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Note: This page contains sample records for the topic "modeling transition dynamics" from the National Library of EnergyBeta (NLEBeta).
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1

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

2

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

3

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

4

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

5

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

6

Using System Dynamics to Model the Transition to Biofuels in the United States: Preprint  

DOE Green Energy (OSTI)

Transitioning to a biofuels industry that is expected to displace about 30% of current U.S. gasoline consumption requires a robust biomass-to-biofuels system-of-systems that operates in concert with the existing markets. This paper discusses employing a system dynamics approach to investigate potential market penetration scenarios for cellulosic ethanol and to help government decision makers focus on areas with greatest potential.

Bush, B.; Duffy, M.; Sandor, D.; Peterson, S.

2008-06-01T23:59:59.000Z

7

Dynamics of a Quantum Phase Transition  

E-Print Network (OSTI)

We present two approaches to the dynamics of a quench-induced phase transition in quantum Ising model. The first one retraces steps of the standard approach to thermodynamic second order phase transitions in the quantum setting. The second one is purely quantum, based on the Landau-Zener formula for transition probabilities in avoided level crossings. We show that the two approaches yield compatible results for the scaling of the defect density with the quench rate. We exhibit similarities between them, and comment on the insights they give into dynamics of quantum phase transitions.

Wojciech H. Zurek; Uwe Dorner; Peter Zoller

2005-03-21T23:59:59.000Z

8

Using System Dynamics to Model the Transition to Biofuels in the United States  

DOE Green Energy (OSTI)

Today, the U.S. consumes almost 21 million barrels of crude oil per day; approximately 60% of the U.S. demand is supplied by imports. The transportation sector alone accounts for two-thirds of U.S. petroleum use. Biofuels, liquid fuels produced from domestically-grown biomass, have the potential to displace about 30% of current U.S. gasoline consumption. Transitioning to a biofuels industry on this scale will require the creation of a robust biomass-to-biofuels system-of-systems that operates in concert with the existing agriculture, forestry, energy, and transportation markets. The U.S. Department of Energy is employing a system dynamics approach to investigate potential market penetration scenarios for cellulosic ethanol, and to aid decision makers in focusing government actions on the areas with greatest potential to accelerate the deployment of biofuels and ultimately reduce the nationpsilas dependence on imported oil.

Bush, B.; Duffy, M.; Sandor, D.; Peterson, S.

2008-01-01T23:59:59.000Z

9

Dynamic Phase Transitions in Coupled Motor Proteins  

E-Print Network (OSTI)

The effect of interactions on dynamics of coupled motor proteins is investigated theoretically. A simple stochastic discrete model, that allows to calculate explicitly the dynamic properties of the system, is developed. It is shown that there are two dynamic regimes, depending on the interaction between the particles. For strong interactions the motor proteins move as one tight cluster, while for weak interactions there is no correlation in the motion of the proteins, and the particle separation increases steadily with time. The boundary between two dynamic phases is specified by a critical interaction that has a non-zero value only for the coupling of the asymmetric motor proteins, and it depends on the temperature and the transitions rates. At the critical interaction there is a change in a slope for the mean velocities and a discontinuity in the dispersions of the motor proteins as a function of the interaction energy.

Evgeny B. Stukalin; Anatoly B. Kolomeisky

2005-09-16T23:59:59.000Z

10

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

11

Managing the transition toward self-sustaining alternative fuel vehicle markets : policy analysis using a dynamic behavioral spatial model  

E-Print Network (OSTI)

Designing public policy or industry strategy to bolster the transition to alternative fuel vehicles (AFVs) is a formidable challenge as demonstrated by historical failed attempts. The transition to new fuels occurs within ...

Supple, Derek R. (Derek Richard)

2007-01-01T23:59:59.000Z

12

FCCU transition-probability model  

Science Conference Proceedings (OSTI)

The adequacy of the use of transition-probability matrices for modelling fluidised catalyst cracker unit emissions was investigated. A number of different-sized matrices that modelled the processes of attrition and agglomeration were used, and it was ... Keywords: Agglomeration, Attrition, Probability matrix

Robbie J. Dixon; Maki Matsuka; Roger D. Braddock; Josh M. Whitcombe; Igor E. Agranovski

2007-02-01T23:59:59.000Z

13

The Dynamic Transition of Protein Hydration Water  

E-Print Network (OSTI)

Thin layers of water on biomolecular and other nanostructured surfaces can be supercooled to temperatures not accessible with bulk water. Chen et al. [PNAS 103, 9012 (2006)] suggested that anomalies near 220 K observed by quasi-elastic neutron scattering can be explained by a hidden critical point of bulk water. Based on more sensitive measurements of water on perdeuterated phycocyanin, using the new neutron backscattering spectrometer SPHERES, and an improved data analysis, we present results that show no sign of such a fragile-to-strong transition. The inflection of the elastic intensity at 220 K has a dynamic origin that is compatible with a calorimetric glass transition at 170 K. The temperature dependence of the relaxation times is highly sensitive to data evaluation; it can be brought into perfect agreement with the results of other techniques, without any anomaly.

W. Doster; S. Busch; A. M. Gaspar; M. -S. Appavou; J. Wuttke; H. Scheer

2009-11-26T23:59:59.000Z

14

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.

15

Modelling societal transitions with agent transformation  

Science Conference Proceedings (OSTI)

Transition models explain long-term and large-scale processes fundamentally changing the structure of a societal system. Our concern is that most transition models are too static. Although they capture a move of focus from static equilibria to transitions ... Keywords: Agent-based modelling, Integrated sustainability assessment, Societal transitions

Michel Schilperoord; Jan Rotmans; Noam Bergman

2008-12-01T23:59:59.000Z

16

Dynamic Phase Transitions In The Spin-2 Ising System Under An Oscillating Magnetic Field Within The Effective-Field Theory  

SciTech Connect

The dynamic phase transitions are studied in the spin-2 Ising model under a time-dependent oscillating magnetic field by using the effective-field theory with correlations. The effective-field dynamic equation is derived by employing the Glauber transition rates and the phases in the system are obtained by solving this dynamic equation. The nature (first- or second-order) of the dynamic phase transition is characterized by investigating the thermal behavior of the dynamic order parameter and the dynamic phase transition temperatures are obtained. The dynamic phase diagrams are presented in (T/zJ, h/zJ) plane.

Ertas, Mehmet; Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Deviren, Bayram [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey)

2010-12-23T23:59:59.000Z

17

Dynamic Transition Theory and its Application to Gas-Liquid Phase Transitions  

E-Print Network (OSTI)

Dynamic Transition Theory and its Application to Gas-Liquid Phase Transitions Tian Ma, Shouhong close links to the physics. In return the theory is applied to the physical problems. 2 #12;liquid gas #12;Objective: To study the types and the mechanisms of liquid-gas transitions. The phases correspond

Wang, Shouhong

18

Agent-Based Modeling and Simulation for Hydrogen Transition Analysis  

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

Agent Agent Agent - - Based Modeling Based Modeling and Simulation (ABMS) and Simulation (ABMS) for Hydrogen Transition for Hydrogen Transition Analysis Analysis Marianne Mintz Hydrogen Transition Analysis Workshop US Department of Energy January 26, 2006 Objectives and Scope for Phase 1 2 Analyze the hydrogen infrastructure development as a complex adaptive system using an agent-based modeling and simulation (ABMS) approach Develop an ABMS model to simulate the evolution of that system, spanning the entire H2 supply chain from production to consumption Identify key factors that either promote or inhibit the growth of H2 infrastructure Apply ABMS to get new insights into transition, particularly early transition phase - Dynamic interplay between supply and demand

19

Energy Transition Model | Open Energy Information  

Open Energy Info (EERE)

Energy Transition Model Energy Transition Model Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Energy Transition Model Agency/Company /Organization: Quintel Intelligence Sector: Energy Topics: Resource assessment Resource Type: Maps, Software/modeling tools User Interface: Website Website: energytransitionmodel.com/ Country: Netherlands Web Application Link: energytransitionmodel.com/ Cost: Free OpenEI Keyword(s): International UN Region: Western Europe References: webservice-energy.org[1] MINES Energy Transition Model[2] Logo: Energy Transition Model The Energy Transition Model is an independent, comprehensive and fact-based energy model that is used by governments, corporations, NGOs and educators in various countries. It is backed by more than 20 partners. There are

20

Molecular Dynamics of Martenstic Phase Transitions  

Science Conference Proceedings (OSTI)

Presentation Title, Kinetics of martensitic phase transformation: Molecular Dynamics of Martenstic ... A Comparison of Coulombic and Plastic Shear Faults in Ice.

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Modelling Accretion in Transitional Disks  

E-Print Network (OSTI)

Transitional disks are protoplanetary disk around young stars that display inner holes in the dust distribution within a few AU, which is accompanied nevertheless by some gas accretion onto the central star. These cavities could possibly be created by the presence of one or more massive planets. If the gap is created by planets and gas is still present in it, then there should be a flow of gas past the planet into the inner region. It is our goal to study the mass accretion rate into the gap and in particular the dependency on the planet's mass and the thermodynamic properties of the disk. We performed 2D hydro simulations for disks with embedded planets. We added radiative cooling from the disk surfaces, radiative diffusion in the disk midplane, and stellar irradiation to the energy equation to have more realistic models. The mass flow rate into the gap region depends, for given disk thermodynamics, non-monotonically on the mass of the planet. Generally, more massive planets open wider and deeper gaps which ...

Müller, Tobias W A

2013-01-01T23:59:59.000Z

22

Dynamics in the Metabasin Space of a Lennard-Jones Glass Former: Connectivity and Transition Rates  

E-Print Network (OSTI)

Using simulations, we construct the effective dynamics in metabasin space for a Lennard-Jones glass-former. Metabasins are identified via a scheme that measures transition rates between inherent structures, and generates clusters of inherent structures by drawing in branches that have the largest transition rates. The effective dynamics is shown to be Markovian but differs significantly from the simplest trap models. We specifically show that retaining information about the connectivity in metabasin space is crucial for reproducing the slow dynamics observed in this system.

Yasheng Yang; Bulbul Chakraborty

2008-10-14T23:59:59.000Z

23

Towards Integrated Verification of Timed Transition Models  

Science Conference Proceedings (OSTI)

This paper describes an attempt to combine theorem proving and model-checking to formally verify real-time systems in a discrete time setting. The Timed Automata Modeling Environment (TAME) has been modified to provide a formal model for Time Transition ... Keywords: PVS, Real-time, SAL, equivalence verification, model reduction, model-checking, theorem proving

Mark Lawford; Vera Pantelic; Hong Zhang

2006-04-01T23:59:59.000Z

24

The Dynamics of Air Transportation System Transition  

E-Print Network (OSTI)

Both U.S. and European Air Transportation Systems face substantial challenges in transforming to meet future demand. This paper uses a feedback model to identify

Mozdzanowska, Aleksandra

25

HyPro: Modeling the Hydrogen Transition  

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

and exercise it to determine the key drivers of the hydrogen transition. 2005 Develop a production database from H2A and an economic cost model to determine and compare...

26

Vehicle Modeling and Verification of CNG-Powered Transit Buses  

E-Print Network (OSTI)

Modeling and Verification of CNG-Powered Transit BusesModeling and Verification of CNG-Powered Transit Buses.Modeling and Veri?cation of CNG-Powered Transit Buses J.K.

Hedrick, J. K.; Ni, A.

2004-01-01T23:59:59.000Z

27

Page 1 Session 7: Material Phase Transition, Modeling, and Other  

National Nuclear Security Administration (NNSA)

7: Material Phase Transition, Modeling, and Other 7: Material Phase Transition, Modeling, and Other Thermodynamically Consistent Method for Calculation of Free Energy and Equilibrium Curves of First-Order Phase Transitions in Classical Molecular Dynamics *A.V. Karavaev andV.V. Dremov Russian Federal Nuclear Centre - Zababakhin Institute of Technical Physics, Snezhinsk, Russia State-of-the-art parallel computers allow performing MD simulations not only with substantial number of particles, but also using of complicated computationally intense many-body potentials of the interatomic interactions. One of the most important tasks for the computer-aided material science is accurate and extensive characterization of thermodynamic properties of the materials. An essential part of this characterization is the prediction of phase

28

Transitional solar dynamics, cosmic rays and global warming  

E-Print Network (OSTI)

Solar activity is studied using a cluster analysis of the time-fluctuations of the sunspot number. It is shown that in an Historic period the high activity components of the solar cycles exhibit strong clustering, whereas in a Modern period (last seven solar cycles: 1933-2007) they exhibit a white-noise (non-)clustering behavior. Using this observation it is shown that in the Historic period, emergence of the sunspots in the solar photosphere was strongly dominated by turbulent photospheric convection. In the Modern period, this domination was broken by a new more active dynamics of the inner layers of the convection zone. Then, it is shown that the dramatic change of the sun dynamics at the transitional period (between the Historic and Modern periods, solar cycle 1933-1944yy) had a clear detectable impact on Earth climate. A scenario of a chain of transitions in the solar convective zone is suggested in order to explain the observations, and a forecast for the global warming is suggested on the basis of this scenario. A relation between the recent transitions and solar long-period chaotic dynamics has been found. Contribution of the galactic turbulence (due to galactic cosmic rays) has been discussed. These results are also considered in a content of chaotic climate dynamics at millennial timescales.

