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1

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

2

Dynamics of the Structural Glass Transition and the p-Spin—Interaction Spin-Glass Model  

Science Journals Connector (OSTI)

The mathematical structure of the dynamical theory for the soft-spin version of the p-spin-interaction (p>2) spin-glass model is related to that for the dynamical theories of the structural glass transition. The phase transitions predicted by both theories are discussed. The spin-glass transition predicted by the dynamical theory is related to a broken-replica-symmetry equilibrium calculation.

T. R. Kirkpatrick and D. Thirumalai

1987-05-18T23:59:59.000Z

3

Pseudo Dynamic Transitional Modeling of Building Heating Energy Demand Using Artificial1 Neural Network2  

E-Print Network (OSTI)

Transitional Modeling of Building Heating Energy Demand Using Artificial1 Neural Network2 Subodh Paudel a.Lecorre@mines-nantes.fr9 Abstract10 This paper presents the building heating demand prediction model with occupancy profile Institution15 building and compared its results with static and other pseudo dynamic neural network models

Paris-Sud XI, Université de

4

Quantum Quenches and Off-Equilibrium Dynamical Transition in the Infinite-Dimensional Bose-Hubbard Model  

SciTech Connect

We study the off-equilibrium dynamics of the infinite-dimensional Bose-Hubbard model after a quantum quench. The dynamics can be analyzed exactly by mapping it to an effective Newtonian evolution. For integer filling, we find a dynamical transition separating regimes of small and large quantum quenches starting from the superfluid state. This transition is very similar to the one found for the fermionic Hubbard model by mean field approximations.

Sciolla, Bruno; Biroli, Giulio [Institut de Physique Theorique, CEA/DSM/IPhT-CNRS/URA 2306 CEA-Saclay, F-91191 Gif-sur-Yvette (France)

2010-11-26T23:59:59.000Z

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

Oak Woodland Vegetation Dynamics: A State and Transition Approach1  

E-Print Network (OSTI)

into a format that is sensible and accessible to natural resource managers. State and transition models have93 Oak Woodland Vegetation Dynamics: A State and Transition Approach1 Melvin R. George2 and Maximo and transition format. Keywords: Oak-woodlands, state and transition models, succession, vegetation dynamics

Standiford, Richard B.

7

Power law relaxation and glassy dynamics in Lebwohl-Lasher model near isotropic-nematic phase transition  

E-Print Network (OSTI)

Orientational dynamics in a liquid crystalline system near the isotropic-nematic (I-N) phase transition is studied using Molecular Dynamics simulations of the well-known Lebwohl-Lasher (LL) model. As the I-N transition temperature is approached from the isotropic side, we find that the decay of the orientational time correlation functions (OTCF) slows down noticeably, giving rise to a power law decay at intermediate timescales. The angular velocity time correlation function also exhibits a rather pronounced power law decay near the I-N boundary. In the mean squared angular displacement at comparable timescales, we observe the emergence of a \\emph{subdiffusive regime} which is followed by a \\emph{superdiffusive regime} before the onset of the long-time diffusive behavior. We observe signature of dynamical heterogeneity through \\emph{pronounced non-Gaussian behavior in orientational motion} particularly at lower temperatures. This behavior closely resembles what is usually observed in supercooled liquids. We obtain the free energy as a function of orientational order parameter by the use of transition matrix Monte Carlo method. The free energy surface is flat for the system considered here and the barrier between isotropic and nematic phases is vanishingly small for this weakly first-order phase transition, hence allowing large scale, collective and correlated orientational density fluctuations. This might be responsible for the observed power law decay of the OTCFs.

Suman Chakrabarty; Dwaipayan Chakrabarti; Biman Bagchi

2006-03-14T23:59:59.000Z

8

Dynamical First-Order Phase Transition in Kinetically Constrained Models of Glasses J. P. Garrahan,1  

E-Print Network (OSTI)

.40.ÿa An increasingly accepted view is that the phenomenol- ogy associated with the glass transition [1

van Wijland, Frédéric - Laboratoire Matière et Systèmes Complexes, Université Paris 7

9

Simulation of transition dynamics to high confinement in fusion plasmas  

E-Print Network (OSTI)

The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors.

Nielsen, A H; Madsen, J; Naulin, V; Rasmussen, J Juul; Wan, B N

2014-01-01T23:59:59.000Z

10

A phenomenological model of dynamical arrest of electron transfer in solvents in the glass-transition region  

E-Print Network (OSTI)

A phenomenological model of dynamical arrest of electron transfer in solvents in the glass 2004; published online 17 February 2005 A phenomenological model of electron transfer reactions-acceptor energy gaps dashed line in Fig. 1 differs from the equilibrium distribution. The present phenomenological

Matyushov, Dmitry

11

Kinetic Ising Model of the Glass Transition  

Science Journals Connector (OSTI)

A graph theory of single-spin-flip kinetic Ising models is developed and applied to a class of spin models with strongly cooperative dynamics. Self-consistent approximations for the spin time correlation function are presented. One of the dynamical models exhibits a glass transition with no underlying thermodynamic singularity. The approximation for the time correlation function predicts a critical temperature, below which small fluctuations from equilibrium in the thermodynamic limit cannot relax in a finite amount of time.

Glenn H. Fredrickson and Hans C. Andersen

1984-09-24T23:59:59.000Z

12

Dynamic Transitions of Surface Tension Driven Convection  

E-Print Network (OSTI)

We study the well-posedness and dynamic transitions of the surface tension driven convection in a three-dimensional (3D) rectangular box with non-deformable upper surface and with free-slip boundary conditions. It is shown that as the Marangoni number crosses the critical threshold, the system always undergoes a dynamic transition. In particular, two different scenarios are studied. In the first scenario, a single mode losing its stability at the critical parameter gives rise to either a Type-I (continuous) or a Type-II (jump) transition. The type of transitions is dictated by the sign of a computable non-dimensional parameter, and the numerical computation of this parameter suggests that a Type-I transition is favorable. The second scenario deals with the case where the geometry of the domain allows two critical modes which possibly characterize a hexagonal pattern. In this case we show that the transition can only be either a Type-II or a Type-III (mixed) transition depending on another computable non-dimensional parameter. We only encountered Type-III transition in our numerical calculations. The second part of the paper deals with the well-posedness and existence of global attractors for the problem.

Henk Dijkstra; Taylan Sengul; Shouhong Wang

2011-05-05T23:59:59.000Z

13

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

14

Dynamics of stimulated L ? H transitions  

SciTech Connect

We report on model studies of stimulated L ? H transitions [K. Miki et al., Phys. Rev. Lett. 110, 195002 (2013)]. These studies use a reduced mesoscale model. Model studies reveal that L ? H transition can be triggered by particle injection into a subcritical state (i.e., Ptransition. For low ambient heating, strong injection is predicted to trigger a transient turbulence collapse. Repetitive injection at a period less than the lifetime of the collapsed state can thus maintain the turbulence collapse and so sustain a driven H-mode-like state. The total number of particles required to induce a transition by either injection or gas puffing is estimated. Results indicate that the total number of injected particles required is much smaller than that required for a transition by gas puffing. We thus show that internal injection is more efficient than gas puffing of comparable strength. We also observe that zonal flows do not play a critical role in stimulated transitions. For spontaneous transitions, the spike of the Reynolds work of turbulence on the zonal flow precedes the spike in the mean electric field shear. In contrast, we show that the two are coincident for stimulated transitions, suggesting that there is no causal link between zonal and mean flows for stimulated transitions.

Miki, K. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of) [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Center for Computational Science and e-Systems, Japan Atomic Energy Agency, Chiba 277-8587 (Japan); Diamond, P. H.; Xiao, W. W. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of) [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093 (United States); Hahn, S.-H. [KSTAR Team, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)] [KSTAR Team, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Gürcan, Ö. D. [LPP, Ecole Polytechnique, CNRS, 92118 Palaiseau Cedex (France)] [LPP, Ecole Polytechnique, CNRS, 92118 Palaiseau Cedex (France); Tynan, G. R. [Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093 (United States)] [Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093 (United States)

2013-08-15T23:59:59.000Z

15

Ising model: secondary phase transition  

E-Print Network (OSTI)

Lttice-spin phonons are considered, which make the heat capacity at the critical temperature satisfy experimental observations better. There is a BEC phase transition in an Ising model attributable to the lattice-spin phonons. We proved that the spin-wave theory only is available after BEC transition, and the magnons have the same characteristics as the lattice-spin phonons', resulting from quantum effect. Energy-level overlap effect at ultralow temperature is found. A prediction of BEC phase transition in a crystal is put forward as our theory generalization.

You-gang Feng

2012-04-09T23:59:59.000Z

16

Dynamics of Nucleation in the Ising Model  

Science Journals Connector (OSTI)

Dynamics of Nucleation in the Ising Model† ... Reactive pathways to nucleation in a three-dimensional Ising model at 60% of the critical temperature are studied using transition path sampling of single spin flip Monte Carlo dynamics. ... The application focuses on the simplest example of nucleation, that of a supercooled Ising model. ...

Albert C. Pan; David Chandler

2004-09-28T23:59:59.000Z

17

Crossover transition in bag-like models  

SciTech Connect

We formulate a simple model for a gas of extended hadrons at zero chemical potential by taking inspiration from the compressible bag model. We show that a crossover transition qualitatively similar to lattice QCD can be reproduced by such a system by including some appropriate additional dynamics. Under certain conditions, at high temperature, the system consist of a finite number of infinitely extended bags,which occupy the entire space. In this situation the system behaves as an ideal gas of quarks and gluons.

Ferroni, Lorenzo; Koch, Volker

2009-03-13T23:59:59.000Z

18

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.

19

MODEL UPDATING: TRANSITION FROM RESEARCH TO PRACTICE?  

SciTech Connect

This session offers an open forum to discuss issues associated with the transition of nearly two decades of engineering research into computational guided model updating into industry state-of-the-practice. Related technical issues are the model updating technology, model reduction, test-analysis correlation and optimization strategies. The session is organized as follows. Technical presentations review the state-of-the-art in finite element model updating and present examples of industrial applications. The results of a recent survey on the potential and usefulness of the model updating technology are discussed. Panel discussions and interaction with the audience discuss industrial needs, future trends and challenges and why negative model updating results are never discussed within the structural dynamics community.

D. C. ZIMMERMAN; F. M. HEMEZ

2000-10-01T23:59:59.000Z

20

Water-Peptide Dynamics during Conformational Transitions Dmitry Nerukh*,  

E-Print Network (OSTI)

Water-Peptide Dynamics during Conformational Transitions Dmitry Nerukh*, and Sergey Karabasov 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

Nerukh, Dmitry

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

Modeling Molecular Dynamics from Simulations  

SciTech Connect

Many important processes in biology occur at the molecular scale. A detailed understanding of these processes can lead to significant advances in the medical and life sciences. For example, many diseases are caused by protein aggregation or misfolding. One approach to studying these systems is to use physically-based computational simulations to model the interactions and movement of the molecules. While molecular simulations are computationally expensive, it is now possible to simulate many independent molecular dynamics trajectories in a parallel fashion by using super- or distributed- computing methods such as Folding@Home or Blue Gene. The analysis of these large, high-dimensional data sets presents new computational challenges. In this seminar, I will discuss a novel approach to analyzing large ensembles of molecular dynamics trajectories to generate a compact model of the dynamics. This model groups conformations into discrete states and describes the dynamics as Markovian, or history-independent, transitions between the states. I will discuss why the Markovian state model (MSM) is suitable for macromolecular dynamics, and how it can be used to answer many interesting and relevant questions about the molecular system. I will also discuss many of the computational and statistical challenges in building such a model, such as how to appropriately cluster conformations, determine the statistical reliability, and efficiently design new simulations.

Hinrichs, Nina Singhal (University of Chicago) [University of Chicago

2009-01-28T23:59:59.000Z

22

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

23

State and Transition Modeling History & Current Concepts  

E-Print Network (OSTI)

management input · Friedel(1991) concentrated on thresholds ­ "...compatible with state and transition theoryState and Transition Modeling History & Current Concepts Tamzen K. Stringham Oregon State vegetation change #12;· Non-equilibrium Models (States, Transitions and Thresholds) ­ Encompass Range

24

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

25

Bifurcation analysis and dimension reduction of a predator-prey model for the L-H transition  

SciTech Connect

The L-H transition denotes a shift to an improved confinement state of a toroidal plasma in a fusion reactor. A model of the L-H transition is required to simulate the time dependence of tokamak discharges that include the L-H transition. A 3-ODE predator-prey type model of the L-H transition is investigated with bifurcation theory of dynamical systems. The analysis shows that the model contains three types of transitions: an oscillating transition, a sharp transition with hysteresis, and a smooth transition. The model is recognized as a slow-fast system. A reduced 2-ODE model consisting of the full model restricted to the flow on the critical manifold is found to contain all the same dynamics as the full model. This means that all the dynamics in the system is essentially 2-dimensional, and a minimal model of the L-H transition could be a 2-ODE model.

Dam, Magnus; Brøns, Morten [Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)] [Department of Applied Mathematics and Computer Science, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Juul Rasmussen, Jens; Naulin, Volker [Association Euratom-DTU, Department of Physics, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde (Denmark)] [Association Euratom-DTU, Department of Physics, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde (Denmark); Xu, Guosheng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2013-10-15T23:59:59.000Z

26

Calorimetric glass transition explained by hierarchical dynamic facilitation  

E-Print Network (OSTI)

Calorimetric glass transition explained by hierarchical dynamic facilitation Aaron S. Keysa Contributed by David Chandler, February 11, 2013 (sent for review November 15, 2012) The glass transition different on cooling than on heating, and the response to melting a glass depends markedly on the cooling

Garrahan, Juan P.

27

Simple model for the Darwinian transition in early evolution  

E-Print Network (OSTI)

It has been hypothesized that in the era just before the last universal common ancestor emerged, life on earth was fundamentally collective. Ancient life forms shared their genetic material freely through massive horizontal gene transfer (HGT). At a certain point, however, life made a transition to the modern era of individuality and vertical descent. Here we present a minimal model for this hypothesized "Darwinian transition." The model suggests that HGT-dominated dynamics may have been intermittently interrupted by selection-driven processes during which genotypes became fitter and decreased their inclination toward HGT. Stochastic switching in the population dynamics with three-point (hypernetwork) interactions may have destabilized the HGT-dominated collective state and led to the emergence of vertical descent and the first well-defined species in early evolution. A nonlinear analysis of a stochastic model dynamics covering key features of evolutionary processes (such as selection, mutation, drift and HGT...

Arnoldt, Hinrich; Timme, Marc

2015-01-01T23:59:59.000Z

28

Models of Dynamical Supersymmetry Breaking  

E-Print Network (OSTI)

We review a class of models of dynamical supersymmetry breaking, and give a unified description of these models.

Lisa Randall

1997-06-23T23:59:59.000Z

29

QUANTUM DYNAMICS OF TRANSITION PROCESSES IN THE INTERACTING SYSTEMS  

E-Print Network (OSTI)

for the description of the simultaneous quantum dynamics of the open and closed string fields in the unified string transition processes as well as stationary regimes in pairs of the interacting systems with auto--oscillations of the simultaneous quan­ tum dynamics of closed and open string fields in the unified string field theory

30

Dynamic Modelling, Measurement and  

E-Print Network (OSTI)

Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders Justin Rae Elsey, B;Summary Co-rotating twin-screw extruders are unique and versatile machines that are used widely that these extruders are currently being optimally utilised. The most signi cant improvement to the eld of twin-screw

Fernandez, Thomas

31

Dynamics of Sleep Stage Transitions in Health and Disease  

Science Journals Connector (OSTI)

Sleep dynamics emerges from complex interactions between neuronal populations in many brain regions. Annotated sleep stages from electroencephalography (EEG) recordings could potentially provide a non?invasive way to obtain valuable insights into the mechanisms of these interactions and ultimately into the very nature of sleep regulation. However to date sleep stage analysis has been restricted only very recently expanding the scope of the traditional descriptive statistics to more dynamical concepts of the duration of and transitions between vigilance states and temporal evaluation of transition probabilities among different stages. Physiological and/or pathological implications of the dynamics of sleep stage transitions have to date not been investigated. Here we study detailed duration and transition statistics among sleep stages in healthy humans and patients with chronic fatigue syndrome known to be associated with disturbed sleep. We find that the durations of waking and non?REM sleep in particular deep sleep (Stages III and IV) during the nighttime follow a power?law probability distribution function while REM sleep durations follow an exponential function suggestive of complex underlying mechanisms governing the onset of light sleep. We also find a substantial number of REM to non?REM transitions in humans while this transition is reported to be virtually non?existent in rats. Interestingly the probability of this REM to non?REM transition is significantly lower in the patients than in controls resulting in a significantly greater REM to awake together with Stage I to awake transition probability. This might potentially account for the reported poor sleep quality in the patients because the normal continuation of sleep after either the lightest or REM sleep is disrupted. We conclude that the dynamical transition analysis of sleep stages is useful for elucidating yet?to?be?determined human sleep regulation mechanisms with a pathophysiological implication.

Akifumi Kishi; Zbigniew R. Struzik; Benjamin H. Natelson; Fumiharu Togo; Yoshiharu Yamamoto

2007-01-01T23:59:59.000Z

32

Phase Transition in a Model Gravitating System  

Science Journals Connector (OSTI)

We present recent developments in the study of an interacting gravitational system of concentric, spherical, mass shells. The existence of two distinct phases is demonstrated. The nature of the transition in the microcanonical, canonical, and grand canonical ensembles is studied both theoretically in terms of mean field theory and via dynamical simulation. Striking differences are found in each environment, especially the last.

Bruce N. Miller and Paige Youngkins

1998-11-30T23:59:59.000Z

33

Quantum phase transitions in the interacting boson model  

E-Print Network (OSTI)

This review is focused on various properties of quantum phase transitions (QPTs) in the Interacting Boson Model (IBM) of nuclear structure. The model in its infinite-size limit exhibits shape-phase transitions between spherical, deformed prolate, and deformed oblate forms of the ground state. Finite-size precursors of such behavior are verified by robust variations of nuclear properties (nuclear masses, excitation energies, transition probabilities for low lying levels) across the chart of nuclides. Simultaneously, the model serves as a theoretical laboratory for studying diverse general features of QPTs in interacting many-body systems, which differ in many respects from lattice models of solid-state physics. We outline the most important fields of the present interest: (a) The coexistence of first- and second-order phase transitions supports studies related to the microscopic origin of the QPT phenomena. (b) The competing quantum phases are characterized by specific dynamical symmetries and novel symmetry related approaches are developed to describe also the transitional dynamical domains. (c) In some parameter regions, the QPT-like behavior can be ascribed also to individual excited states, which is linked to the thermodynamic and classical descriptions of the system. (d) The model and its phase structure can be extended in many directions: by separating proton and neutron excitations, considering odd-fermion degrees of freedom or different particle-hole configurations, by including other types of bosons, higher order interactions, and by imposing external rotation. All these aspects of IBM phase transitions are relevant in the interpretation of experimental data and important for a fundamental understanding of the QPT phenomenon.

Pavel Cejnar; Jan Jolie

2008-07-22T23:59:59.000Z

34

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

35

Dynamical thickening transition in plate coating with concentrated surfactant solutions  

E-Print Network (OSTI)

We present a large range of experimental data concerning the influence of surfactants on the well-known Landau-Levich-Derjaguin experiment where a liquid film is generated by pulling a solid plate out of a bath. The thickness h of the film was measured as a function of the pulling velocity V for different kind of surfactant and at various concentrations. Measuring the thickening factor $\\alpha=h/h_{LLD}$, where hLLD is obtained for a pure liquid, in a wide range of capillary ($Ca=\\eta V/\\gamma$), two regimes of constant thickening can be identified: at small capillary number, $\\alpha$ is large due to a confinement and surface elasticity (or Marangoni) effects and at large Ca, $\\alpha$ is slightly higher than unity, due to surface viscous effects. At intermediate Ca, $\\alpha$ decreases as Ca increases along a "dynamic transition". In the case of non-ionic surfactants, the dynamic transition occurs at a fixed Ca, independently of the surfactant concentration, while for ionic surfactants, the dynamic transition depends on the concentration due to the existence of an electrostatic barrier. The control of physico-chemical parameters allowed us to elucidate the nature of the dynamic transition and to relate it to surface rheology.

Jérôme Delacotte; Lorraine Montel; Frédéric Restagno; Benoît Scheid; Benjamin Dollet; Howard A. Stone; Dominique Langevin; Emmanuelle Rio

2011-06-10T23:59:59.000Z

36

Phenomenological models of socioeconomic network dynamics  

Science Journals Connector (OSTI)

We study a general set of models of social network evolution and dynamics. The models consist of both a dynamics on the network and evolution of the network. Links are formed preferentially between “similar” nodes, where the similarity is defined by the particular process taking place on the network. The interplay between the two processes produces phase transitions and hysteresis, as seen using numerical simulations for three specific processes. We obtain analytic results using mean-field approximations, and for a particular case we derive an exact solution for the network. In common with real-world social networks, we find coexistence of high and low connectivity phases and history dependence.

George C. M. A. Ehrhardt; Matteo Marsili; Fernando Vega-Redondo

2006-09-13T23:59:59.000Z

37

Lattice dynamics and the phase transition from the cubic phase to the tetragonal phase in the LaMnO3 crystal within the polarizable-ion model  

Science Journals Connector (OSTI)

The paper reports on the results of ab initio calculations of the static and dynamic properties of the LaMnO3...crystal with a perovskite structure in the cubic, rhombohedral, and orthorhombic phases. The calcula...

V. I. Zinenko; M. S. Pavlovski?

2007-09-01T23:59:59.000Z

38

Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum  

E-Print Network (OSTI)

Ultrafast dynamics of the laser-induced solid-to-liquid phase transition in aluminum A thesis dynamics of the laser-induced solid-to-liquid phase transition in aluminum Eric Mazur Maria Kandyla Abstract This dissertation reports the ultrafast dynamics of aluminum during the solid-to- liquid phase

Mazur, Eric

39

Predictive Models of Forest Dynamics  

Science Journals Connector (OSTI)

...currently highly uncertain (Fig. 1), making vegetation dynamics one of the largest sources of uncertainty in Earth system models. Reducing this uncertainty requires work on several fronts. For example, physiological parameters need to be...

Drew Purves; Stephen Pacala

2008-06-13T23:59:59.000Z

40

Fluctuation effects in first-order phase transitions: Theory and model for martensitic transformations  

Science Journals Connector (OSTI)

We discuss central questions in weak, first-order structural transitions by means of a magnetic analog model. A theory including fluctuation effects is developed for the model, showing a dynamical response with softening, fading modes and a growing central peak. The model is also analyzed by a two-dimensional Monte Carlo simulation, showing clear precursor phenomena near the first-order transition and spontaneous nucleation. The kinetics of the domain growth is studied and found to be exceedingly slow. The results are applicable for martensitic transformations and structural surface-reconstructive transitions.

Per-Anker Lindgrd and Ole G. Mouritsen

1990-01-01T23:59:59.000Z

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.


41

How does dissipation affect the transition from static to dynamic macroscopic friction?  

E-Print Network (OSTI)

Description of the transitional process from a static to a dynamic frictional regime is a fundamental problem of modern physics. Previously we developed a model based on the well-known Frenkel-Kontorova model to describe dry macroscopic friction. Here this model has been modified to include the effect of dissipation in derived relations between the kinematic and dynamic parameters of a transition process. The main (somewhat counterintuitive) result is a demonstration that the rupture (i.e. detachment front) velocity of the slip pulse which arises during the transition does not depend on friction. The only parameter (besides the elastic and plastic properties of the medium) controlling the rupture velocity is the spatial distribution of the shear to normal stress ratio. In contrast to the rupture velocity, the slip velocity does depend on friction. The model we have developed describes these processes over a wide range of rupture and slip velocities (up to 7 orders of magnitude) allowing, in particular, the co...

Gershenzon, Naum I; Skinner, Thomas

2014-01-01T23:59:59.000Z

42

Ratcheted molecular-dynamics simulations identify efficiently the transition state of protein folding  

E-Print Network (OSTI)

The atomistic characterization of the transition state is a fundamental step to improve the understanding of the folding mechanism and the function of proteins. From a computational point of view, the identification of the conformations that build out the transition state is particularly cumbersome, mainly because of the large computational cost of generating a statistically-sound set of folding trajectories. Here we show that a biasing algorithm, based on the physics of the ratchet-and-pawl, can be used to identify efficiently the transition state. The basic idea is that the algorithmic ratchet exerts a force on the protein when it is climbing the free-energy barrier, while it is inactive when it is descending. The transition state can be identified as the point of the trajectory where the ratchet changes regime. Besides discussing this strategy in general terms, we test it within a protein model whose transition state can be studied independently by plain molecular dynamics simulations. Finally, we show its power in explicit-solvent simulations, obtaining and characterizing a set of transition--state conformations for ACBP and CI2.

Guido Tiana; Carlo Camilloni

2012-07-05T23:59:59.000Z

43

Glass transition line in C60: a mode-coupling/molecular-dynamics study  

E-Print Network (OSTI)

We report a study of the mode-coupling theory (MCT) glass transition line for the Girifalco model of C60 fullerene. The equilibrium static structure factor of the model, the only required input for the MCT calculations, is provided by molecular dynamics simulations. The glass transition line develops inside the metastable liquid-solid coexistence region and extends down in temperature, terminating on the liquid sideof the metastable portion of the liquid-vapor binodal. The vitrification locus does not show re-entrant behavior. A comparison with previous computer simulation estimates of the location of the glass line suggests that the theory accurately reproduces the shape of the arrest line in the density-temperature plane. The theoretical HNC and MHNC structure factors (and consequently the corresponding MCT glass line) compare well with the numerical counterpart. These evidences confirm the conclusion drawn in previous works about the existence of a glassy phase for the fullerene model at issue.

D. Costa; R. Ruberto; F. Sciortino; M. C. Abramo; C. Caccamo

2007-03-22T23:59:59.000Z

44

Model system for slow dynamics  

Science Journals Connector (OSTI)

Systems whose dynamics are described by a quasilogarithmic or stretched-exponential time dependence are usually fitted by models which use disorder to create a distribution of relaxation times. Here we describe a model which decays slowly towards equilibrium but does not require disorder to provide the slow dynamics. The model consists of a spin system with the spins interacting via the dipole-dipole interaction. The model is able to replicate the more pronounced features observed in the magnetization decay of magnetic systems and high-temperature superconductors.

D. K. Lottis; R. M. White; E. Dan Dahlberg

1991-07-15T23:59:59.000Z

45

Agent-Based Modeling and Simulation for Hydrogen Transition Analysis  

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

Presentation on Agent-Based Modeling and Simulation for Hydrogen Transition Analysis given by Marianne Mintz of ANL during the DOE Hydrogen Transition Analysis Workshop on January 26, 2006.

46

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

47

Development of a Dynamic DOE Calibration Model  

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

A dynamic heavy duty diesel engine model was developed. The model can be applied for calibration and control system optimization.

48

Ising model of a glass transition  

Science Journals Connector (OSTI)

Numerical simulations by Tanaka and co-workers indicate that glass-forming systems of moderately polydisperse hard-core particles, in both two and three dimensions, exhibit diverging correlation lengths. These correlations are described by Ising-like critical exponents, and are associated with diverging, Vogel-Fulcher-Tamann, structural relaxation times. Related simulations of thermalized hard disks indicate that the curves of pressure versus packing fraction for different polydispersities exhibit a sequence of transition points, starting with a liquid-hexatic transition for the monodisperse case, and crossing over with increasing polydispersity to glassy, Ising-like critical points. I propose to explain these observations by assuming that glass-forming fluids contain twofold degenerate, locally ordered clusters of particles, similar to the two-state systems that have been invoked to explain other glassy phenomena. This paper starts with a brief statistical derivation of the thermodynamics of thermalized, hard-core particles. It then discusses how a two-state, Ising-like model can be described within that framework in terms of a small number of statistically relevant, internal state variables. The resulting theory agrees accurately with the simulation data. I also propose a rationale for the observed relation between the Ising-like correlation lengths and the Vogel-Fulcher-Tamann formula.

J. S. Langer

2013-07-17T23:59:59.000Z

49

A Blended Soundproof-to-Compressible Numerical Model for Small- to Mesoscale Atmospheric Dynamics  

Science Journals Connector (OSTI)

A blended model for atmospheric flow simulations is introduced that enables seamless transition from fully compressible to pseudo-incompressible dynamics. The model equations are written in nonperturbation form and integrated using a well-balanced ...

Tommaso Benacchio; Warren P. O’Neill; Rupert Klein

2014-12-01T23:59:59.000Z

50

Dynamics of Subcritical Bubbles in First Order Phase Transition  

E-Print Network (OSTI)

We derivate the Langevin and the Fokker-Planck equations for the radius of $O(3)$-symmetric subcritical bubbles as a phenomenological model to treat thermal fluctuation. The effect of thermal noise on subcritical bubbles is examined. We find that the fluctuation-dissipation relation holds and that in the high temperature phase the system settles down rapidly to the thermal equilibrium state even if it was in a nonequilibrium state initially. We then estimate the typical size of subcritical bubbles as well as the amplitude of fluctuations on that scale. We also discuss their implication to the electroweak phase transition.

Tetsuya Shiromizu; Masahiro Morikawa; Jun'ichi Yokoyama

1995-09-05T23:59:59.000Z

51

System Transition: Dynamics of Change in the US Air TransportationSystem  

E-Print Network (OSTI)

System Transition: Dynamics of Change in the US Air TransportationSystem by Aleksandra L Education Committee #12;#12;System Transition: Dynamics of Change in the US Air Transportation System of the requirements for the degree of Doctor of Philosophy in Technology, Management, and Policy Abstract The US Air

de Weck, Olivier L.

52

The roughening transition of crystal surfaces. II. Experiments on static and dynamic properties  

E-Print Network (OSTI)

369 The roughening transition of crystal surfaces. II. Experiments on static and dynamic properties near the first roughening transition of hcp 4He F. Gallet, S. Balibar and E. Rolley Groupe de Physique experimental knowledge about the roughening transition of (0001) interfaces of hcp 4He crystals, at TR = 1.28 K

Paris-Sud XI, Université de

53

The roughening transition of crystal surfaces. I. Static and dynamic renormalization theory,  

E-Print Network (OSTI)

353 The roughening transition of crystal surfaces. I. Static and dynamic renormalization theory. Abstract. 2014 The renormalization approach to the roughening transition is reconsidered, both in a static appears, which must be compared to the correlation length 03BE. As a result, the roughening transition

Boyer, Edmond

54

Dynamical model of Ising spins  

Science Journals Connector (OSTI)

A two-dimensional dynamical model of Ising spins is introduced. Since we were not able to define energy in our system, we introduced an object called the disagreement function. This function controls the dynamics—minimizing it locally we decide upon spin flipping. Amazingly, local minimization of the disagreement function can lead to an increase of its global value. We present the phase diagram of the system and show that exactly the same initial conditions can lead the system to one of several, completely different final steady states.

Katarzyna Sznajd-Weron

2004-09-30T23:59:59.000Z

55

Assessing resilience and state-transition models with historical records of cheatgrass Bromus tectorum  

E-Print Network (OSTI)

Assessing resilience and state-transition models with historical records of cheatgrass Bromus. Bestelmeyer2 and X. Ben Wu1 1 Department of Ecosystem Science and Management, Texas A&M University, 2138 TAMU. This requires management frameworks that can assess ecosystem dynamics, both within and between alternative

56

Multi-disciplinary development of state and transition models  

E-Print Network (OSTI)

Multi-disciplinary development of state and transition models An Example from Northwestern Colorado and Transition Models: A Road Map to Ecological Change #12;STMs also help us learn · Tacit explicit knowledge Adaptive Management Cycle Grantham et al. 2010 Front. Ecol. Environment #12;Study Area: Elkhead Watershed

57

The nature of the continuous nonequilibrium phase transition of Axelrod's model  

E-Print Network (OSTI)

Axelrod's model differs from other models of opinion dynamics because it accounts for homophily and in a square lattice it exhibits culturally homogeneous as well as culturally fragmented absorbing configurations. In the case the agents are characterized by $F=2$ cultural features and each feature assumes $k$ traits drawn from a Poisson distribution of parameter $q$ these regimes are separated by a continuous transition at $q_c \\approx 3.15$. Here we show that the mean density of cultural domains is an order parameter of the model and that the phase transition is characterized by the critical exponents $\\beta = 1/2$ and $\

Peres, Lucas R

2014-01-01T23:59:59.000Z

58

Comment on "Dynamics of Weak First Order Phase Transitions"  

E-Print Network (OSTI)

We comment on an earlier paper of M. Gleiser, regarding mechanisms of first-order phase transitions.

G. Harris; G. Jungman

1995-11-08T23:59:59.000Z

59

Renormalisation group for depinning transition ind=2 ising models  

Science Journals Connector (OSTI)

We develop a position space renormalisation group (RG) method to study generalised depinning transition in two-dimensional Ising models. The treatment encompasses (i) the original model for depinning invented by ...

D. N. Mihajlovi?; N. M. Švraki?

1983-01-01T23:59:59.000Z

60

A spinning thermometer to monitor microwave heating and glass transitions in dynamic  

E-Print Network (OSTI)

A spinning thermometer to monitor microwave heating and glass transitions in dynamic nuclear in a static rotor by inserting a platinum thermometer. The accuracy is better than Ã? 0.9 K, even

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

Stochastic dynamo model for subcritical transition Sergei Fedotov,1,  

E-Print Network (OSTI)

Stochastic dynamo model for subcritical transition Sergei Fedotov,1, * Irina Bashkirtseva,2 and Lev a "slow" variable that determines the global evolution of the non-normal -dynamo system in the subcritical,2 . It explains the subcritical transition to turbulence when the laminar flow changes to a turbulent regime

Fedotov, Sergei

62

Modelling and Numerical Simulation of Liquid-Vapor Phase Transition  

E-Print Network (OSTI)

of pressurized water reactors in the nuclear industry. Indeed, understanding the triggering of boiling crisis, temperatures and chemical potentials, which enables dynamic generation of two-phase interfaces within a pure is a critical safety issue for the nuclear industry: when the transition occurs from nucleate boiling to film

Faccanoni, Gloria

63

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

64

Workforce Transition Modeling Environment user`s guide  

SciTech Connect

The Pacific Northwest Laboratory (PNL) was tasked by the US Department of Energy Albuquerque Field Office (DOE-AL) to develop a workforce assessment and transition planning tool to support integrated decision making at a single DOE installation. The planning tool permits coordinated, integrated workforce planning to manage growth, decline, or transition within a DOE installation. The tool enhances the links and provides commonality between strategic, programmatic, and operations planners and human resources. Successful development and subsequent complex-wide implementation of the model also will facilitate planning at the national level by enforcing a consistent format on data that are now collected by installations in corporate-specific formats that are not amenable to national-level analyses. The workforce assessment and transition planning tool, the Workforce Transition Modeling Environment (WFTME), consists of two components: the Workforce Transition Model and the Workforce Budget Constraint Model. The Workforce Transition Model, the preponderant of the two, assists decision makers identify and evaluate alternatives for transitioning the current workforce to meet the skills required to support projected workforce requirements. The Workforce Budget Constraint Model helps estimate the number of personnel that will be affected by a given workforce budget increase or decrease and assists in identifying how the corresponding hirings or layoffs should be distributed across the Common Occupation Classification System (COCS) occupations. This user`s guide describes the use and operation of the WFTME. This includes the functions of modifying data and running models, interpreting output reports, and an approach for using the WFTME to evaluate various workforce transition scenarios.

Stahlman, E.J.; Oens, M.A.; Lewis, R.E.

