Regional Dynamics Model (REDYN) | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia:FAQ < RAPID Jump to: navigation, searchVirginia Blue Ridge And Piedmont Provinces | Open EnergyDynamics Model
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.
Carr, S.S.
1992-01-01T23:59:59.000Z
Limb-scan observations of Doppler line profiles from the (OII) lambda 7320A emission at F-Region altitudes, made with the Fabry-Perot interferometer (FPI) on the Dynamics Explorer-2 (DE-2) spacecraft, have been analyzed to provide measurements of the meridional component of the ion convection velocity along the instrument line-of-sight. The DE-2 results presented here demonstrate the first spaceborne use of the remote-sensing Doppler techniques for measurements of ionospheric convection. The FPI meridional ion drift measurements have been compared with nearly simultaneous in situ ion drift measurements from the Retarding Potential Analyzer (RPA) on DE 2. Once allowance is made for the temporal lag between the in situ and remote measurements, the results from the two techniques are found to be in good agreement, within specified experimental errors, giving confidence in the FPI measurements.
Robertson, A.W.; Ghil, M.; Kravtsov, K.; Smyth, P.J.
2011-04-08T23:59:59.000Z
This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) models for gaining insight into the underlying dynamics in observational data and general circulation model (GCM) simulations. Using coupled O-A ICMs, we have identified a new mechanism of interdecadal climate variability, involving the midlatitude oceans mesoscale eddy field and nonlinear, persistent atmospheric response to the oceanic anomalies. A related decadal mode is also identified, associated with the oceans thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR model developments and software to strengthen two key pillars of support for the development and application of climate models for climate change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from climate models to applications, in order to inform societal adaptation strategies to climate change at the regional scale, including model calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-model ensembles. Our main results from the grant consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling specifically within the non-stationary climate change context together with the development of parallelized software; application of NHMMs to downscaling of rainfall projections over India; identification and analysis of decadal climate signals in data and models; and, studies of climate variability in terms of the dynamics of atmospheric flow regimes. Each of these project components is elaborated on below, followed by a list of publications resulting from the grant.
Kravtsov, S.; Robertson, A. W.; Ghil, M.; Smyth, P. J.
2011-04-08T23:59:59.000Z
This project was a continuation of previous work under DOE CCPP funding in which we developed a twin approach of non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. We have developed a family of latent-variable NHMMs to simulate historical records of daily rainfall, and used them to downscale seasonal predictions. We have also developed empirical mode reduction (EMR) models for gaining insight into the underlying dynamics in observational data and general circulation model (GCM) simulations. Using coupled O-A ICMs, we have identified a new mechanism of interdecadal climate variability, involving the midlatitude oceansâ?? mesoscale eddy field and nonlinear, persistent atmospheric response to the oceanic anomalies. A related decadal mode is also identified, associated with the oceansâ?? thermohaline circulation. The goal of the continuation was to build on these ICM results and NHMM/EMR model developments and software to strengthen two key pillars of support for the development and application of climate models for climate change projections on time scales of decades to centuries, namely: (a) dynamical and theoretical understanding of decadal-to-interdecadal oscillations and their predictability; and (b) an interface from climate models to applications, in order to inform societal adaptation strategies to climate change at the regional scale, including model calibration, correction, downscaling and, most importantly, assessment and interpretation of spread and uncertainties in multi-model ensembles. Our main results from the grant consist of extensive further development of the hidden Markov models for rainfall simulation and downscaling specifically within the non-stationary climate change context together with the development of parallelized software; application of NHMMs to downscaling of rainfall projections over India; identification and analysis of decadal climate signals in data and models; and, studies of climate variability in terms of the dynamics of atmospheric flow regimes. Each of these project components is elaborated on below, followed by a list of publications resulting from the grant.
Forest dynamics at regional scales: predictive models constrained with inventory data
Lines, Emily
2012-06-12T23:59:59.000Z
by scaling from key tree-level processes, but models typically have no climate dependency. In this thesis I demonstrate how large-scale national inventories combined with improvements in computational methods mean that models that incorporate the climate...
Dynamical Coupled-Channel Model of pi-N scattering in te W < 2 GeV Nucleon Resonane Region
T.S.H. Lee; B. Julia-diaz; A. Matsuyama; T. Sato
2007-12-01T23:59:59.000Z
As a first step to analyze the electromagnetic meson production reactions in the nucleon resonance region, the parameters of the hadronic interactions of a dynamical coupled-channel model, developed in {\\it Physics Reports 439, 193 (2007)}, are determined by fitting the empirical $\\pi N$ elastic scattering amplitudes of SAID up to 2 GeV. The channels included in the calculations are $\\pi N$, $\\eta N$ and $\\pi\\pi N$ which has $\\pi\\Delta$, $\\rho N$, and $\\sigma N$ resonant components. The non-resonant meson-baryon interactions of the model are derived from a set of Lagrangians by using a unitary transformation method. One or two bare excited nucleon states in each of $S$, $P$, $D$, and $F$ partial waves are included to generate the resonant amplitudes in the fits. The predicted total cross sections of $\\pi N$ reactions and $\\pi N\\rightarrow \\eta N$ reactions are in good agreement with the data. Applications of the constructed model in analyzing the electromagnetic meson production data as well as the future developments are discussed.
Modeling the Dynamics of Desakota Regions: Global - Local Nexus in the Taipei Metropolitan Area
Wu, Bing-Sheng
2010-10-12T23:59:59.000Z
Since the 1970s, Asia has experienced rapid urbanization processes, which are distinct from U.S. society, and the direction of Asian urbanization is more strongly affected by economic globalization. The desakota model, proposed by McGee and Ginsburg...
Matyushov, Dmitry
A phenomenological model of dynamical arrest of electron transfer in solvents in the glass 2004; published online 17 February 2005 A phenomenological model of electron transfer reactions-acceptor energy gaps dashed line in Fig. 1 differs from the equilibrium distribution. The present phenomenological
Recovery of Dynamic PET Regions via Simultaneous Segmentation and Deconvolution
MÃ¶ller, Torsten
Recovery of Dynamic PET Regions via Simultaneous Segmentation and Deconvolution Benjamin Smith1 and deconvolution of dynamic PET images. By incorporating the PSF of the imaging system into our segmentation model effect. We show improved segmentation results, and outperform two state-of-the-art dynamic PET
Queuing models System dynamics models
Glushko, Robert J.
models Value chain models Business Model / Organizational Perspective Process Perspective Information#12;#12;#12;#12;Queuing models System dynamics models #12;#12;#12;#12;Blueprint or touchpoint
Modal aerosol dynamics modeling
Whitby, E.R.; McMurry, P.H.; Shankar, U.; Binkowski, F.S.
1991-02-01T23:59:59.000Z
The report presents the governing equations for representing aerosol dynamics, based on several different representations of the aerosol size distribution. Analytical and numerical solution techniques for these governing equations are also reviewed. Described in detail is a computationally efficient numerical technique for simulating aerosol behavior in systems undergoing simultaneous heat transfer, fluid flow, and mass transfer in and between the gas and condensed phases. The technique belongs to a general class of models known as modal aerosol dynamics (MAD) models. These models solve for the temporal and spatial evolution of the particle size distribution function. Computational efficiency is achieved by representing the complete aerosol population as a sum of additive overlapping populations (modes), and solving for the time rate of change of integral moments of each mode. Applications of MAD models for simulating aerosol dynamics in continuous stirred tank aerosol reactors and flow aerosol reactors are provided. For the application to flow aerosol reactors, the discussion is developed in terms of considerations for merging a MAD model with the SIMPLER routine described by Patankar (1980). Considerations for incorporating a MAD model into the U.S. Environmental Protection Agency's Regional Particulate Model are also described. Numerical and analytical techniques for evaluating the size-space integrals of the modal dynamics equations (MDEs) are described. For multimodal logonormal distributions, an analytical expression for the coagulation integrals of the MDEs, applicable for all size regimes, is derived, and is within 20% of accurate numerical evaluation of the same moment coagulation integrals. A computationally efficient integration technique, based on Gauss-Hermite numerical integration, is also derived.
Smyth, Padhraic [University of California, Irvine
2013-07-22T23:59:59.000Z
This is the final report for a DOE-funded research project describing the outcome of research on non-homogeneous hidden Markov models (NHMMs) and coupled ocean-atmosphere (O-A) intermediate-complexity models (ICMs) to identify the potentially predictable modes of climate variability, and to investigate their impacts on the regional-scale. The main results consist of extensive development of the hidden Markov models for rainfall simulation and downscaling specifically within the non-stationary climate change context together with the development of parallelized software; application of NHMMs to downscaling of rainfall projections over India; identification and analysis of decadal climate signals in data and models; and, studies of climate variability in terms of the dynamics of atmospheric flow regimes.
Regional Climate Modeling: Progress, Challenges, and Prospects
Wang, Yuqing; Leung, Lai R.; McGregor, John L.; Lee, Dong-Kyou; Wang, Wei-Chyung; Ding, Yihui; Kimura, Fujio
2004-12-01T23:59:59.000Z
Regional climate modeling with regional climate models (RCMs) has matured over the past decade and allows for meaningful utilization in a broad spectrum of applications. In this paper, latest progresses in regional climate modeling studies are reviewed, including RCM development, applications of RCMs to dynamical downscaling for climate change assessment, seasonal climate predictions and climate process studies, and the study of regional climate predictability. Challenges and potential directions of future research in this important area are discussed, with the focus on those to which less attention has been given previously, such as the importance of ensemble simulations, further development and improvement of regional climate modeling approach, modeling extreme climate events and sub-daily variation of clouds and precipitation, model evaluation and diagnostics, applications of RCMs to climate process studies and seasonal predictions, and development of regional earth system models. It is believed that with both the demonstrated credibility of RCMs’ capability in reproducing not only monthly to seasonal mean climate and interannual variability but also the extreme climate events when driven by good quality reanalysis and the continuous improvements in the skill of global general circulation models (GCMs) in simulating large-scale atmospheric circulation, regional climate modeling will remain an important dynamical downscaling tool for providing the needed information for assessing climate change impacts and seasonal climate predictions, and a powerful tool for improving our understanding of regional climate processes. An internationally coordinated effort can be developed with different focuses by different groups to advance regional climate modeling studies. It is also recognized that since the final quality of the results from nested RCMs depends in part on the realism of the large-scale forcing provided by GCMs, the reduction of errors and improvement in physics parameterizations in both GCMs and RCMs remain a priority for climate modeling community.
Models of Dynamical Supersymmetry Breaking
Lisa Randall
1997-06-23T23:59:59.000Z
We review a class of models of dynamical supersymmetry breaking, and give a unified description of these models.
Dynamic Modelling, Measurement and
Fernandez, Thomas
Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders Justin Rae Elsey, B;Summary Co-rotating twin-screw extruders are unique and versatile machines that are used widely that these extruders are currently being optimally utilised. The most signi cant improvement to the eld of twin-screw
High order hybrid discontinuous Galerkin regional ocean modelling
Ueckermann, Mattheus Percy
2014-01-01T23:59:59.000Z
Accurate modeling of physical and biogeochemical dynamics in coastal ocean regions is required for multiple scientific and societal applications, covering a wide range of time and space scales. However, in light of the ...
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 ...
GLOBAL DYNAMICS OF SUBSURFACE SOLAR ACTIVE REGIONS
Jouve, L. [UPS-OMP, Institut de Recherche en Astrophysique et Planetologie, Universite de Toulouse CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse (France)] [UPS-OMP, Institut de Recherche en Astrophysique et Planetologie, Universite de Toulouse CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse (France); Brun, A. S. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/SAp, F-91191 Gif sur Yvette (France)] [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/SAp, F-91191 Gif sur Yvette (France); Aulanier, G., E-mail: ljouve@irap.omp.eu [LESIA, Observatoire de Paris, CNRS, UPMC, Universite Paris-Diderot, 5 Place Jules Janssen, F-92190 Meudon Cedex (France)
2013-01-01T23:59:59.000Z
We present three-dimensional numerical simulations of a magnetic loop evolving in either a convectively stable or unstable rotating shell. The magnetic loop is introduced into the shell in such a way that it is buoyant only in a certain portion in longitude, thus creating an {Omega}-loop. Due to the action of magnetic buoyancy, the loop rises and develops asymmetries between its leading and following legs, creating emerging bipolar regions whose characteristics are similar to those of observed spots at the solar surface. In particular, we self-consistently reproduce the creation of tongues around the spot polarities, which can be strongly affected by convection. We further emphasize the presence of ring-shaped magnetic structures around our simulated emerging regions, which we call 'magnetic necklace' and which were seen in a number of observations without being reported as of today. We show that those necklaces are markers of vorticity generation at the periphery and below the rising magnetic loop. We also find that the asymmetry between the two legs of the loop is crucially dependent on the initial magnetic field strength. The tilt angle of the emerging regions is also studied in the stable and unstable cases and seems to be affected both by the convective motions and the presence of a differential rotation in the convective cases.
Regions in Energy Market Models
Short, W.
2007-02-01T23:59:59.000Z
This report explores the different options for spatial resolution of an energy market model--and the advantages and disadvantages of models with fine spatial resolution. It examines different options for capturing spatial variations, considers the tradeoffs between them, and presents a few examples from one particular model that has been run at different levels of spatial resolution.
THE DYNAMICS AND HEATING OF ACTIVE REGION LOOPS
Doschek, G. A., E-mail: george.doschek@nrl.navy.mil [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
2012-08-01T23:59:59.000Z
I examine the dynamics of active regions using spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. I show the relationship between non-thermal velocities, Doppler outflows and downflows, intensities, and electron density for two representative active regions out of a group of 18 active regions examined. Results from the other active regions are summarized. Imaging spectra of these active regions were obtained from a number of different EIS raster observations. In the case of the outflows for the two representative regions, two-Gaussian fits were made to line profiles of Fe XII and Fe XIII to obtain quantitative information on high-speed components of the outflows. A three-Gaussian fit was made for the Fe XII line at {lambda}195.119. The highest speed outflows occur in weak regions adjacent to the bright loops in active regions. They are weak (less than 5% of the intensity of the main spectral component in the brightest parts of active regions) and even in the extensive flow regions they are generally less than 25% of the intensity of the main component. The outflow regions are characterized by long or open magnetic field lines and I suggest that the apparent absence of these higher speed outflows in bright regions is due to abundant stationary plasma in the closed bright loop regions that mask or overwhelm the outflow signal.
Modeling Molecular Dynamics from Simulations
Hinrichs, Nina Singhal (University of Chicago) [University of Chicago
2009-01-28T23:59:59.000Z
Many important processes in biology occur at the molecular scale. A detailed understanding of these processes can lead to significant advances in the medical and life sciences. For example, many diseases are caused by protein aggregation or misfolding. One approach to studying these systems is to use physically-based computational simulations to model the interactions and movement of the molecules. While molecular simulations are computationally expensive, it is now possible to simulate many independent molecular dynamics trajectories in a parallel fashion by using super- or distributed- computing methods such as Folding@Home or Blue Gene. The analysis of these large, high-dimensional data sets presents new computational challenges. In this seminar, I will discuss a novel approach to analyzing large ensembles of molecular dynamics trajectories to generate a compact model of the dynamics. This model groups conformations into discrete states and describes the dynamics as Markovian, or history-independent, transitions between the states. I will discuss why the Markovian state model (MSM) is suitable for macromolecular dynamics, and how it can be used to answer many interesting and relevant questions about the molecular system. I will also discuss many of the computational and statistical challenges in building such a model, such as how to appropriately cluster conformations, determine the statistical reliability, and efficiently design new simulations.
RESEARCH ARTICLE Modelling multi-species response to landscape dynamics
Kleyer, Michael
and to the spatio-temporal configuration of urban brownfield habitats in a multi-species approach (37 plant and 43- sion time of brownfield habitats required to support all and especially regionally rare species Dynamic landscape Ã Species distribution model Ã Habitat model Ã Urban brownfields Ã Model averaging Ã
Unbounded dynamics in dissipative flows: Rössler model
Barrio, Roberto, E-mail: rbarrio@unizar.es; Serrano, Sergio, E-mail: sserrano@unizar.es [Computational Dynamics Group, Dpto. Matemática Aplicada and IUMA, Universidad de Zaragoza, E-50009 Zaragoza (Spain)] [Computational Dynamics Group, Dpto. Matemática Aplicada and IUMA, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Blesa, Fernando, E-mail: fblesa@unizar.es [Computational Dynamics Group, Dpto. Física Aplicada and IUMA, Universidad de Zaragoza, E-50009 Zaragoza (Spain)] [Computational Dynamics Group, Dpto. Física Aplicada and IUMA, Universidad de Zaragoza, E-50009 Zaragoza (Spain)
2014-06-15T23:59:59.000Z
Transient chaos and unbounded dynamics are two outstanding phenomena that dominate in chaotic systems with large regions of positive and negative divergences. Here, we investigate the mechanism that leads the unbounded dynamics to be the dominant behavior in a dissipative flow. We describe in detail the particular case of boundary crisis related to the generation of unbounded dynamics. The mechanism of the creation of this crisis in flows is related to the existence of an unstable focus-node (or a saddle-focus) equilibrium point and the crossing of a chaotic invariant set of the system with the weak-(un)stable manifold of the equilibrium point. This behavior is illustrated in the well-known Rössler model. The numerical analysis of the system combines different techniques as chaos indicators, the numerical computation of the bounded regions, and bifurcation analysis. For large values of the parameters, the system is studied by means of Fenichel's theory, providing formulas for computing the slow manifold which influences the evolution of the first stages of the orbit.
A Relativistic Dynamical Collapse Model
Philip Pearle
2014-12-21T23:59:59.000Z
A model is discussed where all operators are constructed from a quantum scalar field whose energy spectrum takes on all real values. The Schr\\"odinger picture wave function depends upon space and time coordinates for each particle, as well as an inexorably increasing evolution parameter $s$ which labels a foliation of space-like hypersurfaces. The model is constructed to be manifestly Lorentz invariant in the interaction picture. Free particle states and interactions are discussed in this framework. Then, the formalism of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied. The collapse-generating operator is chosen to to be the particle number space-time density. Unlike previous relativistically invariant models, the vacuum state is not excited. The collapse dynamics depends upon two parameters, a parameter $\\Lambda$ which represents the collapse rate/volume and a scale factor $\\ell$. A common example of collapse dynamics, involving a clump of matter in a superposition of two locations, is analyzed. The collapse rate is shown to be identical to that of non-relativistic CSL when the GRW-CSL choice of $\\ell=a=10^{-5}$cm, is made, along with $\\Lambda=\\lambda/a^{3}$ (GRW-CSL choice $\\lambda=10^{-16}s^{-1}$). However, it is also shown that the change of mass of a nucleon over the age of the universe is then unacceptably large. The case where $\\ell$ is the size of the universe is then considered. It is shown that the collapse behavior is satisfactory and the change of mass over the age of the universe is acceptably small, when $\\Lambda= \\lambda/\\ell a^{2}$.
Does High[Plasma]-Beta Dynamics "Load" Active Regions?
Scott W. McIntosh
2007-02-04T23:59:59.000Z
Using long-duration observations in the He II 304 Angstrom passband of the Solar and Heliospheric Observatory (SOHO) Extreme-ultraviolet Imaging Telescope (EIT) we investigate the spatial and temporal appearance of impulsive intensity fluctuations in the pixel light curves. These passband intensity fluctuations come from plasma emitting in the chromosphere, transition region and lowest portions of the corona. We see that they are spatially tied to the supergranular scale and that their rate of occurrence is tied to the unsigned imbalance of the magnetic field in which they are observed. The signature of the fluctuations (in space and time) is consistent with their creation by magnetoconvection forced reconnection that is driven by the flow field in the high-beta plasma. The signature of the intensity fluctuations around an active region suggest that the bulk of the mass and energy supplied into the active region complex observed in the hotter coronal plasma is supplied by this process, dynamically forcing the looped structure from beneath.
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
Modeling-Computer Simulations At Nw Basin & Range Region (Biasi...
Location Northwest Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness useful regional reconnaissance DOE-funding...
Impact of the solar wind dynamic pressure on the Region 2 field-aligned currents
Higuchi, Tomoyuki
Impact of the solar wind dynamic pressure on the Region 2 field-aligned currents S. Nakano,1,2 G and the solar wind dynamic pressure is investigated using magnetic field data from Defense Meteorological in the magnetosphere varies with the solar wind dynamic pressure. Therefore, we can expect that the Region 2 currents
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...
Model Validation with Hybrid Dynamic Simulation
Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.
2006-06-18T23:59:59.000Z
Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation.
Calcium Dynamics in Large Neuronal Models
De Schutter, Erik
Chapter 6 Calcium Dynamics in Large Neuronal Models ERIK DE SCHUTTER and PAUL SMOLEN 6.1 Introduction Calcium is an important intracellular signaling molecule with rapid e ect on the kinetics of many active membrane model that includes Ca2+ dynamics, one is faced with a feedback loop: the Ca2+-activated
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.
Adjoint modeling for atmospheric pollution process sensitivity at regional scale
Menut, Laurent
Adjoint modeling for atmospheric pollution process sensitivity at regional scale Laurent Menut; 0345 Atmospheric Composition and Structure: Pollution--urban and regional (0305); 3210 Mathematical: atmospheric pollution, tropospheric ozone, urban pollution peaks, adjoint modeling, sensitivity Citation
Very Large System Dynamics Models - Lessons Learned
Jacob J. Jacobson; Leonard Malczynski
2008-10-01T23:59:59.000Z
This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.
Dynamics Modelling of Biolistic Gene Guns
Zhang, M.; Tao, W.; Pianetta, P.A.
2009-06-04T23:59:59.000Z
The gene transfer process using biolistic gene guns is a highly dynamic process. To achieve good performance, the process needs to be well understood and controlled. Unfortunately, no dynamic model is available in the open literature for analysing and controlling the process. This paper proposes such a model. Relationships of the penetration depth with the helium pressure, the penetration depth with the acceleration distance, and the penetration depth with the micro-carrier radius are presented. Simulations have also been conducted. The results agree well with experimental results in the open literature. The contribution of this paper includes a dynamic model for improving and manipulating performance of the biolistic gene gun.
DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL
Mease, Kenneth D.
DYNAMIC MODELING PROTON EXCHANGE MEMBRANE FUEL CELL OVERVIEW Current/Completed Plug Power reformer from GE · Use of GenCore to investigate effects of fuel quality and dynamic changes in fuel to garner SCAQMD funding for fuel cell testing GenCore system is sensitive to diluents · As built design
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.
Modeling Dynamics of Post Disaster Recovery
Nejat, Ali
2012-10-19T23:59:59.000Z
Subject: Civil Engineering iii ABSTRACT Modeling Dynamics of Post Disaster Recovery. (August 2011) Ali Nejat, B.S., Zanjan University, Zanjan, Iran; M.S., Islamic Azad University, Tehran, Iran Chair of Advisory Committee: Dr. Ivan Damnjanovic... MODELING DYNAMICS OF POST DISASTER RECOVERY A Dissertation by ALI NEJAT Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY...
Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region
Aluffi, Paolo
Diamond Lattice Model of Semicrystalline Polyethylene in the Amorphous Region ZhongÂHui Duan Abstract The statistics of polyethylene chains in the amorphous region between two crystallites have been as models of the chain molecules in the amorphous region of semicrystalline polyethylene, both
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.
Model Validation with Hybrid Dynamic Simulation
Huang, Zhenyu; Kosterev, Dmitry; Guttromson, Ross T.; Nguyen, Tony B.
2006-06-22T23:59:59.000Z
Abstract—Model validation has been one of the central topics in power engineering studies for years. As model validation aims at obtaining reasonable models to represent actual behavior of power system components, it has been essential to validate models against actual measurements or known benchmark behavior. System-wide model simulation results can be compared with actual recordings. However, it is difficult to construct a simulation case for a large power system such as the WECC system and to narrow down to problematic models in a large system. Hybrid dynamic simulation with its capability of injecting external signals into dynamic simulation enables rigorous comparison of measurements and simulation in a small subsystem of interest. This paper presents such a model validation methodology with hybrid dynamic simulation. Two application examples on generator and load model validation are presented to show the validity of this model validation methodology. This methodology is further extended for automatic model validation and dichotomous subsystem model validation. A few methods to define model quality indices have been proposed to quantify model error for model validation criteria development.
Wei, Jun
Climatological high resolution coupled climate model simulations for the maritime continent have been carried out using the regional climate model (RegCM) version 3 and the finite volume coastal ocean model (FVCOM) ...
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.
Human Muscle Fatigue Model in Dynamic Motions
Boyer, Edmond
Human Muscle Fatigue Model in Dynamic Motions Ruina Ma, Damien Chablat, Fouad Bennis, and Liang Ma Abstract Human muscle fatigue is considered to be one of the main reasons for Musculoskeletal Disorder (MSD). Recent models have been introduced to define muscle fatigue for static postures. However, the main
Modeling dynamic swarms q Bernard Ghanem a,
Ahuja, Narendra
a c t This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define of our method by conducting experiments on real and synthetic video sequences. Real sequences of birds Elsevier Inc. All rights reserved. 1. Introduction This paper is about modeling video sequences of a dense
Modeling-Computer Simulations At Northern Basin & Range Region...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Northern Basin & Range Region (Biasi, Et Al., 2009) Exploration...
Modeling-Computer Simulations At Northern Basin & Range Region...
Northern Basin and Range Geothermal Region Exploration Technique Modeling-Computer Simulations Activity Date Usefulness not indicated DOE-funding Unknown References J. W. Pritchett...
Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett...
navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Modeling-Computer Simulations At Nw Basin & Range Region (Pritchett, 2004) Exploration Activity Details...
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 System Analysis for a phantom model
Nilanjana Mahata; Subenoy Chakraborty
2014-04-24T23:59:59.000Z
The paper deals with a dynamical system analysis related to phantom cosmological model . Here gravity is coupled to phantom scalar field having scalar coupling function and a potential. The field equations are reduced to an autonomous dynamical system by a suitable redefinition of the basic variables and assuming some suitable form of the potential function. Finally, critical points are evaluated, their nature have been analyzed and corresponding cosmological scenario has been discussed.
The WAMME regional model intercomparison study
2010-01-01T23:59:59.000Z
has produced a multi-model climatology of land surface ?uxesThe Global Precipitation Climatology Project (GPCP) combined
Modeling emotional dynamics : currency versus field.
Sallach, D .L.; Decision and Information Sciences; Univ. of Chicago
2008-08-01T23:59:59.000Z
Randall Collins has introduced a simplified model of emotional dynamics in which emotional energy, heightened and focused by interaction rituals, serves as a common denominator for social exchange: a generic form of currency, except that it is active in a far broader range of social transactions. While the scope of this theory is attractive, the specifics of the model remain unconvincing. After a critical assessment of the currency theory of emotion, a field model of emotion is introduced that adds expressiveness by locating emotional valence within its cognitive context, thereby creating an integrated orientation field. The result is a model which claims less in the way of motivational specificity, but is more satisfactory in modeling the dynamic interaction between cognitive and emotional orientations at both individual and social levels.
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.
Modeling the Dynamics of Fermentation and Respiratory
Sheffield, University of
, denitrification, and SO4-reduction). The accumulation of acetate as a fermentation product within the plume species, e.g., H2(aq) or acetate, followed by respiration by other groups of organisms where fermentationModeling the Dynamics of Fermentation and Respiratory Processes in a Groundwater Plume of Phenolic
Modeling joint friction in structural dynamics.
Segalman, Daniel Joseph
2005-05-01T23:59:59.000Z
The presence of mechanical joints--typified by the lap joint--in otherwise linear structures has been accommodated in structural dynamics via ad hoc methods for a century. The methods range from tuning linear models to approximate non-linear behavior in restricted load ranges to various methods which introduce joint dissipation in a post-processing stage. Other methods, employing constitutive models for the joints are being developed and their routine use is on the horizon.
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.
Spatial Models for Groundwater Behavioral Analysis in Regions of Maharashtra
Sohoni, Milind
Spatial Models for Groundwater Behavioral Analysis in Regions of Maharashtra M.Tech Dissertation on groundwater and classified the years into good year if water levels are above the seasonal model in that year such as land-use, local hydrogeology. #12;Contents 1 Introduction 1 1.1 Spatial Models
Structural system identification: Structural dynamics model validation
Red-Horse, J.R.
1997-04-01T23:59:59.000Z
Structural system identification is concerned with the development of systematic procedures and tools for developing predictive analytical models based on a physical structure`s dynamic response characteristics. It is a multidisciplinary process that involves the ability (1) to define high fidelity physics-based analysis models, (2) to acquire accurate test-derived information for physical specimens using diagnostic experiments, (3) to validate the numerical simulation model by reconciling differences that inevitably exist between the analysis model and the experimental data, and (4) to quantify uncertainties in the final system models and subsequent numerical simulations. The goal of this project was to develop structural system identification techniques and software suitable for both research and production applications in code and model validation.
Scenario Evaluation and Regionalization Analysis (SERA) Model
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up from the Gridwise Global Forum Round-UpSTATEof EnergyScale Models andUniversity
Method of evaluating, expanding, and collapsing connectivity regions within dynamic systems
Bailey, David A. (Schenectady, NY)
2004-11-16T23:59:59.000Z
An automated process defines and maintains connectivity regions within a dynamic network. The automated process requires an initial input of a network component around which a connectivity region will be defined. The process automatically and autonomously generates a region around the initial input, stores the region's definition, and monitors the network for a change. Upon detecting a change in the network, the effect is evaluated, and if necessary the regions are adjusted and redefined to accommodate the change. Only those regions of the network affected by the change will be updated. This process eliminates the need for an operator to manually evaluate connectivity regions within a network. Since the automated process maintains the network, the reliance on an operator is minimized; thus, reducing the potential for operator error. This combination of region maintenance and reduced operator reliance, results in a reduction of overall error.
A Framework for Modeling Uncertainty in Regional Climate Change
Monier, Erwan
In this study, we present a new modeling framework and a large ensemble of climate projections to investigate the uncertainty in regional climate change over the US associated with four dimensions of uncertainty. The sources ...
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.
DYNAMICAL MODELING OF GALAXY MERGERS USING IDENTIKIT
Privon, G. C.; Evans, A. S. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Barnes, J. E. [Institute for Astronomy, University of Hawaii, at Manoa, Honolulu, HI (United States); Hibbard, J. E. [National Radio Astronomy Observatory, Charlottesville, VA 22904 (United States); Yun, M. S. [Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States); Mazzarella, J. M. [NASA Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Armus, L.; Surace, J., E-mail: gcp8y@virginia.edu [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)
2013-07-10T23:59:59.000Z
We present dynamical models of four interacting systems: NGC 5257/8, The Mice, the Antennae, and NGC 2623. The parameter space of the encounters are constrained using the Identikit model-matching and visualization tool. Identikit utilizes hybrid N-body and test particle simulations to enable rapid exploration of the parameter space of galaxy mergers. The Identikit-derived matches of these systems are reproduced with self-consistent collisionless simulations which show very similar results. The models generally reproduce the observed morphology and H I kinematics of the tidal tails in these systems with reasonable properties inferred for the progenitor galaxies. The models presented here are the first to appear in the literature for NGC 5257/8 and NGC 2623, and The Mice and the Antennae are compared with previously published models. Based on the assumed mass model and our derived initial conditions, the models indicate that the four systems are currently being viewed 175-260 Myr after first passage and cover a wide range of merger stages. In some instances there are mismatches between the models and the data (e.g., in the length of a tail); these are likely due to our adoption of a single mass model for all galaxies. Despite the use of a single mass model, these results demonstrate the utility of Identikit in constraining the parameter space for galaxy mergers when applied to real data.
