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1

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/

2

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.

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

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 model redyn" 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

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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.

39

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

40

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

42

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

43

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

44

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...

45

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

46

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

47

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

48

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

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

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

57

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

58

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

59

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

60

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

62

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

63

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

64

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

65

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

66

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

67

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

68

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

69

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

70

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

71

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

72

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

73

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

74

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

75

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

76

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

77

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

78

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

79

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

80

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

82

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

83

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

84

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...

85

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

86

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

87

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

88

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

89

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

90

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

91

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

92

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

93

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

94

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

95

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

96

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

97

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

98

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

99

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

100

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

102

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

103

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

104

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

105

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

106

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

107

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

108

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

109

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

110

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

111

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

112

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

113

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

114

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

115

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

116

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

117

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

118

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

119

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

120

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

122

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

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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

132

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

133

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

134

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

135

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

136

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

137

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

138

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

139

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

140

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

Note: This page contains sample records for the topic "dynamics model redyn" from the National Library of EnergyBeta (NLEBeta).
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141

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

142

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

143

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

144

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

145

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

146

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

147

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

148

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

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

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

157

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

158

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

159

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

160

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

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

173

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

174

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

175

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.

176

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

177

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

178

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

179

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

180

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...

Note: This page contains sample records for the topic "dynamics model redyn" 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.


181

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

182

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

183

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

184

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

185

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

186

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

187

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

188

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

189

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

190

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.

191

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

192

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

193

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

194

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

195

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

196

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

197

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

198

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

199

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

200

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

202

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

203

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

204

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.

205

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

206

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

207

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

208

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

209

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

210

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

211

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

212

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

213

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

214

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

215

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

216

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...

217

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

218

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

219

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...

220

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

222

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

223

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

224

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

225

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

226

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

227

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

228

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

229

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

230

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

231

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

232

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

233

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

234

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

235

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

236

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

237

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

238

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

239

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

240

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

Note: This page contains sample records for the topic "dynamics model redyn" 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.


241

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

242

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

243

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

244

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

245

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

246

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

247

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 ...

248

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

249

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

250

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

251

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

252

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

253

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

254

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

255

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

256

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

257

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

258

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

259

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

260

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

Note: This page contains sample records for the topic "dynamics model redyn" 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.


261

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

262

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

263

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

264

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

265

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

266

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

267

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

268

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

269

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

270

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

271

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

272

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

273

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

274

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

275

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

276

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 ...

277

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

278

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

279

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

280

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

Note: This page contains sample records for the topic "dynamics model redyn" 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.


281

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

282

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

283

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

284

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

285

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

286

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

287

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

288

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

289

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

290

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

291

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

292

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

293

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

294

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

295

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

296

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

297

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

298

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

299

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

300

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

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

302

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

303

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

304

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

305

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

306

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

307

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

308

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

309

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

310

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

311

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

312

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

313

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

314

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

315

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

316

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

317

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

318

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 with limiting nutrient concentrations. Sensitivity analyses emphasize plankton biological parameters most influential in accumulating biomass. The impact of toxin production on zooplankton grazing rates underscores P. parvum's need for top-down control suppression. The toxin production equation increases production when P. parvum experiences low specific growth rates from nutrient availability and low biomass. This equation is analyzed against previously published allelopathic relationships, comparing plankton reactions and bloom endurance. The model's toxin production equation proves more ecologically feasible, incorporating competing phytoplankton species' mortality and variables easily verified through laboratory experiments. Though not intended for management strategy development, the model explores and supports the proposed strategy of incorporating hydraulic flushing, pulsed and continuous inflows, to eliminate biomass accumulation. Inflows relieve stressful nutrient-limiting conditions, introducing resources affecting bloom stability and plankton community dynamics. The faster-growing competing phytoplankton gains survival advantages when inflow rates fall lower than its maximum specific growth rate, but greater than P. Parvum's, emphasizing the accurate measuring of competitors' maximum specific growth rates and identifying a dilution rate range where P. parvum loses at nutrient intake. Inflows with various nutrient levels representing different source waters from freshwater lakes were tested for impacts on plankton dynamics. Adding any hydrological effect reduced P. parvum biomass. Disruptions create disturbance, removing P. parvum's system-dominating position, allowing the phytoplankton to exceed P. parvum's density. The model highlights the importance of P. parvum's toxin's presence to maintain dominance and emphasizes flushing agitation as potential and feasible management schemes to deter bloom continuation and increase species diversity.

Hewitt, Natalie Case

2011-05-01T23:59:59.000Z

319

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

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

Earthquake simulations help scientists understand the hazards posed by Earthquake simulations help scientists understand the hazards posed by future earthquakes. Earthquake computational models are validated by simulating well-recorded historical earthquakes and comparing simulation results to observational data. The purple border shows the extent of the 3-D structural model in the 3-D inversion. Events in red, with stations in blue. En-Jui Lee, University of Wyoming Using 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 ALCF: 150 Million Year: 2010 to 2013 Research Domain: Earth Science Researchers will use Southern California Earthquake Center (SCEC) dynamic rupture simulation software to investigate high-frequency seismic energy

320

The Role of an Advanced Land Model in Seasonal Dynamical Downscaling for Crop Model Application  

Science Conference Proceedings (OSTI)

An advanced land model [the National Center for Atmospheric Research (NCAR) Community Land Model, version 2 (CLM2)] is coupled to the Florida State University (FSU) regional spectral model to improve seasonal surface climate outlooks at very high ...

D. W. Shin; J. G. Bellow; T. E. LaRow; S. Cocke; James J. O'Brien

2006-05-01T23:59:59.000Z

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321

Wave-function entropy and dynamical-symmetry breaking in the interacting boson model  

E-Print Network (OSTI)

The degree of chaos in the Interacting Boson Model (IBM-1) is compared with what we call the "dynamical-symmetry content" of the system. The latter is represented by the information entropy of the eigenfunctions with respect to bases associated with dynamical symmetries of the IBM-1, and expresses thus the localization of actual eigenfunctions in these symmetry bases. The wave-function entropy is shown to be a sensitive tool for monitoring the processes of a single dynamical-symmetry breaking or transitions between two and more symmetries. For the IBM-1 hamiltonians studied here, the known features related to chaos, namely the dependence of chaotic measures on the hamiltonian parameters (position in the Casten triangle) and on the angular momentum, turn out to be correlated with the behaviour of the wave-function entropy. PACs 21.60.Fw; 05.45.+b

Pavel Cejnar; Jan Jolie

1998-02-25T23:59:59.000Z

322

Modeling the Dynamics of Desakota Regions: Global - Local Nexus in the Taipei Metropolitan Area  

E-Print Network (OSTI)

Since the 1970s, Asia has experienced rapid urbanization processes, which are distinct from U.S. society, and the direction of Asian urbanization is more strongly affected by economic globalization. The desakota model, proposed by McGee and Ginsburg in 1991, focuses on how internal domestic and local forces drive the specific rural-urban transformation in Asia. However, the McGee-Ginsburg model does not emphasize the importance of globalization on Asian urbanization. To fill the gap, this study develops a GIS-based CA framework based on the desakota model to not only simulate the unique urbanization processes in Asia but also integrate the influence of globalization into Asian urban dynamics. Three approaches are developed in the CA simulation: 1) physical constraints and land-use classification from remotely sensed images in 1993, 2000, and 2008, are incorporated into micro-scale transformation; 2) population dynamics, shifts of economic activities, and foreign direct investment (FDIs), a representative of the impact of globalization, are applied for multi-scale interconnection; 3) the Monte Carlo mechanism is finally introduced to combine the above two approaches and implement the simulation process. The Taipei metropolitan area, a rapid urbanizing region that highly interacts with the global economy in Asia, is chosen to examine this model. The CA simulation model establishes a strong interaction between FDIs, an indicator representing impacts of globalization, and the dazzling Asian urban model. The combination of multi-scale economic factors and micro-scale land-use transformation also reveals how urban growth of the Taipei metropolis in recent years fits the characterization of the desakota model, and how desakota regions, the growth generators, interact with city cores. As a result, the research not only successfully links the influence of globalization with the desakota model and simulates urban dynamics of Asian cities but also provides scenarios of different FDI inputs for governments to better handle urban growth with global impacts under the deep economic recession since 2007.

Wu, Bing-Sheng

2009-08-01T23:59:59.000Z

323

Control method and system for hydraulic machines employing a dynamic joint motion model  

DOE Patents (OSTI)

A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.

Danko, George (Reno, NV)

2011-11-22T23:59:59.000Z

324

Dynamical systems approach to the study of a sociophysics agent-based model  

SciTech Connect

The Sznajd model is a Potts-like model that has been studied in the context of sociophysics [1,2](where spins are interpreted as opinions). In a recent work [3], we generalized the Sznajd model to include assymetric interactions between the spins (interpreted as biases towards opinions) and used dynamical systems techniques to tackle its mean-field version, given by the flow: {eta}{sub {sigma}} = {Sigma}{sub {sigma}}'{sup M} = 1{eta}{sub {sigma}}{eta}{sigma}'({eta}{sub {sigma}}{rho}{sigma}'{yields}{sigma}-{sigma}'{rho}{sigma}{yields}{sigma}').Where hs is the proportion of agents with opinion (spin){sigma}', M is the number of opinions and {sigma}'{yields}{sigma}' is the probability weight for an agent with opinion {sigma} being convinced by another agent with opinion {sigma}'. We made Monte Carlo simulations of the model in a complex network (using Barabasi-Albert networks [4]) and they displayed the same attractors than the mean-field. Using linear stability analysis, we were able to determine the mean-field attractor structure analytically and to show that it has connections with well known graph theory problems (maximal independent sets and positive fluxes in directed graphs). Our dynamical systems approach is quite simple and can be used also in other models, like the voter model.

Timpanaro, Andre M.; Prado, Carmen P. C. [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

2011-03-24T23:59:59.000Z

325

A Dynamically Adapting Weather and Dispersion Model: The Operational Multiscale Environment Model with Grid Adaptivity (OMEGA)  

Science Conference Proceedings (OSTI)

The Operational Multiscale Environment Model with Grid Adaptivity (OMEGA) and its embedded Atmospheric Dispersion Model is a new atmospheric simulation system for real-time hazard prediction, conceived out of a need to advance the state of the ...

David P. Bacon; Nash’at N. Ahmad; Zafer Boybeyi; Thomas J. Dunn; Mary S. Hall; Pius C. S. Lee; R. Ananthakrishna Sarma; Mark D. Turner; Kenneth T. Waight III; Steve H. Young; John W. Zack

2000-07-01T23:59:59.000Z

326

On blowup dynamics in the Keller-Segel model of chemotaxis  

E-Print Network (OSTI)

We investigate the (reduced) Keller-Segel equations modeling chemotaxis of bio-organisms. We present a formal derivation and partial rigorous results of the blowup dynamics of solution of these equations describing the chemotactic aggregation of the organisms. Our results are confirmed by numerical simulations and the formula we derive coincides with the formula of Herrero and Vel\\'{a}zquez for specially constructed solutions.

S. I. Dejak; D. Egli; P. M. Lushnikov; I. M. Sigal

2013-04-04T23:59:59.000Z

327

Twisted Grosse-Wulkenhaar $\\phi^{\\star 4}$ model: dynamical noncommutativity and Noether currents  

E-Print Network (OSTI)

This paper addresses the computation of Noether currrents for the renormalizable Grosse-Wulkenhaar (GW) $\\phi^{\\star 4}$ model subjected to a dynamical noncomutativity realized through a twisted Moyal product. The noncommutative (NC) energy-momentum tensor (EMT), angular momentum tensor (AMT) and the dilatation current (DC) are explicitly derived. The breaking of translation and rotation invariances has been avoided via a constraint equation.

Hounkonnou, Mahouton Norbert

2009-01-01T23:59:59.000Z

328

A Dynamical Systems Approach Towards Modeling the Rapid Pressure Strain Correlation  

E-Print Network (OSTI)

In this study, the behavior of pressure in the Rapid Distortion Limit, along with its concomitant modeling, are addressed. In the first part of the work, the role of pressure in the initiation, propagation and suppression of flow instabilities for quadratic flows is analyzed. The paradigm of analysis considers the Reynolds stress transport equations to govern the evolution of a dynamical system, in a state space composed of the Reynolds stress tensor components. This dynamical system is scrutinized via the identification of the invariant sets and the bifurcation analysis. The changing role of pressure in quadratic flows, viz. hyperbolic, shear and elliptic, is established mathematically and the underlying physics is explained. Along the maxim of "understanding before prediction", this allows for a deeper insight into the behavior of pressure, thus aiding in its modeling. The second part of this work deals with Rapid Pressure Strain Correlation modeling in earnest. Based on the comprehension developed in the preceding section, the classical pressure strain correlation modeling approaches are revisited. Their shortcomings, along with their successes, are articulated and explained, mathematically and from the viewpoint of the governing physics. Some of the salient issues addressed include, but are not limited to, the requisite nature of the model, viz. a linear or a nonlinear structure, the success of the extant models for hyperbolic flows, their inability to capture elliptic flows and the use of RDT simulations to validate models. Through this analysis, the schism between mathematical and physical guidelines and the engineering approach, at present, is substantiated. Subsequently, a model is developed that adheres to the classical modeling framework and shows excellent agreement with the RDT simulations. The performance of this model is compared to that of other nominations prevalent in engineering simulations. The work concludes with a summary, pertinent observations and recommendations for future research in the germane field.

Mishra, Aashwin A.

2010-05-01T23:59:59.000Z

329

Development of a plant-wide dynamic model of an integrated gasification combined cycle (IGCC) plant  

Science Conference Proceedings (OSTI)

In this presentation, development of a plant-wide dynamic model of an advanced Integrated Gasification Combined Cycle (IGCC) plant with CO2 capture will be discussed. The IGCC reference plant generates 640 MWe of net power using Illinois No.6 coal as the feed. The plant includes an entrained, downflow, General Electric Energy (GEE) gasifier with a radiant syngas cooler (RSC), a two-stage water gas shift (WGS) conversion process, and two advanced 'F' class combustion turbines partially integrated with an elevated-pressure air separation unit (ASU). A subcritical steam cycle is considered for heat recovery steam generation. Syngas is selectively cleaned by a SELEXOL acid gas removal (AGR) process. Sulfur is recovered using a two-train Claus unit with tail gas recycle to the AGR. A multistage intercooled compressor is used for compressing CO2 to the pressure required for sequestration. Using Illinois No.6 coal, the reference plant generates 640 MWe of net power. The plant-wide steady-state and dynamic IGCC simulations have been generated using the Aspen Plus{reg_sign} and Aspen Plus Dynamics{reg_sign} process simulators, respectively. The model is generated based on the Case 2 IGCC configuration detailed in the study available in the NETL website1. The GEE gasifier is represented with a restricted equilibrium reactor model where the temperature approach to equilibrium for individual reactions can be modified based on the experimental data. In this radiant-only configuration, the syngas from the Radiant Syngas Cooler (RSC) is quenched in a scrubber. The blackwater from the scrubber bottom is further cleaned in the blackwater treatment plant. The cleaned water is returned back to the scrubber and also used for slurry preparation. The acid gas from the sour water stripper (SWS) is sent to the Claus plant. The syngas from the scrubber passes through a sour shift process. The WGS reactors are modeled as adiabatic plug flow reactors with rigorous kinetics based on the mid-life activity of the shift-catalyst. The SELEXOL unit consists of the H2S and CO2 absorbers that are designed to meet the stringent environmental limits and requirements of other associated units. The model also considers the stripper for recovering H2S that is sent as a feed to a split-flow Claus unit. The tail gas from the Claus unit is recycled to the SELEXOL unit. The cleaned syngas is sent to the GE 7FB gas turbine. This turbine is modeled as per published data in the literature. Diluent N2 is used from the elevated-pressure ASU for reducing the NOx formation. The heat recovery steam generator (HRSG) is modeled by considering generation of high-pressure, intermediate-pressure, and low-pressure steam. All of the vessels, reactors, heat exchangers, and the columns have been sized. The basic IGCC process control structure has been synthesized by standard guidelines and existing practices. The steady-state simulation is solved in sequential-modular mode in Aspen Plus{reg_sign} and consists of more than 300 unit operations, 33 design specs, and 16 calculator blocks. The equation-oriented dynamic simulation consists of more than 100,000 equations solved using a multi-step Gear's integrator in Aspen Plus Dynamics{reg_sign}. The challenges faced in solving the dynamic model and key transient results from this dynamic model will also be discussed.

