Provided by Iowa State University, the Partnerships to Advance Learning in Science: Java Simulations Web site contains several interactive science simulations. Visitors can explore advection, the energy budget, adiabatic processes, and radiation. For example, the mountain simulation teaches about adiabatic processes by allowing users to adjust various parameters such as temperature, dew point, mountain slope, and cloud base altitude. The simulation then blows a leaf over the mountain and moves it according to what was entered. Each activity has accompanying directions and questions if interested.

1999-01-01

152

Advances in beryllium powder consolidation simulation  

SciTech Connect

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.

Reardon, B.J.

1998-12-01

153

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)

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.

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

2003-02-01

154

REQUIREMENTS FOR THE CALIBRATION OF TRAFFIC SIMULATION MODELS  

Microsoft Academic Search

The recent emphasis on utilising advanced technologies to make more efficient use of existing transportation infrastructure, coupled with the continuing advances in desktop computing technologies, has created an environment in which traffic simulation models have the potential to provide a cost-effective , objective, and flexible approach for assessing design and management alternatives. However, the models must be demonstrated to be

Bruce R. Hellinga

155

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

Earthquake source parameters underpin several aspects of nuclear explosion monitoring. Such aspects are: calibration of moment magnitudes (including coda magnitudes) and magnitude and distance amplitude corrections (MDAC); source depths; discrimination by isotropic moment tensor components; and waveform modeling for structure (including waveform tomography). This project seeks to improve methods for and broaden the applicability of estimating source parameters from broadband waveforms using the Cut-and-Paste (CAP) methodology. The CAP method uses a library of Green’s functions for a one-dimensional (1D, depth-varying) seismic velocity model. The method separates the main arrivals of the regional waveform into 5 windows: Pnl (vertical and radial components), Rayleigh (vertical and radial components) and Love (transverse component). Source parameters are estimated by grid search over strike, dip, rake and depth and seismic moment or equivalently moment magnitude, MW, are adjusted to fit the amplitudes. Key to the CAP method is allowing the synthetic seismograms to shift in time relative to the data in order to account for path-propagation errors (delays) in the 1D seismic velocity model used to compute the Green’s functions. The CAP method has been shown to improve estimates of source parameters, especially when delay and amplitude biases are calibrated using high signal-to-noise data from moderate earthquakes, CAP+.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-06-17

156

The advanced computational testing and simulation toolkit (ACTS)  

SciTech Connect

During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts, and tool maturity. This paper presents a brief introduction to the functionality available in ACTS.

Drummond, L.A.; Marques, O.

2002-05-21

157

Simulation model verification and validation  

Microsoft Academic Search

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

Robert G. Sargent

1991-01-01

158

Verifying and validating simulation models  

Microsoft Academic Search

This paper discusses verification and validation 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; and a recommended procedureispresented.

Robert G. Sargent

1996-01-01

159

Verifying and validating simulation models  

Microsoft Academic Search

This paper discusses verification and validation of simulation models. The different approaches to deciding model validity am 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; and a recommended procedure is presented.

Robert G. Sargent

1996-01-01

160

Simulation model verification and validation  

Microsoft Academic Search

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

Robert G. Sargent

1991-01-01

161

Advanced Review Mathematical models of  

E-print Network

and as a repressor, specifies the spatial arrangement of the muscle, nerve, and skin tissues.13 Graded distribution). Each of these gradients arises from asymmetries in the unfertilized egg. The origin of the Bcd gradient. Following egg fertilization, the bcd mRNA © 2012 Wiley Periodicals, Inc. #12;Advanced Review wires

Shvartsman, Stanislav "Stas"

162

Analytical and simulator study of advanced transport  

NASA Technical Reports Server (NTRS)

An analytic methodology, based on the optimal-control pilot model, was demonstrated for assessing longitidunal-axis handling qualities of transport aircraft in final approach. Calibration of the methodology is largely in terms of closed-loop performance requirements, rather than specific vehicle response characteristics, and is based on a combination of published criteria, pilot preferences, physical limitations, and engineering judgment. Six longitudinal-axis approach configurations were studied covering a range of handling qualities problems, including the presence of flexible aircraft modes. The analytical procedure was used to obtain predictions of Cooper-Harper ratings, a solar quadratic performance index, and rms excursions of important system variables.

Levison, W. H.; Rickard, W. W.

1982-01-01

163

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

This quarter, we have focused on several tasks: (1) Building a high-quality catalog of earthquake source parameters for the Middle East and East Asia. In East Asia, we computed source parameters using the CAP method for a set of events studied by Herrman et al., (MRR, 2006) using a complete waveform technique. Results indicated excellent agreement with the moment magnitudes in the range 3.5 -5.5. Below magnitude 3.5 the scatter increases. For events with more than 2-3 observations at different azimuths, we found good agreement of focal mechanisms. Depths were generally consistent, although differences of up to 10 km were found. These results suggest that CAP modeling provides estimates of source parameters at least as reliable as complete waveform modeling techniques. However, East Asia and the Yellow Sea Korean Paraplatform (YSKP) region studied are relatively laterally homogeneous and may not benefit from the CAP method’s flexibility to shift waveform segments to account for path-dependent model errors. A more challenging region to study is the Middle East where strong variations in sedimentary basin, crustal thickness and crustal and mantle seismic velocities greatly impact regional wave propagation. We applied the CAP method to a set of events in and around Iran and found good agreement between estimated focal mechanisms and those reported by the Global Centroid Moment Tensor (CMT) catalog. We found a possible bias in the moment magnitudes that may be due to the thick low-velocity crust in the Iranian Plateau. (2) Testing Methods on a Lifetime Regional Data Set. In particular, the recent 2/21/08 Nevada Event and Aftershock Sequence occurred in the middle of USArray, producing over a thousand records per event. The tectonic setting is quite similar to Central Iran and thus provides an excellent testbed for CAP+ at ranges out to 10°, including extensive observations of crustal thinning and thickening and various Pnl complexities. Broadband modeling in 1D, 2D, and 3D will be presented. (3) Shallow Crustal Structure and Sparse Network Source Inversions for Southern California. We conducted a detailed test of a recently developed technique, CAPloc, in recovering source parameters including location and depth based on tomographic maps. We tested two-station solutions against 160 well determined events which worked well except for paths crossing deep basins and along mountain ridges.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2008-10-17

164

PIXE simulation: Models, methods and technologies  

SciTech Connect

The simulation of PIXE (Particle Induced X-ray Emission) is discussed in the context of general-purpose Monte Carlo systems for particle transport. Dedicated PIXE codes are mainly concerned with the application of the technique to elemental analysis, but they lack the capability of dealing with complex experimental configurations. General-purpose Monte Carlo codes provide powerful tools to model the experimental environment in great detail, but so far they have provided limited functionality for PIXE simulation. This paper reviews recent developments that have endowed the Geant4 simulation toolkit with advanced capabilities for PIXE simulation, and related efforts for quantitative validation of cross sections and other physical parameters relevant to PIXE simulation.

Batic, M. [INFN Sezione di Genova, Via Dodecaneso 33, 16146 Genova, Italy and Jozef Stefan Institute, Jamova cesta 39, Ljubljana 1000 (Slovenia); Pia, M. G.; Saracco, P. [INFN Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Weidenspointner, G. [Max-Planck-Institut Halbleiterlabor, Otto-Hahn-Ring 6, 81739 Muenchen (Germany) and Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Garching 85748 (Germany)

2013-04-19

165

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

SciTech Connect

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.?

Freshley, M.; Hubbard, S.; Flach, G.; Freedman, V.; Agarwal, D.; Andre, B.; Bott, Y.; Chen, X.; Davis, J.; Faybishenko, B.; Gorton, I.; Murray, C.; Moulton, D.; Meyer, J.; Rockhold, M.; Shoshani, A.; Steefel, C.; Wainwright, H.; Waichler, S.

2012-09-28

166

ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS  

SciTech Connect

Abstract We conduct a detailed test of a recently developed technique, CAPloc, in recovering source parameters from a few stations against results from a large broadband network in Southern California. The method uses a library of 1D Green’s functions which are broken into segments and matched to waveform observations with adjustable timing shifts. These shifts can be established by calibration against a distribution of well-located earthquakes and assembled in tomographic images for predicting various phase-delays. Synthetics generated from 2D cross-sections through these models indicates that 1D synthetic waveforms are sufficient in modeling but simply shifted in time for most hard-rock sites. This simplification allows the source inversion for both mechanism and location to easily obtain by grid search. We test one-station mechanisms for 160 events against the array for both PAS and GSC which have data since 1960. While individual solutions work well (about 90%), joint solutions produce more reliable and defensible results. Inverting for both mechanism and location also works well except for certain complex paths across deep basins and along mountain ridges.

Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

2009-01-27

167

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

NASA Technical Reports Server (NTRS)

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.

Pepin, Gerard R.; Hager, E. Paul

1991-01-01

168

Modeling and Simulation of Nuclear Fuel Materials  

SciTech Connect

We review the state of modeling and simulation of nuclear fuels with emphasis on the most widely used nuclear fuel, UO2. The hierarchical scheme presented represents a science-based approach to modeling nuclear fuels by progressively passing information in several stages from ab initio to continuum levels. Such an approach is essential to overcome the challenges posed by radioactive materials handling, experimental limitations in modeling extreme conditions and accident scenarios and small time and distance scales of fundamental defect processes. When used in conjunction with experimental validation, this multiscale modeling scheme can provide valuable guidance to development of fuel for advanced reactors to meet rising global energy demand.

Devanathan, Ram [Pacific Northwest National Laboratory (PNNL); Van Brutzel, Laurent [LSCE/CEA, Gif-sur-Yvette, France; Chartier, Alain [LSCE/CEA, Gif-sur-Yvette, France; Christine, Gueneau [LSCE/CEA, Gif-sur-Yvette, France; Mattsson, Ann [Sandia National Laboratories (SNL); Tikare, Veena [Sandia National Laboratories (SNL); Bartel, Timothy [Sandia National Laboratories (SNL); Besmann, Theodore M [ORNL; Stan, Marius [Los Alamos National Laboratory (LANL); Van Uffelen, Paul [Institute for Transuranium Elements, Germany

2010-01-01

169

Design and simulation of advanced charge recovery piezoactuator drivers  

NASA Astrophysics Data System (ADS)

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.

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

2010-10-01

170

AFDM: An Advanced Fluid-Dynamics Model  

SciTech Connect

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.

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

171

Advanced Modeling of Thermal Plasmas for Industrial Applications  

NASA Astrophysics Data System (ADS)

Modeling results are presented for different industrial thermal plasma sources using a customized version of the commercial code FLUENT capable of 2D and 3D transient simulation with advanced CFD models that take into account turbulence effects using different approaches (Reynolds Stress Model and Large Eddy Simulation), transport of species and radiation (Discrete Ordinate Model with interaction between radiation and solid surfaces). Simulations results are presented in order to show the capabilities of this modeling tool, which is very useful for the design of a wide range of atmospheric pressure thermal plasmas devices and related assisted processes, such as: ICPTs with injection of powders for spheroidization, DC twin-torch transferred arc plasma systems for waste treatment, DC non-transferred arc torch for plasma spraying and DC transferred arc torch for high quality plasma cutting.

Colombo, Vittorio; Ghedini, Emanuele

2006-10-01

172

I. Introduction Simulation Modeling  

E-print Network

, figure of merit, design of experiments, software testing, software validation, program referability, experimentation technique, simulation methodology, and software engineering. Key Words and Phrases: assessment, program efficiency, code verification, software reliability, software robustness, software certification

Tesfatsion, Leigh

173

AN ADVANCED COLLABORATIVE INFRASTRUCTURE FOR THE REAL-TIME COMPUTATIONAL STEERING OF LARGE CFD SIMULATIONS  

Microsoft Academic Search

Advances in computer processing power and networking over the past few years have brought a significant change to the modelling and simulation of complex phenomena. Problems that formerly could only be tackled in batch mode, with their results visualized after- wards, can now be monitored whilst in progress using graphical means, in certain cases it is even possible to alter

Pierre Boulanger; Manuel Julio Garcia; Curtis Badke; Jeff Ryan

2006-01-01

174

Lessons Learned From Dynamic Simulations of Advanced Fuel Cycles  

SciTech Connect

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.

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

2009-04-01

175

Validating simulation models  

Microsoft Academic Search

In this paper we give a general introduction to model validation, define the various validation techniques, discuss conceptual and operational validity, and present a recommended model validation procedure.

Robert G. Sargent

1983-01-01

176

Voltage and temperature dynamic simulations for advanced Battery Management Systems  

Microsoft Academic Search

Successful introduction of Plug-in Electrical Vehicles (PEV) increases the requirements for advanced on-board Battery Management Systems (BMS) significantly. Modern BMS provides the driver for a number of important indications, such as remaining operation time, adaptive State-of-Charge and State-of-Health. The core of an advanced BMS is a mathematical model for the battery (pack). However, the high complexity and the large amount

D. Danilov; A. Lyedovskikh; P. H. L. Notten

2011-01-01

177

Advanced accelerator simulation research: miniaturizing accelerators from kilometers to meters  

E-print Network

as well as more mainstream problems in accelerator physics, such as the electron cloud instability in this quest. One of the goals of the SciDAC Accelerator Modeling Project is to develop code and software-scale experiments. We describe the existing hierarchy of software tools for modelling advanced accelerators, how

Geddes, Cameron Guy Robinson

178

Advanced Simulation of Coupled Earthquake and Tsunami Events  

NASA Astrophysics Data System (ADS)

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.

Behrens, Joern

2013-04-01

179

Genome Reshuffling for Advanced Intercross Permutation (GRAIP): Simulation and permutation for advanced intercross population analysis  

SciTech Connect

Background: Advanced intercross lines (AIL) are segregating populations created using a multi-generation breeding protocol for fine mapping complex trait loci (QTL) in mice and other organisms. Applying QTL mapping methods for intercross and backcross populations, often followed by na ve permutation of individuals and phenotypes, does not account for the effect of AIL family structure in which final generations have been expanded and leads to inappropriately low significance thresholds. The critical problem with na ve mapping approaches in AIL populations is that the individual is not an exchangeable unit. Methodology/Principal Findings: The effect of family structure has immediate implications for the optimal AIL creation (many crosses, few animals per cross, and population expansion before the final generation) and we discuss these and the utility of AIL populations for QTL fine mapping. We also describe Genome Reshuffling for Advanced Intercross Permutation, (GRAIP) a method for analyzing AIL data that accounts for family structure. GRAIP permutes a more interchangeable unit in the final generation crosses - the parental genome - and simulating regeneration of a permuted AIL population based on exchanged parental identities. GRAIP determines appropriate genome-wide significance thresholds and locus-specific Pvalues for AILs and other populations with similar family structures. We contrast GRAIP with na ve permutation using a large densely genotyped mouse AIL population (1333 individuals from 32 crosses). A na ve permutation using coat color as a model phenotype demonstrates high false-positive locus identification and uncertain significance levels, which are corrected using GRAIP. GRAIP also detects an established hippocampus weight locus and a new locus, Hipp9a. Conclusions and Significance: GRAIP determines appropriate genome-wide significance thresholds and locus-specific Pvalues for AILs and other populations with similar family structures. The effect of family structure has immediate implications for the optimal AIL creation and we discuss these and the utility of AIL populations.

Pierce, Jeremy [University of Tennessee Health Science Center, Memphis; Broman, Karl [Johns Hopkins University; Lu, Lu [University of Tennessee Health Science Center, Memphis; Chesler, Elissa J [ORNL; Zhou, Guomin [University of Tennessee Health Science Center, Memphis; Airey, David [University of Tennessee Health Sciences Center, Memphis, TN; Birmingham, Amanda [Dharmacon, Inc.; Williams, Robert [University of Tennessee Health Science Center, Memphis

2008-04-01

180

Requirements for advanced simulation of nuclear reactor and chemicalseparation plants.  

