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Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Assessing the reliability of linear dynamic transformer thermal modelling  

E-Print Network (OSTI)

Assessing the reliability of linear dynamic transformer thermal modelling X. Mao, D.J. Tylavsky and G.A. McCulla Abstract: Improving the utilisation of transformers requires that the hot-spot and top. An alternative method for assessing transformer model reliability is provided. 1 Introduction The maximally

2

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

E-Print Network (OSTI)

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic conditions with turbine models covering the range of scales important for wind plant dynamics to help address the impacts that upwind turbines have on turbines in their wake and give greater insight into overall wind

3

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

E-Print Network (OSTI)

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic of multi-megawatt turbines requires a new generation of modeling capability to assess individual turbine performance as well as detailed turbine- turbine and turbine-atmosphere interactions. Scientists

4

A system dynamics model for the screening-level long-term assessment of human health risks at contaminated sites  

Science Conference Proceedings (OSTI)

For the design of sustainable and cost-effective management strategies for contaminated sites, decision makers need appropriate tools, i.e. environmental decision support systems to assist them in the planning, assessment, selection and optimisation ... Keywords: Contaminated sites, EDSS, Human health risk assessment, Monitored natural attenuation, Risk-based land management, System dynamics, Uncertainty, Vensim

Ursula S. Mcknight; Michael Finkel

2013-02-01T23:59:59.000Z

5

AVESTAR® - Dynamic Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Modeling Dynamic Modeling The AVESTAR team is pursuing research on the dynamic modeling and simulation of advanced energy systems ranging from power plants to power grids. Dynamic models provide a continuous view of energy systems in action by calculating their transient behavior over time. Plant-wide Models For power plants, dynamic models are used to analyze a wide variety of operating scenarios, including normal base load operation, startup, shutdown, feedstock switchovers, cycling, and load-following. Dynamic process and control models are also essential for analyzing plant responses to setpoint changes and disturbances, as well as malfunctions and abnormal situations. Other applications of plant-wide dynamic models include controllability and operational flexibility analyses, environmental studies, safety evaluations, and risk mitigation.

6

Dynamic Operational Risk Assessment with Bayesian Network  

E-Print Network (OSTI)

Oil/gas and petrochemical plants are complicated and dynamic in nature. Dynamic characteristics include ageing of equipment/components, season changes, stochastic processes, operator response times, inspection and testing time intervals, sequential dependencies of equipment/components and timing of safety system operations, all of which are time dependent criteria that can influence dynamic processes. The conventional risk assessment methodologies can quantify dynamic changes in processes with limited capacity. Therefore, it is important to develop method that can address time-dependent effects. The primary objective of this study is to propose a risk assessment methodology for dynamic systems. In this study, a new technique for dynamic operational risk assessment is developed based on the Bayesian networks, a structure optimal suitable to organize cause-effect relations. The Bayesian network graphically describes the dependencies of variables and the dynamic Bayesian network capture change of variables over time. This study proposes to develop dynamic fault tree for a chemical process system/sub-system and then to map it in Bayesian network so that the developed method can capture dynamic operational changes in process due to sequential dependency of one equipment/component on others. The developed Bayesian network is then extended to the dynamic Bayesian network to demonstrate dynamic operational risk assessment. A case study on a holdup tank problem is provided to illustrate the application of the method. A dryout scenario in the tank is quantified. It has been observed that the developed method is able to provide updated probability different equipment/component failure with time incorporating the sequential dependencies of event occurrence. Another objective of this study is to show parallelism of Bayesian network with other available risk assessment methods such as event tree, HAZOP, FMEA. In this research, an event tree mapping procedure in Bayesian network is described. A case study on a chemical reactor system is provided to illustrate the mapping procedure and to identify factors that have significant influence on an event occurrence. Therefore, this study provides a method for dynamic operational risk assessment capable of providing updated probability of event occurrences considering sequential dependencies with time and a model for mapping event tree in Bayesian network.

Barua, Shubharthi

2012-08-01T23:59:59.000Z

7

Common Information Model (CIM) for Dynamics: Standard Models  

Science Conference Proceedings (OSTI)

This report describes the work accomplished in 2011 and 2012 to develop a standard approach for the exchange of dynamic models and their association to a static power flow model based on the International Electrotechnical Commission (IEC) 61970 Common Information Model (CIM) standards. These exchange models represent the dynamic behavior of the majority of power system components in common use today by electric utilities to perform system simulation studies for system dynamic assessment and for ...

2013-02-05T23:59:59.000Z

8

Regional Dynamics Model (REDYN) | Open Energy Information  

Open Energy Info (EERE)

Regional Dynamics Model (REDYN) Regional Dynamics Model (REDYN) Jump to: navigation, search Tool Summary Name: REDYN Agency/Company /Organization: Regional Dynamics Inc. Sector: Energy Phase: Determine Baseline, "Evaluate Options and Determine Feasibility" is not in the list of possible values (Bring the Right People Together, Create a Vision, Determine Baseline, Evaluate Options, Develop Goals, Prepare a Plan, Get Feedback, Develop Finance and Implement Projects, Create Early Successes, Evaluate Effectiveness and Revise as Needed) for this property., Develop Goals Topics: Market analysis, Policies/deployment programs, Co-benefits assessment, - Macroeconomic Resource Type: Software/modeling tools User Interface: Desktop Application Website: www.regionaldynamics.com/

9

Assessment of Dynamical Downscaling in Near-Surface Fields with Different Spectral Nudging Approaches Using the Nested Regional Climate Model (NRCM)  

Science Conference Proceedings (OSTI)

Dynamic downscaling with regional-scale climate models is used widely for increasing the spatial resolution of global-scale climate model projections. One uncertainty in generating these projections is the choice of boundary forcing applied. In ...

Jiali Wang; Veerabhadra R. Kotamarthi

2013-07-01T23:59:59.000Z

10

Dynamic Mercury Cycling Model Upgrade  

Science Conference Proceedings (OSTI)

This technical update describes the status of activities to upgrade the Dynamic Mercury Cycling Model (D-MCM), an EPRI simulation model that predicts mercury cycling and bioaccumulation in lakes.

2008-12-17T23:59:59.000Z

11

Dynamic model for hydraulic dissipators  

Science Conference Proceedings (OSTI)

The authors propose a mathematical model of a hydraulic link with energy dissipation, the device working reversibly to the alternative traction and compression movement. The dynamic behavior of the energy hydraulic dissipater depends on the instantaneous ... Keywords: dissipater's control, dynamic behavior, hydraulic dissipater, mathematical model

Adrian S. Axinti; Gavril Axinti

2009-03-01T23:59:59.000Z

12

Integrated Assessment Modeling  

Science Conference Proceedings (OSTI)

This paper discusses the role of Integrated Assessment models (IAMs) in climate change research. IAMs are an interdisciplinary research platform, which constitutes a consistent scientific framework in which the large-scale interactions between human and natural Earth systems can be examined. In so doing, IAMs provide insights that would otherwise be unavailable from traditional single-discipline research. By providing a broader view of the issue, IAMs constitute an important tool for decision support. IAMs are also a home of human Earth system research and provide natural Earth system scientists information about the nature of human intervention in global biogeophysical and geochemical processes.

Edmonds, James A.; Calvin, Katherine V.; Clarke, Leon E.; Janetos, Anthony C.; Kim, Son H.; Wise, Marshall A.; McJeon, Haewon C.

2012-10-31T23:59:59.000Z

13

Dynamic modeling of power systems  

Science Conference Proceedings (OSTI)

Morgantown Energy Technology Center`s (METC) Process and Project Engineering (P&PE) personnel continue to refine and modify dynamic modeling or simulations for advanced power systems. P&PE, supported by Gilbert/Commonwealth, Inc. (G/C), has adapted PC/TRAX commercial dynamic software to include equipment found in advanced power systems. PC/TRAX`s software contains the equations that describe the operation of standard power plant equipment such as gas turbines, feedwater pumps, and steam turbines. The METC team has incorporated customized dynamic models using Advanced Continuous Simulation Language (ACSL) code for pressurized circulating fluidized-bed combustors, carbonizers, and other components that are found in Advanced Pressurized Fluidized-Bed Combustion (APFBC) systems. A dynamic model of a commercial-size APFBC power plant was constructed in order to determine representative operating characteristics of the plant and to gain some insight into the best type of control system design. The dynamic model contains both process and control model components. This presentation covers development of a model used to describe the commercial APFBC power plant. Results of exercising the model to simulate plant performance are described and illustrated. Information gained during the APFBC study was applied to a dynamic model of a 1-1/2 generation PFBC system. Some initial results from this study are also presented.

Reed, M.; White, J.

1995-12-01T23:59:59.000Z

14

A unified point process probabilistic framework to assess heartbeat dynamics and autonomic cardiovascular control  

E-Print Network (OSTI)

In recent years, time-varying inhomogeneous point process models have been introduced for assessment of instantaneous heartbeat dynamics as well as specific cardiovascular control mechanisms and hemodynamics. Assessment ...

Chen, Zhe

15

Dynamic modelling of metals - Time scales and target loads  

Science Conference Proceedings (OSTI)

Over the past decade steady-state methods have been developed to assess critical loads of metals avoiding long-term risks in view of food quality and eco-toxicological effects on organisms in soils and surface waters. However, dynamic models are needed ... Keywords: Critical loads, Delay times, Dynamic modelling, Metals, Scenario analysis, Target loads

Maximilian Posch; Wim de Vries

2009-01-01T23:59:59.000Z

16

Assessment of Molecular Modeling & Simulation  

Science Conference Proceedings (OSTI)

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

None

2002-01-03T23:59:59.000Z

17

Environmental Design Space model assessment  

E-Print Network (OSTI)

The Environmental Design Space (EDS) is a multi-disciplinary design tool used to explore trade-offs among aircraft fuel burn, emissions, and noise. This thesis uses multiple metrics to assess an EDS model of a Boeing 777 ...

Spindler, Phillip Michael

2007-01-01T23:59:59.000Z

18

Development and application of a system for dynamic wildfire risk assessment in Italy  

Science Conference Proceedings (OSTI)

In this paper, the architecture and the application of a system designed for the assessment of the distribution of dynamic wildland fire risk over the whole Italian territory are presented. Such an assessment takes place on the basis of static information ... Keywords: Civil protection, Decision support, Forecasting, Fuel moisture model, Risk assessment, Wildfires

Paolo Fiorucci; Francesco Gaetani; Riccardo Minciardi

2008-06-01T23:59:59.000Z

19

A generative model for dynamic canvas motion  

Science Conference Proceedings (OSTI)

We present techniques for constructing realistic canvas and paper models and for enabling interactive dynamic canvas motion. Dynamic canvas motion means that there is a correspondence between the motion of canvas features and the motion of the models ...

Matthew Kaplan; Elaine Cohen

2005-05-01T23:59:59.000Z

20

Assessment of Water Balance Models  

Science Conference Proceedings (OSTI)

Power generating plants perform water balance studies for a variety of reasons, and they use a range of different modeling approaches and tools to accomplish their specific objectives. This EPRI report presents the results of a project conducted with the objective of providing the industry and the interested public with an assessment of the value of water balance models to conserve and manage water. The report provides an overview of the state-of-the-art water balance models and identifies ...

2013-10-29T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Bayesian inference of stochastic dynamical models  

E-Print Network (OSTI)

A new methodology for Bayesian inference of stochastic dynamical models is developed. The methodology leverages the dynamically orthogonal (DO) evolution equations for reduced-dimension uncertainty evolution and the Gaussian ...

Lu, Peter Guang Yi

2013-01-01T23:59:59.000Z

22

Data Assimilation with Gaussian Mixture Models Using the Dynamically Orthogonal Field Equations. Part II: Applications  

Science Conference Proceedings (OSTI)

The properties and capabilities of the Gaussian Mixture Model–Dynamically Orthogonal filter (GMM-DO) are assessed and exemplified by applications to two dynamical systems: 1) the double well diffusion and 2) sudden expansion flows; both of which ...

Thomas Sondergaard; Pierre F. J. Lermusiaux

2013-06-01T23:59:59.000Z

23

Dynamic LES Modeling of a Diurnal Cycle  

Science Conference Proceedings (OSTI)

The diurnally varying atmospheric boundary layer observed during the Wangara (Australia) case study is simulated using the recently proposed locally averaged scale-dependent dynamic subgrid-scale (SGS) model. This tuning-free SGS model enables ...

Sukanta Basu; Jean-François Vinuesa; Andrew Swift

2008-04-01T23:59:59.000Z

24

A Dynamic Model of Thundercloud Electric Fields  

Science Conference Proceedings (OSTI)

A dynamic interactive computer model of the electrical behavior of a thundercloud surrounded by the distributed atmosphere, earth, ionosphere circuit is described. The electrification mechanisms in the model are represented by current or voltage ...

John S. Nisbet

1983-12-01T23:59:59.000Z

25

Dynamical Properties of Model Output Statistics Forecasts  

Science Conference Proceedings (OSTI)

The dynamical properties of forecasts corrected using model output statistics (MOS) schemes are explored, with emphasis on the respective role of model and initial condition uncertainties. Analytical and numerical investigations of low-order ...

S. Vannitsem; C. Nicolis

2008-02-01T23:59:59.000Z

26

The Challenges to Coupling Dynamic Geospatial Models  

SciTech Connect

Many applications of modeling spatial dynamic systems focus on a single system and a single process, ignoring the geographic and systemic context of the processes being modeled. A solution to this problem is the coupled modeling of spatial dynamic systems. Coupled modeling is challenging for both technical reasons, as well as conceptual reasons. This paper explores the benefits and challenges to coupling or linking spatial dynamic models, from loose coupling, where information transfer between models is done by hand, to tight coupling, where two (or more) models are merged as one. To illustrate the challenges, a coupled model of Urbanization and Wildfire Risk is presented. This model, called Vesta, was applied to the Santa Barbara, California region (using real geospatial data), where Urbanization and Wildfires occur and recur, respectively. The preliminary results of the model coupling illustrate that coupled modeling can lead to insight into the consequences of processes acting on their own.

Goldstein, N

2006-06-23T23:59:59.000Z

27

Computational Fluid Dynamics Framework for Turbine Biological Performance Assessment  

SciTech Connect

In this paper, a method for turbine biological performance assessment is introduced to bridge the gap between field and laboratory studies on fish injury and turbine design. Using this method, a suite of biological performance indicators is computed based on simulated data from a computational fluid dynamics (CFD) model of a proposed turbine design. Each performance indicator is a measure of the probability of exposure to a certain dose of an injury mechanism. If the relationship between the dose of an injury mechanism and frequency of injury (dose-response) is known from laboratory or field studies, the likelihood of fish injury for a turbine design can be computed from the performance indicator. By comparing the values of the indicators from various turbine designs, the engineer can identify the more-promising designs. Discussion here is focused on Kaplan-type turbines, although the method could be extended to other designs. Following the description of the general methodology, we will present sample risk assessment calculations based on CFD data from a model of the John Day Dam on the Columbia River in the USA.

Richmond, Marshall C.; Serkowski, John A.; Carlson, Thomas J.; Ebner, Laurie L.; Sick, Mirjam; Cada, G. F.

2011-05-04T23:59:59.000Z

28

TEPP Planning Products Model Needs Assessment Self Assessment Document  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Planning Products Planning Products Model Needs Assessment Self Assessment Document Prepared for the Department of Energy Office of Transportation and Emergency Management 02B00215-13.p65 1 Model Needs Assessment R E V 8 - 0 7 / 2 0 1 2 T r a n s p o r t a t i o n E m e r g e n c y P r e p a r e d n e s s P r o g r a m PURPOSE The purpose of this Model Needs Assessment is to assist state, tribal, or local officials in determining emergency responder readiness for response to a transportation accident involving radioactive material. 1.0 INTRODUCTION This Model Needs Assessment was developed by the Department of Energy's Transportation Emergency Preparedness Program (TEPP) as a planning and assessment tool for state, tribal, or local government officials. To implement this Model Needs Assessment, a designated official

29

Utility of Social Modeling for Proliferation Assessment - Preliminary Assessment  

Science Conference Proceedings (OSTI)

This Preliminary Assessment draft report will present the results of a literature search and preliminary assessment of the body of research, analysis methods, models and data deemed to be relevant to the Utility of Social Modeling for Proliferation Assessment research. This report will provide: 1) a description of the problem space and the kinds of information pertinent to the problem space, 2) a discussion of key relevant or representative literature, 3) a discussion of models and modeling approaches judged to be potentially useful to the research, and 4) the next steps of this research that will be pursued based on this preliminary assessment. This draft report represents a technical deliverable for the NA-22 Simulations, Algorithms, and Modeling (SAM) program. Specifically this draft report is the Task 1 deliverable for project PL09-UtilSocial-PD06, Utility of Social Modeling for Proliferation Assessment. This project investigates non-traditional use of social and cultural information to improve nuclear proliferation assessment, including nonproliferation assessment, proliferation resistance assessments, safeguards assessments and other related studies. These assessments often use and create technical information about the State’s posture towards proliferation, the vulnerability of a nuclear energy system to an undesired event, and the effectiveness of safeguards. This project will find and fuse social and technical information by explicitly considering the role of cultural, social and behavioral factors relevant to proliferation. The aim of this research is to describe and demonstrate if and how social science modeling has utility in proliferation assessment.

Coles, Garill A.; Gastelum, Zoe N.; Brothers, Alan J.; Thompson, Sandra E.

2009-06-01T23:59:59.000Z

30

Hydropower Resource Assessment Modeling Results  

DOE Green Energy (OSTI)

The Hydropower Evaluation Software uses the Federal Energy Regulatory Commission?s Hydroelectric Power Resource Assessment database to identify sites with undeveloped hydropower capacity and the estimated megawatts of undeveloped capacity at each site. The software integrates this information with environmental values from the National Park Service?s National Rivers Inventory database. Other constraints to development that are modeled include Federal and state legislative protection for river segments that have been identified as being wild and scenic river segments. River segments containing threatened and/or endangered wildlife and fish are also modeled for their influence on hydropower development. The amount that each attribute affects the likelihood of development is dependent on the prior development of a site.

A. M. Conner; J. E. Francfort

1999-07-06T23:59:59.000Z

31

Very Large System Dynamics Models - Lessons Learned  

Science Conference Proceedings (OSTI)

This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

Jacob J. Jacobson; Leonard Malczynski

2008-10-01T23:59:59.000Z

32

Modeling and simulation of consumer response to dynamic pricing.  

Science Conference Proceedings (OSTI)

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

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

2012-08-01T23:59:59.000Z

33

Simple Dynamic Gasifier Model That Runs in Aspen Dynamics  

SciTech Connect

Gasification (or partial oxidation) is a vital component of 'clean coal' technology. Sulfur and nitrogen emissions can be reduced, overall energy efficiency is increased, and carbon dioxide recovery and sequestration are facilitated. Gasification units in an electric power generation plant produce a fuel for driving combustion turbines. Gasification units in a chemical plant generate gas, which can be used to produce a wide spectrum of chemical products. Future plants are predicted to be hybrid power/chemical plants with gasification as the key unit operation. The widely used process simulator Aspen Plus provides a library of models that can be used to develop an overall gasifier model that handles solids. So steady-state design and optimization studies of processes with gasifiers can be undertaken. This paper presents a simple approximate method for achieving the objective of having a gasifier model that can be exported into Aspen Dynamics. The basic idea is to use a high molecular weight hydrocarbon that is present in the Aspen library as a pseudofuel. This component should have the same 1:1 hydrogen-to-carbon ratio that is found in coal and biomass. For many plantwide dynamic studies, a rigorous high-fidelity dynamic model of the gasifier is not needed because its dynamics are very fast and the gasifier gas volume is a relatively small fraction of the total volume of the entire plant. The proposed approximate model captures the essential macroscale thermal, flow, composition, and pressure dynamics. This paper does not attempt to optimize the design or control of gasifiers but merely presents an idea of how to dynamically simulate coal gasification in an approximate way.

Robinson, P.J.; Luyben, W.L. [Lehigh University, Bethlehem, PA (United States). Dept. of Chemical Engineering

2008-10-15T23:59:59.000Z

34

On Frontal Dynamics in Two Model Oceans  

Science Conference Proceedings (OSTI)

Vertically homogeneous variable-temperature layer models are often used to describe upper-ocean variability, the dynamics of jets and fronts included. Frontogenesis is known to have a preference for strong cyclonic shears. When a frontal wave ...

Tor Eldevik

2002-10-01T23:59:59.000Z

35

A Dynamical Systems Model for Language Change  

E-Print Network (OSTI)

Formalizing linguists' intuitions of language change as a dynamical system, we quantify the time course of language change including sudden vs. gradual changes in languages. We apply the computer model to the historical ...

Niyogi, Partha

1995-12-01T23:59:59.000Z

36

Short-Term Dynamics of Model Errors  

Science Conference Proceedings (OSTI)

The natural instability of the atmosphere is at the origin of the rapid amplification of errors coming from the uncertainty on the initial conditions and from the imperfect representation (the model) of the atmospheric dynamics. In this paper, ...

S. Vannitsem; Z. Toth

2002-09-01T23:59:59.000Z

37

Modelling the dynamical baroreflex-feedback control  

Science Conference Proceedings (OSTI)

A comprehensive model of the baroreflex-feedback mechanism regulating the heart rate, the contractility of the ventricle and the peripheral vascular resistance is presented. The dynamics of the affector and the effector parts are modelled. For each of ... Keywords: Baroreceptor, Cardiovascular system, Mathematical modelling, Medical applications, Neural biology, Nonlinear feedback mechanism, Nonlinear oscillations

J. T. Ottesen

2000-02-01T23:59:59.000Z

38

Social impact models of opinion dynamics  

E-Print Network (OSTI)

We investigate models of opinion formation which are based on the social impact theory. The following approaches are discussed: (i) general mean field theory of social impact, (ii) a social impact model with learning, (iii) a model of a finite group with a strong leader, (iv) a social impact model with dynamically changing social temperature, (v) a model with individuals treated as active Brownian particles interacting via a communication field. 1

Janusz A. Ho?lyst; Krzysztof Kacperski; Frank Schweitzer; Janusz A. Ho?lyst; Krzysztof Kacperski; Frank Schweitzer

2001-01-01T23:59:59.000Z

39

A Joint Statistical and Dynamical Assessment of Atmospheric Response to North Pacific Oceanic Variability in CCSM3  

Science Conference Proceedings (OSTI)

Atmospheric response to North Pacific oceanic variability is assessed in Community Climate System Model, version 3 (CCSM3) using two statistical methods and one dynamical method. All methods identify an equivalent barotropic low response to a ...

Yafang Zhong; Zhengyu Liu

2008-11-01T23:59:59.000Z

40

Swarm Intelligence for Urban Dynamics Modelling  

Science Conference Proceedings (OSTI)

In this paper, we propose swarm intelligence algorithms to deal with dynamical and spatial organization emergence. The goal is to model and simulate the developement of spatial centers using multi-criteria. We combine a decentralized approach based on emergent clustering mixed with spatial constraints or attractions. We propose an extension of the ant nest building algorithm with multi-center and adaptive process. Typically, this model is suitable to analyse and simulate urban dynamics like gentrification or the dynamics of the cultural equipment in urban area.

Ghnemat, Rawan; Bertelle, Cyrille [LITIS-University of Le Havre 25 rue Philippe Lebon-BP 540 76058 Le Havre cedex (France); Duchamp, Gerard H. E. [LIPN-University of Paris XIII 99 avenue Jean-Baptiste Clement 93430 Villetaneuse (France)

2009-04-16T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Dynamic Model of Facial Cooling  

Science Conference Proceedings (OSTI)

Recent modifications to windchill forecasting have motivated the development of a rate-of-tissue-cooling model for the purpose of predicting facial cooling times. The model assumes a hollow cylindrical geometry with a fixed internal boundary ...

Peter Tikuisis; Randall J. Osczevski

2002-12-01T23:59:59.000Z

42

Dynamics of a fishing model  

Science Conference Proceedings (OSTI)

In this paper, the authors give sufficient conditions for the existence and global attractivity of a positive periodic solution of the first order nonlinear differential equation N?(t) = -a(t)N(t) +b(t) N(t)/1+(N(t)/p(t))? ... Keywords: attractivity, fishing model, periodic solution, population model

John R. Graef; Seshadev Padhi; Shilpee Srivastava

2010-03-01T23:59:59.000Z

43

Dynamic Equilibrium Economies: A Framework for Comparing Models and Data  

E-Print Network (OSTI)

: We propose a constructive, multivariate framework for assessing agreement between (generally misspecified) dynamic equilibrium models and data, which enables a complete second-order comparison of the dynamic properties of models and data. We use bootstrap algorithms to evaluate the significance of deviations between models and data, and we use goodness-of-fit criteria to produce estimators that optimize economically-relevant loss functions. We provide a detailed illustrative application to modeling the U.S. cattle cycle. Acknowledgments: The Co-Editor and referees provided helpful and constructive input, as did participants at meetings of the Econometric Society, the CEPR, the NBER, and numerous university seminars. We gratefully acknowledge additional help from Bill Brown, Fabio Canova, Tim Cogley, Bob Lucas, Ellen McGrattan, Danny Quah, Lucrezia Reichlin, Sherwin Rosen, Chris Sims, Tony Smith, Jim Stock, Mark Watson, and especially Lars Hansen, Adrian Pagan, and Tom Sargent. All re...

Lee E. Ohanian; Jeremy Berkowitz; Francis X. Diebold; Francis X. Diebold; Tim Cogley; Bob Lucas; Ellen Mcgrattan; Danny Quah; Lucrezia Reichlin

1998-01-01T23:59:59.000Z

44

Dynamic Stabilization of Atmospheric Single Column Models  

Science Conference Proceedings (OSTI)

Single column models (SCMs) provide an economical framework for assessing the sensitivity of atmospheric temperature and humidity to natural and imposed perturbations, and also for developing improved representations of diabatic processes in ...

John W. Bergman; Prashant D. Sardeshmukh

2004-03-01T23:59:59.000Z

45

Space, time and nesting Integrated Assessment Models  

Science Conference Proceedings (OSTI)

Integrated Assessment Modelling in the field of air pollution has advanced greatly since the 1985 Helsinki Protocol on the reduction of Sulphur emissions and their transboundary fluxes. With subsequent protocols and increased understanding of the inter-relationships ... Keywords: CLRTAP, Integrated Assessment Modelling, Scale, Science-policy interaction, Space, Time

T. Oxley; H. M. ApSimon

2007-12-01T23:59:59.000Z

46

Analysis of Permafrost Thermal Dynamics and Response to Climate Change in the CMIP5 Earth System Models  

Science Conference Proceedings (OSTI)

The authors analyze global climate model predictions of soil temperature [from the Coupled Model Intercomparison Project phase 5 (CMIP5) database] to assess the models’ representation of current-climate soil thermal dynamics and their predictions ...

Charles D. Koven; William J. Riley; Alex Stern

2013-03-01T23:59:59.000Z

47

Brief Equivalence of hybrid dynamical models  

Science Conference Proceedings (OSTI)

This paper establishes equivalences among five classes of hybrid systems: mixed logical dynamical (MLD) systems, linear complementarity (LC) systems, extended linear complementarity (ELC) systems, piecewise affine (PWA) systems, and max-min-plus-scaling ... Keywords: Equivalent models, Hybrid systems, Piecewise affine systems

W. P. M. H. Heemels; B. De Schutter; A. Bemporad

2001-07-01T23:59:59.000Z

48

Modeling of Reactor Kinetics and Dynamics  

SciTech Connect

In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

Matthew Johnson; Scott Lucas; Pavel Tsvetkov

2010-09-01T23:59:59.000Z

49

Dynamic competition model for construction contractors  

E-Print Network (OSTI)

Dynamic competition in an industry has been an interest of practitioners and researchers because of the expectation that sound understanding of competition in a dynamic way enables a firm to compete better. This dynamic approach considers a firm as an entity in a dynamic system, in which every entity is a profit optimizer responding to market conditions as well as its competitors' actions. In construction, the issue of competition has been focused on competitive bidding, which is a critical mechanism for a contractor to obtain jobs and to generate profits by performing them. Since Friedman's competitive bidding model (1956), various approaches have been developed to improve earlier models. The objective of most models is to find the optimum markup to maximize the expected profit from a firm's perspective. However, to better understand competition in the market, there is the need to analyze this issue from a market perspective. The market perspective provides the consideration about market equilibrium. From previous models and other competition studies, critical missing concepts were identified. In order to find efficient policies that enable a firm to outperform its competitors and to provide an analytical framework of understanding dynamic competition, a system dynamics model has been developed based on the identified concepts. In this model, there are three managerial areas in which a contractor makes policy: 1) markup; 2) marketing; and 3) capacity. Each firm's backlog level is considered as a basic input to its policy making. N firms are equally exposed to demand uncertainty. As an optimizer, each firm applies its policies responding to changes in the market to keep its operations efficient. Firms' responses to market changes are simulated and analyzed and their dynamic feedback was studied. Test results show how difficult it is for a firm to obtain a competitive advantage competing with its competitors due to their reactions. This is different from the previous models that determine a better policy based on assumed static condition and ignorance of competitors' reactions. The test results also show the possibility that one firm can outperform its competitors by using different policies based on accurate market forecasts.

Kim, Hyung Jin

2004-01-01T23:59:59.000Z

50

Feature extraction for structural dynamics model validation  

SciTech Connect

This study focuses on defining and comparing response features that can be used for structural dynamics model validation studies. Features extracted from dynamic responses obtained analytically or experimentally, such as basic signal statistics, frequency spectra, and estimated time-series models, can be used to compare characteristics of structural system dynamics. By comparing those response features extracted from experimental data and numerical outputs, validation and uncertainty quantification of numerical model containing uncertain parameters can be realized. In this study, the applicability of some response features to model validation is first discussed using measured data from a simple test-bed structure and the associated numerical simulations of these experiments. issues that must be considered were sensitivity, dimensionality, type of response, and presence or absence of measurement noise in the response. Furthermore, we illustrate a comparison method of multivariate feature vectors for statistical model validation. Results show that the outlier detection technique using the Mahalanobis distance metric can be used as an effective and quantifiable technique for selecting appropriate model parameters. However, in this process, one must not only consider the sensitivity of the features being used, but also correlation of the parameters being compared.

Hemez, Francois [Los Alamos National Laboratory; Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Nishio, Mayuko [UNIV OF TOKYO; Worden, Keith [UNIV OF SHEFFIELD; Takeda, Nobuo [UNIV OF TOKYO

2010-11-08T23:59:59.000Z

51

ORISE: Dose modeling and assessments  

NLE Websites -- All DOE Office Websites (Extended Search)

or state regulatory compliance requirements are being met during the decontamination and decommissioning of nuclear facilities. Dose modeling is an important step in the...

52

INVENTORY DYNAMICS IMPLEMENTATION TO A NETWORK DESIGN MODEL Format Review.  

E-Print Network (OSTI)

??This research presents an inventory dynamics model that is implemented into an already existing supply chain footprint model for a multinational manufacturing company. The model… (more)

Better Romero, Miguel

2009-01-01T23:59:59.000Z

53

Testing of Hydro-Quebec Cases with Dynamic Security Assessment Package  

Science Conference Proceedings (OSTI)

Transient stability contingencies provided by Hydro-Quebec (HQ) were evaluated by Siemens using two EPRI Dynamic Security Assessment (DSA) software components: Contingency Screening and Ranking and Time Domain Simulation. The main purpose of the HQ collaboration was to ascertain the performance of the EPRI on-line DSA system for the Hydro-Quebec network and test the contingency ranking methodology. During 1995 and 1996, comparing and matching transient stability modeling and ranking a list of HQ continge...

2000-12-11T23:59:59.000Z

54

Applied Dynamic Analysis of the Global Economy (ADAGE) Model | Open Energy  

Open Energy Info (EERE)

Applied Dynamic Analysis of the Global Economy (ADAGE) Model Applied Dynamic Analysis of the Global Economy (ADAGE) Model Jump to: navigation, search LEDSGP green logo.png FIND MORE DIA TOOLS This tool is part of the Development Impacts Assessment (DIA) Toolkit from the LEDS Global Partnership. Tool Summary LAUNCH TOOL Name: Applied Dynamic Analysis of the Global Economy (ADAGE) Model Agency/Company /Organization: Research Triangle Institute Sector: Climate, Energy Topics: Co-benefits assessment, - Macroeconomic, Pathways analysis Resource Type: Software/modeling tools User Interface: Desktop Application Complexity/Ease of Use: Advanced Website: www.rti.org/page.cfm?objectid=DDC06637-7973-4B0F-AC46B3C69E09ADA9 RelatedTo: Electricity Markets Analysis (EMA) Model Cost: Paid Applied Dynamic Analysis of the Global Economy (ADAGE) Model Screenshot

55

Position paper: Selecting among five common modelling approaches for integrated environmental assessment and management  

Science Conference Proceedings (OSTI)

The design and implementation of effective environmental policies need to be informed by a holistic understanding of the system processes (biophysical, social and economic), their complex interactions, and how they respond to various changes. Models, ... Keywords: Agent-based model, Bayesian network, Coupled component model, Integrated assessment, Knowledge-based model, System dynamics

Rebecca A. Kelly (Letcher), Anthony J. Jakeman, Olivier Barreteau, Mark E. Borsuk, Sondoss Elsawah, Serena H. Hamilton, Hans JøRgen Henriksen, Sakari Kuikka, Holger R. Maier, Andrea Emilio Rizzoli, Hedwig Van Delden, Alexey A. Voinov

2013-09-01T23:59:59.000Z

56

Empirical Correction of a Dynamical Model. Part I: Fundamental Issues  

Science Conference Proceedings (OSTI)

The possibility of empirically correcting a nonlinear dynamical model is examined. The empirical correction is constructed by fitting a first-order Markov model to the forecast errors using initial conditions as predictors. The dynamical operator ...

Timothy DelSole; Arthur Y. Hou

1999-11-01T23:59:59.000Z

57

A grid computing based approach for the power system dynamic security assessment  

Science Conference Proceedings (OSTI)

This paper addresses the problem of parallel dynamic security assessment applications from static homogeneous cluster environment to dynamic heterogeneous grid environment. Functional parallelism and data parallelism are supported by each of the message ... Keywords: Adaptive load balancing, Dynamic security assessment, Grid computing, Latency exploitation technique, Modularity

Xingzhi Wang; Zheng Yan; Li Li

2010-05-01T23:59:59.000Z

58

Dynamical model for Pion - Nucleon Bremsstrahlung  

E-Print Network (OSTI)

A dynamical model based on effective Lagrangians is proposed to describe the bremsstrahlung reaction $ \\pi N \\to \\pi N \\gamma$ at low energies. The $\\Delta(1232)$ degrees of freedom are incorporated in a way consistent with both, electromagnetic gauge invariance and invariance under contact transformations. The model also includes the initial and final state rescattering of hadrons via a T-matrix with off-shell effects. The $\\pi N \\gamma$ differential cross sections are calculated using three different T-matrix models and the results are compared with the soft photon approximation, and with experimental data. The aim of this analysis is to test the off-shell behavior of the different T-matrices under consideration.

A. Mariano; G. López Castro

2000-03-31T23:59:59.000Z

59

Dynamic Process of Money Transfer Models  

E-Print Network (OSTI)

We have studied numerically the statistical mechanics of the dynamic phenomena, including money circulation and economic mobility, in some transfer models. The models on which our investigations were performed are the basic model proposed by A. Dragulescu and V. Yakovenko [1], the model with uniform saving rate developed by A. Chakraborti and B.K. Chakrabarti [2], and its extended model with diverse saving rate [3]. The velocity of circulation is found to be inversely related with the average holding time of money. In order to check the nature of money transferring process in these models, we demonstrated the probability distributions of holding time. In the model with uniform saving rate, the distribution obeys exponential law, which indicates money transfer here is a kind of Poisson process. But when the saving rate is set diversely, the holding time distribution follows a power law. The velocity can also be deduced from a typical individual's optimal choice. In this way, an approach for building the micro-...

Wang, Y; Wang, Yougui; Ding, Ning

2005-01-01T23:59:59.000Z

60

Model and Analytic Processes for Export License Assessments  

SciTech Connect

This paper represents the Department of Energy Office of Nonproliferation Research and Development (NA-22) Simulations, Algorithms and Modeling (SAM) Program's first effort to identify and frame analytical methods and tools to aid export control professionals in effectively predicting proliferation intent; a complex, multi-step and multi-agency process. The report focuses on analytical modeling methodologies that alone, or combined, may improve the proliferation export control license approval process. It is a follow-up to an earlier paper describing information sources and environments related to international nuclear technology transfer. This report describes the decision criteria used to evaluate modeling techniques and tools to determine which approaches will be investigated during the final 2 years of the project. The report also details the motivation for why new modeling techniques and tools are needed. The analytical modeling methodologies will enable analysts to evaluate the information environment for relevance to detecting proliferation intent, with specific focus on assessing risks associated with transferring dual-use technologies. Dual-use technologies can be used in both weapons and commercial enterprises. A decision-framework was developed to evaluate which of the different analytical modeling methodologies would be most appropriate conditional on the uniqueness of the approach, data availability, laboratory capabilities, relevance to NA-22 and Office of Arms Control and Nonproliferation (NA-24) research needs and the impact if successful. Modeling methodologies were divided into whether they could help micro-level assessments (e.g., help improve individual license assessments) or macro-level assessment. Macro-level assessment focuses on suppliers, technology, consumers, economies, and proliferation context. Macro-level assessment technologies scored higher in the area of uniqueness because less work has been done at the macro level. An approach to developing testable hypotheses for the macro-level assessment methodologies is provided. The outcome of this works suggests that we should develop a Bayes Net for micro-level analysis and continue to focus on Bayes Net, System Dynamics and Economic Input/Output models for assessing macro-level problems. Simultaneously, we need to develop metrics for assessing intent in export control, including the risks and consequences associated with all aspects of export control.