Bhattacharyya, D.; Turton, R.; Zitney, S.

2009-01-01T23:59:59.000Z

330

A particle numerical model for wall film dynamics in port-injected engines  

DOE Green Energy (OSTI)

To help predict hydrocarbon emissions during cold-start conditions the authors are developing a numerical model for the dynamics and vaporization of the liquid wall films formed in port-injected spark-ignition engines and incorporating this model in the KIVA-3 code for complex geometries. This paper summarizes the current status of the project and presents illustrative example calculations. The dynamics of the wall film is influenced by interactions with the impinging spray, the wall, and the gas flow near the wall. The spray influences the film through mass, tangential momentum, and energy addition. The wall affects the film through the no-slip boundary condition and heat transfer. The gas alters film dynamics through tangential stresses and heat and mass transfer in the gas boundary layers above the films. New wall functions are given to predict transport in the boundary layers above the vaporizing films. It is assumed the films are sufficiently thin that film flow is laminar and that liquid inertial forces are negligible. Because liquid Prandtl numbers are typically about then, unsteady heating of the film should be important and is accounted for by the model. The thin film approximation breaks down near sharp corners, where an inertial separation criterion is used. A particle numerical method is used for the wall film. This has the advantages of compatibility with the KIVA-3 spray model and of very accurate calculation of convective transport of the film. The authors have incorporated the wall film model into KIVA-3, and the resulting combined model can be used to simulate the coupled port and cylinder flows in modern spark-ignition engines. They give examples by comparing computed fuel distributions with closed- and open-valve injection during the intake and compression strokes of a generic two-valve engine.

O`Rourke, P.J.; Amsden, A.A.

1996-09-01T23:59:59.000Z

331

Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status  

Science Conference Proceedings (OSTI)

The Advanced High-Temperature Reactor (AHTR) is a large-output fluoride-salt-cooled high-temperature reactor (FHR). An early-phase preconceptual design of a 1500 MW(e) power plant was developed in 2011 [Refs. 1 and 2]. An updated version of this plant is shown as Fig. 1. FHRs feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR is designed to be a “walk away” reactor that requires no action to prevent large off-site releases following even severe reactor accidents. This report describes the development of dynamic system models used to further the AHTR design toward that goal. These models predict system response during warmup, startup, normal operation, and limited off-normal operating conditions. Severe accidents that include a loss-of-fluid inventory are not currently modeled. The scope of the models is limited to the plant power system, including the reactor, the primary and intermediate heat transport systems, the power conversion system, and safety-related or auxiliary heat removal systems. The primary coolant system, the intermediate heat transport system and the reactor building structure surrounding them are shown in Fig. 2. These systems are modeled in the most detail because the passive interaction of the primary system with the surrounding structure and heat removal systems, and ultimately the environment, protects the reactor fuel and the vessel from damage during severe reactor transients. The reactor silo also plays an important role during system warmup. The dynamic system modeling tools predict system performance and response. The goal is to accurately predict temperatures and pressures within the primary, intermediate, and power conversion systems and to study the impacts of design changes on those responses. The models are design tools and are not intended to be used in reactor qualification. The important details to capture in the primary system relate to flows within the reactor vessel during severe events and the resulting temperature profiles (temperature and duration) for major components. Critical components include the fuel, reactor vessel, primary piping, and the primary-to-intermediate heat exchangers (P-IHXs). The major AHTR power system loops are shown in Fig. 3. The intermediate heat transfer system is a group of three pumped salt loops that transports the energy produced in the primary system to the power conversion system. Two dynamic system models are used to analyze the AHTR. A Matlab/Simulink?-based model initiated in 2011 has been updated to reflect the evolving design parameters related to the heat flows associated with the reactor vessel. The Matlab model utilizes simplified flow assumptions within the vessel and incorporates an empirical representation of the Direct Reactor Auxiliary Cooling System (DRACS). A Dymola/Modelica? model incorporates a more sophisticated representation of primary coolant flow and a physics-based representation of the three-loop DRACS thermal hydraulics. This model is not currently operating in a fully integrated mode. The Matlab model serves as a prototype and provides verification for the Dymola model, and its use will be phased out as the Dymola model nears completion. The heat exchangers in the system are sized using spreadsheet-based, steady-state calculations. The detail features of the heat exchangers are programmed into the dynamic models, and the overall dimensions are used to generate realistic plant designs. For the modeling cases where the emphasis is on understanding responses within the intermediate and primary systems, the power conversion system may be modeled as a simple boundary condition at the intermediate-to-power conversion system heat exchangers.

Qualls, A.L.; Cetiner, M.S.; Wilson, T.L., Jr.

2012-04-30T23:59:59.000Z

332

Equilibrium Response and Transient Dynamics Datasets from VEMAP, the Vegetation/Ecosystem Modeling and Analysis Project  

DOE Data Explorer (OSTI)

Users of the VEMAP Portal can access input files of numerical data that include monthly and daily files of geographic data, soil and site files, scenario files, etc. Model results from Phase I, the Equilibrium Response datasets, are available through the NCAR anonymous FTP site at http://www.cgd.ucar.edu/vemap/vresults.html. Phase II, Transient Dynamics, include climate datasets, models results, and analysis tools. Many supplemental files are also available from the main data page at http://www.cgd.ucar.edu/vemap/datasets.html.

333

Stochastic dynamics of small ensembles of non-processive molecular motors: the parallel cluster model  

E-Print Network (OSTI)

Non-processive molecular motors have to work together in ensembles in order to generate appreciable levels of force or movement. In skeletal muscle, for example, hundreds of myosin II molecules cooperate in thick filaments. In non-muscle cells, by contrast, small groups with few tens of non-muscle myosin II motors contribute to essential cellular processes such as transport, shape changes or mechanosensing. Here we introduce a detailed and analytically tractable model for this important situation. Using a three-state crossbridge model for the myosin II motor cycle and exploiting the assumptions of fast power stroke kinetics and equal load sharing between motors in equivalent states, we reduce the stochastic reaction network to a one-step master equation for the binding and unbinding dynamics (parallel cluster model) and derive the rules for ensemble movement. We find that for constant external load, ensemble dynamics is strongly shaped by the catch bond character of myosin II, which leads to an increase of the fraction of bound motors under load and thus to firm attachment even for small ensembles. This adaptation to load results in a concave force-velocity relation described by a Hill relation. For external load provided by a linear spring, myosin II ensembles dynamically adjust themselves towards an isometric state with constant average position and load. The dynamics of the ensembles is now determined mainly by the distribution of motors over the different kinds of bound states. For increasing stiffness of the external spring, there is a sharp transition beyond which myosin II can no longer perform the power stroke. Slow unbinding from the pre-power-stroke state protects the ensembles against detachment.

Thorsten Erdmann; Philipp J. Albert; Ulrich S. Schwarz

2013-07-24T23:59:59.000Z

334

ON THE DYNAMICS OF THE SOLAR CORONA: FIRST RESULTS OBTAINED WITH A NEW 3D MHD MODEL  

E-Print Network (OSTI)

; CWENO. 1. MOTIVATION For many decades space scientists have been at- tracted to the solar wind and its1 ON THE DYNAMICS OF THE SOLAR CORONA: FIRST RESULTS OBTAINED WITH A NEW 3D MHD MODEL J. Kleimann 1) is applied to the problem of the dynamics of the solar corona. First, we present the basic system

Grauer, Rainer

335

A model reduction approach for constructing compact dynamic thermal models of IGBT-modules of inverters  

Science Conference Proceedings (OSTI)

This paper presents a model reduction approach for constructing lumped RC thermal networks of IGBT-modules of inverters for which heat and subsequent temperature increases vary with time on different scales ranging from nanosecond to second. It was observed ... Keywords: Compact thermal modelling, Electro-thermal simulation, IGBT-modules, Inverters, Thermal analysis

J. Antonios; N. Ginot; C. Batard; Y. Scudeller; M. Machmoum

2012-06-01T23:59:59.000Z

336

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

337

DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE  

E-Print Network (OSTI)

This work presents a modeling and control study of a reactive distillation column used for hydrogenation of benzene. A steady state and a dynamic model have been developed to investigate control structures for the column. The most important aspects of this control problem are that the purity of the product streams regarding benzene need to be met. At the same time as little toluene as possible should be converted. The former is a constraint imposed by EPA regulations while the latter is tied to process economics due to the high octane number of toluene. It is required to satisfy both of these objectives even under the influence of disturbances, as the feed composition changes on a regular basis. The dynamic model is used for developing transfer function models of two potential control structures. Pairing of inputs and outputs is performed based upon the Relative Gain Array (RGA) and PI controllers were designed for each control structure. The controller performance was then compared in simulation studies. From our results, control structure 2 performed better than control structure 1. The main advantage of CS2 over CS1 is noticed in the simulation of feed composition disturbance rejection, where CS2 returns all variables back to steady state within 3 hrs while it take CS1 more than 20 hrs to return the temperature variables back to steady state.

Aluko, Obanifemi

2008-08-01T23:59:59.000Z

338

Full vehicle dynamics model of a formula SAE racecar using ADAMS/Car  

E-Print Network (OSTI)

The Texas A&M University Formula SAE program currently has no rigorous method for analyzing or predicting the overall dynamic behavior of the student-designed racecars. The objective of this study is to fulfill this need by creating a full vehicle ADAMS/Car model incorporating an empirical tire-road force model and validating the longitudinal performance of the model by using vehicle responses recorded at the track. Creating the model requires measuring mass and inertia properties for each part, measuring the locations of all the kinematic joints, testing the Risse Racing Jupiter-5 shocks to characterize damping and stiffness, measuring engine torque, and modeling the tire behavior. Measuring the vehicle performance requires installation of the Pi Research DataBuddy data acquisition system and appropriate sensors. The 2002 Texas A&M University Formula SAE racecar, the subject vehicle, was selected because it already included some accommodations for sensors and is almost identical in layout to the available ADAMS/Car model Formula SAE templates. The tire-road interface is described by the Pacejka ??94 handling force model within ADAMS/Car that is based on a set of Goodyear coefficients. The majority of the error in the model originated from the Goodyear tire model and the 2004 engine torque map. The testing used Hoosier tires and the 2002 engine intake and exhaust configuration. The deliverable is a full vehicle model of the 2002 racecar with a 2004 engine torque map and a tire model correlated to longitudinal performance recorded at the track using the installed data acquisition system. The results of the correlation process, confirmed by driver impressions and performance of the 2004 racecar, show that the 2004 engine torque map predicts higher performance than the measured response with the 2002 engine. The Hoosier tire on the Texas A&M University Riverside Campus track surface produces 75??3% of peak longitudinal tire performance predicted by the Goodyear tire model combined with a road surface friction coefficient of 1.0. The ADAMS/Car model can now support the design process as an analysis tool for full vehicle dynamics and with continued refinement, will be able to accurately predict behavior throughout a complete autocross course.

Mueller, Russell Lee

2005-08-01T23:59:59.000Z

339

Langevin model for real-time Brownian dynamics of interacting nanodefects in irradiated metals  

SciTech Connect

In situ real-time electron microscope observations of metals irradiated with ultrahigh-energy electrons or energetic ions show that the dynamics of microstructural evolution in these materials is strongly influenced by long-range elastic interactions between mobile nanoscale radiation defects. Treating long-range interactions is also necessary for modeling microstructures formed in ex situ high-dose-rate ion-beam irradiation experiments, and for interpolating the ion-beam irradiation data to the low-dose-rate limit characterizing the neutron irradiation environments of fission or fusion power plants. We show that simulations, performed using an algorithm where nanoscale radiation defects are treated as interacting Langevin particles, are able to match and explain the real-time dynamics of nanodefects observed in in situ electron microscope experiments.

Dudarev, S. L. [EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Gilbert, M. R. [EURATOM/CCFE Fusion Association, Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Arakawa, K. [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Okinawa Institute of Science and Technology, Kunigami, Okinawa 904-0411 (Japan); CREST, JST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Mori, H. [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yao, Z. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Department of Mechanical and Materials Engineering, Queen's University, Nicol Hall, 60 Union Street, Kingston, Ontario, K7L 3N6 (Canada); Jenkins, M. L. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Derlet, P. M. [Condensed Matter Theory Group, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2010-06-01T23:59:59.000Z

340

The ArcSDE GIS Dynamic Population Model Tool for Savannah River Site Emergency Response  

Science Conference Proceedings (OSTI)

The Savannah River Site (SRS) is a 310-square-mile Department of Energy site located near Aiken, South Carolina. With a workforce of over 10,000 employees and subcontractors, SRS emergency personnel must be able to respond to an emergency event in a timely and effective manner, in order to ensure the safety and security of the Site. Geographic Information Systems (GIS) provides the technology needed to give managers and emergency personnel the information they need to make quick and effective decisions. In the event of a site evacuation, knowing the number of on-site personnel to evacuate from a given area is an essential piece of information for emergency staff. SRS has developed a GIS Dynamic Population Model Tool to quickly communicate real-time information that summarizes employee populations by facility area and building and then generates dynamic maps that illustrate output statistics.