A. Bershadskii

2008-05-14T23:59:59.000Z

29

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

30

Nuclear liquid-gas phase transition studied with antisymmetrized molecular dynamics  

E-Print Network (OSTI)

The nuclear liquid-gas phase transition of the system in ideal thermal equilibrium is studied with antisymmetrized molecular dynamics. The time evolution of a many-nucleon system confined in a container is solved for a long time to get a microcanonical ensemble of a given energy and volume. The temperature and the pressure are extracted from this ensemble and the caloric curves are constructed. The present work is the first time that a microscopic dynamical model which describes nuclear multifragmentation reactions well is directly applied to get the nuclear caloric curve. The obtained constant pressure caloric curves clearly show the characteristic feature of the liquid-gas phase transition, namely negative heat capacity (backbending), which is expected for the phase transition in finite systems.

Takuya Furuta; Akira Ono

2003-05-19T23:59:59.000Z

31

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

32

How glassy are orientational dynamics of rodlike molecules near the isotropic-nematic transition?  

E-Print Network (OSTI)

In an attempt to quantitatively characterize the recently observed slow dynamics in the isotropic and nematic phase of liquid crystals, we investigate the single-particle orientational dynamics of rodlike molecules across the isotropic-nematic transition in computer simulations of a family of model systems of thermotropic liquid crystals. Several remarkable features of glassy dynamics are on display including non-exponential relaxation, dynamical heterogeneity, and non-Arrhenius temperature dependence of the orientational relaxation time. In order to obtain a quantitative measure of glassy dynamics in line with the estbalished methods in supercooled liquids, we construct a relaxation time versus scaled inverse temperature plot, and demonstrate that one can indeed define a 'fragility index' for thermotropic liquid crystals, that depends on density and aspect ratio. The values of the fragility parameter are surprisingly in the range one observed for glass forming liquids. A plausible correlation between the energy landscape features and the observed fragility is discussed.

Biman Jana; Dwaipayan Chakrabarti; Biman Bagchi

2007-03-06T23:59:59.000Z

33

GENERATION OF TRANSITION CLASS MODELS FROM FORMAL QUEUEING NETWORK DESCRIPTIONS  

E-Print Network (OSTI)

for service. The state is changed accordingly. The service rate, the number of queues, and transition probabil probabilities and the transition rates or the transition probabilities (Markov reward mod- els). The holding is a translator into transition class models. The expressive power of the method is indicated. TRANSITION CLASSES

Strelen, Christoph

34

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

35

Liquid-gas phase transition in finite nuclei within Fermionic Molecular Dynamics  

E-Print Network (OSTI)

Within Fermionic Molecular Dynamics (FMD) a quantal nuclear system with only 16 nucleons shows a clearly visible liquid-gas phase transition. The FMD model is an approximation to the many-body problem which describes the system by antisymmetrized many-body states in which each nucleon is occupying a Gaussian shaped time-dependent wave-packet. The statistical ensemble is obtained by time averaging.

H. Feldmeier; J. Schnack

1998-06-02T23:59:59.000Z

36

Transition Events in Butane Simulations: Similarities Across Models  

E-Print Network (OSTI)

From a variety of long simulations of all-atom butane using both stochastic and fully-solved molecular dynamics, we have uncovered striking generic behavior which also occurs in one-dimensional systems. We find an apparently universal distribution of transition event durations, as well as a characteristic speed profile along the reaction coordinate. An approximate analytic distribution of event durations, derived from a one-dimensional model, correctly predicts the asymptotic behavior of the universal distribution for both short and long durations. 1 1

Daniel M. Zuckerman; Thomas B. Woolf

2008-01-01T23:59:59.000Z

37

Transition Events in Butane Simulations Similarities Across Models  

E-Print Network (OSTI)

From a variety of long simulations of all-atom butane using both stochastic and fully-solved molecular dynamics, we have uncovered striking generic behavior which also occurs in one-dimensional systems. We find an apparently universal distribution of transition event durations, as well as a characteristic speed profile along the reaction coordinate. An approximate analytic distribution of event durations, derived from a one-dimensional model, correctly predicts the asymptotic behavior of the universal distribution for both short and long durations.

Zuckerman, D M; Zuckerman, Daniel M.; Woolf, Thomas B.

2001-01-01T23:59:59.000Z

38

Dynamics of Conformational Transition in Thermo-Sensitive Polymers and  

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

Atomistic simulations elucidating the coil-to-globule conformational changes in thermosensitive polymers. Atomistic simulations elucidating the coil-to-globule conformational changes in thermosensitive polymers. Atomistic simulations elucidating the coil-to-globule conformational changes in thermosensitive polymers. Dynamics of Conformational Transition in Thermo-Sensitive Polymers and Hydrogels PI Name: Subramanian Sankaranarayanan PI Email: skrssank@anl.gov Institution: Argonne National Laboratory Allocation Program: ALCC Allocation Hours at ALCF: 50 Million Year: 2012 Research Domain: Materials Science Subramanian Sankaranarayanan with Argonne's Center for Nanoscale Materials was awarded 50 million hours to study conformational transformations in thermo-sensitive oligomers and their macroscopic architectures such as polymer brushers and polymer gels. Understanding the conformational transformations of isolated linear polymer

39

Abrupt Transitions and Hysteresis in Thermohaline Laboratory Models  

Science Conference Proceedings (OSTI)

As a driving parameter is slowly altered, thermohaline ocean circulation models show either a smooth evolution of a mode of flow or an abrupt transition of temperature and salinity fields from one mode to another. An abrupt transition might occur ...

J. A. Whitehead

2009-05-01T23:59:59.000Z

40

A Stochastic Model for the Transition to Strong Convection  

Science Conference Proceedings (OSTI)

A simple stochastic model is designed and analyzed in order to further understand the transition to strong convection. The transition has been characterized recently in observational data by an array of statistical measures, including (i) a sharp ...

Samuel N. Stechmann; J. David Neelin

2011-12-01T23:59:59.000Z

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


41

Dynamic 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

42

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

Open Energy Info (EERE)

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

43

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

Open Energy Info (EERE)

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

44

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

45

Variational description of Gibbs-non-Gibbs dynamical transitions for spin-flip systems with a Kac-type interaction  

E-Print Network (OSTI)

We continue our study of Gibbs-non-Gibbs dynamical transitions. In the present paper we consider a system of Ising spins on a large discrete torus with a Kac-type interaction subject to an independent spin-flip dynamics (infinite-temperature Glauber dynamics). We show that, in accordance with the program outlined in \\cite{vEFedHoRe10}, in the thermodynamic limit Gibbs-non-Gibbs dynamical transitions are \\emph{equivalent} to bifurcations in the set of global minima of the large-deviation rate function for the trajectories of the empirical density \\emph{conditional} on their endpoint. More precisely, the time-evolved measure is non-Gibbs if and only if this set is not a singleton for \\emph{some} value of the endpoint. A partial description of the possible scenarios of bifurcation is given, leading to a characterization of passages from Gibbs to non-Gibbs and vice versa, with sharp transition times. Our analysis provides a conceptual step-up from our earlier work on Gibbs-non-Gibbs dynamical transitions for the Curie-Weiss model, where the mean-field interaction allowed us to focus on trajectories of the empirical magnetization rather than the empirical density.

Roberto Fernández; Frank den Hollander; Julián Martínez

2013-09-14T23:59:59.000Z

46

Transition events in butane simulations: Similarities across models Daniel M. Zuckermana)  

E-Print Network (OSTI)

Transition events in butane simulations: Similarities across models Daniel M. Zuckermana of long simulations of all-atom butane using both stochastic and fully solved molecular dynamics, we have behavior in molecular simulations has long been a topic of interest, and butane has been an important test

Zuckerman, Daniel M.

47

Liquid-gas phase transition in hot nuclei: correlation between dynamical and thermodynamical signals  

E-Print Network (OSTI)

The dynamics and thermodynamics of phase transition in hot nuclei are studied through experimental results on multifragmentation of heavy systems (A$geq$200) formed in central heavy ion collisions. Different signals indicative of a phase transition studied in the INDRA collaboration are presented and their consistency is stressed.

M. F. Rivet; B. Borderie; R. Bougault; P. Désesquelles; E. Galichet; B. Guiot; N. Le Neindre; M. Parlog; G. Tabacaru; J. P. Wieleczko; the INDRA Collaboration

2005-01-12T23:59:59.000Z

48

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

49

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

50

Prethermalization and dynamical transition in an isolated trapped ion spin chain  

E-Print Network (OSTI)

We propose an experimental scheme to observe prethermalization and dynamical transition in one-dimensional XY spin chain with long range interaction and inhomogeneous lattice spacing, which can be readily implemented with the recently developed trapped-ion quantum simulator. Local physical observables are found to relax to prethermal values at intermediate time scale, followed by complete relaxation to thermal values at much longer time. The physical origin of prethermalization is explained by spotting a non-trivial structure in lower half of the energy spectrum. The dynamical behavior of the system is shown to cross difference phases when the interaction range is continuously tuned, indicating the existence of dynamical phase transition.

Zhe-Xuan Gong; L. -M. Duan

2013-05-05T23:59:59.000Z

51

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

52

Detection of dynamical transitions in hydrogenous materials using transmission measurements with very cold neutrons  

SciTech Connect

We have tested the transmission of very cold neutrons as a method to measure dynamical transitions in hydrogenous materials. Transmitted intensities vs. temperature at 30 A neutron wavelength were measured for four materials that undergo phase transformations associated with changes in dynamics: ammonium iodide, sodium borohydride, hexamethylbenzene, and dicesium dodecahydro-closo-dodecaborate. In some cases, neutron vibrational spectra above and below the transformation temperatures are compared to the transmission results. The measurements show changes in transmission at or near the transition for all these compounds, reflecting dynamical changes. The results demonstrate that the transmission method is sensitive to motional changes due to a wide range of structural transitions, from first-order to much more subtle order-disorder effects and for both small molecular species and larger molecules. The technique is valuable for rapid (ca. hours) scans of new materials to guide neutron inelastic scattering experiments or to complement the results of other techniques. - Graphical abstract: The transmission of very long wavelength neutrons is a highly sensitive probe of dynamical transitions in hydrogenous materials. Highlights: > Transmission of very long wavelength neutrons can probe dynamical transitions. > The technique is sensitive for both first-order and order-disorder transformations. > Changes in dynamical behavior of small and large molecular species can be detected. > This method can be a valuable guide for complex neutron scattering experiments.

Verdal, Nina, E-mail: nina.verdal@nist.gov [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Udovic, Terrence J.; Copley, John R.D. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Rush, John J. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899-6102 (United States); Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742-2115 (United States)

2011-10-15T23:59:59.000Z

53

Efficient Bayesian estimation of Markov model transition matrices with given stationary distribution  

E-Print Network (OSTI)

Direct simulation of biomolecular dynamics in thermal equilibrium is challenging due to the metastable nature of conformation dynamics and the computational cost of molecular dynamics. Biased or enhanced sampling methods may improve the convergence of expectation values of equilibrium probabilities and expectation values of stationary quantities significantly. Unfortunately the convergence of dynamic observables such as correlation functions or timescales of conformational transitions relies on direct equilibrium simulations. Markov state models are well suited to describe both, stationary properties and properties of slow dynamical processes of a molecular system, in terms of a transition matrix for a jump process on a suitable discretiza- tion of continuous conformation space. Here, we introduce statistical estimation methods that allow a priori knowledge of equilibrium probabilities to be incorporated into the estimation of dynamical observables. Both, maximum likelihood methods and an improved Monte Carlo sampling method for reversible transition ma- trices with fixed stationary distribution are given. The sampling approach is applied to a toy example as well as to simulations of the MR121-GSGS-W peptide, and is demonstrated to converge much more rapidly than a previous approach in [F. Noe, J. Chem. Phys. 128, 244103 (2008)

Benjamin Trendelkamp-Schroer; Frank Noe

2013-01-10T23:59:59.000Z

54

Transit-Time Distributions in a Global Ocean Model  

Science Conference Proceedings (OSTI)

Results from a simulation of the ocean “transit-time distribution” (“TTD”) for global and regional ocean surface boundary conditions are presented based on a 5000-yr integration using the Parallel Ocean Program ocean general circulation model. ...

Synte Peacock; Mathew Maltrud

2006-03-01T23:59:59.000Z

55

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

56

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

57

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

58

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

59

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

60

DOE Hydrogen Analysis Repository: Hydrogen Transition Model ...  

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

Report ArticleAbstract Title: VII.11 Development of HyTrans Model and Integrated Scenario Analysis Page number(s): 1307 Publisher: U.S. Department of Energy Author...

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

62

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/

63

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

64

2009 Transition Dynamics Enterprises, Inc. Used with permission. What You Need to  

E-Print Network (OSTI)

electricity to end users Consumption Mgmt ­ real time assessment of power usage #12;2009 Transition Dynamics industry sectors that: Provide superior performance at lower costs Greatly reducing or eliminating energy Transmission ­ move electricity from one region to another Distribution ­ distributing

Escher, Christine

65

Engineering models of deflagration-to-detonation transition  

Science Conference Proceedings (OSTI)

For the past two years, Los Alamos has supported research into the deflagration-to-detonation transition (DDT) in damaged energetic materials as part of the explosives safety program. This program supported both a theory/modeling group and an experimentation group. The goal of the theory/modeling group was to examine the various modeling structures (one-phase models, two-phase models, etc.) and select from these a structure suitable to model accidental initiation of detonation in damaged explosives. The experimental data on low-velocity piston supported DDT in granular explosive was to serve as a test bed to help in the selection process. Three theoretical models have been examined in the course of this study: (1) the Baer-Nunziato (BN) model, (2) the Stewart-Prasad-Asay (SPA) model and (3) the Bdzil-Kapila-Stewart model. Here we describe these models, discuss their properties, and compare their features.

Bdzil, J.B.; Son, S.F.