Thompson, Sandra E.; Whitney, Paul D.; Weimar, Mark R.; Wood, Thomas W.; Daly, Don S.; Brothers, Alan J.; Sanfilippo, Antonio P.; Cook, Diane; Holder, Larry

2011-09-29T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A collaborative framework for multi-area dynamic security assessment of large scale systems  

E-Print Network (OSTI)

that our knowledge of power system dynamics and the quality of available dynamic security analysis software- security assessment (load-flow computations) [4]­[10]. But there remain several open questions which have

Wehenkel, Louis

62

Computational social dynamic modeling of group recruitment.  

SciTech Connect

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.

Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.

2004-01-01T23:59:59.000Z

63

A dynamic system model of biogeography-based optimization  

Science Conference Proceedings (OSTI)

Abstract: We derive a dynamic system model for biogeography-based optimization (BBO) that is asymptotically exact as the population size approaches infinity. The states of the dynamic system are equal to the proportion of each individual in the population; ... Keywords: Biogeography-based optimization, Dynamic system, Evolutionary algorithm, Genetic algorithm, Global uniform recombination, Markov model

Dan Simon

2011-12-01T23:59:59.000Z

64

Dynamic social network analysis using latent space models  

Science Conference Proceedings (OSTI)

This paper explores two aspects of social network modeling. First, we generalize a successful static model of relationships into a dynamic model that accounts for friendships drifting over time. Second, we show how to make it tractable to learn such ...

Purnamrita Sarkar; Andrew W. Moore

2005-12-01T23:59:59.000Z

65

A Simple Model of Stratospheric Dynamics Including Solar Variability  

Science Conference Proceedings (OSTI)

A simple dynamic model, truncated from the stratospheric wave–zonal flow interaction Holton and Mass model, is introduced and studied. This model consists of three ordinary differential equations controlled by two parameters: the initial ...

Alexander Ruzmaikin; John Lawrence; Cristina Cadavid

2003-05-01T23:59:59.000Z

66

Modeling Dynamics of Post Disaster Recovery  

E-Print Network (OSTI)

Natural disasters result in loss of lives, damage to built facilities, and interruption of businesses. The losses are not instantaneous rather they continue to occur until the community is restored to a functional socio-economic entity. Hence, it is essential that policy makers recognize this dynamic aspect of the incurring losses and make realistic plans to enhance the recovery. However, this cannot take place without understanding how homeowners react to recovery signals. These signals can come in different ways: from policy makers showing their strong commitment to restore the community by providing financial support and/or restoration of lifeline infrastructure; or from the neighbors showing their willingness to reconstruct. The goal of this research is to develop a model that can account for homeowners’ dynamic interactions in both organizational and spatial domains. Spatial domain of interactions focuses on how homeowners process signals from the environment such as neighbors reconstructing and local agencies restoring infrastructure, while organizational domain of interactions focuses on how agents process signals from other stakeholders that do not directly affect the environment like insurers. The hypothesis of this study is that these interactions significantly influence decisions to reconstruct and stay, or sell and leave. A multi-agent framework is used to capture emergent behavior such as spatial patterns and formation of clusters. The developed framework is illustrated and validated using experimental data sets.

Nejat, Ali

2011-08-01T23:59:59.000Z

67

Bayesian dynamic models for space-time point processes  

Science Conference Proceedings (OSTI)

In this work we propose a model for the intensity of a space-time point process, specified by a sequence of spatial surfaces that evolve dynamically in time. This specification allows flexible structures for the components of the model, in order to handle ... Keywords: Bayesian inference, Disease mapping, Dynamic models, Integrated Laplace, Monte Carlo Markov chain, Space-time point processes

Edna A. Reis; Dani Gamerman; Marina S. Paez; Thiago G. Martins

2013-04-01T23:59:59.000Z

68

System Dynamics: HyDIVE(TM) (Hydrogen Dynamic Infrastructure and Vehicle Evolution) Model (Presentation)  

DOE Green Energy (OSTI)

This presentation by Cory Welch at the 2007 DOE Hydrogen Program Annual Merit Review Meeting focuses on Hydrogen Dynamic Infrastructure and Vehicle Evolution Model.

Welch, C.

2007-05-16T23:59:59.000Z

69

Introduction to Simplified Generation Risk Assessment Modeling  

Science Conference Proceedings (OSTI)

Life cycle management (LCM) and risk-informed asset management of nuclear power plants can benefit from improved prediction of the effect of equipment failures or degradation on plant productivity. The Generation Risk Assessment (GRA) model described in this report provides a systematic approach to estimating how equipment reliability relates to the risk of future lost generation from trips and derates and to prioritizing components and systems based on their importance to productivity.

2004-01-26T23:59:59.000Z

70

A Game-Theoretical Dynamic Model for Electricity Markets  

E-Print Network (OSTI)

Oct 6, 2010 ... A Game-Theoretical Dynamic Model for Electricity Markets ... forecast horizon, bidding frequency, and some other factors on the price signals.

71

Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics  

DOE Green Energy (OSTI)

Report focuses on understanding how analytical system modeling and data from AFV experiences could improve our understanding of the dynamic forces governing the transition to a hydrogen future.

Welch, C.

2006-02-01T23:59:59.000Z

72

Supercomputer modeling of volcanic eruption dynamics  

DOE Green Energy (OSTI)

Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.

Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

1995-06-01T23:59:59.000Z

73

COMPUTATIONAL FLUID DYNAMICS MODELING ANALYSIS OF COMBUSTORS  

DOE Green Energy (OSTI)

In the current fiscal year FY01, several CFD simulations were conducted to investigate the effects of moisture in biomass/coal, particle injection locations, and flow parameters on carbon burnout and NO{sub x} inside a 150 MW GEEZER industrial boiler. Various simulations were designed to predict the suitability of biomass cofiring in coal combustors, and to explore the possibility of using biomass as a reburning fuel to reduce NO{sub x}. Some additional CFD simulations were also conducted on CERF combustor to examine the combustion characteristics of pulverized coal in enriched O{sub 2}/CO{sub 2} environments. Most of the CFD models available in the literature treat particles to be point masses with uniform temperature inside the particles. This isothermal condition may not be suitable for larger biomass particles. To this end, a stand alone program was developed from the first principles to account for heat conduction from the surface of the particle to its center. It is envisaged that the recently developed non-isothermal stand alone module will be integrated with the Fluent solver during next fiscal year to accurately predict the carbon burnout from larger biomass particles. Anisotropy in heat transfer in radial and axial will be explored using different conductivities in radial and axial directions. The above models will be validated/tested on various fullscale industrial boilers. The current NO{sub x} modules will be modified to account for local CH, CH{sub 2}, and CH{sub 3} radicals chemistry, currently it is based on global chemistry. It may also be worth exploring the effect of enriched O{sub 2}/CO{sub 2} environment on carbon burnout and NO{sub x} concentration. The research objective of this study is to develop a 3-Dimensional Combustor Model for Biomass Co-firing and reburning applications using the Fluent Computational Fluid Dynamics Code.

Mathur, M.P.; Freeman, Mark (U.S. DOE National Energy Technology Laboratory); Gera, Dinesh (Fluent, Inc.)

2001-11-06T23:59:59.000Z

74

Computable General Equilibrium Models for Sustainability Impact Assessment:  

Open Energy Info (EERE)

Computable General Equilibrium Models for Sustainability Impact Assessment: Computable General Equilibrium Models for Sustainability Impact Assessment: Status quo and prospects Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Computable General Equilibrium Models for Sustainability Impact Assessment: Status quo and prospects Agency/Company /Organization: DG Joint Research Centre, European Commission, University of Heidelberg Topics: Co-benefits assessment Resource Type: Guide/manual, Publications, Software/modeling tools User Interface: Other Website: iatools.jrc.ec.europa.eu/docs/ecol_econ_2006.pdf Computable General Equilibrium Models for Sustainability Impact Assessment: Status quo and prospects Screenshot References: Computable general equilibrium models[1] Abstract "Sustainability Impact Assessment (SIA) of economic, environmental, and

75

Ocean Eddy Dynamics in a Coupled Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

The role of mesoscale oceanic eddies is analyzed in a quasigeostrophic coupled ocean–atmosphere model operating at a large Reynolds number. The model dynamics are characterized by decadal variability that involves nonlinear adjustment of the ...

P. Berloff; W. Dewar; S. Kravtsov; J. McWilliams

2007-05-01T23:59:59.000Z

76

Mathematical modeling of irreversible dynamic deformation, micro...  

National Nuclear Security Administration (NNSA)

proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the...

77

A Dynamical Systems Model for Nuclear Power Plant Risk Management  

Science Conference Proceedings (OSTI)

This report provides a mathematical dynamical systems model of the effect of plant processes and programs on nuclear plant safety. That is, it models the safety risk management process. Responses of this model to postulated changes in performance and coupling parameters were verified to be in accordance with experience from years of commercial nuclear power plant operation. A preliminary analysis of the model was performed using the techniques of dynamical systems theory to determine regions of operation...

2003-10-31T23:59:59.000Z

78

TEPP Model Needs Assessment Document | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Model Needs Assessment Document Model Needs Assessment Document TEPP Model Needs Assessment Document The purpose of this Model Needs Assessment is to assist state, tribal, or local officials in determining emergency responder readiness for response to a transportation accident involving radioactive material. This Model Needs Assessment was developed by the Department of Energy's Transportation Emergency Preparedness Program (TEPP) as a planning and assessment tool for state, tribal, or local government officials. To implement this Model Needs Assessment, a designated official from the jurisdiction will conduct a self-assessment by answering various questions. By doing so, the official will determine strengths and identify improvement areas. To support the assessment process, and any proposed recommendations for improvement, this document includes

79

Dynamic Modeling in Solid-Oxide Fuel Cells Controller Design  

SciTech Connect

In this paper, a dynamic model of the solid-oxide fuel cell (SOFC) power unit is developed for the purpose of designing a controller to regulate fuel flow rate, fuel temperature, air flow rate, and air temperature to maintain the SOFC stack temperature, fuel utilization rate, and voltage within operation limits. A lumped model is used to consider the thermal dynamics and the electro-chemial dynamics inside an SOFC power unit. The fluid dynamics at the fuel and air inlets are considered by using the in-flow ramp-rates.

Lu, Ning; Li, Qinghe; Sun, Xin; Khaleel, Mohammad A.

2007-06-28T23:59:59.000Z

80

Wind Energy Assessment using a Wind Turbine with Dynamic Yaw Control.  

E-Print Network (OSTI)

??The goal of this project was to analyze the wind energy potential over Lake Michigan. For this purpose, a dynamic model of a utility-scale wind… (more)

Pervez, Md Nahid

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Dynamics of the Oil Transition: Modeling Capacity, Costs, and Emissions  

E-Print Network (OSTI)

or design of improved production cost models. to assess thelearning which lowers production costs, and resourcewhich increases production costs. Each of these modules are

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

82

Strategies for integrated modeling: The community surface dynamics modeling system example  

Science Conference Proceedings (OSTI)

The Community Surface Dynamics Modeling System (CSDMS) is a community of earth scientists promoting the modeling of earth surface processes by developing and disseminating integrated software modules that predict the movement of fluids, and the flux ... Keywords: Community modeling, Earth surface dynamics, Governance, Model integration

Irina Overeem; Maureen M. Berlin; James P. M. Syvitski

2013-01-01T23:59:59.000Z

83

Assessment of seismic resistance of a basilica-type church under earthquake loading: Modelling and analysis  

Science Conference Proceedings (OSTI)

In this paper a finite element methodology for the static and dynamic non-linear analysis of historical masonry structures is described and applied to a case study. A basilica-type masonry church is analysed in order to assess its structural behaviour ... Keywords: Earthquake loading, FE modeling seismic vulnerability, Historical masonry building, Non-linear analysis, Strengthening techniques

Michele Betti; Andrea Vignoli

2008-04-01T23:59:59.000Z

84

Performance model assessment for multi-junction concentrating photovoltaic systems.  

DOE Green Energy (OSTI)

Four approaches to modeling multi-junction concentrating photovoltaic system performance are assessed by comparing modeled performance to measured performance. Measured weather, irradiance, and system performance data were collected on two systems over a one month period. Residual analysis is used to assess the models and to identify opportunities for model improvement.

Riley, Daniel M.; McConnell, Robert. (Amonix, Inc., Seal Beach, CA); Sahm, Aaron (University of Nevada, Las Vegas, NV); Crawford, Clark (Amonix, Inc., Seal Beach, CA); King, David L.; Cameron, Christopher P.; Foresi, James S. (Emcore, Inc., Albuquerque, NM)

2010-03-01T23:59:59.000Z

85

Dynamic physical and economic modelling of riparian restoration options  

Science Conference Proceedings (OSTI)

A dynamic simulation framework is used to compare benefit-cost ratios of riparian restoration investment strategies to pursue ecosystem service benefits. The model is meant to be adaptable to generic restoration planning applications, with the Middle ... Keywords: Adaptive management, Benefit-cost analysis, Choice experiment, Dynamic simulation, Ecosystem service, Rio Grande, River restoration

Matthew A. Weber; Vincent C. Tidwell; Jennifer A. Thacher

2010-12-01T23:59:59.000Z

86

Recursive modelling in dynamics of delta parallel robot  

Science Conference Proceedings (OSTI)

Recursive matrix relations in kinematics and dynamics of a Delta parallel robot having three revolute actuators are established in this paper. The prototype of the manipulator is a three degrees-of-freedom space mechanism, which consists of a system ... Keywords: Dynamics modelling, Kinematics, Parallel mechanism, Virtual work

Stefan Staicu

2009-03-01T23:59:59.000Z

87

Dynamic heat capacity of the east model and of a bead-spring polymer model.  

SciTech Connect

In this report we have presented a brief review of the glass transition and one means of characterizing glassy materials: linear and nonlinear thermodynamic oscillatory experiments to extract the dynamic heat capacity. We have applied these methods to the east model (a variation of the Ising model for glass forming systems) and a simple polymeric system via molecular dynamics simulation, and our results match what is seen in experiment. For the east model, since the dynamics are so simple, a mathematical model is developed that matches the simulated dynamics. For the polymeric system, since the system is a simulation, we can instantaneously 'quench' the system - removing all vibrational energy - to separate the vibrational dynamics from dynamics associated with particle rearrangements. This shows that the long-time glassy dynamics are due entirely to the particle rearrangements, i.e. basin jumping on the potential energy landscape. Finally, we present an extension of linear dynamic heat capacity to the nonlinear regime.

McCoy, John Dwane (New Mexico Institute of Mining and Technology, Socorro, NM); Brown, Jonathan R. (New Mexico Institute of Mining and Technology, Socorro, NM); Adolf, Douglas Brian

2011-10-01T23:59:59.000Z

88

Financial and Cost Assessment Model (FICAM) | Open Energy Information  

Open Energy Info (EERE)

Financial and Cost Assessment Model (FICAM) Financial and Cost Assessment Model (FICAM) Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Financial and Cost Assessment Model (FICAM) Agency/Company /Organization: UNEP-Risoe Centre Sector: Climate Focus Area: Greenhouse Gas Topics: Finance, Baseline projection, GHG inventory Resource Type: Software/modeling tools User Interface: Spreadsheet Website: tech-action.org/models.htm Cost: Free Financial and Cost Assessment Model (FICAM) Screenshot References: FICAM[1] "The Financial and Cost Assessment Model (FICAM) evaluates the contribution of technologies and practices towards mitigation of greenhouse gases, and carries a comprehensive financial analysis." References ↑ "FICAM" Retrieved from "http://en.openei.org/w/index.php?title=Financial_and_Cost_Assessment_Model_(FICAM)&oldid=383091"

89

Assessment of Tools and Data for System-Level Dynamic Analyses  

SciTech Connect

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

Steven J. Piet; Nick R. Soelberg

2011-06-01T23:59:59.000Z

90

An Assessment Model on Green Degree of Biodegradable Packaging Materials  

Science Conference Proceedings (OSTI)

An assessment model of green degree of biodegradable packaging materials is built. The first-order assessment indexes are composed of environmental properties, energy properties, resource properties and economy and the second order assessment index are ... Keywords: packaging materials, analytic hierarchy process, life cycle assessment

Xiaoming Zuo; Zhaomei Xu

2010-03-01T23:59:59.000Z

91

Symbolic Dynamics in a Matching Labour Market Model  

E-Print Network (OSTI)

In this paper we apply the techniques of symbolic dynamics to the analysis of a labor market which shows large volatility in employment flows. In a recent paper, Bhattacharya and Bunzel \\cite{BB} have found that the discrete time version of the Pissarides-Mortensen matching model can easily lead to chaotic dynamics under standard sets of parameter values. To conclude about the existence of chaotic dynamics in the numerical examples presented in the paper, the Li-Yorke theorem or the Mitra sufficient condition were applied which seems questionable because they may lead to misleading conclusions. Moreover, in a more recent version of the paper, Bhattacharya and Bunzel \\cite{BB1} present new results in which chaos is completely removed from the dynamics of the model. Our paper explores the matching model so interestingly developed by the authors with the following objectives in mind: (i) to show that chaotic dynamics may still be present in the model for standard parameter values; (ii) to clarify some open questions raised by the authors in \\cite{BB}, by providing a rigorous proof of the existence of chaotic dynamics in the model through the computation of topological entropy in a symbolic dynamics setting.

Diana A. Mendes; Vivaldo M. Mendes; J. Sousa Ramos

2006-08-01T23:59:59.000Z

92

Secondary Flow and Upstream Dynamics in Double Bifurcation Model  

E-Print Network (OSTI)

Flow behavior in bifurcation models is of great importance to health risk assessments and pulmonary drug delivery. This is particularly true of secondary flow behavior in multi-bifurcation models. Previously, both numerical ...

Leong, Fong Yew

93

Defining assessment projects and scenarios for policy support: Use of ontology in Integrated Assessment and Modelling  

Science Conference Proceedings (OSTI)

Integrated Assessment and Modelling (IAM) provides an interdisciplinary approach to support ex-ante decision-making by combining quantitative models representing different systems and scales into a framework for integrated assessment. Scenarios in IAM ... Keywords: Collaborative approach, Integration, Knowledge management, Multi-disciplinary teams, Policy assessment

S. Janssen; F. Ewert; Hongtao Li; I. N. Athanasiadis; J. J. F. Wien; O. Thérond; M. J. R. Knapen; I. Bezlepkina; J. Alkan-Olsson; A. E. Rizzoli; H. Belhouchette; M. Svensson; M. K. van Ittersum

2009-12-01T23:59:59.000Z

94

Compressible Convection and Subduction: Kinematic and Dynamic Modeling.  

E-Print Network (OSTI)

??Subduction is a dynamic and time-dependent process which requires time-dependent models for its study. In addition, due to the very high pressures within the Earthâs… (more)

Lee, Changyeol

2010-01-01T23:59:59.000Z

95

Parallel processing in discrimination between models of dynamic systems  

Science Conference Proceedings (OSTI)

The paper considers the problem of determining an optimal observation schedule for discrimination between competing models of a dynamic process. To this end, an approach originating in optimum experimental design is applied. Its use necessitates solving ...

Bartosz Kuczewski; Przemys?aw Baranowski; Dariusz Uci?ski

2005-09-01T23:59:59.000Z

96

Dynamical Modeling of Flow in Cumulus-Filled Boundary Layers  

Science Conference Proceedings (OSTI)

A primitive equation planetary boundary layer (PBL) model is constructed and applied to simulate the downwind evolution of coupled dynamic, thermodynamic and cloud properties in the PBL over warmer mean. A multilayered approach is adopted to ...

Chiu-Wai Yuen

1985-01-01T23:59:59.000Z

97

Chaff Seeding Effects in a Dynamical-Electrical Cloud Model  

Science Conference Proceedings (OSTI)

A two-dimensional, slab-symmetric, time-dependent cloud model has been devised to simulate deep convection in the atmosphere. The dynamics and thermodynamics of deep convection are prescribed and the microphysics of the liquid phase is ...

John H. Helsdon Jr.

1980-09-01T23:59:59.000Z

98

A Representation of Variable Root Distribution in Dynamic Vegetation Models  

Science Conference Proceedings (OSTI)

Root distribution is treated as a static component in most current dynamic vegetation models (DVMs). While changes in leaf and stem biomass are reflected in leaf area index (LAI) and vegetation height via specific leaf area (SLA) and allometric ...

Vivek K. Arora; George J. Boer

2003-06-01T23:59:59.000Z

99

Applications of axial and radial compressor dynamic system modeling  

E-Print Network (OSTI)

The presented work is a compilation of four different projects related to axial and centrifugal compression systems. The projects are related by the underlying dynamic system modeling approach that is common in all of them. ...

Spakovszky, Zoltán S. (Zoltán Sándor), 1972-

2001-01-01T23:59:59.000Z

100

Vorticity Dynamics and Zonally Averaged Ocean Circulation Models  

Science Conference Proceedings (OSTI)

Diagnostic equations relating the zonally averaged overturning circulation to north–south density variations are derived and used to determine a new closure scheme for use in zonally averaged ocean models. The presentation clarifies the dynamical ...

Daniel G. Wright; Cornelis B. Vreugdenhil; Tertia M. C. Hughes

1995-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Analytical modeling of SRAM dynamic stability  

Science Conference Proceedings (OSTI)

In this paper, for the first time, a theory for evaluating dynamic noise margins of SRAM cells is developed analytically. The results allow predicting the transient error susceptibility of an SRAM cell using a closed-form expression. The key innovation ...

Bin Zhang; Ari Arapostathis; Sani Nassif; Michael Orshansky

2006-11-01T23:59:59.000Z

102

A Dynamic Model of the Indoor Channel  

Science Conference Proceedings (OSTI)

This paper proposes a new approach to modeling the radio channel experienced by transceivers moving in an indoor environment. For modeling the time-varying impulse response (IR) a randomly time-varying power-delay profile (PDP) is used, which ... Keywords: channel measurements, indoor channel modeling, ray clustering, time-varying PDP, wide band model

Jesper Ødum Nielsen; Valentine Afanassiev; Jørgen Bach Andersen

2001-11-01T23:59:59.000Z

103

Developing Generic Dynamic Models for the 2030 Eastern Interconnection Grid  

SciTech Connect

The Eastern Interconnection Planning Collaborative (EIPC) has built three major power flow cases for the 2030 Eastern Interconnection (EI) based on various levels of energy/environmental policy conditions, technology advances, and load growth. Using the power flow cases, this report documents the process of developing the generic 2030 dynamic models using typical dynamic parameters. The constructed model was validated indirectly using the synchronized phasor measurements by removing the wind generation temporarily.

Kou, Gefei [ORNL] [ORNL; Hadley, Stanton W [ORNL] [ORNL; Markham, Penn N [ORNL] [ORNL; Liu, Yilu [ORNL] [ORNL

2013-12-01T23:59:59.000Z

104

Modeling System Development for the Evaluation of Dynamic Air Quality  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling System Development for the Evaluation of Dynamic Air Quality Modeling System Development for the Evaluation of Dynamic Air Quality Impacts of DER Speaker(s): Robert Van Buskirk Date: January 30, 2003 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Kristina LaCommare A critical challenge for the atmospheric sciences is to understand the anthropogenic impacts on atmospheric chemistry over spatial scales ranging from the urban to the regional, and ultimately to the global, and over corresponding time scales ranging from minutes to weeks and ultimately annual trends. A similar challenge for energy policymakers is to integrate an understanding of impact dynamics into the economic dynamics of energy supply and demand. The challenges of dynamic analysis of emissions impacts from the energy sector have substantially increased with a new

105

Regional assessment of sampling techniques for more efficient dynamical climate downscaling  

Science Conference Proceedings (OSTI)

Dynamical downscaling is a computationally expensive method whereby fine-scale details of the atmosphere may be portrayed by running a limited area numerical weather prediction model (often called a regional climate model) nested within a coarse ...

James O. Pinto; Andrew J. Monaghan; Luca Delle Monache; Emilie Vanvyve; Daran L. Rife

106

A flexible and dynamic algorithm for assessment and optimization of utility sectors  

Science Conference Proceedings (OSTI)

This paper presents a flexible and dynamic algorithm for total assessment, ranking, and optimization of utility sectors. Data envelopment analysis (DEA), corrected ordinary least square (COLS), and stochastic frontier analysis (SFA) are employed for ... Keywords: Assessment, Corrected ordinary least squares, Data envelopment analysis, Optimization, Stochastic frontier analysis, Utility sector

A. Azadeh; H. Eivazy; M. Moghaddam

2010-11-01T23:59:59.000Z

107

ERCOT's Dynamic Model of Wind Turbine Generators: Preprint  

DOE Green Energy (OSTI)

By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.

Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.

2005-08-01T23:59:59.000Z

108

Modeling dynamic diurnal patterns in high frequency financial data  

E-Print Network (OSTI)

-t-EGARCH and can be used to contribute to studies of high-frequency asset returns including the seminal paper by Andersen and Bollerslev (1998). Although we use the DCS model as a vehicle for illustrating the usefulness of the dynamic cubic spline for high... ) independently study decomposition models for estimating the conditional dynamics of p via the logit link. An interesting extension of our model is a hybrid spline-DCS model 7The unconditional nth moment of X is well-defined as long as it is well-defined for F...

Ito, Ryoko

2013-04-19T23:59:59.000Z

109

Assessment of Gas Turbine Combustion Dynamics Monitoring Technologies: Interim Report  

Science Conference Proceedings (OSTI)

This report examines commercially available combustion dynamics monitoring systems (CDMS) and monitoring centers for use on gas turbine engines, specifically 7FA, 501F/5000F/8000H engines. The report provides a current review of combustion monitoring issues and methods, details of operation and available features for various CDMS, including, interviews with equipment suppliers and monitoring center providers, and end-user interviews.BackgroundGas turbines are ...

2013-12-18T23:59:59.000Z

110

Engine spray combustion modeling using unified spray model with dynamic mesh refinement.  

E-Print Network (OSTI)

??The primary objective of this study is to improve the spray and combustion modeling of internal combustion engines using dynamic mesh refinement. The first part… (more)

Kolakaluri, Ravi

2009-01-01T23:59:59.000Z

111

Dynamic (G2) Model Design Document, 24590-WTP-MDD-PR-01-002, Rev. 12  

SciTech Connect

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) Statement of Work (Department of Energy Contract DE-AC27-01RV14136, Section C) requires the contractor to develop and use process models for flowsheet analyses and pre-operational planning assessments. The Dynamic (G2) Flowsheet is a discrete-time process model that enables the project to evaluate impacts to throughput from eventdriven activities such as pumping, sampling, storage, recycle, separation, and chemical reactions. The model is developed by the Process Engineering (PE) department, and is based on the Flowsheet Bases, Assumptions, and Requirements Document (24590-WTP-RPT-PT-02-005), commonly called the BARD. The terminologies of Dynamic (G2) Flowsheet and Dynamic (G2) Model are interchangeable in this document. The foundation of this model is a dynamic material balance governed by prescribed initial conditions, boundary conditions, and operating logic. The dynamic material balance is achieved by tracking the storage and material flows within the plant as time increments. The initial conditions include a feed vector that represents the waste compositions and delivery sequence of the Tank Farm batches, and volumes and concentrations of solutions in process equipment before startup. The boundary conditions are the physical limits of the flowsheet design, such as piping, volumes, flowrates, operation efficiencies, and physical and chemical environments that impact separations, phase equilibriums, and reaction extents. The operating logic represents the rules and strategies of running the plant.

Deng, Yueying; Kruger, Albert A.

2013-12-16T23:59:59.000Z

112

AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS  

Science Conference Proceedings (OSTI)

The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

2011-01-01T23:59:59.000Z

113

Health impact assessment of air pollution using a dynamic exposure profile: Implications for exposure and health impact estimates  

SciTech Connect

In both ambient air pollution epidemiology and health impact assessment an accurate assessment of the population exposure is crucial. Although considerable advances have been made in assessing human exposure outdoors, the assessments often do not consider the impact of individual travel behavior on such exposures. Population-based exposures to NO{sub 2} and O{sub 3} using only home addresses were compared with models that integrate all time-activity patterns-including time in commute-for Flanders and Brussels. The exposure estimates were used to estimate the air pollution impact on years of life lost due to respiratory mortality. Health impact of NO{sub 2} using an exposure that integrates time-activity information was on average 1.2% higher than when assuming that people are always at their home address. For ozone the overall estimated health impact was 0.8% lower. Local differences could be much larger, with estimates that differ up to 12% from the exposure using residential addresses only. Depending on age and gender, deviations from the population average were seen. Our results showed modest differences on a regional level. At the local level, however, time-activity patterns indicated larger differences in exposure and health impact estimates, mainly for people living in more rural areas. These results suggest that for local analyses the dynamic approach can contribute to an improved assessment of the health impact of various types of pollution and to the understanding of exposure differences between population groups. - Highlights: Black-Right-Pointing-Pointer Exposure to ambient air pollution was assessed integrating population mobility. Black-Right-Pointing-Pointer This dynamic exposure was integrated into a health impact assessment. Black-Right-Pointing-Pointer Differences between the dynamic and residential exposure were quantified. Black-Right-Pointing-Pointer Modest differences in health impact were found at a regional level. Black-Right-Pointing-Pointer At municipal level larger differences were found, influenced by gender and age.

Dhondt, Stijn, E-mail: stijn.dhondt@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Beckx, Carolien, E-mail: Carolien.Beckx@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Degraeuwe, Bart, E-mail: Bart.Degraeuwe@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Lefebvre, Wouter, E-mail: Wouter.Lefebvre@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Kochan, Bruno, E-mail: Bruno.Kochan@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Bellemans, Tom, E-mail: Tom.Bellemans@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Int Panis, Luc, E-mail: Luc.intpanis@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Macharis, Cathy, E-mail: cjmachar@vub.ac.be [Department MOSI-Transport and Logistics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels (Belgium); Putman, Koen, E-mail: kputman@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Interuniversity Centre for Health Economics Research (I-CHER), Vrije Universiteit Brussel, Brussels (Belgium)

2012-09-15T23:59:59.000Z

114

Identification and modeling for non-linear dynamic system using neural networks type MLP  

Science Conference Proceedings (OSTI)

In control systems, the model dynamics of linear systems is the principal and most important phase of a project, but when working with dynamic of non-linear systems obtain the model becomes a very complex task can be used techniques of system identification. ... Keywords: LP, algorithms, dynamic backprogation, modeling, multilayer perceptrons, neural networks dynamics, non-linear dynamics, training

Hernán González Acuña; Max Suell Dutra; Omar Lengerke

2009-06-01T23:59:59.000Z

115

Petri net modeling of fault analysis for probabilistic risk assessment.  

E-Print Network (OSTI)

??Fault trees and event trees have been widely accepted as the modeling strategy to perform Probabilistic Risk Assessment (PRA). However, there are several limitations associated… (more)

Lee, Andrew

2013-01-01T23:59:59.000Z

116

DYNAMICAL MODEL OF AN EXPANDING SHELL  

Science Conference Proceedings (OSTI)

Expanding blast waves are ubiquitous in many astronomical sources, such as supernova remnants, X-ray emitting binaries, and gamma-ray bursts. I consider here the dynamics of such an expanding blast wave, both in the adiabatic and the radiative regimes. As the blast wave collects material from its surroundings, it decelerates. A full description of the temporal evolution of the blast wave requires consideration of both the energy density and the pressure of the shocked material. The obtained equation is different from earlier works in which only the energy was considered. The solution converges to the familiar results in both the ultrarelativistic and the sub-relativistic (Newtonian) regimes.

Pe'er, Asaf [Harvard-Smithsonian Center for Astrophysics, MS-51, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-06-10T23:59:59.000Z

117

Dynamic language modeling for European Portuguese  

Science Conference Proceedings (OSTI)

This paper reports on the work done on vocabulary and language model daily adaptation for a European Portuguese broadcast news transcription system. The proposed adaptation framework takes into consideration European Portuguese language characteristics, ... Keywords: Automatic speech recognition (ASR), Broadcast news transcription, Information retrieval techniques, Language modeling, Vocabulary selection

Ciro Martins; António Teixeira; João Neto

2010-10-01T23:59:59.000Z

118

Modeling Shapes and Dynamics of Confined Bubbles  

E-Print Network (OSTI)

section used in microfluidic devices or very complex geometries found in disordered materials. To provide of Mechanical Engineering, University of California, Santa Barbara, California 93106-5070; email: bud@engineering cannot be explained by two-phase flow models in circular capillaries. These models also cannot accurately

Ajaev, Vladimir

119

Modeling dynamic developable meshes by the Hamilton principle  

Science Conference Proceedings (OSTI)

In this paper, a new dynamic developable surface model is proposed. The proposed model represents developable surfaces using triangle meshes. A novel algorithm is proposed to introduce the Hamilton principle into these meshes such that the resulting ... Keywords: Developable surface, Hamilton principle, Physical-based simulation

Yong-Jin Liu; Kai Tang; Ajay Joneja

2007-09-01T23:59:59.000Z

120

DYNASTORE - A Computer Model for Quantifying Dynamic Energy Storage Benefits  

Science Conference Proceedings (OSTI)

Now in development, the DYNASTORE computer model is the first production cost model designed to accurately represent changes in the utility daily load. By quantifying the dynamic benefits of energy storage, it highlights the significant cost savings linked with this technology.

1987-12-16T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Wind turbine control systems: Dynamic model development using system identification and the fast structural dynamics code  

DOE Green Energy (OSTI)

Mitigating the effects of damaging wind turbine loads and responses extends the lifetime of the turbine and, consequently, reduces the associated Cost of Energy (COE). Active control of aerodynamic devices is one option for achieving wind turbine load mitigation. Generally speaking, control system design and analysis requires a reasonable dynamic model of {open_quotes}plant,{close_quotes} (i.e., the system being controlled). This paper extends the wind turbine aileron control research, previously conducted at the National Wind Technology Center (NWTC), by presenting a more detailed development of the wind turbine dynamic model. In prior research, active aileron control designs were implemented in an existing wind turbine structural dynamics code, FAST (Fatigue, Aerodynamics, Structures, and Turbulence). In this paper, the FAST code is used, in conjunction with system identification, to generate a wind turbine dynamic model for use in active aileron control system design. The FAST code is described and an overview of the system identification technique is presented. An aileron control case study is used to demonstrate this modeling technique. The results of the case study are then used to propose ideas for generalizing this technique for creating dynamic models for other wind turbine control applications.

Stuart, J.G.; Wright, A.D.; Butterfield, C.P.

1996-10-01T23:59:59.000Z

122

Highly Efficient Modeling of Dynamic Coronal Loops  

E-Print Network (OSTI)

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated quasi-independently by nanoflares. It is therefore an enormous undertaking to model an entire active region or the global corona. Three-dimensional MHD codes have inadequate spatial resolution, and 1D hydro codes are too slow to simulate the many thousands of elemental strands that must be treated in a reasonable representation. Fortunately, thermal conduction and flows tend to smooth out plasma gradients along the magnetic field, so "0D models" are an acceptable alternative. We have developed a highly efficient model called Enthalpy-Based Thermal Evolution of Loops (EBTEL) that accurately describes the evolution of the average temperature, pressure, and density along a coronal strand. It improves significantly upon earlier models of this type--in accuracy, flexibility, and capability. It ...

Klimchuk, J A; Cargill, P J

2007-01-01T23:59:59.000Z

123

Assessing Carbon Dynamics in Semiarid Ecosystems: Balancing Potential Gains with Potential Large Rapid Losses  

NLE Websites -- All DOE Office Websites (Extended Search)

Assessing Carbon Dynamics in Semiarid Ecosystems: Assessing Carbon Dynamics in Semiarid Ecosystems: Balancing Potential Gains With Potential Large Rapid Losses David D. Breshears (daveb@lanl.gov; 505-665-2803) Environmental Dynamics and Spatial Analysis Group (EES-10), Mail Stop J495 Earth and Environmental Sciences Division Los Alamos National Laboratory Los Alamos, NM 87545 Michael H. Ebinger (mhe@lanl.gov, 505-667-4417) Environmental Dynamics and Spatial Analysis Group (EES-10), Mail Stop J495 Earth and Environmental Sciences Division Los Alamos National Laboratory Los Alamos, NM 87545 Pat J. Unkefer (punkefer@lanl.gov, 505-665-2803) Biosciences Division, BS-1 Los Alamos National Laboratory Los Alamos, NM 87545 Craig D. Allen (craig_allen@usgs.gov, 505-672-3861, Ext. 541) U. S. Geological Survey, Midcontinent Ecological Science Center

124

Sensitivity Properties of a Biosphere Model Based on BATS and a Statistical-Dynamical Climate Model  

Science Conference Proceedings (OSTI)

A biosphere model based on the Biosphere-Atmosphere Transfer Scheme (BATS) and the Saltzman-Vernekar (SV) statistical-dynamical climate model is developed. Some equations of BATS are adopted either intact or with modifications, some are ...

