Regional Dynamics Model (REDYN) | Open Energy Information
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Tools for dynamic model development
Schaber, Spencer Daniel
2014-01-01T23:59:59.000Z
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 ...
Mesoscale ocean dynamics modeling
mHolm, D.; Alber, M.; Bayly, B.; Camassa, R.; Choi, W.; Cockburn, B.; Jones, D.; Lifschitz, A.; Margolin, L.; Marsden, L.; Nadiga, B.; Poje, A.; Smolarkiewicz, P. [Los Alamos National Lab., NM (United States); Levermore, D. [Arizona Univ., Tucson, AZ (United States)
1996-05-01T23:59:59.000Z
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The ocean is a very complex nonlinear system that exhibits turbulence on essentially all scales, multiple equilibria, and significant intrinsic variability. Modeling the ocean`s dynamics at mesoscales is of fundamental importance for long-time-scale climate predictions. A major goal of this project has been to coordinate, strengthen, and focus the efforts of applied mathematicians, computer scientists, computational physicists and engineers (at LANL and a consortium of Universities) in a joint effort addressing the issues in mesoscale ocean dynamics. The project combines expertise in the core competencies of high performance computing and theory of complex systems in a new way that has great potential for improving ocean models now running on the Connection Machines CM-200 and CM-5 and on the Cray T3D.
DYNAMIC MODELING FUEL PROCESSORS
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
Modeling Blog Dynamics Michaela Gotz
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
Bayesian inference of stochastic dynamical models
Lu, Peter Guang Yi
2013-01-01T23:59:59.000Z
A new methodology for Bayesian inference of stochastic dynamical models is developed. The methodology leverages the dynamically orthogonal (DO) evolution equations for reduced-dimension uncertainty evolution and the Gaussian ...
Dynamical modeling of tidal streams
Bovy, Jo, E-mail: bovy@ias.edu [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2014-11-01T23:59:59.000Z
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.
Modelling and Dynamic Simulation for Process Control
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
Quantitative Modeling of High Temperature Magnetization Dynamics
Zhang, Shufeng
2009-03-01T23:59:59.000Z
Final Technical Report Project title: Quantitative Modeling of High Temperature Magnetization Dynamics DOE/Office of Science Program Manager Contact: Dr. James Davenport
Conceptual aircraft dynamics from inverse aircraft modeling
Ziegler, Gregory E
1999-01-01T23:59:59.000Z
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...
Dynamic competition model for construction contractors
Kim, Hyung Jin
2004-01-01T23:59:59.000Z
competition, a system dynamics model has been developed based on the identified concepts. In this model, there are three managerial areas in which a contractor makes policy: 1) markup; 2) marketing; and 3) capacity. Each firm's backlog level is considered...
Conceptual aircraft dynamics from inverse aircraft modeling
Ziegler, Gregory E
1999-01-01T23:59:59.000Z
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...
Benchmarking of Planning Models Using Recorded Dynamics
Huang, Zhenyu; Yang, Bo; Kosterev, Dmitry
2009-03-15T23:59:59.000Z
Power system planning extensively uses model simulation to understand the dynamic behaviors and determine the operating limits of a power system. Model quality is key to the safety and reliability of electricity delivery. Planning model benchmarking, or model validation, has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent dynamic behavior of power system components, it has been essential to validate models against actual measurements. The development of phasor technology provides such measurements and represents a new opportunity for model validation as phasor measurements can capture power system dynamics with high-speed, time-synchronized data. Previously, methods for rigorous comparison of model simulation and recorded dynamics have been developed and applied to quantify model quality of power plants in the Western Electricity Coordinating Council (WECC). These methods can locate model components which need improvement. Recent work continues this effort and focuses on how model parameters may be calibrated to match recorded dynamics after the problematic model components are identified. A calibration method using Extended Kalman Filter technique is being developed. This paper provides an overview of prior work on model validation and presents new development on the calibration method and initial results of model parameter calibration.
OPTIMAL CONTROL WITH ADAPTIVE INTERNAL DYNAMICS MODELS
Vijayakumar, Sethu
. The optimal feedback control law for systems with non-linear dynamics and non-quadratic costs can be foundOPTIMAL CONTROL WITH ADAPTIVE INTERNAL DYNAMICS MODELS Djordje Mitrovic, Stefan Klanke, and Sethu, optimal control, adaptive control, robot simulation Abstract: Optimal feedback control has been proposed
Simple Dynamic Gasifier Model That Runs in Aspen Dynamics
Robinson, P.J.; Luyben, W.L. [Lehigh University, Bethlehem, PA (United States). Dept. of Chemical Engineering
2008-10-15T23:59:59.000Z
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.
Dynamic modeling issues for power system applications
Song, Xuefeng
2005-02-17T23:59:59.000Z
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...
Modeling of Alpine Atmospheric Dynamics II
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
Bilayer Structure and Lipid Dynamics in a Model Stratum Corneum...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Bilayer Structure and Lipid Dynamics in a Model Stratum Corneum with Oleic Acid. Bilayer Structure and Lipid Dynamics in a Model Stratum Corneum with Oleic Acid. Abstract: The...
Protein viscoelastic dynamics: a model system
Craig Fogle; Joseph Rudnick; David Jasnow
2015-02-02T23:59:59.000Z
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.
Dynamical models with a general anisotropy profile
M. Baes; E. Van Hese
2007-05-28T23:59:59.000Z
Both numerical simulations and observational evidence indicate that the outer regions of galaxies and dark matter haloes are typically mildly to significantly radially anisotropic. The inner regions can be significantly non-isotropic, depending on the dynamical formation and evolution processes. In an attempt to break the lack of simple dynamical models that can reproduce this behaviour, we explore a technique to construct dynamical models with an arbitrary density and an arbitrary anisotropy profile. We outline a general construction method and propose a more practical approach based on a parameterized anisotropy profile. This approach consists of fitting the density of the model with a set of dynamical components, each of which have the same anisotropy profile. Using this approach we avoid the delicate fine-tuning difficulties other fitting techniques typically encounter when constructing radially anisotropic models. We present a model anisotropy profile that generalizes the Osipkov-Merritt profile, and that can represent any smooth monotonic anisotropy profile. Based on this model anisotropy profile, we construct a very general seven-parameter set of dynamical components for which the most important dynamical properties can be calculated analytically. We use the results to look for simple one-component dynamical models that generate simple potential-density pairs while still supporting a flexible anisotropy profile. We present families of Plummer and Hernquist models in which the anisotropy at small and large radii can be chosen as free parameters. We also generalize these two families to a three-parameter family that self-consistently generates the set of Veltmann potential-density pairs. (Abridged...)
Consistent nonlinear dynamics: identifying model inadequacy
Patrick E. McSharry; Leonard A. Smith
2004-03-09T23:59:59.000Z
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.
Dynamic models for nonstationary signal segmentation
Penny, Will
widely used in the biomedical signal processing com munity there are relatively few applications usingDynamic models for nonstationary signal segmentation William D. Penny and Stephen J. Roberts wknown parametric technique for the spectral esti mation of stationary signals [1]. The standard AR model can also
STOCHASTIC DYNAMICS OF A COUPLED ATMOSPHEREOCEAN MODEL
by an energy balance model. The oceanic dynamics is de- scribed by the Navier-Stokes equation in vorticity form and the transport equations for heat and salinity. The energy balance model is under random impact due to's longwave radiation coefficient and the shortwave solar radiation profile. Third, we have demon- strated
Dynamic Modeling of Butterfly Subdivision Surfaces
Qin, Hong
on control vertices. This provides the user an intuitive and natural feeling that is produced while modeling manipulation of control points, whereas we provide interaction tools that directly manipulate the smooth limitDynamic Modeling of Butterfly Subdivision Surfaces Chhandomay Mandal, Hong Qin, Member, IEEE
Six Degree of Freedom Morphing Aircraft Dynamical Model with Aerodynamics
Niksch, Adam
2010-01-14T23:59:59.000Z
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...
Modeling the Dynamics of Compromised Networks
Soper, B; Merl, D M
2011-09-12T23:59:59.000Z
Accurate predictive models of compromised networks would contribute greatly to improving the effectiveness and efficiency of the detection and control of network attacks. Compartmental epidemiological models have been applied to modeling attack vectors such as viruses and worms. We extend the application of these models to capture a wider class of dynamics applicable to cyber security. By making basic assumptions regarding network topology we use multi-group epidemiological models and reaction rate kinetics to model the stochastic evolution of a compromised network. The Gillespie Algorithm is used to run simulations under a worst case scenario in which the intruder follows the basic connection rates of network traffic as a method of obfuscation.
Dynamical dark matter. II. An explicit model
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Dienes, Keith R.; Thomas, Brooks
2012-04-01T23:59:59.000Z
In a recent paper [K. R. Dienes and B. Thomas, Phys. Rev. D 85, 083523 (2012).], we introduced “dynamical dark matter,” a new framework for dark-matter physics, and outlined its underlying theoretical principles and phenomenological possibilities. Unlike most traditional approaches to the dark-matter problem which hypothesize the existence of one or more stable dark-matter particles, our dynamical dark-matter framework is characterized by the fact that the requirement of stability is replaced by a delicate balancing between cosmological abundances and lifetimes across a vast ensemble of individual dark-matter components. This setup therefore collectively produces a time-varying cosmological dark-matter abundance, and the different dark-matter components can interact and decay throughout the current epoch. While the goal of our previous paper was to introduce the broad theoretical aspects of this framework, the purpose of the current paper is to provide an explicit model of dynamical dark matter and demonstrate that this model satisfies all collider, astrophysical, and cosmological constraints. The results of this paper therefore constitute an “existence proof” of the phenomenological viability of our overall dynamical dark-matter framework, and demonstrate that dynamical dark matter is indeed a viable alternative to the traditional paradigm of dark-matter physics. Dynamical dark matter must therefore be considered alongside other approaches to the dark-matter problem, particularly in scenarios involving large extra dimensions or string theory in which there exist large numbers of particles which are neutral under standard-model symmetries.
Analytical modeling of balloon launch dynamics
Strganac, Thomas W
1980-01-01T23:59:59.000Z
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...
Modeling of Reactor Kinetics and Dynamics
Matthew Johnson; Scott Lucas; Pavel Tsvetkov
2010-09-01T23:59:59.000Z
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.
DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL
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
Feature extraction for structural dynamics model validation
Hemez, Francois [Los Alamos National Laboratory; Farrar, Charles [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Nishio, Mayuko [UNIV OF TOKYO; Worden, Keith [UNIV OF SHEFFIELD; Takeda, Nobuo [UNIV OF TOKYO
2010-11-08T23:59:59.000Z
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.
Transactions in GIS Dynamic Modelling and Visualization on the Internet
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
A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,
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
The dynamic radiation environment assimilation model (DREAM)
Reeves, Geoffrey D [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Tokar, Robert L [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory; Friedel, Reiner H [Los Alamos National Laboratory
2010-01-01T23:59:59.000Z
The Dynamic Radiation Environment Assimilation Model (DREAM) is a 3-year effort sponsored by the US Department of Energy to provide global, retrospective, or real-time specification of the natural and potential nuclear radiation environments. The DREAM model uses Kalman filtering techniques that combine the strengths of new physical models of the radiation belts with electron observations from long-term satellite systems such as GPS and geosynchronous systems. DREAM includes a physics model for the production and long-term evolution of artificial radiation belts from high altitude nuclear explosions. DREAM has been validated against satellites in arbitrary orbits and consistently produces more accurate results than existing models. Tools for user-specific applications and graphical displays are in beta testing and a real-time version of DREAM has been in continuous operation since November 2009.
Analytical modeling of balloon launch dynamics
Strganac, Thomas W
1980-01-01T23:59:59.000Z
Subject; Aerospace Engineer1ng ANALYTICAL MODELING OF BALLOON LAUNCH DYNAMICS A Thesis by THOMAS WILLIAM STRGANAC Approved as to sty1e and content by: (Chairman of Committee) (Member) (Member) (Head of Dep rtment) December 1980 ABSTRACT Analyt1... 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...
Direct modelling of envelope dynamics in resonant inverters
is to model the AC dynamics from input modulation to output envelops to facilitate optimised controller designDirect modelling of envelope dynamics in resonant inverters Y. Yin, R. Zane, R. Erickson and J. Glaser A direct dynamic modelling approach is proposed for envelope signals in resonant inverters
Restoration of the Potosi Dynamic Model 2010
Adushita, Yasmin; Leetaru, Hannes
2014-09-30T23:59:59.000Z
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.
A Game-Theoretical Dynamic Model for Electricity Markets
Aswin Kannan
2010-10-06T23:59:59.000Z
Oct 6, 2010 ... Abstract: We present a game-theoretical dynamic model for competitive electricity markets.We demonstrate that the model can be used to ...
A Game-Theoretical Dynamic Model for Electricity Markets
Oct 6, 2010 ... Abstract: We present a game-theoretical dynamic model for competitive electricity markets.We demonstrate that the model can be used to ...
AFDM: An Advanced Fluid-Dynamics Model
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,
1990-09-01T23:59:59.000Z
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.
Dislocation dynamics: from microscopic models to macroscopic crystal plasticity
Hajj, A El; Monneau, R
2009-01-01T23:59:59.000Z
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.
Gradient Navigation Model for Pedestrian Dynamics
Felix Dietrich; Gerta Köster
2014-05-14T23:59:59.000Z
We present a new microscopic ODE-based model for pedestrian dynamics: the Gradient Navigation Model. The model uses a superposition of gradients of distance functions to directly change the direction of the velocity vector. The velocity is then integrated to obtain the location. The approach differs fundamentally from force based models needing only three equations to derive the ODE system, as opposed to four in, e.g., the Social Force Model. Also, as a result, pedestrians are no longer subject to inertia. Several other advantages ensue: Model induced oscillations are avoided completely since no actual forces are present. The derivatives in the equations of motion are smooth and therefore allow the use of fast and accurate high order numerical integrators. At the same time, existence and uniqueness of the solution to the ODE system follow almost directly from the smoothness properties. In addition, we introduce a method to calibrate parameters by theoretical arguments based on empirically validated assumptions rather than by numerical tests. These parameters, combined with the accurate integration, yield simulation results with no collisions of pedestrians. Several empirically observed system phenomena emerge without the need to recalibrate the parameter set for each scenario: obstacle avoidance, lane formation, stop-and-go waves and congestion at bottlenecks. The density evolution in the latter is shown to be quantitatively close to controlled experiments. Likewise, we observe a dependence of the crowd velocity on the local density that compares well with benchmark fundamental diagrams.
Nonlinear Hybrid Dynamical Systems: Modeling, Optimal Control, and Applications
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
Modelling and simulation of multidisciplinary dynamic systems Lead: A. Fakri.
Baudoin, GeneviÃ¨ve
Modelling and simulation of multidisciplinary dynamic systems Lead: A. Fakri. Permanent members: P. Integration of various engineering disciplines and the consideration of the dynamic control need a concurrent suited for the energy exchanges to study multidisciplinary dynamic engineering systems modelling. Our
Dynamics of an Economics Model for Generation Coupled to the OPA Power Transmission Model
Dobson, Ian
Dynamics of an Economics Model for Generation Coupled to the OPA Power Transmission Model B. A a dynamic model of the power transmission system (OPA) and a simple economic model of power generation development. Despite the simplicity of this economic model, complex dynamics both in the economics (prices
Linking Dynamical and Population Genetic Models of Persistent Viral Infection
Kelly, John K.; Williamson, Scott; Orive, Maria E.; Smith, Marilyn S.; Holt, Robert D.
2003-07-01T23:59:59.000Z
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 ...
AFDM: An Advanced Fluid-Dynamics Model
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))
1990-09-01T23:59:59.000Z
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.
Solid Oxide Fuel Cell: Perspective of Dynamic Modeling and Control
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
Dynamic Bayesian Networks model to estimate process availability.
Paris-Sud XI, Université de
Dynamic Bayesian Networks model to estimate process availability. Weber P. Centre de Recherche en reported here explores a new methodology to develop Dynamic Bayesian Network-based Availability of the system availability estimation comparing DBN model with the classical Markov chain model. Keywords
LDRD final report : mesoscale modeling of dynamic loading of...
Office of Scientific and Technical Information (OSTI)
Technical Report: LDRD final report : mesoscale modeling of dynamic loading of heterogeneous materials. Citation Details In-Document Search Title: LDRD final report : mesoscale...
Albert, Réka
with a random network with a given degree distribution P(k). Mark edges with probability T. DisregardThe two faces of network dynamics Evolving network models describe the dynamics (assembly, evolution) OF networks by the addition/removal of nodes and edges. It is possible to have network dynamics
Deep Learning Helicopter Dynamics Models Ali Punjani and Pieter Abbeel
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
From quantum to classical dynamics: Dynamic crossover in the relativistic $O(N)$ model
Mesterházy, David; Tanizaki, Yuya
2015-01-01T23:59:59.000Z
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.
Factoring Gaussian Precision Matrices for Linear Dynamic Models
Frankel, Joe; King, Simon
2007-01-01T23:59:59.000Z
The linear dynamic model (LDM), also known as the Kalman filter model, has been the subject of research in the engineering, control, and more recently, machine learning and speech technology communities. The Gaussian noise processes are usually...
A Dynamic Network Oligopoly Model Transportation Costs, Product Differentiation,
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
A Dynamic Model of Social Network Formation Brian Skyrms 1
Pemantle, Robin
A Dynamic Model of Social Network Formation Brian Skyrms 1 Robin Pemantle 2;3 ABSTRACT: We consider a dynamic social network model in which agents play repeated games in pairings determined by a stochastically evolving social network. In- dividual agents begin to interact at random, with the interactions
Computational Modeling of Brain Dynamics during Repetitive Head Motions
Burtscher, Martin
Computational Modeling of Brain Dynamics during Repetitive Head Motions Igor Szczyrba School the HIC scale to arbitrary head motions. Our simulations of the brain dynamics in sagittal and horizontal injury modeling, resonance effects 1 Introduction A rapid head motion can result in a severe brain injury
A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling
Paris-Sud XI, Université de
A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling and Control L. Nehaoua and dynamics modeling will be presented. Some results are shown, validating the actutation requirements and platform control. 1. INTRODUCTION Road safety has become a major political and economical issue. While all
Learning vehicular dynamics, with application to modeling helicopters
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
Learning vehicular dynamics, with application to modeling helicopters
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
A model simulation of white-winged dove population dynamics in the Tamaulipan Biotic Province
Martinez, Cristina Ann
2002-01-01T23:59:59.000Z
the population dynamics model. The current population dynamics model is useful in the understanding of observed patterns and processes of WWDO population dynamics. The model also serves to direct research efforts that would enhance the reliability of the model...
Dynamic Modeling of Cascading Failure in Power Systems
Song, Jiajia; Ghanavati, Goodarz; Hines, Paul D H
2014-01-01T23:59:59.000Z
The modeling of cascading failure in power systems is difficult because of the many different mechanisms involved; no single model captures all of these mechanisms. Understanding the relative importance of these different mechanisms is an important step in choosing which mechanisms need to be modeled for particular types of cascading failure analysis. This work presents a dynamic simulation model of both power networks and protection systems, which can simulate a wider variety of cascading outage mechanisms, relative to existing quasi-steady state (QSS) models. The model allows one to test the impact of different load models and protections on cascading outage sizes. This paper describes each module of the developed dynamic model and demonstrates how different mechanisms interact. In order to test the model we simulated a batch of randomly selected $N-2$ contingencies for several different static load configurations, and found that the distribution of blackout sizes and event lengths from the proposed dynamic...
Dynamic Modeling in Solid-Oxide Fuel Cells Controller Design
Lu, Ning; Li, Qinghe; Sun, Xin; Khaleel, Mohammad A.
2007-06-28T23:59:59.000Z
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.
Generic solar photovoltaic system dynamic simulation model specification.
Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas
2013-10-01T23:59:59.000Z
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.
Optimal control with adaptive internal dynamics models
Mitrovic, Djordje; Klanke, Stefan; Vijayakumar, Sethu
2008-01-01T23:59:59.000Z
Optimal feedback control has been proposed as an attractive movement generation strategy in goal reaching tasks for anthropomorphic manipulator systems. The optimal feedback control law for systems with non-linear dynamics ...
Fibre Based Modeling of Wood Dynamics and Fracture
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
Dynamic Simulation Model of a Consumer Foods Production Process !
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
Dynamic Modelling for Control of Fuel Cells Federico Zenith
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
UNEDITED PREPRINT Building a dynamic growth model for trembling
García, Oscar
UNEDITED PREPRINT Building a dynamic growth model for trembling aspen in Western Canada without age for even-aged thinned or unthinned stands dominated by trembling aspen. Estimation used permanent sample words: Forest growth and yield, Populus tremuloides, quacking aspen, thinning, dynamical systems, TAG. 1
Transmission Dynamics of an Influenza Model with Age of Infection ...
2010-07-20T23:59:59.000Z
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 ...
Model reduction for nonlinear dynamical systems with parametric uncertainties
Zhou, Yuxiang Beckett
2012-01-01T23:59:59.000Z
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 ...
2.003 Modeling Dynamics and Control I, Spring 2002
Trumper, David L.
First of two-term sequence on modeling, analysis and control of dynamic systems. Mechanical translation, uniaxial rotation, electrical circuits and their coupling via levers, gears and electro-mechanical devices. Analytical ...
Off-line calibration of Dynamic Traffic Assignment models
Balakrishna, Ramachandran, 1978-
2006-01-01T23:59:59.000Z
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 ...
Applications of axial and radial compressor dynamic system modeling
Spakovszky, Zoltán S. (Zoltán Sándor), 1972-
2001-01-01T23:59:59.000Z
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. ...
A Dynamic Island Model for Adaptive Operator Selection Caner Candan
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
Modeling and control of undesirable dynamics in atomic force microscopes
El Rifai, Osamah M
2002-01-01T23:59:59.000Z
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 ...
Human Growth and Body Weight Dynamics: An Integrative Systems Model
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 ...
Dynamic Modelling and Control Design of Pre-combustion Power
Foss, Bjarne A.
- pressors, gas and steam turbines and a heat recovery system. Analysis of dynamic models at an early stage principles. The pre- combustion gas power cycle plants consist of reformers and separation units, com
SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL
ii SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL: A LOOK to society in the long run. My goal was to use a "hybrid" energy economy model (CIMS), which combines.............................................. 1 1.2 The Challenge of Energy-Economy Modelling
A Diffusion Model in Population Genetics with Mutation and Dynamic
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
COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS
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
REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump
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
Dynamic wind turbine models in power system simulation tool
Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D. Hansen, Florin Iov models in power system simulation tool DIgSILENT Department: Wind Energy Department Risø-R-1400(ed.2)(EN and at a system level. The report contains both the description of DIgSILENT built-in models for the electrical
Developing Generic Dynamic Models for the 2030 Eastern Interconnection Grid
Kou, Gefei [ORNL; Hadley, Stanton W [ORNL; Markham, Penn N [ORNL; Liu, Yilu [ORNL
2013-12-01T23:59:59.000Z
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.
Dynamic reactor modeling with applications to SPR and ZEDNA.
Suo-Anttila, Ahti Jorma
2011-12-01T23:59:59.000Z
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.
Mesoscale modeling of phase transition dynamics of thermoresponsive polymers
Li, Zhen; Li, Xuejin; Karniadakis, George Em
2015-01-01T23:59:59.000Z
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.
ERCOT's Dynamic Model of Wind Turbine Generators: Preprint
Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.
2005-08-01T23:59:59.000Z
By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.
Human Muscle Fatigue Model in Dynamic Motions
Boyer, Edmond
into account. In this paper, each human joint is assumed to be controlled by two muscle groups to generate on motor units pattern. They demonstrated the relationship among muscle activation, fatigue and recovery fatigue trend in static working posture (elbow = 90 , shoulder = 30 ), but in dynamic working situation
Dynamic competition model for construction contractors
Kim, Hyung Jin
2004-01-01T23:59:59.000Z
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...
A stochastic evolutionary model for capturing human dynamics
Fenner, Trevor; Loizou, George
2015-01-01T23:59:59.000Z
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.
A Dynamic Model with Import Quota Constraints
Basak, Suleyman
2004-07-09T23:59:59.000Z
The analysis of import quotas is predominantly based on a static model, which is unable to capture the fact that a quota is imposed over a period of time. This article develops a continuous-time model ...
Modeling emotion dynamics in intelligent agents
Seif El-Nasr, Magy
1998-01-01T23:59:59.000Z
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...
Structure formation: Models, Dynamics and Status
T. Padmanabhan
1995-08-25T23:59:59.000Z
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.
Numerically Estimating Internal Models of Dynamic Virtual Objects
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
Numerical Modeling of Brain Dynamics in Traumatic Situations -Impulsive Translations
Burtscher, Martin
.S.A. Abstract We numerically model the brain dy- namics during and after impulsive head translations using brain injuries appear among boxers and shaken babies despite minimal rotations of their heads. Modeling head translations also helps understand the brain dynamics during head rotations about an arbitrary
A STOCHASTIC CELLULAR AUTOMATON MODEL OF EBOLA VIRUS DYNAMICS
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
Thermodiffusion in model nanofluids by molecular dynamics simulations
Paris-Sud XI, Université de
1 Thermodiffusion in model nanofluids by molecular dynamics simulations G. Galliero1,2,* , S. Volz3-Jones fluids and for model nanofluids (spherical non-metallic nanoparticles + Lennard-Jones fluid) where concentration. Then, in nanofluids in the liquid state, by changing the nature of the nanoparticle (size, mass
Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS
Shapiro, Benjamin
ABSTRACT Title of dissertation: MODELING, SIMULATING, AND CONTROLLING THE FLUID DYNAMICS OF ELECTRO an algorithm to steer indi- vidual particles inside the EWOD system by control of actuators already present number of actuators available in the EWOD system. #12;MODELING, SIMULATING, AND CONTROLLING THE FLUID
A Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae
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
DYNAMIC MODELLING OF AUTONOMOUS POWER SYSTEMS INCLUDING RENEWABLE POWER SOURCES.