1995-07-01T23:59:59.000Z

66

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

67

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

68

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

69

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

70

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

71

Width bifurcation and dynamical phase transitions in open quantum systems  

E-Print Network (OSTI)

The states of an open quantum system are coupled via the environment of scattering wavefunctions. The complex coupling coefficients $\\omega$ between system and environment arise from the principal value integral and the residuum. At high level density where the resonance states overlap, the dynamics of the system is determined by exceptional points. At these points, the eigenvalues of two states are equal and the corresponding eigenfunctions are linearly dependent. It is shown in the present paper that Im$(\\omega)$ and Re$(\\omega)$ influence the system properties differently in the surrounding of exceptional points. Controlling the system by a parameter, the eigenvalues avoid crossing in energy near an exceptional point under the influence of Re$(\\omega)$ in a similar manner as it is well known from discrete states. Im$(\\omega)$ however leads to width bifurcation and finally (when the system is coupled to one channel, i.e. to a common continuum of scattering wavefunctions), to a splitting of the system into two parts with different characteristic time scales. Physically, the system is stabilized by this splitting since the lifetimes of most ($N-1$) states are longer than before while that of only one state is shorter. In the cross section the short-lived state appears as a background term in high-resolution experiments. The wavefunctions of the long-lived states are mixed in those of the original ones in a comparably large parameter range. Numerical results for the eigenvalues and eigenfunctions are shown for $N=2, ~4$ and 10 states coupled mostly to 1 channel.

Hichem Eleuch; Ingrid Rotter

2013-03-26T23:59:59.000Z

72

PHASE TRANSITIONS, CRITICAL PHENOMENA AND EXACTLY SOLVABLE LATTICE MODELS  

E-Print Network (OSTI)

in a pond change phase from a liquid state to solid ice. Lastly, if a horseshoe magnet is heated T100 C L G Figure 1. Schematic phase diagram of water showing the solid ice, liquid and gasPHASE TRANSITIONS, CRITICAL PHENOMENA AND EXACTLY SOLVABLE LATTICE MODELS Paul A. Pearce1

Pearce, Paul A.

73

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

74

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

75

Tunneling dynamics and phase transition of a Bose-Fermi mixture in a double well  

Science Conference Proceedings (OSTI)

The coherent nonlinear tunneling dynamics of a boson-fermion mixture in a double-well potential is studied in this paper. Four types of phase are found for the mixture. The first one is two species localizing in different potential wells. The second one is two species coexisting in the same well. The third one is two species equally populated in two wells. The fourth one is one species equally populated in two wells while the other species is in one well. The phase transitions among these four states have been investigated. The interspecies and intraspecies interactions as well as bosonic and fermionic numbers can dramatically affect these phase transitions.

Qi Pengtang; Duan Wenshan [Department of Physics, Northwest Normal University, Lanzhou, 730070 (China)

2011-09-15T23:59:59.000Z

76

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

77

Integrated Market Modeling of Hydrogen Transition Scenarios with HyTrans  

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

Integrated Market Modeling of Integrated Market Modeling of Hydrogen Transition Scenarios with HyTrans Paul N. Leiby, David L. Greene and David Bowman Oak Ridge National Laboratory A presentation to the Hydrogen Delivery Analysis Meeting FreedomCAR and Fuels Partnership Delivery, Storage and Hydrogen Pathways Tech Teams May 8-9, 2007 Columbia, MD 2 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Drawing from several other DOE models, HyTrans integrates supply and demand in a dynamic non-linear market model to 2050. * H2A - Hydrogen Production - Hydrogen Delivery * PSAT & ASCM - Fuel economy - 2010/2015 cost & performance goals * ORNL Vehicle Choice Model - Fuel availability - Make & model diversity - Price, fuel economy, etc. * Vehicle Manufacturing Cost Estimates (assisted by OEMs)

78

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

79

"Liquid-gas" transition in the supercritical region: Fundamental changes in the particle dynamics  

E-Print Network (OSTI)

Recently, we have proposed a new dynamic line on the phase diagram in the supercritical region. Crossing this line corresponds to the radical changes of the fluid properties. Here, we focus on the dynamics of model Lennard-Jones and Soft-Sphere fluids. We show that the change of the dynamics from the liquid-like to gas-like can be established on the basis of the velocity autocorrelation function and mean-square displacement. Using the rigorous criterion, we show that the crossover of particle dynamics and key liquid properties occurs at the same line. We further show that positive sound dispersion disappears in the vicinity of this line in both kinds of systems. The dynamic line bears no relationship to the existence of the critical point. We find that the region of existence of liquid-like dynamics narrows with the increase of the exponent of the repulsive part of inter-particle potential.

V. V. Brazhkin; Yu. D. Fomin; A. G. Lyapin; V. N. Ryzhov; E. N. Tsiok; Kostya Trachenko

2013-05-16T23:59:59.000Z

80

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

82

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

83

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

84

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

85

Multifractal regime transition in a modified minority game model  

E-Print Network (OSTI)

The search for more realistic modeling of financial time series reviews several stylized facts of real markets. In this work we focus on the multifractal properties found in price and index signals. Although the usual Minority Game (MG) models do not exhibit multifractality, we study here one of its variants that does. We show that the nonsynchronous MG models in the nonergodic phase is multifractal and in this sense, together with other stylized facts, constitute a better modeling tool. Using the Structure Function (SF) approach we detected the stationary and the scaling range of the time series generated by the MG model and, from the linear (nonlinear) behavior of the SF we identified the fractal (multifractal) regimes. Finally, using the Wavelet Transform Modulus Maxima (WTMM) technique we obtained its multifractal spectrum width for different dynamical regimes.

Crepaldi, Antonio F; Ferreira, Fernando F; Francisco, Gerson

2007-01-01T23:59:59.000Z

86

Sustainable energy for developing countries : modelling transitions to renewable and clean energy in rapidly developing countries.  

E-Print Network (OSTI)

??The main objective of this thesis is first to adapt energy models for the use in developing countries and second to model sustainable energy transitions… (more)

Urban, Frauke

2009-01-01T23:59:59.000Z

87

A molecular dynamics simulation of the melting points and glass transition temperatures of myo-and neo-inositol  

E-Print Network (OSTI)

A molecular dynamics simulation of the melting points and glass transition temperatures of myo molecular potentials for atomistic simulation studies COMPASS H. Sun, J. Phys. Chem. B 102, 7338 1998 force field and molecular dynamics techniques. Our results show that the calculated heats of sublimation

de Gispert, Adrià

88

Shell model transition densities for electron and pion scattering  

Science Conference Proceedings (OSTI)

The general features of an effective interaction suitable for the calculation of cross-shell matrix elements in the /sup 16/O region are discussed. Shell-model transition densities are applied to the 1 hw excitation of non-normal parity states in light-nuclei, with /sup 13/C used as a prime example. The longitudinal form factors from such a calculation require enhancement and transverse form factors (spin-excitations) need to be quenched. The shapes of form factors also exhibit systematic discrepancies which are correlated with the discrepancies in magnitude. The problem with shapes is particularly marked for C1 form factors. It is shown that the addition of small components to the transition density, corresponding to the excitation of a single particle through two or three major shells, works in the right direction as far as both magnitude and shape are concerned and that such additions are particularly effective in the case of C1 excitations. For the transverse form factors in /sup 13/C, the use of Woods-Saxon radial wave functions leads to reductions of up to 50% compared with harmonic oscillator wave functions. The excitation of states with dominant multiparticle-multihole components, and the role played by admixtures of such configurations in low-lying states, is considered. Some of the problems associated with the use of shell-model bases extended to include high-lying configurations in the giant resonance region are pointed out. 15 refs., 15 figs., 1 tab.

Millener, D.J.

1987-01-01T23:59:59.000Z

89

Digital herders and phase transition in a voting model  

E-Print Network (OSTI)

In this paper, we discuss a voting model with two candidates, $C_1$ and $C_2$. We set two types of voters--herders and independents. The voting of independent voters is based on their fundamental values; on the other hand, the voting of herders is based on the number of votes. Herders always select the majority of the previous $r$ votes, which is visible to them. We call them digital herders. We can accurately calculate the distribution of votes for special cases. When $r\\geq 3$, we find that a phase transition occurs at the upper limit of $t$, where $t$ is the discrete time (or number of votes). As the fraction of herders increases, the model features a phase transition beyond which a state where most voters make the correct choice coexists with one where most of them are wrong. On the other hand, when $rperformance is the same as that of the independent voters. At last, from the simple experiments, we recognize the behavior of human beings.

Hisakado, Masato

2011-01-01T23:59:59.000Z

90

Metal-Insulator Transitions in Degenerate Hubbard Models and  

E-Print Network (OSTI)

Mott-Hubbard metal-insulator transitions in N-fold degenerate Hubbard models are studied within the Gutzwiller approximation. For any rational filling with x (integer) electrons per site it is found that metal-insulator transition occurs at a critical correlation energy Uc(N,x) = Uc(N,2N ? x) = ?(N,x)|¯?(N,x)|, where ¯? is the band energy per particle for the uncorrelated Fermi-liquid state and ?(N,x) is a geometric factor which increases linearly with x. We propose that the alkali metal doped fullerides AxC60 can be described by a 3-fold degenerate Hubbard model. Using the current estimate of band width and correlation energy this implies that most of AxC60, at integer x, are Mott-Hubbard insulators and A3C60 is a strongly correlated metal. PACS numbers: 71.10.+x,71.30.+h,74.70.W 1 Typeset using REVTEXThe discovery of superconductivity in A3C60 [1] has spurred great interest in alkali metal doped fullerides [2]. Beside A3C60, stable phases such as Rb1C60, Na2C60, K4C60 were

Jian Ping Lu

2008-01-01T23:59:59.000Z

91

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

92

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

93

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

94

Parallel Graph Transformation for Model Simulation applied to Timed Transition Petri Nets  

Science Conference Proceedings (OSTI)

This work discusses the use of parallel graph transformation systems for (multi-formalism) modeling and simulation and their implementation in the meta-modeling tool AToM^3. As an example, a simulator for Timed Transition Petri Nets (TTPN) is modeled ... Keywords: model simulation, parallel graph transformation, timed transition Petri nets

J. de Lara; C. Ermel; G. Taentzer; K. Ehrig

2004-12-01T23:59:59.000Z

95

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

96

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

97

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

E-Print Network (OSTI)

Price elasticity of demand for crude oil: estimates for 2327] Krichene, N. World crude oil and natural gas: a demandIn contrast to synthetic crude oils produced from the above

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

98

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

E-Print Network (OSTI)

playing key role in peak-oil debate, future energy supply.of di?ering views of peak oil, including Yergin’s, isHubbert’s Peak: The Impending World Oil Shortage. Princeton

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

99

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

E-Print Network (OSTI)

CTL production Oil shale production Biofuels productionshale have zero Resource- Cost), while in GTL and CTL production,

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

100

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

E-Print Network (OSTI)

GTL production CTL production Oil shale production Biofuelsoil and shale have zero Resource- Cost), while in GTL and CTL production,

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

E-Print Network (OSTI)

1] Andrews, S. and Udall, R. Oil Prophets: Lookingat World Oil Studies Over Time. In Campbell, C.International Workshop on Oil Depletion 2003, Paris, France,

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

102

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

E-Print Network (OSTI)

testing their above-ground shale oil retorting technology.and Miller, G. A. Oil shales and carbon dioxide. Science, [D. J. and Cecchine, G. Oil shale development in the United

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

103

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

E-Print Network (OSTI)

for CO2 evolved from oil shale. Fuel Processing Technology,E. T. and Miller, G. A. Oil shales and carbon dioxide.D. J. and Cecchine, G. Oil shale development in the United

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

104

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

E-Print Network (OSTI)

D. J. and Cecchine, G. Oil shale development in the Unitedresources of some world oil-shale deposits. Technical Reportfor CO2 evolved from oil shale. Fuel Processing Technology,

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

105

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

E-Print Network (OSTI)

response to high oil prices and geopolitical threats tofor the e?ect of the oil price through the price elasticityprojections, corresponding oil price series are extracted

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

106

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

E-Print Network (OSTI)

manufactured in two steps: a syngas comprised mainly of COfeedstock, then the syngas is converted into liquid fuel

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

107

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

108

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

109

Diagnosing the Relative Impact of “Sneaks,” “Phantoms,” and Volatility in Sequences of Lagged Ensemble Probability Forecasts with a Simple Dynamic Decision Model  

Science Conference Proceedings (OSTI)

Monte Carlo simulation of sequences of lagged ensemble probability forecasts is undertaken using Markov transition law estimated from a reforecast ensemble. A simple three-state, three-action dynamic decision model is then applied to the Monte ...

Justin G. McLay

2011-02-01T23:59:59.000Z

110

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

111

Dynamic nuclear polarization with simultaneous excitation of electronic and nuclear transitions  

E-Print Network (OSTI)

Dynamic nuclear polarization transfers spin polarization from electrons to nuclei. We have achieved this by a new method, simultaneously exciting transitions of electronic and nuclear spins. The efficiency of this technique improves with increasing magnetic field. Experimental results are shown for N@C60 with continuous-wave microwaves, which can be expected to produce even higher polarization than the corresponding pulsed techniques for electron spins greater than 1/2. The degree of nuclear polarization in this case can be easily monitored through the intensities of the well resolved hyperfine components in the EPR spectrum. The nuclear spin-lattice relaxation time is orders of magnitude longer than that of the electrons.

