National Library of Energy BETA

Sample records for determination computational modeling

  1. Computational Procedures for Determining Parameters in Ramberg...

    Office of Scientific and Technical Information (OSTI)

    2 RAMBO: A Computer Code for Determining Parameters in Ramberg-Osgood Elastoplastic Model Based on Modulus and Damping Versus Strain ABSTRACT A computer code, RAMBO, is ...

  2. Theory, Modeling and Computation

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

    Theory, Modeling and Computation Theory, Modeling and Computation The sophistication of modeling and simulation will be enhanced not only by the wealth of data available from MaRIE but by the increased computational capacity made possible by the advent of extreme computing. CONTACT Jack Shlachter (505) 665-1888 Email Extreme Computing to Power Accurate Atomistic Simulations Advances in high-performance computing and theory allow longer and larger atomistic simulations than currently possible.

  3. Computational Modeling | Bioenergy | NREL

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

    Computational Modeling NREL uses computational modeling to increase the efficiency of biomass conversion by rational design using multiscale modeling, applying theoretical approaches, and testing scientific hypotheses. model of enzymes wrapping on cellulose; colorful circular structures entwined through blue strands Cellulosomes are complexes of protein scaffolds and enzymes that are highly effective in decomposing biomass. This is a snapshot of a coarse-grain model of complex cellulosome

  4. Determining Memory Use | Argonne Leadership Computing Facility

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

    Allinea DDT Core File Settings Determining Memory Use Using VNC with a Debugger bgq_stack gdb Coreprocessor Runjob termination TotalView Performance Tools & APIs Software & Libraries IBM References Cooley Policies Documentation Feedback Please provide feedback to help guide us as we continue to build documentation for our new computing resource. [Feedback Form] Determining Memory Use Determining the amount of memory available during the execution of the program requires the use of

  5. 2014-02-21 Issuance: Proposed Determination of Computer Servers...

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

    Issuance: Proposed Determination of Computer Servers as a Covered Consumer Product; ... previously proposed determination that computer servers qualify as a covered product, as ...

  6. Computer modeling helps manage wildfires

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

    Computer modeling helps manage wildfires Community Connections: Your link to news and opportunities from Los Alamos National Laboratory Latest Issue: September 1, 2016 all issues All Issues » submit Computer modeling helps manage wildfires Technology increases preparedness, improves firefighting strategies. September 1, 2016 Smoke over the Jemez Mountains during the 2011 Las Conchas wildfire. Smoke over the Jemez Mountains during the 2011 Las Conchas wildfire. Contacts Director, Community

  7. LANL computer model boosts engine efficiency

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

    LANL computer model boosts engine efficiency LANL computer model boosts engine efficiency The KIVA model has been instrumental in helping researchers and manufacturers understand...

  8. Computational procedures for determining parameters in Ramberg...

    Office of Scientific and Technical Information (OSTI)

    A computer code, RAMBO, is developed for obtaining the values of parameters in the ... DAMPING; HYSTERESIS; SHEAR; STRAINS; COMPUTER CODES; MECHANICAL PROPERTIES; TENSILE ...

  9. Improved computer models support genetics research

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

    February Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and...

  10. ELECTRONIC ANALOG COMPUTER FOR DETERMINING RADIOACTIVE DISINTEGRATION

    DOE Patents [OSTI]

    Robinson, H.P.

    1959-07-14

    A computer is presented for determining growth and decay curves for elements in a radioactive disintegration series wherein one unstable element decays to form a second unstable element or isotope, which in turn forms a third element, etc. The growth and decay curves of radioactive elements are simulated by the charge and discharge curves of a resistance-capacitance network. Several such networks having readily adjustable values are connected in series with an amplifier between each successive pair. The time constant of each of the various networks is set proportional to the half-life of a corresponding element in the series represented and the charge and discharge curves of each of the networks simulates the element growth and decay curve.

  11. Parallel computing in enterprise modeling.

    SciTech Connect (OSTI)

    Goldsby, Michael E.; Armstrong, Robert C.; Shneider, Max S.; Vanderveen, Keith; Ray, Jaideep; Heath, Zach; Allan, Benjamin A.

    2008-08-01

    This report presents the results of our efforts to apply high-performance computing to entity-based simulations with a multi-use plugin for parallel computing. We use the term 'Entity-based simulation' to describe a class of simulation which includes both discrete event simulation and agent based simulation. What simulations of this class share, and what differs from more traditional models, is that the result sought is emergent from a large number of contributing entities. Logistic, economic and social simulations are members of this class where things or people are organized or self-organize to produce a solution. Entity-based problems never have an a priori ergodic principle that will greatly simplify calculations. Because the results of entity-based simulations can only be realized at scale, scalable computing is de rigueur for large problems. Having said that, the absence of a spatial organizing principal makes the decomposition of the problem onto processors problematic. In addition, practitioners in this domain commonly use the Java programming language which presents its own problems in a high-performance setting. The plugin we have developed, called the Parallel Particle Data Model, overcomes both of these obstacles and is now being used by two Sandia frameworks: the Decision Analysis Center, and the Seldon social simulation facility. While the ability to engage U.S.-sized problems is now available to the Decision Analysis Center, this plugin is central to the success of Seldon. Because Seldon relies on computationally intensive cognitive sub-models, this work is necessary to achieve the scale necessary for realistic results. With the recent upheavals in the financial markets, and the inscrutability of terrorist activity, this simulation domain will likely need a capability with ever greater fidelity. High-performance computing will play an important part in enabling that greater fidelity.

  12. Computational Model of Magnesium Deposition and Dissolution for Property

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

    Determination via Cyclic Voltammetry - Joint Center for Energy Storage Research June 23, 2016, Research Highlights Computational Model of Magnesium Deposition and Dissolution for Property Determination via Cyclic Voltammetry Top: Example distributions of the charge transfer coefficient and standard heterogeneous rate constant, obtained from fitting Bottom: Comparison between experimental and simulated voltammograms, demonstrating good agreement Scientific Achievement A computationally

  13. Determining Allocation Requirements | Argonne Leadership Computing...

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

    Feedback Form Determining Allocation Requirements Estimating CPU-Hours for ALCF Blue GeneQ Systems When estimating CPU-hours for the ALCF Blue GeneQ systems, it is...

  14. Predictive Capability Maturity Model for computational modeling...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 97 MATHEMATICAL METHODS AND COMPUTING; 99 GENERAL AND MISCELLANEOUSMATHEMATICS, COMPUTING, ...

  15. Cupola Furnace Computer Process Model

    SciTech Connect (OSTI)

    Seymour Katz

    2004-12-31

    The cupola furnace generates more than 50% of the liquid iron used to produce the 9+ million tons of castings annually. The cupola converts iron and steel into cast iron. The main advantages of the cupola furnace are lower energy costs than those of competing furnaces (electric) and the ability to melt less expensive metallic scrap than the competing furnaces. However the chemical and physical processes that take place in the cupola furnace are highly complex making it difficult to operate the furnace in optimal fashion. The results are low energy efficiency and poor recovery of important and expensive alloy elements due to oxidation. Between 1990 and 2004 under the auspices of the Department of Energy, the American Foundry Society and General Motors Corp. a computer simulation of the cupola furnace was developed that accurately describes the complex behavior of the furnace. When provided with the furnace input conditions the model provides accurate values of the output conditions in a matter of seconds. It also provides key diagnostics. Using clues from the diagnostics a trained specialist can infer changes in the operation that will move the system toward higher efficiency. Repeating the process in an iterative fashion leads to near optimum operating conditions with just a few iterations. More advanced uses of the program have been examined. The program is currently being combined with an ''Expert System'' to permit optimization in real time. The program has been combined with ''neural network'' programs to affect very easy scanning of a wide range of furnace operation. Rudimentary efforts were successfully made to operate the furnace using a computer. References to these more advanced systems will be found in the ''Cupola Handbook''. Chapter 27, American Foundry Society, Des Plaines, IL (1999).

  16. Computable General Equilibrium Models for Sustainability Impact...

    Open Energy Info (EERE)

    Publications, Softwaremodeling tools User Interface: Other Website: iatools.jrc.ec.europa.eudocsecolecon2006.pdf Computable General Equilibrium Models for Sustainability...

  17. Climate Modeling using High-Performance Computing

    SciTech Connect (OSTI)

    Mirin, A A

    2007-02-05

    The Center for Applied Scientific Computing (CASC) and the LLNL Climate and Carbon Science Group of Energy and Environment (E and E) are working together to improve predictions of future climate by applying the best available computational methods and computer resources to this problem. Over the last decade, researchers at the Lawrence Livermore National Laboratory (LLNL) have developed a number of climate models that provide state-of-the-art simulations on a wide variety of massively parallel computers. We are now developing and applying a second generation of high-performance climate models. Through the addition of relevant physical processes, we are developing an earth systems modeling capability as well.

  18. Improved computer models support genetics research

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

    February » Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and computational methods provide insight into why genes are activated. February 8, 2013 When complete, these barriers will be a portion of the NMSSUP upgrade. This molecular structure depicts a yeast transfer ribonucleic acid (tRNA), which carries a single amino acid to the ribosome during protein construction. A combined

  19. Improved computer models support genetics research

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

    Simple computer models unravel genetic stress reactions in cells Simple computer models unravel genetic stress reactions in cells Integrated biological and computational methods provide insight into why genes are activated. February 8, 2013 When complete, these barriers will be a portion of the NMSSUP upgrade. This molecular structure depicts a yeast transfer ribonucleic acid (tRNA), which carries a single amino acid to the ribosome during protein construction. A combined experimental and

  20. Low Mach Number Models in Computational Astrophysics

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

    Ann Almgren Low Mach Number Models in Computational Astrophysics February 4, 2014 Ann Almgren. Berkeley Lab Downloads Almgren-nug2014.pdf | Adobe Acrobat PDF file Low Mach Number Models in Computational Astrophysics - Ann Almgren, Berkeley Lab Last edited: 2016-04-29 11:34:50

  1. Determining position inside building via laser rangefinder and handheld computer

    DOE Patents [OSTI]

    Ramsey, Jr. James L.; Finley, Patrick; Melton, Brad

    2010-01-12

    An apparatus, computer software, and a method of determining position inside a building comprising selecting on a PDA at least two walls of a room in a digitized map of a building or a portion of a building, pointing and firing a laser rangefinder at corresponding physical walls, transmitting collected range information to the PDA, and computing on the PDA a position of the laser rangefinder within the room.

  2. LANL computer model boosts engine efficiency

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

    LANL computer model boosts engine efficiency LANL computer model boosts engine efficiency The KIVA model has been instrumental in helping researchers and manufacturers understand combustion processes, accelerate engine development and improve engine design and efficiency. September 25, 2012 KIVA simulation of an experimental engine with DOHC quasi-symmetric pent-roof combustion chamber and 4 valves. KIVA simulation of an experimental engine with DOHC quasi-symmetric pent-roof combustion chamber

  3. Section 23: Models and Computer Codes

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

    Application-2014 for the Waste Isolation Pilot Plant Models and Computer Codes (40 CFR § 194.23) United States Department of Energy Waste Isolation Pilot Plant Carlsbad Field Office Carlsbad, New Mexico Compliance Recertification Application 2014 Models and Computer Codes (40 CFR § 194.23) Table of Contents 23.0 Models and Computer Codes (40 CFR § 194.23) 23.1 Requirements 23.2 40 CFR § 194.23(a)(1) 23.2.1 Background 23.2.2 1998 Certification Decision 23.2.3 Changes in the CRA-2004 23.2.4

  4. Computer Model Buildings Contaminated with Radioactive Material

    Energy Science and Technology Software Center (OSTI)

    1998-05-19

    The RESRAD-BUILD computer code is a pathway analysis model designed to evaluate the potential radiological dose incurred by an individual who works or lives in a building contaminated with radioactive material.

  5. Significant Enhancement of Computational Efficiency in Nonlinear Multiscale Battery Model for Computer Aided Engineering

    SciTech Connect (OSTI)

    Smith, Kandler; Graf, Peter; Jun, Myungsoo; Yang, Chuanbo; Li, Genong; Li, Shaoping; Hochman, Amit; Tselepidakis, Dimitrios

    2015-06-09

    This presentation provides an update on improvements in computational efficiency in a nonlinear multiscale battery model for computer aided engineering.

  6. Preliminary Phase Field Computational Model Development

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Xu, Ke; Suter, Jonathan D.; McCloy, John S.; Johnson, Bradley R.; Ramuhalli, Pradeep

    2014-12-15

    This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in

  7. 2014-02-21 Issuance: Proposed Determination of Computer and Battery...

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

    Proposed Determination of Computer and Battery Backup Systems as a Covered Consumer ... Proposed Determination of Computer and Battery Backup Systems as a Covered Consumer ...

  8. Determining collective barrier operation skew in a parallel computer

    DOE Patents [OSTI]

    Faraj, Daniel A.

    2015-12-24

    Determining collective barrier operation skew in a parallel computer that includes a number of compute nodes organized into an operational group includes: for each of the nodes until each node has been selected as a delayed node: selecting one of the nodes as a delayed node; entering, by each node other than the delayed node, a collective barrier operation; entering, after a delay by the delayed node, the collective barrier operation; receiving an exit signal from a root of the collective barrier operation; and measuring, for the delayed node, a barrier completion time. The barrier operation skew is calculated by: identifying, from the compute nodes' barrier completion times, a maximum barrier completion time and a minimum barrier completion time and calculating the barrier operation skew as the difference of the maximum and the minimum barrier completion time.

  9. Determining collective barrier operation skew in a parallel computer

    SciTech Connect (OSTI)

    Faraj, Daniel A.

    2015-11-24

    Determining collective barrier operation skew in a parallel computer that includes a number of compute nodes organized into an operational group includes: for each of the nodes until each node has been selected as a delayed node: selecting one of the nodes as a delayed node; entering, by each node other than the delayed node, a collective barrier operation; entering, after a delay by the delayed node, the collective barrier operation; receiving an exit signal from a root of the collective barrier operation; and measuring, for the delayed node, a barrier completion time. The barrier operation skew is calculated by: identifying, from the compute nodes' barrier completion times, a maximum barrier completion time and a minimum barrier completion time and calculating the barrier operation skew as the difference of the maximum and the minimum barrier completion time.

  10. Determining Reduced Order Models for Optimal Stochastic Reduced Order Models

    SciTech Connect (OSTI)

    Bonney, Matthew S.; Brake, Matthew R.W.

    2015-08-01

    The use of parameterized reduced order models(PROMs) within the stochastic reduced order model (SROM) framework is a logical progression for both methods. In this report, five different parameterized reduced order models are selected and critiqued against the other models along with truth model for the example of the Brake-Reuss beam. The models are: a Taylor series using finite difference, a proper orthogonal decomposition of the the output, a Craig-Bampton representation of the model, a method that uses Hyper-Dual numbers to determine the sensitivities, and a Meta-Model method that uses the Hyper-Dual results and constructs a polynomial curve to better represent the output data. The methods are compared against a parameter sweep and a distribution propagation where the first four statistical moments are used as a comparison. Each method produces very accurate results with the Craig-Bampton reduction having the least accurate results. The models are also compared based on time requirements for the evaluation of each model where the Meta- Model requires the least amount of time for computation by a significant amount. Each of the five models provided accurate results in a reasonable time frame. The determination of which model to use is dependent on the availability of the high-fidelity model and how many evaluations can be performed. Analysis of the output distribution is examined by using a large Monte-Carlo simulation along with a reduced simulation using Latin Hypercube and the stochastic reduced order model sampling technique. Both techniques produced accurate results. The stochastic reduced order modeling technique produced less error when compared to an exhaustive sampling for the majority of methods.

  11. CDF computing and event data models

    SciTech Connect (OSTI)

    Snider, F.D.; /Fermilab

    2005-12-01

    The authors discuss the computing systems, usage patterns and event data models used to analyze Run II data from the CDF-II experiment at the Tevatron collider. A critical analysis of the current implementation and design reveals some of the stronger and weaker elements of the system, which serve as lessons for future experiments. They highlight a need to maintain simplicity for users in the face of an increasingly complex computing environment.

  12. Computational Tools for Predictive Modeling of Properties in...

    Office of Scientific and Technical Information (OSTI)

    Book: Computational Tools for Predictive Modeling of Properties in Complex Actinide Systems Citation Details In-Document Search Title: Computational Tools for Predictive Modeling ...

  13. Computational Fluid Dynamics Modeling of Diesel Engine Combustion...

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

    Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions 2005 Diesel Engine ...

  14. MaRIE theory, modeling and computation roadmap executive summary...

    Office of Scientific and Technical Information (OSTI)

    Conference: MaRIE theory, modeling and computation roadmap executive summary Citation Details In-Document Search Title: MaRIE theory, modeling and computation roadmap executive ...

  15. Computer Modeling of Chemical and Geochemical Processes in High...

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

    Computer modeling of chemical and geochemical processes in high ionic strength solutions ... in brine Computer modeling of chemical and geochemical processes in high ionic ...

  16. Computationally Efficient Modeling of High-Efficiency Clean Combustion...

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

    More Documents & Publications Computationally Efficient Modeling of High-Efficiency Clean Combustion Engines Computationally Efficient Modeling of High-Efficiency Clean Combustion ...

  17. Towards a Computational Model of a Methane Producing Archaeum...

    Office of Scientific and Technical Information (OSTI)

    Towards a Computational Model of a Methane Producing Archaeum Citation Details In-Document Search Title: Towards a Computational Model of a Methane Producing Archaeum Authors: ...

  18. Computer modeling of the global warming effect

    SciTech Connect (OSTI)

    Washington, W.M.

    1993-12-31

    The state of knowledge of global warming will be presented and two aspects examined: observational evidence and a review of the state of computer modeling of climate change due to anthropogenic increases in greenhouse gases. Observational evidence, indeed, shows global warming, but it is difficult to prove that the changes are unequivocally due to the greenhouse-gas effect. Although observational measurements of global warming are subject to ``correction,`` researchers are showing consistent patterns in their interpretation of the data. Since the 1960s, climate scientists have been making their computer models of the climate system more realistic. Models started as atmospheric models and, through the addition of oceans, surface hydrology, and sea-ice components, they then became climate-system models. Because of computer limitations and the limited understanding of the degree of interaction of the various components, present models require substantial simplification. Nevertheless, in their present state of development climate models can reproduce most of the observed large-scale features of the real system, such as wind, temperature, precipitation, ocean current, and sea-ice distribution. The use of supercomputers to advance the spatial resolution and realism of earth-system models will also be discussed.