Paris-Sud XI, Université de
DYNAMIC MODELLING OF AUTONOMOUS POWER SYSTEMS INCLUDING RENEWABLE POWER SOURCES. ABSTRACT The use of renewable energies for electricity production presents a growing interest, especially in autonomous power production imposes several difficulties to the power system operation when penetration is high. Here, a model
Fluid Dynamic Models of Flagellar and Ciliary Beating
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
Dislocation dynamics: from microscopic models to macroscopic crystal plasticity
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
Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire
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
Controlling Social Dynamics with a Parametrized Model of Floor Regulation
Das, Suman
Controlling Social Dynamics with a Parametrized Model of Floor Regulation Crystal Chao, Andrea L is to build autonomous robot controllers for successfully engaging in human-like turn-taking interactions. Towards this end, we present CADENCE, a novel computational model and architecture that explicitly reasons
Model Reduction Near Periodic Orbits of Hybrid Dynamical Systems
Sastry, S. Shankar
manipulation in manufacturing [2], gene regulation in cells [3], and power generation in electrical systems [41 Model Reduction Near Periodic Orbits of Hybrid Dynamical Systems Samuel A. Burden, Shai Revzen system. We demonstrate reduction of a highÂdimensional underactuated mechanical model for terrestrial
Dynamical many-body localization in an integrable model
Aydin Cem Keser; Sriram Ganeshan; Gil Refael; Victor Galitski
2015-06-17T23:59:59.000Z
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.
Modeling and simulation of consumer response to dynamic pricing.
Valenzuela, J.; Thimmapuram, P.; Kim, J (Decision and Information Sciences); (Auburn Univ.)
2012-08-01T23:59:59.000Z
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.
Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model Output
Shi, Tao
Modeling Space-Time Dynamics of Aerosols Using Satellite Data and Atmospheric Transport Model of aerosol optical depth across mainland Southeast Asia. We include a cross validation study to assess
Friction in a Model of Hamiltonian Dynamics
Juerg Froehlich; Zhou Gang; Avy Soffer
2011-11-01T23:59:59.000Z
We study the motion of a heavy tracer particle weakly coupled to a dense ideal Bose gas exhibiting Bose-Einstein condensation. In the so-called mean-field limit, the dynamics of this system approaches one determined by nonlinear Hamiltonian evolution equations describing a process of emission of Cerenkov radiation of sound waves into the Bose-Einstein condensate along the particle's trajectory. The emission of Cerenkov radiation results in a friction force with memory acting on the tracer particle and causing it to decelerate until it comes to rest.
DYNAMICAL MODEL OF AN EXPANDING SHELL
Pe'er, Asaf [Harvard-Smithsonian Center for Astrophysics, MS-51, 60 Garden Street, Cambridge, MA 02138 (United States)
2012-06-10T23:59:59.000Z
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.
Weeks, Eric R.
this behavior. The mode coupling theory [1] describes many aspects of dynamical behavior at high T- stood as a simple activated bondbreaking process. Here, we perform molecular dynamics (MD) simula- tionsSpatially Heterogeneous Dynamics and Dynamic Facilitation in a Model of Viscous Silica Michael
Slow dynamics in a model of the cellulose network
O. V. Manyuhina; A. Fasolino; M. I. Katsnelson
2007-06-07T23:59:59.000Z
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.
Generative modeling of dynamic visual scenes
Lin, Dahua, Ph. D. Massachusetts Institute of Technology
2012-01-01T23:59:59.000Z
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 ...
Modeling Infection with Multi-agent Dynamics
Dong, Wen
2012-01-01T23:59:59.000Z
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 ...
Modeling emotion dynamics in intelligent agents
Seif El-Nasr, Magy
1998-01-01T23:59:59.000Z
OF SIMULATION AND RESULTS . . . . . . . . . . . D. CONTRIBUTIONS 7. STRUCTURE OF THE THESIS 1 3 4 7 9 13 13 15 18 18 19 11 PREVIOUS WORK . . 20 1. PSYCHOLOGICAL MODELS . A. MOTIVATIONAL STATES . B. APPRAISAL MODELS OF EMOTIONS... all the needs and urges, while the mind is the heart of the rational thinking process [9]. After three centuries, new theories of emotions were established. By 1884, William James [15] published his article "What is Emotion?" At that time...
Analytical properties of a three-compartmental dynamical demographic model
E. B. Postnikov
2015-07-29T23:59:59.000Z
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.
CSAW: a dynamical model of protein folding
Kerson Huang
2006-01-12T23:59:59.000Z
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.
Model Based Safety Assessment Dynamic System
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
Green Algae as Model Organisms for Biological Fluid Dynamics
Goldstein, Raymond E
2014-01-01T23:59:59.000Z
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...
Green Algae as Model Organisms for Biological Fluid Dynamics
Raymond E. Goldstein
2014-09-08T23:59:59.000Z
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.
Dynamic Modeling and Cascaded Control for a Multi-Evaporator Supermarket Refrigeration System
Gupta, Ankush 1986-
2012-09-27T23:59:59.000Z
dynamic models for the HVAC components, which leads to implementation of better control and optimization techniques. In this research, efforts are made to model a multi-evaporator system. A novel dynamic modeling technique is proposed based on moving...
Dynamic crack initiation toughness : experiments and peridynamic modeling.
Foster, John T.
2009-10-01T23:59:59.000Z
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.
A Dynamical Model of Plasma Turbulence in the Solar Wind
Howes, G G
2015-01-01T23:59:59.000Z
A dynamical approach, rather than the usual statistical approach, is taken to explore the physical mechanisms underlying the nonlinear transfer of energy, the damping of the turbulent fluctuations, and the development of coherent structures in kinetic plasma turbulence. It is argued that the linear and nonlinear dynamics of Alfven waves are responsible, at a very fundamental level, for some of the key qualitative features of plasma turbulence that distinguish it from hydrodynamic turbulence, including the anisotropic cascade of energy and the development of current sheets at small scales. The first dynamical model of kinetic turbulence in the weakly collisional solar wind plasma that combines self-consistently the physics of Alfven waves with the development of small-scale current sheets is presented and its physical implications are discussed. This model leads to a simplified perspective on the nature of turbulence in a weakly collisional plasma: the nonlinear interactions responsible for the turbulent casca...
Model Independent Analysis of Beam Centroid Dynamics in Accelerators
Wang, Chun-xi
2003-04-21T23:59:59.000Z
Fundamental issues in Beam-Position-Monitor (BPM)-based beam dynamics observations are studied in this dissertation. The major topic is the Model-Independent Analysis (MIA) of beam centroid dynamics. Conventional beam dynamics analysis requires a certain machine model, which itself of ten needs to be refined by beam measurements. Instead of using any particular machine model, MIA relies on a statistical analysis of the vast amount of BPM data that often can be collected non-invasively during normal machine operation. There are two major parts in MIA. One is noise reduction and degrees-of-freedom analysis using a singular value decomposition of a BPM-data matrix, which constitutes a principal component analysis of BPM data. The other is a physical base decomposition of the BPM-data matrix based on the time structure of pulse-by-pulse beam and/or machine parameters. The combination of these two methods allows one to break the resolution limit set by individual BPMs and observe beam dynamics at more accurate levels. A physical base decomposition is particularly useful for understanding various beam dynamics issues. MIA improves observation and analysis of beam dynamics and thus leads to better understanding and control of beams in both linacs and rings. The statistical nature of MIA makes it potentially useful in other fields. Another important topic discussed in this dissertation is the measurement of a nonlinear Poincare section (one-turn) map in circular accelerators. The beam dynamics in a ring is intrinsically nonlinear. In fact, nonlinearities are a major factor that limits stability and influences the dynamics of halos. The Poincare section map plays a basic role in characterizing and analyzing such a periodic nonlinear system. Although many kinds of nonlinear beam dynamics experiments have been conducted, no direct measurement of a nonlinear map has been reported for a ring in normal operation mode. This dissertation analyzes various issues concerning map measurements and shows that it is possible to measure the Poincare section map (in terms of Taylor series) of a circular accelerator to a surprisingly high order and accuracy based on present BPM technology. MIA can overcome the inherent limit of BPM resolution. Nonlinear map measurements will advance understanding of the beam dynamics of a ring.
Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction
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
Parameterized Model Order Reduction of Nonlinear Dynamical Systems
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
Transport coefficients of a mesoscopic fluid dynamics model
N. Kikuchi; C. M. Pooley; J. F. Ryder; J. M. Yeomans
2003-02-21T23:59:59.000Z
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.
Lessons Learned from Quantitative Dynamical Modeling in Systems Biology
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
Non-perturbative Dynamical Decoupling Control: A Spin Chain Model
Zhao-Ming Wang; Lian-Ao Wu; Jun Jing; Bin Shao; Ting Yu
2012-03-24T23:59:59.000Z
This paper considers a spin chain model by numerically solving the exact model to explore the non-perturbative dynamical decoupling regime, where an important issue arises recently (J. Jing, L.-A. Wu, J. Q. You and T. Yu, arXiv:1202.5056.). Our study has revealed a few universal features of non-perturbative dynamical control irrespective of the types of environments and system-environment couplings. We have shown that, for the spin chain model, there is a threshold and a large pulse parameter region where the effective dynamical control can be implemented, in contrast to the perturbative decoupling schemes where the permissible parameters are represented by a point or converge to a very small subset in the large parameter region admitted by our non-perturbative approach. An important implication of the non-perturbative approach is its flexibility in implementing the dynamical control scheme in a experimental setup. Our findings have exhibited several interesting features of the non-perturbative regimes such as the chain-size independence, pulse strength upper-bound, noncontinuous valid parameter regions, etc. Furthermore, we find that our non-perturbative scheme is robust against randomness in model fabrication and time-dependent random noise.
Dynamic and Static Influence Models on Starbucks Networks Minkyoung Kim
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
Wind Energy Applications of Unified and Dynamic Turbulence Models
Heinz, Stefan
Wind Energy Applications of Unified and Dynamic Turbulence Models Stefan Heinz and Harish Gopalan applicable as a low cost alternative. 1 Introduction There is a growing interest in using wind energy suggests the possibility of providing 20% of the electricity in the U.S. by wind energy in 2030
Modelling Dynamic Trust with Property Based Attestation in Trusted Platforms
Paris-Sud XI, Université de
Modelling Dynamic Trust with Property Based Attestation in Trusted Platforms Aarthi Nagarajan attestation in trusted computing provides the ability to reason about the state of a platform using integrity attestation by abstracting low level binary values to high level security properties or functions of platforms
Modeling Combined Time-and Event-Driven Dynamic Systems
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
Geographical Information Systems and Dynamic Modeling via Agent Based Systems
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
Multiscale modeling of polystyrene dynamics in different environments
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
Approximate Dynamic Programming for Networks: Fluid Models and Constraint Reduction
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
Model-Driven Dynamic Control of Embedded Wireless Sensor Networks
Agarwal, Pankaj K.
Model-Driven Dynamic Control of Embedded Wireless Sensor Networks Paul G. Flikkema1 , Pankaj K-generation wireless sensor networks may revolution- ize understanding of environmental change by assimilating heteroge of wireless sensor networks is now becoming a mature research field. As a result, the discipline is undergoing
Dynamical Analysis of the Fitzhugh-Nagumo Model
Beer, Randall D.
Dynamical Analysis of the Fitzhugh-Nagumo Model #12;IU/COGS-Q580/Beer This isYour Brain #12;IU/COGS-Q580/Beer Action Potentials Tateno, T., Harsch, A. and Robinson, H.P.C. (2004). Threshold Firing. Neurophysiology 92:2283-2294. #12;IU/COGS-Q580/Beer The Ionic Basis of the Action Potential Delcomyn, F. (1998
LECTURES ON GLAUBER DYNAMICS FOR DISCRETE SPIN MODELS
Transitions 5.1 The SolidonSolid Approximation 5.2 Back to the Ising Model 5.3 Recent Progresses 6. Phase Measures 2.3 Weak and Strong Mixing Conditions 2.4 Mixing properties and bounds on relative densities 3 on the Spectral Gap with Free B.C 6.6 Mixed B.C 6.7 Applications 7. Glauber Dynamics for the Dilute Ising Model 7
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gasenzer, Thomas [Universitat Heidelberg, Institut fur Theoretische Physik, Heidelberg (Germany); GSI, ExtreMe Matter Institute EMMI, Darmstadt (Germany); McLerran, Larry [Brookhaven National Laboratory, Physics Department, RIKEN BNL Research Center Upton NY (United States); China Central Normal University, Physics Department, Wuhan (China); Pawlowski, Jan M [Universitat Heidelberg, Institut fur Theoretische Physik, Heidelberg (Germany); GSI, ExtreMe Matter Institute EMMI, Darmstadt (Germany); Sexty, Denes [Universitat Heidelberg, Institut fur Theoretische Physik, Heidelberg (Germany); GSI, ExtreMe Matter Institute EMMI, Darmstadt (Germany)
2014-10-01T23:59:59.000Z
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.
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
2014-10-01T23:59:59.000Z
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
Russell, Lynn
Geophysical Fluid Dynamics Laboratory general circulation model investigation of the indirect Corporation for Atmospheric Research, Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA V. Ramaswamy, Paul A. Ginoux, and Larry W. Horowitz Geophysical Fluid Dynamics Laboratory, Princeton, New
California at Irvine, University of
CVSys: A Coordination Framework for Dynamic and Fully Distributed Cardiovascular Modeling and dynamic simulation control. This coordination framework uniquely incorporates attributes of open indigenous and a more integrated system representation. Dynamic simulation control serves to interject new
A dynamical symmetry breaking model in Weyl space
A. Feoli; W. R. Wood; G. Papini
1998-05-11T23:59:59.000Z
The dynamical process following the breaking of Weyl geometry to Riemannian geometry is considered by studying the motion of de Sitter bubbles in a Weyl vacuum. The bubbles are given in terms of an exact, spherically symmetric thin shell solution to the Einstein equations in a Weyl-Dirac theory with a time-dependent scalar field of the form beta = f(t)/r. The dynamical solutions obtained lead to a number of possible applications. An important feature of the thin shell model is the manner in which beta provides a connection between the interior and exterior geometries since information about the exterior geometry is contained in the boundary conditions for beta.
Gaussian Process Model for Collision Dynamics of Complex Molecules
Cui, Jie
2015-01-01T23:59:59.000Z
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 ...
Sensitivity analysis of a dynamic model for submerged arc silicon furnaces.
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
Model for dynamic self-assembled magnetic surface structures.
Belkin, M.; Glatz, A.; Snezhko, A.; Aranson, I. S.; Materials Science Division; Northwestern Univ.
2010-07-07T23:59:59.000Z
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.
Modeling Dynamics in the Central Regions of Disk Galaxies
Isaac Shlosman
2004-12-07T23:59:59.000Z
The central regions of disk galaxies are hosts to supermassive black holes whose masses show a tight correlation with the properties of surrounding stellar bulges. While the exact origin of this dependency is not clear, it can be related to the very basic properties of dark matter halos and the associated gas and stellar dynamics in the central kpc of host galaxies. In this review we discuss some of the recent developments in modeling the wide spectrum of dynamical processes which can be affiliated with the above phenomena, such as the structure of molecular tori in AGN, structure formation in triaxial halos, and dissipative and non-dissipative dynamics in nested bar systems, with a particular emphasis on decoupling of gaseous nuclear bars. We also briefly touch on the subject of fueling the nuclear starbursts and AGN.
Dynamic Absorption Model for Off-Gas Separation
Veronica J. Rutledge
2011-07-01T23:59:59.000Z
Modeling and simulations will aid in the future design of U.S. advanced reprocessing plants for the recovery and recycle of actinides in used nuclear fuel. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, a rate based, dynamic absorption model is being developed in gPROMS software. Inputs include liquid and gas stream constituents, column properties, liquid and gas phase reactions, number of stages, and inlet conditions. It simulates multiple component absorption with countercurrent flow and accounts for absorption by mass transfer and chemical reaction. The assumption of each stage being a discrete well-mixed entity was made. Therefore, the model is solved stagewise. The simulation outputs component concentrations in both phases as a function of time from which the rate of absorption is determined. Temperature of both phases is output as a function of time also. The model will be used able to be used as a standalone model in addition to in series with other off-gas separation unit operations. The current model is being generated based on NOx absorption; however, a future goal is to develop a CO2 specific model. The model will have the capability to be modified for additional absorption systems. The off-gas models, both adsorption and absorption, will be made available via the server or web for evaluation by customers.
Dynamics of Matter in a Compactified Kaluza-Klein Model
Valentino Lacquaniti; Giovanni Montani
2009-02-10T23:59:59.000Z
A longstanding problem in Kaluza-Klein models is the description of matter dynamics. Within the 5D model, the dimensional reduction of the geodesic motion for a 5D free test particle formally restores electrodynamics, but the reduced 4D particle shows a charge-mass ratio that is upper bounded, such that it cannot fit to any kind of elementary particle. At the same time, from the quantum dynamics viewpoint, there is the problem of the huge massive modes generation. We present a criticism against the 5D geodesic approach and face the hypothesis that in Kaluza-Klein space the geodesic motion does not deal with the real dynamics of test particle. We propose a new approach: starting from the conservation equation for the 5D matter tensor, within the Papapetrou multipole expansion, we prove that the 5D dynamical equation differs from the 5D geodesic one. Our new equation provides right coupling terms without bounding and in such a scheme the tower of massive modes is removed.
Model of a deterministic detector and dynamical decoherence
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)
2005-07-15T23:59:59.000Z
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.
Keratin Dynamics: Modeling the Interplay between Turnover and Transport
Stephanie Portet; Anotida Madzvamuse; Andy Chung; Rudolf E. Leube; Reinhard Windoffer
2015-04-01T23:59:59.000Z
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.
Dynamic ModelingDynamic Modeling the Electric Power Networkthe Electric Power Network
Oro, Daniel
at the National Energy Modeling System/Annual Energy Outlook Conference, Washington, DC, March 10, 2003] #12
Nuclear Hybrid Energy System Modeling: RELAP5 Dynamic Coupling Capabilities
Piyush Sabharwall; Nolan Anderson; Haihua Zhao; Shannon Bragg-Sitton; George Mesina
2012-09-01T23:59:59.000Z
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.
Dynamic Versus Steady-State Modeling of FACTS Controllers in Transmission Congestion
Cañizares, Claudio A.
1 Dynamic Versus Steady-State Modeling of FACTS Controllers in Transmission Congestion Claudio A of dynamic models of power systems elements, including FACTS controllers, and a better representation controller dynamic models in market clearing and power dispatch. The research work presented here
Efficient Dynamic Modeling, Numerical Optimal Control and Experimental Results for Various Gaits
Stryk, Oskar von
Efficient Dynamic Modeling, Numerical Optimal Control and Experimental Results for Various Gaits. A fully three- dimensional dynamical model of Sony's four-legged robot is used to state an optimal control model and the algorithm for evaluating the dynamics. The formulation of the optimal control problem
Learning Multiple Models of Non-Linear Dynamics for Control under Varying Contexts
Vijayakumar, Sethu
Learning Multiple Models of Non-Linear Dynamics for Control under Varying Contexts Georgios Petkos for adaptive motor control exist which learn the system's inverse dynamics online and use this single model;II Command Context 1 Context 2 Dynamics models Context n Control Learning Commands Switch / Mix
AIAA 2001-2126 DYNAMICAL MODELS FOR CONTROL OF CAVITY OSCILLATIONS
Dabiri, John O.
AIAA 2001-2126 DYNAMICAL MODELS FOR CONTROL OF CAVITY OSCILLATIONS Clarence W. Rowley Tim Colonius have used an explicit dynamical model for control design, or analysis of performance or robustness, CA 91125 Abstract We investigate nonlinear dynamical models for self- sustained oscillations
Learning Multiple Models of Non-Linear Dynamics for Control under Varying Contexts
Toussaint, Marc
Learning Multiple Models of Non-Linear Dynamics for Control under Varying Contexts Georgios Petkos for adaptive motor control exist which learn the system's inverse dynamics online and use this single model version - to appear in ICANN 2006 #12;II Command Context 1 Context 2 Dynamics models Context n Control
Load estimation and control using learned dynamics models Georgios Petkos and Sethu Vijayakumar
Vijayakumar, Sethu
Load estimation and control using learned dynamics models Georgios Petkos and Sethu Vijayakumar with their robustness in light of imperfect, intermediate dynamic models. I. INTRODUCTION Adaptive control the learned dynamics for control. In Section IV, we see how from a set of learned models with known inertial
Direct Modeling of Envelope Dynamics in Resonant Inverters Yan Yin, Regan Zane, Robert Erickson
to facilitate optimized controller design. Several approaches are available to model the envelope dynamicsDirect Modeling of Envelope Dynamics in Resonant Inverters Yan Yin, Regan Zane, Robert Erickson- This paper provides a direct dynamic modeling approach for envelope signals in resonant inverters driven
Best practices for system dynamics model design and construction with powersim studio.
Malczynski, Leonard A.
2011-06-01T23:59:59.000Z
This guide addresses software quality in the construction of Powersim{reg_sign} Studio 8 system dynamics simulation models. It is the result of almost ten years of experience with the Powersim suite of system dynamics modeling tools (Constructor and earlier Studio versions). It is a guide that proposes a common look and feel for the construction of Powersim Studio system dynamics models.
Modelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models
Bath, University of
Modelling the e#ects of air pollution on health using Bayesian Dynamic Generalised Linear Models 1 Introduction The potential detrimental e#ects of ambient air pollution is a major issue in public (2004)). Large multicity studies such as `Air pollution and health: a European approach' (APHEA
User Guide for PV Dynamic Model Simulation Written on PSCAD Platform
Muljadi, E.; Singh, M.; Gevorgian, V.
2014-11-01T23:59:59.000Z
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.
Use dynamic simulation to model HPU reactor depressuring
Ernest, J.B.; Depew, C.A. (Fluor Daniel, Inc., Irvine, CA (United States))
1995-01-01T23:59:59.000Z
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.
Eulerian hydrocode modeling of a dynamic tensile extrusion experiment (u)
Burkett, Michael W [Los Alamos National Laboratory; Clancy, Sean P [Los Alamos National Laboratory
2009-01-01T23:59:59.000Z
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.
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
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)
2014-11-07T23:59:59.000Z
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.
Multiphase flow in the advanced fluid dynamics model
Bohl, W.R.; Wilhelm, D.; Berthier, J.; Parker, F.P.; Ichikawa, S.; Goutagny, L.; Ninokata, H.
1988-01-01T23:59:59.000Z
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.
Computational fluid dynamic modeling of fluidized-bed polymerization reactors
Rokkam, Ram [Ames Laboratory
2012-11-02T23:59:59.000Z
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.
Parameter Estimation of Dynamic Air-conditioning Component Models Using Limited Sensor Data
Hariharan, Natarajkumar
2011-08-08T23:59:59.000Z
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 role in the system model...
Nucleon-nucleon interaction in the chromodielectric soliton model: Dynamics
Pepin, S.; Stancu, F. [Universite de Liege, Institut de Physique B.5, Sart-Tilman, B-4000 Liege 1 (Belgium)] [Universite de Liege, Institut de Physique B.5, Sart-Tilman, B-4000 Liege 1 (Belgium); Koepf, W. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Tel Aviv (Israel)] [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Tel Aviv (Israel); Wilets, L. [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States)] [Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States)
1996-03-01T23:59:59.000Z
The present work is an extension of a previous study of the nucleon-nucleon interaction based on the chromodielectric soliton model. The former approach was static, leading to an adiabatic potential. Here we perform a dynamical study in the framework of the generator coordinate method. In practice we derive an approximate Hill-Wheeler differential equation and obtain a local nucleon-nucleon potential as a function of a mean generator coordinate. This coordinate is related to an effective separation distance between the two nucleons by a Fujiwara transformation. This latter relationship is especially useful in studying the quark substructure of light nuclei. We investigate the explicit contribution of the one-gluon exchange part of the six-quark Hamiltonian to the nucleon-nucleon potential, and we find that the dynamics are responsible for a significant part of the short-range {ital N}-{ital N} repulsion. {copyright} {ital 1996 The American Physical Society.}
Model for Aggregated Water Heater Load Using Dynamic Bayesian Networks
Vlachopoulou, Maria; Chin, George; Fuller, Jason C.; Lu, Shuai; Kalsi, Karanjit
2012-07-19T23:59:59.000Z
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.
Explorations in combining cognitive models of individuals and system dynamics models of groups.
Backus, George A.
2008-07-01T23:59:59.000Z
This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.
Li, Yangmin
Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving on a Slope 1 Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving manipulator, neural-fuzzy control, nonholonomic. 1. INTRODUCTION Intelligent and autonomous mobile
A simple microscopic model for the dynamics of adhesive failure
Dominic Vella; L. Mahadevan
2005-12-27T23:59:59.000Z
We consider a microscopic model for the failure of soft adhesives in tension based on ideas of bond rupture under dynamic loading. Focusing on adhesive failure under loading at constant velocity, we demonstrate that bi-modal curves of stress against strain may occur due to effects of finite polymer chain or bond length and characterise the loading conditions under which such bi-modal behaviour is observed. The results of this analysis are in qualitative agreement with experiments performed on unconfined adhesives in which failure does not occur by cavitation.
Validation of DWPF MOG dynamics model -- Phase 1
Choi, A.S.
1996-09-23T23:59:59.000Z
The report documents the results of a study to validate the DWPF melter off-gas system dynamics model using the data collected during the Waste Qualification Runs in 1995. The study consisted of: (1) calibration of the model using one set of melter idling data, (2) validation of the calibrated model using three sets of steady feeding and one set of transient data, and (3) application of the validated model to simulate the melter overfeeding incident which took place on 7/5.95. All the controller tuning constants and control logic used in the validated model are identical to those used in the DCS in 1995. However, the model does not reflect any design and/or operational changes made in 1996 to alleviate the glass pouring problem. Based on the results of the overfeeding simulation, it is concluded that the actual feed rates during that incident were about 2.75 times the indicated readings and that the peak concentration of combustible gases remained below 15% of the lower flammable limit during the entire one-hour duration.
A LUMPED-PARAMETER DYNAMIC MODEL OF A THERMAL REGENERATOR FOR FREE-PISTON STIRLING ENGINES
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
Designability, thermodynamic stability, and dynamics in protein folding: A lattice model study
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
Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model
Rossi, R; Gallagher, B; Neville, J; Henderson, K
2011-11-11T23:59:59.000Z
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.
Learning Multiple Models of Non-Linear Dynamics for Control under Varying Contexts
Petkos, Georgios; Toussaint, Marc; Vijayakumar, Sethu
For stationary systems, efficient techniques for adaptive motor control exist which learn the system’s inverse dynamics online and use this single model for control. However, in realistic domains the system dynamics often ...
Griffith, Daniel Todd
2005-02-17T23:59:59.000Z
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 ...