G. W. Morley; K. Porfyrakis; A. Ardavan; J. van Tol

2008-05-28T23:59:59.000Z

112

Dynamical Scaling of the Quantum Hall Plateau Transition F. Hohls,1,* U. Zeitler,1  

E-Print Network (OSTI)

.43.Fj Phase transitions between different phases of matter are frequently met in nature, e.g., in ice- and second-order transitions. In a first-order transition, the two phases coexist; in a second. Different from these types of classical phase transitions are quantum phase transitions. Strictly speak- ing

Hohls, Frank

113

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

114

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

115

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

116

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

117

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

118

Caloric curve for nuclear liquid-gas phase transition in relativistic mean-field hadronic model  

E-Print Network (OSTI)

The main thermodynamical properties of the nuclear liquid-gas phase transition were explored in the framework of the relativistic mean-field hadronic model in three statistical ensembles: canonical, grand canonical and isobaric. We have found that the liquid-gas phase transition, i.e., the first order phase transition which is defined by the plateau in the isotherms, cannot contain the plateau in the caloric curves in the canonical and microcanonical ensembles. The plateau in the isotherms is incompatible with the plateau in the caloric curves at fixed baryon density. Moreover, for the nuclear liquid-gas phase transition the caloric curve has a plateau only at fixed pressure or chemical potential. The results of the statistical multifragmentation models for the nuclear liquid-gas phase transition were reanalyzed. It was revealed that one class of statistical multifragmentation models do indeed predict the nuclear liquid-gas phase transition for the nuclear multifragmentation. However, there is another class o...

Parvan, A S

2011-01-01T23:59:59.000Z

119

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.

120

Evaluation of Operational Model Cyclone Structure Forecasts during Extratropical Transition  

Science Conference Proceedings (OSTI)

Cyclone structure is known to be directly linked to the sensible weather effects produced by the weather system. The extratropical transition (ET) process leads to immense changes in cyclone structure and therefore to changes in the associated ...

Jenni L. Evans; Justin M. Arnott; Francesca Chiaromonte

2006-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

122

Hardening transition in a one-dimensional model for ferrogels  

E-Print Network (OSTI)

We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance.

M. A. Annunziata; A. M. Menzel; H. Löwen

2013-06-03T23:59:59.000Z

123

Gas Mileage of 2012 Vehicles by Azure Dynamics  

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

MODEL City Comb Hwy 2012 Azure Dynamics Transit Connect Electric Van Automatic (A1), Electricity Compare 2012 Azure Dynamics Transit Connect Electric Van kWh100 mi 55 City 54...

124

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

125

Glass Transition by Gelation in a Phase Separating Binary Alloy  

E-Print Network (OSTI)

We use molecular dynamics simulations to show that glass transition in a model phase separating amorphous alloy, Cu50Nb50, occurs by gelation. At the glass transition, a mechanically stiff, percolating network of atoms ...

Baumer, Richard E.

126

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

127

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

128

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...

129

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

130

Optimizing the Power Delivery Network in Dynamically Voltage Scaled Systems with Uncertain Power Mode Transition Times  

E-Print Network (OSTI)

, where state transition rates are controlled by actions a A. We consider a cost function which assigns matrix G is defined as an nÃ?n matrix, where an entry s,s' in G is called the transition rate from state s to another state s'. The transition rates may be calculated as follows, , ' '( ) ( ', ) (1/ ( , ')),s

Pedram, Massoud

131

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

132

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

133

Transition to model-driven engineering: what is revolutionary, what remains the same?  

Science Conference Proceedings (OSTI)

A considerable amount of research has been dedicated to bring the vision of model-driven engineering (MDE) to fruition. However, the practical experiences of organizations that transition to MDE are underreported. This paper presents a case study of ...

Jorge Aranda; Daniela Damian; Arber Borici

2012-09-01T23:59:59.000Z

134

Non-linear inversion modeling for Ultrasound Computer Tomography: transition from soft to hard tissues imaging  

E-Print Network (OSTI)

Non-linear inversion modeling for Ultrasound Computer Tomography: transition from soft to hard, the tomographic procedure used is adapted to broadband data acquired in scattering configurations while, Iterative Approximation, Soft Tissues Imaging, Hard Tissues Imaging, Breast, Bones 1. INTRODUCTION

135

Rail + Property Development: A model of sustainable transit finance and urbanism  

E-Print Network (OSTI)

sector investments i n rail transit. References Bernick, M .L. and Spit, T. 1998. Cities on Rail. London: Spon Press.Study of the Integrated Rail-Property Development Model in

Cervero, Robert; Murakami, Jin

2008-01-01T23:59:59.000Z

136

Numerical Simulations and a Conceptual Model of the Stratocumulus to Trade Cumulus Transition  

Science Conference Proceedings (OSTI)

A two-dimensional eddy-resolving model is used to study the transition from the stratocumulus topped boundary layer to the trade cumulus boundary layer. The 10-day simulations use an idealized Lagrangian trajectory representative of summertime ...

Matthew C. Wyant; Christopher S. Bretherton; Hugh A. Rand; David E. Stevens

1997-01-01T23:59:59.000Z

137

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

138

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

139

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

140

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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.


141

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

142

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

143

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

144

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

145

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

146

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

147

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

148

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

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

Liquid-gas phase transition in a two-components isospin lattice gas model for asymmetric nuclear matter  

E-Print Network (OSTI)

A two-components isospin lattice gas model has been employed to study the liquid-gas phase transition for asymmetric nuclear matter. An additional degree of freedom, namely, the asymmetry parameter alpha has been considered carefully for studying the phase transition. We have shown that under the mean field approximation, the liquid-gas phase transition given by this model is of second order. The entropy continues at the phase transition point. The binodal surface is addressed.

Wei Liang Qian; Ru-Keng Su

2002-10-04T23:59:59.000Z

157

High-precision molecular dynamics simulation of UO2-PuO2: superionic transition in uranium dioxide  

E-Print Network (OSTI)

Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the rigid ions approximation using high-performance graphics processors (GPU). In this article we assess the 10 most relevant interatomic sets of pair potential (SPP) by reproduction of the Bredig superionic phase transition (anion sublattice premelting) in uranium dioxide. The measurements carried out in a wide temperature range from 300K up to melting point with 1K accuracy allowed reliable detection of this phase transition with each SPP. The {\\lambda}-peaks obtained are smoother and wider than it was assumed previously. In addition, for the first time a pressure dependence of the {\\lambda}-peak characteristics was measured, in a range from -5 GPa to 5 GPa its amplitudes had parabolic plot and temperatures had linear (that is similar to the Clausius-Clapeyron equation for melting temperature).

Potashnikov, S I; Nekrasov, K A; Kupryazhkin, A Ya

2011-01-01T23:59:59.000Z

158

Phase transitions in the two-dimensional ferro- and antiferromagnetic potts models on a triangular lattice  

Science Conference Proceedings (OSTI)

The phase transitions in the two-dimensional ferro- and antiferromagnetic Potts models with q = 3 states of spin on a triangular lattice are studied using cluster algorithms and the classical Monte Carlo method. Systems with linear sizes L = 20-120 are considered. The method of fourth-order Binder cumulants and histogram analysis are used to discover that a second-order phase transition occurs in the ferromagnetic Potts model and a first-order phase transition takes place in the antiferromagnetic Potts model. The static critical indices of heat capacity ({alpha}), magnetic susceptibility ({gamma}), magnetization ({beta}), and correlation radius index ({nu}) are calculated for the ferromagnetic Potts model using the finite-size scaling theory.

Murtazaev, A. K.; Babaev, A. B., E-mail: b_albert78@mail.ru [Russian Academy of Sciences, Institute of Physics, Dagestan Scientific Center (Russian Federation)

2012-12-15T23:59:59.000Z

159

Winding Transitions at Finite Energy and Temperature: An O(3) Model  

E-Print Network (OSTI)

Winding number transitions in the two dimensional softly broken O(3) nonlinear sigma model are studied at finite energy and temperature. New periodic instanton solutions which dominate the semiclassical transition amplitudes are found analytically at low energies, and numerically for all energies up to the sphaleron scale. The Euclidean period beta of these finite energy instantons increases with energy, contrary to the behavior found in the abelian Higgs model or simple one dimensional systems. This results in a sharp crossover from instanton dominated tunneling to sphaleron dominated thermal activation at a certain critical temperature. Since this behavior is traceable to the soft breaking of conformal invariance by the mass term in the sigma model, semiclassical winding number transition amplitudes in the electroweak theory in 3+1 dimensions should exhibit a similar sharp crossover. We argue that this is indeed the case in the standard model for M_H < 4 M_W.

Salman Habib; Emil Mottola; Peter Tinyakov

1996-08-14T23:59:59.000Z

160

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Application of fracture toughness scaling models to the ductile-to- brittle transition  

SciTech Connect

An experimental investigation of fracture toughness in the ductile-brittle transition range was conducted. A large number of ASTM A533, Grade B steel, bend and tension specimens with varying crack lengths were tested throughout the transition region. Cleavage fracture toughness scaling models were utilized to correct the data for the loss of constraint in short crack specimens and tension geometries. The toughness scaling models were effective in reducing the scatter in the data, but tended to over-correct the results for the short crack bend specimens. A proposed ASTM Test Practice for Fracture Toughness in the Transition Range, which employs a master curve concept, was applied to the results. The proposed master curve over predicted the fracture toughness in the mid-transition and a modified master curve was developed that more accurately modeled the transition behavior of the material. Finally, the modified master curve and the fracture toughness scaling models were combined to predict the as-measured fracture toughness of the short crack bend and the tension specimens. It was shown that when the scaling models over correct the data for loss of constraint, they can also lead to non-conservative estimates of the increase in toughness for low constraint geometries.

Link, R.E. [Naval Surface Warfare Center, Annapolis, MD (United States); Joyce, J.A. [Naval Academy, Annapolis, MD (United States)

1996-01-01T23:59:59.000Z

162

Policy iteration based on a learned transition model  

Science Conference Proceedings (OSTI)

This paper investigates a reinforcement learning method that combines learning a model of the environment with least-squares policy iteration (LSPI). The LSPI algorithm learns a linear approximation of the optimal state-action value function; the idea ...

Vivek Ramavajjala; Charles Elkan

2012-09-01T23:59:59.000Z

163

Modeling Convective Transitions in the Presence of Sea lce  

Science Conference Proceedings (OSTI)

A substantial part of the variability in the thermohaline circulation on decadal and longer timescales as found in ocean models is strongly related to the deep-water formation (DWF) process. Many of these studies, however, neglected the role of ...

G. Lenderink; R. J. Haarsma

1996-08-01T23:59:59.000Z

164

Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models  

SciTech Connect

Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems architectures, even in cases for which high-precision Doppler follow-up is impractical.

Fabrycky, Daniel C.; /UC, Santa Cruz; Ford, Eric B.; /Florida U.; Steffen, Jason H.; /Fermilab; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Moorhead, Althea V.; /Florida U.; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Bryson, Steve; /NASA, Ames; Buchhave, Lars A.; /Bohr Inst. /Copenhagen U.; Christiansen, Jessie L.; /SETI Inst., Mtn. View /NASA, Ames /Caltech

2012-01-01T23:59:59.000Z

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

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

173

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

174

Isospin Lattice-Gas Model and Liquid-Gas Phase Transition in Asymmetric Nuclear Matter  

E-Print Network (OSTI)

An isospin lattice-gas model, which is a spin-1 Ising model, is employed to investigate the liquid-gas phase transition in asymmetric nuclear matter. We consider nuclear matter as a lattice where each lattice site can be either empty or occupied by a proton or a neutron, with a nearest-neighbor interaction among the nucleons. With the Bragg-Williams mean field approximation, we calculate various thermodynamic properties of nuclear matter for different densities and different proton-neutron asymmetry parameter s. Our model exhibits liquidgas phase transition below a critical temperature Tc, and predicts a monotonic decreasing of Tc as the magnitude of s is increased. The dependence of the nuclear matter isotherms on the asymmetry parameter s is discussed. Ray, Shamanna and Kuo / Liquid-gas phase transition in Nuclear matter 2 1.

S. Ray; J. Shamanna; T. T. S. Kuo

2008-01-01T23:59:59.000Z

175

Regime Transitions in a Stochastically Forced Double-Gyre Model  

Science Conference Proceedings (OSTI)

A reduced-gravity double-gyre ocean model is used to study the influence of an additive stochastic wind stress component on the regime behavior of the wind-driven circulation. The variance of the stochastic component (spatially coherent white ...

Philip Sura; Klaus Fraedrich; Frank Lunkeit

2001-02-01T23:59:59.000Z

176

Capacity planning in a transitional economy: What issues? Which models?  

SciTech Connect

This paper is devoted to an exploration of the important issues facing the Russian power generation system and its evolution in the foreseeable future and the kinds of modeling approaches that capture those issues. These issues include, for example, (1) trade-offs between investments in upgrading and refurbishment of existing thermal (fossil-fired) capacity and safety enhancements in existing nuclear capacity versus investment in new capacity, (2) trade-offs between investment in completing unfinished (under construction) projects based on their original design versus investment in new capacity with improved design, (3) incorporation of demand-side management options (investments in enhancing end-use efficiency, for example) within the planning framework, (4) consideration of the spatial dimensions of system planning including investments in upgrading electric transmission networks or fuel shipment networks and incorporating hydroelectric generation, (5) incorporation of environmental constraints and (6) assessment of uncertainty and evaluation of downside risk. Models for exploring these issues include low power shutdown (LPS) which are computationally very efficient, though approximate, and can be used to perform extensive sensitivity analyses to more complex models which can provide more detailed answers but are computationally cumbersome and can only deal with limited issues. The paper discusses which models can usefully treat a wide range of issues within the priorities facing decision makers in the Russian power sector and integrate the results with investment decisions in the wider economy.