MCLANE, TRACY; JONES, DWIGHT

2005-10-03T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

SciTech Connect

Mathematical modeling of ice sheets is complicated by the non-linearity of the governing equations and boundary conditions. Standard grid-based methods require complex front tracking techniques and have limited capability to handle large material deformations and abrupt changes in bottom topography. As a consequence, numerical methods are usually restricted to shallow ice sheet and ice shelf approximations. We propose a new smoothed particle hydrodynamics (SPH) non-Newtonian model for coupled ice sheet and ice shelf dynamics. SPH, a fully Lagrangian particle method, is highly scalable and its Lagrangian nature and meshless discretization are well suited to the simulation of free surface ?ows, large material deformation, and material fragmentation. In this paper, SPH is used to study 3D ice sheet/ice shelf behavior, and the dynamics of the grounding line. The steady state position of the grounding line obtained from SPH simulations is in good agreement with laboratory observations for a wide range of simulated bedrock slopes, and density ratios, similar to those of ice and sea water. The numerical accuracy of the SPH algorithm is veri?ed by simulating Poiseuille ?ow, plane shear ?ow with free surface and the propagation of a blob of ice along a horizontal surface. In the laboratory experiment, the ice was represented with a viscous Newtonian ?uid. In the present work, however, the ice is modeled as both viscous Newtonian ?uid and non-Newtonian ?uid, such that the e?ect of non-Newtonian rheology on the dynamics of grounding line was examined. The non-Newtonian constitutive relation is prescribed to be Glen’s law for the creep of polycrystalline ice. A V-shaped bedrock ramp is further introduced to model the real geometry of bedrock slope.

Pan, Wenxiao; Tartakovsky, Alexandre M.; Monaghan, Joseph J.

2013-06-01T23:59:59.000Z

342

A Three-Dimensional Numerical Model of an Isolated Thunderstorm. Part II: Dynamics of Updraft Splitting and Mesovortex Couplet Evolution  

Science Conference Proceedings (OSTI)

This study analyzes the dynamics of an isolated convective storm embedded within marked ambient vertical wind shear dominated by low-level veering, as simulated by a three-dimensional anelastic numerical modeling experiment. Two particular ...

Robert E. Schlesinger

1980-02-01T23:59:59.000Z

343

The Mid-Quaternary Climatic Transition as the Free Response of a Three-Variable Dynamical Model  

Science Conference Proceedings (OSTI)

A simplified version of a previously described dynamical model governing global ice mass, atmospheric carbon dioxide, and mean ocean temperature (that may also be a proxy for some other CO2–controlling oceanic variable, e.g., nutrient supply) is ...

Barry Saltzman; Alfonso Sutera

1987-01-01T23:59:59.000Z

344

Dynamic Assimilation of MODIS-Retrieved Humidity Profiles within a Regional Model for High-Latitude Forecast Applications  

Science Conference Proceedings (OSTI)

A “hot start” technique is applied to the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) to dynamically assimilate cloud properties and humidity profiles retrieved from the ...

Xingang Fan; Jeffrey S. Tilley

2005-12-01T23:59:59.000Z

345

The Dynamics of Error Growth and Predictability in a Model of the Gulf Stream. Part I: Singular Vector Analysis  

Science Conference Proceedings (OSTI)

The recently developed ideas of generalized linear stability theory for dynamical systems are applied to time evolving flows of the Gulf Stream using a quasigeostrophic numerical model. The potential for the growth of perturbations arising from ...

Andrew M. Moore; Arthur J. Mariano

1999-02-01T23:59:59.000Z

346

The use of a distributed hydrologic model to predict dynamic landslide susceptibility for a humid basin in Puerto Rico  

E-Print Network (OSTI)

This thesis describes the use of a distributed hydrology model in conjunction with a Factor of Safety (FS) algorithm to predict dynamic landslide susceptibility for a humid basin in Puerto Rico. The Mameyes basin, located ...

Kamal, Sameer A. (Sameer Ahmed)

2009-01-01T23:59:59.000Z

347

A Model of the Near-Surface Circulation of the Santa Barbara Channel: Comparison with Observations and Dynamical Interpretations  

Science Conference Proceedings (OSTI)

Previous studies indicate the importance of wind, wind curl, and density differences in driving the near-surface circulation in the Santa Barbara Channel (SBC). Here model sensitivity experiments and dynamical analyses of the near-surface ...

Lie-Yauw Oey; Clinton Winant; Ed Dever; Walter R. Johnson; Dong-Ping Wang

2004-01-01T23:59:59.000Z

348

Cray T3E Performances of a Parallel Code for a Stochastic Dynamic Assets and Liabilities Management Model  

Science Conference Proceedings (OSTI)

A parallel Asset & Liability Management (ALM) code was developed by SMART and Prometeia Calcolo for the EC project PALMA (Parallel Asset and Liability MAnagement). The code implements a stochastic approach based on a dynamic ALM model specially tailored ...

G. Zanghirati; F. Cocco; F. Taddei; G. Paruolo

1999-08-01T23:59:59.000Z

349

Detailed Simulations of Atmospheric Flow and Dispersion in Downtown Manhattan: An Application of Five Computational Fluid Dynamics Models  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) model simulations of urban boundary layers have improved in speed and accuracy so that they are useful in assisting in planning emergency response activities related to releases of chemical or biological agents ...

Steven R. Hanna; Michael J. Brown; Fernando E. Camelli; Stevens T. Chan; William J. Coirier; Sura Kim; Olav R. Hansen; Alan H. Huber; R. Michael Reynolds

2006-12-01T23:59:59.000Z

350

A Detailed Microphysical Model Within a Two-Dimensional Dynamic Framework: Model Description and Preliminary Results  

Science Conference Proceedings (OSTI)

A two-dimensional anelastic cloud model which incorporates detailed treatments of the water and ice phase is presented. The liquid phase processes considered include condensation, quasi-stochastic coalescence, fallout and breakup, while the ice ...

William D. Hall

1980-11-01T23:59:59.000Z

351

Model updating of a dynamic system in a high-temperature environment based on a hierarchical method  

Science Conference Proceedings (OSTI)

In the past, structural model updating methods have been widely researched as a means to reconcile mathematical models because the key parameters in dynamic systems often change during their life cycle due to repair and replacement of parts or the environment. ... Keywords: Analysis variance, FE model updating, Genetic algorithm, Hierarchical, High temperature, RBF predictor

He Cheng, Chen Guoping, He Huan, Sun Rujie

2013-12-01T23:59:59.000Z

352

The Ocean–Land–Atmosphere Model (OLAM). Part II: Formulation and Tests of the Nonhydrostatic Dynamic Core  

Science Conference Proceedings (OSTI)

The dynamic core of the Ocean–Land–Atmosphere Model (OLAM), which is a new global model that is partly based on the Regional Atmospheric Modeling System (RAMS), is described and tested. OLAM adopts many features of its predecessor, but its ...

Robert L. Walko; Roni Avissar

2008-11-01T23:59:59.000Z

353

Large scale dynamics of the Persistent Turning Walker model of fish behavior  

E-Print Network (OSTI)

This paper considers a new model of individual displacement, based on fish motion, the so-called Persistent Turning Walker (PTW) model, which involves an Ornstein-Uhlenbeck process on the curvature of the particle trajectory. The goal is to show that its large time and space scale dynamics is of diffusive type, and to provide an analytic expression of the diffusion coefficient. Two methods are investigated. In the first one, we compute the large time asymptotics of the variance of the individual stochastic trajectories. The second method is based on a diffusion approximation of the kinetic formulation of these stochastic trajectories. The kinetic model is a Fokker-Planck type equation posed in an extended phase-space involving the curvature among the kinetic variables. We show that both methods lead to the same value of the diffusion constant. We present some numerical simulations to illustrate the theoretical results.

Pierre Degond; Sébastien Motsch

2007-10-26T23:59:59.000Z

354

Effects of f(R) Model on the Dynamical Instability of Expansionfree Gravitational Collapse  

E-Print Network (OSTI)

Dark energy models based on f(R) theory have been extensively studied in literature to realize the late time acceleration. In this paper, we have chosen a viable f(R) model and discussed its effects on the dynamical instability of expansionfree fluid evolution generating a central vacuum cavity. For this purpose, contracted Bianchi identities are obtained for both the usual matter as well as dark source. The term dark source is named to the higher order curvature corrections arising from f(R) gravity. The perturbation scheme is applied and different terms belonging to Newtonian and post Newtonian regimes are identified. It is found that instability range of expansionfree fluid on external boundary as well as on internal vacuum cavity is independent of adiabatic index $\\Gamma$ but depends upon the density profile, pressure anisotropy and f(R) model.

M. Sharif; H. Rizwana Kausar

2011-09-14T23:59:59.000Z

355

A Smoothed Particle Hydrodynamics Model for Ice Sheet and Ice Shelf Dynamics  

SciTech Connect

Mathematical modeling of ice sheets is complicated by the non-linearity of the governing equations and boundary conditions. Standard grid-based methods require complex front tracking techniques and have limited capability to handle large material deformations and abrupt changes in bottom topography. As a consequence, numerical methods are usually restricted to shallow ice sheet and ice shelf approximations. We propose a new smoothed particle hydrodynamics (SPH) model for coupled ice sheet and ice shelf dynamics. SPH is a fully Lagrangian particle method. It is highly scalable and its Lagrangian nature and meshless discretization are well suited to the simulation of free surface flows, large material deformation, and material fragmentation. In this paper SPH is used to study ice sheet/ice shelf behavior, and the dynamics of the grounding line. The steady state position of the grounding line obtained from the SPH simulations is in good agreement with laboratory observations for a wide range of simulated bedrock slopes, and density ratios similar to those of ice and sea water. The numerical accuracy of the SPH algorithm is further verified by simulating the plane shear flow of two immiscible fluids and the propagation of a highly viscous blob of fluid along a horizontal surface. In the experiment, the ice was represented with a viscous newtonian fluid. For consistency, in the described SPH model the ice is also modeled as a viscous newtonian fluid. Typically, ice sheets are modeled as a non-Newtonian fluid, accounting for the changes in the mechanical properties of ice. Implementation of a non-Newtonian rheology in the SPH model is the subject of our ongoing research.

Pan, Wenxiao; Tartakovsky, Alexandre M.; Monaghan, Joseph J.

2012-02-08T23:59:59.000Z

356

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

357

Documentation of INL’s In Situ Oil Shale Retorting Water Usage System Dynamics Model  

SciTech Connect

A system dynamic model was construction to evaluate the water balance for in-situ oil shale conversion. The model is based on a systems dynamics approach and uses the Powersim Studio 9™ software package. Three phases of an in situ retort were consider; a construction phase primarily accounts for water needed for drilling and water produced during dewatering, an operation phase includes the production of water from the retorting process, and a remediation phase water to remove heat and solutes from the subsurface as well as return the ground surface to its natural state. Throughout these three phases, the water is consumed and produced. Consumption is account for through the drill process, dust control, returning the ground water to its initial level and make up water losses during the remedial flushing of the retort zone. Production of water is through the dewatering of the retort zone, and during chemical pyrolysis reaction of the kerogen conversion. The document discusses each of the three phases used in the model.

Earl D Mattson; Larry Hull

2012-12-01T23:59:59.000Z

358

Use of a dynamic simulation model to understand nitrogen cycling in the middle Rio Grande, NM.  

Science Conference Proceedings (OSTI)

Water quality often limits the potential uses of scarce water resources in semiarid and arid regions. To best manage water quality one must understand the sources and sinks of both solutes and water to the river system. Nutrient concentration patterns can identify source and sink locations, but cannot always determine biotic processes that affect nutrient concentrations. Modeling tools can provide insight into these large-scale processes. To address questions about large-scale nitrogen removal in the Middle Rio Grande, NM, we created a system dynamics nitrate model using an existing integrated surface water--groundwater model of the region to evaluate our conceptual models of uptake and denitrification as potential nitrate removal mechanisms. We modeled denitrification in groundwater as a first-order process dependent only on concentration and used a 5% denitrification rate. Uptake was assumed to be proportional to transpiration and was modeled as a percentage of the evapotranspiration calculated within the model multiplied by the nitrate concentration in the water being transpired. We modeled riparian uptake as 90% and agricultural uptake as 50% of the respective evapotranspiration rates. Using these removal rates, our model results suggest that riparian uptake, agricultural uptake and denitrification in groundwater are all needed to produce the observed nitrate concentrations in the groundwater, conveyance channels, and river as well as the seasonal concentration patterns. The model results indicate that a total of 497 metric tons of nitrate-N are removed from the Middle Rio Grande annually. Where river nitrate concentrations are low and there are no large nitrate sources, nitrate behaves nearly conservatively and riparian and agricultural uptake are the most important removal mechanisms. Downstream of a large wastewater nitrate source, denitrification and agricultural uptake were responsible for approximately 90% of the nitrogen removal.

Meixner, Tom (University of Arizona, Tucson, AZ); Tidwell, Vincent Carroll; Oelsner, Gretchen (University of Arizona, Tucson, AZ); Brooks, Paul (University of Arizona, Tucson, AZ); Roach, Jesse D.

2008-08-01T23:59:59.000Z

359

Examining Uncertainty in Demand Response Baseline Models and Variability in Automated Response to Dynamic Pricing  

Science Conference Proceedings (OSTI)

Controlling electric loads to deliver power system services presents a number of interesting challenges. For example, changes in electricity consumption of Commercial and Industrial (C&I) facilities are usually estimated using counterfactual baseline models, and model uncertainty makes it difficult to precisely quantify control responsiveness. Moreover, C&I facilities exhibit variability in their response. This paper seeks to understand baseline model error and demand-side variability in responses to open-loop control signals (i.e. dynamic prices). Using a regression-based baseline model, we define several Demand Response (DR) parameters, which characterize changes in electricity use on DR days, and then present a method for computing the error associated with DR parameter estimates. In addition to analyzing the magnitude of DR parameter error, we develop a metric to determine how much observed DR parameter variability is attributable to real event-to-event variability versus simply baseline model error. Using data from 38 C&I facilities that participated in an automated DR program in California, we find that DR parameter errors are large. For most facilities, observed DR parameter variability is likely explained by baseline model error, not real DR parameter variability; however, a number of facilities exhibit real DR parameter variability. In some cases, the aggregate population of C&I facilities exhibits real DR parameter variability, resulting in implications for the system operator with respect to both resource planning and system stability.

Mathieu, Johanna L.; Callaway, Duncan S.; Kiliccote, Sila

2011-08-15T23:59:59.000Z

360

Simulating soil C dynamics with EPIC: Model description and testing against long-term data  

SciTech Connect

Soil carbon sequestration (SCS) has emerged as a technology with significant potential to help stabilize atmospheric CO2 concentrations and thus reduce the threat of global warming. Methods and models are needed to evaluate and recommend SCS practices based on their effects on carbon dynamics and environmental quality. EPIC (Environment Policy Integrated Climate) is a widely used and tested model for simulating many agroecosystem processes including plant growth, crop yield, tillage, wind and water erosion, runoff, soil density, and leaching. Here we describe new C and N modules developed in EPIC built on concepts from the Century model to connect the simulation of soil C dynamics to crop management, tillage methods, and erosion processes. The added C and N routines interact directly with soil moisture, temperature, erosion, tillage, soil density, leaching, and translocation functions in EPIC. Equations were also added to describe the effects of soil texture on soil C stabilization. Lignin concentration is modeled as a sigmoidal function of plant age. EPIC was tested against data from a Conservation Reserve Program (CRP) 6-yr experiment at five sites in three U.S. Great Plains states and a 61-y long-term agronomic experiment in Canada. Mean Square Deviations (MSD) calculated for CRP sites were less than 0.01 kg C2 m2, except for one site where it reached 0.025 kg2 C2 m. MSD values in the 61-y experiment ranged between 0.047 and 0.077 kg C2 m2. In conclusion, the version of the EPIC model presented and tested here contains the necessary algorithms to simulate SCS and improve understanding of the interactions among soil erosion, C dynamics, and tillage. A strength of the model as tested is its ability to explain the variability in crop production, C inputs and SOC and N cycling over a wised range soil, cropping and climatic conditions over periods from 6 to 61 years. For example, at the Breton site over 61 years, EPIC accounted for 69% of the variability in grain yields, 89 % of the variability in C inputs and 91 % of the variability in SOC content in the top 15 cm. Continued development is be needed is in understanding why it overpredicts at low SOC and underpredicts at high SOC. Possibilities now exit to connect the C and N cycling parts of EPIC to algorithms to describe denitrification as driven by C metabolism and oxygen availability.