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 ...
RSL: A parallel Runtime System Library for regional atmospheric models with nesting
Michalakes, J.G.
1997-08-01T23:59:59.000Z
RSL is a parallel runtime system library developed at Argonne National Laboratory that is tailored to regular-grid atmospheric models with mesh refinement in the form of two-way interacting nested grids. RSL provides high-level stencil and interdomain communication, irregular domain decomposition, automatic local/global index translation, distributed I/O, and dynamic load balancing. RSL was used with Fortran90 to parallelize a well-known and widely used regional weather model, the Penn State/NCAR Mesoscale model.
Dynamical Models for the Milky Way
Walter Dehnen; James Binney
1996-01-10T23:59:59.000Z
The only way to map the Galaxy's gravitational potential $\\Phi({\\bf x})$ and the distribution of matter that produces it is by modelling the dynamics of stars and gas. Observations of the kinematics of gas provide key information about gradients of $\\Phi$ within the plane, but little information about the structure of $\\Phi$ out of the plane. Traditional Galaxy models {\\em assume}, for each of the Galaxy's components, arbitrary flattenings, which together with the components' relative masses yield the model's equipotentials. However, the Galaxy's isopotential surfaces should be {\\em determined\\/} directly from the motions of stars that move far from the plane. Moreover, from the kinematics of samples of such stars that have well defined selection criteria, one should be able not only to map $\\Phi$ at all positions, but to determine the distribution function $f_i({\\bf x},{\\bf v})$ of each stellar population $i$ studied. These distribution functions will contain a wealth of information relevant to the formation and evolution of the Galaxy. An approach to fitting a wide class of dynamical models to the very heterogeneous body of available data is described and illustrated.
Regional Climate Model Projections for the State of Washington
Salathe, E.; Leung, Lai-Yung R.; Qian, Yun; Zhang, Yongxin
2010-05-05T23:59:59.000Z
Global climate models do not have sufficient spatial resolution to represent the atmospheric and land surface processes that determine the unique regional heterogeneity of the climate of the State of Washington. If future large-scale weather patterns interact differently with the local terrain and coastlines than current weather patterns, local changes in temperature and precipitation could be quite different from the coarse-scale changes projected by global models. Regional climate models explicitly simulate the interactions between the large-scale weather patterns simulated by a global model and the local terrain. We have performed two 100-year climate simulations using the Weather and Research Forecasting (WRF) model developed at the National Center for Atmospheric Research (NCAR). One simulation is forced by the NCAR Community Climate System Model version 3 (CCSM3) and the second is forced by a simulation of the Max Plank Institute, Hamburg, global model (ECHAM5). The mesoscale simulations produce regional changes in snow cover, cloudiness, and circulation patterns associated with interactions between the large-scale climate change and the regional topography and land-water contrasts. These changes substantially alter the temperature and precipitation trends over the region relative to the global model result or statistical downscaling. To illustrate this effect, we analyze the changes from the current climate (1970-1999) to the mid 21st century (2030-2059). Changes in seasonal-mean temperature, precipitation, and snowpack are presented. Several climatological indices of extreme daily weather are also presented: precipitation intensity, fraction of precipitation occurring in extreme daily events, heat wave frequency, growing season length, and frequency of warm nights. Despite somewhat different changes in seasonal precipitation and temperature from the two regional simulations, consistent results for changes in snowpack and extreme precipitation are found in both simulations.
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 on the protection of the African elephant (Laxadonta africana). The model consists of four ivory exporting regions
MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL
Rossiter, D G "David"
MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL David G. Rossiter of Agronomy, Inc. #12;MODELING PLANT COMPETITION WITH THE GAPS OBJECT-ORIENTED DYNAMIC SIMULATION MODEL Abstract Modeling inter-species competition is a natural application for dynamic simulation models
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.
ONGOING RESEARCH PROJECTS Model of tropical forest structure and dynamics
Hill, Jeffrey E.
ONGOING RESEARCH PROJECTS Model of tropical forest structure and dynamics There is a need canopy structure and partitions dynamic rates for a tropical forest on Barro Colorado Island (BCI structure and partitions dynamic rates in a tropical forest. In Review. Journal of Ecology. #12;PPA model
Analysis of Photoreaction in the Delta Energy Region by the Quantum Molecular Dynamics Approach
Tomoyuki Maruyama; Koji Niita; Satoshi Chiba; Toshiki Maruyama; Akira Iwamoto
1997-05-02T23:59:59.000Z
We study the photoreaction in the delta energy region using the QMD approach. The proton and pion cross-sections are calculated and compared with experimental data. Through this work we examine the multistep contributions in the cross-sections and the {$\\pi - \\Delta$} dynamics.
A Dynamical IS-LM Model Allen Tang
Marzuola, Jeremy
A Dynamical IS-LM Model Allen Tang The University of North Carolina the specifications of a discrete dynamical IS-LM model and discuss how this model can of monetary policy, to an economy. The standard static IS-LM model arises
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
A lattice mesoscopic model of dynamically heterogeneous fluids
A. Lamura; S. Succi
2005-10-04T23:59:59.000Z
We introduce a mesoscopic three-dimensional Lattice Boltzmann Model which attempts to mimick the physical features associated with cage effects in dynamically heterogeneous fluids. To this purpose, we extend the standard Lattice Boltzmann dynamics with self-consistent constraints based on the non-local density of the surrounding fluid. The resulting dynamics exhibits typical features of dynamic heterogeneous fluids, such as non-Gaussian density distributions and long-time relaxation. Due to its intrinsically parallel dynamics, and absence of statistical noise, the method is expected to compute significantly faster than molecular dynamics, Monte Carlo and lattice glass models.
THE DEVELOPMENT MODEL ELECTRONIC COMMERCE OF REGIONAL AGRICULTURE
Boyer, Edmond
THE DEVELOPMENT MODEL ELECTRONIC COMMERCE OF REGIONAL AGRICULTURE Jun Kang* , Lecai Cai, Hongchan, Fax: +86-813-5505966, Email: kj_sky@126.com Abstract: With the developing of the agricultural information, it is inevitable trend of the development of agricultural electronic commercial affairs
Reference wind farm selection for regional wind power prediction models
Paris-Sud XI, UniversitÃ© de
1 Reference wind farm selection for regional wind power prediction models Nils Siebert George.siebert@ensmp.fr, georges.kariniotakis@ensmp.fr Abstract Short-term wind power forecasting is recognized today as a major requirement for a secure and economic integration of wind generation in power systems. This paper deals
Modeling-Computer Simulations At U.S. West Region (Williams ...
Modeling-Computer Simulations At U.S. West Region (Williams & Deangelo, 2008) Exploration Activity Details Location U.S. West Region Exploration Technique Modeling-Computer...
Shear band dynamics from a mesoscopic modeling of plasticity
E. A. Jagla
2010-06-07T23:59:59.000Z
The ubiquitous appearance of regions of localized deformation (shear bands) in different kinds of disordered materials under shear is studied in the context of a mesoscopic model of plasticity. The model may or may not include relaxational (aging) effects. In the absence of relaxational effects the model displays a monotonously increasing dependence of stress on strain-rate, and stationary shear bands do not occur. However, in start up experiments transient (although long lived) shear bands occur, that widen without bound in time. I investigate this transient effect in detail, reproducing and explaining a t^1/2 law for the thickness increase of the shear band that has been obtained in atomistic numerical simulations. Relaxation produces a negative sloped region in the stress vs. strain-rate curve that stabilizes the formation of shear bands of a well defined width, which is a function of strain-rate. Simulations at very low strain-rates reveal a non-trivial stick-slip dynamics of very thin shear bands that has relevance in the study of seismic phenomena. In addition, other non-stationary processes, such as stop-and-go, or strain-rate inversion situations display a phenomenology that matches very well the results of recent experimental studies.
Modeling of air currents in the Gulf Region
Sullivan, T.J.; Ellis, J.S.; Foster, C.S.; Foster, K.T.; Baskett, R.L.; Nasstrom, J.S.; Schalk, W.W.
1992-04-14T23:59:59.000Z
The Atmospheric Release Advisory Capability modeled the wind flow in the Gulf Region in order to make projections of the Kuwait oil fires pollution dispersion. Extensive meteorological models incorporating explicit terrain influences to the flow fields were routinely employed through a six month international assessment support effort organized by the World Meteorological Organization and US scientific research agencies. Results show generally close agreement with visible imagery of the smoke plumes as detected by meteorological satellites. However, there are some examples of significant disagreement or failure of the meteorological models. These failures are most likely directly linked to missing or unavailable weather observations.
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
Open problem: Dynamic Relational Models for Improved Hazardous Weather Prediction
McGovern, Amy
. Current weather radar detection and prediction sys- tems primarily rely on numerical models. We proposeOpen problem: Dynamic Relational Models for Improved Hazardous Weather Prediction Amy McGovern1, #12;Dynamic Relational Models for Improved Hazardous Weather Prediction Radar velocity Radar
HOMOGENEOUS MODELS IN GENERAL RELATIVITY AND GAS DYNAMICS
Novikov, Sergei Petrovich
HOMOGENEOUS MODELS IN GENERAL RELATIVITY AND GAS DYNAMICS O. I. BOGOYAVLENSKII AND S. P. NOVIKOV analytically) in general relativity and gas dynamics. The investigation of these models is carried out begins with a short survey of results on non-trivial models (that is, those that are not integrable
Overview Electricity requirements Natural gas prices Wholesale electricity prices Regional Portfolio Model #12;Page 2 3 Electricity RequirementsElectricity Requirements 5th Plan Non-DSI Price Effects Sales Forecasts 12000 14000% 20% 30% 40% 50% 60% 70% 80% 90% 100% #12;Page 5 9 Wholesale Electricity PricesWholesale Electricity
Regional forecasting with global atmospheric models; Final report
Crowley, T.J.; Smith, N.R. [Applied Research Corp., College Station, TX (United States)
1994-05-01T23:59:59.000Z
The purpose of the project was to conduct model simulations for past and future climate change with respect to the proposed Yucca Mtn. repository. The authors report on three main topics, one of which is boundary conditions for paleo-hindcast studies. These conditions are necessary for the conduction of three to four model simulations. The boundary conditions have been prepared for future runs. The second topic is (a) comparing the atmospheric general circulation model (GCM) with observations and other GCMs; and (b) development of a better precipitation data base for the Yucca Mtn. region for comparisons with models. These tasks have been completed. The third topic is preliminary assessments of future climate change. Energy balance model (EBM) simulations suggest that the greenhouse effect will likely dominate climate change at Yucca Mtn. for the next 10,000 years. The EBM study should improve rational choice of GCM CO{sub 2} scenarios for future climate change.
Lindner, Benjamin [ORNL] [ORNL; Petridis, Loukas [ORNL] [ORNL; Schulz, Roland [ORNL] [ORNL; Smith, Jeremy C [ORNL] [ORNL
2013-01-01T23:59:59.000Z
The precipitation of lignin onto cellulose after pretreatment of lignocellulosic biomass is an obstacle to economically viable cellulosic ethanol production. Here, 750 ns nonequilibrium molecular dynamics simulations are reported of a system of lignin and cellulose in aqueous solution. Lignin is found to strongly associate with itself and the cellulose. However, noncrystalline regions of cellulose are observed to have a lower tendency to associate with lignin than crystalline regions, and this is found to arise from stronger hydration of the noncrystalline chains. The results suggest that the recalcitrance of crystalline cellulose to hydrolysis arises not only from the inaccessibility of inner fibers but also due to the promotion of lignin adhesion.
Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile
Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile Robot. It actively balances and moves on a single wheel using closed loop feedback, making it dynamically stable it a good candidate for operating in human environments. Balancing on a ball allows Ballbot to be omni
A dynamic model for the Lagrangian stochastic dispersion coefficient
Pesmazoglou, I.; Navarro-Martinez, S., E-mail: s.navarro@imperial.ac.uk [Department of Mechanical Engineering, Imperial College, London SW7 2AZ (United Kingdom); Kempf, A. M. [Chair of Fluid Dynamics, Institute for Combustion and Gasdynamics and Center for Computational Sciences and Simulation, Universität Duisburg-Essen, Duisburg, 47048 (Germany)] [Chair of Fluid Dynamics, Institute for Combustion and Gasdynamics and Center for Computational Sciences and Simulation, Universität Duisburg-Essen, Duisburg, 47048 (Germany)
2013-12-15T23:59:59.000Z
A stochastic sub-grid model is often used to accurately represent particle dispersion in turbulent flows using large eddy simulations. Models of this type have a free parameter, the dispersion coefficient, which is not universal and is strongly grid-dependent. In the present paper, a dynamic model for the evaluation of the coefficient is proposed and validated in decaying homogeneous isotropic turbulence. The grid dependence of the static coefficient is investigated in a turbulent mixing layer and compared to the dynamic model. The dynamic model accurately predicts dispersion statistics and resolves the grid-dependence. Dispersion statistics of the dynamically calculated constant are more accurate than any static coefficient choice for a number of grid spacings. Furthermore, the dynamic model produces less numerical artefacts than a static model and exhibits smaller sensitivity in the results predicted for different particle relaxation times.
Regional-Scale Climate Change: Observations and Model Simulations
Raymond S. Bradley; Henry F. Diaz
2010-12-14T23:59:59.000Z
This collaborative proposal addressed key issues in understanding the Earthâ??s climate system, as highlighted by the U.S. Climate Science Program. The research focused on documenting past climatic changes and on assessing future climatic changes based on suites of global and regional climate models. Geographically, our emphasis was on the mountainous regions of the world, with a particular focus on the Neotropics of Central America and the Hawaiian Islands. Mountain regions are zones where large variations in ecosystems occur due to the strong climate zonation forced by the topography. These areas are particularly susceptible to changes in critical ecological thresholds, and we conducted studies of changes in phonological indicators based on various climatic thresholds.
Stochastic modeling of lift and drag dynamics under turbulent conditions
Peinke, Joachim
measurement. The model is being developed with the aim to integrate it into a general wind energy converter dynamics, drag dynamics. 1 Introduction Wind energy converters (WECs) are permanently exposed to turbulent.peinke@forwind.de in every second, which imposes different risks. The dynamical nature of the wind has a significant impact
Event-Based Approach to Modelling Dynamic Architecture
Paris-Sud XI, UniversitÃ© de
Event-Based Approach to Modelling Dynamic Architecture: Application to Mobile Ad-Hoc Network.Attiogbe@univ-nantes.fr Abstract. We describe an event-based approach to specifiy systems with dynamically evolving architecture tools. Keywords: Specification, Verification, Dynamic Architecture, Event B. 1 Introduction Distributed
Dynamic Modeling of a Two Wheeled Vehicle : Jourdain Formalism
Paris-Sud XI, UniversitÃ© de
This paper presents a motorcycle direct dynamic formulation by the Jourdain's principle approach on the motorcycle's handlebar. Simulation results reveal some dynamics features like load transfer and counter-steering phenomena. keywords Motorcycle modeling, motorcycle control, Jourdain's dynamics principle. 1 Introduction
On connecting the dynamics of the chromosphere and transition region with Hinode SOT and EIS
Viggo H. Hansteen; Bart De Pontieu; Mats Carlsson; Scott McIntosh; Tetsuya Watanabe; Harry Warren; Louise Harra; Hirohisa Hara; Theodore D. Tarbell; Dick Shine; Alan Title; Carolus J. Schrijver; Saku Tsuneta; Yukio Katsukawa; Kiyoshi Ichimoto; Yoshinori Suematsu; Toshifumi Shimizu
2007-11-04T23:59:59.000Z
We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric and TR imaging and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric magnetic fields and the ubiquitous chromospheric waves. Initial analysis shows that these connections are quite subtle and require a combination of techniques including magnetic field extrapolations, frequency-filtered time-series and comparisons with synthetic chromospheric and TR images from advanced 3D numerical simulations. As a first result, we find signatures of magnetic flux emergence as well as 3 and 5 mHz wave power above regions of enhanced photospheric magnetic field in both chromospheric, transition region and coronal emission.
Dynamic Transitions in a Two Dimensional Associating Lattice Gas Model
Marcia M. Szortyka; Vera Henriques; Mauricio Girardi; Marcia C. Barbosa
2009-02-10T23:59:59.000Z
Using Monte Carlo simulations we investigate some new aspects of the phase diagram and the behavior of the diffusion coefficient in an associating lattice gas (ALG) model on different regions of the phase diagram. The ALG model combines a two dimensional lattice gas where particles interact through a soft core potential and orientational degrees of freedom. The competition between soft core potential and directional attractive forces results in a high density liquid phase, a low density liquid phase, and a gas phase. Besides anomalies in the behavior of the density with the temperature at constant pressure and of the diffusion coefficient with density at constant temperature are also found. The two liquid phases are separated by a coexistence line that ends in a bicritical point. The low density liquid phase is separated from the gas phase by a coexistence line that ends in tricritical point. The bicritical and tricritical points are linked by a critical $\\lambda$-line. The high density liquid phase and the fluid phases are separated by a second $\\tau$ critical line. We then investigate how the diffusion coefficient behaves on different regions of the chemical potential-temperature phase diagram. We find that diffusivity undergoes two types of dynamic transitions: a fragile-to-strong trans ition when the critical $\\lambda$-line is crossed by decreasing the temperature at a constant chemical potential; and a strong-to-strong transition when the $\\tau$-critical line is crossed by decreasing the temperature at a constant chemical potential.
A dynamic term structure model of Central Bank policy
Staker, Shawn W
2009-01-01T23:59:59.000Z
This thesis investigates the implications of explicitly modeling the monetary policy of the Central Bank within a Dynamic Term Structure Model (DTSM). We follow Piazzesi (2005) and implement monetary policy by including ...
A Qualitative Simulation Approach for Fuzzy Dynamical Models
Bontempi, Gianluca
.g., a nuclear power plant in unexpected emergency situations) or because if does not yet exist (eA Qualitative Simulation Approach for Fuzzy Dynamical Models ANDREA BONARINI and GIANLUCA BONTEMPI Politecnico di Milano This article deal with simulation of approximate models of dynamic systems. We propose
Direct modelling of envelope dynamics in resonant inverters
Direct 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 tank and simplify analysis and controller design. Introduction: High-frequency DC-AC inverters
Static and Dynamic Debugging of Modelica Models Adrian Pop1
Zhao, Yuxiao
Static and Dynamic Debugging of Modelica Models Adrian Pop1 , Martin Sjölund1 , Adeel Asghar1@elet.polimi.it Abstract The high abstraction level of equation-based object- oriented languages (EOO) such as Modelica has and dynamic debugging methods for Modelica models and a debugger prototype that addresses several of those
Koyama, Takeshi [Department of Applied Physics, Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Ito, Yoshito; Yoshida, Kazuma [Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Ago, Hiroki [Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka 816-8580, Japan and Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Nakamura, Arao [Department of Applied Physics, Nagoya University, Chikusa, Nagoya 464-8603, Japan and Toyota Physical and Chemical Research Institute, Nagakute, Aichi 480-1192 (Japan)
2013-12-04T23:59:59.000Z
We investigate the dynamics of photoexcited carriers in a single monolayer graphene at room temperature in air by femtosecond time-resolved luminescence measurements. The luminescence kinetics observed in the near-infrared region from 0.7 to 0.9 eV are analyzed based on the two-temperature model describing the cooling of thermalized carriers due to the carrier-optical-phonon coupling. The observed luminescence kinetics are well reproduced by the model, though the calculated electron temperature increases only to ?420 K at the maximum, which is much lower than the optical phonon energies. This indicates the predominance of optical phonons over acoustic phonons in the carrier-phonon interaction even at a temperature of ?400 K.
MODELING SUPER-FAST MAGNETOSONIC WAVES OBSERVED BY SDO IN ACTIVE REGION FUNNELS
Ofman, L. [Department of Physics, Catholic University of America, Washington, DC 20064 (United States); Liu, W.; Title, A.; Aschwanden, M. [Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States)
2011-10-20T23:59:59.000Z
Recently, quasi-periodic, rapidly propagating waves have been observed in extreme ultraviolet by the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) instrument in about 10 flare/coronal mass ejection (CME) events thus far. A typical example is the 2010 August 1 C3.2 flare/CME event that exhibited arc-shaped wave trains propagating in an active region (AR) magnetic funnel with {approx}5% intensity variations at speeds in the range of 1000-2000 km s{sup -1}. The fast temporal cadence and high sensitivity of AIA enabled the detection of these waves. We identify them as fast magnetosonic waves driven quasi-periodically at the base of the flaring region and develop a three-dimensional MHD model of the event. For the initial state we utilize the dipole magnetic field to model the AR and include gravitationally stratified density at coronal temperature. At the coronal base of the AR, we excite the fast magnetosonic wave by periodic velocity pulsations in the photospheric plane confined to a funnel of magnetic field lines. The excited fast magnetosonic waves have similar amplitude, wavelength, and propagation speeds as the observed wave trains. Based on the simulation results, we discuss the possible excitation mechanism of the waves, their dynamical properties, and the use of the observations for coronal MHD seismology.
Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model
Fringer, Oliver B.
Modeling dilute sediment suspension using large-eddy simulation with a dynamic mixed model Yi Transport of suspended sediment in high Reynolds number channel flows Re=O 600 000 is simulated using large-eddy simulation along with a dynamic-mixed model DMM . Because the modeled sediment concentration is low
Modeling Dynamic Receptive Field Changes in Primary Visual Cortex Using Inhibitory Learning
1997-01-01T23:59:59.000Z
The position, size, and shape of the visual receptive field (RF) of some primary visual cortical neurons change dynamically, in response to artificial scotoma conditioning in cats (Pettet & Gilbert, 1992) and to retinal lesions in cats and monkeys (DarianSmith & Gilbert, 1995). The "EXIN" learning rules (Marshall, 1995) are used to model dynamic RF changes. The EXIN model is compared with an adaptation model (Xing & Gerstein, 1994) and the LISSOM model (Sirosh & Miikkulainen, 1994; Sirosh et al., 1996). To emphasize the role of the lateral inhibitory learning rules, the EXIN and the LISSOM simulations were done with only lateral inhibitory learning. During scotoma conditioning, the EXIN model without feedforward learning produces centrifugal expansion of RFs initially inside the scotoma region, accompanied by increased responsiveness, without changes in spontaneous activation. The EXIN model without feedforward learning is more consistent with the neurophysiological data than are the a...
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.
Xu, Haiping
FORMAL SEMANTICS AND VERIFICATION OF DYNAMIC RELIABILITY BLOCK DIAGRAMS FOR SYSTEM RELIABILITY captured by existing reliability modeling tools. In this paper, we introduce a new reliability modeling tool, called dynamic reliability block diagrams (DRBD), for modeling dynamic relationships between
Lei, Huimin; Yang, Dawen; Huang, Maoyi
2014-04-16T23:59:59.000Z
Climate and atmospheric CO2 concentration have changed significantly in the mountainous region of the Haihe River basin over the past five decades. In the study, a process-based terrestrial model, version 4 of the Community Land Model (CLM4), was used to quantify the spatiotemporal changes in runoff over the region, driven by the varying climate factors and CO2 concentration. Overall, our simulations suggest that climate-induced change in runoff in this region show a decreasing trend since 1960. Changes in precipitation, solar radiation, air temperature, and wind speed accounts for 56%, -14%, 13%, -5% of the overall decrease in annual runoff, respectively, but their relative contributions vary across the study area. Rising atmospheric CO2 concentration was found to have limited impacts on runoff. Significant decrease in runoff over the southern and northeastern portion of the region is primarily attributed to decreasing precipitation, while decreasing solar radiation and increasing air temperature are the main causes of slight runoff increase in the northern portion. Our results also suggest that the magnitude of decreasing trend could be greatly underestimated if the dynamical interactions of vegetation phenology with the environmental factors are not considered in the modeling, highlighting the importance of including dynamic vegetation phenology in the prediction of runoff in this region.
Ye, Sheng; Li, Hongyi; Huang, Maoyi; Ali, Melkamu; Leng, Guoyong; Leung, Lai-Yung R.; Wang, Shaowen; Sivapalan, Murugesu
2014-07-21T23:59:59.000Z
Subsurface stormflow is an important component of the rainfall–runoff response, especially in steep terrain. Its contribution to total runoff is, however, poorly represented in the current generation of land surface models. The lack of physical basis of these common parameterizations precludes a priori estimation of the stormflow (i.e. without calibration), which is a major drawback for prediction in ungauged basins, or for use in global land surface models. This paper is aimed at deriving regionalized parameterizations of the storage–discharge relationship relating to subsurface stormflow from a top–down empirical data analysis of streamflow recession curves extracted from 50 eastern United States catchments. Detailed regression analyses were performed between parameters of the empirical storage–discharge relationships and the controlling climate, soil and topographic characteristics. The regression analyses performed on empirical recession curves at catchment scale indicated that the coefficient of the power-law form storage–discharge relationship is closely related to the catchment hydrologic characteristics, which is consistent with the hydraulic theory derived mainly at the hillslope scale. As for the exponent, besides the role of field scale soil hydraulic properties as suggested by hydraulic theory, it is found to be more strongly affected by climate (aridity) at the catchment scale. At a fundamental level these results point to the need for more detailed exploration of the co-dependence of soil, vegetation and topography with climate.
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 wind turbine models in power system simulation tool
Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D. Hansen, Florin Iov Iov, Poul SÃ¸rensen, Nicolaos Cutululis, Clemens Jauch, Frede Blaabjerg Title: Dynamic wind turbine system simulation tool PowerFactory DIgSILENT for different wind turbine concepts. It is the second
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
REGULAR ARTICLE A Simple Dynamic Model of Respiratory Pump
Fontecave-Jallon, Julie
). Mathematical models are used to understand these interactions and the mechanics of respiratory system better) and introduce some dynamic properties of the respiratory system. The passive elements (rib cage and abdomen not take into account the dynamic component of the system, it appears valid for different respiratory
Modeling and Management of Nonlinear Dependencies Copulas in Dynamic Financial
Ulm, Universität
an important tool for decision making and an essential part of enterprise risk management (ERM), particularly. Keywords: Non-Life Insurance, Risk Management, Dynamic Financial Analysis, Co- pulas, PerformanceModeling and Management of Nonlinear Dependencies Copulas in Dynamic Financial Analysis Martin
A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling
Paris-Sud XI, UniversitÃ© de
A New Motorcycle Simulator Platform: Mechatronics Design, Dynamics Modeling and Control L. Nehaoua of these techniques to other simulators (cars and motorcycles) is possible but not direct. Indeed, the dynamics motorcycle driving simulators were build. The first prototype was developed by Honda in 1988
Symbolic Dynamics in a Matching Labour Market Model
Diana A. Mendes; Vivaldo M. Mendes; J. Sousa Ramos
2006-08-01T23:59:59.000Z
In this paper we apply the techniques of symbolic dynamics to the analysis of a labor market which shows large volatility in employment flows. In a recent paper, Bhattacharya and Bunzel \\cite{BB} have found that the discrete time version of the Pissarides-Mortensen matching model can easily lead to chaotic dynamics under standard sets of parameter values. To conclude about the existence of chaotic dynamics in the numerical examples presented in the paper, the Li-Yorke theorem or the Mitra sufficient condition were applied which seems questionable because they may lead to misleading conclusions. Moreover, in a more recent version of the paper, Bhattacharya and Bunzel \\cite{BB1} present new results in which chaos is completely removed from the dynamics of the model. Our paper explores the matching model so interestingly developed by the authors with the following objectives in mind: (i) to show that chaotic dynamics may still be present in the model for standard parameter values; (ii) to clarify some open questions raised by the authors in \\cite{BB}, by providing a rigorous proof of the existence of chaotic dynamics in the model through the computation of topological entropy in a symbolic dynamics setting.
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. ...
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 ...
Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion
. Lozano June 2010 SSL # 6-10 #12;#12;Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion Nanako Takahashi, Paulo C. Lozano June 2010 SSL # 6-10 This work is based on the unaltered text
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 ...
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 ...
Models of dynamic RNA regulation in mammalian cells
Rabani, Michal
2013-01-01T23:59:59.000Z
Complex molecular circuits, consisting of multiple intertwined feedback loops and non-linear interactions, are a hallmark of every living cell, and a model of a dynamic complex network. Here, I systematically study the ...
Modeling exchange rate dependence dynamics at different time horizons
Embrechts, Paul
, Copula-GARCH, Conditional dependence, Dynamic copula Corresponding author. Tel.: +44(0) 247 657 4297. Financial time-series are often modeled with GARCH type models. In the multivariate GARCH literature there exist several models, like CCC- GARCH, DVEC, matrix-diagonal GARCH, BEKK and principal components GARCH
Cognitive Modeling Carsten Pfeffer Dynamical Systems Approaches to
Bremen, UniversitÃ¤t
Cognitive Modeling Carsten Pfeffer Dynamical Systems Approaches to Cognition Carsten Pfeffer UniversitÃ¤t Bremen December 1st, 2014 December 1st, 2014 1/30 #12;Cognitive Modeling Carsten Pfeffer Introduction Physical Symbol Systems December 1st, 2014 2/30 #12;Cognitive Modeling Carsten Pfeffer
Improvement of snowpack simulations in a regional climate model
Jin, J.; Miller, N.L.
2011-01-10T23:59:59.000Z
To improve simulations of regional-scale snow processes and related cold-season hydroclimate, the Community Land Model version 3 (CLM3), developed by the National Center for Atmospheric Research (NCAR), was coupled with the Pennsylvania State University/NCAR fifth-generation Mesoscale Model (MM5). CLM3 physically describes the mass and heat transfer within the snowpack using five snow layers that include liquid water and solid ice. The coupled MM5–CLM3 model performance was evaluated for the snowmelt season in the Columbia River Basin in the Pacific Northwestern United States using gridded temperature and precipitation observations, along with station observations. The results from MM5–CLM3 show a significant improvement in the SWE simulation, which has been underestimated in the original version of MM5 coupled with the Noah land-surface model. One important cause for the underestimated SWE in Noah is its unrealistic land-surface structure configuration where vegetation, snow and the topsoil layer are blended when snow is present. This study demonstrates the importance of the sheltering effects of the forest canopy on snow surface energy budgets, which is included in CLM3. Such effects are further seen in the simulations of surface air temperature and precipitation in regional weather and climate models such as MM5. In addition, the snow-season surface albedo overestimated by MM5–Noah is now more accurately predicted by MM5–CLM3 using a more realistic albedo algorithm that intensifies the solar radiation absorption on the land surface, reducing the strong near-surface cold bias in MM5–Noah. The cold bias is further alleviated due to a slower snowmelt rate in MM5–CLM3 during the early snowmelt stage, which is closer to observations than the comparable components of MM5–Noah. In addition, the over-predicted precipitation in the Pacific Northwest as shown in MM5–Noah is significantly decreased in MM5 CLM3 due to the lower evaporation resulting from the longer snow duration.