  19. Practical Use of Computationally Frugal Model Analysis Methods

    SciTech Connect (OSTI)

    Hill, Mary C.; Kavetski, Dmitri; Clark, Martyn; Ye, Ming; Arabi, Mazdak; Lu, Dan; Foglia, Laura; Mehl, Steffen

    2015-03-21

    Computationally frugal methods of model analysis can provide substantial benefits when developing models of groundwater and other environmental systems. Model analysis includes ways to evaluate model adequacy and to perform sensitivity and uncertainty analysis. Frugal methods typically require 10s of parallelizable model runs; their convenience allows for other uses of the computational effort. We suggest that model analysis be posed as a set of questions used to organize methods that range from frugal to expensive (requiring 10,000 model runs or more). This encourages focus on method utility, even when methods have starkly different theoretical backgrounds. We note that many frugal methods are more useful when unrealistic process-model nonlinearities are reduced. Inexpensive diagnostics are identified for determining when frugal methods are advantageous. Examples from the literature are used to demonstrate local methods and the diagnostics. We suggest that the greater use of computationally frugal model analysis methods would allow questions such as those posed in this work to be addressed more routinely, allowing the environmental sciences community to obtain greater scientific insight from the many ongoing and future modeling efforts

  20. Practical Use of Computationally Frugal Model Analysis Methods

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

    Hill, Mary C.; Kavetski, Dmitri; Clark, Martyn; Ye, Ming; Arabi, Mazdak; Lu, Dan; Foglia, Laura; Mehl, Steffen

    2015-03-21

    Computationally frugal methods of model analysis can provide substantial benefits when developing models of groundwater and other environmental systems. Model analysis includes ways to evaluate model adequacy and to perform sensitivity and uncertainty analysis. Frugal methods typically require 10s of parallelizable model runs; their convenience allows for other uses of the computational effort. We suggest that model analysis be posed as a set of questions used to organize methods that range from frugal to expensive (requiring 10,000 model runs or more). This encourages focus on method utility, even when methods have starkly different theoretical backgrounds. We note that many frugalmore » methods are more useful when unrealistic process-model nonlinearities are reduced. Inexpensive diagnostics are identified for determining when frugal methods are advantageous. Examples from the literature are used to demonstrate local methods and the diagnostics. We suggest that the greater use of computationally frugal model analysis methods would allow questions such as those posed in this work to be addressed more routinely, allowing the environmental sciences community to obtain greater scientific insight from the many ongoing and future modeling efforts« less

  1. Significant Enhancement of Computational Efficiency in Nonlinear Multiscale Battery Model for Computer Aided Engineering (Presentation)

    SciTech Connect (OSTI)

    Kim, G.; Pesaran, A.; Smith, K.; Graf, P.; Jun, M.; Yang, C.; Li, G.; Li, S.; Hochman, A.; Tselepidakis, D.; White, J.

    2014-06-01

    This presentation discusses the significant enhancement of computational efficiency in nonlinear multiscale battery model for computer aided engineering in current research at NREL.

  2. Wild Fire Computer Model Helps Firefighters

    ScienceCinema (OSTI)

    Canfield, Jesse

    2014-06-02

    A high-tech computer model called HIGRAD/FIRETEC, the cornerstone of a collaborative effort between U.S. Forest Service Rocky Mountain Research Station and Los Alamos National Laboratory, provides insights that are essential for front-line fire fighters. The science team is looking into levels of bark beetle-induced conditions that lead to drastic changes in fire behavior and how variable or erratic the behavior is likely to be.

  3. COMPUTATIONAL MODELING OF CIRCULATING FLUIDIZED BED REACTORS

    SciTech Connect (OSTI)

    Ibrahim, Essam A

    2013-01-09

    Details of numerical simulations of two-phase gas-solid turbulent flow in the riser section of Circulating Fluidized Bed Reactor (CFBR) using Computational Fluid Dynamics (CFD) technique are reported. Two CFBR riser configurations are considered and modeled. Each of these two riser models consist of inlet, exit, connecting elbows and a main pipe. Both riser configurations are cylindrical and have the same diameter but differ in their inlet lengths and main pipe height to enable investigation of riser geometrical scaling effects. In addition, two types of solid particles are exploited in the solid phase of the two-phase gas-solid riser flow simulations to study the influence of solid loading ratio on flow patterns. The gaseous phase in the two-phase flow is represented by standard atmospheric air. The CFD-based FLUENT software is employed to obtain steady state and transient solutions for flow modulations in the riser. The physical dimensions, types and numbers of computation meshes, and solution methodology utilized in the present work are stated. Flow parameters, such as static and dynamic pressure, species velocity, and volume fractions are monitored and analyzed. The differences in the computational results between the two models, under steady and transient conditions, are compared, contrasted, and discussed.

  4. Computational Science Research in Support of Petascale Electromagnetic Modeling

    SciTech Connect (OSTI)

    Lee, L.-Q.; Akcelik, V; Ge, L; Chen, S; Schussman, G; Candel, A; Li, Z; Xiao, L; Kabel, A; Uplenchwar, R; Ng, C; Ko, K; /SLAC

    2008-06-20

    Computational science research components were vital parts of the SciDAC-1 accelerator project and are continuing to play a critical role in newly-funded SciDAC-2 accelerator project, the Community Petascale Project for Accelerator Science and Simulation (ComPASS). Recent advances and achievements in the area of computational science research in support of petascale electromagnetic modeling for accelerator design analysis are presented, which include shape determination of superconducting RF cavities, mesh-based multilevel preconditioner in solving highly-indefinite linear systems, moving window using h- or p- refinement for time-domain short-range wakefield calculations, and improved scalable application I/O.

  5. Computational social dynamic modeling of group recruitment.

    SciTech Connect (OSTI)

    Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken; Smrcka, Julianne D.; Ko, Teresa H.; Moy, Timothy David; Wu, Benjamin C.

    2004-01-01

    The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.

  6. Computational models of intergroup competition and warfare.

    SciTech Connect (OSTI)

    Letendre, Kenneth; Abbott, Robert G.

    2011-11-01

    This document reports on the research of Kenneth Letendre, the recipient of a Sandia Graduate Research Fellowship at the University of New Mexico. Warfare is an extreme form of intergroup competition in which individuals make extreme sacrifices for the benefit of their nation or other group to which they belong. Among animals, limited, non-lethal competition is the norm. It is not fully understood what factors lead to warfare. We studied the global variation in the frequency of civil conflict among countries of the world, and its positive association with variation in the intensity of infectious disease. We demonstrated that the burden of human infectious disease importantly predicts the frequency of civil conflict and tested a causal model for this association based on the parasite-stress theory of sociality. We also investigated the organization of social foraging by colonies of harvester ants in the genus Pogonomyrmex, using both field studies and computer models.

  7. ONSET OF CHAOS IN A MODEL OF QUANTUM COMPUTATION (Conference...

    Office of Scientific and Technical Information (OSTI)

    Clearly, if this happens in a quantum computer, it may lead to a destruction of the ... Numerical analysis 2 of a simplest model of quantum computer (2D model of 12-spins with ...

  8. Modeling-Computer Simulations At Northern Basin & Range Region...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Pritchett, 2004) Exploration Activity...

  9. Modeling-Computer Simulations At Central Nevada Seismic Zone...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Pritchett, 2004) Exploration...

  10. Modeling-Computer Simulations At Geysers Area (Goff & Decker...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Geysers Area (Goff & Decker, 1983) Exploration Activity Details...

  11. Modeling-Computer Simulations At Dixie Valley Geothermal Area...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wisian & Blackwell, 2004) Exploration...

  12. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1980) Exploration Activity Details...

  13. Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) | Open...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Lewicki & Oldenburg, 2004) Exploration Activity Details Location...

  14. Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Desert Peak Area (Wisian & Blackwell, 2004) Exploration Activity...

  15. Modeling-Computer Simulations (Combs, Et Al., 1999) | Open Energy...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Combs, Et Al., 1999) Exploration Activity Details Location Unspecified...

  16. Modeling-Computer Simulations At Yellowstone Region (Laney, 2005...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Yellowstone Region (Laney, 2005) Exploration Activity Details Location...

  17. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1979) Exploration Activity Details...

  18. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1977) Exploration Activity Details...

  19. Modeling-Computer Simulations (Ozkocak, 1985) | Open Energy Informatio...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Ozkocak, 1985) Exploration Activity Details Location Unspecified...

  20. Modeling-Computer Simulations At White Mountains Area (Goff ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At White Mountains Area (Goff & Decker, 1983) Exploration Activity...

  1. Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Stillwater Area (Wisian & Blackwell, 2004) Exploration Activity...

  2. Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area (Wilt & Haar, 1986)...

  3. Modeling-Computer Simulations At Dixie Valley Geothermal Area...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Kennedy & Soest, 2006) Exploration...

  4. Modeling-Computer Simulations (Ranalli & Rybach, 2005) | Open...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations (Ranalli & Rybach, 2005) Exploration Activity Details Location...

  5. Modeling-Computer Simulations At Raft River Geothermal Area ...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Raft River Geothermal Area (1983) Exploration Activity Details...

  6. Determination of Diffusion Profiles in Altered Wellbore Cement Using X-ray Computed Tomography Methods

    SciTech Connect (OSTI)

    Mason, Harris E.; Walsh, Stuart D. C.; DuFrane, Wyatt L.; Carroll, Susan A.

    2014-06-17

    The development of accurate, predictive models for use in determining wellbore integrity requires detailed information about the chemical and mechanical changes occurring in hardened Portland cements. X-ray computed tomography (XRCT) provides a method that can nondestructively probe these changes in three dimensions. Here, we describe a method for extracting subvoxel mineralogical and chemical information from synchrotron XRCT images by combining advanced image segmentation with geochemical models of cement alteration. The method relies on determining effective linear activity coefficients (ELAC) for the white light source to generate calibration curves that relate the image grayscales to material composition. The resulting data set supports the modeling of cement alteration by CO2-rich brine with discrete increases in calcium concentration at reaction boundaries. The results of these XRCT analyses can be used to further improve coupled geochemical and mechanical models of cement alteration in the wellbore environment.

  7. Predictive Capability Maturity Model for computational modeling and simulation.

    SciTech Connect (OSTI)

    Oberkampf, William Louis; Trucano, Timothy Guy; Pilch, Martin M.

    2007-10-01

    The Predictive Capability Maturity Model (PCMM) is a new model that can be used to assess the level of maturity of computational modeling and simulation (M&S) efforts. The development of the model is based on both the authors experience and their analysis of similar investigations in the past. The perspective taken in this report is one of judging the usefulness of a predictive capability that relies on the numerical solution to partial differential equations to better inform and improve decision making. The review of past investigations, such as the Software Engineering Institute's Capability Maturity Model Integration and the National Aeronautics and Space Administration and Department of Defense Technology Readiness Levels, indicates that a more restricted, more interpretable method is needed to assess the maturity of an M&S effort. The PCMM addresses six contributing elements to M&S: (1) representation and geometric fidelity, (2) physics and material model fidelity, (3) code verification, (4) solution verification, (5) model validation, and (6) uncertainty quantification and sensitivity analysis. For each of these elements, attributes are identified that characterize four increasing levels of maturity. Importantly, the PCMM is a structured method for assessing the maturity of an M&S effort that is directed toward an engineering application of interest. The PCMM does not assess whether the M&S effort, the accuracy of the predictions, or the performance of the engineering system satisfies or does not satisfy specified application requirements.

  8. Review of computational thermal-hydraulic modeling

    SciTech Connect (OSTI)

    Keefer, R.H.; Keeton, L.W.

    1995-12-31

    Corrosion of heat transfer tubing in nuclear steam generators has been a persistent problem in the power generation industry, assuming many different forms over the years depending on chemistry and operating conditions. Whatever the corrosion mechanism, a fundamental understanding of the process is essential to establish effective management strategies. To gain this fundamental understanding requires an integrated investigative approach that merges technology from many diverse scientific disciplines. An important aspect of an integrated approach is characterization of the corrosive environment at high temperature. This begins with a thorough understanding of local thermal-hydraulic conditions, since they affect deposit formation, chemical concentration, and ultimately corrosion. Computational Fluid Dynamics (CFD) can and should play an important role in characterizing the thermal-hydraulic environment and in predicting the consequences of that environment,. The evolution of CFD technology now allows accurate calculation of steam generator thermal-hydraulic conditions and the resulting sludge deposit profiles. Similar calculations are also possible for model boilers, so that tests can be designed to be prototypic of the heat exchanger environment they are supposed to simulate. This paper illustrates the utility of CFD technology by way of examples in each of these two areas. This technology can be further extended to produce more detailed local calculations of the chemical environment in support plate crevices, beneath thick deposits on tubes, and deep in tubesheet sludge piles. Knowledge of this local chemical environment will provide the foundation for development of mechanistic corrosion models, which can be used to optimize inspection and cleaning schedules and focus the search for a viable fix.

  9. Modeling of Geothermal Reservoirs: Fundamental Processes, Computer...

    Open Energy Info (EERE)

    of Geothermal Reservoirs: Fundamental Processes, Computer Simulation and Field Applications Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...

  10. 2014-03-26 Issuance: Proposed Determination of Computer and Battery...

    Energy Savers [EERE]

    and Battery Backup Systems as a Covered Consumer Product; Extension of Public Comment Period 2014-03-26 Issuance: Proposed Determination of Computer and Battery Backup ...

  11. Modeling-Computer Simulations At Dixie Valley Geothermal Area...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Dixie Valley Geothermal Area (Wannamaker, Et Al., 2006) Exploration...

  12. Modeling-Computer Simulations At Obsidian Cliff Area (Hulen,...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Obsidian Cliff Area (Hulen, Et Al., 2003) Exploration Activity Details...

  13. Modeling-Computer Simulations At Walker-Lane Transitional Zone...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Laney, 2005) Exploration...

  14. Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Redondo Geothermal Area (Roberts, Et Al., 1995)...

  15. Modeling-Computer Simulations At Long Valley Caldera Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Pribnow, Et Al., 2003)...

  16. Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Hawthorne Area (Lazaro, Et Al., 2010) Exploration Activity Details...

  17. Modeling-Computer Simulations At Walker-Lane Transitional Zone...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Pritchett, 2004) Exploration...

  18. Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Brown & DuTeaux, 1997) Exploration...

  19. Modeling-Computer Simulations At Coso Geothermal Area (1980)...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (1980) Exploration Activity Details Location Coso...

  20. Modeling-Computer Simulations At Long Valley Caldera Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Newman, Et Al., 2006) Exploration...

  1. Scientists use world's fastest computer to model materials under...

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

    Materials under extreme conditions Scientists use world's fastest computer to model materials under extreme conditions Materials scientists are for the first time attempting to...

  2. Modeling-Computer Simulations At The Needles Area (Bell & Ramelli...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At The Needles Area (Bell & Ramelli, 2009) Exploration Activity Details...

  3. Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fenton Hill HDR Geothermal Area (Goff & Decker, 1983) Exploration...

  4. Modeling-Computer Simulations At Long Valley Caldera Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Farrar, Et Al., 2003) Exploration...

  5. Modeling-Computer Simulations At Central Nevada Seismic Zone...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Central Nevada Seismic Zone Region (Biasi, Et Al., 2009) Exploration...

  6. Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Geothermal Area (Roberts, Et Al.,...

  7. Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett, 2004) Exploration Activity Details...

  8. LANL researchers use computer modeling to study HIV | National...

    National Nuclear Security Administration (NNSA)

    researchers use computer modeling to study HIV | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing...

  9. Modeling-Computer Simulations At Long Valley Caldera Geothermal...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Long Valley Caldera Geothermal Area (Tempel, Et Al., 2011) Exploration...

  10. Modeling-Computer Simulations At Nw Basin & Range Region (Biasi...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Biasi, Et Al., 2009) Exploration Activity...

  11. Modeling-Computer Simulations At Coso Geothermal Area (2000)...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (2000) Exploration Activity Details Location Coso...

  12. Modeling-Computer Simulations At Northern Basin & Range Region...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Al., 2009) Exploration...

  13. Modeling-Computer Simulations At Valles Caldera - Sulphur Springs...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Valles Caldera - Sulphur Springs Geothermal Area (Wilt & Haar, 1986)...

  14. Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Akutan Fumaroles Area (Kolker, Et Al., 2010) Exploration Activity...

  15. Modeling-Computer Simulations At Walker-Lane Transitional Zone...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Biasi, Et Al., 2009) Exploration...

  16. Modeling-Computer Simulations At Coso Geothermal Area (1999)...

    Open Energy Info (EERE)

    navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Coso Geothermal Area (1999) Exploration Activity Details Location Coso...

  17. Modeling-Computer Simulations At Fish Lake Valley Area (Deymonaz...

    Open Energy Info (EERE)

    Fish Lake Valley Area (Deymonaz, Et Al., 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Fish Lake Valley...

  18. New partnership uses advanced computer science modeling to address...

    National Nuclear Security Administration (NNSA)

    New partnership uses advanced computer science modeling to address climate change Friday, August 29, 2014 - 10:26am Several national laboratories and institutions have joined ...

  19. Modeling-Computer Simulations At Nevada Test And Training Range...

    Open Energy Info (EERE)

    Nevada Test And Training Range Area (Sabin, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nevada...

  20. Martin Karplus and Computer Modeling for Chemical Systems

    Office of Scientific and Technical Information (OSTI)

    Information Additional information about Martin Karplus, computer modeling, and chemical systems is available in electronic documents and on the Web. Documents: Comparison of 3D...

  1. Computer-Aided Construction of Chemical Kinetic Models

    SciTech Connect (OSTI)

    Green, William H.

    2014-12-31

    The combustion chemistry of even simple fuels can be extremely complex, involving hundreds or thousands of kinetically significant species. The most reasonable way to deal with this complexity is to use a computer not only to numerically solve the kinetic model, but also to construct the kinetic model in the first place. Because these large models contain so many numerical parameters (e.g. rate coefficients, thermochemistry) one never has sufficient data to uniquely determine them all experimentally. Instead one must work in predictive mode, using theoretical rather than experimental values for many of the numbers in the model, and as appropriate refining the most sensitive numbers through experiments. Predictive chemical kinetics is exactly what is needed for computer-aided design of combustion systems based on proposed alternative fuels, particularly for early assessment of the value and viability of proposed new fuels before those fuels are commercially available. This project was aimed at making accurate predictive chemical kinetics practical; this is a challenging goal which requires a range of science advances. The project spanned a wide range from quantum chemical calculations on individual molecules and elementary-step reactions, through the development of improved rate/thermo calculation procedures, the creation of algorithms and software for constructing and solving kinetic simulations, the invention of methods for model-reduction while maintaining error control, and finally comparisons with experiment. Many of the parameters in the models were derived from quantum chemistry calculations, and the models were compared with experimental data measured in our lab or in collaboration with others.

  2. Unsolicited Projects in 2012: Research in Computer Architecture, Modeling,

    Office of Science (SC) Website

    and Evolving MPI for Exascale | U.S. DOE Office of Science (SC) 2: Research in Computer Architecture, Modeling, and Evolving MPI for Exascale Advanced Scientific Computing Research (ASCR) ASCR Home About Research Applied Mathematics Computer Science Exascale Tools Workshop Programming Challenges Workshop Architectures I Workshop External link Architectures II Workshop External link Next Generation Networking Scientific Discovery through Advanced Computing (SciDAC) ASCR SBIR-STTR Facilities

  3. Ambient temperature modelling with soft computing techniques

    SciTech Connect (OSTI)

    Bertini, Ilaria; Ceravolo, Francesco; Citterio, Marco; Di Pietra, Biagio; Margiotta, Francesca; Pizzuti, Stefano; Puglisi, Giovanni; De Felice, Matteo

    2010-07-15

    This paper proposes a hybrid approach based on soft computing techniques in order to estimate monthly and daily ambient temperature. Indeed, we combine the back-propagation (BP) algorithm and the simple Genetic Algorithm (GA) in order to effectively train artificial neural networks (ANN) in such a way that the BP algorithm initialises a few individuals of the GA's population. Experiments concerned monthly temperature estimation of unknown places and daily temperature estimation for thermal load computation. Results have shown remarkable improvements in accuracy compared to traditional methods. (author)

  4. Computational Fluid Dynamics Modeling of Diesel Engine Combustion and

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

    Emissions | Department of Energy Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions 2005 Diesel Engine Emissions Reduction (DEER) Conference Presentations and Posters 2005_deer_reitz.pdf (682.47 KB) More Documents & Publications Experiments and Modeling of Two-Stage Combustion in Low-Emissions Diesel Engines Comparison of Conventional Diesel and Reactivity Controlled Compression

  5. Modeling-Computer Simulations | Open Energy Information

    Open Energy Info (EERE)

    the risk of inaccurate predictions.1 Potential Pitfalls Uncertainties in initial reservoir conditions and other model inputs can cause inaccuracies in simulations, which...