Izaurralde, R Cesar C.; Williams, Jimmy R.; Mcgill, William B.; Rosenberg, Norman J.; Quiroga Jakas, Maria C.

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics model redyn" 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

A Dynamic Two-Phase Flow Model of Proton Exchange Membrane Fuel Cells  

E-Print Network (OSTI)

A dynamic two phase flow model for proton exchange membrane (PEM) fuel cells is presented. The two dimensional along-the-channel model includes the two phase flow of water (gaseous and liquid) in the porous diffusion layers and in the catalyst layers, as well as the transport of the species in the gas phase. Moreover, proton and water transport in the membrane and the oxygen reduction reaction in the cathodic catalyst layer is accounted for. The discretisation of the resulting flow equations is done by a mixed finite element approach. Based on this the transport equations for the species in each phase are discretised by a finite volume scheme. The coupled mixed finite element/finite volume approach gives the spatially resolved water and gas saturation and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations for the electrons and protons are solved by using Galerkin finite element schemes.

Karsten Kühn; K. Kühn; Mario Ohlberger; Jürgen O. Schumacher; C. Ziegler; R. Klöfkorn; Karsten Kühn Ab; Mario Ohlberger Cd; Jürgen O. Schumacher A; Christoph Ziegler; Robert Klöfkorn C

2003-01-01T23:59:59.000Z

362

Dynamics of Quintessence Models of Dark Energy with Exponential Coupling to the Dark Matter  

E-Print Network (OSTI)

We explore quintessence models of dark energy which exhibit non-minimal coupling between the dark matter and the dark energy components of the cosmic fluid. The kind of coupling chosen is inspired in scalar-tensor theories of gravity. We impose a suitable dynamics of the expansion allowing to derive exact Friedmann-Robertson-Walker solutions once the coupling function is given as input. Self-interaction potentials of single and double exponential types emerge as result of our choice of the coupling function. The stability and existence of the solutions is discussed in some detail. Although, in general, models with appropriated interaction between the components of the cosmic mixture are useful to handle the coincidence problem, in the present study the coincidence can not be evaded due to the choice of the solution generating ansatz.

Tame Gonzalez; Genly Leon; Israel Quiros

2007-02-08T23:59:59.000Z

363

Radial electric field 3D modeling for wire arrays driving dynamic hohlraums on Z.  

SciTech Connect

The anode-cathode structure of the Z-machine wire array results in a higher negative radial electric field (Er) on the wires near the cathode relative to the anode. The magnitude of this field has been shown to anti-correlate with the axial radiation top/bottom symmetry in the DH (Dynamic Hohlraum). Using 3D modeling, the structure of this field is revealed for different wire-array configurations and for progressive mechanical alterations, providing insight for minimizing the negative Er on the wire array in the anode-to-cathode region of the DH. Also, the 3D model is compared to Sasorov's approximation, which describes Er at the surface of the wire in terms of wire-array parameters.

Mock, Raymond Cecil

2007-06-01T23:59:59.000Z

364

$?^{*}N?$ Form Factors from a Relativistic Dynamical Model of Pion Electroproduction  

E-Print Network (OSTI)

We obtain the electromagnetic form factors of the $\\gamma N\\Delta$ transition by analyzing recent pion-electroproduction data using a fully relativistic dynamical model. Special care is taken to satisfy Ward-Takahashi identities for the Born term in the presence of form factors thereby allowing the use of realistic electromagnetic form factors of the nucleon and pion. We parametrize the $Q^2$ dependence of the {\\it bare} $\\gamma N \\Delta$ form factors by a three-parameter form which is consistent with the asymptotic behavior inferred from QCD. The parameters of the bare $\\gamma N \\Delta$ form factors are the only free parameters of the model and are fitted to the differential cross-section and multipole-analysis data up to $Q^2=4$ (GeV/c)$^2$ in the $\\Delta(1232)$-resonance region. This analysis emphasizes the significance of the pion-cloud effects in the extraction of the resonance parameters.

G. L. Caia; V. Pascalutsa; J. A. Tjon; L. E. Wright

2004-07-21T23:59:59.000Z

365

Water Usage for In-Situ Oil Shale Retorting – A Systems Dynamics Model  

SciTech Connect

A system dynamic model was construction to evaluate the water balance for in-situ oil shale conversion. The model is based on a systems dynamics approach and uses the Powersim Studio 9™ software package. Three phases of an insitu retort were consider; a construction phase primarily accounts for water needed for drilling and water produced during dewatering, an operation phase includes the production of water from the retorting process, and a remediation phase water to remove heat and solutes from the subsurface as well as return the ground surface to its natural state. Throughout these three phases, the water is consumed and produced. Consumption is account for through the drill process, dust control, returning the ground water to its initial level and make up water losses during the remedial flushing of the retort zone. Production of water is through the dewatering of the retort zone, and during chemical pyrolysis reaction of the kerogen conversion. The major water consumption was during the remediation of the insitu retorting zone.

Earl D. Mattson; Larry Hull; Kara Cafferty

2012-12-01T23:59:59.000Z

366

Three-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Electrolysis Cells and Stacks  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created for detailed analysis of a high-temperature electrolysis stack (solid oxide fuel cells operated as electrolyzers). Inlet and outlet plenum flow distributions are discussed. Maldistribution of plena flow show deviations in per-cell operating conditions due to non-uniformity of species concentrations. Models have also been created to simulate experimental conditions and for code validation. Comparisons between model predictions and experimental results are discussed. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the electrolysis mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Variations in flow distribution, and species concentration are discussed. End effects of flow and per-cell voltage are also considered. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition.

Grant Hawkes; James O'Brien; Carl Stoots; Stephen Herring

2008-07-01T23:59:59.000Z

367

Projecting Low Dimensional Chaos from Spatio-temporal Dynamics in a Model for Plastic Instability  

E-Print Network (OSTI)

We investigate the possibility of projecting low dimensional chaos from spatiotemporal dynamics of a model for a kind of plastic instability observed under constant strain rate deformation conditions. We first discuss the relationship between the spatiotemporal patterns of the model reflected in the nature of dislocation bands and the nature of stress serrations. We show that at low applied strain rates, there is a one-to-one correspondence with the randomly nucleated isolated bursts of mobile dislocation density and the stress drops. We then show that the model equations are spatiotemporally chaotic by demonstrating the number of positive Lyapunov exponents and Lyapunov dimension scale with the system size at low and high strain rates. Using a modified algorithm for calculating correlation dimension density, we show that the stress-strain signals at low applied strain rates corresponding to spatially uncorrelated dislocation bands exhibit features of low dimensional chaos. This is made quantitative by demonstrating that the model equations can be approximately reduced to space independent model equations for the average dislocation densities, which is known to be low-dimensionally chaotic. However, the scaling regime for the correlation dimension shrinks with increasing applied strain rate due to increasing propensity for propagation of the dislocation bands.

Ritupan Sarmah; G. Ananthakrishna

2013-03-26T23:59:59.000Z

368

A Game-Dynamic Model of Gas Transportation Routes and Its Application . . .  

E-Print Network (OSTI)

The purpose of this paper is to study an optimal structure of a system of international gas pipelines competing for a gas market. We develop a game-dynamic model of the operation of several interacting gas pipeline projects with project owners acting as players in the game. The model treats the projects' commercialization times as major players' controls. Current quantities of gas supply are modeled as approximations to Nash equilibrium points in instantaneous "gas supply games", in which each player maximizes his/her current netprofit due to the sales of gas. We use the model to analyze the Turkish gas market, on which gas routes originating from Russia, Turkmenistan and Iran are competing. The analysis is carried out in three steps. At step 1, we model the operation of the pipelines as planned and estimate the associated profits. At step 2, we optimize individual projects, with respect to their profits, assuming that the other pipelines operate as planned. At step 3, we find numerical Nash equilibrium commercialization policies for the entire group of the pipelines. The simulations show the degrees to which the planned regimes are not optimal compared to the Nash equilibrium ones. Another observation is that in equilibrium regimes the pipelines are not always being run at their full capacities, which implies that the proposed pipeline capacities might not be optimal. The simulation results turn out to be moderately sensitive to changes in the discount rate and highly sensitive to changes in the price elasticity of gas demand.

Ger Klaassen; Ivan Matrosov; Alexander Roehrl; Alexander Tarasyev; Arkadii Kryazhimskii

2003-01-01T23:59:59.000Z

369

Modeling surfaces in the context of pulsed-power : work functions, electron emission and dynamic response.  

SciTech Connect

The ability to quickly understand and deal with issues on ZR, or to virtually design a future ZX accelerator, requires a physics-based capability to simulate all key pulsed power components. Highly important for gas switches and transmission lines are surface phenomena: thermionic emission, photoemission, field emission, and ion-surface dynamics. These are complex processes even at normal conditions, when coupled to the dynamic environment in pulsed power components, the current state of the art of understanding is not at the level of science based predictive modeling. Modeling efforts at the macroscopic level (finite element based hydrodynamic simulations) require detailed information of these processes to yield more reliable results. This is the final report of an LDRD project in the science of extreme environments investment area; the project was focused on describing the physics of surfaces of materials of interest in pulsed-power components. We have calculated the temperature dependence of work functions for metals from first principles using density functional theory (DFT) as well as investigated the effect of initial oxidation and alloying. By using the GW method, we have gone beyond DFT to calculate work functions for Al. The GW work required base-lining the GW results for different systems, since GW lacks a description of total energy. Lastly, we investigated the more macroscopic physics of how a surface and bulk material responds to a very high current under a short time, representative for current loads in pulsed-power components, with emphasis on materials modeling. These simulations were made using two hydrodynamic codes, ALEGRA and MACH2, in order to focus on the materials models themselves.

Cochrane, Kyle Robert (Ktech Corporation, Albuquerque, NM); Chantrenne, Sophie (SAIC, Albuquerque, NM); Mattsson, Thomas Kjell Rene; Faleev, Sergey V. (SNAMI Inc., AL)

2009-09-01T23:59:59.000Z

370

A simulation model of Rio Grande wild turkey dynamics in the Edwards Plateau of Texas  

E-Print Network (OSTI)

I investigated the effect of precipitation and predator abundance on Rio Grande wild turkey (Meleagris gallopavo; RGWT) in Texas. My results suggested that RGWT production was strongly correlated with cumulative winter precipitation over the range of the RGWT in Texas. However, I found no evidence that predator abundance influenced RGWT production, although spatial-asynchrony of predator populations at multiple spatial scales might have masked broad-scale effects. Using the results of these analyses, as well as empirical data derived from the literature and from field studies in the southern Edwards Plateau, I developed a stochastic, density-dependent, sex- and agespecific simulation model of wild turkey population dynamics. I used the model to evaluate the effect of alternative harvest management strategies on turkey populations. Sensitivity analysis of the model suggested that shape of the density-dependence relationship, clutch size, hatchability, juvenile sex ratio, poult survival, juvenile survival, and nonbreeding hen mortality most strongly influenced model outcome. Of these, density-dependence, sex ratio, and juvenile survival were least understood and merit further research. My evaluation of fall hen harvest suggested that current rates do not pose a threat to turkey populations. Moreover, it appears that hen harvest can be extended to other portions of the RGWT range without reducing turkey abundance, assuming that population dynamics and harvest rates are similar to those in the current fall harvest zone. Finally, simulation of alternative hen harvest rates suggested that rates ?5% of the fall hen population resulted in significant declines in the simulated population after 25 years, and rates ?15% resulted in significant risk of extinction to the simulated population.

Schwertner, Thomas Wayne

2003-05-01T23:59:59.000Z

371

Solar Pilot Plant, Phase I. Preliminary design report. Volume II, Book 3. Dynamic simulation model and computer program descriptions. CDRL item 2. [SPP dynamics simulation program  

DOE Green Energy (OSTI)

The mathematical models and computer program comprising the SPP Dynamic Simulation are described. The SPP Dynamic Simulation is a computerized model representing the time-varying performance characteristics of the SPP. The model incorporates all the principal components of the pilot plant. Time-dependent direct normal solar insulation, as corrupted by simulated cloud passages, is transformed into absorbed radiant power by actions of the heliostat field and enclosed receiver cavity. The absorbed power then drives the steam generator model to produce superheated steam for the turbine and/or thermal storage subsystems. The thermal storage subsystem can, in turn, also produce steam for the turbine. The turbine using the steam flow energy produces the mechanical shaft power necessary for the generator to convert it to electrical power. This electrical power is subsequently transmitted to a transmission grid system. Exhaust steam from the turbine is condensed, reheated, deaerated, and pressurized by pumps for return as feedwater to the thermal storage and/or steam generator. A master control/instrumentation system is utilized to coordinate the various plant operations. The master controller reacts to plant operator demands and control settings to effect the desired output response. The SPP Dynamic Simulation Computer program is written in FORTRAN language. Various input options (e.g., insolation values, load demands, initial pressures/temperatures/flows) are permitted. Plant performance may be monitored via computer printout or computer generated plots. The remainder of this document describes the detailed pilot plant dynamic model, the basis for this simulation, and the utilization of this simulation to obtain analytical plant performance results.