1993-10-01T23:59:59.000Z

65

Implementing SPC in a Simulation Model for Manufacturing Transitions  

E-Print Network (OSTI)

- ~(~-;::;: Implementing SPC in a Simulation Model for Manufacturing Transitions Harriet Black of resources utilization, and optimization of system re- sources. Although discrete-event simulation modeling the design and development of an integrated SPC and simulation model. Figure 1 shows a screen snapshot

Nembhard, Harriet Black

66

Development of one-equation transition/turbulence models  

SciTech Connect

This paper reports on the development of a unified one-equation model for the prediction of transitional and turbulent flows. An eddy viscosity--transport equation for nonturbulent fluctuation growth based on that proposed by Warren and Hassan is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittency function based on the work of Dhawan and Narasimha. The model predicts both the onset and extent of transition. Low-speed test cases include transitional flow over a flat plate, a single element airfoil, and a multi-element airfoil in landing configuration. High-speed test cases include transitional Mach 3.5 flow over a 5{degree} cone and Mach 6 flow over a flared-cone configuration. Results are compared with experimental data, and the grid-dependence of selected predictions is analyzed.

Edwards, J.R.; Roy, C.J.; Blottner, F.G.; Hassan, H.A.

2000-01-14T23:59:59.000Z

67

Multiple high-temperature transitions driven by dynamical structures in NaI  

SciTech Connect

Multiple, consecutive high-temperature transitions in NaI involving dynamical order and/or localization in the energy-momentum spectrum but not in the average crystal structure are revealed by lattice dynamics, x-ray lattice spacing, and heat capacity measurements. Distinctive energy-momentum patterns and lattice distortions indicate dynamical structures forming within randomly stacked planes, rather than the isolated point-defect-like intrinsic localized modes predicted. Transition entropies are accounted for by vibrational entropy changes and the transition enthalpies are explained by the strain energy of forming stacking-fault-like planar distortions deduced from x-ray diffraction peak shifts. The vibrational entropy of the dynamical structures stabilizes surrounding elastic distortions.

Manley, Michael E [ORNL; Jeffries, Jason R [ORNL; Lee, Hohyun [Santa Clara University, California; Zabalegui, Aitor [Santa Clara University, California; Abernathy, Douglas L [ORNL

2014-01-01T23:59:59.000Z

68

Rotational dynamics in the plastic-crystal phase of ethanol: Relevance for understanding the dynamics during the structural glass transition  

Science Journals Connector (OSTI)

The reorientational dynamics within the rotationally disordered cubic plastic phase of solid ethanol is investigated by means of the concurrent use of computer molecular dynamics and quasielastic neutron scattering. Motions involving widely different time scales are shown to take place above the calorimetric “glass transition” which is centered at Tg?97?K. These correspond to well-defined reorientations belonging to the cubic point group. The dynamics of this solid exhibits features remarkably close to those of the supercooled liquid that can exist at the same temperature. Such similitude of dynamic behavior serves to provide some clues for the understanding of the nature of molecular motions at temperatures close to the canonical liquid?glass transition.

A. Criado; M. Jiménez-Ruiz; C. Cabrillo; F. J. Bermejo; R. Fernández-Perea; H. E. Fischer; F. R. Trouw

2000-05-01T23:59:59.000Z

69

Vanishing amplitude of backbone dynamics causes a true protein dynamical transition: H2 NMR studies on perdeuterated C-phycocyanin  

Science Journals Connector (OSTI)

Using a combination of H2 nuclear magnetic resonance (NMR) methods, we study internal rotational dynamics of the perdeuterated protein C-phycocyanin (CPC) in dry and hydrated states over broad temperature and dynamic ranges with high angular resolution. Separating H2 NMR signals from methyl deuterons, we show that basically all backbone deuterons exhibit highly restricted motion occurring on time scales faster than microseconds. The amplitude of this motion increases when a hydration shell exists, while it decreases upon cooling and vanishes near 175 K. We conclude that the vanishing of the highly restricted motion marks a dynamical transition, which is independent of the time window and of a fundamental importance. This conclusion is supported by results from experimental and computational studies of the proteins myoglobin and elastin. In particular, we argue based on findings in molecular dynamics simulations that the behavior of the highly restricted motion of proteins at the dynamical transition resembles that of a characteristic secondary relaxation of liquids at the glass transition, namely the nearly constant loss. Furthermore, H2 NMR studies on perdeuterated CPC reveal that, in addition to highly restricted motion, small fractions of backbone segments exhibit weakly restricted dynamics when temperature and hydration are sufficiently high.

Kerstin Kämpf; Beke Kremmling; Michael Vogel

2014-03-17T23:59:59.000Z

70

HyPro: Modeling the Hydrogen Transition  

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

Presentation by Brian James of Directed Technologies at the Joint Meeting on Hydrogen Delivery Modeling and Analysis, May 8-9, 2007

71

Controlling the dynamics of quantum mechanical systems sustaining dipole-forbidden transitions via optical nanoantennas  

Science Journals Connector (OSTI)

We suggest to excite dipole-forbidden transitions in quantum mechanical systems by using appropriately designed optical nanoantennas. The antennas are tailored such that their near field contains sufficiently strong contributions of higher-order multipole moments. The strengths of these moments exceed their free-space analogs by several orders of magnitude. The impact of such excitation enhancement is exemplarily investigated by studying the dynamics of a three-level system. It decays upon excitation by an electric quadrupole transition via two electric dipole transitions. Since one dipole transition is assumed to be radiative, the enhancement of this emission serves as a figure of merit. Such self-consistent treatment of excitation, emission, and internal dynamics as developed in this contribution is the key to predict any observable quantity. The suggested scheme may represent a blueprint for future experiments and will find many obvious spectroscopic and sensing applications.

Robert Filter; Stefan Mühlig; Toni Eichelkraut; Carsten Rockstuhl; Falk Lederer

2012-07-05T23:59:59.000Z

72

Dynamic competition model for construction contractors  

E-Print Network (OSTI)

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...

Kim, Hyung Jin

2012-06-07T23:59:59.000Z

73

Conceptual aircraft dynamics from inverse aircraft modeling  

E-Print Network (OSTI)

This thesis presents a method of construe' ting a nonlinear dynamics model of a theoretical aircraft from the nonlinear batch simulation of an existing aircrew This method provides control law designers with a method of fabricating nonlinear models...

Ziegler, Gregory E

1999-01-01T23:59:59.000Z

74

A Dynamic Model of Thundercloud Electric Fields  

Science Journals Connector (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

75

A Robust Model Control for Dynamic Systems  

Science Journals Connector (OSTI)

Analytical methods of polynomial algebra, heuristic techniques, and digital modeling are used to study the robustness domain of linear dynamic systems with model “input–output” controllers as a function of the mutual locations of zeros ...

S. V. Tararykin; V. V. Tyutikov

2002-05-01T23:59:59.000Z

76

Dynamic LES Modeling of a Diurnal Cycle  

Science Journals Connector (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

77

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect

Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation.

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

2006-06-18T23:59:59.000Z

78

Calcium Dynamics in Large Neuronal Models  

E-Print Network (OSTI)

Chapter 6 Calcium Dynamics in Large Neuronal Models ERIK DE SCHUTTER and PAUL SMOLEN 6.1 Introduction Calcium is an important intracellular signaling molecule with rapid e ect on the kinetics of many active membrane model that includes Ca2+ dynamics, one is faced with a feedback loop: the Ca2+-activated

De Schutter, Erik

79

Growing Dynamical Facilitation on Approaching the Random Pinning Colloidal Glass Transition  

E-Print Network (OSTI)

Despite decades of research, it remains to be established whether the transformation of a liquid into a glass is fundamentally thermodynamic or dynamic in origin. While observations of growing length scales are consistent with thermodynamic perspectives like the Random First-Order Transition theory (RFOT), the purely dynamic approach of the Dynamical Facilitation (DF) theory lacks experimental validation. Further, for glass transitions induced by randomly freezing a subset of particles in the liquid phase, simulations support the predictions of RFOT, whereas the DF theory remains unexplored. Here, using video microscopy and holographic optical tweezers, we show that dynamical facilitation in a colloidal glass-forming liquid unambiguously grows with density as well as the fraction of pinned particles. In addition, we show that heterogeneous dynamics in the form of string-like cooperative motion, which is believed to be consistent with RFOT, emerges naturally within the framework of facilitation. Most importantly, our findings demonstrate that a purely dynamic origin of the glass transition cannot be ruled out.

Shreyas Gokhale; K. Hima Nagamanasa; Rajesh Ganapathy; A. K. Sood

2014-06-25T23:59:59.000Z

80

Very Large System Dynamics Models - Lessons Learned  

SciTech Connect

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

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

A Simplified Model of Phase Transition in Amorphous Antiferromagnets. III: XY and Heisenberg Spins  

Science Journals Connector (OSTI)

......order-disorder transition of chirality...Heisenberg model, phase transition does not occur...which magnetic ions distribute randomly...structure of magnetic ions and the strong...the nature of phase transition (if any) and......

Hikaru Kawamura

1985-02-01T23:59:59.000Z

82

Dynamic Transitions in Pure Ising Magnets under Pulsed and Oscillating Fields  

E-Print Network (OSTI)

Dynamic Transitions in Pure Ising Magnets under Pulsed and Oscillating Fields Bikas K. Chakrabarti. Abstract Response of pure Ising systems to time-dependent external magnetic #28;elds, like pulsed case is that of an Ising ferromagnet below its static critical temperature, when it is perturbed

Usadel, K. D.

83

Transition dynamics for multi-pulsing in mode-locked lasers  

E-Print Network (OSTI)

laser," Opt. Lett. 23, 123-125 (1998). 5. M. E. Fermann and J. D. Minelly, "Cladding-pumped passiveTransition dynamics for multi-pulsing in mode-locked lasers Brandon G. Bale1, Khanh Kieu2, J.bale@aston.ac.uk Abstract: We consider experimentally and theoretically a refined parameter space in a laser system near

Kieu, Khanh

84

Glass transition and alpha-relaxation dynamics of thin films of labeled polystyrene  

E-Print Network (OSTI)

The glass transition temperature and relaxation dynamics of the segmental motions of thin films of polystyrene labeled with a dye, 4-[N-ethyl-N-(hydroxyethyl)]amino-4-nitraozobenzene (Disperse Red 1, DR1) are investigated using dielectric measurements. The dielectric relaxation strength of the DR1-labeled polystyrene is approximately 65 times larger than that of the unlabeled polystyrene above the glass transition, while there is almost no difference between them below the glass transition. The glass transition temperature of the DR1-labeled polystyrene can be determined as a crossover temperature at which the temperature coefficient of the electric capacitance changes from the value of the glassy state to that of the liquid state. The glass transition temperature of the DR1-labeled polystyrene decreases with decreasing film thickness in a reasonably similar manner to that of the unlabeled polystyrene thin films. The dielectric relaxation spectrum of the DR1-labeled polystyrene is also investigated. As thickness decreases, the $\\alpha$-relaxation time becomes smaller and the distribution of the $\\alpha$-relaxation times becomes broader. These results show that thin films of DR1-labeled polystyrene are a suitable system for investigating confinement effects of the glass transition dynamics using dielectric relaxation spectroscopy.

Rodney D. Priestley; Linda J. Broadbelt; John M. Torkelson; Koji Fukao

2008-01-05T23:59:59.000Z

85

Effect of flow rate of ethanol on growth dynamics of VA-SWNT -Transition from no-flow CVD to normal ACCVD  

E-Print Network (OSTI)

Effect of flow rate of ethanol on growth dynamics of VA-SWNT - Transition from no-flow CVD a growth model [2]. In this study, the flow rate of ethanol during the CVD was controlled precisely. Figure 1 shows the growth curve of VA-SWNT film for various ethanol flow rates. In the figure, "No

Maruyama, Shigeo

86

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/

87

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

88

Single tensionless transition in the Laplacian roughening model  

E-Print Network (OSTI)

We report large scale Monte Carlo simulations of the equilibrium discrete Laplacian roughening (dLr) model, originally introduced as the simplest one accommodating the hexatic phase in two-dimensional melting. The dLr model is also relevant to surface roughening in molecular beam epitaxy (MBE). Our data suggest a single phase transition, possibly of the Kosterlitz-Thouless type, between a flat low-temperature phase and a rough, tensionless, high-temperature phase. Thus, earlier conclusions on the order of the phase transition and on the existence of a hexatic phase are seen as due to finite size effects, the phase diagram of the dLr model being similar to that of a continuum analog previously formulated in the context of surface growth by MBE.

Juan Jesus Ruiz-Lorenzo; Esteban Moro; Rodolfo Cuerno

2006-01-23T23:59:59.000Z

89

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)

90

Model Validation with Hybrid Dynamic Simulation  

SciTech Connect

Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation. A few methods to define model quality indices have been proposed to quantify model error for model validation criteria development.

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

2006-06-22T23:59:59.000Z

91

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

Science Journals Connector (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.

Peng-Tang Qi and Wen-Shan Duan

2011-09-22T23:59:59.000Z

92

Can xenon in water inhibit ice growth? Molecular dynamics of phase transitions in water$-$Xe system  

E-Print Network (OSTI)

Motivated by recent experiments showing the promise of noble gases as cryoprotectants, we perform molecular dynamics modeling of phase transitions in water with xenon under cooling. We study the structure and dynamics of xenon water solution as a function of temperature. Homogeneous nucleation of clathrate hydrate phase is observed and characterized. As the temperature is further reduced we observe hints of dissociation of clathrate due to stronger hydrophobic hydration, pointing towards a possible instability of clathrate at cryogenic temperatures and conversion to an amorphous phase comprised of "xenon + hydration shell" Xe$\\cdot$(H$_{2}$O)$_{21.5}$ clusters. Simulations of ice$-$xenon solution interface in equilibrium and during ice growth reveal the effects of xenon on the ice$-$liquid interface, where adsorbed xenon causes roughening of ice surface but does not preferentially form clathrate. These results provide evidence against the ice-blocker mechanism of xenon cryoprotection.

Vasilii I. Artyukhov; Alexander Yu. Pulver; Alex Peregudov; Igor Artyuhov

2014-07-11T23:59:59.000Z

93

Sign relation between the static and dynamic contributions to the one-photon f?f transition amplitude  

Science Journals Connector (OSTI)

The sign rules for static and dynamic contributions to the one-photon electric dipole transition amplitude are presented. The discussion is based on the third-order electron correlation approach introduced previously. The final conclusions are deduced from a structural-factor-independent analysis of numerical results of exact ab initio calculations. It has been demonstrated that the signs of certain contributions are fixed for all ions across the lanthanide series. This rule has been also observed for angular and radial terms of effective operators defined within each model and at a given order of perturbation expansion. The main conclusion of the present analysis states that the third-order electron correlation static and dynamic contributions are always of opposite signs in relation to the counterparts determined at the second order.

Lidia Smentek-Mielczarek

1993-10-01T23:59:59.000Z

94

A stochastic evolutionary model for survival dynamics  

E-Print Network (OSTI)

The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in different contexts. Here we propose a generative model to capture the essential dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. In our model, the only implicit assumption made is that the longer an actor has been in the system, the more likely it is to have failed. We derive a power-law distribution for the process and provide preliminary empirical evidence for the validity of the model from two well-known survival analysis data sets.

Fenner, Trevor; Loizou, George

2014-01-01T23:59:59.000Z

95

Modeling Internet Topology Dynamics Hamed Haddadi  

E-Print Network (OSTI)

graphs. Generation of the topology of the Internet calls for a model that achieves a good balance betweenModeling Internet Topology Dynamics Hamed Haddadi University College London Steve Uhlig Delft and inference, there still exists ambiguity about the real nature of the Internet AS and router level topol- ogy

Haddadi, Hamed

96

Dynamic modeling of IGCC power plants  

Science Journals Connector (OSTI)

Integrated Gasification Combined Cycle (IGCC) power plants are an effective option to reduce emissions and implement carbon-dioxide sequestration. The combination of a very complex fuel-processing plant and a combined cycle power station leads to challenging problems as far as dynamic operation is concerned. Dynamic performance is extremely relevant because recent developments in the electricity market push toward an ever more flexible and varying operation of power plants. A dynamic model of the entire system and models of its sub-systems are indispensable tools in order to perform computer simulations aimed at process and control design. This paper presents the development of the lumped-parameters dynamic model of an entrained-flow gasifier, with special emphasis on the modeling approach. The model is implemented into software by means of the Modelica language and validated by comparison with one set of data related to the steady operation of the gasifier of the Buggenum power station in the Netherlands. Furthermore, in order to demonstrate the potential of the proposed modeling approach and the use of simulation for control design purposes, a complete model of an exemplary IGCC power plant, including its control system, has been developed, by re-using existing models of combined cycle plant components; the results of a load dispatch ramp simulation are presented and shortly discussed.

F. Casella; P. Colonna

2012-01-01T23:59:59.000Z

97

Viscosity model for gases in the transition regime  

Science Journals Connector (OSTI)

We have studied a model of tangential viscosity of a fluid in which high-order spatial derivatives of the velocity are taken into account. The model indicates that for a gas in the transition regime, and within a range of boundary conditions, the tangential stress presents an oscillatory dependence on the density. An experiment designed to detect these oscillations was done with helium at constant temperature T=294°K and varying the pressure within the range 0.5-50 mTorr. The results were found to be in good agreement with the oscillations predicted by our model when the spatial derivative of the fluid velocity near the boundaries was close to zero. From the separation in density between these oscillations, it is possible to obtain an independent measurement of the atomic mean cross section for helium. This method makes specific use of the way the viscosity oscillates with the density in the transition regime instead of using the value that the viscosity takes in the continuous regime. The good agreement between our measurements of the cross section and the values that have been obtained by other methods gives an indication of the validity of the proposed model.

D. Moronta and M. García-Sucre

1978-08-01T23:59:59.000Z

98

Modeling emotional dynamics : currency versus field.  

SciTech Connect

Randall Collins has introduced a simplified model of emotional dynamics in which emotional energy, heightened and focused by interaction rituals, serves as a common denominator for social exchange: a generic form of currency, except that it is active in a far broader range of social transactions. While the scope of this theory is attractive, the specifics of the model remain unconvincing. After a critical assessment of the currency theory of emotion, a field model of emotion is introduced that adds expressiveness by locating emotional valence within its cognitive context, thereby creating an integrated orientation field. The result is a model which claims less in the way of motivational specificity, but is more satisfactory in modeling the dynamic interaction between cognitive and emotional orientations at both individual and social levels.

Sallach, D .L.; Decision and Information Sciences; Univ. of Chicago

2008-08-01T23:59:59.000Z

99

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

100

Phase transitions in high energy heavy ion collisions within fluid dynamics  

E-Print Network (OSTI)

Recent advances in Fluid Dynamical modeling of heavy ion collisions are presented, with particular attention to mesoscopic systems, QGP formation in the pre FD regime and QGP hadronization coinciding with the final freeze-out.

L. P. Csernai; Cs. Anderlik; V. Magas

2000-10-06T23:59:59.000Z

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
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101

Phase transitions in a reaction-diffusion model on a line with boundaries  

SciTech Connect

A one-dimensional model on a line of length L is investigated, which involves particle diffusion as well as single particle annihilation. There are also creation and annihilation at the boundaries. The static and dynamical behaviors of the system are studied. It is seen that the system could exhibit a dynamical phase transition. For small drift velocities, the relaxation time does not depend on the absorption rates at the boundaries. This is the fast phase. For large velocities, the smaller of the absorption rates at boundaries enter the relaxation rate and makes it longer. This is the slow phase. Finally, the effect of a random particle creation in the bulk is also investigated.

Khorrami, Mohammad, E-mail: mamwad@mailaps.org; Aghamohammadi, Amir, E-mail: mohamadi@alzahra.ac.ir [Department of Physics, Alzahra University, Tehran 19938-93973 (Iran, Islamic Republic of)] [Department of Physics, Alzahra University, Tehran 19938-93973 (Iran, Islamic Republic of)

2014-03-15T23:59:59.000Z

102

Electrical Neutrality and Symmetry Restoring Phase Transitions at High Density in a Two-Flavor Nambu-Jona-Lasinio Model  

E-Print Network (OSTI)

A general research on chiral symmetry restoring phase transitions at zero temperature and finite chemical potentials under electrical neutrality condition has been conducted in a Nambu-Jona-Lasinio model to describe two-flavor normal quark matter. Depending on that $m_0/\\Lambda$, the ratio of dynamical quark mass in vacuum and the 3D momentum cutoff in the loop integrals, is less or greater than 0.413, the phase transition will be second or first order. A complete phase diagram of $u$ quark chemical potential versus $m_0$ is given. With the electrical neutrality constraint, the region where second order phase transition happens will be wider than the one without electrical neutrality limitation. The results also show that, for the value of $m_0/\\Lambda$ from QCD phenomenology, the phase transition must be first order.

Xiao-Ming Wang; Bang-Rong Zhou

2007-06-01T23:59:59.000Z

103

Hysteretic transitions in the Kuramoto model with inertia  

E-Print Network (OSTI)

We report finite size numerical investigations and mean field analysis of a Kuramoto model with inertia for fully coupled and diluted systems. In particular, we examine for a Gaussian distribution of the frequencies the transition from incoherence to coherence for increasingly large system size and inertia. For sufficiently large inertia the transition is hysteretic and within the hysteretic region clusters of locked oscillators of various sizes and different levels of synchronization coexist. A modification of the mean field theory developed by Tanaka, Lichtenberg, and Oishi [Physica D, 100 (1997) 279] allows to derive the synchronization profile associated to each of these clusters. We have also investigated numerically the limits of existence of the coherent and of the incoherent solutions. The minimal coupling required to observe the coherent state is largely independent of the system size and it saturates to a constant value already for moderately large inertia values. The incoherent state is observable up to a critical coupling whose value saturates for large inertia and for finite system sizes, while in the thermodinamic limit this critical value diverges proportionally to the mass. By increasing the inertia the transition becomes more complex, and the synchronization occurs via the emergence of clusters of whirling oscillators. The presence of these groups of coherently drifting oscillators induces oscillations in the order parameter. We have shown that the transition remains hysteretic even for randomly diluted networks up to a level of connectivity corresponding to few links per oscillator. Finally, an application to the Italian high-voltage power grid is reported, which reveals the emergence of quasi-periodic oscillations in the order parameter due to the simultaneous presence of many competing whirling clusters.

Simona Olmi; Adrian Navas; Stefano Boccaletti; Alessandro Torcini

2014-06-14T23:59:59.000Z

104

Rangeland Ecology & Management Spatially-explicit representation of state-and-transition models  

E-Print Network (OSTI)

Rangeland Ecology & Management Spatially-explicit representation of state-and-transition models state-and-transition models (STMs) to spatial units is a valuable management tool for structuring ground Manager® from Aries Systems Corporation #12;1 Spatially-Explicit Representation of State-and-Transition

105

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

106

Modeling joint friction in structural dynamics.  

SciTech Connect

The presence of mechanical joints--typified by the lap joint--in otherwise linear structures has been accommodated in structural dynamics via ad hoc methods for a century. The methods range from tuning linear models to approximate non-linear behavior in restricted load ranges to various methods which introduce joint dissipation in a post-processing stage. Other methods, employing constitutive models for the joints are being developed and their routine use is on the horizon.

Segalman, Daniel Joseph

2005-05-01T23:59:59.000Z

107

Physics Reports 355 (2001) 235334 Quantum phase transitions and vortex dynamics in  

E-Print Network (OSTI)

Contents 1. Introduction 237 1.1. Josephson-junction arrays 237 1.2. Phase-number relation 238 1.3. Structure of the review 239 2. Quantum phase transitions 240 2.1. The model of a Josephson-junction array currents 313 4.2. The quantum Hall e ect 316 4.3. Quantum computation with Josephson junctions 317

108

An Extended Transition Energy Cost Model for Buses in Deep Submicron Technologies  

Science Journals Connector (OSTI)

In this paper we present and carefully analyze a transition energy cost model aimed for efficient power estimation of ... submicron buses. We derive an accurate transition energy cost matrix, scalable to buses of...

Peter Caputa; Henrik Fredriksson…

2004-01-01T23:59:59.000Z

109

Improving the transition modelling in hidden Markov models for ECG segmentation  

E-Print Network (OSTI)

Improving the transition modelling in hidden Markov models for ECG segmentation Benoît Frénay, Gaël/ELEC/DICE - Place du Levant, 3 1348 Louvain-la-Neuve, Belgium Abstract. The segmentation of ECG signal is a useful-dependent. Experiments show that both methods improve the results on pathological ECG signals. 1 Introduction Physicians

Verleysen, Michel

110

Complex-Dynamic Origin of Consciousness and the Critical Choice of Sustainability Transition  

E-Print Network (OSTI)

A quite general interaction process of a multi-component system is analysed by the extended effective potential method liberated from usual limitations of perturbation theory or integrable model. The obtained causally complete solution of the many-body problem reveals the phenomenon of dynamic multivaluedness, or redundance, of emerging, incompatible system realisations and dynamic entanglement of system components within each realisation. The ensuing concept of dynamic complexity (and related intrinsic chaoticity) is absolutely universal and can be applied to the problem of (natural and artificial) intelligence and consciousness that dynamically emerge now as a high enough, properly specified levels of unreduced complexity of a suitable interaction process. Emergent consciousness can be identified with the appearance of bound, permanently localised states in the multivalued brain dynamics from strongly chaotic states of unconscious intelligence, by analogy with classical behaviour emergence from quantum states at the lowest levels of complex world dynamics. We show that the main properties of this dynamically emerging consciousness (and intelligence, at the preceding complexity level) correspond to empirically derived properties of natural consciousness and obtain causally substantiated conclusions about their artificial realisation, including the fundamentally justified paradigm of genuine machine consciousness. This rigorously defined machine consciousness is different from both natural consciousness and any mechanistic, dynamically single-valued imitation of the latter. We use then the same, truly universal concept of complexity to derive equally rigorous conclusions about mental and social implications of this complex-dynamic consciousness concept, demonstrating its critical importance for further progress of science and civilisation.

Andrei P. Kirilyuk

2014-04-17T23:59:59.000Z

111

Dynamic model of hysteretic elastic systems  

Science Journals Connector (OSTI)

A model for the dynamical behavior of a hysteretic elastic system is introduced and studied numerically. This model consists of a chain of hysteretic elastic elements. Each elastic element is a spring with properties that depend on an Ising-like state variable having Brownian dynamics in an energy landscape with structure that is sensitive to the forces which the elastic element must support. A single elastic element is studied carefully, numerically in order to establish its basic behavior. A one dimensional chain of N=500 elastic elements, driven like a resonant bar, is studied numerically. The data from this study are analyzed by the methods employed in analyzing similar experimental data. The behavior of the numerical model compares well with the behavior of physical realizations of hysteretic elastic systems.

Barbara Capogrosso-Sansone and R. A. Guyer

2002-12-05T23:59:59.000Z

112

Development and validation of a transition model based on a mechanical approximation  

E-Print Network (OSTI)

A new 3D transition turbulence model, more accurate and faster than an empirical transition model, is proposed. The model is based on the calculation of the pre-transitional u'v' due to mean flow shear. The present transition model is fully described and verified against eight benchmark test cases. Computations are performed for the ERCOFTAC flat-plate T3A, T3C and T3L test cases. Further, the model is validated for bypass, cross-flow and separation induced transition and compared with empirical transition models. The model presents very good results for bypass transition under zero-pressure gradient and with pressure gradient flow conditions. Also the model is able to correctly predict separation induced transition. However, for very low speed and low free-stream turbulence intensity the model delays separation induced transition onset. The model also shows very good results for transition under complex cross-flow conditions in three-dimensional geometries. The 3D tested case was the 6:1 prolate-spheroid und...

Vizinho, R; Silvestre, M

2015-01-01T23:59:59.000Z

113

Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition  

E-Print Network (OSTI)

: http://scitation.aip.org/termsconditions. Downloaded to IP: 131.111.185.7 On: Thu, 09 Oct 2014 15:47:13 18Y. L. Iunin, Y. P. Kabanov, V. I. Nikitenko, X. M. Cheng, D. Clarke, O. A. Tretiakov, O. Tchernyshyov, A. J. Shapiro, R. D. Shull, and C. L. Chien... Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition A. Fernández-Pacheco, F. C. Ummelen, R. Mansell, D. Petit, J. H. Lee, H. J. M. Swagten, and R. P. Cowburn Citation: Applied Physics...

Fern ández-Pacheco, A.; Ummelen, F. C.; Mansell, R.; Petit, D.; Lee, J. H.; Swagten, H. J. M.; Cowburn, R. P.

2014-09-05T23:59:59.000Z

114

The dynamic radiation environment assimilation model (DREAM)  

SciTech Connect

The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.

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

2010-01-01T23:59:59.000Z

115

Environmentally induced Quantum Dynamical Phase Transition in the spin swapping operation  

E-Print Network (OSTI)

Quantum Information Processing relies on coherent quantum dynamics for a precise control of its basic operations. A swapping gate in a two-spin system exchanges the degenerate states |+,-> and |-,+>. In NMR, this is achieved turning on and off the spin-spin interaction b=\\Delta E that splits the energy levels and induces an oscillation with a natural frequency \\Delta E/\\hbar. Interaction of strength \\hbar/\\tau_{SE}, with an environment of neighboring spins, degrades this oscillation within a decoherence time scale \\tau_{\\phi}. While the experimental frequency \\omega and decoherence time \\tau_{\\phi} were expected to be roughly proportional to b/\\hbar and \\tau_{SE} respectively, we present here experiments that show drastic deviations in both \\omega and \\tau_{\\phi}. By solving the many spin dynamics, we prove that the swapping regime is restricted to \\Delta E \\tau_{SE} > \\hbar. Beyond a critical interaction with the environment the swapping freezes and the decoherence rate drops as 1/\\tau_{\\phi} \\propto (b/\\hbar)^2 \\tau_{SE}. The transition between quantum dynamical phases occurs when \\omega \\propto \\sqrt{(b/\\hbar)^{2}-(k/\\tau_{SE})^2} becomes imaginary, resembling an overdamped classical oscillator. Here, 0environment interaction, being 0 for isotropic and 1 for XY interactions. This critical onset of a phase dominated by the Quantum Zeno effect opens up new opportunities for controlling quantum dynamics.

Gonzalo Agustin Alvarez; Ernesto Pablo Danieli; Patricia Rebeca Levstein; Horacio Miguel Pastawski

2005-04-13T23:59:59.000Z

116

DYNAMICAL MODELING OF GALAXY MERGERS USING IDENTIKIT  

SciTech Connect

We present dynamical models of four interacting systems: NGC 5257/8, The Mice, the Antennae, and NGC 2623. The parameter space of the encounters are constrained using the Identikit model-matching and visualization tool. Identikit utilizes hybrid N-body and test particle simulations to enable rapid exploration of the parameter space of galaxy mergers. The Identikit-derived matches of these systems are reproduced with self-consistent collisionless simulations which show very similar results. The models generally reproduce the observed morphology and H I kinematics of the tidal tails in these systems with reasonable properties inferred for the progenitor galaxies. The models presented here are the first to appear in the literature for NGC 5257/8 and NGC 2623, and The Mice and the Antennae are compared with previously published models. Based on the assumed mass model and our derived initial conditions, the models indicate that the four systems are currently being viewed 175-260 Myr after first passage and cover a wide range of merger stages. In some instances there are mismatches between the models and the data (e.g., in the length of a tail); these are likely due to our adoption of a single mass model for all galaxies. Despite the use of a single mass model, these results demonstrate the utility of Identikit in constraining the parameter space for galaxy mergers when applied to real data.

Privon, G. C.; Evans, A. S. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Barnes, J. E. [Institute for Astronomy, University of Hawaii, at Manoa, Honolulu, HI (United States); Hibbard, J. E. [National Radio Astronomy Observatory, Charlottesville, VA 22904 (United States); Yun, M. S. [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Mazzarella, J. M. [NASA Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Armus, L.; Surace, J., E-mail: gcp8y@virginia.edu [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2013-07-10T23:59:59.000Z

117

Spatial perspectives in state-and-transition models: a missing link to land management?  

E-Print Network (OSTI)

REVIEW Spatial perspectives in state-and-transition models: a missing link to land management to select or justify management actions. State transitions are characteristi- cally heterogeneous in space transitions at each scale and that can be considered in empirical studies, STM narratives and management

118

The peptide-receptive transition state of MHC-1 molecules: Insight from structure and molecular dynamics  

SciTech Connect

MHC class I (MHC-I) proteins of the adaptive immune system require antigenic peptides for maintenance of mature conformation and immune function via specific recognition by MHC-I-restricted CD8(+) T lymphocytes. New MHC-I molecules in the endoplasmic reticulum are held by chaperones in a peptide-receptive (PR) transition state pending release by tightly binding peptides. In this study, we show, by crystallographic, docking, and molecular dynamics methods, dramatic movement of a hinged unit containing a conserved 3(10) helix that flips from an exposed 'open' position in the PR transition state to a 'closed' position with buried hydrophobic side chains in the peptide-loaded mature molecule. Crystallography of hinged unit residues 46-53 of murine H-2L(d) MHC-I H chain, complexed with mAb 64-3-7, demonstrates solvent exposure of these residues in the PR conformation. Docking and molecular dynamics predict how this segment moves to help form the A and B pockets crucial for the tight peptide binding needed for stability of the mature peptide-loaded conformation, chaperone dissociation, and Ag presentation.

Robinson H.; Mage, M.; Dolan, M.; Wang, R.; Boyd, L.; Revilleza, M.; Natarajan, K.; Myers, N.; Hansen, T.; Margulies, D.

2012-05-01T23:59:59.000Z

119

Non-Born-Oppenheimer path in anti-Hermitian dynamics for nonadiabatic transitions  

SciTech Connect

A serious difficulty in the semiclassical Ehrenfest theory for nonadiabatic transitions is that a path passing across the avoided crossing is forced to run on a potential averaged over comprising adiabatic potential surfaces that commit the avoided crossing. Therefore once a path passes through the crossing region, it immediately becomes incompatible with the standard view of 'classical trajectory' running on an adiabatic surface. This casts a fundamental question to the theoretical structure of chemical dynamics. In this paper, we propose a non-Born-Oppenheimer path that is generated by an anti-Hermitian Hamiltonian, whose complex-valued eigenenergies can cross in their real parts and avoid crossing in the imaginary parts in the vicinity of the nonadiabatic transition region. We discuss the properties of this non-Born-Oppenheimer path and thereby show its compatibility with the Born-Oppenheimer classical trajectories. This theory not only allows the geometrical branching of the paths but gives the nonadiabatic transition amplitudes and quantum phases along the generated paths.

Takatsuka, Kazuo [Department of Basic Science, The University of Tokyo, Komaba, 153-8902 Tokyo (Japan)

2006-02-14T23:59:59.000Z

120

Computational battery dynamics (CBD)--electrochemical/thermal coupled modeling and multi-scale modeling  

E-Print Network (OSTI)

Computational battery dynamics (CBD)--electrochemical/thermal coupled modeling and multi the development of first-principles based mathematical models for batteries developed on a framework parallel to computation fluid dynamics (CFD), herein termed computational battery dynamics (CBD). This general

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

A Game-Theoretical Dynamic Model for Electricity Markets  

E-Print Network (OSTI)

Oct 6, 2010 ... Abstract: We present a game-theoretical dynamic model for competitive electricity markets.We demonstrate that the model can be used to ...

Aswin Kannan

2010-10-06T23:59:59.000Z

122

Two-phase modeling of deflagration-to-detonation transition in granular materials: A critical examination of modeling issues  

E-Print Network (OSTI)

Two-phase modeling of deflagration-to-detonation transition in granular materials: A critical the deflagration-to-detonation transition DDT in granular explosives is critically reviewed. The continuum, analysis and numerical simulation of deflagration- to-detonation transition DDT in porous energetic

Kapila, Ashwani K.