  6. Improvements in fast-response flood modeling: desktop parallel computing and domain tracking

    SciTech Connect (OSTI)

    Judi, David R; Mcpherson, Timothy N; Burian, Steven J

    2009-01-01

    It is becoming increasingly important to have the ability to accurately forecast flooding, as flooding accounts for the most losses due to natural disasters in the world and the United States. Flood inundation modeling has been dominated by one-dimensional approaches. These models are computationally efficient and are considered by many engineers to produce reasonably accurate water surface profiles. However, because the profiles estimated in these models must be superimposed on digital elevation data to create a two-dimensional map, the result may be sensitive to the ability of the elevation data to capture relevant features (e.g. dikes/levees, roads, walls, etc...). Moreover, one-dimensional models do not explicitly represent the complex flow processes present in floodplains and urban environments and because two-dimensional models based on the shallow water equations have significantly greater ability to determine flow velocity and direction, the National Research Council (NRC) has recommended that two-dimensional models be used over one-dimensional models for flood inundation studies. This paper has shown that two-dimensional flood modeling computational time can be greatly reduced through the use of Java multithreading on multi-core computers which effectively provides a means for parallel computing on a desktop computer. In addition, this paper has shown that when desktop parallel computing is coupled with a domain tracking algorithm, significant computation time can be eliminated when computations are completed only on inundated cells. The drastic reduction in computational time shown here enhances the ability of two-dimensional flood inundation models to be used as a near-real time flood forecasting tool, engineering, design tool, or planning tool. Perhaps even of greater significance, the reduction in computation time makes the incorporation of risk and uncertainty/ensemble forecasting more feasible for flood inundation modeling (NRC 2000; Sayers et al

  7. Systems, methods and computer-readable media to model kinetic performance of rechargeable electrochemical devices

    DOE Patents [OSTI]

    Gering, Kevin L.

    2013-01-01

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics. The computing system also analyzes the cell information of the electrochemical cell with a Butler-Volmer (BV) expression modified to determine exchange current density of the electrochemical cell by including kinetic performance information related to pulse-time dependence, electrode surface availability, or a combination thereof. A set of sigmoid-based expressions may be included with the modified-BV expression to determine kinetic performance as a function of pulse time. The determined exchange current density may be used with the modified-BV expression, with or without the sigmoid expressions, to analyze other characteristics of the electrochemical cell. Model parameters can be defined in terms of cell aging, making the overall kinetics model amenable to predictive estimates of cell kinetic performance along the aging timeline.

  8. Computational Modeling for the American Chemical Society | GE...

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

    Computational Modeling for the American Chemical Society Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new...

  9. Scientists model brain structure to help computers recognize...

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

    The team tried developing a computer model based on human neural structure and function, ... Introspectively, we know that the human brain solves this problem very well. We only have ...

  10. 2014-02-21 Issuance: Proposed Determination of Computer Servers as a

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

    Covered Consumer Product; Withdrawal | Department of Energy Servers as a Covered Consumer Product; Withdrawal 2014-02-21 Issuance: Proposed Determination of Computer Servers as a Covered Consumer Product; Withdrawal This document is a pre-publication Federal Register notice withdrawing the previously proposed determination that computer servers qualify as a covered product, as issued by the Deputy Assistant Secretary for Energy Efficiency on February 21, 2014. Though it is not intended or

  11. 2014-02-21 Issuance: Proposed Determination of Computer and Battery Backup

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

    Systems as a Covered Consumer Product | Department of Energy and Battery Backup Systems as a Covered Consumer Product 2014-02-21 Issuance: Proposed Determination of Computer and Battery Backup Systems as a Covered Consumer Product This document is a pre-publication Federal Register notice of proposed determination regarding computer systems, as issued by the Deputy Assistant Secretary for Energy Efficiency on February 21, 2014. Though it is not intended or expected, should any discrepancy

  12. 2014-03-26 Issuance: Proposed Determination of Computer and Battery Backup

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

    Systems as a Covered Consumer Product; Extension of Public Comment Period | Department of Energy 26 Issuance: Proposed Determination of Computer and Battery Backup Systems as a Covered Consumer Product; Extension of Public Comment Period 2014-03-26 Issuance: Proposed Determination of Computer and Battery Backup Systems as a Covered Consumer Product; Extension of Public Comment Period This document is a pre-publication Federal Register notice extending the public comment period for the

  13. Computational model of miniature pulsating heat pipes.

    SciTech Connect (OSTI)

    Martinez, Mario J.; Givler, Richard C.

    2013-01-01

    The modeling work described herein represents Sandia National Laboratories (SNL) portion of a collaborative three-year project with Northrop Grumman Electronic Systems (NGES) and the University of Missouri to develop an advanced, thermal ground-plane (TGP), which is a device, of planar configuration, that delivers heat from a source to an ambient environment with high efficiency. Work at all three institutions was funded by DARPA/MTO; Sandia was funded under DARPA/MTO project number 015070924. This is the final report on this project for SNL. This report presents a numerical model of a pulsating heat pipe, a device employing a two phase (liquid and its vapor) working fluid confined in a closed loop channel etched/milled into a serpentine configuration in a solid metal plate. The device delivers heat from an evaporator (hot zone) to a condenser (cold zone). This new model includes key physical processes important to the operation of flat plate pulsating heat pipes (e.g. dynamic bubble nucleation, evaporation and condensation), together with conjugate heat transfer with the solid portion of the device. The model qualitatively and quantitatively predicts performance characteristics and metrics, which was demonstrated by favorable comparisons with experimental results on similar configurations. Application of the model also corroborated many previous performance observations with respect to key parameters such as heat load, fill ratio and orientation.

  14. Use Computational Model to Design and Optimize Welding Conditions to

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

    Suppress Helium Cracking during Welding | Department of Energy Use Computational Model to Design and Optimize Welding Conditions to Suppress Helium Cracking during Welding Use Computational Model to Design and Optimize Welding Conditions to Suppress Helium Cracking during Welding Today, welding is widely used for repair, maintenance and upgrade of nuclear reactor components. As a critical technology to extend the service life of nuclear power plants beyond 60 years, weld technology must be

  15. HIV virus spread and evolution studied through computer modeling

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

    HIV and evolution studied through computer modeling HIV virus spread and evolution studied through computer modeling This approach distinguishes between susceptible and infected individuals to capture the full infection history, including contact tracing data for infected individuals. November 19, 2013 Scanning electron micrograph of HIV-1 budding (in green) from cultured lymphocytes. The image has been colored to highlight important features. Scanning electron micrograph of HIV-1 budding (in

  16. Bayesian approaches for combining computational model output and physical

    Office of Scientific and Technical Information (OSTI)

    observations (Conference) | SciTech Connect Bayesian approaches for combining computational model output and physical observations Citation Details In-Document Search Title: Bayesian approaches for combining computational model output and physical observations Authors: Higdon, David M [1] ; Lawrence, Earl [1] ; Heitmann, Katrin [2] ; Habib, Salman [2] + Show Author Affiliations Los Alamos National Laboratory ANL Publication Date: 2011-07-25 OSTI Identifier: 1084581 Report Number(s):

  17. Computer modeling reveals how surprisingly potent hepatitis C drug works

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

    Hepatitis C computer modeling Computer modeling reveals how surprisingly potent hepatitis C drug works A study reveals how daclatasvir targets one of its proteins and causes the fastest viral decline ever seen with anti-HCV drugs - within 12 hours of treatment. February 19, 2013 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy

  18. Computational social network modeling of terrorist recruitment.

    SciTech Connect (OSTI)

    Berry, Nina M.; Turnley, Jessica Glicken; Smrcka, Julianne D.; Ko, Teresa H.; Moy, Timothy David; Wu, Benjamin C.

    2004-10-01

    The Seldon terrorist model represents a multi-disciplinary approach to developing organization software for the study of terrorist recruitment and group formation. The need to incorporate aspects of social science added a significant contribution to the vision of the resulting Seldon toolkit. The unique addition of and abstract agent category provided a means for capturing social concepts like cliques, mosque, etc. in a manner that represents their social conceptualization and not simply as a physical or economical institution. This paper provides an overview of the Seldon terrorist model developed to study the formation of cliques, which are used as the major recruitment entity for terrorist organizations.

  19. Systems, methods and computer-readable media for modeling cell performance fade of rechargeable electrochemical devices

    DOE Patents [OSTI]

    Gering, Kevin L

    2013-08-27

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware periodically samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics of the electrochemical cell. The computing system also develops a mechanistic level model of the electrochemical cell to determine performance fade characteristics of the electrochemical cell and analyzing the mechanistic level model to estimate performance fade characteristics over aging of a similar electrochemical cell. The mechanistic level model uses first constant-current pulses applied to the electrochemical cell at a first aging period and at three or more current values bracketing a first exchange current density. The mechanistic level model also is based on second constant-current pulses applied to the electrochemical cell at a second aging period and at three or more current values bracketing the second exchange current density.

  20. New Computer Model Pinpoints Prime Materials for Carbon Capture

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

    Computer Model Pinpoints Prime Materials for Carbon Capture New Computer Model Pinpoints Prime Materials for Carbon Capture July 17, 2012 NERSC Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 UC Berkeley Contact: Robert Sanders, rsanders@berkeley.edu zeolite350.jpg One of the 50 best zeolite structures for capturing carbon dioxide. Zeolite is a porous solid made of silicon dioxide, or quartz. In the model, the red balls are oxygen, the tan balls are silicon. The blue-green area is where carbon

  1. Integrated Multiscale Modeling of Molecular Computing Devices

    SciTech Connect (OSTI)

    Weinan E

    2012-03-29

    The main bottleneck in modeling transport in molecular devices is to develop the correct formulation of the problem and efficient algorithms for analyzing the electronic structure and dynamics using, for example, the time-dependent density functional theory. We have divided this task into several steps. The first step is to developing the right mathematical formulation and numerical algorithms for analyzing the electronic structure using density functional theory. The second step is to study time-dependent density functional theory, particularly the far-field boundary conditions. The third step is to study electronic transport in molecular devices. We are now at the end of the first step. Under DOE support, we have made subtantial progress in developing linear scaling and sub-linear scaling algorithms for electronic structure analysis. Although there has been a huge amount of effort in the past on developing linear scaling algorithms, most of the algorithms developed suffer from the lack of robustness and controllable accuracy. We have made the following progress: (1) We have analyzed thoroughly the localization properties of the wave-functions. We have developed a clear understanding of the physical as well as mathematical origin of the decay properties. One important conclusion is that even for metals, one can choose wavefunctions that decay faster than any algebraic power. (2) We have developed algorithms that make use of these localization properties. Our algorithms are based on non-orthogonal formulations of the density functional theory. Our key contribution is to add a localization step into the algorithm. The addition of this localization step makes the algorithm quite robust and much more accurate. Moreover, we can control the accuracy of these algorithms by changing the numerical parameters. (3) We have considerably improved the Fermi operator expansion (FOE) approach. Through pole expansion, we have developed the optimal scaling FOE algorithm.

  2. Methodology for characterizing modeling and discretization uncertainties in computational simulation

    SciTech Connect (OSTI)

    ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M.; DIEGERT,KATHLEEN V.

    2000-03-01

    This research effort focuses on methodology for quantifying the effects of model uncertainty and discretization error on computational modeling and simulation. The work is directed towards developing methodologies which treat model form assumptions within an overall framework for uncertainty quantification, for the purpose of developing estimates of total prediction uncertainty. The present effort consists of work in three areas: framework development for sources of uncertainty and error in the modeling and simulation process which impact model structure; model uncertainty assessment and propagation through Bayesian inference methods; and discretization error estimation within the context of non-deterministic analysis.

  3. New partnership uses advanced computer science modeling to address climate

    National Nuclear Security Administration (NNSA)

    change | National Nuclear Security Administration | (NNSA) partnership uses advanced computer science modeling to address climate change Friday, August 29, 2014 - 10:26am Several national laboratories and institutions have joined forces to develop and apply the most complete climate and Earth system model to address the most challenging and demanding climate change issues. Accelerated Climate Modeling for Energy, or ACME, is designed to accelerate the development and application of fully

  4. District-heating strategy model: computer programmer's manual

    SciTech Connect (OSTI)

    Kuzanek, J.F.

    1982-05-01

    The US Department of Housing and Urban Development (HUD) and the US Department of Energy (DOE) cosponsor a program aimed at increasing the number of district heating and cooling (DHC) systems. Such systems can reduce the amount and costs of fuels used to heat and cool buildings in a district. Twenty-eight communities have agreed to aid HUD in a national feasibility assessment of DHC systems. The HUD/DOE program entails technical assistance by Argonne National Laboratory and Oak Ridge National Laboratory. The assistance includes a computer program, called the district heating strategy model (DHSM), that performs preliminary calculations to analyze potential DHC systems. This report describes the general capabilities of the DHSM, provides historical background on its development, and explains the computer installation and operation of the model - including the data file structures and the options. Sample problems illustrate the structure of the various input data files, the interactive computer-output listings. The report is written primarily for computer programmers responsible for installing the model on their computer systems, entering data, running the model, and implementing local modifications to the code.

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

    SciTech Connect (OSTI)

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

    2009-10-12

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

  6. Computer Modeling of Carbon Metabolism Enables Biofuel Engineering (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-09-01

    In an effort to reduce the cost of biofuels, the National Renewable Energy Laboratory (NREL) has merged biochemistry with modern computing and mathematics. The result is a model of carbon metabolism that will help researchers understand and engineer the process of photosynthesis for optimal biofuel production.

  7. Computer Modeling of Saltstone Landfills by Intera Environmental Consultants

    SciTech Connect (OSTI)

    Albenesius, E.L.

    2001-08-09

    This report summaries the computer modeling studies and how the results of these studies were used to estimate contaminant releases to the groundwater. These modeling studies were used to improve saltstone landfill designs and are the basis for the current reference design. With the reference landfill design, EPA Drinking Water Standards can be met for all chemicals and radionuclides contained in Savannah River Plant waste salts.

  8. Scientists use world's fastest computer to model materials under extreme

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

    conditions Materials under extreme conditions Scientists use world's fastest computer to model materials under extreme conditions Materials scientists are for the first time attempting to create atomic-scale models that describe how voids are created, grow, and merge. October 30, 2009 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable

  9. Parallel Computation of the Regional Ocean Modeling System (ROMS)

    SciTech Connect (OSTI)

    Wang, P; Song, Y T; Chao, Y; Zhang, H

    2005-04-05

    The Regional Ocean Modeling System (ROMS) is a regional ocean general circulation modeling system solving the free surface, hydrostatic, primitive equations over varying topography. It is free software distributed world-wide for studying both complex coastal ocean problems and the basin-to-global scale ocean circulation. The original ROMS code could only be run on shared-memory systems. With the increasing need to simulate larger model domains with finer resolutions and on a variety of computer platforms, there is a need in the ocean-modeling community to have a ROMS code that can be run on any parallel computer ranging from 10 to hundreds of processors. Recently, we have explored parallelization for ROMS using the MPI programming model. In this paper, an efficient parallelization strategy for such a large-scale scientific software package, based on an existing shared-memory computing model, is presented. In addition, scientific applications and data-performance issues on a couple of SGI systems, including Columbia, the world's third-fastest supercomputer, are discussed.

  10. Wind energy conversion system analysis model (WECSAM) computer program documentation

    SciTech Connect (OSTI)

    Downey, W T; Hendrick, P L

    1982-07-01

    Described is a computer-based wind energy conversion system analysis model (WECSAM) developed to predict the technical and economic performance of wind energy conversion systems (WECS). The model is written in CDC FORTRAN V. The version described accesses a data base containing wind resource data, application loads, WECS performance characteristics, utility rates, state taxes, and state subsidies for a six state region (Minnesota, Michigan, Wisconsin, Illinois, Ohio, and Indiana). The model is designed for analysis at the county level. The computer model includes a technical performance module and an economic evaluation module. The modules can be run separately or together. The model can be run for any single user-selected county within the region or looped automatically through all counties within the region. In addition, the model has a restart capability that allows the user to modify any data-base value written to a scratch file prior to the technical or economic evaluation. Thus, any user-supplied data for WECS performance, application load, utility rates, or wind resource may be entered into the scratch file to override the default data-base value. After the model and the inputs required from the user and derived from the data base are described, the model output and the various output options that can be exercised by the user are detailed. The general operation is set forth and suggestions are made for efficient modes of operation. Sample listings of various input, output, and data-base files are appended. (LEW)

  11. A New Perspective for the Calibration of Computational Predictor Models.

    SciTech Connect (OSTI)

    Crespo, Luis Guillermo

    2014-11-01

    This paper presents a framework for calibrating computational models using data from sev- eral and possibly dissimilar validation experiments. The offset between model predictions and observations, which might be caused by measurement noise, model-form uncertainty, and numerical error, drives the process by which uncertainty in the models parameters is characterized. The resulting description of uncertainty along with the computational model constitute a predictor model. Two types of predictor models are studied: Interval Predictor Models (IPMs) and Random Predictor Models (RPMs). IPMs use sets to characterize uncer- tainty, whereas RPMs use random vectors. The propagation of a set through a model makes the response an interval valued function of the state, whereas the propagation of a random vector yields a random process. Optimization-based strategies for calculating both types of predictor models are proposed. Whereas the formulations used to calculate IPMs target solutions leading to the interval value function of minimal spread containing all observations, those for RPMs seek to maximize the models' ability to reproduce the distribution of obser- vations. Regarding RPMs, we choose a structure for the random vector (i.e., the assignment of probability to points in the parameter space) solely dependent on the prediction error. As such, the probabilistic description of uncertainty is not a subjective assignment of belief, nor is it expected to asymptotically converge to a fixed value, but instead it is a description of the model's ability to reproduce the experimental data. This framework enables evaluating the spread and distribution of the predicted response of target applications depending on the same parameters beyond the validation domain (i.e., roll-up and extrapolation).

  12. Fast, narrow-band computer model for radiation calculations

    SciTech Connect (OSTI)

    Yan, Z.; Holmstedt, G.

    1997-01-01

    A fast, narrow-band computer model, FASTNB, which predicts the radiation intensity in a general nonisothermal and nonhomogeneous combustion environment, has been developed. The spectral absorption coefficients of the combustion products, including carbon dioxide, water vapor, and soot, are calculated based on the narrow-band model. FASTNB provides an accurate calculation at reasonably high speed. Compared with Grosshandler`s narrow-band model, RADCAL, which has been verified quite extensively against experimental measurements, FASTNB is more than 20 times faster and gives almost exactly the same results.