None

1977-05-01T23:59:59.000Z

372

Modeling aspects of the ecological and evolutionary dynamics of the endangered Houston toad  

E-Print Network (OSTI)

The goal of my dissertation was to describe the dynamics of a group of Houston toads located at the Griffith League Ranch (GLR), Bastrop County, Texas. My research included using statistical modeling to predict activity and abundance, mark-recapture techniques to estimate survivorship, and simulation modeling to explore the impacts of the difference in age at first reproduction and to project the future dynamics of the population at the GLR. From 2001 – 2005, 225 individual Houston toads (199 M : 26 F) were captured using two methods: breeding pond surveys and drift fences. Houston toads were neither caught equally among capture methods, nor across years. Toad activity was mostly confined within their breeding season, and activity was not continuous. A logistic regression indicated activity depended on time of year, mean precipitation, mean minimum daily temperature, and mean percent lunation as well as two-way interactions with moon-phase and other variables. Abundance depended on time of year, current precipitation, minimum temperature, and two-way interactions between time of year and the other two variables. Twenty-one of the 199 males (10.5%) and no females were recaptured among years. The probability of male survival was estimated using program MARK. Eight of 16 candidate models were supported and all but one contained precipitation as a covariate, indicating precipitation is important for Houston toad survival. Survivorship estimates varied from 0.1 to 0.41. The sex ratio was significantly male-biased. The odds of catching females in traps were 3.5 greater than capturing females in a pond, while the odds of capturing males in a trap were 0.28 compared to ponds. Results from a simulation model indicated the sex ratio is biased because of the difference in maturation times between males and females, coupled with high juvenile mortality. Results from an individual-based, spatially-explicit, stochastic simulation model, indicated a relatively low probability (~ 0.013) of B. houstonensis going extinct at the GLR within the next 10 years. Emergent properties of the model were similar to results observed in the field or reported in the literature. The model also identified that dispersal of Houston toads should be a future research priority.

Swannack, Todd Michael

2007-08-01T23:59:59.000Z

373

Quasi-explicit time-integration schemes for dynamic fracture with set-valued cohesive zone models  

Science Conference Proceedings (OSTI)

We investigate quasi-explicit time-integration schemes for solving dynamic fracture problems with set-valued cohesive zone models. These schemes combine a central difference time-integration scheme and a partially implicit and lumped treatment of the ... Keywords: Cohesive zone model, Finite elements, Time-integration scheme

D. Doyen; A. Ern; S. Piperno

2013-08-01T23:59:59.000Z

374

Improved interval estimation of long run response from a dynamic linear model: A highest density region approach  

Science Conference Proceedings (OSTI)

This paper proposes a new method of interval estimation for the long run response (or elasticity) parameter from a general linear dynamic model. We employ the bias-corrected bootstrap, in which small sample biases associated with the parameter estimators ... Keywords: ARDL model, Bias-correction, Bootstrapping, Highest density region, Long run elasticity

Jae H. Kim; Iain Fraser; Rob J. Hyndman

2011-08-01T23:59:59.000Z

375

A model of shape memory materials with hierarchical twinning: Statics and dynamics  

SciTech Connect

We consider a model of shape memory material in which hierarchical twinning near the habit plane (austenite-martensite interface) is a new and crucial ingredient. The model includes (1) a triple-well potential ({phi} model) in local shear strain, (2) strain gradient terms up to second order in strain and fourth order in gradient, and (3) all symmetry allowed compositional fluctuation induced strain gradient terms. The last term favors hierarchy which enables communication between macroscopic (cm) and microscopic ({Angstrom}) regions essential for shape memory. Hierarchy also stabilizes between formation (critical pattern of twins). External stress or pressure (pattern) modulates the spacing of domain walls. Therefore the ``pattern`` is encoded in the modulated hierarchical variation of the depth and width of the twins. This hierarchy of length scales provides a hierarchy of time scales and thus the possibility of non-exponential decay. The four processes of the complete shape memory cycle -- write, record, erase and recall -- are explained within this model. Preliminary results based on 2D Langevin dynamics are shown for tweed and hierarchy formation.

Saxena, A.; Bishop, A.R. [Los Alamos National Lab., NM (United States); Shenoy, S.R. [International Center for Theoretical Physics, Trieste (Italy); Wu, Y.; Lookman, T. [Western Ontario Univ., London, Ontario (Canada). Dept. of Applied Mathematics

1995-07-01T23:59:59.000Z

376

History dependent dynamics in a generic model of ion channels - an analytic study  

E-Print Network (OSTI)

Recent experiments have demonstrated that the timescale of adaptation of single neurons and ion channel populations to stimuli slows down as the length of stimulation increases; in fact, no upper bound on temporal time-scales seems to exist in such systems. Furthermore, patch clamp experiments on single ion channels have hinted at the existence of large, mostly unobservable, inactivation state spaces within a single ion channel. This raises the question of the relation between this multitude of inactivation states and the observed behavior. In this work we propose a minimal model for ion channel dynamics which does not assume any specific structure of the inactivation state space. The model is simple enough to render an analytical study possible. This leads to a clear and concise explanation of the experimentally observed exponential history-dependent relaxation in sodium channels in a voltage clamp setting, and shows that their recovery rate from slow inactivation must be voltage dependent. Furthermore, we predict that history-dependent relaxation cannot be created by overly sparse spiking activity. While the model was created with ion channel populations in mind, its simplicity and genericalness render it a good starting point for modeling similar effects in other systems, and for scaling up to higher levels such as single neurons which are also known to exhibit multiple time scales.

Daniel Soudry; Ron Meir

2009-12-20T23:59:59.000Z

377

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

378

Review A New Tool for Epidemiology: The Usefulness of Dynamic-Agent Models in Understanding Place Effects on Health  

E-Print Network (OSTI)

A major focus of recent work on the spatial patterning of health has been the study of how features of residential environments or neighborhoods may affect health. Place effects on health emerge from complex interdependent processes in which individuals interact with each other and their environment and in which both individuals and environments adapt and change over time. Traditional epidemiologic study designs and statistical regression approaches are unable to examine these dynamic processes. These limitations have constrained the types of questions asked, the answers received, and the hypotheses and theoretical explanations that are developed. Agent-based models and other systems-dynamics models may help to address some of these challenges. Agent-based models are computer representations of systems consisting of heterogeneous microentities that can interact and change/adapt over time in response to other agents and features of the environment. Using these models, one can observe how macroscale dynamics emerge from microscale interactions and adaptations. A number of challenges and limitations exist for agent-based modeling. Nevertheless, use of these dynamic models may complement traditional epidemiologic analyses and yield additional insights into the processes involved and the interventions that may be most useful. computer simulation; environment and public health; epidemiologic methods; health behavior; models, theoretical; residence characteristics; systems theory

Amy H. Auchincloss; Ana V. Diez Roux

2007-01-01T23:59:59.000Z

379

Geometric phase effects in low-energy dynamics near conical intersections: A study of the multidimensional linear vibronic coupling model  

E-Print Network (OSTI)

In molecular systems containing conical intersections (CIs), a nontrivial geometric phase (GP) appears in the nuclear and electronic wave-functions in the adiabatic representation. We study GP effects in nuclear dynamics of an N-dimensional linear vibronic coupling (LVC) model. The main impact of GP on low-energy nuclear dynamics is reduction of population transfer between the local minima of the LVC lower energy surface. For the LVC model, we proposed an isometric coordinate transformation that confines non-adiabatic effects within a two-dimensional subsystem interacting with an N-2 dimensional environment. Since environmental modes do not couple electronic states, all GP effects originate from nuclear dynamics within the subsystem. We explored when the GP affects nuclear dynamics of the isolated subsystem, and how the subsystem-environment interaction can interfere with GP effects. Comparing quantum dynamics with and without GP allowed us to devise simple rules to determine significance of the GP for nuclear dynamics in this model.

Loic Joubert-Doriol; Ilya G. Ryabinkin; Artur F. Izmaylov

2013-10-10T23:59:59.000Z

380

Mercury's spin-orbit model and signature of its dynamical parameters  

E-Print Network (OSTI)

The 3:2 spin-orbit resonance between the rotational and orbital motions of Mercury results from a functional dependance on a tidal friction adding to a non-zero eccentricity with a permanent asymmetry in the equatorial plane of the planet. The upcoming space missions, MESSENGER and BepiColombo with onboard instrumentation capable of measuring the Mercury's rotational parameters, stimulate the objective to attempt to an accurate theory of the planet's rotation. We have used our BJV relativistic model of solar system integration including the spin-orbit motion of the Moon. This model had been previously built in accordance with the requirements of the Lunar Laser Ranging observational accuracy. We extended this model to the spin-orbit couplings of the terrestrial planets including Mercury; the updated model is called SONYR (acronym of Spin-Orbit N-BodY Relativistic model). An accurate rotation of Mercury has been then obtained. Moreover, the conception of the SONYR model is suitable for analyzing the different families of hermean rotational librations. We accurately identify the non-linear relations between the rotation of Mercury and its dynamical figure (\\cmr2, $C_{20}$, and $C_{22}$). Notably, for a variation of 1% on the \\cmr2 value, signatures in the $\\phi$ hermean libration in longitude as well as in the $\\eta$ obliquity of the planet are respectively 0.45 arcseconds (as) and 2.4 milliarcseconds (mas). These determinations provide new constraints on the internal structure of Mercury to be discussed with the expected accuracy forecasted in the BepiColombo mission (respectively 3.2 and 3.7 as according to Milani et al 2001).

Nicolas Rambaux; Eric Bois

2003-07-17T23:59:59.000Z

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381

Star Clusters with Primordial Binaries: II. Dynamical Evolution of Models in a Tidal Field  

E-Print Network (OSTI)

[abridged] We extend our analysis of the dynamical evolution of simple star cluster models, in order to provide comparison standards that will aid in interpreting the results of more complex realistic simulations. We augment our previous primordial-binary simulations by introducing a tidal field, and starting with King models of different central concentrations. We present the results of N-body calculations of the evolution of equal-mass models, starting with primordial binary fractions of 0 - 100 %, and N values from 512 to 16384. We also attempt to extrapolate some of our results to the larger number of particles that are necessary to model globular clusters. We characterize the steady-state `deuterium main sequence' phase in which primordial binaries are depleted in the core in the process of `gravitationally burning'. In this phase we find that the ratio of the core to half-mass radius, r_c/r_h, is similar to that measured for isolated systems. In addition to the generation of energy due to hardening and depletion of the primordial binary population, the overall evolution of the star clusters is driven by a competing process: the tidal disruption of the system. We find that the depletion of primordial binaries before tidal dissolution of the system is possible only if the initial number is below 0.05 N, in the case of a King model with W_0=7 and N=4096 (which is one of our longest living models). We compare our findings, obtained by means of direct N-body simulations but scaled, where possible, to larger N, with similar studies carried out by means of Monte Carlo methods.

M. Trenti; D. C. Heggie; P. Hut

2006-02-17T23:59:59.000Z

382

The dynamics of scalar-tensor cosmology from RS two-brane model  

E-Print Network (OSTI)

We consider a Randall-Sundrum two-brane cosmological model in the low energy gradient expansion approximation by Kanno and Soda. It is a scalar-tensor theory with a specific coupling function and a specific potential. Upon introducing the FLRW metric and perfect fluid matter on both branes in the Jordan frame, the effective dynamical equation for the the A-brane (our Universe) scale factor decouples from the scalar field and B-brane matter leaving only a non-vanishing integration constant (the dark radiation term). We find exact solutions for the A-brane scale factor for four types of matter: cosmological constant, radiation, dust, and cosmological constant plus radiation. We perform a complementary analysis of the dynamics of the scalar field (radion) using phase space methods and examine convergence towards the limit of general relativity. In particular, we find that radion stabilizes at a certain finite value for suitable negative matter densities on the B-brane. Observational constraints from Solar system experiments (PPN) and primordial nucleosynthesis (BBN) are also briefly discussed.

Laur Jarv; Piret Kuusk; Margus Saal

2006-08-24T23:59:59.000Z

383

High accuracy power spectra including baryonic physics in dynamical Dark Energy models  

E-Print Network (OSTI)

The next generation mass probes will obtain information on non--linear power spectra P(k,z) and their evolution, allowing us to investigate the nature of Dark Energy. To exploit such data we need high precision simulations, extending at least up to scales of k\\simeq 10 h^-1 Mpc, where the effects of baryons can no longer be neglected. In this paper, we present a series of large scale hydrodynamical simulations for LCDM and dynamical Dark Energy (dDE) models, in which the equation of state parameter is z-dependent. The simulations include gas cooling, star formation and Supernovae feedback. They closely approximate the observed star formation rate and the observationally derived star/Dark Matter mass ratio in collapsed systems. Baryon dynamics cause spectral shifts exceeding 1% at k > 2-3 hMpc^-1 compared to pure n-body simulations in the LCDM simulations. This agrees with previous studies, although we find a smaller effect (~50%) on the power spectrum amplitude at higher k's. dDE exhibits similar behavior, ev...

Casarini, Luciano; Bonometto, Silvio A; Stinson, Greg S

2010-01-01T23:59:59.000Z

384

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

385

HyDIVE (Hydrogen Dynamic Infrastructure and Vehicle Evolution) Model Analysis  

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

HyDIVE(tm) HyDIVE(tm) (Hydrogen Dynamic Infrastructure and Vehicle Evolution) model analysis Cory Welch Hydrogen Analysis Workshop, August 9-10 Washington, D.C. Disclaimer and Government License This work has been authored by Midwest Research Institute (MRI) under Contract No. DE- AC36-99GO10337 with the U.S. Department of Energy (the "DOE"). The United States Government (the "Government") retains and the publisher, by accepting the work for publication, acknowledges that the Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for Government purposes. Neither MRI, the DOE, the Government, nor any other agency thereof, nor any of their

386

Modeling and Control of Lean Premixed Combustion Dynamics for Gas Turbines  

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

Virginia Active Combustion Control Group Virginia Active Combustion Control Group Tech Virginia VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY Reacting Flows Laboratory Modeling and Control of Lean Premixed Combustion Dynamics for Gas Turbines Virginia Tech Principal Investigator: Uri Vandsburger SCIES Project 02- 01- SR099 DOE COOPERATIVE AGREEMENT DE-FC26-02NT41431 Tom J. George, Program Manager, DOE/NETL Richard Wenglarz, Manager of Research, SCIES Project Awarded (05/01/02, 36 Month Duration) $ 756,700 Total Contract Value ($ 603,600 DOE) Virginia Active Combustion Control Group Tech Virginia VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY Reacting Flows Laboratory Gas Turbine Technology Needs DLN/LP Gas Turbines * Improved Combustion Stability * Improved Design Methodology With a focus on: - Thermoacoustics

387

Liquefied Natural Gas (LNG) Vapor Dispersion Modeling with Computational Fluid Dynamics Codes  

E-Print Network (OSTI)

Federal regulation 49 CFR 193 and standard NFPA 59A require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. For modeling purposes, the physical process of dispersion of LNG release can be simply divided into two stages: source term and atmospheric dispersion. The former stage occurs immediately following the release where the behavior of fluids (LNG and its vapor) is mainly controlled by release conditions. After this initial stage, the atmosphere would increasingly dominate the vapor dispersion behavior until it completely dissipates. In this work, these two stages are modeled separately by a source term model and a dispersion model due to the different parameters used to describe the physical process at each stage. The principal focus of the source term study was on LNG underwater release, since there has been far less research conducted in developing and testing models for the source of LNG release underwater compared to that for LNG release onto land or water. An underwater LNG release test was carried out to understand the phenomena that occur when LNG is released underwater and to determine the characteristics of pool formation and the vapor cloud generated by the vaporization of LNG underwater. A mathematical model was used and validated against test data to calculate the temperature of the vapor emanating from the water surface. This work used the ANSYS CFX, a general-purpose computational fluid dynamics (CFD) package, to model LNG vapor dispersion in the atmosphere. The main advantages of CFD codes are that they have the capability of defining flow physics and allowing for the representation of complex geometry and its effects on vapor dispersion. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the mesh size and shape, atmospheric conditions, turbulence from the source term, ground surface roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate the impact of key parameters on the accuracy of simulation results. In addition, a series of medium-scale LNG spill tests have been performed at the Brayton Fire Training Field (BFTF), College Station, TX. The objectives of these tests were to study key parameters of modeling the physical process of LNG vapor dispersion and collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX described the physical behavior of LNG vapor dispersion well, and its prediction results of distances to the half lower flammable limit were in good agreement with the test data.

