National Library of Energy BETA

Sample records for modeling transition dynamics

  1. Mesoscale modeling of phase transition dynamics of thermoresponsive polymers

    E-Print Network [OSTI]

    Li, Zhen; Li, Xuejin; Karniadakis, George Em

    2015-01-01

    We present a non-isothermal mesoscopic model for investigation of the phase transition dynamics of thermoresponsive polymers. Since this model conserves energy in the simulations, it is able to correctly capture not only the transient behavior of polymer precipitation from solvent, but also the energy variation associated with the phase transition process. Simulations provide dynamic details of the thermally induced phase transition and confirm two different mechanisms dominating the phase transition dynamics. A shift of endothermic peak with concentration is observed and the underlying mechanism is explored.

  2. Jamming transitions in force-based models for pedestrian dynamics

    E-Print Network [OSTI]

    Chraibi, Mohcine; Tordeux, Antoine; Nishinari, Katsuhiro; Schadschneider, Andreas; Seyfried, Armin

    2015-01-01

    Force-based models describe pedestrian dynamics in analogy to classical mechanics by a system of second order ordinary differential equations. By investigating the linear stability of two main classes of forces, parameter regions with unstable homogeneous states are identified. In this unstable regime it is then checked whether phase transitions or stop-and-go waves occur. Results based on numerical simulations show, however, that the investigated models lead to unrealistic behavior in form of backwards moving pedestrians and overlapping. This is one reason why stop-and-go waves have not been observed in these models. The unrealistic behavior is not related to the numerical treatment of the dynamic equations but rather indicates an intrinsic problem of this model class. Identifying the underlying generic problems gives indications how to define models that do not show such unrealistic behavior. As an example we introduce a new force-based model which produces realistic jam dynamics without the appearance of u...

  3. Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions for model systems

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Proton-coupled electron transfer reactions in solution: Molecular dynamics with quantum transitions A general minimal model for proton-coupled electron transfer PCET reactions in solution is presented. This model consists of three coupled degrees of freedom that represent an electron, a proton, and a solvent

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    and income on energy and oil demand. Energy Journal, 23(1):conventional oil supply and demand. But, interestingly,World crude oil and natural gas: a demand and supply model.

  5. DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS

    SciTech Connect (OSTI)

    X. Wang; X. Sun; H. Zhao

    2011-09-01

    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.

  6. Introduction to Focus Issue: Rhythms and Dynamic Transitions in Neurological Disease: Modeling, Computation, and Experiment

    SciTech Connect (OSTI)

    Kaper, Tasso J. Kramer, Mark A.; Rotstein, Horacio G.

    2013-12-15

    Rhythmic neuronal oscillations across a broad range of frequencies, as well as spatiotemporal phenomena, such as waves and bumps, have been observed in various areas of the brain and proposed as critical to brain function. While there is a long and distinguished history of studying rhythms in nerve cells and neuronal networks in healthy organisms, the association and analysis of rhythms to diseases are more recent developments. Indeed, it is now thought that certain aspects of diseases of the nervous system, such as epilepsy, schizophrenia, Parkinson's, and sleep disorders, are associated with transitions or disruptions of neurological rhythms. This focus issue brings together articles presenting modeling, computational, analytical, and experimental perspectives about rhythms and dynamic transitions between them that are associated to various diseases.

  7. Finite temperature spin-dynamics and phase transitions in spin-orbital models

    SciTech Connect (OSTI)

    Chen, C.-C.

    2010-04-29

    We study finite temperature properties of a generic spin-orbital model relevant to transition metal compounds, having coupled quantum Heisenberg-spin and Ising-orbital degrees of freedom. The model system undergoes a phase transition, consistent with that of a 2D Ising model, to an orbitally ordered state at a temperature set by short-range magnetic order. At low temperatures the orbital degrees of freedom freeze-out and the model maps onto a quantum Heisenberg model. The onset of orbital excitations causes a rapid scrambling of the spin spectral weight away from coherent spin-waves, which leads to a sharp increase in uniform magnetic susceptibility just below the phase transition, reminiscent of the observed behavior in the Fe-pnictide materials.

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

    SciTech Connect (OSTI)

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

    2008-06-01

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

  9. Hybrid Car-Parrinello/Molecular Mechanics Modelling of Transition Metal Complexes: Structure, Dynamics and Reactivity

    E-Print Network [OSTI]

    Guidoni, Leonardo

    Hybrid Car-Parrinello/Molecular Mechanics Modelling of Transition Metal Complexes: Structure). We have recently developed a QM/MM extension of a Car-Parrinello scheme [5]. These hybrid Car functional theory embedded in a classical force field description. The power of such a combined Car

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

    E-Print Network [OSTI]

    Suman Chakrabarty; Dwaipayan Chakrabarti; Biman Bagchi

    2006-03-14

    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.

  11. Towards a model of large scale dynamics in transitional wall-bounded flows

    E-Print Network [OSTI]

    Manneville, Paul

    2015-01-01

    A system of simplified equations is proposed to govern the feedback interactions of large-scale flows present in laminar-turbulent patterns of transitional wall-bounded flows, with small-scale Reynolds stresses generated by the self-sustainment process of turbulence itself modeled using an extension of Waleffe's approach (Phys. Fluids 9 (1997) 883-900), the detailed expression of which is displayed as an annex to the main text.

  12. April 30, 2013 Mathematical and Computer Modelling of Dynamical Systems criticalTransitions Mathematical and Computer Modelling of Dynamical Systems

    E-Print Network [OSTI]

    Gedeon, Tomas

    , from those appearing in physiology and ecology to Earth systems modeling, often experience critical

  13. Hierarchical Dynamic Models

    E-Print Network [OSTI]

    Penny, Will

    Hierarchical Dynamic Models Will Penny OU Processes Embedding OU(2) process Dynamic Models Hierarchical Dynamic Models Will Penny 26th May 2011 #12;Hierarchical Dynamic Models Will Penny OU Processes Dynamic Models Will Penny OU Processes Embedding OU(2) process Dynamic Models Generalised coordinates

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

    E-Print Network [OSTI]

    Supple, Derek R. (Derek Richard)

    2007-01-01

    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 ...

  15. Dynamics of stimulated L ? H transitions

    SciTech Connect (OSTI)

    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)

    2013-08-15

    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.

  16. Microgravity Flow Regime Transition Modeling 

    E-Print Network [OSTI]

    Shephard, Adam M.

    2010-07-14

    Flow regime transitions and the modeling thereof underlie the design of microgravity two-phase systems. Through the use of the zero-g laboratory, microgravity two-phase flows can be studied. Because microgravity two-phase flows exhibit essentially...

  17. The Dynamic Transition of Protein Hydration Water

    E-Print Network [OSTI]

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

    2010-02-12

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

  18. Distributed Algorithms with Dynamical Random Transitions

    E-Print Network [OSTI]

    Henri Poincaré -Nancy-Université, Université

    of the storage allocation system is taken as a function of time to be a #12;nite-state Markov chain resources where allocation and deal- location requests are dynamic random variables. This stochastic model, 16, 19]. The technique is applicable to other stochastically modelled resource allocation protocoles

  19. Water-Peptide Dynamics during Conformational Transitions Dmitry Nerukh*,

    E-Print Network [OSTI]

    Nerukh, Dmitry

    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

  20. Dynamic transitions of quasi-geostrophic channel flow.

    E-Print Network [OSTI]

    2015-09-21

    The main objective of this paper is to investigate the dynamic transition and the .... The quantity ? can be considered as a measure of the net mechanical energy.

  1. Continuous and discontinuous dynamic unbinding transitions in drawn film flow

    E-Print Network [OSTI]

    M. Galvagno; D. Tseluiko; H. Lopez; U. Thiele

    2013-11-27

    When a plate is withdrawn from a liquid bath a coating layer is deposited whose thickness and homogeneity depend on the velocity and the wetting properties of the plate. Using a long-wave mesoscopic hydrodynamic description that incorporates wettability via a Derjaguin (disjoining) pressure we identify four qualitatively different dynamic transitions between microscopic and macroscopic coatings that are out-of-equilibrium equivalents of well known equilibrium unbinding transitions. Namely, these are continuous and discontinuous dynamic emptying transitions and discontinuous and continuous dynamic wetting transitions. We uncover several features that have no equivalent at equilibrium.

  2. Dynamic Phase Transition, Enhanced Reaction Rate, and

    E-Print Network [OSTI]

    Rikvold, Per Arne

    is a CO, they react [CO + O CO2(g)] These dynamical rules fully define the model. Its properties on a crystal surface by Langmuir-Hinshelwood mechanism: CO(g)+S CO(a) O2 + 2S 2O(a) CO(a) + O(a) CO2(g) + 2S been observed experimentally for high enough temperatures. Add CO desorption rate k to mimic

  3. Protein viscoelastic dynamics: a model system

    E-Print Network [OSTI]

    Craig Fogle; Joseph Rudnick; David Jasnow

    2015-02-02

    A model system inspired by recent experiments on the dynamics of a folded protein under the influence of a sinusoidal force is investigated and found to replicate many of the response characteristics of such a system. The essence of the model is a strongly over-damped oscillator described by a harmonic restoring force for small displacements that reversibly yields to stress under sufficiently large displacement. This simple dynamical system also reveals unexpectedly rich behavior, exhibiting a series of dynamical transitions and analogies with equilibrium thermodynamic phase transitions. The effects of noise and of inertia are briefly considered and described.

  4. Dynamic Analysis of Fuel Cycle Transitioning

    SciTech Connect (OSTI)

    Brent Dixon; Steve Piet; David Shropshire; Gretchen Matthern

    2009-09-01

    This paper examines the time-dependent dynamics of transitioning from a once-through fuel cycle to a closed fuel cycle. The once-through system involves only Light Water Reactors (LWRs) operating on uranium oxide fuel UOX), while the closed cycle includes both LWRs and fast spectrum reactors (FRs) in either a single-tier system or two-tier fuel system. The single-tier system includes full transuranic recycle in FRs while the two-tier system adds one pass of mixed oxide uranium-plutonium (MOX U-Pu) fuel in the LWR. While the analysis primarily focuses on burner fast reactors, transuranic conversion ratios up to 1.0 are assessed and many of the findings apply to any fuel cycle transitioning from a thermal once-through system to a synergistic thermal-fast recycle system. These findings include uranium requirements for a range of nuclear electricity growth rates, the importance of back end fuel cycle facility timing and magnitude, the impact of employing a range of fast reactor conversion ratios, system sensitivity to used fuel cooling time prior to recycle, impacts on a range of waste management indicators, and projected electricity cost ranges for once-through, single-tier and two-tier systems. The study confirmed that significant waste management benefits can be realized as soon as recycling is initiated, but natural uranium savings are minimal in this century. The use of MOX in LWRs decouples the development of recycle facilities from fast reactor fielding, but also significantly delays and limits fast reactor deployment. In all cases, fast reactor deployment was significantly below than predicted by static equilibrium analyses.

  5. THE DYNAMICAL INFLUENCES FROM PHYSICAL PROPERTIES IN THE LOWER MANTLE AND POST-PEROVSKITE PHASE TRANSITION

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    1 THE DYNAMICAL INFLUENCES FROM PHYSICAL PROPERTIES IN THE LOWER MANTLE AND POST-PEROVSKITE PHASE, Yokohama 236-0001, Japan ABSTRACT The discovery of post-perovskite phase transition near the core conductivity together with the post-perovskite transition within the framework of isochemical models We have

  6. Dynamic cable analysis models

    SciTech Connect (OSTI)

    Palo, P.A.; Meggitt, D.J.; Nordell, W.J.

    1983-05-01

    This paper presents a summary of the development and validation of undersea cable dynamics computer models by the Naval Civil Engineering Laboratory (NCEL) under the sponsorship of the Naval Facilities Engineering Command. These models allow for the analysis of both small displacement (strumming) and large displacement (static and dynamic) deformations of arbitrarily configured cable structures. All of the large displacement models described in this paper are available to the public. This paper does not emphasize the theoretical development of the models (this information is available in other references) but emphasizes the various features of the models, the comparisons between model output and experimental data, and applications for which the models have been used.

  7. Calorimetric glass transition explained by hierarchical dynamic facilitation

    E-Print Network [OSTI]

    Garrahan, Juan P.

    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

  8. Direct Molecular Dynamics Observation of Protein Folding Transition State Ensemble

    E-Print Network [OSTI]

    Stanley, H. Eugene

    Direct Molecular Dynamics Observation of Protein Folding Transition State Ensemble Feng Ding for the interpretation of experimental results and understanding of protein folding mechanics, which has at- tracted, 1999; Guerois and Serrano, 2000) have been proposed to predict the transition states in protein folding

  9. Geometrical Dynamics in a Transitioning Superconducting Sphere

    E-Print Network [OSTI]

    James R. Claycomb; Rambis K. Chu

    2006-02-22

    Recent theoretical work has concentrated on calculating the Casimir effect in curved spacetime. In this paper we outline the forward problem of metrical variation due to the Casimir effect for spherical geometries. We consider a scalar quantum field inside a hollow superconducting sphere. Metric equations are developed describing the evolution of the scalar curvature after the sphere transitions to the normal state.

  10. Vehicle Modeling and Verification of CNG-Powered Transit Buses

    E-Print Network [OSTI]

    Hedrick, J. K.; Ni, A.

    2004-01-01

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

  11. Integrated Market Modeling of Hydrogen Transition Scenarios with...

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

    Integrated Market Modeling of Hydrogen Transition Scenarios with HyTrans Integrated Market Modeling of Hydrogen Transition Scenarios with HyTrans Presentation by Paul Leiby of Oak...

  12. The Quantum-Classical Transition in Nonlinear Dynamical Systems

    E-Print Network [OSTI]

    Salman Habib; Kurt Jacobs; Hideo Mabuchi; Robert Ryne; Kosuke Shizume; Bala Sundaram

    2000-10-26

    Viewed as approximations to quantum mechanics, classical evolutions can violate the positive-semidefiniteness of the density matrix. The nature of this violation suggests a classification of dynamical systems based on classical-quantum correspondence; we show that this can be used to identify when environmental interaction (decoherence) will be unsuccessful in inducing the quantum-classical transition. In particular, the late-time Wigner function can become positive without any corresponding approach to classical dynamics. In the light of these results, we emphasize key issues relevant for experiments studying the quantum-classical transition.

  13. Tools for dynamic model development

    E-Print Network [OSTI]

    Schaber, Spencer Daniel

    2014-01-01

    For this thesis, several tools for dynamic model development were developed and analyzed. Dynamic models can be used to simulate and optimize the behavior of a great number of natural and engineered systems, from the ...

  14. Quantum Phase Transition in a Graphene Model

    E-Print Network [OSTI]

    Simon Hands; Costas Strouthos

    2008-08-20

    We present results for the equation of state of a graphene-like model in an effort to understand the properties of its quantum phase transition. The N_f fermion species interact through a three dimensional instantaneous Coulomb potential. Since there are no reliable analytical tools that work for all values of N_f and the coupling constant g, we rely on Monte Carlo simulations to calculate the critical properties of the model near the phase transition. We consider the four-component formulation for the fermion fields, which arises naturally as the continuum limit of the staggered fermion construction in (2+1) dimensions. In the limit of infinitely strong Coulomb interaction, the system undergoes a quantum phase transition at a critical number of fermion species N_fc ~ 4.7. We also calculate the values of the critical exponents at the quantum phase transition.

  15. Dynamical thickening transition in plate coating with concentrated surfactant solutions

    E-Print Network [OSTI]

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

    2011-06-10

    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.

  16. UNIVERSALITY OF PHASE TRANSITION DYNAMICS: TOPOLOGICAL DEFECTS FROM SYMMETRY BREAKING

    SciTech Connect (OSTI)

    Zurek, Wojciech H.; Del Campo, Adolfo

    2014-02-13

    In the course of a non-equilibrium continuous phase transition, the dynamics ceases to be adiabatic in the vicinity of the critical point as a result of the critical slowing down (the divergence of the relaxation time in the neighborhood of the critical point). This enforces a local choice of the broken symmetry and can lead to the formation of topological defects. The Kibble-Zurek mechanism (KZM) was developed to describe the associated nonequilibrium dynamics and to estimate the density of defects as a function of the quench rate through the transition. During recent years, several new experiments investigating formation of defects in phase transitions induced by a quench both in classical and quantum mechanical systems were carried out. At the same time, some established results were called into question. We review and analyze the Kibble-Zurek mechanism focusing in particular on this surge of activity, and suggest possible directions for further progress.

  17. Transitional solar dynamics, cosmic rays and global warming

    E-Print Network [OSTI]

    A. Bershadskii

    2009-04-12

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

  18. Evolution of dynamical facilitation approaching the granular glass transition

    E-Print Network [OSTI]

    R. Candelier; O. Dauchot; G. Biroli

    2009-12-02

    We investigate the relaxation dynamics of a dense monolayer of bidisperse beads by analyzing the experimental data previously obtained in a fluidized bed. We show that the dynamics is formed by elementary relaxation events called cage jumps. These aggregate on a very short time into clusters. Increasing the packing fraction makes the spatio-temporal organization of the clusters evolve from a rather scattered and random distribution towards a collection of sparse and large events, called avalanches. The avalanche process is a manifestation of dynamical facilitation. The study of its evolution with density reveals that dynamical facilitation becomes less conserved and play a lesser role for the structural relaxation approaching the granular glass transition.

  19. Transition Events in Butane Simulations Similarities Across Models

    E-Print Network [OSTI]

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

    2001-01-01

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

  20. From quantum to classical dynamics: Dynamic crossover in the relativistic $O(N)$ model

    E-Print Network [OSTI]

    Mesterházy, David; Tanizaki, Yuya

    2015-01-01

    We investigate the transition from quantum to classical dynamics in the relativistic $O(N)$ vector model using the nonperturbative functional renormalization group in the real-time formalism. In thermal equilibrium, the theory is characterized by two scales, the interaction range for coherent scattering of particles and the mean free path determined by the rate of incoherent collision with excitations in the thermal medium. Their competition determines the renormalization group flow and the effective dynamics of the model. Here we quantify the dynamic properties of the model in terms of the scale-dependent dynamic critical exponent $z$ for arbitrary temperatures and in $2 \\leq d \\leq 4$ spatial dimensions.

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

    E-Print Network [OSTI]

    Guido Tiana; Carlo Camilloni

    2012-07-05

    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.

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

    E-Print Network [OSTI]

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

    2007-03-22

    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.

  3. Identification of Transition-Based Models of Biological Systems using Logic Programming

    E-Print Network [OSTI]

    New South Wales, University of

    the identification of: pure Petri nets; extended Petri nets; networks that re-use sub-nets; network from data Sydney 2052, Australia #12;Abstract Transition systems like Petri nets have been widely used to model networks and to capture the dynamics of system behaviour. To date, these models have mostly been specified

  4. A NEW APPROACH TO MODELING LARGE-SCALE ALTERNATIVE FUEL AND VEHICLE TRANSITIONS

    E-Print Network [OSTI]

    Lin, C.-Y. Cynthia

    counter-intuitive dynamic: high energy prices can discourage wide scale adoption of alternative fueled 1 A NEW APPROACH TO MODELING LARGE-SCALE ALTERNATIVE FUEL AND VEHICLE TRANSITIONS by Joel to alternative fuels and vehicles will be challenging. New modeling approaches are necessary to supplement

  5. Dynamic models for nonstationary signal segmentation

    E-Print Network [OSTI]

    Penny, Will

    Dynamic models for nonstationary signal segmentation William D. Penny and Stephen J. Roberts w.penny

  6. Statistical mechanics model for the transit free energy of monatomic liquids

    E-Print Network [OSTI]

    Duane C. Wallace; Eric D. Chisolm; N. Bock; G. De Lorenzi-Venneri

    2010-04-19

    In applying Vibration-Transit (V-T) theory of liquid dynamics to the thermodynamic properties of monatomic liquids, the point has been reached where an improved model is needed for the small (approx. 10%) transit contribution. Toward this goal, an analysis of the available high-temperature experimental entropy data for elemental liquids was recently completed [D. C. Wallace, E. D. Chisolm, and N. Bock, Phys. Rev. B 79, 051201 (2009)]. This analysis yields a common curve of transit entropy vs. T/\\theta_{tr}, where T is temperature and \\theta_{tr} is a scaling temperature for each element. In the present paper, a statistical mechanics model is constructed for the transit partition function, and is calibrated to the experimental transit entropy curve. The model has two scalar parameters, and captures the temperature scaling of experiment. The calibrated model fits the experimental liquid entropy to high accuracy at all temperatures. With no additional parameters, the model also agrees with both experiment and molecular dynamics for the internal energy vs. T for Na. With the calibrated transit model, V-T theory provides equations subject to ab initio evaluation for thermodynamic properties of monatomic liquids. This will allow the range of applicability of the theory, and its overall accuracy, to be determined. More generally, the hypothesis of V-T theory, which divides the many-atom potential energy valleys into random and symmetric classes, can also be tested for its application beyond monatomic systems.

  7. Quantum speed-up transition in open system dynamics

    E-Print Network [OSTI]

    Xiang Hao; Wenjiong Wu

    2015-10-20

    The rate of the trace distance is used to evaluate quantum speed-up for arbitrary mixed states. Compared with some present methods, the approach based on trace distance can provide an optimal bound to the speed of the evolution. The dynamical transition from no speed-up region to speed-up region takes on in the spontaneous decay of an two-level atom with detuning. The evolution is characteristic of the alternating behavior between quantum speed-up and speed-down in the strong system-reservoir coupling regime. Under the o?ff-resonance condition, the dynamical evolution can be accelerated for short previous times and then decelerated to a normal process either in the weak or strong coupling regime. From the time-energy uncertainty relation, we demonstrate that the potential capacity for quantum speed-up evolution is closely related to the energy flow-back from the reservoir to the system. The negative decay rate for short time intervals leads to the speed-up process where the photons previously emitted by the atom are reabsorbed at a later time. The values of the spontaneous decay rate becomes positive after a long enough time, which results in the normal evolution with no speed-up potential.

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

    Open Energy Info (EERE)

    Pritchett, 2004) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness...

  9. Nonadiabatic transition state theory and multiple potential energy surface molecular dynamics of infrequent events

    E-Print Network [OSTI]

    Hammes-Schiffer, Sharon

    Nonadiabatic transition state theory and multiple potential energy surface molecular dynamics in the vicinity of the energy barrier, i.e., in the region of the transition state or bottleneck. In general, TST 07974 Received 7 July 1995; accepted 17 August 1995 Classical transition state theory TST provides

  10. Femtosecond Transition-State Dynamics of Dissociating OCS on the Excited 1+ Potential Energy Surface

    E-Print Network [OSTI]

    Liu, Shilin

    Femtosecond Transition-State Dynamics of Dissociating OCS on the Excited 1+ Potential Energy photodissociation dynamics of OCS on the dissociative potential energy surface (PES) of the electronically excited 1 calculations. The high-resolution PHOFEX spectrum of the entire 1+-1+ transition (63 300-69 350 cm-1

  11. DYNAMIC MODELING FUEL PROCESSORS

    E-Print Network [OSTI]

    Mease, Kenneth D.

    turbine module (compressor and turbine sub-modules) Catalytic oxidizer Combustor module Heat exchanger, PEM, Gas Turbine General Model Assumptions · 1D process flow · Well-stirred within nodal volume · Slow reactants #12;Steam Reformation ­ Occurs in Reformer and Fuel Cells Methane reformation reaction Water Gas

  12. Debye mass at the QCD transition in the PNJL model

    E-Print Network [OSTI]

    Jankowski, J; Kaczmarek, O

    2015-01-01

    We consider colour-electric screening as expressed by the quark contribution to the Debye mass calculated in a PNJL model with emphasis on confining and chiral symmetry breaking effects. We observe that the screening mass is entirely determined by the nonperturbative quark distribution function and temperature dependent QCD running coupling. The role of the gluon background (Polyakov loop) is to provide strong suppression of the number of charge carriers below the transition temperature, as an effect of confinement, while the temperature dependent dynamical quark mass contributes additional suppression, as an effect of chiral symmetry breaking. An alternative derivation of this result from a modified kinetic theory is given, which allows for a slight generalization and explicit contact with perturbative QCD. This gives the possibility to gain insights into the colour screening mechanism in the region near the QCD pseudocritical temperature and to provide a guideline for the interpretation of lattice QCD data.

  13. Modeling Blog Dynamics Michaela Gotz

    E-Print Network [OSTI]

    Leskovec, Jure

    Modeling Blog Dynamics Michaela G¨otz Cornell University goetz@cs.cornell.edu Jure Leskovec@cs.cmu.edu Christos Faloutsos Carnegie Mellon University christos@cs.cmu.edu Abstract How do blogs produce posts? What local, underlying mech- anisms lead to the bursty temporal behaviors observed in blog networks? Earlier

  14. MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION

    E-Print Network [OSTI]

    Faccanoni, Gloria

    . (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method. (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method Vapor = 0 x = 0 = 1Fictive fluid 0 pressure law

  15. Realization of the Dicke model using cavity-assisted Raman transitions

    E-Print Network [OSTI]

    Markus P. Baden; Kyle J. Arnold; Arne L. Grimsmo; Scott Parkins; Murray D. Barrett

    2014-07-11

    We realize an open version of the Dicke model by coupling two hyperfine ground states using two cavity-assisted Raman transitions. The interaction due to only one of the couplings is described by the Tavis-Cummings model and we observe a normal mode splitting in the transmission around the dispersively shifted cavity. With both couplings present the dynamics are described by the Dicke model and we measure the onset of superradiant scattering into the cavity above a critical coupling strength.

  16. AFDM: An Advanced Fluid-Dynamics Model

    SciTech Connect (OSTI)

    Bohl, W.R.; Parker, F.R. (Los Alamos National Lab., NM (USA)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Goutagny, L. (CEA Centre d'Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France). Inst. de Protection et de Surete Nucleaire); Ninokata,

    1990-09-01

    AFDM, or the Advanced Fluid-Dynamics Model, is a computer code that investigates new approaches simulating the multiphase-flow fluid-dynamics aspects of severe accidents in fast reactors. The AFDM formalism starts with differential equations similar to those in the SIMMER-II code. These equations are modified to treat three velocity fields and supplemented with a variety of new models. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, on the dominant liquid, and on the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow regimes are permitted for the pool situations modeled. Virtual mass terms are included for vapor in liquid-continuous flow. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas are also modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer is generally treated using engineering correlations. Liquid-vapor phase transitions are handled with the nonequilibrium, heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. Convection is treated using a fractional-step method of time integration, including a semi-implicit pressure iteration. A higher-order differencing option is provided to control numerical diffusion. The Los Alamos SESAME equation-of-state has been implemented using densities and temperatures as the independent variables. AFDM programming has vectorized all computational loops consistent with the objective of producing an exportable code. 24 refs., 4 figs.

  17. Dynamic migration of rotating neutron stars due to a phase transition instability

    E-Print Network [OSTI]

    Harald Dimmelmeier; Michal Bejger; Pawel Haensel; J. Leszek Zdunik

    2009-04-09

    Using numerical simulations based on solving the general relativistic hydrodynamic equations, we study the dynamics of a phase transition in the dense core of isolated rotating neutron stars, triggered by the back bending instability reached via angular momentum loss. In particular, we investigate the dynamics of a migration from an unstable configuration into a stable one, which leads to a mini-collapse of the neutron star and excites sizeable pulsations in its bulk until it acquires a new stable equilibrium state. We consider equations of state with softening at high densities, a simple analytic one with a mixed hadron-quark phase in an intermediate pressure interval and pure quark matter at very high densities, and a microphysical one that has a first-order phase transition, originating from kaon condensation. Although the marginally stable initial models are rigidly rotating, we observe that during the collapse (albeit little) differential rotation is created. We analyze the emission of gravitational radiation, which in some models is amplified by mode resonance effects, and assess its prospective detectability by interferometric detectors. We expect that the most favorable conditions for dynamic migration exist in very young magnetars. We find that the damping of the post-migration pulsations strongly depends on the character of the equation of state softening. The damping of pulsations in the models with the microphysical equation of state is caused by dissipation associated with matter flowing through the density jump at the edge of the dense core. If at work, this mechanism dominates over all other types of dissipation, like bulk viscosity in the exotic-phase core, gravitational radiation damping, or numerical viscosity.

  18. Identification of the protein folding transition state from molecular dynamics trajectories

    E-Print Network [OSTI]

    Caflisch, Amedeo

    Identification of the protein folding transition state from molecular dynamics trajectories S. Muff The rate of protein folding is governed by the transition state so that a detailed characterization of its. INTRODUCTION Proteins fold from the heterogeneous set of denatured conformations to the structurally well

  19. Euclidean Dynamical Triangulation revisited: is the phase transition really 1st order? (extended version)

    E-Print Network [OSTI]

    Tobias Rindlisbacher; Philippe de Forcrand

    2015-06-10

    The transition between the two phases of 4D Euclidean Dynamical Triangulation [1] was long believed to be of second order until in 1996 first order behavior was found for sufficiently large systems [5,9]. However, one may wonder if this finding was affected by the numerical methods used: to control volume fluctuations, in both studies [5,9] an artificial harmonic potential was added to the action; in [9] measurements were taken after a fixed number of accepted instead of attempted moves which introduces an additional error. Finally the simulations suffer from strong critical slowing down which may have been underestimated. In the present work, we address the above weaknesses: we allow the volume to fluctuate freely within a fixed interval; we take measurements after a fixed number of attempted moves; and we overcome critical slowing down by using an optimized parallel tempering algorithm [12]. With these improved methods, on systems of size up to 64k 4-simplices, we confirm that the phase transition is first order. In addition, we discuss a local criterion to decide whether parts of a triangulation are in the elongated or crumpled state and describe a new correspondence between EDT and the balls in boxes model. The latter gives rise to a modified partition function with an additional, third coupling. Finally, we propose and motivate a class of modified path-integral measures that might remove the metastability of the Markov chain and turn the phase transition into second order.

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

    SciTech Connect (OSTI)

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

    2011-11-11

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

  1. Effects of Phase Transition induced density fluctuations on pulsar dynamics

    E-Print Network [OSTI]

    Bagchi, Partha; Layek, Biswanath; Srivastava, Ajit M

    2015-01-01

    We show that density fluctuations during phase transitions in pulsar cores may have non-trivial effects on pulsar timings, and may also possibly account for glitches and anti-glitches. These density fluctuations invariably lead to non-zero off-diagonal components of the moment of inertia, leading to transient wobbling of star. Thus, accurate measurements of pulsar timing and intensity modulations (from wobbling) may be used to identify the specific pattern of density fluctuations, hence the particular phase transition, occurring inside the pulsar core. Changes in quadrupole moment from rapidly evolving density fluctuations during the transition, with very short time scales, may provide a new source for gravitational waves.

  2. A Relativistic Dynamical Collapse Model

    E-Print Network [OSTI]

    Philip Pearle

    2014-12-21

    A model is discussed where all operators are constructed from a quantum scalar field whose energy spectrum takes on all real values. The Schr\\"odinger picture wave function depends upon space and time coordinates for each particle, as well as an inexorably increasing evolution parameter $s$ which labels a foliation of space-like hypersurfaces. The model is constructed to be manifestly Lorentz invariant in the interaction picture. Free particle states and interactions are discussed in this framework. Then, the formalism of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied. The collapse-generating operator is chosen to to be the particle number space-time density. Unlike previous relativistically invariant models, the vacuum state is not excited. The collapse dynamics depends upon two parameters, a parameter $\\Lambda$ which represents the collapse rate/volume and a scale factor $\\ell$. A common example of collapse dynamics, involving a clump of matter in a superposition of two locations, is analyzed. The collapse rate is shown to be identical to that of non-relativistic CSL when the GRW-CSL choice of $\\ell=a=10^{-5}$cm, is made, along with $\\Lambda=\\lambda/a^{3}$ (GRW-CSL choice $\\lambda=10^{-16}s^{-1}$). However, it is also shown that the change of mass of a nucleon over the age of the universe is then unacceptably large. The case where $\\ell$ is the size of the universe is then considered. It is shown that the collapse behavior is satisfactory and the change of mass over the age of the universe is acceptably small, when $\\Lambda= \\lambda/\\ell a^{2}$.