Taiping Zhang

1994-06-01T23:59:59.000Z

125

Clustering Properties of Dynamical Dark Energy Models  

E-Print Network (OSTI)

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is coupled to dark matter.

P. P. Avelino; L. M. G. Beca; C. J. A. P. Martins

2008-02-01T23:59:59.000Z

126

A dynamic model of industrial energy demand in Kenya  

Science Conference Proceedings (OSTI)

This paper analyses the effects of input price movements, technology changes, capacity utilization and dynamic mechanisms on energy demand structures in the Kenyan industry. This is done with the help of a variant of the second generation dynamic factor demand (econometric) model. This interrelated disequilibrium dynamic input demand econometric model is based on a long-term cost function representing production function possibilities and takes into account the asymmetry between variable inputs (electricity, other-fuels and Tabour) and quasi-fixed input (capital) by imposing restrictions on the adjustment process. Variations in capacity utilization and slow substitution process invoked by the relative input price movement justifies the nature of input demand disequilibrium. The model is estimated on two ISIS digit Kenyan industry time series data (1961 - 1988) using the Iterative Zellner generalized least square method. 31 refs., 8 tabs.

Haji, S.H.H. [Gothenburg Univ. (Sweden)

1994-12-31T23:59:59.000Z

127

Highly Efficient Modeling of Dynamic Coronal Loops  

E-Print Network (OSTI)

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated quasi-independently by nanoflares. It is therefore an enormous undertaking to model an entire active region or the global corona. Three-dimensional MHD codes have inadequate spatial resolution, and 1D hydro codes are too slow to simulate the many thousands of elemental strands that must be treated in a reasonable representation. Fortunately, thermal conduction and flows tend to smooth out plasma gradients along the magnetic field, so "0D models" are an acceptable alternative. We have developed a highly efficient model called Enthalpy-Based Thermal Evolution of Loops (EBTEL) that accurately describes the evolution of the average temperature, pressure, and density along a coronal strand. It improves significantly upon earlier models of this type--in accuracy, flexibility, and capability. It treats both slowly varying and highly impulsive coronal heating; it provides the differential emission measure distribution, DEM(T), at the transition region footpoints; and there are options for heat flux saturation and nonthermal electron beam heating. EBTEL gives excellent agreement with far more sophisticated 1D hydro simulations despite using four orders of magnitude less computing time. It promises to be a powerful new tool for solar and stellar studies.

J. A. Klimchuk; S. Patsourakos; P. J. Cargill

2007-10-01T23:59:59.000Z

128

Molecular dynamics study of sodium using a model pseudopotential  

Science Conference Proceedings (OSTI)

The dynamics of sodium is investigated using the coulomb and Born-Mayer interaction augmented by a model pseudopotential to represent the electron interactions including screening, exchange, and correlation. The model parameters were previously determined and have been shown to accurately reproduce experimental equation-of-state, lattice vibration, and crystal phase properties of sodium in the harmonic limit. In this paper the equation-of-state and structural properties are examined in molecular dynamics calculations. The long range effects of the potential are included. Typically, each particle interacts with about 500 neighbors. The calculated equation of state of sodium in the hcp, bcc, and liquid structures is discussed.

Swanson, R.E.; Straub, G.K.; Holian, B.L.

1981-01-01T23:59:59.000Z

129

Dynamic crack initiation toughness : experiments and peridynamic modeling.  

SciTech Connect

This is a dissertation on research conducted studying the dynamic crack initiation toughness of a 4340 steel. Researchers have been conducting experimental testing of dynamic crack initiation toughness, K{sub Ic}, for many years, using many experimental techniques with vastly different trends in the results when reporting K{sub Ic} as a function of loading rate. The dissertation describes a novel experimental technique for measuring K{sub Ic} in metals using the Kolsky bar. The method borrows from improvements made in recent years in traditional Kolsky bar testing by using pulse shaping techniques to ensure a constant loading rate applied to the sample before crack initiation. Dynamic crack initiation measurements were reported on a 4340 steel at two different loading rates. The steel was shown to exhibit a rate dependence, with the recorded values of K{sub Ic} being much higher at the higher loading rate. Using the knowledge of this rate dependence as a motivation in attempting to model the fracture events, a viscoplastic constitutive model was implemented into a peridynamic computational mechanics code. Peridynamics is a newly developed theory in solid mechanics that replaces the classical partial differential equations of motion with integral-differential equations which do not require the existence of spatial derivatives in the displacement field. This allows for the straightforward modeling of unguided crack initiation and growth. To date, peridynamic implementations have used severely restricted constitutive models. This research represents the first implementation of a complex material model and its validation. After showing results comparing deformations to experimental Taylor anvil impact for the viscoplastic material model, a novel failure criterion is introduced to model the dynamic crack initiation toughness experiments. The failure model is based on an energy criterion and uses the K{sub Ic} values recorded experimentally as an input. The failure model is then validated against one class of problems showing good agreement with experimental results.

Foster, John T.

2009-10-01T23:59:59.000Z

130

Vorton dynamics: a case study of developing a fluid dynamics model for a vector processor  

Science Conference Proceedings (OSTI)

The raw performance of vector processors such as the CDC CYBER-205 has been well documented. The ability to apply this raw power to ever more complex algebraic algorithms has been reported in [9]. The final step in making computers of this class truly ... Keywords: CYBER-205, computational fluid dynamics, programming, vorton model

M. J. Kascic, Jr.

1984-08-01T23:59:59.000Z

131

ANL/ALCF/ESP-13/8 Using Multi-scale Dynamic Rupture Models to  

NLE Websites -- All DOE Office Websites (Extended Search)

Using Multi-scale Dynamic Rupture Models to Improve Ground Motion Estimates PI: Thomas Jordan ESP Postdoc: Geoffrey Ely Science Overview This project uses dynamic rupture...

132

Integration of agricultural and energy system models for biofuel assessment  

Science Conference Proceedings (OSTI)

This paper presents a coupled modeling framework to capture the dynamic linkages between agricultural and energy markets that have been enhanced through the expansion of biofuel production, as well as the environmental impacts resulting from this expansion. ... Keywords: Agricultural markets, Biofuels, Energy systems, Environment, Modeling

A. Elobeid, S. Tokgoz, R. Dodder, T. Johnson, O. Kaplan, L. Kurkalova, S. Secchi

2013-10-01T23:59:59.000Z

133

A theoretical approach for dynamic modelling of sustainable development  

Science Conference Proceedings (OSTI)

This article presents a theoretical model for a dynamic system based on sustainable development. Due to the relatively absence of theoretical studies and practical issues in the area of sustainable development, Romania aspires to the principles of sustainable ... Keywords: economic development, economic system, economic welfare, natural environment, resources scarcity, sustainable development

Corina-Maria Ene; Anda Gheorghiu; Anca Gheorghiu

2011-02-01T23:59:59.000Z

134

Dynamic predication model for integrated series and application  

Science Conference Proceedings (OSTI)

In the paper a predication model for integrated series is proposed. Granger causality analysis is deployed first for finding out the cointegrated series for the interested series. Then granger causality information is used for the identification of the ... Keywords: cointegration series, dynamic prediction, electricity demand, granger causality

Yuan Jia-hai; Zhao Zhi; Xiong Min-peng

2006-11-01T23:59:59.000Z

135

Dynamic world model with the lazy potential function  

Science Conference Proceedings (OSTI)

One of the fundamental skills of an autonomous mobile robot is its ability to determine a collision-free path in a dynamically changing environment. To meet this challenge, robots often have their own world model - an internal representation of the environment. ...

Konrad Ku?akowski; Tomasz St?pie?

2011-06-01T23:59:59.000Z

136

Modelling life cycle and population dynamics of Nostocales (cyanobacteria)  

Science Conference Proceedings (OSTI)

Cyanobacteria of the order Nostocales found in lakes in temperate regions are generally assumed to benefit from climate change. To predict their future development under varying environmental conditions, we developed a mathematical model that simulates ... Keywords: Cylindrospermopsis raciborskii, Hasse diagram, Life cycle, Nostocales, Population dynamics, Shallow lake

K. D. Jöhnk; R. Brüggemann; J. Rücker; B. Luther; U. Simon; B. Nixdorf; C. Wiedner

2011-05-01T23:59:59.000Z

137

A pseudo-equilibrium thermodynamic model of information processing in nonlinear brain dynamics  

E-Print Network (OSTI)

Haven CT: Yale U. P. Thermodynamic model of brain dynamicsNeurophysiol. 117(3), Thermodynamic model of brain dynamicsA far-from-equilibrium thermodynamic model of the action-

Freeman, Walter J III

2008-01-01T23:59:59.000Z

138

Gauge turbulence, topological defect dynamics, and condensation in Higgs models  

E-Print Network (OSTI)

The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appear in the gauge field which are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signalled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang-Mills fields and potential mechanisms how confinement and condensation in non-abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.

Thomas Gasenzer; Larry McLerran; Jan M. Pawlowski; Dénes Sexty

2013-07-19T23:59:59.000Z

139

Agent-based modeling and systems dynamics model reproduction.  

Science Conference Proceedings (OSTI)

Reproducibility is a pillar of the scientific endeavour. We view computer simulations as laboratories for electronic experimentation and therefore as tools for science. Recent studies have addressed model reproduction and found it to be surprisingly difficult to replicate published findings. There have been enough failed simulation replications to raise the question, 'can computer models be fully replicated?' This paper answers in the affirmative by reporting on a successful reproduction study using Mathematica, Repast and Swarm for the Beer Game supply chain model. The reproduction process was valuable because it demonstrated the original result's robustness across modelling methodologies and implementation environments.

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

2009-01-01T23:59:59.000Z

140

Microsoft PowerPoint - Real-Time Dynamic Brake Assessment poster.ppt [Compatibility Mode]  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Brake Assessment Dynamic Brake Assessment Purpose Conduct a proof-of-concept test to examine the feasibility of developing an on-board system to assess a vehicle's ability to stop based on typical low-pressure in-service braking events. Partnerships H.T. Hackney Company MGM Brakes Overview Funded through the Federal Motor Carrier Safety Administration's Vehicle and Roadside Operations Division Concept stemming from on the Department of Energy's Medium Truck Duty Cycle research as well as previous research conducted for the National Highway Transportation Safety Administration. Signals to be collected Real-time brake application pressure Vehicle speed and acceleration GPS location and grade information Vehicle weight (current load) Engine parameters such as RPM and torque To be conducted October 2010 -

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141

A framework for modeling payments for ecosystem services with agent-based models, Bayesian belief networks and opinion dynamics models  

Science Conference Proceedings (OSTI)

We present an integrated modeling framework for simulating land-use decision making under the influence of payments for ecosystem services. The model combines agent-based modeling (ABM) with Bayesian belief networks (BBNs) and opinion dynamics models ... Keywords: Agent based modeling, Bayesian network, China, Human-environment interaction, IAMO-LUC, Land use change, Payments for environmental services, Social influence

Zhanli Sun, Daniel MüLler

2013-07-01T23:59:59.000Z

142

Wind resource assessment with a mesoscale non-hydrostatic model  

E-Print Network (OSTI)

Wind resource assessment with a mesoscale non- hydrostatic model Vincent Guénard, Center for Energy is developed for assessing the wind resource and its uncertainty. The work focuses on an existing wind farm mast measurements. The wind speed and turbulence fields are discussed. It is shown that the k

Paris-Sud XI, Université de

143

Performance model assessment for multi-junction concentrating photovoltaic systems.  

DOE Green Energy (OSTI)

Four approaches to modeling multi-junction concentrating photovoltaic system performance are assessed by comparing modeled performance to measured performance. Measured weather, irradiance, and system performance data were collected on two systems over a one month period. Residual analysis is used to assess the models and to identify opportunities for model improvement. Large photovoltaic systems are typically developed as projects which supply electricity to a utility and are owned by independent power producers. Obtaining financing at favorable rates and attracting investors requires confidence in the projected energy yield from the plant. In this paper, various performance models for projecting annual energy yield from Concentrating Photovoltaic (CPV) systems are assessed by comparing measured system output to model predictions based on measured weather and irradiance data. The results are statistically analyzed to identify systematic error sources.

Stein, Joshua S.; Riley, Daniel M.; McConnell, Robert. (Amonix, Inc., Seal Beach, CA); Sahm, Aaron (University of Nevada, Las Vegas, NV); Crawford, Clark (Amonix, Inc., Seal Beach, CA); King, David L.; Cameron, Christopher P.; Foresi, James S. (Emcore, Inc., Albuquerque, NM)

2010-03-01T23:59:59.000Z

144

Co-benefits Risk Assessment (COBRA) Screening Model | Open Energy  

Open Energy Info (EERE)

Co-benefits Risk Assessment (COBRA) Screening Model Co-benefits Risk Assessment (COBRA) Screening Model Jump to: navigation, search Tool Summary Name: Co-benefits Risk Assessment (COBRA) Screening Model Agency/Company /Organization: United States Environmental Protection Agency Sector: Climate Complexity/Ease of Use: Moderate Website: www.epa.gov/statelocalclimate/resources/cobra.html Cost: Free Related Tools Tool for Selecting CDM Methods & Technologies Modular Applied General Equilibrium Tool (MAGNET) COMMUTER Model ... further results Find Another Tool FIND DEVELOPMENT IMPACTS ASSESSMENT TOOLS Automated tool that can be downloaded from the website. Converts emissions reductions into air quality improvements, estimates annual adverse health impacts avoided, and monetizes the value of these. Approach COBRA converts emissions reductions into air quality improvements, and

145

Modeling of Molten Salt Mixtures: Thermodynamic Assessment of ...  

Science Conference Proceedings (OSTI)

Presentation Title, Modeling of Molten Salt Mixtures: Thermodynamic Assessment of CeBr3 and MBr-CeBr3 Systems (M=Li, Na, K, Rb). Author(s), Yue Wu, ...

146

Numerical modelling of dynamical interaction between seismic radiation and near-surface geological structures: a parallel approach  

Science Conference Proceedings (OSTI)

We investigate a faster and easier way to parallelise seismological codes able to simulate the dynamical interaction between seismic radiation and near-surface geological structures. This is important in assessing strong ground motion, in the mitigation ... Keywords: HPF, numerical modelling, openMP, parallel computing, seismic site effects

A. Caserta; V. Ruggiero; P. Lanucara

2002-11-01T23:59:59.000Z

147

Abstract--A stochastic dynamic programming hydrothermal dispatch model to simulate a bid-based market is  

E-Print Network (OSTI)

on dynamic programming that optimizes and validates the bid prices strategies for each power plant in a hydro-thermal, and simulating them as if they were a single power plant. In a hydro-thermal system as the one simulated several plants. Emphasis is given to hydro reservoir modeling and to the assessment of their market power

Catholic University of Chile (Universidad Católica de Chile)

148

A dynamical model for pion electroproduction on the nucleon  

E-Print Network (OSTI)

We develop a Lorenz- and gauge-invariant dynamical model for pion electroproduction in the resonance region. The model is based on solving of the Salpeter (instantaneous) equation for the pion-nucleon interaction with a hadron-exchange potential. We find that the one-particle-exchange kernel of the Salpeter equation for pion electroproduction develops an unphysical singularity for a finite value of $Q^{2}$. We analyse two methods of dealing with this problem. Results of our model are compared with recent single-polarization data for pion electroproduction.

George L. Caia; Louis E. Wright; Vladimir Pascalutsa

2005-06-02T23:59:59.000Z

149

State reduction dynamics in a simplified QED model  

E-Print Network (OSTI)

A simplified model of quantum electrodynamics involving a charged two-state system interacting with an electromagnetic field mode is examined. By extending the Schrodinger equation to include stochastic and nonlinear terms the dynamical process of quantum state reduction can be represented. A specific choice of modified Schrodinger dynamics is shown to result in stable coherent field states. The two-state system undergoes an induced state reduction to a generalised current state due to its interaction with the field mode. Numerical results are presented demonstrating state reduction dynamics for an initial superposition of two current states. An induced reduction time-scale for the two-state system is derived and confirmed by the numerics.

D. J. Bedingham

2008-08-29T23:59:59.000Z

150

Structural Modeling and Molecular Dynamics Simulation of the Actin Filament  

DOE Green Energy (OSTI)

Actin is a major structural protein of the eukaryotic cytoskeleton and enables cell motility. Here, we present a model of the actin filament (F-actin) that not only incorporates the global structure of the recently published model by Oda et al. but also conserves internal stereochemistry. A comparison is made using molecular dynamics simulation of the model with other recent F-actin models. A number of structural determents such as the protomer propeller angle, the number of hydrogen bonds, and the structural variation among the protomers are analyzed. The MD comparison is found to reflect the evolution in quality of actin models over the last 6 years. In addition, simulations of the model are carried out in states with both ADP or ATP bound and local hydrogen-bonding differences characterized.

Splettstoesser, Thomas [University of Heidelberg; Holmes, Kenneth [Max Planck Institute, Heidelberg, Germany; Noe, Frank [DFG Research Center Matheon, FU Berlin, Germany; Smith, Jeremy C [ORNL

2011-01-01T23:59:59.000Z

151

Modelling Mediterranean landscape succession-disturbance dynamics: A landscape fire-succession model  

Science Conference Proceedings (OSTI)

We present a spatially explicit Landscape Fire-Succession Model (LFSM) developed to represent Mediterranean Basin landscapes and capable of integrating modules and functions that explicitly represent human activity. Plant-functional types are used to ... Keywords: Landscape fire-succession model, Mediterranean landscape, Pattern-oriented modelling, Succession-disturbance dynamics, Wildfire regime

James D. A. Millington; John Wainwright; George L. W. Perry; Raul Romero-Calcerrada; Bruce D. Malamud

2009-10-01T23:59:59.000Z

152

Dynamic model and estimation of the future eutrophication for the Lake Prespa  

Science Conference Proceedings (OSTI)

This paper presents a new computing analysis, based on Matlab Simulink, how to build a dynamic model for aquatic surface water bodies in our case the Lake Prespa. The dynamic model, which is more complex than the other models, it involves equation that ... Keywords: Lake Prespa, dynamic model, eutrophication, phosphorus concentration, scenario ca, scenario cc

Kosta Mitreski; Andreja Naumoski

2007-05-01T23:59:59.000Z

153

Software reliability assessment via fuzzy logic model  

Science Conference Proceedings (OSTI)

Recently in software engineering it became of great importance to be able to reason about non functional characteristics of software. This holds for a large variety of application areas like embedded and safety-critical software systems as well as service-oriented ... Keywords: fuzzy logic, fuzzy models, service oriented software systems, software reliability

Olga Georgieva; Aleksandar Dimov

2011-06-01T23:59:59.000Z

154

Simulink models are also software: modularity assessment  

Science Conference Proceedings (OSTI)

In automotive industry, more and more complex electronics and software systems are being developed to enable the innovation and to decrease costs. Besides the complex multimedia, comfort, and safety systems of conventional vehicles, automotive companies ... Keywords: automotive architectural quality, modularity, quality metrics, simulink model

Yanja Dajsuren; Mark G.J. van den Brand; Alexander Serebrenik; Serguei Roubtsov

2013-06-01T23:59:59.000Z

155

Dynamic Absorption Model for Off-Gas Separation  

Science Conference Proceedings (OSTI)

Modeling and simulations will aid in the future design of U.S. advanced reprocessing plants for the recovery and recycle of actinides in used nuclear fuel. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, a rate based, dynamic absorption model is being developed in gPROMS software. Inputs include liquid and gas stream constituents, column properties, liquid and gas phase reactions, number of stages, and inlet conditions. It simulates multiple component absorption with countercurrent flow and accounts for absorption by mass transfer and chemical reaction. The assumption of each stage being a discrete well-mixed entity was made. Therefore, the model is solved stagewise. The simulation outputs component concentrations in both phases as a function of time from which the rate of absorption is determined. Temperature of both phases is output as a function of time also. The model will be used able to be used as a standalone model in addition to in series with other off-gas separation unit operations. The current model is being generated based on NOx absorption; however, a future goal is to develop a CO2 specific model. The model will have the capability to be modified for additional absorption systems. The off-gas models, both adsorption and absorption, will be made available via the server or web for evaluation by customers.

Veronica J. Rutledge

2011-07-01T23:59:59.000Z

156

Utility of Social Modeling for Proliferation Assessment - Preliminary Findings  

Science Conference Proceedings (OSTI)

Often the methodologies for assessing proliferation risk are focused around the inherent vulnerability of nuclear energy systems and associated safeguards. For example an accepted approach involves ways to measure the intrinsic and extrinsic barriers to potential proliferation. This paper describes preliminary investigation into non-traditional use of social and cultural information to improve proliferation assessment and advance the approach to assessing nuclear material diversion. Proliferation resistance assessment, safeguard assessments and related studies typically create technical information about the vulnerability of a nuclear energy system to diversion of nuclear material. The purpose of this research project is to find ways to integrate social information with technical information by explicitly considering the role of culture, groups and/or individuals to factors that impact the possibility of proliferation. When final, this work is expected to describe and demonstrate the utility of social science modeling in proliferation and proliferation risk assessments.

Coles, Garill A.; Gastelum, Zoe N.; Brothers, Alan J.; Thompson, Sandra E.

2009-07-16T23:59:59.000Z

157

Stochastic kinetic models: Dynamic independence, modularity and graphs  

E-Print Network (OSTI)

The dynamic properties and independence structure of stochastic kinetic models (SKMs) are analyzed. An SKM is a highly multivariate jump process used to model chemical reaction networks, particularly those in biochemical and cellular systems. We identify SKM subprocesses with the corresponding counting processes and propose a directed, cyclic graph (the kinetic independence graph or KIG) that encodes the local independence structure of their conditional intensities. Given a partition $[A,D,B]$ of the vertices, the graphical separation $A\\perp B|D$ in the undirected KIG has an intuitive chemical interpretation and implies that $A$ is locally independent of $B$ given $A\\cup D$. It is proved that this separation also results in global independence of the internal histories of $A$ and $B$ conditional on a history of the jumps in $D$ which, under conditions we derive, corresponds to the internal history of $D$. The results enable mathematical definition of a modularization of an SKM using its implied dynamics. Gra...

Bowsher, Clive G

2010-01-01T23:59:59.000Z

158

Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics  

Alternative Fuels and Advanced Vehicles Data Center (EERE)

Lessons Learned from Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics C. Welch Technical Report NREL/TP-540-39446 February 2006 Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics C. Welch Prepared under Task Nos. HS04.2000 and HS06.1002 Technical Report NREL/TP-540-39446 February 2006 National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov Operated for the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy by Midwest Research Institute * Battelle Contract No. DE-AC36-99-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any

159

Conceptual adsorption models and open issues pertaining to performance assessment  

SciTech Connect

Recently several articles have been published that question the appropriateness of the distribution coefficient, Rd, concept to quantify radionuclide migration. Several distinct issues are raised by various critics. In this paper I provide some perspective on issues surrounding the modeling of nuclide retardation. The first section defines adsorption terminology and discusses various adsorption processes. The next section describes five commonly used adsorption conceptual models, specifically emphasizing what attributes that affect adsorption are explicitly accommodated in each model. I also review efforts to incorporate each adsorption model into performance assessment transport computer codes. The five adsorption conceptual models are (1) the constant Rd model, (2) the parametric Rd model, (3) isotherm adsorption models, (4) mass-action adsorption models, and (5) surface-complexation with electrostatics models. The final section discusses the adequacy of the distribution ratio concept, the adequacy of transport calculations that rely on constant retardation factors and the status of incorporating sophisticated adsorption models into transport codes.

Serne, R.J.

1991-10-01T23:59:59.000Z

160

Climate impacts of bioenergy: Inclusion of carbon cycle and albedo dynamics in life cycle impact assessment  

SciTech Connect

Life cycle assessment (LCA) can be an invaluable tool for the structured environmental impact assessment of bioenergy product systems. However, the methodology's static temporal and spatial scope combined with its restriction to emission-based metrics in life cycle impact assessment (LCIA) inhibits its effectiveness at assessing climate change impacts that stem from dynamic land surface-atmosphere interactions inherent to all biomass-based product systems. In this paper, we focus on two dynamic issues related to anthropogenic land use that can significantly influence the climate impacts of bioenergy systems: i) temporary changes to the terrestrial carbon cycle; and ii) temporary changes in land surface albedo-and illustrate how they can be integrated within the LCA framework. In the context of active land use management for bioenergy, we discuss these dynamics and their relevancy and outline the methodological steps that would be required to derive case-specific biogenic CO{sub 2} and albedo change characterization factors for inclusion in LCIA. We demonstrate our concepts and metrics with application to a case study of transportation biofuel sourced from managed boreal forest biomass in northern Europe. We derive GWP indices for three land management cases of varying site productivities to illustrate the importance and need to consider case- or region-specific characterization factors for bioenergy product systems. Uncertainties and limitations of the proposed metrics are discussed. - Highlights: Black-Right-Pointing-Pointer A method for including temporary surface albedo and carbon cycle changes in Life Cycle Impact Assessment (LCIA) is elaborated. Black-Right-Pointing-Pointer Concepts are applied to a single bioenergy case whereby a range of feedstock productivities are shown to influence results. Black-Right-Pointing-Pointer Results imply that case- and site-specific characterization factors can be essential for a more informed impact assessment. Black-Right-Pointing-Pointer Uncertainties and limitations of the proposed methodologies are elaborated.

Bright, Ryan M., E-mail: ryan.m.bright@ntnu.no; Cherubini, Francesco; Stromman, Anders H.

2012-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Dynamic modeling efforts for system interface studies for nuclear hydrogen production.  

DOE Green Energy (OSTI)

System interface studies require not only identifying economically optimal equipment configurations, which involves studying mainly full power steady-state operation, but also assessing the operability of a design during load change and startup and assessing safety-related behavior during upset conditions. This latter task is performed with a dynamic simulation code. This report reviews the requirements of such a code. It considers the types of transients that will need to be simulated, the phenomena that will be present, the models best suited for representing the phenomena, and the type of numerical solution scheme for solving the models to obtain the dynamic response of the combined nuclear-hydrogen plant. Useful insight into plant transient behavior prior to running a dynamics code is obtained by some simple methods that take into account component time constants and energy capacitances. Methods for determining reactor stability, plant startup time, and temperature response during load change, and tripping of the reactor are described. Some preliminary results are presented.

Vilim, R. B.; Nuclear Engineering Division

2007-08-15T23:59:59.000Z

162

Modeling the dynamic crush of impact mitigating materials  

DOE Green Energy (OSTI)

Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence the dynamic mechanical behavior of crushable materials. One issue we addressed was that no single existing model would account for the entire gambit of constitutive features which are important for crushable materials. Thus, we describe the implementation and use of an additional material model which attempts to provide a more comprehensive model of the mechanics of crushable material behavior. This model combines features of the pre-existing DYNA models and incorporates some new features as well in an invariant large-strain formulation. In addition to examining the behavior of a unit cell in uniaxial compression, two cases were chosen to evaluate the capabilities and accuracy of the various material models in DYNA. In the first case, a model for foam filled box beams was developed and compared to test data from a 4-point bend test. The model was subsequently used to study its effectiveness in energy absorption in an aluminum extrusion, spaceframe, vehicle chassis. The second case examined the response of the AT-400A shipping container and the performance of the overpack material during accident environments selected from 10CFR71 and IAEA regulations.

Logan, R.W.; McMichael, L.D.

1995-05-12T23:59:59.000Z

163

A Dissipative-Particle-Dynamics Model for Simulating Dynamics of Charged Colloid  

E-Print Network (OSTI)

A mesoscopic colloid model is developed in which a spherical colloid is represented by many interacting sites on its surface. The hydrodynamic interactions with thermal fluctuations are taken accounts in full using Dissipative Particle Dynamics, and the electrostatic interactions are simulated using Particle-Particle-Particle Mesh method. This new model is applied to investigate the electrophoretic mobility of a charged colloid under an external electric field, and the influence of salt concentration and colloid charge are systematically studied. The simulation results show good agreement with predictions from the electrokinetic theory.

Jiajia Zhou; Friederike Schmid

2013-11-05T23:59:59.000Z

164

Coping with uncertain dynamics in visual tracking : redundant state models and discrete search methods  

E-Print Network (OSTI)

A model of the world dynamics is a vital part of any tracking algorithm. The observed world can exhibit multiple complex dynamics at different spatio-temporal scales. Faithfully modeling all motion constraints in a ...

Taycher, Leonid

2006-01-01T23:59:59.000Z

165

Workshop on Carbon Sequestration Science - Modeling and Integrated Assessment  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling and Integrated Modeling and Integrated Assessment Howard Herzog MIT Energy Laboratory May 24, 2001 Economic Assessments * Engineering analysis of CO 2 separation and capture * Economic modeling/ integrated assessment of carbon capture and sequestration * Comparison on equal basis of the major sequestration options Economic Modeling Motivation * When might carbon capture and sequestration (CCS) become competitive? * What is its potential scale? * Which technologies look most promising? . . . . And when? * How to see the potential in a general market context? Detailed Reference *Sean Biggs Thesis: S Biggs, S. D., "Sequestering Carbon from Power Plants: The Jury is Still Out," M.I.T. Masters Thesis, (2000). S http://sequestration.mit.edu/pdf/SeanBiggs.pdf What Determines Competitiveness?

166

Assessment of boreal forest historical C dynamics in Yukon River Basin: relative roles of warming and fire regime change  

Science Conference Proceedings (OSTI)

Carbon (C) dynamics of boreal forest ecosystems have substantial implications for efforts to mitigate the rise of atmospheric CO2 and may be substantially influenced by warming and changing wildfire regimes. In this study we applied a large-scale ecosystem model that included dynamics of organic soil horizons and soil organic matter characteristics of multiple pools to assess forest C stock changes of the Yukon River Basin (YRB) in Alaska, USA, and Canada from 1960 through 2006, a period characterized by substantial climate warming and increases in wildfire. The model was calibrated for major forests with data from long-term research sites and evaluated using a forest inventory database. The regional assessment indicates that forest vegetation C storage increased by 46 Tg C, but that total soil C storage did not change appreciably during this period. However, further analysis suggests that C has been continuously lost from the mineral soil horizon since warming began in the 1970s, but has increased in the amorphous organic soil horizon. Based on a factorial experiment, soil C stocks would have increased by 158 Tg C if the YRB had not undergone warming and changes in fire regime. The analysis also identified that warming and changes in fire regime were approximately equivalent in their effects on soil C storage, and interactions between these two suggests that the loss of organic horizon thickness associated with increases in wildfire made deeper soil C stocks more vulnerable to loss via decomposition. Subbasin analyses indicate that C stock changes were primarily sensitive to the fraction of burned forest area within each subbasin and that boreal forest ecosystems in the YRB are currently transitioning from being sinks to sources at ;0.7% annual area burned. We conclude that it is important for international mitigation efforts focused on controlling atmospheric CO2 to consider how climate warming and changes in fire regime may concurrently affect the CO2 sink strength of boreal forests. It is also important for large-scale biogeochemical and earth system models to include organic soil dynamics in applications to assess regional C dynamics of boreal forests responding to warming and changes in fire regime.

Yuan, Fengming [ORNL; Yi, Shuhua [Cold and Arid Regions Environmental and Engineering Research Institute, CAS; McGuire, A. David [University of Alaska; Johnson, Kristopher D [University of Alaska, Fairbanks; Liang, Jingjing [University of Alaska, Fairbanks; Harden, Jennifer [USGS, Menlo Park, CA; Kasischke, Eric S. [University of Maryland, College Park; Kurz, Werner [Canadian Forest Service

2012-01-01T23:59:59.000Z

167

Nuclear Hybrid Energy System Modeling: RELAP5 Dynamic Coupling Capabilities  

SciTech Connect

The nuclear hybrid energy systems (NHES) research team is currently developing a dynamic simulation of an integrated hybrid energy system. A detailed simulation of proposed NHES architectures will allow initial computational demonstration of a tightly coupled NHES to identify key reactor subsystem requirements, identify candidate reactor technologies for a hybrid system, and identify key challenges to operation of the coupled system. This work will provide a baseline for later coupling of design-specific reactor models through industry collaboration. The modeling capability addressed in this report focuses on the reactor subsystem simulation.

Piyush Sabharwall; Nolan Anderson; Haihua Zhao; Shannon Bragg-Sitton; George Mesina

2012-09-01T23:59:59.000Z

168

Scale-Free model for governing universe dynamics  

E-Print Network (OSTI)

We investigate the effects of scale-free model on cosmology, providing, in this way, a statistical background in the framework of general relativity. In order to discuss properties and time evolution of some relevant universe dynamical parameters (cosmographic parameters), such as $H(t)$ (Hubble parameter), $q(t)$ (deceleration parameter), $j(t)$ (jerk parameter) and $s(t)$ (snap parameter), which are well re-defined in the framework of scale-free model, we analyze a comparison between WMAP data. Hence the basic purpose of the work is to consider this statistical interpretation of mass distribution of universe, in order to have a mass density $\\rho$ dynamics, not inferred from Friedmann equations, via scale factor $a(t)$. This model, indeed, has been used also to explain a possible origin and a viable explanation of cosmological constant, which assumes a statistical interpretation without the presence of extended theories of gravity; hence the problem of dark energy could be revisited in the context of a classical probability distribution of mass, which is, in particular, for the scale-free model, $P(k)\\sim k^{-\\gamma}$, with $2<\\gamma<3$. The $\\Lambda$CDM model becomes, with these considerations, a consequence of the particular statistics together with the use of general relativity.

Orlando Luongo; Carmine Autieri

2009-02-21T23:59:59.000Z

169

Modeling space plasma dynamics with anisotropic Kappa distributions  

E-Print Network (OSTI)

Space plasmas are collisionpoor and kinetic effects prevail leading to wave fluctuations, which transfer the energy to small scales: wave-particle interactions replace collisions and enhance dispersive effects heating particles and producing suprathermal populations observed at any heliospheric distance in the solar wind. At large distances collisions are not efficient, and the selfgenerated instabilities constrain the solar wind anisotropy including the thermal core and the suprathermal components. The generalized power-laws of Kappa-type are the best fitting model for the observed distributions of particles, and a convenient mathematical tool for modeling their dynamics. But the anisotropic Kappa models are not correlated with the observations leading, in general, to inconsistent effects. This review work aims to reconcile some of the existing Kappa models with the observations.

Lazar, M; Poedts, S; Schlickeiser, R

2012-01-01T23:59:59.000Z

170

Fire models for assessment of nuclear power plant fires  

SciTech Connect

This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plants fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. 17 refs., 6 figs.

Nicolette, V.F.; Nowlen, S.P.

1989-01-01T23:59:59.000Z

171

Computational fluid dynamic modeling of fluidized-bed polymerization reactors  

SciTech Connect

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.

Rokkam, Ram [Ames Laboratory

2012-11-02T23:59:59.000Z

172

Computational Fluid Dynamics Modeling of Atmospheric Flow Applied to Wind Energy Research.  

E-Print Network (OSTI)

??High resolution atmospheric flow modeling using computational fluid dynamics (CFD) has many applications in the wind energy industry. A well designed model can accurately calculate… (more)

Russell, Alan

2009-01-01T23:59:59.000Z

173

A new analytic-adaptive model for EGS assessment, development and  

Open Energy Info (EERE)

new analytic-adaptive model for EGS assessment, development and new analytic-adaptive model for EGS assessment, development and management support Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title A new analytic-adaptive model for EGS assessment, development and management support Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis Project Type / Topic 2 Integrated Chemical, Thermal, Mechanical and Hydrological Modeling Project Description The University of Nevada - Reno (UNR), proposes to develop a new, integrated solution technique for simulating the Thermal, Hydrological, Mechanical, and Chemical (THMC) processes relevant to thermal energy extraction from an Enhanced Geothermal System (EGS). UNR defines the great challenges in numerical modeling as to (1) dealing with flows and transport in the stimulated fractures of the EGS of largely unknown geometry and characteristics; and (2) discovering the best possible cooling fluid circulation solution in the EGS by trial-and-error numerical simulations. The new THMC will have an adaptive, Computational Fluid Dynamics (CFD) component, integrated with the THMC rockmass model in order to match field test signatures, or desired outcomes in design hypothesis test. The project's main hypothesis is that there are new solutions to heat extraction from an as-created, enhanced fracture system of EGS. The project will develop a new THMC simulation model with new capabilities and prove the main hypothesis by and applying it to various EGS designs including emerging concepts, two-phase (steam-gas-liquid) coolant flows in the fracture network, and dynamic, huff-puff operations.