Qi, Ruifeng

2011-08-01T23:59:59.000Z

388

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

389

Developing a computationally efficient dynamic multilevel hybrid optimization scheme using multifidelity model interactions.  

SciTech Connect

Many engineering application problems use optimization algorithms in conjunction with numerical simulators to search for solutions. The formulation of relevant objective functions and constraints dictate possible optimization algorithms. Often, a gradient based approach is not possible since objective functions and constraints can be nonlinear, nonconvex, non-differentiable, or even discontinuous and the simulations involved can be computationally expensive. Moreover, computational efficiency and accuracy are desirable and also influence the choice of solution method. With the advent and increasing availability of massively parallel computers, computational speed has increased tremendously. Unfortunately, the numerical and model complexities of many problems still demand significant computational resources. Moreover, in optimization, these expenses can be a limiting factor since obtaining solutions often requires the completion of numerous computationally intensive simulations. Therefore, we propose a multifidelity optimization algorithm (MFO) designed to improve the computational efficiency of an optimization method for a wide range of applications. In developing the MFO algorithm, we take advantage of the interactions between multi fidelity models to develop a dynamic and computational time saving optimization algorithm. First, a direct search method is applied to the high fidelity model over a reduced design space. In conjunction with this search, a specialized oracle is employed to map the design space of this high fidelity model to that of a computationally cheaper low fidelity model using space mapping techniques. Then, in the low fidelity space, an optimum is obtained using gradient or non-gradient based optimization, and it is mapped back to the high fidelity space. In this paper, we describe the theory and implementation details of our MFO algorithm. We also demonstrate our MFO method on some example problems and on two applications: earth penetrators and groundwater remediation.

Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Gray, Genetha Anne (Sandia National Laboratories, Livermore, CA); Castro, Joseph Pete Jr. (; .); Giunta, Anthony Andrew

2006-01-01T23:59:59.000Z

390

Explicit/multi-parametric model predictive control (MPC) of linear discrete-time systems by dynamic and multi-parametric programming  

Science Conference Proceedings (OSTI)

This work presents a new algorithm for solving the explicit/multi-parametric model predictive control (or mp-MPC) problem for linear, time-invariant discrete-time systems, based on dynamic programming and multi-parametric programming techniques. The ... Keywords: Dynamic programming, Explicit Model Predictive Control, Model Predictive Control, Multi-parametric control, Multi-parametric programming

K. I. Kouramas; N. P. Faísca; C. Panos; E. N. Pistikopoulos

2011-08-01T23:59:59.000Z

391

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

392

Wind Turbine Modeling for Computational Fluid Dynamics: December 2010 - December 2012  

DOE Green Energy (OSTI)

With the shortage of fossil fuel and the increasing environmental awareness, wind energy is becoming more and more important. As the market for wind energy grows, wind turbines and wind farms are becoming larger. Current utility-scale turbines extend a significant distance into the atmospheric boundary layer. Therefore, the interaction between the atmospheric boundary layer and the turbines and their wakes needs to be better understood. The turbulent wakes of upstream turbines affect the flow field of the turbines behind them, decreasing power production and increasing mechanical loading. With a better understanding of this type of flow, wind farm developers could plan better-performing, less maintenance-intensive wind farms. Simulating this flow using computational fluid dynamics is one important way to gain a better understanding of wind farm flows. In this study, we compare the performance of actuator disc and actuator line models in producing wind turbine wakes and the wake-turbine interaction between multiple turbines. We also examine parameters that affect the performance of these models, such as grid resolution, the use of a tip-loss correction, and the way in which the turbine force is projected onto the flow field.

Tossas, L. A. M.; Leonardi, S.

2013-07-01T23:59:59.000Z

393

Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution  

E-Print Network (OSTI)

In the present paper we derive the density distribution of dark matter (DM) in a well-observed nearby disc galaxy, the Andromeda galaxy. From photometrical and chemical evolution models constructed in the first part of the study (Tamm, Tempel & Tenjes 2007 (arXiv:0707.4375), hereafter Paper I) we can calculate the mass distribution of visible components. In the dynamical model we calculate stellar rotation velocities along the major axis and velocity dispersions along the major, minor and intermediate axes of the galaxy. Comparing the calculated values with the collected observational data, we find the amount of DM, which must be added to reach an agreement with the observed rotation and dispersion data. We conclude that within the uncertainties, the DM distributions by Moore, Burkert, isothermal, Navarro, Frenk & White (NFW) and Navarro et al. 2004 (N04) fit with observations. The NFW and N04 density distributions give the best fit with observations. The total mass of M 31 with the NFW DM distributio...

Tempel, Elmo; Tenjes, Peeter

2007-01-01T23:59:59.000Z

394

Model-Based Methodology for Building Confidence in a Dynamic Measuring System  

E-Print Network (OSTI)

This thesis examines the special case in which a newly developed dynamic measurement system must be characterized when an accepted standard qualification procedure does not yet exist. In order to characterize this type of system, both physical experimentation and computational simulation methods will be used to build trust in this measurement system. This process of establishing credibility will be presented in the form of a proposed methodology. This proposed methodology will utilize verification and validation methods that apply within the simulation community as the foundation for this multi-faceted approach. The methodology will establish the relationships between four key elements: physical experimentation, conceptual modeling, computational simulations, and data processing. The combination of these activities will provide a comprehensive characterization study of the system. In order to illustrate the methodology, a case study was performed on a dynamic force measurement system owned by Sandia National Laboratories. This system was designed to measure the force required to pull a specimen to failure in tension at a user-input velocity. The results of the case study found that there was a significant measurement error occurring as the pull event involved large break loads and high velocities. 100 pull events were recorded using an experimental test assembly. The highest load conditions discovered a force measurement error of over 100%. Using computational simulations, this measurement error was reduced to less than 10%. These simulations were designed to account for the inertial effects that skew the piezoelectric load cells. This thesis displays the raw data and the corrected data for five different pull settings. The simulations designed using the methodology significantly reduced the error in all five pull settings. In addition to the force analysis, the simulations provide insight into the complete system performance. This includes the analysis of the maximum system velocity as well as the analysis of several proposed design changes. The findings suggest that the dynamic measurement system has a maximum velocity of 28 fps, and that this maximum velocity is unaffected by the track length or the mass of the moving carriage.

Reese, Isaac Mark

2013-05-01T23:59:59.000Z

395

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

396

Scientific Final Report: COLLABORATIVE RESEARCH: CONTINUOUS DYNAMIC GRID ADAPTATION IN A GLOBAL ATMOSPHERIC MODEL: APPLICATION AND REFINEMENT  

SciTech Connect

This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the 'physics' of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.

William J. Gutowski; Joseph M. Prusa, Piotr K. Smolarkiewicz

2012-04-09T23:59:59.000Z

397

Simulation model and the dynamics of relative poverty rates in the presence of some social benefits in Romania  

Science Conference Proceedings (OSTI)

This paper presents some simulations of the relative poverty rates values in the presence of some social benefits in the income of persons / households considered in the Household Budget Survey carried out by the National Institute of Statistics of Romania ... Keywords: dynamics, indicators, relative poverty, simulation model, social benefits

Cristina Stroe; Andreea Cambir; Cornelia Barti; Eva Militaru; Silvia Cojanu; Eliza Lungu; Codruta Dragoiu; Isadora Lazar

2011-07-01T23:59:59.000Z

398

An Accurate Radiative Heating and Cooling Algorithm for Use in a Dynamical Model of the Middle Atmosphere  

Science Conference Proceedings (OSTI)

An infrared radiative heating and cooling algorithm designed to be used with dynamical models of the middle atmosphere is described. A Curtis matrix is used to compute cooling by the 15 and 10 ?m bands of carbon dioxide. Escape of radiation to ...

W. M. Wehrbein; C. B. Leovy

1982-07-01T23:59:59.000Z

399

Estimation dynamical model of an anaerobic digestion of shrimp culture pond sediment in a biogas process using genetic algorithm  

Science Conference Proceedings (OSTI)

Biogas is one type of renewable energy which is important to the energy and environmental planning of Thailand. The study and analysis of the dynamical model of the biogas process can be explained the variables that affect biogas process and optimization. ... Keywords: anaerobic digestion, artificial intelligence, biogas process, mass balance equation, system identification

Jiraphon Srisertpol; Prasit Srinakorn; Adtavirod Kheawnak; Kontorn Chamniprasart; Arthit Srikaew

2010-10-01T23:59:59.000Z

400

Repetitive Decision Making and the Value of Forecasts in the Cost?Loss Ratio Situation: A Dynamic Model  

Science Conference Proceedings (OSTI)

The purposes of this paper are to describe a dynamic model for repetitive decision?making in the cost–loss ratio situation and to present some theoretical and numerical results related to the optimal use and economic value of weather forecasts ...

Allan H. Murphy; Richard W. Katz; Robert L. Winkler; Wu-Ron Hsu

1985-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics model redyn" 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

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

402

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)

403

Dynamic modeling to minimize energy use for CO{sub 2} capture in power plants by aqueous monoethanolamine  

SciTech Connect

A dynamic rate-based model was developed for stripping in CO{sub 2} capture from coal-fired power plants with 30 wt% monoethanolamine (MEA). The model, created in a flow sheet of Aspen Custom Modeler, was based on the film theory for liquid and vapor phases. It takes into account the impact of equilibrium reactions on the mass transfer, thermodynamic nonidealities, and the hydraulics of the structured packing. With this model, steady state analyses were. carried out for the stripper to understand the effect of the leah loading and the height of the packing on total equivalent work and find optimum operating conditions that minimize power plant lost work. Two dynamic strategies with control configurations are proposed to run the stripper in a flexible operation during the period of electricity peak load and prices. Open loop responses demonstrated some differences in dynamic behavior and steady state values for proposed dynamic strategies. One of the approaches increased the CO{sub 2} removal by 1% at the reduced steam rate and provided faster response of the stripper to a step change in the reboiler heat rate.

Ziaii, S.; Rochelle, G.T.; Edgar, T.F. [University of Texas Austin, Austin, TX (United States). Dept. of Chemical Engineering

2009-07-15T23:59:59.000Z

404

Linear versus Nonlinear Filtering with Scale-Selective Corrections for Balanced Dynamics in a Simple Atmospheric Model  

Science Conference Proceedings (OSTI)

This paper investigates the role of the linear analysis step of the ensemble Kalman filters (EnKF) in disrupting the balanced dynamics in a simple atmospheric model and compares it to a fully nonlinear particle-based filter (PF). The filters have ...

Aneesh C. Subramanian; Ibrahim Hoteit; Bruce Cornuelle; Arthur J. Miller; Hajoon Song

2012-11-01T23:59:59.000Z

405

A multi-formalism approach for model-based dynamic distribution of user interfaces of critical interactive systems  

Science Conference Proceedings (OSTI)

Evolution in the context of use requires evolutions in the user interfaces even when they are currently used by operators. User Centered Development promotes reactive answers to this kind of evolutions either by software evolutions through iterative ... Keywords: Automation, Distributed user interfaces, Dynamic reconfiguration of user interfaces, Formal description techniques, Interactive software engineering, Model-based approaches

Célia Martinie, David Navarre, Philippe Palanque

2014-01-01T23:59:59.000Z

406

Nonlinear Dynamics in an OLG Growth Model with Young and Old Age Labour Supply: The Role of Public Health Expenditure  

Science Conference Proceedings (OSTI)

This study analyses the dynamics of a two-dimensional overlapping generations economy with young and old age labour supply. We show that the public provision of investments in health, which, in turn, affects the demand for material consumption of the ... Keywords: C62, C68, Chaos, I18, J22, Labour supply, O41, OLG model, Public health expenditure

Luca Gori; Mauro Sodini

2011-10-01T23:59:59.000Z

407

Visible and dark matter in M 31 - II. A dynamical model and dark matter density distribution  

E-Print Network (OSTI)

In the present paper we derive the density distribution of dark matter (DM) in a well-observed nearby disc galaxy, the Andromeda galaxy. From photometrical and chemical evolution models constructed in the first part of the study (Tamm, Tempel & Tenjes 2007 (arXiv:0707.4375), hereafter Paper I) we can calculate the mass distribution of visible components (the bulge, the disc, the stellar halo, the outer diffuse stellar halo). In the dynamical model we calculate stellar rotation velocities along the major axis and velocity dispersions along the major, minor and intermediate axes of the galaxy assuming triaxial velocity dispersion ellipsoid. Comparing the calculated values with the collected observational data, we find the amount of DM, which must be added to reach an agreement with the observed rotation and dispersion data. We conclude that within the uncertainties, the DM distributions by Moore, Burkert, Navarro, Frenk & White (NFW) and the Einasto fit with observations nearly at all distances. The NFW and Einasto density distributions give the best fit with observations. The total mass of M 31 with the NFW DM distribution is 1.19*10^12 M_sun, the ratio of the DM mass to the visible mass is 10.0. For the Einasto DM distribution, these values are 1.28*10^12 M_sun and 10.8. The ratio of the DM mass to the visible mass inside the Holmberg radius is 1.75 for the NFW and the Einasto distributions. For different cuspy DM distributions, the virial mass is in a range 6.9-7.9*10^11 M_sun and the virial radius is ~150 kpc. The DM mean densities inside 10 pc for cusped models are 33 and 16 M_sun pc^-3 for the NFW and the Einasto profiles, respectively. For the cored Burkert profile, this value is 0.06 M_sun pc^-3.

Elmo Tempel; Antti Tamm; Peeter Tenjes

2007-07-30T23:59:59.000Z

408

Dynamics of the UK Natural Gas Industry: System Dynamics Modelling and Long-Term Energy Policy Analysis  

E-Print Network (OSTI)

case of indigenous UK gas production. Firstly, the structure of Naill’s model (1973) implies that production rate equals usage rate, modified by price. We find this assumption to be unrealistic in our case and therefore we explicitly model... considerably over the time horizon. In the initial period of introduction of gas usage in UK 1965-1974 average annual growth rate was 48%; in the period 1975-1984 average growth rate was 3.31%; in the period 1985-1995 average growth rate was 3%; in the period...

Chi, K C; Reiner, David; Nuttall, William J

409

On the Application of the Dynamic Smagorinsky Model to Large-Eddy Simulations of the Cloud-Topped Atmospheric Boundary Layer  

Science Conference Proceedings (OSTI)

In this paper the dynamic Smagorinsky model originally developed for engineering flows is adapted for simulations of the cloud-topped atmospheric boundary layer in which an anelastic form of the governing equations is used. The adapted model ...