SciTech Connect

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.

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

181

An Advanced Scattered Moonlight Model  

NASA Astrophysics Data System (ADS)

Correcting and predicting the flux coming from the background sky is a crucial aspect of observational astronomy. We have developed a sky background model for this purpose, and it is the most complete and universal sky model that we know of to date. The largest natural source of light at night in the optical is the Moon, and it is a major contributor to the astronomical sky background. An improved spectroscopic scattered moonlight model, which is applicable from 0.3 to 2.5 ?m has been developed and studied with a set of FORS1 spectra and a dedicated X-shooter dataset. To our knowledge, this is the first spectroscopic model extending into the infrared and it has been tested for many lunar phases and geometries of the Moon and target observations.

Jones, Amy M.; Noll, Stefan; Kausch, Wolfgang; Szyszka, Cezary; Kimeswenger, Stefan

2014-06-01

182

Building an advanced climate model: Program plan for the CHAMMP (Computer Hardware, Advanced Mathematics, and Model Physics) Climate Modeling Program  

SciTech Connect

The issue of global warming and related climatic changes from increasing concentrations of greenhouse gases in the atmosphere has received prominent attention during the past few years. The Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP) Climate Modeling Program is designed to contribute directly to this rapid improvement. The goal of the CHAMMP Climate Modeling Program is to develop, verify, and apply a new generation of climate models within a coordinated framework that incorporates the best available scientific and numerical approaches to represent physical, biogeochemical, and ecological processes, that fully utilizes the hardware and software capabilities of new computer architectures, that probes the limits of climate predictability, and finally that can be used to address the challenging problem of understanding the greenhouse climate issue through the ability of the models to simulate time-dependent climatic changes over extended times and with regional resolution.

Not Available

1990-12-01

183

ADVANCED SCREENING MODEL FOR COMPLEX TERRAIN APPLICATIONS  

EPA Science Inventory

A methodology has been developed to use the advanced techniques of the Complex Terrain Dispersion Model in situations where on-site meteorological measurements are limited or unavailable. This approach, known as CTSCREEN, uses actual source and terrain characteristics to model pl...

184

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

Microsoft Academic Search

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

Daniel A. Saylor; Mark Bowden; James Buford

2006-01-01

185

Integrating advanced materials simulation techniques into an automated data analysis workflow at the Spallation Neutron Source  

SciTech Connect

This presentation will review developments on the integration of advanced modeling and simulation techniques into the analysis step of experimental data obtained at the Spallation Neutron Source. A workflow framework for the purpose of refining molecular mechanics force-fields against quasi-elastic neutron scattering data is presented. The workflow combines software components to submit model simulations to remote high performance computers, a message broker interface for communications between the optimizer engine and the simulation production step, and tools to convolve the simulated data with the experimental resolution. A test application shows the correction to a popular fixed-charge water model in order to account polarization effects due to the presence of solvated ions. Future enhancements to the refinement workflow are discussed. This work is funded through the DOE Center for Accelerating Materials Modeling.

Borreguero Calvo, Jose M [ORNL] [ORNL; Campbell, Stuart I [ORNL] [ORNL; Delaire, Olivier A [ORNL] [ORNL; Doucet, Mathieu [ORNL] [ORNL; Goswami, Monojoy [ORNL] [ORNL; Hagen, Mark E [ORNL] [ORNL; Lynch, Vickie E [ORNL] [ORNL; Proffen, Thomas E [ORNL] [ORNL; Ren, Shelly [ORNL] [ORNL; Savici, Andrei T [ORNL] [ORNL; Sumpter, Bobby G [ORNL] [ORNL

2014-01-01

186

Automatic programming of simulation models  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

187

Accurate mask model for advanced nodes  

NASA Astrophysics Data System (ADS)

Standard OPC models consist of a physical optical model and an empirical resist model. The resist model compensates the optical model imprecision on top of modeling resist development. The optical model imprecision may result from mask topography effects and real mask information including mask ebeam writing and mask process contributions. For advanced technology nodes, significant progress has been made to model mask topography to improve optical model accuracy. However, mask information is difficult to decorrelate from standard OPC model. Our goal is to establish an accurate mask model through a dedicated calibration exercise. In this paper, we present a flow to calibrate an accurate mask enabling its implementation. The study covers the different effects that should be embedded in the mask model as well as the experiment required to model them.

Zine El Abidine, Nacer; Sundermann, Frank; Yesilada, Emek; Ndiaye, El Hadji Omar; Mishra, Kushlendra; Paninjath, Sankaranarayanan; Bork, Ingo; Buck, Peter; Toublan, Olivier; Schanen, Isabelle

2014-07-01

188

Model Standards Advance the Profession  

ERIC Educational Resources Information Center

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…

Journal of Staff Development, 2011

2011-01-01

189

Progress in modeling and simulation.  

PubMed

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

Kindler, E

1998-01-01

190

Advanced Simulation in Undergraduate Pilot Training: Motion System Development.  

National Technical Information Service (NTIS)

The production of kinesthetic information pertinent to the aircraft piloting task by use of motion base devices relies on mathematical models which are developed in a largely empirical manner and evaluated in a subjective manner. The ASUPT simulator conta...

G. J. Kron

1975-01-01

191

Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova  

SciTech Connect

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.

Glimm, James

2008-06-24

192

Flight simulation testing of advanced composites for supersonic cruise aircraft applications  

NASA Technical Reports Server (NTRS)

The goal of this program is to characterize advanced composite systems before and after exposures to simulated supersonic cruise environments for real times of up to 50,000 hours. Fatigue data for specimens tested at various temperatures and stress ratios are presented. The changes in properties and the degradation mechanisms during high temperature aging are discussed and illustrated using metallographic and fractographic techniques. Initial results of long term flight simulation tests are presented and compared with wearout model predictions based on accelerated flight simulation exposures.

Haskins, J. F.; Kerr, J. R.; Stein, B. A.

1977-01-01

193

Incorporation of RAM techniques into simulation modeling  

NASA Astrophysics Data System (ADS)

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.

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

1995-01-01

194

Advanced studies on Simulation Methodologies for very Complicated Fracture Phenomena  

NASA Astrophysics Data System (ADS)

Although nowadays, computational techniques are well developed, for Extremely Complicated Fracture Phenomena, they are still very difficult to simulate, for general engineers, researchers. To overcome many difficulties in those simulations, we have developed not only Simulation Methodologies but also theoretical basis and concepts. We sometimes observe extremely complicated fracture patterns, especially in dynamic fracture phenomena such as dynamic crack branching, kinking, curving, etc. For examples, although the humankind, from primitive men to modern scientists such as Albert Einstein had watched the post-mortem patterns of dynamic crack branching, the governing condition for the onset of the phenomena had been unsolved until our experimental study. From in these studies, we found the governing condition of dynamic crack bifurcation, as follows. When the total energy flux per unit time into a propagating crack tip reaches the material crack resistance, the crack braches into two cracks [total energy flux criterion]. The crack branches many times whenever the criterion is satisfied. Furthermore, the complexities also arise due to their time-dependence and/or their-deformation dependence. In order to make it possible to simulate such extremely complicated fracture phenomena, we developed many original advanced computational methods and technologies. These are (i)moving finite element method based on Delaunay automatic triangulation (MFEMBOAT), path independent,(ii) equivalent domain integral expression of the dynamic J integral associated with a continuous auxiliary function,(iii) Mixed phase path-prediction mode simulation, (iv) implicit path prediction criterion. In this paper, these advanced computational methods are thoroughly explained together with successful comparison with the experimental results. Since multiple dynamic crack branching phenomena may be most complicated fracture due to complicated fracture paths, and its time dependence (transient), this simulation and numerical results are mainly explained.

Nishioka, Toshihisa

2010-06-01

195

MICS-Asia II: Modeling gaseous pollutants and evaluating an advanced modeling system over East Asia  

Microsoft Academic Search

An advanced modeling system with a “one-atmosphere” perspective, Models-3\\/Community Multi-scale Air Quality (CMAQ) modeling system, driven by MM5\\/NCEP reanalysis data as the meteorology, and GEOS-Chem outputs as boundary values was applied to simulate the O3, and other gaseous pollutants (SO2 and NO2) evolution among other atmospheric chemicals for July 2001. Comparisons had been made with other models in the MICS-II

Joshua S. Fu; Carey J. Jang; David G. Streets; Zuopan Li; Roger Kwok; Zhiwei Han

2008-01-01

196

Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova  

SciTech Connect

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.

James Glimm

2009-06-04

197

Advanced visualization technology for terascale particle accelerator simulations  

Microsoft Academic Search

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

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

2002-01-01

198

Modeling, Simulation, and Visualization  

E-print Network

current representation) and dynamic re-planning during model execution. · Go beyond if ­ then planning the occurrence of events to situational awareness by logging the events in the Situational Awareness data base & Information Sciences Division Argonne, IL 60439-4832 phone: 630.252.5308 vang@anl.gov LBC Sponsor:Mr. Morris G

Kemner, Ken

199

Advances in Modeling Exploding Bridgewire Initiation  

SciTech Connect

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.

Hrousis, C A; Christensen, J S

2010-03-10

200

Verification of Computer Simulation Models  

Microsoft Academic Search

The problem of validating computer simulation models of industrial systems has received only limited attention in the management science literature. The purpose of this paper is to consider the problem of validating computer models in the light of contemporary thought in the fields of philosophy of science, economic theory, and statistics. In order to achieve this goal we have attempted

Thomas H. Naylor; J. M. Finger

1967-01-01

201

The Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event  

NASA Technical Reports Server (NTRS)

Tropopause folds are identified by warm, dry, high-potential vorticity, ozone-rich air and are one explanation for damaging non-convective wind events. Could improved model representation of stratospheric air and associated tropopause folding improve non-convective wind forecasts and high wind warnings? The goal of this study is to assess the impact of assimilating Hyperspectral Infrared (IR) profiles on forecasting stratospheric air, tropopause folds, and associated non-convective winds: (1) AIRS: Atmospheric Infrared Sounder (2) IASI: Infrared Atmospheric Sounding Interferometer (3) CrIMSS: Cross-track Infrared and Microwave Sounding Suite

Brendt. Emily; Zavodsky, Bradley; Jedlovec, Gary; Elmer, Nicholas

2014-01-01

202

Combustion modeling in advanced gas turbine systems  

SciTech Connect

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.

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

203

Verification And Validation Of Simulation Models  

Microsoft Academic Search

The Hierarchical Modeling and Simulation System (HI-MASS) is a prototype modeling and simulation system that supports modeling based on the Hierarchical Control Flow Graph Model paradigm and simulation execution using a sequential synchronous simulation algorithm. The prototype is an object oriented C++ based system designed for a Unix environment and implemented using freely available software tools. Models are specified using

Douglas G. Fritz; Robert G. Sargent; Thorsten Daum

1995-01-01

204

A Hardware in the Loop module in an IEC61850 Co-Simulation Platform for advanced substation  

E-print Network

in choosing their Intelligent Electronic Devices (IED) (e.g. protection relay, power meter ...). HoweverA Hardware in the Loop module in an IEC61850 Co- Simulation Platform for advanced substation cannot be checked directly, modeling is helpful. In our research study we propose a co-simulation

Boyer, Edmond

205

ADVISOR 2.1: a user-friendly advanced powertrain simulation using a combined backward\\/forward approach  

Microsoft Academic Search

ADVISOR 2.1 is the latest version of the National Renewable Energy Laboratory's advanced vehicle simulator. It was first developed in 1994 to support the US Department of Energy hybrid propulsion system program and is designed to be accurate, fast, flexible, easily sharable, and easy to use. This paper presents the model, focusing on its combination of forward- and backward-facing simulation

Keith B. Wipke; Matthew R. Cuddy; Steven D. Burch

1999-01-01

206

ADVANCED COMPUTATIONAL MODELING OF MILITARY INCINERATORS  

Microsoft Academic Search

Incineration is being used or is planned as a primary destruction technology of stockpiles of chemical warfare agents (CWA) in the United States. Computer modeling tools may play an important role in reducing the time, cost and technical risk of using incineration. A simulation workbench is being developed to assist the chemical demilitarization community. The workbench will consist of models

Martin K. Denison; Chris J. Montgomery; Adel F. Sarofim; Michael J. Bockelie; Alfred G. Webster; Robert J. Mellon

2002-01-01

207

treedyn3 forest simulation model  

Microsoft Academic Search

The treedyn3 forest simulation model is a process model of tree growth, carbon and nitrogen dynamics in a single-species, even-aged forest stand. It is based on the treedyn model. Major changes include the computation of sun angle and radiation as a function of latitude and day of the year, the closed-form integration of canopy production as a function of day

Hartmut Bossel

1996-01-01

208

Recent advances of strong-strong beam-beam simulation  

SciTech Connect

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.

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

2004-09-15

209

Stochastic models: theory and simulation.  

SciTech Connect

Many problems in applied science and engineering involve physical phenomena that behave randomly in time and/or space. Examples are diverse and include turbulent flow over an aircraft wing, Earth climatology, material microstructure, and the financial markets. Mathematical models for these random phenomena are referred to as stochastic processes and/or random fields, and Monte Carlo simulation is the only general-purpose tool for solving problems of this type. The use of Monte Carlo simulation requires methods and algorithms to generate samples of the appropriate stochastic model; these samples then become inputs and/or boundary conditions to established deterministic simulation codes. While numerous algorithms and tools currently exist to generate samples of simple random variables and vectors, no cohesive simulation tool yet exists for generating samples of stochastic processes and/or random fields. There are two objectives of this report. First, we provide some theoretical background on stochastic processes and random fields that can be used to model phenomena that are random in space and/or time. Second, we provide simple algorithms that can be used to generate independent samples of general stochastic models. The theory and simulation of random variables and vectors is also reviewed for completeness.

Field, Richard V., Jr.

2008-03-01

210

Advanced Technology Vehicle Modeling in PERE (Physical Emission Rate Estimator).  

National Technical Information Service (NTIS)

This study proposes a modeling methodology for light duty advanced technology vehicles including those powered by: Advanced gasoline internal combustion engine; Advanced diesel internal combustion engines; Hybrid electric and gasoline/diesel powertrains; ...

E. Nam

2004-01-01

211

Graphics simulation and training aids for advanced teleoperation  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

212

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

E-print Network

2009 US-Japan Workshop on Advanced Simulation Methods in Plasma Physics Plasma Particle Simulation-resolution calculation saving computer resources. In AMR, hierarchical computational cells are generated or removed

Ito, Atsushi

213

Process/equipment co-simulation for designe and analysis of advanced energy systems  

SciTech Connect

b s t r a c t The grand challenge facing the power and energy industries is the development of efficient, environmentally friendly, and affordable technologies for next-generation energy systems. To provide solutions for energy and the environment, the U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) and its research partners in industry and academia are relying increasingly on the use of sophisticated computer-aided process design and optimization tools. In this paper, we describe recent progress toward developing an Advanced Process Engineering Co-Simulator (APECS) for the high-fidelity design, analysis, and optimization of energy plants. The APECS software system combines steady-state process simulation with multiphysics-based equipment simulations, such as those based on computational fluid dynamics (CFD). These co-simulation capabilities enable design engineers to optimize overall process performance with respect to complex thermal and fluid flow phenomena arising in key plant equipment items, such as combustors, gasifiers, turbines, and carbon capture devices. In this paper we review several applications of the APECS co-simulation technology to advanced energy systems, including coal-fired energy plants with carbon capture. This paper also discusses ongoing co-simulation R&D activities and challenges in areas such as CFD-based reduced-order modeling, knowledge management, advanced analysis and optimization, and virtual plant co-simulation. Continued progress in co-simulation technology – through improved integration, solution, and deployment – will have profound positive impacts on the design and optimization of high-efficiency, near-zero emission fossil energy systems.