Improving the Simulation of the West African Monsoon Using the MIT Regional Climate Model
Im, Eun-Soon
This paper presents an evaluation of the performance of the Massachusetts Institute of Technology (MIT) regional climate model (MRCM) in simulating the West African monsoon. The MRCM is built on the Regional Climate Model, ...
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.
A Global, Multi-Resolution Approach to Regional Ocean Modeling
Du, Qiang
2013-11-08T23:59:59.000Z
In this collaborative research project between Pennsylvania State University, Colorado State University and Florida State University, we mainly focused on developing multi-resolution algorithms which are suitable to regional ocean modeling. We developed hybrid implicit and explicit adaptive multirate time integration method to solve systems of time-dependent equations that present two signi#12;cantly di#11;erent scales. We studied the e#11;ects of spatial simplicial meshes on the stability and the conditioning of fully discrete approximations. We also studies adaptive #12;nite element method (AFEM) based upon the Centroidal Voronoi Tessellation (CVT) and superconvergent gradient recovery. Some of these techniques are now being used by geoscientists(such as those at LANL).
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.
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.
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.
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.
Sloan, Lisa C
2005-01-01T23:59:59.000Z
snow accumulation (mm snow water equivalent) by region.Bell, J.L. , Jour. American Water Resources Assoc. , 591-CO, 1993. Department of Water Resources (DWR), California
Breazeale, K. [ed.; Isaak, D.T.; Yamaguchi, N.; Fridley, D.; Johnson, C.; Long, S.
1993-12-01T23:59:59.000Z
This report in the Hawaii Energy Strategy Project examines world and regional fossil energy dynamics. The topics of the report include fossil energy characteristics, the world oil industry including reserves, production, consumption, exporters, importers, refining, products and their uses, history and trends in the global oil market and the Asia-Pacific market; world gas industry including reserves, production, consumption, exporters, importers, processing, gas-based products, international gas market and the emerging Asia-Pacific gas market; the world coal industry including reserves, classification and quality, utilization, transportation, pricing, world coal market, Asia-Pacific coal outlook, trends in Europe and the Americas; and environmental trends affecting fossil fuels. 132 figs., 46 tabs.
Regional Oxidant Model (ROM), Source code and test data (Version 2. 1). Model-Simulation
Not Available
1991-01-01T23:59:59.000Z
The Regional Oxidant Model (ROM) is a three-dimensional photochemical Eulerian grid model designed to simulate ambient concentrations of ozone and related species. ROM is a 3-layer model with a horizontal resolution of approximately 19 km; each grid cell has dimensions of 1/6 degree latitude by 1/4 degree longitude. The typical horizontal extent of the modeling domain is 1000 km. The model is designed to simulate hourly regional concentrations of ozone during largely stagnant summertime conditions that are associated with elevated smog episodes. The model is designed so that its preprocessors run on a VAX and the core model runs on an IBM mainframe. A typical 3-day simulation of the core model for the northeastern U.S. uses 9.5 hours of CPU on an IBM 3090. A total of 19 computer tapes comprise the release of the ROM (Version 2.1). Six of the tapes were generated on an IBM, and 13 tapes were generated on a VAX. The tapes contain source code, sample runstreams, and test data for a 3-day simulation. Potential users of the ROM should be aware that the modeling system is complex and requires extensive computer resources. The services of engineers, meteorologists, or computer scientists experienced in photochemical grid modeling are required.
Regional Oxidant Model (ROM), (Source code only) (Version 2. 1). Model-Simulation
Not Available
1991-01-01T23:59:59.000Z
The Regional Oxidant Model (ROM) is a three-dimensional photochemical Eulerian grid model designed to simulate ambient concentrations of ozone and related species. ROM is a 3-layer model with a horizontal resolution of approximately 19 km; each grid cell has dimensions of 1/6 degree latitude by 1/4 degree longitude. The typical horizontal extent of the modeling domain is 1000 km. The model is designed to simulate hourly regional concentrations of ozone during largely stagnant summertime conditions that are associated with elevated smog episodes. The model is designed so that its preprocessors run on a VAX and the core model runs on an IBM mainframe. A typical 3-day simulation of the core model for the northeastern U.S. uses 9.5 hours of CPU on an IBM 3090. A total of 19 computer tapes comprise this release of the ROM (Version 2.1). Six of the tapes were generated on an IBM, and 13 tapes were generated on a VAX. The tapes contain source code, sample runstreams, and test data for a 3-day simulation. Potential users of the ROM should be aware that the modeling system is complex and requires extensive computer resources. The services of engineers, meteorologists, or computer scientists experienced in photochemical grid modeling are required.
Dynamic physiological modeling for functional diffuse optical tomography
,c and David A. Boasa a Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging and brain that reflect competing metabolic demands and cardiovascular dynamics. The diffuse nature of near- namic response. In this paper, we present a linear state-space model for DOT analysis that models
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 Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae
Boyer, Edmond
A Dynamic Model coupling Photoacclimation and Photoinhibition in Microalgae Philipp Hartmann1, Andreas Nikolaou2, Beno^it Chachuat2, Olivier Bernard1 Abstract-- Microalgae are often considered in microalgae, thereby spanning multiple time scales. The properties of the model are investigated under quasi
Computational Modeling of Brain Dynamics during Repetitive Head Motions
Burtscher, Martin
Computational Modeling of Brain Dynamics during Repetitive Head Motions Igor Szczyrba School motions in traumatic scenarios that are as- sociated with severe brain injuries. Our results are based on the linear Kelvin-Voigt brain injury model, which treats the brain matter as a viscoelastic solid, and on our
Passive dynamic walking with knees : a point foot model
Hsu Chen, Vanessa F. (Vanessa Fang)
2007-01-01T23:59:59.000Z
In this thesis, a hybrid model for a passive 2D walker with knees and point feet is presented. The step cycle of the model has two phases of continuous dynamics: one with an unlocked knee configuration and a second one ...
Dynamic modelling for thermal micro-actuators using thermal networks
Paris-Sud XI, UniversitÃ© de
Dynamic modelling for thermal micro-actuators using thermal networks Beatriz LÂ´opez-Wallea,1 and analytical calculations. Key words: Micro-actuators, Thermal modelling, Electrical analogy, Thermal network 1 and MicroMechatronic Systems Department (AS2M), 24 rue Alain Savary, 25000 BesanÂ¸con, France Abstract
Long-wave models of thin film fluid dynamics
A. J. Roberts
1994-11-04T23:59:59.000Z
Centre manifold techniques are used to derive rationally a description of the dynamics of thin films of fluid. The derived model is based on the free-surface $\\eta(x,t)$ and the vertically averaged horizontal velocity $\\avu(x,t)$. The approach appears to converge well and has significant differences from conventional depth-averaged models.
Modeling Lake Erie ice dynamics: Process studies , Haoguo Hu2
Modeling Lake Erie ice dynamics: Process studies Jia Wang1 , Haoguo Hu2 , and Xuezhi Bai2 1 NOAA of Michigan 4840 S. State Road, Ann Arbor, MI 48108 Abstract. A Great Lakes Ice-circulation Model (GLIM derived from meteorological measurements. After the seasonal cycles of ice concentration, thickness
Assessing the reliability of linear dynamic transformer thermal modelling
Assessing the reliability of linear dynamic transformer thermal modelling X. Mao, D.J. Tylavsky and G.A. McCulla Abstract: Improving the utilisation of transformers requires that the hot-spot and top. An alternative method for assessing transformer model reliability is provided. 1 Introduction The maximally
Variational Inference in Stochastic Dynamic Environmental Models Dan Cornford1
Roulstone, Ian
Variational Inference in Stochastic Dynamic Environmental Models Dan Cornford1 , Manfred Opper2 number of degrees of freedom. Environmental forecasting centres have taken strategic decisions to develop on related phenomena, such as flooding and storm damage, and on the spread of pollutants. The models needed
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.
Friction in a Model of Hamiltonian Dynamics
Juerg Froehlich; Zhou Gang; Avy Soffer
2011-10-29T23:59:59.000Z
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.
Stuart, J.G.; Wright, A.D.; Butterfield, C.P.
1996-10-01T23:59:59.000Z
Mitigating the effects of damaging wind turbine loads and responses extends the lifetime of the turbine and, consequently, reduces the associated Cost of Energy (COE). Active control of aerodynamic devices is one option for achieving wind turbine load mitigation. Generally speaking, control system design and analysis requires a reasonable dynamic model of {open_quotes}plant,{close_quotes} (i.e., the system being controlled). This paper extends the wind turbine aileron control research, previously conducted at the National Wind Technology Center (NWTC), by presenting a more detailed development of the wind turbine dynamic model. In prior research, active aileron control designs were implemented in an existing wind turbine structural dynamics code, FAST (Fatigue, Aerodynamics, Structures, and Turbulence). In this paper, the FAST code is used, in conjunction with system identification, to generate a wind turbine dynamic model for use in active aileron control system design. The FAST code is described and an overview of the system identification technique is presented. An aileron control case study is used to demonstrate this modeling technique. The results of the case study are then used to propose ideas for generalizing this technique for creating dynamic models for other wind turbine control applications.
Modeling of Alpine Atmospheric Dynamics II
Gohm, Alexander
for large mesh sizes (x 20 km) to vertically redistribute heat and moisture in a grid column when model in a numerical model Convective cloud systems are not resolved if the mesh size of the grid is larger than small to treat convection as sub-grid scale process but too large to treat it explicitly For example
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 force spectroscopy on multiple bonds: experiments and model
T. Erdmann; S. Pierrat; P. Nassoy; U. S. Schwarz
2007-12-18T23:59:59.000Z
We probe the dynamic strength of multiple biotin-streptavidin adhesion bonds under linear loading using the biomembrane force probe setup for dynamic force spectroscopy. Measured rupture force histograms are compared to results from a master equation model for the stochastic dynamics of bond rupture under load. This allows us to extract the distribution of the number of initially closed bonds. We also extract the molecular parameters of the adhesion bonds, in good agreement with earlier results from single bond experiments. Our analysis shows that the peaks in the measured histograms are not simple multiples of the single bond values, but follow from a superposition procedure which generates different peak positions.
A Markov model of land use dynamics
Campillo, Fabien; Raherinirina, Angelo; Rakotozafy, Rivo
2011-01-01T23:59:59.000Z
The application of the Markov chain to modeling agricultural succession is well known. In most cases, the main problem is the inference of the model, i.e. the estimation of the transition matrix. In this work we present methods to estimate the transition matrix from historical observations. In addition to the estimator of maximum likelihood (MLE), we also consider the Bayes estimator associated with the Jeffreys prior. This Bayes estimator will be approximated by a Markov chain Monte Carlo (MCMC) method. We also propose a method based on the sojourn time to test the adequation of Markov chain model to the dataset.
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 ...
On fast trust region methods for quadratic models with linear ...
2014-08-28T23:59:59.000Z
employs conjugate gradients with termination at the trust region boundary. In particular, we ... An extension to the conjugate gradient method for searching round.
A dynamic model of industrial energy demand in Kenya
Haji, S.H.H. [Gothenburg Univ. (Sweden)
1994-12-31T23:59:59.000Z
This paper analyses the effects of input price movements, technology changes, capacity utilization and dynamic mechanisms on energy demand structures in the Kenyan industry. This is done with the help of a variant of the second generation dynamic factor demand (econometric) model. This interrelated disequilibrium dynamic input demand econometric model is based on a long-term cost function representing production function possibilities and takes into account the asymmetry between variable inputs (electricity, other-fuels and Tabour) and quasi-fixed input (capital) by imposing restrictions on the adjustment process. Variations in capacity utilization and slow substitution process invoked by the relative input price movement justifies the nature of input demand disequilibrium. The model is estimated on two ISIS digit Kenyan industry time series data (1961 - 1988) using the Iterative Zellner generalized least square method. 31 refs., 8 tabs.
Clustering Properties of Dynamical Dark Energy Models
P. P. Avelino; L. M. G. Beca; C. J. A. P. Martins
2008-02-01T23:59:59.000Z
We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is coupled to dark matter.
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.
Models of Receptive Field Dynamics in Visual Cortex
1999-01-01T23:59:59.000Z
The position, size, and shape of the receptive field (RF) of some cortical neurons change dynamically, in response to artificial scotoma conditioning (Pettet & Gilbert, 1992) and to retinal lesions (Chino et al., 1992; Darian-Smith & Gilbert, 1995) in adult animals. The RF dynamics are of interest because they show how visual systems may adaptively overcome damage (from lesions, scotomas, or other failures), may enhance processing efficiency by altering RF coverage in response to visual demand, and may perform perceptual learning. This paper presents an afferent excitatory synaptic plasticity rule and a lateral inhibitory synaptic plasticity rule -- the EXIN rules (Marshall, 1995a) -- to model persistent RF changes after artificial scotoma conditioning and retinal lesions. The EXIN model is compared to the LISSOM model (Sirosh et al., 1996) and to a neuronal adaptation model (Xing & Gerstein, 1994). The rules within each model are isolated and are analyzed independently, to elucidate t...
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.
EMERGING DIMMINGS OF ACTIVE REGIONS OBSERVED BY THE SOLAR DYNAMICS OBSERVATORY
Zhang Jun; Yang Shuhong [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Liu Yang; Sun Xudong, E-mail: zjun@nao.cas.cn, E-mail: shuhongyang@nao.cas.cn, E-mail: yliu@sun.stanford.edu, E-mail: xudong@sun.stanford.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States)
2012-12-01T23:59:59.000Z
Using the observations from the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we statistically investigate the emerging dimmings (EDs) of 24 isolated active regions (IARs) from 2010 June to 2011 May. All the IARs show EDs in lower-temperature lines (e.g., 171 A) at their early emerging stages. Meanwhile, in higher temperature lines (e.g., 211 A), the ED regions brighten continuously. There are two types of EDs: fan-shaped and halo-shaped. There are 19 fan-shaped EDs and 5 halo-shaped ones. The EDs appear to be delayed by several to more than ten hours relative to the first emergence of the IARs. The shortest delay is 3.6 hr and the longest is 19.0 hr. The EDs last from 3.3 hr to 14.2 hr, with a mean duration of 8.3 hr. Before the appearance of the EDs, the emergence rate of the magnetic flux of the IARs is between 1.2 Multiplication-Sign 10{sup 19} Mx hr{sup -1} to 1.4 Multiplication-Sign 10{sup 20} Mx hr{sup -1}. The larger the emergence rate is, the shorter the delay time is. While the dimmings appear, the magnetic flux of the IARs ranges from 8.8 Multiplication-Sign 10{sup 19} Mx to 1.3 Multiplication-Sign 10{sup 21} Mx. These observations imply that the reconfiguration of the coronal magnetic fields due to reconnection between the newly emerging flux and the surrounding existing fields results in a new thermal distribution which leads to a dimming for the cooler channel (171 A) and brightening in the warmer channels.
Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations
Brenner, Donald W.
Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations J 2004) An ad hoc thermostating procedure that couples a molecular dynamics (MD) simulation
Modeling Dynamic Landscapes in Open Source GIS
Mitasova, Helena
2013-11-20T23:59:59.000Z
is free online • message board discussion, help • Google sites: post HW, get feedback • register to get credit Solar radiation modeling: monthly totals Applications in urban areas: solar panels, building design, thermal conditions,… Helena Mitasova, NCSU... that is free to run, study, modify and distribute Free means freedom: free is a matter of liberty not price It can be commercial (Red Hat Linux) but not proprietary OSGeo foundation supports the development of open source geospatial software and promotes its...
High-frequency absorption of the dynamic mixed state in the surface superconductivity region
Berezin, V. A., E-mail: berezin@iptm.ru; Tulin, V. A., E-mail: tulin@iptm.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and High-Purity Materials (Russian Federation)
2013-03-15T23:59:59.000Z
We analyze the absorption of a high-frequency electromagnetic field in the type II superconductor Pb{sub 0.8}In{sub 0.2} in magnetic fields H{sub c2} < H < H{sub c3}. The absorption component proportional to the rate of variation of the external magnetic field is detected. We assume that this absorption component is associated with the dynamic mixed state of the superconducting shell containing 2D magnetic flux vortices (Kulik vortices). The motion of these vortices under the action of the critical current ensures the required difference between the external and internal magnetic inductions of the superconducting shell upon a change in the external magnetic field. This model correctly describes the observed behavior of absorption of rf electromagnetic radiation.
deYoung, Brad
The Social Dynamics of Economic Performance: Innovation and Creativity in City-Regions Newfoundland.......................................................4! INNOVATION AND CREATIVITY IN CITY-REGIONS ............................................................................6! INNOVATION AND CREATIVITY IN SMALL CITIES ON THE PERIPHERY
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...
ASTRO-H White Paper - Plasma Diagnostic and Dynamics of the Galactic Center Region
Koyama, K; Nobukawa, M; Uchiyama, H; Nakashima, S; Aharonian, F; Chernyakova, M; Ichinohe, Y; Nobukawa, K K; Maeda, Y; Matsumoto, H; Murakami, H; Ricci, C; Stawarz, L; Tanaka, T; Tsuru, T G; Watanabe, S; Yamauchi, S; Yuasa, T
2014-01-01T23:59:59.000Z
The most characteristic high-energy phenomena in the Galactic center (GC) region is the presence of strong K-shell emission lines from highly ionized Si, S, Ar, Ca, Fe and Ni, which form the Galactic Center X-ray Emission (GCXE). These multiple lines suggest that the GCXE is composed of at least two plasmas with temperatures of ~1 and ~7 keV. The GCXE also exhibits the K-shell lines from neutral Si, S, Ar, Ca, Fe and Ni atoms. A debatable issue is the origin of the GCXE plasma; whether it is a diffuse plasma or integrated emission of many unresolved point sources such as cataclysmic variables and active binaries. Detailed spectroscopy for these lines may provide a reliable picture of the GCXE plasma. The origin of the K-shell lines from neutral atoms is most likely the fluorescence by X-rays from a putative past flare of Sgr A*. Therefore ASTRO-H may provide unprecedented data for the past light curve of Sgr A*. All these lines may provide key information for the dynamics of the GCXE, using possible Doppler s...
Zheng Ruisheng; Jiang Yunchun; Yang Jiayan; Bi Yi; Hong Junchao; Yang, B.; Yang Dan, E-mail: zhrsh@ynao.ac.cn [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)
2012-03-01T23:59:59.000Z
Taking advantage of the high temporal and spatial resolution of the Solar Dynamics Observatory (SDO) observations, we present four homologous extreme ultraviolet (EUV) waves within 3 hr on 2010 November 11. All EUV waves emanated from the same emerging flux region (EFR), propagated in the same direction, and were accompanied by surges, weak flares, and faint coronal mass ejections (CMEs). The waves had the basically same appearance in all EUV wavebands of the Atmospheric Imaging Assembly on SDO. The waves propagated at constant velocities in the range of 280-500 km s{sup -1}, with little angular dependence, which indicated that the homologous waves could be likely interpreted as fast-mode waves. The waves are supposed to likely involve more than one driving mechanism, and it was most probable that the waves were driven by the surges, due to their close timing and location relations. We also propose that the homologous waves were intimately associated with the continuous emergence and cancellation of magnetic flux in the EFR, which could supply sufficient energy and trigger the onsets of the waves.
Hans Peter Schmid; Craig Wayson
2009-05-05T23:59:59.000Z
The primary objective of this project was to evaluate carbon exchange dynamics across a region of North America between the Great Plains and the East Coast. This region contains about 40 active carbon cycle research (AmeriFlux) sites in a variety of climatic and landuse settings, from upland forest to urban development. The core research involved a scaling strategy that uses measured fluxes of CO{sub 2}, energy, water, and other biophysical and biometric parameters to train and calibrate surface-vegetation-atmosphere models, in conjunction with satellite (MODIS) derived drivers. To achieve matching of measured and modeled fluxes, the ecosystem parameters of the models will be adjusted to the dynamically variable flux-tower footprints following Schmid (1997). High-resolution vegetation index variations around the flux sites have been derived from Landsat data for this purpose. The calibrated models are being used in conjunction with MODIS data, atmospheric re-analysis data, and digital land-cover databases to derive ecosystem exchange fluxes over the study domain.
DYNAMIC MODELLING OF AUTONOMOUS POWER SYSTEMS INCLUDING RENEWABLE POWER SOURCES.
Paris-Sud XI, UniversitÃ© de
(thermal, gas, diesel) and renewable (hydro, wind) power units. The objective is to assess the impact - that have a special dynamic behaviour, and the wind turbines. Detailed models for each one of the power system components are developed. Emphasis is given in the representation of different hydro power plant
A Model for Dynamic Reconfiguration in Service-oriented Architectures
Lopes, AntÃ³nia
A Model for Dynamic Reconfiguration in Service-oriented Architectures JosÂ´e Luiz Fiadeiro1 and Ant of service-oriented applications goes be- yond what is currently addressed by existing architecture of service-oriented applications. 1 Introduction Several architectural aspects arise from service-oriented
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
Dynamic Modeling and Recipe Optimization of Polyether Polyol Processes
Grossmann, Ignacio E.
Dynamic Modeling and Recipe Optimization of Polyether Polyol Processes Fall 2012 EWO Meeting Yisu Monomer Reactor Basic procedures Starters are first mixed with catalyst in the liquid phase Alkylene oxides in the liquid phase are fed in controlled rates The reactor temperature is controlled by the heat
FRW Cosmological model with Modified Chaplygin Gas and Dynamical System
Nairwita Mazumder; Ritabrata Biswas; Subenoy Chakraborty
2011-06-23T23:59:59.000Z
The Friedmann-Robertson-Walker(FRW) model with dynamical Dark Energy(DE) in the form of modified Chaplygin gas(MCG) has been investigated. The evolution equations are reduced to an autonomous system on the two dimensional phase plane and it can be interpreted as the motion of the particle in an one dimensional potential.
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
Fitting Dynamical Models to Observations of Globular Clusters
Dean E. McLaughlin
2003-02-14T23:59:59.000Z
The basic ingredients of models for the internal dynamics of globular clusters are reviewed, with an emphasis on the description of equilibrium configurations. The development of progressive complexity in the models is traced, concentrating on the inclusion of velocity anisotropy, rotation, and integrals of motion other than energy. Applications to observations of extragalactic globulars and to combined radial-velocity and proper-motion datasets are discussed.
The Dynamics of Brane-World Cosmological Models
A. A. Coley
2005-04-09T23:59:59.000Z
Brane-world cosmology is motivated by recent developments in string/M-theory and offers a new perspective on the hierarchy problem. In the brane-world scenario, our Universe is a four-dimensional subspace or {\\em brane} embedded in a higher-dimensional {\\em bulk} spacetime. Ordinary matter fields are confined to the brane while the gravitational field can also propagate in the bulk, leading to modifications of Einstein's theory of general relativity at high energies. In particular, the Randall-Sundrum-type models are self-consistent and simple and allow for an investigation of the essential non-linear gravitational dynamics. The governing field equations induced on the brane differ from the general relativistic equations in that there are nonlocal effects from the free gravitational field in the bulk, transmitted via the projection of the bulk Weyl tensor, and the local quadratic energy-momentum corrections, which are significant in the high-energy regime close to the initial singularity. In this review we discuss the asymptotic dynamical evolution of spatially homogeneous brane-world cosmological models containing both a perfect fluid and a scalar field close to the initial singularity. Using dynamical systems techniques it is found that, for models with a physically relevant equation of state, an isotropic singularity is a past-attractor in all orthogonal spatially homogeneous models (including Bianchi type IX models). In addition, we describe the dynamics in a class of inhomogeneous brane-world models, and show that these models also have an isotropic initial singularity. These results provide support for the conjecture that typically the initial cosmological singularity is isotropic in brane-world cosmology.
Mathematical Modeling of Microbial Community Dynamics: A Methodological Review
Song, Hyun-Seob; Cannon, William R.; Beliaev, Alex S.; Konopka, Allan
2014-10-17T23:59:59.000Z
Microorganisms in nature form diverse communities that dynamically change in structure and function in response to environmental variations. As a complex adaptive system, microbial communities show higher-order properties that are not present in individual microbes, but arise from their interactions. Predictive mathematical models not only help to understand the underlying principles of the dynamics and emergent properties of natural and synthetic microbial communities, but also provide key knowledge required for engineering them. In this article, we provide an overview of mathematical tools that include not only current mainstream approaches, but also less traditional approaches that, in our opinion, can be potentially useful. We discuss a broad range of methods ranging from low-resolution supra-organismal to high-resolution individual-based modeling. Particularly, we highlight the integrative approaches that synergistically combine disparate methods. In conclusion, we provide our outlook for the key aspects that should be further developed to move microbial community modeling towards greater predictive power.
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 ...
Model equations in rarefied gas dynamics: Viscous-slip and thermal-slip coefficients
Siewert, Charles E.
Model equations in rarefied gas dynamics: Viscous-slip and thermal-slip coefficients C. E. Siewert-slip and the thermal-slip coefficients in rarefied gas dynamics. More specifically, the BGK model, the S model In reviewing numerous papers devoted to model equa- tions in rarefied gas dynamics, we have found no definitive
goals of climate modeling. Water supports the ecosystems as well as a wide range of human activities to improve region- al predictions of the hydrologic cycle to address climate change impacts, adaptationDevelopment of Frameworks for Robust Regional Climate Modeling PRINCIPAL INVESTIGATOR: Moetasim
Space Mapping: Models, Sensitivities, and Trust-Regions Methods 1 ...
We consider also a di erent perspective of space mapping and apply it, ... built by composition of the space mapping and the coarse model is a regular function.
Probing dynamical processes in the planet forming region with dust mineralogy
McClure, M K; Calvet, N; Adame, L; Espaillat, C; Watson, D M; Sargent, B; Forrest, W J; D'Alessio, P
2012-01-01T23:59:59.000Z
We present Herschel Space Observatory PACS spectra of GQ Lup, a protoplanetary disk in the Lupus star-forming region. Through SED fitting from 0.3{\\mu}m to 1.3mm, we construct a self-consistent model of this system's temperature and density structures, finding that although it is 3 Myr old, its dust has not settled to the midplane substantially. The disk has a radial gradient in both the silicate dust composition and grain size, with large amorphous grains in the upper layers of the inner disk and an enhancement of submicron, crystalline grains in the outer disk. We detect an excess of emission in the Herschel PACS B2A band near 63{\\mu}m and model it with a combination of {\\sim}15 to 70{\\mu}m crystalline water ice grains with a size distribution consistent with ice recondensation-enhanced grain growth and a mass fraction half of that of our solar system. The combination of crystalline water ice and silicates in the outer disk is suggestive of disk-wide heating events or planetesimal collisions. If confirmed, ...
Einarsson, Baldvin; Birnir, Bjorn; Sigurðsson, Sven Þ.
2010-01-01T23:59:59.000Z
S.A.L.M. , 2010. Dynamic Energy Budget Theory For Metabolicthe use of dynamic energy budget theory. Biological Reviewsthrough dynamic energy budget models. Jour- nal of Animal
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.
A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin
Fay, Noah
A Groundwater Dynamic Simulation Model: Application to the Upper San Pedro Basin Report Prepared by using tools such as tracers to determine groundwater travel times and this dynamic simulation modeling
Statistical Model and the mesonic-baryonic transition region
H. Oeschler; J. Cleymans; K. Redlich; S. Wheaton
2009-10-12T23:59:59.000Z
The statistical model assuming chemical equilibriumand local strangeness conservation describes most of the observed features of strange particle production from SIS up to RHIC. Deviations are found as the maximum in the measured K+/pi+ ratio is much sharper than in the model calculations. At the incident energy of the maximum, the statistical model shows that freeze out changes regime from one being dominated by baryons at the lower energies toward one being dominated by mesons. It will be shown how deviations from the usual freeze-out curve influence the various particle ratios. Furthermore, other observables exhibit also changes just in this energy regime.
Data-based Construction of Convex Region Surrogate (CRS) Models
Grossmann, Ignacio E.
University Arul Sundaramoorthy, Jose M. Pinto Praxair Inc., Business and Supply Chain Optimization R Model of an Industrial Process. Real process data drawn from a Praxair plant Set 1 0.900 0.062 0
Convergence of trust-region methods based on probabilistic models
2013-10-24T23:59:59.000Z
the list of applications—including molecular geometry optimization, circuit design, ... A complex mechanism of sample set maintenance is ... shown that one can build such models, meeting a Taylor type accuracy with high probability,.
Dynamical Reduction Models: present status and future developments
A. Bassi
2007-02-08T23:59:59.000Z
We review the major achievements of the dynamical reduction program, showing why and how it provides a unified, consistent description of physical phenomena, from the microscopic quantum domain to the macroscopic classical one. We discuss the difficulties in generalizing the existing models in order to comprise also relativistic quantum field theories. We point out possible future lines of research, ranging from mathematical physics to phenomenology.
Dynamical Wave Function Collapse Models in Quantum Measure Theory
Fay Dowker; Yousef Ghazi-Tabatabai
2008-05-15T23:59:59.000Z
The structure of Collapse Models is investigated in the framework of Quantum Measure Theory, a histories-based approach to quantum mechanics. The underlying structure of coupled classical and quantum systems is elucidated in this approach which puts both systems on a spacetime footing. The nature of the coupling is exposed: the classical histories have no dynamics of their own but are simply tied, more or less closely, to the quantum histories.
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.
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.
Code description: A dynamic modelling strategy for Bayesian computer model emulation
West, Mike
Code description: A dynamic modelling strategy for Bayesian computer model emulation 1 Example data and code directory The example data is provided under the directory "mydata": Â· "design1.dat": this file2.dat": this file contains the 60 validation runs. The Matlab code is provided under the directory
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 (2004)). Large multiÂcity studies such as `Air pollution and health: a European approach' (APHEA across a number of US and European cities. ShortÂterm e#ects of air pollution on health are estimated
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.
Radiation-MHD models of elephant trunks and globules in H II regions
Mackey, Jonathan
2011-01-01T23:59:59.000Z
We study the formation and evolution of pillars of dense gas, known as elephant trunks, at the boundaries of H II regions, formed by shadowing of ionising radiation by dense clumps. The effects of magnetic fields on this process are investigated using 3D radiation-magnetohydrodynamics simulations. For a simulation in which an initially uniform magnetic field of strength |B|=50 uG is oriented perpendicular to the radiation propagation direction, the field is swept into alignment with the pillar during its dynamical evolution, in agreement with observations of the "Pillars of Creation" in M16, and of some cometary globules. This effect is significantly enhanced when the simulation is re-run with a weaker field of 18 uG. A stronger field with |B|=160 uG is sufficient to prevent this evolution completely, also significantly affecting the photoionisation process. Using a larger simulation domain it is seen that the pillar formation models studied in Mackey & Lim (2010) ultimately evolve to cometary structures ...
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.
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.
A validation of heat and carbon fluxes from highresolution land surface and regional models
D'Andrea, Fabio
) or regional climate models (RCMs) [Alessandri et al., 2007; Steiner et al., 2009]. [3., 2006; Alessandri et al., 2007; Jarlan et al., 2008; Steiner et al., 2009]. However, the SVAT models models do not account for the role of terrestrial vegetation in the carbon cycle variability [Alessandri
Causality Analysis of Groundwater dynamics based on a Vector Autoregressive model in the semi, time space analysis, causality, VAR model, semi-arid region 1. Introduction Large amounts of water. Abstract: Causal relationships existing between observed levels of groundwater in a semi-arid sub
Dynamic ModelingDynamic Modeling the Electric Power Networkthe Electric Power Network
Oro, Daniel
criteria to enter the wholesale market DEREGULATION PROCESS: FERC's Order 888 mandated the wheeling at the National Energy Modeling System/Annual Energy Outlook Conference, Washington, DC, March 10, 2003] #12
Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance Models
Mountziaris, T. J.