M. P. Kirkpatrick; A. S. Ackerman; D. E. Stevens; N. N. Mansour

2006-02-01T23:59:59.000Z

410

Dynamical Downscaling over the Great Lakes Basin of North America Using the WRF Regional Climate Model: The Impact of the Great Lakes System on Regional Greenhouse Warming  

Science Conference Proceedings (OSTI)

The Weather Research and Forecasting model (WRF) is employed to dynamically downscale global warming projections produced using the Community Climate System Model (CCSM). The analyses are focused on the Great Lakes Basin of North America and the ...

Jonathan Gula; W. Richard Peltier

2012-11-01T23:59:59.000Z

411

Global Vegetation and Climate Change due to Future Increases in CO2 as Projected by a Fully Coupled Model with Dynamic Vegetation  

Science Conference Proceedings (OSTI)

Transient simulations are presented of future climate and vegetation associated with continued rising levels of CO2. The model is a fully coupled atmosphere–ocean–land–ice model with dynamic vegetation. The impacts of the radiative and ...

Michael Notaro; Steve Vavrus; Zhengyu Liu

2007-01-01T23:59:59.000Z

412

Primitive-Equation-Based Low-Order Models with Seasonal Cycle. Part II: Application to Complexity and Nonlinearity of Large-Scale Atmosphere Dynamics  

Science Conference Proceedings (OSTI)

A recently developed class of semiempirical low-order models is utilized for the reexamination of several aspects of the complexity and nonlinearity of large-scale dynamics in a GCM. Given their low dimensionality, these models are quite ...

Ulrich Achatz; J. D. Opsteegh

2003-02-01T23:59:59.000Z

413

Evaluation of the New CNDV Option of the Community Land Model: Effects of Dynamic Vegetation and Interactive Nitrogen on CLM4 Means and Variability  

Science Conference Proceedings (OSTI)

The Community Land Model, version 4 (CLM4) includes the option to run the prognostic carbon–nitrogen (CN) model with dynamic vegetation (CNDV). CNDV, which simulates unmanaged vegetation, modifies the CN framework to implement plant biogeography ...

C. Kendra Gotangco Castillo; Samuel Levis; Peter Thornton

2012-06-01T23:59:59.000Z

414

Seasonal Near-Surface Dynamics and Thermodynamics of the Indian Ocean and Indonesian Throughflow in a Global Ocean General Circulation Model  

Science Conference Proceedings (OSTI)

The near-surface dynamics and thermodynamics of the Indian Ocean are examined in a global ocean general circulation model (OGCM) with enhanced tropical resolution. The model uses a Seager-type heat flux formulation (weak relaxation toward a fixed ...

A. Schiller; J. S. Godfrey; P. C. McIntosh; G. Meyers; S. E. Wijffels

1998-11-01T23:59:59.000Z

415

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

416

Modeling and Compensation of the Dynamic Interaction of a Mobile Manipulator  

E-Print Network (OSTI)

A mobile manipulator composed of a manipulator and a mobile platform has a much larger workspace than a fixed-base manipulator. While the on-board manipulator reaches out and performs manipulation tasks, the role of the mobile platform is to position the manipulator in a preferred configuration. In this paper, we study the effect of the dynamic interaction between the manipulator and the mobile platform of a mobile manipulator on the task performance. We consider the task that the end point of the manipulator tracks a desired trajectory in a fixed reference frame. The effect of the dynamic interaction on the tracking performance is examined by comparing four different cases: (1) without any compensation of the dynamic interaction at all; (2) the mobile platform compensates the dynamic interaction caused by the manipulator; (3) the manipulator compensates the dynamic interaction caused by the mobile platform; and (4) with full compensation of the dynamic interaction with each other. 1 ...

Yoshio Yamamoto; Xiaoping Yun

1994-01-01T23:59:59.000Z

417

Hawaii International Conference on System Sciences, January 3-6, 2001, Maui, Hawaii. 2001 IEEE Modeling Blackout Dynamics in Power Transmission Networks  

E-Print Network (OSTI)

dynamics of cascading overloads and outages. The model dynamics are demonstrated on the simple power system to the time series of historical data for North American power grid blackouts. The sandpile was not a model from the historical data for North American power grid blackouts. Here we describe the implementation

418

Integrating high-precision U-Pb geochronologic data with dynamic models of earth processes  

E-Print Network (OSTI)

Radioisotopic dating can provide critical constraints for understanding the rates of tectonic, dynamic and biologic processes operating on our planet. Improving the interpretation and implementation of geochronologic data ...

Blackburn, Terrence (Terrence Joseph)

2012-01-01T23:59:59.000Z

419

A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras...  

Open Energy Info (EERE)

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...

420

Quasi-static and dynamic responses of advanced high strength steels: Experiments and modeling  

Science Conference Proceedings (OSTI)

Measured responses of advanced high strength steels (AHSS) and their tailor welded blanks (TWBs), over a wide range of strain-rates (10*4 to 103 s*1) are presented. The steels investigated include transformation induced plasticity (TRIP), dual phase (DP), and drawing quality (DQ) steels. The TWBs include DQ-DQ and DP-DP laser welds. A tensile split Hopkinson pressure bar (SHPB) was used for the dynamic experiments. AHSS and their TWB's were found to exhibit positive strain-rate sensitivity. The Khan-Huang-Liang (KHL) constitutive model is shown to correlate and predict the observed responses reasonably well. Micro-texture characterization of DQ steels, DQ-DQ and DP-DP laser welds were performed to investigate the effect of strain-rate on texture evolution of these materials. Electron backscatter diffraction (EBSD) technique was used to analyze the micro-texture evolution and kernel average misorientation (KAM) map. Measurement of micro-hardness profile across the cross section of tensile samples was conducted to understand the effect of initial microstructure on ductility of laser weld samples.

Khan, Akhtar; Baig, Muneer; Choi, Shi Hoon; Yang, Hoe Seok; Sun, Xin

2012-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "dynamics model redyn" 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

Dynamic Modeling and Simulation Based Analysis of an Ammonia Borane (AB) Reactor System for Hydrogen Storage  

DOE Green Energy (OSTI)

Research on ammonia borane (AB, NH3BH3) has shown it to be a promising material for chemical hydrogen storage in PEM fuel cell applications. AB was selected by DOE’s Hydrogen Storage Engineering Center of Excellence (HSECoE) as the initial chemical hydride of study because of its high hydrogen storage capacity (up to 19.6% by weight for the release of three molar equivalents of hydrogen gas) and its stability under typical ambient conditions. A model of a bead reactor system which includes feed and product tanks, hot and cold augers, a ballast tank/reactor, a H2 burner and a radiator was developed to study AB system performance in an automotive application and estimate the energy, mass, and volume requirements for this off-board regenerable hydrogen storage material. Preliminary system simulation results for a start-up case and for a transient drive cycle indicate appropriate trends in the reactor system dynamics. A new controller was developed and validated in simulation for a couple of H2 demand cases.

Devarakonda, Maruthi N.; Holladay, Jamelyn D.; Brooks, Kriston P.; Rassat, Scot D.; Herling, Darrell R.

2010-10-02T23:59:59.000Z

422

Kinetics and dynamic modelling of batch anaerobic digestion of municipal solid waste in a stirred reactor  

SciTech Connect

A series of batch, slurry anaerobic digestion experiments were performed where the soluble and insoluble fractions, and unwashed MSW were separately digested in a 200 l stirred stainless steel vessel at a pH of 7.2 and a temperature of 38 deg. C. It was found that 7% of the total MSW COD was readily soluble, of which 80% was converted to biogas; 50% of the insoluble fraction was solubilised, of this only 80% was converted to biogas. The rate of digesting the insoluble fraction was about four times slower than the rate of digesting the soluble fraction; 48% of the total COD was converted to biogas and 40% of the total nitrogen was converted to ammonia. Soluble and insoluble fractions were broken down simultaneously. The minimum time to convert 95% of the degradable fraction to biogas was 20 days. The lag phase for the degradation of insoluble fraction of MSW can be overcome by acclimatising the culture with the soluble fraction. The rate of digestion and the methane yield was not affected by particle size (within the range of 2-50 mm). A dynamic model was developed to describe batch digestion of MSW. The parameters of the model were estimated using data from the separate digestion of soluble and insoluble fractions and validated against data from the digestion of unwashed MSW. Trends in the specific aceticlastic and formate-utilising methanogenic activity were used to estimate initial methanogenic biomass concentration and bacterial death rate coefficient. The kinetics of hydrolysis of insoluble fraction could be adequately described by a Contois equation and the kinetics of acidogenesis, and aceticlastic and hydrogen utilising methanogenesis by Monod equations.

Nopharatana, Annop [Division of Environmental of Engineering, The University of Queensland, Brisbane, Qld. 4072 (Australia); Pilot Plant Development and Training Institute, King Mongkut's University of Technology, Thonburi, Bangkok 10150 (Thailand); Pullammanappallil, Pratap C. [Division of Environmental of Engineering, The University of Queensland, Brisbane, Qld. 4072 (Australia); Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611 (United States); Clarke, William P. [Division of Environmental of Engineering, The University of Queensland, Brisbane, Qld. 4072 (Australia)], E-mail: billc@cheque.uq.edu.au

2007-07-01T23:59:59.000Z

423

State-of-the-art review of computational fluid dynamics modeling for fluid-solids systems  

DOE Green Energy (OSTI)

As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBRS) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. Solids motion is also the key to understanding erosion processes. Erosion rates in FBRs and pneumatic and slurry components are computed by ANL`s EROSION code to predict the potential metal wastage of FBR walls, intervals, feed distributors, and cyclones. Only the FLUFIX and IRF codes will be reviewed in the paper together with highlights of the validations because of length limitations. It is envisioned that one day, these codes with user-friendly pre and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale and biomass as energy sources, to retain energy security, and to remediate waste and ecological problems.

Lyczkowski, R.W.; Bouillard, J.X.; Ding, J.; Chang, S.L. [Argonne National Lab., IL (United States); Burge, S.W. [Babcock and Wilcox, Alliance, OH (United States). Alliance Research Center

1994-05-12T23:59:59.000Z

424

Modeling the Forest or Modeling the Trees A Comparison of System Dynamics and Agent-Based Simulation  

E-Print Network (OSTI)

System Dynamics and Agent-based Simulation are two approaches that use computer simulation for investigating non-linear social and socio-economic systems with a focus on the understanding and qualitative prediction of a system’s behavior. Although the two schools have a broad overlap in research topics they have been relatively unnoticed by each other so far. This paper contributes to the cross-study of System Dynamics and Agent-Based Simulation. It uncovers and contrasts the primary conceptual predispositions underlying the two approaches. Moreover, ideas about how the approaches could be integrated are presented. Key words: System Dynamics, Agent-based Simulation

Nadine Schieritz; Peter M. Milling

2003-01-01T23:59:59.000Z

425

Integral Kramers formula for the fission rate versus dynamical modeling: The case of deformation-dependent temperature  

Science Conference Proceedings (OSTI)

We have derived approximate analytical formulas describing the quasistationary fission rate of excited nuclei (the Kramers rates). These rates are compared with those resulting from dynamical modeling using the Smoluchowski equation (the dynamical rates). Contrary to the original Kramers approach, we have accounted for the microcanonical nature of the fission process. The influence of the potential at the scission point on the fission rates is also studied. Comparison with the dynamical rates enables us to define the accuracy of the Kramers rates in the wide range of the ratio of the fission barrier height B{sub f} to the temperature at the quasistationary state T{sub c} up to 16. These high values are not reachable within the traditional Langevin approach.

Gontchar, I. I.; Kuzyakin, R. A. [Physics and Chemistry Department, Omsk State Transport University, Omsk 644046 (Russian Federation)

2011-07-15T23:59:59.000Z

426

A Spatially Distributed Model to Simulate Water, Energy, and Vegetation Dynamics Using Information from Regional Climate Models  

Science Conference Proceedings (OSTI)

Studies seeking to understand the impacts of climate variability and change on the hydrology of a region need to take into account the dynamics of vegetation and its interaction with the hydrologic and energy cycles. Yet, most of the hydrologic ...

M. P. Maneta; N. L. Silverman

2013-08-01T23:59:59.000Z

427

A spatially-distributed model to simulate water, energy and vegetation dynamics using information from regional climate models  

Science Conference Proceedings (OSTI)

Because of the strong interaction between vegetation and the terrestrial phase of the hydrologic cycle, the dynamics of vegetation needs to be taken into account in any study seeking to understand the impacts of management or changing atmospheric ...

M. P. Maneta; N. Silverman

428

Modeling and simulation of new configuration of dynamic voltage restorer for power quality improvement  

Science Conference Proceedings (OSTI)

The dynamic voltage restorer (DVR) is a custom device that is used to maintain the voltage at the load terminals from various power quality problems from a disturbed incoming supply. In this paper, a novel control strategy is described for mitigation ... Keywords: custom device, dynamic voltage restorer (DVR), power quality, sags, sensitive loads, swells

Rosli Omar; Nasrudin Abdul Rahim

2011-04-01T23:59:59.000Z

429

Development of a sub-scale dynamics model for pressure relaxation of multi-material cells in Lagrangian hydrodynamics  

SciTech Connect

We have extended the Sub-Scale Dynamics (SSD) closure model for multi-fluid computational cells. Volume exchange between two materials is based on the interface area and a notional interface translation velocity, which is derived from a linearized Riemann solution. We have extended the model to cells with any number of materials, computing pressure-difference-driven volume and energy exchange as the algebraic sum of pairwise interactions. In multiple dimensions, we rely on interface reconstruction to provide interface areas and orientations, and centroids of material polygons. In order to prevent unphysically large or unmanageably small material volumes, we have used a flux-corrected transport (FCT) approach to limit the pressure-driven part of the volume exchange. We describe the implementation of this model in two dimensions in the FLAG hydrodynamics code. We also report on Lagrangian test calculations, comparing them with others made using a mixed-zone closure model due to Tipton, and with corresponding calculations made with only single-material cells. We find that in some cases, the SSD model more accurately predicts the state of material in mixed cells. By comparing the algebraic forms of both models, we identify similar dependencies on state and dynamical variables, and propose explanations for the apparent higher fidelity of the SSD model.