123

Modeling and dynamic performance evaluation of target capture in robotic systems  

SciTech Connect

In this paper, a dynamic system consisting of a robot manipulator and a target is analyzed. The target is considered in a general way as a dynamic subsystem having finite mass and moments of inertia (e.g., a rigid body or a second robot). The situation investigated is when the robot establishes interaction with the target in such a way that it intercepts and captures a reference element of the target. The analysis of target capture is divided into three phases in terms of time: the precapture, free motion (finite motion); the transition from free to constrained motion in the vicinity of interception and capture (impulsive motion); and the postcapture, constrained motion (finite motion). The greatest attention is paid to the analysis of the phase of transition, the impulsive motion, and dynamics of the system. Based on the use of impulsive constraints and the Jourdainian formulation of analytical dynamics, a novel approach is proposed for the dynamic modeling of target capture by a robot manipulator. The proposed approach is suitable to handle both finite and impulsive motions in a common analytical framework. Based on the dynamic model developed and using a geometric representation of the system's dynamics, a detailed analysis and a performance evaluation framework are presented for the phase of transition. Both rigid and structurally flexible models of robots are considered. For the performance evaluation analyses, two main concepts are proposed and corresponding performance measures are derived. These tools may be used in the analysis, design, and control of time-varying robotic systems. The dynamic system of a three-link robot arm capturing a rigid body is used to illustrate the material presented.

Koevecses, J.; Cleghorn, W.L.; Fenton, R.G.

2000-04-01T23:59:59.000Z

124

MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL  

E-Print Network (OSTI)

MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL David G. Rossiter of Agronomy, Inc. #12;MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL Abstract Modeling inter-species competition is a natural application for dynamic simulation models

Rossiter, D G "David"

125

The quantum Biroli-Mézard model: glass transition and superfluidity in a quantum lattice glass model  

E-Print Network (OSTI)

We study the quantum version of a lattice model whose classical counterpart captures the physics of structural glasses. We discuss the role of quantum fluctuations in such systems and in particular their interplay with the amorphous order developed in the glass phase. We show that quantum fluctuations might facilitate the formation of the glass at low enough temperature. We also show that the glass transition becomes a first-order transition between a superfluid and an insulating glass at very low temperature, and is therefore accompanied by phase coexistence between superfluid and glassy regions.

Laura Foini; Guilhem Semerjian; Francesco Zamponi

2010-11-29T23:59:59.000Z

126

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

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tar sands/ extra-heavy oil and shale have zero Resource-D. J. and Cecchine, G. Oil shale development in the Unitedresources of some world oil-shale deposits. Technical Report

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

127

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

128

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

129

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

130

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

131

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

E-Print Network (OSTI)

and income on energy and oil demand. Energy Journal, 23(1):scenario, with demand and conventional oil endowment set toPrice elasticity of demand for crude oil: estimates for 23

Brandt, Adam R.; Farrell, Alexander E.

2008-01-01T23:59:59.000Z

132

The Ising Model on a Dynamically Triangulated Disk with a Boundary Magnetic Field  

E-Print Network (OSTI)

We use Monte Carlo simulations to study a dynamically triangulated disk with Ising spins on the vertices and a boundary magnetic field. For the case of zero magnetic field we show that the model possesses three phases. For one of these the boundary length grows linearly with disk area, while the other two phases are characterized by a boundary whose size is on the order of the cut-off. A line of continuous magnetic transitions separates the two small boundary phases. We determine the critical exponents of the continuous magnetic phase transition and relate them to predictions from continuum 2-d quantum gravity. This line of continuous transitions appears to terminate on a line of discontinuous phase transitions dividing the small boundary phases from the large boundary phase. We examine the scaling of bulk magnetization and boundary magnetization as a function of boundary magnetic field in the vicinity of this tricritical point.

Scott McGuire; Simon Catterall; Mark Bowick; Simeon Warner

2001-05-02T23:59:59.000Z

133

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

134

Insulator/Chern-insulator transition in the Haldane model T. Thonhauser and David Vanderbilt  

E-Print Network (OSTI)

Insulator/Chern-insulator transition in the Haldane model T. Thonhauser and David Vanderbilt properties of the Haldane model as the system undergoes its transition from the normal-insulator to the Chern-insulator phase. We find that the density matrix has expo- nential decay in both insulating phases, while having

Vanderbilt, David

135

A Dynamical IS-LM Model Allen Tang  

E-Print Network (OSTI)

A Dynamical IS-LM Model Allen Tang The University of North Carolina the specifications of a discrete dynamical IS-LM model and discuss how this model can of monetary policy, to an economy. The standard static IS-LM model arises

Marzuola, Jeremy

136

Hydrodynamic modeling of deconfinement phase transition in heavy-ion collisions at NICA-FAIR energies  

E-Print Network (OSTI)

We use (3+1) dimensional ideal hydrodynamics to describe the space-time evolution of strongly interacting matter created in Au+Au and Pb+Pb collisions. The model is applied for the domain of bombarding energies 1-160 AGeV which includes future NICA and FAIR experiments. Two equations of state are used: the first one corresponding to resonance hadron gas and the second one including the deconfinement phase transition. The initial state is represented by two Lorentz-boosted nuclei. Dynamical trajectories of matter in the central box of the system are analyzed. They can be well represented by a fast shock-wave compression followed by a relatively slow isentropic expansion. The parameters of collective flows and hadronic spectra are calculated under assumption of the isochronous freeze-out. It is shown that the deconfinement phase transition leads to broadening of proton rapidity distributions, increase of elliptic flows and formation of the directed antiflow in the central rapidity region. These effects are most pronounced at bombarding energies around 10 AGeV, when the system spends the longest time in the mixed phase. From the comparison with three-fluid calculations we conclude that the transparency effects are not so important in central collisions at NICA-FAIR energies (below 30 AGeV).

A. V. Merdeev; L. M. Satarov; I. N. Mishustin

2011-03-21T23:59:59.000Z

137

Observations of a dynamical-to-kinematic diffraction transition in plastically deformed polycrystalline intermetallic YCu  

SciTech Connect

Unlike most intermetallic compounds, polycrystalline YCu, a B2 (CsCl-type) intermetallic, is ductile at room temperature. The mechanisms for this behavior are not fully understood. In situ neutron diffraction was used to investigate whether a stress-induced phase transformation or twinning contribute to the ductility; however, neither mechanism was found to be active in YCu. Surprisingly, this study revealed that the intensities of the diffraction peaks increased after plastic deformation. It is thought that annealing the samples created nearly perfect crystallinity, and subsequent deformation reduced this high degree of lattice coherency, resulting in a modified mosaic structure that decreased or eliminated the extinction effect. Analysis of changes in diffraction peak intensity showed a region of primary plasticity that exhibits significant changes in diffraction behavior. Fully annealed samples initially contain diffracting volumes large enough to follow the dynamical theory of diffraction. When loaded beyond the yield point, dislocation motion disrupts the lattice perfection, and the diffracting volume is reduced to the point that diffraction follows the kinematic theory of diffraction. Since the sample preparation and deformation mechanisms present in this study are common in numerous material systems, this dynamical to kinematic diffraction transition should also be considered in other diffraction experiments. These measurements also suggest the possibility of a new method of investigating structural characteristics. (C) 2014 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

Williams, Scott H. [Ames Laboratory; Brown, Donald W. [Los Alamos National Laboratory; Clausen, Bjorn [Los Alamos National Laboratory; Russell, Alan [Ames Laboratory; Gschneidner Jr., Karl A. [Ames Laboratory

2014-03-01T23:59:59.000Z

138

Effects of inhomogeneous influence of individuals on an order-disorder transition in opinion dynamics  

Science Journals Connector (OSTI)

We study the effects of inhomogeneous influence of individuals on collective phenomena. We focus analytically on a typical model of the majority rule, applied to the completely connected agents. Two types of individuals A and B with different influence activity are introduced. The individuals A and B are distributed randomly with concentrations ? and 1?? at the beginning and fixed further on. Our main result is that the location of the order-disorder transition is affected due to the introduction of the inhomogeneous influence. This result highlights the importance of inhomogeneous influence between different types of individuals during the process of opinion updating.

Jian-Yue Guan; Zhi-Xi Wu; Ying-Hai Wang

2007-10-11T23:59:59.000Z

139

Censored Glauber Dynamics for the Mean Field Ising Model  

E-Print Network (OSTI)

dynamics for the Mean-?eld Ising Model: cut-off, criticaldynamics for the mean-?eld Ising model. Commun. Math. Phys.to equilibrium of stochastic Ising models in the Dobrushin

Ding, Jian; Lubetzky, Eyal; Peres, Yuval

2009-01-01T23:59:59.000Z

140

Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction  

E-Print Network (OSTI)

. Current weather radar detection and prediction sys- tems primarily rely on numerical models. We proposeOpen problem: Dynamic Relational Models for Improved Hazardous Weather Prediction Amy McGovern1, #12;Dynamic Relational Models for Improved Hazardous Weather Prediction Radar velocity Radar

McGovern, Amy

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

HOMOGENEOUS MODELS IN GENERAL RELATIVITY AND GAS DYNAMICS  

E-Print Network (OSTI)

HOMOGENEOUS MODELS IN GENERAL RELATIVITY AND GAS DYNAMICS O. I. BOGOYAVLENSKII AND S. P. NOVIKOV analytically) in general relativity and gas dynamics. The investigation of these models is carried out begins with a short survey of results on non-trivial models (that is, those that are not integrable

Novikov, Sergei Petrovich

142

Temperature dependent photoexcited carrier dynamics in multiferroic BiFeO{sub 3} film: A hidden phase transition  

SciTech Connect

The ultrafast carrier dynamics of the multiferroic BiFeO{sub 3} film in a broad temperature range is investigated using optical pump-probe spectroscopy. The photoexcited electrons release their energy with optical phonons emission through electron-phonon coupling in about 1 ps. The following intermediate process is identified as dynamical spin-lattice coupling in several picoseconds. Furthermore, the peak values of the optical reflectivity and the time constants of carrier relaxation channels show significant changes while the temperature varies from 137.5?K to around 195?K, this aligns with the previously reported hidden phase transition. Our study demonstrates that ultrafast spectroscopy is a sensitive method to look into the dynamical interactions among the on-site high-energy electrons accumulated in the p conduction band of Bi, coherent optical phonon, as well as the spin degree of freedom. These features play crucial roles in the characterization of phase transitions.

Zhang, Zeyu; Jin, Zuanming; Pan, Qunfeng; Xu, Yue; Lin, Xian; Ma, Guohong, E-mail: ghma@staff.shu.edu.cn, E-mail: cheng@uow.edu.au [Department of Physics, Shanghai University, Shanghai 200444 (China); Cheng, Zhenxiang, E-mail: ghma@staff.shu.edu.cn, E-mail: cheng@uow.edu.au [Department of Physics, Shanghai University, Shanghai 200444 (China); Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2500 (Australia)

2014-04-14T23:59:59.000Z

143

Smoothing in dynamic generalized linear models by Gibbs sampling  

Science Journals Connector (OSTI)

Optimal filtering and smoothing in non-Gaussian dynamic models based on ... approach for obtaining posterior mean smoothers in the exponential family framework. Implementation and performance are investigated...

Ludwig Fahrmeir; Wolfgang Hennevogl…

1992-01-01T23:59:59.000Z

144

2 × 2 commensurate-incommensurate transition in Ising models: Monte Carlo simulation  

Science Journals Connector (OSTI)

Phase diagrams of Ising models with antiferromagnetic nearest-(NN) and next-nearest-neighbor (NNN) interactions are obtained by Monte Carlo simulations. For the triangular lattice a paramagnetic (P)-2×2 commensurate (C) phase transition is found, which is second order when the NN interaction is small. The exponents are consistent with the ones of the four-state Potts model. For large NNN interactions the transition becomes first order. For three-dimensional stacking of triangular layers an incommensurate (I) phase is found in addition. The P-C and I-C transitions are of first order whereas the P-I transition seems to be of second order. The model is used to interpret the P-I-C transitions in ?-eucryptite.

Y. Saito

1981-12-01T23:59:59.000Z

145

Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile  

E-Print Network (OSTI)

Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile Robot. It actively balances and moves on a single wheel using closed loop feedback, making it dynamically stable it a good candidate for operating in human environments. Balancing on a ball allows Ballbot to be omni

146

A dynamic model for the Lagrangian stochastic dispersion coefficient  

SciTech Connect

A stochastic sub-grid model is often used to accurately represent particle dispersion in turbulent flows using large eddy simulations. Models of this type have a free parameter, the dispersion coefficient, which is not universal and is strongly grid-dependent. In the present paper, a dynamic model for the evaluation of the coefficient is proposed and validated in decaying homogeneous isotropic turbulence. The grid dependence of the static coefficient is investigated in a turbulent mixing layer and compared to the dynamic model. The dynamic model accurately predicts dispersion statistics and resolves the grid-dependence. Dispersion statistics of the dynamically calculated constant are more accurate than any static coefficient choice for a number of grid spacings. Furthermore, the dynamic model produces less numerical artefacts than a static model and exhibits smaller sensitivity in the results predicted for different particle relaxation times.

Pesmazoglou, I.; Navarro-Martinez, S., E-mail: s.navarro@imperial.ac.uk [Department of Mechanical Engineering, Imperial College, London SW7 2AZ (United Kingdom); Kempf, A. M. [Chair of Fluid Dynamics, Institute for Combustion and Gasdynamics and Center for Computational Sciences and Simulation, Universität Duisburg-Essen, Duisburg, 47048 (Germany)] [Chair of Fluid Dynamics, Institute for Combustion and Gasdynamics and Center for Computational Sciences and Simulation, Universität Duisburg-Essen, Duisburg, 47048 (Germany)

2013-12-15T23:59:59.000Z

147

Event-Based Approach to Modelling Dynamic Architecture  

E-Print Network (OSTI)

Event-Based Approach to Modelling Dynamic Architecture: Application to Mobile Ad-Hoc Network.Attiogbe@univ-nantes.fr Abstract. We describe an event-based approach to specifiy systems with dynamically evolving architecture tools. Keywords: Specification, Verification, Dynamic Architecture, Event B. 1 Introduction Distributed

Paris-Sud XI, Université de

148

Dynamic Modeling of a Two Wheeled Vehicle : Jourdain Formalism  

E-Print Network (OSTI)

This paper presents a motorcycle direct dynamic formulation by the Jourdain's principle approach on the motorcycle's handlebar. Simulation results reveal some dynamics features like load transfer and counter-steering phenomena. keywords Motorcycle modeling, motorcycle control, Jourdain's dynamics principle. 1 Introduction

Paris-Sud XI, Université de

149

Modelling and Verification of Automated Transit Systems, Using Timed Automata, Invariants and  

E-Print Network (OSTI)

Modelling and Verification of Automated Transit Systems, Using Timed Automata, Invariants in automated transit systems. The problems we consider are in- spired by design work in the Personal Rapid and Simulations Nancy Lynch * Laboratory for Computer Science, Massachusetts Institute of Technology, Cambridge

Lynch, Nancy

150

Modelling and Veri cation of Automated Transit Systems, using Timed Automata, Invariants and  

E-Print Network (OSTI)

Modelling and Veri cation of Automated Transit Systems, using Timed Automata, Invariants in automated transit systems. The problems we consider are in- spired by design work in the Personal Rapid and Simulations Nancy Lynch ? Laboratory for Computer Science, Massachusetts Institute of Technology, Cambridge

Lynch, Nancy

151

Electroweak phase transition in the economical 3-3-1 model  

E-Print Network (OSTI)

Following our approach to the electroweak phase transition (EWPT), we consider the phase transitions in framework of the economical 3-3-1 model (E331). Structure of phase transition in this model is divided into two periods. The first period is the phase transition $SU(3) \\rightarrow SU(2)$ at TeV scale and the second one is $SU(2) \\rightarrow U(1)$, which is like the Standard Model (SM) electroweak phase transition. Two periods are the first-order phase transitions if the masses of heavy bosons is equal to few TeVs and the mass of second neutral Higgs is, $0transition period is $1<\\omega<5$ TeV. In addition, we also derived conditions of the self interaction parameters in the Higgs potential. Therefore, new bosons are the triggers of the first-order electroweak phase transition with significant implications for the viability of electroweak baryogenesis scenarios in this model.

Phong, Vo Quoc; Van, Vo Thanh; Minh, Le Hoang

2014-01-01T23:59:59.000Z

152

Simulating and Visualising Phase Transitions: Small-World Effects on the Monte Carlo Ising Model  

E-Print Network (OSTI)

Simulating and Visualising Phase Transitions: Small-World Effects on the Monte Carlo Ising Model K Science, Institute of Information & Mathematical Sciences, Massey University, Albany The Ising Model Many temperature and the material becomes magnetic. A simulation model such as the Ising model has been widely used

Hawick, Ken

153

Developing decision support tools for rangeland management by combining state and transition models and Bayesian belief networks  

E-Print Network (OSTI)

Developing decision support tools for rangeland management by combining state and transition models 2008 Keywords: Rangeland management State and transition model Queensland Bayesian belief network Adaptive management Decision support a b s t r a c t State and transition models provide a simple

154

Molecular dynamics simulation of phosphorylation-induced conformational transitions in the mycobacterium tuberculosis response regulator PrrA  

SciTech Connect

Phosphorylation-activated modulation of response regulators (RR) is predominantly used by bacteria as a strategy in regulating their two-component signaling (TCS) systems, the underlying molecular mechanisms are however far from fully understood. In this work we have conducted a molecular dynamics (MD) simulation of the phosphorylation-induced conformational transitions of RRs with the Mycobacterium Tuberculosis PrrA as a particular example. Starting from the full-length inactive structure of PrrA we introduced a local disturbance by phosphorylating the conserved aspartic acid residue, Asp-58, in the regulatory domain. A Go-model-type algorithm packaged with AMBER force fields was then applied to simulate the dynamics upon phosphorylation. The MD simulation shows that the phosphorylation of Asp-58 facilitates PrrA, whose inactive state has a compact conformation with a closed interdomain interface, to open up with its interdomain separation being increased by an average of about 1.5 {angstrom} for a simulation of 20 ns. The trans-activation loop, which is completely buried within the interdomain interface in the inactive PrrA, is found to become more exposed with the phosphorylated structure as well. These results provide more structural details of how the phosphorylation of a local aspartate activates PrrA to undergo a global conformational rearrangement toward its extended active state. This work also indicates that MD simulations can serve as a fast tool to unravel the regulation mechanisms of all RRs, which is especially valuable when the structures of full-length active RRs are currently unavailable.

Chen, Guo [Los Alamos National Laboratory; Mcmahon, Benjamin H [Los Alamos National Laboratory; Tung, Chang - Shung [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

155

A dynamic term structure model of Central Bank policy  

E-Print Network (OSTI)

This thesis investigates the implications of explicitly modeling the monetary policy of the Central Bank within a Dynamic Term Structure Model (DTSM). We follow Piazzesi (2005) and implement monetary policy by including ...

Staker, Shawn W

2009-01-01T23:59:59.000Z

156

Numerical Analyses of CERN 200 GeV/A Heavy-Ion Collisions Based on a Hydrodynamical Model with Phase Transition  

Science Journals Connector (OSTI)

......A Heavy-Ion Collisions...Model with Phase Transition Shin Muroya...A Heavy-Ion Collisions...Model with Phase Transition Shin MUROYA...model with phase- transition to the recent heavy-ion experiments......

Shin Muroya; Hiroki Nakamura; Mikio Namiki

1995-03-01T23:59:59.000Z

157

On the roughening transition in the Potts model (q=2, 3) in two and three dimensions  

Science Journals Connector (OSTI)

Roughening-respectively depinning-transitions of interfaces between regions...q-state Potts model (q=2, 3) in two and three dimensions. For two dimensions the depinning temperatureT ...

I. Schmidt; W. Pesch

1984-01-01T23:59:59.000Z

158

Deep Convective Transition Characteristics in the Community Climate System Model and Changes under Global Warming  

Science Journals Connector (OSTI)

Tropical deep convective transition characteristics, including precipitation pickup, occurrence probability, and distribution tails related to extreme events, are analyzed using uncoupled and coupled versions of the Community Climate System Model (...

Sandeep Sahany; J. David Neelin; Katrina Hales; Richard B. Neale

2014-12-01T23:59:59.000Z

159

PHYSICAL REVIEW E 84, 041602 (2011) Predrying transition on a hydrophobic surface: Statics and dynamics  

E-Print Network (OSTI)

on the coexistence curve. Furthermore, there is a phase transition of adsorption between a thin and thick liquid. In this paper, we examine a predrying phase transition between a thin and thick low-density layer, ions, and hydrophobic particles should greatly affect the transition [27]. As in the prewetting case

160

Fragment production in central heavy-ion collisions: reconciling the dominance of dynamics with observed phase transition signals through universal fluctuations  

E-Print Network (OSTI)

Fragment production in central collisions of Xe+Sn has been systematically studied with the INDRA multidetector from 25 to 150 AMeV. The predominant role of collision dynamics is evidenced in multiple intermediate mass fragment production even at the lowest energies, around the so-called "multifragmentation threshold". For beam energies 50 AMeV and above, a promising agreement with suitably modified Antisymmetrised Molecular Dynamics calculations has been achieved. Intriguingly the same reactions have recently been interpreted as evidence for a liquid-gas phase transition in thermodynamically equilibrated systems. The universal fluctuation theory, thanks to its lack of any equilibrium hypothesis, shows clearly that in all but a tiny minority of carefully-selected central collisions fragment production is incompatible with either critical or phase coexistence behaviour. On the other hand, it does not exclude some similarity with aggregation scenarios such as the lattice-gas or Fisher droplet models.

J. D. Frankland; A. Chbihi; S. Hudan; A. Mignon; A. Ono; for the INDRA; ALADIN collaborations

2002-02-28T23:59:59.000Z

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

Workforce Transition Model for DOE-AL non-nuclear reconfiguration  

SciTech Connect

The Pacific Northwest Laboratory (PNL) was tasked by the US Department of Energy Albuquerque Field Office (DOE-AL) to develop a workforce assessment and transition planning tool to support integrated decision making at a single DOE installation. The planning tool permits coordinated, integrated workforce planning to manage growth, decline, or transition within a DOE installation. The tool enhances the links and provides commonality between strategic, programmatic, and operations planners and human resources. Successful development and subsequent complex-wide implementation of the model will also facilitate planning at the national level by enforcing a consistent format on data that are now collected by installations in corporate-specific formats that are not amenable to national-level analyses. The workforce assessment and transition planning tool consists of two components: the Workforce Transition Model and the Workforce Budget Constraint Model. The Workforce Transition Model, the preponderant of the two, assists decision makers to identify and evaluates alternatives for transitioning the current workforce to meet the skills required to support projected workforce requirements. The Workforce Budget Constraint Model helps estimate the number of personnel that will be affected given a workforce budget increase or decrease and assists in identifying how the corresponding hiring or layoffs should be distributed across the common occupational classification system (COCS) occupations. The conceptual models and the computer implementation are described.

Stahlman, E.J.; Lewis, R.E.

1993-10-01T23:59:59.000Z

162

Single tensionless transition in the Laplacian roughening model Juan Jess Ruiz-Lorenzo,1  

E-Print Network (OSTI)

Single tensionless transition in the Laplacian roughening model Juan Jesús Ruiz-Lorenzo,1 Esteban Laplacian roughening dLr model, originally introduced as the simplest one accommodating the hexatic phase in two-dimensional melting. The dLr model is also relevant to surface roughening in molecular beam

Cuerno, Rodolfo

163

A computational fluid dynamics model for wind simulation: model implementation and experimental validation  

Science Journals Connector (OSTI)

To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed ... analysis and modelling tool (...

Zhuo-dong Zhang; Ralf Wieland; Matthias Reiche…

2012-04-01T23:59:59.000Z

164

Assessment of One- and Two-Equation Turbulence Models for Hypersonic Transitional Flows  

SciTech Connect

Many Navier-Stokes codes require that the governing equations be written in conservation form with a source term. The Spalart-Allmaras one-equation model was originally developed in substantial derivative form and when rewritten in conservation form, a density gradient term appears in the source term. This density gradient term causes numerical problems and has a small influence on the numerical predictions. Further work has been performed to understand and to justify the neglect of this term. The transition trip term has been included in the one-equation eddy viscosity model of Spalart-Allmaras. Several problems with this model have been discovered when applied to high-speed flows. For the Mach 8 flat plate boundary layer flow with the standard transition method, the Baldwin-Barth and both k-{omega} models gave transition at the specified location. The Spalart-Allmaras and low Reynolds number k-{var_epsilon} models required an increase in the freestream turbulence levels in order to give transition at the desired location. All models predicted the correct skin friction levels in both the laminar and turbulent flow regions. For Mach 8 flat plate case, the transition location could not be controlled with the trip terms as given in the Spalart-Allmaras model. Several other approaches have been investigated to allow the specification of the transition location. The approach that appears most appropriate is to vary the coefficient that multiplies the turbulent production term in the governing partial differential equation for the eddy viscosity (Method 2). When this coefficient is zero, the flow remains laminar. The coefficient is increased to its normal value over a specified distance to crudely model the transition region and obtain fully turbulent flow. While this approach provides a reasonable interim solution, a separate effort should be initiated to address the proper transition procedure associated with the turbulent production term. Also, the transition process might be better modeled with the Spalart-Allmaras turbulence model with modification of the damping function f{sub v1}. The damping function could be set to zero in the laminar flow region and then turned on through the transition flow region.

ROY,CHRISTOPHER J.; BLOTTNER,FREDERICK G.

2000-01-14T23:59:59.000Z

165

Bifurcation theory of a one-dimensional transport model for the L-H transition  

SciTech Connect

Transitions between low and high-confinement (L-H transitions) in magnetically confined plasmas can appear as three qualitatively different types: sharp, smooth, and oscillatory. Bifurcation analysis unravels these possible transition types and how they are situated in parameter space. In this paper the bifurcation analysis is applied to a 1-dimensional model for the radial transport of energy and density near the edge of magnetically confined plasmas. This phenomenological L-H transition model describes the reduction of the turbulent transport by E×B-flow shear self-consistently with the evolution of the radial electric field. Therewith, the exact parameter space, including the threshold values of the control parameters, of the possible L-H transitions in the model is determined. Furthermore, a generalised equal area rule is derived to describe the evolution of the transport barrier in space and time self-consistently. Applying this newly developed rule to the model analysed in this paper reveals a naturally occurring transition to an extra wide transport barrier that may correspond to the improved confinement known as the very-high-confinement mode.

Weymiens, W.; Blank, H. J. de; Hogeweij, G. M. D. [FOM Institute DIFFER—Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, Nieuwegein (Netherlands)] [FOM Institute DIFFER—Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, PO Box 1207, Nieuwegein (Netherlands)

2013-08-15T23:59:59.000Z

166

Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model  

E-Print Network (OSTI)

Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model Yi Transport of suspended sediment in high Reynolds number channel flows Re=O 600 000 is simulated using large-eddy simulation along with a dynamic-mixed model DMM . Because the modeled sediment concentration is low

Fringer, Oliver B.

167

Subcycled dynamics in the Spectral Community Atmosphere Model, version 4  

SciTech Connect

To gain computational efficiency, a split explicit time integration scheme has been implemented in the CAM spectral Eulerian dynamical core. In this scheme, already present in other dynamical core options within the Community Atmosphere Model, version 4 (CAM), the fluid dynamics portion of the model is subcycled to allow a longer time step for the parameterization schemes. The physics parameterization of CAM is not subject to the stability restrictions of the fluid dynamics, and thus finer spatial resolutions of the model do not require the physics time step to be reduced. A brief outline of the subcycling algorithm implementation and resulting model efficiency improvement is presented. A discussion regarding the effect of the climate statistics derived from short model runs is provided.

Taylor, Mark [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Evans, Katherine J [ORNL] [ORNL; Hack, James J [ORNL] [ORNL; Worley, Patrick H [ORNL] [ORNL

2010-01-01T23:59:59.000Z

168

The Mixing Time Evolution of Glauber Dynamics for the Mean-Field Ising Model  

E-Print Network (OSTI)

dynamics for the mean-?eld Ising model. http://arxiv. org/dynamics for the mean-?eld Ising model: cut-off, criticalDynamics for the Mean-Field Ising Model Jian Ding 1, , Eyal

Ding, Jian; Lubetzky, Eyal; Peres, Yuval

2009-01-01T23:59:59.000Z

169

Fibre Based Modeling of Wood Dynamics and Fracture  

E-Print Network (OSTI)

Fibre Based Modeling of Wood Dynamics and Fracture by Sean Meiji Sutherland B.Sc., The University for the simulation of the dynamics and fracturing char- acteristics of wood, specifically its anisotropic behaviour bundles of fibres. Additionally, we describe the conditions under which fracture occurs in the material

Bridson, Robert

170

Dynamic Modelling for Control of Fuel Cells Federico Zenith  

E-Print Network (OSTI)

Dynamic Modelling for Control of Fuel Cells Federico Zenith Sigurd Skogestad Department of Chemical Engineering Norwegian University of Science and Technology ( ntnu) Trondheim Abstract Fuel-cell dynamics have been investigated with a variable-resistance board applied to a high temperature polymer fuel cell

Skogestad, Sigurd

171

A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling  

E-Print Network (OSTI)

A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling and Control L. Nehaoua of these techniques to other simulators (cars and motorcycles) is possible but not direct. Indeed, the dynamics motorcycle driving simulators were build. The first prototype was developed by Honda in 1988

Paris-Sud XI, Université de

172

THE ISING MODEL: PHASE TRANSITION IN A SQUARE ALEXANDRE R. PUTTICK  

E-Print Network (OSTI)

THE ISING MODEL: PHASE TRANSITION IN A SQUARE LATTICE ALEXANDRE R. PUTTICK Abstract. The aim of this paper is to give a mathematical treatment of the Ising model, named after its orginal contributor Ernst Ising (1925). The paper will present a brief history concerning the early formulation and applications

May, J. Peter

173

Spin-One Ising Model for Ice VII–Plastic Ice Phase Transitions  

Science Journals Connector (OSTI)

We propose a spin model compatible with ice VII–plastic ice phase transitions and critical phenomena discovered recently by computer simulations. The Blume–Capel spin-1 Ising model is extended in order to describe the entropic stabilization effect in the ...

Masakazu Matsumoto; Kazuhiro Himoto; Hideki Tanaka

2014-08-21T23:59:59.000Z

174

Dynamic energy budget approaches for modelling organismal ageing  

Science Journals Connector (OSTI)

...quantitative approach. New York, NY: Harwood Academic...1928 The rate of living. New York, NY: Knopf. Ricklefs...A. L. M. 2010 Dynamic energy budget theory restores coherence...Nothobranchius furzeri as a new model system for aging studies...

2010-01-01T23:59:59.000Z

175

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

176

Dynamics of Ising models with damping J. M. Deutsch  

E-Print Network (OSTI)

Dynamics of Ising models with damping J. M. Deutsch Department of Physics, University of California Donostia, Spain Received 30 August 2007; published 28 March 2008 We show for the Ising model, both from a theoretical standpoint and for numerical efficiency. Ising models are perhaps the best

Deutsch, Josh

177

Global registration of dynamic range scans for articulated model reconstruction  

Science Journals Connector (OSTI)

We present the articulated global registration algorithm to reconstruct articulated 3D models from dynamic range scan sequences. This new algorithm aligns multiple range scans simultaneously to reconstruct a full 3D model from the geometry of these scans. ... Keywords: Range scanning, animation reconstruction, articulated model, nonrigid registration

Will Chang; Matthias Zwicker

2011-05-01T23:59:59.000Z

178

Cognitive Modeling Carsten Pfeffer Dynamical Systems Approaches to  

E-Print Network (OSTI)

Cognitive Modeling Carsten Pfeffer Dynamical Systems Approaches to Cognition Carsten Pfeffer Universität Bremen December 1st, 2014 December 1st, 2014 1/30 #12;Cognitive Modeling Carsten Pfeffer Introduction Physical Symbol Systems December 1st, 2014 2/30 #12;Cognitive Modeling Carsten Pfeffer

Bremen, Universität

179

COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS  

E-Print Network (OSTI)

COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS Ugur Pasaogullari and Chao-dimensional model has been developed to simulate solid oxide fuel cells (SOFC). The model fully couples current density operation. INTRODUCTION Solid oxide fuel cells (SOFC) are among possible candidates

180

New model describing the dynamical behaviour of penetration rates  

Science Journals Connector (OSTI)

We propose a hierarchical logistic equation as a model to describe the dynamical behaviour of a penetration rate of a prevalent stuff. In this model, a memory, how many people who already possess it a person who does not process it yet met, is considered, which does not exist in the logistic model. As an application, we apply this model to iPod sales data, and find that this model can approximate the data much better than the logistic equation.

Tohru Tashiro; Hiroe Minagawa; Michiko Chiba

2013-01-01T23:59:59.000Z

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.


181

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

182

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

2013-12-01T23:59:59.000Z

183

Extra entropy production due to nonequilibrium phase transitions in relativistic heavy ion reactions  

Science Journals Connector (OSTI)

In a fluid-dynamical model, the extra entropy production which arises from a nonequilibrium phase transition from nuclear to quark-gluon matter is calculated.

H. W. Barz; B. Kämpfer; B. Lukács; L. P. Csernai

1985-01-01T23:59:59.000Z

184

Dynamic Analysis and Modeling of Jansen Mechanism  

Science Journals Connector (OSTI)

Abstract Theo Jansen mechanism is gaining wide spread popularity among legged robotics researchers due to its scalable design, energy efficiency, low payload to machine load ratio, bio-inspired locomotion, deterministic foot trajectory among others. In this paper, we present dynamic analysis of a four legged Theo Jansen link mechanism using projection method that results in constraint force and equivalent Lagrange's equation of motion necessary for any meaningful extension and/or optimization of this niche mechanism. Numerical simulations using MaTX is presented in conjunction with the dynamic analysis. This research sets a theoretical basis for future investigation into Theo Jansen mechanism.

Shunsuke Nansai; Mohan Rajesh Elara; Masami Iwase

2013-01-01T23:59:59.000Z

185

Mathematical Models of Solid-Solid Phase Transitions in Steel  

Science Journals Connector (OSTI)

......1803-1815. HAYES, W. J. 1985 Mathematical models in materials science. M.Sc. Thesis, Oxford. SCHEIL, E. 1935 Anlaufzeit den Austenitumwandlung. Archiv fUr Eisenhuttenwesen 8, 565. VERDI, C , & VISINTIN, A. 1987a Numerical analysis of the......

A. VISINTIN

1987-01-01T23:59:59.000Z

186

Transition Prediction for Scramjet Intakes Using the \\gamma-Re_\\theta_t Model Coupled to Two Turbulence Models  

E-Print Network (OSTI)

Due to the thick boundary layers in hypersonic flows, the state of the boundary layer significantly influences the whole flow field as well as surface heat loads. Hence, for engineering applications the efficient numerical prediction of laminar-to-turbulent transition is a challenging and important task. Within the framework of the Reynolds averaged Navier-Stokes equations, Langtry/Menter [1] proposed the -Re?t transition model using two transport equations for the intermittency and Re?t combined with the Shear Stress Transport turbulence model (SST) [2]. The transition model contains two empirical correlations for onset and length of transition. Langtry/Menter [1] designed and validated the correlations for the subsonic and transonic flow regime. For our applications in the hypersonic flow regime, the development of a new set of correlations proved necessary, even when using the same SST turbulence model [3]. Within this paper, we propose a next step and couple the transition model with the SSG/LRR-! Reynold...