  13. The origins of computer weather prediction and climate modeling

    SciTech Connect (OSTI)

    Lynch, Peter [Meteorology and Climate Centre, School of Mathematical Sciences, University College Dublin, Belfield (Ireland)], E-mail: Peter.Lynch@ucd.ie

    2008-03-20

    Numerical simulation of an ever-increasing range of geophysical phenomena is adding enormously to our understanding of complex processes in the Earth system. The consequences for mankind of ongoing climate change will be far-reaching. Earth System Models are capable of replicating climate regimes of past millennia and are the best means we have of predicting the future of our climate. The basic ideas of numerical forecasting and climate modeling were developed about a century ago, long before the first electronic computer was constructed. There were several major practical obstacles to be overcome before numerical prediction could be put into practice. A fuller understanding of atmospheric dynamics allowed the development of simplified systems of equations; regular radiosonde observations of the free atmosphere and, later, satellite data, provided the initial conditions; stable finite difference schemes were developed; and powerful electronic computers provided a practical means of carrying out the prodigious calculations required to predict the changes in the weather. Progress in weather forecasting and in climate modeling over the past 50 years has been dramatic. In this presentation, we will trace the history of computer forecasting through the ENIAC integrations to the present day. The useful range of deterministic prediction is increasing by about one day each decade, and our understanding of climate change is growing rapidly as Earth System Models of ever-increasing sophistication are developed.

  14. Final Report: Center for Programming Models for Scalable Parallel Computing

    SciTech Connect (OSTI)

    Mellor-Crummey, John

    2011-09-13

    As part of the Center for Programming Models for Scalable Parallel Computing, Rice University collaborated with project partners in the design, development and deployment of language, compiler, and runtime support for parallel programming models to support application development for the “leadership-class” computer systems at DOE national laboratories. Work over the course of this project has focused on the design, implementation, and evaluation of a second-generation version of Coarray Fortran. Research and development efforts of the project have focused on the CAF 2.0 language, compiler, runtime system, and supporting infrastructure. This has involved working with the teams that provide infrastructure for CAF that we rely on, implementing new language and runtime features, producing an open source compiler that enabled us to evaluate our ideas, and evaluating our design and implementation through the use of benchmarks. The report details the research, development, findings, and conclusions from this work.

  15. Natural Abundance 17O Nuclear Magnetic Resonance and Computational Modeling

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

    Studies of Lithium Based Liquid Electrolytes - Joint Center for Energy Storage Research March 14, 2015, Research Highlights Natural Abundance 17O Nuclear Magnetic Resonance and Computational Modeling Studies of Lithium Based Liquid Electrolytes (Top) Example of natural abundance 17O NMR spectra of LiTFSI in mixture of EC, PC and EMC (4:1:5 by weight). (Bottom) The solvation structure of LiTFSI derived from the results obtained by both NMR and quantum chemistry calculations Scientific

  16. Multiscale Modeling of Malaria | Argonne Leadership Computing Facility

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

    Malaria Authors: Karniadakis, G.E., Parasitic infectious diseases like malaria and certain hereditary hematologic disorders are often associated with major changes in the shape and viscoelastic properties of red blood cells. Such changes can disrupt blood flow and, possibly, brain perfusion, as in the case of cerebral malaria. In recent work on stochastic multiscale models-in conjunction with large-scale parallel computing-we were able to quantify, for the first time, the main biophysical

  17. Advanced Reactor Thermal Hydraulic Modeling | Argonne Leadership Computing

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

    Facility Temperature distribution illustrating thermal striping in a T-junction. Computed on Intrepid with Nek5000 and visualized on Eureka with VisIt at the ALCF. Paul Fischer (ANL), Aleks Obabko (ANL), and Hank Childs (LBNL) Advanced Reactor Thermal Hydraulic Modeling PI Name: Paul Fischer PI Email: fischer@mcs.anl.gov Institution: Argonne National Laboratory Allocation Program: INCITE Allocation Hours at ALCF: 25 Million Year: 2012 Research Domain: Energy Technologies The DOE Nuclear

  18. Martin Karplus and Computer Modeling for Chemical Systems

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

    Martin Karplus and Computer Modeling for Chemical Systems Resources with Additional Information * Karplus Equation Martin Karplus ©Portrait by N. Pitt, 9/10/03 Martin Karplus, the Theodore William Richards Professor of Chemistry Emeritus at Harvard, is one of three winners of the 2013 Nobel Prize in chemistry... The 83-year-old Vienna-born theoretical chemist, who is also affiliated with the Université de Strasbourg, Strasbourg, France, is a 1951 graduate of Harvard College and earned his

  19. A computer program to determine the specific power of prismatic-core reactors

    SciTech Connect (OSTI)

    Dobranich, D.

    1987-05-01

    A computer program has been developed to determine the maximum specific power for prismatic-core reactors as a function of maximum allowable fuel temperature, core pressure drop, and coolant velocity. The prismatic-core reactors consist of hexagonally shaped fuel elements grouped together to form a cylindrically shaped core. A gas coolant flows axially through circular channels within the elements, and the fuel is dispersed within the solid element material either as a composite or in the form of coated pellets. Different coolant, fuel, coating, and element materials can be selected to represent different prismatic-core concepts. The computer program allows the user to divide the core into any arbitrary number of axial levels to account for different axial power shapes. An option in the program allows the automatic determination of the core height that results in the maximum specific power. The results of parametric specific power calculations using this program are presented for various reactor concepts.

  20. computers

    National Nuclear Security Administration (NNSA)

    Each successive generation of computing system has provided greater computing power and energy efficiency.

    CTS-1 clusters will support NNSA's Life Extension Program and...

  1. ONSET OF CHAOS IN A MODEL OF QUANTUM COMPUTATION G. BERMAN; ET...

    Office of Scientific and Technical Information (OSTI)

    OF CHAOS IN A MODEL OF QUANTUM COMPUTATION G. BERMAN; ET AL 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 99 GENERAL AND MISCELLANEOUSMATHEMATICS, COMPUTING, AND...

  2. Computer Modeling of Violent Intent: A Content Analysis Approach

    SciTech Connect (OSTI)

    Sanfilippo, Antonio P.; Mcgrath, Liam R.; Bell, Eric B.

    2014-01-03

    We present a computational approach to modeling the intent of a communication source representing a group or an individual to engage in violent behavior. Our aim is to identify and rank aspects of radical rhetoric that are endogenously related to violent intent to predict the potential for violence as encoded in written or spoken language. We use correlations between contentious rhetoric and the propensity for violent behavior found in documents from radical terrorist and non-terrorist groups and individuals to train and evaluate models of violent intent. We then apply these models to unseen instances of linguistic behavior to detect signs of contention that have a positive correlation with violent intent factors. Of particular interest is the application of violent intent models to social media, such as Twitter, that have proved to serve as effective channels in furthering sociopolitical change.

  3. Determining when a set of compute nodes participating in a barrier operation on a parallel computer are ready to exit the barrier operation

    DOE Patents [OSTI]

    Blocksome, Michael A.

    2011-12-20

    Methods, apparatus, and products are disclosed for determining when a set of compute nodes participating in a barrier operation on a parallel computer are ready to exit the barrier operation that includes, for each compute node in the set: initializing a barrier counter with no counter underflow interrupt; configuring, upon entering the barrier operation, the barrier counter with a value in dependence upon a number of compute nodes in the set; broadcasting, by a DMA engine on the compute node to each of the other compute nodes upon entering the barrier operation, a barrier control packet; receiving, by the DMA engine from each of the other compute nodes, a barrier control packet; modifying, by the DMA engine, the value for the barrier counter in dependence upon each of the received barrier control packets; exiting the barrier operation if the value for the barrier counter matches the exit value.

  4. Model independent determination of the {sigma} pole

    SciTech Connect (OSTI)

    Leutwyler, H.

    2008-08-31

    The first part of this report reviews recent developments at the interface between lattice work on QCD with light dynamical quarks, effective field theory and low energy precision experiments. Then I discuss how dispersion theory can be used to analyze the low energy structure of the {pi}{pi} scattering amplitude in a model independent manner. This leads to an exact formula for the mass and width of the lowest few resonances, in terms of observable quantities. As an application, I consider the pole position of the {sigma}, paying particular to error propagation in the numerical analysis. The report is based on work done in collaboration with Irinel Caprini and Gilberto Colangelo.

  5. Computational modeling for hexcan failure under core distruptive accidental conditions

    SciTech Connect (OSTI)

    Sawada, T.; Ninokata, H.; Shimizu, A.

    1995-09-01

    This paper describes the development of computational modeling for hexcan wall failures under core disruptive accident conditions of fast breeder reactors. A series of out-of-pile experiments named SIMBATH has been analyzed by using the SIMMER-II code. The SIMBATH experiments were performed at KfK in Germany. The experiments used a thermite mixture to simulate fuel. The test geometry of SIMBATH ranged from single pin to 37-pin bundles. In this study, phenomena of hexcan wall failure found in a SIMBATH test were analyzed by SIMMER-II. Although the original model of SIMMER-II did not calculate any hexcan failure, several simple modifications made it possible to reproduce the hexcan wall melt-through observed in the experiment. In this paper the modifications and their significance are discussed for further modeling improvements.

  6. Modeling the Fracture of Ice Sheets on Parallel Computers

    SciTech Connect (OSTI)

    Waisman, Haim; Tuminaro, Ray

    2013-10-10

    The objective of this project was to investigate the complex fracture of ice and understand its role within larger ice sheet simulations and global climate change. This objective was achieved by developing novel physics based models for ice, novel numerical tools to enable the modeling of the physics and by collaboration with the ice community experts. At the present time, ice fracture is not explicitly considered within ice sheet models due in part to large computational costs associated with the accurate modeling of this complex phenomena. However, fracture not only plays an extremely important role in regional behavior but also influences ice dynamics over much larger zones in ways that are currently not well understood. To this end, our research findings through this project offers significant advancement to the field and closes a large gap of knowledge in understanding and modeling the fracture of ice sheets in the polar regions. Thus, we believe that our objective has been achieved and our research accomplishments are significant. This is corroborated through a set of published papers, posters and presentations at technical conferences in the field. In particular significant progress has been made in the mechanics of ice, fracture of ice sheets and ice shelves in polar regions and sophisticated numerical methods that enable the solution of the physics in an efficient way.

  7. Computational fluid dynamic modeling of fluidized-bed polymerization reactors

    SciTech Connect (OSTI)

    Rokkam, Ram

    2012-01-01

    Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.

  8. Computational fluid dynamics modeling of proton exchange membrane fuel cells

    SciTech Connect (OSTI)

    UM,SUKKEE; WANG,C.Y.; CHEN,KEN S.

    2000-02-11

    A transient, multi-dimensional model has been developed to simulate proton exchange membrane (PEM) fuel cells. The model accounts simultaneously for electrochemical kinetics, current distribution, hydrodynamics and multi-component transport. A single set of conservation equations valid for flow channels, gas-diffusion electrodes, catalyst layers and the membrane region are developed and numerically solved using a finite-volume-based computational fluid dynamics (CFD) technique. The numerical model is validated against published experimental data with good agreement. Subsequently, the model is applied to explore hydrogen dilution effects in the anode feed. The predicted polarization cubes under hydrogen dilution conditions are found to be in qualitative agreement with recent experiments reported in the literature. The detailed two-dimensional electrochemical and flow/transport simulations further reveal that in the presence of hydrogen dilution in the fuel stream, hydrogen is depleted at the reaction surface resulting in substantial kinetic polarization and hence a lower current density that is limited by hydrogen transport from the fuel stream to the reaction site.

  9. Computational model for simulation small testing launcher, technical solution

    SciTech Connect (OSTI)

    Chelaru, Teodor-Viorel; Cristian, Barbu; Chelaru, Adrian

    2014-12-10

    The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper is focused on national project 'Suborbital Launcher for Testing' (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital vehicle

  10. Computing

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

    Computing and Storage Requirements Computing and Storage Requirements for FES J. Candy General Atomics, San Diego, CA Presented at DOE Technical Program Review Hilton Washington DC/Rockville Rockville, MD 19-20 March 2013 2 Computing and Storage Requirements Drift waves and tokamak plasma turbulence Role in the context of fusion research * Plasma performance: In tokamak plasmas, performance is limited by turbulent radial transport of both energy and particles. * Gradient-driven: This turbulent

  11. computers

    National Nuclear Security Administration (NNSA)

    California.

    Retired computers used for cybersecurity research at Sandia National...

  12. DETERMINATION OF HLW GLASS MELT RATE USING X-RAY COMPUTED TOMOGRAPHY

    SciTech Connect (OSTI)

    Choi, A.; Miller, D.; Immel, D.

    2011-10-06

    significant amount of glassy material interspersed among the gas bubbles will be excluded, thus underestimating the melt rate. Likewise, if they are drawn too high, many large voids will be counted as glass, thus overestimating the melt rate. As will be shown later in this report, there is also no guarantee that a given distribution of glass and gas bubbles along a particular sectioned plane will always be representative of the entire sample volume. Poor reproducibility seen in some LMR data may be related to these difficulties of the visual method. In addition, further improvement of the existing melt rate model requires that the overall impact of feed chemistry on melt rate be reflected on measured data at a greater quantitative resolution on a more consistent basis than the visual method can provide. An alternate method being pursued is X-ray computed tomography (CT). It involves X-ray scanning of glass samples, performing CT on the 2-D X-ray images to build 3-D volumetric data, and adaptive segmentation analysis of CT results to not only identify but quantify the distinct regions within each sample based on material density and morphologies. The main advantage of this new method is that it can determine the relative local density of the material remaining in the beaker after the heat treatment regardless of its morphological conditions by selectively excluding all the voids greater than a given volumetric pixel (voxel) size, thus eliminating much of the subjectivity involved in the visual method. As a result, the melt rate data obtained from CT scan will give quantitative descriptions not only on the fully-melted glass, but partially-melted and unmelted feed materials. Therefore, the CT data are presumed to be more reflective of the actual melt rate trends in continuously-fed melters than the visual data. In order to test the applicability of X-ray CT scan to the HLW glass melt rate study, several new series of HLW simulant/frit mixtures were melted in the Melt Rate

  13. Determination of lung segments in computed tomography images using the Euclidean distance to the pulmonary artery

    SciTech Connect (OSTI)

    Stoecker, Christina; Moltz, Jan H.; Lassen, Bianca; Kuhnigk, Jan-Martin; Krass, Stefan; Welter, Stefan; Peitgen, Heinz-Otto

    2013-09-15

    Purpose: Computed tomography (CT) imaging is the modality of choice for lung cancer diagnostics. With the increasing number of lung interventions on sublobar level in recent years, determining and visualizing pulmonary segments in CT images and, in oncological cases, reliable segment-related information about the location of tumors has become increasingly desirable. Computer-assisted identification of lung segments in CT images is subject of this work.Methods: The authors present a new interactive approach for the segmentation of lung segments that uses the Euclidean distance of each point in the lung to the segmental branches of the pulmonary artery. The aim is to analyze the potential of the method. Detailed manual pulmonary artery segmentations are used to achieve the best possible segment approximation results. A detailed description of the method and its evaluation on 11 CT scans from clinical routine are given.Results: An accuracy of 2–3 mm is measured for the segment boundaries computed by the pulmonary artery-based method. On average, maximum deviations of 8 mm are observed. 135 intersegmental pulmonary veins detected in the 11 test CT scans serve as reference data. Furthermore, a comparison of the presented pulmonary artery-based approach to a similar approach that uses the Euclidean distance to the segmental branches of the bronchial tree is presented. It shows a significantly higher accuracy for the pulmonary artery-based approach in lung regions at least 30 mm distal to the lung hilum.Conclusions: A pulmonary artery-based determination of lung segments in CT images is promising. In the tests, the pulmonary artery-based determination has been shown to be superior to the bronchial tree-based determination. The suitability of the segment approximation method for application in the planning of segment resections in clinical practice has already been verified in experimental cases. However, automation of the method accompanied by an evaluation on a larger

  14. Computer modeling of active experiments in space plasmas

    SciTech Connect (OSTI)

    Bollens, R.J.

    1993-01-01

    The understanding of space plasmas is expanding rapidly. This is, in large part, due to the ambitious efforts of scientists from around the world who are performing large scale active experiments in the space plasma surrounding the earth. One such effort was designated the Active Magnetospheric Particle Tracer Explorers (AMPTE) and consisted of a series of plasma releases that were completed during 1984 and 1985. What makes the AMPTE experiments particularly interesting was the occurrence of a dramatic anomaly that was completely unpredicted. During the AMPTE experiment, three satellites traced the solar-wind flow into the earth's magnetosphere. One satellite, built by West Germany, released a series of barium and lithium canisters that were detonated and subsequently photo-ionized via solar radiation, thereby creating an artificial comet. Another satellite, built by Great Britain and in the vicinity during detonation, carried, as did the first satellite, a comprehensive set of magnetic field, particle and wave instruments. Upon detonation, what was observed by the satellites, as well as by aircraft and ground-based observers, was quite unexpected. The initial deflection of the ion clouds was not in the ambient solar wind's flow direction ([rvec V]) but rather in the direction transverse to the solar wind and the background magnetic field ([rvec V] [times] [rvec B]). This result was not predicted by any existing theories or simulation models; it is the main subject discussed in this dissertation. A large three dimensional computer simulation was produced to demonstrate that this transverse motion can be explained in terms of a rocket effect. Due to the extreme computer resources utilized in producing this work, the computer methods used to complete the calculation and the visualization techniques used to view the results are also discussed.

  15. Computation Modeling and Assessment of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect (OSTI)

    J. Shingledecker; D. Gandy; N. Cheruvu; R. Wei; K. Chan

    2011-06-21

    Forced outages and boiler unavailability of coal-fired fossil plants is most often caused by fire-side corrosion of boiler waterwalls and tubing. Reliable coatings are required for Ultrasupercritical (USC) application to mitigate corrosion since these boilers will operate at a much higher temperatures and pressures than in supercritical (565 C {at} 24 MPa) boilers. Computational modeling efforts have been undertaken to design and assess potential Fe-Cr-Ni-Al systems to produce stable nanocrystalline coatings that form a protective, continuous scale of either Al{sub 2}O{sub 3} or Cr{sub 2}O{sub 3}. The computational modeling results identified a new series of Fe-25Cr-40Ni with or without 10 wt.% Al nanocrystalline coatings that maintain long-term stability by forming a diffusion barrier layer at the coating/substrate interface. The computational modeling predictions of microstructure, formation of continuous Al{sub 2}O{sub 3} scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. Advanced coatings, such as MCrAl (where M is Fe, Ni, or Co) nanocrystalline coatings, have been processed using different magnetron sputtering deposition techniques. Several coating trials were performed and among the processing methods evaluated, the DC pulsed magnetron sputtering technique produced the best quality coating with a minimum number of shallow defects and the results of multiple deposition trials showed that the process is repeatable. scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. The cyclic oxidation test results revealed that the nanocrystalline coatings offer better oxidation resistance, in terms of weight loss, localized oxidation, and formation of mixed oxides in the Al{sub 2}O{sub 3} scale, than widely used MCrAlY coatings. However, the ultra-fine grain structure in these coatings, consistent with the computational model predictions, resulted in accelerated Al

  16. Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed

    SciTech Connect (OSTI)

    Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li

    2008-05-15

    Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.

  17. CAPE-OPEN compliant stochastic modeling and reduced-order model computation capability for APECS system

    SciTech Connect (OSTI)

    Diwekar, Urmila; Shastri, Yogendra (Vishwamitra Research Institute Clarendon Hills, IL); Subrmanyan, Karthik; Zitney, S.E.

    2007-11-04

    APECS (Advanced Process Engineering Co-Simulator) is an integrated software suite that combines the power of process simulation with high-fidelity, computational fluid dynamics (CFD) for improved design, analysis, and optimization of process engineering systems. The APECS system uses commercial process simulation (e.g., Aspen Plus) and CFD (e.g., FLUENT) software integrated with the process-industry standard CAPE-OPEN (CO) interfaces. This breakthrough capability allows engineers to better understand and optimize the fluid mechanics that drive overall power plant performance and efficiency. The focus of this paper is the CAPE-OPEN complaint stochastic modeling and reduced order model computational capability around the APECS system. The usefulness of capabilities is illustrated with coal fired, gasification based, FutureGen power plant simulation. These capabilities are used to generate efficient reduced order models and optimizing model complexities.