Harrison, Alan K [Los Alamos National Laboratory; Shashkov, Mikhail J [Los Alamos National Laboratory; Fung, Jimmy [Los Alamos National Laboratory; Canfield, Thomas R [Los Alamos National Laboratory; Kamm, James R [SNLA

2010-10-14T23:59:59.000Z

430

A localised subgrid scale model for fluid dynamical simulations in astrophysics II: Application to type Ia supernovae  

E-Print Network (OSTI)

The dynamics of the explosive burning process is highly sensitive to the flame speed model in numerical simulations of type Ia supernovae. Based upon the hypothesis that the effective flame speed is determined by the unresolved turbulent velocity fluctuations, we employ a new subgrid scale model which includes a localised treatment of the energy transfer through the turbulence cascade in combination with semi-statistical closures for the dissipation and non-local transport of turbulence energy. In addition, subgrid scale buoyancy effects are included. In the limit of negligible energy transfer and transport, the dynamical model reduces to the Sharp-Wheeler relation. According to our findings, the Sharp-Wheeler relation is insuffcient to account for the complicated turbulent dynamics of flames in thermonuclear supernovae. The application of a co-moving grid technique enables us to achieve very high spatial resolution in the burning region. Turbulence is produced mostly at the flame surface and in the interior ash regions. Consequently, there is a pronounced anisotropy in the vicinity of the flame fronts. The localised subgrid scale model predicts significantly enhanced energy generation and less unburnt carbon and oxygen at low velocities compared to earlier simulations.

W. Schmidt; J. C. Niemeyer; W. Hillebrandt; F. K. Roepke

2006-01-23T23:59:59.000Z

431

Self-consistent modeling of the dynamic evolution of magnetic island growth in the presence of stabilizing ECCD  

E-Print Network (OSTI)

The most promising technique for the control of neoclassical tearing modes in tokamak experiments is the compensation of the missing bootstrap current with electron-cyclotron current drive. In this frame, the dynamics of magnetic islands has been studied extensively in terms of the modified Rutherford equation, including the presence of current drive, either analytically described or computed by numerical methods. In this article, a self-consistent model for the dynamic evolution of the magnetic island and the driven current is derived, which takes into account the island's magnetic topology and its effect on the current drive. The model combines the modified Rutherford equation with a ray-tracing approach to electron-cyclotron wave propagation and absorption. Numerical results exhibit a decrease in the time required for complete stabilization with respect to the conventional computation (not taking into account the island geometry), which increases with increasing initial island size and radial misalignment ...

Chatziantonaki, Ioanna; Isliker, Heinz; Vlahos, Loukas

2013-01-01T23:59:59.000Z

432

Application of the Dynamic Mercury Cycling Model (D-MCM) to the Robert C. Byrd Pool, Ohio River  

Science Conference Proceedings (OSTI)

This Technical Update describes the ongoing application of the Electric Power Research Institute’s (EPRI’s) Dynamic Mercury Cycling Model (D-MCM) to the Ohio River. The study focuses on mercury sources, sinks and bioaccumulation in the Robert C. Byrd Pool in the Ohio River, including the contribution of nearby coal-fired facilities to fish mercury (Hg) concentrations.BackgroundMonitoring of Hg concentrations in sport fish in the Ohio River has shown generally low ...

2012-12-12T23:59:59.000Z

433

Extreme Events and the General Circulation: Observations and Stochastic Model Dynamics  

Science Conference Proceedings (OSTI)

This study explores the dynamical role of non-Gaussian potential vorticity variability (extreme events) in the zonally averaged circulation of the atmosphere within a stochastic framework. First the zonally averaged skewness and kurtosis patterns ...

Philip Sura; Maxime Perron

2010-09-01T23:59:59.000Z

434

Low Temperature Static and Dynamic Behavior of the Two-Dimensional Easy Axis Heisenberg Model  

E-Print Network (OSTI)

´isica, ICEx, Universidade Federal de Minas Gerais Belo Horizonte, CP 702, CEP 30123-970, MG, Brazil (August 10, are compared to numerical simulation data combining cluster-Monte Carlo algorithms and Spin Dynamics

Wysin, Gary

435

A Multimoment Constrained Finite-Volume Model for Nonhydrostatic Atmospheric Dynamics  

Science Conference Proceedings (OSTI)

The two-dimensional nonhydrostatic compressible dynamical core for the atmosphere has been developed by using a new nodal-type high-order conservative method, the so-called multimoment constrained finite-volume (MCV) method. Different from the ...

Xingliang Li; Chungang Chen; Xueshun Shen; Feng Xiao

2013-04-01T23:59:59.000Z

436

Flowness + FlowBlocks : uncovering the dynamics of everyday life through playful modeling  

E-Print Network (OSTI)

It is not easy to understand the dynamics underlying everyday life. The change around us is so ubiquitous; the processes governing change are invisible; the relationships between cause & effect are usually disconnected in ...

Zuckerman, Oren, 1970-

2007-01-01T23:59:59.000Z

437

Computational fluid dynamics modelling and experimental study on a single silica gel type B  

Science Conference Proceedings (OSTI)

The application of computational fluid dynamics (CFDs) in the area of porous media and adsorption cooling system is becoming more practical due to the significant improvement in computer power. The results from previous studies have shown that CFD can ...

John White

2012-01-01T23:59:59.000Z

438

A sniffer technique for an efficient deduction of model dynamical equations using genetic programming  

Science Conference Proceedings (OSTI)

A novel heuristic technique that enhances the search facility of the standard genetic programming (GP) algorithm is presented. The method provides a dynamic sniffing facility to optimize the local search in the vicinity of the current best chromosomes ...

Dilip P. Ahalpara; Abhijit Sen

2011-04-01T23:59:59.000Z

439

A Scalable Spectral Element Eulerian Atmospheric Model (SEE-AM) for NWP: Dynamical Core Tests  

Science Conference Proceedings (OSTI)

A new dynamical core for numerical weather prediction (NWP) based on the spectral element method is presented. This paper represents a departure from previously published work on solving the atmospheric primitive equations in that the horizontal ...

Francis X. Giraldo; Thomas E. Rosmond

2004-01-01T23:59:59.000Z

440

Modeling the resource consumption of Housing in New Orleans using System Dynamics  

E-Print Network (OSTI)

This work uses Systems Dynamics as a methodology to analyze the resource requirements of New Orleans as it recovers from Hurricane Katrina. It examines the behavior of the city as a system of stocks, flows and time delays ...

Quinn, David James, Ph. D. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

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441

Dynamic and Thermodynamic Influences of the Tibetan Plateau on the Atmosphere in a General Circulation Model  

Science Conference Proceedings (OSTI)

The dynamic and thermodynamic influences of the Tibetan Plateau on the temperature geopotential height, horizontal wind, vertical velocity, cloud and precipitation patterns over eastern Asia am physically investigated employing a general ...

Qinglin Zheng; Kuo-Nan Liou

1986-07-01T23:59:59.000Z

442

Incorporating endogenous demand dynamics into long-term capacity expansion power system models for Developing countries  

E-Print Network (OSTI)

This research develops a novel approach to long-term power system capacity expansion planning for developing countries by incorporating endogenous demand dynamics resulting from social processes of technology adoption. ...

Jordan, Rhonda LeNai

2013-01-01T23:59:59.000Z

443

Multi-resolution Modeling of the Dynamic Loading of Metal Matrix ...  

Science Conference Proceedings (OSTI)

Ab Initio Local Energy and Local Stress Calculations: Applications to Materials ... Computational Fluid Dynamics and Experimental Results for the Horizontal .... Films and Applications to a New Generation of Multifunctional Devices/Systems.

444

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

445

Application of Continuous Dynamic Grid Adaption Techniques to Meteorological Modeling. Part II: Efficiency  

Science Conference Proceedings (OSTI)

The continuous dynamic adaptive grid (CDGA) technique has been shown to yield significant improvements in solution accuracy over equivalent fixed-grid methods. In this paper we consider the related question of efficiency; for a given degree of ...

Gary S. Dietachmayer

1992-08-01T23:59:59.000Z

446

A Relationship between Energy and Angular Momentum Conservation in Dynamical Models  

Science Conference Proceedings (OSTI)

In Newtonian particle dynamics the covariance of the kinetic energy equation to transformation between different inertial frames may he demonstrated only if the correct momentum equation is applied. A similar relation exists between the angular ...

A. A. White

1989-06-01T23:59:59.000Z

447

Characterization of structural properties and dynamic behavior using distributed accelerometer networks and numerical modeling  

E-Print Network (OSTI)

Both vibration-based structural health monitoring methodologies and seismic performance analysis rely on estimates of the base-line dynamic behavior of a structure. A common method for making this estimate is through ...

Trocha, Peter Adam

2013-01-01T23:59:59.000Z

448

Global Modeling of Land Water and Energy Balances. Part I: The Land Dynamics (LaD) Model  

Science Conference Proceedings (OSTI)

A simple model of large-scale land (continental) water and energy balances is presented. The model is an extension of an earlier scheme with a record of successful application in climate modeling. The most important changes from the original ...

P. C. D. Milly; A. B. Shmakin

2002-06-01T23:59:59.000Z

449

Experiment selection for the discrimination of semi-quantitative models of dynamical systems  

Science Conference Proceedings (OSTI)

Modeling an experimental system often results in a number of alternative models that are all justified by the available experimental data. To discriminate among these models, additional experiments are needed. Existing methods for the selection of discriminatory ... Keywords: Computer-supported modeling, Information theory, Model discrimination, Population biology, Qualitative and semi-quantitative modeling and simulation

Ivayla Vatcheva; Hidde de Jong; Olivier Bernard; Nicolaas J. I. Mars

2006-04-01T23:59:59.000Z

450

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

451

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

452

Damped Ly-alpha Systems in Semi-Analytic Models: Sensitivity to dynamics, disk properties, and cosmology  

E-Print Network (OSTI)

Previously we have shown that it is possible to account for the kinematic properties of damped Lyman alpha systems (DLAS) in the context of semi-analytic models. In these models, hierarchical structure formation is approximated by constructing a merger tree for each dark matter halo. A natural consequence is that every virialized halo may contain not only a central galaxy, but also a number of satellite galaxies as determined by its merging history. Thus the kinematics of the DLAS arise from the combined effects of the internal rotation of gas disks and the motions between gas disks within a common halo. Here we investigate the sensitivity of this model to some of the assumptions made previously, including the modeling of satellite dynamics, the scale height of the gas, and the cosmology.

Ariyeh H. Maller; Rachel S. Somerville; Jason X. Prochaska; Joel R. Primack

2000-02-24T23:59:59.000Z

453

Border Crossing Modeling and Analysis: A Non-Stationary Dynamic Reallocation Methodology For Terminating Queueing Systems  

E-Print Network (OSTI)

The United States international land boundary is a volatile, security intense area. In 2010, the combined trade was $918 billion within North American nations, with 80% transported by commercial trucks. Over 50 million commercial vehicles cross the Texas/Mexico border every year, not including private vehicles and pedestrian traffic, between Brownsville and El Paso, Texas, through one of over 25 major border crossings called "ports of entry" (POE). Recently, securing our southwest border from terrorist interventions, undocumented immigrants, and the illegal flow of drugs and guns has dominated the need to efficiently and effectively process people, goods and traffic. Increasing security and inspection requirements are seriously affecting transit times. Each POE is configured as a multi-commodity, prioritized queueing network which rarely, if ever, operates in steady-state. Therefore, the problem is about finding a balance between a reduction of wait time and its variance, POE operation costs, and the sustainment of a security level. The contribution of the dissertation is three-fold. The first uses queueing theory on the border crossing process to develop a methodology that decreases border wait times without increasing costs or affecting security procedures. The outcome is the development of the Dynamic Reallocation Methodology (DRM). Currently at the POE, inspection stations are fixed and can only inspect one truck type, FAST or Non-FAST program participant. The methodology proposes moveable servers that once a threshold is met, can be switched to service the other type of truck. Particular emphasis is given to inspection (service) times under time-varying arrivals (demands). The second contribution is an analytical model of the POE, to analyze the effects of the DRM. First assuming a Markovian service time, DRM benefits are evaluated. However, field data and other research suggest a general distribution for service time. Therefore, a Coxian k-phased approximation is implemented. The DRM is analyzed under this new baseline using expected number in the system, and cycle times. A variance reduction procedure is also proposed and evaluated under DRM. Results show that queue length and wait time is reduced 10 to 33% depending on load, while increasing FAST wait time by less than three minutes.

Moya, Hiram

2012-08-01T23:59:59.000Z

454

overview of ‘Mathematical Models of Collective Dynamics in Biology and Evolution ’ (University of  

E-Print Network (OSTI)

Indeed, when? Solution to this apparent paradox is amazingly simple, provided we do not interpret the problem straightforwardly. Take one female and one male individual of any animal species, keep them together for a sufficiently long time, feed them properly and then after a while you will normally get more than two of them. Otherwise, keep them far away from each other or do not feed them well enough and you will obtain zero at the end. The above example may look somewhat like an anecdote but it is, in fact, quite serious. As a matter of fact, it grasps the essence of the population dynamics and very much that of collective dynamics in general: once the interaction between subsystems becomes strong enough, a new entity may emerge. It emphasizes the importance of different temporal and spatial scales and also stresses the principal difference between the dynamics of closed and open systems. Once the system is open to influxes of mass, energy and information, one plus one is not necessarily two any more. Collective dynamics—understood as the dynamics arising from the interplay between the constituting elementary argents or parts of a more complex system—has been one of the main paradigms of the natural sciences over the last several decades. Interactions between the argents are often non-linear and therefore it also greatly fertilized mathematical development, in particular, in the areas such as nonlinear

Alexander Gorban; Sergei Petrovskii

2010-01-01T23:59:59.000Z

455

Drum-boiler dynamics  

Science Conference Proceedings (OSTI)

A nonlinear dynamic model for natural circulation drum-boilers is presented. The model describes the complicated dynamics of the drum, downcomer, and riser components. It is derived from first principles, and is characterized by a few physical parameters. ...

K. J. íStröM; R. D. Bell

2000-03-01T23:59:59.000Z

456

A Generalized Energy Balance Climate Model with Parameterized Dynamics and Diabatic Heating  

Science Conference Proceedings (OSTI)

Energy balance models have proven useful in understanding mechanisms and feedbacks in the climate system. An original global energy balance model is presented here. The model is solved numerically for equilibrium climate states defined by zonal ...

Karen M. Shell; Richard C. J. Somerville

2005-06-01T23:59:59.000Z

457

Vegetation Dynamics Enhancing Long-Term Climate Variability Confirmed by Two Models  

Science Conference Proceedings (OSTI)

Two different coupled climate–vegetation models, the Community Climate Model version 3 coupled to the Integrated Biosphere Simulator (CCM3–IBIS) and the Laboratoire de Météorologie Dynamique’s climate model coupled to the Organizing Carbon and ...

Christine Delire; Nathalie de Noblet-Ducoudré; Adriana Sima; Isabelle Gouirand

2011-05-01T23:59:59.000Z

458

Organizational ecology and population dynamics in politics : an agent-based model  

E-Print Network (OSTI)

2.3.3 Using an Agent-Based Model . . . . .Chapter 3 An Agent Based Model of Organizational Ecology 3.1of cooperation: Agent-based models of competition and

Jung, Danielle Fitzpatrick

2012-01-01T23:59:59.000Z

459

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

460

Progressive Dynamical Drive Train Modeling as Part of NREL Gearbox Reliability Collaborative: Preprint  

DOE Green Energy (OSTI)

The Gearbox Reliabiity Collaborative seeks to integrate several numerical models into the wind turbine drive train design process. This paper describes these models.

Oyague, F.

2008-07-01T23:59:59.000Z

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