Zitney, S.

2010-01-01

214

Automatic programming of simulation models  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

215

Economic Analysis. Computer Simulation Models.  

ERIC Educational Resources Information 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…

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

216

Software Partitioning Schemes for Advanced Simulation Computer Systems. Final Report.  

ERIC Educational Resources Information Center

Conducted to design software partitioning techniques for use by the Air Force to partition a large flight simulator program for optimal execution on alternative configurations, this study resulted in a mathematical model which defines characteristics for an optimal partition, and a manually demonstrated partitioning algorithm design which…

Clymer, S. J.

217

Presented by CASL: The Consortium for Advanced Simulation  

E-print Network

/strain/fatigue � Oxidation � Hydride concentration � Transport loads � Fretting wear � Clad diameter increase � Cladding A DOE Energy Innovation Hub for Modeling and Simulation of Nuclear Reactors Doug Kothe Director, CASL concerns: � Cladding integrity � Fretting � Corrosion/ CRUD � Hydriding � Creep � Fuel-cladding mechanical

218

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

ERIC Educational Resources Information Center

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…

Nordmark, Staffan

1984-01-01

219

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

SciTech Connect

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.

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

2008-06-30

220

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

NASA Astrophysics Data System (ADS)

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).

Adam, Konstantinos; Neureuther, Andrew R.

2002-07-01

221

Modeling and Simulation for Safeguards  

SciTech Connect

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.

Swinhoe, Martyn T. [Los Alamos National Laboratory

2012-07-26

222

The HWVP availability simulation model  

SciTech Connect

This report described the hanford Waste Vitrification Plant simualtion model (HWVP).The model was utilized to simulate the performance and repair of remote handling equipment utilizied at the vitrification plant. The simulation model demonstrates that the HWVP has an availability of {approx} 85%. It also shows that both the MC and CDC cranes have a high utilization factor of {approx} 70%. This means that the crane`s idle time of {approx} 30% may not be sufficient to meet off-normal events such as canister rework. A study is recommended to optimize the crane operations in these areas. The ST/ET crane`s utilization factor is 16%, indicating that it can meet upset conditions. The analysis also shows that the canyon crane has a utilization factor of 29%, or it is idle 61% of the time. This large amount of inactive time demonstrates that the crane can service failed equipment without affecting production.

Reisdorf, J.; Sienko, F.; Melville, D.; Gogg, T.

1994-12-31

223

Time-domain analysis simulation for advanced tracking  

NASA Astrophysics Data System (ADS)

TASAT is a complete end-to-end system simulation of tracking and pointing systems. It can currently model ground-based (GB), space-based (SB), and kinetic energy weapon (KEW) systems at a very high level of fidelity to assess system performance and design tradeoffs. It is primarily a time-domain analysis tool, but it can also perform frequency-domain analysis for performance and stability analysis. TASAT was built as a modular set of interacting routines that permit much more than end-to-end analysis. Specifically, subsystem and even component level analyses are available. The code treats all aspects of tracking and pointing systems using realistic, anchored imagery in a multiwavelength simulation. Some of the functions modeled include orbit propagation or launch trajectories, image rendering with high fidelity scattering calculations, atmospheric or optical blur point-spread functions (PSFs), image formation via convolution, realistic focal plane sensors including dead bands, sensor noise, and analog-to- digital conversion, and control system response. For GB applications, the atmospheric model is a novel treatment of the time average PSF after application of an adaptive optics system. Also, atmospheric tilt is modeled exactly. The code has applications beyond GB, SB, and KEW systems. It will treat imaging systems, tactical and strategic surveillance systems, and radar range gating. The paper provides an overview of the simulation architecture and presents results from analyses of each of the principal systems modeled in TASAT.

Riker, James F.; Crockett, Gregg A.; Brunson, Richard L.

1992-11-01

224

Simulation and modeling of homogeneous, compressed turbulence  

NASA Technical Reports Server (NTRS)

Low Reynolds number homogeneous turbulence undergoing low Mach number isotropic and one-dimensional compression was simulated by numerically solving the Navier-Stokes equations. The numerical simulations were performed on a CYBER 205 computer using a 64 x 64 x 64 mesh. A spectral method was used for spatial differencing and the second-order Runge-Kutta method for time advancement. A variety of statistical information was extracted from the computed flow fields. These include three-dimensional energy and dissipation spectra, two-point velocity correlations, one-dimensional energy spectra, turbulent kinetic energy and its dissipation rate, integral length scales, Taylor microscales, and Kolmogorov length scale. Results from the simulated flow fields were used to test one-point closure, two-equation models. A new one-point-closure, three-equation turbulence model which accounts for the effect of compression is proposed. The new model accurately calculates four types of flows (isotropic decay, isotropic compression, one-dimensional compression, and axisymmetric expansion flows) for a wide range of strain rates.

Wu, C. T.; Ferziger, J. H.; Chapman, D. R.

1985-01-01

225

Simulating advanced reactor transients to support the NRC (Nuclear Regulatory Commission)  

SciTech Connect

Work has been performed to determine a modeling methodology for an advanced evolutionary pressurized water reactor (PWR), specifically the Westinghouse AP-600. In the past, simulation of nuclear plant thermal-hydraulic performance with state-of-the-art computer codes like the US Nuclear Regulatory Commission's (NRC's) best-estimate code, TRAC has provided significant insights into plant performance. The NRC has taken on the task of reviewing and commenting on new design concepts with a strategy of reviewing conceptual designs, identifying major licensing issues, identifying design features needing verification, and issuing safety evaluation reports. TRAC-PF1/MOD2 and other state-of-the-art thermal-hydraulic simulation codes may be employed to support future NRC research in the area of advanced reactor transient analysis. Efforts at Los Alamos National Laboratory are focused on developing a preliminary TRAC input model for an advanced PWR to provide an understanding of advanced reactor concepts and issues of potential safety concern to the NRC.

Jenks, R.P.; Stumpf, H.J. (Los Alamos National Lab., NM (USA))

1989-01-01

226

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

SciTech Connect

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.

Kissel, L

2009-04-01

227

Advanced Simulation & Computing FY09-FY10 Implementation Plan Volume 2, Rev. 0  

SciTech Connect

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the safety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future nonnuclear 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.

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

2008-04-30

228

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

SciTech Connect

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.

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

2007-09-13

229

Theory, modeling and simulation: Annual report 1993  

SciTech Connect

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.

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

1994-07-01

230

A Standard Kinematic Model for Flight Simulation at NASA Ames  

NASA Technical Reports Server (NTRS)

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.

Mcfarland, R. E.

1975-01-01

231

Simulation Model Driven Engineering for Manufacturing Cell  

E-print Network

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

Paris-Sud XI, Université de

232

Simulation Framework for Teaching in Modeling and Simulation Areas  

ERIC Educational Resources Information Center

Simulation is the process of executing a model that describes a system with enough detail; this model has its entities, an internal state, some input and output variables and a list of processes bound to these variables. Teaching a simulation language such as general purpose simulation system (GPSS) is always a challenge, because of the way it…

De Giusti, Marisa Raquel; Lira, Ariel Jorge; Villarreal, Gonzalo Lujan

2008-01-01

233

JIFT Workshop `Advanced Simulation Methods in Plasma Physics'at NIFS, Dec.14-16 Particle Simulation AnalysisParticle Simulation Analysis  

E-print Network

JIFT Workshop `Advanced Simulation Methods in Plasma Physics'at NIFS, Dec.14-16 Particle SimulationEarth Science and Technology (JAMSTEC), Japan #12;JIFT Workshop `Advanced Simulation Methods in Plasma Physics Methods in Plasma Physics'at NIFS, Dec.14-16 Introduction Virtual RealityVirtual Reality #12;JIFT Workshop

Ito, Atsushi

234

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

NASA Technical Reports Server (NTRS)

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.

Pepin, Gerard R.

1992-01-01

235

Simulating spin models on GPU  

E-print Network

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.

Martin Weigel

2010-06-19

236

Rule-based simulation models  

NASA Technical Reports Server (NTRS)

Procedural modeling systems, rule based modeling systems, and a method for converting a procedural model to a rule based model are described. Simulation models are used to represent real time engineering systems. A real time system can be represented by a set of equations or functions connected so that they perform in the same manner as the actual system. Most modeling system languages are based on FORTRAN or some other procedural language. Therefore, they must be enhanced with a reaction capability. Rule based systems are reactive by definition. Once the engineering system has been decomposed into a set of calculations using only basic algebraic unary operations, a knowledge network of calculations and functions can be constructed. The knowledge network required by a rule based system can be generated by a knowledge acquisition tool or a source level compiler. The compiler would take an existing model source file, a syntax template, and a symbol table and generate the knowledge network. Thus, existing procedural models can be translated and executed by a rule based system. Neural models can be provide the high capacity data manipulation required by the most complex real time models.

Nieten, Joseph L.; Seraphine, Kathleen M.

1991-01-01

237

Thermochemical modelling of advanced CANDU reactor fuel  

NASA Astrophysics Data System (ADS)

With an aging fleet of nuclear generating facilities, the imperative to limit the use of non-renewal fossil fuels and the inevitable need for additional electricity to power Canada's economy, a renaissance in the use of nuclear technology in Canada is at hand. The experience and knowledge of over 40 years of CANDU research, development and operation in Ontario and elsewhere has been applied to a new generation of CANDU, the Advanced CANDU Reactor (ACR). Improved fuel design allows for an extended burnup, which is a significant improvement, enhancing the safety and the economies of the ACR. The use of a Burnable Neutron Absorber (BNA) material and Low Enriched Uranium (LEU) fuel has created a need to understand better these novel materials and fuel types. This thesis documents a work to advance the scientific and technological knowledge of the ACR fuel design with respect to thermodynamic phase stability and fuel oxidation modelling. For the BNA material, a new (BNA) model is created based on the fundamental first principles of Gibbs energy minimization applied to material phase stability. For LEU fuel, the methodology used for the BNA model is applied to the oxidation of irradiated fuel. The pertinent knowledge base for uranium, oxygen and the major fission products is reviewed, updated and integrated to create a model that is applicable to current and future CANDU fuel designs. As part of this thesis, X-Ray Diffraction (XRD) and Coulombic Titration (CT) experiments are compared to the BNA and LEU models, respectively. From the analysis of the CT results, a number of improvements are proposed to enhance the LEU model and provide confidence in its application to ACR fuel. A number of applications for the potential use of these models are proposed and discussed. Keywords: CANDU Fuel, Gibbs Energy Mimimization, Low Enriched Uranium (LEU) Fuel, Burnable Neutron Absorber (BNA) Material, Coulometric Titration, X-Ray Diffraction

Corcoran, Emily Catherine

238

VISION: Verifiable Fuel Cycle Simulation Model  

SciTech Connect

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.

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

2009-04-01

239

VISION: Verifiable Fuel Cycle Simulation Model  

SciTech Connect

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.

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

2010-11-01

240

Time-domain analysis simulation for advanced tracking  

Microsoft Academic Search

TASAT is a complete end-to-end system simulation of tracking and pointing systems. It can currently model ground-based (GB), space-based (SB), and kinetic energy weapon (KEW) systems at a very high level of fidelity to assess system performance and design tradeoffs. It is primarily a time-domain analysis tool, but it can also perform frequency-domain analysis for performance and stability analysis. TASAT

Jim F. Riker; Gregg A. Crockett; Richard L. Brunson

1992-01-01

241

Simulation Model Development and Analysis in UNITY  

Microsoft Academic Search

We evaluate UNITY - a computational model, specification language and proof system defined by Chandy and Misra (5) for the development of parallel and distributed programs - as a platform for simulation model specification and analysis. We describe a UNITY-based methodology for the construction, analysis and execution of simulation models. The methodology starts with a simulation model specification in the

Ernest H. Page; Marc Abrams

2001-01-01

242

A simulation study of crew performance in operating an advanced transport aircraft in an automated terminal area environment  

NASA Technical Reports Server (NTRS)

A simulation study assessing crew performance operating an advanced transport aircraft in an automated terminal area environment is described. The linking together of the Langley Advanced Transport Operating Systems Aft Flight Deck Simulator with the Terminal Area Air Traffic Model Simulation was required. The realism of an air traffic control (ATC) environment with audio controller instructions for the flight crews and the capability of inserting a live aircraft into the terminal area model to interact with computer generated aircraft was provided. Crew performance using the advanced displays and two separate control systems (automatic and manual) in flying area navigation routes in the automated ATC environment was assessed. Although the crews did not perform as well using the manual control system, their performances were within acceptable operational limits with little increase in workload. The crews favored using the manual control system and felt they were more alert and aware of their environment when using it.

Houck, J. A.

1983-01-01

243

Mathematical modeling and SAR simulation multifunction SAR technology efforts  

NASA Technical Reports Server (NTRS)

The orbital SAR (synthetic aperture radar) simulation data was used in several simulation efforts directed toward advanced SAR development. Efforts toward simulating an operational radar, simulation of antenna polarization effects, and simulation of SAR images at serveral different wavelengths are discussed. Avenues for improvements in the orbital SAR simulation and its application to the development of advanced digital radar data processing schemes are indicated.

Griffin, C. R.; Estes, J. M.

1981-01-01

244

Advanced Modelling of Silicon Wafer Solar Cells  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

245

Quality assurance paradigms for artificial intelligence in modelling and simulation  

SciTech Connect

New classes of quality assurance concepts and techniques are required for the advanced knowledge-processing paradigms (such as artificial intelligence, expert systems, or knowledge-based systems) and the complex problems that only simulative systems can cope with. A systematization of quality assurance problems as well as examples are given to traditional and cognizant quality assurance techniques in traditional and cognizant modelling and simulation.

Oren, T.I.

1987-04-01

246

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

PubMed Central

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.

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

2014-01-01

247

Mathematical Modeling of a Simulated Fixed Bed for Desalting Operation  

Microsoft Academic Search

Continue survival of the petrochemical industry in the face of advancement in processing technology must change for better performance. In doing so, the pre-treatment stage of crude, which include desalting will go a long way at improving the overall quality of the product obtained. It is in view of this that a mathematical modeling of adsorption of a fixed simulated

MOHAMMED ALHASSAN; M. A. OLUTOYE

248

OXYGEN UTILIZATION IN ACTIVATED SLUDGE PLANTS: SIMULATION AND MODEL CALIBRATION  

EPA Science Inventory

The objective of the research described in the report is to apply recent advances in activated sludge process modeling to the simulation of oxygen utilization rates in full scale activated sludge treatment plants. This is accomplished by calibrating the International Association ...

249

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

250

Towards Grid-Wide Modeling and Simulation  

E-print Network

Modeling and simulation permeate all areas of business, science and engineering. With the increase in the scale and complexity of simulations, large amounts of computational resources are required, and collaborative model ...

Xie, Yong

251

Crashworthiness analysis using advanced material models in DYNA3D  

SciTech Connect

As part of an electric vehicle consortium, LLNL and Kaiser Aluminum are conducting experimental and numerical studies on crashworthy aluminum spaceframe designs. They have jointly explored the effect of heat treat on crush behavior and duplicated the experimental behavior with finite-element simulations. The major technical contributions to the state of the art in numerical simulation arise from the development and use of advanced material model descriptions for LLNL`s DYNA3D code. Constitutive model enhancements in both flow and failure have been employed for conventional materials such as low-carbon steels, and also for lighter weight materials such as aluminum and fiber composites being considered for future vehicles. The constitutive model enhancements are developed as extensions from LLNL`s work in anisotropic flow and multiaxial failure modeling. Analysis quality as a function of level of simplification of material behavior and mesh is explored, as well as the penalty in computation cost that must be paid for using more complex models and meshes. The lightweight material modeling technology is being used at the vehicle component level to explore the safety implications of small neighborhood electric vehicles manufactured almost exclusively from these materials.