Mubayi, V.; Leigh, R.W. [Brookhaven National Lab., Upton, NY (United States); Bright, R.N. [Anylec Research, Inc., Bayport, NY (United States)

1996-03-01T23:59:59.000Z

177

Scaling up transit priority modelling using high-throughput computing  

Science Conference Proceedings (OSTI)

The optimization of Road Space Allocation (RSA) from a network perspective is computationally challenging. An analogue to the Network Design Problem (NDP), RSA can be classified NP-hard. In large-scale networks when the number of alternatives increases ... Keywords: genetic algorithm, high-performance computing, high-throughput computing, transport modelling

Mahmoud Mesbah, Majid Sarvi, Jefferson Tan, Fateme Karimirad

2012-01-01T23:59:59.000Z

178

Solid-solid collapse transition in a two dimensional model molecular system  

E-Print Network (OSTI)

Solid-solid collapse transition in open framework structures is ubiquitous in nature. The real difficulty in understanding detailed microscopic aspects of such transitions in molecular systems arises from the interplay between different energy and length scales involved in molecular systems, often mediated through a solvent. In this work we employ Monte Carlo (MC) simulations to study the collapse transition in a model molecular system interacting via both isotropic as well as anisotropic interactions having different length and energy scales. The model we use is known as Mercedes-Benz (MB) which for a specific set of parameters sustains three solid phases: honeycomb, oblique and triangular. In order to study the temperature induced collapse transition, we start with a metastable honeycomb solid and induce transition by heating. High density oblique solid so formed has two characteristic length scales corresponding to isotropic and anisotropic parts of interaction potential. Contrary to the common believe and classical nucleation theory, interestingly, we find linear strip-like nucleating clusters having significantly different order and average coordination number than the bulk stable phase. In the early stage of growth, the cluster grows as linear strip followed by branched and ring-like strips. The geometry of growing cluster is a consequence of the delicate balance between two types of interactions which enables the dominance of stabilizing energy over the destabilizing surface energy. The nuclei of stable oblique phase are wetted by intermediate order particles which minimizes the surface free energy. We observe different pathways for pressure and temperature induced transitions.

Rakesh S. Singh; Biman Bagchi

2013-04-11T23:59:59.000Z

179

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

180

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Noise-Induced Transitions in a Simplified Model of the Thermohaline Circulation  

Science Conference Proceedings (OSTI)

A simplified box ocean model for the North Atlantic is used to study the influence of multiplicative short-term climate variability on the stability and long-term dynamics of the North Atlantic thermohaline circulation. A timescale separation ...

Axel Timmermann; Gerrit Lohmann

2000-08-01T23:59:59.000Z

182

Multiple Equilibria and Transitions in a Coupled Ocean–Atmosphere Box Model  

Science Conference Proceedings (OSTI)

A six-box model is employed as a prototype of the coupled Atlantic ocean–atmosphere system. Ice dynamics are excluded. Numerical integration of this system shows that different thermohaline circulation patterns are possible under the same forcing ...

Sergey V. Kravtsov; William K. Dewar

1998-02-01T23:59:59.000Z

183

The nuclear liquid-gas phase transition within Fermionic Molecular Dynamics  

E-Print Network (OSTI)

The time evolution of excited nuclei, which are in equilibrium with the surrounding vapour, is investigated. It is shown that the finite nuclear systems undergo a first oder phase transition. The caloric curve is presented for excited Oxygen, Magnesium, Aluminum and Calcium and the critical temperature is estimated for Oxygen.

J. Schnack; H. Feldmeier

1997-03-19T23:59:59.000Z

184

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

185

Effect of polymer-nanoparticle interactions on the glass transition dynamics and the conductivity mechanism in polyurethane titanium dioxide nanocomposites  

Science Conference Proceedings (OSTI)

We report on the glass transition dynamics and the conductivity properties of a nanodielectric system composed of pre-synthesized TiO{sub 2} nanoparticles embedded in thermoplastic polyurethane. Increase of TiO{sub 2} loading results in enhanced segmental mobility of the composites and less steep temperature dependence, i.e., lower fragility index. The decrease in the fragility index and glass transition temperature is discussed based on the FTIR results. We observe different behavior of conductivity for temperatures above and below the glass transition temperature. At high temperatures the composites exhibit conductivity values more than 2 orders of magnitude higher than those in the pristine matrix. At the same time, at sub-Tg temperatures composites are characterized by superior electrical insulation properties compared to pristine matrix material. Such drastic temperature dependence of the conductivity/insulating ability of the flexible and light-weight, low-Tg composite material can be utilized in various applications including sensing and temperature switching materials.

Polyzos, Georgios [ORNL; Tuncer, Enis [ORNL; Agapov, Alexander L [ORNL; Stevens, Derrick [ORNL; Sokolov, Alexei P [ORNL; Kidder, Michelle [ORNL; Jacobs, [Air Force Research Laboratory, Wright-Patterson AFB, OH; Koerner, Hilmar [Air Force Research Laboratory, Wright-Patterson AFB, OH; Vaia, Richard [Air Force Research Laboratory, Wright-Patterson AFB, OH; More, Karren Leslie [ORNL; Sauers, Isidor [ORNL

2012-01-01T23:59:59.000Z

186

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

187

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

188

The Hydrogen Infrastructure Transition (HIT) Model and Its Application in Optimizing a 50-year Hydrogen Infrastructure for Urban Beijing  

E-Print Network (OSTI)

a Hydrogen Energy Infrastructure." Annual Review of EnergyZoia (2005). "Hydrogen infrastructure strategic planning06—05 The Hydrogen Infrastructure Transition Model (HIT) &

Lin, Zhenhong; Ogden, Joan M; Fan, Yueyue; Sperling, Dan

2006-01-01T23:59:59.000Z

189

The Hydrogen Infrastructure Transition Model (HIT) & Its Application in Optimizing a 50-year Hydrogen Infrastructure for Urban Beijing  

E-Print Network (OSTI)

a Hydrogen Energy Infrastructure." Annual Review of EnergyZoia (2005). "Hydrogen infrastructure strategic planning06—05 The Hydrogen Infrastructure Transition Model (HIT) &

Lin, Zhenhong; Ogden, J; Fan, Yueyue; Sperling, Dan

2006-01-01T23:59:59.000Z

190

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

191

Phase transition in the spanning-hyperforest model on complete hypergraphs  

E-Print Network (OSTI)

By using our novel Grassmann formulation we study the phase transition of the spanning-hyperforest model of the k-uniform complete hypergraph for any k>= 2. The case k=2 reduces to the spanning-forest model on the complete graph. Different k are studied at once by using a microcanonical ensemble in which the number of hyperforests is fixed. The low-temperature phase is characterized by the appearance of a giant hyperforest. The phase transition occurs when the number of hyperforests is a fraction (k-1)/k of the total number of vertices. The behaviour at criticality is also studied by means of the coalescence of two saddle points. As the Grassmann formulation exhibits a global supersymmetry we show that the phase transition is second order and is associated to supersymmetry breaking and we explore the pure thermodynamical phase at low temperature by introducing an explicit breaking field.

Bedini, Andrea; Sportiello, Andrea

2009-01-01T23:59:59.000Z

192

Phase transition in the spanning-hyperforest model on complete hypergraphs  

E-Print Network (OSTI)

By using our novel Grassmann formulation we study the phase transition of the spanning-hyperforest model of the k-uniform complete hypergraph for any k>= 2. The case k=2 reduces to the spanning-forest model on the complete graph. Different k are studied at once by using a microcanonical ensemble in which the number of hyperforests is fixed. The low-temperature phase is characterized by the appearance of a giant hyperforest. The phase transition occurs when the number of hyperforests is a fraction (k-1)/k of the total number of vertices. The behaviour at criticality is also studied by means of the coalescence of two saddle points. As the Grassmann formulation exhibits a global supersymmetry we show that the phase transition is second order and is associated to supersymmetry breaking and we explore the pure thermodynamical phase at low temperature by introducing an explicit breaking field.

Andrea Bedini; Sergio Caracciolo; Andrea Sportiello

2009-06-24T23:59:59.000Z

193

The Putative Liquid-Liquid Transition is a Liquid-Solid Transition in Atomistic Models of Water, Part II  

E-Print Network (OSTI)

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [J. Chem. Phys. 135, 134503 (2011) and arXiv:1107.0337v2]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, SW silicon and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate u...

Limmer, David T

2013-01-01T23:59:59.000Z

194

PNJL model analysis of the Roberge-Weiss transition endpoint at imaginary chemical potential  

E-Print Network (OSTI)

Motivated by lattice QCD studies we investigate the RW transition endpoint at imaginary chemical potential in a two-flavor PNJL model. We focus on the quark-mass dependence of the endpoint using different forms of the Polyakov-loop potential.

Scheffler, David; Wambach, Jochen

2011-01-01T23:59:59.000Z

195

Multiple sea-ice states and abrupt MOC transitions in a general circulation ocean model  

E-Print Network (OSTI)

Multiple sea-ice states and abrupt MOC transitions in a general circulation ocean model Yosef: 25 September 2012 Ã? Springer-Verlag Berlin Heidelberg 2012 Abstract Sea ice has been suggested, based-called ``sea-ice switch'' mech- anism. An important requirement for this mechanism is that multiple sea-ice

Ashkenazy, Yossi "Yosef"

196

On a phase field model for solid-liquid phase transitions  

E-Print Network (OSTI)

distinct phases. This is the case for solid-liquid mix- tures (e.g. ice-water or alloys duringOn a phase field model for solid-liquid phase transitions S. Benzoni-Gavage , L. Chupin , D. Jamet , and J. Vovelle December 3, 2010 Contents 1 Introduction 2 2 Phase field equations 3 2.1 Derivation

197

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

198

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

199

The Putative Liquid-Liquid Transition is a Liquid-Solid Transition in Atomistic Models of Water, Part II  

E-Print Network (OSTI)

This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [J. Chem. Phys. 135, 134503 (2011) and arXiv:1107.0337v2]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, SW silicon and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative nonequilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

David T. Limmer; David Chandler

2013-03-13T23:59:59.000Z

200

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...

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

202

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

203

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

204

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

205

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

206

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

207

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

208

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

209

Biology and Phase Transition - CECM  

E-Print Network (OSTI)

Dec 24, 2003 ... next · up · previous. Next: Kaufman and percolation Up: Phase Transition Models in Previous: Phase Transition Models in ...

210

Monte Carlo calculation of the transition temperature of the anisotropic three-dimensional {ital XY} model  

SciTech Connect

The transition temperature of the spatially anisotropic three-dimensional classical {ital XY} model is calculated by means of Monte Carlo (MC) simulations. In the {ital XY} model the spins are not restricted to the {ital XY} plane, as in the plane rotator model. The results are compared with a self-consistent harmonic approximation calculation (SCHA). In two dimensions the inclusion of effect of vortices pushes down the transition temperature from {ital T}{sub KT}/{ital J}=1.08, given by the standard SCHA to {ital T}{sub KT}/{ital J}=0.70, in good agreement with the MC estimate {ital T}{sub KT}/{ital J}=0.725. {copyright} {ital 1996 The American Physical Society.}

Costa, B.V.; Pereira, A.R.; Pires, A.S. [Departamento de Fisica, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte, 30161970 Minas Gerais (Brazil)] [Departamento de Fisica, Universidade Federal de Minas Gerais, CP 702, Belo Horizonte, 30161970 Minas Gerais (Brazil)

1996-08-01T23:59:59.000Z

211

Isospin Lattice-Gas Model and Liquid-Gas Phase Transition in Asymmetric Nuclear Matter  

E-Print Network (OSTI)

An isospin lattice-gas model, which is a spin-1 Ising model, is employed to investigate the liquid-gas phase transition in asymmetric nuclear matter. We consider nuclear matter as a lattice where each lattice site can be either empty or occupied by a proton or a neutron, with a nearest-neighbor interaction among the nucleons. With the Bragg-Williams mean field approximation, we calculate various thermodynamic properties of nuclear matter for different densities and different proton-neutron asymmetry parameter $s$. Our model exhibits liquid-gas phase transition below a critical temperature $T_c$, and predicts a monotonic decreasing of $T_c$ as the magnitude of $s$ is increased. The dependence of the nuclear matter isotherms on the asymmetry parameter $s$ is discussed.

S. Ray; J. Shamanna; T. T. S. Kuo

1996-08-13T23:59:59.000Z

212

Modeling-Computer Simulations At Walker-Lane Transitional Zone Region  

Open Energy Info (EERE)

Modeling-Computer Simulations At Walker-Lane Modeling-Computer Simulations At Walker-Lane Transitional Zone Region (Laney, 2005) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown Notes Assembling Crustal Geophysical Data for Geothermal Exploration in the Great Basin, Louie and Coolbaugh. We have compiled velocity information from sources in the literature, results of previous seismic experiments and earthquake-monitoring projects, and data donated from mining, geothermal, and petroleum companies. We also collected (May 2002 and August 2004) two new crustal refraction profiles across western Nevada and the northern and central Sierra. These sections had not been well characterized previously.

213

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

214

$?^{*}N?$ 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

215

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

216

Deconfinement transition in protoneutron stars: Analysis within the Nambu-Jona-Lasinio model  

Science Conference Proceedings (OSTI)

We study the effect of color superconductivity and neutrino trapping on the deconfinement transition of hadronic matter into quark matter in a protoneutron star. To describe the strongly interacting matter a two-phase picture is adopted. For the hadronic phase we use different parametrizations of a nonlinear Walecka model which includes the whole baryon octet. For the quark-matter phase we use an SU(3){sub f} Nambu-Jona-Lasinio effective model which includes color superconductivity. We impose color and flavor conservation during the transition in such a way that just deconfined quark matter is transitorily out of equilibrium with respect to weak interactions. We find that deconfinement is more difficult for small neutrino content and it is easier for lower temperatures although these effects are not too large. In addition they will tend to cancel each other as the protoneutron star cools and deleptonizes, resulting a transition density that is roughly constant along the evolution of the protoneutron star. According to these results the deconfinement transition is favored after substantial cooling and contraction of the protoneutron star.