174

Dynamic simulation model for non-supplementary firing triple-pressure heat recovery steam generator  

Science Conference Proceedings (OSTI)

By using the modular modeling method, a real-time dynamic simulation model for the non-supplementary tri-pressure reheat Heat Recovery Steam Generator (HRSG) is developed. On the basis of mass and energy conservation law, the paper discusses the model ... Keywords: HRSG, dynamic model, modular modelling, simulation

Ning Cui; Bing-Shu Wang; Xiang-Yang Gong; Jian-Qiang Gao

2007-10-01T23:59:59.000Z

175

Model for Aggregated Water Heater Load Using Dynamic Bayesian Networks  

Science Conference Proceedings (OSTI)

The transition to the new generation power grid, or “smart grid”, requires novel ways of using and analyzing data collected from the grid infrastructure. Fundamental functionalities like demand response (DR), that the smart grid needs, rely heavily on the ability of the energy providers and distributors to forecast the load behavior of appliances under different DR strategies. This paper presents a new model of aggregated water heater load, based on dynamic Bayesian networks (DBNs). The model has been validated against simulated data from an open source distribution simulation software (GridLAB-D). The results presented in this paper demonstrate that the DBN model accurately tracks the load profile curves of aggregated water heaters under different testing scenarios.

Vlachopoulou, Maria; Chin, George; Fuller, Jason C.; Lu, Shuai; Kalsi, Karanjit

2012-07-19T23:59:59.000Z

176

Dynamic Decision Making for Graphical Models Applied to Oil Exploration  

E-Print Network (OSTI)

We present a framework for sequential decision making in problems described by graphical models. The setting is given by dependent discrete random variables with associated costs or revenues. In our examples, the dependent variables are the potential outcomes (oil, gas or dry) when drilling a petroleum well. The goal is to develop an optimal selection strategy that incorporates a chosen utility function within an approximated dynamic programming scheme. We propose and compare different approximations, from simple heuristics to more complex iterative schemes, and we discuss their computational properties. We apply our strategies to oil exploration over multiple prospects modeled by a directed acyclic graph, and to a reservoir drilling decision problem modeled by a Markov random field. The results show that the suggested strategies clearly improve the simpler intuitive constructions, and this is useful when selecting exploration policies.

Martinelli, Gabriele; Hauge, Ragnar

2012-01-01T23:59:59.000Z

177

The Third State of the Schelling Model of Residential Dynamics  

E-Print Network (OSTI)

The Schelling model of segregation between two groups of residential agents (Schelling 1971; Schelling 1978) reflects the most abstract view of the non-economic forces of residential migrations: be close to people of 'your own'. The model assumes that the residential agent, located in the neighborhood where the fraction of 'friends' is less than a predefined threshold value F, tries to relocate to a neighborhood for which this fraction is above F. It is well known that for the equal groups, depending on F, Schelling's residential pattern converges either to complete integration (random pattern) or segregation. We investigate Schelling model pattern dynamics as dependent on F, the ratio of the group numbers and the size of the neighborhood and demonstrate that the traditional integrate-segregate dichotomy is incomplete. In case of unequal groups, there exists the wide interval of the F-values that entails the third persistent residential pattern, in which part of the majority population segregates, while the r...

Benenson, Itzhak

2009-01-01T23:59:59.000Z

178

Interactive computational models of particle dynamics using virtual reality  

DOE Green Energy (OSTI)

An increasing number of industrial applications rely on computational models to reduce costs in product design, development, and testing cycles. Here, the authors discuss an interactive environment for the visualization, analysis, and modification of computational models used in industrial settings. In particular, they focus on interactively placing massless, massed, and evaporating particulate matter in computational fluid dynamics applications.they discuss the numerical model used to compute the particle pathlines in the fluid flow for display and analysis. They briefly describe the toolkits developed for vector and scalar field visualization, interactive particulate source placement, and a three-dimensional GUI interface. This system is currently used in two industrial applications, and they present the tools in the context of these applications. They summarize the current state of the project and offer directions for future research.

Canfield, T.; Diachin, D.; Freitag, L.; Heath, D.; Herzog, J. [Argonne National Lab., IL (United States); Michels, W. [Nalco Fuel Tech, Naperville, IL (United States)

1996-12-31T23:59:59.000Z

179

Assessing the RELAPS-3D Heat Conduction Enclosure Model  

SciTech Connect

Three heat conduction problems that have exact solutions are modeled with RELAP5-3D using the conduction enclosure model. These comparisons are designed to be used in the RELAP5-3D development assessment scheduled to be completed in 2009. It is shown that with proper input choices and adequate model detail the exact solutions can be matched. In addition, this analysis identified an error and the required correction in the cylindrical and spherical heat conductor models in RELAP5-3D which will be corrected in a future version of RELAP5-3D.

McCann, Larry D.

2008-09-30T23:59:59.000Z

180

Atomistic modeling of metal surfaces under electric fields: direct coupling of electric fields to a molecular dynamics algorithm  

E-Print Network (OSTI)

The effect of electric fields on metal surfaces is fairly well studied, resulting in numerous analytical models developed to understand the mechanisms of ionization of surface atoms observed at very high electric fields, as well as the general behavior of a metal surface in this condition. However, the derivation of analytical models does not include explicitly the structural properties of metals, missing the link between the instantaneous effects owing to the applied field and the consequent response observed in the metal surface as a result of an extended application of an electric field. In the present work, we have developed a concurrent electrodynamic–molecular dynamic model for the dynamical simulation of an electric-field effect and subsequent modification of a metal surface in the framework of an atomistic molecular dynamics (MD) approach. The partial charge induced on the surface atoms by the electric field is assessed by applying the classical Gauss law. The electric forces acting on the partially...

Djurabekova, Flyura; Pohjonen, Aarne; Nordlund, Kai

2011-01-01T23:59:59.000Z

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181

Assessing Impacts of Climate Change on Forests: The State of Biological Modeling  

DOE R&D Accomplishments (OSTI)

Models that address the impacts to forests of climate change are reviewed by four levels of biological organization: global, regional or landscape, community, and tree. The models are compared as to their ability to assess changes in greenhouse gas flux, land use, maps of forest type or species composition, forest resource productivity, forest health, biodiversity, and wildlife habitat. No one model can address all of these impacts, but landscape transition models and regional vegetation and land-use models consider the largest number of impacts. Developing landscape vegetation dynamics models of functional groups is suggested as a means to integrate the theory of both landscape ecology and individual tree responses to climate change. Risk assessment methodologies can be adapted to deal with the impacts of climate change at various spatial and temporal scales. Four areas of research development are identified: (1) linking socioeconomic and ecologic models, (2) interfacing forest models at different scales, (3) obtaining data on susceptibility of trees and forest to changes in climate and disturbance regimes, and (4) relating information from different scales.

Dale, V. H.; Rauscher, H. M.

1993-04-06T23:59:59.000Z

182

Assessing impacts of climate change on forests: The state of biological modeling  

Science Conference Proceedings (OSTI)

Models that address the impacts to forests of climate change are reviewed by four levels of biological organization: global, regional or landscape, community, and tree. The models are compared as to their ability to assess changes in greenhouse gas flux, land use, maps of forest type or species composition, forest resource productivity, forest health, biodiversity, and wildlife habitat. No one model can address all of these impacts, but landscape transition models and regional vegetation and land-use models consider the largest number of impacts. Developing landscape vegetation dynamics models of functional groups is suggested as a means to integrate the theory of both landscape ecology and individual tree responses to climate change. Risk assessment methodologies can be adapted to deal with the impacts of climate change at various spatial and temporal scales. Four areas of research development are identified: (1) linking socioeconomic and ecologic models, (2) interfacing forest models at different scales, (3) obtaining data on susceptibility of trees and forest to changes in climate and disturbance regimes, and (4) relating information from different scales.

Dale, V.H. [Oak Ridge National Lab., TN (United States); Rauscher, H.M. [Forest Service, Grand Rapids, MI (United States). North Central Forest Experiment Station

1993-04-06T23:59:59.000Z

183

Dynamic volume vs respiratory correlated 4DCT for motion assessment in radiation therapy simulation  

SciTech Connect

Purpose: Conventional (i.e., respiratory-correlated) 4DCT exploits the repetitive nature of breathing to provide an estimate of motion; however, it has limitations due to binning artifacts and irregular breathing in actual patient breathing patterns. The aim of this work was to evaluate the accuracy and image quality of a dynamic volume, CT approach (4D{sub vol}) using a 320-slice CT scanner to minimize these limitations, wherein entire image volumes are acquired dynamically without couch movement. This will be compared to the conventional respiratory-correlated 4DCT approach (RCCT). Methods: 4D{sub vol} CT was performed and characterized on an in-house, programmable respiratory motion phantom containing multiple geometric and morphological ''tumor'' objects over a range of regular and irregular patient breathing traces obtained from 3D fluoroscopy and compared to RCCT. The accuracy of volumetric capture and breathing displacement were evaluated and compared with the ground truth values and with the results reported using RCCT. A motion model was investigated to validate the number of motion samples needed to obtain accurate motion probability density functions (PDF). The impact of 4D image quality on this accuracy was then investigated. Dose measurements using volumetric and conventional scan techniques were also performed and compared. Results: Both conventional and dynamic volume 4DCT methods were capable of estimating the programmed displacement of sinusoidal motion, but patient breathing is known to not be regular, and obvious differences were seen for realistic, irregular motion. The mean RCCT amplitude error averaged at 4 mm (max. 7.8 mm) whereas the 4D{sub vol} CT error stayed below 0.5 mm. Similarly, the average absolute volume error was lower with 4D{sub vol} CT. Under irregular breathing, the 4D{sub vol} CT method provides a close description of the motion PDF (cross-correlation 0.99) and is able to track each object, whereas the RCCT method results in a significantly different PDF from the ground truth, especially for smaller tumors (cross-correlation ranging between 0.04 and 0.69). For the protocols studied, the dose measurements were higher in the 4D{sub vol} CT method (40%), but it was shown that significant mAs reductions can be achieved by a factor of 4-5 while maintaining image quality and accuracy. Conclusions: 4D{sub vol} CT using a scanner with a large cone-angle is a promising alternative for improving the accuracy with which respiration-induced motion can be characterized, particularly for patients with irregular breathing motion. This approach also generates 4DCT image data with a reduced total scan time compared to a RCCT scan, without the need for image binning or external respiration signals within the 16 cm scan length. Scan dose can be made comparable to RCCT by optimization of the scan parameters. In addition, it provides the possibility of measuring breathing motion for more than one breathing cycle to assess stability and obtain a more accurate motion PDF, which is currently not feasible with the conventional RCCT approach.

Coolens, Catherine; Bracken, John; Driscoll, Brandon; Hope, Andrew; Jaffray, David [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada); Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3S2 (Canada) and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

2012-05-15T23:59:59.000Z

184

A model for the ATW target region fluid dynamics  

SciTech Connect

In the Los Alamos National Laboratory's concept for the accelerator transmutation of waste (ATW), a lead-bismuth eutectic has been chosen as a spallation target for the proton beam. Because of the high local heat fluxes anticipated, the target is in liquid form to facilitate heat removal. The upper boundary of the target region is a hard vacuum. The primary purpose of the analysis is to determine the location of the flow boundary based on the target design parameters. This method of analysis should prove to be useful for performing preliminary scoping and design of the ATW target region's fluid dynamics. Eventually, this model should be tested against experimental data.

Rider, W.J.; Cappiello, M.W. (Los Alamos National Lab., NM (United States))

1991-01-01T23:59:59.000Z

185

Dynamic Properties of Molecular Motors in Burnt-Bridge Models  

E-Print Network (OSTI)

Dynamic properties of molecular motors that fuel their motion by actively interacting with underlying molecular tracks are studied theoretically via discrete-state stochastic ``burnt-bridge'' models. The transport of the particles is viewed as an effective diffusion along one-dimensional lattices with periodically distributed weak links. When an unbiased random walker passes the weak link it can be destroyed (``burned'') with probability p, providing a bias in the motion of the molecular motor. A new theoretical approach that allows one to calculate exactly all dynamic properties of motor proteins, such as velocity and dispersion, at general conditions is presented. It is found that dispersion is a decreasing function of the concentration of bridges, while the dependence of dispersion on the burning probability is more complex. Our calculations also show a gap in dispersion for very low concentrations of weak links which indicates a dynamic phase transition between unbiased and biased diffusion regimes. Theoretical findings are supported by Monte Carlo computer simulations.

Maxim N. Artyomov; Alexander Yu. Morozov; Ekaterina Pronina; Anatoly B. Kolomeisky

2007-05-04T23:59:59.000Z

186

Probabilistic Risk Assessment Compendium of Candidate Consensus Models  

Science Conference Proceedings (OSTI)

This report provides a compendium of candidate consensus models in use in current probabilistic risk assessments (PRAs). The ASME PRA Standard, as modified and endorsed by Regulatory Guide 1.200, establishes that the identification, sensitivity analysis, and documentation of key sources of uncertainties and key assumptions may be reduced in scope if the PRA makes use of consensus models to implement the supporting requirements. As part of the process of treating the uncertainties associated with a risk-...

2006-08-16T23:59:59.000Z

187

Biosphere Modeling and Dose Assessment for Yucca Mountain  

Science Conference Proceedings (OSTI)

This report develops a biosphere model appropriate for use in calculating doses to hypothetical individuals living in the far future in the vicinity of Yucca Mountain, Nevada. Doses are assumed to arise from potential releases from a spent fuel and high-level radioactive waste (HLW) disposal facility located beneath Yucca Mountain. The model provides guidance on approaches to dealing with the biosphere appropriate for site suitability and licensing assessments.

1996-12-31T23:59:59.000Z

188

How reliable are Finite-Size Lyapunov Exponents for the assessment of ocean dynamics?  

E-Print Network (OSTI)

Much of atmospheric and oceanic transport is associated with coherent structures. Lagrangian methods are emerging as optimal tools for their identification and analysis. An important Lagrangian technique which is starting to be widely used in oceanography is that of Finite-Size Lyapunov Exponents (FSLEs). Despite this growing relevance there are still many open questions concerning the reliability of the FSLEs in order to analyse the ocean dynamics. In particular, it is still unclear how robust they are when confronted with real data. In this paper we analyze the effect on this Lagrangian technique of the two most important effects when facing real data, namely noise and dynamics of unsolved scales. Our results, using as a benchmarch data from a primitive numerical model of the Mediterranean Sea, show that even when some dynamics is missed the FSLEs results still give an accurate picture of the oceanic transport properties.

Ismael Hernández-Carrasco; Emilio Hernández-García; Cristóbal López; Antonio Turiel

2010-09-13T23:59:59.000Z

189

Bootstrapping to Assess and Improve Atmospheric Prediction Models  

Science Conference Proceedings (OSTI)

Bootstrapping is a simple technique typically used to assess accuracy of estimates of model parameters by using simple plug-in principles and replacing sometimes unwieldy theory by computer simulation. Common uses include variance estimation and confidence ... Keywords: CART, bootstrap, classification, hurricanes, instability, supervised learning, weather data

J. Sunil Rao

2000-04-01T23:59:59.000Z

190

Groundwater Impacts of Radioactive Wastes and Associated Environmental Modeling Assessment  

Science Conference Proceedings (OSTI)

This article provides a review of the major sources of radioactive wastes and their impacts on groundwater contamination. The review discusses the major biogeochemical processes that control the transport and fate of radionuclide contaminants in groundwater, and describe the evolution of mathematical models designed to simulate and assess the transport and transformation of radionuclides in groundwater.

Ma, Rui; Zheng, Chunmiao; Liu, Chongxuan

2012-11-01T23:59:59.000Z

191

Improving Health Care Management Through the Use of Dynamic Simulation Modeling and Health Information Systems  

Science Conference Proceedings (OSTI)

To better understand the performance of hospital operations in response to IT-enabled improvement, this paper reports the results of a system dynamics model designed to improve core medical processes. Utilizing system dynamics modeling and emerging Health ... Keywords: Health Information Systems, Heath Care, Hospital Management, Process Improvement, System Dynamics

Daniel Goldsmith; Michael Siegel

2012-01-01T23:59:59.000Z

192

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model  

E-Print Network (OSTI)

Time Series Forecasting for Dynamic Environments: the DyFor Genetic Program Model Neal Wagner programming (GP) to the task of forecasting with favorable results. However, these studies, like those "dynamic" GP model that is specifically tailored for forecasting in non-static environments. This Dynamic

Michalewicz, Zbigniew

193

Dynamic Model of Hydrogen in GaN  

NLE Websites -- All DOE Office Websites (Extended Search)

Dynamic Model of Hydrogen in GaN by S. M. Myers and A. F. Wright Motivation-Hydrogen is incorporated into p-type GaN during MOCVD growth, producing highly stable passivation of the Mg acceptors. Complete acceptor activation by thermal H release requires temperatures that threaten material integrity, prompting compromises in device processing. At lower temperatures, forward bias of p-n junctions or electron-beam irradiation produces a metastable, reversible activation without H release. To understand and control such effects, we are developing a mathematical model of H behavior wherein state energies from density-functional theory are employed in diffusion-reaction equations. Previously, we used the greatly simplifying assumptions of local equilibrium among states

194

Dynamic chirality in the interacting boson fermion-fermion model  

SciTech Connect

The chiral interpretation of twin bands in odd-odd nuclei was investigated in the interacting boson fermion-fermion model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behavior is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the level energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different {beta} and {gamma} fluctuations, induced by the exchange boson-fermion interaction of the interacting boson fermion-fermion model. In both cases the chirality is weak and dynamic.

Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Tonev, D. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); De Angelis, G. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Ventura, A. [Ente per le Nuove tecnologie, l'Energia e l'Ambiente, I-40129 Bologna and Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (Italy)

2008-09-15T23:59:59.000Z

195

Integrated science model for assessment of climate change  

SciTech Connect

Integrated assessment models are intended to represent processes that govern physical, ecological, economic and social systems. This report describes a scientific model relating emissions to global temperature and sea level. This model is intended to be one component of an integrated assessment model which is, of course, much more comprehensive. The model is able to reproduce past changes in CO{sub 2} concentration, global temperature, and sea level. The model is used to estimate the emissions rates required to lead to stabilization of CO{sub 2} at various levels. The model is also used to estimate global temperature rise, the rate of temperature change, and sea level rise driven by IPCC emissions scenarios. The emission of fossil fuel CO{sub 2} is modeled to have the largest long term effect on climate. Results do show the importance of expected changes of trace greenhouse gases other than CO{sub 2} in the near future. Because of the importance of these other trace gases, further work is recommended to more accurately estimate their effects.

Jain, A.K.; Wuebbles, D.J. [Lawrence Livermore National Lab., CA (United States); Kheshgi, H.S. [Exxon Research and Engineering Co., Annandale, NJ (United States)

1994-04-01T23:59:59.000Z

196

Evaluating Aspects of the Community Land and Atmosphere Models (CLM3 and CAM3) Using a Dynamic Global Vegetation Model  

Science Conference Proceedings (OSTI)

The Community Land Model version 3 (CLM3) Dynamic Global Vegetation Model (CLM–DGVM) is used diagnostically to identify land and atmospheric model biases that lead to biases in the simulated vegetation. The CLM–DGVM driven with observed ...

Gordon B. Bonan; Samuel Levis

2006-06-01T23:59:59.000Z

197

Choose inter-element coupling to preserve self-adjoint dynamics in multiscale modelling and computation  

Science Conference Proceedings (OSTI)

Consider the macroscale modelling of microscale spatio-temporal dynamics. Here we develop an approach to ensure coarse scale discrete models preserve important self-adjoint properties of the microscale dynamics. The first part explores the discrete modelling ... Keywords: Centre manifold theory, Closure, Macroscale discretisation, Multiscale modelling

A. J. Roberts

2010-10-01T23:59:59.000Z

198

CAM-SE: A scalable spectral element dynamical core for the Community Atmosphere Model  

Science Conference Proceedings (OSTI)

The Community Atmosphere Model (CAM) version 5 includes a spectral element dynamical core option from NCAR's High-Order Method Modeling Environment. It is a continuous Galerkin spectral finite-element method designed for fully unstructured quadrilateral ... Keywords: atmospheric modeling, dynamical core, global circulation model, parallel scalability, spectral elements

John M. Dennis; Jim Edwards; Katherine J. Evans; Oksana Guba; Peter H. Lauritzen; Arthur A. Mirin; Amik St-Cyr; Mark A. Taylor; Patrick H. Worley

2012-02-01T23:59:59.000Z

199

Position Paper: A general framework for Dynamic Emulation Modelling in environmental problems  

Science Conference Proceedings (OSTI)

Emulation modelling is an effective way of overcoming the large computational burden associated with the process-based models traditionally adopted by the environmental modelling community. An emulator is a low-order, computationally efficient model ... Keywords: Dynamic emulation modelling, Metamodelling, Model complexity, Model reduction, Process-based models, Response surfaces

A. Castelletti; S. Galelli; M. Ratto; R. Soncini-Sessa; P. C. Young

2012-06-01T23:59:59.000Z

200

A comparative study of Lotka-Volterra and system dynamics models for simulation of technology industry dynamics  

E-Print Network (OSTI)

Scholars have developed a range of qualitative and quantitative models for generalizing the dynamics of technological innovation and identifying patterns of competition between rivals. This thesis compares two predominant ...

Ünver, Hakk? Özgür

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model  

SciTech Connect

Given a large time-evolving network, how can we model and characterize the temporal behaviors of individual nodes (and network states)? How can we model the behavioral transition patterns of nodes? We propose a temporal behavior model that captures the 'roles' of nodes in the graph and how they evolve over time. The proposed dynamic behavioral mixed-membership model (DBMM) is scalable, fully automatic (no user-defined parameters), non-parametric/data-driven (no specific functional form or parameterization), interpretable (identifies explainable patterns), and flexible (applicable to dynamic and streaming networks). Moreover, the interpretable behavioral roles are generalizable, computationally efficient, and natively supports attributes. We applied our model for (a) identifying patterns and trends of nodes and network states based on the temporal behavior, (b) predicting future structural changes, and (c) detecting unusual temporal behavior transitions. We use eight large real-world datasets from different time-evolving settings (dynamic and streaming). In particular, we model the evolving mixed-memberships and the corresponding behavioral transitions of Twitter, Facebook, IP-Traces, Email (University), Internet AS, Enron, Reality, and IMDB. The experiments demonstrate the scalability, flexibility, and effectiveness of our model for identifying interesting patterns, detecting unusual structural transitions, and predicting the future structural changes of the network and individual nodes.

Rossi, R; Gallagher, B; Neville, J; Henderson, K

2011-11-11T23:59:59.000Z

202

Performance of Three Mode-Meter Block-Processing Algorithms for Automated Dynamic Stability Assessment  

SciTech Connect

The frequency and damping of electromechanical modes offer considerable insight into the dynamic stability properties of a power system. The performance properties of three block-processing algorithms from the perspective of near real-time automated stability assessment are demonstrated and examined. The algorithms are: the extended modified Yule Walker (YW); extended modified Yule Walker with Spectral analysis (YWS); and numerical state-space subspace system identification(N4SID) algorithm. The YW and N4SID have been introduced in previous publications while the YWS is introduced here. Issues addressed include: stability assessment requirements; automated subset selecting identified modes; using algorithms in an automated format; data assumptions and quality; and expected algorithm estimation performance.

Trudnowski, Daniel J.; Pierre, John W.; Zhou, Ning; Hauer, John F.; Parashar, Manu

2008-05-31T23:59:59.000Z

203

The dynamic North Florida dairy farm model: A user-friendly computerized tool for increasing profits while minimizing N leaching under varying climatic conditions  

Science Conference Proceedings (OSTI)

This paper describes the computer implementation of the Dynamic North Florida Dairy farm model (DyNoFlo Dairy). The DyNoFlo Dairy is a decision support system that integrates nutrient budgeting, crop, and optimization models created to assess nitrogen ... Keywords: Climate, Dairy, Florida, Leaching, Markov chains, Optimization, User friendly

Victor E. Cabrera; Norman E. Breuer; Peter E. Hildebrand; David Letson

2005-11-01T23:59:59.000Z

204

Dynamic Cost-Loss Ratio Decision-making Model with an Autocorrelated Climate Variable  

Science Conference Proceedings (OSTI)

A dynamic decision-making problem is considered involving the use of information about the autocorrelation of a climate variable. Specifically, an infinite horizon, discounted version of the dynamic cost-loss ratio model is treated, in which only ...

Richard W. Katz

1993-01-01T23:59:59.000Z

205

Reduced-order, trajectory piecewise-linear models for nonlinear computational fluid dynamics  

E-Print Network (OSTI)

Computational fluid dynamics (CFD) is now widely used throughout the fluid dynamics community and yields accurate models for problems of interest. However, due to its high computational cost, CFD is limited for some ...

Gratton, David, 1979-

2004-01-01T23:59:59.000Z

206

Fuel cycle assessment: A compendium of models, methodologies, and approaches  

SciTech Connect

The purpose of this document is to profile analytical tools and methods which could be used in a total fuel cycle analysis. The information in this document provides a significant step towards: (1) Characterizing the stages of the fuel cycle. (2) Identifying relevant impacts which can feasibly be evaluated quantitatively or qualitatively. (3) Identifying and reviewing other activities that have been conducted to perform a fuel cycle assessment or some component thereof. (4) Reviewing the successes/deficiencies and opportunities/constraints of previous activities. (5) Identifying methods and modeling techniques/tools that are available, tested and could be used for a fuel cycle assessment.

Not Available

1994-07-01T23:59:59.000Z

207

A Zonally Averaged Ocean Model for the Thermohaline Circulation. Part I: Model Development and Flow Dynamics  

Science Conference Proceedings (OSTI)

A two-dimensional latitude–depth ocean model is developed on the basis of the zonally averaged balance equations of mass, momentum, heat, and salt. Its purpose is to investigate the dynamics and variability of the buoyancy-forced thermohaline ...

Daniel G. Wright; Thomas F. Stocker

1991-12-01T23:59:59.000Z

208

Dynamic modeling of plasma-vapor interactions during plasma disruptions  

SciTech Connect

Intense deposition of energy in short times on fusion reactor components during a plasma disruption may cause severe surface erosion due to ablation of these components. The exact amount of the eroded material is very important to the reactor design and its lifetime. During the plasma deposition, the vaporized wall material will interact with the incoming plasma particles and may shield the rest of the wall from damage. The vapor shielding may then prolong the lifetime of these components and increase the reactor duty cycle. To correctly evaluate the impact of vapor shielding effect a comprehensive model is developed. In this model the dynamic slowing down of the plasma particles, both ions and electrons, with the eroded wall material is established. Different interaction processes between the plasma particles and the ablated material is included. The generated photons radiation source and the transport of this radiation through the vapor to the wall is modeled. Recent experimental data on disruptions is analyzed and compared with model predictions. Vapor shielding may be effective in reducing the overall erosion rate for certain plasma disruption parameters and conditions.

Hassanein, A.; Ehst, D.A.

1992-05-01T23:59:59.000Z

209

Dynamic model of power system operation incorporating load control  

SciTech Connect

Load management has been proposed as a means whereby an electric utility can reduce its requirements for additional generation, transmission, and distribution investments, shift fuel dependency from limited to more abundant energy resources, and improve the efficiency of the electric energy system. There exist, however, serious technological and economic questions which must be answered to define the cost trade-offs between initiating a load management strategy or adding additional capacity to meet the load. One aspect of this complex problem is to determine how the load profile might be modified by the load management option being considered. Towards this end, a model has been developed to determine how a power system with an active load control system should be operated to make the best use of its available resources. The model is capable of handling all types of conventional generating sources including thermal, hydro, and pumped storage units, and most appliances being considered for direct control including those with inherent or designed storage characteristics. The model uses a dynamic programming technique to determine the optimal operating strategy for a given set of conditions. The use of the model is demonstrated. Case study results indicate that the production cost savings that can be achieved through the use of direct load control are highly dependent on utility characteristics, load characteristics, storage capacity, and penetration. The load characteristics that produce the greatest savings are: large storage capacity; high coincidence with the system peak; large connected load per point; and moderately high diversity fraction.

Kuliasha, M.A.

1980-10-01T23:59:59.000Z

210

Interlayer Structure and Dynamics of Cl-Bearing Hydrotalcite: Far Infrared Spectroscopy and Molecular Dynamics Modeling  

SciTech Connect

Comparison of the observed far-infrared (FIR) spectrum of Cl--containing hydrotalcite, [Mg3Al(OH)8]Cl?3H2O, with its power spectrum calculated using molecular dynamics (MD) computer simulation provides greatly increased understanding of the structure and vibrational dynamics in the interlayers of layered double hydroxides. The simulation model assumes an ordered Mg3Al arrangement in the octahedral layer and no constraints on the movement of any atoms or on the geometry and symmetry of the simulation supercell. Calculated anisotropic components of the individual atomic power spectra in combination with computed animations of the vibrational modes from normal mode analysis allow for reliable interpretations of the observed spectral bands. For the vibrations related to octahedral cation motions, bands near 145, 180 and 250 cm-1 are due dominantly to Mg vibration in the z direction (perpendicular to the hydroxide layers), Al vibration in the z direction and Mg and Al vibrations in the x-y plane (parallel to the hydroxide layers), respectively. The low frequency vibrational motions of the interlayer are controlled by a network of hydrogen bonds formed among interlayer water molecules, Cl- ions, and the OH groups of the main hydroxide layers. The bands near 40-70 cm-1 are related to the translational motions of interlayer Cl- and H2O in the x-y plane, and the bands near 120 cm-1 and 210 cm-1 are due largely to translational motions of the interlayer species in the z direction. The three librational modes of interlayer water molecules near 390, 450 and 540 cm-1 correspond to twisting, rocking and wagging hindered rotations, respectively. The spectral components of the interlayer Cl- motions are remarkably similar to those of bulk aqueous chloride solutions, reflecting the structural and dynamic similarity of the nearest-neighbor Cl- environments in the interlayer and in solution.

Wang, Jianwei; Kalinichev, Andrey G.; Amonette, James E.; Kirkpatrick, Robert J.

2003-02-01T23:59:59.000Z

211

A Unified Technique for Dynamic Modeling and Stability Analysis of Microgrid Systems.  

E-Print Network (OSTI)

??This work presents a unified method for dynamic modeling and stability analysis of microgrid power systems. Using the automated state-model generation algorithm, a state-space model… (more)

Johnson, Brian B.

2010-01-01T23:59:59.000Z

212

Improved representation of tropical Pacific ocean-atmosphere dynamics in an intermediate complexity climate model  

Science Conference Proceedings (OSTI)

A new anomaly coupling technique is introduced into a coarse-resolution dynamic climate model (LOVECLIM), improving the model’s representation of eastern equatorial Pacific surface temperature variability. The anomaly coupling amplifies the ...

Ryan L. Sriver; Axel Timmermann; Michael E. Mann; Klaus Keller; Hugues Goosse

213

Oceanic Rossby Wave Dynamics and the ENSO Period in a Coupled Model  

Science Conference Proceedings (OSTI)

Tropical ocean wave dynamics associated with the El Niño–Southern Oscillation cycle in a coupled model are examined. The ocean–atmosphere model consists of statistical atmosphere coupled to a simple reduced gravity model of the tropical Pacific ...

Ben P. Kirtman

1997-07-01T23:59:59.000Z

214

Transient Climate Change in the CSIRO Coupled Model with Dynamic Sea Ice  

Science Conference Proceedings (OSTI)

The CSIRO coupled model has been used in a “transient” greenhouse experiment. This model contains atmospheric, oceanic, comprehensive sea-ice (dynamic/thermodynamic plus leads), and biospheric submodels. The model control run (over 100 years long)...

Hal B. Gordon; Siobhan P. O’Farrell

1997-05-01T23:59:59.000Z

215

Developing a Modeling Framework for Assessing Population Impacts of  

NLE Websites -- All DOE Office Websites (Extended Search)

Developing a Modeling Framework for Assessing Population Impacts of Developing a Modeling Framework for Assessing Population Impacts of Residential Air Quality Policies Speaker(s): Jennifer Logue Date: November 13, 2012 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Brett Singer People spend the majority of their time in residences and the health burden of indoor air is significant. However, the definitions of "acceptable" and "good" indoor air quality (IAQ), and the most effective, energy efficient methods for achieving various levels of IAQ are still matters of research and debate. Current ventilation standards focus on minimum requirements for overall and mechanically provided ventilation rates, and vented combustion equipment, and require only the installation of kitchen and bath exhaust fans for source control. These standards generally are

216

A Model for the Dynamics of Gene Networks  

E-Print Network (OSTI)

In this work we propose a model for gene expression based on the theory of random dynamical systems (RDS) and show that it has a "modularity property" in the following sense: given any collection of genes that are linked in a transcriptional network, if each of them is individually described by a certain class of RDS then there is a natural, and essentially unique, prescription for coupling them together, respecting the network topology, in such a way that the collective system formed by all genes is a RDS as well. Moreover, the class of RDS used to describe the individual genes is flexible enough to account for a wide range of stochastic behaviors within the realm of stationary processes.

Fernando Antoneli; Renata C. Ferreira; Francisco Bosco; Marcelo R. S. Briones

2013-05-14T23:59:59.000Z

217

Hydro-dynamical models for the chaotic dripping faucet  

E-Print Network (OSTI)

We give a hydrodynamical explanation for the chaotic behaviour of a dripping faucet using the results of the stability analysis of a static pendant drop and a proper orthogonal decomposition (POD) of the complete dynamics. We find that the only relevant modes are the two classical normal forms associated with a Saddle-Node-Andronov bifurcation and a Shilnikov homoclinic bifurcation. This allows us to construct a hierarchy of reduced order models including maps and ordinary differential equations which are able to qualitatively explain prior experiments and numerical simulations of the governing partial differential equations and provide an explanation for the complexity in dripping. We also provide a new mechanical analogue for the dripping faucet and a simple rationale for the transition from dripping to jetting modes in the flow from a faucet.

P. Coullet; L. Mahadevan; C. S. Riera

2004-08-20T23:59:59.000Z

218

Fukushima Radiological Assessment Tool: Benchmarking Radiological Assessment and Dose Models using Fukushima Dataset  

Science Conference Proceedings (OSTI)

The Electric Power Research Institute (EPRI) is developing the Fukushima Radiological Assessment Tool (FRAT), a comprehensive database and software application for accessing, analyzing, and interpreting data related to radiological releases from the Fukushima Daiichi Nuclear Power Plant (NPP). This report documents the development of the FRAT to support the benchmarking of emergency response and dose modeling codes used by nuclear power plants, using radiological data from the Fukushima ...

2013-07-31T23:59:59.000Z

219

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

E-Print Network (OSTI)

A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller. Keywords: absorption; chiller; modelling; transient; water-lithium bromide; falling film hal-00713904

Recanati, Catherine

220

USING BOX-JENKINS MODELS TO FORECAST FISHERY DYNAMICS: IDENTIFICATION, ESTIMATION, AND CHECKING  

E-Print Network (OSTI)

USING BOX-JENKINS MODELS TO FORECAST FISHERY DYNAMICS: IDENTIFICATION, ESTIMATION, AND CHECKING Roy MENDELSSOHN! ABSTRACT Box·Jenkins models are suggested as appropriate models for forecasting fishery dynamics in Hawaii. An actual 12-month forecast is shown to give a reasonable fit to the observed data. Most

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Development of an adaptive fuzzy logic-based inverse dynamic model for laser cladding process  

Science Conference Proceedings (OSTI)

The precision, performance, and robustness of model-based controllers depend, to a large extent, on the accuracy of the inverse dynamic model which is incorporated in the design of the controller. Due to complex nature of the laser cladding process and ... Keywords: Adaptive fuzzy modelling, Fuzzy c-means clustering, Inverse dynamic, Laser cladding

Meysar Zeinali; Amir Khajepour

2010-12-01T23:59:59.000Z

222

Modeling issues associated with production reactor safety assessment  

SciTech Connect

This paper describes several Probabilistic Safety Assessment (PSA) modeling issues that are related to the unique design and operation of the production reactors. The identification of initiating events and determination of a set of success criteria for the production reactors is of concern because of their unique design. The modeling of accident recovery must take into account the unique operation of these reactors. Finally, a more thorough search and evaluation of common-cause events is required to account for combinations of unique design features and operation that might otherwise not be included in the PSA. It is expected that most of these modeling issues also would be encountered when modeling some of the other more unique reactor and nonreactor facilities that are part of the DOE nuclear materials production complex. 9 refs., 2 figs.

Stack, D.W. (Los Alamos National Lab., NM (USA)); Thomas, W.R. (Science and Engineering Associates, Inc., Albuquerque, NM (USA))

1990-01-01T23:59:59.000Z

223

PORFLOW Modeling Supporting The H-Tank Farm Performance Assessment  

Science Conference Proceedings (OSTI)

Numerical simulations of groundwater flow and contaminant transport in the vadose and saturated zones have been conducted using the PORFLOW code in support of an overall Performance Assessment (PA) of the H-Tank Farm. This report provides technical detail on selected aspects of PORFLOW model development and describes the structure of the associated electronic files. The PORFLOW models for the H-Tank Farm PA, Rev. 1 were updated with grout, solubility, and inventory changes. The aquifer model was refined. In addition, a set of flow sensitivity runs were performed to allow flow to be varied in the related probabilistic GoldSim models. The final PORFLOW concentration values are used as input into a GoldSim dose calculator.

Jordan, J. M.; Flach, G. P.; Westbrook, M. L.