Dynamic chirality in the interacting boson fermion-fermion model
Brant, S. [Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Tonev, D. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Institute for Nuclear Research and Nuclear Energy, BAS, 1784 Sofia (Bulgaria); De Angelis, G. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Ventura, A. [Ente per le Nuove tecnologie, l'Energia e l'Ambiente, I-40129 Bologna and Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (Italy)
2008-09-15T23:59:59.000Z
The chiral interpretation of twin bands in odd-odd nuclei was investigated in the interacting boson fermion-fermion model. The analysis of the wave functions has shown that the possibility for angular momenta of the valence proton, neutron and core to find themselves in the favorable, almost orthogonal geometry is present, but not dominant. Such behavior is found to be similar in nuclei where both the level energies and the electromagnetic decay properties display the chiral pattern, as well as in those where only the level energies of the corresponding levels in the twin bands are close together. The difference in the structure of the two types of chiral candidates nuclei can be attributed to different {beta} and {gamma} fluctuations, induced by the exchange boson-fermion interaction of the interacting boson fermion-fermion model. In both cases the chirality is weak and dynamic.
Modeling the Dynamic Behavior of a Single Pile in Dry Sand using a new p-y Material Model
Choi, JungIn; Brandenberg, Scott J; Kim, MyoungMo
2013-01-01T23:59:59.000Z
of dynamic pile behavior by centrifuge tests consideringof KOCED geotechnical centrifuge and its shear wave velocitysurface plasticity theory. Centrifuge model data analyzed
DYNAMIC MODELLING OF LIVING ANIONIC SOLUTION POLYMERIZATION OF STYRENE/BUTADIENE/DIVINYLBENZENE
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
Parameter Estimation of Dynamic Air-conditioning Component Models Using Limited Sensor Data
Hariharan, Natarajkumar
2011-08-08T23:59:59.000Z
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 ...
Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics
Xu, Chonggang [Los Alamos National Laboratory (LANL); Fisher, Rosie [National Center for Atmospheric Research (NCAR); Wullschleger, Stan D [ORNL; Wilson, Cathy [Los Alamos National Laboratory (LANL); Cai, Michael [Los Alamos National Laboratory (LANL); McDowell, Nathan [Los Alamos National Laboratory (LANL)
2012-01-01T23:59:59.000Z
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.
VISION -- A Dynamic Model of the Nuclear Fuel Cycle
J. J. Jacobson; A. M. Yacout; S. J. Piet; D. E. Shropshire; G. E. Matthern
2006-02-01T23:59:59.000Z
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.
MODEST: modeling stellar evolution and (hydro)dynamics
Piet Hut
2003-09-15T23:59:59.000Z
Simulations of dense stellar systems currently face two major hurdles, one astrophysical and one computational. The astrophysical problem lies in the fact that several major stages in binary evolution, such as common envelope evolution, are still poorly understood. The best we can do in these cases is to parametrize our ignorance, in a way that is reminiscent of the introduction of a mixing length to describe convection in a single star, or an alpha parameter in modeling an accretion disk. The hope is that by modeling a whole star cluster in great detail, and comparing the results to the wealth of observational data currently available, we will be able to constrain the parameters that capture the unknown physics. The computational problem is one of composition: while we have accurate computer codes for modeling stellar dynamics, stellar hydrodynamics, and stellar evolution, we currently have no good way to put all this knowledge together in a single software environment. A year ago, a loosely-knit organization was founded to address these problems, MODEST for MOdeling DEnse STellar systems, with nine working groups and a series of meetings that are held every half year. This report reviews the first year of this initiative. Much more detail can be found on the MODEST web site http://www.manybody.org/modest.html .
Paris-Sud XI, Université de
Transitional Modeling of Building Heating Energy Demand Using Artificial1 Neural Network2 Subodh Paudel a artificial12 neural network. In addition, novel pseudo dynamic transitional model is introduced, which Institution15 building and compared its results with static and other pseudo dynamic neural network models
Object-oriented Dynamics Modeling for Legged Robot Trajectory Optimization and Control
Stryk, Oskar von
Object-oriented Dynamics Modeling for Legged Robot Trajectory Optimization and Control Robert. To facilitate the investigation of new concepts of nonlinear model-based optimization and control methods also-level specification of multibody dynamics models using component libraries serves as a basis for generation
Technical Note Comparing Dynamic Causal Models using AIC, BIC and Free Energy
Penny, Will
Technical Note Comparing Dynamic Causal Models using AIC, BIC and Free Energy W.D. Penny Wellcome) and Dynamic Causal Models (DCMs). We find that the Free Energy has the best model selection ability, to instead score DCMs using the Free Energy (Friston et al., 2007a). However, until now there has been
Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances
Tsiotras, Panagiotis
Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances C. Canudas we derive a new dynamic friction force model for the longitudinal road/tire interaction for wheeled-point friction problems, called the LuGre model [1]. By assuming a con- tact patch between the tire
THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL
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
THE ROAD AHEAD FOR ENERGY-ECONOMY POLICY MODELS: INTEGRATING MARKET DYNAMICS,
THE ROAD AHEAD FOR ENERGY-ECONOMY POLICY MODELS: INTEGRATING MARKET DYNAMICS, EXPECTATIONS of Research Project: The Road Ahead For Energy-Economy Policy Models: Integrating Market Dynamics of Resource and Environmental Management Date Approved: ii #12;Abstract Energy-economy models have emerged
Ris-R-1400(EN) Dynamic wind turbine models in power
Risø-R-1400(EN) Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D system simulation tool - DIgSILENT 7 2.2 Built-in models in DIgSILENT 8 2.2.1 Electrical machinery 8 2 the dynamic wind turbine models imple- mented in the power system simulation tool DIgSILENT (Version 12
Dynamical modeling of the Deep Impact dust ejecta cloud
Tanyu Bonev; Nancy Ageorges; Stefano Bagnulo; Luis Barrera; Hermann B{ö}hnhardt; Olivier Hainaut; Emmanuel Jehin; Hans-Ullrich K{ä}ufl; Florian Kerber; Gaspare LoCurto; Jean Manfroid; Olivier Marco; Eric Pantin; Emanuela Pompei; Ivo Saviane; Fernando Selman; Chris Sterken; Heike Rauer; Gian Paolo Tozzi; Michael Weiler
2007-03-21T23:59:59.000Z
The collision of Deep Impact with comet 9P/Tempel 1 generated a bright cloud of dust which dissipated during several days after the impact. The brightness variations of this cloud and the changes of its position and shape are governed by the physical properties of the dust grains. We use a Monte Carlo model to describe the evolution of the post-impact dust plume. The results of our dynamical simulations are compared to the data obtained with FORS2, the FOcal Reducer and low dispersion Spectrograph for the VLT of the European Southern Observatory (ESO), to derive the particle size distribution and the total amount of material contained in the dust ejecta cloud.
EPR pairing dynamics in Hubbard model with resonant $U$
X. Z. Zhang; Z. Song
2015-04-28T23:59:59.000Z
We study the dynamics of the collision between two fermions in Hubbard model with on-site interaction strength $U$. The exact solution shows that the scattering matrix for two-wavepacket collision is separable into two independent parts, operating on spatial and spin degrees of freedom, respectively. The S-matrix for spin configuration is equivalent to that of Heisenberg-type pulsed interaction with the strength depending on $U$ and relative group velocity $\\upsilon _{r}$. This can be applied to create distant EPR pair, through a collision process for two fermions with opposite spins in the case of $\\left\\vert \\upsilon _{r}/U\\right\\vert =1$,\\ without the need for temporal control and measurement process. Multiple collision process for many particles is also discussed.
Hydro-dynamical models for the chaotic dripping faucet
P. Coullet; L. Mahadevan; C. S. Riera
2004-08-20T23:59:59.000Z
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.
Some optical and dynamical phenomena in the Rindler model
E. Birsin; W. Hasse
2014-11-15T23:59:59.000Z
In Rindler's model of a uniformly accelerated reference frame we analyze the apparent shape of rods and marked light rays for the case that the observers as well as the rods and the sources of light are at rest with respect to the Rindler observers. Contrary to the expectation suggested by the strong principle of equivalence, there is no apparent "bending down" of a light ray with direction transversal to the direction of acceleration, but a straight rod oriented orthogonal to the direction of acceleration appears bended "upwards". These optical phenomena are in accordance with the dynamical experience of observers guided by a straight track or a track curved in the same way as the marked light ray, respectively: While the former observer feels a centrifugal force directed "downwards", the centrifugal force for the latter vanishes. The properties of gyroscope transport along such tracks are correspondingly.
Description of waste pretreatment and interfacing systems dynamic simulation model
Garbrick, D.J.; Zimmerman, B.D.
1995-05-01T23:59:59.000Z
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.
Comparing the escape dynamics in tidally limited star cluster models
Zotos, Euaggelos E
2015-01-01T23:59:59.000Z
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...
Comparing the escape dynamics in tidally limited star cluster models
Euaggelos E. Zotos
2015-08-21T23:59:59.000Z
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.
Como, Giacomo
Automating efficiency-targeted approximations in modelling and simulation tools: dynamic decoupling (classical) efficiency-targeted approximation tech- niques, within a unified framework. Some application
A model for coupling within-host and between-host dynamics in an ...
2011-12-20T23:59:59.000Z
Abstract Studies on the modeling of the coupled dy- namics of infectious diseases at both the population level (the epidemic process or between-host dynamics).
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
Emerging disease dynamics in a model coupling within-host and ...
Xiuli Cen
2014-08-27T23:59:59.000Z
Aug 2, 2014 ... Immunological models consider the within-host dynamics independent of the interactions between hosts (e.g., De Leenheer and Smith, 2003;.
Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.
Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan
2011-06-01T23:59:59.000Z
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.
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
Application of Extended Kalman Filter Techniques for Dynamic Model Parameter Calibration
Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Bo
2009-07-26T23:59:59.000Z
Abstract -Phasor measurement has previously been used for sub-system model validation, which enables rigorous comparison of model simulation and recorded dynamics and facilitates identification of problematic model components. Recent work extends the sub-system model validation approach with a focus on how model parameters may be calibrated to match recorded dynamics. In this paper, a calibration method using Extended Kalman Filter (EKF) technique is proposed. This paper presents the formulation as well as case studies to show the validity of the EKF-based parameter calibration method. The proposed calibration method is expected to be a cost-effective means complementary to traditional equipment testing for improving dynamic model quality.
Mixtures of Predictive Linear Gaussian Models for Nonlinear Stochastic Dynamical Systems
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
A Dynamic Solar Core model: the SSM-like solution
Attila Grandpierre
1998-08-31T23:59:59.000Z
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
Adaptive Optimal Feedback Control with Learned Internal Dynamics Models
Mitrovic, Djordje; Klanke, Stefan; Vijayakumar, Sethu
2010-01-01T23:59:59.000Z
, have focused on the case of non-linear, but still analytically available, dynamics. For realistic control systems, however, the dynamics may often be unknown, difficult to estimate, or subject to frequent systematic changes. In this chapter, we combine...
A Dynamic Solar Core Model: the Deviant Temperatures Approach
Attila Grandpierre
1998-08-31T23:59:59.000Z
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
Ultrafast Structural Dynamics in Combustion Relevant Model Systems
Weber, Peter M. [Brown University
2014-03-31T23:59:59.000Z
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
Stochastic model for aerodynamic force dynamics on wind turbine blades in unsteady wind inflow
Luhur, Muhammad Ramzan; Kühn, Martin; Wächter, Matthias
2015-01-01T23:59:59.000Z
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.
DYNAMIC MODELING AND CONTROL OF REACTIVE DISTILLATION FOR HYDROGENATION OF BENZENE
Aluko, Obanifemi
2010-01-16T23:59:59.000Z
This work presents a modeling and control study of a reactive distillation column used for hydrogenation of benzene. A steady state and a dynamic model have been developed to investigate control structures for the column. The most important aspects...
Networking technology adoption : system dynamics modeling of fiber-to-the-home
Kelic, Andjelka, 1972-
2005-01-01T23:59:59.000Z
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 ...
AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS
Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang
2011-01-01T23:59:59.000Z
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.
Multiple Model Robust Dynamic Programming Eric C. Whitman and Christopher G. Atkeson
-- Modeling error is a common problem for model- based control techniques. We present multiple model dynamic programming (MMDP) as a method to generate controllers that are robust to modeling error. Our method generates controllers that are approximately optimal for a collection of models, thereby forcing the controller
Data-based Subsystem Identification for Dynamic Model Updating Steven Gillijns and Bart De Moor
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
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
Protecting the African elephant: A dynamic bioeconomic model of ivory trade
Protecting the African elephant: A dynamic bioeconomic model of ivory trade G. Cornelis van Kooten Accepted 25 May 2008 Available online 7 July 2008 Keywords: Economics Elephant conservation Ivory trade ban Mathematical programming Trade quota A B S T R A C T A dynamic bioeconomic model of ivory trade is used
GLOBAL STABILITY FOR A VIRUS DYNAMICS MODEL WITH NONLINEAR INCIDENCE OF INFECTION AND REMOVAL
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
ROLE OF VEHICLE DYNAMIC MODELING FIDELITY WITH HAPTIC COLLABORATION IN STEER BY WIRE
Krovi, Venkat
ROLE OF VEHICLE DYNAMIC MODELING FIDELITY WITH HAPTIC COLLABORATION IN STEER BY WIRE SYSTEMS control back to the driver. Candidate solutions for mimicking the steering feel have ranged from direct torque prediction schemes based on mathematical dynamics models (of tire-road, suspension, power-steering
Multi-Point Contact Models for Dynamic Self-Righting of a Hexapod
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
Sand dune dynamics and climate change: A modeling H. Yizhaq,1
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: Yizhaq, H., Y. Ashkenazy, and H. Tsoar (2009), Sand dune dynamics and climate change: A modeling approach
Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results
Tsiotras, Panagiotis
Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results C. Canudas dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is val- idated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps
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
Gupta, Rajesh
A Model Checking Approach to Evaluating System Level Dynamic Power Management Policies for Embedded, and laptops, controlling power dissipation is an important system design issue [2]. This is either because enforced at the system level. In [3], a system modeling ap- proach for dynamic power management strategy
AN IMPROVED DYNAMIC MODEL FOR THE STUDY OF A FLEXIBLE PAVEMENT
Avignon et des Pays de Vaucluse, Université de
AN IMPROVED DYNAMIC MODEL FOR THE STUDY OF A FLEXIBLE PAVEMENT A. El Ayadi 1 , B. Picoux 1 , G to study a Falling Weight Deectometer test conducted on a exible pavement. These dynamic models take with in situ measurements recorded on an instrumented pavement; such a comparison has indicated the importance
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
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
A Dynamic Model for Phase Transformations in 3D Samples of Shape Memory Alloys
Melnik, Roderick
A Dynamic Model for Phase Transformations in 3D Samples of Shape Memory Alloys D.R. Mahapatra and R Introduction Modelling of dynamics of phase transformations (PT) in Shape Memory Al- loys (SMAs) under which assist the researchers in designing new materials and devices by harnessing the shape memory
Coupled thermodynamic-dynamic semi-analytical model of Free Piston Stirling engines
Formosa, Fabien
2013-01-01T23:59:59.000Z
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...
Integrated dynamic landscape analysis and modeling system (IDLAMS) : installation manual.
Li, Z.; Majerus, K. A.; Sundell, R. C.; Sydelko, P. J.; Vogt, M. C.
1999-02-24T23:59:59.000Z
The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) is a prototype, integrated land management technology developed through a joint effort between Argonne National Laboratory (ANL) and the US Army Corps of Engineers Construction Engineering Research Laboratories (USACERL). Dr. Ronald C. Sundell, Ms. Pamela J. Sydelko, and Ms. Kimberly A. Majerus were the principal investigators (PIs) for this project. Dr. Zhian Li was the primary software developer. Dr. Jeffrey M. Keisler, Mr. Christopher M. Klaus, and Mr. Michael C. Vogt developed the decision analysis component of this project. It was developed with funding support from the Strategic Environmental Research and Development Program (SERDP), a land/environmental stewardship research program with participation from the US Department of Defense (DoD), the US Department of Energy (DOE), and the US Environmental Protection Agency (EPA). IDLAMS predicts land conditions (e.g., vegetation, wildlife habitats, and erosion status) by simulating changes in military land ecosystems for given training intensities and land management practices. It can be used by military land managers to help predict the future ecological condition for a given land use based on land management scenarios of various levels of training intensity. It also can be used as a tool to help land managers compare different land management practices and further determine a set of land management activities and prescriptions that best suit the needs of a specific military installation.
Rate models with delays and the dynamics of large networks of spiking neurons
Roxin, Alex
1 Rate models with delays and the dynamics of large networks of spiking neurons Alex Roxin, Nicolas in a reduced rate model provided that the interactions are delayed. §1. Introduction Simplified models of large transformation through a sigmoidal input-output transfer function. Network models of spiking neurons can
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
JACKSON VL
2011-08-31T23:59:59.000Z
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.
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 ...
Be Migration Studies at JET and their Interpretation by an Integrated Model for Plasma Impurity Transport and Wall Composition Dynamics
Modeling the dynamics and depositional patterns of sandy rivers
Jerolmack, Douglas J
2006-01-01T23:59:59.000Z
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 ...
Modeling Robot Dynamic Performance for Endpoint Force Control
Eppinger, Steven D.
1988-09-01T23:59:59.000Z
This research aims to understand the fundamental dynamic behavior of servo-controlled machinery in response to various types of sensory feedback. As an example of such a system, we study robot force control, a scheme ...
Dynamic reduced order modeling of entrained flow gasifiers
Monaghan, Rory F. D. (Rory Francis Desmond)
2010-01-01T23:59:59.000Z
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 ...
Multiscale Modeling of Process Dynamics and Microstructure Development...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of Process Dynamics and Microstructure Development in Laser-based Keyhole Welding and Additive Manufacturing Jun 05 2015 10:00 AM - 11:00 AM Wenda Tan, University of Utah, Salt...
Chi, K C; Reiner, David; Nuttall, William J
www.eprg.group.cam.ac.uk E P R G W O R K IN G P A P E R N O N -T E C H N IC A L S U M M A R Y DYNAMICS OF THE UK NATURAL GAS INDUSTRY: SYSTEM DYNAMICS MODELLING AND LONG-TERM ENERGY POLICY ANALYSIS EPRG Working Paper 0913... Cambridge Working Paper in Economics 0922 Kong Chyong Chi , David M. Reiner and William J. Nuttall The UK offshore natural gas and oil industry has a long and successful history and has been said to represent the pride of UK...
Model-based Trajectory Control of Robots with Pneumatic Actuator Dynamics
Tedrake, Russ
movements despite being equipped with actuators (human muscles) that have band- width limitations similar. Motion planning has been successfully applied to a number of dynamic legged robots [13Model-based Trajectory Control of Robots with Pneumatic Actuator Dynamics Ryuma Niiyama Abstract
Modeling the dynamic component of the geoid and topography of Venus
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
Static and dynamic length scales in a simple glassy plaquette model Robert L. Jack,1
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
Calibration of CDO Tranches with the Dynamical Generalized-Poisson Loss Model
Brigo, Damiano
Calibration of CDO Tranches with the Dynamical Generalized-Poisson Loss Model (updated shortened, and consistent calibration to quoted index CDO tranches and tranchelets for several maturities is feasible, as we dynamics, investigating calibration improve- ments and stability. JEL classification code: G13. AMS
A Formal Framework for Modeling and Analysis of System-Level Dynamic Power Management
Ha, Dong S.
A Formal Framework for Modeling and Analysis of System-Level Dynamic Power Management Shrirang, tlmartin, ha}@vt.edu Abstract Recent advances in Dynamic Power Management (DPM) tech- niques have resulted in designs that support a rich set of power management options, both at the hardware and software levels
Keppens, J; 10.1613/jair.1335
2011-01-01T23:59:59.000Z
The predominant knowledge-based approach to automated model construction, compositional modelling, employs a set of models of particular functional components. Its inference mechanism takes a scenario describing the constituent interacting components of a system and translates it into a useful mathematical model. This paper presents a novel compositional modelling approach aimed at building model repositories. It furthers the field in two respects. Firstly, it expands the application domain of compositional modelling to systems that can not be easily described in terms of interacting functional components, such as ecological systems. Secondly, it enables the incorporation of user preferences into the model selection process. These features are achieved by casting the compositional modelling problem as an activity-based dynamic preference constraint satisfaction problem, where the dynamic constraints describe the restrictions imposed over the composition of partial models and the preferences correspond to thos...
A Numerical Model For The Dynamics Of Pyroclastic Flows At Galeras...
model is applied to one of the slopes of Galeras Volcano to show: (1) the temperature evolution with the time; (2) dynamic pressure change; and (3) particle concentration along the...
Rojas Paico, Danny H.
2001-01-01T23:59:59.000Z
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 ...
Dynamic soil-structure interaction-comparison of FEM model with experimental results
Srinivasan, Palanivel Rajan
2000-01-01T23:59:59.000Z
to represent twenty different laboratory experiments. The results of these models are compared with results available from extensive experimental dynamic testing on a geotechnical centrifuge. Though the various results from the finite element analysis...
A Nonlinear Continuous Time Optimal Control Model of Dynamic Pricing and Inventory Control with no
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
Seagraves, Andrew Nathan
2010-01-01T23:59:59.000Z
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 ...
Dynamic First-Principles Molecular-Scale Model for Solid Oxide Fuel Cells V. Hugo Schmidt
Dynamic First-Principles Molecular-Scale Model for Solid Oxide Fuel Cells V. Hugo Schmidt vs. current density i characteristics applies both to the Solid Oxide Fuel Cell (SOFC) and Solid
Dynamic Modeling and Wavelet-Based Multi-Parametric Tuning and Validation for HVAC Systems
Liang, Shuangshuang
2014-07-10T23:59:59.000Z
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 ...
Paris-Sud XI, Université de
Dynamic Model for Assessing Impact of Regeneration Actions on System Availability: Application) Key Words: failure, damage, regeneration, availability assessment, stochastic activity networks, Monte Carlo simulations SUMMARY & CONCLUSIONS Availability is a determining factor in systems characterization
Nonrigid Motion Analysis Based on Dynamic Refinement of Finite Element Models
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 betweenÃPhysically-based vision, deformable models, nonrigid motion analysis, biomedical applications, finite element analysis. Ã¦
Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion C. Julcoura
Paris-Sud XI, Université de
Dynamic modeling of three-phase upflow fixed-bed reactor including pore diffusion C. Julcoura , R-phase upflow fixed-bed reactor are investigated using a non-isothermal heterogeneous model including gas not limiting, so that the simplest model predicts accurately the transient reactor behavior. Keywords: fixed-bed
New trends in vehicle dynamics: from modelling to control. Olivier SENAME
Paris-Sud XI, Université de
New trends in vehicle dynamics: from modelling to control. Olivier SENAME GIPSA-lab - Department approaches such as H approach for Linear Parameter Varying systems and Model predictive control have shown methods for modelling and control of subsystems and of the vehicle. The session will be organized
Computational Fluid Dynamics Modeling of a Lithium/Thionyl Chloride Battery with Electrolyte Flow
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
Automated Modeling of Dynamic Reliability Block Diagrams Using Colored Petri Nets
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
Development of a Data Driven Dynamic Model for a Plasma Etching Reactor Michael Nikolaoua)
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
Sleep Dynamics and Seizure Control in a Mesoscale Cortical Model
Lopour, Beth Ann
2009-01-01T23:59:59.000Z
Contributions . . . . . . . . . 2 Mesoscale Cortical Modelstates in h e from the mesoscale cortical model, here- afterand Seizure Control in a Mesoscale Cortical Model by Beth
Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Steve
2013-05-01T23:59:59.000Z
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.
Characteristics of identifying linear dynamic models from impulse response data using Prony analysis
Trudnowski, D.J.
1992-12-01T23:59:59.000Z
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.
Characteristics of identifying linear dynamic models from impulse response data using Prony analysis
Trudnowski, D.J.
1992-12-01T23:59:59.000Z
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.
Modeling the star formation in galaxies using the Chemo - dynamical SPH code
Peter Berczik
2000-07-19T23:59:59.000Z
A new Chemo - Dynamical Smoothed Particle Hydrodynamic (CD - SPH) code is presented. The disk galaxy is described as a multi - fragmented gas and star system, embedded in a cold dark matter halo. The star formation (SF) process, SNII, SNIa and PN events as well as chemical enrichment of gas have been considered within the framework of the standard SPH model. Using this model we describe the dynamical and chemical evolution of triaxial disk - like galaxies. It is found that such approach provides a realistic description of the process of formation, chemical and dynamical evolution of disk galaxies over a cosmological timescale.
Wang, Shaobu; Lu, Shuai; Zhou, Ning; Lin, Guang; Elizondo, Marcelo A.; Pai, M. A.
2014-09-04T23:59:59.000Z
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.
Chapter 18: Understanding the Developing Cellulosic Biofuels Industry through Dynamic Modeling
Newes, E.; Inman, D.; Bush, B.
2011-01-01T23:59:59.000Z
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.
Humanoid Walking Robot: Modeling, Inverse Dynamics, and Gain Scheduling Control
Williams II, Robert L.
and Robert L. Williams II Department of Mechanical Engineering Ohio University, Athens, OH 45701 Revised trajectories, recorded from real human walking cycle data. Kinematic and dynamic analysis is discussed. This analysis is accompanied by a comparison with available experimental data. Finally, an inverse plant
Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint
Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.
2013-03-01T23:59:59.000Z
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.
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
Liese, Eric [U.S. DOE; Zitney, Stephen E. [U.S. DOE
2013-01-01T23:59:59.000Z
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.
Gedeon, Tomas
, from those appearing in physiology and ecology to Earth systems modeling, often experience critical
A nonlinear dynamic model of a once-through, helical-coil steam generator
Abdalla, M.A. [Oak Ridge Inst. for Science and Education, TN (United States)
1993-07-01T23:59:59.000Z
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.
Modeling Red Blood Cell and Iron Dynamics in Patients with Chronic Kidney Disease
Modeling Red Blood Cell and Iron Dynamics in Patients with Chronic Kidney Disease H. T. Banks1, that stimulates red blood cell (RBC) production. Without intervention, patients suffer from anemia. Patients treatment. Keywords: mathematical model, mathematical biology, erythropoiesis, erythrocyte, red blood cell
Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll form 17 October 2000; accepted 1 June 2001 Abstract A remotely sensed image of Loch Leven, a shallow in the remotely sensed image. It is proposed that CFD modelling benefits the interpretation of remotely sensed
El Nino duration time (month) Dynamic coupling of an ENSO model to the
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
Discrete molecular dynamics studies of the folding of a protein-like model
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
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness
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
Generalized models as a universal approach to the analysis of nonlinear dynamical systems
Thilo Gross; Ulrike Feudel
2006-01-29T23:59:59.000Z
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.