ARTICLES Optimization of Fed-Batch Saccharomyces cereWisiae Fermentation Using Dynamic Flux Balance metabolism with dynamic mass balances on key extracellular species. Model-based dynamic optimization concentration profiles, and the final batch time are treated as decision variables in the dynamic optimization
Fayer, Michael D.
Ultrafast Structural Dynamics Inside Planar Phospholipid Multibilayer Model Cell Membranes Measured diffusion caused by the structural dynamics of the membrane from 200 fs to 200 ps as a function structure and an abrupt change in dynamics at 35% cholesterol. The dynamics are independent of cholesterol
Dynamics of popstar record sales on phonographic market -- stochastic model
Jarynowski, Amdrzej
2013-01-01T23:59:59.000Z
We investigate weekly record sales of the world's most popular 30 artists (2003-2013). Time series of sales have non-trivial kind of memory (anticorrelations, strong seasonality and constant autocorrelation decay within 120 weeks). Amount of artists record sales are usually the highest in the first week after premiere of their brand new records and then decrease to fluctuate around zero till next album release. We model such a behavior by discrete mean-reverting geometric jump diffusion (MRGJD) and Markov regime switching mechanism (MRS) between the base and the promotion regimes. We can built up the evidence through such a toy model that quantifies linear and nonlinear dynamical components (with stationary and nonstationary parameters set), and measure local divergence of the system with collective behavior phenomena. We find special kind of disagreement between model and data for Christmas time due to unusual shopping behavior. Analogies to earthquakes, product life-cycles, and energy markets will also be d...
The Third State of the Schelling Model of Residential Dynamics
Benenson, Itzhak
2009-01-01T23:59:59.000Z
The Schelling model of segregation between two groups of residential agents (Schelling 1971; Schelling 1978) reflects the most abstract view of the non-economic forces of residential migrations: be close to people of 'your own'. The model assumes that the residential agent, located in the neighborhood where the fraction of 'friends' is less than a predefined threshold value F, tries to relocate to a neighborhood for which this fraction is above F. It is well known that for the equal groups, depending on F, Schelling's residential pattern converges either to complete integration (random pattern) or segregation. We investigate Schelling model pattern dynamics as dependent on F, the ratio of the group numbers and the size of the neighborhood and demonstrate that the traditional integrate-segregate dichotomy is incomplete. In case of unequal groups, there exists the wide interval of the F-values that entails the third persistent residential pattern, in which part of the majority population segregates, while the r...
Mechanical reaction-diffusion model for bacterial population dynamics
Ngamsaad, Waipot
2015-01-01T23:59:59.000Z
The effect of mechanical interaction between cells on the spreading of bacterial population was investigated in one-dimensional space. A nonlinear reaction-diffusion equation has been formulated as a model for this dynamics. In this model, the bacterial cells are treated as the rod-like particles that interact, when contacting each other, through the hard-core repulsion. The repulsion introduces the exclusion process that causes the fast diffusion in bacterial population at high density. The propagation of the bacterial density as the traveling wave front in long time behavior has been analyzed. The analytical result reveals that the front speed is enhanced by the exclusion process---and its value depends on the packing fraction of cell. The numerical solutions of the model have been solved to confirm this prediction.
A model of riots dynamics: shocks, diffusion and thresholds
Berestycki, Henri; Rodriguez, Nancy
2015-01-01T23:59:59.000Z
We introduce and analyze several variants of a system of differential equations which model the dynamics of social outbursts, such as riots. The systems involve the coupling of an explicit variable representing the intensity of rioting activity and an underlying (implicit) field of social tension. Our models include the effects of exogenous and endogenous factors as well as various propagation mechanisms. From numerical and mathematical analysis of these models we show that the assumptions made on how different locations influence one another and how the tension in the system disperses play a major role on the qualitative behavior of bursts of social unrest. Furthermore, we analyze here various properties of these systems, such as the existence of traveling wave solutions, and formulate some new open mathematical problems which arise from our work.
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.
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.
Cirpka, Olaf Arie
1 Integrated modelling and assessment of regional groundwater resources in Germany and Benin, West.J.S. SONNEVELD [1] Institute of Hydraulic Engineering, Universitaet Stuttgart, Germany (Roland Conservation University of Bonn, Germany [3] Institute of Landscape Planning and Ecology, University
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.
Towards a Simplified Dynamic Wake Model using POD Analysis
Bastine, David; Wächter, Matthias; Peinke, Joachim
2014-01-01T23:59:59.000Z
We apply the proper orthogonal decomposition (POD) to large eddy simulation data of a wind turbine wake in a turbulent atmospheric boundary layer. The turbine is modeled as an actuator disk. Our analyis mainly focuses on the question whether POD could be a useful tool to develop a simplified dynamic wake model. The extracted POD modes are used to obtain approximate descriptions of the velocity field. To assess the quality of these POD reconstructions, we define simple measures which are believed to be relevant for a sequential turbine in the wake such as the energy flux through a disk in the wake. It is shown that only a few modes are necessary to capture basic dynamical aspects of these measures even though only a small part of the turbulent kinetic energy is restored. Furthermore, we show that the importance of the individual modes depends on the measure chosen. Therefore, the optimal choice of modes for a possible model could in principle depend on the application of interest. We additionally present a pos...
Mai, T.; Drury, E.; Eurek, K.; Bodington, N.; Lopez, A.; Perry, A.
2013-01-01T23:59:59.000Z
This report introduces a new capacity expansion model, the Resource Planning Model (RPM), with high spatial and temporal resolution that can be used for mid- and long-term scenario planning of regional power systems. Although RPM can be adapted to any geographic region, the report describes an initial version of the model adapted for the power system in Colorado. It presents examples of scenario results from the first version of the model, including an example of a 30%-by-2020 renewable electricity penetration scenario.
Dynamic water wave pressures on a recurved model seawall
Rismiller, Gregory Ross
1989-01-01T23:59:59.000Z
: Dr. Jerry L. Machemehl The dynamic pressures acting on a I:5 scale recurved model seawall caused by breaking water waves were investigated. The magnitude, location and distribution of the shock and secondary pressures were determined from physical... and incident wave height increased, the magnitude of the shock and secondary pressure increased. Shock pressures as great as 3. 72 kN/m~ were recorded, while a change in water depth of 0. 01m caused a mean pressure increase of approximately 0. 09 k...
Large scale molecular dynamics modeling of materials fabrication processes
Belak, J.; Glosli, J.N.; Boercker, D.B.; Stowers, I.F.
1994-02-01T23:59:59.000Z
An atomistic molecular dynamics model of materials fabrication processes is presented. Several material removal processes are shown to be within the domain of this simulation method. Results are presented for orthogonal cutting of copper and silicon and for crack propagation in silica glass. Both copper and silicon show ductile behavior, but the atomistic mechanisms that allow this behavior are significantly different in the two cases. The copper chip remains crystalline while the silicon chip transforms into an amorphous state. The critical stress for crack propagation in silica glass was found to be in reasonable agreement with experiment and a novel stick-slip phenomenon was observed.
Li, Yangmin
robots [7]. A robust fuzzy logic controller was devised for a robotic manipulator with uncertainties [8Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving on a Slope 1 Dynamic Modeling and Adaptive Neural-Fuzzy Control for Nonholonomic Mobile Manipulators Moving
MODELLING RADIOIODINE DYNAMICS Modelling the Dynamics of Radioiodine in Dairy Cows
Crout, Neil
Department of Physiology & Environmental Science University of Nottingham Sutton Bonington LE12 5RD UK G for significant fecal excretion of radioiodine. The5 model is used to consider the effect of dietary stable iodine of iodine, in particular I-131, are important components in fallout from2 nuclear accidents
Integrated Canada-U.S. Power Sector Modeling with the Regional Energy Deployment System (ReEDS)
Martinez, A.; Eurek, K.; Mai, T.; Perry, A.
2013-02-01T23:59:59.000Z
The electric power system in North America is linked between the United States and Canada. Canada has historically been a net exporter of electricity to the United States. The extent to which this remains true will depend on the future evolution of power markets, technology deployment, and policies. To evaluate these and related questions, we modify the Regional Energy Deployment System (ReEDS) model to include an explicit representation of the grid-connected power system in Canada to the continental United States. ReEDS is unique among long-term capacity expansion models for its high spatial resolution and statistical treatment of the impact of variable renewable generation on capacity planning and dispatch. These unique traits are extended to new Canadian regions. We present example scenario results using the fully integrated Canada-U.S. version of ReEDS to demonstrate model capabilities. The newly developed, integrated Canada-U.S. ReEDS model can be used to analyze the dynamics of electricity transfers and other grid services between the two countries under different scenarios.
Ice sheets and their dynamics Continuum thermo-mechanical model of a glacier
Cerveny, Vlastislav
Ice sheets and their dynamics Continuum thermo-mechanical model of a glacier Shallow Ice Approximation (SIA) SIA-I Iterative Improvement Technique Benchmarks Numerical modeling of ice-sheet dynamics and Cartography, Zdiby 1.6.2010 Ondej Soucek Ph.D. defense #12;Ice sheets and their dynamics Continuum thermo
Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network
Johansen, Tor Arne
DS-06-1351 Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network TomÃ¡s dynamics of gasoline engines during transient operation. With a collection of input-output data measured;Modeling of Air-Fuel Ratio Dynamics of Gasoline Combustion Engine with ARX Network I. INTRODUCTION
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
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.2Â8 The main
Comparative Studies of Clustering Techniques for Real-Time Dynamic Model Reduction
Hogan, Emilie; Halappanavar, Mahantesh; Huang, Zhenyu; Lin, Guang; Lu, Shuai; Wang, Shaobu
2015-01-01T23:59:59.000Z
Dynamic model reduction in power systems is necessary for improving computational efficiency. Traditional model reduction using linearized models or offline analysis would not be adequate to capture power system dynamic behaviors, especially the new mix of intermittent generation and intelligent consumption makes the power system more dynamic and non-linear. Real-time dynamic model reduction emerges as an important need. This paper explores the use of clustering techniques to analyze real-time phasor measurements to determine generator groups and representative generators for dynamic model reduction. Two clustering techniques -- graph clustering and evolutionary clustering -- are studied in this paper. Various implementations of these techniques are compared and also compared with a previously developed Singular Value Decomposition (SVD)-based dynamic model reduction approach. Various methods exhibit different levels of accuracy when comparing the reduced model simulation against the original model. But some ...
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.
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.
Quantum Dynamics of the Driven and Dissipative Rabi Model
Loïc Henriet; Zoran Ristivojevic; Peter P. Orth; Karyn Le Hur
2014-08-15T23:59:59.000Z
The Rabi model considers a two-level system (or spin-1/2) coupled to a quantized harmonic oscillator and describes the simplest interaction between matter and light. The recent experimental progress in solid-state circuit quantum electrodynamics has engendered theoretical efforts to quantitatively describe the mathematical and physical aspects of the light-matter interaction beyond the rotating wave approximation. We develop a stochastic Schr\\"{o}dinger equation approach which enables us to access the strong-coupling limit of the Rabi model and study the effects of dissipation, and AC drive in an exact manner. We include the effect of ohmic noise on the non-Markovian spin dynamics resulting in Kondo-type correlations, as well as cavity losses. We compute the time evolution of spin variables in various conditions. As a consideration for future work, we discuss the possibility to reach a steady state with one polariton in realistic experimental conditions.
Examination of temporal DDT trends in Lake Erie fish communities using dynamic linear modeling
Arhonditsis, George B.
Examination of temporal DDT trends in Lake Erie fish communities using dynamic linear modeling 25 July 2013 Communicated by Dr. Erik Christensen Keywords: DDT Bayesian inference Dynamic linear (DDT) was initially heralded for its effectiveness against malaria and agricultural pests
Model Studies of the Dynamics of Bacterial Flagellar Motors
Bai, F; Lo, C; Berry, R; Xing, J
2009-03-19T23:59:59.000Z
The Bacterial Flagellar Motor is a rotary molecular machine that rotates the helical filaments which propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation and switching mechanism of the motor. In our previous paper, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here we further analyze this model. In this paper we show (1) the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with the latest experiment by Lo et al.; (2) with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, recently observed by Yuan and Berg; (3) the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwelling time distribution. Predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental verification.
The Dynamically Extended Mind -- A Minimal Modeling Case Study
Tom Froese; Carlos Gershenson; David A. Rosenblueth
2013-05-08T23:59:59.000Z
The extended mind hypothesis has stimulated much interest in cognitive science. However, its core claim, i.e. that the process of cognition can extend beyond the brain via the body and into the environment, has been heavily criticized. A prominent critique of this claim holds that when some part of the world is coupled to a cognitive system this does not necessarily entail that the part is also constitutive of that cognitive system. This critique is known as the "coupling-constitution fallacy". In this paper we respond to this reductionist challenge by using an evolutionary robotics approach to create a minimal model of two acoustically coupled agents. We demonstrate how the interaction process as a whole has properties that cannot be reduced to the contributions of the isolated agents. We also show that the neural dynamics of the coupled agents has formal properties that are inherently impossible for those neural networks in isolation. By keeping the complexity of the model to an absolute minimum, we are able to illustrate how the coupling-constitution fallacy is in fact based on an inadequate understanding of the constitutive role of nonlinear interactions in dynamical systems theory.
11.482J / 1.285J / ESD.193J Regional Socioeconomic Impact Analyses and Modeling, Fall 2003
Polenske, Karen R.
Reviews regional economic theories and models and provides students with experience in using alternative economic impact assessment models on microcomputers. Problem sets are oriented around infrastructure, housing, energy, ...
11.482J / 1.285J / ESD.193J Regional Socioeconomic Impact Analysis and Modeling, Fall 2006
Polenske, Karen
Reviews regional economic theories and models and provides students with experience in using alternative economic impact assessment models on microcomputers. Problem sets are oriented around infrastructure, housing, energy, ...
11.482J / 1.285J / ESD.193J Regional Socioeconomic Impact Analysis and Modeling, Fall 2004
Polenske, Karen R.
Reviews regional economic theories and models and provides students with experience in using alternative economic impact assessment models on microcomputers. Problem sets are oriented around infrastructure, housing, energy, ...
11.482J / 1.285J / ESD.193J Regional Socioeconomic Impact Analysis and Modeling, Fall 2005
Polenske, Karen R.
Reviews regional economic theories and models and provides students with experience in using alternative economic impact assessment models on microcomputers. Problem sets are oriented around infrastructure, housing, energy, ...
Chen, Yong
or applying an estimation method that is robust to the error structure assumption in modelling the dynamicsCan a more realistic model error structure improve the parameter estimation in modelling the dynamics of ®sh populations? Y. Chena,* , J.E. Paloheimob a Fisheries Conservation Chair Program, Fisheries
Ünver, Hakk? Özgür
2008-01-01T23:59:59.000Z
Scholars have developed a range of qualitative and quantitative models for generalizing the dynamics of technological innovation and identifying patterns of competition between rivals. This thesis compares two predominant ...
Coupling of Integrated Biosphere Simulator to Regional Climate Model version 3
Winter, Jonathan (Jonathan Mark)
2006-01-01T23:59:59.000Z
Presented in this thesis is a description of the coupling of Integrated Biosphere Simulator (IBIS) to Regional Climate Model version 3 (RegCM3), and an assessment of the coupled model (RegCM3-IBIS). RegCM3 is a 3-dimensional, ...
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.
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.
Dynamic first-order phase transition in kinetically constrained models of glasses
J. P. Garrahan; R. L. Jack; V. Lecomte; E. Pitard; K. van Duijvendijk; F. van Wijland
2007-05-22T23:59:59.000Z
We show that the dynamics of kinetically constrained models of glass formers takes place at a first-order coexistence line between active and inactive dynamical phases. We prove this by computing the large-deviation functions of suitable space-time observables, such as the number of configuration changes in a trajectory. We present analytic results for dynamic facilitated models in a mean-field approximation, and numerical results for the Fredrickson-Andersen model, the East model, and constrained lattice gases, in various dimensions. This dynamical first-order transition is generic in kinetically constrained models, and we expect it to be present in systems with fully jammed states.
Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.; Johnson, Gary E.
2005-03-10T23:59:59.000Z
Computational fluid dynamics (CFD) models were developed to support the siting and design of a behavioral guidance system (BGS) structure in The Dalles Dam (TDA) forebay on the Columbia River. The work was conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District (CENWP). The CFD results were an invaluable tool for the analysis, both from a Regional and Agency perspective (for the fish passage evaluation) and a CENWP perspective (supporting the BGS design and location). The new CFD model (TDA forebay model) included the latest bathymetry (surveyed in 1999) and a detailed representation of the engineered structures (spillway, powerhouse main, fish, and service units). The TDA forebay model was designed and developed in a way that future studies could easily modify or, to a large extent, reuse large portions of the existing mesh. This study resulted in these key findings: (1) The TDA forebay model matched well with field-measured velocity data. (2) The TDA forebay model matched observations made at the 1:80 general physical model of the TDA forebay. (3) During the course of this study, the methodology typically used by CENWP to contour topographic data was shown to be inaccurate when applied to widely-spaced transect data. Contouring methodologies need to be revisited--especially before such things as modifying the bathymetry in the 1:80 general physical model are undertaken. Future alignments can be evaluated with the model staying largely intact. The next round of analysis will need to address fish passage demands and navigation concerns. CFD models can be used to identify the most promising locations and to provide quantified metrics for biological, hydraulic, and navigation criteria. The most promising locations should then be further evaluated in the 1:80 general physical model.
Short communication Dynamics of a model of two delay-coupled relaxation oscillators
Rand, Richard H.
: Coupled oscillators Devil's Staircase Delay-differential equations a b s t r a c t This paper investigates by regions of complicated dynamics, reminiscent of the Devil's Staircase. Stability of motions in the in
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
Dynamic Code Overlay of SDF-Modeled Programs on Low-end Embedded Systems
Ha, Soonhoi
Dynamic Code Overlay of SDF-Modeled Programs on Low-end Embedded Systems Hae-woo Park Kyoungjoo Oh of synchronous data-flow (SDF) Âmodeled program for low-end embedded systems which lack MMU- support-program code, dynamic loader and linker script files from the given SDF- modeled blocks and schematic, so we
Capacitive effect of cavitation in xylem conduits: results from a dynamic model
Mencuccini, Maurizio
Capacitive effect of cavitation in xylem conduits: results from a dynamic model TEEMU HÃ?LTTÃ?1. A dynamic model is presented that models xylem water potential, xylem sap flow and cavitation, taking; xylem transport. INTRODUCTION Xylem embolism formation by cavitation causes a decrease in plant
Lateral Dynamics Reconstruction for Sharp'71 Motorcycle Model with P2I Observer
Paris-Sud XI, UniversitÃ© de
Lateral Dynamics Reconstruction for Sharp'71 Motorcycle Model with P2I Observer Chabane Chenane (motorcycle, scooter, etc.). For that purpose, the well-known motorcycle model developed by Sharp in 1971 is used. This model characterizes the lateral dynamics of a motorcycle [16]. The roll angle
Dynamical Formation of the Dark Molecular Hydrogen Clouds around Diffuse HII Regions
Takashi Hosokawa; Shu-ichiro Inutsuka
2007-04-05T23:59:59.000Z
We examine the triggering process of molecular cloud formation around diffuse HII regions. We calculate the time evolution of the shell as well as of the HII region in a two-phase neutral medium, solving the UV and FUV radiative transfer, the thermal and chemical processes in the time-dependent hydrodynamics code. In the cold neutral medium, the ambient gas is swept up in the cold (T \\sim 30-40K) and dense (n \\sim 10^3 cm^-3) shell around the HII region. In the shell, H_2 molecules are formed from the swept-up HI gas, but CO molecules are hardly formed. The reformation of H_2 molecules is more efficient with a higher-mass central star. The physical and chemical properties of gas in the shell are just intermediate between those of the neutral medium and molecular clouds observed by the CO emission. The dense shell with cold HI/H_2 gas easily becomes gravitationally unstable, and breaks up into small clouds. The cooling layer just behind the shock front also suffers from thermal instability, and will fragment into cloudlets with some translational motions. We suggest that the predicted cold ``dark'' HI/H_2 gas should be detected as the HI self-absorption (HISA) feature. We have sought such features in recent observational data, and found shell-like HISA features around the giant HII regions, W4 and W5. The shell-like HISA feature shows good spatial correlation with dust emission, but poor correlation with CO emission. Our quantitative analysis shows that the HISA cloud can be as cold as T \\sim a few x 10K. (abridged)
Tyre modelling for use in vehicle dynamics studies
Bakker, E.; Nyborg, L.; Pacejka, H.B.
1987-01-01T23:59:59.000Z
A new way of representing tyre data obtained from measurements in pure cornering and pure braking conditions has been developed in order to further improve the Dynamic Safety of vehicles. The method makes use of a formula with coefficients which describe some of the typifying quantities of a tyre, such as slip stiffnesses at zero slip and force and torque peak values. The formula is capable of describing the characteristics of side force, brake force and self aligning torque with great accuracy. This mathematical representation is limited to steady-state conditions during either pure cornering or pure braking and forms the basis for a model describing tyre behaviour during combined braking and cornering.
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.
Dynamic Markov bridges motivated by models of insider trading
Campi, Luciano; Danilova, Albina
2012-01-01T23:59:59.000Z
Given a Markovian Brownian martingale $Z$, we build a process $X$ which is a martingale in its own filtration and satisfies $X_1 = Z_1$. We call $X$ a dynamic bridge, because its terminal value $Z_1$ is not known in advance. We compute explicitly its semimartingale decomposition under both its own filtration $\\cF^X$ and the filtration $\\cF^{X,Z}$ jointly generated by $X$ and $Z$. Our construction is heavily based on parabolic PDE's and filtering techniques. As an application, we explicitly solve an equilibrium model with insider trading, that can be viewed as a non-Gaussian generalization of Back and Pedersen's \\cite{BP}, where insider's additional information evolves over time.
The Dynamics of Deterministic Chaos in Numerical Weather Prediction Models
A. Mary Selvam
2003-10-07T23:59:59.000Z
Atmospheric weather systems are coherent structures consisting of discrete cloud cells forming patterns of rows/streets, mesoscale clusters and spiral bands which maintain their identity for the duration of their appreciable life times in the turbulent shear flow of the planetary Atmospheric Boundary Layer. The existence of coherent structures (seemingly systematic motion) in turbulent flows has been well established during the last 20 years of research in turbulence. Numerical weather prediction models based on the inherently non-linear Navier-Stokes equations do not give realistic forecasts because of the following inherent limitations: (1) the non-linear governing equations for atmospheric flows do not have exact analytic solutions and being sensitive to initial conditions give chaotic solutions characteristic of deterministic chaos (2) the governing equations do not incorporate the dynamical interactions and co-existence of the complete spectrum of turbulent fluctuations which form an integral part of the large coherent weather systems (3) limitations of available computer capacity necessitates severe truncation of the governing equations, thereby generating errors of approximations (4) the computer precision related roundoff errors magnify the earlier mentioned uncertainties exponentially with time and the model predictions become unrealistic. The accurate modelling of weather phenomena therefore requires alternative concepts and computational techniques. In this paper a universal theory of deterministic chaos applicable to the formation of coherent weather structures in the ABL is presented.
Estimation of Parameterized Spatio-Temporal Dynamic Models Ke Xu and Christopher K. Wikle
Estimation of Parameterized Spatio-Temporal Dynamic Models Ke Xu and Christopher K. Wikle: Christopher K. Wikle, Department of Statistics, University of Missouri, 146 Math Science Building, Columbia
Kim, Min-Cheol
An integrative cell migration model incorporating focal adhesion (FA) dynamics, cytoskeleton and nucleus remodeling, actin motor activity, and lamellipodia protrusion is developed for predicting cell spreading and migration ...
Modeling Long-Term Landscape Dynamics and the Emergence of Intensification
interactions between agricultural practices and landscape change for the Mediterranean Basin. Here, we report the recursive interactions between social landuse decisions, climate change, and landscape dynamics at regional scales. The Mediterranean Landscape Dynamics project, along with a handful of other ongoing projects
Huang, Hsin-Yuan; Hall, Alex
2013-07-24T23:59:59.000Z
Stratocumulus and shallow cumulus clouds in subtropical oceanic regions (e.g., Southeast Pacific) cover thousands of square kilometers and play a key role in regulating global climate (e.g., Klein and Hartmann, 1993). Numerical modeling is an essential tool to study these clouds in regional and global systems, but the current generation of climate and weather models has difficulties in representing them in a realistic way (e.g., Siebesma et al., 2004; Stevens et al., 2007; Teixeira et al., 2011). While numerical models resolve the large-scale flow, subgrid-scale parameterizations are needed to estimate small-scale properties (e.g. boundary layer turbulence and convection, clouds, radiation), which have significant influence on the resolved scale due to the complex nonlinear nature of the atmosphere. To represent the contribution of these fine-scale processes to the resolved scale, climate models use various parameterizations, which are the main pieces in the model that contribute to the low clouds dynamics and therefore are the major sources of errors or approximations in their representation. In this project, we aim to 1) improve our understanding of the physical processes in thermal circulation and cloud formation, 2) examine the performance and sensitivity of various parameterizations in the regional weather model (Weather Research and Forecasting model; WRF), and 3) develop, implement, and evaluate the advanced boundary layer parameterization in the regional model to better represent stratocumulus, shallow cumulus, and their transition. Thus, this project includes three major corresponding studies. We find that the mean diurnal cycle is sensitive to model domain in ways that reveal the existence of different contributions originating from the Southeast Pacific land-masses. The experiments suggest that diurnal variations in circulations and thermal structures over this region are influenced by convection over the Peruvian sector of the Andes cordillera, while the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain. According to our experiments, the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer scheme and the WSM6 microphysics scheme is the combination of schemes that performs best. For that combination, mean cloud cover, liquid water path, and cloud depth are fairly wellsimulated, while mean cloud top height remains too low in comparison to observations. Both microphysics and boundary layer schemes contribute to the spread in liquid water path and cloud depth, although the microphysics contribution is slightly more prominent. Boundary layer schemes are the primary contributors to cloud top height, degree of adiabaticity, and cloud cover. Cloud top height is closely related to surface fluxes and boundary layer structure. Thus, our study infers that an appropriate tuning of cloud top height would likely improve the low-cloud representation in the model. Finally, we show that entrainment governs the degree of adiabaticity, while boundary layer decoupling is a control on cloud cover. In the intercomparison study using WRF single-column model experiments, most parameterizations show a poor agreement of the vertical boundary layer structure when compared with large-eddy simulation models. We also implement a new Total-Energy/Mass- Flux boundary layer scheme into the WRF model and evaluate its ability to simulate both stratocumulus and shallow cumulus clouds. Result comparisons against large-eddy simulation show that this advanced parameterization based on the new Eddy-Diffusivity/Mass-Flux approach provides a better performance than other boundary layer parameterizations.
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.
Calibration of Reduced Dynamic Models of Power Systems using Phasor Measurement Unit (PMU) Data
Zhou, Ning; Lu, Shuai; Singh, Ruchi; Elizondo, Marcelo A.
2011-09-23T23:59:59.000Z
Accuracy of a power system dynamic model is essential to the secure and efficient operation of the system. Lower confidence on model accuracy usually leads to conservative operation and lowers asset usage. To improve model accuracy, identification algorithms have been developed to calibrate parameters of individual components using measurement data from staged tests. To facilitate online dynamic studies for large power system interconnections, this paper proposes a model reduction and calibration approach using phasor measurement unit (PMU) data. First, a model reduction method is used to reduce the number of dynamic components. Then, a calibration algorithm is developed to estimate parameters of the reduced model. This approach will help to maintain an accurate dynamic model suitable for online dynamic studies. The performance of the proposed method is verified through simulation studies.
Shell Model Dynamics of HCl on the MgO(001) Surface Terrace Andreas Markmann,1
Markmann, Andreas
are then used to aid the analysis of MD calculations. After equilibrium dynamics, a sudden excitation of the OH of molecular dynamics using specially tailored laser fields. The reaction of hydrogen chloride moleculesShell Model Dynamics of HCl on the MgO(001) Surface Terrace Andreas Markmann,1 Jacob L. Gavartin,2
Idealized test cases for the dynamical cores of Atmospheric General Circulation Models
Jablonowski, Christiane
Idealized test cases for the dynamical cores of Atmospheric General Circulation Models: A proposal) Ram Nair (NCAR) Mark Taylor (Sandia National Laboratory) May/29/2008 1 Idealized test cases for 3D dynamical cores This document describes the idealized dynamical core test cases that are proposed
Physica D 159 (2001) 3557 Wave group dynamics in weakly nonlinear long-wave models
Pelinovsky, Dmitry
Physica D 159 (2001) 35Â57 Wave group dynamics in weakly nonlinear long-wave models Roger Grimshawa Communicated by A.C. Newell Abstract The dynamics of wave groups is studied for long waves, using the framework reserved. Keywords: Wave group dynamics; KortewegÂde Vries equation; Nonlinear SchrÂ¨odinger equation 1
High-resolution observations of active region moss and its dynamics
Morton, R J
2014-01-01T23:59:59.000Z
The \\textit{High resolution Coronal Imager (Hi-C)} has provided the sharpest view of the EUV corona to date. In this paper we exploit its impressive resolving power to provide the first analysis of the fine-scale structure of moss in an active region. The data reveal that the moss is made up of a collection of fine threads, that have widths with a mean and standard deviation of $440\\pm190$~km (Full Width Half Maximum). {The brightest moss emission is located at the visible head of the fine-scale structure and the fine structure appears to extend into the lower solar atmosphere.} The emission decreases along the features implying the lower sections are most likely dominated by cooler transition region plasma. These threads appear to be the cool, lower legs of the hot loops. In addition, the increased resolution allows for the first direct observation {of physical displacements of the moss fine-structure in a direction transverse to its central axis. Some of these transverse displacements demonstrate periodic b...
Locatelli, R.
A modelling experiment has been conceived to assess the impact of transport model errors on methane emissions estimated in an atmospheric inversion system. Synthetic methane observations, obtained from 10 different model ...
Incorporating Stakeholder Decision Support Needs into an Integrated Regional Earth System Model
Rice, Jennie S.; Moss, Richard H.; Runci, Paul J.; Anderson, K. L.; Malone, Elizabeth L.