Logan, R.W.; Burger, M.J.; McMichael, L.D. [Lawrence Livermore National Lab., CA (United States); Parkinson, R.D. [Kaiser Aluminum & Chemical Corp., Pleasanton, CA (United States). Center for Technology

1993-10-22

252

Advancing an Information Model for Environmental Observations  

NASA Astrophysics Data System (ADS)

Observational data are fundamental to hydrology and water resources, and the way they are organized, described, and shared either enables or inhibits the analyses that can be performed using the data. The CUAHSI Hydrologic Information System (HIS) project is developing cyberinfrastructure to support hydrologic science by enabling better access to hydrologic data. HIS is composed of three major components. HydroServer is a software stack for publishing time series of hydrologic observations on the Internet as well as geospatial data using standards-based web feature, map, and coverage services. HydroCatalog is a centralized facility that catalogs the data contents of individual HydroServers and enables search across them. HydroDesktop is a client application that interacts with both HydroServer and HydroCatalog to discover, download, visualize, and analyze hydrologic observations published on one or more HydroServers. All three components of HIS are founded upon an information model for hydrologic observations at stationary points that specifies the entities, relationships, constraints, rules, and semantics of the observational data and that supports its data services. Within this information model, observations are described with ancillary information (metadata) about the observations to allow them to be unambiguously interpreted and used, and to provide traceable heritage from raw measurements to useable information. Physical implementations of this information model include the Observations Data Model (ODM) for storing hydrologic observations, Water Markup Language (WaterML) for encoding observations for transmittal over the Internet, the HydroCatalog metadata catalog database, and the HydroDesktop data cache database. The CUAHSI HIS and this information model have now been in use for several years, and have been deployed across many different academic institutions as well as across several national agency data repositories. Additionally, components of the HIS have been modified to support data management for the Critical Zone Observatories (CZOs). This paper will present limitations of the existing information model used by the CUAHSI HIS that have been uncovered through its deployment and use, as well as new advances to the information model, including: better representation of both in situ observations from field sensors and observations derived from environmental samples, extensibility in attributes used to describe observations, and observation provenance. These advances have been developed by the HIS team and the broader scientific community and will enable the information model to accommodate and better describe wider classes of environmental observations and to better meet the needs of the hydrologic science and CZO communities.

Horsburgh, J. S.; Aufdenkampe, A. K.; Hooper, R. P.; Lehnert, K. A.; Schreuders, K.; Tarboton, D. G.; Valentine, D. W.; Zaslavsky, I.

2011-12-01

253

Advanced Power Plant Modeling with Applications to an Advanced Boiling Water  

E-print Network

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, or two-phase flow with boiling; and with the lateral addition of heat from the wall directly or through

Mitchell, John E.

254

Operations planning simulation: Model study  

NASA Technical Reports Server (NTRS)

The use of simulation modeling for the identification of system sensitivities to internal and external forces and variables is discussed. The technique provides a means of exploring alternate system procedures and processes, so that these alternatives may be considered on a mutually comparative basis permitting the selection of a mode or modes of operation which have potential advantages to the system user and the operator. These advantages are measurements is system efficiency are: (1) the ability to meet specific schedules for operations, mission or mission readiness requirements or performance standards and (2) to accomplish the objectives within cost effective limits.

1974-01-01

255

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect

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.

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

2006-06-18

256

Advanced thermal energy management: A thermal test bed and heat pipe simulation  

NASA Astrophysics Data System (ADS)

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Barile, Ronald G.

1986-11-01

257

Advanced thermal energy management: A thermal test bed and heat pipe simulation  

NASA Technical Reports Server (NTRS)

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Barile, Ronald G.

1986-01-01

258

A Social Diffusion Model with an Application on Election Simulation  

PubMed Central

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

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

2014-01-01

259

Development of a GOES-R Advanced Baseline Imager Solar Channel Radiance Simulator for Ice Clouds  

E-print Network

Development of a GOES-R Advanced Baseline Imager Solar Channel Radiance Simulator for Ice Clouds Satellite R (GOES-R) Advanced Baseline Imager (ABI) solar channels. The simulator is based on the discrete single-scattering property database of both smooth and severely roughened ice particles, which include

Baum, Bryan A.

260

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

Microsoft Academic Search

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.

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

1999-01-01

261

Advances in HTGR fuel performance models  

SciTech Connect

Fuel performance models based on empirical evidence are used to predict particle failure and fission product release in the design of high-temperature gas-cooled reactors (HTGRs). Advances in HTGR fuel performance models have improved the agreement between observed and predicted performance and contributed to an enhanced position of the HTGR with regard to investment risk and passive safety. Heavy metal contamination is the source of about 55% of the circulating activity in the HTGR during normal operation, and the remainder comes primarily from particles which failed because of defective or missing buffer coatings. These failed particles make up about 5 x 10/sup -4/ fraction of the total core inventory. In addition to prediction of fuel performance during normal operation, the models are used to determine fuel failure and fission product release during core heat-up accident conditions. The mechanistic nature of the models, which incorporate all important failure modes, permits the prediction of performance from the relatively modest accident temperatures of a passively safe HTGR to the much more severe accident conditions of the larger 2240-MW(t) HTGR.

Stansfield, O.M.; Goodin, D.T.; Hanson, D.L.; Turner, R.F.

1985-02-01

262

Detailed simulation of morphodynamics: 1. Hydrodynamic model  

NASA Astrophysics Data System (ADS)

We present a three-dimensional high-resolution hydrodynamic model for unsteady incompressible flow over an evolving bed topography. This is achieved by using a multilevel Cartesian grid technique that allows the grid to be refined in high-gradient regions and in the vicinity of the river bed. The grid can be locally refined and adapted to the bed geometry, managing the Cartesian grid cells and faces using a hierarchical tree data approach. A ghost-cell immersed-boundary technique is applied to cells intersecting the bed topography. The governing equations have been discretized using a finite-volume method on a staggered grid, conserving second-order accuracy in time and space. The solution advances in time using the fractional step approach. Large-eddy simulation is used as turbulence closure. We validate the model against several experiments and other results from literature. Model results for Stokes flow around a cylinder in the vicinity of a moving wall agree well with Wannier's analytical solution. At higher Reynolds numbers, computed trailing bubble length, separation angle, and drag coefficient compare favorably with experimental and previous computational results. Results for the flow over two- and three-dimensional dunes agree well with published data, including a fair reproduction of recirculation zones, horse-shoe structures, and boiling effects. This shows that the model is suitable for being used as a hydrodynamic submodel in the high-resolution modeling of sediment transport and formation and evolution of subaqueous ripples and dunes.

Nabi, M.; de Vriend, H. J.; Mosselman, E.; Sloff, C. J.; Shimizu, Y.

2012-12-01

263

A modular BLSS simulation model  

NASA Technical Reports Server (NTRS)

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.

Rummel, John D.; Volk, Tyler

1987-01-01

264

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

NASA Technical Reports Server (NTRS)

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'.

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

2014-01-01

265

Advanced wellbore thermal simulator GEOTEMP2 user manual  

SciTech Connect

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.

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

1984-11-01

266

Knowledge, Models and Tools in Support of Advanced Distance Learning.  

National Technical Information Service (NTIS)

This report describes research conducted by the University of Southern California Behavioral Technology Laboratory in developing iRides, an advanced system for delivering authored interactive graphical simulations and instructional vignettes. The system p...

A. Munro, Q. A. Pizzini, M. C. Johnson, J. Walker, D. Surmon

2006-01-01

267

Advanced co-simulation for computer-aided process design and optimization of fossil energy systems with carbon capture  

SciTech Connect

In this paper, we describe recent progress toward developing an Advanced Process Engineering Co-Simulator (APECS) for use in computer-aided design and optimization of fossil energy systems with carbon capture. The APECS system combines process simulation with multiphysicsbased equipment simulations, such as those based on computational fluid dynamics. These co-simulation capabilities enable design engineers to optimize overall process performance with respect to complex thermal and fluid flow phenomena arising in key plant equipment items. This paper also highlights ongoing co-simulation R&D activities in areas such as reduced order modeling, knowledge management, stochastic analysis and optimization, and virtual plant co-simulation. Continued progress in co-simulation technology— through improved integration, solution, deployment, and analysis —will have profound positive impacts on the design and optimization of high-efficiency, near-zero emission fossil energy systems.

Zitney, S.

2009-01-01

268

USER'S GUIDE FOR THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL  

EPA Science Inventory

The Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model simulates long-range, long-term transport and deposition of air pollutants, primarily oxides of sulfur and nitrogen. The ASTRAP model is designed to combine ease of exercise with an appropriate detail of ph...

269

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

Microsoft Academic Search

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,

Florence Vanel Hutcheson

1999-01-01

270

Project ENDEAVOR: distributed modeling for advanced marine vehicle performance analysis  

Microsoft Academic Search

Project ENDEAVOR (Booij et al., 1999) (Environment for Design of Advanced Marine Vehicles and Operations Research) has devised a unique capability to support advanced marine vehicles (AMVs) in the areas of mission planning, design, and performance analysis. The Project has established an 8-year global NOAA WaveWatch III (WWIII) deepwater condition database to feed the Simulation of Waves Nearshore (SWAN)2 regional

Donald Fabozzi; J. Bergquist; John Winship; Demont Hansen

2005-01-01

271

Special purpose simulation modeling of tower cranes  

Microsoft Academic Search

Historically, simulation tools have only been used and understood by the academic community. Special purpose simulation (SPS) techniques have introduced computer modeling to the industry, resulting in reduced model development time and a user-friendly environment. This paper describes the special purpose simulation template, which is based on the tower crane operations performed by PCL Constructors Incorporated. On-site management of the

Bradford J. A. Appleton; J. Patra; Y. Mohamed; S. AbourRizk

2002-01-01

272

Verification and validation of simulation models  

Microsoft Academic Search

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,

Jack P. C. Kleijnen

1995-01-01

273

Modeling and simulation of power electronic converters  

Microsoft Academic Search

This paper reviews some of the major approaches to modeling and simulation in power electronics, and provides references that can serve as a starting point for the extensive literature on the subject. The major focus of the paper is on averaged models of various kinds, but sampled-data models are also introduced. The importance of hierarchical modeling and simulation is emphasized

DRAGAN MAKSIMOVIC ´; ALEKSANDAR M. STANKOVIC; V. JOSEPH THOTTUVELIL; GEORGE C. VERGHESE

2001-01-01

274

Validation and verification of simulation models  

Microsoft Academic Search

ABSTRACT This paper discusses validation and verification of simulation models. The different approaches to deciding model validity are presented; how,model validation and verification 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; and a recommended,procedure is presented. 1,INTRODUCTION Simulation models are increasingly

Robert G. Sargent

1992-01-01

275

Generation of large scale urban environments to support advanced sensor and seeker simulation  

NASA Astrophysics Data System (ADS)

One of the key aspects for the design of a next generation weapon system is the need to operate in cluttered and complex urban environments. Simulation systems rely on accurate representation of these environments and require automated software tools to construct the underlying 3D geometry and associated spectral and material properties that are then formatted for various objective seeker simulation systems. Under an Air Force Small Business Innovative Research (SBIR) contract, we have developed an automated process to generate 3D urban environments with user defined properties. These environments can be composed from a wide variety of source materials, including vector source data, pre-existing 3D models, and digital elevation models, and rapidly organized into a geo-specific visual simulation database. This intermediate representation can be easily inspected in the visible spectrum for content and organization and interactively queried for accuracy. Once the database contains the required contents, it can then be exported into specific synthetic scene generation runtime formats, preserving the relationship between geometry and material properties. To date an exporter for the Irma simulation system developed and maintained by AFRL/Eglin has been created and a second exporter to Real Time Composite Hardbody and Missile Plume (CHAMP) simulation system for real-time use is currently being developed. This process supports significantly more complex target environments than previous approaches to database generation. In this paper we describe the capabilities for content creation for advanced seeker processing algorithms simulation and sensor stimulation, including the overall database compilation process and sample databases produced and exported for the Irma runtime system. We also discuss the addition of object dynamics and viewer dynamics within the visual simulation into the Irma runtime environment.

Giuliani, Joseph; Hershey, Daniel; McKeown, David, Jr.; Willis, Carla; Van, Tan

2009-05-01

276

Off-gas Adsorption Model and Simulation - OSPREY  

SciTech Connect

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.

Veronica J Rutledge

2013-10-01

277

RECENT ADVANCES IN MACROMOLECULAR HYDRODYNAMIC MODELING  

PubMed Central

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

Aragon, Sergio R.

2010-01-01

278

Advances in Multiscale Simulations of Solar Wind Interactions with the Earth's Magnetosphere  

NASA Astrophysics Data System (ADS)

The accuracy of space weather forecasts critically depends on the availability of realistic models of the near-Earth environment driven by the solar wind. With advances in computer technology and numerical algorithms it has recently become possible to model strongly kinetic parts of the outer magnetosphere with hybrid and particle-in-cell codes. The critical issue in global simulations is efficient handling of disparate temporal and spatial scales. In conventional hybrid simulations the global time step has to be severely reduced in order to properly account for energetic/fast gyrating particles and fast whistler oscillations in high magnetic field/low density regions. Recently we introduced and validated a novel asynchronous, discrete-event hybrid code that resolves these issues: HYPERS. Here we report recent improvements to HYPERS and demonstrate its new capabilities by conducting simulations of the interaction of high-Mach solar wind flows with the Earth's magnetosphere formed for a nearly radial interplanetary magnetic field. We show that discrete-event simulations are capable of asynchronously resolving times scales differing by orders of magnitude.

Omelchenko, Y. A.; Karimabadi, H.; Vu, H. X.

2014-09-01

279

Advanced Method to Estimate Fuel Slosh Simulation Parameters  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

280

Design Tradeoffs in the Development of the Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) HWIL Facilities  

Microsoft Academic Search

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

Kenneth G. LeSueur; Frank J. Almendinger

281

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

Microsoft Academic Search

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

Kenneth G. LeSueur; Frank J. Almendinger

2007-01-01

282

Simulation based Bayesian econometric inference: principles and some recent computational advances  

E-print Network

2007/15 Simulation based Bayesian econometric inference: principles and some recent computational/15 Simulation based Bayesian econometric inference: principles and some recent computational advances Lennart F aspects of simulation based Bayesian econometric inference. We start at an elementary level on basic

Nesterov, Yurii

283

Monte Carlo simulations to advance characterisation of landmines by pulsed fast\\/thermal neutron analysis  

Microsoft Academic Search

The performance of a detection system based on the pulsed fast\\/thermal neutron analysis technique was assessed using Monte Carlo simulations. The aim was to develop and implement simulation methods, to support and advance the data analysis techniques of the characteristic ?-ray spectra, potentially leading to elemental characterisation of innocuous objects using the full spectrum analysis (FSA) approach. The simulations were

C. Rigollet

2004-01-01

284

Aeroacoustic simulation for phonation modeling  

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

285

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

SciTech Connect

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.

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

2011-01-01

286

An introduction to enterprise modeling and simulation  

SciTech Connect

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.

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

1996-09-01

287

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

SciTech Connect

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.