Frauholz, Sarah; Müller, Siegfried; Behr, Marek

2014-01-01T23:59:59.000Z

187

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

188

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

189

Short-time dynamics of Fe{sub 2}/V{sub 13} magnetic superlattice models  

SciTech Connect

Critical relaxation from a low-temperature fully ordered state of Fe{sub 2}/V{sub 13} iron-vanadium magnetic superlattice models has been studied using the method of short-time dynamics. Systems with three variants of the ratio R of inter-to intralayer exchange coupling have been considered. Particles with N = 262144 spins have been simulated with periodic boundary conditions. Calculations have been performed using the standard Metropolis algorithm of the Monte Carlo method. The static critical exponents of magnetization and correlation radius, as well as the dynamic critical exponent, have been calculated for three R values. It is established that a small decrease in the exchange ratio (from R = 1.0 to 0.8) does not significantly influence the character of the short-time dynamics in the models studied. A further significant decrease in this ratio (to R = 0.01), for which a transition from three-dimensional to quasi-two-dimensional magnetism is possible, leads to significant changes in the dynamic behavior of iron-vanadium magnetic superlattice models.

Murtazaev, A. K.; Mutailamov, V. A., E-mail: vadim.mut@mail.ru [Russian Academy of Sciences, Amirkhanov Institute of Physics, Daghestan Scientific Center (Russian Federation)

2013-04-15T23:59:59.000Z

190

Modelling the balanced transition to a sustainable economy  

E-Print Network (OSTI)

carbon and low capital intensive activities and a combined green-low growth option that focuses. We consider a world economy with two subregions that are endowed with greenhouse gas emissions of atmospheric carbon dioxide (CO2) which is the major contributor to greenhouse gas emissions. The model

Nesterov, Yurii

191

Mean First-Passage Time Calculations for the Coil-to-Helix Transition:? The Active Helix Ising Model  

Science Journals Connector (OSTI)

Mean First-Passage Time Calculations for the Coil-to-Helix Transition:? The Active Helix Ising Model† ... The kinetics and thermodynamics of the coil-to-helix transition is studied using a one-dimensional “Zimm?Bragg” Ising model. ... 4. Mean First-Passage Time for the Active-Helix Ising Model ...

Nicolae-Viorel Buchete; John E. Straub

2001-06-20T23:59:59.000Z

192

Mean First-Passage Time Calculations for the Coil-to-Helix Transition: The Active Helix Ising Model  

E-Print Network (OSTI)

Mean First-Passage Time Calculations for the Coil-to-Helix Transition: The Active Helix Ising Model of the coil-to-helix transition is studied using a one-dimensional "Zimm- Bragg" Ising model. The mean first-dimensional Ising model for arbitrary spin-spin coupling (J) and external field (H) where J and H are expressed

Straub, John E.

193

Structure formation: Models, Dynamics and Status  

E-Print Network (OSTI)

The constraints on the models for the structure formation arising from various cosmological observations at different length scales are reviewed. The status of different models for structure formation is examined critically in the light of these observations.

T. Padmanabhan

1995-08-25T23:59:59.000Z

194

More dynamical models of our Galaxy  

Science Journals Connector (OSTI)

......rapidly at z 1kpc. In general sigma mirrors v , rising as v falls. The bottom-left...data have been interpreted with either Schwarzschild models (Cappellari et al. ) or models...with greater ease than is possible with Schwarzschild models and greater rigour than the Jeans......

James Binney

2012-10-21T23:59:59.000Z

195

Vacancy diffusion in colloidal crystals as determined by dynamical density-functional theory and the phase-field-crystal model  

E-Print Network (OSTI)

A two-dimensional crystal of repulsive dipolar particles is studied in the vicinity of its melting transition by using Brownian dynamics computer simulation, dynamical density functional theory and phase-field crystal modelling. A vacancy is created by taking out a particle from an equilibrated crystal and the relaxation dynamics of the vacancy is followed by monitoring the time-dependent one-particle density. We find that the vacancy is quickly filled up by diffusive hopping of neighbouring particles towards the vacancy center. We examine the temperature dependence of the diffusion constant and find that it decreases with decreasing temperature in the simulations. This trend is reproduced by the dynamical density functional theory. Conversely, the phase field crystal calculations predict the opposite trend. Therefore, the phase-field model needs a temperature-dependent expression for the mobility to predict trends correctly.

Sven van Teeffelen; Cristian Vasile Achim; Hartmut Löwen

2013-02-05T23:59:59.000Z

196

An infinite-period phase transition versus nucleation in a stochastic model of collective oscillations  

E-Print Network (OSTI)

A lattice model of three-state stochastic phase-coupled oscillators has been shown by Wood et al (2006 Phys. Rev. Lett. 96 145701) to exhibit a phase transition at a critical value of the coupling parameter, leading to stable global oscillations. We show that, in the complete graph version of the model, upon further increase in the coupling, the average frequency of collective oscillations decreases until an infinite-period (IP) phase transition occurs, at which point collective oscillations cease. Above this second critical point, a macroscopic fraction of the oscillators spend most of the time in one of the three states, yielding a prototypical nonequilibrium example (without an equilibrium counterpart) in which discrete rotational (C_3) symmetry is spontaneously broken, in the absence of any absorbing state. Simulation results and nucleation arguments strongly suggest that the IP phase transition does not occur on finite-dimensional lattices with short-range interactions.

Vladimir R. V. Assis; Mauro Copelli; Ronald Dickman

2011-06-16T23:59:59.000Z

197

Strongly anisotropic non-equilibrium phase transition in Ising models with friction  

E-Print Network (OSTI)

The non-equilibrium phase transition in driven two-dimensional Ising models with two different geometries is investigated using Monte Carlo methods as well as analytical calculations. The models show dissipation through fluctuation induced friction near the critical point. We first consider high driving velocities and demonstrate that both systems are in the same universality class and undergo a strongly anisotropic non-equilibrium phase transition, with anisotropy exponent \\theta=3. Within a field theoretical ansatz the simulation results are confirmed. The crossover from Ising to mean field behavior in dependency of system size and driving velocity is analyzed using crossover scaling. It turns out that for all finite velocities the phase transition becomes strongly anisotropic in the thermodynamic limit.

Sebastian Angst; Alfred Hucht; Dietrich E. Wolf

2012-01-10T23:59:59.000Z

198

Shell-model picture of virtual detour transitions in Ca41 radiative electron-capture decay  

Science Journals Connector (OSTI)

For the first forbidden unique (1u) radiative electron-capture ? decay of Ca41, a contribution of the ?/? detour transitions via virtual nuclear states to the bremsstrahlung spectrum has been considered in terms of the shell model. Calculations of the matrix elements for the virtual E1 ? and allowed Gamow-Teller ? transitions have been performed with the use of the Warburton, Becker, Millener, and Brown interactions. For the effective charge, which describes the contribution of the detour transitions, an interval 0.96model predictions are fairly close to the experimental value eeff=0.78. A possible origin of the small remaining deviation is discussed. © 1996 The American Physical Society.

J. L. ?ylicz; M. Pfützner; S. G. Rohozi?ski; B. A. Brown

1996-04-01T23:59:59.000Z

199

Dynamic modelling for thermal micro-actuators using thermal networks  

E-Print Network (OSTI)

Dynamic modelling for thermal micro-actuators using thermal networks Beatriz L´opez-Wallea,1 and analytical calculations. Key words: Micro-actuators, Thermal modelling, Electrical analogy, Thermal network 1 and MicroMechatronic Systems Department (AS2M), 24 rue Alain Savary, 25000 Besan¸con, France Abstract

Paris-Sud XI, Université de

200

Dynamic physiological modeling for functional diffuse optical tomography  

E-Print Network (OSTI)

,c and David A. Boasa a Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging and brain that reflect competing metabolic demands and cardiovascular dynamics. The diffuse nature of near- namic response. In this paper, we present a linear state-space model for DOT analysis that models

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

Computational Modeling of Brain Dynamics during Repetitive Head Motions  

E-Print Network (OSTI)

Computational Modeling of Brain Dynamics during Repetitive Head Motions Igor Szczyrba School motions in traumatic scenarios that are as- sociated with severe brain injuries. Our results are based on the linear Kelvin-Voigt brain injury model, which treats the brain matter as a viscoelastic solid, and on our

Burtscher, Martin

202

2 J. MANDEL ET AL. DYNAMIC DATA DRIVEN WILDFIRE MODELING  

E-Print Network (OSTI)

2 J. MANDEL ET AL. DYNAMIC DATA DRIVEN WILDFIRE MODELING J. MANDELa , M. CHENa , J.L. COENb , C of Colorado Denver, Denver, CO 80217-3364, USA b National Center for Atmospheric Research, Boulder, CO 80307. A proposed system for real-time modeling of wildfires is described. The system involves numerical weather

Douglas, Craig C.

203

Numerical Modeling of Brain Dynamics in Traumatic Situations -Impulsive Translations  

E-Print Network (OSTI)

.S.A. Abstract We numerically model the brain dy- namics during and after impulsive head translations using brain injuries appear among boxers and shaken babies despite minimal rotations of their heads. Modeling head translations also helps understand the brain dynamics during head rotations about an arbitrary

Burtscher, Martin

204

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

205

Dynamic model order reduction for shipboard integrated power systems  

Science Journals Connector (OSTI)

The shipboard integrated power system is modeled by a system of differential-algebraic equations with dynamics having time constants varying from fractions of a second to several minutes. Control and simulation of naval shipboard power systems for different ... Keywords: electric ship, integrated power system, model order reduction, shipboard power system, singular perturbation

Sudipta Lahiri; Dagmar Niebur; Harry Kwatny; Gaurav Bajpai

2009-07-01T23:59:59.000Z

206

Equivalence of Glass Transition and Colloidal Glass Transition in the Hard-Sphere Limit Thomas K. Haxton,2  

E-Print Network (OSTI)

Equivalence of Glass Transition and Colloidal Glass Transition in the Hard-Sphere Limit Ning Xu,1 that the slowing of the dynamics in simulations of several model glass-forming liquids is equivalent to the hard-sphere glass transition in the low-pressure limit. In this limit, we find universal behavior of the relaxation

Weeks, Eric R.

207

DYNAMICAL MODEL OF AN EXPANDING SHELL  

SciTech Connect

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

208

Friction in a Model of Hamiltonian Dynamics  

E-Print Network (OSTI)

We study the motion of a heavy tracer particle weakly coupled to a dense ideal Bose gas exhibiting Bose-Einstein condensation. In the so-called mean-field limit, the dynamics of this system approaches one determined by nonlinear Hamiltonian evolution equations describing a process of emission of Cerenkov radiation of sound waves into the Bose-Einstein condensate along the particle's trajectory. The emission of Cerenkov radiation results in a friction force with memory acting on the tracer particle and causing it to decelerate until it comes to rest.

Juerg Froehlich; Zhou Gang; Avy Soffer

2011-10-29T23:59:59.000Z

209

Recommendations for Development of Resilience-Based State-and-Transition Models D. D. Briske,1  

E-Print Network (OSTI)

Forum Recommendations for Development of Resilience-Based State-and-Transition Models D. D. Briske of Ecosystem Science and Management, Texas A&M University, 2138 TAMU, College Station, TX 77843, USA; 2, University of Nevada­Reno, Reno, NV 89557, USA; and 4 Rangeland Management Specialist, USDA-NRCS, West

210

Mathematical models of the transitions between endocrine therapy responsive and resistant states in breast cancer  

Science Journals Connector (OSTI)

...differential equations (SDEs) to...white noise process with where...the precise equations of the model...used for our simulations. In deriving...We used Matlab (v. 7...transition rate matrix. The off-diagonal...estimated by equation (2.9...Monte Carlo simulations, as functions...

2014-01-01T23:59:59.000Z

211

Modeling of Alpine Atmospheric Dynamics II  

E-Print Network (OSTI)

for large mesh sizes (x 20 km) to vertically redistribute heat and moisture in a grid column when model in a numerical model Convective cloud systems are not resolved if the mesh size of the grid is larger than small to treat convection as sub-grid scale process but too large to treat it explicitly For example

Gohm, Alexander

212

Dynamic force spectroscopy on multiple bonds: experiments and model  

E-Print Network (OSTI)

We probe the dynamic strength of multiple biotin-streptavidin adhesion bonds under linear loading using the biomembrane force probe setup for dynamic force spectroscopy. Measured rupture force histograms are compared to results from a master equation model for the stochastic dynamics of bond rupture under load. This allows us to extract the distribution of the number of initially closed bonds. We also extract the molecular parameters of the adhesion bonds, in good agreement with earlier results from single bond experiments. Our analysis shows that the peaks in the measured histograms are not simple multiples of the single bond values, but follow from a superposition procedure which generates different peak positions.

T. Erdmann; S. Pierrat; P. Nassoy; U. S. Schwarz

2007-12-18T23:59:59.000Z

213

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

SciTech Connect

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

214

Contour dynamics model for electric discharges  

Science Journals Connector (OSTI)

We present an effective contour model for electrical discharges deduced as the asymptotic limit of the minimal streamer model for the propagation of electric discharges, in the limit of small electron diffusion. The incorporation of curvature effects to the velocity propagation and not to the boundary conditions is a feature and makes it different from the classical Laplacian growth models. The dispersion relation for a nonplanar two-dimensional discharge is calculated. The development and propagation of fingerlike patterns are studied and their main features quantified.

M. Arrayás, M. A. Fontelos, and C. Jiménez

2010-03-18T23:59:59.000Z

215

Ice-water and liquid-vapor phase transitions by a Ginzburg–Landau model  

Science Journals Connector (OSTI)

A model for the first order phase transitions as ice-water and liquid-vapor is proposed using the Ginzburg–Landau equation for the order parameter ? . In this model the density ? is composed of two quantities ? 0 and ? 1 such that 1 / ? = 1 / ? 0 + 1 / ? 1 where ? 1 is strictly connected to the order parameter ? . By means of this decomposition we are able to represent the Andrew diagram without the use of the heuristic van der Waals equation.

Mauro Fabrizio

2008-01-01T23:59:59.000Z

216

Modeling Infection with Multi-agent Dynamics  

E-Print Network (OSTI)

Developing the ability to comprehensively study infections in small populations enables us to improve epidemic models and better advise individuals about potential risks to their health. We currently have a limited ...

Dong, Wen

2012-01-01T23:59:59.000Z

217

THE WISCONSIN DYNAMICAL/MICROPHYSICAL MODEL  

E-Print Network (OSTI)

, assumed uniform, is dictated by quasi-compressible computational stability requirements. The computational an ellipsoidal warm bubble in the lower central part of the model domain, with the same relative humidities

Wang, Pao K.

218

Tar Reforming in Model Gasifier Effluents: Transition Metal/Rare Earth Oxide Catalysts  

Science Journals Connector (OSTI)

Tar Reforming in Model Gasifier Effluents: Transition Metal/Rare Earth Oxide Catalysts ... So in this work we investigated the action of transition metal oxides (TMOs) other than Ni (e.g., Fe, Mn) mixed with REOs for tar reforming, at a medium temperature range (923–1073 K) and under conditions where direct reforming would dominate. ... The heated gas mixture passed through a 1/2” stainless steel tube containing 0.2–1 g of catalyst (40–60 mesh size) diluted with mullite and positioned between beds of ?-Al2O3. ...

Rui Li; Amitava Roy; Joseph Bridges; Kerry M. Dooley

2014-04-24T23:59:59.000Z

219

Zero gravity two-phase flow regime transition modeling compared with data and relap5-3d predictions  

E-Print Network (OSTI)

in the computer code do not scale to zero gravity. A new flow regime map is needed for zero gravity conditions. Three bubbly-to-slug transition models and four slug-to-annular transition models are analyzed and compared with the data. A mathematical method...

Ghrist, Melissa Renee

2009-05-15T23:59:59.000Z

220

Statistic inversion of multi-zone transition probability models for aquifer characterization in alluvial fans  

E-Print Network (OSTI)

Understanding the heterogeneity arising from the complex architecture of sedimentary sequences in alluvial fans is challenging. This paper develops a statistical inverse framework in a multi-zone transition probability approach for characterizing the heterogeneity in alluvial fans. An analytical solution of the transition probability matrix is used to define the statistical relationships among different hydrofacies and their mean lengths, integral scales, and volumetric proportions. A statistical inversion is conducted to identify the multi-zone transition probability models and estimate the optimal statistical parameters using the modified Gauss-Newton-Levenberg-Marquardt method. The Jacobian matrix is computed by the sensitivity equation method, which results in an accurate inverse solution with quantification of parameter uncertainty. We use the Chaobai River alluvial fan in the Beijing Plain, China, as an example for elucidating the methodology of alluvial fan characterization. The alluvial fan is divided...

Zhu, Lin; Gong, Huili; Gable, Carl; Teatini, Pietro

2015-01-01T23:59:59.000Z

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.


221

Asperity Model of an Earthquake - Dynamic Problem  

SciTech Connect

We develop an earthquake asperity model that explains previously determined empirical scaling relationships for repeating earthquakes along the San Andreas fault in central California. The model assumes that motion on the fault is resisted primarily by a patch of small strong asperities that interact with each other to increase the amount of displacement needed to cause failure. This asperity patch is surrounded by a much weaker fault that continually creeps in response to tectonic stress. Extending outward from the asperity patch into the creeping part of the fault is a shadow region where a displacement deficit exists. Starting with these basic concepts, together with the analytical solution for the exterior crack problem, the consideration of incremental changes in the size of the asperity patch leads to differential equations that can be solved to yield a complete static model of an earthquake. Equations for scalar seismic moment, the radius of the asperity patch, and the radius of the displacement shadow are all specified as functions of the displacement deficit that has accumulated on the asperity patch. The model predicts that the repeat time for earthquakes should be proportional to the scalar moment to the 1/6 power, which is in agreement with empirical results for repeating earthquakes. The model has two free parameters, a critical slip distance dc and a scaled radius of a single asperity. Numerical values of 0.20 and 0.17 cm, respectively, for these two parameters will reproduce the empirical results, but this choice is not unique. Assuming that the asperity patches are distributed on the fault surface in a random fractal manner leads to a frequency size distribution of earthquakes that agrees with the Gutenberg Richter formula and a simple relationship between the b-value and the fractal dimension. We also show that the basic features of the theoretical model can be simulated with numerical calculations employing the boundary integral method.

Johnson, Lane R.; Nadeau, Robert M.

2003-05-02T23:59:59.000Z

222

Dynamics of Ising models with damping  

Science Journals Connector (OSTI)

We show for the Ising model that it is possible to construct a discrete time stochastic model analogous to the Langevin equation that incorporates an arbitrary amount of damping. It is shown to give the correct equilibrium statistics and is then used to investigate nonequilibrium phenomena, in particular, magnetic avalanches. The value of damping can greatly alter the shape of hysteresis loops, and for small damping and high disorder, the morphology of large avalanches can be drastically affected. Small damping also alters the size distribution of avalanches at criticality.

J. M. Deutsch and A. Berger

2008-03-28T23:59:59.000Z

223

CSAW: a dynamical model of protein folding  

E-Print Network (OSTI)

CSAW (conditioned self-avoiding walk) is a model of protein folding that combines SAW (self-avoiding walk) with Monte-Carlo. It simulates the Brownian motion of a chain molecule in the presence of interactions, both among chain residues, and with the environment. In a first model that includes the hydrophobic effect and hydrogen bonding, a chain of 30 residues folds into a native state with stable secondary and tertiary structures. The process starts with a rapid collapse into an intermediate "molten globule", which slowly decays into the native state afer a relatively long quiescent period. The behavior of the radius of gyration mimics experimental data.

Kerson Huang

2006-01-12T23:59:59.000Z

224

Clustering properties of dynamical dark energy models  

SciTech Connect

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 nonminimally coupled to dark matter.

Avelino, P. P.; Beca, L. M. G. [Centro de Fisica do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Departamento de Fisica da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Martins, C. J. A. P. [Centro de Astrofisica, Universidade do Porto, Rua das Estrelas s/n, 4150-762 Porto (Portugal); DAMTP, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

2008-05-15T23:59:59.000Z

225

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.

226

Hydrodynamic modeling of the deconfinement phase transition in heavy-ion collisions in the NICA–FAIR energy domain  

Science Journals Connector (OSTI)

We use (3 + 1) dimensional ideal hydrodynamics to describe the space-time evolution of strongly interacting matter created in Au + Au and Pb + Pb collisions. The model is applied for the domain of bombarding energies 1–160 GeV/nucleon which includes future NICA (Dubna) and FAIR (Darmstadt) experiments. Two equations of state are used, the first one corresponding to resonance hadron gas and the second one including the deconfinement phase transition. The initial state is represented by two Lorentz-boosted nuclei. Dynamic trajectories of matter in the central box of the system are analyzed. They can be well represented by a fast shock-wave compression followed by a relatively slow isentropic expansion. The parameters of collective flows and hadronic spectra are calculated under assumption of the isochronous freeze-out. It is shown that the deconfinement phase transition leads to broadening of proton rapidity distributions, increase of elliptic flows, and formation of the directed antiflow in the central rapidity region. These effects are most pronounced at bombarding energies around 10 GeV/nucleon, when the system spends the longest time in the mixed phase. From the comparison with three-fluid calculations we conclude that the transparency effects are not so important in central collisions at NICA–FAIR energies (below 30 GeV/nucleon).

A. V. Merdeev; L. M. Satarov; I. N. Mishustin

2011-07-29T23:59:59.000Z

227

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-Print Network (OSTI)

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

Raymond E. Goldstein

2014-09-08T23:59:59.000Z

228

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-Print Network (OSTI)

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these re...

Goldstein, Raymond E

2014-01-01T23:59:59.000Z

229

The Community Surface Dynamics Modeling System: Experiences on Building a Collaborative Modeling Platform  

E-Print Network (OSTI)

The Community Surface Dynamics Modeling System: Experiences on Building a Collaborative Modeling VOLUNTEERISM MANY DEVELOPERS Grand Challenge: Building a Toolbox of Component Models with guidance and input Members and Governance · Tools for Collaboration 1) CSDMS Wiki 2) CSDMS Modeling Tool · Strategies

Wright, Dawn Jeannine

230

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations  

E-Print Network (OSTI)

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations J 2004) An ad hoc thermostating procedure that couples a molecular dynamics (MD) simulation

Brenner, Donald W.

231

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

SciTech Connect

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

232

A Dynamical Model of Plasma Turbulence in the Solar Wind  

E-Print Network (OSTI)

A dynamical approach, rather than the usual statistical approach, is taken to explore the physical mechanisms underlying the nonlinear transfer of energy, the damping of the turbulent fluctuations, and the development of coherent structures in kinetic plasma turbulence. It is argued that the linear and nonlinear dynamics of Alfven waves are responsible, at a very fundamental level, for some of the key qualitative features of plasma turbulence that distinguish it from hydrodynamic turbulence, including the anisotropic cascade of energy and the development of current sheets at small scales. The first dynamical model of kinetic turbulence in the weakly collisional solar wind plasma that combines self-consistently the physics of Alfven waves with the development of small-scale current sheets is presented and its physical implications are discussed. This model leads to a simplified perspective on the nature of turbulence in a weakly collisional plasma: the nonlinear interactions responsible for the turbulent casca...

Howes, G G

2015-01-01T23:59:59.000Z

233

Modeling Dynamic Landscapes in Open Source GIS  

E-Print Network (OSTI)

differencing, per-cell statistics: core, envelope, rate of change Space-Time voxel model V o lu m e s S u rf a c e s L in e s 2011 2004 1999 Helena Mitasova, NCSU DEM processing Series of point clouds interpolated to 0.3m-1m DEMs Systematic errors... to Doug Newcomb and Hope Morgan for sharing the data RTKGPS 2001 Lidar 0.2m lower Helena Mitasova, NCSU Nags Head Raster-based analysis Core surface z-min for each cell Envelope surface z-max for each cell Shoreline band: defined by shoreline from core...

Mitasova, Helena

2013-11-20T23:59:59.000Z

234

Insights gained from solvable models into a variety of phase transitions, including emergent assemblies plus isoelectronic series of atomic ions  

E-Print Network (OSTI)

Three solvable models are set out in some detail in reviewing different types of phase transitions. Two of these relate directly to emergent critical phenomena, viz. melting and magnetic transitions in heavy rare-earth metals, and secondly, via the $3d$ Ising model, to critical behaviour in an insulating ferromagnet such as CrBr$_3$. The final `transition', however, concerns ionization of an electron in an isoelectronic series with $N$ electrons as the atomic number $Z$ is reduced below that of the neutral atom. These solvable models are, throughout, brought into contact either with experiment, or with very precise numerical modelling on real materials.

March, N H; Pucci, R

2014-01-01T23:59:59.000Z

235

Wind Energy Applications of Unified and Dynamic Turbulence Models  

E-Print Network (OSTI)

Wind Energy Applications of Unified and Dynamic Turbulence Models Stefan Heinz and Harish Gopalan applicable as a low cost alternative. 1 Introduction There is a growing interest in using wind energy suggests the possibility of providing 20% of the electricity in the U.S. by wind energy in 2030

Heinz, Stefan

236

A Bayesian Dynamic Model for Influenza Surveillance Paola Sebastiani  

E-Print Network (OSTI)

by the increasing number of outbreaks caused by the H5N1 bird-flu strain [10]. Because influenza viruses changeA Bayesian Dynamic Model for Influenza Surveillance Paola Sebastiani Kenneth D Mandl Peter, the growing fear of an influenza pandemic and the recent shortage of flu vaccine highlight the need

Szolovits, Peter

237

Multiscale modeling of polystyrene dynamics in different environments  

E-Print Network (OSTI)

Multiscale modeling of polystyrene dynamics in different environments Qi Sun1 , Florence Pon1 simulations can address not only the average properties of the system but also the distribution over any component in their neighborhood and vice versa. The simulation temperature of 450 K is chosen to be above

Faller, Roland

238

A Model for Dynamic Reconfiguration in Service-oriented Architectures  

E-Print Network (OSTI)

A Model for Dynamic Reconfiguration in Service-oriented Architectures Jos´e Luiz Fiadeiro1 and Ant of service-oriented applications goes be- yond what is currently addressed by existing architecture of service-oriented applications. 1 Introduction Several architectural aspects arise from service-oriented

Lopes, Antónia

239

DYNAMIC MODELLING OF AUTONOMOUS POWER SYSTEMS INCLUDING RENEWABLE POWER SOURCES.  

E-Print Network (OSTI)

(thermal, gas, diesel) and renewable (hydro, wind) power units. The objective is to assess the impact - that have a special dynamic behaviour, and the wind turbines. Detailed models for each one of the power system components are developed. Emphasis is given in the representation of different hydro power plant

Paris-Sud XI, Université de

240

Dynamic Modeling and Recipe Optimization of Polyether Polyol Processes  

E-Print Network (OSTI)

Dynamic Modeling and Recipe Optimization of Polyether Polyol Processes Fall 2012 EWO Meeting Yisu Monomer Reactor Basic procedures Starters are first mixed with catalyst in the liquid phase Alkylene oxides in the liquid phase are fed in controlled rates The reactor temperature is controlled by the heat

Grossmann, Ignacio E.

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

FRW Cosmological model with Modified Chaplygin Gas and Dynamical System  

E-Print Network (OSTI)

The Friedmann-Robertson-Walker(FRW) model with dynamical Dark Energy(DE) in the form of modified Chaplygin gas(MCG) has been investigated. The evolution equations are reduced to an autonomous system on the two dimensional phase plane and it can be interpreted as the motion of the particle in an one dimensional potential.

Nairwita Mazumder; Ritabrata Biswas; Subenoy Chakraborty

2011-06-23T23:59:59.000Z

242

Reverse Audio Engineering: Model-Based Inversion of Dynamic Range  

E-Print Network (OSTI)

1 Reverse Audio Engineering: Model-Based Inversion of Dynamic Range Compression Stanislaw Gorlow, Graduate Student Member, IEEE and Joshua D. Reiss, Member, IEEE Abstract--Reverse audio engineering so far, reverse audio engineering. I. INTRODUCTION SOUND or audio engineering is an established discipline

243

Blue Dots Team Transits Working Group Review  

E-Print Network (OSTI)

Transiting planet systems offer an unique opportunity to observationally constrain proposed models of the interiors (radius, composition) and atmospheres (chemistry, dynamics) of extrasolar planets. The spectacular successes of ground-based transit surveys (more than 60 transiting systems known to-date) and the host of multi-wavelength, spectro-photometric follow-up studies, carried out in particular by HST and Spitzer, have paved the way to the next generation of transit search projects, which are currently ongoing (CoRoT, Kepler), or planned. The possibility of detecting and characterizing transiting Earth-sized planets in the habitable zone of their parent stars appears tantalizingly close. In this contribution we briefly review the power of the transit technique for characterization of extrasolar planets, summarize the state of the art of both ground-based and space-borne transit search programs, and illustrate how the science of planetary transits fits within the Blue Dots perspective.

Sozzetti, A; Alonso, R; Blank, D L; Catala, C; Deeg, H; Grenfell, J L; Hellier, C; Latham, D W; Minniti, D; Pont, F; Rauer, H

2009-01-01T23:59:59.000Z

244

Disassembly of projectile remnants in a simple dynamics and statistics model  

Science Journals Connector (OSTI)

The ALADIN data for the disassembly of projectile remnants in Au+Au reactions at 600A?MeV are investigated using a simple dynamics and statistics model. Once the model parameter relevant to the excitation energy is fixed via fitting one datum point in the experimental correlation curve between the mean multiplicity of IMF and the Zbound, not only this full correlation curve but also all the experimental charge correlations are reproduced nicely. The data of the size of projectile remnant and of the excitation energy per nucleon as functions of Zbound are reproduced as well. Meanwhile, the theoretical relative yield of the decay mode of projectile remnant as a function of Zbound is comparable with the experimental ones. In addition, the theoretical caloric curve of projectile remnants is also similar to the ALADIN ones. However, it is premature to conclude that the ALADIN caloric curve is relating to the liquid-gas phase transition.

Sa Ben-Hao; Zheng Yu-Ming; Wang Hui; Zhang Xiao-Ze

1998-08-01T23:59:59.000Z

245

Dynamo Onset as a First-Order Transition: Lessons from a Shell Model for Magnetohydrodynamics  

E-Print Network (OSTI)

We carry out systematic and high-resolution studies of dynamo action in a shell model for magnetohydrodynamic (MHD) turbulence over wide ranges of the magnetic Prandtl number $Pr_{\\rm M}$ and the magnetic Reynolds number $Re_{\\rm M}$. Our study suggests that it is natural to think of dynamo onset as a nonequilibrium, first-order phase transition between two different turbulent, but statistically steady, states. The ratio of the magnetic and kinetic energies is a convenient order parameter for this transition. By using this order parameter, we obtain the stability diagram (or nonequilibrium phase diagram) for dynamo formation in our MHD shell model in the $(Pr^{-1}_{\\rm M}, Re_{\\rm M})$ plane. The dynamo boundary, which separates dynamo and no-dynamo regions, appears to have a fractal character. We obtain hysteretic behavior of the order parameter across this boundary and suggestions of nucleation-type phenomena.

Ganapati Sahoo; Dhrubaditya Mitra; Rahul Pandit

2009-11-23T23:59:59.000Z

246

Dynamo Onset as a First-Order Transition: Lessons from a Shell Model for Magnetohydrodynamics  

E-Print Network (OSTI)

We carry out systematic and high-resolution studies of dynamo action in a shell model for magnetohydrodynamic (MHD) turbulence over wide ranges of the magnetic Prandtl number $Pr_{\\rm M}$ and the magnetic Reynolds number $Re_{\\rm M}$. Our study suggests that it is natural to think of dynamo onset as a nonequilibrium, first-order phase transition between two different turbulent, but statistically steady, states. The ratio of the magnetic and kinetic energies is a convenient order parameter for this transition. By using this order parameter, we obtain the stability diagram (or nonequilibrium phase diagram) for dynamo formation in our MHD shell model in the $(Pr^{-1}_{\\rm M}, Re_{\\rm M})$ plane. The dynamo boundary, which separates dynamo and no-dynamo regions, appears to have a fractal character. We obtain hysteretic behavior of the order parameter across this boundary and suggestions of nucleation-type phenomena.

Sahoo, Ganapati; Pandit, Rahul

2009-01-01T23:59:59.000Z

247

Quantum phase transitions in exactly solvable one-dimensional compass models  

E-Print Network (OSTI)

We present an exact solution for a class of one-dimensional compass models which stand for interacting orbital degrees of freedom in a Mott insulator. By employing the Jordan-Wigner transformation we map these models on noninteracting fermions and discuss how spin correlations, high degeneracy of the ground state, and $Z_2$ symmetry in the quantum compass model are visible in the fermionic language. Considering a zigzag chain of ions with singly occupied $e_g$ orbitals ($e_g$ orbital model) we demonstrate that the orbital excitations change qualitatively with increasing transverse field, and that the excitation gap closes at the quantum phase transition to a polarized state. This phase transition disappears in the quantum compass model with maximally frustrated orbital interactions which resembles the Kitaev model. Here we find that finite transverse field destabilizes the orbital-liquid ground state with macroscopic degeneracy, and leads to peculiar behavior of the specific heat and orbital susceptibility at finite temperature. We show that the entropy and the cooling rate at finite temperature exhibit quite different behavior near the critical point for these two models.

Wen-Long You; Peter Horsch; Andrzej M. Ole?

2014-03-21T23:59:59.000Z

248

Core-crust transition properties of neutron stars within systematically varied extended relativistic mean-field model  

E-Print Network (OSTI)

The model dependence and the symmetry energy dependence of the core-crust transition properties for the neutron stars are studied using three different families of systematically varied extended relativistic mean field model. Several forces within each of the families are so considered that they yield wide variations in the values of the nuclear symmetry energy $a_{\\rm sym}$ and its slope parameter $L$ at the saturation density. The core-crust transition density is calculated using a method based on random-phase-approximation. The core-crust transition density is strongly correlated, in a model independent manner, with the symmetry energy slope parameter evaluated at the saturation density. The pressure at the transition point dose not show any meaningful correlations with the symmetry energy parameters at the saturation density. At best, pressure at the transition point is correlated with the symmetry energy parameters and their linear combination evaluated at the some sub-saturation density. Yet, such corre...

Sulaksono, A; Agrawal, B K

2014-01-01T23:59:59.000Z

249

Model equations in rarefied gas dynamics: Viscous-slip and thermal-slip coefficients  

E-Print Network (OSTI)

Model equations in rarefied gas dynamics: Viscous-slip and thermal-slip coefficients C. E. Siewert-slip and the thermal-slip coefficients in rarefied gas dynamics. More specifically, the BGK model, the S model In reviewing numerous papers devoted to model equa- tions in rarefied gas dynamics, we have found no definitive

Siewert, Charles E.

250

Coupling Lattice Boltzmann and Molecular Dynamics models for dense fluids  

E-Print Network (OSTI)

We propose a hybrid model, coupling Lattice Boltzmann and Molecular Dynamics models, for the simulation of dense fluids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The MD and LB formulations communicate via the exchange of velocities and velocity gradients at the interface. We validate the present LB-MD model in simulations of flows of liquid argon past and through a carbon nanotube. Comparisons with existing hybrid algorithms and with reference MD solutions demonstrate the validity of the present approach.