2012-03-21T23:59:59.000Z
A new modeling effort exploring the opportunities, constraints, and interactions between mitigation and adaptation at regional scale is utilizing stakeholder engagement in an innovative approach to guide model development and demonstration, including uncertainty characterization, to effectively inform regional decision making. This project, the integrated Regional Earth System Model (iRESM), employs structured stakeholder interactions and literature reviews to identify the most relevant adaptation and mitigation alternatives and decision criteria for each regional application of the framework. The information is used to identify important model capabilities and to provide a focus for numerical experiments. This paper presents the stakeholder research results from the first iRESM pilot region. The pilot region includes the Great Lakes Basin in the Midwest portion of the United States as well as other contiguous states. This geographic area (14 states in total) permits cohesive modeling of hydrologic systems while also providing gradients in climate, demography, land cover/land use, and energy supply and demand. The results from the stakeholder research indicate that iRESM should prioritize addressing adaptation alternatives in the water resources, urban infrastructure, and agriculture sectors, such as water conservation, expanded water quality monitoring, altered reservoir releases, lowered water intakes, urban infrastructure upgrades, increased electric power reserves in urban areas, and land use management/crop selection changes. Regarding mitigation alternatives, the stakeholder research shows a need for iRESM to focus on policies affecting the penetration of renewable energy technologies, and the costs and effectiveness of energy efficiency, bioenergy production, wind energy, and carbon capture and sequestration.
Georgia, University of
Models, Modeling Dynamic Systems, DOI 10.1007/978-1-4614-1257-1_7, Â© Springer Science+Business Media, LLC, these targets should represent the most efficient use of limited resources, especially given that resource managers need to balance multiple, often complex issues (Reed et al. 2009). Population models can often aid
A spatially structured metapopulation model with patch dynamics
2007-08-22T23:59:59.000Z
Sep 30, 2005 ... creation) and metapopulation dynamics (patch colonization and extinction). ... genetic structure (Gaines and Lyons, 1997), and commu-.
Regional Modeling of Dust Mass Balance and Radiative Forcing over East Asia using WRF-Chem
Chen, Siyu; Zhao, Chun; Qian, Yun; Leung, Lai-Yung R.; Huang, J.; Huang, Zhongwei; Bi, Jianrong; Zhang, Wu; Shi, Jinsen; Yang, Lei; Li, Deshuai; Li, Jinxin
2014-12-01T23:59:59.000Z
The Weather Research and Forecasting model with Chemistry (WRF-Chem) is used to investigate the seasonal and annual variations of mineral dust over East Asia during 2007-2011, with a focus on the dust mass balance and radiative forcing. A variety of measurements from in-stu and satellite observations have been used to evaluate simulation results. Generally, WRF-Chem reproduces not only the column variability but also the vertical profile and size distribution of mineral dust over and near the dust source regions of East Asia. We investigate the dust lifecycle and the factors that control the seasonal and spatial variations of dust mass balance and radiative forcing over the seven sub-regions of East Asia, i.e. source regions, the Tibetan Plateau, Northern China, Southern China, the ocean outflow region, and Korea-Japan regions. Results show that, over the source regions, transport and dry deposition are the two dominant sinks. Transport contributes to ~30% of the dust sink over the source regions. Dust results in a surface cooling of up to -14 and -10 W m-2, atmospheric warming of up to 20 and 15 W m-2, and TOA cooling of -5 and -8 W m-2 over the two major dust source regions of East Asia, respectively. Over the Tibetan Plateau, transport is the dominant source with a peak in summer. Over identified outflow regions, maximum dust mass loading in spring is contributed by the transport. Dry and wet depositions are the comparably dominant sinks, but wet deposition is larger than dry deposition over the Korea-Japan region, particularly in spring (70% versus 30%). The WRF-Chem simulations can generally capture the measured features of dust aerosols and its radaitve properties and dust mass balance over East Asia, which provides confidence for use in further investigation of dust impact on climate over East Asia.
Pion photoproduction in a dynamical coupled-channels model
Huang, F; Haberzettl, H; Haidenbauer, J; Hanhart, C; Krewald, S; ner, U -G Meiß; Nakayama, K
2011-01-01T23:59:59.000Z
The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, and Nakayama [Phys. Rev. C 83, 065502 (2011)]. The hadronic final-state interaction is provided by the Juelich pi-N model, which includes the channels pi-N and eta-N comprising stable hadrons as well as the effective pi-pi-N channels pi-Delta, sigma-N, and rho-N. This hadronic model has been quite successful in describing pi-N to pi-N scattering for center-of-mass energies up to 1.9 GeV. By construction, the full pion photoproduction current satisfies the generalized Ward-Takahashi identity and thus is gauge invariant as a matter of course. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions gamma p to pi+ n, gamma p to pi0 p, gamma n to pi- p and gamma n to pi0 n are in good agreement with the experimental data.
Pion photoproduction in a dynamical coupled-channels model
F. Huang; M. Döring; H. Haberzettl; J. Haidenbauer; C. Hanhart; S. Krewald; U. -G. Meiß ner; K. Nakayama
2011-10-17T23:59:59.000Z
The charged and neutral pion photoproduction reactions are investigated in a dynamical coupled-channels approach based on the formulation of Haberzettl, Huang, and Nakayama [Phys. Rev. C 83, 065502 (2011)]. The hadronic final-state interaction is provided by the Juelich pi-N model, which includes the channels pi-N and eta-N comprising stable hadrons as well as the effective pi-pi-N channels pi-Delta, sigma-N, and rho-N. This hadronic model has been quite successful in describing pi-N to pi-N scattering for center-of-mass energies up to 1.9 GeV. By construction, the full pion photoproduction current satisfies the generalized Ward-Takahashi identity and thus is gauge invariant as a matter of course. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions gamma p to pi+ n, gamma p to pi0 p, gamma n to pi- p and gamma n to pi0 n are in good agreement with the experimental data.
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
Time series analysis of regional climate model performance Jason P. Evans
Evans, Jason
in Kansas, United States, including the First International Satellite Land Surface Climatology Project, both regional and global, has become apparent. Predictions of the energy and water balance to evapotranspiration and fails to close the energy budget. All of the models overestimate runoff and evapotranspiration
A MODIFIED GAMBLER'S RUIN MODEL POLYETHYLENE CHAINS IN THE AMORPHOUS REGION
Aluffi, Paolo
A MODIFIED GAMBLER'S RUIN MODEL OF POLYETHYLENE CHAINS IN THE AMORPHOUS REGION ZhongÂHui Duan and Louis N. Howard Department of Mathematics The Florida State University ABSTRACT. Polyethylene chainsM 3 +O(M 2 ). INTRODUCTION Semicrystalline polyethylene formed from melt generally consists
A Multi-Model Assessment of Regional Climate Disparities Caused by Solar Geoengineering
Robock, Alan
1 A Multi-Model Assessment of Regional Climate Disparities Caused by Solar Geoengineering Normal University, Beijing, China. 9 School of Engineering and Applied Sciences, Harvard University levels. G1 involves a reduction in solar irradiance to counteract the radiative forcing5 in abrupt4xCO2
REGION-BASED ACTIVE SURFACE MODELLING AND ALPHA MATTING FOR UNSUPERVISED TUMOUR SEGMENTATION IN PET
Wang, Jue
REGION-BASED ACTIVE SURFACE MODELLING AND ALPHA MATTING FOR UNSUPERVISED TUMOUR SEGMENTATION IN PET University, UK. 3. Adobe Systems, Seattle, USA. 4. Turku PET Center and Department of Oncology imaging. We have validated our method on real PET images of head-and-neck cancer patients as well
Biophysical modeling of NO emissions from agricultural soils for use in regional
Boyer, Edmond
Biophysical modeling of NO emissions from agricultural soils for use in regional chemistry-transport and12 crop management practices, along with the resolution of the climate and soil input maps.13 14 and agronomic factors, including cropping practices, soil characteristics and cli-17 mate. Crop management
Influence of spatial resolution on regional climate model derived wind climates
Pryor, Sara C.
of northern Europe is more profound in the wind extremes than in the central tendency. The domain are of similar magnitude to the climate change signal in extreme wind events derived in prior research and mayInfluence of spatial resolution on regional climate model derived wind climates S. C. Pryor,1 G
Menut, Laurent
is dedicated to regional atmospheric pollution event studies. Since it has now reached a certain level atmospheric composition modelling Laurent MENUT1 , Bertrand BESSAGNET2 , Dmitry KHVOROSTYANOV1 , Matthias dell'Aquila, L'Aquila, Italy 6 NCAR Atmospheric Chemistry Division, 3450 Mitchell Lane, Boulder
Optimal foreign borrowing in a multisector dynamic equilibrium model for Brazil
Tourinho, Octv?io A. F.
1985-01-01T23:59:59.000Z
This paper shows how a dynamic multisector equilibrium model can be formulated to be able to analyze the optimal borrowing policy of a developing country. It also describes how a non-linear programming model with the ...
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 ...
Rojas Paico, Danny H.
2001-01-01T23:59:59.000Z
Into Reservoir Models. (Decmnber 200 I) Danny LL Rojas Paico, B. S. , Universidad Nacional de Ingenieria, Peru Chair of Advisory Committee: Dr. Akhil Datta-Gupta The integration of dynamic data into reservoir models is known as automatic history matching...
Evolutionary Processes in Economics: Multi-agent Model of Macrogenerations Dynamics
LÃ³pez-SÃ¡nchez, Maite
Evolutionary Processes in Economics: Multi-agent Model of Macrogenerations Dynamics Kateryna macroeconomic growth as an evolutionary process. Keywords. Economic growth, evolutionary theory, multi]. Our study models the economic growth as an evolutionary process, where the term `macrogeneration
age-structured dynamical models: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
does not migrate. Le, Thuc Manh; Van Minh, Nguyen 2010-01-01 36 Galactic Nonlinear Dynamic Model Mathematical Physics (arXiv) Summary: We develop a model for spiral galaxies...
Griffith, Daniel Todd
2005-02-17T23:59:59.000Z
equations, for a class of nonlinear dynamical systems. In the area of trajectory optimization some new ideas are presented for automating the process of deriving co- state differential equations. Additionally, higher-order algorithms for computing... midcourse corrections are introduced. In Chapter IV, some new insights into modeling of dynamical systems are presented. Producing dynamical models in the form of coupled nonlinear differential equations is a frequent first step for analysis, estimation...
Yurchyshyn, Vasyl; Kilcik, Ali
2014-01-01T23:59:59.000Z
We analyse sunspot oscillations using Interface Region Imaging Spectrograph (IRIS) slit-jaw and spectral data and narrow-band chromospheric images from the New Solar Telescope (NST) for the main sunspot in NOAA AR 11836. We report that the difference between the shock arrival times as measured the Mg II k 2796.35\\AA\\ and Si IV 1393.76\\AA\\ line formation levels changes during the observed period and peak-to-peak delays may range from 40~s to zero. The intensity of chromospheric shocks also displays a long term (about 20~min) variations. NST's high spatial resolution \\ha\\ data allowed us to conclude that in this sunspot umbral flashes (UFs) appeared in the form of narrow bright lanes stretched along the light bridges and around clusters of umbral bright points. Time series also suggested that UFs preferred to appear on the sunspot-center side of light bridges, which may indicate the existence of a compact sub-photospheric driver of sunspot oscillations. The sunspot's umbra as seen in the IRIS chromospheric and ...
Denny, Mark
Currents and turbulence within a kelp forest (Macrocystis pyrifera): Insights from a dynamically a dynamically matched 1/25-scale model. Two kelp configurations with surface canopies and one without a surface acoustic Doppler velocimeters. Since flow within the model kelp forest was very heterogeneous, spatially
NUMERICAL MODELING OF SHOCK-INDUCED DAMAGE FOR GRANITE UNDER DYNAMIC LOADING
Stewart, Sarah T.
NUMERICAL MODELING OF SHOCK-INDUCED DAMAGE FOR GRANITE UNDER DYNAMIC LOADING H. A. Ai1 , T. J beneath impact crater in granite. Model constants are determined either directly from static uniaxial from Century Dynamics to simulate the shock-induced damage in granite targets impacted by projectiles
Dynamic Versus Steady-State Modeling of FACTS Controllers in Transmission Congestion
CaÃ±izares, Claudio A.
benchmark system is used to illustrate and compare the effect on locational marginal prices and transmission marginal prices obtained from stability-constrained auction models when dynamic and steady state FACTS discusses the effect on transmission congestion management and pricing of dynamic and steady- state models
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
A model for dynamic chance constraints in hydro power reservoir management
Römisch, Werner
A model for dynamic chance constraints in hydro power reservoir management L. Andrieu , R. Henrion In this paper, a model for (joint) dynamic chance constraints is proposed and ap- plied to an optimization for two and three stages. 1 Introduction A conventional optimization problem under chance constraints
Development of a Dynamic Model of a Small High-Speed Autonomous Underwater Vehicle
Virginia Tech
Development of a Dynamic Model of a Small High-Speed Autonomous Underwater Vehicle Haider N. Arafat-- A dynamic model is developed for a small, high- speed autonomous underwater vehicle. The vehicle has manner: 1) Wind angle and angle : From u = V cos , v = V sin sin , and w = V sin cos , we have tan
A Numerical Model for the Dynamic Simulation of a Recirculation Single-Effect Absorption Chiller
Paris-Sud XI, UniversitÃ© de
A Numerical Model for the Dynamic Simulation of a Recirculation Single- Effect Absorption Chiller A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller is developed. The chiller is driven by two distinct heat sources, includes a custom integrated falling film
STOCHASTIC COMPUTATIONAL DYNAMICAL MODEL OF UNCERTAIN STRUCTURE COUPLED WITH AN INSULATION LAYER
Boyer, Edmond
STOCHASTIC COMPUTATIONAL DYNAMICAL MODEL OF UNCERTAIN STRUCTURE COUPLED WITH AN INSULATION LAYER the effect of insulation layers in complex dynamical systems for low- and medium-frequency ranges such as car booming noise analysis, one introduces a sim- plified stochastic model of insulation layers based
Dynamic Optimization in Continuous-Time Economic Models (A Guide for the Perplexed)
Sadoulet, Elisabeth
Dynamic Optimization in Continuous-Time Economic Models (A Guide for the Perplexed) Maurice, continuous-time modeling allows application of a powerful mathematical tool, the theory of optimal dynamic control. The basic idea of optimal control theory is easy to grasp-- indeed it follows from elementary
Bierlaire, Michel
A differentiable dynamic network loading model that yields queue length distributions and accounts, this is so because the kinematic wave model (KWM), the mainstay of traffic flow theory, only applies for spillback Carolina Osorio Gunnar FlÂ¨otterÂ¨od Michel Bierlaire Abstract We derive a dynamic network
Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model
Paris-Sud XI, UniversitÃ© de
Filtering Noisy ECG Signals Using the Extended Kalman Filter Based on a Modified Dynamic ECG Model for the filtering of noisy ECG signals. The method is based on a modified nonlinear dynamic model, previously introduced for the generation of synthetic ECG signals. An automatic parameter selection method has also been
ECG Denoising Using a Dynamical Model and a Marginalized Particle Filter
Tourneret, Jean-Yves
ECG Denoising Using a Dynamical Model and a Marginalized Particle Filter Chao Lin1,3, M of robust ECG denoising tech- niques is important for automatic diagnoses of cardiac diseases. Based on a previously suggested nonlinear dynamic model for the generation of realistic synthetic ECG, we introduce
Wetland model in an earth systems modeling framework for regional environmental policy analysis
Awadalla, Sirein Salah
2011-01-01T23:59:59.000Z
The objective of this research is to investigate incorporating a wetland component into a land energy and water fluxes model, the Community Land Model (CLM). CLM is the land fluxes component of the Integrated Global Systems ...
Kier, R.S.; Showalter, P.A.; Dettinger, M.D.
1980-05-30T23:59:59.000Z
Disposal of high-level radioactive wastes is a major environmental problem influencing further development of nuclear energy in this country. Salt domes in the Gulf Coast Basin are being investigated as repository sites. A major concern is geologic and hydrologic stability of candidate domes and potential transport of radionuclides by groundwater to the biosphere prior to their degradation to harmless levels of activity. This report conceptualizes a regional geohydrologic model for transport of radionuclides from a salt dome repository. The model considers transport pathways and the physical and chemical changes that would occur through time prior to the radionuclides reaching the biosphere. Necessary, but unknown inputs to the regional model involve entry and movement of fluids through the repository dome and across the dome-country rock interface and the effect on the dome and surrounding strata of heat generated by the radioactive wastes.
Two-dimensional modeling of apparent resistivity pseudosections in the Cerro Prieto region
Vega, R.; Martinez, M.
1981-01-01T23:59:59.000Z
Using a finite-difference program (Dey, 1976) for two-dimensional modeling of apparent resistivity pseudosections obtained by different measuring arrays, four apparent resistivity pseudosections obtained at Cerro Prieto with a Schlumberger array by CFE personnel were modeled (Razo, 1978). Using geologic (Puente and de la Pena, 1978) and lithologic (Diaz, et al., 1981) data from the geothermal region, models were obtained which show clearly that, for the actual resistivity present in the zone, the information contained in the measured pseudosections is primarily due to the near-surface structure and does not show either the presence of the geothermal reservoir or the granitic basement which underlies it.
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...
Agarwal, Pratul K.
2013-04-09T23:59:59.000Z
A method for analysis, control, and manipulation for improvement of the chemical reaction rate of a protein-mediated reaction is provided. Enzymes, which typically comprise protein molecules, are very efficient catalysts that enhance chemical reaction rates by many orders of magnitude. Enzymes are widely used for a number of functions in chemical, biochemical, pharmaceutical, and other purposes. The method identifies key protein vibration modes that control the chemical reaction rate of the protein-mediated reaction, providing identification of the factors that enable the enzymes to achieve the high rate of reaction enhancement. By controlling these factors, the function of enzymes may be modulated, i.e., the activity can either be increased for faster enzyme reaction or it can be decreased when a slower enzyme is desired. This method provides an inexpensive and efficient solution by utilizing computer simulations, in combination with available experimental data, to build suitable models and investigate the enzyme activity.
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.
Integrated dynamic landscape analysis and modeling system (IDLAMS) : programmer's manual.
Klaus, C. M.; 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.
The modeling of aerosol dynamics during degraded core events
Clausse, A.; Lahey, R.T. Jr.
1989-01-01T23:59:59.000Z
There is substantial interest in developing simple, yet accurate, models for the prediction of aerosol dynamics during degraded core events. The exact aerosol transport equation is given by {partial derivative}n(v,t)/{partial derivative}t = 1/2 {integral}{sub 0}{sup {infinity}} K(u,v {minus} u)n(u,t)n(v {minus} u,t)du {minus} {integral}{sub 0}{sup {infinity}} K(u,v)n(v,t)n(u,t)du {minus} n(v,t)c(v)/h + n{sub p}(v), where n(v,t) is the particle size density distribution function. The kernel, K(v,u), is related to the frequency of coagulation between aerosol particles of volume u and v, and the quantity c(v) is the deposition velocity. The quantity h is the effective height for deposition of aerosol; it is the volume of the aerosol cloud divided by the projected horizontal area A. Finally, the term n{sub p} (v) is the source rate of aerosol. Evaluation of the above equation is discussed.
Dynamics of an age-structured metapopulation model
2005-10-28T23:59:59.000Z
address the temporal dynamics that characterize local popu- lations in ... this metapopulation framework, two structures have emerged as being critical in the ...
Mountziaris, T. J.
models to describe adsorption dynamics Â· Apply to case of Enhanced Coalbed Methane Extraction Â Trillions of cubic meters of methane and carbon dioxide can be extracted and stored in unusable coal seams Models temperature, adsorption increases with pressure. Carbon Dioxide interacts more strongly with coal than methane
A Business Model Framework for Dynamic Spectrum Access in Cognitive Networks
Ha, Dong S.
A Business Model Framework for Dynamic Spectrum Access in Cognitive Networks Nikhil Kelkar, Dr implement these technologies and still profit from them? III. FUNDAMENTAL MODEL The business model which we a multi-parameter approach by defining four levels on which everyday business models operate. Value
BIOMECHANICAL ANALYSIS OF TWO SIMPLE DYNAMICAL MODELS FOR THE HUMAN GAIT
Llanos, Diego R.
and expenditure energy for the human body in normal walking models. Both models allow us to adapt a vector the adaptability of the subject to the environment in a reactive way . The high complexity of biomechanical modelsBIOMECHANICAL ANALYSIS OF TWO SIMPLE DYNAMICAL MODELS FOR THE HUMAN GAIT J.Finat1 , F.Montoya2
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
A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic of multi-megawatt turbines requires a new generation of modeling capability to assess individual turbine. Key Result The work is generating several models, including actuator line models of several wind
Banbara, Mutsunori
_n is blow m. Â e.g. m=5 : No (3,3) / Yes (4,1) #12;Multi-Objective Max-CSP (Properties) For a cost vector RModeling and Algorithm for DynamicModeling and Algorithm for Dynamic Multi-Objective Max-CSPsMulti-Objective Max-CSPs Tenda Okimoto Â¹Â², Tony Rebeiro Â³, Maxime Clement and Katsumi Inoue Â² Â¹ Transdisciplinary
Exact solution of the van der Waals model in the critical region
Adriano Barra; Antonio Moro
2014-12-05T23:59:59.000Z
Inspired by the theory of nonlinear conservation laws, we propose a novel approach, in the framework of statistical mechanics, that naturally extends the van der Waals model to the critical region. Starting from an effective microscopic description, we derive the general functional form of its mean field partition function under the assumption named Isochoric Weights Thermodynamic ansatz. The condition that outside the critical region the model reproduces, in the thermodynamic limit, the classical van der Waals equation of state allows to fix uniquely the partition function. We show that isothermal curves develop a classical viscous shock which provides the exact analytical description of the first order gas-liquid transition of simple fluids. The solution obtained holds for finite number of particles and, in the thermodynamic limit, automatically encodes the Maxwell equal areas rule.
E-Print Network 3.0 - andes region Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
dynamics and precipitation. We present experiments in which Andean... Uplift South America Regional modeling Andes 1 Introduction Large, mid-latitude mountain......
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.
Wang, Hesheng, E-mail: hesheng@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Feng, Mary [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Frey, Kirk A. [Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Ten Haken, Randall K.; Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Cao, Yue [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan (United States); Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan (United States)
2013-08-01T23:59:59.000Z
Purpose: High-dose radiation therapy (RT) for intrahepatic cancer is limited by the development of liver injury. This study investigated whether regional hepatic function assessed before and during the course of RT using 99mTc-labeled iminodiacetic acid (IDA) single photon emission computed tomography (SPECT) could predict regional liver function reserve after RT. Methods and Materials: Fourteen patients treated with RT for intrahepatic cancers underwent dynamic 99mTc-IDA SPECT scans before RT, during, and 1 month after completion of RT. Indocyanine green (ICG) tests, a measure of overall liver function, were performed within 1 day of each scan. Three-dimensional volumetric hepatic extraction fraction (HEF) images of the liver were estimated by deconvolution analysis. After coregistration of the CT/SPECT and the treatment planning CT, HEF dose–response functions during and after RT were generated. The volumetric mean of the HEFs in the whole liver was correlated with ICG clearance time. Three models, dose, priori, and adaptive models, were developed using multivariate linear regression to assess whether the regional HEFs measured before and during RT helped predict regional hepatic function after RT. Results: The mean of the volumetric liver HEFs was significantly correlated with ICG clearance half-life time (r=?0.80, P<.0001), for all time points. Linear correlations between local doses and regional HEFs 1 month after RT were significant in 12 patients. In the priori model, regional HEF after RT was predicted by the planned dose and regional HEF assessed before RT (R=0.71, P<.0001). In the adaptive model, regional HEF after RT was predicted by regional HEF reassessed during RT and the remaining planned local dose (R=0.83, P<.0001). Conclusions: 99mTc-IDA SPECT obtained during RT could be used to assess regional hepatic function and helped predict post-RT regional liver function reserve. This could support individualized adaptive radiation treatment strategies to maximize tumor control and minimize the risk of liver damage.
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 ...
Saravanan, Ramalingam [Texas A& M University
2011-10-30T23:59:59.000Z
During the course of this project, we have accomplished the following: a) Carried out studies of climate changes in the past using a hierarchy of intermediate coupled models (Chang et al., 2008; Wan et al 2009; Wen et al., 2010a,b) b) Completed the development of a Coupled Regional Climate Model (CRCM; Patricola et al., 2011a,b) c) Carried out studies testing hypotheses testing the origin of systematic errors in the CRCM (Patricola et al., 2011a,b) d) Carried out studies of the impact of air-sea interaction on hurricanes, in the context of barrier layer interactions (Balaguru et al)
Dynamical coupled-channels model of $K^- p$ reactions (I): Determination of partial-wave amplitudes
H. Kamano; S. X. Nakamura; T. -S. H. Lee; T. Sato
2014-12-12T23:59:59.000Z
We develop a dynamical coupled-channels model of K^- p reactions, aiming at extracting the parameters associated with hyperon resonances and providing the elementary antikaon-nucleon scattering amplitudes that can be used for investigating various phenomena in the strangeness sector such as the production of hypernuclei from kaon-nucleus reactions. The model consists of (a) meson-baryon (MB) potentials v_{M'B',MB} derived from the phenomenological SU(3) Lagrangian, and (b) vertex interactions Gamma_{MB,Y*} for describing the decays of the bare excited hyperon states (Y*) into MB states. The model is defined in a channel space spanned by the two-body barK N, pi Sigma, pi Lambda, eta Lambda, and K Xi states and also the three-body pi pi Lambda and pi barK N states that have the resonant pi Sigma* and barK* N components, respectively. The resulting coupled-channels scattering equations satisfy the multichannel unitarity conditions and account for the dynamical effects arising from the off-shell rescattering processes. The model parameters are determined by fitting the available data of the unpolarized and polarized observables of the K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi reactions in the energy region from the threshold to invariant mass W=2.1 GeV. Two models with equally good chi^2 fits to the data have been constructed. The partial-wave amplitudes obtained from the constructed models are compared with the results from a recent partial-wave analysis by the Kent State University group. We discuss the differences between these three analysis results. Our results at energies near the threshold suggest that the higher partial waves should be treated on the same footing as the S wave if one wants to understand the nature of Lambda(1405)1/2^- using the data below the barK N threshold, as will be provided by the J-PARC E31 experiment.
Modelling the chromosphere and transition region of Epsilon Eri (K2 V)
S. A. Sim; C. Jordan
2005-06-02T23:59:59.000Z
Measurements of ultraviolet line fluxes from Space Telescope Imaging Spectrograph and Far-Ultraviolet Spectroscopic Explorer spectra of the K2-dwarf Epsilon Eri are reported. These are used to develop new emission measure distributions and semi-empirical atmospheric models for the chromosphere and lower transition region of the star. These models are the most detailed constructed to date for a main-sequence star other than the Sun. New ionisation balance calculations, which account for the effect of finite density on dielectronic recombination rates, are presented for carbon, nitrogen, oxygen and silicon. The results of these calculations are significantly different from the standard Arnaud & Rothenflug ion balance, particularly for alkali-like ions. The new atmospheric models are used to place constraints on possible First Ionisation Potential (FIP) related abundance variations in the lower atmosphere and to discuss limitations of single-component models for the interpretation of certain optically thick line fluxes.
Rivington, Michael
2011-06-28T23:59:59.000Z
evidence of how primary production components of agriculture in Scotland may change under a future climate. The work used a generic Integrated Modelling Framework to structure the following sequence of investigations: Evaluate a Regional Climate Model...
Comparing partial-wave amplitude parametrization with dynamical models of meson-nucleon scattering
Mark W. Paris; Ron L. Workman
2011-02-28T23:59:59.000Z
Relationships between partial-wave amplitude parametrizations, in particular the Chew-Mandelstam approach, and dynamical coupled-channel models are established and investigated. A bare pole corresponding to the Delta(1232) resonance, found in a recent dynamical-model fit to pion- and omega-meson production reactions, compares closely to one found in a unitary multichannel partial-wave amplitude parametrization of SAID. The model dependence of the bare pole precludes a direct connection between the approaches but is suggestive that the dynamical description and the phenomenological parametrization are closely related.
AN APPLICATION OF URBANSIM TO THE AUSTIN, TEXAS REGION: INTEGRATED-MODEL FORECASTS FOR THE YEAR 2030
Kockelman, Kara M.
AN APPLICATION OF URBANSIM TO THE AUSTIN, TEXAS REGION: INTEGRATED-MODEL FORECASTS FOR THE YEAR, as well as energy consumption and greenhouse gas emissions. This work describes the modeling of year-2030 policies significantly impact the region's future land use patterns, traffic conditions, greenhouse gas
Stacey, W.M.
1992-12-01T23:59:59.000Z
A new computational model for neutral particle transport in the outer regions of a diverted tokamak plasma chamber is presented. The model is based on the calculation of transmission and escape probabilities using first-flight integral transport theory and the balancing of fluxes across the surfaces bounding the various regions. The geometrical complexity of the problem is included in precomputed probabilities which depend only on the mean free path of the region.
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 ...
SIMULATING MARKET TRANSFORMATION DYNAMICS USING A HYBRID ENERGY ECONOMY MODEL
AT THE ADOPTION OF HYDROGEN FUEL CELL VEHICLES by Jimena Eyzaguirre M.Sc. Geology, University of Western Ontario, to develop policy-relevant information about dynamics in consumer preferences for hydrogen fuel cell vehicles
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 ...
Isomorphic classical molecular dynamics model for an excess electronin a supercritical fluid
Miller III, Thomas F.
2008-08-04T23:59:59.000Z
Ring polymer molecular dynamics (RPMD) is used to directly simulate the dynamics of an excess electron in a supercritical fluid over a broad range of densities. The accuracy of the RPMD model is tested against numerically exact path integral statistics through the use of analytical continuation techniques. At low fluid densities, the RPMD model substantially underestimates the contribution of delocalized states to the dynamics of the excess electron. However, with increasing solvent density, the RPMD model improves, nearly satisfying analytical continuation constraints at densities approaching those of typical liquids. In the high density regime, quantum dispersion substantially decreases the self-diffusion of the solvated electron. In this regime where the dynamics of the electron is strongly coupled to the dynamics of the atoms in the fluid, trajectories that can reveal diffusive motion of the electron are long in comparison to {beta}{h_bar}.
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...