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

288

Sensitivity of an ecological model to soil moisture simulations from two different hydrological models  

Microsoft Academic Search

Summary  Although advanced land surface schemes have been developed in the past decade, many biosphere models still use the simple\\u000a bucket model, partly due to its efficiency when it is coupled with an CGCM model. In this paper, we use a sophisticated land\\u000a surface model, the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS), including an explicit vegetation

D. Ren; L. M. Leslie; D. J. Karoly

2008-01-01

289

Verification and Validation of Simulation Model  

E-print Network

Verification and Validation of Simulation Model 1 Verification and Validation 2 #12;Verification · Examples ­ simulation model: open networks with exponential interarrival time distribution and uniform is consistent with known analytic results 5 Validation · Model should be "good enough" (subjective) · Seek

Shihada, Basem

290

COMPOSABLE SIMULATION MODELS AND THEIR FORMAL VALIDATION  

E-print Network

COMPOSABLE SIMULATION MODELS AND THEIR FORMAL VALIDATION CLAUDIA SZABO B. Eng., "POLITEHNICA, as well as the verification and validation of the composed model. Using a component- connector paradigm and simulation, shared models are reused and as- sembled in various combinations to meet different user

Teo, Yong-Meng

291

Investment simulation model in electrical utility industry  

SciTech Connect

A simulation model is presented which would provide an effective investment tool with the decision makers in dealing with uncertainty inherent in the choice of constructing a power plant. A general simulation model based upon SLAM is developed and a case study is provided to demonstrate the effectiveness of the model. 2 refs.

Park, C.S.

1980-01-01

292

Advanced Neutron Source Dynamic Model (ANSDM) code description and user guide  

SciTech Connect

A mathematical model is designed that simulates the dynamic behavior of the Advanced Neutron Source (ANS) reactor. Its main objective is to model important characteristics of the ANS systems as they are being designed, updated, and employed; its primary design goal, to aid in the development of safety and control features. During the simulations the model is also found to aid in making design decisions for thermal-hydraulic systems. Model components, empirical correlations, and model parameters are discussed; sample procedures are also given. Modifications are cited, and significant development and application efforts are noted focusing on examination of instrumentation required during and after accidents to ensure adequate monitoring during transient conditions.

March-Leuba, J.

1995-08-01

293

RAM simulation model for SPH/RSV systems  

SciTech Connect

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.

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

1995-12-31

294

Software Platform Evaluation - Verifiable Fuel Cycle Simulation (VISION) Model  

SciTech Connect

The purpose of this Software Platform Evaluation (SPE) is to document the top-level evaluation of potential software platforms on which to construct a simulation model that satisfies the requirements for a Verifiable Fuel Cycle Simulation Model (VISION) of the Advanced Fuel Cycle (AFC). See the Software Requirements Specification for Verifiable Fuel Cycle Simulation (VISION) Model (INEEL/EXT-05-02643, Rev. 0) for a discussion of the objective and scope of the VISION model. VISION is intended to serve as 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. This document will serve as a guide for selecting the most appropriate software platform for VISION. This is a “living document” that will be modified over the course of the execution of this work.

J. J. Jacobson; D. E. Shropshire; W. B. West

2005-11-01

295

Verification, validation and accreditation of simulation models  

Microsoft Academic Search

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;

Robert G. Sargent

2000-01-01

296

Validation and verification of simulation models  

Microsoft Academic Search

This paper discusses validation and verification of simulation models. The different approaches to deciding model validity are presented; how model validation and verification 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; and a recommended procedure is presented.

Robert G. Sargent

1999-01-01

297

Verification and validation of simulation models  

Microsoft Academic Search

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

Robert G. Sargent

1994-01-01

298

Validation and verification of simulation models  

Microsoft Academic Search

This paper discusses validation and verification of simulation models. The different approaches to deciding model validity are presented; how model validation and verification 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; and a recommended procedure is presented

Robert G. Sargent

1999-01-01

299

Improving the aircraft design process using Web-based modeling and simulation  

Microsoft Academic Search

Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed

John A. Reed; Gregory J. Follen; Abdollah A. Afjeh

2000-01-01

300

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

E-print Network

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 ...

Florian, Daniel George

2004-01-01

301

Theory, Modeling, and Simulation of Semiconductor Lasers  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

302

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

SciTech Connect

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).

R. A. Berry

2010-11-01

303

Modeling, Simulation and Analysis of Public Key Infrastructure  

NASA Technical Reports Server (NTRS)

Security is an essential part of network communication. The advances in cryptography have provided solutions to many of the network security requirements. Public Key Infrastructure (PKI) is the foundation of the cryptography applications. The main objective of this research is to design a model to simulate a reliable, scalable, manageable, and high-performance public key infrastructure. We build a model to simulate the NASA public key infrastructure by using SimProcess and MatLab Software. The simulation is from top level all the way down to the computation needed for encryption, decryption, digital signature, and secure web server. The application of secure web server could be utilized in wireless communications. The results of the simulation are analyzed and confirmed by using queueing theory.

Liu, Yuan-Kwei; Tuey, Richard; Ma, Paul (Technical Monitor)

1998-01-01

304

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

305

Advanced model-based control for continuous process industries  

Microsoft Academic Search

Advanced control is an economical method to maximize return on existing capital investment in plants while minimizing the production. The challenge is to also minimize the cost of the material and human resources needed to implement advanced control on real world applications. This paper describes an innovative adaptive process controller based on an unstructured process modeling technique called dynamic modeling

Bill Gough; Bruce Wilson; Don Matovich

1998-01-01

306

Simulation of an advanced negative i-line photoresist  

NASA Astrophysics Data System (ADS)

A new i-line negative resist has been developed which exploits acid-catalyzed cross-linking chemistry in combination with a sensitizing chromophore and a light absorbing dye. During exposure acid is generated by excitation energy transfer from the sensitizer to a halogen- containing compound. Concurrently, the highly absorbing dye is bleached. The optical component of this resist can be modeled as follows: the imaginary part of the complex refractive index is proportional to A1M1 + A2M2 + B, where M1 is the bleachable dye concentration, M2 is the sensitizer concentration, B is the fixed absorption and A1 and A2 are the corresponding Dill coefficients for bleachable absorbance. The kinetics of the bleachable dye and sensitizer decays are given by (delta) Mi/(delta) t equals -CiMiI. The final acid concentration is a nonlinear function of these concentrations and can be expressed as H equals [(1-M2) + (kappa) (1-M1)]/(1 + (kappa) ) with (kappa) determined experimentally. The exposure is computed by our spectral element numerical method. As exposure terminates, post exposure baking (PEB) takes place, similar in form to the crosslinking of the deep-UV product MegapositR SNRTM 248 Series photoresist. This step is modeled via reaction diffusion equations, producing a nonsoluble monolith due to cross-linking of the polymers. The final profiles are obtained by solution of a system of reaction-diffusion equations and are described graphically using a novel dynamic triangulation algorithm. A comparison between simulated and actual micrographs is given and process latitude and CD control discussed.

Barouch, Eytan; Hollerbach, Uwe; Orszag, Steven A.; Allen, Mary T.; Calabrese, Gary S.

1991-07-01

307

Advanced numerical methods and software approaches for semiconductor device simulation  

SciTech Connect

In this article the authors concisely present several modern strategies that are applicable to drift-dominated carrier transport in higher-order deterministic models such as the drift-diffusion, 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 the methods have been applied to the semiconductor device problem while others are still in the early stages of development for this class of applications. They have included numerical examples from the 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 they emphasize the need for further work on analysis, data structures and software to support adaptivity. Finally, they 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.

CAREY,GRAHAM F.; PARDHANANI,A.L.; BOVA,STEVEN W.

2000-03-23

308

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

309

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

NASA Technical Reports Server (NTRS)

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.

Carroll, Chester C.; Owen, Jeffrey E.

1988-01-01

310

Advanced Lagrangian simulation algorithms for magnetized plasma turbulence  

Microsoft Academic Search

Nonlinear processes in hot, magnetized plasma are notoriously difficult to understand without the use of numerical simulations. In recent decades, first principles, kinetic simulations have been widely and successfully used to study plasma turbulence and reconnection in weakly collisional systems. In this thesis, extensions of well-known, Lagrangian, particle-in-cell (PIC) simulation algorithms for problems such as these are derived and implemented.

Ingmar Bert Broemstrup

2008-01-01

311

Advanced tokamak research with integrated modeling in JT-60 Upgradea)  

NASA Astrophysics Data System (ADS)

Researches on advanced tokamak (AT) have progressed with integrated modeling in JT-60 Upgrade [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)]. Based on JT-60U experimental analyses and first principle simulations, new models were developed and integrated into core, rotation, edge/pedestal, and scrape-off-layer (SOL)/divertor codes. The integrated models clarified complex and autonomous features in AT. An integrated core model was implemented to take account of an anomalous radial transport of alpha particles caused by Alfven eigenmodes. It showed the reduction in the fusion gain by the anomalous radial transport and further escape of alpha particles. Integrated rotation model showed mechanisms of rotation driven by the magnetic-field-ripple loss of fast ions and the charge separation due to fast-ion drift. An inward pinch model of high-Z impurity due to the atomic process was developed and indicated that the pinch velocity increases with the toroidal rotation. Integrated edge/pedestal model clarified causes of collisionality dependence of energy loss due to the edge localized mode and the enhancement of energy loss by steepening a core pressure gradient just inside the pedestal top. An ideal magnetohydrodynamics stability code was developed to take account of toroidal rotation and clarified a destabilizing effect of rotation on the pedestal. Integrated SOL/divertor model clarified a mechanism of X-point multifaceted asymmetric radiation from edge. A model of the SOL flow driven by core particle orbits which partially enter the SOL was developed by introducing the ion-orbit-induced flow to fluid equations.

Hayashi, N.; JT-60 Team

2010-05-01

312

A Generic Multibody Parachute Simulation Model  

NASA Technical Reports Server (NTRS)

Flight simulation of dynamic atmospheric vehicles with parachute systems is a complex task that is not easily modeled in many simulation frameworks. In the past, the performance of vehicles with parachutes was analyzed by simulations dedicated to parachute operations and were generally not used for any other portion of the vehicle flight trajectory. This approach required multiple simulation resources to completely analyze the performance of the vehicle. Recently, improved software engineering practices and increased computational power have allowed a single simulation to model the entire flight profile of a vehicle employing a parachute.

Neuhaus, Jason Richard; Kenney, Patrick Sean

2006-01-01

313

Chemical Models of Advanced Oxidation Processes.  

National Technical Information Service (NTIS)

Advanced oxidation processes (AOPs) have been defined as ambient temperature processes which involve the generation of highly reactive oxyradicals, especially the hydroxyl radical. These processes show promise for the destruction of hazardous organic subs...

W. H. Glaze

1991-01-01

314

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect

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.

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

2006-06-22

315

Advanced techniques and painless procedures for nonlinear contact analysis and forming simulation via implicit FEM  

NASA Astrophysics Data System (ADS)

Nonlinear contact analysis including forming simulation via finite element methods has a crucial and practical application in many engineering fields. However, because of high nonlinearity, nonlinear contact analysis still remains as an extremely challenging obstacle for many industrial applications. The implicit finite element scheme is generally more accurate than the explicit finite element scheme, but it has a known challenge of convergence because of complex geometries, large relative motion and rapid contact state change. It might be thought as a very painful process to diagnose the convergence issue of nonlinear contact. Most complicated contact models have a great many contact surfaces, and it is hard work to well define the contact pairs using the common contact definition methods, which either result in hundreds of contact pairs or are time-consuming. This paper presents the advanced techniques of nonlinear contact analysis and forming simulation via the implicit finite element scheme and the penalty method. The calculation of the default automatic contact stiffness is addressed. Furthermore, this paper presents the idea of selection groups to help easily and efficiently define contact pairs for complicated contact analysis, and the corresponding implementation and usage are discussed. Lastly, typical nonlinear contact models and forming models with nonlinear material models are shown in the paper to demonstrate the key presented method and technologies.

Zhuang, Shoubing

2013-05-01

316

Model validation with hybrid dynamic simulation  

Microsoft Academic Search

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

Zhenyu Huang; M. Kosterev; Ross T. Guttromson; Tony B. Nguyen

2006-01-01

317

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described, a graphical paradigm that relates verification and validation to the model development process is presented, and various validation techniques are defined. Conceptual model validity, model verification, operational validity, and data validity are discussed and a way to document results is

Robert G. Sargent

2011-01-01

318

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2010-01-01

319

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2005-01-01

320

Validation and Verification of Simulation Models  

Microsoft Academic Search

In this paper we discuss validation and verification of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate validation and verification to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2004-01-01

321

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2007-01-01

322

Verification and validation of simulation models  

Microsoft Academic Search

In this paper we discuss verification and validation of simulation models. Four different approaches to deciding model validity are described; two different paradigms that relate verification and validation to the model development process are presented; various validation techniques are defined; conceptual model validity, model verification, operational validity, and data validity are discussed; a way to document results is given; a

Robert G. Sargent

2003-01-01

323

Computational Modeling and Simulation of Infectious Diseases  

E-print Network

Computational Modeling and Simulation of Infectious Diseases May 21­July 27, 2012 Receive a 10-week of Public Health Models of Infectious Disease Agent Study (MIDAS) National Center of Excellence #12;

Sibille, Etienne

324

VHDL simulation with access to transistor models  

NASA Technical Reports Server (NTRS)

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.

Gibson, J.

1991-01-01

325

Advanced process and device modeling of full-frame CCD imagers (Invited Paper)  

Microsoft Academic Search

Using Synopsys TCAD tools, several examples of advanced process and device modeling are presented for full-frame CCD image sensors. The topics covered in these examples include channel potential, charge capacity, charge transport, and charge blooming. The simulations provide in depth analysis of the basic principles of operation of CCDs and cover some aspects of antiblooming protection.

Carl J. Wordelman; Edmund K. Banghart

2005-01-01

326

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

NASA Astrophysics Data System (ADS)

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.

Zhou, L. X.

2013-07-01

327

Fast Simulation of Facilitated Spin Models  

NASA Astrophysics Data System (ADS)

We show how to apply the absorbing Markov chain Monte Carlo algorithm of Novotny to simulate kinetically constrained models of glasses. In detail we consider the East model in one dimension. We investigate how to maximize the efficiency of the algorithms, and show that simulation times can be improved on standard continuous time Monte Carlo by several orders of magnitude. We discuss how the method can be applied to other kinetically constrained models with specific focus on the 2-spin facilitated FA model.

Ashton, D. J.; Hedges, L. O.; Garrahan, J. P.

2006-05-01

328

Empirical analysis in software process simulation modeling  

Microsoft Academic Search

Software process simulation modeling is increasingly being used to address a variety of issues from the strategic management of software development, to supporting process improvements, to software project management training. The scope of software process simulation applications ranges from narrow focused portions of the life cycle to longer-term product evolutionary models with broad organizational impacts. This paper discusses some of

David M. Raffo; Marc I. Kellner

2000-01-01

329

Computer simulations and physical modelling of erosion  

E-print Network

particle hydrodynamics (SPH). Navier-Stokes on voxel grid. · Terrain development: layered height field · initial SPH model and simulations · visit to Brazil 9 / 10 #12;Future · multiple layers of soil. · sandComputer simulations and physical modelling of erosion C.S. Stuetzle, J. Gross, Z. Chen, B. Cutler

Franklin, W. Randolph

330

Monte Carlo Simulation of Interacting Electron Models  

E-print Network

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

Robinson, Robert W.

331

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

SciTech Connect

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.

Seitz, R.