A. Dupuis; E. M. Kotsalis; P. Koumoutsakos

2006-10-27T23:59:59.000Z

251

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

252

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

253

A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin  

E-Print Network (OSTI)

A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin Report Prepared by using tools such as tracers to determine groundwater travel times and this dynamic simulation modeling

Fay, Noah

254

Library for modeling and simulating the thermal dynamics of buildings  

Science Journals Connector (OSTI)

Today's buildings consume more energy than any other sector of the U.S. economy, including transportation and industry; a similar importance can be expected in most European countries. Due to the increased interest in saving energy in buildings, new dynamic thermal models that describe transient response in more flexible modeling languages become necessary. Traditional building simulation software (e.g. TRNSYS or Energy Plus) are based on almost intractable simulation codes, difficult to maintain and modify, that predict system quantities at fixed time intervals. More clear code, properly separated from the simulation environment, with variable time step solvers would be necessary for the assessment of HVAC system performance with quicker dynamics. Following some ideas from a previous building thermal behavior library, a new enhanced Modelica library for modeling buildings is presented. The library basically consists of a combination of lumped parameter models and one-dimensional distributed parameter models that interconnects with each other through a set of common interfaces. Object-oriented features like class parameters and multiple-inheritance are used to improve the library structure making it easy to read and use. Complex building topologies can be built-up from component blocks that result in physically correct compound models that can be efficiently simulated and studied in any Modelica simulation environment.

Juan I. Videla; Bernt Lie

2006-01-01T23:59:59.000Z

255

Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model  

Science Journals Connector (OSTI)

...Copyright (c) 1971 Progress of Theoretical Physics March 1971 letter Letters to the Editor Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model Yositaka Onodera Department......

Yositaka Onodera

1971-03-01T23:59:59.000Z

256

Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model  

Science Journals Connector (OSTI)

...Copyright (c) 1976 Progress of Theoretical Physics March 1976 correction Errata Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model Yositaka Onodera The......

Yositaka Onodera

1976-03-01T23:59:59.000Z

257

Dynamical Reduction Models: present status and future developments  

E-Print Network (OSTI)

We review the major achievements of the dynamical reduction program, showing why and how it provides a unified, consistent description of physical phenomena, from the microscopic quantum domain to the macroscopic classical one. We discuss the difficulties in generalizing the existing models in order to comprise also relativistic quantum field theories. We point out possible future lines of research, ranging from mathematical physics to phenomenology.

A. Bassi

2007-02-08T23:59:59.000Z

258

Modeling biofuel expansion effects on land use change dynamics  

Science Journals Connector (OSTI)

Increasing demand for crop-based biofuels, in addition to other human drivers of land use, induces direct and indirect land use changes (LUC). Our system dynamics tool is intended to complement existing LUC modeling approaches and to improve the understanding of global LUC drivers and dynamics by allowing examination of global LUC under diverse scenarios and varying model assumptions. We report on a small subset of such analyses. This model provides insights into the drivers and dynamic interactions of LUC (e.g., dietary choices and biofuel policy) and is not intended to assert improvement in numerical results relative to other works.Demand for food commodities are mostly met in high food and high crop-based biofuel demand scenarios, but cropland must expand substantially. Meeting roughly 25% of global transportation fuel demand by 2050 with biofuels requires >2 times the land used to meet food demands under a presumed 40% increase in per capita food demand. In comparison, the high food demand scenario requires greater pastureland for meat production, leading to larger overall expansion into forest and grassland. Our results indicate that, in all scenarios, there is a potential for supply shortfalls, and associated upward pressure on prices, of food commodities requiring higher land use intensity (e.g., beef) which biofuels could exacerbate.

Ethan Warner; Daniel Inman; Benjamin Kunstman; Brian Bush; Laura Vimmerstedt; Steve Peterson; Jordan Macknick; Yimin Zhang

2013-01-01T23:59:59.000Z

259

Best practices for system dynamics model design and construction with powersim studio.  

SciTech Connect

This guide addresses software quality in the construction of Powersim{reg_sign} Studio 8 system dynamics simulation models. It is the result of almost ten years of experience with the Powersim suite of system dynamics modeling tools (Constructor and earlier Studio versions). It is a guide that proposes a common look and feel for the construction of Powersim Studio system dynamics models.

Malczynski, Leonard A.

2011-06-01T23:59:59.000Z

260

Modelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models  

E-Print Network (OSTI)

Modelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models (2004)). Large multi­city studies such as `Air pollution and health: a European approach' (APHEA across a number of US and European cities. Short­term e#ects of air pollution on health are estimated

Bath, University of

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

Non-equilibrium phase transition in an exactly solvable driven Ising model with friction  

E-Print Network (OSTI)

A driven Ising model with friction due to magnetic correlations has recently been proposed by Kadau et al. (Phys. Rev. Lett. 101, 137205 (2008)). The non-equilibrium phase transition present in this system is investigated in detail using analytical methods as well as Monte Carlo simulations. In the limit of high driving velocities $v$ the model shows mean field behavior due to dimensional reduction and can be solved exactly for various geometries. The simulations are performed with three different single spin flip rates: the common Metropolis and Glauber rates as well as a multiplicative rate. Due to the non-equilibrium nature of the model all rates lead to different critical temperatures at $v>0$, while the exact solution matches the multiplicative rate. Finally, the cross-over from Ising to mean field behavior as function of velocity and system size is analysed in one and two dimensions.

Alfred Hucht

2009-09-02T23:59:59.000Z

262

User Guide for PV Dynamic Model Simulation Written on PSCAD Platform  

SciTech Connect

This document describes the dynamic photovoltaic model developed by the National Renewable Energy Laboratory and is intended as a guide for users of these models.

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

2014-11-01T23:59:59.000Z

263

Pseudocrystalline model of the magnetic anisotropy in amorphous rare-earth–transition-metal thin films  

Science Journals Connector (OSTI)

A pseudocrystalline model is proposed to explain the occurrence of perpendicular anisotropy in amorphous rare-earth–transition metal (R-T) thin films. It is based on the central hypothesis that during layer-by-layer growth small planar hexagonal units are formed defining on average a preferential axis perpendicular to the film plane. The units are similar in structure to relaxed crystalline ones and are estimated to typically comprise six rare-earth atoms. They are regarded as an idealized model of the short-range order and are consistent with the known nearest-neighbor R-T and T-T coordination numbers in the amorphous state. This model is able to explain the known experimental results concerning the influence of composition, substrate temperature, annealing, and bombardment effects during sputter deposition on the magnetic anisotropy of thin amorphous rare-earth–transition-metal films of the system (Nd, Tb, Dy) (Fe, Co), as well as the destruction of this anisotropy by additives.

D. Mergel; H. Heitmann; P. Hansen

1993-01-01T23:59:59.000Z

264

Phase transitions in a holographic s+p model with backreaction  

E-Print Network (OSTI)

In a previous paper (arXiv:1309.2204, JHEP 1311 (2013) 087), we present a holographic s+p superconductor model with a scalar triplet charged under an SU(2) gauge field in the bulk and study the competition and coexistence of the s-wave and p-wave orders in the probe limit. In this work we continue to study the model by considering the full back reaction. The model shows a rich phase structure and various condensate behaviors such as the "n-type" and "u-type" ones. The phase transitions to the p-wave phase or s+p coexisting phase become first order in strongly back reacted cases. In these first order phase transitions, the free energy curve always forms a swallow tail shape, in which the unstable s+p solution can also play an important role. The phase diagrams of this system are given in terms of the dimension of the scalar order and the temperature in the cases of eight different values of the back reaction parameter, which show that the region for the s+p coexisting phase is enlarged with a small or medium b...

Nie, Zhang-Yu; Gao, Xin; Li, Li; Zeng, Hui

2015-01-01T23:59:59.000Z

265

The piston-flow interaction as a model for the deflagration-to-detonation transition  

SciTech Connect

The piston-flow interaction induced by a piston pushing hydraulically resisted gas through a long tube is discussed. It is shown that the hydraulic resistance causes a significant precompression and preheating of the gas adjacent to the piston's edge. In the case of an explosive premixture this development may lead to a localized autoignition triggering detonation. It is suggested that the problem may serve as a guide for understanding the deflagration-to-detonation transition in tubes, with the piston modeling the impact of the advancing flame. (author)

Brailovsky, Irina; Kagan, Leonid; Sivashinsky, Gregory [Sackler Faculty of Exact Sciences, School of Mathematical Sciences, Tel Aviv University (Israel)

2011-01-15T23:59:59.000Z

266

Analytic estimation of the Lyapunov exponent in a mean-field model undergoing a phase transition  

Science Journals Connector (OSTI)

The parametric instability contribution to the largest Lyapunov exponent ?1 is derived for a mean-field Hamiltonian model, with attractive long-range interactions. This uses a recent Riemannian approach to describe Hamiltonian chaos with a large number N of degrees of freedom. Through microcanonical estimates of suitable geometrical observables, the mean-field behavior of ?1 is analytically computed and related to the second-order phase transition undergone by the system. It predicts that chaoticity drops to zero at the critical temperature and remains vanishing above it, with ?1 scaling as N-(1/3) to the leading order in N.

Marie-Christine Firpo

1998-06-01T23:59:59.000Z

267

Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)  

SciTech Connect

Eulerian hydrocode simulations utilizing the Mechanical Threshold Stress flow stress model were performed to provide insight into a dynamic extrusion experiment. The dynamic extrusion response of copper (three different grain sizes) and tantalum spheres were simulated with MESA, an explicit, 2-D Eulerian continuum mechanics hydrocode and compared with experimental data. The experimental data consisted of high-speed images of the extrusion process, recovered extruded samples, and post test metallography. The hydrocode was developed to predict large-strain and high-strain-rate loading problems. Some of the features of the features of MESA include a high-order advection algorithm, a material interface tracking scheme and a van Leer monotonic advection-limiting. The Mechanical Threshold Stress (MTS) model was utilized to evolve the flow stress as a function of strain, strain rate and temperature for copper and tantalum. Plastic strains exceeding 300% were predicted in the extrusion of copper at 400 m/s, while plastic strains exceeding 800% were predicted for Ta. Quantitative comparisons between the predicted and measured deformation topologies and extrusion rate were made. Additionally, predictions of the texture evolution (based upon the deformation rate history and the rigid body rotations experienced by the copper during the extrusion process) were compared with the orientation imaging microscopy measurements. Finally, comparisons between the calculated and measured influence of the initial texture on the dynamic extrusion response of tantalum was performed.

Burkett, Michael W [Los Alamos National Laboratory; Clancy, Sean P [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

268

Dynamics of iron atoms across the pressure-induced Invar transition in Pd{sub 3}Fe.  

SciTech Connect

The {sup 57}Fe phonon partial density of states (PDOS) in L1{sub 2}-ordered Pd{sub 3}Fe was studied at high pressures by nuclear resonant inelastic x-ray scattering (NRIXS) measurements and density functional theory (DFT) calculations. The NRIXS spectra showed that the stiffening of the {sup 57}Fe PDOS with decreasing volume was slower from 12 to 24 GPa owing to the pressure-induced Invar transition in Pd{sub 3}Fe, with a change from a high-moment ferromagnetic (FM) state to a low-moment (LM) state observed by nuclear forward scattering. Force constants obtained from fitting to a Born-von Karman model showed a relative softening of the first-nearest-neighbor (1NN) Fe-Pd longitudinal force constants at the magnetic transition. For the FM low-pressure state, the DFT calculations gave a PDOS and 1NN longitudinal force constants in good agreement with experiment, but discrepancies for the high-pressure LM state suggest the presence of short-range magnetic order.

Winterrose, M. L.; Mauger, L.; Halevy, I.; Yue, A. F.; Lucas, M. S.; Munoz, J. A.; Tan, H.; Xiao, Y.; Chow, P.; Sturhahn, W.; Toellner, T.S.; Alp, E. E.; Fultz, B. (X-Ray Science Division); (California Inst. of Tech.); (Carnegie Inst. of Wasington)

2011-04-01T23:59:59.000Z

269

Equilibrium roughening transition in a one-dimensional modified sine-Gordon model Grupo Interdisciplinar de Sistemas Complejos (GISC) and Departamento de Matemticas, Universidad Carlos III de Madrid,  

E-Print Network (OSTI)

Equilibrium roughening transition in a one-dimensional modified sine-Gordon model Saúl Ares* Grupo-Gordon model that exhibits a thermodynamic, roughening phase transition, in analogy with the two-dimensional and that it has a true phase transition makes it an ideal framework for further studies of roughening phase

Sánchez, Angel "Anxo"

270

Dynamic ModelingDynamic Modeling the Electric Power Networkthe Electric Power Network  

E-Print Network (OSTI)

criteria to enter the wholesale market DEREGULATION PROCESS: FERC's Order 888 mandated the wheeling at the National Energy Modeling System/Annual Energy Outlook Conference, Washington, DC, March 10, 2003] #12

Oro, Daniel

271

Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance Models  

E-Print Network (OSTI)

ARTICLES Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance metabolism with dynamic mass balances on key extracellular species. Model-based dynamic optimization concentration profiles, and the final batch time are treated as decision variables in the dynamic optimization

Mountziaris, T. J.

272

Indicators to support the dynamic evaluation of air quality models  

Science Journals Connector (OSTI)

Abstract Air quality models are useful tools for the assessment and forecast of pollutant concentrations in the atmosphere. Most of the evaluation process relies on the “operational phase” or in other words the comparison of model results with available measurements which provides insight on the model capability to reproduce measured concentrations for a given application. But one of the key advantages of air quality models lies in their ability to assess the impact of precursor emission reductions on air quality levels. Models are then used in a dynamic mode (i.e. response to a change in a given model input data) for which evaluation of the model performances becomes a challenge. The objective of this work is to propose common indicators and diagrams to facilitate the understanding of model responses to emission changes when models are to be used for policy support. These indicators are shown to be useful to retrieve information on the magnitude of the locally produced impacts of emission reductions on concentrations with respect to the “external to the domain” contribution but also to identify, distinguish and quantify impacts arising from different factors (different precursors). In addition information about the robustness of the model results is provided. As such these indicators might reveal useful as first screening methodology to identify the feasibility of a given action as well as to prioritize the factors on which to act for an increased efficiency. Finally all indicators are made dimensionless to facilitate the comparison of results obtained with different models, different resolutions, or on different geographical areas.

P. Thunis; A. Clappier

2014-01-01T23:59:59.000Z

273

Dynamics of popstar record sales on phonographic market -- stochastic model  

E-Print Network (OSTI)

We investigate weekly record sales of the world's most popular 30 artists (2003-2013). Time series of sales have non-trivial kind of memory (anticorrelations, strong seasonality and constant autocorrelation decay within 120 weeks). Amount of artists record sales are usually the highest in the first week after premiere of their brand new records and then decrease to fluctuate around zero till next album release. We model such a behavior by discrete mean-reverting geometric jump diffusion (MRGJD) and Markov regime switching mechanism (MRS) between the base and the promotion regimes. We can built up the evidence through such a toy model that quantifies linear and nonlinear dynamical components (with stationary and nonstationary parameters set), and measure local divergence of the system with collective behavior phenomena. We find special kind of disagreement between model and data for Christmas time due to unusual shopping behavior. Analogies to earthquakes, product life-cycles, and energy markets will also be d...

Jarynowski, Amdrzej

2013-01-01T23:59:59.000Z

274

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

275

Dynamic validated model of a DFIG wind turbine  

Science Journals Connector (OSTI)

This paper presents the development and qualitative validation of a doubly-fed induction generator (DFIG) wind turbine model that is represented in terms of behaviour equations of each of the subsystems, mainly the turbine rotor, the drive train, the induction generator, the power converters and associated control systems and a protection system. Simulation results obtained from the models are compared to the field measurement data in a qualitative manner due to rotor wake and lack of ability of a single anemometer for adequate measurement of wind speed acting on the large surface of the rotor. It is concluded that the model is reasonably accurate and can hence be used for representing wind turbines in power system dynamics simulations.

Md. Ayaz Chowdhury; Nasser Hosseinzadeh; Weixiang Shen

2014-01-01T23:59:59.000Z

276

Explorations in combining cognitive models of individuals and system dynamics models of groups.  

SciTech Connect

This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

Backus, George A.

2008-07-01T23:59:59.000Z

277

Bulk viscosity and the phase transition of the linear sigma model  

E-Print Network (OSTI)

In this work we deal with the critical behavior of the bulk viscosity in the linear sigma model (LSM) as an example of a system which can be treated by using different techniques. Starting from the Boltzmann-Uehling-Uhlenbeck equation we compute the bulk viscosity over entropy density of the LSM in the large-N limit. We search for a possible maximum of the bulk viscosity over entropy density at the critical temperature of the chiral phase transition. The information about this critical temperature, as well as the effective masses, is obtained from the effective potential. We find that the expected maximum (as a measure of the conformality loss) is absent in the large N in agreement with other models in the same limit. However, this maximum appears when, instead of the large-N limit, the Hartree approximation within the Cornwall-Jackiw-Tomboulis (CJT) formalism is used. Nevertheless, this last approach to the LSM does not give rise to the Goldstone theorem and also predicts a first order phase transition instead of the expected second order one. Therefore both, the large-N limit and the CJT-Hartree approximations, should be considered as complementary for the study of the critical behavior of the bulk viscosity in the LSM.

Antonio Dobado; Juan M. Torres-Rincon

2012-06-06T23:59:59.000Z

278

Modeling phase transitions during the crystallization of a multicomponent fat under shear  

Science Journals Connector (OSTI)

The crystallization of multicomponent systems involves several competing physicochemical processes that depend on composition, temperature profiles, and shear rates applied. Research on these mechanisms is necessary in order to understand how natural materials form crystalline structures. Palm oil was crystallized in a Couette cell at 17 and 22°C under shear rates ranging from 0to2880s?1 at a synchrotron beamline. Two-dimensional x-ray diffraction patterns were captured at short time intervals during the crystallization process. Radial analysis of these patterns showed shear-induced acceleration of the phase transition from ? to ??. This effect can be explained by a simple model where the ? phase nucleates from the melt, a process which occurs independently of shear rate. The ? phase grows according to an Avrami growth model. The ?? phase nucleates on the ? crystallites, with the amount of ?? crystal formation dependent on the rate of transformation of ? to ?? as well as the growth rate of the ?? phase from the melt. The shear induced ?-?? phase transition acceleration occurs because under shear, the ? nuclei form many distinct small crystallites which can easily transform to the ?? form, while at lower shear rates, the ? nuclei tend to aggregate, thus retarding the nucleation of the ?? crystals. The displacement of the diffraction peak positions revealed that increased shear rate promotes the crystallization of the higher melting fraction, affecting the composition of the crystallites. Crystalline orientation was observed only at shear rates above 180s?1 at 17°C and 720s?1 at 22°C.

Gianfranco Mazzanti; Alejandro G. Marangoni; Stefan H. J. Idziak

2005-04-25T23:59:59.000Z

279

Electroweak phase transition in the economical 3-3-1 model  

E-Print Network (OSTI)

Following our approach to the electroweak phase transition (EWPT) in our previous work, we consider the EWPT in the economical 3-3-1 (E331) model. Our analysis shows that the EWPT in the model is a sequence of two first-order phase transitions, $SU(3) \\rightarrow SU(2)$ at the TeV scale and $SU(2) \\rightarrow U(1)$ at the $100$ GeV scale. \\textbf{The EWPT $SU(3) \\rightarrow SU(2)$ is triggered by the new bosons and the exotic quarks; its strength is about $1 - 13$ if the mass ranges of these new particles are $10^2 \\,\\mathrm{GeV} - 10^3 \\,\\mathrm{GeV}$. The EWPT $SU(2) \\rightarrow SU(1)$ is strengthened by only the new bosons; its strength is about $1 - 1.15$ if the mass parts of $H^0_1$, $H^\\pm_2$ and $Y^\\pm$ are in the ranges $10 \\,\\mathrm{GeV} - 10^2 \\,\\mathrm{GeV}$. The contributions of $H^0_1$ and $H^{\\pm}_2$ to the strengths of both EWPTs may make them sufficiently strong to provide large deviations from thermal equilibrium and B violation necessary for baryogenesis.

Vo Quoc Phong; Hoang Ngoc Long; Vo Thanh Van; Le Hoang Minh

2014-09-02T23:59:59.000Z

280

Towards a Simplified Dynamic Wake Model using POD Analysis  

E-Print Network (OSTI)

We apply the proper orthogonal decomposition (POD) to large eddy simulation data of a wind turbine wake in a turbulent atmospheric boundary layer. The turbine is modeled as an actuator disk. Our analyis mainly focuses on the question whether POD could be a useful tool to develop a simplified dynamic wake model. The extracted POD modes are used to obtain approximate descriptions of the velocity field. To assess the quality of these POD reconstructions, we define simple measures which are believed to be relevant for a sequential turbine in the wake such as the energy flux through a disk in the wake. It is shown that only a few modes are necessary to capture basic dynamical aspects of these measures even though only a small part of the turbulent kinetic energy is restored. Furthermore, we show that the importance of the individual modes depends on the measure chosen. Therefore, the optimal choice of modes for a possible model could in principle depend on the application of interest. We additionally present a pos...

Bastine, David; Wächter, Matthias; Peinke, Joachim

2014-01-01T23:59:59.000Z

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

Large scale molecular dynamics modeling of materials fabrication processes  

SciTech Connect

An atomistic molecular dynamics model of materials fabrication processes is presented. Several material removal processes are shown to be within the domain of this simulation method. Results are presented for orthogonal cutting of copper and silicon and for crack propagation in silica glass. Both copper and silicon show ductile behavior, but the atomistic mechanisms that allow this behavior are significantly different in the two cases. The copper chip remains crystalline while the silicon chip transforms into an amorphous state. The critical stress for crack propagation in silica glass was found to be in reasonable agreement with experiment and a novel stick-slip phenomenon was observed.

Belak, J.; Glosli, J.N.; Boercker, D.B.; Stowers, I.F.

1994-02-01T23:59:59.000Z

282

Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving on a Slope 1 Dynamic Modeling and Adaptive Neural-Fuzzy Control for  

E-Print Network (OSTI)

robots [7]. A robust fuzzy logic controller was devised for a robotic manipulator with uncertainties [8Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving on a Slope 1 Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving

Li, Yangmin

283

MODELLING RADIOIODINE DYNAMICS Modelling the Dynamics of Radioiodine in Dairy Cows  

E-Print Network (OSTI)

Department of Physiology & Environmental Science University of Nottingham Sutton Bonington LE12 5RD UK G for significant fecal excretion of radioiodine. The5 model is used to consider the effect of dietary stable iodine of iodine, in particular I-131, are important components in fallout from2 nuclear accidents

Crout, Neil

284

Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network  

E-Print Network (OSTI)

DS-06-1351 Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network Tomás dynamics of gasoline engines during transient operation. With a collection of input-output data measured;Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network I. INTRODUCTION

Johansen, Tor Arne

285

Optimization For Grade Transitions In Polyethylene Solution Polymerization  

E-Print Network (OSTI)

Optimization For Grade Transitions In Polyethylene Solution Polymerization Jun Shi1, Intan Hamdan2 Engineering Carnegie Mellon University 2The Dow Chemical Company #12;Dynamic Optimization Models Grade Transition for LLDPE · Continuous Stirred-Tank Reactor (CSTR) (represents two actual processes) · Assume

Grossmann, Ignacio E.

286

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

Science Journals Connector (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

287

Designability, thermodynamic stability, and dynamics in protein folding: A lattice model study  

E-Print Network (OSTI)

Designability, thermodynamic stability, and dynamics in protein folding: A lattice model study Re October 1998 In the framework of a lattice-model study of protein folding, we investigate the interplay model. Lattice models have been widely used in the study of protein folding dynamics.2­8 The main

Levine, Alex J.

288

Comparative Studies of Clustering Techniques for Real-Time Dynamic Model Reduction  

E-Print Network (OSTI)

Dynamic model reduction in power systems is necessary for improving computational efficiency. Traditional model reduction using linearized models or offline analysis would not be adequate to capture power system dynamic behaviors, especially the new mix of intermittent generation and intelligent consumption makes the power system more dynamic and non-linear. Real-time dynamic model reduction emerges as an important need. This paper explores the use of clustering techniques to analyze real-time phasor measurements to determine generator groups and representative generators for dynamic model reduction. Two clustering techniques -- graph clustering and evolutionary clustering -- are studied in this paper. Various implementations of these techniques are compared and also compared with a previously developed Singular Value Decomposition (SVD)-based dynamic model reduction approach. Various methods exhibit different levels of accuracy when comparing the reduced model simulation against the original model. But some ...

Hogan, Emilie; Halappanavar, Mahantesh; Huang, Zhenyu; Lin, Guang; Lu, Shuai; Wang, Shaobu

2015-01-01T23:59:59.000Z

289

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

290

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

Science Journals Connector (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

291

Classical spin model of the relaxation dynamics of rare-earth doped permalloy  

Science Journals Connector (OSTI)

In this paper, the ultrafast dynamic behavior of rare-earth doped permalloy is investigated using an atomistic spin model with Langevin dynamics. In line with experimental work, the effective Gilbert damping is calculated from transverse relaxation simulations, which shows that rare-earth doping causes an increase in the damping. Analytic theory suggests that this increase in damping would lead to a decrease in the demagnetization time. However, longitudinal relaxation calculations show an increase with doping concentration instead. The simulations are in a good agreement with previous experimental work of Radu et al. [Radu et al., Phys. Rev. Lett. 102, 117201 (2009)]. The longitudinal relaxation time of the magnetization is shown to be driven by the interaction between the transition metal and the laser-excited conduction electrons, whereas the effective damping is predominantly determined by the slower interaction between the rare-earth elements and the phonon heat bath. We conclude that for complex materials, it is evidently important not to expect a single damping parameter but to consider the energy transfer channel relevant to the technique and time scale of the measurement.

M. O. A. Ellis; T. A. Ostler; R. W. Chantrell

2012-11-19T23:59:59.000Z

292

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

293

Quasi-dynamic model for an organic Rankine cycle  

Science Journals Connector (OSTI)

Abstract When considering solar based thermal energy input to an organic Rankine cycle (ORC), intermittent nature of the heat input does not only adversely affect the power output but also it may prevent ORC to operate under steady state conditions. In order to identify reliability and efficiency of such systems, this paper presents a simplified transient modeling approach for an ORC operating under variable heat input. The approach considers that response of the system to heat input variations is mainly dictated by the evaporator. Consequently, overall system is assembled using dynamic models for the heat exchangers (evaporator and condenser) and static models of the pump and the expander. In addition, pressure drop within heat exchangers is neglected. The model is compared to benchmark numerical and experimental data showing that the underlying assumptions are reasonable for cases where thermal input varies in time. Furthermore, the model is studied on another configuration and mass flow rates of both the working fluid and hot water and hot water’s inlet temperature to the ORC unit are shown to have direct influence on the system’s response.

Musbaudeen O. Bamgbopa; Eray Uzgoren

2013-01-01T23:59:59.000Z

294

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

295

A criterion for the dynamical to kinematical transition of x-ray diffraction on a bent crystal  

SciTech Connect

It is well known that the peak reflectivity of a bent crystal, generally speaking, is smaller than that of a plane crystal, and it goes to zero when the crystal curvature goes to infinity. The reason for this is the transition between dynamical and kinematical diffraction that takes place as the crystal curvature increases. The physical explanation is as follows: the deviation from exact Bragg position along the beam changes so fast that the thickness over which the beam is within a Darwin width becomes too small to reflect the beam. Bent crystals are widely used as focusing elements in X-ray optics, and estimation of whether or not a bent crystal is still perfect enough to provide good reflectivity is of great importance. Currently the Advanced Photon Source (APS) is considering a number of bent crystals as focusing elements for future APS beamlines, including a sagittaly focusing monochromator and bent backscattering analyzer for inelastic X-ray scattering experiments. A criterion is given in answer to the question: To what extent is it possible to bend a crystal without loss of X-ray peak reflectivity? An expression based on the work of Chukhovskii, Gabrielyan and Petrashen, is formulated that applies to anisotropic cubic crystal and that can be used not only for conventional asymmetric Bragg diffraction, but also for inclined crystal diffraction. The following special cases are treated as examples: isotropic crystal, standard symmetrical Bragg diffraction, extremely asymmetric diffraction, and backscattering with Bragg angles near 90{degree}. In addition, an asymptotic behavior for high energies is detailed.

Kushnir, V.I.; Macrander, A.T.

1993-09-01T23:59:59.000Z

296

Ecosystem dynamics at six contrasting sites: a generic modelling study  

Science Journals Connector (OSTI)

A pelagic marine ecosystem simulation model ERSEM-2004, developed from the European Regional Seas Ecosystem Model (ERSEM II), is presented along with a parameter set applicable to six highly contrasting sites, ranging from a temperate mixed shelf station to a permanently stratified tropical deep-ocean station. The physical characteristics are simulated by direct coupling to a 1D vertically resolved turbulence model, parameterised for each site. A mathematical description of the pelagic ecosystem model is presented. Additions to ERSEM II's well resolved community and decoupling of gross production and ambient nutrient concentration include variable carbon to chlorophyll ratios, coupling of bacterial production to nutrient availability, improved resolution of the organic particulate and dissolved fractions and developments to the mesozooplankton description. Comparison of seasonally depth resolved and integrated properties illustrates that the model produces a wide range of community dynamics and structures that can be plausibly related to variations in mixing, temperature, irradiance and nutrient supply. The spatial–temporal variability in key environmental indicators only partially correlates with the spatial–temporal variability in community structure (?0.75) between spatial–temporal variability in community structure (biomass) and function (production). ERSEM-2004 is shown to be a robust model that is capable of representing a range of systems commonly described in the marine system. Consequently, the model is proposed as a potential basis for an ecosystem-based management tool that may, with appropriate physical representation, be applied over large geographic and temporal scales with utility to both heuristic and predictive studies of the marine lower trophic levels.

J.C. Blackford; J.I. Allen; F.J. Gilbert

2004-01-01T23:59:59.000Z

297

Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics  

SciTech Connect

Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO{sub 2} concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO{sub 2} concentration, temperature, and radiation when evaluated against published data of V{sub c,max} (maximum carboxylation rate) and J{sub max} (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO{sub 2} concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation feedbacks to climate in Earth system models.

Xu, Chonggang [Los Alamos National Laboratory (LANL); Fisher, Rosie [National Center for Atmospheric Research (NCAR); Wullschleger, Stan D [ORNL; Wilson, Cathy [Los Alamos National Laboratory (LANL); Cai, Michael [Los Alamos National Laboratory (LANL); McDowell, Nathan [Los Alamos National Laboratory (LANL)

2012-01-01T23:59:59.000Z

298

A two-phase flow model of sediment transport: transition from bedload to suspended load  

E-Print Network (OSTI)

The transport of dense particles by a turbulent flow depends on two dimensionless numbers. Depending on the ratio of the shear velocity of the flow to the settling velocity of the particles (or the Rouse number), sediment transport takes place in a thin layer localized at the surface of the sediment bed (bedload) or over the whole water depth (suspended load). Moreover, depending on the sedimentation Reynolds number, the bedload layer is embedded in the viscous sublayer or is larger. We propose here a two-phase flow model able to describe both viscous and turbulent shear flows. Particle migration is described as resulting from normal stresses, but is limited by turbulent mixing and shear-induced diffusion of particles. Using this framework, we theoretically investigate the transition between bedload and suspended load.

Filippo Chiodi; Philippe Claudin; Bruno Andreotti

2014-09-02T23:59:59.000Z

299

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

300

Entanglement spectrum and quantum phase transitions in one-dimensional XXZ model with uniaxial single-ion anisotropy  

Science Journals Connector (OSTI)

Abstract Quantum phase transitions (QPTs) in one-dimensional S = 1 XXZ model with uniaxial single-ion anisotropy are investigated. Bipartite entanglement, entanglement spectrum, and Schmidt gap are found to be capable of describing all the QPTs, even the infinite-order Berezinskii–Kosterlitz–Thouless (BKT) transition. According to the singular behavior of the second-order derivative of ground-state energy, the QPT between XY2 and antiferromagnetic phases is a second-order but not a BKT transition. Energy level crossing, accompanied with discontinuous entanglement entropy and entanglement spectrum, is observed at the transition point between the large-D and antiferromagnetic phases, therefore it should be a first-order QPT. In addition, doubly degenerate entanglement spectrum in the Haldane phase is observed.

Guang-Hua Liu; Wei Li; Wen-Long You; Gang Su; Guang-Shan Tian

2014-01-01T23:59:59.000Z

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.
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to obtain the most current and comprehensive results.


301

Shell model study of $^{40}$Ca muon capture and the $(0^+, 0)$$\\to$$(0^-, 2626)$ axial charge transition  

E-Print Network (OSTI)

We report results from shell model studies of muon capture on $^{40}$Ca to low-lying levels of $^{40}$K. We discuss the comparison between calculated capture rates, measured capture rates and analogous transitions in ($e$,$e^{\\prime}$) scattering in terms of the particle-hole structure of the $^{40}$Ca-$^{40}$K nuclei. We highlight the $^{40}$Ca$(0^+, 0)$$\\to$$^{40}$K$(0^-, 2626)$ axial charge transition and its sensitivity to the induced pseudoscalar coupling $g_p$ of the proton's weak interaction. In addition, we address the hindrance of unique first-forbidden transitions due to particle-hole interactions and the emergence of allowed Gamow-Teller transitions due to ground state correlations. Lastly, we examine the longitudinal alignment of $^{40}$K recoils following muon capture, and discuss this possibility for independently determining the induced coupling $g_p$.

T. P. Gorringe

2006-06-14T23:59:59.000Z

302

Object-oriented modelling and simulation for the ALFRED dynamics  

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Abstract In this paper, a control-oriented modelling and simulation tool for the study of the Advanced Lead-cooled Fast Reactor European Demonstrator (ALFRED) plant dynamics is presented. It has been developed in order to perform design-basis transient analyses aimed at providing essential feedbacks for the system design finalization. The simulator has been meant to be modular, open and efficient. In this perspective, an object-oriented modelling approach has been adopted, by employing the reliable, tested and well-documented Modelica language. Simulation of core behaviour is based on point kinetics for neutronics and one-dimensional heat transfer models for thermal-hydraulics, coherently with ALFRED specifications. An effort has been spent to model the bayonet-tube Steam Generator (SG) foreseen to be installed within the reactor vessel. The primary loop model has been built by connecting the above-mentioned components (taking into account suitable time delays) and by incorporating the cold pool, which has revealed to be fundamental for an accurate definition of the time constants characteristic of the system because of its large thermal inertia. The description of the overall plant has been finalized by connecting standard turbine, condenser and other components of the balance of plant. Afterwards, the reactor responses to three typical transient initiators have been simulated (i.e., reduction of feedwater mass flow rate, variation of the turbine admission valve coefficient and transient of overpower). Simulation outcomes confirm the strong coupling between core and SG, besides showing the characteristic time constants of the various component responses. Results of the present study constitute a starting point in the definition of plant control strategies, laying the basis for investigation and development of a model-based control-system design.

Roberto Ponciroli; Andrea Bigoni; Antonio Cammi; Stefano Lorenzi; Lelio Luzzi

2014-01-01T23:59:59.000Z

303

Critical points and transitions in an electric power transmission model for cascading failure blackouts  

Science Journals Connector (OSTI)

Cascading failures in large-scale electric power transmission systems are an important cause of blackouts. Analysis of North American blackout data has revealed power law (algebraic) tails in the blackout size probability distribution which suggests a dynamical origin. With this observation as motivation we examine cascading failure in a simplified transmission system model as load power demand is increased. The model represents generators loads the transmission line network and the operating limits on these components. Two types of critical points are identified and are characterized by transmission line flow limits and generator capability limits respectively. Results are obtained for tree networks of a regular form and a more realistic 118-node network. It is found that operation near critical points can produce power law tails in the blackout size probability distribution similar to those observed. The complex nature of the solution space due to the interaction of the two critical points is examined.