Lugones, G.; Carmo, T. A. S. do [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas, Rua Santa Adelia, 166, 09210-170, Santo Andre (Brazil); Grunfeld, A. G. [CONICET, Rivadavia 1917, (1033) Buenos Aires (Argentina); Departmento de Fisica, Comision Nacional de Energia Atomica, (1429) Buenos Aires (Argentina); Department of Physics, Sultan Qaboos University, P.O. Box: 36 Al-Khode 123 Muscat (Oman); Scoccola, N. N. [CONICET, Rivadavia 1917, (1033) Buenos Aires (Argentina); Departmento de Fisica, Comision Nacional de Energia Atomica, (1429) Buenos Aires (Argentina); Universidad Favaloro, Solis 453, (1078) Buenos Aires (Argentina)

2010-04-15T23:59:59.000Z

217

ON THE TRANSITIONAL DISK CLASS: LINKING OBSERVATIONS OF T TAURI STARS AND PHYSICAL DISK MODELS  

Science Conference Proceedings (OSTI)

Two decades ago 'transitional disks' (TDs) described spectral energy distributions (SEDs) of T Tauri stars with small near-IR excesses, but significant mid- and far-IR excesses. Many inferred this indicated dust-free holes in disks possibly cleared by planets. Recently, this term has been applied disparately to objects whose Spitzer SEDs diverge from the expectations for a typical full disk (FD). Here, we use irradiated accretion disk models to fit the SEDs of 15 such disks in NGC 2068 and IC 348. One group has a 'dip' in infrared emission while the others' continuum emission decreases steadily at all wavelengths. We find that the former have an inner disk hole or gap at intermediate radii in the disk and we call these objects 'transitional disks' and 'pre-transitional disks' (PTDs), respectively. For the latter group, we can fit these SEDs with FD models and find that millimeter data are necessary to break the degeneracy between dust settling and disk mass. We suggest that the term 'transitional' only be applied to objects that display evidence for a radical change in the disk's radial structure. Using this definition, we find that TDs and PTDs tend to have lower mass accretion rates than FDs and that TDs have lower accretion rates than PTDs. These reduced accretion rates onto the star could be linked to forming planets. Future observations of TDs and PTDs will allow us to better quantify the signatures of planet formation in young disks.

Espaillat, C.; Andrews, S.; Qi, C.; Wilner, D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-78, Cambridge, MA 02138 (United States); Ingleby, L.; Calvet, N. [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Hernandez, J. [Centro de Investigaciones de Astronomia (CIDA), Merida 5101-A (Venezuela, Bolivarian Republic of); Furlan, E. [National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States); D'Alessio, P. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, 58089 Morelia, Michoacan (Mexico); Muzerolle, J., E-mail: cespaillat@cfa.harvard.edu, E-mail: sandrews@cfa.harvard.edu, E-mail: cqi@cfa.harvard.edu, E-mail: dwilner@cfa.harvard.edu, E-mail: lingleby@umich.edu, E-mail: ncalvet@umich.edu, E-mail: jesush@cida.ve, E-mail: Elise.Furlan@jpl.nasa.gov, E-mail: p.dalessio@crya.unam.mx, E-mail: muzerol@stsci.edu [Space Telescope Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2012-03-10T23:59:59.000Z

218

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

219

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

220

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Ab-initio study of structure and dynamical properties of crystalline ice. Phase Transitions 78 179  

E-Print Network (OSTI)

We investigated the structural and dynamical properties of a tetrahedrally coordinated crystalline ice from first principles based on density functional theory within the generalized gradient approximation with the projected augmented wave method. First, we report the structural behaviour of ice at finite temperatures based on the analysis of radial distribution functions obtained by molecular dynamics simulations. The results show how the ordering of the hydrogen bonding breaks down in the tetrahedral network of ice with entropy increase in agreement with the neutron diffraction data. We also calculated the phonon spectra of ice in a 3 × 1 × 1 supercell by using the direct method. So far, due to the direct method used in this calculation, the phonon spectra is obtained without taking into account the effect of polarization arising from dipole-dipole interactions of water molecules which is expected to yield the splitting of longitudinal and transverse optic modes at the ?-point. The calculated longitudinal acoustic velocities from the initial slopes of the acoustic mode is in a reasonable agreement with the neutron scatering data. The analysis of the vibrational density of states shows the existence of a boson peak at low energy of translational region a characteristic common to amorphous systems.

W. A. Adeagbo; A. Zayak; P. Entel

2005-01-01T23:59:59.000Z

222

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

223

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

224

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

225

Modeling the Oil Transition: A Summary of the Proceedings of the DOE/EPA Workshop on the Economic and Environmental Implications of Global Energy Transitions  

SciTech Connect

The global energy system faces sweeping changes in the next few decades, with potentially critical implications for the global economy and the global environment. It is important that global institutions have the tools necessary to predict, analyze and plan for such massive change. This report summarizes the proceedings of an international workshop concerning methods of forecasting, analyzing, and planning for global energy transitions and their economic and environmental consequences. A specific case, it focused on the transition from conventional to unconventional oil and other energy sources likely to result from a peak in non-OPEC and/or global production of conventional oil. Leading energy models from around the world in government, academia and the private sector met, reviewed the state-of-the-art of global energy modeling and evaluated its ability to analyze and predict large-scale energy transitions.

Greene, David L [ORNL

2007-02-01T23:59:59.000Z

226

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

227

Quantum Phase Transitions and Heat Capacity in a two-atoms Bose-Hubbard Model  

E-Print Network (OSTI)

We show that a two-atoms Bose-Hubbard model exhibits three different phases in the behavior of thermal entanglement in its parameter space. These phases are demonstrated to be traceable back to the existence of quantum phase transitions in the same system. Significant similarities between the behaviors of thermal entanglement and heat capacity in the parameter space are brought to light thus allowing to interpret the occurrence and the meaning of all these three phases.

Leggio, B; Messina, A

2011-01-01T23:59:59.000Z

228

Nuclear liquid-gas phase transition within the lattice gas model  

E-Print Network (OSTI)

We study the nuclear liquid-gas phase transition on the basis of a two-component lattice gas model. A Metropolis type of sampling method is used to generate microscopic states in the canonical ensemble. The effective equation of state and fragment mass distributions are evaluated in a wide range of temperatures and densities. A definition of the phase coexistence region appropriate for mesoscopic systems is proposed. The caloric curve resulting from different types of freeze-out conditions are presented.

J. Borg; I. N. Mishustin; J. P. Bondorf

1998-09-25T23:59:59.000Z

229

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

230

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

231

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

232

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

233

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

234

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

235

Caloric curve for nuclear liquid-gas phase transition in relativistic mean-field hadronic model  

E-Print Network (OSTI)

The main thermodynamical properties of the first order phase transition of the relativistic mean-field (RMF) hadronic model were explored in the isobaric, the canonical and the grand canonical ensembles on the basis of the method of the thermodynamical potentials and their first derivatives. It was proved that the first order phase transition of the RMF model is the liquid-gas type one associated with the Gibbs free energy $G$. The thermodynamical potential $G$ is the piecewise smooth function and its first order partial derivatives with respect to variables of state are the piecewise continuous functions. We have found that the energy in the caloric curve is discontinuous in the isobaric and the grand canonical ensembles at fixed values of the pressure and the chemical potential, respectively, and it is continuous, i.e. it has no plateau, in the canonical and microcanonical ensembles at fixed values of baryon density, while the baryon density in the isotherms is discontinuous in the isobaric and the canonical ensembles at fixed values of the temperature. The general criterion for the nuclear liquid-gas phase transition in the canonical ensemble was identified.

A. S. Parvan

2011-11-26T23:59:59.000Z

236

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

237

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

238

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

239

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

240

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

242

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

243

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

244

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

245

A Detailed Power Model for Field Programmable Gate Arrays  

E-Print Network (OSTI)

1998]. Therefore, the Transition Density Model is employed in this power model. The Transition Density, and are an important component of the total overall power. However, the original Transition Density model does and discharging of load and parasitic capacitances. Therefore, dynamic power is closely related to the transition

Wilton, Steve

246

The statistical multifragmentation model for liquid-gas phase transition with a compressible nuclear liquid  

E-Print Network (OSTI)

We propose a new formulation of the statistical multifragmentation model based on the analysis of the virial expansion for a system of the nuclear fragments of all sizes. The developed model not only enables us to account for short-range repulsion, but also to calculate the surface free energy which is induced by the interaction between the fragments. We propose a new parameterization for the liquid phase pressure which allows us to introduce a compressible nuclear liquid into the statistical multifragmentation model. The resulting model is exactly solvable and has no irregular behavior of the isotherms in the mixed phase region that is typical for mean-field models. The general conditions for the 1-st and 2-nd (or higher) order phase transitions are formulated. It is shown that all endpoints of the present model phase diagram are the tricritical points, if the Fisher exponent $\\tau$ is in the range $\\{3}{2} \\le \\tau \\le 2$. The treatment of nuclear liquid compressibility allows us to reduce the tricritical endpoint density of the statistical multifragmentation model to one third of the normal nuclear density. A specific attention is paid to of the fragment size distributions in the region of a negative surface tension at supercritical temperatures.

V. V. Sagun; A. I. Ivanytskyi; K. A. Bugaev; I. N. Mishustin

2013-06-10T23:59:59.000Z

247

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

248

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

249

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

250

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

251

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

252

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

253

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

254

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

255

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

256

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

257

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

258

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

259

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

260

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Effect of finite chemical potential on QGP-Hadron phase transition in a statistical model of fireball formation  

E-Print Network (OSTI)

We study the effect of finite chemical potential for the QGP constituents in the Ramanathan et al. statistical model (Phys.Rev.C70, 027903,2004). While the earlier computations using this model with vanishing chemical potentials indicated a weakly first order phase transition for the system in the vicinity of 170 MeV (Pramana, 68, 757, 2007), the introduction of finite values for the chemical potentials of the constituents makes the transition a smooth roll over of the phases, while allowing fireball formation with radius of a few "fermi" to take place. This seems to be in conformity with the latest consensus on the nature of the QGP-Hadron phase transition. Keywords: Quark Gluon Plasma, Quark Hadron Phase Transition

R. Ramanathan; Agam k. Jha; K. k. Gupta; S. S. Singh

2008-02-18T23:59:59.000Z

262

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

263

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

264

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

265

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

266

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

267

Modeling the oil Transition: A Summary of the Proceedings of the DOE/EPA Workshop on the Economic and Environmental Implications of Global Energy Transitions, February 2007  

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

7-014 7-014 Modeling the Oil Transition: A Summary of the Proceedings of the DOE/EPA Workshop on the Economic and Environmental Implications of Global Energy Transitions February 2007 David L. Greene, Editor DOCUMENT AVAILABILITY Reports produced after January 1, 1996, are generally available free via the U.S. Department of Energy (DOE) Information Bridge: Web site: http://www.osti.gov/bridge Reports produced before January 1, 1996, may be purchased by members of the public from the following source: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-605-6000 (1-800-553-6847) TDD: 703-487-4639 Fax: 703-605-6900 E-mail: info@ntis.fedworld.gov Web site: http://www.ntis.gov/support/ordernowabout.htm

268

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

269

Higgs boson resonance parameters and the finite temperature phase transition in a chirally invariant Higgs-Yukawa model  

E-Print Network (OSTI)

We study a chirally invariant Higgs-Yukawa model regulated on a space-time lattice. We calculate Higgs boson resonance parameters and mass bounds for various values of the mass of the degenerate fermion doublet. Also, first results on the phase transition temperature are presented. In general, this model may be relevant for BSM scenarios with a heavy fourth generation of quarks.

John Bulava; Philip Gerhold; Karl Jansen; Jim Kallarackal; Attila Nagy

2011-11-11T23:59:59.000Z

270

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

271

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

272

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

273

A Model Checking Approach to Evaluating System Level Dynamic Power Management Policies for Embedded Systems  

E-Print Network (OSTI)

, and state transitions, with a cumulative power dissipation model. However, as stated in [3], assessing state, is a sleep state, which the system transitions to, if it does not want to dissipate any power power dissipation rate, and different latency and energy consumptionto go back to the busy state

Gupta, Rajesh

274

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

275

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

276

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

277

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

278

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

279

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

280

Well-posedness of an extended model for water-ice phase transitions  

E-Print Network (OSTI)

We propose an improved model explaining the occurrence of high stresses due to the difference in specific volumes during phase transitions between water and ice. The unknowns of the resulting evolution problem are the absolute temperature, the volume increment, and the liquid fraction. The main novelty here consists in including the dependence of the specific heat and of the speed of sound upon the phase. These additional nonlinearities bring new mathematical difficulties which require new estimation techniques based on Moser iteration. We establish the existence of a global solution to the corresponding initial-boundary value problem, as well as lower and upper bounds for the absolute temperature. Assuming constant heat conductivity, we also prove uniqueness and continuous data dependence of the solution.