2013-02-26

332

Modeling and simulation of friction  

Microsoft Academic Search

Two new models for 'slip-stick' friction are presented. One, called the 'bristle model,' is an approximation designed to capture the physical phenomenon of sticking. This model is relatively inefficient numerically. The other model, called the 'reset integrator model,' does not capture the details for the sticking phenomenon, but is numerically efficient and exhibits behavior similar to the model proposed by

David A. Haessig; Bernard Friedland

1991-01-01

333

Micromagnetic modeling simulations and applications  

Microsoft Academic Search

The advancement in micro and nano-scale technologies demands in depth understanding of magnetic behaviors. For example, as the ever increasing need for high capacity data storage continuously pushes the boundaries of magnetic recording technology to the physical limits, detailed analysis of the magnetic properties becomes necessary. It is expected that finite element micromagnetics can predict the magnetic behavior with high

H. H. Long; Z. J. Liu; E. T. Ong; E. P. Li

2006-01-01

334

Modeling and simulation of reactive distillation operations  

SciTech Connect

Important aspects related to modeling and simulation of reactive distillation processes are presented. Reactive distillation processes are system specific and are subject to the sensitivity of the model parameters. The sensitive model parameters have been identified as those belonging to the models describing the physical and/or chemical equilibrium of the reactive system. The influence of the sensitive model parameters on simulation/design is highlighted through a systematic analysis of the models typically employed for steady-state and dynamic simulation of reactive distillation operations. For reliable and consistent simulation and design of reactive distillation operations, a necessary first step is a systematic analysis of the model parameter and the design/operational variables. Validated numerical results from test problems involving two reactive systems are presented.

Pilavachi, P.A. [Univ. Libre de Bruxelles, Brussels (Belgium). Faculty of Applied Sciences] [Univ. Libre de Bruxelles, Brussels (Belgium). Faculty of Applied Sciences; Schenk, M.; Perez-Cisneros, E.; Gani, R. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering] [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

1997-08-01

335

Institute for Advanced Simulation Large Spatiotemporal-Scale Material  

E-print Network

metal-oxygen flip mechanism at the metal/oxide interface in thermites; (2) a crossover of oxidation.14 million atoms for T = 1 microseconds). Results of multimillion-atom reactive MD simulations on nano

Southern California, University of

336

New Developments in the Simulation of Advanced Accelerator Concepts  

E-print Network

from intense laser–plasma interactions,” Nature 431, 535 (laser-plasma simulations, making them practical in 3D for interactionlaser wavelength wavelength) increases by b (1+ b ) and the interaction time (like the plasma

Bruhwiler, D.L.

2010-01-01

337

Developments in Atmosphere Revitalization Modeling and Simulation  

NASA Technical Reports Server (NTRS)

"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.

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

2012-01-01

338

Simulation model of a twin-tail, high performance airplane  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

339

Psychometric and Evidentiary Advances, Opportunities, and Challenges for Simulation-Based Assessment  

ERIC Educational Resources Information Center

This article characterizes the advances, opportunities, and challenges for psychometrics of simulation-based assessments through a lens that views assessment as evidentiary reasoning. Simulation-based tasks offer the prospect for student experiences that differ from traditional assessment. Such tasks may be used to support evidentiary arguments…

Levy, Roy

2013-01-01

340

The Advancement Value Chain: An Exploratory Model  

ERIC Educational Resources Information Center

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…

Leonard, Edward F., III

2005-01-01

341

Predicting Career Advancement with Structural Equation Modelling  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to use the authors' prior findings concerning basic employability skills in order to determine which skills best predict career advancement potential. Design/methodology/approach: Utilizing survey responses of human resource managers, the employability skills showing the largest relationships to career…

Heimler, Ronald; Rosenberg, Stuart; Morote, Elsa-Sofia

2012-01-01

342

Advanced Computer Simulations Of Nanomaterials And Stochastic Biological Processes  

NASA Astrophysics Data System (ADS)

This dissertation consists of several parts. The first two chapters are devoted to of study of dynamic processes in cellular organelles called filopodia. A stochastic kinetics approach is used to describe non-equilibrium evolution of the filopodial system from nano- to micro scales. Dynamic coupling between chemistry and mechanics is also taken into account in order to investigate the influence of focal adhesions on cell motility. The second chapter explores the possibilities and effects of motor enhanced delivery of actin monomers to the polymerizing tips of filopodia, and how the steady-state filopodial length can exceed the limit set by pure diffusion. Finally, we also challenge the currently existing view of active transport and propose a new theoretical model that accurately describes the motor dynamics and concentration profiles seen in experiments in a physically meaningful way. The third chapter is a result of collaboration between three laboratories, as a part of Energy Frontier Research Center at the University of North Carolina at Chapel Hill. The work presented here unified the fields of synthetic chemistry, photochemistry, and computational physical chemistry in order to investigate a novel bio-synthetic compound and its energy transfer capabilities. This particular peptide-based design has never been studied via Molecular Dynamics with high precision, and it is the first attempt known to us to simulate the whole chromophore-peptide complex in solution in order to gain detailed information about its structural and dynamic features. The fourth chapter deals with the non-equilibrium relaxation induced transport of water molecules in a microemulsion. This problem required a different set of methodologies and a more detailed, all-atomistic treatment of the system. We found interesting water clustering effects and elucidated the most probable mechanism of water transfer through oil under the condition of saturated Langmuir monolayers. Together these computational and theoretical studies compose a powerful and diverse set of physical approaches and both analytical and numerical methodologies, that can be successfully applied in the fields of biology, chemistry and biophysics.

Minakova, Maria S.

343

MOSFET substrate current model for circuit simulation  

Microsoft Academic Search

A simple, accurate MOSFET substrate current model suitable for a circuit simulator is presented. The effect of substrate bias on substrate current is modeled without introducing additional parameters. The accuracy of this model is demonstrated by its ability to fit the experimental data for both standard and LDD devices with average errors of less than 6%. The new model is

Narain D. Arora; Mahesh S. Sharma

1991-01-01

344

Simulation model for aircraft line maintenance planning  

Microsoft Academic Search

This paper reports results of research that developed a computerized simulation model for the aircraft line maintenance department in Continental Airlines. The original AUTOMOD model that was created duplicated the maintenance operations at Continental's major maintenance station at Newark. Modeling the day-to-day maintenance activities lead to the development of enhanced staffing models and a better understanding of resource requirements on

P. Gupta; M. Bazargan; R. N. McGrath

2003-01-01

345

Qualitative Simulation Model for Software Engineering Process  

Microsoft Academic Search

Software process simulation models hold out the promise of improving project planning and control. However, quantitative models require a very detailed understanding of the software process. In particular, process knowledge needs to be represented quantitatively which requires extensive, reliable software project data. When such data is lacking, quantitative models must impose severe constraints, restricting the value of the models. In

He Zhang; Ming Huo; Barbara Kitchenham; D. Ross Jeffery

2006-01-01

346

Simulation of geological models using multipoint histogram  

SciTech Connect

Simulated annealing optimization technique was used to simulate geological models. After comparing one-point perturbation scheme with two-point swapping scheme, and the Metropolis algorithm with the greedy algorithm, an optimized combination of simulated annealing schedule is presented. The two-dimensional correlation coefficient matrix is introduced to determine a unit configuration which can represent essential features of a geological model. The proposed simulated annealing technique can be used to reproduce the characteristics of a geological model based on multipoint histogram which can be obtained by using a unit configuration. Various geological vertical cross sections and horizontal slices based on field data are used to validate this new technique. Simulated results confirm that one-point perturbation scheme with the Metropolis algorithm provides the best combination to capture the essential features of a geological model. Further, the two-dimensional correlation coefficient matrix provides a technique to choose a priori unit configuration for multipoint histogram, which captures the geological characteristics adequately.

Qiu, W.Y.; Kelkar, M.G. [SPE, Richardson, TX (United States); [Univ. of Tulsa, OK (United States)

1995-12-31

347

Protein Simulation Data in the Relational Model  

PubMed Central

High performance computing is leading to unprecedented volumes of data. Relational databases offer a robust and scalable model for storing and analyzing scientific data. However, these features do not come without a cost—significant design effort is required to build a functional and efficient repository. Modeling protein simulation data in a relational database presents several challenges: the data captured from individual simulations are large, multi-dimensional, and must integrate with both simulation software and external data sites. Here we present the dimensional design and relational implementation of a comprehensive data warehouse for storing and analyzing molecular dynamics simulations using SQL Server. PMID:23204646

Simms, Andrew M.; Daggett, Valerie

2011-01-01

348

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

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

349

Modeling and simulation of luminescence detection platforms  

Microsoft Academic Search

Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux

Khaled Salama; Helmy Eltoukhy; Arjang Hassibi; Abbas El Gamal

2004-01-01

350

Design and simulation of advanced fault tolerant flight control schemes  

NASA Astrophysics Data System (ADS)

This research effort describes the design and simulation of a distributed Neural Network (NN) based fault tolerant flight control scheme and the interface of the scheme within a simulation/visualization environment. The goal of the fault tolerant flight control scheme is to recover an aircraft from failures to its sensors or actuators. A commercially available simulation package, Aviator Visual Design Simulator (AVDS), was used for the purpose of simulation and visualization of the aircraft dynamics and the performance of the control schemes. For the purpose of the sensor failure detection, identification and accommodation (SFDIA) task, it is assumed that the pitch, roll and yaw rate gyros onboard are without physical redundancy. The task is accomplished through the use of a Main Neural Network (MNN) and a set of three De-Centralized Neural Networks (DNNs), providing analytical redundancy for the pitch, roll and yaw gyros. The purpose of the MNN is to detect a sensor failure while the purpose of the DNNs is to identify the failed sensor and then to provide failure accommodation. The actuator failure detection, identification and accommodation (AFDIA) scheme also features the MNN, for detection of actuator failures, along with three Neural Network Controllers (NNCs) for providing the compensating control surface deflections to neutralize the failure induced pitching, rolling and yawing moments. All NNs continue to train on-line, in addition to an offline trained baseline network structure, using the Extended Back-Propagation Algorithm (EBPA), with the flight data provided by the AVDS simulation package. The above mentioned adaptive flight control schemes have been traditionally implemented sequentially on a single computer. This research addresses the implementation of these fault tolerant flight control schemes on parallel and distributed computer architectures, using Berkeley Software Distribution (BSD) sockets and Message Passing Interface (MPI) for inter-process communication.

Gururajan, Srikanth

351

Automated Design of Mechatronic Systems using Bond-Graph Modeling and Simulation and Genetic Programming  

Microsoft Academic Search

All modern dynamic engineering systems can be characterized as mechatronic systems. The multi-domain nature of a mechatronic system makes it difficult to model using a single modeling technique over the whole system as varying sets of system variables are required. Bond-Graphs offer an advanced object oriented modeling and simulation technique. They are domain independent allowing straight forward and efficient model

S. A. Kayani; M. Afaalalik

2007-01-01

352

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

NASA Astrophysics Data System (ADS)

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.

LeSueur, Kenneth G.; Almendinger, Frank J.

2007-04-01

353

Desdemona: Advanced Disorientation Trainer and (sustained-G) Flight Simulator  

Microsoft Academic Search

Desdemona is a sophisticated demonstration, simulation, training and research facility specified by TNO Human Factors and developed by AMST Systemtechnik. The Desdemona concept adds a sustainable G-load to the conventional Stewart platform motion, without the angular accelerations encountered in centrifuges during the G-onset. This is accomplished by having the aviator sitting in a fully gimballed cockpit with four cascaded degrees

Bernd de Graaf; Willem Bles; Ruud J. A. W. Hosman

354

Interactive Visualization to Advance Earthquake Simulation LOUISE H. KELLOGG,1  

E-print Network

in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate's surface and interior. Virtual mapping tools allow virtual ``field studies'' in inaccessible regions from numerical simulation or field observations, thereby enabling us to improve our interpretation

Billen, Magali I.

355

Software-Engineering Process Simulation (SEPS) model  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

356

SIMULATION MODELING OF GASTROINTESTINAL ABSORPTION  

EPA Science Inventory

Mathematical dosimetry models incorporate mechanistic determinants of chemical disposition in a living organism to describe relationships between exposure concentration and the internal dose needed for PBPK models and human health risk assessment. Because they rely on determini...

357

Modeling Advanced Avalanche Effects for Bipolar Transistor Circuit Design  

E-print Network

Modeling Advanced Avalanche Effects for Bipolar Transistor Circuit Design Vladimir Milovanovi operating frequency and high output power of modern bipolar transistor circuits increase, designers are trying to exploit transistor operating regions where they would be able satisfy both conditions, namely

Technische Universiteit Delft

358

76 FR 68011 - Medicare Program; Advanced Payment Model  

Federal Register 2010, 2011, 2012, 2013

...Advance Payment Model for certain accountable care organizations participating in...partner with groups of health care providers of services and suppliers...governance that have formed an Accountable Care Organization (ACO) through...

2011-11-02

359

Mechanism simulation with Working Model  

Microsoft Academic Search

Kinematics is a study of motion and force of linkages, gear trains and cams. To many students, visualizing the motion of a mechanism is very challenging. Physical models can be built to illustrate the motion, and modular models using Tinkertoy or Lego are also effective. However, the link lengths of these models are fixed to some extent, and the physical

Shih-Liang Wang

1996-01-01

360

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

E-print Network

agent models (predator-prey systems, battlefield simulations, robot tanks, robot soccer), planetary planted at the centre of the image is gradually grown by releasing "walker" particles around about it. The walkers diffuse randomly and attach themselves to the growing aggregate. This cluster was grown

Hawick, Ken

361

Modeling Physics with Easy Java Simulations  

NSDL National Science Digital Library

The paper Modeling Physics with Easy Java Simulations describes the use of the Easy Java Simulations (Ejs) modeling and authoring tool and shows how this tool can be used to teach mechanics concepts using computer modeling. Although the modeling method can be used without computers, the use of computers allows students to study problems that are difficult and time consuming, to visualize their results, and to communicate their results with others. The combination of computer modeling with theory and experiment can achieve insight and understanding that cannot be achieved with only one approach. Journal article available from http://scitation.aip.org/tpt/

Christian, Wolfgang; Franciscouembre

2008-05-30

362

Modelling and Simulation of Pedestrian Behaviours  

Microsoft Academic Search

The modelling and simulation of autonomous pedestrians has important applications in real-time crowd and crisis simulations. With the increase in processing powers and dedicated graphics cards, more processing powers can now be allocated for the generation of realistic behaviours for individuals within the crowd. We have proposed a representation for autonomous agents that is aimed to generate some human-like behaviours.

W. L. Koh; Lin Lin; Suiping Zhou

2008-01-01

363

Compressible Homogeneous Shear: Simulation and Modeling \\Lambda  

E-print Network

Compressible Homogeneous Shear: Simulation and Modeling \\Lambda S. Sarkar, G. Erlebacher, and M numerical simulation of homogeneous shear flow. A primary observation is that the growth of the turbulent and Engineering (ICASE), NASA Langley Research Center, Hampton, VA 23665. i #12; 1 Introduction Homogeneous

Erlebacher, Gordon

364

Consequence modeling using the fire dynamics simulator  

Microsoft Academic Search

The use of Computational Fluid Dynamics (CFD) and in particular Large Eddy Simulation (LES) codes to model fires provides an efficient tool for the prediction of large-scale effects that include plume characteristics, combustion product dispersion, and heat effects to adjacent objects. This paper illustrates the strengths of the Fire Dynamics Simulator (FDS), an LES code developed by the National Institute

Noah L. Ryder; Jason A. Sutula; Christopher F. Schemel; Andrew J. Hamer; Vincent Van Brunt

2004-01-01

365

Enterprise Modeling and Simulation Within Enterprise Engineering  

Microsoft Academic Search

One of the strengths of simulation as a method of inquiry and tool of study is its ability to provide a platform for breakthrough ideas in emerging interdisciplinary fields. In this article, the author defines enterprise engineering as an interdisciplinary field and discusses the role of modeling and simulation and its potential in enterprise engineering. In particular, the author discusses

Joseph Barjis

2011-01-01

366

Observations and simulations improve space weather models  

E-print Network

- 1 - Observations and simulations improve space weather models June 25, 2014 Los Alamos with fast-moving particles and a space weather system that varies in response to incoming energy computer simulations of the space weather that can affect vital technology, communication and navigation

367

The Simulation of a Jumbo Jet Transport Aircraft. Volume 2: Modeling Data  

NASA Technical Reports Server (NTRS)

The manned simulation of a large transport aircraft is described. Aircraft and systems data necessary to implement the mathematical model described in Volume I and a discussion of how these data are used in model are presented. The results of the real-time computations in the NASA Ames Research Center Flight Simulator for Advanced Aircraft are shown and compared to flight test data and to the results obtained in a training simulator known to be satisfactory.