B. A. Carreras; V. E. Lynch; I. Dobson; D. E. Newman

2002-01-01T23:59:59.000Z

304

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

Paris-Sud XI, Université de

305

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances  

E-Print Network (OSTI)

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances C. Canudas we derive a new dynamic friction force model for the longitudinal road/tire interaction for wheeled-point friction problems, called the LuGre model [1]. By assuming a con- tact patch between the tire

Tsiotras, Panagiotis

306

Lateral Dynamics Reconstruction for Sharp'71 Motorcycle Model with P2I Observer  

E-Print Network (OSTI)

Lateral Dynamics Reconstruction for Sharp'71 Motorcycle Model with P2I Observer Chabane Chenane (motorcycle, scooter, etc.). For that purpose, the well-known motorcycle model developed by Sharp in 1971 is used. This model characterizes the lateral dynamics of a motorcycle [16]. The roll angle

Paris-Sud XI, Université de

307

Eddy-Mediated Regime Transitions in the Seasonal Cycle of a Hadley Circulation and Implications for Monsoon Dynamics  

E-Print Network (OSTI)

Eddy-Mediated Regime Transitions in the Seasonal Cycle of a Hadley Circulation and Implications symmetric boundary conditions, the Hadley cells undergo transitions between two regimes distinguishable. The center of the summer and equinox Hadley cell lies in a latitude zone of upper-level westerlies

Bordoni, Simona

308

Genome-Wide Dynamic Transcriptional Profiling of the Light-to-Dark Transition in Synechocystis sp. Strain PCC 6803  

Science Journals Connector (OSTI)

...two cycles of light/dark conditions, during which...throughout the light/dark transition, (ii) 25...photosynthesis and primary energy generation are discussed...throughout the light/dark transition and to determine...enabled researchers to survey the expression levels...

Ryan T. Gill; Eva Katsoulakis; William Schmitt; Gaspar Taroncher-Oldenburg; Jatin Misra; Gregory Stephanopoulos

2002-07-01T23:59:59.000Z

309

O-regime dynamics and modeling in Tore Supra  

SciTech Connect

The regime of nonlinear temperature oscillations (O-regime), characteristic of noninductive discharges on Tore Supra [Equipe Tore Supra, Proceedings of the 12th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Nice, France, 1988 (International Atomic Energy Agency, Vienna, 1989), Vol. 1, p. 9], is investigated in its triggering and suppressing mechanism. This regime can be described by two nonlinearly coupled equations for the current density j(r) and the electron temperature T{sub e}(r) where the equation coefficients are functions of j and T{sub e} themselves. Both the integrated modeling code CRONOS[V. Basiuk et al., Nucl. Fusion 43, 822 (2003)] and a two-patch predator-prey system with diffusion and noise have been used and results have been compared to the experimental observations of the O-regime. A database of discharges is analyzed which features monotonic, flat, and reversed safety factor (q) profiles in order to characterize the action of external actuators on the regime dynamics with the widest generality. Electron cyclotron current drive and neutral beam injections have been used in order to induce localized perturbations in the total current profile j(r) as well as to change the plasma confinement conditions in the central region. Magnetic shear perturbations and modifications of the heat transport turn out to be the central parameters governing the dynamics of the O-regime.

Turco, F.; Giruzzi, G.; Imbeaux, F.; Udintsev, V. S.; Artaud, J. F.; Barana, O.; Dumont, R.; Mazon, D.; Segui, J.-L. [CEA-IRFM, 13108 St. Paul-les-Durance (France)

2009-06-15T23:59:59.000Z

310

CB17: Inferring the dynamical history of a prestellar core with chemo-dynamical models  

E-Print Network (OSTI)

We present a detailed theoretical study of the isolated Bok globule CB17 (L1389) based on spectral maps of CS, HCO$^+$, C$^{18}$O, C$^{34}$S, and H$^{13}$CO$^+$ lines. A phenomenological model of prestellar core evolution, a time-dependent chemical model, and a radiative transfer simulation for molecular lines are combined to reconstruct the chemical and kinematical structure of this core. We developed a general criterion that allows to quantify the difference between observed and simulated spectral maps. By minimizing this difference, we find that very high and very low values of the effective sticking probability $S$ are not appropriate for the studied prestellar core. The most probable $S$ value for CB17 is 0.3--0.5. The spatial distribution of the intensities and self-absorption features of optically thick lines is indicative of UV irradiation of the core. By fitting simultaneously optically thin and optically thick transitions, we isolate the model that reproduces all the available spectral maps to a reasonable accuracy. The line asymmetry pattern in CB17 is reproduced by a combination of infall, rotation, and turbulent motions with velocities $\\sim0.05$ km s$^{-1}$, $\\sim0.1$ km s$^{-1}$, and $\\sim0.1$ km s$^{-1}$, respectively. These parameters corresponds to energy ratios $E_{\\rm rot}/E_{\\rm grav}\\approx0.03$, $E_{\\rm therm}/E_{\\rm grav}\\approx0.8$, and $E_{\\rm turb}/E_{\\rm grav}\\approx0.05$ (the rotation parameters are determined for $i=90^\\circ$). The chemical age of the core is about 2 Myrs. In particular, this is indicated by the central depletion of CO, CS, and HCO$^+$. Based on the angular momentum value, we argue that the core is going to fragment, i.e., to form a binary (multiple) star. (abridged)

Ya. Pavlyuchenkov; D. Wiebe; R. Launhardt; Th. Henning

2006-03-22T23:59:59.000Z

311

The Dynamics of Deterministic Chaos in Numerical Weather Prediction Models  

E-Print Network (OSTI)

Atmospheric weather systems are coherent structures consisting of discrete cloud cells forming patterns of rows/streets, mesoscale clusters and spiral bands which maintain their identity for the duration of their appreciable life times in the turbulent shear flow of the planetary Atmospheric Boundary Layer. The existence of coherent structures (seemingly systematic motion) in turbulent flows has been well established during the last 20 years of research in turbulence. Numerical weather prediction models based on the inherently non-linear Navier-Stokes equations do not give realistic forecasts because of the following inherent limitations: (1) the non-linear governing equations for atmospheric flows do not have exact analytic solutions and being sensitive to initial conditions give chaotic solutions characteristic of deterministic chaos (2) the governing equations do not incorporate the dynamical interactions and co-existence of the complete spectrum of turbulent fluctuations which form an integral part of the large coherent weather systems (3) limitations of available computer capacity necessitates severe truncation of the governing equations, thereby generating errors of approximations (4) the computer precision related roundoff errors magnify the earlier mentioned uncertainties exponentially with time and the model predictions become unrealistic. The accurate modelling of weather phenomena therefore requires alternative concepts and computational techniques. In this paper a universal theory of deterministic chaos applicable to the formation of coherent weather structures in the ABL is presented.

A. Mary Selvam

2003-10-07T23:59:59.000Z

312

Emerging disease dynamics in a model coupling within-host and ...  

E-Print Network (OSTI)

Aug 2, 2014 ... Immunological models consider the within-host dynamics independent of the interactions between hosts (e.g., De Leenheer and Smith, 2003;.

Xiuli Cen

2014-08-27T23:59:59.000Z

313

Estimation of Parameterized Spatio-Temporal Dynamic Models Ke Xu and Christopher K. Wikle  

E-Print Network (OSTI)

Estimation of Parameterized Spatio-Temporal Dynamic Models Ke Xu and Christopher K. Wikle: Christopher K. Wikle, Department of Statistics, University of Missouri, 146 Math Science Building, Columbia

314

Dynamic Modeling of Cell Migration and Spreading Behaviors on Fibronectin Coated Planar Substrates and Micropatterned Geometries  

E-Print Network (OSTI)

An integrative cell migration model incorporating focal adhesion (FA) dynamics, cytoskeleton and nucleus remodeling, actin motor activity, and lamellipodia protrusion is developed for predicting cell spreading and migration ...

Kim, Min-Cheol

315

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

SciTech Connect

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

316

Uncertainties in nuclear transition matrix elements for neutrinoless ?? decay within the projected-Hartree-Fock-Bogoliubov model  

Science Journals Connector (OSTI)

The nuclear transition matrix elements M(0?) for the neutrinoless ?? decay of Zr94,96, Mo98,100, Ru104, Pd110, Te128,130, and Nd150 isotopes in the case of 0+?0+ transition are calculated using the projected-Hartree-Fock-Bogoliubov wave functions, which are eigenvectors of four different parametrizations of a Hamiltonian with pairing plus multipolar effective two-body interaction. Employing two (three) different parametrizations of Jastrow-type short-range correlations, a set of eight (twelve) different nuclear transition matrix elements M(0?) is built for each decay, whose averages in conjunction with their standard deviations provide an estimate of the model’s uncertainties.

P. K. Rath, R. Chandra, K. Chaturvedi, P. K. Raina, and J. G. Hirsch

2010-12-17T23:59:59.000Z

317

Escape model for Galactic cosmic rays and an early extragalactic transition  

E-Print Network (OSTI)

We show that the cosmic ray (CR) knee can be entirely explained by energy-dependent CR leakage from the Milky Way, with an excellent fit to all existing data. We test this hypothesis calculating the trajectories of individual CRs in the Galactic magnetic field. We find that the CR escape time $\\tau_{\\rm esc}(E)$ exhibits a knee-like structure around $E/Z={\\rm few}\\times 10^{15}$ eV for small coherence lengths and strengths of the turbulent magnetic field. The resulting intensities for different groups of nuclei are consistent with the ones determined by KASCADE and KASCADE-Grande, using simple power-laws as injection spectra. The transition from Galactic to extragalactic CRs is terminated at $\\approx 2\\times 10^{18}$ eV, while extragalactic CRs contribute sizeable to the subdominant proton flux already for $\\gtrsim 2\\times 10^{16}$ eV. The natural source of extragalactic CRs in the intermediate energy region up to the ankle are in this model normal and starburst galaxies. The escape model provides a good fit ...

Giacinti, G; Semikoz, D V

2015-01-01T23:59:59.000Z

318

Crosstalk and transitions between multiple spatial maps in an attractor neural network model of the hippocampus: Collective motion of the activity  

Science Journals Connector (OSTI)

The dynamics of a neural model for hippocampal place cells storing spatial maps is studied. In the absence of external input, depending on the number of cells and on the values of control parameters (number of environments stored, level of neural noise, average level of activity, connectivity of place cells), a “clump” of spatially localized activity can diffuse or remains pinned due to crosstalk between the environments. In the single-environment case, the macroscopic coefficient of diffusion of the clump and its effective mobility are calculated analytically from first principles and corroborated by numerical simulations. In the multienvironment case the heights and the widths of the pinning barriers are analytically characterized with the replica method; diffusion within one map is then in competition with transitions between different maps. Possible mechanisms enhancing mobility are proposed and tested.

R. Monasson and S. Rosay

2014-03-11T23:59:59.000Z

319

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons with observations during the 2001  

E-Print Network (OSTI)

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons several hundred kilometers offshore where shelf flows interact with the northern California Current is realistic representation of coastal jet separation and eddy formation offshore of Cape Blanco. Three

Kurapov, Alexander

320

Simulation of systems with dynamically varying model structure  

Science Journals Connector (OSTI)

Hybrid systems are dynamical systems composed of components with discrete and continuous behavior. Some systems change their structure during simulation, or their components behavior is essentially changing. This ''structural dynamics'' can be described ... Keywords: Discrete-continuous simulation, Hybrid systems, Modelica, Structural dynamics, VHDL-AMS

Peter Schwarz

2008-12-01T23:59:59.000Z

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.


321

Pion photoproduction in a dynamical coupled-channels model  

E-Print Network (OSTI)

The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, and Nakayama [Phys. Rev. C 83, 065502 (2011)]. The hadronic final-state interaction is provided by the Juelich pi-N model, which includes the channels pi-N and eta-N comprising stable hadrons as well as the effective pi-pi-N channels pi-Delta, sigma-N, and rho-N. This hadronic model has been quite successful in describing pi-N to pi-N scattering for center-of-mass energies up to 1.9 GeV. By construction, the full pion photoproduction current satisfies the generalized Ward-Takahashi identity and thus is gauge invariant as a matter of course. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions gamma p to pi+ n, gamma p to pi0 p, gamma n to pi- p and gamma n to pi0 n are in good agreement with the experimental data.

Huang, F; Haberzettl, H; Haidenbauer, J; Hanhart, C; Krewald, S; ner, U -G Meiß; Nakayama, K

2011-01-01T23:59:59.000Z

322

Pion photoproduction in a dynamical coupled-channels model  

E-Print Network (OSTI)

The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, and Nakayama [Phys. Rev. C 83, 065502 (2011)]. The hadronic final-state interaction is provided by the Juelich pi-N model, which includes the channels pi-N and eta-N comprising stable hadrons as well as the effective pi-pi-N channels pi-Delta, sigma-N, and rho-N. This hadronic model has been quite successful in describing pi-N to pi-N scattering for center-of-mass energies up to 1.9 GeV. By construction, the full pion photoproduction current satisfies the generalized Ward-Takahashi identity and thus is gauge invariant as a matter of course. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions gamma p to pi+ n, gamma p to pi0 p, gamma n to pi- p and gamma n to pi0 n are in good agreement with the experimental data.

F. Huang; M. Döring; H. Haberzettl; J. Haidenbauer; C. Hanhart; S. Krewald; U. -G. Meiß ner; K. Nakayama

2011-10-17T23:59:59.000Z

323

Substrate-induced microstructure effects on the dynamics of the photo-induced Metal-insulator transition in VO$_2$ thin films  

E-Print Network (OSTI)

We investigate the differences in the dynamics of the ultrafast photo-induced metal-insulator transition (MIT) of two VO$_2$ thin films deposited on different substrates, TiO$_2$ and Al$_2$O$_3$, and in particular the temperature dependence of the threshold laser fluence values required to induce various MIT stages in a wide range of sample temperatures (150 K - 320 K). We identified that, although the general pattern of MIT evolution was similar for the two samples, there were several differences. Most notably, the threshold values of laser fluence required to reach the transition to a fully metallic phase in the VO$_2$ film on the TiO$_2$ substrate were nearly constant in the range of temperatures considered, whereas the VO$_2$/Al$_2$O$_3$ sample showed clear temperature dependence. Our analysis qualitatively connects such behavior to the structural differences in the two VO$_2$ films.

Radue, E; Kittiwatanakul, S; Lu, J; Wolf, S A; Rossi, E; Lukaszew, R A; Novikova, I

2014-01-01T23:59:59.000Z

324

Ultrafast Structural Dynamics in Combustion Relevant Model Systems  

SciTech Connect

The research project explored the time resolved structural dynamics of important model reaction system using an array of novel methods that were developed specifically for this purpose. They include time resolved electron diffraction, time resolved relativistic electron diffraction, and time resolved Rydberg fingerprint spectroscopy. Toward the end of the funding period, we also developed time-resolved x-ray diffraction, which uses ultrafast x-ray pulses at LCLS. Those experiments are just now blossoming, as the funding period expired. In the following, the time resolved Rydberg Fingerprint Spectroscopy is discussed in some detail, as it has been a very productive method. The binding energy of an electron in a Rydberg state, that is, the energy difference between the Rydberg level and the ground state of the molecular ion, has been found to be a uniquely powerful tool to characterize the molecular structure. To rationalize the structure sensitivity we invoke a picture from electron diffraction: when it passes the molecular ion core, the Rydberg electron experiences a phase shift compared to an electron in a hydrogen atom. This phase shift requires an adjustment of the binding energy of the electron, which is measurable. As in electron diffraction, the phase shift depends on the molecular, geometrical structure, so that a measurement of the electron binding energy can be interpreted as a measurement of the molecule’s structure. Building on this insight, we have developed a structurally sensitive spectroscopy: the molecule is first elevated to the Rydberg state, and the binding energy is then measured using photoelectron spectroscopy. The molecule’s structure is read out as the binding energy spectrum. Since the photoionization can be done with ultrafast laser pulses, the technique is inherently capable of a time resolution in the femtosecond regime. For the purpose of identifying the structures of molecules during chemical reactions, and for the analysis of molecular species in the hot environments of combustion processes, there are several features that make the Rydberg ionization spectroscopy uniquely useful. First, the Rydberg electron’s orbit is quite large and covers the entire molecule for most molecular structures of combustion interest. Secondly, the ionization does not change vibrational quantum numbers, so that even complicated and large molecules can be observed with fairly well resolved spectra. In fact, the spectroscopy is blind to vibrational excitation of the molecule. This has the interesting consequence for the study of chemical dynamics, where the molecules are invariably very energetic, that the molecular structures are observed unobstructed by the vibrational congestion that dominates other spectroscopies. This implies also that, as a tool to probe the time-dependent structural dynamics of chemically interesting molecules, Rydberg spectroscopy may well be better suited than electron or x-ray diffraction. With recent progress in calculating Rydberg binding energy spectra, we are approaching the point where the method can be evolved into a structure determination method. To implement the Rydberg ionization spectroscopy we use a molecular beam based, time-resolved pump-probe multi-photon ionization/photoelectron scheme in which a first laser pulse excites the molecule to a Rydberg state, and a probe pulse ionizes the molecule. A time-of-flight detector measures the kinetic energy spectrum of the photoelectrons. The photoelectron spectrum directly provides the binding energy of the electron, and thereby reveals the molecule’s time-dependent structural fingerprint. Only the duration of the laser pulses limits the time resolution. With a new laser system, we have now reached time resolutions better than 100 fs, although very deep UV wavelengths (down to 190 nm) have slightly longer instrument functions. The structural dynamics of molecules in Rydberg-excited states is obtained by delaying the probe ionization photon from the pump photon; the structural dynamics of molecules in their ground state or e

Weber, Peter M. [Brown University

2014-03-31T23:59:59.000Z

325

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

326

A comparison of Bayesian versus deterministic formulation for dynamic data integration into reservoir models  

E-Print Network (OSTI)

Into Reservoir Models. (Decmnber 200 I) Danny LL Rojas Paico, B. S. , Universidad Nacional de Ingenieria, Peru Chair of Advisory Committee: Dr. Akhil Datta-Gupta The integration of dynamic data into reservoir models is known as automatic history matching...

Rojas Paico, Danny H.

2001-01-01T23:59:59.000Z

327

Evolutionary Processes in Economics: Multi-agent Model of Macrogenerations Dynamics  

E-Print Network (OSTI)

Evolutionary Processes in Economics: Multi-agent Model of Macrogenerations Dynamics Kateryna macroeconomic growth as an evolutionary process. Keywords. Economic growth, evolutionary theory, multi]. Our study models the economic growth as an evolutionary process, where the term `macrogeneration

López-Sánchez, Maite

328

STOCHASTIC COMPUTATIONAL DYNAMICAL MODEL OF UNCERTAIN STRUCTURE COUPLED WITH AN INSULATION LAYER  

E-Print Network (OSTI)

STOCHASTIC COMPUTATIONAL DYNAMICAL MODEL OF UNCERTAIN STRUCTURE COUPLED WITH AN INSULATION LAYER the effect of insulation layers in complex dynamical systems for low- and medium-frequency ranges such as car booming noise analysis, one introduces a sim- plified stochastic model of insulation layers based

Boyer, Edmond

329

A stochastic agent-based model of pathogen propagation in dynamic multi-relational social networks  

Science Journals Connector (OSTI)

We describe a general framework for modeling and stochastic simulation of epidemics in realistic dynamic social networks, which incorporates heterogeneity in the types of individuals, types of interconnecting risk-bearing relationships, and types of ... Keywords: Agent-based systems, Social Factors for HIV Risk, modeling and simulation environments, network-based simulation, risk network, system dynamics

Bilal Khan, Kirk Dombrowski, Mohamed Saad

2014-04-01T23:59:59.000Z

330

A DYNAMICAL MODEL OF TERRORISM FIRDAUS UDWADIA, GEORGE LEITMANN, AND LUCA LAMBERTINI  

E-Print Network (OSTI)

A DYNAMICAL MODEL OF TERRORISM FIRDAUS UDWADIA, GEORGE LEITMANN, AND LUCA LAMBERTINI Received 25 April 2006; Accepted 10 May 2006 This paper develops a dynamical model of terrorism. We consider the susceptibles to become pacifists. The paper proposes a new paradigm for studying terrorism, and looks

Udwadia, Firdaus E.

331

The living cell as a multi-agent organisation: a compositional organisation model of intracellular dynamics  

Science Journals Connector (OSTI)

Within the areas of Computational Organisation Theory and Artificial Intelligence, techniques have been developed to simulate and analyse dynamics within organisations in society. Usually these modelling techniques are applied to factories and to the ... Keywords: dynamics, intracellular, modular control analysis, organisational modeling, regulation and control

C. M. Jonker; J. L. Snoep; J. Treur; H. V. Westerhoff; W. C. A. Wijngaards

2010-01-01T23:59:59.000Z

332

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results  

E-Print Network (OSTI)

Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results C. Canudas dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is val- idated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps

Tsiotras, Panagiotis

333

Development of a Dynamic Model of a Small High-Speed Autonomous Underwater Vehicle  

E-Print Network (OSTI)

Development of a Dynamic Model of a Small High-Speed Autonomous Underwater Vehicle Haider N. Arafat-- A dynamic model is developed for a small, high- speed autonomous underwater vehicle. The vehicle has manner: 1) Wind angle and angle : From u = V cos , v = V sin sin , and w = V sin cos , we have tan

Virginia Tech

334

Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model  

E-Print Network (OSTI)

Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model for the filtering of noisy ECG signals. The method is based on a modified nonlinear dynamic model, previously introduced for the generation of synthetic ECG signals. An automatic parameter selection method has also been

Paris-Sud XI, Université de

335

ECG Denoising Using a Dynamical Model and a Marginalized Particle Filter  

E-Print Network (OSTI)

ECG Denoising Using a Dynamical Model and a Marginalized Particle Filter Chao Lin1,3, M of robust ECG denoising tech- niques is important for automatic diagnoses of cardiac diseases. Based on a previously suggested nonlinear dynamic model for the generation of realistic synthetic ECG, we introduce

Tourneret, Jean-Yves

336

Modeling the Cost Structure of Public Transit Firms: Scale Economies and Functional Form (#09-3435) Michael Iacono, University of Minnesota  

E-Print Network (OSTI)

Modeling the Cost Structure of Public Transit Firms: Scale Economies and Functional Form (#09-3435) Michael Iacono, University of Minnesota Abstract This study analyzes the cost structure of a set of medium in the production of transit services. Short and long-run costs are modeled using two of the more commonly

Levinson, David M.

337

Filling and wetting transitions on sinusoidal substrates: a mean-field study of the Landau-Ginzburg model  

E-Print Network (OSTI)

We study the interfacial phenomenology of a fluid in contact with a microstructured substrate within the mean-field approximation. The sculpted substrate is a one-dimensional array of infinitely long grooves of sinusoidal section of periodicity length L and amplitude A. The system is modelled using the Landau-Ginzburg functional, with fluid-substrate couplings which correspond to either first-order or critical wetting for a flat substrate. We investigate the effect of the roughness of the substrate in the interfacial phenomenology, paying special attention to filling and wetting phenomena, and compare the results with the predictions of the macroscopic and interfacial Hamiltonian theories. At bulk coexistence, for values of L much larger than the bulk correlation, we observe first-order filling transitions between dry and partially filled interfacial states, which extend off-coexistence, ending at a critical point; and wetting transitions between partially filled and completely wet interfacial states with the same order as for the flat substrate (if first-order, wetting extends off-coexistence in a prewetting line). On the other hand, if the groove height is of order of the correlation length, only wetting transitions between dry and complete wet states are observed. However, their characteristics depend on the order of the wetting transition for the flat substrate. So, if it is first-order, the wetting transition temperature for the rough substrate is reduced with respect to the wetting transition temperature for a flat substrate, and coincides with the Wenzel law prediction for very shallow substrates. On the contrary, if the flat substrate wetting transition is continuous, the roughness does not change the wetting temperature.

Alvaro Rodriguez-Rivas; Jose Antonio Galvan Moreno; Jose M. Romero-Enrique

2014-08-05T23:59:59.000Z

338

Molecular dynamics beyonds the limits: massive scaling on 72 racks of a BlueGene/P and supercooled glass transition of a 1 billion particles system  

E-Print Network (OSTI)

We report scaling results on the world's largest supercomputer of our recently developed Billions-Body Molecular Dynamics (BBMD) package, which was especially designed for massively parallel simulations of the atomic dynamics in structural glasses and amorphous materials. The code was able to scale up to 72 racks of an IBM BlueGene/P, with a measured 89% efficiency for a system with 100 billion particles. The code speed, with less than 0.14 seconds per iteration in the case of 1 billion particles, paves the way to the study of billion-body structural glasses with a resolution increase of two orders of magnitude with respect to the largest simulation ever reported. We demonstrate the effectiveness of our code by studying the liquid-glass transition of an exceptionally large system made by a binary mixture of 1 billion particles.

Allsopp, N; Fratalocchi, A

2011-01-01T23:59:59.000Z

339

Volatility forecasting with smooth transition exponential smoothing  

Science Journals Connector (OSTI)

Adaptive exponential smoothing methods allow smoothing parameters to change over time, in order to adapt to changes in the characteristics of the time series. This paper presents a new adaptive method for predicting the volatility in financial returns. It enables the smoothing parameter to vary as a logistic function of user-specified variables. The approach is analogous to that used to model time-varying parameters in smooth transition generalised autoregressive conditional heteroskedastic (GARCH) models. These non-linear models allow the dynamics of the conditional variance model to be influenced by the sign and size of past shocks. These factors can also be used as transition variables in the new smooth transition exponential smoothing (STES) approach. Parameters are estimated for the method by minimising the sum of squared deviations between realised and forecast volatility. Using stock index data, the new method gave encouraging results when compared to fixed parameter exponential smoothing and a variety of GARCH models.

James W. Taylor

2004-01-01T23:59:59.000Z

340

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

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

Liquid-liquid phase transition model incorporating evidence for ferroelectric state near the lambda-point anomaly in supercooled water  

E-Print Network (OSTI)

We propose a unified model combining the first-order liquid-liquid and the second-order ferroelectric phase transitions models and explaining various features of the $\\lambda$-point of liquid water within a single theoretical framework. It becomes clear within the proposed model that not only does the long-range dipole-dipole interaction of water molecules yield a large value of dielectric constant $\\epsilon$ at room temperatures, our analysis shows that the large dipole moment of the water molecules also leads to a ferroelectric phase transition at a temperature close to the lambda-point. Our more refined model suggests that the phase transition occurs only in the low density component of the liquid and is the origin of the singularity of the dielectric constant recently observed in experiments with supercooled liquid water at temperature T~233K. This combined model agrees well with nearly every available set of experiments and explains most of the well-known and even recently obtained results of MD simulations.

Peter O. Fedichev; Leonid I. Menshikov

2012-01-30T23:59:59.000Z

342

Entanglement and spin squeezing in non-Hermitian phase transitions  

E-Print Network (OSTI)

We show that non-Hermitian dynamics generate substantial entanglement in many-body systems. We consider the non-Hermitian Lipkin-Meshkov-Glick model and show that the non-Hermitian phase transition occurs with maximum multi-particle entanglement: there is full N-particle entanglement at the transition, in contrast to the Hermitian case. The non-Hermitian model also exhibits more spin squeezing than the Hermitian model, showing that non-Hermitian dynamics are useful for quantum metrology. Experimental implementations with cavity-QED and trapped ions are discussed.

Tony E. Lee; Florentin Reiter; Nimrod Moiseyev

2014-09-24T23:59:59.000Z

343

Order, chaos and nuclear dynamics: An introduction  

SciTech Connect

This is an introductory lecture illustrating by simple examples the anticipated effect on collective nuclear dynamics of a transition from order to chaos in the motions of nucleons inside an idealized nucleus. The destruction of order is paralleled by a transition from a rubber-like to a honey-like behaviour of the independent-particle nuclear model. 10 refs., 6 figs.

Swiatecki, W.J.

1990-08-01T23:59:59.000Z

344

Dynamic models towards operator and engineer training: Virtual environment  

Science Journals Connector (OSTI)

The simulation of chemical processes is an important tool for solving problems in Computer Aided Process Engineering (CAPE) and the use of commercial simulators is essential for this task. In this work, the intention is to create a virtual environment for industrial process and data representations for operator and engineer training. The applications focus on the separation process dynamic and control. The first case is an azeotropic distillation process. It was used an industrial plant data to illustrate the importance of reliable thermodynamic data to the process simulation. The system studied is the ethanol/water separation using cyclohexane as mass separating agent. As the second case, it was used a refinery data to simulate the debutanizer column of a fluid catalytic cracking unit in order to make this complex problem understandable, well represented and easily reproducible in a simulation framework. In this case, optimization, regulatory control, PID tuning and model predictive control were considered. The energy consumption was minimized using the SQP method. Simulations were performed using HYSYS. Plant process simulator.

Claudia J.G. Vasconcelos; Rubens Maciel Filho; Renato Spandri; Maria R. Wolf-Maciel

2005-01-01T23:59:59.000Z

345

Adaptation costs for sustainable development and ecological transitions: a presentation of the structural model M3ED with reference to French energy?economy?carbon dioxide emission prospects*  

Science Journals Connector (OSTI)

The aim of this paper is to assess the adaptation costs associated with the transition to a sustainable development path, taking the example of carbon dioxide emissions in the French economy. The model used is based on systems dynamics modelling and energy input-output analysis. This type of approach has the interesting property of precisely defining the nature of interactions between the different economic sectors, and between the economic sectors and the environment. This provides a framework within which to test different types of economic, technology and environment policy. In effect, according to our interests, it is necessary to measure problems of resources allocation or sequential choices between different alternatives why and how a particular solution comes to be selected from a multiplicity of alternatives. First, we characterise the methodological and conceptual specification of the model. Secondly, we locate specific properties of the model linked with both ecological sustainability and economic feasability constraints. Thirdly, a sensitivity test is applied concerning different control policy scenarios for the case of carbon dioxide emissions in the French economy.

Patrick Schembri

1999-01-01T23:59:59.000Z

346

Modeling Thermodynamics and Dynamics of MixtureModeling Thermodynamics and Dynamics of Mixture Adsorption in Porous MaterialsAdsorption in Porous Materials  

E-Print Network (OSTI)

models to describe adsorption dynamics · Apply to case of Enhanced Coalbed Methane Extraction ­ Trillions of cubic meters of methane and carbon dioxide can be extracted and stored in unusable coal seams Models temperature, adsorption increases with pressure. Carbon Dioxide interacts more strongly with coal than methane

Mountziaris, T. J.

347

Dynamic energy budget approaches for modelling organismal ageing  

Science Journals Connector (OSTI)

...12 November 2010 research-article Articles...Developments in dynamic energy budget theory and...metabolism. The Dynamic Energy Budgets (DEB...uptake and use of energy by living organisms...fate. From a more abstract and generic point...efforts, several research groups have used...

2010-01-01T23:59:59.000Z

348

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

349

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

350

Dynamic Transition in the Structure of an Energetic Crystal during Chemical Reactions at Shock Front Prior to Detonation  

E-Print Network (OSTI)

Front Prior to Detonation Ken-ichi Nomura, Rajiv K. Kalia, Aiichiro Nakano, and Priya Vashishta at shock fronts prior to detonation. Shock sensitivity measurements provide widely varying results that detonation is preceded by a transition from a diffuse shock front with well-ordered molecular dipoles behind

Southern California, University of

351

SiO2 stishovite under high pressure: Dielectric and dynamical properties and the ferroelastic phase transition  

E-Print Network (OSTI)

ferroelastic phase transition to the CaCl2 structure are investigated using density-functional theory rutile structure to the orthorhombic CaCl2 structure. The on-site and interatomic force constants and the phonon frequencies at the point are also com- puted in the CaCl2 structure. S0163-1829 97 03636-9 I

Oganov, Artem R.

352

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

353

Modeling and Algorithm for DynamicModeling and Algorithm for Dynamic Multi-Objective Max-CSPsMulti-Objective Max-CSPs  

E-Print Network (OSTI)

_n is blow m. ­ e.g. m=5 : No (3,3) / Yes (4,1) #12;Multi-Objective Max-CSP (Properties) For a cost vector RModeling and Algorithm for DynamicModeling and Algorithm for Dynamic Multi-Objective Max-CSPsMulti-Objective Max-CSPs Tenda Okimoto ¹², Tony Rebeiro ³, Maxime Clement and Katsumi Inoue ² ¹ Transdisciplinary

Banbara, Mutsunori

354

Analysis and modelling of glacial climate transitions using simple dynamical systems  

Science Journals Connector (OSTI)

...e2009-01087-5 ) 25 Johnsen, SJ , . 2001 Oxygen isotope and palaeotemperature records from six Greenland ice-core stations: Camp Century, Dye-3, GRIP, GISP2, Renland and NorthGRIP. J. Q. Sci. 16. 299-307. 10.1002/jqs.622 ( doi:10...

2013-01-01T23:59:59.000Z

355

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

356

Predictions from an Ising-like Statistical Mechanical Model on the Dynamic and Thermodynamic Effects of Protein Surface Electrostatics  

Science Journals Connector (OSTI)

Predictions from an Ising-like Statistical Mechanical Model on the Dynamic and Thermodynamic Effects of Protein Surface Electrostatics ...

Athi N. Naganathan

2012-10-05T23:59:59.000Z

357

DYNAMICAL MODEL FOR THE ZODIACAL CLOUD AND SPORADIC METEORS  

SciTech Connect

The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer ({approx}> 10{sup 5} yr at 1 AU) than postulated in the standard collisional models ({approx}10{sup 4} yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) Multiplication-Sign 10{sup 11} km{sup 2} and {approx}4 Multiplication-Sign 10{sup 19} g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be {approx}10{sup 4}-10{sup 5} kg s{sup -1}. The input is up to {approx}10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 {mu}m and 1 cm is found to be {approx}15,000 tons yr{sup -1} (factor of two uncertainty), which is a large share of the accretion flux measured by the Long Term Duration Facility. The majority of JFC particles plunge into the upper atmosphere at <15 km s{sup -1} speeds, should survive the atmospheric entry, and can produce micrometeorite falls. This could explain the compositional similarity of samples collected in the Antarctic ice and stratosphere, and those brought from comet Wild 2 by the Stardust spacecraft. Meteor radars such as CMOR and AMOR see only a fraction of the accretion flux ({approx}1%-10% and {approx}10%-50%, respectively), because small particles impacting at low speeds produce ionization levels that are below these radars' detection capabilities.

Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F. [Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 (United States); Janches, Diego [Space Weather Laboratory, Code 674, GSFC/NASA, Greenbelt, MD 20771 (United States); Jenniskens, Peter [Carl Sagan Center, SETI Institute, 515 N. Whisman Road, Mountain View, CA 94043 (United States)

2011-12-20T23:59:59.000Z

358

Towards Modeling Dynamic Behavior with Integrated Qualitative Spatial Relations  

Science Journals Connector (OSTI)

Situation awareness and geographic information systems in dynamic spatial systems such as road traffic management (RTM) aim to detect and predict critical situations on the basis of relations between entities....

Stefan Mitsch; Werner Retschitzegger…

2011-01-01T23:59:59.000Z

359

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

360

Dynamical Modeling of Economy in Global Nuclear Energy Market  

Science Journals Connector (OSTI)

Non-linear dynamical analysis for the global nuclear energy market is investigated. Currently, the market means a different characteristics comparing to the ... between two countries, which depends on the energy ...

Taeho Woo

2012-01-01T23:59:59.000Z

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.


361

Structural models of bioactive glasses from molecular dynamics simulations  

Science Journals Connector (OSTI)

...to adsorb and dissociate a water molecule (Tilocca Cormack 2008...the available computational power steadily grows, it will become...surface of bioactive glasses: water adsorption and reactivity...soda-lime silicate glasses by Car-Parrinello molecular dynamics...