A 3D dynamical biomechanical tongue model to study speech motor control
Paris-Sud XI, Université de
- 1 - A 3D dynamical biomechanical tongue model to study speech motor control Jean-Michel Gérard1 about speech motor control. Tissue elastic properties are accounted for in Finite Element Modeling (FEM shape are presented and analyzed. #12;- 3 - I.Introduction The study of human motor control implies
Data-driven Modeling of Metal-oxide Sensors with Dynamic Bayesian Networks
Gutierrez-Osuna, Ricardo
to model the transient response of MOX sensors modulated with a sequence of voltage steps. Analytical models of MOX sensors are usually built based on the physico-chemical properties of the sensing materials. Our results show that DBNs can accurately predict the dynamic response of MOX sensors, as well
ForPeerReview Drug user dynamics: a compartmental model of drug users
Triolo, Livio
ForPeerReview Only Drug user dynamics: a compartmental model of drug users for scenario analyses Journal: Drugs: Education, Prevention & Policy Manuscript ID: CDEP-2012-0094.R1 Manuscript Type: Original papers Keywords: Drug use, Epidemics, Compartmental modeling, Scenario analysis, Evaluation, Drug policy
Liquid Water Dynamics in a Model Polymer Electrolyte Fuel Cell Flow Channel
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
Mehmood et al. Paper No. 03-2158 1 Modeling Car-following Using System Dynamics
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
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
Dynamic Topic Models David M. Blei BLEI@CS.PRINCETON.EDU
Blei, David M.
Dynamic Topic Models David M. Blei BLEI@CS.PRINCETON.EDU Computer Science Department, Princeton patterns of words in document collec- tions using hierarchical probabilistic models (Blei et al., 2003; McCallum et al., 2004; Rosen-Zvi et al., 2004; Grif- fiths and Steyvers, 2004; Buntine and Jakulin, 2004; Blei
Affinely-rigid body and oscillatory dynamical models on GL(2,R)
Agnieszka Martens; Jan J. S?awianowski
2010-11-23T23:59:59.000Z
Discussed is a model of the two-dimensional affinely-rigid body with the double dynamical isotropy. We investigate the systems with potential energies for which the variables can be separated. The special stress is laid on the model of the harmonic oscillator potential and certain anharmonic alternatives. Some explicit solutions are found on the classical, quasiclassical (Bohr-Sommerfeld) and quantum level.
Dynamics of cerebral blood flow regulation explained using a lumped parameter model
Olufsen, Mette Sofie
Dynamics of cerebral blood flow regulation explained using a lumped parameter model METTE S, and Harvard Medical School, Boston, Massachusetts 02131 Received 22 May 2001; accepted in final form 10 regulation explained using a lumped parameter model. Am J Physiol Regulatory Integra- tive Comp Physiol 282
Analysis of a Darcy flow model with a dynamic pressure saturation relation \\Lambda
Hulshof, Joost
equations modelling the flow. In the standard approach for two phase flows, such as oilwater or airwater mixtures, one combines the mass conservation equations and Darcy's law for the separate phasesAnalysis of a Darcy flow model with a dynamic pressure saturation relation \\Lambda Josephus Hulshof
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
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
Phase Field Dynamic Modelling of Shape Memory Alloys Based on Isogeometric Analysis
Gomez, Hector
Phase Field Dynamic Modelling of Shape Memory Alloys Based on Isogeometric Analysis Rakesh Dhote1 transformations, phase-field model, Ginzburg-Landau theory, nonlinear thermo-elasticity. Abstract. Shape Memory. Introduction Shape Memory Alloys have attracted considerable attention of physicists, engineers and mathemati
Dynamics of an age-structured metapopulation model
2005-10-28T23:59:59.000Z
of these types of age distributions into the model may provide more realistic predictions for .... It is clear that K2(a) represents the production of newly occupied ...
Dynamic Models for Wind Turbines and Wind Power Plants
Singh, M.; Santoso, S.
2011-10-01T23:59:59.000Z
The primary objective of this report was to develop universal manufacturer-independent wind turbine and wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. To determine how realistic model performance is, the performance of one of the models (doubly-fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.
LECTURES ON DYNAMICS IN MODELS OF COARSENING AND COAGULATION
bath 11 2.4 Mean-field model of domain growth--the Gallay-Mielke transform 13 2.5 Proof of universal
Modeling the dynamics of a tracer particle in an elastic active gel
Isaac, E Ben; Visco, P; van Wijland, F; Gov, N S
2015-01-01T23:59:59.000Z
The internal dynamics of active gels, both in artificial (in-vitro) model systems and inside the cytoskeleton of living cells, has been extensively studied by experiments of recent years. These dynamics are probed using tracer particles embedded in the network of biopolymers together with molecular motors, and distinct non-thermal behavior is observed. We present a theoretical model of the dynamics of a trapped active particle, which allows us to quantify the deviations from equilibrium behavior, using both analytic and numerical calculations. We map the different regimes of dynamics in this system, and highlight the different manifestations of activity: breakdown of the virial theorem and equipartition, different elasticity-dependent "effective temperatures" and distinct non-Gaussian distributions. Our results shed light on puzzling observations in active gel experiments, and provide physical interpretation of existing observations, as well as predictions for future studies.
On preparation of viscous pore fluids for dynamic centrifuge modelling
Adamidis, O.; Madabhushi, S. P. G.
2014-11-21T23:59:59.000Z
dynamic cen- trifuge tests, the use of water as pore fluid can limit the generation of excess pore pressures in sand formations below gravel embankments, lowering the recorded crest settlement signif- icantly. Chian and Madabhushi [2010] exam- ined... with changing 4 1.2 1.6 2 2.4 2.8 3.2 0 40 80 120 160 200 Concentration [%] V is co si ty [m P a · s] measurements at 20?C best fit (8th order) best fit (power law) Stewart et al. [1998] Figure 2: Viscosity change with concentration 1.2 1.6 2 2.4 2.8 3.2 1...
Dynamic (G2) Model Design Document, 24590-WTP-MDD-PR-01-002, Rev. 12
Deng, Yueying; Kruger, Albert A.
2013-12-16T23:59:59.000Z
The Hanford Tank Waste Treatment and Immobilization Plant (WTP) Statement of Work (Department of Energy Contract DE-AC27-01RV14136, Section C) requires the contractor to develop and use process models for flowsheet analyses and pre-operational planning assessments. The Dynamic (G2) Flowsheet is a discrete-time process model that enables the project to evaluate impacts to throughput from eventdriven activities such as pumping, sampling, storage, recycle, separation, and chemical reactions. The model is developed by the Process Engineering (PE) department, and is based on the Flowsheet Bases, Assumptions, and Requirements Document (24590-WTP-RPT-PT-02-005), commonly called the BARD. The terminologies of Dynamic (G2) Flowsheet and Dynamic (G2) Model are interchangeable in this document. The foundation of this model is a dynamic material balance governed by prescribed initial conditions, boundary conditions, and operating logic. The dynamic material balance is achieved by tracking the storage and material flows within the plant as time increments. The initial conditions include a feed vector that represents the waste compositions and delivery sequence of the Tank Farm batches, and volumes and concentrations of solutions in process equipment before startup. The boundary conditions are the physical limits of the flowsheet design, such as piping, volumes, flowrates, operation efficiencies, and physical and chemical environments that impact separations, phase equilibriums, and reaction extents. The operating logic represents the rules and strategies of running the plant.
Modeling Temporal Activity Patterns in Dynamic Social Networks
Raghavan, Vasanthan; Galstyan, Aram; Tartakovsky, Alexander G
2013-01-01T23:59:59.000Z
The focus of this work is on developing probabilistic models for user activity in social networks by incorporating the social network influence as perceived by the user. For this, we propose a coupled Hidden Markov Model, where each user's activity evolves according to a Markov chain with a hidden state that is influenced by the collective activity of the friends of the user. We develop generalized Baum-Welch and Viterbi algorithms for model parameter learning and state estimation for the proposed framework. We then validate the proposed model using a significant corpus of user activity on Twitter. Our numerical studies show that with sufficient observations to ensure accurate model learning, the proposed framework explains the observed data better than either a renewal process-based model or a conventional uncoupled Hidden Markov Model. We also demonstrate the utility of the proposed approach in predicting the time to the next tweet. Finally, clustering in the model parameter space is shown to result in dist...
Dynamic modelling of chorded mitral valves inside left ventricle
Luo, Xiaoyu
model. This model allows us to investigate the influences of the flow vortex generated by the LV motion and swirls around in a clockwise fashion, forming a main clockwise vortex. This vortex persists through inside a tube, where the forward jet is accompanied by two vortices at each side. References
Cognitive Modeling Formulation and Analysis of Dynamic Systems
Bremen, Universität
trajectories produced by a local generator. #12;7 Logistic Growth Model Define p(t) as the probability affects the output (or, vice-versa, what inputs should be given to generate a desired output for the n-element binary valued lists. The state space of a brain model is the set of points contained
Dynamic modeling of a single-stage downward firing, entrained flow gasifier
Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.
2012-01-01T23:59:59.000Z
The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.
Advanced Modeling of Renewable Energy Market Dynamics: May 2006
Evans, M.; Little, R.; Lloyd, K.; Malikov, G.; Passolt, G.; Arent, D.; Swezey, B.; Mosey, G.
2007-08-01T23:59:59.000Z
This report documents a year-long academic project, presenting selected techniques for analysis of market growth, penetration, and forecasting applicable to renewable energy technologies. Existing mathematical models were modified to incorporate the effects of fiscal policies and were evaluated using available data. The modifications were made based on research and classification of current mathematical models used for predicting market penetration. An analysis of the results was carried out, based on available data. MATLAB versions of existing and new models were developed for research and policy analysis.
On the Characterization of Classical Dynamical Systems Using Supersymmetric Nonlinear $?$-models
A. J. Niemi; K. Palo
1995-03-13T23:59:59.000Z
We construct a two dimensional nonlinear $\\sigma$-model that describes the Hamiltonian flow in the loop space of a classical dynamical system. This model is obtained by equivariantizing the standard N=1 supersymmetric nonlinear $\\sigma$-model by the Hamiltonian flow. We use localization methods to evaluate the corresponding partition function for a general class of integrable systems, and find relations that can be viewed as generalizations of standard relations in classical Morse theory.
Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint
Wayman, E. N.; Sclavounos, P. D.; Butterfield, S.; Jonkman, J.; Musial, W.
2006-03-01T23:59:59.000Z
This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the frequency domain. This analysis was conducted by coupling the aerodynamics and structural dynamics code FAST [4] developed at NREL with the wave load and response simulation code WAMIT (Wave Analysis at MIT) [15] developed at MIT. Analysis tools were developed to consider coupled interactions between the wind turbine and the floating system. These include the gyroscopic loads of the wind turbine rotor on the tower and floater, the aerodynamic damping introduced by the wind turbine rotor, the hydrodynamic damping introduced by wave-body interactions, and the hydrodynamic forces caused by wave excitation. Analyses were conducted for two floater concepts coupled with the NREL 5-MW Offshore Baseline wind turbine in water depths of 10-200 m: the MIT/NREL Shallow Drafted Barge (SDB) and the MIT/NREL Tension Leg Platform (TLP). These concepts were chosen to represent two different methods of achieving stability to identify differences in performance and cost of the different stability methods. The static and dynamic analyses of these structures evaluate the systems' responses to wave excitation at a range of frequencies, the systems' natural frequencies, and the standard deviations of the systems' motions in each degree of freedom in various wind and wave environments. This article in various wind and wave environments. This article explores the effects of coupling the wind turbine with the floating platform, the effects of water depth, and the effects of wind speed on the systems' performance. An economic feasibility analysis of the two concepts was also performed. Key cost components included the material and construction costs of the buoy; material and installation costs of the tethers, mooring lines, and anchor technologies; costs of transporting and installing the system at the chosen site; and the cost of mounting the wind turbine to the platform. The two systems were evaluated based on their static and dynamic performance and the total system installed cost. Both systems demonstrated acceptable motions, and have estimated costs of $1.4-$1.8 million, not including the cost of the wind turbine, the power electronics, or the electrical transmission.
Model for Dynamic Self-Assembled Magnetic Surface Structures
M. Belkin; A. Glatz; A. Snezhko; I. S. Aranson
2010-02-02T23:59:59.000Z
We propose a first-principles model for self-assembled magnetic surface structures on the water-air interface reported in earlier experiments \\cite{snezhko2,snezhko4}. The model is based on the Navier-Stokes equation for liquids in shallow water approximation coupled to Newton equations for interacting magnetic particles suspended on the water-air interface. The model reproduces most of the observed phenomenology, including spontaneous formation of magnetic snake-like structures, generation of large-scale vortex flows, complex ferromagnetic-antiferromagnetic ordering of the snake, and self-propulsion of bead-snake hybrids. The model provides valuable insights into self-organization phenomena in a broad range of non-equilibrium magnetic and electrostatic systems with competing interactions.
Dynamics of the Oil Transition: Modeling Capacity, Costs, and Emissions
Brandt, Adam R.; Farrell, Alexander E.
2008-01-01T23:59:59.000Z
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.
Time consistency and risk averse dynamic decision models ...
2013-05-02T23:59:59.000Z
sistent models as we provide practitioners with an intuitive economic inter- pretation for the ... ning and financial engineering problems. Based on ... consistency is shown to be one basic requirement to get suitable optimal de- cisions, in ...
Stochastic Modeling and Analysis of Pathway Regulation and Dynamics
Zhao, Chen
2012-07-16T23:59:59.000Z
To effectively understand and treat complex diseases such as cancer, mathematical and statistical modeling is essential if one wants to represent and characterize the interactions among the different regulatory components ...
Stochastic Modeling and Analysis of Pathway Regulation and Dynamics
Zhao, Chen
2012-07-16T23:59:59.000Z
To effectively understand and treat complex diseases such as cancer, mathematical and statistical modeling is essential if one wants to represent and characterize the interactions among the different regulatory components that govern the underlying...
Vector-Based Dynamic Modeling and Control of the Quattro Parallel Robot by means of Leg Orientations
Paris-Sud XI, Université de
Vector-Based Dynamic Modeling and Control of the Quattro Parallel Robot by means of Leg-speed control of a parallel robot is to define an efficient dynamic model. It is usually not easy to have by a calibrated camera, in the sense of solving the entire control-oriented (hard) modeling problem, both
Tsiotras, Panagiotis
A LuGre Tire Friction Model with Exact Aggregate Dynamics Panagiotis Tsiotras, Efstathios Velenis and Michel Sorine Abstract-- The LuGre dynamic point contact friction model for the two-dimensional translation of a body on a surface has been used in the past to derive a model for the friction forces
Winguth, Arne
a dynamic Earth system model A. Winguth Center for Climatic Research, Department of Atmospheric and Oceanic; accepted 26 October 2005; published 15 December 2005. [1] A complex Earth system model including atmosphere and anthropogenic climate change using a dynamic Earth system model, Geophys. Res. Lett., 32, L23714, doi:10
Steady-State Dynamics of the Forest Fire Model on Complex Networks
Bancal, Jean-Daniel
2009-01-01T23:59:59.000Z
Many sociological networks, as well as biological and technological ones, can be represented in terms of complex networks with a heterogeneous connectivity pattern. Dynamical processes taking place on top of them can be very much influenced by this topological fact. In this paper we consider a paradigmatic model of non-equilibrium dynamics, namely the forest fire model, whose relevance lies in its capacity to represent several epidemic processes in a general parametrization. We study the behavior of this model in complex networks by developing the corresponding heterogeneous mean-field theory and solving it in its steady state. We provide exact and approximate expressions for homogeneous networks and several instances of heterogeneous networks. A comparison of our analytical results with extensive numerical simulations allows to draw the region of the parameter space in which heterogeneous mean-field theory provides an accurate description of the dynamics, and enlights the limits of validity of the mean-field...
Düring, Bertram
2015-01-01T23:59:59.000Z
We propose and investigate different kinetic models for opinion formation, when the opinion formation process depends on an additional independent variable, e.g. a leadership or a spatial variable. More specifically, we consider:(i) opinion dynamics under the effect of opinion leadership, where each individual is characterised not only by its opinion, but also by another independent variable which quantifies leadership qualities; (ii) opinion dynamics modelling political segregation in the `The Big Sort', a phenomenon that US citizens increasingly prefer to live in neighbourhoods with politically like-minded individuals. Based on microscopic opinion consensus dynamics such models lead to inhomogeneous Boltzmann-type equations for the opinion distribution. We derive macroscopic Fokker-Planck-type equations in a quasi-invariant opinion limit and present results of numerical experiments.
. Assigning values to these parameters is a time-dependent process, captured as the evolution of a dynamical categorization task due to the inherent stabilization property of the dynamical formalism. Dynamic Model Coupled-field Dynamic Model · Two coupled dynamic fields, one corresponding to DA, the other to TA, each with activation
Stochastic Wilson-Cowan models of neuronal network dynamics with memory and delay
Goychuk, Igor
2015-01-01T23:59:59.000Z
We consider a simple Markovian class of the stochastic Wilson-Cowan type models of neuronal network dynamics, which incorporates stochastic delay caused by the existence of a refractory period of neurons. From the point of view of the dynamics of the individual elements, we are dealing with a network of non-Markovian stochastic two-state oscillators with memory which are coupled globally in a mean-field fashion. This interrelation of a higher-dimensional Markovian and lower-dimensional non-Markovian dynamics is discussed in its relevance to the general problem of the network dynamics of complex elements possessing memory. The simplest model of this class is provided by a three-state Markovian neuron with one refractory state, which causes firing delay with an exponentially decaying memory within the two-state reduced model. This basic model is used to study critical avalanche dynamics (the noise sustained criticality) in a balanced feedforward network consisting of the excitatory and inhibitory neurons. Such ...
A Dynamic Solar Core Model: On the Activity-Related Changes of the Neutrino Fluxes
Attila Grandpierre
1998-10-08T23:59:59.000Z
The energy sources of the Sun may actually involve a thermonuclear runaway energy source present in stellar energy producing regions. I consider the conjectures of the derived model for the solar neutrino fluxes in case of a solar core allowed to vary in relation to the surface activity cycle. The observed neutrino flux data suggest a solar core possibly varying in time. In the dynamic solar model the quiet and runaway energy sources together may produce quasi-constant flux in the SuperKamiokande because it is sensitive to neutral currents, axions and anti-neutrinos, too. I calculate the contributions of the runaway source to the individual neutrino detectors. The results of the dynamic solar core model suggest that since the HOMESTAKE detects mostly the high energy electron neutrinos, therefore the HOMESTAKE data may aniticorrelate with the activity cycle. Activity correlated changes are expected to be present only marginally in the GALLEX and GNO data. The gallium detectors are sensitive mostly to the pp neutrinos, and the changes of the pp neutrinos arising from the SSM-like core is mostly compensated by the high-energy electron neutrinos produced by the hot bubbles of the dynamic energy source. The results suggest that the GALLEX data may show an anti-correlation, while the SuperKamiokande data may show a correlation with the activity cycle. Predictions of the dynamic solar model are presented for the SNO and Borexino experiments which can distinguish between the effects of the MSW mechanism and the consequences of the dynamic solar model. The results of the dynamic solar model are consistent with the present heioseismic measurements and can be checked with future heioseismic measurements as well. Keywords: solar neutrino problems - solar activity - thermonuclear runaways
Boutchko, R.
2014-01-01T23:59:59.000Z
emission tomography systems and computational fluid dynamicsa computational ?uid dynamics (CFD) model of the systemthe computational domain. A Cartesian coordinate system was
Levitt, Michael
Calibration and Testing of a Water Model for Simulation of the Molecular Dynamics of Proteins important in biological macromolecules, where fewer experimental results are available for calibration. Our
LHC limits on the top-Higgs in models with strong top-quark dynamics
Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Theoretical Physics Department, Fermilab, Batavia, Illinois 60510 (United States)
2011-11-01T23:59:59.000Z
LHC searches for the standard model Higgs boson in WW or ZZ decay modes place strong constraints on the top-Higgs state predicted in many models with new dynamics preferentially affecting top quarks. Such a state couples strongly to top quarks, and is therefore produced through gluon fusion at a rate enhanced relative to the rate for the standard model Higgs boson. A top-Higgs state with mass less than 300 GeV is excluded at 95% C.L. if the associated top-pion has a mass of 150 GeV, and the constraint is even stronger if the mass of the top-pion state exceeds the top-quark mass or if the top-pion decay constant is a substantial fraction of the weak scale. These results have significant implications for theories with strong top dynamics, such as topcolor-assisted technicolor, top-seesaw models, and certain Higgsless models.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-01-01T23:59:59.000Z
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
Alternating-phase focusing: A model to study nonlinear dynamics
Sagalovsky, L.; Delayen, J.R.
1992-09-01T23:59:59.000Z
We discuss a new model to study alternating-phase focusing (APF). Our approach is based on representing the accelerating electric field with a continuous phase modulated traveling wave. The resulting nonlinear equations of motion can be solved analytically to predict the regions of stable APF motion. We also identify the key parameters which adequately describe the physics of APF. The model is believed to be applicable to low-{beta} ion linacs with short independently-controlled superconducting cavities being developed at ANL.
UPDATE ON SMALL MODULAR REACTORS DYNAMIC SYSTEM MODELING TOOL Molten Salt Cooled Architecture
Hale, Richard Edward [ORNL; Cetiner, Sacit M [ORNL; Fugate, David L [ORNL; Qualls, A L [ORNL; Borum, Robert C [ORNL; Chaleff, Ethan S [ORNL; Rogerson, Doug W [ORNL; Batteh, John J [Modelon Corporation; Tiller, Michael M. [Xogeny Corporation
2014-08-01T23:59:59.000Z
The Small Modular Reactor (SMR) Dynamic System Modeling Tool project is in the third year of development. The project is designed to support collaborative modeling and study of various advanced SMR (non-light water cooled) concepts, including the use of multiple coupled reactors at a single site. The objective of the project is to provide a common simulation environment and baseline modeling resources to facilitate rapid development of dynamic advanced reactor SMR models, ensure consistency among research products within the Instrumentation, Controls, and Human-Machine Interface (ICHMI) technical area, and leverage cross-cutting capabilities while minimizing duplication of effort. The combined simulation environment and suite of models are identified as the Modular Dynamic SIMulation (MoDSIM) tool. The critical elements of this effort include (1) defining a standardized, common simulation environment that can be applied throughout the program, (2) developing a library of baseline component modules that can be assembled into full plant models using existing geometry and thermal-hydraulic data, (3) defining modeling conventions for interconnecting component models, and (4) establishing user interfaces and support tools to facilitate simulation development (i.e., configuration and parameterization), execution, and results display and capture.
Using Simulations and kinetic network models to reveal the dynamics and functions of Riboswitches
Jong-Chin Lin; Jeseong Yoon; Changbong Hyeon; D. Thirumalai
2014-10-02T23:59:59.000Z
Riboswitches, RNA elements found in the untranslated region, regulate gene expression by binding to target metaboloites with exquisite specificity. Binding of metabolites to the conserved aptamer domain allosterically alters the conformation in the downstream expression platform. The fate of gene expression is determined by the changes in the downstream RNA sequence. As the metabolite-dependent cotranscriptional folding and unfolding dynamics of riboswitches is the key determinant of gene expression, it is important to investigate both the thermodynamics and kinetics of riboswitches both in the presence and absence of metabolite. Single molecule force experiments that decipher the free energy landscape of riboswitches from their mechanical responses, theoretical and computational studies have recently shed light on the distinct mechanism of folding dynamics in different classes of riboswitches. Here we first discuss the dynamics of water around riboswitch, highlighting that water dynamics can enhance the fluctuation of nucleic acid structure. To go beyond native state fluctuations we used the Self-Organized Polymer (SOP) model to predict the dynamics of add adenine riboswitch under mechanical forces. In addition to quantitatively predicting the folding landscape of add-riboswitch our simulations also explain the difference in the dynamics between pbuE adenine- and add adenine-riboswitches. In order to probe the function {\\it in vivo} we use the folding landscape to propose a system level kinetic network model to quantitatively predict how gene expression is regulated for riboswitches that are under kinetic control.
Dynamic Delayed Duplicate Detection for External Memory Model Checking
Evangelista, Sami
is a method to prove that finite state systems match their spec- ification. Given a model of the system space, of the system to check the validity of the property. Despite its simplicity, its practical to benefit from the aggregate computational power and memory of a cluster of machines, or make use
Computational Fluid Dynamics Modeling of the John Day Dam Tailrace
Rakowski, Cynthia L.; Perkins, William A.; Richmond, Marshall C.; Serkowski, John A.
2010-07-08T23:59:59.000Z
US Army Corps of Engineers - Portland District required that a two-dimensional (2D) depth-averaged and a three-dimensional (3D) free-surface numerical models to be developed and validated for the John Day tailrace. These models were used to assess potential impact of a select group of structural and operational alternatives to tailrace flows aimed at improving fish survival at John Day Dam. The 2D model was used for the initial assessment of the alternatives in conjunction with a reduced-scale physical model of the John Day Project. A finer resolution 3D model was used to more accurately model the details of flow in the stilling basin and near-project tailrace hydraulics. Three-dimensional model results were used as input to the Pacific Northwest National Laboratory particle tracking software, and particle paths and times to pass a downstream cross section were used to assess the relative differences in travel times resulting from project operations and structural scenarios for multiple total river flows. Streamlines and neutrally-buoyant particles were seeded in all turbine and spill bays with flows. For a Total River of 250 kcfs running with the Fish Passage Plan spill pattern and a spillwall, the mean residence times for all particles were little changed; however the tails of the distribution were truncated for both spillway and powerhouse release points, and, for the powerhouse releases, reduced the residence time for 75% of the particles to pass a downstream cross section from 45.5 minutes to 41.3 minutes. For a total river of 125 kcfs configured with the operations from the Fish Passage Plan for the temporary spillway weirs and for a proposed spillwall, the neutrally-buoyant particle tracking data showed that the river with a spillwall in place had the overall mean residence time increase; however, the residence time for 75% of the powerhouse-released particles to pass a downstream cross section was reduced from 102.4 min to 89 minutes.