  3. Hydrogen Transition (HyTRANS) Model

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Financing Tool Fits the Bill FinancingDepartmentDatabase Demonstration HydrogenClean CoalTransition

  4. Process Model Discovery: A Method Based on Transition System Decomposition

    E-Print Network [OSTI]

    van der Aalst, Wil

    Process Model Discovery: A Method Based on Transition System Decomposition Anna A. Kalenkova1 discovery algo- rithms deal with large data sets to learn automatically process models. As more event data by the unified process model. The proposed discovery algorithm is illustrated using a running example. 1

  5. Development of one-equation transition/turbulence models

    SciTech Connect (OSTI)

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

    2000-01-14

    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.

  6. An intelligent floor field cellular automata model for pedestrian dynamics

    E-Print Network [OSTI]

    Ekaterina Kirik; Tat'yana Yurgel'yan; Dmitriy Krouglov

    2009-06-15

    A stochastic cellular automata (CA) model for pedestrian dynamics is presented. Our goal is to simulate different types of pedestrian movement, from regular to panic. But here we emphasize regular situations which imply that pedestrians analyze environment and choose their route more carefully. And transition probabilities have to depict such effect. The potentials of floor fields and environment analysis are combined in the model obtained. People patience is included in the model. This makes simulation of pedestrians movement more realistic. Some simulation results are presented and comparison with basic FF-model is made.

  7. Comparison of the structural and orientational glass-transition dynamics in ethanol M. A. Miller

    E-Print Network [OSTI]

    Birge, Norman

    Comparison of the structural and orientational glass-transition dynamics in ethanol M. A. Miller 1997 The dynamics of the supercooled-liquid and rotator-phase crystal of the same material, ethanol that ethanol (C2H5OH) exhibits interesting phase polymorphism, and ap- pears to be quite unique in that it can

  8. AFDM: An Advanced Fluid-Dynamics Model

    SciTech Connect (OSTI)

    Berthier, J. (CEA Centre d'Etudes Nucleaires de Grenoble, 38 (France)); Wilhelm, D. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik); Bohl, W.R. (Los Alamos National Lab., NM (USA))

    1990-09-01

    This report consists of three parts. First, for the standard Advanced Fluid-Dynamics Model (AFDM), heat-transfer coefficients between components are worked out, depending on the different possible topologies. Conduction, convection, and radiative heat-transfer mechanisms are modeled. For solid particles, discontinuous phases that obey a rigid'' model, and components lacking relative motion, heat transfer is by conduction. Convection is represented for fluids in motion inside circulating'' bubbles and/or droplets. Radiation is considered between droplets in vapor continuous flow. In addition, a film-boiling model has been formulated, where radiation provides the lower limit on the fuel-to-coolant heat-transfer coefficient. Second, the momentum-exchange coefficients are defined for the standard AFDM. Between a continuous and discontinuous phase, the model consists of both laminar and turbulent terms. The most important feature is the drag coefficient in the turbulent term. It is calculated by a drag similarity hypothesis with limits for large Reynolds numbers, distorted particles,'' and churn-turbulent flow. A unique hysteresis algorithm exists to treat the liquid continuous to vapor continuous transition. Two discontinuous components are coupled using a turbulent term with an input drag coefficient. Fluid- structure momentum exchange is represented with a standard friction-factor correlation. Third, the formulas used for the AFDM simplified Step 1 models are discussed. These include the heat-transfer coefficients, the momentum-exchange functions, and the manner in which interfacial areas are determined from input length scales. The simplified modeling uses steady-state engineering correlations, as in SIMMER-II.

  9. Dynamical modeling of tidal streams

    SciTech Connect (OSTI)

    Bovy, Jo, E-mail: bovy@ias.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

    2014-11-01

    I present a new framework for modeling the dynamics of tidal streams. The framework consists of simple models for the initial action-angle distribution of tidal debris, which can be straightforwardly evolved forward in time. Taking advantage of the essentially one-dimensional nature of tidal streams, the transformation to position-velocity coordinates can be linearized and interpolated near a small number of points along the stream, thus allowing for efficient computations of a stream's properties in observable quantities. I illustrate how to calculate the stream's average location (its 'track') in different coordinate systems, how to quickly estimate the dispersion around its track, and how to draw mock stream data. As a generative model, this framework allows one to compute the full probability distribution function and marginalize over or condition it on certain phase-space dimensions as well as convolve it with observational uncertainties. This will be instrumental in proper data analysis of stream data. In addition to providing a computationally efficient practical tool for modeling the dynamics of tidal streams, the action-angle nature of the framework helps elucidate how the observed width of the stream relates to the velocity dispersion or mass of the progenitor, and how the progenitors of 'orphan' streams could be located. The practical usefulness of the proposed framework crucially depends on the ability to calculate action-angle variables for any orbit in any gravitational potential. A novel method for calculating actions, frequencies, and angles in any static potential using a single orbit integration is described in the Appendix.

  10. Quantum phase transitions in transverse field spin models: from statistical physics to quantum information

    E-Print Network [OSTI]

    Amit Dutta; Gabriel Aeppli; Bikas K. Chakrabarti; Uma Divakaran; Thomas F. Rosenbaum; Diptiman Sen

    2015-06-09

    We review quantum phase transitions of spin systems in transverse magnetic fields taking the examples of the spin-1/2 Ising and XY models in a transverse field. Beginning with an overview of quantum phase transitions, we introduce a number of model Hamiltonians. We provide exact solutions in one spatial dimension connecting them to conformal field theoretical studies. We also discuss Kitaev models and some other exactly solvable spin systems. Studies of quantum phase transitions in the presence of quenched randomness and with frustrating interactions are presented in detail. We discuss novel phenomena like Griffiths-McCoy singularities. We then turn to more recent topics like information theoretic measures of the quantum phase transitions in these models such as concurrence, entanglement entropy, quantum discord and quantum fidelity. We then focus on non-equilibrium dynamics of a variety of transverse field systems across quantum critical points and lines. After mentioning rapid quenching studies, we dwell on slow dynamics and discuss the Kibble-Zurek scaling for the defect density following a quench across critical points and its modifications for quenching across critical lines, gapless regions and multicritical points. Topics like the role of different quenching schemes, local quenching, quenching of models with random interactions and quenching of a spin chain coupled to a heat bath are touched upon. The connection between non-equilibrium dynamics and quantum information theoretic measures is presented at some length. We indicate the connection between Kibble-Zurek scaling and adiabatic evolution of a state as well as the application of adiabatic dynamics as a tool of a quantum optimization technique known as quantum annealing. The final section is dedicated to a detailed discussion on recent experimental studies of transverse Ising-like systems.

  11. A general holographic metal/superconductor phase transition model

    E-Print Network [OSTI]

    Yan Peng; Yunqi Liu

    2015-03-03

    We study the scalar condensation of a general holographic superconductor model in AdS black hole background away from the probe limit. We find the model parameters together with the scalar mass and backreaction can determine the order of phase transitions completely. In addition, we observe two types of discontinuities of the scalar operator in the case of first order phase transitions. We analyze in detail the effects of the scalar mass and backreaction on the formation of discontinuities and arrive at an approximate relation between the threshold model parameters. Furthermore, we obtain superconductor solutions corresponding to higher energy states and examine the stability of these superconductor solutions.

  12. Modelling and Dynamic Simulation for Process Control

    E-Print Network [OSTI]

    Skogestad, Sigurd

    principles for model development are outlined, and these principles are applied to a simple ash tank (which. In this paper we consider dynamic process models obtained using fundamental principles (eg. based reactor, a simple trend analysis using temperature measurements may be suÆcient. Dynamic models

  13. GENERATION OF TRANSITION CLASS MODELS FROM FORMAL QUEUEING NETWORK DESCRIPTIONS

    E-Print Network [OSTI]

    Strelen, Christoph

    stochastic Petri nets (GSPN), UltraSAN [8] for stochastic activity networks, a class of stochastic Petri netsGENERATION OF TRANSITION CLASS MODELS FROM FORMAL QUEUEING NETWORK DESCRIPTIONS Johann Christoph-mail: strelen@cs.uni-bonn.de KEYWORDS Queueing Networks, Tools, Multi-Paradigm Models, Gener- ation, Markov

  14. Chaotic Dynamics in Multidimensional Transition States Ali Allahem1, a)

    E-Print Network [OSTI]

    , not in configuration space. It is bounded by a high-dimensional invariant hyper-sphere that plays the role of the periodic orbit in the two-dimensional setting. At sufficiently low energies, this hyper geometric objects in phase space: An invariant hyper-sphere that represents the transition state itself

  15. Quantitative Modeling of High Temperature Magnetization Dynamics

    SciTech Connect (OSTI)

    Zhang, Shufeng

    2009-03-01

    Final Technical Report Project title: Quantitative Modeling of High Temperature Magnetization Dynamics DOE/Office of Science Program Manager Contact: Dr. James Davenport

  16. Emerging attractors and the transition from dissipative to conservative dynamics

    E-Print Network [OSTI]

    Christian S. Rodrigues; Alessandro P. S. de Moura; Celso Grebogi

    2009-07-17

    The topological structure of basin boundaries plays a fundamental role in the sensitivity to the initial conditions in chaotic dynamical systems. Herewith we present a study on the dynamics of dissipative systems close to the Hamiltonian limit, emphasising the increasing number of periodic attractors and on the structural changes in their basin boundaries as the dissipation approaches zero. We show numerically that a power law with nontrivial exponent describes the growth of the total number of periodic attractors as the damping is decreased. We also establish that for small scales the dynamics is governed by \\emph{effective} dynamical invariants, whose measure depends not only on the region of the phase space, but also on the scale under consideration. Therefore, our results show that the concept of effective invariants is also relevant for dissipative systems.

  17. Temperature dependent transport coefficients in a dynamical holographic QCD model

    E-Print Network [OSTI]

    Danning Li; Song He; Mei Huang

    2014-11-19

    We investigate temperature dependent behavior of various transport coefficients in a dynamical holographical QCD model. We show the nontrivial temperature dependent behavior of the transport coefficients, like bulk viscosity, electric conductivity as well as jet quenching parameter, and it is found that all these quantities reveal information of the phase transition. Furthermore, with introducing higher derivative corrections in 5D gravity, the shear viscosity over entropy density ratio also shows a valley around phase transition, and it is found that the shear viscosity over entropy density ratio times the jet quenching over temperature cubic ratio almost remains as a constant above phase transition, and the value is two times larger than the perturbative result in Phys.Rev.Lett.99.192301(2007).

  18. Conceptual aircraft dynamics from inverse aircraft modeling 

    E-Print Network [OSTI]

    Ziegler, Gregory E

    1999-01-01

    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...

  19. Elastic models of the glass transition applied to a liquid with density anomalies

    E-Print Network [OSTI]

    M. Pica Ciamarra; Peter Sollich

    2015-08-19

    Elastic models of the glass transition relate the relaxation dynamics and the elastic properties of structural glasses. They are based on the assumption that the relaxation dynamics occurs through activated events in the energy landscape whose energy scale is set by the elasticity of the material. Here we investigate whether such elastic models describe the relaxation dynamics of systems of particles interacting via a purely repulsive harmonic potential, focusing on a volume fraction and temperature range that is characterized by entropy--driven water--like density anomalies. We do find clear correlations between relaxation time and diffusivity on the one hand, and plateau shear modulus and Debye--Waller factor on the other, thus supporting the validity of elastic models of the glass transition. However, we also show that the plateau shear modulus is not related to the features of the underlying energy landscape of the system, at variance with recent results for power--law potentials. This challenges the common potential energy landscape interpretation of elastic models.

  20. The dynamics of transition to turbulence in plane Couette flow

    E-Print Network [OSTI]

    Viswanath, D

    2007-01-01

    In plane Couette flow, the incompressible fluid between two plane parallel walls is driven by the motion of those walls. The laminar solution, in which the streamwise velocity varies linearly in the wall-normal direction, is known to be linearly stable at all Reynolds numbers ($Re$). Yet, in both experiments and computations, turbulence is observed for $Re \\gtrsim 360$. In this article, we show that when the laminar flow is perturbed on to the transition {\\it threshold}, the flow approaches either steady or traveling wave solutions. These solutions exhibit some aspects of turbulence but are not fully turbulent even at $Re=4000$. However, these solutions are linearly unstable and flows that evolve along their unstable directions become fully turbulent. The solution approached by a threshold perturbation depends upon the nature of the perturbation. Surprisingly, the positive eigenvalue that corresponds to one family of solutions decreases in magnitude with increasing $Re$, with the rate of decrease given by $Re...

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

    E-Print Network [OSTI]

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

    2008-01-05

    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.

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

    E-Print Network [OSTI]

    Maruyama, Shigeo

    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

  3. S0S1 transition of trans--methyl styrene: Vibronic structure and dynamics

    E-Print Network [OSTI]

    Haas, Yehuda

    S0S1 transition of trans- -methyl styrene: Vibronic structure and dynamics Y. Haas, S. Kendler, E; accepted 28 March 1995 The fluorescence excitation and emission spectra of trans- -methyl styrene have been of styrene and of trans- -methyl styrene BMS is reported. The BMS molecule is calculated to be essentially

  4. PHYSICAL REVIEW E 84, 061134 (2011) Entrainment of a driven oscillator as a dynamical phase transition

    E-Print Network [OSTI]

    Dinner, Aaron

    2011-01-01

    PHYSICAL REVIEW E 84, 061134 (2011) Entrainment of a driven oscillator as a dynamical phase, such as the glass transition. Here we use this approach to show that the entrainment of an oscillator to an external of eigenvalues for the unforced system. We find that in the entrainment region where the oscillator exhibits

  5. Development of a One-Equation Transition/Turbulence Model

    SciTech Connect (OSTI)

    EDWARDS,JACK R.; ROY,CHRISTOPHER J.; BLOTTNER,FREDERICK G.; HASSAN,HASSAN A.

    2000-09-26

    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 non-turbulent fluctuation growth based on that proposed by Warren and Hassan (Journal of Aircraft, Vol. 35, No. 5) is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittence function based on the work of Dhawan and Narasimha (Journal of Fluid Mechanics, Vol. 3, No. 4). 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 spatial accuracy of selected predictions is analyzed.

  6. Dynamics Modelling of Biolistic Gene Guns

    SciTech Connect (OSTI)

    Zhang, M.; Tao, W.; Pianetta, P.A.

    2009-06-04

    The gene transfer process using biolistic gene guns is a highly dynamic process. To achieve good performance, the process needs to be well understood and controlled. Unfortunately, no dynamic model is available in the open literature for analysing and controlling the process. This paper proposes such a model. Relationships of the penetration depth with the helium pressure, the penetration depth with the acceleration distance, and the penetration depth with the micro-carrier radius are presented. Simulations have also been conducted. The results agree well with experimental results in the open literature. The contribution of this paper includes a dynamic model for improving and manipulating performance of the biolistic gene gun.

  7. Simple Dynamic Gasifier Model That Runs in Aspen Dynamics

    SciTech Connect (OSTI)

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

    2008-10-15

    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.

  8. Modeling of Alpine Atmospheric Dynamics II

    E-Print Network [OSTI]

    Gohm, Alexander

    Modeling of Alpine Atmospheric Dynamics II 707.424, VU 2, SS2005 Unit 7: Model code structure: mesoscale convective system 17-18 April 2004: Sierra hydraulic jump case 21 January 2005: the "Universiade) Introduction (brief description of the phenomenon and a description of the model and of the measurements

  9. Dynamic modeling issues for power system applications 

    E-Print Network [OSTI]

    Song, Xuefeng

    2005-02-17

    Power system dynamics are commonly modeled by parameter dependent nonlinear differential-algebraic equations (DAE) x ???p y x f ) and 0 = p y x g ) . Due to (,, (,, the algebraic constraints, we cannot directly perform...

  10. Coherent structures in Dissipative Particle Dynamics simulations of the transition to turbulence in compressible shear flows

    E-Print Network [OSTI]

    van de Meent, Jan-Willem; Somfai, Ellak; Sultan, Eric; van Saarloos, Wim

    2008-01-01

    We present simulations of coherent structures in compressible flows near the transition to turbulence using the Dissipative Particle Dynamics (DPD) method. The structures we find are remarkably consistent with experimental observations and DNS simulations of incompressible flows, despite a difference in Mach number of several orders of magnitude. The bifurcation from the laminar flow is bistable and shifts to higher Reynolds numbers when the fluid becomes more compressible. This work underlines the robustness of coherent structures in the transition to turbulence and illustrates the ability of particle-based methods to reproduce complex non-linear instabilities.

  11. Dynamics of skyrmions in chiral magnets: Dynamic phase transitions and equation of motion

    SciTech Connect (OSTI)

    Lin, Shi-Zeng, E-mail: szl@lanl.gov; Reichhardt, Charles; Batista, Cristian D.; Saxena, Avadh [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-05-07

    We study the dynamics of skyrmions in a metallic chiral magnet. First, we show that skyrmions can be created dynamically by destabilizing the ferromagnetic background state through a spin polarized current. We then treat skyrmions as rigid particles and derive the corresponding equation of motion. The dynamics of skyrmions is dominated by the Magnus force, which accounts for the weak pinning of skyrmions observed in experiments. Finally, we discuss the quantum motion of skyrmions.

  12. A holographic model for antiferromagnetic quantum phase transition induced by magnetic field

    E-Print Network [OSTI]

    Rong-Gen Cai; Run-Qiu Yang; F. V. Kusmartsev

    2015-01-19

    We propose a gravity dual of antiferromagnetic quantum phase transition (QPT) induced by magnetic field and study the criticality in the vicinity of quantum critical point (QCP). Results show the boundary critical theory is a strong coupling theory with dynamic exponent $z=2$. The hyperscaling law is violated and logarithmic corrections appear near the QCP. We compare our theoretical results with experimental data on variety of materials including low-dimensional magnet, BiCoPO$_5$ and pyrochlores, Er$_{2-2x}$Y$_{2x}$Ti$_2$O$_7$. Our model describes well the existing experiments and predicts QCP and other high field magnetic properties of these compounds.

  13. Probing the quantum phase transition in the Dicke model through mechanical vibrations

    E-Print Network [OSTI]

    J. P. Santos; K. Furuya; F. L. Semião

    2011-03-04

    This paper is concerned with quantum dynamics of a system coupled to a critical reservoir. In this context, we employ the Dicke model which is known to exhibit a super radiant quantum phase transition (QPT) and we allow one of the mirrors to move under a linear restoring force. The electromagnetic field couples to the movable mirror though radiation pressure just like in typical optomechanical setups. We show that, in the thermodynamical limit, the super-radiant phase induces a classical driving force on the mirror without causing decoherence.

  14. Stochastic storage models and noise-induced phase transitions

    E-Print Network [OSTI]

    Serge Shpyrko; V. V. Ryazanov

    2007-01-13

    The most frequently used in physical application diffusive (based on the Fokker-Planck equation) model leans upon the assumption of small jumps of a macroscopic variable for each given realization of the stochastic process. This imposes restrictions on the description of the phase transition problem where the system is to overcome some finite potential barrier, or systems with finite size where the fluctuations are comparable with the size of a system. We suggest a complementary stochastic description of physical systems based on the mathematical stochastic storage model with basic notions of random input and output into a system. It reproduces statistical distributions typical for noise-induced phase transitions (e.g. Verhulst model) for the simplest (up to linear) forms of the escape function. We consider a generalization of the stochastic model based on the series development of the kinetic potential. On the contrast to Gaussian processes in which the development in series over a small parameter characterizing the jump value is assumed [Stratonovich R.L., Nonlinear Nonequilibrium Thermodynamics, Springer Series in Synergetics, vol.59, Springer Verlag, 1994], we propose a series expansion directly suitable for storage models and introduce the kinetic potential generalizing them.

  15. Role of entropy in the thermodynamic evolution of the time scale of molecular dynamics near the glass transition

    E-Print Network [OSTI]

    K. Grzybowska; A. Grzybowski; S. Pawlus; J. Pionteck; M. Paluch

    2014-10-23

    In this Letter, we investigate how changes in the system entropy influence the characteristic time scale of the system molecular dynamics near the glass transition. Independently of any model of thermodynamic evolution of the time scale, against some previous suppositions, we show that the system entropy $S$ is not sufficient to govern the time scale defined by structural relaxation time $\\tau $. In the density scaling regime, we argue that the decoupling between $\\tau $ and $S$ is a consequence of different values of the scaling exponents $\\gamma $ and $\\gamma_S $ in the density scaling laws, $\\tau = f(\\rho ^\\gamma /T)$ and $S = h(\\rho ^{\\gamma_S}/T)$, where $\\rho $ and $T$ denote density and temperature, respectively. It implies that the proper relation between $\\tau $ and $S$ requires supplementing with a density factor, $u(\\rho)$, i.e.,$\\tau = g(u(\\rho)w(S))$. This meaningful finding additionally demonstrates that the density scaling idea can be successfully used to separate physically relevant contributions to the time scale of molecular dynamics near the glass transition. As an example, we revise the Avramov entropic model of the dependence $\\tau (T,\\rho)$, giving evidence that its entropic basis has to be extended by the density dependence of the maximal energy barrier for structural relaxation. We also discuss the excess entropy $S_{ex}$, the density scaling of which is found to mimic the density scaling of the total system entropy $S$.

  16. Consistent nonlinear dynamics: identifying model inadequacy

    E-Print Network [OSTI]

    Patrick E. McSharry; Leonard A. Smith

    2004-03-09

    Empirical modelling often aims for the simplest model consistent with the data. A new technique is presented which quantifies the consistency of the model dynamics as a function of location in state space. As is well-known, traditional statistics of nonlinear models like root-mean-square (RMS) forecast error can prove misleading. Testing consistency is shown to overcome some of the deficiencies of RMS error, both within the perfect model scenario and when applied to data from several physical systems using previously published models. In particular, testing for consistent nonlinear dynamics provides insight towards (i) identifying when a delay reconstruction fails to be an embedding, (ii) allowing state dependent model selection and (iii) optimising local neighbourhood size. It also provides a more relevant (state dependent) threshold for identifying false nearest neighbours.

  17. Bayesian Nonparametric Inference of Switching Dynamic Linear Models

    E-Print Network [OSTI]

    Fox, Emily Beth

    Many complex dynamical phenomena can be effectively modeled by a system that switches among a set of conditionally linear dynamical modes. We consider two such models: the switching linear dynamical system (SLDS) and the ...

  18. Modeling the Dynamics of Fermentation and Respiratory

    E-Print Network [OSTI]

    Sheffield, University of

    Modeling the Dynamics of Fermentation and Respiratory Processes in a Groundwater Plume of Phenolic implemented into a field- scale reactive transport model of a groundwater plume of phenolic contaminants toxicity toward degradation, bioavailability of mineral oxides, and adsorption of biogenic Fe(II) species

  19. Six Degree of Freedom Morphing Aircraft Dynamical Model with Aerodynamics 

    E-Print Network [OSTI]

    Niksch, Adam

    2010-01-14

    model of a morphing aircraft is needed. This paper develops an aerodynamic model and a dynamic model of a morphing flying wing aircraft. The dynamic model includes realistic aerodynamic forces, consisting of lift, drag, and pitching moment about...

  20. Model for Aggregated Water Heater Load Using Dynamic Bayesian Networks

    SciTech Connect (OSTI)

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

    2012-07-19

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

  1. Analytical modeling of balloon launch dynamics 

    E-Print Network [OSTI]

    Strganac, Thomas W

    1980-01-01

    aerodynam1cs. Actual fl1ght data has been used to qualify the model via comparisons of the launch trans1ent configurations. DEDICATION To my father. . THOMAS JOHN STRGANAC 1922-1980 . . . who provided me the examp1e to fo1Iow in life. ACKNOWLEDGEMENTS... OF TABLES. LIST OF FIGURES NOMENCLATURE. INTRODUCTION. PRESENT STATUS. DYNAMIC MODEL Forces on the Balloon. Buoyancy . Weight Distribution. Catenary . Bubble Aerodynamics, Equations of Motion. Kutta-Simpson Solution Technique NUMERICAL MODEL...

  2. Spatio-temporal Bounded Noises, and transitions induced by them in solutions of real Ginzburg-Landau model

    E-Print Network [OSTI]

    Sebastiano de Franciscis; Alberto d'Onofrio

    2012-05-23

    In this work, we introduce two spatio-temporal colored bounded noises, based on the zero-dimensional Cai-Lin and Tsallis-Borland noises. We then study and characterize the dependence of the defined bounded noises on both a temporal correlation parameter $\\tau$ and on a spatial coupling parameter $\\lambda$. The boundedness of these noises has some consequences on their equilibrium distributions. Indeed in some cases varying $\\lambda$ may induce a transition of the distribution of the noise from bimodality to unimodality. With the aim to study the role played by bounded noises on nonlinear dynamical systems, we investigate the behavior of the real Ginzburg-Landau time-varying model additively perturbed by such noises. The observed phase transitions phenomenology is quite different from the one observed when the perturbations are unbounded. In particular, we observed an inverse "order-to-disorder" transition, and a re-entrant transition, with dependence on the specific type of bounded noise.

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

    SciTech Connect (OSTI)

    Khorrami, Mohammad Aghamohammadi, Amir

    2014-03-15

    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.

  4. Hysteretic transitions in the Kuramoto model with inertia

    E-Print Network [OSTI]

    Simona Olmi; Adrian Navas; Stefano Boccaletti; Alessandro Torcini

    2014-08-11

    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.

  5. Frequency Dependence Modulus of Pd??Ni??Cu??P?? Amorphous Alloy around the Glass Transition by Dynamic Mechanical Analysis

    E-Print Network [OSTI]

    Lee, M.L.

    Dynamic Mechanical Analyzer (DMA) was used to study the frequency dependence of storage and loss modulus of amorphous Pd??Ni??Cu??P?? alloy over a broad frequency range around its glass transition temperature. The amorphous ...

  6. A numerical study of longtime dynamics and ergodic-nonergodic transitions in dense simple fluids

    E-Print Network [OSTI]

    David D. McCowan

    2014-11-04

    For over 30 years, mode-coupling theory (MCT) has been the de facto theoretic description of dense fluids and the liquid-glass transition. MCT, however, is limited by its ad hoc construction and lacks a mechanism to institute corrections. We use recent results from a new theoretical framework--developed from first principles via a self-consistent perturbation expansion in terms of an effective two-body potential--to numerically explore the kinetics of systems of classical particles, specifically hard spheres obeying Smoluchowski dynamics. We present here a full solution to the kinetic equation governing the density-density time correlation function and show that the function exhibits the characteristic two-step decay of supercooled fluids and an ergodic-nonergodic transition to a dynamically-arrested state. Unlike many previous numerical studies and experiments, we have access to the full time and wavenumber range of the correlation function and can track the solution unprecedentedly close to the transition, covering nearly 15 decades of time. Using asymptotic approximation techniques developed for MCT, we fit the solution to predicted forms and extract critical parameters. Our solution shows a transition at packing fraction $\\eta^*=0.60149761(10)$--consistent with previous static solutions under this theory and with comparable colloidal suspension experiments--and the behavior in the $\\beta$-relaxation regime is fit to power-law decays with critical exponents $a=0.375(3)$ and $b=0.8887(4)$, and with $\\lambda=0.5587(18)$. For the $\\alpha$-relaxation of the ergodic phase, we find a power-law divergence of the time scale $\\tau_{\\alpha}$ as we approach the transition. Through these results, we establish that this new theory is able to reproduce the salient features of MCT, but has the advantages of a first principles derivation and a clear mechanism for making systematic improvements.

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

    E-Print Network [OSTI]

    de Gispert, Adrià

    A molecular dynamics simulation of the melting points and glass transition temperatures of myo transition temperature are calculated for myo- and neo-inositol, using the condensed-phase optimized temperatures for myo- and neo-inositol also compare very well to the experimentally obtained data. The glass

  8. The use of molecular dynamics for the thermodynamic properties of simple and transition metals

    SciTech Connect (OSTI)

    Straub, G.K.

    1987-04-01

    The technique of computer simulation of the molecular dynamics in metallic systems to calculate thermodynamic properties is discussed. The nature of a metal as determined by its electronic structure is used to determine the total adiabatic potential. The effective screened ion-ion interaction can then be used in a molecular dynamics simulation. The method for the construction of a molecular dynamics ensemble, its relation to the canonical ensemble, and the definition of thermodynamic functions from the Helmholtz free energy is given. The method for the analysis of the molecular dynamics results from quasiharmonic lattice dynamics and the decomposition in terms of harmonic and anharmonic contributions is given for solids. For fluid phase metals, procedures for calculating the thermodynamics and determining the constant of entropy are presented. The solid-fluid phase boundary as a function of pressure and temperature is determined using the results of molecular dynamics. Throughout, examples and results for metallic sodium are used. The treatment of the transition metal electronic d-states in terms of an effective pair-wise interaction is also discussed and the phonon dispersion curves of Al, Ni, and Cu are calculated.

  9. Adaptive Planning for Markov Decision Processes with Uncertain Transition Models via Incremental Feature Dependency Discovery

    E-Print Network [OSTI]

    Geramifard, Alborz

    Solving large scale sequential decision making problems without prior knowledge of the state transition model is a key problem in the planning literature. One approach to tackle this problem is to learn the state transition ...

  10. Early Warning Signals for Critical Transitions: A Generalized Modeling Approach

    E-Print Network [OSTI]

    rangelands [9], and desertification [10]. Warning signals for impending critical transitions are highly

  11. Dynamics of Molecular Motors in Reversible Burnt-Bridge Models

    E-Print Network [OSTI]

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

    2009-11-22

    Dynamic properties of molecular motors whose motion is powered by interactions with specific lattice bonds are studied theoretically with the help of discrete-state stochastic "burnt-bridge" models. Molecular motors are depicted as random walkers that can destroy or rebuild periodically distributed weak connections ("bridges") when crossing them, with probabilities $p_1$ and $p_2$ correspondingly. Dynamic properties, such as velocities and dispersions, are obtained in exact and explicit form for arbitrary values of parameters $p_1$ and $p_2$. For the unbiased random walker, reversible burning of the bridges results in a biased directed motion with a dynamic transition observed at very small concentrations of bridges. In the case of backward biased molecular motor its backward velocity is reduced and a reversal of the direction of motion is observed for some range of parameters. It is also found that the dispersion demonstrates a complex, non-monotonic behavior with large fluctuations for some set of parameters. Complex dynamics of the system is discussed by analyzing the behavior of the molecular motors near burned bridges.

  12. Modeling of Reactor Kinetics and Dynamics

    SciTech Connect (OSTI)

    Matthew Johnson; Scott Lucas; Pavel Tsvetkov

    2010-09-01

    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.

  13. DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL

    E-Print Network [OSTI]

    Mease, Kenneth D.

    DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL OVERVIEW Current/Completed Plug Power to garner SCAQMD funding for fuel cell testing GenCore system is sensitive to diluents · As built design stream to compensate for removal of EGR · Functionality of the modified GenCore Fuel Cell system

  14. Feature extraction for structural dynamics model validation

    SciTech Connect (OSTI)

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

    2010-11-08

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

  15. Fire Behavior Modeling - Experiment on Surface Fire Transition to the Elevated Live Fuel

    E-Print Network [OSTI]

    Omodan, Sunday

    2015-01-01

    fraction combustion model for fire simulation using CFD, TheCFD Computational Fluid Dynamics FDS Fire Dynamics Simulator FS Forest Service HoC Heat of Combustion

  16. Switched Dynamical Latent Force Models for Modelling Transcriptional Regulation

    E-Print Network [OSTI]

    López-Lopera, Andrés F

    2015-01-01

    In order to develop statistical approaches for transcription networks, statistical community has proposed several methods to infer activity levels of proteins, from time-series measurements of targets' expression levels. A few number of approaches have been proposed in order to outperform the representation of fast switching time instants, but computational overheads are significant due to complex inference algorithms. Using the theory related to latent force models (LFM), the development of this project provide a switched dynamical hybrid model based on Gaussian processes (GPs). To deal with discontinuities in dynamical systems (or latent driving force), an extension of the single input motif approach is introduced, that switches between different protein concentrations, and different dynamical systems. This creates a versatile representation for transcription networks that can capture discrete changes and non-linearities in the dynamics. The proposed method is evaluated on both simulated data and real data,...