2009-01-01T23:59:59.000Z

362

Predicting and understanding forest dynamics using a simple tractable model  

E-Print Network (OSTI)

the dynamics of size distributions and wood volume and, hence, carbon in even-aged plantation monocul- tures patterns in the biomass, structure, and species composition of forests (4). This problem limits our ability

Lichstein, Jeremy W.

363

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

364

Offshore floating vertical axis wind turbines, dynamics modelling state of the art. Part II: Mooring line and structural dynamics  

Science Journals Connector (OSTI)

Abstract The need to exploit enhanced wind resources far offshore as well as in deep waters requires the use of floating support structures to become economically viable. The conventional three-bladed horizontal axis wind turbine may not continue to be the optimal design for floating applications. Therefore it is important to assess alternative concepts in this context that may be more suitable. Vertical axis wind turbines (VAWTs) are a promising concept, and it is important to first understand the coupled and relatively complex dynamics of floating \\{VAWTs\\} to assess their technical feasibility. As part of this task, a series of articles have been developed to present a comprehensive literature review covering the various areas of engineering expertise required to understand the coupled dynamics involved in floating VAWTs. This second article focuses on the modelling of mooring systems and structural behaviour of floating VAWTs, discussing various mathematical models and their suitability within the context of developing a model of coupled dynamics. Emphasis is placed on computational aspects of model selection and development as computational efficiency is an important aspect during preliminary design stages. This paper has been written both for researchers new to this research area, outlining underlying theory whilst providing a comprehensive review of the latest work, and for experts in this area, providing a comprehensive list of the relevant references where the details of modelling approaches may be found.

Michael Borg; Maurizio Collu; Athanasios Kolios

2014-01-01T23:59:59.000Z

365

Modeling DNA in Confinement: A Comparison between the Brownian Dynamics and Lattice Boltzmann Method  

E-Print Network (OSTI)

Modeling DNA in Confinement: A Comparison between the Brownian Dynamics and Lattice Boltzmann from both the lattice Boltzmann method (LBM) and the Brownian dynamics simulations with fluctuating. We find that the lattice Boltzmann method is well-suited for long polymer chains as well

366

LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model  

E-Print Network (OSTI)

LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model 1 dynamics, lIre performed at four diameters behind a 95 kW wind turbine. The wake 111eaeasurement technique allows esti111ation of qUClsiinstantancou~ two dimensional wind fields in an area

367

Interoperability between a dynamic reliability modeling and a Systems Engineering process Principles and Case Study  

E-Print Network (OSTI)

element for interoperability with the tools and activities required for a dynamic reliability assessment. The case study is the dynamic assessment of availability of a feed-water control system in a power plant steam generator, presented in previous articles. Keywords: Systems engineering, systems modeling, RAMS

Paris-Sud XI, Université de

368

A density-independent glass transition in biological tissues  

E-Print Network (OSTI)

Cells must move through tissues in many important biological processes, including embryonic development, cancer metastasis, and wound healing. In these tissues, a cell's motion is often strongly constrained by its neighbors, leading to glassy dynamics. Recent work has demonstrated the existence of a non-equilibrium glass transition in self-propelled particle models for active matter, where the transition is driven by changes in density. However, this may not explain liquid-to-solid transitions in confluent tissues, where there are no gaps between cells and the packing fraction remains fixed and equal to unity. Here we demonstrate the existence of a different type of glass transition that occurs in the well-studied vertex model for confluent tissue monolayers. In this model, the onset of rigidity is governed by changes to single-cell properties such as cell-cell adhesion, cortical tension, and volume compressibility, providing an explanation for a liquid-to-solid transitions in confluent tissues.

Bi, Dapeng; Schwarz, J M; Manning, M Lisa

2014-01-01T23:59:59.000Z

369

Phase transitions in the two-dimensional single-ion anisotropic Heisenberg model with long-range interactions  

Science Journals Connector (OSTI)

Abstract In the present work, we investigate the effects of long-range interactions on the phase transitions of a two-dimensional Heisenberg model with single-ion anisotropy at zero and finite temperatures. The Hamiltonian is given by H = ? i ? j J ij ( S i x S j x + S i y S j y + ? S i z S j z ) + D ? i ( S i z ) 2 , where J ij = ? J | r j ? r i | ? p ( p ? 3 ) is a long-range ferromagnetic interaction ( J > 0 ) , 0 ? ? ? 1 is an anisotropic constant and D is the single-ion anisotropic constant. It is well-known that the single-ion anisotropy D creates a competition between an ordered state (favored by the exchange interaction) and a disordered state, even at zero temperature. For small values of D, the system has a spontaneous magnetization m z ? 0 , while in the large-D phase mz=0 because a state with ? S z ? ? 0 is energetically unfavorable. Therefore a phase transition takes a place in some critical value Dc due to quantum fluctuations. For systems with short-range interaction Dc?6 J (depending of ? constant) but in our model we have found larger values of D due to the higher cost to flip a spin. Since low-dimensional magnetic systems with long range interaction can be ordered at finite temperature, we also have analyzed the thermal phase transitions (similar to the BKT transition). The model has been studied by using a Schwinger boson formalism as well as the self-consistent harmonic approximation (SCHA) and both methods provide according results.

A.R. Moura

2014-01-01T23:59:59.000Z

370

An Energy-Aware Simulation Model and Transaction Protocol for Dynamic Workload Distribution in Mobile Ad Hoc Networks1  

E-Print Network (OSTI)

An Energy-Aware Simulation Model and Transaction Protocol for Dynamic Workload Distribution California {tari, prong, pedram}@usc.edu Abstract This paper introduces a network simulation model

Pedram, Massoud

371

Using NASA Remote Sensing Data to Reduce Uncertainty of Land-Use Transitions in Global Carbon-Climate Models: Data Management Plan  

E-Print Network (OSTI)

-use transitions and their inherent uncertainty. Our plan for managing these datasets includes quality assessmentUsing NASA Remote Sensing Data to Reduce Uncertainty of Land-Use Transitions in Global Carbon-Climate Models: Data Management Plan L. Chini, G.C. Hurtt, M. Hansen, and P. Potapov Department of Geography

372

Mott Insulator-Superfluid Transition in a Generalized Bose-Hubbard Model with Topologically Non-trivial Flat-Band  

E-Print Network (OSTI)

In this paper, we studied a generalized Bose-Hubbard model on a checkerboard lattice with topologically nontrivial flat-band. We used mean-field method to decouple the model Hamiltonian and obtained phase diagram by Landau theory of second-order phase transition. We further calculate the energy gap and the dispersion of quasi-particle or quasi-hole in Mott insulator state and found that in strong interaction limit the quasi-particles or the quasi-holes also have flat bands.

Xing-Hai Zhang; Su-Peng Kou

2012-05-30T23:59:59.000Z

373

Proposing a two-level stochastic model for epileptic seizure genesis  

Science Journals Connector (OSTI)

By assuming the brain as a multi-stable system, different scenarios have been introduced for transition from normal to epileptic state. But, the path through which this transition occurs is under debate. In this paper a stochastic model for seizure genesis ... Keywords: Dynamical model, EEG generator, Excitatory and inhibitory synaptic gains, Hidden Markov Model, Normal-to-seizure state transition, Seizure

F. Shayegh; S. Sadri; R. Amirfattahi; K. Ansari-Asl

2014-02-01T23:59:59.000Z

374

Dynamic screening x-ray energy shifts and collisional line broadening of 2p-1s transitions in 2 MeV/AMU H- and He-like Ne, Mg, and S ions traveling in solids  

E-Print Network (OSTI)

University in partial fulfillment of the requirements for the degree of BASTER OF SCIENCE December 1983 Na)or Sub)ect: Chemistry DYNAMIC SCREENING X-RAY ENERGY SHIFTS AND COLLISIONAL LINE BROADENING OF 2p-1s TRANSITIONS IN 2 Mev/AMU H- AND HE-LIKE NE...) December 1983 ABSTRACT Dynamic Screening X-Ray Energy Shifts and Collisional Line Broadening of 2p-1s Transitions in 2 Mev/AMU H- and He-like Ne, Mg, and S Tons Traveling in Solids (December 1983) Richard Jay Maurer, B. S. College of Charleston...

Maurer, Richard Jay

2012-06-07T23:59:59.000Z

375

Ensemble regression : using ensemble model output for atmospheric dynamics and prediction  

E-Print Network (OSTI)

Ensemble regression (ER) is a linear inversion technique that uses ensemble statistics from atmospheric model output to make dynamical inferences and forecasts. ER defines a multivariate regression operator using ensemble ...

Gombos, Daniel (Daniel Lawrence)

2009-01-01T23:59:59.000Z

376

Dynamic soil-structure interaction-comparison of FEM model with experimental results  

E-Print Network (OSTI)

to represent twenty different laboratory experiments. The results of these models are compared with results available from extensive experimental dynamic testing on a geotechnical centrifuge. Though the various results from the finite element analysis...

Srinivasan, Palanivel Rajan

2012-06-07T23:59:59.000Z

377

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...

Gaddamanugu, Dhatri

2010-07-14T23:59:59.000Z

378

A dynamic model of a self-vibration cycle in a stirling engine with opposed cylinders  

Science Journals Connector (OSTI)

A dynamic model of the self-vibration cycle in an engine with opposed cylinders and two pistons located on a common guide bar is studied. To each cylinder containing a working liquid, a pair of hydraulic accum...

M. Ya. Izrailovich; A. V. Sinev…

2007-06-01T23:59:59.000Z

379

Constraining dynamical dark energy models through the abundance of high-redshift supermassive black holes  

Science Journals Connector (OSTI)

......Constraining dynamical dark energy models through the abundance...its contribution to the energy density would become rapidly...provided by the NASA Joint Dark Energy Mission (JDEM) -Wide-Field Infrared Survey Telescope (WFIRST) space......

A. Lamastra; N. Menci; F. Fiore; C. Di Porto; L. Amendola

2012-03-01T23:59:59.000Z

380

Model predictive controller design for the dynamic positioning system of a semi-submersible platform  

Science Journals Connector (OSTI)

This paper researches how to apply the advanced control technology of model predictive control (MPC) to the design of the dynamic positioning system (DPS) of a semi-submersible platform. First, a linear low-frequ...

Hongli Chen; Lei Wan; Fang Wang…

2012-09-01T23:59:59.000Z

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.


381

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

Open Energy Info (EERE)

Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Mechanical...

382

A Dynamic household Alternative-fuel Vehicle Demand Model Using Stated and Revealed Transaction Information  

E-Print Network (OSTI)

market share for alternative-fuel vehicles drop from thePreferences for Alternative-Fuel Vehicles”, Brownstone DavidA Dynamic Household Alternative-fuel Vehicle Demand Model

Sheng, Hongyan

1999-01-01T23:59:59.000Z

383

Groundwater pollution from agrochemicals — A dynamic model of externalities and policy options  

Science Journals Connector (OSTI)

A dynamic model of groundwater pollution from intensive agrochemical use is developed in this paper to capture the possible externalities and analyze various policy options in protecting groundwater resources. Fo...

Suresh Chandra Babu; B. Thirumalai Nivas; B. Rajasekaran

1992-01-01T23:59:59.000Z

384

Modeling the Complex Dynamics of Distributed Communities of the Web with Pretopology  

E-Print Network (OSTI)

Modeling the Complex Dynamics of Distributed Communities of the Web with Pretopology Vincent analysis of web communities. This approach is based upon the pretopological concepts of pseudoclosure through the actual limits of graph theory modeling. The problem of modeling and understanding web

385

Model-based control strategies in the dynamic interaction of air supply and fuel cell  

E-Print Network (OSTI)

Model-based control strategies in the dynamic interaction of air supply and fuel cell M Grujicic1Ã? fuel cell temperature. The model is used to analyse the control of the fuel cell system with respect, University of Michigan, Ann Arbor, Michigan, USA Abstract: Model-based control strategies are utilized

Grujicic, Mica

386

Small-signal dynamic model of a micro-grid including conventional and electronically  

E-Print Network (OSTI)

Small-signal dynamic model of a micro-grid including conventional and electronically interfaced-signal modelling of a micro-grid system that includes conventional (rotating machine) and electronically interfaced deviations in the overall system model and provides a methodology for the analysis of autonomous micro-grid

Lehn, Peter W.

387

Transmission Dynamics of an Influenza Model with Age of Infection ...  

E-Print Network (OSTI)

viral treatment and drug-resistance. In this paper, we consider an influenza model which includes an age of infection. The model includes partial differential ...

2010-07-20T23:59:59.000Z

388

Quantum-to-classical transition and entanglement sudden death in Gaussian states under local-heat-bath dynamics  

SciTech Connect

Entanglement sudden death (ESD) in spatially separated two-mode Gaussian states coupled to local thermal and squeezed thermal baths is studied by mapping the problem to that of the quantum-to-classical transition. Using Simon's criterion concerning the characterization of classicality in Gaussian states, the time to ESD is calculated by analyzing the covariance matrices of the system. The results for the two-mode system at T=0 and T>0 for the two types of bath states are generalized to n modes, and are shown to be similar in nature to the results for the general discrete n-qubit system.

Goyal, Sandeep K.; Ghosh, Sibasish [Center for Quantum Sciences, Institute of Mathematical Sciences, CIT Campus, Taramani, Chennai 600 113 (India)

2010-10-15T23:59:59.000Z

389

Quantification of model mismatch errors of the dynamic energy distribution in a stirred-tank reactor  

E-Print Network (OSTI)

QUANTIFICATION OF MODEL MISMATCH ERRORS OF THE DYNAMIC ENERGY DISTRIBUTION IN A STIRRED- TANK REACTOR A Thesis by MARK RAYMOND KIMMICH Submitted to the Graduate College of Texas AkM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 198i Major Subject: Chemical Engineering QUANTIFICATION OF MODEL MISMATCH ERRORS OF THE DYNAMIC ENERGY DISTRIBUTION IN A STIRRED-TANK REACTOR A Thesis by MARK RAYMOND KIMMICH Approved as to style and content by...

Kimmich, Mark Raymond

1987-01-01T23:59:59.000Z

390

Generator Dynamic Model Validation and Parameter Calibration Using Phasor Measurements at the Point of Connection  

SciTech Connect

Disturbance data recorded by phasor measurement units (PMU) offers opportunities to improve the integrity of dynamic models. However, manually tuning parameters through play-back events demands significant efforts and engineering experiences. In this paper, a calibration method using the extended Kalman filter (EKF) technique is proposed. The formulation of EKF with parameter calibration is discussed. Case studies are presented to demonstrate its validity. The proposed calibration method is cost-effective, complementary to traditional equipment testing for improving dynamic model quality.

Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Steve

2013-05-01T23:59:59.000Z

391

Dynamic modeling and simulation of a solar-assisted multi-effect distillation plant  

Science Journals Connector (OSTI)

Abstract This paper presents a dynamic model of a solar-assisted multi-effect distillation (MED) plant, carrying on with the previous work “Dynamic modeling and performance of the first cell of a multi-effect distillation plant” (de la Calle et al., 2014). The dynamic model has been designed according to the experience with an experimental solar thermal desalination system erected at CIEMAT-Plataforma Solar de Almería (PSA). The mathematical formulation based on physical principles describes the main heat and mass transfer phenomena in this kind of facilities. The model was implemented using the equation-based object-oriented Modelica modeling language. Based on a modular and hierarchical modeling, different specific-phenomenon submodels have been developed. They have been interconnected between them, thus making a three level deep hierarchy. All the submodels have been calibrated and validated with experimental data. The numerical predictions show a good agreement with measured data.

Alberto de la Calle; Javier Bonilla; Lidia Roca; Patricia Palenzuela

2015-01-01T23:59:59.000Z

392

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

393

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

394

Dynamic Models for Liquid Rocket Engines with Health Monitoring Application  

E-Print Network (OSTI)

) is considered and reviewed, taking as a reference the thermodynamic model introduced by Rocketdyne

395

Dynamically dimensioned search algorithm for computationally efficient watershed model calibration  

E-Print Network (OSTI)

search (DDS), is introduced for automatic calibration of watershed simulation models. DDS is designed. Introduction [2] Almost all watershed simulation models contain effective physical and/or conceptual model. This study will focus on the automatic calibration of watershed simulation models. The results of this study

Hutter, Frank

396

Analytic theory of L{yields}H transition, barrier structure, and hysteresis for a simple model of coupled particle and heat fluxes  

SciTech Connect

The two-field (pressure/density) model for the L{yields}H transition is extended and analyzed qualitatively. In its original form the model is ambiguous as to the location of the transition within the range of bistability of particle and thermal fluxes. Here, the model is regularized by including (i) hyperdiffusion, (ii) time dependence, and (iii) curvature of the pressure profile. The regularizations (i)-(ii) agree and indicate that the Maxwell rule for the forward and back transition applies, as opposed to the maximum flux forward and minimum flux backward transition rules (which yields hysteresis) as suggested previously. Regarding (i)-(ii), simple models suggest that for a pressure gradient driven electric field shear bifurcation, the basic scale of the pedestal is inexorably tied to the particle fueling depth, which normally is the neutral penetration depth. There is no hysteresis predicted by the local model of transport suppression. However, the effect of pressure profile curvature (iii) changes these results substantially. When it dominates, the curvature effect reduces the transition threshold to the lower end of the range of heating power, which falls within the phase coexistence region for both forward and back transitions. This softens the transition threshold requirements. In this limit, the model with pressure curvature also predicts transitions which occur in regimes of flat density and driven exclusively by the temperature gradient. This allows the pedestal to extend beyond the fueling depth, and also allows some decoupling of density and pressure profiles. In a parameter range where the pressure curvature is less important the transition occurs somewhere between the above two limits.

Malkov, M. A.; Diamond, P. H. [Center for Astrophysics and Space Sciences and Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)

2008-12-15T23:59:59.000Z

397

Variational Inference in Stochastic Dynamic Environmental Models Dan Cornford1  

E-Print Network (OSTI)

on related phenomena, such as flooding and storm damage, and on the spread of pollutants. The models needed of the atmosphere even at the resolution of the model. This is especially problematic if the simulation

Roulstone, Ian

398

A dynamic process model of a natural gas combined cycle -- Model development with startup and shutdown simulations  

SciTech Connect

Research in dynamic process simulation for integrated gasification combined cycles (IGCC) with carbon capture has been ongoing at the National Energy Technology Laboratory (NETL), culminating in a full operator training simulator (OTS) and immersive training simulator (ITS) for use in both operator training and research. A derivative work of the IGCC dynamic simulator has been a modification of the combined cycle section to more closely represent a typical natural gas fired combined cycle (NGCC). This paper describes the NGCC dynamic process model and highlights some of the simulator’s current capabilities through a particular startup and shutdown scenario.

Liese, Eric [U.S. DOE; Zitney, Stephen E. [U.S. DOE

2013-01-01T23:59:59.000Z

399

Control Oriented Dynamic Modeling of a Turbocharged Diesel Engine  

Science Journals Connector (OSTI)

To build a precise model is a key issue in fulfilling on optimal control of the turbocharged diesel engine. Meanvalue model has been extensively used for engine control, but neglects the scavenging efficiency. On the basis of carefully considering air-fuel ... Keywords: Diesel engine, mean-value model, AFR

Haiyan Wang; Jundong Zhang

2006-10-01T23:59:59.000Z

400

Transitions of cloud-topped marine boundary layers characterized by AIRS, MODIS, and a large eddy simulation model  

SciTech Connect

Cloud top entrainment instability (CTEI) is a hypothesized positive feedback between entrainment mixing and evaporative cooling near the cloud top. Previous theoretical and numerical modeling studies have shown that the persistence or breakup of marine boundary layer (MBL) clouds may be sensitive to the CTEI parameter. Collocated thermodynamic profile and cloud observations obtained from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) instruments are used to quantify the relationship between the CTEI parameter and the cloud-topped MBL transition from stratocumulus to trade cumulus in the northeastern Pacific Ocean. Results derived from AIRS and MODIS are compared with numerical results from the UCLA large eddy simulation (LES) model for both well-mixed and decoupled MBLs. The satellite and model results both demonstrate a clear correlation between the CTEI parameter and MBL cloud fraction. Despite fundamental differences between LES steady state results and the instantaneous snapshot type of observations from satellites, significant correlations for both the instantaneous pixel-scale observations and the long-term averaged spatial patterns between the CTEI parameter and MBL cloud fraction are found from the satellite observations and are consistent with LES results. This suggests the potential of using AIRS and MODIS to quantify global and temporal characteristics of the cloud-topped MBL transition.

Yue, Qing; Kahn, Brian; Xiao, Heng; Schreier, Mathias; Fetzer, E. J.; Teixeira, J.; Suselj, Kay

2013-08-16T23:59:59.000Z

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

Chiral phase transition in relativistic heavy-ion collisions with weak magnetic fields: Ring diagrams in the linear sigma model  

Science Journals Connector (OSTI)

Working in the linear sigma model with quarks, we compute the finite-temperature effective potential in the presence of a weak magnetic field, including the contribution of the pion ring diagrams and considering the sigma as a classical field. In the approximation where the pion self-energy is computed perturbatively, we show that there is a region of the parameter space where the effect of the ring diagrams is to preclude the phase transition from happening. Inclusion of the magnetic field has small effects that however become more important as the system evolves to the lowest temperatures allowed in the analysis.

Alejandro Ayala; Adnan Bashir; Alfredo Raya; Angel Sánchez

2009-08-10T23:59:59.000Z

402

Dynamic Inversion for Hydrological Process Monitoring with Electrical Resistance Tomography Under Model Uncertainty  

SciTech Connect

We propose an approach for imaging the dynamics of complex hydrological processes. The evolution of electrically conductive fluids in porous media is imaged using time-lapse electrical resistance tomography. The related dynamic inversion problem is solved using Bayesian filtering techniques, that is, it is formulated as a sequential state estimation problem in which the target is an evolving posterior probability density of the system state. The dynamical inversion framework is based on the state space representation of the system, which involves the construction of a stochastic evolution model and an observation model. The observation model used in this paper consists of the complete electrode model for ERT, with Archie's law relating saturations to electrical conductivity. The evolution model is an approximate model for simulating flow through partially saturated porous media. Unavoidable modeling and approximation errors in both the observation and evolution models are considered by computing approximate statistics for these errors. These models are then included in the construction of the posterior probability density of the estimated system state. This approximation error method allows the use of approximate - and therefore computationally efficient - observation and evolution models in the Bayesian filtering. We consider a synthetic example and show that the incorporation of an explicit model for the model uncertainties in the state space representation can yield better estimates than a frame-by-frame imaging approach.

Lehikoinen, A.; Huttunen, J.M.J.; Finsterle, S.; Kowalsky, M.B.; Kaipio, J.P.

2009-08-01T23:59:59.000Z

403

Dynamical System Approach to Cosmological Models with a Varying Speed of Light  

E-Print Network (OSTI)

Methods of dynamical systems have been used to study homogeneous and isotropic cosmological models with a varying speed of light (VSL). We propose two methods of reduction of dynamics to the form of planar Hamiltonian dynamical systems for models with a time dependent equation of state. The solutions are analyzed on two-dimensional phase space in the variables $(x, \\dot{x})$ where $x$ is a function of a scale factor $a$. Then we show how the horizon problem may be solved on some evolutional paths. It is shown that the models with negative curvature overcome the horizon and flatness problems. The presented method of reduction can be adopted to the analysis of dynamics of the universe with the general form of the equation of state $p=\\gamma(a)\\epsilon$. This is demonstrated using as an example the dynamics of VSL models filled with a non-interacting fluid. We demonstrate a new type of evolution near the initial singularity caused by a varying speed of light. The singularity-free oscillating universes are also admitted for positive cosmological constant. We consider a quantum VSL FRW closed model with radiation and show that the highest tunnelling rate occurs for a constant velocity of light if $c(a) \\propto a^n$ and $-1 < n \\le 0$. It is also proved that the considered class of models is structurally unstable for the case of $n < 0$.

Marek Szydlowski; Adam Krawiec

2002-12-16T23:59:59.000Z

404

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

405

Synchronization of pairwise-coupled, identical, relaxation oscillators based on metal-insulator phase transition devices: A Model Study  

E-Print Network (OSTI)

Computing with networks of synchronous oscillators has attracted wide-spread attention as novel materials and device topologies have enabled realization of compact, scalable and low-power coupled oscillatory systems. Of particular interest are compact and low-power relaxation oscillators that have been recently demonstrated using MIT (metal- insulator-transition) devices using properties of correlated oxides. This paper presents an analysis of the dynamics and synchronization of a system of two such identical coupled relaxation oscillators implemented with MIT devices. We focus on two implementations of the oscillator: (a) a D-D configuration where complementary MIT devices (D) are connected in series to provide oscillations and (b) a D-R configuration where it is composed of a resistor (R) in series with a voltage-triggered state changing MIT device (D). The MIT device acts like a hysteresis resistor with different resistances in the two different states. The synchronization dynamics of such a system has been analyzed with purely charge based coupling using a resistive (Rc) and a capacitive (Cc) element in parallel. It is shown that in a D-D configuration symmetric, identical and capacitively coupled relaxation oscillator system synchronizes to an anti-phase locking state, whereas when coupled resistively the system locks in phase. Further, we demonstrate that for certain range of values of Rc and Cc, a bistable system is possible which can have potential applications in associative computing. In D-R configuration, we demonstrate the existence of rich dynamics including non-monotonic flows and complex phase relationship governed by the ratios of the coupling impedance. Finally, the developed theoretical formulations have been shown to explain experimentally measured waveforms of such pairwise coupled relaxation oscillators.

Abhinav Parihar; Nikhil Shukla; Suman Datta; Arijit Raychowdhury

2014-08-11T23:59:59.000Z

406

Dynamic behavior of the monomermonomer surface reaction model with adsorbate interactions  

E-Print Network (OSTI)

Dynamic behavior of the monomer­monomer surface reaction model with adsorbate interactions model with an adsorbate interaction term is studied. An epidemic analysis of the poisoning times (tp between the concentration of molecules adsorbed on the surface and the rate of adsorp- tion

Voigt, Chris

407

A. Ford and H. Flynn: Statistical Screening of Models 273 Statistical screening of system dynamics  

E-Print Network (OSTI)

in the information spectrum in Figure 1. Hard sources include physical laws and the results of controlled experimentsA. Ford and H. Flynn: Statistical Screening of Models 273 Statistical screening of system dynamics models Andrew Forda * and Hilary Flynnb Abstract This paper describes a pragmatic method of searching

Ford, Andrew

408

Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu  

E-Print Network (OSTI)

Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu Human Factors in several ways. Modeling the impact of one such difference raised theoretical issues in motor movement and attention. For motor movement, the issue concerned the functional shape and size of a target

Gray, Wayne

409

A simple Markov model of sodium channels with a dynamic threshold  

Science Journals Connector (OSTI)

Characteristics of action potential generation are important to understanding brain functioning and, thus, must be understood and modeled. It is still an open question what model can describe concurrently the phenomena of sharp spike shape, the spike ... Keywords: Conductance-based neurons, Divisive effect, Dynamic patch-clamp, Sodium channels, Spike shape, Spike threshold

A. V. Chizhov; E. Yu. Smirnova; K. Kh. Kim; A. V. Zaitsev

2014-08-01T23:59:59.000Z

410

FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY  

E-Print Network (OSTI)

FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY Prabir Daripa. Relevance of this HS model based result to EOR is established by performing direct numerical simulations of fully developed tertiary displacement in porous media. Results of direct numer- ical simulation

Daripa, Prabir

411

Protecting the African elephant: A dynamic bioeconomic model of ivory trade  

E-Print Network (OSTI)

Protecting the African elephant: A dynamic bioeconomic model of ivory trade G. Cornelis van Kooten Accepted 25 May 2008 Available online 7 July 2008 Keywords: Economics Elephant conservation Ivory trade ban on the protection of the African elephant (Laxadonta africana). The model consists of four ivory exporting regions

412

A model of sediment resuspension and transport dynamics in southern Lake Michigan  

E-Print Network (OSTI)

A model of sediment resuspension and transport dynamics in southern Lake Michigan Jing Lou-three-dimensional suspended sediment transport model was developed and generalized to include combined wave-current effects to study bottom sediment resuspension and transport in southern Lake Michigan. The results from a three

413

Liquid Water Dynamics in a Model Polymer Electrolyte Fuel Cell Flow Channel  

E-Print Network (OSTI)

Liquid Water Dynamics in a Model Polymer Electrolyte Fuel Cell Flow Channel by Chris Miller in a Model Polymer Electrolyte Fuel Cell Flow Channel by Chris Miller Bachelors of Engineering, University in a polymer electrolyte fuel cell is a critical issue in ensuring high cell performance. The water production

Victoria, University of

414

Modeling of quasistatic and dynamic load responses of filled viscoelastic materials  

E-Print Network (OSTI)

are typically used for static finite element analysis (see [9]). The CRSC/Lord team worked, both theoreticallyModeling of quasi­static and dynamic load responses of filled viscoelastic materials H.T. Banks factors to the complications arising in the process of formulating models. Damping is highly complex

415

Transient dynamics and food–web complexity in the Lotka–Volterra cascade model  

Science Journals Connector (OSTI)

...research-article Transient dynamics and food-web complexity in the Lotka-Volterra cascade...behaviour near equilibrium of model food webs correlate with their short-term transient...Lotka-Volterra cascade model of food webs provide the first evidence to answer this...

2001-01-01T23:59:59.000Z

416

Towards a Formal Semantics for a Structurally Dynamic Noncausal Modelling Language  

E-Print Network (OSTI)

, many of these languages are referred to as object-oriented mod- elling languages. Modelica [23] is oneTowards a Formal Semantics for a Structurally Dynamic Noncausal Modelling Language John Capper, UK nhn@cs.nott.ac.uk Abstract Modelling and simulation languages are evolving rapidly to sup- port

Nilsson, Henrik

417

Integrating Models and Simulations of Continuous Dynamics into SysML  

E-Print Network (OSTI)

and the corresponding Modelica models; and the integration of simulation experiments with other SysML constructsIntegrating Models and Simulations of Continuous Dynamics into SysML Thomas Johnson1 Christiaan J.J. Paredis1 Roger Burkhart2 1 Systems Realization Laboratory The G. W. Woodruff School of Mechanical

418

VOLUME 81, NUMBER 8 P H Y S I C A L R E V I E W L E T T E R S 24 AUGUST 1998 Nonequilibrium Roughening Transition in a Simple Model  

E-Print Network (OSTI)

Roughening Transition in a Simple Model of Fungal Growth in 1 1 1 Dimensions Juan M. López and Henrik exhibits a continuous roughening transition far from equilibrium from a smooth (a 0) to a rough phase (a 1 the problem onto a directed percolation process. The model reproduces the roughening transition observed

Jensen, Henrik Jeldtoft

419

Approximating Metal-Insulator Transitions  

E-Print Network (OSTI)

We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate metal-insulator transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges which are at variance to the celebrated Aubry-Andre model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase similar to the divergence of the localization length in the insulating phase.

C. Danieli; K. Rayanov; B. Pavlov; G. Martin; S. Flach

2014-05-06T23:59:59.000Z

420

Offshore floating vertical axis wind turbines, dynamics modelling state of the art. Part III: Hydrodynamics and coupled modelling approaches  

Science Journals Connector (OSTI)

Abstract The need to further exploit offshore wind resources has pushed offshore wind farms into deeper waters, requiring the use of floating support structures to be economically sustainable. The use of conventional wind turbines may not continue to be the optimal design for floating applications. Therefore it is important to assess other alternative configurations in this context. Vertical axis wind turbines (VAWTs) are one promising configuration, and it is important to first understand the coupled and relatively complex dynamics of floating \\{VAWTs\\} to assess the technical feasibility. As part of this task, a series of articles have been developed to present a comprehensive literature review covering the various areas of engineering expertise required to understand the coupled dynamics involved in floating VAWTs. This third article focuses on approaches to develop an efficient coupled model of dynamics (considering aerodynamics, hydrodynamics, structural and mooring line dynamics, and control dynamics) for floating VAWTs, as well as suitable ‘semi-analytical’ hydrodynamic models for this type of coupled dynamics models. Emphasis is also placed on utilising computationally efficient models and programming strategies. A comparison of the various forces acting on a floating VAWT with the three main floating support structure (spar, semi-submersible and tension-leg-platform) is also presented to highlight the relative dominant forces and hence importance of model accuracy representing these forces. Lastly a concise summary covering this series of articles is presented to give the reader an overview of this interdisciplinary research area. This article has been written both for researchers new to this research area, outlining underlying theory whilst providing a comprehensive review of the latest work, and for experts in this area, providing a comprehensive list of the relevant references where the details of modelling approaches may be found.

Michael Borg; Maurizio Collu

2014-01-01T23:59:59.000Z

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.


421

Dynamic Models for Wind Turbines and Wind Power Plants  

SciTech Connect

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

422

Patch Occupancy Models of Metapopulation Dynamics: Ef?cient ...  

E-Print Network (OSTI)

with spatial data on patch occupancyv The latter data are more readily available. ... and it can be adapted to any stochastic patch occupancy model of ...

423

Transmission Dynamics of an Influenza Model with Vaccination and ...  

E-Print Network (OSTI)

Jun 30, 2009 ... promised if drug-resistant strains arise. In this paper, we develop a mathematical model to explore the impact of vaccination and antiviral ...

2010-01-15T23:59:59.000Z

424

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

425

Structural-chemical modeling of transition of coals to the plastic state  

SciTech Connect

The structural-chemical simulation of the formation of plastic state during the thermal treatment (pyrolysis, coking) of coals is based on allowance for intermolecular interactions in the organic matter. The feasibility of transition of coals to the plastic state is determined by the ratio between the onset plastic state (softening) and runaway degradation temperatures, values that depend on the petrographic composition and the degree of metamorphism of coals and the distribution of structural and chemical characteristics of organic matter. 33 refs., 8 figs., 2 tabs.

A.M. Gyul'maliev; S.G. Gagarin [FGUP Institute for Fossil Fuels, Moscow (Russian Federation)

2007-02-15T23:59:59.000Z

426

Dynamic model of anisotropic x-ray refraction  

Science Journals Connector (OSTI)

General mechanisms of anisotropic x-ray refraction at the resonance energy are investigated on the basis of dynamic-scattering theory. The deductions show that x rays within the crystals that have anisotropic susceptibility are completely polarized and have two elliptical polarization states. Analytical expressions of the elliptical axes, refractive indices, and absorption coefficients for these two types of polarized waves are obtained in terms of the anisotropic components of the susceptibility tensor. Anisotropic birefringence and dichroism effects associated with the polarization properties of the x-ray waves are also illustrated theoretically.

X. R. Huang, Yong Li, W. J. Liu, and S. S. Jiang

1997-11-01T23:59:59.000Z

427

Relativistic Dynamical Collapse Model for a Scalar Field  

E-Print Network (OSTI)

A natural generalization of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied to a relativistic quantum scalar field $\\phi({\\bf x},t)$. It is shown that the modified Schr\\"odinger equation is relativistically invariant, that the probabilities associated to all possible values of the classical scalar random field $w({\\bf x},t)$ (which determines the eventual state of collapse) add up to 1, that there is no energy production out of the vacuum and, in the limit of large time, the collapse is toward eigenstates of $\\phi({\\bf x},0)$.

Philip Pearle

2014-04-26T23:59:59.000Z

428

Growing smooth interfaces with inhomogeneous, moving external fields: dynamical transitions, devil's staircases and self-assembled ripples  

E-Print Network (OSTI)

We study the steady state structure and dynamics of an interface in a pure Ising system on a square lattice placed in an inhomogeneous external field. The field has a profile with a fixed shape designed to stabilize a flat interface, and is translated with velocity v_e. For small v_e, the interface is stuck to the profile, is macroscopically smooth, and is rippled with a periodicity in general incommensurate with the lattice parameter. For arbitrary orientations of the profile, the local slope of the interface locks in to one of infinitely many rational values (devil's staircase) which most closely approximates the profile. These ``lock-in'' structures and ripples dissappear as v_e increases. For still larger v_e the profile detaches from the interface which is now characterized by standard Kardar-Parisi-Zhang (KPZ) exponents.