Li, Tim
Dynamic and Thermodynamic AirSea Coupling Associated with the Indian Ocean Dipole Diagnosed from and the thermodynamic airsea coupling in shaping the different model behaviors. The Bjerknes feedback processes include of the dynamic and ther- modynamic feedback processes. The distinctive features in the dynamic and thermodynamic
Multiple higher-order singularities and iso-dynamics in a simple glass-former model
Nicoletta Gnan; Gayatri Das; Matthias Sperl; Francesco Sciortino; Emanuela Zaccarelli
2014-07-15T23:59:59.000Z
We investigate the slow dynamics of a colloidal model with two repulsive length scales, whose interaction potential is the sum of a hard-core and a square shoulder. Despite the simplicity of the interactions, Mode-Coupling theory predicts a complex dynamic scenario: a fluid-glass line with two reentrances and a glass-glass line ending with multiple higher-order ($A_3$ or $A_4$) singularities. In this work we verify the existence of the two $A_4$ points by numerical simulations, observing subdiffusive behaviour of the mean-square displacement and logarithmic decay of the density correlators. Surprisingly, we also discover a novel dynamic behaviour generated by the competition between the two higher-order singularities. This results in the presence of special loci along which the dynamics is identical \\textit{at all} length and time scales.
Modeling ramp compression experiments using large-scale molecular dynamics simulation.
Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)
2011-10-01T23:59:59.000Z
Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.
Modelling the Structure and Dynamics of Science Using Books
Ginda, Michael; Borner, Katy
2015-01-01T23:59:59.000Z
Scientific research is a major driving force in a knowledge based economy. Income, health and wellbeing depend on scientific progress. The better we understand the inner workings of the scientific enterprise, the better we can prompt, manage, steer, and utilize scientific progress. Diverse indicators and approaches exist to evaluate and monitor research activities, from calculating the reputation of a researcher, institution, or country to analyzing and visualizing global brain circulation. However, there are very few predictive models of science that are used by key decision makers in academia, industry, or government interested to improve the quality and impact of scholarly efforts. We present a novel 'bibliographic bibliometric' analysis which we apply to a large collection of books relevant for the modelling of science. We explain the data collection together with the results of the data analyses and visualizations. In the final section we discuss how the analysis of books that describe different modellin...
Glinsky, M.E.; Amendt, P.A.; Bailey, D.S.; London, R.A.; Rubenchik, A.M. [Lawrence Livermore National Lab., CA (United States); Strauss, M. [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev
1997-03-04T23:59:59.000Z
The validity of an extended Rayleigh model for laser generated bubbles in soft tissue is examined. This model includes surface tension, viscosity, a realistic water equation of state, material strength and failure, stress wave emission, and linear growth of interface instabilities. It is compared to dynamic simulations using LATIS, which include stress wave propagation, water equation of state, material strength and failure, and viscosity. The model and the simulations are compared using 1-D spherical geometry with bubble in center and a 2-D cylindrical geometry of a laser fiber in water with a bubble formed at the end of the fiber. The model executes over 300x faster on computer than the dynamic simulations.
Power Flow Modelling of Dynamic Systems - Introduction to Modern Teaching Tools
Geitner, Gert-Helge
2015-01-01T23:59:59.000Z
As tools for dynamic system modelling both conventional methods such as transfer function or state space representation and modern power flow based methods are available. The latter methods do not depend on energy domain, are able to preserve physical system structures, visualize power conversion or coupling or split, identify power losses or storage, run on conventional software and emphasize the relevance of energy as basic principle of known physical domains. Nevertheless common control structures as well as analysis and design tools may still be applied. Furthermore the generalization of power flow methods as pseudo-power flow provides with a universal tool for any dynamic modelling. The phenomenon of power flow constitutes an up to date education methodology. Thus the paper summarizes fundamentals of selected power flow oriented modelling methods, presents a Bond Graph block library for teaching power oriented modelling as compact menu-driven freeware, introduces selected examples and discusses special f...
Effects of CDTT model on the dynamical instability of cylindrically symmetric collapsing stars
Kausar, Hafiza Rizwana, E-mail: rizwa_math@yahoo.com [Centre for Applicable Mathematics and Statistics, UCP Business School, University of Central Punjab, Johar Town, Lahore (Pakistan)
2013-01-01T23:59:59.000Z
We assume cylindrically symmetric stars which begin collapsing by dissipating energy in the form of heat flux. We wish to study the effects of Carroll-Duvvuri-Trodden-Turner (CDTT) model, f(R) = R+??{sup 4}/R, on the range of dynamical instability. For this purpose, perturbation scheme is applied to all the metric functions, material functions and f(R) model to obtain the full set of dynamical equation which control the evolution of the physical variables at the surface of a star. It is found that instability limit involves adiabatic index ? which depends on the density profile and immense terms of perturbed CDTT model. In addition, model is constrained by some requirement, e.g. positivity of physical quantities. We also reduce our results asymptotically as ??0, being the GR results in both the Newtonian and post Newtonian regimes.
Dynamics of Cell Shape and Forces on Micropatterned Substrates Predicted by a Cellular Potts Model
Philipp J. Albert; Ulrich S. Schwarz
2014-05-19T23:59:59.000Z
Micropatterned substrates are often used to standardize cell experiments and to quantitatively study the relation between cell shape and function. Moreover, they are increasingly used in combination with traction force microscopy on soft elastic substrates. To predict the dynamics and steady states of cell shape and forces without any a priori knowledge of how the cell will spread on a given micropattern, here we extend earlier formulations of the two-dimensional cellular Potts model. The third dimension is treated as an area reservoir for spreading. To account for local contour reinforcement by peripheral bundles, we augment the cellular Potts model by elements of the tension-elasticity model. We first parameterize our model and show that it accounts for momentum conservation. We then demonstrate that it is in good agreement with experimental data for shape, spreading dynamics, and traction force patterns of cells on micropatterned substrates. We finally predict shapes and forces for micropatterns that have not yet been experimentally studied.
Detonating Failed Deflagration Model of Thermonuclear Supernovae I. Explosion Dynamics
Tomasz Plewa
2006-11-24T23:59:59.000Z
We present a detonating failed deflagration model of Type Ia supernovae. In this model, the thermonuclear explosion of a massive white dwarf follows an off-center deflagration. We conduct a survey of asymmetric ignition configurations initiated at various distances from the stellar center. In all cases studied, we find that only a small amount of stellar fuel is consumed during deflagration phase, no explosion is obtained, and the released energy is mostly wasted on expanding the progenitor. Products of the failed deflagration quickly reach the stellar surface, polluting and strongly disturbing it. These disturbances eventually evolve into small and isolated shock-dominated regions which are rich in fuel. We consider these regions as seeds capable of forming self-sustained detonations that, ultimately, result in the thermonuclear supernova explosion. Preliminary nucleosynthesis results indicate the model supernova ejecta are typically composed of about 0.1-0.25 Msun of silicon group elements, 0.9-1.2 Msun of iron group elements, and are essentially carbon-free. The ejecta have a composite morphology, are chemically stratified, and display a modest amount of intrinsic asymmetry. The innermost layers are slightly egg-shaped with the axis ratio ~1.2-1.3 and dominated by the products of silicon burning. This central region is surrounded by a shell of silicon-group elements. The outermost layers of ejecta are highly inhomogeneous and contain products of incomplete oxygen burning with only small admixture of unburned stellar material. The explosion energies are ~1.3-1.5 10^51 erg.
Bass, Steffen A.
-ion collisions? · Introduction: the basics of kinetic theory · Examples of transport models and their application-equilibrium QGP and hydrodynamic expansion hadronization hadronic phase and freeze-out · rigorous calculation and data Transport-Theory: · only observe the final state · rely on QGP signatures predicted by Theory
Combining Multiple Dynamic Models and Deep Learning Architectures for Tracking the
Carneiro, Gustavo
1 Combining Multiple Dynamic Models and Deep Learning Architectures for Tracking the Left Ventricle such that the expected segmentation of the current time step is estimated based on the appearance, shape, and motion Classifiers. This work was supported by project the FCT (ISR/IST plurianual funding) through the PIDDAC
Modeling and Dynamic Management of 3D Multicore Systems with Liquid Cooling
Simunic, Tajana
Modeling and Dynamic Management of 3D Multicore Systems with Liquid Cooling Ayse K. Coskun , Jos liquid cooling. Furthermore, for systems capable of varying the coolant flow rate at runtime, our University of Madrid, Spain. Embedded Systems Laboratory (ESL), Ecole Polytechnique FÂ´edÂ´erale de Lausanne
A model of sediment resuspension and transport dynamics in southern Lake Michigan
A model of sediment resuspension and transport dynamics in southern Lake Michigan Jing Lou and David J. Schwab NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan Dmitry Beletsky1 Department of Naval Architecture and Marine Engineering, University of Michigan, Ann Arbor Nathan Hawley NOAA
Simplified dynamic models for control of riser slugging in offshore oil production
Skogestad, Sigurd
ForReview Only Simplified dynamic models for control of riser slugging in offshore oil production Journal: Oil and Gas Facilities Manuscript ID: Draft Manuscript Type: Technical Paper Date Submitted, Department of Chemical Engineering Keywords: oil production, two-phase flow, severe slugging, riser slugging
A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids
Hayat, Majeed M.
systems. The control system of a reliable power grid requires (1) a good understanding of the current in the control/communication systems) factors can affect cascading failures in power grids. These factors can1 A Probabilistic Model for the Dynamics of Cascading Failures and Blackouts in Power Grids Mahshid
Modeling Red Blood Cell and Iron Dynamics in Patients Undergoing Periodic EPO and Iron Treatments
Modeling Red Blood Cell and Iron Dynamics in Patients Undergoing Periodic EPO and Iron Treatments H in the kidneys, that stimulates red blood cell (RBC) production. Without intervention, patients suffer from, erythrocyte, red blood cell, chronic kidney disease, dialysis, iron, neocytolysis, hepcidin, EPO, hemoglobin e
DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT
Paris-Sud XI, Université de
1 DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT CHAMOUN MARWAN to improve industrial energy efficiency, the development of a high temperature heat pump using water vapor as refrigerant is investigated. Technical problems restraining the feasibility of this industrial heat pump
Coastal Dynamics 2013 MODELING OF THE TOHOKU-OKI 2011 TSUNAMI GENERATION, FAR-FIELD AND
Kirby, James T.
Coastal Dynamics 2013 Paper No. MODELING OF THE TOHOKU-OKI 2011 TSUNAMI GENERATION, FAR Tsunami hazard assessment for future megathrust earthquakes requires that we understand the source mechanisms and tsunami generation processes for large historical events, such as the devastating Tohoku
Modeling and Validation of Fuel Cell Water Dynamics using Neutron Imaging
Stefanopoulou, Anna
the gas diffusion layer and flow channels of an operating polymer electrolyte membrane fuel cell (PEMFC. However, polymer electrolyte membrane fuel cells (PEMFCs) operate below the boiling point of water causingModeling and Validation of Fuel Cell Water Dynamics using Neutron Imaging Jason B. Siegel, Denise A
Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model
Paris-Sud XI, Université de
of biomedical signal processing. Specifically, the extraction of ECG signals from low SNR measurementsFiltering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model University of Technology, Tehran, Iran 2 Images and Signals Laboratory, Institut National Polytechnique de
Modelling Shale Gas Flow Using the Concept of Dynamic Apparent Permeability
Farid, Syed Munib Ullah
2015-05-12T23:59:59.000Z
The basic idea behind this research is to propose a work flow to model gas flow in numerical simulators, which would take into consideration all the complexities of the multiple porosity systems that exist in shale matrix and the different dynamics...
Physics-Based Low Order Galerkin Models in Fluid Dynamics & Flow Control
Gorban, Alexander N.
(Berlin Institute of Technology MB1, Germany) Marek Morzynski (Poznan University of Technology, Poland models of energy supply and consumption. Yet a third principle is the realization that governing flow to time-averaged energy dynamics of Galerkin modes, and gives rise to physically based, nonlinear sub
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness
O'Leary, Michael
A Diffusion Model in Population Genetics with Mutation and Dynamic Fitness Mike O'Leary Department of Mathematics Towson University World Conference on Nonlinear Analysis Orlando, FL July 2008 Mike O'Leary of this work are joint with Judith Miller, Georgetown University. Mike O'Leary (Towson University) A Diffusion
Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales
Ben-Zion, Yehuda
Quasi-static and Quasi-dynamic Modeling of Earthquake Failure at Intermediate Scales GERT ZO¨ LLER1 of the regions around the fault, static/ kinetic friction laws with possible gradual healing, and stress transfer based on the solution of CHINNERY (1963) for static dislocations in an elastic half-space. As a new
Simplified dynamic models for control of riser slugging in offshore oil production
Skogestad, Sigurd
ForReview Only Simplified dynamic models for control of riser slugging in offshore oil production, Department of Chemical Engineering Keywords: oil production, two-phase flow, severe slugging, riser slugging for control of riser slugging in offshore oil production Esmaeil Jahanshahi, Sigurd Skogestad Department
EXPERIMENTAL VALIDATION OF A DYNAMIC MODEL FOR A MONO-TUBE CAVITY RECEIVER
dish is the heat source for a mono-tube steam cavity receiver that generates superheated steam at 500, Australia Keywords: solar-thermal, direct steam generation, moving-boundary formulation, ANU Abstract This paper describes a dynamic model of a steam cavity receiver and presents results from simulations
Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model
Boyer, Edmond
Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model Geoffroy J isotherms of 4He in a silica aerogel be- come discontinuous below a critical temperature. We show by the aerogel structure, but to the disorder-driven critical point predicted for the athermal out
Adaptive Model Predictive Control of the Hybrid Dynamics of a Fuel Cell System.
Paris-Sud XI, Université de
Adaptive Model Predictive Control of the Hybrid Dynamics of a Fuel Cell System. M. Fiacchini, T operation of a fuel cell system is presented. The aim of the control design is to guarantee that the oxygen control to a fuel cell plant is presented. The fuel cell, located in the laboratory of the Department
Energy-Aware Modeling and Scheduling of Real-Time Tasks for Dynamic Voltage Scaling
Xu, Cheng-Zhong
scaling (DVS) is an effective approach to power reduction by scaling the processor voltage and frequency the voltage accordingly. On the other hand, a reduction of the operating frequency leads to an increaseEnergy-Aware Modeling and Scheduling of Real-Time Tasks for Dynamic Voltage Scaling Xiliang Zhong
Inferred Models for Dynamic and Sparse Hardware-Software Spaces Weidan Wu Benjamin C. Lee
Lee, Benjamin C.
Inferred Models for Dynamic and Sparse Hardware-Software Spaces Weidan Wu Benjamin C. Lee Duke University {weidan.wu, benjamin.c.lee}@duke.edu Abstract Diverse software and heterogeneous hardware pose new hardware-software analysis. These strategies include (i) identifying shared software behavior; (ii
A MODEL FOR EXPERIMENTALLY-OBSERVED HIGH-STRAIN-RATE DYNAMIC STRAIN AGING IN TITANIUM
Nemat-Nasser, Sia
A MODEL FOR EXPERIMENTALLY-OBSERVED HIGH- STRAIN-RATE DYNAMIC STRAIN AGING IN TITANIUM JINGYI CHENG an anomalous response by commercially pure titanium at relatively high temperatures: for a ®xed high strain seems to accurately predict the response of commercially pure titanium, over a broad range of strain
Modeling Sediment and Wood Storage and Dynamics in Small Mountainous Watersheds
85 Modeling Sediment and Wood Storage and Dynamics in Small Mountainous Watersheds Stephen T controls on supply and transport of sediment and wood in a small (approximately two square kilometers) basin in the Oregon Coast Range, typical of streams at the interface between episodic sediment and wood
Simulation of exhaust gas pollution within an eventdriven multimodal dynamic traffic model
Toint, Philippe
pollution caused by urban vehicles (cars and busses), a major source of urban environment deterioration1 Simulation of exhaust gas pollution within an eventdriven multimodal dynamic traffic model E concerns. Among the drawbacks of urban life, one often mentions the level of pollution, mostly resulting
Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky
Polymer dynamics in repton model at large fields Anatoly B. Kolomeisky Department of Chemistry, Rice University, Houston, Texas 77005-1892 Andrzej Drzewin´ski Czestochowa University of Technology, Institute of Mathematics and Computer Science, ul.Dabrowskiego 73, 42-200 Czestochowa, Poland and Institute
Longitudinal study of herpes simplex virus type 2 infection using viral dynamic modelling
Blower, Sally
HSV Longitudinal study of herpes simplex virus type 2 infection using viral dynamic modelling of herpes simplex virus type 2 (HSV-2) change over time and these changes affect transmission and clinical infection that cannot be obtained by other methods. H erpes simplex virus type 2 (HSV-2), the primary cause
MODELING AND ANALYSIS OF THE DYNAMICS OF DRY-FRICTION-DAMPED STRUCTURAL SYSTEMS
Paris-Sud XI, Université de
MODELING AND ANALYSIS OF THE DYNAMICS OF DRY-FRICTION-DAMPED STRUCTURAL SYSTEMS by Olivier J . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.1 Nonlinear methods for the analysis of friction-damped systems . . . . . . . . . . . . . . . . . . . . . . . . 15 II. HYBRID FREQUENCY-TIME DOMAIN METHODS FOR THE ANALYSIS OF COMPLEX STRUCTURAL SYSTEMS WITH DRY
FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY
Daripa, Prabir
FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY Prabir Daripa developed flows in enhanced oil recovery (EOR). In a recent exhaustive study [Transport in Porous Media, 93 fluid flows that occur in porous media during tertiary dis- placement process of chemical enhanced oil
Dynamic model failure tests of dam structures Dalian University of Technology, Dalian 116024, China
Spencer Jr., Billie F.
Dynamic model failure tests of dam structures Gao Lin Dalian University of Technology, Dalian carried out in Dalian University of Technology, China. The relevant research work is briefly introduced on a earthquake simulating shaking table installed in the Dalian University of Technology. The relevant research
Perovskite Quantum Dots Modeled Using ab Initio and Replica Exchange Molecular Dynamics
Sargent, Edward H. "Ted"
Perovskite Quantum Dots Modeled Using ab Initio and Replica Exchange Molecular Dynamics Andrei Buin halide perovskites have recently attracted tremen- dous attention at both the experimental. Here we investigate perovskite quantum dots from theory, predicting an upper bound of the Bohr radius
DATA COLLECTION FOR DEVELOPING A DYNAMIC MODEL OF A LIGHT HELICOPTER
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 procedure and a reliable measurement setup for the collection of the flight test data. The latter
Gotika, Priyanka
2012-02-14T23:59:59.000Z
-SMOOTH DYNAMICAL SYSTEMS : : : : : : : : : : : : : : : : : : : : : 7 A. Classical simple harmonic oscillator . . . . . . . . . . . . . 7 B. Spring-mass-dash-pot systems . . . . . . . . . . . . . . . . 7 C. Coulomb friction model... . . . . . . . . . 22 B. Lumped parameter system with a Bingham-type dash- pot of non-linear monotonic characteristics . . . . . . . . . 24 C. Lumped parameter system with a Bingham-type dash- pot of non-linear non-monotonic characteristics . . . . . . 27 D. Lumped...
A model problem for unsaturated groundwater ow with dynamic capillary pressure
Hulshof, Joost
] as a model equation for Darcy ow in porous media with a dynamic capillary pressure relation, the general pressure leads to a nonlinear di#11;usion-convection equation extended with a nonlinear third order term equation is the Burgers' equation and the third order term is linear. We investigate stability
A Dynamic Network Economic Model of a Service-Oriented Internet with Price and
Nagurney, Anna
Nagurney Department of Operations and Information Management, Isenberg School of Management, Uni- versity-mail: dongl@som.umass.edu Sara Saberi Department of Operations and Information Management, Isenberg SchoolA Dynamic Network Economic Model of a Service-Oriented Internet with Price and Quality Competition
Sukhatme, Gaurav S.
Helicopter Srikanth Saripalli and Gaurav S. Sukhatme Robotics Embedded Systems Laboratory Department,gaurav}@robotics.usc.edu Abstract We propose the use of a model helicopter to emulate the landing dynamics of a spacecraft. Our controller accepts thruster inputs (like those on a spacecraft) and converts them into appropriate helicopter
Modelling dynamics of piezoelectric solids in the two-dimensional case
Melnik, Roderick
that may not be attained by purely electronic means. These new horizons of piezoelectric applicationsModelling dynamics of piezoelectric solids in the two-dimensional case R.V.N. Melnik a,*, K; Hollow piezoceramic cylinders; Corner points; Accuracy estimates 1. Introduction In many applications
A Kernel-Based Spatio-Temporal Dynamical Model for Nowcasting Weather Radar Reflectivities
A Kernel-Based Spatio-Temporal Dynamical Model for Nowcasting Weather Radar Reflectivities Ke Xu of the technique and its potential for nowcasting weather radar reflectivities. Key Words: Bayesian, dilation to nowcasting weather radar reflectivities into two general categories. The first is the use of simple
Melnik, Roderick
Modeling the essential atomistic influence in the phase transformation dynamics of shape memory of multivariant phase transformation in shape memory alloy has been developed. This paper is focused on linking Shape memory effects in alloys are observed due to the existence of large differences in the variants
Experimental and constitutive modeling of a filled rubber with emphasis on the dynamical properties
Paris-Sud XI, Université de
Experimental and constitutive modeling of a filled rubber with emphasis on the dynamical properties, the elas- tomeric material can be filler-reinforced synthetic rubber or natural rubber. In normal flight to 70o C). Here, characterization tests carried out on a carbon-black filled butadiene rubber
Steady-State and Dynamic Modeling of Commercial Slurry High-Density Polyethylene (HDPE) Processes
Liu, Y. A.
, solvent, and oligomeric species from the polymer. Sol- vent is separated from the oligomer and recycled, Polymers Plus and Aspen Dynamics. The discussion includes thermodynamic properties, phase equilibrium, reaction kinetics, polymer properties, and other modeling issues. We characterize a Ziegler- Natta catalyst
Modelling dynamics of samples exposed to free-electron-laser radiation with Boltzmann equations
Beata Ziaja; Antonio R. B. de Castro; Edgar Weckert; Thomas Moeller
2005-12-20T23:59:59.000Z
We apply Boltzmann equations for modelling the radiation damage in samples irradiated by photons from free electron laser (FEL). We test this method in a study case of a spherically symmetric xenon cluster irradiated with VUV FEL photons. The results obtained demonstrate the potential of the Boltzmann method for describing the complex and non-equilibrium dynamics of samples exposed to FEL radiation.
A Dynamical Systems Analysis of the Data Assimilation Linked Ecosystem Carbon (DALEC) Models
Skeldon, Anne C.
A Dynamical Systems Analysis of the Data Assimilation Linked Ecosystem Carbon (DALEC) Models Anna M make it ever more important to understand the processes involved in Earth systems, such as the carbon with it the ability to perform ever- more detailed studies of the Earth system and its components. Such studies help
Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region
T.-S. H. Lee; A. Matsuyama; T. Sato
2006-11-15T23:59:59.000Z
A dynamical coupled-channel model is presented for investigating the nucleon resonances (N*) in the meson production reactions induced by pions and photons. Our objective is to extract the N* parameters and to investigate the meson production reaction mechanisms for mapping out the quark-gluon substructure of N* from the data. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method.
Wegner, T.
We evaluate the simulation of polar stratospheric clouds (PSCs) in the Specified Dynamics version of the Whole Atmosphere Community Climate Model for the Antarctic winter 2005. In this model, PSCs are assumed to form ...
Schuh, Harald
with a dynamic Earth system model (completed in October 2004) Variations of Earth rotation are caused Earth system model DyMEG has been developed. It is based on the balance of angular momentum
Real-Time Multi-Sensor Multi-Source Network Data Fusion Using Dynamic Traffic Assignment Models
Ben-Akiva, Moshe E.
This paper presents a model-based data fusion framework that allows systematic fusing of multi-sensor multi-source traffic network data at real-time. Using simulation-based Dynamic Traffic Assignment (DTA) models, the ...
Nonparametric estimation of varying coefficient dynamic panel models
Cai, Zongwu; Li, Qi
2008-10-01T23:59:59.000Z
#2; m2 because the number of parameters in ~6! is m2+ However, when m1 #7; m2, the model is overidentified, and there may not exist a unique a to satisfy ~6!+ To obtain a unique a satisfy- ing ~6!, we premultiply ~6! by an m2 #3; m1 matrix Sn' , where... with Qit #1; Q~Vit ! and n #1; NT, Sn #1; 1 n #6; i#1;1 N #6; t#1;1 T QitUit' Kh~Zit #5; z!+ Then solving for a we obtain [a #1; ~Sn' Sn !#5;1Sn' Tn , (7) where Tn #1; 1 n #6; i#1;1 N #6; t#1;1 T Qit Kh~Zit #5; z!Yit + The estimator [a defined in ~7...
Monte Carlo study of the CO-poisoning dynamics in a model for the catalytic oxidation of CO
Marro, Joaquín
Monte Carlo study of the CO-poisoning dynamics in a model for the catalytic oxidation of CO The poisoning dynamics of the ZiffGulariBarshad Phys. Rev. Lett. 56, 2553 1986 model, for a monomer absorbing state and close to the coexistence point. Analysis of the average poisoning time ( p) allows us
DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS
X. Wang; X. Sun; H. Zhao
2011-09-01T23:59:59.000Z
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.
Yu. S. Aidarova; S. P. Kuznetsov
2010-01-19T23:59:59.000Z
We study numerically chaotic behavior associated with a hyperbolic strange attractor of Plykin type in the model of Hunt, an artificially constructed dynamical system with continuous time. There are presented portraits of the attractor, plots of realizations for chaotic signal generated by the system, illustrations of the sensitive dependence on initial conditions for the trajectories on the attractor. Quantitative characteristics of the attractor are estimated, including the Lyapunov exponents and the attractor dimension. We discuss symbolic dynamics on the attractor, find out and analyze some unstable periodic orbit belonging to the attractor.