  17. Noise-induced dynamic symmetry breaking and stochastic transitions in ABA molecules: II. Symmetricantisymmetric normal mode switching

    E-Print Network [OSTI]

    Cao, Jianshu

    Noise-induced dynamic symmetry breaking and stochastic transitions in ABA molecules: II. Symmetric molecules a b s t r a c t The second paper of the series discusses the effect of thermal noise on the stretching vibrational dynam- ics of symmetric triatomic ABA molecules. In particular, noise

  18. PHYSICAL REVIEW B 91, 205136 (2015) Exploring dynamical phase transitions and prethermalization with quantum noise of excitations

    E-Print Network [OSTI]

    Demler, Eugene

    2015-01-01

    changes. We discuss the characterization of such dynamical phase transitions based on the statistics is a subject of interest in many areas of physics involving cold- atomic gases [1], solid-state pump and probe and discuss a characterization of dynamical critical phenomena in bosonic systems based on the full statistics

  19. Absorbing Phase Transitions and Dynamic Freezing in Running Active Matter Systems

    E-Print Network [OSTI]

    C. Reichhardt; C. J. Olson Reichhardt

    2014-06-12

    We examine a two-dimensional system of sterically repulsive interacting disks where each particle runs in a random direction. This system is equivalent to a run-and-tumble dynamics system in the limit where the run time is infinite. At low densities, we find a strongly fluctuating state composed of transient clusters. Above a critical density that is well below the density at which non-active particles would crystallize, the system can organize into a drifting quiescent or frozen state where the fluctuations are lost and large crystallites form surrounded by a small density of individual particles. Although all the particles are still moving, their paths form closed orbits. The average transient time to organize into the quiescent state diverges as a power law upon approaching the critical density from above. We compare our results to the random organization observed for periodically sheared systems that can undergo an absorbing transition from a fluctuating state to a dynamical non-fluctuating state. In the random organization studies, the system organizes to a state in which the particles no longer interact; in contrast, we find that the randomly running active matter organizes to a strongly interacting dynamically jammed state. We show that the transition to the frozen state is robust against a certain range of stochastic fluctuations. We also examine the effects of adding a small number of pinned particles to the system and find that the transition to the frozen state shifts to significantly lower densities and arises via the nucleation of faceted crystals centered at the obstacles.

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

    E-Print Network [OSTI]

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

    2014-09-05

    , Phys. Rev. Lett. 98, 117204, (2007). 19P. J. Metaxas, R. L. Stamps, J.-P. Jamet, J. Ferr#2;e, V. Baltz, B. Rodmacq, and P. Politi, Phys. Rev. Lett. 104, 237206 (2010). 20N. Wiese, T. Dimopoulos, M. R€uhrig, J. Wecker, and G. Reiss, J. Appl. Phys. 98... 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...

  1. On connecting the dynamics of the chromosphere and transition region with Hinode SOT and EIS

    E-Print Network [OSTI]

    Viggo H. Hansteen; Bart De Pontieu; Mats Carlsson; Scott McIntosh; Tetsuya Watanabe; Harry Warren; Louise Harra; Hirohisa Hara; Theodore D. Tarbell; Dick Shine; Alan Title; Carolus J. Schrijver; Saku Tsuneta; Yukio Katsukawa; Kiyoshi Ichimoto; Yoshinori Suematsu; Toshifumi Shimizu

    2007-11-04

    We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric and TR imaging and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric magnetic fields and the ubiquitous chromospheric waves. Initial analysis shows that these connections are quite subtle and require a combination of techniques including magnetic field extrapolations, frequency-filtered time-series and comparisons with synthetic chromospheric and TR images from advanced 3D numerical simulations. As a first result, we find signatures of magnetic flux emergence as well as 3 and 5 mHz wave power above regions of enhanced photospheric magnetic field in both chromospheric, transition region and coronal emission.

  2. Correspondence between classical dynamics and energy level spacing distribution in the transition billiard systems

    E-Print Network [OSTI]

    Soo-Young Lee; Sunghwan Rim; Eui-Soon Yim; C. H. Lee

    1998-09-05

    The Robnik billiard is investigated in detail both classically and quantally in the transition range from integrable to almost chaotic system. We find out that a remarkable correspondence between characteristic features of classical dynamics, especially topological structure of integrable regions in the Poincar\\'{e} surface of section, and the statistics of energy level spacings appears with a system parameter $\\lambda$ being varied. It is shown that the variance of the level spacing distribution changes its behavior at every particular values of $\\lambda$ in such a way that classical dynamics changes its topological structure in the Poincar\\'{e} surface of section, while the skewness and the excess of the level spacings seem to be closely relevant to the interface structure between integrable region and chaotic sea rather than inner structure of intergrable regoin.

  3. Nanoscopic Dynamics of Phospholipid in Unilamellar Vesicles: Effect of Gel to Fluid Phase Transition

    SciTech Connect (OSTI)

    Sharma, Veerendra K [ORNL; Mamontov, Eugene [ORNL; Anunciado, Divina B [ORNL; O'Neill, Hugh Michael [ORNL; Urban, Volker S [ORNL

    2015-01-01

    Dynamics of phospholipids in unilamellar vesicles (ULV) is of interest in biology, medical, and food sciences since these molecules are widely used as biocompatible agents and a mimic of cell membrane systems. We have investigated the nanoscopic dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipid in ULV as a function of temperature using elastic and quasielastic neutron scattering (QENS). The dependence of the signal on the scattering momentum transfer, which is a critical advantage of neutron scattering techniques, allows the detailed analysis of the lipid motions that cannot be carried out by other means. In agreement with a differential scanning calorimetry measurement, a sharp rise in the elastic scattering intensity below ca. 296 K indicates a phase transition from the high-temperature fluid phase to the low-temperature solid gel phase. The microscopic lipid dynamics exhibits qualitative differences between the solid gel phase (in a measurement at 280 K) and the fluid phase (in a measurement at a physiological temperature of 310 K). The data analysis invariably shows the presence of two distinct motions: the whole lipid molecule motion within a monolayer, or lateral diffusion, and the relatively faster internal motion of the DMPC molecule. The lateral diffusion of the whole lipid molecule is found to be Fickian in character, whereas the internal lipid motions are of localized character, consistent with the structure of the vesicles. The lateral motion slows down by an order of magnitude in the solid gel phase, whereas for the internal motion not only the time scale, but also the character of the motion changes upon the phase transition. In the solid gel phase, the lipids are more ordered and undergo uniaxial rotational motion. However, in the fluid phase, the hydrogen atoms of the lipid tails undergo confined translation diffusion rather than uniaxial rotational diffusion. The localized translational diffusion of the hydrogen atoms of the lipid tails is a manifestation of the flexibility of the chains acquired in the fluid phase. Because of this flexibility, both the local diffusivity and the confinement volume for the hydrogen atoms increase linearly from near the lipid s polar head group to the end of its hydrophobic tail. Our results present a quantitative and detailed picture of the effect of the gel-fluid phase transition on the nanoscopic lipid dynamics in ULV. The data analysis approach developed here has a potential for probing the dynamic response of lipids to the presence of additional cell membrane components.

  4. Transactions in GIS Dynamic Modelling and Visualization on the Internet

    E-Print Network [OSTI]

    Worboys, Mike

    1 Transactions in GIS Dynamic Modelling and Visualization on the Internet Bo Huang* and Michael F for GIS to incorporate dynamic analytic models. At the same time, there is a need to distribute results of dynamic GIS using the Internet. Therefore, this paper sets out to explore the implementation of dynamic

  5. Representing aquifer architecture in macrodispersivity models with an analytical solution of the transition probability matrix

    E-Print Network [OSTI]

    Lu, Zhiming

    Representing aquifer architecture in macrodispersivity models with an analytical solution] The multi-dimensional transition probability model represents hydrofacies architecture in modeling aquifer heterogeneity. The structure of the aquifer architecture is mathematically characterized by a canonical

  6. Thermodynamics and the glass transition in model energy landscapes M. Scott Shell* and Pablo G. Debenedetti

    E-Print Network [OSTI]

    Thermodynamics and the glass transition in model energy landscapes M. Scott Shell* and Pablo G of a model energy landscape on the phase behavior of the liquid, including the glass transition. This model energy landscape corresponding to soft spheres with a mean-field attraction. We consider two

  7. Multiphase flow in the advanced fluid dynamics model

    SciTech Connect (OSTI)

    Bohl, W.R.; Wilhelm, D.; Berthier, J.; Parker, F.P.; Ichikawa, S.; Goutagny, L.; Ninokata, H.

    1988-01-01

    This paper describes the modeling used in the Advanced Fluid Dynamics Model (AFDM), a computer code to investigate new approaches to simulating severe accidents in fast reactors. The AFDM code has 12 topologies describing what material contacts are possible depending on the presence or absence of a given material in a computational cell, the dominant liquid, and the continuous phase. Single-phase, bubbly, churn-turbulent, cellular, and dispersed flow are permitted for the pool situations modeled. Interfacial areas between the continuous and discontinuous phases are convected to allow some tracking of phenomenological histories. Interfacial areas also are modified by models of nucleation, dynamic forces, turbulence, flashing, coalescence, and mass transfer. Heat transfer generally is treated using engineering correlations. Liquid/vapor phase transitions are handled with a nonequililbrium heat-transfer-limited model, whereas melting and freezing processes are based on equilibrium considerations. The Los Alamos SESAME equation of state (EOS) has been inplemented using densities and temperatures as the independent variables. A summary description of the AFDM numerical algorithm is provided. The AFDM code currently is being debugged and checked out. Two sample three-field calculations also are presented. The first is a three-phase bubble column mixing experiment performed at Argonne National Laboratory; the second is a liquid-liquid mixing experiment performed at Kernforschungszentrum, Karlsruhe, that resulted in rapid vapor production. We conclude that only qualitative comparisons currently are possible for complex multiphase situations. Many further model developments can be pursued, but there are limits because of the lack of a comprehensive theory, the lack of detailed multicomponent experimental data, and the difficulties in keeping the resulting model complexities tractable.

  8. A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,

    E-Print Network [OSTI]

    Nagurney, Anna

    of Operations & Information Management Isenberg School of Management University of Massachusetts AmherstA Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality of Massachusetts Amherst A Dynamic Network Oligopoly Model with Quality Competition #12;Acknowledgments

  9. Dynamic Properties of Molecular Motors in Burnt-Bridge Models

    E-Print Network [OSTI]

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

    2007-05-04

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

  10. Modeling Dynamics of Post Disaster Recovery 

    E-Print Network [OSTI]

    Nejat, Ali

    2012-10-19

    : Civil Engineering MODELING DYNAMICS OF POST DISASTER RECOVERY A Dissertation by ALI NEJAT Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR... OF PHILOSOPHY Approved by: Chair of Committee, Ivan Damnjanovic Committee Members, Stuart D. Anderson Kenneth F. Reinschmidt Sergiy Butenko Arnold Vedlitz Head of Department, John Niedzwecki August 2011 Major Subject: Civil Engineering...

  11. Regional Dynamics Model (REDYN) | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onRAPID/Geothermal/Exploration/Colorado <RAPID/Geothermal/WaterEnergyRedfield1989) Jump to:|OpenRegenesisDynamics Model

  12. DYNAMICAL MODELING OF GALAXY MERGERS USING IDENTIKIT

    SciTech Connect (OSTI)

    Privon, G. C.; Evans, A. S.; Barnes, J. E.; Hibbard, J. E.; Yun, M. S.; Mazzarella, J. M.; Armus, L.; Surace, J.

    2013-07-10

    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.

  13. Hydro-dynamical models for the chaotic dripping faucet

    E-Print Network [OSTI]

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

    2004-08-20

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

  14. Hydro-dynamical models for the chaotic dripping faucet

    E-Print Network [OSTI]

    Coullet, P; Riera, C S

    2004-01-01

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

  15. Glassy dynamics as a quantum corollary of the liquid to solid transition

    E-Print Network [OSTI]

    Zohar Nussinov

    2015-10-13

    We apply microcanonical ensemble and Eigenstate Thermalization Hypothesis considerations to posit that, whenever it may thermalize, a general disorder-free many-body Hamiltonian of a typical atomic system harbors solid-like eigenstates at low energies and fluid-type (and gaseous, plasma) eigenstates associated with energy densities exceeding those present in the melting (and, respectively, higher energy) transition(s). In particular, the lowest energy density at which the eigenstates of such a clean many body atomic system undergo a non-analytic change is that of the melting (or freezing) transition. We invoke this observation to analyze the evolution of a liquid upon supercooling (i.e., cooling rapidly enough to thwart solidification below the freezing temperature). Expanding the wavefunction of a supercooled liquid in the complete eigenbasis of the many-body Hamiltonian, only the higher energy liquid-type eigenstates contribute significantly to measurable hydrodynamic relaxations (e.g., those probed by viscosity) while static thermodynamic observables become weighted averages over both solid- and liquid-type eigenstates. Consequently, when extrapolated to low temperatures, hydrodynamic relaxation times of deeply supercooled liquids (i.e., glasses) may seem to diverge at nearly the same temperature at which the extrapolated entropy of the supercooled liquid becomes that of the solid. In this formal quantum framework, the increasingly sluggish (and spatially heterogeneous) dynamics in supercooled liquids as their temperature is lowered stems from the existence of the single non-analytic change of the eigenstates of the clean many-body Hamiltonian at the equilibrium melting transition (and associated translational and rotational symmetry breaking) present in low energy solid-type eigenstates. We provide a single parameter fit to the viscosity and suggest testable predictions.

  16. Sensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming

    E-Print Network [OSTI]

    Topaloglu, Huseyin

    of fleet management models is to make the vehicle repositioning and vehicle-to-load assignment decisions soSensitivity Analysis of a Dynamic Fleet Management Model Using Approximate Dynamic Programming present tractable algorithms to assess the sensitivity of a stochastic dynamic fleet management model

  17. Restoration of the Potosi Dynamic Model 2010

    SciTech Connect (OSTI)

    Adushita, Yasmin; Leetaru, Hannes

    2014-09-30

    In topical Report DOE/FE0002068-1 [2] technical performance evaluations on the Cambrian Potosi Formation were performed through reservoir modeling. The data included formation tops from mud logs, well logs from the VW1 and the CCS1 wells, structural and stratigraphic formation from three dimensional (3D) seismic data, and field data from several waste water injection wells for Potosi Formation. Intention was for two million tons per annum (MTPA) of CO2 to be injected for 20 years. In this Task the 2010 Potosi heterogeneous model (referred to as the "Potosi Dynamic Model 2010" in this report) was re-run using a new injection scenario; 3.2 MTPA for 30 years. The extent of the Potosi Dynamic Model 2010, however, appeared too small for the new injection target. It was not sufficiently large enough to accommodate the evolution of the plume. Also, it might have overestimated the injection capacity by enhancing too much the pressure relief due to the relatively close proximity between the injector and the infinite acting boundaries. The new model, Potosi Dynamic Model 2013a, was built by extending the Potosi Dynamic Model 2010 grid to 30 miles x 30 miles (48 km by 48 km), while preserving all property modeling workflows and layering. This model was retained as the base case. Potosi Dynamic Model 2013.a gives an average CO2 injection rate of 1.4 MTPA and cumulative injection of 43 Mt in 30 years, which corresponds to 45% of the injection target. This implies that according to this preliminary model, a minimum of three (3) wells could be required to achieve the injection target. The injectivity evaluation of the Potosi formation will be revisited in topical Report 15 during which more data will be integrated in the modeling exercise. A vertical flow performance evaluation could be considered for the succeeding task to determine the appropriate tubing size, the required injection tubing head pressure (THP) and to investigate whether the corresponding well injection rate falls within the tubing erosional velocity limit. After 30 years, the plume extends 15 miles (24 km) in E-W and 14 miles (22 km) in N-S directions. After injection is completed, the plume continues to migrate laterally, mainly driven by the remaining pressure gradient. After 100 years post-injection, the plume extends 17 miles (27 km) in E-W and 15 miles (24 km) in N-S directions. The increase of reservoir pressure at the end of injection is approximately 370 psia around the injector and gradually decreases away from the well. The reservoir pressure increase is less than 30 psia beyond 14 miles (22 km) away from injector. The initial reservoir pressure is restored after approximately 20 years post-injection. This result, however, is associated with uncertainties on the boundary conditions, and a sensitivity analysis could be considered for the succeeding tasks. It is important to remember that the respective plume extent and areal pressure increase corresponds to an injection of 43 Mt CO2. Should the targeted cumulative injection of 96 Mt be achieved; a much larger plume extent and areal pressure increase could be expected. Re-evaluating the permeability modeling, vugs and heterogeneity distributions, and relative permeability input could be considered for the succeeding Potosi formation evaluations. A simulation using several injectors could also be considered to determine the required number of wells to achieve the injection target while taking into account the pressure interference.

  18. 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 ...

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

    E-Print Network [OSTI]

    Laura Foini; Guilhem Semerjian; Francesco Zamponi

    2011-03-12

    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.

  20. Dislocation dynamics: from microscopic models to macroscopic crystal plasticity

    E-Print Network [OSTI]

    Hajj, A El; Monneau, R

    2009-01-01

    In this paper we study the connection between four models describing dislocation dynamics: a generalized 2D Frenkel-Kontorova model at the atomic level, the Peierls-Nabarro model, the discrete dislocation dynamics and a macroscopic model with dislocation densities. We show how each model can be deduced from the previous one at a smaller scale.

  1. Deconfinement Phase Transition with External Magnetic Field in Friedberg-Lee Model

    E-Print Network [OSTI]

    Shijun Mao

    2015-09-17

    The deconfinement phase transition with external magnetic field is investigated in the Friedberg-Lee model. In the frame of functional renormalization group, we extend the often used potential expansion method for continuous phase transitions to the first-order phase transition in the model. By solving the flow equations we find that, the magnetic field displays a catalysis effect and it becomes more difficult to break through the confinement in hot and dense medium.

  2. Transition in heterogeneous dynamics across the morphological hierarchy in two-dimensional aggregates

    E-Print Network [OSTI]

    Tamoghna Das; T. Lookman; M. M. Bandi

    2015-05-21

    Two-dimensional (2D) particulate aggregates formed due to competing interactions exhibit a range of non-equilibrium steady state morphologies from finite-size compact crystalline structures to non-compact string-like conformations. We report a transition in heterogeneous microscopic dynamics across this morphological hierarchy as a function of decreasing long-range repulsion relative to short-range attraction at a constant {\\it low} density and temperature. Following a very slow cooling protocol to form steady state aggregates, we show that geometric frustration inherent to competing interactions assures non-ergodicity of the system, which in turn results in long-time sub diffusive relaxation of the same. Analysing individual particle trajectories generated by molecular dynamics, we identify {\\it caging} dynamics of particles in compact clusters in contrast to the {\\it bonding} scenario for non-compact ones. Finally, by monitoring temperature dependence, we present a generic relation between diffusivity and structural randomness of the aggregates, irrespective of their thermodynamic equilibrium.

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    EOR continues to unlock oil resources. Oil & Gas Journal, [of conventional oil resource availability. Estimates ofthe tar sands and heavy oil resource in Figure 10. Note that

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    J. Regular conventional oil production to 2100 and resource10% of total US oil production in 2004, almost entirelysteam-induced heavy oil production in Cali- fornia [30].

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    crude-oil. This ?oor is required to support the productionoil production would spur development of SCPs as fast as has been seen historically for crudecrude-oil-equivalent fuels), the “emissions penalty” (in gigatonnes of carbon equivalent), and the total emissions from fuel production

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

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

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    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

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    31] NEB. Canada’s oil sands: opportunities and challenges toUtah. Technical report, Oil Sands Exploration Company and

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    31] NEB. Canada’s oil sands: opportunities and challenges toUtah. Technical report, Oil Sands Exploration Company andSupply Conventional oil Tar sands production GTL production

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    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,

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    in Figure 9 for tar sands and heavy oil. But, because of theregion for the tar sands and heavy oil resource in Figurewith small tar sands and heavy oil endowment use their

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    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

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    oil-like hydrocarbon fuels from non-conventional petroleumto hydrocarbon-based substitutes for conventional petroleum.liquid hydrocarbons, avail- ability of conventional oil, the

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    entirely from steam-induced heavy oil production in Cali-from Venezuela’s extra-heavy oil reached about 0.6 Mbbl/d inliquid fuels. Heavy and extra-heavy oil are very viscous and

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

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

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    based on projections of future prices and future demand.with demand projections, corresponding oil price series areoil price path associated with the IMAGE demand projection

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

    E-Print Network [OSTI]

    Brandt, Adam R.; Farrell, Alexander E.

    2008-01-01

    synfuels (GTL synfuels), coal-to-liquid synfuels (CTL syn-liquid fuels from non- petroleum feedstocks (coal andliquid fuels can also be produced, typically either from natural gas or coal.

  18. Lessons Learned from Alternative Transportation Fuels: Modeling Transition Dynamics

    Alternative Fuels and Advanced Vehicles Data Center [Office of Energy Efficiency and Renewable Energy (EERE)]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuels Data Center Home PageBlender PumpVehiclesThe Heat IsHeavy-DutyCELLsLessons

  19. Biomechanical modeling of register transitions and the role of vocal tract resonatorsa)

    E-Print Network [OSTI]

    Tokuda, Isao

    Biomechanical modeling of register transitions and the role of vocal tract resonatorsa) Isao T 31 July 2009 Biomechanical modeling and bifurcation theory are applied to study phonation onset at register transition? In order to address these problems, biomechanical mod- eling can complement

  20. Collapse transition of a hydrophobic self avoiding random walk in a coarse-grained model solvent

    E-Print Network [OSTI]

    Vinals, Jorge

    Collapse transition of a hydrophobic self avoiding random walk in a coarse-grained model solvent in a lattice model of a solvent. As expected, hydrophobic interactions lead to an attractive potential of mean force among chain segments. As a consequence, the random walk in solvent undergoes a collapse transition

  1. Economic transition, industrial location and corporate networks: Remaking the Sunan Model in Wuxi City, China

    E-Print Network [OSTI]

    Wei, Yehua Dennis

    Economic transition, industrial location and corporate networks: Remaking the Sunan Model in Wuxi-9155, USA Keywords: Sunan model Economic restructuring Industrial location Corporate network Wuxi China a b of institutional changes, economic transition and spatial restructuring. TVEs have been replaced by do- mestic

  2. Dynamical model for light composite fermions

    SciTech Connect (OSTI)

    Derman, E.

    1981-04-01

    A simple dynamical model for the internal structure of the three light lepton and quark generations (..nu../sub e/,e,u,d), (..nu../sub ..mu../,..mu..,c,s), and (..nu../sub tau/,tau,t,b) is proposed. Each generation is constructed of only one fundamental massive generation F=(L-italic/sup 0/,L/sup -/,U,D) with the same (SU/sub 3/)/sub c/ x SU/sub 2/ x U/sub 1/ quantum numbers as the light generations, bound to a core of one or more massive Higgs bosons H, where H is the single physical Higgs boson necessary for spontaneous symmetry breaking in the standard model. For example, e/sup -/=L/sup -/H), ..mu../sup -/=L/sup -/HH), tau/sup -/=L/sup -/HHH). It is shown that the known binding force due to H exchange is attractive and strong enough to produce light bound states. Dynamical calculations for the bound-state composite fermions using the Bethe-Salpeter equation, together with some phenomenological imput, suggest M/sub H/approx.16 TeV and M/sub F/approx.100 GeV. It is likely that such bound states can have properties compatible with the up to now apparently elementary appearance of known fermions, for example, their Dirac magnetic moments and absence of intergeneration radiative decays (such as ..mu -->..e..gamma..). Phenomenological consequences and tests of the model are discussed.

  3. Dynamic nuclear polarization with simultaneous excitation of electronic and nuclear transitions

    E-Print Network [OSTI]

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

    2008-05-28

    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.

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

    SciTech Connect (OSTI)

    Fernández-Pacheco, A., E-mail: af457@cam.ac.uk; Mansell, R.; Petit, D.; Lee, J. H.; Cowburn, R. P. [Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Ummelen, F. C.; Swagten, H. J. M. [Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2014-09-01

    We have designed a bilayer synthetic antiferromagnet where the order of layer reversal can be selected by varying the sweep rate of the applied magnetic field. The system is formed by two ultra-thin ferromagnetic layers with different proximities to the spin reorientation transition, coupled antiferromagnetically using Ruderman-Kittel-Kasuya-Yosida interactions. The different dynamic magnetic reversal behavior of both layers produces a crossover in their switching fields for field rates in the kOe/s range. This effect is due to the different effective anisotropy of both layers, added to an appropriate asymmetric antiferromagnetic coupling between them. Field-rate controlled selective switching of perpendicular magnetic anisotropy layers as shown here can be exploited in sensing and memory applications.

  5. Dynamic density field measurements of an explosively driven ????? phase transition in iron

    SciTech Connect (OSTI)

    Hull, L. M.; Gray, G. T.; Warthen, B. J.

    2014-07-28

    We provide a unique set of observations of the behavior of the ??? phase transition under a complex axially symmetric loading path created by sweeping a detonation wave along the end surface of a cylindrical sample. The primary data sets are the measured mass density distributions acquired at 5 independent times during the sweep of the detonation along the surface. Shocked regions and boundaries are measured, as well as regions and boundaries of elevated density (presumed to be the ??phase iron). The formation and dynamics of these regions were captured and are available for comparisons to material descriptions. We also applied 16 Photon Doppler Velocimetry probes to capture the free surface velocity along a discrete set of radially distributed points in order to compare and correlate the density measurements with previous shock wave studies. The velocimetry data are in nearly exact agreement with previous shock wave studies of the ??? phase transition, the density distributions, while generally in agreement with expectations evolved from the shock wave studies, show that the epsilon phase is generated in regions of high shear stress but at hydrostatic stresses below the typically quoted 13?GPa value. The density field measurements are particularly useful for observing the effects of the forward and reverse transformation kinetics, as well as the reverse transformation hysteresis.

  6. Nonlinear Hybrid Dynamical Systems: Modeling, Optimal Control, and Applications

    E-Print Network [OSTI]

    Stryk, Oskar von

    Nonlinear Hybrid Dynamical Systems: Modeling, Optimal Control, and Applications Martin Buss1¨unchen, Germany Abstract. Nonlinear hybrid dynamical systems are the main focus of this paper. A modeling Introduction The recent interest in nonlinear hybrid dynamical systems has forced the merger of two very

  7. Dynamical Systems Analysis of Various Dark Energy Models

    E-Print Network [OSTI]

    Nandan Roy

    2015-11-25

    In this thesis, we used dynamical systems analysis to find the qualitative behaviour of some dark energy models. Specifically, dynamical systems analysis of quintessence scalar field models, chameleon scalar field models and holographic models of dark energy are discussed in this thesis.

  8. Dynamical Systems Analysis of Various Dark Energy Models

    E-Print Network [OSTI]

    Roy, Nandan

    2015-01-01

    In this thesis, we used dynamical systems analysis to find the qualitative behaviour of some dark energy models. Specifically, dynamical systems analysis of quintessence scalar field models, chameleon scalar field models and holographic models of dark energy are discussed in this thesis.

  9. Neutron-antineutron transition as a test-bed for dynamical CPT violations

    E-Print Network [OSTI]

    Andrea Addazi

    2015-08-30

    We show a simple mechanism for a dynamical CPT violation in the neutron sector. In particular, we show a {\\it CPT-violating see-saw mechanism}, generating a Majorana mass and a CPT violating mass for the neutron. CPT-violating see-saw involves a sterile partner of the neutron, living in a hidden sector, in which CPT is spontaneously broken. In particular, neutrons (antineutrons) can communicate with the hidden sector through non-perturbative quantum gravity effects called {\\it exotic instantons}. Exotic instantons dynamically break R-parity, generating one effective vertex between the neutron and its sterile partner. In this way, we show how a small CPT violating mass term for the neutron is naturally generated. This model can be tested in the next generation of experiments in neutron-antineutron physics. This strongly motivates researches of CPT-violating effects in neutron-antineutron physics, as a test-bed for dynamical CPT-violations in SM.

  10. Linking the micro and macro: L-H transition dynamics and threshold...

    Office of Scientific and Technical Information (OSTI)

    flows. Turbulence driven shear flows are needed to trigger the transition by extracting energy from the turbulence. Thus, we identify the critical transition physics components...

  11. Linking Dynamical and Population Genetic Models of Persistent Viral Infection

    E-Print Network [OSTI]

    Kelly, John K.; Williamson, Scott; Orive, Maria E.; Smith, Marilyn S.; Holt, Robert D.

    2003-07-01

    This article develops a theoretical framework to link dynamical and population genetic models of persistent viral infection. This linkage is useful because, while the dynamical and population genetic theories have developed ...

  12. First-order electroweak phase transition in the standard model...

    Office of Scientific and Technical Information (OSTI)

    first-order phase transition to develop even with a Higgs boson mass well above the current direct limit of 114 GeV. The phisup 6 term can be generated for instance by...

  13. Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition

    E-Print Network [OSTI]

    Renate Landig; Ferdinand Brennecke; Rafael Mottl; Tobias Donner; Tilman Esslinger

    2015-03-18

    The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied due to the diluteness of the system. Here, we report on a direct, real-time and non-destructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system.

  14. Noise-Induced Dynamic Symmetry Breaking and Stochastic Transitions in ABA Molecules: I. Classification of Vibrational Modes

    E-Print Network [OSTI]

    Cao, Jianshu

    Noise-Induced Dynamic Symmetry Breaking and Stochastic Transitions in ABA Molecules: I. Under the influence of thermal noise, an ABA molecule switches between the four distinct modes equations in this paper and will be analyzed within the theoretical framework of noise-induced symmetry

  15. Orientational Ordering, Buckling, and Dynamic Transitions for Vortices Interacting with a Periodic Quasi-One Dimensional Substrate

    E-Print Network [OSTI]

    Q. Le Thien; D. McDermott; C. J. Olson Reichhardt; C. Reichhardt

    2015-08-21

    We examine the statics and dynamics of vortices in the presence of a periodic quasi-one dimensional substrate, focusing on the limit where the vortex lattice constant is smaller than the substrate lattice period. As a function of the substrate strength and filling factor, within the pinned state we observe a series of order-disorder transitions associated with buckling phenomena in which the number of vortex rows that fit between neighboring substrate maxima increases. These transitions coincide with steps in the depinning threshold, jumps in the density of topological defects, and changes in the structure factor. At the buckling transition the vortices are disordered, while between the buckling transitions the vortices form a variety of crystalline and partially ordered states. In the weak substrate limit, the buckling transitions are absent and the vortices form an ordered hexagonal lattice that undergoes changes in its orientation with respect to the substrate as a function of vortex density. At intermediate substrate strengths, certain ordered states appear that are correlated with peaks in the depinning force. Under an applied drive the system exhibits a rich variety of distinct dynamical phases, including plastic flow, a density-modulated moving crystal, and moving floating solid phases. We also find a dynamic smectic-to-smectic transition in which the smectic ordering changes from being aligned with the substrate to being aligned with the external drive. The different dynamical phases can be characterized using velocity histograms and the structure factor. We discuss how these results are related to recent experiments on vortex ordering on quasi-one-dimensional periodic modulated substrates. Our results should also be relevant for other types of systems such as ions, colloids, or Wigner crystals interacting with periodic quasi-one-dimensional substrates.

  16. Free Energy and Phase Transition of the Matrix Model on a Plane-Wave

    E-Print Network [OSTI]

    Shirin Hadizadeh; Bojan Ramadanovic; Gordon W. Semenoff; Donovan Young

    2004-10-05

    It has recently been observed that the weakly coupled plane wave matrix model has a density of states which grows exponentially at high energy. This implies that the model has a phase transition. The transition appears to be of first order. However, its exact nature is sensitive to interactions. In this paper, we analyze the effect of interactions by computing the relevant parts of the effective potential for the Polyakov loop operator in the finite temperature plane-wave matrix model to three loop order. We show that the phase transition is indeed of first order. We also compute the correction to the Hagedorn temperature to order two loops.

  17. Massive Neutron Stars with Hadron-Quark Transition Core : phenomenological approach by "3-window model"

    E-Print Network [OSTI]

    Tatsuyuki Takatsuka; Kota Masuda; Tetsuo Hatsuda

    2015-12-28

    By a new approach introducing a "3-window model" and constructing phenomenologically an equation of state for the hadron-quark (HQ) transition region, possible maximum mass of neutron stars (NSs) is discussed. It is found that neutron stars (NSs) with HQ transition core are able to have a mass exceeding two-solar mass, consistent with massive NSs recently observed.