Hanke, C. R.; Nordwall, D. R.

1970-01-01

368

Simulating data processing for an Advanced Ion Mobility Mass Spectrometer  

SciTech Connect

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.

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

2007-11-03

369

AMERICA'S CUP YACHT DESIGN USING ADVANCED NUMERICAL FLOW SIMULATIONS  

Microsoft Academic Search

La conception d'un voilier moderne de type 'Class America' s'appuie sur l'utilisation de simulations nu- mériques de l'écoulement afin d'obtenir des prestations compétitives. Le calcul des écoulements hydrodynami- que et aérodynamique autour de voiliers est, de toute manière, extremement exigeant; il requiert la technolo- gie informatique et les techniques numériques les plus avangardistes. Un certain nombre de problèmes, criti- ques

MARIO CAPONNETTO; ALESSANDRO CASTELLI; BERNARD BONJOUR; PIERRE-LOUIS MATHEY; STEPHANE SANCHI; MARK L. SAWLEY

370

ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS  

SciTech Connect

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or a globally with physical profile variation. Rohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, plasma pinches and impurity flow, and simulations at fixed flow rather than fixed gradient are illustrated and discussed.

WALTZ RE; CANDY J; HINTON FL; ESTRADA-MILA C; KINSEY JE

2004-10-01

371

Maintenance Personnel Performance Simulation (MAPPS) model  

SciTech Connect

A stochastic computer model for simulating the actions and behavior of nuclear power plant maintenance personnel is described. The model considers personnel, environmental, and motivational variables to yield predictions of maintenance performance quality and time to perform. The mode has been fully developed and sensitivity tested. Additional evaluation of the model is now taking place.

Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.; Haas, P.M.

1984-01-01

372

On Computer Simulation Models of RSW Process  

Microsoft Academic Search

Due to its high complicacy and transitoriness and closeness, resistance spot welding (RSW), which is widely employed as a major sheet metal joining technology in automotive industry, has attracted specific attentions for computer simulations since last century. In this paper, four major RSW numerical models, namely thermal model, electro-thermal model, electro-thermo-mechanical model and electro-thermal model with fluid flow field, are

Haining Zheng; Yongbing Li

2009-01-01

373

Transportation Analysis, Modeling, and Simulation (TAMS) Application  

E-print Network

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

374

A Simulation To Model Exponential Growth.  

ERIC Educational Resources Information Center

Describes a simulation using dice-tossing students in a population cluster to model the growth of cancer cells. This growth is recorded in a scatterplot and compared to an exponential function graph. (KHR)

Appelbaum, Elizabeth Berman

2000-01-01

375

Modelling Reactive and Proactive Behaviour in Simulation  

E-print Network

This research investigated the simulation model behaviour of a traditional and combined discrete event as well as agent based simulation models when modelling human reactive and proactive behaviour in human centric complex systems. A departmental store was chosen as human centric complex case study where the operation system of a fitting room in WomensWear department was investigated. We have looked at ways to determine the efficiency of new management policies for the fitting room operation through simulating the reactive and proactive behaviour of staff towards customers. Once development of the simulation models and their verification had been done, we carried out a validation experiment in the form of a sensitivity analysis. Subsequently, we executed a statistical analysis where the mixed reactive and proactive behaviour experimental results were compared with some reactive experimental results from previously published works. Generally, this case study discovered that simple proactive individual behaviou...

Majid, Mazlina Abdul; Aickelin, Uwe

2010-01-01

376

MODELING CONCEPTS FOR BMP/LID SIMULATION  

EPA Science Inventory

Enhancement of simulation options for stormwater best management practices (BMPs) and hydrologic source control is discussed in the context of the EPA Storm Water Management Model (SWMM). Options for improvement of various BMP representations are presented, with emphasis on inco...

377

Aggregate calibration of microscopic traffic simulation models  

E-print Network

The problem of calibration of microscopic simulation models with aggregate data has received significant attention in recent years. But day-to-day variability in inputs such as travel demand has not been considered. In ...

Mahanti, Bhanu Prasad, 1981-

2004-01-01

378

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

379

Modeling and simulation of dielectric elastomer actuators  

NASA Astrophysics Data System (ADS)

Dielectric elastomers are used as base material for so-called electroactive polymer (EAP) actuators. A procedure and a specific constitutive model (for the acrylic elastomer VHB 4910) are presented in this work for finite element modeling and simulation of dielectric elastomer actuators of general shape and set-up. The Yeoh strain energy potential and the Prony series are used for describing the large strain time-dependent mechanical response of the dielectric elastomer. Material parameters were determined from uniaxial experiments (relaxation tests and tensile tests). Thereby the inverse problem was solved using iterative finite element calculations. A pre-strained circular actuator was built and activated with a predefined voltage. A three-dimensional finite element model of the circular actuator was created and the electromechanical activation process simulated. Simulation and actual measurements agree to a great extent, thus leading to a validation of both the constitutive model and the actuator simulation procedure proposed in this work.

Wissler, Michael; Mazza, Edoardo

2005-12-01

380

Fuzzy Modeling with Adaptive Simulated Annealing  

E-print Network

approach uses Takagi-Sugeno models and Adaptive Simulated Annealing (ASA) to .... At first , and to investigate the efficiency of the ASA method in this kind of .... Kohonen SOM ( Self Organizing Map ) to realize the clustering ( or vector.

381

MATHEMATICAL MODELING OF SIMULATED PHOTOCHEMICAL SMOG  

EPA Science Inventory

This report deals with the continuing effort to develop a chemical kinetic mechanism to describe the formation of photochemical smog. Using the technique of computer modeling to simulate smog chamber data, several explicit kinetic mechanisms for specific hydrocarbons were analyze...

382

Virtual Environments for Advanced Modeling: Conceptual Foundations for Research  

Microsoft Academic Search

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 \\

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

2005-01-01

383

Cruise noise measurements of a scale model advanced ducted propulsor  

Microsoft Academic Search

A scale model Advanced Ducted Propulsor (ADP) was tested in NASA Lewis Research Center's 8- by 6-Foot Wind Tunnel to obtain acoustic data at cruise conditions. The model, designed and manufactured by Pratt & Whitney Division of United Technologies, was tested with three inlet lengths. The model has 16 rotor blades and 22 stator vanes, which results in a cut-on

James H. Dittmar; Christopher E. Hughes; Lawrence A. Bock; David G. Hall

1993-01-01

384

Advanced numerical models and material characterisation techniques for composite materials subject to impact and shock wave loading  

Microsoft Academic Search

The development and validation of an advanced material model for orthotropic materials, such as fibre reinforced composites, is described. The model is specifically designed to facilitate the numerical simulation of impact and shock wave propagation through orthotropic materials and the prediction of subsequent material damage. Initial development of the model concentrated on correctly representing shock wave propagation in composite materials

R. A. Clegg; D. M. White; C. Hayhurst; W. Ridel; W. Harwick; S. Hiermaier

2003-01-01

385

Methodology for accurate and rapid simulation of large arbitrary 2D layouts of advanced photomasks  

NASA Astrophysics Data System (ADS)

The edge domain decomposition method (edge-DDM) is developed as a very powerful extension of the domain decomposition methods presented for the rapid and accurate simulation of light scattering from advanced photomasks. The range of validity of the method is systematically evaluated and it is found to be accurate for wavelength-sized mask features with large vertical topography. The error associated primarily with neglecting corner effects is seen to concentrate at the extremities of the spectrum of propagating plane waves and is therefore filtered-out by the NA and the larger than one reduction factors in typical projection printing systems. A possible algorithmic implementation of the method, that involves rigorous pre-calculation of the edge-diffraction of all types of edges present in the layout, is presented for the simulation of large and arbitrary 2D layouts of alt. PSMs. A speed-up factor of 172,800 (1sec vs. 2days) is shown in the simulation of simple 3um by 3um (4X) 2D layouts (isolated hole and isolated island) with accuracy better than 99 percent compared to the rigorous 3D simulation of the mask diffraction. An example of the edge-DDM applied on a large 12um by 16um 2D layout of a 0deg/90deg/270deg alt. PSM, where the near fields are estimated in less than 1min, is also presented. Spectral matching of the edge-diffraction with more compact piecewise constant models is shown to lead to additional speed-ups of the edge-DDM.

Adam, Konstantinos; Neureuther, Andrew R.

2002-03-01

386

Verification validation and accreditation of simulation models  

Microsoft Academic Search

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

Osman Balci

1997-01-01

387

Verification, Validation And Accreditation Of Simulation Models  

Microsoft Academic Search

This paper presents guidelines for conducting verification, validation and accreditation (VV&A) of simulation models. Fifteen guiding principles are introduced to help the researchers, practitioners and managers better comprehend 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 in selecting

Osman Balci

1997-01-01

388

Simulation models for terminal homing of KEW  

Microsoft Academic Search

Generic models for a realistic simulation of a kinetic energy weapon in the terminal homing mode are studied. While these models are functional in nature and do not describe the hardware characteristics, they do describe the input-output characteristics of the state-of-the-art tactical hardware which they represent. For terminal homing simulation, a KEW was designed in sufficient detail to compute masses

Gano B. Chatterji; Robert D. Curley; Richard A. Bortins

1988-01-01

389

Simulation models for terminal homing of KEW  

NASA Astrophysics Data System (ADS)

Generic models for a realistic simulation of a kinetic energy weapon in the terminal homing mode are studied. While these models are functional in nature and do not describe the hardware characteristics, they do describe the input-output characteristics of the state-of-the-art tactical hardware which they represent. For terminal homing simulation, a KEW was designed in sufficient detail to compute masses and geometric properties such as lengths and center of gravity offsets.

Chatterji, Gano B.; Curley, Robert D.; Bortins, Richard A.

390

Minimum-complexity helicopter simulation math model  

NASA Technical Reports Server (NTRS)

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.

Heffley, Robert K.; Mnich, Marc A.

1988-01-01

391

Advanced terahertz imaging system performance model for concealed weapon identification  

NASA Astrophysics Data System (ADS)

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.

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

392

Tutorial on agent-based modeling and simulation.  

SciTech Connect

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.

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

2005-01-01

393

Advanced flight deck/crew station simulator functional requirements  

NASA Technical Reports Server (NTRS)

This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented.

Wall, R. L.; Tate, J. L.; Moss, M. J.

1980-01-01

394

A simulation model of an insect population  

NSDL National Science Digital Library

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.

0002-11-30

395

Modeling and simulation of mobile satellite propagation  

NASA Technical Reports Server (NTRS)

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.

Barts, R. M.; Stutzman, Warren L.

1992-01-01

396

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

SciTech Connect

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.

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

2011-12-29

397

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

SciTech Connect

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 research, development, and production sites, including understanding the migration and reactions of contaminants in soils and ground water, developing processes for isolation and processing of pollutants, developing 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 TM and S program are fivefold: to apply available electronic structure and dynamics techniques to study fundamental molecular processes involved in the chemistry of natural and contaminated systems; to extend current electronic structure and dynamics techniques to treat molecular systems of future importance and to develop new techniques for addressing problems that are computationally intractable at present; to apply available molecular modeling techniques to simulate molecular processes occurring in the multi-species, multi-phase systems characteristic of natural and polluted environments; to extend current molecular modeling techniques to treat ever more complex molecular systems and to improve the reliability and accuracy of such simulations; and to develop technologies for advanced parallel architectural computer systems. Research highlights of 82 projects are given.

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

1997-01-01

398

ADVANCES IN COMPREHENSIVE GYROKINETIC SIMULATIONS OF TRANSPORT IN TOKAMAKS  

SciTech Connect

A continuum global gyrokinetic code GYRO has been developed to comprehensively simulate core turbulent transport in actual experimental profiles and enable direct quantitative comparisons to the experimental transport flows. GYRO not only treats the now standard ion temperature gradient (ITG) mode turbulence, but also treats trapped and passing electrons with collisions and finite {beta}, equilibrium ExB shear stabilization, and all in real tokamak geometry. Most importantly the code operates at finite relative gyroradius ({rho}{sub *}) so as to treat the profile shear stabilization and nonlocal effects which can break gyroBohm scaling. The code operates in either a cyclic flux-tube limit (which allows only gyroBohm scaling) or globally with physical profile variation. Bohm scaling of DIII-D L-mode has been simulated with power flows matching experiment within error bars on the ion temperature gradient. Mechanisms for broken gyroBohm scaling, neoclassical ion flows embedded in turbulence, turbulent dynamos and profile corrugations, are illustrated.

WALTZ,R.E; CANDY,J; HINTON,F.L; ESTRADA-MILA,C; KINSEY,J.E

2004-10-01

399

Dynamic modeling and optimizations of mechanical prosthetic arm by simulation technique  

Microsoft Academic Search

Simulation of a mechanical system incorporating the biological control has drawn the fascination of researchers' interest in the research field of advanced prosthetic control and artificial intelligence. This paper generates the idea of modeling of a mechanical prosthetic arm via some heuristic applications of simulation techniques. The introductory part of the paper shows the clinical study of an upper limb

Biswarup Neogi; Soumya Ghosal; Sinchan Ghosh; Tridib Kumar Bose; Achintya Das

2012-01-01

400

LAKE WATER TEMPERATURE SIMULATION MODEL  

EPA Science Inventory

Functional relationships to describe surface wind mixing, vertical turbulent diffusion, convective heat transfer, and radiation penetration based on data from lakes in Minnesota have been developed. hese relationships have been introduced by regressing model parameters found eith...

401

Advances in petascale kinetic plasma simulation with VPIC and Roadrunner  

SciTech Connect

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.

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

402

Modeling and simulation of luminescence detection platforms.  

PubMed

Motivated by the design of an integrated CMOS-based detection platform, a simulation model for CCD and CMOS imager-based luminescence detection systems is developed. The model comprises four parts. The first portion models the process of photon flux generation from luminescence probes using ATP-based and luciferase label-based assay kinetics. An optics simulator is then used to compute the incident photon flux on the imaging plane for a given photon flux and system geometry. Subsequently, the output image is computed using a detailed imaging sensor model that accounts for photodetector spectral response, dark current, conversion gain, and various noise sources. Finally, signal processing algorithms are applied to the image to enhance detection reliability and hence increase the overall system throughput. To validate the model, simulation results are compared to experimental results obtained from a CCD-based system that was built to emulate the integrated CMOS-based platform. PMID:15093208

Salama, Khaled; Eltoukhy, Helmy; Hassibi, Arjang; El-Gamal, Abbas

2004-06-15

403

Investigation of advanced fault insertion and simulator methods  

NASA Technical Reports Server (NTRS)

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.

Dunn, W. R.; Cottrell, D.