On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhang, S.; Wang, M.; Ghan, S. J.; Ding, A.; Wang, H.; Zhang, K.; Neubauer, D.; Lohmann, U.; Ferrachat, S.; Takeamura, T.; et al
2015-09-02T23:59:59.000Z
Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (?500), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascendmore »(?500 ?1) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is as large as that in stratocumulus regimes, which indicates that regimes with strong large-scale ascend are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm d?1) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes than that globally, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.« less
Static and Dynamic Modeling of a Solar Active Region. I: Soft X-Ray Emission
Harry P. Warren; Amy R. Winebarger
2006-09-01T23:59:59.000Z
Recent simulations of solar active regions have shown that it is possible to reproduce both the total intensity and the general morphology of the high temperature emission observed at soft X-ray wavelengths using static heating models. There is ample observational evidence, however, that the solar corona is highly variable, indicating a significant role for dynamical processes in coronal heating. Because they are computationally demanding, full hydrodynamic simulations of solar active regions have not been considered previously. In this paper we make first application of an impulsive heating model to the simulation of an entire active region, AR8156 observed on 1998 February 16. We model this region by coupling potential field extrapolations to full solutions of the time-dependent hydrodynamic loop equations. To make the problem more tractable we begin with a static heating model that reproduces the emission observed in 4 different \\textit{Yohkoh} Soft X-Ray Telescope (SXT) filters and consider dynamical heating scenarios that yield time-averaged SXT intensities that are consistent with the static case. We find that it is possible to reproduce the total observed soft X-ray emission in all of the SXT filters with a dynamical heating model, indicating that nanoflare heating is consistent with the observational properties of the high temperature solar corona.
A Dynamic Feedback Model for High Repetition Rate LINAC-Driven FELS
Mellado Munoz, M.; Doolittle, L.; Emma, P.; Huang, G.; Ratti, A.; Serrano, C.; Byrd, J. M.
2012-05-20T23:59:59.000Z
One of the concepts for the next generation of linacdriven FELs is a CW superconducting linac driving an electron beam with MHz repetition rates. One of the challenges for next generation FELs is improve the stability of the xray pulses by improving the shot-to-shot stability of the energy, charge, peak current, and timing jitter of the electron beam. A high repetition rate FEL with a CW linac presents an opportunity to use a variety of broadband feedbacks to stabilize the beam parameters. To understand the performance of such a feedback system, we are developing a dynamic model of the machine with a focus on the longitudinal beam properties. The model is being developed as an extension of the LITrack code and includes the dynamics of the beam-cavity interaction, RF feedback, beam-based feedback, and multibunch effects. In this paper, we present a detailed description of this model.
Patrick B. Warren; Andrey Vlasov
2014-02-25T23:59:59.000Z
We extend our previous study [J. Chem. Phys. 138, 204907 (2013)] to quantify the screening properties of four mesoscale smoothed charge models used in dissipative particle dynamics. Using a combination of the hypernetted chain integral equation closure and the random phase approximation, we identify regions where the models exhibit a real-valued screening length, and the extent to which this agrees with the Debye length in the physical system. We find that the second moment of the smoothed charge distribution is a good predictor of this behaviour. We are thus able to recommend a consistent set of parameters for the models.
Identification of Hybrid Dynamical Models of Human Movement via Switched System Optimal Control
Vasudevan, Ramanarayan
2012-01-01T23:59:59.000Z
of constrained nonlinear switched dynamical systems. Inconstrained nonlinear switched dynamical systems is devised.
Modeling, simulation, and testing of the mechanical dynamics of and RF MEMS switch.
Sumali, Hartono; Epp, David S.; Massad, Jordan Elias; Dyck, Christopher William; Starr, Michael James
2005-07-01T23:59:59.000Z
Mechanical dynamics can be a determining factor for the switching speed of radio-frequency microelectromechanical systems (RF MEMS) switches. This paper presents the simulation of the mechanical motion of a microswitch under actuation. The switch has a plate suspended by springs. When an electrostatic actuation is applied, the plate moves toward the substrate and closes the switch. Simulations are calculated via a high-fidelity finite element model that couples solid dynamics with electrostatic actuation. It incorporates non-linear coupled dynamics and accommodates fabrication variations. Experimental modal analysis gives results in the frequency domain that verifies the natural frequencies and mode shapes predicted by the model. An effective 1D model is created and used to calculate an actuation voltage waveform that minimizes switch velocity at closure. In the experiment, the switch is actuated with this actuation voltage, and the displacements of the switch at various points are measured using a laser Doppler velocimeter through a microscope. The experiments are repeated on several switches from different batches. The experimental results verify the model.
A moist aquaplanet variant of the Held–Suarez test for atmospheric model dynamical cores
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Thatcher, D. R.; Jablonowski, C.
2015-09-29T23:59:59.000Z
A moist idealized test case (MITC) for atmospheric model dynamical cores is presented. The MITC is based on the Held–Suarez (HS) test that was developed for dry simulations on a flat Earth and replaces the full physical parameterization package with a Newtonian temperature relaxation and Rayleigh damping of the low-level winds. This new variant of the HS test includes moisture and thereby sheds light on the non-linear dynamics-physics moisture feedbacks without the complexity of full physics parameterization packages. In particular, it adds simplified moist processes to the HS forcing to model large-scale condensation, boundary layer mixing, and the exchange ofmore »latent and sensible heat between the atmospheric surface and an ocean-covered planet. Using a variety of dynamical cores of NCAR's Community Atmosphere Model (CAM), this paper demonstrates that the inclusion of the moist idealized physics package leads to climatic states that closely resemble aquaplanet simulations with complex physical parameterizations. This establishes that the MITC approach generates reasonable atmospheric circulations and can be used for a broad range of scientific investigations. This paper provides examples of two application areas. First, the test case reveals the characteristics of the physics-dynamics coupling technique and reproduces coupling issues seen in full-physics simulations. In particular, it is shown that sudden adjustments of the prognostic fields due to moist physics tendencies can trigger undesirable large-scale gravity waves, which can be remedied by a more gradual application of the physical forcing. Second, the moist idealized test case can be used to intercompare dynamical cores. These examples demonstrate the versatility of the MITC approach and suggestions are made for further application areas. The new moist variant of the HS test can be considered a test case of intermediate complexity.« less
Isaac, Palathinkal Manu
1994-01-01T23:59:59.000Z
models were evaluated to determine which is more accurate. Statistical tests were conducted on the link volume data to gauge the relative accuracy of the two models. The new nodal capacity restricted dynamic assignment model was validated... LITERATURE REVIEW . . . Traffic Assignment Techniques. . . . . . Link Impedance. . . . . . Existing Traffic Models. Comparison and Validation of Traffic Assignment Summary. . III STUDY DESIGN. . . . . . . . . . . . . . . Study Approach . Network...
A. Prados; J. J. Brey
2001-07-02T23:59:59.000Z
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.
Combining Coarse-Grained Protein Models with Replica-Exchange All-Atom Molecular Dynamics
Wabik, Jacek; Gront, Dominik; Kouza, Maksim; Kolinski, Andrzej
2013-01-01T23:59:59.000Z
We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.
Modeling and control of entanglement dynamics in laser cooling of trapped atoms
Maryam Roghani; Heinz-Peter Breuer; Hanspeter Helm
2011-08-01T23:59:59.000Z
We discuss the dynamical behavior of the entanglement between the internal and the external degrees of freedom of a trapped atom in electromagnetically-induced transparency (EIT) laser cooling. It is shown that essential features of the intricate entanglement dynamics observed in full numerical simulations of the underlying quantum master equation can be understood in terms of a two-state model on the basis of Landau-Zener splittings in the atom-laser field Hamiltonian. An extension of this model to an effective non-Hermitian Hamiltonian is constructed which describes the decay of entanglement by spontaneous emission processes. We also discuss schemes for the control of entanglement and demonstrate that a permanent entanglement can be imprinted on trapped atoms through a rapid switch off of the driving fields. Finally, we point out fundamental distinctions between the entanglement created in EIT cooling and in the cooling scheme based on velocity-selective coherent population trapping.
Control method and system for hydraulic machines employing a dynamic joint motion model
Danko, George (Reno, NV)
2011-11-22T23:59:59.000Z
A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.
Systematic study of 16O-induced fusions with the improved quantum molecular dynamics model
Ning Wang; Kai Zhao; Zhuxia Li
2014-11-12T23:59:59.000Z
The heavy-ion fusion reactions with 16O bombarding on 62Ni, 65Cu, 74Ge, 148Nd, 180Hf, 186W, 208Pb, 238U are systematically investigated with the improved quantum molecular dynamics (ImQMD) model. The fusion cross sections at energies near and above the Coulomb barriers can be reasonably well reproduced by using this semi-classical microscopic transport model with the parameter sets SkP* and IQ3a. The dynamical nucleus-nucleus potentials and the influence of Fermi constraint on the fusion process are also studied simultaneously. In addition to the mean field, the Fermi constraint also plays a key role for the reliable description of fusion process and for improving the stability of fragments in heavy-ion collisions.
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
2015-03-20T23:59:59.000Z
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
A Nonlocal Peridynamic Plasticity Model for the Dynamic Flow and Fracture of Concrete.
Vogler, Tracy; Lammi, Christopher James
2014-10-01T23:59:59.000Z
A nonlocal, ordinary peridynamic constitutive model is formulated to numerically simulate the pressure-dependent flow and fracture of heterogeneous, quasi-brittle ma- terials, such as concrete. Classical mechanics and traditional computational modeling methods do not accurately model the distributed fracture observed within this family of materials. The peridynamic horizon, or range of influence, provides a characteristic length to the continuum and limits localization of fracture. Scaling laws are derived to relate the parameters of peridynamic constitutive model to the parameters of the classical Drucker-Prager plasticity model. Thermodynamic analysis of associated and non-associated plastic flow is performed. An implicit integration algorithm is formu- lated to calculate the accumulated plastic bond extension and force state. The gov- erning equations are linearized and the simulation of the quasi-static compression of a cylinder is compared to the classical theory. A dissipation-based peridynamic bond failure criteria is implemented to model fracture and the splitting of a concrete cylinder is numerically simulated. Finally, calculation of the impact and spallation of a con- crete structure is performed to assess the suitability of the material and failure models for simulating concrete during dynamic loadings. The peridynamic model is found to accurately simulate the inelastic deformation and fracture behavior of concrete during compression, splitting, and dynamically induced spall. The work expands the types of materials that can be modeled using peridynamics. A multi-scale methodology for simulating concrete to be used in conjunction with the plasticity model is presented. The work was funded by LDRD 158806.
Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions
Zhang, Liqing
2011-07-01T23:59:59.000Z
Peters August 2011 Major Subject: Industrial Engineering iii ABSTRACT Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions. (August 2011) Liqing Zhang, B.S.; M.S., Tsinghua University, P.R. China Chair... An Illustration of (Q,~s, ~S) Policy ( m = ? s1n?Qn C ? + 1 ) . . . . . . . . 52 5 Optimal Policies for Special Case . . . . . . . . . . . . . . . . . . . . 71 6 Influence of Parameter K . . . . . . . . . . . . . . . . . . . . . . . . 74 7 Influence...
The comparison of the 3-fluid dynamic model with experimental data
Kizka, V A
2015-01-01T23:59:59.000Z
The method of comparison of theoretical predictions with experimental data had been developed.This method allows estimate the quality of theory. Published theoretical data of the three-fluid dynamic (3FD) model applied to the experimental data from heavy-ion collisions at the energy range $\\sqrt{s_{NN}}\\,=\\,2.7 - 63$ GeV were used as example of application of the developed methodology.
The comparison of the 3-fluid dynamic model with experimental data
V. A. Kizka
2015-08-13T23:59:59.000Z
The method of comparison of theoretical predictions with experimental data had been developed.This method allows estimate the quality of theory. Published theoretical data of the three-fluid dynamic (3FD) model applied to the experimental data from heavy-ion collisions at the energy range $\\sqrt{s_{NN}}\\,=\\,2.7 - 63$ GeV were used as example of application of the developed methodology.
Griffith, Daniel Todd
2005-02-17T23:59:59.000Z
computation and evaluation of partial derivatives with minimal user coding. The key results in this dissertation details the use of OCEA through a number of computational studies in estimation and dynamical modeling. Several prototype problems are studied... Embedding Method), has been recently developed which shows promise for efficient computation and evaluation of partial derivatives. For a rather arbitrary sequentially substituted set of functions, coded in FORTRAN 90, OCEA invokes operator overloading...
A spectral transform dynamical core option within the Community Atmosphere Model (CAM4)
Evans, Katherine J [ORNL; Mahajan, Salil [ORNL; Branstetter, Marcia L [ORNL; McClean, Julie L. [Scripps Institute of Oceanography; Caron, Julie M. [National Center for Atmospheric Research (NCAR); Maltrud, Matthew E. [Los Alamos National Laboratory (LANL); Hack, James J [ORNL; Bader, David C [ORNL; Neale, Rich [National Center for Atmospheric Research (NCAR)
2014-01-01T23:59:59.000Z
A spectral transform dynamical core with an 85 spectral truncation resolution (T85) within the Community Atmosphere Model (CAM), version 4, is evaluated within the recently released Community Earth System Model, version 1.0 (CESM) global climate model. The spectral dynamical core option provides a well-known base within the climate model community from which to assess climate behavior and statistics, and its relative computational efficiency for smaller computing platforms allows it to be extended to perform climate length simulations using high-resolution configurations in the near term. To establish the characteristics of the CAM4 T85, an ensemble of simulations covering the present day observational period using forced sea surface temperatures and prescribed sea-ice extent are evaluated. Overall, the T85 ensemble attributes and biases are similar to a companion ensemble of simulations using the one degree finite volume (FV1) dynamical core, relative to observed and model derived datasets. Notable improvements with T85 compared to FV1 include the representation of wintertime Arctic sea level pressure and summer precipitation over the Western Indian subcontinent. The mean and spatial patterns of the land surface temperature trends over the AMIP period are generally well simulated with the T85 ensemble relative to observations, however the model is not able to capture the extent nor magnitude of changes in temperature extremes over the boreal summer, where the changes are most dramatic. Biases in the wintertime Arctic surface temperature and annual mean surface stress fields persist with T85 as with the CAM3 version of T85.
Advanced High-Temperature Reactor Dynamic System Model Development: April 2012 Status
Qualls, A.L.; Cetiner, M.S.; Wilson, T.L., Jr.
2012-04-30T23:59:59.000Z
The Advanced High-Temperature Reactor (AHTR) is a large-output fluoride-salt-cooled high-temperature reactor (FHR). An early-phase preconceptual design of a 1500 MW(e) power plant was developed in 2011 [Refs. 1 and 2]. An updated version of this plant is shown as Fig. 1. FHRs feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. The AHTR is designed to be a “walk away” reactor that requires no action to prevent large off-site releases following even severe reactor accidents. This report describes the development of dynamic system models used to further the AHTR design toward that goal. These models predict system response during warmup, startup, normal operation, and limited off-normal operating conditions. Severe accidents that include a loss-of-fluid inventory are not currently modeled. The scope of the models is limited to the plant power system, including the reactor, the primary and intermediate heat transport systems, the power conversion system, and safety-related or auxiliary heat removal systems. The primary coolant system, the intermediate heat transport system and the reactor building structure surrounding them are shown in Fig. 2. These systems are modeled in the most detail because the passive interaction of the primary system with the surrounding structure and heat removal systems, and ultimately the environment, protects the reactor fuel and the vessel from damage during severe reactor transients. The reactor silo also plays an important role during system warmup. The dynamic system modeling tools predict system performance and response. The goal is to accurately predict temperatures and pressures within the primary, intermediate, and power conversion systems and to study the impacts of design changes on those responses. The models are design tools and are not intended to be used in reactor qualification. The important details to capture in the primary system relate to flows within the reactor vessel during severe events and the resulting temperature profiles (temperature and duration) for major components. Critical components include the fuel, reactor vessel, primary piping, and the primary-to-intermediate heat exchangers (P-IHXs). The major AHTR power system loops are shown in Fig. 3. The intermediate heat transfer system is a group of three pumped salt loops that transports the energy produced in the primary system to the power conversion system. Two dynamic system models are used to analyze the AHTR. A Matlab/Simulink?-based model initiated in 2011 has been updated to reflect the evolving design parameters related to the heat flows associated with the reactor vessel. The Matlab model utilizes simplified flow assumptions within the vessel and incorporates an empirical representation of the Direct Reactor Auxiliary Cooling System (DRACS). A Dymola/Modelica? model incorporates a more sophisticated representation of primary coolant flow and a physics-based representation of the three-loop DRACS thermal hydraulics. This model is not currently operating in a fully integrated mode. The Matlab model serves as a prototype and provides verification for the Dymola model, and its use will be phased out as the Dymola model nears completion. The heat exchangers in the system are sized using spreadsheet-based, steady-state calculations. The detail features of the heat exchangers are programmed into the dynamic models, and the overall dimensions are used to generate realistic plant designs. For the modeling cases where the emphasis is on understanding responses within the intermediate and primary systems, the power conversion system may be modeled as a simple boundary condition at the intermediate-to-power conversion system heat exchangers.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Users of the VEMAP Portal can access input files of numerical data that include monthly and daily files of geographic data, soil and site files, scenario files, etc. Model results from Phase I, the Equilibrium Response datasets, are available through the NCAR anonymous FTP site at http://www.cgd.ucar.edu/vemap/vresults.html. Phase II, Transient Dynamics, include climate datasets, models results, and analysis tools. Many supplemental files are also available from the main data page at http://www.cgd.ucar.edu/vemap/datasets.html.
Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed
Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li [Southeast University, Nanjing (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education
2008-05-15T23:59:59.000Z
Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.
Shu He; Liwei Duan; Qing-Hu Chen
2015-03-14T23:59:59.000Z
In this paper, the finite size Dicke model of arbitrary number of qubits is solved analytically in an unified way within extended coherent states. For the $N=2k$ or $2k-1$ Dicke models ($k$ is an integer), the $G$-function, which is only an energy dependent $k \\times k$ determinant, is derived in a transparent manner. The regular spectrum is completely and uniquely given by stable zeros of the $G$-function. The closed-form exceptional eigenvalues are also derived. The level distribution controlled by the pole structure of the $G$-functions suggests non-integrability for $N>1$ model at any finite coupling in the sense of recent criterion in literature. A preliminary application to the exact dynamics of genuine multipartite entanglement in the finite $N$ Dicke model is presented using the obtained exact solutions.
Dynamic nuclear renography kinetic analysis: Four-compartment model for assessing kidney function
Raswan, T. R., E-mail: tara.raissa@gmail.com; Haryanto, F., E-mail: tara.raissa@gmail.com [Department of Physics, Nuclear Physics and Biophysics Research Group, Institut Teknologi Bandung, Bandung (Indonesia)
2014-09-30T23:59:59.000Z
Dynamic nuclear renography method produces TACs of kidneys and bladder. Multiple TACs data can be further analyzed to obtain the overview of urinary system's condition. Tracer kinetic analysis was performed using four-compartment models. The system's model consist of four irreversible compartment with four transport constants (k1, k2, k3 and k4). The mathematical expressions of tracer's distributions is fitted to experimental data (TACs) resulting in model constants. This transport constants represent the urinary system behavior, and later can be used for analyzing system's condition. Different intervals of kinetics parameter are clearly shown by abnormal system with respect to the normal one. Furthermore, the system with delayed uptake has 82% lower uptake parameters (k1 and k2) than normal one. Meanwhile, the system with prolonged clearance time has its kinetics parameters k3 or k4 lower than the others. This model is promising for quantitatively describe urinary system's function especially if supplied with more data.
Deep ACS Imaging in the Globular Cluster NGC6397: Dynamical Models
Jarrod R. Hurley; Michael M. Shara; Harvey B. Richer; Ivan R. King; D. Saul Davis; Jason S. Kalirai; Brad M. S. Hansen; Aaron Dotter; Jay Anderson; Gregory G. Fahlman; R. Michael Rich
2008-02-28T23:59:59.000Z
We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and account for the tidal field of the Galaxy. We focus on the results of a simulation that began with 100000 objects (stars and binaries), 5% primordial binaries and Population II metallicity. After 16 Gyr of evolution the model cluster has about 20% of the stars remaining and has reached core-collapse. We compare the color-magnitude diagrams of the model at this age for the central region and an outer region corresponding to the observed field of NGC6397 (about 2-3 half-light radii from the cluster centre). This demonstrates that the white dwarf population in the outer region has suffered little modification from dynamical processes - contamination of the luminosity function by binaries and white dwarfs with non-standard evolution histories is minimal and should not significantly affect measurement of the cluster age. We also show that the binary fraction of main-sequence stars observed in the NGC6397 field can be taken as representative of the primordial binary fraction of the cluster. For the mass function of the main-sequence stars we find that although this has been altered significantly by dynamics over the cluster lifetime, especially in the central and outer regions, that the position of the observed field is close to optimal for recovering the initial mass function of the cluster stars (below the current turn-off mass). More generally we look at how the mass function changes with radius in a dynamically evolved stellar cluster and suggest where the best radial position to observe the initial mass function is for clusters of any age.
Dai, Yang
Protein folding dynamics in lattice model with physical movement S¨ema Kachalo, Hsiao-Mei Lu analysis of the kinetic energy landscape. I. INTRODUCTION The dynamics of protein folding has been studied exten- sively [1, 35]; A remarkable empirical observation is that protein folding rates are well
Gutowski, William J.; Prusa, Joseph M.; Smolarkiewicz, Piotr K.
2012-05-08T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the "physics" of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited. 3a. EULAG Advances EULAG is a non-hydrostatic, parallel computational model for all-scale geophysical flows. EULAG's name derives from its two computational options: EULerian (flux form) or semi-LAGrangian (advective form). The model combines nonoscillatory forward-in-time (NFT) numerical algorithms with a robust elliptic Krylov solver. A signature feature of EULAG is that it is formulated in generalized time-dependent curvilinear coordinates. In particular, this enables grid adaptivity. In total, these features give EULAG novel advantages over many existing dynamical cores. For EULAG itself, numerical advances included refining boundary conditions and filters for optimizing model performance in polar regions. We also added flexibility to the model's underlying formulation, allowing it to work with the pseudo-compressible equation set of Durran in addition to EULAG's standard anelastic formulation. Work in collaboration with others also extended the demonstrated range of validity of soundproof models, showing that they are more broadly applicable than some had previously thought. Substantial testing of EULAG included application and extension of the Jablonowski-Williamson baroclinic wave test - an archetype of planetary weather - and further analysis of multi-scale interactions arising from collapse of temperature fronts in both the baroclinic wave test and simulations of the Held-Suarez idealized climate. These analyses revealed properties of atmospheric gravity waves not seen in previous work and further demonstrated the ability of EULAG to simulate realistic behavior over several orders of magnitude of length scales. Additional collaborative work enhanced capability for modeling atmospheric flows with adaptive moving meshes and demonstrated the ability of EULAG to move into petascale computing. 3b. CAM-EULAG Advances We have developed CAM-EULAG in collaboration with former project postdoc, now University of Cape Town Assistant Professor, Babatunde Abiodun. Initial study documented good model performance in aqua-planet simulations. In particular, we showed that the grid adaptivity (stretching) implemented in CAM-EULAG allows higher resolution in selected regions without causing anomalous behavior such as spurious wave reflection. We then used the stretched-grid version to analyze simulated extreme precipitation events in West Africa, comparing the precipitation and event environment with observed behavior. The model simulates fairly well the spatial scale and the interannual and intraseasonal variability of the extreme events, although its extreme precipitation intensity is weaker than observed. In addition, both observations and the simulations show possible forcing of extreme events by African easterly waves. 3c. Other Contributions Through our collaborations, we have made contributions to a wide range of outcomes. For research focused on terrestrial behavior, these have included (1) upwind schemes for gas dynamics, (2) a nonlinear perspective on the dynamics of the Madden-Julian Oscillation, (3) numerical realism of thermal co
reproduces benthic algae and macro-invertebrates dynamics. Algae biomass = growth - death loss - predation influences on algae and macro-invertebrates dynamics will be introduced in the predator-prey model: - at increasing flow velocity high nutrient availability, algae erosion and macro-invertebrate drag
Pugliese, Andrea
The role of sex in parasite dynamics: Model simulations on transmission of Heligmosomoides Abstract We investigated possible mechanisms that could cause sex-biased parasite transmission. Two, not mutually exclusive, hypotheses were examined: that sex-bi- ased parasite transmission
Economou, Demetre J.
2011-01-01T23:59:59.000Z
PHYSICAL REVIEW E 83, 046405 (2011) Dynamic model of streamer coupling for the homogeneity. Economou Department of Chemical and Biomolecular Engineering, Plasma Processing Laboratory, University 2011; published 18 April 2011) A streamer coupling theory is developed to describe the formation
Kamal, Sameer A. (Sameer Ahmed)
2009-01-01T23:59:59.000Z
This thesis describes the use of a distributed hydrology model in conjunction with a Factor of Safety (FS) algorithm to predict dynamic landslide susceptibility for a humid basin in Puerto Rico. The Mameyes basin, located ...
Barth, Eric J.
. To support one component of the model, a regenerative heat exchanger is described using a lumped parameter on its physical aspect ratio. Finally, the heat exchanger model is experimentally verified. 1 of this type is described analytically with a physics-based, high-order, lumped- parameter, dynamic model
Paris-Sud XI, Université de
Kinematic and dynamic model-based control of wheeled mobile manipulators: a unified framework aims at providing a unified modeling framework for the reactive control of wheeled mobile manipulators systems is given. This modeling framework is particularly well suited for reactive control approaches
Prusa, Joseph
2012-05-08T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAGÃ¢Â?Â?s advanced dynamics core with the Ã¢Â?Â?physicsÃ¢Â?Â of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer- reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.
Bo Yang; Xihua Xu; John Z. F. Pang; Christopher Monterola
2015-04-06T23:59:59.000Z
We propose a framework for constructing microscopic traffic models from microscopic acceleration patterns that can in principle be experimental measured and proper averaged. The exact model thus obtained can be used to justify the consistency of various popular models in the literature. Assuming analyticity of the exact model, we suggest that a controlled expansion around the constant velocity, uniform headway "ground state" is the proper way of constructing various different effective models. Assuming a unique ground state for any fixed average density, we discuss the universal properties of the resulting effective model, focusing on the emergent quantities of the coupled non-linear ODEs. These include the maximum and minimum headway that give the coexistence curve in the phase diagram, as well as an emergent intrinsic scale that characterizes the strength of interaction between clusters, leading to non-trivial cluster statistics when the unstable ground state is randomly perturbed. Utilizing the universal properties of the emergent quantities, a simple algorithm for constructing an effective traffic model is also presented. The algorithm tunes the model with statistically well-defined quantities extracted from the flow-density plot, and the resulting effective model naturally captures and predicts many quantitative and qualitative empirical features of the highway traffic, especially in the presence of an on-ramp bottleneck. The simplicity of the effective model provides strong evidence that stochasticity, diversity of vehicle types and modeling of complicated individual driving behaviors are \\emph{not} fundamental to many observations of the complex spatiotemporal patterns in the real traffic dynamics. We also propose the nature of the congested phase can be well characterized by the long lasting transient states of the effective model, from which the wide moving jams evolve.