  18. A Parallelizable and Approximate Dynamic Programming-Based Dynamic Fleet Management Model with

    E-Print Network [OSTI]

    Topaloglu, Huseyin

    -based dynamic fleet management model that can handle random load arrivals, random travel times and multiple-based model for the dynamic fleet management problem with random load arrivals, random travel times-based models for fleet management problems with random load arrivals, deterministic travel times and a single

  19. Solid Oxide Fuel Cell: Perspective of Dynamic Modeling and Control

    E-Print Network [OSTI]

    Huang, Biao

    Solid Oxide Fuel Cell: Perspective of Dynamic Modeling and Control Biao Huang Yutong Qi Monjur: This paper presents a review of state-of-the-art solid oxide fuel cells (SOFC), from perspective of dynamic. Keywords: Solid Oxide Fuel Cell, Control Relevant Model, Model Predictive Control 1. INTRODUCTION Today

  20. Dynamics of a multigroup epidemiological model with group ...

    E-Print Network [OSTI]

    Lamwah Chow

    2011-09-22

    spread across multiple countries and transmission between different subgroups in a ... Multigroup models have been used to study transmission dynamics of ...

  1. Asymptotic Approaches to Transition Modelling Stephen J. Cowley Xuesong Wu

    E-Print Network [OSTI]

    Cowley, Stephen J.

    characterising a fluid flow is its Reynolds number. Low-Reynolds-number flows are invariably laminar, the NS equations admit solutions which describe laminar flow, but such solutions may be unstable to small by which a laminar flow becomes turbulent is termed `transition'; the reverse process is usually referred

  2. Modeling the brittleductile transition in ferritic steels: dislocation simulations

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    fracture toughness values cannot be estimated; which should correspond to the ductile regime. The obtained the crack plane attains a critical value rF over a distance fracture is assumed to take place. The brittle­ductile transition curve is obtained by deter- mining the fracture toughness at various temperatures. Factors

  3. Deep Learning Helicopter Dynamics Models Ali Punjani and Pieter Abbeel

    E-Print Network [OSTI]

    Abbeel, Pieter

    Deep Learning Helicopter Dynamics Models Ali Punjani and Pieter Abbeel Abstract-- We consider the problem of system identification of helicopter dynamics. Helicopters are complex systems, cou- pling rigid inspiration from recent results in Deep Learning to represent the helicopter dynamics with a Rectified Linear

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

    E-Print Network [OSTI]

    Cervero, Robert; Murakami, Jin

    2008-01-01

    Development and Sustainable Urbanism While R+P projects arehigh-quality and sustainable urbanism is an important by-A model of sustainable transit finance and urbanism Robert

  5. Chirped-pulse millimeter-wave spectroscopy, dynamics, and manipulation of Rydberg-Rydberg Transitions

    E-Print Network [OSTI]

    Colombo, Anthony P. (Anthony Paul)

    2013-01-01

    The chirped-pulse millimeter-wave (CPmmW) technique is applied to transitions between Rydberg states, and calcium atoms are used as the initial test system. The unique feature of Rydberg{Rydberg transitions is that they ...

  6. Dynamical Reduction Models with General Gaussian Noises

    E-Print Network [OSTI]

    Angelo Bassi; GianCarlo Ghirardi

    2002-01-27

    We consider the effect of replacing in stochastic differential equations leading to the dynamical collapse of the statevector, white noise stochastic processes with non white ones. We prove that such a modification can be consistently performed without altering the most interesting features of the previous models. One of the reasons to discuss this matter derives from the desire of being allowed to deal with physical stochastic fields, such as the gravitational one, which cannot give rise to white noises. From our point of view the most relevant motivation for the approach we propose here derives from the fact that in relativistic models the occurrence of white noises is the main responsible for the appearance of untractable divergences. Therefore, one can hope that resorting to non white noises one can overcome such a difficulty. We investigate stochastic equations with non white noises, we discuss their reduction properties and their physical implications. Our analysis has a precise interest not only for the above mentioned subject but also for the general study of dissipative systems and decoherence.

  7. Nuclear Jacobi and Poincaré Transitions at High Spins and Temperatures: Account~of~Dynamic~Effects~and~Large-Amplitude Motion

    E-Print Network [OSTI]

    K. Mazurek; J. Dudek; A. Maj; D. Rouvel

    2013-08-14

    We present a theoretical analysis of the competition between so-called nuclear Jacobi and Poincar\\'e shape transitions in function of spin - at high temperatures. The latter condition implies the method of choice - a realistic version of the nuclear Liquid Drop Model (LDM), here: the Lublin-Strasbourg Drop (LSD) model. We address specifically the fact that the Jacobi and Poincar\\'e shape transitions are accompanied by the flattening of total nuclear energy landscape as function of the relevant deformation parameters what enforces large amplitude oscillation modes that need to be taken into account. For that purpose we introduce an approximate form of the collective Schr\\"odinger equation whose solutions are used to calculate the most probable deformations associated with both types of transitions and discuss the physical consequences in terms of the associated critical-spin values and transitions themselves.

  8. A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,

    E-Print Network [OSTI]

    Nagurney, Anna

    and Operations Management Isenberg School of Management University of Massachusetts Amherst, Massachusetts 01003A Dynamic Network Oligopoly Model with Transportation Costs, Product Differentiation, and Quality Network Oligopoly Model with Quality Competition #12;Acknowledgments This research was supported, in part

  9. Learning vehicular dynamics, with application to modeling helicopters

    E-Print Network [OSTI]

    Thrun, Sebastian

    Learning vehicular dynamics, with application to modeling helicopters Pieter Abbeel Computer Abstract We consider the problem of modeling a helicopter's dynamics based on state­action trajectories such as learned by CIFER (the industry standard in helicopter identification), and show that the linear

  10. Learning vehicular dynamics, with application to modeling helicopters

    E-Print Network [OSTI]

    Thrun, Sebastian

    Learning vehicular dynamics, with application to modeling helicopters Pieter Abbeel Computer Abstract We consider the problem of modeling a helicopter's dynamics based on state-action trajectories such as learned by CIFER (the industry standard in helicopter identification), and show that the linear

  11. Dynamic Modeling in Solid-Oxide Fuel Cells Controller Design

    SciTech Connect (OSTI)

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

    2007-06-28

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

  12. Developing a Dynamic Pharmacophore Model for HIV-1 Integrase

    SciTech Connect (OSTI)

    Carlson, Heather A.; Masukawa, Keven M.; Rubins, Kathleen; Bushman, Frederic; Jorgensen, William L.; Lins, Roberto; Briggs, James; Mccammon, Andy

    2000-05-11

    We present the first receptor-based pharmacophore model for HIV-1 integrase. The development of ''dynamic'' pharmacophore models is a new method that accounts for the inherent flexibility of the active site and aims to reduce the entropic penalties associated with binding a ligand. Furthermore, this new drug discovery method overcomes the limitation of an incomplete crystal structure of the target protein. A molecular dynamics (MD) simulation describes the flexibility of the uncomplexed protein. Many conformational models of the protein are saved from the MD simulations and used in a series of multi-unit search for interacting conformers (MUSIC) simulations. MUSIC is a multiple-copy minimization method, available in the BOSS program; it is used to determine binding regions for probe molecules containing functional groups that complement the active site. All protein conformations from the MD are overlaid, and conserved binding regions for the probe molecules are identified. Those conserved binding regions define the dynamic pharmacophore model. Here, the dynamic model is compared to known inhibitors of the integrase as well as a three-point, ligand-based pharmacophore model from the literature. Also, a ''static'' pharmacophore model was determined in the standard fashion, using a single crystal structure. Inhibitors thought to bind in the active site of HIV-1 integrase fit the dynamic model but not the static model. Finally, we have identified a set of compounds from the Available Chemicals Directory that fit the dynamic pharmacophore model, and experimental testing of the compounds has confirmed several new inhibitors.

  13. Lattice Spacing Dependence of the First Order Phase Transition for Dynamical Twisted Mass Fermions

    E-Print Network [OSTI]

    F. Farchioni; K. Jansen; I. Montvay; E. E. Scholz; L. Scorzato; A. Shindler; N. Ukita; C. Urbach; U. Wenger; I. Wetzorke

    2005-06-28

    Lattice QCD with Wilson fermions generically shows the phenomenon of a first order phase transition. We study the phase structure of lattice QCD using Wilson twisted mass fermions and the Wilson plaquette gauge action are used in a range of beta values where such a first order phase transition is observed. In particular, we investigate the dependence of the first order phase transition on the value of the lattice spacing. Using only data in one phase and neglecting possible problems arising from the phase transition we are able to perform a first scaling test for physical quantities using this action.

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

    E-Print Network [OSTI]

    Salman Habib; Emil Mottola; Peter Tinyakov

    1996-08-14

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

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

    E-Print Network [OSTI]

    Fringer, Oliver B.

    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

  16. Pool boilup analysis using the TRANSIT-HYDRO code with improved vapor/liquid drag models. [LMFBR

    SciTech Connect (OSTI)

    Wigeland, R.A.; Graff, D.L.

    1984-01-01

    The TRANSIT-HYDRO computer code is being developed to provide a tool for assessing the consequences of transition phase events in a hypothetical core disruptive accident in an LMFBR. The TRANSIT-HYDRO code incorporates detailed geometric modeling on a subassembly-by-subassembly basis and detailed modeling of reactor material behavior and thermal and hydrodynamic phenomena. The purpose of this summary is to demonstrate the validity of the improved vapor/liquid momentum exchange models in the TRANSIT-HYDRO code for a prototypic experiment and describe some implications for transition phase scenarios.

  17. A Phase Transition Model for By Christopher L. DeMarco

    E-Print Network [OSTI]

    by the electric power systems application. Efforts to date on these problems for power networks have focused circuits (including nonlinear inductive and capacitive elements) and classical models for electric powerA Phase Transition Model for By Christopher L. DeMarco A s the scale of engineered systems

  18. Generic solar photovoltaic system dynamic simulation model specification.

    SciTech Connect (OSTI)

    Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas

    2013-10-01

    This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.

  19. Phase Transitions in Hierarchical Models: The Role of Coupling

    E-Print Network [OSTI]

    ­entropy argument for this model, calculating the energy cost of inserting, in a system that finds itself in a pure argument based on the balance of energy and entropy of the model. The rigorous proof is then obtained. The first one is heuristic but in some sense clarifies the point we have in mind. We develop an energy

  20. Dynamic wind turbine models in power system simulation tool

    E-Print Network [OSTI]

    Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D. Hansen, Florin Iov Iov, Poul Sørensen, Nicolaos Cutululis, Clemens Jauch, Frede Blaabjerg Title: Dynamic wind turbine system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second

  1. Novel Dynamical Modeling for Series-Parallel Resonant Converter

    E-Print Network [OSTI]

    Noé, Reinhold

    and voltage waveforms in the resonant tank are assumed to be sinusoidal. Using this approach steady enables accurate calculation of steady-state characteristics under all (light to heavy) load conditions. For studying the dynamical behavior of the SPRC and for control design dynamical modeling techniques

  2. Fibre Based Modeling of Wood Dynamics and Fracture

    E-Print Network [OSTI]

    Bridson, Robert

    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

  3. Stochastic modeling of lift and drag dynamics under turbulent conditions

    E-Print Network [OSTI]

    Peinke, Joachim

    Matthias Wächter Joachim Peinke ForWind - Center for Wind Energy Research University of Oldenburg, Germany measurement. The model is being developed with the aim to integrate it into a general wind energy converter dynamics, drag dynamics. 1 Introduction Wind energy converters (WECs) are permanently exposed to turbulent

  4. Comparing Families of Dynamic Causal Models Will D. Penny1

    E-Print Network [OSTI]

    Daunizeau, Jean

    Comparing Families of Dynamic Causal Models Will D. Penny1 *, Klaas E. Stephan1,2 , Jean Daunizeau1: Penny WD, Stephan KE, Daunizeau J, Rosa MJ, Friston KJ, et al. (2010) Comparing Families of Dynamic, 2010; Published March 12, 2010 Copyright: Ã? 2010 Penny et al. This is an open-access article

  5. Aging of asymmetric dynamics on the random energy model

    E-Print Network [OSTI]

    Pierre Mathieu; Jean-Christophe Mourrat

    2013-03-20

    We show aging of Glauber-type dynamics on the random energy model, in the sense that we obtain the scaling limits of the clock process and of the age process. The latter encodes the Gibbs weight of the configuration occupied by the dynamics. Both limits are expressed in terms of stable subordinators.

  6. Dynamic Simulation Model of a Consumer Foods Production Process !

    E-Print Network [OSTI]

    Sun, Yu

    schedule based on product list The SIMUL8 Component 1. Over 200 lines of simula0on code 2. ReadsDynamic Simulation Model of a Consumer Foods Production Process ! Goals · Create a dynamic simula0 Created par0ally automated Excel files to go handin hand with simula0on o Contains all SKUs and meat

  7. Dynamic Modelling for Control of Fuel Cells Federico Zenith

    E-Print Network [OSTI]

    Skogestad, Sigurd

    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

  8. Glass-like dynamical behavior in hierarchical models submitted to continuous cooling and heating processes

    E-Print Network [OSTI]

    A. Prados; J. J. Brey

    2001-07-02

    The dynamical behavior of a kind of models with hierarchically constrained dynamics is investigated. The models exhibit many properties resembling real structural glasses. In particular, we focus on the study of time-dependent temperature processes. In cooling processes, a phenomenon analogous to the laboratory glass transition appears. The residual properties are analytically evaluated, and the concept of fictive temperature is discussed on a physical base. The evolution of the system in heating processes is governed by the existence of a normal solution of the evolution equations, which is approached by all the other solutions. This trend of the system is directly related to the glassy hysteresis effects shown by these systems. The existence of the normal solution is not restricted to the linear regime around equilibrium, but it is defined for any arbitrary, far from equilibrium, situation.

  9. REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump

    E-Print Network [OSTI]

    Fontecave-Jallon, Julie

    REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump Pascale Calabrese · Pierre Baconnier the relative motion of rib cage and abdomen during quiet breathing. Keywords Respiratory pump model Á. Hillman and Finucane (1987) have produced a simple model of the respiratory pump that ``appears

  10. A Diffusion Model in Population Genetics with Mutation and Dynamic

    E-Print Network [OSTI]

    O'Leary, Michael

    A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University May 24, 2008 Mike O'Leary (Towson University) A Diffusion Model in Genetics May Miller, Georgetown University Mike O'Leary (Towson University) A Diffusion Model in Genetics May 24, 2008

  11. 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

  12. A Compositional and Dynamic Model for Face Aging

    E-Print Network [OSTI]

    Zhu, Song Chun

    A Compositional and Dynamic Model for Face Aging Jinli Suo, Song-Chun Zhu, Shiguang Shan, Member model for face aging. The compositional model represents faces in each age group by a hierarchical And.) crucial for age perception and Or nodes represent large diversity of faces by alternative selections

  13. A Dynamic Island Model for Adaptive Operator Selection Caner Candan

    E-Print Network [OSTI]

    Goëffon, Adrien

    A Dynamic Island Model for Adaptive Operator Selection Caner Candan LERIA - University of Angers Angers, France caner.candan@univ-angers.fr Adrien Goëffon LERIA - University of Angers Angers, France

  14. Applications of axial and radial compressor dynamic system modeling

    E-Print Network [OSTI]

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

    2001-01-01

    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. ...

  15. Human Growth and Body Weight Dynamics: An Integrative Systems Model

    E-Print Network [OSTI]

    Rahmandad, Hazhir

    Quantifying human weight and height dynamics due to growth, aging, and energy balance can inform clinical practice and policy analysis. This paper presents the first mechanism-based model spanning full individual life and ...

  16. Modeling and control of undesirable dynamics in atomic force microscopes

    E-Print Network [OSTI]

    El Rifai, Osamah M

    2002-01-01

    The phenomenal resolution and versatility of the atomic force microscope (AFM), has made it a widely-used instrument in nanotechnology. In this thesis, a detailed model of AFM dynamics has been developed. It includes a new ...

  17. Model reduction for nonlinear dynamical systems with parametric uncertainties

    E-Print Network [OSTI]

    Zhou, Yuxiang Beckett

    2012-01-01

    Nonlinear dynamical systems are known to be sensitive to input parameters. In this thesis, we apply model order reduction to an important class of such systems -- one which exhibits limit cycle oscillations (LCOs) and ...

  18. Off-line calibration of Dynamic Traffic Assignment models

    E-Print Network [OSTI]

    Balakrishna, Ramachandran, 1978-

    2006-01-01

    Advances in Intelligent Transportation Systems (ITS) have resulted in the deployment of surveillance systems that automatically collect and store extensive network-wide traffic data. Dynamic Traffic Assignment (DTA) models ...

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

    E-Print Network [OSTI]

    2010-07-20

    J Dyn Diff Equat. DOI 10.1007/s10884-010-9178-x. Transmission Dynamics of an Influenza Model with Age of Infection and Antiviral Treatment. Zhipeng Qiu ...

  20. Fermi points and topological quantum phase transitions in a model of superconducting wires

    E-Print Network [OSTI]

    T. O. Puel; P. D. Sacramento; M. A. Continentino

    2015-06-01

    The importance of models with an exact solution for the study of materials with non-trivial topological properties has been extensively demonstrated. Among these, the Kitaev model of a one-dimensional $p$-wave superconductor plays a guiding role in the search for Majorana modes in condensed matter systems. Also, the $sp$ chain, with an anti-symmetric mixing among the $s$ and $p$ bands provides a paradigmatic example of a topological insulator with well understood properties. There is an intimate relation between these two models and in particular their topological quantum phase transitions share the same universality class. Here we consider a two-band $sp$ model of spinless fermions with an attractive (inter-band) interaction. Both the interaction and hybridization between the $s$ and $p$ fermions are anti-symmetric. The zero temperature phase diagram of the model presents a variety of phases including a Weyl superconductor, topological insulator and trivial phases. The quantum phase transitions between these phases can be either continuous or discontinuous. We show that the transition from the topological superconducting phase to the trivial one has critical exponents different from those of an equivalent transition in Kitaev's model.

  1. Transition from AdS universe to DS universe in the BPP model

    E-Print Network [OSTI]

    Wontae Kim; Myungseok Yoon

    2007-03-03

    It can be shown that in the BPP model the smooth phase transition from the asymptotically decelerated AdS universe to the asymptotically accelerated DS universe is possible by solving the modified semiclassical equations of motion. This transition comes from noncommutative Poisson algebra, which gives the constant curvature scalars asymptotically. The decelerated expansion of the early universe is due to the negative energy density with the negative pressure induced by quantum back reaction, and the accelerated late-time universe comes from the positive energy and the negative pressure which behave like dark energy source in recent cosmological models.

  2. Multi-resolution modeling of the dynamic loading of metal matrix...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Multi-resolution modeling of the dynamic loading of metal matrix composites. Citation Details In-Document Search Title: Multi-resolution modeling of the dynamic...

  3. Developing Generic Dynamic Models for the 2030 Eastern Interconnection Grid

    SciTech Connect (OSTI)

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

    2013-12-01

    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.

  4. Dynamic reactor modeling with applications to SPR and ZEDNA.

    SciTech Connect (OSTI)

    Suo-Anttila, Ahti Jorma

    2011-12-01

    A dynamic reactor model has been developed for pulse-type reactor applications. The model predicts reactor power, axial and radial fuel expansion, prompt and delayed neutron population, and prompt and delayed gamma population. All model predictions are made as a function of time. The model includes the reactivity effect of fuel expansion on a dynamic timescale as a feedback mechanism for reactor power. All inputs to the model are calculated from first principles, either directly by solving systems of equations, or indirectly from Monte Carlo N-Particle Transport Code (MCNP) derived results. The model does not include any empirical parameters that can be adjusted to match experimental data. Comparisons of model predictions to actual Sandia Pulse Reactor SPR-III pulses show very good agreement for a full range of pulse magnitudes. The model is also applied to Z-pinch externally driven neutron assembly (ZEDNA) type reactor designs to model both normal and off-normal ZEDNA operations.

  5. Modeling of Mode Transition Behavior in Argon Microhollow Cathode Discharges

    E-Print Network [OSTI]

    Raja, Laxminarayan L.

    in a metal/dielectric/ metal sandwich structure into which a through or blind hole is drilled. The thickness by the model for intermediate dis- charge currents ranging from about 0.1 to 0.3 mA. Plasma Process. Polym

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

    SciTech Connect (OSTI)

    Mubayi, V.; Leigh, R.W.; Bright, R.N.

    1996-03-01

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

  7. SUMMARY FOR POLICYMAKERS Modeling Optimal Transition Pathways to a Low

    E-Print Network [OSTI]

    California at Davis, University of

    of California Energy and Climate Policies 2 capture and sequestration or increased supplies of wind and solar and the social, environmental and economic aspects of major transformations. Energy models such as CA and sequestration (CCS). Elastic demand scenarios are also examined to reflect more realistic consumers' demand

  8. Coherent/incoherent metal transition in a holographic model

    E-Print Network [OSTI]

    Keun-Young Kim; Kyung Kiu Kim; Yunseok Seo; Sang-Jin Sin

    2014-12-13

    We study AC electric($\\sigma$), thermoelectric($\\alpha$), and thermal($\\bar{\\kappa}$) conductivities in a holographic model, which is based on 3+1 dimensional Einstein-Maxwell-scalar action. There is momentum relaxation due to massless scalar fields linear to spatial coordinate. The model has three field theory parameters: temperature($T$), chemical potential($\\mu$), and effective impurity($\\beta$). At low frequencies, if $\\beta metal). The parameters of this modified Drude peak are obtained analytically. In particular, if $\\beta \\ll \\mu$ the relaxation time of electric conductivity approaches to $2\\sqrt{3} \\mu/\\beta^2$ and the modified Drude peak becomes a standard Drude peak. If $\\beta > \\mu$ the shape of peak deviates from the Drude form(incoherent metal). At intermediate frequencies($T<\\omega<\\mu$), we have analysed numerical data of three conductivities($\\sigma, \\alpha, \\bar{\\kappa}$) for a wide variety of parameters, searching for scaling laws, which are expected from either experimental results on cuprates superconductors or some holographic models. In the model we study, we find no clear signs of scaling behaviour.

  9. Modelling the balanced transition to a sustainable economy

    E-Print Network [OSTI]

    Bastin, Georges

    of atmospheric carbon dioxide (CO2) which is the major contributor to greenhouse gas emissions. The model emissions, CO2 intensity, ecological Department of Mathematical Engineering, ICTEAM, Universit´e catholique. We consider a world economy with two subregions that are endowed with greenhouse gas emissions

  10. Dynamic competition model for construction contractors 

    E-Print Network [OSTI]

    Kim, Hyung Jin

    2004-01-01

    as an entity in a dynamic system, in which every entity is a profit optimizer responding to market conditions as well as its competitors' actions. In construction, the issue of competition has been focused on competitive bidding, which is a critical mechanism...

  11. Simulating the Transition from Drizzling Marine Stratocumulus to Boundary Layer Cumulus with a Mesoscale Model

    E-Print Network [OSTI]

    Mechem, David B.; Kogan, Yefim L.

    2003-10-01

    variability is analogous to the drizzle-induced cloud breakup produced in large eddy simulation studies. The dynamics of the pure stratocumulus cloud are dictated by the model's subgrid parameterization, while the more convective regime exhibits appreciable...

  12. Probing Reaction Dynamics of Transition-Metal Complexes in Solution via Time-Resolved X-ray Spectroscopy

    SciTech Connect (OSTI)

    Huse, Nils; Khalil, Munira; Kim, Tae Kyu; Smeigh, Amanda L.; Jamula, Lindsey; McCusker, James K.; Schoenlein, Robert W.

    2009-05-24

    We report measurements of the photo-induced Fe(II) spin crossover reaction dynamics in solution via time-resolved x-ray absorption spectroscopy. EXAFS measurements reveal that the iron?nitrogen bond lengthens by 0.21+-0.03 Angstrom in the high-spin transient excited state relative to the ground state. XANES measurements at the Fe L-edge show directly the influence of the structural change on the ligand-field splitting of the Fe(II) 3d orbitals associated with the spin transition.

  13. A stochastic evolutionary model for capturing human dynamics

    E-Print Network [OSTI]

    Fenner, Trevor; Loizou, George

    2015-01-01

    The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in various contexts. Here we propose a generative model to capture the dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. We derive a general solution for the model in the form of a product, and then a continuous approximation to the solution via the renewal equation describing age-structured population dynamics. This enables us to model a wide rage of survival distributions, according to the choice of the mortality distribution. We provide empirical evidence for the validity of the model from a longitudinal data set of popular search engine queries over 114 months, showing that the survival function of these queries is closely matched by the solution for our model with power-law mortality.

  14. Structure formation: Models, Dynamics and Status

    E-Print Network [OSTI]

    T. Padmanabhan

    1995-08-25

    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.

  15. Modeling emotion dynamics in intelligent agents 

    E-Print Network [OSTI]

    Seif El-Nasr, Magy

    1998-01-01

    Emotions were shown to have a leading role in the human decision-making process, and thus they play an important role in human intelligence. Intelligent agents' research produced many models of emotional agents. However, most of these models focused...

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

    E-Print Network [OSTI]

    Weeks, Eric R.

    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

  17. The Slowdowns of Water Dynamics when Approaching a Glass Transition or a Solid Interface: A Common Rationale

    E-Print Network [OSTI]

    Felix Klameth; Michael Vogel

    2015-06-18

    Performing molecular dynamics simulations, we investigate the enormous slowdowns of water dynamics when approaching a glass transition or a solid interface. We show that both effects can be described on common grounds within a theoretical framework, which was recently proposed by Schweizer et al. and considers coupled local hopping and elastic distortion. For confined water, we correctly describe the variation of the alpha-relaxation time tau_alpha as a function of both temperature and position with respect to the interface. Exploiting our knowledge of a cooperative length scale xi(T) from the confinement studies, we quantitatively rationalize the glassy slowdown, tau_alpha(T), and the Stokes-Einstein breakdown of bulk water. For both confined and bulk liquid, variations of the alpha-relaxation time are intimately related to changes of the cage-rattling amplitude.

  18. Turbulent transition in a truncated 1D model for shear flow

    E-Print Network [OSTI]

    Dawes, Jon

    to a `turbulent' state (i) takes place more abruptly, with a boundary between laminar and `turbulent' flow at fixed Reynolds number are found to be consistent with exponential distributions. Keywords: fluid flowTurbulent transition in a truncated 1D model for shear flow By J. H. P. Dawes and W. J. Giles

  19. Phase transitions in the majority-vote model with two types of noises

    E-Print Network [OSTI]

    Vieira, Allan R

    2015-01-01

    In this work we study the majority-vote model with the presence of two distinc noises. The first one is the usual noise $q$, that represents the probability that a given agent follows the minority opinion of his/her social contacts. On the other hand, we consider the independent behavior, such that an agent can choose his/her own opinion $+1$ or $-1$ with equal probability, independent of the group's norm. We study the impact of the presence of such two kinds of stochastic driving in the phase transitions of the model, considering the mean field and the square lattice cases. Our results suggest that the model undergoes a nonequilibrium order-disorder phase transition even in the absence of the noise $q$, due to the independent behavior, but this transition may be suppressed. In addition, for both topologies analyzed, we verified that the transition is in the same universality class of the equilibrium Ising model, i.e., the critical exponents are not affected by the presence of the second noise, associated wit...

  20. Modeling of rate-dependent phase transition in bacterial flagellar filament Xiaoling Wang a

    E-Print Network [OSTI]

    Sun, Qing-Ping

    Modeling of rate-dependent phase transition in bacterial flagellar filament Xiaoling Wang for bacteria. The long helical filament is the propeller made up of only one kind of protein called flagellin [2,3]. Macroscopically the filament can be viewed as a hollow tube with an outer diameter of 20 nm

  1. The Two-Pathway Model for the Catch-Slip Transition in Biological Adhesion

    E-Print Network [OSTI]

    The Two-Pathway Model for the Catch-Slip Transition in Biological Adhesion Yuriy V. Pereverzev. (1) in a mathematical description of membrane-to- surface adhesion and detachment. In this work adhesion protein FimH was shown to undergo a force-induced conformational change that led to stronger

  2. DETAILED CHEMICAL KINETIC MODELING OF ISO-OCTANE SI-HCCI TRANSITION

    SciTech Connect (OSTI)

    Havstad, M A; Aceves, S M; McNenly, M J; Piggott, W T; Edwards, K D; Wagner, R M; Daw, C S; Finney, C A

    2009-10-12

    The authors describe a CHEMKIN-based multi-zone model that simulates the expected combustion variations in a single-cylinder engine fueled with iso-octane as the engine transitions from spark-ignited (ST) combustion to homogeneous charge compression ignition (HCCI) combustion. The model includes a 63-species reaction mechanism and mass and energy balances for the cylinder and the exhaust flow. For this study they assumed that the SI-to-HCCI transition is implemented by means of increasing the internal exhaust gas recirculation (EGR) at constant engine speed. This transition scneario is consistent with that implemented in previously reported experimental measurements on an experimental engine equipped with variable valve actuation. They find that the model captures many of the important experimental trends, including stable SI combustion at low EGR ({approx} 0.10), a transition to highly unstable combustion at intermediate EGR, and finally stable HCCI combustion at very high EGR ({approx} 0.75). Remaining differences between the predicted and experimental instability patterns indicate that there is further room for model improvement.

  3. Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene Translation

    E-Print Network [OSTI]

    Margaliot, Michael

    1 Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several artificial biological systems that entrain to a common

  4. Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene Translation

    E-Print Network [OSTI]

    Sontag, Eduardo

    Entrainment to Periodic Initiation and Transition Rates in a Computational Model for Gene to the solar day. In the terminology of systems theory, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several

  5. Monte Carlo study of very weak first-order transitions in the three-dimensional Ashkin-Teller model

    E-Print Network [OSTI]

    Peter Arnold; Yan Zhang

    1997-07-10

    We propose numerical simulations of the Ashkin-Teller model as a foil for theoretical techniques for studying very weakly first-order phase transitions in three dimensions. The Ashkin-Teller model is a simple two-spin model whose parameters can be adjusted so that it has an arbitrarily weakly first-order phase transition. In this limit, there are quantities characterizing the first-order transition which are universal: we measure the relative discontinuity of the specific heat, the correlation length, and the susceptibility across the transition by Monte Carlo simulation.

  6. A direct ab inifio dynamics approach for calculating thermal rate constants using variational transition state theory

    E-Print Network [OSTI]

    Truong, Thanh N.

    of a focusing technique to minimize the number of electronic structure calculations, while still preservingA direct ab inifio dynamics approach for calculating thermal rate constants using variational dynamics, " for calculations of thermal rate constants and related properties from first principles

  7. A covariant model for the gamma N -> N(1535) transition at high momentum transfer

    SciTech Connect (OSTI)

    G. Ramalho, M.T. Pena

    2011-08-01

    A relativistic constituent quark model is applied to the gamma N -> N(1535) transition. The N(1535) wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the S11 resonance. The model allows us to calculate the valence quark contributions to the gamma N -> N(1535) transition form factors. Because of the nucleon and N(1535) structure the model is valid only for Q^2> 2.3 GeV^2. The results are compared with the experimental data for the electromagnetic form factors F1* and F2* and the helicity amplitudes A_1/2 and S_1/2, at high Q^2.

  8. Phase transitions in multi-cut matrix models and matched solutions of Whitham hierarchies

    E-Print Network [OSTI]

    Gabriel Alvarez; Luis Martinez Alonso; Elena Medina

    2010-01-25

    We present a method to study phase transitions in the large N limit of matrix models using matched solutions of Whitham hierarchies. The endpoints of the eigenvalue spectrum as functions of the temperature are characterized both as solutions of hodograph equations and as solutions of a system of ordinary differential equations. In particular we show that the free energy of the matrix model is the quasiclassical tau-function of the associated hierarchy, and that critical processes in which the number of cuts changes in one unit are third-order phase transitions described by C1 matched solutions of Whitham hierarchies. The method is illustrated with the Bleher-Eynard model for the merging of two cuts. We show that this model involves also a birth of a cut.

  9. Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire

    E-Print Network [OSTI]

    Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire Engineering Assessment Yong S (CFD) Modelling is now widely used by fire safety engineers throughout the world as a tool of the smoke control design as part of the performance based fire safety design in the current industry

  10. Dislocation dynamics: from microscopic models to macroscopic crystal plasticity

    E-Print Network [OSTI]

    El Hajj, Ahmad

    Dislocation dynamics: from microscopic models to macroscopic crystal plasticity A. El Hajj , H study ranges from atomic models to macroscopic crystal plasticity. At each scale, dislocations can crystal Z3 where each position with integer coordinates is occupied by one atom. We want to describe

  11. Fluid Dynamic Models of Flagellar and Ciliary Beating

    E-Print Network [OSTI]

    Fauci, Lisa

    University, New Orleans, Louisiana, USA ABSTRACT: We have developed a fluid­mechanical model of a eucaryotic mechanics of microtubules, and forces due to nexin links with a surrounding incompressible fluid. This model mechanisms, the passive elastic structure of the axoneme, and the external fluid dynamics. These flagellar

  12. SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL

    E-Print Network [OSTI]

    ii SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL: A LOOK the likely effects of alternative policies, potential adoption rates of clean technologies, and costs to society in the long run. My goal was to use a "hybrid" energy economy model (CIMS), which combines

  13. A STOCHASTIC CELLULAR AUTOMATON MODEL OF EBOLA VIRUS DYNAMICS

    E-Print Network [OSTI]

    Hawkins, Jane M.