1986-01-01

404

Simulation and ground testing with the Advanced Video Guidance Sensor  

NASA Technical Reports Server (NTRS)

The Advanced Video Guidance Sensor (AVGS), an active sensor system that provides near-range 6-degree-of-freedom sensor data, has been developed as part of an automatic rendezvous and docking system for the Demonstration of Autonomous Rendezvous Technology (DART). The sensor determines the relative positions and attitudes between the active sensor and the passive target at ranges up to 300 meters. The AVGS uses laser diodes to illuminate retro-reflectors in the target, a solid-state imager to detect the light returned from the target, and image capture electronics and a digital signal processor to convert the video information into the relative positions and attitudes. The development of the sensor, through initial prototypes, final prototypes, and three flight units, has required a great deal of testing at every phase, and the different types of testing, their effectiveness, and their results, are presented in this paper, focusing on the testing of the flight units. Testing has improved the sensor's performance.

Howard, Richard T.; Johnston, Albert S.; Bryan, Thomas C.; Book, Michael L.

2005-01-01

405

Network analyzer calibration methods for high-density packaging characterization and validation of simulation models  

Microsoft Academic Search

A diversity of advanced modeling and simulation tools for application to packaging and interconnect problems have been developed over the past decade. The development of accurate mixed signal and high frequency models requires verification and validation using high frequency measurements. The need for model verification requires accurate measurement calibration for good comparison data. This work compares a variety of calibration

Cynthia L. Hammond; Kathleen L. Virga

2000-01-01

406

An Advanced Sea-Floor Spreading Model.  

ERIC Educational Resources Information Center

Describes models which (1) illustrate spreading that varies in rate from place to place; (2) clearly show transform faults as arcs of small circles; and (3) illustrate what happens near a pole of rotation. The models are easy to construct and have been well received by students. (JN)

Dutch, Steven I.

1986-01-01

407

ABC modeling: advanced features [semiconductor manufacturing  

Microsoft Academic Search

At IBM in Essex Junction, Vermont, an enhanced ABC model is being used not only to assign costs to wafers, but in several new ways that have enabled analysis across multiple dimensions. The model is being used to aid cost reduction activities by providing wafer cost breakdown by process type (e.g., expose, deposition, etch, cleans, measurement), by element (e.g., depreciation,

Stephanie Miraglia; Cathy Blouin; Gary Boldman; Shauna Judd; Thomas Richardson; David Yao

2002-01-01

408

Advances and applications of occupancy models  

USGS Publications Warehouse

We demonstrate the relevance of these definitions by highlighting applications from a single biological system (an amphibian–pathogen system) and discuss situations where the use of occupancy models has been criticized. Finally, we use these applications to suggest future research and model development.

Bailey, Larissa; MacKenzie, Darry I.; Nichols, James D.

2013-01-01

409

Architecting a Simulation Framework for Model Rehosting  

NASA Technical Reports Server (NTRS)

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.

Madden, Michael M.

2004-01-01

410

Modelling and simulation of a distributed battery management system  

Microsoft Academic Search

This paper discusses the modelling and simulation of a distributed battery management system with a continuous and discrete-event simulation environment. The simulation model focuses on replicating the generic components within the system into model blocks to provide a structured approach in simulating battery networks. The simulation model also deals with three key network levels, which are the process level, the

Darren LIM; A. Anbuky

2004-01-01

411

Implementation of Advanced Two Equation Turbulence Models in the USM3D Unstructured Flow Solver  

NASA Technical Reports Server (NTRS)

USM3D is a widely-used unstructured flow solver for simulating inviscid and viscous flows over complex geometries. The current version (version 5.0) of USM3D, however, does not have advanced turbulence models to accurately simulate complicated flow. We have implemented two modified versions of the original Jones and Launder k-epsilon "two-equation" turbulence model and the Girimaji algebraic Reynolds stress model in USM3D. Tests have been conducted for three flat plate boundary layer cases, a RAE2822 airfoil and an ONERA M6 wing. The results are compared with those from direct numerical simulation, empirical formulae, theoretical results, and the existing Spalart-Allmaras one-equation model.

Wang, Qun-Zhen; Massey, Steven J.; Abdol-Hamid, Khaled S.

2000-01-01

412

Atmospheric model intercomparison project: Monsoon simulations  

SciTech Connect

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.

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

413

SIMULATION MODELS OF TRAFFIC FLOW  

Microsoft Academic Search

This paper reviews the range of traffic models, with particular attention to microsimulation. Although there are major types, there are so many hybrids that it is difficult to classify them all. The standard way of assigning traffic to a network is to find a static equilibrium from which no driver would be able to find a quicker route. This gives

John Taplin

414

Digraph reliability model processing advances and applications  

NASA Technical Reports Server (NTRS)

This paper describes a new algorithm, called SourceDoubls, which efficiently solves for singletons and doubletons of a digraph reliability model. Compared with previous methods, the SourceDoubls algorithm provides up to a two order of magnitude reduction in the amount of time required to solve large digraph models. This significant increase in model solution speed allows complex digraphs containing thousands of nodes to be used as knowledge bases for real time automated monitoring and diagnosis applications. Currently, an application to provide monitoring and diagnosis of the Space Station Freedom Data Management System is under development at NASA/Ames Research Center and NASA/Johnson Space Center. This paper contains an overview of this system and provides details of how it will use digraph models processed by the SourceDoubls algorithm to accomplish its task.

Iverson, D. L.; Patterson-Hine, F. A.

1993-01-01

415

Off-gas adsorption model and simulation - OSPREY  

SciTech Connect

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. (author)

Rutledge, V.J. [Idaho National Laboratory, P. O. Box 1625, Idaho Falls, ID (United States)

2013-07-01

416

PROGRESS IN PHOTOCHEMICAL AIR QUALITY SIMULATION MODELING  

EPA Science Inventory

Within the class of existing or conceived photochemical air quality simulation models (PAQSM's) there are only several basic approaches. The United States Environmental Protection Agency (U.S. EPA) in the mid-1970's reviewed the various urban scale models which were in existence ...

417

Transient fault modeling and fault injection simulation  

E-print Network

An accurate transient fault model is presented in this thesis. A 7-term exponential current upset model is derived from the results of a device-level, 3-dimensional, single-event-upset simulation. A curve-fitting algorithm is used to extract...

Yuan, Xuejun

2012-06-07

418

Non-linear transformer modeling and simulation  

SciTech Connect

Transformers models for simulation with Pspice and Analogy`s Saber are being developed using experimental B-H Loop and network analyzer measurements. The models are evaluated for accuracy and convergence using several test circuits. Results are presented which demonstrate the effects on circuit performance from magnetic core losses eddy currents and mechanical stress on the magnetic cores.

Archer, W.E.; Deveney, M.F.; Nagel, R.L.

1994-08-01

419

Univariate input models for stochastic simulation  

Microsoft Academic Search

Techniques are presented for modeling and randomly sampling many of the multivariate probabilistic input processes that drive discrete-event simulation experiments. Emphasis is given to bivariate and trivariate extensions of the univariate beta, Johnson, and Bézier dist ribution families because of the flexibility of these families to model a wide range of shapes for the marginal distributions while also representing the

Michael E. Kuhl; Julie S. Ivy; Emily K. Lada; Natalie M. Steiger; Mary Ann Flanigan Wagner; James R. Wilson

2010-01-01

420

Structural and behavioral equivalence of simulation models  

Microsoft Academic Search

It M sometimes desu-able to know when two different discrete-event simulation models are, in some sense, interchangeable; that is, whether or not the two models always have the same output when run under identical experimental conditions. This notion of behavioral equivalence, while conceptually simple, is difficult to define in a manner that is both useful and testable. It is difficult

Enver Yücesan; Lee Schruben

1992-01-01

421

Verifying and validating a simulation model  

Microsoft Academic Search

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.

Anbin Hu; Ye San; Zicai Wang

2001-01-01

422

Verifying and validating a simulation model  

Microsoft Academic Search

This paper presents the verification and validation of a simulation model with the emphasis on 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 related terms are used in verifying and validating an existing model

Anbin Hu; Ye San; Zicai Wang

2001-01-01

423

Interactively deformable models for surgery simulation  

Microsoft Academic Search

A methodology that addresses important issues concerned with the underlying graphical models designed for surgical simulation, as well as issues related to the real-time interactivity with, and manipulation of, these models is presented. The specific application of interest is laparoscopic surgery, which is performed using endoscopes that present a video image of the organs to the clinicians. The surgeon then

N. F. Ezquerra; J. F. O'Brien; R. Rowe; T. Gadacz; E. Palm

1993-01-01

424

Modeling and simulation of dielectric elastomer actuators  

Microsoft Academic Search

Dielectric elastomers are used as base material for so-called electroactive polymer (EAP) actuators. A procedure and a specific constitutive model (for the acrylic elastomer VHB 4910) are presented in this work for finite element modeling and simulation of dielectric elastomer actuators of general shape and set-up. The Yeoh strain energy potential and the Prony series are used for describing the

Michael Wissler; Edoardo Mazza

2005-01-01

425

Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator  

NASA Technical Reports Server (NTRS)

The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

Garber, Anne E.; Dickens, Ricky E.

2011-01-01

426

The SCEPTRE facility: Improved simulation of the space environment through the application of advanced technology  

NASA Technical Reports Server (NTRS)

SCEPTRE (Space Combined Effects Primary Test Research Equipment) is the Air Force Materials Laboratory's primary device for performance testing of spacecraft thermal control materials. It has been undergoing a major upgrade in the last two years aimed at making it capable of simulating the synergistic effects of vacuum, ultraviolet radiation, and electron radiation. In the course of this work, a number of advances have been made in the areas of computer data processing, solar simulation, and the analysis of test results.

Ruley, J. D.

1984-01-01

427

Development and integration of the Army's advanced multispectral simulation test acceptance resource (AMSTAR) HWIL facilities  

Microsoft Academic Search

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

Kenneth G. LeSueur; William Lowry; Joe Morris

2005-01-01

428

Development and integration of the Army's Advanced Multispectral Simulation Test Acceptance Resource (AMSTAR) HWIL facilities  

Microsoft Academic Search

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

Kenneth G. LeSueur; William Lowry; Joe Morris

2006-01-01

429

Development of advanced driver assistance systems with vehicle hardware-in-the-loop simulations  

Microsoft Academic Search

This paper presents a new method for the design and validation of advanced driver assistance systems (ADASs). With vehicle hardware-in-the-loop (VEHIL) simulations, the development process, and more specifically the validation phase, of intelligent vehicles is carried out safer, cheaper, and is more manageable. In the VEHIL laboratory, a full-scale ADAS-equipped vehicle is set up in a hardware-in-the-loop simulation environment, where

Olaf Gietelink; Jeroen Ploeg; Bart De Schutter; Michel Verhaegen

2006-01-01

430

Recent advances in computational models of natural argument  

Microsoft Academic Search

This paper reviews recent advances in the interdisciplinary area lying between artificial intelligence and the theory of argumentation. The paper has two distinct foci: first, examining the ways in which argumentation has inspired new models of logical and computational intelligence; and second, exploring how AI techniques have been used and extended to model and handle real world argument in a

Chris Reed; Floriana Grasso

2007-01-01

431

Modeling Physics with Easy Java Simulations  

NASA Astrophysics Data System (ADS)

Modeling has been shown to correct weaknesses of traditional instruction by engaging students in the design of physical models to describe, explain, and predict phenomena. Although the modeling method can be used without computers, the use of computers allows students to study problems that are difficult and time consuming, to visualize their results, and to communicate their results with others. This combination of computer modeling with theory and experiment can achieve insight and understanding that cannot be achieved with only one approach. This paper describes the Easy Java Simulations (Ejs) modeling and authoring tool and shows how it can be used to teach mechanics concepts with computer modeling.

Christian, Wolfgang; Esquembre, Francisco

2007-11-01

432

Mars Smart Lander Parachute Simulation Model  

NASA Technical Reports Server (NTRS)

A multi-body flight simulation for the Mars Smart Lander has been developed that includes six degree-of-freedom rigid-body models for both the supersonically-deployed and subsonically-deployed parachutes. This simulation is designed to be incorporated into a larger simulation of the entire entry, descent and landing (EDL) sequence. The complete end-to-end simulation will provide attitude history predictions of all bodies throughout the flight as well as loads on each of the connecting lines. Other issues such as recontact with jettisoned elements (heat shield, back shield, parachute mortar covers, etc.), design of parachute and attachment points, and desirable line properties can also be addressed readily using this simulation.

Queen, Eric M.; Raiszadeh, Ben

2002-01-01

433

Phenomenological Modeling of Infrared Sources: Recent Advances  

NASA Technical Reports Server (NTRS)

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.

Leung, Chun Ming; Kwok, Sun (Editor)

1993-01-01

434

Advancements in the LEWICE Ice Accretion Model  

NASA Technical Reports Server (NTRS)

Recent evidence has shown that the NASA/Lewis Ice Accretion Model, LEWICE, does not predict accurate ice shapes for certain glaze ice conditions. This paper will present the methodology used to make a first attempt at improving the ice accretion prediction in these regimes. Importance is given to the correlations for heat transfer coefficient and ice density, as well as runback flow, selection of the transition point, flow field resolution, and droplet trajectory models. Further improvements and refinement of these modules will be performed once tests in NASA's Icing Research Tunnel, scheduled for 1993, are completed.

Wright, William B.

1993-01-01

435

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.

2007-08-14

436

Development of NASA's Models and Simulations Standard  

NASA Technical Reports Server (NTRS)

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.

Bertch, William J.; Zang, Thomas A.; Steele, Martin J.

2008-01-01

437

A future Outlook: Web based Simulation of Hydrodynamic models  

NASA Astrophysics Data System (ADS)

Despite recent advances to present simulation results as 3D graphs or animation contours, the modeling user community still faces some shortcomings when trying to move around and analyze data. Typical problems include the lack of common platforms with standard vocabulary to exchange simulation results from different numerical models, insufficient descriptions about data (metadata), lack of robust search and retrieval tools for data, and difficulties to reuse simulation domain knowledge. This research demonstrates how to create a shared simulation domain in the WWW and run a number of models through multi-user interfaces. Firstly, meta-datasets have been developed to describe hydrodynamic model data based on geographic metadata standard (ISO 19115) that has been extended to satisfy the need of the hydrodynamic modeling community. The Extended Markup Language (XML) is used to publish this metadata by the Resource Description Framework (RDF). Specific domain ontology for Web Based Simulation (WBS) has been developed to explicitly define vocabulary for the knowledge based simulation system. Subsequently, this knowledge based system is converted into an object model using Meta Object Family (MOF). The knowledge based system acts as a Meta model for the object oriented system, which aids in reusing the domain knowledge. Specific simulation software has been developed based on the object oriented model. Finally, all model data is stored in an object relational database. Database back-ends help store, retrieve and query information efficiently. This research uses open source software and technology such as Java Servlet and JSP, Apache web server, Tomcat Servlet Engine, PostgresSQL databases, Protégé ontology editor, RDQL and RQL for querying RDF in semantic level, Jena Java API for RDF. Also, we use international standards such as the ISO 19115 metadata standard, and specifications such as XML, RDF, OWL, XMI, and UML. The final web based simulation product is deployed as Web Archive (WAR) files which is platform and OS independent and can be used by Windows, UNIX, or Linux. Keywords: Apache, ISO 19115, Java Servlet, Jena, JSP, Metadata, MOF, Linux, Ontology, OWL, PostgresSQL, Protégé, RDF, RDQL, RQL, Tomcat, UML, UNIX, Windows, WAR, XML

Islam, A. S.; Piasecki, M.

2003-12-01