Brownian Dynamics Model of Excited-State Relaxation in Solutions of Conjugated Oligomers
Yaron, David
1 Brownian Dynamics Model of Excited-State Relaxation in Solutions of Conjugated Oligomers Nicolae, Pittsburgh, Pennsylvania 15213. Excited state relaxation, conjugated polymers, Brownian dynamics. The effects, of the oligomer. A simple molecular mechanical form is used for the ground electronic state. The excitation energy
LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model
LIDAR measurements of wind turbine wake dyn_amics and comparison with an engineering model 1 dynamics, lIre performed at four diameters behind a 95 kW wind turbine. The wake 111eaeasurement technique allows esti111ation of qUClsiinstantancou~ two dimensional wind fields in an area
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.B. Gu and C.Y. Wang GATE Center of Excellence for Advanced Energy Storage Department of Mechanical are performed using a finite volume method of computational fluid dynamics. The predicted discharge curves
StankoviÃ¦, Aleksandar
Dynamic Phasor Modeling of the Doubly-Fed Induction Machine in Generator Operation Emmanuel at variable speed; second, the excitation power electronics converter feeding the rotor windings needs of the doubly- fed induction machine in generator operation using dynamic phasors. This concept is coming from
Gurson's plasticity coupled to damage as a CAP model for concrete compaction in dynamics
1 Gurson's plasticity coupled to damage as a CAP model for concrete compaction in dynamics Fabrice (compaction) but also the plastic strains in compression and cracking in tension. Recently, new dynamic is generally described by means of the plasticity theory where the spherical and the deviatoric responses
Van den Hof, Paul
on dynamic real-time optimization (D- RTO) of waterflooding strategies in petroleum reservoirs haveIntegrated Dynamic Optimization and Control in Reservoir Engineering using Locally Identified, the used large-scale, nonlinear, physics-based reservoir models suffer from vast parametric uncertainty
Pedram, Massoud
An Energy-Aware Simulation Model and Transaction Protocol for Dynamic Workload Distribution California {tari, prong, pedram}@usc.edu Abstract This paper introduces a network simulation model
RÃ¶der, Beate
complemented by various experiments focusing on the dynamics of excitation energy transfer and relaxation afterFrom Structure to Dynamics: Modeling Exciton Dynamics in the Photosynthetic Antenna PS1 B. Bru1 of Sciences and Institute of Molecular Biological Sciences, Vrije UniVersiteit, De Boelelaan 1081, 1081 HV
A two-dimensional regional basin model of Williston basin hydrocarbon systems
Burrus, J.; Wolf, S.; Doligez, B. [Institut Francais due Petrole, Rueil-Malmaison (France)] [and others
1996-02-01T23:59:59.000Z
Institut Francais du Petrole`s two-dimensional model, TEMISPACK, is used to discuss the functioning of petroleum systems in the Williston basin along a 330-km-long section, focusing on four regional source intervals: Ordovician Yeoman formation, Lower Devonian Winnipegosis Formation, Upper Devonian-Lower Mississippian Bakken Formation, and Mississippian Lodgepole formation. Thermal history calibration against present temperature and source rock maturity profiles suggests that the Williston basin can be divided into a region of constant heat flow of about 55 mW/m{sup 2} away from the Nesson anticline, and a region of higher heat flow and enhanced thermal maturity in the vicinity of the Nesson anticline. Original kinetic parameters used in the calibration were derived for each of the four source rocks from Rock-Eval yield curves. Bakken overpressures are entirely due to oil generation, not compaction disequilibrium. Very low Bakken vertical permeabilities range from 0.01 to 0.001 and are matched against observed overpressures, whereas Bakken porosities based on the model and confirmed by measurements are inferred to be also unusually low, around 3%.
Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites
Gaddamanugu, Dhatri
2010-07-14T23:59:59.000Z
Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading...
Optimal motion planning with the half-car dynamical model for autonomous high-speed driving
Jeon, Jeong hwan
We discuss an implementation of the RRT* optimal motion planning algorithm for the half-car dynamical model to enable autonomous high-speed driving. To develop fast solutions of the associated local steering problem, we ...
Wei, Zheng, S.M. Massachusetts Institute of Technology
2010-01-01T23:59:59.000Z
To accurately replicate the highly congested traffic situation of a complex urban network, significant challenges are posed to current simulation-based dynamic traffic assignment (DTA) models. This thesis discusses these ...
Branching patterns emerge in a mathematical model of the dynamics of lung development
2014-01-01T23:59:59.000Z
fluid pressure and fluid–mechanical interactions. Lubarsky &The absence of fluid or mechanical effects may also ex-model to the mechanical and fluid dynamical factors in lung
The Effect of Model Parameters on the Simulation of Fire Dynamics
Jahn, Wolfram; Rein, Guillermo; Torero, Jose L
2008-01-01T23:59:59.000Z
The sensitivity of computer fire modelling using results from NIST’s Fire Dynamics Simulator (FDS) to a set of input parameters related to fire growth has been analyzed. The scenario simulated is the real-scale Dalmarnock ...
Coupled Modeling of Dynamic Reservoir/Well Interactions under Liquid-loading Conditions
Limpasurat, Akkharachai
2013-10-23T23:59:59.000Z
backpressure on the formation, which decreases the gas production rate and may stop the well from flowing. To model these phenomena, the dynamic interaction between the reservoir and the wellbore must be characterized. Due to wellbore phase re...
A Mechanical Fluid-Dynamical Model For Ground Movements At Campi...
Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Mechanical...
Sheng, Hongyan
1999-01-01T23:59:59.000Z
market share for alternative-fuel vehicles drop from thePreferences for Alternative-Fuel Vehicles”, Brownstone DavidA Dynamic Household Alternative-fuel Vehicle Demand Model
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 ...
Building Dynamic Models of Service Compositions with Simulation of Provision Resources
Dustdar, Schahram
Building Dynamic Models of Service Compositions with Simulation of Provision Resources Dragan compositions depends both on the composition structure, and on planning and management of compu- tational resources necessary for provision. Resource constraints on the service provider side have impact
Lucarini, V; Kriegerova, I; Speranza, A; Danihlik, Robert; Kriegerova, Ida; Lucarini, Valerio; Speranza, Antonio
2006-01-01T23:59:59.000Z
We present an intercomparison and verification analysis of several regional climate models (RCMs) nested into the same run of the same Atmospheric Global Circulation Model (AGCM) regarding their representation of the statistical properties of the hydrological balance of the Danube river basin for 1961-1990. We also consider the datasets produced by the driving AGCM, from the ECMWF and NCEP-NCAR reanalyses. The hydrological balance is computed by integrating the precipitation and evaporation fields over the area of interest. Large discrepancies exist among RCMs for the monthly climatology as well as for the mean and variability of the annual balances, and only few datasets are consistent with the observed discharge values of the Danube at its Delta, even if the driving AGCM provides itself an excellent estimate. Since the considered approach relies on the mass conservation principle and bypasses the details of the air-land interface modeling, we propose that the atmospheric components of RCMs still face diffic...
Learning Dynamic Models of Compartment Systems by Combining Symbolic Regression with Fuzzy Vector
Fernandez, Thomas
. Categories and Subject Descriptors I.2.1 [Pattern Recognition]: Models--Fuzzy Set; I.2.6 [ArtificialLearning Dynamic Models of Compartment Systems by Combining Symbolic Regression with Fuzzy Vector and fuzzy represen- tation. We need differential capabilities because, in a dy- namic environment, models
From "Stages" of Business Growth to a Dynamic States Model of Entrepreneurial Growth and Change
Mottram, Nigel
From "Stages" of Business Growth to a Dynamic States Model of Entrepreneurial Growth and Change and Gumpert, 1985), and virtually all economic models of business creation follow firm birth with firm growth models of new business growth assume a limited number of distinct stages through #12;3 which businesses
O'Brien, Travis A.; Li, Fuyu; Collins, William D.; Rauscher, Sara; Ringler, Todd; Taylor, Mark; Hagos, Samson M.; Leung, Lai-Yung R.
2013-12-01T23:59:59.000Z
We use observations of robust scaling behavior in clouds and precipitation to derive constraints on how partitioning of precipitation should change with model resolution. Our analysis indicates that 90-99% of stratiform precipitation should occur in clouds that are resolvable by contemporary climate models (e.g., with 200 km or finer grid spacing). Furthermore, this resolved fraction of stratiform precipitation should increase sharply with resolution, such that effectively all stratiform precipitation should be resolvable above scales of ~50 km. We show that the Community Atmosphere Model (CAM) and the Weather Research and Forecasting (WRF) model also exhibit the robust cloud and precipitation scaling behavior that is present in observations, yet the resolved fraction of stratiform precipitation actually decreases with increasing model resolution. A suite of experiments with multiple dynamical cores provides strong evidence that this `scale-incognizant' behavior originates in one of the CAM4 parameterizations. An additional set of sensitivity experiments rules out both convection parameterizations, and by a process of elimination these results implicate the stratiform cloud and precipitation parameterization. Tests with the CAM5 physics package show improvements in the resolution-dependence of resolved cloud fraction and resolved stratiform precipitation fraction.
Dynamics of the Oil Transition: Modeling Capacity, Costs, and Emissions
Brandt, Adam R.; Farrell, Alexander E.
2008-01-01T23:59:59.000Z
market, allowing our model to focus on the supply of crude oil andterms of the model equations [7]). The oil market in ROMEO
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.
Quantification of model mismatch errors of the dynamic energy distribution in a stirred-tank reactor
Kimmich, Mark Raymond
1987-01-01T23:59:59.000Z
QUANTIFICATION OF MODEL MISMATCH ERRORS OF THE DYNAMIC ENERGY DISTRIBUTION IN A STIRRED- TANK REACTOR A Thesis by MARK RAYMOND KIMMICH Submitted to the Graduate College of Texas AkM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 198i Major Subject: Chemical Engineering QUANTIFICATION OF MODEL MISMATCH ERRORS OF THE DYNAMIC ENERGY DISTRIBUTION IN A STIRRED-TANK REACTOR A Thesis by MARK RAYMOND KIMMICH Approved as to style and content by...
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.
Spatial Variation of Soil Type and Soil Moisture in the Regional Atmospheric Modeling System
Buckley, R.
2001-06-27T23:59:59.000Z
Soil characteristics (texture and moisture) are typically assumed to be initially constant when performing simulations with the Regional Atmospheric Modeling System (RAMS). Soil texture is spatially homogeneous and time-independent, while soil moisture is often spatially homogeneous initially, but time-dependent. This report discusses the conversion of a global data set of Food and Agriculture Organization (FAO) soil types to RAMS soil texture and the subsequent modifications required in RAMS to ingest this information. Spatial variations in initial soil moisture obtained from the National Center for Environmental Predictions (NCEP) large-scale models are also introduced. Comparisons involving simulations over the southeastern United States for two different time periods, one during warmer, more humid summer conditions, and one during cooler, dryer winter conditions, reveals differences in surface conditions related to increases or decreases in near-surface atmospheric moisture con tent as a result of different soil properties. Three separate simulation types were considered. The base case assumed spatially homogeneous soil texture and initial soil moisture. The second case assumed variable soil texture and constant initial soil moisture, while the third case allowed for both variable soil texture and initial soil moisture. The simulation domain was further divided into four geographically distinct regions. It is concluded there is a more dramatic impact on thermodynamic variables (surface temperature and dewpoint) than on surface winds, and a more pronounced variability in results during the summer period. While no obvious trends in surface winds or dewpoint temperature were found relative to observations covering all regions and times, improvement in surface temperatures in most regions and time periods was generally seen with the incorporation of variable soil texture and initial soil moisture.
Impact of Agricultural Practice on Regional Climate in a CoupledLand Surface Mesoscale Model
Cooley, H.S.; Riley, W.J.; Torn, M.S.; He, Y.
2004-07-01T23:59:59.000Z
The land surface has been shown to form strong feedbacks with climate due to linkages between atmospheric conditions and terrestrial ecosystem exchanges of energy, momentum, water, and trace gases. Although often ignored in modeling studies, land management itself may form significant feedbacks. Because crops are harvested earlier under drier conditions, regional air temperature, precipitation, and soil moisture, for example, affect harvest timing, particularly of rain-fed crops. This removal of vegetation alters the land surface characteristics and may, in turn, affect regional climate. We applied a coupled climate(MM5) and land-surface (LSM1) model to examine the effects of early and late winter wheat harvest on regional climate in the Department of Energy Atmospheric Radiation Measurement (ARM) Climate Research Facility in the Southern Great Plains, where winter wheat accounts for 20 percent of the land area. Within the winter wheat region, simulated 2 m air temperature was 1.3 C warmer in the Early Harvest scenario at mid-day averaged over the two weeks following harvest. Soils in the harvested area were drier and warmer in the top 10 cm and wetter in the 10-20 cm layer. Midday soils were 2.5 C warmer in the harvested area at mid-day averaged over the two weeks following harvest. Harvest also dramatically altered latent and sensible heat fluxes. Although differences between scenarios diminished once both scenarios were harvested, the short-term impacts of land management on climate were comparable to those from land cover change demonstrated in other studies.
An anticipatory integrated assessment of regional acidification: The RAINS-Asia model
Amann, M. [International Institute for Applied Systems Analysis, Laxenburg (Austria); Carmichael, G.R. [Univ. of Iowa, Iowa City, IA (United States); Foell, W. [Resource Management Associates, Madison, WI (United States)] [and others
1996-12-31T23:59:59.000Z
Across large parts of Asia, air pollution problems are becoming more and more evident. Rainfall in some areas, including China, Japan, and Thailand, has been measured to be 10 times more acidic than unpolluted rain. Increasing evidence of acidification damage to ecosystems such as surface waters, soils, and economically important crops, is beginning to appear. In addition, urban air quality in many areas of the region continues to decrease. Current economic forecasts predict continued rapid economic growth in the region, which will bring with it increasing emissions of air pollutants, especially sulfur. The total primary energy demand in Asia currently doubles every twelve years (as compared to a world average of every 28 years). Coal is expected to continue to be the dominant energy source, with coal demand projected to increase by 65 percent per year, a rate that outpaces regional economic growth. If current trends in economic development and energy use in Asia continue, emissions of sulfur dioxide, one of the key components in acid rain, will more than triple within the next 30 years. Many ecosystems will be unable to continue to absorb these increased levels of pollution without harmful effects, thus creating a potential danger for irreversible environmental damage in many areas. In view of the potential environmental consequences of projected growth in Asian energy consumption, emissions, and air pollution, the World Bank, together with the Asian Development Bank, have funded a project to develop and implement an integrated assessment model for the acid deposition phenomenon in Asia. The Regional Air Pollution INformation and Simulation model for Asia (RAINS-Asia) is a software tool to help decision makers assess and project future trends in emissions, transport, and deposition of air pollutants, and their potential environmental effects.
Dynamic Models for Spatio-Temporal Data By JONATHAN STROUD
West, Mike
examples include monitoring of regional ozone levels, disease mapping, and analysis of global warming: tropical rainfall levels and Atlantic ocean temperatures. Keywords: BAYESIAN INFERENCE; LOCALLY with kriging and long-memory dependence to study global w
A Competitive and Dynamic Pricing Model for Secondary Users in Infrastructure based Networks
Yanikomeroglu, Halim
to the Wireless Service Providers (WSPs) for achieving efficient radio spectrum usage as well as gain additional dynamically with the changing radio spectrum usage at the BS. Assuming high competition among regional WSPs (WSPs) in acquiring the licensed spectrum, have a serious impact on the bottom line of the WSPs
Photodissociation dynamics of C{sub 3}H{sub 5}I in the near-ultraviolet region
Sumida, Masataka; Hanada, Takuya; Yamasaki, Katsuyoshi; Kohguchi, Hiroshi, E-mail: kohguchi@hiroshima-u.ac.jp [Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
2014-09-14T23:59:59.000Z
The ultraviolet photodissociation dynamics of allyl iodide (C{sub 3}H{sub 5}I) have been studied by ion-imaging at 266 nm and 213 nm. These photolysis wavelengths are located in the two lowest absorption bands in the near-ultraviolet region. The atomic iodine products were detected by [2+1] resonantly enhanced multiphoton ionization spectroscopy. The spectra showed that the branching fraction for the spin-orbit excited ({sup 2}P{sub 1/2}) state was larger than that for the ground ({sup 2}P{sub 3/2}) state at both photolysis wavelengths. The state-resolved scattering images of iodine showed two maxima in the velocity distributions in the {sup 2}P{sub 3/2} state and a single peak in the {sup 2}P{sub 1/2} state. The spin-orbit specificity indicates that the C?I bond cleavage at both absorption bands is governed by the dissociative n{sub I}?{sup *}{sub C?I} potential energy surfaces. The nascent internal energy distribution of the allyl radical (C{sub 3}H{sub 5}) counter product, which was obtained by the analysis of the state-resolved scattering distributions, showed a marked difference between the photolysis at 266 nm and 213 nm. The generation of the colder C{sub 3}H{sub 5} with the higher translational energy at 266 nm implied the direct photoexcitation to the n{sub I}?{sup *}{sub C?I} repulsive surfaces, whereas the internally hot C{sub 3}H{sub 5} at 213 nm was ascribed to the local ?{sub CC}?{sup *}{sub CC} photoinitiation in the allyl framework followed by predissociation to the n{sub I}?{sup *}{sub C?I} states.
Prof. Alessandro De Luca Dynamic model of robots
De Luca, Alessandro
, identification, uses #12;Analysis of inertial couplings ! Cartesian robot ! Cartesian "skew" robot ! PR robot ! 2 advantage for the design of a motion control law! (*) structural condition in mechanical design Robotics 2 8 in the mechanical design lead to g(q) 0!! Robotics 2 9 #12;Adding dynamic terms ... ! dissipative phenomena due
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.
Bair, Wyeth
74 Chapter 6 Modeling Spike Trains from Area MT This chapter describes the application of a motion energy model to the dynamic dot stimulus. We wanted to know whether the precise temporal modulation widely compared to electrophysiological data from both area MT and its V1 inputs (Heeger, 1987; Grzywacz
Regional groundwater flow model for C, K. L. and P reactor areas, Savannah River Site, Aiken, SC
Flach, G.P.
2000-02-11T23:59:59.000Z
A regional groundwater flow model encompassing approximately 100 mi2 surrounding the C, K, L, and P reactor areas has been developed. The reactor flow model is designed to meet the planning objectives outlined in the General Groundwater Strategy for Reactor Area Projects by providing a common framework for analyzing groundwater flow, contaminant migration and remedial alternatives within the Reactor Projects team of the Environmental Restoration Department. The model provides a quantitative understanding of groundwater flow on a regional scale within the near surface aquifers and deeper semi-confined to confined aquifers. The model incorporates historical and current field characterization data up through Spring 1999. Model preprocessing is automated so that future updates and modifications can be performed quickly and efficiently. The CKLP regional reactor model can be used to guide characterization, perform scoping analyses of contaminant transport, and serve as a common base for subsequent finer-scale transport and remedial/feasibility models for each reactor area.
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.
Zhang, Xuesong; Izaurralde, Roberto C.; Manowitz, David H.; Sahajpal, Ritvik; West, Tristram O.; Thomson, Allison M.; Xu, Min; Zhao, Kaiguang; LeDuc, Stephen D.; Williams, Jimmy R.
2015-01-01T23:59:59.000Z
Accurate quantification and clear understanding of regional scale cropland carbon (C) cycling is critical for designing effective policies and management practices that can contribute toward stabilizing atmospheric CO2 concentrations. However, extrapolating site-scale observations to regional scales represents a major challenge confronting the agricultural modeling community. This study introduces a novel geospatial agricultural modeling system (GAMS) exploring the integration of the mechanistic Environmental Policy Integrated Climate model, spatially-resolved data, surveyed management data, and supercomputing functions for cropland C budgets estimates. This modeling system creates spatially-explicit modeling units at a spatial resolution consistent with remotely-sensed crop identification and assigns cropping systems to each of them by geo-referencing surveyed crop management information at the county or state level. A parallel computing algorithm was also developed to facilitate the computationally intensive model runs and output post-processing and visualization. We evaluated GAMS against National Agricultural Statistics Service (NASS) reported crop yields and inventory estimated county-scale cropland C budgets averaged over 2000–2008. We observed good overall agreement, with spatial correlation of 0.89, 0.90, 0.41, and 0.87, for crop yields, Net Primary Production (NPP), Soil Organic C (SOC) change, and Net Ecosystem Exchange (NEE), respectively. However, we also detected notable differences in the magnitude of NPP and NEE, as well as in the spatial pattern of SOC change. By performing crop-specific annual comparisons, we discuss possible explanations for the discrepancies between GAMS and the inventory method, such as data requirements, representation of agroecosystem processes, completeness and accuracy of crop management data, and accuracy of crop area representation. Based on these analyses, we further discuss strategies to improve GAMS by updating input data and by designing more efficient parallel computing capability to quantitatively assess errors associated with the simulation of C budget components. The modularized design of the GAMS makes it flexible to be updated and adapted for different agricultural models so long as they require similar input data, and to be linked with socio-economic models to understand the effectiveness and implications of diverse C management practices and policies.
The sine-Gordon model and the small. kappa. sup + region of light- cone perturbation theory
Griffin, P.A.
1992-01-01T23:59:59.000Z
The non-perturbative ultraviolet divergence of the sine-Gordon model is used to study the k{sup +} = 0 region of light-cone perturbation theory. The light-cone vacuum is shown to be unstable at the non- perturbative {beta}{sup 2} = 8{pi} critical point by a light-cone version of Coleman's variational method. Vacuum bubbles, which are k{sup +} = 0 diagram in light-cone field theory and are individually finite and non-vanishing for all {beta}, conspire to generate ultraviolet divergences of the light-cone energy density. The k{sup +} = 0 region of momentum also contributed to connected Green's functions: the connected two point function will not diverge, as it should, at the critical point unless diagrams which contribute only at k {sup +} = 0 are properly included. This analysis shows in a simple way how the k {sup +} = 0 region cannot be ignored even for connected diagrams. This phenomenon is expected to occur in higher dimensional gauge theories starting at two loop order in light-cone perturbation theory.
Generalized CP symmetries and special regions of parameter space in the two-Higgs-doublet model
Ferreira, P. M. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California 95064 (United States); Silva, Joao P. [Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emidio Navarro, 1900 Lisboa (Portugal); Centro de Fisica Teorica de Particulas, Instituto Superior Tecnico, P-1049-001 Lisboa (Portugal)
2009-06-01T23:59:59.000Z
We consider the impact of imposing generalized CP symmetries on the Higgs sector of the two-Higgs-doublet model, and identify three classes of symmetries. Two of these classes constrain the scalar potential parameters to an exceptional region of parameter space, which respects either a Z{sub 2} discrete flavor symmetry or a U(1) symmetry. We exhibit a basis-invariant quantity that distinguishes between these two possible symmetries. We also show that the consequences of imposing these two classes of CP symmetry can be achieved by combining Higgs family symmetries, and that this is not possible for the usual CP symmetry. We comment on the vacuum structure and on renormalization in the presence of these symmetries. Finally, we demonstrate that the standard CP symmetry can be used to build all the models we identify, including those based on Higgs family symmetries.
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.
Kota, Sri H
2014-07-25T23:59:59.000Z
and inventories of CO, NO_(x) and VOCs from on-road vehicles estimated by vehicle emission factor models and biogenic emissions of isoprene estimated by a popular biogenic emission model are evaluated using local and regional scale air quality modeling and source...
Walton, W.C.; Voorhees, M.L.; Prickett, T.A.
1980-05-23T23:59:59.000Z
This technical memorandum was prepared to: (1) describe a typical basalt radionuclide repository site, (2) describe geologic and hydrologic processes associated with regional radionuclide transport in basalts, (3) define the parameters required to model regional radionuclide transport from a basalt repository site, and (4) develop a ''conceptual model'' of radionuclide transport from a basalt repository site. In a general hydrological sense, basalts may be described as layered sequences of aquifers and aquitards. The Columbia River Basalt, centered near the semi-arid Pasco Basin, is considered by many to be typical basalt repository host rock. Detailed description of the flow system including flow velocities with high-low hydraulic conductivity sequences are not possible with existing data. However, according to theory, waste-transport routes are ultimately towards the Columbia River and the lengths of flow paths from the repository to the biosphere may be relatively short. There are many physical, chemical, thermal, and nuclear processes with associated parameters that together determine the possible pattern of radionuclide migration in basalts and surrounding formations. Brief process descriptions and associated parameter lists are provided. Emphasis has been placed on the use of the distribution coefficient in simulating ion exchange. The use of the distribution coefficient approach is limited because it takes into account only relatively fast mass transfer processes. In general, knowledge of hydrogeochemical processes is primitive.
A One-Dimensional (1-D) Three-Region Model for a Bubbling Fluidized-Bed Adsorber
Lee, Andrew; Miller, David C.
2012-01-01T23:59:59.000Z
A general one-dimensional (1-D), three-region model for a bubbling fluidized-bed adsorber with internal heat exchangers has been developed. The model can predict the hydrodynamics of the bed and provides axial profiles for all temperatures, concentrations, and velocities. The model is computationally fast and flexible and allows for any system of adsorption and desorption reactions to be modeled, making the model applicable to any adsorption process. The model has been implemented in both gPROMS and Aspen Custom Modeler, and the behavior of the model has been verified.
ModelingAtmosphericChemistryand Transport with Dynamic Adaptive Resolution
Sandu, Adrian
pollution has important implications for urban and regional air quality, for human health, and for climate avenues. Advantages and shortcomings of the present approach are also discussed. Keywords: air pollution be an important source of errors in CTMs. In air pollution simulations large spatial gradients of tracer
Lehikoinen, A.; Huttunen, J.M.J.; Finsterle, S.; Kowalsky, M.B.; Kaipio, J.P.
2009-08-01T23:59:59.000Z
We propose an approach for imaging the dynamics of complex hydrological processes. The evolution of electrically conductive fluids in porous media is imaged using time-lapse electrical resistance tomography. The related dynamic inversion problem is solved using Bayesian filtering techniques, that is, it is formulated as a sequential state estimation problem in which the target is an evolving posterior probability density of the system state. The dynamical inversion framework is based on the state space representation of the system, which involves the construction of a stochastic evolution model and an observation model. The observation model used in this paper consists of the complete electrode model for ERT, with Archie's law relating saturations to electrical conductivity. The evolution model is an approximate model for simulating flow through partially saturated porous media. Unavoidable modeling and approximation errors in both the observation and evolution models are considered by computing approximate statistics for these errors. These models are then included in the construction of the posterior probability density of the estimated system state. This approximation error method allows the use of approximate - and therefore computationally efficient - observation and evolution models in the Bayesian filtering. We consider a synthetic example and show that the incorporation of an explicit model for the model uncertainties in the state space representation can yield better estimates than a frame-by-frame imaging approach.
Voisin, Nathalie; Li, Hongyi; Ward, Duane L.; Huang, Maoyi; Wigmosta, Mark S.; Leung, Lai-Yung R.
2013-09-30T23:59:59.000Z
Human influence on the hydrologic cycle includes regulation and storage, consumptive use and overall redistribution of water resources in space and time. Representing these processes is essential for applications of earth system models in hydrologic and climate predictions, as well as impact studies at regional to global scales. Emerging large-scale research reservoir models use generic operating rules that are flexible for coupling with earth system models. Those generic operating rules have been successful in reproducing the overall regulated flow at large basin scales. This study investigates the uncertainties of the reservoir models from different implementations of the generic operating rules using the complex multi-objective Columbia River Regulation System in northwestern United States as an example to understand their effects on not only regulated flow but also reservoir storage and fraction of the demand that is met. Numerical experiments are designed to test new generic operating rules that combine storage and releases targets for multi-purpose reservoirs and to compare the use of reservoir usage priorities, withdrawals vs. consumptive demand, as well as natural vs. regulated mean flow for calibrating operating rules. Overall the best performing implementation is the use of the combined priorities (flood control storage targets and irrigation release targets) operating rules calibrated with mean annual natural flow and mean monthly withdrawals. The challenge of not accounting for groundwater withdrawals, or on the contrary, assuming that all remaining demand is met through groundwater extractions, is discussed.
Dynamic cone beam CT angiography of carotid and cerebral arteries using canine model
Cai Weixing; Zhao Binghui; Conover, David; Liu Jiangkun; Ning Ruola [Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Radiology, Shanghai 6th People's Hospital, 600 Yishan Road, Xuhui, Shanghai (China); Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States); Department of Imaging Sciences, University of Rochester, 601 Elmwood Avenue, Rochester, New York 14642 (United States) and Koning Corporation, Lennox Tech Enterprise Center, 150 Lucius Gordon Drive Suite 112, West Henrietta, New York 14586 (United States)
2012-01-15T23:59:59.000Z
Purpose: This research is designed to develop and evaluate a flat-panel detector-based dynamic cone beam CT system for dynamic angiography imaging, which is able to provide both dynamic functional information and dynamic anatomic information from one multirevolution cone beam CT scan. Methods: A dynamic cone beam CT scan acquired projections over four revolutions within a time window of 40 s after contrast agent injection through a femoral vein to cover the entire wash-in and wash-out phases. A dynamic cone beam CT reconstruction algorithm was utilized and a novel recovery method was developed to correct the time-enhancement curve of contrast flow. From the same data set, both projection-based subtraction and reconstruction-based subtraction approaches were utilized and compared to remove the background tissues and visualize the 3D vascular structure to provide the dynamic anatomic information. Results: Through computer simulations, the new recovery algorithm for dynamic time-enhancement curves was optimized and showed excellent accuracy to recover the actual contrast flow. Canine model experiments also indicated that the recovered time-enhancement curves from dynamic cone beam CT imaging agreed well with that of an IV-digital subtraction angiography (DSA) study. The dynamic vascular structures reconstructed using both projection-based subtraction and reconstruction-based subtraction were almost identical as the differences between them were comparable to the background noise level. At the enhancement peak, all the major carotid and cerebral arteries and the Circle of Willis could be clearly observed. Conclusions: The proposed dynamic cone beam CT approach can accurately recover the actual contrast flow, and dynamic anatomic imaging can be obtained with high isotropic 3D resolution. This approach is promising for diagnosis and treatment planning of vascular diseases and strokes.
Subin, Z.M.; Riley, W.J.; Kueppers, L.M.; Jin, J.; Christianson, D.S.; Torn, M.S.
2010-11-01T23:59:59.000Z
A regional atmosphere model [Weather Research and Forecasting model version 3 (WRF3)] and a land surface model [Community Land Model, version 3.5 (CLM3.5)] were coupled to study the interactions between the atmosphere and possible future California land-cover changes. The impact was evaluated on California's climate of changes in natural vegetation under climate change and of intentional afforestation. The ability of WRF3 to simulate California's climate was assessed by comparing simulations by WRF3-CLM3.5 and WRF3-Noah to observations from 1982 to 1991. Using WRF3-CLM3.5, the authors performed six 13-yr experiments using historical and future large-scale climate boundary conditions from the Geophysical Fluid Dynamics Laboratory Climate Model version 2.1 (GFDL CM2.1). The land-cover scenarios included historical and future natural vegetation from the Mapped Atmosphere-Plant-Soil System-Century 1 (MC1) dynamic vegetation model, in addition to a future 8-million-ha California afforestation scenario. Natural vegetation changes alone caused summer daily-mean 2-m air temperature changes of -0.7 to +1 C in regions without persistent snow cover, depending on the location and the type of vegetation change. Vegetation temperature changes were much larger than the 2-m air temperature changes because of the finescale spatial heterogeneity of the imposed vegetation change. Up to 30% of the magnitude of the summer daily-mean 2-m air temperature increase and 70% of the magnitude of the 1600 local time (LT) vegetation temperature increase projected under future climate change were attributable to the climate-driven shift in land cover. The authors projected that afforestation could cause local 0.2-1.2 C reductions in summer daily-mean 2-m air temperature and 2.0-3.7 C reductions in 1600 LT vegetation temperature for snow-free regions, primarily because of increased evapotranspiration. Because some of these temperature changes are of comparable magnitude to those projected under climate change this century, projections of climate and vegetation change in this region need to consider these climate-vegetation interactions.
Pricing Bivariate Option under GARCH-GH Model with Dynamic Copula: Application for
Paris-Sud XI, Université de
Pricing Bivariate Option under GARCH-GH Model with Dynamic Copula: Application for Chinese Market D Heteroskedastic (GARCH) process. In order to provide a general framework being able to accommodate skewness by the GARCH-GH model with time-varying copula differ substantially from the prices implied by the GARCH
Modelling propagation of sinkhole, in both slow and dynamic modes, using the UDEC computer code.