    A STOCHASTIC CELLULAR AUTOMATON MODEL OF EBOLA VIRUS DYNAMICS E. BURKHEAD AND J. HAWKINS Abstract. We construct a stochastic cellular automaton (SCA) model for the spread of the Ebola virus (EBOV). We of virus and the typical immune response to it, and the differences which reflect the drastically different

  14. 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

  15. A Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae

    E-Print Network [OSTI]

    Boyer, Edmond

    in microalgae, thereby spanning multiple time scales. The properties of the model are investigated under quasi2 mitigation due to their inherent consumption of CO2 during photosynthesis, they can be coupledA Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae Philipp Hartmann1

  16. Numerically Estimating Internal Models of Dynamic Virtual Objects

    E-Print Network [OSTI]

    Sekuler, Robert

    human subjects to manipulate a computer-animated virtual object. This virtual object (vO) was a high, human cognition, human information processing, ideal performer, internal model, virtual object, virtual, specifically how humans acquire an internal model of a dynamic virtual object. Our methodology minimizes

  17. Modeling and simulation of consumer response to dynamic pricing.

    SciTech Connect (OSTI)

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

    2012-08-01

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

  18. Dynamical many-body localization in an integrable model

    E-Print Network [OSTI]

    Aydin Cem Keser; Sriram Ganeshan; Gil Refael; Victor Galitski

    2015-06-17

    We investigate dynamical many-body localization and delocalization in an integrable system of periodically-kicked, interacting linear rotors. The Hamiltonian we investigate is linear in momentum, and its Floquet evolution operator is analytically tractable for arbitrary interaction strengths. One of the hallmarks of this model is that depending on certain parameters, it manifest both localization and delocalization in momentum space. We explicitly show that, for this model, the energy being bounded at long times is not a sufficient condition for dynamical localization. Besides integrals of motion associated to the integrability, this model manifests additional integrals of motion, which are the exclusive consequence of dynamical many-body localization. We also propose an experimental scheme, involving voltage-biased Josephson junctions, to realize such many-body kicked models.

  19. Magnetic field induced quantum phase transitions in the two-impurity Anderson model

    SciTech Connect (OSTI)

    Zhu, Lujun; Zhu, Jian - Xin

    2010-11-17

    In the two-impurity Anderson model, the inter-impurity spin exchange interaction favors a spin singlet state between two impurities leading to the localization of quasiparticles. We show that a local uniform magnetic field can delocalize the quasiparticies to restore the Kondo resonance. This transition is found to be continuous, accompanied by not only the divergence of the staggered (anti ferromagnetic) susceptibility, but also the divergence of the uniform spin susceptibility. This implies that the magnetic field induced quantum phase transitions in Kondo systems are in favor of the local critical type.

  20. DYNAMICAL MODEL OF AN EXPANDING SHELL

    SciTech Connect (OSTI)

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

    2012-06-10

    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.

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

    E-Print Network [OSTI]

    Hohls, Frank

    , they occur only at zero temperature [1]. However, as long as the quantum fluctuations governing transitions occur at a critical value of a parameter which can be, e.g., the disorder in the metal system is the distance from a critical energy Ec which can be identified as the center of a disorder

  2. Dynamics of many-body localisation in a translation invariant quantum glass model

    E-Print Network [OSTI]

    Merlijn van Horssen; Emanuele Levi; Juan P. Garrahan

    2015-05-26

    We study the real-time dynamics of a translationally invariant quantum spin chain, based on the East kinetically constrained glass model, in search for evidence of many-body localisation in the absence of disorder. Numerical simulations indicate a change, controlled by a coupling parameter, from a regime of fast relaxation---corresponding to thermalisation---to a regime of very slow relaxation. This slowly relaxing regime is characterised by dynamical features usually associated with non-ergodicity and many-body localisation (MBL): memory of initial conditions, logarithmic growth of entanglement entropy, and non-exponential decay of time-correlators. We show that slow relaxation is a consequence of sensitivity to spatial fluctuations in the initial state. While numerics indicate that certain relaxation timescales grow markedly with size, our finite size results are consistent both with an MBL transition, expected to only occur in disordered systems, or with a pronounced quasi-MBL crossover.

  3. Pluripotency, differentiation, and reprogramming: A gene expression dynamics model with epigenetic feedback regulation

    E-Print Network [OSTI]

    Miyamoto, Tadashi; Kaneko, Kunihiko

    2015-01-01

    Characterization of pluripotent states, in which cells can both self-renew and differentiate, and the irreversible loss of pluripotency are important research areas in developmental biology. In particular, an understanding of these processes is essential to the reprogramming of cells for biomedical applications, i.e., the experimental recovery of pluripotency in differentiated cells. Based on recent advances in dynamical-systems theory for gene expression, we propose a gene-regulatory-network model consisting of several pluripotent and differentiation genes. Our results show that cellular-state transition to differentiated cell types occurs as the number of cells increases, beginning with the pluripotent state and oscillatory expression of pluripotent genes. Cell-cell signaling mediates the differentiation process with robustness to noise, while epigenetic modifications affecting gene expression dynamics fix the cellular state. These modifications ensure the cellular state to be protected against external per...

  4. Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead-Free Electronics

    E-Print Network [OSTI]

    Sandborn, Peter

    Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead the cost ramifications of the transition from tin- lead to lead-free electronic parts. All tin-lead, all lead-free and mixed assembly approaches are considered. The model makes basic assumptions of a fixed

  5. Slow dynamics in a model of the cellulose network

    E-Print Network [OSTI]

    O. V. Manyuhina; A. Fasolino; M. I. Katsnelson

    2007-06-07

    We present numerical simulations of a model of cellulose consisting of long stiff rods, representing cellulose microfibrils, connected by stretchable crosslinks, representing xyloglucan molecules, hydrogen bonded to the microfibrils. Within a broad range of temperature the competing interactions in the resulting network give rise to a slow glassy dynamics. In particular, the structural relaxation described by orientational correlation functions shows a logarithmic time dependence. The glassy dynamics is found to be due to the frustration introduced by the network of xyloglucan molecules. Weakening of interactions between rod and xyloglucan molecules results in a more marked reorientation of cellulose microfibrils, suggesting a possible mechanism to modify the dynamics of the plant cell wall.

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

    E-Print Network [OSTI]

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

    2015-01-01

    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...

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

    E-Print Network [OSTI]

    Ghrist, Melissa Renee

    2009-05-15

    This thesis compares air/water two-phase flow regime transition models in zero gravity with data and makes recommendations for zero gravity models to incorporate into the RELAP5-3D thermal hydraulic computer code. Data ...

  8. STOCHASTIC DYNAMICS OF A COUPLED ATMOSPHEREOCEAN MODEL

    E-Print Network [OSTI]

    's longwave radiation coefficient and the shortwave solar radiation profile. Third, we have demon- strated this coupled atmosphere-ocean model consists of stochastic Date: February 5, 2002. 1991 Mathematics Subject

  9. Generative modeling of dynamic visual scenes

    E-Print Network [OSTI]

    Lin, Dahua, Ph. D. Massachusetts Institute of Technology

    2012-01-01

    Modeling visual scenes is one of the fundamental tasks of computer vision. Whereas tremendous efforts have been devoted to video analysis in past decades, most prior work focuses on specific tasks, leading to dedicated ...

  10. Modeling Infection with Multi-agent Dynamics

    E-Print Network [OSTI]

    Dong, Wen

    2012-01-01

    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 ...

  11. A one parameter fit for glassy dynamics as a quantum corollary of the liquid to solid transition

    E-Print Network [OSTI]

    Zohar Nussinov

    2015-12-21

    We apply microcanonical ensemble considerations to posit that, whenever it may thermalize, a general disorder-free many-body Hamiltonian of a typical atomic system harbors solid-like eigenstates at low energies and fluid-type (and gaseous, plasma) eigenstates associated with energy densities exceeding those present in the melting (and, respectively, higher energy) transition(s). In particular, the lowest energy density at which the eigenstates of such a clean many body atomic system undergo a non-analytic change is that of the melting (or freezing) transition. We invoke this observation to analyze the evolution of a liquid upon supercooling (i.e., cooling rapidly enough to thwart solidification below the freezing temperature). Expanding the wavefunction of a supercooled liquid in the complete eigenbasis of the many-body Hamiltonian, only the higher energy liquid-type eigenstates contribute significantly to measurable hydrodynamic relaxations (e.g., those probed by viscosity) while static thermodynamic observables become weighted averages over both solid- and liquid-type eigenstates. Consequently, when extrapolated to low temperatures, hydrodynamic relaxation times of deeply supercooled liquids (i.e., glasses) may seem to diverge at nearly the same temperature at which the extrapolated entropy of the supercooled liquid becomes that of the solid. In this formal quantum framework, the increasingly sluggish (and spatially heterogeneous) dynamics in supercooled liquids as their temperature is lowered stems from the existence of the single non-analytic change of the eigenstates of the clean many-body Hamiltonian at the equilibrium melting transition (and associated translational and rotational symmetry breaking) present in low energy solid-type eigenstates. We derive a single (possibly computable) dimensionless parameter fit to the viscosity and suggest testable predictions.

  12. QCD Phase Transition in Brans-Dicke DGP model of Brane Gravity

    E-Print Network [OSTI]

    T. Golanbari; A. Mohammadi; Kh. Saaidi

    2014-08-24

    A DGP brane-world model with a perfect fluid brane matter including a Brans-Dicke (BD) scalar field on brane has been utilized to investigate the problem of quark-hadron phase (QHP) transition in early times of the Universe evoltion. The presence of BD scalar field came up with some modification terms in the Friedmann equation, however we have a usual form of conservation equation for brane matter since scalar field only has a non-mnimally interaction with geometry. Behavior of phase transition strongly depends on the basic evolution equations. Then, even a small change in these relation might come to interesting results about the time of transition. Two different formalisms as smooth crossover formalism in which lattice QCD data is used for obtaining the matter equation of state and first-order phase transition formalism, have been used to investigate of the evolution of physical quatities relevant to quantitative of early times such as energy density $\\rho$, scale factor $a$, and temperature $T$. The obtained results show that the general behavior of temperature is similar in both of two formalisms and the QHP transition occurred at about micro-second after the Big Bang.

  13. A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

    SciTech Connect (OSTI)

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-03-20

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore, by integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.

  14. A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

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

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-03-20

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore,more »by integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.« less

  15. Shell model method for Gamow-Teller transitions in heavy, deformed nuclei

    SciTech Connect (OSTI)

    Gao Zaochun [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China); Sun Yang [Joint Institute for Nuclear Astrophysics and Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Chen, Y.-S. [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Institute of Theoretical Physics, Academia Sinica, Beijing 100080 (China)

    2006-11-15

    A method for calculation of Gamow-Teller transition rates is developed by using the concept of the Projected Shell Model (PSM). The shell model basis is constructed by superimposing angular-momentum-projected multiquasiparticle configurations, and nuclear wave functions are obtained by diagonalizing the two-body interactions in these projected states. Calculation of transition matrix elements in the PSM framework is discussed in detail, and the effects caused by the Gamow-Teller residual forces and by configuration-mixing are studied. With this method, it may become possible to perform a state-by-state calculation for {beta}-decay and electron-capture rates in heavy, deformed nuclei at finite temperatures. Our first example indicates that, while experimentally known Gamow-Teller transition rates from the ground state of the parent nucleus are reproduced, stronger transitions from some low-lying excited states are predicted to occur, which may considerably enhance the total decay rates once these nuclei are exposed to hot stellar environments.

  16. CSAW: a dynamical model of protein folding

    E-Print Network [OSTI]

    Kerson Huang

    2006-01-12

    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.

  17. Analytical properties of a three-compartmental dynamical demographic model

    E-Print Network [OSTI]

    E. B. Postnikov

    2015-07-29

    The three-compartmental demographic model by Korotaeyv-Malkov-Khaltourina, connecting population size, economic surplus, and educational level, is considered from the point of view of dynamical systems theory. It is shown that there exist two integrals of motion, which enable the system to be reduced to one non-linear ordinary differential equation. The study of its structure provides analytical criteria for the dominance ranges of the dynamics of Malthus and Kremer. Additionally, the particular ranges of parameters enable the derived general ordinary differential equations to be reduced to the models of Gompertz and Thoularis-Wallace.

  18. Model Based Safety Assessment Dynamic System

    E-Print Network [OSTI]

    Grigoras, .Romulus

    Assessment Techniques ·Failure mode and effect analysis (FMEA) ­ Model: from a local failure to its system chain .... 2 Functional FMEA template FT unannunciated loss of wheel braking #12;Drawbacks of the Classical Safety Assessment Techniques · Fault Tree, FMEA ­ Give failure propagation paths without referring

  19. Green Algae as Model Organisms for Biological Fluid Dynamics

    E-Print Network [OSTI]

    Goldstein, Raymond E

    2014-01-01

    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...

  20. Green Algae as Model Organisms for Biological Fluid Dynamics

    E-Print Network [OSTI]

    Raymond E. Goldstein

    2014-09-08

    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.

  1. Modeling Dynamic Landscapes in Open Source GIS

    E-Print Network [OSTI]

    Mitasova, Helena

    2013-11-20

    is free online • message board discussion, help • Google sites: post HW, get feedback • register to get credit Solar radiation modeling: monthly totals Applications in urban areas: solar panels, building design, thermal conditions,… Helena Mitasova, NCSU... topics: • Solar energy potential • Coastal hazards • Watershed analysis • Trail and greenway design • Lidar data processing Most students use ArcGIS but number of students who use GRASS for at least part of their project is increasing every semester...

  2. An efficient model of drillstring dynamics

    E-Print Network [OSTI]

    Butlin, T.; Langley, R. S.

    2015-07-23

    Vibration problems represent a significant cost to the oilwell drilling industry due to a wide range of problematic phenomena that can occur [1]. Torsional vibration can cause fatigue, damage to the drillbit if the direction of rotation periodically reverses... ,14]). There are many other effects that could be included in a drillstring model, such as fluid-structure interaction, the effect of free particles at frictional and cutting interfaces, well-path tortu- osity, mud-pump excitation, and buckling. It is clear...

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

    SciTech Connect (OSTI)

    Greene, David L

    2007-02-01

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

  4. Modelling flow pattern transitions for steady upward gas-liquid flow in vertical tubes. [Bubble, slug, churn and dispersed-annular; also existence regions and transitions

    SciTech Connect (OSTI)

    Taitel, Y. (Tel-Aviv Univ., Israel); Bornea, D.; Dukler, A.E.

    1980-05-01

    Models for predicting flow patterns in steady upward gas-liquid flow in vertical tubes (such as production-well tubing) delineate the transition boundaries between each of the four basic flow patterns for gas-liquid flow in vertical tubes: bubble, slug, churn, and dispersed-annular. Model results suggest that churn flow is the development region for the slug pattern and that bubble flow can exist in small pipes only at high liquid rates, where turbulent dispersion forces are high. Each transition depends on the flow-rate pair, fluid properties, and pipe size, but the nature of the dependence is different for each transition because of differing control mechanisms. The theoretical predictions are in reasonably good agreement with a variety of published flow maps based on experimental data.

  5. Minimal cooling speed for glass transition in a simple solvable energy landscape model

    E-Print Network [OSTI]

    J. Quetzalcóatl Toledo-Marín; Isaac Pérez Castillo; Gerardo G. Naumis

    2015-10-28

    The minimal cooling speed required to form a glass is obtained for a simple solvable energy landscape model. The model, made from a two-level system modified to include the topology of the energy landscape, is able to capture either a glass transition or a crystallization depending on cooling rate. In this setup, the minimal cooling speed to achieve glass formation is then found to be related with the relaxation time and with the thermal history. In particular, we obtain that the thermal history encodes small fluctuations around the equilibrium population which are exponentially amplified near the glass transition, which mathematically corresponds to the boundary layer of the master equation. Finally, to verify our analytical results, a kinetic Monte-Carlo simulation was implemented.

  6. Dynamic crack initiation toughness : experiments and peridynamic modeling.

    SciTech Connect (OSTI)

    Foster, John T.

    2009-10-01

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

  7. STRUCTURAL VALIDATION OF SYSTEM DYNAMICS AND AGENT-BASED SIMULATION MODELS

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    , population dynamics, energy systems, and urban planning. The usefulness of these models is predicated including global warming, population dynamics, energy systems, and urban planning simply defy a face

  8. Free energy and molecular dynamics calculations for the cubic-tetragonal phase transition in zirconia

    E-Print Network [OSTI]

    Paxton, Anthony T.

    in zirconia Stefano Fabris,* Anthony T. Paxton, and Michael W. Finnis Atomistic Simulation Group, Department zirconia is studied by molecu- lar dynamics MD simulations and within the framework of the Landau theory solutions of zirconia (ZrO2) with cubic stabilizing oxides like Y2O3, MgO or CeO, and are generally called

  9. Intricate phase diagram of a prevalent visual circuit reveals universal dynamics, phase transitions, and resonances

    E-Print Network [OSTI]

    Wessel, Ralf

    for performing specific signal-processing tasks 1­3 . One prevalent connec- tivity pattern found among neural con- trol a network's dynamics and signal-processing carry funda- mental implications for our c feedback triad a b c FIG. 1. Color Neural feedback triads. a In mammals, retinal ganglion cell RGC

  10. Phase transition free regions in the Ising model via the Kac-Ward operator

    E-Print Network [OSTI]

    Marcin Lis

    2015-05-17

    We investigate the spectral radius and operator norm of the Kac-Ward transition matrix for the Ising model on a general planar graph. We then use the obtained results to identify regions in the complex plane where the free energy density limits are analytic functions of the inverse temperature. The bound turns out to be optimal in the case of isoradial graphs, i.e. it yields criticality of the self-dual Z-invariant coupling constants.

  11. Flow regime transitions in dense non-Brownian suspensions: rheology, microstructural characterisation and constitutive modelling

    E-Print Network [OSTI]

    Christopher Ness; Jin Sun

    2014-12-11

    Shear flow of dense, non-Brownian suspensions is simulated using the discrete element method, taking particle contact and hydrodynamic lubrication into account. The resulting flow regimes are mapped in the parametric space of solid volume fraction, shear rate, fluid viscosity and particle stiffness. Below a critical volume fraction $\\phi_c$, the rheology is governed by the Stokes number, which distinguishes between viscous and inertial flow regimes. Above $\\phi_c$, a quasistatic regime exists for low and moderate shear rates. At very high shear rates, the $\\phi$ dependence is lost and soft particle rheology is explored. The transitions between rheological regimes are associated with the evolving contribution of lubrication to the suspension stress. Transitions in microscopic phenomena such as inter-particle force distribution, fabric and correlation length are found to correspond to those in the macroscopic flow. Motivated by the bulk rheology, a constitutive model is proposed combining a viscous pressure term with a dry granular model presented by Chialvo, Sun and Sundaresan [Phys. Rev. E. \\textbf{85}, 021305 (2012)]. The model is shown to successfully capture the flow regime transitions.

  12. Dynamics of a Simple Model for Turbulence of the Second Sound in Helium II

    E-Print Network [OSTI]

    B. V. Chirikov; V. G. Davidovsky

    2000-06-13

    The results of numerical experiments on chaotic ('turbulent') dynamics of the second sound in helium II are presented and discussed based on a very simple model proposed and theoretically studied recently by Khalatnikov and Kroyter. Using a powerful present-day techniques for the studying nonlinear phenomena, we confirm their results on the stationary oscillation in helium and its stability as well as on a qualitative picture of successive transitions to limit cycles and chaos. However, the experiments revealed also a much more complicated structure of the bifurcations than it was expected. The fractal structure of chaotic attractors was also studied including their noninteger dimension. Surprisingly, a very simple model used in all these studies not only qualitatively represents the behavior of helium in laboratory experiments but also allows for a correct order-of-magnitude estimate of the critical heat pumping into helium at bifurcations.

  13. Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction

    E-Print Network [OSTI]

    Veatch, Michael H.

    of approximating functions for the differential cost. The first contribution of this paper is identifying new or piece-wise quadratic. Fluid cost has been used to initialize the value iteration algorithm [5Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction Michael H

  14. Counterclockwise Dynamics of a Rate-Independent Semilinear Duhem Model

    E-Print Network [OSTI]

    Bernstein, Dennis S.

    Counterclockwise Dynamics of a Rate-Independent Semilinear Duhem Model Ashwani K. Padthe, Jin of a hysteretic simple closed curve. In magnetics, hysteresis caused by the irreversible flux-change mechanism dissipates energy in the form of heat [2]. In both cases, the energy dissipated in one cycle is equal

  15. Dynamic and Static Influence Models on Starbucks Networks Minkyoung Kim

    E-Print Network [OSTI]

    Dynamic and Static Influence Models on Starbucks Networks Minkyoung Kim Interdisciplinary Program Starbucks stores in Korea, which have been spread most rapidly in the world, as an exemplary social network for Starbucks to open the 100th store in Korea, which is the fastest growth of Starbucks in the world [10

  16. GLOBAL DYNAMICS OF AN SEIR EPIDEMIC MODEL WITH VERTICAL TRANSMISSION

    E-Print Network [OSTI]

    Li, Michael

    GLOBAL DYNAMICS OF AN SEIR EPIDEMIC MODEL WITH VERTICAL TRANSMISSION MICHAEL Y. LI, HAL L. SMITH population through both horizontal and vertical transmission. The total host population is assumed to have at an endemic equilibrium state if it initially exists. The contribution of the vertical transmission

  17. Modeling Combined Time-and Event-Driven Dynamic Systems

    E-Print Network [OSTI]

    Baclawski, Kenneth B.

    such as logistical systems, distributed sensor sys- tems and intelligent highway vehicle systems, are complex dynamic. In this approach, future behaviors are generated through quantitative simulation which "executes" a simulation model, typically at fixed time steps, to obtain quantitative values of state and/or output variables. 1

  18. Multiscale modeling of polystyrene dynamics in different environments

    E-Print Network [OSTI]

    Faller, Roland

    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

  19. Geographical Information Systems and Dynamic Modeling via Agent Based Systems

    E-Print Network [OSTI]

    de Figueiredo, Luiz Henrique

    Geographical Information Systems and Dynamic Modeling via Agent Based Systems Cláudio Antônio da fariasol@eng.uerj.br ABSTRACT A full integration among Geographical Information Systems and Agent Based integrated with Geographical Information Systems (GIS). The first one is the movement of pedestrians

  20. Modelling microbial population dynamics in nitritation processes Elisabetta Giusti a

    E-Print Network [OSTI]

    Modelling microbial population dynamics in nitritation processes Elisabetta Giusti a , Stefano. Marta 3, I-50139 Florence, Italy b ENEA, Italian National Agency for New Technologies, Energy January 2011 Accepted 1 February 2011 Available online 3 March 2011 Keywords: Microbial kinetics Activated

  1. Lessons Learned from Quantitative Dynamical Modeling in Systems Biology

    E-Print Network [OSTI]

    Timmer, Jens

    Lessons Learned from Quantitative Dynamical Modeling in Systems Biology Andreas Raue1,2 *. , Marcel of Physics, University of Freiburg, Freiburg, Germany, 2 Institute of Computational Biology, Helmholtz Center, Munich, Germany, 3 Systems Biology of Signal Transduction, German Cancer Research Center

  2. Transport coefficients of a mesoscopic fluid dynamics model

    E-Print Network [OSTI]

    N. Kikuchi; C. M. Pooley; J. F. Ryder; J. M. Yeomans

    2003-02-21

    We investigate the properties of stochastic rotation dynamics (Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating hydrodynamics. Analytical results are given for the transport coefficients. We discuss the most efficient way of measuring the transport properties and obtain excellent agreement between the theoretical and numerical calculations.

  3. Parameterized Model Order Reduction of Nonlinear Dynamical Systems

    E-Print Network [OSTI]

    Reif, Rafael

    Parameterized Model Order Reduction of Nonlinear Dynamical Systems Brad Bond Research Laboratory reduction technique for non-linear systems. Our approach combines an existing non-parameterized trajectory piecewise linear method for non-linear systems, with an existing moment matching param- eterized technique

  4. Modeling the Dynamic Interaction of Hebbian and Homeostatic Plasticity

    E-Print Network [OSTI]

    Stryker, Michael

    Neuron Article Modeling the Dynamic Interaction of Hebbian and Homeostatic Plasticity Taro.toyoizumi@brain.riken.jp http://dx.doi.org/10.1016/j.neuron.2014.09.036 SUMMARY Hebbian and homeostatic plasticity together of plasticity directly modifies synaptic strength. Equilibrium is reached when the two are inducing equal

  5. Modelling of the static and dynamic mechanical properties of human

    E-Print Network [OSTI]

    Haslwanter, Thomas

    Modelling of the static and dynamic mechanical properties of human otoliths DISSERTATION zur of the city of Paris #12;#12;Abstract The aim of this study is a numerical investigation of the static in the inner ears. They sense accelerations of the head. In the static case, information retrieved from them

  6. Dynamic Modelling and Control Design of Pre-combustion Power

    E-Print Network [OSTI]

    Foss, Bjarne A.

    principles. The pre- combustion gas power cycle plants consist of reformers and separation units, com and control design of two pre-combustion power cycles, i.e., a hydro- gen membrane reformer (HMR) based power- pressors, gas and steam turbines and a heat recovery system. Analysis of dynamic models at an early stage

  7. Dynamical Model of Rocket Propellant Loading with Liquid Hydrogen

    E-Print Network [OSTI]

    Muratov, Cyrill

    when liquid hydrogen is moved from a storage tank to an external tank via a transfer line. By employingDynamical Model of Rocket Propellant Loading with Liquid Hydrogen Viatcheslav V. Osipov MCT, Inc­evaporation of hydrogen, pressurization of the tanks, and liquid hydrogen and hydrogen vaporflows inthe presence

  8. Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction

    E-Print Network [OSTI]

    McGovern, Amy

    Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction Amy McGovern1 dis- covery methods for use on mesoscale weather data. Severe weather phenomena such as tornados, thun, current techniques for predicting severe weather are tied to specific characteristics of the radar systems

  9. From quantum to classical dynamics: The relativistic $O(N)$ model in the framework of the real-time functional renormalization group

    E-Print Network [OSTI]

    David Mesterházy; Jan H. Stockemer; Yuya Tanizaki

    2015-07-23

    We investigate the transition from unitary to dissipative dynamics in the relativistic $O(N)$ vector model with the $\\lambda (\\varphi^{2})^{2}$ interaction using the nonperturbative functional renormalization group in the real-time formalism. In thermal equilibrium, the theory is characterized by two scales, the interaction range for coherent scattering of particles and the mean free path determined by the rate of incoherent collisions with excitations in the thermal medium. Their competition determines the renormalization group flow and the effective dynamics of the model. Here we quantify the dynamic properties of the model in terms of the scale-dependent dynamic critical exponent $z$ in the limit of large temperatures and in $2 \\leq d \\leq 4$ spatial dimensions. We contrast our results to the behavior expected at vanishing temperature and address the question of the appropriate dynamic universality class for the given microscopic theory.

  10. SO(1,1) dark energy model and the universe transition

    E-Print Network [OSTI]

    Yi-Huan Wei; Yu Tian

    2004-09-18

    We suggest a scalar model of dark energy with the SO(1,1) symmetry. The model may be reformulated in terms of a real scalar field $\\Phi$ and the scale factor $a$ so that the Lagrangian may be decomposed as that of the real quintessence model plus the negative coupling energy term of $\\Phi$ to $a$. The existence of the coupling term $L^c$ leads to a wider range of $w_{\\Phi}$ and overcomes the problem of negative kinetic energy in the phantom universe model. We propose a power-law expansion model of univese with time-dependent power, which can describe the phantom universe and the universe transition from ordinary acceleration to super acceleration.

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

    SciTech Connect (OSTI)

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

    2014-07-28

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

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

    SciTech Connect (OSTI)

    Gasenzer, Thomas [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); McLerran, Larry [Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center and Physics Dept.; China Central Normal Univ., Wuhan (China). Physics Dept.; Pawlowski, Jan M. [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI); Sexty, Dénes [Heidelberg Univ. (Germany). Inst. for Theoretische Physik; GSI-Darmstadt (Germany). ExtreMe Matter Inst. (EMMI)

    2014-10-01

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

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

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

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

    2014-07-28

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

  14. Doppler-Free Spectroscopy of Weak Transitions: An Analytical Model Applied to Formaldehyde

    E-Print Network [OSTI]

    Zeppenfeld, M; Pinkse, P W H; Rempe, G

    2007-01-01

    Experimental observation of Doppler-free signals for weak transitions can be greatly facilitated by an estimate for the expected amplitude of the signal. We derive an analytical model which allows the Doppler-free signal amplitude to be estimated for small Doppler-free signals. Application of this model to formaldehyde allows the amplitude of experimentally observed Doppler-free signals to be reproduced to within a factor of two and the relative amplitude of different lines to be reproduced to within a few percent.

  15. On the modelling of spur and helical gear dynamic behaviour

    E-Print Network [OSTI]

    Velex, Philippe

    2012-01-01

    This chapter is aimed at introducing the fundamentals of spur and helical gear dynamics. Using three-dimensional lumped models and a thin-slice approach for mesh elasticity, the general equations of motion for single-stage spur or helical gears are presented. Some particular cases including the classic one degree-of-freedom model are examined in order to introduce and illustrate the basic phenomena. The interest of the concept of transmission errors is analysed and a number of practical considerations are deduced. Emphasis is deliberately placed on analytical results which, although approximate, allow a clearer understanding of gear dynamics than that provided by extensive numerical simulations. Some extensions towards continuous models are presented.

  16. Mathematical Modeling of Microbial Community Dynamics: A Methodological Review

    SciTech Connect (OSTI)

    Song, Hyun-Seob; Cannon, William R.; Beliaev, Alex S.; Konopka, Allan

    2014-10-17

    Microorganisms in nature form diverse communities that dynamically change in structure and function in response to environmental variations. As a complex adaptive system, microbial communities show higher-order properties that are not present in individual microbes, but arise from their interactions. Predictive mathematical models not only help to understand the underlying principles of the dynamics and emergent properties of natural and synthetic microbial communities, but also provide key knowledge required for engineering them. In this article, we provide an overview of mathematical tools that include not only current mainstream approaches, but also less traditional approaches that, in our opinion, can be potentially useful. We discuss a broad range of methods ranging from low-resolution supra-organismal to high-resolution individual-based modeling. Particularly, we highlight the integrative approaches that synergistically combine disparate methods. In conclusion, we provide our outlook for the key aspects that should be further developed to move microbial community modeling towards greater predictive power.

  17. Gaussian Process Model for Collision Dynamics of Complex Molecules

    E-Print Network [OSTI]

    Cui, Jie

    2015-01-01

    We show that a Gaussian Process model can be combined with a small number of scattering calculations to provide an accurate multi-dimensional dependence of scattering observables on the experimentally controllable parameters (such as the collision energy, temperature or external fields) as well as the potential energy surface parameters. This can be used for solving the inverse scattering problem, the prediction of collision properties of a specific molecular system based on the information for another molecule, the efficient calculation of thermally averaged observables and for reducing the error of the molecular dynamics calculations by averaging over the potential energy surface variations. We show that, trained by a combination of classical and quantum dynamics calculations, the model provides an accurate description of the scattering cross sections, even near scattering resonances. In this case, the classical calculations stabilize the model against uncertainties arising from wildly varying correlations ...

  18. Sensitivity analysis of a dynamic model for submerged arc silicon furnaces.

    E-Print Network [OSTI]

    Foss, Bjarne A.

    Sensitivity analysis of a dynamic model for submerged arc silicon furnaces. B. F. Lund1 , B. A for a dynamic model of submerged arc silicon furnaces. The model we study, called "Simod", was developed updating a nonlinear, dynamic model of a silicon furnace. We have identified a parameter set that has

  19. Model for dynamic self-assembled magnetic surface structures.

    SciTech Connect (OSTI)

    Belkin, M.; Glatz, A.; Snezhko, A.; Aranson, I. S.; Materials Science Division; Northwestern Univ.