  18. Optimization and Performance Modeling of Stencil Computations on Modern Microprocessors

    SciTech Connect (OSTI)

    Datta, Kaushik; Kamil, Shoaib; Williams, Samuel; Oliker, Leonid; Shalf, John; Yelick, Katherine

    2007-06-01

    Stencil-based kernels constitute the core of many important scientific applications on blockstructured grids. Unfortunately, these codes achieve a low fraction of peak performance, due primarily to the disparity between processor and main memory speeds. In this paper, we explore the impact of trends in memory subsystems on a variety of stencil optimization techniques and develop performance models to analytically guide our optimizations. Our work targets cache reuse methodologies across single and multiple stencil sweeps, examining cache-aware algorithms as well as cache-oblivious techniques on the Intel Itanium2, AMD Opteron, and IBM Power5. Additionally, we consider stencil computations on the heterogeneous multicore design of the Cell processor, a machine with an explicitly managed memory hierarchy. Overall our work represents one of the most extensive analyses of stencil optimizations and performance modeling to date. Results demonstrate that recent trends in memory system organization have reduced the efficacy of traditional cache-blocking optimizations. We also show that a cache-aware implementation is significantly faster than a cache-oblivious approach, while the explicitly managed memory on Cell enables the highest overall efficiency: Cell attains 88% of algorithmic peak while the best competing cache-based processor achieves only 54% of algorithmic peak performance.

  19. Computational modeling of drug-resistant bacteria. Final report

    SciTech Connect (OSTI)

    MacDougall, Preston

    2015-03-12

    Initial proposal summary: The evolution of antibiotic-resistant mutants among bacteria (superbugs) is a persistent and growing threat to public health. In many ways, we are engaged in a war with these microorganisms, where the corresponding arms race involves chemical weapons and biological targets. Just as advances in microelectronics, imaging technology and feature recognition software have turned conventional munitions into smart bombs, the long-term objectives of this proposal are to develop highly effective antibiotics using next-generation biomolecular modeling capabilities in tandem with novel subatomic feature detection software. Using model compounds and targets, our design methodology will be validated with correspondingly ultra-high resolution structure-determination methods at premier DOE facilities (single-crystal X-ray diffraction at Argonne National Laboratory, and neutron diffraction at Oak Ridge National Laboratory). The objectives and accomplishments are summarized.

  20. The use of computed radiography plates to determine light and radiation field coincidence

    SciTech Connect (OSTI)

    Kerns, James R.; Anand, Aman

    2013-11-15

    Purpose: Photo-stimulable phosphor computed radiography (CR) has characteristics that allow the output to be manipulated by both radiation and optical light. The authors have developed a method that uses these characteristics to carry out radiation field and light field coincidence quality assurance on linear accelerators.Methods: CR detectors from Kodak were used outside their cassettes to measure both radiation and light field edges from a Varian linear accelerator. The CR detector was first exposed to a radiation field and then to a slightly smaller light field. The light impinged on the detector's latent image, removing to an extent the portion exposed to the light field. The detector was then digitally scanned. A MATLAB-based algorithm was developed to automatically analyze the images and determine the edges of the light and radiation fields, the vector between the field centers, and the crosshair center. Radiographic film was also used as a control to confirm the radiation field size.Results: Analysis showed a high degree of repeatability with the proposed method. Results between the proposed method and radiographic film showed excellent agreement of the radiation field. The effect of varying monitor units and light exposure time was tested and found to be very small. Radiation and light field sizes were determined with an uncertainty of less than 1 mm, and light and crosshair centers were determined within 0.1 mm.Conclusions: A new method was developed to digitally determine the radiation and light field size using CR photo-stimulable phosphor plates. The method is quick and reproducible, allowing for the streamlined and robust assessment of light and radiation field coincidence, with no observer interpretation needed.

    1. Modeling and Analysis of a Lunar Space Reactor with the Computer...

      Office of Scientific and Technical Information (OSTI)

      Reactor with the Computer Code RELAP5-3DATHENA Citation Details In-Document Search Title: Modeling and Analysis of a Lunar Space Reactor with the Computer Code RELAP5-3D...

    2. Computational Modeling and Assessment Of Nanocoatings for Ultra Supercritical Boilers

      SciTech Connect (OSTI)

      David W. Gandy; John P. Shingledecker

      2011-04-11

      Forced outages and boiler unavailability in conventional coal-fired fossil power plants is most often caused by fireside corrosion of boiler waterwalls. Industry-wide, the rate of wall thickness corrosion wastage of fireside waterwalls in fossil-fired boilers has been of concern for many years. It is significant that the introduction of nitrogen oxide (NOx) emission controls with staged burners systems has increased reported waterwall wastage rates to as much as 120 mils (3 mm) per year. Moreover, the reducing environment produced by the low-NOx combustion process is the primary cause of accelerated corrosion rates of waterwall tubes made of carbon and low alloy steels. Improved coatings, such as the MCrAl nanocoatings evaluated here (where M is Fe, Ni, and Co), are needed to reduce/eliminate waterwall damage in subcritical, supercritical, and ultra-supercritical (USC) boilers. The first two tasks of this six-task project-jointly sponsored by EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)-have focused on computational modeling of an advanced MCrAl nanocoating system and evaluation of two nanocrystalline (iron and nickel base) coatings, which will significantly improve the corrosion and erosion performance of tubing used in USC boilers. The computational model results showed that about 40 wt.% is required in Fe based nanocrystalline coatings for long-term durability, leading to a coating composition of Fe-25Cr-40Ni-10 wt.% Al. In addition, the long term thermal exposure test results further showed accelerated inward diffusion of Al from the nanocrystalline coatings into the substrate. In order to enhance the durability of these coatings, it is necessary to develop a diffusion barrier interlayer coating such TiN and/or AlN. The third task 'Process Advanced MCrAl Nanocoating Systems' of the six-task project jointly sponsored by the Electric Power Research Institute, EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)- has focused on processing of

    3. Computations

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

      Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing ... Heavy Duty Fuels DISI Combustion HCCISCCI Fundamentals Spray Combustion Modeling ...

    4. Computations

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

      Computations - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear Energy

    5. Computing

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

      Office of Advanced Scientific Computing Research in the Department of Energy Office of Science under contract number DE-AC02-05CH11231. ! Application and System Memory Use, Configuration, and Problems on Bassi Richard Gerber Lawrence Berkeley National Laboratory NERSC User Services ScicomP 13 Garching bei München, Germany, July 17, 2007 ScicomP 13, July 17, 2007, Garching Overview * About Bassi * Memory on Bassi * Large Page Memory (It's Great!) * System Configuration * Large Page

    6. final report for Center for Programming Models for Scalable Parallel Computing

      SciTech Connect (OSTI)

      Johnson, Ralph E

      2013-04-10

      This is the final report of the work on parallel programming patterns that was part of the Center for Programming Models for Scalable Parallel Computing

    7. Designing computing system architecture and models for the HL-LHC era

      SciTech Connect (OSTI)

      Bauerdick, L.; Bockelman, B.; Elmer, P.; Gowdy, S.; Tadel, M.; Wurthwein, F.

      2015-01-01

      This work describes a programme to study the computing model in CMS after the next long shutdown near the end of the decade.

    8. Modeling-Computer Simulations At U.S. West Region (Sabin, Et...

      Open Energy Info (EERE)

      navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At U.S. West Region (Sabin, Et Al., 2004) Exploration Activity Details...

    9. Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al...

      Open Energy Info (EERE)

      navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Cove Fort Area (Toksoz, Et Al, 2010) Exploration Activity Details...

    10. Modeling-Computer Simulations At U.S. West Region (Williams ...

      Open Energy Info (EERE)

      navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At U.S. West Region (Williams & Deangelo, 2008) Exploration Activity...

    11. Electrical utilities model for determining electrical distribution capacity

      SciTech Connect (OSTI)

      Fritz, R. L.

      1997-09-03

      In its simplest form, this model was to obtain meaningful data on the current state of the Site`s electrical transmission and distribution assets, and turn this vast collection of data into useful information. The resulting product is an Electrical Utilities Model for Determining Electrical Distribution Capacity which provides: current state of the electrical transmission and distribution systems; critical Hanford Site needs based on outyear planning documents; decision factor model. This model will enable Electrical Utilities management to improve forecasting requirements for service levels, budget, schedule, scope, and staffing, and recommend the best path forward to satisfy customer demands at the minimum risk and least cost to the government. A dynamic document, the model will be updated annually to reflect changes in Hanford Site activities.

    12. Review of the synergies between computational modeling and experimenta...

      Office of Scientific and Technical Information (OSTI)

      length scales, new research directions are emerging in materials science and computational mechanics. ... Report Number(s): SAND--2015-10307J Journal ID: ISSN 0022-2461; PII: ...

    13. High-Performance Computer Modeling of the Cosmos-Iridium Collision

      SciTech Connect (OSTI)

      Olivier, S; Cook, K; Fasenfest, B; Jefferson, D; Jiang, M; Leek, J; Levatin, J; Nikolaev, S; Pertica, A; Phillion, D; Springer, K; De Vries, W

      2009-08-28

      This paper describes the application of a new, integrated modeling and simulation framework, encompassing the space situational awareness (SSA) enterprise, to the recent Cosmos-Iridium collision. This framework is based on a flexible, scalable architecture to enable efficient simulation of the current SSA enterprise, and to accommodate future advancements in SSA systems. In particular, the code is designed to take advantage of massively parallel, high-performance computer systems available, for example, at Lawrence Livermore National Laboratory. We will describe the application of this framework to the recent collision of the Cosmos and Iridium satellites, including (1) detailed hydrodynamic modeling of the satellite collision and resulting debris generation, (2) orbital propagation of the simulated debris and analysis of the increased risk to other satellites (3) calculation of the radar and optical signatures of the simulated debris and modeling of debris detection with space surveillance radar and optical systems (4) determination of simulated debris orbits from modeled space surveillance observations and analysis of the resulting orbital accuracy, (5) comparison of these modeling and simulation results with Space Surveillance Network observations. We will also discuss the use of this integrated modeling and simulation framework to analyze the risks and consequences of future satellite collisions and to assess strategies for mitigating or avoiding future incidents, including the addition of new sensor systems, used in conjunction with the Space Surveillance Network, for improving space situational awareness.

    14. Compensator models for fluence field modulated computed tomography

      SciTech Connect (OSTI)

      Bartolac, Steven; Jaffray, David; Radiation Medicine Program, Princess Margaret Hospital Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9

      2013-12-15

      Purpose: Fluence field modulated computed tomography (FFMCT) presents a novel approach for acquiring CT images, whereby a patient model guides dynamically changing fluence patterns in an attempt to achieve task-based, user-prescribed, regional variations in image quality, while also controlling dose to the patient. This work aims to compare the relative effectiveness of FFMCT applied to different thoracic imaging tasks (routine diagnostic CT, lung cancer screening, and cardiac CT) when the modulator is subject to limiting constraints, such as might be present in realistic implementations.Methods: An image quality plan was defined for a simulated anthropomorphic chest slice, including regions of high and low image quality, for each of the thoracic imaging tasks. Modulated fluence patterns were generated using a simulated annealing optimization script, which attempts to achieve the image quality plan under a global dosimetric constraint. Optimization was repeated under different types of modulation constraints (e.g., fixed or gantry angle dependent patterns, continuous or comprised of discrete apertures) with the most limiting case being a fixed conventional bowtie filter. For each thoracic imaging task, an image quality map (IQM{sub sd}) representing the regionally varying standard deviation is predicted for each modulation method and compared to the prescribed image quality plan as well as against results from uniform fluence fields. Relative integral dose measures were also compared.Results: Each IQM{sub sd} resulting from FFMCT showed improved agreement with planned objectives compared to those from uniform fluence fields for all cases. Dynamically changing modulation patterns yielded better uniformity, improved image quality, and lower dose compared to fixed filter patterns with optimized tube current. For the latter fixed filter cases, the optimal choice of tube current modulation was found to depend heavily on the task. Average integral dose reduction compared

    15. Rapidly re-computable EEG (electroencephalography) forward models for realistic head shapes

      SciTech Connect (OSTI)

      Ermer, J. J.; Mosher, J. C.; Baillet, S.; Leahy, R. M.

      2001-01-01

      Solution of the EEG source localization (inverse) problem utilizing model-based methods typically requires a significant number of forward model evaluations. For subspace based inverse methods like MUSIC [6], the total number of forward model evaluations can often approach an order of 10{sup 3} or 10{sup 4}. Techniques based on least-squares minimization may require significantly more evaluations. The observed set of measurements over an M-sensor array is often expressed as a linear forward spatio-temporal model of the form: F = GQ + N (1) where the observed forward field F (M-sensors x N-time samples) can be expressed in terms of the forward model G, a set of dipole moment(s) Q (3xP-dipoles x N-time samples) and additive noise N. Because of their simplicity, ease of computation, and relatively good accuracy, multi-layer spherical models [7] (or fast approximations described in [1], [7]) have traditionally been the 'forward model of choice' for approximating the human head. However, approximation of the human head via a spherical model does have several key drawbacks. By its very shape, the use of a spherical model distorts the true distribution of passive currents in the skull cavity. Spherical models also require that the sensor positions be projected onto the fitted sphere (Fig. 1), resulting in a distortion of the true sensor-dipole spatial geometry (and ultimately the computed surface potential). The use of a single 'best-fitted' sphere has the added drawback of incomplete coverage of the inner skull region, often ignoring areas such as the frontal cortex. In practice, this problem is typically countered by fitting additional sphere(s) to those region(s) not covered by the primary sphere. The use of these additional spheres results in added complication to the forward model. Using high-resolution spatial information obtained via X-ray CT or MR imaging, a realistic head model can be formed by tessellating the head into a set of contiguous regions (typically the

    16. User's guide for SAMMY: a computer model for multilevel r-matrix fits to neutron data using Bayes' equations

      SciTech Connect (OSTI)

      Larson, N. M.; Perey, F. G.

      1980-11-01

      A method is described for determining the parameters of a model from experimental data based upon the utilization of Bayes' theorem. This method has several advantages over the least-squares method as it is commonly used; one important advantage is that the assumptions under which the parameter values have been determined are more clearly evident than in many results based upon least squares. Bayes' method has been used to develop a computer code which can be utilized to analyze neutron cross-section data by means of the R-matrix theory. The required formulae from the R-matrix theory are presented, and the computer implementation of both Bayes' equations and R-matrix theory is described. Details about the computer code and compelte input/output information are given.

    17. Computer modeling of properties of complex molecular systems

      SciTech Connect (OSTI)

      Kulkova, E.Yu.; Khrenova, M.G.; Polyakov, I.V.

      2015-03-10

      Large molecular aggregates present important examples of strongly nonhomogeneous systems. We apply combined quantum mechanics / molecular mechanics approaches that assume treatment of a part of the system by quantum-based methods and the rest of the system with conventional force fields. Herein we illustrate these computational approaches by two different examples: (1) large-scale molecular systems mimicking natural photosynthetic centers, and (2) components of prospective solar cells containing titan dioxide and organic dye molecules. We demonstrate that modern computational tools are capable to predict structures and spectra of such complex molecular aggregates.

    18. Computational model of collisional-radiative nonequilibrium plasma in an air-driven type laser propulsion

      SciTech Connect (OSTI)

      Ogino, Yousuke; Ohnishi, Naofumi

      2010-05-06

      A thrust power of a gas-driven laser-propulsion system is obtained through interaction with a propellant gas heated by a laser energy. Therefore, understanding the nonequilibrium nature of laser-produced plasma is essential for increasing available thrust force and for improving energy conversion efficiency from a laser to a propellant gas. In this work, a time-dependent collisional-radiative model for air plasma has been developed to study the effects of nonequilibrium atomic and molecular processes on population densities for an air-driven type laser propulsion. Many elementary processes are considered in the number density range of 10{sup 12}/cm{sup 3}<=N<=10{sup 19}/cm{sup 3} and the temperature range of 300 K<=T<=40,000 K. We then compute the unsteady nature of pulsively heated air plasma. When the ionization relaxation time is the same order as the time scale of a heating pulse, the effects of unsteady ionization are important for estimating air plasma states. From parametric computations, we determine the appropriate conditions for the collisional-radiative steady state, local thermodynamic equilibrium, and corona equilibrium models in that density and temperature range.

    19. COMPUTATIONAL FLUID DYNAMICS MODELING OF SCALED HANFORD DOUBLE SHELL TANK MIXING - CFD MODELING SENSITIVITY STUDY RESULTS

      SciTech Connect (OSTI)

      JACKSON VL

      2011-08-31

      The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance at full-scale.

    20. Experimental Determination and Thermodynamic Modeling of Electrical Conductivity of SRS Waste Tank Supernate

      SciTech Connect (OSTI)

      Pike, J.; Reboul, S.

      2015-06-01

      SRS High Level Waste Tank Farm personnel rely on conductivity probes for detection of incipient overflow conditions in waste tanks. Minimal information is available concerning the sensitivity that must be achieved such that that liquid detection is assured. Overly sensitive electronics results in numerous nuisance alarms for these safety-related instruments. In order to determine the minimum sensitivity required of the probe, Tank Farm Engineering personnel need adequate conductivity data to improve the existing designs. Little or no measurements of liquid waste conductivity exist; however, the liquid phase of the waste consists of inorganic electrolytes for which the conductivity may be calculated. Savannah River Remediation (SRR) Tank Farm Facility Engineering requested SRNL to determine the conductivity of the supernate resident in SRS waste Tank 40 experimentally as well as computationally. In addition, SRNL was requested to develop a correlation, if possible, that would be generally applicable to liquid waste resident in SRS waste tanks. A waste sample from Tank 40 was analyzed for composition and electrical conductivity as shown in Table 4-6, Table 4-7, and Table 4-9. The conductivity for undiluted Tank 40 sample was 0.087 S/cm. The accuracy of OLI Analyzer™ was determined using available literature data. Overall, 95% of computed estimates of electrical conductivity are within ±15% of literature values for component concentrations from 0 to 15 M and temperatures from 0 to 125 °C. Though the computational results are generally in good agreement with the measured data, a small portion of literature data deviates as much as ±76%. A simplified model was created that can be used readily to estimate electrical conductivity of waste solution in computer spreadsheets. The variability of this simplified approach deviates up to 140% from measured values. Generally, this model can be applied to estimate the conductivity within a factor of two. The comparison of the

    1. A system analysis computer model for the High Flux Isotope Reactor (HFIRSYS Version 1)

      SciTech Connect (OSTI)

      Sozer, M.C.

      1992-04-01

      A system transient analysis computer model (HFIRSYS) has been developed for analysis of small break loss of coolant accidents (LOCA) and operational transients. The computer model is based on the Advanced Continuous Simulation Language (ACSL) that produces the FORTRAN code automatically and that provides integration routines such as the Gear`s stiff algorithm as well as enabling users with numerous practical tools for generating Eigen values, and providing debug outputs and graphics capabilities, etc. The HFIRSYS computer code is structured in the form of the Modular Modeling System (MMS) code. Component modules from MMS and in-house developed modules were both used to configure HFIRSYS. A description of the High Flux Isotope Reactor, theoretical bases for the modeled components of the system, and the verification and validation efforts are reported. The computer model performs satisfactorily including cases in which effects of structural elasticity on the system pressure is significant; however, its capabilities are limited to single phase flow. Because of the modular structure, the new component models from the Modular Modeling System can easily be added to HFIRSYS for analyzing their effects on system`s behavior. The computer model is a versatile tool for studying various system transients. The intent of this report is not to be a users manual, but to provide theoretical bases and basic information about the computer model and the reactor.