Paris-Sud XI, UniversitÃ© de
Modelling propagation of sinkhole, in both slow and dynamic modes, using the UDEC computer code RISques) : Adresse* : Ecole des mines de Nancy, Parc de Saurupt, 54042 Nancy-Cedex, France ; Adresse sinkhole forms and to propose a prediction model. The UDEC code is used. An actual case of sinkhole
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.
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
A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu
A Dynamic Supply-Demand Model for Electricity Prices Manuela Buzoianu , Anthony E. Brockwell, and Duane J. Seppi Abstract We introduce a new model for electricity prices, based on the principle in a study of Californian wholesale electricity prices over a three-year period including the crisis period
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.
Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics and Kinematics
Grilli, StÃ©phan T.
Numerical Modeling of Nonlinear Surface Waves caused by Surface Effect Ships Dynamics and Kinematics Hong Gun SungÂ½ and Stephan T. GrilliÂ¾ Â½ Korea Ocean Research and Development Institute, Daejeon model fully nonlinear free surface waves caused by a translating dis- turbance made of a pressure patch
Dynamic Modeling by Usage Data for Personalization Systems Saeed R. Aghabozorgi1
Hammerton, James
Dynamic Modeling by Usage Data for Personalization Systems Saeed R. Aghabozorgi1 , Teh Ying Wah2 Department of Information Science, Faculty of Computer Science and Information Technology, University mining algorithms to personalize web sites' usage data. This paper proposes an off-line model based web
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-three-dimensional suspended sediment transport model was developed and generalized to include combined wave-current effects to study bottom sediment resuspension and transport in southern Lake Michigan. The results from a three
Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu
Gray, Wayne
Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu Human Factors in several ways. Modeling the impact of one such difference raised theoretical issues in motor movement and attention. For motor movement, the issue concerned the functional shape and size of a target
A climate model intercomparison at the dynamics level Karsten Steinhaeuser Anastasios A. Tsonis
Minnesota, University of
A climate model intercomparison at the dynamics level Karsten Steinhaeuser Â· Anastasios A. Tsonis-Verlag Berlin Heidelberg 2013 Abstract Until now, climate model intercomparison has focused primarily on annual they generate, we have adopted a new approach based on climate networks. We have considered 28 pre
A climate model intercomparison at the dynamics level Karsten Steinhaeuser Anastasios A. Tsonis
Minnesota, University of
A climate model intercomparison at the dynamics level Karsten Steinhaeuser Â· Anastasios A. Tsonis Until now, climate model intercomparison has focused primarily on annual and global averages of various adopted a new approach based on climate networks. We have considered 28 pre-industrial control runs
A Fiber Tracking Method for Building Patient Specific Dynamic Musculoskeletal Models from
Gilles, Benjamin
A Fiber Tracking Method for Building Patient Specific Dynamic Musculoskeletal Models from Diffusion tracking algorithm based on an energy minimizing active curve that is well suited for building these strand and FEM models are complex to construct and time intensive to simulate. Recently a new simulation
Modeling of quasistatic and dynamic load responses of filled viscoelastic materials
are typically used for static finite element analysis (see [9]). The CRSC/Lord team worked, both theoreticallyModeling of quasiÂstatic and dynamic load responses of filled viscoelastic materials H.T. Banks factors to the complications arising in the process of formulating models. Damping is highly complex
Simulation of aerosol dynamics: a comparative review of mathematical models
Seigneur, C.; Hudischewskyj, A.B.; Seinfeld, J.H.; Whitby, K.T.; Whitby, E.R.
1986-01-01T23:59:59.000Z
Three modeling approaches used are based-continuous, discrete (sectional), and parameterized representations of the aerosol size distribution. Simulations of coagulation and condensation are performed with the three models for clear, hazy, and urban atmospheric conditions. Relative accuracies and computational costs are compared. Reference for the comparison is the continuous approach. The results of the study provide useful information for the selection of an aerosol model, depending on the accuracy requirements and computational constraints associated with a specific application.
Dynamic Conditional Correlation - A Simple Class of Multivariate GARCH Models
Engle, Robert F
2000-01-01T23:59:59.000Z
Multivariate Simultaneous GARCH," Econometric Theory 11,and Joseph Mezrich, (1996) "GARCH for Groups," Risk August,SIMPLE CLASS OF MULTIVARIATE GARCH MODELS BY ROBERT F. ENGLE
advanced dynamic models: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
. . . . 18 3.4.1 Heat Exchanger - Code description . . . . . . . . . . . . . . . 18 3.4.2 Simulation ResultsADVANCED POWER PLANT MODELING WITH APPLICATIONS TO THE ADVANCED BOILING...
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.
Representation of Dormant and Active Microbial Dynamics for Ecosystem Modeling
Wang, Gangsheng [ORNL; Mayes, Melanie [ORNL; Gu, Lianhong [ORNL; Schadt, Christopher Warren [ORNL
2014-01-01T23:59:59.000Z
Dormancy is an essential strategy for microorganisms to cope with environmental stress. However, global ecosystem models typically ignore microbial dormancy, resulting in notable model uncertainties. To facilitate the consideration of dormancy in these large-scale models, we propose a new microbial physiology component that works for a wide range of substrate availabilities. This new model is based on microbial physiological states and the major parameters are the maximum specific growth and maintenance rates of active microbes and the ratio of dormant to active maintenance rates. A major improvement of our model over extant models is that it can explain the low active microbial fractions commonly observed in undisturbed soils. Our new model shows that the exponentially-increasing respiration from substrate-induced respiration experiments can only be used to determine the maximum specific growth rate and initial active microbial biomass, while the respiration data representing both exponentially-increasing and non-exponentially-increasing phases can robustly determine a range of key parameters including the initial total live biomass, initial active fraction, the maximum specific growth and maintenance rates, and the half-saturation constant. Our new model can be incorporated into existing ecosystem models to account for dormancy in microbially-driven processes and to provide improved estimates of microbial activities.
Relativistic Dynamical Collapse Model for a Scalar Field
Philip Pearle
2014-04-26T23:59:59.000Z
A natural generalization of the CSL (Continuous Spontaneous Localization) theory of dynamical collapse is applied to a relativistic quantum scalar field $\\phi({\\bf x},t)$. It is shown that the modified Schr\\"odinger equation is relativistically invariant, that the probabilities associated to all possible values of the classical scalar random field $w({\\bf x},t)$ (which determines the eventual state of collapse) add up to 1, that there is no energy production out of the vacuum and, in the limit of large time, the collapse is toward eigenstates of $\\phi({\\bf x},0)$.
Sandia National Laboratories: structural-dynamics modeling capability
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1developmentturbineredox-activeNational Solar Thermalssls exhibitstructural-dynamics
Zhu, Ling; Mao, Shude; Peng, Eric W; Liu, Chengze; Caldwell, Nelson; Li, Biao; Blakeslee, John P; Cote, Patrick; Cuillandre, Jean-Charles; Durrell, Patrick; Emsellem, Eric; Ferrarese, Laura; Gwyn, Stephen; Jordan, Andres; Lancon, Ariane; Mei, Simona; Munoz, Roberto; Puzi, Thomas
2014-01-01T23:59:59.000Z
We study the dynamics of the giant elliptical galaxy M87 from the central to the outermost regions with the made-to-measure (M2M) method. We use a new catalogue of 922 globular cluster line-of- sight velocities extending to a projected radius of 180 kpc (equivalent to 25 M87 effective radii), and SAURON integral field unit data within the central 2.4 kpc. 263 globular clusters, mainly located beyond 40 kpc, are newly observed by the Next Generation Virgo Survey (NGVS). For the M2M modelling, the gravitational potential is taken as a combination of a luminous matter potential with a constant stellar mass-to-light ratio and a dark matter potential modelled as a logarithmic potential. Our best dynamical model returns a stellar mass-to-light ratio in the I band of M/LI = 6.0(+ -0.3) M_sun/L_sun with a dark matter potential scale velocity of 591(+ -50) km/s and scale radius of 42(+ -10) kpc. We determine the total mass of M87 within 180 kpc to be (1.5 + - 0.2) 10^13 M_sun. The mass within 40 kpc is smaller than pr...
Climate-Soil-Vegetation Control on Groundwater Table Dynamics and its Feedbacks in a Climate Model
Leung, Lai-Yung R.; Huang, Maoyi; Qian, Yun; Liang, Xu
2010-01-29T23:59:59.000Z
Among the three dynamically linked branches of the water cycle, including atmospheric, surface, and subsurface water, groundwater is the largest reservoir and an active component of the hydrologic system. Because of the inherent slow response time, groundwater may be particularly relevant for long time-scale processes such as multi-years or decadal droughts. This study uses regional climate simulations with and without surface water – groundwater interactions for the conterminous U.S. to assess the influence of climate, soil, and vegetation on groundwater table dynamics, and its potential feedbacks to regional climate. Analysis shows that precipitation has a dominant influence on the spatial and temporal variations of groundwater table depth (GWT). The simulated GWT is found to decrease sharply with increasing precipitation. Our simulation also shows some distinct spatial variations that are related to soil porosity and hydraulic conductivity. Vegetation properties such as minimum stomatal resistance, and root depth and fraction are also found to play an important role in controlling the groundwater table. Comparing two simulations with and without groundwater table dynamics, we find that groundwater table dynamics mainly influences the partitioning of soil water between the surface (0 – 0.5 m) and subsurface (0.5 – 5 m) rather than total soil moisture. In most areas, groundwater table dynamics increases surface soil moisture at the expense of the subsurface, except in regions with very shallow groundwater table. The change in soil water partitioning between the surface and subsurface is found to strongly correlate with the partitioning of surface sensible and latent heat fluxes. The evaporative fraction (EF) is generally higher during summer when groundwater table dynamics is included. This is accompanied by increased cloudiness, reduced diurnal temperature range, cooler surface temperature, and increased cloud top height. Although both convective and non-convective precipitation are enhanced, the higher EF changes the partitioning to favor more non-convective precipitation, but this result could be sensitive to the convective parameterization used. Compared to simulations without groundwater table dynamics, the dry bias in the summer precipitation is slightly reduced over the central and eastern U.S. Groundwater table dynamics can provide important feedbacks to atmospheric processes, and these feedbacks are stronger in regions with deeper groundwater table, because the interactions between surface and subsurface are weak when the groundwater table is deep. This increases the sensitivity of surface soil moisture to precipitation anomalies, and therefore enhances land surface feedbacks to the atmosphere through changes in soil moisture and evaporative fraction. By altering the groundwater table depth, land use change and groundwater withdrawal can alter land surface response and feedback to the climate system.
Dynamical Models Explaining Social Balance and Evolution of Cooperation
De Leenheer, Patrick
factions. Examples of such a split abound: revolutionaries versus an old regime, Republicans versus such factions emerge. An earlier model could explain the formation of such factions if reputations were assumed to split into two factions. In addition, the alternative model may lead to cooperation when faced
Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.
2013-07-31T23:59:59.000Z
A one-dimensional, non-isothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid-sorbent carbon dioxide (CO{sub 2}) capture using Aspen Custom Modeler® (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributor have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO{sub 2} capture rate and flue gas outlet temperatures have been studied by simulating typical disturbances such as change in the temperature, flowrate, and composition of the incoming flue gas from pulverized coal-fired power plants. In control studies, the performance of a proportional-integral-derivative (PID) controller, feedback-augmented feedforward controller, and linear model predictive controller (LMPC) are evaluated for maintaining the overall CO{sub 2} capture rate at a desired level in the face of typical disturbances.
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.
Dynamic modeling and transient studies of a solid-sorbent adsorber for CO{sub 2} capture
Modekurti, Srinivasarao [WVU; Bhattacharyya, Debangsu [WVU; Zitney, Stephen E. [U.S. DOE
2012-01-01T23:59:59.000Z
The U.S. Department of Energy’s Carbon Capture Simulation Initiative (CCSI) is dedicated to accelerating the commercialization of carbon capture technologies from discovery to development, demonstration, and ultimately the widespread deployment to hundreds of power plants. In this multi-lab initiative in partnership with academic and industrial institutions, the National Energy Technology Laboratory (NETL) leads the development of a multi-scale modeling and simulation toolset for rapid evaluation and deployment of carbon capture systems. One element of the CCSI is focused on optimizing the operation and control of carbon capture systems since this can have a significant impact on the extent and the rate at which commercial-scale capture processes will be scaled-up, deployed, and used in the years to come. Capture processes must be capable of operating over a wide range of transient events, malfunctions, and disturbances, as well as under uncertainties. As part of this work, dynamic simulation and control models, methods, and tools are being developed for CO{sub 2} capture and compression processes and their integration with a baseline commercial-scale supercritical pulverized coal (SCPC) power plant. Solid-sorbent-based post-combustion capture technology was chosen as the first industry challenge problem for CCSI because significant work remains to define and optimize the reactors and processes needed for successful sorbent capture systems. Sorbents offer an advantage because they can reduce the regeneration energy associated with CO{sub 2} capture, thus reducing the parasitic load. In view of this, the current paper focuses on development of a dynamic model of a solid-sorbent CO{sub 2} adsorber-reactor and an analysis of its transient performance with respect to several typical process disturbances. A one-dimensional, non-isothermal, pressure-driven dynamic model of a two-stage bubbling fluidized bed (BFB) adsorber-reactor is developed in Aspen Custom Modeler (ACM). The BFB stages are of overflow-type configuration where the solids leave the stage by flowing over the overflow-weir. Each bed is divided into three regions, namely emulsion, bubble, and cloud-wake regions. In all three regions, the model considers mass and energy balances. Along with the models of the BFB stages, models of other associated hardware are developed and integrated in a single flowsheet. A valid pressure-flow network is developed and a lower-level control system is designed so that the overall CO{sub 2} capture can be maintained at a desired level in face of the typical disturbances. The dynamic model is used for studying the transient responses of a number of important process variables as a result of the disturbances that are typical of post-combustion CO{sub 2} capture processes.
Theoretical modeling of propagation of magneto-acoustic waves in magnetic regions below sunspots
E. Khomenko; A. Kosovichev; M. Collados; K. Parchevsky; V. Olshevsky
2008-12-10T23:59:59.000Z
We use 2D numerical simulations and eikonal approximation, to study properties of MHD waves traveling below the solar surface through the magnetic structure of sunspots. We consider a series of magnetostatic models of sunspots of different magnetic field strengths, from 10 Mm below the photosphere to the low chromosphere. The purpose of these studies is to quantify the effect of the magnetic field on local helioseismology measurements by modeling waves excited by sub-photospheric sources. Time-distance propagation diagrams and wave travel times are calculated for models of various field strength and compared to the non-magnetic case. The results clearly indicate that the observed time-distance helioseismology signals in sunspot regions correspond to fast MHD waves. The slow MHD waves form a distinctly different pattern in the time-distance diagram, which has not been detected in observations. The numerical results are in good agreement with the solution in the short-wavelength (eikonal) approximation, providing its validation. The frequency dependence of the travel times is in a good qualitative agreement with observations.
Dynamical phase space from a SO(d,d) matrix model
Athanasios Chatzistavrakidis
2014-07-25T23:59:59.000Z
It is shown that a matrix model with SO($d,d$) global symmetry is derived from a generalized Yang-Mills theory on the standard Courant algebroid. This model keeps all the positive features of the well-studied type IIB matrix model, and it has many additional welcome properties. We show that it does not only capture the dynamics of spacetime, but it should be associated with the dynamics of phase space. This is supported by a large set of classical solutions of its equations of motion, which corresponds to phase spaces of noncommutative curved manifolds and points to a new mechanism of emergent gravity. The model possesses an additional symmetry that exchanges positions and momenta, in analogy to quantum mechanics. It is argued that the emergence of phase space in the model is an essential feature for the investigation of the precise relation of matrix models to string theory and quantum gravity.
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.
Wang, Yuqing
, and development of regional earth system models. It is believed that with the demonstrated credibility of RCMs
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.
Polarimetric modeling of corotating interaction regions (CIRs) threading massive-star winds
Ignace, R; Proulx-Giraldeau, F
2015-01-01T23:59:59.000Z
Massive star winds are complex radiation-hydrodynamic (sometimes magnetohydrodynamic) outflows that are propelled by their enormously strong luminosities. The winds are often found to be structured and variable, but can also display periodic or quasi-periodic behavior in a variety of wind diagnostics. The regular variations observed in putatively single stars, especially in UV wind lines, have often been attributed to corotating interaction regions (CIRs) like those seen in the solar wind. We present light curves for variable polarization from winds with CIR structures. We develop a model for a time-independent CIR based on a kinematical description. Assuming optically thin electron scattering, we explore the range of polarimetric light curves that result as the curvature, latitude, and number of CIRs are varied. We find that a diverse array of variable polarizations result from an exploration of cases. The net polarization from an unresolved source is weighted more toward the inner radii of the wind. Given t...
Ris-R-1400(EN) Dynamic wind turbine models in power
RisÃ¸-R-1400(EN) Dynamic wind turbine models in power system simulation tool DIgSILENT Anca D December 2003 #12;#12;Contents Preface 5 1 Introduction 6 2 Wind turbine modelling in DIgSILENT 7 2.1 Power converters 14 2.2.3 Transformer 16 2.3 DSL models of wind turbine in DIgSILENT 18 2.3.1 Initialisation issues
Dynamics of holographic vacuum energy in the DGP model
Xing Wu; Rong-Gen Cai; Zong-Hong Zhu
2007-12-21T23:59:59.000Z
We consider the evolution of the vacuum energy in the DGP model according to the holographic principle under the assumption that the relation linking the IR and UV cut-offs still holds in this scenario. The model is studied when the IR cut-off is chosen to be the Hubble scale $H^{-1}$, the particle horizon $R_{\\rm ph}$ and the future event horizon $R_{\\rm eh}$, respectively. And the two branches of the DGP model are also taken into account. Through numerical analysis, we find that in the cases of $H^{-1}$ in the (+) branch and $R_{\\rm eh}$ in both branches, the vacuum energy can play the role of dark energy. Moreover, when considering the combination of the vacuum energy and the 5D gravity effect in both branches, the equation of state of the effective dark energy may cross -1, which may lead to the Big Rip singularity. Besides, we constrain the model with the Type Ia supernovae and baryon oscillation data and find that our model is consistent with current data within $1\\sigma$, and that the observations prefer either a pure holographic dark energy or a pure DGP model
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
Denny, Mark
a dynamically matched 1/25-scale physical model in a laboratory flume. In experiments with kelp mimics, waves a dynamically scaled laboratory model Johanna H. Rosman,a,* Mark W. Denny,b Robert B. Zeller,c Stephen G between model kelp and water under waves increased wake generation of turbulence, resulting in turbulent
Huang, Xun
19th. AIAA-CEAS Aeroacoutics Conference, May 28th 2013, Berlin Dynamic Modeling and Numerical was presented in this paper. By this control-oriented model, transient dynamic process of multi-physics coupling problem in a progressive wave tube could be approximately studied. The proposed model is verified
Meng, Zhiyong
degraded). As in Part I, where the perfect model assumption was utilized, most analysis error reduction of significant model errors due to physical parameterizations by assimilating synthetic sounding and surfaceTests of an Ensemble Kalman Filter for Mesoscale and Regional-Scale Data Assimilation. Part II
Nonlinear force-free models for the solar corona I. Two active regions with very different structure
S. Regnier; E. R. Priest
2007-03-29T23:59:59.000Z
With the development of new instrumentation providing measurements of solar photospheric vector magnetic fields, we need to develop our understanding of the effects of current density on coronal magnetic field configurations. The object is to understand the diverse and complex nature of coronal magnetic fields in active regions using a nonlinear force-free model. From the observed photospheric magnetic field we derive the photospheric current density for two active regions: one is a decaying active region with strong currents (AR8151), and the other is a newly emerged active region with weak currents (AR8210). We compare the three-dimensional structure of the magnetic fields for both active region when they are assumed to be either potential or nonlinear force-free. The latter is computed using a Grad-Rubin vector-potential-like numerical scheme. A quantitative comparison is performed in terms of the geometry, the connectivity of field lines, the magnetic energy and the magnetic helicity content. For the old decaying active region the connectivity and geometry of the nonlinear force-free model include strong twist and strong shear and are very different from the potential model. The twisted flux bundles store magnetic energy and magnetic helicity high in the corona (about 50 Mm). The newly emerged active region has a complex topology and the departure from a potential field is small, but the excess magnetic energy is stored in the low corona and is enough to trigger powerful flares.
The dynamics of a low-order coupled ocean-atmosphere model
L. van Veen; F. Verhulst; T. Opsteegh
1998-12-16T23:59:59.000Z
A system of five ordinary differential equations is studied which combines the Lorenz-84 model for the atmosphere and a box model for the ocean. The behaviour of this system is studied as a function of the coupling parameters. For most parameter values, the dynamics of the atmosphere model is dominant. For a range of parameter values, competing attractors exist. The Kaplan-Yorke dimension and the correlation dimension of the chaotic attractor are numerically calculated and compared to the values found in the uncoupled Lorenz model. In the transition from periodic behaviour to chaos intermittency is observed. The intermittent behaviour occurs near a Neimark-Sacker bifurcation at which a periodic solution loses its stability. The length of the periodic intervals is governed by the time scale of the ocean component. Thus, in this regime the ocean model has a considerable influence on the dynamics of the coupled system.
Grauwin, S; Jensen, P
2009-01-01T23:59:59.000Z
In his 1971's Dynamic Models of Segregation paper, the economist Thomas C. Schelling showed that a small preference for one's neighbors to be of the same color could lead to total segregation, even if total segregation does not correspond to individual preferences and to a residential configuration maximizing the collective utility. The present work is aimed at deepening the understanding of the properties of dynamic models of segregation based on Schelling's hypotheses. Its main contributions are (i) to offer a comprehensive and up-to-date review of this family of models; (ii) to provide an analytical solution to the most general form of this model under rather general assumptions; to the best of our knowledge, such a solution did not exist so far; (iii) to analyse the effect of two devices aimed at decreasing segregation in such a model.
Snyder, M.A.; Kueppers, L.M.; Sloan, L.C.; Cavan, D.C.; Jin, J.; Kanamaru, H.; Miller, N.L.; Tyree, M.; Du, H.; Weare, B.
2006-05-01T23:59:59.000Z
In the western United States, more than 30,500 square miles has been converted to irrigated agriculture and urban areas. This study compares the climate responses of four regional climate models (RCMs) to these past land-use changes. The RCMs used two contrasting land cover distributions: potential natural vegetation, and modern land cover that includes agriculture and urban areas. Three of the RCMs represented irrigation by supplementing soil moisture, producing large decreases in August mean (-2.5 F to -5.6 F) and maximum (-5.2 F to -10.1 F) 2-meter temperatures where natural vegetation was converted to irrigated agriculture. Conversion to irrigated agriculture also resulted in large increases in relative humidity (9 percent 36 percent absolute change). Only one of the RCMs produced increases in summer minimum temperature. Converting natural vegetation to urban land cover produced modest but discernable climate effects in all models, with the magnitude of the effects dependent upon the preexisting vegetation type. Overall, the RCM results indicate that land use change impacts are most pronounced during the summer months, when surface heating is strongest and differences in surface moisture between irrigated land and natural vegetation are largest. The irrigation effect on summer maximum temperatures is comparable in magnitude (but opposite in sign) to predicted future temperature change due to increasing greenhouse gas concentrations.
A Predator-Prey Model with Disease Dynamics Chris Flake
Logan, David
a diseased fish population and their predators. Analysis of the system is performed to determine among the Tilapia fish of the Salton Sea and their predator, the pelican. This model is of interest deaths not only among the fish themselves, but also in the pelican population. Studies have indicated
DYNAMIC PHASORS IN MODELING, ANALYSIS AND CONTROL OF ENERGY
StankoviÃ¦, Aleksandar
in: power electronics, electric drives and power systems. NEU Energy Processing Laboratory (1994) is a confluence of research and educational efforts: 1. Areas: power electronics, electric drives and power (ONR YIP) Systems Power Drives Electric Electronics Adaptive Converters Resonant Modeling Load
Modelling the dynamical evolution of the Bootes dwarf spheroidal galaxy
M. Fellhauer; M. I. Wilkinson; N. W. Evans; V. Belokurov; M. J. Irwin; G. Gilmore; D. B. Zucker; J. T. Kleyna
2008-01-17T23:59:59.000Z
We investigate a wide range of possible evolutionary histories for the recently discovered Bootes dwarf spheroidal galaxy, a Milky Way satellite. By means of N-body simulations we follow the evolution of possible progenitor galaxies of Bootes for a variety of orbits in the gravitational potential of the Milky Way. The progenitors considered cover the range from dark-matter-free star clusters to massive, dark-matter dominated outcomes of cosmological simulations. For each type of progenitor and orbit we compare the observable properties of the remnant after 10 Gyr with those of Bootes observed today. Our study suggests that the progenitor of Bootes must have been, and remains now, dark matter dominated. In general our models are unable to reproduce the observed high velocity dispersion in Bootes without dark matter. Our models do not support time-dependent tidal effects as a mechanism able to inflate significantly the internal velocity dispersion. As none of our initially spherical models is able to reproduce the elongation of Bootes, our results suggest that the progenitor of Bootes may have had some intrinsic flattening. Although the focus of the present paper is the Bootes dwarf spheroidal, these models may be of general relevance to understanding the structure, stability and dark matter content of all dwarf spheroidal galaxies.
Modeling Climate Dynamically James Walsh and Richard McGehee
Wilmer, Elizabeth
to tropical latitudes, leaving a narrow strip of open ocean water about the equator? Can mathematical models and present day evidence. Global climate is determined by the radiation balance of the planet. The Earth warms through the absorption of incoming solar radiation (or insolation). Due to the shortwave nature
Silva et al. Modelling cyanobacteria dynamics in urban lakes
Paris-Sud XI, UniversitÃ© de
watershed hydrologic modelling and high frequency data collection Talita SILVA*, Brigitte VINÃ?ON several essential functions for the cities such as storing rainwater and providing recreation spaces with high-frequency data collected in Lake Enghien. In the second part, we propose a methodology to connect
physics/0512181 Modelling dynamics of samples exposed to
not only the sample but also the optical elements of the FEL beamline. Radiation damage by photons from December 2005 Abstract: We apply Boltzmann equations for modelling the radiation damage in samples. Rapid progress of radiation damage in these samples prevents an accurate determination
Equilibrium model with default and insider's dynamic information Luciano Campi
Paris-Sud XI, UniversitÃ© de
DanilovaÂ§ August 3, 2011 Abstract We consider an equilibrium model `a la Kyle-Back for a defaultable claim, London School of Economics, u.cetin@lse.ac.uk. Â§ Department of Mathematics, London School of Economics, a.danilova
Lurking Pathway Prediction And Pathway ODE Model Dynamic Analysis
Zhang, Rengjing
2013-11-18T23:59:59.000Z
regulated proteins in the transduction pro- cess. And by modeling the CCL2 pathway in MTB infected cells, J N K , cM Y C and P LC showed as the most significant modules. Hence, the drug treatments inhibit- ing J N K , cM Y C and P LC would effectively...
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.
Hawai'i at Manoa, University of
physiologically structured tuna population dynamics in their ecosystem Olivier Maury * IRD (Institut de Recherche by the organisms are modelled according to the DEB (dynamic energy budget) theory (Kooijmann, 2000) and the size-structured- mental variability and fishing on the structure and dynamics of pe- lagic ecosystems. APECOSM uses a size
Modeling the dynamics of tidally-interacting binary neutron stars up to merger
Sebastiano Bernuzzi; Alessandro Nagar; Tim Dietrich; Thibault Damour
2014-12-15T23:59:59.000Z
We propose an effective-one-body (EOB) model that describes the general relativistic dynamics of neutron star binaries from the early inspiral up to merger. Our EOB model incorporates an enhanced attractive tidal potential motivated by recent analytical advances in the post-Newtonian and gravitational self-force description of relativistic tidal interactions. No fitting parameters are introduced for the description of tidal interaction in the late, strong-field dynamics. We compare the model dynamics (described by the gauge invariant relation between binding energy and orbital angular momentum), and the gravitational wave phasing, with new high-resolution multi-orbit numerical relativity simulations of equal-mass configurations with different equations of state. We find agreement essentially within the uncertainty of the numerical data for all the configurations. Our model is the first semi-analytical model which captures the tidal amplification effects close to merger. It thereby provides the most accurate analytical representation of binary neutron star dynamics and waveforms currently available.
Modeling the dynamics of tidally-interacting binary neutron stars up to merger
Sebastiano Bernuzzi; Alessandro Nagar; Tim Dietrich; Thibault Damour
2015-02-18T23:59:59.000Z
The data analysis of the gravitational wave signals emitted by coalescing neutron star binaries requires the availability of an accurate analytical representation of the dynamics and waveforms of these systems. We propose an effective-one-body (EOB) model that describes the general relativistic dynamics of neutron star binaries from the early inspiral up to merger. Our EOB model incorporates an enhanced attractive tidal potential motivated by recent analytical advances in the post-Newtonian and gravitational self-force description of relativistic tidal interactions. No fitting parameters are introduced for the description of tidal interaction in the late, strong-field dynamics. We compare the model energetics and the gravitational wave phasing with new high-resolution multi-orbit numerical relativity simulations of equal-mass configurations with different equations of state. We find agreement within the uncertainty of the numerical data for all configurations. Our model is the first semi-analytical model which captures the tidal amplification effects close to merger. It thereby provides the most accurate analytical representation of binary neutron star dynamics and waveforms currently available.
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...
Development of a Dynamic DOE Calibration Model | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat Pump Models |Conduct, Parent CompanyaUSAMP AMDHeavy Duty TrucksDevelopment
Held, M
2015-01-01T23:59:59.000Z
A lattice Boltzmann method (LBM) approach to the Charney-Hasegawa-Mima (CHM) model for adiabatic drift wave turbulence in magnetised plasmas, is implemented. The CHM-LBM model contains a barotropic equation of state for the potential, a force term including a cross-product analogous to the Coriolis force in quasigeostrophic models, and a density gradient source term. Expansion of the resulting lattice Boltzmann model equations leads to cold-ion fluid continuity and momentum equations, which resemble CHM dynamics under drift ordering. The resulting numerical solutions of standard test cases (monopole propagation, stable drift modes and decaying turbulence) are compared to results obtained by a conventional finite difference scheme that directly discretizes the CHM equation. The LB scheme resembles characteristic CHM dynamics apart from an additional shear in the density gradient direction. The occuring shear reduces with the drift ratio and is ascribed to the compressible limit of the underlying LBM.