2012-08-31T23:59:59.000Z

224

Solar Resource Assessment: Databases, Measurements, Models, and Information Sources (Fact Sheet)  

DOE Green Energy (OSTI)

Fact sheet for Solar Resource Assessment Workshop, Denver CO, Oct 29, 2008: ?Solar Resource Assessment Databases, Measurements, Models, and Information Sources

Not Available

2008-10-01T23:59:59.000Z

225

Literature Review and Assessment of Plant and Animal Transfer Factors Used in Performance Assessment Modeling  

Science Conference Proceedings (OSTI)

A literature review and assessment was conducted by Pacific Northwest National Laboratory (PNNL) to update information on plant and animal radionuclide transfer factors used in performance-assessment modeling. A group of 15 radionuclides was included in this review and assessment. The review is composed of four main sections, not including the Introduction. Section 2.0 provides a review of the critically important issue of physicochemical speciation and geochemistry of the radionuclides in natural soil-water systems as it relates to the bioavailability of the radionuclides. Section 3.0 provides an updated review of the parameters of importance in the uptake of radionuclides by plants, including root uptake via the soil-groundwater system and foliar uptake due to overhead irrigation. Section 3.0 also provides a compilation of concentration ratios (CRs) for soil-to-plant uptake for the 15 selected radionuclides. Section 4.0 provides an updated review on radionuclide uptake data for animal products related to absorption, homeostatic control, approach to equilibration, chemical and physical form, diet, and age. Compiled transfer coefficients are provided for cow’s milk, sheep’s milk, goat’s milk, beef, goat meat, pork, poultry, and eggs. Section 5.0 discusses the use of transfer coefficients in soil, plant, and animal modeling using regulatory models for evaluating radioactive waste disposal or decommissioned sites. Each section makes specific suggestions for future research in its area.

Robertson, David E.; Cataldo, Dominic A.; Napier, Bruce A.; Krupka, Kenneth M.; Sasser, Lyle B.

2003-07-20T23:59:59.000Z

226

Bayesian Inference in Dynamic Disequilibrium Models: An Application to the Polish Credit Market  

E-Print Network (OSTI)

We review Bayesian inference for dynamic latent variable models using the data augmentation principle. We detail the difficulties of simulating dynamic latent variables in a Gibbs sampler. We propose an alternative specification of the dynamic disequilibrium model which leads to a simple simulation procedure and renders Bayesian inference fully operational. Identification issues are discussed. We conduct a specification search using the posterior deviance criterion of Spiegelhalter, Best, Carlin, and van der Linde (2002) for a disequilibrium model of the Polish credit market.

Luc Bauwens; Michel Lubrano

2006-01-01T23:59:59.000Z

227

Uncovering land-use dynamics driven by human decision-making - A combined model approach using cellular automata and system dynamics  

Science Conference Proceedings (OSTI)

This paper introduces an enhancement of a cellular automata (CA) model by integrating system dynamics (SD) to incorporate household dynamics and housing decisions as driving forces of residential development. CA macro-models used to simulate the quantitative ... Keywords: Berlin, Cellular automata, Residential choice, Shrinkage, System dynamics, Urban land use modeling

S. Lauf; D. Haase; P. Hostert; T. Lakes; B. Kleinschmit

2012-01-01T23:59:59.000Z

228

GIS and plume dispersion modeling for population exposure assessment  

E-Print Network (OSTI)

The use of Pollutant Plume Dispersion Models is widespread in the evaluation of point sources of air pollution. These models provide valuable insight into the concentration and dispersion of hazardous materials throughout the atmosphere. Traditional methods of dispersion modeling for the permitting of new sources and the monitoring of existing sources have allowed much room for error in terms of the effect of the pollutants on nearby populations (Hardikar, 1995). The capabilities of GIS technology offer an improved method of conducting air quality modeling for permitting, remediation studies, and environmental monitoring. GIS has the ability to develop and manage a comprehensive database of model output, map layers, and demographic data that can prove extremely valuable in the modeling process. This data can serve to extend the capabilities of air pollution dispersion modeling from mere estimation of concentrations to comprehensive exposure assessment of neighboring populations (Lowry, et al. 1995, Maslia, et al. 1994). A study of the Monticello power plant in northeast Texas was conducted using the SCREEN3 mathematical plume dispersion model, US Census Bureau demographic data, and a GIS to examine the effects of the plant output on the people living in the seven county area surrounding the plant.

Archer, Jeffrey Keith

1998-01-01T23:59:59.000Z

229

Modeling the infrastructure dynamics of China -- Water, agriculture, energy, and greenhouse gases  

Science Conference Proceedings (OSTI)

A comprehensive critical infrastructure analysis of the People`s Republic of China was performed to address questions about China`s ability to meet its long-term grain requirements and energy needs and to estimate greenhouse gas emissions in China likely to result from increased agricultural production and energy use. Four dynamic computer simulation models of China`s infrastructures--water, agriculture, energy and greenhouse gas--were developed to simulate, respectively, the hydrologic budgetary processes, grain production and consumption, energy demand, and greenhouse gas emissions in China through 2025. The four models were integrated into a state-of-the-art comprehensive critical infrastructure model for all of China. This integrated model simulates diverse flows of commodities, such as water and greenhouse gas, between the separate models to capture the overall dynamics of the integrated system. The model was used to generate projections of China`s available water resources and expected water use for 10 river drainage regions representing 100% of China`s mean annual runoff and comprising 37 major river basins. These projections were used to develop estimates of the water surpluses and/or deficits in the three end-use sectors--urban, industrial, and agricultural--through the year 2025. Projections of the all-China demand for the three major grains (corn, wheat, and rice), meat, and other (other grains and fruits and vegetables) were also generated. Each geographic region`s share of the all-China grain demand (allocated on the basis of each region`s share of historic grain production) was calculated in order to assess the land and water resources in each region required to meet that demand. Growth in energy use in six historically significant sectors and growth in greenhouse gas loading were projected for all of China.

Conrad, S.H.; Drennen, T.E.; Engi, D.; Harris, D.L.; Jeppesen, D.M.; Thomas, R.P.

1998-08-01T23:59:59.000Z

230

Data Assimilation with Gaussian Mixture Models using the Dynamically Orthogonal Field Equations. Part II. Applications  

E-Print Network (OSTI)

The properties and capabilities of the GMM-DO filter are assessed and exemplified by applications to two dynamical systems: (1) the Double Well Diffusion and (2) Sudden Expansion flows; both of which admit far-from-Gaussian ...

Sondergaard, Thomas

2012-01-01T23:59:59.000Z

231

Identification and Development of a Model of Railway Track Dynamic Behaviour.  

E-Print Network (OSTI)

??The research presented in this thesis has identified and developed a sophisticated computer model for the analysis of railway track dynamic behaviour to be used… (more)

Steffens, David Martyn

2005-01-01T23:59:59.000Z

232

Spatio-temporal pattern formation in coupled models of plankton dynamics and fish school motion  

Science Conference Proceedings (OSTI)

Keywords: bistability, chaos, plankton dynamics, predator-prey model, reaction-diffusion system, rule-based fish school motion, spiral waves

Horst Malchow; Birgit Radtke; Malaak Kallache; Alexander B. Medvinsky; Dmitry A. Tikhonov; Sergei V. Petrovskii

2000-03-01T23:59:59.000Z

233

Dynamics Modeling and Loads Analysis of an Offshore Floating Wind Turbine  

SciTech Connect

This report describes the development, verification, and application of a comprehensive simulation tool for modeling coupled dynamic responses of offshore floating wind turbines.

Jonkman, J. M.

2007-12-01T23:59:59.000Z

234

Horizontal Momentum Diffusion in GCMs Using the Dynamic Smagorinsky Model  

Science Conference Proceedings (OSTI)

A dynamic version of Smagorinsky’s diffusion scheme is presented that is applicable for large-eddy simulations (LES) of the atmospheric dynamics. The approach is motivated (i) by the incompatibility of conventional hyperdiffusion schemes with the ...

Urs Schaefer-Rolffs; Erich Becker

2013-03-01T23:59:59.000Z

235

Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.  

Science Conference Proceedings (OSTI)

Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

2011-06-01T23:59:59.000Z

236

An integrated multi-model approach for air quality assessment: Development and evaluation of the OSCAR Air Quality Assessment System  

Science Conference Proceedings (OSTI)

This paper reports on the development and evaluation of a new modelling system for studying air quality on local scales. A multi-model approach has been adopted to develop the OSCAR Air Quality Modelling System to conduct assessments at different levels ... Keywords: Air quality, Model evaluation, Modelling system, Nitrogen oxides, OSCAR, Particulate matter

Ranjeet S. Sokhi; Hongjun Mao; Srinivas T. G. Srimath; Shiyuan Fan; Nutthida Kitwiroon; Lakhumal Luhana; Jaakko Kukkonen; Mervi Haakana; Ari Karppinen; K. Dick van den Hout; Paul Boulter; Ian S. McCrae; Steinar Larssen; Karl I. Gjerstad; Roberto San José; John Bartzis; Panagiotis Neofytou; Peter van den Breemer; Steve Neville; Anu Kousa; Blanca M. Cortes; Ingrid Myrtveit

2008-03-01T23:59:59.000Z

237

Electrodiffusive model for astrocytic and neuronal ion concentration dynamics  

E-Print Network (OSTI)

Electrical neural signalling typically takes place at the time-scale of milliseconds, and is typically modeled using the cable equation. This is a good approximation for processes when ionic concentrations vary little during the time course of a simulation. During periods of intense neural signalling, however, the local extracellular K+ concentration may increase by several millimolars. Clearance of excess K+ likely depends partly on diffusion in the extracellular space, partly on local uptake by- and intracellular transport within astrocytes. This process takes place at the time scale of seconds, and can not be modeled accurately without accounting for the spatiotemporal variations in ion concentrations. The work presented here consists of two main parts: First, we developed a general electrodiffusive formalism for modeling ion concentration dynamics in a one-dimensional geometry, including both an intra- and extracellular domain. The formalism was based on the Nernst-Planck equations. It ensures (i) consistency between the membrane potential and ion concentrations, (ii) global particle/charge conservation, and (iii) accounts for diffusion and concentration dependent variations in resistivities. Second, we applied the formalism to model how astrocytes exchange ions with the ECS, and identified the key astrocytic mechanisms involved in K+ removal from high concentration regions. We found that a local increase in extracellular K\\textsuperscript{+} evoked a local depolarization of the astrocyte membrane, which at the same time (i) increased the local astrocytic uptake of K\\textsuperscript{+}, (ii) suppressed extracellular transport of K+, (iii) increased transport of K+ within astrocytes, and (iv) facilitated astrocytic relase of K+ in extracellular low concentration regions. In summary, these mechanisms seem optimal for shielding the extracellular space from excess K+.

Geir Halnes; Ivar Østby; Klas H. Pettersen; Stig W. Omholt; Gaute T. Einevoll

2013-04-29T23:59:59.000Z

238

Integrated dynamic policy management methodology and system for strategic environmental assessment of golf course installation policy in Taiwan  

Science Conference Proceedings (OSTI)

Strategic environmental assessment (SEA) focuses primarily on assessing how policies, plans, and programs (PPPs) influence the sustainability of the involved regions. However, the processes of assessing policies and developing management strategies for pollution load and resource use are usually separate in the current SEA system. This study developed a policy management methodology to overcome the defects generated during the above processes. This work first devised a dynamic management framework using the methods of systems thinking, system dynamics, and Managing for Results (MFRs). Furthermore, a driving force-pressure-state-impact-response (DPSIR) indicator system was developed. The golf course installation policy was applied as a case study. Taiwan, counties of Taiwan, and the golf courses within those individual counties were identified as a system, subsystems, and objects, respectively. This study identified an object-linked double-layer framework with multi-stage-option to simultaneously to quantify golf courses in each subsystem and determine ratios of abatement and allocation for pollution load and resource use of each golf course. The DPSIR indicator values for each item of each golf course in each subsystem are calculated based on the options taken in the two decision layers. The summation of indicator values for all items of all golf courses in all subsystems according to various options is defined as the sustainability value of the policy. An optimization model and a system (IDPMS) were developed to obtain the greatest sustainability value of the policy, while golf course quantity, human activity intensity, total quantities of pollution load and resource use are simultaneously obtained. The solution method based on enumeration of multiple bounds for objectives and constraints (EMBOC) was developed for the problem with 1.95 x 10{sup 128} combinations of possible options to solve the optimal solution in ten minutes using a personal computer with 3.0 GHz CPU. This study obtain the policy with the optimal environmental sustainability value in Taiwan is 102 golf courses. Human activity intensity and total quantities of pollution load and resource use which are concurrently obtained are less than those of the existing policy and the existing quantities in 2006. The optimal solution remains unchanged under most sensitivity analysis conditions, unless the weights and constraints are extremely changed. The analytical results indicate that the proposed methodology can be used to assist the authorities for simultaneously generating and assessing the policy during the SEA process.

Chen, Ching-Ho, E-mail: chchen@tea.ntue.edu.t [Department of Social and Regional Development, National Taipei University of Education, Taipei City 106, Taiwan (China); Liu, Wei-Lin, E-mail: wlliu@nanya.edu.t [Department of Civil and Environmental Engineering, Nanya Institute of Technology, Jungli, Taoyuan 320, Taiwan (China); Graduate Institute of Environmental Engineering, National Central University, Jungli, Taoyuan 320, Taiwan (China); Liaw, Shu-Liang [Graduate Institute of Environmental Engineering, National Central University, Jungli, Taoyuan 320, Taiwan (China)

2011-01-15T23:59:59.000Z

239

The Distributive Impact Assessment Model (DIAM): Technology share component  

DOE Green Energy (OSTI)

The models described in this report are used to allocate total energy consumption in an energy end-use service area by fuel type (including electricity) within the Distributive Impact Assessment Model (DIAM) framework. The primary objective of the DIAM is to provide energy consumption and expenditure forecasts for different population categories that are consistent with the US Department of Energy (DOE) Energy Information Administration`s (EIA`s) National Energy Modeling System (NEMS) forecast, which is produced annually in the Annual Energy Outlook and periodically in support of DOE policy formulation and analysis. The models are multinominal logit models that have been estimated using EIA`s 1990 Residential Energy Consumption Survey. Three models were estimated: space heating share, water heating share, and cooking share. These models are used to allocate total end-use service consumption over different technologies defined by fuel type characteristics. For each of the end-use service categories, consumption shares are estimated for a subset of six fuel types: natural gas, electricity, liquid petroleum gas, fuel oil/kerosene, wood, and other fuel.

Poyer, D.A.; Earl, E.; Bonner, B.

1995-03-01T23:59:59.000Z

240

CliCrop: a Crop Water-Stress and Irrigation Demand Model for an Integrated Global Assessment Model Approach  

E-Print Network (OSTI)

This paper describes the use of the CliCrop model in the context of climate change general assessment

Fant, C.A.

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241

Modeling toxic endpoints for improving human health risk assessment  

E-Print Network (OSTI)

Risk assessment procedures for mixtures of polycyclic aromatic hydrocarbons (PAHs) present a problem due to the lack of available potency and toxicity data on mixtures and individual compounds. This study examines the toxicity of parent compound PAHs and binary mixtures of PAHs in order to bridge the gap between component assessment and mixture assessment. Seven pure parent compound PAHs and four binary mixtures of PAHs were examined in the Salmonella/Microsome Mutagenicity Assay, a Gap Junction Intercellular Communication (GJIC) assay and the 7-ethoxyresorufin-O-deethylase assay (EROD). These assays were chosen for their ability to measure specific toxic endpoints related to the carcinogenic process (i.e. initiation, promotion, progression). Data from these assays was used in further studies to build Quantitative Structure-Activity Relationships (QSARs) to estimate toxic endpoints and to test the additive assumption in PAH mixtures. These QSAR models will allow for the development of bioassay based potential potencies (PPB) or toxic equivalency factors (TEFs) that are derived not only from bioassay data, but also from structure, activity, and physical/chemical properties. These models can be extended to any environmental media to evaluate risk to human health from exposures to PAHs.

Bruce, Erica Dawn

2007-05-01T23:59:59.000Z

242

USING COPULAS TO MODEL DEPENDENCE IN SIMULATION RISK ASSESSMENT  

SciTech Connect

Typical engineering systems in applications with high failure consequences such as nuclear reactor plants often employ redundancy and diversity of equipment in an effort to lower the probability of failure and therefore risk. However, it has long been recognized that dependencies exist in these redundant and diverse systems. Some dependencies, such as common sources of electrical power, are typically captured in the logic structure of the risk model. Others, usually referred to as intercomponent dependencies, are treated implicitly by introducing one or more statistical parameters into the model. Such common-cause failure models have limitations in a simulation environment. In addition, substantial subjectivity is associated with parameter estimation for these models. This paper describes an approach in which system performance is simulated by drawing samples from the joint distributions of dependent variables. The approach relies on the notion of a copula distribution, a notion which has been employed by the actuarial community for ten years or more, but which has seen only limited application in technological risk assessment. The paper also illustrates how equipment failure data can be used in a Bayesian framework to estimate the parameter values in the copula model. This approach avoids much of the subjectivity required to estimate parameters in traditional common-cause failure models. Simulation examples are presented for failures in time. The open-source software package R is used to perform the simulations. The open-source software package WinBUGS is used to perform the Bayesian inference via Markov chain Monte Carlo sampling.

Dana L. Kelly

2007-11-01T23:59:59.000Z

243

A Double Fourier Series (DFS) Dynamical Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong as an alternative dynamical option in a model system that was ported into the Global/Regional Integrated Model System (GRIMs). A message ...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

2013-09-01T23:59:59.000Z

244

A Coupled Dynamical Ocean–Energy Balance Atmosphere Model for Paleoclimate Studies  

Science Conference Proceedings (OSTI)

The Bern3D coupled three-dimensional dynamical ocean–energy balance atmosphere model is introduced and the atmospheric component is discussed in detail. The model is of reduced complexity, developed to perform extensive sensitivity studies and ...

Stefan P. Ritz; Thomas F. Stocker; Fortunat Joos

2011-01-01T23:59:59.000Z

245

Dynamic Surface Interface Exchanges of Mercury: A Review and Compartmentalized Modeling Framework  

Science Conference Proceedings (OSTI)

This paper presents a review of recent natural surface mercury exchange research in the context of a new modeling framework. The literature indicates that the mercury biogeochemical flux is more dynamic than the current models predict, with ...

Jesse O. Bash; Patricia Bresnahan; David R. Miller

2007-10-01T23:59:59.000Z

246

Evolutionary Approaches for Strain Optimization Using Dynamic Models under a Metabolic Engineering Perspective  

Science Conference Proceedings (OSTI)

One of the purposes of Systems Biology is the quantitative modeling of biochemical networks. In this effort, the use of dynamical mathematical models provides for powerful tools in the prediction of the phenotypical behavior of microorganisms under distinct ...

Pedro Evangelista; Isabel Rocha; Eugénio C. Ferreira; Miguel Rocha

2009-04-01T23:59:59.000Z

247

Dynamic modeling of planar parallel robots considering passive joint sensor data  

Science Conference Proceedings (OSTI)

Model-based advanced control approaches are needed to achieve high speed and acceleration and precision in robotic operations. These control schemes need a proper dynamic model. Many approaches have been proposed by different authors in order to obtain ...

Asier Zubizarreta; Itziar Cabanes; Marga Marcos; Charles Pinto

2010-09-01T23:59:59.000Z

248

Boundary Layer Dynamics in a Simple Model for Convectively Coupled Gravity Waves  

Science Conference Proceedings (OSTI)

A simplified model of intermediate complexity for convectively coupled gravity waves that incorporates the bulk dynamics of the atmospheric boundary layer is developed and analyzed. The model comprises equations for velocity, potential ...

Michael L. Waite; Boualem Khouider

2009-09-01T23:59:59.000Z

249

A Double Fourier Series (DFS) Dynamic Core in a Global Atmospheric Model with Full Physics  

Science Conference Proceedings (OSTI)

This study describes an application of the double Fourier series (DFS) spectral method developed by Cheong (2006) as an alternative dynamic option in a model system that was ported in the Global/Regional Integrated Model system (GRIMs). A message-...

Hoon Park; Song-You Hong; Hyeong-Bin Cheong; Myung-Seo Koo

250

Networking technology adoption : system dynamics modeling of fiber-to-the-home  

E-Print Network (OSTI)

A system dynamics model is developed and run to study the adoption of fiber-to-the-home as a residential broadband technology. Communities that currently do not have broadband in the United States are modeled. This case ...

Kelic, Andjelka, 1972-

2005-01-01T23:59:59.000Z

251

Dynamics and Thermodynamics of a Warming Event in a Coupled Tropical Atmosphere–Ocean Model  

Science Conference Proceedings (OSTI)

A simple coupled ocean–atmosphere model, similar to that of Zebiak and Cane, is used to examine the dynamic and thermodynamic processes associated with El Niño/Southern Oscillation (ENSO). The model is run for 300 years. The interannual ...

David S. Battisti

1988-10-01T23:59:59.000Z

252

Ensemble Simulations with Coupled Atmospheric Dynamic and Dispersion Models: Illustrating Uncertainties in Dosage Simulations  

Science Conference Proceedings (OSTI)

Ensemble simulations made using a coupled atmospheric dynamic model and a probabilistic Lagrangian puff dispersion model were employed in a forensic analysis of the transport and dispersion of a toxic gas that may have been released near Al ...

Thomas T. Warner; Rong-Shyang Sheu; James F. Bowers; R. Ian Sykes; Gregory C. Dodd; Douglas S. Henn

2002-05-01T23:59:59.000Z

253

Designing of integrated system-dynamics models for an oil company  

Science Conference Proceedings (OSTI)

This paper presents a new approach to designing integrated simulation models for large corporations. This approach is based on the use of system-dynamics methods for implementing models of segments of the vertically integrated company taking into account ...

Andranik S. Akopov

2012-12-01T23:59:59.000Z

254

Modeling the Atmospheric General Circulation Using a Spherical Geodesic Grid: A New Class of Dynamical Cores  

Science Conference Proceedings (OSTI)

This paper documents the development and testing of a new type of atmospheric dynamical core. The model solves the vorticity and divergence equations in place of the momentum equation. The model is discretized in the horizontal using a geodesic ...

Todd D. Ringler; Ross P. Heikes; David A. Randall

2000-07-01T23:59:59.000Z

255

Dynamical Core of an Atmospheric General Circulation Model on a Yin–Yang Grid  

Science Conference Proceedings (OSTI)

The three-dimensional dynamical core of an atmospheric general circulation model employing Yin–Yang grid is developed and examined. Benchmark test cases based on the shallow-water model configuration are first performed to examine the validity of ...

Yuya Baba; Keiko Takahashi; Takeshi Sugimura; Koji Goto

2010-10-01T23:59:59.000Z

256

Toward Dynamic, Longitudinal, Agent-Based Microsimulation Models of Human Activity in Urban Settings  

E-Print Network (OSTI)

for theory. FOCUSING ON INTERACTION USING AGENT-BASED MODELSBackground Agent-based models are characterized by theirEnvironment The dynamic agent-based model seeks to produce,

Rindt, Craig R.; Marca, James E.; McNally, Michael G.

2002-01-01T23:59:59.000Z

257

African Easterly Wave Dynamics in a Mesoscale Numerical Model: The Upscale Role of Convection  

Science Conference Proceedings (OSTI)

To examine the dynamical role of convection in African easterly wave (AEW) life cycles the Weather Research and Forecasting (WRF) model is used to simulate the evolution of a single AEW from September 2004. The model simulations are validated ...

Gareth J. Berry; Chris D. Thorncroft

2012-04-01T23:59:59.000Z

258

Optimal foreign borrowing in a multisector dynamic equilibrium model for Brazil  

E-Print Network (OSTI)

This paper shows how a dynamic multisector equilibrium model can be formulated to be able to analyze the optimal borrowing policy of a developing country. It also describes how a non-linear programming model with the ...

Tourinho, Octv?io A. F.

1985-01-01T23:59:59.000Z

259

Determination of Forecast Errors Arising from Different Components of Model Physics and Dynamics  

Science Conference Proceedings (OSTI)

This paper addresses a procedure to extract error estimates for the physical and dynamical components of a forecast model. This is a two-step process in which contributions to the forecast tendencies from individual terms of the model equations ...

T. N. Krishnamurti; J. Sanjay; A. K. Mitra; T. S. V. Vijaya Kumar

2004-11-01T23:59:59.000Z

260

MATHEMATICAL MODELS OF HYSTERESIS (DYNAMIC PROBLEMS IN HYSTERESIS)  

SciTech Connect

This research has further advanced the current state of the art in the areas of dynamic aspects of hysteresis and nonlinear large scale magnetization dynamics. The results of this research will find important engineering applications in the areas of magnetic data storage technology and the emerging technology of “spintronics”. Our research efforts have been focused on the following tasks: • Study of fast (pulse) precessional switching of magnetization in magnetic materials. • Analysis of critical fields and critical angles for precessional switching of magnetization. • Development of inverse problem approach to the design of magnetic field pulses for precessional switching of magnetization. • Study of magnetization dynamics induced by spin polarized current injection. • Construction of complete stability diagrams for spin polarized current induced magnetization dynamics. • Development of the averaging technique for the analysis of the slow time scale magnetization dynamics. • Study of thermal effects on magnetization dynamics by using the theory of stochastic processes on graphs.

Professor Isaak Mayergoyz

2006-08-21T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
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261

An Assessment of Models which use Satellite Data to Estimate Solar Irradiance at the Earth's Surface  

Science Conference Proceedings (OSTI)

The performances of three models which use satellite data to estimate solar irradiance at the Earth's surface are assessed using measured radiation data from a midlatitude location. Assessment of the models is made possible through the accurate ...

Clifford Raphael; John E. Hay

1984-05-01T23:59:59.000Z

262

Seasonal and Long-Term Atmospheric Responses to Reemerging North Pacific Ocean Variability: A Combined Dynamical and Statistical Assessment  

Science Conference Proceedings (OSTI)

The atmospheric response to a North Pacific subsurface oceanic temperature anomaly is studied in a coupled ocean–atmosphere general circulation model using a combined dynamical and statistical approach, with the focus on the evolution at seasonal ...

Zhengyu Liu; Yun Liu; Lixin Wu; R. Jacob

2007-03-01T23:59:59.000Z

263

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers  

E-Print Network (OSTI)

A simple model of impact dynamics in many dimensional systems, with applications to heat exchangers present a simple hybrid model of impact dynamics in heat exchangers. The method, based on graph theory and experimental evidence. 1 Introduction A heat exchanger typically consists of a large number of thin pipes

Bristol, University of

264

Modeling considerations in static and dynamic voltage stability studies of shipboard power systems  

Science Conference Proceedings (OSTI)

Better modeling is a key issue to system analysis and emulating real system performances accurately. This paper addresses modeling considerations and approaches to be taken for voltage stability analysis. Two approaches, static and dynamic analysis, ... Keywords: PSCAD, dynamic analysis, numerical integration method, static analysis, voltage stability

Minglan Lin; Anurag K. Srivastava; Noel N. Schulz

2007-07-01T23:59:59.000Z

265

Linear driving force models for dynamic adsorption of volatile organic compound traces by porous adsorbent beds  

Science Conference Proceedings (OSTI)

Models for the dynamic adsorption of volatile organic compound (VOC) traces in air are considered. They are based on the linear driving force approximation associated with various adsorption isotherms characteristic of the couple VOC-adsorbent (Langmuir, ... Keywords: Comsol, Dubinin-Astakhov isotherm, Dynamic adsorption modelling, Finite element

Agnès Joly; Alain Perrard

2009-08-01T23:59:59.000Z

266

Steady-state power flow modeling for a dynamic voltage restorer  

Science Conference Proceedings (OSTI)

This paper presents analysis, modeling and simulation of power distribution network performance incorporating with an installed dynamic voltage restorer (DVR). DVR is one of series compensators used in power distribution systems in order to maintain ... Keywords: Gauss-Seidel method, dynamic voltage restorer, modeling, power flow, simulation

T. Ratniyomchai; T. Kulworawanichpong

2006-03-01T23:59:59.000Z

267

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including Ionization Processes  

E-Print Network (OSTI)

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes

Zhigilei, Leonid V.

268

The implementation of polarizable and flexible models in molecular dynamics simulations  

Science Conference Proceedings (OSTI)

We discuss a new methodology for implementing polarizable and flexible molecular models - the fluctuating charge and intramolecular potential (fCINTRA) method - in Molecular Dynamics (MD) simulations. An example has been provided for ethanol. In these ... Keywords: message passing interface, molecular dynamics simulation, polarizable and flexible model

Shihao Wang; Natalie M. Cann

2009-06-01T23:59:59.000Z

269

From empirical data to mathematical model: using population dynamics to characterize insurgencies  

Science Conference Proceedings (OSTI)

Understanding the nature of insurgencies is critical to determining strategies for mitigating their effects. Modeling insurgencies is one method to provide a structured methodology to gain insight into the various characteristics of insurgencies. This ... Keywords: homeland security, insurgency modeling, population dynamics, system dynamics

John A. Sokolowski; Catherine M. Banks

2007-07-01T23:59:59.000Z

270

Assessing Tracer Transport Algorithms and the Impact of Vertical Resolution in a Finite-Volume Dynamical Core  

Science Conference Proceedings (OSTI)

Modeling the transport of trace gases is an essential part of any atmospheric model. The tracer transport scheme in the Community Atmosphere Model finite-volume dynamical core (CAM-FV), which is part of the National Center for Atmospheric Research’...

James Kent; Christiane Jablonowski; Jared P. Whitehead; Richard B. Rood

2012-05-01T23:59:59.000Z

271

Data-driven dynamic emulation modelling for the optimal management of environmental systems  

Science Conference Proceedings (OSTI)

The optimal management of large environmental systems is often limited by the high computational burden associated to the process-based models commonly adopted to describe such systems. In this paper we propose a novel data-driven Dynamic Emulation Modelling ... Keywords: Data-driven models, Emulation modelling, Process-based models, Variable selection, Water resources planning and management

A. Castelletti; S. Galelli; M. Restelli; R. Soncini-Sessa

2012-06-01T23:59:59.000Z

272

Application of dynamic programming model in inventory management.  

E-Print Network (OSTI)

???This thesis aims to apply dynamic programming approach to formulate three main topics related to inventory management under three real world situations and then propose… (more)

Tao, Feng ( ??)

2011-01-01T23:59:59.000Z

273

Modeling System Development for the Evaluation of Dynamic Air...  

NLE Websites -- All DOE Office Websites (Extended Search)

supply and demand. The challenges of dynamic analysis of emissions impacts from the energy sector have substantially increased with a new focus on the emerging distributed...

274

Integrated dynamic landscape analysis and modeling system (IDLAMS) : installation manual.  

SciTech Connect

The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) is a prototype, integrated land management technology developed through a joint effort between Argonne National Laboratory (ANL) and the US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL). Dr. Ronald C. Sundell, Ms. Pamela J. Sydelko, and Ms. Kimberly A. Majerus were the principal investigators (PIs) for this project. Dr. Zhian Li was the primary software developer. Dr. Jeffrey M. Keisler, Mr. Christopher M. Klaus, and Mr. Michael C. Vogt developed the decision analysis component of this project. It was developed with funding support from the Strategic Environmental Research and Development Program (SERDP), a land/environmental stewardship research program with participation from the US Department of Defense (DoD), the US Department of Energy (DOE), and the US Environmental Protection Agency (EPA). IDLAMS predicts land conditions (e.g., vegetation, wildlife habitats, and erosion status) by simulating changes in military land ecosystems for given training intensities and land management practices. It can be used by military land managers to help predict the future ecological condition for a given land use based on land management scenarios of various levels of training intensity. It also can be used as a tool to help land managers compare different land management practices and further determine a set of land management activities and prescriptions that best suit the needs of a specific military installation.

Li, Z.; Majerus, K. A.; Sundell, R. C.; Sydelko, P. J.; Vogt, M. C.

1999-02-24T23:59:59.000Z

275

Integrated dynamic landscape analysis and modeling system (IDLAMS) : programmer's manual.  

SciTech Connect

The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) is a prototype, integrated land management technology developed through a joint effort between Argonne National Laboratory (ANL) and the US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL). Dr. Ronald C. Sundell, Ms. Pamela J. Sydelko, and Ms. Kimberly A. Majerus were the principal investigators (PIs) for this project. Dr. Zhian Li was the primary software developer. Dr. Jeffrey M. Keisler, Mr. Christopher M. Klaus, and Mr. Michael C. Vogt developed the decision analysis component of this project. It was developed with funding support from the Strategic Environmental Research and Development Program (SERDP), a land/environmental stewardship research program with participation from the US Department of Defense (DoD), the US Department of Energy (DOE), and the US Environmental Protection Agency (EPA). IDLAMS predicts land conditions (e.g., vegetation, wildlife habitats, and erosion status) by simulating changes in military land ecosystems for given training intensities and land management practices. It can be used by military land managers to help predict the future ecological condition for a given land use based on land management scenarios of various levels of training intensity. It also can be used as a tool to help land managers compare different land management practices and further determine a set of land management activities and prescriptions that best suit the needs of a specific military installation.

Klaus, C. M.; Li, Z.; Majerus, K. A.; Sundell, R. C.; Sydelko, P. J.; Vogt, M. C.

1999-02-24T23:59:59.000Z

276

Modeling dynamic substitution processes in energy supply systems  

SciTech Connect

Dynamic substitution processes between energy-conversion techniques are very important phenomena for the restructuring of energy systems. Using the method of synergetics, the authors develop a probabilistic model framework for individual decisions and their effects on the macroscopic configuration of energy supply systems. The derived probability transition rates are associated with socioeconomic parameters that are the basis for individual decisions. The authors state preliminary results of a case study for the room heating of private households in the former West Germany, which are based on a small data sample and a nonrepresentative poll. They find that the number of heating systems of one type, which are already installed, their ease of use, and the cost are the most important parameters for the selection of a new heating system. Using the estimated parameters, they simulate the diffusion of a new type of heating system, which is regarded as better than all the others, into the energy supply system. Its market share will reach 11--18% after 35 years.

Christian, M.; Groscurth, H.M.

1995-05-01T23:59:59.000Z

277

Spatially embedded social networks: dynamic models and data reconstruction  

E-Print Network (OSTI)

Agent-Based Models . . . . . . . . . . .Aspects of Modeling Agent-Based Models . . . . . . . .and Hans J. Herrmann. “Agent-based model for friendship in

Hegemann, Rachel Anne

2012-01-01T23:59:59.000Z

278

An Inspector's Assessment of the New Model Safeguards Approach for Enrichment Plants  

SciTech Connect

This conference paper assesses the changes that are being made to the Model Safeguards Approach for Gas Centrifuge Enrichment Plants.

Curtis, Michael M.

2007-07-31T23:59:59.000Z

279

HVAC Modeling for Cost of Ownership Assessment in Biotechnology & Drugs Manufacturing  

E-Print Network (OSTI)

2000 Broomes, Peter. , “HVAC Modeling for Cost of Ownership2000 Broomes, Peter. , “HVAC Results Comparison”, April,HVAC Modeling for Cost of Ownership Assessment in

Broomes, Peter; Dornfeld, David A

2003-01-01T23:59:59.000Z

280

Towards Assessing NARCCAP Regional Climate Model Credibility for the North American Monsoon: Current Climate Simulations  

Science Conference Proceedings (OSTI)

We examine 17 dynamically downscaled simulations produced as part of the North American Regional Climate Change Assessment Program (NARCCAP) for their skill in reproducing the North American Monsoon system. We focus on precipitation and the ...

Melissa S. Bukovsky; David J. Gochis; Linda O. Mearns

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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281

A Further Assessment of Treatment Effects in the Florida Area Cumulus Experiment through Guided Linear Modeling  

Science Conference Proceedings (OSTI)

The Florida Area Cumulus Experiment (FACE) was a two-stage program dedicated to assessing the potential of “dynamic seeding” for enhancing convective rainfall in a fixed target area. FACE-1 (1970–76) was an exploratory cloud seeding experiment ...

J. A. Flueck; W. L. Woodley; A. G. Barnston; T. J. Brown

1986-04-01T23:59:59.000Z

282

ASSESSING THE MINIMUM INSTRUMENTATION TO WELL TUNE EXISTING MEDIUM SIZED OFFICE BUILDING ENERGY MODELS.  

E-Print Network (OSTI)

??Dynamic whole building energy models (BEMs) are created for various reasons: to evaluate alternative design strategies; compliance checks with energy codes; apply certifications at the… (more)

Xu, Ke

2012-01-01T23:59:59.000Z

283

Coupled thermodynamic-dynamic semi-analytical model of Free Piston Stirling engines  

E-Print Network (OSTI)

The study of free piston Stirling engine (FPSE) requires both accurate thermodynamic and dynamic modelling to predict its performances. The steady state behaviour of the engine partly relies on non linear dissipative phenomena such as pressure drop loss within heat exchangers which is dependant on the temperature within the associated components. An analytical thermodynamic model which encompasses the effectiveness and the flaws of the heat exchangers and the regenerator has been previously developed and validated. A semi-analytical dynamic model of FPSE is developed and presented in this paper. The thermodynamic model is used to define the thermal variables that are used in the dynamic model which evaluates the kinematic results. Thus, a coupled iterative strategy has been used to perform a global simulation. The global modelling approach has been validated using the experimental data available from the NASA RE-1000 Stirling engine prototype. The resulting coupled thermodynamic-dynamic model using a standard...