    2. Final Report for Integrated Multiscale Modeling of Molecular Computing Devices

      SciTech Connect (OSTI)

      Glotzer, Sharon C.

      2013-08-28

      In collaboration with researchers at Vanderbilt University, North Carolina State University, Princeton and Oakridge National Laboratory we developed multiscale modeling and simulation methods capable of modeling the synthesis, assembly, and operation of molecular electronics devices. Our role in this project included the development of coarse-grained molecular and mesoscale models and simulation methods capable of simulating the assembly of millions of organic conducting molecules and other molecular components into nanowires, crossbars, and other organized patterns.

    3. Mathematical modeling and computer simulation of processes in energy systems

      SciTech Connect (OSTI)

      Hanjalic, K.C. )

      1990-01-01

      This book is divided into the following chapters. Modeling techniques and tools (fundamental concepts of modeling); 2. Fluid flow, heat and mass transfer, chemical reactions, and combustion; 3. Processes in energy equipment and plant components (boilers, steam and gas turbines, IC engines, heat exchangers, pumps and compressors, nuclear reactors, steam generators and separators, energy transport equipment, energy convertors, etc.); 4. New thermal energy conversion technologies (MHD, coal gasification and liquefaction fluidized-bed combustion, pulse-combustors, multistage combustion, etc.); 5. Combined cycles and plants, cogeneration; 6. Dynamics of energy systems and their components; 7. Integrated approach to energy systems modeling, and 8. Application of modeling in energy expert systems.

    4. Modeling-Computer Simulations (Walker, Et Al., 2005) | Open Energy...

      Open Energy Info (EERE)

      occurrence model for geothermal systems based on fundamental geologic data. References J. D. Walker, A. E. Sabin, J. R. Unruh, J. Combs, F. C. Monastero (2005) Development Of...

    5. Modeling-Computer Simulations At Kilauea East Rift Geothermal...

      Open Energy Info (EERE)

      importance of water convection for distributing heat in the East Rift Zone. References Albert J. Rudman, David Epp (1983) Conduction Models Of The Temperature Distribution In The...

    6. An Approach to Integrate a Space-Time GIS Data Model with High Performance Computers

      SciTech Connect (OSTI)

      Wang, Dali; Zhao, Ziliang; Shaw, Shih-Lung

      2011-01-01

      In this paper, we describe an approach to integrate a Space-Time GIS data model on a high performance computing platform. The Space-Time GIS data model has been developed on a desktop computing environment. We use the Space-Time GIS data model to generate GIS module, which organizes a series of remote sensing data. We are in the process of porting the GIS module into an HPC environment, in which the GIS modules handle large dataset directly via parallel file system. Although it is an ongoing project, authors hope this effort can inspire further discussions on the integration of GIS on high performance computing platforms.

    7. Modeling and Analysis of a Lunar Space Reactor with the Computer Code

      Office of Scientific and Technical Information (OSTI)

      RELAP5-3D/ATHENA (Conference) | SciTech Connect Conference: Modeling and Analysis of a Lunar Space Reactor with the Computer Code RELAP5-3D/ATHENA Citation Details In-Document Search Title: Modeling and Analysis of a Lunar Space Reactor with the Computer Code RELAP5-3D/ATHENA The transient analysis 3-dimensional (3-D) computer code RELAP5-3D/ATHENA has been employed to model and analyze a space reactor of 180 kW(thermal), 40 kW (net, electrical) with eight Stirling engines (SEs). Each SE

    8. GEO3D - Three-Dimensional Computer Model of a Ground Source Heat Pump System

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

      James Menart

      2013-06-07

      This file is the setup file for the computer program GEO3D. GEO3D is a computer program written by Jim Menart to simulate vertical wells in conjunction with a heat pump for ground source heat pump (GSHP) systems. This is a very detailed three-dimensional computer model. This program produces detailed heat transfer and temperature field information for a vertical GSHP system.

    9. Demonstrating the improvement of predictive maturity of a computational model

      SciTech Connect (OSTI)

      Hemez, Francois M; Unal, Cetin; Atamturktur, Huriye S

      2010-01-01

      We demonstrate an improvement of predictive capability brought to a non-linear material model using a combination of test data, sensitivity analysis, uncertainty quantification, and calibration. A model that captures increasingly complicated phenomena, such as plasticity, temperature and strain rate effects, is analyzed. Predictive maturity is defined, here, as the accuracy of the model to predict multiple Hopkinson bar experiments. A statistical discrepancy quantifies the systematic disagreement (bias) between measurements and predictions. Our hypothesis is that improving the predictive capability of a model should translate into better agreement between measurements and predictions. This agreement, in turn, should lead to a smaller discrepancy. We have recently proposed to use discrepancy and coverage, that is, the extent to which the physical experiments used for calibration populate the regime of applicability of the model, as basis to define a Predictive Maturity Index (PMI). It was shown that predictive maturity could be improved when additional physical tests are made available to increase coverage of the regime of applicability. This contribution illustrates how the PMI changes as 'better' physics are implemented in the model. The application is the non-linear Preston-Tonks-Wallace (PTW) strength model applied to Beryllium metal. We demonstrate that our framework tracks the evolution of maturity of the PTW model. Robustness of the PMI with respect to the selection of coefficients needed in its definition is also studied.

    10. Computer support to run models of the atmosphere. Final report

      SciTech Connect (OSTI)

      Fung, I.

      1996-08-30

      This research is focused on a better quantification of the variations in CO{sub 2} exchanges between the atmosphere and biosphere and the factors responsible for these exchangers. The principal approach is to infer the variations in the exchanges from variations in the atmospheric CO{sub 2} distribution. The principal tool involves using a global three-dimensional tracer transport model to advect and convect CO{sub 2} in the atmosphere. The tracer model the authors used was developed at the Goddard institute for Space Studies (GISS) and is derived from the GISS atmospheric general circulation model. A special run of the GCM is made to save high-frequency winds and mixing statistics for the tracer model.

    11. Modeling-Computer Simulations (Gritto & Majer) | Open Energy...

      Open Energy Info (EERE)

      are shown in Figure 1. The parameters of the fault were modeled after Coates and Schoenberg (1995), where the orientation of the fault relative to the finite-difference grid...

    12. Cielo Computational Environment Usage Model With Mappings to...

      Office of Scientific and Technical Information (OSTI)

      This document describes specific capabilities, tools, and procedures to support both local and remote users. The model is focused on the needs of the ASC user working in the secure ...

    13. Inductively coupled plasma-atomic emission spectroscopy: a computer controlled, scanning monochromator system for the rapid determination of the elements

      SciTech Connect (OSTI)

      Floyd, M.A.

      1980-03-01

      A computer controlled, scanning monochromator system specifically designed for the rapid, sequential determination of the elements is described. The monochromator is combined with an inductively coupled plasma excitation source so that elements at major, minor, trace, and ultratrace levels may be determined, in sequence, without changing experimental parameters other than the spectral line observed. A number of distinctive features not found in previously described versions are incorporated into the system here described. Performance characteristics of the entire system and several analytical applications are discussed.

    14. A computationally efficient parallel Levenberg-Marquardt algorithm for highly parameterized inverse model analyses

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

      Lin, Youzuo; O'Malley, Daniel; Vesselinov, Velimir V.

      2016-08-19

      Inverse modeling seeks model parameters given a set of observations. However, for practical problems because the number of measurements is often large and the model parameters are also numerous, conventional methods for inverse modeling can be computationally expensive. We have developed a new, computationally-efficient parallel Levenberg-Marquardt method for solving inverse modeling problems with a highly parameterized model space. Levenberg-Marquardt methods require the solution of a linear system of equations which can be prohibitively expensive to compute for moderate to large-scale problems. Our novel method projects the original linear problem down to a Krylov subspace, such that the dimensionality of themore » problem can be significantly reduced. Furthermore, we store the Krylov subspace computed when using the first damping parameter and recycle the subspace for the subsequent damping parameters. The efficiency of our new inverse modeling algorithm is significantly improved using these computational techniques. We apply this new inverse modeling method to invert for random transmissivity fields in 2D and a random hydraulic conductivity field in 3D. Our algorithm is fast enough to solve for the distributed model parameters (transmissivity) in the model domain. The algorithm is coded in Julia and implemented in the MADS computational framework (http://mads.lanl.gov). By comparing with Levenberg-Marquardt methods using standard linear inversion techniques such as QR or SVD methods, our Levenberg-Marquardt method yields a speed-up ratio on the order of ~101 to ~102 in a multi-core computational environment. Furthermore, our new inverse modeling method is a powerful tool for characterizing subsurface heterogeneity for moderate- to large-scale problems.« less

    15. FINITE ELEMENT MODELS FOR COMPUTING SEISMIC INDUCED SOIL PRESSURES ON DEEPLY EMBEDDED NUCLEAR POWER PLANT STRUCTURES.

      SciTech Connect (OSTI)

      XU, J.; COSTANTINO, C.; HOFMAYER, C.

      2006-06-26

      PAPER DISCUSSES COMPUTATIONS OF SEISMIC INDUCED SOIL PRESSURES USING FINITE ELEMENT MODELS FOR DEEPLY EMBEDDED AND OR BURIED STIFF STRUCTURES SUCH AS THOSE APPEARING IN THE CONCEPTUAL DESIGNS OF STRUCTURES FOR ADVANCED REACTORS.

    16. Theoretical and computer models of detonation in solid explosives

      SciTech Connect (OSTI)

      Tarver, C.M.; Urtiew, P.A.

      1997-10-01

      Recent experimental and theoretical advances in understanding energy transfer and chemical kinetics have led to improved models of detonation waves in solid explosives. The Nonequilibrium Zeldovich - von Neumann - Doring (NEZND) model is supported by picosecond laser experiments and molecular dynamics simulations of the multiphonon up-pumping and internal vibrational energy redistribution (IVR) processes by which the unreacted explosive molecules are excited to the transition state(s) preceding reaction behind the leading shock front(s). High temperature, high density transition state theory calculates the induction times measured by laser interferometric techniques. Exothermic chain reactions form product gases in highly excited vibrational states, which have been demonstrated to rapidly equilibrate via supercollisions. Embedded gauge and Fabry-Perot techniques measure the rates of reaction product expansion as thermal and chemical equilibrium is approached. Detonation reaction zone lengths in carbon-rich condensed phase explosives depend on the relatively slow formation of solid graphite or diamond. The Ignition and Growth reactive flow model based on pressure dependent reaction rates and Jones-Wilkins-Lee (JWL) equations of state has reproduced this nanosecond time resolved experimental data and thus has yielded accurate average reaction zone descriptions in one-, two- and three- dimensional hydrodynamic code calculations. The next generation reactive flow model requires improved equations of state and temperature dependent chemical kinetics. Such a model is being developed for the ALE3D hydrodynamic code, in which heat transfer and Arrhenius kinetics are intimately linked to the hydrodynamics.

    17. Towards a Computational Model of a Methane Producing Archaeum

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

      Peterson, Joseph R.; Labhsetwar, Piyush; Ellermeier, Jeremy R.; Kohler, Petra R. A.; Jain, Ankur; Ha, Taekjip; Metcalf, William W.; Luthey-Schulten, Zaida

      2014-01-01

      Progress towards a complete model of the methanogenic archaeum Methanosarcina acetivorans is reported. We characterized size distribution of the cells using differential interference contrast microscopy, finding them to be ellipsoidal with mean length and width of 2.9  μ m and 2.3  μ m, respectively, when grown on methanol and 30% smaller when grown on acetate. We used the single molecule pull down (SiMPull) technique to measure average copy number of the Mcr complex and ribosomes. A kinetic model for the methanogenesis pathways based on biochemical studies and recent metabolic reconstructions for several related methanogens is presented. In this model,more » 26 reactions in the methanogenesis pathways are coupled to a cell mass production reaction that updates enzyme concentrations. RNA expression data (RNA-seq) measured for cell cultures grown on acetate and methanol is used to estimate relative protein production per mole of ATP consumed. The model captures the experimentally observed methane production rates for cells growing on methanol and is most sensitive to the number of methyl-coenzyme-M reductase (Mcr) and methyl-tetrahydromethanopterin:coenzyme-M methyltransferase (Mtr) proteins. A draft transcriptional regulation network based on known interactions is proposed which we intend to integrate with the kinetic model to allow dynamic regulation.« less

    18. Computer model for characterizing, screening, and optimizing electrolyte systems

      SciTech Connect (OSTI)

      Gering, Kevin L.

      2015-06-15

      Electrolyte systems in contemporary batteries are tasked with operating under increasing performance requirements. All battery operation is in some way tied to the electrolyte and how it interacts with various regions within the cell environment. Seeing the electrolyte plays a crucial role in battery performance and longevity, it is imperative that accurate, physics-based models be developed that will characterize key electrolyte properties while keeping pace with the increasing complexity of these liquid systems. Advanced models are needed since laboratory measurements require significant resources to carry out for even a modest experimental matrix. The Advanced Electrolyte Model (AEM) developed at the INL is a proven capability designed to explore molecular-to-macroscale level aspects of electrolyte behavior, and can be used to drastically reduce the time required to characterize and optimize electrolytes. Although it is applied most frequently to lithium-ion battery systems, it is general in its theory and can be used toward numerous other targets and intended applications. This capability is unique, powerful, relevant to present and future electrolyte development, and without peer. It redefines electrolyte modeling for highly-complex contemporary systems, wherein significant steps have been taken to capture the reality of electrolyte behavior in the electrochemical cell environment. This capability can have a very positive impact on accelerating domestic battery development to support aggressive vehicle and energy goals in the 21st century.

    19. ONSET OF CHAOS IN A MODEL OF QUANTUM COMPUTATION (Conference) | SciTech

      Office of Scientific and Technical Information (OSTI)

      Connect Conference: ONSET OF CHAOS IN A MODEL OF QUANTUM COMPUTATION Citation Details In-Document Search Title: ONSET OF CHAOS IN A MODEL OF QUANTUM COMPUTATION Recently, the question of a relevance of the so-called quantum chaos has been raised in applications to quantum computation [2,3]. Indeed, according to the general approach to closed systems of finite number of interacting Fermi-particles (see, e.g. [4,5]), with an increase of an interaction between qubits a kind of chaos is expected

    20. CASTING DEFECT MODELING IN AN INTEGRATED COMPUTATIONAL MATERIALS ENGINEERING APPROACH

      SciTech Connect (OSTI)

      Sabau, Adrian S

      2015-01-01

      To accelerate the introduction of new cast alloys, the simultaneous modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. The required models related to casting defects, such as microporosity and hot tears, are reviewed. Three aluminum alloys are considered A356, 356 and 319. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Examples are given for predicting microporosity defects and microstructure distribution for a plate casting. Models to predict fatigue life and yield stress are briefly highlighted here for the sake of completion and to illustrate how the length scales of the microstructure features as well as porosity defects are taken into account for modeling the mechanical properties. Thus, the data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the component. ACKNOWLEDGEMENTS This work was performed under a Cooperative Research and Development Agreement (CRADA) with the Nemak Inc., and Chrysler Co. for the project "High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines. The author would also like to thank Amit Shyam for reviewing the paper and Andres Rodriguez of Nemak Inc. Research sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, as part of the Propulsion Materials Program under contract DE-AC05-00OR22725 with UT-Battelle, LLC. Part of this research was conducted through the Oak Ridge National Laboratory's High Temperature Materials Laboratory User Program, which is sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.

    1. Computational models for the berry phase in semiconductor quantum dots

      SciTech Connect (OSTI)

      Prabhakar, S. Melnik, R. V. N.; Sebetci, A.

      2014-10-06

      By developing a new model and its finite element implementation, we analyze the Berry phase low-dimensional semiconductor nanostructures, focusing on quantum dots (QDs). In particular, we solve the Schrdinger equation and investigate the evolution of the spin dynamics during the adiabatic transport of the QDs in the 2D plane along circular trajectory. Based on this study, we reveal that the Berry phase is highly sensitive to the Rashba and Dresselhaus spin-orbit lengths.

    2. Accelerated Climate Modeling for Energy | Argonne Leadership Computing

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

      Facility a Category 5 hurricane simulated by the CESM at 13 km resolution An example of a Category 5 hurricane simulated by the CESM at 13 km resolution. Precipitable water (gray scale) shows the detailed dynamical structure in the flow. Strong precipitation is overlaid in red. High resolution is necessary to simulate reasonable numbers of tropical cyclones including Category 4 and 5 storms. Credit: Alan Scott and Mark Taylor, Sandia National Laboratories Accelerated Climate Modeling for

    3. Accelerated Climate Modeling for Energy | Argonne Leadership Computing

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

      Facility An example of a Category 5 hurricane simulated by the CESM at 13 km resolution An example of a Category 5 hurricane simulated by the CESM at 13 km resolution. Precipitable water (gray scale) shows the detailed dynamical structure in the flow. Strong precipitation is overlaid in red. High resolution is necessary to simulate reasonable numbers of tropical cyclones including Category 4 and 5 storms. Alan Scott and Mark Taylor, Sandia National Laboratories Accelerated Climate Modeling

    4. Computer modeling of a CFB (circulating fluidized bed) gasifier

      SciTech Connect (OSTI)

      Gidaspow, D.; Ding, J.

      1990-06-01

      The overall objective of this investigation is to develop experimentally verified models for circulating fluidized bed (CFB) combustors. This report presents an extension of our cold flow modeling of a CFB given in our first quarterly report of this project and published in Numerical Methods for Multiphase Flows'' edited by I. Celik, D. Hughes, C. T. Crowe and D. Lankford, FED-Vol.91, American Society of Mechanical Engineering, pp47--56 (1990). The title of the paper is Multiphase Navier-Stokes Equation Solver'' by D. Gidaspow, J. Ding and U.K. Jayaswal. To the two dimensional code described in the above paper we added the energy equations and the conservation of species equations to describe a synthesis gas from char producer. Under the simulation conditions the injected oxygen reacted near the inlet. The solid-gas mixing was sufficiently rapid that no undesirable hot spots were produced. This simulation illustrates the code's capability to model CFB reactors. 15 refs., 20 figs.