Krejci, Pavel

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "modeling transition dynamics" 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

Pressure-Tuning the Quantum Phase Transition in a Model 2-D Magnet |  

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

Reappearing Superconductivity Surprises Scientists Reappearing Superconductivity Surprises Scientists Manipulating Genes with Hidden TALENs A New Discovery Answers an Old Question Peering into the Interfaces of Nanoscale Polymeric Materials Ironing Out the Details of the Earth's Core Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Pressure-Tuning the Quantum Phase Transition in a Model 2-D Magnet APRIL 11, 2012 Bookmark and Share Argonne and University of Chicago physicist Sara Haravifard with the instrument on XSD beamline 6-ID-B at the APS used for the high-resolution, high-pressure structural measurements of SCBO at cryogenic temperatures. The fundamental interactions that determine how spins arrange themselves in

282

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

283

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

284

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

285

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

286

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

287

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

288

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

289

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

290

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

291

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

292

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

293

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

294

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

295

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

296

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

297

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

298

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

299

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

300

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

302

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

303

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

304

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

305

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

306

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

307

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

308

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.

309

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

310

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

311

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

312

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

313

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...

314

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

315

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

316

Baldrige Program Transition  

Science Conference Proceedings (OSTI)

The Baldrige Performance Excellence Program is transitioning to a Sustainable, Enterprise Model. ... A Vision to Be Among the Best. ...

2013-08-06T23:59:59.000Z

317

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

318

Applying the Inverse Average Magnitude Squared Coherence Index for Determining Order-Chaos Transition in a System Governed by Hénon Mapping Dynamics  

E-Print Network (OSTI)

The quantitative determination of the order-chaos transition in a nonlinear dynamical system described by Hénon mapping defined as x[n + 1] = 1.0 ? A ? x[n] 2 + B ? y[n],y[n + 1] = B ? x[n], where B = 0.3, and A is an adjustable control parameter, was made. This was achieved by applying the Inverse Average Magnitude-Squared Coherence Index (IAMSCI). This method is based on the Welch average periodogram technique and it has the advantage respect to nonlinear dynamical methods that it may be applied to any stationary signal by using discrete Fourier transform (DFT) representation which allows to operate on a short discrete-time series. Its effectiveness was demonstrated by comparing the results obtained by applying IAMSCI

Rubén Orozco Morales

2008-01-01T23:59:59.000Z

319

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

320

Evaluation of monsoon seasonality and the tropospheric biennial oscillation transitions in the CMIP models  

E-Print Network (OSTI)

Evaluation of monsoon seasonality and the tropospheric biennial oscillation transitions in the CMIP 26 October 2012. [1] Characteristics of the Indian and Australian summer monsoon systems preferred monsoon transitions between the two regions and from one year to another, that form parts

Ummenhofer, Caroline C.

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


321

A full factory transient simulation model for the analysis of expected performance in a transition period  

Science Conference Proceedings (OSTI)

Intel's Fab-18 is based in Israel, and has transitioned from producing 0.18-micron logic devices to producing 90nM flash products. During this transition period, the factory has de-ramped in volume of logic while ramping-up flash. AutoSched AP software ...

Moti Klein; Adar Kalir

2006-12-01T23:59:59.000Z

322

A Novel Phase of Compressed Bilayers That Models the Prestalk Transition  

Science Conference Proceedings (OSTI)

The force model of protein-mediated membrane fusion hypothesizes that fusion is driven by mechanical forces exerted on the membranes, but many details are unknown. Here, we investigated by x-ray diffraction the consequence of applying compressive force on a stack of membranes against the hydration barrier. We found that as the osmotic pressure increased, the lamellar phase transformed first to a new phase of tetragonal lattice (T-phase) over a narrow range of relative humidity, and then to a phase of rhombohedral lattice. The unit cell structure changed from parallel bilayers to a bent configuration with a point contact between adjacent bilayers and then to the stalk hemifusion configuration. The T-phase is discussed as a possible transition state in the membrane merging pathway of fusion. We estimate the work required to form the T-phase and the subsequent hemifusion-stalk-resembling R-phase. The work for the formation of a stalk is compatible with the energy estimated to be released by several SNARE complexes.

Qian, Shuo [ORNL

2012-01-01T23:59:59.000Z

323

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

324

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

325

Predictive Capability for Strongly Correlated Systems: Mott Transition in MnO, Multielectron Magnetic Moments, and Dynamics Effects in Correlated Materials  

SciTech Connect

There are classes of materials that are important to DOE and to the science and technology community, generically referred to as strongly correlated electron systems (SCES), which have proven very difficult to understand and to simulate in a material-specific manner. These range from actinides, which are central to the DOE mission, to transition metal oxides, which include the most promising components of new spin electronics applications as well as the high temperature superconductors, to intermetallic compounds whose heavy fermion characteristics and quantum critical behavior has given rise to some of the most active areas in condensed matter theory. The objective of the CMSN cooperative research team was to focus on the application of these new methodologies to the specific issue of Mott transitions, multi-electron magnetic moments, and dynamical properties correlated materials. Working towards this goal, the W&M team extended its first-principles phaseless auxiliary-field quantum Monte Carlo (AFQMC) method to accurately calculate structural phase transitions and excited states.

Krakauer, Henry; Zhang, Shiwei

2013-02-21T23:59:59.000Z

326

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

327

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

328

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.

329

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

330

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

331

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

332

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

333

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

334

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

335

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

336

Improved modeling of the Rossiter-McLaughlin effect for transiting exoplanets  

E-Print Network (OSTI)

We present an improved formula for the anomalous radial velocity of the star during planetary transits due to the Rossiter-McLaughlin (RM) effect. The improvement comes from a more realistic description of the stellar ...

Hirano, Teruyuki

337

Critical dynamics and decoherence  

SciTech Connect

We study dynamics of decoherence in a generic model where the environment is driven and undergoes a quantum phase transition. We model the environment by the Ising chain in the transverse field, and assume that the decohering system is a central spin-1/2. We found that when the environment is quenched slowly through the critical point, the decoherence factor of the central spin undergoes rapid decay that encodes the critical exponents of the environment. We also found that decoherence in a non-equilibrated, kink-contaminated, environment can be stronger than in a vacuum one. We derived a remarkably simple analytical expression that describes post-transition decoherence and predicts periodicities involving all system parameters. This research connects the fields of decoherence, quantum phase transitions, and Kibble-Zurek non-equilibrium dynamics.

Damski, Bogdan [Los Alamos National Laboratory; Quan, Haitao T [Los Alamos National Laboratory; Zurek, Wojciech H [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

338

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

339

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

340

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 "modeling transition dynamics" 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

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

342

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

343

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

344

Control Strategies For Transit Priority  

E-Print Network (OSTI)

Light Rail Transit," Transportation Research Record, No.Rail Signal Control Strategies by Combining Transit and Traffic Simulation Models," Transportation Research

Skabardonis, Alexander

1998-01-01T23:59:59.000Z

345

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.

346

Phase diagrams in the lattice RPM model: from order-disorder to gas-liquid phase transition  

E-Print Network (OSTI)

The phase behavior of the lattice restricted primitive model (RPM) for ionic systems with additional short-range nearest neighbor (nn) repulsive interactions has been studied by grand canonical Monte Carlo simulations. We obtain a rich phase behavior as the nn strength is varied. In particular, the phase diagram is very similar to the continuum RPM model for high nn strength. Specifically, we have found both gas-liquid phase separation, with associated Ising critical point, and first-order liquid-solid transition. We discuss how the line of continuous order-disorder transitions present for the low nn strength changes into the continuum-space behavior as one increases the nn strength and compare our findings with recent theoretical results by Ciach and Stell [Phys. Rev. Lett. {\\bf 91}, 060601 (2003)].

Alexandre Diehl; Athanassios Z. Panagiotopoulos

2004-12-03T23:59:59.000Z

347

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

348

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

349

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

350

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

351

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

352

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

353

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

354

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

355

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

356

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

357

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...

358

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

359

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

360

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...

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

362

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

363

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

364

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

365

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

366

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

367

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

368

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

369

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

370

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

371

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

372

Studies of transition metal and overlayers dynamics and magnetism by HE and spin-polarized metastable HE beam spectroscopies  

DOE Green Energy (OSTI)

Experimental results for the investigation of quantum delocalization of hydrogen on the Pd(111) surface; the investigation of the structural and dynamical trends in the growth of Cu overlayers on Pd(111) surface; and the investigation of the magnetic structure of the NiO(111) surface using spin-polarized metastable He beam scattering are included in this paper. Planned research is also discussed.

El-Batanouny, M.

1992-01-16T23:59:59.000Z

373

Astrophysical Implications of the QCD Phase Transition  

Science Conference Proceedings (OSTI)

The possible role of a first order QCD phase transition at nonvanishing quark chemical potential and temperature for cold neutron stars and for supernovae is delineated. For cold neutron stars, we use the NJL model with a nonvanishing color superconducting pairing gap, which describes the phase transition to the 2SC and the CFL quark matter phases at high baryon densities. We demonstrate that these two phase transitions can both be present in the core of neutron stars and that they lead to the appearance of a third family of solution for compact stars. In particular, a core of CFL quark matter can be present in stable compact star configurations when slightly adjusting the vacuum pressure to the onset of the chiral phase transition from the hadronic model to the NJL model. We show that a strong first order phase transition can have a strong impact on the dynamics of core collapse supernovae. If the QCD phase transition sets in shortly after the first bounce, a second outgoing shock wave can be generated which leads to an explosion. The presence of the QCD phase transition can be read off from the neutrino and antineutrino signal of the supernova.

Schaffner-Bielich, J. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Sagert, I. [Goethe University, Frankfurt, Germany; Hempel, M. [Goethe University, Frankfurt, Germany; Pagliara, G. [Ruprecht-Karls-Universitaet, Heidelberg, Germany; Fischer, T. [University of Basel; Mezzacappa, Anthony [ORNL; Thielemann, Friedrich-Karl W. [Universitat Basel, Switzerland; Liebendoerfer, Matthias [Universitat Basel, Switzerland

2009-01-01T23:59:59.000Z

374

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

375

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

376

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

377

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

378

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

379

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

380

Dissipative particle dynamics study of solvent mediated transitions in pores decorated with tethered polymer brushes in the form of stripes  

E-Print Network (OSTI)

We study self-assembly of a binary mixture of components A and B confined in a slit-like pore with the walls modified by the stripes of tethered brushes made of beads of a sort A. The emphasis is on solvent mediated transitions between morphologies when the composition of the mixture varies. For certain limiting cases of the pore geometry we found that an effective reduction of the dimensionality may lead to a quasi one- and two-dimensional demixing. The change of the environment for the chains upon changing the composition of the mixture from polymer melt to a good solvent conditions provides explanation for the mechanism of development of several solvent mediated morphologies and, in some cases, for switching between them. We found solvent mediated lamellar, meander and in-lined cylinder phases. Quantitative analysis of morphology structure is performed considering brush overlap integrals and gyration tensor components.

Ja. M. Ilnytskyi; S. Sokolowski; T. Patsahan

2013-03-25T23:59:59.000Z

Note: This page contains sample records for the topic "modeling transition dynamics" 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.


381

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

382

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

383

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

384

Stripe Disordering Transition  

E-Print Network (OSTI)

Abstract. We have recently begun Monte Carlo simulations of the dynamics of stripe phases in the cuprates. A simple model of spinodal decomposition of the holes allows us to incorporate Coulomb repulsion and coherency strains. We find evidence for a possible stripe disordering transition, at a temperature below the pseudogap onset. Experimental searches for such a transition can provide constraints for models of stripe formation. The relationship between stripe phases and the pseudogap in underdoped cuprates is not well understood. In our model [1–3] the pseudogap is primary. It represents an instability of the hole Fermi liquid driven by Van Hove nesting [4]. However, there is a competition of instabilities, with an antiferromagnet (or flux phase [5–7]) at half filling and a charge-density wave (CDW) at the bare Van Hove singularity (VHS) near optimal doping. This competition leads to a classical phase separation of the holes – two minima in the free energy [8,1]. This is restricted to a nanoscopic scale by long-range Coulomb effects, leading to phases similar to the experimentally observed stripe phases [9].

R. S. Markiewicz; M. T. Vaughn

1999-01-01T23:59:59.000Z

385

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

386

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

387

Liquid-gas phase transition in hot asymmetric nuclear matter with density-dependent relativistic mean-field models  

E-Print Network (OSTI)

The liquid-gas phase transition in hot asymmetric nuclear matter is studied within density-dependent relativistic mean-field models where the density dependence is introduced according to the Brown-Rho scaling and constrained by available data at low densities and empirical properties of nuclear matter. The critical temperature of the liquid-gas phase transition is obtained to be 15.7 MeV in symmetric nuclear matter falling on the lower edge of the small experimental error bars. In hot asymmetric matter, the boundary of the phase-coexistence region is found to be sensitive to the density dependence of the symmetry energy. The critical pressure and the area of phase-coexistence region increases clearly with the softening of the symmetry energy. The critical temperature of hot asymmetric matter separating the gas phase from the LG coexistence phase is found to be higher for the softer symmetry energy.

Guang-Hua Zhang; Wei-Zhou Jiang

2012-03-17T23:59:59.000Z

388

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D-Skyrme-Hartree-Fock Method  

E-Print Network (OSTI)

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. A constraint is placed on the two independent components of the quadrupole moment in order to self-consistently explore the shape phase space of nuclear configurations. The scheme employed naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state can be calculated across phase transitions from lower densities (where one dimensional Hartree-Fock suffices) through to uniform nuclear matter without recourse to interpolation techniques between density regimes described by different physical models.

W. G. Newton

2009-03-08T23:59:59.000Z

389

Modeling Nuclear Pasta and the Transition to Uniform Nuclear Matter with the 3D-Skyrme-Hartree-Fock Method  

E-Print Network (OSTI)

The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock+BCS study of the properties of inhomogeneous nuclear matter at densities and temperatures leading to the transition to uniform nuclear matter are presented. A constraint is placed on the two independent components of the quadrupole moment in order to self-consistently explore the shape phase space of nuclear configurations. The scheme employed naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state can be calculated across phase transitions from lower densities (where one dimensional Hartree-Fock suffices) through to uniform nuclear matter without recourse to interpolation techniques between density regimes described by different physical models.