Thermodynamic model of a thermal storage air conditioning system with dynamic behavior
Fleming, E; Wen, SY; Shi, L; da Silva, AK
2013-12-01T23:59:59.000Z
A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system's dynamic behavior, such as a dynamic air flow rate into the vehicle's cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle's cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid-air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semianalytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid-air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system experimental data for solidification using paraffin wax as the PCM. Through modeling, we demonstrate the importance of capturing the airside heat exchange impact on system performance, and we investigate system response to dynamic operating conditions, e.g., air recirculation. (C) 2013 Elsevier Ltd. All rights reserved.
Hewitt, Natalie Case
2012-07-16T23:59:59.000Z
Dynamics During a Prymnesium parvum Bloom: The Importance of Inflows and Allelopathic Relationships on Bloom Dynamics. (May 2011) Natalie Case Hewitt, B.S., Brown University Chair of Advisory Committee: Dr. Daniel L Roelke Harmful algal blooms? global... .................................................................... 24 2.7 Toxin Equations .......................................................................... 28 2.7.1 Martines et al. 2009 ......................................................... 28 2.7.2 Grover et al. 2010...
Dynamics of many-body localisation in a translation invariant quantum glass model
Merlijn van Horssen; Emanuele Levi; Juan P. Garrahan
2015-05-26T23:59:59.000Z
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.
Miyamoto, Tadashi; Kaneko, Kunihiko
2015-01-01T23:59:59.000Z
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...
Watts, N.L.; Kaars Sijpestein, C.H.; Osai, L.N.; Okoli, O.C. (Shell Petroleum Development Co. of Nigeria, Lagos (Nigeria))
1991-08-01T23:59:59.000Z
Previous studies of fault sealing have addressed possible fault leakage during secondary migration due to the effects of increased hydrocarbon-water capillary pressure, fracturing, or small-scale incremental fault movements. Of equal importance to production geologists is the failure and leakage of faults during field development due to differential depletion of adjacent fault blocks. This paper examines the unique problems associated with this dynamic leakage of faults. It is theoretically shown that the fault sealing mechanism, and the extent of the seal, directly influences the failure process which in turn results in a variety of favorable and unfavorable effects on field development. The qualitative models give considerable insight into such aspects as oil-column expansion and resaturation losses, interfault block aquifer support (with important implications to material balance calculations), possible leakage or spillage of oil across faults, and potential fault failure during (re)injection projects. Examples of dynamic fault leakage are presented from selected fields of the Niger delta.
Rheological properties vs Local Dynamics in model disordered materials at Low Temperature
C. Fusco; T. Albaret; A. Tanguy
2014-03-31T23:59:59.000Z
We study the rheological response at low temperature of a sheared model disordered material as a function of the bond rigidity. We find that the flow curves follow a Herschel-Bulkley law, whatever is the bond rigidity, with an exponent close to 0.5. Interestingly, the apparent viscosity can be related to a single relevant time scale $t_{rel}$, suggesting a strong connection between the local dynamics and the global mechanical behaviour. We propose a model based on the competition between the nucleation and the avalanche-like propagation of spatial strain heterogeneities. This model can explain the Herschel-Bulkley exponent on the basis of the size dependence of the heterogeneities on the shear rate.
Testing for dynamical dark energy models with redshift-space distortions
Tsujikawa, Shinji [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Felice, Antonio De [ThEP's CRL, NEP, The Institute for Fundamental Study, Naresuan University, Phitsanulok 65000 (Thailand); Alcaniz, Jailson, E-mail: shinji@rs.kagu.tus.ac.jp, E-mail: antoniod@nu.ac.th, E-mail: alcaniz@on.br [Departamento de Astronomia, Observatório Nacional, 20921-400 Rio de Janeiro - RJ (Brazil)
2013-01-01T23:59:59.000Z
The red-shift space distortions in the galaxy power spectrum can be used to measure the growth rate of matter density perturbations ?{sub m}. For dynamical dark energy models in General Relativity we provide a convenient analytic formula of f(z)?{sub 8}(z) written as a function of the redshift z, where f = dln ?{sub m}/dln a (a is the cosmological scale factor) and ?{sub 8} is the rms amplitude of over-density at the scale 8 h{sup ?1} Mpc. Our formula can be applied to the models of imperfect fluids, quintessence, and k-essence, provided that the dark energy equation of state w does not vary significantly and that the sound speed is not much smaller than 1. We also place observational constraints on dark energy models of constant w and tracking quintessence from the recent data of red-shift space distortions.
Fabrizio Clarelli; Cristiana Di Russo; Roberto Natalini; Magali Ribot
2014-08-09T23:59:59.000Z
In this article, we study in details the fluid dynamics system proposed in Clarelli et al (2013) to model the formation of cyanobacteria biofilms. After analyzing the linear stability of the unique non trivial equilibrium of the system, we introduce in the model the influence of light and temperature, which are two important factors for the development of cyanobacteria biofilm. Since the values of the coefficients we use for our simulations are estimated through information found in the literature, some sensitivity and robustness analyses on these parameters are performed. All these elements enable us to control and to validate the model we have already derived and to present some numerical simulations in the 2D and the 3D cases.
Seto, Ryohei; Auernhammer, Günter K; Briesen, Heiko
2012-01-01T23:59:59.000Z
A method to couple interparticle contact models with Stokesian dynamics (SD) is introduced to simulate colloidal aggregates under flow conditions. The contact model mimics both the elastic and plastic behavior of the cohesive connections between particles within clusters. Owing to this, clusters can maintain their structures under low stress while restructuring or even breakage may occur under sufficiently high stress conditions. SD is an efficient method to deal with the long-ranged and many-body nature of hydrodynamic interactions for low Reynolds number flows. By using such a coupled model, the restructuring of colloidal aggregates under stepwise increasing shear flows was studied. Irreversible compaction occurs due to the increase of hydrodynamic stress on clusters. Results show that the greater part of the fractal clusters are compacted to rod-shaped packed structures, while the others show isotropic compaction.
Modeling the influence of polls on elections: a population dynamics approach
Hyman, James M [Los Alamos National Laboratory; Restrepo, Juan M [UNIV OF ARIZONA; Rael, Rosalyn C [UNIV OF ARIZONA
2009-01-01T23:59:59.000Z
We propose a population dynamics model for quantifying the effects of polling data on the outcome of multi-party elections decided by a majority-rule voting process. We divide the population into two groups: committed voters impervious to polling data, and susceptible voters whose decision to vote is influenced by data, depending on its reliability. This population-based approach to modeling the process sidesteps the problem of upscaling models based upon the choices made by individuals. We find releasing poll data is not advantageous to leading candidates, but it can be exploited by those closely trailing. The analysis identifies the particular type of voting impetus at play in different stages of an election and could help strategists optimize their influence on susceptible voters.
Dr. Chenn Zhou
2008-10-15T23:59:59.000Z
Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process.
Schmidt, W; Niemeyer, J C
2006-01-01T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the sub...
Modelling rogue waves through exact dynamical lump soliton controlled by ocean currents
Kundu, Anjan; Naskar, Tapan
2012-01-01T23:59:59.000Z
The ocean rogue wave, one of the mysteries of nature, has not yet been understood or modelled satisfactorily, in spite of being in the intense lime-light in recent years and the concept spreadin fast to other disciplines. Rogue waves are extraordinarily high and steep surface waves. However, most of their theoretical models and experimental observations, excluding a few are one-dimensional, admitting limited high intensity and steepness. We propose here a novel two-dimensional integrable nonlinear Schroedinger equation allowing an exact lump-soliton with special asymmetry and directional preference. The soliton can appear on surface waves making a hole just before surging up high, with adjustable height and steepness and disappear again followed by the hole. The dynamics, speed and the duration of the soliton is controlled by ocean currents. These desirable properties make our exact model promising for describing deep sea large rogue waves.
Thermodynamic and dynamic anomalous behavior in the TIP4P/? water model
Raul Fuentes-Azcatl; Marcia C. Barbosa
2015-08-11T23:59:59.000Z
The model Tip4p/{\\epsilon} for water is tested for the presence of thermodynamic and dy- namic anomalies. Molecular dynamic simulations for this model were performed and we show that for this system the density versus temperature at constant pressure ex- hibits a maximum. In addition we also show that the diffusion coefficient versus density at constant temperature has a maximum and a minimum. The anomalous behavior of the density and of the diffusion coefficient obey the water hierachy. The results for the Tip4p- are consistent with experiments and when compared with the Tip4p-2005 model show similar results a variety of physical properties and better performance for the dielectric constant.
Reeves, Geoffrey D [Los Alamos National Laboratory; Friedel, Reiner H W [Los Alamos National Laboratory; Chen, Yue [Los Alamos National Laboratory; Koller, Josef [Los Alamos National Laboratory; Henderson, Michael G [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
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.
Modeling Merging Galaxies using MINGA - Improving Restricted N-body by Dynamical Friction
Hanns P. Petsch; Christian Theis
2008-10-03T23:59:59.000Z
Modeling interacting galaxies to reproduce observed systems is still a challenge due to the extended parameter space (among other problems). Orbit and basic galaxy parameters can be tackled by fast simulation techniques like the restricted N-body method, applied in the fundamental work by Toomre & Toomre (1972). This approach allows today for the study of millions of models in a short time. One difficulty for the classical restricted N-body method is the missing orbital decay, not allowing for galaxy mergers. Here we present an extension of the restricted N-body method including dynamical friction. This treatment has been developed by a quantitative comparison with a set of self-consistent merger simulations. By varying the dynamical friction (formalism, strength and direction), we selected the best-fitting parameters for a set of more than 250000 simulations. We show that our treatment reliably reproduces the orbital decay and tidal features of merging disk galaxies for mass ratios up to q=1/3 between host and satellite. We implemented this technique into our genetic algorithm based modeling code MINGA and present first results.
Concepts and Their Dynamics: A Quantum-Theoretic Modeling of Human Thought
Diederik Aerts; Liane Gabora; Sandro Sozzo
2013-01-05T23:59:59.000Z
We analyze different aspects of our quantum modeling approach of human concepts, and more specifically focus on the quantum effects of contextuality, interference, entanglement and emergence, illustrating how each of them makes its appearance in specific situations of the dynamics of human concepts and their combinations. We point out the relation of our approach, which is based on an ontology of a concept as an entity in a state changing under influence of a context, with the main traditional concept theories, i.e. prototype theory, exemplar theory and theory theory. We ponder about the question why quantum theory performs so well in its modeling of human concepts, and shed light on this question by analyzing the role of complex amplitudes, showing how they allow to describe interference in the statistics of measurement outcomes, while in the traditional theories statistics of outcomes originates in classical probability weights, without the possibility of interference. The relevance of complex numbers, the appearance of entanglement, and the role of Fock space in explaining contextual emergence, all as unique features of the quantum modeling, are explicitly revealed in this paper by analyzing human concepts and their dynamics.
Deep ACS Imaging in the Globular Cluster NGC6397: Dynamical Models
Hurley, Jarrod R; Richer, Harvey B; King, Ivan R; Davis, D Saul; Kalirai, Jason S; Hansen, Brad M S; Dotter, Aaron; Anderson, Jay; Fahlman, Gregory G; Rich, R Michael
2008-01-01T23:59:59.000Z
We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and account for the tidal field of the Galaxy. We focus on the results of a simulation that began with 100000 objects (stars and binaries), 5% primordial binaries and Population II metallicity. After 16 Gyr of evolution the model cluster has about 20% of the stars remaining and has reached core-collapse. We compare the color-magnitude diagrams of the model at this age for the central region and an outer region corresponding to the observed field of NGC6397 (about 2-3 half-light radii from the cluster centre). This demonstrates that the white dwarf population in the outer region has suffered little modification from dynamical processes - contamination of the luminosity function by binaries and white dwarfs with non-standard evolution histories is minimal and should not significantly a...
Use of a dynamic simulation model to understand nitrogen cycling in the middle Rio Grande, NM.
Meixner, Tom (University of Arizona, Tucson, AZ); Tidwell, Vincent Carroll; Oelsner, Gretchen (University of Arizona, Tucson, AZ); Brooks, Paul (University of Arizona, Tucson, AZ); Roach, Jesse D.
2008-08-01T23:59:59.000Z
Water quality often limits the potential uses of scarce water resources in semiarid and arid regions. To best manage water quality one must understand the sources and sinks of both solutes and water to the river system. Nutrient concentration patterns can identify source and sink locations, but cannot always determine biotic processes that affect nutrient concentrations. Modeling tools can provide insight into these large-scale processes. To address questions about large-scale nitrogen removal in the Middle Rio Grande, NM, we created a system dynamics nitrate model using an existing integrated surface water--groundwater model of the region to evaluate our conceptual models of uptake and denitrification as potential nitrate removal mechanisms. We modeled denitrification in groundwater as a first-order process dependent only on concentration and used a 5% denitrification rate. Uptake was assumed to be proportional to transpiration and was modeled as a percentage of the evapotranspiration calculated within the model multiplied by the nitrate concentration in the water being transpired. We modeled riparian uptake as 90% and agricultural uptake as 50% of the respective evapotranspiration rates. Using these removal rates, our model results suggest that riparian uptake, agricultural uptake and denitrification in groundwater are all needed to produce the observed nitrate concentrations in the groundwater, conveyance channels, and river as well as the seasonal concentration patterns. The model results indicate that a total of 497 metric tons of nitrate-N are removed from the Middle Rio Grande annually. Where river nitrate concentrations are low and there are no large nitrate sources, nitrate behaves nearly conservatively and riparian and agricultural uptake are the most important removal mechanisms. Downstream of a large wastewater nitrate source, denitrification and agricultural uptake were responsible for approximately 90% of the nitrogen removal.
Identification of powered parafoil-vehicle dynamics from modelling and flight test data
Hur, Gi-Bong
2006-08-16T23:59:59.000Z
S consisting of N particles P1,...,PN, suppose that n -m gen- eralized speeds have been introduced, and let vPir denote the rth partial velocity of Pi. Then, if Ri is the resultant of all contact and body forces acting on Pi, then the n -m quantities F1,...,Fn-m...IDENTIFICATION OF POWERED PARAFOIL-VEHICLE DYNAMICS FROM MODELLING AND FLIGHT TEST DATA A Dissertation by GI-BONG HUR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...
Analysis of Block Preconditioners for Models of Coupled Magma/Mantle Dynamics
Rhebergen, Sander; Wells, Garth N.; Katz, Richard F.; Wathen, Andrew J.
2014-08-19T23:59:59.000Z
F08, 76M10, 86A17, 86-08 DOI. 10.1137/130946678 1. Introduction. The mantle of Earth extends from the bottom of the crust to the top of the iron core, some 3000 km below. Mantle rock, composed of silicate min- erals, behaves as an elastic solid... -dimensional, magma/mantle dynamics of subduction, even though this is an area of active research [22, 39]. Such models require highly refined compu- tational meshes, resulting in very large systems of algebraic equations. To solve these systems efficiently, iterative...
Dynamic control of quantum geometric heat flux in a nonequilibrium spin-boson model
Tian Chen; Xiang-Bin Wang; Jie Ren
2013-04-24T23:59:59.000Z
We study the quantum geometric heat flux in the nonequilibrium spin-boson model. By adopting the noninteracting-blip approximation that is able to accommodate the strong system-bath coupling, we show that there exists a nonzero geometric heat flux only when the two-level system is nondegenerate. Moreover, the pumping, no pumping, and dynamic control of geometric heat flux are discussed in detail, compared to the results with Redfield weak-coupling approximation. In particular, the geometric energy transfer induced by modulation of two system-bath couplings is identified, which is exclusive to quantum transport in the strong system-bath coupling regime.
A new single-dynamical-scalar-field model of dark energy
Chao-Guang Huang; Han-Ying Guo
2005-08-06T23:59:59.000Z
A new single-dynamical-scalar-field model of dark energy is proposed, in which either higher derivative terms nor structures of extra dimension are needed. With the help of a fixed background vector field, the parameter for the effective equation of state of dark energy may cross $w=-1$ in the evolution of the universe. After suitable choice of the potential, the crossing $w=-1$ and transition from decelerating to accelerating occur at $z\\approx 0.2$ and $z\\approx 1.7$, respectively.
Noise-induced cooperative dynamics and its control in coupled neuron models
B. Hauschildt; N. B. Janson; A. Balanov; E. Schoell
2006-10-04T23:59:59.000Z
We investigate feedback control of the cooperative dynamics of two coupled neural oscillators that is induced merely by external noise. The interacting neurons are modelled as FitzHugh-Nagumo systems with parameter values at which no autonomous oscillations occur, and each unit is forced by its own source of random fluctuations. Application of delayed feedback to only one of two subsystems is shown to be able to change coherence and timescales of noise induced oscillations either in the given subsystem, or globally. It is also able to induce or to suppress stochastic synchronization under certain conditions.
Identification of powered parafoil-vehicle dynamics from modelling and flight test data
Hur, Gi-Bong
2006-08-16T23:59:59.000Z
S consisting of N particles P1,...,PN, suppose that n -m gen- eralized speeds have been introduced, and let vPir denote the rth partial velocity of Pi. Then, if Ri is the resultant of all contact and body forces acting on Pi, then the n -m quantities F1,...,Fn-m...IDENTIFICATION OF POWERED PARAFOIL-VEHICLE DYNAMICS FROM MODELLING AND FLIGHT TEST DATA A Dissertation by GI-BONG HUR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree...
Cooling Energy Demand Evaluation by Meansof Regression Models Obtained From Dynamic Simulations
Catalina, T.; Virgone, J.
2011-01-01T23:59:59.000Z
was calculated to be -8.78oC (Moscow in January) and maximum of 42.9 oC (Abu-Dhabi in August). The hourly values of outdoor air temperature and solar radiation were obtained using Trnsys (Trnsys, 2006) meteonorm files. b) Glazing surface and distribution... the ,,black-box,, function, dynamic simulations were conducted using Trnsys 16 software (Trnsys, 2005). The Trnsys building model, known as, Type 56, is compliant with general requirements of European Directive on the energy performance of buildings...
Mathieu, Johanna L.; Callaway, Duncan S.; Kiliccote, Sila
2011-08-15T23:59:59.000Z
Controlling electric loads to deliver power system services presents a number of interesting challenges. For example, changes in electricity consumption of Commercial and Industrial (C&I) facilities are usually estimated using counterfactual baseline models, and model uncertainty makes it difficult to precisely quantify control responsiveness. Moreover, C&I facilities exhibit variability in their response. This paper seeks to understand baseline model error and demand-side variability in responses to open-loop control signals (i.e. dynamic prices). Using a regression-based baseline model, we define several Demand Response (DR) parameters, which characterize changes in electricity use on DR days, and then present a method for computing the error associated with DR parameter estimates. In addition to analyzing the magnitude of DR parameter error, we develop a metric to determine how much observed DR parameter variability is attributable to real event-to-event variability versus simply baseline model error. Using data from 38 C&I facilities that participated in an automated DR program in California, we find that DR parameter errors are large. For most facilities, observed DR parameter variability is likely explained by baseline model error, not real DR parameter variability; however, a number of facilities exhibit real DR parameter variability. In some cases, the aggregate population of C&I facilities exhibits real DR parameter variability, resulting in implications for the system operator with respect to both resource planning and system stability.
van Thienen, Peter
by a description of the implementation of solid state phase transitions of crustal and mantle material included Rc phase Rayleigh number gh3 0 S melt productivity function s-1 S entropy change upon full in the models. Finally, the implementa- tion of partial melting of crustal and mantle material and associated
Ab initio molecular dynamics simulation of proton hopping in a model polymer membrane
Devanathan, Ramaswami; Idupulapati, Nagesh B.; Baer, Marcel D.; Mundy, Christopher J.; Dupuis, Michel
2013-12-10T23:59:59.000Z
We report the results of ab initio molecular dynamics simulations of a model NafionTM polymer membrane initially equilibrated using classical molecular dynamics simulations. We studied three hydration levels (?) of 3, 9, and 15 H2O/SO3- corresponding to dry, hydrated and saturated fuel cell membrane, respectively. The barrier for proton transfer from the SO3-–H3O+ contact ion pair to a solvent-separated ion pair decreased from 2.3 kcal/mol for ? = 3 to 0.8 kcal/mol for ? = 15. The barrier for proton transfer between two water molecules was in the range from 0.7 to 0.8 kcal/mol for the ? values studied. The number of proton shuttling events between a pair of water molecules is an order of magnitude more than the number of proton hops across three distinct water molecules. The proton diffusion coefficient at ? = 15 is about 0.9x10-5 cm2/s, which is in good agreement with experiment and our previous quantum hopping molecular dynamics simulations.
Dynamical model of mesoscales in z-coordinates V.M. Canuto a,b,*, M.S. Dubovikov a,c
Dynamical model of mesoscales in z-coordinates V.M. Canuto a,b,*, M.S. Dubovikov a,c a NASA Abstract Using the equations of the dynamical mesoscale model developed previously [Ocean Modell. (2004) 8, 1 30], we derive a mesoscale model in z-coordinates to be used in coarse resolution OGCMs. We
Forest Fire Model as a Supercritical Dynamic Model in Financial Systems
Lee, Deokjae; Lee, Jeho; Kahng, B
2015-01-01T23:59:59.000Z
Recently, large-scale cascading failures in complex systems have garnered substantial attention. Such extreme events have been treated as an integral part of the self-organized criticality (SOC). Recent empirical work has suggested that some extreme events systematically deviate from the SOC paradigm, requiring a different theoretical framework. We shed additional theoretical light on this possibility by studying financial crisis. We build our model of financial crisis on the well-known forest fire model in scale-free networks. Our analysis shows a non-trivial scaling feature indicating supercritical behavior, which is independent of system size. Extreme events in the supercritical state result from bursting of a fat bubble, seeds of which are sown by a protracted period of a benign financial environment with few shocks. Our findings suggest that policymakers can control the magnitude of financial meltdowns by keeping the economy operating within reasonable duration of a benign environment.
Dynamics of a Simple Model for Turbulence of the Second Sound in Helium II
B. V. Chirikov; V. G. Davidovsky
2000-06-13T23:59:59.000Z
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.
Radial electric field 3D modeling for wire arrays driving dynamic hohlraums on Z.
Mock, Raymond Cecil
2007-06-01T23:59:59.000Z
The anode-cathode structure of the Z-machine wire array results in a higher negative radial electric field (Er) on the wires near the cathode relative to the anode. The magnitude of this field has been shown to anti-correlate with the axial radiation top/bottom symmetry in the DH (Dynamic Hohlraum). Using 3D modeling, the structure of this field is revealed for different wire-array configurations and for progressive mechanical alterations, providing insight for minimizing the negative Er on the wire array in the anode-to-cathode region of the DH. Also, the 3D model is compared to Sasorov's approximation, which describes Er at the surface of the wire in terms of wire-array parameters.
Projecting Low Dimensional Chaos from Spatio-temporal Dynamics in a Model for Plastic Instability
Ritupan Sarmah; G. Ananthakrishna
2013-03-26T23:59:59.000Z
We investigate the possibility of projecting low dimensional chaos from spatiotemporal dynamics of a model for a kind of plastic instability observed under constant strain rate deformation conditions. We first discuss the relationship between the spatiotemporal patterns of the model reflected in the nature of dislocation bands and the nature of stress serrations. We show that at low applied strain rates, there is a one-to-one correspondence with the randomly nucleated isolated bursts of mobile dislocation density and the stress drops. We then show that the model equations are spatiotemporally chaotic by demonstrating the number of positive Lyapunov exponents and Lyapunov dimension scale with the system size at low and high strain rates. Using a modified algorithm for calculating correlation dimension density, we show that the stress-strain signals at low applied strain rates corresponding to spatially uncorrelated dislocation bands exhibit features of low dimensional chaos. This is made quantitative by demonstrating that the model equations can be approximately reduced to space independent model equations for the average dislocation densities, which is known to be low-dimensionally chaotic. However, the scaling regime for the correlation dimension shrinks with increasing applied strain rate due to increasing propensity for propagation of the dislocation bands.
Water Usage for In-Situ Oil Shale Retorting – A Systems Dynamics Model
Earl D. Mattson; Larry Hull; Kara Cafferty
2012-12-01T23:59:59.000Z
A system dynamic model was construction to evaluate the water balance for in-situ oil shale conversion. The model is based on a systems dynamics approach and uses the Powersim Studio 9™ software package. Three phases of an insitu retort were consider; a construction phase primarily accounts for water needed for drilling and water produced during dewatering, an operation phase includes the production of water from the retorting process, and a remediation phase water to remove heat and solutes from the subsurface as well as return the ground surface to its natural state. Throughout these three phases, the water is consumed and produced. Consumption is account for through the drill process, dust control, returning the ground water to its initial level and make up water losses during the remedial flushing of the retort zone. Production of water is through the dewatering of the retort zone, and during chemical pyrolysis reaction of the kerogen conversion. The major water consumption was during the remediation of the insitu retorting zone.
The Global Nuclear Futures Model: A Dynamic Simulation Tool for Energy Strategies
Bixler, N.E. [Sandia National Laboratories, Albuquerque, NM 87185-0748 (United States)
2002-07-01T23:59:59.000Z
The Global Nuclear Futures Model (GNFM) is a dynamic simulation tool that provides an integrated framework to model key aspects of nuclear energy, nuclear materials storage and disposition, global nuclear materials management, and nuclear proliferation risk. It links nuclear energy and other energy shares dynamically to greenhouse gas emissions and twelve other measures of environmental impact. It presents historical data from 1990 to 2000 and extrapolates energy demand through the year 2050. More specifically, it contains separate modules for energy, the nuclear fuel cycle front end, the nuclear fuel cycle back end, defense nuclear materials, environmental impacts, and measures of the potential for nuclear proliferation. It is globally integrated but also breaks out five regions of the world so that environmental impacts and nuclear proliferation concerns can be evaluated on a regional basis. The five regions are the United States of America (USA), The Peoples Republic of China (China), the former Soviet Union (FSU), the OECD nations excluding the USA, and the rest of the world (ROW). (author)
Exact Coherent Structures and Chaotic Dynamics in a Model of Cardiac Tissue
Greg Byrne; Christopher D. Marcotte; Roman O. Grigoriev
2015-01-20T23:59:59.000Z
Unstable nonchaotic solutions embedded in the chaotic attractor can provide significant new insight into chaotic dynamics of both low- and high-dimensional systems. In particular, in turbulent fluid flows, such unstable solutions are referred to as exact coherent structures (ECS) and play an important role in both initiating and sustaining turbulence. The nature of ECS and their role in organizing spatiotemporally chaotic dynamics, however, is reasonably well understood only for systems on relatively small spatial domains lacking continuous Euclidean symmetries. Construction of ECS on large domains and in the presence of continuous translational and/or rotational symmetries remains a challenge. This is especially true for models of excitable media which display spiral turbulence and for which the standard approach to computing ECS completely breaks down. This paper uses the Karma model of cardiac tissue to illustrate a potential approach that could allow computing a new class of ECS on large domains of arbitrary shape by decomposing them into a patchwork of solutions on smaller domains, or tiles, which retain Euclidean symmetries locally.