    2010-07-07

    We propose a first-principles model for the dynamic self-assembly of magnetic structures at a water-air interface reported in earlier experiments. The model is based on the Navier-Stokes equation for liquids in shallow water approximation coupled to Newton equations for interacting magnetic particles suspended at a water-air interface. The model reproduces most of the observed phenomenology, including spontaneous formation of magnetic snakelike structures, generation of large-scale vortex flows, complex ferromagnetic-antiferromagnetic ordering of the snake, and self-propulsion of bead-snake hybrids.

  20. Stochastic dynamics of small ensembles of non-processive molecular motors: The parallel cluster model

    SciTech Connect (OSTI)

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

    2013-11-07

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

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

    E-Print Network [OSTI]

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

    2013-10-17

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

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

    SciTech Connect (OSTI)

    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

    2008-01-01

    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.

  3. Modeling a fluid to solid phase transition in snow weak-layers. Application to slab avalanche release

    E-Print Network [OSTI]

    Francois Louchet

    2015-04-07

    Snow slab avalanche release usually results from failure of weak layers made of loose ice crystals. In previous field experiments, we evidenced for the first time an interesting stress-driven transition in the weak layer between a granular fluid and a solid phase. We propose here an original model involving the kinetics of ice grains bonds failure and reconstruction. The model evidences a sudden transition between two drastically different types of weak layer behaviors. It accounts for the characteristics of both the studied fluid-solid transition and for slab avalanche release observations. It may possibly apply to a number of other granular materials.

  4. Model of a deterministic detector and dynamical decoherence

    SciTech Connect (OSTI)

    Lee, Jae Weon; Shepelyansky, Dima L. [Laboratoire de Physique Theorique, UMR 5152 du CNRS, Univ. P. Sabatier, 31062 Toulouse Cedex 4 (France); Averin, Dmitri V. [Department of Physics, University of Stony Brook, SUNY, Stony Brook, New York 11794 (United States); Benenti, Giuliano [Center for Nonlinear and Complex Systems, Universita degli Studi dell'Insubria and Istituto Nazionale per la Fisica della Materia, Unita di Como, Via Valleggio 11, 22100 Como (Italy)

    2005-07-15

    We discuss a deterministic model of detector coupled to a two-level system (a qubit). The detector is a quasiclassical object whose dynamics is described by the kicked rotator Hamiltonian. We show that in the regime of quantum chaos the detector acts as a chaotic bath and induces decoherence of the qubit. We discuss the dephasing and relaxation rates and demonstrate that the main features of single-qubit decoherence due to a heat bath can be reproduced by our fully deterministic dynamical model. Moreover, we show that, for strong enough qubit-detector coupling, the dephasing rate is given by the rate of exponential instability of the detector's dynamics, that is, by the Lyapunov exponent of classical motion. Finally, we discuss the measurement in the regimes of strong and weak qubit-detector coupling. For the case of strong coupling the detector performs a measurement of the up/down state of the qubit. In the case of weak coupling, due to chaos, the dynamical evolution of the detector is strongly sensitive to the state of the qubit. However, in this case it is unclear how to extract a signal from any measurement with a coarse-graining in the phase space on a size much larger than the Planck cell.

  5. Keratin Dynamics: Modeling the Interplay between Turnover and Transport

    E-Print Network [OSTI]

    Stephanie Portet; Anotida Madzvamuse; Andy Chung; Rudolf E. Leube; Reinhard Windoffer

    2015-04-01

    Keratin are among the most abundant proteins in epithelial cells. Functions of the keratin network in cells are shaped by their dynamical organization. Using a collection of experimentally-driven mathematical models, different hypotheses for the turnover and transport of the keratin material in epithelial cells are tested. The interplay between turnover and transport and their effects on the keratin organization in cells are hence investigated by combining mathematical modeling and experimental data. Amongst the collection of mathematical models considered, a best model strongly supported by experimental data is identified. Fundamental to this approach is the fact that optimal parameter values associated with the best fit for each model are established. The best candidate among the best fits is characterized by the disassembly of the assembled keratin material in the perinuclear region and an active transport of the assembled keratin. Our study shows that an active transport of the assembled keratin is required to explain the experimentally observed keratin organization.

  6. Multi-resolution modeling of the dynamic loading of metal matrix...

    Office of Scientific and Technical Information (OSTI)

    Multi-resolution modeling of the dynamic loading of metal matrix composites. Citation Details In-Document Search Title: Multi-resolution modeling of the dynamic loading of metal...

  7. Dynamic ModelingDynamic Modeling the Electric Power Networkthe Electric Power Network

    E-Print Network [OSTI]

    Oro, Daniel

    at the National Energy Modeling System/Annual Energy Outlook Conference, Washington, DC, March 10, 2003] #12

  8. On preparation of viscous pore fluids for dynamic centrifuge modelling

    E-Print Network [OSTI]

    Adamidis, O.; Madabhushi, S. P. G.

    2014-11-21

    upon cooling. Gelation temperatures for METHOCEL F50 are well above the expected range of temperatures in dynamic centrifuge modelling [Dow, 2002]. As a result, the gelation process is not consid- ered in this study. Measurements of viscosity... + e e · ki (24) where k is the coefficient of permeability and i is the hydraulic gradient. Since an upper estimate for shearing rate is sought after, the critical hydraulic gradient, for which the seepage forces become equal to the submerged weight...

  9. A human breast cell model of pre-invasive to invasive transition

    SciTech Connect (OSTI)

    Bissell, Mina J; Rizki, Aylin; Weaver, Valerie M.; Lee, Sun-Young; Rozenberg, Gabriela I.; Chin, Koei; Myers, Connie A.; Bascom, Jamie L.; Mott, Joni D.; Semeiks, Jeremy R.; Grate, Leslie R.; Mian, I. Saira; Borowsky, Alexander D.; Jensen, Roy A.; Idowu, Michael O.; Chen, Fanqing; Chen, David J.; Petersen, Ole W.; Gray, Joe W.; Bissell, Mina J.

    2008-03-10

    A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher grade tumors. To find functionally significant changes in transition from pre-invasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between pre-invasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP-9,-13,-15,-17 was up regulated in the invasive cells. Using siRNA based approaches, we found these MMPs to be required for the invasive phenotype. This model provides a new tool for dissection of mechanisms by which pre-invasive breast cells could acquire invasiveness in a metaplastic context.

  10. Block entropy and quantum phase transition in the anisotropic Kondo necklace model

    SciTech Connect (OSTI)

    Mendoza-Arenas, J. J.; Franco, R.; Silva-Valencia, J.

    2010-06-15

    We study the von Neumann block entropy in the Kondo necklace model for different anisotropies {eta} in the XY interaction between conduction spins using the density matrix renormalization group method. It was found that the block entropy presents a maximum for each {eta} considered, and, comparing it with the results of the quantum criticality of the model based on the behavior of the energy gap, we observe that the maximum block entropy occurs at the quantum critical point between an antiferromagnetic and a Kondo singlet state, so this measure of entanglement is useful for giving information about where a quantum phase transition occurs in this model. We observe that the block entropy also presents a maximum at the quantum critical points that are obtained when an anisotropy {Delta} is included in the Kondo exchange between localized and conduction spins; when {Delta} diminishes for a fixed value of {eta}, the critical point increases, favoring the antiferromagnetic phase.

  11. Introducing a new 3D dynamical model for barred galaxies

    E-Print Network [OSTI]

    Jung, Christof

    2015-01-01

    The regular or chaotic dynamics of an analytical realistic three dimensional model composed of a spherically symmetric central nucleus, a bar and a flat disk is investigated. For describing the properties of the bar we introduce a new simple dynamical model and we explore the influence on the character of orbits of all the involved parameters of it, such as the mass and the scale length of the bar, the major semi-axis and the angular velocity of the bar as well as the energy. Regions of phase space with ordered and chaotic motion are identified in dependence on these parameters and for breaking the rotational symmetry. First we study in detail the dynamics in the invariant plane $z = p_z = 0$ using the Poincar\\'e map as a basic tool and then we study the full 3 dimensional case using the SALI method as principal tool for distinguishing between order and chaos. We also present strong evidence obtained through the numerical simulations that our new bar model can realistically describe the formation and the evol...

  12. Interacting cosmic fluids and phase transitions under a holographic modeling for dark energy

    E-Print Network [OSTI]

    Samuel Lepe; Francisco Pena

    2015-11-23

    We discuss the consequences of possible sign changes of the $Q$-function which measures the energy transference between dark energy and dark matter. We investigate this scenario from a holographic perspective to modeling the dark energy by a linear-parametrization of the equation of state parameter denoted by $\\omega$. By imposing the strong constraint of the second law of thermodynamics, we show that sign changes of $Q$ due to the cosmic evolution imply changes in the temperatures of dark energy and dark matter, respectively. We also discuss the phase transitions, in the past and future, experienced by dark energy and dark matter (or, equivalently, the sign changes of their heat capacities).

  13. Interacting cosmic fluids and phase transitions under a holographic modeling for dark energy

    E-Print Network [OSTI]

    Lepe, Samuel

    2015-01-01

    We discuss the consequences of possible sign changes of the $Q$-function which measures the energy transference between dark energy and dark matter. We investigate this scenario from a holographic perspective to modeling the dark energy by a linear-parametrization of the equation of state parameter denoted by $\\omega$. By imposing the strong constraint of the second law of thermodynamics, we show that sign changes of $Q$ due to the cosmic evolution imply changes in the temperatures of dark energy and dark matter, respectively. We also discuss the phase transitions, in the past and future, experienced by dark energy and dark matter (or, equivalently, the sign changes of their heat capacities).

  14. Modeling the Potential Effects of New Tobacco Products and Policies: A Dynamic Population Model for Multiple Product Use and Harm

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

    Vugrin, Eric D.; Rostron, Brian L.; Verzi, Stephen J.; Brodsky, Nancy S.; Brown, Theresa J.; Choiniere, Conrad J.; Coleman, Blair N.; Paredes, Antonio; Apelberg, Benjamin J.

    2015-03-27

    Background Recent declines in US cigarette smoking prevalence have coincided with increases in use of other tobacco products. Multiple product tobacco models can help assess the population health impacts associated with use of a wide range of tobacco products. Methods and Findings We present a multi-state, dynamical systems population structure model that can be used to assess the effects of tobacco product use behaviors on population health. The model incorporates transition behaviors, such as initiation, cessation, switching, and dual use, related to the use of multiple products. The model tracks product use prevalence and mortality attributable to tobacco use formore »the overall population and by sex and age group. The model can also be used to estimate differences in these outcomes between scenarios by varying input parameter values. We demonstrate model capabilities by projecting future cigarette smoking prevalence and smoking-attributable mortality and then simulating the effects of introduction of a hypothetical new lower-risk tobacco product under a variety of assumptions about product use. Sensitivity analyses were conducted to examine the range of population impacts that could occur due to differences in input values for product use and risk. We demonstrate that potential benefits from cigarette smokers switching to the lower-risk product can be offset over time through increased initiation of this product. Model results show that population health benefits are particularly sensitive to product risks and initiation, switching, and dual use behaviors. Conclusion Our model incorporates the variety of tobacco use behaviors and risks that occur with multiple products. As such, it can evaluate the population health impacts associated with the introduction of new tobacco products or policies that may result in product switching or dual use. Further model development will include refinement of data inputs for non-cigarette tobacco products and inclusion of health outcomes such as morbidity and disability.« less

  15. Nuclear Hybrid Energy System Modeling: RELAP5 Dynamic Coupling Capabilities

    SciTech Connect (OSTI)

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

    2012-09-01

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

  16. CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING

    E-Print Network [OSTI]

    CREATING DYNAMIC EQUIVALENT PV CIRCUIT MODELS WITH IMPEDANCE SPECTROSCOPY FOR ARC FAULT MODELING ® (NEC® ) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc of the arcing frequencies through PV components despite the potential for modules and other PV components

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

    E-Print Network [OSTI]

    Bath, University of

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

  18. User Guide for PV Dynamic Model Simulation Written on PSCAD Platform

    SciTech Connect (OSTI)

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

    2014-11-01

    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.

  19. Use dynamic simulation to model HPU reactor depressuring

    SciTech Connect (OSTI)

    Ernest, J.B.; Depew, C.A. (Fluor Daniel, Inc., Irvine, CA (United States))

    1995-01-01

    Dynamic simulation is the best available method for the analysis of hydroprocessing unit (HPU) depressuring. Depressuring is crucial for the safe operation of hydrocracking and other HPUs with catalysts that have hydrocracking activity. Effective design for depressuring is valuable for all types of HPUs, both grass-roots and revamps. Reactor loop depressuring can set design temperatures and pressures for the reactor effluent cooling train and other equipment and piping in an HPU. Unfortunately, usual methods for determining equipment and piping design conditions during depressuring leave much room for improvement because they poorly account for time-dependent temperature and pressure changes. Dynamic simulation makes it practical to more accurately estimate these transient conditions. The paper discusses depressuring design, including the nature of depressuring, the impact of depressuring on design, and depressuring calculation methods. The author then describes modeling of hydroprocessing unit depressuring by discussing the general and particular correspondence of simulation modules to physical equipment using the base case of total electrical power failure. The special data that is required for dynamic simulation is described and typical simulation results are given. Lastly, the advantages of dynamic simulation are summarized.

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

    SciTech Connect (OSTI)

    Burkett, Michael W; Clancy, Sean P

    2009-01-01

    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.

  1. A transferable coarse-grained model for diphenylalanine: How to represent an environment driven conformational transition

    SciTech Connect (OSTI)

    Dalgicdir, Cahit; Sensoy, Ozge; Sayar, Mehmet, E-mail: msayar@ku.edu.tr [College of Engineering, Koç University, 34450 Istanbul (Turkey)] [College of Engineering, Koç University, 34450 Istanbul (Turkey); Peter, Christine [Max Planck Institute for Polymer Research, 55128 Mainz (Germany) [Max Planck Institute for Polymer Research, 55128 Mainz (Germany); Department of Chemistry, University of Konstanz, 78547 Konstanz (Germany)

    2013-12-21

    One of the major challenges in the development of coarse grained (CG) simulation models that aim at biomolecular structure formation processes is the correct representation of an environment-driven conformational change, for example, a folding/unfolding event upon interaction with an interface or upon aggregation. In the present study, we investigate this transferability challenge for a CG model using the example of diphenylalanine. This dipeptide displays a transition from a trans-like to a cis-like conformation upon aggregation as well as upon transfer from bulk water to the cyclohexane/water interface. Here, we show that one can construct a single CG model that can reproduce both the bulk and interface conformational behavior and the segregation between hydrophobic/hydrophilic medium. While the general strategy to obtain nonbonded interactions in the present CG model is to reproduce solvation free energies of small molecules representing the CG beads in the respective solvents, the success of the model strongly depends on nontrivial decisions one has to make to capture the delicate balance between the bonded and nonbonded interactions. In particular, we found that the peptide's conformational behavior is qualitatively affected by the cyclohexane/water interaction potential, an interaction that does not directly involve the peptide at all but merely influences the properties of the hydrophobic/hydrophilic interface. Furthermore, we show that a small modification to improve the structural/conformational properties of the CG model could dramatically alter the thermodynamic properties.

  2. Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics

    SciTech Connect (OSTI)

    Persson, Rasmus A. X.; Chu, Jhih-Wei, E-mail: jwchu@nctu.edu.tw [Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Voulgarakis, Nikolaos K. [Department of Mathematics, Washington State University, Richland, Washington 99372 (United States)

    2014-11-07

    Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ? in coupling to the other equations of FHD. The resulting ?-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ?-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ?-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 Å, the ?-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.

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

    SciTech Connect (OSTI)

    Rokkam, Ram

    2012-11-02

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

  4. Solvability via viscosity solutions for a model of phase transitions driven by configurational forces

    E-Print Network [OSTI]

    Zhu, Peicheng

    2009-01-01

    In the present article, we are interested in an initial boundary value problem for a coupled system of partial differential equations arising in martensitic phase transition theory of elastically deformable solid materials, e.g., steel. This model was proposed and investigated in previous work by Alber and Zhu in which the weak solutions are defined in a standard way, however the key technique is not applicable to multi-dimensional problem. Intending to solve this multi-dimensional problem and to investigate the sharp interface limits of our models, we thus define weak solutions in a different way by using the notion of viscosity solution, then prove the existence of weak solutions to this problem in one space dimension, yet the multi-dimensional problem is still open.

  5. Dynamic Decision Making for Graphical Models Applied to Oil Exploration

    E-Print Network [OSTI]

    Martinelli, Gabriele; Hauge, Ragnar

    2012-01-01

    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.

  6. Kav ci c, Moura, IEEE Transactions on Magnetics, vol. 32, pp. 3875-3877, September 1996. i Expedient Media Noise Modeling: Isolated and Interacting Transitions

    E-Print Network [OSTI]

    Kavcic, Aleksandar

    Expedient Media Noise Modeling: Isolated and Interacting Transitions Aleksandar Kav#20;ci#19;c and Jos#19;e. Introduction There is renewed interest in #12;nding expedient media noise models. Micromagnetic modeling [1], [2] is probably the most accurate model for media (transition) noise. Although accu- rate

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

    E-Print Network [OSTI]

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

    2011-11-11

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

  8. Analysis of the noise-induced bursting-spiking transition in a pancreatic -cell model Jacobo Aguirre,1

    E-Print Network [OSTI]

    Rey Juan Carlos, Universidad

    Analysis of the noise-induced bursting-spiking transition in a pancreatic -cell model Jacobo (Received 15 September 2003; published 30 April 2004) A stochastic model of the electrophysiological embedded in a noisy environment. The analysis is focused on the distortion that a growing noise causes

  9. Entanglement dynamics in a model tripartite quantum system

    E-Print Network [OSTI]

    Pradip Laha; B. Sudarsan; S. Lakshmibala; V. Balakrishnan

    2015-09-23

    A system comprising a $\\Lambda$-type or V-type atom interacting with two radiation fields exhibits, during its dynamical evolution, interesting optical phenomena such as electromagnetically-induced transparency (EIT) and a variety of nonclassical effects. Signatures of the latter are seen in the entanglement dynamics of the atomic subsystem and in appropriate field observables. Some of these effects have been experimentally detected, and have even been used to change the nonlinear optical properties of certain atomic media. It is therefore useful to investigate the roles played by specific initial states of the radiation fields, detuning parameters, field nonlinearities and the nature of field-atom couplings on EIT and on the entanglement between subsystems. We investigate these aspects in the framework of a simple model that captures the salient features of such tripartite entangled systems. Entanglement dynamics is shown to be very sensitive to the intensity-dependent atom-field couplings. Unexpected interesting features pertaining to the collapses and revivals of the atomic subsystem von Neumann entropy appear. These features could, in principle, be useful in enabling entanglement.

  10. A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES

    E-Print Network [OSTI]

    Barth, Eric J.

    A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES Mark the mass flow, piston dynamics, and control volume behavior inside a free-piston Stirling engine. A new model for a Stirling engine thermal regenerator that incorporates a dynamically changing temperature

  11. Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky

    E-Print Network [OSTI]

    Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky Department of Chemistry, Poland Received 22 October 2003; accepted 26 January 2004 Polymer dynamics at large fields in Rubinstein simple exclusion models are used to analyze the reptation dynamics of polymers. It is found

  12. A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu

    E-Print Network [OSTI]

    A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu , Anthony E. Brockwell to as a dynamic supply-demand model, to simultaneously capture electricity price and usage time series. This model, and Duane J. Seppi Abstract We introduce a new model for electricity prices, based on the principle

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

    E-Print Network [OSTI]

    Levine, Alex J.

    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

  14. Spatially Heterogeneous Dynamics and Dynamic Facilitation in a Model of Viscous Silica Michael Vogel* and Sharon C. Glotzer

    E-Print Network [OSTI]

    Weeks, Eric R.

    this behavior. The mode coupling theory [1] describes many aspects of dynamical behavior at high T is not only relevant in spin models [26], but also in a viscous equilibrium liquid. Finally, we show is still the understanding of the tremen- dous slowing down of molecular dynamics in supercooled liquids

  15. Impact of subgrid-scale radiative heating variability on the stratocumulus-to-trade cumulus transition in climate models

    SciTech Connect (OSTI)

    Xiao, Heng; Gustafson, William I.; Wang, Hailong

    2014-04-29

    Subgrid-scale interactions between turbulence and radiation are potentially important for accurately reproducing marine low clouds in climate models. To better understand the impact of these interactions, the Weather Research and Forecasting (WRF) model is configured for large eddy simulation (LES) to study the stratocumulus-to-trade cumulus (Sc-to-Cu) transition. Using the GEWEX Atmospheric System Studies (GASS) composite Lagrangian transition case and the Atlantic Trade Wind Experiment (ATEX) case, it is shown that the lack of subgrid-scale turbulence-radiation interaction, as is the case in current generation climate models, accelerates the Sc-to-Cu transition. Our analysis suggests that in cloud-topped boundary layers subgrid-scale turbulence-radiation interactions contribute to stronger production of temperature variance, which in turn leads to stronger buoyancy production of turbulent kinetic energy and helps to maintain the Sc cover.

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

    SciTech Connect (OSTI)

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

    1993-09-01

    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.

  17. Entanglement dynamics for the double Tavis-Cummings model

    E-Print Network [OSTI]

    Zhong-Xiao Man; Yun-Jie Xia; Nguyen Ba An

    2009-02-14

    A double Tavis-Cummings model (DTCM) is developed to simulate the entanglement dynamics of realistic quantum information processing where two entangled atom-pairs $AB$ and $CD$ are distributed in such a way that atoms $AC$ are embedded in a cavity $a$ while $BD$ are located in another remote cavity $b$. The evolutions of different types of initially shared entanglement of atoms are studied under various initial states of cavity fields. The results obtained in the DTCM are compared with that obtained in the double Jaynes-Cummings model (DJCM) [J. Phys. B \\textbf{40}, S45 (2007)] and an interaction strength theory is proposed to explain the parameter domain in which the so-called entanglement sudden death occurs for both the DTCM and DJCM.

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

    E-Print Network [OSTI]

    Lynch, Nancy

    and gates, steam boiler control) appear in [8, 10]. Briefly, a timed automaton is a labelled transition

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

    E-Print Network [OSTI]

    Lynch, Nancy

    and gates, steam boiler control) appear in 8, 10]. Brie y, a timed automaton is a labelled transition system

  20. New methods for estimation, modeling and validation of dynamical systems using automatic differentiation 

    E-Print Network [OSTI]

    Griffith, Daniel Todd

    2005-02-17

    The main objective of this work is to demonstrate some new computational methods for estimation, optimization and modeling of dynamical systems that use automatic differentiation. Particular focus will be upon dynamical ...

  1. Computational Model of Population Dynamics Based on the Cell Cycle and Local Interactions

    SciTech Connect (OSTI)

    Oprisan, Sorinel Adrian; Oprisan, Ana

    2005-03-31

    Our study bridges cellular (mesoscopic) level interactions and global population (macroscopic) dynamics of carcinoma. The morphological differences and transitions between well and smooth defined benign tumors and tentacular malignat tumors suggest a theoretical analysis of tumor invasion based on the development of mathematical models exhibiting bifurcations of spatial patterns in the density of tumor cells. Our computational model views the most representative and clinically relevant features of oncogenesis as a fight between two distinct sub-systems: the immune system of the host and the neoplastic system. We implemented the neoplastic sub-system using a three-stage cell cycle: active, dormant, and necrosis. The second considered sub-system consists of cytotoxic active (effector) cells -- EC, with a very broad phenotype ranging from NK cells to CTL cells, macrophages, etc. Based on extensive numerical simulations, we correlated the fractal dimensions for carcinoma, which could be obtained from tumor imaging, with the malignat stage. Our computational model was able to also simulate the effects of surgical, chemotherapeutical, and radiotherapeutical treatments.

  2. Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics

    SciTech Connect (OSTI)

    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)

    2012-01-01

    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.

  3. Parameter Estimation of Dynamic Air-conditioning Component Models Using Limited Sensor Data 

    E-Print Network [OSTI]

    Hariharan, Natarajkumar

    2011-08-08

    This thesis presents an approach for identifying critical model parameters in dynamic air-conditioning systems using limited sensor information. The expansion valve model and the compressor model parameters play a crucial ...

  4. DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE/DIVINYLBENZENE

    E-Print Network [OSTI]

    Schittkowski, Klaus

    DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE model for the living anionic solution polymerization of styrene/butadiene/divinylbenzene in a continuous kinetic reactor model for the living anionic solution polymerization of styrene/butadiene

  5. VISION -- A Dynamic Model of the Nuclear Fuel Cycle

    SciTech Connect (OSTI)

    J. J. Jacobson; A. M. Yacout; S. J. Piet; D. E. Shropshire; G. E. Matthern

    2006-02-01

    The Advanced Fuel Cycle Initiative’s (AFCI) fundamental objective is to provide technology options that – if implemented – would enable long-term growth of nuclear power while improving sustainability and energy security. The AFCI organization structure consists of four areas; Systems Analysis, Fuels, Separations and Transmutations. The Systems Analysis Working Group is tasked with bridging the program technical areas and providing the models, tools, and analyses required to assess the feasibility of design and deploy¬ment options and inform key decision makers. An integral part of the Systems Analysis tool set is the development of a system level model that can be used to examine the implications of the different mixes of reactors, implications of fuel reprocessing, impact of deployment technologies, as well as potential “exit” or “off ramp” approaches to phase out technologies, waste management issues and long-term repository needs. The Verifiable Fuel Cycle Simulation Model (VISION) is a computer-based simulation model that allows performing dynamic simulations of fuel cycles to quantify infrastructure requirements and identify key trade-offs between alternatives. VISION is intended to serve as a broad systems analysis and study tool applicable to work conducted as part of the AFCI (including costs estimates) and Generation IV reactor development studies.

  6. Transition to chaos in random neuronal networks

    E-Print Network [OSTI]

    Jonathan Kadmon; Haim Sompolinsky

    2015-08-26

    Firing patterns in the central nervous system often exhibit strong temporal irregularity and heterogeneity in their time averaged response properties. Previous studies suggested that these properties are outcome of an intrinsic chaotic dynamics. Indeed, simplified rate-based large neuronal networks with random synaptic connections are known to exhibit sharp transition from fixed point to chaotic dynamics when the synaptic gain is increased. However, the existence of a similar transition in neuronal circuit models with more realistic architectures and firing dynamics has not been established. In this work we investigate rate based dynamics of neuronal circuits composed of several subpopulations and random connectivity. Nonzero connections are either positive-for excitatory neurons, or negative for inhibitory ones, while single neuron output is strictly positive; in line with known constraints in many biological systems. Using Dynamic Mean Field Theory, we find the phase diagram depicting the regimes of stable fixed point, unstable dynamic and chaotic rate fluctuations. We characterize the properties of systems near the chaotic transition and show that dilute excitatory-inhibitory architectures exhibit the same onset to chaos as a network with Gaussian connectivity. Interestingly, the critical properties near transition depend on the shape of the single- neuron input-output transfer function near firing threshold. Finally, we investigate network models with spiking dynamics. When synaptic time constants are slow relative to the mean inverse firing rates, the network undergoes a sharp transition from fast spiking fluctuations and static firing rates to a state with slow chaotic rate fluctuations. When the synaptic time constants are finite, the transition becomes smooth and obeys scaling properties, similar to crossover phenomena in statistical mechanics

  7. Minimum of $?/s$ and the phase transition of the Linear Sigma Model in the large-N limit

    E-Print Network [OSTI]

    Antonio Dobado; Felipe J. Llanes-Estrada; Juan M. Torres-Rincon

    2009-12-03

    We reexamine the possibility of employing the viscosity over entropy density ratio as a diagnostic tool to identify a phase transition in hadron physics to the strongly coupled quark-gluon plasma and other circumstances where direct measurement of the order parameter or the free energy may be difficult. It has been conjectured that the minimum of eta/s does indeed occur at the phase transition. We now make a careful assessment in a controled theoretical framework, the Linear Sigma Model at large-N, and indeed find that the minimum of eta/s occurs near the second order phase transition of the model due to the rapid variation of the order parameter (here the sigma vacuum expectation value) at a temperature slightly smaller than the critical one.

  8. Large-scale Environmental Variables and Transition to Deep Convection in Cloud Resolving Model Simulations: A Vector Representation

    SciTech Connect (OSTI)

    Hagos, Samson M.; Leung, Lai-Yung R.

    2012-11-01

    Cloud resolving model simulations and vector analysis are used to develop a quantitative method of assessing regional variations in the relationships between various large-scale environmental variables and the transition to deep convection. Results of the CRM simulations from three tropical regions are used to cluster environmental conditions under which transition to deep convection does and does not take place. Projections of the large-scale environmental variables on the difference between these two clusters are used to quantify the roles of these variables in the transition to deep convection. While the transition to deep convection is most sensitive to moisture and vertical velocity perturbations, the details of the profiles of the anomalies vary from region to region. In comparison, the transition to deep convection is found to be much less sensitive to temperature anomalies over all three regions. The vector formulation presented in this study represents a simple general framework for quantifying various aspects of how the transition to deep convection is sensitive to environmental conditions.

  9. THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL

    E-Print Network [OSTI]

    Lübeck, Sven

    261 THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL L. ROTERS, S. L. The behavior of the model is determined by three parameters, the maximal velocity v max , the noise parameter P of the dynamical structure factor of the Nagel­ Schreckenberg traffic flow model based on the local occupation

  10. Chiral Phase Transition in the Soft-Wall Model of AdS/QCD

    E-Print Network [OSTI]

    Chelabi, Kaddour; Huang, Mei; Li, Danning; Wu, Yue-Liang

    2015-01-01

    We investigate the chiral phase transition in the soft-wall model of AdS/QCD at zero chemical potential for two-flavor and three-flavor cases, respectively. We show that there is no spontaneous chiral symmetry breaking in the original soft-wall model. After detailed analysis, we find that in order to realize chiral symmetry breaking and restoration, both profiles for the scalar potential and the dilaton field are essential. The scalar potential determines the possible solution structure of the chiral condensate, except the mass term, it takes another quartic term for the two-flavor case, and for the three-flavor case, one has to take into account an extra cubic term due to the t'Hooft determinant interaction. The profile of the dilaton field reflects the gluodynamics, which is negative at a certain ultraviolet scale and approaches positive quadratic behavior at far infrared region. With this set-up, the spontaneous chiral symmetry breaking in the vacuum and its restoration at finite temperature can be realize...

  11. THE GREAT OXIDATION OF EARTH'S ATMOSPHERE: CONTESTING THE YOYO MODEL VIA TRANSITION STABILITY ANALYSIS

    SciTech Connect (OSTI)

    Cuntz, M.; Roy, D.; Musielak, Z. E., E-mail: cuntz@uta.ed, E-mail: dipanjan.roy@etumel.univmed.f, E-mail: zmusielak@uta.ed [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2009-11-20

    A significant controversy regarding the climate history of the Earth and its relationship to the development of complex life forms concerns the rise of oxygen in the early Earth's atmosphere. Geological records show that this rise occurred about 2.4 Gyr ago, when the atmospheric oxygen increased from less than 10{sup -5} present atmospheric level (PAL) to more than 0.01 PAL and possibly above 0.1 PAL. However, there is a debate whether this rise happened relatively smoothly or with well-pronounced ups and downs (the Yoyo model). In our study, we explore a simplified atmospheric chemical system consisting of oxygen, methane, and carbon that is driven by the sudden decline of the net input of reductants to the surface as previously considered by Goldblatt et al. Based on the transition stability analysis for the system equations, constituting a set of non-autonomous and non-linear differential equations, as well as the inspection of the Lyapunov exponents, it is found that the equations do not exhibit chaotic behavior. In addition, the rise of oxygen occurs relative smoothly, possibly with minor bumps (within a factor of 1.2), but without major jumps. This result clearly argues against the Yoyo model in agreement with recent geological findings.

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

    E-Print Network [OSTI]

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

    2015-07-24

    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. 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 $SU(2) \\rightarrow U(1)$ 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.

  13. The effect of O{sub 2} intercalation on the rotational dynamics and the ordering transition of C{sub 60}

    SciTech Connect (OSTI)

    Myers, S.A.; Assink, R.A.; Schirber, J.E.; Loy, D.A.