Newton, W G

2009-01-01T23:59:59.000Z

390

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

391

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

392

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

393

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

394

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 ...

395

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

396

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

397

Transition dynamics between the multiple steady states in natural ventilation systems : from theories to applications in optimal controls  

E-Print Network (OSTI)

In this study, we investigated the multiple steady state behavior, an important observation in numerical and experimental studies in natural ventilation systems. The-oretical models are developed and their applications in ...

Yuan, Jinchao

2007-01-01T23:59:59.000Z

398

Role of Interactions between Aerosol Radiative Effect, Dynamics, and Cloud Microphysics on Transitions of Monsoon Intraseasonal Oscillations  

Science Conference Proceedings (OSTI)

Extended-range prediction of monsoon intraseasonal oscillations (MISOs), crucial for agriculture and water management, is limited by their event-to-event variability. Here, the authors propose a hypothesis supported by a number of model ...

Anupam Hazra; B. N. Goswami; Jen-Ping Chen

2013-07-01T23:59:59.000Z

399

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

400

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

402

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

403

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

404

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

405

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

406

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

407

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

408

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

409

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

410

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

411

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

412

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

413

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

414

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

415

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

416

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

417

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

418

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

419

Water drives peptide conformational transitions  

E-Print Network (OSTI)

Transitions between metastable conformations of a dipeptide are investigated using classical molecular dynamics simulation with explicit water molecules. The distribution of the surrounding water at different moments before the transitions and the dynamical correlations of water with the peptide's configurational motions indicate that water is the main driving force of the conformational changes.

Nerukh, Dmitry

2011-01-01T23:59:59.000Z

420

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

Note: This page contains sample records for the topic "modeling transition dynamics" 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

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

422

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

423

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

424

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

425

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 ...

426

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

427

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

428

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

429

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

430

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

431

Structure and Phase Transitions of Monolayers of Intermediate-length n-alkanes on Graphite Studied by Neutron Diffraction and Molecular Dynamics Simulation  

Science Conference Proceedings (OSTI)

We present evidence from neutron diffraction measurements and molecular dynamics (MD) simulations of three different monolayer phases of the intermediate-length alkanes tetracosane (n-C(24)H(50) denoted as C24) and dotriacontane (n-C(32)H(66) denoted as C32) adsorbed on a graphite basal-plane surface. Our measurements indicate that the two monolayer films differ principally in the transition temperatures between phases. At the lowest temperatures, both C24 and C32 form a crystalline monolayer phase with a rectangular-centered (RC) structure. The two sublattices of the RC structure each consists of parallel rows of molecules in their all-trans conformation aligned with their long axis parallel to the surface and forming so-called lamellas of width approximately equal to the all-trans length of the molecule. The RC structure is uniaxially commensurate with the graphite surface in its [110] direction such that the distance between molecular rows in a lamella is 4.26 A=sqrt[3a(g)], where a(g)=2.46 A is the lattice constant of the graphite basal plane. Molecules in adjacent rows of a lamella alternate in orientation between the carbon skeletal plane being parallel and perpendicular to the graphite surface. Upon heating, the crystalline monolayers transform to a 'smectic' phase in which the inter-row spacing within a lamella expands by approximately 10% and the molecules are predominantly oriented with the carbon skeletal plane parallel to the graphite surface. In the smectic phase, the MD simulations show evidence of broadening of the lamella boundaries as a result of molecules diffusing parallel to their long axis. At still higher temperatures, they indicate that the introduction of gauche defects into the alkane chains drives a melting transition to a monolayer fluid phase as reported previously.

Taub, H. [University of Missouri, Columbia; Hansen, F.Y. [Technical University of Denmark; Diama, Amand [National University of the Ivory Coast; Matthies, Blake [Goodyear Tire and Rubber Company, The; Criswell, Leah [University of Missouri, Columbia; Mo, Haiding [Advanced Optowave Corporation; Bai, M [University of Missouri, Columbia; Herwig, Kenneth W [ORNL

2009-01-01T23:59:59.000Z

432

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

433

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

434

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

435

Gas-liquid transition in the model of particles interacting at high energy  

E-Print Network (OSTI)

An application of the ideas of the inertial confinement fusion process in the case of particles interacting at high energy is investigated. A possibility of the gas-liquid transition in the gas is considered using different approaches. In particular, a shock wave description of interactions between particles is studied and a self-similar solution of Euler's equation is discussed. Additionally, Boltzmann equation is solved for self-consistent field (Vlasov's equation) in linear approximation for the case of a gas under external pressure and the corresponding change of Knudsen number of the system is calculated.

S. Bondarenko; K. Komoshvili

2012-03-25T23:59:59.000Z

436

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

437

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

438

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

439

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

440

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

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


441

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

442

Weather Regimes and Preferred Transition Paths in a Three-Level Quasigeostrophic Model  

Science Conference Proceedings (OSTI)

Multiple flow regimes are reexamined in a global, three-level, quasigeostrophic (QG3) model with realistic topography in spherical geometry. This QG3 model, using a T21 triangular truncation in the horizontal, has a fairly realistic climatology ...

D. Kondrashov; K. Ide; M. Ghil

2004-03-01T23:59:59.000Z

443

Chaos and dynamical trends in barred galaxies: bridging the gap between N-body simulations and time-dependent analytical models  

E-Print Network (OSTI)

Self-consistent N-body simulations are an efficient tool to study galactic dynamics. However, it can be challenging to use them for the detailed study of individual trajectories (or ensembles of trajectories). Such orbital studies are important to shed light on global phase space properties, which are the underlying cause of observed structures. The potentials needed to describe self-consistent models are in this case time-dependent. For this reason, we aim to investigate the different dynamical properties (such as regular and chaotic motion) of a non-autonomous galactic system, whose time-dependent potential adequately mimics certain realistic trends arising from N-body barred galaxy simulations. We construct a fully time-dependent analytical model, which manages to capture and reproduce several features of an N-body simulation. We model the gravitational potentials of three components (disc, bar and dark matter halo), whose time-dependent parameters are derived from an N-body simulation. We start by studying the dynamical stability of its reduced time-independent 2-degrees of freedom model by charting the different islands of stability associated with certain orbital morphologies and detecting the chaotic and regular regions. We then turn our interest to the full 3-degrees of freedom time-dependent case, where we show a few representative trajectories which experience different typical dynamical behaviours, i.e., an interplay between regular and chaotic motion for different epochs. Finally, we focus on the study of the underlying global dynamical transitions of the time-dependent system in terms of estimating the relative total fraction of (un)stable motion of an ensemble of initial conditions taken from the simulation and evolved with the time-dependent potential. We find that, for such an ensemble, the fraction of regular motion increases with time.

T. Manos; Rubens E. G. Machado

2013-11-14T23:59:59.000Z

444

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

445

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

446

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

447

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

448

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

449

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

450

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

451

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

452

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

453

Molecular Dynamics Simulation of the alpha-Helix to beta-Sheet Transition in Coiled Protein Filaments: Evidence for a Critical Filament Length Scale  

E-Print Network (OSTI)

The alpha-helix to beta-sheet transition (?-? transition) is a universal deformation mechanism in alpha-helix rich protein materials such as wool, hair, hoof, and cellular proteins. Through a combination of molecular and ...

Buehler, Markus J.

454

The SU(3)/Z_3 QCD(adj) deconfinement transition via the gauge theory/"affine" XY-model duality  

E-Print Network (OSTI)

Earlier, two of us and M. Unsal [arXiv:1112.6389] showed that some 4d gauge theories, compactified on a small spatial circle of size L and considered at temperatures 1/beta near deconfinement, are dual to 2d "affine" XY-spin models. We use the duality to study deconfinement in SU(3)/Z_3 theories with n_f>1 massless adjoint Weyl fermions, QCD(adj) on R^2 x S^1_beta x S^1_L. The"affine" XY-model describes two "spins" - compact scalars taking values in the SU(3) root lattice, with nearest-neighbor interactions and subject to an "external field" preserving the topological Z_3^t and a discrete Z_3^chi subgroup of the chiral symmetry of the 4d gauge theory. The equivalent Coulomb gas representation of the theory exhibits electric-magnetic duality, which is also a high-/low-temperature duality. A renormalization group analysis suggests - but is not convincing, due to the onset of strong coupling - that the self-dual point is a fixed point, implying a continuous deconfinement transition. Here, we study the nature of the transition via Monte Carlo simulations. The Z_3^t x Z_3^chi order parameter, its susceptibility, the vortex density, the energy per spin, and the specific heat are measured over a range of volumes, temperatures, and "external field" strengths (in the gauge theory, these correspond to magnetic bion fugacities). The finite-size scaling of the susceptibility and specific heat we find is characteristic of a first-order transition. Furthermore, for sufficiently large but still smaller than unity bion fugacity (as can be achieved upon an increase of the S^1_L size), at the critical temperature we find two distinct peaks of the energy probability distribution, indicative of a first-order transition, as has been seen in earlier simulations of the full 4d QCD(adj) theory. We end with discussions of the global phase diagram in the beta-L plane for different numbers of flavors.

Mohamed M. Anber; Scott Collier; Erich Poppitz

2012-11-12T23:59:59.000Z

455

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

456

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

457

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

458

A Monte Carlo model for seeded atomic flows in the transition regime  

Science Conference Proceedings (OSTI)

A simple model for the numerical determination of separation effects in seeded atomic gas flows is presented. The model is based on the known possibility to provide a statistically convergent estimate of the exact solution for a linear transport equation ... Keywords: Compressible flows, Monte Carlo simulation, Multi-component flows, Numerical methods, Rarefied flows

S. Longo; P. Diomede

2009-06-01T23:59:59.000Z

459

Transition to Aperiodic Variability in a Wind-Driven Double-Gyre Circulation Model  

Science Conference Proceedings (OSTI)

Multiple equilibria as well as periodic and aperiodic solution regimes are obtained in a barotropic model of the midlatitude ocean’s double-gyre circulation. The model circulation is driven by a steady zonal wind profile that is symmetric with ...

Kyung-Il Chang; Michael Ghil; Kayo Ide; Chung-Chieng Aaron Lai

2001-05-01T23:59:59.000Z

460

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

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


461

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

462

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

463

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

464

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

465

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

466

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

467

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

468

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

469

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

470

IMPROVED MODELING OF THE ROSSITER-McLAUGHLIN EFFECT FOR TRANSITING EXOPLANETS  

Science Conference Proceedings (OSTI)

We present an improved formula for the anomalous radial velocity of the star during planetary transits due to the Rossiter-McLaughlin (RM) effect. The improvement comes from a more realistic description of the stellar absorption line profiles, taking into account stellar rotation, macroturbulence, thermal broadening, pressure broadening, and instrumental broadening. Although the formula is derived for the case in which radial velocities are measured by cross-correlation, we show through numerical simulations that the formula accurately describes the cases where the radial velocities are measured with the iodine absorption-cell technique. The formula relies on prior knowledge of the parameters describing macroturbulence, instrumental broadening, and other broadening mechanisms, but even 30% errors in those parameters do not significantly change the results in typical circumstances. We show that the new analytic formula agrees with previous ones that had been computed on a case-by-case basis via numerical simulations. Finally, as one application of the new formula, we reassess the impact of the differential rotation on the RM velocity anomaly. We show that differential rotation of a rapidly rotating star may have a significant impact on future RM observations.

Hirano, Teruyuki; Winn, Joshua N.; Albrecht, Simon [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Suto, Yasushi; Taruya, Atsushi [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Narita, Norio [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sato, Bun'ei, E-mail: hirano@utap.phys.s.u-tokyo.ac.jp [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2011-12-01T23:59:59.000Z

471

Evaluating Enhanced Hydrological Representations in Noah LSM over Transition Zones: Implications for Model Development  

Science Conference Proceedings (OSTI)

The authors introduce and compare the performance of the unified Noah land surface model (LSM) and its augments with physically based, more conceptually realistic hydrologic parameterizations. Forty-five days of 30-min data collected over nine ...

Enrique Rosero; Zong-Liang Yang; Lindsey E. Gulden; Guo-Yue Niu; David J. Gochis

2009-06-01T23:59:59.000Z

472

Classification of Precipitation Types during Transitional Winter Weather Using the RUC Model and Polarimetric Radar Retrievals  

Science Conference Proceedings (OSTI)

A new hydrometeor classification algorithm that combines thermodynamic output from the Rapid Update Cycle (RUC) model with polarimetric radar observations is introduced. The algorithm improves upon existing classification techniques that rely ...

Terry J. Schuur; Hyang-Suk Park; Alexander V. Ryzhkov; Heather D. Reeves

2012-04-01T23:59:59.000Z

473

Modeling streamers in transformer oil: The transitional fast 3rd mode streamer  

E-Print Network (OSTI)

This paper presents an electro-thermal hydrodynamic model that explains the development of different streamer modes in transformer oil. The focus is on the difference between the slow 2nd and fast 3rd mode streamers ...

Zahn, Markus

474

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

475

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

476

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

477

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

478

Incorporating livability benefits into the Federal Transit Administration New Starts project evaluation process through accessibility-based modeling  

E-Print Network (OSTI)

The Department of Transportation's announcement of the "Livability initiative" for major transit projects in January 2010 has prompted the Federal Transit Administration (FTA) to reassess the criteria used in the evaluation ...

Ducas, Caroline R. (Caroline Rose)

2011-01-01T23:59:59.000Z

479

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

480

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

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