    5. Computer model for characterizing, screening, and optimizing electrolyte systems

      Energy Science and Technology Software Center (OSTI)

      2015-06-15

      Electrolyte systems in contemporary batteries are tasked with operating under increasing performance requirements. All battery operation is in some way tied to the electrolyte and how it interacts with various regions within the cell environment. Seeing the electrolyte plays a crucial role in battery performance and longevity, it is imperative that accurate, physics-based models be developed that will characterize key electrolyte properties while keeping pace with the increasing complexity of these liquid systems. Advanced modelsmore » are needed since laboratory measurements require significant resources to carry out for even a modest experimental matrix. The Advanced Electrolyte Model (AEM) developed at the INL is a proven capability designed to explore molecular-to-macroscale level aspects of electrolyte behavior, and can be used to drastically reduce the time required to characterize and optimize electrolytes. Although it is applied most frequently to lithium-ion battery systems, it is general in its theory and can be used toward numerous other targets and intended applications. This capability is unique, powerful, relevant to present and future electrolyte development, and without peer. It redefines electrolyte modeling for highly-complex contemporary systems, wherein significant steps have been taken to capture the reality of electrolyte behavior in the electrochemical cell environment. This capability can have a very positive impact on accelerating domestic battery development to support aggressive vehicle and energy goals in the 21st century.« less

    6. Computer-Aided Construction of Combustion Chemistry Models

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

      Constructing Accurate Combustion Chemistry Models: Butanols William H. Green & Michael Harper MIT Dept. of Chem. Eng. CEFRC Annual Meeting, Sept. 2010 The people who did this work: Dr. C. Franklin Goldsmith Greg Magoon Shamel Merchant Dr. Sumathy Raman Dr. Sandeep Sharma Prof. Kevin Van Geem Steven Pyl We are also grateful to: Joshua Allen Prof. Paul Barton Dr. Stephen Klippenstein Prof. Guy Marin Jeffrey Mo Dr. S-A Seyed-Reihani Dr. Richard West & MANY CEFRC MEMBERS One of Our Project's

    7. Computational Human Performance Modeling For Alarm System Design

      SciTech Connect (OSTI)

      Jacques Hugo

      2012-07-01

      The introduction of new technologies like adaptive automation systems and advanced alarms processing and presentation techniques in nuclear power plants is already having an impact on the safety and effectiveness of plant operations and also the role of the control room operator. This impact is expected to escalate dramatically as more and more nuclear power utilities embark on upgrade projects in order to extend the lifetime of their plants. One of the most visible impacts in control rooms will be the need to replace aging alarm systems. Because most of these alarm systems use obsolete technologies, the methods, techniques and tools that were used to design the previous generation of alarm system designs are no longer effective and need to be updated. The same applies to the need to analyze and redefine operators alarm handling tasks. In the past, methods for analyzing human tasks and workload have relied on crude, paper-based methods that often lacked traceability. New approaches are needed to allow analysts to model and represent the new concepts of alarm operation and human-system interaction. State-of-the-art task simulation tools are now available that offer a cost-effective and efficient method for examining the effect of operator performance in different conditions and operational scenarios. A discrete event simulation system was used by human factors researchers at the Idaho National Laboratory to develop a generic alarm handling model to examine the effect of operator performance with simulated modern alarm system. It allowed analysts to evaluate alarm generation patterns as well as critical task times and human workload predicted by the system.

    8. Load determination for long cable bolt support using computer aided bolt load estimation (CABLE) program

      SciTech Connect (OSTI)

      Bawden, W.F.; Moosavi, M.; Hyett, A.J.

      1996-12-01

      In this paper a numerical formulation is presented for determination of the axial load along a cable bolt for a prescribed distribution of rock mass displacement. Results using the program CABLE indicate that during excavation, the load distribution that develops along an untensioned fully grouted cable bolt depends on three main factors: (i) the properties of the cable itself, (ii) the shear force that develops due to bond at the cable-grout interface (i.e. bond stiffness), and (iii) the distribution of rock mass displacement along the cable bolt length. in general, the effect of low modulus rock and mining induced stress decreases in reducing bond strength as determined from short embedment length tests, is reflected in the development of axial loads significantly less than the ultimate tensile capacity even for long cable bolts. However, the load distribution is also dependent on the deformation distribution in the reinforced rock mass. Higher cable bolt loads will be developed for a rock mass that behaves as a discontinuum, with deformation concentrated on a few fractures, than for one which behaves as a continuum, either due to a total lack of fractures or a very high fracture density. This result suggests that the stiffness of a fully grouted cable bolt is not simply a characteristic of the bolt and grout used, but also of the deformation behavior of the ground. In other words, the same combination of bolt and grout will be stiffer if the rock behaves as a discontinuum than if it behaves as a continuum. This paper also explains the laboratory test program used to determine the constitutive behavior of the Garford bulb and Nutcase cables bolts. Details of the test setup as well as the obtained results are summarized and discussed.

    9. R&D for computational cognitive and social models : foundations for model evaluation through verification and validation (final LDRD report).

      SciTech Connect (OSTI)

      Slepoy, Alexander; Mitchell, Scott A.; Backus, George A.; McNamara, Laura A.; Trucano, Timothy Guy

      2008-09-01

      Sandia National Laboratories is investing in projects that aim to develop computational modeling and simulation applications that explore human cognitive and social phenomena. While some of these modeling and simulation projects are explicitly research oriented, others are intended to support or provide insight for people involved in high consequence decision-making. This raises the issue of how to evaluate computational modeling and simulation applications in both research and applied settings where human behavior is the focus of the model: when is a simulation 'good enough' for the goals its designers want to achieve? In this report, we discuss two years' worth of review and assessment of the ASC program's approach to computational model verification and validation, uncertainty quantification, and decision making. We present a framework that extends the principles of the ASC approach into the area of computational social and cognitive modeling and simulation. In doing so, we argue that the potential for evaluation is a function of how the modeling and simulation software will be used in a particular setting. In making this argument, we move from strict, engineering and physics oriented approaches to V&V to a broader project of model evaluation, which asserts that the systematic, rigorous, and transparent accumulation of evidence about a model's performance under conditions of uncertainty is a reasonable and necessary goal for model evaluation, regardless of discipline. How to achieve the accumulation of evidence in areas outside physics and engineering is a significant research challenge, but one that requires addressing as modeling and simulation tools move out of research laboratories and into the hands of decision makers. This report provides an assessment of our thinking on ASC Verification and Validation, and argues for further extending V&V research in the physical and engineering sciences toward a broader program of model evaluation in situations of high

    10. Noise analysis of genome-scale protein synthesis using a discrete computational model of translation

      SciTech Connect (OSTI)

      Racle, Julien; Hatzimanikatis, Vassily; Stefaniuk, Adam Jan

      2015-07-28

      Noise in genetic networks has been the subject of extensive experimental and computational studies. However, very few of these studies have considered noise properties using mechanistic models that account for the discrete movement of ribosomes and RNA polymerases along their corresponding templates (messenger RNA (mRNA) and DNA). The large size of these systems, which scales with the number of genes, mRNA copies, codons per mRNA, and ribosomes, is responsible for some of the challenges. Additionally, one should be able to describe the dynamics of ribosome exchange between the free ribosome pool and those bound to mRNAs, as well as how mRNA species compete for ribosomes. We developed an efficient algorithm for stochastic simulations that addresses these issues and used it to study the contribution and trade-offs of noise to translation properties (rates, time delays, and rate-limiting steps). The algorithm scales linearly with the number of mRNA copies, which allowed us to study the importance of genome-scale competition between mRNAs for the same ribosomes. We determined that noise is minimized under conditions maximizing the specific synthesis rate. Moreover, sensitivity analysis of the stochastic system revealed the importance of the elongation rate in the resultant noise, whereas the translation initiation rate constant was more closely related to the average protein synthesis rate. We observed significant differences between our results and the noise properties of the most commonly used translation models. Overall, our studies demonstrate that the use of full mechanistic models is essential for the study of noise in translation and transcription.

    11. A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus

      SciTech Connect (OSTI)

      Raustad, Richard A.

      2013-01-01

      This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

    12. Techno-Economic Modeling - Building New Battery Systems on the Computer -

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

      Joint Center for Energy Storage Research October 22, 2015, Accomplishments Techno-Economic Modeling - Building New Battery Systems on the Computer JCESR is applying techno-economic models to project the performance and cost of a wide array of promising new battery systems before they are prototyped. The results from techno-economic modeling establish performance "floors" for discovery science teams looking for new anodes, cathodes, and electrolytes for a beyond lithium-ion battery,

    13. Verification of a VRF Heat Pump Computer Model in EnergyPlus

      SciTech Connect (OSTI)

      Nigusse, Bereket; Raustad, Richard

      2013-06-01

      This paper provides verification results of the EnergyPlus variable refrigerant flow (VRF) heat pump computer model using manufacturer's performance data. The paper provides an overview of the VRF model, presents the verification methodology, and discusses the results. The verification provides quantitative comparison of full and part-load performance to manufacturer's data in cooling-only and heating-only modes of operation. The VRF heat pump computer model uses dual range bi-quadratic performance curves to represent capacity and Energy Input Ratio (EIR) as a function of indoor and outdoor air temperatures, and dual range quadratic performance curves as a function of part-load-ratio for modeling part-load performance. These performance curves are generated directly from manufacturer's published performance data. The verification compared the simulation output directly to manufacturer's performance data, and found that the dual range equation fit VRF heat pump computer model predicts the manufacturer's performance data very well over a wide range of indoor and outdoor temperatures and part-load conditions. The predicted capacity and electric power deviations are comparbale to equation-fit HVAC computer models commonly used for packaged and split unitary HVAC equipment.

    14. A Hybrid MPI/OpenMP Approach for Parallel Groundwater Model Calibration on Multicore Computers

      SciTech Connect (OSTI)

      Tang, Guoping; D'Azevedo, Ed F; Zhang, Fan; Parker, Jack C.; Watson, David B; Jardine, Philip M

      2010-01-01

      Groundwater model calibration is becoming increasingly computationally time intensive. We describe a hybrid MPI/OpenMP approach to exploit two levels of parallelism in software and hardware to reduce calibration time on multicore computers with minimal parallelization effort. At first, HydroGeoChem 5.0 (HGC5) is parallelized using OpenMP for a uranium transport model with over a hundred species involving nearly a hundred reactions, and a field scale coupled flow and transport model. In the first application, a single parallelizable loop is identified to consume over 97% of the total computational time. With a few lines of OpenMP compiler directives inserted into the code, the computational time reduces about ten times on a compute node with 16 cores. The performance is further improved by selectively parallelizing a few more loops. For the field scale application, parallelizable loops in 15 of the 174 subroutines in HGC5 are identified to take more than 99% of the execution time. By adding the preconditioned conjugate gradient solver and BICGSTAB, and using a coloring scheme to separate the elements, nodes, and boundary sides, the subroutines for finite element assembly, soil property update, and boundary condition application are parallelized, resulting in a speedup of about 10 on a 16-core compute node. The Levenberg-Marquardt (LM) algorithm is added into HGC5 with the Jacobian calculation and lambda search parallelized using MPI. With this hybrid approach, compute nodes at the number of adjustable parameters (when the forward difference is used for Jacobian approximation), or twice that number (if the center difference is used), are used to reduce the calibration time from days and weeks to a few hours for the two applications. This approach can be extended to global optimization scheme and Monte Carol analysis where thousands of compute nodes can be efficiently utilized.

    15. Computing Videos

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

      Computing Videos Computing

    16. COMPARATIVE COMPUTATIONAL MODELING OF AIRFLOWS AND VAPOR DOSIMETY IN THE RESPIRATORY TRACTS OF RAT, MONKEY, AND HUMAN

      SciTech Connect (OSTI)

      Corley, Richard A.; Kabilan, Senthil; Kuprat, Andrew P.; Carson, James P.; Minard, Kevin R.; Jacob, Rick E.; Timchalk, Charles; Glenny, Robb W.; Pipavath, Sudhaker; Cox, Timothy C.; Wallis, Chris; Larson, Richard; Fanucchi, M.; Postlewait, Ed; Einstein, Daniel R.

      2012-07-01

      Coupling computational fluid dynamics (CFD) with physiologically based pharmacokinetic (PBPK) models is useful for predicting site-specific dosimetry of airborne materials in the respiratory tract and elucidating the importance of species differences in anatomy, physiology, and breathing patterns. Historically, these models were limited to discrete regions of the respiratory system. CFD/PBPK models have now been developed for the rat, monkey, and human that encompass airways from the nose or mouth to the lung. A PBPK model previously developed to describe acrolein uptake in nasal tissues was adapted to the extended airway models as an example application. Model parameters for each anatomic region were obtained from the literature, measured directly, or estimated from published data. Airflow and site-specific acrolein uptake patterns were determined under steadystate inhalation conditions to provide direct comparisons with prior data and nasalonly simulations. Results confirmed that regional uptake was dependent upon airflow rates and acrolein concentrations with nasal extraction efficiencies predicted to be greatest in the rat, followed by the monkey, then the human. For human oral-breathing simulations, acrolein uptake rates in oropharyngeal and laryngeal tissues were comparable to nasal tissues following nasal breathing under the same exposure conditions. For both breathing modes, higher uptake rates were predicted for lower tracheo-bronchial tissues of humans than either the rat or monkey. These extended airway models provide a unique foundation for comparing dosimetry across a significantly more extensive range of conducting airways in the rat, monkey, and human than prior CFD models.

    17. Modeling of BWR core meltdown accidents - for application in the MELRPI. MOD2 computer code

      SciTech Connect (OSTI)

      Koh, B R; Kim, S H; Taleyarkhan, R P; Podowski, M Z; Lahey, Jr, R T

      1985-04-01

      This report summarizes improvements and modifications made in the MELRPI computer code. A major difference between this new, updated version of the code, called MELRPI.MOD2, and the one reported previously, concerns the inclusion of a model for the BWR emergency core cooling systems (ECCS). This model and its computer implementation, the ECCRPI subroutine, account for various emergency injection modes, for both intact and rubblized geometries. Other changes to MELRPI deal with an improved model for canister wall oxidation, rubble bed modeling, and numerical integration of system equations. A complete documentation of the entire MELRPI.MOD2 code is also given, including an input guide, list of subroutines, sample input/output and program listing.

    18. Once-through CANDU reactor models for the ORIGEN2 computer code

      SciTech Connect (OSTI)

      Croff, A.G.; Bjerke, M.A.

      1980-11-01

      Reactor physics calculations have led to the development of two CANDU reactor models for the ORIGEN2 computer code. The model CANDUs are based on (1) the existing once-through fuel cycle with feed comprised of natural uranium and (2) a projected slightly enriched (1.2 wt % /sup 235/U) fuel cycle. The reactor models are based on cross sections taken directly from the reactor physics codes. Descriptions of the reactor models, as well as values for the ORIGEN2 flux parameters THERM, RES, and FAST, are given.

    19. DOE Issues Funding Opportunity for Advanced Computational and Modeling Research for the Electric Power System

      Broader source: Energy.gov [DOE]

      The objective of this Funding Opportunity Announcement (FOA) is to leverage scientific advancements in mathematics and computation for application to power system models and software tools, with the long-term goal of enabling real-time protection and control based on wide-area sensor measurements.

    20. Application of a computational glass model to the shock response of soda-lime glass

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

      Gorfain, Joshua E.; Key, Christopher T.; Alexander, C. Scott

      2016-04-20

      This article details the implementation and application of the glass-specific computational constitutive model by Holmquist and Johnson [1] to simulate the dynamic response of soda-lime glass under high rate and high pressure shock conditions. The predictive capabilities of this model are assessed through comparison of experimental data with numerical results from computations using the CTH shock physics code. The formulation of this glass model is reviewed in the context of its implementation within CTH. Using a variety of experimental data compiled from the open literature, a complete parameterization of the model describing the observed behavior of soda-lime glass is developed.more » Simulation results using the calibrated soda-lime glass model are compared to flyer plate and Taylor rod impact experimental data covering a range of impact and failure conditions spanning an order of magnitude in velocity and pressure. In conclusion, the complex behavior observed in the experimental testing is captured well in the computations, demonstrating the capability of the glass model within CTH.« less

    1. Technical Review of the CENWP Computational Fluid Dynamics Model of the John Day Dam Forebay

      SciTech Connect (OSTI)

      Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.

      2010-12-01

      The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWP's CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequately configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.

    2. Determination

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

      Determinants of Household Use of Selected Energy Star Appliances May 2016 Independent Statistics & Analysis www.eia.gov U.S. Department of Energy Washington, DC 20585 U.S. Energy Information Administration | Determinants of Household Use of Selected Energy Star Appliances i This report was prepared by the U.S. Energy Information Administration (EIA), the statistical and analytical agency within the U.S. Department of Energy. By law, EIA's data, analyses, and forecasts are independent of

    3. Computational method and system for modeling, analyzing, and optimizing DNA amplification and synthesis

      DOE Patents [OSTI]

      Vandersall, Jennifer A.; Gardner, Shea N.; Clague, David S.

      2010-05-04

      A computational method and computer-based system of modeling DNA synthesis for the design and interpretation of PCR amplification, parallel DNA synthesis, and microarray chip analysis. The method and system include modules that address the bioinformatics, kinetics, and thermodynamics of DNA amplification and synthesis. Specifically, the steps of DNA selection, as well as the kinetics and thermodynamics of DNA hybridization and extensions, are addressed, which enable the optimization of the processing and the prediction of the products as a function of DNA sequence, mixing protocol, time, temperature and concentration of species.

    4. Vehicle Technologies Office Merit Review 2014: Significant Enhancement of Computational Efficiency in Nonlinear Multiscale Battery Model for Computer Aided Engineering

      Broader source: Energy.gov [DOE]

      Presentation given by NREL at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about significant enhancement of computational...

    5. Computer modeling of electromagnetic edge containment in twin-roll casting

      SciTech Connect (OSTI)

      Chang, F.C.; Turner, L.R.; Hull, J.R.; Wang, Y.H.; Blazek, K.E.

      1998-07-01

      This paper presents modeling studies of magnetohydrodynamics (MHD) analysis in twin-roll casting. Argonne National Laboratory (ANL) and Inland Steel Company have worked together to develop a 3-D computer model that can predict eddy currents, fluid flows, and liquid metal containment for an electromagnetic (EM) edge containment device. This mathematical model can greatly shorten casting research on the use of EM fields for liquid metal containment and control. It can also optimize the existing casting processes and minimize expensive, time-consuming full-scale testing. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in EM edge dams designed at Inland Steel for twin-roll casting. Numerical simulation was performed by coupling a three-dimensional (3-D) finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve Maxwell`s equations, Ohm`s law, Navier-Stokes equations, and transport equations of turbulence flow in a casting process that uses EM fields. ELEKTRA is able to predict the eddy-current distribution and electromagnetic forces in complex geometry. CaPS-EM is capable of modeling fluid flows with free-surfaces and dynamic rollers. The computed 3-D magnetic fields and induced eddy currents in ELEKTRA are used as input to flow-field computations in CaPS-EM. Results of the numerical simulation compared well with measurements obtained from both static and dynamic tests.

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

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

      Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

      2014-11-01

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

    7. Models the Electromagnetic Response of a 3D Distribution using MP COMPUTERS

      Energy Science and Technology Software Center (OSTI)

      1999-05-01

      EM3D models the electromagnetic response of a 3D distribution of conductivity, dielectric permittivity and magnetic permeability within the earth for geophysical applications using massively parallel computers. The simulations are carried out in the frequency domain for either electric or magnetic sources for either scattered or total filed formulations of Maxwell''s equations. The solution is based on the method of finite differences and includes absorbing boundary conditions so that responses can be modeled up into themore » radar range where wave propagation is dominant. Recent upgrades in the software include the incorporation of finite size sources, that in addition to dipolar source fields, and a low induction number preconditioner that can significantly reduce computational run times. A graphical user interface (GUI) is bundled with the software so that complicated 3D models can be easily constructed and simulated with the software. The GUI also allows for plotting of the output.« less

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

      SciTech Connect (OSTI)

      Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

      2014-11-01

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

    9. Use of ARM observations and numerical models to determine radiative...

      Office of Scientific and Technical Information (OSTI)

      We investigated whether the West African anvil clouds connected with squall line MCSs passing over the Niamey ARM site could be simulated in a numerical model by comparing the ...