Formosa, Fabien

2013-01-01T23:59:59.000Z

284

THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL  

SciTech Connect

The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. The Pena Blanca Natural Analogue Performance Assessment Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash-flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following analogous characteristics as compared to the Yucca Mountain repository site: (1) Analogous source--UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geology--(i.e. fractured, welded, and altered rhyolitic ash-flow tuffs); (3) Analogous climate--Semiarid to arid; (4) Analogous setting--Volcanic tuffs overlie carbonate rocks; and (5) Analogous geochemistry--Oxidizing conditions Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table.

G. Saulnier and W. Statham

2006-04-16T23:59:59.000Z

285

Spatially Informed Plant PRA Models for Security Assessment  

SciTech Connect

Traditional risk models can be adapted to evaluate plant response for situations where plant systems and structures are intentionally damaged, such as from sabotage or terrorism. This paper describes a process by which traditional risk models can be spatially informed to analyze the effects of compound and widespread harsh environments through the use of 'damage footprints'. A 'damage footprint' is a spatial map of regions of the plant (zones) where equipment could be physically destroyed or disabled as a direct consequence of an intentional act. The use of 'damage footprints' requires that the basic events from the traditional probabilistic risk assessment (PRA) be spatially transformed so that the failure of individual components can be linked to the destruction of or damage to specific spatial zones within the plant. Given the nature of intentional acts, extensive modifications must be made to the risk models to account for the special nature of the 'initiating events' associated with deliberate adversary actions. Intentional acts might produce harsh environments that in turn could subject components and structures to one or more insults, such as structural, fire, flood, and/or vibration and shock damage. Furthermore, the potential for widespread damage from some of these insults requires an approach that addresses the impacts of these potentially severe insults even when they occur in locations distant from the actual physical location of a component or structure modeled in the traditional PRA. (authors)

Wheeler, Timothy A. [Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185 (United States); Thomas, Willard [Omicron Safety and Risk Technologies, Inc., 2500 Louisiana Boulevard, Suite 410. Albuquerque, NM 87110 (United States); Thornsbury, Eric [U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2006-07-01T23:59:59.000Z

286

The Los Alamos dynamic radiation environment assimilation model (DREAM) for space weather specification and forecasting  

SciTech Connect

The Dynamic Radiation Environment Assimilation Model (DREAM) was developed at Los Alamos National Laboratory to assess, quantify, and predict the hazards from the natural space environment and the anthropogenic environment produced by high altitude nuclear explosions (HANE). DREAM was initially developed as a basic research activity to understand and predict the dynamics of the Earth's Van Allen radiation belts. It uses Kalman filter techniques to assimilate data from space environment instruments with a physics-based model of the radiation belts. DREAM can assimilate data from a variety of types of instruments and data with various levels of resolution and fidelity by assigning appropriate uncertainties to the observations. Data from any spacecraft orbit can be assimilated but DREAM was designed to function with as few as two spacecraft inputs: one from geosynchronous orbit and one from GPS orbit. With those inputs, DREAM can be used to predict the environment at any satellite in any orbit whether space environment data are available in those orbits or not. Even with very limited data input and relatively simple physics models, DREAM specifies the space environment in the radiation belts to a high level of accuracy. DREAM has been extensively tested and evaluated as we transition from research to operations. We report here on one set of test results in which we predict the environment in a highly-elliptical polar orbit. We also discuss long-duration reanalysis for spacecraft design, using DREAM for real-time operations, and prospects for 1-week forecasts of the radiation belt environment.

Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

287

A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei  

Open Energy Info (EERE)

Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Details Activities (0) Areas (0) Regions (0) Abstract: We present here a consistent model, which explains the mechanisms of unrest phenomena at Campi Flegrei (Italy), both at short-term (years) and at secular scales. The model consists basically of two effects: the first one is related to the elastic response of the shallow crust to increasing pressure within a shallow magma chamber; the second involves the fluid-dynamics of shallow aquifers in response to increasing pressure and/or temperature at depth. The most important roles in the proposed model

288

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

SciTech Connect

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.

JACKSON VL

2011-08-31T23:59:59.000Z

289

Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models  

E-Print Network (OSTI)

1 Abstract--Eventually, prediction of transformer thermal performance for dynamic loading will be made using models distilled from measure data, rather than models derived from transformer heat for measuring the acceptability of transformer thermal models. For a model to be acceptable, it must have

290

Predicting essential components of signal transduction networks: a dynamic model of guard cell abscisic acid signaling  

E-Print Network (OSTI)

Plants both lose water and take in carbon dioxide through microscopic stomatal pores, each of which is regulated by a surrounding pair of guard cells. During drought, the plant hormone abscisic acid (ABA) inhibits stomatal opening and promotes stomatal closure, thereby promoting water conservation. Here we synthesize experimental results into a consistent guard cell signal transduction network for ABA-induced stomatal closure, and develop a dynamic model of this process. Our model captures the regulation of more than forty identified network components, and accords well with previous experimental results at both the pathway and whole cell physiological level. Our analysis reveals the novel predictions that the disruption of membrane depolarizability, anion efflux, actin cytoskeleton reorganization, cytosolic pH increase, the phosphatidic acid pathway or of K+ efflux through slowly activating K+ channels at the plasma membrane lead to the strongest reduction in ABA responsiveness. Initial experimental analysis assessing ABA-induced stomatal closure in the presence of cytosolic pH clamp imposed by the weak acid butyrate is consistent with model prediction. Our method can be readily applied to other biological signaling networks to identify key regulatory components in systems where quantitative information is limited.

Song Li; Sarah M. Assmann; Reka Albert

2006-10-05T23:59:59.000Z

291

Can Dynamic Contact Angle Be Measured Using Molecular Modeling?  

E-Print Network (OSTI)

A method is presented for determining the dynamic contact angle at the three-phase contact between a solid, a liquid, and a vapor under an applied force, using molecular simulation. The method is demonstrated using a ...

Malani, Ateeque A. A. G.

292

Empirical Dynamical System Modeling of ENSO Using Nonlinear Inverse Techniques  

Science Conference Proceedings (OSTI)

A statistical technique is presented that allows for the empirical derivation of dynamical system equations from data. It is based on multiple nonparametric regression analysis and is applicable to a broad class of physical systems. It is applied ...

A. Timmermann; H. U. Voss; R. Pasmanter

2001-06-01T23:59:59.000Z

293

Modeling the dynamics and depositional patterns of sandy rivers  

E-Print Network (OSTI)

This thesis seeks to advance our understanding of the dynamic nature, spatial organization and depositional record of topography in sand-bedded rivers. I examine patterns and processes over a wide range of scales, on Earth ...

Jerolmack, Douglas J

2006-01-01T23:59:59.000Z

294

Dynamic reduced order modeling of entrained flow gasifiers  

E-Print Network (OSTI)

Gasification-based energy systems coupled with carbon dioxide capture and storage technologies have the potential to reduce greenhouse gas emissions from continued use of abundant and secure fossil fuels. Dynamic reduced ...

Monaghan, Rory F. D. (Rory Francis Desmond)

2010-01-01T23:59:59.000Z

295

A Bootstrap Method for Software Reliability Assessment Based on a Discretized NHPP Model  

Science Conference Proceedings (OSTI)

We discuss a bootstrap method for software reliability assessment based on a discretized no homogeneous Poisson process (NHPP) model. Ordinarily, model parameters of the discretized NHPP model are estimated by using the regression analysis based on the ... Keywords: Software reliability assessment, Discretized NHPP model, Regression analysis, Bootstrap method

Shinji Inoue; Shigeru Yamada

2012-11-01T23:59:59.000Z

296

Development and illustrative outputs of the Community Integrated Assessment System (CIAS), a multi-institutional modular integrated assessment approach for modelling climate change  

Science Conference Proceedings (OSTI)

This paper describes the development and first results of the ''Community Integrated Assessment System'' (CIAS), a unique multi-institutional modular and flexible integrated assessment system for modelling climate change. Key to this development is the ... Keywords: Bespoke Framework Generator, Carbon tax, Climate change, Community Integrated Assessment System, Coupled modelling, Integrated assessment model, SoftIAM, Software engineering

R. Warren; S. de la Nava Santos; N. W. Arnell; M. Bane; T. Barker; C. Barton; R. Ford; H. -M. Füssel; Robin K. S. Hankin; Rupert Klein; C. Linstead; J. Kohler; T. D. Mitchell; T. J. Osborn; H. Pan; S. C. B. Raper; G. Riley; H. J. Schellnhüber; S. Winne; D. Anderson

2008-05-01T23:59:59.000Z

297

Nonlinear Modeling of the Dynamic Effects of Infused Insulin on Glucose: Comparison of Compartmental With Volterra Models  

E-Print Network (OSTI)

This paper presents the results of a computational study that compares simulated compartmental (differential equation) and Volterra models of the dynamic effects of insulin on blood glucose concentration in humans. In the ...

Markakis, Michail

298

Molecular Models to Emulate Confinement Effects on the Internal Dynamics of Organophosphorous Hydrolase  

SciTech Connect

The confinement of the metalloenzyme organophosphorous hydrolase in functionalized mesoporous silica (FMS) enhances the stability and increases catalytic specific activity by 200% compared to the enzyme in solution. The mechanism by which these processes take place is not well understood. We have developed two coarse-grain models of confinement to provide insights into how the nanocage environment steers enzyme conformational dynamics towards enhanced stability and enzymatic activity. The structural dynamics of organophosphorous hydrolase under the two confinement models are very distinct from each other. Comparisons of the present simulations show that only one model leads to an accurate depiction of the internal dynamics of the enzyme.

Gomes, Diego Enry B.; Lins, Roberto D.; Pascutti, Pedro G.; Straatsma, TP; Soares, Thereza A.

2008-09-28T23:59:59.000Z

299

Dynamic modelling of a double-pendulum gantry crane system incorporating payload  

Science Conference Proceedings (OSTI)

The natural sway of crane payloads is detrimental to safe and efficient operation. Under certain conditions, the problem is complicated when the payloads create a double pendulum effect. This paper presents dynamic modelling of a double-pendulum gantry crane system based on closed-form equations of motion. The Lagrangian method is used to derive the dynamic model of the system. A dynamic model of the system incorporating payload is developed and the effects of payload on the response of the system are discussed. Extensive results that validate the theoretical derivation are presented in the time and frequency domains.

Ismail, R. M. T. Raja; Ahmad, M. A.; Ramli, M. S.; Ishak, R.; Zawawi, M. A. [Faculty of Electrical and Electronics Engineering, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300, Kuantan, Pahang (Malaysia)

2011-06-20T23:59:59.000Z

300

A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano,  

Open Energy Info (EERE)

For The Dynamics Of Pyroclastic Flows At Galeras Volcano, For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras Volcano, Colombia Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents a two-dimensional model for dilute pyroclastic flow dynamics that uses the compressible Navier-Stokes equation coupled with the Diffusion-Convection equation to take into account sedimentation. The model is applied to one of the slopes of Galeras Volcano to show: (1) the temperature evolution with the time; (2) dynamic pressure change; and (3) particle concentration along the computer domain from the eruption to the impact with a topographic barrier located more than 16 km

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Watershed modeling using large-scale distributed computing in Condor and the Soil and Water Assessment Tool model  

Science Conference Proceedings (OSTI)

Models are increasingly being used to quantify the effects of best management practices (BMPs) on water quality. While these models offer the ability to study multiple BMP scenarios, and to analyze impacts of various management decisions on watershed ... Keywords: Condor, Conservation Effectiveness Assessment Program, Lincoln Lake, Soil and Water Assessment Tool Model, TeraGrid, best management practices

Margaret W Gitau; Li-Chi Chiang; Mohamed Sayeed; Indrajeet Chaubey

2012-03-01T23:59:59.000Z

302

STRUCTURAL VALIDATION OF SYSTEM DYNAMICS AND AGENT-BASED SIMULATION MODELS  

E-Print Network (OSTI)

, population dynamics, energy systems, and urban planning. The usefulness of these models is predicated be opened in the bank; efficiency of the oil refinery can be enhanced under the recommended actions including global warming, population dynamics, energy systems, and urban planning simply defy a face

Tesfatsion, Leigh

303

Review: Application of computational fluid dynamics for modeling and designing photobioreactors for microalgae production: A review  

Science Conference Proceedings (OSTI)

The past decade has seen a rapid increase of numerical simulation studies on photobioreactors (PBRs). Developments in computational fluid dynamics (CFD) and the availability of more powerful computers have paved the way for the modeling and designing ... Keywords: Computational fluid dynamics (CFD), Computer simulation, Microalgae, Photobioreactors

J. P. Bitog; I. -B. Lee; C. -G. Lee; K. -S. Kim; H. -S. Hwang; S. -W. Hong; I. -H. Seo; K. -S. Kwon; E. Mostafa

2011-05-01T23:59:59.000Z

304

Energy consumption and CO2emissions of Beijing heating system: based on a system dynamics model  

Science Conference Proceedings (OSTI)

Beijing is a typical North China city, and it uses about 15-18% of its total energy consumption for heating. The building construction industry is also a key source of CO2 emissions. This article, based on a system dynamics model, aims to simulate and ... Keywords: CO2 emissions, energy consumption, heating system, system dynamics

Hefeng Tong; Weishuang Qu

2011-11-01T23:59:59.000Z

305

Generating multimedia presentations that summarize the behavior of dynamic systems using a model-based approach  

Science Conference Proceedings (OSTI)

This article describes a knowledge-based method for generating multimedia descriptions that summarize the behavior of dynamic systems. We designed this method for users who monitor the behavior of a dynamic system with the help of sensor networks and ... Keywords: Behavior summarization, Data abstraction, Data-to-text system, Intelligent user interface, Multimedia presentation, Presentation model, Text-graphic coordination

Martin Molina; Victor Flores

2012-02-01T23:59:59.000Z

306

Sensory experience modifies spontaneous state dynamics in a large-scale barrel cortical model  

Science Conference Proceedings (OSTI)

Experimental evidence suggests that spontaneous neuronal activity may shape and be shaped by sensory experience. However, we lack information on how sensory experience modulates the underlying synaptic dynamics and how such modulation influences the ... Keywords: Barrel cortex, Large-scale model, STDP, Spontaneous dynamics

Elena Phoka; Mark Wildie; Simon R. Schultz; Mauricio Barahona

2012-10-01T23:59:59.000Z

307

Geothermal-district-heating assessment model for decision making  

DOE Green Energy (OSTI)

A methodology developed to assess the economic feasibility of district heating for any community in the United States is described. The overall philosophy which has guided its development is the conviction that district heating must be examined on a site-by-site basis. To support this approach, a set of extensive, in-house supporting data bases has been created and useful external data bases with national coverage have been identified. These data bases provide information at a sufficient level of detail to permit a first-cut examination of the district heating potential of a community without requiring outside data collection (allowing a substantial cost and time savings). The results of this blind look at a community permit a rapid, yet adequate estimate of district heating potential, costs, and energy savings. The data utilized in the initial examination can be supplemented or replaced by more detailed information obtained from on-site data collection, if the first results are promising. The fact that the data and methodology are computerized allows many locations within the community, alternate heat sources, ownership options, pipe technologies, etc. to be examined in a short period of time. The structure of the District Heating Model (DHM) (the methodology in computerized form) is described followed by a discussion of the application of the model to Provo, UT.

Reisman, A.

1981-11-01T23:59:59.000Z

308

Specification and Verification of Dynamics in Cognitive Agent Models  

E-Print Network (OSTI)

Within many domains, among which biological and cognitive areas, multiple interacting processes occur among agents with dynamics that are hard to handle. Current approaches to analyse the dynamics of such processes, often based on differential equations, are not always successful. As an alternative to differential equations, this paper presents the predicate logical Temporal Trace Language (TTL) for the formal specification and analysis of dynamic properties. This language supports the specification of both qualitative and quantitative aspects, and therefore subsumes specification languages based on differential equations. A software environment has been developed for TTL, that supports editing TTL properties and enables the formal verification of properties against a set of traces. The TTL environment proved its value in a number of projects within different domains. 1.

Tibor Bosse; Catholijn M. Jonker; Lourens Van Der Meij; Alexei Sharpanskykh; Jan Treur

2006-01-01T23:59:59.000Z

309

Heating dynamics of CO{sub 2}-laser irradiated silica particles with evaporative shrinking: Measurements and modeling  

SciTech Connect

The heating dynamics of CO{sub 2}-laser heated micron-sized particles were determined for temperatures <3500 K measured using infrared imaging. A coupled mass and energy conservation model is derived to predict single particle temperatures and sizes, which were compared with data from particles deposited on non-absorbing substrates to assess the relevant heat transfer processes. Analysis reveals substrate conduction dominates all other heat losses, while laser absorption determined from Mie theory is strongly modulated by particle evaporative shrinking. This study provides insights into the light coupling and heating of particle arrays where the material optical properties are temperature-dependent and particle size changes are significant.

Elhadj, S.; Qiu, S. R.; Stolz, C. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Monterrosa, A. M. [Department of Nuclear Engineering and Department of Materials Science and Engineering, University of California, Berkeley, California 94704 (United States)

2012-05-01T23:59:59.000Z

310

Thermo -Dynamic & -Kinetic Modeling to Quantify the Evolution of ...  

Science Conference Proceedings (OSTI)

The thermo-kinetic model is applied on various chemical compositions of type ... Application of the Phase-Field Model to Four-Phase Reactions in Ternary Alloys.

311

Dynamics of the Oil Transition: Modeling Capacity, Costs, and Emissions  

E-Print Network (OSTI)

extra-heavy oil and shale have zero Resource- Cost), whileof the Oil Transition: Modeling Capacity, Costs, andof the oil transition: modeling capacity, costs, and

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

312

Computational fluid dynamics for LNG vapor dispersion modeling: a key parameters study  

E-Print Network (OSTI)

The increased demand for liquefied natural gas (LNG) has led to the construction of several new LNG terminals in the United States (US) and around the world. To ensure the safety of the public, consequence modeling is used to estimate the exclusion distances. The purpose of having these exclusion distances is to protect the public from being reached by flammable vapors during a release. For LNG industry, the exclusion zones are determined by the half lower flammability limits (half LFL, 2.5% V/V). Since LNG vapors are heavier?than?air when released into atmosphere, it goes through stages, negative, neutral and positive buoyant effect. In this process, it may reach the half LFL. The primary objective of this dissertation is to advance the status of LNG vapor dispersion modeling, especially for complex scenarios (i.e. including obstacle effects). The most used software, box models, cannot assess these complex scenarios. Box models simulate the vapor in a free?obstacle environment. Due to the advancement in computing, this conservative approach has become questionable. New codes as computational fluid dynamics (CFD) have been proven viable and more efficient than box models. The use of such advance tool in consequence modeling requires the refinement of some of the parameters. In these dissertation, these parameters were identified and refine through a series of field tests at the Brayton Firefighter Training Field (BFTF) as part of the Texas A&M University System (TAMUS). A total of five tests contributed to this dissertation, which three of them were designed and executed by the LNG team of the Mary Kay O'Connor Process Safety Center (MKOPSC) and the financial support from BP Global SPU Gas (BP). The data collected were used as calibration for a commercial CFD code called CFX from ANSYS. Once the CFD code was tuned, it was used in a sensitivity analysis to assess the effects of parameters in the LFL distance and the concentration levels. The dissertation discusses also the validity range for the key parameters.

Cormier, Benjamin Rodolphe

2008-08-01T23:59:59.000Z

313

Quantifying Predictability Variations in a Low-Order Occan-Atmosphere Model: A Dynamical Systems Approach  

Science Conference Proceedings (OSTI)

A dynamical systems approach is used to quantify the predictability of weather and climatic states of a low order, moist general circulation model. The effects on predictability of incorporating a simple oceanic circulation are evaluated. The ...

Jon M. Nese; John A. Dutton

1993-02-01T23:59:59.000Z

314

Dynamic Models for the Subgrid-Scale Mixing of Reactants in Atmospheric Turbulent Reacting Flows  

Science Conference Proceedings (OSTI)

The effects of the subgrid scales on chemical transformations in large-eddy simulations of the convective atmospheric boundary layer (CBL) are investigated. Dynamic similarity subgrid-scale models are formulated and used to calculate the subgrid-...

Jean-François Vinuesa; Fernando Porté-Agel

2008-05-01T23:59:59.000Z

315

A Dynamic and Thermodynamic Foundation for Modeling the Moist Atmosphere with Parameterized Microphysics  

Science Conference Proceedings (OSTI)

Moist convection is an exquisite yet powerful participant in the creation of weather on our planet. To facilitate numerical modeling of weather systems in a moist atmosphere, a direct and consistent application of dynamic and thermodynamic ...

Katsuyuki V. Ooyama

2001-08-01T23:59:59.000Z

316

A Mechanism and Simple Dynamical Model of the North Atlantic Oscillation and Annular Modes  

Science Conference Proceedings (OSTI)

A simple dynamical model is presented for the basic spatial and temporal structure of the large-scale modes of intraseasonal variability and associated variations in the zonal index. Such variability in the extratropical atmosphere is known to be ...

Geoffrey K. Vallis; Edwin P. Gerber; Paul J. Kushner; Benjamin A. Cash

2004-02-01T23:59:59.000Z

317

Transport, Radiative, and Dynamical Effects of the Antarctic Ozone Hole: A GFDL “SKYHI” Model Experiment  

Science Conference Proceedings (OSTI)

The GFDL “SKYHI” general circulation model has been used to simulate the effect of the Antarctic “ozone hole” phenomenon on the radiative and dynamical environment of the lower stratosphere. Both the polar ozone destruction and photochemical ...

J. D. Mahlman; L. J. Umscheid; J. P. Pinto

1994-02-01T23:59:59.000Z

318

Modeling the Oceanic Circulation in the Area of the Strait of Sicily: The Remotely Forced Dynamics  

Science Conference Proceedings (OSTI)

In order to describe aspects of the baroclinic dynamics in the region of the Strait of Sicily a high-resolution multilayer numerical model has been implemented in a central Mediterranean region including the Tyrrhenian and the Ionian Seas. Three ...

Stefano Pierini; Angelo Rubino

2001-06-01T23:59:59.000Z

319

The Dynamics of an Explosively Developing Cyclone Simulated by a General Circulation Model  

Science Conference Proceedings (OSTI)

The synoptic structure and dynamics of an explosively developing winter extratropical cyclone simulated by NCAR’s CCM2 general circulation model is examined and compared with cyclones that have developed explosively in nature. The primary ...

Karen D. Walthorn; Phillip J. Smith

1998-11-01T23:59:59.000Z

320

Dynamic Model and Control of an Artificial Muscle Based on Contractile Polymers  

E-Print Network (OSTI)

A dynamic model and control system of an artificial muscle is presented. The artificial muscle is based on a contractile polymer gel which undergoes abrupt volume changes in response to variations in external conditions. ...

Brock, David L.

1991-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Dynamical Downscaling of Austral Summer Climate Forecasts over Southern Africa Using a Regional Coupled Model  

Science Conference Proceedings (OSTI)

The prediction skill of dynamical downscaling is evaluated for climate forecasts over southern Africa using the Advanced Research Weather Research and Forecasting (WRF) model. As a case study, forecasts for the December–February (DJF) season of ...

J. V. Ratnam; S. K. Behera; S. B. Ratna; C. J. de W. Rautenbach; C. Lennard; J.-J. Luo; Y. Masumoto; K. Takahashi; T. Yamagata

2013-08-01T23:59:59.000Z

322

Dynamical Origin of Low-Frequency Variability in a Highly Nonlinear Midlatitude Coupled Model  

Science Conference Proceedings (OSTI)

A novel mechanism of decadal midlatitude coupled variability, which crucially depends on the nonlinear dynamics of both the atmosphere and the ocean, is presented. The coupled model studied involves quasigeostrophic atmospheric and oceanic ...

S. Kravtsov; P. Berloff; W. K. Dewar; M. Ghil; J. C. McWilliams

2006-12-01T23:59:59.000Z

323

Using Multi-scale Dynamic Rupture Models to Improve Ground Motion...  

NLE Websites -- All DOE Office Websites (Extended Search)

Multi-scale Dynamic Rupture Models to Improve Ground Motion Estimates PI Name: Thomas Jordan PI Email: tjordan@usc.edu Institution: USC Allocation Program: ESP Allocation Hours at...

324

Simulating Competition and Coexistence between Plant Functional Types in a Dynamic Vegetation Model  

Science Conference Proceedings (OSTI)

The global distribution of vegetation is broadly determined by climate, and where bioclimatic parameters are favorable for several plant functional types (PFTs), by the competition between them. Most current dynamic global vegetation models (...

Vivek K. Arora; George J. Boer

2006-05-01T23:59:59.000Z

325

Some conservation issues for the dynamical cores of NWP and climate models  

Science Conference Proceedings (OSTI)

The rationale for designing atmospheric numerical model dynamical cores with certain conservation properties is reviewed. The conceptual difficulties associated with the multiscale nature of realistic atmospheric flow, and its lack of time-reversibility, ... Keywords: Climate simulation, Conservation, Weather prediction

J. Thuburn

2008-03-01T23:59:59.000Z

326

Lattice Boltzmann Models (LBM) for Two-phase Thermo-hydro-dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Lattice Boltzmann Models (LBM) for Two-phase Thermo-hydro-dynamics Speaker(s): Prashant Jain Date: October 15, 2009 - 12:00pm Location: 90-3122 Lattice Boltzmann Method (LBM) is...

327

Supercritical Dynamics of Baroclinic Disturbances in a Free-Surface Model  

Science Conference Proceedings (OSTI)

Nonlinear dynamics of unstable baroclinic disturbances are examined in the context of the Eady model modified by Ekman dissipation at the lower boundary while the upper boundary remains stress-free. Three approaches are used: the asymptotic ...

Suih-Hung Chou; Arthur Z. Loesch

1986-02-01T23:59:59.000Z

328

Application of Continuous Dynamic Grid Adaption Techniques to Meteorological Modeling. Part I: Basic Formulation and Accuracy  

Science Conference Proceedings (OSTI)

The continuous dynamic grid adaption (CDGA) technique developed in astrophysics and aeronautics is applied, to our knowledge, for the first time to meteorological modeling. The aim of CDGA is to improve the accuracy of numerical solutions of ...

Gary S. Dietachmayer; Kelvin K. Droegemeier

1992-08-01T23:59:59.000Z

329

Modeling the Pathways and Mean Dynamics of River Plume Dispersal in the New York Bight  

Science Conference Proceedings (OSTI)

This study investigates the dispersal of the Hudson River outflow across the New York Bight and the adjacent inner- through midshelf region. Regional Ocean Modeling System (ROMS) simulations were used to examine the mean momentum dynamics; the ...

Weifeng G. Zhang; John L. Wilkin; Robert J. Chant

2009-05-01T23:59:59.000Z

330

Kinetic Modeling and Assessment of Lime Pretreatment of Poplar Wood  

E-Print Network (OSTI)

Because of widespread availability, low cost, sustainability, and potential supply far greater than that of food crops, lignocellulosic biomass is one of the most promising feedstocks for producing biofuels through fermentation processes. Among lignocellulose choices, poplar wood is appealing because of high energy potential, above-average carbon mitigation potential, fast growth, and high yields. Lignocellulose structural features limit accessibility of enzymes or microorganisms. To overcome these limitations, pretreatment is required. Among several choices of pretreatment, lime pretreatment is preferred because lime is the cheapest alkali, safest to handle, easy to recover, and compatible with oxidants. The main effect of lime pretreatment is to degrade lignin, which occurs with good carbohydrate preservation and is enhanced with oxidants. Among several choices of oxidant, oxygen and air are preferred because of low cost and widespread availability. This study systematically assesses the effects of lime pretreatment on poplar wood using four different modes: long-term oxidative, long-term non-oxidative, short-term constant pressure, and short-term varying pressure. Long-term pretreatments use temperatures between 25 and 65° C, air if oxidant is used, and last several weeks. Short-term pretreatments use temperatures between 110 and 180° C, pressurized oxygen, and last several minutes to hours. Pretreatment was assessed on the basis of 3-day enzymatic digestibility using enzyme loadings of 15 FPU/g glucan in raw biomass. The results were used to recommend pretreatment conditions based on highest overall yield of glucan (after combined pretreatment and enzymatic hydrolysis) for each pretreatment mode. For each pretreatment mode, kinetic models for delignification and carbohydrates degradation were obtained and used to determine the conditions (temperature, pressure, and time) that maximize glucan preservation subjected to a target lignin yield. This study led to conclude that the most robust, and selective mode of lime pretreatment is varying pressure.

Sierra Ramirez, Rocio

2010-12-01T23:59:59.000Z

331

System dynamics model for simulation of the software inspection process  

Science Conference Proceedings (OSTI)

Repairing a defect in the late phases of software development can be a hundred times more expensive than finding and fixing it during the requirements and design phase. Software inspection is a technique that may be used to aid in the identification ... Keywords: defect detection, software inspection, system dynamics

Jailton Jr. De Sousa Coelho, José Luis Braga, Bernardo Giori Ambrósio

2013-08-01T23:59:59.000Z

332

Dynamical Model for Meson Production off Nucleon and Application to Neutrino-Nucleus Reactions  

SciTech Connect

I explain the Sato-Lee (SL) model and its extension to the neutrino-induced pion production off the nucleon. Then I discuss applications of the SL model to incoherent and coherent pion productions in the neutrino-nucleus scattering. I mention a further extension of this approach with a dynamical coupled-channels model developed in Excited Baryon Analysis Center of JLab.

Nakamura, Satoshi X. [Excited Baryon Analysis Center (EBAC), Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

2011-11-23T23:59:59.000Z

333

Dynamical modeling of transport in MOS structures containing silicon nanocrystals for memory applications  

Science Conference Proceedings (OSTI)

A compact model that can be used to reproduce both quasi-static and dynamic characteristics of basic MOS cells with embedded Si-nc is presented. The structure is modeled through a device-like complex matrix of tunnel junctions, resulting in a time-dependent ... Keywords: Flash memories, Nanocrystals, Nonvolatile memories, Silicon, Silicon nanocrystals, Transport modeling

Josep Carreras; O. Jambois; M. Perálvarez; Y. Lebour; B. Garrido

2008-12-01T23:59:59.000Z

334

A random walk approach to modeling the dynamics of the blogosphere  

Science Conference Proceedings (OSTI)

It is important to develop intuitive and tractable generative models to simulate the topological and temporal dynamics of the blogosphere because these models provide insights about its structural evolution. In such generative models, independent instances ... Keywords: blogosphere, network science, random walks

Muhammad Zubair Shafiq; Alex X. Liu

2011-05-01T23:59:59.000Z

335

Power System Aggregate Load Area Dynamic Modeling by Learning Based on WAMS  

Science Conference Proceedings (OSTI)

This paper is concerned with an investigation of a methodology using intelligent learning techniques based on WAMS to construct power system load area model. An aggregate load area dynamic model (ALADM) is proposed to represent large area loads of power ... Keywords: ALADM, Genetic algorithm, Load area modeling, Power system, Recursive least squares

Huimin Yang; Jinyu Wen

2009-05-01T23:59:59.000Z

336

Modeling and visualization of lifecycle building performance assessment  

Science Conference Proceedings (OSTI)

Lifecycle building performance assessment (LBPA) ensures that buildings perform and operate as intended during building lifecycle. Such assessment activities are typically multi-phase and multi-disciplinary, and generate large amounts of information ...

Ipek Gursel; Sevil Sariyildiz; Ömer Akin; Rudi Stouffs

2009-10-01T23:59:59.000Z

337

A Linear Stochastic Dynamical Model of ENSO. Part II: Analysis  

Science Conference Proceedings (OSTI)

In this study the behavior of a linear, intermediate model of ENSO is examined under stochastic forcing. The model was developed in a companion paper (Part I) and is derived from the Zebiak–Cane ENSO model. Four variants of the model are used ...

C. J. Thompson; D. S. Battisti

2001-02-01T23:59:59.000Z

338

Evaluating quantitative and qualitative models: An application for nationwide water erosion assessment in Ethiopia  

Science Conference Proceedings (OSTI)

This paper tests the candidacy of one qualitative response model and two quantitative models for a nationwide water erosion hazard assessment in Ethiopia. After a descriptive comparison of model characteristics the study conducts a statistical comparison ... Keywords: Model comparison, Qualitative response models, Quantitative models

B. G. J. S. Sonneveld; M. A. Keyzer; L. Stroosnijder

2011-10-01T23:59:59.000Z

339

Characteristics of identifying linear dynamic models from impulse response data using Prony analysis  

SciTech Connect

The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general rules-of-thumb'' for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.

Trudnowski, D.J.

1992-12-01T23:59:59.000Z

340

Characteristics of identifying linear dynamic models from impulse response data using Prony analysis  

SciTech Connect

The purpose of the study was to investigate the characteristics of fitting linear dynamic models to the impulse response of oscillatory dynamic systems using Prony analysis. Many dynamic systems exhibit oscillatory responses with multiple modes of oscillations. Although the underlying dynamics of such systems are often nonlinear, it is frequently possible and very useful to represent the system operating about some set point with a linear model. Derivation of such linear models can be done using two basic approaches: model the system using theoretical derivations and some linearization method such as a Taylor series expansion; or use a curve-fitting technique to optimally fit a linear model to specified system response data. Prony analysis belongs to the second class of system modeling because it is a method of fitting a linear model to the impulse response of a dynamic system. Its parallel formulation inherently makes it well suited for fitting models to oscillatory system data. Such oscillatory dynamic effects occur in large synchronous-generator-based power systems in the form of electromechanical oscillations. To study and characterize these oscillatory dynamics, BPA has developed computer codes to analyze system data using Prony analysis. The objective of this study was to develop a highly detailed understanding of the properties of using Prony analysis to fit models to systems with characteristics often encountered in power systems. This understanding was then extended to develop general ``rules-of-thumb`` for using Prony analysis. The general characteristics were investigated by performing fits to data from known linear models under controlled conditions. The conditions studied include various mathematical solution techniques; different parent system configurations; and a large variety of underlying noise characteristics.

Trudnowski, D.J.

1992-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects  

Science Conference Proceedings (OSTI)

In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods is less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the relative size of the transient storage zone and how it changes in the downstream direction, as well as the nature of hydrologic variability.

Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu; Basu, Nandita; Li, Hongyi; Wang, Shaowen

2012-06-30T23:59:59.000Z

342

THE PENA BLANCA NATURAL ANALOGUE PERFORMANCE ASSESSMENT MODEL  

SciTech Connect

The Nopal I uranium mine in the Sierra Pena Blanca, Chihuahua, Mexico serves as a natural analogue to the Yucca Mountain repository. The Pena Blanca Natural Analogue Performance Assessment Model simulates the mobilization and transport of radionuclides that are released from the mine and transported to the saturated zone. the Pena Blanca Natural Analogue Model uses probabilistic simulations of hydrogeologic processes that are analogous to the processes that occur at the Yucca Mountain site. The Nopal I uranium deposit lies in fractured, welded, and altered rhyolitic ash flow tuffs that overlie carbonate rocks, a setting analogous to the geologic formations at the Yucca Mountain site. The Nopal I mine site has the following characteristics as compared to the Yucca Mountain repository site. (1) Analogous source: UO{sub 2} uranium ore deposit = spent nuclear fuel in the repository; (2) Analogous geologic setting: fractured, welded, and altered rhyolitic ash flow tuffs overlying carbonate rocks; (3) Analogous climate: Semiarid to arid; (4) Analogous geochemistry: Oxidizing conditions; and (5) Analogous hydrogeology: The ore deposit lies in the unsaturated zone above the water table. The Nopal I deposit is approximately 8 {+-} 0.5 million years old and has been exposed to oxidizing conditions during the last 3.2 to 3.4 million years. The Pena Blanca Natural Analogue Model considers that the uranium oxide and uranium silicates in the ore deposit were originally analogous to uranium-oxide spent nuclear fuel. The Pena Blanca site has been characterized using field and laboratory investigations of its fault and fracture distribution, mineralogy, fracture fillings, seepage into the mine adits, regional hydrology, and mineralization that shows the extent of radionuclide migration. Three boreholes were drilled at the Nopal I mine site in 2003 and these boreholes have provided samples for lithologic characterization, water-level measurements, and water samples for laboratory analysis of the saturated zone water chemistry. The results of the field investigations and laboratory analyses of rock and water samples collected at Nopal I are used to calibrate the Pena Blanca Natural Analogue Model.

G.J. Saulnier Jr; W. Statham

2006-03-10T23:59:59.000Z

343

THE ASSESSMENT OF HIGH DYNAMIC RANGE LUMINANCE MEASUREMENTS WITH LED LIGHTING.  

E-Print Network (OSTI)

??This research investigates whether a High Dynamic Range Imaging (HDRI) technique can accurately capture luminance values of a single LED chip. Previous studies show that… (more)

Tyukhova, Yulia I.