    1995-01-01

    We have used {sup 13}C magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to characterize the structure and rotational dynamics of C{sub 60} containing oxygen molecules located in the interstitial sites of the fcc lattice. Under normal conditions, a narrow peak at 143.7 ppm is observed for C{sub 60}. When exposed to oxygen at moderate pressures, several additional resonances appear in the {sup 13}C MAS NMR spectrum. These secondary resonances are shifted downfield from the main peak at 143.7 ppm and are due to the Fermi-contact interaction of the paramagnetic oxygen molecules with the {sup 13}C nuclear spins. The presence of oxygen depresses the orientational ordering transition by ca. 20 K as observed by DSC. The spin-lattice relaxation time (T{sub 1}) of each secondary peak shows a minimum near the ordering transition, indicating that this transition is not dependent on the number of oxygen molecules surrounding an individual C{sub 60} molecule. The T{sub 1}, due to paramagnetic relaxation, normalized by the number of surrounding oxygen molecules, is constant. This observation demonstrates that within a given sample, the dynamics of C{sub 60} molecules are independent of the number of surrounding oxygen molecules.

  14. Comparing the escape dynamics in tidally limited star cluster models

    E-Print Network [OSTI]

    Euaggelos E. Zotos

    2015-08-21

    The aim of this work is to compare the orbital dynamics in three different models describing the properties of a star cluster rotating around its parent galaxy in a circular orbit. In particular, we use the isochrone and the Hernquist potentials to model the spherically symmetric star cluster and we compare our results with the corresponding ones of a previous work in which the Plummer model was applied for the same purpose. Our analysis takes place both in the configuration $(x,y)$ and in the phase $(x,\\dot{x})$ space in order to elucidate the escape process as well as the overall orbital properties of the tidally limited star cluster. We restrict our investigation into two dimensions and we conduct a thorough numerical analysis distinguishing between ordered and chaotic orbits as well as between trapped and escaping orbits, considering only unbounded motion for several energy levels above the critical escape energy. It is of particular interest to determine the escape basins towards the two exit channels (near the Lagrangian points $L_1$ and $L_2$) and relate them with the corresponding escape times of the orbits.

  15. Comparing the escape dynamics in tidally limited star cluster models

    E-Print Network [OSTI]

    Zotos, Euaggelos E

    2015-01-01

    The aim of this work is to compare the orbital dynamics in three different models describing the properties of a star cluster rotating around its parent galaxy in a circular orbit. In particular, we use the isochrone and the Hernquist potentials to model the spherically symmetric star cluster and we compare our results with the corresponding ones of a previous work in which the Plummer model was applied for the same purpose. Our analysis takes place both in the configuration $(x,y)$ and in the phase $(x,\\dot{x})$ space in order to elucidate the escape process as well as the overall orbital properties of the tidally limited star cluster. We restrict our investigation into two dimensions and we conduct a thorough numerical analysis distinguishing between ordered and chaotic orbits as well as between trapped and escaping orbits, considering only unbounded motion for several energy levels above the critical escape energy. It is of particular interest to determine the escape basins towards the two exit channels (n...

  16. Description of waste pretreatment and interfacing systems dynamic simulation model

    SciTech Connect (OSTI)

    Garbrick, D.J.; Zimmerman, B.D.

    1995-05-01

    The Waste Pretreatment and Interfacing Systems Dynamic Simulation Model was created to investigate the required pretreatment facility processing rates for both high level and low level waste so that the vitrification of tank waste can be completed according to the milestones defined in the Tri-Party Agreement (TPA). In order to achieve this objective, the processes upstream and downstream of the pretreatment facilities must also be included. The simulation model starts with retrieval of tank waste and ends with vitrification for both low level and high level wastes. This report describes the results of three simulation cases: one based on suggested average facility processing rates, one with facility rates determined so that approximately 6 new DSTs are required, and one with facility rates determined so that approximately no new DSTs are required. It appears, based on the simulation results, that reasonable facility processing rates can be selected so that no new DSTs are required by the TWRS program. However, this conclusion must be viewed with respect to the modeling assumptions, described in detail in the report. Also included in the report, in an appendix, are results of two sensitivity cases: one with glass plant water recycle steams recycled versus not recycled, and one employing the TPA SST retrieval schedule versus a more uniform SST retrieval schedule. Both recycling and retrieval schedule appear to have a significant impact on overall tank usage.

  17. Quadrupole collective dynamics from energy density functionals: Collective Hamiltonian and the interacting boson model

    SciTech Connect (OSTI)

    Nomura, K.; Vretenar, D.; Niksic, T.; Otsuka, T.; Shimizu, N.

    2011-07-15

    Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of {sup 192,194,196}Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the {gamma}-vibration bands are compared to the corresponding sequences of experimental states.

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

    E-Print Network [OSTI]

    Xiuli Cen

    2014-08-27

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

  19. Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle material

    E-Print Network [OSTI]

    Microscale and mesoscale discrete models for dynamic fracture of structures built of brittle are derived either at microscale with random distribution of material properties or at a mesoscale

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

    SciTech Connect (OSTI)

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

    2011-06-01

    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.

  1. Probabilistic model identification of the bit-rock-interaction-model uncertainties in nonlinear dynamics of a drill-string

    E-Print Network [OSTI]

    Boyer, Edmond

    , and simple models are usually considered in the analysis. This is an important constraint when uncertaintiesProbabilistic model identification of the bit-rock-interaction-model uncertainties in nonlinear model of uncertainties in a bit-rock interaction model for the nonlinear dynamics of a drill

  2. Mixtures of Predictive Linear Gaussian Models for Nonlinear Stochastic Dynamical Systems

    E-Print Network [OSTI]

    Baveja, Satinder Singh

    Mixtures of Predictive Linear Gaussian Models for Nonlinear Stochastic Dynamical Systems David dynamical systems. The primary contribution of this work is to extend the PLG to nonlinear, stochastic- proves upon traditional linear dynamical system mod- els by using a predictive representation of state

  3. Dynamically Tracking the Strain Across the Metal-Insulator Transition in VO2 Measured Using Electromechanical Resonators

    E-Print Network [OSTI]

    Wu, Junqiao

    Electromechanical Resonators Pritesh Parikh,,, Chitraleema Chakraborty,, T. S. Abhilash, Shamashis Sengupta,*, Chun electromechanical device across the metal-insulator transition. Simultaneous resistance and resonance measurements strain coupled with simultaneous resistance and resonance measurements using electromechanical resonators

  4. The ghosts of departed quantities in switches and transitions

    E-Print Network [OSTI]

    Mike R. Jeffrey

    2015-08-18

    Transitions between steady dynamical regimes in diverse applications are often modelled using discontinuities, but doing so introduces problems of uniqueness. No matter how quickly a transition occurs, its inner workings can affect the dynamics of the system significantly. Here we discuss the way transitions can be reduced to discontinuities without trivializing them, by preserving so-called hidden terms. We review the fundamental methodology, its motivations, and where their study seems to be heading. We derive a prototype for piecewise smooth models from the asymptotics of systems with rapid transitions, extending Filippov's convex combinations by encoding the tails of asymptotic series into nonlinear dependence on a switching parameter. We then explore a few examples illustrating the impact of these on our standard picture of smooth or only piecewise smooth dynamics.

  5. A Dynamic Solar Core model: the SSM-like solution

    E-Print Network [OSTI]

    Attila Grandpierre

    1998-08-31

    I point out that the all the arguments against an astrophysical solution do not exclude a yet not recognised class of solar models, in which an explosive energy source is present in the solar core besides the standard pp and CNO cycle. It is shown from first principle physics that stars have a non-pp,CNO source: local thermonuclear runaways. I derive a model independent inequality, which shows that the problem of the missing beryllium neutrinos lies in that the SuperKamiokande contains a term arising from neutrinos from a runaway source which can produce high-energy electrons and high-energy axions, and muon and tau neutrinos. I point out, that the temperature dependence of the individual neutrino fluxes is related to pure nuclear physics but the usual luminosity constraint is model dependent and actually is a questionable assumption. Allowing non-pp,CNO reaction chains a new approach arises to interpret the neutrino detector data. The explicit temperature dependence leads to $\\Phi_{pp} \\propto T^4$ instead of the usual $\\Phi_{pp} \\propto T^{-1/2}$ for the SSM luminosity constraint. I assume a Sun analogue to the SSM with a different $T_c$. The separate neutrino detector equations lead to separate detector-related temperatures with the neutrino detector data. The results show a slightly lower than standard central temperature. I attempt to show that helioseismology is not in a necessary conflict with the dynamic solar model presented here. The results of the calculations may propose solutions to the problems of solar and atmospheric neutrino oscillations without an ad hoc introduction of sterile neutrinos and present predictions to Borexino and SNO measurements. {\\it PACS numbers}: 26.65+t, 26.30.+k, 96.60Jw, 95.30.Cq

  6. The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells

    SciTech Connect (OSTI)

    Meier, Sebastian B., E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany); Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Hartmann, David; Sarfert, Wiebke, E-mail: sebastian.meier@belectric.com, E-mail: wiebke.sarfert@siemens.com [Siemens AG, Corporate Technology, CT RTC MAT IEC-DE, 91058 Erlangen (Germany); Winnacker, Albrecht [Department of Materials Science VI: Materials for Electronics and Energy Technology, Friedrich-Alexander-University of Erlangen-Nuremberg, 91058 Erlangen (Germany)

    2014-09-14

    Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2´-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy)?(pbpy)][PF?]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage.

  7. A Dynamic Solar Core Model: the Deviant Temperatures Approach

    E-Print Network [OSTI]

    Attila Grandpierre

    1998-08-31

    I derive here a model independent inequality which shows that the problem of the missing beryllium neutrinos of the Sun roots in the fact that the SuperKamiokande contains a term arising from a non-pp,CNO source. First principle physics shows that the non-pp,CNO source is of thermonuclear runaway origin. Several indications suggest that the non-pp,CNO term plays a more significant role in the solar neutrino problems than neutrino oscillations. When removing the over-restricted SSM luminosity constraint, the temperature dependence of the neutrino fluxes is related to pure nuclear physics and follows $\\Phi_{pp} \\propto T^4$ instead of $\\Phi_{pp} \\propto T^{-1/2}$. The results of the calculations offer solutions to the solar neutrino problems and problems of neutrino oscillations. The dynamic solar model presents predictions to Borexino and SNO measurements. These predictions can serve to distinguish between the MSW and the non-pp,CNO effect. {\\it PACS numbers|: 26.65.+t, 26.30.+k, 96.60.JW, 95.30.Cq

  8. The challenges of modelling antibody repertoire dynamics in HIV infection

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

    Luo, Shishi; Perelson, Alan S.

    2015-07-20

    Antibody affinity maturation by somatic hypermutation of B-cell immunoglobulin variable region genes has been studied for decades in various model systems using well-defined antigens. While much is known about the molecular details of the process, our understanding of the selective forces that generate affinity maturation are less well developed, particularly in the case of a co-evolving pathogen such as HIV. Despite this gap in understanding, high-throughput antibody sequence data are increasingly being collected to investigate the evolutionary trajectories of antibody lineages in HIV-infected individuals. Here, we review what is known in controlled experimental systems about the mechanisms underlying antibody selectionmore »and compare this to the observed temporal patterns of antibody evolution in HIV infection. In addition, we describe how our current understanding of antibody selection mechanisms leaves questions about antibody dynamics in HIV infection unanswered. Without a mechanistic understanding of antibody selection in the context of a co-evolving viral population, modelling and analysis of antibody sequences in HIV-infected individuals will be limited in their interpretation and predictive ability.« less

  9. Ultrafast Structural Dynamics in Combustion Relevant Model Systems

    SciTech Connect (OSTI)

    Weber, Peter M.

    2014-03-31

    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

  10. Internal phase transition induced by external forces in Finsler geometric model for membranes

    E-Print Network [OSTI]

    Hiroshi Koibuchi; Andrey Shobukhov

    2015-08-29

    We numerically study an anisotropic shape transformation of membranes under external forces for two-dimensional triangulated surfaces on the basis of Finsler geometry. The Finsler metric is defined by using a vector field, which is the tangential component of a three dimensional unit vector $\\sigma$ corresponding to the tilt or some external macromolecules on the surface of disk topology. The sigma model Hamiltonian is assumed for the tangential component of $\\sigma$ with the interaction coefficient $\\lambda$. For large (small) $\\lambda$, the surface becomes oblong (collapsed) at relatively small bending rigidity. For the intermediate $\\lambda$, the surface becomes planar. Conversely, fixing the surface with the boundary of area $A$ or with the two point boundaries of distance $L$, we find that the variable $\\sigma$ changes from random to aligned state with increasing of $A$ or $L$ for the intermediate region of $\\lambda$. This implies that an internal phase transition for $\\sigma$ is triggered not only by the thermal fluctuations but also by external mechanical forces. We also find that the frame (string) tension shows the expected scaling behavior with respect to $A/N$ ($L/N$) at the intermediate region of $A$ ($L$) where the $\\sigma$ configuration changes between the disordered and ordered phases. Moreover, we find that the string tension $\\gamma$ at sufficiently large $\\lambda$ is considerably smaller than that at small $\\lambda$. This phenomenon resembles the so-called soft-elasticity in the liquid crystal elastomer, which is deformed by small external tensile forces.

  11. MODELING THE ATOMIC-TO-MOLECULAR TRANSITION AND CHEMICAL DISTRIBUTIONS OF TURBULENT STAR-FORMING CLOUDS

    SciTech Connect (OSTI)

    Offner, Stella S. R. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Bisbas, Thomas G.; Viti, Serena [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6B (United Kingdom); Bell, Tom A., E-mail: stella.offner@yale.edu [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, E-28850 Madrid (Spain)

    2013-06-10

    We use 3D-PDR, a three-dimensional astrochemistry code for modeling photodissociation regions (PDRs), to post-process hydrodynamic simulations of turbulent, star-forming clouds. We focus on the transition from atomic to molecular gas, with specific attention to the formation and distribution of H, C{sup +}, C, H{sub 2}, and CO. First, we demonstrate that the details of the cloud chemistry and our conclusions are insensitive to the simulation spatial resolution, to the resolution at the cloud edge, and to the ray angular resolution. We then investigate the effect of geometry and simulation parameters on chemical abundances and find weak dependence on cloud morphology as dictated by gravity and turbulent Mach number. For a uniform external radiation field, we find similar distributions to those derived using a one-dimensional PDR code. However, we demonstrate that a three-dimensional treatment is necessary for a spatially varying external field, and we caution against using one-dimensional treatments for non-symmetric problems. We compare our results with the work of Glover et al., who self-consistently followed the time evolution of molecule formation in hydrodynamic simulations using a reduced chemical network. In general, we find good agreement with this in situ approach for C and CO abundances. However, the temperature and H{sub 2} abundances are discrepant in the boundary regions (A{sub v} {<=} 5), which is due to the different number of rays used by the two approaches.

  12. Stochastic model for aerodynamic force dynamics on wind turbine blades in unsteady wind inflow

    E-Print Network [OSTI]

    Luhur, Muhammad Ramzan; Kühn, Martin; Wächter, Matthias

    2015-01-01

    The paper presents a stochastic approach to estimate the aerodynamic forces with local dynamics on wind turbine blades in unsteady wind inflow. This is done by integrating a stochastic model of lift and drag dynamics for an airfoil into the aerodynamic simulation software AeroDyn. The model is added as an alternative to the static table lookup approach in blade element momentum (BEM) wake model used by AeroDyn. The stochastic forces are obtained for a rotor blade element using full field turbulence simulated wind data input and compared with the classical BEM and dynamic stall models for identical conditions. The comparison shows that the stochastic model generates additional extended dynamic response in terms of local force fluctuations. Further, the comparison of statistics between the classical BEM, dynamic stall and stochastic models' results in terms of their increment probability density functions gives consistent results.

  13. AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS

    SciTech Connect (OSTI)

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

    2011-01-01

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

  14. DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE 

    E-Print Network [OSTI]

    Aluko, Obanifemi

    2010-01-16

    This work presents a modeling and control study of a reactive distillation column used for hydrogenation of benzene. A steady state and a dynamic model have been developed to investigate control structures for the column. ...

  15. Modelling of power plant dynamics and uncertainties for robust control synthesis *

    E-Print Network [OSTI]

    Ray, Asok

    , TRAC type models3 have been applied to perform safety analysis of nuclear power plants. However, complex dynamic processes such as fossil and nuclear power plants can be modelled and simulated

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

    E-Print Network [OSTI]

    Kelic, Andjelka, 1972-

    2005-01-01

    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 ...

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

    E-Print Network [OSTI]

    Peter O. Fedichev; Leonid I. Menshikov

    2012-01-30

    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.

  18. Discontinuous non-equilibrium phase transition in a threshold Schloegl model for autocatalysis: Generic two-phase coexistence and metastability

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

    Wang, Chi -Jen; Liu, Da -Jiang; Evans, James W.

    2015-04-28

    Threshold versions of Schloegl’s model on a lattice, which involve autocatalytic creation and spontaneous annihilation of particles, can provide a simple prototype for discontinuous non-equilibrium phase transitions. These models are equivalent to so-called threshold contact processes. A discontinuous transition between populated and vacuum states can occur selecting a threshold of N ? 2 for the minimum number, N, of neighboring particles enabling autocatalytic creation at an empty site. Fundamental open questions remain given the lack of a thermodynamic framework for analysis. For a square lattice with N = 2, we show that phase coexistence occurs not at a unique valuemore »but for a finite range of particle annihilation rate (the natural control parameter). This generic two-phase coexistence also persists when perturbing the model to allow spontaneous particle creation. Such behavior contrasts both the Gibbs phase rule for thermodynamic systems and also previous analysis for this model. We find metastability near the transition corresponding to a non-zero effective line tension, also contrasting previously suggested critical behavior. As a result, mean-field type analysis, extended to treat spatially heterogeneous states, further elucidates model behavior.« less

  19. Data-based Subsystem Identification for Dynamic Model Updating Steven Gillijns and Bart De Moor

    E-Print Network [OSTI]

    Data-based Subsystem Identification for Dynamic Model Updating Steven Gillijns and Bart De Moor-pump example. I. INTRODUCTION Models induced from physical laws and models identified from data are both values. In empirical models, inaccuracies can be due to an inappropriate model class or to bad data

  20. Transition dynamics for Mu acceptor states in Si{sub 1–x}Ge{sub x} alloys

    SciTech Connect (OSTI)

    Jayarathna, G.; Lichti, R. L.; Mengyan, P. W.; Baker, B. B. [Texas Tech University, Lubbock, TX 79409-1051 (United States); Celebi, Y. G. [Istanbul University, Istanbul (Turkey); Carroll, B. R. [Arkansas State University, Jonesboro, AR 72410 (United States); Yonenaga, I. [Institute of Materials Research, Tohoku University (Japan)

    2014-02-21

    We use the longitudinal field muon spin relaxation technique to observe charge-state and site-change transitions of muonium in Si{sub 1–x}Ge{sub x} alloys. In this project, we examine the temperature and magnetic field dependences of the relaxation rates for Si{sub 1–x}Ge{sub x} samples (x = 0.77, 0.81, and 0.84), in the composition range where the acceptor level lies within the band gap. This study particularly focuses on the relaxation rates for Si{sub 0.19}Ge{sub 0.81} to identify various cyclic charge-state and site-change processes as a function of both temperature and magnetic field. We extract the paramagnetic hyperfine constant and the relevant transition rate parameters for site changes and charge-state transitions involving Mu acceptor states for this sample. At small x, a site change dominates the transition out of the neutral T-site acceptor state, while in higher Ge content alloys hole ionization becomes the dominant transition out of the Mu{sub T}{sup 0}.

  1. Topological characterization of the transition from laminar regime to fully developed turbulence in the resistive pressure-gradient-driven turbulence model

    SciTech Connect (OSTI)

    Garcia, L.; Carreras, B. A.; Llerena, I.; Calvo, I. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes, Madrid (Spain); Departament d'Algebra i Geometria, Facultat de Matematiques, Universitat de Barcelona, Barcelona (Spain); Laboratorio Nacional de Fusion, Asociacion EURATOM-CIEMAT, 28040 Madrid (Spain)

    2009-10-15

    For the resistive pressure-gradient-driven turbulence model, the transition from laminar regime to fully developed turbulence is not simple and goes through several phases. For low values of the plasma parameter {beta}, a single quasicoherent structure forms. As {beta} increases, several of these structures may emerge and in turn take the dominant role. Finally, at high {beta}, fully developed turbulence with a broad spectrum is established. A suitable characterization of this transition can be given in terms of topological properties of the flow. Here, we analyze these properties that provide an understanding of the turbulence-induced transport and give a measure of the breaking of the homogeneity of the turbulence. To this end, an approach is developed that allows discriminating between topological properties of plasma turbulence flows that are relevant to the transport dynamics and the ones that are not. This is done using computational homology tools and leads to a faster convergence of numerical results for a fixed level of resolution than previously presented in Phys. Rev. E 78, 066402 (2008)

  2. Modeling dynamic crack propagation in fiber reinforced composites including frictional effects q

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    Modeling dynamic crack propagation in fiber reinforced composites including frictional effects q S Abstract Dynamic crack propagation in a unidirectional carbon/epoxy composite is studied through finite deformation anisotropic visco-plastic model is used to describe the constitutive response of the composite

  3. DATA COLLECTION FOR DEVELOPING A DYNAMIC MODEL OF A LIGHT HELICOPTER

    E-Print Network [OSTI]

    DATA COLLECTION FOR DEVELOPING A DYNAMIC MODEL OF A LIGHT HELICOPTER Stefano Geluardi 1,2 , Frank for Biological Cybernetics the influence of an augmented system on helicopter pilots with limited flight skills are necessary to identify the helicopter dynamic model. The mathematical and technical tools used to reach

  4. Modelling Desert Dune Fields Based on Discrete Dynamics STEVEN R. BISHOPa,

    E-Print Network [OSTI]

    Carretero, Ricardo

    Modelling Desert Dune Fields Based on Discrete Dynamics STEVEN R. BISHOPa, *, HIROSHI MOMIJIb is developed to model the dynamics of sand dunes. The physical processes display strong non-linearity that has features we monitor morphology, dune growth, dune migration and spatial patterns within a dune field

  5. Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive Computing

    E-Print Network [OSTI]

    Dang, Zhe

    Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive. Targeting at modeling the high-level dynamics of pervasive comput- ing systems, we introduce Bond Computing are regular, and study their computation power and verification problems. Among other results, we show

  6. FORMAL SEMANTICS AND VERIFICATION OF DYNAMIC RELIABILITY BLOCK DIAGRAMS FOR SYSTEM RELIABILITY MODELING

    E-Print Network [OSTI]

    Xu, Haiping

    that DRBD provides a powerful tool for system reliability modeling, and our proposed verification approachFORMAL SEMANTICS AND VERIFICATION OF DYNAMIC RELIABILITY BLOCK DIAGRAMS FOR SYSTEM RELIABILITY-scale computer-based systems. KEY WORDS Reliability modeling, dynamic reliability block diagrams (DRBD), Object

  7. Aalborg Universitet Dynamic Modeling of a Reformed Methanol Fuel Cell System using Empirical Data and

    E-Print Network [OSTI]

    Berning, Torsten

    Aalborg Universitet Dynamic Modeling of a Reformed Methanol Fuel Cell System using Empirical Data Reza Published in: Journal of Fuel Cell Science and Technology DOI (link to publication from Publisher. K., Andreasen, S. J., & Shaker, H. R. (2014). Dynamic Modeling of a Reformed Methanol Fuel Cell

  8. GLOBAL STABILITY FOR A VIRUS DYNAMICS MODEL WITH NONLINEAR INCIDENCE OF INFECTION AND REMOVAL

    E-Print Network [OSTI]

    GLOBAL STABILITY FOR A VIRUS DYNAMICS MODEL WITH NONLINEAR INCIDENCE OF INFECTION AND REMOVAL PAUL GEORGESCU AND YING-HEN HSIEH Abstract. Global dynamics of a compartmental model which describes virus and the removal rate of the virus are assumed to be nonlinear. In the case where the functional quotient between

  9. An Efficiency Measure for Dynamic Networks Modeled as Evolutionary Variational Inequalities with Application to the Internet

    E-Print Network [OSTI]

    Nagurney, Anna

    An Efficiency Measure for Dynamic Networks Modeled as Evolutionary Variational Inequalities propose an efficiency/performance measure for dynamic net- works, which have been modeled as evolutionary and their rankings. We provide both continuous time and discrete time versions of the efficiency measure. We

  10. Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod

    E-Print Network [OSTI]

    Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod Uluc. Saranli1 , Alfred A. Rizzi1 on the design of a model-based controller that can achieve dynamical self-righting of a hexapod robot. Extending hexapod robot that negotiates badly irregular terrain at speeds better than one body length per second [12

  11. Understanding Collective Crowd Behaviors: Learning a Mixture Model of Dynamic Pedestrian-Agents

    E-Print Network [OSTI]

    Wang, Xiaogang

    Understanding Collective Crowd Behaviors: Learning a Mixture Model of Dynamic Pedestrian@ee.cuhk.edu.hk, xtang@ie.cuhk.edu.hk Abstract In this paper, a new Mixture model of Dynamic pedestrian-Agents (MDA) is proposed to learn the collective behavior patterns of pedestrians in crowded scenes. Col- lective behaviors

  12. Order, chaos and nuclear dynamics: An introduction

    SciTech Connect (OSTI)

    Swiatecki, W.J.

    1990-08-01

    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.

  13. Asynchronous-Transition HMM 

    E-Print Network [OSTI]

    Matsuda, Shigeki; Nakai, Mitsuru; Shimodaira, Hiroshi; Sagayama, Shigeki

    We propose a new class of hidden Markov model (HMM) called asynchronous-transition HMM (AT-HMM). Opposed to conventional HMMs where hidden state transition occurs simultaneously to all features, the new class of HMM allows ...

  14. A two transition state model for radical-molecule reactions : applications to isomeric branching in the OH-isoprene reaction.

    SciTech Connect (OSTI)

    Greenwald, E. E.; North, S. W.; Georgievskii, Y.; Klippenstein, S. J.; Chemistry; Texas A&M Univ.; SNL

    2007-06-28

    A two transition state model is applied to the prediction of the isomeric branching in the addition of hydroxyl radical to isoprene. The outer transition state is treated with phase space theory fitted to long-range transition state theory calculations on an electrostatic potential energy surface. High-level quantum chemical estimates are applied to the treatment of the inner transition state. A one-dimensional master equation based on an analytic reduction from two-dimensions for a particular statistical assumption about the rotational part of the energy transfer kernel is employed in the calculation of the pressure dependence of the addition process. We find that an accurate treatment of the two separate transition state regions, at the energy and angular momentum resolved level, is essential to the prediction of the temperature dependence of the addition rate. The transition from a dominant outer transition state to a dominant inner transition state is shown to occur at about 275 K, with significant effects from both transition states over the 30-500 K temperature range. Modest adjustments in the ab initio predicted inner saddle point energies yield predictions that are in quantitative agreement with the available high-pressure limit experimental observations and qualitative agreement with those in the falloff regime. The theoretically predicted capture rate is reproduced to within 10% by the expression [1.71 x 10-10(T/298)-2.58 exp(-608.6/RT) + 5.47 x 10-11(T/298)-1.78 exp(-97.3/RT); with R = 1.987 and T in K] cm3 molecule-1 s-1 over the 30-500 K range. A 300 K branching ratio of 0.67:0.02:0.02:0.29 was determined for formation of the four possible OH-isoprene adduct isomers 1, 2, 3, and 4, respectively, and was found to be relatively insensitive to temperature. An Arrhenius activation energy of -0.77 kcal/mol was determined for the high-pressure addition rate constants around 300 K.

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

    E-Print Network [OSTI]

    Formosa, Fabien

    2013-01-01

    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...

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

    SciTech Connect (OSTI)

    Krakauer, Henry; Zhang, Shiwei

    2013-02-21

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

  17. Detection and Dynamics of Transiting Exoplanets Proceedings of Haute Provence Observatory Colloquium (23-27 August 2010)

    E-Print Network [OSTI]

    Pinfield, David J.

    Network and of the WTS consortium 1 Centre for Astrophysics Research, University of Hertfordshire [b. The WFCAM Transit Survey (WTS) has been obtain- ing data on the United Kingdom Infrared Telescope since 2007. The WTS targets about 8,000 M dwarfs over several square degrees of sky, and aims to find low

  18. PHYSICAL REVIEW B 86, 144527 (2012) Signatures of the superfluid to Mott insulator transition in equilibrium and in dynamical ramps

    E-Print Network [OSTI]

    Demler, Eugene

    2012-01-01

    32306, USA 5 QUANTOP, Danish Quantum Optics Center and Niels Bohr Institute, DK-2100 Copenhagen Ø with a characteristic universal power law scaling, which is dominated by long wavelength excitations. We calculate received a lot of theoretical attention is ramping a system across a phase transition.4,5 The classical

  19. On the modeling and simulation of reaction-transfer dynamics in semiconductor-electrolyte solar cells

    E-Print Network [OSTI]

    Ren, Kui

    On the modeling and simulation of reaction-transfer dynamics in semiconductor-electrolyte solar-performance semiconductor-liquid junction solar cells. We propose in this work a macroscopic mathematical model, a sys- tem-liquid junction, solar cell simulation, naso-scale device modeling. 1 Introduction The mathematical modeling

  20. 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

  1. Springtime transitions of NO2, CO, and O3 over North America: Model evaluation and analysis

    E-Print Network [OSTI]

    Chance, Kelly

    . The solar input energizes photochemical and meteorological process- es directly by increasing radical and dynamical conditions of the atmosphere. These changes are driven primarily by increasing solar insolation

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

    SciTech Connect (OSTI)

    JACKSON VL

    2011-08-31

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

  3. Critical point symmetries in boson-fermion systems. The case of shape transition in odd nuclei in a multi-orbit model

    E-Print Network [OSTI]

    C. E. Alonso; J. M. Arias; A. Vitturi

    2007-01-08

    We investigate phase transitions in boson-fermion systems. We propose an analytically solvable model (E(5/12)) to describe odd nuclei at the critical point in the transition from the spherical to $\\gamma$-unstable behaviour. In the model, a boson core described within the Bohr Hamiltonian interacts with an unpaired particle assumed to be moving in the three single particle orbitals j=1/2,3/2,5/2. Energy spectra and electromagnetic transitions at the critical point compare well with the results obtained within the Interacting Boson Fermion Model, with a boson-fermion Hamiltonian that describes the same physical situation.

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

    E-Print Network [OSTI]

    Markakis, Michail

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

  5. Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics

    E-Print Network [OSTI]

    Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics

  6. Quantum phase transitions of the Dirac oscillator in the Anti-Snyder model

    E-Print Network [OSTI]

    Presilla, M; Roy, P

    2015-01-01

    We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within the Anti-Snyder modified uncertainty relation characterized by a momentum cut-off ($p\\leq p_{\\text{max}}=1/ \\sqrt{\\beta}$). In ordinary quantum mechanics ($\\beta\\to 0$) this system is known to have a single left-right chiral quantum phase transition (QPT). We show that a finite momentum cut-off modifies the spectrum introducing additional quantum phase transitions. It is also shown that the presence of momentum cut-off modifies the degeneracy of the states.

  7. Quantum phase transitions of the Dirac oscillator in the Anti-Snyder model

    E-Print Network [OSTI]

    M. Presilla; O. Panella; P. Roy

    2015-07-23

    We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within the Anti-Snyder modified uncertainty relation characterized by a momentum cut-off ($p\\leq p_{\\text{max}}=1/ \\sqrt{\\beta}$). In ordinary quantum mechanics ($\\beta\\to 0$) this system is known to have a single left-right chiral quantum phase transition (QPT). We show that a finite momentum cut-off modifies the spectrum introducing additional quantum phase transitions. It is also shown that the presence of momentum cut-off modifies the degeneracy of the states.

  8. Insulator/metal phase transition and colossal magnetoresistance in holographic model

    E-Print Network [OSTI]

    Rong-Gen Cai; Run-Qiu Yang

    2015-07-27

    Within massive gravity, we construct a gravity dual for insulator/metal phase transition and colossal magnetoresistance (CMR) effect found in some manganese oxides materials. In heavy graviton limit, a remarkable magnetic-field-sensitive DC resistivity peak appears at the Curie temperature, where an insulator/metal phase transition happens and the magnetoresistance is scaled with the square of field-induced magnetization. We find that metallic and insulating phases coexist below the Curie point and the relation with the electronic phase separation is discussed.