    10. Sodium fast reactor gaps analysis of computer codes and models for accident analysis and reactor safety.

      SciTech Connect (OSTI)

      Carbajo, Juan; Jeong, Hae-Yong; Wigeland, Roald; Corradini, Michael; Schmidt, Rodney Cannon; Thomas, Justin; Wei, Tom; Sofu, Tanju; Ludewig, Hans; Tobita, Yoshiharu; Ohshima, Hiroyuki; Serre, Frederic

      2011-06-01

      This report summarizes the results of an expert-opinion elicitation activity designed to qualitatively assess the status and capabilities of currently available computer codes and models for accident analysis and reactor safety calculations of advanced sodium fast reactors, and identify important gaps. The twelve-member panel consisted of representatives from five U.S. National Laboratories (SNL, ANL, INL, ORNL, and BNL), the University of Wisconsin, the KAERI, the JAEA, and the CEA. The major portion of this elicitation activity occurred during a two-day meeting held on Aug. 10-11, 2010 at Argonne National Laboratory. There were two primary objectives of this work: (1) Identify computer codes currently available for SFR accident analysis and reactor safety calculations; and (2) Assess the status and capability of current US computer codes to adequately model the required accident scenarios and associated phenomena, and identify important gaps. During the review, panel members identified over 60 computer codes that are currently available in the international community to perform different aspects of SFR safety analysis for various event scenarios and accident categories. A brief description of each of these codes together with references (when available) is provided. An adaptation of the Predictive Capability Maturity Model (PCMM) for computational modeling and simulation is described for use in this work. The panel's assessment of the available US codes is presented in the form of nine tables, organized into groups of three for each of three risk categories considered: anticipated operational occurrences (AOOs), design basis accidents (DBA), and beyond design basis accidents (BDBA). A set of summary conclusions are drawn from the results obtained. At the highest level, the panel judged that current US code capabilities are adequate for licensing given reasonable margins, but expressed concern that US code development activities had stagnated and that the

    11. Computing Sciences

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

      Division The Computational Research Division conducts research and development in mathematical modeling and simulation, algorithm design, data storage, management and...

    12. DualTrust: A Trust Management Model for Swarm-Based Autonomic Computing Systems

      SciTech Connect (OSTI)

      Maiden, Wendy M.

      2010-05-01

      Trust management techniques must be adapted to the unique needs of the application architectures and problem domains to which they are applied. For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, certain characteristics of the mobile agent ant swarm -- their lightweight, ephemeral nature and indirect communication -- make this adaptation especially challenging. This thesis looks at the trust issues and opportunities in swarm-based autonomic computing systems and finds that by monitoring the trustworthiness of the autonomic managers rather than the swarming sensors, the trust management problem becomes much more scalable and still serves to protect the swarm. After analyzing the applicability of trust management research as it has been applied to architectures with similar characteristics, this thesis specifies the required characteristics for trust management mechanisms used to monitor the trustworthiness of entities in a swarm-based autonomic computing system and describes a trust model that meets these requirements.

    13. On the Impact of Execution Models: A Case Study in Computational Chemistry

      SciTech Connect (OSTI)

      Chavarría-Miranda, Daniel; Halappanavar, Mahantesh; Krishnamoorthy, Sriram; Manzano Franco, Joseph B.; Vishnu, Abhinav; Hoisie, Adolfy

      2015-05-25

      Efficient utilization of high-performance computing (HPC) platforms is an important and complex problem. Execution models, abstract descriptions of the dynamic runtime behavior of the execution stack, have significant impact on the utilization of HPC systems. Using a computational chemistry kernel as a case study and a wide variety of execution models combined with load balancing techniques, we explore the impact of execution models on the utilization of an HPC system. We demonstrate a 50 percent improvement in performance by using work stealing relative to a more traditional static scheduling approach. We also use a novel semi-matching technique for load balancing that has comparable performance to a traditional hypergraph-based partitioning implementation, which is computationally expensive. Using this study, we found that execution model design choices and assumptions can limit critical optimizations such as global, dynamic load balancing and finding the correct balance between available work units and different system and runtime overheads. With the emergence of multi- and many-core architectures and the consequent growth in the complexity of HPC platforms, we believe that these lessons will be beneficial to researchers tuning diverse applications on modern HPC platforms, especially on emerging dynamic platforms with energy-induced performance variability.

    14. Superior model for fault tolerance computation in designing nano-sized circuit systems

      SciTech Connect (OSTI)

      Singh, N. S. S. Muthuvalu, M. S.; Asirvadam, V. S.

      2014-10-24

      As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines.

    15. Compare Energy Use in Variable Refrigerant Flow Heat Pumps Field Demonstration and Computer Model

      SciTech Connect (OSTI)

      Sharma, Chandan; Raustad, Richard

      2013-06-01

      Variable Refrigerant Flow (VRF) heat pumps are often regarded as energy efficient air-conditioning systems which offer electricity savings as well as reduction in peak electric demand while providing improved individual zone setpoint control. One of the key advantages of VRF systems is minimal duct losses which provide significant reduction in energy use and duct space. However, there is limited data available to show their actual performance in the field. Since VRF systems are increasingly gaining market share in the US, it is highly desirable to have more actual field performance data of these systems. An effort was made in this direction to monitor VRF system performance over an extended period of time in a US national lab test facility. Due to increasing demand by the energy modeling community, an empirical model to simulate VRF systems was implemented in the building simulation program EnergyPlus. This paper presents the comparison of energy consumption as measured in the national lab and as predicted by the program. For increased accuracy in the comparison, a customized weather file was created by using measured outdoor temperature and relative humidity at the test facility. Other inputs to the model included building construction, VRF system model based on lab measured performance, occupancy of the building, lighting/plug loads, and thermostat set-points etc. Infiltration model inputs were adjusted in the beginning to tune the computer model and then subsequent field measurements were compared to the simulation results. Differences between the computer model results and actual field measurements are discussed. The computer generated VRF performance closely resembled the field measurements.

    16. GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 1: Theory and Computational Model

      SciTech Connect (OSTI)

      Nichols, B.D.; Mueller, C.; Necker, G.A.; Travis, J.R.; Spore, J.W.; Lam, K.L.; Royl, P.; Redlinger, R.; Wilson, T.L.

      1998-10-01

      Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best-estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containments and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior (1) in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and (2) during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included

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

      SciTech Connect (OSTI)

      Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

      2014-07-28

      The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable of handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.

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

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

      Amundson, James; Macridin, Alexandru; Spentzouris, Panagiotis

      2014-07-28

      The development and optimization of particle accelerators are essential for advancing our understanding of the properties of matter, energy, space, and time. Particle accelerators are complex devices whose behavior involves many physical effects on multiple scales. Therefore, advanced computational tools utilizing high-performance computing are essential for accurately modeling them. In the past decade, the US Department of Energy's SciDAC program has produced accelerator-modeling tools that have been employed to tackle some of the most difficult accelerator science problems. The authors discuss the Synergia framework and its applications to high-intensity particle accelerator physics. Synergia is an accelerator simulation package capable ofmore » handling the entire spectrum of beam dynamics simulations. Our authors present Synergia's design principles and its performance on HPC platforms.« less

    19. Determining Interactions in PSA models: Application to a Space PSA

      SciTech Connect (OSTI)

      C. Smith; E. Borgonovo

      2010-06-01

      This paper addresses use of an importance measure interaction study of a probabilistic risk analysis (PSA) performed for a hypothetical aerospace lunar mission. The PSA methods used in this study follow the general guidance provided in the NASA Probabilistic Risk Assessment Procedures Guide for NASA Managers and Practitioners. For the PSA portion, we used phased-based event tree and fault tree logic structures are used to model a lunar mission, including multiple phases (from launch to return to the Earth surface) and multiple critical systems. Details of the analysis results are not provided in this paper instead specific basic events are denoted by number (e.g., the first event is 1, the second is 2, and so on). However, in the model, we used approximately 150 fault trees and over 800 basic events. Following analysis and truncation of cut sets, we were left with about 400 basic events to evaluate. We used this model to explore interactions between different basic events and systems. These sensitivity studies provide high-level insights into features of the PSA for the hypothetical lunar mission.

    20. NREL Computer Models Integrate Wind Turbines with Floating Platforms (Fact Sheet)

      SciTech Connect (OSTI)

      Not Available

      2011-07-01

      Far off the shores of energy-hungry coastal cities, powerful winds blow over the open ocean, where the water is too deep for today's seabed-mounted offshore wind turbines. For the United States to tap into these vast offshore wind energy resources, wind turbines must be mounted on floating platforms to be cost effective. Researchers at the National Renewable Energy Laboratory (NREL) are supporting that development with computer models that allow detailed analyses of such floating wind turbines.

    1. Review of the synergies between computational modeling and experimental characterization of materials across length scales

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

      Dingreville, Rémi; Karnesky, Richard A.; Puel, Guillaume; Schmitt, Jean -Hubert

      2015-11-16

      With the increasing interplay between experimental and computational approaches at multiple length scales, new research directions are emerging in materials science and computational mechanics. Such cooperative interactions find many applications in the development, characterization and design of complex material systems. This manuscript provides a broad and comprehensive overview of recent trends in which predictive modeling capabilities are developed in conjunction with experiments and advanced characterization to gain a greater insight into structure–property relationships and study various physical phenomena and mechanisms. The focus of this review is on the intersections of multiscale materials experiments and modeling relevant to the materials mechanicsmore » community. After a general discussion on the perspective from various communities, the article focuses on the latest experimental and theoretical opportunities. Emphasis is given to the role of experiments in multiscale models, including insights into how computations can be used as discovery tools for materials engineering, rather than to “simply” support experimental work. This is illustrated by examples from several application areas on structural materials. In conclusion this manuscript ends with a discussion on some problems and open scientific questions that are being explored in order to advance this relatively new field of research.« less

    2. Review of the synergies between computational modeling and experimental characterization of materials across length scales

      SciTech Connect (OSTI)

      Dingreville, Rémi; Karnesky, Richard A.; Puel, Guillaume; Schmitt, Jean -Hubert

      2015-11-16

      With the increasing interplay between experimental and computational approaches at multiple length scales, new research directions are emerging in materials science and computational mechanics. Such cooperative interactions find many applications in the development, characterization and design of complex material systems. This manuscript provides a broad and comprehensive overview of recent trends in which predictive modeling capabilities are developed in conjunction with experiments and advanced characterization to gain a greater insight into structure–property relationships and study various physical phenomena and mechanisms. The focus of this review is on the intersections of multiscale materials experiments and modeling relevant to the materials mechanics community. After a general discussion on the perspective from various communities, the article focuses on the latest experimental and theoretical opportunities. Emphasis is given to the role of experiments in multiscale models, including insights into how computations can be used as discovery tools for materials engineering, rather than to “simply” support experimental work. This is illustrated by examples from several application areas on structural materials. In conclusion this manuscript ends with a discussion on some problems and open scientific questions that are being explored in order to advance this relatively new field of research.

    3. Spectroscopy, modeling and computation of metal chelate solubility in supercritical CO{sub 2}

      SciTech Connect (OSTI)

      J. F. Brennecke; M. A. Stadtherr

      1999-12-10

      The overall objectives of this project were to gain a fundamental understanding of the solubility and phase behavior of metal chelates in supercritical CO{sub 2}. Extraction with CO{sub 2} is an excellent way to remove organic compounds from soils, sludges and aqueous solutions, and recent research has demonstrated that, together with chelating agents, it is a viable way to remove metals, as well. In this project the authors sought to gain fundamental knowledge that is vital to computing phase behavior, and modeling and designing processes using CO{sub 2} to separate organics and metal compounds from DOE mixed wastes. The overall program was a comprehensive one to measure, model and compute the solubility of metal chelate complexes in supercritical CO{sub 2} and CO{sub 2}/cosolvent mixtures. Through a combination of phase behavior measurements, spectroscopy and the development of a new computational technique, the authors have achieved a completely reliable way to model metal chelate solubility in supercritical CO{sub 2} and CO{sub 2}/co-contaminant mixtures. Thus, they can now design and optimize processes to extract metals from solid matrices using supercritical CO{sub 2}, as an alternative to hazardous organic solvents that create their own environmental problems, even while helping in metals decontamination.

    4. Orbital-selective Mott phases of a one-dimensional three-orbital Hubbard model studied using computational techniques

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

      Liu, Guangkun; Kaushal, Nitin; Liu, Shaozhi; Bishop, Christopher B.; Wang, Yan; Johnston, Steve; Alvarez, Gonzalo; Moreo, Adriana; Dagotto, Elbio R.

      2016-06-24

      A recently introduced one-dimensional three-orbital Hubbard model displays orbital-selective Mott phases with exotic spin arrangements such as spin block states [J. Rincón et al., Phys. Rev. Lett. 112, 106405 (2014)]. In this paper we show that the constrained-path quantum Monte Carlo (CPQMC) technique can accurately reproduce the phase diagram of this multiorbital one-dimensional model, paving the way to future CPQMC studies in systems with more challenging geometries, such as ladders and planes. The success of this approach relies on using the Hartree-Fock technique to prepare the trial states needed in CPQMC. In addition, we study a simplified version of themore » model where the pair-hopping term is neglected and the Hund coupling is restricted to its Ising component. The corresponding phase diagrams are shown to be only mildly affected by the absence of these technically difficult-to-implement terms. This is confirmed by additional density matrix renormalization group and determinant quantum Monte Carlo calculations carried out for the same simplified model, with the latter displaying only mild fermion sign problems. Lastly, we conclude that these methods are able to capture quantitatively the rich physics of the several orbital-selective Mott phases (OSMP) displayed by this model, thus enabling computational studies of the OSMP regime in higher dimensions, beyond static or dynamic mean-field approximations.« less

    5. CURRENT - A Computer Code for Modeling Two-Dimensional, Chemically Reaccting, Low Mach Number Flows

      SciTech Connect (OSTI)

      Winters, W.S.; Evans, G.H.; Moen, C.D.

      1996-10-01

      This report documents CURRENT, a computer code for modeling two- dimensional, chemically reacting, low Mach number flows including the effects of surface chemistry. CURRENT is a finite volume code based on the SIMPLER algorithm. Additional convergence acceleration for low Peclet number flows is provided using improved boundary condition coupling and preconditioned gradient methods. Gas-phase and surface chemistry is modeled using the CHEMKIN software libraries. The CURRENT user-interface has been designed to be compatible with the Sandia-developed mesh generator and post processor ANTIPASTO and the post processor TECPLOT. This report describes the theory behind the code and also serves as a user`s manual.

    6. Predicting oropharyngeal tumor volume throughout the course of radiation therapy from pretreatment computed tomography data using general linear models

      SciTech Connect (OSTI)

      Yock, Adam D. Kudchadker, Rajat J.; Rao, Arvind; Dong, Lei; Beadle, Beth M.; Garden, Adam S.; Court, Laurence E.

      2014-05-15

      Purpose: The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Methods: Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. Results: In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: −11.6%–23.8%) and 14.6% (range: −7.3%–27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: −6.8%–40.3%) and 13.1% (range: −1.5%–52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: −11.1%–20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. Conclusions: A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography

    7. Computable General Equilibrium Model Fiscal Year 2013 Capability Development Report - April 2014

      SciTech Connect (OSTI)

      Edwards, Brian Keith; Rivera, Michael K.; Boero, Riccardo

      2014-04-01

      This report documents progress made on continued developments of the National Infrastructure Simulation and Analysis Center (NISAC) Computable General Equilibrium Model (NCGEM), developed in fiscal year 2012. In fiscal year 2013, NISAC the treatment of the labor market and tests performed with the model to examine the properties of the solutions computed by the model. To examine these, developers conducted a series of 20 simulations for 20 U.S. States. Each of these simulations compared an economic baseline simulation with an alternative simulation that assumed a 20-percent reduction in overall factor productivity in the manufacturing industries of each State. Differences in the simulation results between the baseline and alternative simulations capture the economic impact of the reduction in factor productivity. While not every State is affected in precisely the same way, the reduction in manufacturing industry productivity negatively affects the manufacturing industries in each State to an extent proportional to the reduction in overall factor productivity. Moreover, overall economic activity decreases when manufacturing sector productivity is reduced. Developers ran two additional simulations: (1) a version of the model for the State of Michigan, with manufacturing divided into two sub-industries (automobile and other vehicle manufacturing as one sub-industry and the rest of manufacturing as the other subindustry); and (2) a version of the model for the United States, divided into 30 industries. NISAC conducted these simulations to illustrate the flexibility of industry definitions in NCGEM and to examine the simulation properties of in more detail.

    8. Efficient Computation of Info-Gap Robustness for Finite Element Models

      SciTech Connect (OSTI)

      Stull, Christopher J.; Hemez, Francois M.; Williams, Brian J.

      2012-07-05

      A recent research effort at LANL proposed info-gap decision theory as a framework by which to measure the predictive maturity of numerical models. Info-gap theory explores the trade-offs between accuracy, that is, the extent to which predictions reproduce the physical measurements, and robustness, that is, the extent to which predictions are insensitive to modeling assumptions. Both accuracy and robustness are necessary to demonstrate predictive maturity. However, conducting an info-gap analysis can present a formidable challenge, from the standpoint of the required computational resources. This is because a robustness function requires the resolution of multiple optimization problems. This report offers an alternative, adjoint methodology to assess the info-gap robustness of Ax = b-like numerical models solved for a solution x. Two situations that can arise in structural analysis and design are briefly described and contextualized within the info-gap decision theory framework. The treatments of the info-gap problems, using the adjoint methodology are outlined in detail, and the latter problem is solved for four separate finite element models. As compared to statistical sampling, the proposed methodology offers highly accurate approximations of info-gap robustness functions for the finite element models considered in the report, at a small fraction of the computational cost. It is noted that this report considers only linear systems; a natural follow-on study would extend the methodologies described herein to include nonlinear systems.

    9. An integrated computer modeling environment for regional land use, air quality, and transportation planning

      SciTech Connect (OSTI)

      Hanley, C.J.; Marshall, N.L.

      1997-04-01

      The Land Use, Air Quality, and Transportation Integrated Modeling Environment (LATIME) represents an integrated approach to computer modeling and simulation of land use allocation, travel demand, and mobile source emissions for the Albuquerque, New Mexico, area. This environment provides predictive capability combined with a graphical and geographical interface. The graphical interface shows the causal relationships between data and policy scenarios and supports alternative model formulations. Scenarios are launched from within a Geographic Information System (GIS), and data produced by each model component at each time step within a simulation is stored in the GIS. A menu-driven query system is utilized to review link-based results and regional and area-wide results. These results can also be compared across time or between alternative land use scenarios. Using this environment, policies can be developed and implemented based on comparative analysis, rather than on single-step future projections. 16 refs., 3 figs., 2 tabs.

    10. Computer modeling of electromagnetic fields and fluid flows for edge containment in continuous casting

      SciTech Connect (OSTI)

      Chang, F.C.; Hull, J.R.; Wang, Y.H.; Blazek, K.E.

      1996-02-01

      A computer model was developed to predict eddy currents and fluid flows in molten steel. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in electromagnetic (EM) edge dams (EMDs) designed at Inland Steel for twin-roll casting. The model can optimize the EMD design so it is suitable for application, and minimize expensive, time-consuming full-scale testing. Numerical simulation was performed by coupling a three-dimensional (3-D) finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve heat transfer, fluid flow, and turbulence transport in a casting process that involves EM fields. ELEKTRA is able to predict the eddy- current distribution and the electromagnetic forces in complex geometries. CaPS-EM is capable of modeling fluid flows with free surfaces. Results of the numerical simulation compared well with measurements obtained from a static test.