2012-01-01T23:59:59.000Z

344

Dynamic Mercury Cycling Model Version 3.0 (D-MCM)  

Science Conference Proceedings (OSTI)

The Dynamic Mercury Cycling Model (D-MCM) predicts the cycling and fate of the major forms of mercury in lakes. The Dynamic Mercury Cycling Model (D-MCM) is a Windowsbased simulation model for personal computers. It predicts the cycling and fate of the major forms of mercury in lakes, including methylmercury, Hg(II), and elemental mercury. D-MCM is a time-dependent mechanistic model, designed to consider the most important physical, chemical and biological factors affecting fish mercury concentrations in...

2009-12-09T23:59:59.000Z

345

Chapter 18: Understanding the Developing Cellulosic Biofuels Industry through Dynamic Modeling  

DOE Green Energy (OSTI)

The purpose of this chapter is to discuss a system dynamics model called the Biomass Scenario Model (BSM), which is being developed by the U.S. Department of Energy as a tool to better understand the interaction of complex policies and their potential effects on the burgeoning cellulosic biofuels industry in the United States. The model has also recently been expanded to include advanced conversion technologies and biofuels (i.e., conversion pathways that yield biomass-based gasoline, diesel, jet fuel, and butanol), but we focus on cellulosic ethanol conversion pathways here. The BSM uses a system dynamics modeling approach (Bush et al., 2008) built on the STELLA software platform.

Newes, E.; Inman, D.; Bush, B.

2011-01-01T23:59:59.000Z

346

ERCOT's Dynamic Model of Wind Turbine Generators: Preprint  

SciTech Connect

By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.

Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.

2005-08-01T23:59:59.000Z

347

Convective Interaction with Dynamics in a Linear Primitive Equation Model  

Science Conference Proceedings (OSTI)

A new global atmosphere model purpose designed for climate studies is introduced. The model is solved in terms of the normal modes of the linearized primitive equations on a sphere, which allows use of long time steps without introducing ...

Richard Seager; Stephen E. Zebiak

1994-05-01T23:59:59.000Z

348

A Numerical Model for Low-Frequency Equatorial Dynamics  

Science Conference Proceedings (OSTI)

A fast, efficient numerical procedure for modeling the linear low-frequency motions on an equatorial beta plane is developed. The model is capable of simulating the seasonal and interannual variability in realistically shaped ocean basins forced ...

Mark A. Cane; Randall J. Patton

1984-12-01T23:59:59.000Z

349

System dynamics modelling of product carbon footprint life cycles for collaborative green supply chains  

Science Conference Proceedings (OSTI)

Governments, environmental groups and industry associations are reducing greenhouse gas emissions to insure environmental sustainability. Manufacturing plays an important role in economic development but is a main cause of global warming since production ... Keywords: economic input–output life cycle assessment, mass customisation, product carbon footprint, system dynamics

AmyJ. C. Trappey; CharlesV. Trappey; Chih-Tung Hsiao; JerryJ. R. Ou; Chin-Tsung Chang

2012-10-01T23:59:59.000Z

350

Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint  

SciTech Connect

Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.

2013-03-01T23:59:59.000Z

351

Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint  

SciTech Connect

Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.

2013-03-01T23:59:59.000Z

352

Ensemble Dynamics and Bred Vectors  

Science Conference Proceedings (OSTI)

The new concept of an ensemble bred vector (EBV) algorithm is introduced to assess the sensitivity of model outputs to changes in initial conditions for weather forecasting. The new algorithm is based on collective dynamics in essential ways. As ...

Nusret Balci; Anna L. Mazzucato; Juan M. Restrepo; George R. Sell

2012-07-01T23:59:59.000Z

353

Coupling GIS and LCA for biodiversity assessments of land use: Part 1: Inventory modeling  

E-Print Network (OSTI)

Strategic assessment of bioenergy development in the west:modeled the variation in bioenergy crop yields. Yield dataof biobased polymers and bioenergy: an analysis and system

Geyer, Roland; Stoms, David M.; Lindner, Jan P.; Davis, Frank W.; Wittstock, Bastian

2010-01-01T23:59:59.000Z

354

Dynamic  

Office of Legacy Management (LM)

Dynamic Dynamic , and Static , Res.ponse of the Government Oil Shale Mine at ' , . , Rifle, Colorado, to the Rulison Event. , . ; . . DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. p ( y c - - a 2-1 0 -4- REPORT AT (29-2) 914 USBM 1 0 0 1 UNITED STATES DEPARTMENT O F THE I NTERIOR BUREAU OF MINES e s.09 P. L. R U S S E L L RESEARCH D l RECTOR Februory 2, lB7O DYNAMIC AND STATIC RESPONSE 'OF THE GOVERNMENT OIL SHALE MINE A T RIFLE, COLORADO, T O THE, RULISON EVENT ORDER FROM CFSTl A S ~ B ~ &J C / This page intentionally left blank CONTENTS Page . . . . . . . . . . . . . . . . . . . . . . . . . H i s t o r i c . a l Des c r i p t i o n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction 3

355

Income Tax Evasion Dynamics: Evidence from an Agent-based Econophysics Model  

E-Print Network (OSTI)

We analyze income tax evasion dynamics in a standard model of statistical mechanics, the Ising model of ferromagnetism. However, in contrast to previous research, we use an inhomogeneous multi-dimensional Ising model where the local degrees of freedom (agents) are subject to a specific social temperature and coupled to external fields which govern their social behavior. This new modeling frame allows for analyzing large societies of four different and interacting agent types. As a second novelty, our model may reproduce results from agent-based models that incorporate standard Allingham and Sandmo tax evasion features as well as results from existing two-dimensional Ising based tax evasion models. We then use our model for analyzing income tax evasion dynamics under different enforcement scenarios and point to some policy implications.

Pickhardt, Michael

2011-01-01T23:59:59.000Z

356

DYNAMIC MODELLING OF AUTONOMOUS POWER SYSTEMS INCLUDING RENEWABLE POWER SOURCES.  

E-Print Network (OSTI)

(thermal, gas, diesel) and renewable (hydro, wind) power units. The objective is to assess the impact systems where the cost of conventional production is high. In recent years, the integration of wind energy is seen as an attractive alternative for fuel displacement. However, the intermittent nature of wind

Paris-Sud XI, Université de

357

Dynamic filter weights neural network model integrated with differential evolution for day-ahead price forecasting in energy market  

Science Conference Proceedings (OSTI)

In this paper a new dynamic model for forecasting electricity prices from 1 to 24h in advance is proposed. The model is a dynamic filter weight Adaline using a sliding mode weight adaptation technique. The filter weights for this neuron constitute of ... Keywords: Differential evolution, Dynamic filter weights neuron, Energy market, Local linear wavelet neural network, Sliding mode control

S. Chakravarty; P. K. Dash

2011-09-01T23:59:59.000Z

358

PRE-SW Dynamic Mercury Cycling Model (D-MCM)Version 4.0, Beta  

Science Conference Proceedings (OSTI)

The Dynamic Mercury Cycling Model (D-MCM) is a Windows™ based simulation model for personal computers. It predicts mercury cycling and bioaccumulation in aquatic systems.  Mercury forms include methylmercury, Hg(II), and elemental mercury. D-MCM is a time-dependent mechanistic model that can be applied deterministically or probabilistically. Version 4.0 is a major update to D-MCM.   The model can be applied in 1,2, and 3 dimensional applications for lakes, rivers, estuaries, ...

2013-09-17T23:59:59.000Z

359

Lawrence Livermore National Security Cost Model Functional Management Assessment  

Science Conference Proceedings (OSTI)

The scope of the Functional Management Assessment of the cost model included a review of the plan and progress of the Cost Model Review Team. The review focused on processes in place to ensure simplicity, compliance with cost accounting standards and indirect cost allocation methodology, and the change management plan. This was intended to be a high-level initial review in order to provide recommendations for a subsequent more comprehensive review. The single document reviewed by the team during the assessment was the Indirect Cost Recovery Model Review, which describes how the indirect rate restructure and new organizational structure have resulted in streamlined charging practices to better understand and strategically manage costs. ISSUE 1: The cost model focuses heavily on rate structure but not on cost management. Significant progress has been made to simplify the rate structure. The number of indirect rates has been reduced from 67 different indirect rates used under the prior contract to 32 rates in the first year of the LLNS contract, with a goal of further reduction to 16 for FY09. The reductions are being recommended by a broad-based Working Group driven by Lab leadership desiring a simplified rate structure that would make it easier to analyze the true cost of overhead, be viewed as equitable, and ensure appropriate use of Service, i.e., operations, Centers. This has been a real challenge due to the significant change in approach from one that previously involved a very complex rate structure. Under this prior approach, the goal was to manage the rates, and rates were established at very detailed levels that would 'shine the light' on pools of overhead costs. As long as rates stayed constant or declined, not as much attention tended to be given to them, particularly with so many pools to review (184 indirect rate pools in FY05). However, as difficult and important as simplifying the rate structure has been, the fundamental reason for the simplification is to make it easier to analyze the true cost of overhead so the costs can be effectively managed. For the current year, the overall the goal of keeping the total cost of an FTE to FY07 levels. This approach reflects the past practice of managing to rates rather than focusing on costs, although streamlined with the more simplified rate structure. Given all the challenges being faced with the contract transition, this was a reasonable interim tactic for dealing with the known cost increases such as fees and taxes. Nonetheless, in order to take full advantage of the opportunities that exist for making sound decisions for further reducing the rates themselves, the Laboratory needs to implement an ongoing and disciplined approach to understanding and managing overhead cost. ISSUE 2: The NIF has a significantly different rate structure than other Laboratory work. Because of its significant size and unique organizational structure as a major construction project, the National Ignition Facility (NIF) has indirect charges that vary from the norm. These variations were reviewed and approved by and disclosed to the NNSA in the Laboratory's past annual Disclosure Statements. In mid-FY 09, NIF will begin transition from a construction line item to an operational center. The reallocation of costs when this occurs could significantly impact the Laboratory's rates and rate structure planning for that transition from a cost- and rate- impact standpoint should begin soon. ISSUE 3: The new rate model must be finalized shortly in order to implement the model beginning in FY 09. As noted in Issue No.1, a Working Group has developed a simplified rate structure for the Lab to use for FY09. The Working Group has evaluated the cost impacts of the simplified rate structure at the major program level and identified a disparate impact in the Safeguards and Security area where a substantial increase in overhead cost allocation may need to be mitigated. The simplified rate structure will need to be approved by the Laboratory Director and issued within the Laboratory to formulate detailed bu

Tevis, J; Hirahara, J; Thomas, B; Mendez, M

2008-06-12T23:59:59.000Z

360

Dynamical forecast experiments with a baroclinic quasigeostrophic open ocean model  

Science Conference Proceedings (OSTI)

We report here on a series of numerical forecast experiments using a baroclinic quasigeostropic open ocean model. A simulation has been carried out to produce a model data set consisting of values of streamfunction and potential vorticity in four dimensions. This data set exhibits quasiturbulent characteristics similar to those of the mesoscale eddy field in the North Western Atlantic. The simulation has been carried out for several model years over many independent synoptic realizations.

Robert N. Miller; Allan R. Robinson

1984-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model  

SciTech Connect

Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.

Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People's Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)

2012-01-15T23:59:59.000Z

362

Dynamic Models for Wind Turbines and Wind Power Plants  

DOE Green Energy (OSTI)

The primary objective of this report was to develop universal manufacturer-independent wind turbine and wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. To determine how realistic model performance is, the performance of one of the models (doubly-fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.

Singh, M.; Santoso, S.

2011-10-01T23:59:59.000Z

363

Molecular Dynamics Modelling of Diffusional Formation of Titanium ...  

Science Conference Proceedings (OSTI)

Carbon diffusion is a crucial factor governing the response of titanium ... Adaptive phase-field modeling of grain growth in sintered uranium dioxide under high ...

364

Computation Modeling and Assessment of Nanocoatings for Ultra Supercritical Boilers  

Science Conference Proceedings (OSTI)

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 diffusion from the coating into the substrate. An effective diffusion barrier interlayer coating was developed to prevent inward Al diffusion. The fire-side corrosion test results showed that the nanocrystalline coatings with a minimum number of defects have a great potential in providing corrosion protection. The coating tested in the most aggressive environment showed no evidence of coating spallation and/or corrosion attack after 1050 hours exposure. In contrast, evidence of coating spallation in isolated areas and corrosion attack of the base metal in the spalled areas were observed after 500 hours. These contrasting results after 500 and 1050 hours exposure suggest that the premature coating spallation in isolated areas may be related to the variation of defects in the coating between the samples. It is suspected that the cauliflower-type defects in the coating were presumably responsible for coating spallation in isolated areas. Thus, a defect free good quality coating is the key for the long-term durability of nanocrystalline coatings in corrosive environments. Thus, additional process optimization work is required to produce defect-free coatings prior to development of a coating application method for production parts.

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

2011-06-21T23:59:59.000Z

365

Progress in coupling models of coastline and fluvial dynamics  

Science Conference Proceedings (OSTI)

The morphology and depositional history of wave-influenced deltas reflects the interplay between the fluvial and coastal domains. Here we present initial results of the coupling of stand-alone coastal and terrestrial models within the Community Surface ... Keywords: CSDMS, Coastal morphodynamics, Component Modeling Tool (CMT), Sediment variability, Wave-influenced deltas

Andrew D. Ashton; Eric W. H. Hutton; Albert J. Kettner; Fei Xing; Jisamma Kallumadikal; Jaap Nienhuis; Liviu Giosan

2013-04-01T23:59:59.000Z

366

Dynamical instabilities in density-dependent hadronic relativistic models  

Science Conference Proceedings (OSTI)

Unstable modes in asymmetric nuclear matter (ANM) at subsaturation densities are studied in the framework of relativistic mean-field density-dependent hadron models. The size of the instabilities that drive the system are calculated and a comparison with results obtained within the nonlinear Walecka model is presented. The distillation and antidistillation effects are discussed.

Santos, A. M.; Brito, L.; Providencia, C. [Centro de Fisica Teorica, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal)

2008-04-15T23:59:59.000Z

367

Estimating Potential Evaporation from Vegetated Surfaces for Water Management Impact Assessments Using Climate Model Output  

Science Conference Proceedings (OSTI)

River basin managers concerned with maintaining water supplies and mitigating flood risk in the face of climate change are taking outputs from climate models and using them in hydrological models for assessment purposes. While precipitation is the ...

Victoria A. Bell; Nicola Gedney; Alison L. Kay; Roderick N. B. Smith; Richard G. Jones; Robert J. Moore

2011-10-01T23:59:59.000Z

368

Uncertainty Propagation of Regional Climate Model Precipitation Forecasts to Hydrologic Impact Assessment  

Science Conference Proceedings (OSTI)

A Monte Carlo framework is adopted for propagating uncertainty in dynamically downscaled seasonal forecasts of area-averaged daily precipitation to associated streamflow response calculations. Daily precipitation is modeled as a mixture of two ...

Phaedon C. Kyriakidis; Norman L. Miller; Jinwon Kim

2001-04-01T23:59:59.000Z

369

Mathematical modeling of irreversible dynamic deformation, micro- and macrofracture of materials and structures  

National Nuclear Security Administration (NNSA)

7: Material Phase Transition, Modeling, and Others 7: Material Phase Transition, Modeling, and Others Mathematical Modeling of Irreversible Dynamic Deformation, Micro- and Macrofracture of Materials and Structures P. P. Zakharov and A. B. Kiselev All-Russia Research Institute of Automatics, Moscow 125412, Russia Thermomechanical processes, which proceed in deformable solids under intensive dynamic loading, consist of mechanical, thermal and structural ones, which correlate themselves. The structural processes involve the formation, motion and interaction of defects in metallic crystals, phase transitions, the breaking of bonds between molecules in polymers, the accumulation of microstructural damages (pores, cracks), etc. Irreversible deformations, zones of adiabatic shear and microfractures are caused by these

370

Converter Program: PSADD Dictionary for Dynamics Model, Version 2.0  

Science Conference Proceedings (OSTI)

This manual contains a listing of the PSADD dictionary for PSS/E dynamics models. The format of this dictionary is the same as that used for the "main" PSADD. Wherever possible, dictionary names and data types are the same as those used in the "main" PSADD. Please note that not all of the PSS/E dynamics models have been included in this dictionary and are convertible by the CONVERTER program. EPRI advisors and PTI engineers selected the models for inclusion based on the perceived "usefulness" of the mode...

2000-07-13T23:59:59.000Z

371

Using neural networks and cellular automata for modelling intra-urban land-use dynamics  

Science Conference Proceedings (OSTI)

Empirical models designed to simulate and predict urban land-use change in real situations are generally based on the utilization of statistical techniques to compute the land-use change probabilities. In contrast to these methods, artificial neural ... Keywords: Cellular automata, Fuzzy similarity measures, Land-use dynamics, Neural networks, Town planning, Urban modelling

C. M. Almeida; J. M. Gleriani; E. F. Castejon; B. S. Soares-Filho

2008-09-01T23:59:59.000Z

372

Computational fluid dynamics modelling of sewage sludge mixing in an anaerobic digester  

Science Conference Proceedings (OSTI)

In this paper, the development of a computational fluid dynamics (CFD) model to simulate the mechanical mixing of sewage sludge at laboratory scale is reported. The paper recommends a strategy for modelling mechanically mixed sewage sludge at laboratory ... Keywords: Biogas, CFD, Digestion, Energy, Non-Newtonian fluid, Sewage sludge, Turbulence

J. Bridgeman

2012-02-01T23:59:59.000Z

373

Eddy Dynamics in a Primitive Equation Model: Sensitivity to Horizontal Resolution and Friction  

Science Conference Proceedings (OSTI)

A primitive equation model of an idealized ocean basin, driven by simple, study wind and buoyancy forcing at the surface, is used to study the dynamics of mesoscale eddies. Model statistics of a six-year integration using a fine grid (1/6° × 0.2°)...

Claus W. Böning; Reinhard G. Budich

1992-04-01T23:59:59.000Z

374

A dynamic object-oriented architecture approach to ecosystem modeling and simulation.  

SciTech Connect

Modeling and simulation in support of adaptive ecosystem management can be better accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem-modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques, through a geographic information system (GIS)-based framework. The Strategic Environmental Research and Development Program (SERDP) sponsored the development of IDLAMS. Initially built upon a GIS framework, IDLAMS is migrating to an object-oriented (OO) architectural framework. An object-oriented architecture is more flexible and modular. It allows disparate applications and dynamic models to be integrated in a manner that minimizes (or eliminates) the need to rework or recreate the system as new models are added to the suite. In addition, an object-oriented design makes it easier to provide run-time feedback among models, thereby making it a more dynamic tool for exploring and providing insight into the interactions among ecosystem processes. Finally, an object-oriented design encourages the reuse of existing technology because OO-IDLAMS is able to integrate disparate models, databases, or applications executed in their native languages. Reuse is also accomplished through a structured approach to building a consistent and reusable object library. This reusability can substantially reduce the time and effort needed to develop future integrated ecosystem simulations.

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

1999-04-09T23:59:59.000Z

375

Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll-a concentration  

E-Print Network (OSTI)

Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll form 17 October 2000; accepted 1 June 2001 Abstract A remotely sensed image of Loch Leven, a shallow in the remotely sensed image. It is proposed that CFD modelling benefits the interpretation of remotely sensed

376

Dynamic–Thermodynamic Sea Ice Model: Ridging and Its Application to Climate Study and Navigation  

Science Conference Proceedings (OSTI)

A dynamic–thermodynamic sea ice model with the ocean mixed layer forced by atmospheric data is used to investigate spatial and long-term variability of the sea ice cover in the Arctic basin. The model satisfactorily reproduces the averaged main ...

Sergey V. Shoutilin; Alexander P. Makshtas; Motoyoshi Ikeda; Alexey V. Marchenko; Roman V. Bekryaev

2005-09-01T23:59:59.000Z

377

Smoothed particle hydrodynamics non-Newtonian model for ice-sheet and ice-shelf dynamics  

Science Conference Proceedings (OSTI)

We propose a new three-dimensional smoothed particle hydrodynamics (SPH) non-Newtonian model to study coupled ice-sheet and ice-shelf dynamics. Most existing ice-sheet numerical models use grid-based Eulerian discretizations, and are usually restricted ... Keywords: Grounding line, Ice sheet, Non-Newtonian fluid, Smoothed particle hydrodynamics

W. Pan, A. M. Tartakovsky, J. J. Monaghan

2013-06-01T23:59:59.000Z

378

Design of model reference adaptive sliding mode tracking controllers for mismatched uncertain dynamic systems  

Science Conference Proceedings (OSTI)

Based on the Lyapunov stability theorem, a model reference adaptive sliding mode control scheme is proposed in this paper for a class of multi-input multi-output (MIMO) dynamic systems with mismatched model uncertainties and external disturbances in ... Keywords: Lyapunov stability theorem, adaptive control, mismatched perturbations, sliding mode control

Chih-Chiang Cheng; Hung-An Chen; Jia-Ming Hsiao

2009-06-01T23:59:59.000Z

379

User's Guide to DYNASTORE: A Computer Model for Quantifying Dynamic Energy Storage Benefits  

Science Conference Proceedings (OSTI)

The DYNASTORE model's unique new capabilities enable it to quantify certain disaggregated benefits of energy storage technologies via a chronological production cost model. Because of this, it can provide a useful tool for proper evaluation and operation of such technologies, as well as knowledge of associated dynamic benefits.

1990-12-01T23:59:59.000Z

380

A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu  

E-Print Network (OSTI)

played a role during the crisis period. 1 Introduction The energy industry provides electrical powerA Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu , Anthony E. Brockwell of supply and demand equilibrium. The model includes latent supply and demand curves, which may vary over

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381

A heuristic method to minimise the chattering problem in dynamic mathematical two-phase flow models  

Science Conference Proceedings (OSTI)

This paper introduces the chattering problem in dynamic mathematical two-phase flow models. The real system object of study is also introduced, the DISS test facility, a parabolic-trough solar power plant using as heat transfer fluid the steam-water ... Keywords: Chattering, Heuristic methods, Modelling and simulation, Parabolic-trough solar power plant, Two-phase flow, Zeno phenomenon

J. Bonilla; L. J. Yebra; S. Dormido

2011-09-01T23:59:59.000Z

382

Assessment of GPU computational enhancement to a 2D flood model  

Science Conference Proceedings (OSTI)

This paper presents a study of the computational enhancement of a Graphics Processing Unit (GPU) enabled 2D flood model. The objectives are to demonstrate the significant speedup of a new GPU-enabled full dynamic wave flood model and to present the effect ... Keywords: 2D flood model, CUDA, Flood simulation, GPU programming

Alfred J. Kalyanapu; Siddharth Shankar; Eric R. Pardyjak; David R. Judi; Steven J. Burian

2011-08-01T23:59:59.000Z

383

A new analytic-adaptive model for EGS assessment, development...  

Open Energy Info (EERE)

center in Nevada with REA250. State Nevada Objectives Develop and apply: (1) a Geologic Heat Exchanger (GHE) model, (2) a life-cycle model, and (3) a total system model. The GHE...

384

Modeling land-surface/atmosphere dynamics for CHAMMP  

SciTech Connect

Project progress is described on a DOE CHAMP project to model the land-surface/atmosphere coupling in a heterogeneous environment. This work is a collaboration between scientists at Iowa State University and the University of New Hampshire. Work has proceeded in two areas: baseline model coupling and data base development for model validation. The core model elements (land model, atmosphere model) have been ported to the Principal Investigator's computing system and baseline coupling has commenced. The initial target data base is the set of observations from the FIFE field campaign, which is in the process of being acquired. For the remainder of the project period, additional data from the region surrounding the FIFE site and from other field campaigns will be acquired to determine how to best extrapolate results from the initial target region to the rest of the globe. In addition, variants of the coupled model will be used to perform experiments examining resolution requirements and coupling strategies for land-atmosphere coupling in a heterogeneous environment.

Gutowski, W.J. Jr.

1993-01-01T23:59:59.000Z

385

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

DOE Green Energy (OSTI)

This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.

Wayman, E. N.; Sclavounos, P. D.; Butterfield, S.; Jonkman, J.; Musial, W.

2006-03-01T23:59:59.000Z

386

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

SciTech Connect

This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.

Wayman, E. N.; Sclavounos, P. D.; Butterfield, S.; Jonkman, J.; Musial, W.

2006-03-01T23:59:59.000Z

387

Advanced Modeling of Renewable Energy Market Dynamics: May 2006  

SciTech Connect

This report documents a year-long academic project, presenting selected techniques for analysis of market growth, penetration, and forecasting applicable to renewable energy technologies. Existing mathematical models were modified to incorporate the effects of fiscal policies and were evaluated using available data. The modifications were made based on research and classification of current mathematical models used for predicting market penetration. An analysis of the results was carried out, based on available data. MATLAB versions of existing and new models were developed for research and policy analysis.

Evans, M.; Little, R.; Lloyd, K.; Malikov, G.; Passolt, G.; Arent, D.; Swezey, B.; Mosey, G.

2007-08-01T23:59:59.000Z

388

Modeling Exposure to Persistent Chemicals in Hazard and Risk Assessment  

E-Print Network (OSTI)

Research Council (NRC). 2007. Models in Environmentallimited or not available (NRC, 2007). The use of models hasthe late 19th century (NRC, 2007). In the area of transport

Cowan-Ellsberry, Christina E.

2010-01-01T23:59:59.000Z

389

Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions  

SciTech Connect

Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the stage of the adjacent Columbia River, coupled with a heterogeneous hydraulic conductivity distribution, leads to considerable variations in vertical hydraulic gradients. These variations, in turn, create intraborehole flows in fully-screened (6.5 m) observation wells with frequently alternating upward and downward movement. This phenomenon, in conjunction with a highly permeable aquifer formation and small horizontal hydraulic gradients, makes modeling analysis and model calibration a formidable challenge. Groundwater head data alone were insufficient to define the flow model boundary conditions, and the movement of the tracer was highly sensitive to the dynamics of the flow field. This study shows that model calibration can be significantly improved by explicitly considering (a) dynamic flow model boundary conditions and (b) intraborehole flow. The findings from this study underscore the difficulties in interpreting tracer tests and understanding solute transport under highly dynamic flow conditions.

Ma, Rui; Zheng, Chunmiao; Tonkin, Matthew J.; Zachara, John M.

2011-04-01T23:59:59.000Z

390

Simulation of Tailrace Hydrodynamics Using Computational Fluid Dynamics Models  

DOE Green Energy (OSTI)

This report investigates the feasibility of using computational fluid dynamics (CFD) tools to investigate hydrodynamic flow fields surrounding the tailrace zone below large hydraulic structures. Previous and ongoing studies using CFD tools to simulate gradually varied flow with multiple constituents and forebay/intake hydrodynamics have shown that CFD tools can provide valuable information for hydraulic and biological evaluation of fish passage near hydraulic structures. These studies however are incapable of simulating the rapidly varying flow fields that involving breakup of the free-surface, such as those through and below high flow outfalls and spillways. Although the use of CFD tools for these types of flow are still an active area of research, initial applications discussed in this report show that these tools are capable of simulating the primary features of these highly transient flow fields.

Cook, Chris B; Richmond, Marshall C

2001-05-01T23:59:59.000Z

391

Dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydration Hydration Water on Rutile Studied by Backscattering Neutron Spectroscopy and Molecular Dynamics Simulation E. Mamontov,* ,† D. J. Wesolowski, ‡ L. Vlcek, § P. T. Cummings, §,| J. Rosenqvist, ‡ W. Wang, ⊥ and D. R. Cole ‡ Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, Chemical Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, Department of Chemical Engineering, Vanderbilt UniVersity, NashVille, Tennessee 37235-1604, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6496, and EnVironmental Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6036 ReceiVed: December 20, 2007; ReVised Manuscript ReceiVed: June 4, 2008 The high energy resolution, coupled with the wide dynamic range, of the new backscattering

392

Modeling Equilibrium Dynamics of the Benguela Current System  

Science Conference Proceedings (OSTI)

The Regional Ocean Modeling System (ROMS) is used to systematically investigate equilibrium conditions and seasonal variations of the Benguela system at a resolution of 9 km, including both the large-scale offshore flow regime and the ...

Jennifer Veitch; Pierrick Penven; Frank Shillington

2010-09-01T23:59:59.000Z

393

Extended-Range Probability Forecasts Based on Dynamical Model Output  

Science Conference Proceedings (OSTI)

A probability forecast has advantages over a deterministic forecast as the former offers information about the probabilities of various possible future states of the atmosphere. As physics-based numerical models find their success in modern ...

Jianfu Pan; Huug van den Dool

1998-12-01T23:59:59.000Z

394

Dynamical Forecast Experiments with a Barotropic Open Ocean Model  

Science Conference Proceedings (OSTI)

The initial/boundary value problem for the barotropic version of a quasi-geostrophic open ocean model which requires normal flow everywhere on the boundary and vorticity on the inflow is studied. Parameter dependencies and sensitivities are ...

A. R. Robinson; D. B. Haidvogel

1980-12-01T23:59:59.000Z

395

Exploring Gravity and Gravitational Wave Dynamics Part II: Gravity Models  

Science Conference Proceedings (OSTI)

The need for a new gravity model may explain anomalous behavior exhibited by several recent experiments described in Part I. Although Newtonian gravity is adequate for predicting the motion of celestial bodies

P. A. Murad

2007-01-01T23:59:59.000Z

396

Mathematical Modeling of Fluid Dynamics and Vessel Vibration in ...  

Science Conference Proceedings (OSTI)

Direct Numerical Simulation of Inclusion Turbulent Deposition at Liquid ... Flow and Shrinkage Pipe Formation on Macrosegregation of Investment Cast -TiAl Alloys ... Numerical Modeling of the Interaction between a Foreign Particle an ...

397

Final Technical Report for "Collaborative Research: Regional climate-change projections through next-generation empirical and dynamical models"  

SciTech Connect

This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) models for gaining insight into the underlying dynamics in observational data and general circulation model (GCM) simulations. Using coupled O-A ICMs, we have identified a new mechanism of interdecadal climate variability, involving the midlatitude oceans mesoscale eddy field and nonlinear, persistent atmospheric response to the oceanic anomalies. A related decadal mode is also identified, associated with the oceans thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR model developments and software to strengthen two key pillars of support for the development and application of climate models for climate change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from climate models to applications, in order to inform societal adaptation strategies to climate change at the regional scale, including model calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-model ensembles. Our main results from the grant consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling specifically within the non-stationary climate change context together with the development of parallelized software; application of NHMMs to downscaling of rainfall projections over India; identification and analysis of decadal climate signals in data and models; and, studies of climate variability in terms of the dynamics of atmospheric flow regimes. Each of these project components is elaborated on below, followed by a list of publications resulting from the grant.

Robertson, A.W.; Ghil, M.; Kravtsov, K.; Smyth, P.J.

2011-04-08T23:59:59.000Z

398

Final Technical Report for "Collaborative Research: Regional climate-change projections through next-generation empirical and dynamical models"  

SciTech Connect

This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) models for gaining insight into the underlying dynamics in observational data and general circulation model (GCM) simulations. Using coupled O-A ICMs, we have identified a new mechanism of interdecadal climate variability, involving the midlatitude oceansâ?? mesoscale eddy field and nonlinear, persistent atmospheric response to the oceanic anomalies. A related decadal mode is also identified, associated with the oceansâ?? thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR model developments and software to strengthen two key pillars of support for the development and application of climate models for climate change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from climate models to applications, in order to inform societal adaptation strategies to climate change at the regional scale, including model calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-model ensembles. Our main results from the grant consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling specifically within the non-stationary climate change context together with the development of parallelized software; application of NHMMs to downscaling of rainfall projections over India; identification and analysis of decadal climate signals in data and models; and, studies of climate variability in terms of the dynamics of atmospheric flow regimes. Each of these project components is elaborated on below, followed by a list of publications resulting from the grant.

Kravtsov, S.; Robertson, A. W.; Ghil, M.; Smyth, P. J.

2011-04-08T23:59:59.000Z

399

Internal cycle modeling and environmental assessment of multiple cycle consumer products  

Science Conference Proceedings (OSTI)

Highlights: Black-Right-Pointing-Pointer Dynamic flow models are presented for remanufactured, reused or recycled products. Black-Right-Pointing-Pointer Early loss and stochastic return are included for fast and slow cycling products. Black-Right-Pointing-Pointer The reuse-to-input flow ratio (Internal Cycle Factor, ICF) is determined. Black-Right-Pointing-Pointer The cycle rate, which is increasing with the ICF, monitors eco-performance. Black-Right-Pointing-Pointer Early internal cycle losses diminish the ICF, the cycle rate and performance. - Abstract: Dynamic annual flow models incorporating consumer discard and usage loss and featuring deterministic and stochastic end-of-cycle (EOC) return by the consumer are developed for reused or remanufactured products (multiple cycle products, MCPs), including fast and slow cycling, short and long-lived products. It is shown that internal flows (reuse and overall consumption) increase proportionally to the dimensionless internal cycle factor (ICF) which is related to environmental impact reduction factors. The combined reuse/recycle (or cycle) rate is shown capable for shortcut, albeit effective, monitoring of environmental performance in terms of waste production, virgin material extraction and manufacturing impacts of all MCPs, a task, which physical variables (lifetime, cycling frequency, mean or total number of return trips) and conventional rates, via which environmental policy has been officially implemented (e.g. recycling rate) cannot accomplish. The cycle rate is shown to be an increasing (hyperbolic) function of ICF. The impact of the stochastic EOC return characteristics on total reuse and consumption flows, as well as on eco-performance, is assessed: symmetric EOC return has a small, positive effect on performance compared to deterministic, while early shifted EOC return is more beneficial. In order to be efficient, environmental policy should set higher minimum reuse targets for higher trippage MCPs. The results may serve for monitoring, flow accounting and comparative eco-assessment of MCPs. They may be useful in identifying reachable and efficient reuse/recycle targets for consumer products and in planning return via appropriate labelling and digital coding for enhancing environmental performance, while satisfying consumer demand.

Tsiliyannis, C.A., E-mail: anion@otenet.gr [ANION Environmental Ltd., 26 Lykoudi Str., Athens 11141 (Greece)

2012-01-15T23:59:59.000Z

400

Synchronized Phasor Data for Analyzing Wind Power Plant Dynamic Behavior and Model Validation  

DOE Green Energy (OSTI)

The U.S. power industry is undertaking several initiatives that will improve the operations of the power grid. One of those is the implementation of 'wide area measurements' using phasor measurement units (PMUs) to dynamically monitor the operations and the status of the network and provide advanced situational awareness and stability assessment. This project seeks to obtain PMU data from wind power plants and grid reference points and develop software tools to analyze and visualize synchrophasor data for the purpose of better understanding wind power plant dynamic behaviors under normal and contingency conditions.

Wan, Y. H.

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Assimilation of Altimeter Data into a Quasigeostrophic Model of the Gulf Stream System Part I: Dynamical Considerations  

Science Conference Proceedings (OSTI)

The dynamical consequences of constraining a numerical model with sea surface height data have been investigated. The model used for this study is a quasigeostrophic model of the Gulf Stream region. The data that have been assimilated are maps of ...

Antonietta Capotondi; Paola Malanotte-Rizzoli; William R. Holland

1995-06-01T23:59:59.000Z

402

Development of dynamic models of reactive distillation columns for simulation and determination of control  

E-Print Network (OSTI)

Dynamic models of a reactive distillation column have been developed and implemented in this work. A model describing the steady state behavior of the system has been built in a first step. The results from this steady state model have been compared to data provided from an industrial collaborator and the reconciled model formed the basis for the development of a dynamic model. Four controlled and four manipulated variables have been determined in a subsequent step and step tests for the manipulated variables were simulated. The data generated by the step responses was used for fitting transfer functions between the manipulated and the controlled variables. RGA analysis was performed to find the optimal pairing for controller design. Feedback controllers of PID type were designed between the paired variables found from RGA and the controllers were implemented on the column model. Both servo and regulatory problems have been considered and tested.

Chakrabarty, Arnab

2004-12-01T23:59:59.000Z

403

Development of microbial-enzyme-mediated decomposition model parameters through steady-state and dynamic analyses  

Science Conference Proceedings (OSTI)

We developed a Microbial-ENzyme-mediated Decomposition (MEND) model, based on the Michaelis-Menten kinetics, that describes the dynamics of physically defined pools of soil organic matter (SOC). These include particulate, mineral-associated, dissolved organic matter (POC, MOC, and DOC, respectively), microbial biomass, and associated exoenzymes. The ranges and/or distributions of parameters were determined by both analytical steady-state and dynamic analyses with SOC data from the literature. We used an improved multi-objective parameter sensitivity analysis (MOPSA) to identify the most important parameters for the full model: maintenance of microbial biomass, turnover and synthesis of enzymes, and carbon use efficiency (CUE). The model predicted an increase of 2 C (baseline temperature =12 C) caused the pools of POC-Cellulose, MOC, and total SOC to increase with dynamic CUE and decrease with constant CUE, as indicated by the 50% confidence intervals. Regardless of dynamic or constant CUE, the pool sizes of POC, MOC, and total SOC varied from 8% to 8% under +2 C. The scenario analysis using a single parameter set indicates that higher temperature with dynamic CUE might result in greater net increases in both POC-Cellulose and MOC pools. Different dynamics of various SOC pools reflected the catalytic functions of specific enzymes targeting specific substrates and the interactions between microbes, enzymes, and SOC. With the feasible parameter values estimated in this study, models incorporating fundamental principles of microbial-enzyme dynamics can lead to simulation results qualitatively different from traditional models with fast/slow/passive pools.