Abhishek Chaudhuri; P. A. Sreeram; Surajit Sengupta

2002-07-17T23:59:59.000Z

429

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

Science Journals Connector (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

430

Dynamical instabilities in density-dependent hadronic relativistic models  

SciTech Connect

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

431

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

432

Modeling dynamic conditional correlations in WTI oil forward and futures returns  

Science Journals Connector (OSTI)

This paper estimates the dynamic conditional correlations in the daily returns on West Texas Intermediate (WTI) oil forward and futures prices from 3 January 1985 to 16 January 2004, using recently developed multivariate conditional volatility models. We find that the dynamic conditional correlations can vary dramatically, being negative in four of ten cases and being close to zero in another five cases. Only in the case of the dynamic volatilities of the three-month and six-month futures returns is the range of variation relatively narrow, namely (0.832, 0.996).

Alessandro Lanza; Matteo Manera; Michael McAleer

2006-01-01T23:59:59.000Z

433

Ion-trap simulation of the quantum phase transition in an exactly solvable model of spins coupled to bosons  

SciTech Connect

It is known that arrays of trapped ions can be used to efficiently simulate a variety of many-body quantum systems. Here we show how it is possible to build a model representing a spin chain interacting with bosons that is exactly solvable. The exact spectrum of the model at zero temperature and the ground-state properties are studied. We show that a quantum phase transition occurs when the coupling between spins and bosons reaches a critical value, which corresponds to a level crossing in the energy spectrum. Once the critical point is reached, the number of bosonic excitations in the ground state, which can be assumed as an order parameter, starts to be different from zero. The population of the bosonic mode is accompanied by a macroscopic magnetization of the spins. This double effect could represent a useful resource for phase transition detection since a measure of the phonon can give information about the phase of the spin system. A finite-temperature phase diagram is also given in the adiabatic regime.

Giorgi, Gian Luca; Galve, Fernando [Instituto de Fisica Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca (Spain); Paganelli, Simone [Grup de Fisica Teorica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)

2010-05-15T23:59:59.000Z

434

Ion-trap simulation of the quantum phase transition in an exactly solvable model of spins coupled to bosons  

Science Journals Connector (OSTI)

It is known that arrays of trapped ions can be used to efficiently simulate a variety of many-body quantum systems. Here we show how it is possible to build a model representing a spin chain interacting with bosons that is exactly solvable. The exact spectrum of the model at zero temperature and the ground-state properties are studied. We show that a quantum phase transition occurs when the coupling between spins and bosons reaches a critical value, which corresponds to a level crossing in the energy spectrum. Once the critical point is reached, the number of bosonic excitations in the ground state, which can be assumed as an order parameter, starts to be different from zero. The population of the bosonic mode is accompanied by a macroscopic magnetization of the spins. This double effect could represent a useful resource for phase transition detection since a measure of the phonon can give information about the phase of the spin system. A finite-temperature phase diagram is also given in the adiabatic regime.

Gian Luca Giorgi; Simone Paganelli; Fernando Galve

2010-05-27T23:59:59.000Z

435

Ion-trap simulation of the quantum phase transition in an exactly solvable model of spins coupled to bosons  

E-Print Network (OSTI)

It is known that arrays of trapped ions can be used to efficiently simulate a variety of many-body quantum systems. Here, we show how it is possible to build a model representing a spin chain interacting with bosons which is exactly solvable. The exact spectrum of the model at zero temperature and the ground state properties are studied. We show that a quantum phase transition occurs when the coupling between spins and bosons reaches a critical value, which corresponds to a level crossing in the energy spectrum. Once the critical point is reached, the number of bosonic excitations in the ground state, which can be assumed as an order parameter, starts to be different from zero. The population of the bosonic mode is accompanied by a macroscopic magnetization of the spins. This double effect could represent an useful resource for the phase transition detection since a measure on the phonon can give information about the phase of the spin system. A finite temperature phase diagram is also given in the adiabatic regime.

Gian Luca Giorgi; Simone Paganelli; Fernando Galve

2010-02-01T23:59:59.000Z

436

Dynamic modeling of an integrated air-to-air heat pump using Modelica  

Science Journals Connector (OSTI)

Heat pump systems have gained significant market shares in Europe recently. The control strategy is an asset for the efficient operation of these thermodynamic systems; especially with compact integrated components. The predictive control, which allows fast system stabilization, is based on the description of the system physical behavior. Thus, dynamic modeling is needed for the development of such control. The model has to represent the system response to usual external perturbations met during current operation such as the variation of air temperature and air mass flow rate. The aim of this paper is to present a dynamic model of a thermodynamic system developed in the Dymola environment, which is an object-oriented modeling environment. The heat-pump components are created separately as individual objects, and then connected to form the system. The model of each component is described and the responses to different perturbations are detailed. Simulation results are compared to test results in order to validate the model.

S. Mortada; A. Zoughaib; D. Clodic; C. Arzano-Daurelle

2012-01-01T23:59:59.000Z

437

A hybrid dynamic and fuzzy time series model for mid-term power load forecasting  

Science Journals Connector (OSTI)

Abstract A new hybrid model for forecasting the electric power load several months ahead is proposed. To allow for distinct responses from individual load sectors, this hybrid model, which combines dynamic (i.e., air temperature dependency of power load) and fuzzy time series approaches, is applied separately to the household, public, service, and industrial sectors. The hybrid model is tested using actual load data from the Seoul metropolitan area, and its predictions are compared with those from two typical dynamic models. Our investigation shows that, in the case of four-month forecasting, the proposed model gives the actual monthly power load of every sector with only less than 3% absolute error and satisfactory reduction of forecasting errors compared to other models from previous studies.

Woo-Joo Lee; Jinkyu Hong

2015-01-01T23:59:59.000Z

438

Dynamical phase space from a SO(d,d) matrix model  

E-Print Network (OSTI)

It is shown that a matrix model with SO($d,d$) global symmetry is derived from a generalized Yang-Mills theory on the standard Courant algebroid. This model keeps all the positive features of the well-studied type IIB matrix model, and it has many additional welcome properties. We show that it does not only capture the dynamics of spacetime, but it should be associated with the dynamics of phase space. This is supported by a large set of classical solutions of its equations of motion, which corresponds to phase spaces of noncommutative curved manifolds and points to a new mechanism of emergent gravity. The model possesses an additional symmetry that exchanges positions and momenta, in analogy to quantum mechanics. It is argued that the emergence of phase space in the model is an essential feature for the investigation of the precise relation of matrix models to string theory and quantum gravity.

Athanasios Chatzistavrakidis

2014-07-25T23:59:59.000Z

439

Phase transition and ferrimagnetic long-range order in the mixed-spin Heisenberg model with single-ion anisotropy  

Science Journals Connector (OSTI)

In the present paper, we study the quantum phase transition in the mixed-spin Heisenberg model with the single-ion anisotropy on a bipartite lattice. We prove rigorously that, when the single-ion anisotropy energy D is positive, the model has a unique ground state with the total spin-z component Sz=0. On the other hand, when the single-ion anisotropy energy is negative and favors the longitudinal spin direction, the global ground state of the system becomes doubly degenerate. Therefore, D=0 is the bifurcation point for the global ground state of the system. Furthermore, we show also that, in the latter case, the global ground state of the mixed-spin Heisenberg chain has the ferrimagnetic long-range order. Our conclusions confirm and generalize the previous results derived by numerical calculations on small size samples.

Guang-Shan Tian and Hai-Qing Lin

2004-09-21T23:59:59.000Z

440

The missing cavities in the SEEDS polarized scattered light images of transitional protoplanetary disks: a generic disk model  

E-Print Network (OSTI)

Transitional circumstellar disks around young stellar objects have a distinctive infrared deficit around 10 microns in their Spectral Energy Distributions (SED), recently measured by the Spitzer Infrared Spectrograph (IRS), suggesting dust depletion in the inner regions. These disks have been confirmed to have giant central cavities by imaging of the submillimeter (sub-mm) continuum emission using the Submillimeter Array (SMA). However, the polarized near-infrared scattered light images for most objects in a systematic IRS/SMA cross sample, obtained by HiCIAO on the Subaru telescope, show no evidence for the cavity, in clear contrast with SMA and Spitzer observations. Radiative transfer modeling indicates that many of these scattered light images are consistent with a smooth spatial distribution for micron-sized grains, with little discontinuity in the surface density of the micron-sized grains at the cavity edge. Here we present a generic disk model that can simultaneously account for the general features in...

Dong, R; Zhu, Z; Hartmann, L; Whitney, B; Brandt, T; Muto, T; Hashimoto, J; Grady, C; Follette, K; Kuzuhara, M; Tanii, R; Itoh, Y; Thalmann, C; Wisniewski, J; Mayama, S; Janson, M; Abe, L; Brandner, W; Carson, J; Egner, S; Feldt, M; Goto, M; Guyon, O; Hayano, Y; Hayashi, M; Hayashi, S; Henning, T; Hodapp, K W; Honda, M; Inutsuka, S; Ishii, M; Iye, M; Kandori, R; Knapp, G R; Kudo, T; Kusakabe, N; Matsuo, T; McElwain, M W; Miyama, S; Morino, J -I; Moro-Martin, A; Nishimura, T; Pyo, T -S; Suto, H; Suzuki, R; Takami, M; Takato, N; Terada, H; Tomono, D; Turner, E L; Watanabe, M; Yamada, T; Takami, H; Usuda, T; Tamura, M

2012-01-01T23:59:59.000Z

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.


441

Structural Transitions of Solvent-Free Oligomer-Grafted Nanoparticles  

Science Journals Connector (OSTI)

Novel structural transitions of solvent-free oligomer-grafted nanoparticles are investigated by using molecular dynamics simulations of a coarse-grained bead-spring model. Variations in core size and grafting density lead to self-assembly of the nanoparticles into a variety of distinct structures. At the boundaries between different structures, the nanoparticle systems undergo thermoreversible transitions. This structural behavior, which has not been previously reported, deviates significantly from that of simple liquids. The reversible nature of these transitions in solvent-free conditions offers new ways to control self-assembly of nanoparticles at experimentally accessible conditions.

Alexandros Chremos and Athanassios Z. Panagiotopoulos

2011-09-01T23:59:59.000Z

442

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

443

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

444

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

SciTech Connect

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

445

Modeling Equilibrium Dynamics of the Benguela Current System  

Science Journals Connector (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

446

Investigating the dynamic behavior of biochemical networks using model families  

Science Journals Connector (OSTI)

......computing technology, a high performance computing environment is achieved...the models, the usage of high performance computing is mandatory (see Section...development of MMT2 is high performance computing. On the other hand, MMT2......

Marc Daniel Haunschild; Bernd Freisleben; Ralf Takors; Wolfgang Wiechert

2005-04-01T23:59:59.000Z

447

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

448

A computer-aided modelling analogue for lattice dynamics  

Science Journals Connector (OSTI)

A useful methodology to study lattice dynamics is presented in this paper. Our method is based on the analogous behaviour of electromagnetic waves in transmission lines. The parameters analysed include the optical and acoustical branches and the frequency gap. The electrical circuit is solved using commercial software (MicroCap ); therefore, our methodology would be easily implemented on different systems. Resumen. En este trabajo se presenta una metodología útil para estudiar dinámica de redes. Nuestro método se basa en el comportamiento análogo de las ondas electromagnéticas en las líneas de transmición. Los parámetros analizados incluyen las ramas óptica y acústica y el gap de frecuencia. El circuito eléctrico es resuelto utlizando un software comercial (MicroCap ); por lo que nuestra metodologiá puede ser fácilmente implementada en diferentes sistemas.

Daniel Vega; Sergio Vera; Alfredo Juan

1997-01-01T23:59:59.000Z

449

A LuGre Tire Friction Model with Exact Aggregate Dynamics Panagiotis Tsiotras, Efstathios Velenis and Michel Sorine  

E-Print Network (OSTI)

A LuGre Tire Friction Model with Exact Aggregate Dynamics Panagiotis Tsiotras, Efstathios Velenis and Michel Sorine Abstract-- The LuGre dynamic point contact friction model for the two-dimensional translation of a body on a surface has been used in the past to derive a model for the friction forces

Tsiotras, Panagiotis

450

Dynamic modelling of MSF plants for automatic control and simulation purposes: a survey  

Science Journals Connector (OSTI)

The successful development of a control system requires an appropriate definition of the control structure (i.e., selection of output, input and disturbance variables) and an efficient dynamical model on which the design, analysis and evaluation can be carried out. Thus, the confidence in the obtained results depends on the validity of the control structure and of the model used. For multistage flash (MSF) desalination processes, several dynamical models can be found in the literature. However, most of them are not suitable for analysis and control design purposes because they bring too many variables into play. The variables, which are sharing in the control system, normally constitute a reduced subset of the total variables that can be defined in the process. Moreover, a dynamical model suitable for control is simpler than the model derived from the physics of the underlying process. Hence, the selection of variables and the model building from the point of view of control design presents a compromise between the indispensable information contained in the model and the mathematical complexity proper of the design. In this paper, different models from the literature are analysed. Their advantages and drawbacks are described taking into account simulation and automatic control purposes. Moreover, a set of wished modelling facilities from the control engineer point of view is highlighted. Finally, a block-oriented library for Matlab/Simulink is presented, so that different plant configurations can be implemented as block diagram to simulate the system and to test control algorithms.

Adrian Gambler; Essameddin Badreddin

2004-01-01T23:59:59.000Z

451

LANGEVIN DYNAMICS OF THE TWO STAGE MELTING TRANSITION OF VORTEX MATTER IN Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} IN THE PRESENCE OF STRAIGHT AND OF TILTED COLUMNAR DEFECTS  

SciTech Connect

In this paper we use London Langevin molecular dynamics simulations to investigate the vortex matter melting transition in the highly anisotropic high-temperature superconductor material Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}#14; in the presence of low concentration of columnar defects (CDs). We reproduce with further details our previous results obtained by using Multilevel Monte Carlo simulations that showed that the melting of the nanocrystalline vortex matter occurs in two stages: a first stage melting into nanoliquid vortex matter and a second stage delocalization transition into a homogeneous liquid. Furthermore, we report on new dynamical measurements in the presence of a current that identifies clearly the irreversibility line and the second stage delocalization transition. In addition to CDs aligned along the c-axis we also simulate the case of tilted CDs which are aligned at an angle with respect to the applied magnetic field. Results for CDs tilted by 45{degree} with respect to c-axis show that the locations of the melting and delocalization transitions are not affected by the tilt when the ratio of flux lines to CDs remains constant. On the other hand we argue that some dynamical properties and in particular the position of the irreversibility line should be affected.

GOLDSCHMIDT, YADIN Y.; LIU, Jin-Tao

2007-08-07T23:59:59.000Z

452

Finite-size effects in kinetic phase transitions of a model reaction on a fractal surface: Scaling approach and Monte Carlo investigation  

Science Journals Connector (OSTI)

Finite-size effects in kinetic (irreversible) phase transitions, from reactive to poisoned states, occurring in model reactions are interpreted with the aid of a phenomenological scaling approach. The proposed arguments are tested by computer simulations of a model for the oxidation of carbon monoxide on a fractal surface. The critical exponents of the transitions displayed by the model and the exponents for the transient period of the reaction at criticality are evaluated. A crossover from a reactive steady state to a regime where the surface could be poisoned by each of the reactants is found and discussed.

Ezequiel V. Albano

1990-12-01T23:59:59.000Z

453

Development Of Control Oriented Electrical And Thermal Models Of An Electric Transit Bus Battery System.  

E-Print Network (OSTI)

??This thesis presents the insights derived from the empirical characterization, modeling, simulation, control-design, and verification tasks performed in developing energy storage system (ESS) controls for… (more)

Kunte, Harshad

2014-01-01T23:59:59.000Z

454

Integrated Market Modeling of Hydrogen Transition Scenarios with HyTrans  

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

Presentation by Paul Leiby of Oak Ridge National Laboratory at the Joint Meeting on Hydrogen Delivery Modeling and Analysis, May 8-9, 2007

455

Dynamic modeling of steam power cycles: Part II – Simulation of a small simple Rankine cycle system  

Science Journals Connector (OSTI)

This paper presents the second part of the work concerning the dynamic simulation of small steam cycle plants for power generation. The work is part of the preliminary study for a 600 kWe biomass fired steam power plant for which the complete open-loop, lumped parameter dynamic model of the steam cycle has been developed using the SimECS software described in Part I of this work. For these low-power plants, a dynamic simulation tool is especially useful because these systems must be designed to operate in transient mode for most of the time. The plant model presented here consists of the following components: feedwater pump, economizer, evaporator, superheater, impulse turbine, electrical generator and condenser. The primary heat source is modeled as a flue gas flow and no combustion models are incorporated yet to model the furnace. A description of the various components forming the complete steam cycle is given to illustrate the capabilities and modularity of the developed modeling technique. The model is first validated quantitatively against steady-state values obtained using a well known, reliable steady-state process modeling software. Subsequently, the dynamic validation is presented. Results can only be discussed based on the qualitative assessment of the observed trends because measurements are not available, being the plant in the preliminary design phase. The qualitative validation is based on four dynamic simulations involving three small step disturbances of different magnitude imposed on the pump rotational speed and on the flue gas mass flow and a single large ramp disturbance on the flue gas mass flow.

H. van Putten; P. Colonna

2007-01-01T23:59:59.000Z

456

Dynamic measurement and modeling of the Casimir force at the nanometer scale  

SciTech Connect

We present a dynamic method for measurement of the Casimir force with an atomic force microscope (AFM) with a conventional AFM tip. With this method, originally based on the phase of vibration of the AFM tip, we are able to verify the Casimir force at distances of nearly 6 nm with an AFM tip that has a radius of curvature of nearly 100 nm. Until now dynamic methods have been done using large metal spheres at greater distances. Also presented is a theoretical model based on the harmonic oscillator, including nonidealities. This model accurately predicts the experimental data.

Kohoutek, John; Wan, Ivy Yoke Leng; Mohseni, Hooman [Bio-Inspired Sensors and Optoelectronics Laboratory (BISOL), EECS, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208 (United States)

2010-02-08T23:59:59.000Z

457

Lurking Pathway Prediction And Pathway ODE Model Dynamic Analysis  

E-Print Network (OSTI)

regulated proteins in the transduction pro- cess. And by modeling the CCL2 pathway in MTB infected cells, J N K , cM Y C and P LC showed as the most significant modules. Hence, the drug treatments inhibit- ing J N K , cM Y C and P LC would effectively...

Zhang, Rengjing

2013-11-18T23:59:59.000Z

458

Isotope uptake dynamics in the Ostwald ripening model of recrystallization  

E-Print Network (OSTI)

The article is withdrawn since we decided not to publish it in the present form but to divide it in two parts. One of these parts concerns the mathematical aspects of Return Radius calculation and the rewritten article is already available arXiv:1201.4492 The second part will discuss the modelling of the Isotope Uptake and is still in preparation

Evgeny Lakshtanov; Leonid Lakshtanov

2011-05-07T23:59:59.000Z

459

DYNAMIC PHASORS IN MODELING, ANALYSIS AND CONTROL OF ENERGY  

E-Print Network (OSTI)

in: power electronics, electric drives and power systems. NEU Energy Processing Laboratory (1994) is a confluence of research and educational efforts: 1. Areas: power electronics, electric drives and power (ONR YIP) Systems Power Drives Electric Electronics Adaptive Converters Resonant Modeling Load

Stankoviæ, Aleksandar

460

Modelling the dynamical evolution of the Bootes dwarf spheroidal galaxy  

E-Print Network (OSTI)

We investigate a wide range of possible evolutionary histories for the recently discovered Bootes dwarf spheroidal galaxy, a Milky Way satellite. By means of N-body simulations we follow the evolution of possible progenitor galaxies of Bootes for a variety of orbits in the gravitational potential of the Milky Way. The progenitors considered cover the range from dark-matter-free star clusters to massive, dark-matter dominated outcomes of cosmological simulations. For each type of progenitor and orbit we compare the observable properties of the remnant after 10 Gyr with those of Bootes observed today. Our study suggests that the progenitor of Bootes must have been, and remains now, dark matter dominated. In general our models are unable to reproduce the observed high velocity dispersion in Bootes without dark matter. Our models do not support time-dependent tidal effects as a mechanism able to inflate significantly the internal velocity dispersion. As none of our initially spherical models is able to reproduce the elongation of Bootes, our results suggest that the progenitor of Bootes may have had some intrinsic flattening. Although the focus of the present paper is the Bootes dwarf spheroidal, these models may be of general relevance to understanding the structure, stability and dark matter content of all dwarf spheroidal galaxies.

M. Fellhauer; M. I. Wilkinson; N. W. Evans; V. Belokurov; M. J. Irwin; G. Gilmore; D. B. Zucker; J. T. Kleyna

2008-01-17T23:59:59.000Z

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

Static and Dynamic Debugging of Modelica Models Adrian Pop1  

E-Print Network (OSTI)

, Peter Fritzson1 , Francesco Casella2 1 Programming Environments Laboratory Department of Computer@elet.polimi.it Abstract The high abstraction level of equation-based object- oriented languages (EOO) such as Modelica has and algorithmic code debugging. Keywords: Modelica, Debugging, Modeling and Simulation, Transformations, Equations

Zhao, Yuxiao

462

A semi-analytic power balance model for low (L) to high (H) mode transition power threshold  

SciTech Connect

We present a semi-analytic model for low (L) to high (H) mode transition power threshold (P{sub th}). Two main assumptions are made in our study. First, high poloidal mode number drift resistive ballooning modes (high-m DRBM) are assumed to be the dominant turbulence driver in a narrow edge region near to last closed flux surface. Second, the pre-transition edge profile and turbulent diffusivity at the narrow edge region pertain to turbulent equipartition. An edge power balance relation is derived by calculating the dissipated power flux through both turbulent conduction and convection, and radiation in the edge region. P{sub th} is obtained by imposing the turbulence quench rule due to sheared E?×?B rotation. Evaluation of P{sub th} shows a good agreement with experimental results in existing machines. Increase of P{sub th} at low density (i.e., the existence of roll-over density in P{sub th} vs. density) is shown to originate from the longer scale length of the density profile than that of the temperature profile.

Singh, R., E-mail: rsingh129@yahoo.co.in [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Institute for Plasma Research, Bhat Gandhinagar 2382 428 (India); Jhang, Hogun [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kaw, P. K. [Institute for Plasma Research, Bhat Gandhinagar 2382 428 (India); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093 (United States); Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0424 (United States); Nordman, H. [Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Bourdelle, C. [Euratom-CEA Association, CEA/DSM/DRFC, CEA Cadarache F-13108 Saint-Paul-Lez-Durance (France); Loarte, A. [ITER Organization, Route de Vinon Sur Verdon, A. 13115 Saint Paul Lez Durance (France)

2014-06-15T23:59:59.000Z

463

Modeling the dynamics of tidally-interacting binary neutron stars up to merger  

E-Print Network (OSTI)

We propose an effective-one-body (EOB) model that describes the general relativistic dynamics of neutron star binaries from the early inspiral up to merger. Our EOB model incorporates an enhanced attractive tidal potential motivated by recent analytical advances in the post-Newtonian and gravitational self-force description of relativistic tidal interactions. No fitting parameters are introduced for the description of tidal interaction in the late, strong-field dynamics. We compare the model dynamics (described by the gauge invariant relation between binding energy and orbital angular momentum), and the gravitational wave phasing, with new high-resolution multi-orbit numerical relativity simulations of equal-mass configurations with different equations of state. We find agreement essentially within the uncertainty of the numerical data for all the configurations. Our model is the first semi-analytical model which captures the tidal amplification effects close to merger. It thereby provides the most accurate analytical representation of binary neutron star dynamics and waveforms currently available.

Sebastiano Bernuzzi; Alessandro Nagar; Tim Dietrich; Thibault Damour

2014-12-15T23:59:59.000Z

464

Multiple higher-order singularities and iso-dynamics in a simple glass-former model  

E-Print Network (OSTI)

We investigate the slow dynamics of a colloidal model with two repulsive length scales, whose interaction potential is the sum of a hard-core and a square shoulder. Despite the simplicity of the interactions, Mode-Coupling theory predicts a complex dynamic scenario: a fluid-glass line with two reentrances and a glass-glass line ending with multiple higher-order ($A_3$ or $A_4$) singularities. In this work we verify the existence of the two $A_4$ points by numerical simulations, observing subdiffusive behaviour of the mean-square displacement and logarithmic decay of the density correlators. Surprisingly, we also discover a novel dynamic behaviour generated by the competition between the two higher-order singularities. This results in the presence of special loci along which the dynamics is identical \\textit{at all} length and time scales.

Nicoletta Gnan; Gayatri Das; Matthias Sperl; Francesco Sciortino; Emanuela Zaccarelli

2014-07-15T23:59:59.000Z

465

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

466

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

467

Dynamics of strong-coupling models for cuprate superconductors: Exact results on finite lattices  

SciTech Connect

We discuss recent applications of exact numerical continued fraction expansion (CFE) techniques to calculate dynamical correlation functions of various strong-coupling models related to the high-temperature cuprate superconductors. For the two-dimensional square-lattice spin-1/2 Heisenberg antiferromagnet, we present exact results for the zero-temperature dynamical structure factor on finite-sized lattices and compare them to approximate results from a Schwinger boson mean-field theory, recently proposed by Arovas and Auerbach. We find that the mean-field theory represents a very good approximation to the exact spin excitation spectra and to the static spin correlations. We then investigation the dynamical spin-spin structure factor and the single-particle spectral function for finite model clusters with dopant induced hole-type charge carriers, in the strong-coupling limit of both the single-band Hubbard model (t-J-model) and the three-band Hubbard model (Kondo-Heisenberg model). Our results are consistent with the physical picture recently proposed by Zhang and Rice which implies an approximate mapping of the low-energy states in the three-band model onto an effective single-band theory. 33 refs., 4 figs.

Schuettler, H.B.; Chen, C.-X. (Georgia Univ., Athens, GA (USA). Center for Simulational Physics); Fedro, A.J. (Argonne National Lab., IL (USA) Northern Illinois Univ., Dekalb, IL (USA). Dept. of Physics)

1989-01-01T23:59:59.000Z

468

Model of thermally activated magnetization reversal in thin films of amorphous rare-earth-transition-metal alloys  

Science Journals Connector (OSTI)

Monte Carlo simulations on a two-dimensional lattice of magnetic dipoles have been performed to investigate the magnetic reversal by thermal activation in rare-earth-transition-metal (RE-TM) alloys. Three mechanisms of magnetization reversal were observed: nucleation dominated growth, nucleation followed by the growth of magnetic domains containing no seeds of unreversed magnetization, and nucleation followed by dendritic domain growth by successive branching in the motion of the domain walls. The domain structures are not fractal; however, the fractal dimension of the domain wall was found to be a good measure of the jaggedness of the domain boundary surface during the growth process. The effects of the demagnetizing field on the hysteretic and time-dependent properties of the thin films were studied and some limitations in the application of the Fatuzzo model on magneto-optic media are identified.

A. Lyberatos; J. Earl; R. W. Chantrell

1996-03-01T23:59:59.000Z

469

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

470

IMA Journal of Applied Mathematics (2002) 67, 419439 Modelling thermal front dynamics in microwave heating  

E-Print Network (OSTI)

an electric field is applied to materials with high resistivity, the dipole moments of the molecules alignIMA Journal of Applied Mathematics (2002) 67, 419­439 Modelling thermal front dynamics in microwave July 2000; revised on 6 December 2001] The formation and propagation of thermal fronts in a cylindrical

Xin, Jack

471

Proper Orthogonal Decomposition-Based Modeling, Analysis, and Simulation of Dynamic Wind Load  

E-Print Network (OSTI)

Proper Orthogonal Decomposition-Based Modeling, Analysis, and Simulation of Dynamic Wind Load.1061/ ASCE 0733-9399 2005 131:4 325 CE Database subject headings: Simulation; Wind loads; Buildings; Random on the decomposition of the covariance and XPSD matrices is presented. A physically meaningful linkage between the wind

Chen, Xinzhong

472

Time Series Prediction by Chaotic Modeling of Nonlinear Dynamical Systems Arslan Basharat+  

E-Print Network (OSTI)

Inc. Clifton Park, NY, USA arslan.basharat@kitware.com Mubarak Shah+ + University of Central Florida Orlando, FL, USA shah@cs.ucf.edu Abstract We use concepts from chaos theory in order to model nonlinear dynamical systems that exhibit deterministic be- havior. Observed time series from such a system can be em

Central Florida, University of

473

Efficient Dynamic Modeling, Numerical Optimal Control and Experimental Results for Various Gaits  

E-Print Network (OSTI)

. A fully three- dimensional dynamical model of Sony's four-legged robot is used to state an optimal control robots is still a challenge. For a given gait pattern, landing time and point of each leg are prescribed, i.e. they depend on parameters. The trajectory of each joint between lift-off and landing

Stryk, Oskar von

474

On the self-similarity assumption in dynamic models for large eddy simulations  

E-Print Network (OSTI)

that the present formulation of the DP is usually incompatible with its under- lying self-similarity assumption SSAOn the self-similarity assumption in dynamic models for large eddy simulations Daniele Carati eddy simulations and their underlying self-similarity assumption is discussed. The interpretation

Van Den Eijnden, Eric

475

Radiated seismic energy based on dynamic rupture models of faulting and Ralph J. Archuleta1  

E-Print Network (OSTI)

Radiated seismic energy based on dynamic rupture models of faulting Shuo Ma1 and Ralph J. Archuleta energy from three hypothetical crustal events, 30° dipping reverse fault, 60° dipping normal fault, and 0.34 MPa for the reverse, normal, and strike-slip faults, respectively. The energy distribution

Archuleta, Ralph

476

Modeling Malware Propagation in Networks of Smart Cell Phones with Spatial Dynamics  

E-Print Network (OSTI)

Modeling Malware Propagation in Networks of Smart Cell Phones with Spatial Dynamics Krishna and worm attacks tar- geted at cell phones have have bought to the forefront the seriousness of the security threat to this increasingly popular means of communication. The ability of smart cell phones

Sikdar, Biplab

477

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model  

E-Print Network (OSTI)

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model Geoffroy J isotherms of 4He in a silica aerogel be- come discontinuous below a critical temperature. We show by the aerogel structure, but to the disorder-driven critical point predicted for the athermal out

Boyer, Edmond

478

Modelling of pH dynamics in brain cells after stroke  

Science Journals Connector (OSTI)

...pH increases their production [21-23]. Ca2...responsible for the production and consumption of hydrogen ions and hence the...clinical practice. 2. Methods The pH dynamics model...metabolism including H+ production and consumption...

2011-01-01T23:59:59.000Z

479

EMULATING A GRAVITY MODEL TO INFER THE SPATIOTEMPORAL DYNAMICS OF AN INFECTIOUS DISEASE  

E-Print Network (OSTI)

EMULATING A GRAVITY MODEL TO INFER THE SPATIOTEMPORAL DYNAMICS OF AN INFECTIOUS DISEASE Roman grid. · Use pre-calculated matrices {Mtk}. GP-EMULATOR - BASED APPROACH · Based on constructing a new (proportions of zeros) on a pre-selected grid of parameters. · Second stage: We make inference based

Bjørnstad, Ottar Nordal

480

Effects of Dynamic Forcing on Hillslope Water Balance Models , L.E. Band  

E-Print Network (OSTI)

simulations of the hillslope. In this work we focus specifically on closure relations for hillslope water]. Briefly stated, our objective in this work is to study the effect of system transience on hillslope waterEffects of Dynamic Forcing on Hillslope Water Balance Models C. E. Kees , L.E. Band , and M

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.


481

Nonlinear dynamical systems with data and model uncertainties subjected to seismic loads  

E-Print Network (OSTI)

Nonlinear dynamical systems with data and model uncertainties subjected to seismic loads Christophe loads with data uncertainties for the nonlinearities. An application to a multisupported reactor coolant and Acoustics Dpt., 92141, Clamart cedex, France ABSTRACT This paper deals with data uncertainties

Paris-Sud XI, Université de

482

Modeling of impact dynamics of tennis ball with a flat surface  

E-Print Network (OSTI)

A two-mass model with a spring and a damper in the vertical direction, accounting for vertical translational motion and a torsional spring and a damper connecting the rotational motion of two masses is used to simulate the dynamics of a tennis ball...

Jafri, Syed M.

2005-08-29T23:59:59.000Z

483

Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics and Kinematics  

E-Print Network (OSTI)

Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics problems, particularly for high-speed Surface Effect Ships (SES) such as the recently proposed Harley FastShip and/or a surface-piercing body (ship), within the framework of potential flow theory. The three

Grilli, Stéphan T.

484

DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT  

E-Print Network (OSTI)

1 DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT CHAMOUN MARWAN to improve industrial energy efficiency, the development of a high temperature heat pump using water vapor as refrigerant is investigated. Technical problems restraining the feasibility of this industrial heat pump

Paris-Sud XI, Université de

485

Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua)  

E-Print Network (OSTI)

uniformity) to variations in input parameters (such as radio-frequency (rf) power, flow rate, dc bias, and energy balance equations inside a high-frequency, high-intensity electric field. Realistic simulation91 Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua

Nikolaou, Michael

486

Turbulent models of ice giant internal dynamics: Dynamos, heat transfer, and zonal flows  

E-Print Network (OSTI)

Turbulent models of ice giant internal dynamics: Dynamos, heat transfer, and zonal flows K Magnetic fields a b s t r a c t The ice giant planets, Uranus and Neptune, have magnetic fields to yield small-scale and disorganized turbulence. In agreement with ice giant observations, both

487

Global dynamics of a vector disease model with saturation incidence and time delay  

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......Journal of Applied Mathematics (2011) 76, 919-937 doi:10.1093/imamat/hxr013 Advance Access publication on March 17, 2011 Global dynamics of a vector disease model with saturation incidence and time delay RUI XU Institute of Applied Mathematics......

Rui Xu; Zhien Ma

2011-12-01T23:59:59.000Z

488

Modeling Sediment and Wood Storage and Dynamics in Small Mountainous Watersheds  

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85 Modeling Sediment and Wood Storage and Dynamics in Small Mountainous Watersheds Stephen T controls on supply and transport of sediment and wood in a small (approximately two square kilometers) basin in the Oregon Coast Range, typical of streams at the interface between episodic sediment and wood

489

Simplified dynamic models for control of riser slugging in offshore oil production  

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ForReview Only Simplified dynamic models for control of riser slugging in offshore oil production, Department of Chemical Engineering Keywords: oil production, two-phase flow, severe slugging, riser slugging for control of riser slugging in offshore oil production Esmaeil Jahanshahi, Sigurd Skogestad Department

Skogestad, Sigurd

490

Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink Arenas  

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1 Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink, USA, Fax: 617-432-4122, Abstract Many ice rink arenas have ice resurfacing equipment that uses fossil temperature distributions in ice rinks. The numerical results agree reasonably with the corresponding

Chen, Qingyan "Yan"

491

SURFACE ELASTICITY MODELS FOR STATIC AND DYNAMIC RESPONSE OF NANOSCALE BEAMS  

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SURFACE ELASTICITY MODELS FOR STATIC AND DYNAMIC RESPONSE OF NANOSCALE BEAMS by Chang Liu B) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) February 2010 © Chang Liu, 2010 #12;ii Abstract Nanoscale beam of nanoscale beams. The objective is to provide NEMS designers with an efficient set of tools that can predict