Paris-Sud XI, Université de
- 1 - 10th IEA Heat Pump Conference 2011, 16 - 19 May 2011, Tokyo, Japan DYNAMIC MODELING OF AN AIR SOURCE HEAT PUMP WATER HEATER Farouk Fardoun, Associate Professor, Department of Industrial Engineering of an air source heat pump water heater (ASHPWH). The mathematical model consists of submodels of the basic
Levashov, Michael Yurievich
2012-01-01T23:59:59.000Z
In this thesis, I present a framework for achieving a stable bounding gait on the LittleDog robot over rough terrain. The framework relies on an accurate planar model of the dynamics, which I assembled from a model of the ...
Hiskens, Ian A.
Turbine Generator Models Ian A. Hiskens, Fellow, IEEE Abstract--The influence of wind turbine generators, singular systems, small disturbance analysis, switching deadlock, wind turbine generator modeling. I. INTRODUCTION THE dynamic behavior of wind turbine generators (WTGs) is quite different to that of synchronous
Schofield, Jeremy
in the article. Reuse of AIP content is subject to the terms at: http of a stochastic model of the dynamics of bond formation. Finally, the Markov model is studied by analyzing profile as the temperature is lowered can be understood in terms of the number of relaxation modes
Ford, Andrew
Env. Sci 310/550 -- Stella or Vensim? Both Stella and Vensim are excellent programs for dynamic modeling, and both are explained and used in Modeling the Environment: 2nd Edition. You can select either program for this course. Previous students' experiences may help you decide which software is best for you
Dynamical modelling of luminous and dark matter in 17 Coma early-type galaxies
J. Thomas; R. P. Saglia; R. Bender; D. Thomas; K. Gebhardt; J. Magorrian; E. M. Corsini; G. Wegner
2007-09-05T23:59:59.000Z
Dynamical models for 17 Coma early-type galaxies are presented. The galaxy sample consists of flattened, rotating as well as non-rotating early-types including cD and S0 galaxies with luminosities between M=-18.79 and M=-22.56. Kinematical long-slit observations cover at least the major and minor axis and extend to 1-4 effective radii. Axisymmetric Schwarzschild models are used to derive stellar mass-to-light ratios and dark halo parameters. In every galaxy models with a dark matter halo match the data better than models without. The statistical significance is over 95 percent for 8 galaxies, around 90 percent for 5 galaxies and for four galaxies it is not significant. For the highly significant cases systematic deviations between observed and modelled kinematics are clearly seen; for the remaining galaxies differences are more statistical in nature. Best-fit models contain 10-50 percent dark matter inside the half-light radius. The central dark matter density is at least one order of magnitude lower than the luminous mass density. The central phase-space density of dark matter is often orders of magnitude lower than in the luminous component, especially when the halo core radius is large. The orbital system of the stars along the major-axis is slightly dominated by radial motions. Some galaxies show tangential anisotropy along the minor-axis, which is correlated with the minor-axis Gauss-Hermite coefficient H4. Changing the balance between data-fit and regularisation constraints does not change the reconstructed mass structure significantly. Model anisotropies tend to strengthen if the weight on regularisation is reduced, but the general property of a galaxy to be radially or tangentially anisotropic, respectively, does not change. (abridged)
Multi-field open inflation model and multi-field dynamics in tunneling
Sugimura, Kazuyuki; Yamauchi, Daisuke; Sasaki, Misao, E-mail: sugimura@yukawa.kyoto-u.ac.jp, E-mail: yamauchi@icrr.u-tokyo.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto (Japan)
2012-01-01T23:59:59.000Z
We consider a multi-field open inflation model, in which one of the fields dominates quantum tunneling from a false vacuum while the other field governs slow-roll inflation within the bubble nucleated from false vacuum decay. We call the former the tunneling field and the latter the inflaton field. In the limit of a negligible interaction between the two fields, the false vacuum decay is described by a Coleman-De Luccia instanton. Here we take into account the coupling between the two fields and construct explicitly a multi-field instanton for a simple quartic potential model. We also solve the evolution of the scalar fields within the bubble. We find our model realizes open inflation successfully. This is the first concrete, viable model of open inflation realized with a simple potential. We then study the effect of the multi-field dynamics on the false vacuum decay, specifically on the tunneling rate. We find the tunneling rate increases in general provided that the multi-field effect can be treated perturbatively.
Autothermal reforming of gasoline for fuel cell applications : a control-oriented dynamic model.
Hu, Y.; Chmielewski, D. J.; Papadias, D.; Chemical Sciences and Engineering Division; Illinois Inst. of Tech.
2008-11-05T23:59:59.000Z
In this work, we develop a control-oriented, reduced order dynamic model of an autothermal reforming (ATR) reactor. The targeted application is within the on-board fuel-processing unit of a fuel cell vehicle. A previous effort has illustrated that a predictive-type controller may be required to achieve desired performance within this application. The objective of the current effort is to determine the existence of a reduced order model with enough speed and accuracy to meet the online computational demands of a predictive controller. Central to the model development is an approximation of reaction rates that achieve reasonable accuracy near the inlet while preserving the overall energy balance. The resulting scheme converts a partial differential equation model into a set of ordinary differential/algebraic equations and achieves nearly a 4 orders of magnitude improvement in computational speed while preserving most of the nonlinear characteristics of the original system. Such results give clear indication that the hurdle of computational viability can be overcome and opens the door for further development of a predictive controller for the ATR application.
Ilpo Vattulainen; Mikko Karttunen; Gerhard Besold; J. M. Polson
2002-11-15T23:59:59.000Z
We examine the performance of various commonly used integration schemes in dissipative particle dynamics simulations. We consider this issue using three different model systems, which characterize a variety of different conditions often studied in simulations. Specifically we clarify the performance of integration schemes in hybrid models, which combine microscopic and meso-scale descriptions of different particles using both soft and hard interactions. We find that in all three model systems many commonly used integrators may give rise to surprisingly pronounced artifacts in physical observables such as the radial distribution function, the compressibility, and the tracer diffusion coefficient. The artifacts are found to be strongest in systems, where interparticle interactions are soft and predominated by random and dissipative forces, while in systems governed by conservative interactions the artifacts are weaker. Our results suggest that the quality of any integration scheme employed is crucial in all cases where the role of random and dissipative forces is important, including hybrid models where the solvent is described in terms of soft potentials.
W. Schmidt; J. C. Niemeyer; W. Hillebrandt
2006-01-23T23:59:59.000Z
We present a one-equation subgrid scale model that evolves the turbulence energy corresponding to unresolved velocity fluctuations in large eddy simulations. The model is derived in the context of the Germano consistent decomposition of the hydrodynamical equations. The eddy-viscosity closure for the rate of energy transfer from resolved toward subgrid scales is localised by means of a dynamical procedure for the computation of the closure parameter. Therefore, the subgrid scale model applies to arbitrary flow geometry and evolution. For the treatment of microscopic viscous dissipation a semi-statistical approach is used, and the gradient-diffusion hypothesis is adopted for turbulent transport. A priori tests of the localised eddy-viscosity closure and the gradient-diffusion closure are made by analysing data from direct numerical simulations. As an a posteriori testing case, the large eddy simulation of thermonuclear combustion in forced isotropic turbulence is discussed. We intend the formulation of the subgrid scale model in this paper as a basis for more advanced applications in numerical simulations of complex astrophysical phenomena involving turbulence.
History dependent dynamics in a generic model of ion channels - an analytic study
Daniel Soudry; Ron Meir
2010-04-28T23:59:59.000Z
Recent experiments have demonstrated that the timescale of adaptation of single neurons and ion channel populations to stimuli slows down as the length of stimulation increases; in fact, no upper bound on temporal time-scales seems to exist in such systems. Furthermore, patch clamp experiments on single ion channels have hinted at the existence of large, mostly unobservable, inactivation state spaces within a single ion channel. This raises the question of the relation between this multitude of inactivation states and the observed behavior. In this work we propose a minimal model for ion channel dynamics which does not assume any specific structure of the inactivation state space. The model is simple enough to render an analytical study possible. This leads to a clear and concise explanation of the experimentally observed exponential history-dependent relaxation in sodium channels in a voltage clamp setting, and shows that their recovery rate from slow inactivation must be voltage dependent. Furthermore, we predict that history-dependent relaxation cannot be created by overly sparse spiking activity. While the model was created with ion channel populations in mind, its simplicity and genericalness render it a good starting point for modeling similar effects in other systems, and for scaling up to higher levels such as single neurons which are also known to exhibit multiple time scales.
Dynamical Modeling and Multi-Experiment Fitting with PottersWheel Supplement
Timmer, Jens
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3 MATLAB integrators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4 Dynamical
Disks controlling chaos in a 3D dynamical model for elliptical galaxies
Euaggelos E. Zotos
2011-12-05T23:59:59.000Z
A 3D dynamical model with a quasi-homogeneous core and a disk component is used for the chaos control in the central parts of elliptical galaxy. Numerical experiments in the 2D system show a very complicated phase plane with a large chaotic sea, considerable sticky layers and a large number of islands, produced by secondary resonances. When the mass of the disk increases, the chaotic regions decrease gradually, and, finally, a new phase plane with only regular orbits appears. This evolution indicates that disks in elliptical galaxies can act as the chaos controllers. Starting from the results obtained in the 2D system, we locate the regions in the phase space of the 3D system, producing regular and chaotic orbits. For this we introduce and use a new dynamical parameter, the S(w) spectrum, which proves to be useful as a fast indicator and allows us to distinguish the regular motion from chaos in the 3D potentials. Other methods for detecting chaos are also discussed.
Understanding the dynamics of rings in the melt in terms of annealed tree model
Jan Smrek; Alexander Y. Grosberg
2014-09-04T23:59:59.000Z
Dynamical properties of a long polymer ring in a melt of unknotted and unconcatenated rings are calculated. We re-examine and generalize the well known model of a ring confined to a lattice of topological obstacles in the light of the recently developed Flory theory of unentangled rings which maps every ring on an annealed branched polymer and establishes that the backbone associated with each ring follows self-avoiding rather than Gaussian random walk statistics. We find the scaling of ring relaxation time and diffusion coefficient with ring length, as well as time dependence of stress relaxation modulus, zero shear viscosity and mean square averaged displacements of both individual monomers and ring's mass center. Our results agree within error bars with all available experimental and simulations data of the ring melt, although the quality of the data so far is insufficient to make a definitive judgment for or against the annealed tree theory. In the end we review briefly the relation between our findings and experimental data on chromatin dynamics.
Skogestad, Sigurd
of Distillation Columns with Emphasis on the Initial Response BERND WITTGENS and SIGURD SKOGESTAD* Keywords: Distillation dynamics, tray hydraulics, experimental response The flow dynamics (tray hydraulics) are of key importance for the initial dynamic response of distillation columns. The most important parameters
Modeling and Simulation of the Longitudinal Beam Dynamics - RF Station Interaction in the LHC Rings
Mastorides, T; Rivetta, C.; Fox, J.D.; Winkle, D.Van; /SLAC; Baudrenghien, P.; Tuckmantel, J.; /CERN
2008-07-07T23:59:59.000Z
A non-linear time-domain simulation has been developed to study the interaction between longitudinal beam dynamics and RF stations in the LHC rings. The motivation for this tool is to determine optimal LLRF configurations, to study system sensitivity on various parameters, and to define the operational and technology limits. It will be also used to study the effect of RF station noise, impedance, and perturbations on the beam life time and longitudinal emittance. It allows the study of alternative LLRF implementations and control algorithms. The insight and experience gained from our PEP-II simulation is important for this work. In this paper we discuss properties of the simulation tool that will be helpful in analyzing the LHC RF system and its initial results. Partial verification of the model with data taken during the LHC RF station commissioning is presented.
Axisymmetric dynamical models for SAURON and OASIS observations of NGC 3377
Copin, Y; Emsellem, E
2004-01-01T23:59:59.000Z
We present a unique set of nested stellar kinematical maps of NGC 3377 obtained with the integral-field spectrographs OASIS and SAURON. We then construct general axisymmetric dynamical models for this galaxy, based on the Schwarzschild numerical orbit superposition technique applied to these complementary measurements. We show how these two datasets constrain the mass of the central massive object and the overall mass-to-light ratio of the galaxy by probing the inner and outer regions respectively. The simultaneous use of both datasets leads us to confirm the presence of a massive black hole with a mass of $M_{BH} = 7_{-5}^{+4} 10^{7} M_\\sun$ (99.7% confidence level), with a best-fit stellar mass-to-light ratio $\\Upsilon_I = 2.1 \\pm 0.2$ (for an assumed edge-on inclination).
Axisymmetric dynamical models for SAURON and OASIS observations of NGC 3377
Y. Copin; N. Cretton; E. Emsellem
2003-11-18T23:59:59.000Z
We present a unique set of nested stellar kinematical maps of NGC 3377 obtained with the integral-field spectrographs OASIS and SAURON. We then construct general axisymmetric dynamical models for this galaxy, based on the Schwarzschild numerical orbit superposition technique applied to these complementary measurements. We show how these two datasets constrain the mass of the central massive object and the overall mass-to-light ratio of the galaxy by probing the inner and outer regions respectively. The simultaneous use of both datasets leads us to confirm the presence of a massive black hole with a mass of $M_{BH} = 7_{-5}^{+4} 10^{7} M_\\sun$ (99.7% confidence level), with a best-fit stellar mass-to-light ratio $\\Upsilon_I = 2.1 \\pm 0.2$ (for an assumed edge-on inclination).
Light-Front Dynamic Analysis of Bound States in Scalar Field Model
Chueng-Ryong Ji; Yukihisa Tokunaga
2012-05-16T23:59:59.000Z
The light-front dynamics (LFD) of the scalar field model theory is analyzed to solve the two-body bound-state problem. The light-front two-body bound-state equation is extended to the full LFD kernel including the ladder, cross-ladder, stretched-box, and particle-antiparticle creation/annihilation effects to study the contributions of higher Fock-states. The light-front two-body equation is also modified by the term corresponding to the self-energy corrections and counter-terms. Using the variational principle, we obtain the numerical result of the binding energy B versus the coupling constant \\alpha\\ for various mass ratios of the constituent particles including the cases of non-zero exchange particle mass. We also discuss the correlation between the mass spectrum and the corresponding bound-state wavefunction.
Artificial neural networks for input-output dynamic modeling of nonlinear processes
Sarimveis, Haralambos
1992-01-01T23:59:59.000Z
ARTIFICIAL NEURAL NETWORKS FOR INPUT-OUTPUT DYNAMIC MODELING OF NONLINEAR PROCESSES A Th& vis HARALA'&IBOS SARIlcIVEIS Snhnuttect to th&e Otftc& of Cire&11&nt&' Stll&heb of T& x?. Akrr I L'rrrrc& re& tv in pnrtinl frrlfilhrreut of the rc turr...&iveil as to style anel e&a&t& nt hy. 'liM 1 i'll&. hael Nil&a)sou (Chaii of Comuiitte& ) A Teil Watson (I&lenih&a ) Al& ~ii&)e& G. Parloa ( Ileiubei. ) Rayiinai&1 W. F'lumcifelt ( H& a&1 of Defa& it &neat ) A. u ust 10l1a ABSTRACT Artih& ial Neural...
Kaper, Tasso J., E-mail: tasso@bu.edu; Kramer, Mark A., E-mail: mak@bu.edu [Department of Mathematics and Statistics, Boston University, Boston, Massachusetts 02215 (United States); Rotstein, Horacio G., E-mail: horacio@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)
2013-12-15T23:59:59.000Z
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.
Chandrasekhar Potluri,; Madhavi Anugolu; Marco P. Schoen; D. Subbaram Naidu
2013-08-01T23:59:59.000Z
In this work, an array of three surface Electrography (sEMG) sensors are used to acquired muscle extension and contraction signals for 18 healthy test subjects. The skeletal muscle force is estimated using the acquired sEMG signals and a Non-linear Wiener Hammerstein model, relating the two signals in a dynamic fashion. The model is obtained from using System Identification (SI) algorithm. The obtained force models for each sensor are fused using a proposed fuzzy logic concept with the intent to improve the force estimation accuracy and resilience to sensor failure or misalignment. For the fuzzy logic inference system, the sEMG entropy, the relative error, and the correlation of the force signals are considered for defining the membership functions. The proposed fusion algorithm yields an average of 92.49% correlation between the actual force and the overall estimated force output. In addition, the proposed fusionbased approach is implemented on a test platform. Experiments indicate an improvement in finger/hand force estimation.
Merging spatially variant physical process models under an optimized systems dynamics framework.
Cain, William O. (University of Texas at Austin, Austin, TX); Lowry, Thomas Stephen; Pierce, Suzanne A.; Tidwell, Vincent Carroll
2007-10-01T23:59:59.000Z
The complexity of water resource issues, its interconnectedness to other systems, and the involvement of competing stakeholders often overwhelm decision-makers and inhibit the creation of clear management strategies. While a range of modeling tools and procedures exist to address these problems, they tend to be case specific and generally emphasize either a quantitative and overly analytic approach or present a qualitative dialogue-based approach lacking the ability to fully explore consequences of different policy decisions. The integration of these two approaches is needed to drive toward final decisions and engender effective outcomes. Given these limitations, the Computer Assisted Dispute Resolution system (CADRe) was developed to aid in stakeholder inclusive resource planning. This modeling and negotiation system uniquely addresses resource concerns by developing a spatially varying system dynamics model as well as innovative global optimization search techniques to maximize outcomes from participatory dialogues. Ultimately, the core system architecture of CADRe also serves as the cornerstone upon which key scientific innovation and challenges can be addressed.
Computational Model of Population Dynamics Based on the Cell Cycle and Local Interactions
Oprisan, Sorinel Adrian [Department of Psychology, University of New Orleans, 2000 Lakeshore Dr., New Orleans, LA 70148 (United States); Oprisan, Ana [Department of Physics, University of New Orleans, 2000 Lakeshore Dr., New Orleans, LA 70148 (United States)
2005-03-31T23:59:59.000Z
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.
Juven Wang; Jiunn-Wei Chen
2015-01-08T23:59:59.000Z
Fundamental properties of macroscopic gene-mating dynamic evolutionary systems are investigated. A model is proposed to describe a large class of systems within population genetics. We focus on a single locus, arbitrary number alleles in a two-gender dioecious population. Our governing equations are time-dependent continuous differential equations labeled by a set of genotype frequencies. The full parameter space consists of all allowed genotype frequencies. Our equations are uniquely derived from four fundamental assumptions within any population: (1) a closed system; (2) average-and-random mating process (mean-field behavior); (3) Mendelian inheritance; (4) exponential growth and exponential death. Even though our equations are non-linear with time evolutionary dynamics, we have an exactly solvable model. Our findings are summarized from phenomenological and mathematical viewpoints. From the phenomenological viewpoint, any initial genotype frequency of a closed system will eventually approach a stable fixed point. Under time evolution, we show (1) the monotonic behavior of genotype frequencies, (2) any genotype or allele that appears in the population will never become extinct, (3) the Hardy-Weinberg law, and (4) the global stability without chaos in the parameter space. To demonstrate the experimental evidence, as an example, we show a mapping from the blood type genotype frequencies of world ethnic groups to our stable fixed-point solutions. From the mathematical viewpoint, the equilibrium solutions consist of a base manifold as a global stable attractor, attracting any initial point in a Euclidean fiber bundle to the fixed point where the fiber is attached. We can define the genetic distance of two populations as their geodesic distance on the equilibrium manifold. In addition, the modification of our theory under the process of natural selection and mutation is addressed.
Tassis, Konstantinos; Willacy, Karen; Yorke, Harold W.; Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
2012-07-01T23:59:59.000Z
We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores and investigate the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of initial magnetic support, and non-magnetic cores, with varying collapse delay times. We explore, through a parameter study, the competing effects of various model parameters in the evolving molecular abundances, including the elemental C/O ratio, the temperature, and the cosmic-ray ionization rate. We find that different models show their largest quantitative differences at the center of the core, whereas the outer layers, which evolve slower, have abundances which are severely degenerate among different dynamical models. There is a large range of possible abundance values for different models at a fixed evolutionary stage (central density), which demonstrates the large potential of chemical differentiation in prestellar cores. However, degeneracies among different models, compounded with uncertainties induced by other model parameters, make it difficult to discriminate among dynamical models. To address these difficulties, we identify abundance ratios between particular molecules, the measurement of which would have maximal potential for discrimination among the different models examined here. In particular, we find that the ratios between NH{sub 3} and CO, NH{sub 2} and CO, and NH{sub 3} and HCO{sup +} are sensitive to the evolutionary timescale, and that the ratio between HCN and OH is sensitive to the C/O ratio. Finally, we demonstrate that measurements of the central deviation (central depletion or enhancement) of abundances of certain molecules are good indicators of the dynamics of the core.
Treur, Jan
Brazier, F.M.T., Jonker, C.M., and Treur, J., Dynamics and Control in Component-Based Agent Models. This paper addresses specification and semantics of dynamics and control in component-based agent models it is discussed how dynamics and the control of dynamics of processes within an agent are modelled using
Finding Bugs in Web Applications Using Dynamic Test Generation and Explicit State Model Checking
Tip, Frank
2009-03-26T23:59:59.000Z
Web script crashes and malformed dynamically-generated web pages are common errors, and they seriously impact the usability of web applications. Current tools for web-page validation cannot handle the dynamically generated ...
Hewitt, Natalie Case
2012-07-16T23:59:59.000Z
further research. 8 2. METHODS 2.1 Model Design The model is constructed of ordinary differential equations, solved using MatlabTM?s fourth-order Runge-Kutta methods(The Math Works, 2009) and uses a carbon currency to depict two phytoplankton...
K. Nomura; T. Niksic; T. Otsuka; N. Shimizu; D. Vretenar
2011-06-14T23:59:59.000Z
Microscopic energy density functionals (EDF) 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 work we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations, and the Interacting Boson Model. The two models are compared in a study of the evolution of non-axial shapes in Pt isotopes. Starting from the binding energy surfaces of $^{192,194,196}$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-2 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.
Envelope density pattern around wide binary AGB stars: a dynamical model
J. H. He
2007-03-26T23:59:59.000Z
The goal is to build up a simple dynamical model for the out-flowing circumstellar envelope around AGB stars in a wide binary system to explore the parameter dependence of the geometrical characteristics of column density patterns. An AGB star in a wide binary system is considered as a 3-D piston model that can induce a 3-D quasi-spherical density structure in the circumstellar envelope by orbital motion of the AGB star. The column density pattern only depends on two parameters: eccentricity of the orbit e and the terminal outflow velocity to mean orbital velocity ratio gamma. When viewed perpendicular to the orbital plane, spiral, broken spiral, and incomplete concentric shell patterns can be seen, while when viewed along the orbital plane, alternative concentric half-shell, egg-shell, and half-shell half-gap patterns will develop. Non-zero eccentricity causes asymmetry, while larger gamma makes a weaker pattern and helps bring out asymmetry. A spiral pattern may becomes broken when e > 0.4. The spiral center is always less than 12% of spiral pitch away from the orbit center. One should have more chances (~ 80%) seeing spiral-like patterns than seeing concentric shells (~ 20%) in the circumstellar envelope of wide binary AGB stars.
Wind Turbine Modeling for Computational Fluid Dynamics: December 2010 - December 2012
Tossas, L. A. M.; Leonardi, S.
2013-07-01T23:59:59.000Z
With the shortage of fossil fuel and the increasing environmental awareness, wind energy is becoming more and more important. As the market for wind energy grows, wind turbines and wind farms are becoming larger. Current utility-scale turbines extend a significant distance into the atmospheric boundary layer. Therefore, the interaction between the atmospheric boundary layer and the turbines and their wakes needs to be better understood. The turbulent wakes of upstream turbines affect the flow field of the turbines behind them, decreasing power production and increasing mechanical loading. With a better understanding of this type of flow, wind farm developers could plan better-performing, less maintenance-intensive wind farms. Simulating this flow using computational fluid dynamics is one important way to gain a better understanding of wind farm flows. In this study, we compare the performance of actuator disc and actuator line models in producing wind turbine wakes and the wake-turbine interaction between multiple turbines. We also examine parameters that affect the performance of these models, such as grid resolution, the use of a tip-loss correction, and the way in which the turbine force is projected onto the flow field.
William J. Gutowski; Joseph M. Prusa, Piotr K. Smolarkiewicz
2012-04-09T23:59:59.000Z
This project had goals of advancing the performance capabilities of the numerical general circulation model EULAG and using it to produce a fully operational atmospheric global climate model (AGCM) that can employ either static or dynamic grid stretching for targeted phenomena. The resulting AGCM combined EULAG's advanced dynamics core with the 'physics' of the NCAR Community Atmospheric Model (CAM). Effort discussed below shows how we improved model performance and tested both EULAG and the coupled CAM-EULAG in several ways to demonstrate the grid stretching and ability to simulate very well a wide range of scales, that is, multi-scale capability. We leveraged our effort through interaction with an international EULAG community that has collectively developed new features and applications of EULAG, which we exploited for our own work summarized here. Overall, the work contributed to over 40 peer-reviewed publications and over 70 conference/workshop/seminar presentations, many of them invited.
Lee, John D.
2006-01-01T23:59:59.000Z
in which automation recovers from faults. Relevance to industry Promoting cooperation is importantInternational Journal of Industrial Ergonomics 36 (2006) 511526 A dynamic model of interaction between reliance on automation and cooperation in multi-operator multi-automation situations Ji Gaoa
Wang, Wendy
Ecosystem dynamics and export production in the central and eastern equatorial Pacific: A modeling biomass and low export production. Zooplankton and large phytoplankton are more depressed than small enhance export production by a factor of eight in the Nin~o3 area. Large phytoplankton are largely
Stoffel, Markus
Outburst hydrograph s u m m a r y Although moraine dams are inherently prone to failure because and the application of a dynamic dam break model. Results indicate that the moraine failure was caused most probably erosion and finally to dam failure. The lake volume of ca. 10 Â 106 m3 was released in ca. 3 h, producing