Wang, Gangsheng [ORNL; Post, Wilfred M [ORNL; Mayes, Melanie [ORNL

2013-01-01T23:59:59.000Z

404

Dynamic modeling of a single-stage downward firing, entrained flow gasifier  

SciTech Connect

The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.

Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.

2012-01-01T23:59:59.000Z

405

Double Modelling of the Dynamic of Activities in Rural Municipalities  

E-Print Network (OSTI)

Land use choices and activity prevalence in a selected territory are determined by individual preferences constrained by the characteristic of the analysed zone: population density, soil properties, urbanization level and other similar factors can drive individuals to make different kind of decisions about their occupations. Different approaches can be used to describe land use change, occupation prevalence and their reciprocal inter-relation. In this paper we describe two different kinds of approaches: an agent based model, centred on individual choices and an aggregated model describing the evolution of activity prevalence in terms of coupled differential equation. We use and we compare the two models to analyse the effect of territorial constraints, like the lack of employment in determined sectors, on the possible activity prevalence scenarios.

Ternes, S; Huet, S; Deffuant, G

2009-01-01T23:59:59.000Z

406

Alternating-phase focusing: A model to study nonlinear dynamics  

Science Conference Proceedings (OSTI)

We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.

Sagalovsky, L.; Delayen, J.R.

1992-09-01T23:59:59.000Z

407

Alternating-phase focusing: A model to study nonlinear dynamics  

SciTech Connect

We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.

Sagalovsky, L.; Delayen, J.R.

1992-01-01T23:59:59.000Z

408

Radiation MHD modeling of a proposed dynamic hohlraum  

SciTech Connect

In this paper we report 2D radiation magnetohydrodynamic simulations of a dynamic hohlraum target designed to be driven by the Z accelerator at Sandia National Laboratory, Albuquerque New Mexico. Z generates currents up 20 MA with a rise time of 100 ns and peak electrical power of 40 TW. In this design we attempt to reduce the effects of magneto-Rayleigh Taylor (RT) modes by using a distributed initial density profile. Earlier work showed that ``tailoring`` the initial density profile could reduce the sheath acceleration and the number of e-foldings that the RT instability grows during the implosion . As the sheath moves in radially, fresh material is swept up or ``snow plowed``, providing a back pressure that counters the J x B force. A special profile can be found in which the unstable outer surface of the sheath implodes at constant velocity, reducing the classical growth rate to zero, although residual Richtmeyer-Meshkov type instability (instability of the snow-plow shock front) may be present. In practice, it is hard to create tailored initial density profiles due to the difficulty of machining and otherwise manipulating very low density materials. It becomes easier to manufacture these complex targets as the current, energy and load mass increase with large drivers. Z is the first fast pulse power device with enough energy to consider loads of this type.

Hammer, J.H. [Lawrence Livermore National Lab., CA (United States); De Groot, J.S. [Lawrence Livermore National Lab., CA (United States)|California Univ., Davis, CA (United States); Tabak, M.; Toor, A.; Zimmerman, G.B. [Lawrence Livermore National Lab., CA (United States)

1997-07-01T23:59:59.000Z

409

Onverter Center of Gravity and Tilting Torque Dynamic Model Simulation  

Science Conference Proceedings (OSTI)

Using SolidWorks software to3D solid modeling of steelmaking converter and liquid steel to get their center of gravity coordinates, so as to optimize the location of the trunnion, that used to determine the best location of the converter trunnion. Based ... Keywords: Converter, Optimization, Tilting, Torque

Lichen Li, Yunfeng Liu, Shaoqing Ren, Tongqing Li

2012-07-01T23:59:59.000Z

410

A Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae  

E-Print Network (OSTI)

of biodiesel. In order to improve large- scale, industrial culturing systems, the development of math- ematical in microalgae, thereby spanning multiple time scales. The properties of the model are investigated under quasi been devoted to enhancing lipid production, from which biodiesel can be derived. Lipid productivity can

411

Behavioral dynamics on the web: Learning, modeling, and prediction  

Science Conference Proceedings (OSTI)

The queries people issue to a search engine and the results clicked following a query change over time. For example, after the earthquake in Japan in March 2011, the query japan spiked in popularity and people issuing the query were more likely ... Keywords: Behavioral analysis, predictive behavioral models

Kira Radinsky; Krysta M. Svore; Susan T. Dumais; Milad Shokouhi; Jaime Teevan; Alex Bocharov; Eric Horvitz

2013-07-01T23:59:59.000Z

412

Dynamical, Statistical–Dynamical, and Multimodel Ensemble Forecasts of Australian Spring Season Rainfall  

Science Conference Proceedings (OSTI)

The prediction skill of the Australian Bureau of Meteorology dynamical seasonal forecast model Predictive Ocean Atmosphere Model for Australia (POAMA) is assessed for probabilistic forecasts of spring season rainfall in Australia and the ...

Eun-Pa Lim; Harry H. Hendon; David L. T. Anderson; Andrew Charles; Oscar Alves

2011-03-01T23:59:59.000Z

413

A Comparison of Two Types of Atmospheric Transport Models—Use of Observed Winds Versus Dynamically Predicted Winds  

Science Conference Proceedings (OSTI)

Dynamic and kinematic trajectory Models were used to diagnose long-range transport during a 24-b period of the NEROS (1979) field study. The dynamic model consisted of a three-dimensional primitive equation model which predicted winds on a 25-km ...

Thomas T. Warner; Roderick R. Fizz; Nelson L. Seaman

1983-03-01T23:59:59.000Z

414

A dynamic battery model for co-design in cyber-physical systems Fumin Zhang, Zhenwu Shi  

E-Print Network (OSTI)

A dynamic battery model for co-design in cyber-physical systems Fumin Zhang, Zhenwu Shi School, Georgia 30332 Email: wolf@ece.gatech.edu Abstract We introduce a dynamic battery model that describes the variations of the capacity of a battery under time varying discharge current. This model supports a co

Zhang, Fumin

415

Informatic Tools for Assessment of Data Completeness for Model ...  

Science Conference Proceedings (OSTI)

First Principles Modeling of Shape Memory Alloy Magnetic Refrigeration Materials ... of Lithium Battery Materials LiMPO4 (M = Mn, Fe, Co, and Ni): A Comparative ... Forming-Crush Simulation Optimization Using Internal State Variable Model.

416

Assessment of Solution Uncertainties in Single-Column Modeling Frameworks  

Science Conference Proceedings (OSTI)

Single-column models (SCMs) have been extensively promoted in recent years as an effective means to develop and test physical parameterizations targeted for more complex three-dimensional climate models. Although there are some clear advantages ...

James J. Hack; John A. Pedretti

2000-01-01T23:59:59.000Z

417

Assessment of reduced mechanisms using One Dimensional Stochastic Turbulence model  

E-Print Network (OSTI)

Thermochemical information Semi-empirical methods Chemical kinetics information Detail chemical kinetics mechanism Transport model Transport parameters Computational simulation

Chien, Li-Chun

2010-01-01T23:59:59.000Z

418

Dynamic models of residential segregation: brief review, analytical resolution and study of the introduction of coordination  

E-Print Network (OSTI)

In his 1971's Dynamic Models of Segregation paper, the economist Thomas C. Schelling showed that a small preference for one's neighbors to be of the same color could lead to total segregation, even if total segregation does not correspond to individual preferences and to a residential configuration maximizing the collective utility. The present work is aimed at deepening the understanding of the properties of dynamic models of segregation based on Schelling's hypotheses. Its main contributions are (i) to offer a comprehensive and up-to-date review of this family of models; (ii) to provide an analytical solution to the most general form of this model under rather general assumptions; to the best of our knowledge, such a solution did not exist so far; (iii) to analyse the effect of two devices aimed at decreasing segregation in such a model.

Grauwin, S; Jensen, P

2009-01-01T23:59:59.000Z

419

Models used to assess the performance of photovoltaic systems.  

DOE Green Energy (OSTI)

This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization. Energy storage plays an important role in reducing PV intermittency and battery storage models are used to understand the best configurations and technologies to store PV generated electricity. Other researcher's models used by SNL are discussed including some widely known models that incorporate algorithms developed at SNL. There are other models included in the discussion that are not used by or were not adopted from SNL research but may provide some benefit to researchers working on PV array performance, hybrid system models and energy storage. The paper is organized into three sections to describe the different software models as applied to photovoltaic performance, hybrid systems, and battery storage. For each model, there is a description which includes where to find the model, whether it is currently maintained and any references that may be available. Modeling improvements underway at SNL include quantifying the uncertainty of individual system components, the overall uncertainty in modeled vs. measured results and modeling large PV systems. SNL is also conducting research into the overall reliability of PV systems.

Stein, Joshua S.; Klise, Geoffrey T.

2009-12-01T23:59:59.000Z

420

Technology Assessment and Application Guide for Micro Dynamic Voltage Restorer (DVR)  

Science Conference Proceedings (OSTI)

This report describes and documents the construction, performance, and application of a micro dynamic voltage restorer (DVR). The system is a prototype developed by the researchers at the University of São Paulo located in Brazil, South America. The report describes the operation and performance evaluation results of the Micro DVR and issues related to application and installation.

2008-12-19T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites  

E-Print Network (OSTI)

Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading have been analyzed. Elastic moduli and thermal coefficient of expansion are calculated and their variation with diameter and length is investigated. In particular, the nanotubes are modeled using 3D elastic beam finite elements with six degrees of freedom at each node. The difficulty in modeling multi walled nanotubes is the van der Waal's forces between adjacent layers which are geometrically non linear in nature. These forces are modeled using truss elements. The nanotube-polymer interface in a nano-composite is modeled on a similar basis. While performing the molecular dynamic simulations, the geometric optimization is performed initially to obtain the minimized configuration and then the desired temperature is attained by rescaling the velocities of carbon atoms in the nanotube. Results show that the Young's modulus increases with tube diameter in molecular mechanics whereas decreases in molecular dynamics since the inter-atomic potential due to chemical reactions between the atoms is taken into consideration in molecular dynamics unlike in molecular mechanics.

Gaddamanugu, Dhatri

2009-05-01T23:59:59.000Z

422

INSTABILITY-DRIVEN DYNAMICAL EVOLUTION MODEL OF A PRIMORDIALLY FIVE-PLANET OUTER SOLAR SYSTEM  

SciTech Connect

Over the last decade, evidence has mounted that the solar system's observed state can be favorably reproduced in the context of an instability-driven dynamical evolution model, such as the 'Nice' model. To date, all successful realizations of instability models have concentrated on evolving the four giant planets onto their current orbits from a more compact configuration. Simultaneously, the possibility of forming and ejecting additional planets has been discussed, but never successfully implemented. Here we show that a large array of five-planet (two gas giants + three ice giants) multi-resonant initial states can lead to an adequate formation of the outer solar system, featuring an ejection of an ice giant during a phase of instability. Particularly, our simulations demonstrate that the eigenmodes that characterize the outer solar system's secular dynamics can be closely matched with a five-planet model. Furthermore, provided that the ejection timescale of the extra planet is short, orbital excitation of a primordial cold classical Kuiper Belt can also be avoided in this scenario. Thus, the solar system is one of many possible outcomes of dynamical relaxation and can originate from a wide variety of initial states. This deems the construction of a unique model of solar system's early dynamical evolution impossible.

Batygin, Konstantin; Brown, Michael E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Betts, Hayden, E-mail: kbatygin@gps.caltech.edu [Polytechnic School, Pasadena, CA 91106 (United States)

2012-01-15T23:59:59.000Z

423

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

Science Conference Proceedings (OSTI)

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

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

2011-10-01T23:59:59.000Z

424

Dynamic balances within tropical plumes in a global barotropic model  

E-Print Network (OSTI)

Tropical plumes are a common synoptic scale feature over the Eastern Pacific associated with subtropical jet and ITCZ intensifications. Because of data sparseness, operational analysis has yielded little information of the details of the tropical plume formation process. Tropical plumes have been simulated in a global 200 mb shallow water model with a realistic basic state (Blackwell 1990). Diagnostic budgets were calculated based on model output for absolute vorticity, divergence, and kinetic energy. Also, the movement of the zero absolute vorticity isopleth during plume formation is examined. This information is compared for cases with plume formation, without plume formation, and the basic state. Budget results indicate the convergent forcing center, when located near a strong absolute vorticity gradient, creates an equatorial Rossby wave source. This source generates a large scale, quasi-stationary equatorial Rossby wave which, if located near the ambient eastern Pacific trough, strengthens this trough into the tropics. As the trough strengthens, it displaces the vorticity gradient equatorward into the cmvergence forcing region. This vorticity gradient encroaches upon the forcing region and creates a second Rossby wave source. This generates a second, smaller scale Rossby wave which propagates to the northeast along the axis of strong vorticity gradient. This Rossby wave is highly divergent in nature, due to the model's small Rossby radius of deformation. The accompanying train of convergence/divergence centers distorts the potential trough to create significant cross contour flow, which accelerates the subtropical jet to the east of the trough, resulting in a tropical plume. This study indicates the Rossby wave and accompanying cross contour and ageostrophic flow adequately explain the formation of all three key tropical plume features.

Vest, Gerry Wilson

1993-01-01T23:59:59.000Z

425

Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics  

E-Print Network (OSTI)

We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions which are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate the model supernova ejecta are typically composed of about 0.1-0.25 Msun of silicon group elements, 0.9-1.2 Msun of iron group elements, and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg-shaped with the axis ratio ~1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon-group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ~1.3-1.5 10^51 erg.

Tomasz Plewa

2006-11-24T23:59:59.000Z

426

A new modeling approach of STLF with integrated dynamics mechanism and based on the fusion of dynamic optimal neighbor phase points and ICNN  

Science Conference Proceedings (OSTI)

Based on the time evolution similarity principle of the topological neighbor phase points in the Phase Space Reconstruction (PSR), a new modeling approach of Short-Term Load Forecasting (STLF) with integrated dynamics mechanism and based on the fusion ...

Zhisheng Zhang; Yaming Sun; Shiying Zhang

2006-05-01T23:59:59.000Z

427

Modeling two-spin dynamics in a noisy environment  

SciTech Connect

We describe how the effect of charge noise on a pair of spins coupled via the exchange interaction can be calculated by modeling charge fluctuations as a random telegraph noise process using probability density functions. We develop analytic expressions for the time-dependent superoperator of a pair of spins as a function of fluctuation amplitude and rate. We show that the theory can be extended to include multiple fluctuators, in particular, spectral distributions of fluctuators. These superoperators can be included in time-dependent analyses of the state of spin systems designed for spintronics or quantum information processing to determine the decohering effects of exchange fluctuations.

Testolin, M. J.; Hollenberg, L. C. L. [Centre for Quantum Computer Technology, School of Physics, University of Melbourne, Victoria 3010 (Australia); Cole, J. H. [Centre for Quantum Computer Technology, School of Physics, University of Melbourne, Victoria 3010 (Australia); Institut fuer Theoretische Festkoerperphysik und DFG-Center for Functional Nanostructures (CFN), Universitaet Karlsruhe, 76128 Karlsruhe (Germany)

2009-10-15T23:59:59.000Z

428

Modelling water dynamics with DNDC and DAISY in a soil of the North China Plain: A comparative study  

Science Conference Proceedings (OSTI)

The performance of the DNDC and Daisy model to simulate the water dynamics in a floodplain soil of the North China Plain was tested and compared. While the DNDC model uses a simple cascade approach, the Daisy model applies the physically based Richard's ... Keywords: China, DNDC, Daisy, Model comparison, Model evaluation, Modelling, North China Plain, Soil water content

Roland Kröbel; Qinping Sun; Joachim Ingwersen; Xinping Chen; Fusuo Zhang; Torsten Müller; Volker Römheld

2010-04-01T23:59:59.000Z

429

IMAGE: An integrated model to assess the greenhouse effect  

SciTech Connect

This book is the result of a research project entitled Reference Function for Global Air Pollution CO{sub 2}. It deals with the description of a computer simulation model of the greenhouse effect. This model, IMAGE, tries to capture the fundamentals of the complex problem of climate change in a simplified way. The model is a multidisciplinary product and is based on knowledge from disciplines as economics, atmospheric chemistry, marine and terrestrial biogeochemistry, ecology, climatology, and glaciology. This book might be of interest to any one working in the broad field of climate change. Furthermore, it can be useful for model builders, simulation experts, and mathematicians.

Rotmans, J.

1990-01-01T23:59:59.000Z

430

Nonlinear Dynamical Model of Regime Switching Between Conventions and Business Cycles  

E-Print Network (OSTI)

We introduce and study a non-equilibrium continuous-time dynamical model of the price of a single asset traded by a population of heterogeneous interacting agents in the presence of uncertainty and regulatory constraints. The model takes into account (i) the price formation delay between decision and investment by the second-order nature of the dynamical equations, (ii) the linear and nonlinear mean-reversal or their contrarian in the form of speculative price trading, (iii) market friction, (iv) uncertainty in the fundamental value which controls the amplitude of mispricing, (v) nonlinear speculative momentum effects and (vi) market regulations that may limit large mispricing drifts. We find markets with coexisting equilibrium, conventions and business cycles, which depend on (a) the relative strength of value-investing versus momentum-investing, (b) the level of uncertainty on the fundamental value and (c) the degree of market regulation. The stochastic dynamics is characterized by nonlinear geometric rando...

Yukalov, V I; Yukalova, E P

2008-01-01T23:59:59.000Z

431

Adaptive Construction Modelling Within Whole Building Dynamic Simulation  

E-Print Network (OSTI)

............................ vii List of Symbols .......................... ix Chapter 1: Introduction ....................... 1 1.1 The need for building energy simulation ............... 1 1.2 The evolution of building energy simulation tools ............ 2 1.3 The need for accurate building fabric modelling ............ 4 1.4 Objective and outline of the present work ............... 5 Chapter 2: Review of Heat and Moisture Transport within Building Materials ...... 8 2.1 Building energy simulation ................... 8 2.1.1 Heat conduction .................... 8 2.1.2 Mass diffusion .................... 16 2.2 Adaptive gridding ...................... 18 2.3 Thermophysical properties ................... 23 2.4 Combined heat and moisture transport ................ 27 2.4.1 Moisture transport in porous building materials .......... 29 2.4.2 Differential equations for combined heat and moisture transport ..... 33 Chapter 3: Adaptive Building Fabric Gridding ................ 37 3.1 Math...

Abdullatif Nakhi Degree; Abdullatif E. Nakhi; Wife Masoumah

1995-01-01T23:59:59.000Z

432

Simulating animal spirits in actor-based environmental models  

Science Conference Proceedings (OSTI)

As a first step towards extending the MADIAM model reported previously to a model hierarchy MADIAMS (Multi-Actor Dynamic Integrated Assessment Model System), we upgrade the basic economic model M2 of the three model levels M1-M3 of MADIAMS to include ... Keywords: Actor-based model, Climate change, Instability, Integrated assessment, System dynamics

Klaus Hasselmann, Dmitry V. Kovalevsky

2013-06-01T23:59:59.000Z

433

Model for Assessment and Remediation of Sediments (MARS): Four Case Studies  

Science Conference Proceedings (OSTI)

The Model for the Assessment and Remediation of Sediments (MARS) provides a new tool for modeling contaminated surface water sediments. With quantitative screening level analysis capabilities, the model is tailored for application to contaminated sediment sites and is applicable to tidal and non-tidal rivers. MARS consists of three interconnected hydrodynamic, sediment, and chemical fate and transport models. Together, these models simulate the fate and transport of organic compounds, while allowing eval...

2004-12-07T23:59:59.000Z

434

Conceptual design of an integrated technology model for carbon policy assessment.  

SciTech Connect

This report describes the conceptual design of a technology choice model for understanding strategies to reduce carbon intensity in the electricity sector. The report considers the major modeling issues affecting technology policy assessment and defines an implementable model construct. Further, the report delineates the basis causal structure of such a model and attempts to establish the technical/algorithmic viability of pursuing model development along with the associated analyses.

Backus, George A.; Dimotakes, Paul E. (NASA Jet Propulsion Laboratory, Pasadena, CA)

2011-01-01T23:59:59.000Z

435

Intrinsic dynamics of heart regulatory systems on short time-scales: from experiment to modelling  

E-Print Network (OSTI)

We discuss open problems related to the stochastic modeling of cardiac function. The work is based on an experimental investigation of the dynamics of heart rate variability (HRV) in the absence of respiratory perturbations. We consider first the cardiac control system on short time scales via an analysis of HRV within the framework of a random walk approach. Our experiments show that HRV on timescales of less than a minute takes the form of free diffusion, close to Brownian motion, which can be described as a non-stationary process with stationary increments. Secondly, we consider the inverse problem of modeling the state of the control system so as to reproduce the experimentally observed HRV statistics of. We discuss some simple toy models and identify open problems for the modelling of heart dynamics.

Khovanov, I A; McClintock, P V E; Stefanovska, A

2009-01-01T23:59:59.000Z

436

Treatment of Parameter and Modeling Uncertainty for Probabilistic Risk Assessments  

Science Conference Proceedings (OSTI)

Both the industry and the U.S. Nuclear Regulatory Commission (NRC) incorporate risk concepts and techniques into activities for effective risk management. The NRC is using probabilistic risk assessment (PRA) in its regulatory activities in a manner that promotes consistency, predictability, and efficiency in the performance of the NRCs roles of risk manager and protector of public health and safety. The nuclear industry uses PRA to identify and manage risks, as a tool to promote efficient regulatory inte...

2008-12-19T23:59:59.000Z

437

Implementing and assessing computational modeling in introductory mechanics  

E-Print Network (OSTI)

Students taking introductory physics are rarely exposed to computational modeling. In a one-semester large lecture introductory calculus-based mechanics course at Georgia Tech, students learned to solve physics problems using the VPython programming environment. During the term 1357 students in this course solved a suite of fourteen computational modeling homework questions delivered using an online commercial course management system. Their proficiency with computational modeling was evaluated in a proctored environment using a novel central force problem. The majority of students (60.4%) successfully completed the evaluation. Analysis of erroneous student-submitted programs indicated that a small set of student errors explained why most programs failed. We discuss the design and implementation of the computational modeling homework and evaluation, the results from the evaluation and the implications for instruction in computational modeling in introductory STEM courses.

Caballero, Marcos D; Schatz, Michael F

2011-01-01T23:59:59.000Z

438

Assessing the Skill of an All-Season Statistical Forecast Model for the Madden–Julian Oscillation  

Science Conference Proceedings (OSTI)

Motivated by an attempt to augment dynamical models in predicting the Madden–Julian oscillation (MJO), and to provide a realistic benchmark to those models, the predictive skill of a multivariate lag-regression statistical model has been ...

Xianan Jiang; Duane E. Waliser; Matthew C. Wheeler; Charles Jones; Myong-In Lee; Siegfried D. Schubert

2008-06-01T23:59:59.000Z

439

Dynamic thermal modelling of a power integrated circuit with the application of structure functions  

Science Conference Proceedings (OSTI)

This paper presents dynamic thermal analyses of a power integrated circuit with a cooling assembly. The investigations are based on the examination of the cumulative and differential structure functions obtained from the circuit cooling curves recorded ... Keywords: Contact thermal resistance, Heat transfer coefficient, Structure function, Thermal modelling and simulation

Marcin Janicki; Jedrzej Banaszczyk; Gilbert De Mey; Marek Kaminski; Bjorn Vermeersch; Andrzej Napieralski

2009-07-01T23:59:59.000Z

440

A Scalable Modeling Technique to Estimate Dynamic Thermal Design Power of Datapath Intensive Designs  

Science Conference Proceedings (OSTI)

In this paper, a power modeling approach for the estimation of dynamic power under Thermal Design Power (TDP1) for datapath intensive designs is proposed. Early estimation of TDP is crucial for the design of thermal and cooling solutions of a chip and ...

Prashant Agrawal; Srinivasa R. STG; Ajit N. Oke; Saurabh Vijay

2007-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Topic dynamics: an alternative model of bursts in streams of topics  

Science Conference Proceedings (OSTI)

For some time there has been increasing interest in the problem of monitoring the occurrence of topics in a stream of events, such as a stream of news articles. This has led to different models of bursts in these streams, i.e., periods of elevated ... Keywords: burst, hierarchy, momentum, pubmed, topic dynamic

Dan He; D. Stott Parker

2010-07-01T23:59:59.000Z

442

Dynamic Model Validation of PV Inverters under Short-Circuit Conditions  

Science Conference Proceedings (OSTI)

Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of PV deployment. Residential and commercial rooftop installations are connected to the distribution network, large-scale installation PV power ... Keywords: photovoltaic, PV, dynamic model, validation, solar PV inverter, renewables

E. Muljadi, M. Singh, R. Bravo, V. Gevorgian

2013-04-01T23:59:59.000Z

443

Dynamic Policy Modeling for Chronic Diseases: Metaheuristic-Based Identification of Pareto-Optimal Screening Strategies  

Science Conference Proceedings (OSTI)

We present a risk-group oriented chronic disease progression model embedded within a metaheuristic-based optimization of the policy variables. Policy-makers are provided with Pareto-optimal screening schedules for risk groups by considering cost and ... Keywords: chronic disease policy analysis, decision analysis, dynamic resource allocation, health care, metaheuristics, multicriteria optimization, prevention

Marion S. Rauner; Walter J. Gutjahr; Kurt Heidenberger; Joachim Wagner; Joseph Pasia

2010-09-01T23:59:59.000Z

444

Dynamic Modeling and Simulation of Hybrid Power Systems Based on Renewable Energy  

Science Conference Proceedings (OSTI)

This paper describes dynamic modeling and simulation results of a renewable energy based hybrid power system. The paper focuses on the combination of solar cell (SC), wind turbine (WT), fuel cell (FC) and ultra-capacitor (UC) systems for power generation. ... Keywords: fuel cell, hybrid power system, renewable energy, solar cell, ultra-capacitor, wind turbine

Teng-Fa Tsao; Po-Hung Chen; Hung-Cheng Chen

2009-10-01T23:59:59.000Z

445

Dynamic modeling and multivariable control of organic Rankine cycles in waste heat utilizing processes  

Science Conference Proceedings (OSTI)

In this paper, the dynamics of organic Rankine cycles (ORCs) in waste heat utilizing processes is investigated, and the physical model of a 100 kW waste heat utilizing process is established. In order to achieve both transient performance and steady-state ... Keywords: Linear quadratic regulator, Organic Rankine cycles, Process control

Jianhua Zhang; Wenfang Zhang; Guolian Hou; Fang Fang

2012-09-01T23:59:59.000Z

446

The Role of the Indonesian Throughflow on ENSO Dynamics in a Coupled Climate Model  

Science Conference Proceedings (OSTI)

The effects of the Indonesian Throughflow (ITF) on ENSO dynamics are studied in a coupled climate model by comparing two simulations, one with an open ITF and the other with a closed ITF. Closing the ITF results in an El Niño–like climate state ...

A. Santoso; W. Cai; M. H. England; S. J. Phipps

2011-02-01T23:59:59.000Z

447

Experiences with early life-cycle performance modeling for architecture assessment  

Science Conference Proceedings (OSTI)

In this paper we describe our preliminary experiences of a performance modeling "Blending" approach for early life-cycle architecture assessment and risk mitigation in a large enterprise integration project. The goal was to use performance modeling to ... Keywords: blended performance modeling, early life-cycle risk mitigation

Paul C. Brebner

2012-06-01T23:59:59.000Z

448

Mathematical Modeling to Study the Dynamics of A Diatomic Molecule N2 in Water  

E-Print Network (OSTI)

In the present work an attempt has been made to study the dynamics of a diatomic molecule N2 in water. The proposed model consists of Langevin stochastic differential equation whose solution is obtained through Euler's method. The proposed work has been concluded by studying the behavior of statistical parameters like variance in position, variance in velocity and covariance between position and velocity. This model incorporates the important parameters like acceleration, intermolecular force, frictional force and random force.

Sharma, Nitin

2010-01-01T23:59:59.000Z

449

A resource-constrained profit-based dynamic order management model  

Science Conference Proceedings (OSTI)

This research extends the Available-to-Promise (ATP) concept to include both capacity and profitability considerations in a two-level supply chain. The model in study is referred in practice as Profitable-to-Promise (PTP) ... Keywords: ATP, DSS, available-to-, capacity, decision models, decision support systems, demand management, dynamic order management, production planning, profitability, profitable-to-, promise, resource constraints, resource planning, two-level supply chains

Elias T. Kirche; Rajesh Srivastava

2007-11-01T23:59:59.000Z

450

Assessment of reduced mechanisms using One Dimensional Stochastic Turbulence model  

E-Print Network (OSTI)

turbulence model for a syngas jet flame. Proceeding of FallKerstein 2002), a turbulent syngas (CO/H2/NO) jet flame wasand DNS results of the syngas jet flame was recently done

Chien, Li-Chun

2010-01-01T23:59:59.000Z

451

Fuzzy integrated vulnerability assessment model for critical facilities in combating the terrorism  

Science Conference Proceedings (OSTI)

Critical facility vulnerability assessment is a highly complex strategic activity in combating the terrorism and necessitates a structured quantified methodology to support the decision-making process in defense planning. In the system perspective, the ... Keywords: Airport, Fuzzy Cognitive Maps (FCM), Fuzzy integrated vulnerability assessment model (FIVAM), Fuzzy set theory, Interdependency, Simple Multi-Attribute Rating Technique (SMART), Terrorism

Ilker Akgun; Ahmet Kandakoglu; Ahmet Fahri Ozok

2010-05-01T23:59:59.000Z

452

A simplified physical model for assessing solar radiation over Brazil using GOES 8 visible imagery  

E-Print Network (OSTI)

A simplified physical model for assessing solar radiation over Brazil using GOES 8 visible imagery; published 30 January 2004. [1] Solar radiation assessment by satellite is constrained by physical.4 and 1.3 MJ mÃ?2 for daily irradiation). A comparison with monthly means from about 80 automatic weather

453

The Development and Assessment of a Model-, Grid-, and Basin-Independent Tropical Cyclone Detection Scheme  

Science Conference Proceedings (OSTI)

A novel approach to tropical cyclone (TC) detection in coarse-resolution numerical model data is introduced and assessed. This approach differs from traditional detectors in two main ways. First, it was developed and tuned using 20 yr of ECMWF ...

K. J. Tory; S. S. Chand; R. A. Dare; J. L. McBride

2013-08-01T23:59:59.000Z

454

Parameterization of PBL Processes in an Atmospheric General Circulation Model: Description and Preliminary Assessment  

Science Conference Proceedings (OSTI)

This paper presents the basic features of a newly developed planetary boundary layer (PBL) parameterization, and the performance assessment of a version of the University of California, Los Angeles (UCLA), Atmospheric General Circulation Model (...

Celal S. Konor; Gabriel Cazes Boezio; Carlos R. Mechoso; Akio Arakawa

2009-03-01T23:59:59.000Z

455

Assessing 1D Atmospheric Solar Radiative Transfer Models: Interpretation and Handling of Unresolved Clouds  

Science Conference Proceedings (OSTI)

The primary purpose of this study is to assess the performance of 1D solar radiative transfer codes that are used currently both for research and in weather and climate models. Emphasis is on interpretation and handling of unresolved clouds. ...

H. W. Barker; G. L. Stephens; P. T. Partain; J. W. Bergman; B. Bonnel; K. Campana; E. E. Clothiaux; S. Clough; S. Cusack; J. Delamere; J. Edwards; K. F. Evans; Y. Fouquart; S. Freidenreich; V. Galin; Y. Hou; S. Kato; J. Li; E. Mlawer; J.-J. Morcrette; W. O'Hirok; P. Räisänen; V. Ramaswamy; B. Ritter; E. Rozanov; M. Schlesinger; K. Shibata; P. Sporyshev; Z. Sun; M. Wendisch; N. Wood; F. Yang

2003-08-01T23:59:59.000Z

456

To develop a dynamic model of a collector loop for purpose of improved control of solar heating and cooling. Final technical report. [TRNSYS code  

DOE Green Energy (OSTI)

The program objectives were to (1) assess the feasibility of using the TRNSYS computer code for solar heating and cooling control studies and modify it wherever possible, and (2) develop a new dynamic model of the solar collector which reflects the performance of the collector under transient conditions. Also, the sensitivity of the performance of this model to the various system parameters such as collector time constants, flow rates, turn-on and turn-off temperature set points, solar insolation, etc., was studied. Results are presented and discussed. (WHK)

Herczfeld, P.R.; Fischl, R.

457

DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS  

SciTech Connect

In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in which flow regime transition occurs.

X. Wang; X. Sun; H. Zhao

2011-09-01T23:59:59.000Z

458

Integrated dynamic and simulation model on coupled closed-loop workstation capacity controls in a multi-workstation production system  

Science Conference Proceedings (OSTI)

In this paper, a dynamic model coupled with a simulation model is introduced to control a multi-workstation production system such that a given performance measure is achieved. In particular, we consider closed loop capacity controls for regulating WIP ...

Tao Wu; Leyuan Shi; Benjamin Quirt; N. A. Duffie

2008-12-01T23:59:59.000Z

459

Tropical Atlantic Decadal Oscillation and Its Potential Impact on the Equatorial Atmosphere–Ocean Dynamics: A Simple Model Study  

Science Conference Proceedings (OSTI)

Simple coupled atmosphere–ocean models are used to study the potential influence of the tropical Atlantic Ocean decadal oscillation on the equatorial Atlantic atmosphere–ocean dynamics. Perturbing the model tropical Atlantic at the extratropics (...

Sang-Ki Lee; Chunzai Wang

2008-01-01T23:59:59.000Z

460

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

Science Conference Proceedings (OSTI)

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.

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

2010-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics models assessing" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

An investigation into the use of biokinetic models when assessing intakes of plutonium  

E-Print Network (OSTI)

The goal of internal dosimetry is to assess the dose to an individual from an intake of a radionuclide. This usually encompasses assessing the intake amount based on some form of bioassay measurement used with a biokinetic model. There are many published biokinetic models that describe the transfer of radionuclides throughout the body. It would be beneficial at times if one could interchange certain biokinetic models with another to assess an intake based on bioassay data to save time and make calculations simpler. This research compared the daily excretion rates by interchanging widely used biokinetic models in different combinations. These model combinations were then used to assess an unknown intake of a case study. It was shown that the ICRP-30 and ICRP-66 respiratory tract models can only be interchanged at specific times post intake to give similar excretion results from an inhalation intake. It is feasible to interchange the ICRP-67 plutonium systemic model or the newer Luciani and Polig plutonium systemic model to assess an intake based on fecal bioassay data, but not urine bioassay data for ingestion intakes. It is not feasible to interchange the systemic models when assessing intakes from a wound or injection. Using different combinations of biokinetic models predicted intakes within 30% for a case study which included a relatively long inhalation chronic intake followed by a much shorter chronic inhalation intake. It was shown that the predicted initial chronic intake for each combination of models gave fecal excretion values which deviated the most from the worker's fecal bioassay data. This could mean that the biokinetic models yield inaccurate excretion rates for long chronic intakes.

Hrycushko, Brian Andrew

2008-08-01T23:59:59.000Z

462

Assessing Future Changes in the East Asian Summer Monsoon Using CMIP3 Models: Results from the Best Model Ensemble  

Science Conference Proceedings (OSTI)

Future changes in the East Asian summer monsoon (EASM) have been estimated from the six best-performing models in phase 3 of the Coupled Model Intercomparison Project (CMIP3) included in the Fourth Assessment Report (AR4) of the Intergovernmental ...

Kyong-Hwan Seo; Jung Ok

2013-03-01T23:59:59.000Z

463

A co-modelling process of social and natural dynamics on the isle of Ouessant: Sheep, turf and bikes  

Science Conference Proceedings (OSTI)

An interdisciplinary team has applied the multi-agent system formalism to study shrub encroachment in the Biosphere Reserve on the isle of Ouessant. The main goals were (1) to understand vegetation dynamics, and (2) to represent how main agents, or actors ... Keywords: Agent-based model, Biodiversity, Biosphere Reserve, Companion modelling, Shrub encroachment, Social dynamics

Mathias Rouan; Christian Kerbiriou; Harold Levrel; Michel Etienne

2010-11-01T23:59:59.000Z

464

Modeling plankton dynamics during a Prymnesium parvum bloom: The importance of inflows and allelopathic relationships on bloom dynamics  

E-Print Network (OSTI)

Harmful algal blooms' global amplification has driven research on growth characteristics and instigating mechanisms. These blooms prosper under diverse environmental conditions, creating challenges identifying bloom initiation. The haptophyte, Prymnesium parvum, plagues the southwestern United States with massive system disruptions and huge fish kills caused by its toxin. Despite many abiotic factors' association with P. parvum blooms, low nutrient levels stress the alga increasing toxin production, eliminating nutrient competition, and alleviating grazing pressures. This model examines the relationship between nutrient availability and P. parvum toxin production against another phytoplankton and a single grazing zooplankton, using a Monod function relating population growth rate wit