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
DYNAMIC MODEL OF AN INDUSTRIAL HEAT PUMP USING WATER AS REFRIGERANT
Paris-Sud XI, UniversitÃ© 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
Wagner, Diane
of surface energy balance [Liu et al., 2005], soil thermal and hydrological regimes [MacKay, 1995; Burn, 1998A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil not comprehensively considered how interactions among fire disturbance, soil environmental conditions
Soft-ratchet modeling of slow dynamics in the nonlinear resonant response of sedimentary
Soft-ratchet modeling of slow dynamics in the nonlinear resonant response of sedimentary rocks of Physics 0-7354-0330-9/06/$23.00 CREDIT LINE (BELOW) TO BE INSERTED ONLY ON THE FIRST PAGE OF THE #12;SOFT-RATCHET
Chen, Qingyan "Yan"
1 Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink, USA, Fax: 617-432-4122, Abstract Many ice rink arenas have ice resurfacing equipment that uses fossil temperature distributions in ice rinks. The numerical results agree reasonably with the corresponding
A Note on Dynamic Data Driven Wildfire Modeling , L.P. Franca1
Douglas, Craig C.
of the interactions of fire, weather, and fuel, driven by remote sensing data of fire location and land surfaceA Note on Dynamic Data Driven Wildfire Modeling J. Mandel1 , M. Chen1 , L.P. Franca1 , C. Johns1 of Colorado Denver, Denver, CO 80217-3364, USA 2 National Center for Atmospheric Research, Boulder, CO 80307
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
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
A model for vendor selection and dynamic evaluation Raffele Iannone1
Paris-Sud XI, UniversitÃ© de
A model for vendor selection and dynamic evaluation Raffele Iannone1 , Salvatore Miranda1 , Stefano with the monitoring and the continuous analysis of the vendor performances. The vendor evaluation process is realised and obtainable benefits. Keywords: Vendor Evaluation, Vendor Selection, AHP, Supply Management 1 Introduction
Modelling of power plant dynamics and uncertainties for robust control synthesis *
Ray, Asok
-Kuo Weng, Asok Ray and Xiaowen Dai Mechanical Engineering Department, The Pennsylvania State University systems synthesis. In lieu of the actual plant data, mathematical models of computational fluid dynamics of Mechanical Engineering, The Pennsylvania State University, 137 Reber Building, University Park, PA 16802
EMULATING A GRAVITY MODEL TO INFER THE SPATIOTEMPORAL DYNAMICS OF AN INFECTIOUS DISEASE
BjÃ¸rnstad, Ottar Nordal
EMULATING A GRAVITY MODEL TO INFER THE SPATIOTEMPORAL DYNAMICS OF AN INFECTIOUS DISEASE Roman grid. Â· Use pre-calculated matrices {Mtk}. GP-EMULATOR - BASED APPROACH Â· Based on constructing a new (proportions of zeros) on a pre-selected grid of parameters. Â· Second stage: We make inference based
Modeling Malware Propagation in Networks of Smart Cell Phones with Spatial Dynamics
Sikdar, Biplab
Modeling Malware Propagation in Networks of Smart Cell Phones with Spatial Dynamics Krishna and worm attacks tar- geted at cell phones have have bought to the forefront the seriousness of the security threat to this increasingly popular means of communication. The ability of smart cell phones
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
UNCORRECTED 2 Models of natural and human dynamics in forest landscapes
Monticino, Michael
protected areas, though they differ in the specifics of vegetation and land 23 use. In the Texas sitesUNCORRECTED PROOF 1 2 Models of natural and human dynamics in forest landscapes: 3 Cross natural and human systems across sites and cultures through a process of simplification and 17 abstraction
A Combined Molecular Dynamics and Diffusion Model of Single Proton Conduction through Gramicidin
Schumaker, Mark
A Combined Molecular Dynamics and Diffusion Model of Single Proton Conduction through Gramicidin through the gramicidin pore is described by a potential of mean force and diffusion coefficient obtained in the hydrogen bonding structure of pore waters without an excess proton. Proton entrance and exit were
Energy dynamics and modeled evapotranspiration from a wet tropical forest in Costa Rica
Energy dynamics and modeled evapotranspiration from a wet tropical forest in Costa Rica H). #12;1. Introduction The energy balance of tropical forests is complex due to feedback mechanisms among.W. Loeschera, *, H.L. Gholza,b , J.M. Jacobsc , S.F. Oberbauerd,e a School of Forest Resources and Conservation
Bayesian Emulation of Complex Multi-Output and Dynamic Computer Models
Oakley, Jeremy
Bayesian Emulation of Complex Multi-Output and Dynamic Computer Models Stefano Conti Anthony O the case). In particular, standard Monte Carlo-based methods of sensitivity analysis (extensively reviewed'Hagan, 2002), offering substantial efficiency gains over standard Monte Carlo-based meth- ods. These authors
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
SURFACE ELASTICITY MODELS FOR STATIC AND DYNAMIC RESPONSE OF NANOSCALE BEAMS
Phani, A. Srikantha
SURFACE ELASTICITY MODELS FOR STATIC AND DYNAMIC RESPONSE OF NANOSCALE BEAMS by Chang Liu B) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) February 2010 Â© Chang Liu, 2010 #12;ii Abstract Nanoscale beam of nanoscale beams. The objective is to provide NEMS designers with an efficient set of tools that can predict
A COMPARISON BETWEEN TWO SIMPLIFIED DYNAMICAL MODELS FOR THE HUMAN GAIT
Llanos, Diego R.
A COMPARISON BETWEEN TWO SIMPLIFIED DYNAMICAL MODELS FOR THE HUMAN GAIT A.Ortega 1 , F.Montoya 1 and J.Finat 2 , MoBiVA Group. 1 ETS Ing. Industrial, Paseo del Cauce, Univ. Valladolid, 47011 Valladolid to a passive approach to maintain the upright position and locomotion with a view to their applications
CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1
Paris-Sud XI, UniversitÃ© de
CT-PET Landmark-based Lung Registration Using a Dynamic Breathing Model S. Chambon1 , A. Moreno1-based registration of CT (at two different instants of the breathing cycle, intermediate expirations) and PET images in order to simulate the instant in the breathing cycle most similar to the PET image and guarantee
Ecological Modelling 180 (2004) 135151 Simulating forest fuel and fire risk dynamics across
He, Hong S.
fuel module tracks fine fuel, coarse fuel and live fuel for each cell on a landscape. Fine fuel age (the oldest age cohorts) in combination with disturbance history. Live fuels, also called canopyEcological Modelling 180 (2004) 135Â151 Simulating forest fuel and fire risk dynamics across
Xin, Jack
an electric field is applied to materials with high resistivity, the dipole moments of the molecules alignIMA Journal of Applied Mathematics (2002) 67, 419Â439 Modelling thermal front dynamics in microwave July 2000; revised on 6 December 2001] The formation and propagation of thermal fronts in a cylindrical
Zachariah, Michael R.
that the generation of SiOHx species from fast gas- phase reactions can significantly degrade film quality. Based conservation equations and a moment-type aerosol dynamics model were formulated for a batch reactor undergoing to impurity diffusion.1 During LPCVD film deposition rates are limited by the gas-phase nucleation
Time Series Prediction by Chaotic Modeling of Nonlinear Dynamical Systems Arslan Basharat+
Central Florida, University of
Inc. Clifton Park, NY, USA arslan.basharat@kitware.com Mubarak Shah+ + University of Central Florida Orlando, FL, USA shah@cs.ucf.edu Abstract We use concepts from chaos theory in order to model nonlinear dynamical systems that exhibit deterministic be- havior. Observed time series from such a system can be em
On the self-similarity assumption in dynamic models for large eddy simulations
Van Den Eijnden, Eric
that the present formulation of the DP is usually incompatible with its under- lying self-similarity assumption SSAOn the self-similarity assumption in dynamic models for large eddy simulations Daniele Carati eddy simulations and their underlying self-similarity assumption is discussed. The interpretation
Coupled Damage and Plasticity Modelling in Transient Dynamic Analysis of Concrete
Coupled Damage and Plasticity Modelling in Transient Dynamic Analysis of Concrete F. Gatuingt Abstract In a concrete structure subjected to an explosion, for example a concrete slab, the material on the same concrete. Computations of split Hopkinson tests on confined concrete, a tensile test with scabbing
Cooling energy demand evaluation by means of regression models obtained from dynamic simulations
Paris-Sud XI, UniversitÃ© de
Cooling energy demand evaluation by means of regression models obtained from dynamic simulations Ph, UniversitÃ© Lyon1, FRANCE ABSTRACT The forecast of the energy heating/cooling demand would be a good indicator between simple and complex methods of evaluating the cooling energy demand we have proposed to use energy
A simplified model of thin layer static/flowing dynamics for granular materials with yield
Paris-Sud XI, UniversitÃ© de
/deposition processes when a layer of particles is flowing over a static layer or near the destabilization and arrestA simplified model of thin layer static/flowing dynamics for granular materials with yield, 75005 Paris, France, 4 ANGE team, INRIA, CETMEF, Lab. J.-L. Lions, Paris, France Abstract We introduce
Building Dynamic Models of Service Compositions With Simulation of Provision Resources
PolitÃ©cnica de Madrid, Universidad
Building Dynamic Models of Service Compositions With Simulation of Provision Resources Dragan of service compositions depends both on the composition structure, and on planning and management of compu- tational resources necessary for provision. Resource constraints on the service provider side have impact
Modeling the dynamics of human hair cycles by a follicular automaton
Goldbeter, Albert
Modeling the dynamics of human hair cycles by a follicular automaton J. Halloy*, B. A. Bernard , G University of Brussels, Brussels, Belgium, May 15, 2000 (received for review December 23, 1999) The hair correspond, respectively, to hair growth, arrest, shedding, and absence before a new anagen phase
Dynamical Systems analysis of an interacting dark energy model in the Brane Scenario
Biswas, Sujay Kr
2015-01-01T23:59:59.000Z
In this paper, we investigate the background dynamics in brane cosmology when dark energy is coupled to dark matter by a suitable interaction. Here we consider an homogeneous and isotropic Friedmann-Robertson-Walker (FRW) brane model and the evolution equations are reduced to an autonomous system by suitable transformation of variables. The nature of critical points are analyzed by evaluating the eigenvalues of linearized Jacobi matrix. Finally, the classical stability of the model is also studied.
Stochastic Dynamic Demand Inventory Models with Explicit Transportation Costs and Decisions
Zhang, Liqing
2011-07-01T23:59:59.000Z
is the policy where several small loads will be dispatched as a single, combined load. From an inventory-modeling perspec- tive, the integrated inventory-transportation problems add dispatch quantities as decision variables to the stochastic dynamic inventory...): The vendor makes the inventory replen- ishment decisions on how much to order from the outside supplier. 2. Pure Outbound Transportation Models (PO): The collection depot makes the delivery schedules of order dispatches to the buyer(s). 3. Integrated...
Experimental results and modeling of a dynamic hohlraum on SATURN
Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J. [Sandia National Labs., Albuquerque, NM (United States); Matuska, W.; Peterson, D.L. [Los Alamos National Lab., NM (United States); MacFarlane, J.J. [Univ. of Wisconsin, Madison, WI (United States); Ryutov, D.D. [Lawrence Livermore National Lab., CA (United States)
1998-06-01T23:59:59.000Z
Experiments were performed at SATURN, a high current z-pinch, to explore the feasibility of creating a hohlraum by imploding a tungsten wire array onto a low-density foam. Emission measurements in the 200--280 eV energy band were consistent with a 110--135 eV Planckian before the target shock heated, or stagnated, on-axis. Peak pinch radiation temperatures of nominally 160 eV were obtained. Measured early time x-ray emission histories and temperature estimates agree well with modeled performance in the 200--280 eV band using a 2D radiation magneto-hydrodynamics code. However, significant differences are observed in comparisons of the x-ray images and 2D simulations.
Membrane Fuzzy Sphere Dynamics in Plane-Wave Matrix Model
Hyeonjoon Shin; Kentaroh Yoshida
2004-09-03T23:59:59.000Z
In plane-wave matrix model, the membrane fuzzy sphere extended in the SO(3) symmetric space is allowed to have periodic motion on a sub-plane in the SO(6) symmetric space. We consider a background configuration composed of two such fuzzy spheres moving on the same sub-plane and the one-loop quantum corrections to it. The one-loop effective action describing the fuzzy sphere interaction is computed up to the sub-leading order in the limit that the mean distance $r$ between two fuzzy spheres is very large. We show that the leading order interaction is of the 1/r^7 type and thus the membrane fuzzy spheres interpreted as giant gravitons really behave as gravitons.
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
Physical Constraints on, and a Model for, the Active Regions in Seyfert Galaxies
Sergei Nayakshin; Fulvio Melia
1997-05-30T23:59:59.000Z
We discuss several physical constraints on the nature of the Active Regions (AR) in Seyfert 1 Galaxies, and show that a plausible model consistent with these constraints is one in which the ARs are magnetically confined and ``fed''. The unique X-ray index of these sources points to a large compactness parameter ($l\\gg 1$). This, together with the conditions required to account for the observed optical depth being close to unity, suggests that the magnetic energy density in the AR should be comparable to the equipartition value in the accretion disk, and that it should be released in a flare-like event above the surface of the cold accretion disk. We consider the various issues pertaining to magnetic flares and attempt to construct a coherent picture, including a reason for the optical depth in the AR being $\\sim 1$, and an understanding of the characteristics of the X-ray reflection component and the power density spectra associated with this high-energy emission.
Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.
2013-08-01T23:59:59.000Z
By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.
Ben-Yakar, Adela
Dynamic Thermal Model of Polymer Electrolyte Membrane (PEM) Fuel Cell Budi Hadisujoto, Rehan Refai to improve the performance of a PEM fuel cell Simulation Results Advanced Power Systems and Controls (GDL) to reduce water saturation Â· Model water transport in PEM fuel cell Contribution: Â· Dynamic
Technical Review of the CENWP Computational Fluid Dynamics Model of the John Day Dam Forebay
Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.
2010-12-01T23:59:59.000Z
The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWP's CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequately configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.
Compartment modeling of dynamic brain PET—The impact of scatter corrections on parameter errors
Häggström, Ida, E-mail: ida.haggstrom@radfys.umu.se; Karlsson, Mikael; Larsson, Anne [Department of Radiation Sciences, Umeå University, Umeå 90187 (Sweden); Schmidtlein, C. Ross [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York 10065 (United States)
2014-11-01T23:59:59.000Z
Purpose: The aim of this study was to investigate the effect of scatter and its correction on kinetic parameters in dynamic brain positron emission tomography (PET) tumor imaging. The 2-tissue compartment model was used, and two different reconstruction methods and two scatter correction (SC) schemes were investigated. Methods: The GATE Monte Carlo (MC) software was used to perform 2 × 15 full PET scan simulations of a voxelized head phantom with inserted tumor regions. The two sets of kinetic parameters of all tissues were chosen to represent the 2-tissue compartment model for the tracer 3?-deoxy-3?-({sup 18}F)fluorothymidine (FLT), and were denoted FLT{sub 1} and FLT{sub 2}. PET data were reconstructed with both 3D filtered back-projection with reprojection (3DRP) and 3D ordered-subset expectation maximization (OSEM). Images including true coincidences with attenuation correction (AC) and true+scattered coincidences with AC and with and without one of two applied SC schemes were reconstructed. Kinetic parameters were estimated by weighted nonlinear least squares fitting of image derived time–activity curves. Calculated parameters were compared to the true input to the MC simulations. Results: The relative parameter biases for scatter-eliminated data were 15%, 16%, 4%, 30%, 9%, and 7% (FLT{sub 1}) and 13%, 6%, 1%, 46%, 12%, and 8% (FLT{sub 2}) for K{sub 1}, k{sub 2}, k{sub 3}, k{sub 4}, V{sub a}, and K{sub i}, respectively. As expected, SC was essential for most parameters since omitting it increased biases by 10 percentage points on average. SC was not found necessary for the estimation of K{sub i} and k{sub 3}, however. There was no significant difference in parameter biases between the two investigated SC schemes or from parameter biases from scatter-eliminated PET data. Furthermore, neither 3DRP nor OSEM yielded the smallest parameter biases consistently although there was a slight favor for 3DRP which produced less biased k{sub 3} and K{sub i} estimates while OSEM resulted in a less biased V{sub a}. The uncertainty in OSEM parameters was about 26% (FLT{sub 1}) and 12% (FLT{sub 2}) larger than for 3DRP although identical postfilters were applied. Conclusions: SC was important for good parameter estimations. Both investigated SC schemes performed equally well on average and properly corrected for the scattered radiation, without introducing further bias. Furthermore, 3DRP was slightly favorable over OSEM in terms of kinetic parameter biases and SDs.
Paris-Sud XI, UniversitÃ© de
European Wind Energy Conference & Exhibition EWEC 2003, Madrid, Spain. Forecasting of Regional Wind. Abstract-Short-term wind power forecasting is recognized nowadays as a major requirement for a secure and economic integration of wind power in a power system. In the case of large-scale integration, end users
Vitaly V. Bulatov; Yuriy V. Vladimirov
2012-06-26T23:59:59.000Z
In this paper, we consider fundamental problems of the dynamics of internal gravity waves. We present analytical and numerical algorithms for calculating the wave fields for a set of values of the parameters, as observed in the ocean. We show that our mathematical models can describe the wave dynamics of the Arctic Basin, taking into account the actual physical characteristics of sea water, topography of its floor, etc. The numerical and analytical results show that the internal gravity waves have a significant effect on underwater sea objects in the Arctic Basin.
E-Print Network 3.0 - active region model Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Collection: Physics 72 The main rationale In the 21st Summary: development in the ASEAN region. Chapter 3: The Space Activities of ASEAN Countries investigates the...
Quantum Dynamical Model for Wave Function Reduction in Classical and Macroscopic Limits
Chang-Pu Sun
1993-03-22T23:59:59.000Z
In this papper, a quantum dynamical model describing the quantum measurement process is presented as an extensive generalization of the Coleman-Hepp model. In both the classical limit with very large quantum number and macroscopic limit with very large particle number in measuring instrument, this model generally realizes the wave packet collapse in quantum measurement as a consequence of the Schrodinger time evolution in either the exactly-solvable case or the non-(exactly-)solvable case. For the latter, its quasi-adiabatic case is explicitly analysed by making use of the high-order adiabatic approximation method and then manifests the wave packet collapse as well as the exactly-solvable case. By highlighting these analysis, it is finally found that an essence of the dynamical model of wave packet collapse is the factorization of the Schrodinger evolution other than the exact solvability. So many dynamical models including the well-known ones before, which are exactly-solvable or not, can be shown only to be the concrete realizations of this factorizability
Simulation of aerosol dynamics: A comparative review of algorithms used in air quality models
Zhang, Y.; Seigneur, C.; Seinfeld, J.H.; Jacobson, M.Z.; Binkowski, F.S.
1999-01-01T23:59:59.000Z
A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, and gas/particle mass transfer. Two major approaches are used in air quality models to represent the particle size distribution: (1) the sectional approach in which the size distribution is discretized into sections and particle properties are assumed to be constant over particle size sections and (2) the modal approach in which the size distribution is approximated by several modes and particle properties are assumed to be uniform in each mode. The results of this study provide useful information to select algorithms to simulate aerosol dynamics in air quality models and to improve the accuracy of existing algorithms.
Vincent Hakim; Alain Karma
1999-03-17T23:59:59.000Z
In a weakly excitable medium, characterized by a large threshold stimulus, the free end of an isolated broken plane wave (wave tip) can either rotate (steadily or unsteadily) around a large excitable core, thereby producing a spiral pattern, or retract causing the wave to vanish at boundaries. An asymptotic analysis of spiral motion and retraction is carried out in this weakly excitable large core regime starting from the free-boundary limit of the reaction-diffusion models, valid when the excited region is delimited by a thin interface. The wave description is shown to naturally split between the tip region and a far region that are smoothly matched on an intermediate scale. This separation allows us to rigorously derive an equation of motion for the wave tip, with the large scale motion of the spiral wavefront slaved to the tip. This kinematic description provides both a physical picture and exact predictions for a wide range of wave behavior, including: (i) steady rotation (frequency and core radius), (ii) exact treatment of the meandering instability in the free-boundary limit with the prediction that the frequency of unstable motion is half the primary steady frequency (iii) drift under external actions (external field with application to axisymmetric scroll ring motion in three-dimensions, and spatial or/and time-dependent variation of excitability), and (iv) the dynamics of multi-armed spiral waves with the new prediction that steadily rotating waves with two or more arms are linearly unstable. Numerical simulations of FitzHug-Nagumo kinetics are used to test several aspects of our results. In addition, we discuss the semi-quantitative extension of this theory to finite cores and pinpoint mathematical subtleties related to the thin interface limit of singly diffusive reaction-diffusion models.
Boyer, Edmond
.Ekstrom@uea.ac.uk Abstract To aid assessments of the impact of climate change on water related activities in the case study on the impacts of climate change on specific water management activities (Kilsby, 2007). Uncertainties linked, temperature, rainfall, Europe Introduction As climate model projections are often used in climate change
Imada, S.; Shimizu, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa 252-5210 (Japan); Hara, H.; Watanabe, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka-shi, Tokyo 181-8588 (Japan); Murakami, I. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Harra, L. K. [UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Zweibel, E. G. [Department of Astronomy, University of Wisconsin-Madison, 475 N Charter Street, Madison, WI 53706 (United States)
2011-12-10T23:59:59.000Z
We previously found a temperature-dependent upflow in the dimming region following a coronal mass ejection observed by the Hinode EUV Imaging Spectrometer (EIS). In this paper, we reanalyzed the observations along with previous work on this event and provided boundary conditions for modeling. We found that the intensity in the dimming region dramatically drops within 30 minutes from the flare onset, and the dimming region reaches the equilibrium stage after {approx}1 hr. The temperature-dependent upflows were observed during the equilibrium stage by EIS. The cross-sectional area of the flux tube in the dimming region does not appear to expand significantly. From the observational constraints, we reconstructed the temperature-dependent upflow by using a new method that considers the mass and momentum conservation law and demonstrated the height variation of plasma conditions in the dimming region. We found that a super-radial expansion of the cross-sectional area is required to satisfy the mass conservation and momentum equations. There is a steep temperature and velocity gradient of around 7 Mm from the solar surface. This result may suggest that the strong heating occurred above 7 Mm from the solar surface in the dimming region. We also showed that the ionization equilibrium assumption in the dimming region is violated, especially in the higher temperature range.
M. V. Ivanov; M. B. Barbaro; J. A. Caballero; A. N. Antonov; E. Moya de Guerra; M. K. Gaidarov
2008-02-29T23:59:59.000Z
The superscaling analysis using the scaling function obtained within the coherent density fluctuation model is extended to calculate charge-changing neutrino and antineutrino scattering on $^{12}$C at energies from 1 to 2 GeV not only in the quasielastic but also in the delta excitation region. The results are compared with those obtained using the scaling functions from the relativistic Fermi gas model and from the superscaling analysis of inclusive scattering of electrons from nuclei.
Joshua H. Cooperman
2014-06-17T23:59:59.000Z
The causal dynamical triangulations approach aims to construct a quantum theory of gravity as the continuum limit of a lattice-regularized model of dynamical geometry. A renormalization group scheme--in concert with finite size scaling analysis--is essential to this aim. Formulating and implementing such a scheme in the present context raises novel and notable conceptual and technical problems. I explored these problems, and, building on standard techniques, suggested potential solutions in the first paper of this two-part series. As an application of these solutions, I now propose a renormalization group scheme for causal dynamical triangulations. This scheme differs significantly from that studied recently by Ambjorn, Gorlich, Jurkiewicz, Kreienbuehl, and Loll.
Du, Ruoyang; Student Member; IEEE; Robertson, Paul
2014-12-18T23:59:59.000Z
BH curves at frequencies up to several kilohertz. B. Application of the Dynamic Jiles-Atherton Model to the Magnetic Loss of a PMSM (BLDC motor) According to Guo’s review paper, empirical formulae have been derived to model the magnetic properties... of the conventional time stepped FEM [11], [26], [27] to utilize the proposed dynamic Jiles-Atherton model to estimate the magnetic power loss in a PMSM. More mathematical work needs to be done to make the dynamic Jiles-Atherton model and time stepped FEM...
Sub-national TIMES model for analyzing regional future use of Biomass and Biofuels in France and
Boyer, Edmond
1 Sub-national TIMES model for analyzing regional future use of Biomass and Biofuels in France Introduction Renewable energy sources such as biomass and biofuels are increasingly being seen as important of biofuels on the final consumption of energy in transport should be 10%. The long-term target is to reduce
A MODEL FOR THE STRENGTH OF THE AS-DEPOSITED REGIONS OF LOW-ALLOY STEEL WELD METALS
Cambridge, University of
true average strain ~ true plastic strain in softer phase of a dual-phase steel ~I true plastic strain in harder phase of a dual-phase steel UTS true strain at ultimate tensile stress y true strain at yieldingCHAPTER 5 A MODEL FOR THE STRENGTH OF THE AS-DEPOSITED REGIONS OF LOW-ALLOY STEEL WELD METALS 5
Aeroelastic Modeling of Offshore Turbines and Support Structures in Hurricane-Prone Regions (Poster)
Damiani, R.
2014-03-01T23:59:59.000Z
US offshore wind turbines (OWTs) will likely have to contend with hurricanes and the associated loading conditions. Current industry standards do not account for these design load cases (DLCs), thus a new approach is required to guarantee that the OWTs achieve an appropriate level of reliability. In this study, a sequentially coupled aero-hydro-servo-elastic modeling technique was used to address two design approaches: 1.) The ABS (American Bureau of Shipping) approach; and 2.) The Hazard Curve or API (American Petroleum Institute) approach. The former employs IEC partial load factors (PSFs) and 100-yr return-period (RP) metocean events. The latter allows setting PSFs and RP to a prescribed level of system reliability. The 500-yr RP robustness check (appearing in [2] and [3] upcoming editions) is a good indicator of the target reliability for L2 structures. CAE tools such as NREL's FAST and Bentley's' SACS (offshore analysis and design software) can be efficiently coupled to simulate system loads under hurricane DLCs. For this task, we augmented the latest FAST version (v. 8) to include tower aerodynamic drag that cannot be ignored in hurricane DLCs. In this project, a 6 MW turbine was simulated on a typical 4-legged jacket for a mid-Atlantic site. FAST-calculated tower base loads were fed to SACS at the interface level (transition piece); SACS added hydrodynamic and wind loads on the exposed substructure, and calculated mudline overturning moments, and member and joint utilization. Results show that CAE tools can be effectively used to compare design approaches for the design of OWTs in hurricane regions and to achieve a well-balanced design, where reliability levels and costs are optimized.
Tiwary, C. S., E-mail: cst.iisc@gmail.com; Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Chakraborty, S.; Mahapatra, D. R. [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India)
2014-05-28T23:59:59.000Z
This paper attempts to gain an understanding of the effect of lamellar length scale on the mechanical properties of two-phase metal-intermetallic eutectic structure. We first develop a molecular dynamics model for the in-situ grown eutectic interface followed by a model of deformation of Al-Al{sub 2}Cu lamellar eutectic. Leveraging the insights obtained from the simulation on the behaviour of dislocations at different length scales of the eutectic, we present and explain the experimental results on Al-Al{sub 2}Cu eutectic with various different lamellar spacing. The physics behind the mechanism is further quantified with help of atomic level energy model for different length scale as well as different strain. An atomic level energy partitioning of the lamellae and the interface regions reveals that the energy of the lamellae core are accumulated more due to dislocations irrespective of the length-scale. Whereas the energy of the interface is accumulated more due to dislocations when the length-scale is smaller, but the trend is reversed when the length-scale is large beyond a critical size of about 80?nm.
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.
García-Salcedo, Ricardo; Horta-Rangel, Francisco A; Quiros, Israel; Sanchez-Guzmán, Daniel
2015-01-01T23:59:59.000Z
The theory of the dynamical systems is a very complex subject which has brought several surprises in the recent past in connection with the theory of chaos and fractals. The application of the tools of the dynamical systems in cosmological settings is less known in spite of the amount of published scientific papers on this subject. In this paper a -- mostly pedagogical -- introduction to the application in cosmology of the basic tools of the dynamical systems theory is presented. It is shown that, in spite of their amazing simplicity, these allow to extract essential information on the asymptotic dynamics of a wide variety of cosmological models. The power of these tools is illustrated within the context of the so called $\\Lambda$CDM and scalar field models of dark energy. This paper is suitable for teachers, undergraduate and postgraduate students from physics and mathematics disciplines.
Turbulent models of ice giant internal dynamics: Dynamos, heat transfer, and zonal flows
, atmospheric circulation patterns, and thermal emissions that are distinct from other planets in our Solar additional constraints and suggest that these plan- ets may be modeled as three nested regions: (i) an outermost molecular envelope largely composed of hydrogen and helium; (ii) a weakly conducting ionic ocean
Coastal Dynamics 2013 A 3-D PHASE-AVERAGED MODEL FOR SHALLOW WATER FLOW WITH WAVES IN
US Army Corps of Engineers
Coastal Dynamics 2013 1915 A 3-D PHASE-AVERAGED MODEL FOR SHALLOW WATER FLOW WITH WAVES in coastal vegetated waters with short waves. The model adopts the 3-D phase-averaged shallow water flow mesh in the vertical direction. The flow model is coupled with a spectral wave deformation model called
Testa, Paola [Smithsonian Astrophysical Observatory, 60 Garden street, MS 58, Cambridge, MA 02138 (United States); Reale, Fabio, E-mail: ptesta@cfa.harvard.edu [Dipartimento di Fisica, Universita di Palermo, Piazza del Parlamento 1, 90134 Palermo (Italy)
2012-05-01T23:59:59.000Z
We use coronal imaging observations with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), and Hinode/Extreme-ultraviolet Imaging Spectrometer (EIS) spectral data to explore the potential of narrowband EUV imaging data for diagnosing the presence of hot (T {approx}> 5 MK) coronal plasma in active regions. We analyze observations of two active regions (AR 11281, AR 11289) with simultaneous AIA imaging and EIS spectral data, including the Ca XVII line (at 192.8 A), which is one of the few lines in the EIS spectral bands sensitive to hot coronal plasma even outside flares. After careful co-alignment of the imaging and spectral data, we compare the morphology in a three-color image combining the 171, 335, and 94 A AIA spectral bands, with the image obtained for Ca XVII emission from the analysis of EIS spectra. We find that in the selected active regions the Ca XVII emission is strong only in very limited areas, showing striking similarities with the features bright in the 94 A (and 335 A) AIA channels and weak in the 171 A band. We conclude that AIA imaging observations of the solar corona can be used to track hot plasma (6-8 MK), and so to study its spatial variability and temporal evolution at high spatial and temporal resolution.
Ahola, M.; Sagar, B. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses
1992-10-01T23:59:59.000Z
Results of groundwater modeling of the saturated zone in the vicinity of Yucca Mountain are presented. Both a regional (200 {times} 200 km) and subregional (50 {times} 50 km) model were used in the analyses. Simulations were conducted to determine the impact of various disruptive that might take place over the life span of a proposed Yucca Mountain geologic conditions repository on the groundwater flow field, as well as changes in the water-table elevations. These conditions included increases in precipitation and groundwater recharge within the regional model, changes in permeability of existing hydrogeologic barriers, a:nd the vertical intrusion of volcanic dikes at various orientations through the saturated zone. Based on the regional analysis, the rise in the water-table under Yucca Mountain due to various postulated conditions ranged from only a few meters to 275 meters. Results of the subregional model analysis, which was used to simulate intrusive dikes approximately 4 kilometers in length in the vicinity of Yucca Mountain, showed water-table rises ranging from a few meters to as much as 103 meters. Dikes oriented approximately north-south beneath Yucca Mountain produced the highest water-table rises. The conclusions drawn from this analysis are likely to change as more site-specific data become available and as the assumptions in the model are improved.