  9. Algorithms for passive dynamical modeling and passive circuit realizations

    E-Print Network [OSTI]

    Mahmood, Zohaib

    2015-01-01

    The design of modern electronic systems is based on extensive numerical simulations, aimed at predicting the overall system performance and compliance since early design stages. Such simulations rely on accurate dynamical ...

  10. Modeling the dynamics and depositional patterns of sandy rivers

    E-Print Network [OSTI]

    Jerolmack, Douglas J

    2006-01-01

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

  11. Dynamic reduced order modeling of entrained flow gasifiers

    E-Print Network [OSTI]

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

    2010-01-01

    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 ...

  12. Advancing understanding of affect labeling with dynamic causal modeling

    E-Print Network [OSTI]

    Torrisi, SJ; Lieberman, MD; Bookheimer, SY; Altshuler, LL

    2013-01-01

    K.J. , Harrison, L. , Penny, W.D. , 2003. Dynamic causalNeuroimage 22, 1157–1172. Penny, W.D. , Stephan, K.E. ,emotions. Emotion 12, 229–235. Penny, W.D. , 2012. Comparing

  13. Improved Modeling of Transition Metals, Applications to Catalysis and Technetium Chemistry

    SciTech Connect (OSTI)

    Cundari, T. R.

    2004-03-05

    There is considerable impetus for identification of aqueous OM catalysts as water is the ultimate ''green'' solvent. In collaboration with researchers at Ames Lab, we investigated effective fragment and Monte Carlo techniques for aqueous-phase hydroformylation (HyF). The Rh of the HyF catalyst is weakly aquated, in contrast to the hydride of the Rh-H bond. As the insertion of the olefin C=C into Rh-H determines the linear-to-branched aldehyde ratio, it is reasonable to infer that solvent plays an important role in regiochemistry. Studies on aqueous-phase organometallic catalysis were complemented in studies of the gas-phase reaction. A Rh-carbonyl-phosphine catalyst was investigated. Two of the most important implications of this research include (a) pseudorotation among five-coordinate intermediates is significant in HyF, and (b) CO insertion is the rate-determining step. The latter is in contrast to experimental deductions, highlighting the need for more accurate modeling. To this end, we undertook studies of (a) experimentally relevant PR{sub 3} co-ligands (PMe{sub 3}, PPh{sub 3}, P(p-PhSO{sub 3{sup -}}){sub 3}, etc.), and (b) HyF of propene. For the propylene research, simulations indicated that the linear: branched aldehyde ratio (linear is more desirable) is determined by thermodynamic discrimination of two distinct pathways. Other projects include a theory-experiment study of C-H activation by early transition metal systems, which establishes that weakly-bound adducts play a key role in activity selectivity. By extension, more selective catalysts for functionalization of methane (major component of natural gas) will require better understanding of these adducts, which are greatly affected by steric interactions with the ligands. In the de novo design of Tc complexes, we constructed (and are now testing) a coupled quantum mechanics-molecular mechanics protocol. Initial research shows it to be capable of accurately predicting structure ''from scratch.'' Challenges include conformational, geometric, coordination, spin, and particularly linkage (e.g., Tc-SCN versus Tc-NCS) isomerism. In general, our protocol can rapidly (<1 day with desktop software/hardware) predict the structure of diverse Tc complexes with an accuracy commensurate to organics. Our de novo strategy is also being used to investigate tris-pyrazolyl borate (Tp) complexes. Data suggests a fundamental difference in methane activation between TpRe and related CpRe complexes. Furthermore, Tp is a more electronically ''flexible'' platform for catalysts modification than Cp.

  14. RAPID MIXING OF GLAUBER DYNAMICS OF GIBBS ENSEMBLES VIA AGGREGATE PATH COUPLING AND LARGE DEVIATIONS METHODS

    E-Print Network [OSTI]

    Kovchegov, Yevgeniy

    discontinuous phase transitions which have traditionally been more difficult to analyze rigorously is the relationship between the mixing times of the dynamics and the equilibrium phase transition structure, second-order, phase transition, was one of the first models studied to investigate this relation- ship

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

    E-Print Network [OSTI]

    Guang-Hua Zhang; Wei-Zhou Jiang

    2013-02-14

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

  16. Modeling the dynamic component of the geoid and topography of Venus

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    Modeling the dynamic component of the geoid and topography of Venus M. Pauer,1,2 K. Fleming,3 and O. [1] We analyze the Venusian geoid and topography to determine the relative importance of isostatic is whole mantle in style, (2) the long-wavelength geoid and topography are of purely dynamic origin, and (3

  17. Static and dynamic length scales in a simple glassy plaquette model Robert L. Jack,1

    E-Print Network [OSTI]

    Berthier, Ludovic

    Static and dynamic length scales in a simple glassy plaquette model Robert L. Jack,1 Ludovic manuscript received 6 April 2005; published 5 July 2005 We study static and dynamic spatial correlations representation where spins are mapped to plaquette variables. We study the interplay between nontrivial static

  18. Dynamic Modeling of Behavior Change H. T. Banks, Keri L. Rehm, Karyn L. Sutton

    E-Print Network [OSTI]

    for investigating dynamic behavior change. While the approach is applicable to behavior change in eating disorders, smoking, substance abuse and other behavioral disorders, here we present our novel dynamical systems modeling approach to understand the processes governing an individual's behavior in the context of problem

  19. Industry Dynamics: Foundations For Models with an Infinite Number of Firms

    E-Print Network [OSTI]

    Van Roy, Ben

    Industry Dynamics: Foundations For Models with an Infinite Number of Firms Gabriel Y. Weintraub August, 2010 Abstract This paper explores the connection between three important threads of economic research offering different approaches to studying the dynamics of an industry with heterogeneous firms

  20. Low-dimensional models of subcritical transition to turbulence Jeffrey S. Baggetta)

    E-Print Network [OSTI]

    Trefethen, Nick

    Institute of Physics. S1070-6631 97 00304-8 I. INTRODUCTION Certain laminar fluid flows undergo transition is as fol- lows. For any fixed R, it is true that no infinitesimal pertur- bation of the laminar flow can, making laminar flows at high Reynolds numbers in practice unstable, since even the most careful

  1. Oral English development and its impact on emergent reading achievement: a comparative study of transitional bilingual and structured english immersion models 

    E-Print Network [OSTI]

    Tong, Fuhui

    2009-05-15

    This quantitative study derived from an on-going federal experimental research project targeting Spanish-speaking English language learners (ELLs) receiving services in four program models: control/experimental transitional ...

  2. Critical point of gas-liquid type phase transition and phase equilibrium functions in developed two-component plasma model

    SciTech Connect (OSTI)

    Butlitsky, M. A.; Zelener, B. V.

    2014-07-14

    A two-component plasma model, which we called a “shelf Coulomb” model has been developed in this work. A Monte Carlo study has been undertaken to calculate equations of state, pair distribution functions, internal energies, and other thermodynamics properties. A canonical NVT ensemble with periodic boundary conditions was used. The motivation behind the model is also discussed in this work. The “shelf Coulomb” model can be compared to classical two-component (electron-proton) model where charges with zero size interact via a classical Coulomb law. With important difference for interaction of opposite charges: electrons and protons interact via the Coulomb law for large distances between particles, while interaction potential is cut off on small distances. The cut off distance is defined by an arbitrary ? parameter, which depends on system temperature. All the thermodynamics properties of the model depend on dimensionless parameters ? and ? = ?e{sup 2}n{sup 1/3} (where ? = 1/k{sub B}T, n is the particle's density, k{sub B} is the Boltzmann constant, and T is the temperature) only. In addition, it has been shown that the virial theorem works in this model. All the calculations were carried over a wide range of dimensionless ? and ? parameters in order to find the phase transition region, critical point, spinodal, and binodal lines of a model system. The system is observed to undergo a first order gas-liquid type phase transition with the critical point being in the vicinity of ?{sub crit}?13(T{sub crit}{sup *}?0.076),?{sub crit}?1.8(v{sub crit}{sup *}?0.17),P{sub crit}{sup *}?0.39, where specific volume v* = 1/?{sup 3} and reduced temperature T{sup *} = ?{sup ?1}.

  3. Scale and electroweak first-order phase transitions

    E-Print Network [OSTI]

    Jisuke Kubo; Masatoshi Yamada

    2015-09-07

    We consider phase transitions in the standard model (SM) without the Higgs mass term, which is coupled through a Higgs portal term to an SM singlet, classically scale-invariant gauge sector with SM singlet scalar fields. At lower energies the gauge-invariant scalar bilinear in the hidden sector forms a condensate, dynamically creating a robust energy scale, which is transmitted through the Higgs portal term to the SM sector. A scale phase transition is a transition between phases with zero and nonzero condensates. An interplay between the EW and scale phase transitions is therefore expected. We find that in a certain parameter space both the electroweak (EW) and scale phase transitions can be a strong first-order phase transition. The result is obtained by means of an effective theory for the condensation of scalar bilinear in the mean field approximation.

  4. COMPUTERS AND BIOMEDICAL RESEARCH 17, 580-589 ( 1984) Multicompartment Model of Lung Dynamics*

    E-Print Network [OSTI]

    Longtin, André

    COMPUTERS AND BIOMEDICAL RESEARCH 17, 580-589 ( 1984) Multicompartment Model of Lung Dynamics* B of the lungs. The lungs are represented by 24 compartments each corresponding to a generation of the Weibel model A. In the model it is assumed that gases are transported in the lungs by convection and diffusion

  5. Parasitic castration: a perspective from a model of dynamic energy Spencer R. Hall,1,

    E-Print Network [OSTI]

    Hall, Spencer

    of dynamic energy budgets (DEB), we show how these results readily emerge, assuming that parasites consume this model, we compare and contrast two strategies for parasites. ``Consumers'' only steal energy from model of energy flow using a minimal number of assumptions. Finally, the DEB model for both ``consumers

  6. Automated Modeling of Dynamic Reliability Block Diagrams Using Colored Petri Nets

    E-Print Network [OSTI]

    Xu, Haiping

    solution to automated verification of DRBD models. Index Terms--System reliability, reliability block \\ Abstract--Computer system reliability is conventionally modeled and analyzed using techniques such as fault), defines a framework for modeling dynamic reliability behavior of computer-based systems. However

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

    E-Print Network [OSTI]

    Nikolaou, Michael

    1 Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua for identification and validation of an empirical model for a helicon plasma reactor, on the basis of experimental manufacturing processes such as plasma etching, accurate models based on first principles may be developed

  8. Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow

    E-Print Network [OSTI]

    Wang, Chao-Yang

    Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow W-dimensional model is developed to simulate discharge of a primary lithium/thionyl chloride battery. The model to the first task with important examples of lead-acid,1-3 nickel-metal hydride,4-8 and lithium-based batteries

  9. Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models

    E-Print Network [OSTI]

    Sarkar, Sudeep

    Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models Leonid V. Tsap finite element models. The method is based on the iterative analysis of the differences betweenÐPhysically-based vision, deformable models, nonrigid motion analysis, biomedical applications, finite element analysis. æ

  10. Haptics-based Volumetric Modeling Using Dynamic Spline-based Implicit Functions

    E-Print Network [OSTI]

    Qin, Hong

    Haptics-based Volumetric Modeling Using Dynamic Spline-based Implicit Functions Jing Hua Hong Qin-based volumetric modeling framework, which is founded upon volumetric implicit functions and powerful physics-based modeling. The volumetric implicit functions incorporate hierarchical B-splines, CSG-based functional

  11. Modelling vegetation dynamics at global scale due to climate changes: Comparison of two approaches

    SciTech Connect (OSTI)

    Belotelov, N.V.; Bogatyrev, B.G.; Lobanov, A.I.

    1996-12-31

    Climate changes will influence vegetation dynamics. One of the ways of forecasting these changes is the creation of mathematical models describing vegetation dynamics. Computer experiments can then be conducted under climate change scenarios. Two main approaches are used to create such models. The first approach is based on a bioclimatic dynamic approach. The second approach is based on modelling the main eco-physiological processes. The bioclimatic dynamic approach consists of hypotheses about vegetation types or biomes, and their interrelationships with climate. In the eco-physiological approach, a detailed description of the processes, such as production, mortality, plants migration and their competition is presented. A number of computer experiments has been conducted for several climatic scenario for Russia and the whole world. A qualitative comparison of the results with the results of an earlier bioclimatic model has been done.

  12. Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites 

    E-Print Network [OSTI]

    Gaddamanugu, Dhatri

    2010-07-14

    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...

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

    E-Print Network [OSTI]

    Rojas Paico, Danny H.

    2001-01-01

    The integration of dynamic data into reservoir models is known as automatic history matching, and it requires the solution of an inverse problem through the minimization of an objective function. The objective function to ...

  14. A scalable computational approach for modeling dynamic fracture of brittle solids in three dimensions

    E-Print Network [OSTI]

    Seagraves, Andrew Nathan

    2010-01-01

    In this thesis a new parallel computational method is proposed for modeling threedimensional dynamic fracture of brittle solids. The method is based on a combination of the discontinuous Galerkin (DG) formulation of the ...

  15. A model simulation of white-winged dove population dynamics in the Tamaulipan Biotic Province 

    E-Print Network [OSTI]

    Martinez, Cristina Ann

    2002-01-01

    I present the development, evaluation, and sensitivity analysis of a simulation model representing two components of population dynamics-natality and mortality-for the white-winged dove (Zenaida asiatica asiatica; WWDO). I also discuss the role...

  16. Dynamic Modeling and Wavelet-Based Multi-Parametric Tuning and Validation for HVAC Systems 

    E-Print Network [OSTI]

    Liang, Shuangshuang

    2014-07-10

    Dynamic Heating, Ventilation, and Air-Conditioning (HVAC) system models are used for the purpose of control design, fault detection and diagnosis, system analysis, design and optimization. Therefore, ensuring the accuracy ...

  17. Dynamical Modeling and Multi-Experiment Fitting with PottersWheel Supplement

    E-Print Network [OSTI]

    Timmer, Jens

    Dynamical Modeling and Multi-Experiment Fitting with PottersWheel ­ Supplement Thomas Maiwald@fdm.uni-freiburg.de June 10, 2008 Abstract This supplement provides detailed information about the functionalities

  18. A Nonlinear Continuous Time Optimal Control Model of Dynamic Pricing and Inventory Control with no

    E-Print Network [OSTI]

    Adida, Elodie

    time optimal control model for studying a dynamic pricing and inventory control problem for a make-to-stock of not introducing any approximation to the real setting: it provides the exact solution of the system. When taking

  19. Dynamic Long-Term Modelling of Generation Capacity Investment and Capacity Margins

    E-Print Network [OSTI]

    Eager, Dan; Hobbs, Benjamin; Bialek, Janusz

    2012-04-25

    is the mix and amount of generation investment over time in response to policies promoting high penetrations of variable output renewable power such as wind. Modelling the dynamics of merchant generation investment in market environments can inform the debate...

  20. THE EMERGENT STRUCTURE OF THE DROSOPHILA WING A Dynamic Model Generator

    E-Print Network [OSTI]

    Abate, Alessandro

    THE EMERGENT STRUCTURE OF THE DROSOPHILA WING A Dynamic Model Generator Alberto Silletti Department packing; 2. then, given a movie (a sequence of frames) of the fly wing, correlate the networks generated

  1. Design of a test apparatus to study a proposed dynamic tissue puncture model

    E-Print Network [OSTI]

    Inman, Kathleen Marie

    2013-01-01

    Two test apparatuses were designed, built, and evaluated in order to study a proposed dynamic tissue puncture model. The test apparatuses were designed to improve existing experiments used previously to experimentally ...

  2. EEGbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts

    E-Print Network [OSTI]

    Roberts, Stephen

    EEG­based communication via dynamic neural network models William D. Penny and Stephen J. Roberts fw.penny, s.j.robertsg@ic.ac.uk Department of Electrical and Electronic Engineering, Imperial College

  3. EEGbased communication via dynamic neural network models William D. Penny and Stephen J. Roberts

    E-Print Network [OSTI]

    Penny, Will

    EEG­based communication via dynamic neural network models William D. Penny and Stephen J. Roberts fw.penny, s.j.robertsg@ic.ac.uk Department of Electrical and Electronic Engineering, Imperial College

  4. Development of a Dynamic DOE Calibration Model | Department of...

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

    model was developed. The model can be applied for calibration and control system optimization. p-22anderson.pdf More Documents & Publications Reducing the Particulate Emission...

  5. Sleep Dynamics and Seizure Control in a Mesoscale Cortical Model

    E-Print Network [OSTI]

    Lopour, Beth Ann

    2009-01-01

    Contributions . . . . . . . . . 2 Mesoscale Cortical Modelstates in h e from the mesoscale cortical model, here- afterand Seizure Control in a Mesoscale Cortical Model by Beth

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

    SciTech Connect (OSTI)

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

    2013-05-01

    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.

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

    SciTech Connect (OSTI)

    Trudnowski, D.J.

    1992-12-01

    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.

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

    SciTech Connect (OSTI)

    Trudnowski, D.J.

    1992-12-01

    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.

  9. A dynamic model for underbalanced drilling with coiled tubing

    SciTech Connect (OSTI)

    Rommetveit, R.; Vefring, E.H.; Wang, Z.; Bieseman, T.; Faure, A.M.

    1995-11-01

    A model for underbalanced drilling with coiled tubing has been developed which takes into account all important factors contributing to the process. This model is a unique tool to plan and execute underbalanced or near balance drilling operations. It is a transient, one-dimensional multi-phase flow model with the following components: Lift gas system model, multiphase hydraulics model, reservoir-wellbore interaction model, drilling model, models for multiphase fluids (lift gas, produced gas, mud, foam, produced gas, oil, water and cuttings). Various alternative geometries for gas injection are modeled as well as all important operations during underbalanced drilling with coiled tubing. The model as well as some simulation results for its use are presented in this paper.

  10. Baryon Transition in Holographic QCD

    E-Print Network [OSTI]

    Si-wen Li

    2015-09-24

    We propose a mechanism of holographic baryon transition in the Sakai-Sugimoto (SS) model: baryons in this model can jump to different states under the mediated effect of gravitons (or glueballs by holography). We consider a time-dependent gravitational perturbation from M5-brane solution of D=11 supergravity and by employing the relations between 11D M-theory and IIA string theory, we get its 10 dimensional counterpart in the SS model. Such a perturbation is received by the D4-branes wrapped on the $S^{4}$ part of the 10D background, namely the baryon vertex. Technically, baryons in the SS model are described by BPST instanton ansatz and their dynamics can be analyzed using the quantum mechanical system in the instanton's moduli space. In this way, different baryonic states are marked by quantum numbers of moduli space quantum mechanics. By holographic spirit, the gravitational perturbation enters the Hamiltonian as a time-dependent perturbation and it is this time-dependent perturbative Hamiltonian produces the transition between different baryonic states. We calculate the transition probability and get the selection rule and also compute the condition for baryon transition and give the possible transition processes in the limit $\\omega\\gg\\left|\\vec{k}\\right|^{2}$. Since in 10D language, the fluctuation from 11D metric are the perturbation of 10D metric and dilaton which are the modes carried by close strings, thus from the string theory point of view, our proposition can be accounted as the baryonic D4 brane jumps to different states by emitting or absorbing close strings coming from the bulk. In the viewpoints of QCD, it could be interpreted as that baryons transform to different states by interacting with glueballs as a low energy effective theory.

  11. Dynamic-Feature Extraction, Attribution and Reconstruction (DEAR) Method for Power System Model Reduction

    SciTech Connect (OSTI)

    Wang, Shaobu; Lu, Shuai; Zhou, Ning; Lin, Guang; Elizondo, Marcelo A.; Pai, M. A.

    2014-09-04

    In interconnected power systems, dynamic model reduction can be applied on generators outside the area of interest to mitigate the computational cost with transient stability studies. This paper presents an approach of deriving the reduced dynamic model of the external area based on dynamic response measurements, which comprises of three steps, dynamic-feature extraction, attribution and reconstruction (DEAR). In the DEAR approach, a feature extraction technique, such as singular value decomposition (SVD), is applied to the measured generator dynamics after a disturbance. Characteristic generators are then identified in the feature attribution step for matching the extracted dynamic features with the highest similarity, forming a suboptimal ‘basis’ of system dynamics. In the reconstruction step, generator state variables such as rotor angles and voltage magnitudes are approximated with a linear combination of the characteristic generators, resulting in a quasi-nonlinear reduced model of the original external system. Network model is un-changed in the DEAR method. Tests on several IEEE standard systems show that the proposed method gets better reduction ratio and response errors than the traditional coherency aggregation methods.

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

    SciTech Connect (OSTI)

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

    2011-01-01

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

  13. Heating-induced transitions to improved confinement regimes in a zero-dimensional model for tokamak plasmas

    E-Print Network [OSTI]

    Zhu, H; Dendy, R O

    2013-01-01

    It is shown that rapid substantial changes in heating rate can induce transitions to improved energy confinement regimes in zero-dimensional models for tokamak plasma phenomenology. We examine the effect of step changes in heating rate in the model of M.A.Malkov and P.H.Diamond, Phys. Plasmas 16, 012504 (2009), which nonlinearly couples the evolving temperature gradient, microturbulence and a mesoscale flow; and in the extension of H.Zhu, S.C.Chapman and R.O.Dendy, Phys. Plasmas 20, 042302 (2013), which couples to a second mesoscale flow component. The temperature gradient rises, as does the confinement time defined by analogy with the fusion context, while microturbulence is suppressed. This outcome is robust against variation of heating rise time and against introduction of an additional variable into the model.

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

    SciTech Connect (OSTI)

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

    2013-08-16

    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.

  15. Cross-over versus first-order phase transition in holographic gravity-single-dilaton models of QCD thermodynamics

    E-Print Network [OSTI]

    R. Yaresko; J. Knaute; B. Kampfer

    2015-03-31

    A dilaton potential is adjusted to recently confirmed lattice QCD thermodynamics data in the temperature range $(0.7 \\ldots 3.5) T_c$ where $T_c = 155 \\text{MeV}$ is the pseudo-critical temperature. The employed holographic model is based on a gravity--single-field dilaton dual. We discuss conditions for enforcing (for the pure gluon plasma) or avoiding (for the QCD quark-gluon plasma) a first-order phase transition, but still keeping a softest point (minimum of sound velocity).

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

    SciTech Connect (OSTI)

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

    2013-03-01

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

  17. Single cell growth and gene expression dynamics in model organisms

    E-Print Network [OSTI]

    Cookson, Natalie Anne

    2009-01-01

    technology, and computational modeling, we can begin to probe and even mimic native network architecture and high-

  18. Effects of density dependent sex allocation on the dynamics of a simultaneous hermaphroditic population: Modelling and analysis

    E-Print Network [OSTI]

    Bravo de la Parra, Rafael

    Effects of density dependent sex allocation on the dynamics of a simultaneous hermaphroditic Available online 22 December 2009 Keywords: Sex-allocation model Sex-structured population dynamics Density model describing the dynamics of a population where sex allocation remains flexible throughout adult

  19. Dynamical systems modeling of Continuous Flash Suppression Daisuke Shimaoka

    E-Print Network [OSTI]

    Kaneko, Kunihiko

    : Binocular rivalry Adaptation Neural modeling a b s t r a c t Continuous Flash Suppression (CFS is considered to be involved in CFS, but does not reproduce CFS. We then extend the model by including of visibility observed in CFS. In addition, this model captured some defining characteristics of CFS

  20. Communication: Ro-vibrational control of chemical reactivity in H+CH{sub 4}? H{sub 2}+CH{sub 3} : Full-dimensional quantum dynamics calculations and a sudden model

    SciTech Connect (OSTI)

    Welsch, Ralph Manthe, Uwe

    2014-08-07

    The mode-selective chemistry of the title reaction is studied by full-dimensional quantum dynamics simulation on an accurate ab initio potential energy surface for vanishing total angular momentum. Using a rigorous transition state based approach and multi-configurational time-dependent Hartree wave packet propagation, initial state-selected reaction probabilities for many ro-vibrational states of methane are calculated. The theoretical results are compared with experimental trends seen in reactions of methane. An intuitive interpretation of the ro-vibrational control of the chemical reactivity provided by a sudden model based on the quantum transition state concept is discussed.

  1. A nonlinear dynamic model of a once-through, helical-coil steam generator

    SciTech Connect (OSTI)

    Abdalla, M.A. [Oak Ridge Inst. for Science and Education, TN (United States)

    1993-07-01

    A dynamic model of a once-through, helical-coil steam generator is presented. The model simulates the advanced liquid metal reactor superheated cycle steam generator with a four-region, moving-boundary, drift-flux model. The model is described by a set of nonlinear differential equations derived from the fundamental equations of conversation of mass, energy, and momentum. Sample results of steady-state and transient calculations are presented.

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

    SciTech Connect (OSTI)

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

    2013-01-01

    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.

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

    E-Print Network [OSTI]

    S. Bondarenko; K. Komoshvili

    2013-10-07

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

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

    SciTech Connect (OSTI)

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

    2007-02-15

    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.

  5. The Dynamics of Subhalos in Warm Dark Matter Models

    E-Print Network [OSTI]

    Alexander Knebe; Bastian Arnold; Chris Power; Brad K. Gibson

    2008-02-12

    We present a comparison of the properties of substructure halos (subhalos) orbiting within host halos that form in Cold Dark Matter (CDM) and Warm Dark Matter (WDM) cosmologies. Our study focuses on selected properties of these subhalos, namely their anisotropic spatial distribution within the hosts; the existence of a "backsplash'' population; the age-distance relation; the degree to which they suffer mass loss; and the distribution of relative (infall) velocities with respect to the hosts. We find that the number density of subhalos in our WDM model is suppressed relative to that in the CDM model, as we would expect. Interestingly, our analysis reveals that backsplash subhalos exist in both the WDM and CDM models. Indeed, there are no statistically significant differences between the spatial distributions of subhalos in the CDM and WDM models. There is evidence that subhalos in the WDM model suffer enhanced mass loss relative to their counterparts in the CDM model, reflecting their lower central densities. We note also a tendency for the (infall) velocities of subhalos in the WDM model to be higher than in the CDM model. Nevertheless, we conclude that observational tests based on either the spatial distribution or the kinematics of the subhalo population are unlikely to help us to differentiate between the CDM model and our adopted WDM model.

  6. Excited-state quantum phase transitions in systems with two degrees of freedom: Level density, level dynamics, thermal properties

    SciTech Connect (OSTI)

    Stránský, Pavel; Macek, Michal; Cejnar, Pavel

    2014-06-15

    Quantum systems with a finite number of freedom degrees f develop robust singularities in the energy spectrum of excited states as the system’s size increases to infinity. We analyze the general form of these singularities for low f, particularly f=2, clarifying the relation to classical stationary points of the corresponding potential. Signatures in the smoothed energy dependence of the quantum state density and in the flow of energy levels with an arbitrary control parameter are described along with the relevant thermodynamical consequences. The general analysis is illustrated with specific examples of excited-state singularities accompanying the first-order quantum phase transition. -- Highlights: •ESQPTs found in infinite-size limit of systems with low numbers of freedom degrees f. •ESQPTs related to non-analytical evolutions of classical phase–space properties. •ESQPT signatures analyzed for general f, particularly f=2, extending known case f=1. •ESQPT signatures identified in smoothened density and flow of energy spectrum. •ESQPTs shown to induce a new type of thermodynamic anomalies.

  7. Methylation patterns and mathematical models reveal dynamics of stem cell turnover in the human colon

    E-Print Network [OSTI]

    renewal while the daughter stem cell remains in the niche; each stem cell is ``immortal'' under this modelCommentary Methylation patterns and mathematical models reveal dynamics of stem cell turnover in diseases such as cancer, it is essential to understand the process of somatic cell development and renewal

  8. Discrete molecular dynamics studies of the folding of a protein-like model

    E-Print Network [OSTI]

    Buldyrev, Sergey

    Discrete molecular dynamics studies of the folding of a protein-like model Nikolay V Dokholyan1 to resolve in time the folding of model proteins in computer simulations. Different computational approaches). Results: We used the recently proposed approach of Zhou and Karplus to study the folding of a protein

  9. Sand dune dynamics and climate change: A modeling H. Yizhaq,1

    E-Print Network [OSTI]

    Ashkenazy, Yossi "Yosef"

    Sand dune dynamics and climate change: A modeling approach H. Yizhaq,1 Y. Ashkenazy,1 and H. Tsoar2] We provide several examples for the coexistence of active and fixed sand dunes under similar climatic conditions, namely, with respect to wind power and precipitation rate. A model is developed for dune

  10. Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive Computing

    E-Print Network [OSTI]

    Dang, Zhe

    Bond Computing Systems: a Biologically Inspired and High-level Dynamics Model for Pervasive their com- putation power and verification problems. Among other results, we show that the computing power) techniques for pervasive computing systems. At a high-level, there are at least two views in modeling

  11. Model-Lite Planning: Diverse Multi-Option Plans & Dynamic Objective Functions Daniel Bryce

    E-Print Network [OSTI]

    Kambhampati, Subbarao

    Model-Lite Planning: Diverse Multi-Option Plans & Dynamic Objective Functions Daniel Bryce}@asu.edu Abstract Knowledge acquisition is one major bottle-neck in using planning systems. Model-lite planning reduces this burden by placing responsibility on the planning system to cope with partially specified

  12. 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

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

    E-Print Network [OSTI]

    Victoria, University of

    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

  14. A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness

    E-Print Network [OSTI]

    O'Leary, Michael

    A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University PDE Seminar Vanderbilt University November 2008 Mike O'Leary (Towson University are joint with Judith Miller, Georgetown University. Mike O'Leary (Towson University) A Diffusion Model

  15. Mehmood et al. Paper No. 03-2158 1 Modeling Car-following Using System Dynamics

    E-Print Network [OSTI]

    Hellinga, Bruce

    Mehmood et al. Paper No. 03-2158 1 Modeling Car-following Using System Dynamics ARIF MEHMOOD, BRUCE2L 3G1, Canada. E-mail: amehmood@uwaterloo.ca Car following models describe driver behavior of relationships that do not correspond to physical aspects of the car- following process. In this paper we

  16. Generalized models as a universal approach to the analysis of nonlinear dynamical systems

    E-Print Network [OSTI]

    Thilo Gross; Ulrike Feudel

    2006-01-29

    We present a universal approach to the investigation of the dynamics in generalized models. In these models the processes that are taken into account are not restricted to specific functional forms. Therefore a single generalized models can describe a class of systems which share a similar structure. Despite this generality, the proposed approach allows us to study the dynamical properties of generalized models efficiently in the framework of local bifurcation theory. The approach is based on a normalization procedure that is used to identify natural parameters of the system. The Jacobian in a steady state is then derived as a function of these parameters. The analytical computation of local bifurcations using computer algebra reveals conditions for the local asymptotic stability of steady states and provides certain insights on the global dynamics of the system. The proposed approach yields a close connection between modelling and nonlinear dynamics. We illustrate the investigation of generalized models by considering examples from three different disciplines of science: a socio-economic model of dynastic cycles in china, a model for a coupled laser system and a general ecological food web.

  17. Journal of Biomechanics 41 (2008) 10691076 A dynamic model of jaw and hyoid biomechanics during chewing

    E-Print Network [OSTI]

    British Columbia, University of

    2008-01-01

    Journal of Biomechanics 41 (2008) 1069­1076 A dynamic model of jaw and hyoid biomechanics during Our understanding of human jaw biomechanics has been enhanced by computational modelling et al., 2002; Curtis et al., 1997; Hamdy et al., 2000; Bakke et al., 2007). Its biomechanics however

  18. Molecular Dynamics modelling of the adhesive interaction between fine F. A. Gilabert

    E-Print Network [OSTI]

    Krivtsov, Anton M.

    Molecular Dynamics modelling of the adhesive interaction between fine particles F. A. Gilabert the frictionless adhesive interaction force between two fine cohesive polymer grains. The model consists of three a higher resolution near the contact area. Secondly, the cohesion strength (i.e., the work of adhesion

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

    E-Print Network [OSTI]

    A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations Characterizing and optimizing overall performance of wind plants composed of large numbers at the National Renewable Energy Laboratory (NREL) are coupling physical models of the atmosphere and wind

  20. El Nino duration time (month) Dynamic coupling of an ENSO model to the

    E-Print Network [OSTI]

    Goelzer, Heiko

    El Nino duration time (month) Dynamic coupling of an ENSO model to the global coupled climate model changes in the thermohaline circulation and changes in the El Nino/Southern Oscillation (ENSO), the Zebiak distribution El Nino event interval (month) · Interval between ENSO events shifted towards longer times